Molecular modeling of mammalian cytochrome P450s

The cytochrome P450s are a superfamily of hemoprotein enzymes responsible for the metabolism of a wide variety of xenobiotic and endogenous compounds. The individual P450s exhibit unique substrate specificity and stereoselectivity profiles which reflect corresponding differences in primary sequence and tertiary structure. In the absence of an experimental structure, models for mammalian P450s have been generated by their homology with bacterial P450s of known structure. The rather low sequence identity between target and template proteins renders P450 modeling a challenging task. However, the substrate recognition properties of several P450s are consistent with recently developed working models. This review summarizes the major concepts and current approaches of molecular modeling of P450s. Received 28 September 1999; received after revision 25 November 1999; accepted 31 December 1999     

Genetic control of hippocampal cholinergic and dynorphinergic mechanisms regulating novelty-induced exploratory behavior in house mice

Summary Neurobehavioral genetics endeavors to trace the pathways from genetic and eenvironmental determinants to neuroanatomical and neurophysiological systems and, thence, to behavior. Exploiting genetic variation as a tool, the behavioral sequelae of manipulating these neuronal systems by drugs and antisera are analyzed. Apart from research in rats, this paper deals mainly with the genetically-influenced regulation in mice of exploratory behaviors that are adaptive in novel surroundings and are hippocampally-mediated. Special attention is paid to neuropeptidergic, GABAergic, and cholinergic synaptic functions in the mouse hippocampus.The behaviorally different inbred mouse strains C57BL/6 and DBA/2 show opposite reactions (reductions and increases, respectively, in exploration rates) to peripheral and intrahippocampal injections with agents that interfere with peptidergic, cholinergic, and GABAergic neurotransmission. These findings can be explained by an interdependent over-release of opioids, arrested GABA release, and excess acetylcholine in the hippocampal neuronal network of DBA/2 mice, as compared to C57BL/6 mice where these systems are functionally well balanced. Very similar results have been obtained with the lines SRH and SRL, derived from C57BL/6 and DBA/2, and genetically selected for rearing behavior. Most probably, the opioids act to disinhibit exploratory responses. An additional genetic approach is mentioned, in which four inbred mouse strains and one derived heterogeneous stock are used for estimating genetic correlations between structural properties of the hippocampal mossy fibers and levels of hippocampal dynorphin B, on the one hand, and frequencies of exploratory responses to environmental novelty, on the other.     

魔芋根腐病化学防治药剂筛选试验

为寻求经济、有效的防治魔芋根腐病的方法，本试验选7种杀菌剂对引起魔芋根腐病的病原菌（Alternar-ia）分别采用孢子萌发抑制法和菌饼法来进行室内毒力测定。结果表明，较为理想的化学防治药剂为绿亨二号、霜霸、达科宁，这3种药剂具有成本低廉，操作方便等优点，在生产上有很高的应用价值。     

微机电系统(MEMS)在施药中的应用

探讨微型生物传感器和药液贮囊容器单元植入体内,用一无线集成系统能控制药物的释放。接收传感器接收并反馈信号,可同时进行治疗药剂注射及组织采样等作业。本文主要介绍了MEMS(NEMS)技术在施药系统中的应用,并且对其发展给予了展望。     

作为抗癌药物载体的高分子研究进展

利用具有生物相容性的高分子作为载体，化学结合或物理包裹抗肿瘤化学药物．可提高抗肿瘤药物在体内的稳定性和生物利用度。本文从作为抗肿瘤药物载体的高分子的类型、制备方法、性能等方面综述了国内外的研究进展。     

高分子抗肿瘤导向药物的研究现状和发展

介绍了高分子抗肿瘤向药物的一些研究背景和研究状况，并对其发展历程进行了简单的描述。     

等温电荷理论及其检测固体介质中的陷阱分布

从一级陷阱化模型出发,推导出可用于检测固体介质中陷阱分布的等温电荷方程.基于固体介质在电场下注入载流子形成的空间电荷位置分布形式,提出用表面电位技术分开电子性和空穴性陷阱的实验方法,从而得到了单载流子陷阱信息.将理论与实验结合,测得了介质聚丙烯(PP)的陷阱分布.文中的理论结果和实验方法对于研究固体介质的陷阱信息具有一定意义.     

化学法制备铁磁流体的研究

叙述了以Fe、Fe_3O_4为基体材料、油酸等为活性剂,烃类化合物为载流体合成铁磁流体的实验结果.研究表明:在最佳条件下合成的铁磁流体,饱和磁化强度远高于单纯以Fe_3O_4为基体材料的传统磁流体,从而为研制高性能的新型磁流体提供了一种途径。     

安眠酮的吸附极谱波研究

在ｐＨ４．５缓冲溶液中，安眠酮在－１．１７Ｖ处产生一灵敏吸附极谱波，利用此波可测定微量安眠酮，线性范围为１．０×１０＾－７￣１．０×１０＾－６ｍｏｌ·Ｌ＾－１，检测下限为９．０×１０＾－８ｍｏｌ·Ｌ＾－１，所提出的方法用于片剂及血清中安眠酮的测定，结果满意。     

镇咳新药左羟丙哌嗪的合成

左羟丙哌嗪作为一种国内尚未进口和生产的药物，对其合成工艺的研究，可为工业生产该种药物打下基本的技术基础。该工艺用苯胺、二乙醇胺在酸性条件下，对220℃左右环合制得苯基哌嗪；环氧氯丙烷用10%的硫酸开环成3-氯-1，2-丙二醇；然后将这两种中间体在乙醇溶液中回流，制得消旋体羟哌丙嗪，再用酒后酸拆分制得左羟哌丙嗪。通过该方法可以制得产品，总收率达9.5%。并通过结构鉴定，确证其为左羟丙哌嗪。