Immunoelectron microscopic studies on centromere-kinetochore complexes detached from chromosomes

The centromere-kinetochore complexes of Chinese hamster ovary (CHO) cells were detached and separated from the condensed chromatin by treatment with hydroxyurea and caffeine. By labelling the complex for immunoelectron microscopy (immuno-EM) with a mixture of antibodies against centromere proteins (anti-CENP-A,-B, -C) in some cells, we could demonstrate complete detachment of the complexes. No remnants were left at the bulk of condensed chromatin in these cells. In some mitotic cells complex and chromatin were found side by side. It could be shown that the fine structure of the separated material of the complex differs significantly from that of the rest of chromatin. The complex consists of proteins and DNA. This leads us to suppose that the organization of chromatin in the centromere-kinetochore complex is different.     

Enkephalin mRNA production by cochlear and vestibular efferent neurons in the gerbil brainstem

Summary Preproenkephalin mRNA production by efferent neurons projecting to the gerbil inner ear was assessed using combined in situ hybridization and retrograde labeling with florescent tracers. Virtually all vestibular efferent neurons were positive for preproenkephalin mRNA. Of the cochlear efferents, one-half of the medial olivocochlear neurons were positive for enkephalin. All lateral olivocochlear neurons were negative for enkephalin. The results suggest that there are two, biochemically distinct subpopulations of medial olivocochlear efferents in the gerbil. Offprint requests to: Division of Otolaryngology, ENT, V-112C     

基于系统输出分布的智能控制

提出了文题所述的控制策略,依据输出分布曲线的特征变量选取方法和依据该项信息的规则控制系统。仿真研究得到了满意的结果。在一个实验性二元精馏塔上用IBM-PC进行试验亦获成功。本法对具有非线性特性的分布参数对象,较常规控制策略有明显的优越性。     

多复指数模型及其在EEG数据分析中的应用

由头皮上电极所记录下的EEG信号是大脑中各种电活动,尤其是神经元电活动,互相耦合而产生的电位变化的整体反映。有一种看法认为,表面看来随机、无规则的EEG信号,实际上它的变化只是由少量几个动力学参量控制着的非线性过程。根据这个假定,我们提出使用多复指数(MCE)模型来描述EEG信号的想法。文中首先简要地介绍了用来估计时序信号MCE模型参数的非调和Fourier展开算法(NHFE)的基本思想。然后,对一个叠加有白噪声、具有4个频率成分的模拟信号,用NHFE算法估计出其MCE模型参数,并把所得的结果与用经典的周期图谱分析方法、AR模型谱分析方法所得到的信号频谱作了比较。结果表明,在SNR高的条件下,NHFE算法所估计出的模型参数能更客观地反映信号的固有特性。基于目前的有关EEG形成的假设,应用MCE模型来描述EEG将更能反映出其特征。因此,我们对MCE模型及其参数在EEG数据分析中的几种可能应用作了初步尝试。这些应用包括:EEG信号段(或一段诱发电位,或一段事件关联电位)的特征参数的提取,这些特征参数包括优势频率值、独立的频率成分个数、幅度值、正负衰减指数的个数、频带宽度与幅度乘积(能量);EEG的频率调制特性的粗略描述等。从而看到了用通常信号分析方法所看不到的EEG信号中所反映的大脑活动的变化。由于用MCE模型及其参数来描述EEG的方法更符合目前关于大脑非线性动力学行为的假设,所以这一方法将是表示EEG信号的有效途径之一。另外,MCE模型方法在EEG信号的模拟研究与数据压缩等方面也将是有用的。文中还讨论了NHFE算法应用中的一些问题。     

Dynamic response of the occipito-atlanto-axial (C0-C1-C2) complex in right axial rotation.

The torque-angular deformation in right axial rotation until failure of the ligamentous occipito-atlanto-axial complex subjected to variable loading rate (dynamic) axial torque was characterized using a biaxial MTS system. A special fixture and gear box that permitted right axial rotation of the specimen until failure without imposing any additional constraints were used to obtain the data. The specimens were divided into three groups and tested until failure at three different dynamic loading rates: 50, 100, and 400 degrees/s. A previous study by the authors provided data for quasi-static (4 degrees/s) loading conditions. The torque versus rotation curves can be divided into two straight regions and two transition zones. The plots clearly indicated that at loading rates higher than 4 degrees/s, the specimens became stiffer in the region of steadily increasing resistance prior to failure. The increase in stiffness was maximum at 100 degrees/s. The stiffness decreased somewhat at 400 degrees/s in comparison with 100 degrees/s, but this decrease was not significant. The resulting torque-right axial rotation curves were also examined to estimate the magnitude of maximum resistance (torque) and the corresponding angular rotation value. The average maximum resistance torque increased from 13.6 Nm at 4 degrees/s to 27.8 Nm at 100 degrees/s. The corresponding right angular rotation data (65-78 degrees), however, did not show any significant variation with loading rate. Posttest dissection of the specimens indicated that the type of injury observed was related to the rate of axial loading imposed on a specimen during testing.(ABSTRACT TRUNCATED AT 250 WORDS)     

Thrombosis triggered by severe arterial lesions is inhibited by oral administration of a glycoprotein IIb/IIIa antagonist

Platelet aggregation and thrombosis play an important role in the onset of acute coronary events. Regardless of the stimulus for activation, platelet thrombus formation is ultimately regulated through the IIb/IIIa receptor complex. The effects of oral administration of xemilofiban, a non-peptide mimetic of the RGDF sequence of the IIb/IIIa receptor complex, on thrombus formation were evaluated in a canine model. Xemilofiban significantly reduced platelet deposition on severely damaged arterial wall. Platelet deposition was reduced at both low (13 ± 1 from 56 ± 18 × 10⁶ platelets cm⁻²; P  < 0.05) and high (23 ± 2 from 111 ± 21 × 10⁶ platelets cm⁻²; P  < 0.01) shear rates. Platelet deposition was reduced to a monolayer as seen by electron microscopy (platelet–vessel wall interaction). Therefore, the availability of an orally active IIb/IIIa antagonist for chronic use may have significant value in preventing thrombus formation in those clinical situations associated with severe arterial injury, such as atherosclerotic plaque disruption.     

病毒性心肌炎及扩张型心肌病患者心内膜心肌活检标本中免疫球蛋白的检测

对病理学确诊的25例病毒性心肌炎（VMC）和10例扩张型心肌病（DCM）患者心内膜心肌活检标本，运用ABC技术，进行了免疫球蛋白IgG、IgM、IgA和补体C3的检测。结果：20例VMC和9例DCM的标本中，发现了IgG和IgM的沉积，主要分布于心肌肌膜和毛细血管内皮，IgG的肌膜沉积与同步做的病理切片中观察到的心肌细胞坏死和炎性细胞浸润有病理形态学联系。两组患者中均未发现IgA和C3沉积。结果显示，IgG是参与VMC和DCM心肌损伤的主要免疫球蛋白，心肌病变与抗体诱导的免疫反应有关。     

基于多分辨率分析的心电图QRS波检测

从多分辨率分析出发，构造出一个用于心电图R波检测的滤波器，并在此滤波器的基础上提出了一种新的R波检测算法。本文详细论述了滤波器的构造方法和新的R波检测算法的原理及在实现中采用的一些策略，经MIT-BIH标准心律失常数据库验证，该算法对于各种干扰尤其是肌电干扰具有很强的抑制能力。算法实现简单，计算量小，在ECG信号的脱机和实时处理程序中均可使用。     

腹腔镜与开腹胆囊切除胃肠压力变化的临床研究

目的 :从胃肠道压力变化的角度探讨腹腔镜与开腹胆囊切除对胃肠运动功能的影响。方法 :腹腔镜胆囊切除 30例 (男 6例 ,女 2 4例 ,4 7± 4岁 ) ,开腹胆囊切除 30例 (男 9例 ,女 2 1例 ,4 7± 7岁 ) ,分别于手术前 1d行胃电图描记 ,记录术后 3、2 4、4 8、72h胃电图及监测胃窦、十二指肠和空肠压力 (移行性运动复合波 ,MMCⅢ )。结果 :(1)手术前腹腔镜和开腹胆囊切除患者胃电频率差异无显著性 (P >0 .0 5 ) ;(2 )腹腔镜胆囊切除组术后 3、2 4h正常波所占百分比低于术前 ,但差异无显著性 (P >0 .0 5 ) ,术后 4 8h恢复正常 ;(3)开腹胆囊切除组术后起 3h正常波所占百分比明显低于术前 ,差异有显著性 (P <0 .0 1) ,术后 2 4、4 8h正常波的百分比与术前差异无显著性 ,术后 72h恢复正常 ;(4) 2组患者术后胃窦、十二指肠及空肠压力低于健康人群 (P<0 .0 5 ) ;(5 ) 2组胃窦部收缩压力及收缩曲线下面积术后第 1、2、3d较术后 3h明显升高 (P <0 .0 5 ) ,且随时间延长有逐渐增大的趋势 ,腹腔镜组术后 72h恢复正常 ,十二指肠及空肠术后 3d内无明显变化 ;(6 ) 2组间胃电频率 ,胃窦部、十二指肠及空肠压力变化差异无显著性 (P >0 .0 5 ) ,但显示有差别。结论 :腹腔镜与开腹胆囊切除术均可引起胃电频率及胃肠压力变化 ,开