EAAT expression by macrophages and microglia: still more questions than answers

Glutamate is the main excitatory amino acid, but its presence in the extracellular milieu has deleterious consequences. It may induce excitotoxicity and also compete with cystine for the use of the cystine–glutamate exchanger, blocking glutathione neosynthesis and inducing an oxidative stress-induced cell death. Both mechanisms are critical in the brain where up to 20% of total body oxygen consumption occurs. In normal conditions, the astrocytes ensure that extracellular concentration of glutamate is kept in the micromolar range, thanks to their coexpression of high-affinity glutamate transporters (EAATs) and glutamine synthetase (GS). Their protective function is nevertheless sensitive to situations such as oxidative stress or inflammatory processes. On the other hand, macrophages and microglia do not express EAATs and GS in physiological conditions and are the principal effector cells of brain inflammation. Since the late 1990s, a number of studies have now shown that both microglia and macrophages display inducible EAAT and GS expression, but the precise significance of this still remains poorly understood. Brain macrophages and microglia are sister cells but yet display differences. Both are highly sensitive to their microenvironment and can perform a variety of functions that may oppose each other. However, in the very particular environment of the healthy brain, they are maintained in a repressed state. The aim of this review is to present the current state of knowledge on brain macrophages and microglial cells activation, in order to help clarify their role in the regulation of glutamate under pathological conditions as well as its outcome.     

氨基酸分析中内标法与外标法的比较

<正> 氨基酸自动分析,现已成了许多实验室的常规工作。分析的准确性是特别地依赖于对标准物分析的精确性的。所以,对于如何才能获得高质量的标准因子,和标准化方法都应给予高度重视。     

NEW TAXA OF ILEX FROM THE PEOPLE''''S REPUBLIC OF CHINA

llex strigillosa T.R.DUDLEY,sp.nov. 〔Section Pseudoaquifolium S.-Y.HU(1950)Series Lougecaudatae S.-Y.HU(1950)〕. DIAGNOSIS: A I.kengii S.-Y.HU(1950)affinis sed ramulis et gemmis terminalis,dense cinerascentibus puberulento-strigillosis,stipulis tenuiter membranaceis minutis0.1mm longis vel minus fugacibus cito caducis,petiolis denso cinerascentibuspuberulento-strigillosis aliquado subglabris laminis versus,laminis foliorum mino-ribus 4—7.5cm longis 1—2cm latis basibus acutis ad attenuatis apicibussensim acuminatis vel caudato-acuminatis acuminibus brevioribus 5—10(—15)mm longis marginibus integris vel subintegris conspicue sinuolatis et apicibus     

基因在个体发育中的作用——从1885发展到1985的历史性概述

本文是Sander教授85年10月在上海细胞生物学研究所的学术报告的全文。从生机论和机械论讲起,在谈论了对种质学说的争论以及所产生的影响之后,Sander教授以昆虫为对象,概括地论述了在那以后如何设想基因在发育中起作用。报告不仅有系统性,并且包含着一些使人进一步思考的问题,值得向读者推荐。对此有兴趣的读者还可参考本刊创刊号(1979年)刊登的“遗传和发育的研究分久必合”一文。