Differences in cardiac myosin light chain LC1 among human,monkey and sheep

Summary The atrial and ventricular myosin light chains of human, monkey and sheep hearts were compared by dodecylsulfate polyacrylamide gel electrophoresis. The atrial light chain 2 and ventricular light chain 2 are similar among these mammals. However, the atrial light chain 1 of monkey has different electrophoretic mobility from those of human and sheep. The monkey ventricular light chain 1 has same mobility as that of sheep but different from that of human.Acknowledgments. This work was supported by MRC of Canada No. MA-8559. Dr G. Jackowski is a scholar of the Medical Research Council of Canada, and is the author to whom all correspondence should be addressed.     

Tetrodotoxin slightly shortens action potential duration in ventricular but not in atrial heart muscle

Summary Tetrodotoxin (TTX), at concentrations significantly decreasing maximal upstroke velocity (dV/dt_max) of the action potential, exerted variable effects on action potential duration (APD) in different myocardial preparations. APD was virtually unchanged by tetrodotoxin in the guinea pig atrium, but slightly shortened in the guinea pig ventricle at maximally effective concentrations. In the human ventricle, both dV/dt_max and APD were reduced in the same concentration range of TTX. These results suggest that a TTX-sensitive sodium current significantly contributes to the repolarization phase of the action potential in ventricular but not in atrial heart muscle.Supported by the Deutsche Forschungsgemeinschaft (Na 105/5-5) and by the Fonds der Chemischen Industrie. Author to whom reprint requests should be addressed. We thank Mrs. Johanna Rupp for expert technical help. We also thank one referee for suggesting the experiments depicted in figure 4.     

左心室射血时间参考值与地理环境的回归分析

为探讨中国健康成年人左心室射血时间参考值的地理分布规律,给制定左心室射血时间参考值的统一标准和临床诊断提供参考依据.收集了中国64个单位测定的9185例健康成年人左心室射血时间参考值,运用相关分析法分析左心室射血时间参考值与海拔高度(X1)、年日照时数(X2)、年平均气温(X3)、年平均相对湿度(X4)、年降水量(X5)、气温年较差(X6)、年平均风速(X7)7个地理环境指标之间的相关性;然后选取海拔高度(X1)、年平均气温(X3)、年平均相对湿度(X4)3个与左心室射血时间参考值相关性显著的地理环境指标作为解释变量,运用回归分析的方法建立模型,分析成年人左心室射血时间参考值与所选取地理指标之间的关系.结果表明,健康成年人左心室射血时间参考值与地理指标之间存在相关关系,利用回归分析法推导出一个线性回归方程:∧Y=309.3017+0.0055X1+0.0820X3-0.1940X4±9.0071.通过克里格(Kriging)插值法精确内插出中国成年人左心室射血时间参考值的地理分布图.利用某地区地理环境数据,可用此模型估算该地区健康成年人左心室射血时间参考值.     

Mechanism of neurogenesis in adult avian brain

Summary Adult neurogenesis in birds offers unique opportunities to study basic questions addressing the birth, migration and differentiation of neurons. Neurons in adult canaries originate from discrete proliferative regions on the walls of the lateral ventricles. They migrate away from their site of birth, initially at high rates, along the processes of radial cells. The rates of dispersal diminish as the young neurons invade regions devoid of radial fibers, probably under the guidance of other cues. The discrete sites of birth in the ventricular zone generate neurons that end up differentiating throughout the telencephelon. New neurons may become interneurons or projection neurons; the latter connect two song control nuclei between neostriatum and archistriatum. Radial cells, that in mammals disappear as neurogenesis comes to an end, persist in the adult avian brain. The presence of radial cells may be key to adult neurogenesis. Not only do they serve as guides for initial dispersal, they also divide and may be the progenitors of new neurons.     

Effect of La^3＋ on myocardiac potassium channels revealed by patch-clamp technique

The effect of La^3 on potassium channels in rat ventricular myocytes was investigated using the whole-cell patch-clamp recording mode. The Ca^2 -independent voltage-activated outward K~ current was activated by the depolar-izing pulse in enzymatically isolated rat ventricular myocytes. After addition of different concentrations La^3 to the bath solution, the outward K^ current was depressed gradually. The inhibition effect was in a concentration-dependent manner. The phenomena of the outward K^ current, being themain repolarizing current suppressed by La^3 , suggest that the effect of lanthanides on myocardial function should be exploited further.     

