冠心病患者无症状性心肌缺血的动态心电图探讨

目的 探讨冠心病（CHD）患者无症状性心肌缺血（SMI）的动态心电图（DCG）的临床特点. 方法 对216例CHD患者应用12导联DCG进行24 h监测. 结果 192例有1930阵次心肌缺血发作,其中SMI占1650阵次（85.4%）.SMI压低次数及持续时间与有症状性心肌缺血差异有显著性（P＜0.01）.白天（6：00～18：00）发作频率是夜间（18：00～24：00）的2.40倍,发作高峰为6：00～12：00,0：00～6：00最少,SMI ST压低过程中伴有明显的心率上升,发作前和发作时心率比较有显著差异（P＜0.01）. 结论 SMI检出率远高于有症状心肌缺血,24小时动态心电图对无症状性心肌缺血的预测具有重要价值.     

Fe3O4核桃形球状颗粒和八面体微晶结构的可控合成与磁学性质

通过K4[Fe（CN）6]与K3[Fe（CN）6]在NaOH溶液中180℃水热反应12h得到Fe3O4核桃形球状颗粒和八面体微晶结构,并通过控制乙二醇的加入量可控合成了单一形貌的Fe3O4八面体微晶结构。采用X射线衍射仪、扫描电镜和透射电子显微镜对产物进行表征,并在室温下测试了它们的磁学性能,结果表明,Fe3O4核桃形球状颗粒和八面体微晶结构为单晶立方相结构,其尺寸分别约为2．2～8．6μm和1．6～12．5μm,矫顽力（Hc）分别为150．57Oe和75．28Oe,饱和磁化强度（Ms）分别为97．634emu／g和101．90emu／g,剩余磁化强度（Mr）分别为12．05emu／g和6．69emu／g。通过改变溶液中碱的浓度可实现不同尺寸核桃形球状颗粒的可控合成．研究了乙二醇在Fe3O4八面体的形成过程中起着关键作用,并提出了其可能的生长机理。     

基于FRCM和FLAR的水文过程遍历特征分析模型及其应用

提出利用模糊粗糙聚类（FRCM）、自相关趋势图和模糊最小一乘回归（FLAR）对水文过程的遍历性特征进行研究，以上海54年（1951～2004）的降水为例，进行了具体的计算和分析，并利用离差系数作了印证性分析．结果表明：上海4～6和9月具有过程遍历性特征，所以，从长时间尺度来看，上海4～6和9月的降水量总体上不会呈长期下降趋势，在某个时期都会向该月份的降水均值回归．     

瑞替普酶治疗急性心肌梗死（AMI）的临床观察

目的对比观察瑞替普酶（reteplase rPA）与尿激酶用于急性心肌梗死（AMI）溶栓治疗的效果。方法从2006年10月到2008年10月,共收治38例AMI患者,随机接受r—PA或尿激酶溶栓治疗,观察溶栓再通率及不良反应发生率。结果溶栓后2h再通率rPA组为89．47％,尿激酶组68．42％（P〈0．01）。结论瑞替普酶治疗AMI再通率高,疗效确切,值得临床推广。     

2．4-6．0GHz超宽带低噪声放大器的设计

采用标准0．5μmGaAsPHEMT工艺设计了工作频段在2．4—6GHz可应用于无线局域网（WLAN）和超宽带（UWB）接收机的超宽带低噪声放大器。从宽带电路的选择、高频电路设计的器件选择和电路结构的选择等方面讨论了如何进行超宽带低噪声放大器的设计。结果表明,通过合适的电路结构和器件参数选择,可以采用0．5μmGaAsPHEMT工艺制备满足超宽带系统要求的低噪声放大器。在UWB3．1～5．15GHz低频带内,该LNA增益20．8～21．6dB,噪声系数低于0．9～1．1dB,输入输出驻波比均小于一10dB。在2．4～3GHz频带（涵盖802．11b／g的使用范围）内,该LNA增益20．8～21．5dB,噪声系数低于2dB,输入输出驻波比均小于-10dB。在频带5．2—6GHz,该LNA的噪声系数增大到1．332dB。增益则从21．4dB下降到19．7dB。电路的工作电压为3．3V。     

