SCHWANN CELLS AND THE REGROWTH OF AXONS IN THE MAMMALIAN CNS: A REVIEW OF TRANSPLANTATION STUDIES IN THE RAT VISUAL SYSTEM

1. We have used peripheral nerve transplants or cultured Schwann cells grafted in association with different types of polymer to study axonal regrowth in the rat visual system. In some instances the glia were co-grafted with fetal tectal tissue. 2. The studies have two main aims: (i) to determine whether retinal axons can be induced to regrow at a site distant from their cell soma, that is, after damage to the brachial region of the optic tract; (ii) to determine whether retinal axons exposed to Schwann cells retain the ability to recognize their appropriate target neurons in CNS tissue. 3. In brachial lesion studies, Schwann cells were placed in the lesion site in association with nitrocellulose papers, within polycarbonate tubes in the presence or absence of a supporting extracellular matrix (ECM), or within polymer hydrogel scaffolds. Autologous sciatic nerve grafts were also used. Immuno-histochemical studies revealed the presence of regenerating axons within all polymer bridges. Regrowth of retinal axons was also seen, however, growth was not extensive and was limited to the proximal 1–1.5 mm of the implants. 4. In target innervation experiments, two surgical paradigms were developed. In one experiment, a segment of sciatic nerve was autografted onto the transected optic nerve in adult rats and the distal end of each graft was placed adjacent to fetal tectal (target) tissue implanted into the frontal cortex. To date, we have not been able to demonstrate selective recognition of target regions within tectal transplants by retinal axons exiting the sciatic nerve implants. 5. In the second experiment, Schwann cells were mixed with fetal tectal cells and co-grafted to the midbrain of newborn host rats. Schwann cells altered the characteristic pattern of host retinal growth into tectal grafts; in some cases axons were induced to grow away from appropriate target areas by nearby co-grafted Schwann cells. 6. In summary, Schwann cell/polymer scaffolds may provide a useful way of promoting the regrowth of damaged axons in the CNS, however: (i) in adults, at least, their effectiveness is reduced if they are located at a distance from the cell bodies giving rise to regenerating axons; (ii) in some circumstances exposure to a peripheral glial environment may affect the capacity of regenerating axons to recognize appropriate target cells in the CNS neuropil.     

4℃保存外周血造血干细胞动态观察

本文对4℃条件下不同时间保存后的外周血造血干细胞(peripheral bloodhematopoietic stem cells,PBHSC)数进行了动态观察。在本实验中以定向造血祖细胞(CFU-GM)作为观察PBHSC的指标。结果表明:随着保存时间的延长,PBHSC集落数逐渐下降;0小时与24小时保存后的干细胞数无显著差异;24小时与48、72、96、120小时保存后的干细胞数有高度显著差异;48小时与72、96、120小时保存后的干细胞数无显著差异。同时发现,红细胞的存在有利于PBHSC的4℃保存。     

Aldose reductase inhibition with imirestat — effects on impulse conduction and insulin-stimulation of Na+/K+-adenosine triphosphatase activity in sciatic nerves of streptozotocin-diabetic rats

Summary This study describes reduced motor nerve conduction velocity and increased resistance to hypoxia-induced conduction failure in sciatic nerves of rats after four weeks of streptozotocin-induced diabetes (both effects were significant at p <0.05). These changes occurred in the absence of any deficit in the steady-state ouabain-sensitive adenosine triphosphatase (ATPase) activity of sciatic nerve endoneurial homogenates. The addition of 10 nmol/l insulin to endoneurial homogenates from control animals resulted in a 34% increase in ouabain-sensitive ATPase activity and a 19% reduction in ouabain-insensitive ATPase activity (both p <0.01). This stimulation of ouabain-sensitive ATPase activity by insulin did not occur in homogenates from diabetic rats. Treating diabetic rats daily with the aldose reductase inhibitor, imirestat (1 mg/kg) improved nerve conduction velocity (p <0.05) but was without effect upon the resistance to hypoxic conduction blockade or the deficit in insulin-stimulated oubain-sensitive ATPase activity. These data suggest that in streptozotocin-diabetic rats the functional disorders of reduced motor nerve conduction velocity and increased resistance to hypoxic conduction blockade do not share a common aetiology and that impaired nerve conduction is not related to reduced maximal potential oubain-sensitive ATPase activity.     

Assessment of exposure to arsenic among smelter workers: A five-year follow-up

In a group of 43 smelter workers exposed to inorganic arsenic dust for 13-45 years, nerve conduction velocities (NCVs) were significantly lower in two peripheral nerves as compared with matching referents. With multivariate data analysis, a significant negative correlation was found between cumulative absorption of arsenic and NCV in four examined nerves and the sural amplitude. Clinical symptoms of neuropathy and other symptoms related to arsenic exposure were moderate, though the difference between the groups was significant. The mean total absorption of arsenic was calculated to be less than 5 g, and the maximal absorption about 20 g. These data indicate that the adverse effect of arsenic on the peripheral nerves is dependent on long-term exposure rather than on short-term fluctuations in exposure levels. © 1994 Wiley-Liss, Inc.     

