bluuebunny/crossref_metadata_2025_split huggingface dataset:
The role of luminance and chromatic cues in emmetropisation
Authors: Rucker Frances J 
Published: May 2013

AbstractPurposeAt birth most, but not all eyes, are hyperopic. Over the course of the first few years of life the refraction gradually becomes close to zero through a process called emmetropisation. This process is not thought to require accommodation, though a lag of accommodation has been implicated in myopia development, suggesting that the accuracy of accommodation is an important factor. This review will cover research on accommodation and emmetropisation that relates to the ability of the eye to use colour and luminance cues to guide the responses.Recent FindingsThere are three ways in which changes in luminance and colour contrast could provide cues: (1) The eye could maximize luminance contrast. Monochromatic light experiments have shown that the human eye can accommodate and animal eyes can emmetropise using changes in luminance contrast alone. However, by reducing the effectiveness of luminance cues in monochromatic and white light by introducing astigmatism, or by reducing light intensity, investigators have revealed that the eye also uses colour cues in emmetropisation. (2) The eye could compare relative cone contrast to derive the sign of defocus information from colour cues. Experiments involving simulations of the retinal image with defocus have shown that relative cone contrast can provide colour cues for defocus in accommodation and emmetropisation. In the myopic simulation the contrast of the red component of a sinusoidal grating was higher than that of the green and blue component and this caused relaxation of accommodation and reduced eye growth. In the hyperopic simulation the contrast of the blue component was higher than that of the green and red components and this caused increased accommodation and increased eye growth. (3) The eye could compare the change in luminance and colour contrast as the eye changes focus. An experiment has shown that changes in colour or luminance contrast can provide cues for defocus in emmetropisation. When the eye is exposed to colour flicker the eye grows almost twice as much, and becomes more myopic, compared to when the eye is exposed to luminance flicker.SummaryNeural responses of the luminance and colour mechanisms direct accommodation and emmetropisation mechanisms to different focal planes. Therefore, it is likely that the set point of refraction and accommodation is dependent on the sensitivity of the eye to changes in spatial and temporal, colour and luminance contrast.
Effects of muscarinic agents on chick choroids in intact eyes and eyecups: evidence for a muscarinic mechanism in choroidal thinning
Authors: Nickla Debora L , Zhu Xiaoying , Wallman Josh 
Published: May 2013

AbstractPurposeIn chicks, ocular growth inhibition is associated with choroidal thickening and growth stimulation with choroidal thinning, suggesting a mechanistic link between the two responses. Because muscarinic antagonists inhibit the development of myopia in animal models by a non‐accommodative mechanism, we tested the hypothesis that agonists would stimulate eye growth and thin the choroid. We also hypothesized that the effective growth‐inhibiting antagonists would thicken the choroid.MethodsChicks, age 12–16 days, were used. In vivo: Agonists: Single intravitreal injections (20 μL) of oxotremorine (oxo), pilocarpine (pilo), carbachol (carb), or arecaidine (arec) were given to otherwise untreated eyes. A‐scan ultrasonography was done prior to injections, and at 3, 24, 48 and 72 h. Antagonists: −10D lenses were worn on one eye for 4 days. Atropine (atro), pirenzepine (pirz), oxyphenonium (oxy) or dicyclomine (dicy) were injected (20 μL) daily into lens‐wearing eyes; saline injections were done as controls. Ultrasonography was done on d1 and on d4; on d4 measurements were done before and 3 h after injections. In vitro: Paired eyecups of retinal pigment epithelium (RPE), choroid and sclera were made from 1‐week old chicks. All drugs except atropine were tested on one eyecup, its pair in plain medium. Choroidal thickness was measured at various times over 48 h.ResultsAgonists: In vivo, oxotremorine caused an increase in the rate of axial elongation (drug vs saline: 24–72 h: 338 μm vs 250 μm; p < 0.001). All except pilocarpine caused choroidal thinning by 24 h (oxo, carb and arec vs saline: −25, −35 and −46 μm vs 3 μm). In vitro, all agonists thinned choroids by 24 h (oxo: −6 vs 111 μm; pilo: 45 vs 212 μm; carb: −58 vs 65 μm; arec: 47 vs 139 μm; p < 0.05). Antagonists: Atropine, pirenzepine and oxyphenonium inhibited the development of myopia in negative lens‐wearing eyes, and also caused choroidal thickening (drug vs saline: 42, 80, 88 vs 10 μm per 3 h). In vitro, pirenzepine thickened choroids by 3 h (77 vs 2 μm, p < 0.01).ConclusionsMuscarinic agonists caused choroidal thinning in intact eyes and eyecups, supporting a role for acetylcholine in the choroidal response to hyperopic defocus or form deprivation. Only oxotremorine stimulated eye growth, which is inconsistent with a muscarinic receptor mechanism for antagonist‐induced eye growth inhibition. The dissociation between choroidal thinning and ocular growth stimulation for the other agonists in vivo suggest separate pathways for the two.
Dynamics of active emmetropisation in young chicks – influence of sign and magnitude of imposed defocus
Authors: Hammond David S , Wallman Josh , Wildsoet Christine F 
Published: May 2013

AbstractPurposeYoung eyes compensate for the defocus imposed by spectacle lenses by changing their rate of elongation and their choroidal thickness, bringing their refractive status back to the pre‐lens condition. We asked whether the initial rate of change either in the ocular components or in refraction is a function of the power of the lenses worn, a result that would be consistent with the existence of a proportional controller mechanism.MethodsTwo separate studies were conducted; both tracked changes in refractive errors and ocular dimensions. Study A: To study the effects of lens power and sign, young chicks were tracked for 4 days after they were fitted with positive (+5, +10 or +15 D) or negative (−5, −10, −15 D) lenses over one eye. In another experiment, biometric changes to plano, +1, +2 and +3 D lenses were tracked over a 24 h treatment period. Study B: Normal emmetropisation was tracked from hatching to 6 days of age and then a defocusing lens, either +6 D or −7 D, was fitted over one eye and additional biometric data collected after 48 h.ResultsIn study A, animals treated with positive lenses (+5, +10 or +15 D) showed statistical similar initial choroid responses, with a mean thickening 24 μm h−1 over the first 5 h. Likewise, with the low power positive lenses, a statistically similar magnitude of choroidal thickening was observed across groups (+1 D: 46.0 ± 7.8 μm h−1; +2 D: 53.5 ± 9.9 μm h−1; +3 D 53.3 ± 24.1 μm h−1) in the first hour of lens wear compared to that of a plano control group. These similar rates of change in choroidal thickness indicate that the signalling response is binary in nature and not influenced by the magnitude of the myopic defocus. Treatments with −5, −10 and −15 D lenses induced statistically similar amounts of choroidal thinning, averaging −70 ± 15 μm after 5 h and −96 ± 45 μm after 24 h. Similar rates in inner axial length changes were also seen with these lens treatments until compensation was reached, once again indicating that the signalling response is not influenced by the magnitude of hyperopic defocus. In study B, after 48 h of +6 D lens treatment, the average refractive error and choroidal changes were found to be larger in magnitude than expected if perfect compensation had taken place, with a + 2.4 D overshoot in refractive compensation.ConclusionTaken together, our results with both weak and higher power positive lenses suggest that eye growth is guided more by the sign than by the magnitude of the defocus, and our results for higher power negative lenses support a similar conclusion. These behaviour patterns and the overshoot seen in Study B are more consistent with the behaviour of a bang‐bang controller than a proportional controller.
Minor oral surgery in a patient with a combined fracture and congenital malformation of the first cervical vertebra
Authors: O'Neill F. , Thayer T. , Balmer M.C. , Begley A. 
Published: May 2013

AbstractHere we present a case study of a patient who presented with both a congenital failure of fusion of the posterior arch of the atlas and a concomitant Jefferson fracture of the anterior arch following trauma. This patient required minor oral surgery prior to open reduction and internal fixation of the fracture, and the considerations are discussed.
Predictors of Pacemaker Dependence and Pacemaker Dependence as a Predictor of Mortality in Patients with Implantable Cardioverter Defibrillator
Authors: SOOD NITESH , CRESPO ERIC , FRIEDMAN MEIR , GUERTIN DANETTE , ZWEIBEL STEVEN , KLUGER JEFFREY , CLYNE CHRISTOPHER A. 
Published: May 2013

BackgroundThe prevalence, predictors, and survival for the development of pacemaker dependence (PD) in patients implanted with an implantable cardioverter defibrillator (ICD) are unknown.MethodsThis was a retrospective analysis of 1,550 consecutive patients with ICD implantation at a single center from 1996 to 2008 with a mean of 4.2 ± 3.4 years. Patients with implant intrinsic heart rates less than 40 beats/min (n = 48) and cardiac resynchronization therapy (n = 444) were excluded leaving 1,058 patients in this study. PD was defined as an intrinsic rhythm <40 beats/min after inhibiting the pacemaker, <50 beats/min with transient symptoms of dizziness relieved by resumption of pacing and right ventricle pacing despite algorithms to promote intrinsic conduction at the 3 monthly follow‐up ICD clinic visits. Multivariate regression and Cox proportional hazard models were used for analysis.ResultsThe mean age was 64 ± 13 years; 79% were male with a primary indication for the ICD in 57%. PD occurred in 142 (13.4%) of patients, with a mean time to PD of 2.6 ± 1.9 years. PD was associated with a 48% increased odds for mortality versus non‐PD ICD patients during the mean follow‐up time of 4.2 ± 3.4 years (adjusted odds ratio = 1.48 [95% confidence interval 1.080–2.042]; P = 0.015). Older age, a history of atrial fibrillation, amiodarone use, and secondary prevention were the strongest predictors for the development of PD.ConclusionsIn this single‐center ICD cohort, the development of PD was not uncommon and was associated with decreased survival.
Autonomic cardio‐respiratory reflex reactions and superselective ophthalmic arterial chemotherapy for retinoblastoma
Authors: Phillips Trudie J. , McGuirk Simon P. , Chahal Hardeep K. , Kingston Judith , Robertson Fergus , Brew Stefan , Roebuck Derek , Hungerford John L. , Herod Jane 
Published: May 2013

SummaryObjectiveTo describe our experience with superselective ophthalmic artery chemotherapy (SOAC) in retinoblastoma and to report the serious adverse cardio‐respiratory reactions we have observed.MethodsSOAC was performed using a standardized protocol for general anesthesia, ophthalmic artery catheterization, and pulsed infusion of melphalan. Adverse reactions were defined as those in which the patient required active treatment to maintain cardio‐respiratory stability.ResultsBetween December 2008 and May 2012, 54 eyes in 52 patients were treated. 143 catheterization procedures were performed, with a technical success rate of 93% (n = 133). There were no deaths or major complications. Adverse cardio‐respiratory reactions developed during 35 procedures (24%; 95% CI, 18–32%). All reactions occurred during second or subsequent catheterization procedures (39%; 95% CI, .29–49%) and were characterized by hypoxia, reduced lung compliance, systemic hypotension and bradycardia. Adverse events were successfully treated in all patients. One procedure was abandoned due to prolonged hemodynamic instability.ConclusionAdverse cardio‐respiratory reactions are commonly observed in SOAC for retinoblastoma. We believe that the adverse clinical signs represent an autonomic reflex response, akin to the trigemino‐cardiac or oculo‐respiratory reflexes, and all patients should be considered at‐risk. Reactions occur only during second or subsequent procedures and can be life‐threatening. The routine use of intravenous atropine does not seem to have altered the incidence or severity of these reactions. Anesthetists and interventional neuroradiologists involved in SOAC must be vigilant to ensure adverse reactions, when they develop, are treated quickly and effectively.
Postoperative pain, nausea and vomiting following adeno‐tonsillectomy – a long‐term follow‐up
Authors: Stanko Dana , Bergesio Ric , Davies Kylie , Hegarty Mary , von Ungern‐Sternberg Britta S. 
Published: May 2013

SummaryBackgroundAdenotonsillectomy is a common pediatric surgical procedure. Our knowledge of the recovery profile, parental understanding, and expectations is limited. We aimed to assess the incidence of pain, nausea, and vomiting in children undergoing adenotonsillectomy on postoperative day 3 and 7. We also wished to evaluate parental understanding regarding discharge instructions as well as parental expectations and experience of their child's recovery.MethodsWe enrolled 100 children (0–16 years) undergoing elective adenotonsillectomy. On day 3 and 7, parents were questioned about their child's level of pain, nausea/vomiting and their understanding regarding postoperative instructions.ResultsHundred children (median, 6.68 years) were recruited. 52% of parents rated their child's pain as VAS ≥ 5 on day 3, dropping to 30% by day 7. Almost 33% of patients experienced nausea on day 3, dropping to 11.6% by day 7. A similar trend was observed for postoperative vomiting. Most parents, 89%, agreed that postoperative instructions were clear. However, knowledge regarding when to seek emergency medical advice was found to be lacking. On day 7, only 44% of parents reported that their child's recovery met their expectations.ConclusionAdenotonsillectomy is associated with significant pain and PONV, persisting into the seventh postoperative day. Parental education and information seems inadequate and needs to be improved.
Use of the Bonfils intubating fibrescope in a baby with a severely compromised airway
Authors: Krishnan Priya L. , Thiessen Bernd H. 
Published: May 2013

