摘要:

AbstractThe hepatocyte primary culture (HPC)/DNA repair assay using rat hepatocytes was developed to identify genotoxic chemicals. Since there are species differences in susceptibility to chemical carcinogens, it was desirable to extend the assay to other species. Carcinogens and noncarcinogens from six structural classes were tested with hepatocytes from B6C3F1mice or Syrian hamsters. In hepatocytes from both species, DNA repair was elicited by the carcinogens methyl methanesulfonate, aflatoxin B1, 2‐acetylaminofluorene, benzo(a)pyrene, dimethylnitrosamine, nitrosopyrrolidine, 3'‐methyl‐4‐dimethylaminoazobenzene, and p‐dimethylaminoazobenzene. With aflatoxin B1, mouse hepatocytes required a dose of 10−4M for a maximum response while only 10‐6 was needed for hamster hepatocytes. All the presumed noncarcinogens, except 4‐dimethylaminoazoben‐zene‐4'‐sulfonyl chloride, were negative in mouse hepatocytes. This chemical, as well as aflatoxin G2and pyrene, which have not been tested for carcinogenicity in the hamster, were positive in hamster hepatocytes. These findings demonstrate that genotoxic chemicals can be identified by the HPC/DNA repair assay using hamster or mouse hepatocytes. Furthermore, in vivo differences in susceptibility to chemical carcinogens such as aflatoxin B are reflected

ISSN:0192-2521    

DOI:10.1002/em.2860050102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractStreptomycin‐dependent (SMd) mutant strains of Salmonella typhimurium TA98 and TA 100 were isolated. A highly sensitive detection system was obtained by using these SMd derivatives for the SMd — SMind mutation. The system was available for testing the mutagenicities of samples containing histidine, such as f

ISSN:0192-2521    

DOI:10.1002/em.2860050103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThe direct‐acting mutagenicity of 5‐nitroacenaphthene for Salmonella typhimurium is dependent upon the reduction of the nitro function as evidenced by the significant decrease in mutagenicity seen with nitroreductase‐deficient Salmonella strains. Addition of microsomal preparations results in a significant increase in mutagenicity and a by‐passing of the block in nitroreductase‐deficient and arylhy‐droxylamine esterifying‐deficient enzyme strains. The results are taken to indicate that the microsome‐induced mutagenicity is due primarily to oxidation of the acenaphthene moiety. The results are consistent with recent studies which indicate that the nitro function exercises a directing effect on

ISSN:0192-2521    

DOI:10.1002/em.2860050104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThe composition of the effluents from incineration plants has been studied by several authors, and some chemical compounds have been identified as hazardous to the health of the people living in the environs of such plants. On the other hand, very little is known about the chemical risks for the people working inside the incineration plants. In the present paper, an evaluation of these risks has been attempted by testing for the mutagenic activity of the extracts of airborne particulates collected inside the working area of the Municipal Incinerator of Trieste. Most samples of dust were proved to be mutagenic by the Ames test, indicating that the environment is heavily polluted with incompletely burnt materials. In fact, when a sample of settled dust was heated at high temperatures, its mutagenic activity disappeared. In addition, samples of solid residues collected at the end of the combustion process showed only weak, if any, mutagenic response.

ISSN:0192-2521    

DOI:10.1002/em.2860050105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractWe determined optimal conditions to quantitatively select ouabain‐resistant (Ouar) mutants induced by chemical carcinogens in a rat prostate epithelial cell line (RPYK). These conditions included selection of Ouar mutants in 3 mM ouabain, an expression time of two days following a two‐day treatment with carcinogens, and a reseeding density of 2 × 105 mutagenized cells per 100 mm dish to select mutants in ouabain. Ouarmutants induced by N‐methyl‐N'‐nitro‐N'‐nitrosoguanidine (MNNG) remained stably Ouarwhen passaged in nonselective medium. Hemicyst formation, a characteristic of epithelial cells, was reversibly inhibited by ouabain in wild‐type cells and was resistant to ouabain in Ouarcells. The direct‐acting carcinogens MNNG and methylazoxymethanol‐acetate (MAMA) and the environmentally widespread procarcinogens aflatoxin B1and benzo(a)pyrene increased the frequency of Ouar mutants in RPYK cells. The procedures developed here now make it possible to detect some environmental carcinogens likely to cause prostate cancer by virtue of their ability to mutate cultured prostate epithelial RPYK cells. The sensitivity of the RPYK cell line to aflatoxin‐induced cytotoxicity and mutagenesis also makes it a useful cell system in which to study enzymes governing the conversion of aflatoxin to

ISSN:0192-2521    

DOI:10.1002/em.2860050106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractFormaldehyde is a large production volume chemical widely distributed in research laboratories, industrial workplaces, and home and personal environments. Inhalation studies with formaldehyde have documented its ability to produce squamous cell carcinomas in rats. When primary hamster embryo cells were treated by gaseous exposure to formaldehyde or by incorporation into the medium, a dose‐related increase in the frequency of SA7 virus transformation was produced. The length of chemical treatment and the time interval before subsequent addition of transforming virus was critical, with two‐hr treatment times as the most efficient. Treatment by gaseous exposure permitted utilization of lower treatment concentrations. Determination of formaldehyde concentrations in culture media of bioassay dishes treated by this method documented that 2.2 fig/ml produced significantly enhanced viral transformation. Exposure of hamster embryo cells to formaldehyde by these methods produces reproducible and quantitative genotoxic effe

