Alexander disease: putative mechanisms of an astrocytic encephalopathy

Alexander disease (AXD) is the first primary astrocytic disorder. This encephalopathy is caused by dominant mutations in the glial fibrillary acidic protein (GFAP) gene, encoding the main intermediate filament of astrocyte. Pathologically, this neurodegenerative disease is characterised by dystrophic astrocytes containing intermediate filament aggregates associated with myelin abnormalities.More than 20 GFAP mutations have been reported. Many of them cluster in highly conserved regions between several intermediate filaments. Contrary to other intermediate filament-related diseases, AXD seems to be the consequence of a toxic gain of function induced by aggregates. This is supported by the phenotype of mice overexpressing human GFAP. Nevertheless, GFAP null mice display myelin abnormalities and blood-brain barrier dysfunction that are present in AXD.Given the pivotal role of astrocytes in brain physiology, there are many possibilities for astrocytes to dysfunction and to impair the functions of other cells. Physiopathological hypotheses are discussed in the frame of AXD.Received 11 April 2003; received after revision 22 July 2003; accepted 31 July 2003Both authors contributed equally to this work.     

星形胶质细胞在学习记忆中的作用

星形胶质细胞是神经胶质细胞的主要组成部分,遍布整个神经系统.以往认为星形胶质细胞的功能主要为支持营养神经元,参与物质代谢,血脑屏障形成等等,但最近研究发现它们还可促进突触形成,影响信号传导及突触可塑性,从而在学习记忆的形成中发挥重要作用.     

小鼠脊髓损伤后对少突胶质细胞前体细胞发育的影响

为研究小鼠脊髓损伤后脊髓少突胶质细胞前体细胞的发育分化情况,选择基因型为PDGFRa-creER+/Rosa-tdTomato+小鼠为研究对象,用脊髓损伤仪损伤小鼠脊髓T8或T9段.伤后休养30d取材,通过免疫荧光、激光共聚焦和电镜的方法分析取样材料,发现在物理损伤30d后,大部分表达tomato阳性的细胞同时表达少突胶质细胞的标志蛋白CC1,一小部分细胞同时表达星形胶质细胞的标志蛋白GFAP.     

Effect of olfactory ensheathing cells on reactive astrocytes <Emphasis Type="Italic">in vitro</Emphasis>

Olfactory ensheathing cells have been used in several studies to promote repair in the injured spinal cord. However, cellular interaction between olfactory ensheathing cells and glial cells induced to be reactive in the aftermath of injury site has not been investigated. Using an in vitro model of astrogliosis, we show that reactive astrocytes expressed significantly less glial fibrillary acidic protein (GFAP) when cultured both in direct contact with olfactory ensheathing cells and when the two cell types were separated by a porous membrane. Immunofluorescence staining also suggested that reactive astrocytes showed decreased chondroitin sulfate proteoglycans in the presence of olfactory ensheathing cells, although the reduction was not statistically significant. No down-regulation of GFAP was observed when reactive astrocytes were similarly cultured with Schwann cells. Cell viability assay and bromodeoxyuridine uptake showed that proliferation of reactive astrocytes was significantly increased in the presence of olfactory ensheathing cells and Schwann cells. Received 27 February 2007; received after revision 30 March 2007; accepted 3 April 2007     

脊髓中S100b基因的表达模式研究

S100b是一种钙离子结合蛋白,与阿尔兹海默症、帕金森症、神经痛等多种神经系统疾病有关.实验通过原位杂交和免疫荧光技术对S100b在中枢神经系统的表达模式进行直接分析,发现S100b主要表达在脊髓灰质星形胶质细胞和脊髓白质中正在成熟的少突胶质细胞中,表明其并不能很好的作为星形胶质细胞的分子标记物.     

MR增强检查对幕上星形胶质细胞瘤分级的价值

：探讨磁共振增强检查对幕上星形胶质细胞瘤分级的价值及术后肿瘤复发的征象。方法：选择有完整资料并经手术病理证实的２７例进行回顾性研究,观察其ＭＲ平扫及增强表现,并与病理进行对照。结果：平扫均显示病变为长Ｔ１长Ｔ２异常信号,但信号强度不均、边界不清、病灶附近水肿较多,次为病灶内坏死液化。增强扫描中,２０例有增强表现,２例术后肿瘤复发者可见环状或环壁节状增强。ＭＲＩ分级与病理分级对比：病理诊为Ⅰ～Ⅱ级８例,ＭＲＩ诊Ⅰ级２例,Ⅱ级８例;病理诊Ⅱ级１０例,ＭＲＩ诊Ⅰ级２例,Ⅱ级８例;病理诊Ⅱ～Ⅲ级４例,ＭＲ诊Ⅱ级３例,Ⅲ级１例;病理诊Ⅳ级１例,ＭＲ诊Ⅲ～Ⅳ级。结论：ＭＲ增强检查对幕上星形胶质细胞瘤的分级是有价值的