SummaryWe report the successful use of a 2‐mm rigid Bonfils intubation endoscope as a rescue device in a 5‐week‐old baby presenting with an unstable airway due to massive macroglossia and multiple hemorrhagic lymphangiomata compressing the airway and resulting in a Cormack and Lehane grade 4 view. The limited intraoral space rendered it impossible to visualize the laryngeal inlet or insert a laryngeal mask, Glidescope or Airtraq blade into the patient's mouth. A 2‐mm Bonfils fibrescope passed easily into the patient's mouth and facilitated a grade 1 view of the laryngeal inlet with subsequent successful intubation at first attempt with a 3.5‐mm uncuffed endotracheal tube. There are very few alternatives to rescue such an airway in this age group with this type of pathology and surgical intervention would have been difficult due to the vascular nature of the lesion. Bonfils intubation endoscopes (Karl Storz Endoscopy, Tuttlingen, Germany) are a series of reusable devices consisting of a rigid metal tube with a fixed 40° anterior tip curvature containing a fibreoptic bundle. They are available in three sizes with outside diameters of 2, 3.5, or 5 mm. The advantage of the pediatric 2‐mm Bonfils fibrescope is that it allows intubation with a 2.5‐mm endotracheal tube. There is a paucity of the literature pertaining to the use of the Bonfils endoscope as a rescue device for intubation of small infants and neonates. In our case, the infant's airway was compromised as a result of a receding mandible, large protruding tongue, glottic distortion, and limited intraoral space. This prevented the use of bulkier rescue airway devices with the potential for traumatic manipulation, which could have lead to rapid deterioration of an already unstable airway. We feel that many clinicians are unaware of the benefits of the Bonfils fibrescope and suggest further studies to increase its use in elective and emergency situations.
Robust closed‐loop control of induction and maintenance of propofol anesthesia in children
Authors: West Nicholas , Dumont Guy A. , van Heusden Klaske , Petersen Christian L. , Khosravi Sara , Soltesz Kristian , Umedaly Aryannah , Reimer Eleanor , Ansermino J. Mark 
Published: May 2013

SummaryBackgroundDuring closed‐loop control, a drug infusion is continually adjusted according to a measure of clinical effect (e.g., an electroencephalographic depth of hypnosis (DoH) index). Inconsistency in population‐derived pediatric pharmacokinetic/pharmacodynamic models and the large interpatient variability observed in children suggest a role for closed‐loop control in optimizing the administration of intravenous anesthesia.ObjectiveTo clinically evaluate a robustly tuned system for closed‐loop control of the induction and maintenance of propofol anesthesia in children undergoing gastrointestinal endoscopy.MethodsOne hundred and eight children, aged 6–17, ASA I‐II, were enrolled. Prior to induction of anesthesia, NeuroSENSE™ sensors were applied to obtain the WAVCNS DoH index. An intravenous cannula was inserted and lidocaine (0.5 mg·kg−1) administered. Remifentanil was administered as a bolus (0.5 μg·kg−1), followed by continuous infusion (0.03 μg·kg−1·min−1). The propofol infusion was closed‐loop controlled throughout induction and maintenance of anesthesia, using WAVCNS as feedback.ResultsAnesthesia was closed‐loop controlled in 102 cases. The system achieved and maintained an adequate DoH without manual adjustment in 87/102 (85%) cases. Induction of anesthesia (to WAVCNS ≤ 60) was completed in median 3.8 min (interquartile range (IQR) 3.1–5.0), culminating in a propofol effect‐site concentration (Ce) of median 3.5 μg·ml−1 (IQR 2.7–4.5). During maintenance of anesthesia, WAVCNS was measured within 10 units of the target for median 89% (IQR 79–96) of the time. Spontaneous breathing required no manual intervention in 91/102 (89%) cases.ConclusionsA robust closed‐loop system can provide effective propofol administration during induction and maintenance of anesthesia in children. Wide variation in the calculated Ce highlights the limitation of open‐loop regimes based on pharmacokinetic/pharmacodynamic models.
The perioperative course of factor XIII and associated chest tube drainage in newborn and infants undergoing cardiac surgery
Authors: Gertler Ralph , Martin Klaus , Hapfelmeier Alexander , Tassani‐Prell Peter , Braun Siegmund , Wiesner Gunther 
Published: May 2013

