Alzheimer’s disease: the impact of age-related changes in reproductive hormones

The relationship between hormones and Alzheimers disease (AD) has been intensely researched. While the majority of this work has focused on the sex steroids, estrogens, and more recently androgens, a serendipitous patient encounter led one of us (R.L.B.) to question whether other hormones of the hypothalamic-pituitary-gonadal axis might play a role in the pathogenesis of AD. The age-related decline in reproductive function results in a dramatic decrease in serum estrogen and testosterone concentrations and an equally dramatic compensatory increase in serum gonadotropin concentrations. Indeed, there is growing evidence that the gonadotropin luteinizing hormone, which regulates serum estrogen and testosterone concentrations, is an important causative factor in the development of AD. This review provides information supporting the gonadotropin hypothesis. We put forth a novel mechanism of how changes in serum luteinizing hormone concentrations could contribute to the pathogenesis of AD and discusses potential therapeutic anti-gonadotropin compounds.     

NO.7信令网集中监测系统维护管理及发展趋势分析

NO .7信令网被称为电信网的神经 ,由于我国电信网的特殊情况 ,需要综合的网络管理系统与监测系统来实现NO .7信令网与本地电话网的智能管理和超前维护 ,本文深入分析了NO .7信令网集中监测系统的体系结构和技术特点 ,提出了监控系统的发展趋势。     

Cellulase genes from the parabasalian symbiont <Emphasis Type="Italic">Pseudotrichonympha grassii</Emphasis> in the hindgut of the wood-feeding termite <Emphasis Type="Italic">Coptotermes formosanus</Emphasis>

Cellulase genes of Pseudotrichonympha grassii (Hypermastigida: Eucomonymphidae), the symbiotic flagellate in the hindgut of the wood-feeding termite Coptotermes formosanus, were isolated and characterized. The nucleotide sequences of the major cellulase component in the hindgut of C. formosanus were determined based on its N-terminal amino acid sequence. The five isolated nucleotide sequences (PgCBH-homos) had an open reading frame of 1350 bp showing similarity to catalytic domains of glycoside hydrolase family (GHF) 7 members, and primary structure comparison with GHF7 members whose tertiary structures are well-characterized revealed the overall similarity between PgCBH-homo and the catalytic domain of a processive cellulase Cel7A (formerly CBHI) from the aerobic fungus Trichoderma reesei. Functional expression of PgCBH-homos in Escherichia coli, using the carboxymethylcellulose-Congo red assay, demonstrated the actual cellulolytic activity of PgCBH-homo. RT-PCR showed that PgCBH-homos were expressed, from the three flagellates in the hindgut, specifically in P. grassii. Received 10 July 2002; accepted 26 July 2002 RID="*" ID="*"Corresponding author.     

铋与7—碘—8—羟基喹啉—5—磺酸络合吸附波及其应用

建立了铋(Ⅲ)-7-碘-8-羟基喹啉-5-磺酸体系在单扫示波极谱仪上测定微量铋的方法。以0.25mol/L NaOH为支持电解质,该体系有一灵敏的导数极谱波,峰电位为-0.58v(vs.SCE)。峰电流与铋的浓度在0.050～1.1μmol/L范围内成正比。应用循环伏安、脉冲极谱等方法确证该极谱波属于络合吸附波。测得该吸附型体的络合比为Bi(Ⅲ):IQSH=1∶1。     

用NJTU模型描述CCITT七号信令系统

本文吸取了UCLA图模型,Unified模型,数值Petri网模型(NPN)的优点,提出一种新的描述通信协议的混合模型(NJTU模型)。 NJTU模型易于描述具有多个并行工作的子系统的通信协议,能充分反映子系统内部的控制转移和各模块间的相互关系。本文第二节给出了NJTU模型的定义,第三节阐明了NJTU模型的特点,并同其它几种模型进行比较,第四节给出了NJTU模型的应用例子。     

Human and rodent type 1 11β-hydroxysteroid dehydrogenases are 7β-hydroxycholesterol dehydrogenases involved in oxysterol metabolism

Interconversion between cortisone and the glucocorticoid receptor ligand cortisol is carried out by 11-hydroxysteroid dehydrogenase (11-HSD)isozymes and constitutes a medically important example of pre-receptor control of steroid hormones. The enzyme 11-HSD type 1 (11-HSD1) catalyzes the conversion of cortisone to its active receptor-binding derivative cortisol, whereas 11-HSD type 2 performs the reverse reaction. Specific inhibitors against the type 1 enzyme lower intracellular levels of glucocorticoid hormone, with an important clinical application in insulin resistance and other metabolic disorders. We report here on the in vitro oxysterol-metabolizing properties of human and rodent 11-HSD1. The enzyme, either as full-length, membrane-attached, or as a transmembrane domain-deleted, soluble form, mediates exclusively conversion between 7-ketocholesterol and 7-hydroxycholesterol with similar k_cat values as observed with glucocorticoid hormones. Thus, human, rat, and mouse 11-HSD1 have dual enzyme activities like the recently described 7-hydroxysteroid dehydrogenase/11-hydroxysteroid dehydrogenase from hamster liver, but differ fundamentally from the latter in that 7-OH rather than 7-OH dehydrogenase constitutes the second activity. These results demonstrate an enzymatic origin of species differences in 7-oxysterol metabolism, establish the origin of endogenous 7-OH cholesterol in humans, and point to a possible involvement of 11-HSD1 in atherosclerosis.Received 30 December 2003; received after revision 16 February 2004; accepted 16 February 2004     

含氟香豆素型激光染料的研究

合成了七个含氟香豆素型激光染料,测定了它们的光谱数据、激光性能、调谐范围和激光转换效率。其中两个染料具有较宽的调谐曲线:467～522 nm和471～491 nm;较高的能量转换效率:37%和22.9%;以及稳定的光化学性能。具有实用价值。     

柏木基甲醚的合成研究

柏木基甲醚是以天然柏木醇为原料,经甲基烷基化制得。甲基化方法很多,本文采用新的甲基化方法,使产品的质量、产量达到了满意的效果。     

在现有电话网中发展智能业务的研究

介绍了智能网结构及其通信协议，分析了在现有电话网中可用来迅速开放智能业务的两种智能平台和叠加式智能网的结构及性能，探讨了在省内电话网中建设初级智能网络的方法及策略