Localization and characterization of epidermal growth-factor receptors in the developing rat medial septal area in culture

The presence and binding properties of epidermal growth-factor receptors (EGF-Rs) in different cell types purified from the rat medial septal area in culture were investigated. We report that astrocytes, oligodendrocytes and neurons from this area possess EGF-Rs while microglia do not. EGF-binding sites are detectable on astrocytes derived from the medial septum of both embryonic and neonatal rats. Scatchard analysis of the data for astrocytes from the fetal rats show that EGF specifically binds to both high- (K_d = 7.21 × 10⁻¹⁰ M, B_max = 3602 receptors/cell) and low-affinity (K_d = 3.99 × 10⁻⁸ 10⁻⁸ M, B_max = 6,265 receptors/cell) receptors on these cells. On the other hand, astrocytes purified from neonatal tissue possess a greater number of high-affinity receptors (B_max = 10,938 receptors/cell) when compared with the embryonic astroglia. With time in culture, the number of both types of receptors on neonatal astrocytes decreases. Oligodendrocytes also possess high- and low-affinity EGF-Rs with dissociation constants of 3.25 × 10⁻¹⁰ M and 3.85 × 10⁻⁸ M, respectively. The number of receptors on oligodendrocytes is significantly lower than those on neonatal astrocytes (B_max = 1185 and 25,081 receptors/cell for high- and low-affinity binding sites, respectively). Finally, neurons from this area also exhibit two different EGF-R types with dissociation constants similar to those described for astrocytes. As the number of receptors/neuron (B_max = 136 and 1159 receptors/cell for high- and low-affinity binding sites, respectively) appears to be extremely low, it is possible that EGF specifically binds only to a subpopulation of neurons from this area. These studies demonstrate which cell types in the developing medial sepal area posses EGF-Rs and provide a detailed characterization of these binding sites. These EGF-R-bearing cells may be potential targets for this growth factor or for transforming growth factor α in this brain area.     

高压氧对大鼠局灶性脑缺血再灌注时神经元特异性烯醇化酶的影响

目的研究高压氧(HBO)对大鼠局灶性脑缺血再灌注(IR)时．大鼠脑梗塞体积．脑组织病理改变及神经元特异性烯醇化酶(NSE)含量的影响。方法用线栓法制备阻断大脑中动脉(MCA)的局灶性脑IR模型。Wistar大鼠30只，随机分为5组：正常对照组(N组n=-6)，缺血再灌注2h 常压空气组(Rt组,n=-6)，缺血再灌注24h 常压空气组(R2组，n=-6)，缺血再灌注2h HBO组(H1组，n=-6)，缺血再灌注24h HBO组(H2组，n=-6)。R1、R2、H1、H2组缺血时间均为2h。R1、R2组暴露于常压空气，H1、H2组暴露于2．5MPa氧气。病理切片用HE染色，用Swanson方法测定脑梗塞体积，用酶联免疫法测定NSE含量。结果H1、H2组与R1、R2组相比，神经元缺血性损害较轻，脑梗塞体积缩小，NSE含量明显下降，差异有统计学意义。结论HBO能减轻缺血性脑损害，保护脑组织。     

丙烯酰胺对大鼠胚胎神经细胞分化的影响

用细胞微团培养法研究丙烯酰胺对大鼠胚胎神经细胞分化的影响。结果表明，当细胞培养物中丙烯酰胺浓度大于６０μｇ／ｍｌ时，可明显抑制细胞分化，表现为细胞集落数目减少，细胞表面突起和集落间神经纤维束减少，细胞形态改变。其半数分化抑制浓度（ＩＣｄ５０）为７５μｇ／ｍｌ，半数存活抑制浓度（ＩＣｖ５０）为９０μｇ／ｍｌ，两者较为接近。认为丙烯酰胺对细胞分化的抑制作用可能被其细胞毒作用所掩盖，其致畸作用不可忽视。     

脑内缝隙连接

缝隙连接普遍存在于动物组织中，具有重要的生理功能。近年来，由于分子生物学等技术的应用，对许多组织的缝隙连接蛋白的特性及其功能的研究取得了很大进展。本文重点介绍脑内缝隙连接蛋白的类型，分布及其生物物理学和药理学特性，并阐述胶质细胞之间、神经元之间缝隙连接的作用，以及缝隙连接与脑发育和癫痫等神经系统疾病的关系。     

尼氏小体染色方法的改进及其在神经病理学研究中的应用

组织或细胞的染色在病理学诊断、科学研究和教学工作中,都具有非常重要的意义和使用价值。组织切片染色的质量好坏对于医学诊断,科研和教学至关重要。为了更好的研究神经组织,使医学诊断、科研和教学工作更为方便,本文对Toluidine Blue(甲苯胺蓝)染色方法做了一些改进。在传统的甲苯胺蓝染色过程中,仅考虑对细胞核和尼氏小体进行染色,未考虑细胞浆和其他细胞器:而改进后的甲苯胺蓝染色方法在甲苯股蓝染色后用伊红再染色,既考虑对细胞核和尼氏小体进行染色,也对细胞浆进行了染色。结果显示传统的Toluidine Blue染色结果光镜下观察,细胞核和尼氏小体都可见,即尼氏小体为深蓝色,细胞核为蓝色,染色背景为淡蓝色;改进后的染色结果光镜下观察,尼氏小体为紫蓝色,细胞核为蓝色,染色背景为粉红色。可见,改进后的染色方法染出的组织切片比传统的要清晰、美观。随着科学技术的飞速发展,病理学的研究也随之发展,病理技术势必进一步提高,来适应科技的进步和医学的发展。改进的尼氏小体染色法能够使脑组织切片更清楚观察,更有利于医学工作者对神经组织及尼氏小体的研究。     

中枢神经系统感染患者血清NSE和sICAM-1的改变

目的 :探讨中枢神经系统感染患者血清中NSE和sICAM 1水平的改变。方法 :采用ELISA法检测了 30例CNS感染的患者和 2 0例正常健康人血清中的NSE和sICAM 1水平。结果 :在CNS感染患者血清中NSE( 12 5 .6 8± 14 .38μg/L)和sICAM 1( 4 48.94± 96 .70μg/L)显著高于正常对照组的NSE( 6 .6 6± 1.2 5 μg/L)和sICAM 1( 2 91.78± 39.18μg/L) ,P <0 .0 1。在CNS感染各组中病毒性脑炎患者的NSE亦显著高于其他各组 ;sICAM 1在CNS感染各组间无显著性差异 ,P >0 .0 5。结论 :提示NSE和ICAM 1可作为CNS损害和感染的监测指标     

An immunohistochemical study of neuronal and glial cell reactions in retinae of rats with experimental glaucoma

Glaucoma is a common disease seen in the eye clinic, but its associated pathological processes, especially the role of glial cells in glaucomatous retinae, are still under debate. The aim of the present work was to study the responses of astrocytes, Müller cells and microglia in retinae of rats with experimental glaucoma. Glaucoma was induced in adult male Wistar rats by cauterizing limbal-derived veins and the changes in glial fibrillary acidic protein (GFAP), OX42, OX18, OX6 and EDI expression were studied by immunohistochemical staining. Neuronal cell viability was studied by immunostaining with the neuronal nuclei (NeuN) antibody. In the experimental glaucomatous eyes, a significant drop in the number of NeuN-positive neurons was observed from 7 days postoperation and beyond in both the ganglion cell layer and inner nuclear layer. The expression of GFAP and OX42 was increased during the first 2 months after operation and reduced in rats at 3 and 4 months. OX6 and OX18 immunoreactivity was induced in some microglia of both glaucomatous and sham-operated control eyes. Possible mechanisms of the reaction of astrocytes, Müller cells and microglia in neuronal degeneration following glaucoma are discussed.     

Inhibitory effect of ketamine on phosphorylation of the extracellular signal-regulated kinase1/2 following brain ischemia and reperfusion in rats with hyperglycemia

To determine if the inhibitory effects of ketamine on the extracellular signal-regulated kinase (ERK) 1/2 are involved in reduction of the hyperglycemia-exaggerated cerebral ischemic lesion, rats with normoglycemia, hyperglycemia, or hyperglycemia supplemented with ketamine were subjected to 15 min of forebrain ischemia, and then, reperfusion for 0.5, 1, and 3h. Phosphorylation of ERK1/2 in the brain tissues was assessed by immunohistochemistry and Western blot analysis. In rats with normoglycemia, we demonstrated a moderate increase of the ERK1/2 phosphorylation in the cingulum cortex and hippocampus CA3 following an ischemic intervention. It quickly dropped to control levels after reperfusion for 0.5h. In rats with hyperglycemia, however, the increase of the ERK1/2 phosphorylation in these areas was significantly higher in all animals reperfused. The neuronal death, detected by the TdT-mediated-dUTP nick end labeling assays, was found in the cingulum cortex (5.23+/-2.34, per high power feild) and hippocampus CA3 areas (6.29+/-3.68, per 1mm(2)) in hyperglycemic group after reperfusion for 3h. With ketamine treatment, the ERK1/2 phosphorylation in cingulum cortex and hippocampus CA1 and CA3 areas was found to be the same as that in normoglycemia rats. Our results suggest that hyperglycemia may increase the ischemic insult through modulation of the signal transduction pathways involving ERK1/2. The inhibitory effects of ketamine on the hyperglycemia-activated ERK1/2 phosphorylation are probably through inhibition of the N-methyl d-aspartate-mediated calcium influx, which subsequently reduce the hyperglycemia-exaggerated cerebral damage.     

Immunohistochemical study of neuron specific enolase and S-100 protein in Hirschsprung's disease

Summary The distribution of whole differentiated neurons in the intestines from 15 children with Hirschsprung's disease was investigated using neuron specific enolase (NSE) and the perineuronal elements were studied using S-100 protein immunostaining.In aganglionic segments, NSE immunoreactive ganglion cells and S-100 positive satellite cells were absent, but the hypertrophic nerve trunks did show a markedly positive NSE and S-100 immunoreactivity.Two different forms of aganglionic segment were present. One was the middle aganglionic segment of long segment aganglionosis which was almost completely dennervated. In the other type, there were several NSE positive nerve fibers in the muscularis propria of both the aganglionic segment of short segment aganglionosis and the distal aganglionic segment of long segment aganglionosis. These latter two aganglionic segments seemed to be innervated by extrinsic nerves.