用大肠杆菌CM89菌株对三种化学物抗突变作用的研究

本文以 E.coli CM891为靶细胞,用细菌内抗突变作用模式研究了肉桂醛,鞣酸,二烯丙三硫的抗4NQO 突变性及其作用机制。含质粒 pKM101的 CM891的高抗株(抗50μg/ml 氨苄青霉素)能提高该菌株的自发突变率和4NQO 诱发的突变率以及对鞣酸的杀伤抗性。肉桂醛的抗突变性不依赖质粒 pKM101效应,但与暂时性生长延搁有关。鞣酸及二烯丙三硫的抗突变机制可能包括质粒 pKM101介导的易误修复。上述三种化学物中每二种联合应用均显示抗4NQO 突变性的协同效应及对靶细胞的毒性杀伤作用。     

饮水有机浓集物致突变活性影响因素的研究

本文探讨饮水有机物浓集流速及加氯量对致突变活性的影响。试验表明，饮水有机物浓集流速控制在每分钟２倍树脂柱床体积时，可获得最佳致突变效果。当加氯量≥２０ｍｇ／Ｌ时，对ＴＡ９８±Ｓ９和ＴＡ１００—Ｓ９菌株有致突变活性，≤２ｍｇ／Ｌ时对ＴＡ９８±Ｓ９和ＴＡ１００±Ｓ９菌株无致突变活性。为最大限度减少致突变效应，在净水过程中保证流行病学安全前提下，减少加氯量和加氯次数是十分必要的。     

育龄妇女月经周期中心血管功能的变化

本研究采用先进的三维超声成像技术及多普勒技术对正常育龄妇女月经周期中心血管功能进行研究。结果：月经周期中ＨＲ、ＢＰ无变化；血清Ｅ２是周期性变化，排卵前达高峰。ＳＶ、ＣＯ、ＥＦ在排卵前期升高达峰值，显著高于月经期和黄体期；ＳＶＲ排卵前期最低，而Ｖｅｄ、Ｖｅｓ无变化。Ｖｍａｘ、Ａ、Ｅ在内源性Ｅ２高峰时明显加快，而Ｅ／Ａ比值无明显变化。结果提示：月经周期中随内源性Ｅ２的周期性变化，心脏功能也发生周期性变化。Ｅ２高峰时，心输出量、心搏量和射血分数达最高。外周阻力最低，心脏内血流速度加快。     

消化性溃疡的皮质醇分泌异常

采用放射免疫测定法研究了70例非应激性消化性溃疡患者的皮质醇分泌状态;并比较了患者与84例正常人的血清皮质醇浓度及其昼夜分泌节律。发现非应激性消化性溃疡血清皮质醇浓度明显高于健康对照组(P<0.01);然昼夜分泌节律相仿。结果提示,非应激性消化性溃疡有皮质醇分泌的明显异常。     

A simple method for screening assessment of acute toxicity of chemicals

We proposed a simple method for screening assessment of acute oral and dermal toxicity using only three rats and mice of each sex at each dose level. Animals were first treated with chemicals at a dose of 2000 mg/kg and were carefully observed for compound-related morbidity and mortality. If none of the animals died, the following toxicity tests were suspended. If some of the animals died, toxicity tests at doses of 200 and 20 mg/kg were performed. The approximate LD₅₀ values calculated by this method showed little difference between two separate laboratories and were in good agreement with LD₅₀ values reported in the literature. Our toxicological data also showed that LD₅₀ values were about 2–2.5 times the MNLD (maximum non lethal dose) in acute oral and dermal toxicity. This meant that a chemical could be regarded as having an LD₅₀ of about 4000 mg/kg or higher when there was no mortality at the dose of 2000 mg/kg. A chemical with such low toxicity would not require further testing for lethal effects. Therefore, this simple method combining the fixed-dose procedure with the limit test is suitable for determination of approximate LD₅₀ values of chemicals and for screening for necessity for classical full LD₅₀ test using many animals.This work was supported by a grant from Ministry of Health and Welfare in Japan (No. 467 and 511)     

Structure and promoter organization of the human monoamine oxidase A and B genes.

Monoamine oxidase (MAO) A and B play an important role in regulating levels of biogenic amines. MAO A and B cDNAs have been cloned and the deduced amino acids share 73% sequence identity. The genes for MAOA and B are comprised of 15 exons interspersed by 14 introns, span at least 60 kb and exhibit identical exon-intron organization. These findings suggest that the MAOA and MAOB genes are derived from the duplication of a common ancestral gene. The core promoter region of MAOA is comprised of two 90 bp repeats, each of which contains two Spl elements and lacks a TATA box. The MAOB core promoter region contains two sets of overlapping Spl sites which flank a CACCC element all upstream of a TATA box. The different organization of the MAOA and MAOB promoters may underlie their different cell and tissue specific expression.     

Nd：YAG激光对牙本质钙／磷比值的影响

为探讨Ｎｄ：ＹＡＧ激光对牙本质矿物含量的影响，应用扫描电镜和能谱仪定点测量５０个上前牙标本的根管壁（激光照射工和正常对比区）的钙、磷含量，结果表明，照射区牙本质钙／磷（Ｃａ／Ｐ）比值高于对比区，当激光能量达１５Ｗ以上时变化更为显著，提示Ｎｄ：ＹＡＧ激光能提高牙本质的钙化程度。     

胎盘型谷胱甘肽S转移酶mRNA在大鼠肝癌癌前病变组织中的原位表达

应用原位杂交技术，观察了二乙基亚硝胺（ＤＥＮ）诱发大鼠肝癌前病变组织中胎盘型谷胱甘肽Ｓ转移酶（ＧＳＴ－Ｐ）ｍＲＮＡ的表达。结果显示，ＧＳＴ－ＰｍＲＮＡ主要在癌前病变肝组织中的变异灶及灶外卵圆形细胞内表达，且在变异灶间或和同一灶内阳性细胞间表达程度不尽一致，而正常肝、再生肝组织中未见其表达。提示在分子水平上变异灶细胞及卵圆型细胞可能成为实验性肝癌的癌前期细胞     

测定血清及尿β2微球蛋白评估健康老年人肾功能的价值

测定72例健康老年人（60-84岁）和65例健康青中年人（20-50岁）血清和尿β2微球蛋白（β2m)，发现前血清β2m浓度比后明显增高（p<0.001)；老年组≥70岁尿液β2m浓度也明显增高（p<0.05)。结果表明肾小球滤过率下降随年龄增长而降低，以后再出现肾小管功能减退。本试验较血清尿素氮、肌酐和内生肌酐清除率测定更为敏感。