检测血浆纤维蛋白原含量对临床诊疗冠心病的指导意义

目的探讨血浆纤维蛋白原含量变化与冠状动脉病变严重程度的关系。方法选择AMI患者20例（AMI组）,48小时内劳力型心绞痛加剧和出现自发性心绞痛患者24例（UAP）,典型心绞痛发作,其性质在1～3个月内无法改变的SAP患者18例（SAP组）．健康对照20例,采用美国库尔特公司的ACL-9000全自动血凝分析仪,测定其血浆,进行比较分析。结果AMI组和UAP组患者的血浆纤维蛋白原含量均高于SAP组和健康对照组（P〈0.05）。但AMI组与UAP组患者之间血浆纤维蛋白原含量无显著性差异（P〉0．05）。结论血浆纤维蛋白原含量与冠状动脉病变严重程度相关,急性冠状动脉综合征时体内处于高凝状态,抗凝和溶栓治疗有助于降低冠状动脉实践的危险性。     

盐酸戊乙奎醚对大鼠感染性脑水肿AQP4表达的影响

目的：研究盐酸戊乙奎醚对感染性脑水肿保护作用的机制。方法：采用左颈内动脉注射脂多糖复制大鼠感染性脑水肿模型,将84只雄性SD大鼠随机分为对照组（C组）、水肿组（I组）、盐酸戊乙奎醚治疗组（P组）。检测6h、12h、24h、48h时各组大鼠脑组织含水量、病理形态;脑组织SOD活性、MDA含量;免疫组化法及RT—PCR法检测AQP4蛋白分布与AQP4mRNA含量。结果：（1）与C组相比,I组、P组脑含水量、MDA含量均升高,同时SOD活性、AQP4蛋白、AQP4mRNA表达均减少（P〈0．01）。与对应时间点P组相比,I组脑含水量、MDA含量均升高,同时SOD活性、AQP4蛋白、AQP4mRNA表达均减少,于24h达高峰,48h仍在较高水平（P〈0．01）。（2）脑组织光镜检查：I组大鼠脑组织损伤严重,P组损伤明显减轻。结论：盐酸戊乙奎醚能在一定程度上可减轻感染所致的脑组织损伤,上调AQP4表达,对脑水肿有一定治疗作用,其机制可能与抗氧化作用有关。     

北京温榆河浮游藻类与水质分析

2006年的监测结果显示,温榆河CODM。BOD5、NH4-N、TP和TN含量大于我国地表水环境质量V类标准的1．3～11．7倍,主要污染物为总氮、氨氯和总磷;五项指标（SS、SD、CODMn,TP、TN）的TSIM值为75．11～119．45,属于富营养型水体。温榆河4个监测断面共检出浮游藻类6门148种,绿藻种类最多（48％）,其次是硅藻（20．9％）、蓝藻（18．2％）,优势种群均为富营养型水体指示种。温榆河浮游藻类密度大,平均为3179．01×10^4 cells／L,绿藻占优势（75．6％）,蓝藻次之（14．6％）。     

脂多糖致感染性脑水肿大鼠星形胶质细胞的活化和凋亡

目的通过观察脂多糖（Lipopolysaccharide,LPS）致大鼠感染性脑水肿后星形胶质细胞的凋亡、活化及iNOS表达情况,探讨在LPS致脑水肿中星形胶质细胞的作用。方法84只雄性SD大鼠,随机分为3组：空白对照纽（C组,n=12）;生理盐水对照纽（S组,n=12）;感染性水肿组（L组,n=60）。感染性脑水肿组又按颈内动脉注射脂多糖后6h、12h、24h、48h、72h分为5个亚组（n=12）。向颈内动脉注射脂多糖LPS150μg（0．15ml）建立大鼠感染性脑水肿模型。采用HE染色、流式细胞检测和免疫纽化染色分别观察脑组织病理改变、星形胶质细胞凋亡、胶质纤维酸性蛋白（GFAP）和iNOS表达情况。结果与C组和S组比较,L组大鼠星形胶质细胞胞体变大、突起增多;细胞内GFAP和iNOS表达增强,12h达高峰,除72h组,其余亚组均有统计学差异（P〈0．05）;各亚组星形胶质细胞凋亡增多（P〈0．05）,24h凋亡最显著。C组和S纽比较无统计学意义（P〉0．05）。结论感染性脑水肿后星形胶质细胞凋亡增加,异常活化,分泌iNOS,参与感染性脑水肿的形成,在脑水肿的发生发展中发挥重要作用。     

