摘要:

Early studies and reviews of the effects of carcinogens on bacteria and yeast are noted, after which a brief discussion deals specifically with chemical carcinogens and their relations with mutagenesis, deficiencies in DNA repair, RNA synthesis and function, and respiration‐deficient mutants. Specific chemical carcinogens are then reviewed as to their mode of action, mutagenic and carcinogenic potency, and biochemical effects, including induced biological alterations such as cytogenetic varients. Structure‐function relations are discussed for some types of compounds. The importance ofN‐hydroxylation of parent amines for mutagenicity and its effect on carcinogencity are related. Epoxide derivatives of polycyclic hydrocarbons can become covalently bound to nucleic acids. Nitrofurans have an excellent correlation with respect to their mutagenicity and carcinogenicity. Of theN‐oxides, 4‐nitroquinoline‐1‐oxide and its hydroxy derivative have been studied most extensively in a variety of bacterial systems regarding their mode of action. Acridine intercalation of DNA and covalent binding to nucleic acids of acetylaminofluorene after acetoxy derivative formation are reactions involved in the mutagenicity of bacteria and carcinogenicity in higher forms. β‐Propiolactone and nitrosamines acting as alkylating agents can cause frameshift mutations, as can aflatoxins, but only after metabolic conversion. Alkylating agents per se are mutagenic and carcinogenic without metabolic conversion. Ethionine, a carcinogenic agent, is nonmutagenic but can induce certain enzyme activities in yeast cells similar to those found in tumor cells. Several other kinds of chemical carcinogens are also reviewed.

ISSN:0098-4108    

DOI:10.1080/15287398109530005

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The toxicity and mutagenicity of 11 compounds individually and in mixtures were quantified in Salmonella typhimurium strains TA98, TA100, and TA1537 by a modification of the Ames spot test. The distance (millimeters) from the center of the petri dish to the bacterial growth front represented the toxic response. When mutagenicity occurred, the distance from the inner radius to the outer radius of the mutagenic growth represented the mutagenic response. Multiple regression analysis was used to quantify the toxicity and mutagenicity of individual compounds in the mixtures. The results indicate that the effects of compounds in mixtures are generally additive.

ISSN:0098-4108    

DOI:10.1080/15287398109530006

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Two hundred thirty Wistar rats, obtained from undisturbed mothers and from mothers that were exposed to temporary isolation and/or laparotomy, were randomly exposed to three of the following specific behavioral test procedures: (1) conditioned avoidance response, (2) water T‐maze, (3) open field, (4) activity wheel, (5) forelimb hanging, and (6) swimming. Performance of the offspring was examined during adulthood. Effects of previous testing on later testing performance and performance correlation between the two testing procedures were analyzed. The results indicate that (1) the maternal conditions manipulated in this study do not significantly affect behavior in the adult offspring (p> 0.05), and (2) performance of a previous task by the offspring does not significantly alter, and is not correlated with, the performance level on a second, unrelated task. Therefore, within these parameters, rats can be used for multiple testing procedures in a more practical and less costly means of behavioral investigation. These findings may be useful in the development and refinement of postnatal developmental toxicological screening procedures for agents that may be harmful to humans.

ISSN:0098-4108    

DOI:10.1080/15287398109530007

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The ability of ethanol to affect hindlimb ataxia and body weight changes induced by methyl mercury was studied in rats. Animals treated with either water or ethanol increased in body weight during the experiment and showed no impairment of hindlimb movement. Rats treated with methyl mercury also increased in body weight but developed moderate hindlimb ataxia. Animals treated with ethanol and methyl mercury initially gained but subsequently lost weight and exhibited severe hindlimb ataxia. The results provide evidence that ethanol can potentiate methyl mercury toxicity in rats and, by implication, in humans.

ISSN:0098-4108    

DOI:10.1080/15287398109530008

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Samples of airborne grain dust representing a variety of grains were examined for the presence of aflatoxins. Although aflatoxins could not be detected in most of the samples, one corn sample contained 130 ppb aflatoxin B1. When the components of this sample were separated according to aerodynamic diameter and analyzed for aflatoxins, it was found that particles with diameters 7–11 urn and <7 μm had much higher levels of aflatoxins than the sample as a whole. These findings suggest that measurements of aflatoxin in whole corn might underestimate aflatoxin levels in corn dust aerosols.

ISSN:0098-4108    

DOI:10.1080/15287398109530009

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

ISSN:0098-4108    

DOI:10.1080/15287398109529984

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor