Studies of the dose-effect relation

Summary Dose-effect relations and, specifically, cell survival curves are surveyed with emphasis on the interplay of the random factors — biological variability, stochastic reaction of the cell, and the statistics of energy deposition —that co-determine their shape. The global parameters mean inactivation dose, , and coefficient of variance, V, represent this interplay better than conventional parameters. Mechanisms such as lesion interaction, misrepair, repair overload, or repair depletion have been invoked to explain sigmoid dose dependencies, but these notions are partly synonymous and are largely undistinguishable on the basis of observed dose dependencies. All dose dependencies reflect, to varying degree, the microdosimetric fluctuations of energy deposition, and these have certain implications, e.g. the linearity of the dose dependence at small doses, that apply regardless of unresolved molecular mechanisms of cellular radiation action.     

The use of primary cultures of adult rat hepatocytes to study induction of enzymes and DNA synthesis: Effect of nafenopin and electroporation

Summary Primary cultures of adult rat hepatocytes maintained in a well-differentiated state, in a chemically defined medium containing 2% DMSO, have been utilized to study the effect of non-mutagenic hepatocarcinogens such as the peroxisome proliferator nafenopin. The parameters chosen in this in vitro system were those that paralleled the major in vivo effects of nafenopin on the liver, mainly: the proliferation of the endoplasmic reticulum and induction of cytochrome P-452, the proliferation of the peroxisome compartment and the induction of cyanide-insensitive -oxidation of fatty acids and the stimulation of liver growth as measured by the DNA synthetic activity of the hepatocytes.In this review, we also describe the morphology of hepatocyte cultures prepared from previously electroporated hepatocytes and the potential for the use of electroporation to introduce growth related genes into hepatocyte cells to study the mechanisms of hepatocyte growth at the molecular level. In addition we describe the formation of endoplasmic reticulum whorls in these cultures as a consequence of nafenopin treatment. Whorl formation by hepatotrophic chemicals has been previously shown to occur in vivo; in this report, it is described for the first time in vitro.     

重组人促红细胞生成素对K562/A02多药耐药和K562药物敏感细胞增殖的影响

用ＭＴＴ法测定了重组人促红细胞生成素（ｒｈｕ－ＥＰＯ）对Ｋ５６２／Ａ０２多药耐药细胞系细胞和Ｋ５６２药物敏感细胞增殖的影响。研究发现,Ｋ５６２／Ａ０２与浓度为００７８、０１５６Ｕ／ｍＬ的促红素分别孵育时,其增殖活力比无ｒｈｕ－ＥＰＯ因子组低（Ｐ＜００１）;而Ｋ５６２与上述同样浓度的ｒｈｕ－ＥＰＯ孵育条件下,其增殖活力与无因子组比较差异无显著性意义（Ｐ＞０２０）。以上结果表明,ｒｈｕ－ＥＰＯ可能有抑制Ｋ５６２／Ａ０２细胞增殖的作用,而对Ｋ５６２细胞增殖无影响,提示ｒｈｕ－ＥＰＯ可能对多药耐药白血病的治疗有一些效果     

莲子贮存蛋白基因的表达与子叶叶肉细胞的变构

莲子贮存蛋白基因（ＳＰＧ）的表达受发育调控。子叶叶肉细胞变构早于ＳＰＧ的开始表达,随发育过程加剧。在贮存组织中细胞变构的发生有严格的时空顺序性。变构主要表现在细胞核体积增大,外形变不规则,染色质分布不均匀化,核膜局部消失。     

小檗胺及其衍生物的结构对宫颈癌（HeLa）细胞生长增殖的影响

本文研究了不同结构的新型钙调查蛋白（ＣａＭ）拮抗剂－－小檗胺（Ｂ０）及三种衍生物ＥＢＢ、Ｂ４、Ｂ２）对宫颈癌细胞的生长曲线、单细胞克隆、＾３Ｈ－ＴｄＲ掺入、线粒全脱氢酶活性的影响，并测定了小檗胺类化合物作用ＨｅＬａ细胞后，细胞内ＣａＭ 变化，结果发现，四种小檗胺类化合物对ＨｅＬａ细胞的生长和增殖有明显的抑制作用；其抑制增殖的ＩＣ５０值分别为Ｂ０１２．５μｍｏｌ／Ｌ、Ｂ２２．０μｍｏｌ／Ｌ、Ｂ４２．     

MTT比色分析法在贴壁生长细胞药物敏感性测定中的应用

用ＭＴＴ法测定了几种小檗胺类化合物对三种贴壁生长细胞生长增殖的影响。结果显示：ＭＴＴ分析法比传统的活细胞计数法，单细胞克隆尖及＾３Ｈ－ＴｄＲ掺入法测定样品，省时，省试剂，精确度高，重复性好及没有同位素污染等优点，是肿瘤药物研究中较理想的检测方法。     

细胞工程在鱼类育种中的应用

介绍了鱼类细胞工程育种的研究现状和成果。其主要技术包括核移植、细胞融合、雌核发育、雄核发育和多倍体诱导，其中雌核发育和多倍体诱导是潜力较大的育种方法，并在生产中得到了应用。     

烟草叶肉原生质体再生壁形成的电镜研究

电镜观察表明,新分离的烟草叶肉原生质体表面光滑,在质膜外没有纤维状物质,内质网和高尔基体几乎没有发育:培养1天后,线粒体明显增加,粗面内质网和高尔基体沿质膜发育,质膜变得粗糙;2天后,质膜发生折皱,高尔基囊泡向质膜外分泌它的内含物;6天后,质膜表面出现明显松散分布的再生壁。在培养基中附加200 ppm 香豆素处理,在培养1天后,质膜仍然光滑,未出现内质网和高尔基体;2天后,质膜开始变粗糙,内质网开始发育。试验表明,质膜、内质网、高尔基体在原生质体再生壁形成中起重要作用,并讨论了它们的可能作用。香豆索可能是在一定时同内,通过抑制质膜的活动和内质网、高尔基体的发育而抑制壁的再生。     

多孔玻碳切片光谱电化学电解池研制

本文采用多孔玻碳切片作为电极材料,制作成功玻碳光透电极,并以K_4Fe(CN)_6K_3Fe(CN)_4作为氧化还原体系,测定了式量电位E°′与转移电子数n。