未来4年印度将发射10～12颗卫星

印度空间研究组织主席奈尔在卫星用户干扰降低组织（SUIRG）2005年度会议的开幕式上表示：印度正计划在未来4年投资300亿卢比（约6．85亿美元），发射10～12颗近地轨道通信卫星。     

炎性细胞因子与脑梗死的研究进展

脑梗死的病理生理过程中存在着炎症反应和免疫调节,而多种炎性细胞因子参与了再灌注损伤和炎症反应,其中白细胞介素（IL-1β、IL-6、IL-18等）、肿瘤坏死因子（TNF-α）、超敏C反应蛋白（hs-CRP）、基质金属蛋白酶-9（MMP-9）、细胞间黏附分子（ICAM-1）等与炎症反应密切相关。随着分子生物学技术的进展,炎性细胞因子在脑梗死发病机制中的作用更加受到重视。研究炎性细胞因子及炎症反应对缺血性脑损伤的机制可能为脑梗死的防治带来收益。本文就部分炎性细胞因子的生物学活性、理化性质及其在脑缺血损伤中的作用进行了综述。     

Aspirin: recent developments

Aspirin exerts anti-thrombotic action by acetylating and inactivating cyclooxygenase-1, preventing the production of thromboxane A ₂ in platelets. Through this inhibition of platelet function, aspirin is considered as a preventative of ischemic diseases such as coronary and cerebral infarction. However, many studies have revealed that aspirin has other beneficial actions in addition to its anti-platelet activity. For example, aspirin may confer some benefit against colorectal cancer. Here, we discuss the involvement of inflammation in atherosclerosis and how aspirin exerts its beneficial actions in atherosclerotic diseases and cancer. Received 30 September 2007; received after revision 31 October 2007; accepted 6 November 2007     

CT血管造影对脑血管性疾病的临床诊断价值

目的评价64层螺旋CT血管成像对脑血管病的诊断及临床应用价值。方法64层螺旋CT血管成像检查确诊脑血管疾病患者60例,50例在1周内行DSA检查。采用减影方法进行后处理,分别得到VR,MIP,TSMIP图像,利用这三种方法重建图像综合评价脑血管病变。结果①脑动脉狭窄或闭塞者46例,其中36例有DSA对照,98．8％的狭窄或闭塞的脑血管与DSA诊断一致,CT血管成像的敏感性,特异性,准确性分别为100％、98．5％、98．8％;②烟雾病3例,均有DSA对照,表现为单侧或双侧大脑中动脉重度狭窄,远端分支异常增多;③脑动脉瘤患者12例,均有DSA对照,后交通动脉瘤7例,前交通动脉瘤3例,大脑中动脉瘤1例,大脑后动脉瘤1例,CT血管成像与DSA显示一致。结论64层螺旋CT层血管成像能快速,准确地诊断各种脑血管疾病,结合减影处理方法提高了诊断的效率和准确性,为临床提供了全面的信息,可作为脑血管疾病患者的首选诊断方法。     

Effects of sympathetic stimulation on ventricular refractory periods in cats with acute coronary artery ligation

Summary Ventricular refractory periods shorten in the ischemic area following acute coronary artery ligation. Subsequent bilateral sympathetic nerve stimulation reduces disparity in refractory periods across normal, border (peri-ischemic) and ischemic areas.This work was supported by NIH Research Grants HL 19044 and HL 21735, NIH Biomedical Research Support Grant DRR No. S07-05363 and a Grant-in-Aid from the American Heart Association, Florida Affiliate, Broward County Chapter. Dr Gaide is the recipient of NIH New Investigator Research Award HL 27680.     