洛汀新对原发性高血压左室肥厚并发室性心律失常影响研究

选择 8 6例原发性高血压的患者 ,按心脏超声心动图分为左室肥厚组 (A组 )和非左室肥厚组 (B组 )进行比较室性心律失常的发生率 ,并采用血管紧张素转换酶抑制剂洛汀新进行治疗观察 .结果表明 :A组室性心律失常发生率与B组有极显著性差异 (P <0 .0 0 1) ,而治疗前与治疗后室性心律失常的检出率及Lown’s分级危险性为显著性差异 (P <0 .0 1) .洛汀新具有较好的应用前景     

信号叠加技术在心室晚电位信号检测中的应用

心室晚电位（ＶＬＰ）怀心肌死及室性心动过速是密切相关的，所以ＶＬＰ的无创检测可为临床诊断提供有效的依据，但ＶＬＰ信号常被噪声所淹没，直接检测非常困难，利用信号叠加技术处理ＥＣＧ信号，可有效消除噪声，使ＶＬＰ信号能准确地检出，在信号叠加过程中，同步参考点位置的确定至关重要本文介绍了利用截取固定度确定同步参考点的方法。     

Prediction of ventricular fibrillation based on nonlinear multi-parameter

Ventricular fibrillation (VF) caused by myocardial ischemia is one of the leading factors of death attributed to cardiovascular diseases. It is particularly significant to predict VF and gain valuable time for clinic therapy. Five dogs are taken as the research objects and a VF model is introduced. The nonlinear characteristics of the ECGs before and after VF are investigated with nonlinear multi-parameter analysis methods, Gaussian kernel (GK) correlation estimation algorithm and Lyapunov exponent estimation algorithm. Correlation entropy h2 is also presented. The results indicate that there are three parameters which will change at the same time with the conditions of myocardial ischemia,and any changes of a single parameter may be caused by other factors and mislead the judgment. Multi-parameter analysis is more reliable to reveal the heart conditions, and to predict VF without misjudgments.     

ASD、VSD和MS患者SOD活力的研究

目的：检测房间隔缺损（ＡＳＤ）、室间隔缺损（ＶＳＤ）和二尖瓣狭窄（ＭＳ）的患者红细胞中ＳＯＤ活力,分析术后ＳＯＤ活力的变化。方法：应用四氮唑蓝法（ＮＢＴ法）。结果：ＡＳＤ、ＶＳＤ和ＭＳ患者红细胞中ＳＯＤ活力明显低于正常人,术后可见ＳＯＤ活力逐步提高,患者年龄愈小,ＳＯＤ活力增加幅度愈大。结论：ＡＳＤ、ＶＳＤ和ＭＳ患者术后可使ＳＯＤ活力增加,有利于保护心脏正常功能。     

急性心肌梗塞患者最大QT_c间期、QT离散度与恶性心律失常的关系

为探讨急性心肌梗塞（ＡＭＩ）患者最大校正ＱＴ间期（ＱＴｃｍａｘ）、ＱＴ离散度（ＱＴｄ）和ＱＴｃ离散度（ＱＴｃｄ）与恶性心律失常的关系,回顾性分析了４７例ＡＭＩ患者（分为恶性心律失常组１４例和无室性心律失常组３３例）发病３ｄ内的心电图,并以５０例健康人作对照。结果显示：两组ＡＭＩ患者的ＱＴｃｍａｘ、ＱＴｄ和ＱＴｃｄ均显著大于对照组（Ｐ＜０００１）,而恶性心律失常组的上述指标比无室性心律失常组显著增大（Ｐ＜００５～０．００１）。提示ＱＴｃｍａｘ延长和ＱＴｄ、ＱＴｃｄ增大与ＡＭＩ患者恶性心律失常的发生密切相关,测定上述指标对ＡＭＩ近期预后的判断有一定价值。