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[ { "content": "You are a medical writer. Summarize the following article: intracranial vasospasm ( icvs ) can be caused by any situation that brings about bleeding into the cerebral subarachnoid space , such as traumatic subarachnoid hemorrhage ( sah ) , cerebral tumoral bleeding , or rupture of vascular malformations , but the rupture of cerebral aneurysms within the basal cistern is most commonly associated with icvs . \n moreover , migraine , taking vasoactive drugs ( cocaine , pseudoephedrine , immunosuppressants , or selective serotonin reuptake inhibitors ) , or the postpartum period can also cause icvs and tend to induce vasospasm most often without intracranial bleeding . because icvs leads to cerebral ischemia that can cause devastating neurological deterioration in some cases , \n it is important that icvs be detected and its cause be identified as early as possible . \n however , it often results in serious complications , hence appropriate therapeutic approaches and rapid diagnosis are needed . \n icvs associated with spontaneous spinal sdh has also been reported very rarely . here , we firstly report a case of icvs without intracranial hemorrhage that was caused by acute spontaneous spinal sdh . \n a 41-year - old woman was admitted to our hospital with a complaint of severe headache . \n she had headache for 3 years and expressed it as throbbing pain in both temporal regions accompanied by nausea . \n symptoms tended to occur once in 1~2 months , lasted for 1~3 days and then disappeared . a week before admission to our hospital , her headache symptoms were different from those in the past . \n she felt a twinge it the right posterior neck for the first time , and subsequently experienced severe pain in the entire head , but no nausea , vomiting , or fever . \n she was admitted to the neurology department of an outside hospital and underwent computerized tomography ( ct ) angiography 2 days after the headache developed ; no bleeding was noticed yet multifocal vasospasms of intracranial arteries were revealed ( fig . \n she was diagnosed with status migrainosus ; hence , steroid pulse therapy with oral beta - blockers and non - steroidal anti - inflammatory drugs were given to relieve headache . \n several hours before admission to our hospital , she started complaining of nausea and vomiting as well as very sharp tearing pain in the neck and back . according to the analysis of a cerebrospinal fluid ( csf ) specimen that was obtained via lumbar puncture in an outside hospital 3 days after symptom onset , the levels of white blood cells ( wbc ) , protein , and glucose were 4/l , 62 mg / dl , and 46 mg / dl , respectively . \n she had a history of hypertension and her blood pressure was well controlled with regular antihypertensive medication . \n on admission to our hospital , her blood pressure was 195/114 mmhg ; pulse , 60 beats / min ; respiration , 20 breaths / min ; and body temperature , 36.6. mental status was alert and oriented . \n no pathologic reflexes were found , yet neck stiffness was suspected . according to the routine blood tests , the only abnormality was that the wbc count was increased to 18000/l . in the blood coagulation test , prothrombin time - international normalized ratio and activated partial thromboplastin time were 0.99 s ( normal range , 0.00~1.20 s ) and 28 s ( normal range , 20.0~36.0 s ) , respectively ; both values were within the normal range . \n her headache was alleviated , yet pain in the neck and back rapidly worsened and subsequently spread to the whole spine . \n brain magnetic resonance imaging ( mri ) showed no intracranial hemorrhage , such as sah ( fig . \n 1c , d ) . on the same day , transfemoral cerebral angiography ( tfca ) revealed multiple icvss ( fig . \n two hours after tfca , weakness of both legs [ medical research council ( mrc ) grade 0 or i ] , bladder distension , and sensory deficit below both nipples developed . on spinal cord mri \n , we found spinal cord compression by sdh , which was located from the ventral lower cervical to mid - thoracic level ( c7 to t6 ) ( fig . \n the red blood cell count was 340000/l and wbc count was 30/l ( polymorphonuclear leukocytes , 59% ; lymphocytes , 29% ; and mononuclear cells , 12% ) , csf was red , and no color change was observed in the three - tube test . \n emergent total laminectomy was performed through the posterior approach , which was started 7 h after paraplegia . \n while incising the dura , we found that the spinal cord was swollen and large hematoma was present in the subdural and subarachnoid spaces . \n on postoperative day 5 , sensory symptoms and muscle power of the left leg ( mrc grade ii ) partially improved . \n upon the request by the patient 's guardian , the patient was transferred to another hospital on postoperative day 6 . \n three days after the transfer , the patient had weakness and alien hand syndrome of the left arm . \n brain mri showed bilateral multifocal acute infarction of the corpus callosum ; the right side of the lesion was larger than the left side ( fig . \n on ct angiography performed at the other hospital at 8 days after the transfer from our hospital , more exacerbated vasospasms were found in the anterior , posterior , and middle cerebral arteries than initial ct angiography after the headache onset . upon medical treatment , symptoms in the left arm \n four months after discharge from our hospital , she visited our out - patient clinic and no longer had any pain including headache . \n she did not complain of urinary symptoms yet complained of a tingling feeling in both legs . \n the muscle power of both legs and the left arm was approximately mrc grade iv , while the power of the right arm was mrc grade v , which represented considerable improvements in comparison with those parameters at the time of discharge from our hospital . \n about 1 year after symptom onset , muscle power recovered to an almost normal level in both legs and arms . \n follow - up magnetic resonance angiography revealed no vasospasms in any of the intracranial arteries ( fig . \n as opposed to the brain , the subdural cavity of the spinal cord lacks a bridging vein ; thus , the mechanisms of spinal sdh development are still unclear . although subdural reticular anastomosis can be damaged during lumbar puncture , it is very unlikely to explain sdh , given the size of the vessels . \n rader suggested that sdh might be caused by indirect force delivered to the vessels in the spinal cord . \n a sudden rise in intra - abdominal or intra - thoracic pressure is known to increase the inner pressure in subdural and subarachnoid vessels , thereby subsequently resulting in their rupture . \n the radiculomedullary arteries and veins in the subarachnoid cavity are large enough to cause bleeding . in the early stage of bleeding \n , a blood clot may not form because of the redistribution and dilution of the blood by the csf flow . as bleeding progresses \n , clots of considerable size can form , which may be sufficient to block the csf flow ; csf flow stagnation can increase the buildup of clots in the subarachnoid space , which eventually leads to a rupture of the arachnoid membrane , thereby causing sdh . in our patient , \n pain started initially in the posterior neck , then spread to the entire head , and then to the whole spine . \n after the development of these symptoms , transverse myelopathy symptoms ( paraplegia , bladder distension , and sensory deficit below both nipples ) developed . \n furthermore , the fact that bleeding was found in the subarachnoid space during surgery indicates that sah at the upper thoracic level had spread out to the intracranial cavity and caused icvss , which presumably led to headache ; with further progression of the subarachnoid hemorrhage at the thoracic level , the csf flow may have been hindered , in turn resulting in clot enlargement . \n consequently , these clots may have led to sdh development and subsequently induced spinal cord compression . taking into account these speculations , the hypothesis of calhoun and boop appears to more reasonably explain the mechanisms of spinal sdh than hypotheses of the others in this case . \n however , sah was not observed on brain mri or ct . in a previous report \n , the rate of sah diagnosis varied depending on the time from symptom onset to ct imaging . \n the delay was associated with the lower sensitivity of sah diagnosis ( 98~100% within the first 12 h , 93% within 24 h , 57~85% after 6 days ) . on spinal cord mri of our patient , \n additionally , radiologic modalities such as mri or ct are known not to be able to differentiate between subarachnoid and subdural hemorrhage . \n therefore , we may have not detected sah because 1 ) the patient underwent brain imaging too late ( initial brain imaging was performed 2 days after symptom onset ) or 2 ) the spread of the hemorrhage into the cranial cavity was limited . in a recent report , \n shakur and farhat presented a case similar to ours . however , unlike in our case , they confirmed cortical sah and ventricular hemorrhage by ct . major symptoms of acute spinal sdh include sudden - onset pain in the back and neck , radicular pain , as well as myelopathy symptoms ( e.g. , paraplegia , paresthesia , and dysuresia ) . \n the risk factors for spinal sdh include the use of anticoagulants , coagulopathy , vascular malformations , spinal infection , and tumors . \n the characteristics of previous headache that our patient had for 3 years seemed to indicate that she suffered from migraine . \n our patient initially presented with headache , whereas myelopathy symptoms developed later , after the first lumbar puncture . \n however , the characteristics of her headache at admission to the outside hospital were different from previous symptom of headache , and spinal sdh was located from the lower cervical to mid - thoracic segment . if spinal sdh had been caused by the lumbar puncture , spinal sdh would have been found around the lumbar area . \n thus , we do not believe that the lumbar puncture caused spinal sdh . according to domenicucci et al . \n , in 15% out of 106 cases , the causes of non - traumatic subdural spinal hematomas were unknown . \n our patient did not have any risk factors for hemorrhage and complained of severe headache in the early stage ; imaging revealed no hemorrhage ( e.g. , sah ) , while vasospasms were clearly established . \n it has been suggested that emergency surgical decompression is critical to determine prognosis in patients with acute spinal sdh . \n therefore , it is important to note that there is a possibility of acute spontaneous spinal sdh in patients with headache who have icvs despite no intracranial hemorrhage detected by brain imaging .", "role": "user" }, { "content": "spontaneous spinal subdural hematoma ( sdh ) is very rare . \n furthermore , intracranial vasospasm ( icvs ) associated with spinal hemorrhage has been very rarely reported . \n we present an icvs case without intracranial hemorrhage following sdh . \n a 41-year - old woman was admitted to our hospital with a complaint of severe headache . \n multiple intracranial vasospasms were noted on a brain ct angiogram and transfemoral cerebral angiography . \n however , intracranial hemorrhage was not revealed by brain mri or ct . on day 3 after admission , weakness of both legs and urinary incontinence developed . \n spine mri showed c7~t6 spinal cord compression due to hyperacute stage of sdh . \n after hematoma evacuation , her symptoms gradually improved . \n we suggest that spinal cord evaluation should be considered in patients with headache who have icvs , although intracranial hemorrhage would not be visible in brain images .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: intestinal stricture is a major complication that may occur during or after chemotherapy for gastrointestinal lymphoma . \n the recently developed technique of balloon endoscopy allows for diagnosis of small intestinal lesions as well as for performing several endoscopic therapies , such as balloon dilation of small intestinal stenosis in crohn 's disease . here \n , we report a case in whom endoscopic dilation under balloon endoscopy was very useful for treating a stricture of the small intestine that occurred during chemotherapy for malignant lymphoma . \n a 78-year - old woman presented at our hospital with complaints of loss of appetite for 6 months . on admission , she appeared undernourished ( height 159.5 cm , weight 45.5 kg ) , and had a regular pulse rate of 91 beats per minute , a blood pressure of 129/51 mm hg , and a temperature of 37.7c . \n physical examination revealed enlarged lymph nodes in the cervical , axillary , and supraclavicular regions and conjunctival anemia . \n laboratory data were as follows : white blood cell count 9,500/l ( normal 3,500 - 7,000 ) , hemoglobin 8.7 g / dl ( normal 11.7 - 15.8 ) , platelets 18.1 10/l ( normal 14.0 - 35.0 10 ) , lactate dehydrogenase 533 iu / l ( normal 80 - 230 ) , total protein 5.1 g / dl ( normal 6.0 - 8.0 ) , albumin 2.9 g / dl ( normal 4.0 - 5.0 ) , c - reactive protein 2.4 mg / dl ( normal 0.0 - 0.5 ) , ferritin 602 ng / ml ( normal 3.6 - 114.0 ) , soluble interleukin 2 receptor 8,100 u / ml ( normal 145 - 519 ) . \n computed tomography ( ct ) scans showed systemic lymph node enlargement and increased gastric and distal ileal wall thickness ( fig . \n she was admitted to our hospital for chemotherapy ( rituximab , cyclophosphamide , hydroxydaunorubicin , vincristine , and prednisolone [ r - chop ] regimen ) . \n an ileus tube was inserted and a small intestinal series through the ileus tube showed severe stenosis of the ileum approximately 50 cm proximal to the ileocecal valve ( fig . \n we considered it necessary to treat this small intestinal stricture as quickly as possible because the patient required additional chemotherapy for swelling of abdominal lymph nodes suggestive of residual lymphoma . \n after informed consent was obtained from the patient and her family , we performed endoscopic dilation therapy with a single - balloon endoscopy ( sif - q260 ; olympus co. , ltd , tokyo , japan ) . \n the balloon catheter was inserted into the stenotic site through the scope channel ( fig . \n the balloon was only dilated up to 9 mm in diameter and dilation time was only 60 s because the patient complained of mild abdominal pain when the balloon diameter reached 9 mm . \n eight months after this procedure , her symptoms had not recurred and 6 cycles of chemotherapy were uneventfully performed , resulting in complete disease remission . \n this is a case of successful treatment with endoscopic balloon dilation for a small intestinal stricture that occurred during chemotherapy for malignant lymphoma . \n most small intestinal strictures resulting from chemotherapy of malignant lymphoma are treated surgically because of the risk of perforation . in this case , however , the patient still required additional chemotherapy for residual malignant lymphoma when the stricture of the small intestine appeared . \n therefore , instead of surgical treatment , we selected endoscopic balloon dilation therapy so that r - chop could be continued with minimal interruption . as a result , \n the patient was able to resume chemotherapy immediately after endoscopic balloon dilation and achieved clinical remission . \n endoscopic balloon dilation is considered a standard therapy for strictures related to inflammatory lesions and anastomotic strictures of the large and small intestine [ 7 , 8 ] . \n in particular , a significant proportion of patients with crohn 's disease develop strictures that result in recurrent obstructive symptoms . therefore , most symptomatic patients with crohn 's disease require further intervention , either surgery or endoscopic dilation . of these treatment options , balloon dilation has the advantage of being safe and to preserve intestinal length . \n thus , endoscopic dilation therapy is an established treatment for patients with crohn 's disease who have stenotic symptoms . whether endoscopic dilation therapy is safe and applicable for intestinal strictures related to malignant lymphoma that occur during or after chemotherapy remains unclear , however , because of \n we have summarized four cases in which endoscopic dilation therapy was used for intestinal strictures related to malignant lymphoma , including the present case ( table 1 ) . in three of the four cases ( 75% ) , successful endoscopic dilation therapy was performed without complication , and perforation occurred in the other case . \n reported that balloon dilation through a scope using double - balloon endoscopy is likely to be a useful palliative treatment option for otherwise difficult to manage small intestinal strictures complicating lymphoma patients . in the present case , the small intestinal stricture occurred during chemotherapy , which is different from the other cases in whom the strictures occurred after chemotherapy . \n generally , intestinal stricture related to malignant lymphoma is considered to be more fragile than that of non - malignant lesions such as crohn 's disease . \n therefore , prior to dilation therapy for intestinal stricture related to malignant lymphoma , we deliberately evaluate whether or not residual tumor exists at the stenotic site for which dilation therapy would be performed . in the present case , both endoscopic and ct findings demonstrated no visible tumor at the stenotic site , suggesting that this stenotic lesion was indicated for dilation therapy . \n however , we should keep in mind performing it for intestinal stenosis related to malignant lymphoma more deliberately than for that of crohn 's disease . \n although surgical treatment might have been an option for this patient , the patient could not have undergone additional chemotherapy for the residual malignant lymphoma immediately after the treatment . \n thus , in this case , endoscopic , although maybe only palliative therapy , was considered . cho et al . reported a case of perforation after endoscopic balloon dilation for an intestinal stricture of malignant lymphoma , in whom perforation occurred at the second trial of the dilation therapy 14 months after the first dilation therapy . \n first , an intestinal stricture related to malignant lymphoma can recur , similar to that in patients with crohn 's disease , after dilation therapy . \n patients with lymphoma whose intestinal strictures are treated by endoscopic dilation therapy should therefore be carefully followed up . in addition , because repeated dilation therapy with increased balloon dilation size for intestinal stricture could increase the risk of perforation , examination with endoscopic ultrasonography before dilation therapy to check the status of the wall structure may be necessary . \n the extent of an intestinal stricture dilated safely by endoscopic therapy as well as the size of dilation safely performed is unclear at present . in our case \n , we dilated the stricture up to only 9 mm due to complaints of abdominal pain by the patient during dilation therapy and finished only 60 s. the patient 's stenotic symptoms were ameliorated , however , and subsequent chemotherapy was uneventfully performed , resulting in disease remission . \n thus , the goal of dilation therapy is not excessive dilation but sufficient dilation to relieve the patient 's symptoms . in conclusion , \n the present case report supports the usefulness of endoscopic dilation therapy for intestinal stricture related to malignant lymphoma . \n careful consideration of the cases indicated for endoscopic dilation therapy , however , is necessary .", "role": "user" }, { "content": "we report a stricture occurring during chemotherapy for malignant lymphoma that was successfully treated by endoscopic balloon dilation . \n the patient was diagnosed with stage iv malignant lymphoma by esophagogastroduodenoscopy and computed tomography scans . \n she complained of nausea and vomiting after undergoing the second cycle of chemotherapy . a small intestinal series through an ileus tube showed severe stricture of the ileum . \n endoscopic balloon dilation was successfully performed with single - balloon endoscopy . \n after the procedure , her symptoms subsided and did not recur even 8 months after endoscopic dilation therapy .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: videolaryngoscopes are relatively new devices available for intubation , which provide several potential advantages over direct laryngoscopy including better views of the larynx , particularly in patients with limited cervical spine motion , reduced tracheal intubation time , and educational value . \n macgrath videolaryngoscope ( aircraft medical , edinburgh , uk ) is a relatively new device . the aim of our study was to evaluate the efficacy of macgrath videolaryngoscope in nasotracheal intubation using schroeder directional stylet . \n we hypothesized that better glottic view and changing curvature of the endotracheal tube would make nasal intubation easy with these devices . \n after obtaining approval from the institutional ethical committee , 15 adult patients undergoing tonsillectomy requiring nasotracheal intubation were recruited . \n we included patients if they were > 18 years of age , american society of anesthesiologists grades i and ii , and had a modified mallampati score of 1 or 2 . \n exclusion criteria included the presence of predictors of difficult intubation , including decreased inter - incisor distance ( <3 cm ) , short thyromental distance ( < 6 cm ) , and reduced neck extension ( < 80 from neck flexion ) , cervical spine instability , or risk of pulmonary aspiration . \n we also recorded overall success rate , number of attempts , modified cormack - lehane ( c - l ) grading and complications . after obtaining written informed consent , \n each patient was premedicated with dexamethasone 4 mg , midazolam 0.05 mg / kg , fentanyl 2 g / kg and glycopyrrolate 0.02 mg . \n after preoxygenation with 100% o2 , anesthesia was induced using the drugs of the treating anesthetist 's choice . \n the lungs were then ventilated with 100% o2 using a bag and a mask , and laryngoscopy was attempted . \n the mcgrath videolaryngoscope series five was inserted into the patient 's mouth along the midline of the tongue , and the blade was advanced until the larynx became visible on the screen . \n a standard oral tracheal tube was used ( size 6.5 for females and size 7.5 for males ) . a well - lubricated schroeder directional stylet ( stebar instrument corp . , grand rapids , mi , usa ) was passed into the tube . \n when the vocal cord was visible on liquid - crystal display monitor of the laryngoscope , endotracheal tube with schroeder stylet was inserted into one of the nares . after negotiating through nasopharynx and subsequently oropharynx , \n then the lever on the proximal end of the schroeder stylet was depressed , which led to alteration of the curvature of the stylet with consequent anterior flexion of the tube leading to its smooth navigability anteriorly towards the vocal cord . \n after passing the tube through the glottic opening , which was visualized on the video screen , the lever of the stylet was released and the stylet was then removed and the nasotracheal tube was further guided into the trachea , achieving successful nasotracheal intubation . \n the duration of intubation was defined as time from when the videolaryngoscope was inserted into the participant 's mouth until end - tidal co2 was detected . \n the ease of intubation was graded by the intubating anesthetist on a numerical rating scale ( nrs , where 0 was the most difficult and 10 the easiest ) . \n the best laryngoscopic view obtained using the c - l classification , number of attempts at laryngoscopy required to intubate the trachea ( insertion and removal of the laryngoscope counted as one laryngoscopy ) , any airway complications , episodes of hypoxia ( spo2<92% ) and/or equipment failure were also recorded . during desaturation or failure to intubate , \n patient characteristics and the results of the preoperative airway assessment are shown in the table 1 . \n tracheal intubation was successfully completed in all patients using the mcgrath videolaryngoscope , and all 15 intubations were successful during first laryngoscopy attempt . \n c - l grade i views were obtained in 14 patients ( 93% ) and grade ii view in one patient ( 7% ) . \n the time required to obtain the best c - l view was 9.4 1.5 s. the time taken to complete tracheal intubation was 34.27 3.38 s. average nrs for tracheal intubation was 8.7 0.9 . \n minor complications occurred in four patients ( 26.7% ) : oxygen saturation decreased below 92% in one patient , and airway trauma was observed in three patients . \n this case series demonstrates a high success rate of nasotracheal intubation in adult patients with macgrath videolaryngoscope using schroeder 's directional stylet . \n the average time taken to complete tracheal intubation was 34.27 3.38 s. this duration of intubation is less than the other reported studies . \n ng et al . have reported 67 s to intubate with mcgrath in potential difficult airways . according to jeon et al . \n tracheal intubation time is 40.5 s. hirabayashi and seo in their study have reported nasotracheal intubation time with airtraq and macintosh laryngoscope was 15 11 s and 13 6 s , respectively . \n removal of the stylet , after intubation , might have increased the time in our study . \n however , we did not find any significant studies reporting nasal intubation with macgrath videolaryngoscope using schroeder stylet . \n ng et al . also reported similar result in their study with normal airway situation . according to them , \n ease of intubation was 8 in rating scale and it is comparable to our study . \n shippey et al . also reported similar success rate , but in their study , they intubated patients through orotracheal route . \n all our patients were intubated on the first attempt , which is similar to the studies of walker et al . where they stated 97% success rate on first attempt with macgrath . \n we found c - l grade i in 93% ( 14 of 15 patients ) , which is similar to other studies on macgrath . \n first , due to the small sample size of our study , even a small number of complications will lead to the high percentage . \n second , chances of airway trauma is more while intubating a patient through nasotracheal route compared to the orotracheal route . \n we acknowledge the limitations in drawing conclusions from a case series reported from a single center . \n patients were unselected , not enrolled consecutively , no control group was used , and measurements were not blinded . \n however , we collected data consistently , prospectively and according to a protocol designed before the case series began . \n this approach should reduce any potential bias , and as no patient was withdrawn from the case series , should mitigate against problems of data interpretation . \n nevertheless , we believe that this case series provides useful clinical information about the nasotracheal intubation with mcgrath videolaryngoscope using schroeder directional stylet . \n the compact , fully self - contained , and portable mcgrath videolaryngoscope produces excellent laryngoscopic views in patients with normal airways . \n impaction of tracheal tube on posterior nasopharyngeal wall was overcome by schroeder stylet . by increasing the curvature of the tube using this stylet , negotiation of the tube through \n furthermore , tracheal tube cuff damage is possible while grasping the tube with magill 's forceps . \n is easier than removal of malleable stylet . finally , randomized controlled trials are warranted to compare the utility of this device compared with other videolaryngoscopes and advanced airway devices in patients undergoing nasotracheal intubation .", "role": "user" }, { "content": "background and aims : macgrath videolaryngoscope is one of the recent videolaryngoscopes , which can be used to facilitate nasotracheal intubations using scroeder directional stylet.material and methods:15 patients , american society of anesthesiologists grades i - ii , undergoing tonsillectomy , requiring nasotracheal intubation were included . \n all patients were intubated with macgrath videolaryngoscope and schroeder stylet . \n primary outcome measures \n were duration and ease of intubation . overall success rate , number of attempts , modified cormack - lehane ( c - l ) grading , and complications were also recorded.results:all 15 intubations were successful during first laryngoscopy attempt . \n c - l grade i views were obtained in 14 patients ( 93% ) and grade ii view in one patient ( 7% ) . \n the time required to obtain the best c - l view was 9.4 1.5 s. the time taken to complete tracheal intubation was 34.27 3.38 s. average numerical rating scale for tracheal intubation was 8.7 0.9 . \n minor complications occurred in four patients ( 26.7%).conclusions : macgrath videolaryngoscope produces excellent laryngoscopic views in patients with normal airways . \n impaction of tracheal tube on posterior nasopharyngeal wall can be overcome by schroeder stylet .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: the first step in setting up the experiments involves preparing the fly so that no involuntary motion corrupts the stability of the neuronal recordings and that the head of the fly is correctly oriented with the visual stimulation equipment . to begin preparing the fly , cool it on ice and then use blunted cocktail sticks to hold the wings down , and fix the back of the fly to a piece of double - sided - tape on a microscope slide . \n next , use an electro - cauterizing needle to apply bees wax to attach the wings to the slide and also to block the action of the flight motor . \n this step requires quick and accurate handling so that the fly does not warm up during the procedure . now under the microscope , hold each leg with forceps and use a pair of small scissors to cut them off at the joints closest to the body . repeat this for the proboscis . to prevent the fly from drying out , \n next , cut one of the wings off and then turn the fly on its side . remove any remaining pieces of wing , while leaving the calyptra covering the halteres , and seal the hole with wax . \n repeat this procedure for the other wing . to stimulate a target neuron in a defined way \n , the fly 's head has to be properly aligned with the computer monitors . to do this \n , you will need a customized holder that has a broad space for the fly 's body and an appendage on one end with a notch cut where the fly 's neck will be placed . \n place the fly onto the holder with its neck in the notch , pressing it down while gluing the abdomen in place . \n now place the fly holder in a stand so that you can see the front of the fly 's head through the microscope . \n viewing the fly with red light , an optical phenomenon called the pseudo - pupil can be seen in each eye . \n the pseudo - pupil provides a reference frame which can be used to align the fly 's head with the stimulus ( franceschini 1975 ) . if the pseudo - pupil assumes a certain shape , as shown by the image insert below , then the orientation of the fly 's head is perfectly defined . \n use a micromanipulator to correctly orient the fly 's head , and then use wax to glue it to the holder . \n this allows the rear head capsule to be opened so that electrodes can be inserted into the fly brain . \n use a micro scalpel or a fine injection needle to carefully cut a window into the cuticle of the right head capsule . \n once the piece of cuticle is removed , add a few drops of ringer solution . \n use forceps to remove any floating hairs , fat deposits , or muscle tissue that may cover the lobula plate . \n the lobula plate can be identified by a characteristic branching pattern of silvery trachea that covers its posterior surface . \n cut a small hole into the cuticle of the left rear head capsule for positioning a reference electrode . with the fly prepared , \n the h1 neuron mainly responds to horizontal back - to - front motion presented to its receptive field ( krapp et al . \n 2001 ) . to position the recording electrode , use the trachea as a visual landmark . \n it helps to use an audio amplifier to convert the recorded electrical potentials into acoustic signals . \n the closer the electrode gets to an individual neuron , the clearer the clicking sound becomes . to identify the h1 neuron by means of its motion preference , stimulate it with motion in the horizontal direction . with the recording electrode in place , lets move on to visual stimulation and recordings . \n the closed - loop experiments are setup such that such that stimulation of the h1 neuron results in the robot compensating for the movement of the turn - table . to begin , place a fly in front of two crt computer monitors . \n because the fly visual system is 10 times faster than the human s , the monitors must display 200 frames per second . \n the monitors and other electrical equipment must be electromagnetically shielded to minimize external noise in the measured neuronal signal . \n as seen from the fly 's eye equator , each monitor subtends an angle of + /-25 degrees in the horizontal , and + /-19 degrees in the vertical plane . \n synchronized input to the computer monitors is provided by two video cameras mounted on a small , two - wheeled asuro robot that has been modified for the experiment . \n position the robot on a turn - table within a cylindrical area whose walls are lined with a pattern of vertically oriented , black and white stripes . by rotating the turn - table in the horizontal plane , the movements of the robot are limited to only one degree of freedom . initially \n when the turn - table starts moving , its rotation carries the robot , in the same direction and the video cameras record the relative motion between the robot and the striped pattern of the arena . \n the battery - powered video cameras on the robot are mounted at an orientation of + /- \n they capture 200 images per second to match the frame rate of the computer monitors in front of the fly . \n log the images presented to the computer monitors at 200 frames per second at a resolution of 640 x 480 ( gray - scale ) . \n while the fly is watching the movements of the striped pattern , record the band - passed filtered ( for example , between 300 and 2 khz ) electrical signals with a digital acquisition board using a sampling rate of at least 10 khz . \n a threshold is applied to the band - passed filtered electrical signals to separate the spikes from the background activity . \n a causal , half - gaussian filter is convolved with the spikes to obtain a smooth spiking activity estimate for the h1 cell . to close the loop of the brain machine interface , \n a control algorithm is used to convert the spike rate of the h1 cell to a robot speed which is fed back via a bluetooth interface to control the two dc motors driving the wheels of the robot . \n the sine waves have a dc - offset such that the turn - table only rotates in the direction which stimulates the h1 neuron along its preferred direction . \n stimulation of the h1 neuron results in the robot compensating for the movement of the turn-table.figure 1 : closed loop setup . in our setup , spiking activity of the left h1 cell is used to control the motion of a robot mounted on a turntable . visual image motion generated as a result of relative motion between the robot and the turn - table \n is captured via high - speed cameras and displayed on two crt monitors in front of the fly . \n h1 spiking activity from the left hemisphere is used to estimate the real - time spike rate which then uses a control law to calculate a compensation speed for the robot . \n the robot counter - rotation stabilizes the visual image motion observed by the fly during closed - loop control . \n when set up correctly , visual stabilization is achieved when the counter - rotation of the robot matches the rotation of the turn - table , resulting in little or no pattern movement on the computer monitors . \n the overall performance of the system depends on the control algorithm being used to close the loop . \n the first algorithm we test is a proportional controller ( figure 2 ) where the updated robot speed is proportional to the difference in angular velocities between the robot , r , and the turn - table , p . \n different values for the static gain , kp , and input frequencies for the turn - table signal , p , are chosen to test the performance of the controller.figure 2 : proportional controller . \n ( a ) relative motion between the robot and the turn - table in the preferred direction stimulates the h1 cell to give the spike rate , f. this spike rate is converted into a speed error , e , and a proportional controller is used to estimate the updated robot speed , vr(t+1 ) . \n the spike rate , f , is converted to the speed error , e , based on whether it is less than or greater than the spontaneous spike rate , fspont . the spike rate to speed error conversion \n is done by projecting f over a cosine ( interval [ ,0 ] ) to account for spiking rate threshold nonlinearities . \n the constants 70 and 150 are used to match the 8-bit input speed of the robot to the minimum and maximum angular velocities of the turn - table . \n the input to the system is a sinosuidal modulation of the turn - table angular velocity , p(t ) , and the corresponding robot response r(t+1 ) is recorded . \n sample traces for p and r are shown here for kp=1 and an input frequency of 0.6 hz for p ( see figure 3 ) . \n the robot ( in green ) follows the turn - table ( in blue ) with a lag and a smaller peak - amplitude . \n the horizontal component of the pattern motion that stimulates the h1 cell is shown below ( in red).figure 3 : closed loop responses . \n ( a ) angular velocities for the turn - table ( blue ) , p , and robot ( green ) , r , at input frequency = 0.6 hz . ( b ) \n pyramidal lucas kanade method ( 3 pyramid levels ) is used to compute the optic flow field between successive image frames . \n horizontal angular velocity is calculated by summing the projections of individual vectors in the flow fields onto the horizontal unit vector i. horizontal back - to - front motion that excites the h1 cell is referred to as pd ( preferred direction ) while horizontal front - to - back motion that inhibits the h1 cell is referred to as nd ( null direction ) . \n input frequencies for the turn - table signal , p , are chosen between 0.03 - 3 hz and the corresponding robot signal , r , is recorded . \n both signals are transformed into the frequency domain by a fast fourier transform ( see figure 4 ) and the amplitude and phase values are calculated at the input frequency.figure 4 : frequency response . \n angular velocity signals for the turn - table , p , and robot , r , are transformed into the frequency domain using the fast fourier transform ( fft ) method to calculate amplitude and phase components at the input frequency . \n the bode magnitude plot for the proportional controller with kp=1 shows the response of the system over the tested input frequencies ( see figure 5-a ) . \n the performance of the controller generally decreases with increasing frequencies . the slightly increased gain at 1 hz is as a result of oscillations in the robot signal due to using only one h1-cell whose dynamic ( output ) range mainly covers horizontal back - to - front motion.figure 5 : proportional controller performance . \n the bode magnitude and phase plots for the proportional controller ( averaged over 8 flies ) , static gain kp = 1.0 ( a ) the bode magnitude plot roughly follows a low pass filter characteristic . the slightly increased gain at 1 hz is as a result of oscillations in the robot signal , r , due to using only one h1-cell whose dynamic ( output ) range mainly covers horizontal back to front motion . \n the number of oscillations in the robot signal , r , decrease with increasing input frequencies leading to slightly increased gain at these frequencies . \n ( b ) the bode phase plot is less than 180 for input frequencies 1 hz and approaches instability at 3 hz . beyond a certain input frequency , \n this instability only occurs beyond the known optimal response range of the fly visual system ( warzecha et al . \n the bode phase plot ( see figure 5-b ) shows a controller phase lag less than for input frequencies < 0.6 hz . \n this shows that the controller is stable for frequencies < 0.6 hz and unstable for input frequencies 1 hz . the performance of the proportional controller with a static kp ( in blue ) was compared with an adaptive controller ( in red ) , where the value for kp is updated every 50 ms based on the peak spike rate , fmax , calculated over time interval [ t-500ms - t ] ( see figure 6 ) . as a result of the large integration time window \n , the proportional controller performs better than the adaptive controller for the parameter range tested ( see figure 7-a ) . \n the initial time integration window of 500 ms was chosen for technical reasons related to the robot platform we are using . \n the adaptive controller had a similar phase characteristic as the proportional controller ( see figure 7-b ) . \n the proportional controller uses a static gain , kp , whereas the adaptive controller estimates the gain continuously during closed loop control . \n the dynamic gain , kp , is inversely proportional to the maximum spike rate , fmax , over the interval t-500ms \n t. figure shows three instances where fmax is estimated over time . based on estimated values of fmax , \n kp is highest during time window 2 ( green ) and lowest during time window 3 ( orange ) . \n bode magnitude and phase plots for the proportional ( kp = 1 ) and adaptive controller ( a ) the adaptive controller updates the value of kp every 50ms based on the peak spike rate estimate fmax over the last 500ms . the proportional controller gain plot ( blue ) is higher than that of the adaptive controller ( red ) indicating that it is performing better at all input frequencies . \n ( b ) the bode phase plots for both controllers are similar with a significant difference at f = 0.3 hz . both controllers approach instability at 3 hz . \n significantly different gain and phase values are indicated by an asterix ( wilcoxon rank sum method , p = 0.05 ) . \n the grating pattern around the turntable was removed and the lab environment was used as an approximation of naturalistic visual input for the fly h1-cell . on average , the bode magnitude plot ( see figure 8-a ) for the naturalistic visual input ( in blue ) showed slightly higher gains than the one with grating visual input ( in red ) probably because the wider range of spatial frequencies in naturalistic visual images is exploited . \n the bode phase plot characteristics for grating vs naturalistic visual inputs were similar ( see figure 8-b).figure 8 : stripped pattern vs. lab environment . \n the bode magnitude and phase plots for the proportional controller when presented with stripped patterns ( red ) vs lab environment ( blue ) visual images under closed loop ( a ) the bode magnitude plot for when lab environment images are used is marginally higher than when stripped pattern is used ( except at f = 0.1 hz ) indicating better performance under such stimulus . ( \n b ) the bode phase plot under both visual conditions follow the same pattern , with both approaching instability at 3 hz . \n significantly different gain and phase values are indicated by an asterix ( wilcoxon rank sum method , p = 0.05 ) . \n the first step in setting up the experiments involves preparing the fly so that no involuntary motion corrupts the stability of the neuronal recordings and that the head of the fly is correctly oriented with the visual stimulation equipment . to begin preparing the fly , cool it on ice and then use blunted cocktail sticks to hold the wings down , and fix the back of the fly to a piece of double - sided - tape on a microscope slide . \n next , use an electro - cauterizing needle to apply bees wax to attach the wings to the slide and also to block the action of the flight motor . \n this step requires quick and accurate handling so that the fly does not warm up during the procedure . now under the microscope , hold each leg with forceps and use a pair of small scissors to cut them off at the joints closest to the body . repeat this for the proboscis . to prevent the fly from drying out , \n next , cut one of the wings off and then turn the fly on its side . remove any remaining pieces of wing , while leaving the calyptra covering the halteres , and seal the hole with wax . \n repeat this procedure for the other wing . to stimulate a target neuron in a defined way \n , the fly 's head has to be properly aligned with the computer monitors . to do this \n , you will need a customized holder that has a broad space for the fly 's body and an appendage on one end with a notch cut where the fly 's neck will be placed . \n place the fly onto the holder with its neck in the notch , pressing it down while gluing the abdomen in place . \n now place the fly holder in a stand so that you can see the front of the fly 's head through the microscope . \n viewing the fly with red light , an optical phenomenon called the pseudo - pupil can be seen in each eye . \n the pseudo - pupil provides a reference frame which can be used to align the fly 's head with the stimulus ( franceschini 1975 ) . if the pseudo - pupil assumes a certain shape , as shown by the image insert below , then the orientation of the fly 's head is perfectly defined . \n use a micromanipulator to correctly orient the fly 's head , and then use wax to glue it to the holder . \n this allows the rear head capsule to be opened so that electrodes can be inserted into the fly brain . \n use a micro scalpel or a fine injection needle to carefully cut a window into the cuticle of the right head capsule . \n once the piece of cuticle is removed , add a few drops of ringer solution . \n use forceps to remove any floating hairs , fat deposits , or muscle tissue that may cover the lobula plate . \n the lobula plate can be identified by a characteristic branching pattern of silvery trachea that covers its posterior surface . \n cut a small hole into the cuticle of the left rear head capsule for positioning a reference electrode . with the fly prepared , \n with the fly prepared , let s proceed to locating and recording signals from the h1 neuron . \n the h1 neuron mainly responds to horizontal back - to - front motion presented to its receptive field ( krapp et al . \n 2001 ) . to position the recording electrode , use the trachea as a visual landmark . \n it helps to use an audio amplifier to convert the recorded electrical potentials into acoustic signals . \n the closer the electrode gets to an individual neuron , the clearer the clicking sound becomes . to identify the h1 neuron by means of its motion preference , \n stimulate it with motion in the horizontal direction . with the recording electrode in place , lets move on to visual stimulation and recordings . \n the closed - loop experiments are setup such that such that stimulation of the h1 neuron results in the robot compensating for the movement of the turn - table . to begin , place a fly in front of two crt computer monitors . \n because the fly visual system is 10 times faster than the human s , the monitors must display 200 frames per second . \n the monitors and other electrical equipment must be electromagnetically shielded to minimize external noise in the measured neuronal signal . \n as seen from the fly 's eye equator , each monitor subtends an angle of + /-25 degrees in the horizontal , and + /-19 degrees in the vertical plane . \n synchronized input to the computer monitors is provided by two video cameras mounted on a small , two - wheeled asuro robot that has been modified for the experiment . \n position the robot on a turn - table within a cylindrical area whose walls are lined with a pattern of vertically oriented , black and white stripes . by rotating the turn - table in the horizontal plane , the movements of the robot are limited to only one degree of freedom . \n initially both the turn - table and robot are at rest . when the turn - table starts moving , its rotation carries the robot , in the same direction and the video cameras record the relative motion between the robot and the striped pattern of the arena . \n the battery - powered video cameras on the robot are mounted at an orientation of + /- \n they capture 200 images per second to match the frame rate of the computer monitors in front of the fly . \n log the images presented to the computer monitors at 200 frames per second at a resolution of 640 x 480 ( gray - scale ) . \n while the fly is watching the movements of the striped pattern , record the band - passed filtered ( for example , between 300 and 2 khz ) electrical signals with a digital acquisition board using a sampling rate of at least 10 khz . \n a threshold is applied to the band - passed filtered electrical signals to separate the spikes from the background activity . \n a causal , half - gaussian filter is convolved with the spikes to obtain a smooth spiking activity estimate for the h1 cell . to close the loop of the brain machine interface , \n a control algorithm is used to convert the spike rate of the h1 cell to a robot speed which is fed back via a bluetooth interface to control the two dc motors driving the wheels of the robot . \n the sine waves have a dc - offset such that the turn - table only rotates in the direction which stimulates the h1 neuron along its preferred direction . \n stimulation of the h1 neuron results in the robot compensating for the movement of the turn-table.figure 1 : closed loop setup . in our setup , spiking activity of the left h1 cell is used to control the motion of a robot mounted on a turntable . visual image motion generated as a result of relative motion between the robot and the turn - table \n is captured via high - speed cameras and displayed on two crt monitors in front of the fly . \n h1 spiking activity from the left hemisphere is used to estimate the real - time spike rate which then uses a control law to calculate a compensation speed for the robot . \n the robot counter - rotation stabilizes the visual image motion observed by the fly during closed - loop control . \n when set up correctly , visual stabilization is achieved when the counter - rotation of the robot matches the rotation of the turn - table , resulting in little or no pattern movement on the computer monitors . \n the overall performance of the system depends on the control algorithm being used to close the loop . \n the first algorithm we test is a proportional controller ( figure 2 ) where the updated robot speed is proportional to the difference in angular velocities between the robot , r , and the turn - table , p . \n different values for the static gain , kp , and input frequencies for the turn - table signal , p , are chosen to test the performance of the controller.figure 2 : proportional controller . \n ( a ) relative motion between the robot and the turn - table in the preferred direction stimulates the h1 cell to give the spike rate , f. this spike rate is converted into a speed error , e , and a proportional controller is used to estimate the updated robot speed , vr(t+1 ) . \n the spike rate , f , is converted to the speed error , e , based on whether it is less than or greater than the spontaneous spike rate , fspont . the spike rate to speed error conversion \n is done by projecting f over a cosine ( interval [ ,0 ] ) to account for spiking rate threshold nonlinearities . \n the constants 70 and 150 are used to match the 8-bit input speed of the robot to the minimum and maximum angular velocities of the turn - table . \n the input to the system is a sinosuidal modulation of the turn - table angular velocity , p(t ) , and the corresponding robot response r(t+1 ) is recorded . \n sample traces for p and r are shown here for kp=1 and an input frequency of 0.6 hz for p ( see figure 3 ) . \n the robot ( in green ) follows the turn - table ( in blue ) with a lag and a smaller peak - amplitude . \n the horizontal component of the pattern motion that stimulates the h1 cell is shown below ( in red).figure 3 : closed loop responses . \n ( a ) angular velocities for the turn - table ( blue ) , p , and robot ( green ) , r , at input frequency = 0.6 hz . ( b ) \n pyramidal lucas kanade method ( 3 pyramid levels ) is used to compute the optic flow field between successive image frames . \n horizontal angular velocity is calculated by summing the projections of individual vectors in the flow fields onto the horizontal unit vector i. horizontal back - to - front motion that excites the h1 cell is referred to as pd ( preferred direction ) while horizontal front - to - back motion that inhibits the h1 cell is referred to as nd ( null direction ) . \n input frequencies for the turn - table signal , p , are chosen between 0.03 - 3 hz and the corresponding robot signal , r , is recorded . \n both signals are transformed into the frequency domain by a fast fourier transform ( see figure 4 ) and the amplitude and phase values are calculated at the input frequency.figure 4 : frequency response . \n angular velocity signals for the turn - table , p , and robot , r , are transformed into the frequency domain using the fast fourier transform ( fft ) method to calculate amplitude and phase components at the input frequency . \n the bode magnitude plot for the proportional controller with kp=1 shows the response of the system over the tested input frequencies ( see figure 5-a ) . \n the performance of the controller generally decreases with increasing frequencies . the slightly increased gain at 1 hz is as a result of oscillations in the robot signal due to using only one h1-cell whose dynamic ( output ) range mainly covers horizontal back - to - front motion.figure 5 : proportional controller performance . \n the bode magnitude and phase plots for the proportional controller ( averaged over 8 flies ) , static gain kp = 1.0 ( a ) the bode magnitude plot roughly follows a low pass filter characteristic . the slightly increased gain at 1 hz is as a result of oscillations in the robot signal , r , due to using only one h1-cell whose dynamic ( output ) range mainly covers horizontal back to front motion . \n the number of oscillations in the robot signal , r , decrease with increasing input frequencies leading to slightly increased gain at these frequencies . \n ( b ) the bode phase plot is less than 180 for input frequencies 1 hz and approaches instability at 3 hz . beyond a certain input frequency , \n this instability only occurs beyond the known optimal response range of the fly visual system ( warzecha et al . \n the bode phase plot ( see figure 5-b ) shows a controller phase lag less than for input frequencies < 0.6 hz . \n this shows that the controller is stable for frequencies < 0.6 hz and unstable for input frequencies 1 hz . the performance of the proportional controller with a static kp ( in blue ) was compared with an adaptive controller ( in red ) , where the value for kp is updated every 50 ms based on the peak spike rate , fmax , calculated over time interval [ t-500ms - t ] ( see figure 6 ) . as a result of the large integration time window \n , the proportional controller performs better than the adaptive controller for the parameter range tested ( see figure 7-a ) . \n the initial time integration window of 500 ms was chosen for technical reasons related to the robot platform we are using . \n the adaptive controller had a similar phase characteristic as the proportional controller ( see figure 7-b ) . \n the proportional controller uses a static gain , kp , whereas the adaptive controller estimates the gain continuously during closed loop control . \n the dynamic gain , kp , is inversely proportional to the maximum spike rate , fmax , over the interval t-500ms t. figure shows three instances where fmax is estimated over time . \n based on estimated values of fmax , kp is highest during time window 2 ( green ) and lowest during time window 3 ( orange ) . \n bode magnitude and phase plots for the proportional ( kp = 1 ) and adaptive controller ( a ) the adaptive controller updates the value of kp every 50ms based on the peak spike rate estimate fmax over the last 500ms . \n the proportional controller gain plot ( blue ) is higher than that of the adaptive controller ( red ) indicating that it is performing better at all input frequencies . \n ( b ) the bode phase plots for both controllers are similar with a significant difference at f = 0.3 hz . both controllers approach instability at 3 hz . significantly different gain and phase values \n are indicated by an asterix ( wilcoxon rank sum method , p = 0.05 ) . \n the grating pattern around the turntable was removed and the lab environment was used as an approximation of naturalistic visual input for the fly h1-cell . on average \n , the bode magnitude plot ( see figure 8-a ) for the naturalistic visual input ( in blue ) showed slightly higher gains than the one with grating visual input ( in red ) probably because the wider range of spatial frequencies in naturalistic visual images is exploited . \n the bode phase plot characteristics for grating vs naturalistic visual inputs were similar ( see figure 8-b).figure 8 : stripped pattern vs. lab environment . \n the bode magnitude and phase plots for the proportional controller when presented with stripped patterns ( red ) vs lab environment ( blue ) visual images under closed loop ( a ) the bode magnitude plot for when lab environment images are used is marginally higher than when stripped pattern is used ( except at f = 0.1 hz ) indicating better performance under such stimulus . \n ( b ) the bode phase plot under both visual conditions follow the same pattern , with both approaching instability at 3 hz . significantly different gain and phase values \n are indicated by an asterix ( wilcoxon rank sum method , p = 0.05 ) . \n fly dissection needs to be carried out carefully making sure that we correctly orient the fly with respect to the computer monitors . separating the spikes from the h1 neuron from the spikes from all other neurons to get a good signal to noise ratio which can then be used to control the robot reliably . \n care should be taken to prevent any neural tissue from drying out during the course of the experiment . \n care should be taken so that they are not over - wound during the experiment as that would affect the rotation of the robot . \n currently we are using the spike activity of one h1 to setup a stabilization task in only one direction of yaw rotation . \n we can add a second electrode to get signals from both left and right h1 's so that we can study stabilization control algorithms in both directions of yaw rotation . \n we can remove the arena containing the vertically oriented black and white stripes and use the lab environment as the visual stimulus for the fly . \n the robot can be removed from the turn - table and allowed to move around the lab environment while in closed - loop control . \n the wires connecting the cameras to the computers can be removed by implementing a wireless transmission system , giving us a completely unrestrained robotic setup . \n the performance measures of the different control algorithms will give us an understanding of how different strategies are able to cope with non - stationary and variable neuronal signals . \n this knowledge can then be applied to different clinical and non - clinical brain - machine interfaces . \n our goal is to place the fly on the robot and use its neural activity for closed - loop control . \n in such a setup , we would be able to record neural activity from the fly while it is receives multisensory stimulation as a result of the motion of the robot . \n you , the most suitable cell would be the h1-cell . isolating the responses of the h1 neuron from other neurons with similar receptive fields , \n e.g. h2 , is important to maintain a good signal to noise ratio for the neuronal recordings . \n the responses of the h1 and h2 neurons can be discriminated by noting that the h2 has characteristically lower spontaneous and mean spiking rate than the h1 neuron . \n the neurons can also be discriminated on the basis of their morphology ( krapp et al . \n our system allows us to compare the closed - loop gain achieved by our fly - robot interface on an image stabilization task , and to compare its performance with closed - loop optomotor gains observed in previous experiments on flies ( bender & dickinson 2006 , warzecha et al . \n additionally , it allows us to investigate state - dependant changes in visual information processing under closed - loop conditions ( chiappe et al .", "role": "user" }, { "content": "the non - stationary nature and variability of neuronal signals is a fundamental problem in brain - machine interfacing . \n we developed a brain - machine interface to assess the robustness of different control - laws applied to a closed - loop image stabilization task . \n taking advantage of the well - characterized fly visuomotor pathway we record the electrical activity from an identified , motion - sensitive neuron , h1 , to control the yaw rotation of a two - wheeled robot . the robot is equipped with 2 high - speed video cameras providing visual motion input to a fly placed in front of 2 crt computer monitors . \n the activity of the h1 neuron indicates the direction and relative speed of the robot 's rotation . \n the neural activity is filtered and fed back into the steering system of the robot by means of proportional and proportional / adaptive control . \n our goal is to test and optimize the performance of various control laws under closed - loop conditions for a broader application also in other brain machine interfaces .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: hypernatremia caused by the disruption of water homeostasis is a commonly encountered electrolyte disorder , it frequently develops into serious complications such as hemorrhage , thrombosis and cerebral edema resulting not from the hypernatremia itself but from its inappropriate rate of sodium correction123 ) . because impairment of thirst or limited access to water is the main cause of sustained hypernatremia \n , excessive intake of salt causing severe hypernatremia is rarely diagnosed in healthy , young adults4 ) . here , we have described a case of hypernatremia that developed due to exogenous intake of salt accompanied by primary hypothyroidism , which was successfully treated by intravenously infused hypotonic and hypertonic saline to allow gradual correction of serum sodium ; abrupt change of sodium level was occurred nevertheless ; without the occurrence of any neurological sequelae . \n a 26-year - old man diagnosed with crohn 's disease ( cd ) 5 years previously was admitted to our clinic for generalized edema , sudden weight gain , 10 kg over 2 weeks , reaching to 59 kg and personality changes with aggressive behavior . \n reportedly , he had muttered something to himself and then suffered loss of bowel control 4 hour before presentation . \n the patient was abnormally obsessed with ingestion of salt voluntarily for the past 4 days , based on mistaken information that salt consumption could relieve generalized edema . \n the total consumption was estimated to be approximately 154 g of sun - dried salt . \n on arrival to our emergency department , the patient was afebrile with a blood pressure of 90/60 mmhg , respiratory rate of 16 , heart rate of 87 , and the neurological examination was unremarkable . \n initial laboratory tests yielded the following results : serum sodium , 188.1 mmol / l ( normal , 138148 mmol / l ) ; potassium , 3.32 mmol / l(normal , 3.55.3 mmol / l ) ; chloride , 160.9 mmol / l(normal , 100110 mmol / l ) ; bicarbonate , 23.7 mmol / l ( normal , 2028 mmol / l ) ; anion gap , 3.5 ; calculated serum osmolality , 380 mosm / kg ( normal , 275300 mosm / kg ) ; urine osmolality , 817 mosm / kg ( normal , 300800 mosm / kg ) ; osmolar gap , 5 mosm / kg ; total protein , 3.4 g / dl(normal , 6.08.0 g / dl ) ; and albumin 1.5 g / dl ( normal , 3.35.2 g / dl ) . \n hypernatremia caused by salt intoxication was diagnosed and we set up the maximal rate of correction of sodium concentration of 10 mmol / l / day due to the ambiguous duration of the hypernatremia , using 5% dextrose as the hypotonic fluid administered at the rate of 150 ml / hour . \n the urine output of the patient was maintained at approximately 30 ml / hour . within 3 hours , a decrease of approximately 4 mmol / l in the serum sodium level \n was noted ( 184.8 mmol / l ) and the infusion rate was adjusted to 40 ml / hour ( fig . \n later , the serum sodium level had decreased sharply to 175.1 mmol / l and we stopped the administration of the hypotonic fluid . although we discontinued the fluid therapy , the serum sodium level decreased by 30 mmol / l , within 24 hours , reaching 157.4 mmol / l . \n therefore , we restarted an infusion of 3% saline and the serum sodium level stabilized around 157.5 to 159.4 mmol / l for 16 hours . \n then , the infusion rate of 3% saline was reduced from 100 ml / hour to 50 ml / hour with concomitant addition of 0.9% saline at 50 ml / hour ( fig . \n approximately 6 hours later , we stopped the administration of 3% and 0.9% saline and administered 20 mg of furosemide to control the generalized edema . at this point , \n the patient had gained 5 kg in weight , weighing 64 kg . at 6 hours after cessation of saline infusion , the serum sodium level decreased from 154.9 to 151.4 mmol / l . however , the patient became hypotensive ( 70/40 mmhg ) and required an infusion of 0.9% saline ( 100 ml / hour ) . despite restarting the 0.9% saline infusion , \n the serum sodium level decreased continually and reached 149.7 mmol / l at 3 hours later . \n after 72-hour of hospitalization , his sodium concentration had returned to normal level ( 147.5 mmol / l ) through treatment with hypertonic and isotonic saline infusion ( fig . \n thyroid function test was performed , revealing primary hypothyroidism(free t4 0.691 ng / dl , tsh 10.50 iu / ml , and t3 73.76 ng / dl ) . \n he was discharged after 9 days from admission , with a stable serum sodium level of 143.0 mmol / l . \n the patient was prescribed 50 g of levothyroxine daily and his sodium level stays within the normal range after discharge ( 139.5 - 142.3 mmol / l ) . \n inappropriate correction of hypernatremia with a rapid fall in serum sodium levels is associated with a high fatality rate5 ) . \n the rate adopted for lowering the serum sodium concentration depends on the rapidity of development of hypernatremia . \n a differentiation between acute and chronic hypernatremia can be made if the rise in serum sodium has a documented onset within the last 48 hours6 ) . in general , individuals with hypernatremia \n should be managed such that the reduction rate of serum sodium is approximately 0.5 mmol / l / day , not exceeding 10 mmol / l / day78 ) . however , in patients with hypernatremia that has developed over a period of hours , rapid correction ( 1 mmol / l / hour ) improves the prognosis without increasing the risk of cerebral edema because accumulated electrolytes are rapidly extruded from brain cells910 ) . in patients with hypernatremia of longer or unknown duration , a slower pace of correction is prudent , because the full dissipation of accumulated brain solutes occurs over a period of several days1011 ) . however , in the present case , the abrupt reduction in the serum sodium concentration did not cause any neurological problems . \n although the duration of the salt ingestion was over 48 hours , we assumed that the hypernatremia in this case was a relatively acute event considering the abrupt behavioral changes that are considered as symptoms of hypernatremia , therefore a sudden correction of the sodium level in acute hypernatremia would not lead to fatal problems . \n our case report raises the question whether the established classification of hypernatremia , distinguishing between acute and chronic hypernatremia based on the 48 hour , should be an absolute standard when deciding the correction rate and its adjustment . \n indeed , no prospective studies have validated the recommendations for the correction rates in acute and chronic hypernatremia12 ) . \n another potential explanation was that the primary hypothyroidism , which led to the impairment of water secretion as well as an increase of urinary sodium excretion , disturbed the expected rate of correction . \n the thyroid hormone affects renal hemodynamics , the renin - angiotensin - aldosterone system and renal electrolyte handling13 ) . \n there is a proven association between hypothyroidism and hyponatremia as a consequence of inability to excrete free water load , caused by both a decrease in the delivery of water to the distal nephron14 ) and enhanced renal water retention mediated by excess vasopressin secretion . \n however , little is known regarding the effect of hypothyroidism on the rate of sodium correction in the treatment of hypernatremic patients . additionally , \n considering cd - associated mucosal inflammation may cause hyponatremia due to reversal of sodium - water flux in colonic epithelium15 ) , cd may not lead to aggravation of hypernatremia in our case . \n it has been known that the estimated fatal amount is 1 g sodium chloride per kg body weight16 ) , leading to a rise in blood sodium concentration of about 30 mmol / l . in literature , \n all dead patients represented a short period of salt ingestion , even a few minutes . otherwise , the surviving patients had a relatively longer duration of sodium exposure than non - surviving cases , with considerably different sodium concentrations , though1718 ) . \n in surviving cases , addleman et al.17 ) reported a longer period of salt intake than those reported by ellis et al.18 ) , several days and 11 hours , respectively ( table 1 ) . \n . showed an abrupt decrease in the serum sodium level , from an initial value of 193 \n mmol / l to the normal range within 72 hours , with no neurological sequelae similar to the course of recovery in our case . \n our case can be differentiated from previous cases of hypernatremia over a longer duration and successful survival despite aggressive hypotonic fluid replacement4 ) . to our knowledge , this is the first case a of patient with cd and newly diagnosed primary hypothyroidism with severe symptomatic hypernatremia due to exogenous salt intoxication , successfully treated without sustained hypotonic fluid therapy along with infusion of hypertonic saline . \n we suggest that the existing standards for hypernatremia , classified as acute and chronic based on 48 hour onset6 ) , require revision . a novel approach for the", "role": "user" }, { "content": "this report describes a case of severe hypernatremia with a serum sodium concentration of 188.1mmol / l caused by exogenous salt intake . a 26-year - old man diagnosed with crohn 's disease 5 years previously visited our clinic due to generalized edema and personality changes , with aggressive behavior . \n he had compulsively consumed salts , ingesting approximately 154 g of salt over the last 4 days . despite careful fluid management that included not only hypotonic fluid therapy for 8 hours but also hypertonic saline administration , \n his serum sodium level decreased sharply at 40.6 mmol / l ; however , it returned to normal within 72-hour of treatment without any neurological deficits . \n primary hypothyroidism was also diagnosed . \n he was discharged after 9 days from admission , with a stable serum sodium level . \n we have described the possibility of successful treatment in a patient with hypernatremia caused by acute salt intoxication without sustained hypotonic fluid therapy .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: an 83-year - old male suffering from severe symptomatic aortic valve stenosis and , being a high surgical risk , received an implant of a biological aortic prosthesis ( corevalve 29 ) through the femoral artery . during the evaluation \n 1a ) showed sinus rhythm with an incomplete right - bundle branch block and left anterior hemiblock . \n the echocardiogram showed signs of calcifications in the aortic valve with a peak gradient of 90 mmhg and a medium gradient of 60 mmhg . \n the left ventricle showed good global and segmental contraction and the coronography showed insignificant irregular coronary vessels . during the expansion process of the prosthetic valve in the aortic root , we observed a previously unregistered complete heart block , which lasted for 23 min . \n 1b ) showed how atrioventricular conduction immediately restarted after the complete block , with a slight widening of the qrs . \n the patient was hospitalized and monitored for seven days , without presenting any further heart block or arrhythmia . \n when arriving at the emergency room , the vital signs were normal and the ecg was similar to the one taken at the time of discharge . \n fortunately , the patient was wearing an ecg holter monitor that day , which revealed a wide qrs complex tachycardia of 300 beats per minute ( bpm ) lasting 43 min ( fig . \n an electrophysiological study was performed , which revealed an hv interval of 64 ms . \n we induced , through ventricular stimulation , a 300 bpm ventricular tachycardia ( fig . \n 2a ) with a left - bundled branch block and left axis , with similar morphology to the syncope - registered ecg . \n the post pacing interval after entrainment by right ventricular apex stimulation was + 20 ms ( fig . \n the conclusion was that the cause of the syncope was due to a bundle - branch reentry . \n radio - frequency was applied on the right - bundle branch , with a qrs widening from 130 ms to 150 ms ( fig . \n the hv interval after the ablation was of 67 ms , and the wenckebach av point was 180 bpm . \n the insertion of metallic materials close to the prosthetic overlays , in particular within the first millimeters of the interventricular septum under the aortic root , can harm the conduction system . \n approximately 45% of the patients with a corevalve prosthesis develop signs of a left - bundle branch block . \n only 510% of the patients develop a right - bundle branch block , as seen in our patient . \n lastly , approximately 2530% of the patients with a core valve prosthesis need a pacemaker implantation . \n furthermore , it is also known that aortic valve diseases , valve surgery and conduction impairments may cause bundle - branch reentry tachycardia . \n bundle - branch reentry tachycardia is a macroreentrant tachycardia that uses the right and left branches as reentry components in its circuit . \n non - ischemic dilated myocardiopathies , bundle - branch reentry tachycardia may amount to 40% of the induced ventricular tachycardias . \n it has also been noted that aortic valve surgery may trigger bundle - branch reentry tachycardia . \n bundle - branch reentry tachycardia may be seen at an early stage , normally four weeks after surgery and the ventricular function tends to be regular . \n ventricular tachycardias that set at a later stage are usually related to periannular scars or underlying myocardiopathies . as far as we are aware , this is the first case of a bundle - branch reentry tachycardia after trans - catheter implantation of a prosthetic aortic valve . if our patient had not been wearing the ecg holter at the time of the syncope , we would have not been able to register the tachycardia and would have implanted a pacemaker . especially , taking into account the paroxysmal complete block that the patient experienced during the implant of the valve and the widening of the qrs . \n with regard to the electrophysiological study , we wish to outline the utility of the return cycle for the diagnosis of the bundle - branch reentry tachycardia in patients with difficulties at the his registry . \n we believe that the implantation of a pacemaker is not required at the onset of syncope in patients who have undergone a trans - catheter implantation of an aortic valve , and developed a bundle - branch block . in these cases , \n an electrophysiological study is suggested in order to exclude the presence of a bundle - branch reentry tachycardia . \n ", "role": "user" }, { "content": "an 83-year - old male suffering from severe symptomatic aortic valve stenosis received an implant of a biological aortic prosthesis through the femoral artery without complications . \n seven days after dischargement he experienced a syncope . \n the patient was wearing an ecg holter monitor that day , which showed a wide qrs complex tachycardia of 300 beats per minute . \n the electrophysiological study revealed a bundle - branch reentry ventricular tachycardia as the cause of the syncope . \n radio - frequency was applied on the right - bundle branch . \n twelve months later , the patient has remained asymptomatic .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: comorbidity is conceptualized differently depending on whether the perspective is clinical , epidemiologic , or health policy based . \n traditionally , comorbidity refers to the total burden of illness other than the index disease of interest , and typically focuses on chronic conditions . \n this definition excludes complications that are a direct result of the index disease . while both comorbidity and complications may influence outcomes , their etiologies and types of interventions \n , we focus on comorbidity . for some conditions , such as immune - mediated neurologic disease \n , it may be difficult to determine whether 2 distinct conditions exist ( that is , ms and another condition ) or not ( that is , the other condition alone or ms alone ) , but such diagnostic decisions are not the focus of this article . \n we also recognize that for some conditions , such as depression or anxiety , it may be difficult to distinguish between comorbidity and complication or symptom of disease . \n however , we have chosen to consider these conditions as comorbidities rather than symptoms of ms because in some individuals they appear to occur independent of ms , such as when onset is many years before clinical onset of ms , multiple factors may contribute to depression or anxiety in ms , which may or may not be ms - related , such as genetic factors or psychosocial stressors , and they have specific diagnostic criteria , unlike symptoms such as fatigue . \n however , behaviors such as smoking and alcohol intake affect the risks of , and outcomes of , chronic diseases , including ms . \n in other diseases , such as lung cancer , health behaviors such as smoking have independent effects on outcomes . \n therefore , we considered health behaviors as a type of comorbidity rather than simple confounders when making our recommendations . \n conditions may co - occur due to chance , or be more likely to be diagnosed because of increased health system contacts due to the presence of a chronic condition . of greater interest is the co - occurrence of disease due to etiologic mechanisms such as direct causation , associated risk factors , heterogeneity , and independence . in direct causation , one condition leads directly to another condition , as observed when idiopathic thrombocytopenic purpura arises from the use of alemtuzumab to treat ms . \n smoking may underlie the increased prevalence of lung disease in ms as persons with ms smoke more than the general population . in heterogeneity \n , independent factors such as age may be associated with co - occurrence of disease . \n finally , 2 conditions may coexist because they are secondary to a third , undiagnosed disease ( independence ) . \n for example , asthma and peripheral neuropathy might both be due to churg - strauss syndrome . \n such mechanistic questions are relevant to understanding comorbidity in ms , but were not the focus of our deliberations . \n comorbidity is one of several patient characteristics , including genetics , age , sex , race , ethnicity , and socioeconomic status , which are relevant to the clinical presentation and management of ms . \n socioeconomic status appears to account for some of the disparity in disability observed between african americans and caucasian americans with ms . \n age , for example , is a critical determinant of the degree of disability experienced by persons with ms , suggesting that progressive ms represents an age - related neurodegenerative process . \n comorbidities such as hypertension , diabetes , and hyperlipidemia also increase in frequency with age , and can be conceptualized to accelerate brain aging , potentially accelerating disability progression in ms . \n research regarding comorbidity can be grouped into the following areas : the incidence and prevalence of comorbidity ; the effect of comorbidity on the affected individual , health system , and society ; the mechanisms underlying the frequency of comorbidity and its effect ; and evaluation of interventions to prevent comorbidities or to reduce their impact . \n preparatory to the workshop , we surveyed experts regarding their views of the most relevant comorbidities and health behaviors to evaluate with respect to incidence , prevalence , and their effect on ms outcomes . survey design and results are detailed in appendices e-1 and e-2 on the neurology web site at neurology.org . \n the top 3 comorbidities deemed to be in greatest need of study with respect to their effect on outcomes were psychiatric disorders , cancer , and autoimmune disease ; the top 3 health behaviors were substance use , alcohol use , and diet . \n the most important research gaps identified were comorbidity as a prognostic factor for ms outcomes , followed by estimates of the frequency of comorbidity . \n with respect to health behaviors , the most important research gaps identified were their roles as prognostic factors for ms , followed by their effect on pharmacotherapy . \n preparatory to the workshop , we reviewed the world ( english - language ) literature regarding the incidence and prevalence of comorbidity in ms . \n based on meta - analyses of population - based studies , the comorbidities with the highest incidence were hypertension ( 3.73% ; 95% confidence interval [ ci ] 3.434.06% ) , stroke ( 2.73% ; 95% ci 2.512.95% ) , and cancer ( any cancer 4.3% ; 95% ci 2.676.1 ) ; however , population - based studies were lacking for many conditions . \n the most prevalent comorbidities were depression ( 23.7% ; 95% ci 17.430.0% ) , anxiety ( 21.9% ; 95% ci 8.7635.0% ) , hypertension ( 18.6% ; 95% ci 13.923.2% ) , hyperlipidemia ( 10.9% ; 95% ci 5.616.1% ) , and chronic lung disease ( 10.0% ; 95% ci 020.9% ) . \n several comorbidities occur more often in the ms population than the general population , including depression , anxiety , bipolar disorder , alcohol abuse , stroke , ischemic heart disease , inflammatory bowel disease , irritable syndrome , seizure disorders , and sleep disorders . \n valid , reliable estimates of the incidence and prevalence of comorbidity in ms are needed to inform the design of studies assessing the impact of comorbidity , support pharmacovigilance efforts , and direct clinical programs aimed at mitigating the impact of comorbidity . however , we identified gaps in knowledge regarding the epidemiology of comorbidity in ms . \n first , most studies were conducted in few geographic regions , mainly western europe and north america . given worldwide variation in the burden of many chronic diseases , \n second , estimates of the incidence and prevalence of comorbidity varied widely , likely due to heterogeneity in study design , bias , and true differences between populations . \n common limitations included the failure to report diagnostic criteria or validation of the approach used to identify the ms population or the comorbidity , lack of information regarding the time period when the study was conducted , and lack of a population - based design . \n thus , homogeneous and more rigorous study designs are needed to clarify the true variation in incidence and prevalence of comorbidity across regions and sociodemographic groups . \n reporting of age , sex , and ethnicity - specific estimates , and standardization of findings to a common population , would also improve comparability of study findings . \n third , many potentially relevant comorbidities were infrequently evaluated . finally , although many studies evaluated the incidence and prevalence of multiple comorbidities , the relationship of these comorbidities to one another was rarely considered . with increasing age , the prevalence of comorbidity increases in ms , typically when disability is also accumulating . \n therefore , the effect of comorbidity on ms is likely to be important as ms progresses . \n preparatory to the workshop , we also systematically reviewed the association of comorbidity with outcomes commonly reported in clinical trials ( relapses , disability , functional status , cognition , mri outcomes , pain , and fatigue ; for methods , see appendix e-3 ) . \n we chose the same comorbidities as those considered in our systematic review of the incidence and prevalence of comorbidity in ms . \n we identified 35 publications from 32 unique studies ( table e-1 and appendix e-3 ) . \n most studies evaluated psychiatric comorbidities ( 17 ) or vascular comorbidities , including diabetes , hypertension , hyperlipidemia , ischemic heart disease , and peripheral vascular disease ( 6 ) . \n depression , anxiety , and sleep disorders are consistently associated with the presence and severity of fatigue . \n depression is also associated with impaired cognitive function , but not relapses or disability . the presence of physical comorbidities is associated with greater disability at the time of ms diagnosis ; the effect increased with an increasing number of comorbidities . \n serum lipid measurements not necessarily meeting criteria for dyslipidemia have been associated with new hyperintense and contrast - enhancing lesions on mri , and with disability progression , but not with relapses . \n however , most potentially relevant comorbidities have not been studied and we identified few population - based studies . \n definitions of comorbidities differed across studies , and most studies did not consider the potential confounding effects of treatment of the comorbidities on outcome . \n many studies were cross - sectional , precluding causal inferences . finally , it was often unclear if outcomes were assessed blind to comorbidity status . \n future studies should be longitudinal , and need to enroll representative populations , use validated methods to assess comorbidity status and outcome , and assess potential confounding factors . \n nearly 50% of persons with ms report ever smoking before ms symptom onset , and up to 39% actively smoke at the time of ms symptom onset . \n the prevalence of definite or probable alcohol abuse or dependence ranges from 3.96% to 18.2% . \n excessive weight and obesity are highly prevalent in the ms population , affecting nearly 50% of individuals . \n although some inconsistencies exist , smoking appears to be associated with more rapid disability progression , accumulation of hyperintense lesions on mri , and greater brain atrophy . in a cross - sectional study of 423 persons with ms , those who consumed alcohol for 15 years or less after ms onset had lower disability on the expanded disability status scale ( edss ) and higher brain volume than those who did not consume alcohol or who consumed it for more than 15 years . in a belgian study of 1,372 persons with ms , \n moderate alcohol consumption was associated with a reduced risk of progression to an edss score of 6.0 ( cane ) . in the north american research committee on multiple sclerosis ( narcoms ) cohort , \n obesity was associated with an increased likelihood of presenting with a relapsing , rather than progressive , course at onset among women , independent of age . in a cohort of australians , body mass index \n an important limitation is that most of these studies considered the effect of only one health behavior on outcome , and did not consider the confounding effects of comorbidity . \n future observational studies would benefit from considering the effects of comorbidities and health behaviors concurrently , and should attempt to disentangle the direction of causation between comorbidity and ms outcomes . \n another important unknown is whether there are interactions among co - occurring comorbidities and health behaviors leading to additive or synergistic effects on outcomes . \n metabolic syndrome , for example , is diagnosed when any 3 of the following are present : abdominal obesity , hypertension , elevated fasting glucose , high serum triglycerides , and low high - density lipoprotein level . \n it is also unknown whether the timing of the development of a comorbidity , its severity , or its treatments are relevant to its effects . \n preparatory to the workshop , we reviewed the world ( english - language ) literature regarding the incidence and prevalence of comorbidity in ms . \n based on meta - analyses of population - based studies , the comorbidities with the highest incidence were hypertension ( 3.73% ; 95% confidence interval [ ci ] 3.434.06% ) , stroke ( 2.73% ; 95% ci 2.512.95% ) , and cancer ( any cancer 4.3% ; 95% ci 2.676.1 ) ; however , population - based studies were lacking for many conditions . \n the most prevalent comorbidities were depression ( 23.7% ; 95% ci 17.430.0% ) , anxiety ( 21.9% ; 95% ci 8.7635.0% ) , hypertension ( 18.6% ; 95% ci 13.923.2% ) , hyperlipidemia ( 10.9% ; 95% ci 5.616.1% ) , and chronic lung disease ( 10.0% ; 95% ci 020.9% ) . \n several comorbidities occur more often in the ms population than the general population , including depression , anxiety , bipolar disorder , alcohol abuse , stroke , ischemic heart disease , inflammatory bowel disease , irritable syndrome , seizure disorders , and sleep disorders . \n valid , reliable estimates of the incidence and prevalence of comorbidity in ms are needed to inform the design of studies assessing the impact of comorbidity , support pharmacovigilance efforts , and direct clinical programs aimed at mitigating the impact of comorbidity . however , we identified gaps in knowledge regarding the epidemiology of comorbidity in ms . \n first , most studies were conducted in few geographic regions , mainly western europe and north america . given worldwide variation in the burden of many chronic diseases , \n second , estimates of the incidence and prevalence of comorbidity varied widely , likely due to heterogeneity in study design , bias , and true differences between populations . \n common limitations included the failure to report diagnostic criteria or validation of the approach used to identify the ms population or the comorbidity , lack of information regarding the time period when the study was conducted , and lack of a population - based design . \n thus , homogeneous and more rigorous study designs are needed to clarify the true variation in incidence and prevalence of comorbidity across regions and sociodemographic groups . \n reporting of age , sex , and ethnicity - specific estimates , and standardization of findings to a common population , would also improve comparability of study findings . \n third , many potentially relevant comorbidities were infrequently evaluated . finally , although many studies evaluated the incidence and prevalence of multiple comorbidities , the relationship of these comorbidities to one another was rarely considered . with increasing age , the prevalence of comorbidity increases in ms , typically when disability is also accumulating . \n therefore , the effect of comorbidity on ms is likely to be important as ms progresses . \n preparatory to the workshop , we also systematically reviewed the association of comorbidity with outcomes commonly reported in clinical trials ( relapses , disability , functional status , cognition , mri outcomes , pain , and fatigue ; for methods , see appendix e-3 ) . \n we chose the same comorbidities as those considered in our systematic review of the incidence and prevalence of comorbidity in ms . \n we identified 35 publications from 32 unique studies ( table e-1 and appendix e-3 ) . \n most studies evaluated psychiatric comorbidities ( 17 ) or vascular comorbidities , including diabetes , hypertension , hyperlipidemia , ischemic heart disease , and peripheral vascular disease ( 6 ) . \n depression , anxiety , and sleep disorders are consistently associated with the presence and severity of fatigue . \n the presence of physical comorbidities is associated with greater disability at the time of ms diagnosis ; the effect increased with an increasing number of comorbidities . \n serum lipid measurements not necessarily meeting criteria for dyslipidemia have been associated with new hyperintense and contrast - enhancing lesions on mri , and with disability progression , but not with relapses . \n however , most potentially relevant comorbidities have not been studied and we identified few population - based studies . \n definitions of comorbidities differed across studies , and most studies did not consider the potential confounding effects of treatment of the comorbidities on outcome . \n many studies were cross - sectional , precluding causal inferences . finally , it was often unclear if outcomes were assessed blind to comorbidity status . \n future studies should be longitudinal , and need to enroll representative populations , use validated methods to assess comorbidity status and outcome , and assess potential confounding factors . \n nearly 50% of persons with ms report ever smoking before ms symptom onset , and up to 39% actively smoke at the time of ms symptom onset . \n the prevalence of definite or probable alcohol abuse or dependence ranges from 3.96% to 18.2% . \n excessive weight and obesity are highly prevalent in the ms population , affecting nearly 50% of individuals . \n although some inconsistencies exist , smoking appears to be associated with more rapid disability progression , accumulation of hyperintense lesions on mri , and greater brain atrophy . in a cross - sectional study of 423 persons with ms , those who consumed alcohol for 15 years or less after ms onset had lower disability on the expanded disability status scale ( edss ) and higher brain volume than those who did not consume alcohol or who consumed it for more than 15 years . in a belgian study of 1,372 persons with ms , \n moderate alcohol consumption was associated with a reduced risk of progression to an edss score of 6.0 ( cane ) . in the north american research committee on multiple sclerosis ( narcoms ) \n cohort , obesity was associated with an increased likelihood of presenting with a relapsing , rather than progressive , course at onset among women , independent of age . in a cohort of australians , body mass index \n an important limitation is that most of these studies considered the effect of only one health behavior on outcome , and did not consider the confounding effects of comorbidity . \n future observational studies would benefit from considering the effects of comorbidities and health behaviors concurrently , and should attempt to disentangle the direction of causation between comorbidity and ms outcomes . \n another important unknown is whether there are interactions among co - occurring comorbidities and health behaviors leading to additive or synergistic effects on outcomes . \n metabolic syndrome , for example , is diagnosed when any 3 of the following are present : abdominal obesity , hypertension , elevated fasting glucose , high serum triglycerides , and low high - density lipoprotein level . \n it is also unknown whether the timing of the development of a comorbidity , its severity , or its treatments are relevant to its effects . \n preparatory to the workshop , we reviewed the world ( english - language ) literature regarding the incidence and prevalence of comorbidity in ms . \n based on meta - analyses of population - based studies , the comorbidities with the highest incidence were hypertension ( 3.73% ; 95% confidence interval [ ci ] 3.434.06% ) , stroke ( 2.73% ; 95% ci 2.512.95% ) , and cancer ( any cancer 4.3% ; 95% ci 2.676.1 ) ; however , population - based studies were lacking for many conditions . \n the most prevalent comorbidities were depression ( 23.7% ; 95% ci 17.430.0% ) , anxiety ( 21.9% ; 95% ci 8.7635.0% ) , hypertension ( 18.6% ; 95% ci 13.923.2% ) , hyperlipidemia ( 10.9% ; 95% ci 5.616.1% ) , and chronic lung disease ( 10.0% ; 95% ci 020.9% ) . \n several comorbidities occur more often in the ms population than the general population , including depression , anxiety , bipolar disorder , alcohol abuse , stroke , ischemic heart disease , inflammatory bowel disease , irritable syndrome , seizure disorders , and sleep disorders . \n valid , reliable estimates of the incidence and prevalence of comorbidity in ms are needed to inform the design of studies assessing the impact of comorbidity , support pharmacovigilance efforts , and direct clinical programs aimed at mitigating the impact of comorbidity . however , we identified gaps in knowledge regarding the epidemiology of comorbidity in ms . \n first , most studies were conducted in few geographic regions , mainly western europe and north america . given worldwide variation in the burden of many chronic diseases , \n second , estimates of the incidence and prevalence of comorbidity varied widely , likely due to heterogeneity in study design , bias , and true differences between populations . \n common limitations included the failure to report diagnostic criteria or validation of the approach used to identify the ms population or the comorbidity , lack of information regarding the time period when the study was conducted , and lack of a population - based design . \n thus , homogeneous and more rigorous study designs are needed to clarify the true variation in incidence and prevalence of comorbidity across regions and sociodemographic groups . \n reporting of age , sex , and ethnicity - specific estimates , and standardization of findings to a common population , would also improve comparability of study findings . \n third , many potentially relevant comorbidities were infrequently evaluated . finally , although many studies evaluated the incidence and prevalence of multiple comorbidities , the relationship of these comorbidities to one another was rarely considered . \n with increasing age , the prevalence of comorbidity increases in ms , typically when disability is also accumulating . therefore , the effect of comorbidity on ms is likely to be important as ms progresses . \n preparatory to the workshop , we also systematically reviewed the association of comorbidity with outcomes commonly reported in clinical trials ( relapses , disability , functional status , cognition , mri outcomes , pain , and fatigue ; for methods , see appendix e-3 ) . \n we chose the same comorbidities as those considered in our systematic review of the incidence and prevalence of comorbidity in ms . \n we identified 35 publications from 32 unique studies ( table e-1 and appendix e-3 ) . \n most studies evaluated psychiatric comorbidities ( 17 ) or vascular comorbidities , including diabetes , hypertension , hyperlipidemia , ischemic heart disease , and peripheral vascular disease ( 6 ) . \n depression , anxiety , and sleep disorders are consistently associated with the presence and severity of fatigue . \n the presence of physical comorbidities is associated with greater disability at the time of ms diagnosis ; the effect increased with an increasing number of comorbidities . \n serum lipid measurements not necessarily meeting criteria for dyslipidemia have been associated with new hyperintense and contrast - enhancing lesions on mri , and with disability progression , but not with relapses . \n however , most potentially relevant comorbidities have not been studied and we identified few population - based studies . \n definitions of comorbidities differed across studies , and most studies did not consider the potential confounding effects of treatment of the comorbidities on outcome . \n many studies were cross - sectional , precluding causal inferences . finally , it was often unclear if outcomes were assessed blind to comorbidity status . \n future studies should be longitudinal , and need to enroll representative populations , use validated methods to assess comorbidity status and outcome , and assess potential confounding factors . \n nearly 50% of persons with ms report ever smoking before ms symptom onset , and up to 39% actively smoke at the time of ms symptom onset . \n the prevalence of definite or probable alcohol abuse or dependence ranges from 3.96% to 18.2% . \n excessive weight and obesity are highly prevalent in the ms population , affecting nearly 50% of individuals . \n although some inconsistencies exist , smoking appears to be associated with more rapid disability progression , accumulation of hyperintense lesions on mri , and greater brain atrophy . in a cross - sectional study of 423 persons with ms , those who consumed alcohol for 15 years or less after ms onset had lower disability on the expanded disability status scale ( edss ) and higher brain volume than those who did not consume alcohol or who consumed it for more than 15 years . in a belgian study of 1,372 persons with ms , \n moderate alcohol consumption was associated with a reduced risk of progression to an edss score of 6.0 ( cane ) . in the north american research committee on multiple sclerosis ( narcoms ) cohort , \n obesity was associated with an increased likelihood of presenting with a relapsing , rather than progressive , course at onset among women , independent of age . in a cohort of australians , \n body mass index was not associated with relapse risk , but was associated with greater disability . \n an important limitation is that most of these studies considered the effect of only one health behavior on outcome , and did not consider the confounding effects of comorbidity . \n future observational studies would benefit from considering the effects of comorbidities and health behaviors concurrently , and should attempt to disentangle the direction of causation between comorbidity and ms outcomes . \n another important unknown is whether there are interactions among co - occurring comorbidities and health behaviors leading to additive or synergistic effects on outcomes . \n metabolic syndrome , for example , is diagnosed when any 3 of the following are present : abdominal obesity , hypertension , elevated fasting glucose , high serum triglycerides , and low high - density lipoprotein level . \n it is also unknown whether the timing of the development of a comorbidity , its severity , or its treatments are relevant to its effects . \n potential sources of comorbidity data include self - report , medical records , and administrative databases . \n briefly , the validity and reliability of self - reported comorbidity in ms varies by condition . \n accuracy is high for chronic conditions that are well - defined , require ongoing care , or cause disability . \n self - report is less accurate for conditions where diagnostic criteria are less precise , such as arthritis , and may vary in accuracy by sociodemographic characteristics . \n the medical record offers information about comorbidity and ms , including disability status , and treatments used \n when multiple health care providers are involved , it may be difficult to access complete information . \n therefore , medical records reviews are often not feasible for large , population - based studies . depending on the data sources used to construct a clinical database \n , they may be subject to the aforementioned limitations of self - report , medical records , or both . \n administrative data are obtained from enrolment into public and commercial health insurance plans as well as through the delivery of , and reimbursement for , health care services . \n these data generally include demographic characteristics including a personal identification number , date of birth , sex , and region of residence , but race is often lacking . \n most administrative datasets capture hospital and physician encounters , including the dates of service and diagnostic and procedure codes for the service delivered . \n widespread use of icd codes may facilitate the conduct of similar comorbidity studies in multiple jurisdictions ; however , the customization of icd-10 in many countries threatens data comparability . in many jurisdictions , \n administrative claims data are population - based , accessible , and cost - effective as compared to other data sources \n . however , their validity for research must be assessed , and clinical details are lacking . \n the potential applications to comorbidity research are broad , including comorbidity surveillance , pharmacovigilance , and evaluation of the effect of comorbidity on health care utilization . \n appendix e-4 describes potentially useful datasets that include ms - relevant comorbidity and health behavior data , worldwide . \n while the validity of some of these datasets for ms research is established , further work is necessary to validate others . \n analytically , comorbidity can be classified as a count of conditions , using an index , or by considering individual comorbidities . \n a count is the simplest to obtain and is associated with outcomes such as health care utilization , but treats all comorbidities as equal . \n some indices have been developed for use in specific populations or for specific outcomes ( e.g. , mortality ) ; relative performance varies across populations and outcomes . \n none has been developed for use in ms , and existing indices may be inappropriate for ms . \n for example , the elixhauser index captures paraplegia , and other neurologic disorders ( including ms ) , potentially confounding ms severity with comorbidity . \n consideration of individual comorbidities provides more opportunity to understand interactions between comorbidities , but requires larger samples . \n analytically , comorbidity can be classified as a count of conditions , using an index , or by considering individual comorbidities . \n a count is the simplest to obtain and is associated with outcomes such as health care utilization , but treats all comorbidities as equal . \n some indices have been developed for use in specific populations or for specific outcomes ( e.g. , mortality ) ; relative performance varies across populations and outcomes . \n none has been developed for use in ms , and existing indices may be inappropriate for ms . \n for example , the elixhauser index captures paraplegia , and other neurologic disorders ( including ms ) , potentially confounding ms severity with comorbidity . \n consideration of individual comorbidities provides more opportunity to understand interactions between comorbidities , but requires larger samples . \n following presentations that reviewed the findings of the international survey , systematic reviews , and issues related to the measurement and analysis of comorbidities , we held small group sessions to reach consensus regarding recommendations for future research . recognizing that there would be challenges in studying all comorbidities in the short term , the charge to the small groups for the first and second recommendations was to prioritize 5 comorbidities , but \n these recommendations are not intended to discourage work that evaluates other comorbidities.establish age - specific , sex - specific , and ideally race / ethnicity - specific incidence and prevalence estimates for priority comorbidities in the ms population . \n based on several considerations , we prioritized 5 comorbidities for future studies of their incidence and prevalence in ms , including depression , anxiety , hypertension , diabetes , and hyperlipidemia ( table e-2 ) . first , existing literature or clinical experience suggested they were prevalent in the ms population ( depression , anxiety , hypertension , hyperlipidemia ) . \n second , little or no information was available regarding their incidence ( all ) , or regarding age- and sex - specific estimates of their incidence and prevalence ( all ) . \n third , these conditions may affect the risk of ms or differential outcomes in ms , and are potentially treatable ( all ) . \n given the existence of some population - based data regarding the incidence of autoimmune disease and the low prevalence of many autoimmune diseases in ms , these conditions were given a lower priority.evaluate the effect of priority comorbidities on ms outcomes that are relevant from the perspective of the clinician , affected individual , health system , and society . \n due to difficulties reaching consensus regarding the top 5 comorbidities , we prioritized 7 comorbidities for observational studies of the effect of comorbidity on ms outcomes , including depression , anxiety , hypertension , diabetes , hyperlipidemia , chronic lung disease , and autoimmune diseases . when selecting these comorbidities , physiologic and biological relevance to ms , existing knowledge regarding their effects on outcomes in ms , and their prevalence in the ms population \n given its low prevalence , cancer was not prioritized , but was considered highly relevant for clinical trials . \n smoking , obesity , and physical activity were also considered priorities for both types of studies . however , future investigations should not be limited to these conditions . \n preferred outcomes are summarized in table e-2.include potential confounders or effect modifiers as covariates in studies of the effect of comorbidity on ms outcomes . \n key covariates include age , sex , race / ethnicity , socioeconomic status , and disease duration.design observational studies that have strong methodologic features . given the methodologic limitations of the existing literature , we emphasized the importance of sound study design . \n we recognized that multiple data sources could be used to address these questions , but the validity of the methods used to assess comorbidity and the outcomes of interest are critical , along with inclusion of a representative study population . \n specific efforts are needed to develop an ms - specific comorbidity index.harmonize measurement of key data elements such as sex , race / ethnicity , clinical course , comorbidity , and ms diagnostic criteria , and use common outcome measures to facilitate pooling and comparison of study findings . \n such approaches are supported by the national institute of neurological disorders and stroke common data elements project.follow published guidelines when reporting study findings . \n to be useful , observational studies need to be methodologically sound and be reported well . \n reporting guidelines aim to improve the quality of reporting in observational studies , which is often poor , as is also true in the ms comorbidity literature . \n the strengthening the reporting of observational studies in epidemiology statement provides guidelines for observational studies in general , while the standards of reporting of neurologic disorders checklist provides guidelines for reporting incidence and prevalence studies in neurologic disease.conduct observational studies of comorbidity in ms in all world regions . \n since much of the comorbidity literature has arisen from few world regions and heterogeneity in ms outcomes is well - recognized , it is critical that investigators in areas beyond western europe and north america be supported to conduct studies in their regions.explore the mechanisms of the effects of comorbidity on ms as a means of identifying potential approaches to mitigating their impact . \n this will require considering direct biological effects such as accelerated neurodegeneration ( as might be assessed using measures of brain atrophy ) or enhanced peripheral immune activation ( as might be assessed by measuring cytokine profiles or immune cell behavior ) , and indirect effects such as diagnostic delays or differences in ms treatment or treatment responses.conduct clinical trials of the effect of comorbidity treatment on ms . in other diseases , there are comorbidity - based differences in disease management . for example , hypertension targets are lower in diabetic patients than in patients without diabetes to reduce the risk of diabetes - associated complications . \n observational studies of the incidence and prevalence of comorbidity and of the effect of comorbidity on outcomes in ms are needed to inform the design of these trials . \n establish age - specific , sex - specific , and ideally race / ethnicity - specific incidence and prevalence estimates for priority comorbidities in the ms population . \n based on several considerations , we prioritized 5 comorbidities for future studies of their incidence and prevalence in ms , including depression , anxiety , hypertension , diabetes , and hyperlipidemia ( table e-2 ) . first , \n existing literature or clinical experience suggested they were prevalent in the ms population ( depression , anxiety , hypertension , hyperlipidemia ) . \n second , little or no information was available regarding their incidence ( all ) , or regarding age- and sex - specific estimates of their incidence and prevalence ( all ) . \n third , these conditions may affect the risk of ms or differential outcomes in ms , and are potentially treatable ( all ) . \n given the existence of some population - based data regarding the incidence of autoimmune disease and the low prevalence of many autoimmune diseases in ms , these conditions were given a lower priority . \n evaluate the effect of priority comorbidities on ms outcomes that are relevant from the perspective of the clinician , affected individual , health system , and society . due to difficulties reaching consensus regarding the top 5 comorbidities , we prioritized 7 comorbidities for observational studies of the effect of comorbidity on ms outcomes , including depression , anxiety , hypertension , diabetes , hyperlipidemia , chronic lung disease , and autoimmune diseases . when selecting these comorbidities , physiologic and biological relevance to ms , existing knowledge regarding their effects on outcomes in ms , and their prevalence in the ms population \n given its low prevalence , cancer was not prioritized , but was considered highly relevant for clinical trials . \n smoking , obesity , and physical activity were also considered priorities for both types of studies . however , future investigations should not be limited to these conditions \n include potential confounders or effect modifiers as covariates in studies of the effect of comorbidity on ms outcomes . \n key covariates include age , sex , race / ethnicity , socioeconomic status , and disease duration . design observational studies that have strong methodologic features . given the methodologic limitations of the existing literature , we emphasized the importance of sound study design . \n we recognized that multiple data sources could be used to address these questions , but the validity of the methods used to assess comorbidity and the outcomes of interest are critical , along with inclusion of a representative study population . \n harmonize measurement of key data elements such as sex , race / ethnicity , clinical course , comorbidity , and ms diagnostic criteria , and use common outcome measures to facilitate pooling and comparison of study findings . \n such approaches are supported by the national institute of neurological disorders and stroke common data elements project . \n reporting guidelines aim to improve the quality of reporting in observational studies , which is often poor , as is also true in the ms comorbidity literature . \n the strengthening the reporting of observational studies in epidemiology statement provides guidelines for observational studies in general , while the standards of reporting of neurologic disorders checklist provides guidelines for reporting incidence and prevalence studies in neurologic disease . \n conduct observational studies of comorbidity in ms in all world regions . since much of the comorbidity literature has arisen from few world regions and heterogeneity in ms outcomes is well - recognized , it is critical that investigators in areas beyond western europe and north america be supported to conduct studies in their regions . explore the mechanisms of the effects of comorbidity on ms as a means of identifying potential approaches to mitigating their impact . \n this will require considering direct biological effects such as accelerated neurodegeneration ( as might be assessed using measures of brain atrophy ) or enhanced peripheral immune activation ( as might be assessed by measuring cytokine profiles or immune cell behavior ) , and indirect effects such as diagnostic delays or differences in ms treatment or treatment responses . \n in other diseases , there are comorbidity - based differences in disease management . for example , hypertension targets are lower in diabetic patients than in patients without diabetes to reduce the risk of diabetes - associated complications . \n observational studies of the incidence and prevalence of comorbidity and of the effect of comorbidity on outcomes in ms are needed to inform the design of these trials . \n \n the corresponding author ( r.a.m . ) takes responsibility for the integrity of the data and the accuracy of the data analysis . \n funded in part by the national multiple sclerosis society , ectrims , a don paty career development award from the ms society of canada ( to r.a.m . ) , and a manitoba research chair from research manitoba ( to r.a.m . ) . \n the funding sources had no role in the study design , collection , analysis , or interpretation of the data , or in the decision to submit the article for publication . \n the international workshop on comorbidity in multiple sclerosis was organized under the auspices of the international advisory committee on clinical trials in multiple sclerosis . the conference and the activities of the committee \n were funded by the european committee for treatment and research in multiple sclerosis and the us national multiple sclerosis society . \n marrie receives research funding from the canadian institutes of health research , public health agency of canada , manitoba health research council , health sciences centre foundation , multiple sclerosis society of canada , multiple sclerosis scientific foundation , and rx & d health research foundation ; and has conducted clinical trials funded by sanofi - aventis . \n a. miller has received research support from novartis , genentech , genzyme , sanofi - aventis , biogen idec , roche , and mallinckrodt ( questcor ) ; personal consulting fees from genzyme / sanofi - aventis , biogen idec , glaxo smith kline , emd serono ( merck serono ) , mallinckrodt , novartis , acorda , accordant health services , teva , roche , alkermes , genentech , and caremark ( accordant health care ) ; and speaker honoraria from biogen idec ( unbranded disease awareness programs only ) . \n m. sormani received consultation fees from biogen , novartis , merck serono , teva , genzyme , roche , and synthon . \n a. thompson has received honoraria / support for travel for consultancy from biogen idec , medday , eisai , and novartis , and for teaching from excemed , novartis , and teva . \n he receives an honorarium from sage publications as editor - in - chief of multiple sclerosis journal . \n e. waubant receives research funding from the nih , the nmss , and the race to erase ms . \n she has received honorarium or travel support from actrims , ectrims , and the aan . \n m. trojano has served on scientific advisory boards for biogen idec , novartis , and genzyme ; has received speaker honoraria from biogen - idec , sanofi aventis , merck - serono , teva , novartis , and almirall ; and has received research grants for her institution from biogen - idec , merck - serono , and novartis . \n p. o'connor , k. fiest , and n. reider report no disclosures relevant to the manuscript . \n s. reingold reports personal consulting fees from the national multiple sclerosis society ( nmss ) and the european committee for treatment and research in multiple sclerosis ( ectrims ) during the conduct of this work ; and personal consulting fees from bayer healthcare , biogen idec , coronado biosciences inc . , the cleveland clinic foundation , eli lilly & company , emd serono , merck serono , genentech , f. hoffmann - laroche , ironwood pharmaceuticals inc . , \n , novartis pharmaceuticals corporation , observatoire franais de la sclrosis en plaques , opexa therapeutics , sanofi - aventis , sk biopharmaceuticals , synthon pharmaceuticals inc . , \n teva pharmaceutical industries , and fondation pour l'aide la recherche sur la sclrosis en plaques , for activities outside of this work . \n j. cohen reports personal compensation for consulting from emd serono , genentech , genzyme , innate immunotherapeutics , novartis , and vaccinex . \n cohen receives research support paid to his institution from biogen idec , consortium of ms centers , us department of defense , genzyme , us national institutes of health , national ms society , novartis , receptos , synthon , teva , and vaccinex .", "role": "user" }, { "content": "objective : to reach consensus about the most relevant comorbidities to study in multiple sclerosis ( ms ) with respect to incidence , prevalence , and effect on outcomes ; review datasets that may support studies of comorbidity in ms ; and identify ms outcomes that should be prioritized in such studies.methods:we held an international workshop to meet these objectives , informed by a systematic review of the incidence and prevalence of comorbidity in ms , and an international survey regarding research priorities for comorbidity.results:we recommend establishing age- and sex - specific incidence and prevalence estimates for 5 comorbidities ( depression , anxiety , hypertension , hyperlipidemia , and diabetes ) ; evaluating the effect of 7 comorbidities ( depression , anxiety , hypertension , diabetes , hyperlipidemia , chronic lung disease , and autoimmune diseases ) on disability , quality of life , brain atrophy and other imaging parameters , health care utilization , employment , and mortality , including age , sex , race / ethnicity , socioeconomic status , and disease duration as potential confounders ; harmonizing study designs across jurisdictions ; and conducting such studies worldwide . \n ultimately , clinical trials of treating comorbidity in ms are needed.conclusion:our recommendations will help address knowledge gaps regarding the incidence , prevalence , and effect of comorbidity on outcomes in ms .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: central nervous system plasticity that occurs in response to tissue injury may contribute to the development of persistent post - operative pain . \n many researches have focused on methods to prevent central neuroplastic changes from occurring through the utilization of pre - emptive or preventive multimodal analgesia technique . \n the original concept of preemptive analgesia put forward by crile suggested that administration of an analgesic before surgical incision might reduce the intensity of post - operative pain by reducing central sensitization . \n this definition of preemptive analgesia was thought to be too restrictive because central sensitization triggered by surgical incision continues in the intraoperative and postoperative period by noxious stimuli . \n hence , analgesic regimen covering this entire duration of stimuli may provide an effective postoperative analgesia . \n the term , preventive analgesia , was introduced to emphasize the fact that administration of a drug at any point in perioperative period may reduce post - operative pain intensity , analgesic use or both beyond the clinical duration of action of the target preventive drug . \n although many drugs have demonstrated evidence of preventive analgesic effect , drugs that prevent development of central sensitization have the greatest benefit . \n ketamine , nociceptive n - methyl d - aspartate ( nmda ) antagonist has a potential for altering central sensitization , hence we decided to use small bolus dose of ketamine followed by continuous infusion to examine preventive effect on post - operative pain and opioid consumption after open renal surgery . \n after institutional ethical committee approval and written informed consent , 60 adult patients of american society of anesthesiologists ( asa ) i and ii , 18 - 70 years of age , scheduled for open renal surgery under general anesthesia were included in this study . \n patients with chronic pain on regular medication with analgesics , psychiatric disorder and alcohol or drug abuse were excluded from the study . on the day before surgery , all the patients were made familiar with the use of 100 cm a visual analog scale ( vas ) identifying 0 as no pain and 100 the worst imaginable pain . \n patients were randomly selected by picking up a closed envelope for group c or group k. study solutions were prepared before surgery by an investigator who did not subsequently take part in the study . for bolus dose , 10 ml of normal saline was used in group c and 10 ml ketamine ( 1 mg / ml ) in group k. for infusion during maintenance , 50 ml of normal saline was prepared in group c and 50 ml of ketamine ( 1 mg / ml ) in group k. after premedication with glycopyrrolate 0.004 mg / kg , ranitidine 50 mg , metoclopromide 10 mg , and fentanyl 2 mg / kg were administered intravenous ( iv ) , anesthesia was induced with thiopental sodium 5 mg / kg and tracheal intubation was facilitated with succinylcholine 1.5 mg / kg . \n this was followed by a bolus dose of study solution 0.15 ml / kg ( ketamine 0.15 mg / kg in group k and normal saline in group c ) and continuous infusion of 0.12 ml / kg / hour ( ketamine 2 mg / kg / min in group k and normal saline for group c ) till start of skin closure . \n intraoperative vital parameters like heart rate ( hr ) , noninvasive blood pressure ( nibp ) , and oxygen saturation ( spo2 ) were monitored and any variations due to surgical stimulus ( > 20% increase in systolic blood pressure [ sbp ] and/or hr ) were controlled with change in the concentration of halothane . \n at the end of the surgery , residual paralysis was reversed with atropine 20 mg / kg and neostigmine 50 mg/ kg iv and trachea extubated when patients responded to verbal commands and head lift test was positive . \n recovery time from completion of reversal to extubation was noted . in the post anesthesia recovery room , \n another blinded observer assessed vas pain score at 15 min interval for 1st hour , then at 4 , 8 , 12 , 16 , and 24 hours after surgery . \n when vas was > 40 morphine was given as 1 mg increments until vas score was < 40 . \n time to first analgesic ( tfa - time from end of surgery to first request for morphine ) , number of patients requiring morphine and total amount of morphine given in 24 hours were recorded in both groups . \n post - operatively , the incidence of side effects like nausea , vomiting , pruritus , diplopia , sedation , emergence reaction ( dysphoria or hallucination ) , and respiratory depression ( rr < 10 breaths / min ) were noted . before the study , sample size was determined . \n based on an earlier study , we anticipated the mean morphine consumption over 24 hours to be 50 mg . to detect a difference of 30% in morphine consumption , \n estimated sample size was 28 patients per group to get a power of 90% and =0.05 . \n both study groups were comparable with respect to age , sex , type and duration of surgery , and recovery time [ table 1 ] . during the first 12 hrs after surgery , the vas pain score was significantly low in group k as compared to group c ( p<0.05 ) [ figure 1 ] . in group - k \n , only five patients required one dose of supplemental analgesic while in group c all patients required additional dose of analgesic which was statistically significant ( p<0.05 ) [ table 2 ] . \n total morphine consumption in 24 hours was significantly low in group k ( 5.8 1.46 mg ) compared to group c ( 18.1 1.6 mg ) [ table 2 ] . \n the first analgesic demand time was long in patients of group k as compared to group c [ table 2 ] which was statistically significant . \n nausea and vomiting was observed in four patients of group c and all of them were treated with ondansetron 4 mg iv . \n no side effects like sedation respiratory depression , hemodynamic disturbances , pruritus , emergence reaction , and hyperalgesia were observed in post - operative period in both the groups [ table 3 ] . \n nmda receptor noncompetitive antagonism accounts for most of its analgesic effects through a use - dependent channel blockade . \n the affinity of ketamine for nmda receptors is several - fold higher than that for receptors , non - nmda glutamate receptors , nicotinic and muscarinic cholinergic receptors , and monoaminergic transporter sites . \n pharmacological studies also suggest that addition of low - dose ketamine to opioids produces synergistic or an additive analgesic effect most likely as a result of the combination of presynaptic opioid inhibition reducing afferent transmission by diminished transmitter release and postsynaptic nmda blockade which reduces wind up and central sensitization . in recent years \n , attenuation of the development of acute tolerance to opioids by ketamine has received specific attention . \n opioids produce anti - nociception through receptor agonist activity and activation of monoaminergic descending pathways at spinal level . \n . small dose of ketamine given before noxious stimulation has an advantage of attenuating analgesic tolerance to opioids and hyperalgesia by blocking nmda receptors . \n many studies have documented a preemptive effect , but others have failed to demonstrate significant preemptive analgesic effects . in a qualitative systematic review of the role of nmda receptor antagonists in preventive analgesia , \n apart from the timing of treatment , route of administration , insufficient afferent blockade , use of opioids during surgery , intensity of noxious stimulus , and outcome measurement problems seem to be important factors responsible for lack of evidence for preemptive effects . \n optimal dosage is another controversial area . due to high affinity of ketamine for nmda receptors \n , it has been observed that smaller the dose , the more selective the ketamine interaction with nmda receptors . \n the low - dose ketamine is defined as a bolus dose of less than 2 mg / kg when given intramuscularly or less than 1 mg / kg when administered via iv or epidural route . for continuous iv administration \n , low - dose ketamine is defined as a rate of 20 g / kg / min or a serum concentration of 30 - 120 ng / ml . our dosage scheme for the ketamine infusion was calculated using published pharmacokinetic variables to achieve a plasma concentration of about 60 ng / ml which is in the small range of concentrations known to counteract hyperalgesia while producing minimal side effects . \n the initial loading bolus was 0.15 mg / kg and it was followed by a maintenance infusion of 2 g / kg / min until start of skin closure . \n similar dose of ketamine has proven to be effective after major abdominal surgery with remifentanil - based anesthesia . \n we observed that the analgesic effect of ketamine evaluated with vas , time to first analgesic , and postoperative morphine consumption , extended beyond the pharmacological actions of ketamine . \n the plasma half - life of ketamine is 17 minutes and analgesia produced by ketamine 125 and 250 g / kg iv lasts approximately five minutes when the plasma ketamine concentration is > 100 ng / ml . \n ketamine concentration in our study would be expected to be sub - analgesic with the dose used producing analgesia lasting for few minutes , however , the analgesic effect of ketamine , was clearly evident during the postoperative period ( i.e. , approximately 3.5 plasma half - lives of ketamine ) . \n infused ketamine for three days after nephrectomy and found that ketamine reduced the area of punctuate mechanical hyperalgesia surrounding the surgical incision for the seven post - operative days . with preemptive administration of ketamine , a decrease in post - operative morphine consumption was observed for two post - operative days after abdominal surgery . \n tucker et al . and zankine j et al . , showed clinical benefit of ketamine when co - administered with opioid . \n we believe that this long - lasting post - operative analgesia might be explained with a preventive analgesic effect of ketamine on central sensitization and not due to attenuation of acute tolerance to opioid because intraoperative opioids were not used in our study . \n nitrous oxide , used in the present anesthetic technique , may have enhanced nmda receptor inhibition by ketamine because nitrous oxide too has been reported to exert nmda antagonist properties . \n however , it is unlikely that nitrous oxide confounded our results as it was also present in the control group . \n as morphine consumption was lower in group k , the incidence of morphine - associated side effects , such as pruritus , nausea , and vomiting were also decreased . \n the overall incidence of adverse cns symptoms in patients receiving low - dose ketamine is approximately 10% and is dose related . \n large doses ( > 2 mg / kg , i.v . ) and rapid administration ( > 40 mg / min ) predispose to this side effect whereas they are minimal at infusion rate less than 2.5 mg / kg / min or around 200 - 300 mg/24 hrs . it is interesting to note that the highest risk is found in sedated patients who do not receive benzodiazepine , whereas in patients undergoing general anesthesia the incidence is really low and independent of benzodiazepine premedication . \n we used low dose under general anesthesia without benzodiazepine premedication and did not observe any adverse effects . \n small dose of ketamine given before skin incision and as continuous infusion throughout the surgery decreases the postoperative pain , reduces morphine consumption and delays patients request for analgesia after open renal surgery .", "role": "user" }, { "content": "background : n - methyl d - aspartate ( nmda ) receptors seem to be responsible for pain memory and their blockade can contribute significantly in prevention of pain . \n this study was conducted to evaluate the preventive effect of small dose of ketamine , a nmda receptor blocker , given before skin incision in renal surgery , with the aim to compare analgesic efficacy , intra operative and post - operative side effects.materials and methods : in a prospective double - blind study , 60 american society of anesthesiologists ( asa ) risk i and ii adult patients scheduled for elective open renal surgeries by flank incision were randomly divided in two groups . \n ketamine group ( group k ) received ketamine 0.15 mg / kg intravenously , 30 minute before start of surgery followed by infusion of ketamine 2 mcg / kg / min till start of skin closure . \n control group ( group c ) received normal saline in place of ketamine . \n both groups received morphine 0.15 mg/ kg i.v . at the time of skin closure . \n the analgesic efficacy was judged by visual analogue scale ( vas ) at rest and on movement , time to first analgesic and morphine consumption in 24 hours . \n opioid or ketamine related side effects were also recorded.results:patients in ketamine group had significantly lower vas score , longer time to first analgesic ( 21.6 0.12 vs 3.8 0.7 hrs ) , and lower morphine consumption ( 5.8 1.48 vs 18.1 1.6 mg ) in 24 hours . \n there were no demonstrable side effects related to ketamine in group k whereas incidence of nausea and vomiting was higher in group c.conclusion:our results demonstrate that small dose of ketamine decreases post - operative pain , reduces morphine consumption , and delays patients request for analgesia beyond the clinical duration of action of ketamine after open renal surgery .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: type 2 diabetes ( formerly called non - insulin - dependent or adult - onset ) results from the body 's ineffective use of insulin . \n there is an emerging global epidemic of diabetes that can be traced back to rapid increases in overweight , including obesity and physical inactivity . in 2012 \n diabetes was the direct cause of 1.5 million deaths ; more than 80% of diabetes deaths occur in low- and middle - income countries . \n the prevalence of dm is high among populations in the middle east and persian gulf countries , and patients often lack the knowledge and skills to self - manage their condition [ 46 ] . \n the prevalence of type 2 dm in iran has grown over the past decade , and the age of onset of diabetes in iran is about 10 to 15 years less than the world standard . it is therefore expected that the true prevalence of diabetes is more than what has been previously reported in iran . this high prevalence rate of diabetes is mainly due to sedentary life style , urbanization , lack of knowledge about the disease , low literacy rate , and socioeconomic status that make diabetes awareness and self - management major challenges in iran . \n dm is an important and growing health problem in both developed and developing countries as it requires life - long medical and life style adjustment . \n type 2 diabetes is the leading cause of incident and prevalent chronic kidney disease ( ckd ) , accounting for about 30% to 40% of ckd and up to 45% of end - stage renal disease ( esrd ) [ 12 , 13 ] . in the past 2 decades \n , there has been a continual increase in the incidence of esrd among patients with diabetes , predominantly those with type 2 diabetes . \n diabetes may cause acute and chronic complications if serious consideration is not taken in early stages of development . \n these complications can affect the quality of life of patients [ 16 , 17 ] and may lead to increased morbidity and mortality . \n the most common complications of diabetes have imposed high costs on both the individual and society . \n onset of complications , especially if it is combined with large and small vessel disease , can lead to reduced quality of life . prevention , pathogenesis , and mortality due to theses complications are considered major healthcare issues in the world , and that is why considerable attention has shifted to the investment for diabetes control . \n many studies have shown that control of hyperglycemia in diabetic patients can prevent or reduce the risks of diabetic complication . \n better glycemic management of dm requires not only the prescription of appropriate nutritional and pharmacological regime by the physician but also intensive education of the patient . \n large studies about this relationship have used measurements such as hba1c , lipids , kap , and self - efficacy as the index of diabetes management [ 24 , 25 ] . \n the use of self - management programs in chronic disease is relatively well known , and some of these programs are beginning to show success . \n however , there is little evidence to suggest that programs specifically for diabetic renal disease have been developed or tested . \n very few studies [ 27 , 28 ] have been conducted in iran to evaluate the level of awareness , attitudes , and practices among type 2 diabetic patients , and we found no study carried out specifically on type 2 diabetic patient receiving hemodialysis . \n therefore , this study evaluated the knowledge , attitude , and practices of diabetes patients on hemodialysis and variables that affect their kap scores . \n type 2 diabetic patients who are receiving hemodialysis in shahid beheshti academic hospitals of tehran , the capital of iran , were enrolled in the study during period of april to june 2014 . \n this study was carried out in hemodialysis wards of five academic hospitals of tehran ( shohadaye tajrish , modarres , emam hosein , and labbafi nejad ) . \n patients not interested in taking part in the study , those lacking compliance for face - to - face interview , and inpatients were excluded . by taking the lowest correlation ratio , a sample size of 113 \n an expert nurse measured systolic and diastolic blood pressure and the body mass index ( bmi ) . \n patients receiving antihypertensive medication or those with bp > 124/84 mmhg were considered as hypertensive . \n known cases of dyslipidemia ( high ldl - cholesterol , low hdl - cholesterol , and/or high triglycerides ) receiving medication were considered as dyslipidemia . \n a kap ( knowledge , attitude , and practice ) questionnaire which was locally developed and validated was used . \n this questionnaire consisted of 4 parts including demographic information , knowledge ( 10 questions ) , attitude ( 10 questions ) , and practice ( 11 questions ) . \n questions of the knowledge and practice parts were multiple choice questions with 0 - 1 and 04 scores , based on number of correct choices . \n questions of the attitude part were 2 to + 2 ( strongly agree , agree , no idea , disagree , and strongly disagree ) . the summary of diabetes self - care activities ( sdsca ) measure is a brief self - report questionnaire of diabetes self - management that includes 25 items assessing the seven aspects of the diabetes regimen : general diet , specific diet , exercise , blood glucose testing , medications , foot care , and cigarette smoking . \n response options range from 0 to 7 to correspond to the number of days in a week . \n the audit of diabetes - dependent quality of life ( addqol ) questionnaire was originally designed in 1994 and has been widely applied in many countries and is viewed as a particular and useful scale of useful diabetes - specific tool . \n each question is + 1 ( positive effect ) to 3 ( very negative effect ) scores . \n we had face - to - face interview with all the patients to fill the five questionnaires . \n data were analyzed using statistics package for social science ( spss ) v.21 for windows . \n all continuous gaussian data are expressed as mean ( sd ) and non - gaussian data as median and interquartile range ; categorical variables are expressed as no ( % ) . \n differences of continuous variables between groups were analyzed using independent t - test , anova , and tukey 's post hoc tests for gaussian data and mann - whitney for non - gaussian . \n additionally , chi - square test was used for comparison of categorical variables which were expressed as percentages . moreover \n , the correlation between variables was tested using pearson 's and spearman 's correlation considering the gaussian and non - gaussian distribution of variables , respectively . \n the ethical clearance of this study was obtained from the ethical committee of research in shahid beheshti university of medical sciences , tehran , iran . \n the details of study were explained for patients and written informed consent was obtained from all patients . \n in total , 117 diabetic patients on hemodialysis ( 42 females and 75 males ) with the age of 5088 years , mean ( sd ) 68.70 ( 9.26 ) years , and mean ( sd ) bmi of 25.07 ( 4.02 ) were enrolled in the survey . \n subjects were evenly distributed in terms of their geographical area of residence , which is important as it covers all regions of tehran with different socioeconomic levels . \n the mean ( sd ) of duration of the disease among type 2 diabetes mellitus patients on dialysis was 14.23 ( 7.29 ) years . \n 93 ( 79.5% ) subjects were treated with insulin and the others were not treated with any drugs for their diabetes . \n the results showed the average sd score of knowledge : 59.90 11.23 , for attitude : 44.27 8.35 , for practice : 45.06 12.87 , for self - care : 46.21 10.23 , and quality of life : 26.85 13.23 . \n all data are shown in appendix tables 14 ( in supplementary material available online at http://dx.doi.org/10.1155/2016/3730875 ) . \n gender , marital status , and area of residence had no statistically significant association with kap or self - care scores . \n self - care score was lower among those with disease duration of more than 10 years ( 49.8 versus 56.4 , p = 0.035 ) . \n both practice and self - care scores were higher among dialysis patients who were on insulin compared to those not on insulin ( or any other glucose - lowering treatment ) ( 46.4 versus 39.8 , p = 0.023 and 55.6 versus 33.5 , p < 0.001 , resp . ) . \n patients with a positive family history of diabetes had lower self - care scores compared to those with no family history ( 49.8 versus 59.1 , p = 0.034 ) . \n higher education level was associated with significantly higher knowledge , practice , and self - care scores , but not with improved attitude . among risk factors of disease , hypertension and smoking were associated with lower self - care scores and current smoking was associated with poor attitude . \n subjects with a positive history of diabetic foot had better practice scores compared to those with no such history , which may indicate increased awareness after the development of the complication ( table 2 ) . increased age was correlated with lower knowledge scores . \n higher knowledge score was significantly correlated with higher attitude , practice , and self - care scores and higher practice score was also significantly associated with higher self - care score . improved quality of life had a significant correlation with improved attitude ( table 3 ) . \n there was also a significant correlation between self - care 's subscales such as exercise , glucometer bs , and foot care scores with patients ' knowledge and practice levels ( table 4 ) . \n this study shows a low level of knowledge , unfavorable attitude , and moderate practice scores among our patient population of type 2 diabetes patients undergoing hemodialysis . \n we also observed a positive correlation between knowledge scores and attitude , practice , and self - care as well as attitude with quality of life and practice with self - care . \n furthermore , indices of poor glycemic control , that is , high fpg and hba1c levels , were significantly correlated with lower knowledge and attitude scores . the relatively low baseline hba1c level in this population of patients with advanced diabetes \n we found that the mean score for knowledge was 59.90 11.23 of the maximum 86.36 score possible . \n the low level of knowledge of disease in type 2 diabetes mellitus patients on hemodialysis may reflect the low emphasis on patient education . \n in addition , the reason for a lower knowledge level in this study may be partly explained by the sample involving patients on dialysis , who are generally older and had lower education level ; patient 's age was between 50 and 88 years , mean ( sd ) 68.70 9.26 years , and most of them , 84 ( 71.7% ) , had primary educational degree . while coates and boore observed a higher mean knowledge score among their diabetic patients compared to our population , declaring that knowledge is only one of several variables that influence metabolic control . \n upadhyay and colleagues observed lower knowledge scores than the present study among their newly diagnosed patient population . \n we found that the majority of the diabetic patients in our survey had unfavorable attitude ( mean score of 44.27 8.35 with a maximum score of 62.50 ) . \n we suggest that this can be due to a low knowledge level among the patients as well as that of their healthcare team on how to improve their patients ' attitude . \n kozier and lea erb found that nurses had an important role for helping patients in changing their attitude and they can help in overcoming the barriers and support positive activities . in our study , patients ' mean practice score was low ( 45.06 12.87 with a maximum possible score of 72.73 ) . \n this can also be due to the subjects ' low education as well as their poor attitude towards their condition . \n kennedy et al . reported that education on self - care had positive influence on patients ' practice scores in their survey of mexican american women . in the study by niroomand \n et al . , patients ' knowledge , attitude , and practice ( kap ) were significantly higher than the present study which can be attributed to differences in study population , as they had evaluated diabetic patients without complications while we looked at diabetic patients receiving hemodialysis in the present study . \n while we observed a positive correlation between improved glycemic control as shown by lower fpg and hba1c levels and higher knowledge and attitude score , a study by mohammadi and colleagues showed no significant association was observed between kap score and glycemic control . \n their result was reflected by a similar study carried out among malaysian diabetes patients . while our observation seems more intuitive , as improved knowledge of disease and a better attitude should improve glycemic control , \n the differences in the results of these studies with our results may be explained by the differences in our specific population and the fact that they had all developed a serious complication . we have observed a significant association between patients ' knowledge and practice with their self - management behavior , which seems to be logical . \n however , toobert et al . showed that diabetic patients ' knowledge and practice were not related significantly to their self - management . \n again , this difference may be due to our specific population who consisted of elderly , poorly educated subjects with esrd . \n in contrast with the results from our survey , some studies have shown that there is no correlation between increased knowledge and metabolic control ( hba1c and bs ) ; beggan et al . \n noted that hba1c as an indicator of metabolic control was not correlated significantly with knowledge and germer et al . found no correlation between the level of knowledge and the level of control as measured by a random blood glucose or hba1c \n it is well established that patient contributions are very important for better management of diabetes . \n lack of knowledge of diabetes care among patients can have adverse effects on their capabilities to control diabetes . \n ckd has been indicated as one of the most common complications of diabetes by 72% of our subjects . \n awareness of measures to identify primary complications of diabetes , such as checking proteinuria and blood pressure monitoring , was poor , which reveals the need for effective diabetes education programs in developing countries like iran , as it has been stated that knowledge regarding diabetes among the general population as well as those with diabetes is still insufficient in iran and a good diabetes education program is greatly required . \n there are few appropriate diabetes education programs in most governmental hospitals and the existing programs are weak . \n this study also has some limitations ; it was limited to type 2 diabetic patients receiving hemodialysis at academic hospitals and does not include the private sector . \n also , all the scores of knowledge , attitude , practice , self - care , and quality of life were scored from 0 to 100 to be comparable with other literatures . as the attitude and quality of life had negative scores in the questionnaire , we know that attitude scores more than 60 and quality of life scores more than 80 are considered positive . \n this study has measured the level of knowledge , attitude , and practice as well as self - care and quality of life among a diabetic population receiving hemodialysis . we have observed a low level of knowledge and attitude that is correlated with subjects ' practice scores as well as their glycemic control . \n it can therefore be deducted that investing in proper patient education that increases knowledge and awareness improves attitude and practice and translates to self - care and better quality of life is an imperative undertaking through all the stages of diabetes .", "role": "user" }, { "content": "background . type 2 diabetes is an increasingly common condition with several preventable microvascular complications such as kidney damage . \n nephropathy is expensive to manage , especially as hospital dialysis treatment . \n improving patients ' knowledge , attitude , and practice ( kap ) toward their condition can achieve better control , delay complications , and improve their quality of life . \n this study evaluated the kap and self - care behaviors of diabetic patients on dialysis and variables that affect it . methods . \n this cross - sectional study was conducted at shahid beheshti academic hospitals of tehran , iran . \n face - to - face interviews were held to fill five validated questionnaires : three evaluating kap , one evaluating self - management , and one evaluating quality of life . result . \n 117 diabetic patients on hemodialysis ( 42 females ) with mean ( sd ) age of 68.70 9.26 years were enrolled in the survey . \n the scores for patient 's kap , self - care , and quality of life were 59.90 11.23 , 44.27 8.35 , 45.06 12.87 , 46.21 10.23 , and 26.85 13.23 , respectively . \n there was significant negative correlation between patients ' knowledge and attitude with their glycosylated hemoglobin level and their fasting blood sugar . \n there was significant correlation between patients ' knowledge and practice with their self - care activities . \n conclusion . \n the present study suggests that patients ' kap scores have a practical effect upon self - care behavior . \n this highlights the needs for effective diabetes education programs in developing countries like iran .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: liver hydatidosis , the parasitic disease produced by taenia echinococcus granulosus , leads to suffering caused by the complications it generates in both the organ and the whole organism . \n general morbidity from hydatid cysts remains high , despite preventative measures taken in many countries . \n this high morbidity , generating sometimes - important hepatobiliary sequelae , fully justifies the continued interest and attention of clinicians and surgeons worldwide . \n today , modern medical therapy with anthelmintics has been shown to have some advantages , in particular for the prophylaxis of relapses in patients in whom surgery is prohibited . in 1985 , \n the treatment for hepatic hydatid cyst by echo- or tomographic - guided puncture was evaluated as a modern optimized alternative to surgical therapy . \n this minimally invasive treatment was initially received with restraint , because of fears about secondary peritoneal seeding and the possibility of alcohol - induced cholangitis from instillation of cysts that have cystobiliary communication . however , after the first reports of percutaneous puncture of a hepatic hydatid cyst followed by alcohol instillation , there have been numerous articles showing that the method is safe and efficient and provides good results . \n the laparoscopic approach to the hydatid cyst emerged in 1993 as an alternative to the classic surgical treatment . \n for this retrospective study , we reviewed the data of all patients admitted with liver hydatidosis between 1995 and 2014 . \n there were 148 men ( 41% ) and 211 women ( 59% ) , with a mean age of 36.8 years ( range , 667 years ) . \n the most frequent clinical symptom was diffuse abdominal pain ( 179 cases , 49.8% ) . \n hepatomegaly was encountered in 98 patients ( 27.2% ) and abdominal discomfort in 74 ( 20.6% ) . \n other signs or symptoms were allergic reactions , jaundice , and acute pancreatitis ( table 1 ) . \n it is important to mention that more than 30% of patients were asymptomatic ; the diagnoses were established incidentally during a routine ultrasound examination . \n symptoms of patients with liver hydatidosis percentage based on a total of 359 patients . in our group , there were 14 patients ( 3.8% ) who had undergone surgical procedures for liver hydatidosis , and they presented with a recurrence of the disease after 210 years . \n all 359 patients underwent a preoperative ultrasound , and the cysts were initially classified according to gharbi 's system . \n after the introduction of the world health organization 's informal working group on echinococcosis ( who - iwge ) classification in 2003 , we used that ultrasound classification method ( table 2 ) . \n the number of cysts encountered was 557 : 86 patients had 2 cysts and 56 had 3 ( table 3 ) . \n who - iwge classification of liver hydatid cysts four hundred nine cysts were located in the right liver lobe , and the mean diameter of the cysts was 6.7 cm ( range , 319 cm ) . \n there were also multiple locations of the cysts : lung ( 7 cases ) , spleen ( 3 cases ) , pancreas ( 2 cases ) , peritoneum ( 2 cases ) , and diaphragm ( 1 case ) ( table 4 ) . \n all patients were treated with 1015 mg / kg albendazole , starting 1 to 3 days before the procedure and for 1 to 3 months afterward . \n we performed echo - guided puncture in the operating room in patients under general intravenous anesthesia . \n we started with the measurement of the cyst volume and then inserted an 1822-gauge echo - guided needle . \n it is very important to insert the needle through the liver parenchyma , to avoid spillage of the hydatid liquid . \n we aspirated as much liquid as was consistent with the hydatid cyst 's measured volume . \n we inspected to determine whether the suctioned liquid was clear , and alcohol , at a temperature of 98 degrees , was injected equal to one - third of the amount removed . \n initially , we selected the patients strictly from types cl and ce1 , but later we performed the procedure , even in patients with ce2 cysts . \n for the laparoscopic approach , we used the same manner as in the open approach in cases of partial pericystectomy . \n we put gauze dressing with hypertonic saline solution around the cyst and inserted the aspiration needle into the cavity , where we instilled hypertonic saline solution . \n after 10 min , we aspirated the cysts and drilled a small hole in them for better aspiration of the hydatid liquid . \n we extracted the germinative membrane or daughter vesicles and put them into an endobag ( covidien , dublin , ireland ) . \n we controlled the cavity of the cysts and , if biliary leakage appeared , we performed a suture of the biliary fistula . \n in a group of 359 patients , minimally invasive treatment was performed in 267 ( 74.3% ) and open surgery in 92 ( 25.7% ) ( table 4 ) . \n we employed the pair ( puncture , aspiration , injection , and respiration ) technique in 208 patients ( 57.9% ) , and opted for a laparoscopic approach in 59 ( 16.4% ) ( table 5 ) . \n only patients with cl , ce1 , and ce2 liver hydatid cysts were selected for minimally invasive treatment ( puncture or laparoscopy ) after who - iwge sonographic classification of the liver hydatidosis . for the laparoscopic approach , \n the cysts were located mostly in the left liver lobe or in the lateral segments , as they were easy to manage . after gaining sufficient expertise in the laparoscopic field \n , we performed the laparoscopic approach , even for types ce3 , ce4 , and ce5 . in terms of location \n , we can now resolve any segment of the liver laparoscopically , except for those cysts located in the central segments ( figure 1 ) . \n all patients were followed up for a mean of 61.7 months ( range , 16127 ) . \n postoperative follow - up consisted of clinical examination , laboratory investigation , abdominal ultrasound , and computed tomography . \n the patients treated by echo - guided puncture were cured in 95.2% of cases ( 198 patients ) . a decrease in the hepatic cavity \n we encountered a mean decrease in cavity of 73% after 1 month ( range , 54100% ) and 89% after 1 year ( range , 72100% ) ( figure 2 ) . \n six patients ( 2.8% ) from the echo - guided puncture group underwent a repeat of the procedure , because the cavity did not disappear after 2 years . \n four patients ( 2% ) needed a classic reoperation , in 2 cases because of the development of liver abscesses and in 2 others because of biliary fistulas . \n we had 8 patients ( 3.8% ) with allergic reactions after puncture that were easily controlled with corticoids and antihistamines . \n the patients treated by the laparoscopic approach were cured in 93.2% of cases ( 55 patients ) . in 4 cases \n , we had to perform an open procedure : in 2 patients for of a recurrence after 2 years , in 1 patient for a liver abscess , and in 1 for a biliary fistula ( figure 3 ) . \n the mean hospital stay was 2.9 days ( range , 15 ) after an echo - guided puncture and 3.6 days ( range , 28 ) after a laparoscopic procedure . \n initially , open surgery was the only accepted treatment for this disease . in recent decades , however , dramatic changes have taken place . \n the first was the introduction of percutaneous echo - guided puncture , which was met with strong opposition . \n in fact , the procedure contravenes many of the principles of hydatid surgery , such as inserting a needle into the cyst cavity without the fear of disseminating the hydatid liquid . for this reason , \n there are several recommendations associated with it , such as that the needle should always be inserted through the liver 's parenchyma to avoid spreading the liquid contents . \n there are no randomized studies to compare the results of percutaneous treatment with other surgical procedures . \n gupta et al published a retrospective study that compared 52 patients treated with the pair technique , with or without drainage , with 61 patients treated with radical / excisional surgery and 33 with conservative surgery . in 10 patients , \n the pair procedure was abandoned because of an initial aspiration of an unclear liquid , which indicates a cysto - biliary communication . \n it was concluded that for a safe pair procedure , it is very important to select only patients with type i or ii cysts , according to gharbi 's classification . in our study , \n the percentage can be explained by the changes in the early diagnosis of liver hydatidosis which translates into higher percentages of type cl , ce1 , and ce2 cysts , in which percutaneous treatment is the procedure of choice , with very good results . \n we noted that age is an important factor in the time needed for disappearance of liver cavities . \n thus , children need healing time that averages up to 1 year , but in patients over 50 years of age , a decrease in the maximum diameter of the cavity took up to 2 years . \n if the cavity had not disappeared after 2 years , we performed another puncture , as happened in 6 patients . \n there are no randomized studies to compare open versus laparoscopic treatment of liver hydatidosis . in a retrospective study , \n zaharie et al compared 59 patients treated with the laparoscopic approach with 172 patients treated with open surgery . \n they concluded that the laparoscopic approach is safe for the treatment of liver hydatidosis in almost all segments of the liver . in our study , after the first period , we selected only cysts located in the left lobe , but now we consider that cysts in almost all segments are suitable for the laparoscopic approach , and almost all types of cysts can be resolved using this approach . in our experience , \n , there are many methods described for avoiding leakage of the hydatid liquid at the moment of the first insertion of a needle into the cyst . in our opinion , isolating the area around the cyst , using precautions when inserting the needle , and administering albendazole for at least 1 month after the procedure is sufficient , and we did not have any peritoneal recurrences after using the laparoscopic or percutaneous approach . \n in dealing with the hepatic hydatid cyst , treatment must be adapted to each patient , depending on the stage of development , location , size , and complications of the cyst . \n classic radical or conservative surgery should remain an option for solving complicated cysts . for simple cysts \n , the uncomplicated minimally invasive treatment option should be considered the best course of action . \n both the laparoscopic approach and the ultrasound guided puncture are safe and effective procedures , but , with a difficult cyst location , a puncture should be considered .", "role": "user" }, { "content": "background and objectives : open surgery has been the mainstay treatment for liver hydatidosis in the past . today , for treatment of simple and uncomplicated cysts , we have a variety of choices : antihelmintic therapy , the pair ( puncture , aspiration , injection , and respiration ) technique , and the laparoscopic approach . \n we reviewed our series of 267 cases of hepatic hydatidosis submitted to surgery over a period of 20 years , from 1995 through 2014 , comparing the results of these minimally invasive treatments.methods:in 92 patients ( 25.7% of cases ) who presented with complicated liver hydatid cysts , we performed open surgery . in 16.4% of cases ( 59 patients ) , we used a laparoscopic approach , and in 208 patients ( 57.9% of cases ) , we used the pair technique . \n all patients were monitored after surgery for a mean of 61.7 months ( range , 16127 ) . \n postoperative follow - up consisted of clinical examination , laboratory investigation , abdominal ultrasound , and magnetic resonance imaging.results:almost all patients ( 198 , 95.2% ) treated with the pair technique and 55 patients ( 93.2% ) treated with the laparoscopic approach were cured . \n six patients ( 2.8% ) from the echo - guided puncture group had to undergo a repeat of the procedure because the cavity did not disappear after 2 years . in 4 patients ( 2% ) , we performed open surgery for 2 biliary fistulas and 2 hepatic abscesses . \n four patients from the laparoscopic group needed additional procedures . \n open surgery was necessary in 2 patients for a recurrence after 2 years ; 1 patient had developed a liver abscess and the other had a biliary fistula.conclusions:in conclusion , open surgery remains the viable option for complicated cysts , with biliary communication , with multiple daughter vesicles , or with calcified walls . for simple , uncomplicated hydatid cysts , both methods ( the pair technique and laparoscopic procedure ) are safe and efficient , with very good results and low morbidity rates .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: evidence - based medicine ( ebm ) has been defined as the integration of best research evidence with clinical expertise and patient values . \n the first historical descriptions of ebm date back to the beginning of 1990s , when the work of gordon guyatt , david sackett and others established the emerging methodologies of ebm , . \n the main products of ebm are evidence - based guidelines ( ebgs ) , systematically developed statements to assist practitioner and patient decision about appropriate health care for specific clinical circumstances . \n costs , ethical concerns in placebo - controlled trials , publication bias and a real risk of reductionism are the most emphasized limitations of ebm . in order to overcome these limitations and improve ebgs quality standards , different societies ( among which the world health organization , who ) produced guidelines for guidelines developers . \n preliminary steps for guideline development are evaluation of priority settings , composition of an expert panel , management of conflicts of interests , determination of appropriate group processes , of important outcomes and of which evidences have to be included . \n then developers have to produce synthesis and presentation of evidences , exposing criteria for grading evidence and recommendations , integrating when possible values ( e.g. ethical considerations ) and consumer involvement . \n next , considerations of cost - effectiveness , affordability and resource implications , of equity , applicability , transferability and adaptation should be included . \n the final steps are the report of guidelines recommendations , the dissemination and implementation of guidelines and their evaluation . \n the appraisal of guidelines for research and evaluation ( agree ) instrument was a validated , easy - to - use , and transparent tool , which was internationally developed and widely accepted . \n it was developed through a process of item generation , selection and scaling , field - testing and refinement . \n the final version of the instrument contained 23 items grouped into six domains : scope and purpose , stakeholder involvement , rigor of development , clarity and presentation , applicability , and editorial independence . despite the good review of the agree instruments , two important limitations are present : although it can be used to compare clinical practice guidelines , agree instrument does not set a threshold to classify them as good or bad , and it does not assess the quality of the evidence supporting the recommendations . \n level of evidences and grade of recommendations in fact do not necessarily correlate , since the first is a measure of scientific strength and the latter of clinical utility . \n recently , an improved version of the agree , i.e. the agree ii instrument , has been released , , partly overcoming the previous limitations . indeed , the introduction of the new item assessing the description of strengths and limitation of the body of evidences can be considered as a precursor for clinical validity or appropriateness of the recommendations . \n the authors recognize the value of this point , in fact they state that the agree consortium is targeting this area as its next priority for further study in the agree a3 initiative . in our opinion , correlating level with grade could be a valid way to integrate the agree ii instrument and quickly display the internal consistence of ebgs . \n the guidelines for the treatment of bone metastases by the italian society for medical oncology ( aiom ) are based on : european society for medical oncology ( esmo ) guidance on the use of bisphosphonates in solid tumors and on the management of aromatase inhibitor - associated bone loss ; cochrane network reviews ; critical review of the literature updated to june 2009 . \n the topics covered by the aiom guidelines are use of bisphosphonates in metastatic cancers ; use of bisphosphonates in the prevention and treatment of cancer treatment induced bone loss ; safety of bisphosphonates use ; treatment of bone metastases pain ; role of bisphosphonates in specific settings ; role of orthopedic surgery in bone metastases ; role of radiotherapy in bone metastases . \n level of evidences ( i vi ) and grade of recommendations ( a e ) were provided according to the recommendations of the italian centre for the evaluation of the efficacy of health assistance coordinated by the italian national health institute ( istituto superiore di sanit ) and are presented in table 1 . \n we performed an analysis of levels of evidence and respective grades of recommendations of the guidelines for treatment of bone metastases by aiom . \n spearman 's rank correlation coefficient was calculated per each topic of the guidelines , a p value < 0.05 was considered statistically significant . \n the final correlation was performed using a linear regression model ( graphpad prims version 5.04 , la jolla california usa ) ; linear r value was reported to weight the results and a p value < 0.05 was considered statistically significant . \n the results of our analysis showed a statistically significant correlation between the levels of evidence and the grades of recommendation in the following topics : use of bisphosphonates in metastatic cancers ( p<0.01 ) ; use of bisphosphonates in the prevention and treatment of cancer treatment induced bone loss ( p<0.01 ) ; safety of bisphosphonates use ( p<0.05 ) ; role of bisphosphonates in specific settings ( p<0.01 ) ; role of orthopedic surgery in bone metastases ( p<0.0001 ) ; role of radiotherapy in bone metastases ( p<0.01 ) . \n finally , a statistically significant correlation was also found considering all the levels of evidence and grades of recommendation together regardless of the division in topics ( r=0.4454 , p<0.0001 ; fig . \n ebgs represent a milestone for modern evidence - based clinical practice ; they indeed substantially improve clinical care . \n nevertheless , ebgs frequently vary widely in quality , , thus their evaluation is of critical importance . among several evaluation tools , \n the agree instrument is the most widely used , even though it has known limitations , i.e. the impossibility to classify ebgs as good or bad and to assess the quality of the evidences supporting the recommendations . in order to overcome these limitations \n , we performed an analysis of levels of evidence and respective grades of recommendations of the guidelines for treatment of bone metastases by aiom . in six out of seven topics , \n moreover , a statistically significant correlation was also found considering all the levels of evidence and grades of recommendation together regardless of the division in topics . \n these results indicate that the authors of the guidelines worked scientifically with a correct approach and that these guidelines are likely to be adherent with modern medical literature . \n however , we can not exclude that a significant correlation for some topics could be due to low levels of evidences from medical literature and consequent low grades of recommendations . \n moreover , the lack of concordance in specific items could also derive from the impossibility for the physicians to prescribe a specific drug in a specific setting ( i.e. low grade of recommendation ) due to the delayed approval by regulatory agencies ( e.g. fda , ema ) even in presence of adequate scientific literature ( i.e. high level of evidence ) . \n the critical evaluation of ebgs is an underestimated issue in current clinical practice . moreover , specific methodological aspects for the evaluation of ebgs are of increasing interest in the medical oncology community . \n here we provide clinicians with a quick tool to evaluate the internal consistence of ebgs . \n further analysis should confirm the reliability of this method , which could be easily implemented in future ebgs .", "role": "user" }, { "content": "modern clinical practice relies on evidence - based medicine ( ebm ) and evidence - based guidelines ( ebgs ) . \n the critical evaluation of ebgs value is therefore an essential step to further improve clinical practice . in our opinion , \n correlating levels of evidence and grades of recommendation can be an easy tool to quickly display internal consistence of ebgs .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: neurodegenerative diseases such as alzheimer s , huntington s , and parkinson s are globally prevalent disorders that result in region specific neuronal loss and consequent movement and behavioral disorders . \n dysfunction of learning and memory is one of the most prominent symptoms of alzheimer s and parkinson s diseases . \n this feeble group may be exposed to insults like drugs , infection and trauma that may cause neurodegeneration and hence impair the development of cns . \n brain derived neurotrophic factor ( bdnf ) is a growth factor that belongs to the nerve growth factor ( ngf ) family of peptides . \n this peptide has established effects on neuronal proliferation , regulation of neuronal function and synaptic plasticity . \n bdnf has shown important roles in learning and memory by enhancing the efficacy of synapses in the hippocampus . \n the bdnf gene in the rat contains eight 5 noncoding exons ( i - ixa ) , each with a separate promoter and one 3 coding exon ( ix ) that comprises the entire open reading frame for bdnf protein . \n the expression pattern of bdnf gene in rodents is complex in that splicing of each of the eight noncoding i - ixa exons with the coding exon ix creates 10 transcript variants that all are translated to one same mature protein . since the discovery of these noncoding exons , \n although roles like effects on transcription regulation and stability , translation efficiency , and differential regulation of bdnf expression in the somatic or dendritic compartments were attributed to the untranslated regions of the bdnf gene , but their exact character is yet vague . \n a few studies have also reported the differential expression of noncoding exons i to ixa in response to some therapeutic / toxic factors . \n resveratrol ( rsv ) is a phytoestrogen with antioxidant activity and neuroprotective features that can pass blood brain barrier and placenta . \n thus , neuroprotective effects of resveratrol have been shown to be linked to increased neuronal survival through induction of sirt1 activity and subsequent decreases in neuroinflammtion and apoptosis . \n therefore , synaptic repair by bdnf is a new approach in the treatment of neurodegenerative disorders . \n endogenous production of bdnf may be a useful and noninvasive way to induce neurogenesis and promote synaptic repair and neuronal function improvement . \n we have already shown that oral resveratrol induces the expression of the exon ix transcript of the bdnf gene in rat hippocampal tissue . \n to better characterize this effect of rsv , we sought to determine its differential effects on the expression of exons i , iii , and iv and the common exon ix of the bdnf gene in the hippocampi of adult rats . \n further , we attempted to define any difference between the effects of rsv on the hippocampal expression of bdnf protein in adult and neonatal rats . \n thirty six female sprague - dawley rats weighing 200 - 250 g were provided by the laboratory animal center of shiraz university of medical sciences . \n every manipulation of rats before decapitation was done in the laboratory animal center of shiraz university of medical sciences in february 2013 . \n rats were mated and after detection of vaginal plaque , i.e , the first day of pregnancy , were divided into 3 groups of 12 as follows , ( i ) the control group that were gavaged with ethanol 10% as the vehicle , ( ii ) rsv 60 mg / kg bw / day , and ( iii ) rsv 120 mg / kg bw / day groups that were treated orally with resveratrol ( 98% purity from biotivia , usa ) . \n rats had free access to water and food in a 12-h cycle of light and darkness . \n oral administrations were started on day 1 of pregnancy and continued until day 20 at 9 am daily . \n 24 h after the last gavage , all rats were sacrificed by co2 inhalation and hippocampal tissues were dissected from both mothers and embryos . \n hippocampi from 4 adult rats and hippocampi from embryos of 4 mothers , in each group were pooled together to make one specimen . in the case of adult rats , \n the right and the left hippocampi were collected separately and allocated to the analysis of mrna and/or protein , respectively . in the case of embryos , half ( 2 - 4 ) of the embryonic hippocampi of each mother \n were collected for mrna analyses and the same number of tissues were pooled for protein assay . \n all procedures were approved by the animal ethics committee of shiraz university of medical sciences . \n right - hippocampal specimens from adult rats and whole hippocampi from half of the embryos were collected in biozol reagent ( bioflux , japan ) immediately after dissection and kept in -80 c until rna extraction . \n rna extraction was done by the biozol kit based on manufacturer s protocol and the samples were analyzed by spectrophotometry to define their concentration and purity . \n after treatment with dnase i ( fermentas , eu ) to remove any dna contamination , cdna synthesis was carried out using 5 ug of rna and 1 ul of oligo dt with thermo scientific revertaid first strand cdna synthesis kit ( fermentas , eu ) . \n the interested cdnas were amplified under the following conditions : an initial denaturation at 95 c for 30s , followed by 40 cycles of 95 c for 5s , annealing and extinction at 60 c for 30s . \n hypoxanthine guanine phosphoribosyltransferase ( hprt ) , glyceraldehyde-3-phosphate dehydrogenase ( gapdh ) were used as housekeeping gene and data were normalized relative to the expression level of the hprt gene . \n the ratio of expression level of bdnf exons was calculated by ct method . the quality and correct size of the pcr products \n sequences of primers used for qrt - pcr amplification of transcripts of interest expression of mrnas containing transcripts of exons i , iii , iv and ix of the bdnf gene in the adult rat hippocampus . \n a ) qrt - pcr analysis of the expression of exons i , iii , iv and ix in animals treated by either ethanol 10% ( as a vehicle ) or rsv for twenty days from day 1 to day 20 of gestation . \n b ) electrophoresis of the qrt - pcr products of exons i , iii , iv and ix of the bdnf gene in representative cases . \n the presence of pcr products with predicted lengths of about 159 bp , 152 bp , 148 bp and 212 bp , respectively , for exons i , iii , iv and ix of the bdnf gene was confirmed . \n left - hippocampal specimens from adult rats and whole hippocampi from half of embryos were frozen in liquid nitrogen immediately after dissection and kept in -80 c until protein extraction . \n protein extraction was done using extraction buffer containing np40 lysate buffer and protease inhibitor cocktail ( sigma - aldrich ) as proposed by the manufacturer . \n briefly , each homogenized sample was sonicated 3 times for 5s , and then centrifuged for 10 min at 10,000 g at 4 c and the supernatant was collected . \n protein concentration was measured by bradford method and 40 ug of each sample was fractionated on 15% sodium dodecyl sulfate \n polyacrylamide gel electrophoresis ( sds - page ) and transferred to nitrocellulose membrane at 100 v for 90 min ( mini trans - blot cell bio - rad , usa ) . \n membranes were blocked in 5% skimmed milk in 0.2% tbst for 1 h at room temperature and then membranes were incubated with either a 1:250 titer of the polyclonal rabbit antiserum against bdnf ( sc-546 , santa cruz , usa ) or a 1:500 dilution of the anti -actin antibody ( ab1801 , abcam , usa ) in 1% skimmed milk - tbst at 4 c overnight . \n this procedure was followed by washing the membrane 3 times for 20 min by 0.2% tbst and treatment with the secondary antibody ; 1:7500 goat anti - rabbit igg : hrp antibody ( aviva system biology , usa ) for 60 min at room temperature . \n after 3 times of washing with 0.2% tbst for 20 min , the membrane was developed by homemade ecl ( 250 mm 3-aminophthalhydrazide ( luminol ) , 90 mm p - coumaric acid , 30% h2o2 and 100 mm tris , ph 8.6 , and 1318 agfa x - ray films ) . \n the level of pro - bdnf protein of each sample was normalized to its cognate -actin and fold change of bdnf in the treatment groups were calculated relative to the control group . \n results were expressed as meansem and nonparametric analysis of variance ( kruskal - wallis test / mann - whitney u test with bonferroni correction ) was performed to diagnose any differences between groups . whenever significant differences were detected between groups by kruskal - wallis , bonferroni multiple comparison test was used as post hoc . \n all analyses were done using spss ( pasw statistic 18 ) and p<0.05 was considered to indicate significance . \n thirty six female sprague - dawley rats weighing 200 - 250 g were provided by the laboratory animal center of shiraz university of medical sciences . \n every manipulation of rats before decapitation was done in the laboratory animal center of shiraz university of medical sciences in february 2013 . \n rats were mated and after detection of vaginal plaque , i.e , the first day of pregnancy , were divided into 3 groups of 12 as follows , ( i ) the control group that were gavaged with ethanol 10% as the vehicle , ( ii ) rsv 60 mg / kg bw / day , and ( iii ) rsv 120 mg / kg bw / day groups that were treated orally with resveratrol ( 98% purity from biotivia , usa ) . \n rats had free access to water and food in a 12-h cycle of light and darkness . \n oral administrations were started on day 1 of pregnancy and continued until day 20 at 9 am daily . \n 24 h after the last gavage , all rats were sacrificed by co2 inhalation and hippocampal tissues were dissected from both mothers and embryos . \n hippocampi from 4 adult rats and hippocampi from embryos of 4 mothers , in each group were pooled together to make one specimen . in the case of adult rats , \n the right and the left hippocampi were collected separately and allocated to the analysis of mrna and/or protein , respectively . in the case of embryos , half ( 2 - 4 ) of the embryonic hippocampi of each mother \n were collected for mrna analyses and the same number of tissues were pooled for protein assay . \n all procedures were approved by the animal ethics committee of shiraz university of medical sciences . \n right - hippocampal specimens from adult rats and whole hippocampi from half of the embryos were collected in biozol reagent ( bioflux , japan ) immediately after dissection and kept in -80 c until rna extraction . \n rna extraction was done by the biozol kit based on manufacturer s protocol and the samples were analyzed by spectrophotometry to define their concentration and purity . \n after treatment with dnase i ( fermentas , eu ) to remove any dna contamination , cdna synthesis was carried out using 5 ug of rna and 1 ul of oligo dt with thermo scientific revertaid first strand cdna synthesis kit ( fermentas , eu ) . all procedures were done based on the manufacturer s protocol . \n the interested cdnas were amplified under the following conditions : an initial denaturation at 95 c for 30s , followed by 40 cycles of 95 c for 5s , annealing and extinction at 60 c for 30s . \n hypoxanthine guanine phosphoribosyltransferase ( hprt ) , glyceraldehyde-3-phosphate dehydrogenase ( gapdh ) were used as housekeeping gene and data were normalized relative to the expression level of the hprt gene . \n the quality and correct size of the pcr products were checked by electrophoresis on 1.6% agarose gels ( figure 1b ) . \n sequences of primers used for qrt - pcr amplification of transcripts of interest expression of mrnas containing transcripts of exons i , iii , iv and ix of the bdnf gene in the adult rat hippocampus . \n a ) qrt - pcr analysis of the expression of exons i , iii , iv and ix in animals treated by either ethanol 10% ( as a vehicle ) or rsv for twenty days from day 1 to day 20 of gestation . \n b ) electrophoresis of the qrt - pcr products of exons i , iii , iv and ix of the bdnf gene in representative cases . \n the presence of pcr products with predicted lengths of about 159 bp , 152 bp , 148 bp and 212 bp , respectively , for exons i , iii , iv and ix of the bdnf gene was confirmed . \n left - hippocampal specimens from adult rats and whole hippocampi from half of embryos were frozen in liquid nitrogen immediately after dissection and kept in -80 c until protein extraction . \n protein extraction was done using extraction buffer containing np40 lysate buffer and protease inhibitor cocktail ( sigma - aldrich ) as proposed by the manufacturer . \n western blot analysis was performed as previously described . briefly , each homogenized sample was sonicated 3 times for 5s , and then centrifuged for 10 min at 10,000 g at 4 c and the supernatant was collected . \n protein concentration was measured by bradford method and 40 ug of each sample was fractionated on 15% sodium dodecyl sulfate \n polyacrylamide gel electrophoresis ( sds - page ) and transferred to nitrocellulose membrane at 100 v for 90 min ( mini trans - blot cell bio - rad , usa ) . \n membranes were blocked in 5% skimmed milk in 0.2% tbst for 1 h at room temperature and then membranes were incubated with either a 1:250 titer of the polyclonal rabbit antiserum against bdnf ( sc-546 , santa cruz , usa ) or a 1:500 dilution of the anti -actin antibody ( ab1801 , abcam , usa ) in 1% skimmed milk - tbst at 4 c overnight . \n this procedure was followed by washing the membrane 3 times for 20 min by 0.2% tbst and treatment with the secondary antibody ; 1:7500 goat anti - rabbit igg : hrp antibody ( aviva system biology , usa ) for 60 min at room temperature . after 3 times of washing with 0.2% tbst for 20 min , \n the membrane was developed by homemade ecl ( 250 mm 3-aminophthalhydrazide ( luminol ) , 90 mm p - coumaric acid , 30% h2o2 and 100 mm tris , ph 8.6 , and 1318 agfa x - ray films ) . \n the level of pro - bdnf protein of each sample was normalized to its cognate -actin and fold change of bdnf in the treatment groups were calculated relative to the control group . \n results were expressed as meansem and nonparametric analysis of variance ( kruskal - wallis test / mann - whitney u test with bonferroni correction ) was performed to diagnose any differences between groups . whenever significant differences were detected between groups by kruskal - wallis , bonferroni multiple comparison test was used as post hoc . \n all analyses were done using spss ( pasw statistic 18 ) and p<0.05 was considered to indicate significance . \n real - time rt - pcr was performed on the adult rat hippocampus samples to assess the expression levels of mrnas containing transcripts encoded by any of the exons i , iii , iv and ix of the bdnf gene . as shown in the figure 1 , rsv ( 120 mg / kg bw / day ) increased the levels of bdnf exons i , iii , iv and the common exon ix as compared to the control group . \n this increase was statistically significant with respect to exons iii ( p=0.03 ) , iv ( p=0.03 ) and ix ( p=0.04 ) , but not to the exon i ( p=0.06 ) ( kruskal - wallis test / mann - whitney u test with bonferroni correction ) . \n rsv at the dose of 60 mg / kg bw / day tended to increase the levels of transcripts of the exons tested in this study , but the effect failed to achieve significance ( kruskal - wallis test / mann - whitney u test with bonferroni correction , p0.05 ) under our experimental conditions . \n we tried to evaluate the effects of rsv on the expression levels of the above exons in the hippocampi of embryos in the rsv treated rats . \n however , we were not able to do so because mrna expression of all of the three housekeeping genes we used showed strong changes in the rsv ( 60 mg / kg bw / day ) treated group when compared with the control group . \n we did western blotting to analyze levels of pro - bdnf protein in the hippocampi of adult and embryonic rats in response to two different doses of rsv . \n as depicted in figure 2 , rsv ( 120 mg / kg bw / day ) increased the levels of pro - bdnf protein in the hippocampi from adult rats , an effect that was not statistically significant ( data not shown ) . \n levels of pro - bdnf protein in the hippocampal tissues of embryos from rats treated by two doses of 60 and 120 mg / kg bw / day of rsv also remained unchanged as compared to control specimens ( figure 2 ) . \n expression pattern of pro - bdnf protein in hippocampi from adult rats and their embryos . \n anti bdnf antibody used in immunoblotting assays against extracts from hippocampal tissues , recognized a protein band of g~32 kda for pro - bdnf as expected . \n real - time rt - pcr was performed on the adult rat hippocampus samples to assess the expression levels of mrnas containing transcripts encoded by any of the exons i , iii , iv and ix of the bdnf gene . as shown in the figure 1 , rsv ( 120 mg / kg bw / day ) increased the levels of bdnf exons i , iii , iv and the common exon ix as compared to the control group . \n this increase was statistically significant with respect to exons iii ( p=0.03 ) , iv ( p=0.03 ) and ix ( p=0.04 ) , but not to the exon i ( p=0.06 ) ( kruskal - wallis test / mann - whitney u test with bonferroni correction ) . \n rsv at the dose of 60 mg / kg bw / day tended to increase the levels of transcripts of the exons tested in this study , but the effect failed to achieve significance ( kruskal - wallis test / mann - whitney u test with bonferroni correction , p0.05 ) under our experimental conditions . \n we tried to evaluate the effects of rsv on the expression levels of the above exons in the hippocampi of embryos in the rsv treated rats . \n however , we were not able to do so because mrna expression of all of the three housekeeping genes we used showed strong changes in the rsv ( 60 mg / kg bw / day ) treated group when compared with the control group . \n we did western blotting to analyze levels of pro - bdnf protein in the hippocampi of adult and embryonic rats in response to two different doses of rsv . \n as depicted in figure 2 , rsv ( 120 mg / kg bw / day ) increased the levels of pro - bdnf protein in the hippocampi from adult rats , an effect that was not statistically significant ( data not shown ) . \n levels of pro - bdnf protein in the hippocampal tissues of embryos from rats treated by two doses of 60 and 120 mg / kg bw / day of rsv also remained unchanged as compared to control specimens ( figure 2 ) . \n expression pattern of pro - bdnf protein in hippocampi from adult rats and their embryos . \n anti bdnf antibody used in immunoblotting assays against extracts from hippocampal tissues , recognized a protein band of g~32 kda for pro - bdnf as expected . \n we have used transcript - specific primers of the bdnf gene to show that hippocampal levels of bdnf transcripts containing different 5exons are differentially affected by oral resveratrol . \n recently , increasing body of data is pointing to the idea that changes in the splicing pattern of bdnf exons may be a new molecular mechanism of diseases . \n these data include those concerning the association of specific bdnf exon expression with neurological disorders , and those on the pharmacological manipulations that affect the exon specific expression of bdnf in the rodent tissues . \n rsv has been earlier reported to induce the level of the mrna encoded by the exon ix of the bdnf gene in the hippocampus of naive adult male and depression model of rats . here \n , we have extended these studies to the effects of the phytoestrogen , resveratrol , on the expression pattern of bdnf transcripts containing exons i , iii , iv and ix in the hippocampi of female rats . \n notably , sex hormones like estrogens have shown to strongly affect the expression and activity of bdnf through both transcriptional and translational mechanisms . \n our data are not sufficient to clarify the extent to which rsv has acted through estrogen receptors to produce the effects observed in this study . \n it protects neurons through multiple mechanisms like free radical scavenging , anti - inflammatory effects and modulation of programmed cell death and longevity via apoptosis inhibiting factor and sirt1 , respectively . \n additionally , rsv can work as an estrogen receptor agonist to show its neuroprotective features . \n our findings show that rsv increases the expression levels of bdnf transcripts containing exons iii , iv , and ix in a dose dependent manner , but fails to affect the expression of bdnf transcript containing exon i. this effect of rsv may either be attributed to its phytoestrogenic structure , as has been mentioned earlier that estrogen upregulates bdnf gene expression and activity , or back to its effect on gene transcription via upregulation of tcf - egr-1 transcription factors . \n these exons have shown to be the most inducible bdnf transcripts in response to kcl - mediated membrane depolarization in embryonic cortical neuron cultures and to kainite treatment . while exons iii and ix showed to be most highly induced by rsv under our experimental conditions . \n differential expression of the bdnf exons has also been shown in other experimental systems . despite the inducing effects of resveratrol on levels of the mrnas encoded by the coding bdnf exon ix as well as the non - coding exons iii and iv of the bdnf gene , pro - bdnf protein showed a small ( not significant ) increase in this study . \n the inconsistency between levels of bdnf protein and its encoding mrna has also been observed in rats treated by estrogens . \n these animals showed an increase in their hippocampal levels of bdnf mrna that was accompanied by a significant decrease in the bdnf protein . \n further , perovic et al . observed accumulation of pro - bdnf in the hippocampus of aged rat with no increase in the mrna level of bdnf . \n while exon i is reported to change remarkably in response to some treatments , it failed to show any significant changes under treatments applied in this study . on the other hand \n , it has been reported that an exon i specific translation start site more efficiently contributes to the synthesis of bdnf protein than the common translation start site located downstream of the splicing site of exons iii , iv and ix . \n our results show a slight non - significant increasing effect of rsv on the expression of the bdnf transcript containing exon i. this data is reminiscent of the changes we observed in the level of pro - bdnf protein . however , it is noteworthy that genes of regulation as those of bdnf usually show poor mrna - protein expression correlation , a topic that are discussed elsewhere in the literature . \n our study is the first on the effects of a phytochemical on the expression pattern of bdnf exons in the rat tissues . \n results of the present work are in line with the published data on the increasing effects of rsv on the expression of hippocampal levels of the exon ix containing bdnf transcripts in the naive rats and/or in the rats exposed to chronic unpredictable mild stress . \n comparable results were also obtained when intraperitoneal rsv was tested in mice models of depression . when testing effects of rsv on the expression pattern of exons of the bdnf gene in the rat embryonic hippocampi , we were encountered with dramatic changes in the expression of housekeeping genes . although , we tried three different housekeeping genes reported to be the most stable ones , but all of them showed instability in our rsv administered groups . the reason is speculated to be that levels of many housekeeping genes change during progression through the cell cycle . hence , we are not able to present our data on the expression of exons of bdnf in the embryonic rat hippocampus . \n more housekeeping genes need to be tested to find the one that shows stability under the experimental conditions of this study . at the protein level \n , we found no significant changes in the expression of pro - bdnf protein between control and rsv treated embryos . \n there is no report in the literature on the effects of rsv on the embryonic expression of bdnf . \n however , rsv has shown to improve the brain expression of bdnf in the postnatal day 40 rats whose mothers have been subject to restraint stress during gestational period . \n promoters of the bdnf gene have also shown to be a subject of epigenetic modifications . therefore , possible effects of rsv on the histone code and dna methylation need further investigation . although , results of most of the studies are in line with the neuroprotective effects of rsv , but some adverse effects of the compound have also been presented recently . \n thus , park et al . reported the antiprolifrative effects of rsv on the neuronal progenitor cells as well as the inhibitory effects of the phytochemical on hippocampal neurogenesis . \n these findings that are in contrast with the established neuroprotective effects of rsv may back to the dose of treatments , as rsv in low doses did not produce any inhibitory effect in the same work . \n these data reflect the importance of fine - tuning of rsv doses when used as a therapeutic agent . \n this study can be extended further to evaluate the effects of rsv on the expression of other non - coding exons of the bdnf gene as well as to assess the levels of the bdnf protein in both adult and embryonic rats . \n taken together , our data imply that promoters related to bdnf exons iii , iv , and ix may serve as points of regulation for transcription of the bdnf gene in the rat hippocampus . \n in addition , our findings indicate that rsv mimics effects of estrogen on the upregulation of bdnf expression .", "role": "user" }, { "content": "background : the induction of brain - derived neurotrophic factor ( bdnf ) expression in the hippocampus has shown to play a role in the beneficial effects of resveratrol ( rsv ) on the learning and memory . the bdnf gene has a complicated structure with eight 5 noncoding exons ( i - ixa ) , each of which can splice to a common coding exon ( ix ) to form a functional transcript . \n estrogens increase levels of bdnf transcripts in the hippocampus of rats . \n the aim of this study was to evaluate the effects of the phytoestrogen , rsv , on the splicing pattern of bdnf transcripts and on the pro - bdnf protein in the hippocampi of mother rats and their embryos.methods:rsv ( 60 or 120 mg / kg bw / day ) was administered orally to pregnant rats from days 1 to 20 of gestation . \n hippocampi of adults and embryos were dissected 24 h after the last administration of rsv . \n extracts from hippocampi were subject to quantitative ( q ) rt - pcr and western blotting to assess splicing pattern of the bdnf transcripts and levels of pro - bdnf protein , respectively.results:rsv ( 120 mg / kg bw / day ) caused a statistically significant increase in the expression levels of bdnf exons iii , iv and ix , but not the exon i in the hippocampi of adult rats ( p0.05 ) . \n levels of pro - bdnf protein remained unchanged in the hippocampal tissues from both adult and embryonic rats treated by rsv ( 60 or 120 mg / kg bw / day).conclusion : our results showed that rsv differentially activates promoters of the bdnf gene in the hippocampus of pregnant rats , but fails to affect the pro - bdnf level neither in adult nor in the embryonic hippocampal tissues .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: a duodenoscope is a flexible , lighted tube used during endoscopic retrograde cholangiopancreatography ( ercp ) for diagnosis and treatment of a variety of conditions of the biliary tree and pancreas , including ductal obstructions , stones , and malignancy . in korea , \n the number of procedures involving duodenoscope use is increasing each year since ercp is one of the best ways of resolving various problems caused by cancer , gallstones , or other conditions in the pancreatic and biliary ducts . \n however , physicians have not paid much attention to duodenoscope - related infection so far . \n the purpose of this article is to review recent reports on duodenoscope - related infections and to discuss important issues on its etiology and prevention . \n a duodenoscope has a very complex structure that contains many small parts such as an elevator and elevator channel , which make reprocessing more challenging . \n the difficulty in cleaning duodenoscopes contributes to a higher risk of infection than that associated with conventional gastrointestinal endoscopes . \n however , the importance of duodenoscope - related infections has been somewhat underestimated so far , with few guidelines specifically dealing with reprocessing of duodenoscopes . \n a duodenoscope has a similar disinfection process as that of other gastrointestinal endoscopes ; the process comprises eight steps of pre - cleaning , leakage testing , cleaning , rinsing , disinfection , rinsing , drying , and storage . \n the emergence of multidrug - resistant organisms , including carbapenem - resistant enterobacteriaceae ( cre ) such as escherichia coli and klebsiella pneumoniae , is a serious concern at home and abroad . \n recent outbreaks of cre bacterial infections associated with duodenoscopes used for ercp procedures have raised many concerns worldwide . \n incidents of duodenoscope - associated cre infection have been reported in canada and the united states.1 investigations of these outbreaks identified the cause as poor reprocessing technique and failure to follow guidelines on cleaning and disinfection of endoscopes . \n however , more recently reported outbreaks are more disturbing because investigations revealed that the infections occurred despite strict adherence to recommended reprocessing procedures.23 these reports have attracted much attention of healthcare professionals worldwide regarding the adequacy of current guidelines on cleaning and disinfection of endoscopes . \n the united states food and drug administration ( fda ) finally issued a safety communication on duodenoscope cleaning on february 19 , 2015 , which stipulated that the complex design of ercp endoscopes ( also called duodenoscopes ) may impede effective reprocessing and that duodenoscope - related infection might still occur even when the manufacturer 's reprocessing instructions are followed.4 therefore , instructions for reprocessing of duodenoscopes are essential for reducing the risk of duodenoscope - related infections among medical facilities . in other words , \n the importance of duodenoscope reprocessing , especially pre - cleaning , can not be over - emphasized . \n establishing the method of reprocessing specific to duodenoscopes is essential since a duodenoscope has unique structures such as an elevator and elevator channel , which present a challenge for cleaning and disinfection . \n however , moving parts in the elevator mechanism contain crevices that might not be reached by cleaning brushes and thus body fluids and organic debris might remain in those crevices and might act as a reservoir for serious infections . \n the materials comprising duodenoscopes are heat labile and require thorough disinfection with chemical agents or low - temperature sterilization.5 the most widely used disinfectants today are glutaraldehyde , peracetic acid , hydrogen peroxide , and electrolyzed acid water . however , since recent outbreaks of cre infections occurred after thorough cleaning and disinfection , the efficacy of disinfection is questionable . \n recently , the centers for disease control and prevention in the united states reported that high - level disinfection of ercp endoscopes with ethylene oxide ( eto ) sterilization stopped the outbreak of cre infection.6 however , other studies indicate that disinfection with widely used disinfectants such as peracetic acid is fully effective against multidrug - resistant bacteria.789 as the studies show conflicting results , more studies are needed to evaluate the efficacy of eto sterilization and other disinfectants . \n thus far , there are no data to recommend eto sterilization for disinfection of duodenoscopes . in addition \n , the complex structure of a duodenoscope causes difficulty in cleaning and disinfection of the duodenoscope . \n therefore , redesigning its structure to facilitate reprocessing is a long and time - consuming but an important step toward preventing duodenoscope - associated infections . \n further studies on failure modes of duodenoscope - related infection will help to identify flaws in duodenoscope design and possibly aid in redesigning the instrument . \n duodenoscope - associated infections involving cre or other multidrug - resistant bacteria pose a great threat to patients undergoing procedures using duodenoscopes and should be dealt with great concern . \n updated guidelines regarding cleaning and disinfection of duodenoscope need to be developed urgently to prevent transmission of infection and ensure patient safety . \n meanwhile , healthcare staff should pay special attention to thorough cleaning and disinfection of duodenoscopes . \n healthcare professionals should strictly follow the cleaning instructions provided by the duodenoscope 's manufacturer , especially the instructions for brushing the area around , near , and behind the elevator located at the distal end of the duodenoscope . \n high - level disinfection , using an fda - cleared aldehyde - based disinfectant or an oxidizing agent , should be carried out with proper protocol .", "role": "user" }, { "content": "a duodenoscope has a very complex structure that contains many small parts which make reprocessing more challenging . \n the difficulty in cleaning duodenoscopes contributes to a higher risk of infection than that of conventional gastrointestinal endoscopes . \n however , a duodenoscope shares similar disinfection process with other gastrointestinal endoscopes . recent outbreaks of carbapenem - resistant enterobacteriaceae ( cre ) infections associated with duodenoscopes used for endoscopic retrograde cholangiopancreatography procedures have raised many concerns worldwide . \n duodenoscope - associated infections involving cre or other multidrug - resistant bacteria pose a great threat to patients undergoing procedures using duodenoscopes and should be dealt with a great concern . \n updated guidelines regarding cleaning and disinfection of duodenoscope needs to be developed urgently to prevent transmission of infection and ensure patient safety . \n meanwhile , healthcare staff should pay special attention to thorough cleaning and disinfection of duodenoscopes .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: the human gait should be efficient and economical , concurrently requiring a complex integration of both the nervous system and the musculoskeletal system . \n clinical analysis of gait involves the measurement of essential biodynamic parameters and the interpretation of this information in conjunction with the therapeutic prescription or indication . \n this is widely used in the evaluation of pathologic gaits , where movements are frequently complex and difficult to evaluate with the naked eye.1 one of the most important gait alterations occurs as a result of cerebrovascular accidents ( cva ) . \n craik and oatis2 assert that approximately 70% of patients who survive a cva recover their ability to deambulate . \n this alteration is due to deficiencies in perception - cognition , motor control , joint mobility , strength and muscle tone.3 there is still no consensus among different specialists on the subject of kinematic variation during the hemiparetic gait ; one of the most frequently discussed joints is the knee , including the main changes that take place during the gait cycle49 and whether the gait velocity changes the patterns of joint mobility.10 this study aims to evaluate the variables found in the angular kinematics of knee joint and to describe the alterations found in the hemiparetic gait resulting from a cerebrovascular accident . \n mean weight was 67.6 16 kg ( range 44110 ) and mean height was 161.3 9.7 cm ( range 136189 ) . \n the inclusive criteria utilized included : diagnosis of a disability resulting from an ischemic cerebrovascular accident with right or left hemiparesia ; having the lesion for not less than 12 months ; being a community deambulator ; not presenting the need for auxiliary means of accomplishing their gait ; being able to walk barefoot ; and having not previously been through orthopedic surgical procedures . \n all subjects in the study had clinical indications for 3-d evaluation and were sent to the laboratory for medical prescriptions . \n as soon as the subjects met the inclusion criteria above , their consent to use the final report of their exams in this study was requested , as well as a signature of a signature on their declaration of consent . \n the sample was collected at the gait laboratory of the association for the assistance of the disabled child [ aacd ] in the city of so paulo . \n after both the anamnesis and evaluation ( inclusion criteria ) , the individuals were submitted to the protocol of anthropometric measurements for the execution of the 3-d gait exam , which was composed of height , weight , distance between both anterior and superior iliac spines , length of the lower limbs , diameter of knees and ankles , and measurement of the tibial torsion . \n the individuals were acquainted with the equipment and the procedure , and were instructed about the activities to be carried out . \n fifteen anatomic areas were selected and adopted as a reference for the fixation of the motion markers to the vicon 370 movement analysis system . \n helen hayes motion markers were used to estimate the position of the joint centers11 and to calculate the 3-d kinematics of the pelvis , hip , knee and ankle joints.12 the task was to walk on a track ( which was 90 cm by 6 m and marked on the floor ) 12 times or to perform 12 complete gait cycles . \n the individuals were instructed to deambulate at a comfortable velocity similar to their daily gait . for every circuit made on the experimental track \n , one single gait cycle was chosen using the mean values . using the vicon clinical manager program , \n the 3-d kinematics data of the pelvis , hip , knee and ankle joints were expressed graphically with the angular position of the joint versus time , resulting in twelve graphics per individual . from the total of twelve cycles , \n this selection was based on the internal evaluation protocol of the aacd gait laboratory , which has , as a parameter , the average value for the angular kinematics and the average gait velocity . this same cycle was used for data analysis of the knee angular kinematics on the sagittal plane . based on the graph for the knee joint on the sagittal plane , \n 11 variables were defined : knee angular position in the initial contact ( degrees ) ; knee first flexion peak in the stance phase ( degrees ) ; time of knee flexion peak in the stance ( % of stance ) ; minimum value of the angular position after the flexion peak in the stance ( degrees ) ; time of minimum value in the stance ( % of stance ) ; angular position in the terminal stance ( degrees ) ; angular velocity in the terminal stance ( degrees / % of the cycle ) ; flexion peak in the swing ( degrees ) ; angular velocity in the swing ( degrees / % of the cycle ) ; time of flexion peak in the swing ( % of the swing ) ; and movement amplitude in the swing ( degrees ) . \n the comparison groups were formed based on the gait velocity parameter , considering the median ( non - parametric distribution ) of all velocities gauged . \n two large groups were formed : a group with lower or equal velocity in relation to the median , and a group with higher velocity in relation to the median . \n each of these groups was divided into two subgroups , according to the side affected by the hemiparesis , which was either right or left . \n four groups were formed : group 1 - lower velocity and left hemiparesis ( lvlh ) , comprised of 23 individuals ; group 2 - lower velocity and right hemiparesis ( lvrh ) , comprised of 10 individuals ; group 3 - higher velocity and left hemiparesis ( lvlh ) , comprised of 7 individuals ; and group 4 - higher velocity and right hemiparesis ( lvrh ) , comprised of 26 individuals . \n possible changes among the groups , according to previously defined variables , were analyzed by the non - parametric test for kruskal - wallis independent samples . \n the means were calculated , but the standard deviation was not calculated because variables found using the non - parametric test do not have a standard distribution . \n the rejection level for the null hypothesis was fixed to be less than or equal to 0.05 ( 5% ) . \n the angular kinematics results for each individual are presented in figure 1 and are divided into the four groups according to the evaluation parameters , i.e. , the relation to gait velocity median and the side of hemiparesis . across the groups , \n no significant statistical differences was detected for several variables : knee angular position in the initial contact , knee flexion peak in the stance phase , minimum value of the angular position after the flexion peak in the stance , time of minimum value in the stance , angular position in the terminal stance , and angular velocity in the terminal stance ( table 1 ) . \n the other variables did show significant statistical differences : time of knee flexion peak in the stance ( p 0.05 ) , knee flexion peak in the swing ( p < 0.001 ) , angular velocity in the swing ( p = 0.01 ) , time of flexion peak in the swing ( p = 0.01 ) , and the value of the movement amplitude in the swing ( p 0.05 ) ( table 2 ) . \n the first characteristic found in the assessed groups shows that all groups place the knee in the initial contact in accordance with the literary description.13,14 burdett et al.4 have described an increase in knee flexion during initial contact at normal velocity . \n olney,15 however , asserts that the velocity variation interferes with knee flexion , leading to an increase in flexion when the velocity is higher . in papers by and richards,5 knutsson , 6 lehmann et al.,7 cozean et al.,8 and intiso \n et al,9 the values found in this study for knee position in the initial contact are different from the previous studies , occurring from a decrease in knee flexion in the initial contact . \n the values presented for the first knee flexion peak in the stance phase , which relates to the loading response event , are in agreement with the findings of burdett et al.,4 olney,15 and kerrigan.16 these authors also demonstrated smaller values for the knee position at this phase of the gait cycle in patients who had hemiplegia , as compared to those individuals with no neurological lesion , which is in agreement with our findings . \n nevertheless , perry13 disagrees with this because he asserts that there is a difference in the knee angular position in the loading response when the gait velocity is increased or decreased . \n the loading response contributes to smoothing rough changes in the trajectory arcs of the center of gravity ; in other words , this smoothes the arc through which the body s center of gravity moves . \n the change in this mechanism reduces both the quality and the quantity of shock absorption against the floor.17 the changes of this gait phase may have several causes : quadriceps muscle weakness with increasing knee flexion ; spasticity of the quadriceps muscle , which leads to a torn quadriceps at the initial moment of flexion ; hypertonia , which leads to premature knee extension ; and excess plantar flexion ( plantar flexion contracture and soleus muscle spasticity ) , which prevents the initial contact with the heel and causes the tibial bearing over the foot to be inhibited or blocked.4,1719 the time of the knee flexion peak in the stance was assessed ; it presented a statistically significant difference across the four groups studied . \n although the groups presented statistical differences in flexion time , their mean values varied from only 4.7% to 10.3% in the gait cycle . \n such values are inferior to the standard average gait values found in the literature , where the gait flexion peak takes place more than 15% of the way through the gait cycle.13,20 the minimum value for the angular position after the flexion peak in the stance , and the time of minimum value in the stance , were not statistically different across the groups . \n these variables show a trend that an increasing knee extension occurs , lasting longer during the stance in every group . \n the values found by kerrigan16 demonstrate results that vary from exceeding extension in stance to exceeding flexion at the same moment . \n mulroy18 asserts that in the first six months after a lesion , in patients who deambulate at a very slow velocity and in those who deambulate at a higher velocity , there is generally excess extension in the stance . \n however , beyond six months after a lesion , the problems found at this cycle moment were no longer relevant within this population . \n the literature presents findings similar to those of this study , along with possible reasons and counterbalances . \n kerringan21 believes that the excess extension may be related to weakness of the quadriceps , spasticity of the ankle plantar flexor , or contracture of the plantar flexor . as a result , the primary problems for these patients are the potential risks for articular capsule and ligament structure lesions in the posterior knee area , which may lead to pain , feeble ligaments and osseous deformity . \n dietz22 believes the cause of hyperextension may be spasticity of the plantar flexor , and this may alter the mechanical properties of the muscle and increase its resistance . an increase in ankle plantar flexion at the initial contact , without concomitant changes in muscle forces , \n intrinsic force - length - velocity properties of the muscle ( particularly the gastrocnemius and vastus ) diminished the effect of equinus posture alone , causing the abnormal knee extension to be less pronounced.23 for perry,24 the assertion is that part of the desired hip flexion is injured because of the increase in knee extension . \n furthermore , the stride length is decreased by the quantity of hip flexion that was lost . \n malezic25 and morris26 assert that the knee hyperextension pattern in the terminal stance hinders the average standard and knee extension during the initial stance , although subjects frequently perform the initial contact with the knee flexed and quickly evolve to complete extension or hyperextension . \n this also corroborates our findings about the knee angular position in the initial contact , the knee first flexion peak in the stance phase , and the time of knee flexion peak in the stance . \n although the knee hyperextension is a counterbalance , it presents several undesirable biomechanical effects , especially when it continues up to the terminal stance . \n knee hyperextension usually obstructs an effective impulse.27 in this case , the difficulty in flexing the knee causes the subject to perform the swing phase with the member extended , performing a circumduction7 or an ipsilateral hip elevation.28 none of these maneuvers provide suitable energy generation for the plantar flexor or hip flexor . \n this mechanism leads to a large loss , as this generation produces around 40% of the total gait consumption.15 the variable angular position in the terminal stance showed no statistically significant differences across the groups lvlh , lvrh , hvlh and hvrh . \n these values were higher than the standard values for normal gait29 and were not the same as those found by burdett et al.4 and olney,15 who described a reduction of the knee flexion in the terminal stance . \n our findings were similar that described by mulroy18 as one of the items that characterize the pattern of the hemiplegic gait . \n the group that had a very low - velocity deambulation presented hyperextension in the terminal stance , and in the group with middle velocity , hyperextension was also noted . in the group with near - normal velocity , the values were also close to the normal pattern , while the groups with limited velocity deambulation presented excess flexion . \n the findings of that study corroborate the values presented here . even when compared to control subjects walking at slow speeds , ankle plantar flexor work during pre - swing was greatly reduced in the hemiparetic subjects . \n differences in hip and knee moment work partially offset the reduction in ankle work , but net joint moment work was still significantly reduced.30 the angular velocity in the terminal stance had no statistically significant difference across the four groups selected for relation to the median velocity and the side of hemiparesis . \n notably , the angular velocity in the terminal velocity proved to be within the parameters of normal gait.13,29 the knee flexion peak in the swing revealed a statistically significant difference across the four groups . \n all groups presented mean values that were inferior to what was expected ; groups 1 and 2 , with left and right hemiparesis and lower velocity than the median , presented significantly lower values than what was described for the normal gait . \n groups 3 and 4 also show inferior values , although they are closer to what was expected for normal gait . for reduced flexion peaks , where the fastest group obtained higher values than the ones obtained by the group with the lower velocity , olney15 described results that were very close to the ones described above . \n inferior values to the ones described by the normality pattern were also published by knutsson and richards,5 knutsson,6 lehmann et al.,7 cozean et al,8 intiso et al,9 kerrigan et al,28 and mulroy et al.18 this gait pattern has historically been known as a stiff - legged gait and has been attributed only to quadriceps spasticity.3133 other causes , apart from abnormal quadriceps function , may include a dynamic weakness of the hip flexor3335 and a lack of control of the ankle during gait.33,36 kerrigan33 established relationships between the knee flexion reduction and the inappropriate activity of the hamstrings , and also between the knee flexion reduction and the lateness in removing the foot from the stance . \n kerrigan34 also showed that by simulating an increase in the hip flexion in a substantial model , there is an increase in knee flexion in some cases . \n riley and kerringan35 have confirmed the importance of the hip flexion using a more sophisticated approximation model . \n they have also described a complex contribution of the rectus femuris and hamstrings to a model that increases knee flexion and limits hip flexion . \n riley and kerrigan36 have demonstrated that torque over the hip , ankle and knee joints affects the knee in this event , using a somewhat new analysis technique to produce the acceleration described by kepple.37 in addition , kerrigan38 noticed a mean of 17 ( seventeen degrees ) of knee flexion peak reduction when healthy individuals walked on their toes compared to when they walked normally . \n such observation suggests that ankle function is sometimes related to knee flexion in the swing . \n the authors knutsson4 and olney15 revealed the presence of several gait patterns for people with hemiparesis . within this large number of patterns \n , there is a uniformity of some patterns , such as for knee flexion reduction in the swing.39 gait analysis was also performed in subjects who had a stroke ; imposed hip extension evoked a brief reflexive response in the quadriceps , followed by a heightened level of sustained activity . \n the initial response was velocity - dependent and was larger in the stroke group than in the control group . \n in contrast , the prolonged response was not velocity - dependent , was significantly greater in the rectus femuris and vastus lateralis in subjects with stroke , and , importantly , was correlated to decreased swing - phase knee flexion . \n hyperexcitable heteronymous connections from hip flexors to knee extensors appear to elicit prolonged quadriceps activity and may contribute to altered swing - phase knee kinematics following stroke.40 the knee flexion peak in the swing , the angular velocity in the swing , the time of knee flexion peak in the stance and the movement amplitude in the swing have presented statistically significant differences across all of the assessed groups . by observing the mean values demonstrated in table 1 , it is observed that groups 1 and 2 presented lower values for the flexion peak , higher angular velocity , shorter time to the flexion peak and inferior movement amplitude when compared to groups 3 and 4 . \n this relationship between the mean values can be understood by considering that the assessed subjects presented lesion - superior motoneuron and consequent elastic hypertonia , resulting in a velocity - dependent tone . \n the faster the muscle is torn , the higher the possibility of the spindle being torn and enabling a blocking or limitation of the movement . as a result , the knee tends to stop flexing and begin extending , making the time of the flexion peak occur earlier , limiting the flexion peak , and reducing the movement amplitude . \n the limitations found in this study and in other studies carried out with neurological patients involve the sample uniformity , despite our attempt to select patients who had both the same disease and the same topographic consequence \n . we can not be certain the neurological disease is the same . even with a more accurate diagnosis through the aid of imaging , we could not have better defined our population since we know that neural plasticity has several variables and influences . therefore , we have attempted to select patients with a diagnosis of advanced lesion and with similar consequences , i.e. , hemiparesis with upper limb prevailing , and to assess the biomechanical characteristics of these patients . dividing assessed groups according to velocity has been discussed by other authors.27,41 the division in relation to the hemicorpus taken was not aimed at assessing hemispherical lesion influences , as we did not consider the dominance and extension of the brain lesion when including the subjects . \n the knee joint was chosen because of its important biomechanical function during gait . in the swing phase , it is fixed and functionally reduces the lower limb , enabling the lower limbs to advance freely without touching the ground . \n in the swing , it flexes smoothly , enabling impact absorption , saving energy and transmitting strength to the lower limbs . \n undoubtedly , the changes found here may illustrate secondary , not primary , changes ; therefore , further assessment of this joint associated with the ankle , hip , pelvis and spine joints , in addition to the kinetics and electromyography evaluation , must be carried out so we can detect whether our findings are the cause or the consequence of the problem . \n to sum up , there were several relevant clinical characteristics found here that should be taken into account when choosing the best treatment . \n the important mechanisms include a loading response in the stance , knee hyperextension in the single stance , reduction of the flexion peak and movement amplitude of the knee in the swing phase , as previously discussed . \n we believe that our findings may aid in preventing the occurrence of the problems found , and also in finding the origin of these problems .", "role": "user" }, { "content": "introductionthere is still no consensus among different specialists on the subject of kinematic variation during the hemiparetic gait , including the main changes that take place during the gait cycle and whether the gait velocity changes the patterns of joint mobility . \n one of the most frequently discussed joints is the knee.objectivesthis study aims to evaluate the variables found in the angular kinematics of knee joint , and to describe the alterations found in the hemiparetic gait resulting from cerebrovascular injury.methodsthis study included 66 adult patients of both genders with a diagnosis of either right or left hemiparesis resulting from ischemic cerebrovascular injury . \n all the participants underwent three - dimensional gait evaluation , an the angular kinematics of the joint knee were selected for analysis.resultsthe results were distributed into four groups formed based on the median of the gait speed and the side of hemiparesis.conclusionsthe relevant clinical characteristics included the important mechanisms of loading response in the stance , knee hyperextension in single stance , and reduction of the peak flexion and movement amplitude of the knee in the swing phase . \n these mechanisms should be taken into account when choosing the best treatment.we believe that the findings presented here may aid in preventing the occurrence of the problems found , and also in identifying the origin of these problems .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: duchenne muscular dystrophy ( dmd ) and its less severe allelic form becker muscular dystrophy ( bmd ) are x - linked recessive devastating neuromuscular disorder that affects 1 in 3,500 males births and is caused by mutations in the dystrophin gene . \n the frequency and distribution of deletion in dystrophin gene in dmd population from northeast india is reported in the present work . \n a total of 69 patients were enrolled in this prospective study with clinically suspected dmd , attending the neurology clinic at gauhati medical college hospital , guwahati , assam between october 2009 and september 2011 . \n the diagnosis of dmd was based on the clinical findings of progressive and characteristic pattern of proximal muscle weakness , calf pseudohypertrophy , positive gower 's sign , valley sign , electromyography ( emg ) , an elevated serum creatine kinase ( ck ) activity , and the transmission of the pattern as an x - linked trait . \n screening of deletions of the dystrophin gene were performed according to chamberlain et al . and beggs et al . \n , using two multiplex pcr assays allowing the amplification of total 17 exons : the chamberlain reaction using primers for exons 4 , 8 , 12 , 17 , 19 , 44 , 45 , 48 , 51 and the beggs reaction performed with primers for the promoter and exons 1 , 3 , 6 , 13 , 43 , 47 , 50 , and 52 . \n the pcr products were separated on 2% nusieve + 1% agarose minigels and the bands were visualized by staining with ethidium bromide . \n baseline patient characteristics were reported using the median or mean sd for continuous variables according to their distribution . \n the families were divided in two groups according to the propositus multipex pcr analysis ( 13 deleted families and 6 non - deleted ) . \n wallis test for non - gaussian distributed continuous variables and chi - square analysis for categorical variables . \n screening of deletions of the dystrophin gene were performed according to chamberlain et al . and beggs et al . \n , using two multiplex pcr assays allowing the amplification of total 17 exons : the chamberlain reaction using primers for exons 4 , 8 , 12 , 17 , 19 , 44 , 45 , 48 , 51 and the beggs reaction performed with primers for the promoter and exons 1 , 3 , 6 , 13 , 43 , 47 , 50 , and 52 . \n the pcr products were separated on 2% nusieve + 1% agarose minigels and the bands were visualized by staining with ethidium bromide . \n baseline patient characteristics were reported using the median or mean sd for continuous variables according to their distribution . \n the families were divided in two groups according to the propositus multipex pcr analysis ( 13 deleted families and 6 non - deleted ) . \n wallis test for non - gaussian distributed continuous variables and chi - square analysis for categorical variables . \n out of 69 patients of dmd , 40 ( 58% ) were from the hindu community and 29 ( 42% ) from the muslim community , with age ranging from 2 - 9 years . \n the mean age of onset was 1.72 + 0.69 years ( range 0.8 - 3 years ) and the mean age at presentation was 6.24 + 176 ( range 2 - 9 years ) . \n all boys presented with progressive proximal muscle weakness particularly of the lower limbs and the majority ( 75.3% ) complained of calf muscle pseudohypertrophy . \n a total of 49 ( 71% ) cases showed intragenic deletions , the localization of these deletions are shown in figure 1 . \n majority of the deletions ( 42/49 , 85.7% ) were located at distal hot spot region that encompasses exons 44 - 55 and 14.3% of the deletions were located at the proximal hot spot region ( exons 2 - 19 ) . representing the gene , the localization , and the frequencies of deletions in 49 patients a total of 130 exons ( 108 in isolated cases , 22 in familial cases ) were deleted in 49 patients , and the average number of exons deleted per patients was 2.9 . \n single exon was deleted in 19 patients ( 38.7% ) , and in 30 patients ( 61.3% ) multiple exonic deletions were seen . \n most frequent single exon deleted were 45 and 47 , the most common exons involved in multiple deletions were 48 ( 36.7% ) , 47 ( 40.8% ) , and 50 ( 42.8% ) . \n the most frequent exon deletion in overall deletions were 50 ( 14.38% ) , followed by 48 ( 13.6% ) , 49 ( 12% ) , and 47 ( 10% ) . \n largest deletions were present in 6 patients extending from exon 44 to 52 in 5 patients and from exon 8 to 43 in 1 patient . on comparison between the familial and isolated cases of dmd , \n deletions were found in 72% of isolated cases and 68.4% in familial cases . out of 19 cases with family history , \n single exon deletion was seen in 7 and multiple exon deletion ( upto 3 ) in 6 cases . \n a previous study reported approximately 3% higher detection rate in familial cases as compared to sporadic cases . \n contrary to this , our study have shown approximately 4% reduction in deletion rate in familial cases ( p = 0.0084 ) . \n it is difficult to draw a definite conclusion as our series had a small sample size . \n multiplex pcr methods allow detection of approximately 98% of deletions , which accounts for 65% of all mutations . \n locations of deletions in the dystrophin gene are apparently nonrandom with a preponderance found in two hot spot \n regions at the 5 terminus and in the distal half of the central rod domain around exons 44 - 53 . \n the proportion of deletions in different populations of india shows a wide variation in the distribution . \n the reported frequency of deletion in various parts of india range from 62.1% to 74% using multiplex pcr , with which our data conforms . \n no particular reasons have been persuasively attributed to explain population - based differences in mutations of the dystrophin gene , it is presumed to be due to accumulation of differences in intronic sequences and their distribution over a time period as a consequence of genetic drift . \n such sequences unique to the population may favour intragenic deletions due to mismatch at the locus . in our study , \n 71% of patients showed deletions . in these patients , detection of dmd was done by deletion analysis using multplex pcr , hence eliminating the need to do muscle biopsy for diagnosis . \n as this disease has no effective therapy , early diagnosis of patient can be helpful for carrier detection and genetic counseling . with genetic counseling ,", "role": "user" }, { "content": "duchenne muscular dystrophy ( dmd ) is an x - linked recessive disorder that affects 1 in 3,500 males and is caused by mutations in the dystrophin gene . in this paper , we have reported dna analysis of dmd patients by multiplex polymerase chain reaction ( pcr ) from various states of northeast india . of the 69 clinically suspected patients of dmd , deletion was detected by multiplex pcr in 49 ( 71% ) patients . \n majority of the deletions ( 42/49 , 85.7% ) were located at distal hot spot region that encompasses exons 44 - 55 and 14.3% of the deletions were located at the proximal hot spot region ( exons 2 - 19 ) . in this study population , \n the deletion rate was 71% and was more frequent in the distal end exon .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: aflatoxins are highly toxic , mutagenic , carcinogenic , and teratogenic compounds contaminating a wide range of food commodities [ 1 , 2 ] . the major naturally occurring aflatoxins , namely , afb1 , afb2 , afg1 , and afg2 , constitute a class of structurally related toxic fungal metabolites . \n they are extremely potent carcinogens and can have significant economic impacts , making them important targets for detection and quantification . \n commodities frequently contaminated by aflatoxins include cereals , nuts , dried fruits , spices , and pulses [ 4 , 5 ] . \n when animals consume afb1 contaminated foodstuffs , the toxin is metabolized in the liver and excreted as afm1 via milk and urination . \n humans are exposed to the deleterious effects of aflatoxins either directly by eating contaminated grains or indirectly via animal products . \n evidence of hazardous human exposure to aflatoxins through various foods including dairy products has been shown by several investigators [ 13 , 7 ] . \n many analytical methods have been developed for estimation of aflatoxins in agricultural commodities . among them \n the optical detection method is regarded as one of the sensitive techniques for aflatoxin analysis . \n the optical signal is not influenced by electrical , magnetic , or ionic fields . \n table 1 gives an account of some of the reported biosensors for analysis of afm1 and afb1 . \n it is evident that the need for a highly selective multianalyte detection system is acute . \n simultaneous analysis of aflatoxins is essential to minimize the consumption of contaminated food and feed and import surveillance programs and controlling quality of products [ 5 , 8 , 9 ] . \n there is a need for development of single platform for simultaneous analysis of these toxins . \n few attempts have been made towards development of immunosensors capable of both discriminative detection and class - selective multianalyte analysis . \n in one such approach , multianalysis of aflatoxins was investigated by development of an immunoaffinity column . \n this was done by covalently coupling monoclonal antibody 1c11 against aflatoxins to amino - silica gel microparticles and then packing these into a cartridge . \n this immunoaffinity column was subsequently used for selective extraction of aflatoxins in agri - products . in a recent article , novel peptide mimics of aflatoxin ( mimotopes ) \n 5 such mimotopes were obtained and used in an indirect competitive elisa for analyzing total aflatoxin concentration in peanut and feedstuffs . in another interesting article , multianalysis of different triazine herbicides using cr of antibodies coupled to pattern recognition has been reported . \n a similar approach could be implemented for multianalysis of different aflatoxins which are structurally similar ( figure 1 ) . in this work , \n we performed fluorimetric analysis of afm1 using fitc conjugated secondary ( 2 ) antibody in 384 microwell plate as shown in figure 2 . \n the microwell plate was coated with anti - afm1 primary ( 1 ) monoclonal antibody ( mab ) which reacted with afm1 and partly recognized structurally similar aflatoxins such as afm2 , afb1 , and afg1 . \n subsequently we analyzed 2 real milk samples using standard addition method , and recovery rate was studied . \n afm1 , bovine serum albumin ( bsa ) , tween 20 , and certified reference material ( crm ) erm - bd282 ( afm1 in whole milk powder , < 0.02 g / kg ) were obtained from sigma - aldrich ( usa ) . \n acetonitrile ( acn ) hplc grade and sodium chloride ( nacl ) were purchased from merck ( germany ) . \n rat monoclonal [ 1c6 ] primary antibody ( 1ab ) of afm1 and fitc conjugated 2ab were purchased from abcam ( uk ) . \n milk samples were centrifuged by minispin plus centrifuge purchased from eppendorf ( germany ) and shaking of the samples were done by spinix shaker , purchased from tarsons ( india ) . \n 0.22 micron filter papers ( 25 mm diameter ) obtained from millipore ( usa ) were used for filtration of milk samples . \n white 384 well polystyrene microtiter plates were purchased from nunc ( denmark ) . for fluorimetric measurement , victorx 2030 optiplate reader from perkin elmer ( usa ) was used . \n a glove box , cole parmer ( usa ) , was used for the handling of all aflatoxin standard solutions . \n water produced in a milli - q system ( millipore , bedford , ma , usa ) was used to prepare all the solutions . \n ph meter from sevenmulti mettler toledo , switzerland , was used to prepare buffers . for sample handling , micropipettes ( \n carbonate buffer ( cb ; 0.05 m , ph 9.6 ) , phosphate buffered saline ( pbs ; 0.01 m , ph 7.4 ) , pbst ( pbs with tween 20 ) , and blocking solution ( bsa in pbs ) were made by the same protocol as described in our earlier paper . \n all the aflatoxin solutions were prepared in a glove box in a maintained inert ( n2 ) atmosphere . \n afm1 stock solution was prepared by dissolving the afm1 powder in 5% acn ( v / v ) in pbs at a concentration of 5 g/2 ml and stored at 28c . \n working standard solutions in the range of 1500 pg / ml were prepared by diluting the stock with 5% acn . \n afb1 stock solution 1000 g / ml was prepared by dissolving the crystalline afb1 in 5% acn ( v / v ) in pbs and stored at 4c . \n working afb1 standard solutions were prepared in the following concentrations : 1 , 6.25 , 12.5 , 25 , 50 , 100 , 250 , and 500 pg / ml by diluting the stock with 5% acn \n ( safety note : aflatoxins are highly carcinogenic and should be handled with extreme care . \n aflatoxin contaminated labware should be decontaminated with an aqueous solution of sodium hypochlorite ( 4% ) . ) \n the stock solution of rat monoclonal [ 1c6 ] 1ab , 100 g ( 1 mg / ml ) was diluted with 50 l of pyrogen free deionized water . \n the first fraction containing 40 l was stored at 20c . from the second fraction , \n the working antibody dilutions were prepared by serial dilution in double distilled water as 1 : 1000 , 1 : 2000 , and so forth and then added with equal volume of cb ( 1 : 1 ) . from the fitc labeled 2ab stock 1 mg ( 2 mg / ml ) solution , 100 l was diluted with 500 l of deionized water . \n working 2ab solution was prepared prior to the experiment by serial dilution in pbs as 1 : 1000 , 1 : 2000 , and so forth . \n crm - bd282 milk powder comprising zero level afm1 was reconstituted in the following manner . \n one g of crm - bd zero level milk powder was dissolved in 10 ml of warm pbs . \n the upper fatty layer was completely removed , and middle fat free portion was taken out . \n the decanted aqueous layer was filtered through a syringe filter using 0.22 micron filter paper . \n this was further diluted with pbs in 1 : 1 manner and used for analysis . \n these packaged milk samples were centrifuged , filtered , and treated in the same manner . \n 1ab was diluted to 1 : 16000 in cb and coated as 40 l / well . \n the plate was covered with parafilm and aluminium foil , kept at 4c for overnight , and washed 3 times by rinsing the wells with 40 l pbs . the remaining protein \n binding sites in the coated wells were blocked by adding 40 l of blocking solution for about 1 h at room temperature . \n the wells were washed twice with 40 l pbst . following this step , afm1 standard solution in the range 1500 \n pg / ml was mixed up ( at equal volume ) separately with optimized 2ab ( diluted to 1 : 64000 in pbs ) solution . \n this antigen - antibody mixture solution was then added as 40 l / well . \n the fitc labeled 2ab solutions were made by serial dilution from 1 : 1000 up to 1 : 128000 . \n figure 3 shows the optimization result obtained for fitc labeled 2ab with 1ab in fluorimetric assay . \n it was observed that fitc labeled antibody at 1 : 64000 dilution showed best signal ( 3.2 10 ) count when assayed with 1ab . \n the excitation time was 0.1 s. in order to achieve the optimal binding of analyte , the incubation time varied from 10 min to 180 min . \n figure 4 shows the optimization result of incubation time of afm1 and fitc labeled 2ab complex with capture 1mab . \n it is apparent from the graph that around 100120 min , the stable signal was obtained . \n so , the incubation time was chosen at 120 min in further experimental analysis . \n different concentrations of afm1 were tested both in pbs and in crm - bd282 zero level afm1 milk powder . \n calibration was studied in the range 1250 pg / ml by fluorimetric analysis . \n figure 5 shows graph of fluorimetric signals obtained for varying concentrations of afm1 in pbs and crm - bd282 . in both cases , decrease in the signal intensity was observed with the increase of [ afm1 ] . \n the fluorimetric assay could quantify the [ afm1 ] in an ultrasensitive manner with a lower limit of detection ( lod ) at 1 pg / ml . \n the analytical figures of merit of this afm1 assay by fluorimetric technique are given in table 2 . \n it is evident that aflatoxins such as afm1 , afm2 , afb1 , and afg1 have similar structures ( figure 1 ) . \n thus the capture antibody that recognizes its specific analyte may also partly recognize the other structural analogues . \n bearing this concept in mind , cr studies were carried out for afm1 , afb1 , afg1 , and afm2 recognition by the 1mab . \n the anti - afm1 mab was used as capture antibody , and fitc conjugated antibodies were used as 2ab for recognition of antigen - antibody ( ag - ab ) complex . \n the multianalysis of different aflatoxins using the cr with mab of afm1 was studied keeping the competitor concentration constant in all measurements . \n the standard solutions of different aflatoxins such as afm1 , afm2 , afb1 , and afg1 were prepared ranging from 1 to 500 pg / ml . \n these concentrations were mixed up with fitc labeled 2ab in equal volume ( total 40 l ) and added to four different rows of the microwell plate . \n after 2 h of incubation , washing was done to remove any unbound antigen or antibody . \n figure 6 shows the different aflatoxins specific recognition towards the mab of afm1 where concentration of competitor was plotted against b / b0 ( % ) . \n the cr study result ( figure 6 ) of fluorimetric assay shows that fitc labeled anti - afm1 antibody showed strong intensity when recognized afm1-ab complex . \n the cr of mab pair was determined in competition with tracer . for standard analyte ( for which cr is 100% ) , \n concentrations that result in 50% inhibition ( ic50 ) of the signal were obtained from calibrations and were used to compute the cr using the formula \n ( 1)cr(%)=ic50 value of standard analyteic50 value of cross reacting analyte100 . to evaluate the sensitivity of the elisa , the ic50 was obtained from the standard curves . \n the specificity of the elisa was evaluated by determining the cr with structurally related aflatoxins . \n the mab of afm1 was highly specific to afm1 and showed partial recognition towards its structural analogues afm2 and afb1 . \n figure 6 shows different aflatoxins specific recognition towards the mab of afm1 where concentrations of competitor were plotted against b / b0 ( % ) , where b0 is the maximum signal obtained in absence of analyte and b is the signal obtained in presence of analyte concentration . \n the ic50 values of afm1 and afm2 were obtained , but for afb1 and afg1 , ic50 could not be obtained as its cr with afm1 mab was not established . \n as indicated in table 3 , the mab of afm1 showed 23.2% cr with afb1 , approximately 50% with afm2 and showed negligible ( < 1% ) cr with afg1 . \n the standard curve of afm1 was used as reference in the elisa as indicated in figure 6 . \n the real sample analysis for two milk samples was carried out using mab against afm1 as receptors . \n the concentrations of afm1 , afm2 , afb1 , and afg1 were determined in the two milk samples using cr approach coupled with standard addition method . \n the wells were coated by mab of afm1 and incubated . then washing was done with pbs followed by blocking by bsa . in four different rows , \n the crm - bd282 zero level afm1 milk samples were spiked with 50 pg / ml of afm1 , afb1 , afg1 and afm2 , respectively . \n then milk samples 1 and 2 were added to the wells followed by fitc conjugated ab . \n after incubation of about 2 h and washing with pbs , they were analyzed by multiplate reader . \n the precision was determined by calculating the relative standard deviation ( r.s.d.% ) for the replicate measurements . \n the r.s.d.% and r.e.% were calculated by the following formulae : \n ( 2)r.e . \n ( relative error)% = measured valuetrue valuetrue value100 ; n=3,r.s.d . \n results , as listed in table 4 , showed an acceptable recovery in the range of 90%~101% , and r.s.d . was from 0% to 8% \n it was noted that the crm milk samples spiked with 50 pg / ml of afm1 showed 100% recovery . in s1 , \n also , s1 showed higher recovery than s2 . for afb1 , the recovery was found to be 81% , and when tested for s1 and s2 , it showed 100.8% and 93.6% , respectively . \n although in s1 analysis for afb1 , > 100% recovery was obtained , the concentration ( 400 pg / ml ) was much below the recommended level ( 2 g / l ) . for afg1 analysis , the recovery was 100.4% . in this case , the recovery for s1 and s2 was obtained as 92.6% and 93.6% , respectively . \n the mixture analysis was done by adding 50 and 25 pg / ml of afm2 and afb1 ( individually ) in varying amount of afm1 in the range 1100 pg / ml as shown in figures 7(a ) and 7(b ) . \n it was observed that , at 12.5 pg / ml of afm1 , the afm1 + afm2 ( 25 pg / ml ) mixture showed 4% and the afm1 + afm2 ( 50 pg / ml ) mixture showed 10% lesser signal intensity than that of only afm1 . \n similarly at 25 pg / ml of [ afm1 ] , the mixture of both afm1 + afm2 ( 25 and 50 pg / ml ) showed 2% and 4% decreases in signal intensity , respectively , as compared to only [ afm1 ] . at the eu cutoff limit or 50 pg / ml \n only 1.5% of decrease in signal intensity was obtained for afm1 + afm2 ( 25 pg / ml ) mixture . \n but when analyzed for afm1 + afm2 ( 50 pg / ml ) mixture , it showed 4% lesser signal when compared to only afm1 . at higher concentration of afm1 ( 100 pg / ml ) , \n the afm1 + afm2 ( 25 pg / ml ) showed 4% and the afm1 + afm2 ( 50 pg / ml ) showed 5% lesser signal intensity when compared to that of only afm1 . \n afm2 showed almost 50% cr with afm1 , and its presence as cocontaminant in the mixture resulted in small variation of 1.5 to 4% decrease at lower concentration ( 25 pg / ml ) , whereas at 50 pg / ml , the signal suppression was observed in the range of 4 to 10% variation . \n the mixture analysis was also carried out for afb1 and afm1 using anti - afm1 antibody as shown in figure 7(b ) . the standard calibration curve for afm1 \n was plotted against mixture of afm1 and afb1 ( 25 , 50 pg / ml ) . in this case , \n further decline in signal intensities was observed . at 12.5 pg / ml of [ afm1 ] , \n [ afb1 ] for 50 and 25 pg / ml showed 7.5% and 11.5% decrease in signal , respectively . for 25 and 50 \n pg / ml of [ afm1 ] , the afm1 + afb1 ( 25 pg / ml ) mixture showed the same decrease in signal of about 8% , but for afm1 + afb1 ( 50 pg / ml ) mixture it was 11% and 9.5% , respectively . at higher concentration of afm1 ( 100 pg / ml ) , \n the afm1 + afb1 ( 25 pg / ml ) and afm1 + afb1 ( 50 pg / ml ) mixtures showed 9 and 9.5% lesser intensities , respectively . \n the curve representing the mixture of [ afm1 ] with 100 pg / ml [ afb1 ] showed 12 and 10% less signal intensity of 25 and 50 pg / ml , respectively , when compared to only [ afm1 ] . in all the mixtures of afb1 , the signal suppression was observed in a higher order of 7.5 to 11.5% variation when compared to the mixture analysis of afm2 . \n this difference has occurred for the reason of difference in cr of afb1 with afm1 ( 23% ) which differs from 50% cr of afm2 with afm1 . \n this mixture analysis can play significant role in detecting and differentiating the presence of different aflatoxins which exist as cocontaminants found in the food commodities . based on their cr properties , afm1 , afm2 , and afb1 \n this work illustrates a simple and sensitive fluorimetric multianalyte microwell plate based immunoassay for aflatoxins . \n ultrasensitive analysis of afm1 was successfully carried out by the developed technique with lod as low as 1 pg / ml . \n elisa for multianalysis of different aflatoxins was investigated in pbs , certified reference material for afm1 and in real samples by fluorimetric technique in the microwell plate in presence of various types of competing analytes . \n structurally analogous aflatoxins were analyzed using the cr concept . from the assay , it was observed that afm2 showed the highest cr as compared with afb1 . \n the multianalysis of different aflatoxins was also verified by the mixture analysis of afm1 with afb1 and afm2 . \n assay on microwell plate allowed testing of highly toxic aflatoxins done with low sample volume and with easy handling . besides the sensitivity and minimal reagent consumption , such multianalysis would lead to simultaneous screening of multiple analytes of aflatoxins .", "role": "user" }, { "content": "a sensitive fluorimetric elisa was developed for the analysis of aflatoxins . \n the assay was performed in a 384 microwell plate , wherein high specificity monoclonal antibody against afm1 ( mab - afm1 ) was used as capture antibody and fitc conjugated secondary antibody was used for detection and quantification of the analyte . \n the linear range of the immunoassay was found to be 6.2550 pg / ml . \n afm1 as low as 1 pg / ml was detected by this method with assay volume 40 l . \n the multi - analysis of different aflatoxins was also investigated in the microwell plate , based on the cross - reactivity ( cr ) approach . \n real milk samples were tested along with certified reference material by standard addition method and recovery analysis was done . \n the mab - afm1 showed 23.2% cr with afb1 , 50% cr with respect to afm2 , and least cr towards afg1 ( < 1% ) . \n furthermore , mixture analysis of afm2 and afb1 was carried out at specific concentrations of afm1 . \n the advantages of this developed immunoassay are high sensitivity , high throughput , multianalyte detection , versatility , and ease of handling .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: the cbf / pebp2 binding site mutation was generated by pcr using as a template the 1.4-kb wild - type e subcloned into the xbai site of pbluescript ks+ ( 1.4ebs ) . \n pcr overlap extension was performed as described ( 38 ) using mutagenic oligonucleotides acorem ( agcaatgcatgacctttccaaccg ) and bcorem ( cggttggaaaggtcatgcattgct ) along with edra ( cttttaaaattctagcaagc ) and the reverse primer as outside primers . \n the final pcr product was digested with nsii and bamhi to generate a 170-bp fragment of e carrying the 3-bp change in e3 that eliminates cbf / pebp2 binding . \n the plasmid 1.4ebs was also digested with pfimi and nsii to obtain an adjacent 590-bp fragment of e. the two fragments were ligated together into pfimi and bamhi cut 1.4ebs . \n the structure of the resulting plasmid was determined by restriction mapping and dideoxynucleotide sequence analysis . \n the 1.4-kb emcore was excised from this plasmid with xbai and cloned into xbai - digested , phosphatase - treated pbluescript carrying the previously described enhancerless minilocus ( 13 ) . \n alui fragment of e ( e3,4 ) had been previously subcloned into psti and ecorv cut pbluescript ks+ . \n the insert was excised from this plasmid by digestion with bamhi and hindiii and the ends were blunted by treatment with the klenow fragment of escherichia coli dna polymerase i. this fragment was then ligated into xba i - digested , blunted , and phosphatase - treated pbluescript carrying the enhancerless minilocus . the structures of both minilocus constructs were confirmed by dideoxynucleotide sequence analysis . \n minilocus dna was purified as described previously ( 13 ) , and was microinjected into fertilized c57bl/6 sjl f2 eggs by the duke university comprehensive cancer center transgenic mouse shared resource . \n progeny tail dna samples were analyzed on southern blots as described previously ( 13 ) . \n copy number was determined by analysis of tail dna on a slot blot ( schleicher and schuell , keene , nh ) using a radiolabeled c cdna probe . \n hybridization signals were quantified relative to previously identified single copy integrants using a betascope ( betagen , waltham , ma ) . \n genomic dna preparation , pcr , gel electrophoresis , blotting onto nylon membranes ( hybond - n ; amersham , arlington heights , il or magna nylon ; micron separations inc . \n , westboro , ma ) , and hybridization with p - labeled probes were performed as described previously ( 13 ) . \n the amount of dna template used in pcr reactions ( 212 ng ) was adjusted based on the results of amplification using c primers to account for differences in transgene copy number and pcr efficiency between samples , so that all pcr signals were maintained in the linear range . \n tcr- minilocus pcr primers 1 ( vd1 ) , 2 ( vd2 ) , 3 ( jd1 ) , 4 ( jd3 ) , 5 ( cda ) , and 6 ( cdb ) , as well as the v1 , v2 , and c fragments used as probes to develop southern blots of pcr products or genomic restriction digests , were described previously ( 13 ) . \n these primers and probes allow detection of human tcr- minilocus sequences , but do not allow detection of endogenous murine tcr- locus sequences . \n quantification of pcr signals was accomplished using either a betascope or a phosphorimager ( molecular dynamics , sunnyvale , ca ) . \n the cbf / pebp2 binding site mutation was generated by pcr using as a template the 1.4-kb wild - type e subcloned into the xbai site of pbluescript ks+ ( 1.4ebs ) . \n pcr overlap extension was performed as described ( 38 ) using mutagenic oligonucleotides acorem ( agcaatgcatgacctttccaaccg ) and bcorem ( cggttggaaaggtcatgcattgct ) along with edra ( cttttaaaattctagcaagc ) and the reverse primer as outside primers . \n the final pcr product was digested with nsii and bamhi to generate a 170-bp fragment of e carrying the 3-bp change in e3 that eliminates cbf / pebp2 binding . \n the plasmid 1.4ebs was also digested with pfimi and nsii to obtain an adjacent 590-bp fragment of e. the two fragments were ligated together into pfimi and bamhi cut 1.4ebs . \n the structure of the resulting plasmid was determined by restriction mapping and dideoxynucleotide sequence analysis . \n the 1.4-kb emcore was excised from this plasmid with xbai and cloned into xbai - digested , phosphatase - treated pbluescript carrying the previously described enhancerless minilocus ( 13 ) . \n alui fragment of e ( e3,4 ) had been previously subcloned into psti and ecorv cut pbluescript ks+ . \n the insert was excised from this plasmid by digestion with bamhi and hindiii and the ends were blunted by treatment with the klenow fragment of escherichia coli dna polymerase i. this fragment was then ligated into xba i - digested , blunted , and phosphatase - treated pbluescript carrying the enhancerless minilocus . the structures of both minilocus constructs were confirmed by dideoxynucleotide sequence analysis . \n minilocus dna was purified as described previously ( 13 ) , and was microinjected into fertilized c57bl/6 sjl f2 eggs by the duke university comprehensive cancer center transgenic mouse shared resource . \n progeny tail dna samples were analyzed on southern blots as described previously ( 13 ) . \n copy number was determined by analysis of tail dna on a slot blot ( schleicher and schuell , keene , nh ) using a radiolabeled c cdna probe . \n hybridization signals were quantified relative to previously identified single copy integrants using a betascope ( betagen , waltham , ma ) . \n genomic dna preparation , pcr , gel electrophoresis , blotting onto nylon membranes ( hybond - n ; amersham , arlington heights , il or magna nylon ; micron separations inc . \n , westboro , ma ) , and hybridization with p - labeled probes were performed as described previously ( 13 ) . \n the amount of dna template used in pcr reactions ( 212 ng ) was adjusted based on the results of amplification using c primers to account for differences in transgene copy number and pcr efficiency between samples , so that all pcr signals were maintained in the linear range . \n tcr- minilocus pcr primers 1 ( vd1 ) , 2 ( vd2 ) , 3 ( jd1 ) , 4 ( jd3 ) , 5 ( cda ) , and 6 ( cdb ) , as well as the v1 , v2 , and c fragments used as probes to develop southern blots of pcr products or genomic restriction digests , were described previously ( 13 ) . \n these primers and probes allow detection of human tcr- minilocus sequences , but do not allow detection of endogenous murine tcr- locus sequences . \n quantification of pcr signals was accomplished using either a betascope or a phosphorimager ( molecular dynamics , sunnyvale , ca ) . \n the previously studied human tcr- gene minilocus is a 22.5-kb construct containing germline v1 , v2 , d3 , j1 , j3 , and c gene segments , along with a wild - type version of e within the j3c intron ( 13 ) ( fig . \n 1 a ) . the v1 and v2 coding segments carry mutations to prevent a rearranged transgene from encoding a tcr protein that might interfere with normal murine t cell development . thus , the minilocus serves as a phenotypically neutral in vivo reporter of vdj recombination . for this study \n , we initially constructed a new version of the minilocus , referred to as emcore , that carries a three basepair change in the e3 core sequence within e ( fig . 1 a ) . \n the identical mutation was previously shown to eliminate cbf / pebp2 binding to e3 in vitro , and to eliminate transcriptional activation by e in transient transfection experiments ( 25 ) . \n three transgenic founders , designated u , y , and z , were initially obtained . \n breeding experiments indicated that in each of founders u and z , the emcore minilocus was integrated at a single site in the mouse genome , whereas in founder y there were two independently segregating transgene integration sites . as a result , four different emcore transgenic lines ( u , z , y1 , y2 ) were established . as assessed by slot blot , \n the transgene copy numbers were : u , 8 copies ; z , 3 copies ; y1 , 1 copy ; and y2 , 2 copies . \n the single copy integrant in line y1 was truncated so as to delete 45 kb at the 3 end of the minilocus . \n this truncation leaves v , d , j gene segments , e and the first c exon intact , and as such , is not expected to have a significant effect on minilocus vdj recombination . \n analysis of wild - type and emcore minilocus vdj recombination was performed by pcr from thymus genomic dna templates , using specific v1 , v2 , j1 , and j3 primers ( primers 1 , 2 , 3 and 4 ; fig . \n previous studies have shown the wild - type minilocus to rearrange stepwise , first v to d , and then vd to j ( 13 ) . \n amplification with v and j1 primers yields 0.3 kb fragments that represent complete vdj rearrangements , and in addition , 1.2-kb fragments that represent the vd rearrangement intermediates ( fig . \n pcr reactions were also performed with a pair of c primers ( primers 5 and 6 ; fig . \n 1 c ) , to control for differences in transgene copy number and pcr efficiency between samples ; the amount of genomic dna template used in pcr reactions was typically adjusted to obtain similar c amplification signals in each sample . \n pcr products were detected and quantified by agarose gel electrophoresis followed by blotting and hybridization with appropriate p - labeled probes . in agreement with our previous studies ( 13 ) , \n quantification of pcr signals revealed amplification to be linear over a broad range of template concentrations ( fig . \n we analyzed the effect of the core site mutation on minilocus vdj recombination by comparing vd and vdj rearrangement levels in thymocytes from three previously characterized lines of mice carrying a minilocus with a wild - type e ( a , b , c ) ( 13 ) to thymocytes in the four lines of mice carrying the emcore minilocus ( fig . \n all e lines of mice carry single copy integrations of the minilocus . whereas the minilocus integrations in lines a and b include all relevant gene segments , the integration in line c is truncated at the 5 end and is missing the v1 gene segment . \n thus , lines a and b are informative for both v1 and v2 rearrangement , whereas line c is informative for v2 rearrangement only . as in previous studies , pcr analysis of vdj recombination in the e lines revealed high levels of 0.3-kb vdj rearrangement products in each case ( fig . \n 3 , a and b ) . levels of 1.2-kb vd rearrangement products were lower and more variable ( fig . \n as observed previously ( 13 ) , the enhancer - dependent vd to j step of transgene rearrangement occurs efficiently in each of the e lines . \n analysis of vdj recombination in the four emcore lines revealed quite different results . in three of the lines ( \n u , y1 , and z ) , 0.3-kb products representing vdj rearrangement were barely detectable , even though 1.2-kb vd rearrangement products were readily apparent ( fig 3 , a and b ) . in the fourth line ( y2 ) , \n vd and vdj rearrangement products were both detected at levels that were comparable to their representation in e lines . \n the analysis of a second animal in each line ( data not shown ) yielded quite similar results , arguing that these vdj recombination phenotypes are stable and reproducible characteristics of the individual transgenic lines . \n because pcr amplifications with the c primer pair and with the v1-j1 primer pair were shown to be linear over several orders of magnitude ( fig . \n 2 ) we were justified in quantifying the level of vdj recombination in the different lines by normalizing the v1-j1 pcr signal to the c pcr signal in each line . \n the levels of vdj recombination in lines u , y1 and z , each calculated as the mean of three independent determinations , were found to be 0.8 , 1.3 , and 0.3% , respectively , of the level in e line a , and 3.1 , 4.9 , and 1.2% , respectively , of the level in e line b ( table 1 ) . similar quantification revealed vdj recombination in line y2 to be 41.7% of the level in line a , and 159.8% of the level in line b ( table 1 ) . \n the conclusions drawn from pcr analysis were confirmed through analysis of v1-d3 and v1-d3-j1 rearrangements by genomic southern blot ( fig . \n e line a thymocytes displayed nearly undetectable germline v1 ( 1.0 kb ) , moderate v1-d3 rearrangement ( 0.9 kb ) , and substantial v1-d3-j1 rearrangement ( 1.7 kb ) . in accord with the pcr data , \n v1-d3-j1 rearrangement was not detected in lines u and z , even though transgene copy was higher in these lines than in e line a. importantly , v1d3 rearrangement was readily detected in both lines , and accounted for almost all of the v1 signal in line z. although the reduced sensitivity of genomic southern blot analysis as compared to pcr analysis does not allow an independent evaluation of the extent to which vdj recombination is reduced in lines u and z , the readily detectable v1-d3 rearrangement demonstrates that the ratio of vd to vdj rearrangement has been dramatically perturbed in these lines . as these results argue that the vd to j step of transgene rearrangement has been specifically inhibited , they provide strong support for the pcr data . \n also in accord with the pcr data , v1-d3 and v1-d3-j1 rearrangements were both detected in line y2 . \n thus , on the basis of both pcr and genomic southern blot analyses , we conclude that the enhancer - dependent step of minilocus rearrangement is dramatically and preferentially impaired in three of the four emcore transgenic lines , but occurs quite normally in the fourth line . \n these results are reminiscent of our previous work analyzing vdj recombination within a tcr- minilocus lacking e ( 13 ) or containing a disrupted binding site for c - myb ( 39 ) . in four of five transgenic lines carrying the minilocus construct lacking e , and in three of four transgenic lines carrying the minilocus construct with a disrupted binding site for c - myb , inhibition of the vd to j rearrangement step was almost complete . \n however , in each case one of the transgenic lines displayed higher levels of vd to j rearrangement . \n such heterogeneity in tcr- minilocus transgenic lines in which e has been eliminated or inactivated probably reflects the distinct properties of the different transgene integration sites . \n we propose that in e , emmyb , and emcore lines in which the vd to j step still occurs , the minilocus has integrated adjacent to active regulatory elements that partially or completely supplant the need for e. heterogeneity of this magnitude has not been observed in transgenic lines carrying an intact enhancer , as vd to j rearrangement is efficient in three of three e lines ( fig . \n 3 ) and four of four e lines ( 14 ) . on the basis of the phenotype displayed by the majority of emcore transgenic lines , \n we conclude that elimination of a functional cbf / pebp2 binding site within e has a dramatic effect on the ability of e to provide the regional accessibility to the vdj recombinase that is required for efficient vdj recombination in vivo . \n previous in vitro binding and transient transfection studies identified a functionally important binding site for c - myb that is within the e3 element and adjacent to the cbf / pebp2 binding site ( 27 ) , as well as two functionally important binding sites for gata-3 within the adjacent e4 element ( 40 , 41 ) . \n a 60-bp e3,4 fragment of e containing only these binding sites displays 2050% of the activity of the intact 1.4-kb e in transient transfection experiments ( 25 ) . \n since cbf / pebp2 ( this study ) and c - myb ( 39 ) were implicated as important regulators of vdj recombination in vivo , we asked whether the combination of cbf/ pebp2 , c - myb and gata-3 binding sites within e3 and e4 was sufficient to activate this process . \n therefore , the 60-bp e3,4 fragment of e was introduced into the tcr- gene minilocus in place of e ( fig . \n three transgenic founders were obtained and were used to generate independent lines of transgenic mice designated ja , je , and jg . \n slot blot analysis indicated transgene copy numbers of 2 , 1 , and 24 for ja , je , and jg , respectively . as in e line c , the single copy e3,4 line je is truncated such that it lacks v1 but retains v2 . \n analysis of wild - type e and e3,4 minilocus vdj recombination was performed by pcr as described above . \n all three e3,4 lines revealed dramatically reduced levels of vdj rearrangement as compared to e lines a , b , and c ( fig . 5 , a and b ) . in lines \n ja and je , vdj rearrangement was essentially undetectable , whereas in line jg , vdj rearrangement was detectable at reduced levels . nevertheless , vd rearrangement signals were readily detected by pcr in all three lines , and were detected at particularly high levels in line ja . \n quantification of v1-j1 and c pcr signals indicated that vdj rearrangement in lines ja and jg were reduced to 1.4 and 4.7% , respectively , of the level in e line a , and to 5.2 and 17.9% , respectively , of the level in e line b ( table 1 ) . \n analysis of v1-d3 and v1-d3-j1 rearrangements by genomic southern blot confirmed that essentially all copies of v1 were rearranged to d3 in line ja , but that rearrangement was blocked at this stage ( fig . \n although the low level of vdj rearrangement detected in line jg could not be confirmed due to both the limited sensitivity of detection and the presence of comigrating germline fragments in the tail dna control , the results for jg did suggest that pcr may have underestimated the level of v1-d3 rearrangement in this line . \n also of note is the significant reduction in transgene copy number in thymus relative to tail in this line ( fig . 4 and data not shown ) . \n this most likely results from the rearrangement of v1 in one copy of the tandemly arrayed transgene to d3 in another copy , with deletion of intervening copies . in summary , on the basis of the dramatic inhibition of vd to j recombination detected in both pcr and genomic southern blot analyses , we conclude that the combination of cbf/ pebp2 , myb , and gata-3 binding sites contained within e3 and e4 is not by itself capable of promoting the accessible chromatin configuration required for efficient minilocus vdj recombination . \n the previously studied human tcr- gene minilocus is a 22.5-kb construct containing germline v1 , v2 , d3 , j1 , j3 , and c gene segments , along with a wild - type version of e within the j3c intron ( 13 ) ( fig . \n 1 a ) . the v1 and v2 coding segments carry mutations to prevent a rearranged transgene from encoding a tcr protein that might interfere with normal murine t cell development . thus , the minilocus serves as a phenotypically neutral in vivo reporter of vdj recombination . for this study \n , we initially constructed a new version of the minilocus , referred to as emcore , that carries a three basepair change in the e3 core sequence within e ( fig . 1 a ) . \n the identical mutation was previously shown to eliminate cbf / pebp2 binding to e3 in vitro , and to eliminate transcriptional activation by e in transient transfection experiments ( 25 ) . \n three transgenic founders , designated u , y , and z , were initially obtained . \n breeding experiments indicated that in each of founders u and z , the emcore minilocus was integrated at a single site in the mouse genome , whereas in founder y there were two independently segregating transgene integration sites . as a result , four different emcore transgenic lines ( u , z , y1 , y2 ) were established . as assessed by slot blot , \n the transgene copy numbers were : u , 8 copies ; z , 3 copies ; y1 , 1 copy ; and y2 , 2 copies . \n the single copy integrant in line y1 was truncated so as to delete 45 kb at the 3 end of the minilocus . \n this truncation leaves v , d , j gene segments , e and the first c exon intact , and as such , is not expected to have a significant effect on minilocus vdj recombination . \n analysis of wild - type and emcore minilocus vdj recombination was performed by pcr from thymus genomic dna templates , using specific v1 , v2 , j1 , and j3 primers ( primers 1 , 2 , 3 and 4 ; fig . \n previous studies have shown the wild - type minilocus to rearrange stepwise , first v to d , and then vd to j ( 13 ) . \n amplification with v and j1 primers yields 0.3 kb fragments that represent complete vdj rearrangements , and in addition , 1.2-kb fragments that represent the vd rearrangement intermediates ( fig . \n pcr reactions were also performed with a pair of c primers ( primers 5 and 6 ; fig . \n 1 c ) , to control for differences in transgene copy number and pcr efficiency between samples ; the amount of genomic dna template used in pcr reactions was typically adjusted to obtain similar c amplification signals in each sample . \n pcr products were detected and quantified by agarose gel electrophoresis followed by blotting and hybridization with appropriate p - labeled probes . in agreement with our previous studies ( 13 ) , \n quantification of pcr signals revealed amplification to be linear over a broad range of template concentrations ( fig . \n we analyzed the effect of the core site mutation on minilocus vdj recombination by comparing vd and vdj rearrangement levels in thymocytes from three previously characterized lines of mice carrying a minilocus with a wild - type e ( a , b , c ) ( 13 ) to thymocytes in the four lines of mice carrying the emcore minilocus ( fig . \n all e lines of mice carry single copy integrations of the minilocus . whereas the minilocus integrations in lines a and b include all relevant gene segments , the integration in line c is truncated at the 5 end and is missing the v1 gene segment . \n thus , lines a and b are informative for both v1 and v2 rearrangement , whereas line c is informative for v2 rearrangement only . as in previous studies , pcr analysis of vdj recombination in the e lines revealed high levels of 0.3-kb vdj rearrangement products in each case ( fig . \n 3 , a and b ) . levels of 1.2-kb vd rearrangement products were lower and more variable ( fig . \n as observed previously ( 13 ) , the enhancer - dependent vd to j step of transgene rearrangement occurs efficiently in each of the e lines . \n analysis of vdj recombination in the four emcore lines revealed quite different results . in three of the lines ( \n u , y1 , and z ) , 0.3-kb products representing vdj rearrangement were barely detectable , even though 1.2-kb vd rearrangement products were readily apparent ( fig 3 , a and b ) . in the fourth line ( y2 ) , \n vd and vdj rearrangement products were both detected at levels that were comparable to their representation in e lines . \n the analysis of a second animal in each line ( data not shown ) yielded quite similar results , arguing that these vdj recombination phenotypes are stable and reproducible characteristics of the individual transgenic lines . \n because pcr amplifications with the c primer pair and with the v1-j1 primer pair were shown to be linear over several orders of magnitude ( fig . \n 2 ) we were justified in quantifying the level of vdj recombination in the different lines by normalizing the v1-j1 pcr signal to the c pcr signal in each line . \n the levels of vdj recombination in lines u , y1 and z , each calculated as the mean of three independent determinations , were found to be 0.8 , 1.3 , and 0.3% , respectively , of the level in e line a , and 3.1 , 4.9 , and 1.2% , respectively , of the level in e line b ( table 1 ) . similar quantification revealed vdj recombination in line y2 to be 41.7% of the level in line a , and 159.8% of the level in line b ( table 1 ) . \n the conclusions drawn from pcr analysis were confirmed through analysis of v1-d3 and v1-d3-j1 rearrangements by genomic southern blot ( fig . \n e line a thymocytes displayed nearly undetectable germline v1 ( 1.0 kb ) , moderate v1-d3 rearrangement ( 0.9 kb ) , and substantial v1-d3-j1 rearrangement ( 1.7 kb ) . in accord with the pcr data , \n v1-d3-j1 rearrangement was not detected in lines u and z , even though transgene copy was higher in these lines than in e line a. importantly , v1d3 rearrangement was readily detected in both lines , and accounted for almost all of the v1 signal in line z. although the reduced sensitivity of genomic southern blot analysis as compared to pcr analysis does not allow an independent evaluation of the extent to which vdj recombination is reduced in lines u and z , the readily detectable v1-d3 rearrangement demonstrates that the ratio of vd to vdj rearrangement has been dramatically perturbed in these lines . as these results argue that the vd to j step of transgene rearrangement has been specifically inhibited , they provide strong support for the pcr data . \n also in accord with the pcr data , v1-d3 and v1-d3-j1 rearrangements were both detected in line y2 . \n thus , on the basis of both pcr and genomic southern blot analyses , we conclude that the enhancer - dependent step of minilocus rearrangement is dramatically and preferentially impaired in three of the four emcore transgenic lines , but occurs quite normally in the fourth line . \n these results are reminiscent of our previous work analyzing vdj recombination within a tcr- minilocus lacking e ( 13 ) or containing a disrupted binding site for c - myb ( 39 ) . in four of five transgenic lines carrying the minilocus construct lacking e , and in three of four transgenic lines carrying the minilocus construct with a disrupted binding site for c - myb , inhibition of the vd to j rearrangement step was almost complete . \n however , in each case one of the transgenic lines displayed higher levels of vd to j rearrangement . \n such heterogeneity in tcr- minilocus transgenic lines in which e has been eliminated or inactivated probably reflects the distinct properties of the different transgene integration sites . \n we propose that in e , emmyb , and emcore lines in which the vd to j step still occurs , the minilocus has integrated adjacent to active regulatory elements that partially or completely supplant the need for e. heterogeneity of this magnitude has not been observed in transgenic lines carrying an intact enhancer , as vd to j rearrangement is efficient in three of three e lines ( fig . \n 3 ) and four of four e lines ( 14 ) . on the basis of the phenotype displayed by the majority of emcore transgenic lines , \n we conclude that elimination of a functional cbf / pebp2 binding site within e has a dramatic effect on the ability of e to provide the regional accessibility to the vdj recombinase that is required for efficient vdj recombination in vivo . \n previous in vitro binding and transient transfection studies identified a functionally important binding site for c - myb that is within the e3 element and adjacent to the cbf / pebp2 binding site ( 27 ) , as well as two functionally important binding sites for gata-3 within the adjacent e4 element ( 40 , 41 ) . \n a 60-bp e3,4 fragment of e containing only these binding sites displays 2050% of the activity of the intact 1.4-kb e in transient transfection experiments ( 25 ) . \n since cbf / pebp2 ( this study ) and c - myb ( 39 ) were implicated as important regulators of vdj recombination in vivo , we asked whether the combination of cbf/ pebp2 , c - myb and gata-3 binding sites within e3 and e4 was sufficient to activate this process . \n therefore , the 60-bp e3,4 fragment of e was introduced into the tcr- gene minilocus in place of e ( fig . \n three transgenic founders were obtained and were used to generate independent lines of transgenic mice designated ja , je , and jg . \n slot blot analysis indicated transgene copy numbers of 2 , 1 , and 24 for ja , je , and jg , respectively . as in e line c , the single copy e3,4 line je is truncated such that it lacks v1 but retains v2 . \n analysis of wild - type e and e3,4 minilocus vdj recombination was performed by pcr as described above . \n all three e3,4 lines revealed dramatically reduced levels of vdj rearrangement as compared to e lines a , b , and c ( fig . \n ja and je , vdj rearrangement was essentially undetectable , whereas in line jg , vdj rearrangement was detectable at reduced levels . nevertheless , vd rearrangement signals were readily detected by pcr in all three lines , and were detected at particularly high levels in line ja . \n quantification of v1-j1 and c pcr signals indicated that vdj rearrangement in lines ja and jg were reduced to 1.4 and 4.7% , respectively , of the level in e line a , and to 5.2 and 17.9% , respectively , of the level in e line b ( table 1 ) . \n analysis of v1-d3 and v1-d3-j1 rearrangements by genomic southern blot confirmed that essentially all copies of v1 were rearranged to d3 in line ja , but that rearrangement was blocked at this stage ( fig . \n although the low level of vdj rearrangement detected in line jg could not be confirmed due to both the limited sensitivity of detection and the presence of comigrating germline fragments in the tail dna control , the results for jg did suggest that pcr may have underestimated the level of v1-d3 rearrangement in this line . also of note \n is the significant reduction in transgene copy number in thymus relative to tail in this line ( fig . 4 and data not shown ) . \n this most likely results from the rearrangement of v1 in one copy of the tandemly arrayed transgene to d3 in another copy , with deletion of intervening copies . in summary , on the basis of the dramatic inhibition of vd to j recombination detected in both pcr and genomic southern blot analyses , we conclude that the combination of cbf/ pebp2 , myb , and gata-3 binding sites contained within e3 and e4 is not by itself capable of promoting the accessible chromatin configuration required for efficient minilocus vdj recombination . \n we previously documented enhancer - dependent vdj recombination within a human tcr- gene minilocus construct in transgenic mice ( 13 , 14 ) , and have now begun to address the mechanisms by which e exerts its effects on vdj recombination in this system . \n the data presented here indicates that a mutation that destroys the binding site for the transcription factor cbf / pebp2 within the e3 element of e seriously compromises the ability of e to activate the vd to j step of minilocus rearrangement . \n hence , by binding to e , this or a very closely related factor plays a crucial role in the developmental activation of minilocus rearrangement in vivo . \n we interpret the pattern of transgene rearrangement in the presence or absence of a functional e to indicate that a functional e is required to promote the accessibility of j gene segments to the vdj recombinase within the transgenic minilocus . \n although not directly proven , we infer that a functional e is also required to promote j gene segment accessibility , and hence vdj recombination , within the endogenous tcr- locus . \n our data therefore suggest strongly that cbf / pebp2 family transcription factors are likely to be important regulators of tcr- gene rearrangement at the endogenous tcr- locus in vivo . nevertheless , formal proof for this notion would require elimination of the e cbf / pebp2 binding site from the endogenous locus by homologous recombination . \n cbf / pebp2 was initially identified by virtue of its ability to bind to and activate transcription from polyoma virus enhancer and the long terminal repeats of murine t lymphotropic retroviruses ( 42 , 43 ) . \n functional cbf / pebp2 binding sites have been identified in the regulatory elements of several cellular genes expressed in either the t lymphoid or myeloid cell lineages ( 4448 ) , including the enhancers of all four tcr genes ( 30 , 3336 ) . \n cbf / pebp2 is actually a complex family of transcription factors , each of which is composed of a dna - binding subunit and an associated subunit ( 2931 ) . \n three distinct genes ( a , b , and c ) encode related subunits ( 30 , 4952 ) , a separate gene encodes a shared subunit ( 29 , 31 ) , and additional complexity is introduced by production of multiple and isoforms from the individual genes ( 2931 , 53 ) . \n thus , any one of a number of cbf / pebp2 species might be the crucial regulator of tcr- gene rearrangement in vivo . \n although recent analysis of cbf / pebp2 b null mice emphasizes a crucial role for this particular factor in hematopoiesis , the early lethality and pleiotropic effects of this mutation preclude any specific conclusions regarding a role in tcr- gene rearrangement ( 37 ) . \n a candidate regulator of tcr- gene rearrangement would have to be expressed as early as the cd4cd8 stage of thymocyte development , since the endogenous tcr- locus ( 54 , 55 ) and our transgenic minilocus ( 14 ) are both activated during this stage . \n notably , cbf / pebp2 a and b are both expressed at highest levels in the thymus and are both expressed in cd4cd8 thymocytes ( 56 ) . \n thus , both of these factors have expression patterns that would be consistent with a role in the activation tcr- gene rearrangement and expression in vivo . \n related studies using the transgenic minilocus approach have also implicated the transcription factor c - myb in the activation of tcr- gene rearrangement in vivo ( 39 ) . \n hence cbf / pebp2 and c - myb appear to synergize to activate tcr- gene vdj recombination in vivo , much as they were found to synergistically activate tcr- gene transcription in transient transfection studies ( 27 , 28 ) . \n nevertheless , our results indicate that the combination of cbf / pebp2 , myb , and gata-3 binding sites within e3 and e4 is not , by itself , sufficient to promote the accessibility required for efficient activation of vdj recombination within the tcr- gene minilocus . \n this suggests that additional cis - acting elements contained within the 1.4-kb e are crucial for this process . \n such elements may be contained within the 370-bp fragment of e found to contain maximal enhancer activity in transient transfection experiments . \n analyses of truncated forms of the enhancer suggest e2 , e5 , and e6 as candidate cis - acting elements of e that might individually or in combination increase the activity of the minimal enhancer by two- to threefold ( 24 , 25 ) . \n little is known about the identities of the factors that interact with these elements . nevertheless , it may be misleading to identify candidate determinants of e recombinational enhancer activity in a chromosomally integrated context in transgenic mice by extrapolating from those required for transcriptional enhancer activity in transient transfection experiments . \n for example , nuclear matrix attachment sites that flank e are irrelevant for transcriptional activity as measured in transient transfection experiments or in chromosomally integrated substrates in stably transfected cells , but are important for the induction of transcriptional activity and general sensitivity to dnase i digestion in a chromosomally integrated substrate in transgenic mice ( 57 ) . \n similarly sequences that flank the human adenosine deaminase gene enhancer are irrelevant for transcriptional activity in transient transfection experiments , but are required for high level expression and the establishment of enhancer dnase i hypersensitivity in transgenic mice ( 58 , 59 ) . \n it is therefore quite possible that cis - elements contained within the 1.4-kb e might not appear relevant for gene expression on the basis of transient transfection experiments , but might be critical for e induced accessibility and vdj recombination in transgenic mice . \n these additional cis - acting elements could be required for the stable assembly of cbf / pebp2 , c - myb , and gata-3 onto their e3 and e4 binding sites in a chromatin context . \n alternatively , e3 and e4 might by themselves be able to support the assembly of a stable nucleoprotein complex , but additional cis - acting enhancer elements might contribute independently to accessibility and vdj recombination . \n the hierarchy of assembly of nucleoprotein complexes at e , and the mechanisms by which assembled nucleoprotein complexes modulate regional chromatin accessibility and vdj recombination , will be important issues to address in future studies . \n structure and analysis of the e , emcore , and e3,4 transgenes . ( a ) schematic representations of the e and emcore minilocus recombination substrates includes coding exons ( filled boxes ) and protein binding sites within e ( open boxes ) . \n ( c ) primers used for analysis of minilocus rearrangement by pcr from genomic dna ( arrowheads ) . \n ( d ) depiction of pcr products generated from v1 rearrangements using primers 1 , 3 , and 4 . \n a similar set of pcr products are generated from v2 rearrangements using primers 2 , 3 , and 4 . \n serially diluted samples of thymus genomic dna from e line a were amplified by pcr using primers 1 and 3 or primers 5 and 6 , and southern blots were developed using radiolabeled v1 and c cdna probes . the v1d3-j1 ( solid line ) and c ( dotted line ) hybridization signals \n the results are expressed log hybridization signal in arbitrary units versus log dna concentration in g / ml . \n the second most concentrated dna sample in this experiment corresponds to the amount of dna used for analysis of single copy integrants in all subsequent experiments . \n ( a ) genomic dna from thymi of wild - type e mice from lines a , b , and c , and from emcore mice from lines u , y1 , z , and y2 were amplified by pcr using primers 5 and 6 ( top ) , primers 1 and 3 ( middle ) and primers 2 and 3 ( bottom ) . \n the mice analyzed were a-26 ( 3 wk old ) , b-29 ( 2 wk old ) , c-306 ( 6 wk old ) , u-19 ( 5 wk old ) , y1 - 83 ( 2 wk old ) , z-92 ( 3 wk old ) , and y287 ( 2 wk old ) . \n ( b ) genomic dna from the thymi of mice from lines a , u , z , and y2 were amplified by pcr using primers 5 and 6 ( top ) , primers 1 and 4 ( middle ) and primers 2 and 4 ( bottom ) . \n the mice analyzed were a-866 , u-339 , z-419 and y2 - 280 ( all 4 wk old ) . \n vdj rearrangement in e , emcore , and e3,4 transgenic lines the v1-d3-j1 and c hybridization signals were measured in three independent experiments . in each experiment , \n the v1-d3-j1 signal was normalized to the c signal , and the results are reported as the mean sd . \n vdj recombination expressed as a percentage of vdj recombination in line a. e , e3,4 , and emcore minilocus rearrangement analyzed by genomic southern blot . \n a southern blot carrying psti plus ecori digested tail ( germline control ) and thymus dna samples from e line a , e3,4 lines ja and jg , and emcore lines u , z , and y2 was developed with a radiolabeled 1.0 kb v1 genomic psti fragment as a probe . \n the mice analyzed were a-866 , ja-81 , jg-42 , u-339 , z-352 , and y2 - 280 ( all 4 wk old ) . pcr analysis of e and e3,4 minilocus rearrangement . \n genomic dna from thymi of wild - type e mice from lines a , b , and c , and from e3,4 mice from lines ja , je , and jg were amplified by pcr using primers 5 and 6 ( top ) , primers 1 and 3 ( middle ) and primers 2 and 3 ( bottom ) . \n the mice analyzed were a-765 ( 4 wk old ) , b-31 ( 8 wk old ) , c-114 ( 4 wk old ) , ja-81 ( 4 wk old ) , je101 ( 4 wk old ) , and jg-42 ( 4 wk old ) . \n ( b ) genomic dna from the thymi of mice from lines a , ja , je , and jg were amplified by pcr using primers 5 and 6 ( top ) , primers 1 and 4 ( middle ) and primers 2 and 4 ( bottom ) . \n the mice analyzed were a-866 , ja-81 , je-101 , and jg-42 ( all 4 wk old ) .", "role": "user" }, { "content": "we have analyzed transgenic mice carrying versions of a human t cell receptor ( tcr)- gene minilocus to study the developmental control of vdj ( variable / diversity / joining ) recombination . \n previous data indicated that a 1.4-kb dna fragment carrying the tcr- enhancer ( e ) efficiently activates minilocus vdj recombination in vivo . \n we tested whether the transcription factor cbf / pebp2 plays an important role in the ability of e to activate vdj recombination by analyzing vdj recombination in mice carrying a minilocus in which the e3 element of e includes a mutated cbf / pebp2 binding site . \n the enhancer - dependent vd to j step of minilocus rearrangement was dramatically inhibited in three of four transgenic lines , arguing that the binding of cbf / pebp2 plays a role in modulating local accessibility to the vdj recombinase in vivo . because mutation of the e3 binding site for the transcription factor c - myb had previously established a similar role for c - myb , and because a 60-bp fragment of e carrying e3 and e4 binding sites for cbf / pebp2 , c - myb , and gata-3 displays significant enhancer activity in transient transfection experiments , we tested whether this fragment of e is sufficient to activate vdj recombination in vivo . \n this fragment failed to efficiently activate the enhancerdependent vd to j step of minilocus rearrangement in all three transgenic lines examined , indicating that the binding of cbf / pebp2 and c - myb to their cognate sites within e , although necessary , is not sufficient for the activation of vdj recombination by e. these results imply that cbf / pebp2 and c - myb collaborate with additional factors that bind elsewhere within e to modulate local accessibility to the vdj recombinase in vivo .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: it has been estimated \n that about 4%-9% of dentigerous cysts occur in the first decade of life . \n keratocystic odontogenic tumor ( kcot ) presents most frequently in the \n second , third and fourth decades of life ( 54.2% ) with rare cases reported as early as \n the first , and as late as the ninth decade of life . \n removal of the entire \n cyst associated with the extraction of the impacted tooth is the main treatment to \n prevent recurrence of odontogenic cystic lesions . \n however , when there is a possibility \n of preservation and eruption of those teeth , conservative treatment should be the \n choice . \n treatment of kcots remains a controversial subject because of their great \n potential to recur . \n sometimes , the \n first surgical approach in kcot is decompression or marsupialization and when it gains \n reduced volume , enucleation has to be performed . \n this paper presents two cases of odontogenic lesions in children , one dentigerous cyst \n and one keratocystic odontogenic tumor , which were treated by marsupialization in order \n to preserve the associated permanent teeth . \n an 8-year - old boy was referred to the department of oral surgery with chief complaint \n of volume augmentation at the left side of mandible , pain and fever for about one \n week . \n panoramic radiograph revealed a unilocular radiolucent cystic lesion with \n sclerotic border associated lateral incisor , canine , first and second premolar \n crowns . \n after local bone aspiration and \n incisional biopsy , the histological diagnosis of dentigerous cyst was established \n ( figure 1 ) . \n hemorrhagic areas were also \n present . under local anesthesia , the patient was submitted to marsupialization after \n extraction of the primary molars ( figure 2a ) . \n the oral mucosa was sutured to the cyst capsule and iodoform gauze dressing was \n inserted within lesion cavity . \n medication gauze was changed every 5 days until the \n wound edges were epithelialized and afterwards an acrylic plug was inserted in order \n to keep wound opening and decompression . \n the parents were instructed to irrigate the \n cavity twice a day with saline solution and the acrylic plug was fitted when \n necessary , attending lumen reduction . \n the involved permanent teeth erupted naturally , without any traction \n forces ( figure 2b ) . \n second premolar assumed an \n impacted position over the first premolar probably because of dental arch space \n deficiency . \n one year \n after the first visit , the lesion had completely withdrawn , but the lateral incisor \n still remained displaced . \n a space - maintainer was installed and the patient was \n referred to orthodontic treatment ( figure 2c ) \n for correcting tooth position . \n the radiographic follow - up of 7 years showed no lesion \n recurrence ( figure 2d ) . \n photomicrograph of the lesion showing the cystic lesion lined by \n non - keratinized epithelium and hemorrhagic areas ( hematoxylin and eosin , \n original magnification x200 ) panel of panoramic radiographs . \n ( a ) unilocular osteolytic cystic lesion with \n sclerotic border associated to lateral incisor . \n ( b ) six - month \n followup radiographic image showing that teeth have erupted spontaneously . \n ( c ) \n one - year follow - up showing that teeth are still in eruption process . \n ( d ) seven - year radiographic image \n showed complete osteogenesis and teeth eruption a 10-year - old girl was referred to the oral surgery clinic for treatment of a cyst in \n the right side of the mandible found casually on a panoramic radiograph taken for \n orthodontic treatment planning . \n the patient came without complaint but oral \n examination revealed a slight swelling of alveolar mucosa related to a primary molar \n and canine . \n the panoramic radiograph showed a segmented radiolucent area in the right \n mandible body presenting a sclerotic border . \n inclusion and dislocation of the \n permanent canine , first and second premolars was also associated ( figure 3a ) . \n after local bone aspiration and \n biopsy , a diagnosis of keratocystic odontogenic tumor was established . \n the cyst \n capsule fragment presented a stratified epithelial lining with prominent columnar \n basal cell layer and parakeratinized daughter microcysts were scattered in the \n connective tissue wall ( figure 4 ) . in an \n attempt to maintain the permanent teeth , \n the patient was submitted to decompression \n procedure by extraction of the primary molars and insertion of iodoform gauze ( figure 3b ) . \n changing of medication gauze and \n acrylic plug were performed as described for case 1 . \n the permanent teeth went to \n natural eruption and 2 years after the first visit lesion had healed ( figure 3c ) . \n patient was submitted to orthodontic \n treatment and radiographic follow - up of 7 years showed no lesion recurrence ( figure 3d ) . \n ( a ) segmented osteolytic lesion in the right \n mandible body presenting a sclerotic border and inclusion and displacement of \n permanent canine , first and second premolars . \n ( b ) three - month follow - up image \n showing that permanent teeth went to natural eruption and decompression was \n maintained by iodoform gauze . \n ( c ) two - year follow - up image showing permanent \n teeth in spontaneous eruption . \n ( d ) seven - year follow - up image showing complete \n osteogenesis and teeth eruption photomicrograph of the lesion showing stratified epithelial lining with \n prominent columnar basal cell layer and parakeratin ( hematoxylin and eosin , \n original magnification x400 ) \n an 8-year - old boy was referred to the department of oral surgery with chief complaint \n of volume augmentation at the left side of mandible , pain and fever for about one \n week . \n panoramic radiograph revealed a unilocular radiolucent cystic lesion with \n sclerotic border associated lateral incisor , canine , first and second premolar \n crowns . \n after local bone aspiration and \n incisional biopsy , the histological diagnosis of dentigerous cyst was established \n ( figure 1 ) . \n hemorrhagic areas were also \n present . under local anesthesia , the patient was submitted to marsupialization after \n extraction of the primary molars ( figure 2a ) . \n the oral mucosa was sutured to the cyst capsule and iodoform gauze dressing was \n inserted within lesion cavity . \n medication gauze was changed every 5 days until the \n wound edges were epithelialized and afterwards an acrylic plug was inserted in order \n to keep wound opening and decompression . \n the parents were instructed to irrigate the \n cavity twice a day with saline solution and the acrylic plug was fitted when \n necessary , attending lumen reduction . \n the involved permanent teeth erupted naturally , without any traction \n forces ( figure 2b ) . \n second premolar assumed an \n impacted position over the first premolar probably because of dental arch space \n deficiency . \n one year \n after the first visit , the lesion had completely withdrawn , but the lateral incisor \n still remained displaced . \n a space - maintainer was installed and the patient was \n referred to orthodontic treatment ( figure 2c ) \n for correcting tooth position . \n the radiographic follow - up of 7 years showed no lesion \n recurrence ( figure 2d ) . \n photomicrograph of the lesion showing the cystic lesion lined by \n non - keratinized epithelium and hemorrhagic areas ( hematoxylin and eosin , \n original magnification x200 ) panel of panoramic radiographs . \n ( a ) unilocular osteolytic cystic lesion with \n sclerotic border associated to lateral incisor . \n ( b ) six - month \n followup radiographic image showing that teeth have erupted spontaneously . \n ( c ) \n one - year follow - up showing that teeth are still in eruption process . \n a 10-year - old girl was referred to the oral surgery clinic for treatment of a cyst in \n the right side of the mandible found casually on a panoramic radiograph taken for \n orthodontic treatment planning . \n the patient came without complaint but oral \n examination revealed a slight swelling of alveolar mucosa related to a primary molar \n and canine . \n the panoramic radiograph showed a segmented radiolucent area in the right \n mandible body presenting a sclerotic border . \n inclusion and dislocation of the \n permanent canine , first and second premolars was also associated ( figure 3a ) . \n after local bone aspiration and \n biopsy , a diagnosis of keratocystic odontogenic tumor was established . \n the cyst \n capsule fragment presented a stratified epithelial lining with prominent columnar \n basal cell layer and parakeratinized daughter microcysts were scattered in the \n connective tissue wall ( figure 4 ) . in an \n attempt to maintain the permanent teeth , \n the patient was submitted to decompression \n procedure by extraction of the primary molars and insertion of iodoform gauze ( figure 3b ) . \n changing of medication gauze and \n acrylic plug were performed as described for case 1 . \n the permanent teeth went to \n natural eruption and 2 years after the first visit lesion had healed ( figure 3c ) . \n patient was submitted to orthodontic \n treatment and radiographic follow - up of 7 years showed no lesion recurrence ( figure 3d ) . \n ( a ) segmented osteolytic lesion in the right \n mandible body presenting a sclerotic border and inclusion and displacement of \n permanent canine , first and second premolars . \n ( b ) three - month follow - up image \n showing that permanent teeth went to natural eruption and decompression was \n maintained by iodoform gauze . \n ( c ) two - year follow - up image showing permanent \n teeth in spontaneous eruption . \n ( d ) seven - year follow - up image showing complete \n osteogenesis and teeth eruption photomicrograph of the lesion showing stratified epithelial lining with \n prominent columnar basal cell layer and parakeratin ( hematoxylin and eosin , \n original magnification x400 ) \n authors related them to traumatic pathology \n or inflammatory processes in primary teeth . on the other hand , kcot , formerly known as okc and classified as a neoplasm by the world \n health organization ( who ) in 2005 , \n is a benign odontogenic tumor derived from the dental lamina that requires special \n surgical consideration because of its known aggressive behavior and high tendency to \n recur . \n kcots have been \n suggested as one of the major diagnostic criteria of nevoid basal cell carcinoma \n syndrome ( nbccs ) . \n the rate of \n recurrence varies enormously , from 0% to 62% , and the majority of \n recurrences occur within the first 5 years after treatment . \n most surgeons support complete removal with extension \n margins or careful curettage of the surrounding tissues . \n recurrence rates may be influenced by a variety of factors , including the length of the \n follow - up period , treatment modality , lesion size , histopathological presence of \n daughter cysts , and the number of cases investigated . \n marsupialization or decompressions are rather advisable treatments primarily in \n dentigerous cysts when we wish to preserve the cyst - associated teeth and promote their \n eruption even though it is difficult to reliably predict the tooth eruption . regarding treatment of an kcot , removal \n of the cyst including the associated tooth and surrounding \n some authors described the use of decompression and secondary \n enucleation as first line treatment option for kcot . \n furthermore when achieving a \n significant reduction of the lumen which can be confirmed trough radiographic imaging , a \n secondary cystectomy is justified to prevent recurrence of the lesion . \n the patients of \n this report were in the first decade of life and still had unerupted permanent teeth \n associated with the kcots . \n it was thus difficult to make a decision for an aggressive \n surgery over conservative management . in both cases , \n clinical judgment led to the preservation of the permanent teeth \n considering the age of the patients , the development of tooth roots and the possibility \n of that conservative therapeutic could relieve pressure from cyst 's fluid , allowing \n reduction of the intraosseous lesion and apposition of new bone to the cystic \n walls . \n some clinical and molecular studies have shown that the parakeratinized and \n orthokeratinized kcots were significantly different in molecular area as well as the \n recurrence rate ; orthokeratinized okcs had a lower recurrence rate than the \n parakeratinized okcs . \n although the \n okc presented in this paper is of parakeratinized type and exhibited daughter cysts \n observed within the lesion wall , which is a known factor of aggressiveness in kcots , the \n lesion did not recur after 7 years of follow - up . \n marsupialization has been considered as effective as a preliminary treatment for large \n kcots and it seems not to affect the recurrence tendency of this type of cyst . \n it is \n important to notice that the decompression procedure here was done without the \n supplementary enucleation neither or application of carnoy 's solution . \n reports also describe probable changes in growth characteristics when kcots are \n submitted to decompression that turns it rather less aggressive . \n some authors have observed epithelial dedifferentiation and loss of cytokeratin-10 \n production after a mean treatment time of 9 months , but they also suggested that the \n longitudinal follow - up of patients will determine whether this change is associated with \n lower rates of recurrence . sometimes after marsupialization / decompression eruption of the associated impacted teeth \n assumes an unusual position and orthodontic traction of the impacted tooth has to be \n performed if adequate space exists . \n in both cases , \n teeth that were present came to eruption spontaneously and orthodontic \n treatment was necessary to assure better alignment of teeth in dental arch . \n the left \n mandibular lateral incisor on the dentigerous cyst case assumed a lingual position and \n orthodontic treatment was important to correct the direction of eruption . \n although complete resolution of the lesions was achieved by a conservative approach , \n preserving anatomy and function , we agree with other authors that long - term follow - up is \n mandatory and can not be overlooked \n especially considering the odontogenic keratocystic tumor . \n both cases had similar radiographic aspects , both occurred in children , in the mandible \n body and were associated to the same group of unerupted permanent teeth . \n it is important \n to point out that only with an incisional biopsy and histological examination it is \n possible to accomplish a definitive diagnosis . \n the treatment choice should regard \n conservative managements with low morbidity particularly in young patients .", "role": "user" }, { "content": "dentigerous cyst ( dc ) is one of the most common odontogenic cysts of the jaws and \n rarely recurs . on the other hand , keratocystic odontogenic tumor ( kcot ) , formerly \n known as odontogenic keratocyst ( okc ) , \n is considered a benign unicystic or \n multicystic intraosseous neoplasm and one of the most aggressive odontogenic lesions \n presenting relatively high recurrence rate and a tendency to invade adjacent tissue . \n two cases of these odontogenic lesions occurring in children are presented . \n they were \n very similar in clinical and radiographic characteristics , and both were treated by \n marsupialization . \n the treatment was chosen in order to preserve the associated \n permanent teeth with complementary orthodontic treatment to direct eruption of the \n associated permanent teeth . at 7-years of \n follow - up , none of the cases showed \n recurrence .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: two groups of children < 5 years of age hospitalized for acute diarrhea were studied : 1 ) 285 children enrolled from march 2000 to february 2001 at 3 main hospitals of mexico city , instituto mexicano del seguro social ( imss ) ; and 2 ) 145 children enrolled from february to october 2004 at the children 's hospital in villahermosa , tabasco , hospital del nio , secretara de salud ( ss ) . \n the institutional review boards of imss and ss approved these studies , and parental informed consent was obtained for each patient . \n children were included if they had 3 loose stools in 24 hours or an episode of bloody diarrhea . \n a total of 430 mexican children hospitalized for acute diarrhea ( < 14 days ) were included , 222 ( 52% ) were male and 321 ( 77% ) were 2 years of age . \n stool diagnostic evaluations were done by standard laboratory procedures , including culture for salmonella spp . \n , vibrio cholerae , and campylobacter spp . ; enzyme - linked immunosorbent assay or latex agglutination test for rotavirus ; and microscopy for entamoeba histolytica , cryptosporidium parvum , cyclospora cayetanensis , isospora spp . , and giardia lamblia . \n in addition , from all 430 stool samples , 5 lactose - fermenting colonies and 5 sorbitol - nonfermenting colonies with shapes resembling that of e. coli were selected from standard and sorbitol macconkey agar plates , respectively and speciated biochemically . \n a total of 2,010 e. coli strains from 430 patients were selected , and all were analyzed by a multiplex pcr ( 3 ) that detects the following pathogenic genes : heat - stable and heat - labile enterotoxins ( st , lt ) for etec , intimin ( eaea ) and bundle - forming pilus ( bfp ) for epec , shiga toxin 1 and 2 ( stx1 , stx2 ) and intimin ( eaea ) for stec , and invasion - associated loci ( ial ) for eiec . \n stec from patients were further characterized by the expression of the o157 lipopolysaccharide antigen and enterohemolysin gene ( hlya ) by using latex particle agglutination kit ( oxoid limited , basingstoke , uk ) and pcr , respectively . \n moreover , all e. coli strains from the villahermosa study were analyzed by a second multiplex pcr that detects 3 plasmidborne virulence genes ( aap , aggr , and aata ) from eaec ( 4 ) . \n both pcrs were developed at the department of molecular biomedicine , centro de investigacin y de estudios avanzados ( cinvestav ) . in the present study , pathogenic eaec were defined as those harboring the 3 plasmidborne genes , aap , aggr , and aata , as previously described ( 4 ) . \n this definition may be stringent , but for the antimicrobial susceptibility analysis , we wanted to include only pathogenic de when possible . \n finally , e. coli strains positive for any de gene were analyzed for their antimicrobial susceptibility by disk diffusion , according to the clinical and laboratory standards institute ( formerly nccls ) guidelines ( 5 ) . \n de were identified in 62 ( 14% ) of 430 patients , the second highest proportion after that of rotavirus ( 41% ) . \n as shown in table 1 , etec was the most prevalent de group isolated in patients , closely followed by eaec ( only characterized in the villahermosa study ) and then by atypical epec ( aepec [ eaea+ bfp ] ) . \n most stec strains were stx2 + or stx1 + eaea+ , none expressed the o157 lipopolysaccharide antigen , and only 1 contained the hlya gene . \n * etec , enterotoxigenic e. coli ; eaec , enteroaggregative e. coli ; aepec , atypical enteropathogenic e. coli ; stec , shiga toxin producing e. coli ; epec , enteropathogenic e. coli ; eiec , enteroinvasive e. coli . \n all diarrheogenic e. coli strains isolated from patients with diarrhea ; in general , 5 e. coli strains were isolated from each patient . \n antimicrobial resistance patterns for patients that had de included 65% resistant to trimethoprim - sulfamethoxazole ( tmp - smx ) and 73% to ampicillin ( table 2 ) . \n the antimicrobial resistance patterns for the strains were similar to the ones described above for the patients . \n thus , of the 170 strains 105 ( 62% ) were multidrug resistant , 145 ( 85% ) were resistant to tetracycline , 124 ( 73% ) to ampicillin , 127 ( 75% ) to tmp - smx , 29 ( 17% ) to chloramphenicol , 4 ( 2% ) to gentamicin , and none to ciprofloxacin and cefotaxime . \n comparison of resistance patterns between patients belonging to different de groups showed that aepec was significantly less resistant ( p<0.05 , chi - square test ) to ampicillin and tmp - smx than etec and eaec . * \n one stec ( 9% of stec or 2% of all isolates ) was resistant to gentamicin ; all other isolates were susceptible . \n tet , tetracycline ; amp , ampicillin ; tmp - smx , trimethoprim - sulfamethoxazole ; chlor , chloramphenicol ; mdr , multidrug resistant ; etec , enterotoxigenic e. coli ; eaec , enteroaggregative e. coli ; aepec , atypical enteropathogenic e. coli ; stec , shiga toxin producing e. coli ; epec , enteropathogenic e. coli ; eiec , enteroinvasive e. coli . \n diarrheogenic e. coli prototypes cause high rates of persistent diarrhea ( 68 ) , which has been associated with malnutrition , growth impairment , and death , in developing countries ( 1,6,8 ) . from the 62 patients with de , \n etec was the most prevalent group ( 27% of cases ) , showing that etec continues to be a major health problem in developing countries ( 6 ) . \n eaec accounted for 26% of cases , although it was characterized at only 1 site , and a stringent definition of pathogenic eaec was used . \n eaec prevalence may be even higher , and it may be responsible for much acute diarrhea requiring hospitalization in children , as recently shown in the united states ( 2 ) . unexpectedly , \n 21% of patients harbored aepec strains ; the pathogenic role of this emerging e. coli group is still unclear , but it has been associated with acute ( 9 ) and persistent diarrhea ( 10 ) . in addition , those aepec strains showed significantly less resistance ( p<0.05 , chi - square test ) to ampicillin and tmp - smx than etec and eaec strains , which suggests that aepec strains may have recently been acquired in mexico . finally , 18% of patients harbored stec non - o157 strains , showing its role in acute diarrhea that requires hospitalization in mexico . together these observations highlight the role of de in children 's diarrhea that requires hospitalization and stress the importance of seeking de in children 's stools by using multiplex pcr technology . \n we have also shown that specific and sensitive multiplex pcr technology ( 3,4 ) that recognizes a diversity of loci in e. coli may be cost effective , which would allow clinical laboratories worldwide to identify these pathogens . since some de infections appear indistinguishable from viral gastroenteritis , isolation and identification of de strains could allow caretakers to provide appropriate treatment for pathogen - specific illness . oral rehydration therapy ( ort ) in children with dehydrating forms of diarrhea has reduced death rates worldwide . \n ort , however , does not shorten duration of illness and shedding , whereas antimicrobial therapy may be of value for some forms of de diarrhea ( 11 ) . \n antimicrobial therapy may be indicated in children with de diarrhea that is promptly identified and in children with persistent diarrhea . \n we have shown that most de strains that cause diarrhea in hospitalized children in mexico are resistant to tmp - smx and ampicillin , drugs commonly used to treat pediatric diarrhea . \n this resistance pattern is an emerging problem for de strains isolated from children in other developing countries ( 12 ) and for other enterobacteria worldwide ( 1214 ) . \n all strains were sensitive to ciprofloxacin and cefotaxime ; however , ciprofloxacin and other quinolones are not approved for children because of the risk of damage to immature joints ( 14 ) , and most parenteral third - generation cephalosporins ( e.g. , cefotaxime ) are administered only in a hospital setting . \n these results show the need for new , affordable , and safe oral antimicrobial drugs to treat enterobacterial infections in children .", "role": "user" }, { "content": "diarrheogenic escherichia coli isolates from 45 ( 73% ) of 62 hospitalized patients were resistant to common antimicrobial drugs . \n sixty - two percent were multidrug resistant , and > 70% were resistant to trimethoprim - sulfamethoxazole and ampicillin . \n ciprofloxacin and cefotaxime were uniformly active . \n effective and safe oral agents are needed to treat children with bacterial diarrhea .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: osteoblastoma ( ob ) is a benign tumor of bone characterized by osteoid and bone formation with the presence of numerous osteoblasts . \n this tumor was first described by jaffe and mayer in 1932 . the current term benign osteoblastoma was proposed by jaffe and lichtenstein in two separate reports in 1956 . \n , osteoblastoma constitutes about 1% of all primary bone tumors . in approximately 15% of cases \n it is found in the maxillofacial skeleton , with a greater frequency occurring in the mandible . , borello and sedano reported the first case of osteoblastoma involving the jaws . \n very few cases of osteoblastomas occurring in the jaws have been reported in the literature . to the best of our knowledge , since the original description by jaffe and mayer in 1932 , \n about 108 well documented examples of osteoblastoma arising both in the maxilla or mandible have been reported in the english literature till date . \n here we report one such rare case of ob occurring in posterior mandible and a brief review of english literature . \n a 25-year - old man presented with chief complaint of a painless swelling in mandibular lower left back region since 3 years . \n the lesion was small and increased in the past 3 years to the present size . \n the clinical examination revealed a firm palpable hard mass , which was fixed to the underlying bone . \n the swelling is noted on the left posterior part of the ramus of the mandible with no facial symmetry . \n intra - oral examination showed a mass of about 5 4 cm in diameter and was well circumscribed . \n based on the patient history and clinical findings , a provisional diagnosis of cementoblastoma , osteoblastoma , ossifying fibroma was given . \n orthopantomogram showed a round to oval radio opaque mass with a radiolucent border at the apex of left mandibular 1 molar ( figure 1 ) . \n the lesion was excised under general anaesthesia and the surgical specimen comprised of both tooth and a hard tissue mass attached to it ( figure 2 ) . \n histologically , h and e stained sections revealed both hard and soft tissue mass mainly comprising of bone arranged both in trabacular as well as lamellar pattern with new bone formation and osteoid matrix in a highly vascular connective tissue stroma ( figure 3a and figure 3b ) . \n the lamellar pattern mainly consists of calcified cellular inclusive mainly osteocytes . based on histopathological findings , the diagnosis of osteoblastoma was confirmed . \n figure 1orthopantomogram ( opg ) showing a round to oval radio opaque mass with a radiolucent border at the apex of left mandibular 1 molar . \n orthopantomogram ( opg ) showing a round to oval radio opaque mass with a radiolucent border at the apex of left mandibular 1 molar . \n figure 3a ) photomicrograph showing photomicrograph showing osteoid deposition with osteoblastic rimming and rich vascularity ; b ) irregular woven bone in lace like pattern within a loose fibrocellular and vascular connective tissue stroma . \n a ) photomicrograph showing photomicrograph showing osteoid deposition with osteoblastic rimming and rich vascularity ; b ) irregular woven bone in lace like pattern within a loose fibrocellular and vascular connective tissue stroma . \n osteoblastoma is a rare benign neoplasm of bone , recognized as separate entity and distinguished from osteoid osteoma . \n though osteoblastoma is considered as benign , the true nature of this lesion is unknown . \n , smith et al . , have regarded this entity as an abnormal local response of the tissues to injury , or even possibly as a localized alteration in bone physiology , rather than as a true neoplasm . \n osteoblastoma seldom involves the jaws and very few cases in the literature have been reported to occur in the jaws . \n osteoblastomas of jaws are either medullary or periosteal and not cortical which are common in extragnathic sites . \n the mandible is affected more often than the maxilla with most mandibular lesions occurring in the body . \n gordon et al have showed that 59% of osteoblastomas occur in men and 41% in women . \n mandible is affected more often than maxilla and most of the mandibular lesions tend to occur in the body region . \n the systematic review of the english - language medical literature of ob of jaws showed only 108 cases published as various case reports as well as reviews . \n pubmed and medline search was done using the keywords osteoblastoma , benign osteoblasoma , bone tumors and osteoblastoma of jaws for the review of literature . the summary of clinical details such as age , gender , site and symptoms and radiographic findings of the previous cases of ob of jaws in the literature review are enlisted in table 1 . \n previous literature reviews had left out few cases in their study and the clinical data of the same had variations . in the present review , \n an additional 13 cases have been included after the recent review of literature . out of 108 cases excluding the present cases , the age range of patient was from 3 years to 78 years with the mean age of 2223 years . \n the male to female ratio is almost equal ( 47% to 53% ) with slight increase in females . \n about 10% of cases are asymptomatic and 5% cases have been reported without any details about the nature disease . \n eighty - one cases occurred in the mandible ( 74% ) and twenty - nine cases are associated with the maxilla ( 26% ) . \n of 110 cases , only 54 cases ( 49% ) occurred in the posterior region and 9 cases occurred in the anterior region of both the jaws . \n however , 47 cases ( 43% ) have not stated the location of occurrence the lesion in the jaws . \n forty - three cases ( 39% ) had mixed radiolucency and opacities with poorly and well defined borders . \n radiolucent lesions were noted in 28 cases ( 25% ) and 22 cases ( 20% ) had radiopaque lesions . \n the details of radiographic findings in rest of the 12 cases ( 11% ) were not available . \n all the above discussed data is summarized in table 2 . \n table 1details of english literature review of benign osteoblastoma cases.caseauthorsyearage*genderlocationsymptomradiographic1capodiferro , et al.200516fmandiblepainful swellingmixed poorly defined2200510mmandiblepainful swellingmixed poorly defined3200520fmandiblepainful swellingmixed poorly defined4200521mmandiblepainful swellingmixed \n poorly defined5rawal , et al.200630fparasymphsis body of mandiblepainful swellingradiolucent well - defined6200631fbody of mandiblepainful swellingradiolucent well - defined7200616mmaxilla , canine premolarpainful swellingradiolucent well - defined8200629fbody of mandiblepainful swellingmixed poorly defined9200618fbody of mandiblepainful swellingnon - description10200615fbody of mandiblepainless swellingradiolucent well - defined11200678mbody of mandiblepainful swellingradiopaque12angiero , et al.20068mright posterior maxillapainless swellingmixed poorly defined13200624mleft posterior mandiblepainless swellingmixed poorly definedmodified and updated from alvares capelozza , et al . and jones , et al . \n f , female ; m , male.*age in years . \n modified and updated from alvares capelozza , et al . and \n table 2summary of 108 cases of osteoblastoma of the jaws reported in english literature till date.age age range3 to 78 mean age22.23gendermalen=51(47.22% ) age range5 to 78 mean age22.04femalen=57(52.78% ) age range3 to 53 mean age22.42location \n mandible81(73.64% ) maxilla29(26.36% ) posterior region54(49.09% ) anterior region09(8.18% ) not stated47(42.73% ) \n left side36(32.73% ) right side18(16.36% ) not stated56(50.91%)symptom asymptomatic11(10% ) swelling23(20.91% ) pain / tender70(63.64% ) not stated6(5.45%)radiographic description radiolucent28(25.45% ) radiopaque22(20% ) ground glass5(4.55% ) mixed43(39.09% ) not stated11(10% ) no finding1(0.90% ) \n desouza and frost reviewed 24 cases of osteoblastoma , dividing their cases into three categories : i ) cortical osteoblastoma - synonymous with osteoid osteoma , showing a circumscribed appearance and striking perifocal bone reaction ; ii ) spongious osteoblastoma - synonymous with little bone reaction ; iii ) periosteal osteoblastoma - synonymous with poorly circumscribed , little bone reaction . \n smith et al . , have compared the osteoblastoma in gnathic and extragnathic sites , concluding that the lesion has similar clinical , radiologic and histologic features in both instances . \n osteoblastoma of the jaws when is associated with the roots of teeth , it is difficult to distinguish from cementoblastoma . \n abrams et al . reported that the histologic similarities of cementoblastoma , osteoid osteoma , and benign osteoblastoma suggesting a close relationship among these three conditions . \n the attachment of the tumor to the roots of teeth should not be used as a hallmark for the diagnosis of cementoblastoma as osteoblastoma in the tooth - bearing area may envelop the roots of the involved teeth . however , the broad trabacular regions with limited cellularity seem to be a prominent feature , possibly unique to cemetoblastoma . furthermore , reversal lines that may impart a mosaic pattern to the calcified portion are a feature of cementoblastoma . \n radiation should be considered only if surgical removal is not possible and there is evidence of continued aggressive behavior or multiple recurrences . \n ob has to be differentiated from other bone producing lesions such as osteoid osteoma , osteosarcoma , cementoblastoma , ossifying fibroma etc . \n yang c and qiu wl have reported 24 new cases of osteoblastoma in the maxilla and mandible . \n osteoblastoma has to be differentiated from other similar bone producing lesions like osteoid osteoma , osteosarcoma , cementoblastoma , ossifying fibroma etc for correct diagnosis . \n many bone - producing lesions possess some clinical , radiographic or histopathological similarity to osteoblastoma . \n this helps in correctly diagnosing and helps in adequate management of this rare entity , giving a good prognosis .", "role": "user" }, { "content": "benign osteoblastoma ( ob ) is a rare tumor of bone representing less than 1% of all tumors of the maxillofacial region . \n vertebral column , sacrum , long bones , and calvarium are more frequent sites of this tumor . \n clinically , patients present with pain and swelling . \n histologically , contain a well vascularized , osteoblastic connective tissue stroma and occasionally , osteoclasts along with osteoid and varying degrees of calcification , as well as immature bone may also be noted . \n the main aim of this report is present a case of ob occurring in the mandible and a brief review of english medical literature of this tumor . \n many bone - producing lesions possess some overlapping clinical , radiographic or histopathological findings similar to osteoblastoma . \n understanding and correlating all features helps in correct diagnosis and adequate management of this rare entity . \n hence , osteoblastoma has to be differentiated from other bone lesions for correct diagnosis .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: surgical resection of thoracic dumbbell tumors is occasionally challenging because it necessitates surgical approach to three compartments ( intraspinal , foraminal , and mediastinal ) . \n although several surgical approaches such as single or multiple staged , combined laminectomy and open thoracotomy , or single - staged posterior wide laminectomy with instrumentation have been introduced , there has been no definite standard technique until now1,2,9,11 ) . currently , combined posterior laminectomy and video - assisted thoracoscopic surgery ( vats ) has been introduced as an alternative method to remove thoracic dumbbell tumor in several case reports5,7,10,12 ) . here \n , we describe a one - stage posterior minimal laminectomy and vats technique as a less invasive technique to remove thoracic dumbbell tumor and discuss the technique s usefulness and limitations . \n between 2009 and 2015 , one - stage posterior minimal laminectomy and vats was performed to remove thoracic dumbbell tumor in seven patients ( two men and five women ) . \n the mean age of the patients was 43 years ( ranged from 30 to 57 ) , and the level of tumors varied from t2/3 to t12/l1 ( table 1 ) . \n the first step in posterior hemilaminectomy is a posterior midline incision of 5 cm in the prone position . \n next , hemilaminectomy is performed preserving the minimal lateral half facet joint with a high speed drill . \n after the thecal sac and intraspinal tumor mass are exposed , the involved nerve root is identified . \n the intraspinal mass is removed by a piecemeal technique and a small amount of tumor material is sent for frozen biopsy , after which pathological findings are identified . \n when the thecal sac is decompressed and the involved nerve root is resected , the normal proximal nerve root remains . in most cases , \n thoracic dumbbell tumor does not invade the intradural space , and the normal proximal part of the nerve root can be identified . after meticulous bleeding control , the wound is closed . after the patient s position was changed to lateral decubitus , an initial 1.1 cm incision was made in the 7th8th intercostal space ( ics ) on the mid - axillary line . \n thoracoscope ( 30 direction and 10 mm diameter ) was introduced to inspect the pleura . \n the other ports were inserted through the 3rd4th ics in the anterior axillary line and 6th7th ics in the posterior axillary line to make triangular configuration . \n after the thoracoscope was reinserted through the port in the 3rd4th ics in anterior axillary line , the instruments were reemployed through the other ports for grasping and dissection of tissues . \n after the thoracoscope was reinserted through the port in the 3rd4th ics in anterior axillary line , the instruments were reemployed through the other ports for grasping and dissection of tissues . \n after division of the parietal pleura around the tumor , the tumor was usually dissected from the bottom , preventing injury of the intercostal artery and vein . if the intercostal artery and vein were drained to the tumor or interrupted the dissection , they were divided using endo clips . \n the tumor was extracted through the port in the 3rd4th ics in the anterior axillary line using an endobag ( fig . \n 1 ) . the tumor surface and involved nerve root , which were resected by intraspinal approach , were identified to confirm total tumor resection . \n between 2009 and 2015 , one - stage posterior minimal laminectomy and vats was performed to remove thoracic dumbbell tumor in seven patients ( two men and five women ) . \n the mean age of the patients was 43 years ( ranged from 30 to 57 ) , and the level of tumors varied from t2/3 to t12/l1 ( table 1 ) . \n the first step in posterior hemilaminectomy is a posterior midline incision of 5 cm in the prone position . \n next , hemilaminectomy is performed preserving the minimal lateral half facet joint with a high speed drill . \n after the thecal sac and intraspinal tumor mass are exposed , the involved nerve root is identified . \n the intraspinal mass is removed by a piecemeal technique and a small amount of tumor material is sent for frozen biopsy , after which pathological findings are identified . \n when the thecal sac is decompressed and the involved nerve root is resected , the normal proximal nerve root remains . in most cases , \n thoracic dumbbell tumor does not invade the intradural space , and the normal proximal part of the nerve root can be identified . after meticulous bleeding control , the wound is closed . after the patient s position was changed to lateral decubitus , an initial 1.1 cm incision was made in the 7th8th intercostal space ( ics ) on the mid - axillary line . \n thoracoscope ( 30 direction and 10 mm diameter ) was introduced to inspect the pleura . \n the other ports were inserted through the 3rd4th ics in the anterior axillary line and 6th7th ics in the posterior axillary line to make triangular configuration . \n after the thoracoscope was reinserted through the port in the 3rd4th ics in anterior axillary line , the instruments were reemployed through the other ports for grasping and dissection of tissues . \n after the thoracoscope was reinserted through the port in the 3rd4th ics in anterior axillary line , the instruments were reemployed through the other ports for grasping and dissection of tissues . \n after division of the parietal pleura around the tumor , the tumor was usually dissected from the bottom , preventing injury of the intercostal artery and vein . \n if the intercostal artery and vein were drained to the tumor or interrupted the dissection , they were divided using endo clips . \n the tumor was extracted through the port in the 3rd4th ics in the anterior axillary line using an endobag ( fig . \n 1 ) . the tumor surface and involved nerve root , which were resected by intraspinal approach , were identified to confirm total tumor resection . \n the mean operative time was 331 minutes ( range 255 to 385 min ) , with estimated blood loss ( ebl ) of 110 to 930 ml ( mean , 348 ml ) . in six patients , \n in one patient , the ebl was 930 ml because the pathological finding was unexpectedly hemangioma . \n one day after operation , the patient with atelectasis underwent bronchoscopy and atelectasis was immediately improved . in a patient with a dumbbell tumor at t2/3 , facial anhidrosis occurred on the affected side due to sympathetic trunk injury , and this conditions still persisted after two years . \n final pathologic findings included schwannoma in three patients , neurofibroma in three , and hemangioma in one ( table 1 ) . \n the postoperative follow - up period was 3 to 58 months ( mean : 18.5 months ) . \n there was no tumor recurrence , spinal instability or pain in any patients upon final follow - up . \n a 55-year - old female ( case 4 ) admitted to our hospital with left thoracic radiating pain . \n mri revealed a dumbbell shaped tumor with a neuroforaminal extension in the left paravertebral space and posterior mediastinum at t2/3 ( fig . \n , the tumor was found to not originate from the nerve root and showed unexpected bleeding during intraspinal piecemeal removal . \n after complete removal of the intraspinal tumor , the exiting t2 nerve root was sacrificed for tumor extraction during vats . after posterior approach , vats was performed through three ports and the mediastinal mass was found to be ovoid with a diameter of 3 cm diameter in thoracoscopic view and appeared to be hypervascular . \n the tumor was doubled with the sympathetic chain and therefore , the proximal and distal chains of tumor were divided with clips . \n there were no complications and only minimal hypesthesia at the right t2 dermatome ( fig . \n there have been several efforts to treat thoracic dumbbell tumors . in general , a single stage posterior approach including partial laminectomy and unilateral facetectomy has been performed1,11 ) . \n however , more invasive procedures are required for tumors with large intra - thoracic components , including wide incision and resection of adjacent structures ( rib , transverse process and pedicle ) . for stabilizing the spine , spinal reconstruction with fusion instrument should be used1 ) . \n based on eden classification , dumbbell tumors are classified into 4 types , as follows : type 1 is intradural and extradural ; type 2 is intradural , extradural , foraminal , and paravertebral ; type 3 is extradural , foraminal , and paravertebral ; and type 4 is foraminal and paravertebral6 ) . \n first , partial laminectomy is performed to remove the intraspinal component of dumbbell tumors , after which open thoracotomy is conducted to remove the intrathoracic component . \n however , open thoracotomy requires division of one or more major muscles of the chest wall , including the latissimus dorsi , pectoralis , or serratus muscles with spreading of the ribs . \n currently , vats is applied widely in various thoracic surgeries including resection of lung or mediastinal masses . \n thoracoscopic incision is less invasive , sparing division of major muscles , which results in less postoperative pain , early recovery and lower morbidity3,4 ) . due to the feasibility of vats , combined laminectomy and vats \n however , the combined approach for thoracic dumbbell tumor has only been reported in case reports or technical notes due to rarity of thoracic dumbbell tumor . \n although our series only included seven cases , a combined approach using vats was applied in the largest number of patients . in our cases , \n considering the possible approach of vats to t1/2 , the combined approach could be applied for dumbbell tumors of all levels . \n however , sympathetic chain injury can occur during removal of upper thoracic tumors , and meticulous care is required . \n the best advantage of combined approach is early ambulation of patients due to less invasiveness . in our cases , all patients ambulated the day after operation , except for one with atelectasis . \n in addition , transfusion was not required because of lesser intraoperative bleeding below 400 ml . however \n , a combined approach may be difficult because intraoperative bleeding can obscure the operative field and vats enables only limited bleeding control in highly vascular tumors . in our case of hemangioma , \n therefore , we recommend that preoperative tumor embolization be considered in a combined approach for highly vascular dumbbell tumors . there is still debate regarding whether this combined approach is really less invasive . \n the operation time of the combined approach is 4 to 6 hours , which is similar to that of the single posterior approach with instrumentation . \n nevertheless , our opinion is that the combined approach is less invasive than a single posterior approach because it requires no spinal instrumentation , and results in less intraoperative bleeding , less postoperative pain , and early ambulation . \n therefore , a combined approach is a good alternative method for removal of thoracic dumbbell tumors . \n one - stage posterior minimal laminectomy and vats are a safe and less invasive technique for removal of thoracic dumbbell tumor without instrumentation and instability . \n this method can reduce intraoperative bleeding and postoperative pain , resulting in early ambulation and recovery . in highly vascular tumors ,", "role": "user" }, { "content": "objectivethis study was conducted to assess the surgical results of one - stage posterior minimal laminectomy and video - assisted thoracoscopic surgery ( vats ) for the treatment of thoracic dumbbell tumor and to describe its precise technique . \n in addition , we investigated the technique s usefulness and limitations.methodsseven cases of thoracic dumbbell tumor ( two men and five women , mean age , 43 years ) were analyzed retrospectively . \n pathological findings included schwannoma in four patients , neurofibroma in two patients , and hemangioma in one patient . \n the location of tumors varied from t2/3 to t12/l1 . \n dumbbell tumors were resected by one - stage operation using posterior laminectomy followed by vats without instrumentation . \n clinical data were reviewed.resultsthe mean follow - up period was 25 months ( range , 358 months ) , and the operative time ranged from 255 to 385 min ( mean , 331 min ) , with estimated blood loss ranging from 110 to 930 ml ( mean , 348 ml ) . \n the tumor was completely resected without instrumentation and postoperative instability in all cases . \n postoperative complications included atelectasis and facial anhydrosis in one case each.conclusionone-stage posterior minimal laminectomy and vats may be a safe and less invasive technique for removal of thoracic dumbbell tumor without instability . \n this method has the advantage of early ambulation and rapid recovery because it reduces blood loss and postoperative pain .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: lithium borohydride is an ionic compound consisting of li cations and [ bh4 ] anions , which is \n of interest for energy storage and conversion . \n it contains 18.5 wt % hydrogen and thus is a promising \n material for solid - state hydrogen storage . \n however , the hydrogen is released above 673 k in multiple steps , \n whereas low hydrogen desorption temperatures and fast kinetics are \n required for integration with low - temperature fuel cells . at room \n temperature \n this low - temperature phase transforms to a hexagonal phase at about \n 383 k. interestingly , li ions in the hexagonal ( high temperature ) \n phase of libh4 are highly mobile , resulting in an ionic \n conductivity of 10 s / cm at 390 k ; therefore , this \n material is also considered to be promising as a solid - state ionic \n conductor for li ion batteries \n . however , \n for battery applications , high ionic conductivity at room temperature \n is required , and it has recently been shown that this might be achieved \n by partial anion substitution or nanoconfinement . \n it is well known that nanosized materials have physical and chemical \n properties different from those of the corresponding macrocrystalline \n materials . \n the special properties of nanomaterials originate from \n their high surface to volume ratio . for \n metal hydrides , \n the effects of nanosizing include a reduction of hydrogen \n diffusion distances and increased specific surface area so that the \n rate of hydrogen exchange is increased . to sustain the properties \n of nanoparticles \n , their growth under operating condition must be avoided , \n for instance , by confining the hydride nanoparticles in porous materials . \n these are usually carbon materials because of their chemical inertness \n and high - temperature stability . \n carbon materials are also known to \n have a high thermal conductivity , which is beneficial for heat management \n during hydrogen cycling . on the other hand , \n oxidic porous materials \n such as silica are promising for confining libh4 for solid - state \n battery electrolytes , as low electronic conductivity is a prerequisite \n for electrolytes in all solid - state batteries . \n for libh4 , nanoconfinement improves the hydrogen \n sorption \n kinetics as well as reversibility . \n reported that nanoconfined libh4 exhibits low activation \n energy for hydrogen desorption . upon cycling , the confined phase has \n a higher hydrogen cycling efficiency than does nonconfined libh4 . a study by cahen \n et al . , \n using sba-15 templated ordered \n porous carbon materials as scaffolds , shows that nanoconfined libh4 starts to release hydrogen at 473 k and desorbs about 3 wt \n % hydrogen within 1.5 h at 573 k , which is only 0.5 wt % for macrocrystalline \n libh4 . \n another important effect of nanoconfinement \n on libh4 is the increased [ bh4 ] and li mobility . \n ionic conduction \n reaches \n 0.1 ms / cm at room temperature for libh4 confined in silica \n materials , more than 3 orders of magnitude higher than for macrocrystalline \n libh4 . \n nuclear magnetic resonance \n ( nmr ) measurements on carbon - confined libh4 by shane et \n al . showed fast hydrogen mobility for \n the confined libh4 . \n however , the nmr signal also showed \n two distinct fractions of libh4 : one with a significantly \n higher mobility and another with mobility close to that of bulk libh4 . \n quasielastic neutron scattering ( qens ) confirmed that libh4 confined in carbon scaffolds comprises highly mobile [ bh4 ] units . \n it was proposed that this could \n be related to the strain developed during the confinement procedure . a detailed qens study by verdal et al . \n identified the nature of the motion of the [ bh4 ] units and showed two fractions of libh4 with different mobilities . \n the mobile fraction increased \n with decreasing pore size , leading to the proposal of a core \n shell \n model with a mobile shell thickness of about 0.80.9 nm at \n 360 k. using differential scanning calorimetric ( dsc ) studies , liu \n et al . showed that confinement in carbon pores lowers the solid \n was , as far as we \n are aware , the first to study libh4 confined in mesoporous \n silica instead of carbon . \n it showed two distinctly different phases ; \n a phase with high li and hydrogen mobility and another \n with li and hydrogen mobility that resembles that of macrocrystalline \n libh4 . \n herein , we use ordered mesoporous silica and \n carbon scaffolds to \n systematically study the impact of pore size , pore geometry , and the \n chemical nature of scaffolds on confinement effects for nanoconfined \n libh4 . by combining hydrogen dynamics studies with calorimetric \n analysis \n , we obtain quantitative information on the two different \n fractions of libh4 that exist in the nanocomposites . \n this \n study reveals that both the pore size and the nature of the scaffold \n have a significant influence on the confinement effects . \n the effects \n are more pronounced for sio2 than for carbon materials \n with similar pore sizes and pore geometry . \n ordered mesoporous silica , sba-15 , with a 1d pore system was synthesized \n according to the procedure described by zhao et al . using block copolymer pluronic p123 as a template and tetraethylorthosilicate \n as the silica source . \n different pore sizes were obtained by changing \n the aging time and temperature during the hydrothermal treatment ( overview \n in table 1 ) . \n the porous \n carbon materials were carbon aerogels that were synthesized through \n resorcinol - formaldehyde condensation catalyzed by sodium carbonate \n as described by pekala et al . \n the pore \n size was tuned by changing the organic to water ratio during the gel \n synthesis . \n total pore volume measured at p / p0 = 0.95 for silica scaffolds \n and at p / p0 = 0.99 for \n carbon scaffolds . \n microporous \n volume determined from \n the t - plot amount of libh4 outside \n the pores as measured by dsc and expressed as the weight percentage \n of the nanocomposites . before \n melt infiltration with libh4 , support porosity \n was measured with nitrogen physisorption performed at 77 k using a \n micromeritics tristar 3000 . \n the total pore volume was derived from \n the absorption branch of the nitrogen isotherms at p / p0 = 0.95 . \n the pore size distributions \n of the sio2 were calculated from the adsorption branch \n of the isotherm by the nl - dft method using the cylindrical pore kernel . \n the values are derived from the peak of the pore size distribution . \n typically for pore sizes < 7 nm , the nl - dft values are more accurate , \n and about 1 nm larger , than those obtained via the bjh analysis . \n the pore size distributions of carbon samples \n were calculated from the desorption branch using the bjh method with \n the carbon black stsa equation . \n melt infiltration was employed to \n confine libh4 in the porous scaffolds with loadings corresponding \n to full pore filling . \n the sio2 scaffolds were dried prior to sample synthesis under an ar \n flow at 473 k for at least 24 h to remove possible residual water . \n the carbon scaffolds were dried in a hydrogen flow at 873 k for 5 \n h to remove oxygen - containing groups and to subsequently passivate \n the resulting dangling bonds with hydrogen as well as to gasify the \n most reactive fraction of the carbon material . \n the preparation of nanocomposites requires good contact \n between \n libh4 and the scaffolds , and this was achieved by thoroughly \n mixing them at least for 10 min . \n after that , the physical mixture \n was transferred into a graphite sample holder placed in a stainless \n steel autoclave and initially pressurized to 50 bar of h2 . \n the mixture was heated at 5 \n k / min to 573 k , which is slightly above the libh4 melting \n temperature , and remained at that temperature for 25 min to allow \n the melt infiltration of libh4 into the pores . \n x - ray \n diffraction patterns of the samples were recorded using a \n bruker d8 advance with co k radiation , = 1.78897 . \n the xrd samples were placed on an airtight sample holder to prevent \n sample oxidation . \n microstructural analysis was performed using an \n fei tecnai 20 transmission electron microscope ( tem ) with a field - emission \n gun operated at 200 kv . \n the samples were deposited onto carbon holey \n copper grids ( 200 mesh ) by dipping the grid in a ground powder . typically , \n during the insertion of the sample holder into the microscope column , \n the sample was exposed to air for about 25 s. differential scanning \n calorimetric ( dsc ) measurements were performed \n with a high - pressure dsc from mettler toledo ( hp - dsc1 ) . \n the temperature \n and the heat flow were calibrated using certified gallium , indium , \n and zinc references . \n the nanocomposites ( 1020 mg ) were placed \n in a 40 l hermetically sealed aluminum pan . \n the data were recorded \n while heating and cooling between 305 and 565 k at 5 k / min and 20 \n bar of h2 . \n each measurement involved two to three cycles \n to check the sample stability and to verify the reproducibility . \n the \n thermograms were processed with stare software to determine the transition \n temperatures and the enthalpies . \n the transition temperature is the \n extrapolated onset temperature , an intersection of the tangential \n line drawn through the point of maximum slope and the baseline . \n the \n enthalpy is determined from the integration of the phase - transition \n peak . \n the enthalpy data of the nanocomposites were compared to those \n of the macrocrystalline libh4 measured under the same conditions . \n the error in the measured temperature is less than 1 , and that \n of the measured enthalpy is in the range of 68% . to determine the confined fraction of libh4 , the amount of crystalline , extraporous libh4 was \n measured by comparing the experimental enthalpy of the solid \n solid \n phase transition at the bulk transition temperature for the nanocomposites \n with that of macrocrystalline libh4 measured under the \n same conditions . \n the amount of the confined phase is the total amount \n of libh4 in the sample minus the amount of crystalline \n and hence extraporous libh4 . \n when the extraporous libh4 peak was not observed , all of the libh4 was assumed \n to be confined . \n quasielastic \n neutron scattering ( qens ) measurements were carried out using time - of - flight \n ( tof ) neutron spectrometer focus located at continuous spallation \n source sinq at the paul scherrer institute , switzerland . \n isotopically enriched b ( 99.5% ) samples ( chemical purity \n 98% ) , purchased from katchem , were used to avoid the strong neutron \n absorption by b , present in natural boron . the samples \n were loaded in lead - sealed , double - walled , hollow cylindrical containers . \n the diameter of the cylindrical container was 10 mm , and the wall \n distance ( i.e. , the sample space ) was 1 mm . \n incident neutrons were \n prepared with a wavelength of i = 4 , corresponding \n to an incident energy of ei = 5.11 mev \n and an incident velocity of vi = 989 m / s . \n the scattering intensity i(2 , t ) is recorded as a function of scattering angle 2 and time \n of flight t. data reduction is carried out using \n data analysis and visualization environment dave to convert the instrument - specific i(2 , t ) to the scattering function s(q , ) . \n thereby , the scattering intensity is expressed \n as a function of the momentum transfer q = \n ki kf , where ki and kf are the incident and scattering wave vectors , and as \n a function of the energy transfer = ei ef , where ei and ef are the \n incident and scattering neutron energies , respectively . \n because of \n the large incoherent scattering cross section inc of hydrogen as compared to those of lithium , carbon , and boron , \n we attribute all scattering intensity to the incoherent scattering \n of hydrogen . \n hence , the contributions of other species , coherent scattering , \n and multiphonon events are neglected . in bulk \n libh4 , rapid \n reorientations of the [ bh4 ] anions are \n responsible for the quasi - elastic signal . at the instrumental settings \n used , \n the energy resolution defining the width of the elastic line \n equals e= 0.2 mev . \n data acquisition and treatment \n were carried out as described earlier , and the spectra \n were binned in a range of q values of 0.5 < q < 2.5 . \n the resulting qens spectra were analyzed using general purpose \n curve - fitting utility pan , following the procedure described in the \n previous publication . \n table 1 gives an \n overview of the textural \n properties of the supports as well as the properties of the nanocomposites , \n including the loading and the amount of confined libh4 in \n each sample , i.e. , the fraction of pores that was filled . \n we tuned \n the pore radii from 3.3 to 6.1 nm and from 3.1 to 20 nm for the silica \n and carbon materials , respectively . \n the ordered mesoporous silica \n sba-15 materials comprise uniform parallel pores connected by intrawall \n porosity . \n the porosity of the carbon materials originates from interparticle \n space and is dominated by carbon particles of 510 nm in size , as confirmed by the transmission electron micrographs \n of these supports ( figure s1 ) . \n the pore \n volumes of the supports are between 0.3 and 0.8 cm / g for \n silica materials and between 0.53 and 1.37 cm / g for the \n carbon scaffolds , and this enables us to make samples with confined \n libh4 loading ranging from 13.2 to 36 wt % with 60100% \n pore volumes filled with libh4 . \n the high carbon pore filling \n ( > 70% ) is achieved by the proper mixing of libh4 and \n the \n scaffolds and by multiple melt infiltration ( at least two sessions \n of melting and cooling under hydrogen pressure ) . \n neutron \n scattering is a powerful tool to study the dynamics of \n complex hydrides because of the incoherent neutron scattering cross - section \n of hydrogen . \n therefore , the effects of pore size and the nature of \n the scaffold on the hydrogen dynamics of our nanoconfined libh4 were investigated using qens . \n qens probes the transfer of \n small amounts of energy compared to the neutron incident energy . \n these \n small energy transfers are caused by energy redistributions in the \n samples originating from atomic translations or rotations . \n the qens \n spectra of the macrocrystalline ( bulk ) libh4 recorded between \n 300 and 500 k ( figure 1a ) show that the patterns changed significantly \n above 380 k. this is a clear indication of the structural phase transition \n of libh4 at this temperature . \n the low - temperature phase \n is characterized by a broad inelastic feature with distinct structure \n at around 1.5 ms . \n the elastic line is clearly separated from the inelastic \n part of the spectrum by an intensity minimum , indicative of a low \n density of states at low energy transfers . above the phase - transition \n temperature , \n the separation between the elastic and inelastic parts \n of the spectrum disappears and the inelastic part of the spectrum \n shows no distinct features . in the ht phase , the quasielastic component , \n seen as a broad background around the elastic line , broadens , and \n the intensity at the base of the elastic line drops with increasing \n temperature ( with the arrow in figure 1 pointing to this feature ) . \n time - of - flight \n spectra for bulk libh4 ( a ) and libh4 confined \n in carbon ( b ) and sio2 ( c ) with pore \n radii of 5.6 and 5.9 nm , respectively . \n figure 1b , c \n shows \n the time - of - flight patterns for libh4 confined in carbon \n and silica ( sba-15 ) scaffolds with pore radii of 5.6 and 5.9 nm , respectively . \n compared to macrocrystalline libh4 , the broadening of the \n base of the elastic line is less pronounced . also , the sudden shift \n of the spectra with temperature , representative of the structural \n phase transition , is less apparent for the nanoconfined libh4 , in line with previous results based on nmr . \n these results are also in line with previous qens measurements that \n showed that the structural phase transition of libh4 was \n significantly suppressed when the compound was confined in high - surface - area \n nanoporous graphite ( hsag ) with an average pore size of between 2 \n and 3 nm . even though , comparing \n the silica and carbon materials , the spectra \n look rather similar at first glance , small but distinct differences \n are present . in the case of the silica ( figure 1c ) , \n all high - temperature spectra coincide \n at the base of the elastic line . in contrast , for the carbon case \n ( figure 1b ) there is \n a clear temperature dependence of the quasielastic broadening , although \n it is less pronounced than for macrocrystalline libh4 ( figure 1a ) . \n therefore , libh4 confined in carbon displays intermediate behavior between \n macrocrystalline libh4 and libh4 confined in \n sio2 . because the materials have very similar pore sizes , \n we can conclude from these observations that silica materials exert \n stronger confinement effects on libh4 than do carbon scaffolds . \n c \n shows the time - of - flight spectra of a series of libh4/sio2 nanocomposites with different pore sizes \n . a close look at \n the spectra reveals that at high temperatures the signature of macrocrystalline \n libh4 is less pronounced for the smaller pore radii . \n the \n temperature at which the signature of the structural phase transition \n disappears decreases with decreasing sio2 pore size : the \n tof spectrum of sio2 - 5.9 shows the signature of the high - temperature \n phase at 380 k , whereas for sio2 - 4.4 and sio2 - 3.6 , the highest temperatures at which it is observed are \n 350 and 333 k , respectively . \n this means that the temperature at which \n the structural transition for nanoconfined libh4 occurs \n decreases with decreasing pore radius . \n hence , the hydrogen dynamics \n of nanoconfined libh4 are also influenced by the pore size \n of the silica scaffold material . \n tof spectra for libh4 confined \n in sio2 with \n pore radii of ( a ) 5.9 , ( b ) 4.4 , and ( c ) 3.6 nm . \n the qens results suggest the presence of at least two distinct \n fractions of libh4 in the silica scaffold ; however , the \n present data do not allow us to unambiguously deconvolute the measured \n qens spectra into two lorentzian contributions . \n hence , we modeled \n the spectra using an elastic peak of width el and \n an integrated area iel and a single lorentzian \n curve with a width qe and an integrated area iqe for the quasi - elastic broadening . \n the width \n el of the elastic line was fixed to the width of \n the measured elastic line of a vanadium standard sample , corresponding \n to the instrumental resolution . in macrocrystalline libh4 , \n the phase transition is evidenced \n by a sudden change in the quasielastic broadening and a distinct change \n in activation energy between 360 and 390 k. all quasi - elastic broadenings \n measured on the confined samples lie in between the data for macrocrystalline \n libh4 . with decreasing pore \n the deviation from the bulk behavior \n is larger for the carbon in the ht phase , whereas for the sio2 it is larger in the lt phase . in other words , \n compared to \n carbon , sio2 more strongly favors disordered , mobile , high - temperature - like \n behavior at room temperature . at low temperature , qe increases with decreasing pore \n the hydrogen mobility at low temperatures in the \n confined samples is much higher than for macrocrystalline libh4 , and the smaller the pore sizes , the stronger the deviation \n from the bulk value . \n temperature dependence \n of the quasielastic broadening for macrocrystalline \n libh4 and libh4 confined in sio2 and \n carbon with different pore sizes . \n the hydrogen mobility as measured by quasi - elastic \n neutron scattering shows clear differences between libh4 nanoconfined in sio2 and in c matrices , indicating that \n the confinement effects are influenced by the chemical nature of the \n scaffold . \n a quantifiable aspect of confinement is the change in the \n thermodynamic stability and hence the phase - transition temperatures \n and enthalpies . \n because the libh4 phase transitions involve \n a significant amount of enthalpy , calorimetry is a powerful option \n for investigating the phase - transition processes . \n figure 4 illustrates dsc measurements \n of macrocrystalline libh4 and libh4 confined \n in 3.1 nm pores of a carbon matrix . during heating , \n the low - temperature \n solid phase transforms into a high - temperature phase with an onset \n temperature of 386 k for the macrocrystalline libh4 . \n further \n heating leads to the melting at 558 k. during cooling , liquid libh4 starts to solidify at a slightly lower temperature than for \n melting . \n dsc thermograms of bulk libh4 ( above ) and the nanoconfined \n libh4 sample ( libh4/c-3.1 ) ( below ) . for the confined libh4 \n , the dsc shows \n two additional \n peaks ; one below the solid solid phase transition and the other \n below the melting temperature . \n if all libh4 is confined \n in the pores , then only the depressed peaks belonging to the confined \n phase were observed , as shown for some of the nanoconfined samples \n ( e.g. , samples sio2 - 4.4 and c-3.8 ) in figures \n the peaks of the confined phase are broadened , and the intensity \n of the peaks corresponding to features of the bulk is reduced . \n another \n important point we found with dsc is that the phase transitions are \n fully reversible under hydrogen pressure ; we found no indication of \n side reactions with either the carbon or the silica scaffolds . \n table 2 gives an overview \n of the calorimetric results for libh4 confined in silica \n and carbon materials with different pore sizes . \n the table lists the \n onset temperatures , the depression in the phase transition , and the \n enthalpies of the solid solid phase transition and melting . \n the onset temperatures and the enthalpies depend on the pore radius . \n the melting temperature is shifted more than 100 down for libh4 confined in 3.3 nm sio2 pores . melting - phase transition \n of nanoconfined libh4 . \n ( a ) \n dsc thermograms of libh4/sio2 ( upper panel ) \n and libh4/c ( lower panel ) . \n the bulk melts at 559 k and freezes at 558 k. the enthalpies \n were calibrated using \n macrocrystalline ( mc ) libh4 as a reference . \n the raw data measured values were 2.26 and 4.60 kj / mol for the solid \n solid \n transition and melting , respectively solid solid phase - transition temperatures of confined libh4 : ( a ) dsc thermograms of libh4/sio2 during \n heating ( upper ) and libh4/c ( lower ) . \n ( b ) onset of the phase - transition \n temperature as a function of inverse pore radius ( right ) . \n the dsc thermograms of \n melting behavior of libh4/sio2 and libh4/c are shown in figure 5a . \n the size dependence of the melting temperatures \n was analyzed by plotting t as a function of \n 1/r , as shown in figure 5b . \n it can be seen that the melting - point \n depression is inversely proportional to the pore radius of both the \n sio2 and c scaffolds . \n it is generally accepted that \n a shift in melting temperature is \n related to size and interface effects , and it is typically ascribed \n to the increasing contribution of interfacial energy with decreasing \n size . \n the relationship between the depressed melting temperature \n and the particle radius is often described by the gibbs \n thomson \n relation , i.e. , eq 1 , \n where the ratio between the depressed temperature ( t ) and the temperature of the bulk libh4 ( t0 ) scales with the interface energy ( ) \n and inverse pore radius ( rp).1 in eq 1 , the enthalpy of the phase transition , h , is assumed to be independent of the particle size . \n this \n simplified \n description also assumes that the molar volume , vm , is the same for both phases involved in the transition . \n in some cases \n , the application of the gibbs thomson relation \n requires a correction for an interfacial layer thickness , t , a fraction of the material that does not participate \n in the phase transition . \n for example , for ice melting in nanopores \n the layer thickness is on the order of 0.4 nm . to estimate interface energies from our experimental data , \n the observed temperature depressions were fitted using eq 1 . assuming no inert interfacial \n layer ( t = 0 ) , the resulting interface energy is \n 0.018 j / m . if including an inert layer , the surface energy \n is 0.015 j / m and t is 0.6 nm . \n this gives \n a first indication of the interfacial energy , but we show in the next \n section how the interfacial energy can be determined more accurately . \n it is interesting to observe that the calculated effective interfacial \n energy for the confined samples is about an order of magnitude lower \n than the surface energy of macrocrystalline libh4 , 0.12 \n this points to a strong favorable interaction \n between the silica pore walls and the nanoconfined libh4 , resulting in a much lower effective interfacial energy and hence \n a high stability of the confined libh4 . \n the impact \n of the size on the solid solid phase - transition \n temperatures has never been investigated in detail , especially for \n silica scaffolds ; hence , we did a detailed study on these effects \n for the carbon and silica materials . for libh4 confined \n in silica , \n the depression is largest for the smallest pore radius \n and up to 49 for sio2 with 3.3 nm pores ( figure 6a , upper frame ) . \n as can be seen in figure 6a ( lower frame ) , for carbon scaffolds the impact of pore size \n on the solid solid depression is much smaller than for the \n silica scaffolds . \n for example , the depression was 49 k for sio2 - 3.3 and only 27 k for c-3.1 even though they have similar \n pore radii . \n the differences are clearly seen in figure 6b in which the phase - transition temperature \n shifts are plotted as a function of 1/r . in all cases , \n the measured enthalpy of the solid solid phase \n transition of the confined phase ( table 2 ) decreases with decreasing pore size of \n the scaffold . decreasing transition enthalpies of confined phases \n have also been observed for water , organic \n materials , and metals.figure 7a shows the measured enthalpies normalized to that of the macrocrystalline \n libh4 . \n , namely , that \n the measured enthalpy is due to material in the core of the pores \n that undergoes a phase transition ( and hence material close to the \n pore wall does not contribute ) and cylindrical pore geometries , then \n the relative enthalpy dependence on the pore radius ( rp ) can be expressed by eq 2 , where t is the interfacial thickness.2fitting \n the data using eq 2 results \n in an interfacial \n layer thicknesses of 1.41 0.16 and 1.94 0.13 nm for \n the carbon and silica scaffolds , respectively . for carbon - confined \n libh4 , \n the value is larger than the 0.830.99 nm \n at 373 k estimated by shane et al . \n the \n thicker interfacial layer for libh4/sio2 indicates \n that the specific interaction of libh4 with sio2 extends over longer distances than for c. it is important to mention \n here that pore walls are not atomically flat . \n for instance , it is \n known from the work of gommes et al . that the amplitude of surface \n corrugation of the silica ( sba 15 ) is 1.6 nm , which is close to the value of 1.94 nm observed for the libh4 interfacial layer . \n however , the specific surface area of \n carbon materials and hence the effective pore corrugation are even \n larger than those for silica with a similar pore size ( table 1 ) . \n this strengthens the conclusion \n that the confinement effects inherently extend over longer distances \n in the case of silica than for carbon , as the difference in interfacial \n layer thickness can not be attributed to pore corrugation effects . \n size - dependence \n enthalpy and depression for the structural phase \n transition of nanoconfined libh4 . \n ( b ) depression of the solid solid phase - transition \n temperatures and the fitted curves of the gibbs \n thomson relation \n ( eq 1 ) . using those interfacial layer thicknesses determined \n from the above \n analysis , the effective interfacial energy differences for the two \n structural phases of libh4 confined in either sio2 or c can accurately be determined and are summarized in table 3 . \n the interfacial \n energy difference for the sio2/libh4 interface \n ( 0.053 j / m ) is higher than for the c / libh4 interface \n ( 0.033 j / m ) . \n this is most likely due to the different \n interaction between libh4 and the pore walls of the scaffold \n materials . \n the surface of silica is polar with a surface energy of \n about 0.260 j / m , whereas the carbon \n surface is apolar with a low surface energy of 0.032 j / m , and hence a stronger interaction with silica \n than with carbon might be expected . the indicated error \n is the fitting \n error ; the error in the dsc measurements is about 69% . \n carbon aerogels have a broader pore \n size distribution than the ordered mesoporous silica ( sba-15 ) . \n we \n therefore additionally measured the calorimetric properties of libh4 confined in ordered nanoporous carbon scaffolds possessing \n relatively narrow pore size distributions ( figure s3 ) to investigate whether the carbon pore structure and pore - size \n distributions have a large influence on the confinement effects . \n figure 8 shows the dsc thermograms \n of nanocomposites prepared with microporous carbon ( 0.8 nm \n pore radius ) , cmk-3 ( 1.8 nm pore \n radius ) , and kroll carbons ( ca . \n the thermograms \n of nanocomposites prepared with carbon aerogel and sio2 ( 4.8 and 6.1 nm pore radiui , respectively ) are also included . \n interestingly , \n only the peak corresponding to the structural phase transition for \n the unconfined ( macrocrystalline ) libh4 is observed in \n sample cm-0.8 ( prepared with microporous carbon ) . note \n that about 82% of the libh4 in this sample is confined \n ( table 4 ) . \n we attribute \n the absence of the structural phase transition for the confined fraction \n to the fact that the pore radius is below the interfacial layer thickness \n ( 1.41 0.16 nm ) determined for libh4 nanoconfined \n in carbon materials . \n therefore , libh4 confined in carbon \n pores below this range is not expected to show any phase transition . \n dsc thermograms \n for the solid solid phase transition of \n libh4 confined in ordered nanoporous carbon ( cm ) with a pore radius as indicated ( in nm ) on the figure . \n thermograms \n of a nanocomposite prepared with carbon aerogel ( ca ) and \n sba-15 ( sio2 ) are also added for comparison . \n the asterisk \n ( * ) indicates the onset temperature of the phase transition for the \n nanoconfined fractions . \n the onset temperatures for the structural phase transition \n for \n the confined fraction of libh4 in cm-1.8 and \n cm-4.9 are 301 and 292 k , respectively , compared to about \n 378 k for macrocrystalline libh4 . \n the slightly lower onset \n phase - transition temperature for cm-4.9 is due to the presence \n of carbon with pores of less than 1.8 nm in radius . \n this also explains \n why the phase transition extends over a longer temperature range than \n that of cm-1.8 . \n however , the peak of the phase transition \n is clearly at a much higher temperature for cm-4.9 than \n for cm-1.8 . \n these observations indicate that the pore size \n distributions of the scaffold are reflected in the peak width ( broadness \n of the phase - transition event ) whereas the average pore size of the \n scaffold determines the peak temperature of the phase transition . \n a clear proof of this is the fact that the dsc profile of cm-4.9 is similar to that of the nanocomposite prepared with carbon \n aerogel with a similar average pore size ( ca-4.8 ) and pore - size \n distributions but is much sharper because of the slight differences \n in pore size distributions ( figure s3 ) . \n on the other hand , \n the peak temperatures for cm-4.9 and \n ca-4.8 are at even a slightly higher temperature than for \n sio2 - 6.1 despite the fact that this silica has larger pores . \n these results confirm that the confinement effects are indeed more \n pronounced for sio2 than for carbon . \n another clear evidence \n comes from the fact that the nanocomposites prepared with the ordered \n mesoporous carbon materials have interfacial layer thicknesses ( table 4 ) that are very close \n to the average value determined for the samples prepared with carbon \n aerogel ( table 1 ) . \n the interfacial layer thickness for these samples is estimated from eq 2 . \n the observed difference \n in the nanoconfinement effects is mainly due to the differences in \n the surface chemistry of the nanoscaffolds . \n geometric differences \n might also play a role ; sba-15 has a more defined pore geometry ( hexagonally \n packed cylindrical pores ) than the ordered nanoporous carbon . \n quasielastic neutron scattering shows a \n clear impact of confinement \n on the hydrogen mobility , with the behavior of libh4 in \n carbon scaffolds being closer to that of macrocrystalline libh4 than when confining libh4 in silica scaffolds . \n the temperature of the solid solid phase transition of libh4 is also depressed more strongly for silica than for carbon \n scaffolds and shifts from 387 to 338 k for libh4 confined \n in 3.3 nm silica pores . \n pore - size - dependent enthalpy measurements \n confirm that there is a significant fraction of libh4 near \n the pore walls that does not undergo a structural phase transition , \n and assuming that this is a well - defined interfacial layer , we quantify \n its thickness as 1.94 0.13 nm for sio2 and 1.41 \n 0.16 nm for carbon scaffolds . if interpreting the shift of \n the phase transition in terms of the interfacial energy difference , \n the difference between the orthorhombic- and hexagonal - phase libh4-sio2 interfaces is 0.053 j / m , whereas \n for the libh4carbon interfaces this is only 0.033 \n j / m . hence , we show a size dependence of the hydrogen \n dynamics and confinement energetics of libh4 on pore size \n as well as on the chemical nature of the scaffolds . \n this suggests \n that the nature of the scaffold and surface modification are important \n tools for tuning the hydrogen sorption and ion conduction properties \n of confined complex hydrides .", "role": "user" }, { "content": "libh4 is \n a promising material for hydrogen storage and \n as a solid - state electrolyte for li ion batteries . \n confining libh4 in porous scaffolds improves its hydrogen desorption kinetics , \n reversibility , and li+ conductivity , but little is known \n about the influence of the chemical nature of the scaffold . here \n , \n quasielastic neutron scattering and calorimetric measurements were \n used to study support effects for libh4 confined in nanoporous \n silica and carbon scaffolds . \n pore radii were varied from 8 \n to 20 nm , with increasing confinement effects observed with decreasing \n pore size . for similar pore sizes , \n the confinement effects were more \n pronounced for silica than for carbon scaffolds . \n the shift in the \n solid solid phase transition temperature is much larger in \n silica than in carbon scaffolds with similar pore sizes . \n a libh4 layer near the pore walls shows profoundly different phase \n behavior than crystalline libh4 . \n this layer thickness was \n 1.94 0.13 nm for the silica and 1.41 0.16 nm for the \n carbon scaffolds . \n quasi - elastic neutron scattering confirmed that \n the fraction of libh4 with high hydrogen mobility is larger \n for the silica than for the carbon nanoscaffold . \n these results clearly \n show that in addition to the pore size the chemical nature of the \n scaffold also plays a significant role in determining the hydrogen \n mobility and interfacial layer thickness in nanoconfined metal hydrides .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: congenital infiltrating facial lipomatosis ( cil - f ) of the face is a subgroup of lipomatous tumours . \n it is characterized by diffuse infiltration of mature adipose cells over facial soft tissue , rapid growth , and osseous deformity . \n they may occur anywhere in the body , being rare in the head and neck . \n the incidence of congenital infiltrating lipomatosis on the face is rare , and only a few cases have been reported . \n it was first described as a distinct clinicopathological entity by slavin et al . in 1983 in a patient with a unilateral swelling over the parotid region . \n all reported cases had uncertain prognosis with high rates of recurrence and variable postoperative cosmetic improvement . due to its diffuse infiltration and involvement of important facial structures , \n a 17-year - old female patient presented with the chief complaint of swelling over the left side of the face since birth . \n no defects associated with vision , respiration , swallowing or other movements were reported by the patient . \n the patient had undergone surgical interventions for the swelling on two previous occasions , at the age of 13 and 15 years respectively . \n diffuse swelling was present on the left side of the face , extending superiorly from the infraorbital area up to the lower border of the mandible , inferiorly , and medially from the midline of the face up to the preauricular area laterally . \n the borders were ill - defined , with a scarred surface due to previous surgeries [ figure 1a ] . \n on palpation the swelling was soft in consistency , nontender , nonpulsatile , and non - compressive . \n a nevus measuring about 7 cm in size with irregular borders was noticed along the midline of the skin over the neck [ figure 1b ] . \n unilateral macroglossia and enlarged ipsilateral hypertrophy of the maxillary and mandibular alveolar process [ figure 1c ] were observed . \n a previous surgical scar with an infraorbital nevus extending up to the hairline was also present [ figure 2d ] . \n a computed tomography ( ct ) scan revealed hypertrophy of the left cranial vault , in the left frontal and parietal region , and a zygomatic complex with ipsilateral enlargement of the maxillary sinus and soft tissue hypertrophy on the left lower third of the face was also observed [ figure 3e ] . \n the axial section also revealed hypertrophy of the medial pterygoid and masseter on the left side [ figure 3f ] . \n three - dimensional reconstruction tomography revealed left condylar hypertrophy [ figure 4 g and 4h ] . \n an incisional biopsy from the buccal mucosa , through the intraoral approach , revealed mature adipocytes , sparse myxoid areas , and inflammatory cells [ figure 5i ] . due to the recurrent nature of the swelling , \n clinical photographs nevus , hyperplasia , and macroglossia previous surgical scars and infraorbital nevus extending to the hairline ct scan reveals hypertrophy of the left cranial vault in the a b left frontal and parietal region , and zygomatic complex with ipsilateral enlargement of the maxillary sinus and soft tissue hypertrophy three - dimensional reconstruction tomography reveals left condylar hypertrophy histopathology report reveals mature adipocytes , sparse myxoid areas , and inflammatory cells - h and e , 1000 \n congenital infiltrating facial lipomatosis ( cil - f ) of the face is a subgroup of lipomatous tumours and diffuse neoplastic or non - neoplastic proliferation of the mature fat cells . \n it is characterized by diffuse infiltration of mature adipose tissue over the normal muscle fibers and a rapid growth rate with associated osseous hyperplasia . \n the term , congenital infiltrating lipomatosis of the face , was first used in 1983 , when slavin et al . \n , reported three cases of congenital proliferating and infiltrating lesions of the adipose tissue involving the face . \n they described the following characteristic histomorphological findings : infiltration of fat into the adjacent soft tissue and hypertrophy of the underlying skeleton , absence of malignant characteristics , absence of lipoblasts , presence of fibrous elements , increased number of vessels with unifocally thickened muscular walls , and increased number of nerve bundles of variable size , with focal fibrosis . \n trauma , chronic irradiation , muscular metaplasia , degenerative processes with fatty transformation , multipotential cells of embryogenic origin under the influence of hormones , congenital cytomegalovirus infection , and alteration in chromosome 12 , have been proposed as possible mechanisms for the lipomatous change . \n unlike lipoma , cil - f is non - encapsulated ; it extensively involves the deep soft tissue , muscle , nerve , or synovium . \n enzinger and weiss classified lipomatosis into three different entities : symmetrical lipomatosis ( usually in the neck ) , pelvic lipomatosis , and diffuse lipomatosis of the limbs and trunks . \n slavin et al . described the following characteristic histomorphological findings , infiltration of fat into the adjacent soft tissues and hypertrophy of the underlying skeleton , absence of malignant characteristics , absence of lipoblasts , presence of fibrous element , increased number of vessels , with unifocally thickened muscular walls , and increased number of nerve bundles of variable size with focal fibrosis . \n infiltrating lipomatosis of the face has been found on the cheek , buccal sulcus , tongue , lips , floor of the mouth , mental area , and parotid gland . \n ct and magnetic resonance imaging ( mri ) remain the most helpful tools for preoperative radiographic evaluation . \n lipomatoses contain a large amount of fat , usually 75% of their volume , and resemble lipomas on both ct and mr imaging ; but their internal septa may be broader and more nodular than those seen in lipomas . \n it must be noted that an inaccurate preoperative impression may be made due to the rarity of the disease and the features of local facial swelling . \n the differential diagnosis of lipomatosis includes several other conditions like hemifacial hypertrophy , lymphangioma , and neurofibromatosis of von recklinghausen , with its typical caf au lait spots . \n a high rate of recurrence , 60% of the reported head and neck cases , is perhaps attributable to the difficulties in radical excision . \n kamal et al . have stated that no surgical procedure must be performed until the end of the facial growth period and mention that delaying definitive surgery has other advantages such as minimizing the chances of damage to the facial nerve , decreasing the total number of procedures , and having a mature contralateral cheek contour to match . in conclusion , \n complete excision is most likely to cause regrowth if done below the age of adolescence , due to the effect of growth hormones . \n restoration of full facial symmetry is unlikely and the patient should be informed about the high rate of recurrence and that surgery is accompanied with a high complication rate .", "role": "user" }, { "content": "congenital infiltrating lipomatosis of the face ( cil - f ) has been described as a disorder in which mature lipocytes invade adjacent tissues in the facial region . \n its etiology and pathogenesis is unknown . \n the tumor is congenital in origin and occurs in infancy or early childhood . \n it is unencapsulated and characterized by diffuse infiltration of mature adipose tissue over normal muscle fibers , rapid growth , associated osseous hyperplasia , and a high recurrence rate postsurgical intervention . \n due to its diffuse infiltration and involvement of important facial structures , complete surgical excision is often impossible . \n cil - f is rare and there are only a few cases reported in the available literature . \n we present the case of a 17-year - old female , who reported with the complaint of recurrent unilateral facial swelling , with a history of two previous resections .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: urinary incontinence ( ui ) is defined by the international continence society as an \n involuntary loss of urine which is objectively a demonstrable , social , and hygienic \n problem1 . \n there are three main types of \n urinary incontinence : stress , urge , and mixed . \n stress urinary incontinence ( sui ) is the complaint of involuntary leakage on effort or \n exertion or on sneezing or coughing . during effort or exertion \n , the intra - abdominal pressure \n is raised , and the urethral sphincter is unable to maintain a pressure higher than that \n exerted on the bladder . \n subsequently , urine leakage occurs during everyday activities such \n as lifting , laughing , jumping , sneezing , or coughing2 , \n 3 . \n urge urinary incontinence ( uui ) is the complaint of involuntary leakage accompanied by or \n immediately preceded by urgency . during bladder filling , the bladder contracts abnormally , \n which creates a sensation of the need to urinate that becomes progressively stronger , is \n very difficult to ignore , and ultimately results in urine leakage . \n uui may be associated \n with overactive bladder syndrome ( oab ) , a condition that denotes urgency , frequency , and \n nocturia , with or without uui2 , 3 . \n finally , mixed urinary incontinence ( mui ) is the complaint of involuntary leakage \n associated with urgency and also with exertion , effort , sneezing , or coughing2 , 3 . \n ui is not only a serious medical condition in that it can lead to perineal rash , pressure \n ulcers , and urinary tract infections but also an undeniable social problem , creating \n embarrassment and negative self - perception . \n ui has been found to reduce both social \n interactions and physical activities4 and \n is associated with poor self - rated health5 , impaired emotional and psychological well - being , impaired sexual \n relationships , decreased quality of life6 , \n and depressive symptoms7 . \n women with ui \n are usually inactive and in the long term become isolated from community - based \n activities6 , 8 . \n there is also a risk of admission to a nursing house , specifically \n for older women with ui9 . \n ui affects approximately 20 million people in the united states , and the prevalence of ui \n in women ranges from 2646%10 . \n the \n economic costs of ui are substantial , comprising over $ 16 billion per year in the united \n states . \n reported that community - dwelling women spend nearly $ 750 per year out \n of pocket for incontinence management11 . \n physiotherapists have become involved in the clinical management of ui in women , as the \n presumptive underlying impairments ( i.e. , decreased pelvic floor muscle strength and/or \n endurance , decreased awareness of bladder irritants ) fall within the scope of physiotherapy \n practice according to the guide to physical therapist practice12 . \n consequently , there is a growing need to understand how \n physiotherapy interventions impact the ui symptoms , impairments , and functional limitations \n of women . \n this review article is designed to expose physiotherapists to a physiotherapy \n assessment of sui and the treatment and possibly preventive roles that they might play for \n women with sui . \n admission of an increased number of women with sui into physiotherapy clinics convinced us \n that control of this condition to some extent , at least from the mechanical point of view , \n is associated with physiotherapy interventions . \n reviewing a series of categories , including \n the anatomy of the pelvic floor and mechanism , pathophysiology , therapeutic modalities used \n in physiotherapy for sui , preventive role of pelvic floor muscle ( pfm ) training , and some \n barriers to successful physiotherapy outcomes , may help physiotherapists to obtain an \n insight into how sui may be controlled in a way to improve the quality of life of a sufferer \n of sui . \n although a number of physiotherapy treatments have been proposed for patients with \n sui , there are sufficient uncertainties and some controversies concerning the effectiveness \n of physiotherapy modalities , particularly due to the different treatment strategies . \n uncertainty and \n some possible barriers in performing physiotherapy treatments for sui \n patients prompted a narrative review , which might be of interest to physiotherapists \n managing sui patients . \n therefore , in the present review article , we reviewed the recent \n physiotherapy treatments for women with sui . \n specifically , our main goal was to review \n exercise therapy methods for strengthening the pelvic floor muscles that mainly control \n continence . \n a range of databases , including the cochrane library , medline , and cinahl was searched to \n identify articles addressing physiotherapy for sui . \n the search strategy involved entry of \n the word physiotherapy with a combination of other words such as physiotherapy , pelvic floor \n muscle , pelvic floor muscle training , pelvic floor muscle exercise , biofeedback , functional \n electrical stimulation , stress urinary incontinence , and women or female . \n this is a \n narrative review , and we were free to choose the related high - quality evidence based on our \n experience . \n so , we were confident that we would be able to find the main answers to our \n question . \n the pelvic floor \n is composed of striated muscles arranged in a dome - shaped sheet and is often described as \n a sling . \n these muscles are referred to as lying within either the deep or supercial \n pelvic floor . \n the fascia and muscles of the pelvic floor support the bladder , uterus , and \n rectum . \n muscles specic to the deep pelvic oor include the levator ani ( la ) and \n ischiococcygeus . \n the la is composed of three muscle bellies , including the iliococcygeus , \n pubococcygeus , and puborectalis . \n the iliococcygeal and pubococcygeal muscles form a \n horizontal shelf or hammock that spans from one pelvic sidewall to the other and then \n attaches laterally to the ischial spines and arcus tendineus fascia . \n the puborectalis \n muscle arises from the pubic bone on either side and extends into a sling or u - shape \n around the posterior rectum , which attaches to the walls of the vagina , urethra , and \n rectum13 , 14 ( fig . \n these include the \n anterior bers of the la , the transverses perinea supercialis and profundus , \n bulbospongiosus , external anal sphincters , and bers from urinary sphincters13 ( fig . \n 1 ) . \n the collective group of the la and coccygeus muscles with the surrounding \n fascia is referred to as the diaphragm of the pelvis . \n although it is poorly discussed , the \n pelvic oor has an important role in the function of core muscle stabilization . \n the core \n muscles are known as the muscles of the trunk ( abdominals , quadrates lumborum , spinal \n muscles including the multidus , and hip muscles ) , the diaphragm , and the pelvic oor . \n essentially , the pelvic oor is the oor of the core14 . \n the opening between the la through which the urethra , vagina , and rectum pass is the \n urogenital hiatus . \n the urogenital hiatus is anteriorly supported by the pubic bones and la \n and posteriorly by the perineal membrane and external anal sphincter . \n the perineal membrane is a dense triangular membrane located below the la with a central \n opening through which the vagina and urethra pass . \n the anatomy of the continence system can be organized into those structures that provide \n normal support to the lower urinary tract , and those that determine urethral closure \n force . \n the structures that provide normal support include the three layers of the pelvic \n floor structure . during bladder storage , activation of the sympathetic nervous \n system increases the tonic \n activity or contraction of the internal urethral sphincter to assist in preventing urine \n leakage . \n the lower urinary tract is innervated by three sets of peripheral nerves including ( i ) \n pelvic parasympathetic nerves ( s2-s4 segments ) that excite the bladder , ( ii ) lumbar \n sympathetic nerves that inhibit the bladder and excite the internal urethral sphincter , \n and ( iii ) pudendal nerves that excite the external urethral sphincter and pelvic floor \n muscles13 , 14 . \n the main anatomic hypotheses for development of sui are as follows : 1 ) the loss of \n structural support , 2 ) the hammock , and 3 ) the neural hypotheses3 . \n loss of structural support hypotheses : supportive structures to the \n bladder neck and urethra are necessary to maintain urethral closure pressure . \n intact \n attachments of the suburethral fascia to the fascia of the arcus tendineus and the la \n construct a firm shelf that remains stable when faced with increased forces generated by a \n cough or sneeze14 . \n disruption of this \n shelf , such as weakness of the la or damage to fascial attachments , as described in the \n loss of structural support hypotheses , could result in sui . \n the hammock hypotheses : in this hypothesis , the position of the urethra \n remains constant , but the compression of the pelvic floor muscles and fascia , which \n support the urethra , is decreased14 . in \n a normal support system , intra - abdominal pressure pushes the urethra against the \n hammock - like supportive layer , and the urethral lumen closes , which in turn does not allow \n urine to pass . however , in the case of an abnormal supportive layer , the lumen is not \n closed completely , thus resulting in urine leakage13 , 14 . \n the neural hypotheses : the main neural hypothesis for development of sui \n is associated with the pudendal nerve injury . \n so , any damage to the pudendal nerve ( e.g. , due to the recent vaginal \n delivery ) results in sui3 . \n in addition to the above mentioned hypothesis concerning ui , there are some risk factors \n that may result in the occurrence of sui . \n these are as follows : childbirth15 , 16 , age17 , \n decreased collagen content and elasticity18 , race and ethnicity15,16,17 , obesity17 , 19 , smoking , chronic cough , respiratory \n diseases20 , pelvic surgery17 , chronic constipation20 , and carbonated drinks19 . furthermore , there are also some nonspecific risk factors , such as pelvic organ \n prolapse21 , medications22 , fluid intake23 , fecal incontinence24 , and pelvic pain20 , that may result in sui . \n it is worth mentioning that the \n coexisting pelvic symptoms might be as follows : dual incontinence and pelvic organ \n prolapse , constipation , sexual dysfunction , chronic pelvic pain , low back pain , and hip \n pain8 . \n physiotherapy treatments for female sui include pelvic floor physiotherapy , lifestyle and \n behavioral therapy , and medication8 , 13 , 25,26,27 . \n pelvic floor physiotherapy : one of the most frequent treatments for sui \n is pelvic floor muscle exercise ( pfme ) or specifically contraction of the la muscle . \n the \n premise of this intervention is that strong la muscle contraction will improve urethral \n closure and pelvic organ support . \n it is hypothesized that compression of the urethra by \n contraction of the pelvic floor muscle will stop urine leakage if the contraction is of \n sufficient force and properly timed8 , 13 , 25,26,27 . \n it seems reasonable that la muscle exercise could increase the \n compression function of the muscle . \n since the la muscle consists of both type i ( slow \n twitch ) and type ii ( fast twitch ) muscle fibers , specific strength training exercises can \n affect type ii muscle fiber size through hypertrophy . \n thus , strengthening type ii fibers \n of the la muscle could aid the urethral sphincter in maintaining continence28 . \n pfmes such as kegel exercises are \n taught either by verbal instruction or manual palpation , and produce contraction of the la \n against intra - abdominal pressure . \n specifically , strengthening and coordination of the \n motor control of muscles that form the abdominal cavity walls and function as primary \n stabilizing musculature of the lumbosacral spine ( fig . \n 2.abdominal cavity wall , which functions as the primary stabilizing musculature of \n the lumbosacral spine and as a functional unit15 ) are the main focus of pfme29 , 30 . abdominal cavity wall , which functions as the primary stabilizing musculature of \n the lumbosacral spine and as a functional unit15 the effectiveness of pfme in women with sui is determined by both the frequency and \n intensity of exercise . performing 15 repetitions of 2 to 4 seconds of contraction in an \n exercise program with 3 sets per day for a period of 8 weeks , for instance , in women with \n mild to moderate \n this exercise program was also \n accompanied by instruction of the knack principle31 . \n the knack or counterbracing technique is taught by clinicians to \n prevent leakage during increases in abdominal pressure . \n the patient is taught to contract \n the pelvic floor muscle just prior to physical stresses such as sneezing . \n it is not clear , \n however , what contribution each intervention ( pfme or behavioral training utilizing the \n knack principle ) made to the reduction in sui in the patients . \n another limitation of this \n study is associated with the short time period for muscle training . \n normally , the maximal \n effect of strength training does not occur before 5 months of training31 . \n studies in which women were trained longer and in which the effect of pfme alone on \n reduction of sui was tested , reported favorable results . according to a cochrane review of \n pfme , greater improvements occur when women receive a supervised pfme program of at least \n three months8 . \n it seems also likely that \n physiotherapy treatment effectiveness would be enhanced if the exercise prescription is \n based on sound physiological principles . \n the studies mentioned in this review are \n consistent in incorporating both pfm endurance and strengthening principles8 . \n it is worth mentioning that in addition to considering the intensity and duration of a \n pfme program , physiotherapists may also need to consider the body position in which the \n women with sui exercise . \n borello - france et al . compared the efficacy of a pfme progression \n that included practice in upright positions ( i.e. , sitting and standing ) with the \n effectiveness of a pfme program that was performed only in the supine position in reducing \n sui . \n they showed that the position used for pfme was not an important factor in performing \n exercise and the resulting reduction in sui32 . \n further studies are needed to corroborate this finding \n concerning the positioning effects of pfme on sui . \n clinically , physiotherapists utilize exercise progression from gravity - eliminated to \n anti - gravity positions and finally an unstable base of support such as swiss ball exercise \n when strengthening the pfm ( fig . 3fig . \n 3.examples of exercise progression ( exercises progress from the top to bottom \n diagrams)15 ) . \n we should also keep in mind that according to the specificity theory on motor \n tasks , greater gains in motor performance occur when practice resembles a functional task \n as much as possible8 . \n examples of exercise progression ( exercises progress from the top to bottom \n diagrams)15 the main principles of therapeutic modalities used in physiotherapy for sui can be \n summarized as follows : pelvic floor muscle awareness is taught . \n the use of anticipatory pelvic floor muscle contraction immediately prior to an \n activity that causes urine leakage ( the knack principle ) is taught . a program of pfme is prescribed to individual patients and includes exercises for both \n fast and slow twitch muscle fibers . \n pfmes are performed until the muscle fatigues , several times a day , and for 12 to 20 \n weeks . \n patients are initially seen weekly , but their circumstances and/or the available \n resources may need to be taken into account . \n pfme along with biofeedback : correct contraction can be verified by \n biofeedback or manual palpation . in women \n , biofeedback can be obtained using small \n electrodes placed around the anus or by using an internal , vaginal electrode . \n based on the literature , pfme with biofeedback is not more effective than pfme alone . \n however , pfme along with biofeedback may be a clinically useful and acceptable treatment \n for some women . \n a practical strategy may be to initiate pfme with biofeedback for those \n who might have difficulty in understanding how to contract or are unable to contract the \n pfm33 . \n pfme and electrical stimulation : electrical stimulation ( es ) is another \n intervention used by physiotherapists to reduce ui . \n the physiological objectives of es are \n to produce muscle hypertrophy , to normalize the reflex activity of the lower urinary \n tract , and to increase circulation to muscles and the capillary system25 , 27 , 34 . \n it may also increase conscious awareness of the \n action of these muscles to yield an improved ability to perform a voluntary muscle \n contraction . with regard to a recent systematic review \n , es did not differ from sham stimulation or \n pfme in terms of ui improvement35 . \n however , es is a priority for women with difficulty in contracting the pfm initially . \n needless to say , substituting pfme alone for es needs to be considered in the treatment \n protocol25 , 27 . \n cone therapy : cone therapy can be a useful exercise and can be used as a \n biofeedback device using vaginal cones even in patients without a palpable voluntary \n contraction25 . \n there are no studies , to our knowledge , applying pfm training for primary prevention of \n sui . \n theoretically , it is estimated that strengthening the pfm by specific training would \n have the potential to prevent sui and pelvic organ prolapse . \n strength training may \n increase the pfm volume and lift the levator plate to a more cranial level inside the \n pelvis . \n if the pelvic floor possesses certain amount of stiffness , it is likely that the \n muscles could counteract the increases in abdominal pressures that occur during physical \n exertion . \n the few studies published on prevention have concentrated on training during \n pregnancy or after childbirth26 , 36 , 37 . \n the researchers showed that continent women had a significantly \n stronger pfm than incontinent women . \n two other studies did not show any effect of pfm \n training during pregnancy or after childbirth38 , \n 39 . \n the interventions in these two \n studies were , however , weak , as the programs only consisted of one session with a midwife \n or a physiotherapist , respectively . \n normally , women with sui receive physiotherapy treatment once a week for a period of 4 to \n 8 weeks . instruction and performance of pfme at home are supplemented by a physiotherapy \n program . \n thus , physiotherapy treatment when accompanied by a prescribed home exercise is \n likely to be successful for sui treatment \n . additionally , factors such as education , \n activity level , parity , smoking , child delivery type , and pelvic pain may affect the \n ability to correctly perform pfme38 , 40 . \n conclusion : from these observations , we concluded that the plan for \n physiotherapy care should be individualized for each patient and include standard \n physiotherapy interventions . \n as outlined in table \n 1table 1.intervention categories with evidence - based references of justification \n notedmodalitiesheat41ice41pfm biofeedback33 , 34 to promote strength and endurance to increase coordination to promote muscle relaxationpfm electrical stimulation31 , 34 to improve pfm strength ( if 2/5 pfm strength) to promote sensory awareness due to sensory \n impairment to reduce painmanual physiotherapy proceduressoft tissue mobilization to decrease soft tissue \n restriction and improve range of motion42 , 43joint \n mobilization to improve range of motion44exercisespfme32 , 33 , 45 , 46 manual facilitation gravity eliminated anti - gravity during functional tasks down trainingcore stabilization47 , 48 transverse abdominis muscle other abdominal muscles multifidus muscle functional exercisesflexibility hip41 lumbopelvic49educationbody mechanics / posture44bladder / bowel schedule50diet modification caffeine reduction51 carbonated beverage reduction51 increase water intake52 decrease water intake53 fiber education52relaxation techniques to decrease muscle \n tension54sui strategies such as pfm contraction before \n increase in intra - abdominal pressure55uui strategies such as inhibition techniques to \n suppress bladder contractions56toilet strategies for constipation such as toilet posture to promote \n bowel movement57 voiding without strainingsoft tissue massage such as abdominal massage , scar \n massage , and self - stretching for introitus34 , 43 , 57 , these interventions include modalities to decrease pain , pfme with or \n without biofeedback and/or electrical stimulation to improve strength and coordination of \n the pfm , stabilization exercises to improve strength of abdominal and/or lumbar stabilizer \n muscles , and patient education including recommendations for bladder and/or bowel \n training , fluid management , and diet modification12 . \n the pelvic floor \n is composed of striated muscles arranged in a dome - shaped sheet and is often described as \n a sling . \n these muscles are referred to as lying within either the deep or supercial \n pelvic floor . \n the fascia and muscles of the pelvic floor support the bladder , uterus , and \n rectum . \n muscles specic to the deep pelvic oor include the levator ani ( la ) and \n ischiococcygeus . \n the la is composed of three muscle bellies , including the iliococcygeus , \n pubococcygeus , and puborectalis . \n the iliococcygeal and pubococcygeal muscles form a \n horizontal shelf or hammock that spans from one pelvic sidewall to the other and then \n attaches laterally to the ischial spines and arcus tendineus fascia . \n the puborectalis \n muscle arises from the pubic bone on either side and extends into a sling or u - shape \n around the posterior rectum , which attaches to the walls of the vagina , urethra , and \n rectum13 , 14 ( fig . \n these include the \n anterior bers of the la , the transverses perinea supercialis and profundus , \n bulbospongiosus , external anal sphincters , and bers from urinary sphincters13 ( fig . \n 1 ) . \n the collective group of the la and coccygeus muscles with the surrounding \n fascia is referred to as the diaphragm of the pelvis . \n although it is poorly discussed , the \n pelvic oor has an important role in the function of core muscle stabilization . \n the core \n muscles are known as the muscles of the trunk ( abdominals , quadrates lumborum , spinal \n muscles including the multidus , and hip muscles ) , the diaphragm , and the pelvic oor . \n essentially , the pelvic oor is the oor of the core14 . \n the opening between the la through which the urethra , vagina , and rectum pass is the \n urogenital hiatus . \n the urogenital hiatus is anteriorly supported by the pubic bones and la \n and posteriorly by the perineal membrane and external anal sphincter . \n the perineal membrane is a dense triangular membrane located below the la with a central \n opening through which the vagina and urethra pass . \n the anatomy of the continence system can be organized into those structures that provide \n normal support to the lower urinary tract , and those that determine urethral closure \n force . \n the structures that provide normal support include the three layers of the pelvic \n floor structure . during bladder storage , activation of the sympathetic nervous \n system increases the tonic \n activity or contraction of the internal urethral sphincter to assist in preventing urine \n leakage . \n the lower urinary tract is innervated by three sets of peripheral nerves including ( i ) \n pelvic parasympathetic nerves ( s2-s4 segments ) that excite the bladder , ( ii ) lumbar \n sympathetic nerves that inhibit the bladder and excite the internal urethral sphincter , \n and ( iii ) pudendal nerves that excite the external urethral sphincter and pelvic floor \n muscles13 , 14 . \n the main anatomic hypotheses for development of sui are as follows : 1 ) the loss of \n structural support , 2 ) the hammock , and 3 ) the neural hypotheses3 . \n loss of structural support hypotheses : supportive structures to the \n bladder neck and urethra are necessary to maintain urethral closure pressure . \n intact \n attachments of the suburethral fascia to the fascia of the arcus tendineus and the la \n construct a firm shelf that remains stable when faced with increased forces generated by a \n cough or sneeze14 . \n disruption of this \n shelf , such as weakness of the la or damage to fascial attachments , as described in the \n loss of structural support hypotheses , could result in sui . aging and childbirth injury \n are considered the main etiological factors for la weakness14 . \n the hammock hypotheses : in this hypothesis , the position of the urethra \n remains constant , but the compression of the pelvic floor muscles and fascia , which \n support the urethra , is decreased14 . in \n a normal support system , intra - abdominal pressure pushes the urethra against the \n hammock - like supportive layer , and the urethral lumen closes , which in turn does not allow \n urine to pass . \n however , in the case of an abnormal supportive layer , the lumen is not \n closed completely , thus resulting in urine leakage13 , 14 . the neural hypotheses : the main neural hypothesis for development of sui \n so , any damage to the pudendal nerve ( e.g. , due to the recent vaginal \n delivery ) results in sui3 . \n in addition to the above mentioned hypothesis concerning ui , there are some risk factors \n that may result in the occurrence of sui . \n these are as follows : childbirth15 , 16 , age17 , \n decreased collagen content and elasticity18 , race and ethnicity15,16,17 , obesity17 , 19 , smoking , chronic cough , respiratory \n diseases20 , pelvic surgery17 , chronic constipation20 , and carbonated drinks19 . furthermore , there are also some nonspecific risk factors , such as pelvic organ \n prolapse21 , medications22 , fluid intake23 , fecal incontinence24 , and pelvic pain20 , that may result in sui . \n it is worth mentioning that the \n coexisting pelvic symptoms might be as follows : dual incontinence and pelvic organ \n prolapse , constipation , sexual dysfunction , chronic pelvic pain , low back pain , and hip \n pain8 . \n physiotherapy treatments for female sui include pelvic floor physiotherapy , lifestyle and \n behavioral therapy , and medication8 , 13 , 25,26,27 . \n pelvic floor physiotherapy : one of the most frequent treatments for sui \n is pelvic floor muscle exercise ( pfme ) or specifically contraction of the la muscle . the \n premise of this intervention is that strong la muscle contraction will improve urethral \n closure and pelvic organ support . \n it is hypothesized that compression of the urethra by \n contraction of the pelvic floor muscle will stop urine leakage if the contraction is of \n sufficient force and properly timed8 , 13 , 25,26,27 . \n it seems reasonable that la muscle exercise could increase the \n compression function of the muscle . \n since the la muscle consists of both type i ( slow \n twitch ) and type ii ( fast twitch ) muscle fibers , specific strength training exercises can \n affect type ii muscle fiber size through hypertrophy . \n thus , strengthening type ii fibers \n of the la muscle could aid the urethral sphincter in maintaining continence28 . \n pfmes such as kegel exercises are \n taught either by verbal instruction or manual palpation , and produce contraction of the la \n against intra - abdominal pressure . specifically , strengthening and coordination of the \n motor control of muscles that form the abdominal cavity walls and function as primary \n stabilizing musculature of the lumbosacral spine ( fig . \n 2.abdominal cavity wall , which functions as the primary stabilizing musculature of \n the lumbosacral spine and as a functional unit15 ) are the main focus of pfme29 , 30 \n . abdominal cavity wall , which functions as the primary stabilizing musculature of \n the lumbosacral spine and as a functional unit15 the effectiveness of pfme in women with sui is determined by both the frequency and \n intensity of exercise . performing 15 repetitions of 2 to 4 seconds of contraction in an \n exercise program with 3 sets per day for a period of 8 weeks , for instance , in women with \n mild to moderate \n this exercise program was also \n accompanied by instruction of the knack principle31 . \n the knack or counterbracing technique is taught by clinicians to \n prevent leakage during increases in abdominal pressure . \n the patient is taught to contract \n the pelvic floor muscle just prior to physical stresses such as sneezing . \n it is not clear , \n however , what contribution each intervention ( pfme or behavioral training utilizing the \n knack principle ) made to the reduction in sui in the patients . \n another limitation of this \n study is associated with the short time period for muscle training . \n normally , the maximal \n effect of strength training does not occur before 5 months of training31 . \n studies in which women were trained longer and in which the effect of pfme alone on \n reduction of sui was tested , reported favorable results . according to a cochrane review of \n pfme , \n greater improvements occur when women receive a supervised pfme program of at least \n three months8 . \n it seems also likely that \n physiotherapy treatment effectiveness would be enhanced if the exercise prescription is \n based on sound physiological principles . \n the studies mentioned in this review are \n consistent in incorporating both pfm endurance and strengthening principles8 . \n it is worth mentioning that in addition to considering the intensity and duration of a \n pfme program , physiotherapists may also need to consider the body position in which the \n women with sui exercise . \n borello - france et al . compared the efficacy of a pfme progression \n that included practice in upright positions ( i.e. , sitting and standing ) with the \n effectiveness of a pfme program that was performed only in the supine position in reducing \n sui . \n they showed that the position used for pfme was not an important factor in performing \n exercise and the resulting reduction in sui32 . \n further studies are needed to corroborate this finding \n concerning the positioning effects of pfme on sui . \n clinically , physiotherapists utilize exercise progression from gravity - eliminated to \n anti - gravity positions and finally an unstable base of support such as swiss ball exercise \n when strengthening the pfm ( fig . 3fig . \n 3.examples of exercise progression ( exercises progress from the top to bottom \n diagrams)15 ) . \n we should also keep in mind that according to the specificity theory on motor \n tasks , greater gains in motor performance occur when practice resembles a functional task \n as much as possible8 . \n examples of exercise progression ( exercises progress from the top to bottom \n diagrams)15 the main principles of therapeutic modalities used in physiotherapy for sui can be \n summarized as follows : pelvic floor muscle awareness is taught . \n the use of anticipatory pelvic floor muscle contraction immediately prior to an \n activity that causes urine leakage ( the knack principle ) is taught . \n a program of pfme is prescribed to individual patients and includes exercises for both \n fast and slow twitch muscle fibers . \n pfmes are performed until the muscle fatigues , several times a day , and for 12 to 20 \n weeks . \n patients are initially seen weekly , but their circumstances and/or the available \n resources may need to be taken into account . \n pfme along with biofeedback : correct contraction can be verified by \n biofeedback or manual palpation . in women \n , biofeedback can be obtained using small \n electrodes placed around the anus or by using an internal , vaginal electrode . \n based on the literature , pfme with biofeedback is not more effective than pfme alone . \n however , pfme along with biofeedback may be a clinically useful and acceptable treatment \n for some women . \n a practical strategy may be to initiate pfme with biofeedback for those \n who might have difficulty in understanding how to contract or are unable to contract the \n pfm33 . \n pfme and electrical stimulation : electrical stimulation ( es ) is another \n intervention used by physiotherapists to reduce ui . the physiological objectives of es are \n to produce muscle hypertrophy , to normalize the reflex activity of the lower urinary \n tract , and to increase circulation to muscles and the capillary system25 , 27 , 34 . \n it may also increase conscious awareness of the \n action of these muscles to yield an improved ability to perform a voluntary muscle \n contraction . with regard to a recent systematic review , \n es did not differ from sham stimulation or \n pfme in terms of ui improvement35 . \n however , es is a priority for women with difficulty in contracting the pfm initially . \n needless to say , \n substituting pfme alone for es needs to be considered in the treatment \n protocol25 , 27 . \n cone therapy : cone therapy can be a useful exercise and can be used as a \n biofeedback device using vaginal cones even in patients without a palpable voluntary \n contraction25 . \n there are no studies , to our knowledge , applying pfm training for primary prevention of \n sui . \n theoretically , it is estimated that strengthening the pfm by specific training would \n have the potential to prevent sui and pelvic organ prolapse . \n strength training may \n increase the pfm volume and lift the levator plate to a more cranial level inside the \n pelvis . \n if the pelvic floor possesses certain amount of stiffness , it is likely that the \n muscles could counteract the increases in abdominal pressures that occur during physical \n exertion . \n the few studies published on prevention have concentrated on training during \n pregnancy or after childbirth26 , 36 , 37 . \n the researchers showed that continent women had a significantly \n stronger pfm than incontinent women . \n two other studies did not show any effect of pfm \n training during pregnancy or after childbirth38 , \n 39 . \n the interventions in these two \n studies were , however , weak , as the programs only consisted of one session with a midwife \n or a physiotherapist , respectively . \n normally , women with sui receive physiotherapy treatment once a week for a period of 4 to \n 8 weeks . instruction and performance of pfme at home are supplemented by a physiotherapy \n program . thus , physiotherapy treatment when accompanied by a prescribed home exercise is \n likely to be successful for sui treatment . \n additionally , factors such as education , \n activity level , parity , smoking , child delivery type , and pelvic pain may affect the \n ability to correctly perform pfme38 , 40 . \n conclusion : from these observations , we concluded that the plan for \n physiotherapy care should be individualized for each patient and include standard \n physiotherapy interventions . as outlined in table \n 1table 1.intervention categories with evidence - based references of justification \n notedmodalitiesheat41ice41pfm biofeedback33 , 34 to promote strength and endurance to increase coordination to promote muscle relaxationpfm electrical stimulation31 , 34 to improve pfm strength ( if 2/5 pfm strength) to promote sensory awareness due to sensory \n impairment to reduce painmanual physiotherapy proceduressoft tissue mobilization to decrease soft tissue \n restriction and improve range of motion42 , 43joint \n mobilization to improve range of motion44exercisespfme32 , 33 , 45 , 46 manual facilitation gravity eliminated anti - gravity during functional tasks down trainingcore stabilization47 , 48 transverse abdominis muscle other abdominal muscles multifidus muscle functional exercisesflexibility hip41 lumbopelvic49educationbody mechanics / posture44bladder / bowel schedule50diet modification caffeine reduction51 carbonated beverage reduction51 increase water intake52 decrease water intake53 fiber education52relaxation techniques to decrease muscle \n tension54sui strategies such as pfm contraction before \n increase in intra - abdominal pressure55uui strategies such as inhibition techniques to \n suppress bladder contractions56toilet strategies for constipation such as toilet posture to promote \n bowel movement57 voiding without strainingsoft tissue massage such as abdominal massage , scar \n massage , and self - stretching for introitus34 , 43 , 57 , these interventions include modalities to decrease pain , pfme with or \n without biofeedback and/or electrical stimulation to improve strength and coordination of \n the pfm , stabilization exercises to improve strength of abdominal and/or lumbar stabilizer \n muscles , and patient education including recommendations for bladder and/or bowel \n training , fluid management , and diet modification12 .", "role": "user" }, { "content": "[ purpose ] this review article is designed to expose physiotherapists to a physiotherapy \n assessment of stress urinary incontinence ( sui ) and the treatment and possibly preventive \n roles that they might play for women with sui . \n specifically , the goal of this article is \n to provide an understanding of pelvic floor muscle function and the implications that this \n function has for physiotherapy treatment by reviewing articles published in this area . \n [ methods ] a range of databases was searched to identify articles that address \n physiotherapy for sui , including the cochrane library , medline , and cinahl . \n [ results ] \n according to the articles identified in our databases research , greater improvements in \n sui occur when women receive a supervised exercise program of at least three months . \n the \n effectiveness of physiotherapy treatment is increased if the exercise program is based on \n some principles , such as intensity , duration , resembling functional task , and the position \n in which the exercise for pelvic floor muscles is performed . \n biofeedback and electrical \n stimulation may also be clinically useful and acceptable modalities for some women with \n sui . \n [ conclusion ] we concluded that the plan for physiotherapy care should be \n individualized for each patient and include standard physiotherapy interventions .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: the latissimus dorsi and gluteus maximus muscles are linked obliquely to the posterior \n spine by the thoracolumbar fascia , and this is referred to as the posterior oblique sling \n system1 . \n when walking , the muscles of \n the posterior oblique sling provide trunk stability for extension and work together to help \n deliver power from the lower body to the upper body . \n in addition , they are necessary for \n trunk stability for rotation and for promoting a mutual gait pattern between the upper and \n lower extremities2 . moreover , the \n contralateral gluteus maximus and latissimus dorsi are connected functionally via the \n thoracolumbar fascia . \n therefore , they contract together not only while running , but also \n during gait and axial movement of the trunk1 , 3 . \n the muscles of the posterior oblique sling \n are essential for promoting mutual gait patterns involving trunk stability and the lower and \n upper extremities . \n they also create joint contraction , not only in running but also in \n turning the trunk and in walking4 , 5 . \n it has also been suggested that the \n increased gait speed increases the angle of arm swing6 . \n however , few studies have examined the effect of a change in arm \n swing with gait speed on the activities of the latissimus dorsi and gluteus maximus via the \n posterior oblique sling system . therefore , this study examined the effect of arm swing at \n different gait speeds in terms of improvement of both gait function and indirect lower \n extremity muscle activity via the posterior oblique sling system , as it relates to the \n latissimus dorsi and gluteus maximus . \n the subjects of this study were 14 young adult males who voluntarily consented to \n participate in the study and had no history of disease or any problem with walking . \n their \n average age , height and weight were 28.36 4.31 years , 174.84 6.6 cm and 74.52 7.9 kg , \n respectively . \n surface emg was used to collect raw emg data using a trigno wireless system \n ( delsys , boston , ma , usa ) . \n the sampling rate of the emg signal was 2,000 samples / s using a \n band - pass of 20450 hz . \n two surface electrodes \n were placed on following muscles : the left ( nondominant side ) latissimus dorsi ( lateral to \n the t9 spinous process over the muscle belly ) and right ( dominant side ) gluteus maximus ( the \n midpoint of a line running from the last sacral vertebrae to the greater trochanter)7 . \n emg data were normalized using the maximum \n voluntary isometric contraction ( mvic ) of each muscle measured using the manual muscle test \n as described by kendall et al8 . \n all \n subjects walked on a treadmill at speeds of 1.5 km / h , 3.5 km / h , and 5.5 km / h for 30 seconds . \n the left latissimus dorsi , and right gluteus maximus muscle \n activities were measured in subject while walking on the treadmill . \n the emg signal was \n collected for 30 seconds , and the first and last 5 seconds were discarded . \n the data were \n analyzed using one - way repeated - measures analysis of variance ( anova ) . \n all \n significance levels were p<0.05 , and spss version 20.0 ( ibm , armonk , ny , usa ) was used \n for the statistical analyses . \n there was a significant increase in latissimus dorsi muscle activity with a treadmill speed \n of 5.5 km / h compared with 1.5 km / h and 3.5 km / h ( p<0.05 ) . \n the gluteus maximus muscle \n activity significantly increased in the order of 1.5 km / h < 3.5 km / h < 5.5 km / h \n ( p<0.05 ) ( table 1table 1 . \n comparison of normalized emg data of the two muscles at each treadmill \n speedmusclesmean sd ( % mvc)1.5 km / h3.5 km / h5.5 km / hlatissimus dorsi9.4 5.111.1 6.913.3 \n this study investigated the changes in the activities of the latissimus dorsi and gluteus \n maximus muscles , as related to the posterior oblique sling system , with changing gait speed . \n a study of children with cerebral palsy showed that \n increased arm swing is significantly related to gait speed9 . \n in addition , ford et al . suggested that rotation of the trunk and \n pelvis is decreased when arm swing is limited and that gait speed increases due to increased \n cooperation between the upper and lower extremities when there is no limitation10 . \n consequently , it turns out that the \n change of angle in arm swing due to increased speed affects gluteus maximus and latissimus \n dorsi activity via the posterior oblique sling system during walking . \n one study in which one \n or both arms were limited suggested that the maximum gait speed was decreased , stride \n frequency was increased , and stride length was decreased11 . \n this means that arm swing during walking can affect the movement \n of the lower extremity , which is similar to our result , suggesting that muscle activity in \n the upper extremity can affect that of the lower extremity as arm swing increases . \n these \n results indicate that arm swing connected to increasing gait speed influences lower limb \n muscle activity via the posterior oblique sling system .", "role": "user" }, { "content": "[ purpose ] this study investigated the effect of different gait speeds on the muscle \n activities of the latissimus dorsi and gluteus maximus muscles in relation to the \n posterior oblique sling system . \n [ subjects ] we recruited 14 young adult males . [ methods ] we \n measured the left latissimus dorsi muscle activity and right gluteus maximus muscle \n activity of all subjects while they walked on a treadmill at speeds of 1.5 km / h , 3.5 km / h \n and 5.5 km / h . [ results ] there was a significant increase in latissimus dorsi muscle \n activity with a treadmill speed of 5.5 km / h compared with 1.5 km / h and 3.5 km / h . \n the \n gluteus maximus muscle activity significantly increased in the order of 1.5 km / h < \n 3.5 km / h < 5.5 km / h . \n [ conclusion ] the present results indicate that arm swing connected \n to increasing gait speed influences the muscle activity of the lower limbs through the \n posterior oblique sling system .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: diabetes mellitus is the most important risk factor for coronary artery disease ( cad ) . \n type 2 diabetes mellitus ( dm2 ) has reached epidemic proportions globally , affecting populations of both developed and developing countries . \n cad is often asymptomatic in dm2 patients until the onset of myocardial infarction or sudden cardiac death . \n it has been widely demonstrated that acute cardiac events are related to rupture and acute thrombosis caused by a mildly stenotic plaque , namely , the vulnerable plaque . \n conventional x - ray coronary angiography is the current gold standard for invasive evaluation of cad . \n however , it only shows the lumen of the vessel , greatly underestimating the atherosclerosis burden . a noninvasive assay to directly detect coronary atherosclerosis would therefore be beneficial . \n coronary cta provides comprehensive information noninvasively regarding the location , severity , and characteristics of coronary atherosclerotic plaques : noncalcified , calcified , and mixed plaques can be identified . \n a previous study showed that vulnerable plaques in diabetic patients tend to occur at multiple sites , with high atherosclerotic burden . \n the most widely tested inflammatory biomarker is high - sensitivity c - reactive protein ( hs - crp ) , which predicts the risk of a first mi in healthy individuals and future coronary events in patients with stable cad . \n it is well known that both elevated crp and specific plaque subtypes are associated with poor disease outcome [ 8 , 9 ] . \n understanding how crp and vulnerable plaques are related and using imaging techniques to assess this relationship may enable the early identification of vulnerable patients . \n recently , in a cohort of asymptomatic subjects , increased crp levels were found to be associated with the prevalence of any plaque and mixed calcified plaques , as well as significant coronary stenosis . to the best of our knowledge \n therefore , we aimed to assess the relationship between hs - crp levels and plaque subtypes in symptomatic patients with dm2 using 256-slice ct . \n from december 2013 to december 2014 , 205 patients underwent 256-slice ct coronary angiography , including 98 dm2 cases and 107 individuals without dm2 . \n they were 108 men and 97 women , 48 15 years old , with bmi of 22.15 2.36 \n exclusion criteria were heart rate 90 bpm , atrial fibrillation , severe renal insufficiency ( serum creatinine > 120 mol / l ) , severe respiratory insufficiency , hyperthyroidism , and allergy to iodine - based contrast . \n the study was approved by the institutional review board of the hospital , and informed consent was obtained from each patient . \n cta examinations were performed on a 256-slice ct ( brilliance ict ; philips , amsterdam , netherlands ) and a power injector ( sct-211 ; medrad inc . , indianola , pa , usa ) . \n the scan protocols were as follows : detector width , 80 mm ; detector collimation , 128 0.625 mm ; slice acquisition , 128 0.625 mm using a z - flying focal spot ; gantry rotation time , 0.27 s. tube voltage and current were set at 300500 mas per rotation and 120140 kvp , respectively . the contrast material ( ultravist solution 370 mg i / ml ; bayer healthcare , berlin , germany ) was intravenously injected through an antecubital vein using a 20-gauge needle connected to a power injector ( sct-211 \n contrast material injection timing was controlled by the bolus - tracking technique in the ascending aorta ( signal attenuation threshold 100120 hounsfield units [ hu ] ) . \n data acquisition was initiated with a mean delay of 6 s after reaching the threshold in the ascending aorta . a total amount of 6080 ml of contrast material was injected at 5 ml / s followed by 30 ml of saline chaser . \n the mean effective radiation dose of the coronary cta was 1.58 0.36 msv . \n all scans were analyzed independently by two experienced radiologists blinded to the clinical information , on a brilliance workstation ( philips healthcare , amsterdam , netherlands ) . \n each lesion was identified using the multiplanar reconstruction technique and free mode maximum intensity projection . \n the 15 coronary segments were defined according to american heart association ( aha ) standards . \n lesions were classified by the maximal luminal stenosis observed on any plane ; grading of stenosis was further classified as normal appearing ( < 25% ) and mild ( 25%49% ) and moderate ( 50%74% ) and severe ( 75% ) narrowing . \n plaques occupied by calcified tissue > 50% of the plaque area ( density > 130 hounsfield units in native scans ) were classified as calcified arterial plaques ( cap ) ; those with < 50% calcium were considered mixed calcified arterial plaques ( mcap ) ; and plaques without calcium were classified as noncalcified arterial plaques ( ncap ) as previously described ( figure 1 ) . \n continuous variables are mean standard deviation ( sd ) and categorical variables as number and percentage . \n the extent and types of plaque as well as luminal narrowing were evaluated and compared between diabetic and nondiabetic patients . \n the patients were further divided into 3 groups according to median hs - crp levels : low / normal group ( hs - crp 1 \n mg / l ) , intermediate group ( 1 mg / l < hs - crp 2 \n mg / l ) , and high group ( > 2 mg / l ) . \n multivariate logistical regression analysis was performed to explore the relationship between diabetes , crp , and type and extent of plaque . \n statistical analyses were performed with the spss 18.0 software ( spss , chicago , il , usa ) . \n the patients were 48 15 years old and included 52.7% men ; body mass index values were 22.15 2.36 kg / m . \n the average dm2 duration was 8.5 7.8 years . compared with subjects without dm2 , no significant differences in the levels of total cholesterol , triglyceride , high - density lipoprotein cholesterol , and low - density lipoprotein cholesterol \n a total of 432 coronary vessels ( 4.3 0.18 per patient ) and 820 segments ( 8.2 0.06 per patient ) had plaques . in total , \n calcified plaques ( 54.7% ) were more frequently detected than mixed or noncalcified ones ( p < 0.001 ) . \n the most commonly affected coronary vessel was the lad artery in both groups : 40.4% lad , 27.1% rca , 18.3% lcx , and 14.2% lm were diseased in diabetics , with 39.0% lad , 32.1% rca , 18.2% lcx , and 10.7% lm in nondiabetic patients ( all p < 0.001 ) . \n 262 diseased coronary vessels with 453 affected segments were found in diabetic patients , whereas 170 diseased coronary vessels and 367 affected segments were observed in nondiabetic individuals . \n diffuse vessel disease was more commonly detected in dm2 patients than nondiabetic subjects ( 31.6% versus 4.7% ; p < 0.01 ) . in addition \n , more diseased segments were found in patients with diabetes ( 8.23 4.48 ) compared with nondiabetic subjects ( 3.67 2.42 , p < 0.05 ) . \n furthermore , cad tended to be more severe in dm2 patients as both left main / lad coronary artery and multivessel diseases were more frequently diagnosed , although the difference was not statistically significant . \n more calcified plaques and less noncalcified plaques were detected in diabetics compared with nondiabetic patients , respectively ( 72.9% versus 48.1% , p < 0.001 ; 27.1% versus 51.9% , p < 0.001 ) . as dm2 disease time increased from 5 to 10 and 10 to 15 years \n , the proportion of calcified plaques increased , with that of noncalcified plaques decreasing significantly ( 63.1% versus 24.0% , p < 0.001 ) . \n obstructive plaques were more abundant in diabetic patients compared with nondiabetics ( 28.3% versus 7.6% , p < 0.05 ) . the plaque burden and stenosis data are shown in table 2 . \n figure 2 depicts the prevalence of any coronary plaque subtype according to the various crp cutoffs . \n subjects with high crp levels were more likely to have any plaque , cap , or ncap compared with individuals showing normal crp levels ( p < 0.01 ) . \n plasma crp levels were significantly higher in individuals with dm2 compared with controls ( 3.232 0.327 \n figure 3 shows a symptomatic dm2 patient with increased crp , in whom coronary cta revealed triple vessel disease with diffuse calcified plaques . \n both the unadjusted and the multivariable logistic regression analyses for the presence of any coronary plaque and plaque subtype are listed in table 3 . \n subjects were divided into groups according to crp levels , and all analyses were performed using the low - normal crp group as the reference category . \n subjects with high crp were observed to be at increased risk for the presence of cap in the unadjusted values ( odds ratio [ or ] , 2.761 ; 95% confidence interval [ ci ] , 2.673 to 5.893 ) and the adjusted model 1 ( odds ratio [ or ] , 3.056 ; 95% confidence interval [ ci ] , 1.494 to 6.228 ) . no difference was observed in the risk for ncap or mcap for the unadjusted values . when examining the presence of a specific plaque subtype \n , subjects with crp had no increased risk for the presence of any type of plaque for the adjusted values . \n in the present study , differences in coronary plaque characteristics and plasma hs - crp levels between symptomatic dm2 patients and nondiabetics were observed . \n we also demonstrated that elevated hs - crp levels were associated with increased risk for plaque formation , including cap and ncap . \n significantly more diffuse cap were present in symptomatic dm2 patients compared with nondiabetics , indicating that the presence of diffused calcium is associated with greater atheroma burden , in agreement with previous reports [ 4 , 11 ] . \n traditionally , calcified plaque is considered an established , stable , and quiescent atheroma . however , in several cross - sectional studies in patients with acute coronary syndrome , spotty calcification is associated with culprit lesions [ 1214 ] . \n multiple studies also demonstrated that the presence of coronary artery calcification in asymptomatic individuals is a predictor of future cardiac events [ 1517 ] . \n clearly , plaque calcification represents a dynamic process related to oxidized lipids and inflammatory activity . \n the natural history of atherosclerosis is considered a dynamic process varying from early lesion development to more advanced plaques . in our study \n , we demonstrate that elevated levels of crp are associated with increased risk for the presence of any plaque and cap , but not ncap or mcap ; patients with symptomatic dm2 were more likely to have significant stenosis with cap in at least one coronary segment . \n our findings may indicate a more rapid atherosclerosis development in diabetics , with a faster progression from noncalcified to completely calcified lesions . \n coronary cta provides data regarding the coronary tree and atherosclerotic plaques beyond simple luminal narrowing and plaque type defined by calcium content . \n compared with calcium score analysis , coronary cta data sets provide submillimeter isotropic spatial resolution , and the possibility of ct attenuation based tissue characterization enables the quantification of total coronary plaque burden and individual plaque components . if the high - risk plaques reported in this study are indeed important for prognosis , coronary cta would be a potential candidate screening tool , since it might identify silent vulnerable plaques not otherwise detected by functional imaging . \n chronic inflammation plays a major role in all phases of atherosclerosis , and dm2 presence and development are associated with subclinical systemic inflammation . in this study , we found that severe stenosis rates and hs - crp levels were significantly higher in symptomatic dm2 patients . \n it has been clearly demonstrated that both elevated hs - crp levels and specific plaque subtypes are associated with poor cardiovascular outcomes . \n our findings may help understand how hs - crp and vulnerable plaques are related , also showing that coronary cta enables the assessment of such relationship . \n first , it remains unclear whether coronary calcification predicts plaque instability or is merely a marker of plaque burden . \n second , because we categorized coronary plaque subtypes into ncap , mcap , and cap as opposed to quantifying in a continuous manner the burden of calcified and noncalcified plaque components , there is a chance of misclassification . \n finally , although our analysis reflects the relationship between diffused calcification and elevated levels of hs - crp in patients with diabetes , the resultant impact on clinical outcome remains to be determined . \n future studies are required to determine the prognostic role of this methodology in patients with dm2 . in conclusion , \n combination of coronary cta and hs - crp might incrementally improve risk stratification in dm2 patients . \n future prospective studies are needed to establish the association between the presence of cap and acute coronary events .", "role": "user" }, { "content": "little is known regarding plaque distribution , composition , and the association with inflammation in type 2 diabetes mellitus ( dm2 ) . \n this study aimed to assess the relationship between coronary plaque subtypes and high - sensitivity c - reactive protein levels . \n coronary cta were performed in 98 symptomatic dm2 patients and 107 non - dm2 patients using a 256-slice ct . \n the extent and types of plaque as well as luminal narrowing were evaluated . \n patients with dm2 were more likely to have significant stenosis ( > 50% ) with calcified plaques in at least one coronary segment ( p < 0.01 ) ; the prevalence rates of diffuse calcified plaques in the dm2 and non - dm2 groups were 31.6% and 4.7% , respectively ( p < 0.01 ) . \n plasma hs - crp levels in dm2 with calcified plaques were higher compared with values obtained for the non - dm2 group ( p < 0.01 ) . in conclusion , combination of coronary cta and hs - crp might improve risk stratification in symptomatic dm2 patients .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: in england , surveillance for stis is conducted through mandatory reporting in sexual health clinics ( shcs ) ( genitourinary medicine [ gum ] and integrated gum / sexual and reproductive health clinics ) by using the gum clinic activity dataset version 2 ( gumcadv2 ) ( 3 ) . \n shcs provide free and open access services and , since 2012 , all ( 216 in 2014 ) have submitted data to public health england . \n although stis are not notifiable diseases in the united kingdom , gumcadv2 is a comprehensive , patient - level dataset of all attendances and laboratory - confirmed stis at shcs . \n information about the sexual orientation of each attendee is collected through gumcadv2 ( completion > 90% since 2011 ) ; this information was also collected by the preceding system , the kc60 aggregate return ( 3 ) . \n we reviewed the most recent gumcadv2 data , extracted on april 28 , 2015 , to assess trends in laboratory - confirmed gonorrhea , infectious ( primary / secondary / early latent ) syphilis , chlamydia , genital herpes ( first episode ) , and genital warts ( first episode ) . \n only 1 diagnosis of each sti was counted within a 6-week period ; this restriction also applies to instances of infection at multiple anatomic sites ( 3 ) . \n these data represent the number of diagnoses reported , not the number of persons in whom the infections were diagnosed . \n descriptive analyses by demographic characteristics and tests for linear trend were performed ; p values < 5% were considered significant . since 2013 , syphilis diagnoses among msm increased by 46% ( from 2,375 to 3,477 ) ; this increase is the largest year - on - year increase in syphilis diagnoses among msm since 2005 ( figure 1 ; table 1 ) . \n relative to 2013 , in 2014 the number of syphilis diagnoses among heterosexual men and men of unknown sexual orientation decreased by 0.2% ( from 578 to 577 ) , with a larger decrease in women ( 7.1% , from 283 to 263 ) ( table 1 ) . \n * genitourinary medicine ( gum ) and integrated gum / sexual and reproductive health clinics . in 2014 unknown sexual orientation \n figures for women who have sex with women are not reported here because in 2014 , homosexuality was reported for < 0.5% of women . \n msm , men who have sex with men ; non - msm men , heterosexual men and men of unknown sexual orientation ; sti , sexually transmitted infection . from 2013 to 2014 , diagnoses of gonorrhea among msm increased 32% ( from 13,629 to 18,029 ) ( figure 1 ; table 1 ) . \n although this increase was relatively large , it is consistent with the increasing trend from 2005 ( 3,817 diagnoses ; p = 0.015 ) . \n compared with the increased diagnoses in msm since 2013 , in 2014 the increases in gonorrhea diagnoses among heterosexual men and men of unknown sexual orientation ( 5.2% , from 8,122 to 8,546 ) and women ( 9.3% , from 7,664 to 8,379 ) were smaller ( table 1 ) . \n relative to 2013 , in 2014 , diagnoses further increased for chlamydia ( 25.8% ) , genital herpes ( 10.1% ) , and genital warts ( 9.5% ) among msm , consistent with the increasing trend since 2005 ( figure 1 ; table 1 ) . \n diagnoses of chlamydia decreased among heterosexual men and men of unknown sexual orientation ( 0.4% , from 44,512 to 44,339 ) and increased among women ( 4.9% , from 48,642 to 51,045 ) . \n genital herpes diagnoses decreased by 4.8% ( from 10,938 to 10,415 ) and 0.9% ( from 20,069 to 19,883 ) and genital warts by 5.2% ( from 37,872 to 35,893 ) and 4.8% ( from 32,834 to 31,251 ) among heterosexual men and men of unknown sexual orientation and among women , respectively . \n although the number of sexual health screen ( tests for chlamydia , gonorrhea , hiv , and syphilis ) among msm increased 29% from 2013 to 2014 , the rates ( diagnoses/1,000 screenings ) of syphilis and gonorrhea increased 13.8% ( from 20.9 to 23.8 ) and 2.9% ( from 120.2 to 123.6 ) , respectively . \n the rate ( diagnosis/1,000 screenings ) of chlamydia decreased 2.2% ( from 80.4 to 78.6 ) ( figure 2 ) , and the proportion of diagnoses of extragenital chlamydia and gonorrhea also decreased ( figure 2 ) . \n rate of diagnoses ( per 1,000 sexual health screens ) of chlamydia , gonorrhea , and syphilis ( primary , secondary , and early latent ) and proportion of extragenital chlamydia and gonorrhea diagnoses among men who have sex with men who attended sexual health clinics , england , 20092014 . \n surveillance codes for extragenital infections were introduced mid-2011 and are only available for chlamydia and gonorrhea diagnoses . in 2014 , the median age for msm in whom these stis were diagnosed ranged from 28 years ( genital warts ) to 36 years ( syphilis ) ( table 2 ) . \n more than three quarters of msm in whom stis were diagnosed were white , 60.3%71.4% were born in the united kingdom , and 12.6%18.4% were born in other european countries ( table 2 ) . \n msm in whom bacterial stis were diagnosed were more likely to be hiv positive and live in london than were msm in whom genital warts and herpes were diagnosed ( table 2 ) . * genitourinary medicine ( gum ) and integrated gum / sexual and reproductive health clinics . \n we report the continuing increase of diagnoses of all stis among msm , particularly for syphilis , for which the largest number of cases was recorded since 1994 . \n similar levels of syphilis diagnoses among men ( reporting for msm began in 1994 ) were last reported in the late 1970s and were followed by a precipitous decline after the emergence of hiv in the united kingdom in the 1980s ( 5 ) . in 2014 , \n most msm in whom stis were diagnosed lived in london , and an average of 16% were born in europe outside the united kingdom . given such a mobile population , the potential for spread of these infections to msm in other major cities is clear ( 6 ) . \n diagnoses of stis among hiv - positive msm since 2009 have steadily increased ; the sti rate is 24 times that among msm who are hiv negative or of unknown hiv status ( 7 ) . \n sex without condom use , associated with increasing hiv seroadaptive behaviors ( i.e. , seeking out partners according to their hiv serostatus for unprotected sex ) and use of geospatial social networking applications , may facilitate sti transmission in concentrated sexual networks ( 8,9 ) . given the risk for emergence of strains of neisseria gonorrhoeae that are resistant to first - line antimicrobial drugs ( 1 ) , the increase in gonorrhea diagnoses , especially among msm , is concerning . in response to gonorrhea testing guidance published in 2010 ( 10 ) , \n use of highly sensitive nucleic acid amplification tests for screening of extragenital sites in msm has occurred more frequently ( 11 ) ; this change may account for part of the increase in gonorrhea diagnoses in the earlier part of the decade . \n however , the most recent update contained no changes in syphilis testing guidelines ( 12 ) , so recent increases are unlikely to result from changes in testing practice . \n further , although more msm were tested for stis in 2014 compared with 2013 , the rate of chlamydia and gonorrhea diagnoses remained relatively stable , while that of syphilis increased . \n given the comprehensive coverage of national sti surveillance and that shcs in england are open access and free , most syphilis and gonorrhea cases are probably captured in gumcadv2 ( 13 ) . \n a key limitation of gumcadv2 is that it does not collect any behavioral data ; however , an enhancement to collect data on behavior , including recreational drug use and unprotected anal intercourse , is being piloted ( https://www.gov.uk/guidance/genitourinary-medicine-clinic-activity-dataset-gumcadv3-pilot ) . a focus on biomedical interventions , such as preexposure prophylaxis , for the control of hiv among msm may have unintended consequences for transmission of other stis , which highlights a need to ensure that robust sti prevention and control measures are in place ( 14 ) . \n these measures should include promoting condom use ; increased screening ( in the united kingdom , quarterly hiv / sti testing of msm who engage in condomless sex with new partners is recommended ) ; ensuring that services are easily accessible ; and promoting other risk reduction strategies to improve the health and well - being of msm ( 15 ) . \n ", "role": "user" }, { "content": "surveillance data from sexual health clinics indicate recent increases in sexually transmitted infections , particularly among men who have sex with men . \n the largest annual increase in syphilis diagnoses in a decade was reported in 2014 . \n less condom use may be the primary reason for these increases .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: rheumatoid arthritis ( ra ) is an autoimmune rheumatic disease with unknown etiology that occurs in approximately 1% of population worldwide . \n the majority of rheumatologists believe that early onset of therapy ( within three months ) must change the course of ra . \n arthrofoon ( affine - cleared ultra - low doses of antibodies to human tnf- : a mix of homeopathic dilutions c12 , c30 and c200 ) is a disease - modifying antirheumatic drug ( dmard ) aproved by the russian ministry of health for the treatment of ra in 2001 . \n it modifies production / activity of endogenous tnf-. animal studies showed that arthrofoon induced a systemic anti - inflammatory response and exerted an analgesic effect . in collagen - induced arthritis in rats , arthrofoon influenced systemic proinflammatory cytokine production , reducing interleukin ( il)-1 , il-6 and tnf- serum concentration . \n our study enrolled 114 outpatients ( aged 20 - 73 years ) with early ra . \n we investigated the efficacy and safety of nsaids ( diclofenac 100 mg / day compared with nimesulide 200 mg / day for the first month or longer at the request ) and dmards ( methotrexate 7.5 - 15 mg / week per os compared with arthrofoon under the tongue in an initial dose of 8 tablets / day with a maintenance dose of 3 - 4 tablets / day at condition improvement or combination of two last drugs in the same doses for two years ) . \n the treatment of one of the outpatients with arthrofoon as a newer drug for basic therapy is analyzed here . \n a 28-year - old russian woman with initial diagnosis of reactive arthritis ( rea ) was enrolled in a clinical study for early arthritis at the chair of polyclinic therapy of the orenburg state medical academy ( russian federation ) . \n patient complained of the pain and swelling of hands , wrists , elbows , knees , ankles and foot , as well as morning stiffness for 30 minutes with no history of fever . \n all symptoms started two weeks ago . before the advent of joint complaints , she had history of chicken pox and conjunctivitis . \n the disease activity score 28 ( das28 ) was 4.97 points ( moderate activity ) . \n the results of serum c - reactive protein ( crp ) testing were positive ( two points on three - point scale ) . \n the undifferentiated arthritis was taken into consideration and patient was treated with oral nimesulide ( nise of dr . \n reddy 's laboratories ltd , [ hyderabad ] , india ) 100 mg twice a day to reduce inflammation . during differentiation of diagnosis with reactive arthritis immunosorbent assay of blood , the antibodies ( \n immunoglobulins g ) directed to mycoplasma hominis and ureaplasma urealyticum were found in titers 32 and 41 units , respectively . \n no atypical agents were found by method of polymerase chain reaction after scraping the surface of the cervix . \n search of ra markers by method of enzyme - linked immunosorbent assay of blood established rising of antibodies against modified citrullinated vimentin ( titer 28.55 u / ml ) and normal level of igm - rf ( 3.6 u / ml ) . the x - rays of patient 's hands showed no bone lesions . \n ultrasonography of radiocarpal and second through fourth metacarpophalangeal ( mcp ) joints detected tenosinovitis of the extensor carpi ulnaris , synovitis and periarthritis of the mcp joints of the hands , and symmetric erosions of the second mcp joints ( total score of erosions = five ) ; a minor synovitis and periarthritis of knee joints . \n after two weeks , the secondary diagnosis was established , namely : probable ra , seronegative , very early stage , activity ii , erosive ( radiological changes were not revealed ) , functional class i. the dynamics of pain vas , patient 's and physician 's global assessments of disease activity are shown in figure 1 . \n treatment has been continued by arthrofoon from eight tablets daily ( two tablets , four times a day ) to three tablets daily ( one tablet , three times a day ) after five days . \n dynamics of some clinical parameters during the two - year treatment with arthrofoon ( vas 0 - 100 mm ) : ptga patient 's global assessment of disease activity ; pnga physician 's global assessment of disease activity ; pain vas pain score on visual analog scale after one month , the moderate response to the treatment according to european league against rheumatism ( eular ) criteria and according to american college of rheumatology ( acr ) , 20% improvement ( acr20 ) response rates were found . \n ultrasonic signs of tenosinovitis of the radiocarpal joints and synovitis of mcp joints were not visualized and other inflammatory changes decreased [ figure 2 ] . \n erosions of second mcp joints of both hands are identified ( arrow ) after 24 months , the das28 decreased to 2.34 points that corresponded to remission according to eular criteria and 50% improvement has been noted according to acr criteria . \n , the patient received three two - week courses of the treatment with nimesulide only . \n radiological signs of periarticular osteoporosis were found after two years and they confirmed the diagnosis of ra . \n the young age of the patient and the recent conjunctivitis became the reasons for diagnosis of ra by rheumatologist . \n the probability of a trigger role of an atypical infection ( mycoplasma and/or ureaplasma ) as well as the originator of chicken pox in the development of autoimmune disorders in patient has not been excluded . according to new 2010 acr / eular classification criteria for ra , patient had score of 6/10 ( > 10 involved joints with at least one small joint = five , abnormal crp = one ) . \n although duration of symptoms was less than six weeks at first visit , this score evaluation after the exclusion of rea could be evidence of early ra and basis for initiating disease - modifying therapy . \n a short history of the disease allowed recommending of low - dose inhibitor of tnf-. the treatment with arthrofoon for two years demonstrated sustained improvements in disease activity , ultrasonic findings and reduction in the requirement for nsaids . \n early prescription of ultra - low doses of tnf- antibodies arthrofoon for two years led to clinical improvement and delay of radiological disease progression in patient with probable ra of moderate activity initially .", "role": "user" }, { "content": "the main aim of treatment of early rheumatoid arthritis ( ra ) should be to achieve clinical remission to prevent structural damage and physical disability . \n arthrofoon modifies production / activity of endogenous inhibitors of tumor necrosis factor- ( tnf- ) . \n the sublingual rout is the most acceptable to ambulatory treatment because it does not produce the adverse reactions associated with intravenous therapy . \n the treatment with arthrofoon in outpatient with early ra is analyzed here . \n this report is devoted to the 28-year - old russian woman who received arthrofoon due to suspicion of early ra . \n the strategy of early prescription of ultra - low doses of tnf- antibody within two years was confirmed by the clinical improvement and delay of radiological disease progression in patient with undifferentiated arthritis or probable ra initially .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: pulmonary arterial hypertension ( pah ) is associated with the impairment of the nitric oxide ( no)-soluble guanylate cyclase ( sgc)-cyclic guanosine monophosphate ( cgmp ) pathway , supporting a role for therapeutic interventions which target this pathway . \n\n until recently , \n the only practical therapeutic strategy to enhance the no sgc cgmp pathway was the use of phosphodiesterase-5 ( pde-5 ) inhibitors , such as sildenafil , tadalafil , and vardenal to slow cgmp degradation . \n the clinical benefits associated with the pde-5 inhibitor have led to interest in testing whether other agents that modulate no signaling might be similarly beneficial in pah . \n this is important considering the finding that up to 60% of patients with pah do not respond to therapy with the pde-5 inhibitor sildenafil , with some indication that pulmonary cgmp production is markedly impaired . \n stimulators of scg are novel pharmacological agents that directly stimulate sgc , both independently of no and in synergy with no \n . ongoing research on sgc stimulators led to the development of the more potent and more specific sgc stimulator , riociguat . \n recently , the us food and drug administration has approved riociguat to treat pah in adults . \n support for approval of riociguat comes from the recently published patent-1 ( pulmonary arterial hypertension soluble guanylate cyclase stimulator trial 1 ) study . \n sgc is a dimeric , heme - containing , redox - sensitive enzyme that catalyzes the synthesis of the second messenger cgmp , which produces ( through a number of downstream mechanisms ) numerous biological effects , including vasorelaxation and inhibition of fibrosis , smooth muscle proliferation , apoptosis , leukocyte recruitment , and platelet aggregation . \n no binds to sgc only when the heme group on sgc is in the reduced ferrous state . \n notably , binding of no to the reduced heme group leads to an approximately 200-fold increase in the conversion of gtp to cgmp . \n alternatively , oxidation of this heme group results in its dissociation from the enzyme and the generation of no - insensitive sgc . \n\n in the presence of an intact heme - moiety , \n however in pah , although the total sgc expression is increased , alteration of the redox state of sgc through oxidative stress may lead to reduced levels of the no - sensitive form of sgc . \n sgc agonists are divided in two different categories according to their mechanism of action \n : ( 1)sgc stimulators sensitize sgc to no by stabilizing the binding site on sgc . \n accordingly , action of sgc stimulators is dependent on the presence of a reduced heme ( heme - dependent compounds such as riociguat)(2)sgc activators preferentially and effectively activate sgc when it is in an oxidized ( heme - independent compounds such as cinaciguat ) \n sgc stimulators sensitize sgc to no by stabilizing the binding site on sgc . \n accordingly , action of sgc stimulators is dependent on the presence of a reduced heme ( heme - dependent compounds such as riociguat ) sgc activators preferentially and effectively activate sgc when it is in an oxidized ( heme - independent compounds such as cinaciguat ) riociguat is the first drug approved in the new class of sgc stimulators . \n riociguat acts through a dual mechanism : ( 1 ) direct stimulation of sgc in a no independent fashion , and ( 2 ) by sensitization of sgc to low endogenous no levels . \n in experimental studies , riociguat stimulated recombinant sgc up to 73-fold , and in the presence of a no - releasing agent , increased the activity of sgc 112-fold above baseline . \n pre - clinical studies with sgc stimulators have shown vasodilatory , antiproliferative , antifibrotic , and antiinflammatory effects . \n patent-1 \n is a double - blind , randomized , placebo - controlled trial of 443 patients with pah at 124 centers in 30 countries . \n patients were randomly assigned in 2:4:1 ratio to ; placebo , riociguat in individually adjusted doses up to 2.5 mg three times daily ( 2.5 mg maximum group ) , or riociguat in individually adjusted doses that were capped at 1.5 mg three times daily ( 1.5 mg maximum group ) . \n the 1.5-mg maximum group was included for exploratory purposes ( to provide information about lower riociguat doses ) , and the data from that group were not included in the efficacy analyses . \n the primary endpoint was change from baseline to the end of week 12 in the 6-minute walk distance ( 6mwd ) . \n secondary endpoints included pulmonary vascular resistance changes , n - terminal prohormone brain - type natriuretic peptide ( nt - probnp ) , who functional class , time to clinical worsening , borg scores , euroqol 5-dimensional classification component scores , and living with pulmonary hypertension scores . at week 12 , 6mwd had increased from baseline by a mean of 30 m in the 2.5 mg maximum group and had decreased by a mean of 6 m in the placebo group ( least - squares mean difference , 36 m ; 95% confidence interval : 20 to 52 ; p < 0.001 ) . \n significant benefits were seen in the 2.5 mg maximum group , as compared with the placebo group , with respect to a range of secondary end points including pulmonary vascular resistance ( p < 0.001 ) , nt - probnp ( p < 0.001 ) , who functional class ( p = 0.003 ) , time to clinical worsening ( p = 0.005 ) , and score on the borg dyspnea scale ( p = 0.002 ) . \n notably , patients who were receiving endothelin - receptor antagonists or non - intravenous prostanoids were permitted into the study and , accordingly , half of patients were on background therapy for pah : 44% with endothelin - receptor antagonists and 6% with nonintravenous prostanoids . \n pre - specified subgroup analysis showed that riociguat improved the 6mwd in patients who had not received other pah - targeted therapies and also in those who had been on endothelin - receptor antagonists or prostanoids . concerning the safety profile , \n riociguat was well tolerated with a discontinuation rate of 3% in the 2.5 mg maximum group versus 7% in the placebo group . \n syncope occurred less frequently in the 2.5-mg maximum ( 1% ) compared to placebo ( 4% ) . \n the 2.5 mg maximum group had increased rates of hypotension ( 10% ) and anemia ( 8% ) compared to placebo group ( 2% for each ) , though without statistical significance . \n both pde-5 inhibitors and sgs stimulants target the no - sgc - cgmp pathway . from a mechanistic point of view \n , sgc stimulators may have several advantages over pde-5 inhibitors : the therapeutic action of pde-5 inhibitors is dependent on baseline no availability ( which is typically reduced in pah ) . \n in contrast , owing to its no - independent mode of action , sgc stimulators are effective even when no production is markedly reduced.pde-5 inhibitors acts by prevention of cgmp degradation ; accordingly in diseases where cgmp levels are low ( as in pah ) , the effectiveness of pde-5 inhibitors is expected to be markedly limited . \n furthermore , when pde-5 is inhibited , the activity of other pdes may compensate for it.in pah , sgc is upregulated in small pulmonary arteries \n ( as a compensatory mechanism ) with increased opportunity for enhanced therapeutic actions of sgc stimulants . \n the therapeutic action of pde-5 inhibitors is dependent on baseline no availability ( which is typically reduced in pah ) . \n in contrast , owing to its no - independent mode of action , sgc stimulators are effective even when no production is markedly reduced . \n pde-5 inhibitors acts by prevention of cgmp degradation ; accordingly in diseases where cgmp levels are low ( as in pah ) , the effectiveness of pde-5 inhibitors is expected to be markedly limited . \n furthermore , when pde-5 is inhibited , the activity of other pdes may compensate for it . in pah , \n sgc is upregulated in small pulmonary arteries \n ( as a compensatory mechanism ) with increased opportunity for enhanced therapeutic actions of sgc stimulants . compared with other pah - targeted therapies , \n the position of riociguat within the therapeutic armamentarium in the management of pah depends on several factors including : efficacy , safety , suitability for use in drug combination , drug - drug interaction , number of daily doses , and cost . \n efficacy : in the patent-1 trial , the overall difference in the 6mwd with riociguat as compared with placebo , was 36 m at 12 weeks . \n this change in 6mwd is consistent with the increases observed in previous studies ( 22.4 m ; 95% confidence interval : 17.427.5 m ) . \n in comparison with pde-5 inhibitors , \n this change in 6mwd is less than that observed with sildenafil in the super trial , \n where the mean placebo - corrected treatment on 6mwd was 45 m , 46 m , and 50 m for patients receiving 20 , 40 , and 80 mg of sildenafil , respectively . on the other hand , \n the improvement in 6mwd reported in patent-1 is close to that reported with tadalafil in the phirst trial , where tadalafil in 40 mg was associated with 33 m increase in 6mwd relative to placebo . \n improvement in who functional class in patent-1 is modest where 21% of patients moved to lower class . in super trial , \n the proportions of patients with an improvement of at least one functional class were 7% , 36% , and 42% for patients receiving 20 , 40 , and 80 mg of sildenafil , respectively . \n in the phirst trial , \n no significant differences in the proportions of patients with and without improvement of who functional class were observed with tadalafil compared with placebo . \n importantly , many variables should be considered when comparing changes in 6mwd or who functional class among different studies ( e.g. , population characteristics , baseline 6mwd and who functional class , duration of study , proportion of patients on background therapy ) . for example , in the phirst study , \n about half of patients were receiving bosentan as a background therapy , while in super background therapy was not permitted . \n this is important since the use of background effective therapy may reduce the ability to demonstrate a statistically significant difference in 6mwd or who functional class between the placebo and the active treatment groups . \n two adverse events appear to be common among patients receiving the highest tolerated dose of riociguat : hypotension ( 10% ) and anemia ( 8% ) . \n the risk of hypotension should be minimized by a gradual individual dose titration to the highest tolerated dose ( in patent-1 , riociguat was titrated over 8 weeks ) , and by contraindicating concomitant use with other drugs affecting the no - sgc - cgmp pathway ( e.g. , pde-5 inhibitors , nitrates ) . \n the apparent increased risk of bleeding has been addressed by means of a prominent warning and a description of bleeding events in the adverse reactions section of the product monograph . \n drug - drug interaction : so far , the interaction potential of riociguat with other drugs is virtually unknown . \n recent in vitro study suggests that riociguat is a p - glycoprotein substrate and might therefore act as a victim drug when co - administered with strong p - glycoprotein inducers or inhibitors . \n use in combination therapy : there is a growing trend to combine drugs that target multiple pathologic pathways in an attempt to increase efficacy and optimize outcomes in pah patients . \n in one retrospective analysis , 56% of patients required additional therapy within 2 years . \n half of patients in patent-1 were on background therapy for pah with significant improvement in the 6mwd in pah - drug - therapy - naive patients as well as patients treated with combination therapy . \n patent - plus trial investigated the effects of riociguat on supine systolic blood pressure in patients receiving sildenafil over 12 weeks . in this study , \n riociguat was associated with a high rate of discontinuation due to hypotension with no evidence that this combination exerts a beneficial effect . \n efficacy : in the patent-1 trial , the overall difference in the 6mwd with riociguat as compared with placebo , was 36 m at 12 weeks . \n this change in 6mwd is consistent with the increases observed in previous studies ( 22.4 m ; 95% confidence interval : 17.427.5 m ) . \n in comparison with pde-5 inhibitors , \n this change in 6mwd is less than that observed with sildenafil in the super trial , \n where the mean placebo - corrected treatment on 6mwd was 45 m , 46 m , and 50 m for patients receiving 20 , 40 , and 80 mg of sildenafil , respectively . on the other hand , \n the improvement in 6mwd reported in patent-1 is close to that reported with tadalafil in the phirst trial , where tadalafil in 40 mg was associated with 33 m increase in 6mwd relative to placebo . \n improvement in who functional class in patent-1 is modest where 21% of patients moved to lower class . in super trial , \n the proportions of patients with an improvement of at least one functional class were 7% , 36% , and 42% for patients receiving 20 , 40 , and 80 mg of sildenafil , respectively . \n in the phirst trial , \n no significant differences in the proportions of patients with and without improvement of who functional class were observed with tadalafil compared with placebo . \n importantly , many variables should be considered when comparing changes in 6mwd or who functional class among different studies ( e.g. , population characteristics , baseline 6mwd and who functional class , duration of study , proportion of patients on background therapy ) . \n for example , in the phirst study , \n about half of patients were receiving bosentan as a background therapy , while in super background therapy was not permitted . \n this is important since the use of background effective therapy may reduce the ability to demonstrate a statistically significant difference in 6mwd or who functional class between the placebo and the active treatment groups . \n two adverse events appear to be common among patients receiving the highest tolerated dose of riociguat : hypotension ( 10% ) and anemia ( 8% ) . \n the risk of hypotension should be minimized by a gradual individual dose titration to the highest tolerated dose ( in patent-1 , riociguat was titrated over 8 weeks ) , and by contraindicating concomitant use with other drugs affecting the no - sgc - cgmp pathway ( e.g. , pde-5 inhibitors , nitrates ) . \n the apparent increased risk of bleeding has been addressed by means of a prominent warning and a description of bleeding events in the adverse reactions section of the product monograph . \n drug - drug interaction : so far , the interaction potential of riociguat with other drugs is virtually unknown . \n recent in vitro study suggests that riociguat is a p - glycoprotein substrate and might therefore act as a victim drug when co - administered with strong p - glycoprotein inducers or inhibitors . \n use in combination therapy : there is a growing trend to combine drugs that target multiple pathologic pathways in an attempt to increase efficacy and optimize outcomes in pah patients . \n in one retrospective analysis , 56% of patients required additional therapy within 2 years . \n half of patients in patent-1 were on background therapy for pah with significant improvement in the 6mwd in pah - drug - therapy - naive patients as well as patients treated with combination therapy . \n patent - plus trial investigated the effects of riociguat on supine systolic blood pressure in patients receiving sildenafil over 12 weeks . in this study , \n riociguat was associated with a high rate of discontinuation due to hypotension with no evidence that this combination exerts a beneficial effect . \n\n preserving right ventricular ( rv \n the significant reduction of nt - probnp in pah patients receiving riociguat may denote a favorable effect on rv performance . \n possible mechanisms may include : reduction of rv afterload induced by pulmonary vasodilatation ; reversing remodeling of pulmonary vasculature mediated by antiproliferative and antifibrotic effect ; or direct effect on the rv . \n this possibility is supported by the results of experiments in a mouse model of chronic rv pressure overload , in which riociguat treatment reduced the collagen content of the rv and improved the rv ejection fraction . \n accordingly , long - term open - label extension study for patients who completed patent-1 was performed ( patent-2 ) . \n after 1 year of treatment , 6mwd further improved by 48 m over the original baseline of patent-1 , who functional class also continued to improve and 68% of the overall cohort were in functional class i / ii after 1 year of treatment . in conclusion , \n riociguat , the first drug approved in the new class of sgc stimulators , represents an advance within the available therapeutic armamentarium for pah with an efficacy that is expected to be comparable to pde-5 inhibitors . since combination therapy is gaining more ground in the management strategy of patients with pah , large - scale and long term studies with clinical endpoints should be planned in order to further evaluate the role of the combination between riociguat and other pah - targeted therapies with special emphasis on endothelin receptor antagonists .", "role": "user" }, { "content": "stimulators of soluble guanylate cyclase ( scg ) are novel pharmacological agents that directly stimulate sgc . \n ongoing research on sgc stimulators led to the development of the more potent and more specific sgc stimulator , riociguat.recently , the us food and drug administration has approved riociguat to treat pulmonary arterial hypertension in adults . \n support for the approval of riociguat comes from the recently published patent-1 ( pulmonary arterial hypertension soluble guanylate cyclase stimulator trial 1 ) study .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: contractility of airway smooth muscle ( asm ) depends on the dynamic regulation of intracellular calcium concentration . \n contractile agonists act on g - protein - coupled receptors to cause oscillatory changes in [ ca]i , mediated by influx of calcium from the extracellular space and release of calcium from the intracellular stores [ 25 ] . \n the major [ ca]i store in asm cells is the sarcoplasmic reticulum ( sr ) . \n release of calcium from the sr is brought forth principally by two signaling molecules , inositol 1,4,5-trisphosphate ( ip3 ) and cyclic adp - ribose ( cadpr ) . \n cyclic adp - ribose is derived from -nad through the enzymatic activity of adp - ribosyl cyclase which is a constituent of the cell - surface protein cd38 ( reviewed in ) . \n calcium influx into the cell can occur through voltage- and receptor - operated calcium channels in the plasma membrane [ 7 , 8 ] . \n it can also occur by influx that is triggered by depletion of sr calcium stores through a mechanism known as store - operated calcium entry . \n transient receptor potential proteins are thought to mediate influx of calcium through receptor- and store - operated channels . in asm cells , \n contractile agonists cause a biphasic elevation of [ ca]i that is characterized by an initial rapid rise , followed by a decline to a plateau concentration above the basal level . the initial rapid phase of the biphasic elevation of [ ca]i has been attributed to sr calcium release , while the sustained phase of elevation is to influx from extracellular space . \n however , with the use of improved temporal and spatial resolution features of real - time confocal microscopy , our understanding of agonist elicited [ ca]i elevation has significantly changed . \n these studies have demonstrated that the biphasic elevation of the [ ca]i consists of propagating regenerative calcium oscillations of similar amplitude within a given region of the asm cell . the frequency and the propagation velocity of these calcium oscillations increase with increasing concentration of the agonist . \n the biphasic nature of the [ ca]i response is in fact the spatiotemporal integration of oscillations in calcium across the entire cell . \n while the initiation of the calcium oscillations depends on sr calcium release , their sustenance requires repletion of the sr stores through influx from the extracellular space . \n furthermore , activation of the ip3 receptors in the sr is crucial for the initiation of calcium oscillations by agonists , while maintained calcium oscillations require calcium release through the ryanodine receptor channels in the sr . \n calcium release through the ryanodine receptor channels in the sr in asm cells is mediated by cadpr . \n recent studies have also demonstrated that inflammatory cytokines such as tnf- , il-1 , and ifn- and the th2 cytokine il-13 regulate the expression and function of the pathways that govern [ ca]i responses to agonists , thereby contributing to asm hyperresponsiveness [ 10 , 11 ] . \n one of the pathways in [ ca]i regulation in asm cells involves cd38 , and the expression of cd38 in asm cells derived from asthmatics is upregulated by tnf- to a significantly greater extent than in cells from nonasthmatics . \n the regulation of cd38 expression and the role of different transcription factors , signaling intermediates and micrornas in this regulation , have been the focus of investigations in our laboratory . \n cd38 is a 45-kda type ii glycoprotein expressed in a variety of cells from a diverse array of organisms . \n it belongs to a family of nucleotide metabolizing enzymes capable of generating cyclic adenosine diphosphoribose ( cadpr ) and adpr from -nad or naadp from nadp . \n cadpr , adpr , and naadp have been shown to be involved in intracellular calcium regulation in both immune cells and excitable cells such as smooth muscle cells . \n earlier studies from our laboratory showed evidence for intracellular calcium release by cadpr during activation of gq and gi - type g - protein - coupled receptors in airway smooth muscle cells . \n studies in other types of cells indicate that this calcium release involves the dissociation of fkbp-12.6 and activation of ryanodine receptors in the sarcoplasmic reticulum [ 15 , 16 ] . \n evidence from fkbp-12.6 knockout mice revealed that cadpr may be an endogenous ligand for this protein and binding of cadpr is an essential step in the activation of ryanodine receptor calcium release channels . in airway \n smooth muscle cells as well as cardiac myocytes , the calcium - induced calcium release mechanism may be mediated through activation of ryanodine receptor channels by cadpr . \n the evidence that cadpr is involved in calcium release in airway smooth muscle stems from the following observations : direct addition of cadpr to the cytosolic compartment of airway smooth muscle cells releases calcium from ryanodine receptor channels ; cadpr antagonists inhibit intracellular calcium release brought forth by contractile agonists ; increasing cd38 expression by inflammatory cytokines ( i.e. , tnf- , il-1 , il-13 ) and thereby augmenting cd38/cadpr signaling cause significant enhancement of calcium release by agonists that is sensitive to inhibition by cadpr antagonists . \n these results provide evidence for cd38/cadpr signaling in the regulation of intracellular calcium and its potential for enhanced contribution to such regulation during inflammation in airway smooth muscle . \n investigations from other laboratories show that in chemokine - stimulated neutrophils and dendritic cells , adpr may activate plasma membrane - associated trpm2 calcium channels and thereby regulate neutrophil and dendritic cell chemotaxis . \n evidence from lund 's laboratory has revealed that chemotaxis and bacterial clearance are significantly compromised in neutrophils obtained from cd38 deficient mice . \n furthermore , evidence also demonstrates that in cd38 deficient mice there is significant attenuation of t - cell dependent humoral immune responses following immunization with antigens . \n this defect in humoral immune response appears to result from lack of migration of dendritic cells from inflammatory sites to regional lymph nodes and insufficient dendritic cell priming of cd4 t cells at these sites . \n these results provide evidence for a role of cd38 in both innate and adaptive immune responses of the host . \n in an attempt to elucidate the contribution of this signaling pathway to airway function , we developed two different models systems to evaluate intracellular calcium responses to spasmogens : asm cells obtained from cd38 knockout and wild - type mice ; human asm cells expressing a smooth muscle phenotype and maintained in short - term cultures . \n the intracellular calcium responses to acetylcholine and endothelin-1 of cells obtained from cd38ko mice were significantly lower than responses in cells from wt mice . \n the calcium responses in the myocytes from cd38ko mice were also insensitive to modulation by the cadpr antagonist , indicating that the defect in calcium signaling can be attributed to lack of cadpr generation . \n this defective calcium signaling in airway smooth muscle cells is reflected in significant attenuation of methacholine - induced airway resistance and dynamic compliance measured in intact cd38ko mice , suggesting an airway phenotype of these mice . in hasm cells in culture , \n the intracellular calcium responses to multiple spasmogens were found to be significantly augmented upon treatment with inflammatory cytokines that are implicated in asthma . \n the augmented calcium responses were attributable to increased cd38/cadpr signaling since they were reduced by a cadpr antagonist as well as by antisense downregulation of cd38 expression [ 10 , 23 ] . the fact that inflammatory cytokines such as tnf- and il-13 , a th2 cytokine , are capable of increasing the capacity for cd38/cadpr signaling in human asm cells indicates its potential role in human asthma . \n based on the results reported above in the cd38ko mice and in hasm cells following exposure to inflammatory cytokines , we hypothesized that cd38/cadpr signaling will be enhanced during airway inflammation , thus contributing to airway hyperresponsiveness , a hallmark feature of asthma . in order to address this hypothesis \n specifically , we used two different model systems : ( i ) mouse models of inflammatory airway disease to assess the contribution of cd38 to airway inflammation and ahr ; ( ii ) cd38 expression , function , and its regulation in asm cells obtained from asthmatic and nonasthmatic donors . \n cd38 deficient mice were generated by cockayne et al . to study the role of this molecule in host immune responses against pathogens . \n cd38 mice showed an immunological phenotype characterized by attenuated chemotaxis and antigen presentation by dendritic cells . in our laboratory \n , we evaluated the respiratory phenotype of cd38 mouse following induction of airway inflammation by murine recombinant il-13 or tnf-. the inflammatory cytokine tnf- and the th2 cytokine il-13 play important roles in the development of allergic asthma . in light of the findings by partida - snchez et al . that cd38-null mice show suboptimal inflammatory response , we chose the model of cytokine - induced airway inflammation to circumvent the possibility of reduced inflammatory response to allergen challenge . following brief and repeated exposure to il-13 or tnf- , \n comparable airway inflammation was induced in wild type and cd38 mice [ 24 , 25 ] . \n however , the airway resistance in response to the contractile agonist methacholine was significantly attenuated in the cd38 mice compared to the wild type mice [ 24 , 25 ] . in light of our findings that cd38 deficient mouse airway myocytes show reduced ca responses , we hypothesized that the differential methacholine responsiveness of cd38 mice can be attributed to the altered asm contractility . \n tracheal rings isolated from the wt and cd38 were used for measurement of isometric contractile responses following exposure to il-13 or tnf- in vitro . \n cd38-deficient tracheal rings generated significantly reduced isometric force in response to agonist compared to the tracheal rings from wt mice [ 24 , 25 ] . \n these observations support our hypothesis that cd38 contributes to the development of airway hyperresponsiveness ( ahr ) through its pivotal role in asm ca dynamics and contractility . based on the findings reported by lund and her coworkers , the immunological functions of cd38 in the development of ahr can not be understated . \n studies by lund showed that cd38 expression in immune cells is critical for the inflammatory and immunological steps that culminate in allergy and ahr ( reviewed in ) . \n the critical events in host immune response to allergens , such as antigen presentation by dendritic cells , were negatively impacted in cd38-deficient mice . \n studies using ovalbumin - induced allergic inflammation in mouse revealed that along with attenuated methacholine responsiveness , cd38-deficient mice also developed reduced airway inflammation , signified by substantially reduced eosinophilia , th2 cytokines , and allergen - specific immunoglobulins e ( ige ) and g1 ( igg1 ) levels compared to the wt mice . \n these findings support a pivotal role for cd38 in the pathogenesis of asthma through its dual functions in the immune response to allergen and asm contractility . \n the involvement of cd38/cadpr signaling pathway in the pathogenesis of asthma at multiple levels of the process is supported by these observations . \n the intracellular calcium responses to contractile agonists , isometric contractile responses of tracheal rings , and responsiveness of airways to inhaled methacholine are significantly attenuated in airway smooth muscle obtained from cd38 mice . in hasm cells exposed to inflammatory cytokines , the cd38/cadpr signaling pathway contributes to enhanced calcium signaling in response to activation of g - protein - coupled receptors . \n the airway hyperresponsiveness following cytokine challenge or allergen sensitization and challenge is significantly compromised in cd38 mice . \n these observations led us to speculate that asm cells derived from asthmatic donors will have increased basal and cytokine - induced expression of cd38 . to address this hypothesis \n cells were exposed to tnf- or vehicle following growth arrest and cd38 expression , and their enzymatic activities were measured . \n there was very little , if any , basal expression of cd38 in cells from either asthmatic or nonasthmatic donors . \n however , exposure to a range of tnf- concentrations caused a significantly greater induction of cd38 expression in asm cells from asthmatics than in cells from nonasthmatics . \n this differential induction of cd38 expression occurred as early as 6 hrs following exposure to tnf- and maintained for over 24 hrs and was unrelated to level of tnfr1 expression in the cells ( figure 1 ) . \n this pattern of differential induction of cd38 expression was seen in cells obtained from donors with a history of clinical asthma as well as from fatal asthmatics . \n this asthmatic phenotype in terms of differential cd38 induction was maintained for up to 5 passages in culture . \n we examined some potential mechanisms involved in the differential induction of cd38 expression and for the asthmatic phenotype of asm cells . \n our previous studies showed that members of the map kinases and the transcription factors nf-b and ap-1 were required for tnf- induction of cd38 expression in hasm cells . \n therefore , we hypothesized that the increased cd38 expression will be reflected by greater activation of map kinases and the transcription factors nf-b and ap-1 . \n it is worth noting that the cd38 promoter has response elements for these transcription factors and mutagenesis of either of these transcription factor binding sites would result in lack of promoter activation by tnf- . in hasm cells derived from asthmatic donors \n , we found consistently elevated p38 and erk activation ( phosphorylated forms ) , but not that of jnk as compared to cells from nonasthmatic donors ( figure 1 ) . \n activation of nf-b and ap-1 was measured by analyzing their nuclear content as well as their binding to consensus sequences . \n these results support the concept that asthmatic asm cells are intrinsically programmed to express greater levels of map kinase activation and the greater induction of cd38 expression by tnf- may involve increased rate of transcription rather than transcript stability . this conclusion is further supported by the fact that transcript stability was comparable in cells from asthmatics and nonasthmatics . however , we can not rule out the contribution of other transcription factors to the observed differential response of asthmatic asm cells . furthermore , signaling mechanisms independent of map kinases may also be involved in this differential induction . \n it should be noted that significant erk and p38 phosphorylation were reported in both epithelial cells and smooth muscle cells obtained from severe asthmatics , suggesting that these map kinase pathways may have an important role in the pathogenesis of severe asthma [ 3133 ] . \n the levels of expression of kinases upstream of erk as well as the map kinase phosphatase-1 are comparable in cells from asthmatics and nonasthmatics . \n precisely how a higher level of activation of these map kinases is maintained in the asthmatic asm cells is not entirely clear . \n with respect to other signaling pathways involved in the regulation of cd38 and their potential contribution to the asthmatic phenotype , we explored the role of pi3 kinases in such regulation . \n we found that asm cells from both asthmatics and nonasthmatics express comparable levels of class i pi3 kinase p110 isoforms , , and . \n inhibition of the and isoforms by sirna transfection causes comparable magnitude of inhibition of tnf--induced cd38 expression in cells from asthmatics and nonasthmatics . however , under comparable levels of sirna - mediated downregulation of expression , the residual cd38 expression in asthmatic asm cells was significantly higher than expression in cells from nonasthmatics . \n these results , while demonstrating similar expression levels of class i pi3 kinase isoforms in asthmatic and nonasthmatic asm cells , show decreased sensitivity of cd38 expression in asthmatic asm cells to inhibition of pi3 kinases . this is yet another example of an asthmatic phenotype of airway smooth muscle cells in terms of differential contribution of signaling pathways to the regulation of expression of specific genes . in this context \n , studies have shown that pi3 kinase signaling contributes to the proliferative response of asm cells from asthmatics , while the erk map kinase pathway seems to be involved in cells from nonasthmatic donors . \n posttranscriptional regulation of genes is a mechanism aimed at altering the target gene expression swiftly in response to an environmental cue . in light of recent advancements in understanding microrna regulation of gene expression \n , it appears that posttranscriptional regulation is also a fine tuning mechanism to delicately balance gene expression in cells ( reviewed in ) . \n studies in our laboratory have shown that cd38 expression is regulated posttranscriptionally , at the level of transcript stability . \n map kinases p38 and erk1/2 regulate cd38 expression by modulating the transcript stability . the exact mechanism involved in the regulation of cd38 mrna stability is not known . however , our studies focused on both rna - binding proteins and microrna as the potential mechanisms involved in the post - transcriptional regulation of cd38 . specific short sequence motifs , primarily located on the 3 untranslated region ( 3utr ) , interact with rna - binding proteins to modulate the stability or translatability of the transcript [ 36 , 37 ] . \n adenylate - uridine- ( au- ) rich motifs and cytosine - guanosine - uridine- ( cgu- ) rich motifs are the major sequence motifs found in 3utr of many transcripts and act as the cis elements responsible for mediating mrna stability [ 38 , 39 ] . \n the cd38 3utr possesses 4 au - rich motifs , indicating a potential role for these cis elements in the post - transcriptional regulation of cd38 expression . in vitro \n pull down assays , using synthetic rna oligonucleotide containing one of the au - rich elements of cd38 3utr and hasm cell lysates , showed that the rna - stabilizing protein , human protein r ( hur ) , the translational modulator protein and t - cells intracellular antigen-1 ( tia-1 ) bind selectively to the au - rich element , in the presence of tnf-. however , transient over expression of hur in the hasm cells did not result in altered cd38 mrna expression , suggesting rna destabilizing proteins , such as tristetraprolin ( ttp ) , may have a counteracting role in tnf--induced cd38 expression in hasm cells ( unpublished results ) . \n micrornas ( mirna ) are emerging as molecules with important roles in gene regulation in different orders of living organisms . \n encoded from intronic or intergenic regions of the genome , mirnas regulate the expression of a significant portion of human genes . \n the general mechanism of regulation by mirna is through modulating the stability or translatability of the target mrna . on average , \n a single mirna can target and regulate ~100 different genes , although it is suggested that the cluster of genes regulated by a single mirna would belong to a particular cellular function . \n systematic studies on the expression and role of some of these mirnas have been carried out in our laboratory . \n luciferase - cd38 3utr reporter assays confirmed that mir-140 - 3p , one of the mirnas predicted to target cd38 , functionally targets cd38 3utr . \n further studies using over expression of mir-140 - 3p mimic in hasm cells showed that cd38 mrna and protein expressions were significantly downregulated by mir-140 - 3p . \n findings of our study suggest that the inhibitory effect of mir-140 - 3p mimic on cd38 expression is only partially mediated through direct binding to the cd38 3utr , since there was only a marginal inhibition of luciferase activity by mir-140 - 3p mimic . \n the dominant effect of mir-140 - 3p on cd38 expression appears to be mediated indirectly through transcriptional mechanisms , by inhibiting activation of p38 map kinase and nf-b . \n microrna target prediction algorithms revealed an array of genes potentially targeted by mir-140 - 3p in humans ( table 1 ) . \n we also found that mir-140 - 3p expression was significantly attenuated by tnf- exposure in asthmatic hasm cells compared to nonasthmatic hasm cells . \n whether the greater degree of downregulation of mir-140 - 3p in asthmatic asm cells compared to asm cells from nonasthmatics contributes to the reported differential induction of cd38 expression in these cells is not clear , but remains an attractive hypothesis . \n these findings also suggest that cd38 and mir-140 - 3p may be part of a differential gene expression profile in asthmatic hasm cells , indicating a potential role for these two molecules in the pathogenesis of asthma . \n recent investigations have provided insights into the role of micrornas in the regulation of asm cell phenotype and asm contractility [ 41 , 42 ] . \n studies have also reported altered microrna expression profiles in various cells obtained from asthmatic donors [ 43 , 44 ] . \n the roles of specific micrornas in the development of ahr have also been demonstrated by studies in mouse models of asthma [ 4547 ] . \n microrna target prediction algorithms revealed an array of genes potentially targeted by mir-140 - 3p in humans ( table 1 ) . \n the table has a partial list of the genes that encode proteins associated with g - protein - coupled receptor function , ion channels , chemokines , transcription factors , signaling proteins , contractile and cytoskeletal elements , and cell proliferation . \n it should be noted that some of the genes targeted by the microrna are involved in the regulation of cd38 expression , that is , transcription factors , map kinases , and pkc signaling - associated proteins . \n downregulation of expression of the chemokines by mir-140 - 3p has the potential to have significant anti - inflammatory effects . \n our investigations of cd38 expression have revealed some important differences between asm cells from asthmatics and nonasthmatics in the sensitivity to inflammatory cytokines in terms of level of expression , sensitivity of expression to inhibition of signaling intermediates such as map kinases and pi3 kinases , in microrna expression , and post - transcriptional regulation of expression . \n these differences in the asthmatic asm cells are maintained over at least 5 passages in culture . \n studies in cytokine or allergen - induced inflammatory airway disease mouse models have revealed that cd38 contributes to airway hyperresponsiveness both through its role in generating calcium - mobilizing second messenger molecules and thereby the contractility of airway smooth muscle and through its role in adaptive immune response . \n we propose that increased capacity for cd38/cadpr signaling in airway smooth muscle in asthma contributes to the development of airway hyperresponsiveness . \n whether the differences that we report transcend all asthma phenotypes is not currently known and requires further investigation .", "role": "user" }, { "content": "cd38 is a transmembrane glycoprotein expressed in airway smooth muscle cells . \n the enzymatic activity of cd38 generates cyclic adp - ribose from -nad . \n cyclic adp - ribose mobilizes intracellular calcium during activation of airway smooth muscle cells by g - protein - coupled receptors through activation of ryanodine receptor channels in the sarcoplasmic reticulum . \n inflammatory cytokines that are implicated in asthma upregulate cd38 expression and increase the calcium responses to contractile agonists in airway smooth muscle cells . \n the augmented intracellular calcium responses following cytokine exposure of airway smooth muscle cells are inhibited by an antagonist of cyclic adp - ribose . \n airway smooth muscle cells from cd38 knockout mice exhibit attenuated intracellular calcium responses to agonists , and these mice have reduced airway response to inhaled methacholine . \n cd38 also contributes to airway hyperresponsiveness as shown in mouse models of allergen or cytokine - induced inflammatory airway disease . in airway \n smooth muscle cells obtained from asthmatics , the cytokine - induced cd38 expression is significantly enhanced compared to expression in cells from nonasthmatics . \n this differential induction of cd38 expression in asthmatic airway smooth muscle cells stems from increased activation of map kinases and transcription through nf-b , and altered post - transcriptional regulation through micrornas . \n we propose that increased capacity for cd38 signaling in airway smooth muscle in asthma contributes to airway hyperresponsiveness .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: carotid artery stenting has become an established alternative to endarterectomy in the management of patients with significant carotid artery disease , , , . despite remarkable improvements in technology , techniques , and ancillary medical therapy , complications and adverse events \n in particular , in - stent carotid restenosis , while relatively uncommon , remains a challenging condition , , . to date , a number of treatments for carotid in - stent restenosis have been proposed , with heterogeneous outcomes . \n the most favorable data , in terms of safety and efficacy , have been reported for drug - eluting balloons , , , , , , , . \n however , it remains unclear how to address recurrent restenosis despite prior drug - eluting balloon dilation . \n we hereby report the clinical vignette of a patient with recurrent carotid in - stent restenosis despite prior use of a drug - eluting balloon with a coronary bioresorbable vascular scaffold . \n this case may expand the armamentarium of endovascular specialists focusing on carotid artery disease , while providing further proof of the safety and efficacy of current bioresorbable vascular scaffolds . \n a 59-year - old woman was admitted for evidence at duplex ultrasound scan of significant in - stent restenosis in the right common and internal carotid artery . \n two years before , a carotid duplex ultrasound scan had been performed for the work - up of a transient ischemic attack , disclosing a significant stenosis of the ostium of the right internal carotid artery . \n she was then referred to another institution for carotid angiography , which confirmed the significant carotid stenosis , and underwent during the same procedure carotid angioplasty with implantation of an unspecified 7.0 40 mm open - cell self - expanding stent . \n less than 6 months later , control duplex ultrasound scan disclosed severe in - stent restenosis , albeit without any symptom . \n after diagnostic angiography with a 6 french jr4 diagnostic catheter ( vistabrite , cordis , miami , fl , usa ) highlighting diffuse in - stent restenosis involving both the common and internal carotid artery , a 7 french jr4 guiding catheter was placed in the proximal right common carotid artery via a 0.035 260 cm amplatz super stiff j - tip emerald guidewire ( cordis ) ( fig . \n 1 ) . then , we deployed an 7.0 mm angioguard rx filter ( cordis ) , and proceeded to predilation with a 3.0 20 mm trek balloon ( abbott vascular , santa clara , ca , usa ) , followed by a 5.0 40 mm aviator plus balloon ( cordis ) . \n despite the apparently satisfactory angiographic result , we then opted for further postdilation with a 5.0 80 mm legflow paclitaxel - eluting balloon ( cardionovum , bonn , germany ) in order to minimize the risk of recurrent hyperplasia , achieving a good final angiographic result . \n periprocedural antithrombotic therapy included aspirin , clopidogrel , tirofiban and unfractioned heparin , whereas discharge antiplatelet therapy consisted of lifelong aspirin and clopidogrel for 6 months . \n a control duplex ultrasound scan was performed 6 months later . despite the lack of symptoms , \n subocclusive recurrent restenosis was found , involving both the carotid bifurcation and the proximal internal carotid artery . \n as previously , after diagnostic angiography confirming the recurrent in - stent restenosis , we deployed a 7 french jr4 guiding catheter and a 7.0 angioguard rx filter ( fig . \n predilation was then performed with a 4.0 40 mm ryujin plus balloon ( terumo , tokyo , japan ) . \n given the drug - eluting balloon failure , the promising data accrued so far for coronary bioresorbable vascular scaffolds even in complex lesions , and our favorable preliminary experience with extra - coronary applications of these devices , , we chose to implant a 3.5 28 mm absorb bioresorbable vascular scaffold ( abbott vascular ) in the distal common carotid artery and proximal internal carotid artery , placing the distal edge of the device well beyond the distal edge of the stent . \n this choice was mainly based on our goal of minimizing the risk of subsequent edge restenosis . \n we then postdilated the bioresorbable vascular scaffold and the rest of the original stent with a 4.5 30 mm aviator plus balloon , achieving a satisfactory final angiographic result . \n periprocedural antithrombotic therapy included aspirin , clopidogrel , tirofiban and unfractioned heparin , whereas discharge antiplatelet therapy was based on lifelong aspirin and clopidogrel for 12 months . \n the patient remained asymptomatic after discharge , and control duplex ultrasound scan was performed 6 and 13 months later ( fig . \n 3 ) , without any evidence of restenosis . specifically , after more than 12 months since the implantation of the bioresorbable vascular scaffold for recurrent in - stent restenosis and drug - eluting balloon failure , the metallic stent appeared largely patent , with faint signs of still incompletely resorbed scaffold struts , all devoid of significant restenosis ( peak systolic velocity 120 cm / s , end - diastolic velocity 40 cm / s ) ( fig . \n thanks to the pioneering efforts of many endovascular specialists from different disciplines , the introduction of key pieces of technology such as embolic protection devices and dedicated carotid stents , and landmark clinical trials , carotid artery stenting is now an established alternative to surgical endarterectomy in patients with significant carotid artery disease , , . \n much attention has been paid to the risk of post - procedural or long - term stroke after stenting , but restenosis is also a clinically relevant complication . \n while carotid in - stent restenosis is relatively uncommon , it may pose technical challenges , especially when diffuse or subocclusive , and often recurs after repeat balloon dilation . \n accordingly , a number of approaches and devices have been proposed , including endarterectomy , cutting balloons , scoring balloons , endovascular atherectomy , drug - eluting balloons , and drug - eluting stents . \n no single one appears clearly best , as neointimal hyperplasia can often recur unless the stent is altogether removed surgically , a procedure which is also fraught with significant morbidity , , , , , , , , , , , , , . \n bioresorbable vascular scaffolds have been recently devised and introduced into clinical practice for the treatment of coronary artery disease , . \n the most commonly used one is the absorb device , which elutes everolimus , thus equaling a drug - eluting stent in terms of hyperplasia inhibition , while relying on a fully resorbable poly - l - lactic acid ( plla ) platform and polymer . \n this balloon expandable device has proven non - inferior to second - generation drug - eluting stents , and has also been used successfully even in very complex coronary lesions , such as bifurcations , chronic total occlusions , and long lesions , , , . \n we have recently accrued a substantial expertise in using bioresorbable vascular scaffolds in both coronary and non - coronary lesions , including a preliminary experience with infra - inguinal implantation of these devices for superficial femoral artery disease or proximal popliteal artery disease , . \n building upon such premises , we chose to implant a bioresorbable vascular scaffold to treat a recurrent carotid in - stent restenosis and drug - eluting balloon failure . \n our acute and long - term results are quite novel , being unprecedented in the literature , and appear quite favorable . \n moreover , they support the concept of considering the individualized off - label use of coronary bioresorbable vascular scaffolds for selected non - coronary lesions . \n more importantly , this clinical vignette highlights the remarkable effectiveness , versatility and safety of this technology , which clearly merits further development , with the hope of eventually developing bioresorbable vascular scaffolds explicitly designed for non - coronary lesions , . \n in addition , its low profile ensures easy deliverability from any access site , . despite such rationale and the favorable outcome of our patient \n , we do not advocate yet a widespread application of bioresorbable vascular scaffolds for the management of carotid in - stent restenosis . \n first , the bioresorbable vascular scaffold is more fragile than a metallic stent and may lead to a higher risk of embolization in comparison to a drug - eluting balloon , especially when forcefully post - dilated . \n while this risk remains limited during the procedure if embolic protection is adopted , embolization of relatively large strut fragments ( 150 m ) may occur before the device is fully endothelialized . \n second , the balloon expandable design may be a distinct disadvantage in the carotid artery , where compression and crushing of the scaffold may occur . \n the presence of an external self - expandable stent may yet provide a certain amount of protection from this complication . \n our 13-month follow - up based on duplex ultrasound scan , while adequate for most clinical purposes , can not disclose or foresee complications or adverse events due to occur much later ( e.g. , 2 or 3 years after the procedure ) and may have lower sensitivity than repeat angiography . \n nonetheless , this is unlikely , as after such period of time the scaffold will typically have already lost most of its radial support and drug - eluting properties , and will typically be completely endothelialized . finally , whether invasive imaging may be required whenever bioresorbable vascular scaffolds are used remains open to debate . \n while awaiting for external validation , this clinical vignette may expand the armamentarium of endovascular specialists focusing on carotid artery disease , while providing further proof of the safety and efficacy of current bioresorbable vascular scaffolds . \n \n \n \n written informed consent was obtained from the patient for publication of this case report , as part of our routine consent for anonymized data collection for scientific purposes . \n drs . giordano and biondi - zoccai are responsible for study concept and design , and data collection . \n together with all other authors , they also participated to data analysis and interpretation , writing the paper , and approving its final version . \n ", "role": "user" }, { "content": "highlightsthe management of carotid in - stent restenosis remains challenging , with several potential management strategies available , but none clearly best.bioresorbable vascular scaffolds have proved safe and effective in patients with coronary artery disease , but their use for carotid in - stent restenosis is unprecedented , yet promising.bioresorbable vascular scaffolds could become a useful adjunct to the armamentarium of endovascular specialists , including those managing patients with carotid in - stent restenosis , especially if further refinements in sizes and designs are achieved .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: resolution of inflammation typically follows an ordered series of events orchestrated by different cell types . during the early stages of inflammation , leukocytes such as polymorphonuclear neutrophils ( pmn ) are the first immune cells to arrive at the site of inflammation . \n pmn are recruited by gradients of proinflammatory signals and usually reach peak numbers within 2448 hrs . \n pmn have short half - lives and are normally cleared from sites of inflammation by undergoing apoptosis . \n mobilized monocyte - derived macrophages extravasate to inflammatory tissue sites and clear apoptotic pmn in a nonphlogistic fashion by the process of efferocytosis . \n apoptotic pmn release find - me signals that are sensed by extravasated macrophages . following phagocytosis , apoptotic pmn provides resolution cues to macrophages by evoking distinct signaling events that block release of proinflammatory mediators thus allowing further engulfment of apoptotic cells . \n fleming and mosser note that mobilized macrophages are divided into three groups based upon their activation states [ 4 , 5 ] . \n these include the m1 , m2 , and the recently described regulatory macrophages ( mres ) . \n m1 macrophages , classically referred to as activated macrophages , secrete proinflammatory factors that mediate host defense against invading pathogens . \n m2 macrophages , termed alternatively activated macrophages , are considered to be anti - inflammatory [ 6 , 7 ] . finally \n , mres macrophages secrete considerable amounts of anti - inflammatory cytokines that prevent inflammatory and autoimmune pathology [ 8 , 9 ] . \n mres macrophages also secrete various lipid mediators that play critical roles in resolution of inflammation ( see below ) . \n extensive new research has identified expression markers or phenotypic signatures for the various macrophage activation states in mice . \n they include gene expression changes in il-1 , tnf , and inos for classical activation and arginase-1 ( arg1 ) , chitinase 3-like 3 ( ym-1 ) , and tgf for the alternatively activated macrophages . \n resolution of inflammation and restoration of normal tissue function prevent the development of complications of excessive inflammation , a process referred to as catabasis . \n catabasis is driven by synthesis and release of proresolution lipid mediators such as resolvins , protectins , and lipoxins . \n lipoxins and protectins are synthesized by lipoxygenase enzymes ( such as 15-lipoxygenase ( 15-lox ) ) . \n resolvins are derived from omega-3 polyunsaturated fatty acids such as docosahexaenoic acid and eicosapentaenoic acid . \n russell and schwarze have reviewed the proresolution effects of proresolution mediators in a variety of inflammatory states . \n however their regulation by vitamin c ( vitc , ascorbic acid , asca ) has yet to be examined . \n vitc readily functions as one or two electron - reducing agents for many oxidants and serves as a primary chemical antioxidant in most cell types . \n it modulates complex biochemical pathways that form an essential part of normal metabolism of immune cells . \n , vitc accumulates in millimolar quantities in immune cells such as pmn and macrophages in which intracellular vitc concentrations are typically 4060 fold higher than that present in circulation [ 17 , 18 ] . in pmn , vissers and wilkie showed that intracellular vitc levels regulate neutrophil apoptosis . \n further , vitc contributes to the antioxidant defenses as well as normal pmn and macrophage function . \n oberritter and colleagues showed that intracellular concentrations of vitc in macrophages are in the low millimolar range in freshly prepared peritoneal macrophages and in vivo or in vitro activation of peritoneal macrophages results in a significant decline in their vitc content . \n moreover , mice deficient in vitc generate excessive proinflammatory responses upon infection with the virulent bacterium klebsiella pneumonia . in humans , vitc levels \n are significantly reduced in critically ill patients and specifically in patients with poorly resolving proinflammatory states ( e.g. , sepsis , systemic inflammatory response syndrome ) [ 23 , 24 ] . \n several studies performed in septic patients have found that plasma vitc levels correlate inversely with the incidence of organ failure and directly with survival [ 25 , 26 ] . \n we recently showed that vitc attenuates inflammation and normalizes pmn function in septic mice [ 27 , 28 ] . \n we further showed that parenteral vitc attenuates proinflammatory biomarkers and reduces mortality in human sepsis . \n however information is limited regarding the mechanism by which vitc regulates the progression and eventual resolution of inflammatory states . in the current study we examined the progression and resolution of inflammation using a murine thioglycollate ( tg-)elicited peritonitis model in vitc sufficient and deficient mice . \n while humans lack l - gulono--lactone oxidase ( gulo ) , the final enzyme in the biosynthesis pathway of vitc , mice express functional gulo , resulting in cells and tissues generally maintaining high levels of vitc thereby complicating the translatability of vitc studies in mice , to humans . in order to establish the studies more relevant to humans , \n our studies reveal that progression and resolution of tg - induced inflammation is significantly delayed in vitc deficient mice . \n in particular , the spatiotemporal profile of pro- and anti - inflammatory mediator production by tg - elicited macrophages was significantly different between the vitc sufficient and deficient mice . \n further , macrophage function and phenotype , as well as the antioxidant capacity of vitc deficient macrophages , was significantly impaired by the decline in intracellular vitc levels . \n infusion of parenteral vitc as ascorbic acid ( asca ) partly restored macrophage phenotype and function in vitc deficient mice . \n gulo mice were bred in - house from an established homozygous colony as previously described . in order to maintain their plasma vitc levels similar to that observed in humans , vitc sufficient mice were fed ad libitum with regular chow and water supplemented with vitamin c ( 0.33 \n g / l ) for 1 week , followed by complete removal of dietary vitc for additional 2 weeks . \n we and others have shown that this reduced supplementation significantly decreases the concentration of vitc in immune cells , plasma , and organs [ 27 , 31 , 32 ] . \n injection of 1 ml aged , sterile 3% tg solution to 911-week old gulo mice . \n injection of vitc as asca ( 200 mg / kg in saline ) for a further 3 or 5 days . \n mice were euthanized on day 3 or day 5 , and the peritoneal cavity lavaged with 7 ml of hanks ' balanced salt solution ( hbss ) containing 1% bovine serum albumin ( bsa ) . \n the lavage was centrifuged and the resulting leukocyte pellet was washed with hbss and resuspended in rpmi-1640 medium . \n cytochemical staining of peritoneal cells was performed using harleco hemacolor solution ( emd millipore ) . \n pmns were then separated from macrophages by adherence to a plastic dish as described previously [ 28 , 33 ] . \n peritoneal macrophages were plated at a density of 2 10 cells in 35 mm dishes in growth media ( dmem , 10% fbs ) . \n human acute monocytic leukemia suspension cell line ( thp-1 ) was obtained from atcc ( manassas , va ) . \n thp-1 cells were maintained in rpmi-1640 medium containing 10% fbs according to the instructions supplied . \n for induction of macrophages , pma ( 100 nm ) was added to the medium and cells were seeded at a density of 0.1 10 cells / cm into tissue culture dishes and maintained in a humidified atmosphere of 95% air and 5% co2 . \n media containing pma were replaced every 2 days , and experiments started after 5 days in culture , when the cells were phenotypically macrophage . \n plasma and intracellular vitc levels of peritoneal macrophages seeded onto 35 mm dishes were measured using a fluorescence end - point assay adopted from vislisel et al . . \n briefly , 0.2 ml of cold 20% trichloroacetic acid ( tca ) and 0.2 ml of cold 0.2% dithiothreitol ( dtt ) were added to 0.1 ml of plasma , vortexed for 2 min , and centrifuged ( 10,000 g , 10 min , 4c ) . \n peritoneal macrophages were similarly extracted with tca and dtt and frozen at 70c for batch analysis . \n assay buffer containing 1 m sodium acetate , ph 5.5 , and 1 mm tempol was added to each well and the plate was incubated for 10 minutes at room temperature . \n freshly prepared o - phenylenediamine ( opda ) solution ( 5.5 mm opda in acetate buffer of ph 5.5 ) was then added . after a further 30 min incubation in the dark , \n fluorescence was measured at an emission wavelength of 425 nm following excitation at 345 nm and values determined after comparison to a standard curve . \n intracellular asca levels were estimated spectrophotometrically from the standard curve and the intracellular concentrations derived from the measured amount of asca and the known macrophage cell volume . \n isolation of total rna and real - time qpcr analyses were performed as described previously . \n briefly total rna was extracted and purified using qiashredders and rneasy columns according to the manufacturer 's specifications ( qiagen ) . \n total rna ( 1 g ) was reverse - transcribed into cdna using the high capacity cdna reverse transcription kit . \n complimentary dna ( cdna ) was diluted ( 1 : 500 ) and real time qpcr performed using power sybr green qpcr master mix . primers were designed to anneal to sequences on separate exons or to span two exons . \n cycling parameters were 95c , 10 min , 40 cycles of 95c , 15 sec , and 60c , 1 min . \n all pcr assays were performed in triplicate . no template controls and no reverse transcriptase controls were included . the mrna expression in macrophages from a \n the mrna expression of all other samples was compared relative to this sample which was used as the baseline . \n 18s rrna was used as housekeeping gene against which all the samples were normalized for differences in the amount of total rna added to each cdna reaction and for variation in the reverse transcriptase efficiency among the different cdna reactions . \n automated gene expression analysis was performed using the comparative quantitation module of mxpro qpcr software ( agilent ) . \n mouse macrophage and thp - i whole - cell extracts were isolated for western blot analysis as described previously . \n proteins were resolved by sds polyacrylamide gel electrophoresis ( 420% ) and electrophoretically transferred to polyvinylidene fluoride membranes ( 0.2 m pore size ) . \n immunodetection was performed using chemiluminescent detection with the renaissance western blot chemiluminescence reagent plus ( perkin elmer life sciences inc . , \n blots were stripped using the restore western blot stripping buffer ( pierce biotechnology inc . , \n purified rabbit polyclonal antibodies to phospho - nfb p65 ( ser276 , cell signaling ) , nfb p65 ( sc-109 , santa cruz biotechnology ) , inos ( sc-650 , santa cruz biotechnology ) , and actin ( sc-1616 , santa cruz biotechnology ) were used . optical densities of antibody - specific bands were determined using quantity one acquisition and analysis software ( bio - rad , hercules , ca ) . \n mouse peritoneal lavage obtained on day 3 and day 5 from vitc sufficient or deficient mice following induction of tg - induced peritonitis was pelleted by centrifugation at 4c . \n cells were resuspended in facs buffer containing fc receptor block ( cd16/cd32 ebioscience ) for 10 min at 4c . \n aliquots of the suspension were incubated at 4c for 30 min ( in the dark ) with fluorescein isothiocyanate ( fitc-)conjugated anti - mouse cd45 ( ebioscience ) and allophycocyanin ( apc-)conjugated anti - mouse cd11b ( ebioscience ) . \n all runs were performed on a bd accuri c6 flow cytometer ( bd accuri cytometers , mi , usa ) and analyzed using flowjo software ( tree star , ashland , or ) . \n fluorescence microscopy for evaluation of mitochondrial reactive oxygen species ( ros ) in macrophages was performed using the cell - permeant probe mitotracker red cmxros as described by the manufacturer . \n briefly , macrophages from vitc sufficient or deficient mice were grown on ibidi 6-channel ibitreat -slide vi . \n following treatments ( h2o2 , 18 hours ) culture media were aspirated and cells were fixed in 3.7% paraformaldehyde in pbs for 10 minutes at 4c . \n fluorescence imaging was performed using an olympus model ix70 inverted phase microscope ( olympus america , melville , ny ) outfitted with an ix - fla fluorescence observation system equipped with a tritc filter cube ( 530560 nm excitation and 590650 nm emission , chroma technology corp . \n fluorescence images were digitized and captured by a magnafire digital camera ( optronics , goleta , ca ) . \n quantitative analysis of eicosanoids was performed as previously described by us with minor modifications [ 3843 ] . \n briefly , peritoneal lavage was clarified by centrifugation and 0.05% bht and 10 ng of each internal standard added . \n the internal standards used were ( d4 ) 8-iso pgf2 , ( d11 ) 5-iso pgf2-vi , ( d4 ) 6k pgf1 , ( d4 ) pgf2 , ( d4 ) pge2 , ( d4 ) pgd2 , ( d4 ) ltb4 , ( d5 ) lipoxin a4 , ( d5 ) resolvin d2 , ( d4 ) txb2 , ( d4 ) ltc4 , ( d5 ) ltd4 , ( d5 ) lte4 , ( d8 ) 5-hydroxyeicosatetranoic acid ( 5hete ) , ( d8 ) 15-hydroxyeicosatetranoic acid ( 15hete ) , ( d8 ) 14,15 epoxyeicosatrienoic acid , ( d8 ) arachidonic acid , and ( d5 ) eicosapentaenoic acid . \n the samples were mixed by vortexing and subjected to purification via solid phase extraction ( spe ) using a 24 port vacuum manifold ( sigma - aldrich ) . \n strata - x spe columns ( phenomenex ) were washed with methanol ( 2 ml ) and then dh2o ( 2 ml ) . \n the samples were applied to the column . thereafter the sample vials were rinsed with 5% meoh ( 2 ml ) , which was then used to wash the columns . \n the eluents were then dried under vacuum and reconstituted in lcms grade 50 : 50 etoh : dh2o ( 100 l ) for eicosanoid quantitation via uplc esi - ms / ms analysis . \n a 14-minute reversed - phase lc method utilizing a kinetex c18 column ( 100 2.1 mm , 1.7 m ) and a shimadzu uplc was used to separate the eicosanoids at a flow rate of 500 l / min at 50c . \n the column was first equilibrated with 100% solvent a ( acetonitrile : water : formic acid ( 20 : 80 : 0.02 , v / v / v ) ) for two minutes and then 10 l of sample was injected . \n solvent b ( acetonitrile : isopropanol ( 20 : 80 , v / v ) ) was increased in a linear gradient to 25% solvent b to 3 minutes , to 30% by 6 minutes , to 55% by 6.1 minutes , to 70% by 10 minutes , and to 100% by 10.1 minutes . \n 100% solvent b was held until 13 minutes and then was decreased to 0% by 13.1 minutes and held at 0% until 14 minutes . \n the eluting eicosanoids were analyzed using a hybrid triple quadrapole linear ion trap mass analyzer ( absciex 6500 qtrap ) via multiple - reaction monitoring in negative - ion mode . \n the mass spectrometer parameters used were curtain gas : 30 ; cad : high ; ion spray voltage : 3500 v ; temperature : 300c ; gas 1 : 40 ; and gas 2 : 60 ; declustering potential , collision energy , and cell exit potential were optimized per transition . \n statistical analysis was performed using sas 9.3 and graphpad prism 6.0 ( graphpad software , san diego , ca , usa ) . \n in order to make the gulo mice vitc deficient , supplementation of water with asca was withdrawn as described in the methods section . within 3 weeks of removal of vitc supplementation , \n this decline was not associated with deleterious changes in weight or health status in the vitc deficient mice ( data not shown ) . to determine whether vitc deficiency impacts the progression of peritoneal inflammation , vitc sufficient or deficient mice were injected with tg and the progression of inflammation was monitored on days 3 and 5 ( as described in section 2 ) . \n with asca ( 200 mg / kg ) prior to harvest of peritoneal lavage ( see section 2 ) . \n administration of ascorbate for 3 days restored circulating plasma vitc concentrations in these mice to levels observed in the vitc sufficient mice ( figure 1 ) . in all 3 groups , \n the infiltration of inflammatory cells on day 1 was similar to that observed in wild type mice and was in agreement with our previous observations ( table 2 ) . \n as seen in table 2 , there was also no difference in the total number of cells elicited from the peritoneal exudation of day 3 and day 5 . \n however , significant differences in the cellular composition of the lavage were evident on day 3 and day 5 between the 3 groups . in the vitc sufficient mice group , \n mononuclear cells were the predominant cell type on days 3 and 5 ( table 2 ) . \n pmn numbers , which peaked on day 1 , returned to baseline by days 3 and 5 . \n in contrast , significantly elevated numbers of pmns persisted in the peritoneal exudates of vitc deficient mice on days 3 and 5 ( table 2 ) . \n infusion of asca reduced pmn numbers by day 3 with a significant decline in pmn numbers to baseline similar to the vitc sufficient mice by day 5 table 2 . we previously observed that tg - elicited pmn from vitc deficient mice ( on day 1 ) demonstrated increased expression of the proinflammatory genes tnf and il-1 . \n here we examined the expression of multiple pro- and anti - inflammatory mediators originating from macrophages , the predominant cell type recruited to the inflamed peritoneum on days 3 and 5 . \n as seen in figure 2 , significant differences were evident in the magnitude of pro- and anti - inflammatory mediator expression on days 3 and 5 . on day 3 , \n increased expression of the proinflammatory mediators ( il-1 , tnf , and mcp-1 ) was observed in macrophages from vitc deficient mice when compared to macrophages from vitc sufficient mice ( figure 2(a ) , ( a ) , ( c ) , and ( e ) ) . \n infusion of asca in the vitc deficient mice ( figure 2(a ) , ( a ) , ( c ) , and ( e ) ) . \n in contrast , anti - inflammatory gene expression ( ym1 and arg1 , but not il-10 ) was elevated in macrophages from vitc sufficient mice ( figure 2(a ) , ( b ) , ( d ) , and ( f ) ) . \n daily asca infusion induced ym1 expression in vitc deficient macrophages but failed to restore arg1 expression . \n il-10 expression on the other hand was significantly lowered by asca infusion on day 3 ( figure 2(a ) , ( b ) , ( d ) , and ( f ) ) . on day 5 ( figure 2(b ) ) , proinflammatory gene expression remained persistently elevated in macrophages from vitc deficient mice ( il-1 and mcp-1 ) but was attenuated by asca infusion . in contrast , anti - inflammatory gene expression in vitc deficient macrophages was significantly higher when compared to macrophages from vitc sufficient mice ( arg1 , il-10 ) . \n asca infusion did not alter anti - inflammatory gene expression on day 5 although arg1 levels were now similar to that observed in vitc sufficient mice ( figure 2(b ) , ( b ) , ( d ) , and ( f ) ) . canali et al . \n recently showed that in contrast with baseline physiological activation , exposure to a second hit such as an inflammatory stimulus results in a markedly different modulation of gene expression in human peripheral blood mononuclear cells in the presence or absence of vitc supplementation . to examine whether peritoneal macrophages would exhibit an altered modulation of gene expression , we exposed day 3 peritoneal macrophages from vitc sufficient and deficient mice to bacterial lipopolysaccharide ( lps , 50 ng / ml ) . \n some macrophages were incubated with asca ( 3 mm , 16 hours ) prior to lps exposure . \n as seen in figures 3(a ) and 3(b ) , lps exposure resulted in a robust increase in expression of proinflammatory markers ( il-1 , tnf ) in macrophages from vitc sufficient mice . \n proinflammatory gene expression was also induced in macrophages from vitc deficient mice , but the magnitude of induction was significantly greater than that observed in the vitc sufficient macrophages ( figures 3(a ) and 3(b ) ) . \n importantly , exposure of vitc deficient macrophages to asca prior to lps significantly attenuated il-1 and tnf expression . \n increased nfb activation ( figure 3(c ) ) and inos protein expression ( figure 3(d ) ) was observed upon exposure of vitc deficient macrophages to lps ( p < 0.05 ) . \n macrophages undergo reprogramming to adopt a variety of functional phenotypes upon receiving differentiation cues from their surrounding environment . \n we examined whether macrophage vitc sufficiency or deficiency could influence macrophage function during resolution of acute inflammation . \n macrophages were isolated on day 3 following tg - mediated peritonitis from vitc sufficient or deficient mice and intracellular concentrations of vitc measured ( as described in section 2 ) . \n asca ( 200 mg / kg ) prior to harvest of peritoneal lavage ( see section 2 ) . as seen in figure 4(a ) , \n in contrast , intracellular ascorbate levels were significantly depleted in macrophages from vitc deficient mice . \n administration of asca for 3 days also restored macrophage intracellular concentrations to levels observed in the vitc sufficient mice ( figure 4(a ) ) . \n their expression is associated with generation of proresolving lipid mediators and successful resolution of inflammation . \n therefore we examined gal-1 and 15-lox expression in day 3 and day 5 macrophages from vitc sufficient or deficient mice . \n as seen in figure 4(b ) , gal-1 and 15-lox expression was significantly induced in macrophages from vitc sufficient mice on day 3 when compared to macrophages from vitc deficient mice . \n asca infusion restored gal-1 expression in vitc deficient macrophages but did not affect 15-lox expression on day 3 ( figure 4(b ) ) . \n in contrast , gal-1 expression in vitc deficient macrophages was delayed and observed to be higher on day 5 following tg - induced peritonitis ( figure 4(c ) ) . \n 15-lox expression was induced by asca infusion on day 5 and was higher than that observed in macrophages from vitc sufficient or deficient mice . in agreement \n with the expression data seen above , resolvin ( figure 4(d ) ) production was higher on day 5 in vitc deficient mice indicating delayed resolution of inflammation . \n . recently showed that gal-1 was selectively expressed in cd11b macrophages , and its expression declined significantly once these cells converted toward a cd11b phenotype . \n moreover , cd11b macrophages are the predominant subtype to depart the peritoneum . to determine whether vitc regulated reprogramming of peritoneal macrophages to proresolution cd11b phenotype we used flow cytometry to examine the distribution of cd11b and cd11b population on macrophages isolated on day 3 and day 5 following tg - induced peritonitis in vitc sufficient or deficient mice . as seen in figure 5 , there was a significant transition from cd11b to a cd11b phenotype observed from day 3 to day 5 in the vitc sufficient macrophages . \n this was not evident in the macrophages from vitc deficient mice indicative of a delay in the resolution of tg - induced peritonitis in these mice . \n release of large amounts of ros during activation exposes macrophages themselves to oxidant stresses not encountered by most other cell types . to test whether vitc deficiency affected mitochondrial function in macrophages , we exposed peritoneal macrophages ( day 3 ) from vitc sufficient or deficient mice to varying concentrations of h2o2 for 18 hours and stained the cells with mitotracker red cmxros as described in section 2 . \n this probe is selectively retained by mitochondria , where it is oxidized to its fluorescent form . \n as seen in figures 6(a ) and 6(e ) , control macrophages from vitc sufficient or deficient mice were stained brightly with the probe . \n oxidative stress from exposure to h2o2 decreased fluorescent staining in macrophages from both vitc sufficient and vitc deficient mice . \n however , the magnitude of decrease was significantly greater in macrophages from vitc deficient mice ( figures 6(f)6(h ) ) . \n this decrease was partially reversed by pretreatment of vitc deficient macrophages with asca ( figures 6(j ) and 6(k ) ) . \n these studies indicate that vitc deficient macrophages sustain greater mitochondrial dysfunction when challenged with ros . to address whether the modulatory activities of vitc are effective in human monocyte / macrophages , we exposed thp-1 cells to bacterial lps and examined the mrna expression of the proinflammatory genes il-6 , il-8 , and tnf. since the culture medium in which thp-1 cells are grown contains no vitc , we increased intracellular concentrations of vitc by loading cells with asca prior exposure to lps . \n as seen in figure 7(a ) , exposure of thp-1 cells to lps resulted in a robust activation of mrna for il-6 , il-8 , and tnf. loading cells with asca did not affect baseline proinflammatory gene expression \n . however lps exposure of asca loaded cells resulted in significant attenuation of mrna expression of these proinflammatory genes . \n attenuation of mrna expression was likely achieved by reduction in activation of the transcription factor nfb following lps exposure ( figure 7(b ) ) . \n in this study , we examined the mechanism by which vitc regulates the resolution of sterile inflammation . using mice lacking the ability to synthesize vitc , we show that subnormal cellular vitc levels negatively impact the progression and resolution of sterile inflammation . \n in particular , our results demonstrate that low circulating vitc levels are associated with significant delays in the timing of resolution of inflammation . \n this apparent vitc - dependent process primarily occurs due to failure of macrophages to transition from a proinflammatory to a proresolving phenotype . \n the initial response to sterile inflammation was identical in vitc sufficientanddeficient mice . during the early proinflammatory phase no differences in the cell numbers or cell types \n however , by days 3 and 5 , vitc deficient mice exhibited significant numbers of pmn in peritoneal exudates ( table 2 ) . \n spatiotemporal mrna profiling of macrophage - derived inflammatory mediators revealed dramatic differences in the magnitude of pro- and anti - inflammatory mediator gene expression ( figure 2 ) . \n macrophages from vitc sufficient mice displayed prominent anti - inflammatory phenotypes , while vitc deficient macrophages persistently expressed mrna for il-1 , tnf , and mcp-1 , findings characteristic of a proinflammatory phenotype . \n lps activation of day 3 macrophages from vitc deficient mice led to proinflammatory gene expression that was significantly greater in magnitude than that observed in vitc loaded macrophages ( figure 3 ) . \n lps stimulation was characterized by enhanced nfb activation and inos induction in vitc deficient macrophages ( figure 3 ) . \n importantly , on day 3 , vitc sufficient macrophages demonstrated cues for reprogramming into resolution type macrophages , a vital step required for resolution of inflammation . in day 3 \n macrophages from vitc sufficient mice , expression of gal-1 and 15-lox mrna was robust ( figure 4 ) . in contradistinction , enhanced gal-1 and 15-lox mrna expression was delayed to day 5 in vitc deficient macrophages . \n the delays in resolution we observed in vitc deficient mice were confirmed by quantification of resolvins in peritoneal exudates ; increases of which were present only on day 5 ( figure 4 ) . \n further confirmation of altered spatiotemporal relationships was achieved by studying macrophage phenotypic changes by examining the distribution of cd11b on macrophages from vitc sufficient or deficient mice on day 3 and day 5 following tg - induced peritonitis ( figure 5 ) . \n phenotypic changes in macrophages were accompanied by alterations in macrophage function as demonstrated by the increased susceptibility of vitc deficient macrophages to mitochondrial dysfunction when exposed to reactive oxygen species ( figure 6 ) . in final studies , we employed the human monocyte / macrophage cell line thp-1 , which lacks vitc in culture medium when cultured under standard conditions . \n we demonstrated increased proinflammatory gene expression in thp-1 when exposed to lps under vitc - deprived conditions . \n loading thp-1 cells with asca significantly attenuated mrna expression of proinflammatory genes via a mechanism likely involving reduced activation of the transcription factor nfb . \n vitc loading was effective both in vitro and in vivo since daily asca infusion following induction of peritonitis significantly restored macrophage phenotype and function in the vitc deficient mice . \n ganguly et al . initially reported that vitc deficiency affected migration of guinea pig macrophages under in vitro conditions . \n they later showed that ascorbate deficient peritoneal macrophages were more susceptible to h2o2-induced mitochondrial dysfunction and apoptosis . \n however no studies to date have examined macrophage function during resolution of inflammation in mice lacking the ability to synthesize their own vitc . \n our observation of persistence of pmn at the site of inflammation in vitc deficient mice is in agreement with our previous results and those of vissers and wilkie who used a similar tg model of peritonitis to show impairment in pmn apoptosis and clearance . \n it has been suggested that the engulfment of apoptotic cells is generally anti - inflammatory or immunologically silent due to the fact that it sequesters dying cells thus preventing release of potentially toxic cell contents into the local environment . \n based on the observations that pmn persists for up to 5 days in the peritoneum of vitc deficient mice ( table 2 ) , it is therefore possible that the apoptosis - resistant pmn can cause strong proinflammatory responses from the macrophages that extravasate to sites of inflammation . \n indeed strong and persistent proinflammatory responses were evident in vitc deficient macrophages elicited on day 3 and even day 5 ( figure 2 ) . \n efferocytosis , a process by which dead and/or dying cells are being engulfed and removed by other cells , has been reported to induce production of anti - inflammatory mediators from macrophages that suppress inflammation thereby silently clearing apoptotic cells and thus dampening proinflammatory responses . \n vitc sufficient mice exhibited anti - inflammatory mediator expression in macrophages early ( day 3 ) in the post tg - induced inflammatory process , a phenomenon indicative of functional efferocytosis . \n in contrast , vitc deficient macrophages failed to upregulate anti - inflammatory mediator production until day 5 ( figure 2 ) . \n have shown that gal-1 promotes the generation of m2-like macrophages , which then favors tissue repair during early resolution of inflammation . \n ariel and timor demonstrated that gal-1 promotes generation of mres from m2 macrophages , which generates proresolving lipid mediators . \n this phenotype change promotes macrophage departure from peritoneal cavities with resolving inflammation , thus allowing return of tissue to homeostasis . \n moreover , gal-1 expression , which is enhanced in cd11b macrophages , declines sharply as cells revert to the cd11b phenotype . \n cd11b macrophage phenotypes , as noted previously , promote departure from peritoneal cavities with resolving inflammation . \n our findings ( figures 4 and 5 ) which agree with the above studies implicate vitc as a critical regulator of macrophage transition during resolution of inflammation . \n expression and function of 12/15-lox produce key mediators ( e.g. , lipoxins , resolvins , protectins , and maresins ) that promote resolution of proinflammatory pathologies . \n in particular , human and murine monocytes / macrophages expression of 15-lox is upregulated by efferocytosis with production of mediators such as rvd1 , a mediator shown to promote the resolution of murine peritonitis [ 47 , 57 ] . \n further , gal-1 directly promotes 15-lipoxygenase expression and activity in macrophages during the inflammatory and resolving phases of peritonitis . \n the earlier increases in gal-1 and 15-lox mrna expression in vitc sufficient macrophages ( figures 4(b ) and 4(c ) ) and the delayed resolvin production in the vitc deficient macrophages ( figure 4(d ) ) indicate for the first time that vitc influences multiple processes leading to the resolution of inflammation . \n the findings in this mouse model have significant human relevance since vitc levels are subnormal in multiple human inflammatory disease states including sepsis , systemic inflammatory response syndrome ( sirs ) , trauma , and cancer , among others . in a recently completed phase i trial ( clinicaltrials.gov identifier nct01434121 ) of intravenous asca in critically ill patients with severe sepsis \n , we showed that septic patients exhibited abnormally low vitc plasma levels and that intravenous asca infusion could significantly increase circulating vitc levels . \n further , asca infusion significantly reduced the proinflammatory biomarkers c - reactive protein and procalcitonin as well as multiple organ dysfunction . \n our findings here add a previously unrecognized element to our understanding of the machinery that governs the resolution of inflammation .", "role": "user" }, { "content": "introduction . \n macrophage reprogramming is vital for resolution of acute inflammation . \n parenteral vitamin c ( vitc ) attenuates proinflammatory states in murine and human sepsis . \n however information about the mechanism by which vitc regulates resolution of inflammation is limited . \n methods . to examine \n whether physiological levels of vitc modulate resolution of inflammation , we used transgenic mice lacking l - gulono--lactone oxidase . \n vitc sufficient / deficient mice were subjected to a thioglycollate - elicited peritonitis model of sterile inflammation . some vitc deficient mice received daily parenteral vitc ( 200 mg / kg ) for 3 or 5 days following thioglycollate infusion . \n peritoneal macrophages harvested on day 3 or day 5 were examined for intracellular vitc levels , pro- and anti - inflammatory protein and lipid mediators , mitochondrial function , and response to lipopolysaccharide ( lps ) . \n the thp-1 cell line was used to determine the modulatory activities of vitc in activated human macrophages . \n results . \n vitc deficiency significantly delayed resolution of inflammation and generated an exaggerated proinflammatory response to in vitro lps stimulation . \n vitc sufficiency and in vivo vitc supplementation restored macrophage phenotype and function in vitc deficient mice . \n vitc loading of thp-1 macrophages attenuated lps - induced proinflammatory responses . \n conclusion . \n vitc sufficiency favorably modulates macrophage function . in vivo or in vitro vitc supplementation restores macrophage phenotype and function leading to timely resolution of inflammation .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: the cerebral abscess is a common central nervous system infection that can result from trauma , hematogenous spread , or spread from an adjacent infection such as otitis media or sinusitis . despite exhaustive searches , \n 15 to 30% of abscesses are termed cryptogenic when no source of infection is identified20 ) . a distant infection focus that can cause brain abscesses \n is a cardiac right to left shunt , which is related to patent foramen ovale15 ) , cyanotic cardiac disease15 ) or pulmonary arteriovenous malformation or fistula ( avf ) . \n pulmonary avf is a rare congenital vascular malformation involving direct communication between the pulmonary artery and vein without an intervening capillary bed . \n approximately 8095% of pulmonary avfs are associated with hereditary hemorrhagic telangiectasia ( hht ) , known as osler - weber - rendu syndrome5,8,9 ) . \n the clinical triads of pulmonary avf is cyanosis , exertional dyspnea , and digital clubbing ; however , 56% of one large series were asymptomatic8 ) . \n the most prominent central nervous system ( cns ) complications associated with pulmonary avfs are neurologic events , including transient ischemic attacks31 ) , recurrent stroke1,6,18,27 ) , brain abscesses , and seizures26 ) . \n . we will focus on the cryptogenic brain abscess as developed by patients with idiopathic pulmonary avf , which may be detected only if we consider it may cause the brain abscess . \n a 65-year - old woman was admitted with a 1-month history of headache and cognitive impairment that had become aggravated 10 days prior . \n she showed impairment in orientation and judgment , but there were no lateralization signs of motor paralysis or cranial nerve deficits . \n there was no history of diabetes mellitus , hypertension , lung disease or heart disease . \n her blood pressure was 110/70 mmhg , pulse rate was 74/min , body temperature was 36.5c , and her respiration rate was 20 breaths / min . \n erythrocyte sedimentation rate was 54 mm / h and c - reactive protein ( crp ) was 0.22 mg / l . \n arterial blood gas analysis revealed a ph of 7.425 , pco2 of 42.5 mmhg , po2 of 90.4 mmhg , and an hco3 of 22.2 mmol / l on room air . \n total cholesterol was 249 mg / dl and ldl - cholesterol was 172 mg / dl . \n brain computed tomography ( ct ) showed a mass with perilesional edema on the right frontal lobe . \n brain magnetic resonance ( mr ) imaging revealed a 43-cm ring enhanced mass in the right frontal lobe , which was associated with severe edema and midline shifting to the left side ( fig . \n a chest x ray showed nodular infiltrations on the right mid - lung zone and the left upper and lower lung zones . \n 2 ) and antibiotics were maintained for 8 weeks . her past history gave no indication of exertional dyspnea or episodes of hemoptysis , melena , hematemesis , epistaxis or hematuria that might suggest underlying hht . \n a 45-year - old woman presented with a 7-day history of a progressive left hemiparesis . \n on admission , blood tests showed a hb of 13.4 g / dl , an hct of 39.6% , a white blood cell ( wbc ) count of 6290 cells/l , and a crp elevated to 2.62 mg / l . \n diffusion mr imaging showed a diffusion - restricted ovoid mass on the right motor and sensory cortex measuring 1.50.9 cm that was surrounded by diffuse vasogenic perilesional edema ( fig . \n 3 ) . mr imaging and mr spectroscopy revealed an enhancing lesion involving the right motor and sensory cortex and increased lactate / lipid complex , which was compatible with a brain abscess . \n a chest x ray did not suggest underlying lung disease . however , a chest ct revealed a pulmonary avf in the right upper lung ( fig . \n the brain abscess progressed despite treatment with vancomycin and ceftriaxone , so it was removed via craniotomy and the pulmonary avf was embolized . \n a 65-year - old woman was admitted with a 1-month history of headache and cognitive impairment that had become aggravated 10 days prior . \n she showed impairment in orientation and judgment , but there were no lateralization signs of motor paralysis or cranial nerve deficits . \n there was no history of diabetes mellitus , hypertension , lung disease or heart disease . \n her blood pressure was 110/70 mmhg , pulse rate was 74/min , body temperature was 36.5c , and her respiration rate was 20 breaths / min . \n erythrocyte sedimentation rate was 54 mm / h and c - reactive protein ( crp ) was 0.22 mg / l . \n arterial blood gas analysis revealed a ph of 7.425 , pco2 of 42.5 mmhg , po2 of 90.4 mmhg , and an hco3 of 22.2 mmol / l on room air . \n total cholesterol was 249 mg / dl and ldl - cholesterol was 172 mg / dl . \n brain computed tomography ( ct ) showed a mass with perilesional edema on the right frontal lobe . \n brain magnetic resonance ( mr ) imaging revealed a 43-cm ring enhanced mass in the right frontal lobe , which was associated with severe edema and midline shifting to the left side ( fig . \n a chest x ray showed nodular infiltrations on the right mid - lung zone and the left upper and lower lung zones . \n 2 ) and antibiotics were maintained for 8 weeks . her past history gave no indication of exertional dyspnea or episodes of hemoptysis , melena , hematemesis , epistaxis or hematuria that might suggest underlying hht . \n a 45-year - old woman presented with a 7-day history of a progressive left hemiparesis . \n , blood tests showed a hb of 13.4 g / dl , an hct of 39.6% , a white blood cell ( wbc ) count of 6290 cells/l , and a crp elevated to 2.62 mg / l . \n diffusion mr imaging showed a diffusion - restricted ovoid mass on the right motor and sensory cortex measuring 1.50.9 cm that was surrounded by diffuse vasogenic perilesional edema ( fig . \n 3 ) . mr imaging and mr spectroscopy revealed an enhancing lesion involving the right motor and sensory cortex and increased lactate / lipid complex , which was compatible with a brain abscess . \n however , a chest ct revealed a pulmonary avf in the right upper lung ( fig . \n the brain abscess progressed despite treatment with vancomycin and ceftriaxone , so it was removed via craniotomy and the pulmonary avf was embolized . \n cryptogenic brain abscesses can occur due to rare diseases that are not addressed in routine clinical practice . \n congenital cyanotic heart disease3 ) , patent foramen ovale12,15 ) , thoracic infection19 ) or asymptomatic dental infections7 ) are commonly associated with cerebral abscesses . \n idiopathic asymptomatic pulmonary avfs are also a cause of brain abscess , especially recurrent brain abscess ( table 1 ) . \n the incidence of idiopathic pulmonary avf - related cns complications is between 19 and 59 % 11,25,29 ) . \n associated neurological events included migraine , transient ischemic attack , stroke , abscess , and seizure17,26,30 ) . \n the incidence of brain abscess in patients with a pulmonary avf is around 1 to 5%8 ) . \n the most likely mechanism for these neurological events is a paradoxical embolism across the pulmonary avf or across a coexisting cerebral arteriovenous malformation in patients with hht17 ) . \n the pulmonary capillary bed acts as a filter that removes small thrombi and bacteria as they enter the bloodstream , even during daily activities such as oral hygiene . in a pulmonary avf \n , the pulmonary capillary bed is bypassed , providing a direct right to left shunt that depends on the diameter of the feeding artery . as a consequence \n , patients may develop paradoxical emboli that present as a transient ischemic attack , stroke , or brain abscess5 ) . \n the fundamental defect that we found was a right - to - left shunt from the pulmonary artery to the pulmonary vein , and the degree of shunting determines the clinical effects . \n if shunting is minimal , cyanotic symptoms are usually absent . if the right - to - left shunt is greater than 20% of the systemic cardiac output , or if there is reduction of hemoglobin by more than 50 \n g / l , the patient will have obvious cyanosis , clubbing , and polycythemia17 ) . \n the characteristic findings of cyanosis , clubbing and an extra - cardiac murmur do not always accompany pulmonary avf , and diagnosis may be difficult . \n a review of the mayo clinic experience suggested a morbidity of 2633% and mortality of 816% in untreated patients with pulmonary avf26 ) . \n the international guidelines for the management of pulmonary avf in hht recommends that treatments should be applied to all adults with avfs and children with symptomatic pulmonary avfs . \n the decision to treat in asymptomatic children ( no dyspnea , no exercise intolerance , no growth delay , no cyanosis or clubbing , no previous complication ) should be made on a case - by - case basis . \n the selection of pulmonary avfs for embolization is based on feeding artery diameter , generally 3 mm or greater10 ) . a literature review ( table 1 ) \n indicates that idiopathic pulmonary avfs can cause brain abscess in patients as young as 18 years old . based on these reported series \n , 10 of 13 patients did not have pulmonary avf - related symptoms until the brain abscess developed . \n idiopathic pulmonary avfs are more frequently solitary , around 80% , compared with that of hht ( < 40%)30 ) . \n it means idiopathic pulmonary avfs are less likely to be associated with large right - to - left shunt , this might in part explain why patients with idiopathic pavms might have a lower frequency of cyanosis and polycythemia . \n also , previous hht series have shown an association between number of pulmonary avfs and cerebral abscess risk22 ) . \n this might explain why idiopathic pulmonary avfs are associated with a lower frequency of cerebral abscess than in hht . \n the organisms in the brain abscess were not consistent but most frequently isolated ones were streptococci genus . \n 6 cases out of 13 did not reveal an organism at all . if young adults without a premorbid history present with a brain abscess , pulmonary problems must be evaluated . \n this report highlights the need to consider pulmonary avf as an etiology of cerebral abscess when routine investigations fail to detect a source .", "role": "user" }, { "content": "brain abscess commonly occurs secondary to an adjacent infection ( mostly in the middle ear or paranasal sinuses ) or due to hematogenous spread from a distant infection or trauma . \n pulmonary arteriovenous fistulas ( avfs ) are abnormal direct communications between the pulmonary artery and vein . \n we present two cases of brain abscess associated with asymptomatic pulmonary avf . \n a 65-year - old woman was admitted with a headache and cognitive impairment that aggravated 10 days prior . \n an magnetic resonance ( mr ) imaging revealed a brain abscess with severe edema in the right frontal lobe . \n we performed a craniotomy and abscess removal . \n bacteriological culture proved negative . \n her chest computed tomography ( ct ) showed multiple avfs . \n therapeutic embolization of multiple pulmonary avfs was performed and antibiotics were administered for 8 weeks . a 45-year - old woman presented with a 7-day history of progressive left hemiparesis . \n she had no remarkable past medical history or family history . on admission , \n blood examination showed a white blood cell count of 6290 cells / ul and a high sensitive c - reactive protein of 2.62 mg / l . \n ct and mr imaging with mr spectroscopy revealed an enhancing lesion involving the right motor and sensory cortex with marked perilesional edema that suggested a brain abscess . \n a chest ct revealed a pulmonary avf in the right upper lung . \n the pulmonary avf was obliterated with embolization . \n there needs to consider pulmonary avf as an etiology of cerebral abscess when routine investigations fail to detect a source .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: as time goes by the revisional arthroplasty of hip is increased as the primary hip arthroplasty is increased . \n the most common reason for revisional arthroplasty is osteolysis and loosening of implant and it is more common in acetabular component problem than femoral component1 ) . \n severe segmental defect of acetabulum usually require structural allograft and reinforcement cage2 ) , peripheral metal augmentation or bilobed cup3 ) . \n but when peripheral rim of acetabulum is intact , jumbo cup with bone graft might be good option . \n whaley et al.4 ) defined jumbo cup as minimum 66-mm diameter in male patients and 62-mm diameter in female patients or 10-mm diameter lager than the contralateral hip . using of jumbo cup with porous coated in revisional arthroplasty make greater host bone contract and peripheral rim fixation456 ) . \n some authors suggested that for better fixation of jumbo cup , peripheral rim fixation of acetabulum is essential10 ) . in this study , we compared the implant survival rate of rim fixation group and no rim fixation group using jumbo cup to revisional arthroplasty . \n from january 2002 to march 2015 , 60 patients ( 60 hips ) had revisional arthroplasty of acetabular component for any reason in our institute . \n three patients who died within one year after revisional arthroplasty and four patients who were not followed for minimum one year were excluded . \n the mean follow up period was 51 months ( range , 12 to 154 months ) and mean age was 60.7 years ( range , 30 to 81 years ) . \n the mean weight was 60.1 kg ( range , 33 - 85 kg ) , the mean height was 158 cm ( range , 141 - 187 cm ) , and the mean body mass index was 23.2 kg / m ( range , 15.3 - 36.1 kg / m ) . \n the preoperative diagnosis was mainly aseptic loosening ( 76.5% ) , 2nd stage revision as infection ( 9.8% ) , acetabular protrusion ( 9.8% ) and recurrent dislocation ( 3.9% ) . \n the posterolateral approach was used in all operation . if medial cavitary bone defect is present , we performed morselized bone graft with autogenic or allogenic bone . \n the autogenic bone was obtained from ipsilateral iliac crest of pelvis and allogenic bone was fresh - frozen chip bone for commercial use . to prevent hip center change , we rimmed acetabulum inferiorly . \n the acetabular prosthesis was varied on the situation but mainly we used cementless porous coated acetabular cup ( 78.3% , bencox cup , corentec , cheonan , korea ; 8.1% , becox hybrid cup , corentec ) . \n the articulation was mostly ceramic on ceramic ( 41 hips ) . and ceramic on polyethylene ( 8 hips ) and metal on polyethylene ( 2 hips ) \n we divide the patients into two groups by acetabular rim fixation on initial postoperative anteroposterior and lateral plain radiograph . \n the rim fixation group is defined as superior and inferior rim is fitted with acetabular component on anteroposterior radiograph and anterior and posterior rim is fitted on lateral radiograph . \n the acetabular component position could not satisfy the above condition defined as no rim fixation group ( fig . \n 1 ) . and we evaluated early complication like aseptic loosening , injection , and osteolysis according to the criteria of engh et al.11 ) . \n as jumbo cup can cause hip center elevation , we evaluated hip center change between groups12 ) . \n after discharge , routine follow - up visits were scheduled for 6 weeks , 3 , 6 , 9 , and 12 months , and every 6 months thereafter . at every visit , we took radiographs and detail physical examination was done . \n the design and protocol of this retrospective study were approved by the institutional review board of our hospital . \n chi - square test was used for categorical variables , and student 's t - test for continuous variables . \n ibm spss statistics 20.0 for windows release ver . 20.0 ( ibm co. , armonk , ny , usa ) was used for all statistical calculations . \n the rim fixation group was 37 and no rim fixation group was 14 . there was no significant difference of characteristics between rim fixation group and no rim fixation group ( table 1 ) . \n six patients were parosky classification type 2a , 12 patients were type 2b , 10 patients were type 2c , and 9 patients were type 3a in rim fixation group . \n two patients were parosky classification type 2a , 7 patients were type 2b , 3 patients were type 2c , and 2 patients were type 3a in no rim fixation group . \n there is one patient who had aseptic loosening necessary to re - revision in rim fixation group and 3 patients in no rim fixation group ( fig . \n one patient had superficial infection in rim fixation group and one patient had periprosthetic fracture in no rim fixation group ( table 2 ) . \n we defined end - point of implant survival as any condition that need re - revision . \n the overall prosthesis survival rate was 97% in rim fixation group and 79% in no rim fixation group ( p=0.028 ) ( fig . \n the 3 patients of rim fixation group had osteolysis lesion in delee and chanley zone 1 and two patients of rim fixation group in zone 2 during follow up . \n we evaluated hip center change as using jumbo cup hip center might be change after operation . \n the radiologic superior migration of hip center is 12.14.5 mm in rim fixation group and 11.35.6 in no rim fixation group ( p=0.532 ) . \n lateral migration of hip center is 3.01.3 mm in rim fixation group and 2.31.5 mm in no rim fixation group ( p=0.212 ) . \n the hhs of no rim fixation group was lower ( 757.6 ) than rim fixation group ( 858.5 ; p=0.045 ) . \n but if peripheral rim is intact , using jumbo cup and cavitary bone graft may excellent option . \n gustke et al.14 ) reported 196 hips had revisional arthroplasty with jumbo cup and mean followed for 10 years , the survival rate was 96% . the other study report the survival rate of jumbo cup \n peripheral firm fixation is more required than polar contact though there are not mechanical study as we know15 ) . in this study \n , we find more good result in using of jumbo cup with peripheral rim fitting manner . as the cementless jumbo cup has large area to contract host bone , we can expect more host bone ingrowth14 ) . \n one patient had aseptic loosening in rim fixation group in 31 months after operation and three patients in no rim fixation group in 1 , 1 and 30 months after operation . \n the three cups were protruded into more medial side and rotated in one cup in no rim fixation group . \n the no rim fixation group had much weak fixation power than rim fixation group , so initial aceptic loosening occurred more than in rim fixation group \n . there were three patients who had osteolysis around cup in rim fixation group during follow up period . \n but these lesions was small size and made no difference in results . as we think , no progressing small osteolysis lesion is frequent in normal primary arthroplasty and this is because rim fixation group is three time more than no rim fixation group in this study . \n but we could not use jumbo cup in large acetabular defect like lacking of superolateral defect , the posterior column defect or pelvic discontinuity for example paprosky type iiib16 ) . and \n radiologic analysis showed a mean hip center elevation of 11 mm and average 1 mm of the measured hip center elevation than planned position at the interteardrop line . \n the elevated hip center may associated with hip instability , altered biomechanics and limb shortening18 ) . to prevent this problem , careful reaming starting with inferior acetabulum is required and if hip center elevation is detected during operation , adequate femoral stem and neck is necessary to compensate limb shortening . \n the implant survival rate is more superior in rim fixation group than no rim fixation group ( 97%>79% ) . \n the main problem of no rim fixation is rotation and medial protrusion of acetabular component because of weak medial support of bony structure . and if morselized bone graft is excessive in medial defect , the acetabular component is not well fixed withing peripheral rim , rim is protrude out of acetabular peripheral rim . \n the identification of rim fixation during operation is situationally difficult due to restricted visual field and sometimes bone graft may be confused as peripheral rim . \n occasionally results of plan radiograph shows no rim fixation even we confirmed rim fixation during the operation . \n this study is retrospective review and relatively small cases to statistical analysis and compare the survival rate between two groups . \n radiologic evaluation of peripheral rim fixation or not is subjective . but for more objectivity security , 1 radiologist and 2 orthopaedic board certificants participate in radiologic evaluation . \n screw fixation , cup position may also influence initial stability of implant , we did not took consider in this study . \n lastly , the acetabular component is no single production . but all acetabular component are cementless porous coated type and we did not used conventional polyethylene liner . \n although we need more follow period , using jumbo cup with peripheral rim fixation improves survival rate by acquiring maximal host bone contact in paprosky 2a , 2b , 2c , 3a acetabular defect .", "role": "user" }, { "content": "purposeit is challenging procedure to revise acetabular component in acetabulum with severe bone defect or deformity . \n the jumbo cup is good option for revisional arthroplasty in large bone defect . \n the purpose of this study is to compare the prognosis of revisional total hip arthroplasty using jumbo cup with peripheral rim fixation and no rim fixation.materials and methodswe included the patients who had performed acetabular revisional total hip arthroplasty from january 2002 to march 2015 in our institute . \n total of 51 hips ( 51 patients ) were included . \n the mean follow up period was 51 months ( range , 12 to 154 months ) and mean age was 60.7 years ( range , 30 to 81 years ) . \n we divided into two groups ( peripheral rim fixation group and no rim fixation group ) by anteroposterior and lateral plain radiograph . \n we compared survival rate , hip center change and clinical outcomes between two groups.resultsthere were 37 patients in peripheral rim fixation group and 14 patients in no rim fixation group . \n there was one patient who had aseptic loosening necessary to re - revision in rim fixation group and 3 patients in no rim fixation group . \n and one patient had superficial infection in rim fixation group and one patient had periprosthetic fracture in no rim fixation group . \n survival rate was higher in the peripheral rim fixation group ( 97.3% ) than no rim fixation group ( 78.6% , p=0.028)conclusionbased on our findings , peripheral rim fixation might be recommended to improve short - term outcome after revision total hip arthroplasty using jumbo cup .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: \n we investigated the gene expression profile during early and late stages of fasciola hepatica infection in balb / c mice . \n for this purpose , we have selected three experimental groups , each containing 3 mice . \n mice from group 1 served as controls and did not receive any treatment ; mice from groups 2 and 3 were orally infected with f. hepatica metacercariae and humanely euthanized and necropsied at 7 and 21 days after infection , respectively . \n we investigated the success of the infection by means of the detection of specific antibodies raised against the excretory / secretory antigen from f. hepatica at the time of necropsy . \n histopathological studies were performed from representative samples from the right and left liver lobes coming from each individual mouse . \n sections ( 4 m ) were stained with hematoxylin and eosin to determine the liver damage areas . \n the gen elute mammalian total rna miniprep kit ( sigma , san louis , usa ) was used to isolate the rna , following the manufacturer 's recommendations . \n both the quantity and quality of each rna sample was assessed with the agilent 2100 bioanalyzer ( agilent tech , palo alto , ca , usa ) . \n furthermore , only those samples with a rna integrity number ( rin ) higher than 7 were selected . \n the ambion wt expression kit for affymetrix genechip ( invitrogen ) was used to amplify and label the rna . \n after , it was hybridized to the genechip mouse gene 1.0 st array ( lot . \n washing and scanning were performed using the genechip instrument system of affymetrix ( genechip hybridization oven 640 , genechip fluidics station 450 and genechip scanner 3000 7 g ) . \n the 169-format genechip mouse gene 1.0 st array contained approximately 25 probes that were designed across the full length of 28,853 well - annotated genes for mouse . \n the design of the array was based on the february 2006 mouse genome sequence ( ucsc mm8 , ncbi build 36 ) with comprehensive coverage of refseq , putative complete cds genbank transcripts , all ensembl transcript classes and synthetically mapped full - length mrnas and refseq nms from humans and rats . \n the genechip mouse gene 1.0 st array has 100% coverage of nm sequences present in the april 3 , 2007 refseq database . \n the babelomics v4.2 platform was used to analyze raw data ( .cel files ) , which were generated after hybridization scanning , and image acquisition . \n after , the affymetrix raw data files ( .cel files ) were background - adjusted , normalized and log - transformed of the perfect match ( pm ) values using a robust multi - array average ( rma ) methodology for data normalization . \n differential gene expression , limma moderated t - statistics , reporting a t - test statistic for each gene together with its corresponding p - value ( generally called raw p - values ) was used . \n these raw p - values were further corrected for multiple testing to minimize the number of false positives in the study . in this analysis \n , we used the conventional multiple testing p - value correction procedures proposed by benjamini & hochberg to derive adjusted p - values . for functional profiling , \n each of the comparisons used here ( t0 vs t7 ; t0 vs t21 and t7 vs t21 ) wasanalyzed using logistic regression models to identify the functional blocks that were enriched in any of the conditions , . \n finally , the functional blocks from two databases , go biological process and kegg pathways , were used in the study . the ingenuity pathways analysis ( \n ipa ) software v6.0 was used to organize the genes that were regulated during the infection into networks of interacting molecules . \n the gene identifiers of the genes with a statistically significant change in expression ( p - value < 0.05 ) and with a calculated positive or negative fold change of at least two - fold were uploaded in the software . \n in addition , ipa was used for a functional analysis to identify the biological functions that were most significant to the uploaded datasets ( table 1 ) . the 1st strand cdna synthesis kit for rt - pcr ( amv ) ( cat . \n 1148318801 , roche ) was used to reverse transcribe each rna sample , according to manufacturer 's recommendations . for this purpose , \n six genes ( up- and down - regulated ) were randomly chosen and specific primers were designed using the primer - blast software ( http://www.ncbi.nlm.nih.gov/tools/primer-blast ) . \n a touchdown pcr ( td - pcr ) was performed with an initial denaturation at 94 c for 1 min , which was followed by a touchdown program for 16 cycles with successive annealing temperature decrements of 1.0 c every 2 cycles . \n for these 2 cycles , the reaction was denatured at 94 c for 20 s , which was followed by annealing at 61 c54 c for 30 s and polymerization at 72 c for 30 s. the subsequent 15 cycles of amplification were similar , except that the annealing temperature was 53 c . \n the td - pcr amplification was performed in a mastercycler gradient ( eppendorf ) and confirmed by electrophoresis . \n genomic dna contamination was ruled out for each rna sample by amplification of each rna sample without previous reverse - transcription step . \n we investigated the gene expression profile during early and late stages of fasciola hepatica infection in balb / c mice . \n for this purpose , we have selected three experimental groups , each containing 3 mice . \n mice from group 1 served as controls and did not receive any treatment ; mice from groups 2 and 3 were orally infected with f. hepatica metacercariae and humanely euthanized and necropsied at 7 and 21 days after infection , respectively . \n we investigated the success of the infection by means of the detection of specific antibodies raised against the excretory / secretory antigen from f. hepatica at the time of necropsy . \n histopathological studies were performed from representative samples from the right and left liver lobes coming from each individual mouse . \n sections ( 4 m ) were stained with hematoxylin and eosin to determine the liver damage areas . \n the gen elute mammalian total rna miniprep kit ( sigma , san louis , usa ) was used to isolate the rna , following the manufacturer 's recommendations . \n both the quantity and quality of each rna sample was assessed with the agilent 2100 bioanalyzer ( agilent tech , palo alto , ca , usa ) . \n furthermore , only those samples with a rna integrity number ( rin ) higher than 7 were selected . \n the ambion wt expression kit for affymetrix genechip ( invitrogen ) was used to amplify and label the rna . \n after , it was hybridized to the genechip mouse gene 1.0 st array ( lot . \n washing and scanning were performed using the genechip instrument system of affymetrix ( genechip hybridization oven 640 , genechip fluidics station 450 and genechip scanner 3000 7 g ) . \n the 169-format genechip mouse gene 1.0 st array contained approximately 25 probes that were designed across the full length of 28,853 well - annotated genes for mouse . \n the design of the array was based on the february 2006 mouse genome sequence ( ucsc mm8 , ncbi build 36 ) with comprehensive coverage of refseq , putative complete cds genbank transcripts , all ensembl transcript classes and synthetically mapped full - length mrnas and refseq nms from humans and rats . \n the genechip mouse gene 1.0 st array has 100% coverage of nm sequences present in the april 3 , 2007 refseq database . \n the babelomics v4.2 platform was used to analyze raw data ( .cel files ) , which were generated after hybridization scanning , and image acquisition . \n after , the affymetrix raw data files ( .cel files ) were background - adjusted , normalized and log - transformed of the perfect match ( pm ) values using a robust multi - array average ( rma ) methodology for data normalization . \n differential gene expression , limma moderated t - statistics , reporting a t - test statistic for each gene together with its corresponding p - value ( generally called raw p - values ) was used . \n these raw p - values were further corrected for multiple testing to minimize the number of false positives in the study . in this analysis \n , we used the conventional multiple testing p - value correction procedures proposed by benjamini & hochberg to derive adjusted p - values . for functional profiling , \n each of the comparisons used here ( t0 vs t7 ; t0 vs t21 and t7 vs t21 ) wasanalyzed using logistic regression models to identify the functional blocks that were enriched in any of the conditions , . \n finally , the functional blocks from two databases , go biological process and kegg pathways , were used in the study . the ingenuity pathways analysis ( \n ipa ) software v6.0 was used to organize the genes that were regulated during the infection into networks of interacting molecules . \n the gene identifiers of the genes with a statistically significant change in expression ( p - value < 0.05 ) and with a calculated positive or negative fold change of at least two - fold were uploaded in the software . \n in addition , ipa was used for a functional analysis to identify the biological functions that were most significant to the uploaded datasets ( table 1 ) . \n the 1st strand cdna synthesis kit for rt - pcr ( amv ) ( cat . no . \n 1148318801 , roche ) was used to reverse transcribe each rna sample , according to manufacturer 's recommendations . for this purpose , six genes ( up- and down - regulated ) were randomly chosen and specific primers were designed using the primer - blast software ( http://www.ncbi.nlm.nih.gov/tools/primer-blast ) . \n a touchdown pcr ( td - pcr ) was performed with an initial denaturation at 94 c for 1 min , which was followed by a touchdown program for 16 cycles with successive annealing temperature decrements of 1.0 c every 2 cycles . \n for these 2 cycles , the reaction was denatured at 94 c for 20 s , which was followed by annealing at 61 c54 c for 30 s and polymerization at 72 c for 30 s. the subsequent 15 cycles of amplification were similar , except that the annealing temperature was 53 c . \n the td - pcr amplification was performed in a mastercycler gradient ( eppendorf ) and confirmed by electrophoresis . \n genomic dna contamination was ruled out for each rna sample by amplification of each rna sample without previous reverse - transcription step .", "role": "user" }, { "content": "fasciolosis is listed as one of the most important neglected tropical diseases according with the world health organization and is also considered as a reemerging disease in the human beings . \n despite there are several studies describing the immune response induced by fasciola hepatica in the mammalian host , investigations aimed at identifying the expression profile of genes involved in inducing hepatic injury are currently scarce . \n data presented here belong to a time - course investigation of the gene expression profile in the liver of balb / c mice infected with f. hepatica metacercariae at 7 and 21 days after experimental infection . \n the data published here have been deposited in ncbi 's gene expression omnibus and are accessible through geo series accession number gse69588 , previously published by rojas - caraballo et al . \n ( 2015 ) in plos one [ 1 ] .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: the physicochemical properties of nanoscale composite are a result of molecular interaction between materials of interest , such as a conducting polymer , promoting greater structural control of the formed films [ 13 ] . \n two of the most used methods to obtain nanostructured materials in the solid state are the langmuir - blodgett ( lb ) technique and the process of layer - by - layer ( lbl ) assembly . \n this last one emerges as a method of deposition of alternating layers formed through the electrostatic interaction between oppositely charged solutions , where the formation of the first monolayer on the substrate surface occurs initially through a process of adsorption . \n in addition to the possibility of controlling the structure formed at the supramolecular level , the lbl technique has the advantage of not requiring any sophisticated equipment or procedures such as the lb technique . \n the technological interest of several research groups in composites , and more recently in nanocomposites , comes mainly from the mechanical properties and biodegradability , which are both characteristic of natural polymers , allied to the conductive properties of some synthetic polymers , which provides a great versatility of applications in areas such as engineering , biotechnology , and medicine [ 68 ] . \n natural gums are macromolecules formed from units of sugars , monosaccharides , linked by glycosidic bonds resulting in natural polymers with long chains and high molecular weight \n . the gums may originate from plants exudates ( e.g. , arabic gum and cashew gum ) , seaweed extract ( e.g. , agar ) , animal ( e.g. , chitosan ) , seeds ( e.g. , guar gum ) , and others . \n the gum from exudates is produced in epithelial cells confined in the ducts of the trees that are released spontaneously or induced as a defense mechanism of the plant [ 10 , 11 ] . \n the natural gums interact with water in two different ways : by retention of water molecules ( thickness effect ) or by building networks that enhance the connection areas ( effect of gelation ) . \n because of these behaviors , the gums are also known as hydrocolloids [ 12 , 13 ] . the cashew gum ( anacardium occidentale l. ) is particularly interesting because it is an exudate obtained from the cashew tree , very abundant in the northeast of brazil . \n it belongs to the same family of arabic gum , widely used in the food industry , and presents similarities in their composition and in their physicochemical properties [ 1214 ] . cashew gum ( cg ) is an acidic polysaccharide complex composed of a main chain of -galactose ( 13 ) with branches of -galactose ( 16 ) , with the terminal residues glucuronic acid , arabinose , rhamnose , 4-o - methylglucuronic acid , xylose , glucose , and mannose . \n brazilian gum main constituents are galactose ( 73% ) , arabinose ( 5% ) , rhamnose ( 4% ) , glucose ( 11% ) , glucuronic acid ( 6.3% ) , and residues of other sugars ( less than 2% ) [ 12 , 14 ] ( scheme 1(a ) ) . additionally , the terminal glucuronic acids in the structure of the gum are responsible for the anionic nature of the material when in aqueous solution . \n cashew gum has antimicrobial properties for therapeutic treatment , as well as thickening and emulsifying properties [ 15 , 16 ] used in foods and drugs industry . \n these characteristics are due to its heterogeneous structure and high molecular weight of the polysaccharide chain , which interacts strongly with water , creating an effect of thickening or gelling in solution . \n the polyaniline ( pani ) belongs to the class of conducting polymers with high technological interest due to their potential applications as electroluminescent devices , corrosion protection , sensors , and biosensors [ 17 , 18 ] . \n the versatility of pani is due to changes of its oxidation state , hence its electrical conductivity , which occurs rapidly and reversibly , and its chemical stability [ 19 , 20 ] . \n the applications of polyaniline are limited by its poor solubility in aqueous media in its conductive form [ 17 , 20 ] . a proposed solution for this limitation \n was given by geng et al . who prepared a water - soluble conductive polyaniline through the introduction of hydrophilic dopant such as phosphonic acid ( pa ) in the polymeric chain . \n the pa is a mixture of acids mono- and bihydroxyl phosphonate at 1 : 1 molar ratio ( 1 ) . \n thus , the longer the hydrophilic chain of the conducting polymer , the higher its solubility in water , generating new applications : in this study , lbl films were produced with pani or pani - pa and the natural cashew gum ( cg ) in a bilayer fashion ( pani / cg)n or ( pani - pa / cg)n ( where n is the number of bilayers ) \n . films containing a conventional anionic polyelectrolyte , for example , poly(vinylsulfonic acid ) pvs , were compared to cashew gum in the ( pani / pvs)n or ( pani - pa / pvs)n films . \n we also investigated the ability of these nanocomposites to act as modified electrodes for dopamine sensing . \n cashew gum , collected in the state of cear ( northeast region of brazil ) , was isolated and purified using sodium salt , as described by costa et al . . \n afterwards 0.25 ml of ethanol was added to 5.0 g of cashew gum , which was immediately dissolved in 100 ml of milli - q water under stirring for 12 h , followed by filtration . \n pani was synthesized by the oxidative polymerization of aniline doubly distilled in 1.0 mol l hcl solution containing a proper amount of ammonium persulfate ( ( nh4)2s2o8 , vetec ) . \n the product was maintained in ammonia hydroxide ( vetec ) for 12 hours to obtain pani in the form of emeraldine base ( eb ) . \n the mixture of mono- and bihydroxyl acids designated as pa , with molecular average weight of 896 g mol , was prepared as reported by geng et al . . \n for the processing of polyaniline solutions , 0.47 g pani - eb powder ( with or without pa dopant ) was dissolved in 25 ml dimethylacetamide ( dmac , vetec ) under stirring for 12 h. the solutions were filtered and slowly added to 26 ml of hcl solution , and the ph was adjusted at 2.8 . \n poly(vinyl sulfonic acid ) ( pvs ) was purchased from aldrich co. and used without previous purification in aqueous solutions at a concentration of 0.5 mg ml and ph 2.8 . \n ultrapure water with a resistivity of 18.3 m cm ( milli - q , millipore ) was used for preparation of all solutions . \n nanostructured layered films were assembled in a bilayer fashion using pani or pani - pa as polycationic solutions in conjunction with cg or pvs as polyanionic solutions . \n the deposition of each layer consisted in the immersion of the substrate in the dipping solution for 5 min , followed by rinsing in the washing solution ( hcl , ph 2.8 ) and drying in n2 flow . \n lbl films with four distinct architectures were investigated : ( pani / pvs)n , ( pani - pa / pvs)n , ( pani / cg)n , and ( pani - pa / cg)n where n is the number of bilayers . \n multilayer films with n = 2 , 4,6 , and 8 were obtained onto glass covered with indium tin oxide ( ito ) , ( scheme 1(b ) ) . \n electrochemical measurements were carried out using a potentiostat autolab pgstat30 and a three - electrode electrochemical cell with 10 ml . a 1.0 cm platinum foil and saturated calomel electrode ( sce ) were used as auxiliary and reference electrodes , respectively . \n the lbl films onto ito ( 0.4 cm ) were used as the working electrode . \n all the experiments were performed in inert n2 atmosphere at 22c in an electrolytic solution of 0.1 mol l hcl . \n pani - ap / gc lbl film containing 6 bilayers ( n = 6 ) was subjected to dopamine ( da ) detection using cyclic voltammetry in electrolytic solution containing 10 to 230 mol l of da and sweep rate of 50 m vs. after the measurement the film tested was exhaustively washed with electrolytic solution and the reproducibility was investigated . furthermore , the effects of the interfering ascorbic acid ( aa ) in the presence of da were also studied using different proportions of aa and da . \n cyclic voltammograms of ito unmodified and modified electrodes with lbl film produced with poly(allylaminehydrochloride ) , pah , and the natural cashew gum , ( pah / cg)6 , were obtained in hcl 0.1 mol l and are shown in figure 1 . under our experimental conditions , it is observed that the ito substrate has no electrochemical response to the potential range studied . \n however , the modified substrate with ( pah / cg)6 shows that the presence of the lbl film activates the electrode surface increasing the double electrical layer of this system and therefore catalyzes the processes of oxygen evolution observed in the forward sweep and hydrogen evolution observed in the reverse sweep . the increase in current values is observed in the potential in which these processes occur . \n a previous study about the influence of the size and nature of this anion in the supporting electrolyte for the systems studied here was carried out in hcl or h2so4 , both at 0.1 mol l , with scan rate of 50 mv s. the processes of oxidation and reduction , characteristic of conducting polymer , were shifted to more positive potentials in h2so4 media when compared to the profile obtained in hcl solution ( data not shown ) . the potential difference observed for this redox process was 0.05 v. according to matveeva et al . \n , both the processes of oxidation and reduction ( e \n red and e \n ox ) and the distance between the potential at which these transitions occur are dependent on the substrate used and the size and nature of the anion of the supporting electrolyte employed . the potential shift observed for the pani in h2so4 reflects a limitation in the processes of charge transfer across the interface between ito and polymeric film and also in the interface polymeric film and the electrolyte . probably this limitation of the charge transfer process could be related to differences in mobility and the steric hindrance originated from the anionic species present in both electrolytes studied , having hso4 \n and so4 \n for sulfuric acid and cl for hydrochloric acid , respectively . it was also noted that the degradation processes of pani were more intense and were best defined in h2so4 ( data not shown ) . \n this observation is likely to be explained by the fact that h2so4 is a more oxidant acid than hcl intensifying the processes observed . \n thus , the whole study presented in this paper was performed in optimized conditions of hcl media . \n figure 2 shows the cyclic voltammograms obtained for the bilayers films containing the conductive polymer interspersed with cashew gum or pvs in hcl media . the electrochemical profile recorded for the lbl systems \n ( pani / pvs)6 ( pani - pa / pvs)6 , ( pani - gc)6 , and ( pani - pa / cg)6 ( figure 2 ) indicates the presence of two redox processes characteristic of pani that correspond to interconversions in their states of oxidation . during the direct scan there was the transition from leucoemeraldine state to emeraldine pani , e \n pa1 , with the expulsion of the proton , and the transition from emeraldine to pernigraniline , e \n pa2 , was accompanied by the capture of the anion , cl . during the inverse sweep two reduction processes were observed ; pernigraniline to emeraldine , e \n pc2 , accompanied by the expulsion of the anion and emeraldine to leucoemeraldine , e \n pc1 , which was accompanied by proton uptake . \n an intermediate process between the transitions related above is defined as acidic degradation of pani with the formation of benzoquinone ( oxidation ) and hydroquinone ( reduction ) pair . \n the electrochemical behavior for the systems in figure 2 shows that the interactions between the pani or pani - pa with pvs and cg do not suppress the electroactive and electrochemical properties observed and described for polyaniline . \n the films of pani and pani - pa interspersed with pvs showed the three well - known oxidation processes of pani and a fourth oxidation process observed in the region of 0.86 v ( figures 2(a ) and 2(b ) ) . \n this fourth oxidation was not observed for films in which pvs was replaced by cg in the multilayer structure ( figures 2(c ) and 2(d ) ) . \n the oxidation process at 0.86 v can be explained as the result of an interaction between the cationic groups of pani with anionic groups of pvs . the phosphonic acid ( pa ) used in this study acts as both a modifying agent pani , increasing its solubility , and a dopant acid promoting a further increase in current values observed in the redox processes of pani - pa ( figures 2(a ) and 2(c ) ) . \n this increase in current values contributes to providing an enhancement in selectivity of the pani - pa / pvs and pani - pa / cg systems compared to pani / pvs and pani / cg , and thus the presence of pa becomes an important factor to be considered in analytical determinations using electrochemical techniques . for the films pani - pa / pvs ( figure 3(a ) ) and pani - pa / cg ( figure 3(b ) ) with 2 , 4 , 6 , and 8 bilayers , \n the cyclic voltammograms obtained at 50 mv s reveal that the increase in the number of bilayers is reflected in the increase of current values . \n this result indicates an increment in the amount of material adsorbed on the substrate as the number of bilayers increases . \n when pvs was replaced by cashew gum ( figure 3(b ) ) the fourth oxidation process disappeared because the interaction between pani and pvs disappeared as well . \n the interaction between these pani and pvs can occur by two distinct mechanisms , similarly as proposed by raposo & oliveira for lbl films of poly(o - methoxyaniline ) ( poma ) and pvs . \n this process can occur through the establishment of links between pani and psv in the presence of electrical charge ( scheme 2(a ) ) and/or in the absence of electrical charge through the formation of networks of water molecules from the pani present in solution with pvs ( scheme 2(b ) ) . \n probably the adsorption processes proposed for the pani and pvs must be somehow related to the oxidation process observed in the region of 0.86 v in figure 3(a ) . in our studies we observed that the presence of cashew gum significantly decreases the degradation of the polymer in acid media , which is observed in films pani - pa / pvs around 0.43 v ( shown in figures 2(a ) and 3(a ) ) . in figure 4 the cyclic voltammograms of the films with 6 bilayers of pani - pa / pvs ( figure 4(a ) ) and pani - pa / cg ( figure 4(b ) ) the 5th and the 20th successive cycles of scanning potential at 50 mv s are shown . \n the electrode polarization until 0.90 v led to a more visible degradation of the conducting polymer in system pani - pa / pvs . \n cyclic voltammograms for these films show the presence of intermediate redox process around 0.43 v , which is related to soluble products ( radical benzoquinone / hydroquinone ) formed during the acid degradation of polyaniline accompanied by a decrease of the current values in all the processes observed . on the other hand \n , the process for proton expulsion and anion uptake seems more stable for the pani - pa / cg film even after twenty successive cycles . \n therefore , the polyaniline suffers acid degradation , promoted by the high polarization potential and by electrolyte of hcl , and in the case in the pani - pa / pvs system this process is enhanced by the presence of pa modifier . on the other hand , when pvs was replaced by cg the degradation process of pani was reduced indicating that the cashew gum protects the film from the degradations processes mentioned above , presenting a greater stability during scanning in an acid medium and polarizations at 0.90 v compared to pani - pa / pvs or pani / pvs films studied . \n previous works from our group showed that lbl films of poma and gums have greater stability during scanning potential in an acid medium than films poma / pvs and that the gums as chich ( sterculia striata ) and angico ( anadenanthera macrocarpa b. ) act protecting the polymer film from this degradation . \n the process of charge transfer from the ito - modified electrode with pani - pa / cg film containing 6 bilayers was studied by varying the scan rate ( v ) in the range of 10 to 150 m v s ( data not shown ) . in these conditions it was observed that the values of the anodic peak current ( i \n pa1 ) increased linearly with scan rate for the film pani - pa / cg , according to the equation i \n pa1(a ) = 1.92(0.76 ) + 0.30(0.010 ) v ( mv s ) , with a linear correlation , r = 0.998 . \n this behavior indicates a redox process of electroactive species that are strongly adsorbed on the ito surface , confirming that the electrochemical reaction is controlled by a kind of electron hopping mechanism of charge transfer on the electrode surface . \n the dependence on ph solution of the electrochemical behavior of pani - pa / cg film was studied and shown in figure 5 . when increasing the ph from 1 to 2 an approximation of pani redox process occurs , and in ph 3.0 and 4.0 it is possible to observe the overlap of two redox processes at 0.30 v and 0.20 v for ph 3.0 and at 0.48 v and 0.10 v for ph 4 . \n on the other hand at ph 5 the pani - pa / cg film no longer presents any electrochemical activity . \n however , when the same film was scanned again at ph 1.0 it presented the characteristic processes of electroactive polyaniline with potential and current values similar to the first scan done at ph 1.0 before variations in ph described above . \n this reversibility in the electrochemical behavior in function of the ph media is not observed in films of pani / pvs or pani - pa / pvs . \n thus , the results suggest that in the case of pani - pa / cg films , the cashew gum acts as a stabilizing element of the polyaniline . \n lbl films of cashew gum containing modified polyaniline with pa dopant are very interesting for applications in electrochemical sensors due to their high reproducibility and stability . \n thus , the self - assembled film of pani - pa / cg containing 6 bilayers was selected to be applied to detect dopamine ( da ) , an important neurotransmitter in the central nervous system of mammals [ 34 , 35 ] . \n figure 6(a ) shows the cyclic voltammograms for the lbl film with 6-bilayers of pani - pa / cg in different concentrations of dopamine ( da ) . in this figure a redox couple ( e \n pa2/e \n pc ) appears associated with oxidation of dopamine in dopamine quinone at 0.63 v and its reduction at 0.29 v [ 34 , 35 ] . \n the anodic current peak ( i \n pa2 ) increases linearly for concentrations of da between 0.01 and 0.23 mmol l for the modified electrode , as shown in the calibration curve in figure 6(b ) . \n the calibration equation obtained by linear regression is i \n pa2(a ) = 0.15(0.043 ) + 23.10(0.37 ) [ da]/mmol l with a correlation coefficient ( r ) equal to 0.998 ( for n = 10 ) and sensibility of 23.10 a mmol l. the limit of detection ( ld ) of 1.5 10 mol l was estimated using 3/slope ratio , where is the standard deviation calculated from 10 blank samples and slope refers to the slope of the calibration curve , according to the iupac recommendations . \n the modified electrode presented reversibility after washing and a good repeatability for da determinations with relative standard deviation , rsd = 6% in five determinations in the presence of 0.23 mmol l da . \n table 1 summarizes the analytical performance on different modified electrodes for da detection by electrochemical process [ 2732 ] . \n the lowest ld obtained was observed for film from ( pani - pa / cg)6 , revealing itself as a competitive electrode for this analysis when compared to other modified electrodes . \n the relationship of peak current ( i \n pa2 ) for da oxidation with the scan rate ( v ) has been investigated for 6 bilayers from pani - pa / cg film in 0.1 mol l hcl solution in the presence of 0.23 mmol l da ( data not shown ) . under these conditions \n a linear relationship between anodic current peak ( i \n pa2 ) and the square root of scan rate ( v \n ) for the pani - pa / cg film was found according to the equation i \n pa2(a ) = 0.27(0.14 ) + 2.32(0.02 ) v \n ( mv s ) , r = 0.999 . \n this behavior indicates that the electrocatalytic process of electron transfer is controlled by dopamine diffusion from the solution to the redox sites of pani - pa / cg films . in order to investigate the selectivity of the pani - pa \n / cg modified electrode , we tested the simultaneous detection of 0.01 mmol l da in different ascorbic acid ( aa ) concentrations , the natural interfering of da . \n it is noted in figure 7 that when we increase the concentration of aa a proportional increase in the current values at 0.45 v is accompanied . moreover , in the oxidation potential of dopamine , 0.63 v , the increase of current with the addition of aa is minimal , showing that oxidation of dopamine at the surface of modified electrode is slightly affected by trace amounts of aa ( figure 7 ) . \n additionally it is important to observe that this new nanocomposite using cashew gum , which is a natural and biocompatible polymer , in the multilayer structure , gives rise to new applications as biosensor [ 38 , 39 ] . \n additionally , this film could be used in wound repair because it has been shown that very small exogenously applied electrical currents produce a beneficial therapeutic result for wounds . in this work \n we propose a formation of electroactive nanocomposite , which can be a potential tool for wound repair when associated with the electrostimulation . \n the electrochemical profiles observed for the films studied showed the redox intrinsic characteristic transitions of polyaniline . \n the presence of cg increases the electrochemical stability of the film , suggesting that it acts by protecting the conductive polymer from acid degradation . \n lbl films of pani / pvs and pani - pa / pvs show an oxidation process around 0.86 v , which can be related to interaction between pani and pvs . \n detailed studies showed that the electrochemical reaction in the pani - pa / cg film is governed by a charge transfer mechanism at the surface electrode via electron hopping . \n the ito - modified electrode with pani - pa / cg film showed high reproducibility and stability , encouraging its use as a sensor of da . \n this modified electrode was able to detect electroactive molecule of da around 0.63 v in detection limits consistent with the pharmaceuticals formulations .", "role": "user" }, { "content": "we take advantage of polyelectrolyte feature exhibited by natural cashew gum ( anacardium occidentale l. ) ( cg ) , found in northeast brazil , to employ it in the formation of electroactive nanocomposites prepared by layer - by - layer ( lbl ) technique . \n we used polyaniline unmodified ( pani ) or modified with phosphonic acid \n ( pa ) , pani - pa as cationic polyelectrolyte . on the other hand , the cg or polyvinyl sulfonic ( pvs ) acids were used as anionic polyelectrolytes . \n the films were prepared \n with pani or pani - pa intercalated with cg or with pvs alternately resulting in four films with different sequences : pani / cg pani - pa / cg , pani / pvs and pani - pa / pvs , respectively . \n analysis by cyclic voltammetry ( cv ) of the films showed that the presence of gum increases the stability of the films in acidic medium . \n the performance of the modified electrode of pani - pa / cg was evaluated in electro analytical determination of dopamine ( da ) . \n the tests showed great sensitivity of the film for this analyte that was detected at 105 mol l1 .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: hydrogen ( h2 ) , a colorless , tasteless , odorless , non - irritating , and highly flammable diatomic gas , was generally regarded as physiologic inert gas in hyperbaric medicine . in 1975 and 2001 , dole et al . \n ( 2001 ) separately reported that h2 under a high pressure might be a therapeutic gas for cancer and parasite - induced liver inflammation by eliminating toxic ros . in 2007 , ohsawa et al . \n ( 2007 ) found that 2% h2 inhalation exhibited antioxidant and anti - apoptotic activities by selectively reducing cytotoxic oxygen radicals . \n the importance of h2 immediately drew widespread concerns and it is proved to be effective for many ros - related diseases , such as hepatic and cardiac hypoxia ischemia injury , inflammation injury caused by small intestine transplantation and neonatal hypoxia \n , 2007 ; buchholz et al . , 2008 ; cai et al . , 2008 ; hayashida et al . , \n , other ways to administrate h2 , such as drinking h2-saturated water , intraperitoneal and intravenous injection of h2-saturated saline , were also effective to many disorders , such as cerebral hypoxia ischemia injury , human type ii diabetes , nephrotoxicity induced by cisplatin , parkinson 's disease and atherosclerosis in apolipoprotein ( cai et al . , 2009 ; chen et al . , 2009 ; mao et al . , 2009 ; \n sun et al . , 2009 ; zheng et al . , 2009 ; oharazawa et al . , 2010 ) \n all these evidences show that molecule h2 is effective to diseases related to oxidative stress , which may include chronic obstructive pulmonary disease ( copd ) . \n chronic obstructive pulmonary disease is a complex multifactorial disease mainly composed of chronic bronchitis and pulmonary emphysema , which is characterized by not fully reversible airflow limitation . \n the major feature of copd is generally accepted as abnormal response to injury , chronic inflammation , excessive activation of macrophages , neutrophils , t lymphocytes , and fibroblasts in the lung . \n people even with mild copd often manifest physiological abnormalities that lead to breathlessness and reduction in exercise tolerance , while moderate and severe copd may remarkably affect the quality of life and mortality . \n there are many treatments for copd , such as inhalational corticosteroid ( ics ) and anticholinergics , salmeterol \n however , until now none of them was proved to be an ideal treatment for copd . \n anticholinergics treatment showed a higher risk of cardiovascular morbidity and mortality ( singh et al . , 2008 ) . \n in another study , tiotropium was showed unable to reduce the decline of fev1 ( tashkin et al . , 2008 ) . \n regarding the fact that copd morbidity and mortality has been increasing in recent years , it would be greatly valuable to find out an effective therapy to copd . \n oxidative stress is widely proposed as a pathogenic mechanism for copd ( van der vliet , 1999 ; pinamonti et al . , 1996 ; repine et al . , 1997 \n many researchers found markers of oxidative stress , such as h2o2 and no , in the epithelial lining fluid , breath , and urine of copd patients ( dekhuijzen et al . \n oxidant peroxynitrite , generated by the reaction of no with superoxide anion , is reported to be highly correlated with copd ( kanazawa et al . , 2003 ) . \n weiss reaction and fenton reaction , is also a strong toxic oxidant ( halliwell and gutteridge , 1986 , 1992 ) . \n ichinose found abundant nitrotyrosine positive staining cells and inos positive cells in induced sputum of copd patients , indicating that oxidative stress caused by reactive nitrogen species may be exaggerated in the airways in copd patients and overproduction of reactive nitrogen species may contribute to pathogenesis of copd ( ichinose et al . , 2000 ) . \n first , oxidative stress , such as h2o2 and isoprostane f2a - iii formed by free radical peroxidation of arachidonic acid , may induce reversible airway narrowing by constricting airway smooth muscle ( kawikova et al . \n finally , oxidative stress can lead to a proteinase antiproteinase imbalance ( park et al . , \n our hypothesis is that h2 may be a unique , effective , and specific treatment for copd . \n given the fact that h2 can eliminate ros such as oh and onoo and ros is an important factor in the pathogenic process in copd , we hypothesize that h2 may be potentially effective for copd by preventing its occurrence , exacerbation , and slowing its process . \n first , because of its small molecular weight , h2 can easily penetrate bio - membranes and diffuse into cytosol , mitochondria , and nucleus . \n second , as h2 selectively reacts with oh and onoo other important ros ( e.g. , h2o2 and ) involved in cell signaling are not decreased , so the metabolic oxidation reduction reactions are not disturbed . \n people have inhaled h2 for hundreds of years in diving and it is already proved to be very safe for inhalation . moreover , inhaled h2 can easily reach the lung to play a therapeutic role . in addition , because of the special anatomical structure of lung , h2 can reach lung cells easily and quickly ; furthermore , if h2 inhalation is applied as a treatment , h2 will act on lung directly , leading to a better therapeutic effect . in conclusion , as copd has shown an increase in mortality in recent years , we hope h2 will successfully control the tread due to its potential protective effect . \n the authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest .", "role": "user" }, { "content": "the protective effect of hydrogen ( h2 ) on ros - induced diseases has been proved by many researches , which demonstrated that through eliminating oh and onoo , h2 could effectively attenuate lipid and dna peroxidation , improve cellular antioxidant capacity , and then protect cells against oxidant damage . \n most of free radicals in human body are ros , including o2,oh , h2o2 , no,onoo , and so on . under normal circumstances cells \n are able to maintain an adequate homeostasis between the formation and removal of ros through particular enzymatic pathways or antioxidants . \n but under some pathological conditions , the balance is disturbed , leading to oxidative stress and various diseases , such as chronic obstructive pulmonary disease ( copd ) . \n studies have shown that ros played a pivotal role in the development of copd and some antioxidants were effective in the protection against the damaging effects of oxidative stress . \n therefore , we hypothesize that owing to its peculiarity to eliminate toxic ros , hydrogen therapy may be a novel and effective treatment for copd .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: ever since antiquity the values linked to the practice of the medical professionalism ( mp ) have been stated and defined by various professional oaths , starting with the well - known hippocratic oath . over the centuries and with the evolution of the mp in modern and postmodern society , \n the ethical values underpinning these oaths have gradually changed.[25 ] world 's leading medical organizations have recently updated and explained the definition of mp . in this context , the relationship between the physician and the patient is a core issue : a review produced by several medical associations in europe and in united states stresses that the patient physician relationship is a surrogate marker to assess the role of mp . \n although the knowledge and internalization of the values connected to the mp are fundamental requirements for professional practice at any level , the studies concerning this topic have mostly been carried out among fully trained professionals or in the advanced phases of specialized training . on the contrary \n there are still very few data available about medical students of the medical doctor ( md ) degree in medicine . in this paper \n the medical student is considered as a sensor accepter of the values of mp , investigating by questionnaire the awareness of the values of the medical profession and the way these values are taught . \n students were also asked to express their point of view on the methods to improve their educational level linked to ethical values of mp . \n the survey was held between may and june 2010 at the md degree in medicine and surgery at padua university , in collaboration with the association of medical practitioners , surgeons and dental practitioners of padua in italy . \n four hundred twenty three students ( 169 males and 254 females ) were involved , out of a total population of about 1200 students in the first , fourth , and fifth years of the md degree ; 52.0% of them ( n = 220 ) attending the first year of the md degree , 23.8% ( n = 101 ) the fourth year and 24.2% ( n = 102 ) the fifth year of the md degree . \n the investigation on this group allowed a direct evaluation of the ideas and initial expectations of those who choose to follow a career in medicine and surgery . \n fourth - and fifth - year students already have some cultural and practical experience that may influence their perception of the values of the mp in various ways . \n second - and third - year students were excluded from the survey , as they are supposed not to have had any practical activity in the wards yet . it was presumed that students do not significantly alter their perception of the mp , unless for personal reasons ( e.g. , one of their relatives is a physician ) , as long as they lack direct clinical and health care experience . \n sixth - year students were not included in the survey due to the difficulty of recruiting them , as they have no lessons in the second semester of the md degree . \n questionnaires were given to students in the classrooms , just before the beginning of lessons . \n the participation in the study was voluntary , and supplying personal identification information such as names or student identification numbers was optional . according to the physician charter on mp , students were asked to fill an anonymous questionnaire , composed of seven questions [ table 1 ] on the values [ table 2 ] of the mp . \n the values were translated into italian language and accompanied by a brief explanation , supplied on the first page of the questionnaire . \n this was done in order to reduce variability in the possible personal interpretations of the items , following an internationally agreed line of interpretation . \n list of the values and professional skills of the medical profession for questions 1 , 2 , 4 , 5 [ table 1 ] students were asked to assign a score using the likert scale from 0 to 5 ( where 5 was the maximum ) . in question 1 \n they were asked to express a score for each of the 13 values . in questions 3 , 6 , and 7 they had to express their preferences between the items \n proposed , as follows : 3 preferences out of 13 items to questions 3 and 6 , and 2 preferences out of 6 items to question 7 [ tables 2 and 3 ] . \n methods proposed by the questionnaire for further learning in general the questionnaire dealt with ( 1 ) the knowledge of values and professional skills , ( 2 ) the importance of the values of the medical profession , and ( 3 ) how values and skills are taught . \n pearson 's chi - square test was used for dichotomous variables , while for ordinal variables the wilcoxon rank sum test was used for comparison by gender and the kruskal \n questionnaires were given to students in the classrooms , just before the beginning of lessons . \n the participation in the study was voluntary , and supplying personal identification information such as names or student identification numbers was optional . according to the physician charter on mp , students were asked to fill an anonymous questionnaire , composed of seven questions [ table 1 ] on the values [ table 2 ] of the mp . \n the values were translated into italian language and accompanied by a brief explanation , supplied on the first page of the questionnaire . \n this was done in order to reduce variability in the possible personal interpretations of the items , following an internationally agreed line of interpretation . \n list of the values and professional skills of the medical profession for questions 1 , 2 , 4 , 5 [ table 1 ] students were asked to assign a score using the likert scale from 0 to 5 ( where 5 was the maximum ) . in question 1 \n they were asked to express a score for each of the 13 values . in questions 3 , 6 , and 7 they had to express their preferences between the items \n proposed , as follows : 3 preferences out of 13 items to questions 3 and 6 , and 2 preferences out of 6 items to question 7 [ tables 2 and 3 ] . \n methods proposed by the questionnaire for further learning in general the questionnaire dealt with ( 1 ) the knowledge of values and professional skills , ( 2 ) the importance of the values of the medical profession , and ( 3 ) how values and skills are taught . \n pearson 's chi - square test was used for dichotomous variables , while for ordinal variables the wilcoxon rank sum test was used for comparison by gender and the kruskal \n the survey stressed quite a high level of knowledge and self - awareness about the values and skills of mp . \n as for question 1 [ table 1 ] , the median value was 4 - 5 for all years of dc in both genders . \n after stratification by course year , the values of sensitivity ( p = 0.0371 ) , integrity ( p = 0.0098 ) , professional skills of communication and shared decision making ( p = 0.0054 ) , compassion and empathy ( p=<0.0001 ) , and managing conflicts of interest ( p = 0.0076 ) are better known between the fourth - and fifth - year students than first - year students . on the contrary , \n first - year students declare to know the professional skills and values at a higher level than those of the fourth and fifth years of dc ( p = 0.0267 ) . \n gender differences are to be considered as well : female students gave emphasis to the values of altruism ( p = 0.0147 ) , respect ( p = 0.0045 ) , sensitivity ( p = 0.0318 ) , confidentiality ( p = 0.0309 ) , communication and shared decision making ( p = 0.0132 ) , integrity ( p = 0.011 ) , duty ( p = 0.0054 ) , managing conflicts of interest ( p = 0.019 ) more than males students . \n no statistically significant gender - based difference was found for accountability , compassion and empathy , self - awareness , and ongoing professional development . more than 70% of students , agreed in attributing a high importance level ( likert scale score 5 ) to the application of all the values / skills of mp in clinical practice ( question 2 ) , especially female rather than male students ( p = 0.0025 ) . \n for the main part of students the values of respect , accountability and the professional skills of competence are fundamental in clinical practice ; on the contrary the values of self - awareness and confidentiality and the professional skills of managing conflicts of interest , compassion and empathy are considered as less important [ figure 1 ] . \n considering the different years of md degree , the values of confidentiality ( p = 0.0188 ) and integrity ( p = 0.0125 ) and the professional skills of communication and shared decision making ( p = 0.0242 ) were more significantly distributed in fourth - and fifth - year students than in those of the first year ; the value of competence was also more significant ( p = 0.0045 ) in the former than in the latter . \n the students globally consider that the values / skills are poorly taught and not so present in their educational experience ( question 4 ) . \n the level of teaching values / skills was generally marked as low : likert score of 3 or less was 48% for first - year students , 52% for fourth - year students and \n the level of teaching was found especially low ( likert score of 2 or less ) by the students of the fifth year [ figure 2 ] : more than 30% of fifth - year students attributed a likert value 2 to this question , while for first- and fourth - year students the most frequent score was 3 . compared to their younger colleagues , senior students seem to be more skeptical about the actual importance given to ethical values within teaching programs . \n essential values by course year degree of teaching by course year students generally judged that teaching values / skills is fundamental for clinical practice ( question 5 ) : more than 50% of them responded to question 5 with the top score of the likert scale . \n the usefulness of teaching values and skills was more evident for female rather than male students ( 58% vs. 46.5% , p = 0.0017 ) . \n male students instead showed a higher and more significant interest for ongoing learning than females ( p = 0.0427 ) . \n ( basically , a physician - patient relationship based on trust ) is given more emphasis by fourth - and fifth - year ( p = 0.0366 ) ( question 6 ) : we may argue that senior students , who already have some clinical experience , have already be faced to complex physician \n patient relationships ( e.g. , the patient 's lack of confidence in the physician 's skills , or even in medical science in general ) . as regards the methods to improve teaching of values / skills [ question 7 , table 2 ] , more than 70% of the students required more practical activity in the hospital department , in direct contact with the patient . \n the students also consider that they could take advantage from the experience of young specializing physicians , being tutored by senior students or just having more opportunities of dialogue and exchange . \n this is considered as more useful by first - year student ( p = 0.0062 ) rather than those of fourth and fifth years of md degree . \n the main part of the students seem to prefer seminars in small groups , and therefore a more direct student professor approach , rather than the classic magisterial lessons . \n students of the fourth and fifth year would especially appreciate role - plays , that is a kind of cooperative learning based on the simulation of possible every - day situations . \n learning - by - experience method in small groups are especially requested by senior students , who had practical lessons in the ward , already experienced overcrowding around the patient 's bed during the exercises followed from the 4 year onward [ figure 3 ] . \n as for gender - based differences , male students are more interested than female in role playing . \n in this study students declared to have a good knowledge and awareness of the values and skills related to the mp and considered them very important in their learning . \n as expected the knowledge of the values and skills progressively increases during the years of md degree , demonstrating that lessons and clinical experience improves their sensitiveness and perception of these elements . \n the most considered professional skills are altruism , ongoing professional development , sense of duty , and competence and among the values respect and accountability . \n these values are core issues of the patient - centered approach , characterized by a global relationship between the physician and the patient . the patient , as well as the physician , is not regarded as an object of medical profession , but as an actor . \n this model shifts the physician 's point of view : his attention is no longer focused exclusively on the patient 's illness , but rather on the patient himself . in this approach it is therefore fundamental to learn how to create a relationship and a therapeutic alliance with the patient . \n factors such as respect , sensitivity for individual differences , altruism , confidentiality , compassion , empathy , integrity , accountability , commitment , self - awareness , and competence all contribute to determine the outcome of the therapeutic intervention . despite the high interest of students , \n the basic values of mp appear to be poorly developed during their studies in medicine and surgery . \n students particularly requested more intensive activity in the ward with the patient , stressing the importance of learning by experience . \n also the possibility of hearing first - hand accounts from junior specialist physicians would be appreciated , with regard to their human , rather than technical , experience ; this is probably due to the fact that junior specialist physicians are seen as being closer to the student 's own situation . \n the interest for learning techniques such as role playing might arise from the practical difficulty encountered in the direct contact with patients , so it may be considered as a complementary or support activity . \n lastly there is a clear request for a more direct and personal approach to these themes , rather than just classic classroom lesson . faced with these data \n , we should now consider what would be the correct tools to deepen the knowledge of mp . \n some aspects of communication and self - awareness , for example , can be dealt with in theoretical lessons . but how can one set about teaching \n students shall have the opportunity to learn about a real patient - centered approach , and to directly observe the benefits coming from this approach , as well as its critical points . in this way future physicians could also find scientific reasons for a commitment in this direction , and \n shall be more aware of the importance of the care relationship as a therapeutic instrument . \n just as the tradition of medical teaching has established over the centuries , first - hand experience is fundamental , although requiring a more time and commitment . as confirmed by literature in the field , learning to communicate effectively , feeling and showing respect and empathy , building up a therapeutic relationship based on confidentiality and joint responsibility are educational goals that can be only reached through the various forms of learning by experience : learning directly from an expert model during training or activities in the ward , role playing with eventually making a video recording to be watched afterward , practicing with fellow students in exercises involving pairs or groups , being supervised by a more expert tutor during activities with patients . \n ongoing evaluation is to be implemented as well : these activities should be backed up by a reflection on what has been done , possibly within a small group . \n students would thus become more aware of and the effects of their own actions , and would develop new and more effective ones , also thanks to the contribution of their fellows . \n all the above aspects need to be favored in developing countries as has emerged from recent literature . \n the student of the md degree requires a widespread educational process for the mp involving the acquisition of specific competences ( e.g. , empathy , self - awareness ) . \n ethical values and human skills have been considered as core issues of mp , but the acquisition of professional skills and the awareness of ethical values were considered as an implicit consequence of the practice . \n the results of the study are in line with recent choices of the medical school faculty of the university of padua , were new courses were implemented , focusing on human aspects of medical education.[2426 ] finally teaching methods should be harmonized with the contents and with the educational needs to ensure a more complex patient - based approach and the classical lectures of teachers should be more integrated with learning through experience methods .", "role": "user" }, { "content": "background : the values such as participation / empathy , communication / sharing , self - awareness , moral integrity , sensitivity / trustfulness , commitment to ongoing professional development , and sense of duty linked to the practice of the medical professionalism were defined by various professional oaths.aims:the aim of this study was to evaluate how these values are considered by the students of the degree course of medicine.materials and methods : four hundred twenty three students ( 254 females , 169 males ) taking part of the first , fourth , and fifth years of the degree course in medicine were asked to answer seven questions . \n pearson 's chi - square , wilcoxon rank sum test , and kruskal wallis test were used for the statistical analysis.results:the survey showed a high level of knowledge and self - awareness about the values and skills of medical profession . in particular , the respect , accountability , and the professional skills of competence were considered fundamental in clinical practice . however , the students considered that these values not sufficiently present in their educational experience.conclusions:teaching methods should be harmonized with the contents and with the educational needs to ensure a more complex patient - based approach and the classical lectures of teachers should be more integrated with learning through experience methods .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: with the development of science and network technology , searching for information and contacting by email has become more convenient for us . \n but when this network came to be overused , a phenomenon called internet addiction ( ia ) occurred.1 globally , users of internet have already crossed the 3 billion mark.2 people s republic of china has 256 million adolescent internet users as of january 2014 , accounting for 71.8% of the overall number of adolescents.3 internet addiction disorder ( iad ) , now more commonly called problematic internet use , compulsive internet use , internet overuse , problematic computer use , and pathological computer use , was first proposed by the american psychiatrist goldberg ; it is a phenomenon caused by excessive use of the network and leads to social psychological damages . \n the american psychologists beard and wolf,4 also proposed that iad refers to the factor of this phenomenon is the network itself , such as network communication and some low - quality content online.5 some researchers found that iad is associated with personality,68 self - esteem,9,10 social support,9 suicide ideation , disordered eating attitudes,11 defense styles,12 depressive symptoms,3 physiological.6 although official diagnostic criteria do not exist , ia can be defined as the excessive , obsessive compulsive , uncontrollable , use of internet , which also causes significant distress and impairments in daily functioning.13 it is imperative to recognize the antecedents of ia.14 about 25% of users fulfill ia criteria within the first 6 months of using the internet . \n many individuals initially feel intimidated by the computer , and gradually feel a sense of competency and exhilaration from mastering the technology and learning to navigate the applications quickly by visual stimulation . \n the feeling of exhilaration can be explained by the way iad sufferers often describe themselves as : bold , outgoing , open - minded , intellectually prideful , and assertive.4 the prevalence rates of ia in hong kong adolescents ranged from 17% to 26.8% during the high school years.15 researchers have tried to find out the determinants or risk factors associated with ia . \n male,16 stage of education , daily time spent on using internet , most frequent time of internet use , monthly cost of use , and tea consumption17 were some of the factors found to be associated with ia . \n this study aims to investigate the status of the use of internet of university students in anhui province , so as to offer useful information for prevention and intervention in the treatment of adolescent iad . \n cluster sampling method was used to select 5,249 participants who came from four junior high schools and four high schools in anhui ( people s republic of china).18 in the people s republic of china , the education is divided into three categories : basic education , higher education , and adult education . \n basic education in people s republic of china includes preschool education , primary education , and regular secondary education . \n secondary education is divided into academic secondary education and specialized / vocational / technical secondary education . \n academic secondary education consists of junior high school ( grade range 79 ) and high school ( grade range 1012 ) . the questionnaire consisted of general information ( school , sex , age , grade , ethnicity , family location , height , weight , whether only child , etc ) and self - assessment ia scale ( ia test).19 ia test consisted of 20 items , and each item was rated on a 5-point scale ranging from very rarely ( 1 ) to very frequently ( 5 ) . \n total score of all items was interpreted as follows : 50 points as iad group and < 50 points as non - iad group . \n this study was conducted in close cooperation with the main heads of schools . after they granted permission for the classroom survey , the survey \n was then conducted in four middle schools and one university ; all primary teachers at each educational class were informed and invited to participate with their respective class . before participation , the students received written and oral information about the study , including information about confidentiality and the right not to participate . \n the survey was supervised by a member of our research team who also answered questions from the students . \n participants were well - informed on the scope and extent of the survey and consent of the parents was also obtained . \n epidata 3.0 software ( http://www.epidata.dk/ ) was used to establish a database and entry data ; spss 20.0 ( ibm corporation , armonk , ny , usa ) software was used for data analysis ; chi - square test was used to compare the detection rate of iad in adolescents for different variables . \n all participants were informed about the study , and written informed consent was obtained from both the schools and parents / students guardians . \n cluster sampling method was used to select 5,249 participants who came from four junior high schools and four high schools in anhui ( people s republic of china).18 in the people s republic of china , the education is divided into three categories : basic education , higher education , and adult education . \n basic education in people s republic of china includes preschool education , primary education , and regular secondary education . \n secondary education is divided into academic secondary education and specialized / vocational / technical secondary education . \n academic secondary education consists of junior high school ( grade range 79 ) and high school ( grade range 1012 ) . \n the questionnaire consisted of general information ( school , sex , age , grade , ethnicity , family location , height , weight , whether only child , etc ) and self - assessment ia scale ( ia test).19 ia test consisted of 20 items , and each item was rated on a 5-point scale ranging from very rarely ( 1 ) to very frequently ( 5 ) . \n total score of all items was interpreted as follows : 50 points as iad group and < 50 points as non - iad group . \n this study was conducted in close cooperation with the main heads of schools . after they granted permission for the classroom survey , the survey \n was then conducted in four middle schools and one university ; all primary teachers at each educational class were informed and invited to participate with their respective class . before participation , \n the students received written and oral information about the study , including information about confidentiality and the right not to participate . \n the survey was supervised by a member of our research team who also answered questions from the students . \n participants were well - informed on the scope and extent of the survey and consent of the parents was also obtained . \n epidata 3.0 software ( http://www.epidata.dk/ ) was used to establish a database and entry data ; spss 20.0 ( ibm corporation , armonk , ny , usa ) software was used for data analysis ; chi - square test was used to compare the detection rate of iad in adolescents for different variables . \n all participants were informed about the study , and written informed consent was obtained from both the schools and parents / students guardians . \n in our results , the overall detection rate of iad and non - iad in students was 8.7% ( 459/5,249 ) and 76.2% ( 4,000/5,249 ) . \n table 2 reveals that the detection rate of iad in males ( 12.3% ) was higher than that of females ( 4.9% ) , and the detection rate of iad was statistically different between students from rural ( 8.2% ) and urban ( 9.3% ) areas , among students from different grades , between students from only - child family ( 9.5% ) and non - only - child family ( 8.1% ) , and among students from different family types . \n the development of internet has made a great effect on our work , study , and life , as well as created a series of social problems . \n recently , research found that the prevalence of ia is 6.0% among adolescent internet users.20 we also obtained similar results in our study , where the overall detection rate of iad was 8.7% . additionally , the detection rate of ia in male students was higher than female students , the possible reason being maybe that personality and behavior are different between males and females . \n this difference between the two sexes may also explain that males are more involved in online activities , such as gaming , pornography , and gambling , which can lead to pathological internet use . \n in this study , the incidence of ia for students from the rural and urban areas was significantly different , which may be explained by the fact that adolescents from rural areas have less opportunity to access internet . \n the results also showed that the detection rate of teen ia among different grades was significantly different . \n the possible reason may be that higher grade students are more comfortable with surfing the internet and faced less constraints from their parents . \n our survey showed that ia rate of only - child students is higher than that of non - only - child students . \n the chinese communist party government has been forcefully promoting its one - child policy for 3 decades . \n one - child policy in the city performed better than rural areas , thus the only - child proportion in the city is much higher than in rural areas . in recent years , \n computer and internet ownership has dramatically increased in cities , which promotes internet use for students . \n this study also suggests that the incidence of students ia is different among different family types . \n in addition , students living with their fathers have a higher incidence of ia , which could be caused by lack of mothers education and care . for adolescents , \n the purpose of mental health education is physical and mental development of youth in a scientific way , which can effectively help teenagers to improve self - control , promote self - regulation and persuasion , and resist the temptation of internet . \n in addition , the health education department should help teenagers understanding of the network , distinguish the differences between real world and online world , and correct their own attitude toward the internet . in single - parent families , children have higher incidence of ia . \n children can not get enough warmth from a single parent , which hinders the development of children s healthy personality and comprehensive quality . \n internet provides children a free and open space ; they get freedom of spirit and mental catharsis on the internet . \n the desire for communication makes them escape from real life , and to gradually be addicted to the internet . \n parents should create a warm and harmonious family environment , so that children experience a feeling of warmth from the family . \n for adolescents , the purpose of mental health education is physical and mental development of youth in a scientific way , which can effectively help teenagers to improve self - control , promote self - regulation and persuasion , and resist the temptation of internet . \n in addition , the health education department should help teenagers understanding of the network , distinguish the differences between real world and online world , and correct their own attitude toward the internet . in single - parent families , children have higher incidence of ia . \n children can not get enough warmth from a single parent , which hinders the development of children s healthy personality and comprehensive quality . \n internet provides children a free and open space ; they get freedom of spirit and mental catharsis on the internet . \n the desire for communication makes them escape from real life , and to gradually be addicted to the internet . \n parents should create a warm and harmonious family environment , so that children experience a feeling of warmth from the family . \n for adolescents , the purpose of mental health education is physical and mental development of youth in a scientific way , which can effectively help teenagers to improve self - control , promote self - regulation and persuasion , and resist the temptation of internet . \n in addition , the health education department should help teenagers understanding of the network , distinguish the differences between real world and online world , and correct their own attitude toward the internet . \n children can not get enough warmth from a single parent , which hinders the development of children s healthy personality and comprehensive quality . \n internet provides children a free and open space ; they get freedom of spirit and mental catharsis on the internet . \n the desire for communication makes them escape from real life , and to gradually be addicted to the internet . \n parents should create a warm and harmonious family environment , so that children experience a feeling of warmth from the family . \n iad has more effect on male students , single - child families , single - parent families , and higher grade students . \n more care must be taken of male students , only - child students , and students living with their fathers , and related education should be strengthened for susceptible subjects of iad .", "role": "user" }, { "content": "background and aimthe purpose of this study was to describe the characteristics and prevalence of internet addiction ( ia ) in adolescents so as to provide a scientific basis for the communities , schools , and families.methodswe conducted a survey by randomized cluster sampling on 5,249 students , grades ranging from 7 to 12 , in anhui province , people s republic of china . \n the questionnaire consisted of general information and ia test . \n chi - square test was used to compare the status of ia disorder ( iad).resultsin our results , the overall detection rate of iad and non - iad in students was 8.7% ( 459/5,249 ) and 76.2% ( 4,000/5,249 ) , respectively . \n the detection rate of iad in males ( 12.3% ) was higher than females ( 4.9% ) . \n the detection rate of iad was statistically different between students from rural ( 8.2% ) and urban ( 9.3% ) areas , among students from different grades , between students from only - child families ( 9.5% ) and non - only - child families ( 8.1% ) , and among students from different family types.conclusionprevalence of ia is high among chinese adolescents . \n iad has more effect on male students , single - child families , single - parent families , and higher grade students . \n we should take more care of male students , only - child students , and students living with their fathers , and related education should be strengthen for susceptible subjects of ida .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: embryologically the thyroid gland is derived from 2 anlages : a large median endodermal anlage and two lateral anlages . \n the median anlage produces most of the thyroid parenchyma , while the lateral anlage is derived from the fourth pharyngeal pouch and contributes 1% to 30% of the thyroid weight ( 1 ) . \n commonly , failure in the descent of the median anlage results in a lingual thyroid gland . in rare cases , \n failure of the lateral anlage to fuse with the median anlage can result in lateral ectopic thyroid gland ( 2 ) . \n we present a case report of a 54-yr - old woman with presumed metastatic papillary thyroid carcinoma ( ptc ) of lateral neck nodes , as was expected from clinical and computed tomography ( ct ) findings . \n total thyroidectomy with left modified radical neck dissection ( mrnd ) was performed , but histological examination of the mass at the lateral neck showed ectopic thyroid tissue with a hyperplastic pattern . \n a 54-yr - old female presented with palpable masses in the left lateral neck region . physical examination revealed two firm , non - tender , mobile masses of 33 cm size and 44 cm , respectively . \n a ct scan of the head and neck with contrast was done , which showed a mass ( 22 cm ) with calcification on the left lobe of the thyroid , and also revealed that the two palpable masses at the left lateral neck were enhanced with calcification on the left level ii ( 3.54.5 cm ) and iii ( 3.54 cm ) ( fig . \n fine - needle aspiration biopsy ( fnab ) of the mass at left lateral level ii resulted in fibroadipose tissues , but suggested lateral neck metastasis of ptc , as evidenced by calcification and cystic change on ct scan , and a fnab of the calcified nodule at the left lobe of thyroid consisted of intranuclear inclusion , which was indicative of ptc . \n the patient underwent total thyroidectomy with left mrnd under the presumptive diagnosis of lateral neck metastasis of ptc . \n the two masses at level ii and iii had calcification and cystic change , which is sufficient evidence of neck metastasis . however , unlike nodal metastasis of ptc , which is gray , these masses were homogeneous and pink ( fig . \n the pathologic diagnosis of the nodule at the left lobe of the thyroid was ptc without capsular invasion , and the mass in the left lateral neck was an ectopic thyroid gland with a hyperplastic pattern ( fig . \n four nodes of the central compartment and five nodes of left level iv and v were not malignant . \n ectopic thyroid gland is defined as thyroid tissue not located anterolaterally in the second to fourth tracheal cartilages . \n the lingual location is most common , accounting for 90% of reported cases ( 2 - 4 ) . \n ( 5 ) reported multifocal papillary thyroid carcinoma occurring very rarely in a lingual thyroid . \n an ectopic thyroid gland in the region of the submandibular gland and intra - trachea is also very rare ( 6 , 7 ) . \n other rare sites of an ectopic thyroid gland include the mediastinum , esophagus , lung , heart , aorta , and abdomen . \n differential diagnosis between lingual thyroid tissue and metastatic thyroid cancer may be difficult . on inspection , the surface of the lingual thyroid may be smooth or irregular . \n occasionally , large blood vessels are present on the surface of lingual thyroid tissue , predisposing it to ulceration and hemorrhage ( 9 ) . \n most detailed histological studies have shown that lingual thyroid tissue characteristically has an incomplete or poorly defined capsule . \n therefore , benign lingual thyroid tissue may appear malignant due to what appears to be an invasion into the muscle , but this only signifies a defect in the capsule , resulting in intermingling of the glandular and the muscular elements . \n one year after the operation , a diagnostic radioiodine scan showed a significant residual uptake at the level of the chin , thought to be consistent with a metastasis at the base of the tongue . \n incisional biopsy was done , and histological examination showed numerous follicular structures , and a diagnosis of ectopic thyroid was made . \n interestingly , a kinetic analysis of iodine turnover in lingual thyroid tissue showed a biological half - life of 1.3 days compared with 100 days in normal thyroid tissue ( 10 ) . \n this phenomenon may explain why the lingual thyroid in the present patient was so resistant to ablation , compared with the remnant tissue in the thyroid bed . in our case report , we described a patient with ptc who had two ectopic lateral thyroid glands in the neck masquerading as a metastatic focus . \n in fact , ectopic thyroid glands of the midline , like lingual thyroid , are not easily mistaken for metastatic ptc , because it is almost impossible for metastasis of ptc at level i of the neck to skip over levels ii , iii , and iv . however , \n if ptc is combined with lateral neck masses with calcification , why did someone suggest it was an ectopic thyroid at the lateral neck ? \n however , since it is impossible for suspected calcified masses of the lateral neck to be an ectopic thyroid , mrnd must be performed in such cases . \n currently , there are a relatively large number of reports on ectopic thyroid , but there are few articles that present ectopic thyroid coexisting simultaneously with ptc . if a preoperative diagnostic method could be developed that can differentiate between ectopic thyroid tissue and metastatic thyroid cancer , an accurate assessment of the extent of operation would be made .", "role": "user" }, { "content": "ectopic thyroid glands generally occur in the midline as a result of abnormal median migration , and their presence lateral to the midline is rare . \n we present one case of an ectopic thyroid gland masquerading as a lateral neck metastasis of a papillary thyroid carcinoma ( ptc ) . in this case of a 54-yr - old woman with left ptc , we suspected left lateral neck metastasis on preoperative neck computed tomography . \n the patient underwent total thyroidectomy , central compartment neck dissection , and left modified radical neck dissection ( mrnd ) . \n the patient was diagnosed as having an accessory thyroid gland on the lateral neck on the final pathologic report . \n surgeons should be aware of the existence of an ectopic thyroid gland in unusual locations .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: stinging nettle ( urtica dioica l. ) has a long history as one among plants foraged from the wild and eaten as a vegetable [ 1 , 2 ] . \n although not fully domesticated , the species remains popular even in the current era for food and medicine as reported , for example , in nepal and poland . despite u. dioica being recognized as an edible and highly nutritious vegetable , \n research attention has focused more on its value as a source of alternative medicine and fiber . \n clinical trials have confirmed the effectiveness of nettle root and saw palmetto ( serenoa repens ( bart . ) small ) fruit extracts in the treatment of benign prostatic hyperplasia . \n dried nettle leaf preparations are also known to alleviate symptoms associated with allergic rhinitis , and a technology for granulating lipophilic leaf extracts for medicine has been developed . \n a recent report from ongoing work in italy confirms the potential of u. dioica as a sustainable source of textile fiber . \n there are a number of reports that address the role of u. dioica in human nutrition . \n fatty acid and carotenoid content in leaf , stem , root , and seed samples have been measured , and the properties of phenolic compounds in leaves , stalks , and fibers have been reported . furthermore , the quality and safety and microbiological properties of sucuk , a turkish dry - fermented sausage , incorporating dried u. dioica leaf have been studied , and the capacity of nettle extracts to improve oxidative stability in brined anchovies has been reported . in the basque region of spain , \n young shoots are reportedly eaten raw or included in omelets . in terms of postharvest processing for long - term storage , \n microwave drying at 850 w was found to be the best method for preservation of leaf color , energy consumption , and processing time . \n mineral content and trace metal concentrations in nettle leaf tea made by infusion or decoction have also been determined . \n however , nettle is consumed primarily as a fresh vegetable whereby it is added to soups , cooked as a pot herb , or used as a vegetable complement in dishes . in this sense , more work needs to be done on nutritive value of fresh nettle , and the fate of minerals and bioactive compounds in processed products . \n this information is essential because the capacity of fresh nettle to irritate bare skin may discourage potential consumers and postharvest processing methods that make it safe to handle , while maintaining nutritive value will benefit the development of u. dioica as a specialty vegetable . in this study \n , we report dietary values , mineral properties , and other quality attributes of raw , blanched , and cooked stinging nettle . \n plant samples were obtained from field plots planted as a part of an ongoing agronomic study on u. dioica at randolph farm ( 37.1n ; 77.3w ) , virginia state university ( vsu ) . \n samples from fall and spring growth were collected in october 2011 and may 2012 , respectively , by harvesting actively growing shoots ( 20 2 cm ) before the onset of flowering . \n individual shoots were clipped with a pair of shears and consolidated in vented plastic bags before transfer to a demonstration kitchen located at the vsu farm pavilion for further processing . in the kitchen , \n the shoots were washed , and twelve 200 5 g units were weighed before separating leaves and tender shoot tips from the woody stem . the edible portion ( leaves and tender shoot tips ) was weighed , and mean yield was determined by presenting the weight of edible portion as a percentage of total unit mass . \n treatments , each replicated three times , were applied as follows : raw samples were packaged and frozen without further processing , blanched samples were immersed in boiling water ( 98 - 99c ) for 1 min , and cooked samples were boiled ( 98100c ) with or without salt ( 5 gl h2o ) for 7 min . both blanched and cooked samples were cooled to 0c with shaved ice immediately after treatment . \n samples for proximate composition analysis were submitted frozen , while those for fatty and amino acid analysis were freeze - dried and ground to a fine powder before analysis . \n all analysis was done according to the association of analytical chemists ( aoac ) methods ( aoac , 2000 ) . \n nitrogen ( n ) content was measured using a cn analyzer ( leco 528 , leco corp . , st . \n joseph , mi ) , and protein content was derived by multiplying n values with 6.25 . \n total fat was determined by gas chromatography ( agilent 5890 , agilent technologies , santa clara , ca , usa ) after extraction of saponifiable and unsaponifiable fractions , and ash content was measured by ignition at 550c to constant weight . \n total dietary fiber was determined following methods described by the american association of cereal chemists ( aacci method 32 - 07.01 ) . \n total vitamin a and vitamin a as -carotene were determined by colorimetry after alkaline digestion followed by extraction with hexane . \n vitamin c was extracted in acid and sample content determined by titration . for mineral analysis , \n samples were subjected to wet digestion before calcium , iron , and sodium content was determined using an icp spectrometer ( aoac , 2000 ) . for amino acid analysis , a ground subsample of nettle tissue was hydrolyzed with 6 m hcl at 100c for 24 hr as previously described . \n acid hydrolyzed amino acids were derivatized with phenyl isothiocyanate ( acros organics , geel , belgium ) and separated using a 2695 alliance hplc equipped with a 15-cm pico - tag column , 2487 uv / vis detector , and empower software ( all from waters corp . , milford , \n amino acid concentrations are expressed in g/100 g of nettle leaf . fatty acid methyl esters ( fames ) \n were prepared by treating raw and processed samples with ethyl chloride and absolute methanol as described . \n fatty acid methyl esters were analyzed by gas chromatography using an agilent 6890 n gc system ( agilent technologies ) , equipped with a hp - innowax column ( 30 m 0.32 mm i.d . \n peaks were identified against retention times for a known fame and quantified by the aid of heptadecanoic acid ( 17:0 ) included as an internal standard . \n the concentration of each fatty acid is presented as a percentage of total saponifiable oil in sample . \n one - way analysis of variance ( anova ) using the analyst function in sas ( version 9.2 for windows , sas institute , cary , nc ) was performed to compare the effects of blanching and cooking on stinging nettle quality and nutritive value . \n treatments were treated as independent variables , and data for fall 2011 and spring 2012 were analyzed separately . \n tukey 's hsd ( p < 0.05 ) was used to separate treatment means within season . \n actively growing stinging nettle shoots are ideally harvested before flowering for consumption as a potherb or spinach alternative . \n leaves on stems were found to be tender enough for use as a vegetable up to 25 cm from the growing point , but stems become woody about 4 cm away from the growing point necessitating destemming after harvest to separate the tender tip ( approx . 4 cm and leaves ) from the woody stem . \n our results show that the woody stem portion accounts for 23%30% of total biomass with edible portion comprising of 70% or more of harvested material ( table 1 ) . \n yield ( edible portion ) was higher in fall than in spring samples because of seasonal differences in u. dioica growth characteristics . \n consistent with published observations , u. dioica displays two distinct phenological stages when grown in south - central virginia : reproductive growth up to late spring , limited development during summer , and mostly vegetative growth in the fall . \n after draining , there was not much difference in moisture content between raw and processed samples in the fall of 2011 , while there was slightly more moisture in processed samples in the spring of 2012 , likely due to differences in draining time . \n there was a slight reduction in crude protein , ash , and fat after blanching or cooking in both fall and spring samples . in both cases , \n the most significant reductions were observed with longer exposure to heat and also to salt . \n samples harvested in the spring contained significantly higher values for all parameters measured and showed higher decline after processing ( table 2 ) . \n for example , cooking significantly reduces ash , carbohydrate content , and calorific value in cocoyam ( colocasia esculenta ) leaves , while chopping amaranth ( amaranthus sp . ) leaves before cooking can result in increased loss of vitamins and minerals . \n our results show that vitamin a , calcium , and iron contents in u. dioica leaf are similarly affected by cooking . \n sodium content was low and was not affected by cooking , but the salt added to cooking water in one of the treatments significantly ( p < 0.05 ) increased sodium content in drained samples ( table 2 ) . \n salt addition for seasoning or preservation has been reported to affect vegetable quality through dilution of minerals and other chemical changes . \n cooking led to changes in the fatty acid profile of u. dioica with more saturated fat being converted into mono - unsaturated and polyunsaturated forms ( table 3 ) or lost into solution . \n saponifiable oil content in raw and processed u. dioica samples ( 3.2%4.7% in the spring ; 3.2%4.1% in the spring ) was comparable to that in wild asparagus ( asparagus acutifolius ) and black bryony ( tamus communis ) , edible wild greens common to mediterranean diets . \n data on individual amino and fatty acid content in stinging nettle shows that the species can supply significant quantities of oleic ( 18:1 ) , linoleic ( 18:2 ) , and -linoleic ( 18:3 ) acids and is a good source of unsaturated fatty acids . \n considerable amounts of palmitic acid ( 16:0 ) , a saturated fatty acid , were found in the leaf ( table 3 ; figure 1 ) . there were no significant differences in fatty acid content between samples collected from fall and spring growth . \n similarly blanching and cooking with or without salt did not affect fatty acid content within season except for a general trend showing an increase in unsaturated fatty acid content and a corresponding decrease in the concentration of saturated fatty acids ( table 3 ) . \n similarly , high levels of linoleic and -linoleic acids in young and mature leaves and the presence of relatively high concentrations of the same oils in u. dioica seed , stem , and roots portions have been reported , with the seed containing up to 15% saponifiable oil . in terms of omega-3 \n fatty acid content , u. dioica compares favorably with frozen spinach ( spinacia oleracea l. ) pretreated by steaming , blanching , or autoclaving . \n relative to other commonly consumed wild plants , it contains a higher concentration of omega-3 fatty acids than borage ( borago officinalis ) , and about the same level as water - blinks ( montia fontana ) , watercress ( rorippa nasturtium - aquaticum ) , sheep sorrel ( rumex acetosella ) , and sorrel ( rumex induratus ) . however , carbohydrate content ( including total sugars ) was significantly lower in raw and processed u. dioica ( 4.2%16.5% ) than in the four species above reported to constitute 66.6%78.9% total carbohydrates . \n these results show that processing by blanching and cooking has a minimal impact on u. dioica fatty acid composition , implying that it can be a good source of essential fatty acids when eaten as a leafy vegetable . with regard to individual amino acids , \n our results show that u. dioica can supply considerable amounts of essential amino acids including threonine , valine , isoleucine , leucine , phenylalanine , and lysine , along with lower concentrations of histidine and methionine ( table 4 ; figure 1 ) . \n amino acid content was largely unchanged in the spring as compared with fall growth though asparagine , glutamine , leucine , and histidine levels were generally lower in samples from spring growth . \n there were slight to significant increases in amino acid content after blanching or cooking in fall samples , but no similar observation was made for samples collected in the spring ( table 4 ) . \n there may be differences between and within species in response to postharvest handling and processing conditions . \n in one study , a significant increase in amino acid content was recorded after cooking relative to raw spinach , while the opposite was true for cooked and frozen versus raw brussels sprouts . \n data from this experiment show that both raw and cooked u. dioica can be important sources of dietary protein . \n the species can supply higher concentrations of essential amino acids than brussels sprouts and has a better amino acid profile than most other leafy vegetables . \n although similar to s. oleracea in terms of total amino acid content , u. dioica contains higher levels of all essential amino acids except leucine and lysine . some of the published recipes incorporating u. dioica leaf flour in bread , pasta , and noodle dough suggest that it can be used as a protein - rich supplement in starchy diets associated with poor and undernourished populations . \n this is because on a dry weight basis , u. dioica leaf is better than almond ( dry ) and is comparable to common bean ( phaseolus vulgaris ) and chicken ( gallus gallus ) as a source of essential amino acids . \n the agronomic properties of u. dioica including perennial growth , quick response to fertilization , and high biomass yield make it an excellent candidate for low - cost mass production for such a purpose . \n results from this study show that u. dioica retains a significant portion of minerals , vitamins , and essential nutrients after pre - treatment by blanching or cooking prior to frozen storage . \n processing may be the most effective approach to availing the nutritional benefits of u. dioica to consumers discouraged by the stinging quality of live or fresh nettle . \n the nutritional information in figure 2 , representing means of data from both spring and fall growth , can be used to label frozen raw and processed u. dioica leaf . \n however , lower vitamin a and higher carbohydrate content and other data reported for blanched u. dioica samples collected from the wild show that more work is required to evaluate the properties of u. dioica products as affected by interactions between landrace , environment , harvesting time , and processing conditions . \n although the usage of u. dioica as a leafy vegetable is widespread , there is little information on processing potential , and the impact of different processing methods on nutritive and functional value . \n the results presented in this report show that u. dioica retains significant amounts of minerals , vitamins , and other functional values after blanching or cooking . \n we recommend processing and selling of u. dioica leaf as a highly functional and nutritive food .", "role": "user" }, { "content": "stinging nettle ( urtica dioica l. ) has a long history of usage and is currently receiving attention as a source of fiber and alternative medicine . in many cultures , \n nettle is also eaten as a leafy vegetable . in this study , we focused on nettle yield ( edible portion ) and processing effects on nutritive and dietary properties . \n actively growing shoots were harvested from field plots and leaves separated from stems . \n leaf portions ( 200 g ) were washed and processed by blanching ( 1 min at 9698c ) or cooking ( 7 min at 98 - 99c ) with or without salt ( 5 gl1 ) . \n samples were cooled immediately after cooking and kept in frozen storage before analysis . \n proximate composition , mineral , amino acid , and vitamin contents were determined , and nutritive value was estimated based on 100 g serving portions in a 2000 calorie diet . \n results show that processed nettle can supply 90%100% of vitamin a ( including vitamin a as -carotene ) and is a good source of dietary calcium , iron , and protein . \n we recommend fresh or processed nettle as a high - protein , low - calorie source of essential nutrients , minerals , and vitamins particularly in vegetarian , diabetic , or other specialized diets .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: abbot ice shelf is underlain by e - w rift basins created at 90 ma \n amundsen shelf shaped by subsidence , sedimentation , and passage of the ice sheet \n bellingshausen plate boundary is located near the base of continental slope and rise \n abbot ice shelf is underlain by e - w rift basins created at 90 ma \n amundsen shelf shaped by subsidence , sedimentation , and passage of the ice sheet \n bellingshausen plate boundary is located near the base of continental slope and rise \n the bellingshausen sea and amundsen sea continental margins of west antarctica ( figure 1 ) have developed in very different manners . \n the bellingshausen margin , east of 90w95w , was a convergent margin throughout much of the mesozoic with oceanic crust subducting beneath antarctica [ e.g. , suarez , 1976 ; pankhurst , 1982 ; leat et al . , \n segments of the antarctic - phoenix ridge have successively collided with the subduction zone , beginning near 85w and proceeding northeast along the antarctic peninsula [ herron and tucholke , 1976 ; barker , 1982 ] . as each section of the ridge axis reached the trench , both spreading and subduction ceased in that segment and the margin became passive . \n in contrast , the amundsen sea continental margin , west of 90w95w , is a rifted continental margin formed by continental rifting and the separation of zealandia ( chatham rise and the campbell plateau ) from antarctica beginning at about 90 ma [ e.g. , larter et al . , 2002 ; eagles et al . \n , 2004a , 2004bb ] . the difference in the origin of the two sectors is reflected in seafloor spreading magnetic anomalies that become younger away from the amundsen margin , while anomalies seaward of the bellingshausen margin become younger toward the margin ( figure 1 ) . \n bathymetric map of the antarctic continental margin in the region near the abbot ice shelf showing seafloor spreading magnetic anomalies and fracture zones . \n magnetic anomalies generated at the bellingshausen - pacific ridge following rifting between zealandia and antarctica are shown in white . \n magnetic anomalies generated at the now subducted antarctic - phoenix ridge are shown in black . \n fracture zones and marine magnetic anomaly correlations are from cande et al . and larter et al . \n bathymetry is from the international bathymetric chart of the southern oceans ( ibcso ) [ arndt et al . , \n the amundsen continental margin may also have been impacted by interactions between the antarctic plate and the bellingshausen plate , a region of seafloor extending from the ridge axis toward the antarctic margin which moved independently of the antarctic plate from 83 to 61 ma [ stock and molnar , 1987 ; cande et al . , \n suggestions for this boundary s location range from within the oceanic crust seaward of the margin to well up onto the amundsen continental shelf [ stock et al . , 1996 ; \n larter et al . , 2002 ; wobbe et al . , 2012 ; gohl et al . \n the abbot ice shelf extends for 450 km along the coast of west antarctica between 103w and 89w , straddling the boundary between the bellingshausen and amundsen continental margins ( figure 1 ) . \n . the eastern portion of the ice shelf opens onto the bellingshausen sea continental shelf between several small islands , while the western edge faces the amundsen sea embayment ( figure 1 ) . \n cochran et al . carried out an inversion of nasa operation icebridge airborne gravity data over the abbot ice shelf ( figure 2 ) for bathymetry and investigated the implications of their results for ocean / ice interactions and the stability of the ice shelf . here \n we will use the bathymetry obtained from the inversion , which indicates that the western half of the ice shelf overlies a fault - bounded extensional terrain , along with existing geophysical observations from the west antarctic margin , to investigate the structure of the amundsen sea continental margin and the location and nature of the southern boundary of the former bellingshausen plate . \n free - air gravity anomalies from operation icebridge flights over the abbot ice shelf plotted along flight lines . \n gravity anomalies in offshore areas are satellite - derived free - air anomalies from mcadoo and laxon contoured at 10 mgal intervals . \n black lines offshore show the location of bathymetry and gravity profiles shown in figures 5 and 8 . \n white lines show the location of bas and awi seismic lines [ larter et al . , 1999 ; \n nasa s operation icebridge ( oib ) program obtained 10 north - south , low - altitude airborne geophysical lines across the abbot ice shelf and an east - west line along the axis of the ice shelf during the 2009 oib antarctic campaign ( figure 2 ) . \n spacing between the north - south flights varied from 30 to 54 km with a mean separation of 39.2 km . \n 2002 ] , a variety of ice - penetrating radars [ leuschen , 2011 ] , and a sander airgrav gravimeter [ argyle et al . , \n a major advantage of the airgrav system over other airborne gravimeters is that it is able to collect high - quality data during draped flights [ studinger et al . , \n flights during oib surveys are flown at a nominal height of 1500 feet ( 457 m ) above the earth s surface . \n free - air gravity anomalies measured on oib flights over the abbot ice shelf are shown in map view in figure 2 . \n large positive gravity anomalies of up to 72 mgal are consistently found over thurston island . \n anomalies reach 77 mgal over dustin island , at the edge of the ice shelf immediately east of thurston island , and positive anomalies are found at the other islands ( sherman , johnson , and farwell ) flown over within the abbot . \n an east - west band of large positive anomalies with maximum amplitudes of 5080 mgal also extends along the king peninsula on the mainland . \n this band of positive gravity extends offshore into the ice shelf east of 98w with a reduced amplitude and dies out near 94e . \n the rest of the ice shelf is characterized by negative free - air anomalies , generally in the range of 15 to 35 mgal . southeast of thurston island , \n large negative anomalies of 55 to 60 mgal are found over the northern and central part of the ice shelf from 97w to 94.5w . \n cochran et al . undertook an inversion of the gravity data for bathymetry beneath the ice shelf in two dimensions along individual flight lines using geosoft gmsys software . \n laser altimeter and radar data obtained on the same flight as the gravity were used to define the surface and base of the ice . \n the bed was kept fixed where it is observed in the radar data , while the bathymetry in water - covered areas ( where the seafloor can not be imaged with radar ) was varied to obtain the best match to the observed gravity . \n we show profiles along two lines , one ( line 3 ) over the western portion of the ice shelf and one ( line 5 ) over its central portion , in figure 3 and all of the results in map form in figure 4 . \n airborne geophysical lines 3 and 5 from cochran et al . across abbot and cosgrove ice shelves . \n for each profile , the top panel shows the observed free - air gravity in red and the anomaly predicted by the inversion in blue . \n bottom panels show the observed upper and lower ice surfaces from laser altimeter and radar measurements , respectively , and the upper surface of the solid earth . where ice is grounded , the earth s surface is determined from radar measurements . where ice is floating , the bathymetry is determined from inversion of gravity anomalies . \n vertical red lines show where the profile crosses the line flown along the axis of the ice shelf ( figure 2 ) . the longitude of that location is noted . \n note that actual faults will be steeper than shown here because of the filter applied to the gravity data . \n the orange dashed line shows the results of filtering the bed imaged by radar beneath the king peninsula with a 9.8 km filter , which is the spatial equivalent of the 70 s filter applied to the gravity data . \n the dashed line in the top panel of each profile shows the gravity effect of moho relief when the shallow structure is assumed to be locally compensated . \n basins , faults , and the spatial extent of rifting under abbot and cosgrove ice shelves from inversion of operation icebridge gravity data . \n offshore marine bathymetry is from the international bathymetric chart of the southern oceans ( ibcso ) [ arndt et al . , 2013 ] contoured at 100 m intervals to 1500 and 250 \n heavy dashed black line shows the limit of rifting beneath abbot and cosgrove ice shelves . \n cross - hatched area shows the basin boundary zone separating exposed or lightly sedimented basement from a deep , thickly sedimented basin . \n black lines offshore show the location of bathymetry and gravity profiles shown in figures 5 and 8 and the location of bas and awi seismic lines [ larter et al . \n estimates for the uncertainty of two - dimensional inversions along flight lines , based on comparison with known bathymetry and crossings with other lines , range from 50 to 100 m depending on the distance from constraints [ e.g. , tinto and bell , 2011 ] . \n a three - dimensional gravity inversion , with sparse geologic constraints , for bathymetry beneath the larsen c ice shelf [ cochran and bell , 2012 ] was compared with seismic reflection data [ brisbourne et al . , \n 2014 ] at 87 sites and a standard error of 59.0 m was determined [ cochran et al . , 2014 ] . \n a simple bouguer slab calculation implies that each 100 m of sediment with density 2.2 g / cm will lead to a seafloor depth overestimate of 30 m. depths obtained from the inversion will lie between the actual seafloor and crystalline basement depths [ cochran et al . , \n . this will affect the modeled water depth , but not the shape of the basins or our interpretation of their tectonic origin . \n the inversion software adjusts a single surface , in this case the rock - water interface , to obtain the best possible match between the observed and calculated gravity anomalies . \n the gravity effect along the airplane trajectory of moho relief assuming local compensation of the two profiles in figure 3 is shown as a dashed line on the gravity panel of each line . \n the calculation assumes that an unloaded ( no ice ) crustal section at sea level has a thickness of 27 km . \n the relative narrowness of the individual basins , combined with the effects of upward continuation to the flight altitude , results in the gravity effect of moho relief beneath the basins merging into a very broad low anomaly reaching a maximum amplitude of 18 mgal over the cosgrove ice shelf on line 3 and 15 mgal over the southern abbot on line 5 . \n the very broad nature of the moho gravity effect means that the shape and amplitude of the gravity anomaly over the individual basins results primarily from the shallow structure and thus that the moho relief will have minimal effect on the bathymetry resulting from the inversion . \n also , extensive geophysical study of the east african rift system has shown that early stage continental rifts are not locally compensated . \n rather , the faults bounding these asymmetric rifts are listric , curving with depth to sole out in a ductile lower crust [ e.g. , rosendahl , 1987 ; morley et al . , 1992 ; \n lambiase and bosworth , 1995 ; karner et al . , 2000 ] . as a result , crustal extension and thinning \n is spread over an area extending beyond the surface rift basin resulting in a broader and lower moho signal than shown in figure 3 . \n the bathymetry beneath the ice shelf to the west of 98w ( figure 3 , line 3 ) , determined from inversion of the oib gravity data , consists of a series of east - west trending basins . \n these basins are asymmetric with a steep slope bounding one side and we interpret them as fault - bounded half grabens ( figures 3 and 4 ) . \n our interpretation of an extended terrain beneath the abbot ice shelf is supported by the observation that the oib airborne radar images a deep , asymmetric basin under the king peninsula that appears fault bounded on the north and takes the form of a half graben ( figure 3 , line 3 ) . \n the northern wall of that basin is steeper than the walls of the gravity - delineated basins , but the gravity - determined slopes are reduced as a result of the 70 s filter applied to the gravity data . if we filter the radar - determined bed with the spatial equivalent of the gravity filter , the basin on the king peninsula has slopes very similar to those in the basins identified from the gravity inversion ( figure 3 , line 3 ) . \n the southern margin of thurston island is bounded by an en echelon set of faults . in the western portion of the ice shelf , \n the structure takes the form of a series of south - facing half grabens forming 1020 km wide topographic basins . \n this pattern continues south across the king peninsula to the cosgrove ice shelf , which also appears to be underlain by a half graben ( figure 3 , line 3 ) . east of about 98 , the tectonic pattern under the ice shelf changes to a broad 1200 m deep basin bounded by inward - facing faults ( figure 3 , line 5 ) . \n shallower small , fault - bounded basins are located along the southern margin of the ice shelf . \n the footwalls of the faults bounding these basins on the north form linear ridges associated with changes in ice thickness and/or create linear rows of ice rises and ice rumples on the ice shelf surface ( figure 3 , line 5 ) [ cochran et al . , \n extension in this area does not extend south of the abbot ice shelf as it does farther west . \n a possible alternative explanation for the basins beneath the abbot ice shelf is that they are erosional features carved out by an advancing ice sheet . \n broad , deep troughs have been imaged beneath many of the major ice streams of antarctica [ e.g. , ross et al . , 2012 ; wright et al . \n these troughs extend across the continental shelf seaward of the present edge of the ice sheet toward the shelf break [ e.g. , wellner et al . \n however , there are a number of observations that imply that the basins underlying the abbot and cosgrove ice shelves did not form in this manner . \n first , there are no significant ice streams feeding into either the abbot or cosgrove ice shelves [ swithinbank et al . , \n 2004 ] . also , the asymmetric shape of the basins is not typical of glacial troughs , but is diagnostic of tectonically formed half grabens . \n the asymmetric nature of the gravity - inferred basins is supported by the extremely asymmetric nature of the basin imaged by radar beneath the king peninsula ( figure 3 ) . \n in addition , the very linear nature of the e - w - trending sets of ice rises in the southern abbot between 98w and 94w is much more characteristic of tectonic activity than erosion . \n we interpret them as resulting from the impingement of the footwall rims of half graben basins onto the base of the ice shelf . \n in addition , these small closed basins are perpendicular to the flow of ice into the abbot ice shelf from the mainland and do not feed into the deeper main basin to the north , as they would if they were erosional features . \n our interpretation of the abbot basins as formed by rifting is also supported the presence of east - west oriented intrusive dikes on southern thurston island [ e.g. , storey et al . \n , 1991 ; leat et al . , 1993 ] , implying north - south extension . \n the last known igneous event on thurston island was the emplacement of a suite of e - w trending , coast - parallel dikes [ e.g. , storey et al . , 1991 ; leat et al . , \n 1993 ] into 120155 ma plutonic rocks [ grunow et al . , 1991 ] and imply north - south regional extension during that time interval . \n rifting between zealandia and antarctica began shortly before 90 ma with north - south extension [ larter et al . \n the extensional terrain identified beneath the abbot ice shelf to the west of 94w thus appears to be a rift active at the time of that opening . \n the bathymetry inferred beneath the ice shelf on lines 9 and 10 , located east of 94w between johnson and farwell islands , is shallower with gentler slopes and shows no features suggesting an eastward continuation of the basins underlying the western portion of the ice shelf ( figure 4 ) [ cochran et al . , \n the abrupt eastern end of the rifted terrain beneath the ice shelf at 94w coincides with the change from a former subduction continental margin toward the east to a rifted continental margin toward the west . \n the 94w boundary of the rifted terrain is aligned with a prominent linear north - south - trending feature in the satellite gravity field . \n this offshore lineation extends from 61s to the continental margin [ mcadoo and marks , 1992 ; mcadoo and laxon , 1997 ] and separates northward - younging seafloor spreading magnetic anomalies created by the separation of zealandia and antarctica from southward - younging anomalies created at the now subducted phoenix - antarctic ridge [ e.g. , weissel et al . , 1977 ; mayes et al . \n , 1990 ; mccarron and larter , 1998 ; larter et al . , 2002 ] ( figure 1 ) . \n the southernmost portion of the lineation was named the bellingshausen gravity anomaly ( bga ) by gohl et al . \n prior to the rifting of zealandia off antarctica , the bga lineation was a portion of a cretaceous ridge - trench transform separating the charcot plate and the pacific plate [ eagles et al . \n , 2004a ] . rifting nucleated along the transform at about 90 ma , perhaps at an intratransform spreading center [ bird and naar , 1994 ] or by propagation of the charcot - pacific ridge across the transform . \n this rifting propagated westward , splitting chatham rise and campbell plateau off antarctica [ larter et al . \n the mid - cretaceous rift terrain beneath the present abbot ice shelf to the west of 94w implies that the rifting initially extended southward into the present antarctic continent . after a limited amount of extension south of thurston island , rifting centered north of the island where it led to lithospheric rupture and the establishment of a spreading center \n . the eastern boundary of rifting at 94w can be traced across the continental shelf north of the abbot ice shelf as a gradient in the free - air gravity anomalies from higher anomalies in the east to lower in the west ( figures 2 and 5a ) . \n figure 5a shows a simple model of a bathymetry and gravity profile on the continental shelf near 7130s . \n 2013 ] and the gravity anomalies are from mcadoo and laxon . the ibcso grid is based on shipboard measurements and is thus independent of the gravity data , which comes from satellite altimetry . \n sediment depth at the eastern end of the profile is constrained by faint basement \n reflectors identified on seismic line bas923 - 26 along the outer continental shelf ( location shown in figures 2 and 4 ) published by cunningham et al . . \n depth to crystalline basement in the model increases from 2.5 km in the east to a maximum of 6 km north of thurston island . \n this transition , centered near 94w , marks the boundary from the nonrifted , formerly subducting margin in the east to the rifted margin in the west . \n the 6 km depth to basement calculated to the west of the transition is within the range observed farther west under the amundsen sea embayment continental shelf [ gohl et al . \n ( a ) two - dimensional gravity model of a west - to - east bathymetry and free - air gravity profile on the continental shelf near 7124s . \n observed gravity anomalies are in red and model anomalies are in blue . assumed densities in g / cm are shown . \n the model illustrates that gravity anomalies on the shelf near 95w can be explained by a transition from relatively shallow basement in the east to deeper , rifted basement to the west . \n ( b ) two - dimensional gravity model of a west - to - east bathymetry and free - air gravity profile across the bga structure near 6934s . \n depth to the top of the crust was taken from bas seismic reflection profile bas923 - 24 [ cunningham et al . , \n the bas seismic profile is nearly coincident with our line ( figures 2 and 4 ) . \n [ 1997a ] obtained a very similar result from modeling a shipboard seismic and gravity profile across the bga . \n a characteristic feature of the amundsen sea embayment is that the inner shelf has exposed or lightly sedimented basement that deepens dramatically seaward across a zone ( shown as a cross - hatched area in figure 4 ) that is well defined by seismic [ lowe and anderson , 2002 ; graham et al . , 2009 ; gohl et al . \n the boundary is marked by a prominent scarp with 2 s twtt ( two - way travel time ) of relief on seismic line awi20100134/135 ( location shown in figures 2 and 4 ) [ gohl et al . \n , 2013b ] . the landward edge of the basin boundary zone from 113w to 107w at 7340s \n is aligned with the southern margin of the rift under cosgrove ice shelf ( figures 4 and 7 ) . \n this basin edge appears to mark the southern extent of the cretaceous rifting related to separation between antarctica and zealandia and formation of the continental margin . \n east of 107w , the basin boundary zone bends to north , and separates the slightly extended crust of the cosgrove and abbot rifts to the east from the more highly extended and subsided crust under the amundsen embayment continental shelf to the west ( figure 4 ) . \n this north - south portion of the shelf basin boundary zone must have served as an accommodation zone during rifting , bounding and connecting offset rift segments [ e.g. , bosworth , , ; burgess et al . , 1988 ; ebinger , , ] . \n the n - s offset in the boundary zone near 113w probably is another accommodation zone separating slightly offset segments of the original rift . \n multichannel seismic ( mcs ) reflection lines across the continental shelf of the embayment presented by gohl et al . \n [ 2013b ] show 4.5 s twtt of sediment beneath the central shelf decreasing to 3.5 s twtt near the shelf break . \n [ 2013b ] utilized velocity information from ocean bottom seismometer ( obs ) seismic refraction lines to construct a depth transect across the continental shelf at about 108w that shows basement at about 4.5 km below sea level near the shelf edge , increasing to a maximum of about 7 km beneath the central shelf before shallowing abruptly across the shelf basin boundary zone to outcrop in the inner shelf . \n the deep basin extends westward to at least 113w , where seismic line awi-20100139 ( location shown on figures 2 and 4 ) shows 4.5 s twtt of sediment [ gohl et al . \n continental shelf becomes narrower , perhaps reflecting less crustal extension . west of 118w , the shelf edge curves sharply to the south ( figure 1 ) and the continental shelf narrows to about 150 km wide west of 120w . \n the western boundary of the deep amundsen embayment shelf basin thus appears to be in that region between 113w and 120w . \n utilized seismic and gravity data to produce a map of moho depth under the amundsen sea embayment . \n their depth to moho is about 24 km to the east of 112w , decreasing to 23 km at about 115w and 22 km in the westernmost embayment with very little north - south variation landward of the shelf break along a given longitude . \n kalberg and gohl discuss a seismic refraction line ( awi-2010100 ) in the western amundsen embayment ( location shown in figures 2 and 4 ) that determined the depth to moho from the middle of the basin boundary zone onto the region of exposed basement and showed it to increase landward from 24 to 27 km , consistent with the gravity calculation of 22 km in the basin seaward of the seismically determined moho depths [ gohl et al . \n an average depth of 6 km to the top of the crystalline crust combined with the 2224 km depth to the moho implies a mean thickness of 1618 km for the crust beneath the amundsen embayment shelf basin . \n winberry and anandakrishnan and chaput et al . used receiver function analyses to determine crustal thicknesses of 2531 km beneath stations in the west antarctica rift system with a thinner crust of 1725 km beneath the ross sea and within narrow troughs . \n other published estimates of the crustal thickness onshore from the amundsen sea are based on gravity data and are in the range of 2430 km [ e.g. , block et al . , 2009 ; jordan et al . , 2010 ; bingham et al . , \n the gravity - based thickness estimates do not include a sediment layer . however , anandakrishnan and winberry report less than 300 m of sediment at the winberry and anandakrishnan stations , except at the bentley subglacial trench , where 550 150 m of sediment was noted . \n 1998 ] and gravity [ bell et al . , 1998 ; studinger et al . , \n 2001 ] techniques have also found patchy to thin ( < 300 m ) sediments through most of the west antarctic rift system with thicker ( > 1 km ) sediments in narrow ( 2035 km wide ) fault - bounded basins , which are often associated with the onset of ice streams . \n thus , the gravity calculations also appear to represent reasonable estimates of the crystalline crust thickness . \n assuming an initial crustal thickness of 27 km consistent both with those calculations and with the seismically determined thickness just landward of the shelf basin [ kalberg and gohl , 2014 ] , the extension parameter , [ mckenzie , 1978 ] , for the shelf basin varies from 1.5 to 1.7 . \n this is a relatively modest amount of thinning , similar to that determined by steckler et al . \n for the southern gulf of suez , a failed rift that was abandoned at a relatively early stage in the development of the red sea [ e.g. , garfunkel and bartov , 1977 ; lepichon and francheteau , 1978 ; cochran , 1983 ; bosworth and mcclay , 2001 ] . the width of extended crust is wider in the amundsen sea embayment and thus the total amount of extension is greater . \n the area of extended crust under the amundsen sea embayment shelf is presently about 250 km wide , so values of 1.51.7 imply that about 80100 km of extension has occurred in this region . \n if the prerift crustal thickness was greater , perhaps 35 km which has been inferred for the ellsworth and whitmore mountains [ studinger et al . , 2002 ; \n 2010 ] and for the portion of east antarctica between the transantarctic mountains and wilkes subglacial basin [ ferraccioli et al . , 2001 ] , becomes 1.952.2 , which is still modest compared to the thinning necessary for lithospheric rupture . \n reported a crustal thickness of 58 km beneath the northern red sea , where organized seafloor spreading is just beginning [ cochran , 2005 ] . \n seismic experiments on the adjacent arabian and nubian shields gave crustal thicknesses of 3244 km [ e.g. , makris et al . , 1983 ; mooney et al . , 1985 ; prodehl , 1985 ; gettings et al . , 1986 ] , \n after this initial episode of extension , rifting in the amundsen sea embayment jumped or centered to the north of the present shelf where the major episode of rifting and lithospheric rupture occurred . \n [ 2007 , 2013a ] defined ne - sw and wnw - ese trending sets of magnetic anomalies on the continental shelf that they ascribed to magmatism accompanying continental rifting and to activity along the southern boundary of the bellingshausen plate , respectively . however , mcs profiles [ gohl et al . \n , 2013b ] show no disturbance in the sediments , including immediately above the basement where it is visible , where the profiles pass over either set of magnetic anomalies . \n thus , it is unlikely that the magnetic anomalies result from tectonic events postdating the rifting . some of the magnetic anomalies may result from structures present in the prerift basement , a mesozoic magmatic arc complex related to the subduction zone that was north of zealandia at that time . \n similar amplitude magnetic anomalies , also subparallel to the margin , are observed along the antarctic peninsula [ renner et al . \n 2001 ] where they have been interpreted as arising from cretaceous - aged intrusions into the crust [ e.g. , ferraccioli et al . , 2006 ; \n , and eagles et al . [ 2009b ] all suggested that the west antarctic rift system ( wars ) might extend to the pacific at some location between the amundsen sea embayment and the antarctic peninsula . \n [ 2013a ] proposed that a zone of negative magnetic anomalies extending nne - ssw from 72s to 73.5s between 106w and 108w indicate the presence of a rift basin beneath the amundsen sea embayment formed between 50 and 30 ma as a branch of the wars . \n [ 2013b ] showed east - west seismic lines across the shelf to illustrate the proposed basin . \n the eastern boundary of the hypothesized basin is formed by the basin boundary zone that separates the extended and subsided crust of the continental shelf basin from the thicker , less extended crust of the abbot rift region ( figure 4 ) . \n on gohl et al.s [ 2013b ] seismic line awi-20100126a ( location shown on figures 2 and 4 ) , the deepest sediment unit ( ass-1 ) , which they assign a cretaceous age and consider to consist of the pre and syn - rift sediment sequence , is truncated against the flank of the basin boundary zone . \n reflectors within the overlying unit ( ass-2 ) , assigned a late cretaceous - oligocene age [ gohl et al . \n , 2013b ] , continue across the entire length of the profile and are not offset at the boundary zone . \n this implies that the relief of the basin boundary zone was created during rifting and that it was not reactivated by cenozoic wars faulting . \n [ 2013b ] show a consistent pattern of northward ( seaward ) dip on seismic reflectors throughout the amundsen sea embayment . \n the apparent shallowing of seismic reflectors used to define the western edge of their proposed wars basin begins where the seismic line used to define it ( awi-20100120/awi-20100120 - 121 [ gohl et al . \n , 2013b ] ) ( location shown on figures 2 and 4 ) changes course to run more to the southwest rather than east - west across the basin [ gohl et al . , \n this means that the line then runs diagonally updip on the northward - dipping reflectors , resulting in the shallowing interpreted indicating as the western rift boundary . \n mcs line awi-20100139 [ gohl et al . , 2013b ] near 113w ( location shown on figures 2 and 4 ) , to the west of the hypothesized basin , shows 4.5 s twtt of sediment , which is virtually identical to the thickness shown by lines within it . \n thus , it is difficult to identify or delineate a nne - ssw oriented wars rift basin beneath the amundsen sea embayment . \n bingham et al . used radar , gravity , and magnetic data to define a rifted basin 500600 km to the east of the amundsen sea embayment . \n this ferrigno rift appears a more likely continuation of the wars toward the continental margin in the bellingshausen sea , where it may have intersected with the subduction zone that was present to the west of the antarctic peninsula for much of the cenozoic [ e.g. , eagles et al . \n the ferrigno rift is a narrow ( 1030 km wide ) , deep basin ( maximum depth of 1500 m below sea level ) with well - defined , steeply dipping flanks [ bingham et al . , \n 2012 ] , which resembles other narrow rifted basins observed within the wars . in summary \n this rift formed the easternmost segment of the continental rifting that separated zealandia from antarctica . \n extension beneath the ice shelf is relatively minor as rifting centered north of thurston island early in the rift process . \n the abbot rift is bounded on the west by an extensive sedimentary basin beneath the continental shelf of the amundsen sea embayment that formed during the same cretaceous rifting . the abbot rift and the amundsen embayment shelf basin \n are separated by a well - defined boundary zone that must originally been a transfer or accommodation zone between rift segments . \n the amundsen embayment shelf basin crust underwent more extension than the crust beneath the abbot rift , but again the extension shifted north of the present shelf and proceeded to seafloor spreading by magnetic chron 34 ( 83 ma ) ( figure 1 ) . \n it appears that the both the abbot rift and the amundsen embayment continental shelf have been tectonically quiescent since the initiation of seafloor spreading . \n the main factors shaping the development of the shelf since 83 ma have been subsidence , sedimentation and the advance and retreat of the west antarctic ice sheet . \n the bellingshausen plate was a small tectonic plate that existed in the southeastern pacific ocean to the north of west antarctica between about 83 and 61 ma , when it was incorporated into the antarctic plate [ e.g. , stock and molnar , 1987 ; cande et al . , 1995 ; mcadoo and laxon , 1997 ; larter et al . , 2002 ; eagles et al . \n stock and molnar first proposed the existence of the bellingshausen plate to explain differing fracture zone trends on either side of the antipodes fracture zone on the pacific - antarctic ridge during the late cretaceous and earliest tertiary . \n cande et al . confirmed the necessity for an independent bellingshausen plate and were able to define magnetic chron 27 ( 61 ma ) as when it was incorporated into the antarctic plate during a major reorganization of the spreading system . \n although the existence of an independent bellingshausen plate during that time interval has been confirmed , only the northern and eastern boundaries have been well delineated . \n mcadoo and laxon identified an approximately north - south lineation in the ers-1 satellite gravity field near 94w that includes the bga as the eastern boundary of the bellingshausen plate . \n . suggest that a short north - south trending graben imaged on seismic reflection lines at 126.4w may be a portion of it . \n the location and nature of the southern boundary of the bellingshausen plate has remained uncertain and a subject of discussion . \n . suggest that the bellingshausen plate may have been entirely oceanic and thus have formed seaward of the continental margin after rifting between zealandia and antarctica . \n . modeled a very wide bellingshausen plate boundary zone along the antarctic margin , often extending from mid - shelf well out into the deep ocean . \n [ 2007 , 2013a ] and gohl postulated a distributed or shifting plate boundary on the continental shelf of the amundsen sea made up of several wnw - ese trending geophysical lineations including the abbot ice shelf and a rift beneath pine island glacier . \n the bga structure in the deep ocean north of the abbot ice shelf consists of a north - south trending high - low gravity couple with a maximum peak to peak amplitude of about 140 mgal ( figures 2 and 5b ) . \n seismic reflection and gravity data show that the gravity low overlies a sediment filled trough , which gravity modeling implies extends to a depth of 1113 km [ gohl et al . \n [ 1997a ] argue that the bga was the site of convergence between the bellingshausen and phoenix plates prior to both of those plates being incorporated into the antarctic plate . \n kinematic models based on reconstruction of seafloor spreading magnetic anomalies [ larter et al . , 2002 ; eagles et al . , 2004bb , 2004a ; wobbe et al . , \n 2012 ] also imply significant convergence across the bga structure and it is generally accepted as a portion of the eastern boundary of bellingshausen plate . \n the tectonic boundary beneath the abbot ice shelf at 94w between the rift basin to the west and unextended crust to the east is directly in line with the bga structure ( figure 4 ) . \n this conclusion is based on modeling of a bathymetry , seismic reflection and gravity line ( bas923 - 26 ) extending from about 97w to 94w at 7040s on the outermost continental shelf ( figures 2 and 4 ) . \n their model shows a trough with 1317 km of sediment beneath the continental shelf that they interpret as a continuation of the bga structure . \n however , the profile that they model intersects the shelf edge gravity high at both ends of their line ( figure 2 ) . \n the shelf edge gravity high is part of an edge effect gravity anomaly resulting from superposition of the shallow density contrast of water versus sediment / crust and the deeper contrast of mantle versus crust across the margin ( figure 6 ) . \n the shape and width of the anomaly can be affected by the steepness of the margin ( figure 6b ) , by the presence of thick sediments ( figure 6c ) or by tectonic structures such as the outer shelf basement high observed in portions of the amundsen embayment margin [ gohl et al . , \n however , a gravity high at the shelf edge paired with a gravity low on the continental rise is a ubiquitous feature of continental margins . \n the gravity and bathymetry profile at 7130s , shown in figure 5a is located south of the shelf edge gravity high . \n it shows a broad step in the gravity anomalies that can be modeled as a transition from the shallower basement of the former convergent margin in the east to deeper basement of the rifted margin in the west ( figure 5a ) . \n this boundary served as a transform fault while rifting was active in the abbot rift . \n the bga structure , which formed later as the result of compressive deformation , does not extend into the continental crust of the continental shelf . \n ( a ) the calculated gravity anomaly for a generic margin with a 50 km wide ocean - continent transition . \n ( b ) the effect of changing the width of the transition and ( c ) the effect of thick sediment beneath the continental shelf . \n a. tectonic synthesis of the amundsen embayment continental margin resulting from our analysis of bathymetry beneath the abbot ice shelf . \n subice bed from radar and bathymetry from inversion of gravity anomalies are shown along oib flights . \n rift basins beneath abbot and cosgrove ice shelves are shown in blue with faults in red . \n cross - hatched area on the continental shelf shows the transition or hinge zone from exposed or lightly sedimented basement on the landward side to a thickly sedimented basin under the outer shelf . \n hachured area north of the shelf edge shows the portion of the southern boundary of the bellingshausen plate that underwent diffuse extension and solid black line shows the convergent portion of the southern boundary . \n fracture zones and marine magnetic anomaly correlations are from cande et al . and larter et al . \n tectonic synthesis of the amundsen embayment continental margin in the context of regional gravity anomalies . \n gravity anomalies in offshore areas are satellite - derived free - air anomalies from mcadoo and laxon contoured at 20 mgal intervals . \n color scale for airborne and satellite gravity anomalies is shown on right . otherwise , as in figure 7a . \n the bga gravity low swings to the west near 70s and merges with the continental rise gravity low portion of the continental margin edge effect anomaly ( figures 2 and 7b ) which is deeper and better developed here than farther to the west ( figures 2 , 7b , and 8) . \n this well - developed gravity low extends wsw from 95w to 102w where there is an offset to the north in both the shelf edge ( figure 7a ) and in the continental margin gravity anomaly ( figure 7b ) . \n the margin from 95w to 102w has a steep continental slope and a narrow , poorly developed continental rise ( figure 8a ) . a seismic reflection line ( bas923 - 25 ) across the margin near 97w ( location shown in figures 2 and 4 ) shows intense deformation beneath the continental slope [ larter et al . , 1999 ] \n on this line , the basement deepens toward the margin and the sedimentary section includes a sequence that thickens toward the margin with diverging reflectors that larter et al . \n these sediments become highly contorted and then acoustically opaque approaching the margin [ larter et al . \n bathymetry and free - air gravity profiles across the amundsen sea continental margin at 9730w and at 105w . \n note the change between the two profiles in steepness of the continental slope and of the shelf edge gravity high . \n compressive deformation along the continental margin between 95w and 102w is consistent with kinematic reconstructions of the development of the region based on marine magnetic anomalies [ larter et al . \n , 2002 ; eagles et al . , 2004a ] which imply a component of clockwise rotation between the bellingshausen and antarctic plates from about 74 to 62 ma , when the bellingshausen plate was absorbed into the antarctic plate . \n determined a bellingshausen / antarctica stage pole for the time interval between magnetic anomaly chrons 32n.1r and 28r ( 71.563.8 ma ) at 73.64s , 101.04w . \n this relative motion results in convergence along the eastern portion of the southern boundary of the bellingshausen plate with the antarctic plate and extension between the two plates to the west ( figure 9 ) . \n the transition in the relative motion between the two plates was located near 102w ( figure 9 ) . \n sketch showing plate interactions near the end of the bellingshausen plate s independent existence . the bellingshausen - antarctic pole for this time , at 73.64s , 101.04w [ larter et al . , \n motion between the two plates about this pole resulted in diffuse extension to the west of 102w in an area ( shown as hachured ) that includes the marie byrd seamounts . \n the relative motion to the east of 102 w was convergent with incipient subduction beneath the bellingshausen gravity anomaly structure , which forms the western side of a triangular salient of the antarctic plate ( see text ) . \n [ 2004a ] , we show a bellingshausen - phoenix ridge segment to the east of this salient with subduction of phoenix plate lithosphere along the continental margin to the east of 90w . \n the bga structure lies along the western side of what was at that time a triangular shaped salient of the antarctic plate ( figure 9 ) . \n this is the last remnant of the charcot plate , a small plate that separated from the phoenix plate in the mid - cretaceous [ mccarron and larter , 1998 ; larter et al . \n , 2002 ] , probably in a manner similar to the segmentation of the farallon plate into the rivera , cocos , and nazca plates [ e.g. , menard , 1978 ; atwater , 1989 ; lonsdale , 2005 ] . \n charcot plate lithosphere was subducted beneath antarctica until about the time of magnetic chron 34 ( 83 ma ) , when subduction stalled during the breakup of zealandia and antarctica , with the remaining fragment captured by antarctica [ larter et al . , \n 2004a ] in showing a bellingshausen - phoenix ridge segment to the east of the charcot salient . \n the triple junction at the western end of that segment migrated along the transform toward and probably into the subduction zone in response to the creation of bellingshausen lithosphere to the north . \n the character of the continental margin changes at 102w , where larter et al.s rotation pole predicts a change from compression to the east to extension to the west . \n the continental slope to the west of 102w is gentler than to the east with a broader , well - developed rise ( figure 8b ) . \n the difference in morphology is reflected in the shelf edge gravity high , which has a sharper seaward slope to the east of 102w than to the west ( figure 8) . \n seismic lines crossing the slope and rise to the west of 103w [ cunningham et al . \n 2013b ; kalberg and gohl , 2014 ; uenzelmann - neben and gohl , 2014 ] show no signs of the compression and intense deformation evident at 97w . \n extension to the west of 102w appears to have been diffuse and to have occurred in the area of the marie byrd seamounts . \n the marie byrd seamounts extend for 800 km from about 112w to 130w in an east - west band between 68s and 71s . \n alkali basalts dredged from hubert miller seamount ( 6917s , 12120w ) , haxby seamount ( 6907s , 12335w ) , and seamount c ( 6912s , 11730w ) gave ar / ar ages of 6556 ma [ kipf et al . , 2014 ] , during and slightly after the last stages of independent bellingshausen plate motion . \n proposed , on the basis of a himu component in the rocks recovered from the marie byrd seamounts , that the lavas erupted at the marie byrd seamounts are derived from cretaceous plume material underplating the west antarctica lithosphere that was transported by continental insolation flow [ king and anderson , , ] into the upper mantle of the adjacent oceanic areas . \n whatever the source of the lava , lithospheric extension is required to cause it to ascend and be erupted . \n we suggest that this extension resulted from rotation of the bellingshausen plate relative to the antarctic plate with diffuse extension through the region occupied by the marie byrd seamounts . \n seismic reflection lines through the seamounts [ gohl et al . , 1997b ; nitsche , 1998 ; uenzelmann - neben and gohl , 2012 ] show very rough basement and contorted sediments , described by gohl et al . \n seafloor spreading anomalies are not recognized in the region of the marie byrd seamounts ( figures 7a and 7b ) , even though they are found on the conjugate margin and presumably were originally present . \n we interpret this disruption as resulting from extension and the resulting volcanism between the bellingshausen and antarctic plates across a broad , diffuse plate boundary ( figures 7 and 9 ) . \n extension decreased to the east as the diffuse plate boundary approached the pole ( figure 9 ) , so that magmatism was eventually cut off at the eastern end of the marie byrd seamounts near 112w . \n inversion of nasa operation icebridge gravity data shows that the portion of the abbot ice shelf to the west of 94w is underlain by an extensional rifted terrain formed at about 90 ma in the early stages of rifting between antarctica and zealandia . \n a rift also underlies cosgrove ice shelf to the south . after a limited amount of extension south of thurston island , rifting centered north of the island where it led to lithospheric rupture and the establishment of a spreading center . \n the amundsen sea embayment continental shelf is underlain by a sedimentary basin , also formed by rifting between zealandia and antarctica . \n the crustal extension factor , , is 1.51.7 implying that 80100 km of extension occurred in a region that is now 250 km wide . following this extension , \n rifting shifted to a location north of the present shelf edge and proceeded to continental rupture and seafloor spreading . \n we interpret geophysical data from the region to show that , since that time , the amundsen embayment shelf has been tectonically quiescent and has not been affected by bellingshausen - antarctic interactions or by the west antarctic rift system . \n the main factors controlling the geologic development of the amundsen continental shelf since the late cretaceous appear to be subsidence , sedimentation and the advance and retreat of the west antarctic ice sheet . \n the southern boundary of the former bellingshausen plate is located at the base of the continental slope from 94w to 102w and is marked by a zone of compression of the sediments underlying the slope . west of 102w , the boundary swings away from the continental margin and becomes a diffuse zone of extension and magmatic activity encompassing the marie byrd seamounts . \n these seamounts extend for 800 km from about 112w to 130w in an east - west band between 68s and 71s . \n basalts recovered from three of the seamounts have been dated as erupted between 65 and 56 ma [ kipf et al . ,", "role": "user" }, { "content": "inversion of nasa operation icebridge airborne gravity over the abbot ice shelf in west antarctica for subice bathymetry defines an extensional terrain made up of east - west trending rift basins formed during the early stages of antarctica / zealandia rifting . \n extension is minor , as rifting jumped north of thurston island early in the rifting process . \n the amundsen sea embayment continental shelf west of the rifted terrain is underlain by a deeper , more extensive sedimentary basin also formed during rifting between antarctica and zealandia . \n a well - defined boundary zone separates the mildly extended abbot extensional terrain from the deeper amundsen embayment shelf basin . \n the shelf basin has an extension factor , , of 1.51.7 with 80100 km of extension occurring across an area now 250 km wide . \n following this extension , rifting centered north of the present shelf edge and proceeded to continental rupture . \n since then , the amundsen embayment continental shelf appears to have been tectonically quiescent and shaped by subsidence , sedimentation , and the advance and retreat of the west antarctic ice sheet . \n the bellingshausen plate was located seaward of the amundsen sea margin prior to incorporation into the antarctic plate at about 62 ma . during the latter part of its independent existence , \n bellingshausen plate motion had a clockwise rotational component relative to antarctica producing convergence across the north - south trending bellingshausen gravity anomaly structure at 94w and compressive deformation on the continental slope between 94w and 102w . \n farther west , the relative motion was extensional along an east - west trending zone occupied by the marie byrd seamounts.key points : abbot ice shelf is underlain by e - w rift basins created at 90 ma \n amundsen shelf shaped by subsidence , sedimentation , and passage of the ice sheet \n bellingshausen plate boundary is located near the base of continental slope and rise", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: it is commonly referred to as sore throat , although this term is often used imprecisely and is poorly defined . \n hence , whilst sore throat may be the symptom described by the patient , examination might also reveal nasopharyngitis ( that is , including the nasopharyngeal mucosa ) . \n the exact site of the irritation / inflammation is often not identified , with some studies relying on a patient - reported diagnosis ( that is , \n the following review will focus on sore throat as the primary symptom , which implies reported irritation and pain caused by inflammation and/or irritation of the oro ( medium part ) and hypopharynx ( lower part of the pharynx ) . as mentioned , there exist also overlapping symptoms to nasopharyngitis ( upper part of the pharynx ) but rhinitis or rhinosinusitis are usually diagnosed in those patients and sore throat is not the primary symptom . \n sore throat may have an infectious or non - infectious aetiology , although these sometimes overlap . \n most cases are infectious , with a large proportion ( up to 40 % ) caused by rhinovirus and adenovirus . \n other viruses including coronavirus , influenza , parainfluenza , epstein barr , and herpes simplex have also been implicated . of the bacterial sore throats , \n group a -haemolytic streptococcus is most frequently ( 536 % ) isolated [ 1 , 2 ] . other organisms to which sore throat has been attributed include mycoplasma pneumonia and arcanobacterium haemolyticus . rarely , candidal infections and other fungi and parasites have also been observed . \n a proportion of sore throats have non - infectious aetiologies , although the relative prevalence versus infectious cases is not well documented . \n the non - infectious causes of sore throat are extremely varied , and include physico - chemical factors ( for example smoking , snoring , shouting , drugs ) and environmental factors ( for example pollution , temperature , humidity / air conditioning ) . \n an approximation might be obtained by identifying people with sore throat in the absence of any other symptom ( e.g. rhinosinusitis ) or with persistent sore throat ( fig . \n 1 ) ; but this does not definitively exclude a viral , bacterial , or fungal cause . \n in fact , quantifying the prevalence of non - infectious sore throat would likely require the active identification and exclusion of all potential infectious causes.fig . \n 1schematic representation of typical course of sore throat of infectious and non - infectious aetiology schematic representation of typical course of sore throat of infectious and non - infectious aetiology overall , sore throat is a very common complaint and a frequent reason for seeking medical care . of 15,788 respondents ( aged 14 years or older ) in a scottish postal survey , 31 % reported they had experienced severe sore throat or tonsillitis in the previous year . in the usa , acute pharyngitis accounts for 12 % of all visits to outpatient departments , physician offices , and emergency departments . \n many people do not seek medical care when they have a sore throat , although geographical variation is considerable , dependent on social factors , access to and cost of healthcare , and attitudes to antibiotic prescribing . \n when patients with sore throat do present to primary care , the optimal management is controversial . \n furthermore , whilst antibiotics may provide only modest absolute benefits , there are few other prescription options available for sore throat . \n recurrent severe episodes of sore throat might indicate tonsillectomy , while concurrent severe symptoms such as difficulty breathing or swallowing usually require hospital admission . the main cause for concern \n though is the risk of rheumatic fever and suppurative complications in patients with group a -haemolytic streptococcus and for this reason many doctors , particularly in the usa , exercise caution . \n other potential complications include post - viral olfactory dysfunction and anosmia ( which might be prevented by vaccination in the future ) . \n a review of guidelines found that recommended management strategies vary widely . in some countries sore throat \n is considered to be self - limiting and swabbing and antibiotics are not routine , whereas , others recommend microbiological investigation with subsequent antibiotics for confirmed streptococcal cases . \n non - steroidal anti - inflammatory drugs and paracetamol are recommended for symptomatic relief [ 2 , 12 ] , while the relative risks and benefits of corticosteroids require further study [ 2 , 13 ] . \n the management of sore throat is , therefore , far from standardised or evidence based . \n it is clear then that the majority of people with sore throat have a benign self - limiting illness and many do not present for medical care . amongst these are a largely unquantified population with non - infectious aetiologies , about which little is understood and for whom the optimal treatment strategy is unclear . \n the objective of this review was to collate the information on non - infectious sore throat , particularly the proposed aetiologies and mechanisms involved . \n a wide variety of physico - chemical factors have been implicated in causing sore throat , including cigarette smoke inhalation , snoring , tracheal intubation , shouting , and concomitant illness or drug effects . \n smoking is a risk factor for sore throat , in both smokers themselves and in those exposed to secondary smoke ( passive smoking ) . \n cigarette smoking was significantly associated with sore throat / cough in us college students , and frequency of cigarette smoking and sore throat were correlated in japanese women . \n passive smoking was significantly associated with sore throat in 46 french non - smokers , 382 australian non - smoking indoor workers , and non - smoking australian nightclub and casino workers . \n furthermore , a questionnaire study reported a significant relationship between children s sore throats and maternal smoking . \n snoring is frequently associated with sore throat , and the two have risk factors such as smoking in common , although the direction of causality is not always clear . \n a high frequency of sore throat is a risk factor for habitual snoring in children and sore throat was reported by over half of those snoring children who were subsequently diagnosed with obstructive sleep apnoea . \n tracheal intubation and laryngeal mask airways are common causes of sore throat in people undergoing general anaesthesia [ 2427 ] . \n the reported incidence of postoperative sore throat varies widely , but is generally higher for tracheal intubation than for laryngeal mask airway . for patients undergoing tracheal intubation , \n an incidence of around 2845.5 % [ 27 , 29] and as high as 70 % has been reported . for laryngeal mask airway , the incidence is lower in the region of 3.521.4 % [ 27 , 29 , 31 ] . \n shouting and voice loading may cause sore throat , as reported by people in professions that require use ( and overuse ) of their voice for their work . \n for example , aerobics instructors have reported an increased incidence of sore throat unrelated to illness since beginning instructing and the frequency of aerobics classes has been shown to significantly correlate with sore throat symptoms in instructors . \n , sore throat can occur as a secondary consequence of functional dysphonia as well as vice versa . \n drug - induced sore throat is a notable adverse effect of some medications , including angiotensin - converting enzyme ( ace ) inhibitors and chemotherapy agents . \n sore throat is also a common problem in asthmatics taking inhaled corticosteroids [ 3739 ] , although these data may be in part confounded by a potential steroid - induced increased susceptibility to infection , including mycoses . \n in fact , people taking a wide variety of other drugs frequently report sore throat as an adverse effect , but in many cases the symptom will be coincidental ( that is , probably infectious sore throat and at a similar rate to placebo ) . \n for example , kawasaki disease ( a mucocutaneous vasculitis ) typically causes pharyngitis in both adults and children . \n furthermore , chronic pharyngitis is a common manifestation of gastroesophageal reflux disorder , with this presentation now termed laryngopharyngeal reflux disorder . \n while in these cases the sore throat can be considered to be a direct manifestation of the underlying condition , other illnesses may be associated with sore throat due to a consequent increased predisposition to infection . \n this may be the case for the often cited link with thyroid disease , where 41 % of patients with newly diagnosed thyroiditis report sore throat as a first symptom . \n a wide variety of physico - chemical factors have been implicated in causing sore throat , including cigarette smoke inhalation , snoring , tracheal intubation , shouting , and concomitant illness or drug effects . \n smoking is a risk factor for sore throat , in both smokers themselves and in those exposed to secondary smoke ( passive smoking ) . \n cigarette smoking was significantly associated with sore throat / cough in us college students , and frequency of cigarette smoking and sore throat were correlated in japanese women . \n passive smoking was significantly associated with sore throat in 46 french non - smokers , 382 australian non - smoking indoor workers , and non - smoking australian nightclub and casino workers . \n furthermore , a questionnaire study reported a significant relationship between children s sore throats and maternal smoking . \n snoring is frequently associated with sore throat , and the two have risk factors such as smoking in common , although the direction of causality is not always clear . \n a high frequency of sore throat is a risk factor for habitual snoring in children and sore throat was reported by over half of those snoring children who were subsequently diagnosed with obstructive sleep apnoea . \n tracheal intubation and laryngeal mask airways are common causes of sore throat in people undergoing general anaesthesia [ 2427 ] . \n the reported incidence of postoperative sore throat varies widely , but is generally higher for tracheal intubation than for laryngeal mask airway . for patients undergoing tracheal intubation , \n an incidence of around 2845.5 % [ 27 , 29] and as high as 70 % has been reported . for laryngeal mask airway , the incidence is lower in the region of 3.521.4 % [ 27 , 29 , 31 ] . \n shouting and voice loading may cause sore throat , as reported by people in professions that require use ( and overuse ) of their voice for their work . \n for example , aerobics instructors have reported an increased incidence of sore throat unrelated to illness since beginning instructing and the frequency of aerobics classes has been shown to significantly correlate with sore throat symptoms in instructors . \n , sore throat can occur as a secondary consequence of functional dysphonia as well as vice versa . \n drug - induced sore throat is a notable adverse effect of some medications , including angiotensin - converting enzyme ( ace ) inhibitors and chemotherapy agents . \n sore throat is also a common problem in asthmatics taking inhaled corticosteroids [ 3739 ] , although these data may be in part confounded by a potential steroid - induced increased susceptibility to infection , including mycoses . \n in fact , people taking a wide variety of other drugs frequently report sore throat as an adverse effect , but in many cases the symptom will be coincidental ( that is , probably infectious sore throat and at a similar rate to placebo ) . \n for example , kawasaki disease ( a mucocutaneous vasculitis ) typically causes pharyngitis in both adults and children . \n furthermore , chronic pharyngitis is a common manifestation of gastroesophageal reflux disorder , with this presentation now termed laryngopharyngeal reflux disorder . \n while in these cases the sore throat can be considered to be a direct manifestation of the underlying condition , other illnesses may be associated with sore throat due to a consequent increased predisposition to infection . \n this may be the case for the often cited link with thyroid disease , where 41 % of patients with newly diagnosed thyroiditis report sore throat as a first symptom . \n a wide variety of environmental factors have been cited as causes of sore throat , including general air pollution , specific pollution related to occupation , hazard , or industry , and pollution encountered in indoor environments . however , because the data are often epidemiological and individual pollutants are rarely emitted in isolation , it is not always possible to identify the precise cause of symptoms . \n patients with allergic rhinitis as well as those with postnasal drip , non - allergic rhinitis , and persistent cough may also experience sore throat as a secondary symptom . \n urban living and traffic fumes are frequently associated with sore throat . in children in hong kong , \n sore throat decreased when fuel sulphur levels were reduced , whilst exposure to vehicle emissions was linked with throat pain and chronic pharyngitis in shanghai bus drivers / conductors / taxi drivers and lack of air conditioning with frequent sore throat in hong kong bus and tram drivers . \n nitrogen dioxide has also been implicated [ 48 , 49 ] , as well as photochemical oxidants such as ozone ( o3 ) [ 50 , 51 ] \n . occupational or hazard - associated irritants that have been reported to cause sore throat include particulates , fumes , chemicals , and odours . \n particulates and fumes from a wide variety of industries have been implicated in sore throat , including pulp mills , woodworking , cement works , brick kilns , and factory exhaust emissions . \n the burning of gas creates multiple pollutants , including nitrogen oxides , particulates , and volatile organic compounds , and gas - related pollution has been linked with sore throat in several studies [ 58 , 59 ] . \n cooking and fires are important sources of pollutants worldwide , and in us non - smoking women , each hour of fireplace use was associated with ( little but measurable ) increased episodes of sore throat ( relative risk 1.04 ; 95 % ci 1.001.08 ) . \n a variety of chemicals have been reported to cause sore throat including organic screen - printing solvents , boron oxide , boron acid , and borax dust [ 63 , 64 ] , fluorinated hydrocarbons , machining coolants in the metal working industry , nitrogen trichloride from indoor swimming pools , chemical odours , and crude oil spills [ 6971 ] . in the newspaper printing industry which uses multiple chemicals including organic solvents , filler materials , and inks a higher than expected incidence of chronic pharyngitis has been reported . \n sore throat is also a frequently - reported ( 72 % ) symptom in people with multiple chemical sensitivity syndrome . \n the us world trade center disaster ( 9/11 ) resulted in uncharacterised hazardous exposures that are thought to be the cause of the upper airway inflammation seen in many of those exposed . in 10,378 fire fighters , \n sore throat was rare before the disaster ( 3.2 % reported frequent sore throat ) , but was the most common respiratory symptom in the year afterwards ( 62.4 % ) , declining and plateauing thereafter ( 36 % in 2 years , and 37 % in 4 years ) . along with cough , sore throat was considered to be the most sensitive initial indicator of respiratory insult . \n volcano eruptions emit sulphur dioxide and other gasses that may react with atmospheric components , and have been reported to cause sore throat . \n for example , sore / dry throat was significantly associated with volcanogenic sulphur dioxide and fine sulphate particles in hawaii [ 7678 ] , and the hourly incidence of sore throat showed clear exposure response relationships with post - eruptive so2 concentrations . \n complaints of sore throat are frequent in communities with confined animal facilities , wastewater treatment plants , and biosolids recycling operations . \n sore throat was also significantly more prevalent in greek solid waste collectors versus other workers . \n pig farming may be a particular cause of sore throat in nearby residents , with a 10 eu / mg increase in endotoxin being associated with increased log odds ( 0.10 0.05 ) of sore throat . \n farmers are additionally exposed to pesticides , and this was attributed as the cause of pharyngitis in a study of farmers versus other workers in the united arab emirates . \n these studies reveal that occupational and hazard - associated irritants , including particulates , chemicals , fumes and gasses , and endotoxin are well - documented causes of sore throat . \n indoor air pollution causes sick building syndrome , including sore throat . in the building assessment survey and evaluation ( base ) study , 7.1 % of workers in 41 large office buildings reported sore or dry throat . \n the underlying source of pollutants is thought to be poorly maintained moisture - related heating , ventilating , and air - conditioning components such as cooling coils and humidification systems . \n thus , symptom prevalence is higher in buildings ventilated mechanically or with air - conditioning compared with naturally ventilated buildings [ 87 , 88 ] . \n ozone brought into the building through the ventilation system , and its interaction with ventilation filters , has been implicated , as have particulates . damp and mouldy buildings also cause sore throats [ 92 , 93 ] . temperature and humidity affect mucus membranes , and have been linked with sore throat symptoms . \n heated air causes nasal pain and working regularly in a cold environment causes rhinitis and sore throat as well as changes in lung function . \n humidity is also important , with the overall intensity of sick building syndrome symptoms increasing when indoor air is not humidified . \n experimentally , cold dry air induces nasal inflammation [ 97 , 98 ] , and causes more nasal pain than humidified dry air . \n however , a population - based study showed that both cold temperature and low humidity appear to independently increase the risk of sore throat . \n there has been little systematic assessment of treatments for sore throat of non - infectious aetiology , and the field is hampered by a lack of objective outcomes , with most studies relying on subjective ( self - reported ) endpoints . by definition , \n a population with sore throat secondary to functional dysphonia might better reflect the non - infectious aetiologies , but such studies are few . \n many of the current data are unreliable for determining the efficacy of treatments for non - infectious sore throat , although some parallels can be drawn . \n it is likely that the efficacy of non - antibiotic treatments that has been reported in acute ( mostly infectious ) sore throat might also be seen in non - infectious sore throat . \n this extrapolation is based on the assumption that simple analgesia and anti - inflammatory effects are likely to be effective whatever the aetiology , especially if neurogenic inflammation is involved ( see below ) . \n a systematic review in acute sore throat found that treatments effective on early outcomes ( < 24 h ) included steroids , non - steroidal anti - inflammatory drugs ( nsaids ) , caffeine , and paracetamol , while paracetamol and nsaids also had a benefit on later ( > 24 h ) outcomes . \n flurbiprofen has been shown to be effective , as have chinese herbs used in combination with acupuncture ; chinese herbs have been the subject of a systematic review . \n inhaled natural ether oils have also been used , although the composition is mostly unknown . a russian study of 22 patients with aggravated chronic subatrophic pharyngitis against a background of acute respiratory viral infection showed that amylmetacresol / dichlorobenzyl alcohol lozenges ( strepsils , reckitt benckiser healthcare ltd ) resulted in a marked and durable reduction in pain symptoms , which was reported immediately after the first dose , and resulted in average pain scores three times lower than the control group by day 8 . \n although the aetiology of sore throat in these patients is not always well defined , several treatments show promise for the management of persistent sore throat . \n nimesulide and flurbiprofen were both found to be effective in a randomised study of 60 patients with non - infectious acute inflammation of the upper respiratory tract . \n experimentally , paracetamol in combination with caffeine reduces the nasal tonic pain elicited by dry air provocation , and caffeine enhances and prolongs the analgesia compared with control , supporting a role for analgesics in non - infectious sore throat . \n patients with sore throat secondary to functional dysphonia may respond to treatment of the underlying cause with vocal hygiene , voice training , avoidance of irritants and allergens , and co - medications ( e.g. proton pump inhibitors , anti - allergic drugs ) . \n the most frequently studied non - infectious population is that of postoperative sore throat and owing to its high incidence , a great many studies have been conducted in this area . \n for example , postoperative sore throat can be prevented with inhaled fluticasone propionate , intravenous dexamethasone , and lidocaine . \n other remedies include ketamine gargle , topical nsaids including benzydamine , perioperative amylmetacresol / dichlorobenzyl alcohol lozenges ( strepsils ) , liquorice , and an azulene derivate from chamomile . \n these studies in defined populations with non - infectious sore throat add to the data obtained in studies of less well - defined acute and chronic sore throat . \n although there is currently a lack of rigorous trials of treatments for non - infectious sore throat , there are enough data to suggest there may be several effective strategies . \n the treatment of non - infectious sore throat could be improved if the mechanisms were fully understood . \n however , the underlying pathophysiology , and components such as individual disposition and potential receptors and their interaction with irritants , are not yet well characterised . to complicate matters , \n inflammation has also been implicated in non - infectious aetiologies , with inflammatory cells and mediators isolated from the upper respiratory tract ( for example [ 114 , 115 ] ) . mechanical trauma and injury \n is almost certainly the precipitating factor in postoperative sore throat , as supported by the preventive efficacy of some lubricants . \n the inflammatory response has been replicated in a swine model , with elevated interleukin ( il ) 6 and polymorphonuclear leukocytes found in tracheal lavage fluid . \n factors such as tracheal - tube size and cuff design have been implicated during intubation , and sore throat following the use of a laryngeal mask airway appears to be related to the technique of insertion and intracuff pressure . \n the problem is more common in older age groups , and is related to grade of difficulty of intubation , duration of surgery , and patient s position during surgery , with all factors probably reflecting an increased risk of trauma . \n the mechanism underlying sore throat in people with gastroesophageal reflux disorder is likely to be chemical , that is , due to refluxed gastric content , although indirect effects through vagal ( sensory ) mechanisms have also been implicated . in rhinitis , pharyngeal irritation has been attributed to the lymphoid hypertrophy and prominence of adenoidal and tonsillar tissue , which results from chronic allergic inflammation of the upper airway , and kinins generated in nasal secretions have been implicated . \n the mediators released after nasal challenge with allergens or cold dry air are remarkably similar , including histamine , leukotrienes , prostaglandin d2 , and tame - esterase . \n the mechanism of cold air - induced rhinitis is well - characterised , being associated with nasal mast cell activation and sensory nerve stimulation ( irritation ) that generates a cholinergic reflex leading to rhinorrhoea . \n it seems likely that the same mechanism may be responsible for cold - induced sore throat a useful experimental model ( see below ) . \n snoring is problematic in terms of identifying the mechanism because although sore throat may cause snoring , snoring may also cause sore throat . \n the mechanism is likely to be mechanical and similar to that seen with dry air ; sore throat is also associated with mouth breathing [ 7 , 22 ] , obviously due to drying out of the pharyngeal mucosa caused by unfiltered , unwarmed , non - humidified air passage . \n similarly , it may be physical stress on the pharynx that causes sore throat following shouting and voice loading . \n along with such mechanical mechanisms , emotional stress and stress - induced subjective factors may also play a role , perhaps in combination with muscle spasm . \n excessive tension of the ( para ) laryngeal musculature ( due to psychological and emotional factors , vocal misuse , or compensation for underlying problems such as infection ) may result in pain that could promote the persistence of lesions in the laryngeal and pharyngeal mucosa . \n the drugs that frequently ( 240 % ) cause sore throat or dry cough as a recognised adverse effect include ace inhibitors , which increase pro - inflammatory mediators such as kinins , substance p , and prostaglandins . for this unwanted drug effect genetic predisposition factors \n switching from ace inhibitors to angiotensine receptor blockers is the most accepted alternative to prevent elevated cytokines . \n the mechanism by which inhaled corticosteroids cause sore throat is less certain [ 37 , 39 ] . \n histologically , an inflammatory infiltrate has been reported in some patients and locally - deposited steroid is likely to be a factor . \n in contrast , oral steroids alleviate the pain of acute sore throat , probably due to their anti - inflammatory action ( because of the risk of side effects they are not a routine therapeutic option in the long term ) . \n these physico - chemical causes of sore throat , while not fully elucidated , at least have plausible putative mechanisms . \n the situation for many environmental insults is more complex . throughout the literature , the term \n irritants is used , but documented evidence of their identities or the mechanism by which they might irritate and inflame mucous membranes is scarce . \n for example , is it a physical interaction or do the irritants bind to receptors that trigger a deleterious response that manifests symptomatically as sore throat ? \n identification of such receptors would certainly go a long way to establishing the mechanism and providing a therapeutic target . \n it irritates the stratified squamous epithelium of the oropharyngeal mucosa causing damage and reduced mucociliary clearance , and impairs the immune response . \n nicotine binds to the nicotinic acetylcholine receptor on sensory neurons [ 129 , 130 ] , and this is one of the proposed mechanisms for irritation and pain caused by cigarette smoke . \n however , chronic pain and an acute analgesic effect of nicotine attenuated by desensitisation and/or upregulation of the receptor on chronic exposure have also been suggested . \n conversely , abstaining from smoking for even one week causes a significant increase in reports of sore throat ( p = 0.049 ) and other cold symptoms . \n furthermore , the reason for this unexpected observation might be rebound sensitisation of ( nicotinic acetylcholine ) receptors . \n ozone has an inflammatory effect on both the upper and lower respiratory tract , characterised by polymorph infiltration and release of pro - inflammatory cytokines [ 135137 ] , although the specifics relating to sore throat are less certain . \n the underlying mechanism is proposed to include a direct effect of ozone on respiratory tract cell membranes and fluid , with lipid ozonation products activating specific lipases , triggering the release of endogenous mediators of inflammation [ 138 , 139 ] such as prostaglandin e , il8 , thromboxane b2 and calcitonin gene - related peptide . \n for example , in the presence of metal catalysts and moist air , so2 forms sulphuric acid and ammonium sulphate . \n sore throat in response to chemical odours could be due to irritation by the odorants themselves or co - pollutants , or a learned aversion which is well - established for odorants . \n particulate matter , which contains both organic and inorganic constituents , is associated with airway inflammation , apoptosis , genotoxicity , and oxidative stress [ 141143 ] . \n cement dust induces atrophic and hypertrophic changes in nasal and pharyngeal mucosa and chronic exfoliative bronchitis in animal models . \n much of the extensive research in the particulates field has been conducted in vitro , but humans exposed to fuel oil ash have evidence of inflammation , with increased il8 and polymorphs in nasal lavage fluid . induced sputum studies of fire fighters 10 months after the world trade centre disaster found levels of neutrophils and eosinophils increased in relation to the intensity of dust exposure . \n neurogenic inflammation may be responsible for the airway response to particulate matter and other environmental irritants such as ozone or sulphur dioxide [ 145 , 146 ] . \n these ion channels are found on sensory nerve fibres as well as immune and non - immune cells in the respiratory tract , and their activation results in the release of neuropeptides , such as calcitonin gene - related peptide and substance p , that trigger inflammation . \n trp channels are normally involved in detection of the thermal , mechanical , and chemical stimuli that are essential for survival . activated and sensitised \n trp channels , particularly trpv1 and trpa1 , have been implicated in chronic airways diseases ( chronic obstructive pulmonary disease and asthma ) and the respiratory response to environmental irritants [ 148 , 149 ] . \n trpv1 is activated by the potent respiratory irritant capsaicin , but also by extracellular protons ( generated during tissue acidosis and ischaemia ) and heat , and is also directly sensitised by nicotine . \n trpa1 is activated by chlorine , reactive oxygen species , and noxious constituents of smoke and smog , as well as ginger and bradykinin . \n it appears that reactive respiratory irritants may activate trpa1 by covalent modification , with glutathione depletion perhaps prolonging the effect . \n the cumulative effect may result in a reduced threshold for trpa1 activation , such that even low levels of smog or indoor pollutants elicit a response . \n along with this direct activation of trp channels by irritants , the pain associated with inflammation may also be mediated by trp channels . \n hence , when pro - inflammatory mediators ( such as histamine , prostaglandins , cysteinyl leucotrienes , proteases , nerve growth factor , and bradykinin ) bind to their respective receptors on sensory neurons , this indirectly results in trp activation via the endogenous activating lipids produced by the phospholipase c and phospholipase a2 pathways . \n the field of trp channel research is rapidly expanding , as it becomes clear that these ion channels may be involved in a vast range of diseases and chronic pain situations . \n because pain can be the result of overly sensitised trp channels , it follows that trp desensitisation using agonists might provide relief . \n this is supported by animal models , where capsaicin desensitises the acute and inflammatory airway response to a variety of noxious stimuli . with the sensory role of trps in detecting a wide range of thermal , mechanical , and chemical stimuli , trp channel activation and sensitisation and the consequent triggering of inflammation potentially accounts for many of the aetiologies of non - infectious sore throat , providing the possibility of interactions of trp channels and targets for intervention . \n along with trpv1 and trpa1 , other possible mechanisms and targets for intervention include : the somatosensory trp channels , trpm8 , trpv2 and trpv4 ; acid - sensing ion channel in the airway , which detects acidity and toxic gasses ; and the neuronal nicotinic acetylcholine - receptor [ 129 , 130 ] . \n in order to fully elucidate the pathophysiology of non - infectious sore throat , as well as assess the efficacy of any potential treatments , models with defined conditions and objective endpoints are required . many of the currently available models are not specific for sore throat , and use subjective endpoints \n . since the sensation of pain is so subjective , asking patients to rate its severity can often be the most appropriate endpoint . \n models for the study of non - allergic rhinitis and cough , but not specifically sore throat , include challenge with methacholine , histamine , capsaicin , mechanical pressure , and citric acid [ 155 , 156 ] . \n the sore throat pain model [ 157 , 158 ] , by definition , provides specificity . \n however , it requires patients to rate their throat pain on a visual analogue rating scale and , as such , the endpoint is subjective . \n pharyngeal inflammation was induced in a rat model by applying capsaicin directly to the pharyngeal mucosa . \n intubation has been used to induce pharyngeal inflammation in a swine model and laryngeal inflammation in a rat model , with analysis of biomarkers . \n well - defined human models of pharyngeal irritation with objective endpoints are generally lacking . one that is in research use is the tonsilliopharyngeal assessment ( tpa ) scale which is based on a clinical examination of the throat , although this still depends on the clinician s judgement . currently , any correlation between subjective and objective endpoints is therefore untested . in humans , biomarkers , such as immune cells and inflammatory mediators , \n are often experimentally measured in epidemiological studies , providing an objective marker of airway inflammation . however , \n unless obtained from a biopsy ( which is too invasive for routine use ) , these are not necessarily specific to the pharyngeal mucosa . \n for example , analysis of bronchiolar lavage fluid reflects inflammation occurring in the lungs but is relatively invasive to perform , \n nasal lavage , which samples the upper respiratory tract , gets closer to the pharyngeal mucosa , but is still relatively specific to the nasal epithelium . \n nasal challenge with cold dry air has been used to experimentally replicate cold air - induced rhinitis [ 97 , 98 , 153 ] and can be combined with the objective analysis of biomarkers of nasal inflammation . \n the lack of suitable models for the study of non - infectious sore throat has hampered progress in elucidating mechanisms and identifying treatments . \n a new model has been developed using cold dry air ( cda ) to experimentally induce controlled inflammation in the pharynx of healthy volunteers . \n the inflammation is then quantified by measuring inflammatory mediators in pharyngeal lavage fluid [ unpublished ] . the model is a promising tool for future research because it induces reversible pharyngeal irritation , in controlled conditions , and is amenable to a crossover study design . \n it may provide a valuable research tool and an objective way of measuring the therapeutic potential of treatments . \n furthermore , this procedure may also allow for research in occupational and environmental medicine where exposure limits for single potential irritants exist but interactions are not yet well established . \n in this way , a cda stimulus may be combined with one or two potential irritants in order to generate comparable results in crossover study designs . \n despite how common non - infectious sore throat is , little is understood about how it is caused by such a wide variety of physico - chemical and environmental factors . \n it is possible that in many cases the cause of persistent non - infectious sore throat involves a combination of physico - chemical and environmental factors . \n inflammatory processes ( of various mechanisms , including neurogenic inflammation ) appear to underlie sore throat of non - infectious aetiologies , and in many cases this may be the source of the pain . \n inflammation also underlies infectious sore throat , so many of the therapeutic options may be also appropriate for non - infectious sore throat . indeed , \n although limited , the literature suggests that appropriate treatment options for non - infectious sore throat may include drug therapy . \n however , the lack of suitable human experimental models hampers the identification of drug therapy ( for example topical trp antagonists ) . \n a new model using cold dry air and pharyngeal lavage may provide a useful tool for the study of mechanisms including receptor interactions and treatment of non - infectious sore throat . \n this article is distributed under the terms of the creative commons attribution license which permits any use , distribution , and reproduction in any medium , provided the original author(s ) and the source are credited .", "role": "user" }, { "content": "objectives the aim of this review is to examine the causes , pathophysiology and experimental models of non - infectious pharyngitis ( sore throat).introductionthe causes of sore throat can be infectious ( viruses , bacteria , and fungi ) or non - infectious , although the relative proportion of each is not well documented.methodsa pubmed database search was performed for studies of non - infectious sore throat.results and conclusionsnon - infectious causes of sore throat include : physico - chemical factors , such as smoking , snoring , shouting , tracheal intubation , medications , or concomitant illness ; and environmental factors including indoor and outdoor air pollutants , temperature and humidity , and hazardous or occupational irritants . the pathophysiology underlying non - infectious sore throat is largely uncharacterised , although neurogenic inflammation looks to be a promising candidate . \n it is likely that there will be individual disposition factors or the coincidence of more than one irritant with possible up to now unknown interactions between them . \n therefore , experimental models with defined conditions and objective endpoints are needed . \n a new model using cold dry air to directly induce pharyngeal irritation in humans , with pharyngeal lavage to measure biomarkers , may provide a useful tool for the study of mechanisms and treatment of non - infectious sore throat .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: in nigeria , the abattoir industry is an important component of the livestock industry providing domestic meat supply to over 150 million people and employment opportunities for teaming population . \n facilities for the treatment of abattoir effluents are lacking , unlike in developed countries where these facilities are adequately provided . \n potential health risks from waterborne pathogens can exist in water contaminated by abattoir effluents , runoff from feedlots , dairy farms , grazed pastures [ 5 , 6 ] , fallow and sod amended with poultry litter , grassland treated with dairy manure , and sewage sludge treated land . \n such contamination of water bodies from abattoir wastes could constitute significant environmental and public health hazards [ 1013 ] . \n bacteria from abattoir waste discharged into water columns can subsequently be absorb to sediments , and when the bottom stream is disturbed , the sediment releases the bacteria back into the water columns presenting long - term health hazards . \n pathogens present in animal carcasses or shed in animal wastes may include rotaviruses , hepatitis e virus , salmonella spp . \n , cryptosporidium parvum , and giardia lamblia . the primary reservoir for e. coli o157 : \n h7 has been reported to be healthy cattle in a study in canada , although this bacterium is also endemic to swine and sheep . \n these zoonotic pathogen can exceed millions to billions per gram of feces , and may infect humans through various routes such as contaminated air , contact with livestock animals or their waste products , swimming in water impacted by animal feces , exposure to potential vectors ( such as flies , mosquitoes , water fowl , and rodents ) , or consumption of food or water contaminated by animal wastes [ 17 , 18 ] . \n the consequences of infection by pathogens originating from animal wastes can range from temporary morbidity to mortality , especially in high - risk individuals . due to the difficulties in quantifying pathogens , indicators of fecal pollution , including coliform bacteria , fecal coliforms , e. coli , and/or enterococci \n epidemiological evidence supports the relationship between the fecal indicator bacteria e. coli , enterococci , and the incidence of gastrointestinal illness following recreational water exposure and provides the basis for water quality regulations . in nigeria , \n abattoir wastes with large quantities of animal faeces are often channeled directly into water bodies , used for domestic purposes by human beings . in port harcourt area of nigeria \n , abattoir effluents are channeled directly without treatment into one of the tributaries of the river niger . \n the bacteriological characteristics of abattoir wastewater and its possible effect on receiving water bodies which is likely to cause pollution with intensified environmental and public health hazards has not been documented in abuja , nigeria . \n the objective of this study was therefore , to investigate the bacteriological characteristics of abattoir wastewater , to determine its strength , its relationship with receiving water bodies and possible public / environmental health hazards in abuja , nigeria . \n the results are based on mean concentrations of total colifrom ( tc ) , fecal coliform ( fc ) , fecal streptococcus , and escherichia coli in samples of abattoir wastewater , water servicing the abattoirs , and receiving water bodies collected at 5 major abattoirs in abuja . \n data on the usage of receiving water bodies and sources of water servicing the abattoirs were also obtained . \n results obtained could be helpful in defining future abattoir wastewater treatment and management practices in nigeria and elsewhere . \n samples and data were collected from five major abattoirs in abuja and water bodies receiving abattoir wastewater . \n abuja is the federal capital of nigeria with a population of about 1.857 million people and one of the fastest growing cities in the world . \n it is located in the north central part of nigeria , with coordinates of 940n 7290e and a total land area of 713 km(275.3 sq m ) . \n the 5 major abattoirs serving the city and its environs are the deidei , gwagwalada , karu , kubwa , and kuje abattoirs . \n animals slaughtered at the 5 major abattoirs include cattle , sheep , and goats , with average daily slaughter figures of 350 cattle , 450 sheep , and 670 goats . \n samples were collected from deidei , gwagwalada , karu , kubwa , and kuje abattoirs between the months of january and august 2011 . \n the abattoirs were visited at 4 days interval ( every market day of the area ) to collect samples . \n a total of 60 samples were collected from each of the abattoirs during the period . \n samples were collected in the morning during the peak activities between 08.00 am and 09.00 am using the grab sampling method with a wide mouthed 500 ml sterilized pyrex glass bottles with tight screw dust proof stoppers . \n wastewater samples were collected at the abattoirs from a point where it is thoroughly mixed and close to the discharging point ( outlet ) 100 mm below the surface , samples from receiving water bodies were collected 100 m upstream and downstream ( before and after mixing with the abattoir wastewater ) , respectively . \n extracts from these samples were first diluted in peptone water 01% ; 10 ml of the sample were added to 90 ml of the diluents , producing a dilution of 10 . \n successive decimal dilutions were obtained , and then prepared for the analyses of tc , fc , e. coli , and f. streptococcus using the multiple - tube most probable number ( mpn ) fermentation technique . \n the presumptive , confirmed and completed tests were carried out as described in the standard methods for the examination of water and wastewater , american public health association . \n the numbers of positive findings were enumerated and statistical tables ( mpn tables ) were used to determine bacteria counts . a well structured questionnaire was orally administered to obtain data on the water servicing the abattoirs and the usage of water bodies receiving abattoir wastewater . the distance from abattoir wastewater outlet to water bodies and the point of usage of the receiving water bodies \n the mean value concentrations of tc , fc , f. streptococcus , and e. coli ( mpn/100 ml ) for abattoir wastewater , water servicing the abattoirs , and water bodies receiving abattoir wastewater were determined . \n microbial concentrations of the abattoir wastewater , water servicing the abattoirs , upstream and downstream water bodies receiving abattoir wastewater were compared ( p < 0.05 ) to establish if there is any relationship . \n the tc counts of the abattoir wastewater were also compared with the federal environmental protection agency ( fepa ) recommended level for the discharge of industrial wastewater into surface water and land application in nigeria . \n water servicing the abattoirs were from borehole , well and stream water at deidei , karu , and kuje abattoirs while borehole and well water were used at gwagwalada and kubwa abattoirs . \n untreated abattoir wastewater was discharged directly into water bodies ( streams , rivers , and drainages ) that are used for drinking , bathing , washing of clothes , home utensils , watering animals , watering of crops , and other domestic purposes downstream at distances of 680 m at deidei , 415 m at gwagwlada , 610 m at karu , 542 m at kubwa , and 320 m at kuje area . \n tables 1to 5 present the mean values of tc , fc , f. streptococcus and e. coli ( mpn/100 ml ) of the abattoir wastewater , water servicing the abattoirs , water bodies receiving abattoir wastewater at 100 m upstream and downstream and the recommended tc count of industrial effluents ( wastewater ) limit for discharge into surface water and land application in nigeria . \n this study was conducted to determine the bacteriological characteristics of abattoir effluents discharged into water bodies and its possible health hazards on receiving water bodies in abuja , nigeria . \n the concentrations of tc , fc , f. streptococcus , and e. coli were determined in the abattoir effluents , water servicing the abattoir , and water bodies receiving abattoir effluents . \n bacterial concentrations ( mpn/100 ml ) of abattoir effluents ranged from 4.8 10 to 5.8 10/100 ml of tc , 8.2 10 to 3.2 10/100 ml of fc , 5.2 10 to 2.0 10/100 ml of f. streptococcus , and 1.2 10 to 2.0 10/100 ml of e. coli while receiving water bodies ranged from 6.2 10 to 1.4 10/100 ml of tc , 2.6 10 to 2.2 10/100 ml of fc , 1.2 10 to 1.2 10/100 ml of f. streptococcus , and 2.0 10 to 4.0 10/100 ml of e. coli 100 m upstream , and 6.6 10 to 6.0 10/100 ml of tc , 6.2 10 to 1.8 10/100 ml of fc , 1.8 10 to 6.0 10/100 ml of f. streptococcus , and 4.8 10 to 6.6 10/100 ml of e. coli 100 m downstream after mixing with the abattoir wastewater . \n bacterial counts of 4.8 10 to 1.2 10/100 ml of tc , 4.0 10 to 2.6 10/100 ml of fc , 1.8 10 to 2.1 10/100 ml of f. streptococcus , and 4.8 10 to 1.2 10/100 ml of e. coli were observed in the water sources servicing the abattoir ( tables 15 ) . \n tc bacteria concentration in the abattoir wastewater discharged exceeded the recommended limit for the discharge of effluents into water bodies and land application in nigeria . \n there was no significant difference ( p < 0.05 ) between the mean bacterial counts of abattoir wastewater and receiving water bodies 100 m downstream ; is an indication of contamination of receiving water bodies with abattoir wastewater , similar findings has been reported in other places [ 2 , 21 , 26 , 27 ] . \n the receiving water bodies were used for drinking , bathing , washing , watering of animals , watering of crops , and other domestic purpose downstream . \n fecal coliforms live in the digestive tract of warm - blooded animals ; their counts are often used as a surrogate measurement for gastro - enteric pathogens , since the presence of fecal coliform bacteria is an indication of contamination by human and/or animal wastes . \n e. coli is the most prevalent member of the fecal coliform group ; livestock harbour the bacteria and release it in their feces . and \n so the presence of e. coli in water is considered a specific indicator of fecal contamination and the presence of enteric pathogens;it is used as the general indicator organism that signals whether there has been fecal contamination or not . \n the high levels of total coliforms and e. coli in the abattoir wastewater and receiving water bodies are therefore an indication of the contamination of water sources with feacal material and possibly pathogenic organisms from abattoir wastewater discharged untreated ; similar findings have early been reported [ 27 ] . \n the discharge of untreated abattoir wastewater could result in out breaks of e. coli infection as observed by [ 2830 ] . \n bacterial pathogens such as salmonella , campylobacter , and listeria monocytogenes have been isolated from abattoir wastewater . \n the microbial concentrations observed upstream in this study could be as a result of indiscriminate disposal of domestic wastes into water bodies by human beings in these areas . \n this study observed that untreated abattoir wastewater discharged into water bodies in abuja , nigeria contains bacterial counts above the recommended level for discharge into water bodies in nigeria . receiving water bodies \n were contaminated with bacteria pathogens that could impact on public health , especially that streams and rivers still serves as major sources of water supply in developing countries like nigeria . \n the importance of adopting appropriate abattoir wastewater treatment measures to prevent the chances of contaminating water bodies and ground water in nigeria is therefore recommended .", "role": "user" }, { "content": "bacteriological characteristics of abattoir effluents ( wastewater ) , abattoir water source , and water bodies receiving abattoir wastewater were investigated in abuja , nigeria using the multiple - tube fermentation technique . \n source of water to the abattoirs and the usage of water bodies receiving abattoir effluents were determined using questionnaires . \n bacterial counts ranged from 4.8 106 to 5.8 105 /100 ml of total coliform ( tc ) , 8.2 104 to 3.2 104/100 ml of fecal coliform ( fc ) , 5.2 104 to 2.0 104/100 ml of fecal streptococcus and 1.2 104 to 2.0 103/100 ml of escherichia coli for abattoir effluents 6.6 105 to 6.0 105/100 ml of tc , 6.2 104 to 1.8 104/100 ml of fc , 1.8 104 to 6.0 103/100 ml of f. streptococcus , and 4.8 103 to 6.6 102/100 ml of e. coli for water bodies receiving abattoir effluents 100 m downstream . \n tc bacteria counts for abattoir effluents exceeded recommended limit for discharge into surface water in nigeria . \n no significant difference ( p < 0.05 ) was observed between bacterial counts of abattoir effluents and receiving water bodies 100 m downstream : an indication of contamination of receiving water bodies by abattoir effluents and possible public and environmental health hazards .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: after more than 30 years since its first clinical use , cisplatin is still one of the most widely used drugs in anticancer chemotherapy . \n the action mechanism of cisplatin has been explained in its essential aspects , relatively to its interaction with dna . \n nevertheless , some essential chemical processes , related to what happens before the cisplatin reaches the dna , generally considered its final target , are still to be identified . among these processes , \n the best known is the formation of aquospecies , the main reaction of activation of the drug [ 2 , 3 ] which occurs in the cytoplasmic compartment by hydrolysis of the chloride ligands . \n however , many other nongenomic biomolecules could be potential targets for platinum [ 4 , 5 ] . \n sulfur - rich biomolecules , including free amino acids ( cysteine and methionine ) , oligopeptides ( glutathione ) , and proteins represent good targets for a soft metal such as pt [ 69 ] . moreover , the need to improve the cisplatin clinical protocol drives much research into better understanding of its antitumor activity mechanism . on the other hand , in order to overcome acquired cellular resistance to cisplatin , much effort is currently devoted to the discovery of new pt anticancer drugs . in the last years \n several pt(ii ) and pt(iv ) complexes have been synthesised , but only a few compounds , such as carboplatin and oxaliplatin [ 1 , 11 ] , are actually used in clinical therapy . \n many studies [ 1214 ] , carried out by this research group [ 15 , 16 ] , aimed to understand not only the nuclear , but also the cytoplasmic events taking place in cisplatin - treated cells and able to induce apoptosis . \n this research group has long been involved in both the synthesis and preliminary evaluation of biological activity of the new pt complexes and in the subsequent studies of intracellular signal transduction , triggered by these molecules and by cisplatin itself [ 5 , 1719 ] . \n recently , this group has synthesized and studied new platinum(ii ) complexes containing acetylacetonate ( acac ) in the metal coordination sphere : [ ptcl(o , o-acac)(dmso ) ] ( 1a ) with only one oxygen - bonded chelate acac ( o , o-acac ) , [ pt(o , o-acac)(-acac)(dmso ) ] ( 2a ) containing both an o , o-acac and a -bonded acac ( -acac ) and their dimethylsulphide ( dms ) analogues ( 1b and 2b ) having the same key structures ( scheme 1 ) , that have shown interesting biological activities [ 2023 ] and in vitro antimetastatic activity . \n these compounds not only are able to induce apoptosis in endometrial cancer cells ( hela ) , with activity up to about 100 times higher than that of cisplatin , but also show high cytotoxicity in cisplatin - resistant breast cancer cell lines ( mcf-7 ) . \n the [ pt(o , o-acac)(-acac)(dms ) ] complex ( 2b ) with two acetylacetonate ligands , one o , o-chelate and the other one sigma - linked by methine in gamma position , is the more active among the tested complexes . as well as their specific biological activity , these complexes showed an interesting and selective chemical reactivity with nucleophiles with different hsab ( hard - soft acid - base ) character . indeed , in the complexes [ ptcl(o , o-acac)l ] ( l = dmso , dms ) , containing two ligands with different hard / soft character on the same metal , selective substitution reaction in the presence of further ligands was observed . \n the more hard ligand replaces the harder one , and the more soft replaces the softer one . \n however , in these complexes the replacement of cl with hard ligands is kinetically and thermodynamically less favoured with respect to the substitution reaction of dms or dmso with soft - type ligands . \n when only a soft ligand is present , as in the case of the complexes [ pt(o , o-acac)(-acac)l ] ( l = dmso , dms ) , the reaction takes place only in the presence of soft nucleophile , otherwise there is no reaction . \n these results , together with the biological studies , indicate that for these complexes , characterized by low reactivity with hard nucleophiles and specific reactivity with soft ligands , the dna could not be the main target . in this \n we reported the h nmr investigations on reactivity of the new compounds with hard and soft biological nucleophiles , such as nucleobases and sulfur amino acids , confirming selective reaction with the latter . in this work the well - known salmonella - his reversion test ( ames ' test , a standard reverse mutation assay on the mutagenic capability of the complexes ) on two salmonella typhimurium strains , ta98 and ta100 , was performed . \n the bacteria reversed mutation assay ( ames test ) , which is normally used to evaluate the mutagenic properties of test substrates , can be also used to assess the ability of tested compounds to interact with dna . \n h nmr spectra were recorded on a bruker avance dpx 400 , using cdcl3 , and d2o as solvent . \n h and c chemical shifts in cdcl3 were referred to tms , by using the residual protic solvent peaks as internal references . \n h and c chemical shifts in d2o were referenced to tsp ( 2,2,3,3-d(4)-3-(trimethyl - silyl)-propionic acid sodium salt ) , (h ) = 0 ppm , as an external reference . \n pt chemical shifts were referenced to na2[ptcl6 ] ( d(pt ) = 0 ppm ) in d2o as an external reference . \n [ ptcl2(dmso)2 ] and k[ptcl3(dmso ) ] were prepared according to previously reported procedures . \n a solution of acetylacetone ( 0.097 g , 0.973 mmol ) and koh ( 0.027 g , 0.487 mmol ) in methanol ( 5 ml ) was added dropwise to a solution of k[ptcl3(dmso ) ] ( 0.204 g , 0.487 mmol ) in water ( 10 ml ) at room temperature with stirring . after few minutes a yellow precipitate separated from the solution . \n the reaction mixture was left stirring overnight , and the pale yellow precipitate of [ ptcl(o , o-acac)(dmso ) ] ( 1a ) was then isolated by filtration and dried under vacuum ( yield 0.149 g , 75% ) . \n calcd for c7h13clo3spt ( 407.79 ) : c 20.62 , h 3.21 ; found c 20.73 , h 3.28 . alternatively , a solution containing acetylacetone ( 0.097 g , 0.966 mmol ) and koh ( 0.027 g , 0.483 mmol ) in water ( 5 ml ) was added dropwise to a suspension of cis-[ptcl2(dmso)2 ] ( 0.204 g , 0.483 mmol ) in water ( 10 ml ) at room temperature with stirring . \n the suspension was left under stirring for one day , and the solid was then filtered and dried under vacuum ( yield 0.027 g , 26% ) . \n h nmr in cdcl3 ( 298 k ) : 2.06s [ 3h , ch3(o , o-acac ) ] , 2.02s [ 3h , ch3(o , o-acac ) ] , 5.56s [ 1h , ch(o , o-acac ) ] , 3.44s [ 6h , ch3(dmso ) , jh - pt 40 hz ] . \n c nmr in cdcl3 ( 298 k ) : 26.3 [ 2c , ch3(o , o-acac ) ] , 102.3 [ 1c , ch(o , o-acac ) ] , 185.1 and 185.9 [ 2c , co(o , o-acac ) ] , 44.3 [ 2c , ch3(dmso ) ] . \n a solution of acetylacetone ( 0.358 g , 3.576 mmol ) and koh ( 0.114 g , 2.860 mmol ) in methanol ( 5 ml ) was added dropwise to a suspension of cis-[ptcl2(dmso)2 ] ( 0.302 g , 0.715 mmol ) in methanol ( 20 ml ) at room temperature with stirring . the reaction mixture slowly became a pale yellow solution . \n after one day , the solvent was evaporated under vacuum , and the yellow residue was extracted with chcl3 ( 10 ml ) . the chloroform solution was then filtered to remove kcl and k(acac ) , pentane ( 30 \n quadrangular pale yellow crystals of [ pt(o , o-acac)(-acac)(dmso ) ] ( 2a ) which separated out from the solution were filtered , washed with pentane , and dried under vacuum ( yield 0.168 g , 50% ) . \n calcd for c12h20o5spt ( 471.441 ) : c 30.57 , h 4.28 ; found c 30.73 , h 4.34 . \n hnmr in cdcl3 ( 298 k ) : 2.00s [ 3h , ch3(o , o-acac ) ] , 1.95s [ 3h , ch3(o , o-acac ) ] , 5.53s [ 1h , ch(o , o-acac ) ] , 2.29s [ 6h , ch3(-acac ) ] , 4.79s [ 1h , ch(-acac ) , jh - pt 120 hz ] , 3.31s [ 6h , ch3(dmso ) , jh - pt 19 hz ] . \n c nmr in cdcl3 ( 298 k ) : 27.50 and 27.3 [ 2c , ch3(o , o-acac ) ] , 102.2 [ 1c , ch(o , o-acac ) ] , 185.8 and 184.9 [ 2c , co(o , o-acac ) ] , 30.9 [ 2c , ch3(-acac ) ] , 42.0 [ 1c , ch ( -acac ) ] , 208.5 [ 2c , co(-acac ) ] , 42.9 [ 2c , ch3(dmso ) ] . \n pt nmr in cdcl3 ( 298 k ) : 3198 . to a chloroform ( 3 ml ) \n solution of 1a or 2a ( 0.1 g , 0.24 mmol for 1a and 0.1 g , 0.21 mmol for 2a ) a large dms excess ( 0.224 g , 3.6 mmol for 1a and 0.263 g , 4.24 mmol for 2a ) was added . \n the resulting yellow solution was added to pentane ( 10 ml ) and kept at 5c for one day up to the formation of yellow needles crystals for 1b and pale yellow crystals for 2b . finally , \n ( yield 0.075 g , 0.191 mmol , 80% for 1b . anal . \n calcd for c7h13clo2pts ( 391.773 ) : c 21.46 ; h 3.34 ; found : c 21.27 ; h 3.20 ; yield 0.078 g , 0.171 mmol , 82% for 2b . \n calcd for c7h13clo2pts ( 455.428 ) : c 31.65 ; h 4.43 ; found : c 31.72 ; h 4.56 ) . \n k ) : 1.97s [ 3h , ch3(o , o-acac ) ] , 1.88s [ 3h , ch3(o , o-acac ) ] , 5.48s [ 1h , ch(o , o-acac ) ] , 2.33s [ 6h , ch3(dms ) , jh - pt 48 hz ] . hnmr in cdcl3 of 2b ( 298 k ) : 1.89s [ 3h , ch3(o , o-acac ) ] , 1.95s [ 3h , ch3(o , o-acac ) ] , 5.47s [ 1h , ch(o , o-acac ) ] , 2.20s [ 6h , ch3(-acac ) ] , 4.88s [ 1h , ch(-acac ) , jh - pt 124 hz ] , 2.29s [ 6h , ch3(dms ) , jh - pt 51 hz ] . \n c nmr in cdcl3 of 1b ( 298 k ) : 26.1 and 26.5 [ 2c , ch3(o , o-acac ) ] , 101.7 [ 1c , ch(o , o-acac ) ] , 184.9 and 182.9 [ 2c , co(o , o-acac ) ] , 22.1 [ 2c , ch3(dms ) ] . \n c nmr in cdcl3 of 2b ( 298 k ) : 27.50 and 27.1 [ 2c , ch3(o , o-acac ) ] , 101.6 [ 1c , ch(o , o-acac ) ] , 183.7 and 184.7 [ 2c , co(o , o-acac ) ] , 30.9 [ 2c , ch3(-acac ) ] , 40.5 [ 1c , ch ( -acac ) ] , 207.2 [ 2c , co(-acac ) ] , 22.1 [ 2c , ch3(dms ) ] . \n\t\t\t\t\t\t pt nmr in cdcl3 of 1b ( 298 k ) : 2096 . \n pt nmr in cdcl3 of 2b ( 298 k ) : 2905 . \n a solution containing the platinum complex ( approximately 2 10 mmol ) and an excess of guo , 5-gmp , or l - methionine ( 1.6 10 mmol ) dissolved in d2o ( 1 ml ) was placed in an nmr tube and the reaction monitored by h nmr spectroscopy . \n for all complexes tested , the reaction with guo and 5-gmp was negligible after 24 h , whereas the l - methionine instantly reacted with the initial pt complexes . \n two strains of salmonella typhimurium , ta98 and ta100 ( kindly supplied by department of experimental studies and applied medicine , hygiene section , university of brescia ) , histidine auxotroph mutants , deficient in the synthesis of histidine ( his ) , amino acid necessary for bacterial growth were used according with the method proposed by ames et al . . \n these strains contain other mutations that greatly increase the ability to detect mutagens : the mutation \n causes partial loss of the lipopolysaccharide barrier coating the surface of the bacteria and increases permeability to large molecules such as benzo[a]pyrene that do not penetrate the normal cell wall ; the mutation \n uvrb is a deletion of a gene coding for dna excision repair system , resulting in a high sensitivity to uv rays ; the r - factor plasmid , pkm101 , carries ampicillin resistance gene . \n the histidine auxotrophs will only grow in a medium containing sufficient histidine supplement . to revert to histidine production ( prototrophy ) , or become his+ , \n a reverse mutation must occur in the original his mutation site ( found in one of the genes involving histidine biosynthesis ) . \n each sample was investigated with the plate incorporation test : 100 l / ml of complexes ( 1a , 2a , and 2b ) , at different dilutions with dmso ( from 0.01 g / plate to 30 g / plate ) , were added to 2 ml top agar and to 100 l of culture of s. typhimurium growth at optimal concentrations ( 10 u.f.c / ml ) . \n three plates were incubated for each of the dilutions tested . a solvent control ( dmso ) \n furthermore , a positive control was carried out using cisplatin , known as compound at strong mutagenic activity [ 32 , 33 ] , testing the same dilutions of new compounds . \n the results were expressed as numbers of net revertants , calculated as difference between the number of revertants / plate of tested compounds and the number of spontaneous revertants enumerated on the control plates . \n moreover , we calculated the mutagenicity ratio ( mr)the ratio of the number of salmonella typhimurium revertants grown in the presence of the tested complex to the number of spontaneously appeared revertants ( on the negative control ) . \n the synthesis of [ ptcl(o , o-acac)(dmso ) ] ( 1a ) , containing a single chelate acac , was straightforward . \n due to its low solubility in the reaction medium , it precipitates as a pale yellow powder from the reaction mixture of k[ptcl3(dmso ) ] with acetylacetone and koh in water . \n complex 2a was obtained by treating cis-[ptcl2(dmso)2 ] with acetylacetone and koh in meoh and was isolated from their respective reaction mixtures by an appropriate workup procedure reported in the experimental section ( scheme 2 ) . in both cases , in order to prevent metal reduction , a slight excess of acetylacetone was used with respect to the calculated stoichiometric amount of koh based on starting platinum complex . \n it should be noted that the use of the scarcely soluble cis-[ptcl2(dmso)2 ] as a starting platinum complex for the preparation of 1a in meoh or water gave unsatisfactory results . due to the low solubility of cis-[ptcl2(dmso)2 ] , the reaction with acetylacetone and koh in meoh resulted in an excess of acac in solution , even when using a stoichiometric or substoichiometric amount of acac and always gave a mixture of 1a , 2a and unreacted starting material . \n on the other hand , the reaction of cis-[ptcl2(dmso)2 ] with acetylacetone and koh in water , in which both the starting platinum complex and [ ptcl(o , o- acac)(dmso ) ] are sparingly soluble , gave analytically pure 1a although a longer reaction time was required and a lower yield was obtained . \n in the presence of dimethylsulfide ( dms ) , [ ptcl(o , o-acac)(dmso ) ] ( 1a ) and [ pt(o , o-acac)(-acac)(dmso ) ] ( 2a ) complexes selectively undergo substitution of the sulfur ligand to give the analogous dms complexes [ ptcl(o , o-acac)(dms ) ] ( 1b ) and [ pt(o , o-acac)(-acac)(dms ) ] ( 2b ) . \n interestingly , the substitution reaction appears to be very selective not only for 1a , where dmso is the only expected exchangeable ligand , but also for 2a , where , in principle , the chloroligand was also able to undergo substitution with dms . \n therefore , the synthetic procedures of 1b-2b complexes reported in the experimental section were developed , taking advantage of the selective reactivity showed by 1a-2a compounds towards soft ligand such as dms . \n for the synthesis of 1b and 2b complexes , an excess of dms was added to 1a and 2a , in order to complete the substitution reaction ( scheme 3 ) . by h \n nmr the reactivity of water soluble complexes ( 1a , 2a , and 2b ) with biological nucleophiles ( nucleobases and amino acids ) was investigated . \n the poor water solubility of [ ptcl(o , o-acac)(dms ) ] ( 1b ) prevented further investigation on its reactivity and biological activities . \n the reactions with soft biological nucleophiles , such as l - methionine ( l - met ) , rapidly gave the same selective substitution of dmso or dms , already seen for these complexes towards classical soft nucleophiles ( dms , pph3 , ethylene , carbon monoxide ) . \n indeed , also in the presence of l - methionine excess both 1a and 2a complexes gave selective substitution reaction of dmso affording , respectively , to the neutral species [ ptcl(o , o-acac)(l - met ) ] [ pt(o , o-acac)(-acac)(l - met ) ] . \n moreover , this substitution reaction not only was more selective but also was faster . in figure 1 \n the h nmr time monitoring of reaction of 1a with l - met was reported . \n adding l - met excess to a solution of 1a in d2o , after only 5 minutes ( the time needed to record a h nmr spectra ) the substitution of dmso ligand and the coordination of l - met were observed by the decreasing of the signal at 3.44 ppm , assigned to the coordinated dmso ligand . at the same time , the increasing of the singlet at 2.6 ppm , attributed to the free dmso ligand , and the appearance of new signals related to the o , o-acac carrier ligand were detected . after 10 minutes , almost the entire starting complex was reacted with the l - met . \n the substitution reaction of 1a and 2a with soft biological nucleophiles ( l - met ) was more selective , especially in the case of 1a , where another good leaving group such as cl is present in the coordination sphere . \n contrary , in the reactions with biological nitrogen ligands , such as purines ( guo , 5-gmp ) , both 1a and 2a showed little reactivity even after several hours . in the h nmr spectra in d2o of 1a in the presence of 5-gmp ( figure 1 ) \n no new signals of coordinated or free dmso ligand assignable to substitution reaction products were observed . \n the same selective reactivity in the substitution of the soft sulfur ligand was observed in the reaction of the water soluble [ pt(o , o-acac)(-acac)(dms ) ] ( 2b ) with l - methionine , guo , and 5-gmp . \n also in this case a very fast substitution reaction was noted in the presence of l - met excess . in figure 2 \n by addition of l - met excess to a deuterated water solution of 2b , the decreasing of singlet at 2.29 ppm , attributed to coordinated dms ligand , and the increasing of new signal of o , o-acac and -acac , assigned to the [ pt(o , o-acac)(-acac)(l - met ) ] species , were identified after only 10 minutes . \n analogously to 1a and 2a complexes , in the h nmr time monitoring of the reaction of 2b with guo or 5-gmp ( figure 2 ) any substitution reaction occurred . \n such behaviour is very peculiar and suggests a possible selectivity in the substitution reaction at the metal centre in these systems ruled by the hard - soft characteristics of the leaving and incoming ligands \n . this selectivity could be also operating when the substitution at the metal involves biological sulfur ligands such as thiols or thioethers attached to proteins . \n furthermore , these compounds not only induced apoptosis in endometrial cancer cells ( hela ) , but also showed high cytotoxicity in cisplatin - resistant breast cancer cell lines , with activity up to about 100 times higher with respect to cisplatin and in vitro antimetastatic activity . among all complexes , [ pt(o , o-acac)(-acac)(dms ) ] ( 2b ) \n differently from cisplatin , for which the activity appears to be associated to both cellular accumulation and dna linking , intracellular total platinum amount analysis indicated a scarce reactivity of new complexes with dna , the principal biological target of cisplatin [ 21 , 22 ] . \n moreover recent in vivo studies aimed to evaluate the outcomes of perinatal treatment with chemotherapeutic agents on key cns developmental processes such as neural cells proliferation , migration , and differentiation demonstrated that the brain platinum content after [ pt(o , o-acac)(-acac)(dms ) ] treatment was notably higher ( approximately 4-fold as much ) than after cisplatin . \n however , compared with cisplatin , [ pt(o , o-acac)(-acac)(dms ) ] induces less severe changes on fundamental events of neuroarchitecture development . \n all these data suggested that the cytotoxicity mechanisms of the new complexes may not necessarily require interaction with dna and that their cytotoxicity is associated only with the intracellular accumulation . \n the ames ' test , carried out on the new complexes , confirmed these results . \n the mutagenic activities of new complexes ( 1a , 2a , and 2b ) with respect to cisplatin on two salmonella typhimurium strains ( ta98 and ta100 ) were reported in figure 3 and table 1 . as expected a rising of revertants at increasing doses of cisplatin \n was observed , reaching the highest number of net revertants at the highest tested doses ( 30 g / plate ) on both strains . \n interestingly , at the same tested doses and on both salmonella typhimurium strains the new complexes showed negligible mutagenic activity . \n indeed , also at the highest tested doses no net revertants colonies were observed , whereas only cisplatin exhibited the well - known [ 32 , 33 ] dose - dependent increase in revertants . \n hence , we can assert that the biological activity of the new pt(ii ) acac complexes is related to the reaction with nongenomic biological targets . \n we have reported new pt(ii ) -diketonate complexes with an intriguing chemical reactivity and interesting biological activities . \n the new complexes coordinate , instead of the mono- and bidentate amine ligands of the classical cisplatin analogues , o , o-acetylacetonate ( acac ) chelate as carrier ligand and dms or dmso ligands . due to their ability to induce apoptosis in endometrial cancer cells ( hela ) and in cisplatin - resistant breast cancer cell lines ( mcf-7 ) with different pathways with respect to cisplatin \n , further investigations were performed on the reactivity of novel compounds with biological targets and on the mutagenic capability . \n indeed , differently from cisplatin , for which the activity appears to be associated with its intracellular accumulation and formation of dna adducts , the cytotoxicity of the new compound is only related to the intracellular accumulation . \n these complexes , besides their specific biological activity , showed an interesting and selective chemical reactivity towards nucleophile with different hsab ( hard - soft acid - base ) character . \n the same selective reactivity has been studied towards biological nucleophiles , such as nucleobase and amino acids . \n the new complexes showed also in these cases negligible reactivity with nucleobases ( guo and 5-gmp ) and gave selective substitution of dmso or dms with soft biological nucleophiles , such as l - methionine , suggesting that the cellular targets could be amino acid residues in proteins and enzymes involved in the apoptotic induction . \n interestingly , in the mutagenic tests carried out in this work on two salmonella typhimurium strains ( ta98 and ta100 ) the new complexes showed , also at the highest tested doses , insignificant mutagenic activity with respect to cisplatin , known for its strong mutagenic activity and then used as a positive control . \n all these data suggest that the cytotoxicity mechanisms of the new -diketonate complexes may not necessarily require interaction with dna and that their biological activity is connected to the reaction with nongenomic biological targets .", "role": "user" }, { "content": "new platinum(ii ) complexes [ ptcl(o , o-acac)(l ) ] ( 1 ) and [ pt(o , o-acac)(-acac)(l ) ] ( 2 ) ( l = dmso , a ; dms , b ) containing a single chelated ( o , o-acac ) ( 1 ) , or one chelated and one -bonded ( -acac ) acetylacetonate ( 2 ) have been synthesized . \n the new pt(ii ) complexes exhibited high in vitro cytotoxicity on cisplatin sensitive and resistant cell lines and showed negligible reactivity with nucleobases ( guo and 5-gmp ) but selective substitution of dmso / dms with soft biological nucleophiles , such as l - methionine . in order to assess the ability of the new complexes with respect to cisplatin to induce apoptosis by interaction with nongenomic targets , the ames ' test , a standard reverse mutation assay , \n was carried out on two salmonella typhimurium strains ( ta98 and ta100 ) . \n interestingly , the new complexes did not show the well - known mutagenic activity exhibited by cisplatin and are , therefore , able to activate apoptotic pathways without interacting with dna .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: 20% require blood products , re - exploration , or both . in spite of standard therapy \n massive blood loss , multiple blood transfusion , and re - exploration required in such cases are associated with multiple organ failure and prolonged hospital stay.1 refractory postoperative bleeding is a life - threatening complication following cardiac surgery and presents a challenge for surgeons , anesthetists and perfusionists . \n refractory bleeding is resistant to ordinary methods of treatment , ie , transfusion of blood and blood products to correct coagulation profiles . \n the patients developed continued brisk blood loss in chest drain despite correction of coagulopathy , hypothermia , and surgical re - exploration . \n but the most common reason for uncontrolled bleeding is derangement of the coagulation pathway . during cardiopulmonary bypass ( cpb ) , the complement cascade , the kinin system , and the coagulation system are all activated and could result in refractory bleeding . \n in addition , patients who undergo emergency coronary surgery are more likely to have been treated with thrombolytic agents , high dose heparin , and high doses of antiplatelet drugs , all of which could accentuate a coagulopathy after surgery . with cpb , \n microvascular bleeding develops secondary to acquired hemostatic system abnormalities that include : ( 1 ) hemodilution secondary to volume resuscitation or loss of platelets and coagulation factors ; ( 2 ) effects of hypothermia on both plasma coagulation factors and platelet function ; ( 3 ) consumption coagulopathy due to tissue injury , contact activation , and transfusion of shred pericardial blood ; and ( 4 ) residual heparin or heparin rebound.2 treatment of postoperative bleeding involves exclusion of a surgical source of bleeding and the identification and treatment of specific coagulation abnormalities , in combination with the use of thrombogenic agents such as tranexamic acid and protamine . \n activated recombinant factor vii ( rfviia ) ( novoseven , novo nordisk , inc , bagsvrd , denmark ) is used as rescue therapy after all conventional therapy has failed . \n the aim of this study was to review our use of rfviia for refractory bleeding after cardiac surgery . \n this retrospective study was carried out from a review of the medical records of all patients who received rfviia for refractory postoperative bleeding following cardiac surgery at a regional center between april 2007 and april 2009 . during this period , \n ten patients received rfviia , six males and four females , with a median age of 72.5 years ( range 5981 years ) . \n seven patients were on anticoagulant therapy on the day of surgery : three on aspirin , one on unfractionated heparin , two on clopidogrel , and one had been treated with intravenous unfractionated heparin , aspirin , and clopidogrel on the day of surgery . \n patients demographics are outlined in table 1 . in our center , conventional medical therapy to achieve hemostasis starts with tranexamic acid at the beginning and end of the operation . for reversal of heparin after weaning from cpb , protamine is given at a dose of 1 g per 100 units of heparin . \n further doses of protamine are administered either to achieve the pre - operative activated clotting time ( act ) or an act < 130 seconds . \n fresh frozen plasma , platelets , and red cell concentrates were used as appropriate , based on laboratory results of the coagulation screen . for refractory bleeding \n , rfviia is administered at a mean intravenous bolus dose of 65 g / kg ( range 5580 g / kg ) . \n novoseven is available in the hospital in 1.2 , 2.4 , and 5 mg vials . according to body weight , \n data are expressed as mean standard error of the mean , or median ( range ) . \n analyses were performed using spss statistics software ( v 19.0 ; ibm corporation , somers , ny ) . \n in our center , conventional medical therapy to achieve hemostasis starts with tranexamic acid at the beginning and end of the operation . \n for reversal of heparin after weaning from cpb , protamine is given at a dose of 1 g per 100 units of heparin . \n further doses of protamine are administered either to achieve the pre - operative activated clotting time ( act ) or an act < 130 seconds . \n fresh frozen plasma , platelets , and red cell concentrates were used as appropriate , based on laboratory results of the coagulation screen . for refractory bleeding \n , rfviia is administered at a mean intravenous bolus dose of 65 g / kg ( range 5580 g / kg ) . \n all ten patients received two consecutive doses of rfviia . novoseven is available in the hospital in 1.2 , 2.4 , and 5 mg vials . according to body weight , \n data are expressed as mean standard error of the mean , or median ( range ) . \n analyses were performed using spss statistics software ( v 19.0 ; ibm corporation , somers , ny ) . \n ten patients underwent cardiac surgery with cpb ; four were elective , and six were emergency procedures . \n the median cpb time was 125 minutes ( range 27560 minutes ) , and median cross - clamp time was 66 minutes ( range 19120 minutes ) . \n the mean european system for cardiac operative risk evaluation score ( euroscore ) was 6.9 0.9 , and mean logistic euroscore was 8.3 1.7 . \n two patients underwent aortic root surgery , and the rest of the patients underwent coronary artery surgery . \n blood loss 6 hours prior to treatment was 1758.5 163.9 ml , and blood loss in the 6-hour period post treatment was 405.6 50.5 ml ( p < 0.05 ) . \n all patients received blood and blood products after bleeding . the amount of blood and blood product reduced significantly after administration of rfviia . \n blood and blood products used in the 6-hour period before and after administration of rfviia were 19.6 1.5 u and 4.4 0.6 u respectively ( p < 0.05 ) . \n ten patients underwent cardiac surgery with cpb ; four were elective , and six were emergency procedures . \n the median cpb time was 125 minutes ( range 27560 minutes ) , and median cross - clamp time was 66 minutes ( range 19120 minutes ) . \n the mean european system for cardiac operative risk evaluation score ( euroscore ) was 6.9 0.9 , and mean logistic euroscore was 8.3 1.7 . \n two patients underwent aortic root surgery , and the rest of the patients underwent coronary artery surgery . \n blood loss 6 hours prior to treatment was 1758.5 163.9 ml , and blood loss in the 6-hour period post treatment was 405.6 50.5 ml ( p < 0.05 ) . \n all patients received blood and blood products after bleeding . the amount of blood and blood product reduced significantly after administration of rfviia . \n blood and blood products used in the 6-hour period before and after administration of rfviia were 19.6 1.5 u and 4.4 0.6 u respectively ( p < 0.05 ) . \n in this limited series , we noted a reduction in the rate of blood loss in all cases . there were no nonresponders . \n although the use of rfviia was not randomized with a control arm , this consistency in response following administration of the drug suggests a cause - and - effect rather than a simple association . as suggested by previous reports , we attempted in all cases to correct coagulopathy with the use of clotting factors and avoid the use of this drug in the presence of acidosis . \n guidelines on blood conservation clinical practice state that factor viia may be considered for the management of intractable bleeding that is unresponsive to routine hemostatic therapy.3 although there have been case reports and observational studies , there are no clear - cut guidelines on appropriate dose or the timing of use of this drug . \n the patients received a mean dose of 65 g / kg within 2 hours of refractory bleeding . \n the timing of its use is crucial due to the perquisite requirement of the presence of adequate circulating clotting factors for effectiveness of rfviia . \n this is consistent with observations of other groups that have noted an increased effectiveness with the use of rfviia earlier and in presence of adequate coagulation factors.4 rfviia stimulates the coagulation cascade by activation of thrombin at the site of tissue injury by tissue factor - dependent and -independent mechanisms ( when 10-fold higher doses of factor viia are available in the vicinity).5 tissue factor is exposed on the subendothelial surface and on the surface of neutrophils , monocytes , and platelets during an inflammatory response . \n a tissue factor - dependent mechanism results in factor x activation , and activated factor x in combination with factor v leads to the generation of thrombin . it is also reported that rfviia can directly activate factor x on phospholipid vesicles , activated monocytes , and on the platelet surface without the presence of tissue factor.6 this tissue factor - independent mechanism of thrombin formation is also valuable . all of the enhanced thrombin generation results in recruitment , activation , and aggregation of platelets , that results in formation of stabilized clots , which are resistant to fibrinolysis . \n however , severe hypothermia ( 33c ) and acidosis ( ph < 7.2 ) reduce the effect of factor vii , so these must be corrected prior to administration of rfviia . \n significant concerns have arisen over the safety , efficacy , and cost of the use of rfviia in cardiac surgical patients.79 the interaction of rfviia with antifibrinolytic drugs could potentially increase the risk of life - threatening thrombotic events . \n raivio et al has demonstrated 25% mortality and 25% thrombotic events after administration of rfviia.10 other groups have reported 5%32% mortality rate4,7,11 and 4%5.3% rate of thromboembolic events.9,11,12 in our series we did not encounter any thromboembolic events . there were no episodes of thrombotic graft occlusion despite the presence of significant coronary artery disease ( 80% ) . \n the variations in the adverse event rates suggest that these are likely to be multifactorial with pre - existent morbidity , complexity of surgery , presence of underlying and perhaps undiagnosed coagulopathy , and dose of prothrombotic drugs playing a role . \n once again , the variations in the mortality rates reported by other groups make it difficult to ascertain whether mortality was a direct result of the use of this drug or the presence of comorbid conditions as well as the length and complexity of the operative procedure . in our series , \n we used an average dose of 65 g / kg on our patients in this series , in keeping with recommendations by other groups.4,13 with the off - label use of this drug in patients following cardiac surgery , there are no recommendations from the manufacturer on appropriate dosing schedule . \n however , in this series , we noted a response in all patients with the use of 65 g / kg . \n other groups have noted an increased incidence of adverse effects with the use of higher doses of the drug.4,14 in theory , a randomized control trial ( rct ) is necessary to remove doubts over the effectiveness of this drug , serious adverse events directly related to its use and optimum timing of use . in practice , however , an rct is difficult to carry out due to the infrequent occurrence of refractory bleeding following cardiac surgery and the critical nature of this clinical situation . \n the identification of patients in whom the use of factor viia are likely to be of value can be more realistically identified by case - series and observational studies . \n the limitations of our studies are single institution basis , lack of control population , modest sample size , and relatively short follow - up period . \n the desirable outcomes , minimal complications , and patient tolerance suggest that rfviia can be used effectively as rescue therapy in refractory bleeding after cardiac surgery . \n the limitations of our studies are single institution basis , lack of control population , modest sample size , and relatively short follow - up period . \n the desirable outcomes , minimal complications , and patient tolerance suggest that rfviia can be used effectively as rescue therapy in refractory bleeding after cardiac surgery . \n in our series , rfviia was associated with a reduction in blood loss and reduced need for transfusion of blood products . \n we conclude that this case series gives better understating of rfviia administration in refractory bleeding in cardiac surgery . \n multicenter , rcts are prerequisite for firm conclusions regarding appropriate dosing regime and safety profile of rfviia in cardiac surgery patients .", "role": "user" }, { "content": "background : refractory post cardiopulmonary bypass ( cpb ) bleeding continues to cause concern for cardiac surgeons and intensivists . \n massive postoperative hemorrhage following cpb is multifactorial and not fully understood , and it is also associated with increased mortality and morbidity . activated recombinant factor vii ( rfviia ) has emerged as possible salvage medication in refractory post cardiac surgical bleeding . this observational study sought to identify the pattern of use of rfviia in cardiac surgery , its effectiveness , and risk.methods:this study involved a retrospective case review of medical records of ten patients undergoing a variety of cardiac surgery procedures and who developed life - threatening bleeding during surgery or after surgery despite conventional medical therapy , including transfusion of blood and blood products , and received rfviia at a regional center between august 2007 and april 2009.results:all ten patients received two consecutive doses of rfviia ( average dose 65 g / kg ) at a 2-hour interval . \n eight patients were re - explored due to massive postoperative bleeding or cardiac tamponade before receiving rfviia . \n surgical sources of bleeding were not identified in any cases . \n a second re - exploration was carried out in two cases . \n two patients ( 20% ) died in itu from problems not related to bleeding and thromboembolism . \n blood loss was significantly reduced after administration of rfviia . \n blood loss 6 hours prior to treatment was 1758.5 163.9 ml and blood loss in the 6-hour period post treatment was 405.6 50.5 ml ( p < 0.05 ) . \n blood and blood products used in the 6-hour period before and after administration of rfviia were 19.6 1.5u and 4.4 0.6u , respectively ( p < 0.05 ) . \n no adverse reactions or thrombotic complications related to rfviia were noted.conclusion:in our limited study , use of rfviia in refractory post surgical bleeding was significantly reduced blood loss and use of blood and blood products . \n we concluded that rfviia can be used satisfactorily and safely as a rescue therapy in the management of post cardiac surgical bleeding .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: for a large chest wall defect measuring 25 cm 20 cm resulting from the excision of a recurrent cystosarcoma phyllodes involving ribs 4 to 9 , skeletal stabilization was provided by a prolene mesh methylmethacrylate sandwich and the soft tissue repair was done by a combined anterolateral and anteromedial thigh flap on two separate vascular pedicles . along with the case description we present the vascular anatomy of this dual flap . \n a 52-year - old woman presented with recurrent cystosarcoma phyllodes of the left breast 12 years after primary resection [ figure 1 ] . \n recurrent cytosarcoma phyllodes intra - operatively , a large tumour measuring 12 cm transversely was found adherent to the chest wall , invading the skin , ribs and pleura . \n the thoracic surgeon resected the entire left anterolateral chest wall from the midsternum to the midaxillary line , comprising skin , intercostal muscles and ribs 49 with underlying pleura , leaving a 25 cm 20 cm defect . \n methymethacrylate cement sandwich [ figure 2a ] , followed by immediate soft - tissue reconstruction . \n we harvested a combined musculocutaneous anterolateral thigh ( alt ) with anteromedial thigh ( amt ) flap , including the vastus lateralis and rectus femoris muscles , giving us two separate pedicles . \n the flap was revascularised using two sets of recipient vessels , namely the thoracodorsal and the thoracoacromial arteries . \n extra venous drainage was facilitated by a long saphenous vein graft for the alt [ figure 2b ] . \n she was able to ambulate with a walking aid and lived for another 1 year before she succumbed to distant metastases [ figure 4 ] . \n ( a ) prolene mesh - methymethacrylate sandwich prosthesis , ( b ) flap inset and revascularisation ( a ) lateral circumflex femoral system supplying the rectus femoris and vastus lateralis muscles and ( b ) cadaveric specimen showing the design of the flap . \n the options for large chest wall defects range from local , pedicled ( latissimus dorsi , pectoralis major , external oblique or rectus abdominis ) muscle or free tissue transfer ( single or multiple ) according to chang et al . in our case \n the tram flap was precluded as both internal mammary vessels were ligated , and chasing what was left as a recipient vessel for a free tram would be challenging . \n other free flap options were a large thigh flap or a contralateral latissimus dorsi flap . \n the alt flap has been popularized for its versatility and its vascular anatomy is well described.[36 ] most surgeons would limit its dimensions to 24 cm 12 cm . to increase its dimension , we combined it with an amt flap , resulting in a 25 cm 20 cm skin paddle . in the majority of cases , \n the amt flap is supplied by perforators arising from the descending branch of the lateral circumflex femoral artery . rarely , the perforators arise from the lateral circumflex femoral artery itself , the superficial femoral artery or directly from minor muscle branches to the rectus femoris . \n our combined flap was supplied by the descending branch [ figure 2 ] , but we separated it into two pedicles to improve circulationand safeguard against thrombosis . \n we included the vastus lateralis and rectus femoris to maximise muscle coverage , to improve local vascularity and offset the hard palpability of the underlying cement prosthesis . \n lastly , we chose not to raise it as a perforator flap as experience has shown that very large alt flaps based on even two to three perforators can still show marginal necrosis and , more importantly , laying bare perforators against a cement base would risk vessel spasm . \n this patient had successful coverage of a large cement prosthesis with preservation of thoracic function . \n the main drawback was knee weakness from sacrifice of the vastus lateralis and rectus femoris muscles .", "role": "user" }, { "content": "we present a massive 25 cm 20 cm chest wall defect resulting from resection of recurrent cystosarcoma phyllodes of the breast along with six ribs exposing pleura . \n the chest wall was reconstructed with a prolene mesh \n methylmethacrylate cement sandwich while soft tissue reconstruction was carried out using a combined free anterolateral \n anteromedial thigh musculocutaneous flap with two separate pedicles , anastomosed to the thoracodorsal and thoracoacromial vessels respectively . \n we explain our rationale for and the advantages of combining the musculocutaneous anterolateral thigh flap with the anteromedial - rectus femoris thigh flap .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: many women increasingly delay pregnancy and childbirth into their fourth decade of life because of different reasons , such as delay in marriage , educational and professional reasons . some of them experience pregnancy unwillingly because of inappropriate use of contraceptive methods . \n the association between advanced maternal age and increased risk of chromosomal abnormalities and spontaneous abortion has been well documented in studies [ 3 , 4 ] . \n there are different publications in the literature on pregnancy outcomes of women aged 40 years or older . \n some authors have reported that advanced maternal age has been associated with preterm delivery , low birth weight , perinatal mortality , and higher frequency of cesarean section [ 5 , 6 ] . \n but others have reported no obvious difference in the perinatal outcomes , obstetric outcomes , birth weight , apgar score , and admission to neonatal intensive care unit between younger and older mothers . \n the aim of this study was to determine the effect of maternal age on obstetric and perinatal outcome in multiparous women aged at least 40 year old with multiparous women aged 2029 years . \n this is a retrospective study for women delivered at gestational ages of > 20 weeks in bezmialem vakif university and haseki education and research hospital between october 2010 and december 2011 . \n we reviewed the obstetric records of 97 multiparous women aged 40 or above at the time of delivery and compared with a control group which consisted of consecutive 97 multiparous women with ages 2029 years who delivered at the same period of time . \n the following data , including maternal age at the time of delivery , gravidity , parity , gestastional age , antenatal complications ( pregnancy - induced hypertension , diabetes , preterm delivery , delivery < 24 weeks , abruptio placenta , small for gestational age , large for gestational age ) , mode of delivery , indications for ceaserean sections , intrapartum , and neonatal outcome ( fetal distress , fetal complication , fetal malformation , birth weight , apgar score , neonatal intensive care unit admission , and stillbirth ) were collected and compared with a control group . \n gestational age was determined on the basis of either date of last menstrual period or ultrasound examination . \n diastolic blood pressure > 90 mmhg was defined as hypertension in pregnancy ( essential or pregnancy - induced hypertension ) . \n diabetes mellitus was considered as history of diabetes ( based on medical records ) or gestational diabetes . \n like other studies , we combined chronic hypertension , pregnancy - induced hypertension , and eclampsia into one condition called hdp ( hypertensive disorders of pregnancy ) , and we combined gestational and established diabetes into another . \n abruptio placentae refers to the premature separation of the normally implanted placenta from the uterus . \n small for gestational age ( sga ) was defined as < 10th percentile of birth weight for gestational age and large for gestational age ( lga ) as 90th percentile . \n stillbirth was defined as intrauterine death of a fetus weighing at least 500 g after 20 completed weeks of gestation . \n low apgar score was defined as a score of less than seven at 5 min following birth . \n statistical analysis was performed using the medcalc for windows , version 8.1.00 ( medcalc software , mariakerke , belgium ) . data were presented as means standard deviations or numbers of subjects and percent . \n odds ratio ( or ) and 95% confidence intervals ( ci ) are presented in order to analyse the risk related with advanced maternal age , and p < 0.05 was regarded as statistically significant . \n the mean age of women in the study group was 41.2 1.7 years and that in the control group was 25.4 2.3 years at the time of delivery . \n the older mothers had a higher mean gravidity compared with for the control group ( 4.9 2.5 versus 2.6 1 , p < 0.0001 ) . \n gestational age at the delivery was lower among the older mothers compared with the younger women ( table 1 ) . \n the incidence of hypertension and diabetes mellitus was significantly higher in older women compared with the younger group . \n abruptio placenta , delivery before 24 weeks , preterm delivery , and lga were seen more often among older mothers but the difference did not reach the level of significance ( table 2 ) . \n the infants of the older mothers showed a higher incidence of stillbirth ( 5.1% versus 0% ) , admission to the neonatal intensive care unit ( 5.1% versus 1.03% ) , and fetal malformation ( 3.09% versus 0.8% ) than younger mothers , but the differences were not statistically significant . \n the results showed that the rate of fetal complication ( p = 0.021 ) , 5-minute apgar scores < 7 ( p = 0.032 ) were significantly higher among older mothers ( table 3 ) . \n the cesarean section delivery rate was 65.9% in the study group and 55.6% in the control group , respectively . \n the repeat cesarean sections in both groups were performed after the onset of labour , no programmed section was performed in any of the groups . \n the major indication for cesarean delivery in this study included previous cesarean section in both groups . \n the incidence of cesarean section for fetal distress ( p = 0.017 ) and fetal macrosomia ( p = 0.041 ) was significantly higher in the group of older mothers than in the younger mothers ( table 4 ) . \n the risk of hypertension ( or , 6.7 ; 95% ci , 1.4530.8 ; p = 0.014 ) , diabetes mellitus ( or , 18.5 ; 95% ci , 1.05 - 325 ; p = 0.046 ) , and 5 minute apgar score < 7 ( or , 8.62 ; 95% ci , 1.0570.3 ; p = 0.044 ) were higher among the older group . the rate of cesarean delivery was higher in older group ( or , 1.54 ; 95% ci , 0.862.7 ; p = 0.14 ) but the difference was not statistically significant ( table 5 ) . \n our study confirms a significant higher incidence of hypertension and diabetes mellitus among pregnant women age 40 and older , which has been reported in other studies [ 1214 ] . \n the prevalence of diabetes and hypertension are increased by age and considered to induce vascular endothelial damage that occurs with aging . \n contrary to the literature [ 12 , 16 , 17 ] , the cesarean section was slightly higher in the older multiparous mothers aged 40 and older compared with younger multiparous mothers in our study . \n many reports have described a higher incidence of cesarean delivery among the nulliparous women age 40 or older [ 5 , 18 ] . \n elderly primiparous women frequently have a long history of infertility and the probability of this being the only pregnancy may influence a physician 's decisions to perform caesarean delivery . \n this suggested that parity imposed a more important effect on the incidence of cesarean section than maternal age . in this study , \n the incidence of placental abruption was higher in women aged 40 years or older than younger women , this difference was not significant . \n the primary indication for cesarean section in this study was previous caesarean delivery in both groups . \n the main reason for the high caesarean section rates in the control group ( 90.7% ) is related to the previous caesarean deliveries . \n the caesarean section rates in these young women who had previous caesarean sections is high since the indications of caesarean section is also increased in our country . \n the women in the study group are older and thus they may not be as affected as the younger control group from this rise in the changing trend of the delivery route . additionally , the high rate of cesarean delivery in both groups is due to the fact that our clinic is a tertiary center . \n fetal distress constituted 20 and 3.7% of the indications for caesarean section in older and younger mothers , respectively . \n the rate of cesarean section for fetal macrosomia is accounted for 12.5% in the study group and 1.03% in the control group . \n this significantly higher rate of cesarean section may be related with diabetes mellitus which is clearly regarded as a cause of macrosomia . \n mean gestational age for the older group at delivery was significantly lower than that for the younger group . \n this fact may be associated with maternal or fetal problems such as diabetes , chronic hypertension , and fetal distress which is more frequently seen in older mothers . \n the rate of stillbirth was higher among the older group although the difference was not significant . \n stillbirth occured in 5 cases in the study group in which down syndrome was the reason of death in one case . \n the risks of aneuploidy and fatal congenital anomalies increase with maternal age and , despite antenatal screening , they are likely to have contributed to the increased rate of stillbirth . the failure of uterine vasculature to adapt to the increased hemodynamic demands of pregnancy has also been suggested as a cause of fetal death in women aged 40 years and older . \n this study shows that a 5-minute apgar score < 7 , which is a better indicator of long - term neonatal outcome , was higher in the older mothers compared with the younger ones . \n neonatal intensive care unit admission was more frequent among in the older women although the difference was not statistically significant ( p = 0.21 ) . \n it may be explained by the increased incidence of fetal distress , with lower apgar scores and fetal distress among older patients . \n the rates of preterm delivery , delivery < 24 week were more frequently seen among in the older mothers , although the difference was not statistically significant . maternal and fetal complications such as hypertensive diseases , diabetes , and fetal distress may contribute to the increased risk of preterm delivery among the multiparous women aged 40 years and older . \n therefore , this would suggest that maternal age may not affect birth weight as much as other factors . in conclusion , pregnancy in older multiparous women \n seem to have higher rates of obstetric complications and adverse birth outcomes , such as hypertension , diabetes , and lower apgar scores . \n women should be informed that the risk of pregnancy complications and adverse birth outcome increases with age . \n additional studies are needed to examine the relationship between maternal age and maternal and fetal outcomes and the mechanisms on how advanced maternal age increases the risk of adverse birth outcomes in different subgroups of women .", "role": "user" }, { "content": "objective . \n the aim of this study was to evaluate the effect of maternal age on prenatal and obstetric outcome in multiparaous women . \n materials and methods . \n a retrospective case control study was conducted , including women aged 40 years and over ( study group , n = 97 ) who delivered at 20 week 's gestation or beyond and women aged 2029 years ( control group , n = 97 ) . \n results . the mean age of women in the study group was 41.2 \n 1.7 years versus 25.4 2.3 years in the control group . \n advanced maternal age was associated with a significantly higher rate of hypertension , diabetes mellitus , fetal complication , and 5-minute apgar scores < 7 ( p < 0.05 ) . caeserean section rate , incidence of placental abruption , preterm delivery , and neonatal intensive care unit admission were more common in the older group , but the differences were not statistically significant . conclusions . \n advanced maternal age is related to maternal and neonatal complications .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: the study was done by following the tenets of declaration of helsinki and as per the protocol of vision research foundation . \n modern chart construction uses the principles of geometric progression of letter sizes , usage of letters of equal legibility , and normalization of crowding . \n the 10 sloan letters [ c , d , h , v , r , n , s , o , k , and z ] are known to have equal legibility . \n the early treatment diabetic retinopathy study ( etdrs ) charts were constructed using these ten sloan letters and logmar construction design . the pocket vision screener reported in this study \n the task for the subject would be to read the middle five letters in the middle line [ fig . 1 ] . \n the central five letters in each line were created using the letters in the 6/9 line of the etdrs charts . \n only those combinations that differed in their row legibility values by at most 1% were used for the construction of the chart . \n row legibility values were calculated by adding up the legibility scores of the individual letters in that line . \n these calculations were done using the difficulty scores given by sloan . a version of the pocket vision screener . \n the subject 's task is to read the letter ncvoz from a distance of 3 m. the box is included in this picture for clarity ; it does not appear in the pocket vision screener six versions of the screener were constructed . \n two of these had the middle line with letters chosen from the etdrs chart 1 , two with letters chosen from etdrs chart 2 and two from etdrs chart r. the two charts with the same middle line had their first and third lines interchanged [ fig . \n the left and right screeners have their first and the third lines interchanged each of the 10 sloan letters were constructed separately on a 5 5 grid using the image processing software adobe photoshop 7.0 ( adobe systems , inc , california , usa ) . \n the size of the letters was calculated to be 6.92 mm 6.92 mm for viewing at 3 m distance corresponding to a logmar visual acuity of 0.2 ( or approximately 6/9 snellen acuity ) . \n the letters were arranged using the software coreldraw 10 ( corel corporation , ontario , canada ) . \n the spacing between the rows and the spacing between adjacent letters in a row were set equal to 6.92 mm ( the letter size ) . \n the white background was extended to one letter size on all the four sides ; beyond this the screener was completely black . \n the overall size of the screener was 12 cm ( width ) 6.2 cm ( height ) . \n it is an externally illuminated chart intended to be used in a standard illumination of 130215 lux . \n the screeners were printed on a 250 gsm , matt finished paper using a laser printer with the cost of production inr 10 . \n subjects were recruited from the outpatient department of the rural eye hospital , sankara nethralaya , chennai . \n one hundred consecutive patients who could read english alphabets and who had unaided visual acuity better than or equal to 6/60 so as to exclude people with severe visual impairment . \n consecutive patients visiting the optometrist room , which was standardized for testing and who met the required criteria were included in the study . after obtaining oral consent from the subjects , \n unaided visual acuity was tested by a trained optometrist using both the newly constructed pocket vision screener and logmar visual acuity chart . \n all visual acuity testing was performed by a single examiner . for each subject , right eye was chosen as the testing eye and the other eye was occluded . \n subjects were seated at a distance of 3 m from the chart . in the case of visual acuity measurement using the logmar chart , the subjects were instructed to read from the top left and stop reading until they were not able to read anymore letters . \n every correctly read letter was assigned a score of 0.02 and every incorrectly read or unread letter was assigned a score of 0.00 . visual acuity ( logmar ) for each subject was determined using the formula : va ( logmar ) = 1.10.02 number of correctly read letters in the case of the pocket vision screener , the subjects were instructed to read all the letters in the middle line . \n correct response of any three letters out of the middle five in the middle line was considered to have passed the screening as more than 50% of the letters were rightly identified . the time taken to measure visual acuity \n data analysis was done using microsoft office excel 2003 ( microsoft ) and spss version 12.0 ( spss inc . ) . \n modern chart construction uses the principles of geometric progression of letter sizes , usage of letters of equal legibility , and normalization of crowding . \n the 10 sloan letters [ c , d , h , v , r , n , s , o , k , and z ] are known to have equal legibility . \n the early treatment diabetic retinopathy study ( etdrs ) charts were constructed using these ten sloan letters and logmar construction design . the pocket vision screener reported in this study \n the task for the subject would be to read the middle five letters in the middle line [ fig . 1 ] . \n the central five letters in each line were created using the letters in the 6/9 line of the etdrs charts . \n multiple combinations of these seven letter sequences were generated . from these , only those combinations that differed in their row legibility values by at most 1% were used for the construction of the chart . \n row legibility values were calculated by adding up the legibility scores of the individual letters in that line . \n the subject 's task is to read the letter ncvoz from a distance of 3 m. the box is included in this picture for clarity ; it does not appear in the pocket vision screener six versions of the screener were constructed . \n two of these had the middle line with letters chosen from the etdrs chart 1 , two with letters chosen from etdrs chart 2 and two from etdrs chart r. the two charts with the same middle line had their first and third lines interchanged [ fig \n , the left and right screeners have their first and the third lines interchanged each of the 10 sloan letters were constructed separately on a 5 5 grid using the image processing software adobe photoshop 7.0 ( adobe systems , inc , california , usa ) . \n the size of the letters was calculated to be 6.92 mm 6.92 mm for viewing at 3 m distance corresponding to a logmar visual acuity of 0.2 ( or approximately 6/9 snellen acuity ) . \n the letters were arranged using the software coreldraw 10 ( corel corporation , ontario , canada ) . \n the spacing between the rows and the spacing between adjacent letters in a row were set equal to 6.92 mm ( the letter size ) . \n the white background was extended to one letter size on all the four sides ; beyond this the screener was completely black . \n the overall size of the screener was 12 cm ( width ) 6.2 cm ( height ) . \n it is an externally illuminated chart intended to be used in a standard illumination of 130215 lux . \n the screeners were printed on a 250 gsm , matt finished paper using a laser printer with the cost of production inr 10 . \n subjects were recruited from the outpatient department of the rural eye hospital , sankara nethralaya , chennai . \n one hundred consecutive patients who could read english alphabets and who had unaided visual acuity better than or equal to 6/60 so as to exclude people with severe visual impairment . \n consecutive patients visiting the optometrist room , which was standardized for testing and who met the required criteria were included in the study . after obtaining oral consent from the subjects , \n unaided visual acuity was tested by a trained optometrist using both the newly constructed pocket vision screener and logmar visual acuity chart . \n all visual acuity testing was performed by a single examiner . for each subject , right eye was chosen as the testing eye and the other eye was occluded . \n subjects were seated at a distance of 3 m from the chart . in the case of visual acuity measurement using the logmar chart , the subjects were instructed to read from the top left and stop reading until they were not able to read anymore letters . every correctly read letter was assigned a score of 0.02 and every incorrectly read or unread letter was assigned a score of 0.00 . visual acuity ( logmar ) for each subject was determined using the formula : va ( logmar ) = 1.10.02 number of correctly read letters in the case of the pocket vision screener , the subjects were instructed to read all the letters in the middle line . \n correct response of any three letters out of the middle five in the middle line was considered to have passed the screening as more than 50% of the letters were rightly identified . the time taken to measure visual acuity \n data analysis was done using microsoft office excel 2003 ( microsoft ) and spss version 12.0 ( spss inc . ) . \n the age of the subjects ranged from 7 to 71 years ( 43 17 years ) . \n we tested the ability of the pocket vision screener to correctly identify visual acuity deficits . \n anyone who could not read correctly three letters of the middle five in the middle line were considered to have a visual acuity deficit . \n similarly , for the logmar chart , anyone who had a visual acuity logmar value > 0.24 was considered to a visual acuity deficit . \n constructing the 2 2 truth table [ table 1 ] , the sensitivity , specificity , positive and negative predictive values , and likelihood ratios of the pocket vision screener in correctly classifying the subjects were calculated [ table 2 ] . \n the positive and negative predictive values were found to be 91% and 87% , respectively . \n truth table for the measurement made with the pocket vision screener sensitivity , specificity , positive and negative predictive value , positive and negative likelihood ratio for the pocket vision screener in correctly classifying subjects the time taken by both the methods was compared using wilcoxon signed rank test as recorded times did not fall under a normal distribution . \n there was a significant difference ( p < 0.001 ) in the time taken to measure visual acuity comparing charts , with the pocket vision screener taking less time [ table 3 ] . \n screening is defined as the systematic application of a test or inquiry , to identify individuals at sufficient risk of a specific disorder to warrant further investigation or direct preventive action , among persons who have not sought medical attention on account of symptoms of that disorder . \n a screening test is said to be valid depending on the frequency with which the result of the test is confirmed by a gold - standard diagnostic procedure . \n an ideal test should have the ability to classify persons with disease as positives ( sensitivity ) and those without the disease as negatives ( specificity ) . \n sensitivity and specificity can be varied reciprocally , according to the setting , that is , the cut - off value used for further referral . above 90% of specificity \n are usually used in school vision screening programs in view of the cost involved in confirmatory examinations . \n the pocket vision screener meets these qualities as it is efficient in detecting those with visual acuity worse than 6/9 ( sensitivity ) and ruling out those who do not have defective visual acuity ( specificity ) . \n it is highly acceptable and subject - friendly , as it can be administered with ease , and consumes less time . \n population - based studies from india show that among children in the age group of 715 years , the prevalence of uncorrected visual acuity of 6/12 or worse in the better eye is 6.4% in the urban population and 2.7% in the rural population , and the prevalence of best - corrected visual acuity worse than 6/12 among the same population was 0.81% and 0.78% , respectively . \n refractive errors were the leading cause of visual impairment in 61% of eyes in rural population and 81.7% of eyes in urban population with amblyopia being the second major cause in both populations . as estimated by naidoo et al . \n when provided with appropriate refractive services and spectacles , 70% of all children in the rural areas who had baseline visual acuity worse than 6/12 and 80% of children from urban population were found to benefit . \n dandona and dandona 2006 estimated that the total number of persons with visual impairment worldwide , including that due to uncorrected refractive error was 259 million , 61% higher than the who estimate . \n 115,000 4-year trained optometrists are required to meet the demand of providing comprehensive care to all the people in the country . \n there is a huge burden of providing eye care services in india , as the number of eye care providers is insufficient for the population . \n novel initiatives such as training teachers to screen school children have shown to reduce the workload of eye care specialists . however , the false positive rates were found high among those referred by teachers . \n considering the simplicity of instructions and less time required for administration , the model of training teachers and other volunteers could be tried in future . \n low cost of production , compact size , ease of use , and the less screening time makes this screener an ideal tool for mass vision screening . \n the pocket vision screener is highly sensitive and specific and has a good positive and negative predictive value . \n therefore , this can be used as quick and accurate tool to screen subjects with visual acuity worse than 6/9 . \n the pocket vision screener is a compact and simple tool to use in addition to being very cost effective .", "role": "user" }, { "content": "aim : the aim was to construct a visual acuity chart and find its effectiveness at screening visual acuity deficits.materials and methods : two phases were involved in this study . \n construction of the screener : ten sloan letters ( c , d , h , k , n , o , r , s , v , and z ) were selected and the letters were constructed and reduced to 0.2 logmar acuity size ( 6.92 mm ) for viewing at 3 m. the screener contains three lines with seven letters in each . \n few combinations of the seven letter sequences were chosen based on the row legibility scores . \n three seven letter combinations close to the median of all combinations were selected , such that maximum difficulty score difference between the lines are < 1% . finding the effectiveness of the screener : 100 literate subjects with unaided visual acuity better than or equal to 6/60 were recruited for the study . \n unaided visual acuity was tested using both the newly constructed pocket vision screener and a logmar visual acuity chart and the time taken to measure the visual acuity using both the charts was noted.results:the mean age of the subjects was 43 17 years . \n subjects were classified as normal or deficient based on the logmar visual acuity measurement . the screener was found to have 81% sensitivity , 94% specificity . \n the positive and negative predictive values were found to be 91% and 87% , respectively . a significant difference ( p < \n 0.001 ) was found in the time taken to record visual acuity using both the charts.conclusion:the pocket vision screener can be used as a quick and accurate tool to screen subjects for visual acuity deficits , being highly sensitive , specific , and cost - effective .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: in singapore in 2005 , as part of an integrated vector - control program , laboratory - based dengue virus surveillance was established for close monitoring and investigation of the circulating dengue virus serotypes . \n samples were sent to the environmental health institute from tan tock seng hospital , which cares for 40% of all reported dengue patients in singapore , and from a network of participating general practitioners throughout the country . \n pcr to detect dengue virus rna and serotyping were performed at the environmental health institute according to its in - house real - time pcr protocol ( 7 ) . \n the numbers of dengue - positive samples serotyped were 186 in 2006 , 889 in 2007 , and 918 in 2008 , and represent 10% of the total dengue cases reported each year by the ministry of health . \n the envelope protein gene of denv ( 1,480 nt ) was amplified by reverse transcription pcr and directly sequenced by using an automated dna sequencer ( abi 3100 ; applied biosystems , foster city , ca , usa ) . \n phylogenetic analysis of denv sequences was conducted by using the maximum - likelihood method as implemented in paup * software , version 4.0b10 ( 8) , and compared with sequence data obtained from genbank . during 20062008 , \n denv-1 ( 21.7% ) and denv-2 ( 69.3% ) were the predominant serotypes throughout the study period ; denv-3 ( 7.8% ) and denv-4 ( 1.2% ) were less prevalent . in 2006 , \n the number of denv cases was relatively low , and denv-1 remained the predominant serotype after the major 20042005 outbreak . during january \n september 2006 , 75%100% of samples collected each month contained denv-1 . in early january 2007 , the predominant circulating serotype switched from denv-1 to denv-2 . \n early detection of this switch warned of a possible upcoming dengue outbreak . in response , \n the proportion of denv-2positive samples detected by pcr rose from 57.9% in january 2007 to a peak of 91.0% in july 2007 . \n this increase was accompanied by an increase in the total number of dengue cases reported by the ministry of health ; cases peaked at 432 in the first week of july 2007 . by late august \n , the number of dengue cases fell to below the warning level ( warning level = 256 cases / epidemiologic week ) as reported by the ministry of health ( 9 ) . during the switch in predominant serotype , fatality rates ( 0.32% in 2006 and 0.27% in 2007 ) and dengue hemorrhagic fever rates ( 2.4% in 2006 and 2.1% in 2007 ) \n did not differ substantially among the reported cases . during this same period of extensive surveillance , 5.2% of the samples in 2007 and 10.8% in 2008 \n our spatial analysis indicated localized emergence of denv-3 in the eastern region of the country in 2007 and in the central region in 2008 . \n enhanced control was also attempted in these areas to prevent the spread of the serotype that had been uncommon in singapore . \n trends of monthly dengue cases in singapore , 20052008 , showing a switch in predominant serotype from dengue virus serotype 1 ( denv-1 ) to denv-2 in january 2007 and cocirculation of all 4 serotypes with general dominance of denv-1 and denv-2 and lesser circulation of denv-3 and denv-4 . * from 10% of all dengue cases . \n phylogenetic analysis of denv-2 envelope gene sequences showed that the switch in predominant serotype in early 2007 coincided with a clade replacement within denv-2 . during 20002008 , 2 distinct subclades , with strong temporal topology , \n specifically , denv-2 isolates obtained before 2007 formed the subclade herein referred to as the old clade , whereas isolates obtained in 2007 and later formed the new clade with strong bootstrap support . because 1 of the denv-2 isolates sampled in 2005 clustered with the new clade but fell closer to the root of that clade , in situ evolution giving rise to denv-2 viruses that subsequently replaced the old clade viruses is highly likely . a genbank sequence that belonged to denv-2 , sampled in 2007 in vietnam , grouped within the new clade , indicating that this virus strain was not restricted to singapore and may have been circulating in this region . \n maximum - likelihood tree showing the phylogenetic relationship of a ) dengue virus serotype 2 ( denv-2 ) and b ) denv-3 from singapore and global isolates based on the envelope protein gene . \n ehi , sequence data generated at environmental health institute ; new clade , isolates obtained in 2007 and later ; old clade , isolates obtained before 2007 . \n our dengue surveillance also indicated sporadic emergence of denv-3 from localized areas throughout the country ( 6,10 ) . \n phylogenetic analysis of isolates from singapore from 2006 through 2008 identified 3 genotypes of denv-3 . \n these isolates were closely related to those found in indonesia , malaysia , philippines , thailand , saudi arabia , and cte divoire ( figure 2 ) , which suggests multiple importations of denv-3 viruses into singapore . \n analysis of denv-1 sequences showed that all except 3 belonged to genotype i and were similar to those responsible for the 2005 outbreak ( data not shown ) . \n our dengue surveillance provided early warning of the outbreak in 2007 and contributed to early activation of enhanced vector control . \n although we were unable to assess the effectiveness of the control measures , considering the regional situation in 2007 ( 11,12 ) , we believe that without these measures the dengue situation in singapore in 2007 would have been worse than or comparable to that in 20042005 . after a lull year in 2006 , dengue cases were expected to rise for a few years . \n the integrated vector control program has interrupted the dengue trend , with 7,032 cases reported in 2008 and 4,498 in 2009 . as a travel hub , \n although some become established at various levels , some develop into outbreaks and subsequently get replaced . \n it also highlights the complexity of the disease and the challenges faced by affected states that seek to understand the epidemiology for purposes of disease control . to shed further light on the complex interplay among the various factors that affect dengue transmission , \n studies are being conducted on complete genome sequences of dengue viruses , vectorial capacity of local aedes spp .", "role": "user" }, { "content": "in singapore , after a major outbreak of dengue in 2005 , another outbreak occurred in 2007 . \n laboratory - based surveillance detected a switch from dengue virus serotype 1 ( denv-1 ) to denv-2 . \n phylogenetic analysis showed a clade replacement within denv-2 cosmopolitan genotype , which accompanied the predominant serotype switch , and cocirculation of multiple genotypes of denv-3 .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: protein - protein interactions are the basis for most cellular processes , including signalling , protein synthesis , and metabolism . \n detailed knowledge of these protein networks is required in order to better understand diseases and develop adequate treatments . at present \n , protein - protein interactions are commonly investigated by yeast - two - hybrid approaches and by in vitro binding studies \n . however , these approaches are prone to false positive identifications because they do not take into account the temporal and local separations that occur in a living system . \n one tool to study protein - protein interactions in a physiological context is affinity enrichment of the protein of interest followed by detection of its binding partners using either immunodetection methods or mass spectrometry . \n in contrast , nonstringent conditions may enable the identification of more proteins , but many of these could be false positives only binding the bait protein during sample preparation . \n one approach to solve this problem is applying covalent cross - linking to intact cells and thereby stabilizing protein - protein interactions , including very weak and transient ones . \n after this fixation step , highly stringent conditions can be used during cell lysis and affinity enrichment , minimizing the risk of identifying false positives . several cross - linkers varying in spacer \n one of the shortest available cross - linkers is formaldehyde ( 2.32.7 ) , which has been used for a long time in histology and pathology to freeze the native state of tissues and cells . \n the experimental conditions used in these applications lead to a very tight network of cross - links , which prevents the precipitation of one protein of interest as required for protein - protein interaction studies . \n however , lower formaldehyde concentrations ( 0.42% instead of 4% ) and especially shorter reaction times ( minutes instead of hours ) allow the utilization of formaldehyde as a cross - linker to analyze protein - protein interactions as shown by us and others [ 58 ] . \n only closely associated proteins can be cross - linked due to the small size of formaldehyde . \n furthermore , its high permeability towards cell membranes enables cross - linking in the intact cell , without addition of organic solvents such as dimethyl sulfoxide as necessary for other cross - linkers . \n formaldehyde is also thought to allow very fast cross - linking and the stabilization of transient interactions . \n finally , formaldehyde is available in almost every laboratory at costs that amount to only a fraction of other cross - linkers . \n however , formaldehyde cross - linking is not yet an established standard method and many questions regarding the optimal experimental conditions and the usability of antibodies for pull - down of proteins after formaldehyde treatment remain . \n for example , epitopes recognized by antibodies raised against endogenous proteins could be destroyed by formaldehyde modification , which would prevent their application . \n similarly , the physiological environment of a protein of interest , and the type and extent of its interactions may also affect the experimental outcome . \n therefore , we decided to investigate different aspects of formaldehyde cross - linking in more detail using the transmembrane protein integrin 1 as a model . \n integrins are membrane spanning heterodimeric complexes that play important roles in cell adhesion and migration processes by interacting with components of the extracellular matrix \n . each integrin heterodimer is composed of one and one subunit , which are noncovalently associated . \n 18 subunits and 8 subunits are found in humans , which form 24 different heterodimers . \n the biggest subgroup with 12 members is formed by 1 containing heterodimers . before being able to bind a ligand \n , integrins have to be activated through an intracellular process termed inside - out signalling . \n for example , during platelet activation , thrombin triggers talin activation via a pathway involving protein kinase c , the small gtpase rap1 and the rap1 effector rap1-interacting molecule ( riam ) . \n activated talin then binds to the intracellular tail of the integrin and causes conformational change of the two integrin chains . \n this allows binding of extracellular ligands , which drives the cytoplasmic tail of the integrin to bind additional adaptor proteins , establishes a connection to the cytoskeleton and leads to the delivery of the external signal ( outside - in signalling ) . \n several intracellular interaction partners have been described for integrins , despite the shortness of the intracellular tail of integrins , which varies between 40 and 60 amino acids . \n 25 adaptor proteins have been reported for integrin 1 , including talin , tensin , filamin and kindlin . \n however , these interactions can not take place simultaneously , but depend on the activation status of the cell and the integrin . \n the detailed binding procedures as well as the signalling processes triggered by these are not fully understood . \n for example , talin and kindlin both interact with integrin and a crosstalk between them is assumed . \n however , it remains unclear , whether both proteins connect with the integrin at the same time or binding occurs sequentially . \n studying the interaction partners of integrins using the formaldehyde cross - linking approach , which should be able to identify transient and indirect interaction partners of proteins , may shed more light on these processes and would therefore be very valuable . in the present study , \n we report the optimization of a protocol applying formaldehyde cross - linking combined with immunoprecipitation and mass spectrometry ( figure 1(a ) ) to analyze the interaction network of integrin 1 . \n jurkat cells were grown in dulbecco 's modified medium ( gibco , high glucose ) containing 10% fetal bovine serum ( gibco ) , l - glutamine and penicillin/ streptomycin . \n this was approved by the university of british columbia research ethics board and informed consent was granted by the donors . \n briefly , whole blood was drawn from the antecubital vein into 0.15% ( v / v ) acid - citrate - dextrose anticoagulant . \n all anti - integrin 1 antibodies were monoclonal mouse anti - human antibodies provided by john wilkins ( manitoba ) . \n goat anti - mouse alexa fluor 680 was obtained from molecular probes and goat anti - mouse hrp was received from biorad . \n the integrin 1 structure was modeled on the structure of human integrin 3 using swiss model [ 17 , 18 ] and visualization was performed using the swiss - pdb viewer deep view ( http://spdbv.vital-it.ch ) . \n formaldehyde solution was obtained by dissolving 0.4% to 4% paraformaldehyde ( fisher scientific ) in pbs for 2 h at ~80c . \n the solution was filtered ( 0.22 m ) , stored in the dark at rt and discarded after 4 weeks . for cross - linking \n , jurkat cells were pelleted in a 50 ml reaction tube , resuspended in pbs and counted . \n cells were centrifuged again and resuspended to 1 10 cells / ml in formaldehyde solution . \n cells were incubated with mild agitation for 7 min at rt and then pelleted at 1800 g and rt for 3 min , resulting in 10 minutes exposure to formaldehyde . \n the supernatant was removed and the reaction was quenched with 0.5 ml ice - cold 1.25 m glycine/ pbs . \n cells were transferred to a smaller tube , spun , washed once in 1.25 m glycine / pbs and lysed in 1 ml ripa buffer ( 50 mm tris hcl , ph 8.0 , 150 mm sodium chloride , 1% np40 , 0.5% sodium deoxycholate , 0.1% sds , 1 mm edta , protease inhibitors ( complete mini , edta - free , roche diagnostics ) ) per 1 10 cells for 60 minute on ice . \n after 30 minutes , cell lysates were treated with 50 strokes using a dounce homogenizer . \n lysates were spun for 30 minutes at 20000 g and 4c to remove insoluble debris . \n control cells were treated exactly the same way , except that they were resuspended in pbs instead of formaldehyde solution . \n when platelets were used for cross - linking , ~1.5 10 cells were resuspended in 10 ml formaldehyde solution and lysed in 1 ml ripa buffer . \n the indicated amounts of antibodies and lysates were incubated for 1 h , after that 10 to 25 l protein g agarose beads ( immobilized protein g , pierce ) were added and immunoprecipitation was performed overnight . \n , lysates were precleared by incubation with the same amount of beads for 2 h before the antibody was added . \n the supernatants of the immunoprecipitations were kept for analysis and the beads were washed either twice with pbs for western blot analysis or three times with ripa buffer for mass spectrometric analysis . 4x reducing sds loading dye ( 500 mm tris hcl , ph 6.8 , 8% sds , 40% glycerine , 20% -mercaptoethanol , 5 mg / ml bromophenol blue ) was added to the beads as well as to the lysates and the supernatants and samples were incubated at either 65c or 99c for 5 min or 1020 min , respectively , before they were separated by sds page using a 8% laemmli gel . for western blot analysis \n , proteins were transferred via a semi - dry procedure on polyvinylidene difluoride membranes ( pall corporation ) , blocked for 1 h at rt with 5% milk powder in pbst ( pbs , 0.1% tween 20 ) and incubated with jb1a ( 0.1 g / ml ) overnight at 4c . \n membranes were either incubated with anti - mouse hrp or anti - mouse alexa fluor 680 ( both 1 : 10000 ) for 1 h at rt . \n membranes treated with anti - mouse alexa fluor 680 were scanned with a fluorescence scanner ( odyssey , licor ) using excitation / emission wavelengths of 700 and 800 nm , whereas signals on anti - mouse hrp incubated membranes were detected with chemiluminescence solution ( ecl , ge healthcare ) . \n briefly , gels were fixed with 10% acetic acid/10% methanol , washed with water and sensitized with 1 g / ml dithiothreitol for 15 min . \n gels were incubated in 0.1% ( w / v ) silver nitrate for 15 min and developed with 0.02% ( w / v ) paraformaldehyde in 3% ( w / v ) potassium carbonate until the desired staining had occurred . \n bands of interest in silver - stained gels were excised and destained as described . \n briefly , gel bands were incubated in a freshly prepared destaining solution ( 15 mm potassium ferricyanide/50 mm sodium thiosulfate ) until the colour disappeared , washed several times with water and ammonium bicarbonate ( ph 8.0 ) and chopped in smaller pieces . in - gel digestion was performed using standard procedures . \n briefly , samples were reduced with dithiothreitol , alkylated with iodoacetamide and digested with trypsin ( promega ) in ammonium bicarbonate overnight . \n peptides were extracted twice from the gel pieces , dried down in a vacuum centrifuge , reconstituted in 5% formic acid and stage - tip purified . separation and identification of peptides was performed by nano - hplc ms / ms on an agilent 1100 ( agilent , santa clara , ca ) coupled to an ft - icr ( ltq - ft , thermo electron corporation , waltham , ma ) using a 15 cm long , 75 m i.d . \n fused silica column packed with 3 m particle size reverse phase ( c18 ) beads ( dr . maisch gmbh , germany ) with water : acetonitrile : formic acid as the mobile phase with gradient elution . \n proteins were identified by extracting the mascot generic format ( mgf ) files from the ms data using dta super charge ( part of the msquant open source project ( http://msquant.sourceforge.net/ ) ) and searching them against the ensembl database with the x!tandem algorithm embedded in the global proteome machine ( http://www.thegpm.org/ ) . \n the protein expect score ( log(e ) ) indicates the probability of false assignment of a protein : log(e ) = 1 equates to a 1 in 10 , log(2 ) = 2 to a 1 in 100 chance of a stochastic protein assignment . \n the usage of formaldehyde as cross - linking reagent has to be evaluated in order to determine the optimal balance between highest yield of complex formation and lowest artefact generation . \n optimization has to be performed for each protein of interest , as it is dependent on the physiological environment of the protein itself and can vary for example between cytosolic and membrane proteins . \n three main parameters play a critical role during formaldehyde cross - linking : the reaction temperature , the incubation time and the formaldehyde concentration . \n the temperature dependency had been studied in our laboratory earlier and a difference between incubation at 37c and 25c could not be detected ( unpublished results ) . \n room temperature is advantageous , as it results in the most convenient and easiest approach possible . \n in addition , we chose not to increase the incubation time to more than 10 minutes , as the advantage of using formaldehyde as a cross - linker is the short reaction time it requires , which minimizes the formation of unspecific cross - links and allows the fixation of transient interactions . moreover , model studies on peptides had shown that incubation time and formaldehyde concentration are complementary . \n therefore , we decided to limit our study to the usage of different concentrations of formaldehyde in terms of our model protein integrin 1 complex . \n jurkat cells were chosen for studying integrin 1 interactions , as this human t cell line expresses high amounts of this integrin and has been used extensively for its investigation before . \n different concentrations of formaldehyde ( 0.4% to 2% ) were used to cross - link jurkat cells . \n the lowest concentration was chosen as it had been shown earlier to result in the best protein loss / cross - linking yield balance , the highest was twice as high as formaldehyde concentrations shown to be successful earlier . \n cells were lysed under stringent conditions using ripa buffer to destroy weak and noncovalent interactions , and protein amounts were determined . \n this can be explained by the formation of insoluble complexes , for example , nuclear proteins being cross - linked to dna , which were precipitated during lysis and removed in the insoluble pellet . \n this effect was visible during sample generation : lysis of nontreated cells using the stringent ripa buffer led to the release of dna , which formed a cloudy precipitate and could be easily removed . \n in contrast , a cloudy suspension was generated during lysis of formaldehyde treated cells and the pellet had a different consistency , which required a longer centrifugation period to become separated . \n consistent with this observation , nuclear proteins were not detected in the lysate by immunoblot analysis . \n however , membrane proteins were overrepresented due the loss of nuclear proteins ( data not shown ) . \n we recommend using this difference in appearance as an early indication of successful cross - linking . \n optimization of the formaldehyde cross - linking protocol involving integrin 1 required a read - out of the cross - linking efficiency , for example , the detection of a complex containing the integrin . \n formaldehyde cross - links are reversible during the standard sample preparation for sds page analysis ( figure 1(b ) ) , which includes boiling in reducing laemmli buffer , thus cross - linked complexes would not be detected under these conditions . however , by reducing the incubation temperature to 65c , cross - linked complexes are not fully destroyed and remain detectable ( figure 1(c ) ) . \n membrane protein studies by gel electrophoresis are often performed at even lower temperatures ( 3740c ) . \n initial immunoprecipitation experiments we had performed indicated that at 37c the antibodies used for pull - downs would not dissociate into their heavy and light chains ( data not shown ) . instead , \n during gel electrophoresis the intact antibodies would migrate at molecular weights that would overlap with the cross - linked complexes and therefore interfere with their detection . \n jurkat cells treated with 2% formaldehyde were used to confirm the detection of cross - linked complexes . \n lysates were incubated at 65c and 99c , respectively and analyzed by western blot using the antibody jb1a , which had been used for detection of integrin 1 in earlier studies . \n we could recognize a higher molecular weight complex containing integrin 1 in samples treated for 5 min at 65c , whereas this band was nearly undetectable after boiling for 10 minutes at 99c ( figure 1(d ) ) . \n therefore , we concluded that we were visualizing a cross - linked complex containing integrin 1 . \n this could be due to incomplete cross - linking , as the conditions applied during formaldehyde cross - linking do not lead to a high extent of protein cross - linking , leaving a large fraction of integrin 1 noncross - linked . \n alternatively , incubation at 65c may lead to partial reversal of formaldehyde cross - links and release of integrin 1 even at a lower temperature . \n equal amount of lysates of the samples generated using different concentrations of formaldehyde were analyzed by immunoblotting ( figure 2(a ) ) . \n no complex was detected in the control , in which cells were treated under cross - linking conditions but without formaldehyde . with 0.4% formaldehyde , \n a small amount of complex was detected , which increased with higher formaldehyde concentrations . at 0.8% formaldehyde , \n the amount increased slightly at higher concentrations of formaldehyde , but then settled , with no apparent difference between 1.2 and 2% . \n the signal intensities of monomeric integrin 1 and the complex were quantified , the values at 2% formaldehyde were set to 100% and relative intensities were calculated . \n these were plotted together with the total protein concentrations of the lysates to determine the optimal cross - linking parameters ( figure 2(b ) ) . \n the amount of monomeric integrin 1 did not vary significantly between the different formaldehyde concentrations , even though the amount of the complex was increasing ( figure 2(b ) ) . \n this apparent contradiction can be explained by the aforementioned observation that membrane proteins are enriched during formaldehyde treatment relative to other cellular components . \n thus , by loading equal total protein amounts in each lane , increasingly higher amounts of total integrin 1 were applied . \n unfortunately , this variation can not be compensated using loading controls , as the exact amount of each cross - linked protein can not be predicted . \n the decrease in protein concentration due to formaldehyde modification was most pronounced between 0% and 0.4% formaldehyde treatment , increased at 0.8% but stabilized at higher formaldehyde concentrations ( figure 2(b ) ) . comparing the loss of protein to the gain of integrin 1 complex ( figure 2(b ) ) implied that using a formaldehyde concentration between 1 and 2% should lead to the best cross - linking efficiency / protein loss balance , without major differences in this range . \n however , increasing the extent of cross - linking may also result in the formation of larger complexes by involving proteins that do not directly bind to integrin 1 , including the cytoskeleton . \n this would lead to the formation of more extensive , heterogeneous cross - linked complexes that would provide a larger surface to which nonspecific proteins can bind during sample processing . as a result \n , an increasing amount of abundant cytoskeletal proteins and common contaminants would be identified that would not be considered specific interactors . therefore , to minimize such apparent artefact generation , we decided to perform the following investigations using more stringent conditions by applying 0.4% formaldehyde . \n this increases the likelihood of missed identifications of specific interactors of low abundance and of interactions of low stoichiometry . \n even though higher formaldehyde concentrations would counter this effect , they would also result in more artefacts , hence differential analysis using multiple formaldehyde concentrations would still not be able to distinguish between specific interactors and artefacts . instead \n , individual follow - up experiments for each identified protein would be required to determine its specificity . \n as the focus of this study was not to obtain an extensive list of putative interactors , but rather to demonstrate the general validity of the approach , we chose lower formaldehyde concentrations and high stringency . \n users interested in maximizing the number of captured proteins should consider using higher formaldehyde concentrations instead . studying interaction partners using formaldehyde cross - linking and affinity purification \n requires the antibody to still recognize its target after reaction with formaldehyde . in our earlier studies utilizing myc - tagged proteins , \n the antibody 9e10 was shown to be suitable for formaldehyde treatment , as it still precipitated protein complexes . \n however , this has to be proven for every antibody / antigen pair before it can be used for interaction studies involving cross - linking . \n the use of a tagged , exogenous version of integrin 1 would result in additional risks coming with this approach , such as identification of false positives binding to the tag , altered protein localization , or general changes in the protein environment due to elevated expression levels . \n not all monoclonal antibodies are expected to be suitable in this technique , as some epitopes might be destroyed by formaldehyde modification of amino acids ( figure 1(a ) ) . \n we wondered whether it is possible to predict the applicability of an antibody in the formaldehyde cross - linking approach . \n therefore , we analyzed eight different and mostly well studied monoclonal anti - integrin 1 antibodies ( table 1 and figure 3 ) . \n first we wanted to know whether these antibodies were able to immunoprecipitate integrin 1 from cell lysates generated using the lysis conditions we apply during cross - linking . \n all antibodies were tested for affinity purification and were found to precipitate two integrin 1 bands between 100 and 150 kda from jurkat cell lysates ( figure 3(a ) ) . \n these two bands likely represent two differently n - glycosylated integrin 1 chains that have been detected on the cell surface of several cell types . \n in contrast to our results , meng et al could not detect the low - mass integrin 1 in jurkat cells , but they only investigated the cell membrane whereas we precipitated integrin 1 from whole cell lysates . \n . a closer look at the known properties of the anti - integrin 1 antibodies revealed that five of them had been shown to stimulate integrins when added to living cells , while two showed inhibitory character ( table 1 ) . \n however , as we were planning to use these antibodies for precipitation of integrins from cross - linked and thereby fixed cells , these properties should not affect our experiments . \n more importantly , the epitopes of some of these antibodies are known and located at very different positions in the extracellular part of the protein : n29 and jb1a detect continuous peptide sequences close to the protein n - terminus ( figure 3(b ) ) . \n in contrast , b3b11 and jb1b detect continuous sequences at the opposite end of the extracellular part of integrin 1 ( figure 3(b ) ) , where also the discontinuous epitope of 2c18 is found . \n b44 is known to recognize a different part of the protein than the other antibodies but the precise epitope is unknown . since the b44 antibody is working in immunoblotting experiments , its epitope is expected to be composed of a continuous sequence . \n in contrast , 3s3 can not be used for immunoblotting indicating a discontinuous epitope . \n we further modelled the integrin 1 structure on integrin 3 to gain insight into the three - dimensional location of the known epitopes ( figure 3(c ) ) . as expected \n additionally it is known that the epitopes of n29 and b44 are hidden in the inactivated form of integrin 1 as on some cell lines they can only detect the receptor after it had become activated . to assess \n whether the antibodies would also be able to work after formaldehyde treatment , we had a closer look at the epitope sequences , which are known for four of them ( figure 3(b ) ) . \n it had been shown that the amino acids , which are formaldehyde - modified first during the short incubation times used under cross - linking conditions , are lysine , cysteine and tryptophan . \n the epitopes of n29 and jb1a are composed to a higher extent of these amino acids ( 20 and 30% ) , compared to 7% and 12% for b3b11 and jb1b , suggesting that n29 and jb1a are less likely to work after formaldehyde treatment . \n our next step was to determine whether the antibodies found to precipitate integrin 1 in the previous section can detect and pull down the integrin 1 complex . \n cells were lysed and the lysates were used for an immunoprecipitation using the antibody jb1b and a control pull - down which was performed without an antibody ( figure 4(a ) ) . \n the higher molecular weight complex containing integrin 1 was only detected in formaldehyde treated cells and was only precipitated when the antibody was added . \n no complex was detected in the supernatant of the immunoprecipitation , indicating its complete pull - down . \n furthermore , no loss in total integrin 1 precipitation was observed , indicating that formaldehyde treatment did not destroy the jb1b epitope . \n this had been expected , as the epitope does not contain many of the easily modifiable amino acids . as a next step , \n all of the other antibodies were used to precipitate integrin 1 from formaldehyde treated and non - treated jurkat cells ( figure 4(b ) ) . \n all of them were able to precipitate the target protein even after formaldehyde treatment , indicating that none of their epitopes was destroyed in such a way that it would prevent precipitation . even for n29 and jb1a , whose epitopes contain a high percentage of easily modifiable amino acids , no fundamental loss in integrin 1 precipitation was observed . \n however , not all antibodies were equally able to precipitate integrin 1 containing complexes : b3b11 , jb1a and 3s3 precipitated the complex completely , since no integrin 1 was detected in the high molecular range of the supernatant \n . only partial precipitation of a high molecular weight complex was observed using the antibodies 2c18 and 6s6 , where part of the complex was detected in the supernatant of the precipitation . \n as these antibodies were able to precipitate integrin 1 of formaldehyde treated cells , it is unlikely that their epitopes were destroyed during the process . \n however , as mentioned earlier n29 and b44 have both been shown to detect activated integrin 1 on cells , whereas their epitopes are disguised on non - activated cells . \n in contrast , cross - linking preserves the conformation and therefore a non - activated complex would be undetectable and not precipitated by these two antibodies . on the other hand , they could be able to precipitate an activated complex which in turn would not be recognized by some of the other monoclonal antibodies . \n this limitation of antibody usage does not only apply to formaldehyde cross - linking , but restricts every approach where protein complexes are precipitated by antibodies , including the traditional coimmunoprecipitation method which uses gentle lysis conditions to preserve protein interactions . \n finally we asked whether a higher degree of modification induced by higher concentrations of formaldehyde would impede the precipitation of integrin 1 using the antibody jb1b . \n therefore we tested the ability of jb1b to pull down complexes from cell lysates , which were obtained after treatment of jurkat cells with varying formaldehyde concentrations . \n jb1b was able to precipitate integrin 1 and the complex regardless of the formaldehyde concentrations applied , which was shown by analysis of the pull - downs as well as the supernatants of the immunoprecipitations ( figure 4(c ) ) : no protein was detected in the supernatants , whereas integrin 1 was detected in the range of the monomeric protein and the high molecular weight complex in the immunoprecipitations . \n we concluded that jb1b is the most universal of the anti - integrin 1 antibodies we had tested , and therefore the most useful for formaldehyde cross - linking . \n western blot analysis had shown that we precipitate a high molecular weight complex containing integrin 1 after formaldehyde treatment . \n as the other components of this complex were unknown to us , we used mass spectrometry to identify them . \n the integrin 1 complex was precipitated by jb1b , separated by sds page and visualized by silver staining ( figure 5(a ) ) . \n the indicated band was excised , in gel digested and analyzed by lc - ms / ms . \n using jurkat cells we performed this experiment in several independent repeats , and detected integrin 1 in every sample ( table s1 ) . \n the receptor formed by these integrins is vla-4 ( very late antigen 4 ) , a known receptor found on t cells and a high abundant integrin on jurkat cells . \n two of these experiments also allowed the identification of additional proteins ( table 2 ) . \n the listed proteins were not detected in control experiments using either non - formaldehyde treated cells or immunoprecipitations performed without the antibody when analysing gel bands at masses corresponding to the integrin 1 containing complex . of these additionally identified proteins , integrin 6 \n is known to form a receptor termed vla-6 together with integrin 1 on t cells , which has not been detected in jurkat cells before . \n two additional integrin subunits were detected only in dataset 2 : integrin 5 ( log(e ) = 36.4 ) and 1 ( log(e ) = 1.7 ) . \n integrin 5 had been demonstrated to be expressed together with integrin 1 on jurkat cells , whereas integrin 1 is known to form a collagen - recognizing receptor with integrin 1 on endothelial cells . \n even though only few peptides of each protein were sequenced , the identification of the integrin subunits is reliable as they do not share high homologues sequences and all sequenced peptides were unique for each integrin . the other identified proteins are not known to interact directly with integrin 1 . as a member of the cytoskeleton , actin \n is intertwined with integrin function and associated with integrins through adaptor proteins such as talin . \n furthermore actin is a highly abundant protein and its identification has to be judged carefully . \n the same is true for gapdh and heat shock protein hsp 90 , which are both abundant proteins and frequently found in immunoprecipitations . \n thus we can not exclude that these proteins are non - specific background , even though they were not detected in the control samples . as formaldehyde cross - linking \n could also occur with abundant proteins that colocalize but have lower binding affinity to integrin 1 , this may explain the presence of abundant proteins . \n alternatively , proteins that do not colocalize but show medium to high affinity may form a non - cross - linked complex in the lysate that is sufficiently stable not to be destroyed by the incubation temperature of 65c that is applied prior to gel separation . \n this scenario may also be true for most of the other proteins ( desmoglein-1 , filaggrin-2 , junction plakoglobin and c1orf68 ) , which are highly expressed in skin cells . \n these could be contaminants similar to keratins ( which were removed before data interpretation ) occurring during sample preparation . \n the last identified protein arginase-1 is found in the liver and plays an important role in arginine metabolism , a connection to integrin 1 is not known . on the other hand , formaldehyde cross - linking would also stabilize interactions between two proteins that do not directly interact but have a common binding partner . \n this indicates that the precipitated complex is mostly in an inactive state , where the two integrin chains form a stable and very compact complex and no adaptor proteins are bound to the intracellular tail . \n this matches our earlier observation that n29 and b44 , which were shown to be unable to detect inactive integrin 1 , did not precipitate this complex . \n however , talin-1 was identified with high confidence ( log(e ) = 94.9 ) in one experiment ( dataset 2 ) indicating the ability to precipitate integrin 1/adaptor complexes using our approach , provided the integrin 1 on jurkat cells is activated . \n all our results imply that most of the integrin 1 found on the jurkat cells is not activated , which is in contrast to an earlier study where jurkat cells have been shown to express constitutively active integrin 1 . however , it has to be considered that cell lines change their behaviour over time , thus it might be that the jurkat cells used by them and by us differ in this aspect . \n in addition to our studies using jurkat cells , we wanted to apply our approach also to a different and physiologically more relevant system , and therefore used human platelets . \n platelets express high amounts of integrins , which play an important role in platelet aggregation . \n even though integrin 1 is not the most abundant integrin found on platelets , it forms three different receptors ( 21 , 51 , 61 ) and is involved in platelet adhesion . \n human platelets were treated with and without formaldehyde and the antibody jb1b was used to precipitate integrin 1 from the lysates . \n in addition to the monomeric protein , a high molecular weight complex was detected in immunoblotting experiments , which was only visible after formaldehyde treatment ( figure 5(b ) ) . \n we identified the contents of the complex precipitated by jb1b from human platelets by mass spectrometry ( figure 5(c ) , table s2 ) . \n furthermore , the integrins 6 and 2 , which are known to form heterodimers with integrin 1 on platelets , were identified . \n thrombospondin-1 , a known ligand of the integrin receptor 61 , was also detected in the integrin 1 complex . as thrombospondin-1 is \n also the most abundant protein found in the -granules of platelets , its identification may be merely due to its high abundance in the platelet lysate . \n similarly , integrin iib does not form a heterodimer with integrin 1 , but together with integrin 3 forms glycoprotein iib / iiia , the most abundant platelet receptor . \n integrin 3 was only detected in dataset 2 ( log(e ) = 40.2 ) , however , the presence of both of these proteins could be solely due to their high presence in the platelet lysate as well . \n on the other hand we can not exclude that integrin 1 interacts with one or both of these integrins forming multi - heterodimers . \n the identification of immunoglobulin heavy chain c is assumingly due to the immunoprecipitation , whereas hornerin and filaggrin-2 are both proteins expressed in the skin and could be contaminants caused during sample preparation . \n three proteins which are known to interact with integrin 1 were only detected in dataset 2 : integrin 5 ( log(e ) = 1.8 ) , talin-1 ( log(e ) = 142.2 ) and kindlin-3 ( log(e ) = 18.5 ) . \n integrin 5 is known to form the receptor vla-5 with integrin 1 . with the detection of this chain \n the identification of the adaptors talin-1 and kindlin-3 indicates again that we are able to precipitate integrin 1/adaptor protein complexes . \n however , these experiments were performed on platelets which were not intentionally stimulated , thus we do not expect high amounts of activated integrin 1 on these cells . \n stimulation can nonetheless occur to a low degree during platelet preparation , which explains the detection of talin-1 and kindlin-3 in one of the samples . \n using the transmembrane integrin 1 complex as a model , our study addressed several critical factors in the formaldehyde cross - linking procedure and provides a practical guide to the optimization of such experiments . by modifying sds page sample preparation conditions \n , we could detect an additional formaldehyde generated , high - molecular weight band containing integrin 1 by immunoblot analysis . \n lc - ms / ms analysis showed that this complex was mainly composed of integrins . several integrin subunits known to form heterodimers with integrin 1 could be detected in two different systems , jurkat cells and human platelets ( table 4 ) . \n the appearance of a broad band on the type of gel we had chosen did not provide any insights into heterogeneity and molecular weight of the corresponding integrin complex(es ) . \n indeed , the band could have arisen from a single , multi - integrin complex containing all of the identified proteins , albeit the presence of several distinct complexes with similar molecular weight resulting in overlapping bands is more likely . \n . one major focus of this study was to systematically test the applicability of monoclonal antibodies in precipitating formaldehyde treated endogenous , nontagged proteins . \n two out of eight antibodies were expected to be less likely to work in precipitating integrin 1 from formaldehyde treated cells , since their epitopes contained amino acids that are known to be susceptible to formaldehyde modification . \n however , we could not detect any difference in precipitation , indicating that destruction of epitopes is not an overwhelming problem in the formaldehyde cross - linking procedure at least for the panel of antibodies we had tested . \n two antibodies , which had been shown before to recognize only activated integrin 1 , did not pull - down the complex probably due to hidden epitopes in the complex . \n this finding , together with the observation that the analyzed complexes were mainly composed of integrin and chains , indicates that the majority of integrin 1 containing heterodimers found on jurkat cells and human platelets are in an inactive state . \n however , in two experiments out of four we could identify talin-1 , which is an adaptor protein that binds activated integrin 1 . \n this suggests that formaldehyde cross - linking is a promising tool to study integrin activation and regulation . in future experiments \n jurkat cell lines or platelets will be stimulated deliberately and the composition of the integrin 1 complexes will be analyzed . a quantitative approach based on silac or itraq labelling \n will then be applied to distinguish non - activated and activated integrin 1 and to allow timecourse studies . by testing different formaldehyde concentrations for cross - linking \n , we realized that the balance between yield of cross - linked complex and the loss of protein was shifted in the case of integrin 1 compared to earlier studies : whereas 0.4% formaldehyde had been established as optimal concentration for studying myc - tagged soluble protein earlier , 1% formaldehyde seemed to be more suitable for integrin 1 . \n while we used 0.4% formaldehyde for the current studies in order to minimize artefact generation , higher formaldehyde concentration may be used for future investigations . \n indeed , varying the formaldehyde concentration is an excellent means not only to balance yield and protein loss , but also to distinguish direct and indirect interaction partners of a protein . \n the multistep protocol for the optimization of formaldehyde cross - linking described here can be applied to any protein of interest . \n while the formaldehyde concentration is the most important variable that has to be optimized for each protein , detection of a formaldehyde cross - linked complex via western blot analysis simplifies this process . \n in addition , the application of antibodies for immunoprecipitations of modified proteins has to be monitored carefully , and the possibility that they do not recognize their antigen anymore has to be considered at all times . if these points are taken into account , however , formaldehyde cross - linking paired with immunoprecipitation will be a very powerful and reliable method to study protein - protein interactions , especially weak and transient ones , that can be established as a routine method in any laboratory .", "role": "user" }, { "content": "formaldehyde cross - linking of protein complexes combined with immunoprecipitation and mass spectrometry analysis is a promising technique for analysing protein - protein interactions , including those of transient nature . \n here we used integrin 1 as a model to describe the application of formaldehyde cross - linking in detail , particularly focusing on the optimal parameters for cross - linking , the detection of formaldehyde cross - linked complexes , the utility of antibodies , and the identification of binding partners . \n integrin 1 was found in a high molecular weight complex after formaldehyde cross - linking . \n eight different anti - integrin 1 antibodies were used for pull - down experiments and no loss in precipitation efficiency after cross - linking was observed . \n however , two of the antibodies could not precipitate the complex , probably due to hidden epitopes . \n formaldehyde cross - linked complexes , precipitated from jurkat cells or human platelets and analyzed by mass spectrometry , were found to be composed of integrin 1 , 4 and 6 or 1 , 6 , 2 , and 5 , respectively .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: a 27-year - old male patient was referred to the department of prosthodontics at our institution . \n the patient complained of facial asymmetry and poor looks due to loss of the right eye . \n the surgical intervention had been carried out when the patient was 5 months old ; thereby the growth was retarded . \n the facial asymmetry was apparent as the anophthalmic defect included the right orbit and extended laterally along the outer canthus of the eye , toward the temporal region as well along the malar eminence toward the zygomatic arch . \n the patient underwent a computed tomography scan on basis of which a stereolithographic model was fabricated . a mock surgery on the stereolithography model [ fig . \n 1 ] revealed optimal bone thickness along the inferolateral orbital rim composed of zygomatic bone while the lateral aspect of superolateral rim composed of frontal bone showed moderately optimal bone in terms of thickness and density . \n stereolithography model with pilot drill orientation and surgical template a surgical stent was fabricated as per the mock preparation . after obtaining \n two intraoral dental implants were placed depending on the availability of the bone at the defect site . a 3.75 mm 10 mm implant \n was placed in inferolateral region and 3.75 mm 8 mm implant was placed in superolateral region [ fig . 2 ] . \n a healing period of 4 months was given following which the extra oral radiographs - posteroanterior waters and lateral cephalogram [ fig . \n a metal framework was cast to attach it to the implant abutment with the magnetic keepers embedded in it [ fig . 5 ] . \n implant placement along the superolateral and inferolateral orbital rim extraoral radiographs - cephalogram and posteroanterior waters view showing position of implants facial moulage and direct implant level impression retentive assembly - pattern and casting with embedded keepers and cemented indigenous samarium cobalt magnet trial of metal sleeve - retentive assembly and acrylic shim with magnets aligned with their keepers sculpted wax pattern trial in front view and lateral view pretreatment and posttreatment photograph of the patient the evaluation of the final prosthesis showed excellent retention and stability with facial expressions and head movement . \n the patient was extremely pleased with the final outcome , and there was also a marked improvement in his social interaction and self - esteem . \n cotton buds , an interspace toothbrush with soft bristles and floss were the advised cleaning aids . \n after the orbital resection , the ophthalmic surgeon may opt to do the surgical reconstruction . \n the surgical reconstruction has limitations in age , the medical condition , remnant tissue , postradiation status of tissues , and esthetics . \n surgical reconstruction creates a patch on the defect , and all the raw areas are closed . \n in such cases , spectacles , adhesives , and osseointegrated dental implants may be the choice for retaining the prosthesis . \n however , with spectacles and adhesives , the patient may lose confidence since they may not hold the prosthesis firmly to the skin . \n in addition , there are few limitations with spectacle retained prosthesis that spectacles ever being removed in public . \n . it may be beneficial to have a little amount of defect depth to accommodate the prosthesis bulk . \n the surgeon may retain small defect portion after reconstruction to accommodate the prosthesis bulk . considering the size of the defect and economic constraints , a novel design of using \n this assembly consisted of keeper bar and dental magnets which are ordinarily available for prosthesis use along with an indigenous samarium - cobalt magnet . \n the authors certify that they have obtained all appropriate patient consent forms . in the form the patient(s ) \n has / have given his / her / their consent for his / her / their images and other clinical information to be reported in the journal . \n the patients understand that their names and initials will not be published and due efforts will be made to conceal their identity , but anonymity can not be guaranteed . \n the authors certify that they have obtained all appropriate patient consent forms . in the form the patient(s ) \n has / have given his / her / their consent for his / her / their images and other clinical information to be reported in the journal . \n the patients understand that their names and initials will not be published and due efforts will be made to conceal their identity , but anonymity can not be guaranteed . \n \n ", "role": "user" }, { "content": "orbital defects can result from cancer , birth anomalies , or trauma leading to an onslaught of problems in the function and psyche of the patient . \n these defects are restored by surgical reconstruction and followed by placement of orbital prosthesis for cosmetic makeup . \n the use of dental implants in retaining orbital prosthesis improves patient acceptance of the prosthesis owing to better retention and stability than conventional adhesive retained prosthesis . \n this case report describes a custom - made magnetic retentive assembly anchored by a dental implant which offers the orbital prosthesis the simplicity of self - alignment and ease of use .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: a 13-year - old male presented to the local emergency department ( ed ) with a 3-day history of worsening left arm pain refractory to non - steroidal anti - inflammatory medications ( nsaids ) . \n plain radiographs of the humerus were reportedly negative for any acute bony abnormality , and the patient was discharged on more nsaids . upon arrival in our emergency department \n , the patient appeared jaundiced and in moderate distress , complaining of right upper quadrant abdominal pain . \n vital signs were remarkable for a maximal temperature of 38.0 c and a sinus tachycardia at 103 beats / min . \n review of systems was positive for nausea . on physical exam , the medial aspect of the left proximal upper extremity was exquisitely tender to palpation from the elbow to the mid - axilla . \n the right upper quadrant and epigastrium were moderately tender to palpation without guarding or rigidity , and the liver edge was palpable 3 cm below the costal margin . \n laboratory values were remarkable for a wbc of 5.210/l with 92% neutrophils , platelet count of 7310/l , alt 126 iu / l , ast 133 iu / l , total bilirubin 8.0 mg / dl , and direct bilirubin 5.4 mg / dl . \n duplex ultrasound of the left upper extremity revealed occlusive thrombus in the cephalic vein extending from just above the antecubital fossa to the origin of the subclavian vein . \n chest radiography demonstrated focal infiltrates in the left lung ( fig . 1 ) . \n heparin was initially withheld due to the low platelet count and superficial location of the thrombus , and the patient was admitted to the general pediatric ward . \n 566465 mm ( 9696 dpi ) ap cxr showing mild diffuse bilateral pulmonary infiltrates . \n 566465 mm ( 9696 dpi ) shortly after admission , the patient became acutely hypoxic , with oxygen saturation of 77% on room air . \n he was transferred to the pediatric intensive care unit and stabilized with noninvasive ventilation and intravenous fluids . \n emergent ct scan of the chest demonstrated a y - shaped filling defect involving two segmental branches of the right lower lobe indicative of acute pulmonary embolism . \n the patient was subsequently anticoagulated with low molecular weight heparin and started on broad - spectrum antibiotics . \n blood cultures grew methicillin - sensitive staphylococcus aureus ( mssa ) , and antibiotic coverage was adjusted accordingly . despite anticoagulation and antibiotic administration , the patient s clinical status failed to improve . on hospital day 5 , mri of the left upper extremity showed a focal area of cortical destruction on the lateral aspect of the proximal humerus with a 2.60.83-cm fluid collection on the anterior aspect ( fig . 2 ) . \n the patient underwent operative exploration during which a subperiosteal soft tissue abscess was discovered anterior to the humeral metaphysis . \n after intravenous antibiotic administration and extensive physical therapy , he was discharged from the hospital in stable condition . \n 2mri of the left upper extremity demonstrating focal cortical destruction on the lateral aspect of the proximal humerus ( white arrow ) and a 2.60.83-cm fluid collection anteriorly ( black arrow ) ; 279123 mm ( 9696 dpi ) mri of the left upper extremity demonstrating focal cortical destruction on the lateral aspect of the proximal humerus ( white arrow ) and a 2.60.83-cm fluid collection anteriorly ( black arrow ) ; 279123 mm ( 9696 dpi ) a 15-year - old male presented to the ed complaining of left thigh pain , shortness of breath , and chest discomfort . \n two weeks before , he had been seen in an outside ed after sustaining scrapes to his knees after a fall . \n the initial injury occurred during an indoor ice hockey game , with the abrasions healing over 2 days . at that time , radiographs of the knees were reportedly normal . \n the patient was dismissed on nsaids and crutches for weight - bearing as tolerated . despite the apparent healing , \n again the patient was evaluated and discharged , this time with narcotics and non - weight - bearing instructions . over a few days he worsened , \n pain confined him to bed , and he developed pleuritic chest pain , low grade fever , chills , a sore throat and a nonproductive cough . \n his mother brought him to our ed for his third acute care visit in 3 weeks . \n vital signs were significant for a temperature of 38.8 c , pulse of 155 beats / min , and respiratory rate of 24 breaths / min with room air oxygen saturations of 88% . \n bilateral vesicular breath sounds , but no wheezing or crackles were noted on auscultation . his peripheral skin exam was normal without rash , swelling , cyanosis , and atraumatic . \n he did complain of hypesthesias of the left thigh , which limited exam of the thigh , and no crepitus was found . \n his pulses were present and symmetric in the lower extremities , but capillary refill was decreased , and no signs of veno - occlusive disease were evident . \n laboratory values revealed a wbc of 16.710/l , platelet count of 1210/l , bun of 64 mg / dl , creatinine of 2.4 mg / dl , and a d - dimer greater than 2,000 ng / ml . \n cxr showed mild diffuse bilateral pulmonary infiltrates , and the left hip film demonstrated a vague mottled lucency in the intertrochanteric region ( fig . \n duplex ultrasound of the left lower extremity was negative for deep vein thrombosis ( dvt ) , but soft tissue changes noted around the left common femoral vein were concerning for subcutaneous air . \n bedside transthoracic echo was negative for signs of right ventricular strain . computed tomography of the chest to exclude pulmonary embolism ( pe ) \n ed differential diagnosis included dic without rash , heparin - induced thrombocytopenia , pneumonic process or pe versus sirs secondary to an infectious process of uncertain etiology . \n the patient was aggressively resuscitated with intravenous fluids , prophylactically anticoagulated and initiated on broad spectrum antibiotics after blood cultures were obtained in the ed . \n 3ap radiograph of the left hip showing a vague , mottled lucency in the intertrochanteric region of the left femur suggestive of intraosseous gas ( white arrow ) ; 465566 mm ( 9696 dpi ) ap radiograph of the left hip showing a vague , mottled lucency in the intertrochanteric region of the left femur suggestive of intraosseous gas ( white arrow ) ; 465566 mm ( 9696 dpi ) after intravenous fluid rehydration , the patient s creatinine improved to 1.2 mg / dl , and a contrast ct scan of the chest , abdomen , pelvis , and left lower extremity was obtained . \n chest ct was negative for pe , but demonstrated diffuse hazy opacification of both lungs with air bronchograms , consistent with ards . \n ct of the left lower extremity demonstrated thrombus and air within the left common femoral vein with fluid throughout the myofascial planes of the left thigh and air within the left femur consistent with osteomyelitis ( fig . 4 ) . \n repeat duplex ultrasound of the left lower extremity confirmed thrombus in the left common femoral vein . \n the patient subsequently became hypotensive with increasing respiratory distress , requiring inotropic support and mechanical ventilation lasting several days . \n 4ct scan of abdomen and pelvis with contrast demonstrating clot ( white arrow ) and air ( gray arrow ) within the left common femoral vein and within the left femur consistent with osteomyelitis . \n fluid throughout the myofascial planes of the left thigh is also seen ; 34096 mm ( 9696 dpi ) ct scan of abdomen and pelvis with contrast demonstrating clot ( white arrow ) and air ( gray arrow ) within the left common femoral vein and within the left femur consistent with osteomyelitis . \n fluid throughout the myofascial planes of the left thigh is also seen ; 34096 mm ( 9696 dpi ) after stabilization , mri of the pelvis and thighs showed extensive thrombosis of the left common femoral vein extending into intramuscular branches of the upper thigh , a 1-cm fluid collection deep within the vastus intermedius , and heterogenous signal within the intramedullary compartment of the shaft and neck of the femur indicative of intraosseous gas secondary to osteomyelitis ( fig . \n 5mri of the pelvis and thighs extensive soft tissue edema ( black arrow ) and heterogeneous signal within the intramedullary compartment of the shaft and neck of the femur indicative of intraosseous gas secondary to osteomyelitis ( gray arrow ) mri of the pelvis and thighs extensive soft tissue edema ( black arrow ) and heterogeneous signal within the intramedullary compartment of the shaft and neck of the femur indicative of intraosseous gas secondary to osteomyelitis ( gray arrow ) on hospital day 2 , the patient underwent operative irrigation and debridement , with evacuation of a large amount of purulent material followed by serial culture , incisement , and drainage of affected soft tissues , with limited resection of necrotic bone . \n tissue and blood cultures were positive for fusobacterium necrophorum , an anaerobic gram - negative bacillus . despite repeated operative \n this occasioned duplex ultrasoundography of the neck and carotids vessels , which failed to reveal evidence of thrombus formation . however , repeat left lower extremity ct demonstrated local thrombus progression necessitating thrombectomy . \n as thrombus was extracted from segments involving the deep popliteal fossa and distal common iliac vein , concern for central embolization arose again . \n a repeat chest ct demonstrated small areas of cavitation throughout the dependent infiltrates , suggesting that the infiltrates were at least partially due to septic emboli ( fig . \n eventually , the patient recovered after prolonged antibiotics and multiple debridement procedures with the involved limb salvaged intact . \n 6ct scan of the chest with contrast demonstrating posterior basilar infiltrates and small areas of cavitation in the periphery suggestive of septic emboli ( black arrow ) ; 34096 mm ( 9696 dpi ) ct scan of the chest with contrast demonstrating posterior basilar infiltrates and small areas of cavitation in the periphery suggestive of septic emboli ( black arrow ) ; 34096 mm ( 9696 dpi ) \n a 13-year - old male presented to the local emergency department ( ed ) with a 3-day history of worsening left arm pain refractory to non - steroidal anti - inflammatory medications ( nsaids ) . \n plain radiographs of the humerus were reportedly negative for any acute bony abnormality , and the patient was discharged on more nsaids . upon arrival in our emergency department \n , the patient appeared jaundiced and in moderate distress , complaining of right upper quadrant abdominal pain . \n vital signs were remarkable for a maximal temperature of 38.0 c and a sinus tachycardia at 103 beats / min . \n review of systems was positive for nausea . on physical exam , the medial aspect of the left proximal upper extremity was exquisitely tender to palpation from the elbow to the mid - axilla . \n the right upper quadrant and epigastrium were moderately tender to palpation without guarding or rigidity , and the liver edge was palpable 3 cm below the costal margin . \n laboratory values were remarkable for a wbc of 5.210/l with 92% neutrophils , platelet count of 7310/l , alt 126 iu / l , ast 133 iu / l , total bilirubin 8.0 mg / dl , and direct bilirubin 5.4 mg / dl . \n duplex ultrasound of the left upper extremity revealed occlusive thrombus in the cephalic vein extending from just above the antecubital fossa to the origin of the subclavian vein . \n chest radiography demonstrated focal infiltrates in the left lung ( fig . 1 ) . \n heparin was initially withheld due to the low platelet count and superficial location of the thrombus , and the patient was admitted to the general pediatric ward . \n 566465 mm ( 9696 dpi ) ap cxr showing mild diffuse bilateral pulmonary infiltrates . \n 566465 mm ( 9696 dpi ) shortly after admission , the patient became acutely hypoxic , with oxygen saturation of 77% on room air . \n he was transferred to the pediatric intensive care unit and stabilized with noninvasive ventilation and intravenous fluids . \n emergent ct scan of the chest demonstrated a y - shaped filling defect involving two segmental branches of the right lower lobe indicative of acute pulmonary embolism . \n the patient was subsequently anticoagulated with low molecular weight heparin and started on broad - spectrum antibiotics . \n blood cultures grew methicillin - sensitive staphylococcus aureus ( mssa ) , and antibiotic coverage was adjusted accordingly . despite anticoagulation and antibiotic administration , the patient s clinical status failed to improve . on hospital day 5 , mri of the left upper extremity showed a focal area of cortical destruction on the lateral aspect of the proximal humerus with a 2.60.83-cm fluid collection on the anterior aspect ( fig . 2 ) . \n the patient underwent operative exploration during which a subperiosteal soft tissue abscess was discovered anterior to the humeral metaphysis . \n after intravenous antibiotic administration and extensive physical therapy , he was discharged from the hospital in stable condition . \n 2mri of the left upper extremity demonstrating focal cortical destruction on the lateral aspect of the proximal humerus ( white arrow ) and a 2.60.83-cm fluid collection anteriorly ( black arrow ) ; 279123 mm ( 9696 dpi ) mri of the left upper extremity demonstrating focal cortical destruction on the lateral aspect of the proximal humerus ( white arrow ) and a 2.60.83-cm fluid collection anteriorly ( black arrow ) ; 279123 mm ( 9696 dpi ) \n a 15-year - old male presented to the ed complaining of left thigh pain , shortness of breath , and chest discomfort . \n two weeks before , he had been seen in an outside ed after sustaining scrapes to his knees after a fall . \n the initial injury occurred during an indoor ice hockey game , with the abrasions healing over 2 days . at that time , radiographs of the knees were reportedly normal . \n the patient was dismissed on nsaids and crutches for weight - bearing as tolerated . despite the apparent healing , \n again the patient was evaluated and discharged , this time with narcotics and non - weight - bearing instructions . over a few days he worsened , \n pain confined him to bed , and he developed pleuritic chest pain , low grade fever , chills , a sore throat and a nonproductive cough . \n his mother brought him to our ed for his third acute care visit in 3 weeks . \n vital signs were significant for a temperature of 38.8 c , pulse of 155 beats / min , and respiratory rate of 24 breaths / min with room air oxygen saturations of 88% . \n his peripheral skin exam was normal without rash , swelling , cyanosis , and atraumatic . \n he did complain of hypesthesias of the left thigh , which limited exam of the thigh , and no crepitus was found . \n his pulses were present and symmetric in the lower extremities , but capillary refill was decreased , and no signs of veno - occlusive disease were evident . \n laboratory values revealed a wbc of 16.710/l , platelet count of 1210/l , bun of 64 mg / dl , creatinine of 2.4 mg / dl , and a d - dimer greater than 2,000 ng / ml . cxr showed mild diffuse bilateral pulmonary infiltrates , and the left hip film demonstrated a vague mottled lucency in the intertrochanteric region ( fig . \n duplex ultrasound of the left lower extremity was negative for deep vein thrombosis ( dvt ) , but soft tissue changes noted around the left common femoral vein were concerning for subcutaneous air . \n computed tomography of the chest to exclude pulmonary embolism ( pe ) was deferred in the setting of acute renal insufficiency . \n ed differential diagnosis included dic without rash , heparin - induced thrombocytopenia , pneumonic process or pe versus sirs secondary to an infectious process of uncertain etiology . \n the patient was aggressively resuscitated with intravenous fluids , prophylactically anticoagulated and initiated on broad spectrum antibiotics after blood cultures were obtained in the ed . \n 3ap radiograph of the left hip showing a vague , mottled lucency in the intertrochanteric region of the left femur suggestive of intraosseous gas ( white arrow ) ; 465566 mm ( 9696 dpi ) ap radiograph of the left hip showing a vague , mottled lucency in the intertrochanteric region of the left femur suggestive of intraosseous gas ( white arrow ) ; 465566 mm ( 9696 dpi ) after intravenous fluid rehydration , the patient s creatinine improved to 1.2 mg / dl , and a contrast ct scan of the chest , abdomen , pelvis , and left lower extremity was obtained . \n chest ct was negative for pe , but demonstrated diffuse hazy opacification of both lungs with air bronchograms , consistent with ards . \n ct of the left lower extremity demonstrated thrombus and air within the left common femoral vein with fluid throughout the myofascial planes of the left thigh and air within the left femur consistent with osteomyelitis ( fig . 4 ) . \n repeat duplex ultrasound of the left lower extremity confirmed thrombus in the left common femoral vein . \n the patient subsequently became hypotensive with increasing respiratory distress , requiring inotropic support and mechanical ventilation lasting several days . \n 4ct scan of abdomen and pelvis with contrast demonstrating clot ( white arrow ) and air ( gray arrow ) within the left common femoral vein and within the left femur consistent with osteomyelitis . \n fluid throughout the myofascial planes of the left thigh is also seen ; 34096 mm ( 9696 dpi ) ct scan of abdomen and pelvis with contrast demonstrating clot ( white arrow ) and air ( gray arrow ) within the left common femoral vein and within the left femur consistent with osteomyelitis . \n fluid throughout the myofascial planes of the left thigh is also seen ; 34096 mm ( 9696 dpi ) after stabilization , mri of the pelvis and thighs showed extensive thrombosis of the left common femoral vein extending into intramuscular branches of the upper thigh , a 1-cm fluid collection deep within the vastus intermedius , and heterogenous signal within the intramedullary compartment of the shaft and neck of the femur indicative of intraosseous gas secondary to osteomyelitis ( fig . \n 5mri of the pelvis and thighs extensive soft tissue edema ( black arrow ) and heterogeneous signal within the intramedullary compartment of the shaft and neck of the femur indicative of intraosseous gas secondary to osteomyelitis ( gray arrow ) mri of the pelvis and thighs extensive soft tissue edema ( black arrow ) and heterogeneous signal within the intramedullary compartment of the shaft and neck of the femur indicative of intraosseous gas secondary to osteomyelitis ( gray arrow ) on hospital day 2 , the patient underwent operative irrigation and debridement , with evacuation of a large amount of purulent material followed by serial culture , incisement , and drainage of affected soft tissues , with limited resection of necrotic bone . \n tissue and blood cultures were positive for fusobacterium necrophorum , an anaerobic gram - negative bacillus . despite repeated operative irrigation and debridement of the left hip , \n this occasioned duplex ultrasoundography of the neck and carotids vessels , which failed to reveal evidence of thrombus formation . however , repeat left lower extremity ct demonstrated local thrombus progression necessitating thrombectomy . \n as thrombus was extracted from segments involving the deep popliteal fossa and distal common iliac vein , concern for central embolization arose again . \n a repeat chest ct demonstrated small areas of cavitation throughout the dependent infiltrates , suggesting that the infiltrates were at least partially due to septic emboli ( fig . \n eventually , the patient recovered after prolonged antibiotics and multiple debridement procedures with the involved limb salvaged intact . \n 6ct scan of the chest with contrast demonstrating posterior basilar infiltrates and small areas of cavitation in the periphery suggestive of septic emboli ( black arrow ) ; 34096 mm ( 9696 dpi ) ct scan of the chest with contrast demonstrating posterior basilar infiltrates and small areas of cavitation in the periphery suggestive of septic emboli ( black arrow ) ; 34096 mm ( 9696 dpi ) \n few reports in the literature have emphasized the life - threatening triad of acute osteomyelitis , deep vein thrombophlebitis , and septic pulmonary embolism . \n the sequential order in which each component of the triad develops remains controversial [ 2 , 4 , 5 ] . \n jupiter et al . were among the first to highlight the association of acute osteomyelitis and septic thrombophlebitis in children [ 4 , 5 ] . \n the additional association of septic pulmonary embolism was first described by gorenstein et al . in the context of disseminated staphylococcal infection , and subsequently in a case report by yuksel et al . \n [ 1 , 2 ] , with a literature review and recommendations for management , more recently , by nourse et al . . joint pain out of proportion to exam in a nontoxic , afebrile patient can easily lull the unwary clinician into overlooking early acute osteomyelitis . \n the delay in diagnosis or bacterial pathogenicity can lead to evolution of deep venous thrombosis , which occurred in both cases presented . \n failure to appreciate the propensity of distal deep septic thrombophlebitis to advance to central pulmonary embolic shower can paradoxically create delays in initiation of anticoagulation and may facilitate early hematogenous spread through staged surgical interventions , or potentiate the situation of tardy clot extraction as a result . \n osteomyelitis in children is typically spread hematogenously and occurs most commonly in the long bones of the lower extremities [ 6 , 7 ] . however , bony infection occurred in the upper extremity in case 1 and in the lower extremity in case 2 . in each case , relatively minor trauma had preceded the development of acute osteomyelitis . \n typical chest x - ray findings early in the course of combined pulmonary and osteal infection consist of multiple poorly defined densities predominantly in the peripheral and inferior segments of the lung . \n these findings were not well discriminated by chest x - rays in our two patients . in acute osteomyelitis secondary to s. aureus , the leukocyte count is typically normal , although associated with a left shift . \n although a leukocyte count of 16.710/l with a left shift was observed in case 2 , infection in this case occurred secondary to fusobacterium necrophorum . \n the f. necrophorum bacteria is a commensal organism of the oropharynx commonly associated with lemierre s syndrome , which is a disorder characterized by acute oropharyngeal infection with secondary septic thrombophlebitis of the internal jugular vein and metastatic infection to the lungs and joints . \n though not a primary complaint , the patient in case 2 complained of a sore throat in addition to a nonproductive cough , fever , and chills . acute pharyngeal infection may have contributed to the subsequent development of septic thrombophlebitis and septic pulmonary embolism . however , no evidence of neck vein thrombophlebitis was demonstrated in this patient . in conclusion , \n the triad of acute osteomyelitis , deep venous thrombophlebitis , and septic pulmonary embolism is a rare , but life - threatening syndrome in adolescents that requires prompt recognition and treatment . \n detection of any single component of the triad should prompt a search for the other associated disorders . \n thromboembolic burden may need to be reassessed frequently if the status of the patient worsens during supportive intensive care hospitalization . \n aggressive intervention with early antibiotic administration , anticoagulation , and surgical consultation for intervention started in the ed can be life saving .", "role": "user" }, { "content": "the triad of acute osteomyelitis , deep venous thrombophlebitis , and septic pulmonary embolism is a rare , but life - threatening syndrome in children that requires prompt recognition and treatment . \n we report two cases of acute osteomyelitis complicated by septic thrombophlebitis and pulmonary emboli . both patients required operative drainage to remove the septic focus . \n recognition of any one component of the triad should prompt a search for the other associated disorders . \n aggressive management with early antibiotic administration , anticoagulation , and surgical debridement can be life saving .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: melanoma of the uveal layer ( choroid , iris , ciliary body ) is the most common primary intraocular malignant tumor in adults . \n these tumors can lead to blindness , loss of the eye , and even spreading to the optic nerve and brain . \n although , for many years , the common type of treatment for ocular tumors was enucleation , other techniques such as radiotherapy have been replaced as the standard treatment to destroy the tumor as much as possible and to preserve the eye with useful vision simultaneously . \n in 1966 , stallard proposed the treatment of uveal melanomas with radiation therapy . \n as one of the most important types of radiotherapy of uveal melanomas , eye plaque brachytherapy benefits of placing radioactive isotopes such as \n 125 \n i or \n 106 \n ru on the sclera over the tumor . as an alternative powerful treatment method \n , external beam radiotherapy is based on the energy deposition of charged particles such as protons or helium ions in tissue . \n other possible methods include stereotactic radiotherapy , transscleral or transretinal local resection , and transpupillary thermotherapy . \n \n of special interest method in treatment of uveal \n the advantage of using proton beams in dose distribution in tissue and their effective role in treatment of tumors were proposed by wilson in 1946 . \n constable and koehler offered the treatment of intraocular neoplasms using low - energy proton beams . \n this method presents more advantages in comparison with brachytherapy such as lower delivered dose to the optic nerve and less side effects such as vision loss after the treatment , as well as more reliable local tumor control . \n the local energy deposition of the proton beam leads to delivering precise and uniform dose to the tumor , and low dose to healthy tissues containing intraocular and orbital structures . \n such a desirable performance in tissue which arises from physical characteristics of protons has made this method suitable for treating the small and deep tumors . \n moreover , the clinical results show about 97% local control and 90% eye retention rate after a 5 years follow up period . \n although the most ocular proton therapy is for choroidal melanomas , proton beams can also be used for treating other ocular tumors such as angioma , hamangioma , carcinoid lymphoma , conjunctival melanoma , metastic lesions , pediatric retinoblastoma ( the most common malignant tumor of the eye in children ) , and macular degeneration . \n it is found that the monte carlo is a powerful method for simulating transport of proton beams in materials , and producing a complete and precise set of data to carry out a treatment planning system [ 9 - 12 ] . \n the monte carlo based radiation transport codes model main related physical processes including coulombic energy loss , energy straggling , multiple coulomb scattering , elastic and inelastic scattering , nonelastic nuclear reactions and production of secondary particles . \n currently , one of the most attractive and advanced techniques in proton therapy is irradiation with a pencil beam of a few millimeters in diameter , named pencil beam scanning ( pbs ) [ 13 - 15 ] . \n pbs can be defined as the act of moving a proton beam for the purpose of spreading the dose deposited by a beam throughout the target volume . \n improvement of target volume coverage due to the improved geometric control of both lateral and distal fall - off in a single treatment eld , and reduction of the secondary particles production which are unavoidable due to the proton interaction with range shifter materials in the nozzle , are the most important advantages of pbs . \n in addition , in this method , individual and narrow bragg peaks can be delivered in three dimensions throughout the target volume . \n there are a variety of ways for moving the beam across the target such as scanning by mechanical motions , scanning by magnetic field variation to bend the beam trajectory , or combinations of these two methods . \n \n in simulation studies for treatment purposes , \n it is common to use a simulated water filled phantom for transporting proton beam interactions . \n however , recent studies in brachytherapy show that defining the realistic materials of the eye and their compositions have considerable effects on dosimetric results [ 19 , 20 ] . in spite of this fact , using the realistic eye materials in proton therapy \n is neglected in the related literatures [ 21 , 22 ] . \n the presented work deals with the study of the effect of defining realistic compositions of the ocular melanoma in proton therapy . \n the method is based on irradiation of weighted proton pencil beams with different energies to a simulated water filled eye phantom , and to a phantom with realistic compositions in order to cover the tumor area . besides , the spread out bragg peaks are created to extend the pristine narrow peaks to the desired target volume . \n the dosimetric results reveal the effect of defining realistic compositions in simulation studies for proton therapy . \n these phantoms consist of a sphere with 1.2 cm radius as the human eye , with a tumor located at the corner . \n the tumor is modeled as a segment of a sphere with radius of 1 cm . \n this geometry is similar to the most common choroidal uveal melanoma . a schematic figure of the simulated phantom is shown in figure 1 . \n a schematic figure of the simulated eye phantom with a tumor located at the corner of the eye . \n the rectangular voxels are considered for dose calculation in depth direction . \n in order to study the significance of using realistic tumor materials in simulations , \n two different set of materials are used . in the first model , the eye phantom \n water phantom , and is the model which is used in the eye proton therapy simulation studies up to now . in the second model , \n the tumor is filled with the realistic material and the other part of the eye sphere is filled with vitreous , which is a thick , transparent substance that fills the center of the eye . \n it is composed mainly of water and comprises about 2/3 of the eye s volume , giving it form and shape . \n we have used the realistic compositions of the tumor and vitreous presented in table 1 , which are reported in recent published work by lesperance et al . . \n elemental compositions of materials which are used in our simulation study . the data of vitreous and tumor are taken from lesperance et al.s work . \n in addition of studying the proton therapy in eye and water phantom , we have investigated the effects of defining realistic materials on spread out bragg peak ( sobp ) . \n sobp can be created by adding different bragg curves with appropriate weighting factors to provide a flat dose distribution in desired volume . \n mathematically this method can be described as follow : \n \n sobpr , d=i=1nippri , d1 \n \n where pp ( \n ri , d ) is the pristine bragg peak with range \n ri , \n i is the relative contribution of i - th peak to the sobp , n is the number of added peaks , and sobp(r , d ) is the resulting spread - out depth dose curve with range r. the weights are optimized to form an ideal , presumably uniform , dose to the desired target volume . a typical created sobp is shown in figure 2 . \n a typical created sobp with subplot weighted bragg peaks . in the presented work , \n a monoenergetic and monodirectional proton source is located in front of the tumor . for the tumor location of our choice , rotating of the eye by patient moves the tumor toward the beam path \n it will results in delivering dose to tumor and sparing other healthy tissue such as iris . \n considering this fact , the proton beams are simulated to direct parallel to the y - axis so that the tumor is the first structure which protons see . evidently , the more proton energies result in more penetration in tissue . \n considering this fact , the proton energies are chosen so that the bragg peaks cover the desired volume . \n the energies range from 22 to 32 mev in 21 steps , and two different sobps are created in both mentioned models . \n the dose is tallied as a function of depth ( in y direction ) in 0.10.10.1 mm \n 3 \n rectangular voxels . \n this method enables us to evaluate the performance of the protons in tissue in the direction parallel to the beam axis , naming depth - dose curves . \n also , dose distributions are shown by means of isodose curves in two simulated models , to estimate planar variations in absorbed dose in phantoms . in order to create the isodose curves , the whole phantom is divided in voxels with mesh tally to show a diagram of depth dose measurement at various positions in which points of equal dose throughout the beam are joined together . \n isodose curves can be used to evaluate the two dimensional dose distributions in a simulated model by irradiation of interested beam . \n the simulations and dose evaluations presented in this work are carried out utilizing the mcnpx monte carlo code . \n as mentioned earlier , the more proton energy results in more penetration in tissue , and the beam designer should consider appropriate proton energies in order to cover the whole tumor volume . in the presented section , proton pencil beams with different energies \n are irradiated to two eye models described in previous section , and the resultant bragg peaks and depth - dose curves are calculated . \n as an example of the performance of protons in depth of two models , bragg curves corresponding to two typical energies are shown in figure 3 . \n \n a profile of depth - dose curves due to the irradiation of two typical proton pencil beams to the water phantom ( solid lines ) and ocular media ( dashed lines ) which are described in materials and methods . \n the 31 mev and 23 mev proton beams are corresponding to the peaks which are formed in the more and less depths , respectively . \n \n as can be seen , for a specific energy \n , the protons penetrate more in water , while deposit less dose in comparison to ocular media . \n based on the dosimetric results , the maximum delivered dose in ocular media differs from those of water phantom by as much as 12 - 32% . \n moreover , the difference between the depths which bragg peaks occur is of special importance in the boundary of tumor and healthy tissue . in other words , if one determine the appropriate proton energy to fall a bragg peak in the deepest part of the tumor volume ( apex of tumor ) based on the simulations in a water phantom , the apex will not receive this dose in realistic media . \n considering this effect can be vital in tumors with small volume such as uveal melanoma . \n similar to the same results reported in recent brachytherapy related published papers [ 19 - 20 , 23 ] , our simulations exhibit that defining realistic materials changes the dosimetric results in proton therapy . \n it is well known that a strictly monoenergetic proton beam is unsuitable for cancer treatment due to the longitudinally narrow peak . \n rather , it is necessary to spread out the bragg peak to deliver uniform dose within the target volume , by providing a suitably weighted energy distribution of the incident beam . \n this section aims to investigate the effect of defining realistic media on uniformity of delivered dose to tumor . \n the method is based on multiplying appropriate optimized weighting factors in pristine bragg curves to cover the extended tumor target volume in each depth with the required dose in both designed models ( see eq . \n the optimized weights for all utilized pencil beams irradiated in water phantom are presented in table 2 , as well as the ocular media . \n the effect of more penetration of pristine bragg peaks in water phantom in comparison to ocular media can be seen in two sobps , too . \n the optimized weighting factors for utilized proton pencil beams in order to cover the desired volume with a uniform dose in two designed models . \n the created spread out bragg peaks ( sobp ) inside instance depths in water phantom and ocular media based on the optimized weighting factors reported in table 2 . \n \n in order to show the effect of defining realistic media \n in delivered dose in proton therapy simulations , the weighting factors optimized for water phantom are used to create a sobp in ocular media . this procedure is equivalent to using the weighted proton pencil beams for a patient obtained from irradiation of the beams to a water phantom . \n the created sobp in instance depth of ocular media using the weighting factors which are optimized for water phantom ( solid line ) , and the sobp created in water phantom using the appropriate weighting factors for water ( dashed line ) . \n the depth - dose curves reported in previous section show comparisons between the proton beam performances in realistic ocular media and water in the direction parallel to the beam axis . in order to evaluate the performance of the beams in two models , the results are figured in the form of isodose curves , which provide a demonstration of lines passing through points of equal dose . \n figure 6 is an example of these curves corresponding to irradiation of 32 mev proton beam to both models . \n these planar variations of deposited energy in two models not only agree with the results of depth - dose curves shown in figure 3 , but also confirm with this known fact that proton therapy is a convenient method to protect surrounding healthy tissue as much as possible . in other words , the proton beam effect corresponds solely to the depths which are located in the direction of beam . \n relative isodose curves due to irradiation of a 32 mev proton pencil beam to the water phantom ( red curves ) and ocular media ( black curves ) . for better resolution \n as mentioned earlier , the more proton energy results in more penetration in tissue , and the beam designer should consider appropriate proton energies in order to cover the whole tumor volume . in the presented section , proton pencil beams with different energies \n are irradiated to two eye models described in previous section , and the resultant bragg peaks and depth - dose curves are calculated . \n as an example of the performance of protons in depth of two models , bragg curves corresponding to two typical energies are shown in figure 3 . \n \n a profile of depth - dose curves due to the irradiation of two typical proton pencil beams to the water phantom ( solid lines ) and ocular media ( dashed lines ) which are described in materials and methods . \n the 31 mev and 23 mev proton beams are corresponding to the peaks which are formed in the more and less depths , respectively . \n \n as can be seen , for a specific energy \n , the protons penetrate more in water , while deposit less dose in comparison to ocular media . \n based on the dosimetric results , the maximum delivered dose in ocular media differs from those of water phantom by as much as 12 - 32% . \n moreover , the difference between the depths which bragg peaks occur is of special importance in the boundary of tumor and healthy tissue . in other words , if one determine the appropriate proton energy to fall a bragg peak in the deepest part of the tumor volume ( apex of tumor ) based on the simulations in a water phantom , the apex will not receive this dose in realistic media . \n considering this effect can be vital in tumors with small volume such as uveal melanoma . \n similar to the same results reported in recent brachytherapy related published papers [ 19 - 20 , 23 ] , our simulations exhibit that defining realistic materials changes the dosimetric results in proton therapy . \n it is well known that a strictly monoenergetic proton beam is unsuitable for cancer treatment due to the longitudinally narrow peak . \n rather , it is necessary to spread out the bragg peak to deliver uniform dose within the target volume , by providing a suitably weighted energy distribution of the incident beam . \n this section aims to investigate the effect of defining realistic media on uniformity of delivered dose to tumor . \n the method is based on multiplying appropriate optimized weighting factors in pristine bragg curves to cover the extended tumor target volume in each depth with the required dose in both designed models ( see eq . \n the optimized weights for all utilized pencil beams irradiated in water phantom are presented in table 2 , as well as the ocular media . \n the effect of more penetration of pristine bragg peaks in water phantom in comparison to ocular media can be seen in two sobps , too . \n the optimized weighting factors for utilized proton pencil beams in order to cover the desired volume with a uniform dose in two designed models . \n the created spread out bragg peaks ( sobp ) inside instance depths in water phantom and ocular media based on the optimized weighting factors reported in table 2 . \n \n in order to show the effect of defining realistic media \n in delivered dose in proton therapy simulations , the weighting factors optimized for water phantom are used to create a sobp in ocular media . this procedure is equivalent to using the weighted proton pencil beams for a patient obtained from irradiation of the beams to a water phantom . \n the created sobp in instance depth of ocular media using the weighting factors which are optimized for water phantom ( solid line ) , and the sobp created in water phantom using the appropriate weighting factors for water ( dashed line ) . see table 2 . \n the depth - dose curves reported in previous section show comparisons between the proton beam performances in realistic ocular media and water in the direction parallel to the beam axis . in order to evaluate the performance of the beams in two models , the results are figured in the form of isodose curves , which provide a demonstration of lines passing through points of equal dose . \n figure 6 is an example of these curves corresponding to irradiation of 32 mev proton beam to both models . \n these planar variations of deposited energy in two models not only agree with the results of depth - dose curves shown in figure 3 , but also confirm with this known fact that proton therapy is a convenient method to protect surrounding healthy tissue as much as possible . \n in other words , the proton beam effect corresponds solely to the depths which are located in the direction of beam . \n relative isodose curves due to irradiation of a 32 mev proton pencil beam to the water phantom ( red curves ) and ocular media ( black curves ) . for better resolution \n as a prominent method for treating localized small sized tumors such as uveal melanoma , proton therapy offers distinct advantages in comparison to the eye plaque brachytherapy . \n the presented work deals with the investigation of using realistic eye compositions on dosimetric results in proton therapy simulations . two models of the human eye were simulated for dose calculations , one contains water to be used as water phantom , and the latter contains vitreous and realistic tumor compositions . \n these models were subjected to the irradiation of 22 - 32 mev proton pencil beams to cover the desired target volume . \n the results show an incensement of 12 - 32% in maximum delivered dose in realistic ocular media in comparison to the water phantom . \n moreover , the depth - dose curves show lower penetration of protons in realistic eye model . considering the appropriate optimized weights required covering the extended tumor volume , sobps for two models \n it was found that utilizing weighting factors calculated for pristine bragg peaks in a water phantom for pristine profiles of realistic ocular media leads to disturbance the uniformity of sobp . \n the study exhibits the effect of definition of a realistic ocular media in delivered dose to tumor boundaries , as well as in creating a flat and uniform sobp in the desired volume . \n ", "role": "user" }, { "content": "background : recent studies in eye plaque brachytherapy have shown a considerable difference between the dosimetric results using water phantom and a model of human eye containing realistic materials . in spite of this fact , there is a lack of simulation studies based on such a model in proton therapy literatures . in the presented work \n , the effect of utilizing an eye model with ocular media on proton therapy is investigated using the mcnpx monte carlo code . \n methods : two different eye models are proposed to study the effect of defining realistic materials on dose deposition due to utilizing pencil beam scanning ( pbs ) method for proton therapy of ocular melanoma . the first model is filled with water , and the second one contains the realistic materials of tumor and vitreous . \n spread out bragg peaks ( sobp ) are created to cover a typical tumor volume . \n moreover , isodose curves are figured in order to evaluate planar variations of absorbed dose in two models . \n results : the results show that the maximum delivered dose in ocular media is approximately 12 - 32% more than in water phantom . also it is found that using the optimized weighted beams in water phantom leads to disturbance of uniformity of sobp in ocular media . \n conclusion : similar to the results reported in eye brachytherapy published papers , considering the ocular media in simulation studies leads to a more realistic assessment of sufficiency of the designed proton beam in tissue . \n this effect is of special importance in creating sobp , as well as in delivered dose in the tumor boundaries in proton pencil beam scanning method .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: the role of sympathetic innervation in renovascular hypertension has long been a topic of intensive investigation . \n several lines of evidence suggest that increased activity in afferents from diseased kidneys can enhance sympathetic nerve activity , facilitate the progression of blood pressure elevation , and promote hypertension - related target organ damage [ 25 ] . \n therefore , renal sympathetic nervous activity ( rsna ) has an important role in the control of renal blood flow ( rbf ) and the glomerular filtration rate ( gfr ) and can thereby influence the extracellular volume and the arterial blood pressure [ 6 , 7 ] . \n the removal of neural input through renal denervation leads to the inhibition of tubular transport ( diuresis and natriuresis ) and , under some circumstances , to a decrease in renin secretion and angiotensin ii ( ang ii ) formation . nevertheless , changes in efferent renal nerve activity independently of reflex afferent activity are essential in the onset and maintenance of hypertension in humans and in animal models [ 912 ] . \n thus , both researchers and clinicians consider sympathetic denervation to be an important goal of therapeutic interventions aimed at reducing elevated blood pressures and , more generally , at correcting or slowing down the pathologic processes responsible for disease complications . \n examples of pathologic processes secondary to intense hypertension include heart failure , renal insufficiency , and myocardial infarction [ 1316 ] . \n the two - kidney one - clip ( 2k1c ) renovascular hypertension model is dependent on ang ii , and various studies have demonstrated elevated circulating levels of ang ii with high ang ii concentrations in the cortical tissue of the clipped and nonclipped kidneys . \n it is well known that the production of ang ii is dependent on the renin release that is stimulated by increased sympathetic activity [ 1820 ] . in this model of hypertension , the inhibition of nitric oxide ( no ) synthesis results in an exaggerated increase in the systemic blood pressure and in a decrease in rbf in the nonclipped contralateral kidney . \n several studies have also demonstrated an important effect of l - arginine ( l - arg ) on different hypertension models [ 3 , 4 , 22 , 23 ] . \n therefore , the administration of exogenous l - arg could , via an increase in the production of no , restore endothelial dysfunction and reduce blood pressure in individuals with renovascular hypertension . \n the aim of the present study was to investigate the relationship between renal denervation and l - arg treatment and the contributions of these treatments to the regulation of sodium and water excretion and of map in a model of renovascular hypertension ( 2k1c ) . \n male normotensive wistar rats weighing 150170 g were obtained from the federal university of espirito santo animal house . \n the animals were housed in a temperature- and humidity - controlled room ( 25c ) with a 12 h light cycle . \n the project was approved by the institutional ethics committee for animal research ( ethics committee for the use of animals , ufes , protocol 044/2010 ) , and all experiments were conducted in accordance with the guide for the care and use of laboratory animals published by the us national institutes of health ( nih publication 85 - 23 , revised 1996 ) . \n the animals were randomly allocated into six experimental groups ( n = 8 per group ) : normotensive control ( sham ) rats , two - kidney one - clip ( 2k1c ) rats , two - kidney one - clip rats treated with l - arginine ( 2k1c + l - arg ) , denervated normotensive ( dn ) rats , denervated two - kidney one - clip ( 2k1c + dn ) rats , and denervated two - kidney one - clip rats treated with l - arginine ( 2k1c + dn + l - arg ) . \n rats underwent bilateral renal denervation to eliminate direct and reflex influences on renal hemodynamics and excretory function . under sodium thiopental \n ( 50 mg / kg , i.p . ) anesthesia , the left kidney was exposed via a flank incision . \n the adventitia surrounding the right renal artery and vein was stripped , and all visible renal nerves were cut under a surgical microscope ( d.f . \n this renal denervation procedure prevents the renal vasoconstrictor response to suprarenal lumbar sympathetic nerve stimulation , prevents the antinatriuretic response to environmental stress , and reduces the renal tissue norepinephrine concentration to < 5% of the control concentration for up to 15 days after denervation . after renal denervation , \n the flank incision was sutured , and the procedure was repeated on the opposite side to denervate the right kidney . \n then , a silver clip ( i d , 0.2 mm ) was placed around the left renal artery . \n denervated normotensive rats underwent a similar procedure with manipulation of the right and left renal arteries but without permanent placement of the clip [ 22 , 25 ] . \n immediately after the surgery , the animals received an appropriate dose of antibiotic ( 2.5% enrofloxacin , 0.1 ml per rat , i.m . ) . \n seven days after surgery , the animals were placed individually into metabolic cages , and the animals of the 2k1c + l - arg and 2k1c + dn + l - arg groups were treated with l - arginine ( sigma , st . \n louis , mo , usa ) at a dose of 10 mg / ml in the drinking water for 7 days . \n the urinary sodium content was determined by flame photometry ( micronal b262 , so paulo , sp , brazil ) and expressed as meq / day [ 22 , 25 ] . \n the systolic blood pressure was measured by tail cuff plethysmography , to determine the time of onset of hypertension , and at the end of the experiments ( figure 1(a ) ) . at the end of the initial experimental protocol ( 15 days ) \n mg / kg , i.p . ) , and a catheter made of pe-50 tubing connected to pe-10 tubing was passed through the right femoral artery . \n the catheter was threaded through the blood vessels so that it exited at the back of the neck . \n after insertion , the catheter was flushed and filled with heparinized saline ( 40 u / ml ) . \n twenty - four hours later , the map was measured in conscious , freely moving animals using a pressure transducer ( model pt 300 ; grass instruments div . , \n warwick , ny , usa ) coupled to a bridge amplifier and a digitizer ( biopac , mp100 , santa barbara , ca , usa ) . at the end of the experimental procedures , \n the rats were killed with an overdose of anesthetic , and the kidneys were removed and stored frozen ( 22c ) for later measurement of the norepinephrine concentration . \n after the acute experiments , the kidneys were removed under anesthesia and stored frozen to measure the norepinephrine concentration by fluorometric assay ( hitachi f-2000 ) . \n statistical significance was determined using one - way anova for repeated measures , followed by tukey 's test with a level of significance set at p < 0.05 . \n the systolic blood pressure ( sbp ) data were measured by tail cuff during the experimental study in all experimental groups ( sham , dn , 2k1c , 2k1c + l - arg , 2k1c + dn , and 2k1c + dn + l - arg ) . \n the baseline sbp ( time 0 ) was similar in the six experimental groups before surgery ( sham : 119.2 2.51 mmhg , n = 8 ; dn : 110.4 2.30 mmhg , n = 8 ; 2k1c : 117.6 3.6 mmhg , n = 8 ; 2k1c + l - arg : 115.4 3.2 mmhg , n = 8 ; 2k1c + dn : 117.2 2.26 mmhg , n = 8 ; and 2k1c + dn + l - arg : 115.8 3.50 mmhg , n = 8) ( figure 1(a ) ) . seven days after surgery and denervation , the sbp increased in 2k1c and 2k1c + l - arg groups ( 2k1c : 197.1 6.08 mmhg ; 2k1c + l - arg : 197.5 8.90 mmhg , p < 0.05 ) compared to sham , dn , \n 2k1c + dn , and 2k1c + dn + l - arg ( sham : 114.4 5.2 mmhg ; dn : 103.8 2.5 mmhg ; 2k1c + dn : 128 4.9 mmhg ; 2k1c + dn + l - arg : 124.2 2.7 mmhg ) . \n additionally , dn group ( 103.8 2.5 mmhg , p < 0.05 ) showed significant reduction in sbp compared to the 2k1c + dn group ( 128 4.9 mmhg ) ( figure 1(a ) ) . on the fourteenth day after l - arg treatment , the 2k1c + l - arg group ( 160 3.5 mmhg , p \n < 0.05 ) reduced the sbp compared to 2k1c group ( 204 5.8 mmhg ) and sbp remained elevated when compared to the sham group ( 119.1 1.9 mmhg ) . on the other hand , the dn group ( 108.1 3.6 mmhg , p < 0.05 ) had significantly lower sbp compared with 2k1c + dn and 2k1c + dn + l - arg groups ( 134 5.8 mmhg ; 133.1 2.9 mmhg , resp . ) \n the map values obtained on the 15th day after surgery in conscious rats are shown in figure 1(b ) . \n the 2k1c group ( 183 5.8 mmhg , p < 0.05 ) maintained high map compared with all experimental groups ( sham : 106 3 mmhg ; dn : 96 1.8 mmhg ; 2k1c + l - arg : 143 3.4 mmhg ; 2k1c + dn : 126 6.1 mmhg ; and 2k1c + dn + l - arg : 126 7.3 mmhg ) . \n similarly , 2k1c + l - arg ( 143 3.4 mmhg ) reduced map compared to 2k1c ( 183 5.8 mmhg ) and dn group ( 96 1.8 mmhg ) mbp was still reduced compared to 2k1c + dn ( 126 6.1 mmhg ) and \n 2k1c + dn + l - arg ( 126 7.3 mmhg ) groups . \n the daily mean water intake and excretion ( figure 2 ) were significantly higher ( p < 0.01 ) in the 2k1c + l - arg group ( 39.4 1 and 12.8 2 ml / day ) than in the sham and 2k1c groups ( 28 2.8 and 7.1 0.2 ml / day ; 31.7 0.7 and 8.6 0.55 ml / day , resp . ) . \n additionally , in the denervated groups , water intake and excretion ( 39 1.4 and 12.5 0.4 ml / day in the dn group ; 42.4 1.5 and 19.2 0.6 ml / day in the 2k1c + dn group ; 44.4 1.9 and 21.5 0.8 ml / day in the 2k1c + dn + l - arg group ) were significantly higher ( p < 0.01 ) than in the sham rats ( 28 2.8 and 7.1 0.2 ml / day ) . in the denervated groups \n , there were no significant intergroup differences in water intake , but the urinary excretion levels of the 2k1c + dn and 2k1c + dn + l - arg groups were significantly higher than those of the dn group . \n additionally , the 2k1c + dn group had a significantly ( p < 0.01 ) greater level of water intake ( figure 2 ) than the animals in the 2k1c and sham groups ( 42.4 1.5 versus 31.7 0.7 ; 28 2.8 ml \n / day , resp . ) and a greater level of urinary excretion than the sham , dn , 2k1c , and 2k1c + l - arg groups . \n this result was also observed for the 2k1c + dn + l - arg group ( figure 2 ) . \n the level of sodium excretion was significantly higher ( p < 0.01 ) in the 2k1c + l - arg group than in the untreated and sham groups ( 1.1 0.05 , 0.8 0.05 , and 0.72 0.02 meq / day , resp . ) . \n in addition , the treatment associated with denervation ( 1.4 0.08 meq / day ) further increased the level of sodium excretion relative to that of the other groups ( 0.94 0.06 meq / day in the dn group and 0.93 0.06 meq / day in the 2k1c + dn group ) ( figure 3 ) . \n the levels of potassium excretion were similar in all groups ( data not shown ) . \n the success of the renal denervation procedure was confirmed by the reduction of the concentration of renal tissue norepinephrine to undetectable levels in the renal - denervated groups , compared with 422 25 ng / g wet kidney weight in the normotensive control group ( sham - operated group ) . \n the present study was designed to assess the relative contribution of l - arg treatment to changes in sodium and water excretion and its influence on map when used in combination with renal denervation . \n our data provide evidence that the administration of exogenous l - arg promoted increases in sodium and water excretion and a decrease in the map , although the map was not normalized . \n the abilities of l - arg to significantly increase sodium and water excretion and to lower the map were enhanced when combined with renal denervation . \n the effectiveness of the renal denervation procedure was confirmed by the reduction of the concentration of renal tissue norepinephrine . \n a limitation of our study was not recording systemic sympathetic activity in the different groups . \n nevertheless , recording of this parameter in denervated animals is not possible . on the other hand \n , it well established the relationship of renal sympathetic activity and systemic arterial pressure level in various hypertension models . \n it has been postulated that the major factors in the development of hypertension are an increase in ang ii and endothelial dysfunction in 2k1c hypertension . \n it is suggested that a deficient production of endothelium derived no results in diminished vasodilator tone , allowing vascular resistance to increase , and this contributes to the elevated blood pressure . \n moreover , overactivity of the sympathetic nervous system ( sns ) has been implicated in the development and maintenance of essential and renovascular hypertension in humans [ 2932 ] . \n the paraventricular nucleus ( pvn ) is an important component that regulates sympathetic outflow via projections to the intermediolateral column of the spinal cord and the rostral ventrolateral medulla ( rvlm ) . within the pvn \n , ang ii enhances the sympathetic activity and blood pressure in 2k1c rats , whereas nitric oxide ( no ) has been shown to have a sympathoinhibitory effect in the pvn [ 33 , 34 ] . \n in addition , in the central nervous system , ang ii is able to increase sympathetic vasomotor tone and , therefore , increase blood pressure . \n this effect partially explains the involvement of ang ii in the pathogenesis of many experimental models of hypertension , including renovascular hypertension [ 3 , 25 ] . \n the role of sympathetic activation in the 2k1c model has long been a topic of intensive investigation . \n the renal sympathetic nerves have been identified as major contributors to the complex pathophysiology of hypertension in both experimental models and humans . \n a modest increase in the circulating concentration of ang ii , which acts on the central nervous system via at1 receptors , might contribute to nadph activation , which leads to an increase in the local production of reactive oxygen species . \n increased reactive oxygen species production causes sympathoexcitation and arterial hypertension , and the increase in oxidative stress in the brain , particularly in neurons involved in cardiovascular regulation and in the stenotic kidney , may play a major role in maintaining a high arterial pressure and sympathetic drive under conditions of renovascular hypertension . \n one of the complications of high blood pressure is the deterioration in renal function , which may lead to an overt renal insufficiency state . in this case \n , sympathetic activity appears to be involved in the pathogenesis of renal disease , given that sympathetic activation is detectable in the initial forms of this pathologic condition , when the estimated gfr is only mildly impaired . \n it is known that the modulation of renal function by rsna is pivotal in regulating the extracellular fluid volume . \n burke et al . demonstrated that the kidney function appears to be well preserved in animals that have had one kidney clipped and the blood pressure normalized by sympathetic inhibition . \n franquini et al . demonstrated that renal denervation induced an increase in urine volume and sodium excretion . \n in contrast , dibona and sawin showed that renal denervation prevents the renal vasoconstrictor response and antinatriuresis . \n these data are consistent with the results of our study , demonstrating that the removal of renal sympathetic innervation results in greater water excretion and , thus , an increase in water intake . \n the presence of a precursor of no alone increased water and sodium excretion , and when associated with renal denervation , it induced an even greater water and sodium excretion . \n previous studies in our laboratory demonstrated that , in the context of renovascular hypertension , l - arg treatment decreases the arterial pressure not only because of the already known vasodilator effects of no formation but also because there is an increase in the renal excretion of water and sodium . \n our results demonstrate that renal efferent and afferent activity play a role in the induction and maintenance of renovascular hypertension . \n treatment with l - arg demonstrates that no participates in this process ; nevertheless , its role is not crucial , as demonstrated by its inability to reverse the hypertensive state and return the blood pressure to the control level . it was also observed that these two procedures , that is , renal denervation and l - arg treatment , were not additive in nature . \n our results highlight the participation of renal sympathetic nerve activity , as one of the casual agents , responsible for the acute induction and maintenance of two - kidney one - clip renovascular hypertension .", "role": "user" }, { "content": "the purpose was to determine the role of renal nerves in mediating the effects of antihypertensive treatment with l - arginine in a renovascular hypertension model . \n the 2k1c ( two - kidney one - clip model ) hypertensive rats were submitted to bilateral surgical - pharmacological renal denervation . \n the animals were subdivided into six experimental groups : normotensive control rats ( sham ) , 2k1c rats , 2k1c rats treated with l - arginine ( 2k1c + l - arg ) , denervated normotensive ( dn ) rats , denervated 2k1c ( 2k1c + dn ) rats , and denervated 2k1c + l - arg ( 2k1c + dn + l - arg ) rats . \n arterial blood pressure , water intake , urine volume , and sodium excretion were measured . \n the 2k1c rats exhibited an increase in the mean arterial pressure ( map ) ( from 106 3 to 183 5.8 mmhg , p < 0.01 ) , whereas l - arg treatment induced a reduction in the map ( 143 3.4 mmhg ) without lowering it to the control level . \n renal nerve denervation reduced the map to normotensive levels in 2k1c rats with or without chronic l - arg treatment . \n l - arg and denervation induced increases in water intake and urine volume , and l - arg caused a significant natriuretic effect . \n our results suggest that renal sympathetic activity participates in the genesis and the maintenance of the hypertension and also demonstrate that treatment with l - arg alone is incapable of normalizing the map and that the effect of such treatment is not additive with the effect of kidney denervation .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: sjogren - larsson syndrome ( sls ) is a rare autosomal recessive , neuro - cutaneous disorder characterized by a triad of ichthyosis , spastic diplegia or quadriplegia , and mental retardation1 ) . \n seizure , short stature , developmental delay , dysarthria , and pigmentary degeneration in the macular region of the retina ( glistening white dots ) , are other findings which may be associated with this syndrome2 ) . \n most individuals with sls have leukoencephalopathy , which may contribute to its neurological signs and symptoms . \n the prevalence of sls is 1 per 250,000 individuals in sweden where this syndrome was first observed1 ) . \n aldh3a2 gene mutation is recognized as the key defect in sls , which leads to deficiency of the microsomal enzyme fatty aldehyde dehydrogenase ( faldh)4 ) . \n , faldh dysfunction leads to impaired oxidation of fatty aldehyde to fatty acid and accumulation of fatty alcohols , aldehyde - modified macromolecules , and development of high concentrations of biologically active lipids that have been assumed to be responsible for sls manifestations5 ) . with regards to faldh \n , leukotriene b4 ( ltb4 ) is a key molecule and a pro - inflammatory mediator in developing allergic diseases , especially asthma and is the substrate for the faldh enzyme6 ) \n herein , we report a case of sls with recurrent pneumonia , and asthma , probably due to increased level of ltb4 . \n as far as we are aware , this is the first report of sls associated with asthma , and recurrent pneumonia . \n a 2-year - old boy was referred to our hospital due to developmental delay , ichthyosis , asthma , and recurrent pneumonia . \n his parents were related but there was no history of asthma , and allergic disorders in his family , and close relatives . \n he had ichthyosis at birth , and mild intermittent asthma , and 2 episodes of pneumonia also were observed in his first year of life . \n he was not able to stand or walk , independently and his speech was limited to 23 meaningful words . \n acquisition of other developmental skills was mildly delayed with achieving head control and sitting without support at 5 and 12 months , respectively . \n extensive hyperkeratosis and scaling of the skin were seen particularly in the dorsum of hands , skin flexures , and lower abdomen ( fig . \n magnetic resonance imaging ( mri ) demonstrated high - intensity lesions in the deep white matter around the trigons of lateral ventricles ( fig . \n histopathology of the skin biopsy showed hyperkeratosis with keratotic plugging and parakeratosis consistent with ichthyosis . molecular genetics study utilizing sequencing of the polymerase chain reaction product using the exon - specific primers revealed a c.370 - 372 ( gga ) deletion mutation in the second exon of aldh3a2 gene in a homozygote state . \n the patient was treated , symptomatically with inhaled corticosteroid , and bronchodilator , local paraffin applicants , and rehabilitation therapy . \n sls is estimated to be observed in 1 per 100 and 2,500 patients with mental retardation and dermatologic disorders , respectively7 ) . \n the primary defect in sls is mutation of aldh3a2 gene , responsible for production of faldh , an enzyme that catalyzes the oxidation of fatty aldehydes to fatty acids . \n the accumulation of fatty acids in the skin destroys the transepidermal water barrier , and leads to ichthyosis and desquamation . \n periumbilical region , neck and flexures are , mostly affected , and face is usually spared as in our case . \n ltb4 is a potent pro - inflammatory mediator and its production is increased in allergic rhinitis , atopic dermatitis , allergic conjunctivitis , and asthma8 ) . \n asthma might ensue in sls as the result of increased level of ltb4 secondary to impaired faldh \n the diagnosis of asthma in early childhood is challenging , and is based largely on clinical judgment , assessment of symptoms , and physical findings . according to global initiative for asthma guideline the diagnosis of asthma is highly suggested in under 5-year group if frequent episodes of wheeze , nocturnal cough in periods without viral infections , and absence of seasonal variation in wheeze has occurred as did occurred in our patient9 ) . \n in addition he responded to the inhaled corticosteroid and bronchodilator and his respiratory signs and symptoms were controlled with these drugs , every time he experienced acute attacks of wheezing . \n he had past history of atopic dermatitis in neonatal period and early infancy but examination for allergic sensitization had not been performed for him . \n we did not perform bronchoscopy for our patient , so we could not report the level of ltb in bronchoalveolar lavage fluid . \n based on asthma predictive index ( api ) a positive stringent api index requires recurrent episodes of wheezing ( 3 episodes / yr ) during the first 3 years of age and one of two major criteria ( physician - diagnosed eczema or parental asthma ) or 2 of 3 minor criteria ( physician - diagnosis allergic rhinitis , wheezing without colds , or peripheral eosinophilia 4%)10 ) . \n our patient had recurrent episodes of wheezing and one major criteria of eczema and 1 minor criteria of wheezing without colds . \n recurrent pneumonia is defined as 2 episodes in a single year or 3 episodes ever , with radiographic clearing of densities between occurrences11 ) . \n the diagnosis of recurrent pneumonia in our patient was established based on the history of 2 episodes of pneumonia during a single year . \n every episode of pneumonia was diagnosed based on respiratory signs and symptoms , auscultatory findings in addition to pulmonary infiltration on chest x - ray reported as pneumonia by the radiologist . \n neurologic deficit in sls is observed with progressive delay in motor development , long tract signs , and spasticity , mostly affecting the lower limbs . \n cognitive development is slow and mild to moderate mental retardation and speech problems usually are noted12 ) . \n epilepsy is seen in 30%50% of patients , and usually develops later in childhood but our patient had no history of seizure2 ) . \n mri of brain usually shows mild to moderate brain atrophy , and retarded myelination in the anterior centrum semiovale as was observed in our patient2 ) . \n diagnosis of sls is made by the presence of the classic triad and confirmed by enzyme assay , and/or genetic study . \n analysis of ltb4 and its metabolites in urine has offered a new , noninvasive and low - cost diagnostic test6 ) . \n treatment is supportive , and includes the use of emollients , keratolytics , systemic retinoids , and rehabilitation therapy . \n other findings show that gene therapy may be a treatment option in the future14 ) . in conclusion \n , pediatricians should be aware and evaluate patients with sls for possible associated asthma , and allergic disorders .", "role": "user" }, { "content": "sjogren - larsson syndrome ( sls ) is a rare autosomal recessive neurocutaneous disorder with worldwide incidence of 0.4 per 100,000 people . \n it is characterized by the triad of congenital ichthyosis , spastic diplegia or quadriplegia , and mental retardation . \n herein we report a 2-year - old male child with sls , asthma , and recurrent pneumonia . \n sls was confirmed by a molecular genetics study that revealed a deletion mutation in the aldh3a2 gene . \n an aldh3a2 gene mutation results in dysfunction of the microsomal enzyme fatty aldehyde dehydrogenase and impaired metabolism and accumulation of leukotriene b4 , which is a key molecule and a pro - inflammatory mediator in developing allergic diseases , especially asthma . an increased level of leukotriene b4 has been reported in sls patients . as far as we are aware , this is the first report of sls associated with asthma and recurrent pneumonia . in conclusion , pediatricians should be aware of and evaluate patients with sls for possible associated asthma and allergic disorders .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: hundreds of endangered egyptian vultures ( 5 ) ( henceforth the vultures ' ) overwinter and feed at a large livestock carcass dumping site known as jorbeer in the desert of thar in northwest india ( n 2757.958 e 7322.598 ) . \n the vultures breed in the higher ranges of pakistan , afghanistan , few central asian countries , and parts of europe ( 5 ) . approximately \n 20 carcasses of stray and dairy cattle , camels , dogs , equines , and poultry offal were being dumped daily at the site during the study period . \n most carcasses originated from dairy farms , veterinary clinics , and research centers and could possibly contain residual veterinary antimicrobials . \n the dump also hosted many other avian species , migratory as well as resident vultures and eagles , and hundreds of resident stray dogs . \n fresh fecal samples were collected from roosting sites of the vultures by non - invasive means . \n a total of 25 samples were collected in two consecutive winter seasons , that is , february 2011 ( n=11 ) and march 2012 ( n=14 ) . \n all the sampled birds were apparently healthy and did not show any clinical symptoms of disease . \n the birds always existed in excess of 500 individuals , as estimated by line - transect method ; thus , the probability of duplicate sampling from a single individual was statistically insignificant ( p<0.05 ) . \n all samples were enriched in nutrient broth ( himedia , mumbai ) at 37c for 12 hours , streaked on cetrimide agar ( himedia , mumbai ) , and incubated \n the resulting colonies were streaked on nutrient agar plates ( himedia , mumbai ) and incubated at 37c for 24 hours to obtain pure cultures . \n gram - negative rods from oxidase- and catalase - positive colonies were processed further with standard biochemical tests . \n dna isolation was performed following a published protocol ( 6 ) , with some minor modifications . \n species - specific primers ( f-5 gggggatcttcggacctca 3 and r-5 tccttagagtgcccacccg 3 , product 956 bp ) were employed in a 16s rrna gene - based pcr identification ( 7 ) . \n genotypic characterization of the virulence markers exo - s , exo - u , and alg was conducted using earlier described methods ( 810 ) with the following primer sequences : exo - s ( product 504 bp ) - ( f ) 5 ctt gaa ggg act cga caa gg 3 , ( r ) 5 taa \n gtg atg cgc ctg gac tt 3 ; exo - u ( product 1,500 bp ) - \n ( f ) 5 gca gcc tat cgt gca ag 3 , ( r ) 5 gcg tgc \n agt gat tgc ga 3 ; alg ( product 313 bp ) - ( f ) 5 cgt ctg ccg cga gat cgg ct 3 , ( r ) 5 gac ctc gac ggt ctt gcg ga 3. pcr amplification of the 16s rrna gene was carried out in a 50 l reaction volume using the promega gene amplification kit ( madison , wisconsin , usa ) by mixing 10 l 5 assay buffer , 1 l f - primer ( 10 pm/l ) , 1 l r - primer ( 10 pm/l ) , 1-l dntp ( 10 mm ) , 3 l mgcl2 ( 1.5 mm/l ) , 0.25 l taq dna polymerase ( 5 u/l ) , 30.75 l deionised water , and 3 l template dna ( 25 ng/l ) . \n the pcr was performed in eppendorf mastercycler gradient ( eppendorf ag , hamburg , germany ) . \n the pcr for 16s rrna amplification involved initial denaturation at 96c for 1 min , followed by 40 cycles of 94c for 30 sec , 58c for 30 sec , 72c for 1 min , and final extension of 72c for 10 min . \n reaction volumes and concentrations of mastermix were similar for exo - s , exo - u , and alg pcrs , but the annealing temperature was 55c for 1 min . \n pcr reaction products were analyzed by electrophoretic separation on 1.2% agarose gels stained with ethidium bromide . \n subsequently , p. aeruginosa isolates were tested for in vitro antimicrobial sensitivity to 13 routinely used antimicrobials of different chemical classes by disc diffusion ( 11 ) , employing a clinical laboratory standard institute ( clsi ) protocol using the p. aeruginosa atcc 27853 strain to validate the results . \n the frequency of isolation was 32.0% ( n=25 ) as eight samples from the vultures were positive for p. aeruginosa . \n mutually exclusive exo - s and exo - u virulence factors were confirmed in five and three samples , respectively , while alg was present in all the isolates . \n all the isolates were resistant to ampicillin and susceptible to amikacin , ciprofloxacin , gentamicin , and polymyxin b. the isolates showed reduced susceptibilities to bacitracin , carbenicillin , cephalothin , colistin , kanamycin , cephotaxime , nalidixic acid , and nitrofurantoin . \n complete susceptibility to ciprofloxacin is notable , as resistance to fluoroquinolones is encoded exclusively by chromosomal genes , while resistance to beta - lactam antibiotics and aminoglycosides could be plasmid mediated ( 12 ) , indicative of the role of conjugative plasmids for acquiring resistance genes . \n these findings are significant as the vultures were without any prior therapeutic exposure to antimicrobials , and also information on mar p. aeruginosa from avian wildlife is very rare , especially from asia . \n the presence of exo - s , exo - u , and alg genes , which are important determinants of the virulence of p. aeruginosa ( 1 , 13 , 14 ) , is probably a novel finding . \n all bacteria , isolated from the vultures , internally or externally , can potentially cause horizontal disease transmission both in wildlife and humans ( 15 ) . \n the observed persistence of the potentially virulent and mar isolates in both wintering seasons , the migratory movements of the vultures , and their interaction with other species of migratory raptors at jorbeer were substantial reasons underlining the spatial and ecological efficiency of the vultures as a potential epidemiological vector of p. aeruginosa and associated resistance and virulence genes . \n these findings highlight a risk of impairing regional measures to control emerging mar and pathogenic strains of p. aeruginosa . \n moreover , because of the pathogenicity of p. aeruginosa in other raptorial species ( 4 ) and its remarkable host adaptabilities , further studies are advocated to investigate potential detrimental effects ( if any ) to these endangered vultures along with dedicated molecular studies to determine the mechanisms responsible for the acquirement of the antimicrobial resistance by the p. aeruginosa . \n ", "role": "user" }, { "content": "this study of pseudomonas aeruginosa in fecal droppings of migratory egyptian vultures ( neophron p. percnopterus ) revealed eight positive samples ( n=25 ) by a 16s rrna gene - based pcr in two consecutive winter seasons . \n disk diffusion sensitivity testing revealed three multiple antimicrobial resistant ( mar ) isolates . \n genotypic characterization showed mutually exclusive exo - s and exo - u virulence genes in five and three isolates , respectively , while the alg gene was present in all of the isolates . \n mar isolates with virulence genes were detected in both seasons . \n the egyptian vultures could potentially be vectors of pathogenic and mar p. aeruginosa , thereby affecting regional control and preventive measures .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: somatic cells can be reprogrammed into induced pluripotent stem cells ( ipscs ) by overexpression of the transcription factors oct4 , sox2 , klf4 , and myc ( oskm ) ( takahashi and yamanaka , 2006 ) . \n regardless of tissue origin , ipscs possess full developmental potential in vitro , form teratomas in vivo , and are even capable of generating all - ipsc mice after injection into tetraploid blastocysts ( zhao et al . , 2009 ) . \n their ability to contribute to all tissues makes ipscs attractive for disease modeling and for regenerative medicine . \n recently , it was reported that the differentiation propensity of ipscs reflects the tissue of origin , such that neural - derived ipscs more readily differentiate into neurons , and blood - cell - derived ipscs are biased toward the hematopoietic lineage ( bar - nur et al . , 2011 , kim et al . , 2010 , \n this tissue of origin memory has been shown to be associated with differences in epigenetic features . \n residual dna methylation marks were found at promoters in early ipscs , presumably stably silencing genes that act in specifying lineages other than the donor cell type ( kim et al . , 2010 ) . \n early passage ipscs obtained from different cell types were also found to have distinct gene expression profiles . \n some of the distinguishing genes appeared to show residual cell - of - origin - specific transcription , which was interpreted to reflect memory of the transcriptional status in founder cells ( polo et al . , 2010 ) . \n the founder - dependent transcription and dna methylation profiles were lost upon prolonged passaging of the ipscs or after treatment with chromatin - modifying drugs ( kim et al . \n different cell types also show distinct 3d chromatin structures ( dixon et al . , 2015 , rao et al . , 2014 ) , and genome topology \n chromosomes can be subdivided into topologically associated domains ( tads ) , structural units within which sequences preferentially contact each other ( dixon et al . , 2012 , nora et al . , 2012 , sexton et al . , 2012 ) . \n tads serve to physically restrain interactions of enhancers with their target gene promoters ( nora et al . , 2012 ) . \n tad organization is relatively stable during development , but contacts within tads can dynamically change between cell types ( phillips - cremins et al . , \n while some enhancer - promoter contacts seem tissue invariant , others are specifically established during differentiation , contributing to tissue - specific transcription programs ( de laat and duboule , 2013 , rao et al . , 2014 ) . \n to what degree this is also true for higher levels of structural chromatin organization is not fully understood yet , but some tads switch between genomic neighborhoods , or compartments , in a cell - type - dependent manner ( dixon et al . , 2015 , rao et al . , \n the genome of embryonic stem cells ( escs ) , for example , uniquely brings together distal chromosomal regions that are densely packed with pluripotency factors , which creates a configuration proposed to contribute to maintenance of pluripotency ( de wit et al . , 2013 ) . \n furthermore , it has been shown that the pluripotency genes nanog and oct4 make specific long - range interactions in esc and ipscs , which are lost during differentiation ( apostolou et al . , 2013 , denholtz et al . , 2013 , wei et al . , 2013 ) . \n however , little is known to what extent the overall 3d genome of somatic cells and their ips derivatives differ , how stable such differences are , and how similar the 3d configurations of ipsc and esc genomes are . here \n we show that somatic cell reprogramming is accompanied by massive changes in genome topology , which , irrespective of the cell type of origin , converge on the 3d structure of the pluripotent genome . despite this , distinct topological features separate early passage ipscs according to their cell type of origin , and these differences seem to be acquired during reprogramming in a founder - cell - dependent manner . \n to study how reprogramming of somatic cells affects nuclear organization , we used reprogrammable , oskm - inducible , mice ( carey et al . , 2010 ) . \n we generated three independent ips cell lines each from four different founder cell types , i.e. , pre - b cells , bone - marrow - derived macrophages ( m ) , neural stem cells ( nscs ) , and mouse embryonic fibroblasts ( mefs ) ( figure 1a ) . \n ipscs were established after picking of doxy - independent colonies at day 20 of reprogramming ( 15 days of reprogramming in the presence of doxy + 5 days without doxy ) and were expanded for an additional 3 passages or 20 passages to obtain early ( p3 ) and late ( p20 ) passage ips lines , respectively . \n both p3 and p20 passage ipsc lines showed characteristic esc - like morphology , expressed markers of pluripotency , as shown by immunofluorescence and fluorescence - activated cell sorting ( facs ) , and could be maintained in a transgene - independent manner ( figures 1b , 2a , and s1a ) . \n furthermore , p3 ipscs derived from each cell type gave rise to chimeras upon blastocyst injection ( figure 1c ) . \n importantly , embryoid bodies ( ebs ) obtained from the various p3 ipsc lines showed a differentiation bias toward the cell type of origin ( figure s1b ) . \n ebs derived from pre - b - ipscs and m-ipscs showed higher expression of the hematopoietic - associated genes cd45 , cd41 , itgam ( mac-1 ) , and hoxb4 , while the neuronal - associated genes nestin and pax6 were more highly expressed in ebs derived from nsc - ipscs . in contrast , the endoderm associated gene sox7 showed no such a bias ( figure s1c ) . \n the blood and neural origin bias was lost in p20 ipscs ( figure s1d ) . \n these findings confirm the tissue - of - origin memory of early passage ipscs described previously ( bar - nur et al . \n , 2011 , kim et al . , 2010 , polo et al . , 2010 ) . \n to systematically compare the transcriptomes of the four founder cell types and of their ipsc derivatives , we performed genome - wide expression analysis . \n pre - bs , nscs , ms , and mefs had highly divergent transcription profiles yet were very similar between biological duplicates ( figure 2b ) . \n we identified 13,880 unique genes that were differentially expressed ( at an fdr of 0.01 ) by the four cell types . \n reprogramming of the four somatic cells resulted in loss of tissue - specific expression programs and yielded transcriptomes that highly correlated between all ips lines and strongly corresponded to an esc - like expression pattern ( figures 2a and 2b ) . \n similarly , active enhancer profiles , as defined by histone h3 lysine 27 acetylation ( h3k27ac ) were also very different between founder cells ( creyghton et al . , 2010 , lane et al . \n , 2014 , yue et al . , 2014 ) ( figure 2d ) but became highly similar after reprogramming in all ipscs ( figures 2c and 2e ) , with cell - of - origin - specific sites having very little residual enhancer marks ( figure 2d ) . \n although expression profiles in both p3 and p20 ipscs were highly correlated , unsupervised hierarchical clustering of the transcription profiles revealed that p3 passage ipscs derived from the same cell of origin clustered together ( figure 2f ) . \n indeed , 1717 unique genes were differentially expressed ( fdr of 0.05 ) between p3 ipscs derived from different founders . \n this indicated that the cell type of origin left a mark on transcription in fully reprogrammed p3 passage ipscs . \n in contrast , p20 ipscs showed clearly reduced gene expression clustering ( figure s2a ) and only two genes with reproducibly founder - dependent differential expression ( fdr of 0.05 ) . \n this is consistent with previous reports demonstrating that ipscs transiently retain cell - type - of - origin differences in gene expression ( kim et al . , 2010 , polo et al . , 2010 ) . \n to further understand transcriptional differences and similarities between p3 passage ipscs derived from different cell types , we performed k - means clustering and identified seven clusters of genes in p3 ipscs ( figure 2 g ) . to determine whether their differential expression echoed previously established transcription patterns in the cells of origin , we calculated the correlation in expression on a gene - by - gene basis between founders and ipscs . \n for p3 ipscs the expression of genes in most clusters showed little correlation with that of the founders , with the exception of cluster 2 ( figures 2 g and s2b ) ( p < 0.001 , wilcoxon rank sum test ) . in agreement , \n 2005 ) only showed a clear enrichment of functional categories for cluster 2 , namely for genes involved in the immune system and collagen ( figure s2c ) . \n consistent with this annotation , genes in this cluster are highly expressed in m-p3 ipscs and in mef - p3 ipscs but not in nsc - derived ipscs . \n vice versa , when we clustered genes according to tissue - specific expression patterns in the founders , we also found no indications for systematic memory of cell - type - specific expression programs in the corresponding p3 and p20 ipscs ( figure s2d ) . furthermore , \n when we selected tissue - specific genes based on their > 4-fold higher expression in one of the founding somatic cell lines compared the other three , we found that none of the genes maintained this difference in transcriptional output in the corresponding ipscs . \n only when we lowered the threshold for differential expression among ipscs to 1.4-fold , a small number of genes ( 22 ) were reproducibly scored across all lineages ( 16 for m , 5 for pre - b , 1 for mef , and 0 for nsc ) as having a founder - specific expression profile . \n collectively , this showed that overall cell - type - specific expression programs were efficiently erased and replaced by esc - like transcription programs during reprogramming . \n in addition , reproducible cell - type - of - origin - specific gene expression patterns exist in p3 ipscs , although only for one gene cluster this is related to a founder - specific gene expression program . \n the remaining founder - dependent gene expression patterns in p3 ipscs appear reproducibly acquired during reprogramming , possibly as a consequence of cell - type - specific reprogramming events . to investigate how nuclear organization changes during reprogramming \n , we used a frequently cutting restriction enzyme ( dpnii ) to generate genome - wide hi - c contact maps for each of the four founder cell types and their respective p3 and p20 ipsc derivatives . \n we prepared hi - c data from two to three independent clones ( with the exception of the nsc founder , from which only one hi - c library was created ) , which we combined for each cell type , resulting in hi - c maps based on 39 - 72 m valid reads ( table s1 ) . \n we first compared the overall chromosome organization of the different cell types by partitioning the genome into regions of 300 kb and plotting all interactions between these regions as a heatmap and a correlation heatmap ( figure 3a ; table s2 ) . as expected , most interactions occurred in cis and at close distance , although many long - range contacts beyond the level of tads can be observed . \n closer inspection of the heatmaps revealed clear differences in genome folding between the different somatic cell types . \n reprogramming erased many of these tissue - specific configurations and created a 3d genome that was highly similar between all ips lines . \n previous hi - c studies have shown that chromosomal regions can be segregated into two main nuclear compartments ( lieberman - aiden et al . , 2009 ) . \n regions within the same compartment preferentially interacted with each other and were highly enriched for , respectively , active ( compartment a ) or inactive chromatin ( compartment b ) ( lieberman - aiden et al . , 2009 ) . \n we found that the distribution of genomic regions between these compartments differed strongly between the somatic lines ( figures 3a3c ) , with 28% of the genome located in a different compartment in at least one of the founders . \n this percentage is not very different from the 36% of the genome that was found to change compartments during in vitro differentiation ( dixon et al . , 2015 ) . \n genes tissue specifically residing in the a compartment showed increased expression levels in the corresponding cell type , while those tissue specifically located in the b compartment showed reduced transcriptional output as compared with that in the other tissues ( figure s3 ) . \n an example of such a gene ( ly6d ) with tissue - specific activity and corresponding nuclear location in pre - b cells is shown in figure 3d . \n for every cell type of origin , reprogramming efficiently erased the tissue - specific division of genomic regions over the a and b compartments and induced a compartment structure that is very similar to what is found in escs ( figures 3a3c ) . \n already in p3 passage ipscs , 99.9% of the genome resided in identical compartments , which increased to 99.95% in p20 ipscs . \n for example , sox2 was found to be expressed and located in the active compartment in nscs , but inactive and located in the b compartment in the other somatic cell types . \n reprogramming induced the expression of endogenous sox2 and relocated the gene to the active compartment in ipscs derived from pre - b , m , and mef ( figure 3e ) . \n genes that switched compartments during reprogramming changed their expression levels more often than genes that did not switch compartments ( figure 3f ) , with genes relocating from b to a showing an overall increase in expression , and vice versa , genes switching from a to b showing an overall reduction in expression in ipscs . a similar , albeit more subtle , correlation between expression changes and compartment switching was observed before during in vitro differentiation ( dixon et al . , 2015 ) . \n these data demonstrate that somatic founder cells generally structure their chromosomes very differently , but reprogramming induces these differences to disappear and genomes to adopt an esc - like higher order structure ( figure 3c ) . \n thus , independently of the somatic founder cell type , reprogramming into ipscs leads to a convergence of the 3d genomes to an esc - like topology . \n the pluripotent genome was previously found to have some unique topological features ( de wit et al . \n one such hallmark is the preferential long - range contacts between regions with high - density binding sites of the pluripotency factors nanog , oct4 , and sox2 ( de wit et al . , 2013 ) . to understand whether reprogramming reshapes the genome to establish this esc - specific configuration , we performed paired - end spatial chromatin analysis ( pe - scan ) , an algorithm combining chip - seq data with hi - c data ( de wit et al . , 2013 ) . \n pe - scan applied to founder cells showed , as expected , no spatial clustering of nanog- , oct4- , and sox2-rich regions . \n p3 passage ipscs , however , did show strong preferential clustering of these regions ( figures 4a and 4b ) . \n this indicates that during reprogramming chromosomes are refolded such that clusters of binding sites of pluripotency factors contact each other in nuclear space . \n for example , regions dense in binding sites of pu.1 , an essential factor for the development of immune cells , showed preferential contacts in pre - b cells but not in the other somatic cell types or in p3 ipscs , including the pre - b - cell - derived lines ( figure 4a ) . \n another interesting example is sox2 , which is expressed both in nscs and ipscs but binds to a completely different repertoire of sites in the two cell types ( lodato et al . , 2013 ) . \n pe - scan analysis revealed that the nsc - specific sox2-associated regions exclusively clustered in nscs , whereas the es - specific sox2-bound regions only did so in ipscs ( figure 4b ) . altogether , the results demonstrate that reprogramming reshapes the genome to erase somatic cell - type - specific topological features and establishes a conformation unique to the pluripotent cell genome . \n our data so far established that the relative positioning of chromosomal regions is strongly reorganized during reprogramming , raising the question whether this is also true for more local topological features such as tads . to assess how domain organization is affected by reprogramming , we annotated tads in the hi - c map from p3 passage ipscs ( table s3 , with a size range of 20.4 kb to 7.6 mb , median size 526 kb ) and compared chromatin interactions in these domains between all cell types . \n recently various reports introduced a domain score , a measure for the degree of connectivity within a tad ( chandra et al . \n , 2015 , dixon et al . , 2015 ) . for each tad we calculated this domain score as the fraction of intradomain contacts over its total number of cis contacts ( figure 4c ) \n as seen before ( dixon et al . , 2015 ) , genes in domains with a high domain score showed higher expression than genes in domains with a lower score ( figure s4a ) . \n a high domain score therefore does not reflect compaction , but rather compartmentalization of the domain . in agreement , lamina - associated domains ( lads ) , which have been linked with compacted chromatin ( peric - hupkes et al . , 2010 ) , \n overlapped mostly with tads that had a low domain score ( figure s4b ) . comparing \n the domain score between the different hi - c maps revealed a strong correlation between biological replicates , but not between different somatic cell types ( figure 4d ) . \n tissue - specific genes often resided in tads with an above average , cell - type - specific , domain score ( figure s4c ) . \n reprogramming of the four cell types resulted in highly correlated domain scores across all ipscs and similar to the scores measured in escs ( figure 4d ) . \n thus , also at the intra - tad level reprogramming was accompanied by large - scale topological changes , resulting in domains that overall are fairly uniformly organized between all ipsc lines . \n although our datasets are relatively sparse compared with published multibillion read datasets ( rao et al . , 2014 ) , we could clearly see chromatin loops at multiple sites in the genome ( exemplified for two genes in figure 5a ) . to identify chromatin loops in a systematic manner \n , we developed an algorithm that deals with relatively sparse data ( see supplemental experimental procedures ) . \n we combined all the p3 ipsc line data into a dataset that contained over 220 million unique contacts . \n based on these data , we identified 5,168 chromatin loops , 97% of which were found within a tad ( table s4 ) . \n the median loop size was 249 kb ; 5% spanned less than 99 kb , and 5% spanned more than 590 kb . intersecting these loops with ctcf binding sites observed by chip - seq in the ipscs ( see below ) revealed that 67% of the chromatin loops were formed between pairs of ctcf sites . consistent with previous reports ( rao et al . , 2014 ) , the participating ctcf sites were found overwhelmingly oriented in a convergent manner ( figure s5a ) . \n analysis of the hi - c datasets of the founder tissues revealed 2,741 , 2,666 , 846 , 536 loops for pre - b cells , nscs , mefs , and m , respectively ( table s4 ) , which is in line with the number of informative read pairs sequenced per library . to study the structural dynamics during reprogramming at the level of chromatin loops \n , we developed a hi - c meta - loop analysis ( figure s5b ) . in this analysis , we aligned one of our hi - c datasets on the loop calling data from another hi - c dataset , scaled the data between the beginning and end of each loop , and projected all contact maps on top of each other . \n the resulting plots visualize whether loops scored in one tissue are overall conserved in other tissues . \n when we performed a meta - loop analysis of the p3 ips loops in e14 esc hi - c data , we found a strong enrichment of contacts at the site of the loops ( figure 5b ) , showing that most loops called in ipscs were conserved in escs . \n when we intersected the same ips loops with hi - c data from the founder tissues , we also found enrichment of contacts at the site of the loops ( shown for pre - b cells in figure 5b ) . \n we then defined founder - specific loops as those being present in a given cell type but absent in all other somatic cell types \n . we could identify tissue - specific loops in pre - b , nsc , and ipscs ( 346 , 27 , and 246 , respectively ) . \n genes associated with pre - b cell - specific loops were expressed significantly higher in pre - b cells than in the other cells ( p < 0.0001 , for all comparisons , wilcoxon rank sum test ; figures 5c and s5c ) , supporting the idea that lineage - restricted chromatin loops contribute to tissue - specific transcriptional activity ( rao et al . , 2014 ) . \n we next asked whether such somatic cell - type - specific loops are retained in the corresponding ipscs . \n figure 5d shows that in general this was not the case . when we took the pre - b cell - specific chromatin loops , the meta - loop plot of pre - b cell derived ipscs no longer showed preferential contacts between the loop anchors : in fact , the plot looked identical to that of another ips line or of nscs ( figure 5d ) . in all tissues , however , the intervening sequences appeared to form contact domains even in the absence of an encompassing chromatin loop . \n the expression bias seen in somatic cells ( figure 5c ) disappeared with the loss of tissue - specific loops during reprogramming . \n thus , the genes involved in pre - b - cell - specific chromatin loops , which are more highly expressed in pre - b cells than in other somatic cells , showed no residual increased expression in pre - b - derived ipscs as compared with other ipscs ( figure s5d ) . \n in addition , when inspecting individual gene loci , we could clearly see the disappearance of tissue - specific chromatin loops . for example , ikaros , ctgf , anks1b , and f7 loci all contained strong chromatin loops in pre - b , mef , nsc , and m , respectively , of which most disappeared during reprogramming ( figure 5e ) . \n while the hi - c metaloop analysis showed that the majority of founder - specific chromatin loops dissolve during reprogramming , it still remained possible that rare but possibly important tissue - specific loops are transmitted to their ipsc derivatives . to investigate this in more detail , we visually inspected the 346 pre - b - specific loops in the hi - c datasets of pre - b cells and its reprogrammed derivatives . also , upon visual inspection , the great majority ( 326 ) of these loops was found to dissolve upon reprogramming ( for example , see figure 5e ) . \n twenty pre - b cell loops also showed an ( often weak ) looping signal in the pre - b derived p3 ipscs , but 17 of these also had a looping signal in one or more of the unrelated ipscs ( for examples , see figure s5e ) . \n the three pre - b - cell - specific loops that were transmitted to and exclusively detectable in pre - b - derived ipscs located near mcl1 , ccdc69 , and amph genes not known to be important for b cell identity . \n we therefore find no evidence for looping memory and conclude that tissue - specific chromatin loops near cell identity genes effectively dissolve during reprogramming . \n intersections with other hi - c data showed that these loops were also present in escs but absent in all founder hi - c datasets ( figure 5f ) . \n this confirmed that they were formed de novo during reprogramming and were specific for pluripotent cells . \n when we checked the individual loci involved , we noticed that they often contained pluripotency genes , including sox2 , prdm14 , nanog , fgf4 , and sox1 ( figure 5 g ) . \n thus , while many chromatin loops , particularly those between domain boundaries , were conserved between escs , ipscs and somatic cells types , there were also tissue - specific chromatin loops that contributed to cell - specific expression programs . during reprogramming , \n most somatic cell - specific loops were lost while new specific regulatory contacts , often involving pluripotency genes , were established . \n we considered the possibility that not all important pluripotent loops are properly established during reprogramming . \n our hi - c datasets were of insufficient resolution to conclusively analyze this , but to get an impression , we focused on 207 loci previously established to contain super - enhancers in escs ( whyte et al . , \n . we could appreciate chromatin loops at 84 of these loci in escs , 37 of which were not appreciable in our pre - b hi - c dataset . \n all but two of these loops were also detectable in the ipsc hi - c data ( for examples , see figures s5f and s5 g ) . \n the exceptions included the genes tsc22d1 and , interestingly , sall4 , a known key pluripotency gene , where es - specific loops were less appreciable in ipscs . \n sall4 expression was nevertheless induced in all ipscs ( figure 2a ) , making it difficult to judge the functional significance of these differential dna contacts . \n we conclude that reprogramming is accompanied by efficient loop formation at nearly all analyzed key pluripotent regulatory sequences , demonstrating that it robustly reshapes the chromatin not only at the tad but also at the sub - tad level to adopt a pluripotent conformation . to further search for a possible topological memory during reprogramming , we asked whether structural domains exist which keep a tissue - restricted positioning in either the a or b compartment during reprogramming . \n as shown before , nearly all domains adopted the same nuclear environment in p3 passage ipscs irrespective of their cell of origin ( figure 3 ) . \n only three domains in pre - b cells and none in the other founder lines were found to maintain a cell - of - origin - specific location during reprogramming . \n the fact that only in pre - b cells a few domains memorized their founder - specific location during reprogramming suggests that topological memory during reprogramming , if it exists , is not detectable at this level of genome organization . \n we then looked at the domain score ; as explained before , this gives a measure for intra - tad connectivity . \n unsupervised hierarchical clustering based on the domain score revealed that , with three exceptions , all p3 ipsc lines clustered based on their cell of origin ( figure 6a ) . \n intriguingly , the three exceptions ( one m , one mef , and one nsc - derived ipsc line ) were the only three lines showing aneuploidy , carrying an extra copy of a chromosome ( figure s6a ) . \n such genomic instability during reprogramming has been reported before ( weissbein et al . , 2014 ) . \n to identify the domains with a cell - of - origin - specific topology , we carried out k - means clustering on domain scores from p3 ipscs lines with a normal karyotype . \n figure 6b shows clusters of domains grouped according to conserved differences in domain score across the four types of p3 ipscs . \n unexpectedly , the same domain clusters in the founders showed uncorrelated scores within and between tissues , indicating that the cell - of - origin - dependent domain structures are not reflective of residual founder - specific structures and therefore not a consequence of 3d memory . to further understand , this we again performed k - means clustering but now based on the domain scores measured in the founder lines ( figure 6c ) . \n seven distinct clusters of domains with unique founder - dependent structures could be delineated , but their tissue - restricted architectural features were not appreciable in either p3 or p20 ipscs and were therefore efficiently erased during reprogramming . \n indeed , there was no significant overlap between the founder and p3 ipsc defining domains ( p = 0.3 , hypergeometric test ) . \n collectively , this shows that the 3d genome of ipscs carries features that allow linking the cells to their cell of origin . \n these topological features , however , are not remnants of founder - specific 3d structures and therefore do not reflect memory . rather , we propose that these distinguishing topological domain features are acquired during reprogramming in a reproducible and cell - of - origin - dependent manner . to explore the origin of founder - dependent domain structures , we first investigated whether they are associated with distinct expression patterns in p3 ipscs . for this , we intersected the clusters of structural domains with the clusters of genes that showed cell - of - origin - dependent expression patterns in p3 ipscs . \n no correlation was observed ( data not shown ) , not even when considering all expressed genes in these domains and asking whether the domains showed any distinguishable transcriptional output in p3 ipscs ( figure 6d ) . \n thus , there seems no ( causal ) relationship between domains having a cell - of - origin - specific topology in p3 ipscs and the expression of genes contained within these domains . \n one could speculate that the erasure of founder - specific transcription programs is accompanied by tissue - restricted deposition of epigenetic marks at the corresponding genes , which , if maintained during reprogramming , causes cell - of - origin - specific structural features in p3 ipscs . to investigate this , we performed an identical analysis as above , but now intersecting the hi - c data from p3 ipscs with founder - specific transcriptome data . \n two ipsc clusters with cell - of - origin - specific domain scores were significantly enriched for genes with a founder - specific expression signature . also , for some clusters , the overall transcriptional output differed specifically in the corresponding founder cells ( figure 6d ) . \n finally , we asked whether ctcf , a key chromatin architectural protein , could be involved in the establishment of specific structural features during reprogramming . for this , we performed ctcf chip - seq experiments , using a total of eight p3 and eight p20 ipsc lines , i.e. , in duplicate for all founder tissues ( figure s6b ) . already at p3 \n reproducible , cell - of - origin - dependent differential ctcf binding sites were also observed , but these were relatively rare ( 327 for pre - b , 136 for nsc , 143 for m , and 116 for mef ipscs ) and showed low chip - seq scores ( figure s6c ) . most of the differential cell - of - origin ctcf binding sites in p3 ipscs were still conserved in the corresponding p20 ipscs ( figure 6f ) . \n however , they were not detectable as ctcf bound sites in the corresponding founder cells , as judged from published chip - seq data . \n thus , as also concluded for founder - associated expression patterns and domain structures , the founder - associated ctcf binding events observed in p3 ipscs seem to have been acquired during reprogramming , rather than representing memory . \n moreover , they were not enriched in any of the p3 passage structural domain clusters , implying that the cell - of - origin - specific 3d genome features are not related to rare and weak differential , cell - of - origin - associated , ctcf - binding events . \n our results demonstrate that somatic cell genomes have highly distinct 3d structures that after cell reprogramming into ipscs converge into an esc - like topology . \n we find that reprogramming induces ( 1 ) large - scale switching of tads between the a and b compartments , ( 2 ) the disassembly of inter - tad contacts mediated by founder - specific transcription factors and the construction of new contacts mediated by pluripotency factors , and ( 3 ) the disruption of founder - specific chromatin loops and de novo establishment of pluripotent chromatin loops . \n interestingly , despite these massive structural reorganizations that reproducibly induce nearly identical , esc - like , 3d genomes across all different ips cell lines , p3 passage ipscs derived from different somatic cell types can still be distinguished based on specific genome topology features ( figure 7 ) . \n the cells can also be distinguished based on their expression signatures ( figure 2f ) , as reported before ( polo et al . , 2010 ) . \n in addition to the cell - of - origin - specific topological features and expression patterns in ipscs , we observe founder cell - associated ctcf - binding events . \n however , differing from previous studies , our systematic analyses suggest that in general the cell - of - origin - specific expression patterns in ipsc lines do not reflect residual expression patterns inherited from the respective founders . \n similarly , the cell - of - origin - specific topological features that we observe in ipscs are not architectural features of the founder genomes that survived topological reorganization during reprogramming . \n the same is true for the cell - of - origin - dependent ctcf binding events that we observe in ipscs ; we find no evidence that they were already occupied by ctcf in the somatic founder cells . \n instead , in all instances , these patterns seem to be acquired during reprogramming in a reproducible and cell - of - origin - specific manner . \n the finding that expression of most cell - type - specific genes can no longer be detected in ipscs may reflect the fact that efficient erasure of somatic - cell - specific transcription programs is a prerequisite for the establishment of a pluripotent cell population ( buganim et al . , 2013 ) . \n similarly , our data suggest that ipscs can only tolerate architectural fluctuations and changes in ctcf binding events that do not challenge , via their impact on gene expression , the establishment , and maintenance of the pluripotent state . as such , we propose they represent innocuous side effects of reprogramming . the observation that ipscs derived from different somatic cell types \n have distinct transcriptional and genome topology features seems best explained by assuming that different somatic cell types follow distinct reprogramming trajectories . \n consistent with this idea , single - cell expression analyses during reprogramming of mefs into ipscs identified the transient expression of a unique set of surface markers absent in both fibroblasts and ips cells , revealing transitions through distinct intermediate stages ( lujan et al . , 2015 , omalley et al . , 2013 ) . \n furthermore , mefs may follow different paths , depending on the reprogramming method used ( zunder et al . , 2015 ) . \n while little is known about the reprogramming paths in cell types other than fibroblasts , the reactivation sequence of pluripotency genes during reprogramming has been shown to differ between mefs and pre - b cells ( buganim et al . , 2012 , di stefano et al . , 2014 , omalley et al . , 2013 ) , supporting the idea that different cell types may exhibit distinct reprogramming trajectories . \n future research is necessary to uncover the molecular basis of the correlation between the distinct reprogramming trajectories , tissue - specific gene expression signatures , and genome topologies in the different cell - of - origin - derived ipscs . \n it has been reported that low passage ipscs harbor residual dna methylation signatures characteristic of their somatic tissue of origin , and these have been suggested to explain the cells biases in differentiation potential ( kim et al . \n , 2010 ) . whether differential methylation is also linked to the distinct topological features that we have observed in p3 ipscs remains to be investigated . \n however , given the effective replacement of a founder - specific 3d genome by a pluripotent 3d genome during reprogramming , plus the fact that the distinctive structural features are subtle and not reflective of architectural hallmarks of the founder genome , we consider it unlikely that the cell - of - origin - specific differentiation bias seen in early ipscs is a consequence of specific topological features . \n additional information and details regarding this work may be found in the supplemental experimental procedures . \n pre - b cells , mefs , m , and nscs were isolated from a reprogrammable mouse line containing a doxycycline - inducible oskm cassette , the reverse tetracycline transactivator ( rtta ) ( carey et al . , 2010 ) , and an oct4-gfp reporter transgene ( boiani et al . , 2002 ) , as described ( di stefano et al . , 2014 ) . reprogramming experiments with pre - b cells were performed as previously described ( di stefano et al . , 2014 ) ; with mefs , macrophages and nscs were conducted by plating 100,000 cells per well on gelatinized plates seeded with irradiated mefs , using esc medium supplemented with 2 g / ml of doxycycline . for the isolation of ipsc lines , \n doxycycline was washed out after 15 days of reprogramming , and colonies with esc - like morphology were picked at 20 days before further passaging . \n ipsc lines were expanded for an additional 9 days ( three passages ) to obtain p3 ips cell lines or for 20 passages to obtain p20 ips cell lines . \n detailed information on cell culture and characterization of the ipscs is provided in the supplemental experimental procedures . \n chip experiments were performed as described previously ( van oevelen et al . , 2008 ) using an antibody against h3k27ac ( ab4729 , abcam ) and ctcf ( millipore , 07 - 729 ) . \n pre - b cells , mefs , nscs , ipscs , and e14 escs were cross - linked and further processed as dpnii 3c template , as previously described ( splinter et al . , 2012 ) . \n libraries for paired - end sequencing were generated from sonicated , 500- to 800-bp size - selected , 3c templates using the truseq dna lt sample prep kit ( illumina ) . \n detailed information on hi - c template generation and hi - c data analysis is provided in the supplemental experimental procedures . \n hi - c eigenvalues , domain segmentation in ipsc p3 , and a list with genomic coordinates of all the called chromatin loops can be found in the tables s2 , s3 , and s4 , respectively . \n ", "role": "user" }, { "content": "summaryforced expression of reprogramming factors can convert somatic cells into induced pluripotent stem cells ( ipscs ) . \n here we studied genome topology dynamics during reprogramming of different somatic cell types with highly distinct genome conformations . \n we find large - scale topologically associated domain ( tad ) repositioning and alterations of tissue - restricted genomic neighborhoods and chromatin loops , effectively erasing the somatic - cell - specific genome structures while establishing an embryonic stem - cell - like 3d genome . yet , early passage ipscs carry topological hallmarks that enable recognition of their cell of origin . \n these hallmarks are not remnants of somatic chromosome topologies . instead , \n the distinguishing topological features are acquired during reprogramming , as we also find for cell - of - origin - dependent gene expression patterns .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: all animal studies were performed in accordance with guidelines of the institutional animal care and use committee at harvard medical school . the tet1-ko mouse strain ( b6;129s4-tet1/j ) was purchased from jackson laboratory . \n all male mice were mated with c57bl/6j female and the mating is timed in the way that appearance of vaginal plug at noon is defined as embryonic day ( e ) 0.5 . \n e19.5 embryos and placentae were harvested by dissecting pregnant females with progesterone injection at e17.5 and e18.5 . \n all data presented were generated by using three or four separate mating pairs as biological replicates . \n embryos and placentae in the uterus were fixed in 4% paraformaldehyde , dehydrated in ethanol , and embedded in paraffin . for histological analysis , sections ( 5 m ) \n total rnas were isolated with trizol ( life technologies ) , and cdnas were generated with random primer sets and superscript iii first - strand synthesis system ( invitrogen ) . \n real - time qpcr reactions were performed on an abi viia7 sequence detection system ( applied biosystems ) using sybr green ( applied biosystems ) . \n relative gene expression levels were calculated using comparative ct values , in which ct is the cycle threshold number , and normalized to gapdh . \n briefly , the transgenic mouse line containing the gof18dpe - egfp [ tg(pou5f1-egfp ) ] transgene was purchased from jackson laboratory . \n after washing with phosphate buffer medium ( pb1)/bsa solution , tissues were incubated in hyaluronidase , washed and then re - suspend in pbs . \n germ cells were purified based on the expression of gfp using facs aria ii flow cytometry ( bd bioscience ) , and stored in 80c until use . \n two biological replicates for tet1-ko and wild type pgcs were combined and split into two as the technical replicates . \n total rna was purified with an rneasy mini kit ( qiagen ) , in which an on - column dnase treatment was included . \n 500 ng of purified rna was then subjected to mrna isolation and library preparation using a nebnext ultra rna directional library prep kit for illumina with the poly ( a ) mrna magnetic isolation module ( neb ) following manufacturer 's instructions . \n libraries were pooled and sequenced on an illumina hiseq 2500 ( single - end , 50bp ) . \n rna - seq data analysis was performed with tophat and cufflinks using the ucsc mm9 annotation . \n bs - seq was performed using the ez dna methylation gold kit ( zymo research ) following the manufacturer 's instruction . \n for rrbs , the libraries were generated essentially as previously described , with some modifications . \n briefly , dna was digested with mspi ( neb ) , and then subjected to end repair , and ligation of methylated custom adaptors ( forward : 5-acactctttccctacacgacgctcttccgatc*t-3 , reverse : 5-/5phos / gatcggaagagcacacgtctgaactccagtc-3 , where * indicates phosphorothioate bond ) with a nebnext ultra dna library prep kit for illumina ( neb ) . \n size selection was conducted by purifying the adaptor - ligated dna twice with 1.5 spriselect beads ( beckman coulter ) . \n size selected libraries were treated with sodium bisulfite using the epitect fast bisulfite conversion kit ( qiagen ) . \n after clean - up , the optimal , minimum pcr cycle numbers required to generate the final libraries were determined by qpcr using kapa 2 g robust hotstart readymix ( kapa ) with 0.3 sybr i. final libraries were generated by scaled - up pcr reactions ( without sybr i ) using the cycles determined above with barcoded primers from nebnext multiplex oligos kit ( neb ) , and purified with 1.2 spriselect beads . \n libraries were pooled and sequenced on an illumina hiseq 2500 ( single - end , 50bp ) . \n adapter trimming for raw reads from each sample was performed using trim galore ( babraham bioinformatics ) , and the data quality was examined using fastqc ( babraham bioinformatics ) . \n the trimmed reads were mapped against the mouse genome ( mm9 build ) with bismark v0.7.12 , and the methylation call for every single c was extracted by bismark methylation extractor script . \n we only keep the cpgs that were covered by at least 8 reads ( common 8x cpgs ) . \n . for 100 bp tiles and the promoters , reads for the cpgs that were covered at least 8x in each sample were pooled and used to estimate the methylation level by taking the number of reads reporting a c , divided by the total number of reads reporting a c or t. we keep the 100 bp sites and the promoters with at least 2 and 4 common 8 cpgs for subsequent analyses . \n more than 10% methylation level changes were required to be classified as changed sites or promoters . \n based on the assumption that no hypomethylated sites in tet1-ko pgcs should appear , estimated empirical false discovery rate ( fdr ) by the number of hypomethylated sites in tet1-ko pgcs was 0.054 . \n annotation of cpg islands was obtained from a previous report based on pull down experiments . \n promoters were defined as the region 1.5 kb to + 1.5 kb of the transcription start site as annotated in refseq genes . \n repeat annotations were extracted from the ucsc table browser repeatmasker track ( mm9 build ) . \n dmrs were functional characterized by great using the mouse genome informatics ( mgi ) phenotype ontology . \n publically available datasets for whole genome bisulfite sequencing ( wgbs ) data sets in pgcs were included in this analysis where indicated . for wgbs data analyses , \n all the informative cpgs were used , and the methylation level in a region were estimated by taking the number of reads reporting a c , divided by the total number of reads reporting a c or t. we required that there are at least 20 methylated or unmethylated cytosine observations in the region for each sample . \n all animal studies were performed in accordance with guidelines of the institutional animal care and use committee at harvard medical school . the tet1-ko mouse strain ( b6;129s4-tet1/j ) was purchased from jackson laboratory . \n all male mice were mated with c57bl/6j female and the mating is timed in the way that appearance of vaginal plug at noon is defined as embryonic day ( e ) 0.5 . \n e19.5 embryos and placentae were harvested by dissecting pregnant females with progesterone injection at e17.5 and e18.5 . \n all data presented were generated by using three or four separate mating pairs as biological replicates . \n embryos and placentae in the uterus were fixed in 4% paraformaldehyde , dehydrated in ethanol , and embedded in paraffin . for histological analysis , sections ( 5 m ) \n total rnas were isolated with trizol ( life technologies ) , and cdnas were generated with random primer sets and superscript iii first - strand synthesis system ( invitrogen ) . \n real - time qpcr reactions were performed on an abi viia7 sequence detection system ( applied biosystems ) using sybr green ( applied biosystems ) . \n relative gene expression levels were calculated using comparative ct values , in which ct is the cycle threshold number , and normalized to gapdh . \n briefly , the transgenic mouse line containing the gof18dpe - egfp [ tg(pou5f1-egfp ) ] transgene was purchased from jackson laboratory . \n e13.5 genital ridge cells were dissociated with 0.05% trypsin / edta treatment with pipetting . after washing with phosphate buffer medium ( pb1)/bsa solution , \n germ cells were purified based on the expression of gfp using facs aria ii flow cytometry ( bd bioscience ) , and stored in 80c until use . \n two biological replicates for tet1-ko and wild type pgcs were combined and split into two as the technical replicates . \n total rna was purified with an rneasy mini kit ( qiagen ) , in which an on - column dnase treatment was included . \n 500 ng of purified rna was then subjected to mrna isolation and library preparation using a nebnext ultra rna directional library prep kit for illumina with the poly ( a ) mrna magnetic isolation module ( neb ) following manufacturer 's instructions . \n libraries were pooled and sequenced on an illumina hiseq 2500 ( single - end , 50bp ) . \n rna - seq data analysis was performed with tophat and cufflinks using the ucsc mm9 annotation . \n bs - seq was performed using the ez dna methylation gold kit ( zymo research ) following the manufacturer 's instruction . \n primers for bs - seq are listed in supplementary table 9 \n . for rrbs , \n briefly , dna was digested with mspi ( neb ) , and then subjected to end repair , and ligation of methylated custom adaptors ( forward : 5-acactctttccctacacgacgctcttccgatc*t-3 , reverse : 5-/5phos / gatcggaagagcacacgtctgaactccagtc-3 , where * indicates phosphorothioate bond ) with a nebnext ultra dna library prep kit for illumina ( neb ) . \n size selection was conducted by purifying the adaptor - ligated dna twice with 1.5 spriselect beads ( beckman coulter ) . \n size selected libraries were treated with sodium bisulfite using the epitect fast bisulfite conversion kit ( qiagen ) . \n after clean - up , the optimal , minimum pcr cycle numbers required to generate the final libraries were determined by qpcr using kapa 2 g robust hotstart readymix ( kapa ) with 0.3 sybr i. final libraries were generated by scaled - up pcr reactions ( without sybr i ) using the cycles determined above with barcoded primers from nebnext multiplex oligos kit ( neb ) , and purified with 1.2 spriselect beads . \n libraries were pooled and sequenced on an illumina hiseq 2500 ( single - end , 50bp ) . \n adapter trimming for raw reads from each sample was performed using trim galore ( babraham bioinformatics ) , and the data quality was examined using fastqc ( babraham bioinformatics ) . \n the trimmed reads were mapped against the mouse genome ( mm9 build ) with bismark v0.7.12 , and the methylation call for every single c was extracted by bismark methylation extractor script . \n we only keep the cpgs that were covered by at least 8 reads ( common 8x cpgs ) . \n the methylation pattern was visualized by integrative genomics viewer ( igv ) . for 100 bp tiles and the promoters , reads for the cpgs that were covered at least 8x in each sample were pooled and used to estimate the methylation level by taking the number of reads reporting a c , divided by the total number of reads reporting a c or t. we keep the 100 bp sites and the promoters with at least 2 and 4 common 8 cpgs for subsequent analyses . \n more than 10% methylation level changes were required to be classified as changed sites or promoters . based on the assumption that no hypomethylated sites in tet1-ko pgcs should appear , estimated empirical false discovery rate ( fdr ) by \n annotation of cpg islands was obtained from a previous report based on pull down experiments . \n promoters were defined as the region 1.5 kb to + 1.5 kb of the transcription start site as annotated in refseq genes . \n repeat annotations were extracted from the ucsc table browser repeatmasker track ( mm9 build ) . \n dmrs were functional characterized by great using the mouse genome informatics ( mgi ) phenotype ontology . \n publically available datasets for whole genome bisulfite sequencing ( wgbs ) data sets in pgcs were included in this analysis where indicated . for wgbs data analyses , \n all the informative cpgs were used , and the methylation level in a region were estimated by taking the number of reads reporting a c , divided by the total number of reads reporting a c or t. we required that there are at least 20 methylated or unmethylated cytosine observations in the region for each sample . \n ", "role": "user" }, { "content": "genomic imprinting is an allele - specific gene expression system important for mammalian development and function 1 . the molecular basis of genomic imprinting is allele - specific dna methylation 1,2 . \n while it is well known that the de novo dna methyltransferases dnmt3a / b are responsible for the establishment of genomic imprinting 3 , how the methylation mark is erased during primordial germ cell ( pgc ) reprogramming remains a mystery . \n tet1 is one of the ten - eleven translocation family proteins , which have the capacity to oxidize 5-methylcytosine ( 5mc ) 4 - 6 , specifically expressed in reprogramming pgcs 7 . \n here we report that tet1 plays a critical role in the erasure of genomic imprinting . \n we show that despite their identical genotype , progenies derived from mating between tet1-ko males and wild - type females exhibit a number of variable phenotypes including placental , fetal and postnatal growth defects , and early embryonic lethality . these defects are , at least in part , caused by the dysregulation of imprinted genes , such as peg10 and peg3 , which exhibit aberrant hypermethylation in the paternal allele of differential methylated regions ( dmrs ) . \n rna - seq reveals extensive dysregulation of imprinted genes in the next generation due to paternal loss function of tet1 . \n genome - wide dna methylation analysis of e13.5 pgcs and sperms of tet1-ko mice revealed hypermethylation of dmrs of imprinted genes in sperm , which can be traced back to pgcs . \n analysis of the dna methylation dynamics in reprogramming pgcs suggests that tet1 functions to wipe out remaining methylation , including imprinted genes , at the late reprogramming stage . \n we further provide evidence supporting tet1 's role in the erasure of paternal imprints in female germline . \n thus , our study establishes a critical function of tet1 in genomic imprinting erasure .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: mri of the breast has been applied clinically for more than 20 years , and in western countries methods of using , it has been established in the form of guidelines [ 1 , 2 ] . \n the core applications of mri of the breast lie in detecting , diagnosing , and evaluating the efficacy of treatment of breast cancer [ 1 , 2 ] . today , however , besides the information on tumor morphology and blood flow obtained by contrast - enhanced mri , it has become possible to obtain a variety of function images and molecular information , and pet and mr spectroscopies are representative studies that are capable of actually being used clinically . \n choline is considered an important metabolite in proton mr spectroscopy in the mammary gland area . \n cholines are substances that have attracted interest in regard to every organ and disease , and because they are precursors of the phospholipids that compose cell membranes , increases in choline signals are thought to reflect increased membrane synthesis . in the mammary gland area \n , choline shows a promise of enabling differentiation between benign and malignant tumors and of serving as an indicator of tumor activity and viability . \n clinically , the attention has been focused on differentiation between benign and malignant tumors and prediction of the efficacy of chemotherapy . \n the markers that are useful in breast diseases are centered at 3.2 ppm and are generally referred to as the choline peak . \n however , myo - inositol , taurine , and so forth are included in the choline peak in addition to such compounds as choline ( cho ) , phosphocholine ( pc ) , and glycerophosphocholine ( gpc ) , which are parts of the membrane lipid metabolic pathways , and because of the closeness of the ranges of their chemical shifts , they are observed as a single peak when measurements are made in vivo . at the cellular level , gpc is higher than pc in normal breast tissue , and since a marked increase in pc and decrease in gpc have been demonstrated as a result of carcinogenesis , the main component in breast cancer is pc . \n moreover , it has been reported that if we examine minute chemical shifts even with a 1.5 t mr unit , it is possible to separate and observe a 3.22 - 3.23 ppm ( pc ) peak and a 3.27 - 3.28 ppm peak ( gpc / taurine / myo - inositol ) , and that they are useful in differentiating between benign and malignant tumors . \n the lactose peak is characteristic of the lactation period , and choline has also been found to be detected at 3.2 ppm during that period . \n the choline observed in the lactating breast matches the choline ( 3.27 ppm ) observed in benign diseases [ 4 , 6 ] . \n in contrast to the central nervous system area , because of the presence of normal tissue , fat , and so forth , in the mammary glands , the magnetic fields in the voxels tend to be nonhomogeneous . \n thus , when analyzing the spectra of tumors , it is important to set the voxels so that tissue outside the tumor is excluded . \n however , because there is a tradeoff between voxel size and acquisition time , a certain voxel size is unavoidable in order to obtain a high signal - to - noise ratio ( snr ) . assuming the addition of mr spectroscopy before or after approximately 20 to 30 minutes contrast - enhanced mri \n , we think being able to perform mr spectroscopy in approximately 10 minutes would be ideal , and a minimum voxel size of about 15 mm 15 mm 15 mm would therefore appear to be appropriate for lesions with a diameter of 1 cm or greater . \n in contrast to the central nervous system , manual shimming as well as autoshimming is essential to make the magnetic fields of the voxels homogeneous . with manual shimming , \n we use full width at half - maximum ( fwhm ) or t2 * for reference , and 2030 hz is the approximate target for fwhm . \n when the tumor is large , chemical shift imaging ( csi ) is sometimes even used as a means of assessing the internal nonhomogeneity of the tumor ( figure 1 ) . however , because multivoxelization is performed by using the point spread function by phase encoding , the same as for mri , contamination from adjacent voxels occurs . because of this defect , single - voxel spectroscopy is now the standard method . \n a spin - echo type , point - resolved spectroscopy sequence ( press ) is generally used in order to obtain single - voxel spectroscopy data . when selecting echo time ( te ) of proton mr spectroscopy , the decision as to whether to use a short te or long te involves making a tradeoff between signal intensity and signal contrast . \n a high snr is obtained with short te whereas long te is superior in terms of ability to separate the contrast signal from the fat signal . with long \n te ( 135270 ms ) , the signal intensity decreases , but the fact that the fat signal also decreases means an improvement in ability to detect the choline signal . \n application of mr spectroscopy to the whole body has recently increased greatly , and many methods of fat suppression have been developed . \n band - selective inversion with gradient dephasing ( basing ) is one of the latest fat suppression techniques and makes it possible to suppress any chemical shift spectrum signal desired by incorporating an additional pulse into the press sequence . \n the pulses used for suppression , such as chemical - shift selective ( chess ) excitation pulses , are positioned in the form of prepulses immediately before the excitation pulses whereas with basing the pulses for suppression are positioned within the body of the sequence itself . \n basing enables suppression of the peak of any chemical shift desired , and it has been applied to peak editing , and so forth . \n it is preferable for the water peak to persist to some extent in order to be able to use it as a standard to compute the chemical shift of a metabolite . \n while it is possible to perform water and fat suppression simultaneously by basing , we use chess for water suppression at our hospital because of its strong suppressive effect . \n it is possible to set the intensity of the residual water peak by setting the waiting time after applying the chess pulse . \n we actually set the waiting time after applying the chess pulse at 200 ms . \n two methods are available for quantification when performed by comparison with known concentrations : the internal reference method and the external reference method . in the internal reference method , \n the water signals in measurement voxels are used to quantify the target metabolites , whereas in the external reference method , a phantom is set up close to the measurement site , and the concentration in the volume in the phantom is used as the standard . \n we use the external reference method to perform quantification at our hospital . with the internal reference method , the water content of the voxels changes during chemotherapy , and that is a potential pitfall with using it . \n the greatest disadvantage of the external reference method is the need to perform an additional independent measurement as an external reference , and it also requires correction for the partial volume effect and separate calibration experiments . furthermore , since the t1 and t2 values of choline used were the values cited , there is the possibility of errors being introduced between these values and the actual values in the patients . \n in addition , because of patient movements , accurate correction is difficult even with frequency correction . \n however , quantification is essential in order to compare changes in the amount of choline for the patients treated with neoadjuvant chemotherapy . \n we believe that quantification is very useful and requires dedicated multidisciplinary team including radiologists , medical physicists , physicists , and chemists . at our hospital , we perform proton mr spectroscopy with a 1.5 t unit ( magnetom avanto ; siemens ag healthcare sector , erlangen , germany ) and circularly polarized ( cp ) and four - channel phased - array breast coil ( breast matrix coil ; siemens ag healthcare sector , erlangen , germany ) . \n the parameters used for mr spectroscopy are tr / te = 1620/270 ; voxel size = 15 15 15 mm ; acquisitions = 256 ; spectral width = 1,000 hz ; data points = 1,024 ; and the time of acquisition is 7 minutes . \n a cylindrical bottle phantom ( syngo grace external phantom ; siemens ag healthcare sector , erlangen , germany ) 4.0 cm high and 2.5 cm in diameter was inserted behind the breast coil and fixed in position . the phantom was filled with 1.25 g of niso46h2o per 1000 g of h2o . \n proton mr spectroscopy of the phantom was performed immediately after the mr spectroscopy examination of the breast lesion . \n the voxel size was 7 7 15 mm , and the acquisition time was 4 seconds . \n the following formula was used to calculate the scaling factor : \n\t\t\t\t\t\t\t\t ( 1)scaling factor = ( 106mwh2o)(nh2oncho ) (ft1h2oft1cho ) (ft2h2oft2cho)(voxelh2ovoxelcho)(coilsensh2ocoilsenscho),ft1=1exp ( trt1 ) , ft2=exp ( tet2 ) , \n\t\t\t\t\t\t\t where ncho and nh2o are the numbers of h nuclei of choline molecules and water molecules , respectively . the scaling factor can be converted to molar concentration by correcting for the number of h nuclei per molecule and the molecular weight of the solvent ( mwh2o ) . \n the ft1 and ft2 relaxation factors were corrected by using the equation for relaxation times . \n t1 was calculated from the images obtained with two different trs according to the spin - echo sequence , with te maintained constant , and t2 was calculated from the images obtained with 16 different tes with tr maintained constant . \n the mean t1 was 375 ms , and the mean t2 was 270 ms . \n ( t1cho = 1513 ms , t2cho = 269 ms ) were adopted as the t1 and t2 values for choline in vivo . \n the coil sensitivities indicate the signal intensity of the external reference phantom and the signal intensity within the imaging area . \n the signal intensity within the imaging area was obtained on proton - weighted images ( te / tr , 15/5000 ) with a solution phantom introduced into the measurement breast coil that was the same as the external reference solution . \n the spectroscopic data processing protocol was saved and linked to the measurement protocol within the syngo software ( siemens ag healthcare sector , erlangen , germany ) to ensure that data processing was identical for each measurement . \n the spectra were processed by zero - filling the 1028 data points to 2048 data points by applying a gaussian apodization function of 1.5 hz before fast fourier transformation . \n we fitted the choline peak and water peak with a gaussian function that ranged from 3.18 to 3.32 ppm for choline and was 4.7 ppm for water . \n the peak line widths were restricted according to the following settings ; the cho peaks were recognized as cho when the fwhm was less than 10 hz ; when the fwhm was 10 hz or more , the peaks no longer fit . \n the residual water signal was used for reference ( 4.7 ppm ) , and the frequency of any resonance detected in the 3.003.50 ppm spectral region was recorded . \n choline peaks at 3.213.23 ppm are assigned to phosphocholine ( pc ) and were evaluated by using a threshold snr of 2 [ 15 , 16 ] . \n when positive for choline , water subtraction and baseline correction with a sixth - order polynomial fit were applied to obtain the flat baseline of an mr spectrum . \n thus far , reports on clinical research on proton mr spectroscopy of the breast have centered on differentiating between benign and malignant lesions . \n however , the possibility of using 1.5 t to detect biomarkers of breast cancer has also been reported in recent years . \n below we comment on the possibilities related to the diagnostic power of proton mr spectroscopy for breast lesions . \n the major papers on the diagnostic performance of proton mr spectroscopy as a means of differentiating between benign and malignant tumors that were published between 1998 and 2009 are listed in table 1 [ 5 , 1523 ] . according to the data in the nine other papers after excluding our own , sensitivity ranged from 70% to 100% , and specificity ranged from 67% to 100% . \n sensitivity in the nine articles as a whole was 88% ( 165/187 ) , and specificity was 88% ( 126/144 ) , and the diagnostic performance reported was related to lesions of 1 cm or greater in size . \n the special characteristic of our own study is that we performed proton mr spectroscopy before biopsy in order to exclude any effects of bleeding or inflammation after a biopsy , and breast imaging recording and data system ( bi - rads- ) mri category 4 and 5 lesions were the subject of our study . \n there were 171 cases , more lesions than in any of the other studies , but a comparison with the previous studies showed that sensitivity was very low ( 44% ; 40/91 ) . \n we think the reasons for the low sensitivity were that the target lesions were small and that nonmass lesions were included . \n actually , when restricted to masses measuring 15 mm or more , sensitivity improved to 82% ( 28/34 ) . the first study of nonmass lesions by proton mr spectroscopy was reported by bartella et al . , and the results were favorable , that is , a sensitivity of 100% and a specificity of 85% . \n by contrast , the results for sensitivity in our own research were very low , 32% ( 9/28 ) , and specificity was 75% ( 12/16 ) ( table 2 ) . \n one of the reasons for this is thought to be differences between the types of cancers that were the subject of the studies . \n ductal carcinoma in situ ( dcis ) accounted for 17% ( 2/12 ) of the cancers in the report by bartella et al . \n the morphologic patterns of dcis were variable on mri and included a branching - ductal pattern and a scattered clumped pattern in cases with low tumor density at histology and confluent clustered rings in those with high tumor density at histology . \n therefore , the diagnostic performance for nonmass lesions of proton mr spectroscopy with the 1.5 t mr unit currently being used does not appear to be satisfactory , and we think it will be necessary to assess stronger magnetic fields in the future . \n it also appears that in the future , it will be necessary to improve the coils , optimize the measurement sequence , and increase the precision of the data postprocessing . \n however , false - negative cases have been reported even in relatively large invasive cancers , and in addition to invasive ductal carcinoma , they have been reported in medullary carcinoma [ 19 , 21 ] , mucinous carcinoma , and apocrine carcinoma . \n the existence of these false - negative cases corroborates the fact that biopsy must not be avoided on the basis of negative proton mr spectroscopy findings alone . \n fibroadenoma [ 5 , 15 , 16 , 19 , 22 , 23 ] , tubular adenoma [ 17 , 18 ] , intraductal papilloma , mastopathy ( including benign proliferative disease ) [ 5 , 18 , 22 , 23 ] , inflammatory lesions with atypia , and atypical ductal hyperplasia [ 16 , 22 ] have been reported . \n the elevated choline level in breast cancer may be associated with increased membrane synthesis by replicating cells , however , benign tissues , such as proliferative fibroadenoma , may also produce a positive - choline signal . \n when we measured the proton mr spectroscopy of the breast parenchyma in 920 cases at our hospital , however , we observed a choline peak in 12% ( 113/920 ) , and 32% of the choline peaks ( 36/113 ) were consistent with the choline that is seen in malignancy ( pc ; 3.213.23 ppm ) ( figure 2 ) . \n the exact reason for this phenomenon is unknown , but the increase in choline in the breast parenchyma may be greater than previously thought . \n this is important in terms of clinical diagnosis , and caution is required because of the possibility of intermingling by very weak choline in the surrounding area , especially when a voxel that is larger than the lesion is placed . since breast lesions are usually detected by mri after contrast medium has been injected , we tried performing proton mr spectroscopy after contrast - enhanced mri , and the gadolinium contrast medium appeared to have a very slight effect the mr spectrum of the lesion . \n used on a 3 t mr unit to conduct a study of the effect of six gadolinium contrast media ( magnevist , multihance , omniscan , optimark , prohance , and dotarem ) on mr spectroscopy performed on phantoms and a rat model of breast cancer . \n the results obtained with the phantom showed that the width of the choline peak broadened with three of the contrast media , that is , magnevist , multihance , and dotarem , and the volume of the peak decreased to an average of about 40% . the use of negatively - charged chelates may be associated with the underestimation of the choline level present in the lesion , and their conclusion was to recommend the use of neutral chelates for mr spectroscopy of the breast . \n we attempted to determine the effect on the choline spectrum at our hospital by using two different contrast media ( negatively - charged chelates and neutral chelates ) , magnevist ( gadopentetate dimeglumine , gd - dtpa ) and omniscan ( gadodiamide , gd - dtpa - bma ) . \n we used each of the two contrast media on a different day in 30 patients who had been found to have an enhanced mass , and we compared the changes in width and height of the choline peaks . \n the results did not show any statistically significant changes in the width or height of the choline peak due to the contrast media ( figure 3 ) , and no statistically significant differences in fwhm or t2 * during shimming were observed in the same cases . \n we think these findings suggested that the impact of the contrast medium in clinical settings in which 1.5 t mri is used is very mild . \n mr spectroscopy is more strongly impacted by the location of the tumor ( skin and vicinity of the chest wall ) and the imaging conditions , and the impact of the contrast medium appears to be trivial by comparison . \n the potential of proton mr spectroscopy as a means of biomarkers of breast cancer has already been investigated in many ex vivo studies . \n . reported being able to differentiate grade i and ii breast cancers from grade iii breast cancers based on mr spectroscopy findings in an ex vivo study of fine - needle aspiration specimens . \n we have reported similar findings in vivo , as described below . in our study , the choline levels measured by proton mr spectroscopy with a 1.5-t unit correlated well with the histological prognostic factors , that is , nuclear grade , estrogen receptor status , and triple - negative lesion status . \n it is hoped that in vivo research on proton mr spectroscopy to detect biomarkers will contribute to breast cancer therapy , including drug therapy . \n the role of diagnostic imaging in neoadjuvant chemotherapy lies in diagnosing the spread of residual tumors after chemotherapy and in judging the efficacy of the chemotherapy . \n there are two very important points in regard to the diagnosis of the spread of residual lesions after chemotherapy : the pattern of tumor spread before chemotherapy and the pattern of tumor shrinkage after chemotherapy , and when this information is taken into consideration , it appears possible to perform breast - conserving surgery safely . \n judging the efficacy of chemotherapy , on the other hand , means evaluating the chemosensitivity of the tumor in vivo . \n many reports have shown that the variety of information provided by mri ( tumor diameter , changes in volume , and changes in blood flow ) is more useful than the information provided by palpation or ultrasonography [ 3134 ] . a great deal of hope \n as stated above , since proton mr spectroscopy has a role in the evaluation of treatment of breast diseases by providing molecular information , it is regarded as an effective method for monitoring the activity of breast cancer and for early prediction of the efficacy of chemotherapy [ 3543 ] . \n accurate assessment of the response to neoadjuvant chemotherapy is one of the critical factors for optimizing the chemotherapy regimen and planning further surgery . \n the greatest advantages of early prediction of efficacy are being able to reduce unnecessary adverse effects , prevent treatment delays , and avoid unnecessary administration of expensive drugs that do not show promise of being effective . \n since methods that alter mr spectroscopy voxels according to the size of the tumor during the course of breast cancer chemotherapy are routine [ 36 , 40 ] , quantification is essential in order to compare changes in the amount of choline . \n however , the reproducibility of the quantitative values themselves is a problem , because when the voxels are altered , shimming accuracy and the snr change . \n we therefore gave priority to obtaining stabilized voxels that could be compared before and after treatment and tried a method in which we fix voxel size and position the voxel at the same site as the lesion . \n however , because this is not the standard method , we first investigated its accuracy by making comparisons with pet / ct in the same patients . \n the results of the comparisons of the amount of choline ( integral values ) obtained by mr spectroscopy and the standardized uptake value ( suv ) obtained by pet / ct showed that the changes in the two perfectly paralleled each other . \n when we fixed the voxel size , there appeared to be major advantages from a clinical standpoint in terms of being able to fix the scanning parameters , such as receiver gain , and easily observe increases in choline within the unit voxel . \n on the other hand , one of the disadvantages of this technique is that tumor metabolism can only be observed partially in tumors larger than the voxel size . \n the other is that the tissue surrounding the tumor is included in the voxel when the tumor becomes smaller than the voxel as a result of regression . \n however , if mr spectroscopy is used to identify nonresponders early , this disadvantage is avoidable . \n further studies are needed to examine the advantages and disadvantages of this technique in a larger number of patients . \n there have been more reports of using pet / ct for early prediction of the efficacy of chemotherapy for breast cancer than of using proton mr spectroscopy . \n the study on the largest number of cases ( n = 64 ) reported that the evaluations after 2 courses of therapy were more accurate than the evaluations after 1 course or after 3 courses . \n we conducted a study to determine whether proton mr spectroscopy or pet / ct is more suitable for early prediction of efficacy , and we conducted it after two courses of chemotherapy when prediction of efficacy by pet / ct also was reported to be the most accurate . \n the results of the study by the external reference method with a fixed voxel size ( 15 15 15 mm ) in 16 cases showed that proton mr spectroscopy and pet / ct were equivalent . \n however , whether mr spectroscopy is as good as pet has not been firmly established . \n neoadjuvant chemotherapy usually consists of an anthracycline - based regimen followed by taxane - based regimens , but because the early evaluations by mr spectroscopy are no more than evaluations of the initial anthracycline - based regimen and are not always consistent with the pathological evaluation after the completion of chemotherapy , evaluations of efficacy performed during the initial anthracycline - based regimen alone are inadequate for early prediction of the efficacy of this method . \n although the number of cases has been small , there have been cases in which the anthracycline - based regimen was ineffective , but the efficacy of subsequent taxane - based regimens was excellent , and cases in which the opposite was true . \n we therefore assessed early prediction of efficacy by mr spectroscopy in which treatment with an anthracycline - based regimen alone was performed , and the results indicated that the changes in choline after the second cycle of chemotherapy as determined by quantitative mr spectroscopy may be a more sensitive means of predicting the pathological response than changes in tumor size are . \n we think that it is preferable to try making early predictions of the efficacy of neoadjuvant chemotherapy for each of the individual drugs . \n based on the results described above , proton mr spectroscopy may not be inferior to pet / ct as a diagnostic method for early prediction of efficacy in breast cancer . in the next step \n , it will be necessary to determine whether it is possible to predict efficacy by proton mr spectroscopy earlier than after 2 courses . in a study on 14 cases , meisamy et al . \n found that the changes in the amount of choline detected at 4 t within the first 24 hours after a single course correlated with clinical efficacy after the completion of chemotherapy . \n we showed that the results of an evaluation by proton mr spectroscopy at 1.5 t after one course ( several days before the start of the second course ) correlated with pathological size after the completion of chemotherapy . \n however , the same as in the study by pet / ct , it was also possible to underestimate the efficacy of treatment after one course more than after two courses . \n proton mr spectroscopy is a technique that is still in the development stage in the breast disease . in the future \n , it will be necessary to carefully evaluate the proper timing of early prediction of the efficacy of chemotherapy because the underestimated data could be an obstacle to clinical application . \n the very basis of the spectroscopy method relies on the use of magnets with higher field strength to separate the diagnostic resonances . with the growing availability of 3 t systems , the use of breast mr spectroscopy for diagnosing lesions and monitoring response to neoadjuvant chemotherapy will become routine clinical practice . \n however , as stated above , there have not been very many reports on differential diagnosis between benign and malignant lesions or on early prediction of the efficacy of neoadjuvant chemotherapy . \n the reason is that many problems must be resolved , including the optimal measurement sequence for proton mr spectroscopy , differences between mr units , spectrum interpretation , postprocessing adjustments , and methods of choline quantification ( internal reference method or external reference method ) . \n however , if these problems are not resolved , it will be impossible to ensure the safety and reliability of being able to use it for cancer treatment ( drug therapy ) .", "role": "user" }, { "content": "proton mr spectroscopy of the mammary gland area is used to be considered in the realm of basic research , but as a result of the advances in mr techniques , it is now being performed in ordinary clinical practice . \n it is particularly noteworthy that useful clinical data are now being accumulated with 1.5 t mr units , which are the standard units . \n we think that , at this point , it is very important to systematically review the techniques , clinical applications , and future prospects of proton mr spectroscopy . \n we have performed proton mr spectroscopy with a 1.5 t mr unit in over 3000 cases at our hospital . in this paper \n , we will comment on the current status of proton mr spectroscopy of the breast , primarily in regard to differentiation between benign and malignant lesions and prediction of the efficacy of chemotherapy while describing the data obtained at our hospital .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: we report a case of congenital unilateral absence of the vas deferens found incidentally during vasectomy in a patient with known unilateral renal agenesis . \n following successful right vasectomy , several attempts to locate the left vas deferens were unsuccessful . \n as vasectomies are increasingly performed in outpatient settings , it is imperative that physicians be aware of this condition , which can be recognized by a simple physical exam . \n congenital unilateral absence of the vas deferens ( cuavd ) was first described by john hunter in 1737.1 reverdin in 1870 described the association between vas deferens agenesis and ipsilateral renal agenesis.2 cuavd is an uncommon entity with a reported prevalence range of 0.5%1% in the male population . \n as vasectomies are being increasingly performed by family medicine physicians they may encounter this condition more frequently . \n awareness of this condition would help uncover coexisting anomalies.3 we present a case of cuavd which was found incidentally during a vasectomy in a patient with ipsilateral renal agenesis . \n written consent was obtained . during the procedure the patient was locally anesthetized with 1% xylocaine . \n his right vas deferens was palpated ; a small transverse incision was made in the upper midline region of the scrotum . \n the right vas deferens was isolated , doubly clamped and the intervening segment excised and sent for pathology , which subsequently confirmed it as the vas deferens . \n after hemostasis was achieved the left hemiscrotum was palpated , however the vas deferens was not identified . \n a structure thought to be the atrophic vas deferens was isolated , doubly clamped and the intervening segment sent for pathology ; however , frozen section revealed it to be a blood vessel . \n after suturing the blood vessel and closing the incision , an incision was made 2 cm away where the left vas deferens was thought to be palpated ; however , it turned out to be the stitches placed on the previously mentioned blood vessel . \n he returned for follow - up two months later , at which time his incisions had healed and he was doing well . \n the patient was not tested for cystic fibrosis trans membrane conductance regulator ( cftr ) gene mutation as he had completed his family and there was no risk of further genetic transmission . \n cuavd is a rare entity and has an incidence of 0.5%1% in the male population as described above.3 it is commonly discovered either during an evaluation for infertility or during a vasectomy.4 about 0.06%0.8% of the patients undergoing vasectomy have cuavd.3 cuavd occurs twice as commonly on the left as compared to the right side . \n patients who were not fertile had a partially obstructed contralateral vas deferens but normal upper urinary tracts.3 renal agenesis is more commonly associated with unilateral vasal agenesis ( 73.7% ) compared to the bilateral form ( 11.8%).3 cuavd occurring with renal agenesis is due to an intrinsic wolffian duct defect . in the embryo , \n the vas deferens arises from the wolffian duct , which connects the mesonephros and the urogenital sinus . \n the ureteral bud arises from the wolffian duct as it curves to enter the cloaca . \n the penetration of the metanephrogenic blastema by the ureteric bud induces the development of the kidney . \n any interruption of this process before the complete separation of the wolffian duct and ureteric bud can result in renal agenesis and cuavd whereas interruption in the development of the wolffian duct after the separation may lead to an isolated unilateral absence of the vas deferens.2 other renal anomalies associated with cuavd are malrotation of the solitary kidney , multicystic kidney , ectopic kidney , and horseshoe kidney.5 anomalies of the seminal vesicles , ejaculatory ducts , cryptorchidism , and inguinal hernia have also been reported in association with cuavd.4 rare cases of vesicoureteric reflux and ureterovesical obstruction in the contralateral kidney have also been described.3 ipsilateral agenesis of the adrenal glands has also been reported occurring with renal agenesis and absence of the vas deferens.6 about 1%2% of males investigated for infertility have congenital vasal agenesis.3 most of these cases are due to bilateral vas agenesis ( 1%6% ) . \n the infertility in cuavd patients is often due to obstruction of the contralateral vas deferens.3 casals et al showed that 38% of congenital unilateral absence of the vas deferens cases are associated with mutations in the cftr gene.7 about 45% of these mutations were specific to congenital absence of the vas deferens ( cavd ) and were not found in cystic fibrosis patients . \n the ola / pcr mutation detection system which detects 31 different cystic fibrosis mutations identified only 26% of the cftr mutations in cavd patients . \n previous studies had found low association between renal agenesis and cftr mutations . according to the authors , the extensive cftr gene analysis done in place of the routine screening might have been responsible for the increased detection of cftr mutations in cuavd patients.7 cftr gene analysis should be offered to cavd patients with infertility planning to have children using assisted reproductive techniques as there is a risk in the offspring to have cystic fibrosis or related diseases.8 cavd may be tentatively diagnosed in the absence of the firm , round , sliding linguini - like vas deferens that sits in continuation with the epididymis and can be followed to the external inguinal ring on palpation.3 vasography or transrectal ultrasonography can also be utilized to visualize a missing segment of this structure . however , before diagnosing cavd , a scrotal exploration under general anesthesia is recommended.4 as shown by weiss , considerable delay ( 4.3 years on average ) can occur before cavd is diagnosed.5 this can potentially lead to increased mortality and morbidity associated with renal anomalies . \n therefore , palpating the vas deferens should be a part of the routine physical exam in males . \n patients diagnosed with cavd should be encouraged to undergo an abdominal ultrasound study to detect any other coexisting abnormalities.3,4 conversely , patients with known renal agenesis should also be evaluated for anomalies of the vas deferens . \n as vasectomy is the most common method of sterilization , it is essential that providers be aware of this condition and its associated abnormalities . \n palpation of the vas deferens should be included as a part of the routine physical exam in males .", "role": "user" }, { "content": "backgroundcongenital unilateral absence of the vas deferens occurs in 0.5%1.0% of males . \n it has been associated with various genitourinary abnormalities , including renal agenesis . \n we report a case of congenital unilateral absence of the vas deferens found incidentally during vasectomy in a patient with known unilateral renal agenesis.case presentationa 24-year - old male presented to our urology clinic requesting vasectomy . \n his past history was significant for left renal agenesis . \n following successful right vasectomy , several attempts to locate the left vas deferens were unsuccessful . \n we diagnosed congenital unilateral absence of the vas deferens . \n follow - up semen analysis showed azoospermia.conclusionas vasectomies are increasingly performed in outpatient settings , it is imperative that physicians be aware of this condition , which can be recognized by a simple physical exam . \n recognition could prevent unnecessary surgery and prompt providers to investigate for associated abnormalities .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: metastatic non - small - cell lung cancer ( nsclc ) is an invariably lethal disease with poor prognosis and with a 5-year survival rate below 5%.1 the standard first - line therapy for advanced nsclc not characterized for epidermal growth factor receptor ( egfr ) or anaplastic lymphoma kinase ( alk ) translocation is represented by platinum - based combination therapy , which prolongs survival , controls symptoms , and improves quality of life versus best supportive care in patients with good performance status.2 first - line treatment with an egfr tyrosine kinase inhibitor ( tki ) , such as erlotinib hydrochloride ( tarceva ; hoffmann - la roche ltd , basel , switzerland ) , gefitinib ( iressa ; astrazeneca , london , uk ) or afatinib ( gilotrif ; boehringer ingelheim gmbh , ingelheim , germany ) , is recommended in patients harboring activating egfr mutations . \n patients with alk rearrangements are candidates for a therapy with crizotinib ( xalkori ; pfizer , new york , ny , usa ) , a dual mesenchymal epithelial transition factor ( met ) and alk inhibitor . \n unfortunately , irrespective of tumor biology and therapy , all patients inevitably develop resistance to any available therapy , with a median progression - free survival ( pfs ) of 6 months with platinum - based chemotherapy and 812 months for targeted therapies.2,3 few effective second - line treatment options are currently available , including pemetrexed in patients with non - squamous histology , and docetaxel or erlotinib , irrespective of histology or egfr status.4 the effect on survival of second - line therapies is generally poor , with the only exception of egfr - tkis in patients with egfr mutations , or crizotinib in individuals with alk rearrangement only in patients in which these agents were not used as front - line therapy.58 hence , there is an urgent need for new , effective , and well - tolerated therapies for nsclc , particularly in the second - line setting . \n in addition to the targeted therapies mentioned above , recent insight into the molecular biology of cancer and mechanisms of tumorigenesis suggested the angiogenesis as a promising target for nsclc treatment . \n the development of inhibitors of angiogenesis , also known as vessel - directed cancer treatments , has become , over the last few years , a major challenge . \n there are two different types of vessel - directed cancer treatments : the vascular targeting agents and the vascular disrupting agents . \n the first group belong the antiangiogenic drugs , such as the anti - vascular endothelial growth factor ( vegf ) monoclonal antibody bevacizumab ( avastin ; genentech - roche , south san francisco , ca , usa ) , and the vegf receptor ( vegfr ) tyrosine kinase inhibitors , such as sunitinib ( sutent ; pfizer , new york , ny , usa ) and sorafenib ( nexavar ; bayer healthcare pharmaceuticals , leverkusen , germany ) . \n the vascular targeting agents inhibit the formation of additional vessel from existing vasculature , mainly at the outer edge of a growing tumor , and also normalize the constitutively complex network of tumor vasculature , potentially improving the delivery and efficacy of chemotherapy.9 bevacizumab , in combination with platinum - based chemotherapy , has been shown to improve survival versus chemotherapy alone in a first - line setting in patients with non - squamous nsclc10,11 and currently is the only antiangiogenetic drug approved by several regulatory agencies . \n in contrast , vascular disrupting agents ( vdas ) are directed against existing vessels , mainly in the tumor center,12 enhancing the cytotoxicity of chemotherapy and ionizing radiation , of which efficacy is decreased by interstitial pressure and hypoxia . although currently under worldwide clinical investigation , these drugs are not approved for cancer treatment.13 vdas can furthermore be divided into two classes : small molecules and ligand directed drugs . \n small molecules act as microtubule destabilizers and cytokine inducers , while ligand - directed drugs target specific markers of malignant vasculature . \n bavituximab is a vascular disrupting agent with a unique mechanism of action resulting in a high degree of specificity for tumor blood vessels.14 specifically , bavituximab is an unconjugated , chimeric immunoglobulin g1 ( igg1 ) monoclonal antibody directed against the phosphatidylserine ( ps ) , an anionic membrane phospholipid expressed on tumor endothelium . \n physiologically , ps is present in the membranes of all eukaryotic cells and involved in signalling , mainly in an extracellular context such as during apoptosis . \n ps is not evenly distributed throughout all cellular membranes , nor equally distributed between leaflets of a membrane bilayer . in healthy cells \n ps is restricted to the inner membrane leaflet , thanks to adenosine triphosphate ( atp)-dependent aminophospholipid translocases that catalyze the transfer from the external to the internal plasma membrane.15 several pathophysiologic processes , such as apoptosis , cell activation , and transformation , determine the external exhibition of ps,16 due to aminophospholipid translocases inactivation , or scramblases and abc floppases activation.17 once external , ps acts as one major eat me signal , ensuring efficient recognition and uptake of apoptotic cells by phagocytes and promoting the secretion of such anti - inflammatory cytokines as interleukin-10 and transforming growth factor beta ( tgf- ) . \n hypoxia and acidity , typical tumor characteristics , also trigger these processes due to the generation of the reactive oxygen species . subsequently , ps exposure could be considered a feature of cancer cells and tumor vessel endothelium.18 because of their large size and hydrophilic nature , monoclonal antibodies such as bavituximab do not pass through the plasma membrane and are unable to recognize and bind intracellular targets , an event that is possible once ps is external . specifically , bavituximab binds ps when recognizing a complex formed by ps and two cross - linked molecules of the ps - binding protein beta 2 glycoprotein-1 ( beta 2gp1).19 \n bavituximab , once bound , starts up host effector activities such as antibody dependent cellular cytotoxicity , causing vessel destruction and enhancing antitumor immunity . \n relevant preclinical studies have been conducted with 3g4 , a mouse immunoglobulin g3 monoclonal antibody similar to bavituximab that specifically recognizes anionic phospholipids.17 histologic examination of orthotopic human mda - mb-231 tumors from mice treated with 3g4 revealed a significant reduction of neoplastic vascular density and plasma content.20 localization of 3g4 to tumor vessels preceded macrophage binding to tumor vessels , impairment of vascular function , and development of necrosis . \n the central necrosis with a peripheral circle of surviving tumor cells is a characteristic pattern of tumor cell killing by vascular targeting agents . indeed , vascular targeting agents are thought to be most effective against central vessels , where the high interstitial pressure contributes to vascular collapse , contrary to many anticancer therapies which are effective in the well - oxygenated and peripheral areas of the tumor . \n combining vascular targeting agents with antiproliferative antitumor therapies could thus have an additive or even synergistic antitumor activity . \n moreover , histologic examination revealed a marked presence of blood monocytes to tumor vascular endothelium and profuse infiltration of macrophages into the tumor interstitium , consistent with the fact that 3g4 enhances the rate of phagocytosis of phosphatidylserine - expressing cells by bone - marrow derived mouse macrophages in a fragment crystallizible ( fc)-dependent fashion.21 taken together , these aspects could raise the possibility that 3g4 causes macrophage cytotoxicity against tumor vessels or tumor cells in mice indirectly , suggesting that the antibody is not directly cytotoxic . \n two mechanisms of macrophage - mediated damage to tumor vessels or tumor cells seem feasible . \n firstly , 3g4 may bind to exposed anionic phospholipids on tumor vessels and tumor cells , stimulating the binding of monocytes and macrophages via fragment crystallizible gamma ( fc - g ) receptors and enhancing antibody dependent cell - mediated cytotoxicity . \n secondly , 3g4 may block phosphatidylserine - mediated quiescence signals , inducing macrophages to secrete tumor necrosis factor- , interleukin-1 , and other inflammatory cytokines that directly damage tumor endothelium and recruit further host cells into the tumor.20 in addition , bavituximab provides anticancer effects by reversing the immune and inflammatory suppression exerted by tumors . \n if exposed , ps reduces the production of proinflammatory cytokines while ps targeting counteracts these processes , promoting proinflammatory pathways , recruitment of tumoricidal m1 macrophages , dendritic cell maturation , and antigen presentation.17 as ps performs a crucial role in the binding and activation of coagulation factors , a careful screening for an increased bleeding or thrombogenic risk has been conducted from the first studies . unlike the pathologic antiphospholipid autoantibodies directed against cardiolipin and beta 2 glycoprotein-1 ( beta 2gp1 ) , bavituximab targets domain ii of beta 2gp1 \n , preserving its circulating and inactive conformation not correlated with antiphospholipid antibody syndrome in preclinical models.22 however , bavituximab prolongs activated partial thromboplastin time ( aptt ) assays in vitro due to the binding to the phospholipid activator in the assay . \n transient prolongations in the aptt were evidenced in rats at bavituximab doses 20 mg / kg ( corresponding approximately to a maximum concentration [ cmax ] of 345 g / ml ) . based on these results in the first phase i trial of bavituximab , conducted on 26 pretreated cancer patients , \n dose escalation was capped at 3 mg / kg ( simulated cmax in humans = 65.4 g / ml).23 all six patients treated at the 3 mg / kg dose experienced a transient aptt prolongation and none in lower dose levels . in all patients , the aptt normalized by day three following the bavituximab dosing , consistent with the half - life of bavituximab . \n an increase in d - dimer level was evidenced in about half the patients , not temporally associated with the drug administration and not predicting thrombotic occurrences . \n twenty - five patients ( 96% ) had assessment of platelet function by platelet function analyzer 100 ( pfa-100 ) analysis . a prolongation of normal baseline pfa-100 after bavituximab administration occurred in one patient in the 3 mg / kg dose cohort . \n platelet activation markers , as pac-1 and p - selectin , were unchanged in response to bavituximab therapy in the two patients evaluated . \n the pharmacokinetics of bavituximab have been assessed in a recently published phase i open - label , dose - escalation trial.23 the dose levels selected were 0.1 , 0.3 , 1 , and 3 mg / kg , with a starting dose defined on the basis of single- and repeat - dose rodent and primate toxicity studies , and efficacy data obtained in a tumor bearing mouse model . \n dose escalation to the biologically effective dose rather than the maximum tolerated dose ( mtd ) was the goal of this study . \n this approach takes into account that for monoclonal antibodies the mtd may not correspond to optimal efficacy and , in some instances , may never be reached in monotherapy studies.24 in animal models , maximal efficacy of anti - ps antibody was achieved at doses of 0.5 mg / kg 3 times weekly , yielding a cmax of 5.5 mg / ml with a half - life of 48 hours and a simulated average blood concentration of 2 mg / ml . overcoming this dose , ps binding was presumably saturated , in line with the in vitro evidence of ps - expressing cell saturation at 1 to 2 mg / ml bavituximab concentration . moreover \n , aptt transient elevations were noted in rats at bavituximab doses of 20 mg / kg or more ( cmax 345 mg / ml ) . \n therefore , capping the dose escalation at 3 mg / kg ( with simulated cmax in humans of 65.4 mg / ml , corresponding to an equivalent cmax of 11111 mg / ml in rodents ) guaranteed a more than 5-fold safety value , providing drug concentrations over the therapeutic range . accordingly with the defined dosing schedules , bavituximab was infused to patients in the first two dose cohorts ( 0.1 and 0.3 mg / kg ) on day 0 , followed by a 28-day washout , and then once weekly for three weeks ( on days 28 , 35 , and 42 ) , following patients until day 70.23 the study was subsequently amended avoiding the 28-day washout . \n thus , patients in the 1 and 3 mg / kg dose cohorts have been treated with bavituximab on days 0 , 7 , 14 , and 21 and then followed until day 56 . \n dose escalation was permitted if dose - limiting toxicity ( dlt ) occurred in one or none of six patients and serum bavituximab levels did not exceed a predetermined threshold . \n the mtd was defined as the highest dose level at which a dlt was experienced in less than 33% of patients . \n dlts were defined as any of the following adverse events observed through day 56 or 70 ( depending upon cohort ) : grade 3 or greater hematologic or non hematologic toxicity , grade 2 or greater prolongation of prothrombin time / international normalized ratio ( pt / inr ; > 1.5 upper limit of normal [ uln ] to 2 > uln ) , grade 3 or greater prolongation of aptt ( > 2 uln ) . \n bavituximab exhibited linear single - dose ( day 0 , for all cohorts ) and multiple - dose ( for the 1 and 3 mg / kg cohorts on day 21 ) pharmacokinetic characteristics . after time to peak concentration ( tmax ) , \n mean serum bavituximab concentrations seemed to decline in a monoexponential manner , with similar concentrations on days 0 and 21 within dose groups with a half - life of approximately two days , somewhat shorter than that of other chimeric ( ie , 65% human and 35% mouse ) antibodies such as cetuximab ( half - life four days ) . \n this difference could be correlated with the clearance of b2gp1 as bavituximab s target : differently from soluble targets such as vegf , ps is static and saturable , so bavituximab levels may not necessarily need to be maintained over a prolonged period . whereas all patients experienced at least one adverse event , the most frequent were fatigue ( 27% ) , nausea ( 15% ) , aptt prolongation ( 12% ) , and pyrexia , rash , and dyspnea ( each 8% ) , mainly grade 1 or 2 and occurring with similar frequency across dose cohorts . \n ten patients ( 38% ) showed at least one grade 3 or 4 adverse event . \n one patient experienced a pulmonary embolism considered related to treatment in the 3 mg / kg dose cohort , and was the only dlt observed in the study . \n another patient in the 3 mg / kg dose cohort developed grade 3 hypertension considered not causally related to bavituximab . \n the authors concluded , therefore , that bavituximab can be safely administered weekly , with low risk of infusion reactions . on the basis of sustained achievement of predicted therapeutic concentrations , both the 1 and 3 mg / kg doses \n are recommended for subsequent monotherapy and combination trial with a close clinical monitoring for thromboembolic phenomena and laboratory monitoring for antiphospholipid effect , in consideration of the case of pulmonary embolism that occurred . \n clinical data regarding the efficacy of bavituximab was initially derived from the aforementioned phase i study . of the 26 patients enrolled and affected by cancer of the breast ( n=13 ) , colorectal ( n=4 ) , pancreas ( n=3 ) , and hepatocellular , head and neck , melanoma , mesothelioma and prostate ( n=1 each ) , 18 were evaluable , presenting as eight stable disease and ten progressive disease , according to revised response evaluation criteria in solid tumors ( recist ) guideline ( version 1.1 ) recist criteria . \n there were no objective responses , similarly to efficacy data regarding other vascular targeting monoclonal antibodies . in subsequent phase \n ib , which enrolled 14 patients with refractory advanced solid tumors , bavituximab ( b ) was given weekly for up to 8 weeks , at a dose of 3 mg / kg , in combination with docetaxel ( d ) ( 7580 mg / m every 3 weeks ) or gemcitabine ( g ) ( 1,000 mg / m in weeks 17 ) , or paclitaxel ( 175 mg / m every three weeks ) plus carboplatin ( appropriate use criteria [ auc ] = 5 ) ( p + c ) . \n study objectives were to evaluate the safety , tolerability and pharmacokinetic profile of b when combined with chemotherapeutic agents . \n serum levels of b were determined by enzyme - linked immunosorbent assay ( elisa ) . \n five patients received b + d , five patients received b + g , and four patients received b + p + c. the most common adverse events were vomiting ( six patients ) , cough ( four patients ) , asthenia , pain , headache , neutropenia , prolonged aptt , and pain in extremities , each in three patients , with three serious adverse events ( saes ) considered related to b. in accordance with recist criteria , among the twelve evaluable patients there was partial response ( three patients ) , stable disease ( three patients ) , and progressive disease ( six patients ) . regarding the pharmacokinetic profile , no significant differences were seen between the three treatment groups following administration of b on days 0 and 21 ; no accumulation of b was seen following multiple dose administration.25 on the basis of these results ( table 1 ) , a randomized , blinded , placebo - controlled phase ii trial of d plus b as second - line treatment in locally advanced or metastatic nsclc patients was conducted.26 one hundred and twenty - one patients were randomized 1:1:1 to receive d at 75 mg / m every 21 days for up to 6 cycles in combination with blinded infusions of placebo ( p ) , b at 1mg / kg , or b at 3 \n the primary endpoint was overall response rate ( orr ) , while secondary endpoints were progression - free survival ( pfs ) and overall survival ( os ) . \n after the study unblinding , a pharmacokinetic predefined analysis revealed phial coding discrepancies in the placebo and b at 1 mg / kg phials ; consequently data from these two cohorts were pooled forming the control arm ( c arm ) . between the 41 patients treated with b at 3 mg / kg plus d , representing the experimental arm , and the other 80 patients into the c arm , there were no significant differences in age , sex , ethnicity or disease stage . \n available data , collected at 54% of death events reported in the experimental arm and 71% in the c arm , demonstrated 17.1% and 13.8% orr , respectively . \n regarding secondary endpoints , median pfs was 4.5 months and median os was 11.7 months for 3 mg / kg b + d arm ; median pfs was 3.3 months , and median os was 7.3 months for c arm ( table 2 ) . \n the safety profile for 3 mg / kg b + d was similar to that of c arm in severity and frequency , representing the planned dose for the phase iii trial . the sunrise ( stimulating immune response through bavituximab in a phase iii lung cancer study ) \n is the phase iii global , randomized , double - blind , placebo - controlled clinical trial , recently opening to enrollment in more than 100 clinical sites worldwide , which randomized , in 1:2 fashion , to bavituximab plus docetaxel versus docetaxel plus placebo as second line in approximately 600 patients with stage iiib / iv non - squamous nsclc . \n all patients will receive up to six 21-day cycles of docetaxel ( 75 mg / m ) plus weekly infusions of either bavituximab ( 3 mg / kg ) or placebo until progression or toxicity . \n bavituximab was granted the fast track designation by the us food and drug administration ( fda ) for the potential treatment of second - line nsclc . \n bavituximab has also been studied in the frontline setting . in a phase ii trial27 which enrolled 49 indian patients with untreated locally advanced or metastatic nsclc \n , the antibody , at a weekly dose of 3 mg / kg until disease progression , was tested in combination with carboplatin and paclitaxel , at a dose of auc = 5 and 175 mg / m , respectively , on day 1 up to six 21-day cycles . \n the study used a simon 2-stage design and demonstrated an orr ( complete response + partial response ) in the initial group of 11/21 ( 52.4% ) , with clinical complete response in 4.8% and partial response in 47.6% . according to available data , \n median pfs in the first 21 patients treated is 6.2 months ; median duration of response and median overall survival have not yet been presented . \n adverse events ( aes ) have been reported by 44/49 ( 89.8% ) treated subjects , the most common being pyrexia ( 28.6% ) , diarrhea ( 26.5% ) , alopecia ( 26.5% ) , anemia ( 22.4% ) , neuropathy ( 20.4% ) , and pain ( 20.4% ) with mild or moderate severity . \n forty - five saes have been evidenced in 19 subjects , including two deaths due to myocardial infarctions and one death due to hemoptysis , which occurred in a subject with squamous histology , whereupon the accrual of squamous cell carcinoma ceased . on the basis of the promising result of 52% orr using recist criteria in an initial group , \n the combination with carboplatin and paclitaxel has been evaluated in a recently - concluded phase ii randomized trial ( nct01160601 ) , which accrued a total of 86 subjects in the united states , the republic of india , the republic of georgia , the russian federation , and ukraine . \n the trial randomized patients with up to six cycles of carboplatin ( auc = 6 ) plus paclitaxel at 200 mg / m with or without bavituximab 3 mg / kg weekly until intolerable toxicities or disease progression . \n another combination , specifically carboplatin , pemetrexed and bavituximab , is studied in the same setting in a recently opened phase i trial ( nct01323062 ) . \n angiogenesis , thanks to progressive insight into the molecular biology of cancer and mechanisms of tumorigenesis , is a promising target for nsclc treatment , and the development of vessel - directed cancer treatments has grown enormously in recent years . \n these treatments can be divided into two different classes : the vascular targeting agents ( such as bevacizumab , the only antiangiogenetic drug today approved for nsclc treatment ) , and the vascular disrupting agents such as bavituximab . \n bavituximab is a an unconjugated , chimeric immunoglobulin g1 ( igg1 ) monoclonal antibody directed against the phosphatidylserine ( ps ) expressed on tumor endothelium and segregated to the inner membrane leaflet . \n once exposed on the external membrane , due to various pathophysiologic processes , ps can be bound by bavituximab , which starts up host effector activities such as antibody dependent cellular cytotoxicity , resulting in vessel destruction and enhanced antitumor immunity . \n on the basis of promising preclinical activity and an acceptable safety profile , bavituximab is currently under investigation in combination with chemotherapy for advanced nsclc in several trials . \n the second - line setting studies are of particular clinical interest . specifically , a recently presented phase ii randomized , placebo - controlled trial of bavituximab plus docetaxel suggested a positive trend favoring the combination , with orr of 17% , median pfs more than 4 months , and median os more than 11 months . these results , although initial and needing confirmation by the currently ongoing phase iii trial , are promising and similar to data recently published with docetaxel plus nintedanib , an oral angiokinase inhibitor , in the same setting.28 this latest trial demonstrates a significant os benefit , thus is different from other antiangiogenic compounds that have been tested in the second - line setting , such as vandetanib,29 sunitinib,30 or aflibercept,31 despite pfs improvements . in view of the hypothetical association of antiphospholipid antibody syndrome with cases of thrombosis and bleeding occurring in earlier studies , \n a principal limitation of available studies is the lack of biomarker data , which represents an urgent major challenge . \n although in vitro aptt prolongation provides some pharmacodynamic data , the association between this laboratory finding and therapeutic effect is not known . to provide more insight into the mechanism of bavituximab in humans , dynamic contrast \n enhanced magnetic resonance imaging ( mri ) scans could be incorporated into selected ongoing and future bavituximab clinical trials . \n similarly , the available studies did not include biomarkers of antitumor immunity , which represents another proposed mechanism of bavituximab therapeutic effect . in conclusion , available data regarding the use of bavituximab for the treatment of metastatic and refractory nsclc make an important contribution in cancer treatment research by adding another agent to the armamentarium of drugs . \n it is hoped that the use of more comprehensive study designs incorporating tissue- , blood- , and imaging - based assays will result in even more clinically relevant results .", "role": "user" }, { "content": "bavituximab is a an unconjugated , chimeric immunoglobulin g1 ( igg1 ) monoclonal antibody directed against the phosphatidylserine ( ps ) expressed on tumor endothelium , with a specific mechanism of action . \n ps is an anionic membrane phospholipid , physiologically restricted to the internal membrane leaflet ; various pathophysiologic processes cause the exposure of ps on the external membrane leaflet . \n bavituximab , once bound , starts up host effector activities , such as antibody dependent cellular cytotoxicity , causing vessel destruction and enhancing antitumor immunity . \n phase i clinical trials of bavituximab administered as monotherapy or in combination with other chemotherapeutic agents in adults with pretreated solid tumors have been accomplished , indicating that bavituximab can be safely dispensed weekly , with a recommended dose of 1 and 3 mg / kg . a phase ii randomized , placebo - controlled trial of bavituximab plus docetaxel , in the second - line therapy setting of locally advanced or metastatic non - small - cell lung cancer , has been conducted and recently presented , suggesting a clinical benefit of the combination , with an overall response rate of 17% and median overall survival of more than 11 months . \n a phase iii trial is currently ongoing . \n bavituximab has been studied in combination with platinum - based doublets with promising results . in the present paper \n we summarize the preclinical development and clinical experience with bavituximab in non - small - cell lung cancer .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: in terms of social aspects , cancer disturbs daily functions and social activities of the sufferer , and alters his or her abilities to fulfill their normal roles and responsibilities , up to an extent that creates some new roles . \n the nature of the new - born roles may cause a feeling of inefficiency and social isolation in the sufferer . \n in fact , after cancer is diagnosed , the patient will be hit by a crisis , his self - confidence will be at stake , his individual relationships will be disturbed due to uncertainty about future , the previous adaptation mechanisms will seem insufficient , and being hospitalized repeatedly , the patient will be flooded with solitude . a set of factors mentioned above lead to psychological stress in the patient .cancer is a prevailing , chronic , non - infectious disease . \n the exact reason is unknown , but genetic and exterior factors like viruses and carcinogen chemicals are likely to be influential . taking anti - cancer medicines and chemotherapy are some treatments for tumors , though they can be mixed with operation and radiotherapy . \n chemotherapy is very effective in treating tumors , and the effect is increasing nowadays by implementing newly - discovered anti - tumor medicines . conducted studies indicate that cancer is the second cause of americans death after cardiovascular diseases . as an effective treatment for increasing life - expectancy in the patients \n research shows that the patients get stressed before chemotherapy , and it causes body resistance against treatment and disturbs the process . \n having done a set of tests about breast cancerous cells , researchers have found out that the protein created after stress helps the cancerous cells continue living , getting adapted and resisting against the treatment . \n research has shown that immune system is effective in controlling and healing cancer , in other words , a weakening immune system raises the potentials to develop various types of cancer . \n stress has been discussed as a suppressing factor of the immune system , so there is a possibility of cancerous cell growth after stress . \n one of non - medical ways of stress reduction is laughing and being in delightful environments . \n laughter is a positive sensation , and seems to be a useful and healthy way to overcome stress . \n decreasing stress - making hormones floating in blood , laughter removes the effects of stress . \n nowadays , there is evidence indicating that being humorous and exposed to funny stimuli can have a positive influence on the side - effects of some specific diseases . \n lidi maintains that fun and laughter decrease red globule sedimentation level and increase natural killer - cells activity , reduce cortisol and blastogene lymphocytes and boosts monoglobin a as well . \n fri ( 1971 ) declares that laughter strengthens the immune system , facilitates phagocytosis process in the immune system and also helps the body to fight against infections . \n dogan believes that biological functions of laughing and crying cause biochemical changes in the body and reduces the tension made by painful emotions like fear and anger \n . tears and nasal discharge during laughing and crying contain humorous , steroids and toxins accumulated in the body during tension . laughing and crying both increases coolamine production in the blood . \n a way to make people laugh is laughter yoga , innovated by kataria ( 1995 ) in india . \n laughter yoga is the only way enabling people to laugh heartily without getting involved in logical thinking . \n the reason the cataria named his innovative method as laughter yoga was that he had mixed the respiratory exercises of yoga -called paranayama- into laughter exercises . \n the former exercises are very strong and effective , and they have been applied for thousands of years to influence human body , psyche and emotions in a positive manner . based on yoga philosophy , our life is subject to a flow of universal energy into our bodies via breathing . \n , our respiration gets irregular and shallow , and this disturbs the flow of energy in our bodies . \n it should be noted that the studies on this domain have examined laughter effects using the mentioned methods and other variables reducing stress , and all of these studies have regarded the long - term effects of laughter , while the short - term effects of laughter on the stress in patients with cancer is being dealt with in the current research using laughter yoga . \n therefore , in this study , the question is if laughter yoga is effective on cancer - sufferers stress level before chemotherapy . \n statistic population of the research was patients hospitalized in shohada tajrish hospital for chemotherapy in the period of may to august , 2013 . \n table 1 shows distribution of samples in terms of groups , education and genders for sampling , those qualified patients were selected for trial , which were randomly placed in experimental and control groups . \n the minimum population of sample for each of control and experimental groups is 15 in semi - experimental studies . \n accordingly , researchers had initially selected 25 samples to avoid sample drop , 2 patients in experimental group and 11 in control group were omitted from the sample list in pre - test due to leaving the hospital , moving to other clinics or lacking interest for taking part in the research . there ultimately remained 23 patients in experimental group and 14 in control group . \n stress measuring questionnaire : questionnaire qsc - r23 ( questionnaire on stress in cancer patients ) was used in this research to measure stress ( the questionnaire is attached ) . \n this questionnaire is specially related to specific diseases and evaluates psychological stress in cancer sufferers . \n questionnaire articles were divided into 5 equal scales , including psych - physical complaints , fears , information defects , daily - life limitations and social conflicts . \n qsc was first formed in germany after passing different phases , namely exact interviews , examining the initial versions of the questionnaire and measuring their validity and constancy by herchbach . \n cronbach s alpha method of analysis was implemented to estimate tools constancy in the research . \n the answers to the questions included two parts : first , the article did not apply to the respondent ( zero degree ) , second , respondent s conditions conformed to the specifications in the article . \n if the second part was selected , the answer should have determined the degree to which the subject matter of that article was affecting him / her . \n this degree can be positioned on a scale of 1 ( very small problem ) to 5 ( very serious problem ) . \n first , qsc - r23 questionnaire was administered to the patients accompanied by exact and complete explanations about it , and they were asked to fill it out in the researcher s presence . in case patients were unable to fill out the forms , the researcher took responsibility herself . \n having the forms filled out in control and experimental groups , the experimental group was treated by laughter yoga by a trainer for 20 to 30 minutes under researcher s observation . \n after that , the tastes in both groups were asked to fill out the questionnaire again . \n having conducted the research , laughter yoga was performed in control group as well to conform to the ethics . \n the data obtained was then analyzed by descriptive statistic methods such as mean and deviation , and the multi - variable covariance analysis test was applied to examine the research hypothesis . \n according to table 2 , there is a meaningful difference between the pre - test and the post - test average ; however , in control group there is no difference between them . \n finally , the results of multivariate covariance analysis between variables in both experimental and control groups are shown in table 3 , in which there is no meaningful difference in psych - physical complaints , information defects and total stress score . \n findings show that the intervention was effective in making a meaningful difference in three sub - scales of psych - physical complaints , fear , information defect and total score of stress in the two groups . \n the result of this research is in line with silva , chaya and crew , marcon and beke , and contrary to omrani . \n according to the research , stress increases cancerous cells activity to a meaningful extent , and causes the involved cells to resist against chemotherapy . using a method to decrease \n the findings of the research have shown that as a natural gift , laughter can reduce the stress in cancer sufferers before chemotherapy . \n laughter plays an important role in reducing stress , which is done by endorphin secretion resulting in mental and physical relaxation . \n chronic stress impacts limbic system and hypothalamus continuously and leads to adrenaline secretion and causes disruption in immune system . indeed , laughter balances sympathetic and parasympathetic system ; moreover , it functions as an anti - stress . \n endorphin seems to be the most easily linked structure to morphine , both function in the exhilaration and lessening of pain . to illustrate this according to the study background , \n it can be noted that laughter not only creates good spirits in patients and the hospital staff , but also it can reduce the stress in patients and improve the treatment process without any harmful side - effects by creating a happy environment at hospitals . \n examining the data brings us to conclusion that laughter has a significant effect on the spirits of patients and their stress . \n in this study , the questionnaire qsc - r23 was applied as the measuring tool . it is strongly suggested that the study under the same title should be conducted using other tools , such as pulse and heart beat measuring in addition to self - reporting to undermine the effect of the samples on the result . \n moreover , according to the role of laughter in reducing stress , hospitals had better be equipped with laughter rooms . \n doctors and nurses must be trained to be on duty smiling , and finally , comedy shows should be played for the sufferers .", "role": "user" }, { "content": "backgroundcancer is usually accompanied by considerable stress for the sufferer , and the stress has destructive effects on chemotherapy treatment process . \n therefore , the current research deals with the effect of yoga laughter on the cancer patients stress before chemotherapy.methodsin this research , as the first step , 37 cancer sufferers , who had been hospitalized in shohada tajrish hospital ( behnam daneshpoor charity organization ) and had the requirements necessary for being taken as research samples , were selected for data collection . \n the mentioned patients were classified randomly in experimental and control groups . \n collected data were analyzed by the multi - variable covariance analysis test.resultsthe results show there is a meaningful difference in the stress average before and after interference in the test group ( p<0.05).conclusionlaughter yoga can decrease the stress in cancer sufferers before chemotherapy .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: since its first description in 1990 , transient apical cardiomyopathy ( also known as takot - subo - like left ventricular dysfunction ) has been recognized more frequently with the widespread use of echocardiography . \n it represents a unique model of stress - related , acute reversible ventricular dysfunction that mimics an acute coronary syndrome in the very early stages . despite multiple mechanisms suggested to explain its pathophysiology , there is increasing evidence that supports direct neuroadrenergic myocardial stimulation with concomitant transient , reversible , coronary vasospasm as the inciting event , either at the epicardial or arteriolar level \n recurrence is rare , and estimated to be less than 3.5% of all documented cases . \n intense , reciprocal input between the esophagus and coronary arteries has been well documented in both animal and human models . \n hence , we present the challenging case of a postmenopausal female with severe esophageal spasms , who presented with recurrent transient apical cardiomyopathy ( tac ) in the setting of emotional distress and probable coronary vasospasm . \n a 66-year - old woman with a history of av nodal ablation for atrial fibrillation and severe , diffuse esophageal spasms which required multiple dilations and surgical myectomy had been hospitalized multiple times at a nearby institution with shortness of breath and chest pain . \n most of her symptoms had been attributed to esophageal spasms confirmed by manometry . during her first admission , an echocardiogram demonstrated an ejection fraction of 25 - 30% with apical anterior , inferior and lateral wall akinesis , compatible with tako - tsubo - like cardiomyopathy . \n she underwent a coronary angiogram 48 h later with no evidence of obstructive disease and normalization of left ventricular function . \n she presented six months later to our hospital complaining of severe chest pressure that started abruptly after she became furious at her driver for being late . \n her ecg on admission [ figure 1a ] displayed a ventricular paced rhythm , with hyperacute t waves and new st segment elevation in anterior precordial leads ; she was given aspirin and started on heparin infusion . \n once intravenous infusion of nitroglycerin was initiated , she had resolution of her index symptoms , as well as most of her ecg changes [ figure 1b ] . \n echocardiogram performed the next morning [ figure 2 ] revealed an ejection fraction of 15% with apical ballooning , consistent with tako - tsubo - like cardiomyopathy . \n she received supportive management and was started on long acting nitrates and calcium channel blockers with no recurrence of symptoms . on admission day # 5 , her left ventricular function was reassessed by echocardiogram and noted to be within normal limits . \n ( a ) 12-lead ecg on presentation while the patient was experiencing angina , reveals a ventricular - paced rhythm with hyperacute t - waves in anterior precordial leads ( arrows ) , along with st segment elevation of more than 1 mm in those leads . \n ( b ) 12- lead ecg after initiation of nitroglycerin infusion ; the patient had resolution of angina symptoms . \n notice the reversal of acute changes in precordial leads as compared to fig 1a transthoracic echocardiogram with contrast that shows apical akinesis with a hyperkinetic base , consistent with transient apical ( tako - tsubo - like ) cardiomyopathy . \n in clinical practice , the diagnosis of transient apical cardiomyopathy with chest pain is usually achieved after exclusion of a typical obstructive acute coronary syndrome , since both entities share common elements , particularly during the early stages of presentation . defining features of tac include the sudden onset of new st and t wave abnormalities ( usually st elevation , t wave inversion or both ) in the setting of a stressor , mild elevation in cardiac enzymes , transient , disproportionate left ventricular dysfunction that does not follow a typical coronary distribution , and finally , absence of angiographic obstructive coronary disease that can explain the ventricular dysfunction . \n data from the caspar trial showed that as many as 25 % of patients who present with chest pain at rest suspicious for a coronary event have no evident culprit lesion ; furthermore , in this select group of patients , intracoronary challenge with acetylcholine ( ach ) is able to induce spasm in almost half of them . \n it has been noted that individuals with a persistently positive ach response have higher tendency for recurrent left ventricular dysfunction , and therefore use of ach becomes both a diagnostic and prognostic tool . \n unfortunately , our patient was not challenged during her first presentation when an angiogram was performed , which might have yielded a definitive , specific diagnosis early on . \n the combination of angiography with provocative testing , along with perfusion echocardiography has been proposed as a comprehensive strategy to characterize this subset of patients with non - obstructed coronaries [ figure 3 ] . \n the lack of consistent results in the literature regarding ach testing after tac could be due to variable timing of testing or dosing ; furthermore , the difference in angiographic response might be related to the location of susceptible coronary arteries ( epicardial arteries versus arterioles ) . \n the combination of provocative testing with simultaneous echocardiography could detect a subset of patients with vasospastic features and normal coronaries the pathophysiology of tac is likely multifactorial , and there is growing evidence to suggest that complex neuro - hormonal stimulation and endothelial dysfunction is responsible ; the initial mechanism appears to be neuroadrenergic stimulation of the myocytes under physical or emotional stress , resulting in myocardial stunning . \n vascular sympathetic stimulation at the epicardial and/or arteriolar levels can lead to severe , diffuse , and transient coronary vasospasm , which in turn aggravates left ventricular dysfunction and associated metabolic abnormalities [ figure 4 ] . \n diagram that summarizes the pathophysiology of left ventricular dysfunction seen in transient apical cardiomyopathy as a consequence of neuro - hormonal mediated myocardial stimulation galiuto and colleagues conducted an insightful protocol to assess the role of vasospasm in tac . \n they assessed a group of patients with evidence of tac by commonly accepted criteria ( n = 15 ) , including absence of epicardial obstructive disease , with a similar control group of patients ( n = 15 ) with an anterior stemi . \n both groups were studied using myocardial contrast echocardiography within 3 2 days of the onset of symptoms , at the time that an intravenous infusion of adenosine ( 140 ug / kg / min ) was administered . \n all myocardial functional variables ( wall motion score index , contrast score index , myocardial perfusion defect length ) significantly improved in the tac group , promptly returning to resting conditions after discontinuation of adenosine infusion . \n at one month follow - up , myocardial perfusion significantly improved when compared to baseline in tac subjects , but not in patients who sustained an anterior stemi . \n furthermore , the investigators were able to find a match between the extent of perfusion defects by echocardiography and the size of regional dysfunctional areas , both improved with vasodilation of probably non - obstructed or minimally - obstructive coronary arteries , responsive to adenosine . \n it is important to emphasize that during adenosine infusion , myocardial functional parameters did not completely normalize , suggesting that restoration of blood flow can partially improve contractile reserve of a metabolically stunned but viable myocardium . \n fatty acid metabolism also appears significantly impaired in tac , particularly during the early phase . \n timi frame count , an index of coronary flow velocity , has been noted to be significantly higher ( representing slower blood flow ) in all coronary arteries in patients with tac compared with controls , even after resolution of ventricular dysfunction . \n these clinical experiments strongly support the concept that irrespective of the original insult , early reversible vascular dysfunction is a common element in patients with tac . \n a notorious feedback loop has been documented between the coronary arteries and the esophageal system . \n coronary vasospasm can be elicited by stimulation of alpha - adrenergic , histaminic , serotoninergic and muscarinic receptors ; similarly alpha - adrenergic , histaminic and muscarinic receptors mediate esophageal contraction . \n patients with variant angina have been compared to symptomatic patients with obstructive cad and nocturnal angina , with the concurrent use of esophageal manometry and continuous ecg monitoring . in individuals with variant angina , episodes of esophageal spasms \n are clearly time related to periods of ecg - recorded ischemia ; bidirectional analysis of causal effects demonstrates that the influences are mutual and reciprocal . \n abnormal sympathetic stimulation could be a common trigger , which would be consistent with the neuroadrenergic hypothesis of myocardial stunning in tac . \n in clinical practice , this poses significant diagnostic challenges , as demonstrated in our case , since these patients with linked angina can present with atypical chest pain , at times attributable to the esophageal system , and others to transient coronary ischemia . \n it would be interesting to speculate if such reciprocal stimulation pathways exist between the coronaries and the bronchial tree in humans , since copd and asthma have been reported in a high percentage of patients with tac . \n there are no specific guidelines for the management of tac presenting with chest pain ; initial approach usually overlaps with that of an obstructive acute coronary syndrome , due to the inability to distinguish these entities on clinical or electrocardiographic grounds alone ; urgent angiogram is key to make such distinction in the acute setting . given current insight into the pathophysiology of tac \n , it appears reasonable that drugs that can alleviate vasospasm or blunt adrenergic response such as alpha - beta blockers , nitrates and calcium - channel blockers could prove beneficial in the process of supporting patients with this condition ; prospective comparative trials are needed to address this hypothesis . \n it is important to emphasize that despite its reversible nature , tac is not always a benign condition , particularly in the acute phase , when pulmonary edema , ventricular dysrhythmias and cardiogenic shock can significantly compromise patients . \n transient apical cardiomyopathy that presents with chest pain continues to be a challenging entity , given its similarities to an acute atherosclerotic coronary syndrome in its early phase . \n regardless of the initial insult , intense , neuroadrenergic myocardial stimulation with vasogenic and metabolic changes appears as the unifying mechanism that explains transient ventricular dysfunction . due to the reciprocal feedback between coronary and esophageal spasms \n , some patients might be predisposed to a form of linked angina , manifesting as a smooth muscle hyper - contractility syndrome .", "role": "user" }, { "content": "transient apical cardiomyopathy , also known as takot - tsubo - like left ventricular dysfunction , is a clinical syndrome characterized by reversible left ventricular dysfunction at the apex with preserved basal contractility , in the setting of new st and t wave changes suggestive of ischemia but no evidence of obstructive coronary artery disease on angiography . \n the main mechanism appears to be intense neuroadrenergic myocardial stimulation with endothelial dysfunction of the coronary vasculature . \n it has been noted that patients with esophageal spasms also have a tendency for coronary spasms . \n we present the case of a postmenopausal female with documented severe esophageal spasms who presented with atypical angina and recurrent tako - tsubo cardiomyopathy .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: department of justice ( doj ) guide has proposed to align scientific research about the risk of human immunodeficiency virus ( hiv ) transmission with best practices on when states should use hiv - specific laws to seek criminal charges and penalty enhancements . in particular \n , the doj report says that states may wish to retain criminal liability when a person who knows he / she is hiv - positive commits a ( non - hiv specific ) sex crime where there is a risk of transmission ( e.g. , rape or other sexual assault ) or when the individual knows he / she is hiv positive and the evidence clearly demonstrates that individual 's intent was to transmit the virus and that the behavior engaged in had a significant risk of transmission , whether or not transmission actually occurred , ( p. 4 ) . beyond these 2 circumstances \n , the best practices guide recommends that states reform and modernize laws to accurately reflect the underlying low risk of hiv transmission from biting , spitting , throwing body fluids , insertive / receptive oral intercourse , and antiretroviral therapy . yet , the infrequent application of hiv criminalization laws , the rise of mass incarceration in america , and penal policy changes in inmate hiv testing converge to raise 2 important questions about the sexual health and criminal demeanor of the hiv - positive community . \n first , recent work shows that growth in the criminal justice system has obscured national estimates of wages , employment , educational attainment , and political participation . as inmates are not included in household - based sample surveys , national statistics on major social indicators are distorted , with some estimates being biased by as much as 60% . \n it is possible that such sample selectivity among hiv - positive inmates induce similar statistical biases that inflate the overall prevalence and risk , belying the rationale for criminalization laws in states that rely on hiv prevalence rates from household surveys like the national health and nutrition examination survey ( nhanes ) . \n there is some evidence that including inmates in national estimates of hiv and tb makes little difference , but that finding is based on 1 wave of data that span 2 years . \n this study assesses bias over a 14 year period ( i.e. , 19992012 ) to investigate whether the population at risk of hiv exposure is contingent upon the inclusion of inmates . \n second , hiv criminalization laws emerged during the pre - art era when the potential for hiv transmission was very high . \n failure to disclose one 's hiv status placed romantic partners at risk for future infection , resulting in a sexual offense that increased the risk of morbidity and mortality because very few treatment options existed during the 1980s and early 1990s . furthermore , hiv legislation associated and codified into law specific violent and nonsexual acts that legislators inaccurately feared could transmit hiv ( biting , spitting , etc . ) . \n thus , many states criminalized the failure to disclose one 's hiv status as a sexual offence as well as violent behavior among individuals living with hiv , while other states enacted penalty enhancements for hiv - positive defendants during sentencing for other sexual offenses such as prostitution . in tennessee , for example , hiv exposure is specifically categorized as a violent offense that requires public sex offender registration for life . \n one supposition of hiv criminalization laws is that , by failing to disclose their infection , individuals who are infected seek to intentionally ( or negligently ) infect their partners and the population through sexual offenses and violent acts . yet \n research has not focused on how crimes committed by hiv - positive inmates differ from the overall crimes of other inmates . \n hiv criminalization laws rest partly on the assumption that the overall risk of transmitting the infection within the general population is high , regardless of treatment or safer sex practices . \n however , no research has assessed whether hiv - positive inmates are more or less likely to be jailed or imprisoned for violent offenses , in comparison to hiv - negative inmates . \n if hiv criminalization laws are meant to redress illegalities associated with sexually transmitting the infection without a partner 's knowledge or violence that threatens public health , the likelihood of serving sentences for violent acts should be greater among hiv - positive inmates ( compared to non - hiv inmates ) once the distribution of possible offenses ( violent , drug , property , etc . ) \n first , we assess measurement biases in hiv prevalence from national household - based surveys that do not include incarcerated population , which may be used to generate state - specific hiv prevalence rates in the absence of access to surveillance data . \n these household surveys can be used to set national and state social policy on corrections and population health . \n second , we show how statistical biases in household surveys undermine the conceptual basis for hiv criminal laws , particularly for states that draw on data from the noninstitutionalized population to make general claims that buttresses social policy \n . finally , we present a general criticism of the legal basis for hiv criminal laws that make assumptions about criminal intent and violent dispositions among individuals living with hiv / aids . \n in 2008 , 1 in 100 adults was behind bars , but over 64 million adults had some form of arrest or criminal conviction , representing 30% of the american adult population . by the close of 2012 , \n nearly 2.23 million men and women were incarcerated in local , state , and federal correctional facilities , and another 4.79 million were under some form of criminal justice supervision . \n exposure to the criminal justice system is not uniform ; race and class inequality in the likelihood of incarceration has grown over the last 40 years , with the life - time risk of imprisonment among young , undereducated african - american men hovering around 70% . \n incarceration is associated with an increased risk of infectious disease , stress , depression , unhealthy eating habits , body mass indexes ( bmi ) , and smoking , and recent work links incarceration to excess infant mortality in america and denmark . \n mass incarceration has such a profound impact on levels of social inequality in america that the health effects spill into and diffuse through communities , as male incarceration rates in the early 1980s through the mid-1990s are shown to be strongly associated with aids rates among men and women . during the rise of the aids epidemic , \n twenty - four states currently impose misdemeanor or felony penalties on hiv - positive people for engaging in a range of practices . \n most statutes criminalize sexual contact without first disclosing one 's hiv - positive status , regardless of whether that contact poses a risk of transmitting the virus ; others are widely construed to criminalize a range of potential exposures , even behaviors that are not plausible transmission pathways such as spitting and biting . \n in addition , a handful of other states impose sentence enhancements on hiv - positive defendants convicted of other sexual offenses such as rape or prostitution . in total \n although hiv was largely terminal without treatment during the pre - art era , the introduction of antiretrovirals in 1995 substantially increased survivorship . \n these treatments not only transformed the disease into a chronic , manageable illness , but also greatly reduced the infectiousness of those taking it . \n data recently announced from a trial involving virally suppressed partners in both heterosexual and same - sex serodiscordant relationships ( where one partner is hiv - positive and the other hiv - negative ) who were not using condoms at least some of the time reveal that , after an estimated 44,400 sexual encounters , zero transmissions were observed . although the science of hiv treatment and prevention has dramatically advanced in the 30 years since its discovery , the criminal laws governing those infected with hiv have remained largely static . the majority of hiv - specific criminal laws were enacted during the mid-1980s and early 1990s during a general panic about the disease and its potential to spread from minority communities to the general population . in this context , states enacted broadly construed laws that could be used to criminalize sexual contact without any risk of transmission . \n additionally , some policy debates have centered on highly aberrant cases involving male defendants ( often of color ) infecting multiple ( often white ) female partners . \n however , an analysis of convictions under michigan 's felony hiv disclosure statute between 1992 and 2010 reveals that less than 5% of convictions involved a defendant accused of transmitting the disease to a partner . the vast majority of cases involved a sexual exposure without transmission , some involving no or low risk sexual behaviors such as a 2009 case involving an hiv - positive michigan dancer accused of allowing a male client 's nose to penetrate her vagina during a lapdance . \n the criminal justice system is known to structure and recreate inequalities in health among inmates by selectively testing prisoners for hiv depending on state - specific laws and institutional facility type ( jail , state prison , etc . ) . \n for instance , although inmates are at a higher risk of contracting hiv / aids than the general population , state legislatures enact different guidelines about when and where to test inmates for this infection . in 2004 , 18 states had policies specifically aimed at testing all inmates for hiv at admission into prison / jail , while only 2 states had policies for testing inmates in custody , and 3 states tested prisoners upon release . \n nationally , the number of states that mandated hiv testing among inmates was greater around the dawn of the millennium than in subsequent years . between 2000 and 2004 \n , federal prisons ended testing all inmates and began testing groups they deemed to be high - risk . \n we assess the 2 critical suppositions of hiv criminalization laws : whether a prominent , national household survey routinely used to generate state - specific estimates of hiv overstates the level of prevalence in the population due to the exclusion of inmates ; and whether inmates with hiv are more or less violent than non - hiv infected inmates . \n nhanes data are collected by the national center for health statistics ( nchs ) , as part of the centers for disease control ( cdc ) . \n these data capture demographic , dietary , and health - related markers of a nationally representative sample of about 5000 residents each year . \n nhanes administers biennial laboratory tests for hiv antibodies to estimate the prevalence of hiv in the population . \n the age of the participants varied by survey wave , with the range going from 1849 in 1999 to 1859 in 2012 . to standardize across years , \n we limit the age range from 20 to 49 and apply survey weights to obtain nationally representative statistics by race . as the vast majority of inmates are male , we restrict our analysis to men \n . we also leverage data from the survey of inmates in state , federal , and local custody . \n data for the survey of inmates series are collected by the u.s . census bureau and \n the survey of inmates is nationally representative sample of all inmates held in correctional facilities throughout the united states . \n respondents include inmates being held pretrial , those serving local sentences , and those awaiting transfer into the custody of another correctional facility . \n the survey of inmates in state and federal correctional facilities was administered in 1997 and 2004 . \n data from the survey of inmates in local jails were collected in 1996 and 2002 . in each of these surveys , inmates were asked if they were ever tested for hiv and for the result of the test . to construct panel estimates of hiv prevalence among american inmates , we estimate the distribution of inmates who report being positive by race , weighted in proportion to aggregate penal population counts from bureau of justice statistics . estimates from between survey years \n are linearly interpolated , and postsurvey year prevalence is assumed to follow the weighted distribution of the most recent survey . \n this method has been used to construct time - series for parental incarceration , wage inequality , and the life - time risk of imprisonment . \n further details on our methodology and additional data used to produce these estimates can be found in other work . to make the analysis consistent with nhanes , we limit the sample to men age 20 to 49 . \n population denominators to calculate prevalence rates are obtained from 2 sources . when weighted , nhanes totals represent the noninstitutionalized population . \n another source of information about population counts come from the march current population survey ( cps ) . \n each month the cps samples approximately 50,000 to 60,000 americans living in households , and survey measures capture the demographic and labor market attributes of the noninstitutionalized population . \n census bureau and the bureau of labor statistics , and the cps has been fielded monthly since the 1940s . \n we compare hiv prevalence rates under each of these surveys to ensure that any bias in rates due to institutionalization are not due to population count differences between surveys . \n as this observational study relies on publicly available , secondary data sources that have been anonymized for widespread use , the risk to potential subjects is low . \n the data have been collected by government agencies tasked with anonymizing survey participants and ensuring minimal harm , and the data have been deidentified and can not be linked . as such \n , the institutional review board at the university of california - irvine classifies this research as exempt from review . \n nhanes data are collected by the national center for health statistics ( nchs ) , as part of the centers for disease control ( cdc ) . \n these data capture demographic , dietary , and health - related markers of a nationally representative sample of about 5000 residents each year . \n nhanes administers biennial laboratory tests for hiv antibodies to estimate the prevalence of hiv in the population . \n the age of the participants varied by survey wave , with the range going from 1849 in 1999 to 1859 in 2012 . to standardize across years , \n we limit the age range from 20 to 49 and apply survey weights to obtain nationally representative statistics by race . as the vast majority of inmates are male , we restrict our analysis to men \n . we also leverage data from the survey of inmates in state , federal , and local custody . \n data for the survey of inmates series are collected by the u.s . census bureau and \n the survey of inmates is nationally representative sample of all inmates held in correctional facilities throughout the united states . \n respondents include inmates being held pretrial , those serving local sentences , and those awaiting transfer into the custody of another correctional facility . \n the survey of inmates in state and federal correctional facilities was administered in 1997 and 2004 . \n data from the survey of inmates in local jails were collected in 1996 and 2002 . in each of these surveys , inmates were asked if they were ever tested for hiv and for the result of the test . to construct panel estimates of hiv prevalence among american inmates , we estimate the distribution of inmates who report being positive by race , weighted in proportion to aggregate penal population counts from bureau of justice statistics . estimates from between survey years \n are linearly interpolated , and postsurvey year prevalence is assumed to follow the weighted distribution of the most recent survey . \n this method has been used to construct time - series for parental incarceration , wage inequality , and the life - time risk of imprisonment . \n further details on our methodology and additional data used to produce these estimates can be found in other work . to make the analysis consistent with nhanes , we limit the sample to men age 20 to 49 . \n population denominators to calculate prevalence rates are obtained from 2 sources . when weighted , nhanes totals represent the noninstitutionalized population . \n another source of information about population counts come from the march current population survey ( cps ) . \n each month the cps samples approximately 50,000 to 60,000 americans living in households , and survey measures capture the demographic and labor market attributes of the noninstitutionalized population . \n census bureau and the bureau of labor statistics , and the cps has been fielded monthly since the 1940s . \n we compare hiv prevalence rates under each of these surveys to ensure that any bias in rates due to institutionalization are not due to population count differences between surveys . \n as this observational study relies on publicly available , secondary data sources that have been anonymized for widespread use , the risk to potential subjects is low . \n the data have been collected by government agencies tasked with anonymizing survey participants and ensuring minimal harm , and the data have been deidentified and can not be linked . as such \n , the institutional review board at the university of california - irvine classifies this research as exempt from review . \n table 1 displays the descriptive statistics for the survey of inmates and nhanes for the years that begin and end our survey . \n although subsequent analyses are only for men , this table is used to display the overall sample demographics . over 90% of all inmates \n are male , compared to almost half of respondents who had their blood tested by nhanes . \n although the overall modal ages are fairly similar for 1999 and 2012 among american inmates , the mean age among the nhanes sample increased over 5 years between 1999 and 2012 . descriptive statistics of the survey of inmates and the nhanes for select years , u.s . 1999 to 2012 similarly , the racial composition of the inmates in jails and prisons remained fairly stable , with roughly 65% of all inmates being non - hispanic whites . \n the nhanes sample shows relatively stable percentages among non - hispanic blacks and hispanics over the period , but the percentage of non - hispanic whites declines by almost 5 percentage - points , and the non - hispanic other group more than doubled in size . the educational disadvantage of american inmates has also increased overtime . in 1999 , roughly 41.4% of all men and women behind bars had less than a high school diploma ( i.e. , they dropped out of high school ) . by 2012 , \n shifts in the educational redistribution of inmates were largely at the expense of inmates who completed high school , as the percentage of inmates with a high school diploma dropped from 47.4% in 1999 to 35.4 in 2012 . \n respondents in the nhanes sample , on the other hand , experienced opposite movement in the redistribution of educational attainment . \n although individuals with low levels of education experienced some declines in representation between 1999 and 2012 , highly advantaged respondents became more prevalent by 2012 . \n college educated men and women , for example , increased their responsiveness by 9.2%-points , with 62.1% of nhanes respondents having some college education . \n the shifting educational distribution in these surveys raises important questions about whether hiv prevalence is concealed and distorted when institutions like the criminal justice system concentrate disadvantage and inmates remain outside sample selection eligibility for national surveys . \n indeed , some scholars have raised this concern for a number of clinical trial studies , where individuals unincarcerated in earlier waves of a study can not be followed at later times due to incapacitation and irb protocols around inmate research.table 1 shows that hiv prevalence among inmates increased from 2.8% in 1999 to 3.3% by 2012 . \n comparatively , lab work by nhanes shows that the percentage of americans who are hiv - positive declined , going from 1.1% in 1999 to 0.42% by 2012 . \n as inmates are disproportionately poor and possess low levels of education , resulting in their exclusion from national household - based surveys , a reexamination of hiv prevalence rates and bias due to their exclusion is warranted . \n currently , more than 1.2 million people are living with hiv . although national hiv prevalence estimates from the cdc are based on surveillance site statistics , national household - based surveys like nhanes are another source of data for states that seek to utilize social and epidemiological data on hiv prevalence within the population . \n the potential use of nhanes data to set social policy around state - specific hiv criminalization laws has yet to be investigated . to understand whether the rationale for hiv criminalization laws may be due to an overestimated risk of hiv spreading throughout the population due violent and deviant behavior \n , the number of americans living with hiv ( i.e. , the numerator ) must be standardized before adjusting the national prevalence rates for individuals living outside of households or in institutions . \n thus , cases reported to the cdc by its surveillance programs must be reconciled with national survey estimates from nhanes . \n table 2 shows the number of male adult or adolescent cases from 2008 to 2010 . \n even if the total population ( i.e. , the denominator ) included all persons in the united states , nhanes would overestimate hiv prevalence because the number of cases diverges from published cdc estimates in 2 of the 3 most recent years . \n for instance , nhanes hiv - positive cases are 2.8% and 10.6% greater than cdc estimates in 2008 and 2009 , respectively . only in 2010 \n does the number of hiv cases converge between nhanes and cdc estimates , with nhanes reporting 0.149% fewer infected individuals . \n number of male adult or adolescent hiv cases published by the cdc and estimated from nhanes , u.s . \n 2008 to 2010 prevalence estimates require information from household surveys on the noninstitutionalized to generate population counts . \n population counts from nhanes produce different hiv prevalence estimates than population counts from cps . similar to table 2 , where the incident counts differed for the numerator \n , the population counts for the denominator also induce sizeable differences in hiv prevalence rates . \n the population counts for the denominator ( i.e. , the population at risk of exposure ) can induce sizeable differences in hiv prevalence rates . \n we fix the numerator to be the number of hiv cases from nhanes and vary only the population denominators . \n if all members living in households have the same sampling probability across surveys , then hiv prevalence estimates between nhanes and the cps should not differ significantly . \n positive estimates indicate that prevalence rates are higher when using the nhanes population as the base , and negative estimates indicate that using population totals from the cps lowers the prevalence rate . \n for example , while nhanes and cps denominators made little difference in the total hiv prevalence rate for 1999 to 2001 , since 2002 , bias in population counts have diverged between the surveys . \n current estimates indicate that cps population totals produce a rate that is 7.8% lower than nhanes . \n race - specific hiv prevalence rates are particularly distorted , as nhanes overrepresented prevalence among non - hispanic blacks by 7.8% in 1999 . by 2012 , cps population totals lowered hiv prevalence by 19.3% compared to population counts from nhanes . prior to 2002 , \n note : positive estimates indicate that prevalence rates are higher when using the nhanes population as the base , whereas negative estimates indicate that using population totals from the cps lowers the prevalence rate by the corresponding percentage . \n cps = current population survey , nhanes = national health and nutrition examination study . \n as population counts are known to produce different estimates before including inmates , we average cps and nhanes population counts to limit the overall bias associated with choosing between surveys . \n we estimate bias in the hiv prevalence rate due to excluding inmates from household - based surveys in figure 2 . \n positive numbers indicate that current hiv prevalence rates should adjusted upward by the corresponding percentage to include inmates . \n negative numbers indicate that the inclusion of inmates lowered prevalence rates by the corresponding percentage . including inmates generally increases national hiv prevalence rates . yet , for non - hispanic blacks , inmate inclusion lowers national hiv prevalence for many of the years in our study . \n this finding is consistent with past research that examined 1 wave of nhanes data during the mid-2000s . \n source : authors calculations from the survey of inmates , the nhanes and the cps . \n note : positive numbers indicate that current national hiv prevalence rates should be adjusted upward by the corresponding percentage to include inmates . \n negative numbers indicate that the inclusion of inmates lowered prevalence rates by the corresponding percentage . \n cps = current population survey , hiv = human immunodeficiency virus , nhanes = national health and nutrition examination study . \n table 3 presents the distribution of controlling offenses ( or the most serious crime ) among inmates by race . \n hiv - positive inmates were incarcerated for violent offenses at rates substantially lower than other inmates . \n for example , in 1999 , 22.1% of all inmates were incarcerated for violent offenses compared to 14.5% of hiv - positive inmates , a 7.6%-point difference ( p < 0.001 ) . \n the rise in mass incarceration changed the overall offending composition by the end of our time series . by 2012 , \n the percentage of hiv - positive inmates incarcerated for violent offenses was lower than the overall population by 8.1 percentage - points ( p < 0.001 ) . \n the fraction of non - hispanic black men living with hiv who committed a violent offense was almost 15 percentage - points lower ( p < 0.001 ) than the overall population of black inmates . \n the distribution of controlling offenses among men 20 to 49 by race ( in percentages ) , u.s . \n 1999 to 2012 in table 4 , we fit probit models to estimate differences in the likelihood that hiv - positive inmates are more / less violent than hiv - negative inmates . \n we report marginal effects , which express the rate of change in the dependent variable ( i.e. , the predicted probability ) relative to a unit change in an independent variable . \n hiv - positive men were 10%-points less likely to have a violent offense than hiv - negative inmates . \n in fact , hiv - positive inmates are statistically more likely to be incarcerated for drug and property crimes ( 2.6% and 7.3% , respectively ) , not sexual or violent offenses . \n although drug and property crimes may increase the likelihood of experiencing violence , these findings indicate that hiv - positive inmates are significantly less violent than their counterparts . \n currently , more than 1.2 million people are living with hiv . although national hiv prevalence estimates from the cdc are based on surveillance site statistics , national household - based surveys like nhanes are another source of data for states that seek to utilize social and epidemiological data on hiv prevalence within the population . \n the potential use of nhanes data to set social policy around state - specific hiv criminalization laws has yet to be investigated . to understand whether the rationale for hiv criminalization laws may be due to an overestimated risk of hiv spreading throughout the population due violent and deviant behavior \n , the number of americans living with hiv ( i.e. , the numerator ) must be standardized before adjusting the national prevalence rates for individuals living outside of households or in institutions . \n thus , cases reported to the cdc by its surveillance programs must be reconciled with national survey estimates from nhanes . \n table 2 shows the number of male adult or adolescent cases from 2008 to 2010 . even if the total population ( i.e. , the denominator ) included all persons in the united states , nhanes would overestimate hiv prevalence because the number of cases diverges from published cdc estimates in 2 of the 3 most recent years . \n for instance , nhanes hiv - positive cases are 2.8% and 10.6% greater than cdc estimates in 2008 and 2009 , respectively . only in 2010 \n does the number of hiv cases converge between nhanes and cdc estimates , with nhanes reporting 0.149% fewer infected individuals . \n number of male adult or adolescent hiv cases published by the cdc and estimated from nhanes , u.s . \n 2008 to 2010 prevalence estimates require information from household surveys on the noninstitutionalized to generate population counts . \n similar to table 2 , where the incident counts differed for the numerator , the population counts for the denominator also induce sizeable differences in hiv prevalence rates \n . the population counts for the denominator ( i.e. , the population at risk of exposure ) can induce sizeable differences in hiv prevalence rates . \n we fix the numerator to be the number of hiv cases from nhanes and vary only the population denominators . \n if all members living in households have the same sampling probability across surveys , then hiv prevalence estimates between nhanes and the cps should not differ significantly . \n positive estimates indicate that prevalence rates are higher when using the nhanes population as the base , and negative estimates indicate that using population totals from the cps lowers the prevalence rate . \n for example , while nhanes and cps denominators made little difference in the total hiv prevalence rate for 1999 to 2001 , since 2002 , bias in population counts have diverged between the surveys . \n current estimates indicate that cps population totals produce a rate that is 7.8% lower than nhanes . \n race - specific hiv prevalence rates are particularly distorted , as nhanes overrepresented prevalence among non - hispanic blacks by 7.8% in 1999 . by 2012 , cps population totals lowered hiv prevalence by 19.3% compared to population counts from nhanes . prior to 2002 , \n note : positive estimates indicate that prevalence rates are higher when using the nhanes population as the base , whereas negative estimates indicate that using population totals from the cps lowers the prevalence rate by the corresponding percentage . \n cps = current population survey , nhanes = national health and nutrition examination study . \n as population counts are known to produce different estimates before including inmates , we average cps and nhanes population counts to limit the overall bias associated with choosing between surveys . \n we estimate bias in the hiv prevalence rate due to excluding inmates from household - based surveys in figure 2 . \n positive numbers indicate that current hiv prevalence rates should adjusted upward by the corresponding percentage to include inmates . \n negative numbers indicate that the inclusion of inmates lowered prevalence rates by the corresponding percentage . including inmates generally increases national hiv prevalence rates . yet , \n for non - hispanic blacks , inmate inclusion lowers national hiv prevalence for many of the years in our study . \n this finding is consistent with past research that examined 1 wave of nhanes data during the mid-2000s . \n source : authors calculations from the survey of inmates , the nhanes and the cps . \n note : positive numbers indicate that current national hiv prevalence rates should be adjusted upward by the corresponding percentage to include inmates . \n negative numbers indicate that the inclusion of inmates lowered prevalence rates by the corresponding percentage . \n cps = current population survey , hiv = human immunodeficiency virus , nhanes = national health and nutrition examination study . \n table 3 presents the distribution of controlling offenses ( or the most serious crime ) among inmates by race . \n hiv - positive inmates were incarcerated for violent offenses at rates substantially lower than other inmates . \n for example , in 1999 , 22.1% of all inmates were incarcerated for violent offenses compared to 14.5% of hiv - positive inmates , a 7.6%-point difference ( p < 0.001 ) . \n the rise in mass incarceration changed the overall offending composition by the end of our time series . by 2012 , \n the percentage of hiv - positive inmates incarcerated for violent offenses was lower than the overall population by 8.1 percentage - points ( p < 0.001 ) . \n the fraction of non - hispanic black men living with hiv who committed a violent offense was almost 15 percentage - points lower ( p < 0.001 ) than the overall population of black inmates . \n the distribution of controlling offenses among men 20 to 49 by race ( in percentages ) , u.s . \n 1999 to 2012 in table 4 , we fit probit models to estimate differences in the likelihood that hiv - positive inmates are more / less violent than hiv - negative inmates . \n we report marginal effects , which express the rate of change in the dependent variable ( i.e. , the predicted probability ) relative to a unit change in an independent variable . \n hiv - positive men were 10%-points less likely to have a violent offense than hiv - negative inmates . \n in fact , hiv - positive inmates are statistically more likely to be incarcerated for drug and property crimes ( 2.6% and 7.3% , respectively ) , not sexual or violent offenses . \n although drug and property crimes may increase the likelihood of experiencing violence , these findings indicate that hiv - positive inmates are significantly less violent than their counterparts . \n when hiv entered the national consciousness in the 1980s , hiv - positive people were quickly labeled as deviant by those holding homophobic views , increasing their willingness to believe myths of dangerousness . \n perceptions of hiv - infected persons as risky , dangerous , and threatening permeated public discourse to the point that a 1988 general social survey item revealed that 63.7% of americans were in favor of a government mandate that would require hiv - positive individuals to wear identification tags . \n the stigma associated with infection resulted in hiv criminalization laws that relied on national statistics about hiv prevalence among high risk groups , as well as misguided and biased assumptions about the criminal nature of hiv - positive men and women . \n recent studies suggest that hiv - specific criminal laws are not uniformly applied across the population . \n one study shows that hiv - positive heterosexual black men are more likely to have been convicted under the michigan nondisclosure law as compared to their white counterparts . \n contrary to expectations , however , hiv - positive gay men in the state were much less likely to have faced conviction as compared to their heterosexual counterparts . \n these findings echo those of other work , which shows that 80% of arrestees under tennessee 's hiv - specific criminal law , who were subsequently tried in nashville courts between 2000 and 2010 , involved men or women with opposite - gendered partners . \n findings from michigan and tennessee underscore how hiv criminalization laws may be differentially applied to segments of the population based on beliefs about the risk of transmission , disclosure , violent intentions , and institutional discrimination by race and sexual orientation . \n hiv criminalization laws promulgate myths of dangerousness through the presumption of individual duplicity between partners and collective misunderstandings about the overall risk to the population at large . \n distorted prevalence and incidence rates due to survey and sample bias contribute to such misconceptions by obscuring scientific facts about hiv transmission and the relative rate of violent offenses among those who are infected . \n our study finds that the population at risk of exposure is significantly overestimated and that hiv - positive inmates are significantly less likely to be incarcerated for violent offenses . \n hiv - specific laws compound the stigma associated with being hiv - positive , even if inmates are incarcerated for nonviolent and nonsexual crimes . \n an unintended consequence of this legislation is the further stigmatization of minority groups and communities , which may induce greater levels and varied forms of deviance as a result of increased ostracization and internalization of deviant labels . \n we show that the very premise of these criminalization laws are problematic in at least 2 respects . \n first , the correctional system incarcerates many individuals experiencing the most serious social problems in the country . \n prisons and jails concentrate disadvantaged men , most of whom have low levels of education and are disproportionately non - white . the rise of mass incarceration since the 1980s has come to obscure basic social facts about a host of population processes , including hiv prevalence rates overtime when estimated using household - based data . \n thus , health advocates and legislators should exercise caution when relying on nonsurveillance data from household surveys to devise state - specific social policy . \n second , hiv criminalization laws make explicit assumptions about the intentionality and negligence of those living with infections , particularly if they fail to disclose their hiv status . as a matter of fact \n , a number of men and women have been prosecuted even after disclosing their infection and in the absence of transmission , which serves to bolster claims about hiv stigma in the justice system . \n furthermore , past characterizations of hiv - positive individuals as dangerous and violent are not validated by data on offense classifications of inmates . \n hiv - positive inmates are statistically less violent than their counterparts and are more likely to be incarcerated for drug and property crimes . \n thus , hiv criminalization laws focused on sexual violations deliberately codify unfounded beliefs about who is at risk of exposure and the criminality of those who would seek to expose them . \n although public health institutions have been largely silent on hiv - specific criminal laws until very recently , a recent doj report calls for states to re - examine their hiv - specific criminal statutes and assess the laws in accordance with scientific understandings of transmission risk . \n however , evidence suggests that this critical stance toward hiv criminalization is not shared at all levels of the public health infrastructure . \n for example , one study found that local health officials in michigan had developed specific tools and strategies for catching hiv - positive clients suspected of nondisclosure . \n hiv criminalization laws impute a host of assumptions about the hiv - positive community and their sexual partners . \n these laws were created during an era of public fear and scientific mystery about the evolution , progression , and transmission of the disease . \n such legislation was enacted on speculation about the underlying risk of infection and the criminal intent of individuals living with hiv . \n over 30 years after the discovery of this disease , hiv laws represent a relic of our collective biases and misunderstandings that have since been compounded by the rise of mass incarceration and its corresponding distortion of national prevalence estimates . in the interest of public health and scientific validity \n , social scientists and legislators should reassess the evidence that purportedly undergirds characterizations of hiv - positive persons as dangerous liaisons with cruel intentions .", "role": "user" }, { "content": "abstracta 2014 u.s . \n department of justice best practices report advocates that states eliminate hiv - specific criminal penalties except under 2 conditions : when a human immunodeficiency virus ( hiv)-positive person intentionally commits a sex crime or transmits the virus by engaging in behavior that poses a significant risk of transmission , regardless of actual transmission . \n we assess the premise of these exceptions to understand whether these best practices are based on scientific evidence about the population at risk of infection and the risk of sexual violence by hiv - positive individuals.we employ nationally representative , cross - sectional survey data from the current population survey ( cps ) , the survey of inmates in state , federal , and local jails ( sisflj ) , and the national health and nutrition survey ( nhanes).data from the cps , sisflj , and nhanes are weighted and combined to analyze bias in the population at risk of hiv . \n linear probability models are employed to estimate the likelihood that hiv - positive inmates are incarcerated for violent or sexual offenses , net of socioeconomic factors.we find significant measurement bias in hiv prevalence rates . \n the selection of national surveys for population denominators distorts contemporary estimates of hiv prevalence by 7% to 20% . \n our findings also illustrate that hiv - positive inmates are 10 percentage - points less likely to be incarcerated for violent offenses than hiv - negative inmates.national best practice guidelines may undermine effective social policy that aims to curtail stigma within hiv - positive communities because scientific evidence neither include inmates into prevalence denominators ( as a measure of the population at risk ) nor assess the likelihood that hiv - positive inmates commit violent or sexual crimes .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: one - dimensional ( 1d ) semiconducting nanomaterials \n have proven their \n promising potential in crucial sensing applications by serving as \n chemical , biological , and light sensors . \n in particular , transparent conducting oxide \n ( tco ) nanostructures have shown their versatility in sensing various \n types of analytes ranging from gas species to biological molecules \n to light . \n the improved performance leading to increased signal and fast response \n time is often attributed to the inherently high surface - to - volume \n ratio of nanomaterials , when compared to the same sensing devices \n which are made from thin film or bulk structures . \n both individual \n nanostructures and their ensembles have been previously \n employed to construct sensor devices . \n typical fabrication processes \n involving individual nanostructures require the use of high - cost , \n low - yield , and highly specialized fabrication equipment , presenting \n challenges for scalability of their assembly and production . on the \n other hand , sensors constructed from networks of nanostructures \n are \n not subjected to the complicated fabrication processes often employed \n for single nanostructure devices , potentially enabling a large - scale \n production via facile and low - cost techniques . \n nanostructure network \n devices may also benefit from better light trapping and suppressed \n reflection . \n in addition to these advantages , ensemble \n platforms have shown to provide adequate or improved performances , making them very attractive , alternative sensor devices that are \n easy to fabricate . \n significant research efforts have so far been made \n to characterize single tco nanostructure devices . yet , it is equally \n important to examine nanomaterial network devices , when considering \n the aforementioned overall effectiveness of sensor devices constructed \n from nanomaterial ensembles . in this regard , \n we have previously demonstrated \n the different uses of indium tin oxide nanowire ( ito nw ) network systems \n in biomolecular fluorescence and surface - enhanced raman signal detection . \n we demonstrate that ito nw network - based devices can function as highly \n effective photodetectors capable of sensing ultraviolet ( uv ) and visible \n ( vis ) light with high sensitivity and fast response time . \n we also \n show that the uv / vis sensing capability of the ito nw mesh devices \n can be significantly improved by modifying the nws with a cationic \n polymer , poly - l - lysine . \n high photovoltage and photocurrent \n signals are observed from these sensors , with much faster rise and \n decay time than those reported for single nw devices . \n the photoresponsivity \n of the ito nw mesh devices is comparable to those of commercial uv / vis \n detectors even at a low bias . \n in addition , our ito nw mesh - based devices \n are fabricated with simple processes which do not involve lithographic \n patterning or thin film deposition \n . therefore , our approach can be \n highly beneficial to developing alternative platforms for low - cost , \n high performing photodetectors with improved scalability . \n silicon wafers ( resistivity < 1 cm , thickness : \n 0.017 \n in . ) and au colloid ( 20 nm in diameter ) were obtained from silicon \n quest international inc . \n a si wafer with a thin layer of au catalysts was \n then placed approximately 5 in . \n downstream from a 2:1 mixture of graphite \n and ito powder ( in2o3:sno2 = 90:10 \n wt % ) which was kept at the center of a home - built chemical vapor \n deposition ( cvd ) reactor . the sample was subsequently produced in \n the horizontal resistance furnace under a constant flow of 100 standard \n cubic centimeters per minute ( sccm ) of ar , similar to the process \n reported earlier at the reaction temperature \n of 850 c for 15 min . \n other nanostructures of tin oxide ( sno2 ) , zinc tin oxide ( zto ) , and zinc oxide ( zno ) were similarly \n produced for photovoltage comparison with ito . \n they were generated \n by using a 1:1 mixture of graphite and sno2 heated to 850 \n c for 2 h , a 5:1 mixture of graphite and zto powder ( sno2:zno = 50:50 wt % ) at 915 c for 10 min , and a 2:1 mixture \n of graphite and zno heated to 900 c for 1 h , respectively . \n the size and \n morphology of cvd - synthesized nanomaterials were then characterized \n by using a fei / philips xl 20 scanning electron microscope ( sem ) operated \n at 20 kv . \n x - ray diffraction ( xrd ) data were acquired by using a rigaku \n ultima iv x - ray diffractometer ( the woodlands , texas ) operated with \n an accelerating voltage and current of 45 kv and 44 ma , respectively , \n under cu k radiation . \n the samples were scanned at \n a rate of 2/min in the range of 2 = 580. ag contacts were fabricated using silver pastes ( ted pella , inc . ) \n on either end of the nanomaterial layer serving as the left ( l ) and \n right ( r ) electrodes for subsequent , lateral photovoltage ( lpv ) measurements . \n the sample assembly was then placed in a dark housing with a small \n front aperture to introduce a light source to the sample while eliminating \n any external optical and electrical noise . at the bottom center of \n the enclosure , \n a sample holder connects the two electrodes on the \n sample to the 200 mhz oscilloscope through a bnc connector for voltage \n characterization . a 543 nm hene laser ( newport corp . \n , santa clara , \n ca ) was used as a constant - wave , visible ( vis ) illumination source , \n with a spot diameter and laser power of 1 mm and 1.14 mw , respectively . \n newton , \n nj ) rotating with a predetermined frequency . uv illumination was delivered \n by a quanta - ray gcr-3 pulsed nd : yag laser ( spectra physics , santa \n clara , ca ) as a light source . \n the frequency - tripled output of the \n laser ( wavelength 355 nm ) has a measured pulse width of 8 ns , repetition \n rate of 10 hz , and maximum pulse energy of 200 mj . \n the beam was attenuated \n to give a pulse energy of roughly 15 j per pulse incident on \n the sample with a spot size of 1 mm . \n voltage \n ( i v ) measurements were carried \n out by sweeping the l \n r voltage using a hewlett - packard pa - meter / dc - voltage \n source , hp 4140b . \n figure 1(a ) displays representative 4 \n 4 m sem panels for as - grown sno2 , zto , zno , and \n ito nanomaterials . \n nanowire ( nw)-like structures are observed from \n sno2 and ito plates , whereas nanorod ( nr ) and nanobelt \n ( nb ) structures are found from the zno and zto plates , respectively . \n the average diameter of sno2 nws ( 35.7 2.0 nm ) is \n similar to that of ito nws ( 40 1.5 nm ) , whereas the diameter \n of zto nbs ( 333 45 nm ) is similar to that of zno nrs ( 300 \n 15 nm ) . \n figure 1(b ) shows a magnified sem panel \n and x - ray diffraction ( xrd ) data of ito nws , the material of focus \n in this paper . \n xrd peaks positioned at 30.45 , 35.28 , 50.80 , \n and 60.40 correspond to ( 222 ) , ( 400 ) , ( 440 ) , and ( 622 ) ito nw \n planes in the cubic crystal structure of bixbyite mn2o3 i type ( c - type rare - earth oxide structure ) , respectively . \n the atomic arrangements of in , sn , and o in the ito nws are depicted \n in the crystal structure model provided in figure 1(b ) . \n our overall experimental scheme for the nanomaterial \n network photoelectric measurements is displayed in figure 1(c ) . \n ( a ) 4 4 m sem images displaying typical \n cvd - grown \n structures of sno2 nws , zto nbs , zno nrs , and ito nws . \n ( b ) a 2 2 m , zoomed - in sem panel shows the structure \n of individual ito nws . \n xrd data of as - grown ito nws are also provided \n along with a schematic representation of the atomic arrangements in \n ito nw crystals . \n the device schematic \n provided in figure 2(a ) displays a typical \n sample configuration involving networks of \n ito nws . \n figure 2(a ) also displays a representative \n voltage response obtained from ito nws , showing a maximum photovoltage \n ( vph ) value of 31 mv . down ( up ) arrows \n inserted in figure 2 indicate the time when \n the 543 nm laser directed to the sample is on ( off ) through a 400 \n hz chopper wheel . in comparison , \n figure 2(b ) \n displays typical photovoltage plots acquired from the other three \n types of devices consisting of sno2 nws , zno nrs , and zto \n nbs . \n the voltage responses upon illumination on these materials are \n significantly lower than what we observe from ito nws . \n both zno nr \n and zto nb devices result in vph of 3 \n mv , whereas sno2 nws produce an even weaker signal of 2 \n mv . \n although the exact origin of the increased photovoltage response \n observed from ito nws in comparison to other nanomaterials is not \n clear yet , various inherent electrical properties of the materials , \n such as charge carrier density , resistivity , and carrier mobility , \n may contribute to this effect . \n the corresponding values for an ito \n thin film , for example , are , respectively , reported to be on the order \n of 5 10/cm , 2 10 cm , and 55 cm/(vs ) , whereas those of a zno thin film are 10 10/cm , 1 10 cm , and 35 \n cm/(vs ) . \n the higher \n charge carrier density and mobility combined with the lower resistivity \n of ito may promote the enhanced photoinduced voltage signal in our \n experiment . \n the magnitude of vph varies \n on the same sample devices depending on the laser position . \n the laser \n spot is kept on the sample location , producing the highest signal \n for all devices characterized in figure 2 . \n when comparing the highest vph of the \n different devices , the photoresponse of ito nws is an order of magnitude \n larger than other similar semiconducting oxide nanomaterials shown \n in figure 2(b ) . \n the response time of the \n photovoltage change of the ito nw device is determined by using the \n pulsed nd : yag laser as a light source . \n figure 2(c ) displays the typical response time of the ito nw photodetectors \n which is defined collectively by the rise ( tr ) and decay ( td ) time . \n the response \n time of ito nw devices is determined as tr = 20 s and td = 1.5 ms . \n ( a ) typical \n photovoltage acquired from ito nws while illuminating \n the device with a 543 nm laser through an optical chopper is shown . \n ( b ) photovoltage signal from sno2 , zto , and zno nanostructures \n is recorded when using the same light source as ( a ) . \n ( c ) typical photovoltage \n signal obtained from ito nw devices when using a 355 nm pulsed laser \n is provided . \n the inset is a zoomed - in view with the light on to show \n clearly the rise time . \n electrical responses in many nanomaterial - based electronic \n devices \n can be effectively tailored by a simple modification of the channel \n surfaces of the devices . \n organic amines and polymers have been utilized previously as gates \n or gate modifiers in chemical- and electrolyte - gating applications , \n respectively . \n these methods can produce a large change in electrical signal via \n simple means without introducing chemical dopants or charge - separating \n layers into the channel material . in order to test whether the light - activated , \n electrical response of our nanomaterial devices can be altered in \n a similar way , a cationic polymer of pll was chosen as a model system \n and uniformly applied to the surface of the ito nw layer . \n typical \n photovoltage signals from the pll - treated ito nw ( pll / ito nw ) devices \n were subsequently probed by using the 543 nm laser , and the results \n are provided in figure 3(a ) . when keeping the \n same laser spot on the sample position yielding the highest signal , \n a significantly increased vph value of \n 100 mv is recorded on pll / ito nws as plotted in black in figure 3(a ) . \n the photoresponse decreases when it is positioned \n away from the edge toward the middle of the sample . \n colored plots \n in figure 3(b ) display such changes in photoresponse \n amplitudes when varying the laser position along a line spanning from \n one electrode to the other ( marked as l and r electrodes in the schematics ) \n on the pll / ito nw device . \n vph varies with \n the light position on the line between the l and r electrodes with \n vph/x of \n approximately 20 mv / mm for pll / ito nws . \n figure 3(c ) displays the photovoltage response of the pll / ito nw device upon \n illumination with the 355 nm pulsed laser . \n the response time of the \n pll / ito nw device is slightly longer than the ito nw device , exhibiting tr = 30 s and td = 3.7 ms . \n ( a ) typical photovoltage response obtained \n from pll - modified ito \n nw devices upon periodic illumination with a 543 nm laser displayed . \n plots indicated as ( 1 ) , ( 2 ) , and ( 3 ) correspond to voltage signal \n changes depending on the laser position as indicated in the schematic . \n ( b ) voltage difference ( vph \n vd ) between 543 nm light - on and -off is recorded \n at five different illumination positions along the middle of the pll / ito \n nw device spanning one electrode to the other . \n relative laser positions \n are marked as ( 1 ) through ( 5 ) as shown in the schematic . \n ( c ) typical \n photovoltage signal obtained from pll / ito nw devices probed by a 355 \n nm pulsed laser is shown . \n the inset is a zoomed - in view with the light \n on to show clearly the rise time . \n as the excitation wavelengths of both lasers used in our \n experiments \n are below the bandgap of ito nws ( > 3.75 \n ev ) , the photoresponse is not due to the generation of charge carriers \n from bandgap transition . \n one possible cause for the photovoltage is \n local heating in the region of the ito nw network irradiated by the \n laser . \n it is known that light - induced temperature gradients in single \n and ensemble nanomaterials can produce a photovoltage through photothermoelectric \n effect ( pte ) in a carbon nanotube , graphene , mos2 , and \n gaas nw devices . upon illumination \n , there will be a net electrical current from the \n hot side to the cold side until the electric field build - up balances \n this current . \n when the laser spot is positioned on one side of the \n network , close to one contact , the photovoltage is highest since the \n net current from the one contact ( on the hot side ) to the other contact \n ( on the cold side ) will be largest . when the laser spot is moved close \n to the middle of the sample , the current caused by the temperature \n gradient will flow from the hot middle region in both directions toward \n the two colder contacts , yielding a smaller net photovoltage . \n therefore , \n for a symmetric device , photovoltage should be zero when the laser \n is positioned in the middle . \n our results shown in figure 3(b ) indicate an asymmetric device behavior , yielding \n a nonzero photovoltage at all five laser positions tested . in \n order to understand this response , current voltage ( i v ) \n r voltage from 3 to 3 v with an increment \n of 10 mv using the hp pa - meter / dc - voltage source . \n the light source \n used for the i v measurements was the 543 \n nm laser . \n figure 4 displays the resulting i v characteristics of the ito nw devices with and \n without the pll modification . \n asymmetric i v curves are observed from both ito nw and pll / ito nw devices . \n such \n asymmetrical i v curves have been reported \n previously on single nanomaterial devices such as zno nbs and nws \n as well as ge nw mesh devices . \n however , the exact origin of the rectifying i v curves in these systems is not clear and still \n under debate . \n ( a ) typical current versus voltage ( i v ) plot is shown for ito nws . \n dark current ( i d ) and photocurrent ( iph ) are obtained \n while sweeping the l \n r voltage from 3 to + 3 v. the \n 543 nm laser serves as the illumination source . \n v plot in the right panel displays a magnified view of the blue squared \n region in the i v curve on the left . the open - circuit \n voltage ( voc ) and short - circuit current \n ( isc ) upon illumination are determined \n as 15 mv and 7.7 10 a , respectively , for \n the ito nws . \n ( b ) typical i v characteristics \n are displayed for pll / ito nw devices . \n the open - circuit voltage ( voc ) and short - circuit current ( isc ) upon illumination are determined as 67 mv and 1.0 \n 10 a , respectively , as indicated in the \n magnified i v panel shown on the right . \n ( c ) \n the photoresponsivity data of the ito nw and pll / ito nw mesh devices \n are plotted against the bias in black and purple , respectively . \n surface charge- and oxygen adsorbate - driven \n mechanisms often explaining \n photocurrent transport behaviors of many single nw devices will lead \n to a much slower reset time than what we observe from ito nw - based \n devices . \n this slow response time of single nw devices is due to a \n long time scale associated with surface trap charging and the oxygen \n readsorption process ( several minutes to hours ) . \n in contrast , the very fast response and decay time observed from \n our ito nw network devices in figures 2(c ) \n and 3(c ) strongly suggest that a different \n mechanism may play a key role in our nw mesh configuration . \n we hypothesize \n that our devices are governed by a barrier - dominated transport mechanism . \n the l and r electrodes in our devices form different contact barriers \n at the interface with the ito nw network due to variations in contact \n conditions caused by nonuniformity of the network , yielding asymmetric i v characteristics . at the same time , nw nw \n junction barriers existing in the nw mesh configuration may also contribute \n to the asymmetry of the i v curves . \n the typical \n rise / decay time , on the order of micro-/milliseconds , observed from \n our ito nw network devices indicates that photothermally induced charge \n carriers are instantaneously formed within tens of microseconds after \n illumination with the pulsed laser . \n however , such charge carriers \n can be restrained at the nw nw interfaces and/or nw \n ag \n contact junctions , resulting in decay times in tens of milliseconds \n when the light is off . \n hence , an alternative ito device fabricated \n with aligned nws between the two contacts may be able to reduce the \n time scale gap between the rise and decay time by minimizing the carrier \n trap at the nw nw interfaces . \n further work is underway to measure \n exactly the differences in the contact barriers at the nw \n metal \n junctions in the l and r electrodes as well as to investigate the \n choice of metal for the electrodes . \n the open circuit voltage \n ( voc ) and \n short circuit current ( isc ) were also \n obtained from the i v curves . \n these results \n are clearly seen in the zoomed - in i v plots \n of figures 4(a ) and 4(b ) for the ito nw and pll / ito nw device , respectively . under the \n dark condition , no significant voc or isc \n is measured from the ito nw or the pll / ito \n nw device . upon illumination , \n the ito nw device exhibits voc and isc of 15 mv and 7.7 \n 10 a , respectively . \n these values change \n to voc = 67 mv and isc = 1.0 10 a for the pll - modified \n ito nw device under the same illumination condition . \n figure 4(c ) displays the photoresponsivity , r = [ ( iph id)/(p*a ) ] , of the ito nw \n and pll / ito nw devices shown in figures 4(a ) \n and 4(b ) . \n iph , i d , p , and a correspond to the photocurrent , dark current , power density of the \n laser , and the cross - sectional area of the illumination , respectively . \n when using the 543 nm laser , the ito nws reach the r value of 0.07 a / w at 3 v , whereas the pll - treated ito nws display r = 0.2 a / w at the same bias . \n the typical photoresponsivity \n of most commercial uv and vis photodetectors is in the range of 0.10.2 \n and 0.10.5 a / w , respectively . \n hence , the photoresponsivity \n of our ito nw mesh - based devices is comparable to the performance \n of commercial uv and vis photodetectors . \n for comparison with \n other similar nanomaterial devices , table 1 lists the performance characteristics of uv and \n vis photodetectors made from various individual and ensemble tco nanomaterials . \n key parameters of the light sensors are also shown along with those \n of our ito nw mesh - based devices . the high performing ito nw mesh \n devices demonstrated in this study \n can be straightforwardly constructed \n without the use of intensive lithographic steps and , thus , can potentially \n enable a large - scale production of ito nw - based , uv vis photodetectors . \n at the same time , our ito nw network devices display fairly high iph and r values even at a low \n bias of 3 v , while featuring a very fast response time of tr and td . \n co - zno nb and sno2 nb \n devices contain ensembles of nanomaterials , whereas zno nw and \n in2o3 nw systems are examples of individual \n nanomaterial devices . \n parameters such as bias voltage ( v ) , photocurrent ( iph ) , rise time ( tr ) , and decay time ( td ) are catalogued . \n in summary , we have shown that ito nws and pll / ito nws configured \n in a network format can be effectively used as high performing uv / vis \n photodetectors . \n the photovoltage response of ito nws is much higher \n than similarly constructed devices made from sno2 nws , \n zto nbs , and zno nrs . \n the ito nw mesh - based devices yield substantial \n photovoltage and photocurrent values of 31100 mv and 225325 \n a at 3 v , respectively , under illumination with a 1.14 mw , \n 543 nm laser . \n the photoresponsivity of the ito nw devices ranges from \n 0.07 to 0.2 a / w at a 3 v bias . \n the response time of the devices exhibits \n a rise time of 2030 s and a decay time of 1.53.7 \n ms when probed with a 355 nm pulsed laser . \n these photodetectors are \n simple and straightforward to construct without the need of complicated \n fabrication steps involving highly specialized instrumentations . \n therefore , \n our efforts demonstrate that ito nw network - based photodetectors can \n serve as a convenient alternative to commercial or single nw - based \n devices as easily assembled , high performing photodetectors .", "role": "user" }, { "content": "we \n demonstrate that indium tin oxide nanowires ( ito nws ) and cationic \n polymer - modified ito nws configured in a network format can be used \n as high performing uv / vis photodetectors . \n the photovoltage response \n of ito nws is much higher than similarly constructed devices made \n from tin oxide , zinc tin oxide , and zinc oxide nanostructures . \n the \n ito nw mesh - based devices exhibit a substantial photovoltage ( 31100 \n mv under illumination with a 1.14 mw 543 nm laser ) and photocurrent \n ( 225325 a at 3 v ) . \n the response time of the devices \n is fast with a rise time of 2030 s and a decay time \n of 1.53.7 ms when probed with a 355 nm pulsed laser . \n the photoresponsivity \n of the ito nw devices ranges from 0.07 to 0.2 a / w at a 3 v bias , whose \n values are in the performance range of most commercial uv / vis photodetectors . \n such useful photodetector characteristics from our ito nw mesh devices \n are attained straightforwardly without the need for complicated fabrication \n procedures involving highly specialized lithographic tools . \n therefore , \n our approach of ito nw network - based photodetectors can serve as a \n convenient alternative to commercial or single nw - based devices .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: human parvovirus b19 ( hpv - b19 ) infection is generally encountered in 4- to 10-year - old children.1 aside from asymptomatic mild flu - like symptoms , most children present with typical symptoms of erythema infectiosum ( slapped - cheek rash ) because the primary targets are erythroid progenitor cells . because the temporary bone marrow infection causes transient erythropoiesis arrest,2 this infection is particularly problematic for patients with hematological disorders , such as chronic hemolytic anemia , which includes sickle cell disease , hereditary spherocytosis , and infection with human immunodeficiency virus ( hiv).1 during hpv - b19 infection \n , these patients fail to increase erythroid progenitor cell formation to compensate for red blood cell lysis , leading to acute erythroblastopenia ( aplastic crisis ) . \n therefore , it is important to diagnose all cases of hpv - b19 , even if the infection generally subsides without medication , in case the patient has an undiagnosed hematological disorder . \n immunity prevalence for hpv - b19 increases with age and exceeds 60% in adults.3 however , cases of infection have been reported in adults , most of which present milder erythema infectiosum , arthralgia , and purpuric papular eruptions on hands and feet ( gloves and socks syndrome).1 we encountered three cases of hpv - b19 in adult patients presenting with unusual symptoms , such as leukopenia and low platelet counts . \n the patient was a 40-year - old female office worker with no children . there was no indication of cytopenia in past health examinations . \n on 16 january 2011 , the patient developed a fever of 39 c , systemic pain , fatigue , and loss of appetite . \n because the symptoms persisted , the patient was readmitted to our hospital on 19 january 2011 . \n leukopenia ( 1,000/l ) and low platelet counts ( 15 10/l ) were observed ( table 1 ) . \n the patient tested negative for hiv-1 and hiv-2 antibodies , and her hpv - b19 immunoglobulin m ( igm ) antibody titer was 2.64 . in all , 14 days later , the patient showed a leukocyte count of 2,800/l and a platelet count of 34.74 10/l , which were indicative of recovery . \n the patient was a 36-year - old housewife , with children aged 2 and 7 years , who were not suffering from erythema infectiosum . \n starting on 5 august 2010 , the patient experienced general fatigue and a mild fever of 38 c . \n on 9 august 2010 , the fever progressed to 39 c , and the patient noticed erythema on her extremities and trunk . \n therefore , she was admitted after examination to our internal medicine outpatient department on 10 august 2010 . \n she had no lymphadenopathy on admission but had lacy erythematous rashes on her trunk and bilateral upper extremities and thighs . \n leukopenia ( 2,000/l ) and low platelet counts ( 8.9 10/l ) were observed ( table 1 ) . \n the patient tested negative for hiv-1 and hiv-2 antibodies , and her hpv - b19 igm antibody titer was 11.63 . in all , 14 days later , the patient showed a leukocyte count of 3,600/l and a platelet count of 25.7 10/l , which were indicative of recovery . \n the patient was a 31-year - old female office worker ( number of children not disclosed ) . \n starting on 12 december 2010 , the patient experienced flu - like symptoms of pharyngodynia and fatigue . \n therefore , she was admitted following examination to our internal medicine outpatient department on 15 december 2010 . \n her body temperature was 38.2 c , and there were rashes on her trunk and extremities . \n leukopenia ( 1,400/l ) and low platelet counts ( 10.6 10/l ) were observed ( table 1 ) . \n the patient tested negative for hiv-1 and hiv-2 antibodies , and her hpv - b19 igm antibody titer was 2.24 . in all , 14 days later , the patient showed a leukocyte count of 4,300/l and a platelet count of 23.8 10/l , which were indicative of recovery . \n the fact that three cases were observed over the stated time period at our hospital , which is located in nagoya city , was indicative of a transition to a slightly higher level of incidence than the annual average ( fig . 1 ; according to documents from port of nagoya s public health center ) . \n the patient was a 40-year - old female office worker with no children . there was no indication of cytopenia in past health examinations . \n on 16 january 2011 , the patient developed a fever of 39 c , systemic pain , fatigue , and loss of appetite . \n because the symptoms persisted , the patient was readmitted to our hospital on 19 january 2011 . \n leukopenia ( 1,000/l ) and low platelet counts ( 15 10/l ) were observed ( table 1 ) . \n the patient tested negative for hiv-1 and hiv-2 antibodies , and her hpv - b19 immunoglobulin m ( igm ) antibody titer was 2.64 . in all , 14 days later , the patient showed a leukocyte count of 2,800/l and a platelet count of 34.74 10/l , which were indicative of recovery . \n the patient was a 36-year - old housewife , with children aged 2 and 7 years , who were not suffering from erythema infectiosum . there was no indication of cytopenia in past health examinations . \n starting on 5 august 2010 , the patient experienced general fatigue and a mild fever of 38 c . \n on 9 august 2010 , the fever progressed to 39 c , and the patient noticed erythema on her extremities and trunk . \n therefore , she was admitted after examination to our internal medicine outpatient department on 10 august 2010 . \n she had no lymphadenopathy on admission but had lacy erythematous rashes on her trunk and bilateral upper extremities and thighs . \n leukopenia ( 2,000/l ) and low platelet counts ( 8.9 10/l ) were observed ( table 1 ) . \n the patient tested negative for hiv-1 and hiv-2 antibodies , and her hpv - b19 igm antibody titer was 11.63 . \n in all , 14 days later , the patient showed a leukocyte count of 3,600/l and a platelet count of 25.7 10/l , which were indicative of recovery . \n the patient was a 31-year - old female office worker ( number of children not disclosed ) . \n starting on 12 december 2010 , the patient experienced flu - like symptoms of pharyngodynia and fatigue . \n therefore , she was admitted following examination to our internal medicine outpatient department on 15 december 2010 . \n her body temperature was 38.2 c , and there were rashes on her trunk and extremities . \n leukopenia ( 1,400/l ) and low platelet counts ( 10.6 10/l ) were observed ( table 1 ) . \n the patient tested negative for hiv-1 and hiv-2 antibodies , and her hpv - b19 igm antibody titer was 2.24 . in all , 14 days later , the patient showed a leukocyte count of 4,300/l and a platelet count of 23.8 10/l , which were indicative of recovery . \n the fact that three cases were observed over the stated time period at our hospital , which is located in nagoya city , was indicative of a transition to a slightly higher level of incidence than the annual average ( fig . 1 ; according to documents from port of nagoya s public health center ) . \n we encountered three cases of acute hpv - b19 infection in adult females for which a definitive diagnosis is made by confirming the presence of hpv - b19 igm antibodies or an increase in igg antibody titer paired serum . in these cases , an increase in hpv - igm antibodies was observed in blood tests upon admission . \n hayakawa et al.4 reported the clinical findings of 21 consecutive patients with adult hpv - b19 infection . in that report \n , the predominant signs and symptoms were fever exceeding 38.3 c ( 81% ) , skin rash ( 47.6% ) , arthralgia / myalgia ( 61.9% ) , general fatigue ( 42.9% ) , lymph node swelling ( 38.1% ) , edema ( 38.1% ) , and petechiae ( 14.3% ) . in our cases , \n the predominant signs and symptoms were fever exceeding 38.2 c ( 100% ) , general fatigue ( 100% ) , skin rash ( 66.6% ) , and arthralgia / myalgia ( 33.3% ) . \n they also exhibited concomitant leukopenia and low platelet counts . because hematopoietic disease could not be excluded , bone marrow aspiration was conducted in one case , but no obvious hematopoietic dysfunction profile was observed . \n cases of acute hpv - b19 infection exhibiting leukopenia and low platelet counts have been reported sporadically over the past 15 years.511 although there are various theories regarding the cause , nothing has been specified \n . there are reports of a connection with hemophagocytic syndrome accompanying infection,1215 but bone marrow examinations did not reveal a hemophagocytic profile in any one of our three cases , and the involvement of hemophagocytic syndrome could be excluded based on their clinical courses . \n furthermore , b19 receptors are believed to be erythrocyte - like p antigens,1618 which lead to anemia in patients with a background of accelerated erythropoiesis ( eg , hemolytic diseases ) . \n precursor cells outside the hematopoietic stem cell erythroid lines can also be infected , and some are of the opinion that this causes leukopenia.19 however , bone marrow is not necessarily hypoplastic in cases with b19-induced neutropenia , and in bone marrow examinations in case 3 , no hypoplasia was observed . \n sakai et al.20 suggested that neutropenia caused by b19 is not because of the direct effect of the virus but rather because of secondary leukocyte elimination and consumption . \n in addition , there are reports that anti - neutrophil antibodies are commonly detected in chronic neutropenia in infant b19 infections.21 it is also suggested that the mechanism of b19-induced leukopenia and low platelet counts may be different from that of anemia . \n furthermore , although it is unknown whether there was a decrease in serum granulocyte colony - stimulating factor ( g - csf ) as quantification of serum g - csf was not conducted in any of our three cases , none of the cases required g - csf administration . \n there are reports of g - csf administration,5 but administration is considered unnecessary in the absence of serious life - threatening complications such as septicemia . as the other complications , \n hpv - b19 has been reported in association with a wide range of diseases and clinical manifestations , including arthritis , vasculitis , myocarditis , nephritis , lymphadenitis , immune thrombocytopenia ( itp ) , meningitis and encephalitis , hemophagocytic syndrome , fulminant liver disease , and generalized edema , as well as many other conditions.22 also , the observation that many cases of chronic fatigue syndrome ( cfs ) begin with a flu - like illness prompted the hypothesis that viral infections were implicated in the disease , and several viruses were suggested as etiological agents for cfs . \n hpv - b19 has been reported to be one of these viruses.23,24 in conclusion , we encountered three adults who were diagnosed with acute hpv - b19 infection after the simultaneous observation of acute flu - like symptoms , leukopenia , and low platelet counts . \n this case series emphasizes that the epidemic period should also be considered and hpv - b19 infection should be actively suspected in adult patients with hematocytopenia even if typical clinical findings ( ie , skin rash ) are absent .", "role": "user" }, { "content": "we encountered three adult patients with flu - like symptoms diagnosed with human parvovirus b19 ( hpv - b19 ) infection . \n blood serum analysis also revealed leukopenia , with white blood cell counts ( wbcs ) of 1,0002,000/ml and low platelet counts of 89150 109/l . \n typical skin rash was absent in one patient . \n bone marrow examination of another patient showed hypoplastic marrow with < 5% blast cells . \n all patients recovered without administration of granulocyte colony - stimulating factor ( g - csf ) . \n therefore , hpv - b19 infection with leukopenia should be considered in adult patients with leukopenia during erythema infectiosum epidemics , even if typical clinical findings ( ie , skin rash ) are absent . \n further , the fact that three cases were observed over the stated time period at our hospital , which is located in nagoya city , showed a transition to a slightly higher level of incidence than the annual average .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: aortic valve stenosis is a quite frequent valvular disease which could require surgical treatment [ 1 , 2 ] . \n aortic valve replacement by open chest surgery is still considered the gold standard for symptomatic patients , but recently transcatheter aortic valve implantation ( tavi ) has become an option for patients at high surgical risk . for one third of these patients , \n not accepted for surgical treatment due to advanced age , comorbidities , and high surgical risk , medical evidence suggests that tavi is feasible and provides a hemodynamic and clinical improvement up to two years , even if long - term durability is still debated . \n aortic stenosis causes increased left ventricular ( lv ) afterload , which leads to lv hypertrophy and remodeling towards heart failure , increased morbidity and mortality . \n surgical treatment , on the one hand , has already been demonstrated to reduce lv mass and improve systolic and diastolic lv parameters , thus prolonging survival . \n tavi , on the other , seems to improve diastolic function and to favor left ventricular mass regression ( lvmr ) after six months . \n the impact of the procedure on lv systolic parameters like peak longitudinal strain have not yet been extensively evaluated . \n the aim of the present study was to assess lvmr and peak longitudinal strain improvement six months after tavi compared to pre - procedural assessments . \n moreover , we wanted to investigate whether longitudinal strain parameters before the procedure could predict lvmr . \n subjects . from january 2011 to august 2011 we consecutively enrolled 23 patients with pure symptomatic severe aortic stenosis and left ventricular ejection fraction > 45% who underwent successful tavi at the cardiologic unit of university civil hospital of brescia , italy . \n exclusion criteria were : history of ischemic heart disease , high blood pressure , hypertensive cardiomyopathy , dilated cardiomyopathy , and congenital heart defects . \n patients were treated with tavi if the aortic valve area was 2 , if the european system for cardiac operative risk evaluation score ( euroscore ; supplementary data online , appendix s1 ) was > 20% or if one or more of the following criteria was met : contraindication for surgery , severely reduced pulmonary function , liver cirrhosis , or metastatic cancer . \n all patients underwent the tavi procedure with a third - generation self - expanding corevalve prosthesis ( medtronic , minneapolis , mn ) . \n the procedure was performed at the catheterization laboratory under local anesthesia and mild sedation with fluoroscopy guidance . \n procedural success was defined as implantation of a functioning aortic prosthesis valve without intraprocedural mortality and with a paravalvular leak < 2 . \n we state that our study complies with the declaration of helsinki and that all patients gave their informed written consent to access their data for scientific purposes . \n the arm in which the highest sitting diastolic pressures were found was the arm used for all subsequent readings throughout the study . \n every effort was made to have the same staff member obtain blood pressure measurements in each individual patient , at the same time of day , using the same equipment . \n systolic pressure was recorded when the initial sound was heard ( phase i of the korotkoff sound ) , while diastolic pressure was recorded at the disappearance of the sound ( phase v of the korotkoff sound ) . \n echocardiograms were done using vivid 7 ( general electric medical systems , milwaukee , wi , usa ) equipment using a 3.5 mhz transducer , with the patients in the left lateral decubitus position , in accordance with the standardization of the american society of echocardiography . \n digital loops were stored on the hard disk of the echocardiograph for on - line and off - line analyses and transferred to a workstation ( echopac ; ge health - care , waukesha , wi , usa ) for off - line analysis . \n the echocardiographic measurements of the left ventricular end - diastolic diameter ( lvedd ) , interventricular septal thicknes ( ivst ) , and posterior wall thickness ( pwt ) were performed off - line according to recommendations of the american society of echocardiography . left ventricular volume and ejection fraction were obtained by the modified biplane simpson method . \n lv mass was calculated according to the formula : 0.8 x [ 1.04 x ( lvedd + pwt + ivst)3 - lvedd3 ] + 0.6 ( g ) , and indexed for body surface area . \n lvmr was defined as the difference between lv mass index for body surface area after six months and before the procedure . \n end - diastolic relative wall thickness was the ratio of 2 x pwt / lvedd . \n aortic valve area was calculated by the continuity equation , and the maximum pressure gradient across the restrictive orifice was estimated by the modified bernoulli equation . \n mean transaortic pressure gradient was calculated by averaging the instantaneous gradients over the ejection period on the continuous - wave doppler recordings . \n the assessment of longitudinal peak systolic strain was performed offline to the apical two - chamber , four - chamber , and long - axis views of the left ventricle . in brief , the endocardial contour was manually traced at an end - systolic frame . \n the software then automatically traced a concentric region of interest including the entire myocardial wall . \n strain analysis was performed by dividing each lv image into six segments per view . with the beginning of the qrs complex and the aortic valve closure time as reference points , \n systolic global longitudinal strain was calculated by averaging the peak systolic values of the 18 segments [ 20 , 21 ] . \n all analyses were carried out using ibm spss statistics 20 for windows ( spss , inc . , \n continuous variables were tested for normality with the kolmogorov - smirnov test and are represented by mean standard deviation , while categorical variables are represented as frequency ( n ) and percentage of the sample . \n paired - samples student s t - test and wilcoxon signed rank test were performed to analyze the difference between means for continuous variables between baseline and 6-month follow - up , and 2 test was performed to assess the difference between proportions for categorical variables ( fisher s exact test if dichotomic ) . \n bivariate spearman s correlation and linear regression were run between lv strain parameters at baseline and lvmr to investigate their predictive value . \n mean age was 838 years , ten patients were male ( 43.5% ) and the logistic euroscore was 24.915.1% . \n one patient was in new york heart association ( nyha ) class i ( 4.3% ) , seven in nyha class ii ( 30.5% ) and 15 in nyha class iii ( 65.2% ) . \n the peak and mean baseline transvalvular gradients were 8821 mmhg and 5616 mmhg , respectively . \n calculated aortic valve area index at baseline was 0.330.15 cm / m . at six months of follow - up nyha class \n improved with ten patients in nyha class i ( 43.5% ) , 12 in nyha class ii ( 52.2% ) , and three in nyha class iii ( 4.3% ) ( p<0.001 ) ( table 2 ) , while systolic blood pressure increased from 1159 to 1228 ( p=0.024 ) and diastolic pressure from 786 to 836 ( p=0.031 ) . \n lv = left ventricular ; ivst = interventricular septal thicknes ; pwt = posterior wall thickness ; lvedd = left ventrhicular end - diastolic diameter . \n a complete study data set was available for all patients : the echocardiographic parameters evaluated at baseline and during follow - up of six months are summarized in table 2 and figure 1 . \n there were significant periprocedural reductions in peak ( to 177 mmhg ; p<0.001 ) and mean ( to 105 mmhg ; p=0.005 ) transvalvular gradients . \n lv ejection fraction improved from 566% to 5811% without reaching statistical significance ( p=0.626 ) , as well as lvedd index ( p=0.079 ) . \n vice versa , ivst and pwt significantly decreased in six months ( p < 0.001 for both ) . \n the distribution of the lvmr grade is shown in figure 2 . left ventricular mass regression six months after tavi . \n there were no gender - related differences in lvmr , being -2716% in males and -2012% in females ( p=0.376 ) . \n bivariate correlations between lvmr and lv longitudinal strain parameters at baseline are shown in table 3 and figure 3 , while linear regression in table 4 . \n scatter plots of lvmr and lv longitudinal strain parameters at baseline ( a = peak longitudinal strain 2 chambers ; b = peak longitudinal strain 3 chambers ; c = peak longitudinal strain 4 chambers ; d = global longitudinal strain ) . \n lv hypertrophy in aortic stenosis is an adaptive mechanism to ensure a normal relation between systolic wall stress and ejection fraction . \n nevertheless , it has widely been associated with impaired long - term survival , myocardial infarction , sudden death , heart failure , and cerebrovascular accidents . \n therefore , lvmr is an important target in this kind of patient , due to the influence of residual lv hypertrophy on long - term survival [ 27 , 28 ] . \n lvmr ensues after the relief of lv outflow obstruction following aortic valve replacement , which leads to subsequent improved hemodynamics , clinical status , and prognosis . \n strain imaging is the most appropriate method to assess lv myocardial contractility as it is able to catch subclinical changes in lv performance in aortic stenosis patients [ 32 , 33 ] . \n in fact , peak longitudinal strain is reduced with increasing severity of aortic stenosis and , in addition , increased lv mass and higher relative wall thickness are associated with reduced lv regional and global myocardial deformation assessed by 2d speckle tracking . as a consequence , lv global longitudinal strain improves after surgical aortic valve replacement [ 13 , 36 ] . \n recently demonstrated that global longitudinal strain accurately predicts lvmr in patients with pure aortic stenosis undergoing surgical treatment . \n this study confirms data reported by our group in 2012 regarding lv diastolic function improvement and mass reduction after tavi . \n moreover , to the best of our knowledge , only a very recent study analyzed lv longitudinal strain 12 months after the cited procedure . \n moreover , our findings seem to extend the predictive value of baseline global longitudinal strain regarding lvmr after aortic valve replacement even in the tavi context . \n myocardial fibrosis in an aortic stenosis heart is responsible for lack of lvmr and poor clinical outcome . in this study \n we confirmed the hypothesis according to which impaired global longitudinal strain before aortic valve replacement ( tavi in this case ) may be due to a certain amount of fibrosis , thus conditioning future lack of lvmr and prognosis . \n importantly , our study deals with patients older than cited studies ( about 15 years older than spethmann s ) . \n this is the reason for a more reduced lv longitudinal strain than cited studies , even if our patients had all preserved lvef and no other cardiological comorbidities . \n first , the small number of patients and its retrospective nature limit its strength . however , this issue reflects the rarity of patients with severe aortic stenosis who underwent tavi and without any other cardiovascular disease . \n second , although performed by experienced echocardiographists , lv mass measurement and epicardial / endocardial border tracing for 2d strain analysis might be affected by potential errors . \n fourth , the small number of patients prevented us from carrying out a multivariate approach . \n in conclusion , baseline global longitudinal strain seems to predict lvmr in patients with pure aortic stenosis undergoing tavi . \n the assessment of global longitudinal strain , in addition to other echocardiographic parameters , may be helpful in detecting patients undergoing tavi who are unlikely to benefit from it .", "role": "user" }, { "content": "introductiontranscatheter aortic valve implantation is the option of choice for high surgical risk patients suffering from symptomatic aortic stenosis . \n we aimed to evaluate the influence of baseline global longitudinal strain on left ventricular mass regression after the procedure.methodswe enrolled 23 patients with pure symptomatic severe aortic stenosis who underwent corevalve prosthesis ( medtronic , minneapolis , \n mn ) implantation . \n everyone had echocardiography registration before the procedure and after six months in order to analyze two- , three- , and four - chamber peak longitudinal strain and global longitudinal strain.resultsafter the procedure new york heart association class , peak and mean aortic valve gradients ( p<0.001 for all ) improved . \n interventricular septum and posterior wall thicknesses decreased ( p<0.001 for both ) . \n moreover , left ventricular mass index for body surface area changed from 19044 to 14330 g / m2 , ( p<0.001 ) \n . finally , global longitudinal strain significantly increased ( from 9.40.9 to 11.50.8% ; p<0.001 ) , as well as its components . \n baseline global longitudinal strain correlated with left ventricular mass regression ( r=0.560 ; p=0.005 ; 2-sided ) and predicted it at linear regression analysis ( b=23.707 ; p=0.005 ; adjusted r2=0.281).conclusionsglobal longitudinal strain and its components improved six months after the procedure . \n moreover , baseline global longitudinal strain seemed to predict left ventricular mass regression in patients with pure aortic stenosis undergoing transcatheter aortic valve implantation . \n this finding could be related to the extent of myocardial fibrosis which is also responsible for lack of left ventricular mass regression and poorer prognosis .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: it aids the visualisation of lesions and directs biopsy from lesions that are thus visualised.1 biopsy specimens can be obtained using biopsy forceps , or brushings or transbronchial needle.1 for accurate biopsy , the lesions should be visualised through the bronchial tree ; hence , centrifugal lesions may not be accessed.23 this is the limitation of the procedure . \n bronchoscopy is an invasive procedure either done with the aid of a flexible or rigid bronchoscope . \n the biopsy specimens size obtained differ between instruments , with the rigid producing bigger tissues than the flexible.1 biopsy specimens obtained are generally between 1 and 2 mm in size.4 the flexible scope find better patient acceptance , since it is routinely done in the awake patient and as an outpatient procedure . \n however , apart from the smaller size of the specimen obtained , the tissues may be further crushed as they are retrieved through the port in the instrument.34 this may distort tissue integrity and affect histological diagnosis . \n these drawbacks have spurred the development of other means of increasing tissue size and yield notably the cryobiopsy technique.4 our study was done to evaluate our flexible bronchoscopic techniques , sizes and diagnostic yield . \n this is a retrospective study comprising all cases of bronchial biopsies done in the university of benin teaching hospital from 2007 to 2011 . during the period , \n all patients who had diagnostic flexible bronchoscopy under general anaesthesia under review were enrolled in the study . \n the data were obtained from the theatre , outpatient clinic records and collated and their clinical histories gleaned from the case notes for epidemiological and biodata . \n the data were analysed using statistical package for the social sciences ( spss ) 16 and the result presented in tables and graphs . \n biopsy was obtained using the olympus biopsy forceps and the specimens were immediately fixed in formalin solutions . \n they were subsequently embedded in paraffin wax and cut sections routinely stained with haematoxylin and eosin . \n the cell type was identified as squamous - cell , adenocarcinoma , oat - cell , or large - cell undifferentiated . \n the flexible bronchoscope was introduced through an appropriate sized endotracheal tube via a connector such that continuous patient ventilation by the anaesthetist was still feasible [ figure 1 ] . a bronchoscope and adaptor the biopsy forceps was used to take 4 - 5 biopsy specimens . \n these were all at the sites of visualised lesions or points of apparent bronchial distortions . \n there were challenges with tissue samples by the histopathologist with multiple consultations , inadequacy of samples were adjudged from crushed tissues , poor staining and unrepresentative tissues . \n the mean tissue biopsy size was 2.0 mm with a range of 1 - 5 mm . \n table 1 shows the distribution of the histological diagnosis with a majority being inadequate for diagnosis and 25% showing carcinoma . \n histological diagnosis table 2 shows the frequency distribution of the histological diagnosis of the lung cancers with squamous cell carcinoma being the predominant histological type . \n histology of the lung tumour table 3 shows the indications for the bronchoscopy and biopsy , with suspicious lesions on chest radiograph and unremitting cough being the commonest indications . \n indication for bronchoscopy table 4 shows the accuracy of the biopsy specimen compared with the overall final diagnosis in these patients . \n the indication for biopsy was a combination of clinical symptoms and signs together with lesions seen on chest x - ray . \n this coincides with the approved guidelines by the british thoracic society ( bts ) as bronchoscopy is an important tool for resolving the diagnostic problem.5 lung tumour was an important differential in all the patients in the study . \n biopsy , in these instances , provides tissue specimens for histological diagnosis.56 lesions found on chest radiographs formed the main reason for referral for bronchoscopy . \n bronchoscopy , therefore , helps to resolve the diagnosis.123 biopsy sizes showed a similarity with tissue sizes obtained from other studies.478 tissue histology results were adequate for histological diagnosis only in eight patients . in only one case \n other investigations including percutaneous biopsy and open lung biopsy with sputum cytology were employed in all patients to increase diagnostic accuracy.8910 the indications in this study highlight the importance of the biopsy specimen for obtaining diagnosis and directing the course of treatment . \n the finding of 50% usefulness in this study was low compared to work done in other centres.7 this may be due to the tissue handling of small specimens and possibly presence of unrepresentative tissues in the specimen collected . \n other workers have demonstrated the improved usefulness of cryobiopsies.410 multiple biopsies is the rule , at least five being adjudged the best for obtaining adequate tissue with probability of appropriate tissue diagnosis.2 the site of biopsy is important in obtaining representative tissue for histopathology . \n biopsy obtained from sites of extrinsic bronchial impression have a smaller yield of about 25% as against > 75% for directly visualised bronchial lesions.357 all three patients with adenocarcinoma had unrepresentative biopsy specimens , which diagnosis was only confirmed either at thoracotomy or transthoracic lung and pleural biopsy . \n rigid bronchoscopy was not used in any of the patients as the combination of flexible bronchoscopy and transthoracic lung and pleural biopsy in combination with cytology sufficed in establishing the diagnosis in all patients . \n however , its use may have improved the sensitivity of bronchoscopic biopsies since it does not have the drawback of smaller tissue sample sizes , crushing of specimen seen in flexible bronchoscopes , however , it has limitation in the reach within the bronchial tree.13 \n bronchoscopic biopsies are fraught with problems and other clinical investigative tools would certainly be important in improving the results .", "role": "user" }, { "content": "aim : our study was done to evaluate our bronchoscopic techniques , sizes and diagnostic yield.materials and methods : this was a retrospective study comprising all cases of bronchial biopsies done in the university of benin teaching hospital from 2007 to 2011 . \n all patients who had flexible bronchoscopy under general anaesthesia during the period under review where enrolled in the study.results:there were a total of 16 patients : nine males and seven females , with a mean age of 46.9 years . \n the main indications were cough ( 87.5% ) , weight loss ( 62.5% ) , x - ray findings of a chest lesion ( 87.5% ) , chest pain ( 62.5% ) , difficulty with breathing ( 31.3% ) and massive haemoptysis ( 25% ) . \n histology results showed inadequate samples in six and bronchogenic carcinoma in four patients . \n the histology was pivotal in eight patients.conclusion:bronchoscopic biopsies are fraught with problems and other clinical investigative tools would certainly be important in improving the results .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: approximately 35 per cent of hospital admissions in england are classified as emergency admissions , costing approximately 11 billion a year . \n emergency admission rates in england have been rising relentlessly for many years but now there is an acute need to reduce emergency admission rates because of the combined pressures of rising health care costs , an ageing population , the increasing prevalence of various chronic diseases and a tightening of health care budgets . \n the costs of hospital care are highly concentrated in the population , with just 5% of inpatients in england accounting for 49% of inpatient bed days . \n if admission rates could be reduced for these very costly patients then large net savings might be possible , even if the costs of the preventive care were high . however , some disappointing results from government - funded trials of hospital avoidance schemes , such as the uk evercare pilots , the medicare health support experiment and the medicare coordinated care demonstration , are a reminder how difficult it can be to make these potential savings [ 57 ] . \n one reason why hospital avoidance interventions may fail is if they are offered to patients who are not truly at high risk of emergency admission . \n for example , the uk evercare programme , which involved a comprehensive assessment and ongoing monitoring , was offered to patients aged 65 years and older who had experienced two or more hospital admissions in the preceding 12 months . however , today s high - cost patients may have markedly lower average costs in the future even without intervention due to the phenomenon of regression to the mean. indeed , an analysis of the uk evercare pilots by gravelle and colleagues showed that there was actually no reduction in admission rates above what would have happened anyway due to regression to the mean [ 7 , 8 ] . \n this suggests that hospital - avoidance programmes are best offered according to the risk of future hospitalization rather than being offered to patients who are currently experiencing multiple hospital admissions . \n one way to identify patients at risk of future hospitalization is to use a predictive risk model . in 2004 , \n the english strategic health authorities and the department of health commissioned two such models for the nhs in england : the patients at risk of rehospitalisation tool ( parr ) and the combined predictive model [ 10 , 11 ] . the ways in which these models are used in practice varies across the country . in many areas \n they have been used to find patients for community matrons or other case managers to work with , or used to select which patients should be offered telephone - based health coaching and advice . \n elsewhere , they have been used to identify patients who are offered multidisciplinary integrated care in the form of virtual wards ( vws ) . \n integrated care has been defined as , a coherent set of methods and models on the funding , administrative , organisational , service delivery and clinical levels designed to create connectivity , alignment and collaboration within and between the cure and care sectors [ 12 , p. 3 ] . \n stronger co - ordination and collaboration between the primary , community and social care sectors is regarded as essential for the provision of high quality , safe and efficient services to people living with complex , long - term health and social care needs [ 1216 ] . \n previous studies have identified a range of essential ingredients for the delivery of high quality integrated care [ 12 , 16 ] . \n rosen and ham ( 2008 ) classify these as macro ( policy , financial and regulatory environment ) , \n meso ( organisational and clinical structures and processes ) , and micro ( patient interactions with different individuals and teams ) levels of integration . \n the current study will use the example of virtual wards [ 18 , 19 ] , which aim to integrate primary , community and social care at the meso ( service delivery ) and micro ( clinical ) levels . \n it will explore the cost - effectiveness of this type of integrated , multidisciplinary case management in reducing emergency hospital admissions for patients at high predicted risk , as well as any impact on social care services . \n the original model for virtual wards was described by lewis in 2006 ( see box 1 ) . \n vws seek to improve integration through a number of strategies , including a shared record , multidisciplinary team meetings ( ward rounds ) and an automated alert system for informing vw staff when a patient accesses another care service , such as attending a local emergency department . \n patients identified by a predictive risk model as being at high risk of a future emergency hospital admission are offered \n vws use the systems , staffing and daily routines of a hospital ward , however , there is no physical ward building hence the term \n virtual. vw patients receive multidisciplinary preventive care at home through a combination of home visits and telephone - based care . \n each vw has a fixed number of beds ; once these beds are full , no more patients can be admitted to the vw until a bed becomes available . \n the composition of the vw multidisciplinary team will vary according to the needs of local high - risk patients . \n it may include a community matron , district nurses , a ward clerk , pharmacist , social worker , physiotherapist , occupational therapist , mental health professional and a representative from the voluntary sector etc . \n medical input comes from the duty doctor at each constituent gp practice as well as from the patient s usual gp . \n the role of the administrator ( ward clerk ) is seen as being pivotal in supporting and co - ordinating members of the vw staff . \n systems are put in place to notify local hospitals , nhs direct , the local ambulance trust and gp out - of - hours cooperatives about which patients are being cared for on each vw . \n this information is used to alert vw staff automatically should a vw patient present to any of these services ( e.g. to a local a&e department ) . \n the current study will evaluate three examples of virtual wards in practice ( see table 2 ) . \n there are several reasons why integrated , multidisciplinary preventive care might be beneficial to high - risk patients . \n such patients are typically older people with multiple chronic conditions and complex health and social needs . often , \n this can lead to problems of duplication ( where several professionals deliver the same care ) and , equally , of gaps in care ( where no professional delivers a particular element of care , perhaps because they wrongly assume that it is being delivered or secured by another professional ) . \n some theoretical advantages of vws over case management by an individual case manager are that the vw staff may have the capacity to cover each other for sickness leave and annual leave and thereby provide a more continuous service ; vw ward rounds may provide an added degree of discipline in that members of the vw team may feel compelled to prepare for the vw ward round in the same way that junior doctors in a hospital prepare for consultant ward rounds ; and vw team members may be restrained by peer pressure from spending disproportionate amounts of time and effort with any particular patients to the relative neglect of other vw patients . \n however , there is as yet no robust evidence of virtual wards efficacy in reducing unplanned admissions , or of their cost - effectiveness . \n as reported by gravelle and colleagues , a systematic review of home - based support for older people found no overall impact of such care on hospital admission rates , where as a review of integrated care pilots for older people suggested that they can reduce admission rates and costs of care , but that the effects are highly dependent on the system concerned [ 7 , 21 , 22 ] . \n two other reviews concluded that there is limited evidence that case management reduces the use of health services , but both reviews suggested that the results of individual studies may not be generalizable [ 23 , 24 ] . \n moreover , there is little evidence to date on the optimal configuration of community - based hospital avoidance initiatives . in england , \n department of health guidance recommends that community matrons should have a caseload of 5080 patients . \n however , it is unclear whether this is truly the optimal number of patients in terms of quality and effectiveness . \n an analysis of the caseloads of 46 case managers concluded that higher case loads were associated with more reactive care and with increased hospital admissions . \n this finding suggests that any intervention designed to reduce hospital interventions may be rendered ineffective if the caseloads are too large . \n however , whilst in general , smaller caseloads would be expected to increase the quality of a service , such increased quality might not be cost - effective . \n clearly , then , this caseload vs. quality trade - off is of critical importance to case management , and it depends centrally on the types of patient seen , i.e. the case mix of patients . \n integrated care has been defined as , a coherent set of methods and models on the funding , administrative , organisational , service delivery and clinical levels designed to create connectivity , alignment and collaboration within and between the cure and care sectors [ 12 , p. 3 ] . \n stronger co - ordination and collaboration between the primary , community and social care sectors is regarded as essential for the provision of high quality , safe and efficient services to people living with complex , long - term health and social care needs [ 1216 ] . \n previous studies have identified a range of essential ingredients for the delivery of high quality integrated care [ 12 , 16 ] . \n rosen and ham ( 2008 ) classify these as macro ( policy , financial and regulatory environment ) , \n meso ( organisational and clinical structures and processes ) , and micro ( patient interactions with different individuals and teams ) levels of integration . the current study will use the example of virtual wards [ 18 , 19 ] , which aim to integrate primary , community and social care at the meso ( service delivery ) and micro ( clinical ) levels . \n it will explore the cost - effectiveness of this type of integrated , multidisciplinary case management in reducing emergency hospital admissions for patients at high predicted risk , as well as any impact on social care services . \n the original model for virtual wards was described by lewis in 2006 ( see box 1 ) . \n vws seek to improve integration through a number of strategies , including a shared record , multidisciplinary team meetings ( ward rounds ) and an automated alert system for informing vw staff when a patient accesses another care service , such as attending a local emergency department . \n patients identified by a predictive risk model as being at high risk of a future emergency hospital admission are offered \n vws use the systems , staffing and daily routines of a hospital ward , however , there is no physical ward building hence the term \n virtual. vw patients receive multidisciplinary preventive care at home through a combination of home visits and telephone - based care . \n each vw has a fixed number of beds ; once these beds are full , no more patients can be admitted to the vw until a bed becomes available . \n each vw is linked to a small number of specific gp practices . specialist staff ( e.g. a cardiac nurse specialist ) may work across several vws . \n the composition of the vw multidisciplinary team will vary according to the needs of local high - risk patients . \n it may include a community matron , district nurses , a ward clerk , pharmacist , social worker , physiotherapist , occupational therapist , mental health professional and a representative from the voluntary sector etc . \n medical input comes from the duty doctor at each constituent gp practice as well as from the patient s usual gp . \n the role of the administrator ( ward clerk ) is seen as being pivotal in supporting and co - ordinating members of the vw staff . \n systems are put in place to notify local hospitals , nhs direct , the local ambulance trust and gp out - of - hours cooperatives about which patients are being cared for on each vw . \n this information is used to alert vw staff automatically should a vw patient present to any of these services ( e.g. to a local a&e department ) . table 1 describes the vw intervention using the taxonomy described by roland and colleagues . \n the current study will evaluate three examples of virtual wards in practice ( see table 2 ) . \n there are several reasons why integrated , multidisciplinary preventive care might be beneficial to high - risk patients . \n such patients are typically older people with multiple chronic conditions and complex health and social needs . \n this can lead to problems of duplication ( where several professionals deliver the same care ) and , equally , of gaps in care ( where no professional delivers a particular element of care , perhaps because they wrongly assume that it is being delivered or secured by another professional ) . \n some theoretical advantages of vws over case management by an individual case manager are that the vw staff may have the capacity to cover each other for sickness leave and annual leave and thereby provide a more continuous service ; vw ward rounds may provide an added degree of discipline in that members of the vw team may feel compelled to prepare for the vw ward round in the same way that junior doctors in a hospital prepare for consultant ward rounds ; and vw team members may be restrained by peer pressure from spending disproportionate amounts of time and effort with any particular patients to the relative neglect of other vw patients . \n however , there is as yet no robust evidence of virtual wards efficacy in reducing unplanned admissions , or of their cost - effectiveness . \n as reported by gravelle and colleagues , a systematic review of home - based support for older people found no overall impact of such care on hospital admission rates , where as a review of integrated care pilots for older people suggested that they can reduce admission rates and costs of care , but that the effects are highly dependent on the system concerned [ 7 , 21 , 22 ] . \n two other reviews concluded that there is limited evidence that case management reduces the use of health services , but both reviews suggested that the results of individual studies may not be generalizable [ 23 , 24 ] . \n moreover , there is little evidence to date on the optimal configuration of community - based hospital avoidance initiatives . in england , \n department of health guidance recommends that community matrons should have a caseload of 5080 patients . \n however , it is unclear whether this is truly the optimal number of patients in terms of quality and effectiveness . \n an analysis of the caseloads of 46 case managers concluded that higher case loads were associated with more reactive care and with increased hospital admissions . \n this finding suggests that any intervention designed to reduce hospital interventions may be rendered ineffective if the caseloads are too large . \n however , whilst in general , smaller caseloads would be expected to increase the quality of a service , such increased quality might not be cost - effective . clearly \n , then , this caseload vs. quality trade - off is of critical importance to case management , and it depends centrally on the types of patient seen , i.e. the case mix of patients . \n for this study , we will conduct a retrospective analysis of the vws in croydon , devon and wandsworth using routine , person - level data . \n only pseudonymous data will be used , i.e. data from which all sensitive fields such as names and addresses have been removed , and the unique key ( nhs number ) has been replaced by a unique , meaningless pseudonym . \n we will obtain pseudonymous nhs numbers of all patients admitted to the vws in the three sites , together with their dates of admission and dates of discharge , or of death if relevant . \n we will also obtain hospital episode statistics ( he s ) for the whole of england . and \n we will obtain pseudonymous extracts for the whole registered populations of croydon , devon and wandsworth relating to hospital activity from the secondary uses service ( sus ) ; primary care clinical data from gp electronic systems ; community health services data and social care data from local operational systems ; and mortality data from the office for national statistics ( ons ) . \n these datasets will allow us to track the use of care services by the three populations and provide us with a range of explanatory variables . within these data \n , we will be able to identify those individuals who received the vw intervention , and we will create comparator groups that match these people as closely as possible . \n two comparison groups will be created for each site : \n patients drawn from comparable areas of england ( ons corresponding health areas ) that do not have vws ( national controls ) . \n these patients will be matched using hospital ( he s ) data and mortality data.patients drawn from the same pct who were not admitted to a vw ( local controls ) . \n these patients will be matched using a combination of hospital ( sus ) data , gp clinical data , community health services data , social care data and mortality data . \n patients drawn from comparable areas of england ( ons corresponding health areas ) that do not have vws ( national controls ) . \n these patients will be matched using hospital ( he s ) data and mortality data . \n patients drawn from the same pct who were not admitted to a vw ( local controls ) . \n these patients will be matched using a combination of hospital ( sus ) data , gp clinical data , community health services data , social care data and mortality data . \n we will control for the observed differences between vw patients and control patients by selecting one or more control patients for each vw patient . \n these control patients will be chosen on the basis that they were similar in terms of a range of observed characteristics prior to the start of the intervention . \n two methods will be used to ensure that the control group is as similar as possible to the intervention group across a distribution of characteristics , namely propensity score matching and prognostic matching ( see box 2 ) . \n propensity score matching one well - established method for selecting controls is to estimate the propensity score , which is defined as the probability that an individual will receive the intervention , conditional on the characteristics observed at a given point of time . \n the theory suggests that selecting controls on the basis of having similar propensity scores to the vw patients should reduce or eliminate any imbalances in observed characteristics asymptotically , assuming that the propensity score has been correctly estimated . in practice , however , with a finite number of patients , some differences may remain between vw patients and matched controls , even if matching on a correctly estimated propensity score . \n one recommended approach to improve the balance in these circumstances is to match on a variety of variables simultaneously , including the propensity score and other important characteristics . \n this can be accomplished by the use of a multivariate distance measure , such as the mahalanobis distance , to summarise the similarity of patients and potential controls over the range of variables . \n the individual with the smallest mahalanobis distance is selected as the matched control . on the assumption that there is no hidden bias caused by residual imbalances in unobserved characteristics \n , we will be able to obtain an unbiased estimate of the average impact of virtual wards on the subgroup of patients receiving the intervention by comparing the endpoints of virtual ward and control patients . \n propensity matching is regarded as an iterative approach , so we will successively improve the propensity model until we obtain a satisfactory balance . \n one of the key recommended conditions for the use of propensity matching is that the assignment mechanism for choosing patients for the intervention should be well understood . \n this condition is met for virtual wards , since patients are generally chosen using a predictive risk model . \n given the prominent role of predictive modelling in the intervention , we will also select controls by matching directly on the predictive risk score , combined with other relevant characteristics through a mahalanobis distance . \n this method of selecting controls is termed prognostic matching and should also produce an unbiased estimate of the average impact of virtual wards . \n we will compare the prognostic and propensity matching approaches , and our final set of controls will be chosen as those with the greater level of balance , as determined by accepted metrics . \n for the national controls these will include variables recorded in hospital episode statistics ( age , sex , imputed deprivation , distance to the nearest hospital , diagnoses , and patterns of inpatient , outpatient and a&e use ) . for the local controls \n these will include variables recorded in secondary uses service data ( equivalent to those recorded in he s ) plus variables recorded in gp data ( including prescribing data , laboratory results and biometrics ) , social care data ( social care needs assessments and service provision ) and community health services data ( services provided by district nurses , community physiotherapists etc . ) . the primary endpoint for this study will be comparative rates of unplanned hospital admission and mortality . \n the secondary endpoints will be the rates and cost of a&e attendances , cost of social care provision , rates and cost of gp visits , and cost of community health services . \n each of the primary and secondary outcome endpoints will be measured at the individual patient level over the 90 days , 180 days and 360 days following admission to the vw , and compared to the outcomes of the matched controls . to estimate the required number of patients for a study such as this \n , an assumption needs to be made about the magnitude of the change that it is reasonable to expect the intervention to generate . \n we have designed this study so that , with reasonably high probability , we will detect a relative change of 20% in the primary endpoint , should it occur , at power ( 1-type ii error ) 90% and two - sided p - value ( type i error ) < 0.05 . based on actual data provided by one of the sites \n , we shall take the rate of unplanned hospital admission to be 1.65 unplanned admissions per year with a standard deviation of 2.5 for patients receiving usual care . using the formulae provided by friedman and colleagues \n we will assess any differences in rates of health and social care utilisation between vw patients and matched controls using paired t - tests . we do not plan to conduct any subgroup analyses \n . we will calculate the direct costs of the vws in each of the three sites from the perspectives of the nhs and the local authority . \n in the three sites , the alternative to vw care is routine care . to establish the cost of routine care \n , we will use data on the utilization of health and social care services , including gp visits , hospital costs ( inpatient , outpatient and a&e ) and council - funded social care . \n the unit costs will be calculated using the actual costs to the nhs ( hospital tariff , gp hourly rates etc . ) . \n social care costs will be calculated according to activity recorded in social care data , multiplied by the unit costs published by the personal social services research unit . as well as using financial data from each site \n , the costs of the intervention will be validated by means of staff interviews , questionnaires and work diaries . \n the costs considered will include : \n staff costs : these will be calculated for full - time virtual ward staff plus 25% on - costs . those staff that split their time between vw activities and non - vw activities \n will be calculated pro - rata on the basis of diaries in which they will record the amount of time spent on vw activities for a sample two - week period.travel costs : these will be calculated on the basis of the reimbursement for public transport or mileage paid to staff.land , computers and fixed capital costs : these will be calculated on the basis of the lease costs paid for these items.management costs : these will be calculated on the basis of the costs of management time that will actively be spent on vw activity using full time equivalents and salary bands . \n staff costs : these will be calculated for full - time virtual ward staff plus 25% on - costs . those staff that split their time between vw activities and non - vw activities \n will be calculated pro - rata on the basis of diaries in which they will record the amount of time spent on vw activities for a sample two - week period . \n travel costs : these will be calculated on the basis of the reimbursement for public transport or mileage paid to staff . \n land , computers and fixed capital costs : these will be calculated on the basis of the lease costs paid for these items . \n management costs : these will be calculated on the basis of the costs of management time that will actively be spent on vw activity using full time equivalents and salary bands . \n we shall ignore pharmaceutical and laboratory costs because of the difficulties in obtaining the necessary data . \n we believe that these costs are unlikely to differ considerably between the intervention and control populations but we will attempt to check the reasonableness of this assumption during interviews of front - line staff . the set - up costs of the vws ( including generating the predictive risk scores ) will also be included in the cost estimates . \n we will ask the management and finance staff at each site what was entailed in setting up the vws . \n we will include all patients admitted to a vw between their inception at each site and 1 september 2010 . \n the vws in croydon started on 15 may 2006 ; in devon on 1 october 2008 ; and in wandsworth on 1 march 2009 . \n patients will be excluded if they were admitted to a vw after 1 september 2010 . for the comparator group we will include the following patients subject to the exclusions below : \n national all patients registered at the pct of an ons corresponding health arealocal all registered patients \n national all patients registered at the pct of an ons corresponding health area local all registered patients to ensure that the care provided to vw patients is different from the care provided to controls \n , we will exclude the following patients from the comparator group : \n national all patients registered at the pct of an ons corresponding health area that has a virtual ward scheme or similar in place during the period under study ( which we have determined by contacting the local pct).local all patients who have ever been admitted to a virtual ward . \n national all patients registered at the pct of an ons corresponding health area that has a virtual ward scheme or similar in place during the period under study ( which we have determined by contacting the local pct ) . \n the primary endpoint for this study will be comparative rates of unplanned hospital admission and mortality \n . the secondary endpoints will be the rates and cost of a&e attendances , cost of social care provision , rates and cost of gp visits , and cost of community health services . \n each of the primary and secondary outcome endpoints will be measured at the individual patient level over the 90 days , 180 days and 360 days following admission to the vw , and compared to the outcomes of the matched controls . \n to estimate the required number of patients for a study such as this , an assumption needs to be made about the magnitude of the change that it is reasonable to expect the intervention to generate . \n we have designed this study so that , with reasonably high probability , we will detect a relative change of 20% in the primary endpoint , should it occur , at power ( 1-type ii error ) 90% and two - sided p - value ( type i error ) < 0.05 . based on actual data provided by one of the sites \n , we shall take the rate of unplanned hospital admission to be 1.65 unplanned admissions per year with a standard deviation of 2.5 for patients receiving usual care . using the formulae provided by friedman and colleagues \n we will assess any differences in rates of health and social care utilisation between vw patients and matched controls using paired t - tests . we do not plan to conduct any subgroup analyses . \n we will calculate the direct costs of the vws in each of the three sites from the perspectives of the nhs and the local authority . in the three sites , \n the alternative to vw care is routine care . to establish the cost of routine care \n , we will use data on the utilization of health and social care services , including gp visits , hospital costs ( inpatient , outpatient and a&e ) and council - funded social care . \n the unit costs will be calculated using the actual costs to the nhs ( hospital tariff , gp hourly rates etc . ) . \n social care costs will be calculated according to activity recorded in social care data , multiplied by the unit costs published by the personal social services research unit . as well as using financial data from each site \n , the costs of the intervention will be validated by means of staff interviews , questionnaires and work diaries . \n the costs considered will include : \n staff costs : these will be calculated for full - time virtual ward staff plus 25% on - costs . those staff that split their time between vw activities and non - vw activities \n will be calculated pro - rata on the basis of diaries in which they will record the amount of time spent on vw activities for a sample two - week period.travel costs : these will be calculated on the basis of the reimbursement for public transport or mileage paid to staff.land , computers and fixed capital costs : these will be calculated on the basis of the lease costs paid for these items.management costs : these will be calculated on the basis of the costs of management time that will actively be spent on vw activity using full time equivalents and salary bands . \n staff costs : these will be calculated for full - time virtual ward staff plus 25% on - costs . those staff that split their time between vw activities and non - vw activities \n will be calculated pro - rata on the basis of diaries in which they will record the amount of time spent on vw activities for a sample two - week period . \n travel costs : these will be calculated on the basis of the reimbursement for public transport or mileage paid to staff . \n land , computers and fixed capital costs : these will be calculated on the basis of the lease costs paid for these items . \n management costs : these will be calculated on the basis of the costs of management time that will actively be spent on vw activity using full time equivalents and salary bands . \n we shall ignore pharmaceutical and laboratory costs because of the difficulties in obtaining the necessary data . \n we believe that these costs are unlikely to differ considerably between the intervention and control populations but we will attempt to check the reasonableness of this assumption during interviews of front - line staff . \n the set - up costs of the vws ( including generating the predictive risk scores ) will also be included in the cost estimates . \n we will ask the management and finance staff at each site what was entailed in setting up the vws . \n we will include all patients admitted to a vw between their inception at each site and 1 september 2010 . \n the vws in croydon started on 15 may 2006 ; in devon on 1 october 2008 ; and in wandsworth on 1 march 2009 . \n patients will be excluded if they were admitted to a vw after 1 september 2010 . for the comparator group we will include the following patients subject to the exclusions below : \n national all patients registered at the pct of an ons corresponding health arealocal all registered patients \n national all patients registered at the pct of an ons corresponding health area local all registered patients to ensure that the care provided to vw patients is different from the care provided to controls \n , we will exclude the following patients from the comparator group : \n national all patients registered at the pct of an ons corresponding health area that has a virtual ward scheme or similar in place during the period under study ( which we have determined by contacting the local pct).local all patients who have ever been admitted to a virtual ward . \n national all patients registered at the pct of an ons corresponding health area that has a virtual ward scheme or similar in place during the period under study ( which we have determined by contacting the local pct ) . \n ethics approval was sought for this study because it will involve interviews , questionnaires and diaries administered to nhs and social care staff . \n participation by staff will be entirely voluntary , and staff invited to participate will receive both a consent form and a covering letter , explaining that participation is voluntary and that the study will deliver anonymous returns . to protect the confidentiality of study participants , each participant will be assigned a unique study identification number . the evaluation team will not request or receive any identifiable patient data : only pseudonymous or anonymous data will be obtained . for this reason , \n we have been advised by the ethics and confidentiality committee of the national information governance board that we may use such data without recourse to section 251 of the national health service act 2006 ( previously section 60 of the health and social care act 2001 ) . \n many health care organisations use predictive models to identify patients at high risk of unplanned hospital admission , so that they can offer these patients extra upstream support aimed at keeping them healthier and hopefully avoid the need for emergency admissions \n downstream. in certain parts of the uk , including croydon , devon and wandsworth , such people are offered extra , highly integrated , support through a system of virtual wards ( vws ) . \n vws aim specifically to prevent unplanned hospital admissions by using the same staffing , systems and daily routines as a hospital ward , except that the patients being cared for live in their own homes throughout . \n the research project outlined in this paper will evaluate the costs of running vws and the potential benefits of any reduced use of health and social care in three areas of england : croydon , devon and wandsworth . \n the research findings should help councils and nhs commissioners to decide whether to fund this type of integrated care and , if so , how best to configure and run vws locally . \n sandra birnie , msc , ba , ndn , rgn , service development manager , community care western cheshire , cheshire and wirral partnership , 1829 building , countess of chester health park , liverpool road , chester , ch2 1hj , uk natasha curry , health policy fellow , health policy deparment , the king s fund , 11 - 13 cavendish square , w1 g 0an london , uk jacqueline cumming , associate professor , phd , ma , director health services research centre , school of government , victoria university of wellington , room 315 , government building , 55 lambton quay , pipitea campus , wellington , new zealand", "role": "user" }, { "content": "backgroundthis retrospective study will assess the extent to which multidisciplinary case management in the form of virtual wards ( vws ) leads to changes in the use of health care and social care by patients at high risk of future unplanned hospital admission . \n vws use the staffing , systems and daily routines of a hospital ward to deliver coordinated care to patients in their own homes . \n admission to a vw is offered to patients identified by a predictive risk model as being at high risk of unplanned hospital admission in the coming 12 months.study design and data collection methodswe will compare the health care and social care use of vw patients to that of matched controls . \n controls will be drawn from ( a ) national , and ( b ) local , individual - level pseudonymous routine data . \n the costs of setting up and running a vw will be determined from the perspectives of both health and social care organizations using a combination of administrative data , interviews and diaries.methods of analysisusing propensity score matching and prognostic matching , we will create matched comparator groups to estimate the effect size of virtual wards in reducing unplanned hospital admissions.conclusionsthis study will allow us to determine relative to matched comparator groups : whether vws reduce the use of emergency hospital care ; the impact , if any , of vws on the uptake of primary care , community health services and council - funded social care ; and the potential costs and savings of vws from the perspectives of the national health service ( nhs ) and local authorities .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: echinococcosis or hydatid disease ( hd ) is a parasitic disease infected by a cystic larval form of the cyclophyllidean tapeworm , echinococcus . \n human is one of its intermediate hosts , which include sheep , cattle , goats , rodents , marsupials , and other herbivorous mammals . \n four taxonomically relevant species of the genus echinococcus are infecting humans ; e. granulosus , e. multilocularis , e. vogeli , and e. oligarthrus . among them , e. granulosus and e. multilocularis mainly cause zoonotic infections of public health importance , cystic echinococcosis ( ce ) and alveolar echinococcosis ( ae ) , respectively . the remaining 2 species may infect humans but are rarely found in limited areas of south america . both ce and ae are distributed globally as endemic diseases of pastoral environment and commonly found among sheep- or cattle - raising people . \n ce commonly involves the liver and lungs but ae involves almost the liver in humans . \n however , cases of hd occur worldwide nowadays and regarded as a global emerging disease . \n moreover , patients with unusual , atypical , or complex type of hd have been reported increasingly . \n furthermore , hd is often confused with malignancy or other diseases in non - endemic areas . \n since hd develops silently , it used to be neglected in public health points of view , and most of the cases face difficulty for rapid and correct diagnosis in non - endemic areas . though echinococcosis is not endemic in korea , 33 cases of ce and 1 case of ae have been reported . \n a 25-year - old uzbek male was referred to the department of surgery , dongsan medical center , daegu , korea on 8 january 2012 , due to a cystic mass in the liver which was found by computed tomography at a private clinic . \n he had no history of past illness and denied any contact history with domestic animals or pets as well as livestock in uzbekistan . on physical examination , \n icterus was absent , and mild tenderness was recognized in the right upper abdomen without any palpable mass . \n he showed normal ranges of hemoglobin , white blood cell counts , including eosinophils , electrolyte profiles , and chemistry , including liver enzymes and bilirubin . \n his tumor markers , alpha - fetoprotein , carcinoembryonic antigen , and carbohydrate antigen 19 - 9 , were within normal limit . \n ct from a private clinic recognized a 109 cm - sized hypoattenuating mass with focal wall calcifications at the liver segment 7 ( fig . \n 1 ) . ultrasound examinations observed an oval and well - encapsulated echogenic mass with internally compactly filled tubular structures in the subcapsular location of the right posterior liver . \n mr image showed an oval mass with heterogeneous contents and without further contrast enhancement of this mass after intravenous administration of mr contrast ( primovist ; bayer healthcare , seoul , korea ) . \n serologic test by elisa to detect specific antibodies to parasite antigens , including echinococcus , clonorchis sinensis , paragonimus westermani , cysticercus , and sparganum ( absorbance at 450 nm ) was in negative ranges . \n regardless of this uncertain clinical setting , the liver mass was strongly suspected as parasitic because ultrasonography showed a round cyst with tubular folding contents . \n moreover , because the patient had a large atypical cystic mass , and abdominal pain appeared suddenly and progressed continuously , surgical resection of the mass was decided . \n 1 ) . grossly , the right hepatic mass showed a relatively well - demarcated , round , pale tan to red , smooth and cystic appearance , measuring 10.58.74.2 cm and 163.5 g. the cut - surface of the right hepatic mass showed a large unilocular cyst , containing olive - colored soft and flabby membrane attached with several small spherical brown clayish and soft nodules ( fig . \n microscopically , the hepatic mass consisted of outer thick adventitial layer , thick laminated gelatin layer in the middle , and inner thin germinal layer with numerous scattered protoscolices of e. granulosus in bile - tinged fluid and necrotic debris . \n 2 ) . some of them looked degenerated , and some of them were found intact in their morphology . although thick bile like content was filled in the cystic mass , biliary communication was not noticed . \n after the surgery , the patient recovered his health well and was discharged on the 8th hospital day without any complication . \n the patient had been working well without evidence of recurrence for 6 months after the operation . \n the clinical diagnosis should include differential diagnosis of ce and its staging before any intervention because ce is a chronic years - long disease which is treated by several options according to its stage . \n the stage of ce was classified by who experts in 2003 and reproposed in relation with diagnosis and treatment in 2010 . \n for management of clinically diagnosed ce , one option among surgical removal , drainage and chemotherapy , chemotherapy alone , and watch and wait is recommended according to its stage and size . \n the cystic mass of the present case was diagnosed as ce based on images and histopathologic findings . \n his ct findings recognized a spherical cyst with calcification in the right liver segment 7 . \n the ultrasound images visualized little fluid in the cyst but folding materials showed an image of so - called \" ball of wool \" ( fig . \n the gross findings of the surface or cut - edge of the present cyst were also looking inactive ( fig . \n the present cyst was filled not by clear cystic fluid but by folding septum and gelatin tissue mixed with thick bile - stained mucus . \n this cyst finding is compatible with a process of natural degeneration of inactive ce , and the same degenerating process has been described after chemotherapy . \n the histopathological finding of the present liver cyst demonstrated typical microscopic morphology of ce ( fig . \n the ball of wool in the mass by ultrasound scanning was images of septations and folds in the cyst . \n however , the cyst wall was well - outlined , and some protoscolices were found intact while many of them were degenerating ( fig . \n these morphologic findings were compatible with the stage ce4 as a whole , but there was a possibility of some remaining live protoscolices in the present ce . \n thousands of protoscolices are produced in 1 ce during the active stage but they may lose their viability one by one after the transition stage . the process may take a years - long period . \n although it is difficult to confirm their viability by morphologic findings , some of them might have been viable . \n serology of the present case was negative for specific igg antibodies to a fluid antigen of e. granulosus by elisa . \n the negative serology made clinical diagnosis of the present case difficult before the surgical intervention . \n the sensitivity of elisa using cystic fluid is known as 85 - 98% for liver cysts , 50 - 60% for lung cysts , and 90 - 100% for multiple organ cysts . \n clinically , the sensitivity is inversely related to the degree of sequestration of the echinococcal antigens in the cyst . \n ruptured cysts are associated with strong immune responses , whereas intact or healthy cyst can elicit a minimally detectable response . \n specific antibody levels of this patient against cyst fluid antigen by elisa revealed negative reaction . \n the elisa using fluid antigen demonstrated false negative reaction up to 15% possibly due to immune status of the infected individuals , especially in case of inactive ce . \n the present patient complained of progressive abdominal pain which was induced by the ce mass . \n the present cyst was compatible with the stage ce4 , which is inactive and managed by watch and wait . \n however , the present case had localized pain which was relieved by surgical resection of the ce . \n the pain must have originated by a complicated ce due to the big size of the cyst , 10.5 cm in diameter . in the present case , \n the cyst size was big which suggested he was infected several years before . since uzbekistan is an endemic area of ce , this patient should be an imported case of ce in korea . \n the present report describes clinical findings of an imported case of ce which represented ultrasound images of an inactive stage of ce4 . \n however , a few intact protoscolices may have remained in the cyst , and pain may have occurred due to the big size of the mass .", "role": "user" }, { "content": "a 25-year - old uzbek male presented with right upper abdominal pain for 20 days . on radiologic studies , a huge cystic mass was noticed in the right liver which was suspected as parasitic . \n the patient received right hepatic segmentectomy ( segment 7 ) , and the surgically resected mass was confirmed as cystic echinococcosis ( ce ) , measuring 10.5 cm in its diameter . \n the inner surface of the cyst was bile - stained . \n the patient was discharged on the 8th hospital day , and was rechecked 6 months after the surgical intervention without any evidence of recurrence . \n the present report describes findings of an imported case of ce which represented ultrasound images of the ' ball of wool ' .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: the heterocyclic hydrazones constitute an important class of biologically active drug molecules which have attracted attention of medicinal chemists due to their wide ranging pharmacological properties including iron scavenging and antitubercular activities [ 1 - 6 ] . \n the hydrazones have also been used as herbicides , insecticides , nematocides , redenticides , and plant growth regulators as well as plasticizers and stabilizers for polymers . \n furthermore , some hydrazones are used as quantitative analytical reagents , especially in colorimetric and fluorimetric determination of metal ions [ 4 - 6 ] . \n the importance of the phenolic quinolyl hydrazones arises from incorporating the quinoline ring with the phenolic compound ; 2,4-dihydroxybenzaldehyde . \n quinoline ring has therapeutic and biological activities whereas , phenols have antiseptic and disinfectants activities and are used in the preparation of dyes , bakelite and drugs . \n the metal complexes of hydrazones have potential applications as catalysts , luminescent probes and molecular sensors . \n the present study is planned to check the effect of the counter anions on the type and geometry of the isolated copper(ii)- complexes as well as the ligational behavior of the phenolic hydrazone ; 4-[(2-(4,8-dimethylquinolin-2-yl)hydra - zono)methyl]benzene-1,3-diol ; ( h2l ) . \n this work is an extension to our previous studies on the chelating ability of quinolyl hydrazones [ 12 - 14 ] . \n the investigated hydrazone ; 4-[(2-(4,8-dimethylquinolin-2-yl)hydrazono)methyl ] benzene-1,3-diol ; ( h2l ) was prepared by a condensation reaction of 2-hydrazinyl-4,8-dimethylquinoline with 2,4-dihydroxybenzaldehyde . \n the results of elemental analysis ( table 1 ) are in good harmony with the proposed formula . the ir spectrum ( table 2 ) showed bands at 3426 , 3159 and 1603 cmassignable to (oh ) , (nh ) and (c = n ) ; respectively . on the other hand , the electronic absorption spectra of the hydrazone in dmf exhibit two intense bands at 266 and 320 nm characteristic for - * transitions of the aromatic and c = n group , respectively . \n in addition , the band at 371 nm referred to a charge transfer ( ct ) transition . \n the mass spectrum of the ligand showed the molecular ion and the base peaks at m / z = 307 and 172 confirming its formula weight ( fw = 307.35 ) . the mass fragmentation pattern ( scheme 1 ) supported the suggested structure of the ligand . \n also , the h nmr spectral data of the ligand in d6-dmso relative to tms ( figure 1 ) lend a further support of its structure . the signals due to oh and nh protons are disappeared upon deuteration . analytical and physical data of the copper(ii)- phenolic complexes . magnetic , conductivity , electronic and ir spectral data for the copper(ii)- phenolic complexes \n hnmr spectrum of the phenolic hydrazone ; = 7.05 - 7.73 for aromatic protons ( 7h ) . \n the interaction of the phenolic hydrazone ( h2l ) with several copper(ii)- salts afforded mono- and binuclear as well as dimeric complexes depending on the type of the anion ; scheme 2 . \n the dimeric ( 1 & 5 ) and the binuclear ( 2 ) complexes are formed via phenoxy bridging . in general , the isolated complexes reflect the strong coordinating power of the so4 , aco , br , cl and no3 anions relative to the non coordinating clo4 anion . \n also , they reflect a variety of modes of bonding as well as various geometries ( octahedral , square pyramid and square planar ) depending on the type of the counter anion ( scheme 2 ) . \n in addition , complexes ( 2 - 4 & 6 ) reveal the highest affinity of copper(ii)-ions for n - donors . for square pyramidal complexes ( 1,2 & 4 ) , \n structural elucidation of the isolated complexes was achieved via elemental and thermal analyses , magnetic susceptibility and conductivity measurements as well as spectral studies viz . electronic , vibration , mass and esr spectra . \n comparison of the ir bands of the free phenolic hydrazone ( h2l ) and its complexes revealed the following : ( i ) all complexes showed broad bands in the region 3423 - 3385 cmdue to oh stretches of either the phenolic or the associated water / methanol molecules . \n ( ii ) the strong band at 1603 cmassignable to (c = n ) stretch in the free ligand undergoes a shift to higher wave numbers ( 1641 - 1612 cm ) upon complexation , supporting the coordination of the hydrazone linkage to all metal ions . \n this can be explained on the basis of the diminished repulsion between the lone pairs of electrons of the two adjacent n atoms upon complexation and hence , - electron delocalization . \n ( iii ) the perchlorato and sulfato complexes ( 1 & 6 ) showed the (s - o ) or (cl - o ) stretches around 1100 cm . \n also , the nitrato complex ( 2 ) showed the (n - o ) stretch at 1394 cm . \n ( iv ) in the acetato complex ( 5 ) , the new band at 1635 cm ; (c = o ) , confirm the monodentate nature of the acetate ion . \n the molar conductance values ( table 2 ) of the current chelates in dmf ( 1.0 mmol / l ) revealed a non- electrolytic nature of all complexes except the perchlorato- complex ( 1 ) which showed molar conductance of 175 and ohmcmmolsuggesting its 1:2 electrolytic nature . \n the complex ( 1 ) has 3 mol ions / mol ( + 2 , -1 ) , one of which is bi- positive . in case of complexes 2 - 4 , \n the relatively high values of the molar conductance may be due to their partial dissociation in dmf solutions . \n however , they did not reach the previously reported values for 1:1 electrolytes in dmf solutions ( ~70 - 110 ohmcmmol ) . on the other hand , the copper(ii)- complexes ( 1 - 6 ) ; d - system exhibit eff values in the range 1.33 - 2.01 b.m . \n the subnormal eff values for complexes ( 1 , 2 & 5 ) indicate m--- minteractions in the solid state supporting either dimeric or binuclear nature of the complexes . \n solution electronic spectra of all phenolic complexes in dmf ( figure 2 & table 2 ) are more or less similar and show a series of bands within the range 269 - 352 nm due to different intra- ligand transitions . besides , the phenoxide to metal charge transfer band ( lmct transition ) appears in the range 371 - 381 nm . \n in addition , the copper ( ii)- complexes ( 1 - 6 ) display relatively less intense bands at 436 - 488 nm that arise from different d - d transitions of copper ( ii ) . the position and intensity of d - d bands suggest a distorted square planar , square pyramid or oh environment around copper ( ii)- ion . to obtain further information about the stereochemistry as well as the magnetic properties of the complexes , the esr spectrum of complex 3 \n the shape and the feature of the obtained spectrum are consistent with the oh geometry around the metal ion . \n 1h2o ( 3 ) showed a broad symmetrical band centered on giso = 2.155 without resolved hyperfine structure . \n in particular , the absence of copper(ii ) hyperfine coupling is common in the solid state . also , the absence of the forbidden magnetic dipolar transition at half field ( ca . \n 1600 gauss ; g = 4.0 ) excluded the cu --- cu interaction and confirmed the mononuclearity of the complex . \n the mass spectrum of complex 3 , showed the molecular ion and the base peaks at m / e 495 and 45 confirming its formula weight ( fw = 498.1 ) . \n the tga data ( table 3 ) of the complexes showed good agreement with the results of elemental analysis . \n inspection of the data revealed the following remarks : ( i ) elimination of the solvated methanol / hydrated water molecules occurs in a separate step or overlapped with the removal of the coordinated ones . \n this stage is accompanied by a weak exothermic peak except complexes 3 and 4 which exhibited an endothermic peak . \n ( ii ) elimination of the coordinated water molecules for some complexes is accompanied by loss of hno3 , h2so4 , hbr or acoh acids via an exothermic or endothermic process depending on the nature of the complex and the removed acid . \n ( iii ) the tg - dsc thermogram of the perchlorato- complex ( 1 ) showed a sharp sudden inflection at 218c with a mass loss ; 94.13% via a very strong endothermic process ( h = 830.2 j / g ) ; a phenomenon related to clo4 complexes ( table 3 ) . \n metallic copper was obtained as the end product via further decomposition of cu2o into cu . \n the activation energy ( e * ) of decomposition of the complexes as well as the collision factor ( a ) were evaluated graphically using the coats- redfern equation ; ln[ln(1)t2]=e*rt+ln[are ] where is the fraction of sample decomposed at temperature t , is the heating rate and r is the gas constant . \n a plot of ln [ -ln ( 1 - )/tagainst 1/t gives a straight line whose slope = -e*/r and its intercept = ln [ ar/ e * ] . \n the activation entropy , enthalpy and free energy changes of the decomposition were calculated by the following equations : s*=2.303 r log(ah / kt ) , h*=e*rt and g*=h*ts * where h , k and t are the planck 's constant , boltzmann 's constant and the mid temperature in the tg thermogram , respectively . \n the evaluated kinetic and thermodynamic parameters of some complexes ( table 4 ) reflect the non spontaneity and the endothermicity of the decomposition stages as well as the orderness of the activated species . \n as shown from table 4 , h * has comparable positive values and ranges from 2.805 - 3.752 k j molfor the first stage . also , the values of a , e * , h * and g * increase for the subsequent degradation steps , revealing the high stability of the remaining part as well as the lower rate of the removal of the subsequent species than that of the precedent one . \n e * , h * and g * are in k j molwhile s * is in j molk . \n the solution was then neutralized with aqueous ammonia solution and the metal ions titrated with edta . \n thermal analyses ( tg - dsc ) were carried out on a shimadzu- 50 thermal analyzer in nitrogen atmosphere and a heating rate of 20c / min using the ta-50 ws1 program . \n esr spectra were recorded on a bruker elexsys , e 500 operated at x- band frequency . \n mass spectra were recorded either at 70 ev on a gas chromatographic gcmsqp 1000- ex shimadzu mass spectrometer . \n h nmr spectra were recorded as dmso- d6 solutions on a varian mercury vx- 300 nmr spectrometer using tms as an internal standard . \n molar conductivity was measured as dmf solutions on the corning conductivity meter ny 14831 model 441 . \n magnetic susceptibility of the complexes was measured at room temperature using a johnson matthey , mki magnetic susceptibility balance . \n an ethanolic mixture of 2-hydrazinyl-4,8-dimethyl quinoline ( 0.01 mol ) and 2,4-dihydroxybenzaldehyde ( 0.012 mol ) was refluxed for 1/2 h. the formed yellow compound was filtered off , washed with ethanol and crystallized from ethanol . \n the results of elemental analysis , % yield and m.pc are shown in table 1 . \n a methanolic solution of the metal salt was added gradually to a methanolic solution of the phenolic hydrazone ( h2l ) in the mole ratio 1 : 1 ; metal ion : ligand . \n then , the reaction mixture was refluxed for 2 - 6 h where the solid complexes were precipitated , filtered off , washed with methanol and finally diethyl ether and then dried in vacuo . in general , the obtained complexes ( table 1 ) are colored and quite stable in atmospheric conditions . also , most of the complexes have high melting points ( > 300 ) indicating their strong bonds . \n the complexes are insoluble in water and most common solvents ; but they are soluble in dmf and dmso solvents . \n the investigated hydrazone ; 4-[(2-(4,8-dimethylquinolin-2-yl)hydrazono)methyl ] benzene-1,3-diol ; ( h2l ) was prepared by a condensation reaction of 2-hydrazinyl-4,8-dimethylquinoline with 2,4-dihydroxybenzaldehyde . \n the results of elemental analysis ( table 1 ) are in good harmony with the proposed formula . the ir spectrum ( table 2 ) showed bands at 3426 , 3159 and 1603 cmassignable to (oh ) , (nh ) and (c = n ) ; respectively . on the other hand , the electronic absorption spectra of the hydrazone in dmf exhibit two intense bands at 266 and 320 nm characteristic for - * transitions of the aromatic and c = n group , respectively . \n in addition , the band at 371 nm referred to a charge transfer ( ct ) transition . \n the mass spectrum of the ligand showed the molecular ion and the base peaks at m / z = 307 and 172 confirming its formula weight ( fw = 307.35 ) . the mass fragmentation pattern ( scheme 1 ) supported the suggested structure of the ligand . \n also , the h nmr spectral data of the ligand in d6-dmso relative to tms ( figure 1 ) lend a further support of its structure . the signals due to oh and nh protons are disappeared upon deuteration . analytical and physical data of the copper(ii)- phenolic complexes . magnetic , conductivity , electronic and ir spectral data for the copper(ii)- phenolic complexes \n hnmr spectrum of the phenolic hydrazone ; = 7.05 - 7.73 for aromatic protons ( 7h ) . \n the interaction of the phenolic hydrazone ( h2l ) with several copper(ii)- salts afforded mono- and binuclear as well as dimeric complexes depending on the type of the anion ; scheme 2 . \n the dimeric ( 1 & 5 ) and the binuclear ( 2 ) complexes are formed via phenoxy bridging . in general , the isolated complexes reflect the strong coordinating power of the so4 , aco , br , cl and no3 anions relative to the non coordinating clo4 anion . \n also , they reflect a variety of modes of bonding as well as various geometries ( octahedral , square pyramid and square planar ) depending on the type of the counter anion ( scheme 2 ) . \n in addition , complexes ( 2 - 4 & 6 ) reveal the highest affinity of copper(ii)-ions for n - donors . for square pyramidal complexes ( 1,2 & 4 ) , \n structural elucidation of the isolated complexes was achieved via elemental and thermal analyses , magnetic susceptibility and conductivity measurements as well as spectral studies viz . electronic , vibration , mass and esr spectra . \n comparison of the ir bands of the free phenolic hydrazone ( h2l ) and its complexes revealed the following : ( i ) all complexes showed broad bands in the region 3423 - 3385 cmdue to oh stretches of either the phenolic or the associated water / methanol molecules . \n ( ii ) the strong band at 1603 cmassignable to (c = n ) stretch in the free ligand undergoes a shift to higher wave numbers ( 1641 - 1612 cm ) upon complexation , supporting the coordination of the hydrazone linkage to all metal ions . \n this can be explained on the basis of the diminished repulsion between the lone pairs of electrons of the two adjacent n atoms upon complexation and hence , - electron delocalization . \n ( iii ) the perchlorato and sulfato complexes ( 1 & 6 ) showed the (s - o ) or (cl - o ) stretches around 1100 cm . \n also , the nitrato complex ( 2 ) showed the (n - o ) stretch at 1394 cm . \n ( iv ) in the acetato complex ( 5 ) , the new band at 1635 cm ; (c = o ) , confirm the monodentate nature of the acetate ion . \n the molar conductance values ( table 2 ) of the current chelates in dmf ( 1.0 mmol / l ) revealed a non- electrolytic nature of all complexes except the perchlorato- complex ( 1 ) which showed molar conductance of 175 and ohmcmmolsuggesting its 1:2 electrolytic nature . \n the complex ( 1 ) has 3 mol ions / mol ( + 2 , -1 ) , one of which is bi- positive . in case of complexes 2 - 4 , \n the relatively high values of the molar conductance may be due to their partial dissociation in dmf solutions . \n however , they did not reach the previously reported values for 1:1 electrolytes in dmf solutions ( ~70 - 110 ohmcmmol ) . on the other hand , the copper(ii)- complexes ( 1 - 6 ) ; d - system exhibit eff values in the range 1.33 - 2.01 b.m . \n the subnormal eff values for complexes ( 1 , 2 & 5 ) indicate m--- minteractions in the solid state supporting either dimeric or binuclear nature of the complexes . \n solution electronic spectra of all phenolic complexes in dmf ( figure 2 & table 2 ) are more or less similar and show a series of bands within the range 269 - 352 nm due to different intra- ligand transitions . besides , the phenoxide to metal charge transfer band ( lmct transition ) appears in the range 371 - 381 nm . \n in addition , the copper ( ii)- complexes ( 1 - 6 ) display relatively less intense bands at 436 - 488 nm that arise from different d - d transitions of copper ( ii ) . the position and intensity of d - d bands suggest a distorted square planar , square pyramid or oh environment around copper ( ii)- ion . to obtain further information about the stereochemistry as well as the magnetic properties of the complexes , the esr spectrum of complex 3 \n the shape and the feature of the obtained spectrum are consistent with the oh geometry around the metal ion . the esr spectrum of [ cu(h2l)(h2o)2cl2 ] . \n 1h2o ( 3 ) showed a broad symmetrical band centered on giso = 2.155 without resolved hyperfine structure . \n in particular , the absence of copper(ii ) hyperfine coupling is common in the solid state . also , the absence of the forbidden magnetic dipolar transition at half field ( ca . \n 1600 gauss ; g = 4.0 ) excluded the cu --- cu interaction and confirmed the mononuclearity of the complex . \n the mass spectrum of complex 3 , showed the molecular ion and the base peaks at m / e 495 and 45 confirming its formula weight ( fw = 498.1 ) . \n the tga data ( table 3 ) of the complexes showed good agreement with the results of elemental analysis . \n inspection of the data revealed the following remarks : ( i ) elimination of the solvated methanol / hydrated water molecules occurs in a separate step or overlapped with the removal of the coordinated ones . \n this stage is accompanied by a weak exothermic peak except complexes 3 and 4 which exhibited an endothermic peak . \n ( ii ) elimination of the coordinated water molecules for some complexes is accompanied by loss of hno3 , h2so4 , hbr or acoh acids via an exothermic or endothermic process depending on the nature of the complex and the removed acid . \n ( iii ) the tg - dsc thermogram of the perchlorato- complex ( 1 ) showed a sharp sudden inflection at 218c with a mass loss ; 94.13% via a very strong endothermic process ( h = 830.2 j / g ) ; a phenomenon related to clo4 complexes ( table 3 ) . \n metallic copper was obtained as the end product via further decomposition of cu2o into cu . \n the activation energy ( e * ) of decomposition of the complexes as well as the collision factor ( a ) were evaluated graphically using the coats- redfern equation ; ln[ln(1)t2]=e*rt+ln[are ] where is the fraction of sample decomposed at temperature t , is the heating rate and r is the gas constant . a plot of ln [ -ln ( 1 - )/tagainst 1/t gives a straight line whose slope = -e*/r and its intercept = ln [ ar/ e * ] . \n the activation entropy , enthalpy and free energy changes of the decomposition were calculated by the following equations : s*=2.303 r log(ah / kt ) , h*=e*rt and g*=h*ts * where h , k and t are the planck 's constant , boltzmann 's constant and the mid temperature in the tg thermogram , respectively . \n the evaluated kinetic and thermodynamic parameters of some complexes ( table 4 ) reflect the non spontaneity and the endothermicity of the decomposition stages as well as the orderness of the activated species . \n as shown from table 4 , h * has comparable positive values and ranges from 2.805 - 3.752 k j molfor the first stage . also , the values of a , e * , h * and g * increase for the subsequent degradation steps , revealing the high stability of the remaining part as well as the lower rate of the removal of the subsequent species than that of the precedent one . \n e * , h * and g * are in k j molwhile s * is in j molk . \n the solution was then neutralized with aqueous ammonia solution and the metal ions titrated with edta . \n thermal analyses ( tg - dsc ) were carried out on a shimadzu- 50 thermal analyzer in nitrogen atmosphere and a heating rate of 20c / min using the ta-50 ws1 program . \n esr spectra were recorded on a bruker elexsys , e 500 operated at x- band frequency . \n mass spectra were recorded either at 70 ev on a gas chromatographic gcmsqp 1000- ex shimadzu mass spectrometer . \n h nmr spectra were recorded as dmso- d6 solutions on a varian mercury vx- 300 nmr spectrometer using tms as an internal standard . \n molar conductivity was measured as dmf solutions on the corning conductivity meter ny 14831 model 441 \n . magnetic susceptibility of the complexes was measured at room temperature using a johnson matthey , mki magnetic susceptibility balance . \n the solution was then neutralized with aqueous ammonia solution and the metal ions titrated with edta . \n thermal analyses ( tg - dsc ) were carried out on a shimadzu- 50 thermal analyzer in nitrogen atmosphere and a heating rate of 20c / min using the ta-50 ws1 program . \n esr spectra were recorded on a bruker elexsys , e 500 operated at x- band frequency . \n mass spectra were recorded either at 70 ev on a gas chromatographic gcmsqp 1000- ex shimadzu mass spectrometer . \n h nmr spectra were recorded as dmso- d6 solutions on a varian mercury vx- 300 nmr spectrometer using tms as an internal standard . \n molar conductivity was measured as dmf solutions on the corning conductivity meter ny 14831 model 441 \n . magnetic susceptibility of the complexes was measured at room temperature using a johnson matthey , mki magnetic susceptibility balance . \n an ethanolic mixture of 2-hydrazinyl-4,8-dimethyl quinoline ( 0.01 mol ) and 2,4-dihydroxybenzaldehyde ( 0.012 mol ) was refluxed for 1/2 h. the formed yellow compound was filtered off , washed with ethanol and crystallized from ethanol . \n the results of elemental analysis , % yield and m.pc are shown in table 1 . \n a methanolic solution of the metal salt was added gradually to a methanolic solution of the phenolic hydrazone ( h2l ) in the mole ratio 1 : 1 ; metal ion : ligand . \n then , the reaction mixture was refluxed for 2 - 6 h where the solid complexes were precipitated , filtered off , washed with methanol and finally diethyl ether and then dried in vacuo . in general , the obtained complexes ( table 1 ) are colored and quite stable in atmospheric conditions . \n also , most of the complexes have high melting points ( > 300 ) indicating their strong bonds . \n the complexes are insoluble in water and most common solvents ; but they are soluble in dmf and dmso solvents . \n the ligational behavior of the phenolic hydrazone ( h2l ) is highly affected by the type of the anion e.g. it behaves as a neutral nn bidentate donor in case of cl , br and so4anions ( mononuclear complexes 3 , 4 & 6 ) . also , it acts as a mono basic no donor with o- bridging in case of clo4and aco anions(dimeric complexes 1 & 5 ) . \n the isolated complexes reflect the strong coordinating power of the so4 , aco , br , cl and no3 anions . also , they reflect the structural diversity ( octahedral , square pyramid and square planar ) depending on the type of the counter anion ( scheme 2 ) . in general , \n square planar , square pyramid and octahedral complexes rather than tetrahedral complexes usually arise from strong field ligands , the stronger the ligand , the more favored is the trans isomer . also , the larger the size of the chelated ring ( 5- or 6- membered ) , the more favored is the trans arrangement ( dimeric complexes 1 & 5 ) . on the other hand , the binuclear complex 2 ( 2:3 ; \n m : l ) has two proposed structures on basis of the results of elemental analysis ( chn ) ; scheme 3 . \n however , the eff value ( table 2 ) suggests two adjacent copper(ii)- ions . also , the % metal ion content ( table 1 ) as well as the tg data ( table 3 ) are concordant with the binuclear structure ( 2a ) . from the interpretation of elemental and thermal analyses and spectral studies ( infrared , electronic , mass and esr ) as well as magnetic susceptibility and molar conductivity measurements , \n it is possible to draw up the proposed structures of the copper(ii)- complexes as shown in scheme 2 . \n \n gae and bae participated in the design of the study , analysis of the data and modification of the manuscript .", "role": "user" }, { "content": "backgroundthe heterocyclic hydrazones constitute an important class of biologically active drug molecules . \n the hydrazones have also been used as herbicides , insecticides , nematocides , redenticides , and plant growth regulators as well as plasticizers and stabilizers for polymers . \n the importance of the phenolic quinolyl hydrazones arises from incorporating the quinoline ring with the phenolic compound ; 2,4-dihydroxy benzaldehyde . \n quinoline ring has therapeutic and biological activities whereas , phenols have antiseptic and disinfectants activities and are used in the preparation of dyes , bakelite and drugs . \n the present study is planned to check the effect of the counter anions on the type and geometry of the isolated copper(ii)- complexes as well as the ligational behavior of the phenolic hydrazone ; 4-[(2-(4,8-dimethylquinolin-2-yl)hydrazono)methyl ] benzene-1,3-diol ; ( h2l).resultsa phenolic quinolyl hydrazone ( h2l ) was allowed to react with various copper(ii)- salts ( cl , br , no3 , clo4 , aco , so42- ) . \n the reactions afforded dimeric complexes ( clo4 , aco ) , a binuclear complex ( no3 ) and mononuclear complexes ( the others ; cl , br , so42- ) . \n the isolated copper(ii)- complexes have octahedral , square pyramid and square planar geometries . \n also , they reflect the strong coordinating ability of no3 , cl , br , aco and so42- anions . depending on the type of the anion \n , the ligand showed three different modes of bonding viz . \n ( nn)0 for the mononuclear complexes ( 3 , 4 , 6 ) , ( no)- with o- bridging for the dimeric complexes ( 1 , 5 ) and a mixed mode [ ( nn)0 + ( no)- with o- bridging ] for the binuclear nitrato- complex ( 2).conclusionthe ligational behavior of the phenolic hydrazone ( h2l ) is highly affected by the type of the anion . \n the isolated copper(ii)- complexes reflect the strong coordinating power of the so42- , aco , br , cl and no3 anions . also , they reflect the structural diversity ( octahedral , square pyramid and square planar ) depending on the type of the counter anion .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: fluoro - quinolones are one of the most common antibiotics used by clinicians all over the world . \n the most common adverse reactions of fluoro - quinolones involve the gi tract , with 3% to 17% of patients reporting mild nausea , vomiting , and/or abdominal discomfort . \n neuropsychiatric adverse effects are not uncommon . among them , mild headache and dizziness are the common adverse effects . rarely hallucinations and seizures have been reported . \n we report three cases with interesting and clinically significant presentation of acute anxiety and insomnia while treated with levofloxacin . \n he was prescribed levofloxacin 500 mg for 5 days , once daily in night . the first day he could not sleep throughout the night . \n he was able to sense the qualitative difference in the level of comfort in carrying out his daily routine . \n next day morning after consultation with his physician , he was prescribed a different class of antibiotic . the same day night \n he stopped levofloxacin , after which her neuropsychiatric symptoms remitted completely on the next day . mr . \n s , a 32-year - old doctor , medicated himself with levofloxacin 750 mg for his acute lower respiratory tract infection . \n he had taken complete courses of levofloxacin 500 mg for the same complaints in the past . \n this time he had samples of 750 mg tablets only and so he took it . within 4 to 6 h , \n the next day he consulted at psychiatry opd and was diagnosed to have acute nonspecific anxiety . \n the same day levofloxacin was stopped and his sleep and anxiety symptoms normalized from the next day . \n there was no relapse of anxiety symptoms in the next 6 months of follow up . \n none of them were willing to restart levofloxacin at any point of time due to their past dreadful experiences . \n he was prescribed levofloxacin 500 mg for 5 days , once daily in night . the first day he could not sleep throughout the night . \n he was able to sense the qualitative difference in the level of comfort in carrying out his daily routine . \n next day morning after consultation with his physician , he was prescribed a different class of antibiotic . the same day night \n mrs . s , a 30-year - old woman , developed lower respiratory tract illness . \n he stopped levofloxacin , after which her neuropsychiatric symptoms remitted completely on the next day . \n s , a 32-year - old doctor , medicated himself with levofloxacin 750 mg for his acute lower respiratory tract infection . he had taken complete courses of levofloxacin 500 mg for the same complaints in the past . \n this time he had samples of 750 mg tablets only and so he took it . within 4 to 6 h , \n the next day he consulted at psychiatry opd and was diagnosed to have acute nonspecific anxiety . \n the same day levofloxacin was stopped and his sleep and anxiety symptoms normalized from the next day . \n there was no relapse of anxiety symptoms in the next 6 months of follow up . \n none of them were willing to restart levofloxacin at any point of time due to their past dreadful experiences . \n effects within the central nervous system ( cns ) are generally some of the more frequent adverse consequences of quinolones therapy . \n one of the recent review on this subject had reported that mania , insomnia , acute psychosis and delirium were the most frequently reported psychiatric adverse events ; grand mal convulsion , confusional state and myoclonus were the most frequently reported neurological adverse events . \n ciprofloxacin , ofloxacin , and pefloxacin were the quinolones with more neurological and psychiatric adverse drug reactions reported in the literature . \n cns effects of quinolones correlate with its binding to the receptors for -amino butyric acid ( gaba ) in the brain . \n there are reports on quinolones directly activating n - methyl - d - aspartate ( nmda ) and adenosine receptors . \n thus , under specific conditions of sufficient cns penetration , associated with antagonism of inhibitory pathways ( gaba ) and stimulation of excitatory pathways ( nmda , adenosine ) , observable cns symptoms are manifested . \n this mechanism explains the pathogenesis of the acute anxiety and insomnia in the above cases with levofloxacin therapy . \n it is even possible that the above - said cases might have progressed on to psychosis , if the full course of levofloxacin therapy was completed . in multi - drug - resistant tuberculosis ( mdrtb ) , higher doses of levofloxacin are prescribed . in this scenario , \n the third case indicates a strong need for surveillance of neuropsychiatric symptoms in these patients . in the treatment of mdr - tb patients , \n the other agents like cycloserine are already an established risk factor for neuropsychiatric side effects . \n when levofloxacin is combined with them , it might have an additive effect on the above unpleasant symptoms . \n the other interesting thing to be noted from above 3 cases is that , they all were young adults and none of them had any cns - related disorders . \n this is important because the previous literature available on fluoroquinolones suggest that neuropsychiatric adverse effects are frequently noted in elderly and people with cns lesions . \n so by presenting the above three cases , we like to emphasize on the following points . \n physicians and psychiatrists should be aware of neuropsychiatric side effects of levofloxacin . \n although neuropsychiatric side effects of fluoroquinolones are more common in the elderly , they can also affect younger patients.stopping the drug in time may prevent the progress of nonspecific anxiety and insomnia to major psychiatric disorders like psychosis.although there are neuropsychiatric side effects mentioned as rare in the drug leaflet provided by the pharmaceutical companies , this case series and other reports from the literature indicate that neuropsychiatric side effects are relevant and require more systematic research on their prevalence.the research should also look whether there is a dose relation between levofloxacin and side - effects . \n this is specifically important in mdrtb where higher doses of levofloxacin are prescribed.there should also be a surveillance of the effect of combined prescriptions like nsaids , anti - histaminics , anti - tubercular drugs , etc with levofloxacin.cooperation of psychiatrists , pulmonologists , and general practitioners is required in further interdisciplinary research on neuropsychiatric side effects of levofloxacin and other fluoroquinolones . \n although neuropsychiatric side effects of fluoroquinolones are more common in the elderly , they can also affect younger patients . \n stopping the drug in time may prevent the progress of nonspecific anxiety and insomnia to major psychiatric disorders like psychosis . \n although there are neuropsychiatric side effects mentioned as rare in the drug leaflet provided by the pharmaceutical companies , this case series and other reports from the literature indicate that neuropsychiatric side effects are relevant and require more systematic research on their prevalence . \n the research should also look whether there is a dose relation between levofloxacin and side - effects . \n there should also be a surveillance of the effect of combined prescriptions like nsaids , anti - histaminics , anti - tubercular drugs , etc with levofloxacin . \n cooperation of psychiatrists , pulmonologists , and general practitioners is required in further interdisciplinary research on neuropsychiatric side effects of levofloxacin and other fluoroquinolones .", "role": "user" }, { "content": "fluoroquinolones can cause adverse neuropsychiatric side effects , which are more common in older age . \n we present three cases of levofloxacin - induced acute anxiety and insomnia in young adults . in all the cases , \n discontinuation of levofloxacin immediately lead to remission .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: whereas george wants to know whether he has the gene for the disease , francis prefers to live his life without knowing . \n the problem is that , if george decides to be tested and results positive , then this means that francis also has the gene \n . it would be difficult for george to keep the information from his father , so george s wish to know is in conflict with francis s wish not to know . \n does francis have a right not to know?1 if so , where does this right come from ? \n scenarios such as the conflict of interests between george and francis illustrate the potential impact that a right not to know could have on people s healthcare options , on their life projects , and even on their relationships with genetically related family members . that is why the choice not to know is so widely discussed in the philosophical literature , and a lively debate centres on whether such a choice should be safeguarded as a right ( see for instance , solbakk et al . \n the main justification for the right not to know is that one should be able to exercise at least some control over access to information about one s health conditions and prospects , and that one s desire not to know whether one will develop a certain condition should be respected . \n these considerations are usually grounded in the principle of respect for personal autonomy ( e.g. , andorno 2004 ; human genetics commission 2000 , p. 19 ) . \n but it has been argued that it is a mistake to defend the right not to know on the basis of personal autonomy , especially in the context of genetic testing . \n one argument is that the choice not to know can not always be justified on the basis of the principle of the autonomy of the individual , because the information obtained via genetic testing does not always belong to an individual alone . in the scenario \n above , we saw that if george had the gene for huntington disease , then francis would too . \n francis does not want to know whether he has the gene , but george does . \n when individuals have conflicting interests and preferences , and information disclosed to one can not be easily kept from the other , it is hard to respect the interests and preferences of both at once . \n genetic information is typically shared , and an examination of its characteristics may invite a revision of our ethical framework which is based on the autonomy of the person as a self - standing individual.genetics supports a relational understanding of the person and therefore that genetic ethics requires ethical models which respect both individuals and groups ( widdows 2009 , p. 173).another argument is that it is incoherent to justify the choice not to know on the basis of the principle of personal autonomy , because not knowing undermines the capacity to make autonomous choices . consider our initial scenario . \n george wants to know whether he has the gene for huntington disease , and if he obtains this knowledge , his future decisions will be informed by it . \n francis prefers not to know and , if he manages to remain in ignorance about the possibility of developing huntington disease , his future decisions will not be affected . \n according to the incoherence objection , george s and francis s individual preferences are not neutral with respect to autonomy : george does not compromise the autonomy of his future decision - making , whereas francis does . \n genetics supports a relational understanding of the person and therefore that genetic ethics requires ethical models which respect both individuals and groups ( widdows 2009 , p. 173 ) . \n different versions of this objection have been put forward ( see harris and keywood 2001 ; malpas 2005 ; rhodes 1998 ) . here \n are the key formulations:[w]e can not defend a right not to know our genetic information in the name of autonomy alone . \n autonomy [ ] demands that we exercise our capacity to reason and this surely entails the pursuit of pertinent genetic information not the rejection of it . \n ( malpas 2005)now if autonomy is the ground for my right to determine my own course , it can not also be the ground for not determining my own course . \n if autonomy determines my right to knowledge , it can not also justify my refusing to be informed . \n i may not be aware of the moral implications of ceding autonomy by insisting on genetic ignorance , but the ramifications are there , nevertheless . \n 18)[w]here i give someone ( against their will ) reliable information about themselves or their condition which is relevant to decisions they must make i may violate a liberty they assert but i do not violate their autonomy , for the information i give them is necessary for their autonomous decision making . ( \n harris and keywood 2001 , page 419 , my emphasis)in the rest of the paper i shall concentrate on the version of the incoherence objection put forward by john harris and kirsty keywood , according to which knowledge of genetic information is necessary to the capacity for autonomous decision - making . \n the objection thus formulated invites us to reflect not only on the legitimacy of the right not to know , but also on what is valuable in the making of autonomous choices . \n if we accept this version of the incoherence objection , then we also have to accept that the choice of genetic ignorance2 is a choice that undermines the autonomy of future choices , and in this respect it is comparable to letting other people shape one s life by selling oneself into slavery , or to taking drugs knowing that they will compromise one s capacity to make rational decisions . [ w]e can not defend a right not to know our genetic information in the name of autonomy alone . [ ] autonomy [ ] demands that we exercise our capacity to reason and this surely entails the pursuit of pertinent genetic information not the rejection of it . \n ( malpas 2005 ) now if autonomy is the ground for my right to determine my own course , it can not also be the ground for not determining my own course . \n if autonomy determines my right to knowledge , it can not also justify my refusing to be informed . \n i may not be aware of the moral implications of ceding autonomy by insisting on genetic ignorance , but the ramifications are there , nevertheless . \n ( rhodes 1998 , p. 18 ) [ w]here i give someone ( against their will ) reliable information about themselves or their condition which is relevant to decisions they must make i may violate a liberty they assert but i do not violate their autonomy , for the information i give them is necessary for their autonomous decision making . \n ( harris and keywood 2001 , page 419 , my emphasis ) contemporary studies in psychology and psychiatry support the general idea , frequently developed in leading philosophical theories of autonomy , that self - knowledge contributes to the exercise of personal autonomy in a way that promotes successful self - governance and well - being ( see for instance , wilson 2002 ) . \n but the claim that self - knowledge enhances the quality of one s autonomous choices is different from the claim that genetic information is necessary for autonomous decision making . \n first , it is not obvious that genetic information about oneself is the type of self - knowledge that contributes to the making of autonomous choices ; and second , the nature of the contribution of genetic information to autonomous decision - making needs to be reviewed . \n i offer some reasons to resist the claim that makes the incoherence objection plausible , but i shall not offer any defence of the legitimacy of the right not to know , as i share the view defended by widdows and by harris and keywood that one s choice not to know should not be made into a right which trumps other morally relevant considerations . in autonomy as self - authorship , i describe one central feature of the capacity for autonomous decision making , i.e. self - authorship . \n ( in my interpretation , this is also the feature harris and keywood emphasise when they talk about the value of autonomy . ) \n i suggest that self - authorship is not necessarily compromised by the choice of genetic ignorance . in \n not all knowledge about oneself is necessary to autonomy , i compare the acquisition of genetic information with another form of knowledge that can be similarly distressing or unsettling , at least in the short term . \n i argue that information about one s biases in deliberation necessarily contributes to self - authorship , whereas information resulting from genetic testing does not . \n my conclusion will be that choosing not to know information about oneself available through genetic testing is compatible with self - authorship , and \n what we mean by autonomy is crucial to the debate about the right not to know and its justification . for instance , matti hyry and tuija takala argue that the perceived conflict between exercising autonomy and the choice not to know is legitimate only if we intend autonomy as the entitlement and the obligation to decide in accordance to the best information available ( hyry and takala 2001 , page 411 ) . if information likely to be relevant to an agent s decisions is withheld , then the agent can not make fully informed decisions and autonomy is compromised . \n but if we mean something else by autonomy , for instance the entitlement to make decisions on whatever grounds the agent wishes , as long as she does not cause harm to others , then the choice not to know does not seem to conflict with the exercise of autonomy . \n i want to develop hyry and takala s insight that the notion of autonomy matters to an assessment of the incoherence objection . according to lay conceptions and recent philosophical accounts ( e.g. , frankfurt 1988 ; dworkin 1988 \n ; moran 2001 ; velleman 2006 ; mcleod 2002 ) , autonomous agents are able to shape their future , within constraints set by their own personal limitations and their physical and social environment . \n they do so by developing a life plan which reflects their beliefs , desires and values . in some sense , for autonomous agents \n the future is open and can be authored.the ability to choose our own life plan is arguably one of the essential conditions of the good life . what does this ability require ? \n people must have cognitive and emotional skills that make them able to ( a ) compare ( consciously or unconsciously ) different life plans , ( b ) select one among those life plans they are able to consider , ( c ) transform this choice into the intention to behave in accordance with the chosen plan and ( d ) transform this intention into behaviour that actually conforms to the chosen option . \n moreover , people must have skills that allow them to pursue different life plans with some definite chance of success , and they must be in a social context where these different life plans can actually be pursued . \n important aspect of this conception of autonomous agency is that people can become authors of their own life story , and this act of self - authorship is manifested ( among other things ) in the goals they set for themselves and in the choices they make . \n agents pursue those goals and make those choices that are important to the type of person they are or they want to become , and that are largely consistent with their beliefs , desires , and values . \n the ability to choose our own life plan is arguably one of the essential conditions of the good life . \n people must have cognitive and emotional skills that make them able to ( a ) compare ( consciously or unconsciously ) different life plans , ( b ) select one among those life plans they are able to consider , ( c ) transform this choice into the intention to behave in accordance with the chosen plan and ( d ) transform this intention into behaviour that actually conforms to the chosen option . \n moreover , people must have skills that allow them to pursue different life plans with some definite chance of success , and they must be in a social context where these different life plans can actually be pursued . \n ) this is also the aspect of autonomy that harris and keywood ( 2001 ) focus on when they attack the legitimacy of a right not to know . \n they write : the point of autonomy , the point of choosing and having the freedom to choose between competing conceptions of how , and indeed why , to live , is simply that it is only thus that our lives become in any real sense our own . \n and we do this , so far as this is possible at all , by shaping our lives for ourselves . \n our own choices , decisions and preferences help to make us what we are , for each helps us to confirm and modify our own character and enables us to develop and to understand ourselves . \n ( harris and keywood 2001 , p. 420).obviously , knowledge of different sorts informs the making of autonomous choices . in a successful life plan goals \n are truly valued by an agent and are achievable , having being selected on the basis of an agent s beliefs , desires and values , of her competencies and limitations , and of the relevant features of the surrounding physical and social environment . \n it is important for the agent to pursue her genuine interests and take into account existing constraints ( allport 1937 ; ford 1992 ; austin and vancouver 1996 ; armitage and christian 2004 ; kuhl and beckman 1985 ) . \n if the agent has a mistaken conception of what is important to her , she is likely to set for herself goals whose fulfilment will not make her happy . if she has an inflated conception of her own talents , she is likely to set for herself goals that are too ambitious , and this is likely to result in poor management of her resources and ultimately in failure and frustration . if other difficulties and potential obstacles are underestimated or ignored , the agent s life plan may turn out to be unrealistic and may need to undergo a number of revisions and adjustments , which come with considerable psychological costs . \n the point of autonomy , the point of choosing and having the freedom to choose between competing conceptions of how , and indeed why , to live , is simply that it is only thus that our lives become in any real sense our own . \n and we do this , so far as this is possible at all , by shaping our lives for ourselves . \n our own choices , decisions and preferences help to make us what we are , for each helps us to confirm and modify our own character and enables us to develop and to understand ourselves . \n information of the kind i have described certainly contributes to the making of rational life choices and to the fulfilment of one s life goals , but should it be regarded as necessary to the capacity for autonomous decision making and self - governance ? if an agent has an accurate understanding of her own potential and of the features of her environment that are relevant to the attainment of her goals , she will develop a life plan that is feasible and she will be more successful in pursuing her life goals . the aspirations of a woman who wishes to distinguish herself in the pursuit of science in a country where women are discouraged from going to university may be frustrated . \n similarly , a very talented musician who does not realise how severe his arthritis is becoming may find that his dream of making a living as a performing pianist will not come true . \n the point i want to press with these examples is that personal information and information about the surrounding environment impinge significantly on the feasibility of life plans and on the likelihood of success , but is not necessary to the capacity most human agents have to shape their own lives . failing to obtain such information does not rule out self - governance altogether . \n there are forms of knowledge that are necessary to self - authorship , and a good candidate is knowledge of one s own attitudes . consider the following case . \n gina learns that she suffers from a medical condition causing infertility , and this reduces the reproductive options readily available to her . \n she decides to start saving to be able to afford infertility treatment at a private clinic . \n knowledge of her medical condition and of the options available to her does affect her decisions , and allows her to adjust her life plan to the newly discovered constraints . \n however , even if gina had never discovered about her medical condition and its consequences , she would have preserved the capacity for rational decision making and self - governance . \n the difference would have been that her life plan would have had fewer chances to be fulfilled . \n whether she discovers or remains ignorant about her chances to reproduce naturally , gina engages in self - authorship by determining the best course of action given her attitudes and the constraints of the surrounding environment she is aware of . \n suppose gina has included motherhood in her life plan because , in the community where she lives , women of her age and status are expected to reproduce . if she examined her own beliefs , desires and values more closely , she would find that she does not have any strong desire to raise children , and that she is perfectly fulfilled by her successful career and her happy relationship with her husband . \n but people in her close social circle keep asking her why she does not want children , and she feels the pressure of their expectations . in this version of the scenario , gina \n the choice to become a mother is not one that is genuinely supported by her attitudes , and her life plan does not reflect her genuine inclinations . \n we could describe the case differently and say that external pressure has conditioned and moulded her personal preferences to the point that she acquired an aspiration that she did not have to start with . \n but even so , it is likely that her aspiration to become a mother badly coheres with some of her other aspirations , thereby creating tensions in her life project overall . in this case , \n partial ignorance of her mind and lack of awareness of the external factors affecting her attitudes undermine gina s claim to self - authorship . \n we need to ask now whether personal information obtained via genetic testing is the type of information that contributes to making more feasible life plans ( such as the information gina acquires about her infertility ) or the type of information without which self - authorship and self - governance are compromised ( such as gina s knowledge of her genuine attitude towards motherhood ) . \n harris and keywood argue for the latter option.[a]bsence of crucial information is inimical to self government , to the ability to control one s own destiny , and hence inimical to autonomy . \n ignorance of crucial information is inimical to autonomy in a way that other autonomy - limiting choices are not . for where the individual is ignorant of information that bears upon rational life choices she is not in a position to be self - governing . \n if i lack information , for example about how long my life is likely to continue i can not make rational plans for the rest of my life . if i do not know that my life is only likely to last five more years , rather than say twenty - five more , many of my priorities will be inappropriate and some will be self - defeating . ( harris and keywood 2001 , p. 421).i \n agree with the authors that there is absence of information which is inimical to self government , but i do not think that the absence of genetic information fits this description \n . why should an agent s ignorance of her life expectancy compromise her capacity for rational decision making or self - governance ? \n her decisions and plans can be rational given the knowledge at her disposal , which does not routinely include information about when exactly she will die . \n more generally , agents shape their lives and pursue their goals in absence of complete and accurate information about their future health prospects and to consider them lacking in self - governance because of their partial ignorance is raising the bar too high . \n [ a]bsence of crucial information is inimical to self government , to the ability to control one s own destiny , and hence inimical to autonomy . \n ignorance of crucial information is inimical to autonomy in a way that other autonomy - limiting choices are not . for where the individual is ignorant of information that bears upon rational life choices \n if i lack information , for example about how long my life is likely to continue i can not make rational plans for the rest of my life . \n if i do not know that my life is only likely to last five more years , rather than say twenty - five more , many of my priorities will be inappropriate and some will be self - defeating . \n it is plausible that the reason why francis does not want to know whether he has the gene for huntington disease is that he does not want some options to be ruled out in advance by that information . \n he does not want his long - term plans to be shaped by the lingering fear of developing the disease ( bortolotti and widdows 2011 ) . \n he welcomes the possibility of constructing his life plan in the light of information about his probable future state of health , and wants to start developing strategies that will help him face the difficulties ahead . \n this makes good sense , given that huntington disease in particular does impair one s capacity for rational decision making . \n gaining information about the likelihood of developing a debilitating condition such as huntington disease has an impact on the decisions an agent makes , as gina learning that she is not likely to reproduce naturally leads her to develop new strategies to achieve her goal of becoming a mother . \n however , choosing ignorance of genetic information does not necessarily make one s future choices less authentic or less genuinely authored \n those choices can still be in tune with one s beliefs , desires and values . rejecting genetic information ( when available ) does not necessarily compromise self - authorship , which is a core feature of the capacity for autonomous decision making ( or , as harris and keywood say , the point of autonomy \n information about whether francis and george have the gene for huntington disease is relevant to howopen their futures are and to whether they need to make contingency plans in order to achieve the goals they have set for themselves . \n francis and george preserve the capacity to shape their future by setting goals and making choices whether or not they decide to know about their likelihood to develop huntington disease . \n the fact that they make different choices about whether to acquire genetic information is a manifestation of their different ways to shape their own future . \n one might find francis s way objectionable on the grounds that it does not allow him to develop contingency plans , but it seems far too strong to regard his choice as irrational , which we would be tempted to do if we were to embrace the incoherence objection . \n i suggested that an agent s knowledge that she may develop a disease such as huntington does not impact on her capacity to write her own story , although it may contribute to changing the way in which the story is written . \n i also suggested there are forms of knowledge , that is , knowledge of the agent s own mind and her awareness of the external factors that influence her attitudes , which have a more central role to play in enabling the making of autonomous choices and can even be regarded as necessary conditions for self - authorship . \n reliable information about one s own attitudes ( beliefs , desires , values ) is not just conducive to choices that are genuinely authored , but seems to be necessary for self - authorship . \n one way in which the connection between self - knowledge and autonomy has been articulated in the recent philosophical and psychological literature is via the notion of self - narratives . \n agents integrate significant episodes of their lives into a coherent story , a self - narrative , and recognise themselves in the leading character of the story they tell . \n the narrative is not a mere description or interpretation of the leading character s attitudes and actions , but a way to impose coherence on life events , and to guide future behaviour on the basis of previously made commitments ( velleman 2006 ; mcadams 1997).one thing a deliberate decision accomplishes , when it creates an intention , is to establish a constraint by which other preferences and decisions are to be guided . \n ( frankfurt 1988 , page 175)some accounts of self - narratives focus on an individual conception of herself as an agent , but actual self - narratives are never developed in isolation from the social and physical environment in which the agent is embedded . \n social expectations and cultural influences are reflected in the stories agents tell , and even in the plot which is generally structured around initial goals , partial achievements and set - backs , and final success . \n stories are shaped not just by the agent s understanding of her own beliefs , desires and values , but also by her social roles and relationships . \n one thing a deliberate decision accomplishes , when it creates an intention , is to establish a constraint by which other preferences and decisions are to be guided . \n ( frankfurt 1988 , page 175 ) a claim that has received empirical support is that good self - narratives ( that is , narratives that represent more or less accurately key events in one s life and are largely coherent ) contribute to unified agency and psychological well - being . when self - narratives diverge widely from reality or reflect a fragmented set of attitudes , then it is difficult for the agent to coordinate with other agents , to engage effectively with the surrounding environment and to develop a unifying sense of self and purpose which supports long - term planning . \n the social environment to which the agent is connected provides a useful feedback mechanism on the development of the narrative , and the views of friends and family help the agent inhabit an inter - subjective space where her representation of reality is constrained not just by reality itself but also by other people s representations of it . \n people with psychiatric disorders in which autobiographical memories or salience mechanisms are disrupted have been described as unreliable autobiographers ( gerrans 2009 ) and their success in developing and pursuing life projects has been questioned ( bortolotti et al . \n correspondence between the self - narrative and significant life events prevents one from becoming isolated from one s social context and detached from the surrounding environment . \n reporting autobiographical facts inaccurately or unreliably does not yield cooperative communication and , as a result , alienates others \n . the person with a very idiosyncratic narrative may be avoided or ignored . moreover , the gap between the narrative and reality engenders failed predictions and unsuccessful explanations of personal events , which compromise autonomous decision making . in this framework , \n knowledge of the self matters to accurate and coherent narratives , and accurate and coherent narratives , in turn , matter to autonomous agency.3 important decisions about the agent s future are informed by her conception of her own attitudes and dispositions . by contributing to the construction of largely accurate and coherent self - narratives , knowledge of attitudes and dispositions becomes a core ingredient of self - authorship . \n circumstances that allow people to learn about themselves in a way that can then inform their future decisions by enhancing self - authorship enable the exercise of personal autonomy and thus should be actively promoted . \n one good example of such a circumstance is when , talking to a good friend or even noting the casual comment of a stranger , one discovers something about one s own attitudes or dispositions that one had not previously realised . \n when the new information brought to one s attention is not a desirable one , this process of self - revelation as wilson ( 2002 ) calls it may be upsetting at first , but is likely to have lasting benefits in the long run . \n typically self - revelation occurs when one acquires self - knowledge not by introspection but by inference from how one s behaviour is perceived or interpreted by others . as an extension of everyday forms of self - revelation \n , people can learn something new about themselves by participating in a psychological study ( bortolotti and mameli 2006 ) . \n it may have been distressing for research participants to learn that they had been willing to inflict pain on other human beings for the mere reason that they were told to do so by someone in an apparent position of authority this piece of information is likely to impact negatively on anybody s self - conception and self - esteem . yet , this insight into one s behavioural dispositions potentially allows one to exercise better control on one s future behaviour , as one is alerted to the fact that in certain situations one could easily be led to act against one s own values . \n similarly , in studies on how people make hiring decisions , research participants are likely to learn at debriefing that a variety of non - significant factors ( gender , ethnicity , overall appearance , and sexual preference ) impacted on how they assessed the performance of job candidates . \n for instance , it has been shown that , when qualifications and work experience are equivalent , overweight candidates are less likely to be selected , especially if they are female ( pingitore et al . \n learning that one is disposed to discriminate against people who are overweight may be unsettling at first , as agents normally represent themselves in a positive light and are resistant to acknowledging that their beliefs or actions may be prejudiced . \n however , information learnt during one s participation in a psychological study on prejudices in the job market can be taken into account when the next important hiring decision has to be made , to everybody s advantage . \n autonomy is promoted by letting agents make their own independent decisions , but also by ensuring agents have knowledge of the factors affecting their decisions ( bortolotti and mameli 2006 ) , especially when such factors can lead agents to make decisions that are not consistent with their explicit attitudes . in the case of psychological experiments where agents learn something new and important about the factors influencing their decisions \n , the acquired self - knowledge can have a negative effect on self - esteem , but can also contribute significantly to making agents better at decision making , thus directly affecting their capacity to make autonomous choices that are authentic . \n agents become aware of potential biases and have the opportunity to control the effects of such biases in future decisions . as a result , they can make decisions that are more attuned to their own beliefs , desires and values . is this form of self - knowledge , learning about one s behavioural dispositions via reliable testimony or by participating in a psychological study , analogous to learning the results of genetic testing with respect to its contribution to autonomous decision making ? \n but in both cases the distress seems to be short - lived ( elms 1982 ; kimmel 2001 ) . some research has been done on the psychological effects of genetic testing on people who are told that they may develop a disease such as breast cancer or huntington disease . \n predictably , people whose tests are positive tend to experience more distress than people whose tests are negative , but distress usually remains in the normal range and does not lead to either suicide or high levels of anxiety or depression ( marteau and croyle 1998 ; butow et al . \n when anxiety does increase as a result of the newly acquired information , this is usually only in the period immediately following the disclosure of the information ( lerman et al . \n one interesting result is that for some people knowing ( even in case of positive results ) turns out to be less distressing than living in uncertainty . in terms of psychological effects then , both coming to know about one s biases in decision making and acquiring genetic information about oneself are potentially distressing , but have not been shown to be likely causes of severe anxiety or long - term depression . \n in general terms , both types of information have benefits . acquiring genetic information , as harris and keywood emphasise and as i have already suggested , may allow an agent to revise and update her life plan and account for previously unforeseen contingencies ( e.g. shorter life expectancy or declining cognitive capacities ) . \n but the acquisition of genetic information is unlikely to have the same type of authorship - enabling effects on decision making that knowledge of one s biases in deliberation does have . \n knowledge that one s judgement can be skewed or distorted by biases or prejudices that are not immediately accessible to introspection allows one to control the often hidden factors influencing one s choices , and make choices that are better aligned with one s attitudes . in other words , it prevents agents from making decisions ( e.g. hiring a less qualified candidate because of gender biases ) that would not be supported by , and would clash with , their own attitudes . choosing genetic ignorance is not on a par with choosing to be sold into slavery or choosing to take drugs that compromise future decision making . \n this is because the acquisition of genetic information does not seem to play a significant role in helping agents to align their goals and their decisions with their attitudes . \n as previously suggested , the acquisition of genetic information may have implications for how open one s future turns out to be . \n such knowledge can inform the provision of contingency plans , and thus allow agents to continue to pursue their life projects when unforeseen difficulties and new constraints emerge ; but it is not a necessary ingredient of self - authorship . if this analysis is correct , and choosing genetic ignorance has no detrimental effect on autonomy as self - authorship , then it is not clear why it should be incoherent to appeal to autonomy in order to turn the choice not to know into a right . \n moreover , arguments like the incoherence objection may have other undesirable consequences . they draw too much attention to genetic information at the expense of other forms of personal information that have the potential to make a greater contribution to self - authorship . and \n they could also blind us to individual differences in the way in which agents choose to manage the uncertainty that their future inevitably brings . \n that said , we need to acknowledge that the acquisition of personal information obtained via genetic testing is valuable even if it turns out not to be necessary for autonomous decision making . \n one of the reasons why such knowledge is indeed valuable lies in the importance of contingency planning . \n knowledge of forthcoming adversities may not be necessary for autonomous decision making , but can help agents develop effective responses to such adversities and adjust their life plans accordingly . \n this requires resilience and creativity that are key and valuable features of human agency ( carel 2009 ; bortolotti 2010 ) . \n in this paper i discussed the incoherence objection which claims that the right not to know in the context of genetic information should not be grounded in autonomy because choosing not to know compromises autonomous decision making . \n i focused on one core aspect of autonomous decision making , what i called self - authorship. agents can shape their own future by setting goals and making choices that fit their attitudes and thus become the people they want to be . \n i argued that choosing genetic ignorance does not necessarily prevent agents from exercising self - authorship .", "role": "user" }, { "content": "the right not to know is often defended on the basis of the principle of respect for personal autonomy . if i choose not to acquire personal information that impacts on my future prospects , such a choice should be respected , because i should be able to decide whether to access information about myself and how to use it . \n but , according to the incoherence objection to the right not to know in the context of genetic testing , the choice not to acquire genetic information undermines the capacity for autonomous decision making . \n the claim is that it is incoherent to defend a choice that is inimical to autonomy by appealing to autonomy . in this paper , \n i suggest that the choice not to know in the context of genetic testing does not undermine self - authorship , which is a key aspect of autonomous decision making . in the light of this \n , the incoherence objection to the right not to know seems less compelling .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: dibromodimethylhydantoin ( dbdmh , 85.8 mg , 0.30 mmol ) was added to a 0.02 m solution of the aromatic amide 4 ( 66.9 mg , 0.20 mmol ) and catalyst 1 ( 11.5 mg , 0.02 mmol ) in chcl3 ( 10 ml ) at various temperatures ( 0 c , 40 c , or 55 \n the reaction was then quenched with a 1.5 m solution of butyl vinyl ether in methanol ( meoh , 0.5 ml ) . \n the time of quench was recorded for amide equilibration calculations and defined as time zero ( see supplementary information section viii ) . \n for ease of chiral hplc development , the phenol was subsequently protected as the methyl ether . \n the reaction was allowed to warm to room temperature and additional methanol was added ( 2.0 ml , ~5:1 by volume ch2cl2:meoh ) followed by 2.0 m trimethylsilyldiazomethane in hexanes ( 0.4 ml ) . \n the methylation was quenched with silica gel upon completion ( 15 - 30 min ) , filtered , and concentrated under reduced pressure . \n flash chromatrography of the crude residue with hexanes / etoac afforded products ( as a cis / trans mixture or independently isolated isomers ) . \n this material ( 5-me ) was dissolved in a 10% isopropanol / hexanes mixture ( 0.1 m ) and allowed to equilibrate , in solution , at room temperature over a prolonged time course to determine the experimental barriers to amide isomerization . \n barriers to racemization of 5-me were determined experimentally by heating in toluene at 70 c ( 0.6 m ) . \n isomeric ratios were determined by chiral hplc utilizing a chiralcel od - h column , with a flow rate of 0.75 ml / min , in 95:5 hexanes : ethanol : rt(t , trans ) = 14.0 min , rt(s , trans ) = 15.3 min , rt(s , cis ) = 20.6 min , rt(r , cis ) = 23.9 min . \n ", "role": "user" }, { "content": "perhaps the most well - recognized stereogenic elements within chiral molecules are sp3-hybridized carbon atoms possessing four different substituents . however \n , axes of chirality may also exist about bonds with hindered barriers of rotation , leading to stereoisomers known as atropisomers.1 understanding the dynamics of these systems can be useful , for example , in the design of single - atropisomer drugs2 or molecular switches and motors.3 for molecules that exhibit a single axis of chirality , rotation about that axis leads to racemization as the system reaches equilibrium . \n we report here a two - axis system in which an enantioselective reaction that produces four stereoisomers ( two enantiomeric pairs ) displays a more complex scenario . following a catalytic asymmetric transformation , \n we observe a kinetically controlled product distribution that is substantially perturbed from the system s equilibrium position . \n notably , as the system undergoes isomerization , one of the diastereomeric pairs is observed to drift spontaneously to a higher enantiomeric ratio . in a compensatory manner \n , the other diastereomeric pair also converts to an altered enantiomeric ratio , reduced in magnitude from the initial ratio . \n these observations occur within a class of unsymmetrical amides that exhibits two asymmetric axes one defined through a benzamide substructure , and the other implicit with differentially n , n - disubstituted amides . \n the stereodynamics of these substrates provide an opportunity to observe a curious interplay of kinetics and thermodynamics intrinsic to a system of stereoisomers that is constrained to a situation of partial equilibration .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: it is widely accepted that biomedical data should be machine - readable and web - accessible . relational database management systems ( rdbms ) \n have proven highly effective with sequence data that are string - based , invariant in organization and interpretable without knowledge of the experiments , instruments or algorithms used to gather them . \n it has proven more difficult to manage data arising from complex biochemical measurements , imaging , flow cytometry and phenotypic assays of cells and tissues . \n the interpretation of these data , which are often unstructured ( e.g. , images ) , is critically dependent on experimental context , and this context changes frequently . \n the difficulty in developing satisfactory database solutions for high - content data is widely ascribed to insufficient standardization or poor implementation , but we believe the problem is more fundamental : it reflects the impossibility of fully specifying a priori complex experimental designs . flexible and creative design is the essence of good experimental science , and since design determines data structure ( the number of time points , repeats , conditions , etc . ) , structures frequently change ( fig . \n to accommodate these changes , database schema must be reconfigured frequently , a complex and time - consuming task . \n thus , most experimental data reside in unlinked , loosely annotated spreadsheets that are easily fragmented or lost . \n when data scope and complexity demand a more capable repository , a new database is often created ad hoc . as an illustrative problem in biological data management \n one is the sheer size of the data , which can exceed many terabytes per month . \n the second involves the difficulties of working with numerical data extracted by image analysis , which can include a large number of data types that have complex relationships to each other ( e.g. , the boundaries and intensities of cells or compartments and computed features such as nuclear translocation ; fig . \n for example , a typical genome - wide rnai screen might generate ~7 10 images ( ~1.3 terabytes of data ) ; analysis would increase the size only modestly ( by ~100 megabytes ) , but the number of data entries would increase from ~10 images to > 10 features ( supplementary fig . \n perform poorly with 10 data entities , and relational databases impose the organizational costs described above . in this paper \n we propose a potential solution to the challenge of managing high - dimensionality biomedical data based on the use of semantically - typed data hypercubes ( sdcubes ) in which binary data are stored in hierarchical data format 5 ( hdf5 ; http://www.hdfgroup.org/hdf5/ ) and metadata and data ontologies are stored in extensible markup language ( xml ; http://www.w3.org/standards/xml ) . \n we have created a new open - source java library , the sdcube programming library ( supplementary software 1 , http://www.semanticbiology.com/software/sdcube ) that can create sdcubes with appropriate dimensionality , encode the data model in a machine - readable xml ontology , and reformat sdcubes as needed when experiments change ( fig . \n to illustrate the use of sdcubes , we have created a second program imagerail ( supplementary software 2 , http://www.semanticbiology.com/software/imagerail ) for high - content microscopy that ( i ) segments images of cells grown in 96- and 384-well plates to extract features such as cell shape or nuclear fluorescence , ( ii ) stores experimental metadata and results of image analysis in sdcubes , ( iii ) computes sets of cellular features from the image ( e.g. , fluorescence and localization metrics ) , and ( iv ) displays metadata , images and analysis in various formats . by using sdcubes , imagerail is able to organize data according to the design of an experiment and its day - to - day evolution rather than an inflexible , predetermined schema . \n we use these tools to characterize the responses of tumor cells to therapeutic small molecules and show that the apparent ic50 for receptor inhibitors varies with ligand dose , that cell - to - cell variability is maximal as ligands and drugs approach concentrations likely to be encountered in vivo , and that variance impacts the shape of dose - response curves . \n our results suggest that monitoring variance will be broadly useful in pre - clinical pharmacology . moreover , because flow cytometry and multiplex biochemistry have similar workflows to imaging , imagerail and the sdcube programming library represent starting points for managing diverse experimental data . \n hdf5 files can contain both structured and unstructured data , can encode data hierarchically using groups \n ( analogous to file system folders ) , are unlimited in size and can be opened progressively using software libraries that read and write selected slices of data . \n the latter feature is critical for files that exceed the size of physical memory . to date \n , hdf5 has been used primarily ( if not exclusively ) in observational sciences ( particularly remote earth - sensing ) involving highly standardized data collection and little or no directed perturbation of the system under study . \n it has been suggested that hdf5 might be applied to biological imaging , but no practical implementations exist and hdf5 alone appears to be insufficient to meet the challenges of biological experiments involving complex perturbations such as gene knockdown , drug and ligand dose - response , pulse - chase , etc . \n sdcubes address this challenge by encoding the design of perturbation - rich experiments in xml and using the design to create hdf5 files of appropriate dimensionality . \n a two - format solution is needed because xml is ill - suited for storage of large numerical datasets and hdf5 lacks easy integration with \n minimum information standards such as minimum information for biological and biomedical investigations ( mibbi ) and other web - based ontologies . \n the hdf5 component of an sdcube is composed of basic data modules , each of which contains the hdf5 groups data , meta , raw and children ( fig . \n data contains measured or computed data stored in n - dimensional arrays ; meta contains metadata such as plate address , sample identifiers and the sdcube xml file ; and raw contains original csv , tiff , fcs and other primary data as byte arrays . \n the children group allows creation of nested data modules , each containing progressively more detailed information ( fig . \n the top - level children group is special in that it is always organized by \n sample , a label identical to experiment in the minimum information about a cellular assay ( miaca ) standard . \n the xml component of sdcubes contains four types of information : ( i ) standard metadata ( e.g. , investigator and research group ) ; ( ii ) experimental protocol ( e.g. , information on cell lines and reagents , in formats conforming to mibbi standards when possible ) ; ( iii ) experimental design ( e.g. , species and other variables in the protocol , such as time or perturbation , that are applicable to each sample ) ; and ( iv ) the identities of algorithms and free parameters used during conversion of raw data into useful experimental measurements ( see methods for details ) . \n using methods in the sdcube programming library ( supplementary note 1 ) , new samples , dimensions or assays can be appended to or inserted into an existing sdcube simply by modifying the xml file and adding to the children group at the top level of the hdf5 hierarchy ( fig . \n 2 ) and can combined to aggregate data from other sdcubes or divided up to create subsets of the data .. imagerail is a standalone program for high - throughput image analysis that creates and manipulates sdcubes and serves as a test of the concepts outlined above . imagerail has four software components . \n first , formatting tools create and modify sdcubes so that the children group is formatted to create a five - level data hierarchy comprising project , plate , well , ( image ) field and cell and ( cellular ) compartment ( conforming to the entity - relationship model in fig . \n 1b and 2e ) . drop - down lists and a gui for highlighting wells make it possible to specify which experimental conditions map to which wells , thereby specifying the experimental design and sdcube dimensionality and creating xml annotation ( fig . \n second , image analysis tools create and store segmentation masks based on standard algorithms for cell monolayers , which can be extended using existing software such as imagej ( fig . \n 3b ) . third , data viewers display raw data and computed features as images , line plots , histograms , scatter plots and multi - well plate views . scatter plotting includes multi - dimensional gating similar to that used for analysis of flow cytometry data ( fig . \n 3c ) . finally , embedded routines enable dynamic linking of data points to specific image features . \n dynamic linking allows users to highlight cells in an image that correspond to selected data points in a scatter plot ( fig . 3b and fig . \n 3c ) , facilitating the identification of outliers and experimental artifacts such as bubbles , tissue culture debris or edge effects ( supplementary fig . \n users choose the level of detail at which to store the link between segmentation and data ; at one extreme , pixel - by - pixel information can be stored , but we generally find it more useful to store either the centroid of each cell or a bounding box ( fig . \n 3d ) . although the sdcube data group raw can store image data , we are in the process of integrating imagerail with the open microscopy environment remote objects ( omero ) image server . \n omero provides powerful tools for processing and organizes images , is used widely in open - source and commercial image management applications and ome - tiff has found wide acceptance as a file standard for biological microscopy . \n it is widely hypothesized that variability in cellular responses to drugs and the presence of drug - resistant cell subpopulations can impact cancer therapy . \n one application of imagerail is to systematize single cell drug - response studies and uncover the origins and significance of variability . \n our proof - of - principle studies focused on the impact of changes in the concentration of epidermal growth factor ( egf ) on the ic50 of atp - competitive egf receptor ( egfr ) inhibitors erlotinib and gefitinib . \n we assayed inhibition by immunofluorescence microscopy , using antibodies specific for the pt202/py204-modified form of the downstream kinase erk1/2 ( henceforth pperk ) . \n egfr mutation and over - expression are implicated in a wide range of tumors , and erlotinib and gefitinib are used clinically to treat lung , colorectal and other cancers . here , we exposed cells to egf at 10 doses over a 10 range in combination with gefitinib at 8 doses over a 10 range using a simple adaptive design in which each 96-well plate was subjected to a different and changeable set of treatments and measurements . to enable image segmentation with a standard watershed algorithm , we treated cells with nuclear and cytoplasmic stains ( supplementary fig . \n the dataset comprised 160 conditions , 1.410 individual cells and an sdcube with 2.810 entries ( data are available in the supplemental materials in sdcube and csv formats ; a 10-fold larger dataset involving more proteins is shown in supplementary fig . \n , we can view data as a series of ic50 curves at differing egf concentrations ( [ egf ] ) , or as a set of egf dose - response curves at different drug concentrations ( [ drug ] ) ; cell - to - cell variability can also be visualized at any point ( fig . \n we observed that average levels of pperk increased with [ egf ] and decreased with [ gefitinib ] , and that the apparent ic50 was sensitive to egf concentration , varying ~20-fold as exogenous egf varied from 0 to 100 ng / ml ( fig . \n well - average data computed from images closely matched dose - response data obtained using conventional biochemical assays ( supplementary fig . \n the relationship between ic50 and [ egf ] varied substantially with cell type ( fig . \n 4c ) : whereas ic50 was strongly sensitive to [ egf ] in skbr3 and t47d cells , it was less so in mcf7 cells ( supplementary fig . 7 ) . \n data exploration of this type is intuitively simple , but involves the manipulation of many data entries ; because hdf5 successively loads data , there is no limit a priori to the number of entries , and imagerail has been validated with ~1010 data points . on comparing mean pperk levels with cell - to - cell variance using plate maps ( fig . \n 5a ) , we observed maximum variability at physiologically relevant doses of drug and ligand ( estimated to be 0.11.5 ng / ml for egf and 0.450 m for gefitinib ) . \n mean value and variance in response changed over time , such that 20 hours post - egf / gefitinib treatment , ic50 was less dependent on [ egf ] but the variance increased . by linking back to the underlying images , we observed that even in cells exposed to saturating doses of gefitinib ( 10 m ) for 20 hr , a subpopulation of cells ( ~1% ) exhibited elevated pperk levels . \n this implies not only that these cells were drug - resistant but also that erk signaling could be sustained in the absence of exogenous ligand ( a behavior different from that of cells that are simply gefitinib - insensitive ; fig . \n thus , single - cell data revealed three interesting features of cellular responses to gefitinib and egf . \n first , ic50 varied with the concentration of extracellular ligand , particularly at early time points . \n second , the extent of cell - to - cell variability was maximal near intermediate , physiologically - relevant concentrations ; conversely , it was masked when drug or ligand were added at high levels . \n third , cell - to - cell heterogeneity changed over time , being dominated initially by broad distributions and subsequently by rare cells with sustained signaling . \n whether the differences we observe are genetic , epigenetic or stochastic in origin is not yet clear , but reversibility implies that some are indeed stochastic , as we have previously demonstrated for tnf - responsive apoptosis - inducing ligand ( trail ) . \n the shape of dose - response curves for drugs and ligands often depends on the agent and cell type ( fig . 4c and supplementary \n gefitinib dose - response of cells exposed to egf conformed to a sigmoidal shape as expected for simple ligand - receptor binding ; however , the dose - response for an inhibitor of mek kinase ( pd0325901 ) , an enzyme lying immediately upstream of erk1/2 kinases in egfr signaling , was nearly linear over a 10 egf range ( fig . \n responses to gefitinib were bimodal , with low pperk levels in some cells and 100-fold higher levels in other cells ( fig . \n 5d ) but responses to pd0325901 were continuous with cells exhibiting a wide range of activities . we conclude that the mean - value dose - response curves for pd0325901 and gefitinib differed in shape because of variability at the single cell level , and speculate that this might be a general explanation for non - sigmoidal dose - response relationships . \n hdf5 files can contain both structured and unstructured data , can encode data hierarchically using groups \n ( analogous to file system folders ) , are unlimited in size and can be opened progressively using software libraries that read and write selected slices of data . \n the latter feature is critical for files that exceed the size of physical memory . to date \n , hdf5 has been used primarily ( if not exclusively ) in observational sciences ( particularly remote earth - sensing ) involving highly standardized data collection and little or no directed perturbation of the system under study . \n it has been suggested that hdf5 might be applied to biological imaging , but no practical implementations exist and hdf5 alone appears to be insufficient to meet the challenges of biological experiments involving complex perturbations such as gene knockdown , drug and ligand dose - response , pulse - chase , etc . \n sdcubes address this challenge by encoding the design of perturbation - rich experiments in xml and using the design to create hdf5 files of appropriate dimensionality . \n a two - format solution is needed because xml is ill - suited for storage of large numerical datasets and hdf5 lacks easy integration with \n minimum information standards such as minimum information for biological and biomedical investigations ( mibbi ) and other web - based ontologies . \n the hdf5 component of an sdcube is composed of basic data modules , each of which contains the hdf5 groups data , meta , raw and children ( fig . \n data contains measured or computed data stored in n - dimensional arrays ; meta contains metadata such as plate address , sample identifiers and the sdcube xml file ; and raw contains original csv , tiff , fcs and other primary data as byte arrays . \n the children group allows creation of nested data modules , each containing progressively more detailed information ( fig . \n the top - level children group is special in that it is always organized by \n sample , a label identical to experiment in the minimum information about a cellular assay ( miaca ) standard . \n the xml component of sdcubes contains four types of information : ( i ) standard metadata ( e.g. , investigator and research group ) ; ( ii ) experimental protocol ( e.g. , information on cell lines and reagents , in formats conforming to mibbi standards when possible ) ; ( iii ) experimental design ( e.g. , species and other variables in the protocol , such as time or perturbation , that are applicable to each sample ) ; and ( iv ) the identities of algorithms and free parameters used during conversion of raw data into useful experimental measurements ( see methods for details ) . \n using methods in the sdcube programming library ( supplementary note 1 ) , new samples , dimensions or assays can be appended to or inserted into an existing sdcube simply by modifying the xml file and adding to the children group at the top level of the hdf5 hierarchy ( fig . \n 2 ) and can combined to aggregate data from other sdcubes or divided up to create subsets of the data .. \n imagerail is a standalone program for high - throughput image analysis that creates and manipulates sdcubes and serves as a test of the concepts outlined above . \n first , formatting tools create and modify sdcubes so that the children group is formatted to create a five - level data hierarchy comprising project , plate , well , ( image ) field and cell and ( cellular ) compartment ( conforming to the entity - relationship model in fig . 1b and 2e ) . \n drop - down lists and a gui for highlighting wells make it possible to specify which experimental conditions map to which wells , thereby specifying the experimental design and sdcube dimensionality and creating xml annotation ( fig . \n second , image analysis tools create and store segmentation masks based on standard algorithms for cell monolayers , which can be extended using existing software such as imagej ( fig . \n 3b ) . third , data viewers display raw data and computed features as images , line plots , histograms , scatter plots and multi - well plate views . \n scatter plotting includes multi - dimensional gating similar to that used for analysis of flow cytometry data ( fig . \n dynamic linking allows users to highlight cells in an image that correspond to selected data points in a scatter plot ( fig . 3b and fig . \n 3c ) , facilitating the identification of outliers and experimental artifacts such as bubbles , tissue culture debris or edge effects ( supplementary fig . \n users choose the level of detail at which to store the link between segmentation and data ; at one extreme , pixel - by - pixel information can be stored , but we generally find it more useful to store either the centroid of each cell or a bounding box ( fig . \n although the sdcube data group raw can store image data , we are in the process of integrating imagerail with the open microscopy environment remote objects ( omero ) image server . \n omero provides powerful tools for processing and organizes images , is used widely in open - source and commercial image management applications and ome - tiff has found wide acceptance as a file standard for biological microscopy . \n it is widely hypothesized that variability in cellular responses to drugs and the presence of drug - resistant cell subpopulations can impact cancer therapy . \n one application of imagerail is to systematize single cell drug - response studies and uncover the origins and significance of variability . \n our proof - of - principle studies focused on the impact of changes in the concentration of epidermal growth factor ( egf ) on the ic50 of atp - competitive egf receptor ( egfr ) inhibitors erlotinib and gefitinib . \n we assayed inhibition by immunofluorescence microscopy , using antibodies specific for the pt202/py204-modified form of the downstream kinase erk1/2 ( henceforth pperk ) . \n egfr mutation and over - expression are implicated in a wide range of tumors , and erlotinib and gefitinib are used clinically to treat lung , colorectal and other cancers . here , we exposed cells to egf at 10 doses over a 10 range in combination with gefitinib at 8 doses over a 10 range using a simple adaptive design in which each 96-well plate was subjected to a different and changeable set of treatments and measurements . to enable image segmentation with a standard watershed algorithm , we treated cells with nuclear and cytoplasmic stains ( supplementary fig . \n the dataset comprised 160 conditions , 1.410 individual cells and an sdcube with 2.810 entries ( data are available in the supplemental materials in sdcube and csv formats ; a 10-fold larger dataset involving more proteins is shown in supplementary fig . \n , we can view data as a series of ic50 curves at differing egf concentrations ( [ egf ] ) , or as a set of egf dose - response curves at different drug concentrations ( [ drug ] ) ; cell - to - cell variability can also be visualized at any point ( fig . \n we observed that average levels of pperk increased with [ egf ] and decreased with [ gefitinib ] , and that the apparent ic50 was sensitive to egf concentration , varying ~20-fold as exogenous egf varied from 0 to 100 ng / ml ( fig . \n well - average data computed from images closely matched dose - response data obtained using conventional biochemical assays ( supplementary fig . \n the relationship between ic50 and [ egf ] varied substantially with cell type ( fig . \n 4c ) : whereas ic50 was strongly sensitive to [ egf ] in skbr3 and t47d cells , it was less so in mcf7 cells ( supplementary fig . 7 ) . \n data exploration of this type is intuitively simple , but involves the manipulation of many data entries ; because hdf5 successively loads data , there is no limit a priori to the number of entries , and imagerail has been validated with ~1010 data points . on comparing mean pperk levels with cell - to - cell variance using plate maps ( fig . \n 5a ) , we observed maximum variability at physiologically relevant doses of drug and ligand ( estimated to be 0.11.5 ng / ml for egf and 0.450 m for gefitinib ) . \n mean value and variance in response changed over time , such that 20 hours post - egf / gefitinib treatment , ic50 was less dependent on [ egf ] but the variance increased . by linking back to the underlying images \n , we observed that even in cells exposed to saturating doses of gefitinib ( 10 m ) for 20 hr , a subpopulation of cells ( ~1% ) exhibited elevated pperk levels . \n this implies not only that these cells were drug - resistant but also that erk signaling could be sustained in the absence of exogenous ligand ( a behavior different from that of cells that are simply gefitinib - insensitive ; fig . 5a and fig . \n thus , single - cell data revealed three interesting features of cellular responses to gefitinib and egf . \n first , ic50 varied with the concentration of extracellular ligand , particularly at early time points . \n second , the extent of cell - to - cell variability was maximal near intermediate , physiologically - relevant concentrations ; conversely , it was masked when drug or ligand were added at high levels . \n third , cell - to - cell heterogeneity changed over time , being dominated initially by broad distributions and subsequently by rare cells with sustained signaling . whether the differences we observe are genetic , epigenetic or stochastic in origin is not yet clear , but reversibility implies that some are indeed stochastic , as we have previously demonstrated for tnf - responsive apoptosis - inducing ligand ( trail ) . \n the shape of dose - response curves for drugs and ligands often depends on the agent and cell type ( fig . \n gefitinib dose - response of cells exposed to egf conformed to a sigmoidal shape as expected for simple ligand - receptor binding ; however , the dose - response for an inhibitor of mek kinase ( pd0325901 ) , an enzyme lying immediately upstream of erk1/2 kinases in egfr signaling , was nearly linear over a 10 egf range ( fig . \n responses to gefitinib were bimodal , with low pperk levels in some cells and 100-fold higher levels in other cells ( fig . \n 5d ) but responses to pd0325901 were continuous with cells exhibiting a wide range of activities . we conclude that the mean - value dose - response curves for pd0325901 and gefitinib differed in shape because of variability at the single cell level , and speculate that this might be a general explanation for non - sigmoidal dose - response relationships . \n by creating a lightweight data repository customized to the design of a specific experiment and then storing the design in a machine - readable xml format , the sdcube programming library places experimental design foremost in organizing data for storage . \n the use of xml to encode ontologies simplifies harmonization with existing web - based standards , and the use of hdf5 allows progressive access to even very large files . as the design changes or expands , the dimensionality of sdcubes changes as do the metadata tags that point to specific data elements . \n the result is an approach to data and metadata storage that aim to addresses the competing demands of data integrity and flexibility . \n little attention has been paid to computer - readable experimental designs , and only one public specification exists ( minimum information for data analysis in systems biology ; midas ) . \n however , it is possible to document the format of any hypothesis - driven or systematic experiment in xml , making it straightforward to use resource description framework ( rdf ) and web ontology language ( owl ) to share and analyze experimental designs , a critical step in making the results from complex experiments machine - interpretable in light of their purpose and context . \n although we demonstrate the application of sdcubes to microscopy data using imagerail , the sdcube format is in principle adaptable to any type of high - dimensional data , and we have created preliminary schemata for multi - color flow cytometry and multiplex or array - based biochemical assays ( see supplementary materials ) . \n matlab users will recognize that some sdcube functionality is already present in matlab , which makes extensive internal use of multi - dimensional data arrays ( indeed , matlab can read hdf5 files ) . \n however , matlab files can not duplicate key features of sdcubes : they can not be read incrementally , their data models can not be referenced to external ontologies or parsed using web - based tools , and matlab is not open - source an important consideration for a data standard . \n imagerail is designed to be interoperable with existing open - source image analysis software , including imagej , cellprofiler and ome interoperability is important to avoid duplication of effort but imagerail also needs to function as a stand - alone application ; hence the inclusion of common segmentation and visualization routines . \n the ability of sdcubes and imagerail to systematize data from complex dose - response experiments has made it possible to implement an efficient scheme for single - cell pharmacology . \n exposing tumor cells to growth factors and kinase inhibitors in combination reveals many examples of cell - to - cell variability ; some of these are likely to have non - genetic origins , by direct analogy to the variability observed in cellular responses to trail , t - cell receptor agonists and other ligands . \n variability is maximal at doses close to the ic50 of gefitinib or the ec50 of egf , precisely the doses likely to prevail in real patients . \n it therefore seems reasonable that application of single - cell pharmacology will help to uncover the basis of fractional killing by anti - cancer drugs and assist in dissecting the origins of intrinsic and acquired drug resistance . in many exploratory biological experiments , data collection and analysis are iterative processes undertaken by a limited number of people . in this environment , \n the high - integrity , multi - user , read - write operations enabled by conventional databases represent unnecessary overhead and sdcubes offer an effective alternative . \n however , as data become more mature or an experiment nears completion , it will often be advantageous to move key results to a relational database . \n one way to accomplish this is to create a specialized summary view of an sdcube and then import the summary data into a database . \n only data conforming to a pre - existing standard would be accessible in the database , but an sdcube containing all primary data could easily be called using a uniform resource identifier ( uri , akin to a web url ) . \n it is possible that new types of databases will be developed with science in mind ( e.g. , scidb ; http://www.scidb.org/ ) , but we predict that lightweight , adaptable , file - based data storage will always co - exist with server - based data management , and that sophisticated file formats such as sdcubes will provide a missing link between creative experimentation and machine - interpretable data . \n ", "role": "user" }, { "content": "whereas genomic data are universally machine - readable , data arising from imaging , multiplex biochemistry , flow cytometry and other cell- and tissue - based assays usually reside in loosely organized files of poorly documented provenance . \n this arises because the relational databases used in genomic research are difficult to adapt to rapidly evolving experimental designs , data formats and analytic algorithms . here \n we describe an adaptive approach to managing experimental data based on semantically - typed data hypercubes ( sdcubes ) that combine hierarchical data format 5 ( hdf5 ) and extensible markup language ( xml ) file types . \n we demonstrate the application of sdcube - based storage using imagerail , a software package for high - throughput microscopy . experimental design and its day - to - day evolution , not rigid standards , \n determine how imagerail data are organized in sdcubes . \n we apply imagerail to the collection and analysis of drug dose - response landscapes in human cell lines at the single - cell level .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: sperm from healthy fertile males , with a normal semen analysis , are normally prepared for imaging as follows . \n cells are isolated from the seminal plasma by swim up into supplemented earle 's balanced salt solution ( sebss ; mm : 1.8 cacl2.2h2o , 5.37 kcl , 0.81 mgso4.7h2o , 26.2 nahco3 , 1.0 nah2po4.2h2o , 116.4 nacl , 55.6 d - glucose , 2.73 na pyruvate , 41.8 na lactate ) supplemented with 0.3% charcoal de - lipidated / fatty acid free fraction v bsa ( quality of the bsa is crucial for successful capacitation of sperm ) \n . 1 ml of sebbs is pipetted into each of a series of 5 ml tubes and gently underlayered with 0.3 ml of semen . \n after incubation for 1 hour ( 37c ; 6% co2 ) the top 0.7 ml is gently removed from each tube and pooled . \n 10 l of the sperm suspension is diluted with 90 l of 1% ( v / v ) formalin to immobilize the cells , then sperm are counted in a neubauer chamber . \n cell density in the suspension is then adjusted ( with sebss ) to 6 million cells / ml . the sample is then divided into aliquots of 200 l in loosely - capped tubes and incubated ( 37c ; 6% co2 ) in for 5 - 6 h to allow capacitation . coverslips ( 22x50 mm ) have previously been treated with poly - d - lysine . \n 10 l of poly - d - lysine solution ( 10% w / v ) is applied as a number of small drops to the centre of the coverslip . \n a coverslip is attached with vacuum grease to an enclosed , purpose - built , perfusable , polycarbonate imaging chamber ( dimensions 35 mm x 20 mm x 5 mm ; capacity 180 l ) similar to the warner rc20 chamber .the poly - d - lysine - coated coverslip forms the base of the chamber when the cells are viewed on an inverted microscope and a 12 mm diameter circular coverslip forms the upper surface of the chamber , allowing transmission of light . \n oregon green bapta1-am ( ogb ) or calcium green 1-am are used for labeling cells . \n pluronic acid f127 ( a detergent ) is included in the dmso to prevent ' clumping ' of the dye . \n this can be prepared in the laboratory ( 100 mg pluronic in 0.5 ml dmso ) , immediately before use , or can be purchased pre - prepared . \n 20 l is added to a 50 g aliquot of ogb ( 2.5 mg / ml ) . \n after capacitation of the sperm ( 5 - 6 h in sebbs , 37c ; 6% co2 ) a tube is selected for imaging and 1.2 l of ogb solution is added , giving a final concentration of 10 m . \n the tube is then incubated for a further 40 min , after which the cell suspension is gently injected into the inflow port of the imaging chamber with a p1000 ( blue ) pipette tip . the chamber is placed in the incubator , poly - d - lysine - coated coverslip side down , for 20 min . \n cells tend to swim along the surfaces of the chamber and will adhere to the poly - d - lysine - coated area . \n the chamber is now mounted on the microscope , connected to the perfusion apparatus and perfused at approx 0.5 ml / min . \n a roller pump feeds saline into the chamber and overflow from the exit port is removed by a suction pump with trap . \n the preparation is left in the dark for at least 10 min whilst loose cells and extracellular dye are removed by perfusion of the chamber . \n temperature stability is crucially important because small fluctuations may not only affect cell ca homeostasis , but may also affect kd of the dye . \n experiments are normally performed at 25c , achieved by maintaining the temperature of the dark room at this level . \n we have found that maintaining room temperature at the required level provides greater temperature and focus stability than using a temperature controlled stage or a thermostatically controlled heater on the saline inflow . \n cells are viewed under phase contrast ( 40x or 60x oil - immersion ) objective and an area for imaging is selected . \n the portion of the poly - d - lysine coated area that is near the inlet port is preferred , where saline flow is laminar and consistent . \n it is also important to use an area where cell density is appropriate ( excessive density affects the quality and integrity of data through pickup of signal from adjacent cells ) and where cells are adequately attached but flagellar activity is discernible . \n the microscope is then switched to fluorescence mode ( excitation 480 nm ; emission 540 nm ) and exposure time is reduced to the minimum required to obtain a clear fluorescence image ( usually 50 - 200 ms ) . \n the experiment is started by activating the time - series image acquisition software ( iq ) . \n typically images are acquired at 0.1 hz and illumination is restricted to the periods of image acquisition only using a software controlled shutter . \n much greater image acquisition rates can be used but allowance must be made for problems of bleaching and generation of artifacts due to photo - damage to the cells ( see discussion ) . \n iq ( and most other acquisition software platforms ) will allow real - time graphing of fluorescence during the experiment . \n after a control period of 3 - 5 minutes duration manipulation of saline constituents ( such as [ ca]o ) and application of drugs is achieved by replacement of saline in the perfusion header . \n time of addition of each stimulus is noted so that time of arrival in the imaging chamber can be calculated , providing sufficient accuracy for assessment of the slow responses described here ( sampled at 0.1 hz ) . for more rapid responses greater accuracy can be achieved by adding stimuli directly to the saline flow through a second inflow port as provided in the warner rc20 chamber . \n regions of interest ( rois ) are drawn round each cell ( or part of cell ) and also a cell free area is selected ( for automatic background subtraction by the software . the image series is then checked to remove cells which died or underwent acrosome reaction ( which appears as a large and rapid increase in fluorescence followed by loss of cytoplasmic dye ) during the experiment and those that showed sufficient movement to cause artifacts when analyzed as a time series . a time - fluorescence intensity series \n initially fluorescence is normalized to the mean value obtained during the control period , using the equation r = [ ( f frest ) / frest ] x 100%,where r is % change in fluorescence compared to the control period , , f is fluorescence intensity at a time t and frest is the mean of at least 30 determinations of f obtained during the control period . \n figure 1 shows a series of images from an experiment in which the cells were stimulated with 3 m progesterone . \n the upper row and movie 1 show the fluorescence images in grey - scale and the same mages are shown below ( and in movie 2 ) in pseudocolor ( lookup table ' 16_colors ' in image j ) , where ' cool ' colors indicate low fluorescent intensity and ' warm ' colors indicate high fluorescence intensity . \n cells can be viewed in pseudocolor during the experiment , using lookup tables in iq , but using grey scale is generally more informative for assessing .whether the cells are well - labeled . \n the first two images were collected at 0 s and 100 s after commencing recording . \n fluorescence should be stable and tends to be strongest in the post acrosomal area and sperm neck . \n progesterone entered the imaging chamber at approximately 175 s and the 3 and 4 images ( 180 s and 220 s ) shows a rapid increase in [ ca ] ( fluorescence ) originating in posterior head and neck region of the cell . \n subsequent images are at 290 , 360 , 740 , 990 and 1440 s , showing the decay of the initial [ ca]i transient and development of a secondary sustained elevation . \n figure 2 shows a spreadsheet analysis , converting raw fluorescence values for each roi to normalized fluorescence ( % change in fluorescence compared to the control period ) figure 3 shows time - normalized fluorescence plots for 3 cells showing ' typical ' responses to 3 m progesterone . \n example data from a cell stimulated with progesterone . a series of fluorescence images in grey scale ( upper row ) and pseudocolor ( lower row ) are shown . \n time points are 0 , 180 , 220 , 290 , 360 and 990s . 3 m progesterone entered the imaging chamber at 175 s. rois are shown in the first panel . \n figures in red ( below ) are normalized data obtained using the equation given in the text . \n graph shows normalized fluorescence - time plot for cell 64 in this experiment which , upon stimulation , shows a transient rise in fluorescence followed by a slow rise and series of small oscillations . \n fluorescence - time traces for 3 individual cells , expressed as % change with respect to control value .. 3 m progesterone was added at the time marked by the arrow . \n figure 1 shows a series of images from an experiment in which the cells were stimulated with 3 m progesterone . \n the upper row and movie 1 show the fluorescence images in grey - scale and the same mages are shown below ( and in movie 2 ) in pseudocolor ( lookup table ' 16_colors ' in image j ) , where ' cool ' colors indicate low fluorescent intensity and ' warm ' colors indicate high fluorescence intensity . \n cells can be viewed in pseudocolor during the experiment , using lookup tables in iq , but using grey scale is generally more informative for assessing .whether the cells are well - labeled . \n the first two images were collected at 0 s and 100 s after commencing recording . \n fluorescence should be stable and tends to be strongest in the post acrosomal area and sperm neck . \n progesterone entered the imaging chamber at approximately 175 s and the 3 and 4 images ( 180 s and 220 s ) shows a rapid increase in [ ca ] ( fluorescence ) originating in posterior head and neck region of the cell . \n subsequent images are at 290 , 360 , 740 , 990 and 1440 s , showing the decay of the initial [ ca]i transient and development of a secondary sustained elevation . \n figure 2 shows a spreadsheet analysis , converting raw fluorescence values for each roi to normalized fluorescence ( % change in fluorescence compared to the control period ) figure 3 shows time - normalized fluorescence plots for 3 cells showing ' typical ' responses to 3 m progesterone . \n example data from a cell stimulated with progesterone . a series of fluorescence images in grey scale ( upper row ) and pseudocolor ( lower row ) are shown . \n time points are 0 , 180 , 220 , 290 , 360 and 990s . 3 m progesterone entered the imaging chamber at 175 s. rois are shown in the first panel . \n figures in red ( below ) are normalized data obtained using the equation given in the text . \n graph shows normalized fluorescence - time plot for cell 64 in this experiment which , upon stimulation , shows a transient rise in fluorescence followed by a slow rise and series of small oscillations . \n fluorescence - time traces for 3 individual cells , expressed as % change with respect to control value .. 3 m progesterone was added at the time marked by the arrow . \n when carried out successfully , this technique allows recording of the distribution and kinetics of spontaneous and induced ca signals in human sperm . \n responses can be obtained from a large number of cells ( up to 200 ) which is important since human sperm can show a lot of variation in their spontaneous and stimulated ca signals . \n successful labeling and survival of the cells during recording are highly dependent on sample quality . \n human sperm are very sensitive to photo - damage and we therefore use the minimal necessary illumination ( both intensity and exposure time ) in order to maximize cell survival and minimize artifacts due to cell death . a high - sensitivity camera ( permitting use of low - intensity illumination ) is a great benefit since the camera will pick up weak fluorescence . \n back - illuminated , em - ccd cameras are particularly well - suited , though very expensive . led illumination ( instead of using a xenon or mercury lamp with excitation filter \n we do not use fura-2 , despite the obvious advantages of ratio - metric imaging , because fura requires excitation with uv light and because it is necessary to take two images for each ratio . for data obtained with single wavelength , visible light dyes , \n normalization of the fluorescence intensity largely compensates for difference in dye loading between cells , but not for dye distribution within an individual cell , and this must be borne in mind . though single wavelength dyes can , in principle , be calibrated , the accuracy of the technique is poor and we do not attempt to do this . whereas the ratio data obtained with fura-2 ( or the emission ratio dye indo ) , even without calibration , give an acceptably faithful representation of relative changes in [ ca]i , the fluorescence intensity of the single wavelength dyes is far from linearly related to [ ca]i . over the most useful part of the saturation curve the relationship for single wavelength dyes usually approximates to logarithmic . \n we currently use oregon green bapta-1 ( figure 4 ) because it is sensitive to small changes in [ ca]i close to resting level s ( 50 - 100 nm ) . \n when [ ca]i rises above 1 m responses will be under - represented in terms of fluorescence change and the dye may saturate . an option for improvement of the technique without resorting to uv excitation is to double load cells with a dye such as fluo-3 and fura red . both can be excited at 488 nm but simultaneous their responses are very different . \n recording of emission at 540 and 650 nm provides a ratio which can provide a better method for accurate monitoring of [ ca]i ( haughland , 2002 ) and may be applicable to sperm ( nisigaki et al , 2006 ) . \n relationship between free [ ca ] ( nm ) and fluorescence emission at peak wavelength ( approx 525 nm ) for oregon green bapta-1 and oregon green bapta-2 . \n ogb1 gives a higher fluorescence at resting [ ca ] but saturates at lower levels and thus has a smaller useable range . \n data for these plots were obtained from the molecular probes handbook ( haughland , 2002 ) . \n ", "role": "user" }, { "content": "fluorescence microscopy of cells loaded with fluorescent , ca2 + -sensitive dyes is used for measurement of spatial and temporal aspects of ca2 + signaling in live cells . here \n we describe the method used in our laboratories for loading suspensions of human sperm with ca2 + -reporting dyes and measuring the fluorescence signal during physiological stimulation . \n motile cells are isolated by direct swim - up and incubated under capacitating conditions for 0 - 24 h , depending upon the experiment . \n the cell - permeant am ( acetoxy methyl ester ) ester form of the ca2 + -reporting dye is then added to a cell aliquot and a period of 1 h is allowed for loading of the dye into the cytoplasm . \n we use visible wavelength dyes to minimize photo - damage to the cells , but this means that ratiometric recording is not possible . advantages and disadvantages of this approach are discussed . during the loading period cells \n are introduced into an imaging chamber and allowed to adhere to a poly - d - lysine coated coverslip . at the end of the loading period excess dye and loose cells \n are removed by connection of the chamber to the perfusion apparatus . \n the chamber is perfused continuously , stimuli and modified salines are then added to the perfusion header . \n experiments are recorded by time - lapse acquisition of fluorescence images and analyzed in detail offline , by manually drawing regions of interest . \n data are normalized to pre - stimulus levels such that , for each cell ( or part of a cell ) , a graph showing the ca2 + response as % change in fluorescence is obtained .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: the national mesothelioma virtual bank ( nmvb ) was developed in 2006 to stimulate the good of mesothelioma patients , collaborative efforts are made to collect and distribute well - annotated high - quality mesothelioma specimens to facilitate the research utilizing these specimens and encouraging basic , translational , and developmental studies . \n the nmvb is funded by the center of disease control and prevention ( cdc ) in association with the national institute of occupational health and safety ( niosh ) [ 2 , 3 ] . \n there are four academic health centers which have new york university school of medicine ( nyu ) , university of pennsylvania ( u. penn ) , mount sinai school of medicine ( mssm ) , and university of pittsburgh medical center ( upmc ) [ 2 , 46 ] . with the collective efforts \n , nmvb is devoted to provide specimens from more than 1100 mesothelioma prospective and retrospective consented cases . \n nmvb provides fresh frozen , paraffin embedded blood products and three distinct tissue microarrays ( tma ) to facilitate the areas in mesothelioma research that includes biomarkers study , immunology , genetics , and therapeutics . the main objective of the nmvb is to provide a biorepository that can provide annotated specimens that are challenging to facilitate the initiation and performance of the research . \n the nmvb has addressed and overcome the challenges of most of the tissue banks are affected by providing sufficient number of mesothelioma cases , standardizing the data and specimen collection method , facilitating the sharing of information through nmvb database , and addressing the issues of constraint by confidentiality and de - identification . \n the collaborative efforts of four academic institutions provide a unique opportunity for sharing clinical , pathological , and follow - up data on mesothelioma patients , while sharing the logistics of informatics and collaborative research programs across the cancer research institutions . \n the nmvb resource provides a virtual repository of mesothelioma specimens located at the collaborative sites . \n each collaborative site keeps the autonomy of specimens , and information is shared through a well - standardized informatics platform , in order to make them available for mesothelioma research community . \n the nmvb resource is developed to provide the platform for sharing the well - annotated and highly characterized mesothelioma specimens for the mesothelioma research community for establishing collaborative research programs at the national level . \n we have envisioned that our experience in the development and deployment of tissue banking infrastructure will serve as a model for establishing tumor banks and collaborative research that will ultimately foster the translational research and provide highly characterized and well - annotated specimens to the research community . \n the nmvb resource was developed by the collaboration of the university of pittsburgh medical center , new york school of medicine , and the university of pennsylvania [ 2 , 4 , 5 ] . \n the resource has successfully served the mesothelioma research community and fulfilled the needs of researchers by providing hundreds of mesothelioma specimens . after successful completion of five years of funding , \n the resource was refunded in 2011 with the spirit of expanding the collaboration and serving the research community by providing mesothelioma specimens , in order to facilitate the basic and clinical science research that will ultimately provide the benefit to the patients . in the second phase of funding , \n , the resource gained access to mesothelioma cases and research facilities from four medical care settings that are performing a vital role in the research and management of mesothelioma patients . \n national mesothelioma virtual bank resource organization consists of the following three major elements ( figure 1 ) . \n the research evaluation panel ( rep ) is an independent group of experts that is created by the nmvb steering committee in consultation with the cdc program officer . \n the selection of rep members is based on their qualification , publications , and research experience in the mesothelioma research . \n the rep member could be a pathologist , biostatistician , physician , or an investigator that has a deep understanding of mesothelioma and has an up to date knowledge of recent advancement in the diagnosis and management of mesothelioma . \n the rep members work independently but collaboratively with the coordinating committee and without conflict of interests with the resource . \n they are responsible for reviewing requests from investigators for specimens and clinical data and evaluating the scientific merit of the request . \n the rep members then provide advice about the scientific quality and priority of the request to the resource nmvb steering committee . \n there are also nonvoting members who are members of nmvb steering committee who also provide their input on the specimen and data requests . \n rep members are selected for four years and the inclusion of new members / replacement is established with the consultation of the existing rep members , steering committee members , and cdc program officer . \n the rep chooses one of its members to be chairperson for a term of one to two years . \n the rep members will attend at least one steering committee meeting each year to help coordinate rep activities with those of the steering committee . \n the coordinating committee is comprised of the principal investigators from collaborative sites upmc , nyu , u. penn , and mssm and program managers from mesothelioma allied research foundation ( meso - foundation ) , cdc , and the national institute of occupational safety and health ( niosh ) [ 2 , 3 ] . \n the coordinating committee act as the governing body of the resource for developing operating policies that are implemented at each collaborative by their principle investigator . \n the committee reviews the operating procedures of the participating sites to insure that they are compatible with the overall goals and policies of the resource and comply with cdc and niosh defined specific quality control and tissue processing procedures [ 2 , 3 ] . \n the committee also overlooks the specimen requests that are approved by the rep and assure the fulfillment of requests as per resource protocols . \n the committee meets in person at least once a year with additional meetings as necessary . \n the meetings are aimed at coordinating the activities of the participating sites , establishing new policies and priorities , and reviewing progress . \n nmvb working group comprises of personnel from all collaborative sites that includes data managers , tissue bank technician , database administrator , cancer registrar , and research coordinator who handles day - to - day activities of the project . \n the working group meeting is conducted every month and project coordinator at the coordinator site reports , the progress to nmvb steering committee . \n the data managers are responsible for entering de - identified data of consented mesothelioma cases of their local site into the data entry interface of nmvb database . \n they are responsible for keeping and maintaining patient health information ( phi ) according to health insurance portability and accountability act ( hipaa ) and local institutional review board rules and regulations . \n the data manager of each collaborative site is the key personal that communicates regarding specimen collection and annotation with tissue bank technicians and cancer registry managers from their own institution . \n data managers will eventually be responsible for quality assurance standards within their center as they relate the data entered into the nmvb database . \n retrospective collection of nmvb arise clinically collected specimens ( fresh frozen and paraffin blocks ) containing specimens from surgical resection . \n pneumonectomy , pleural , and peritoneal resection , core needle biopsies , lymph nodes , and other biopsies or tissue specimens of metastatic mesothelioma sites are also collected . \n the local institutional review board ( irb ) waives the retrospective collection of specimen ; nmvb sites may bank existing specimens without patient consent . \n however , if a patient is alive and the patient needs to be contacted in order to obtain additional clinical information , each site will do so according to a written plan approved by their institutional review board . \n the honest broker searches mesothelioma cases in clinical information systems that are seen during the preceding year but are not consented due to various reasons . \n the patient denies consent for the study , either the consenting staff does not approach the patient or the collection site does not have research staff available at the time the patient visited for surgical or follow - up treatments . the honest broker compares the list of non - consented cases in nmvb honest broker log sheet to eliminate the possibility of prior enrollment into nmvb . \n the list of nonconsented patients is sent to nmvb principle investigator , clinical team ( surgeons , physicians , and nurses ) , and research nurse coordinator . \n alive and approaches their patients who were contacted via mailed letter in person or by phone to solicit their interest in the study . \n if the letter is sent , the honest broker obtains an electronic signature from each respective surgeon and sends a letter to the patient with study materials including either a response card to the study coordinator and/or phone number . the study coordinator and honest broker keep track of the patient consenting to nmvb with clinical team . \n the honest broker follows up with the clinical team periodically in the hope of improving the volume of participants . \n the selected cases are then sent to the tumor bank at each site so , the paraffin or fresh frozen samples can be collected from the clinical pathology department . \n the tissue bank makes a request to the pathology department to provide specimens for research purposes that are surplus to the clinical diagnostic use . upon the receipt of specimens , the honest broker enrolls the patient into nmvb database and collects data at the patient 's demographics , clinical pathology , and follow - up levels . \n the designated pathologist reviews the section slides of the case and completes the specimen and block level information in nmvb database . \n the participants are approached on their clinical visit at each collaborative site for the purpose to enroll in nmvb study by the research nurse coordinators or physicians . \n the clinical research nurse coordinator asks the participants to review a copy of the informed consent form ( national mesothelioma virtual registry and tissue bank ( nmvrtb ) consent form ) prior to seeing their physicians . \n the clinical research nurse coordinators or physicians review the informed consent form with participants and address any questions or concerns prior to obtaining written informed consent for their biospecimens contribution to the nmvb study . \n they also address any future questions or concerns of nmvb participants and provide the patient with a nmvb health assessment questionnaire that can be completed later at their convenience . \n the participants are also informed that the research studies in which their donated specimens will be used will be directed at mesothelioma research . \n however , it is unlikely that their donated specimens are used in research studies directed at other diseases or conditions . \n the specimens from consented patients are stored at the tumor banks of each participating institute and de - identified information is shared through a web - based interface of nmvb database . after the participants undergo surgical treatment , tumor banks at each site collect the specimen and store them in the bank . \n the data manager enrolls the participant in the nmvb database and completes the patients de - identified demographic , epidemiology , pathology , and follow - up information . to collect standardized data that can be uniform , consistent , understandable , and shareable , the common data elements ( cde ) \n were developed to allow annotation of cases and to accomplish characterization of biospecimens collected from different collaborating sites . \n the development of cdes for the resource has been described in detail in a related publication from our group . in summary , \n the cde development was by joint consensus of participants under the leadership supervision of the nmvb coordinating committee . \n the cdes include cancer registry data ( demographic , epidemiology , and follow - up ) at the patient level , pathology data at the specimen level including data elements to elaborate tnm staging and tumor grading , along with block level annotation and genotype data . \n the cde subcommittee used the experiences gained from previous projects and major standards used to develop the cdes include the naaccr data standards for cancer registries , cap cancer protocol and checklist , the association of directors of anatomic and surgical pathology ( adasp ) , and the american joint committee on cancer ( ajcc ) cancer staging manual [ 4 , 710 ] . \n the collected data from collaborative sites is reviewed at the nmvb coordinating ( database ) site , which processes the data according to quality assurance ( qa ) and quality check ( qc ) protocols quarterly that have been established by the resource . \n the process of qa / qc is performed to locate any missing datasets and errors performed during data recording . \n the value of each data set is matched with the cde dictionary to make certain that the standards are being followed during data recording . \n only the standardized data is uploaded into the database at regular basis , and data with errors is sent back to the corresponding sites along with explanations of rejection . \n the resource selects 5% of the newly entered cases to be reevaluated by honest brokers , cancer registrars , and data managers . \n after completion of their review , the audit reviewers submit a report of their findings and recommendations to the resource . \n the resource members discuss their findings in the subsequent general meeting of the nmvb coordinating committee and make additional plans to implement the proposed recommendations . \n the nmvb resource has periodic quality assurance and quality control of pathology data by assessing interobserver concordance for the resource pathologists . \n these consist of two methods which include ( 1 ) a joint review of cases at meetings and ( 2 ) an independent review of cases circulated amongst the participating sites . for joint qa review during meetings , \n resource pathologists review up to 5 cases from each site , with an emphasis on the 5 matrix slides selected by each pathologist at each site to include areas of difficulty or likely diagnostic differences . \n joint review of cases is performed on a multiheaded microscope that permits pathologists to discuss diagnostic differences and set thresholds . \n independent review of cases is performed by individual pathologist at each site on cases sent from the other collaborative sites at regular intervals . \n the data managers at each site will randomly select the cases for qa review from those added to the resource within certain cut - off dates . \n the review will be documented by completing the matrix fields and select , histology \n any areas that show a high level of discrepancy will be determined by data managers and communicated to resource pathologists . \n the pathology subcommittee will then discuss their findings in the subsequent general meeting of the coordinating committee and provide a report with recommendations as indicated by their findings . \n the nmvb has designed its procedures to protect the confidentiality and privacy of human subjects and irb approval has been obtained for all activities . nmvb uses a decentralized system for specimen and data collection and storage . each case \n the only link to patient identity is held in reserve locally within the institution and there are no links directly connecting specimens or data to patients . \n the nmvb database is available to the research community on a public website but it is designed to produce only de - identified datasets upon query . \n this is possible because only de - identified data sets exist which are compliant with the safe harbor approach to hipaa ( health insurance portability and accountability act ) . \n safe - harbor approach entails the removal of all 18 identifiers enumerated at section 164.514(b ) of the regulations . \n the honest broker acts as a barrier between fully identified confidential clinical patient information and the completely de - identified data made available to the research community . \n an honest broker is an individual , organization , or system acting for or on behalf of the covered entity to collect and provide health information to the investigators in such a manner whereby it would not be reasonably possible for the investigators or others to identify the corresponding patients - subjects directly or indirectly . \n a researcher may use the services of an honest broker service to obtain the protected health information in a de - identified manner . \n de - identification means that researchers or others can not identify the patients - subjects directly or indirectly through identifiers link to the patient - subject . \n this honest broker service will de - identify medical records information by automated or manual methods . \n all honest broker services are approved in advance by both the irb of record and collaborative sites of nmvb . \n the honest brokers are individuals who have clinical responsibilities as tissue bankers , data managers to manage the pathology data , or as cancer registry specialists in cancer registry . based on their clinical job duties , \n the nmvb database is developed by utilizing a uml ( spell it out ) class diagram . \n unified modeling language ( uml ) is a nonproprietary language for constructing , visualizing , and documenting the artifacts of software engineering . the information model for cdes is developed to establish a structurally aligned generalized relationship . \n the informatics model of database facilitates is achieving semantic and syntactic interoperability by describing the common data elements in the form of metadata or data descriptors and by using a controlled vocabulary in order to make the data understandable and sharable for end - users . \n the system architecture is designed to provide query speed and high security as well as expansion capabilities for incorporating new data elements or integrating existing systems at participating institutions . \n the nmvb web - based query tool is based on the catissue clinical annotation engine ( cae ) version 3.0 application . \n the database provides three levels of access to end users , first , nmvb statistical data for public view , second , approved investigator database query that allows seeing individual patient de - identified clinical data , and third , data manager access to query and edit the stored data . \n the nmvb database allows researchers to search clinically annotated mesothelioma biospecimens via a web interface . \n the database facilitates standardized clinical annotation structure and incorporates a variety of data sets from different data sources . \n two methods of annotation have been adopted manually using web - based manual data entry tool and data imported electronically through excel files . \n the resource also provides more than 1300 biospecimens including over a thousand tumor blocks that are accrued from surgical resections and biopsies and also includes blood products as well ( plasma , serum , whole blood , red blood cell , pmbc and buffy coat ) . \n this collection is made possible by the joint effort of all the collaborative sites . at the end of 2011 \n we are hoping to have over 1100 annotated cases of pleural , peritoneal , and pericardial mesothelioma specimens including fresh frozen , paraffin embedded blood products available to the mesothelioma research community ( figure 2 ) . in addition , the resource provides three distinct tissue microarrays ( tmas ) that have been made available to investigators along with de - identified clinicopathology and follow - up data in excel and xml format [ 1 , 17 ] . \n this interface allows data managers at each of the collaborative sites to enroll mesothelioma cases and enter de - identified information at patient 's demographic epidemiology , pathology , and follow - up data sets in control access environment . \n this prohibits data managers of one site to enter and edit the case information of other collection sites . \n the data managers can create their own case list as per their account assignment and export results as per selected data elements . \n the nmvb database also provides access to the query tool that is secured and password protected and only investigators approved by irb and scientific review committee are capable to access the database . \n it permits end - users to develop their own case lists for their applications and query the data related to the specimen cases they have received from the resource for their approved studies . \n the query results show only de - identified datasets associated with each approved case through disease and specimen pre - defined views of the data . \n the nmvb statistical database / public view interface is available to the research community ( figure 4 ) ( be consistent with your style ) . \n the statistical database for public query provides summary statistics on all the mesothelioma cases and their associated biospecimens stored into nmvb resource . \n the result page shows the number of cases , specimens , and blocks in the database that match with query criteria of the investigator and general statistics on a limited number of data elements . by utilizing this public view database , \n the investigator could be able to gain enough information to decide if the resource has sufficient biospecimens to fulfill his or her research needs . \n in the era of genomics and proteomics , nmvb has realized the distinct utility and growing interest of mesothelioma research community and developed three distinct tissue microarrays . \n each of the collaborating site constructed tma from the cases that are collected and stored at their sites . \n tma is a type of tissue assay that permits the investigator to visualize and study tissues from hundreds of patients . \n the detailed information is available via nmvb website and investigator can obtain data associated with each tma in excel and xml format . \n in addition , we have provided whole slide image of each tma slide so investigator can visualize each core at 20x to 40x magnifications . \n a brief description on each tissue microarray is as shown in ( table 1 ) . \n the main objective of the nmvb resource is to provide high quality and well - annotated mesothelioma specimens to the research community . in the last seven years \n , nmvb has provided hundreds of mesothelioma specimens ( tissue and blood ) and dozens of tissue microarray slides . \n the investigator can obtain the specimen and data by submitting a letter of intent ( loi ) electronically via nmvb website or send the loi via e - mail to the project coordinator . \n the detailed information about the availability of specimen and obtaining the specimen from resource is available on the nmvb website ( http://www.mesotissue.org/ ) . \n all submitted lois are initially evaluated at the coordinating site that includes the authentication of investigator by verifying investigator 's credentials and irb approval of the study from the applicant 's institution . \n after the initial review , loi is forwarded to rep which determines the validity and justification of the use of specimens from the resource . \n the rep provides its decision and the applicant is notified about the decision on the loi . \n if rep approves the request , loi is processed further and material transfer agreement is also processed prior to shipping the requested specimen . if the request is denied , a formal letter with feedback from rep is sent to the applicant and a provision is granted to the applicant to resubmit the loi after addressing the concerns that are pointed out by the rep . \n the resource has adopted various types of media resources to advertise the nmvb biospecimens and services to the research community . \n the nmvb website provides general information about the resource and different types of specimens available to the research community . \n we circulate a quarterly announcement letter via mass marketing e - mailing to investigators that invites them to utilize the resource . \n advertisement is made through specialty scientific journals , research society newsletters , fliers at research meetings , posters and podium presentations , marketing booths at scientific research meetings , and free listings in journals and websites . \n all collaborative sites of nmvb resource collect and harbor specimens locally within their own tissue banks , while the data and information related to these specimens maintain a centrally located bioinformatics and data management system that is accessible to the members of the network and research community . \n the resource has established and implemented the decentralized collection and storage with a centralized data management model successfully . during the last six years \n , the resource has faced many challenges and barriers and yet has overcome them with collaborative efforts and experiences from the previous tissue banking infrastructure development and implementations . \n one of the key issues that arose after the initial development of the nmvb resource was to consent mesothelioma patients prospectively . to consent patients prospectively \n , there was a need of creating a clinical research team that has the ability to approach the patients preoperatively and postoperatively to consent and enroll them in the nmvb study . \n the clinical research team consists of a research nurse coordinator , thoracic or gastroenterology oncology surgeons , and physicians . a well - defined and highly effective workflow ( described above ) for prospective enrollment and specimen collection has been established and implemented for all of the nmvb collaborative sites . \n each site has developed its own consent form to consent and enroll mesothelioma patients for nmvb prospectively and obtained approval from their local irb . \n efforts have been successful in the placement of a health assessment questionnaire to obtain patient 's demographic , previous medical conditions , occupation , exposure to harmful substances including asbestoses , and pertinent family history . \n this questionnaire is handed over to the patients at the time of consent and requests from the patient to complete it at their convenience . \n the research nurse coordinator is responsible for the collection of questionnaire and sending it to data management team so they can store the patient 's questionnaire information in the nmvb database . during the process of prospective enrollment \n , we have realized that even with enormous team efforts and a well - organized workflow of prospective collection , we have not been able to successfully consent a considerable fraction of the mesothelioma patients . \n there are several reasons to explain the less than optimal completion of the consent process such as the shortage of trained research staff at the consenting sites , patient refusal for consent , and a lack of follow - up to consent . to address these issues and improve the enrollment , \n nmvb principle investigators and working group members have now established a workflow to identify missing mesothelioma cases at each site and enroll them into nmvb resource . \n the data manager at each collaborative site searches for mesothelioma cases which are seen at their corresponding sites in the previous years . \n the data managers cross check these cases with their prior mesothelioma enrollment in nmvb database . \n the data managers then prepare a list of nonconsented cases at their site and identify the vital status on them . \n the patients with vital status alive are contacted by their treating physician and surgeons to consent for the nmvb study . \n the deceased patients are also enrolled in nmvb study as per irb exempt approval . \n data managers at each collaborative site carry out the clinical annotation process and data extraction process . \n these processes are performed manually from data sources that include medical record systems , pathology reports , cancer registry , and laboratory information systems . \n the collected data is then standardized , de - identified , and stored in the database as per the approved study protocols . \n there are many challenges in data collection , processing , and storage that we have faced and resolved in the last six years . in data collection process , \n the most common issue we dealt with was to identify the same patient in different hospital data sources . \n this issue is resolved by developing a patient tracking system that links patient 's common identifiers with study identification number through keeping honest broker log sheet . by employing this solution , we are able to identify the same patient across various hospital sources , collecting the accurate data in precise context and reducing the chances of errors in data recording significantly . \n this solution addresses the challenges in manual data collection and entry into database by the data managers . to protect patient health information , \n a de - identification process is adopted which includes removing patient 's clinical identified data sets from the medical records and separating these from the research de - identified data sets . \n this process is done by honest brokers who act as the information barriers between clinically identified data sets and the de - identified research data sets . \n the honest broker collects clinical data , identifies the patient identifiers , separates them by assigning the research de - identified numbers , and finally making the de - identified data set available to the community . \n nmvb has adopted a very comprehensive and robust specimen processing and storing protocol and has enforced it at all collaborative sites . \n they are responsible for responding to pages from the operation room and doctor 's office . \n the technician takes the tissue into the frozen section room or the pathology gross dissection room and records warm ischemic time , weigh the tissue , and properly record it on the specimen sheet . \n the technician notifies the pathologist on call that tissue is available for banking and ready for gross evaluation . \n the technician assigns the nvmb study number to the case and records subjects name and nmvb number in the nmvb study log . \n the samples are divided into three pieces and processed . the first piece of tissue sample is placed in a bitran bag and freezed in isopentane ( bulk frozen ) . \n the second one is placed in formalin to be processed to freshed frozen paraffin embeded ( ffpe ) . \n this process is repeated for each tissue sample and label the sample a1 , a2 , and a3 , respectfully , for as many pieces that you receive . \n the second sample on the same subject would read b1 , b2 , b3 , and so on . \n the bulk frozen and the oct tissue samples are placed in a labeled plastic bag in the 80c freezer in the freezer repository . \n nmvb is a robust informatics supported mesothelioma biorepository that not only provides annotated biospecimen to the research community but also provides a unique platform for enabling collaborative research . to accomplish this goal , \n nmvb will also participate as a pathology informatics core in a recently submitted specialized program of research excellence ( spore ) mesothelioma grant supported by national cancer institute ( nci ) . \n nmvb will also assist in establishing a standardized tumor bank infrastructure and regulatory compliance frameworks for collaborating institutions that will participate in spore mesothelioma project as a specimen and data sites . \n these new collection sites will collect annoated mesothelioma biospecimen for the spore mesothelioma project and link them to the established nmvb collection sites ( as described above in this paper ) . \n this partnership will enable mesothelioma research community to have access to a larger resource of well - annotated mesothelioma specimens through the infrastructure of the nmvb distribution network . \n this expansion will allow for a large and diverse set of patient specimens to be shared for translational and applied research for the mesothelioma community . \n the nmvb acts as a central resource for mesothelioma annotated biospecimens for investigators using experimental methods in translational , histopathology , validation , and outcomes measures at national and international levels . \n this nmvb resource has been developed on a robust and efficient informatics infrastructure that facilitates a well - crafted workflow management , a standardized collection processes and a subsequent detailed clinical and pathological annotation of diverse cases across multiple collaborative sites . \n this resource provides a standard manual of operations and procedures , a histopathology guide , and a database with common data elements for characterization of mesothelioma biospecimens , multimodal datasets , and a quality assurance and control process that is intimately integrated within this process . \n the nmvb web - based query tool allows researchers to search clinically annotated biospecimens efficiently that are pertinent to their research areas . \n the web - based query tool ensures the patient 's health information protection by disclosing only de - identified data with institutional review board ( irb ) and scientific review committee approved standards and protocols . \n in addition , nmvb website provides an online process of requesting access to using mesothelioma biospecimen , a statistical query tool for the public view and access to approved investigator query tool to potential investigators . \n the biospecimens disbursement and database access to patient de - identified clinical data is granted after research evaluation panel ( rep ) approval . \n in fact nmvb provides a foundation for the development and implementation of an integrated tissue banking program and facilitates other tissue banking efforts through the members of the collaborative resource and their associated publications .", "role": "user" }, { "content": "the national mesothelioma virtual bank ( nmvb ) , developed six years ago , gathers clinically annotated human mesothelioma specimens for basic and clinical science research . during this period , \n this resource has greatly increased its collection of specimens by expanding the number of contributing academic health centers including new york university , university of pennsylvania , university of pittsburgh medical center , and mount sinai school of medicine . \n marketing efforts at both national and international annual conferences increase awareness and availability of the mesothelioma specimens at no cost to approved investigators , who query the web - based nmvb database for cumulative and appropriate patient clinicopathological information on the specimens . \n the data disclosure and specimen distribution protocols are tightly regulated to maintain compliance with participating institutions ' irb and regulatory committee reviews . \n the nmvb currently has over 1120 annotated cases available for researchers , including paraffin embedded tissues , fresh frozen tissue , tissue microarrays ( tma ) , blood samples , and genomic dna . \n in addition , the resource offers expertise and assistance for collaborative research . \n furthermore , in the last six years , the resource has provided hundreds of specimens to the research community . the investigators can request specimens and/or data by submitting a letter of intent ( loi ) that is evaluated by nmvb research evaluation panel ( rep ) .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: low back pain , which causes severe morbidity in society , is one of the primary reasons for contacting a doctor . in industrialized societies , \n 80% of individuals experience an attack of low back pain at least once in their lifetime [ 35 ] . \n while most of these attacks get better with moderate rest , medical treatment , and exercise , 10% become chronic . \n low back pain which becomes chronic is an important health problem that creates a heavy economic burden , as it causes workforce loss along with high treatment expenses . \n even though there are several areas in the lumbar region which might cause pain , one of the most common causes of pain is a herniated intervertebral disc that compresses nerve roots and causes the pain . even though the actual reason is not known , it is believed that mechanical and inflammatory mechanisms play a role in the situation . \n mixter and barr described the relationship between disc herniation and sciatica clearly in their article published in 1934 . \n successful results recorded in conventional discectomy applied through the open surgery method also confirmed this relationship . unfortunately , along with its success , several complications have been reported for the open surgery method [ 1216 ] . \n complications include recurrent herniation , failed back surgery syndrome that results in epidural fibrosis , general problems such as prolonged hospital stay , complications related to general anesthesia , and infections . in 1987 , williams reported in his study publishing microdiscectomy series that clinically successful results are independent of the disc material removed . \n carragee et al stated that the success ratio in small , unfragmented contained disc herniations with open surgery is lower when compared to large , fragmented uncontained disc herniations . \n successful results were observed to be independent of the amount of removed disc material , which directed researchers to minimally invasive methods such as percutaneous disc decompression . \n percutaneous disc decompression methods rely on the principle that small amounts removed from the disc will result in disproportionately significant relief in the intradiscal pressure . therefore , pressure on the nerve will be removed and radicular leg pain will be eliminated . \n percutaneous disc decompression methods , such as chemonucleolysis , manual disc decompression , automatic disc decompression and laser discectomy , have aroused interest for the last 40 years and have seriously evolved . \n implementation of these methods was limited since some of them are cumbersome , expensive , and require full equipment , along with having inconsistent results and various complications [ 2123 ] . \n percutaneous nucleoplasty ( pn ) is a method in which disc decompression is provided through controlled evaporation of nucleus pulposus using radiofrequency energy . \n it is supposed that the mechanism of clinical efficacy of the pn procedure is that pn alters the expression of inflammatory cytokines such as il-3 , which may be related to the mechanisms of pain relief and repair response within the disc . \n the most important advantage of this method is its ease , short application period , relatively lower cost , and safety . \n although pn is commonly applied , few studies have demonstrated the long - term efficiency of this method . \n the purpose of this prospective study with 2-year follow - up was to prove the hypothesis that pn is effective in relieving pain in patients with chronic radicular pain . \n there are a few studies with a follow - up period of more than 1 year in the english literature . \n upon obtaining institutional review board approval , the study was conducted with outpatients in the pain center of the university hospital between june 2005 and december 2008 . after all patients were informed orally and in writing on the pn application and the study , their written consent for accepting the application and participating in the study was obtained . \n the study design was prospective , non - controlled and non - randomized , with a 2-year follow - up period . \n patients inclusion and exclusion criteria were determined mainly according to the instructions by sharps and isaac . \n the following were used as the patients inclusion criteria : 1 ) age younger than 60 years , accepting pn practice and study participation ; 2 ) had lumbar disc hernia with mostly single - side leg pain ; 3 ) not responding to non - invasive conservative treatment methods such as medical treatment , rest , physical therapy applied at least for 6 weeks within the last 6 months ; 4 ) preserved disc height of more than 70% ; and 5 ) having single - level herniation smaller than 6 mm , and smaller than one - third of the sagittal radius of the spinal canal in mr imaging ( mri ) taken within the last 6 months . \n the following were the exclusion criteria : 1 ) patients not giving consent to take part in the study and the intervention ; 2 ) having back pain more than leg pain ; 3 ) having previous open surgery or percutaneous intervention on pn planned level ; 4 ) having more than 1 herniation with different levels ; 5 ) having uncontained extruded or sequestrated herniations larger than 6 mm in mri ; 6 ) having tumor , spondylolisthesis and spinal instability ; and 7 ) presence of general contraindications preventing invasive process application , such as bleeding diathesis , known allergy history for materials used , psychological disorder , or systemic infection or local infection in the intervention area . \n after single - dose 1 gr cefazolin sodium was given intravenously as prophylactic , patients were laid on the fluoroscopy table in the prone position under standard monitorization . after placing a pillow under the stomach in order to straighten lumbar lordosis , \n the intervention area was cleaned with iodine antiseptic solution and draped in accordance with sterility rules . \n the target point was reached by putting the c - arm in the oblique position . \n after vertebral end - plates were drawn in 1 line , the target disc was penetrated with a 17 g 6-inch crawford type introducer needle ( arthrocare , sunnyvale , ca , usa ) . through anterior - posterior and lateral imaging , \n the needle tip was kept at the junction of the annulus fibrosus and nucleus pulposus . \n then , the perc - dle spinewand ( arthrocare , sunnyvale , ca , usa ) was placed into the introducer needle , and advanced until the inner surface of the annulus was on the opposite side . \n the process was completed by creating a total of 6 channels at the 12 , 2 , 4 , 6 , 8 , and 10 oclock positions through ablation - coagulation in the nucleus with circular movements . \n patients were sent to the recovery room after the operation , where they would stay for 4 hours . \n patients who were evaluated only in terms of early complications at this stage were then discharged with recommendations . in the postoperative period \n the patients were permitted to walk , sit and stand without restriction , and to return to light to moderate work 3 or 4 days later . \n they were told that they could also start gentle stretching exercises at home 2 weeks later . \n patients were asked questions by an independent doctor , who did not take part in the study , about their pain , physical functional status and patient satisfaction in the preoperative period and postoperatively at 1 , 6 , 12 and 24 months . \n while pain was evaluated through vas ( visual analog scale , with 0 being no pain and 10 being the most severe pain ) , physical condition was evaluated in accordance with the oswestry disability index ( odi ) . \n patent satisfaction was graded as the following : 1 not satisfied 2 average , 3 good , and 4 excellent . \n furthermore , information on age , sex , herniation level and side , and duration of pain were collected for analysis . \n a positive post - therapeutic outcome for the patient was defined as a reduction in the pre - operative vas and odi scores of at least 30% . \n all data were analyzed using the statistical package spss version 15.0 for windows and medcalc version 10.3.0.0 for windows . \n repeated measurements anova parametric test for repeated measurements was used to evaluate the improvements in vas and odi scores both before and after the procedure . when the repeated measurements anova test showed a statistical difference , we used a paired samples t - test with bonferonni s correction to perform pairwise comparisons . \n we used the independent t - test to study the effects of sex and side of body treated on the outcomes , and used the correlation and regression analysis to analyze correlation between changes in vas scores and duration of pain and between changes in vas scores and age . \n upon obtaining institutional review board approval , the study was conducted with outpatients in the pain center of the university hospital between june 2005 and december 2008 . after all patients were informed orally and in writing on the pn application and the study , their written consent for accepting the application and participating in the study was obtained . \n the study design was prospective , non - controlled and non - randomized , with a 2-year follow - up period . \n patients inclusion and exclusion criteria were determined mainly according to the instructions by sharps and isaac . \n the following were used as the patients inclusion criteria : 1 ) age younger than 60 years , accepting pn practice and study participation ; 2 ) had lumbar disc hernia with mostly single - side leg pain ; 3 ) not responding to non - invasive conservative treatment methods such as medical treatment , rest , physical therapy applied at least for 6 weeks within the last 6 months ; 4 ) preserved disc height of more than 70% ; and 5 ) having single - level herniation smaller than 6 mm , and smaller than one - third of the sagittal radius of the spinal canal in mr imaging ( mri ) taken within the last 6 months . \n the following were the exclusion criteria : 1 ) patients not giving consent to take part in the study and the intervention ; 2 ) having back pain more than leg pain ; 3 ) having previous open surgery or percutaneous intervention on pn planned level ; 4 ) having more than 1 herniation with different levels ; 5 ) having uncontained extruded or sequestrated herniations larger than 6 mm in mri ; 6 ) having tumor , spondylolisthesis and spinal instability ; and 7 ) presence of general contraindications preventing invasive process application , such as bleeding diathesis , known allergy history for materials used , psychological disorder , or systemic infection or local infection in the intervention area . \n after single - dose 1 gr cefazolin sodium was given intravenously as prophylactic , patients were laid on the fluoroscopy table in the prone position under standard monitorization . after placing a pillow under the stomach in order to straighten lumbar lordosis , \n the intervention area was cleaned with iodine antiseptic solution and draped in accordance with sterility rules . \n the target point was reached by putting the c - arm in the oblique position . \n after vertebral end - plates were drawn in 1 line , the target disc was penetrated with a 17 g 6-inch crawford type introducer needle ( arthrocare , sunnyvale , ca , usa ) . through anterior - posterior and lateral imaging , \n the needle tip was kept at the junction of the annulus fibrosus and nucleus pulposus . \n then , the perc - dle spinewand ( arthrocare , sunnyvale , ca , usa ) was placed into the introducer needle , and advanced until the inner surface of the annulus was on the opposite side . the process was completed by creating a total of 6 channels at the 12 , 2 , 4 , 6 , 8 , and 10 oclock positions through ablation - coagulation in the nucleus with circular movements . \n patients were sent to the recovery room after the operation , where they would stay for 4 hours . \n patients who were evaluated only in terms of early complications at this stage were then discharged with recommendations . in the postoperative period \n the patients were permitted to walk , sit and stand without restriction , and to return to light to moderate work 3 or 4 days later . \n they were told that they could also start gentle stretching exercises at home 2 weeks later . \n patients were asked questions by an independent doctor , who did not take part in the study , about their pain , physical functional status and patient satisfaction in the preoperative period and postoperatively at 1 , 6 , 12 and 24 months . \n while pain was evaluated through vas ( visual analog scale , with 0 being no pain and 10 being the most severe pain ) , physical condition was evaluated in accordance with the oswestry disability index ( odi ) . \n patent satisfaction was graded as the following : 1 not satisfied 2 average , 3 good , and 4 excellent . \n furthermore , information on age , sex , herniation level and side , and duration of pain were collected for analysis . \n a positive post - therapeutic outcome for the patient was defined as a reduction in the pre - operative vas and odi scores of at least 30% . \n all data were analyzed using the statistical package spss version 15.0 for windows and medcalc version 10.3.0.0 for windows . repeated measurements anova parametric test for repeated measurements \n was used to evaluate the improvements in vas and odi scores both before and after the procedure . when the repeated measurements anova test showed a statistical difference , we used a paired samples t - test with bonferonni s correction to perform pairwise comparisons . \n we used the independent t - test to study the effects of sex and side of body treated on the outcomes , and used the correlation and regression analysis to analyze correlation between changes in vas scores and duration of pain and between changes in vas scores and age . \n two of these patients did not benefit from nucleoplasty despite technically successful procedures , and 1 of these patients was taken into open microdiscectomy after follow - up on the 6th month . \n the other patient was taken into the same operation after follow - up on the 12 month . \n four out of 56 patients were lost from the study during the follow - up period . \n one of these patients was lost at the 6 month after pn , 1 after the 12 month , and another 2 were lost to follow - up after the 24 month . \n the average age was 4010.7 years ( range 1859 ) , and 30 patients ( 53.6% ) were female . in all patients , \n the average pain period was 14.68.5 months ( range 636 ) , and decompression was mostly applied at the l4l5 level ( 58.9% ) . \n the mean vas score of the patients before the operation was 8.71.1 , and decreased to 3.51.7 at 1 month ( p<0.001 ) . \n vas scores at 6 , 12 and 24 months were 4.71.9 ( p<0.001 ) , 4.61.7 ( p<0.001 ) , and 3.41.9 ( p<0.001 ) , respectively ( figure 1 and table 2 ) . at 24 months \n we calculated the percentage of improvement in vas from baseline to 2 years as 60.9% . \n factors such as age ( p=0.501 ) , sex ( p=0.526 ) , and side ( p=0.839 ) did not have significant effect on vas at 24 months , but a negative correlation was observed with the duration of pain ( correlation coefficient r=0.4741 , p=0.0005 ) . \n furthermore , we found a positive correlation among patients in the decreases in vas and odi scores in the 24 month compared to the baseline period ( correlation coefficient r=0.9088 , p<0.0001 ) . \n the average initial score was 76.110.2 , and it was determined to be 34.114.8 at the first control after the procedure ( p<0.001 ) . \n average odi scores were 40.815.2 ( p<0.001 ) , 41.413.5 ( p<0.001 ) , and 33.914.9 ( p<0.001 ) at 6 , 12 , and 24 months , respectively ( figure 1 and table 2 ) . \n the percentages of patients reporting greater than 30% improvement in odi scores were 82.1% at 24 months ( figure 2 ) . \n we calculated the percentage of improvement for odi from baseline to 2 years as 55.4% . when the follow - up at 24 months was taken as a reference , 48 out of 56 patients ( 85.7% ) had improvement in their physical function when compared to the baseline value . when patient satisfaction levels were examined in accordance with the 4-point patient satisfaction scale , the percent of those stating \n good and excellent was 66% ( 23 persons ) at the last follow - up . \n no early or late complications such as discitis , nerve damage , or bleeding caused by pn applications were observed in the patients . \n two of these patients did not benefit from nucleoplasty despite technically successful procedures , and 1 of these patients was taken into open microdiscectomy after follow - up on the 6th month . \n the other patient was taken into the same operation after follow - up on the 12 month . \n four out of 56 patients were lost from the study during the follow - up period . \n one of these patients was lost at the 6 month after pn , 1 after the 12 month , and another 2 were lost to follow - up after the 24 month . \n the average age was 4010.7 years ( range 1859 ) , and 30 patients ( 53.6% ) were female . in all patients , \n the average pain period was 14.68.5 months ( range 636 ) , and decompression was mostly applied at the l4l5 level ( 58.9% ) . \n the mean vas score of the patients before the operation was 8.71.1 , and decreased to 3.51.7 at 1 month ( p<0.001 ) . \n vas scores at 6 , 12 and 24 months were 4.71.9 ( p<0.001 ) , 4.61.7 ( p<0.001 ) , and 3.41.9 ( p<0.001 ) , respectively ( figure 1 and table 2 ) . at 24 months \n we calculated the percentage of improvement in vas from baseline to 2 years as 60.9% . \n factors such as age ( p=0.501 ) , sex ( p=0.526 ) , and side ( p=0.839 ) did not have significant effect on vas at 24 months , but a negative correlation was observed with the duration of pain ( correlation coefficient r=0.4741 , p=0.0005 ) . \n furthermore , we found a positive correlation among patients in the decreases in vas and odi scores in the 24 month compared to the baseline period ( correlation coefficient r=0.9088 , p<0.0001 ) . \n the average initial score was 76.110.2 , and it was determined to be 34.114.8 at the first control after the procedure ( p<0.001 ) . \n average odi scores were 40.815.2 ( p<0.001 ) , 41.413.5 ( p<0.001 ) , and 33.914.9 ( p<0.001 ) at 6 , 12 , and 24 months , respectively ( figure 1 and table 2 ) . the percentages of patients reporting greater than 30% improvement in odi scores were 82.1% at 24 months ( figure 2 ) . \n we calculated the percentage of improvement for odi from baseline to 2 years as 55.4% . \n when the follow - up at 24 months was taken as a reference , 48 out of 56 patients ( 85.7% ) had improvement in their physical function when compared to the baseline value . \n when patient satisfaction levels were examined in accordance with the 4-point patient satisfaction scale , the percent of those stating \n good and excellent was 66% ( 23 persons ) at the last follow - up . \n no early or late complications such as discitis , nerve damage , or bleeding caused by pn applications were observed in the patients . \n one of the most important structures that cause back pain is the intervertebral discs located between the 2 vertebral corpuses . \n intervertebral discs , which play an important role in carrying the load on the low back mechanically , are made up of 2 parts . \n the outer part with a thick structure is called the annulus fibrosus , and the inner part of the structure with gel consistency is called the nucleus pulposus . \n the nucleus pulposus , responsible for carrying 72% of the axial load on the disc , is comprised of 7090% water . here , the most important support is the proteoglycan in the nucleus pulposus . \n durability of the intervertebral disc depends on the fluid exchange and balance of proteoglycan synthesis and breakdown in the matrix . \n when these components decrease , axial load is transferred to the annulus fibrosus and posterior elements of the vertebra . \n while open surgery is the best option for extrusion and sequestration , it has been observed that open surgery is not a good option for contained protrusions . \n when complications that develop due to open surgery have been taken into consideration , the general trend has been toward reductionism and minimalism in spinal surgery . \n many factors play a role , such as the surgeon s desire to decrease operation - related complications , the patient s awareness about new treatment methods , and the development of new technologies . \n all percutaneous decompression techniques are based on the principle that a small volume decrease in the disc , which is a closed area , will result in great pressure decrease in the disc . \n percutaneous disc decompression methods were first used in 1963 with the chemonucleolysis developed by smith . in this method , \n chymopapain , which is a proteolytic enzyme , is percutaneously injected into the disc , and the nucleus melts in an enzymatic fashion . \n unfortunately , severe complications were revealed for chemonucleolysis , the success rate of which was initially shown to be around 80% through double - blind , randomized studies . \n anaphylactic shock , and paresis and plegia that develop due to uncontrolled distribution of the enzyme given to the spinal cord , dural sac and spinal roots , are the most important complications . \n this method , with a 68% reported success rate , was followed by percutaneous automatic lumbar discectomy developed by onik and maron in 1984 ; however , this latter application was not in demand due to its high cost and cumbersome equipment . \n discectomy through disc laser application was first used by choy in 1987 , and 75% successful results were reported . \n however , it has several disadvantages such as costly equipment , inability to visualize the tip of the light beam under fluoroscopy , possibility of spinal damage , severe intraoperative pain , and postoperative low back pain and spasm . \n the pn method introduced in year 2000 is a relatively new method , in which a volume decrease is provided through evaporation depending on molecular degradation in the disc by using radiofrequency energy . through this application , which is defined as controlled ablation ( coblation ) , \n tissue removed through conventional methods actually also results in a slight downgrade in disc bulging , yet it results in height loss in the disc and triggers disc degeneration , whereas removing only a small part from the disc via pn prevents the development of progressive disc degeneration . \n studies conducted on pig cadavers reveal that pn does not cause a clear thermal injury in surrounding annulus fibrosus , vertebral end plates , and spinal cord or nerve roots . in 2007 ; however , it was reported to develop epidural fibrosus following nucleoplasty . \n another study conducted on human cadavers demonstrated that lethal thermal damage might develop outside the nucleus pulposus due to misplacement of the radio frequency probe , but other studies showed that pn was safe , with very little complication risk [ 3336 ] . in many studies \n researchers have investigated the impact of pn on discogenic pain , whether or not accompanied by radicular pain . \n a critical question that needs to be addressed at this point is for what type of back pain pn would provide an effective treatment . \n a systematic review , published in 2009 , illustrated level ii-3 evidence for pn in treatment of leg pain . \n however , this review also demonstrated that there was no evidence available for pn in managing axial low back pain . \n supported the same opinion and asserted that open surgery in discogenic pain would be a better option . \n pn application causes nearly 1 ml volume loss in nucleus pulposus due to tissue destruction , collagen denaturation and contraction . \n it is believed that regression develops in bulging and protrusion due to the abovementioned volume loss . \n yet a study published by calisaneller et al . in 2007 demonstrated that no change , positive or negative , was shown in mris repeated 24 hours after the pn . \n however , masala et al . emphasized that improvement was recorded in parallel with clinical recovery in 80% of control mris repeated 1 year after pn . \n patients with isolated discogenic back pain not accompanied by radicular leg pain were excluded from the study . \n we believe that pn is more effective in radicular pain , therefore only patients with disc herniations accompanying radicular pain were included to the study . \n patients over 60 years of age were not included in our study since old age causes vulnerability for disc degeneration , and could decrease the possibility of benefiting from pn . \n because of our strict exclusion and inclusion criteria , the average vas scores of our patients dropped from 8.71.1 to 3.41.9 at 24 months . \n furthermore , the ratio of our patients reporting 30% decrease in their pain was 87.5% at the latest follow - up . \n statistically significant results were also recorded in odi scores used to evaluate physical recovery . while the average odi score of our patients before the procedure was 76.110.2 , it dropped to 33.914.9 at the end of 2 years . during the last control 48 out of 56 patients ( 85.7% ) recorded improvement in their physical functions when compared to the initial values . in a study comparing percutaneous endoscopic laser discectomy ( peld ) with chemonucleolysis ( cn ) and automated percutaneous lumbar discectomy ( apld ) , \n 300 patients were followed postoperatively for 1 year , with physical examination , postoperative plain lumbosacral radiography , ct , mri and a self - assessment questionnaire . of the patients in the peld group , 68% of considered the outcome as excellent or good and 23% as fair ; the corresponding figures were 55% and 27% in the cn group , and 48% and 32% in the apld group . \n nine percent of the patients in the peld group underwent open microdiscectomy or were suffering from back pain with sciatica , compared with 18% in the cn group and 20% in the apld group . in our study , the percentage of patients stating good and excellent was 66% ( 23 persons ) on the last follow - up . \n future studies should aim to compare the long - term results of different percutaneous decompression methods , including pn \n . limitations of this study include that it was not rct , it included a relatively small number of patients , and the latest follow - up was not conducted with a control mri \n . however , we believe that it is an advantage for this study to have a long follow - up period . \n pn is a safe method and its effectiveness continues at the end of 2 years . at the same time , more rcts are warranted .", "role": "user" }, { "content": "summarybackgroundover the last several decades there has been a general trend toward reduction and minimalization in surgical treatment of chronic back pain , since open surgery brings complications in small and contained disc herniations instead of achieving expected success . \n attention has been focussed on percutaneous nucleoplasty due to the limited success of other minimally invasive methods , as well due to their associated complications . \n however , there have been few studies in the english literature with a follow - up period of more than 1 year.material/methodspatients with chronic disc herniations having more significant radicular leg pain , who did not respond to non - invasive treatment methods and for whom open surgery was not an option were selected for percutaneous nucleoplasty application . upon intervention \n , patients were prospectively questioned by an independent physician regarding pain , physical improvement , and operation satisfaction at 1 , 6 , 12 and 24 months . \n pain was evaluated with vas , and physical improvement was evaluated based on the oswestry disability index.resultsmean vas that was 8.71.1 before the procedure was determined to be 3.41.9 at 24 months follow - up . at the latest follow - up , 87.5% of the patients reported a 30% or higher decrease in their pain . \n while oswestry scores were 76.110.2 in the beginning , they went down to 33.914.9 at the end of 2 years . \n the percent of those stating \n good and excellent satisfaction was 66% ( 23 persons ) on the last follow-up.conclusionswhile it is once more shown that nucleoplasty is a safe method , it is also shown that its effectiveness continues at the end of 2 years .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: discovered by berzelius in 1817 , selenium ( se ) belongs to the 16 group ( formerly group 6a ) in the periodic table , together with oxygen , sulfur , tellurium , and polonium ( nogueira and rocha 2011 ) . \n initially , se was considered only as a toxic element , but for several decades it has been known as an essential trace element associated with significant health benefits in humans and mammals ( schwarz and foltz 1958 ) . the basic role of se activity is its presence in catalytic sites of various selenoproteins . in eukaryotic cells , se can be incorporated into 25 human and 24 rodent selenoproteins during translation , as selenocysteine ( sec ) , 21st aminoacid , which is unique for essential trace elements incorporation ( hesketh 2008 ) . \n selenoproteins may perform various functions in humans , including antioxidant action ( e.g. , glutathione peroxidases ) , transport and storage of se ( selenoprotein p ) , redox signaling ( thioredoxin reductases ) , thyroid hormone metabolism ( iodothyronine deiodinases ) , protein folding ( e.g. , selenoprotein 15 kda ) , and others ( table 1).table 1human selenoproteinsfunctionabbreviationsselenoproteincellular ; tissue localizationantioxidant enzymesgpx1cytosolic glutathione peroxidase ( gpx)cytosol , mitochondria ; widely expressedgpx2gastrointestinal gpxcytosol , er ; gastrointestinal tissue , livergpx3plasma gpxsecreted ; plasma , extracellular fluid , liver , kidney , heart , lung , thyroid , gastrointestinal tissue , breastgpx4phospholipid hydroperoxide gpxcytosol , mitochondria , nucleus ; widely expressed , testesgpx6olfactory gpxunknown ; embryo and oilfactory epitheliumselkselenoprotein ker , membrane proteinselrselenoprotein r ; methionine sulfoxide reductase b1cytosol , nucleus ; widely expressedselwselenoprotein wcytosol ; widely expressed , brain , colon , heart , skeletal muscle , prostatetransport and storage of sesepp1selenoprotein psecreted , cytosol ; plasma , widely expressed , brain , liver , testesredox signalingtrxr1thioredoxin reductase , type icytosol , nucleus ; widely distributedtrxr2thioredoxin reductase , type iimitochondria ; widely distributedtrxr3thioredoxin reductase , type iiicytosol , er , nucleus ; testis - specificthyroid hormone metabolismdio1iodothyronine deiodinase , type imembrane protein ; kidney , liver , thyroid , brown adipose tissuedio2iodothyronine deiodinase , type iier , membrane protein ; thyroid , central nervous system , brown adipose tissue , skeletal muscledio3iodothyronine deiodinase , type iiimembrane protein ; placenta , central nervous system , fetusprotein foldingsep15selenoprotein 15 kdaer lumenselnselenoprotein ner membrane ; widely expressedselmselenoprotein mer lumenselsselenoprotein ser , membrane protein ; widely expressedsec synthesissps2selenophosphate synthetasecytosolunknownselhselenoprotein hnucleus ; widely expressedseliselenoprotein itransmembraneseloselenoprotein ounknownseltselenoprotein ter membraneselvselenoprotein vtestesadapted from papp et al . \n ( 2010 ) genetic polymorphism associated with cancer the role of se and selenoproteins in human health and diseases has been intensively studied with special attention on the determination of relevant biomarkers of se status . \n , se is largely found in animal foods , and to a lesser extent also in plants , which indicates large individual differences in se intake , associated with dietary menu composition , but also with the origin of food , which can be grown ( plants ) or bred ( animals ) on soils with different se content ( gromadzinska et al . 2008 ) . in humans , dietary se intakes also vary geographically from low to high se areas . \n well documented se deficiency health effects keshan and kashin - beck ( kbd ) diseases , associated with muscle disorders , were found in a broad zone running from northeast to southwest china , from the border of heilongjiang to the yunnan province , where concentration of se in the soil was very low ( oldfield 1999 ) . in european countries , dietary se intake is lower than that observed in usa , mainly due to low se soils . \n recommended dietary intake ( rdi ) value of se for adults in usa and europe is 55 g / day . \n tolerable upper intake level determined by the us food and nutrition board ( nas 2000 ) is 400 g / day , while that determined by the scientific committee on food in europe is 300 g / day ( efsa 2008 ) . \n average intake of se by european population ranges from 27 to 70 g per day ( efsa 2008 ) , which is insufficient to meet the daily requirement . \n clinical signs of marginal se deficiency in europe have not been observed or documented yet . \n however , it should be noted that several groups of healthy individuals may be specially prone to se deficiency , which includes breast - fed neonates , pregnant women , and elderly people ( bellinger et al . \n the relationship between se level and health effects is represented by a u - shaped curve that suggests health pathologies associated with se deficiency as well as its excess ( ip 1998 ; jablonska et al . \n the altered se status resulting from insufficient se intake is very often associated with different diseases , including immune diseases , cardiological diseases , and cancer . on the other hand \n , recent studies have indicated that long - term high dietary se supply seems to be related to the risk of type 2 diabetes , amyotrophic lateral sclerosis , and some types of cancer ( bellinger et al . \n although se levels in blood and blood compartments are easily accessible markers of human se nutritional status , se level itself does not reflect its functional significance . \n plasma or serum se , very often used in various se investigations , reflects rather short - term se status , while platelet , leukocyte , and erythrocyte se reflects its longer - term status . \n two best known selenoprotein biomarkers that have been widely used in discriminating of se status are as follows : plasma selenoprotein p ( sepp1 ) level and plasma glutathione peroxidase ( gpx3 ) activity . in healthy humans , \n plasma se is incorporated as sec in two selenoproteins : sepp1 ( 4070% ) , gpx3 ( 2040% ) , while 610% of se is bound to albumin in the form of selenomethionine , through the replacement of methionine . \n free se accounts for less than 1% of total plasma se ( vincent and forceville 2008 ) . \n these biomarkers generally reflect the major sources of human body se , because gpx3 and sepp1 are the unique secreted selenoproteins . \n gpx3 is mainly synthesized in kidney , where it is produced by the cells of proximal tubular ephitelium and by parietal cells of bowman s capsule and then it is released into the plasma ( gromadzinska et al . \n mammalian sepp1 that contains multiple sec residues ( 10 sec residues in humans and rodents ) is synthesized in liver and then secreted into the blood and transported to other tissues . \n recently , specific apolipoprotein e receptor-2 ( apoer2 ) for sepp1 uptake in brain and testis and apoer2 homolog megalin for sepp1 uptake in kidney proximal tubule epithelial cells were found , suggesting receptor - mediated uptake of se in these organs ( burk and hill 2009 ) . there is a growing interest in the use of transcripts level as a molecular biomarker with special regard to whole blood . since early 1990s , \n research on this new molecular biomarker of se status has been extended to se studies in rodents , showing prioritization of preservation and degradation of specific selenoprotein mrna under se deficiency and under conditions of adequate and enhanced supply ( bermano et al . 1995 ) . \n the observed hierarchy of the expression of selenoprotein mrna in response to dietary se supply has indicated the order of selenoproteins , some of them dramatically affected under se deficiency or its excess , and others only marginally . \n selenoprotein transcripts analysis in the blood gives an opportunity to obtain genomic fingerprints , in response to se status , but also reflect an impact of genetic polymorphism of selenoproteins . \n in a few recent human studies , selenoprotein gene expression level in circulating human blood leukocytes was used as a longer term se status indicator . \n some other studies have been focused on the role of se incorporation during selenoprotein synthesis under different se dietary status in humans ( pagmantidis et al . 2008 ; ravn - haren et al . \n 2008a , b ; reszka et al . 2009 ; sunde et al . 2008 ) . \n levels of se for optimization of sepp1 concentration and gpx3 activity in plasma have been determined in people living in se - adequate areas . \n however , these biomarkers may be unsuitable under conditions of high se status , because of plateau levels obtained at such concentrations . \n on the other hand , se levels in blood of individuals living in low se areas with low se intake may be insufficient to ensure maximal activity and/or concentration of selenoproteins gpx3 and sepp1 ( thomson 2004 ) . \n therefore , determination of se intake and se status in humans with variable se supply seems to be important in assessing the most sensitive se status biomarkers . in this review \n , we present recent findings regarding molecular se biomarkers , based on rodent and human studies . \n se status measured by serum / plasma se , plasma sepp1 concentration and plasma gpx3 activity may differently respond to se supplementation , which can give information about low , adequate , and high se dietary intake . \n since several years , it has been generally accepted that selenoprotein level and/or activity may be more useful in determining se status than se itself . \n two human selenoproteins , gpx3 , and sepp1 are believed to be good nutritional se biomarkers in humans . \n studies on se - deficient populations showed that full expression of sepp1 required larger intake of se than did gpx3 activity ( xia et al . \n therefore , setting rdi values for se intake was based on their assessment of the amount of se required to achieve optimal activity or two - thirds optimal activity of gpx3 in plasma to meet the requirements of people living in low , adequate , and high se areas ( rayman 2004 ) . \n different chemical forms of dietary se from animal foods and plants , such as selenite , selenocysteine , and selenomethionine , are involved in metabolic pathways to form selenide . \n selenide is then transformed into sec for selenoprotein biosynthesis or may be methylated to the main metabolite \n selenomethionine is a major form of organic selenium in plant foods , similarly like selenium - enriched yeast in se supplements . \n because of different metabolism of se compounds in organism , absorption of se from different organic and inorganic se food sources , and se supplements , their incorporation in selenoprotein and urinary se excretion may vary in humans . \n 2005 ) clearly indicate that se in the form of selenomethionine is more easily absorbed than selenite . \n absorption of se from yeast was greater than this inorganic form but less than selenomethionine . \n interestingly , plasma se seemed to reflect selenomethionine content of yeast but not the other yeast se forms , indicating its effective bioavailability ( burk et al . \n in several populations in suboptimal se areas in europe , china , new zealand , concentration of sepp1 could not reach the plateau because of low se daily intake , suggesting that se nutritional requirements had not been achieved ( xia et al . \n different plateaus reached by plasma gpx3 activity and plasma sepp1 level indicates that the latter is a better indicator of se status in humans , because a larger intake of se has been required for optimized sepp1 concentration than did gpx3 activity ( xia et al . \n in addition to gpx3 activity , plasma sepp1 level may be a suitable se status and se intake biomarker in individuals from low se populations with additional supply of se . \n in populations living in high se areas , e.g. , australia ( queensland ) , usa , and canada ( central states and provinces ) ( oldfield 1999 ) , where gpx3 activity and sepp1 level in plasma can be optimized by dietary se supply , plasma se seems to reflect se status and se intake ( burk et al . \n the unique conserved stem - loop sec insertion sequence ( secis ) in the 3-untranslated region of mammalian selenoprotein mrna is essential for the recognition of uga as a codon for sec . \n sec may be synthesised from different se dietary sources : selenomethionine , selenocysteine or selenite , se compounds which are further metabolized to selenide and then in the presence of selenophosphate synthetase 2 to selenophosphate this process requires specific sec trna[ser]sec , several translation factors like sbp2 , efsec , and others that serve to distinguish between uga codons designated for sec from those terminating translation . \n sec synthesis occurs directly on its sec trna[ser]sec , initially carrying a serine residue , which serves as an acceptor for selenophosphate . \n maturation of sec trna[ser]sec requires methylation , and two isoforms of methylated and unmethylated sec trna[ser]sec are observed . \n se supplementation is known to modulate the relative ratio between these two isoforms and promote the methylation of sec trna[ser]sec . \n ( hatfield and gladyshev 2002 ; hesketh and villette 2002 ; jameson and diamond 2004 ; schomburg and schweizer 2009 ; small - howard and berry 2005 ) . \n it has been observed that the alterations in selenoprotein activity and concentration during se depletion and repletion are accompanied by changes in the mrna level . under severe se deficiency , this microelement \n is accumulated mainly in the brain and endocrine tissues , where elevated expression and activity of phospholipid glutathione peroxidase ( gpx4 ) and thyroxine deiodinase ( dio ) were observed , indicating the biological importance of these selenoproteins ( schomburg and schweizer 2009 ) . according to rodent studies , \n the main selenoproteins that are resistant to dietary se changes are gpx4 and dio ; thioredoxine reductases ( trxr ) and sepp1 are moderately sensitive , while gpx1 , selw , selh are very sensitive to low se supply ( reeves and hoffmann 2009 ; sunde 2010 ) . \n several in vitro and in vivo studies have shown that , under se deficiency , the degradation of selenoprotein mrna occurs through nmd ( nonsense codon - mediated mrna decay ) ( moriarty et al . 1998 ; weiss and sunde 1998 ) . due to specific nucleotide sequences and preferential binding of sbp2 translation factor , \n 14 of 25 human selenoprotein mrnas may be sensitive to nmd - based degradation under low se supply ( squires et al . \n however , a study on rodents , suggesting regulation of selenoprotein expression , irrespective of this hypothetical preference , indicates that also other mechanisms concerning differences in the expression efficiency of some selenoproteins under se deficiency must exist ( sunde et al . 2009 ) . \n in addition , methylated sec trna[ser]sec supports the biosynthesis of selenoproteins gpx1 , gpx3 , selr , selt , sensitive to low se supply , while other selenoproteins , like trxr1 and gpx4 , moderately sensitive and resistant to low se supply , require unmethylated isoform ( schomburg and schweizer 2009 ) . \n an attempt to answer the question whether selenoprotein gene expression may be used as a biomarker of se status was presented for the first time by roger a. sunde s team . \n sepp1 mrna shows the highest expression in rat testes and liver , while gpx3 mrna expression is highest in rat kidney ( evenson et al . \n 2004 ) , which is in agreement with observed selenoprotein activity and protein expression in these organs . \n therefore , these molecular biomarkers may be also useful for the determination of se status as well as for establishing physiological requirements of se for adequate selenoprotein gene expression . \n these authors found also that , in rodents , gpx1 , selh , and selw mrna levels were highly regulated by se status ( sunde 2010 ) . \n analysis of hierarchical regulation of different selenoprotein mrnas by se status indicates that gpx1 transcripts level is the best and adequate molecular biomarker in rats , because dietary se deficiency similarly decreased gpx1 mrna in blood and liver . by way of comparison , decrease in se supply in diet \n gpx1 mrna expression in rat liver was the highest , while in blood , expression of this selenoprotein was at 4th place in tissue rank , comparable with the expression in heart and kidney . \n interestingly , other investigated selenoprotein transcripts also presented distinct expression pattern across the tissues and it was found that gpx1 , gpx3 , gpx4 , sepp1 , trxr1 expression in blood were comparable with those observed in the major organs ( evenson et al . \n regulation of selenoprotein mrna under se dietary deficiency presents diversity , from dramatic decrease in gpx1 mrna to lack of changes for gpx4 mrna . \n low selenoprotein mrna observed in rodents reflect depletion of se supply in the diet , and adequate se supply regulates expression level very efficiently . \n it has been found that at least half of the dietary se necessary to provide plateau for enzymatic activity or protein expression is adequate to provide plateau for mrna expression in liver , muscle , and kidney of rats ( barnes et al . \n , selenoprotein mrna level is expressed as hyperbolic curve presenting plateau breakpoints at low se supply for majority of selenoproteins . \n minimal se requirement for growing rats was 0.1 g se / g diet based on liver se , liver , and rbc gpx1 activity . \n slightly lower dietary se requirements based on plasma gpx3 activity , liver trxr activity , and liver and kidney gpx3 activity were observed . \n based on dose response curves for selenoprotein mrna indifferent tissues , the minimum dietary requirements were lower than for physiological se biomarkers , ranging between 0.04 and 0.06 g se / g diet in liver and kidney and was between 0.03 and 0.05 g se / g diet in muscles . besides , it has been assumed that it is not feasible to use selenoprotein mrna in rat tissues as a biomarker for super - nutritional se level ( up to 0.8 g se / g diet ) . \n these experiments evidently suggest that marginal level of se in diet is able to increase selenoprotein mrna to adequate level in rats and mice , what may suggest common mechanism in regulation of selenoprotein mrna expression by dietary se supply ( barnes et al . \n recently , sunde ( 2010 ) proposed the panel of molecular biomarkers , which could be useful for the assessment of selenium status in rats and might be effective as the traditional biomarker panel in rat tissues . \n gpx1 , gpx3 , selt , and selw mrna panel of transcripts level was significantly correlated with liver se concentration , gpx1 and selk mrna were associated with liver gpx1 activity , while sepw and selk mrna reflected kidney selenium status , and gpx1 , sepw , txnrd1 transcripts level correlated with gpx1 kidney activity . \n interestingly , recent studies suggest that regulation of selenoprotein mrna by se dietary status is not a general phenomenon in rodents . \n it was found that in mice , majority of analyzed selenoprotein transcripts in liver and kidney were not significantly regulated by se deficiency ( sunde et al . \n it has been found that minimum se requirement of the turkey is higher than for rodents ( sunde and hadley 2010 ) . \n dietary requirement was decreased at least 50% in old rats as compared to requirements of young animals ( sunde and thompson 2009 ) . \n expression of the majority of selenoprotein mrna in testis , except for gpx1 , sepp1 , sepw , and also apoer2 , was not regulated by dietary se status ( schriever et al . 2009 ) . \n the mrna abundances of the 12 selenoprotein genes in thyroid and pituitary of young pigs were resistant to increasing se dietary supply in diet and also se deficiency , but not in liver , where nmd under se deficiency was observed for gpx1 , sepw , sepn , txrd1 . \n the testicular mrna of txnrd1 and sep15 were decreased by increasing dietary se supply , indicating that high se status may be associated with a decrease in selenoprotein mrna transcripts level ( zhou et al . \n differences in dietary minimal se supply required for maximal mrna expression and/or selenoenzyme activity suggest differential regulation depending on the type of selenoprotein as well as tissue . \n therefore , findings regarding ranking of different selenoproteins synthesis within tissue and also different distribution of selenoproteins in various tissues should be considered in establishing a universal se status biomarker ( sunde 2010 ) . \n in 2003 , the panel of experts in uk food standards agency has issued specific research recommendations after evaluation of current knowledge regarding the assessment of se status , including further development of functional biomarkers ( elsom et al . \n recently , a special emphasis is laid on the application of population of circulating white blood cells ( wbc ) transcriptome patterns in nutritional studies . \n transcriptomics studies suggest that genes with various functional annotations can be significantly expressed in wbc ( visvikis - siest et al . \n gene expression patterns may be also useful to define biological processes associated with human health and disease . \n however , only a few studies assessing selenoprotein gene expression in various populations of circulating wbc in humans have been conducted so far ( table 2).table 2human studies on selenoprotein molecular biomarkersstudybaseline daily se intake ( g)mean sdbaseline plasma se level ( ng / ml)mean sdselenoprotein gene expression in wbcuk , selgen study , n = 39 , both sexes , 6 week . se intervention ( pagmantidis et al . \n 2008)not presented93.9 1.7lymphocyteup - regulation : sps11.15 ( 1.061.23)selk1.11 ( 1.041.19)sep151.11 ( 1.021.20)denmark , n = 20 , 1840 years . \n . 2008a)49.8 13.6113.2 12.2leukocyteno effect : gpx1 , trxr1 sepp1denmark , precise pilot study , n = 105 , both sexes , up to 5 years . \n 2008b)49.8 13.693 11.2leukocyteno effect : gpx1uk , n = 39 , both sexes , 28 week . \n se intervention ( sunde et al . 2008)48 1489.2 12.5whole bloodno effect and no association between se status and gpx1,gpx3 , gpx4 , sepp1 , sepw , sephpoland , n = 47 healthy men ( reszka et al . \n 2009)24.2 17.4 ( unpublished data)54.3 14.6leukocyteno association between se status and gpx1 , gpx3 , sepp1 , sep15 human studies on selenoprotein molecular biomarkers human studies have not confirmed the hypothesis that selenoprotein transcript level in circulating leukocytes and in whole blood may be the reliable biomarker of se status in population with adequate ( sunde et al . \n 2008 ) and suboptimal ( reszka et al . 2009 ) baseline se level in plasma ( fig . 1 ) . \n after short - term 100 g sodium selenite supplementation , healthy subjects from the selgen population were chosen at random for microarray analysis of rna isolated from lymphocytes . \n the greatest changes after se supplementation were observed for genes that encode proteins functioning in protein biosynthesis . \n up - regulation of selenoprotein k ( selk ) and selenoprotein 15 kda ( sep15 ) after se supplementation was observed , indicating that only a small number of selenoprotein encoding genes was altered by different se dietary supply ( pagmantidis et al . \n ( 2008a , b ) also indicated lack of se impact on selenoprotein mrna expression in wbc after short- and long - term se supplementation . \n after 1 week of supplementation with nonorganic se or organic form among healthy young danish men , there were no differences in mrna expression of gpx1 , trr1 , and sep1 in leukocytes ( ravn - haren et al . \n similarly , after 5 years of se - enriched yeast supplementation of the precise danish subjects , there were no differences in the expression of gpx1 in circulating wbc ( ravn - haren et al . \n moreover , selenoprotein expression level in whole blood was not significantly associated with se status measured in the blood and se supply measured according to dietary questionnaire in uk population ( sunde et al . \n the baseline se level in uk and danish populations was relatively high as compared to other european populations and it approximately averaged 100 ng / ml in plasma ( table 2 ) . \n lack of changes in selenoprotein mrna levels after se supplementation indicates that protein synthesis may already be saturated in leukocytes at such sufficient se concentration . in the small group of 47 healthy polish individuals , \n plasma se levels were below the level required to optimize plasma gpx3 activity ( 54.3 14.6 ng / ml ) . \n however , no relationship between serum se and gpx1 , gpx3 , sepp1 , and sep15 mrna transcripts level , as well as gpx1 and gpx3 activities and selenoprotein mrna expression was found ( reszka et al . \n daily se intake in studied european groups was lower than rdi ( 55 g / day ) for adults in europe and us . \n the observed hyperbolic curve describing the relationship between selenoprotein mrna expression and dietary supply in rodents suggests that suboptimal se status in humans may be sufficient for selenome transcription machinery . \n interestingly , gpx1 , gpx3 , sepp1 , and sep15 selenoprotein mrna expression in circulating blood leukocytes was significantly positively correlated , indicating similar regulation of expression in circulating blood leukocytes . \n although significant correlations were found between several selenoprotein mrnas in the circulating blood leukocytes of healthy individuals , no correlation was found in the blood of bladder cancer patients , which may suggest an alteration of selenoprotein synthesis during carcinogenesis ( reszka et al . \n british ( whole blood ) ( sunde et al . 2008 ) ( a ) and suboptimal polish ( leukocyte ) ( reszka et al . 2009 ) ( c ) se level and correlation between plasma se level and sepp1 transcripts level in population with adequate \n british ( whole blood ) ( b ) and suboptimal polish ( leukocyte ) ( d ) se level a and b reproduced with permission from sunde et al . \n ( 2008 ) correlation between plasma se and gpx3 transcripts level in population with adequate \n british ( whole blood ) ( sunde et al . 2008 ) ( a ) and suboptimal polish ( leukocyte ) ( reszka et al . 2009 ) ( c ) se level and correlation between plasma se level and sepp1 transcripts level in population with adequate \n ( d ) se level a and b reproduced with permission from sunde et al . \n functional significance of blood se status is mainly related to selenoprotein activity in specific tissues . therefore \n , both traditional and molecular biomarkers of se status measured in different human tissues , except for controlled se intake , may depend on additional major modifiers , like health status ( e.g. , endocrine and immunological status ) , inter - individual variations ( age , sex , genetic polymorphism ) , environmental exposure , diet , medication , etc . \n therefore , establishing the se status and intake which would be optimal for human health seems to be very difficult , especially in many populations experiencing suboptimal se supply , including europe . \n epidemiological and animal studies clearly indicate that biological effects of se are sex - specific , which may be associated with endocrine regulation and also immunological status . \n it has been suggested that cancer risk in men is more profoundly influenced by se status than in women ( waters et al . \n selenoprotein gene expression displays sexual dimorphism in various organs of females and males , e.g. , se status was linked to male fertility due to gpx4 function during spermatogenesis ( schomburg and schweizer 2009 ) \n . sex - specific selenoprotein expression pattern may vary or be sustained with age . in the selgen study , an effect of se supplementation was associated with gpx4 genetic polymorphism in a sex - specific manner ( meplan et al . \n plasma se level is not likely to accurately reflect tissue se status or selenoenzyme activity and level . \n 2006 ) . se metabolism may be altered in different health pathologies , e.g. , in patients with inflammatory diseases . during critical illness , like sepsis , acute phase response , and other immunological disturbances \n , serum se status may be lower and insufficient to support organ function . in systemic inflammatory response syndrome patients , \n serum se concentration was significantly lower ( vincent and forceville 2008 ) . tobacco smoking or occupational exposure can also increase dietary requirement of se . \n it is generally agreed that smoking can decrease the activity of antioxidative selenoproteins , probably due to formation of complexes of se with cadmium ( ellingsen et al . \n a scheme of traditional and molecular biomarkers measurements with the impact of potential modifiers ( physiological , environmental , genetic ) . \n the optimal selenium biomarker should reflect all putative egzo- and endogenous factors which can modulate selenium bioavailability , metabolism and selenoprotein transcription , biosynthesis , transport , activity and function . \n a type of measurement used for the determination of selenium status should be also considered biomarkers of selenium status in humans . \n a scheme of traditional and molecular biomarkers measurements with the impact of potential modifiers ( physiological , environmental , genetic ) . \n the optimal selenium biomarker should reflect all putative egzo- and endogenous factors which can modulate selenium bioavailability , metabolism and selenoprotein transcription , biosynthesis , transport , activity and function . \n a type of measurement used for the determination of selenium status should be also considered in human population , there is a large individual variation in response to se supplementation , appearing to be unrelated with the baseline se status ( brown et al . \n recent human studies indicate that selenium status , measured as body se , as well as sepp1 plasma level and gpx activity , may be significantly influenced by genetic polymorphism of specific selenoproteins , including gpx1 ( rs1050450 ) ( jablonska et al . \n 2007 , 2009 ) , gpx4 ( rs713041 ) ( meplan et al . 2008 ) . \n the impact of sepp1 variations in codon 234 , associated with ala to thr change ( rs3877899 ) and g to a transition within 3 untranslated region ( utr ) of sepp1 mrna ( rs7579 ) , resulted in the alteration of se status before as well as after se supplementation ( meplan et al . \n . these polymorphisms also influence proportion of two sepp1 50 and 60 kda isoforms in plasma , which was proposed as the modulation factor of se incorporation during selenoprotein synthesis ( meplan et al . 2009 ) . \n se availability modulated by sepp1 variants , resulting in difference in isoform pattern was restricted just to males . \n interestingly , a possible impact of gender was observed for functional significance of gpx4 genetic polymorphism . \n single nucleotide polymorphism in 3-utr of gpx4 mrna , associated with c to t change ( rs713041 ) influenced the level of gpx4 in lymphocytes , and also other selenoproteins ; however , this effect was more evident in females ( meplan et al . \n one may hypothesize that separate molecular mechanisms for gpx4 synthesis in testes and high dietary se requirements in males override genetic polymorphism in gpx4 and sepp1 . \n recent findings suggest also that the association between gpx1 activity and se concentration , analyzed separately for each gpx1 pro198leu ( rs1050450 ) genotype group , was the highest for pro / pro and the lowest for leu / leu genotype , suggesting different response of gpx1 activity to se . \n this also points to the importance of the genetic background in the assessment of the se status with the use of selenoprotein biomarkers such as gpx1 activity ( jablonska et al . \n adaptation of humans to suboptimal dietary se supply with low se level was observed by finley et al . \n ( 1999 ) in healthy study participants living in new zealand , where people consume less se than suggested by the rdi of 55 g / day . \n se level in blood of individuals living in low se areas and with low se intake may be insufficient for maximal activity of gpx3 and level of sepp1 in plasma . however , supplementation had no effect on se status in platelets and erythrocytes , which can be regarded as indicative of long - term se intake . \n interestingly , high retention of stable se isotope in placebo individuals was observed as compared to individuals supplemented with 30 g se daily for 5 months , suggesting maintenance of critical se pool in the human body and adaptation to low se status by adjusting of its secretion . \n therefore , physiological requirements of se are lower than recommended in humans , but enabling selenoprotein synthesis . besides , \n in patients with diseases like kbd and cancer , where low se level in blood is observed , down - regulation of specific selenoprotein gene expression was found to occur in circulating wbc \n . significant down - regulation of sepp1 mrna level was observed in han chinese with kbd ( sun et al . 2010 ) . in caucasian bladder cancer \n male patients , sepp1 , gpx1 , gpx3 , sep15 mrna levels were lower than in the control group ( reszka et al . \n preferential incorporation of sec into selenoprotein mrna in circulating blood leukocytes under relatively low se supply merits investigations intended to identify potential sensitive and resistant selenoproteins under se deficiency in humans . \n while the levels of se required for optimization of sepp1 and gpx3 activities in plasma are well known , estimating se level that is required for maximal selenoprotein gene expression in humans requires further research . according to rodents studies and studies among humans , which have been discussed in this review \n , it appears that suboptimal se intake may be sufficient to achieve selenoprotein mrna expression and molecular requirements of se are lower than the established recommended dietary intake in humans55 g / day ( efsa 2008 ; nas 2000 ) . \n it should be noted that the expression of individual selenoprotein mrna may be not always linked with protein expression . \n therefore , since we have not understood the transcriptional and translational link of selenoprotein under different se supply in different human tissues , biological functionality of selenoprotein could be recognized only at protein level . \n preferential incorporation of se into selenoproteins in rodents was observed even at suboptimal dietary se level . in rats , \n minimum se requirements for achieving a plateau of selenoprotein mrna expression have been low , reached plateau at half of the dietary se concentration required for maximal activity of gpx1 , gpx3 , and maximal level of sepp1 in different tissues ( barnes et al . \n therefore , in rodents , selenoprotein mrna expression does not seem to be a good indicator for se status . \n hypothetically , in almost all populations , even in those with low and moderate se intake and se level in blood compartments , selenoprotein encoding gene expression might reach the plateau levels and serve as a sensitive functional biomarker of se status . \n however , it should be noted that regulation of selenoprotein gene expression , metabolic pathways , and responses to se interventions in animals may differ from those in humans . \n none of the human studies conducted so far has indicated that selenoprotein mrna in the whole blood and blood cells may be a good indicator of se status in humans ( pagmantidis et al . \n . low se status may be adequate for proper regulation of selenoprotein transcription , but not for proper physiological activity of selenoproteins . \n preferential incorporation of se into selenoprotein and its optimal saturation at low dietary se level does not provide adequate activities and selenoprotein expression in different tissues . \n therefore , it may be suggested that functional rather than molecular biomarkers of se are optimal indicators of its supply . \n it seems reasonable to conclude that sepp1 concentration in plasma may clearly indicate sub - optimal to optimal se supply , because it can reflects functional significance of se activity in organism . in over - optimal se supply , \n where sepp1 level is optimized , plasma se seems to reflect se intake and achieved se status . \n all possible modifiers of se status determined by means of biochemical and molecular techniques , including smoking , occupational exposure , diet , health parameters , sex , age , endocrine and immunological status , should be included , as these factors can potentially modulate selenoprotein gene expression . \n impact of polymorphism of selenoproteins should be also included in complete analysis of se requirements of individuals with different genotypes and haplotypes . \n therefore , comprehensive intervention studies of circulating leukocyte selenoprotein transcript levels in a population with suboptimal and with adequate compared to over - optimal selenium status should be conducted .", "role": "user" }, { "content": "the most commonly used methods for assessing the selenium ( se ) status in humans involve analysis of se concentration , selenoprotein activity , and concentration in the blood and its compartments . \n recently , it has been suggested that the expression of selenoprotein mrna in circulating blood leukocytes could differently reflect se status , due to prioritization of specific selenoprotein synthesis in response to dietary se supply . whereas the se levels required for optimization of selenoprotein p level and plasma glutathione peroxidise activity are well known , \n estimation of se level that is required for maximal mrna expression of selenoprotein in humans is the subject of current investigations . \n studies on rats suggest that whole blood selenoprotein mrna level can be used as the relevant molecular biomarker for assessing se status , and suboptimal se intake may be sufficient to achieve effective expression . \n human studies , however , did not confirm this hypothesis . according to studies on rodents and humans discussed in this review \n , it appears that suboptimal se intake may be sufficient to satisfy molecular requirements of se and it is lower than current recommended dietary intake in humans . the use of selenoprotein transcripts as a molecular biomarker of se status requires further studies on a large group of healthy individuals with different baseline se , including data regarding genetic polymorphism of selenoproteins and data regarding potential modifiers of se metabolism .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: \n \n the online version of this article ( doi:10.1007/s00125 - 009 - 1592 - 4 ) contains supplementary material , which is available to authorised users . \n type 2 diabetes mellitus and its common complication , peripheral neuropathy , affect a large population [ 1 , 2 ] . \n peripheral neuropathy leads to sensory and motor deficits , which often result in mobility - related dysfunction , alterations in gait characteristics [ 3 , 4 ] and balance impairments [ 5 , 6 ] . \n diabetic patients with peripheral neuropathy have lower gait velocity , decreased cadence , shorter stride length , increased stance time and higher step to step variability compared with healthy controls . \n moreover , these patients have less ankle moment and ankle power [ 7 , 8 ] , as well as a different onset and cessation time of muscle activity compared with healthy controls . \n patients present more co - contractions of agonist and antagonist muscles at the ankle and knee joints during stance phase . \n speculate that the co - contraction mechanism may enable these individuals to adopt a safer , more stable gait pattern to compensate for diminished sensory information . \n the same authors have reported reduced ankle strength and mobility , which they considered to be the primary factors contributing to gait alterations . \n allet et al . have also found lower limb strength , fear of falling and sensory problems to be related to spatiotemporal gait alterations . \n additionally , individuals with peripheral neuropathy show postural instability with a larger centre of pressure displacement , higher sway area and greater instability when standing still with eyes closed . \n in addition to these gait and balance impairments , diabetic patients are known to suffer from increased risk of injurious falls . \n fall - related injuries are often assumed to trigger a vicious circle because of their potentially detrimental influence on the physical activity levels of affected patients . \n public health guidelines for diabetes management recommend that patients perform at least 30 min of physical activity a day six times a week , requiring adequate gait security and balance . \n however , little is known about treatment strategies that could improve patients gait and balance , thereby also reducing the risk of falls . although there is evidence that an exercise regimen improves clinical measures of balance in patients with peripheral neuropathy , clinical trials investigating the gait of diabetic individuals generally focus on increased foot pressure , another major problem in this population and related to the high risk of ulcers in such patients . \n only few studies have evaluated treatments that aim to improve gait and balance and decrease fall risk [ 16 , 17 ] . \n tested an insulin sensitiser , rosiglitazone , which promises to reverse some of the circulatory impairments seen in diabetes , thereby improving patients gait . \n they reported encouraging results after administering rosiglitazone ( decreased step width , reduced reaction time and less acceleration at the joints ) . \n however , rosiglitazone was recently associated with increased risk of myocardial infarction and death from cardiovascular incidents . \n evaluating patients with various form of peripheral neuropathy ( 30 of 42 of whom had diabetic peripheral neuropathy ) , found that the use of a cane , ankle orthoses or touching a wall improved step - width range , step - time variability and speed while walking under challenging conditions . \n and orr et al . have investigated the effect of a specific physical training programme not only on the activity level and quality of life of diabetic patients , but also on their habitual and maximal walking speed . however , both studies seem to have evaluated the same group of participants . in these studies , the effect of a \n tai chi for diabetes programme ( twice a week for 16 weeks ) on gait , balance , musculoskeletal and cardiovascular fitness , self - reported activity and quality of life was compared with that of sham exercises . \n nevertheless , several studies [ 2123 ] have shown positive training effects on gait speed , postural stability and mobility of elderly individuals . \n additionally , a meta - analysis evaluating fall prevention studies for the elderly showed a 4% decrease in the fall - rate of individuals who were in a treatment group . \n since elderly people often show symptoms similar to those in diabetic patients ( i.e. de - conditioning , muscle weakness , decreased joint mobility and decreased foot sensibility ) , we assumed that programmes developed for the elderly might also improve gait and balance of diabetic patients . \n thus , this study aimed to evaluate the effect of a specific training programme , which was based on previously elaborated core components of successful fall prevention programmes for the elderly , on the gait and balance of diabetic patients . \n gait speed and coefficient of variation of gait cycle time ( cvgct ) were selected as primary outcomes because they have been shown to be related to increased risk of falls [ 22 , 26 ] ( slow gait speed and high cvgct indicate increased fall risk ) . \n balance control , muscle strength and joint mobility are also important fall risk factors that may be influenced by exercise . for these reasons , they were chosen as secondary outcomes . \n fear of falls is a cognitive behavioural component , which was recently shown to be related to the gait velocity of diabetic patients . \n we hypothesised that diabetic patients participating in a training programme would significantly improve their walking speed and gait variability ( cvgct ) . \n we further assumed that such patients would significantly : ( 1 ) improve their balance ; ( 2 ) increase their lower limb strength ( in particular hip extensors , knee extensors and ankle flexors ) ; ( 3 ) increase their ankle joint mobility ; and ( 4 ) decrease their fear of falling . \n study design this randomised controlled prospective trial with two arms ( intervention group and control group ) was conducted at the university hospital of geneva , switzerland . \n the study was approved by the local ethics committee.a sample of 71 diabetic patients was recruited from patients consulting either the service of therapeutic education for chronic diseases or the service of endocrinology at the university hospital in geneva . of these \n , 35 patients were allocated to the intervention group and 36 to the control group . \n patients were included if they were medically diagnosed with type 2 diabetes ( fasting blood sugar 7 mmol / l ) . only patients without medical contraindications for engaging in physical activity and with a clinically diagnosed neuropathy \n clinically diagnosed neuropathy was evaluated on the basis of a vibration perception threshold of 4 with a rydel \n patients were requested to indicate when they could no longer feel the vibration . at this point \n the investigator rated the vibration on a 9-point scale ( 0 = severe neuropathy ; 8 = no neuropathy ) . \n exclusion criteria were : patients with concomitant foot ulcers , orthopaedic or surgical problems affecting gait variables , non - diabetic neuropathy ( due to charcot \n marie tooth disease or alcohol ) , other neurological pathologies ( other than peripheral neuropathy ) that could influence gait variables or inability to walk a minimum of 500 m without a walking aid.training programmes started as soon as enough patients ( 20 to 28 per group ) had been recruited , i.e. in september 2007 , january 2008 and april 2008 . \n for each of these starting points a new randomisation list was electronically generated and was used by a person not involved in the recruitment , evaluation or treatment processes . \n each list ensured equal distribution over groups.all eligible patients identified by the medical staff were asked to participate . \n they were informed that if willing to participate , they would be randomly assigned to an intervention group or control group . \n patients who agreed to join the study were contacted by the study coordinator for an individual appointment , at which the informed consent document was signed and baseline evaluation performed . \n after this initial appointment , during which patients underwent a clinical examination , a gait analysis and both static and dynamic balance tests , and also filled in a fear of falls questionnaire , patients were randomly allocated to the intervention group or to the control group . \n all outcome measures were assessed at baseline , after 12 weeks and after 6 months by the same experienced physiotherapist each time.patients allocated to the intervention group received a timetable containing all planned sessions over 12 weeks . \n however , the nature of the study made it impossible to blind patients and therapists . \n the assessor was kept as much as possible unaware of the group assignment . however , as she worked in this hospital during the experiment , she saw some patients arriving for training sessions.after the 12 week programme patients were encouraged to continue with the learned exercises during the next 6 months . \n test description and measures prior to the clinical examination , the physiotherapist checked the vibration perception threshold with the tuning fork . \n maximum isometric strength of the hip , knee , ankle flexors and extensors was then measured with a hand - held dynamometer ( microfet ; hoggan health industries , inc . , west \n joint mobility of the hip and both knee and ankle flexion and extension were measured with a manual goniometer . \n patients worry of falling when performing different activities was assessed with the falls efficacy scale international ( fes - i ) . \n afterwards patients underwent the following functional tests : \n performance - oriented mobility assessment ( poma ) , which scores 16 items ( nine for evaluation of balance , seven for assessment of gait).outdoor gait assessment recorded with a device ( physilog ; bioagm , lausanne , switzerland ) . \n participants were asked to walk , wearing four miniature gyroscopes ( adxrs 250 analogue device ) attached to both shanks and thighs with velcro straps , on a specific walkway at their preferred walking speed . \n the walkway consisted of two 50 m tarred pathways , two 50 m grass pathways and two 20 m cobblestone pathways in the hospital s backyard . for this study \n a detailed description of this gait assessment has been published elsewhere .dynamic balance test in which participants had to walk as fast and as precisely as possible on a 5 m beam ( 15 cm high , 15 cm wide ) . \n patients had one practice trial before the test started . if a patient had to step off the beam he or she was allowed to do the test again . in the event that this patient stepped off the beam again , he or she was asked to resume the exercise at the stepping off point , continuing from there to finish the test.static balance test evaluating postural control by means of a device ( biodex balance system ; biodex medical systems , new york , usa ) . \n the level of difficulty while standing on this platform can be manipulated by altering the resistance of the platform to deviations . \n the balance test is most difficult when the platform provides the least resistance to tilting and is therefore the least stable . \n each participant stands barefoot on the platform and performs two different tests ( level 8 = easiest level , level 6 = a more difficult level ) . \n the foot position was standardised using a pre - formed triangle ( heels together with feet forming an angle of 20 degrees ) . \n they were permitted to touch handrails , but only to re - establish balance during extreme postural deviations . \n the participants were then instructed to find a position at which they could maintain platform stability . \n each recording lasted for 60 s with a 60 s rest between each trial . \n we used a single recording per test condition and only one attempt per condition to reduce fatigue . \n all tests were done at baseline , after the 12 weeks intervention and at 6 months after the intervention . \n a balance index was calculated using the time and deviation ( in degrees ) of the platform away from a level position . \n performance - oriented mobility assessment ( poma ) , which scores 16 items ( nine for evaluation of balance , seven for assessment of gait ) . \n outdoor gait assessment recorded with a device ( physilog ; bioagm , lausanne , switzerland ) . \n participants were asked to walk , wearing four miniature gyroscopes ( adxrs 250 analogue device ) attached to both shanks and thighs with velcro straps , on a specific walkway at their preferred walking speed . \n the walkway consisted of two 50 m tarred pathways , two 50 m grass pathways and two 20 m cobblestone pathways in the hospital s backyard . for this study only the tarred terrain was evaluated . \n dynamic balance test in which participants had to walk as fast and as precisely as possible on a 5 m beam ( 15 cm high , 15 cm wide ) . \n if a patient had to step off the beam he or she was allowed to do the test again . in the event that this patient stepped off the beam again , he or she was asked to resume the exercise at the stepping off point , continuing from there to finish the test . \n static balance test evaluating postural control by means of a device ( biodex balance system ; biodex medical systems , new york , usa ) . \n the level of difficulty while standing on this platform can be manipulated by altering the resistance of the platform to deviations . \n the balance test is most difficult when the platform provides the least resistance to tilting and is therefore the least stable . \n each participant stands barefoot on the platform and performs two different tests ( level 8 = easiest level , level 6 = a more difficult level ) . \n the foot position was standardised using a pre - formed triangle ( heels together with feet forming an angle of 20 degrees ) . \n they were permitted to touch handrails , but only to re - establish balance during extreme postural deviations . once in this position , \n the participants were then instructed to find a position at which they could maintain platform stability . \n each recording lasted for 60 s with a 60 s rest between each trial . \n we used a single recording per test condition and only one attempt per condition to reduce fatigue . \n all tests were done at baseline , after the 12 weeks intervention and at 6 months after the intervention . \n a balance index was calculated using the time and deviation ( in degrees ) of the platform away from a level position . \n treatment description the training took place twice a week for 60 min over 12 weeks . \n this intensity was chosen on the basis of previously developed successful interventions in pre - frail elderly persons [ 25 , 3638 ] . \n each session was conducted in groups ( five to eight participants ) in order to promote long - term participation . \n four different physiotherapists and four assistants were trained to direct the sessions in order to guarantee continuity . a session consisted of a warm up ( 5 min ) , followed by a circuit training ( 40 min ) including gait and balance exercises . \n balance and walking tasks ( stance on heel / toes , tandem stance , one leg stance , different kinds of walking ) alternated with functional strength and endurance exercises ( sitting to standing , walking up and down a slope , stair climbing and mini hops ) . \n each task was carried out twice for 1 min each time , and the complexity of the task could be progressively increased , e.g. changing from stable to unstable surfaces ( wobble board ) , increasing step height . \n sessions were completed with interactive games ( e.g. badminton , obstacle race in teams ) ( 10 min ) and a short feedback session with suggestions for individual home exercises ( 5 min ) . as currently no specific gait and balance programme \n is offered to diabetic patients , the control group received neither treatment nor specific advice . \n both the intervention group and control group were allowed to continue their usual leisure activities . \n sample size calculation in previous studies , gait velocity of diabetic patients was 1.25 0.19 m / s compared with 1.45 0.14 m / s in a healthy control group . allowing that diabetic patients might improve their mean speed from 1.25 m / s to 1.35 m / s , 64 patients were needed to have an 80% probability that the study would detect a treatment difference at a two sided 5% level of significance . \n a 10% drop - out rate was hypothesised and therefore we aimed to include 71 patients in total . \n data analysis statistical analyses were performed using spss version 15 for windows ( spss , chicago , il , usa ) . \n the outcomes at 12 weeks ( i.e. post - treatment ) and 6 months were dependent variables . the intervention allocation was considered to be a dichotomous independent variable in the analysis . \n the baseline values of the outcome measures were incorporated in the linear regression model as covariates.to reduce the risk of type i error , a bonferroni corrected alpha level of p = 0.0026 ( alpha divided by number of tests per follow - up ) was used to determine a significant difference between groups . however , to allow identification of areas of interest for future investigations and to reduce the risk of type ii errors , the results are presented with the corrected ( p = 0.0026 ) and uncorrected ( p = 0.05 ) significance levels . \n an intention to treat analysis was performed and in the event of missing values for any variables , these values were imputed by means of the last observation carried forward method . \n this clinical trial is closed to recruitment and closed to follow - up . the flow chart ( fig . \n 1 ) provides a detailed description of drop - outs and loss to follow - up , as well as the number of participants analysed in each group . \n descriptive statistics show patients characteristics ( table 1 ) and illustrate the improvement of the intervention group in all variables post - intervention ( electronic supplementary material [ esm ] table 1 ; fig . 2 ) . \n two patients developed pain in their achilles tendon , obliging us to slow down the progression for \n intervention group participants partially lost their treatment benefit in the 6 months of follow - up , but their performance level remained superior to that at baseline . \n 1flow chart with detailed description of recruitment , number of drop - outs and reasons for not continuing . \n the flow chart is based on the consort statement recommendations in a previous publication table 1description of patients baseline characteristicsbaseline evaluationintervention groupcontrol groupage ( years)63 ( 7.99)64 ( 8.89)bmi ( kg / m)30.46 ( 6.03)31.46 ( 5.25)falls in 12 months ( n)0.71 ( 1.07)0.45 ( 0.89)test with tuning fork3.23 ( 1.26)3.32 ( 1.32)height ( cm)166.14 ( 8.5)168.56 ( 8.64)weight ( kg)83.62 ( 16.56)89.17 ( 12.33)values are mean ( sd)a fall was defined as an unexpected event in which the participant comes to rest on the ground , floor or lower levelscale 08fig . 2plots illustrating the baseline difference of ( a ) gait speed , ( b ) cvgct , ( c ) poma score , ( d ) time to walk over a beam , ( e ) biodex sway index ( level 6 ) and ( f ) fear of falls for each group at baseline ( ba ) , after the intervention ( pi ) and at the 6-month follow - up ( fu ) . values are adjusted mean and 95% \n white squares and dotted line , control group ; black circles and continuous line , intervention group flow chart with detailed description of recruitment , number of drop - outs and reasons for not continuing . \n the flow chart is based on the consort statement recommendations in a previous publication description of patients baseline characteristics a fall was defined as an unexpected event in which the participant comes to rest on the ground , floor or lower level plots illustrating the baseline difference of ( a ) gait speed , ( b ) cvgct , ( c ) poma score , ( d ) time to walk over a beam , ( e ) biodex sway index ( level 6 ) and ( f ) fear of falls for each group at baseline ( ba ) , after the intervention ( pi ) and at the 6-month follow - up ( fu ) . \n white squares and dotted line , control group ; black circles and continuous line , intervention group control group patient variables all progressively deteriorated compared with their baseline performance ( esm table 1 ) . \n after intervention , the intervention group increased their habitual walking speed by 0.149 m / s ( 0.54 km / h ; p < 0.001 ) compared with the control group . \n in addition , a majority of secondary outcome variables showed significant between - group differences ( at the bonferroni corrected significance level of p < \n these outcome variables were : the dynamic balance test ( time to walk over a beam ) , the poma test ( total score and sub - scores ) , the biodex sway index recorded at level 6 , the fes - i score , the hip and ankle plantar flexor strength , and hip flexions mobility . \n after 6 months , the differences in all these variables remained significant ( p < 0.0026 ) except for the biodex sway index ( p = 0.005 ) and ankle plantar flexor strength ( p = 0.217 ) ( esm table 1 ) . \n this study aimed to evaluate the effect of a training programme , which was based on core components for successful fall prevention in the elderly , on gait and balance of diabetic patients . \n our results confirm that gait and balance in these patients can be concurrently improved by a targeted intervention . \n patients in the intervention group increased gait velocity , balance , muscle strength and joint mobility , and decreased their fear of falling . however , post intervention evaluation showed no difference between groups for the primary outcome cvgct ( esm table 1 ) . possibly the tarred surface was not challenging enough to fully reveal the gait problems of our diabetic patients . \n the cvgct was relatively low at baseline ( 2.75% for control group , 2.6% for intervention group ) and consequently did not improve ( decrease ) after treatment , probably due to a floor effect . \n step time variability on smooth and irregular surfaces was recently shown to be most strongly associated with reduction in step length on an irregular surface as compared with a smooth surface . \n richardson et al . have shown that the greater the decrease in step length on an irregular surface , the greater the step time variability on both surfaces , and the greater the increase in step time variability on the irregular surface . \n thus , analysis on a more challenging surface , e.g. cobblestone pathway , which was beyond this paper s aim , might have revealed differences between groups . despite the above , \n the degree of improvement achieved by the intervention group in gait velocity ( 0.54 km / h or 11.6% ) and dynamic balance ( time to walk over a beam ) ( 3.39 s or 34% ) was not only significant but also clinically relevant . \n a decrease in gait speed of 0.1 m / s in the elderly has been associated with a 10% decrease in the ability to perform daily living activities . \n these values are just within the critical range ( 19 to 24 points ) that implies a moderate risk of falling . \n intervention group patients passed this moderate risk of falling cut - off point after the training . \n in addition , their change of 2.0 points signifies a real improvement considering that effects greater than 0.8 ( with a group size of n = 30 ) reputedly represent a significant improvement unrelated to chance fluctuations . the more difficult biodex balance test ( level 6 ) also highlighted patients progress in postural control . \n importantly , all gait and balance variables ( except the biodex balance test ) remained significant at 6-month follow - up , although some treatment benefit was lost . increased hip and ankle strength as well as ankle mobility \n may explain the progress in gait velocity and both static and dynamic balance , although the improvement of ankle dorsal flexor strength and ankle dorsiflexion mobility just failed to be significant at the bonferroni corrected significance level . \n these two values further decreased at 6 months , possibly explaining the regression of gait and balance measures . \n knee flexion mobility showed normal baseline values , thereby explaining the absence of improvement after training . \n we decided not to calculate the post - treatment group effect on knee and hip extension mobility as none of the patients had a flexor contracture . \n regarding the fes - i , patients showed a relatively low level of concern about falling . \n perhaps this result reflects our study population s relatively good gait function and functional capacity . \n this could have been influenced by the inclusion and exclusion criteria used and must be considered in the clinical decision - making process . \n it may be hypothesised that patients with more severe diabetic peripheral neuropathy or with more impaired functional capacity would benefit less from training , due to the fact that , from a functional point of view , the detrimental effects of the disease are impossible to reverse or compensate . \n patients suffering from more severe peripheral neuropathy could benefit even more from a structured exercise regimen , as their condition provides more scope for improvement . moreover , even though balance and gait changes seen in diabetic patients are probably primarily due to neuropathy , there are other potential contributors . \n gait impairments are also observed in diabetic patients without clinically detectable neuropathy , raising the question of whether it would be worthwhile to test a similar , but more intensive programme on diabetic patients without neuropathy in order to prevent further aggravation of gait and balance . \n all exercises were taught by qualified physiotherapists and were function - orientated . to boost patient motivation and enable them to interact with other patients , \n for further discussion of the results , the effect of our primary outcome was compared with the results of a meta - analysis evaluating the effect of exercise on gait speed in the elderly . \n this meta - analysis reported a success rate of 57% for exercise training on habitual gait speed . \n the overall gait speed change reported was 0.01 m / s compared with our 0.15 m / s . \n however , the range of velocity change was large ( 0.2 to 0.34 m / s ) , which could be due to the various studies included and the evaluation of populations with diverse co - morbidities under varied conditions ( e.g. 6 m distance compared with a 6 min walk ) . \n the values of our population ( control group 2.6% , intervention group 2.75% ) are between those reported for elderly non - fallers ( 2.1% ; mean age 76 years ) and those for elderly fallers ( 3.8% ; mean age 82 years ) , which was somewhat better than expected . \n however , this may be explained by the fact that our population was about 15 years younger than participants in hausdorff s trial . despite the beneficial effect of our programme on gait speed and balance , its influence on fall frequency in diabetic patients \n although the cvgct did not improve , our results provide encouraging data , which justify further studies with larger sample sizes focusing on fall frequency itself , physical activity level and quality of life . \n our baseline evaluation contains no information about patients cardiac status , severity of retinopathy , visual acuity , disease duration , orthostatic hypotension , medications or other possible factors related to gait and balance impairments , and to treatment responsiveness . \n the fact that the control group was given no attention at all may represent a confounder for this study s results . the degree to which an improvement depends on personal attention from the therapists , vs the effect of the actual exercise regimen , needs to be considered . \n however , the positive result on all measured outcomes clearly points to a beneficial effect due to therapeutic exercise . \n muscle strength was measured with a hand - held dynamometer , which gives a more precise measurement than manual muscle testing . \n however , the reliability and accuracy of the measurement may be limited by the investigator s ability to hold the dynamometer stationary and by the fact that participants may overpower the testers . \n we tried to minimise this problem by ensuring that the same person always carried out the tests . \n nevertheless , the relatively low ratio between ankle plantar flexor and ankle dorsal flexor strength could indicate an underestimation of plantar flexor strength . \n in addition , not only sagittal but also frontal plane muscle strength ( i.e. hip abductors and adductors ) , which is involved in frontal plane stability during gait , should be evaluated . \n although our study showed positive results , clinicians should be aware of possible adverse events . \n two patients developed pain in their achilles tendon , obliging us to slow down the progression for \n to the best of our knowledge , this is one of the first randomised controlled trials to describe an effective physiotherapy training programme geared to concurrently improving the balance and gait of diabetic patients . \n future studies should examine the effect of exercise regimens on patient groups differentiated by neuropathy status ( patients without , with mild or with severe peripheral neuropathy , identified by a more complex instrument for peripheral neuropathy screening ) . \n in addition , outcomes such as functional capacity , the number of falls or physical activity level should be considered in order to draw meaningful conclusions about exercise efficacy among patients with diabetes , thereby facilitating medical and clinical decision - making . \n the appraisal of ( 1 ) advantages , difficulties and feasibility of treatment , and/or ( 2 ) prevention of gait and balance problems , as well as ( 3 ) the related fall risk in diabetic patients may be another interesting issue for further quantitative and qualitative studies . \n a specific gait and balance training programme based on a circuit approach and including gait and balance exercises combined with function - orientated strengthening can improve gait speed and balance , and increase both muscle strength and joint mobility of diabetic patients with a vibration perception threshold 4 . \n further studies with a larger sample size are needed to explore the influence of these improvements on the number of reported falls , patients physical activity levels and quality of life . \n ", "role": "user" }, { "content": "aims / hypothesisgait characteristics and balance are altered in diabetic patients . \n little is known about possible treatment strategies . \n this study evaluates the effect of a specific training programme on gait and balance of diabetic patients.methodsthis was a randomised controlled trial ( n = 71 ) with an intervention ( n = 35 ) and control group ( n = 36 ) . \n the intervention consisted of physiotherapeutic group training including gait and balance exercises with function - orientated strengthening ( twice weekly over 12 weeks ) . \n controls received no treatment . \n individuals were allocated to the groups in a central office . \n gait , balance , fear of falls , muscle strength and joint mobility were measured at baseline , after intervention and at 6-month follow-up.resultsthe trial is closed to recruitment and follow - up . \n after training , the intervention group increased habitual walking speed by 0.149 m / s ( p < \n 0.001 ) compared with the control group . \n patients in the intervention group also significantly improved their balance ( time to walk over a beam , balance index recorded on biodex balance system ) , their performance - oriented mobility , their degree of concern about falling , their hip and ankle plantar flexor strength , and their hip flexion mobility compared with the control group . \n after 6 months , all these variables remained significant except for the biodex sway index and ankle plantar flexor strength . \n two patients developed pain in their achilles tendon : the progression for two related exercises was slowed down.conclusions/interpretationspecific training can improve gait speed , balance , muscle strength and joint mobility in diabetic patients . \n further studies are needed to explore the influence of these improvements on the number of reported falls , patients physical activity levels and quality of life.trial registration : clinicaltrials.gov nct00637546funding : this work was supported by the swiss national foundation ( snf ) : pbskp-123446/1/electronic supplementary materialthe online version of this article ( doi:10.1007/s00125 - 009 - 1592 - 4 ) contains supplementary material , which is available to authorised users .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: lectins are carbohydrate - reactive ligands that occur commonly in nature [ 1 , 2 ] . \n these are proteins and glycoproteins with carbohydrate - specific ligand activity that are heat sensitive and dependant on divalent cations . \n lectins react with sugars in glycolipids , glycoproteins or oligosaccharides [ 13 ] , and agglutinate erythrocytes via cell surface glycoproteins and glycolipids [ 1 , 2 ] . agglutination by lectins in vitro can be specifically inhibited with complementary simple sugars or oligosaccharides [ 1 , 2 ] . \n lectin haemagglutinins have been described in various species in the family panuliridae ( lobsters ) . \n a haemagglutinin from the freshwater lobster pacifastacus leniusculus had high specific activity against trypsinized rabbit erythrocytes and was inhibited by sialoglycoproteins such as mucin , fetuin , and ovalbumin [ 46 ] . \n although glycolipids appear to be at low levels on the surface of rat erythrocytes , there is enhaced exposure of glycolipids after treatment with proteolytic enzymes . \n agglutination activity for many of these lectins is enhanced by proteolytic enzyme treatment , providing evidence that these lectins react preferentially with glycolipids rather than glycoproteins . \n there is also an example of a plant lectin that reacts more strongly with proteolytic enzyme - treated rat red cells ; the solanum tuberosum ( potato ) lectin . \n this lectin that reacts preferentially with rat erythrocytes is most efficiently inhibited by a small oligosaccharide , n n n n-tetra - n - acetylchitotetraose . \n this lectin is also a strong agglutinin for rat erythrocytes that have been treated with proteolytic enzymes [ 1 , 9 ] . \n when a suitable substrate is available , purification strategies based on affinity chromatography provide a convenient single - step purification . \n there have been a number of reports of isolation of invertebrate lectins by affinity chromatography with fixed erythrocytes as a substrate . \n ochoa and kristiansen reported a similar procedure , using of red cell stroma as an affinity adsorbent . \n more specific techniques have included the use sepharose - colominic acid affinity chromatography to purify a sialic acid - specific lectin ( lag1 ) . \n this report describes the characterisation of a lectin from panulirus cygnus with selective reactivity with human abo group a red cells and with rat red cells . \n the properties and sugar reactivity of lectin are similar to characterised antibacterial lectins and it hypothesised that in this animal , this lectin may contribute to antibacterial activity in the haemolymph . \n lobsters of the species panulirus cygnus ( george , 1962 ) were trapped in waters near perth , western australia . within 12 hours of capture , an 18-gauge needle was inserted into the haemocoel , and haemolymph withdrawn into a 50 ml syringe . \n the haemolymph was allowed to clot , the exudate collected and stored in 1 ml portions at 20c . \n human type a , b , and o erythrocytes collected into edta were obtained from the australian red cross blood transfusion service . \n erythrocytes from chicken , dog , cat , horse , sheep , rat , and guinea pig collected in edta by venipuncture or cardiac puncture of clinically normal animals were obtained from a diagnostic veterinary laboratory . \n erythrocytes were washed and made up as 2.5% ( v / v ) suspensions in 100 mmol / l phosphate - buffered saline ( pbs ) ph 7.2 , containing 100 mmol / l cacl2 , 20 mmol / l mgcl2 and 15 mmol / l bovine serum albumin . \n papain was obtained from csl ( parkville , victoria , australia ) and erythrocytes treated using standard procedures recommended by the manufacturer . \n briefly , erythrocytes were washed 3 times in pbs and 500 l of packed erythrocytes incubated for 15 min at 37c with 500 l of a 1% ( w / v ) papain solution in 200 mmol / l acetate buffer \n the papainised erythrocytes were diluted in 100 ml of pbs and used immediately for ha tests . \n serial 1 : 2 dilutions of lectin were made in 25 l of pbs and 25 l of a 0.5% erythrocyte suspension added to each dilution . after 30-minute incubation at room temperature ( 2025c ) , haemagglutination was observed and scored on a 1 + to 4 + scale : a 1 + reaction was scored when erythrocytes were in small clumps but all of the erythrocytes were involved . \n the titre was interpreted as the highest dilution which produced at least 1 + agglutination of the 25 l volume used in the test . \n arbutin , cellobiose , n - acetylgalactosamine , -methylgalactoside , n - acetylglucosamine , glucose , a - methylglucoside , lactose , maltose , mannose , -methyl - mannoside , melibiose , raffinose and sucrose , all in the d - configuration , and l - fucose were purchased from the sigma chemical company ( st . \n louis , usa ) were made up as 100 mmol / l solutions in pbs . \n inhibition of ha by sugars was determined in v - bottom 96-well plastic microtitre trays , by mixing 25 l of 1 : 2 serial dilutions of sugar with 5 rat erythrocyte - ha units of haemolymph or affinity - chromatography purified lectin in 25 l of pbs . \n after incubation at room temperature for 30 mins , 25 l of a 0.5% suspension of rat erythrocytes was added . \n the results reported were a mean of 3 determinations , for the concentration of the sugar at which complete inhibition of ha was observed . \n blood from 4 rats was pooled , washed , and made up as 5% suspension . \n five ml of this suspension were added to 3 ml of con a - sepharose ( pharmacia fine chemicals , uppsala , sweden ) and incubated for 2 hours at 4c on a rotating mixer . \n 20 ml of pbs were added to the suspension , which was centrifuged at 100 g for 5 min and the supernatant discarded . to lyse erythrocytes bound to the con a \n , 5 ml of a 1% solution of triton - x 100 ( bdh chemicals , poole , uk ) were added to the pellet and the suspension was shaken for 1 min . \n the triton - x was then removed by washing 5 times with 20 ml of pbs as described above . \n the rat erythrocyte membrane proteins were fixed to the con a - sepharose and the unreacted con a inactivated by incubation at room temperature for 15 min with 10 ml of 10% glutaraldehyde . \n the glutaraldehyde was then removed by washing 3 times with 20 ml of pbs as described above . \n this rat erythrocyte membrane- ( rem- ) sepharose immunosorbent was used to purify the panulirus cygnus lectin by affinity chromatography . \n two ml of the rem - sepharose were poured into a c 10/10 chromatography column ( pharmacia fine chemicals , uppsala , sweden ) and washed with 100 ml of pbs . for affinity chromatography 1 ml of panulirus cygnus haemolymph \n was passed through the column and the column then washed with 100 ml of pbs . in separate experiments , \n elution of lectin was attempted with a 100 mmol / l glycine buffer ph 3 , 500 mmol / l urea 125 mmol / l sucrose in pbs or 200 mmol / l solutions of the sugars , n - acetylglucosamine , b - methylglucoside , maltose , n - acetylgalactosamine , lactose , a - methylgalactoside or mannose , in pbs . \n one ml of each solution was applied to the column , incubated for 10 min at room temperature , the column was then eluted with 5 ml of the same solution at a flow rate of 10 ml per hour and 1 ml fractions collected . \n the eluted samples were dialysed overnight against 500 mmol / l urea : 125 mmol / l sucrose . \n portions of the dialysed fractions were diluted 1 : 10 for ha tests with rat erythrocytes , to dilute the urea - sucrose solution . \n recovery was determined by dividing the total ha activity applied to the column by the total ha recovered . \n fractions containing ha activity were pooled and stored at 4c in 125 mmol / l sucrose500 mmol / l urea or frozen at 70c and used as a source of purified lectin described in other experiments . a sepharose 4b \n ( pharmacia - lkb biotechnology , north ryde , nsw , australia ) column 50 cm in length and 2.5 cm in diameter with a flow rate of 8 ml / hour was used for gel filtration . \n one ml of fresh haemolymph was applied to the column and eluted with a buffer containing 100 mmol / l tris / hc1 ph 8 . \n fractions of 5 ml were collected , the ha titre with rat erythrocytes and a280 measured , and then equal volumes of 500 mmol / l urea : 125 mmol / l sucrose added to each fraction . the elution volume for molecular weight markers ( feline panleukopenia virus to determine the void volume ; \n human igm , 960 kilodaltons ; human igg , 150 kilodaltons ; and human serum albumin , 69 kilodaltons ) had been determined previously . \n molecular size was determined from a graph of v \n e versus log10 molecular size . \n agarose gel electrophoresis of haemolymph was carried out on a gelman ( ann arbor , michigan , usa ) immunoelectrophoresis apparatus with gels prepared on glass slides 5 8 cm using 1% agar in 100 mmol / l barbiturate buffer , ph 8 , with a gel thickness 1.5 mm . \n a row of wells 1.5 mm in diameter and 2 mm apart were punched in the gel 1.5 cm from the edge of the gel and the wells filled with haemolymph . \n gels were electrophoresed at 30 milliamps for 1.5 hours using an lkb ( pharmacia - lkb biotechnology , north ryde , nsw , australia ) immunoelectrophoresis apparatus . at the completion of the run \n , the gels were cut into eight 1 cm slices and the slices ground in 1 ml of pbs with a mortar and pestle , centrifuged at 1000 g for 5 min , and the a280 and ha titre of the supernatant determined . \n haemolymph and purified lectin were electrophoresed on native and reducing polyacrylamide gels on a bio - rad ( bio - rad laboratories , sydney , nsw , australia ) system using techniques recommended by the manufacturer . \n gels were stained with coomassie blue and the intensity of bands quantified by scanning with an lkb laser densitometer ( pharmacia - lkb biotechnology , north ryde , nsw , australia ) . \n the ha titre for fresh haemolymph and purified lectin were determined after heating at 37c or at 56c for 30 min . \n serial 1 : 2 dilutions of haemolymph or purified lectin were made in 25 ml of both pbs with 1 \n mmol / l ethylenediaminetetraacetic acid ( edta ) without divalent cations and pbs containing 100 mmol / l cacl2 , 20 mmol / l mgcl2 , and 15 mmol / l bovine serum albumin . \n an equal volume ( 25 ml ) of a 0.5% suspension of rat erythrocytes , prepared in pbs without divalent cations , was added to each well . \n after incubation at room temperature for 30 min , ha titres were determined as previously described . \n five ml of affinity column purified lectin in pbs with ca and mg ions were stored at 4c for 5 days , and 1 ml of the same preparation was stored in pbs with 125 mmol / l sucrose : 500 mmol / l urea for 5 days at 4c . \n the stored lectins were then centrifuged ( 2,000 g , 15 min ) and the precipitate that was recovered dissolved in 200 ml of a 500 mmol / l sucrose : 2 mol / l urea solution . \n a 25 ml sample of the redissolved precipitate was diluted 1 : 100 in pbs and the ha activity with rat erythrocytes determined . \n agglutinated rat erythrocytes to a titre 128 times greater than that for sheep or human erythrocytes ( table 1 ) . \n after treatment with papain , the titre with rat erythrocytes increased 32 folds ( table 1 ) . \n chicken erythrocytes when untreated did not react but were agglutinated by p. cygnus lectin after papain treatment ( table 1 ) . \n there was no significant change in the titres after papain treatment for sheep erythrocytes or human erythrocytes ( table 1 ) . \n it has been noted in studies of the rat erythrocyte - reactive solanum tuberosum ( potato ) lectin rat erythrocytes that there is little n - acetylgalactosamine associated with surface glycoproteins on rat red cells ( 12 ) and the lectin most likely reacts through n - acetylglucosamine in a -linkage displayed on a glycolipid . \n the lectin was adsorbed to fixed rat red cells bound to a sepharose support maxtrix . \n lectin was eluted by n - acetylgalactosamine with a 60% recovery , n - acetylglucosamine with a 115% recovery , glycine buffer ph 3 with a 115% recovery , and 125 mmol / l sucrose : 500 mmol / l urea with 115% recovery ( table 2 ) . \n no lectin detectable by ha with rat erythrocytes was eluted from the rem - sepharose column by 0.1 mol / l solutions of maltose , -methylgalactoside , lactose , or mannose . \n a single protein of 67 kilodaltons molecular size was detected by page of affinity - purified lectin . when purified lectin was stored in pbs at 4c for 5 days , a white precipitate developed and complete loss of ha \n , 000 g , 15 min ) and redissolved in 200 ml of a 500 mmol / l sucrose : 2 mol / l urea solution , only 10% of the original ha activity with rat erythrocytes was recovered . \n mmol / l sucrose : 500 mmol / l urea , and after storage at 4c for 5 days there was no loss of activity . \n the ha activity of purified lectin with rat erythrocytes was inhibited by 6.2 mmol / l n - acetylglucosamine , 12.5 mmol / l n - acetylgalactosamine , and 50 mmol / l -methylgalactoside but was not inhibited by 100 mmol / l solutions of mannose , arbutin , cellobiose , fucose , lactose , maltose , melibiose , raffinose , or sucrose ( table 3 ) . \n the profile of sugars that inhibited ha activity of haemolymph and affinity - purified lectin by sugars was identical ( table 3 ) . \n lectin activity was detected when pbs with ca and mg ions was used as a diluent , no activity was detected in pbs containing 1 mmol / l edta . \n when purified lectin was heated at 56c for 30 min , no ha activity with rat erythrocytes remained . \n when haemolymph was subject to agarose electrophoresis , the major haemolymph proteins migrated in a region of -electrophoretic mobility while the lectin , representing 5.8% of the total protein , was detected in a region of electrophoretic mobility . when haemolymph was subjected to gel filtration on sepharose 4b , the ha activity eluted as a single peak that comprised 4% of the total protein , with an estimated molecular size of 1.8 megadaltons . \n this activity was well separated from a peak in the elution profile that represented 96% of the total protein , composed of proteins ranging between 100 and 300 kilodaltons molecular size . \n this was in contrast to that single 67,000 da band that was detected by laser densitometer scanning of polyacrylamide gels following electrophoresis of affinity - purified lectin , suggesting that in haemolymph the lectin existed as a multimeric macromolecule . \n for the p cyguns anti - a lectin characterised in this study , a 67,000 da subunit was detected under reducing conditons , with 1,800,000 da multimer observed by gel filtration . \n the purified lectin also autoprecipitated in pbs at 4c , suggesting that there was spontaneous aggregation unless it was stored under chatropic conditions ; in this study with sucrose - urea . \n the haemagglutinating lectin in p. cygnus haemolymph was heat sensitive and required divalent cations for activity , properties commonly observed for invertebrate lectins . \n the properties of the p. cygnus anti - a lectin were similar to those of the hemagglutinin from pacifastacus leniusculus . \n both lectins have been found to have a high specific activity against erythrocytes treated with proteolytic enzymes . \n the purified pacifastacus leniusculus hemagglutinin was 420,000 da . , which dissociated to monomeric glycoprotein subunits [ 46 ] . \n in a second report , an n - acetylgalactosamine reactive 11 s macromolecular lectin from homarus americanus ( lag-2 ) was reported to have properties similar to the p. cygnus lectin in that it dissociated subunits of 55,000 da [ 13 , 14 ] . \n the procedure for preparation of an affinity substrate , with gluteraldehyde as a fixative , was similar to those of desai and allen who reported the use of formalinised erythrocytes and reitherman et al . who reported the use of erythrocyte stroma . \n it may be possible to identify a more specific substrate using techniques similar to those reported for the lag1 sialic acid - specific lectin or for the potato lectin as it has a similar activity profile . \n detection of lectins that react with n - acetyl - substituted sugars is common in invertebrate species . \n a human a rbc agglutinin from marine prawn penaeus indicus , with reactivity enhanced by trypsinisation and a specificity for acetylated aminosugars , was inhibited by salmonella lipopolysaccharide . \n a lectin from the pearl oyster , pinctada fucata ( martensii ) also has properties similar to the p. cygnus lectin described in this report ; a sugar specificity for n - acetylgalactosamine and a subunit structure with subunits of 20,000 da in aggregates of 440,000 da in haemolymph . \n yeaton listed 40 invertebrate species with lectins with known sugar specificity and 16 of these were reactive with acetylated aminosugars such as n - acetyl galactosamine . \n antibacterial activity has also been described for n - acetyl - d - glucosamine or n - acetyl - d - galactosamine specific lectins - tachylectin-2 and tachylectin 3 from the japanese horseshoe crab , tachypleus tridentatus [ 18 , 19 ] . \n the hemagglutinating activity of tachylectin 3 was strongly inhibited by s - type lpss from escherichia coli o111:b4 and other s - type lipopolysaccharides ( lpss ) from gram - negative bacteria but not by r - type lpss lacking o - antigens . \n the authors suggest that tachylectin-3 specifically recognizes gram - negative bacteria through the unique structural units of o - antigens . \n it is not known how many of these also display antibacterial activity that would be expected from their pattern of sugar specificity . \n antibacterial activity in panulirus cygnus haemolymph , reported as nonspecific and mainly associated with haemocytes , was investigated as an indicator of lobster immune - system status and health condition . \n lobsters that survived a simulated live - shipment procedure exhibited significantly lower antibacterial activity in haemolymph than did those found dead or weak after holding in a tank , leading to a conclusion that handling stress was associated with high activity levels in lobster haemolymph . \n lectin reactivity with gram - negative bacteria has been consistently reported for marine invertebrates [ 21 , 22 ] . \n there are many similarities between the p. cygnus anti - a lectin reported here blood group reactive lectins from other invertebrates that play a role in defence against pathogens . a semiquantitative assay of the anti - a lectin levels by haemagglutination is a convenient rapid test that can be used to measure changes in this haemolymph protein in response to environmental conditions and to investigate whether the reported antibacterial activity is mediated by this lectin .", "role": "user" }, { "content": "a lectin detected in haemolymph from the australian spiny lobster panulirus cygnus agglutinated human abo group a cells to a higher titre than group o or b. the lectin also agglutinated rat and sheep erythrocytes , with reactivity with rat erythrocytes strongly enhanced by treatment with the proteolytic enzyme papain , an observation consistent with reactivity via a glycolipid . \n the lectin , purified by affinity chromatography on fixed rat - erythrocyte stroma , was inhibited equally by n - acetylglucosamine and n - acetylgalactosamine . \n comparison of data from gel filtration of haemolymph ( behaving as a 1,800,000 da macromolecule ) , and polyacrylamide gel electrophoresis of purified lectin ( a single 67,000 da band ) , suggested that in haemolymph the lecin was a multimer . \n the purified anti - a lectin autoprecipitated unless the storage solution contained chaotropic inhibitors ( 125 mmol / l sucrose : 500 mmol / l urea ) . \n the properties of this anti - a lectin and other similar lectins are consistent with a role in innate immunity in these invertebrates .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: for the past 50 years , the pressurized metered - dose inhaler ( pmdi ) and the nebulizer have been the primary means of delivering inhaled drugs to patients with asthma and copd . \n these devices can be used effectively , but are inefficient and may be difficult or cumbersome to use . \n some of the limitations of these standard inhaler devices are accentuated in patients with copd , especially if they are elderly or have severe disease . \n standard pmdis at best deposit 10%15% of the delivered dose in the lungs and most of the inhaled dose is deposited in the oropharynx . to perform optimally , \n pmdis require coordination of actuation with inhalation as well as a slow inspiratory flow rate and breath - holding ( wolff and niven 1994 ) . \n poor coordination of pmdi actuation with inhalation has been shown to result in lower lung deposition of drug and reduced lung function response ( newman et al 2001 ) . \n the pmdi breathing maneuver requires education and repeated instruction , and can be problematic for older patients with copd . \n addition of a spacer or holding chamber can decrease oropharyngeal drug deposition and improve lung delivery , but makes the system less portable . \n handling of a pmdi can also be more difficult if the patient has arthritis of the hands . \n while jet nebulizers may be popular with some patients with copd , they are time - consuming , very inefficient , and require cleaning . \n for routine use of treatment for ambulatory patients , standard jet nebulizers are not portable and have not been proven to offer additional efficacy in asthma or copd patients ( dolovich et al 2005 ) . \n other issues that may be prominent in an elderly copd population are the confusion that arises with prescription of multiple inhalers with different instructions for use and also the expense of newer inhaled drug device combinations . \n events of the past decade have stimulated development of novel drug formulations and delivery devices that have improved the efficiency , ease of use , and environmental impact of inhaled drug therapy . because of deleterious effects of chlorofluorocarbon ( cfc ) propellants on the ozone layer , the montreal protocol was developed by the united nations in 1987 , banning substances that deplete the ozone layer ( leach 1995 ) . \n this ban phased out the use of cfcs by 1996 , although pharmaceutical companies had exemptions . \n further developed countries will follow in the next few years . while the contribution of cfc inhaler propellants has a minute environmental impact \n development of novel inhaler devices has focused on three areas : pmdis with hydrofluoroalkane ( hfa ) propellants , dry powder inhalers ( dpis ) , and liquid multidose spray devices that do not require propellants . \n hfa - pmdis generate aerosols that exit at lower velocity and may contain smaller particles . \n this may improve lung deposition , but these devices still require good coordination and slow inhalation . \n dpis require high inspiratory flow rates and may not work effectively in a patient with severe copd . \n dpis also are associated with high oropharyngeal deposition ( fink 2000 ) and the drug powder can be sensitive to moisture . respimat soft mist inhaler ( boehringer ingelheim , ingelheim , germany ) is a novel , multidose , propellant - free , hand - held liquid inhaler that represents a new category of inhaler devices . \n soft mist is used to describe the mechanism of aerosol generation and the qualities of the aerosol cloud . the aerosol plume generated by respimat travels \n much slower and lasts much longer than aerosol clouds from other devices , properties that improve delivery and make this device a valuable addition to inhalers available for inhalation therapy to copd patients . \n respimat is a hand - held inhaler with a hinged cap that is similar in size to pmdis and some dpis ( figure 1 ) . \n medication is stored as a solution in the drug cartridge , an aluminum cylinder containing a double - walled , plastic , collapsible bag that contracts as the solution is used . \n the solution may be formulated with either ethanol or water , with benzalkonium chloride and ethylene diamine tetra - acetic acid ( edta ) added as preservatives . \n the amount of preservatives in each puff is extremely low : approximately 0.44 g for benzalkonium chloride and 2.2 g for edta . \n tests on used cartridges have shown that patient use does not cause bacterial contamination of the solution in the cartridge . \n the first marketed product delivers 120 actuations and has a dose indicator , which is a color - coded gauge marked in increments of 30 doses . \n this indicator gives an estimate of doses remaining but does not count individual doses . after 120 actuations have been delivered , \n a locking mechanism prevents further use by preventing twisting of the base so that no further doses can be actuated . \n twisting the base of the device 180 degrees compresses a spring and provides mechanical power to aerosolize the dose of drug and also transfers a metered dose of drug ( usually 1015 l ) from the drug cartridge through a capillary tube to the pump cylinder . when the dose - release button is pushed , the energy from the compressed spring forces the drug through a nozzle system called the \n the uniblock consists of a silicone wafer bonded to a glass plate and measures approximately 2 x 2.5 mm . \n channels are etched into the silicon wafer using a technique derived from microchip technology and these channels feed into the nozzle outlet . \n actuation of the respimat dose - release button utilizes the mechanical energy from the spring to force the metered drug solution through the channels in the uniblock , producing two fine jets of liquid at the outlet that converge at a predetermined angle to form the aerosol cloud ( spallek et al 2002 ) . \n this cloud contains an aerosol with a fine - particle fraction ( particles smaller than 5.8 m ) at least twice as high as most pmdis and dpis , which would allow a higher proportion of the emitted dose to be delivered to the lungs and less to the oropharynx . \n the fine particle fraction is higher for ethanolic formulations than for aqueous formulations , with a mass median aerodynamic diameter of 2.00.4 m for aqueous solutions and 1.00.3 m for ethanolic solutions ( zierenberg 1999 ) . \n the fine - particle fraction is approximately 66% for an aqueous drug solution and 81% for an ethanolic solution . \n moves more slowly and has a more prolonged duration than the aerosol cloud from a pmdi . \n hochrainer et al ( 2005 ) have compared respimat aerosol velocity and spray duration with that of cfc - pmdis and hfa - pmdis via video - recording ( figure 3 ) . \n the velocity of the aerosol from respimat was between one - sixth and one - tenth of that from the cfc - pmdis and two of the hfa - pmdis and approximately one - third of the velocity of the slower hfa - pmdis . \n the mean velocity of the aerosol cloud measured at a 10 cm distance from the nozzle was 0.8 m / s for respimat and 2.08.4 m / s for pmdis , while the mean duration was 1.5 s and 0.150.36 s , respectively . \n the combination of smaller particle size , lower velocity , and longer duration of the aerosol cloud implies that there would be improved coordination of inhalation with actuation , higher lung deposition , and lower oropharyngeal deposition compared with pmdis . after receiving a new respimat inhaler , \n a patient must insert the cartridge by removing the transparent base and pushing the cartridge into the inhaler until it clicks into place . \n the dose is loaded by holding the inhaler in an upright position and turning the base 180 degrees until it clicks . \n the inhaler requires priming prior to first use by actuating until an aerosol cloud is visible and then completing three more actuations . \n spray content uniformity measurements show priming actuations necessary to achieve 100% of target volume and also show spray uniformity over 120 doses without tail - off effect ( spalleck 2002 ) . priming with actuation of one dose \n is recommended after a week of no use , and full priming is recommended after 21 days of no use . \n instructions for inhalation direct the patient to breathe out slowly and deeply and close lips around the end of the mouthpiece while holding the inhaler in a horizontal position . the dose - release button should be pushed while the patient takes a slow , deep breath in through their mouth and a 10-second breath - hold is recommended . \n the dose can be administered to the patient with the inhaler held in any position . \n improved lung deposition of drug aerosols from the respimat has been demonstrated by several studies using radiolabeled drug particles and gamma scintigraphy ( newman et al 1996 , 1998 ; steed et al 1997 ) . \n this group of studies in healthy nonsmoking volunteers used either fenoterol , which was formulated in an aqueous medium , or flunisolide , formulated in 96% ethanol . in one study with flunisolide , \n the mean whole - lung deposition from respimat ( 40% of the metered dose ) was significantly higher than from the pmdi ( 15% ) or pmdi plus spacer ( 28% ) ( newman et al 1996 ) . \n a follow - up study using flunisolide and a final prototype respimat showed significantly more lung deposition with respimat compared with pmdi plus spacer ( 45 vs 26% ) ( newman et al 1998 ) . in this same study , mean whole - lung deposition of fenoterol was significantly greater when delivered by respimat ( 39% ) than via pmdi ( 11% ) or pmdi plus spacer ( 10% ) . in both of these studies in normal subjects , \n the oropharyngeal deposition was significantly lower with respimat than with pmdi ( approximately 40% vs 70% ) , but not as low as with pmdi plus spacer . \n a more recent investigation has compared lung deposition of inhaled steroids in mild to moderate asthmatic subjects using respimat , turbuhaler , and a pmdi ( pitcairn et al 2005 ) . \n respimat contained budesonide solution , the turbuhaler contained budesonide dry powder , and the pmdi contained beclomethasone dipropionate ; the turbuhaler inhalations were performed at either 60 or 30l / m . \n mean whole - lung deposition of drug from respimat was significantly greater than that from turbuhaler dpi at fast or slow inhaled flow rates , or from the pmdi . \n the deposition pattern within the lungs was more peripheral for the respimat than for the turbuhaler . \n these data in normal and asthmatic subjects would predict that lower doses of drugs via the respimat would provide equal efficacy to higher doses delivered via the pmdi or turbuhaler . \n currently , the respimat is marketed with a combination of ipratropium bromide ( ib ) and fenoterol hydrobromide ( fen ) ( berodual respimat ) and was launched in germany in january 2004 . \n five clinical studies have been performed with berodual respimat in patients with copd and in adults and children with asthma ( reviewed in kssner et al 2004 ) . \n a pivotal phase iii , multicenter , parallel - group study of 892 patients with moderate to severe copd compared ib / fen via respimat with a cfc - pmdi ( kilfeather et al 2004 ) . \n patients were randomized to one of five treatment arms : respimat containing ib 10 g / fen 25 g , respimat containing ib 20 g / fen50 g , pmdi containing ib 20 g/ fen50 g , respimat placebo , or pmdi placebo four times daily for 12 weeks . \n the primary efficacy endpoint was the average change from pre - dose in fev1 over the first hour after dose administration on day 85 of treatment and the study was powered for non - inferiority . \n the bronchodilator response to ib / fen on day 85 showed that the 20/50 g dose via respimat was not inferior to the 40/100 g dose via cfc - pmdi ( figure 5 ) . \n four trials of ib / fen via respimat have been conducted in patients with asthma ( thee in adults and on in children ) . \n two of these were proof - of - concept , phase ii , dose - ranging and cumulative dose studies in adults with asthma ( kunkel et al 2000 ; goldberg et al 2001 ) . in the dose - ranging study ( \n goldberg et al 2001 ) , five different doses of ib / fen ( from 5/12.5 g to 80/200 g ) were used and showed a log - linear dose response for average increase in fev1 up to 6 hours . \n responses to ib / fen doses of 5/12.5 and 10/25 g administered via respimat were closest or slightly superior to that for the ib / fen dose of 40/100 g delivered with cfc - pmdi . \n therapeutic equivalence could not be demonstrated statistically in this study due to higher - than - expected variability . \n the cumulative dose study in adults with asthma ( kunkel et al 2000 ) concluded that ib / fen delivered by respimat was as effective as the cfc - pmdi at half the cumulative dose . \n two phase iii studies were done comparing ib / fen via respimat and cfc - pmdi in adults and children with asthma ( vincken et al 2004 ; von berg et al 2004 ) . \n these studies concluded that delivery by respimat instead of a cfc - pmdi allows a two- to four - fold reduction in dosage of ib / fen while achieving similar efficacy . \n these trials in copd and asthmatic subjects provide evidence in favor of the deposition experiment predictions that ib / fen delivered by respimat can be given at a reduced dosage ( one - fourth to one - half ) compared with that given by cfc - pmdi without any loss of efficacy . \n the only other clinical trial published to date using respimat in copd patients was a cumulative dose study of ipratropium bromide compared with delivery via pmdi ( iacono et al 2000 ) . \n this was a three - period cross - over study in 36 patients in which two dosages of ib by respimat were used ( 10 and 20 g per puff ) compared with 20 g per puff via cfc - pmdi . \n the study found greater bronchodilation from half the cumulative dose of ib by respimat compared with the pmdi . \n there have been two phase ii published comparative trials using fen , given alone to asthmatic subjects via respimat and cfc - pmdi ( van noord et al 2000 ; vincken et al 2003 ) , and again showing the ability to use reduced doses with the respimat . \n there have also been clinical trials conducted examining clinical efficacy and safety of tiotropium bromide delivered by respimat in copd subjects , but these have not been published . \n safety analysis of the five clinical trials using ib/ fen in the respimat showed an adverse event profile similar to the cfc - pmdi . in one of the phase \n ii studies ( kunkel et al 2000 ) , the 320/800 g dose given with respimat was associated with a slightly higher incidence of headache , nervousness , and tremor than the same dose by pmdi . \n this may have been due to slightly increased 2-adrenergic stimulation and cholinergic blockade with the greater drug delivery to the lungs by the respimat . in the phase iii studies , the adverse - event profiles of the 10/25 and 20/50 g doses of ib / fen via respimat were comparable with that of the 40/100 g dose via cfc - pmdi , and the frequency of adverse events thought to be treatment - related was low across all groups . \n because of the use of the preservatives benzalkonium chloride and edta in bronchodilator preparations in the respimat , there have been questions about the possibility of paradoxical bronchoconstriction with respimat . \n this has been analyzed in both the phase ii and phase iii data sets for ib / fen and either drug alone , and incidence of paradoxical bronchoconstriction was not found to be increased compared with cfc - pmdi ( koehler et al 2004 ; hodder et al 2005 ) . \n for the copd and asthma patients in this analysis , there were no observed episodes of bronchospasm following administration of active drug or placebo via the respimat . \n the incidence of asymptomatic falls in fev1 > 15% from baseline after respimat use was 0%2.8% in the active treatment group and 0%7.6% in the placebo group and was no different than that measured after cfc p - mdi . \n many patients lack coordination for the split - second timing required between beginning a slow inhalation and activation of a pmdi ( mcfadden 1995 ; fink and rubin 2005 ) . \n asynchronous actuation can greatly reduce the amount of medication inhaled from a pmdi ( wilkes et al 2001 ) and can also reduce clinical effect of the inhaled drug ( mcfadden 1995 ; newman et al 2001 ) . \n one study showed that incidence of critical errors in pmdi use were significantly higher in copd patients ( 26% ) compared with asthma patients ( 13% ) ( melani et al 2004 ) . \n breath coordination can be addressed by use of breath - actuated pmdis , pmdis plus spacer devices , dpis , or nebulizers ( newman 2005 ) . \n newer hfa - pmdis create aerosols that exit at a lower velocity than cfc - pmdis and may have a smaller particle size , both factors which may help overcome problems with poor coordination . like the pmdi , respimat is also a press and breathe device and requires some coordination of actuation and inhalation . \n respimat demonstrates lower aerosol velocity and longer spray duration that either cfc or hfa pmdis , which should allow patients to coordinate actuation and breathing more easily . \n the deposition data show that respimat deposits significantly more drug in the lungs of asthmatic patients than the turbuhaler dpi or a cfc - pmdi in the setting of optimal inhalation technique . to date , no studies have been published that examine drug deposition from the respimat in subjects with copd or assess deposition and efficacy of respimat in patients with poor inhalation technique . in a clinical trial comparing ib \n / fen via respimat or an hfa - pmdi in 245 patients with copd , asthma or mixed disease , correct assembly , and inhaler technique were assessed after training at the beginning of each treatment period ( schurmann et al 2005 ) . \n patients were given up to five attempts to demonstrate satisfactory technique and were scored on seven different device handling and breathing tasks . at the beginning of each treatment period , 96.4% could demonstrate satisfactory inhaler technique with respimat by the final attempt , compared with 98% of patients with hfa - pmdi . \n the proportion of patients achieving a score of 7 at the first attempt was higher for hfa - pmdi ( 80% ) than for respimat ( 48% ) , perhaps due to the novelty of the respimat device . \n while patients required more training for good technique with respimat , patients retained good technique with respimat after 7 weeks ( 97% ) , compared with 94% in th hfa - pmdi group . \n most patients found the respimat easy to assemble and only one patient was unable to assemble the device . \n with the multitude of inhaler devices now available , there has been increased interest in the assessment of patient preference and satisfaction , as preference for a particular medication or inhaler device may be associated with improved adherence with therapeutic regimens . \n boehringer ingelheim developed and validated a patient satisfaction and preference questionnaire for inhalation devices to better assess satisfaction with the respimat compared with other devices ( kozma et al 2005 ) . \n the patient satisfaction and preference questionnaire ( pasapq ) was developed using published papers , focus groups , and expert opinion . \n the final questionnaire contains 14 satisfaction items , including a global satisfaction question , as well as one preference question and one question on willingness to use the device in the future . \n the satisfaction items were grouped into two domains : performance ( seven items ) and convenience ( six items ) . of all device satisfaction instruments that have been used in clinical trials , only the pasapq has a published validation and determination of minimally important difference , which is very important for discriminating the degree of difference that is clinically significant . \n the pasapq was used in a study specifically designed to examine preference for and satisfaction with inhaler devices in patients with copd , asthma , or mixed disease in a crossover study of ib / fen delivered via respimat vs hfa - pmdi ( schrmann 2005 ) . \n the questionnaire was administered after each 7-week treatment period and of the 201 out of 224 subjects expressing a preference , 81% preferred respimat . \n of the 44 patients who had concomitant diagnoses that might affect inhaler handling , such as eye problems or arthritis , 89% preferred respimat . \n patients were more willing to continue to use respimat and mean ratings for 13 of 15 items in the satisfaction questionnaire were significantly higher for respimat . \n there were no differences between the inhalers for efficacy measures such as peak expiratory flow , rescue inhaler use , and symptom scores . \n taking device preference and satisfaction into account when choosing an inhaler device may be associated with improved clinical outcomes , but this has not been proven to date . \n respimat represents a novel approach to the delivery of inhaled drugs and overcomes some of the limitations of pmdis , dpis , and nebulizers . \n it is portable , propellant - free , uses mechanical energy for actuation , and does not require cumbersome spacers or holding chambers . unlike some dpis , optimal aerosol generation does not depend on high inspiratory flow rates . \n respimat produces an aerosol with a greater fine - particle fraction than most pmdis , dpis , and nebulizers and the aerosol spray produced exits the inhaler more slowly and lasts for a longer time . \n this translates into higher lung drug deposition and lower oropharyngeal deposition than the pmdi and also turbuhaler dpi . \n for some drug formulations , therapeutic ratio could be improved with respimat , by offering higher lung deposition with lower oropharyngeal deposition and lower nominal dosing . \n it is also possible that drug delivery and efficacy will be improved with respimat in those patients who have difficulties in actuating and coordinating inhalation when using a pmdi , but the device still requires some degree of hand breath synchronization . in clinical trials in patients with copd , \n bronchodilator drugs delivered from respimat were equally effective at half of the dose delivered from a pmdi . in one study of inhaler preference , \n respimat was preferred over the pmdi by patients with copd and other obstructive lung diseases . \n it is not clear , however , if preference for the device will lead to improved adherence and clinical outcomes . \n currently , respimat is available in germany containing a combination of ipratropium bromide and fenoterol . as availability increases , \n respimat is a novel and valuable addition to the range of inhaler devices available to the patient with copd . \n breath coordination that may be a problem for patients when using a pmdi and does not require generation of high inspiratory flow rates required for some dpis . \n respimat also makes it possible to give lower nominal doses of delivered drugs without decreasing efficacy . a continuing challenge in this population of patients , however , is the expense and confusion engendered by use of multiple inhaler devices .", "role": "user" }, { "content": "events of the past decade have stimulated development of new drug formulations and delivery devices that have improved the efficiency , ease of use , and environmental impact of inhaled drug therapy . \n respimat soft mist inhaler is a novel , multidose , propellant - free , hand - held , liquid inhaler that represents a new category of inhaler devices . \n the aerosol cloud generated by respimat contains a higher fraction of fine particles than most pressurized metered dose inhalers ( pmdis ) and dry powder inhalers ( dpis ) , and the aerosol spray exits the inhaler more slowly and for a longer duration than with pmdis . \n this translates into higher lung drug deposition and lower oropharyngeal deposition , making it possible to give lower nominal doses of delivered drugs without lowering efficacy . in clinical trials in patients with copd , bronchodilator drugs delivered from respimat \n were equally effective at half of the dose delivered from a pmdi . \n in one study of inhaler preference , respimat was preferred over the pmdi by patients with copd and other obstructive lung diseases . \n respimat is a valuable addition to the range of inhaler devices available to the patient with copd .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: the functional assessment of cancer therapy - general ( fact - g ) questionnaire , designed to measure quality of life ( qol ) in cancer patients , has gone through many validation studies , both in its english and translated versions [ 2 - 5 ] . \n however , little research has been conducted in south american spanish speaking patients . a previous study performed among uruguayan cancer patients using fact - g spanish version 2 showed acceptable to good reliability and validity except for the emotional well - being subscale . \n cella and his colleagues also recognized this potential problem and subsequently revised the items in a new spanish version 3 and its most recent spanish version 4 in order to improve its reliability . \n major changes include adding one previously available but not scored item to the scoring algorithm ( \" i worry my condition will get worse \" \" me preocupa que mi enfermedad empeore \" ) , rephrasing some other items to improve readability and removing the 2-item relationship with doctor subscale . these remarks the need for additional validation studies for the spanish - speaking cancer patient population in south america . \n another reason for further psychometric studies on fact - g is that , up to date , its spanish version has been validated using classic test theory ( ctt ) approaches like other qol questionnaires . \n more recently , item response theory ( irt ) measurement models have entered the field and researchers are increasingly enthusiastic for the prospect of deriving better definitions of underlying constructs and the opportunity to turn attention away from static tests and scales to items and the incremental information they provide . the present study aimed to evaluate the performance of the fact - g spanish version 4 in uruguayan cancer patients using both classic psychometric and item response theory based approaches . \n the data were collected from cancer patients , between 18 and 75 years of age , with various tumor sites , at different stages of disease and under different forms of treatment . to be eligible patients must have been fluent in spanish . \n potential participants were identified from the daily record of office visits , treatment visits and inpatient hospitalizations . to ensure sufficient experience with treatment related side - effects \n , patients must have completed a minimum of two cycles of chemotherapy and/or 10 radiation therapy sessions or one month of hormone therapy \n . there must have been at least one month since last surgery . to ensure heterogeneity of the socioeconomic features , patients from one private ( centro de asistencia del sindicato mdico del uruguay casmu ) and three public ( hospital de clnicas de la universidad de la repblica , \n instituto de oncologa del msp , servicio de oncologa radioterpica del hospital pereira rossell ) hospitals of the city of montevideo were recruited for the study . \n two physician rated qol questionnaires , the ecog performance status rating and the spitzer 's quality of life - index doctor version ( qli - d ) were completed either by the treating physician or oncologist . \n patient self - reported questionnaires included the functional assessment of cancer therapy - general ( fact - g ) spanish version 4 , the spitzer 's quality of life - index patient version ( qli - p ) , the profile of mood states , short form ( poms - sf ) and the marlowe - crowne social desirability scale ( mcsds ) . \n ecog performance status rating ( ecog psr ) is a five - point scale ranging from 0 ( fully ambulatory ) to 4 ( not being able to leave bed ) . \n the quality of life index ( ql - i ) is a five - item questionnaire where each one of them explores a dimension or domain of quality of life : health , activity , daily living , support and outlook . \n although it was originally developed as an observer rated scale ( qli - d ) , it can also be used as a patient rated scale ( qli - p ) . for the purpose of the study , \n the ql - i was translated into spanish following a forward and backward translation procedure , carried out by an english native speaking linguist and a native spanish - speaking english translator . \n the spanish versions of the two qli questionnaires are available from the authors upon request . \n the functional assessment of cancer therapy - general questionnaire ( fact - g ) spanish version 4 is a widely used qol instrument . \n it comprises 27 questions that assess four primary dimensions of qol : physical ( pwb ; 7 items ) , social and family ( sfwb ; 7 items ) , emotional ( ewb ; 6 items ) , and functional well - being ( fwb ; 7 items ) . \n it uses 5-point likert - type response categories ranging from 0 = ' not at all ' to 4 = ' very much ' . \n the total fact - g score is the summation of the 4 subscale scores and ranges from 0 to 108 . \n data from a previous study on the fact - g spanish version 2 conducted among uruguayan cancer patients suggested that its reliability was acceptable to good in all subscales except for the ewb scale . \n an important question raised by these results was whether these subscales showed sufficient internal consistency to justify their use across cultures and whether there was equivalence of the spanish ewb to its english counterpart . \n ever since , developers of the fact - g revised the questionnaire into its most recent version 4 . \n major changes were the inclusion of an additional item ( \" i worry my condition will get worse \" \" me preocupa que mi enfermedad empeore \" ) in the ewb subscale , the removal of the two - item \" relationship with the doctor \" subscale and the rewording of 12 spanish items to improve their readability . \n the profile of mood states , short form ( poms - sf ) is a widely used scale measuring subjective mood states , such as anxiety , tension , vigor , depression , fatigue and confusion . \n the poms - sf is a valid measure of affective states and psychological adjustment in cancer patients and is available in spanish . a total mood disturbance score ( poms tmd ) \n may be obtained by summing the five scores of tension , depression , anxiety , fatigue and confusion subscales and substracting vigor from these scores . \n only patients with a 6th grade or higher level of reading abilities were included in the analysis , according to the instrument developers ' instructions . the marlowe - crowne social desirability scale ( mcsds ) . \n the 10 items short form of the mcsds provides a measure of the degree to which participants endorse socially desirable characteristics . a validated spanish version of the questionnaire was completed by the study participants . \n demographic , disease and treatment information was collected from patients , the treating physician and verified by the research assistants with the participants ' medical record . \n classical psychometric approach for analysis of the data consisted of an examination of the reliability and validity of the fact - g version 4 . \n reliability was examined by internal consistency ( cronbach 's coefficient alpha ) for each subscale and the overall scale . \n construct validity was assessed by comparing mean differences in fact - g total and subscale scores according to known groups , i.e. patients performance status , in vs. out - patients and by studying the correlations between the instruments ( convergent and discriminant validity ) . \n anchor - based methods examine the relationship between scores on the instrument whose interpretation is under question ( target instrument ) and some independent measure ( an anchor ) . \n this approach requires that 1 ) the anchor is easily interpretable and 2 ) there must be appreciable association between the target and the anchor . \n differences in scores in relation to the clinical anchors can be then used to set the minimum important difference or clinically meaningful change in order to evaluate outcomes in clinical trials . \n anchor - based clinical significance was studied in order to determine clinically significant differences in qol assessments as measured by fact - g total and subscale scores , using tumor stage as a definite clinical criterion commonly used in the oncology field . \n differences of 5 to 10 score points in a 100 point scale are considered relevant in determining the clinical significance of qol measures . to examine the statistical magnitude of the observed differences , each mean \n difference score was standardized by relating this score to its standard deviation ( effect size ) . \n an effect size of d = 0.2 was taken to indicate a small difference , d = 0.5 a moderate difference , and d = 0.8 , a large one . \n the item response data were analyzed using andrich 's [ 19 - 22 ] rating scale model ( rsm ) . \n the rsm is an item response theory ( irt)-based measurement model and has been implemented in the winsteps computer program . \n the rsm specifies two facets ( person latent trait , bn ; item location , di ) , and the step threshold ( fi ) . \n the probability of person n responding in response category j to item i can then be expressed by the formula : ln [ pnij / pni(j-1 ) ] = bn - di - fj , in which pnij is the probability of person n endorsing or choosing in category j of item i , pni(j-1 ) is the probability of person n endorsing or choosing in category j - 1 of item i , bn is the latent trait measure ( e.g. , fatigue ) of person n , and \n di is the location of item i , and fj is the step threshold between categories j - 1 and j. in the present study , for example , f1 is the transition from intensity category 1 ( \" not at all \" ) to category 2 ( \" a little bit \" ) and f4 is the transition from category 4 ( \" quite a bit \" ) to category 5 ( \" very much \" ) . that is the point on the latent trait scale ( i.e. , pwb ) at which two consecutive category response curves intersect . \n in order to examine the fit of each item to measure a unidimensional construct ( e.g. , pwb ) , the infit and outfit mean square ( mnsq ) item fit statistics provided in the winsteps program were evaluated . \n item misfit indicates that an item is not measuring the same underlying construct as other items within the same scale . \n the infit mnsq is an information - weighted fit statistic , which is more sensitive to unexpected behavior affecting responses to items near the person 's trait level . \n the weighting reduces the influence of less informative , low variance , off - target responses . \n the outfit mnsq is an outlier - sensitive fit statistic , more sensitive to unexpected behavior by persons on items far from the person 's trait level . \n these statistics have an expected value of 1.0 , and range from 0 to infinity . \n values substantially below 1 indicate local dependencies in the data ; values substantially above 1 indicate noise . \n these values are on a ratio scale , so that 1.2 indicates 20% excess noise . \n we set .601.4 for infit mnsq and outfit mnsq as cut - off criteria for items with good fit . \n the data were collected from cancer patients , between 18 and 75 years of age , with various tumor sites , at different stages of disease and under different forms of treatment . to be eligible patients must have been fluent in spanish . \n potential participants were identified from the daily record of office visits , treatment visits and inpatient hospitalizations . to ensure sufficient experience with treatment related side - effects \n , patients must have completed a minimum of two cycles of chemotherapy and/or 10 radiation therapy sessions or one month of hormone therapy \n . there must have been at least one month since last surgery . to ensure heterogeneity of the socioeconomic features , patients from one private ( centro de asistencia del sindicato mdico del uruguay casmu ) and three public ( hospital de clnicas de la universidad de la repblica , \n instituto de oncologa del msp , servicio de oncologa radioterpica del hospital pereira rossell ) hospitals of the city of montevideo were recruited for the study . \n two physician rated qol questionnaires , the ecog performance status rating and the spitzer 's quality of life - index doctor version ( qli - d ) were completed either by the treating physician or oncologist . \n patient self - reported questionnaires included the functional assessment of cancer therapy - general ( fact - g ) spanish version 4 , the spitzer 's quality of life - index patient version ( qli - p ) , the profile of mood states , short form ( poms - sf ) and the marlowe - crowne social desirability scale ( mcsds ) . \n ecog performance status rating ( ecog psr ) is a five - point scale ranging from 0 ( fully ambulatory ) to 4 ( not being able to leave bed ) . \n the quality of life index ( ql - i ) is a five - item questionnaire where each one of them explores a dimension or domain of quality of life : health , activity , daily living , support and outlook . \n although it was originally developed as an observer rated scale ( qli - d ) , it can also be used as a patient rated scale ( qli - p ) . for the purpose of the study , \n the ql - i was translated into spanish following a forward and backward translation procedure , carried out by an english native speaking linguist and a native spanish - speaking english translator . \n the spanish versions of the two qli questionnaires are available from the authors upon request . \n the functional assessment of cancer therapy - general questionnaire ( fact - g ) spanish version 4 is a widely used qol instrument . \n it comprises 27 questions that assess four primary dimensions of qol : physical ( pwb ; 7 items ) , social and family ( sfwb ; 7 items ) , emotional ( ewb ; 6 items ) , and functional well - being ( fwb ; 7 items ) . \n it uses 5-point likert - type response categories ranging from 0 = ' not at all ' to 4 = ' very much ' . \n the total fact - g score is the summation of the 4 subscale scores and ranges from 0 to 108 . \n data from a previous study on the fact - g spanish version 2 conducted among uruguayan cancer patients suggested that its reliability was acceptable to good in all subscales except for the ewb scale . \n an important question raised by these results was whether these subscales showed sufficient internal consistency to justify their use across cultures and whether there was equivalence of the spanish ewb to its english counterpart . \n ever since , developers of the fact - g revised the questionnaire into its most recent version 4 . \n major changes were the inclusion of an additional item ( \" i worry my condition will get worse \" \" me preocupa que mi enfermedad empeore \" ) in the ewb subscale , the removal of the two - item \" relationship with the doctor \" subscale and the rewording of 12 spanish items to improve their readability . \n the profile of mood states , short form ( poms - sf ) is a widely used scale measuring subjective mood states , such as anxiety , tension , vigor , depression , fatigue and confusion . \n the poms - sf is a valid measure of affective states and psychological adjustment in cancer patients and is available in spanish . a total mood disturbance score ( poms tmd ) \n may be obtained by summing the five scores of tension , depression , anxiety , fatigue and confusion subscales and substracting vigor from these scores . \n only patients with a 6th grade or higher level of reading abilities were included in the analysis , according to the instrument developers ' instructions . the marlowe - crowne social desirability scale ( mcsds ) . \n the 10 items short form of the mcsds provides a measure of the degree to which participants endorse socially desirable characteristics . a validated spanish version of the questionnaire was completed by the study participants . \n demographic , disease and treatment information was collected from patients , the treating physician and verified by the research assistants with the participants ' medical record . \n classical psychometric approach for analysis of the data consisted of an examination of the reliability and validity of the fact - g version 4 . \n reliability was examined by internal consistency ( cronbach 's coefficient alpha ) for each subscale and the overall scale . \n construct validity was assessed by comparing mean differences in fact - g total and subscale scores according to known groups , i.e. patients performance status , in vs. out - patients and by studying the correlations between the instruments ( convergent and discriminant validity ) . \n anchor - based methods examine the relationship between scores on the instrument whose interpretation is under question ( target instrument ) and some independent measure ( an anchor ) . \n this approach requires that 1 ) the anchor is easily interpretable and 2 ) there must be appreciable association between the target and the anchor . \n differences in scores in relation to the clinical anchors can be then used to set the minimum important difference or clinically meaningful change in order to evaluate outcomes in clinical trials . \n anchor - based clinical significance was studied in order to determine clinically significant differences in qol assessments as measured by fact - g total and subscale scores , using tumor stage as a definite clinical criterion commonly used in the oncology field . \n differences of 5 to 10 score points in a 100 point scale are considered relevant in determining the clinical significance of qol measures . to examine the statistical magnitude of the observed differences , each mean \n difference score was standardized by relating this score to its standard deviation ( effect size ) . \n an effect size of d = 0.2 was taken to indicate a small difference , d = 0.5 a moderate difference , and d = 0.8 , a large one . \n the item response data were analyzed using andrich 's [ 19 - 22 ] rating scale model ( rsm ) . \n the rsm is an item response theory ( irt)-based measurement model and has been implemented in the winsteps computer program . \n the rsm specifies two facets ( person latent trait , bn ; item location , di ) , and the step threshold ( fi ) . \n the probability of person n responding in response category j to item i can then be expressed by the formula : ln [ pnij / pni(j-1 ) ] = bn - di - fj , in which pnij is the probability of person n endorsing or choosing in category j of item i , pni(j-1 ) is the probability of person n endorsing or choosing in category j - 1 of item i , bn is the latent trait measure ( e.g. , fatigue ) of person n , and di is the location of item i , and fj is the step threshold between categories j - 1 and j. in the present study , for example , f1 is the transition from intensity category 1 ( \" not at all \" ) to category 2 ( \" a little bit \" ) and f4 is the transition from category 4 ( \" quite a bit \" ) to category 5 ( \" very much \" ) . that is the point on the latent trait scale ( \n i.e. , pwb ) at which two consecutive category response curves intersect . in order to examine the fit of each item to measure a unidimensional construct ( e.g. , pwb ) , the infit and outfit mean square ( mnsq ) item fit statistics provided in the winsteps program were evaluated . \n item misfit indicates that an item is not measuring the same underlying construct as other items within the same scale . \n the infit mnsq is an information - weighted fit statistic , which is more sensitive to unexpected behavior affecting responses to items near the person 's trait level . \n the weighting reduces the influence of less informative , low variance , off - target responses . \n the outfit mnsq is an outlier - sensitive fit statistic , more sensitive to unexpected behavior by persons on items far from the person 's trait level . \n these statistics have an expected value of 1.0 , and range from 0 to infinity . \n values substantially below 1 indicate local dependencies in the data ; values substantially above 1 indicate noise . \n these values are on a ratio scale , so that 1.2 indicates 20% excess noise . \n we set .601.4 for infit mnsq and outfit mnsq as cut - off criteria for items with good fit . \n the item response data were analyzed using andrich 's [ 19 - 22 ] rating scale model ( rsm ) . \n the rsm is an item response theory ( irt)-based measurement model and has been implemented in the winsteps computer program . \n the rsm specifies two facets ( person latent trait , bn ; item location , di ) , and the step threshold ( fi ) . \n the probability of person n responding in response category j to item i can then be expressed by the formula : ln [ pnij / pni(j-1 ) ] = bn - di - fj , in which pnij is the probability of person n endorsing or choosing in category j of item i , pni(j-1 ) is the probability of person n endorsing or choosing in category j - 1 of item i , bn is the latent trait measure ( e.g. , fatigue ) of person n , and di is the location of item i , and fj is the step threshold between categories j - 1 and j. in the present study , for example , f1 is the transition from intensity category 1 ( \" not at all \" ) to category 2 ( \" a little bit \" ) and f4 is the transition from category 4 ( \" quite a bit \" ) to category 5 ( \" very much \" ) . that is the point on the latent trait scale ( \n in order to examine the fit of each item to measure a unidimensional construct ( e.g. , pwb ) , the infit and outfit mean square ( mnsq ) item fit statistics provided in the winsteps program were evaluated . \n item misfit indicates that an item is not measuring the same underlying construct as other items within the same scale . \n the infit mnsq is an information - weighted fit statistic , which is more sensitive to unexpected behavior affecting responses to items near the person 's trait level . \n the weighting reduces the influence of less informative , low variance , off - target responses . \n the outfit mnsq is an outlier - sensitive fit statistic , more sensitive to unexpected behavior by persons on items far from the person 's trait level . \n these statistics have an expected value of 1.0 , and range from 0 to infinity . \n values substantially below 1 indicate local dependencies in the data ; values substantially above 1 indicate noise . \n these values are on a ratio scale , so that 1.2 indicates 20% excess noise . \n we set .601.4 for infit mnsq and outfit mnsq as cut - off criteria for items with good fit . \n a total of 361 patients were approached and asked to participate . among them , 36 patients ( 10% ) either refused to participate , were too sick to complete the battery of questionnaires or a family member prevented the patient from participating . \n data collection for 16 other participants ( 4% ) was not completed due to other reasons . \n there were no significant differences between participants and non - participants with regard to age , gender , institution or tumor stage , however more non - participants were in - patients ( chi - square = 13.5 , p = .001 ) and rated higher in the ecog psr ratings ( chi - square = 7.0 , p = .03 ) . \n certain facts to be highlighted are that this is a sample of severely ill patients with 78% of them having regional and metastatic diseases ; only 13.9% of patients being fully employed , 27% reached less then the sixth year of formal education and with a very unequal income distribution . \n the distribution of income shows a very wide range in monthly income with an interquartile range of 192 and 571 dollars / month that highlights the kind of low income and unequal distribution that prevails in south american countries . \n as many as 41.7% of patients in the study sample stated not to have any religion , a typical characteristic of uruguayan culture , quite dissimilar to other south american countries . \n socio - demographic and clinical features of the sample ( n = 309 ) mean time since cancer diagnosis was 29 months ( sd = 39.5 months ; ranged 2 weeks to 24.5 years ) . as for treatment characteristics , \n 172 patients had undergone surgery ( 55.7% ) ; 204 received only one treatment modality , 95 of them were treated with chemotherapy ( cht ) ( 30.7% ) , 98 with radiotherapy ( rt ) ( 31.7% ) and 11 with hormone therapy ( ht ) ( 3.6% ) , while 100 patients received a combination of cht and rt ; 4 ( 1.3% ) were treated with rt and ht and 1 ( 0.3% ) with cht and ht . \n the timing of testing in relation to treatment varied along the sample . in 119 cases ( 38.5% ) \n , patients were interviewed during the week following their last treatment ( cht cycle or rt session ) ; in 64 cases ( 20.7% ) there had been between one week and one month since the last treatment ; in 44 cases ( 14.2% ) between 3 months and a year and 82 ( 26.5% ) had been off treatment for more than one year . \n the mode of administration of the fact - g ( self - administration vs. read in interview ) was registered in 303 cases . \n although the fact - g is designed for self - administration , most patients in our sample ( n = 205 , 67.7% ) requested some help from the interviewer to fill out the questionnaire . \n figures 1,2,3,4 show differences in sociodemographic and somatic features of the two groups of patients . \n t - test of independent samples showed that those patients capable of self administration were younger ( p < .000 ) while chi - square statistics showed that this group of patients had a higher education level ( p < .000 ) and better performance status ( lower ratings in ecog scale ) ( p < .000 ) . \n differences in mode of administration with age differences in mode of administration with gender differences in mode of administration with education differences in mode of administration with ecog - psr the reliability of the each of the fact - g scales was evaluated with cronbach 's coefficient alpha . \n the alpha coefficients for the total scale and the four fact subscales ( pwb , sfwb , ewb , fwb ) were quite good ( ranged .78 .91 ; see table 2 ) . \n table 2 also shows alpha coefficients of fact - g english and spanish version 2 . \n no relevant differences were found in cronbach alpha coefficients for total fact - g and its subscales when the group of patients who filled out the questionnaires by self administration ( cronbach 's alpha = .78 .91 ) and by interview ( cronbach 's alpha = .79 .89 ) were studied separately . \n internal consistency of fact - g and subscales pwb = physical well - being ; fwb = functional well - being ; sfwb = social and family well - being ; ewb = emotional well - being ( * ) includes \" satisfaction with sexual life \" . \n scheff post - hoc comparisons showed significant differences in fact - g total and subscale scores according to ecog psr ( table 3 ) , indicating that patients with worse functional status rated lower in the qol multidimensional assessment . due to the small number \n , patients rated \" 3 \" or \" 4 \" on ecog psr were combined with individuals rated \" 2 \" . \n total fact - g scores and subscale scores , with the exception of the pwb subscale , also enabled to discriminate among groups according to patient location at the moment of filling out the questionnaire ( out - patient vs. in - patient ) , see table 3 . \n differences in fact - g scores according to criteria groups * scheff comparisons ; the symbol > separates groups with scores significantly higher than those with lower scores . * \n significant p < 0.01 as another evidence of validity , tumor stage ( local vs. regional vs. metastatic disease ) was examined as a clinical anchor and differences in mean scores and effect sizes were calculated ( table 4 ) . \n differences of approximately 5 to 10 % points in total fact - g score ( 5.6 to 10.5 points in a 108 point scale ) were observed between local vs. metastatic and regional vs. metastatic diseases . \n accordingly differences of 11 to 18% points in the pwb subscale score ( 3 to 5 points in a 28 point subscale ) and of 9% in the fwb subscales ( 2.6 points in a 28 point subscale ) were observed between the ratings of patients with local and regional diseases vs. those with spread forms of cancer . \n differences in fact - g and subscale scores with tumor stage and effect size convergent and discriminant validity was evaluated using data from the whole set of patients with the exception of the poms - sf questionnaire . in this case , only patients that had completed the sixth grade of primary school and higher were included according to the poms manual 's instructions . as expected , pearson correlation coefficients were high between the fact - g total score and its subscale scores , ranging from r = .53 to r = .80 , see table 5 . similarly , moderate but statistically significant correlations ( \n r = .30 and higher ) were observed between ql - i total score in both doctor and patient versions as well as between ql - i items and the corresponding fact - g subscales ( ql - id and ql - ip activity , daily living and health and fwb ; ql - id and ql - ip support and sfw ) , ( table 5 ) . \n correlation between the fact - g and the poms - sf total mood disturbance score ( poms tmd ) is also relatively high . \n as expected , the correlation coefficients between the fact - g total and subscale scores and the mcsds-10 are low . \n correlation between fact - g , qli doctor and patient version , poms - sf , mcsds-10 * * correlation is significant at the 0.01 level . * \n . the results of rasch analyses confirmed the unidimensionality of each subscale of the fact - g with two exceptions ( see table 6 ) . \n gs7 ( i am satisfied with my sex life ) of the sfwb subscale had both mnsq fit statistics greater 1.40 , indicating it did not perform well with the other items in the same scale . \n ge2 ( i am satisfied with how i 'm coping with my illness ) of the ewb also had large mnsq fit statistics , indicating its poor fit to the unidimensionality model with the other items on the same scale . \n the reliability of the each of the fact - g scales was evaluated with cronbach 's coefficient alpha . \n the alpha coefficients for the total scale and the four fact subscales ( pwb , sfwb , ewb , fwb ) were quite good ( ranged .78 .91 ; see table 2 ) . \n table 2 also shows alpha coefficients of fact - g english and spanish version 2 . \n no relevant differences were found in cronbach alpha coefficients for total fact - g and its subscales when the group of patients who filled out the questionnaires by self administration ( cronbach 's alpha = .78 .91 ) and by interview ( cronbach 's alpha = .79 .89 ) were studied separately . \n internal consistency of fact - g and subscales pwb = physical well - being ; fwb = functional well - being ; sfwb = social and family well - being ; ewb = emotional well - being ( * ) includes \" satisfaction with sexual life \" . \n scheff post - hoc comparisons showed significant differences in fact - g total and subscale scores according to ecog psr ( table 3 ) , indicating that patients with worse functional status rated lower in the qol multidimensional assessment . due to the small number \n , patients rated \" 3 \" or \" 4 \" on ecog psr were combined with individuals rated \" 2 \" . \n total fact - g scores and subscale scores , with the exception of the pwb subscale , also enabled to discriminate among groups according to patient location at the moment of filling out the questionnaire ( out - patient vs. in - patient ) , see table 3 . \n differences in fact - g scores according to criteria groups * scheff comparisons ; the symbol > separates groups with scores significantly higher than those with lower scores . * \n significant p < 0.01 as another evidence of validity , tumor stage ( local vs. regional vs. metastatic disease ) was examined as a clinical anchor and differences in mean scores and effect sizes were calculated ( table 4 ) . \n differences of approximately 5 to 10 % points in total fact - g score ( 5.6 to 10.5 points in a 108 point scale ) were observed between local vs. metastatic and regional vs. metastatic diseases . \n accordingly differences of 11 to 18% points in the pwb subscale score ( 3 to 5 points in a 28 point subscale ) and of 9% in the fwb subscales ( 2.6 points in a 28 point subscale ) were observed between the ratings of patients with local and regional diseases vs. those with spread forms of cancer . \n differences in fact - g and subscale scores with tumor stage and effect size convergent and discriminant validity was evaluated using data from the whole set of patients with the exception of the poms - sf questionnaire . in this case , only patients that had completed the sixth grade of primary school and higher were included according to the poms manual 's instructions . \n as expected , pearson correlation coefficients were high between the fact - g total score and its subscale scores , ranging from r = .53 to r = .80 , see table 5 . similarly , moderate but statistically significant correlations ( r = .30 and higher ) were observed between ql - i total score in both doctor and patient versions as well as between ql - i items and the corresponding fact - g subscales ( ql - id and ql - ip activity , daily living and health and fwb ; ql - id and ql - ip support and sfw ) , ( table 5 ) . \n correlation between the fact - g and the poms - sf total mood disturbance score ( poms tmd ) is also relatively high . \n as expected , the correlation coefficients between the fact - g total and subscale scores and the mcsds-10 are low . \n correlation between fact - g , qli doctor and patient version , poms - sf , mcsds-10 * * correlation is significant at the 0.01 level . * \n the results of rasch analyses confirmed the unidimensionality of each subscale of the fact - g with two exceptions ( see table 6 ) . \n gs7 ( i am satisfied with my sex life ) of the sfwb subscale had both mnsq fit statistics greater 1.40 , indicating it did not perform well with the other items in the same scale . \n ge2 ( i am satisfied with how i 'm coping with my illness ) of the ewb also had large mnsq fit statistics , indicating its poor fit to the unidimensionality model with the other items on the same scale . \n since most instruments designed to evaluate quality of life have been developed in the united states or in western europe , it is necessary to adapt them to be used in other cultural settings . \n thus , it is important to produce a culturally equivalent measure that can be used to accurately evaluate different groups of people . \n the final step in the complex process of cross - cultural adaptation is to validate the instrument through the study of the psychometric properties of the measure . \n a validation study of the fact - g spanish version 4 was conducted in a sample of uruguayan cancer patients . \n a large variability in the biological and sociodemographic features of the sample was ensured to study the general performance of the questionnaire . \n the frequency of tumor sites represents very closely the incidence of solid tumors in the uruguayan general population . \n reliability analysis showed high internal consistency as indicated by cronbach alpha coefficients ranging from ( .78 .91 ) . \n the comparison of these data with the results obtained from the fact - g english and spanish version 2 ( table 2 ) points out a remarkable improvement in fact - g spanish version 4 total scale as well as subscale reliability coefficients . \n based on these results it is safe to conclude that the fact - g spanish version 4 shows sufficient internal consistency to justify its use across cultures . as an evidence of construct validity , the fact - g questionnaire appeared to be capable of discriminating among groups of patients according to their level of performance status , showing differences in the total scale and subscale scores with the criterion groups . \n the fact - g total and the functional well - being subscale showed the best discriminative ability . \n differences among known groups were also observed in the fact - g total and subscale scores in relation to in - patients vs. out - patients . \n as expected , the fact - g scores are higher ( better qol ) among outpatients and differences were statistically significant on the functional , social and emotional well - being subscales . quality of life researchers have been concerned about the clinical significance of measures and have pursued the objective to find practical and comprehensive criteria that could be interpretable by clinicians when conveying research results . clinical status and disease characteristics \n differences ranging from 5 to10 points in the overall scale and of approximately 3 points in the physical and functional subscales can be considered clinically relevant since they can discriminate between patients with loco regional and metastatic diseases , a clear - cut criterion commonly used by oncologists . accordingly , effect size calculations showed moderate values ranging from 0.30 to 0.60 . \n these findings are consistent with those found in a longitudinal study using the fact - g to assess treatment outcomes in a sample of advanced lung cancer patients . in ctt , \n the most common form of construct validation of hrql measures has been the study of convergent and discriminant validity . \n we included it in our study , along with the more recent irt approach , because it provides relevant information on the relationship of the questionnaire with other measures of qol and related constructs , i.e. , performance status or psychological distress after a priori hypothesis were made about the magnitude and direction of the correlations . \n as an evidence of convergent validity , moderate but significant , correlations were found between the fact - g and a set of instruments ( ecog psr , ql - i and poms - sf ) that are expected a priori to be related to qol assessments while no correlation was found between the fact - g and the mcsds-10 , supporting divergent validity . \n an important issue to be considered is the technical equivalence of the fact - g when used in a sample of cancer patients of a south american country . as mentioned earlier , most patients in the uruguayan sample preferred the questionnaire to be read out loud by an interviewer instead of filling it out by themselves . \n these may raise the issue as to whether this difference in the method of assessment is comparable in each culture with respect to the data that it yields . in our study , \n the internal consistency of the fact - g did not vary when studied separately , by means of the cronbach alpha coefficients for the fact - g total and subscale scores for two groups of patients . in a study of the impact of socio - cultural and clinical factors on hispanic and african american cancer patients ' quality of life , wan et \n al also found no significant effect of the mode of administration of the fact - g on the reporting of overall qol . \n recently , audio - visual computerized based assessments of qol provide an innovative way for gathering and using self - report data and may be feasible for individuals with limited literacy skills ( hahn et al . unpublished data ) . based on the ctt approach \n , we may conclude that spanish fact - g version 4 is a psychometrically sound instrument to assess qol in the population being studied . \n however , in the present study , we moved on to introduce irt based analyses of the data considering the significant advantages shown by this method when used to evaluate health outcomes measures . \n despite the long history of ctt , there remain major limitations in some areas that have been summarized by hambleton . \n first of all , the ctt - based statistics that describe test performance are sample dependent . \n irt is more useful since it provides more robust item statistics that are independent and invariant over sample populations that vary in the trait measured by the test . \n another limitation of ctt is that the scores that are commonly used as a measure of the examinees ' ability are test dependent . \n potential advantages of using irt in health outcome assessments are : more comprehensive and accurate evaluation of item characteristics , assessment of group differences in item and scale functioning , evaluation of scales containing items with different response formats , improvement of existing measures , computer adaptive testing ( cat ) applications , and evaluation of person fit . \n thus , irt can facilitate the development of new items and scales to improve exiting measures . \n it may raise attention on redundant items or the location along the trait continuum ( in our case , quality of life ) where the scale provides little information and needs to be improved . \n an irt analysis was included in the evaluation of fact - g spanish version 4 because it provides additional information on the reliability of the scale than that provided by the ctt approach . \n a rating scale model ( rsm ) was used which assumes that the logit - transformed measures of the item scores within each subscale vary along the latent trait level ( quality of life ) and are aligned according to the difficulty ( or location ) the patients had to endorse each item , with negative values representing those items that are easier to endorse and positive values those that are more difficult . in the present study , item fit statistics confirmed the unidimensionality of each subscale with two exceptions . in the case of gs7 ( i am satisfied with my sex life ) , many patients were reluctant to give information about their sexual life and this may be a cause of inconsistency in their responses . \n another reason for discrepancy may be related to some problem in translation or comprehension . in both items ( gs7 and ge2 ) the word \" satisfaction \" was translated into spanish as \" satisfaccin \" which implies in spanish a degree of fulfillment that patients may be not prone to express when answering such question . \n another possible explanation is that these items are the only ones phrased positively in their respective subscales while the rest of the items refer to negative conditions for quality of life . \n for instance , the graded response model ( grm ) , an extension of the two parameter logistic model is also appropriate to use when item responses can be characterized as ordered categorical responses . \n however , scores obtained using several models were highly correlated showing that these approaches yield comparable results . \n irt analyses demands large sample sizes in order to obtain stable and invariant item and latent trait estimates . however , several studies using this procedure to assess the psychometric properties of qol measures addressed rather small sample of patients ( range : 100 to 400 patients ) [ 32 - 37 ] . \n cella and chang warned of the possible limitations of using irt methods in the evaluation of health measures since they were originally developed for and used with a fairly homogeneous educational assessment population . \n when we apply these methods to more heterogeneous clinical populations there may be limitations to obtain item - free estimates of sample latent traits . \n they remark that the context , selection and sequence of questions , considering both item diversity and clinical diversity , may produce sample - dependent item difficulty estimates and therefore unreliable item - dependant estimates of patient ability . \n the continuous monitoring of item calibrations involved in the process of item banking will help to solve these uncertainties . \n the present study is the first one in south america reporting results on item functioning on a health related quality of life measure . \n future studies with larger sample of patients could lead to a better understanding of differences in item functioning across different south american countries and cultures and move forward to item banking and cat technology suitable for developing countries . \n we conclude that the fact - g spanish version 4 showed , using classic psychometric and irt approaches , good reliability and validity and is a valid instrument to set clinical significant differences in longitudinal studies of cancer treatment . \n g spanish language version , as reported here , provides sufficient assurance of equivalence to its original english version to be used in future research on quality of life among south american spanish speaking patients . \n jjd conceived of the study , participated in its design and coordination , statistical analyses , preparation of drafts and the final manuscript . \n chc performed irt based analysis and interpreted results , assisted in the preparation and revision of the manuscript . \n this study was partially funded by the comisin honoraria de lucha contra el cancer , uruguay . \n dr . dapueto 's research at the center on outcomes , research and education , evanston northwestern healthcare was supported by an international union against cancer icrett fellowship . \n david cella , ph.d . , and ignacio muse , m.d . for their cooperation and support .", "role": "user" }, { "content": "backgroundthe fact - g has gone through many validation studies . however \n , little research has been conducted in south american spanish speaking patients . the present study aimed to evaluate the fact - g spanish version 4 in uruguayan cancer patients.methodsthe data analyzed \n were collected from 309 patients , with various tumor sites , at different stages of disease and receiving different treatments.resultsreliability was evaluated using cronbach 's coefficient alpha and showed high internal consistency for each of the subscales and its total scale ( range = .78 .91 ) of the fact - g . \n the fact - g total score also showed significant mean differences among known groups ( performance status , in vs. outpatients ) when tested by anova and t - test . \n when the tumor stage ( local and regional vs. metastatic disease ) was used as a clinical anchor , the fact - g total score , the physical well - being ( pwb ) , and functional well - being ( fwb ) subscale scores showed mean differences , ranging from 5 to 10 points in a scale from 0108 ( effect sizes = 0.300.60 ) . \n item response theory ( irt)-based evaluation using mean square fit statistics ( .601.4 ) criteria showed that only two items misfit : \" estoy satisfecho(a ) con mi vida sexual \" ( i am satisfied with my sex life ) and \" estoy satisfecho(a ) de cmo estoy enfrentando mi enfermedad \" ( i am satisfied with how i am coping with my illness).conclusionthe results indicated that , using both traditional and irt approaches , the spanish fact - g has good reliability and validity to be used as a qol instrument among uruguayan cancer patients .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: data were derived from the depression and myocardial infarction study ( depremi ) ( 18 ) and the myocardial infarction and depression - intervention trial ( mind - it ) ( 19 ) . in these multicenter studies , 528 and 2,176 mi patients , respectively , were screened for depression . \n patients were recruited from 14 hospitals ( including 4 university hospitals ) located in different parts of the netherlands . \n patients were included from september 1997 through september 2000 in depremi and from october 1999 through november 2002 in mind - it if they met established criteria for mi ( 20 ) . \n exclusion criteria were cognitive dysfunction , not being able to speak or read dutch , hospitalization for other reasons than mi ( except angina pectoris ) , and a life expectancy of < 1 year as a result of noncardiovascular disease . in mind - it , patients were also excluded if they were already receiving psychiatric treatment for a current depressive episode ( n = 104 ) . \n because the two studies were highly comparable in patient recruitment , inclusion and exclusion criteria , and depression assessment , data of both studies were combined for the present analyses . \n both studies were approved by the local ethical committee of the participating hospitals , and all patients gave informed consent . in patients who were hospitalized for index - mi , we assessed depression with the 21-item beck depression inventory ( bdi ) , using bdi scores 10 to indicate depression . \n the bdi is a validated instrument for depression , and bdi scores 10 are considered to signify at least mild depression ( 21 ) . \n the presence of diabetes was based on either self - reported diagnosis at admission , which was verified by the medical chart , or a new diagnosis at discharge for which medication was necessary . \n mortality records up until 31 december 2007 were provided by statistics netherlands through linkage to the municipal personal records database . \n secondary outcome was death from cardiac disease as primary cause of death ( cardiac mortality ) , based on icd-10 ( codes i11 , i20i25 , i42i50 , and r57.0 ) in the mortality records . \n demographic , lifestyle , and cardiovascular data were collected during hospitalization for index - mi and included age , sex , smoking status , hypertension , left ventricular ejection fraction ( lvef ) , prior mi , and killip class . \n killip class was determined at hospital admission , with a standardized 4-point clinical assessment of the degree of heart failure , based on pulmonary rales and x - ray . \n killip class was divided in two categories ( class 1 and class 2 , 3 , or 4 ) . \n we classified the patients according to their diabetes and depression status into the following four categories : 1 ) no diabetes , no depression ; 2 ) diabetes , no depression ; 3 ) no diabetes , depression ; and 4 ) diabetes , depression . \n first , we evaluated with multinomial regression whether baseline characteristics for groups 2 to 4 differed significantly from group 1 ( no diabetes , no depression ) . \n next , we assessed time to all - cause and cardiac mortality using cox regression models , in a crude model , and after adjusting for a priori defined covariates , in a stepwise approach : 1 ) age and sex ; 2 ) age , sex , hypertension , and smoking ; and 3 ) age , sex , hypertension , smoking , lvef , prior mi , and killip class . \n the group without diabetes and depression served as reference group . to illustrate the relationships between depression and diabetes with mortality , we plotted kaplan - meier curves for each diabetes and depression category \n biological interaction refers to a deviation from additivity of two or more causes of disease that together influence the disease outcome ( 22 ) . in cox regression analysis , \n biological interaction differs from statistical interaction because in cox regression models , statistical interaction is implicitly exponential and therefore multiplicative . \n we tested whether biological interaction had occurred using the relative excess risk due to interaction ( reri ) ( 22 ) by using the method outlined by andersson et al . \n reri represents the risk that is in excess of what would be expected if the combination of two risk factors would be purely additive ( e.g. , no synergism ) . \n we adjusted for the same sets of covariates as described for the cox regression models . \n missing values for the variables used in the statistical analyses were assumed to be missing at random and were multiply imputed using imputation by chained equations . \n variables used to impute datasets were diabetes , log - transformed bdi score at baseline , log - transformed bdi score at 3 months , factor scores for somatic / affective depressive symptoms and cognitive / affective depressive symptoms , mortality , log - transformed time to mortality , age , sex , hypertension , smoking , lvef , prior mi , killip class , bmi , study , location of mi , hypercholesterolemia , family history of coronary artery disease , rehospitalization , and log - transformed time to rehospitalization . the numbers and hazard ratios ( hrs ) reported in this study were based on the multiply imputed datasets . \n the numbers were averaged over the 10 imputed datasets . although mortality data were used to create the imputed datasets , cases with imputed mortality data were excluded from the cox regression analysis as recommended by von hippel ( 25 ) . \n we also did an available - case analysis in which we repeated the cox regression analysis with the existing data . \n we tested statistical interaction between depression and diabetes for mortality by testing the significance of the interaction term depression - diabetes as a supplementary analysis . \n analyses were performed in stata 10.1 ( statacorp . , college station , tx ) . \n in patients who were hospitalized for index - mi , we assessed depression with the 21-item beck depression inventory ( bdi ) , using bdi scores 10 to indicate depression . \n the bdi is a validated instrument for depression , and bdi scores 10 are considered to signify at least mild depression ( 21 ) . \n the presence of diabetes was based on either self - reported diagnosis at admission , which was verified by the medical chart , or a new diagnosis at discharge for which medication was necessary . \n mortality records up until 31 december 2007 were provided by statistics netherlands through linkage to the municipal personal records database . \n secondary outcome was death from cardiac disease as primary cause of death ( cardiac mortality ) , based on icd-10 ( codes i11 , i20i25 , i42i50 , and r57.0 ) in the mortality records . for this outcome \n demographic , lifestyle , and cardiovascular data were collected during hospitalization for index - mi and included age , sex , smoking status , hypertension , left ventricular ejection fraction ( lvef ) , prior mi , and killip class . \n killip class was determined at hospital admission , with a standardized 4-point clinical assessment of the degree of heart failure , based on pulmonary rales and x - ray . \n killip class was divided in two categories ( class 1 and class 2 , 3 , or 4 ) . \n in patients who were hospitalized for index - mi , we assessed depression with the 21-item beck depression inventory ( bdi ) , using bdi scores 10 to indicate depression . \n the bdi is a validated instrument for depression , and bdi scores 10 are considered to signify at least mild depression ( 21 ) . \n the presence of diabetes was based on either self - reported diagnosis at admission , which was verified by the medical chart , or a new diagnosis at discharge for which medication was necessary . \n mortality records up until 31 december 2007 were provided by statistics netherlands through linkage to the municipal personal records database . \n secondary outcome was death from cardiac disease as primary cause of death ( cardiac mortality ) , based on icd-10 ( codes i11 , i20i25 , i42i50 , and r57.0 ) in the mortality records . \n demographic , lifestyle , and cardiovascular data were collected during hospitalization for index - mi and included age , sex , smoking status , hypertension , left ventricular ejection fraction ( lvef ) , prior mi , and killip class . \n killip class was determined at hospital admission , with a standardized 4-point clinical assessment of the degree of heart failure , based on pulmonary rales and x - ray . \n killip class was divided in two categories ( class 1 and class 2 , 3 , or 4 ) . \n we classified the patients according to their diabetes and depression status into the following four categories : 1 ) no diabetes , no depression ; 2 ) diabetes , no depression ; 3 ) no diabetes , depression ; and 4 ) diabetes , depression . \n first , we evaluated with multinomial regression whether baseline characteristics for groups 2 to 4 differed significantly from group 1 ( no diabetes , no depression ) . \n next , we assessed time to all - cause and cardiac mortality using cox regression models , in a crude model , and after adjusting for a priori defined covariates , in a stepwise approach : 1 ) age and sex ; 2 ) age , sex , hypertension , and smoking ; and 3 ) age , sex , hypertension , smoking , lvef , prior mi , and killip class . \n the group without diabetes and depression served as reference group . to illustrate the relationships between depression and diabetes with mortality , we plotted kaplan - meier curves for each diabetes and depression category . furthermore , we tested whether biological interaction had occurred . \n biological interaction refers to a deviation from additivity of two or more causes of disease that together influence the disease outcome ( 22 ) . in cox regression analysis , \n biological interaction differs from statistical interaction because in cox regression models , statistical interaction is implicitly exponential and therefore multiplicative . \n we tested whether biological interaction had occurred using the relative excess risk due to interaction ( reri ) ( 22 ) by using the method outlined by andersson et al . \n reri represents the risk that is in excess of what would be expected if the combination of two risk factors would be purely additive ( e.g. , no synergism ) . \n we adjusted for the same sets of covariates as described for the cox regression models . \n missing values for the variables used in the statistical analyses were assumed to be missing at random and were multiply imputed using imputation by chained equations . \n variables used to impute datasets were diabetes , log - transformed bdi score at baseline , log - transformed bdi score at 3 months , factor scores for somatic / affective depressive symptoms and cognitive / affective depressive symptoms , mortality , log - transformed time to mortality , age , sex , hypertension , smoking , lvef , prior mi , killip class , bmi , study , location of mi , hypercholesterolemia , family history of coronary artery disease , rehospitalization , and log - transformed time to rehospitalization . the numbers and hazard ratios ( hrs ) reported in this study were based on the multiply imputed datasets . \n the numbers were averaged over the 10 imputed datasets . although mortality data were used to create the imputed datasets , cases with imputed mortality data were excluded from the cox regression analysis as recommended by von hippel ( 25 ) . \n we also did an available - case analysis in which we repeated the cox regression analysis with the existing data . \n we tested statistical interaction between depression and diabetes for mortality by testing the significance of the interaction term depression - diabetes as a supplementary analysis . \n analyses were performed in stata 10.1 ( statacorp . , college station , tx ) . \n missing data of depression and diabetes were multiply imputed for 236 patients ( 9% ) and 15 patients ( < 1% ) , respectively . at baseline , \n 1,789 patients ( 66% ) had no diabetes and no depression , 224 patients ( 8% ) had diabetes but no depression , 585 patients ( 22% ) had depression but no diabetes , and 106 patients ( 4% ) had both diabetes and depression . \n those with both diabetes and depression were on average less healthy and had a worse cardiovascular risk profile but were less often current smokers than patients without diabetes and depression . \n table 1 also shows the percentage of missing values that were imputed per baseline variable , which varied between 0 and 9% . \n baseline characteristics for the four diabetes and depression categories using the multiple imputed datasets ( n = 2,704 ) for 179 patients ( 7% ) , data on mortality could not be retrieved . \n additional analyses showed that these patients did not differ from those with mortality data regarding presence of depression , diabetes , and the other covariates , except for prior mi . there was a higher prevalence of prior mi in patients whose mortality data could not be retrieved ( 21 vs. 14% , p = 0.005 ) . of the remaining 2,525 patients with data on mortality , \n a total of 439 participants ( 17% ) died during follow - up , of which 175 ( 7% ) were classified as cardiac death . \n the all - cause mortality rate was 14% ( 226 of 1,673 ) for patients without depression and without diabetes , 23% ( 49 of 210 ) for patients with diabetes only , 22% ( 118 of 544 ) for patients with depression only , and 47% ( 46 of 98 ) for patients with both depression and diabetes . \n the mean follow - up time for the participants was 6.2 years ( sd 2.0 ) . \n figures 1 and 2 show the kaplan - meier curves for all - cause and cardiac mortality for each strata of diabetes and depression . \n table 2 shows the number of deaths and the hrs for all - cause and cardiac mortality across the four categories of diabetes and depression . \n for all - cause mortality , the hr was 4.58 ( 95% ci 3.296.37 ) for the patients with both diabetes and depression in the unadjusted analyses compared with the reference group ( patients without diabetes and without depression ) . \n the strength of the relationship with mortality decreased to some extent after adjustment for the potential confounders ( age , sex , smoking , hypertension , lvef , previous mi , and killip class ) but remained significant . \n furthermore , post hoc comparisons showed that the hr in those with both diabetes and depression was higher compared with patients with diabetes only ( full model : 2.10 [ 1.383.21 ] ) and depression only ( full model : 2.08 [ 1.462.98 ] ) . \n the association between diabetes , depression , and mortality did not differ by sex ; the interaction terms of the diabetes depression categories with sex were not statistically significant . \n the hr for cardiac mortality in the diabetes and depression group was 5.77 ( 3.539.43 ) in the unadjusted model and 3.27 ( 1.975.41 ) in the fully adjusted model . \n post hoc comparisons showed that the hr in patients with both diabetes and depression was higher compared with patients with diabetes only ( full model : 2.54 [ 1.324.89 ] ) and depression only ( full model : 2.10 [ 1.253.54 ] ) . \n kaplan - meier curves for all - cause mortality for each diabetes and depression category ( unadjusted analysis ) . \n kaplan - meier curves for cardiac mortality for each diabetes and depression category ( unadjusted analysis ) . \n number of deaths and hrs for all - cause and cardiac mortality for the four diabetes and depression categories when we repeated the cox regression analysis as an available - case analysis in the nonimputed dataset , approximately similar results were found ( data not shown ) . \n for example , the hr for all - cause mortality in the fully adjusted model was 1.37 ( 95% ci 0.951.98 ) for those with diabetes only , 1.32 ( 1.021.71 ) for those with depression only , and 3.23 ( 2.254.64 ) for those with both diabetes and depression compared with those without diabetes and depression in the available - case analysis . \n for all - cause mortality , the reri was 1.94 ( 95% ci 0.373.51 ) in the unadjusted analyses and 1.13 ( 0.122.14 ) in the fully adjusted analyses . \n this exceeds the value 0 and , thus , suggests a positive interaction between diabetes and depression as departure from additivity . \n this means that the joint effect of diabetes and depression is significantly larger than the sum of the individual effects of diabetes and depression , even after controlling for confounders . for cardiac mortality \n , there was a trend for a positive additive interaction between diabetes and depression , but this was not statistically significant ( unadjusted analysis : 2.90 [ 0.02 to 5.82 ] ; fully adjusted analysis : 1.42 [ 0.21 to 3.06 ] ) . \n we tested formal statistical ( multiplicative ) interaction between depression and diabetes for mortality . although the direction of the multiplicative interaction was positive , this interaction was not significant for all - cause mortality ( range p = 0.100.20 across the models ) and cardiac mortality ( range p = 0.210.30 across the models ) . \n for all - cause mortality , the reri was 1.94 ( 95% ci 0.373.51 ) in the unadjusted analyses and 1.13 ( 0.122.14 ) in the fully adjusted analyses . \n this exceeds the value 0 and , thus , suggests a positive interaction between diabetes and depression as departure from additivity . \n this means that the joint effect of diabetes and depression is significantly larger than the sum of the individual effects of diabetes and depression , even after controlling for confounders . for cardiac mortality \n , there was a trend for a positive additive interaction between diabetes and depression , but this was not statistically significant ( unadjusted analysis : 2.90 [ 0.02 to 5.82 ] ; fully adjusted analysis : 1.42 [ 0.21 to 3.06 ] ) . \n although the direction of the multiplicative interaction was positive , this interaction was not significant for all - cause mortality ( range p = 0.100.20 across the models ) and cardiac mortality ( range p = 0.210.30 across the models ) . \n this is the first study that aimed to investigate the association of coexisting diabetes and depression with mortality after mi . \n we observed an increased mortality risk in patients with both diabetes and depression who were hospitalized for mi , beyond the association with mortality for diabetes and depression alone . \n this association weakened somewhat but remained statistically significant after adjustment for demographic and established prognostic cardiac factors . \n most striking , there was a synergistic additive interaction between diabetes and depression for mortality , which weakened but remained statistically significant after adjusting for cardiac disease severity . \n our results are similar to population - based , epidemiological studies that suggest a possible synergistic interaction between diabetes and depression or psychological distress for mortality ( 8,1517,26 ) . \n although the absolute mortality rate in this high - risk group for mortality was considerably higher , the strength of the association of diabetes and depression with mortality is within the range of associations observed in the population - based studies . \n it is known that diabetic patients with depression have more diabetes - related complications ( such as diabetic retinopathy , nephropathy , and neuropathy ) ( 27 ) and are more often in poor glycemic control , as denoted by elevated levels of glycated hemoglobin ( hba1c ) ( 28 ) , than diabetic patients without depression . in a population study of people with psychological distress and diabetes , \n on the other hand , hba1c levels appeared to be related to mortality in a study with mi patients , both in nondiabetic patients and in diabetic patients ( 29 ) . \n depression is known to be related to a reduced adherence to self - care behaviors ( i.e. , diet , exercise , and smoking cessation ) and to reduced medication adherence in diabetic as well as mi patients ( 30,31 ) . not only major depression but also subthreshold depression is associated with nonadherence to different aspects of diabetes self - care ( 32 ) . for mi patients with diabetes , \n poorer self - care might be more deleterious compared with mi patients without diabetes because of the many and often complex self - care activities involved in diabetes management . \n furthermore , depression is related to several biological changes , such as increased inflammation and dysfunction of the autonomic nervous system , which in turn are related to increased cardiovascular mortality ( 33 ) . \n second , we found that part of the excess risk associated with the coexistence of diabetes and depression was explained by the baseline cardiac disease severity parameters . \n specifically , patients with both diabetes and depression had worse physical health to start with , such as more peripheral vascular disease and cerebrovascular disease . \n it is unclear whether this represents confounding ( i.e. , that depression and diabetes may serve as a risk indicator for mi patients with a poor clinical profile ) or whether this is already a consequence of the diabetes - depression interaction . \n a possible explanation for these findings rests on the premise that depression may have a different etiology in diabetic patients compared with patients without diabetes . \n diabetes and depression share several metabolic alterations in proinflammatory cytokines , glucocorticoid signaling , and cellular respiration ( 34 ) . \n the combination of diabetes and depression in mi patients might be an expression of such metabolic alterations and may therefore be associated with a poorer cardiac prognosis . \n this is in line with the many reports on the association of proinflammatory cytokines with the development and progression of a cardiac disease , including increased mortality risk ( 35,36 ) . \n what are the clinical implications of our findings ? in the next decades , an immense increase in the prevalence of type 2 diabetes is expected to occur . \n because the prevalence of depression in patients with type 2 diabetes is almost twice that of nondiabetic people ( 7 ) , both diabetes and depression will become highly prevalent health problems in mi patients . \n physicians should be aware that mi patients with diabetes and depression have an increased mortality risk . \n however , there is an ongoing debate whether screening for depression will benefit the patients prognosis . \n although identification can be useful , there are no studies showing that screening alone improves depressive symptoms and cardiac outcomes ( 37 ) or diabetes outcomes ( 38 ) in patients with cardiovascular disease or diabetes , respectively . \n recently , a nurse - led collaborative care management for primary care patients with poorly controlled diabetes and/or coronary artery disease and depression was evaluated ( 39 ) . \n the intervention group had improved with respect to blood pressure , hba1c , and depression after 12 months , which are factors that are known to be related to increased mortality ( 39 ) . \n it may be worthwhile to monitor mi patients with both diabetes and depression closely to evaluate their mood , adherence to treatment regimens , and compliance with lifestyle recommendations , such as enhancing physical activity . \n it might be relevant to investigate whether our results can be replicated in countries with a higher prevalence of diabetes in mi patients . \n first , our large cohort of mi patients and long follow - up period made it possible to study the effect of the coexistence of diabetes and depression on mortality . \n finally , by merging our data with the national mortality records , reliable and high - quality data of the primary cause of death could be retrieved . \n a limitation of our study was the use of depression questionnaires instead of diagnostic interviews . \n however , the bdi has been validated in mi patients against a structural clinical interview for depression ( 40 ) . in mind - it , patients with psychiatric treatment for depression during screening were excluded . \n furthermore , depression was measured during hospitalization , and we did not have data on lifetime depression for the majority of our patients . \n finally , we did not assess other relevant diabetes - related aspects ( hba1c and diabetes complications ) or self - care behaviors ( physical activity and medication adherence ) that might help to explain our findings . \n to conclude , we found that the coexistence of diabetes and depression after mi is related to increased mortality , beyond the effect on mortality of diabetes and depression alone in mi patients . \n first , our large cohort of mi patients and long follow - up period made it possible to study the effect of the coexistence of diabetes and depression on mortality . \n second , both demographic and cardiac risk factors were included as confounders . finally , by merging our data with the national mortality records , reliable and high - quality data of the primary cause of death could be retrieved . \n a limitation of our study was the use of depression questionnaires instead of diagnostic interviews . \n however , the bdi has been validated in mi patients against a structural clinical interview for depression ( 40 ) . in mind - it , patients with psychiatric treatment for depression during screening were excluded . \n furthermore , depression was measured during hospitalization , and we did not have data on lifetime depression for the majority of our patients . \n finally , we did not assess other relevant diabetes - related aspects ( hba1c and diabetes complications ) or self - care behaviors ( physical activity and medication adherence ) that might help to explain our findings . \n to conclude , we found that the coexistence of diabetes and depression after mi is related to increased mortality , beyond the effect on mortality of diabetes and depression alone in mi patients .", "role": "user" }, { "content": "objectivediabetes and depression are both linked to an increased mortality risk after myocardial infarction ( mi ) . population - based studies suggest that having both diabetes and depression results in an increased mortality risk , beyond that of having diabetes or depression alone . \n the purpose of this study was to examine the joint association of diabetes and depression with mortality in mi patients.research design and methodsdata were derived from two multicenter cohort studies in the netherlands , comprising 2,704 patients who were hospitalized for mi . \n depression , defined as a beck depression inventory score 10 , and diabetes were assessed during hospitalization . \n mortality data were retrieved for 2,525 patients ( 93%).resultsduring an average follow - up of 6.2 years , 439 patients died . \n the mortality rate was 14% ( 226 of 1,673 ) in patients without diabetes and depression , 23% ( 49 of 210 ) in patients with diabetes only , 22% ( 118 of 544 ) in patients with depression only , and 47% ( 46 of 98 ) in patients with both diabetes and depression . \n after adjustment for age , sex , smoking , hypertension , left ventricular ejection fraction , prior mi , and killip class , hazard ratios for all - cause mortality were 1.38 ( 95% ci 1.001.90 ) for patients with diabetes only , 1.39 ( 1.101.76 ) for patients with depression only , and as much as 2.90 ( 2.074.07 ) for patients with both diabetes and depression.conclusionswe observed an increased mortality risk in post - mi patients with both diabetes and depression , beyond the association with mortality of diabetes and depression alone .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: patients with long - standing type 2 diabetes mellitus often develop diabetic retinopathy in later life.1 commonly seen signs and symptoms of diabetic retinopathy include visible lesions on the retina ( microaneurysms , hemorrhages , and axoplasmic deposits ) , distorted central vision due to diabetic macular edema , and regions of dimmed or missing vision ( scotomas).2 nonproliferative diabetic retinopathy is the most prevalent form of the disease , although more advanced proliferative forms of diabetic retinopathy occur with neovascularization and substantial visual deficits.2 a major research goal in ophthalmology has been to discover inexpensive and effective treatments for diabetic retinopathy , particularly at an early stage of the disease when good vision is still present . however , reducing or eliminating predisposing factors such as smoking , poor diet , obesity , hypertension , and lack of exercise is essential in reducing the incidence of diabetes mellitus and diabetic retinopathy.3 many of the signs and symptoms of diabetes mellitus are caused by elevated levels of plasma homocysteine , a sulfur - containing intermediate metabolic product of the essential amino acid , methionine , that circulates throughout the body by way of the vascular system.4 normally , homocysteine is metabolically catalyzed to cysteine by various enzymes that are dependent on the b vitamins,57 and cysteine is converted to glutathione , a powerful antioxidant . however \n , when homocysteine is incorporated into proteins by a disulfide or amide linkage ( s - homocysteinylation or n - homocysteinylation ) , it creates a product that generates significant oxidative stress and inflammation throughout the body.4 an elevated level of homocysteine is known to be toxic to the pericytes and endothelial cells lining the wall of blood vessels , and can lead to vascular thrombosis and microaneurysms . \n individuals with diabetes mellitus are in a particularly high - risk group for elevated homocysteine , and over time they tend to exhibit the signs and symptoms associated with vascular wall cell damage from oxidative stress . \n for example , reduced vitamin b availability has been associated with sensory and peripheral motor nerve dysfunction in diabetes mellitus.8 in particular , individuals with long - term or poorly controlled diabetes often experience diabetic peripheral neuropathy in the distal portions of the limbs where blood circulation is poorest . \n likewise , diabetics have an increased mortality risk associated with cardiovascular disease , either due to or exacerbated by the presence of homocysteine.7,9 vitamins b6 , b9 , and b12 are known to be essential for maintaining the overall integrity of the vascular system , with b9 ( folate ) also contributing to adequate absorption of other essential nutrients . \n the effective use of vitamin b supplements has been described for prevention of cardiovascular disease in patients with kidney disease.10 likewise , it has been reported that patients taking vitamin b supplements , in particular folate , have significant improvement in their signs and symptoms of diabetic peripheral neuropathy.1117 a commercially available vitamin b compound reported to reduce anesthesia , paresthesia , causalgia , and other symptoms of homocysteine associated with vascular damage is metanx ( pamlab , covington , la , usa ) . \n metanx is a biologically active formulation of vitamin b that does not have to be processed by the liver as would be the case for over - the - counter synthetic vitamins . \n it is labeled as a medical food by the us food and drug administration and is available only by prescription . \n each metanx tablet contains 3 mg of l - methylfolate calcium ( vitamin b9 as metafolin , merck kgaa , darmstadt , germany ) , 35 mg pyridoxal-5-phosphate ( vitamin b6 ) , and 2 mg of methylcobalamin ( vitamin b12 ) . \n a standard daily dose of metanx is two tablets . in a study of intervention using metanx in 11 patients with diabetic peripheral neuropathy , \n 82% of patients reported improvement in sensory function and 73% had improved epidermal nerve fiber density based on tissue punch biopsies.14 in a more recent study of patients with diabetic peripheral neuropathy plasma homocysteine was decreased by 2.7 3.0 mol / l from baseline in a metanx intervention group as compared with a 0.5 2.4 mol / l increase in homocysteine in the control group ( p = 0.0001 ) over a six - month period.17 given that multiple independent studies have shown that a majority of patients with diabetic peripheral neuropathy have been helped by vitamin b intervention with no significant side effects , we hypothesized that patients with nonproliferative diabetic retinopathy may also be helped with respect to their visual function ( reduced scotomas ) and/or retinal physiology ( reduced diabetic macular edema ) . in order to establish preliminary evidence of the efficacy of vitamin b in treating nonproliferative diabetic retinopathy , and to estimate the sample size for a larger \n , randomized placebo - controlled study of a vitamin b intervention , several patients with nonproliferative diabetic retinopathy newly prescribed metanx were followed for up to six months . \n this prospective , open - label , single - arm study was conducted in a private practice ophthalmology clinic in accordance with the tenets of the declaration of helsinki . \n informed consent using written materials and an interview process was obtained from known patients with nonproliferative diabetic retinopathy selected to be test subjects . \n test subjects were not paid to participate , but did receive the metanx vitamin b intervention at no cost during the course of the study . \n ten adult patients who were previously diagnosed by an experienced retinologist to have mild to moderate nonproliferative diabetic retinopathy in both eyes were recruited into the study as test subjects . \n the subjects agreed to take standard daily doses of metanx and to undergo monthly assessment of their health and vision using standard nonexperimental clinical devices and vision screening methods . \n selected participants did not have signs of significant ocular disease other than nonproliferative diabetic retinopathy and no significant health concerns other than type 2 diabetes mellitus . \n no restrictions were placed on participant age , gender , or racial background ; however , all were required to have well controlled diabetes , based on their most recent glycosylated hemoglobin ( hba1c ) records . \n none of the participants reported using tobacco products or alcohol during the course of the study . \n the eyes included in this study were not being treated with laser or antivascular endothelial growth factor injections , but were being monitored by regularly scheduled examinations . \n ocular and general physical health were assessed at baseline and on a monthly basis thereafter using standard clinical testing for evaluating vision and ocular pathology , including high - contrast best - corrected visual acuity , intraocular pressure ( iop ) by applanation tonometry ( tono - pen xl , reichert technologies , depew , ny , usa ) , threshold light sensitivity by macular microperimetry ( maia , centervue spa , padova , italy ) , and central retinal thickness by spectral - domain optical coherence tomography ( spectralis , heidelberg engineering , carlsbad , ca , usa ) . because of the small n value of this pilot study , the percent change relative to baseline values of the mean threshold sensitivity and the mean central retinal thickness were used as primary outcome indicators . \n the microperimetry device measured mean threshold sensitivity in db at 37 discrete locations within the central 10 degrees of the macula using a goldman iii stimulus target . according to the manufacturer , the background luminance of the microperimeter is 4 apostilb , with a maximum luminance of 1000 apostilb for the stimulus target ( 1.27 candelas / m and 318.47 cd / m , respectively ) . \n the device randomly presents the test target at different stimulus locations and varies the target luminance using a 42 staircase algorithm . \n the overall dynamic range of the maia device is 36 db , and the threshold between normal and subnormal vision is considered to be 25 db . \n mean central retinal thickness was measured in m in the central two degrees of the macula by spectral - domain optical coherence tomography . \n additional information about the general health of the subjects was gathered during the course of the study , including resting heart rate , blood pressure , body weight , and most recent hba1c readings . \n changes in medication , doses , diet , and health since the last visit were recorded . \n all quantitative data were recorded in spreadsheets , statistically analyzed , and plotted using sigmaplot version 11.0 ( systat software , san jose , ca , usa ) . because of the small n value of this pilot study , both eyes of each patient were tested and used for analysis , except where noted . \n in addition , because each eye in the study had different baseline values for retinal threshold sensitivity and retinal thickness , the month - to - month changes for each metric are expressed as percentages of change relative to the baseline value . by expressing change as a percentage from baseline \n however , the variance at baseline becomes zero by this adjustment , and statistical comparisons based on variance must then be computed based on the first month of treatment . \n intervention with biologically active vitamin b was in the form of a daily dose of metanx which began on the day following the baseline evaluation for subjects who were successfully recruited into the study . \n if a dose was missed , subjects were instructed to take the regular dose at the next scheduled time , but to maintain a record of any missed doses . at the end of each monthly evaluation \n one lost subject s chief complaint was of dyspepsia after taking the vitamin b tablet in the morning and that for another was of increased tingling sensation in the legs after being on metanx for two weeks . \n an increase in somatosensation after initiating metanx has been reported to be a temporary side effect attributed to an improvement in vascular and neurologic function . on the recommendation of the primary care physician , \n a third subject was lost to follow - up because of pneumonia requiring a period of hospitalization , at which point metanx was stopped . due to the washout of vitamin b during this dose interruption , \n best - corrected visual acuity readings are reported in log of the minimum angle of resolution ( logmar ) units . \n there was a small decline in best - corrected visual acuity during the study period ( equivalent to approximately three snellen letters ) , but this was not statistically significant given the overall variability between subjects . \n there were no significant changes to any of the biometric readings followed during the study , and in particular , there were no reported changes in hba1c readings , indicating that glucose was being controlled . \n none of the subjects reported a significant change to their overall health or diet during the course of the study . with the exception of an occasional missed dose \n fourteen eyes from seven patients were available for testing ; however , two eyes from two subjects ( 2/14 , 14% ) were not included in the final microperimetry analysis because of foveal edema that caused poor fixation of the microperimetry target and an inability to complete the maia examinations . \n a failure to complete examination meant that an accurate mean threshold sensitivity could not be computed for all stimulus points . \n figure 1 shows the group mean percent change in retinal threshold sensitivity relative to the baseline value . \n there is an initial two - month increase in sensitivity to threshold light stimuli of approximately 7% , followed by a plateau effect for the next three months . \n data for months 25 were significantly different from both the baseline data and the one - month data ( p < \n the microperimetry device was not available for data collection at the six - month period for all subjects due to unanticipated relocation of the instrument . because of the low n value ( only two eyes ) and high variance , the six - month data are not shown . \n figure 2 indicates a linear trend of decreasing central retinal thickness expressed as a percentage from baseline ( r = 0.625 ; p = 0.034 ; n = 14 for all test periods ) . \n while the overall change relative to baseline is small , the difference between the one - month and six - month data is significant ( p = 0.012 ; mann - whitney rank sum test ) and indicates an approximately 2% decline in mean central retinal thickness over this period . unlike the threshold sensitivity data \n fourteen eyes from seven patients were available for testing ; however , two eyes from two subjects ( 2/14 , 14% ) were not included in the final microperimetry analysis because of foveal edema that caused poor fixation of the microperimetry target and an inability to complete the maia examinations . \n a failure to complete examination meant that an accurate mean threshold sensitivity could not be computed for all stimulus points . \n figure 1 shows the group mean percent change in retinal threshold sensitivity relative to the baseline value . \n there is an initial two - month increase in sensitivity to threshold light stimuli of approximately 7% , followed by a plateau effect for the next three months . \n data for months 25 were significantly different from both the baseline data and the one - month data ( p < 0.001 ) using analysis of variance . \n the microperimetry device was not available for data collection at the six - month period for all subjects due to unanticipated relocation of the instrument . because of the low n value ( only two eyes ) and high variance , the six - month data are not shown . \n figure 2 indicates a linear trend of decreasing central retinal thickness expressed as a percentage from baseline ( r = 0.625 ; p = 0.034 ; n = 14 for all test periods ) . \n while the overall change relative to baseline is small , the difference between the one - month and six - month data is significant ( p = 0.012 ; mann - whitney rank sum test ) and indicates an approximately 2% decline in mean central retinal thickness over this period . unlike the threshold sensitivity data \n recent clinical studies have investigated homocysteine as a factor or cofactor involved in diabetic retinopathy,1827 as well as in other ocular diseases , including age - related macular degeneration,28,29 central retinal vein occlusion,30 and nonarteritic ischemic optic neuropathy.31 hyperglycemia during diabetes increases production of vascular superoxide , which inactivates expression of nitric oxide by endothelial cells and contributes to vascular degradation.13,32,33 therefore , intervention with vitamin b could make an important contribution toward enhancing the production of nitric oxide . \n a recent porcine animal model has demonstrated that homocysteine inhibits dilation of retinal arterioles via the nitric oxide - mediated pathway , and thereby facilitates development of retinal vascular disease , such as diabetic retinopathy.34 therefore , we believe that there is sufficient scientific evidence to suggest a role for homocysteine in vascular ocular disease , and that a study of vitamin b as an intervention in the management of diabetic retinopathy is warranted . in our pilot study , daily use of biologically active vitamin b over a period of several months resulted in a small but significant improvement in mean retinal threshold sensitivity for eyes with mild to moderate nonproliferative diabetic retinopathy . \n the increase in threshold sensitivity was distinctly nonlinear , with an initial two - month increase followed by a plateau at this elevated state . \n while nonlinear curves in subjective testing can sometimes be attributed to learning during testing , the simple nature of microperimetry examination usually limits learning to the first few presentations of the test stimulus . \n in addition , the combination of averaging many data points from each eye and the fact that examinations are separated by one - month intervals would tend to eliminate learning as a variable . \n therefore , the possibility exists that the presence of endogenous nitric oxide from vitamin b intervention could enhance photoreceptor activity and thereby enhance threshold sensitivity to light.35 this also might explain the early nonlinear improvement in threshold retinal sensitivity seen in this study . \n this study also reveals a small but significant decrease in mean retinal thickness of eyes with nonproliferative diabetic retinopathy . \n in contrast with the nonlinear response seen with mean threshold sensitivity , the reduction in central retinal thickness was essentially linear over the course of the study . any decrease in retinal thickness must be linked to both the repair of any sources of vascular leakage , as well as moving fluid out of the edematous tissue , which should be a relatively slow , linear process . \n therefore , we speculate that a significant reduction in homocysteine does not necessarily translate into an immediately significant effect on pre - existing diabetic macular edema . \n further , the ability of the retina to recover from pre - existing vascular damage will depend on the overall severity of the damage . \n consequently , there may be physiologic limits to the efficacy of vitamin b intervention to invoke repairs even if homocysteine can be decreased and the availability of nitric oxide increased . \n although our interpretation of the results of the study are speculative , it paves the way for future studies , and provides a connection to previous laboratory studies in animal models and human testing for the treatment of diabetic peripheral neuropathy . while the observed effect was small over a six - month period ( about 1.5% ) , when extrapolated over time , the result takes on more clinical significance . \n in addition , the majority of eyes examined had limited amounts of diabetic macular edema at baseline . \n are the lack of subject and observer masking , with a placebo control and a small n value . \n the introduction of a placebo control group will also require sampling data to be restricted to a single test eye . in the current study , we combined the results of both eyes in a manner analogous to the practice of combining skin biopsy data from both legs of a patient with diabetic neuropathy . \n the nature of retinopathy is such that vascular damage can be variable and randomly located across the retina . \n therefore , combining information from both eyes during observational studies can give a more complete assessment of functional damage to the total visual system in individuals with known disease . \n in such protocols , use of both eyes for data collection is acceptable.36 the current study was based on a dosage deemed to be safe and effective for the treatment of diabetic peripheral neuropathy . \n further study is needed to determine an appropriate dosage specifically for patients with diabetic retinopathy , and whether the dosage should be adjusted according to the severity of the diabetic retinopathy present . \n the current study does not address the use of other supplements that may be used synergistically with b vitamins in order to provide additional retinal protection or efficacy in the reversal of retinopathy signs and symptoms . \n finally , it would be helpful to have known whether the concentration of homocysteine was affected during the course of this study . \n elevated homocysteine levels have been found in the aqueous and vitreous humors of those afflicted with diabetic retinopathy , but such samples are impractical to obtain in living subjects except under unique circumstances.23,25 tracking of systemic homocysteine can be done by blood analysis , and future testing of vitamin b intervention for diabetic retinopathy should include this parameter.2022 \n the current protocol has the limitations typical of any clinical pilot study . among these are the lack of subject and observer masking , with a placebo control and a small n value . \n the introduction of a placebo control group will also require sampling data to be restricted to a single test eye . in the current study , we combined the results of both eyes in a manner analogous to the practice of combining skin biopsy data from both legs of a patient with diabetic neuropathy . \n the nature of retinopathy is such that vascular damage can be variable and randomly located across the retina . \n therefore , combining information from both eyes during observational studies can give a more complete assessment of functional damage to the total visual system in individuals with known disease . \n in such protocols , use of both eyes for data collection is acceptable.36 the current study was based on a dosage deemed to be safe and effective for the treatment of diabetic peripheral neuropathy . \n further study is needed to determine an appropriate dosage specifically for patients with diabetic retinopathy , and whether the dosage should be adjusted according to the severity of the diabetic retinopathy present . \n the current study does not address the use of other supplements that may be used synergistically with b vitamins in order to provide additional retinal protection or efficacy in the reversal of retinopathy signs and symptoms . \n finally , it would be helpful to have known whether the concentration of homocysteine was affected during the course of this study . \n elevated homocysteine levels have been found in the aqueous and vitreous humors of those afflicted with diabetic retinopathy , but such samples are impractical to obtain in living subjects except under unique circumstances.23,25 tracking of systemic homocysteine can be done by blood analysis , and future testing of vitamin b intervention for diabetic retinopathy should include this parameter.2022 \n preliminary data indicate that intervention with biologically active vitamin b may influence the progression of nonproliferative diabetic retinopathy , presumably through the metabolic pathway of homocysteine . \n a reduction of homocysteine may permit a physiologic environment more suitable for the repair of vascular structures of the retina ; however , it may be impossible to repair severely damaged tissue fully . \n nevertheless , interventions that help to protect the eye and retain existing vision are critical for those with diabetes . \n both mean retinal threshold sensitivity and mean central retinal thickness were significantly improved by two and six months , respectively ; however , the limited nature of this pilot study prevented us from eliminating potential confounding factors that could contribute to type i error , such as a placebo effect or a greater awareness in subjects of their overall health during the study . \n the study also did not allow us to compare our results with the expected decline in primary outcome indicators within an untreated nonproliferative diabetic retinopathy group during the same six - month period . \n nevertheless , the data are supportive of the need for a larger , randomized , placebo - controlled study that can verify any benefits of vitamin b in patients with nonproliferative diabetic retinopathy .", "role": "user" }, { "content": "backgroundthe purpose of this study was to determine whether a combination of vitamins b6 , b9 , and b12 is an effective intervention for reducing the signs and symptoms of nonproliferative diabetic retinopathy.methodsten subjects with type 2 diabetes mellitus ( n = 20 eyes ) with clinically diagnosed mild to moderate nonproliferative diabetic retinopathy were recruited from a private practice ophthalmology clinic for this open - label , uncontrolled , prospective six - month study . metanx vitamin tablets ( containing 3 mg l - methylfolate calcium , 35 mg pyridoxal-5-phosphate , and 2 mg methylcobalamin ) were administered at a dosage of two tablets daily . \n primary outcome indicators were the percent change in mean retinal sensitivity threshold measured by macular microperimetry and the percent change in mean central retinal thickness measured by spectral - domain optical coherence tomography.resultsthree subjects were lost to follow - up . in the remaining seven subjects , two of 14 eyes had foveal edema that prevented microperimetry measurements due to poor fixation . \n the remaining 12 eyes showed a nonlinear improvement in mean threshold retinal sensitivity ( p < 0.001 ) . \n overall change in mean central retinal thickness in 14 eyes was linear ( r2 = 0.625 ; p = 0.034 ) , with a significant reduction between one and six months ( p = 0.012).conclusionin this pilot study , the metanx intervention appeared to have some beneficial effects with respect to reducing retinal edema and increasing light sensitivity in subjects with nonproliferative diabetic retinopathy .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: we used data from a clinical research database of patients hospitalized at 97 acute - care hospitals in the u.s . \n that was compiled by carefusion ( department of clinical research , carefusion , marlborough , ma ) . \n the database includes extensive data in the following categories : clinical ( including diagnoses and vital signs ) ; laboratory ( e.g. , chemistry , hematology , and microbiology ) ; and administrative ( e.g. , demographics , admission source , length of hospitalization , and discharge status ) . \n eligible patients were those discharged from one of the designated hospitals between 1 january 2003 and 30 june 2007 with a principal diagnosis ( icd-9-cm ) of diabetes and a secondary diagnosis indicating skin or soft - tissue infection ( including cellulitis , infected ulcer , or surgical - site infection [ ssi ] ) that was culture documented within 48 h of admission . \n this study was approved by the new england institutional review board human subjects research committee ( wellesley , ma ) and was conducted in compliance with the health insurance portability and accountability act . \n we randomly split the study population into two groups : one for model derivation ( 75% of the population ) and the other for model validation ( the remaining 25% ) . \n candidate predictor variables used in the model were demographic data , a history of previous health care associated infection , clinical presentation , concomitant chronic disease(s ) , previous lea , and type of skin or soft - tissue infection ( cellulitis , ulcer or other infection , or ssi ) . \n our outcome measure of interest was lea during the index hospitalization , which was identified by icd-9 procedure codes ( 841.1 amputation , toe ; 841.2 amputation , foot ; 841.3 disarticulation , ankle ; 841.4 amputation , malleoli ; 841.5 amputation , knee , below nec [ not elsewhere classified ] ; 841.6 disarticulation , knee ; and 841.7 amputation , knee , above ) . using the derivation cohort \n , we conducted univariate analyses to determine the proportion of patients with each candidate predictor who underwent an lea . \n we then fit a stepwise multivariate logistic regression model to identify independent predictors of lea and to estimate their relative predictive weights ( coefficients ) . using previously published methods \n , we converted the coefficients for the independent predictors into a simplified risk score system ( 11 ) . \n specifically , we calculated the number of points assigned to each variable by dividing its regression coefficient by the smallest coefficient in the model then rounded this quotient to the nearest whole number . \n we then calculated each subject s lea risk score by summing up the points of all variables present on admission . \n we assessed model discrimination using the c - statistic , which defines how well a model or prediction rule can discriminate between patients who do and do not have an event and measures how well a clinical prediction rule correctly ranks patients in order by risk . \n we assessed model calibration using the hosmer - lemeshow goodness - of - fit test , which assesses whether the observed and expected event rates match in subgroups of the model population . \n the test specifically identifies subgroups as the deciles of fitted risk values , and models with similar expected and observed event rates ( i.e. , a large p value ) are considered to be well calibrated . \n we then used the cochran - armitage trending statistic , which modifies the test to incorporate a suspected ordering , to assess the ability of the risk score system to differentiate low - risk from high - risk patients in a graded response . \n all analyses were conducted using statistical analysis system ( version 9.01 ; sas institute , cary , nc ) . \n we randomly split the study population into two groups : one for model derivation ( 75% of the population ) and the other for model validation ( the remaining 25% ) . \n candidate predictor variables used in the model were demographic data , a history of previous health care associated infection , clinical presentation , concomitant chronic disease(s ) , previous lea , and type of skin or soft - tissue infection ( cellulitis , ulcer or other infection , or ssi ) . \n our outcome measure of interest was lea during the index hospitalization , which was identified by icd-9 procedure codes ( 841.1 amputation , toe ; 841.2 amputation , foot ; 841.3 disarticulation , ankle ; 841.4 amputation , malleoli ; 841.5 amputation , knee , below nec [ not elsewhere classified ] ; 841.6 disarticulation , knee ; and 841.7 amputation , knee , above ) . using the derivation cohort \n , we conducted univariate analyses to determine the proportion of patients with each candidate predictor who underwent an lea . \n we then fit a stepwise multivariate logistic regression model to identify independent predictors of lea and to estimate their relative predictive weights ( coefficients ) . using previously published methods \n , we converted the coefficients for the independent predictors into a simplified risk score system ( 11 ) . \n specifically , we calculated the number of points assigned to each variable by dividing its regression coefficient by the smallest coefficient in the model then rounded this quotient to the nearest whole number . \n we then calculated each subject s lea risk score by summing up the points of all variables present on admission . \n we assessed model discrimination using the c - statistic , which defines how well a model or prediction rule can discriminate between patients who do and do not have an event and measures how well a clinical prediction rule correctly ranks patients in order by risk . \n we assessed model calibration using the hosmer - lemeshow goodness - of - fit test , which assesses whether the observed and expected event rates match in subgroups of the model population . \n the test specifically identifies subgroups as the deciles of fitted risk values , and models with similar expected and observed event rates ( i.e. , a large p value ) are considered to be well calibrated . \n we then used the cochran - armitage trending statistic , which modifies the test to incorporate a suspected ordering , to assess the ability of the risk score system to differentiate low - risk from high - risk patients in a graded response . \n all analyses were conducted using statistical analysis system ( version 9.01 ; sas institute , cary , nc ) . \n among hospitalized patients , 3,018 met our inclusion criteria for a diabetic foot infection , with cellulitis ( in 80% ) and an infected ulcer ( 16% ) being the most common diagnoses . \n we used 2,230 patients for the derivation cohort and 788 for the validation cohort ; all baseline characteristics were similar between the two cohorts ( table 1 ) . \n a total of 646 ( 21.4% ) patients underwent an lea during their index hospitalization ; the number ( and rate ) in the derivation cohort was 463 ( 20.8% ) compared with 183 ( 23.2% ) for the validation cohort . \n for those patients undergoing an lea , the median time from admission to amputation was 4 days , with an interquartile range of 27 days . \n a previous lea of some type was noted in ~27% of patients in the derivation cohort and 26% in the validation cohort . \n characteristics for patients in the derivation and the validation cohorts data are n ( % ) , unless otherwise indicated . \n the p values for each variable is > 0.05 , indicating that the derivation and validation cohorts are similar . for the entire study cohort , \n the patients who underwent an lea were significantly older ( median age in years [ interquartile range ] 62 [ 5372 ] vs. 60 [ 5071 ] ; p < 0.0001 ) , and their in - hospital mortality rate was significantly higher ( 2.3 vs. 1.1% ; p < 0.05 ) compared with patients who did not require amputation . \n the most common finding on culture was a polymicrobial ( two or more different microorganisms ) infection , which accounted for ~57% of all patients . \n a detailed accounting of pathogen distribution is shown in supplementary appendix a. as shown in table 2 , in the derivation cohort the univariate analysis revealed that the following factors were significantly associated with lea ( p < 0.05 ) : older age ; male sex ; transfer from another hospital or nursing home ; previous lea ; coronary , renal , or peripheral vascular disease ; low serum albumin ; elevated values for white blood cell count , prothrombin time or international normalized ratio , or creatinine ; elevated body temperature ; the presence of a foot ulcer ; and the presence of an ssi . univariate analysis of risk factors associated with lea in the derivation cohort using stepwise regression analysis , we found 11 independent predictors of lea ( table 3 ) . \n the most highly significant ( p < 0.0001 ) were ssi , vasculopathy , previous lea , and white blood cell count > 11,000 per mm . \n the predictive model developed using these predictors had very good discrimination ( c - statistic 0.76 ) and excellent calibration between predicted and observed lea rates ( hosmer - lemeshow test showing that they did not significantly differ across risk deciles ; p = 0.63 ) ( fig . \n patients in the highest risk decile had a predicted probability of lea of 59.4% and an observed lea rate of 58.7% , whereas those in the lowest decile had a predicted probability of lea of 4% and an observed lea rate of 5% . \n the predictive model yielded a good calibration when applied to the validation cohort ( hosmer - lemeshow test ; p = 0.33 ) . \n * we used the method described by sullivan et al . ( 11 ) to calculate the risk score weight : step 1 : divide each regression coefficient by the smallest coefficient in the model ( in our model , this is chronic renal disease or creatinine > 3 mg / dl ) . \n step 2 : round this quotient to the nearest whole number . for example , to calculate the score weight of male sex , we divided its coefficient of 0.1988 by 0.1371 , resulting in a quotient of 1.44 . rounding this quotient to \n we then calculated each subject s overall lea risk score by summing the points of all variables present on admission . \n we retained these two variables for clinical plausibility despite the fact that they are not statistically significant at the 0.05 level in the model . \n comparison of the predicted probability of lea against the observed amputation rate for both derivation and validation cohorts , by decile . \n model hosmer - lemeshow goodness - of - fit test = 6.2 , p = 0.63 vs. = 9.2 , p = 0.33 for the derivation vs. the validation cohorts , indicating excellent fit of the model . for each patient \n , we summed all the variables present on admission to create an lea risk score . \n the use of a five - level risk strata allows easy application of risk stratification for comparisons of outcomes . \n lea rates in the derivation and validation cohorts increased significantly by risk score strata ( p < 0.0001 by the cochran - armitage trending test for both derivation and validation cohorts ) ( fig . \n the risk of lea for patients aged < 50 years and without any of the other 10 factors in the risk score system was essentially zero . \n in contrast , for those whose score was 21 , lea risk was ~50% . the findings in the validation cohort were similar to those in the derivation cohort . \n observed lea rates by risk score strata for both derivation and validation cohorts ( cochran - armitage trending test , p < 0.0001 ) . \n among hospitalized patients , 3,018 met our inclusion criteria for a diabetic foot infection , with cellulitis ( in 80% ) and an infected ulcer ( 16% ) being the most common diagnoses . \n we used 2,230 patients for the derivation cohort and 788 for the validation cohort ; all baseline characteristics were similar between the two cohorts ( table 1 ) . \n a total of 646 ( 21.4% ) patients underwent an lea during their index hospitalization ; the number ( and rate ) in the derivation cohort was 463 ( 20.8% ) compared with 183 ( 23.2% ) for the validation cohort . \n for those patients undergoing an lea , the median time from admission to amputation was 4 days , with an interquartile range of 27 days . \n a previous lea of some type was noted in ~27% of patients in the derivation cohort and 26% in the validation cohort . \n characteristics for patients in the derivation and the validation cohorts data are n ( % ) , unless otherwise indicated . \n the p values for each variable is > 0.05 , indicating that the derivation and validation cohorts are similar . for the entire study cohort , \n the patients who underwent an lea were significantly older ( median age in years [ interquartile range ] 62 [ 5372 ] vs. 60 [ 5071 ] ; p < 0.0001 ) , and their in - hospital mortality rate was significantly higher ( 2.3 vs. 1.1% ; p < 0.05 ) compared with patients who did not require amputation . \n the most common finding on culture was a polymicrobial ( two or more different microorganisms ) infection , which accounted for ~57% of all patients . \n as shown in table 2 , in the derivation cohort the univariate analysis revealed that the following factors were significantly associated with lea ( p < 0.05 ) : older age ; male sex ; transfer from another hospital or nursing home ; previous lea ; coronary , renal , or peripheral vascular disease ; low serum albumin ; elevated values for white blood cell count , prothrombin time or international normalized ratio , or creatinine ; elevated body temperature ; the presence of a foot ulcer ; and the presence of an ssi . univariate analysis of risk factors associated with lea in the derivation cohort \n using stepwise regression analysis , we found 11 independent predictors of lea ( table 3 ) . \n the most highly significant ( p < 0.0001 ) were ssi , vasculopathy , previous lea , and white blood cell count > 11,000 per mm . \n the predictive model developed using these predictors had very good discrimination ( c - statistic 0.76 ) and excellent calibration between predicted and observed lea rates ( hosmer - lemeshow test showing that they did not significantly differ across risk deciles ; p = 0.63 ) ( fig . \n patients in the highest risk decile had a predicted probability of lea of 59.4% and an observed lea rate of 58.7% , whereas those in the lowest decile had a predicted probability of lea of 4% and an observed lea rate of 5% . \n the predictive model yielded a good calibration when applied to the validation cohort ( hosmer - lemeshow test ; p = 0.33 ) . \n * we used the method described by sullivan et al . ( 11 ) to calculate the risk score weight : step 1 : divide each regression coefficient by the smallest coefficient in the model ( in our model , this is chronic renal disease or creatinine > 3 mg / dl ) . \n step 2 : round this quotient to the nearest whole number . for example , to calculate the score weight of male sex , we divided its coefficient of 0.1988 by 0.1371 , resulting in a quotient of 1.44 . rounding this quotient to \n we then calculated each subject s overall lea risk score by summing the points of all variables present on admission . \n we retained these two variables for clinical plausibility despite the fact that they are not statistically significant at the 0.05 level in the model . \n comparison of the predicted probability of lea against the observed amputation rate for both derivation and validation cohorts , by decile . \n model hosmer - lemeshow goodness - of - fit test = 6.2 , p = 0.63 vs. = 9.2 , p = 0.33 for the derivation vs. the validation cohorts , indicating excellent fit of the model . \n for each patient , we summed all the variables present on admission to create an lea risk score . \n the use of a five - level risk strata allows easy application of risk stratification for comparisons of outcomes . \n lea rates in the derivation and validation cohorts increased significantly by risk score strata ( p < 0.0001 by the cochran - armitage trending test for both derivation and validation cohorts ) ( fig . \n the risk of lea for patients aged < 50 years and without any of the other 10 factors in the risk score system was essentially zero . \n observed lea rates by risk score strata for both derivation and validation cohorts ( cochran - armitage trending test , p < 0.0001 ) . \n in this large cohort of patients hospitalized for a diabetic foot infection , more than one - fifth required an lea . in reviewing numerous clinical and laboratory variables present at hospital admission in our derivation cohort \n , we identified 11 significant independent risk factors for lea . by rounding the logistic regression coefficients into integers \n , we developed a simple lea risk score system with five strata that we demonstrated was highly predictive of the risk for lea . using the patients in the validation cohort \n , we were then able to demonstrate that this risk score was indeed valid and well calibrated . \n most of the factors included in our risk score have been reported as risks for lea in smaller , previously published studies ( 7,12,13 ) . \n most patients with diabetic foot ulcers do not have a fever or leukocytosis ( 14 ) , which define a severe infection according to the infectious diseases society of america and the international working group on the diabetic foot criteria . \n these severe diabetic foot infections are associated with a greater risk of lea than those of mild or moderate severity . \n previous studies ( 15,17 ) also have identified renal insufficiency as being associated with an increased risk of amputations . \n other studies have identified increasing age ( 18 ) , male sex ( 16 ) , and hypoalbuminemia ( 19 ) as risks for lea . \n likewise , a previous lea is a strong risk factor predicting the need for another amputation ( 12 ) . in none of these previous studies , \n however , did the authors attempt to construct a scoring system to predict amputation risk for both men and women . in a previous study ( 20 ) \n , we showed that patients with ssis who were transferred from another acute - care facility had worse clinical and economic outcomes , perhaps because patients with infections of greater severity are more likely to be transferred to hospitals with more intensive resources or greater expertise . a recent meta - analysis ( 21 ) demonstrated a direct association between hyperglycemia ( as measured by hemoglobin a1c ) and lea . \n unfortunately , we did not have hemoglobin a1c values on most of our patients , but we did note a nonsignificant trend toward higher amputation rates in those with increased blood glucose levels on admission . \n all of our patients had an infection ; therefore , that variable was not among those included in our scoring system . \n it is noteworthy that the type of infection was associated with amputation risk , with ssis at the highest risk , followed by infected ulcers , when compared with cellulitis . \n our assumption is that these ssis may be associated with failed lower - extremity bypass procedures . \n we found no other studies that investigated the risk of adverse outcomes in patients with an infected ulcer compared with cellulitis or ssis . \n we did find other studies ( 7,14,22,23 ) that reported that deep infections ( especially those involving bone ) and necrotizing infections more often resulted in amputations . \n in particular , a patient with a low score may need fewer medical resources than a patient with a high lea risk score . at the other extreme , to try to avoid the tragedy of amputation , health care providers should concentrate efforts on a patient with a risk score of > 21 , who has a 50% chance of an lea . \n our finding that patients transferred from another acute - care hospital had the highest odds ratio for lea highlights the need of risk adjustment to appropriately evaluate outcomes for hospitals treating the most severe patients . because lea rates are sometimes used to compare quality of care for patients with diabetic foot complications , our risk adjustment score could be used to ensure that centers treating higher - risk patients are not unfairly penalized . \n furthermore , although this has not been tested , the score might be helpful to clinicians in deciding which patients with diabetic foot infections may need to be hospitalized . the lea risk score system has the benefit of being simple to use ; each of the risk factors is readily available , usually at the time of admission or soon afterward . \n our study is limited by the fact that our analysis was retrospective , and , although fairly inclusive , we could have missed potentially significant factors . for example , the individual reasons for amputation and whether amputation was elective or urgent were not captured in the database . \n one major risk factor that we did not capture that could have an effect on our risk score is a history of a previous lower - extremity revascularization procedure , which was a significant factor in other reports ( 24,25 ) . \n selection bias is another potential limitation when using administrative data to identify patients with skin or soft - tissue infections . to minimize potential bias related to the use of icd-9 coding , we limited our study to culture - confirmed infections . in conclusion \n , we used a large clinical database to develop and validate a risk score that seems to accurately stratify lea risk among patients hospitalized for a diabetic foot infection . \n we would like to see our risk score validated prospectively , including in patients treated on an outpatient basis . \n ", "role": "user" }, { "content": "objectivediabetic foot infection is the predominant predisposing factor to nontraumatic lower - extremity amputation ( lea ) , but few studies have investigated which specific risk factors are most associated with lea . \n we sought to develop and validate a risk score to aid in the early identification of patients hospitalized for diabetic foot infection who are at highest risk of lea.research design and methodsusing a large , clinical research database ( carefusion ) , we identified patients hospitalized at 97 hospitals in the u.s . between 2003 and 2007 for culture - documented diabetic foot infection . \n candidate risk factors for lea included demographic data , clinical presentation , chronic diseases , and recent previous hospitalization . \n we fit a logistic regression model using 75% of the population and converted the model coefficients to a numeric risk score . \n we then validated the score using the remaining 25% of patients.resultsamong 3,018 eligible patients , 21.4% underwent an lea . \n the risk factors most highly associated with lea ( p < \n 0.0001 ) were surgical site infection , vasculopathy , previous lea , and a white blood cell count > 11,000 per mm3 . \n the model showed good discrimination ( c - statistic 0.76 ) and excellent calibration ( hosmer - lemeshow , p = 0.63 ) . \n the risk score stratified patients into five groups , demonstrating a graded relation to lea risk ( p < 0.0001 ) . the lea rates ( derivation and validation cohorts ) were 0% for patients with a score of 0 and ~50% for those with a score of 21.conclusionsusing a large , hospitalized population , we developed and validated a risk score that seems to accurately stratify the risk of lea among patients hospitalized for a diabetic foot infection . \n this score may help to identify high - risk patients upon admission .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: although there have been advancements in the treatment of diabetes in recent years , diabetic retinopathy ( dr ) remains the most common cause of blindness among adults . according to the wisconsin epidemiologic study of diabetic retinopathy ( wesdr ) , 3.6% of type 1 diabetes patients and 1.6% of type 2 \n diabetes patients were legally blind.1 the time of disease onset is evident in type 1 diabetes patients , therefore we know with certainty that the development of dr is unusual before the fifth year of disease onset and reaches a prevalence of more than 95% 15 years after disease onset . on the contrary , up to 20% of type 2 diabetes mellitus patients , in whom the exact time of onset of the disease \n is less evident , may have signs of retinopathy at the time of diagnosis , which in most cases is preceded by a long unrecognized latency period . \n the prevalence of dr 15 years after disease onset in type 2 diabetes mellitus patients may reach 60%.2 the uk prospective diabetes study ( ukpds ) , a 10-year study of newly diagnosed type 2 diabetes patients , indicates that the presence of even a single aneurysm in these patients is evidence of dr , with the prevalence of this condition at diagnosis being 38%.2 although the percentage is higher among type 1 diabetes patients , the much greater absolute number of type 2 diabetes patients with this disease indicates dr to be a devastating complication in this category.3 however , the prevalence of progressive sight - threatening retinopathy is limited to 10%,4 which is still relatively high . \n the prevalence of dr of any severity in the diabetic population as a whole is approximately 30%.5 furthermore , we can not accurately predict when severe dr will progress to blindness , although hyperglycemia and hypertension are risk factors . \n the actual prevalence of blindness is approximately 5% ( range 3%7% ) and may be as high as 8%.4 although there are no comparative studies , it is highly probable that the incidence of diabetes mellitus in all its forms may vary according to the local resources and standards of care . \n there is abundant literature demonstrating that screening programs have been highly effective in reducing the incidence and the progression of dr.6 \n diabetic retinopathy tends to follow a progressive course from minor lesions to the most serious sight - threatening patterns , but there is frequently considerable overlapping . \n the earliest manifestations are mild and characterized by increased vascular permeability , followed by moderate to severe changes with intravascular clotting , defined as nonproliferative dr . \n a more advanced phase is the proliferation of new vessels , defined as proliferative dr ( pdr ) , with impending risk of hemorrhage . \n an ominous manifestation is significant macular edema ( clinically significant diabetic macular edema [ csdme ] ) caused by retinal thickening due to leaky blood vessels , which should be distinguished from mild thickness of the retina that does not have the same serious prognosis . \n the earliest changes are a loss of retinal neurons ( neurodegeneration ) and disruption of the vascular structure , which is essential to the survival of the retina.7 interruption of the integrity of retinal capillary bed , which allows the exchange of nutrients with the retina , leads to protein leakage and the appearance of exudates , which are among the early signs of dr . \n it is highly probable that the hyperglycemia in diabetes leads to an array of metabolic changes , many of which may be directed toward limitation or repair of the damage . \n all the above factors and possibly some other unknown factors interact to cause dr , and it is not known yet which factor may be the primary cause . \n the most well known structural components of retinal capillaries are the basement membrane and pericytes , which are cells that have both structural and regulatory functions.8 the disarrangement of these structures leads to weakening of the capillaries , aneurism , and protein leakage . \n loss of retinal pericytes is an early feature of dr and correlates with microaneurysm.9 other common features of early dr are the thickening of the capillary basement membrane and the increased deposition of extracellular matrix components , leading to the development of abnormal retinal hemodynamics . \n 10 a subsequent intervention of blood cells that clog the capillaries and lead to occlusion is probably the body s misguided attempt at damage limitation.11 there is extensive clot formation in the capillaries as the disease progresses , which interrupts blood flow and causes ischemia . in more advanced stages , there is an inordinate proliferation of blood vessels in an attempt to restore oxygen and nutrient supply to the ischemic territory . \n pathogenesis of pdr is essentially due to ischemia , and pathogenesis of csdme is due to the fluid leakage from retinal blood vessels into the area of the macula , which is rich in cones that are critical for color and daytime vision . \n this study mainly reviews prevention in the initial stages of the disease when medical intervention may be effective . \n proliferation may be mediated by vascular endothelial growth factor ( vegf ) , which will be discussed later . \n the etiology of dr is complex and predisposing factors are as follows : 1 ) duration of diabetes,12 2 ) poor glucose control,13 3 ) hypertension,14,15 4 ) pregnancy,16,17 5 ) puberty,18 6 ) renal disease19 ( the relation between kidney and retina is so relevant that the diagnosis of diabetic nephropathy should always be questioned in the absence of a dr ) , and 7 ) hyper - lipidemia20 ( believed to play a role in this complication , although this hypothesis has not been confirmed).21 these factors will be discussed in detail . \n the pathogenesis of dr includes both systemic and local factors , but we still do not know the exact influence of and role played by each in the different stages of the disease . \n the duration of diabetes is probably the strongest predictor of progression to dr,6 but is not clinically helpful in most cases of type 2 diabetes because diagnosis is delayed and the time of onset of the disease is unknown . \n the wesdr showed that incidence of retinopathy increased progressively from 8% 5 years after disease onset to 80% after 15 years.22 the recognition of the role of disease duration is one more argument in favor of those interventions that may delay the onset of diabetes . \n the role of hyperglycemia was proven by two landmark studies . the diabetes control and complications trial ( dcct ) , \n a study of 1441 type 1 diabetes patients randomly assigned to intensive and conventional treatment groups with different glycosylated hemoglobin ( hba1c ) levels , conclusively demonstrated that good control plays a critical role in the prevention of dr . in the intensively treated group \n the patients were assigned to a primary prevention group ( those with no signs of retinopathy ) and a secondary prevention group ( those with retinopathy ) according to the status of their retina . \n those in the primary prevention cohort had a similar cumulative incidence of retinopathy progression in the conventional and intensive arms untill 36 months , and then intensive treatment reduced the risk of retinopathy by 76% . \n the intensive group in the secondary intervention cohort fared worse than the nonintensive group during the first 18 months ; a phenomenon largely offset by a much greater long - term improvement with a reduced risk of 54% by 36 months.13 the results of the epidemiology of diabetes interventions and complications study , a follow - up study to the dcct , are interesting from a theoretical perspective because there was no further attempt to use intensive treatment and the hba1c levels of the two groups were nearly the same . \n even after 5 years , outcome of the intensive therapy was favorable.23 this phenomenon is termed a \n legacy effect. the data were deemed so relevant that , subsequently , the level of fasting blood glucose at which retinopathy appeared was included in the current criteria for the diagnosis of diabetes mellitus . in a recent study on the association of glycated hba1c and fasting plasma glucose ( fpg ) with the diagnosis of diabetes mellitus \n , the authors found that the highest increase in the prevalence of retinopathy occurs among individuals with hba1c 5.5 and fpg 5.8 mmol / l , and that , based on the areas under the receiver operating characteristic curves , hba1c was found to be a strong discriminator of retinopathy.24 with a protocol similar to that of the dcct , the ukpds randomly assigned 3867 newly diagnosed type 2 diabetes patients to an intensive or conventional treatment group and found a statistically significant 25% reduction in microvascular complications including the need for photocoagulation of the retina . \n this is a much more crude result than in the dcct because the impact on each complication was not clearly determined and favored lowering blood glucose levels . \n an epidemiological analysis of the ukpds data demonstrated the existence of a continuous relationship between the risk of microvascular complications and blood glucose level ; for each percentage point decrease in hba1c , the relative risk of microvascular complication was reduced by 35%.25 a follow - up of the ukpds subjects , analogous to that of the dcct , demonstrated the existence of the legacy effect , with a 24% reduction in the risk of microvascular complications.26 the veterans affairs diabetes trial ( vadt ) that followed a different population of 1791 older diabetic veterans , mostly men , for a median of 5.6 years did not find any effect from intensive glucose control on retinopathy ( progression to proliferative disease , macular edema , increase in severity of disease , and new onset of disease ; all p = not specified [ ns]).27 similar results were obtained for the advance ( action in diabetes and vascular disease : preterax and diamicron mr controlled evaluation ) study in which there were no changes in the rate of severe retinopathy.28 taken together , these observations suggest that the effect of good glycemic control is most evident at disease onset when harmful microvascular complications can set in . any later intervention is likely to have only modest beneficial effect . \n this is confirmed by the ukpds observation that a favorable legacy effect of glucose control was found in newly diagnosed subjects which lasted until follow - up.26 however , the vadt and advance studies in a longstanding diabetic population did not find any significant effect . \n the exact mechanisms that cause persistent hyperglycemia to become dr are still partially unknown , however , the polyol pathway has been found to play a prominent role.28 the polyol pathway is dependent on the glucose overload to the noninsulin - dependent cells such as cells of the eye.29 this pathway leads to the intracellular accumulation of sorbitol and fructose.30 it has been demonstrated that the increase in aldose reductase activity within the retinal cells contributes to oxidative stress and overexpression of vegf protein.31 furthermore , an increased frequency of the z-2 allele of the aldose reductase gene in diabetes patients with dr vs those without dr ( 39.1% vs 26.5% ; = 6.9 ) has been demonstrated , which partially explains the role of genetics in this complication.31,32 modest results were obtained in therapeutic trials with aldose reductase inhibitors that reduce the efficiency of the polyol pathway , and one of these substances purported to be beneficial for diabetic neuropathy has now been withdrawn from the market for proven negative cost - to - benefit ratio.33,34 furthermore , these drugs have frequent and potential dangerous side effects ( liver and kidney damage ) . increased oxidative stress causes a characteristic endothelial dysfunction , which has been observed in diabetes patients and normal subjects.35,36 brownlee and colleagues demonstrated that damage can be reversed by suppression of intracellular free radicals with manganese superoxide dismutase , which has an antioxidant effect.37 another important and still not totally explored aspect is that oxygen - free radicals can activate nuclear factor b and in turn many genes related to vascular stress response.38 one disappointing aspect is that clinical trials with vitamin e , a potent antioxidant , failed to demonstrate beneficial effects.39 this failure could be explained by the fact that since vitamin e only acts by scavenging already formed oxidants in this antioxidant therapy , this therapy may be a more symptomatic rather than causal treatment for vascular oxidative stress.40 the formation of advanced glycation end products ( ages ) may also have a role . \n these compounds result from the nonenzymatic binding of glucose to protein side chains.41 accumulation of these protein side chains in the capillaries of the retina leads to loss of pericytes , causing blood \n retinal barrier dysfunction , increasing synthesis of vegf in the retina,42 and increasing monocyte adhesion to the retinal endothelial cells through an increase in the expression of intercellular adhesion molecule 1.43 aminoguanidine , an inhibitor of age formation , appears to reduce the early histological changes in the retina . \n however , the drug causes anemia in humans.44 another mechanism of damage is the activation of the protein kinase c ( pkc ) family pathway.45 this pathway is a consequence of hyperglycemia and has a role in the pathogenesis of dr.46 the main isoform implicated is pkc-2 , which causes hyperexpression of endothelin , increased vascular permeability , alterations in renal blood flow , and in vitro stimulations of vegf secretion.47 two drugs with inhibitory effect have been developed , ruboxistaurin ( eli lilly , indianapolis , in ) and midostaurin , but their effectiveness is still uncertain.48 brownlee recently put forth a unifying theory according to which glucose overload flowing through the glycolytic pathway could cause a kind of collateral damage consisting of superoxide production in endothelial cells at the mitochondrial level . \n the superoxide could cause dna damage in turn , and the consequent attempt to repair the damage could start the aforementioned dangerous cascades involved in diabetes complications.49 the existence of all these pathways leading to diabetic complications led to the search for antioxidant compounds that are still in the pipeline or in early experimental stages . among the available compounds , \n lipoic acid is purported to have the ability to restore endothelial function in diabetes.50 as will be dealt with later , other commonly used drugs such as thiazolidinediones , statins , angiotensin - converting enzyme inhibitors ( acei ) , and angiotensin type 1 ( at1 ) receptor blockers may also have potent antioxidant effects , although there are no evident conclusive results for the protection of the retina . \n an increase in vegf , a family of proteins mitogenic for vascular endothelial cells that increase vascular permeability , has been demonstrated in dr.51 the knowledge of the role of these substances led to extensive research on its antagonists . \n the systemic administration of these antagonists might cause serious damage by blocking angiogenesis , impairing the response to ischemic events , worsening peripheral ischemia , increasing proteinuria , and impairing wound healing process,52 and hence the use of these agents is restricted to intravitreal administration . \n however , a backflow is possible from the vitreal chamber to the systemic circulation.53 it has yet to be proven that these agents for intravitreal administration are preferred over triamcinolone acetonide . \n other growth factors of interest are growth hormone ( gh ) and insulin - like growth factor-1 ( igf-1 ) . \n hypophysectomy was performed in advanced dr in the past,54 with a good rate of regression . \n further evidence for the role of gh or igf - i comes from the observation of the increased rate of appearance and progression of the dr in puberty and pregnancy , which are stages of increased gh secretion.55 the gh antagonist , pegvisomant , has been used to induce regression of neovascularization , with a negative outcome.56 octreotide , a somatostatin analog , decreases the need for photocoagulation.57 although the literature on the pathogenetic mechanisms that lead to dr is abundant , exploiting the mechanisms did not yield fruitful results . \n control of hyperglycemia proved to be the mainstay of prevention of dr and progression of the disease was able to be reversed to a certain point . in the intensive treatment of diabetes \n , the physicians should make any effort to avoid the risk of hypoglycemia as it is a risk factor for progression to dr . \n the action to control cardiovascular risk in diabetes ( accord ) eye study,58 a subset of the accord trial , was designed primarily to study the effects of intensive glycemic control on cardiovascular events in type 2 diabetes subjects . \n the primary outcome of 2,856 subjects was a 3-step change on a 17-step retinopathy scale ( from retinal photographs ) or development of pdr . \n after 4 years of follow - up , intensive treatment to lower the blood glucose to normal levels significantly reduced the incidence of progressive dr compared with conventional treatment that resulted in a higher hba1c levels ( 7.3% vs 10.2% ) , but not vision loss ( 16.3% vs 16.7% ) . \n however , the drawbacks of this study were the excess mortality and the absence of positive effects on adverse cardiovascular events in the intensive arm . \n although the exact cause of the increased mortality is not known , there is general agreement that the intensive intervention to reduce the blood glucose level should be individually weighed against the risk . \n we observed an unexpected improvement in the most initial forms of retinopathy while using a combination of arginine , glutamine , and hydroxy--butyrate coupled with an increased percentage of dietary protein for the treatment of diabetic foot ulcers over 14 months . \n the treated patients presented a reduction in the number of microaneurysms after 6 months ( 20% ; p = 0.012 ) and 12 months ( 39% ; p = 0.006 ) , and retinal exudates were reduced 38.6% ( p = 0.000 ) at 6 months and 52% at 12 months ( p = 0.003 ) . \n we hypothesize that protein loss in diabetes patients through neoglycogenesis and proteinuria may cause a disarrangement of the basement membrane of the retinal capillaries , a phenomenon that was reversed by diet and the combination of drugs . \n there is sufficient data to validate high blood pressure as a risk factor for dr and the positive effect of blood pressure reduction on the progression of the disease.59 the ukpds showed that intensive blood pressure control in type 2 diabetes was effective in reducing the microvascular complication associated with diabetes . \n analogous to the results of blood glucose control , the initial study results released in 1997 demonstrated that an effective blood pressure control could induce a relative risk reduction of 37%.60 however , contrary to the blood glucose results , there was no legacy effect for blood pressure and the ukpds follow - up study in 2007 , 10 years after the intensive treatment had been interrupted , reported only 16% relative risk reduction in the intensive group ( p = ns ) . \n thus , it appears that good blood pressure control must be continued to control disease progression.61 the accord eye study group published the results of the effects at 4 years of either intensive or standard treatment for diabetes and dyslipidemia or for systolic blood pressure control on 2856 diabetes subjects.58 in 4 years , the rate of progression was 10.4% with intensive blood pressure lowering treatment vs 8.8% with standard therapy ( p = ns ) . \n according to the authors , intensive glycemic control and intensive combination treatment of dyslipidemia , but not intensive pressure control , reduced the rate of progression of dr . \n there have been many studies on acei and angiotensin receptor blockers ( arbs ) to investigate the existence of direct effects not mediated by blood pressure reduction . \n angiotensin system in the eye62 and the in vitro binding of angiotensin ii to the at1 receptors , which causes a series of negative effects such as inflammation , oxidative stress , neoangiogenesis , and fibrosis.63 however , the in vivo studies did not confirm these observations completely . \n the ukpds did not find any significant differences among patients treated with atenolol , a beta blocker , and those treated with captopril , an acei . \n the euclid study did not consider dr as a primary end - point and demonstrated that normoalbuminuric and microalbuminuric lisinopril could significantly reduce the progression of dr in normotensive diabetes patients but with no decrease in incidence.63 however , in this study , statistical significance almost disappeared after adjusting for the mean hba1c of the control group . \n thus , this study can be considered only suggestive and not conclusive . in another highly sophisticated study , the direct protect , in which both type 1 and 2 diabetes patients were studied for prevention and progression of dr with the arb candesartan , \n the only clearly significant outcome not specified as a primary end - point was a 34% regression ( p = 0.009 ) mostly in subjects with mild disease.64 overall , one can surmise that the benefits attributable to the current acei / arb blockers are marginal or absent . \n the current recommendations for control of blood glucose and hypertension are hba1c < 7% ( < 6.5% according to the european association for the study of diabetes ) and blood pressure 130/80 mm hg.65 \n among the known risk factors , hyperlipidemia is associated with the presence of hard exudates in the retina,66 which has been confirmed by recent studies . \n nathan and colleagus found a significant association of total to high - density lipoprotein ( hdl ) cholesterol ratio and triglycerides only on significant macular edema and hard exudates , which in itself is not proof of cause effect.67 the fenofibrate intervention and event lowering in diabetes study was designed to answer these questions . \n fenofibrate is a peroxisome proliferator receptor ( ppr)- agonist that lowers triglycerides , reduces total and low - density lipoprotein ( ldl ) cholesterol , increases hdl cholesterol , and decreases small ldl particles and apolipo - protein b.67 fenofibrate reduced the need for laser treatment and less consistently the progression of retinopathy.68 the effects of fenofibrate are independent of lipid levels , as demonstrated by the observation that ppr- may reduce the expression of vegf receptor 2.69 although the aim of this review is limited to the pharmacological treatment of dr , it is worth mentioning that most of the effective treatments of dr now involve surgical or laser procedures . \n the correct therapeutic approach to dr can be summarized as follows : blood glucose control ; fundus examination ( ophthalmoscopy , retinal fluoroangiography , indocyanine green angiography , and optical coherence tomography ) ; evaluation of the stage of progression if any ; retinal laser therapy to prevent the proliferation of neovessels ; or surgical therapy in growth of neovessels into the vitreous , in vitreous hemorrhage , or in fibrous tissue proliferation on the retinal surface or on the optical disc . in these cases , \n vitrectomy is the only methodology available to interrupt the progression of the disease , through the suction of hematic vitreous , that , if left untreated , is an obstacle to vision and supports the growth of neovessels . \n furthermore , the intravitreal injection of anti - vegf drugs ( ranibizumab , pegaptanib , bevacizumab , etc ) improved the prognosis of retinal neovessels and exudative disorders . \n all these observations are complicated because dr is probably not a single disease , and the dependency on different causative factors may vary according to the different stages of the disease . \n clinicians may be disappointed by divergent and often conflicting study results if the studies do not consider this aspect of the disease . \n one example is the use of rosiglitazone , suspected of causing macular edema under certain circumstances,69 although we did not find any effect in a retrospective series.70 \n current medical interventions may be useful if carried out early , and the effect is limited to the rate of appearance and the minor manifestations of the disease . when the disease progresses , the best treatment option is laser therapy or surgery , and is not the recommended medical treatment at present .", "role": "user" }, { "content": "there has been a considerable advancement in the treatment of diabetes and understanding of the biochemical mechanisms underlying diabetic complications in the last 20 years . \n however , this advancement has not translated into a consistent reduction in diabetic retinopathy , one of the most frightening complications of diabetes mellitus . \n it is probable that greater attention to preventive intervention will help reduce the damage load in the next future , and that several drugs for the treatment of more advanced stages of diabetic retinopathy will become available . \n competent strategies targeting prevention based on screening programs should be proposed to reduce the burden and to improve the clinical outcome of this devastating diabetes complication .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: spontaneous cerebral arterial dissections ( cad ) are more frequent among young patients ( 40 - 45 years of age [ 1 , 2 ] ) , of which the internal carotid artery ( ica ) are one of the major sites for dissections . \n spontaneous cads are generally related to : connective tissue diseases [ fibromuscular dysplasia in up to 15 - 50% of bilateral internal carotid artery dissection ( bicad ) , ehlers - danlos syndrome , marfan syndrome , polycystic kidney disease , osteogenesis imperfecta , and systemic lupus erythematosus ] and/or preceding infectious diseases . \n internal carotid artery dissections ( icads ) may account for up to 2.5% of all first strokes and are responsible for 5 - 20% [ 4 , 6 ] of all ischemic strokes ( the commoner type among young patients ) in adults . among all icad , bicad is as frequent as 5 - 21% despite possible initial presentation with unilateral symptoms [ 7 , 8 , 9 ] . \n icad without subarachnoid hemorrhage ( sah ) are more frequent in younger patients ( < 30 years of age ) , while vertebro - basilar dissections with sah are more common in older patients ( > 30 years of age ) . \n common presenting features of spontaneous icad include : headache , ipsilateral neck pain , incomplete horner 's syndrome ( ptosis and myosis ) , bruits , transient ischemic attack / cerebrovascular accident signs as amaurosis fugax , syncope , encephalopathy and focal signs . these might be explained by either embolic event and/or reduced flow distal to the dissected segment and/or concurrent sah . \n most cases can be diagnosed by mri , mra , and cta ; however , angiography is still needed for some cases . \n treatment consists of anticoagulation / antiplatelet therapy , while endovascular or surgical interventions generally are indicated for intradural cases with sah or when persisting clinical deterioration is noted despite anticoagulation . \n a case of simultaneous spontaneous acute bicad concomitant with inadequate collateral blood supply from the circle of willis , preceded by isolated rigorous cough in a patient without any risk factor or infectious disease was not reported previously and is hereby presented , emphasizing the therapeutic implication of these concomitant findings . \n a 45-year - old man who suffered from paroxysmal severe nonproductive cough lasting for 5 days before his admission was referred to our emergency room from another hospital . family and personal history were noncontributory . by the fifth day \n a bicad with severe stenosis was demonstrated on cta . a tiny anterior communicating artery ( acom ) with no bilateral posterior communicating artery ( pcom ) \n , immediate administration of heparin was initiated . on his arrival to our emergency room , \n the patient 's neurological findings consisted of dysarthria , left hemiparesis ( hand pronation ) and bilateral babinski signs . \n his blood tests were normal except for prolonged ptt ( > 120 s ) due to previous heparin administration . \n the patient was transferred to the neurointensive care unit for the continuation of heparin treatment , maintaining a ptt range of 60 - 70 s with concomitant rigorous regulation of blood pressure ( systolic 110 - 140 mm hg ) . persisting clinical deterioration for the next following hours despite anticoagulation was noted : the patient developed neglect and became hemiplegic . \n he was taken to the angiography room : under general anesthesia four vessels angiography was performed demonstrating near complete occlusion of the right ica and severe stenosis of the left ica due to bicad in the cervical area ( fig . \n stenting of both ica ( two stents each side ) was performed restoring flow bilaterally with normal parenchymal blush ( fig . \n 3 ) . a small acom with mild flow from left to right was demonstrated , while restoring the flow in the left hemisphere . \n following stenting , the patient received iib / iiia - antagonist further converted to clopidogrel and aspirin by the next day , and heparin treatment was discontinued . \n two days following stenting , a subcortical small watershade infarct was demonstrated on a ct ( in the para - midline aca - mca passage ) further supporting that hypoperfusion was the underlying cause ( fig . \n a thorough workup for venous - arterial and connective tissue diseases , both personal and familial , was noncontributory . \n gradual improvement was noted and the patient was discharged after 10 days , showing further improvement : fully conscious , able to stand and walk with some support , less prominent neglect and dysarthria . \n he was referred to further rehabilitation and resumed normal activity as a physician by 3 months . \n antiplatelet ( aspirin and plavix for 6 months ) and neuroimaging were prescribed on discharge . \n the patient did not show any new neurological event until now , a year from treatment . \n icad can account for 10 - 25% of strokes in young patients [ 2 , 8 , 10 , 11 , 12 ] and is considered as one of the main causes for stroke recurrence . among 1 - 5% of all spontaneous icad cases , a heritable connective - tissue disorder can by identifiable and 5% may have one family member with spontaneous dissection of various arteries including the aorta or its main branches [ 13 , 14 , 15 , 16 ] . \n reported a case of a previously healthy 29-year - old woman with bilateral vertebral artery dissection ( vad ) and icad associated with multiple aneurysms ( saccular and fusiform ) that resolved spontaneously by 6 months . \n the natural course of icad seems to be composed of an acute phase during which conservative or more rarely endovascular / surgical treatments are undertaken followed by a chronic phase during which a recanalization occurs in the majority of patients during the following 6 months . \n some have reported that delayed recanalization can occur after 16 months as well , a fact that might prompt individual consideration regarding the time for anticoagulation / antiplatelet therapy . \n recently , schwartz et al . reported that among 177 young patients , 8.5% had recurrent ischemic events unrelated to the type of antithrombotic agent ( others have reported a recurrence of 15% ) and 1.1% had recurrent dissections ( others have reported a recurrence of 3 - 8% after longer clinical follow - up of up to 7.4 years [ 21 , 22 , 23 ] ) . \n reported a case of an adult male with cad and massive right hemisphere infarct during the course of pertussis . \n this patient as ours had no predisposing risk factors ( htn , dm , dyslipidemias , connective tissue diseases or smoking ) . \n their patient required 6 weeks of acute care hospitalization during which craniectomy and temporal lobe resection were needed followed by prolonged rehabilitation . \n preceding respiratory tract infection has been proposed as a possible risk factor for icad supported by the fact that the occurrence of icad peaks during the fall [ 24 , 25 , 26 ] . \n [ 24 , 25 ] reported that patients with cad had a higher prevalence of infections compared with controls ( 62 vs. 22% ) , while excluding mechanical factors as cough , sneezing and vomiting . mechanical cough ( naming , unrelated to infectious diseases ) causing dissections is reported in just few case studies describing vad rather than cad . \n reported a case of a 45-year - old man who developed wallenberg 's syndrome due to vad following severe cough . \n herr et al . reported a case of a man with vad presenting with signs of posterior - inferior cerebellar artery territory stroke , following severe cough . \n we hereby describe a unique case of a patient with rigorous noninfectious cough followed by acute bilateral spontaneous dissection of the anterior rather than posterior circulation and with concomitant inadequate collaterals from the circle of willis . \n it is generally accepted that most of the icad cases proceed to recanalization within 6 months after dissection . \n progression of disease is believed to start a few days post - dissection and can take up to 6 months . \n the treatment for icad consists of three possible approaches [ 29 , 30 ] : conservative , endovascular or surgical . \n conservative treatment consists of two steps : an acute anticoagulation with heparin followed by secondary prophylaxis by oral anticoagulation / antiplatelet that normally is sufficient for 3 - 12 months ( however , delayed recanalization as described by vicenzini et al \n . can prolong this period ) . although anticoagulation is recommended , the question whether warfarin or aspirin is more effective for recanalization is yet debatable . \n once recanalization is documented and arterial flow is reestablished , anticoagulation continuation should be reconsidered . \n the patient must therefore undergo neuroimaging follow - up ( mra and mri ) during the following 3 - 6 months and avoid forceful efforts . \n surgical and/or endovascular treatments are indicated for spontaneous icad with either persisting severe stenosis ( mainly for intradural icad ) , progressive neurologic symptoms despite conservative treatment ( as in our patient ) or bicad that result in severe cerebral hemodynamic impairment . \n patients with icad and sah require either surgery or endovascular treatment due to recurrence tendency . \n to our knowledge , this represents the first reported case of spontaneous bicad following isolated rigorous cough with inadequate circle of willis that seemed to have important therapeutic implications . \n bicad with concomitant inadequate circle of willis ( tiny acom with no pcom as in our patient ) can prone for hypoperfusion which might not respond to conservative treatment and can lead to rapid deterioration and therefore prompt to earlier endovascular intervention as was done in this case . \n rigorous cough can solely cause acute spontaneous bicad that should be suspected even in a patient with no other risk factors as in our patient . \n we would therefore recommend a thorough evaluation of the collateral flow in patients with uni-/bilateral icad , which might facilitate the decision in whom to perform an early arterial flow reestablishment .", "role": "user" }, { "content": "background and purposeemphasizing the therapeutic and diagnostic implications of concomitant inadequate collaterals from the circle of willis in a rare case of spontaneous acute bilateral internal carotid artery dissection ( bicad ) following 5 days of isolated rigorous cough ( pertussis like).case descriptiona 45-year - old male has been referred to our department with rapid neurological deterioration consisting of dysarthria and severe left hemiparesis following 5 days of isolated rigorous cough . \n cta demonstrated bicad , a tiny anterior communicating artery and no bilateral posterior communicating artery . \n the patient had no personal or familial risk factors . infectious , traumatic , vascular and connective tissue diseases were ruled out.resultsneurological deterioration persisted despite immediate provision of continuous \n full - heparinization with concomitant rigorous control of blood pressure . \n endovascular treatment consisting of bilateral stenting was undertaken . \n ten days later , the patient was discharged with mild hemiparesis and resuming normal activity after 3 months.conclusionsbicad with concomitant inadequate collaterals from the circle of willis may predispose to hypoperfusion which might not respond to the usual conservative treatment prompting for flow reestablishment . moreover \n , isolated rigorous cough can cause acute spontaneous bicad even among patients without any risk factors .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: chronic kidney disease ( ckd ) is a very common complication of diabetes mellitus ( dm ) . \n it is defined as the presence of abnormalities in renal structure or function for longer than three months , with implications to healthy . \n the diagnostic criteria for ckd consist of the presence of one or more biomarkers of kidney parenchyma injury such as albuminuria and/or a glomerular filtration rate ( gfr ) lower than 60 ml / min/1.73 m over longer than three months . \n the complications of diabetic nephropathy , such as end stage renal disease and cardiovascular events , are responsible for an increased morbidity and mortality among diabetic patients . \n therefore , it is very important to study molecular and metabolic mechanisms involved with the development and progression of renal dysfunction in dm , since this could contribute to the development of new therapeutic strategies . \n emerging evidence suggests that inflammatory pathways play an important role in the development and progression of diabetic nephropathy . \n it has been reported that t cells and inflammatory cytokines exert central roles in the development of renal disease in dm . \n moreover , hyperglycemia can induce the expression of several proinflammatory cytokines , such as interferon gamma ( inf- ) , interleukin-6 ( il-6 ) , and tumor necrosis factor - alpha ( tnf- ) , leading to the development of a chronic subclinical inflammatory status in dm . \n the deficiency of interleukin-10 ( il-10 ) , an anti - inflammatory cytokine , may also be associated with this increased inflammatory status . \n the interrelation between inflammation and metabolic abnormalities in dm may lead to endothelial injury and the release of von willebrand factor ( vwf ) . \n increased levels of vwf , a biomarker of endothelial dysfunction , have been associated with renal disease in type 1 ( dm1 ) and type 2 diabetes mellitus ( dm2 ) [ 8 , 9 ] . \n vwf promotes platelet adhesion at vascular damage sites , where it mediates the progression of thrombus formation . \n elevated levels of vwf can promote microthrombi formation in vasculature , leading to hypercoagulability status and formation of d - dimer , which is a fragment of fibrin degradation and has also been associated with diabetic nephropathy [ 11 , 12 ] . \n adamts13 ( a disintegrin and metalloproteinase with thrombospondin type 1 motif , member 13 ) is an enzyme responsible for cleavage of large multimers of vwf . \n an imbalance between vwf and adamts13 may also contribute to the development of microvascular complications in diabetic patients . in a previous study \n , we have described the association between vwf , adamts13 , and d - dimer with different levels of renal dysfunction in dm1 patients and we have raised the hypothesis that inflammation could be associated with hypercoagulability in patients with diabetic nephropathy \n . therefore , the aim of the present study was to investigate the association between the haemostatic biomarkers vwf , adamts13 , and d - dimer , the proinflammatory cytokines inf- , il-6 , and tnf- , and the anti - inflammatory cytokine il-10 with ckd in dm1 patients . \n all procedures performed in this study were in accordance with the 1964 declaration of helsinki and its later amendments or comparable ethical standards . \n this study was approved by the research ethics committee of federal university of minas gerais ( caae , 0392.0.203.000 - 11 ) and informed consent was obtained from all individual participants included in the study . \n the clinical records of all 240 dm1 patients receiving assistance at endocrinology outpatient services of the university hospital ( hospital das clnicas ) and santa casa / belo horizonte , brazil , from november 2011 to september 2012 , were analyzed . \n after application of exclusion criteria , 125 patients with clinical and laboratorial diagnosis of dm1 , according to american diabetes association criteria , from 18 to 60 years of age , were selected for this study . \n dm1 patients with hepatic disease , alcoholism , haemostatic abnormalities , malignant diseases , acute infectious , pregnancy , undergoing hemodialysis , and history of kidney transplantation and cardiovascular diseases were excluded from the study . a detailed history and clinical variables of each patient \n were obtained from medical records : age , sex , body mass index ( bmi ) , diabetes duration , presence of diabetes complications such as retinopathy and neuropathy , and use of medicines such as angiotensin converting enzyme inhibitor ( acei ) , angiotensin antagonist , thyroxine , statin , and acetylsalicylic acid ( aas ) . \n dm1 patients were divided into two groups : with ckd ( albuminuria 30 mg / g and/or gfr < 60 ml / min/1.73 m ) , n = 65 ; and without ckd ( albuminuria < 30 \n mg / g and gfr 60 ml / min/1.73 m ) , n = 60 . \n the presence of increased albuminuria and reduced gfr was confirmed in two out of three occasions , over a period between three and six months . \n hba1c was determined by immunoturbidimetric method in edta whole blood samples and creatinine was determined by enzymatic method in serum samples , using johnson & johnson dry chemistry technology kits ( ortho clinical diagnostics ) and vitros 4600 analyser . \n the gfr was estimated using the chronic kidney disease epidemiology collaboration ( ckd - epi ) formula based on creatinine . \n urinary albumin excretion ( uae ) was determined in urine samples collected after at least 4 hours of urinary retention in the morning , and urinary albumin was normalized by urinary creatinine . \n urinary albumin was evaluated by immunoturbidimetric method and urinary creatinine was assessed by enzymatic method , using johnson & johnson dry chemistry technology kits ( ortho clinical diagnostics ) and vitros 4600 analyser . \n inf- , il-6 , il-10 , and tnf- plasma levels were determined by flow cytometry , using human basic kit flowcytomix ( ebioscience ) , following the manufacturer 's recommendations . \n data acquisition and analysis were performed in dual - laser facs caliber tm flow cytometer ( bd biosciences pharmingen , san jose , ca , usa ) , using the bd bioscience cba software . \n vwf , adamts13 antigen , and d - dimer plasma levels were determined by enzyme - linked immunosorbent assay ( elisa ) , using imubind vwf kit ( american diagnostica ) , imubind adamts13 kit ( american diagnostica ) , and asserachrom d - di kit ( stagodiagnostica ) , respectively . \n adamts13 activity was assessed by fluorescence resonance energy transfer ( fret ) assay , using actifluor adamts13 activity kit ( sekisui diagnostics ) . \n intra- and interassay coefficients of variations were , respectively , 9% and 13% for vwf , 4.0% and 7.3% for adamys13 antigen , < 6% and < 10% for d - dimer , and 4.1% and 4.4% for adamts13 activity . \n data normally distributed were expressed as mean sd and were compared by student 's t - test . \n data not normally distributed were expressed as median ( percentiles 25%75% ) and were compared by mann - whitney u test . \n categorical variables were expressed as frequencies and compared using chi - square test ( ) . \n association between haemostatic and inflammatory biomarkers with ckd was evaluated by bivariate and multivariate logistic regression analysis and odds ratio was calculated . \n variables included in multivariate logistic regression analysis were previously associated with ckd in bivariate logistic regression analysis ( p < 0.2 ) and consisted of use of acei or angiotensin antagonist , use of statin , and use of aas . \n correlations between proinflammatory cytokines and the anti - inflammatory ones and between inflammatory and haemostatic biomarkers were performed using spearman correlation test . \n characteristics and clinical variables of 125 dm1 patients included in this cross - sectional study are presented in table 1 . \n patients with ckd had lower bmi ( p = 0.030 ) and a higher frequency of use of ieca or angiotensin antagonist ( p < 0.001 ) , statin ( p < 0.001 ) , and aas ( p = 0.001 ) than patients without ckd . \n there were no significant differences between the groups regarding age , sex , diabetes duration , hba1c , use of thyroxine , and presence of neuropathy . \n however , a higher frequency of retinopathy in group of patients with nephropathy as compared to patients without ckd ( p < 0.001 ) was observed . \n inf- , tnf- , il6 , and il-10 plasma levels were higher in patients with ckd \n as compared to those without nephropathy ( p = 0.001 , p = 0.004 , p = 0.016 , and p = 0.030 , resp . ) \n patients with ckd also presented elevated plasma levels of vwf , adamts13 antigen , adamts13 activity , d - dimer and vwf / adamts13 activity ratio , and a reduced adamts13 activity / antigen ratio than those without nephropathy ( p < 0.001 , p < 0.001 , p = 0.003 , p < 0.001 , p = 0.006 , and p < 0.001 , resp . ) . \n the results of the bivariate logistic regression analysis are presented in table 2 . in general , \n inflammatory and haemostatic biomarkers were significant associated with ckd , corresponding to or of 1.021 ( 1.0081.035 ) for inf- , 1.006 ( 1.0021.011 ) for tnf- , 1.224 ( 1.0511.426 ) for il-6 , 1.002 ( 1.0001.003 ) for il-10 , 1.003 ( 1.0011.004 ) for vwf , 1.005 ( 1.0021.007 ) for adamts13 antigen , 1.030 ( 1.0091.051 ) for adamts13 activity , 0.667 ( 0.4900.907 ) for vwf / adamts13 antigen , 1.129 ( 1.0311.236 ) for vwf / adamts13 activity , 7 10 ( 4 101 10 ) for adamts13 activity / antigen , and 1.008 ( 1.0041.012 ) for d - dimer . \n these associations remained significant even after adjustment for use of acei or angiotensin antagonist , statin , and aas , as shown by multivariate regression logistic analysis ( table 2 ) . \n all proinflammatory cytokines il-6 , inf- , and tnf- presented a significant correlation ( p < 0.001 ) with the anti - inflammatory cytokine il-10 ( r = 0.689 , 0.805 , and 0.813 , resp . ) , as presented in figure 1 . \n inf- presented a significant correlation with vwf , adamts13 antigen , vwf / adamts13 activity ratio , and adamts13 activity / antigen ratio ( r = 0.264 , 0.192 , 0.220 , and 0.385 , resp . ) . \n tnf- was significantly correlated with adamts13 antigen , adamts13 activity / antigen ratio , and d - dimer ( r = 0.291 , 0.337 , and 0.217 , resp . ) . \n il-10 showed a significant correlation with vwf , vwf / adamts13 activity ratio , adamts13 activity / antigen ratio , and d - dimer ( r = 0.212 , 0.192 , 0.270 , and 0.244 , resp . ) . \n in our study , higher levels of inf- , il-6 , and tnf- were observed in dm1 patients with ckd in comparison to those without nephropathy , which is in agreement with other studies [ 1722 ] . \n hyperglycemia is associated with increased production of advanced glycation end - products ( ages ) , which can bind to their receptors present on the surface of endothelial cells , smooth muscle cells , fibroblasts , lymphocytes , monocytes , and macrophages , resulting in activation of nf-b which can enhance inf- transcription in t cells and il-6 and tnf- transcription in diabetic glomerulus [ 2325 ] . \n large amounts of inf- are produced by t helper 1 ( th1 ) cells , promoting activation of macrophages and cell - mediated immunity , which may mediate tissue injury in diabetic patients . \n tnf- can induce monocyte chemoattractant protein-1 ( mcp-1 ) expression in mesangial cells , resulting in macrophage recruitment and accumulation in glomerulus , exacerbating kidney inflammation . \n hyperglycemia also causes enhanced cycle oxygenize-2 ( cox-2 ) expression and prostaglandin e2 ( pge2 ) production , which induces il-6 expression in tubular epithelial cells , contributing to the development of glomerulosclerosis , interstitial fibrosis , and albuminuria . \n furthermore , il-6 and tnf- are cytotoxic cytokines and may contribute to glomerulus endothelial cells damage , which can stimulate the release and expression of procoagulant molecules , such as vwf , plasminogen activator inhibitor-1 ( pai-1 ) , and tissue factor . \n they can also inhibit the expression of anticoagulant molecules , such as thrombomodulin , by endothelial cells , resulting in hypercoagulability state , which may also contribute to progression of diabetic nephropathy . \n reported that il-6 may be associated with the progression of nephropathy in dm1 patients with microalbuminuria and a meta - analysis has demonstrated that il-6 is a valid biomarker predicting the progression of nephropathy in dm2 . \n moreover , urinary tnf- and soluble tnf receptors 1 and 2 ( tnfr1 and tnfr2 ) have been shown to be significant predictors of gfr decline in dm2 patients [ 32 , 33 ] . \n therefore , it is possible to suggest that hyperglycemia promotes the development of a chronic low grade inflammation in renal parenchyma , characterized by increased levels of proinflammatory cytokines inf- , tnf- , and il-6 levels , which may be involved in the pathogenesis of diabetic nephropathy . \n il-10 is produced by t helper 2 ( th2 ) cells and plays an important role in limiting the cascade of proinflammatory cytokines activation and downregulating t cell - mediated immune responses . \n treatment of rats with il-10 reduced proteinuria and inflammatory status and attenuated renal injury . a lower frequency of cg genotype polymorphism il-10 -1082g / a , which is related to higher expression of this cytokine , was associated with nephropathy in dm2 . in our study , patients with ckd presented higher levels of il-10 than patients without nephropathy , which is in agreement with other study . this result could be partially explained by a compensatory mechanism , in which il-10 plasma levels increase as a consequence of higher plasma levels of proinflammatory cytokines inf- , tnf- , and il-6 in patients with nephropathy to regulate the inflammatory status , since il-10 is an anti - inflammatory cytokine . \n the significant correlation between proinflammatory cytokines and il-10 observed in this study may corroborate this hypothesis . \n this compensatory increase in il-10 levels could also prolong the course of nephropathy in dm1 patients . \n elevated plasma levels of vwf were associated with diabetic nephropathy in the present study , which was also verified by other authors [ 9 , 37 ] . \n it was demonstrated that some inflammatory cytokines , such as inf- , il-6 , and tnf- , can promote the release of vwf [ 29 , 38 ] . \n indeed , a significant correlation between vwf and inf- was observed in this study , which indicates that the interrelation between inflammation and endothelial dysfunction may be involved in the pathogenesis of diabetic nephropathy . \n adamts13 antigen and activity plasma levels were also elevated in dm1 patients with ckd as compared to those without renal dysfunction , which was also found in other studies . \n this result may be explained by a compensatory mechanism , by which adamts13 synthesis is increased due to the marked elevation in vwf plasma levels , keeping vwf / adamts13 antigen ratio unchanged . \n however , the rise in adamts13 antigen levels was not accompanied by a proportional increase in adamts13 activity , since adamts13 activity / adamts13 ag ratio was lower and vwf / adamts13 activity ratio was higher in dm1 patients with nephropathy . an in vitro study has demonstrated that il-6 can inhibit adamts13 activity , compromising the proteolysis of vwf . tnf- and inf- presented a significant negative correlation with adamts13 activity / antigen ratio and a significant positive correlation with adamts13 antigen , but not with adamts13 activity , which is in agreement with the hypothesis that the inflammatory status induced by hyperglycemia may also result in reduced activity of adamts13 and , consequently , in reduced proteolysis of vwf , leading to an imbalance between vwf and adamts13 activity in dm1 patients with ckd . \n this imbalance may promote microthrombi formation and hypercoagulability status , resulting in elevated d - dimer plasma levels , which was also observed in dm1 with ckd in this study and other studies [ 11 , 12 ] . \n a significant positive correlation between d - dimer and tnf- observed in the present study reinforces the link between inflammation and hypercoagulability . \n increased proinflammatory cytokines plasma levels have been associated with the development of cardiovascular disease in dm1 patients . \n as these cytokines can promote the release of procoagulant molecules , such as vwf , and possibly can reduce adamts13 activity , promoting an imbalance between vwf and adamts13 activity and , consequently , microthrombi formation , it is possible to suggest that the chronic low grade inflammation present in patients with ckd may be , at least partially , responsible for the link between diabetic nephropathy and high risk of cardiovascular outcomes . however , longitudinal studies are still necessary to elucidate this issue . in conclusion , increased plasma levels of proinflammatory cytokines inf- , tnf- , and il-6 , anti - inflammatory cytokine il-10 , and haemostatic biomarkers vwf , adamts13 antigen , adamts13 activity , and d - dimer are associated with ckd in dm1 patients , and the imbalance between vwf / adamts13 activity and adamts13 activity / antigen is correlated with inflammatory cytokines , suggesting that an interrelation between inflammation and hypercoagulability may contribute to the development and progression of renal disease in dm1 . \n these findings may be useful for guiding future longitudinal studies aiming at a better comprehension of the interrelation between inflammation and hypercoagulability with diabetic nephropathy progression , enabling the identification of new biomarkers of renal disease progression and the introduction of new therapeutic strategies .", "role": "user" }, { "content": "this study aimed at investigating the association between haemostatic biomarkers , proinflammatory , and anti - inflammatory cytokines with chronic kidney disease in type 1 diabetic patients . \n patients were divided into two groups : with nephropathy ( albuminuria 30 mg / g and/or gfr < 60 ml / min/1.73 m2 ) , n = 65 ; and without nephropathy ( albuminuria < 30 mg / g and gfr 60 ml / min/1.73 m2 ) , n = 60 . \n inf- , il-6 , il-10 , and tnf- plasma levels were determined by flow cytometry . \n vwf , adamts13 antigen , and d - dimer plasma levels were determined by enzyme - linked immunosorbent assay and adamts13 activity was assessed by fluorescence resonance energy transfer assay . \n elevated levels of inf- , vwf , adamts13 antigen , d - dimer , and reduced adamts13 activity / antigen ratio were observed in patients with nephropathy as compared to those without nephropathy ( p = 0.001 , p < 0.001 , p < 0.001 , p < 0.001 , and p < 0.001 , resp . ) . \n cytokines and haemostatic biomarkers remained associated with nephropathy after adjustments ( use of statin , acetylsalicylic acid , angiotensin converting enzyme inhibitor , and angiotensin antagonist ) . \n inf- , tnf- , and il-10 significantly correlated with haemostatic biomarkers . \n inflammatory and hypercoagulability status are associated with nephropathy in type 1 diabetes mellitus and an interrelationship between them may play an important role in pathogenesis of diabetic nephropathy .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: systemic embolization is an unfortunate sequel of infective endocarditis ( ie ) that can occur despite an appropriate therapy . \n cardiac embolization is seen in one - third to one - half of the patients , and the most common complication is heart failure ( more common in aortic valve ie than mitral valve ) . \n coronary embolization is not uncommon , and micro - emboli are seen in up to two - third of patients at autopsy . despite the high incidence of coronary embolism , clinically significant transmural infarcts are very rare with ie . \n a 69-year - old male presented to the mount sinai saint luke 's emergency department with intermittent fever and increased urinary frequency for 1 week . \n his past medical history was significant for streptococcus sanguinis tricuspid valve endocarditis , bioprosthetic aortic valve replacement , coronary artery disease ( status of post - triple vessel coronary artery bypass grafting ) , paroxysmal atrial fibrillation ( afib ) , and type-2 diabetes mellitus . on physical examination , his vitals were notable for an irregular pulse of 112 beats / min , blood pressure of 136/77 mm hg , respiratory rate of 18/min , rectal temperature of 98f , and oxygen saturations of 98% on room air . \n there was a cardiac grade 2/6 ejection systolic murmur 6 cm of water at 45 position . \n laboratory studies were significant for glucose 204 mg / dl and troponin - i 0.05 ng / ml ( normal < 0.034 ng / ml ) . \n urinalysis was positive for leukocyte esterase and pyuria with 3550 white blood cells / high - power field . \n electrocardiogram ( ecg ) on admission showed sinus rhythm with first degree av block and frequent premature atrial complexes . \n the patient was administered one dose of levofloxacin after drawing blood cultures which came back positive for gram - positive cocci . on the next day , his antibiotics \n were changed to vancomycin and gentamicin for suspected endocarditis . on day 1 of admission , \n the patient developed acute pulmonary edema and hypoxia following an episode of sub - sternal crushing chest pain . \n repeat ecg showed afib with rapid ventricular response and st - depressions in leads ii , avf , and v2v6[figure 1 ] . \n he was managed with nitroglycerine , furosemide , noninvasive positive pressure ventilation , and was transferred to cardiac care unit . \n immediate trans - thoracic echocardiogram ( tte ) did not show any vegetation or aortic insufficiency . \n his next troponin - i came back to 10.19 ng / ml and ck - mb was 163.8 ng / ml ( 0.54.7 ng / ml ) . \n he was treated for non - st elevation myocardial infarction with intravenous heparin , aspirin , clopidogrel , statin , and a beta blocker . \n the patient could not tolerate transesophageal echocardiography ( tee ) and had a repeat tte , which showed inferior and lateral akinesis , moderate systolic dysfunction , and probable vegetation on the noncoronary cusp of aortic valve . \n electrocardiogram demonstrating atrial fibrillation with rapid ventricular response and st - depressions in leads ii , avf , and v2v6 on day 3 of admission , blood cultures grew enterococcus faecalis . \n his troponin - i level peaked at 172.09 ng / ml . a presumptive diagnosis of enterococcal endocarditis of prosthetic aortic valve with embolic myocardial infarction from vegetation was established . eventually , the patient underwent tee . \n it showed moderately decreased left ventricular systolic function with an ejection fraction of 40% , regional wall motion abnormalities with mid and basal anterior and lateral akinesis , bioprosthetic aortic valve with an abscess ( thickened intervalvular fibrosa ) , and small vegetation on the left coronary cusp . \n coronary angiography revealed new 99% occlusion of the left main coronary artery ( lmca ) and proximal left circumflex artery , chronic total occlusion of ostial left anterior descending artery ( lad ) and right coronary artery , patent saphenous vein graft to posterior descending artery , and patent left internal mammary artery graft to the lad artery . \n the patient improved clinically on medical management and stayed hemodynamically stable . on day 9 of admission , \n the patient underwent revision of aortic valve replacement , drainage of annular abscess , and lmca embolectomy . \n his aortic valve as well as the embolic debris was removed from lmca grew e. faecalis . \n subsequently , he was discharged to the skilled nursing facility in a stable condition where he completed 6 weeks of intravenous ampicillin . \n prosthetic valve endocarditis ( pve ) is a serious and potentially life - threatening infection . \n pve develops in 14% of patients during the 1 year following valve replacement , and in approximately 1% per year thereafter . \n it is usually hospital - acquired and common pathogens are coagulase - negative staphylococcus and s. aureus . \n pve developing 12 months after surgery is termed as late pve , which is usually community - acquired and common pathogens include streptococcal species and s. aureus . \n enterococcus faecalis is a nonmotile , facultative anaerobe with plasmid - encoded hemolysin called cytolysin , which is important for pathogenesis in animal models of infection . \n enterococcal species are the third leading cause of native valve endocarditis causing 510% of the early pve and 812% of late pve cases . \n enterococcal endocarditis has been reported in patients with systemic lupus erythematosus , heroin addicts , following legal abortion and complicating colonoscopy in heyde 's syndrome . \n only six cases have been reported of coronary embolism from ie resulting in sudden cardiac death secondary to lmca occlusion , left ventricular rupture , and lmca embolism after abortion . \n coronary embolism secondary to enterococcal endocarditis has been reported with papillary muscle rupture due to circumflex artery occlusion arising from native aortic valve vegetation . \n lmca embolism from vegetative material is extremely rare , and fatal reports have been described with native aortic valve and mitral valve endocarditis , and none of them were conclusively enterococcal . \n use of thrombolytics has been largely unfavorable due to increased risk of intracerebral hemorrhage which is mainly due to mycotic aneurysms and cerebral infarcts , which are sequels of ie . \n percutaneous transluminal coronary angioplasty carries a risk of re - occlusion due to a mobile embolus , risk of distal embolization , and development of mycotic aneurysm at the balloon dilation site . furthermore , inserting a stent in bacteremic patients is also controversial due to the risk of seeding of the stent . \n good prognosis can be achieved with surgery in patients with native valve endocarditis and pve , who have moderate to severe heart failure and in patients with late pve . \n patients with ie and large vegetation have lower mortality and embolic events if an approach with early surgical intervention is undertaken . in our patient , \n previous coronary artery bypass graft with good coronary flow resulted in a good prognosis despite occlusion of lmca by the vegetation . \n to our research , this is the first case of lmca embolism resulting from pve with e. faecalis . \n embolic coronary occlusion should be included in the differential diagnosis of chest pain and increased troponin levels in patients with confirmed or suspected ie because the therapeutic implications are complex and usual measures such as thrombolysis may be dangerous . \n \n ", "role": "user" }, { "content": "context : coronary embolization is potentially a fatal sequela of endocarditis . although the primary cause of acute coronary syndrome is atherosclerotic disease , it is imperative to consider septic embolism as an etiological factor.case report : herein , we report a case of ventricular fibrillation and st - segment depression myocardial infarction occurring in a patient who initially presented with fever and increased urinary frequency . \n coronary angiography revealed new 99% occlusion of the left main coronary artery ( lmca ) . \n transesophageal echocardiography showed bioprosthetic aortic valve with an abscess and vegetation . \n histologic examination of the embolectomy specimen confirmed the presence of thrombus and enterococcus faecalis bacteria . \n subsequently , the patient was discharged to the skilled nursing facility in a stable condition where he completed 6 weeks of intravenous ampicillin.conclusion:we present a rare case of lmca embolism due to prosthetic valve endocarditis . \n the present report also highlights the diagnostic and therapeutic challenges associated with such patients .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: deficits in working memory ( wm ) , a limited capacity system that supports the online manipulation and temporary storage of information , are considered to be a hallmark of alzheimer 's disease ( ad ) , even in its earliest stages . \n deficits in span tasks [ 3 , 4 ] and dual task procedures [ 5 , 6 ] emerge in the early stages of ad , and have been attributed to central executive dysfunction . \n of particular interest is the finding that individuals at genetic risk of developing ad show poor wm performance relative to those not at genetic risk [ 8 , 9 ] , highlighting the potential of such tasks to detect early ad . \n this study considered the usefulness of the subject - performed task ( spt ) manipulation in improving wm in early ad and healthy older adult controls , in a task measuring the ability to verbally repeat short sequences of instructions . \n the subject - performed task involves verbally presenting participants with words or instructions consisting of sets of simple actions ( e.g. , open the book ) , which they are required to enact during this encoding phase . \n recall of the actions is then subsequently tested , typically via verbal recall or recognition . in general \n , research shows that enacted encoding facilitates later memory performance , relative to control conditions in which no enactment occurs during encoding . \n cohen originally hypothesised that spt effects are nonstrategic in nature , such that encoding during spt does not rely on active verbal or organisational strategies that are necessary during basic verbal encoding . \n the enactment effect may also be attributable to the development of a richer set of representations supporting performance including visual , spatial , and motoric information , or specifically the impact of increased motor coding . \n alternatively kormi - nouri proposes that enacted encoding is strategic in nature and that it is the involvement of the self during spt that leads to enhanced remembering . \n spt has been found to enhance recall in several clinical groups , including parkinson 's disease and autism spectrum disorder ( asd ) , yet research with ad participants has generated mixed findings . \n several studies have explored this effect , all using episodic long - term memory ( ltm ) tasks [ 1720 ] . the first study to investigate spt in individuals with ad failed to find an enactment effect on ltm , and of those studies that have observed an effect , \n the majority have found it in instances of cued recall but not free recall . \n in contrast , the most recent study to investigate the enactment effect in mild ad patients demonstrated superior recall for spt relative to verbal - only encoding tasks in free recall , as well as in semantic - cued recall and object - cued recall . \n in fact , this study demonstrated that the benefit of object - cued recall was greater for ad patients than neurologically intact older adults , thus highlighting encoding specificity as a principle that might enhance recall in ad . \n to summarize , the present study examines the advantage of spt over verbal - only encoding tasks in individuals with early ad using a recently developed wm task . to our knowledge , this is the first study of its type to adopt a wm approach to enactment with ad patients . \n the present study uses a modified version of the following instruction task , which was designed to explore links between wm decrements and difficulty in retaining , repeating , and implementing complex instructions . in the original version of this task , children heard verbal instructions ( e.g. , touch the red pencil and put it in the black box ) and were required to either perform the sequence or repeat it immediately after presentation . as a wm task , \n it features a minimal delay between presentation and test , and instruction sequences that are comparatively shorter than those most frequently used in the spt literature . \n as the instruction task has been shown to rely heavily on wm abilities , and because patients with early ad have wm deficits , we predicted that this group would perform poorer relative to an older adult control group . \n it was expected that healthy older adult control participants would show a substantial benefit of encoding - based enactment . \n as the benefit of spt has been suggested to rely on the involvement of the self , and because research suggests that ad might be accompanied by a disrupted sense of self ( but see for evidence of an intact self - reference effect in ad ) , we might predict that individuals with ad will fail to benefit from enacted encoding . \n in contrast , if instead the benefit of enacted encoding relies more on automatic , nonstrategic and multimodal encoding , we predict that spt will enhance remembering in ad patients , as well as older adult controls . in other words , \n the potential nonstrategic nature of spt might allow patients to overcome the executive demands involved in constructing memory representations and thus facilitate their recall performance . \n twelve individuals diagnosed with mild ad ( 5 males ) and two diagnosed with mild cognitive impairment ( mci ; both female ) were recruited for participation from a memory clinic in leeds ( uk ) , and all received formal diagnosis by a psychiatrist . a number of participants were being medicated with acetylcholinesterase inhibitors at the time of testing , but medication was stabilised for at least 8 weeks prior to testing . regarding ad severity , \n all patients scored above 19 on the mini mental state examination ( mmse ) ( mean = 23.42 , sd = 3.18 ) , both patients with mci scored 25 . \n fifteen older adult controls ( 5 males ) were recruited from a volunteer panel held by the university of leeds ( uk ) . \n older adult controls reported themselves to be in good physical and mental health ; none were taking any medication that is known to affect the central nervous system , and all were living independently at the time of testing . \n participants were screened for symptoms of ad using the mmse , all scored above the cut - off of 26 points ( mean = 29.07 , sd = 0.70 ) . there were no significant group differences in age ( t(27 ) = 1.79 , p = 0.09 , d = 0.66 ) or predicted full scale iq ( fsiq ; t(27 ) = 1.44 , p = 0.16 , d = 0.54 ) ( national adult reading test ( nart ) ) . \n mean fsiq scores were 116.36 ( sd = 10.26 ) ( range 92128 ) in the ad group and 121.2 ( 7.77 ) ( range 103129 ) in the older adult control group . \n mean age of ad participants was 82.43 ( 6.14 ) ( range 7192 ) and 78.60 ( 5.41 ) ( range 6890 ) in the older adult group . \n the method used was a modified version of that used by wojcik et al . . \n action - object pairings were generated by combining 8 actions ( thumb , spin , push , drag , flip , tap , lift , and shake ) with 15 objects ( erasers , rulers , pens , boxes , and folders with red , yellow , and blue versions of each ) . \n each action was combined with an object to create action - object pairs ( e.g. , tap the yellow ruler ) . \n instruction sequences were then generated ; they contained between three and seven action - object pairs ; for instance , flip the red ruler ( 1 ) , then spin the blue pen ( 2 ) , then shake the yellow box ( 3 ) is an example of a three action - object sequence . \n importantly , in order to minimize ltm contributions and focus on wm , there were no meaningful preexisting relationships between any of the actions or objects . \n as instruction sequences included up to seven action - object pairs , some colours ( e.g. , red ) and objects ( e.g. , box ) appeared more than once within a single instruction sequence , but no sequence used the same particular object ( e.g. , red box ) twice . \n participants attempted 5 sequences at each length , beginning with sequences containing 3 pairs before progressing to the next sequence length . \n this continued until all sequence lengths had been completed or until the participant was unable to correctly recall any action - object pairs from the instruction sequence . \n instructions were read out loud by the experimenter ( verbal - only task , vt ) or read by the experimenter and performed by the participant themselves ( subject - performed task , spt ) ( see figure 1 for a schematic representation of each encoding task ) . in the spt condition , \n each action - object pair was performed by the participant immediately after verbal presentation ; for instance , tap the yellow ruler \n enactment>. in the vt condition , participants listened only and were restricted from touching any of the objects . \n the performance of actions was self - paced in the spt condition , and a two - second delay separated verbal presentation of each action - object pair in the vt condition to control for this . \n in both conditions a test phase immediately followed verbal presentation of each instruction sequence , in which participants were asked to verbally recall the entire multiaction sequence . \n a practice phase , consisting of two practice trials ( each involving two action - object pairs ) , was given prior to each condition , and all actions were demonstrated to participants prior to testing . \n conditions were separated by a ten - minute break in which the nart and mmse were administered to assess cognitive impairment and estimate fsiq in both groups . written informed consent was obtained from all participants and full ethical approval was granted by the university of leeds ' ethics committee prior to the start of any testing . \n ethical approval for this research was also granted by the nhs ethics committee prior to testing . \n performance was scored as the mean proportion of elements correctly recalled from each sequence ; that is , participants received credit for each individual action , object , or colour correctly recalled . \n analysis of serial order recall ( elements recalled in the order that they were presented in ) yielded evidence of floor effects , with several participants failing to recall any elements in their correct serial positions . therefore , as serial ordering mechanisms were not of primary interest in this experiment , free order performance ( elements recalled regardless of original order ) is reported here . analysis was carried out on three action - object pair sequences and four action - object pair sequences , as all participants in both groups completed these sequence lengths . \n a 2 ( group ) 2 ( encoding condition ) 2 ( sequence length ) mixed anova was performed . \n this revealed a main effect of group , f(1,27 ) = 14.16 , p = 0.001 , and p = 0.34 , such that older adult control participants recalled significantly more elements from the action - object instruction sequences than did ad patients . \n a main effect of encoding condition was also found , f(1 , 27 ) = 46.71 , p < 0.001 , and p = 0.63 , and this was in the direction predicted , as recall was significantly higher in the spt condition compared with the vt condition , across group and sequence length . \n analysis also revealed a main effect of sequence length , f(1,27 ) = 47.5 , p < 0.001 , and p = 0.64 , with the proportion of correctly recalled information being higher for 3 action - object pair sequences than for 4 pair sequences . \n there was no significant interaction between encoding condition and group , f(1,27 ) = 2.67 , p = 0.11 , and p = 0.09 , though the effects of spt were slightly larger in the older adult group . \n there was also no interaction between condition and sequence length , f(1,27 ) = 1.09 , p = 0.31 , and p = 0.04 . \n overall , spt led to improved performance across participant groups and number of action - object pairs . \n a significant interaction between sequence length and group was found , f(1,27 ) = 10.12 , p = 0.004 , and p = 0.27 . \n inspection of figure 2 suggests that older adults show a greater proportional decline when sequence length is increased from 3 action - object pair sequences to 4 pair sequences . \n this is regardless of encoding condition , as there was no significant 3-way interaction , f(1,27 ) = 0.87 , p = 0.36 , and p = 0.04 . \n in order to explore the group length interaction , data was collapsed across encoding condition , and paired samples t - tests indicated that increasing sequence length had a greater effect on the recall performance of older adult controls than it did on ad participants , t(29 ) = 7.08 , p < 0.001 , and d = 1.38 , and t(27 ) = 2.95 , p = 0.006 , and d = 0.56 , respectively . \n this is likely due to the already relatively poor performance of ad participants at the shorter sequence length . \n all analyses were repeated without mci participants to determine whether this had any effect on findings ; this was not the case ; all basic patterns of findings were replicated . \n this study examined the memory performance of individuals with early ad and older adult controls on an instruction task that required the temporary storage in wm and subsequent recall of action - object sequences , following self - enactment ( spt ) or a baseline control condition ( vt ) . \n participants with ad tended to show a deficit in remembering relative to older adult controls , supporting extensive existing literature indicating wm deficits in early ad . \n the primary focus of the present study was to establish whether the wm performance of ad patients would benefit from self - enactment at encoding . \n the findings reveal that verbal recall in both older adults and individuals with ad was significantly facilitated by the performance of actions on objects at encoding . to our knowledge , this is the first study to indicate a beneficial enactment effect on wm in older adults and ad patients , and it suggests that this manipulation might have useful applications for the amelioration of cognitive deficits in early ad . \n more generally , the basic task of following and recalling instructions might be useful in detecting early stage ad . the ability to follow instructions has been observed to be particularly deficient in children identified as having poor wm ; an analogous deficit may also emerge as a result of ad . \n what implications might these findings have both for the enactment effect in wm and for the nature of the cognitive deficit in ad ? \n wojcik et al . observed substantial benefits of encoding - based enactment in a similar wm task in typical children and children with autism spectrum disorder , though accuracy was measured by physical enactment rather than verbal recall . \n taken together , these findings indicate a positive encoding - based enactment effect in wm across populations and response measures . \n this benefit might reflect a development of a richer set of representations supporting performance including visual , spatial , and motoric information or specifically the impact of increased motor coding . linked to this , \n spt - based enactment has also been attributed to a boost in item - based encoding , possibly at the expense of relational information , which may be relevant to the improvements observed in the present study on a task that did not emphasize serial order . \n if enactment does indeed lead to capture of information from multiple sources , one storage capacity for integrating and retaining such information may be the episodic buffer component of wm recently developed by baddeley . \n an important aspect of many theoretical approaches to enactment / spt is that any gains from this manipulation are automatic and nonstrategic in nature . \n alzheimer 's disease is characterised by a relative preservation of automatic cognitive processes and a progressive loss of controlled cognitive processes . \n this may help explain why the ad group were able to also benefit from this manipulation despite their possible deficits in wm control and executive ability . \n this observation of significant enactments in wm on free recall tasks differs from some findings in the ltm literature [ 17 , 19 ] , though it fits with work by lekeu and colleagues . \n a common factor between that work and the present study is the availability of cues at both encoding and retrieval . whilst previous research by herlitz et al \n . found no memory improvement from spt on free recall tasks , they showed that ad patients experience an enactment effect in semantic - cued recall . \n in fact , herlitz and colleagues demonstrated that enacted encoding is sufficient to improve the ltm performance of patients with severe dementia when semantic cues are present at recall . \n this suggests that patients require support at both encoding and retrieval in order for enhanced recall via self - performance . in our study \n , objects remained on view in the response phase , though recall was verbal in nature . \n it may be that the enactment effect is indeed nonstrategic in nature , but in ad it relies on cue availability in order to enable significant performance facilitation . \n in contrast , kormi - nouri has argued that enactment emphasizes involvement of the self , a form of processing that has been suggested to be impaired in ad . \n the present observation that significant effects of this manipulation were observed in ad might suggest that enactment does not particularly engage the self when used in wm tasks . \n however , conclusions on this issue are necessarily tentative , and the fact that enactment had a slightly larger benefit for older adults than ad patients ( though the interaction was not significant ) means further research will be necessary . \n our results demonstrate a positive encoding - based enactment effect in wm across older adults and patients with early ad . \n findings also support previous research which shows that recall is facilitated in ad by the availability of cues at both encoding and retrieval . due to the nature of the cognitive deficits in ad , replication using this \n group and extension to similar paradigms might prove useful in elucidating the mechanisms responsible for the enactment effect . \n of particular importance is the role that this manipulation might play in ameliorating the cognitive deficits that present in early ad .", "role": "user" }, { "content": "this study examines the enactment effect in early alzheimer 's disease using a novel working memory task . \n free recall of action - object instruction sequences was measured in individuals with alzheimer 's disease ( n = 14 ) and older adult controls ( n = 15 ) . \n instruction sequences were read out loud by the experimenter ( verbal - only task ) or read by the experimenter and performed by the participants ( subject - performed task ) . in both groups and for all sequence lengths \n , recall was superior in the subject - performed condition than the verbal - only condition . \n individuals with alzheimer 's disease showed a deficit in free recall of recently learned instruction sequences relative to older adult controls , yet both groups show a significant benefit from performing actions themselves at encoding . \n the subject - performed task shows promise as a tool to improve working memory in early alzheimer 's disease .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: a 6-year - old , 19 kg , child was admitted to our hospital with symptoms of proximal muscle weakness and a one - month history of difficulty climbing steps . \n preoperative laboratory tests were abnormal : aspartate transaminase ( ast ) 560 iu / l , alanine transaminase ( alt ) 773 \n iu / l , alkaline phosphatase 352 iu / l , lactate dehydrogenase ( ldh ) 4,280 iu / l , creatinine phosphokinase ( cpk ) \n preoperative echocardiography and pulmonary function test were considered to be unnecessary by the attending pediatrician . \n the patient received no premedication . upon arrival in the operating room , standard monitoring , including ekg , pulse oximetry , end - tidal capnography , transesophageal temperature probe , bispectral index ( bis vista , aspect medical systems , the netherlands ) and train - of - four monitor ( tof watch , organon , ireland ) were applied . \n anesthesia was induced with intravenous midazolam 1 mg , fentanyl 25 g , and continuous infusion of propofol . \n bis 40 - 65 was maintained and 30 ma at 2 hz tof was monitored during anesthesia . \n anesthesia was maintained with nitrous oxide 50% in oxygen and end - tidal co2 was maintained at 30 - 35 mmhg . \n intraoperative vital signs were as follows : blood pressure : 92 - 115/50 - 60 mmhg , heart rate : 100 - 107 bpm , oxygen saturation : 100% , and temperature : 36.3. propofol was stopped at the end of surgery . \n following recovery of tof to 90% , neuromuscular blockade was reversed with pyridostigmine 4 mg and glycopyrrolate 0.16 mg . \n the patient opened his eyes spontaneously , responded to verbal command , and was able to lift his head . \n muscular tone was re - evaluated but we did not check the tof . biopsy result confirmed duchenne muscular dystrophy . \n the disease is characterized by severe proximal muscle weakness , progressive degeneration , and fatty infiltration of the muscles . \n progressive and severe muscle atrophy and weakness cause loss of ability to ambulate by the teenager . \n dmd affects the muscles of respiration and is associated with dilated cardiomyopathy , which often leads to death secondary to cardiopulmonary causes . \n patients with dmd are vulnerable to the adverse physiologic effects of general anesthesia and procedural sedation . \n they are at increased risk of rhabdomyolysis , life - threatening hyperkalemia , malignant hyperthermia - like reaction and heart failure when they are exposed to inhalational anesthetics and succinylcholine . \n intravenous anesthetics such as propofol , ketamine and dexmedetomidine are reasonable alternatives and commonly used at variable doses [ 1 - 3 ] . \n however , there is no risk - free choice and a lack of prospective clinical studies to determine the safest anesthetic technique for dmd patients . in order to decrease risks such as rhabdomyolysis \n the responsiveness of dmd patients administered with standard dosage of nondepolarizing neuromuscular blocking agent differs from that in normal patients . \n delayed onset of blockade in dmd following administration of standard dose rocuronium , and the prolonged recovery from rocuronium - induced blockade necessitate the need for careful assessment of neuromuscular function . \n if rocuronium is administered in dmd , assessment of complete neuromuscular recovery ( tof ratio = 0.9 ) by quantitative measurement , such as acceleromyography , is mandatory . \n however , use of reduced electrical current for pediatric tof monitoring may be necessary [ 4 - 6 ] . using succinylcholine for the setup and stabilization of neuromuscular monitoring in children has been reported . however , this method is not appropriate for dmd . \n tof was not established for the child in the recovery room , and we monitored the muscle strength clinically . \n anesthetic induction dosage of propofol decreases with increasing patient age . as such , bolus dose used for children \n are much higher than that of adult . according to the pharmacokinetics of child , initial loading dose and maintenance dose \n target - controlled infusion ( tci ) system of propofol ( diprifusor , fresenius vial sa , france ) is based on adult pharmacokinetic model , and usage in children is limited . \n the limitation of age and body weight for the tci is 16 years - old and 30 kg respectively , and it is difficult to use in younger children . \n bispectral index monitoring has been developed as a tool for measuring the depth of anesthesia in adults , but the use of bis has generated several curious findings in children . \n the nervous system is functionally immature at birth , myelination is rapid during the first 2 years and completed by 7 years of age . \n but some studies showed the validity of bis in children older than 2 years [ 13 - 15 ] . monitoring with bis , \n bis is the most valid monitor to measuring the depth of anesthesia to date . in conclusion , \n we recommend anesthetists to pay close attention to the neurophysiologic and neuromuscular monitoring for patients with duchenne muscular dystrophic .", "role": "user" }, { "content": "duchenne muscular dystrophy is a hereditary disorder characterized by progressive muscle weakness and contracture , and special care during anesthesia is needed in these patients . because inhalational anesthetics and succinylcholine can cause fatal results , intravenous anesthetics are commonly used . \n however , monitorings for the pediatric population are not otherwise specified . \n we report our experience of a 6 year - old boy that underwent muscle biopsy suspicious of muscle dystrophy under general anesthesia . \n the patient received midazolam , fentanyl , propofol and a small dose of rocuronium . \n he was monitored with bispectral index ( bis ) , acceleromyography ( tof ) . at the end of surgery , recovery of tof \n ratio to 90% was evaluated , followed by injection of pyridostigmine and glycopyrrolate . when reversal of neuromuscular block was confirmed quantitatively and clinically , the patient was extubated and he experienced no complication .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: since it s introduction in 1977 , the national health insurance program in korea has paid health care providers on a fee - for - service basis , and the reimbursement for health care providers has been regulated by the government . regulated fee - for - service payment has resulted in an increased volume and intensity of medical care5 ) . \n this led to the creation of the korean resource based relative value scale ( k - rbrvs ) , which remains in force , with continual evolution , to the current day . \n k - rbrvs was developed in 1997 based on the rbrvs of the united states of america ( usa ) , which was established in 1992 , and was introduced in 2001 as an alternative of the previous korean medical fee schedule . \n not unexpectedly , most neurosurgeons are unfamiliar with the details of the k - rbrvs and how changes in the k - rbrvs affects the reimbursement rates for the surgical procedures we perform . \n unfortunately , most physicians might also be unaware of the update process and of the trend of change in relative values ( rvs ) . \n physicians in a wide variety of settings may benefit from understanding the k - rbrvs , and from precisely knowing the trend of change in rvs in our surgical specialty . \n however , to our knowledge no article about this issue in our field has been published yet . in this article , we summarize the k - rbrvs in brief , and discuss on how the relative value ( rv ) of the spinal neurosurgical procedures have changed since the introduction of this system in 2001 . \n we also compare these changes with the brain neurosurgical practices , and finally discuss on the fairness regarding whether if we are properly paid or not , for the practices we do in the spinal neurosurgical field . \n during the 1990 s , policy makers were concerned about the persistent growth of medical expenditures and at the same time they needed a standardized payment system regarding reimbursement for physicians . \n as a solution , the government decided to introduce the new system from the usa , which was at first developed in order to correct distortions in reimbursement rates between medical practices some were over - valued while others were relatively under - valued4,6 ) . \n since the decision was made in the late 1990 s , to import the system from the usa , it took several years to determine the rvs for all physician services in korea before k - rbrvs was finally implemented in 2001 . \n the k - rbrvs , just like the rbrvs of the usa , determines relative fees of physicians practices on the basis of resource costs required to produce services : total work ( time and intensity ) of the physician , practice ( overhead ) costs and the opportunity costs regarding possible risks of professional negligence during medical practices4,5 ) ( fig . \n finally , the payment for a physician s practice is determined by multiplying the rv of each practice by a conversion factor , which converts the rv into korean won amounts ( fig . \n , it has undergone several minor revisions and one major revision in 2006 as a reflex of physicians or the government s requirements , and in order to reflex the actual change in costs as time flows . \n the system had a major revision on 2006 because , although the objective of the k - rbrvs was to correct the distortion in the structure of the medical fee system , there were still argument on fairness between medical practices of different specialties . \n this revised version of k - rbrvs was started in 2008 and remains in force until now . \n currently , the second major revision of k - rbrvs has been conducted , and is about to be implemented within this year . \n we have analyzed the change of spinal neurosurgical procedure rvs since it s first introduction in 2001 , and compared it with the change of values in the brain neurosurgical procedures . \n twenty - four procedures which were not on the list at 2001 , and those that have been added during annual revisions , were excluded from the analysis . \n overall average increase in rvs of each neurosurgical fields as well as that of increase in values of complex surgical procedures of both spinal and brain fields are shown on table 1 . while the overall increase rate of rvs of neurospinal surgeries was 62.8% since 2001 , that of brain surgeries was 92.3% , approximately 30% points larger . \n complex procedures in each groups were as following ; brain tumor surgeries , arterio - venous malformation surgeries , cerebrovascular aneurysm clipping or vascular bypass surgeries in brain neurosurgery , and vertebral / spinal cord neoplasm surgeries , corpectomy procedures or fusion operations in spinal neurosurgery . \n when comparing the change of rvs in these complex procedures between spinal neurosurgery and brain neurosurgery , the increase rate was 125.3% and 133% , respectively . \n the gap between each fields were smaller than that of the overall increase rate of rvs , however the increase rate of neurospinal practices was still smaller than that of brain surgeries . \n although the increase in rv reimbursement seems quite significant ( 62.8% ) in percentages during the past 15 years , when compared to the cumulative increase of consumer price announced by the korean national statistical office during the same period ( 61.9% ) it is hard to say that the increase is actually significant . and \n as already mentioned in the prior paragraph , when comparing the increase rate of rv with that of the brain neurosurgical procedures , the increase rate of spinal surgery rvs is even lower . on fig . \n 3 , the changes in rvs of some representative , index surgery procedures in both neurosurgical fields since 2001 , are shown as graph . when comparing complex surgical procedures such as tumor removal , we could find that the rvs have increased consistently since 2001 , in both brain and spinal neurosurgery . \n however , as the rvs of brain tumor surgeries were set at a higher amount of rv at first , the gap of rvs between brain tumor surgeries and spinal cord tumors are still present , resulting in a significantly higher rv for brain tumor surgeries ( fig . \n rvs of other brain surgical procedures such as vascular anastomosis procedures or aneurysm clipping surgeries have also increased in a high rate , more than 100% . \n considering more simple but frequently performed procedures , such as diagnostic or therapeutic craniotomies , the increase rate was 60100% which was relatively lower than complex surgeries ( fig . \n this rate was still a relatively high increase when compared with the frequent procedures performed in spinal neurosurgical field . \n complex decompression procedures such as vertebral corpectomy or fusion techniques such as anterior cervical fixation which has relatively high risk of complications showed increase rate of rvs similar to that of brain procedures . \n but at the same period of time , more commonly performed surgical procedures such as lumbar posterior fusion or lumbar laminectomy and discectomy showed almost no increase in rv for 15 years ( fig . \n considering the fact that the cumulative increase of consumer price during this period of time was over 60% , these results could mean that the actual rvs of these lumbar procedures have actually decreased . \n during the 1990 s , policy makers were concerned about the persistent growth of medical expenditures and at the same time they needed a standardized payment system regarding reimbursement for physicians . \n as a solution , the government decided to introduce the new system from the usa , which was at first developed in order to correct distortions in reimbursement rates between medical practices some were over - valued while others were relatively under - valued4,6 ) . \n since the decision was made in the late 1990 s , to import the system from the usa , it took several years to determine the rvs for all physician services in korea before k - rbrvs was finally implemented in 2001 . \n the k - rbrvs , just like the rbrvs of the usa , determines relative fees of physicians practices on the basis of resource costs required to produce services : total work ( time and intensity ) of the physician , practice ( overhead ) costs and the opportunity costs regarding possible risks of professional negligence during medical practices4,5 ) ( fig . \n finally , the payment for a physician s practice is determined by multiplying the rv of each practice by a conversion factor , which converts the rv into korean won amounts ( fig . \n , it has undergone several minor revisions and one major revision in 2006 as a reflex of physicians or the government s requirements , and in order to reflex the actual change in costs as time flows . \n the system had a major revision on 2006 because , although the objective of the k - rbrvs was to correct the distortion in the structure of the medical fee system , there were still argument on fairness between medical practices of different specialties . \n this revised version of k - rbrvs was started in 2008 and remains in force until now . \n currently , the second major revision of k - rbrvs has been conducted , and is about to be implemented within this year . \n we have analyzed the change of spinal neurosurgical procedure rvs since it s first introduction in 2001 , and compared it with the change of values in the brain neurosurgical procedures . \n twenty - four procedures which were not on the list at 2001 , and those that have been added during annual revisions , were excluded from the analysis . \n overall average increase in rvs of each neurosurgical fields as well as that of increase in values of complex surgical procedures of both spinal and brain fields are shown on table 1 . while the overall increase rate of rvs of neurospinal surgeries was 62.8% since 2001 , that of brain surgeries was 92.3% , approximately 30% points larger . \n complex procedures in each groups were as following ; brain tumor surgeries , arterio - venous malformation surgeries , cerebrovascular aneurysm clipping or vascular bypass surgeries in brain neurosurgery , and vertebral / spinal cord neoplasm surgeries , corpectomy procedures or fusion operations in spinal neurosurgery . \n when comparing the change of rvs in these complex procedures between spinal neurosurgery and brain neurosurgery , the increase rate was 125.3% and 133% , respectively . \n the gap between each fields were smaller than that of the overall increase rate of rvs , however the increase rate of neurospinal practices was still smaller than that of brain surgeries . \n although the increase in rv reimbursement seems quite significant ( 62.8% ) in percentages during the past 15 years , when compared to the cumulative increase of consumer price announced by the korean national statistical office during the same period ( 61.9% ) it is hard to say that the increase is actually significant . and \n as already mentioned in the prior paragraph , when comparing the increase rate of rv with that of the brain neurosurgical procedures , the increase rate of spinal surgery rvs is even lower . on fig . \n 3 , the changes in rvs of some representative , index surgery procedures in both neurosurgical fields since 2001 , are shown as graph . \n when comparing complex surgical procedures such as tumor removal , we could find that the rvs have increased consistently since 2001 , in both brain and spinal neurosurgery . \n however , as the rvs of brain tumor surgeries were set at a higher amount of rv at first , the gap of rvs between brain tumor surgeries and spinal cord tumors are still present , resulting in a significantly higher rv for brain tumor surgeries ( fig . \n rvs of other brain surgical procedures such as vascular anastomosis procedures or aneurysm clipping surgeries have also increased in a high rate , more than 100% . \n considering more simple but frequently performed procedures , such as diagnostic or therapeutic craniotomies , the increase rate was 60100% which was relatively lower than complex surgeries ( fig . \n this rate was still a relatively high increase when compared with the frequent procedures performed in spinal neurosurgical field . \n complex decompression procedures such as vertebral corpectomy or fusion techniques such as anterior cervical fixation which has relatively high risk of complications showed increase rate of rvs similar to that of brain procedures . \n but at the same period of time , more commonly performed surgical procedures such as lumbar posterior fusion or lumbar laminectomy and discectomy showed almost no increase in rv for 15 years ( fig . \n considering the fact that the cumulative increase of consumer price during this period of time was over 60% , these results could mean that the actual rvs of these lumbar procedures have actually decreased . \n in this study , in order to estimate whether we are reimbursed for surgical practices properly or not by the k - rbrvs , we have analyzed the rv of spinal neurosurgical practices under k - rbrvs . and also compared the results with that of brain neurosurgical practices . \n reimbursement to neurosurgeons , is categorized into three broad areas by the korean health insurance review & assessment service ( k - hias ) which is not different from that of the united states rbrvs7 ) . \n first , like all clinical specialties , diagnostic imaging studies as well as laboratory examinations provide revenue for neurosurgeons based on specific codes given by the k - hias . \n second , some minor outpatient department based simple procedures and some functional test or physical examinations have codes for reimbursement . \n third , as we are surgeons , we earn revenue by performing operations performed in hospital based operating rooms . \n while medical practices such as imaging studies or functional studies are the majority of practices in many non - surgical based specialties , the majority of reimbursement for neurosurgeons come from surgical procedures . \n 143 out of 159 ( 89.9% ) coded practices in the neurosurgical field are surgical procedures , and the total amount of money reimbursed for these surgical procedures were 112 billion korean won , 76.8% of the total amount of reimbursement in 20132 ) . as surgeons , reimbursement for surgical procedures are surely of most interest . in our study , we have found that the reimbursement for surgical procedures has been advantageous to brain surgeries than spinal surgeries . \n the gap of increase rates of rvs between two neurosurgical fields has been quite significant , as previously described ( table 1 ) . \n the korean neurosurgeons have a single large society , the korean neurosurgical society ( kns ) and both brain surgeons and spinal neurosurgeons are participating in this community . \n although majority of the members are actually engaged in the spinal neurosurgical field , many policy decisions have been made mainly by brain neurosurgeons for a long period of time . \n the chairman and president of this community has also been usually consisted of brain neurosurgeons much more often than spinal neurosurgeons . \n as brain neurosurgeons have played an active role in the society , policies related to the reimbursement for neurosurgical procedures might have also been mainly focused on brain surgeries , and spinal surgical procedures might have been relatively estranged from the main stream of policy interests . \n when comparing the actual increase of rvs in both neurosurgical fields between korea and usa , we could recognize how much the rvs of spinal procedures were estranged from proper increase . \n rvs of several frequently performed surgical procedures of both field in both nations are presented on table 2 . while the rv increase for such particular procedures were not so different between both fields in the usa , the increase rate was significantly higher for the brain procedures in korea \n another reason could be because of the unique circumstances of spinal surgical fields in korea . \n both neurosurgeons and orthopedic surgeons have their own society of spinal surgeons , and actually do not have an active academic exchange between societies . \n nonetheless , the k - rbrvs have a single system of rvs for spinal surgical procedures , regardless of the spinal surgeon s specialty . \n therefore , both societies should have closely collaborated and should have made united efforts in order to achieve adequate increase of rvs in the spinal surgical field , however they did nt for more than a decade \n . these complex circumstances probably resulted in a relatively low increase rate of rvs for spinal surgeries during the past 15 years . \n as mentioned previously , rvs for the procedures we perform are determined on the basis of resource costs required to produce services : total work ( time and intensity ) of the physician , practice ( overhead ) costs and the opportunity costs regarding possible risks of professional negligence during procedures4,5 ) . \n currently , the average proportion of physician s labor in total surgical practice rvs is 16%3 ) . \n after the second major revision in k - rbrvs , the overall average for percentage of physician s labor in rvs are supposed to be 26% for surgical procedures2 ) , which is much larger than before . \n but unfortunately , this trend of increase in the physician s labor does nt seem that it will be reflected in the neurosurgical field . \n the percentage of each costs planned for the second revision of k - rbrvs in representative neurosurgical procedural categories of both brain and spinal surgeries are shown on table 3 \n . the average percentage of physicians labor in rv will be 22.8% in brain surgeries while it will be only 18.0% in spinal surgeries2 ) . \n the opportunity cost representing possible risks of medical negligence is also lower in spinal surgical procedures than brain surgeries2 ) ( 10.5% vs. 6.3% ) . \n this result suggests that the k - hias estimates the spinal surgeons labor much lower than that of brain surgeons , and also estimates that opportunity costs for risk of spinal procedure related issues are also much smaller than brain surgeries . the physicians labor in brain neurosurgical procedures are lower than the average , and that of spinal neurosurgeries are even much more below the average . \n in the united states , the physician s labor takes 55% of the total rv1,6 ) which is much higher than that of k - rbrvs which is 18% currently3 ) ( fig . \n the physician s work is defined as the physician time and intensity involved in providing a surgical procedure , and it includes mental effort , physical effort , technical skills and psychologic stress involved in providing this surgical service6 ) . although we do not have objective measures for this currently , however there surely is doubt in whether we are adequately reimbursed for these efforts or not . \n especially more when we compare the proportion of physician s work with brain surgeons or that in the united states rbrvs . \n finally , our study has found that the reimbursement for spinal surgical procedures have been relatively underestimated for more than a decade under the k - rbrvs . when we analyzed the rvs of spinal surgeries , they were significantly smaller than that of brain surgeries and the increase rate for 15 years was smaller as well . \n another important point was that it was not only the overall rv of spinal surgeries that was underestimated , but also the proportion of surgeons labor . \n compared with that of united states rbrvs , the underestimation of a spinal physician s labor was even more significant . \n concerns that the rvs under rbrvs may not accurately reflect a surgeon s work , productivity or value is not surprising , and has already been an issue also in other surgical specialty societies8 ) . \n the problem is , that not much attention has been paid for this problem for a long period of time in our surgical society and maybe this lack of interest for proper reimbursement might have led to this discrimination of rvs . \n as the second major revision for k - rbrvs has already been done and is about to be under force within this year , it might be quite late to start any effort in order to fix this problem , and gain impartial reimbursement within a short period of time . \n however , it is surely better late than never , and effort trying to reduce the gap of increase in rvs between spinal surgeries and brain surgeries should be done as soon as possible . \n having regular policy meetings with the k - hias and effort to let them understand the current discrimination , and let them know our demands for proper reimbursement should be done . \n we should also show our effort in developing more objective measures of surgeon work to make the proportion of physician s work more adequate . and \n additionally , effort to collaborate closely with the orthopedic spinal surgeons to achieve this matters of mutual concern will be necessary as well . \n during the past 15 years , rvs for spinal neurosurgical procedures have increased in a rate of 62.8% , however this is hardly an actual increase when compared to the cumulative increase of consumer prices during this time period or the increase rate of 92.3% for brain surgeries . \n more effort of the society of spinal surgeons seems to be needed to get adequate reimbursement , as there have been some discrimination compared to brain surgeons in the increase of rvs . and \n considering the relative underestimation of spinal neurosurgeons labor , more objective measures of neurospinal surgeons work and productivity should be developed for impartial reimbursement .", "role": "user" }, { "content": "objectivesthe korean resource based relative value scale ( k - rbrvs ) was introduced in 2001 as an alternative of the previous medical fee schedule . \n unfortunately , most neurosurgeons are unfamiliar with the details of the k - rbrvs and how it affects the reimbursement rates for the surgical procedures we perform . \n we summarize the k - rbrvs in brief , and discuss on how the relative value ( rv ) of the spinal neurosurgical procedures have changed since the introduction in 2001.methodswe analyzed the change of spinal procedure rvs since 2001 , and compared it with the change of values in the brain neurosurgical procedures . \n rvs of 88 neurospinal procedures on the list of k - rbrvs were analyzed , while 24 procedures added during annual revisions were excluded.resultsduring the past 15 years , rvs for spinal procedures have increased 62.8% , which is not so different with the cumulative increase of consumer prices during this time period or the increase rate of 92.3% for brain surgeries . when comparing the change of rvs in more complex procedures between spinal and brain neurosurgery , the increase rate was 125.3% and 133% , respectively.conclusionmore effort of the society of spinal surgeons seems to be needed to get adequate reimbursement , as there have been some discrimination compared to brain surgeons in the increase of rvs . and considering the relative underestimation of spinal neurosurgeons labor , more objective measures of neurospinal surgeons work and productivity should be developed for impartial reimbursement .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: electroconvulsive therapy ( ect ) is one of the most efficacious treatment of major depressive disorder ( mdd ) . \n it is used as a rapid and efficacious treatment in emergent and/or treatment resistant forms of other psychiatric disorders . \n the cognitive aspects which are influenced immediately after ect are : orientation , information processing , retrograde and anterograde amnesia , visuospatial capacity and word finding . \n donepezil in a case report study galantamine in study without control group , a glucocorticoid antagonist ( cort108997 ) in another study , thyroid hormones , antihypertensive , poropofol , physosigmine , naloxone , piracetam showed some benefits in preventing ect - induced cognitive impairment ; but many of those have not enough reliability because were not statistically significant , or were case reports , unblanded , uncontrolled or on animals . \n the other studies did not show efficacy of the used drugs in prevention of memory impairments . considering these non sufficient and controversial data , more structured studies with control group on human samples are necessary . \n so , we chose the so - called memoral herbal for our this preventive new study , which has never been used for this propse . \n the memoral herbal capsules , each contains 360 mg of boswellia oleo - gum resin and 36 mg of zimgiber rhizome . the most important constituent of boswellia is gum resin 60% , mosilage 20 - 23% and essence 5 - 9% , which contains a - b - thujon , p - cymen and linanol . \n boswellia serrata has boswellic acid and acetyl- 11- keto - beta boswellic acid too , which are responsible for many therapeutic effect . \n the volatile oils in boswellia dilate the vasculator of the brain thus can increase the blood passage through the brain . \n boswellia extract has been demonstrated by a battery of rigorous tests to have anti - inflammatory effect . \n the mechanism by which boswellia can improve memory is through its anti - inflammatory effect on the brain . \n the aim of this study is to compare memoral herbal with placebo in prevention of ect - induced cognitive impairments . \n this study is a randomized and controlled clinical trial which was done during 9 months of 2011 at noor hospital ( isfahan , iran ) . \n the sample size was 70 patients , based on 80% power and 95% confidence interval . each consequent patient placed randomly in intervention ( memoral ) or control ( placebo ) group , i.e. , 35 patients in each group . \n the inclusion criteria were : 15 - 65ys / o , diagnosis of major depressive disorder ( mdd ) or bipolar disorder ( bd ) according to the impression of therapist ( academic member ) documented in the patient file , prescribed at least 4 ect sessions by the therapist and informed consent for participation . \n exclusion criteria were : mental retardation ( mr ) or dementia as documented in hospital file by psychiatrist , discontinuation of ect before fourth sessions , discontinuation of participation before the end of study , and arising delirium during the course of study . \n the ethical issues of this study was approved by ethical committee of behavioral sciences research center ( bsrc ) of isfahan university of medical sciences ( iums ) , iran . \n the study process registered at iranian registering of clinical trials office , with irct i d : irct201102072232n2 . \n the study was illustrated to patients and an informed consent form was signed by each patient or his / her first degree related person who was supporting him / her ( in cases the patient was unable to decide ) . \n each patient received three capsules ( tid ) of either memoral or placebo from the day before first ect session until 2 months after the last session of ect . \n memoral and placebo capsules were produced by goldaru pharmaceutical manufactory ( isfahan , iran ) . \n the capsules were labeled by only a or b brand and were taken to patients by a nurse . \n this scale was developed through extension of mini mental status examination ( mmse ) memory , language and visuospacial ability subscales , and adding verbal fluency subscale to it . \n it is translated to persian and validated by pouretemad h.r.(2006 ) . its sensitivity and specificity for screening normal persons from mild cognitive impairment ( mci ) is 93% and 91% , respectively ; for screening alzheimer patients from mci patients is 73% and 93% , respectively , and for screening normal persons from alzheimer patients is 100% and 96% , respectively . \n it has five subscales : attention and orientation , memory , language , verbal fluency , visuospatial ability . \n also it has the capacity for scoring based on the past so - called mmse scale . \n the patients cognitive function was assessed at four occasions : before the first ect session , before the 4 ect session , 1 month and 2 months after the last ect session , by a psychologist \n . the probable side effects of memoral were also evaluated at those occasions , using a checklist . \n the findings were analyzed by repeated measure of analysis of variance ( anova ) and pearson chi - square , using spss18 . \n this study is a randomized and controlled clinical trial which was done during 9 months of 2011 at noor hospital ( isfahan , iran ) . \n the sample size was 70 patients , based on 80% power and 95% confidence interval . each consequent patient placed randomly in intervention ( memoral ) or control ( placebo ) group , i.e. , 35 patients in each group . \n the inclusion criteria were : 15 - 65ys / o , diagnosis of major depressive disorder ( mdd ) or bipolar disorder ( bd ) according to the impression of therapist ( academic member ) documented in the patient file , prescribed at least 4 ect sessions by the therapist and informed consent for participation . \n exclusion criteria were : mental retardation ( mr ) or dementia as documented in hospital file by psychiatrist , discontinuation of ect before fourth sessions , discontinuation of participation before the end of study , and arising delirium during the course of study . \n the ethical issues of this study was approved by ethical committee of behavioral sciences research center ( bsrc ) of isfahan university of medical sciences ( iums ) , iran . \n the study process registered at iranian registering of clinical trials office , with irct i d : irct201102072232n2 . \n the study was illustrated to patients and an informed consent form was signed by each patient or his / her first degree related person who was supporting him / her ( in cases the patient was unable to decide ) . \n each patient received three capsules ( tid ) of either memoral or placebo from the day before first ect session until 2 months after the last session of ect . \n memoral and placebo capsules were produced by goldaru pharmaceutical manufactory ( isfahan , iran ) . \n the capsules were labeled by only a or b brand and were taken to patients by a nurse . \n this scale was developed through extension of mini mental status examination ( mmse ) memory , language and visuospacial ability subscales , and adding verbal fluency subscale to it . \n it is translated to persian and validated by pouretemad h.r.(2006 ) . its sensitivity and specificity for screening normal persons from mild cognitive impairment ( mci ) is 93% and 91% , respectively ; for screening alzheimer patients from mci patients is 73% and 93% , respectively , and for screening normal persons from alzheimer patients is 100% and 96% , respectively . \n it has five subscales : attention and orientation , memory , language , verbal fluency , visuospatial ability . \n also it has the capacity for scoring based on the past so - called mmse scale . \n the patients cognitive function was assessed at four occasions : before the first ect session , before the 4 ect session , 1 month and 2 months after the last ect session , by a psychologist \n . the probable side effects of memoral were also evaluated at those occasions , using a checklist . \n the findings were analyzed by repeated measure of analysis of variance ( anova ) and pearson chi - square , using spss18 . \n of 70 patients , two patients from memoral group and five patients from placebo group were excluded because of premature discontinuation of ect and discharge from the hospital , causing disruption of participation . \n so 33 patients in memoral group , and 30 patients in placebo group remained and there was not any significant difference between two groups ( p = 0.95 ) . considering educational levels , there was not any significant difference between two groups ( p = 0.18 ) : including 6 ( 9.5% ) patients had primary school studies , 23 ( 36.5% ) guidance school , 24 ( 38.1% ) high school , 10 ( 15.9% ) had university studies . \n the frequency of patients diagnosis was : 26 ( 41.3 ) patients with bd manic or mixed episode , 13 ( 20.6% ) patients bd depressive episode , 24 ( 38.1% ) patients with mdd . \n there was not any significant difference between memoral and placebo group about diagnoses distribution ( p = 0.09 ) . \n also there was no significant difference between the number of ect sessions in two groups ( pv=0.95% ) ; included 2 ( 3.2% ) patients received five ect sessions,25 ( 39.7% ) received six sessions , four ( 6.3% ) received seven sessions , 17 ( 26.9% ) received eight sessions , two ( 3.2% ) patients received nine sessions , 8 ( 12.7% ) received 10 sessions , two ( 3.2% ) patients received 11 sessions , two ( 3.2% ) patients received 12 sessions , and one ( 1.6% ) patient received 14 ect sessions . \n the mean energy of ect used in memoral group was 25.8 joule in memoral group , and 25.9 joule in placebo group ( p = 0.98).the mean age of patients in memoral group was 33.8 ys / o , and 32.8 ys / o in placebo group , with no significant difference between them ( p = 0.17).we did not find any important side effects that could exclude patients from the study , and there was not any significant difference between two groups for this issue ( p = 0.30 ) . \n there was not any significant difference between two groups between total score of ace of memoral group ( 76 ) and placebo group ( 79.4 ) before intervention ( p = 0.32 ) . \n also , there was not any significant difference between two groups for the scores of attention and orientation subscales ( p = 0.64 ) , memory ( p = 0.75 ) , verbal fluency ( pv = 0.35 ) , language ( p = 0.11 ) , and mmse subscales ( p = 0.40 ) before intervention . \n table 1 shows the mean sd of the total score of ace and the scores of ace subscales in memoral and placebo groups at four assessment occasions , i.e. , before intervention , before the 4 ect session , 1 month and 2 months after the last ect sessions [ figure 1 ] . \n the mean sd of the total score of ace and the scores of ace subscales in memoral and placebo groups at four assessment occasions : before intervention , before 4 ect session , 1 month and 2 months after last ect sessions the mean of the total score of ace in memoral and placebo groups at four assessment occasions : before intervention , before 4 ect session , 1month and 2months after last ect sessions repeated measure of anova showed that the total score of ace and the scores of attention and orientation subscale , memory , verbal fluency and mmse subscales were significantly higher in memoral group than in placebo group after intervention , and also were uprising , unlike placebo group [ table 1 , figure 2 ] . \n but the scores of the language , and visuospatial ability subscales did not show any significant difference between two groups , although these were uprising in memoral group , unlike in placebo group [ table 1 ] . \n the paired comparison of each subscales in two groups also showed significant difference at each stage . \n the mean of the memory subscale score of ace in memoral and placebo groups at four assessment occasions : before intervention , before 4 ect session , 1month and 2 months after last ect sessions \n this study assessed the efficacy of memoral herbal on prevention of ect - induced cognitive impairments , using ace scale . \n the total score of ace and the subscales of memory , attention and orientation , verbal fluency and mmse in memoral group were significantly higher than in placebo , and did not declined by ect unlike in placebo group . \n the noticeable finding was the largest amount of difference for memory subscale in this intervention [ table 1 , figure 2 ] . \n this study showed that memoral herbal prevents ect - induced memory impairment more rapidly and more impressively than other drugs used in previous similar studies.[313 ] unlike previous studies[313 ] in this intervention , we assessed cognitive status in more detailed and itemized description . \n so these data may have more reliability and scrupulosity than previous findings , and may somehow interpret the inconsistency of some previous findings.[1215 ] . \n the sample size of this study is another precedence of this study over previous ones . \n this was some deal because of the blinding goals and the independence of researchers from therapists . \n the future studies on prevention of ect - induced cognitive impairments may comprise memoral herbal with other drugs in a research , and on patients with other diagnoses . \n our work showed the effective prevention of ect - induct cognitive impairment by using memoral herbal . \n the memory , attention and orientation , verbal fluency , and mmse of patients showed improvement by memoral use .", "role": "user" }, { "content": "background : electroconvulsive therapy ( ect ) is one of the most efficacious treatment for major depressive disorder ( mdd ) , it is also used as a rapid and efficacious treatment for other psychiatric disorders , especially treatment resistant ones . \n the cognitive impairment is one of the most important side effects of ect . \n this study examined the memoral herbal efficacy in prevention of ect - induced memory impairment.methods:in a randomized clinical trial , 70 patients with mood disorders who were candidates for ect enrolled in either memoral or control group , and received either memoral or placebo . \n the memory was assessed by addenbrook cognitive examination ( ace ) , and the findings were analyzed by anova under spss18.results:the memoral group patients showed significantly higher total ace scores than placebo group ( p < 0.001 ) . \n the scores of attention and orientation , verbal fluency and memory subscales not only never decreased during the study in memoral group , but also increased . \n there was no significant difference between these scores of memoral and placebo groups for the subscales of language and visuospacial ability.conclusion:the memoral herbal is an efficacious and safe choice in prevention of ect- induced cognitive impairment .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: hepatic cysts are not uncommon , with reported incidences ranging from 3.5 to 10% [ 1 , 2 ] . \n cysts are typically classified as either congenital or acquired , with simple congenital cysts presenting more commonly in women and with increased age . \n simple hepatic cysts are most often asymptomatic and are discovered incidentally on abdominal ultrasound or abdominal computed tomography ( ct ) scans . \n when patients present with symptoms , they are usually secondary to the large size and subsequent mass effect on adjacent organs . treatment with aspiration has fallen out of favor due to a nearly 100% recurrence rate , and more evidence is emerging that laparoscopic fenestration is a safe and effective alternative to more invasive open procedures [ 1 , 2 ] . \n while multiple studies have shown the benefits of laparoscopic cyst management via fenestration , this procedure performed as a single - incision laparoscopic surgery ( sils ) is not well described in the literature [ 1 , 2 , 4 ] . \n the goal of this case study is to demonstrate the feasibility of performing this procedure as sils as well as its efficacy , safety and postoperative patient satisfaction . \n a 68-year - old female had a known hepatic cyst for about 3 years . it had been previously noted on abdominal ct but was not symptomatic at the time of discovery . upon developing gastroesophageal reflux - type symptoms , pressure - like abdominal pain , right upper quadrant pain , fullness and nausea , she was referred for surgical evaluation . \n physical exam was significant for palpable liver edge below the costal margin , but the abdomen was non - tender . \n this prompted further work - up , revealing elevated liver enzymes and a 16 cm 14 cm cystic hepatic lesion on magnetic resonance imaging ( mri ) , consistent with a simple cyst ( fig . 1 ) . \n an aspirate of the contents was obtained and sent for culture , gram stain , bilirubin , cea levels and ca-19 - 9 , all of which were within normal limits . owing to the patient 's discomfort , surgical fenestration and ablation of the remaining cyst wall were recommended . \n a single - incision laparoscopic approach was offered to the patient , and the patient consented to proceed . \n figure 1:coronal mri view of the giant hepatic cyst . \n the patient was taken to the operating room where a single incision through the fascia was made at the umbilicus and a sils port placed ( fig . 2 ) . \n the liver was thoroughly inspected , and the cyst was seen in liver segments 4 , 7 , 8 and superficially accessible over the caudate lobe . however , as the gallbladder was still in situ , this was not a viable location to unroof the cyst . \n the cyst was aspirated over segment 8 , and 1800 ml of clear aspirate was removed and sent for cytology and culture . in order to gain access to the cyst wall , a harmonic scalpel was used ; however , due to the cyst 's location , this required entering between a half centimeter and a centimeter of liver parenchyma . \n the anterior cyst wall was excised entirely , which involved removing a 12 8 cm segment . an argon beam and bovie coagulator \n diagnostic laparoscopy did not reveal any further areas of concern , the abdomen was irrigated and the sils port removed . \n the defect was closed using a 0 vicryl suture in a figure of eight fashion , twice . \n a modified wound vacuum - assisted closure dressing was placed with instructions to the patient to remove the dressing after 1 week . \n the patient was discharged home the same day , had no postoperative pain at her 2-week follow - up visit and reported resolution of her symptoms . \n it has been stated that sils is emerging as the latest advancement in minimally invasive surgery just as the laparoscopic technique was in 1988 . \n evidence is continuing to accumulate about the use of sils in commonly performed cases such as appendectomies , colectomies and cholecystectomies [ 68 ] . \n it is proved to be safe , effective and achievable with comparable blood loss and hospital stay when compared with the traditional laparoscopic technique . \n as sils only requires one port insertion through the umbilicus , closure of the incision allows the potential for scarless surgery , allowing for very cosmetically appealing results . \n additional studies have shown reductions in postoperative pain and reduced rates of herniation , reduced rates of wound infection and hematoma formation . continued research \n must be done to determine whether sils will one day prove beneficial enough to replace traditional laparoscopic technique . with the introduction of this new technique \n , surgeons must overcome a learning curve that can negatively affect operative times [ 7 , 8 , 10 ] . \n loss of triangulation , reduced view and less space for the surgeons ' hands to maneuver during operations are documented as potential difficulties with attempting the single - incision approach . \n when laparoscopy was first introduced , significant longer operative times were the norm when compared with the traditional open approach , but this was mitigated as surgeons gained familiarity and shared standardized approaches . with increased experience with the sils approach , standardization of technique and \n improved instrumentation , the challenges seen with this technique will likely be overcome as well . \n this case shows that our patient was able to undergo successful cyst fenestration via sils with a reasonable operative time and without excess difficulty or special instrumentation , thus demonstrating the flexibility of this technique . with sils , \n the overall postoperative cosmetic result is superior to the traditional laparoscopic technique , as is demonstrated by postoperative patient satisfaction questionnaires [ 79 ] . with congenital liver \n cysts occurring more commonly in women , improved cosmetic outcome when addressing symptoms surgically may be an important consideration for surgeons . \n sils continues to show promise and proves to be an exciting advancement in the innovative field of minimally invasive surgery . \n ", "role": "user" }, { "content": "large symptomatic hepatic cysts may warrant surgical management . \n traditional multiport laparoscopic technique is typically preferred over open laparotomy , but the use of the single - incision laparoscopic approach for this diagnosis is not well documented . here , we describe the case of a 68-year - old woman who underwent complete anterior wall fenestration , excision and cauterization of a simple hepatic cyst via a single - incision laparoscopic technique through an incision at the umbilicus . \n the objective of this case report is to document single - incision laparoscopy as a safe , feasible and cosmetically appealing approach for the management of a large hepatic cyst .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: tuberculosis ( tb ) is a main public health problem with high mortality and morbidity . \n between 19% and 43% of the world population is estimated to be infected with mycobacterium tuberculosis(1 ) . the world health organization ( who ) recorded 9.6 million new tb cases , of which 1.2 million ( 12% ) were also hiv positive , in 2014 . \n furthermore , 1.5 million deaths were confirmed as a consequence of the disease , including 400,000 deaths among hiv - positive patients ( 2 ) . \n tuberculosis new cases have resurgence due to the increase in co - morbidity with aids , the absence of proper treatment , the increased multi - resistant forms of tuberculosis and finally the relaxation of the disease control measures(3 ) . \n tuberculosis is the second most significant cause of death from infectious diseases among adults after aids . \n it bears a major cost for patients and their families as well as the public budgets(5 ) . \n in addition to that , tb is linked with a significant impact on quality of life , on labor productivity and on the society as a whole ( 5 ) . a 10% increase in the incidence of tuberculosis worldwide , \n will cause economic growth is to shrink by 0.2 - 0.4% , that is in absolute numbers a reduction of 1.4 - 2.8 billion usd per year(6 ) . \n a relationship has been observed between tuberculosis and migration of large population groups from countries with high incidence of the disease to low - incidence countries ( 3 , 7 , 8) . \n the proportion of active tb cases among the native - born population attributed to transmission from foreign born patients ranges from 2% to 17% ( 9 , 10 ) . \n tuberculosis in cyprus only concerns a tiny percentage of the population ; consequently the disease has a minimum effect on the overall public budget . on the other hand , \n more specifically , between 1997- 2012 , a total of 587 cases were reported , and 69.3% of them were immigrants . \n a potential outbreak of the disease would not only threaten the public health but also the economy ( 5 , 6 , 11 ) . \n the cyprus government partly recognizes the possible threat of tb transmission from immigrants to the native - born population . \n it is compulsory for all immigrants entering the country from countries not members of the european union to be tested for tb and other transmittable diseases ( such as hiv , hepatitis b and c and syphilis ) . on the other hand \n , immigrants coming from any european country can apply for legal permanent residence with no such requirement . in order to ensure complete control of the disease \n , cyprus government bears the overall costs of tb for all patients diagnosed with tuberculosis ( 12 ) . \n migration movement , in cyprus , was constantly rising until the year 2011 where the maximum number of immigrants was recorded ( 23,037 ) , just before the beginning of economic recession ( 13 ) . according to the population census of 2011 , \n the bulk of immigrants arriving for settlement in cyprus were from european union ( eu ) countries representing 55.6% of the total number . \n the highest number of immigrants came from greece ( 38.6% ) , followed by romania ( 26% ) , whereas philippines and sri lanka were the countries with the highest number of immigrants outside the eu ( 12.9% and 11.7% respectively ) ( 14 ) . \n the aim of this study is to assess whether screening all immigrants coming from countries ( including european union countries ) with high incidence of tuberculosis would be in the economic interest of the republic of cyprus or not . \n in order to assess whether it could be an beneficial for cyprus to expand the screening checks for tb , to all immigrants coming from high incidence countries a cost - benefit analysis ( cba ) was employed , and the net present value ( npv ) of the project was calculated . therefore , for the cost - benefit analysis that follows , the main assumption was to screen all immigrants coming from the european union countries that have high prevalence of tuberculosis ( namely bulgaria , romania and greece ) and not just immigrants from third countries and in the case of positive results to deny immediate entry into the republic of cyprus . \n the tb cost , as estimated for 2011 , amounts to 10,282 ( 15 ) . \n the analysis considers 2011 as the base year , therefore an assumption for the average annual inflation ( for the next 15 years ) of around 2% , is made based on historical data . \n the sensitivity of the mantoux test and chest x - ray is 85% ( 16 ) , while the mean annual increase in immigration from european countries is assumed 1% . the total number of immigrants from these countries in 2011 amount to 7,786 ( 13 ) . the mantoux test costs at market prices 23 while the chest x - ray costs 20 . \n an increase of incidence of tuberculosis of 7% is assumed , based on the historical data of 1997 2011 ( 12 ) . \n finally , the discount rate was determined according to the cyprus government proposal of 4% ( 17 ) . \n sensitivity analysis ascertains the degree to which the results of the quantified economic analysis such as the npv are sensitive to changes in the values of the key input parameters such as costs , incidence or length of implementation period . \n the npv is recalculated on the basis of different and less optimistic values for important variables . \n sensitivity analysis is always recommended when uncertainty exists ( 18 ) and the results of such analysis should always be reported and evaluated . \n cost benefit analysis studies include a number of assumptions and estimates , thus introducing a level of uncertainty ( 19 ) . \n consequently , it is of great significance , a sensitivity analysis to be conducted that considers alternative values for all important cost parameters and assumptions in the study . \n based on the above assumptions a cost benefit analysis was conducted according to the methodological guidelines of the cyprus government ( 17 ) . table 2 shows the base scenario for the cost benefit analysis . \n the analysis has a fifteen year length of implementation period and the base year ( year 0 ) was 2011 . \n based on a sensitivity of 85% ( 16 ) of the screening examinations the column true positives not detected record the patients that are expected to develop the disease although they successfully passed the diagnostic tests ( false negatives ) . \n the net present value was estimated at 3,188,653 which is greater than zero , so the expansion of screening diagnostic tests for tuberculosis to european citizens coming from countries with high prevalence will have a significant benefit to the cypriot economy and society . \n base scenario of cost benefit analysis according to the manual for pre - selection and appraisal of public investment projects ( 17 ) sensitivity analysis should include different scenarios for example increase of costs by 10% or decrease in revenues by 25% , etc . \n an absolute necessary condition however , is the inclusion of the best and worst case scenario . \n thus , a number of different what - if scenarios were formulated , each with different combinations of input values for key variables and/or assumptions . the above mentioned manual suggest for the best case scenario to assume a 25% increase in benefits ( which translates to 25% reduction of tb incidence in our case ) and a simultaneous reduction of costs of 25% . for the worst case scenario it suggests to assume simultaneous increase in costs of 25% and a decrease in benefits of 25% . in all \n what - if scenarios of the sensitivity analysis ( table 3 ) , the net present value is positive , therefore , there is a benefit to society if the provisions under consideration are implemented . in case of reduction of tb incidence by 25% and a simultaneous reduction of costs of 25% \n conversely , in case the costs increase as well as the incidence of the disease decrease by 25% , the npv is estimated at 6,688,569 . \n according to the manual for pre - selection and appraisal of public investment projects ( 17 ) sensitivity analysis should include different scenarios for example increase of costs by 10% or decrease in revenues by 25% , etc . \n an absolute necessary condition however , is the inclusion of the best and worst case scenario . \n thus , a number of different what - if scenarios were formulated , each with different combinations of input values for key variables and/or assumptions . the above mentioned manual suggest for the best case scenario to assume a 25% increase in benefits ( which translates to 25% reduction of tb incidence in our case ) and a simultaneous reduction of costs of 25% . for the worst case scenario it suggests to assume simultaneous increase in costs of 25% and a decrease in benefits of 25% . in all \n what - if scenarios of the sensitivity analysis ( table 3 ) , the net present value is positive , therefore , there is a benefit to society if the provisions under consideration are implemented . in case of reduction of tb incidence by 25% and a simultaneous reduction of costs of 25% \n conversely , in case the costs increase as well as the incidence of the disease decrease by 25% , the npv is estimated at 6,688,569 . \n to the best of our knowledge , this is the first study performed in cyprus that attempted to evaluate the economic benefits of a tb screening program . \n results of the study yield evidence that implementing a tuberculosis screening program for immigrants that are not currently tested prior to the settlement in cyprus , would decrease the incidence of tuberculosis , thus such a program would be a cost saving and a beneficial one for the society . \n the results of this study not only showed that the npv of this suggested strategy would have been positive ( 3,188,653 ) but also all different what - if scenarios had also positives npvs . implementing such a strategy could help towards the goal of the cyprus government to eliminate tuberculosis in its territory . \n movement of large population groups from countries with high tb prevalence in low tb prevalence countries has been associated with the increase of the incidence of tuberculosis in those countries ( 21 ) . \n consequently , in low tb prevalence countries , the foreign - born population constitutes a large proportion of reported cases of active tb , ranging from 3570% of all cases ( 21 ) . \n persons who migrate from countries with high tb prevalence , bear latent tuberculosis at the time of their migration , thus they are under an increased activation risk . as a result \n , they transmit the disease after a few years of their arrival in the host country . \n this period is estimated between 3 - 5 years ( 22 ) . according to world health organization \n , the incidence of tb among foreign born populations living in europe is estimated to be 50 times higher than that of native populations with a substantial economic impact of tb in low incidence countries ( 23 ) . \n positive about the screening control for tb are several studies in the literature . in a cost - benefit analysis study conducted in the united states of america in 2015 \n , it was reported that screening control of refugees from countries where tb prevalence is high , would yield a net present value of $ 4.9 million for a period of 20 years ( 24 ) . \n the same study estimated an npv of $ 1.6 million for a screening program for refugees from countries where tb prevalence is moderate . \n similarly , other studies have also aimed to examine whether screening migration may contribute to reducing tb cases , with positive results . \n more specifically , a study conducted in norway in 2010 showed that 88% of tb cases were detected in screening controls ( 25 ) . \n a survey in the netherlands showed that screening control of immigrants is economically viable ( 26 ) . \n finally , the united states preventive services task force recommends screening control all persons that were born in a country with high prevalence of tuberculosis ( 27 ) . as with all cost benefit analysis studies , this study also has limitations . \n the estimated cost of tuberculosis is based on only one study that included cyprus in their calculations . \n furthermore , assumptions were made for the sensitivity of the diagnostic tests , the inflation and the increase of the incidence of tb . \n however , these assumptions were based either on the literature or on historical data . on the other hand , \n the cost benefit analysis presents rough estimates and a general idea of whether testing immigrants for latent - tb would be cost beneficial for the society . \n our study concludes that testing all immigrants , including immigrants from high prevalence european countries that are not currently tested for tb , would be a cost - saving strategy to reduce the cost of treating tb in cyprus . \n given the rising importance of migration in europe , as thousands of refugees and immigrants cross the european borders for permanent residence , rigorous control measures should be decided among european countries to deal with the increasing costs of tb transmission in low prevalence countries .", "role": "user" }, { "content": "introduction : the study explored the potential economic benefit of an expanded screening program of immigrants before entrance to cyprus as a policy to reduce the overall cost of tuberculosis ( tb ) . \n thus , the aim of this study is to study whether screening all immigrants coming from countries ( including european union countries ) with high incidence of tuberculosis would be in the economic interest of the republic of cyprus or not.methods:in order to assess whether it could be economically beneficial for cyprus to expand the screening checks for tb to all immigrants coming from high prevalence countries , a cost - benefit analysis ( cba ) was employed , and the net present value ( npv ) of the project was calculated . in order to assess for uncertainty , \n sensitivity analysis using different scenarios , was conducted.results:the analysis has a fifteen year length of implementation period and the base year ( year 0 ) was 2011 . \n the npv was estimated at 3,188,653 which is greater than zero ; therefore , the expansion of screening diagnostic tests for tb to european citizens coming from countries with high prevalence of tb will have a significant benefit to the cypriot economy and society . \n this result is also supported by the fact that all what - if scenarios of the sensitivity analysis yielded a positive npv.conclusion:our study concludes that testing all immigrants , including immigrants from high prevalence european countries that are not currently tested for tb , would be a cost - saving strategy to reduce the cost of treating tb in cyprus .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: cushing disease is one of the most demanding entities to diagnose and treat ( 1 ) . \n however , radiographic visualization of a pituitary \n microadenoma associated with cushing disease is sometimes difficult on standard 1.5 tesla \n ( 1.5 t ) magnetic resonance imaging ( mri ) ( 2 ) . for \n patients with cushing disease in whom standard mri \n does not reveal a pituitary microadenoma \n with certainty , ips ( inferior petrosal sinus ) or cs ( cavernous sinus ) sampling may be \n performed in order to distinguish the central source from ectopic acth secretion and to \n localize the suspected corticotroph microadenoma to one side of the pituitary ( 3 ) . however , venous sampling of the pituitary is \n asymmetric , and its potential for inaccuracy is well documented ( 4 ) . \n currently , high - field mri scanners operating at 3 tesla ( 3 t ) are \n entering routine clinical use and are becoming available from most manufacturers . \n they can \n offer improved quality and spatial resolution in conditions with subtle differences between \n normal and abnormal tissue ( 5 , 6 ) . \n we \n were unable to locate the patient s pituitary microadenoma on 1.5 t mri , although venous \n sampling was positive for the presence of a tumor . \n however , 3 t mri of the brain , which was \n performed 3 mo later , clearly demonstrated a microadenoma in the left side of the pituitary \n gland . \n herein , we describe \n the diagnostic usefulness of 3 t mri of the brain for cushing disease in a child . \n the patient , an 11-yr - old girl , was admitted to our university hospital because of low \n height velocity with body weight gain . \n sudden body weight gain had been noted for 3 yr prior to admission , and a \n decrease in height velocity had been noticed beginning at 9 yr of age . \n her most recent \n height growth rate was only 2.5 cm / yr . on admission , she had a body temperature of 36.8c , \n blood pressure of 120/66 mmhg and heart rate of 60/min . \n her height and weight were 131.1 cm \n ( 1.88 sd ) and 37.3 kg ( body mass index : 21.6 kg / m , 90th percentile ) , \n respectively . \n bone age was 10.1 yr by the tanner - whitehouse ( tw2 ) \n method standardized for japanese children . \n endocrinological examinations revealed hypercortisolism ( serum cortisol level of 21.235.0 \n g / dl , urinary free cortisol ( ufc ) level of 326.0492.0 g / d ) with no diurnal variation of \n serum cortisol levels . \n a crh test revealed a normal basal acth level and elevated basal \n cortisol level with positive responses to crh stimulation . \n high - dose dexamethasone \n suppressed 24-h ufc collection from 492.0 g / d to 115.0 g / d ( table 1 ) . \n in the radiological findings , abdominal ct revealed \n swelling of the bilateral adrenal glands , but 1.5 t mri of the brain by spgr ( spoiled \n gradient recalled echo ) demonstrated no microadenomas in the pituitary gland ( fig . \n the superiority of 3 \n tesla mri in comparison with 1.5 tesla mri in the detection of microadenoma is \n demonstrated . ) . \n subsequent ips and cs sampling revealed a remarkable step - up of plasma acth in the \n left side and of serum prl levels in both sides of the gland ( table 2 ) . \n the peripheral serum prl level was elevated to 33.4 \n ng / ml . table 1 endocrinological studiescircadian rhythm of the pituitary - adrenal \n axistime ( h)8:0016:0024:00acth ( pg / ml)45.255.038.4cortisol ( g / dl)26.521.222.1crh testtime ( min)pre15306090120acth ( pg / ml)32.1118.098.142.028.227.2cortisol ( g / dl)35.053.550.944.435.229.3dexamethasone suppression testdose of dexamethasone30 g / kg / d120 g / kg / dpreday1day2day3day4day5u - cortisol ( g / d)492.0460.0328.0195.0115.0u-17-ohcs ( mg / d)10.117.211.517.110.1u-17-ks ( mg / d)8.113.112.324.013.5acth ( pg / ml)24.132.823.6cortisol ( g / dl)24.418.117.5 \n table 2 ips and cs sampling datart \n ipsperipheralacth ( pg / ml)31.426.13,270.021.8c / p ratio1.441.20150prl ( ng / ml)347.0676.81,089.033.4gh ( ng / ml)7.2713.017.100.23cs : cavernous sinus , : not done . \n ips : inferior petrosal sinus . \n 3 tesla and 1.5 tesla brain mri images by the spgr method . \n the superiority of 3 \n tesla mri in comparison with 1.5 tesla mri in the detection of microadenoma is \n demonstrated . \n however , we \n selected adrenal - directed therapy instead of neurosurgery for our patient because no \n microadenomas were detected in her pituitary gland . \n oral administration of metyrapone ( 750 \n mg / d ) was started after her discharge . \n her plasma cortisol levels decreased to between 12 \n g / dl and 16 g / dl . \n three months later , 3 t mri of the brain using the spgr method was \n carried out to detect pituitary microadenoma . as shown in fig . \n 1b , coronal t1-weighted images with gadolinium clearly demonstrated a 3-mm \n less - enhanced lesion in the left side of her pituitary gland . \n ultimately , transsphenoidal \n surgery was performed , and a 3.5-mm microadenoma was totally resected from the left side \n ( fig . \n ( c ) \n acth immunohistochemistry by using anti - human acth ( x50 , dako ) and a benchmark system \n ( ventana ) . \n ( h & e ) staining of the microadenoma , diffuse \n proliferation of slightly large and basophilic cells was found ( fig . \n immunohistochemical examinations demonstrated that the \n microadenoma stained positively for only acth ( fig . \n 2c ) . \n consequently , the diagnosis of \n an acth - secreting microadenoma was confirmed , and a mixed tumor with acth- and prl - positive \n cells was excluded . \n follow - up 3 t mri revealed no relapse of microadenoma in her pituitary gland . pathological findings . \n ( c ) \n acth immunohistochemistry by using anti - human acth ( x50 , dako ) and a benchmark system \n ( ventana ) . \n acth - secreting microadenomas are visible on 1.5 t mr images in 3663% of cases in patients \n with cushing disease ( 7 ) . therefore \n , proving that the \n source of acth secretion is from the pituitary gland is not a simple process . \n recently , 3 t \n mri has entered clinical use in some university hospitals in japan . compared with 1.5 t mri , \n 3 \n t mri offers the advantage of a higher signal - to - noise ratio ( snr ) , which provides higher \n resolution and proper image quality within an acceptable scanning time ( 8 , 9 ) . \n pinker \n et al . reported that 3 t mri was superior to 1 or 1.5 t mri for predicting \n the invasion of adjacent structures in patients with pituitary adenomas and that it improves \n surgical planning of sellar lesions ( 3 ) . \n some studies \n have shown that 3 t mri might ameliorate the imaging difficulties associated with \n acth - secreting pituitary adenomas ( 2 , 9 ) . \n in particular , high - field mr imaging by the spgr \n method can detect very small but hormonally active sellar lesions such as microadenomas . in our patient , \n a 3-mm less - enhanced lesion was clearly identified in the left side of the \n anterior pituitary by 3 t mri of the brain using the spgr method . \n figures 1a and 1b \n demonstrate the superiority of 3 t mri in comparison with 1.5 t mri in the detection of \n microadenoma in our case , although these pictures were not taken simultaneously . \n on the \n other hand , it has been reported in another study that 3 t mri failed to determine the site \n of the microadenoma in some patients with cushing disease ( 2 ) . \n therefore , to identify a pituitary microadenoma in cushing disease more \n correctly , both 3 t mri of the brain and venous sampling will be necessary in addition to \n endocrinological examinations . \n it is also interesting that our case featured markedly elevated prl levels in venous \n sampling of the pituitary gland , but did not have a separate prolactinoma . \n her \n hyperprolactinemia improved after operation . in the series of 11 adult patients reported by \n caufriez et al . , 10 of whom had preoperative elevation of morning prl \n levels , serum prl normalized after transsphenoidal surgery as in our case ( 10 ) . on assessing menstrual abnormalities in cushing \n disease , lado - abeal et al . \n found mildly elevated serum prl levels in 20% of \n female patients , although the serum prl and menstrual abnormalities were not correlated \n ( 11 ) . \n yamaji et al . also indicated \n preoperative prl elevation in 23% of japanese patients with cushing disease ( 12 ) . \n elevated preoperative prl levels in cushing disease \n are still of unproven diagnostic significance ( 13 ) . \n however , we need to consider the complications of hyperprolactinemia even for cushing \n disease in children . in summary , \n 3 t mri is a very useful tool for localizing microadenomas and is necessary to \n evaluate the prognosis for cushing disease in children as well as in adults . \n it will be the \n first choice of radiological examinations in suspected cases of cushing disease .", "role": "user" }, { "content": "it is sometimes difficult to confirm the location of a microadenoma in cushing disease . \n recently , we experienced an 11-yr - old female case of cushing disease with \n hyperprolactinemia . \n she was referred to our hospital because of decrease of height \n velocity with body weight gain . on admission , she had typical symptoms of cushing \n syndrome . although no pituitary microadenomas were detected on 1.5 tesla mri of the brain , \n endocrinological examinations including ips and cs sampling were consistent with cushing \n disease with hyperprolactinemia . \n oral administration of methyrapone instead of \n neurosurgery was started after discharge , but subsequent 3 tesla mri of the brain clearly \n demonstrated a 3-mm less - enhanced lesion in the left side of the pituitary gland . \n finally , \n transsphenoidal surgery was performed , and a 3.5-mm left - sided microadenoma was resected . \n compared with 1.5 tesla mri , 3 tesla mri offers the advantage of a higher signal to noise \n ratio ( snr ) , which provides higher resolution and proper image quality . \n therefore , 3 tesla \n mri is a very useful tool to localize microadenomas in cushing disease in children as well \n as in adults . \n it will be the first choice of radiological examinations in suspected cases \n of cushing disease .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: clostridium difficile , a gram - positive and spore - forming anaerobic bacillus , is a leading cause of healthcare - associated diarrhoea in industrialized countries . \n transmission occurs primarily in healthcare facilities , where exposure to antibiotics and environmental contamination by c. difficile spores are common . \n antibiotic treatment , advanced age ( > 65 years ) , comorbidities and hospitalization have been identified as major risk factors for c. difficile infection ( cdi ) . however , antimicrobial therapy is the single most important risk factor for cdi . \n it leads to the disruption of the normal intestinal flora , creating favourable conditions for acquisition and proliferation of c. difficile \n . \n clindamycin , amoxicillin , third - generation cephalosporins and more recently fluoroquinolones have been shown to be associated with a particularly high risk of developing cdi . \n the first whole genome sequence of c. difficile was obtained in 2006 ; sequencing revealed a large circular chromosome of 4 290 252 bp likely coding for 3776 proteins and an extracircular plasmid 7881 bp in size . \n these studies have shown that the c. difficile genome contains a high proportion ( over 10% ) of mobile genetic elements including bacteriophages , repeat elements and genomic islands , as well as transposable and conjugative elements . \n several typing methods have been used to study the epidemiology , genetic diversity and evolution of c. difficile . in europe pcr ribotyping \n has been one of the most widely adopted methods , and over 600 c. difficile ribotypes have been identified . \n a particular subtype , c. difficile ribotype 027 , has been associated with severe disease and hospital outbreaks in north america and europe , , . \n global emergence of this moxifloxacin - resistant c. difficile type 027 prompted establishment of national surveillance programs in several european countries , , . \n as a result of national surveillance , a clonal aggregation of a newly emerging , moxifloxacin - resistant c. difficile ribotype 231 ( rt231 ) was uncovered in sweden in 2008 . \n this type was initially geographically limited to the stockholm area , where over 70% of all moxifloxacin - resistant c. difficile strains were characterized as rt231 in 2008 ( 125/144 ) . despite an increasing awareness of cdi and enhanced infection control policies , rt231 has continued to spread in sweden ; by the end of the year 2015 it had been identified in 13 of 21 counties , suggesting interhospital transmission and possible local outbreaks . although no studies have shown whether moxifloxacin use implies higher risk for cdi than other commonly used antibiotics , the restriction of moxifloxacin use has been associated with a reduction in the number of cdis in northern ireland and england , . \n similarly , a study from vienna demonstrated that enhanced antibiotic stewardship , including restriction of moxifloxacin use , was associated with a reduction in the number of cdi in population with a high rate of multidrug - resistant c. difficile \n . \n we used whole genome sequencing ( wgs ) and phylogenetic analysis to investigate the spread of this newly emerging moxifloxacin - resistant c. difficile rt231 in sweden between 2006 and 2015 . \n we also evaluated the potential association between the extent of moxifloxacin prescription rates and the epidemiology of rt231 . \n all 189 c. difficile rt231 isolates identified in sweden between 2006 and 2015 were included in this study ( table 1 ) . \n the strains collected between 2009 and 2015 were obtained through the national surveillance program for c. difficile ; before 2009 samples were obtained via a nationwide surveillance study . \n pcr ribotyping between 2006 and 2012 was performed by a gel - based method and between 2013 and 2015 by capillary - gel electrophoresis . \n all moxifloxacin - sensitive strains were included , and moxifloxacin - resistant isolates were selected to cover each isolation region per year to obtain a geographically and temporally representative sample collection . \n isolates were grown on mueller - hinton fastidious agar , and minimum inhibitory concentration ( mic ) values for moxifloxacin , erythromycin , clindamycin , metronidazole and vancomycin were determined using etests ( biomrieux , marcy letoile , france ) as described previously . \n the epidemiologic cutoff breakpoints for resistance were as follows : metronidazole mic > 2 mg / l , vancomycin mic > 2 mg / l , erythromycin mic > 2 mg / l , clindamycin mic > 16 mg / l and moxifloxacin mic > 4 mg / l , according to the european committee on antimicrobial susceptibility testing ( eucast ) . \n isolates were recultured on blood agar plates , inoculated into sterile peptone yeast liquid medium with 0.5 mg / ml cysteine and grown overnight anaerobically at 35c . \n cells were pelleted , suspended into lysis buffer ( 1 mm tris , 0.1 mm edta , 0.1% triton - x and 20 mg / ml lysozyme ) with proteinase k ( 180 l of buffer and 20 l of proteinase k ( 20 l / ml ) ) and incubated for 18 hours at 56c . \n genomic dna was extracted using magattract dna mini m48 kit and biorobot m48 according to the manufacturer 's recommendations ( qiagen , sollentuna , sweden ) . \n wgs was performed using the ion torrent platform , aiming to read lengths of 200 bp and coverage of 30. the sequence data were analysed by clc assembly cell 4.4.2 software . \n sequence type ( st ) was determined for comparison using mapping and the basic local alignment search tool ( blast ) against the c. difficile multilocus sequence typing ( mlst ) database ( http://pubmlst.org/cdifficile/ ) . \n strain mx213 was used as the reference genome for single nucleotide polymorphism ( snp ) analysis . \n positions with low coverage ( < 10 ) or ambiguous calls ( < 90% ) in one or more samples were filtered out . \n snps within 500 bp of each other were filtered out as single events from the snps in the phylogenetic analysis to remove nonrandomly distributed mutations ; these are collectively termed recombination events . \n the analysis was repeated excluding the four nonrelated strains ; the remaining individual snp positions were compiled into an alignment and used for phylogenetic analysis . \n neighbour - joining phylogenetic trees were constructed on the basis of the snp alignments using mega 6.0 and 100 bootstrap replicates . \n the genomic relatedness of isolates was assessed by snp analysis : up to three individual snps per genome was expected to be seen between related isolates collected up to 1 year apart , whereas strains which differed more than ten individual snps were classified as unrelated . \n data on moxifloxacin prescriptions were obtained from apotekens service ab ( 20032013 ) and from the swedish ehealth agency ( 20142015 ) . \n the data include moxifloxacin prescribed to patients as well as sales to hospitals and other healthcare providers . \n a total of 51 of 189 c. difficile rt231 isolates selected for wgs were geographically and temporally representative ; they included isolates from all 13 counties where rt231 strains had been isolated over a 10-year period ( table 1 , table 2 ) . \n an average minimum coverage of 60.07 ( range 20.52120.13 ) reads per nucleotide and an average genome length of 4.14 ( range 3.924.30 ) mbp were obtained for all samples . \n no previous wgs data were available for c. difficile rt231 , and thus the first whole genome sequence of rt231 was obtained by a de novo assembly of strain mox213 ( 3.92 mbp ) . \n mlst data obtained from whole genome sequence representing approximately 0.09% of the whole genome ( 3501 nt ) were almost consistent with ribotyping data ; all studied isolates belonged to st133 . \n one isolate ( nt949 ) , determined to be pcr rt231 by a gel - based method , belonged to st133 , but pcr ribotyping analysis by capillary - gel electrophoresis with higher resolution suggested a new , unknown ribotype . \n a total of 4091 nucleotide differences were identified within the 51 isolates ; 3225 nucleotide differences were classified as recombination events , whereas the remaining 866 nucleotide differences were classed as individual snps . \n the results are presented in a minimal spanning tree in fig . 1 ( 88.56% of the genome was used as the dynamic core genome ) . \n a total of 3496 nucleotide differences distinguished four single isolates ( three moxifloxacin - sensitive isolates nt049/jnkping_2009 , nt513/vstragtaland_2010 and nt1619/skne_2012 and one moxifloxacin - resistant isolate nt949/norrbotten_2011 ) from the remaining 47 isolates ( all moxifloxacin - resistant isolates ) . \n a total of 2681 nucleotide differences out of 3496 were filtered as 447 recombination events . within the remaining 47 isolates , five strains ( mx405/stockholm_2008 , mx381/stockholm_2008 , nt422/gotland_2009 , nt116/stockholm_2009 and nt099/stockholm_2009 ) differed by 554 nucleotides from the closest main cluster of 42 isolates . \n a total of 544 nucleotide differences out of 554 were filtered as three recombination events . in order to study potential transmission of moxifloxacin - resistant c. difficile rt231 between different counties during the 10-year study period , \n a phylogenetic comparison of 47 strains based on the core genome snp analysis was performed ( excluding the unrelated isolates nt049 , nt513 , nt949 and nt1619 ) . \n a total of 93.2% of the genome was used in the analysis as the dynamic core genome . \n a total of 566 nucleotide differences were identified , of which 510 were classified as recombination events . \n seventeen isolates collected between 2007 and 2012 in the counties of stockholm , uppsala and blekinge formed the first cluster , with only 3 snps ' difference between them ( cluster 1 , fig . 2 ) . \n a clonal strain ( defined as 1 snp difference ) was identified in five different hospitals in the counties of stockholm and uppsala during 2008 and 2009 . \n the remaining stockholm isolates from 2008 and 2009 ( n = 4 ; all from the same hospital ) formed their own bootstrap supported cluster together with a single isolate identified in gotland during the same time period ( cluster 2 , fig . 2 ) . \n the third cluster was composed of the oldest isolate identified in stockholm in 2006 , another stockholm isolate from 2008 and all the other isolates collected in uppsala ( n = 7 ) , vstmanland ( n \n = 5 ) , sdermanland ( n = 8) , rebro ( n = 2 ) and dalarna ( n = 1 ) , with a maximum difference of 3 snps between the isolates ( cluster 3 , fig . 2 ) . \n a second clonal strain was circulating in the counties of uppsala , sdermanland , vstmanland and rebro between 2009 and 2015 . in total , 48 of the 51 c. difficile rt231 isolates were resistant to moxifloxacin according to eucast epidemiologic cutoff mic breakpoints . \n all moxifloxacin - resistant c. difficile rt231 isolates identified between 2009 and 2015 were also resistant to clindamycin and erythromycin . \n all moxifloxacin - resistant strains harboured an amino acid substitution in the gyra gene ( thr82 > ile ) ; the unrelated moxifloxacin - resistant nt949 strain had an additional amino acid substitution in the gyrb gene ( asp426 > asn ) . \n we screened the isolates for the presence of the ermb gene known to confer macrolide and lincosamide resistance . \n interestingly all isolates carried most of the tn5398 transposon with a deletion of the ermb locus ( fig . \n all isolates were also negative for the other predominant erm genes found in anaerobes ( a , c , e , f and q ) . \n both sensitive and resistant strains carried the cme gene , which encodes an efflux pump similar to mefa , shown to confer erythromycin resistance . \n furthermore , the 23s rrna sequences were analysed , but no differences were found between sensitive and resistant strains . a mutation in the rpld gene ( g211a , ala71 > thr ) , encoding the l4 protein of the 50s ribosomal subunit , was found in 25 of 47 resistant isolates , with all isolates belonging to cluster 3 . \n all five isolates in cluster 2 , on the other hand , carried a mutation in the rplv gene ( g313a , val105 > ile ) encoding the l22 protein of the 50s ribosomal subunit . to evaluate a possible link between moxifloxacin consumption and the spread of rt231 , we analysed the county - specific consumption rates for moxifloxacin \n . the mean community prescription rate of moxifloxacin in sweden decreased from 9.2 defined daily doses ( ddd ) per 1000 inhabitants per year in 2003 to 4.46 in 2015 , whereas the mean hospital prescription rates increased from 1.17 ddd per 1000 inhabitants per year in 2003 to 2.59 in 2015 . \n the differences in the community moxifloxacin prescription between counties became smaller over time ( range in community 0.2423.26 ( 2003 ) and 0.5411.53 ( 2014 ) ddd per 1000 inhabitants per year ) , whereas the opposite was seen in the hospital prescription rates between counties ( range in hospital 0.133.25 ( 2003 ) and 0.189.13 ( 2014 ) ddd per 1000 inhabitants per year ) . in 2014 the highest prescription rates , both in community and hospital settings , were identified in uppsala county ( 11.53 and 9.13 ddd per 1000 inhabitants per year , respectively ) ( fig . \n hospital use of moxifloxacin was also high in sdermanland county in 2014 ( 9.02 ddd per 1000 inhabitants per year ) . \n two other counties , jnkping and kronoberg , were noted also to have had high overall prescription rates of moxifloxacin in both community and hospital settings . \n we investigated the emergence and epidemiology of moxifloxacin - resistant c. difficile rt231 in sweden between 2006 and 2015 by wgs and compared the geographical spread of this moxifloxacin - resistant type to county - specific moxifloxacin prescription rates . \n a majority of rt231 isolates identified in sweden since 2006 have been moxifloxacin resistant ( 98% , 186/189 ) . \n the proportion of moxifloxacin resistance among all c. difficile isolates has been around 15% in sweden between 2009 and 2015 ( range , 1021% ) , which is less than previously reported : 40% in europe . \n the amino acid substitution ( thr82 > ile in gyra gene ) is the most frequently described mutation associated with fluoroquinolone - resistant c. difficile , including the hypervirulent ribotype 027 ; it was also present in all moxifloxacin - resistant rt231 isolates studied . \n although association between multiple substitutions and high - level moxifloxacin resistance have been previously demonstrated , all resistant isolates of rt231 included in our study harboured only a single mutation and showed high - level resistance ( mic > 32 \n interestingly , most of the tn5398 transposon was detected , but with a deletion of the ermb gene locus , known to confer macrolide and lincosamide resistance . \n macrolide and lincosamide resistance is thus most likely conferred by an as - yet unknown mechanism . \n although isolates belonging to clusters 2 and 3 carried mutations in the l4 or l22 proteins of the 50s ribosomal subunit \n proteins associated with macrolide resistance , the closely related isolates in cluster 1 have l4 and l22 proteins identical to the erythromycin - sensitive strains , and we believe that an evolution of separate resistance mechanisms is unlikely . \n although c. difficile rt231 was first identified in a stockholm hospital as early as in 1999 , it remained a rare type until the outbreak was identified in stockholm county in 2008 , . on the basis of the previously estimated evolutionary rate of 0.74 snp per year for c. difficile , \n up to 3 snps per genome would be expected to be seen between related isolates collected up to 365 days apart . by using these previous estimates of c. difficile evolution \n , we concluded that the first two rt231 strains are likely related and originated from a common ancestor . \n these isolates were isolated almost by a 2-year gap in stockholm ( cd901 , cluster 2 ; mx3 , cluster 1 ) and harbour 6 snp differences in between . \n in contrast , two genetically distinct c. difficile genotypes were also shown to be circulating in stockholm in 2008 , as demonstrated by more than 10 snps ' difference between the isolates ( mx70 and mx381 ) . \n interestingly , a third genetically distinct c. difficile genotype ( mx165 ) differing from mx70 by five nucleotides was also identified in stockholm during the same year . \n this shows that at least two divergent sublineages of moxifloxacin - resistant c. difficile rt231 were already circulating in the stockholm area when the outbreak was found in 2008 , and other strains related to these outbreak strains had likely been circulating in the area years before that . \n the continued circulation of a clonal strain , demonstrated both in the stockholm and uppsala rebro healthcare regions , suggests that rt231 strains can persist for a long time in healthcare settings . \n because the spread of clonal strains ( defined as 1 snp difference ) occurred mainly within a healthcare region , patient movement through hospitals with specialized care is presumably the main transmission route for spreading c. difficile rt231 . \n it is therefore important to implement strict cleaning procedures and isolation routines for all patients infected with moxifloxacin - resistant strains to stop further transmission . \n spread of rt231 was noted in stockholm county in 2008 , but the emergence had likely already occurred few years before that . \n it is unclear why it emerged particularly in the stockholm area , where the prescription rate of moxifloxacin has not been the highest in sweden . \n however , it is important to note that the reduced use of moxifloxacin in stockholm county has coincided with a reduction in the spread of rt231 in the area and the increased moxifloxacin use in uppsala county with the increased spread of this moxifloxacin - resistant type . \n similarly , the counties of jnkping and kronoberg , which had high prescription rates of moxifloxacin between 2005 and 2010 , were affected by outbreaks of moxifloxacin - resistant c. difficile other than rt231 : rt046 and rt027 respectively , . in the county of jnkping , as prescription rates dropped and infection control was implemented , rt046 has virtually been eliminated from the area . \n interestingly , in a case control study in stockholm county , fluoroquinolones were identified as a statistically significant risk factor for acquiring rt231 cdi , but only a small proportion of individuals infected with this strain had actually received moxifloxacin ( zomer et al . , unpublished data ) . \n this is keeping with the idea that general antibiotic pressure in the community plays a major role in driving the emergence of resistant strains of c. difficile , and , as in the case of moxifloxacin - resistant rt231 , further use of any fluoroquinolone will likely lead to cdi problems in infected individuals . \n a qualitative goal for limiting fluoroquinolone prescribing in outpatient care in sweden was set in 2007 , but none of the counties has reached the target set ( https://www.folkhalsomyndigheten.se/pagefiles/24127/swedres-svarm-2015-15099.pdf ) . a limitation of this study is the lack of information regarding the number of cases and patient hospitalizations ( i.e. a move to another hospital ) . \n this study may also contain multiple isolates from the same individuals , so the real number of cases can not be determined . \n in addition , because routine surveillance was established in sweden in 2009 , isolates collected before 2009 were not systematically collected . as a further limitation , \n age - specific moxifloxacin and general fluoroquinolone consumption rates were unavailable for study . in conclusion , we used snp analysis based on wgs to investigate the emergence and spread of moxifloxacin - resistant c. difficile rt231 in sweden over a 10-year study period . \n we demonstrated the continued transmission of rt231 within and between different close - proximity counties . \n the outbreak emerged first in the stockholm area and spread to surrounding counties in the uppsala rebro healthcare region . \n our results support the need for careful monitoring of hospitalized individuals infected with moxifloxacin - resistant c. difficile types as well as for stricter limits on fluoroquinolone prescriptions in sweden . \n although rt231 has only been described in sweden so far , it can potentially spread to countries where other moxifloxacin - resistant c. difficile types have also recently emerged . \n the factors associated with the emergence of new ribotypes within a certain country remain largely unexplored .", "role": "user" }, { "content": "an aggregation of moxifloxacin - resistant clostridium difficile ribotype 231 ( rt231 ) isolates was first identified in the county of stockholm in 2008 , and by the end of 2015 isolates of rt231 had spread to 13 of 21 swedish counties . \n we investigated the epidemiology of c. difficile rt231 in sweden between 2006 and 2015 using whole genome sequencing ( wgs ) and evaluated whether its emergence could be associated with extended moxifloxacin use . \n we performed wgs and phylogenetic analysis of 51 c. difficile rt231 strains isolated in sweden over a 10-year period . \n we also calculated the county - specific prescription rates for moxifloxacin between 2005 and 2015 . \n using wgs and detailed single nucleotide polymorphism analysis , we demonstrated three divergent sublineages of moxifloxacin - resistant c. difficile rt231 in sweden from 2008 to 2015 . \n a set of closely related rt231 was identified in hospitals located in the counties of stockholm and uppsala in 2008 . \n another set of rt231 isolates was found in four different counties in the uppsala rebro health care region . \n a gradual drop in moxifloxacin use in the county of stockholm coincided with a reduction of rt231 in the area . \n however , rt231 continued to be frequent in surrounding counties including uppsala , a county that also had the highest moxifloxacin prescription rates . \n we demonstrated frequent transmission of c. difficile rt231 within and between counties , indicating the importance of careful monitoring of hospitalized individuals infected with moxifloxacin - resistant c. difficile as well as the need for a strict moxifloxacin prescription policy .", "role": "assistant" } ]

[ { "content": "You are a medical writer. Summarize the following article: worry is conventionally studied within the anxiety disorders , but it has recently been given prominence in a theoretical account of persecutory delusions ( freeman , 2007 ) . \n worry brings more implausible paranoid ideas to mind , keeps them there , and escalates the distress . \n there is increasing evidence to support this view . in a national epidemiological survey , individuals reporting concerns of plots to harm them had almost ten times higher odds of reporting worry than individuals without paranoid fears ( freeman et al . , 2011 ) . \n cross - sectional studies with patients with persecutory delusions have shown that high levels of worry are common , comparable to those seen in generalised anxiety disorder , and that higher levels of worry are associated with more distressing paranoia ( freeman and garety , 1999 ; freeman et al . , 2001 ; startup et al . , 2007 ; morrison and wells , 2007 ; bassett et al . , 2009 ; freeman et al . , 2010 ) . \n longitudinal studies have shown that worry predicts the later development and persistence of paranoid fears ( startup et al . , 2007 ; freeman et al . \n , 2012b ) , and an experimental study has shown that higher levels of worry predict the occurrence of paranoid thoughts ( freeman et al . , 2008 ) . \n in the strongest tests of the causal role of worry in persecutory delusions , two clinical intervention studies have shown that directly targeting the cognitive style of worry significantly lessens paranoia ( foster et al . , 2010 ; hepworth et al . , \n this series of studies indicates that worry in psychosis may well require the level of attention it receives in the anxiety disorders . \n theoretical accounts of psychosis increasingly highlight both affective and cognitive routes to delusions ( e.g. garety et al . , 2001 ; myin - germeys et al . , \n this is not meant to imply that affect has no cognitive mechanisms but to make the distinction between what have traditionally been considered as emotional and psychotic processes . \n non - affective cognitive disturbance in psychosis has had the greater focus ( e.g. hemsley , 1993 ; frith , 1992 ; kapur , 2003 ; green et al . , 2004 ) , but the emotional route to delusions is gaining evidential support ( e.g. lincoln et al . \n the study of worry in psychosis is an example of the latter affective route , since worry is traditionally considered central to the experience of anxiety problems and it is not listed in descriptions of psychosis , but is there an impact of worry on cognitive processes traditionally associated with psychosis ? \n is there an interaction between emotional and psychotic processes ? to answer this question we examined the immediate effects of a bout of worrying on three processes studied in psychosis : working memory , jumping to conclusions , and perceptual anomalies . \n meta - analyses have consistently shown that working memory performance is impaired in individuals with a diagnosis of schizophrenia ( e.g. lee and park , 2005 ; forbes et al . , 2009 ) , leading to the view that it may be an endophenotype for the diagnosis ( e.g. horan et al . , 2008 ) . jumping to conclusions , a tendency to seek less data before reaching a decision , \n has been specifically linked with delusional beliefs , and it has been reliably found in patients with psychosis ( see garety et al . , 2007 ; freeman , 2007 ; fine et al . , 2007 ) . \n particular cognitive dysfunctions in psychosis are considered to produce anomalies of experience ( such as perceptual and attentional disturbances , altered experience of self , aberrant salience ) that lead to delusional misinterpretations ( e.g. maher , 1988 ; kapur , 2003 ; uhlhaas and mishara , 2007 ) ; the presence of such anomalies have been repeatedly found in patients with psychosis ( e.g. chapman , 1966 ; phillipson and harris , 1985 ; bunney et al . , 1999 ; parnas et al . , 2003 ) and to be associated with delusional ideation ( e.g. bell et al . , 2006 ; \n we therefore studied worry in relation to three processes commonly considered important cognitive markers of psychosis . \n study of a bout of worry in patients with psychosis has not been reported before . however \n , a bout of worry in non - clinical worriers has been found to be associated with a reduction in working memory capacity ( hayes et al . , 2008 ; leigh and hirsch , 2011 ) , and an anxious mood induction has been found to increase the jumping to conclusions bias in a non - clinical sample ( lincoln et al . , 2010a ) , although not in a delusions group ( so et al . , 2008 ) . whether a mood induction increases perceptual anomalies is unknown , but levels of anxiety positively correlate with the presence of perceptual distortions ( e.g. bell et al . , 2011 ; tone et al . , 2011 ) . \n in the current study it was hypothesized that psychotic processes would be exacerbated when patients engage in a period of worry : that worry makes it harder to process information and reason and that it creates a more subjectively odd state . \n it was predicted that a decrease in working memory , an exacerbation of the jumping to conclusions reasoning style , and the occurrence of anomalous experiences would be greatest in a worry induction group and least in a worry reduction condition . in order to enhance the clinical relevance of the study \n , we chose to study a bout of worry in patients with persecutory delusions in which worry was identified as at a high level ; the effects of worry were studied in those who were prone to adopt this cognitive style . \n 67 patients with persecutory delusions completed the study during the baseline assessment , prior to randomisation , of a clinical trial ( isrctn23197625 ) ( freeman et al . , 2012a ) . \n the participants were recruited from two mental health nhs trusts : oxford health nhs foundation trust , southern health nhs foundation trust . \n the inclusion criteria were : a current persecutory delusion as defined by freeman and garety ( 2000 ) ; scoring at least 3 on the conviction scale of the psyrats delusions scale ( i.e. at least 50% conviction in the delusion ) ( haddock et al . , 1999 ) ; that the delusion had persisted for at least three months ; a clinical diagnosis of schizophrenia , schizoaffective disorder or delusional disorder ; a clinically significant level of worry , as indicated by scores above 44 on the penn state worry questionnaire ( see startup and erickson , 2006 ) ; aged between 18 and 65 ; and no changes to medication in the past month . \n criteria for exclusion were : a primary diagnosis of alcohol or substance dependency or personality disorder ; organic syndrome or learning disability ; a command of spoken english inadequate for engaging in therapy ; and currently having individual cbt . the psyrats delusions is a six item multidimensional measure . \n higher scores indicate greater severity . the panss is a 30-item rating instrument developed for the assessment of patients with schizophrenia . \n part a assesses ideas of reference ( e.g. it was hard to stop thinking about people talking about me behind my back ) and part b assesses ideas of persecution ( e.g. i was convinced there was a conspiracy against me ) . each item is rated on a 5-point scale . \n the pswq is the most established measure of trait worry style and has been used in non - clinical and clinical populations ( see review by startup and erickson , 2006 ) . \n the vocabulary and matrix reasoning subtests were used to obtain an estimate of iq . in order to test the effects of the three conditions on worry and mood state , \n the participants marked on three 0 ( not at all ) to 100 ( totally ) visual analogue scales the degree to which \n three working memory tasks were used : digit span forwards , digit span backwards , and letter number sequencing . \n these are the most commonly used working memory tasks in schizophrenia research ( see nuechterlein et al . , 2004 ) . \n data - gathering was assessed with a probabilistic reasoning task that has been extensively used with people with delusions . \n participants are asked to request as many pieces of evidence ( coloured beads ) as they would like before making a decision ( from which of two hidden jars the beads are drawn ) . \n the colours of the beads in the jars were altered for the repeat of the task . \n the key variable is the number of beads requested before making a decision . in the current study \n the caps was adapted into a state measure by asking whether any of the perceptual anomalies had occurred in the past 5 min , with participants simply responding with a yes or no . \n the scale covers a variety of anomalies including changes in levels of sensory intensity ( e.g. are sounds much louder than they normally would be? ) , distortion of own body or the external world ( e.g. have you found the appearance of things or people seeming to change in a puzzling way e.g. distorted shapes or sizes or colour? ) , sensory flooding ( e.g. have you found that sensations happened all at once and flooded you with information? ) , temporal lobe experiences ( e.g. have you had the feeling that of being uplifted , as if driving or rolling over a road while sitting quietly? ) and hallucinations ( e.g. have you heard noises or sounds when there was nothing about to explain them? ) . in the current study we analysed the total score , but also tested separately the hallucination items and the non - hallucination perceptual anomalies . \n the cds was based on the view that depersonalisation constitutes a syndrome which , in addition to ineffable feelings of \n unreality , also includes emotional numbing , heightened self - observation , changes in body experience , distortions in the experiencing of time and space , changes in the feeling of agency , feelings of having the mind empty of thoughts , memories and/or images , and an inability to focus and sustain attention ( sierra and berrios , 2000 ) . \n two studies have shown that the scale assesses five distinct types of anomalous experiences ( sierra et al . , 2005 ; simeon et al . , 2008 ) . \n we used an adapted state version by asking about the occurrence of such experiences in the past few minutes . \n we used 19 items from the cds , since ten items were not suitable for a state version ( e.g. previously familiar places look unfamiliar , as if i had never seen them before ) . \n we examined the total score but also used four factors from the largest study of the cds structure ( simeon et al . \n , 2008 ) : unreality of self ( e.g. familiar voices ( including my own ) sound remote and unreal ) , perceptual alterations ( e.g. i have the feeling that my hands or my feet have become larger or smaller ) , unreality of surroundings ( e.g. what i see looks \n lifeless , as if i were looking at a picture ) , and temporal disintegration ( e.g. it seems as if things that i have done had taken place a long time ago. ) . \n participants completed the baseline assessments and the tasks assessing working memory , jumping to conclusions , and anomalous experiences . \n they then either received a worry induction , worry reduction , or a neutral condition . \n the worry induction procedure was designed to encourage worry about topics that each participant already spent considerable time thinking about . \n it consisted of three stages . in the first stage the worry domains questionnaire ( wdq ; tallis et al . , 1992 ) \n was used to elicit common worries ( that are not paranoid ) . in the second stage \n , participants took their two main worries identified from the wdq and completed the catastrophising procedure for each ( vasey and borkovec , 1992 ) . \n the catastrophising procedure produces a worry chain by the experimenter repeatedly responding to answers with \n what is it that worries you about x? participants were led to produce at least ten catastrophising steps for each worry . \n the third stage was 5 min of further engagement with worry , using instructions from mclaughlin et al . \n ( 2007 ) : during this period we would like you to engage with your worrisome thoughts \n . please refer to your list of worrisome topics . when you are asked to begin , \n please close your eyes and worry about your most worrisome topic in the way that you usually worry about it , but as intensely as you can , until the experimenter asks you to stop and open your eyes . \n if you normally worry about one topic at a time , please try to do the same during this period . \n however , if your thoughts change to another worry topic during this period feel free to allow these thoughts to continue . \n it is alright to change topics during this period if the changes occur naturally during the worry process . we have previously shown in non - clinical individuals that worry is increased using this procedure ( southgate , 2009 ) . \n the worry reduction procedure consisted of a 10 min mindfulness relaxation exercise ( mindfulness of the breath ) ( kabat - zinn , 2006 ) , which could be accompanied by positive music if the participant chose ( delibes : copplia act 1 number 3 mazurka ) ( mayer et al . , 1995 ) . the neutral condition consisted of the person simply reading from a selection of magazines for ten minutes . participants who received the worry induction condition also received if they wished the worry reduction condition at the end of testing . \n all analyses were carried out using spss version 20 ( ibm , 2011 ) . to test change after the randomisation condition , analysis of covariance was used , with post - randomisation score as the dependent variable , group as a fixed factor , and baseline score as the covariate . \n when there was a main effect of group , least significant difference pairwise comparisons for the estimated marginal means were tested . \n basic demographic and clinical information for each of the randomisation groups is presented in table 1 . \n the participants predominately had clinical diagnoses of schizophrenia , were unemployed , and were prescribed anti - psychotic medication . \n they had levels of paranoia as assessed by the gpts comparable to other studies of patients with persecutory delusions ( e.g. freeman et al . , 2010 ) and levels of worry as assessed by the pswq comparable to patients with generalised anxiety disorder ( e.g. behar et al . , 2003 ) . \n it can be seen in table 2 that the worry induction condition significantly increased levels of worry compared with the other two conditions . \n the worry induction condition also produced an increase in anxiety and a decrease in happiness compared with the other two conditions . \n the post - randomisation performance of each group on the tasks assessing psychotic processes is summarized in table 3 . \n it can be seen that there are no differences between the groups in performance on working memory or jumping to conclusions tasks ( controlling for baseline scores ) . \n however there are increases in the occurrence of anomalies of experience in the worry induction condition compared with the other two conditions . \n the only exception for anomalous experiences is that the occurrence of hallucinations is not affected by randomisation condition . \n ( the same significant effects are found if panss total score is added as a covariate . ) \n previous research has shown that this is the most common presentation of paranoia ( e.g. freeman and garety , 1999 ; morrison and wells , 2007 ; freeman et al . , 2010 ) . \n we examined the effects of a bout of worry in these individuals on processes customarily considered as markers of psychosis . \n given that worry was known to occur frequently in these patients we wanted to know whether it impacted on psychotic processes . \n the occurrence of worry did not affect working memory or jumping to conclusions , but it did lead to an increase in a range of low - level anomalous experiences . \n increases in sensations of the unreality of self and surroundings ( e.g. feeling of being a detached observer ) , perceptual alterations ( e.g. body feeling very light as it if were floating ) , and temporal disintegration ( e.g. seeming as if things done recently had taken place a long time ago ) were all more likely to occur after a period of worry . \n worrying less reduced the occurrence of anomalies of sensory intensity ( e.g. lights or colours seeming brighter or more intense than usual ) and sensory flooding ( e.g. difficulty distinguishing one sensation from another ) . \n our assessment covered a wide variety of anomalous experiences and it was only the occurrence of hallucinations that was unaffected . \n the point of interest learned from the experiment is that a period of worry in these patients was creating a range of potentially confusing and puzzling perceptual experiences that are known to predict paranoid thoughts . \n this is an illustration of an interaction of affective with psychotic processes , and adds to our understanding of how worry may contribute to delusional experience . \n this information can be incorporated into the emerging therapies that target worry in psychosis ( foster et al . \n 2011 ) ; clinicians can assess for and normalise the occurrence of such anomalies after a period of worry in patients with persecutory delusions . \n this fails to replicate the finding of worry impeding working memory in high non - clinical worriers ( e.g. leigh and hirsch , 2011 ) . \n however these previous studies assessed working memory and worry concurrently , while in the current study we simply assessed the effects after a period of encouraging worry . \n we do not know the extent to which individuals in the worry induction condition were continuing to worry , which is a limitation of the study . \n it is also clear that the worry induction was having effects more generally on mood ; this is to be expected but limits the precision with which the occurrence of anomalous experiences can be attributed specifically to worry . \n previous studies have had mixed findings on jumping to conclusions when manipulating levels of anxiety ( so et al . , 2008 ; \n , 2010a ) , and the current study does not support the idea that jtc changes with anxious mood state . \n we examined three key processes and did not alter significance levels for multiple testing , agreeing with the view that simply describing what tests of significance have been performed , and why , is generally the best method of dealing with multiple comparisons ( perneger , 1998 ) . \n the final key limitation is that we did not assess levels of paranoia before and after each randomisation condition which means that we could not test whether and how paranoia increased after worrying ; we simply tested the effects of worry on psychotic processes , and a larger experimental study that can examine mediation is now warranted ( emsley et al . , 2010 ) . \n our contention is that the role of worry will receive increasing attention in the study and treatment of delusions . \n the study was supported by a grant ( 09/160/06 ) from the efficacy and mechanism evaluation ( eme ) programme , which is funded by the uk medical research council and uk nhs national institute for health research . \n the study was designed by daniel freeman , helen startup , graham dunn and david kingdon . \n ", "role": "user" }, { "content": "worry has traditionally been considered in the study of common emotional disorders such as anxiety and depression , but recent studies indicate that worry may be a causal factor in the occurrence and persistence of persecutory delusions . \n the effect of worry on processes traditionally associated with psychosis has not been tested . \n the aim of the study was to examine the short - term effects of a bout of worry on three cognitive processes typically considered markers of psychosis : working memory , jumping to conclusions , and anomalous internal experience . \n sixty - seven patients with persecutory delusions in the context of a non - affective psychotic disorder were randomised to a worry induction , a worry reduction , or a neutral control condition . \n they completed tests of the cognitive processes before and after the randomisation condition . \n the worry induction procedure led to a significant increase in worry . \n the induction of worry did not affect working memory or jumping to conclusions , but it did increase a range of mild anomalous experiences including feelings of unreality , perceptual alterations , and temporal disintegration . \n worry did not affect the occurrence of hallucinations . \n the study shows that a period of worry causes a range of subtle odd perceptual disturbances that are known to increase the likelihood of delusions . \n it demonstrates an interaction between affective and psychotic processes in patients with delusions .", "role": "assistant" } ]