Consequences of acute ischemia for the electrical and mechanical function of the ventricular myocardium. A brief review

Reduction or interruption of the blood supply to the myocardium leads to marked disturbances of electrical and mechanical function within a few seconds. Electrical dysfunction is characterized by an initial depolarization of the resting membrane, and a decrease of the amplitude, the upstroke velocity and the duration of the action potential. Both depolarization and depression of the action potential are closely associated with intracellular metabolic acidosis. After this initial phase, electrical cell-to-cell uncoupling develops, probably as a consequence of increased cytosolic free [Ca++]. Mechanical dysfunction is characterized by a dissociation of the initial decrease of active force development from the subsequent ischemic contracture. Active force development in acute ischemia is inhibited by the accumulation of ischemic metabolic products (H+, inorganic phosphate (Pi), Mg++) but not by a marked decrease of [ATP]. The subsequent ischemic contracture is probably initiated by release of Ca++ from intracellular stores. This release causes rapid consumption of ATP and the development of rigor within 1-2 minutes.     

Effect of stress on choline acetyltransferase activity of the brain and the adrenal of the rat

Choline acetyltransferase (ChAT) activity was determined in cerebral cortex, hypothalamus, hippocampus, cerebellum, medulla oblongata, midbrain and adrenal gland of rats exposed to acute or chronic stress. The exposure of animals to acute immobilization and cold stress (4°C) for one hour resulted in a significant decline of ChAT activity in all brain regions examined except for the medulla oblongata. Moreover, the exposure to acute stress resulted in significant increase of the same enzyme in the adrenal gland. However, chronic exposure of animals to cold stress (4°C) for 7 days resulted in no significant changes of ChAT activity in all tissues examined except for a decline in the midbrain and an increase in the medulla oblongata. The administration of corticosterone (2.0 mg/kg) 1 h prior to sacrificing caused an effect similar to that of acute stress on ChAT activity in all brain regions except for the hypothalamus and the cerebellum. It was concluded from this experiment that stress-induced changes in the ChAT activity of specific brain regions might be mediated by the adrenal steroids.This work was supported by a grant from the National Aeronautics and Space Administration (NSG 2183 and NAG 2-411), a grant from the National Institutes of Health (NIH RR 0811) and a grant from the Division of Research Resources (NIH grant RR 03020).     

Massive striatal dopamine release in acute cerebral ischemia in rats

Summary Extracellular dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and cerebral blood flow were simultaneously determined using in vivo brain dialysis and a hydrogen clearance method in the striatum of spontaneously hypertensive rats during ischemia and after recirculation. Massive striatal dopamine release was demonstrated in acutely induced ischemic brain.     

Hemodynamic studies in acute venous stasis edema in rats

An increase in venous pressure in the rat tail is known to result in acute edema. Acute venous stasis edema of the rat tail was induced by applying a force-controlled banding of standard tension (200 g) proximally for a period of 6-12 h. The hemodynamic changes of acute venous stasis edema were evaluated using non-invasive plethysmography, fluorescence angiography, computer thermography and invasive radioactive microsphere techniques. It is shown here that reduction of tail circulation to 40% of the control value is followed by prolonged vascular disorder characterized by genesis of reversible edema, increased total blood flow to the tail and decreased local cutaneous blood flow, without affecting the general hemodynamics. The cutaneous circulation (decreased blood flow) seems to be principally involved in the edemogenic response, whereas the deeper vessels (hyperemia) may or may not play a determinant role in acute experimental venous stasis edema in rats.     

Free thyroxine in myocardial infarction

High values for the free thyroxine fraction were found in the serum of 24 patients during the early phase of myocardial infarction. A strong correlation between the free thyroxine fraction and free fatty acids suggests that they compete for protein binding sites. The increase in free thyroxine may have undesirable effects on myocardial oxygen demand during acute myocardial infarction.