shukoor65/lab-rag-model huggingface dataset:
Effect of weight loss on upper airway collapsibility in obstructive sleep apnea. Previous investigators have demonstrated in patients with obstructive sleep apnea that weight reduction results in a decrease in apnea severity. Although the mechanism for this decrease is not clear, we hypothesize that decreases in upper airway collapsibility account for decreases in apnea severity with weight loss. To determine whether weight loss causes decreases in collapsibility, we measured the upper airway critical pressure (Pcrit) before and after a 17.4 +/- 3.4% (mean +/- SD) reduction in body mass index in 13 patients with obstructive sleep apnea. Thirteen weight-stable control subjects matched for age, body mass index, gender (all men), and non-REM disordered breathing rate (DBR) also were studied before and after usual care intervention. During non-REM sleep, maximal inspiratory airflow was measured by varying the level of nasal pressure and Pcrit was determined by the level of nasal pressure below which maximal inspiratory airflow ceased. In the weight loss group, a significant decrease in DBR from 83.3 +/- 31.0 to 32.5 +/- 35.9 episodes/h and in Pcrit from 3.1 +/- 4.2 to -2.4 +/- 4.4 cm H2O (p less than 0.00001) was demonstrated. Moreover, decreases in Pcrit were associated with nearly complete elimination of apnea in each patient whose Pcrit fell below -4 cm H2O. In contrast, no significant change in DBR and a minimal reduction in Pcrit from 5.2 +/- 2.3 to 4.2 +/- 1.8 cm H2O (p = 0.031) was observed in the "usual care" group. We conclude that (1) weight loss is associated with decreases in upper airway collapsibility in obstructive sleep apnea, and that (2) the resolution of sleep apnea depends on the absolute level to which Pcrit falls.
Cavernomas of the central nervous system: clinical and neuroimaging manifestations in 47 patients. Forty seven cases of central nervous system cavernous angioma (21 males and 26 females) are described. The main clinical signs were epilepsy and brainstem syndromes. Digital subtraction intra-arterial angiography, when used, failed to reveal cavernoma. CT detected many of the lesions, but the most successful supplementary diagnostic procedure was MRI which produces highly characteristic images of cavernous angioma. The diagnosis of cavernous angioma was confirmed in the 18 cases in which the tumour was removed surgically.
Upper airway collapsibility in snorers and in patients with obstructive hypopnea and apnea. During sleep, mild reduction in inspiratory airflow is associated with snoring, whereas obstructive hypopneas and apneas are associated with more marked reductions in airflow. We determined whether the degree of inspiratory airflow reduction was associated with differences in the collapsibility of the upper airway during sleep. Upper airway collapsibility was defined by the critical pressure (Pcrit) derived from the relationship between maximal inspiratory airflow and nasal pressure. In 10 asymptomatic snorers, six patients with obstructive hypopneas, and 10 patients with obstructive apneas, during nonrapid eye movement sleep, Pcrit ranged from -6.5 +/- 2.7 cm H2O to -1.6 +/- 1.4 and 2.5 +/- 1.5 cm H2O, respectively (mean +/- SD, p less than 0.001). Moreover, higher levels of Pcrit were associated with lower levels of maximal inspiratory airflow during tidal breathing during sleep (p less than 0.005). We conclude that differences in upper airway collapsibility distinguish among groups of normal subjects who snore and patients with periodic hypopneas and apneas. Moreover, the findings suggest that small differences in collapsibility (Pcrit) along a continuum are associated with reduced airflow and altered changes in pattern of breathing.
Adhesiolysis. Lysis of adhesions improves pregnancy rates. Results of laparoscopic lysis are not different from those of laparotomy. Since laparoscopy is more convenient to the patient, less expensive, saves hospital beds, and involves low morbidity, it should be the preferred surgical approach to the diagnosis and treatment of pelvic adhesions whenever possible. The use of a sharp dissection combined with electrocautery seems, at this time, to be equally effective to the use of lasers of different kinds. Adjuvants presently available, especially Hyskon or INTERCEED, have an added benefit to surgery alone. Even with the best surgical technique, adhesions tend to re-form. Although SLL will identify the extent of adhesion re-formation, the therapeutic advantage of lysing re-formed adhesions is yet to be proved.
