间隙连接在鸡胚水晶体发育中的作用

初步报道已揭示，单克隆抗体ＮＤ６可影响鸡胚水晶体的发育，使之明显增大．ＮＤ６是一种被认为专一于膜蛋白ＭＰ２６细胞外侧段的单抗．ＭＰ２６已被认为是水晶体纤维细胞间隙连接的成份．因此，ＮＤ６很可能可阻断水晶体纤维细胞间隙连接的形成．本人试图用定量显微镜技术证实ＮＤ６对水晶体发育的影响与间隙连接数量减少之间的相关性。注射ＮＤ６于２０期鸡胚的右眼；同胚未注射的左眼作为对照．培养２４ｈ后周定，然后作下列三种处理：（１）测量整体水晶体的大小；（２）制备水晶体超薄切片，并统计间隙连接数量；（３）制备鸡胚头部的连续石蜡切片，并统计水晶体纤维细胞的数量．实验结果指出，在ＮＤ６处理２４ｈ，水晶体大小及纤维细胞数量均比对照组明显增大（表１，Ｐ＜０．０１或０．００１）；而间隙连接数量则比对照组明显减少（表２），Ｐ＜０．００１）．这表明，水晶体的增大及纤维细胞的增多是由间隙连接的减少所引起．这些结果证实，间隙连接在鸡胚水晶体的发育中起重要作用．     

Neuromuscular synaptogenesis: clustering of acetylcholine receptors revisited

Clustering of neurotransmitter receptors in the postsynaptic membrane is critical for efficient synaptic transmission. During neuromuscular synaptogenesis, clustering of acetylcholine receptors (AChRs) is an early sign of postsynaptic differentiation. Recent studies have revealed that the earliest AChR clusters can form in the muscle independent of motorneurons. Neurally released agrin, acting through the muscle-specific kinase MuSK and rapsyn, then causes further clustering and localization of clusters underneath the nerve terminal. AChRs themselves are required for agrin-induced clustering of several postsynaptic proteins, most notably rapsyn. Once formed, AChR clusters are stabilized by several tyrosine kinases and by components of the dystrophin/utrophin glycoprotein complex, some of which also direct postnatal synaptic maturation such as formation of postjunctional folds. This review summarizes these recent results about AChR clustering, which indicate that early clustering can occur in the absence of nerves, that AChRs play an active role in the clustering process and that partly different mechanisms direct formation versus stabilization of AChR clusters. Received 10 April 2002; received after revision 4 June 2002; accepted 10 June 2002     

螺旋CT三维重建及多平面成像对胸腰段脊柱爆裂骨折的诊断价值探讨

目的：探讨螺旋CT三维重建（CT3D）及多平面重建（MPR）对胸腰段脊柱爆裂骨折诊断的优缺点及临床应用价值。方法分析53例胸腰段脊柱爆裂骨折病例。分别行X线平片，CT及螺旋CT三维重建、多平面重建检查及技术处理。结果：CT对椎体中后柱骨折的显示有明显优越性，而三维重建及多平面重建不仅能具体、直观、形象显示骨折情况，而且对脊髓、神经根损伤的显示价值清楚。结论平片诊断爆裂骨折需与单纯压缩骨折鉴别，明确诊断需CT证实，螺旋CT3D和MPR对诊断及了解椎管内损伤有很好的应用价值。     

螺旋CT三维重建及多平面成像对胸腰段脊柱爆裂骨折的诊断价值探讨

目的探讨螺旋CT三维重建(CT3D)及多平面重建(MPR)对胸腰段脊柱爆裂骨折诊断的优缺点及临床应用价值。方法分析53例胸腰段脊柱爆裂骨折病例。分别行X线平片,CT及螺旋CT三维重建、多平面重建检查及技术处理。结果CT对椎体中后柱骨折的显示有明显优越性,而三维重建及多平面重建不仅能具体、直观、形象显示骨折情况,而且对脊髓、神经根损伤的显示价值清楚。结论平片诊断爆裂骨折需与单纯压缩骨折鉴别,明确诊断需CT证实,螺旋CT3D和MPR对诊断及了解椎管内损伤有很好的应用价值。     