ISSN:0192-2521    

DOI:10.1002/em.2860050107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThe effects of caffeine, acriflavine, spermine, quinacrine, and adenosine on spontaneous and UV‐induced prophage induction in repair‐proficient and ‐deficient strains of lysogenic Escherichia coli were examined. Caffeine caused a coinducing effect on UV induction in KMBL 160 (repair proficient) and KMBL 163 (uvrA), an anti‐inducing effect in KMBL 161 (uvrE), and had no detectable effect in KMBL 164 (uvrC). Acriflavine increased UV induction in KMBL 160 and decreased it in all three repair‐deficient mutant strains. Spontaneous induction was reduced by acriflavine in all four strains. Spermine caused a decrease in UV induction in KMBL 160 and KMBL 164, while it had limited effect in KMBL 161 and KMBL 163. For spontaneous induction spermine caused an increase in KMBL 160 and KMBL 163, a decrease in KMBL 164 and no detectable effect in KMBL 161. Quinacrine had no significant effect on spontaneous induction in KMBL 160 and KMBL 164, but caused a decrease in spontaneous induction in KMBL 161 and KMBL 163. Quinacrine produced no effect on UV induction in KMBL 160; however, it decreased UV induction in the three repair‐deficient strains to some extent. A significant increase in spontaneous induction in KMBL 160 was caused by adenosine, while it had little effect in the repair‐deficient strains. UV induction was not affected

ISSN:0192-2521    

DOI:10.1002/em.2860050108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractIn order to evaluate the cytogenetic findings previously obtained on induced abortions in women exposed to 2,3,7,8 tetrachlorodibenzo‐p‐Dioxim (TCDD) after the Seveso accident, chromosome analyses were carried out on a comparable control sample. The frequencies of aberrant cells, the relative proportions of individual types of chromosome aberration, the average number of lesions per damaged cell, and the frequencies of polyploids do not differ significantly in maternal blood and placenta in the two samples. A highly significant increase in the frequencies of aberrant cells and in the average number of aberrations per damaged cell was found in the fetal tissues in the group of exposed pregnancies. A noticeable feature of the data on the frequencies of cells with aberrations is the marked variability among individuals within tissues and within samples. On the basis of these results, the authors point to the need to continue cytogenetic investigations on interrupted pregnancies in TCDD‐exposed and nonexposed

ISSN:0192-2521    

DOI:10.1002/em.2860050109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractMutagenic activity in particulate airborne pollutants in several samples collected in a wide variety of industrial, residential, and small‐scale factory districts over the past seven years was detected by the Ames test. The particulate air samples that were not contaminated with several chemicals such as NO (<0.001 ppm), NO2(<0.001 ppm), and SO2 (<0.001 ppm) showed only low mutagenic activity (1 revenant /m ) when they were tested with Salmonella typhimurium strain TA98 in the presence of S9 mix. However, most of the samples polluted by particulate matters showed high mutagenicity, with responses varying from 2.4 to 445 revertants per m3: 67 samples from an industrial area induced an average of 44 revertants per m3; 60 from a residential area, 16.2; and 10 from a small‐scale factory area, 72.1. For assessing the mutagenic potential of the pollution in the atmosphere, the frequency of mutation determined with strain TA98 in the presence of S9 mix was used to divide the samples tentatively into five groups (A‐E) on the basis of the normal logarithmic distribution curve of 137 samples. Air samples belonging to group A gave less than 2.3 revenants per m3of air (1.12 ± 0.12, no pollution); those of group B gave a range of 2.4 to 8.6 (5.93 ± 1.91, slight pollution); those of group C gave a range of 8.7 to 30.2 (16.0 ± 5.36, moderate pollution); those of group D gave a range of 30.3 to 115 (56.7 ± 20.1, considerable pollution); and those of group E gave more than 116 (234 ± 119, heavy pollution). Of the 137 samples tested, 6 samples (4.4%) were assigned to group A, 38 (27.7%) to group B, 52 (38.0%) to group C, 34 (24.8%) to group D, and 7 (5.1%) to group E. Furthermore, the samples in an industrial area were classified in the order of group C (35.8%), group B (26.9%), group D (22.4%), group E (8.96%), and group A (5.97%), and those in a residential area in the order of group C (46.7%), group B (33.3%), group D (18.3%), and group

ISSN:0192-2521    

DOI:10.1002/em.2860050110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractTo determine structural features necessary for the production of direct mutagenic activity from oligoamine‐nitrate reaction mixtures, we systematically tested a group of aliphatic amine substrates for comutagenic action with nitrite. The ability to react with nitrite and form direct‐acting mutagenic derivatives was common to a reasonably well defined class of aliphatic polyamines. In general, primary‐secondary diamino compounds were mutagenic in the Ames Salmonella tester system when reacted with nitrite, whereas primary and secondary amines produced no direct mutagenic activity when tested separately. In combination with teritary amino groups, primary amines were inactive; one secondary‐tertiary amine was tested, and this substrate produced mutagenic a

ISSN:0192-2521    

DOI:10.1002/em.2860050111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY