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1.
应用模糊极小极大神经网络研究了化合物复杂结构和性能(QSAR)之间的关系,用该法进行几组化合物致癌的识别,结果优于线性回归的方法,对此作出一些分析。  相似文献   
2.
Valepotriates are epoxide-bearing triesters of the monoterpene alcohol 4,7-dimethylcyclopenta-(c)-pyrane isolated from the roots of several Valerianacae species. They are regarded as the main tranquilizing constituents of these drugs.Although the valepotriates valtrate/isovaltrate (VAL) and dihydrovaltrate (DH-VAL) showed a strong alkylating activity against the nucleophilic agent 4-(p-nitrobenzyl)-pyridine (NBP), they were not clearly mutagenic for the strains TA98, TA100, TA1535, and TA1537 of Salmonella typhimurium or for the strains WP2 and WP2 uvrA of Escherichia coli in the absence of a metabolic activation system (S9-mix). However, the valepotriates were mutagenic for TA100, WP2 and WP2 uvrA at concentrations up to about 1.0 mole/plate when S9-mix was added to the test system. With more than 1 mole/plate the valepotriates were toxic in the presence of a metabolic activation system for all strains tested. The mutagenicity of the valepotriates was inversely related to the protein content of the S9-mix used. The mutagenicity and toxicity of the valepotriates could be inhibited when the S9-mix was preincubated with the esterase inhibitor paraoxon (1 mM) for 5 min before the test compounds and bacteria were added. Therefore, bioactivation of the valepotriates by an enzymatic hydrolysis of their ester groups is considered. This could be proven by activating the valepotriates with purified esterase.Parts of this paper were presented at the Congress, Fortschritte in der Arzneimittelforschung, April 17–20, 1983 in Munich  相似文献   
3.
The genetic activity of several medical grades of the anthelmintic drug pyrvinium pamoate, which is a dipyrvinium salt, was studied in a diploid mitotic recombination and gene conversion assay (strain D5 ofSaccharomyces cerevisiae), and in several haploid yeast reversion assays (strains XV185-14C, XY718-1A, and 7854-1A). All of the samples were recombinogenic in strain D5 and mutagenic in the haploid strains, however, the degree of genetic activity varied considerably among the medical grades of pyrvinium pamoate that were tested. Similarly, these samples varied in degree of mutagenicity when they were tested in strains TA97, TA98, TA100, and TA102 ofSalmonella typhimurium, but some of the medical grades of pyrvinium pamoate were mutagenic both in the presence and in the absence of the metabolic transformation system, whereas other medical grades of the drug required such activation to be mutagenic. In addition, the medical grades and dosage forms of several brands of pyrvinium pamoate were examined for purity by fluorescence high pressure liquid chromatography (HPLC) using a methanol:water (9010) solvent system. The HPLC data indicate that monopyrvinium salts are the major contaminants in these pharmaceuticals. In general, there is a correlation between the degree of genetic activity and toxicity, and the number and relative quantity of impurities found in each sample.  相似文献   
4.
二噁英是目前人们十分关注的一种毒性很强的环境污染物。本文介绍了二噁英的理化特性、污染来源、暴露吸收途径、毒性、致突变性、致癌性和致畸性以及控制措施等。  相似文献   
5.
含氯含碘及戊二醛类高效消毒剂毒性探讨   总被引:1,自引:0,他引:1  
目的探讨高效消毒剂的毒性作用。方法选择某品牌的三种消毒剂,参照《消毒技术规范》中的试验方法进行了实验。结果①某品牌消毒片(含氯)小鼠经口LD50为2228mg/kg,属低毒类,戊二醛和复合碘为实际无毒类;②消毒片和戊二醛一次皮肤刺激、复合碘一次眼刺激和多次皮肤刺激试验均无明显刺激性;③三种消毒剂小鼠骨髓细胞微核试验均为阴性,致突变性检测结果为非染色体断裂剂。结论三种消毒剂急性毒性和对皮肤粘膜的刺激作用是可以接受的  相似文献   
6.
Microsomal monooxygenases catalyze the biosynthesis of epoxides from olefinic and aromatic compounds whilst microsomal epoxide hydratase and cytoplasmic glutathione S-transferases are responsible for their further biotransformation. Although catalytically very efficient the cytoplasmic glutathione S-transferases play, due to their subcellular localization, a minor role in the inactivation of epoxides derived from large lipophilic compounds and were, therefore, not included in this study. It was shown with such a lipophilic compound, benzo(a)pyrene, as a model substance and with liver enzyme mediated bacterial mutagenesis as biological endpoint that species and strain differences in epoxide hydratase and monooxygenases are reflected in very dramatic differences in mutagenicity of benzo(a)pyrene which varied from extremely potent to a degree which could easily be overlooked. In order to investigate whether the differences in enzyme activities were causally linked to the observed differences in mutagenicity, the enzyme activities were modulated by inhibition and induction. These manipulations were always accompanied by the corresponding changes in mutagenicity.It is concluded that species such as mice which possess high monooxygenase activity but very low epoxide hydratase activity are much more susceptible than man to those toxic effects which are mediated by metabolically formed epoxides which are substrates of epoxide hydratase. In this regard, it is especially noteworthy that mice possess a much lower hepatic epoxide hydratase activity than man.Presented at the Symposium Influence of Metabolic Activations and Inactivations on Toxic Effects held at the 18th Spring Meeting of the Deutsche Pharmakologische Gesellschaft, Section Toxicology, D-6500 Mainz, March 15, 1977  相似文献   
7.
核桃提取物急性毒性和遗传毒性的实验研究   总被引:2,自引:0,他引:2  
目的 观察核桃提取物对动物的毒性安全性并对其进行评价。方法 通过大鼠急性毒性实验 ,大鼠亚急性毒性实验 ,Am es试验以及小鼠睾丸染色体畸变试验 ,小鼠骨髓微核试验和小鼠单细胞凝胶电泳试验对其毒性安全性进行实验和评价。结果 急性毒性实验中 ,核桃提取物经口半数致死量 ( L D50 ) >10 g/ kg体重 ;亚急性毒性试验结果显示 :各项生化指标均在正常范围之内 ,而且各组之间差异无显著性 ,各组脏体比及体重增长差异无显著性 ;Am es试验结果显示 :自发回变组与各剂量组之间差异无显著性 ,而与阳性对照组差异有显著性 ;小鼠骨髓微核试验显示 :阴性对照组与各剂量组之间差异无显著性 ,阳性对照组与阴性对照组及各剂量组之间差异有显著性 ;小鼠睾丸染色体试验与单细胞凝胶电泳试验结果和微核试验相一致。结论 核桃提取物在急性毒性试验、亚急性毒性试验及遗传毒性试验中均未显示有毒性作用 ,符合《食品安全性毒理学评价程序和方法》GB15 193 .1- 94的要求 ,初步认为用于人体是安全的  相似文献   
8.
Saffron is harvested from the dried, dark red stigmas of Crocus sativus L. flowers. It is used as a spice for flavoring and coloring food and as a perfume. It is often used for treating several diseases. We assessed the antimutagenic, comutagenic and cytotoxic effects of saffron and its main ingredients using the Ames/Salmonella test system, two well known mutagens (BP, 2AA), the in vitro colony formation assay and four different cultured human normal (CCD-18Lu) and malignant (HeLa, A-204 and HepG2) cells. When only using the TA98 strain in the Ames/Salmonella test system, saffron showed non-mutagenic, as well as non-antimutagenic activity against BP-induced mutagenicity, and demonstrated a dose-dependent co-mutagenic effect on 2-AA-induced mutagenicity. The saffron component responsible for this unusual comutagenic effect was safranal. In the in vitro colony formation test system, saffron displayed a dose-dependent inhibitory effect only against human malignant cells. All isolated carotenoid ingredients of saffron demonstrated cytotoxic activity against in vitro tumor cells. Saffron crocin derivatives possessed a stronger inhibitory effect on tumor cell colony formation. Overall, these results suggest that saffron itself, as well as its carotenoid components might be used as potential cancer chemopreventive agents.  相似文献   
9.
一种新来源天然冰片与合成冰片的致突变性比较研究   总被引:4,自引:0,他引:4  
目的与方法采用鼠伤寒沙门氏菌回复突变试验(Ames试验),比较天然冰片与合成冰片的致突变作用.结果在标准平板掺入法试验中,天然冰片与合成冰片在0.4~250.0μg/皿范围内,无论有或无S9活化系统,对鼠伤寒沙门氏菌突变株(TA97、TA98、TA100、TA102)的回变菌落数均无明显影响,且回变菌落背景正常.结论新来源天然冰片与合成冰片在该实验室条件下均不具致突变效应.  相似文献   
10.
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