f波超导体/绝缘层/f波超导体结中势垒散射对直流Josephson电流的影响

通过计算界面势垒散射强度对直流Josephson电流的影响,研究了f波超导体/绝缘层/f波超导体结的直流Josephson电流与温度T和结两侧晶轴方位角之间的关系.我们发现:f波超导体/绝缘层/f波超导体结界面的势垒强度总是抑制结中准粒子的Andreev反射,降低流过f波超导体/绝缘层/f波超导体结的直流Josephson电流.当结两边晶轴方位角相同时,Josephson电流的振荡周期是2π;特别地,当结两边晶轴方位角不同时,其振荡周期不再是2π,而是会随着势垒强度的增大,振荡周期变小.     

控制爆破之烟囱拆除

本文针对烟囱的控制爆破拆除，论述了控制爆破的原理，阐明了缺口位子，缺口参数和爆破参数的确定方法，探讨了爆破危害与防治。     

一种早期诊断皮下肿瘤的新方法

提出了一种采用微带六端口进行早期诊断皮下肿瘤的新方法 ,并研制了原理性的微带六端口皮下肿瘤早期诊断仪 .     

管网结点处两相流相分离流动可视化在线检测实验研究

采用在线式可视化图象技术，对管网中的特征结构元件－－等直径水平Ｔ形分叉管（Ｄ＝３５ｍｍ）的空气－水泡状流，弹状流，分层流的相分离现象进行了实验研究，发现并定义了“新型完全相分离现象”，即在特定工况下，入流的气相流体将完全从直管出口流出，另外通过可视化研究对“压力波反馈效应”及“分叉管中气相重组现象”进行了分析和探讨；将入口质量流量、入口干度及支管质量抽走率对两相分离率的影响作了比较和分析。     

Neurotrophic regulation of synapse development and plasticity

Neurotrophic factors are traditionally thought to be secretory proteins that regulate long-tern survival and differe, ntiation of neurons. Recent studies have revealed a previously unexpected role for these factors in synaptie de velopment ami plasticity in diverse neuronal populations. Here we review experimeuts carried oul in our own laboratory in the last few years.. We have made two important discoveries.First,we were among the first to report that brain-derived. neurotrophie faclor (BDNF) facilitates hippocampal hmg-term potentiation (LTP), a form of synaptic plaslicity believed to be involved in learning and memory. BDNF modulates LTP al CAI synapses by enhaneing synaptic responses to high frequency, tetanic slimulalion. This is achieved primafily by facilitating synaptie vesicle doeking, possibly due to an in crease in the levels of the vesicle prolein synaptobrevin and synaptoplysin in the nerve terminals. Gene knockout study demonstrates thai the effects of BDNF are primarily mediated through presynaptic mechanisms. Second, we demonstrated a form of long-term, neurotrophin-mediated synaptic regulation. We showed that long-term treatment of the neuromuscu lar synapses with neurotrophin-3 (NT3) resulted in an enhancement of both spontaneous and evoked synaptic currcuts, as well as profound changes in thc number of synaptic varicosities and syuaptic vesicle proteins in motoneurons, all of which are indicative of more mature synapses. Our current work addresses the following issues:(i) activity-dependent trafficking of neurotrophin receptors, and its role in synapse-specific modulation; (ii) signal transduction mechanisms medialing the acute enhancement of synaplic transmission by neurotrophins; (iii) acute and long-tenn synaptie actions of the GDNF family; (iv) role of BDNF in late-phase LTP and in the development of hippocampal circuit.     

Intercellular dye-coupling in intestinal smooth muscle. Are gap junctions required for intercellular coupling?

Summary The dye Lucifer Yellow was injected into single smooth muscle cells in the guinea pig small intestine in order to study intercellular coupling. Dye-coupling was observed in both the circular and longitudinal muscle layers and was markedly reduced when the intercellular pH was lowered. These results suggest the presence of gap junctions among intestinal muscle cells, but are inconsistent with previous ultrastructural studies that failed to demonstrate such junctions in the longitudinal muscle.