Coronary artery stenting after angioplasty with self-expanding parallel wire metallic stents. Parallel wire stents were implanted over exchange guide wires at percutaneous transluminal coronary angioplasty sites in 27 canine coronary arteries that were predilated with slightly oversized balloons. Stents were stainless steel, self-expandable, 3.5 to 4.5 mm in diameter, 9 to 12 mm in length, and were made of 10 wires that were longitudinally laser-welded in a zig-zag design. The compressible stent was delivered by the withdrawal of a Teflon outer catheter (4.2 to 4.9F) and the push of a polyethylene inner catheter. Aspirin, 80 mg per day, was given from the day before the study began, and heparin (150 U/kg) was administered during implantation. Quantitative angiography and pathologic examinations were performed at day 0 and at weeks 2, 4, 12, 26 and 52. The coronary angiographic diameter at the stent site immediately after stenting marginally increased from diameter before stenting: 3.22 +/- 0.40 mm versus 3.14 +/- 0.37 mm (p = 0.03), and during a mean of 14 weeks of follow-up, remained unaltered from immediate post-stenting: 3.29 +/- 0.43 mm versus 3.22 +/- 0.40 mm (p = NS) with no stent displacement. Comparisons of patency and thrombosis between heparin-coated and uncoated stents, between left anterior descending and circumflex arteries, and among the three different diameters of stents showed uniformly good results. At microscopy, the wires were oriented perfectly and embedded in the arterial wall, and by 2 weeks they were covered by mucopolysaccharide ground substance, smooth muscle cells, and an almost complete monolayer of neoendothelial cells.
Eight-year outcome in infants with birth weight of 500 to 999 grams: continuing regional study of 1979 and 1980 births. Victorian Infant Collaborative Study Group. The outcome at a mean age of 8.3 years was determined for 88 of 89 surviving children with birth weights of 500 to 999 gm who were born in Victoria in 1979 and 1980; the condition of the untraced child, severely disabled at 5 years of age, was assumed to be unchanged at 8 years. Principal impairments in the children at 8 years of age were cerebral palsy 8 (9%); bilateral blindness 6 (6.7%) and poor vision in another 4 (4.5%); bilateral deafness requiring amplification 5 (5.6%); and epilepsy 2 (2.2%). The Full Scale score of the Weschler Intelligence Scales for Children--Revised was available for 77 children: 5 scores (6.5%) were less than 71 (low IQ), and 9 (11.7%) were between 71 and 85 (borderline IQ). Severe disability in 16 children (18%) was due to severe cerebral palsy, bilateral blindness, or low IQ. Mild or moderate disability was present in another 18 children (20.2%) with borderline IQ, mild or moderate cerebral palsy, poor vision, deafness, or epilepsy. Significantly more outborn children (10/18, 55.6%) than inborn children (24/71, 33.8%) were disabled. Ten children required special schooling; reading accuracy or comprehension was at least 18 months behind chronologic age in 17 (23%) of 75 children in normal school who were tested. The 2-year assessment correctly estimated the category of disability at 8 years of age in 55 (62%), overestimated it in 24 (27%), and underestimated it in 10 (11%). For the 82 children also seen at 5 years age, the category of disability at 8 years of age was correctly identified in 69 children (84%), overestimated in 4 (5%), and underestimated in 9 (11%). Change in psychologic test scores was the principal reason for reclassifying children. We conclude that the 2-yar assessment was valuable in the early identification of most of the severely disabled children, but developmental delay at 2 years of age did not always portend intellectual impairment at 8 years of age.
Sun protection in childhood. There is compelling evidence that childhood is a particularly vulnerable time for the photocarcinogenic effects of sun exposure on the skin. Studies indicate that excessive sun exposure during the first 10-20 years of life greatly increases the risk of skin cancer. Nonmelanoma skin cancer (basal cell and squamous cell carcinoma) has been associated with cumulative sun exposure, whereas melanoma has been associated with short, intense sun exposure or blistering sunburn. Under normal circumstances, children receive three times the annual sun exposure of adults; most of one's lifetime sun exposure occurs in childhood. Depletion of the earth's protective ozone layer adds to the photodamage problem. It is clear that sun protection is most vital in the early years. Those with fair skin are at highest risk. Photoprotective measures including sunscreen, clothing, and sun avoidance in childhood may significantly reduce the occurrence of melanoma and other skin cancer in later life. Regular use of sunscreen with a sun protection factor of 15 during the first 18 years of life could reduce the lifetime incidence of nonmelanoma skin cancer by 78%. Pediatricians can play a major role in educating parents and children.
Sacrospinous fixation--should this be performed at the time of vaginal hysterectomy? A sensible individualized approach should be applied to every patient undergoing transvaginal surgery for benign disease. This approach should attempt to correct every defect present in the pelvic supports. Uterovaginal prolapse is the result rather than the cause of genital prolapse. Not every vaginal hysterectomy should be treated like a cystocele-rectocele repair. Instead, every defect of the endopelvic fascial support should be evaluated in a patient both before and during surgery. As a result of these evaluations, more than just a hysterectomy and an anterior and posterior colporrhaphy may be performed. In a case in which a patient is found to have more than one defect at the time of examination, sacrospinous fixation of the vaginal apex at the time of transvaginal hysterectomy may be indicated. In the office, the patient can be examined in the supine and standing positions, both with and without Valsalva's maneuver, to determine if moderate to severe uterovaginal prolapse exists. Sacrospinous fixation should be performed in those cases as an adjunct to other steps taken to prevent postthysterectomy prolapse.
Animal models for arterial thrombolysis and prevention of reocclusion. Erythrocyte-rich versus platelet-rich thrombus. Experimental animal models for erythrocyte-rich (ER) and platelet-rich (PR) arterial thrombosis were developed in dogs and rabbits and used for the evaluation of the effect of antithrombin and antiplatelet agents on thrombolysis with recombinant tissue-type plasminogen activators (rt-PA). The canine models consist of a whole blood clot produced in the left anterior descending coronary artery (ER thrombus) or a 1-cm everted (inside-out) segment graft in the circumflex coronary artery that predisposes to occlusion with PR material (PR thrombus). The rabbit models consist of a femoral arterial whole blood clot (ER thrombus) or a femoral arterial eversion graft (PR thrombus). The whole blood clot models are sensitive to recanalization with rt-PA but are consistently associated with reocclusion, notwithstanding the concomitant use of heparin and/or aspirin. Clot lysis is accelerated and reocclusion is prevented by the administration of F(ab')2 fragments of a monoclonal antibody 7E3 directed against the platelet glycoprotein IIb/IIIa receptor; of Argatroban, a synthetic thrombin inhibitor; or of kistrin, a glycoprotein IIb/IIIa-blocking polypeptide from the Malayan pit viper venom. The PR thrombus models are very resistant to recanalization with rt-PA, but this resistance can be overcome by the concomitant use of the platelet glycoprotein IIb/IIIa-blocking antibody. Thus, selective platelet glycoprotein IIb/IIIa inhibitors are more effective than aspirin, heparin, or both in accelerating arterial thrombolysis with rt-PA; in preventing reocclusion after clot lysis; and in overcoming the resistance of PR thrombus to dispersion with rt-PA. These experimental animal models may be useful in the development of improved thrombolytic strategies using plasminogen activators in conjunction with specifically targeted antiplatelet and anticoagulant agents.
Is fiber mitochondrial volume density a good indicator of muscle fatigability to isometric exercise? The relationship between the ratio of interfibrillar mitochondrial volume density (Vvmit) to myofibrillar volume density (Vvmyo) and isometric fatigue characteristics of the human triceps surae was determined in six bodybuilders, six endurance athletes, and six active controls before and after 16 wk of isometric training at 30 or 100% maximal voluntary contraction (MVC) in six sedentary subjects in a unilateral exercise model. Time to fatigue at 30% MVC was significantly less in sedentary subjects before training than in the other subject groups, but it was similar to the other groups posttraining. Stereological analyses of type I fibers indicated that Vvmit/Vvmyo was less in bodybuilders than in other subjects. Training at 30% MVC increased type I fiber Vvmit/Vvmyo of the soleus by 11% but did not affect the gastrocnemii. Training at 100% MVC did not alter Vvmit/Vvmyo in any muscle, nor was this ratio changed in type II fibers by either training program. Despite the morphological differences, both training protocols increased relative endurance, although greater fatigue resistance was seen after training at 30% MVC. Correlation analyses indicated that isometric endurance and improvements in muscle endurance by isometric exercise were not dependent on increasing interfibrillar Vvmit or Vvmit/Vvmyo in either fiber type.
Electromechanical dissociation in newborns treated with extracorporeal membrane oxygenation: an extreme form of cardiac stun syndrome. OBJECTIVE: To recognize cardiac stun syndrome and electromechanical dissociation in patients receiving extracorporeal membrane oxygenation (ECMO), and to define patients at risk. DESIGN: Retrospective review. SETTING: Tertiary neonatal ICU. PATIENTS: Four newborn patients with cardiorespiratory failure who developed signs of cardiac stun syndrome and electromechanical dissociation early in the ECMO course. MEASUREMENTS AND MAIN RESULTS: Initially, these patients had metabolic acidosis, chest roentgenograms showing pulmonary granularity and moderate cardiomegaly, and symptoms of severe respiratory distress. Cardiac dysfunction was apparent after ECMO was begun, with poor perfusion, pale color, narrow pulse pressure, and tachycardia despite normovolemia. Within 1 to 2 hrs, electromechanical dissociation occurred manifested by the absence of pulse pressure, palpable pulse, cardiac sounds, and apical impulse while on 50% to 70% bypass. All patients survived. INTERVENTIONS: Patients received ECMO, calcium gluconate, sodium bicarbonate, and dobutamine. CONCLUSIONS: Patients with cardiac stun syndrome have symptoms similar to severe respiratory distress syndrome, and may require ECMO support. In the ECMO patient, cardiac stun syndrome and electromechanical dissociation can be confused with low circuit volume, pneumothorax, or cardiac tamponade. Early recognition of electromechanical dissociation may improve care and outcome. Cardiac stun syndrome can be treated successfully with ECMO.
Complete infarction of the eye complicating a choroidal malignant melanoma. Infarction of malignant melanoma of the choroid has been previously reported, but infarction of the whole eye in association with infarction of melanoma is a rare event that has not been previously described. We present such a case and discuss the possible pathogenesis.
Clinical characteristics and surgical management of vascular complications in patients undergoing cardiac catheterization: interventional versus diagnostic procedures. The purpose of this report is to define the clinical characteristics and outcome of surgical management of vascular complications after interventional cardiac catheterization and to contrast them to those after diagnostic cardiac catheterization. From October 1985 to December 1989, 101 patients were treated for 106 vascular complications after 1866 interventional and 5046 diagnostic cardiac catheterizations at the University of Michigan Medical Center. Interventional catheterizations resulted in 69 vascular complications in 64 patients (frequency 3.4%). The most common interventions included coronary angioplasty (34), of which 10 required percutaneous partial cardiopulmonary bypass, intraaortic balloon pump placement (14), and aortic valvuloplasty (11). Interventional catheter-related complications included hemorrhage (33), arterial thrombosis (18), pseudoaneurysm formation (12), catheter embolization (2), thromboembolism (2), as well as arteriovenous fistula, pseudoaneurysm, and arterial dissection (1 each). Fifteen of these 69 patients (24%) had suffered acute myocardial infarction just before their catheterization. Surgical repair was performed under local anesthesia in 70% of patients. Major vascular reconstructions were required in 9% of patients. Three percent of the involved lower extremities had to be amputated because of complications occurring after arterial puncture. Eight percent of the patients incurring vascular complications after interventional procedures died after operation. Diagnostic catheterizations resulted in 37 vascular complications in 37 patients (frequency 0.7%). In contrast to diagnostic cardiac catheterization, vascular complications after interventional cardiac catheterization occurred more frequently, were most often due to hemorrhage at the vascular access site, and occurred in high-risk, critically ill patients.
Staving off acute otitis media. When is prophylaxis with antibiotics desirable? Acute otitis media affects most young children and is the condition for which children are most frequently treated with antibiotics. A pattern of recurrent acute ear infections develops in some children and is a source of frustration for parents and physicians. Recurrent episodes can exacerbate asthma or other underlying medical problems, and long-term effects can include chronic otitis media with permanent middle-ear injury and, possibly, delay in psychomotor and language development. Antibiotic prophylaxis can reduce the number of episodes of acute otitis media in children at high risk for recurrent infection. There is no perfect antibiotic to prevent acute otitis media. However, the risks associated with the drugs described in this article are low. Prophylaxis with antibiotics does not prevent all episodes of acute otitis media but can reduce the number of episodes by 50%.