2型糖尿病患者外周血白细胞iNOSmRNA表达的变化及意义

目的研究2型糖尿病DM患者外周血白细胞中iNOSmRNA表达的变化及其与糖尿病肾病DN发生、发展的关系。方法101例2型DM患者,根据尿微量白蛋白排泄率和血肌酐水平分为单纯DM组和不同的DN组,用原位杂交法检测外周血白细胞iNOSmRNA表达的阳性细胞的百分率,并与21例健康体检者进行比较。结果早期DN组白细胞iNOSmRNA表达的百分率明显高于对照组、DM组及晚期DN组(P<0.001)。结论外周血白细胞iNOSmRNA表达的变化参与了DN的发生、发展。     

二子合剂对糖尿病大鼠肾脏的保护作用

目的：探讨富含木脂素成分的中药牛蒡子、五味子组成的二子合剂对糖尿病大鼠肾脏的保护作用。方法：将SD大鼠建成链脲佐菌素诱导的糖尿病模型，设正常对照组、模型对照组、苯那普利治疗组、二子合剂大剂量治疗组及小剂量治疗组．4周后检测血糖、24h尿量、尿蛋白总量、尿白蛋白总量、血胆固醇、尿ET-1、TNF-α及肾组织病理变化。结果：与模型对照组相比，苯那普利组及二子合剂大剂量治疗组各项检测指标均有改善，两疗效近似。二子合剂小剂量治疗组仅见尿白蛋白总量及毛细血管襻面密度有减少。结论：牛蒡子、五味子合剂对糖尿病肾脏损害有一定的保护作用，其作用与剂量有相关性。     

多平面重建对支气管血管连接引起肿瘤切迹的检出

目的　从病理角度认识支气管血管切迹征 ,探讨多平面重建 (MPR)对该征检出的作用。方法　①观察病理证实的周围型小肺癌 91例 ,良性结节 5 5例。以及 9例周围型小肺癌 ,2例良性结节术后改良Heitzman法充气固定肺叶制成病理大切片 ,对良恶性支气管血管连接进行对比分析。②对恶性支气管血管连接 2 0例 ,良性 13例行MPR ,考察MPR显示切迹征的作用。结果　①支气管血管切迹征对恶性者特异性为 95 .2 %。②恶性支气管血管连接在MPR的切迹征检出率为 70 % ,与横断扫描之间有显著差异。结论　切迹征对于恶性支气管血管连接有高特异性诊断价值。MPR配合多层螺旋CT能提高此征检出率     

视网膜特异性表达人血管内皮生长因子 基因载体的构建

目的构建在视网膜组织特异性表达的人血管内皮生长因子（VEGF）₁₆₅基因。方法用聚合酶链反应(PCR)方法从BLAB/C鼠全基因组扩增能在视网膜组织特异性表达的rho启动子，经限制性内切酶纯化后克隆于质粒pcDNA^3.1+-VEGF₁₆₅中，建立重组质粒pcDNA^3.1+-rho-VEGF₁₆₅，通过限制性内切酶酶切分析及PCR鉴定筛选出正确重组质粒pcDNA^3.1+-rho-VEGF₁₆₅,由jetPEI介导转染人视网膜色素上皮细胞和人脐静脉内皮细胞，并通过免疫组织化学染色以及绘制细胞生长曲线检测在人视网膜色素上皮细胞和人脐静脉内皮细胞中VEGF蛋白的表达。结果在人视网膜色素上皮细胞中，重组质粒pcDNA^3.1+-rho-VEGF₁₆₅比质粒pcDNA^3.1+-rho-VEGF₁₆₅的VEGF蛋白表达强，在人脐静脉内皮细胞，两者的表达量无明显差别。结论pcDNA^3.1+-rho-VEGF₁₆₅载体的构建为进一步研究VEGF在视网膜新生血管形成中的致病机理提供基础材料，并为进一步建立视网膜特异性表达VEGF转基因鼠模型建立了基础。(中华眼底病杂志,2005,21:106-109)     

TOCP染毒母鸡的神经电生理研究

对TOCP染毒母鸡进行为期7周的神经电生理监测,结果表明,TOCP主要影响远端周围神经,导致坐骨神经远端MCV和SCV减慢及腓肠肌EMG失神经样改变,而胫后神经H反射及重复电刺激无明显异常。     

中药泡洗治疗糖尿病足90例疗效分析

目的为了观察中药泡洗对糖尿病足的疗效。方法对90例糖尿病足患者用中药（方剂组成：桃仁、红花、桂枝、没药、乳香、花椒、川芎等各10g）水煎制后分为2袋各300ml配合足浴仪泡洗，2次，d，30min／次，10d为1疗程。结果全组90例患者显效66例，有效24例，总有效率100％。结论中药泡洗治疗糖尿病足疗效确切。