SummaryBackgroundPerioperative acquired factor XIII deficiency has been looked upon as a potential cause of postoperative bleeding in adult cardiac surgery.MethodsForty‐four infants were prospectively studied for the time course of factor XIII in plasma and the effect on chest tube drainage (CTD) and transfusion requirements in the first 24 h after surgery. A reconstituted blood prime (RBP) with fresh–frozen plasma (FFP) and packed red blood cells (PRBC) was used. Samples were taken at baseline, after cardiopulmonary bypass and upon arrival in the ICU. Differences in blood loss and transfusion requirements based on a cutoff value of 70% factor XIII activity at the time of ICU admission were also calculated.ResultsBaseline factor XIII activity was 79%, decreased to 71% after CPB (P = 0.102) and increased back up to 77% at ICU arrival (P = 0.708). There was no significant correlation between factor XIII, CTD, age, cyanosis, platelet count, and transfusion requirements at any time point. Only preoperative fibrinogen levels correlated significantly with factor XIII activity. Perioperative blood transfusions (PRBC P = 0.712, FFP P = 0.909, platelets P = 0.807) and chest tube losses (P = 0.424 at 6 h and P = 0.215 at 24 h) were not significantly different above or below a 70% factor XIII activity at ICU arrival.ConclusionFactor XIII activity in infants with congenital heart defects is within the lower range of normal adults, independent of patient's age and the presence of cyanosis. Reconstituted blood prime maintains factor XIII activity at sufficient levels during pediatric cardiac surgery. We could not detect a correlation between FXIII and CTD.
Capillary Malformation—Arteriovenous Malformation Syndrome: Review of the Literature, Proposed Diagnostic Criteria, and Recommendations for Management
Authors: Orme Charisse M. , Boyden Lynn M. , Choate Keith A. , Antaya Richard J. , King Brett A. 
Published: May 2013

AbstractCapillary malformation–arteriovenous malformation syndrome is an autosomal dominant disorder caused by mutations in the RASA1 gene and characterized by multiple small, round to oval capillary malformations with or without arteriovenous malformations. Ateriovenous malformations occur in up to one‐third of patients and may involve the brain and spine. Although making the diagnosis is straightforward in some patients, there are other patients for whom diagnostic criteria may be helpful in their evaluation. Here we review the literature regarding capillary malformation−arteriovenous malformation syndrome, propose diagnostic criteria, and discuss the care of patients with this condition.
Transporter Associated with Antigen Processing Deficiency Syndrome: Case Report of an Adolescent with Chronic Perforated Granulomatous Skin Lesions Due to TAP2 Mutation
Authors: Konstantinou Paschalis , Kanariou Maria , Giliani Silvia C. , Pantelidaki Aikaterini , Kokolakis Athanasios , Tosca Androniki 
Published: May 2013

AbstractA previously unreported case of transporter associated with antigen processing (TAP) deficiency syndrome (with no parental consanguinity) due to a homozygous TAP2 mutation is presented. Characteristic nonhealing, chronic, ulcerative granulomatous leg lesions combined with recurrent otitis media and sinopulmonary infections led to this boy being diagnosed at 15 years old. The role of the dermatologist was crucial in making the correct diagnosis and thereby positively influencing the quality of life and life expectancy of this boy.
The interactions and essential effects of intrinsic insulin‐like growth factor‐I on Leishmania (Leishmania) major growth within macrophages
Authors: Reis L. C. , Ramos‐Sanchez E. M. , Goto H. 
Published: May 2013

SummaryPreviously, we showed in Leishmania infections that extrinsic insulin‐like growth factor (IGF)‐I favored Leishmania proliferation and leishmaniasis development. In this study, the interaction of intrinsically expressed IGF‐I and Leishmania (Leishmania) major in macrophages was addressed, and a key finding was the observation, using confocal microscopy, of the co‐localization of IGF‐I and parasites within macrophages. Following stimulation with interferon‐γ (IFN‐γ), which is known to inhibit IGF‐I production in macrophages, we observed a reduction in the expression of both IGF‐I mRNA and protein. This reduced expression was accompanied by a reduction in the cellular parasite load that was completely recovered with the addition of extrinsic IGF‐I, which suggests an essential role for IGF‐I in Leishmania growth.