Anticoagulation for the Acute Management of Ischemic Stroke

Few prospective studies support the use of anticoagulation during the acute phase of ischemic stroke, though observational data suggest a role in certain populations. Depending on the mechanism of stroke, systemic anticoagulation may prevent recurrent cerebral infarction, but concomitantly carries a risk of hemorrhagic transformation. In this article, we describe a case where anticoagulation shows promise for ischemic stroke and review the evidence that has discredited its use in some circumstances while showing its potential in others.     

Ensembles of endothelial and mural cells promote angiogenesis in prenatal human brain

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Role of diastolic vortices in flow and energy dynamics during systolic ejection

MRI-based computational fluid dynamics simulations were performed in the left ventricles of two adult porcine subjects with varying physiological states (before and after an induced infarction). The hypothesis that diastolic vortices store kinetic energy and assist systolic ejection was tested, by performing systolic simulations in the presence and absence of diastolic vortices. The latter was achieved by reinitializing the entire velocity field to be zero at the beginning of systole. A rudimentary prescribed motion model of a mitral valve was included in the simulations to direct the incoming mitral jet towards the apex. Results showed that the presence or absence of diastolic vortex rings had insignificant impact on the energy expended by walls of the left ventricles for systolic ejection for both the porcine subjects, under all physiological conditions. Although substantial kinetic energy was stored in diastolic vortices by end diastole, it provided no appreciable savings during systolic ejection, and most likely continued to complete dissipation during systole. The role of diastolic vortices in apical washout was investigated by studying the cumulative mass fraction of passive dye that was ejected during systole in the presence and absence of vortices. Results indicated that the diastolic vortices play a crucial role in ensuring efficient washout of apical blood during systolic ejection.     

Structural principles for the propeller assembly of beta-sheets: the preference for seven-fold symmetry.

Twisted beta-sheets, packed face to face, may be arranged in circular formation like blades of a propeller or turbine. This beta-propeller fold has been found in three proteins: that in neuraminidase consists of six beta-sheets while those in methylamine dehydrogenase and galactose oxidase are composed of seven beta-sheets. A model for multisheet packing in the beta-propeller fold is proposed. This model gives both geometrical parameters of the beta-propellers composed of different numbers of sheets and patterns of residue packing at their sheet-to-sheet interfaces. All the known beta-propeller structures have been analyzed, and the observed geometries and residue packing are found to be in good agreement with those predicted by models. It is shown that unusual seven-fold symmetry is preferable to six- or eight-fold symmetry for propeller-like multi-sheet assembly. According to the model, a six-beta-sheet propeller has to have predominantly small residues in the beta-strands closed to its six-fold axis, but no strong sequence constraints are necessary for a seven-fold beta-propeller.     

脑室出血合并脑积水行脑室外引流高危因素的临床分析

目的:探讨脑室出血后未立即行脑室外引流术发生脑积水的指征和时机。方法:回顾性分析2009年1月到2015年9月我院收治的98例脑室内出血患者的临床资料。结果:98例患者中,28例(28.6%)患者需要行脑室外引流术。全脑室出血是最常见的类型(49例,50%),这些患者中24例(49%)需要行脑室外引流术。在脑室外引流术组和非脑室外引流术组平均m GS分别是17±5.1(12-28)和8±4.2(2-20)(P0.001)。与脑室外引流术相关的因素包括影像学表现为脑积水、中线移位5 mm、GCS评分8分、m GS13分、三脑室m GS=5及四脑室m GS=5分。多因素回归分析中,m GS13分、GCS评分8分和四脑室m GS=5分仍是重要的影响因素。大部分患者(24例,85.7%)在有脑积水症状时很快行脑室外引流术,有4例患者在48小时后行脑室外引流术。结论:昏迷、m GS13分和四脑室扩大使行脑室外引流术的风险增大。大部分患者在脑室出血后一天内行脑室外引流术,很少一部分患者在48小时后行脑室外引流术。     

Applications of KAM theory to population dynamics

Computer simulations have shown that several classes of population models, including the May host-parasitoid model and the Ginzburg–Taneyhill ‘maternal-quality’ single species population model, exhibit extremely complicated orbit structures. These structures include islands-around-islands, ad infinitum, with the smaller islands containing stable periodic points of higher period. We identify the mechanism that generates this complexity and we discuss some biological implications.     

Radiofrequency Catheter Ablation Of Atrioventricular Nodal Reentry Tachycardia In A Patient With Inferior Vena Cava Anomaly

Curative radiofrequency catheter modification of the slow pathway is the recommended therapy for patients suffering from recurrent symptomatic atrioventricular nodal reentry tachycardia. This is usually performed via femoral vein and the inferior vena cava (IVC). Presence of venous occlusion or complex venous anomaly involving the IVC may preclude this approach. Here, we report a case with a complex venous anomaly involving the inferior vena cava, who underwent electrophysiological study and successful radiofrequency ablation by an alternative approach.     

蛤蚧前背侧室嵴(ADVR)的分区及细胞形态学研究

采用解剖学方法和绀织学方法仔细观察,分析蛤蚧（Gekko gecko）前背侧室嵴（ADVR）的形态学分区,发现以ADVR表面的浅沟为标记,参照细胞着色深浅,细胞密度分布特征以及细胞形态大小,可将ADVR分为内侧区（ma）、嘴外侧区（rla）和尾外侧区（cla）等3个部分,为ADVR的结构功能的深入研究提供了形态学依据。