The mechanism responsible for diminished neutrophil production in neonates delivered of women with pregnancy-induced hypertension. The neonatal neutropenia after pregnancy-induced hypertension is a function of diminished neutrophil production. These studies test the hypothesis that this diminution is due to decreased production of neutrophilic growth factors, reduced responsiveness of neutrophil progenitors to these factors, or the presence of an inhibitor. While the concentrations of placentally derived colony-stimulating factors were similar in normotensive and hypertensive gestations, bioassay demonstrated less colony-stimulating activity in placental conditioned media from hypertensive gestations. Evaluation of the responsiveness of progenitors to recombinant factors revealed no differences between those from normotensive and hypertensive gestations. However, neutrophilic colony formation in vitro was significantly inhibited after the addition of conditioned media or sera from hypertensive gestations, whereas the addition of these from normotensive gestations had no inhibitory effect. Thus this common maternal-fetal disorder is associated with an inhibitor of neutrophil production, which is elaborated by the placenta and present in cord blood serum.
Transient white matter changes on MR images in children undergoing chemotherapy for acute lymphocytic leukemia: correlation with neuropsychologic deficiencies. The cranial magnetic resonance (MR) images of 25 children with acute lymphocytic leukemia (ALL) who were undergoing chemotherapy were retrospectively studied to determine the frequency of white matter changes and to analyze the significance of these observed changes in predicting subsequent neuropsychologic deficiencies. MR images showed transient white matter abnormalities in 17 of the 25 patients during consolidation therapy. Twelve of 20 children showed neuropsychologic deficits. There was no correlation between white matter changes and neuropsychologic deficits. In the subgroup of children under age 5 years at the time of diagnosis, 10 of 11 showed neuropsychologic deficits, and eight of 11 had white matter changes. Children under age 5 who undergo chemotherapy for ALL are at high risk to develop neuropsychologic deficiencies. Age at diagnosis is a reliable predictor of subsequent neuropsychologic deficits.
The risk of axillofemoral bypass grafting for acute vascular occlusion. The hypothesis of the present study is that axillofemoral bypass grafting for acute vascular occlusion has results significantly inferior to an elective procedure. We reviewed 53 patients undergoing primary axillofemoral bypass grafting at the University of Virginia from 1984 to 1989. We found that patients who were admitted with acute vascular occlusion had a higher incidence of perioperative complications (63% vs 26%, p = 0.001), perioperative mortality (26% vs 3%, p less than 0.05), lower graft patency at 1 year (60% vs 90%, p less than 0.05), lower rate of freedom from reoperation in first year (50% vs 82%, p less than 0.01), and lower rates of limb salvage (76% vs 94%, p less than 0.05) than patients undergoing axillofemoral bypass grafting for chronic symptoms or conditions. These two groups did not differ in any of the other risk factors or perioperative characteristics examined. We conclude axillofemoral bypass grafting performed for indications other than acute vascular occlusion is associated with acceptable morbidity, mortality, graft patency, and limb salvage rates.
Na+, K(+)-ATPase inhibition and intracellular electrolyte content in essential and secondary hypertension. A crucial role of humoral factors in the pathogenesis of primary hypertension is discussed. In 1982 Hamlyn et al demonstrated the presence of a Na+, K(+)-ATPase inhibitor in the plasma of essential hypertensives and showed a significant correlation of the Na+, K(+)-ATPase inhibition with the blood pressure. In this study we examined whether an Na+, K(+)-ATPase inhibitor could be found in the blood of essential hypertensives as compared to patients with secondary hypertension (renal hypertension, renal artery stenosis, pheochromocytoma). Second, the possible correlation between an inhibition of Na+, K(+)-ATPase and the intracellular electrolyte composition was examined. The results demonstrate a similar reduction of Na+, K(+)-ATPase inhibition in both essential hypertensives and secondary hypertensives as compared to normotensive controls. Further, the intracellular electrolyte composition (Na+, Na; K+, Ca) does not show a significant correlation to the degree of Na+, K(+)-ATPase inhibition, whereas a significant correlation between the degree of Na+, K(+)-ATPase inhibition and intracellular Cl- concentration could be demonstrated. The present study shows that an endogenous Na+, K(+)-ATPase inhibitor is also present in secondary forms of hypertension, thus implying that a specific role in the pathogenesis of primary hypertension for an Na+, K(+)-inhibitor is unlikely.