脂膜微泡结合凝血酶原复合物的制备

目的:制备结合凝血酶原复合物(PCC)的阴离子脂膜微泡,评价微泡的理化性质。材料和方法:采用机械振荡直接连接法,分两组(于机械振荡之前或之后加入),制备结合PCC的阴离子脂膜微泡,观察并检测洗涤前后微泡的理化性质。结果:微泡与PCC的结合率及Ⅸ因子活性:两组间比较无明显差异(P>0.05),但洗涤后结合率由洗涤前的95%降为80%,活性由90%降为19%。结论:直接连接法可制备结合PCC的阴离子脂膜微泡,微泡与PCC结合率较高,且洗涤前能保持Ⅸ因子较高的活性。     

机械通气患者的呼吸道护理

目的：探讨机械通气患者呼吸道的护理以及并发症的预防；方法：查阅有关机械通气护理的文献；结果：呼吸衰竭患者在使用机械通气治疗的过程中护理不当可引起呼吸机相关肺炎、气管阻塞、气管损伤、低氧血症等；结论：加强机械通气患者的呼吸道护理可避免呼吸道并发症的发生。     

聚苯醚热固性改性及其性能研究

通过溴化聚苯醚和格利雅试剂反应，将不饱和基团烯丙基引入聚苯醚中实现其热固性改性，由^1H-NMR和FTIR进行结构表征。确定了烯丙化聚苯醚的固化工艺，并对其固化产物性能进行测试。结果表明：按合成新工艺制备的热固性聚苯醚，其固化产物具有优异的介电性能(低介电常数、低介电损耗因子)，良好的耐溶剂性能和低吸湿性。     

葡萄糖酸内酯为凝固剂时大豆蛋白的胶凝特性

测定了以葡萄糖酸内酯(GDL)作为凝固剂时不同热处理条件下大豆蛋白主要组分———7S和11S单独胶凝时的流变学曲线,证实了蛋白质的充分变性是GDL引发大豆蛋白胶凝的前提,且已充分热变性的7S和11S组分在单独胶凝时具有大致相当的凝胶强度.通过测定7S和11S组分的物理化学性质,解释了在以GDL作为凝固剂时两组分表现出基本相似的胶凝能力,与7S组分较高的疏水性和11S组分较高的巯基含量有关.     

Dual microcatheter and guidewire snare technique for retrieval of intravascular foreign body: technical note

A transjugular snare technique was used to retrieve a stretched, residual mechanical detachable coil which extended from the cavernous sinus to the femoral vein, obliterating the transpetrosal route for further embolisation. The coil was snared by a microguidewire. Our new technique is described in this paper. Received: 19 April 1995 Accepted: 31 July 1995     

人工心瓣膜患者微栓子信号和凝血活性的相关性研究

目的 :研究人工心瓣膜患者脑动脉微栓子信号 (MES)的数量及相对强度与凝血活性的相关性。方法 :采用双门深经颅多普勒 (TCD)检测人工心瓣膜患者脑动脉MES ,同时检测患者凝血酶原时间国际通用比值 (INR) ,观察MES数量及相对强度与INR的相关性。结果 :MES阳性发现率 83 33% (2 5 30 ) ,MES出现频率 0～ 4 0 4 (中位数 4 0 )个 h ,MES平均相对强度 11～ 38(2 3 6 3±5 13)dB。INR1 12～ 3 5 1(1 95± 0 6 9)。MES数量及相对强度与INR无相关性。结论 :人工心瓣膜患者脑动脉MES与凝血活性无关 ,提示微栓子物质不是血栓性的     

甲壳素溶液流变性能的初步研究

用热重分析仪和高级流变扩展系统分别研究了提纯工艺对甲壳素的影响和甲壳素／二氮乙酸溶液的流变特性。结果表明，提纯后的甲壳素为纯白色，且杂质含量减少。甲壳素／二氯乙酸溶液的表观粘度随剪切速率的增加而减小，结构粘度指数随浓度的增加而减小。剪切应力一剪切速率的曲线随着溶液浓度的增加而上移，浓度越大，其非牛顿指数n越小。该结构为确定合理的甲壳素纤维原丝生产工艺提供了科学依据。     

A Biomechanical Double Sac (Pericardium-Pebax) for Specially Shaped Artificial Ventricles: A Computerized Study to Evaluate Its Mechanical and Volumetric Properties

Abstract: For original ovoid shaped artificial ventricles. a biomechanical double sac consisting of a biological sac (porcine pericardium) as the blood contact interface and a synthetic sac (Pebax 3533) as the mechanical support to assume systolic-diastolic dynamic constraints was conceived. The volumetric and mechanical properties were assessed with a three-dimensional modeling of Pebax sacs and computerized simulations of their systolic distortions for both right and left ventricular configurations. The stresses and strains of these sacs were represented as quantitative mappings for a maximum end-systolic state and were below the respective threshold values above which the Pebax material is jeopardized for permanent structure impairment. After fatigue tests applied on Pebax strips under the alleged working conditions of Pebax sacs, the material structure was unchanged and maintained its intrinsic mechanical properties. The theoretical maximum stroke volumes were 74.4 cm³ and 62.4 cm for the left and right ventricular configurations, respectively. With these mechanical and volumetric features, the biomechanical double sac concept was considered valid and could be provided for a consequent specific total artificial heart.     

The effect of the synthetic neuroprotective dipeptide noopept on glutamate release from rat brain cortex slices

The level of spontaneous and K⁺-stimulated release of endogenous glutamate was studied in experiments on slices of brain cortex of Wistar rats. Pronounced spontaneous release of the neuromediator and its increase under conditions of stimulation were registered by high-performance liquid chromatography with electrochemical detection. The effect of the nootropic and neuroprotective dipeptide Noopept (GVS-111) on release of glutamate was investigated. The peptide in concentrations of 10^?5 and 10^?6 M caused a statistically significant decrease in spontaneous and K⁺-stimulated glutamate release. This effect could be the basis of the neuroprotective action of the peptide, suggesting that further studies of Noopept as neuroprotector are very promising.     

Turbulent stress measurements downstream of three bileaflet heart valve designs in pigs

Objective: Mechanical heart valves can cause thromboembolic complications, possibly due to abnormal flow patterns that produce turbulence downstream of the valve. The objective of this study was to investigate whether three different bileaflet valve designs would exhibit clinically relevant differences in downstream turbulent stresses. Methods: Three bileaflet mechanical heart valves (Medtronic Advantage^®, CarboMedics© Orbis™ Universal and St. Jude Medical^® Standard) were implanted into 19 female 90 kg pigs. Blood velocity was measured during open chest conditions in the cross sectional area downstream of the valves with 10 MHz ultrasonic probes connected to a modified Alfred^® Pulsed Doppler equipment. As a measure of turbulence, Reynolds normal stress (RNS) was calculated at three different cardiac output ranges (3–4, 4.5–5.5, 6–7 L/min). Results: Data from 12 animals were obtained. RNS correlated with increasing cardiac outputs. The highest instantaneous RNS observed in these experiments was 47 N/m², and the mean RNS taken spatially over the cross sectional area of the aorta during systole was between 3 N/m² and 15 N/m². In none of the cardiac output ranges RNS values exceeded the lower critical limit for erythrocyte or thrombocyte damage for any of the valve designs. Conclusions: Reynolds normal stress values were below 100 N/m² for all three valve designs and the difference in design was not reflected in generation of turbulence. Hence, it is unlikely that any of the valve designs causes flow induced damage to platelets or erythrocytes.