摘要:

AbstractNitro‐polynuclear aromatic hydrocarbons are found in diesel particulates. These compounds are potent mutagens in the Ames test. To determine whether nitro‐polynuclear aromatic hydrocarbons are active in a mammalian cell assay, 1‐nitropyrene, 1,8‐dinitropyrene, 2‐nitrofluorene, and 4‐nitrobiphenyl were incubated with cultures of Chinese hamster ovary cells. The frequency of sister chromatid exchange (SCE) was measured in the presence and absence of rat liver S‐9 mix. The addition of S‐9 mix resulted in a large increase in the SCEs induced by all

ISSN:0192-2521    

DOI:10.1002/em.2860040102

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe cytotoxicity and mutagenicity of dimethylnitrosamine (DMN) was determined in the CHO/HGPRT system. Metabolic activation of the promutagen was achieved by use of a liver homogenate supernatant (S9) prepared from Aroclor 1254‐induced Sprague‐Dawley rats. The cytotoxic and mutagenic effects of DMN were enhanced by the inclusion of calcium chloride in the incubation mix, and this enhancement was dependent on the presence of sodium phosphate. Under conditions that yielded maximal activity (10 mM calcium chloride, 10 mM magnesium chloride, 50 mM sodium phosphate), an apparent calcium phospate precipitate was observed. DMN activity increased with increasing amounts of S9 protein over the range 0.3–3.0 mg/ml in the S9 mix and appeared to plateau at higher concentrations. The mutagenicity of DMN can be described as 110 mutants/106cells per mM DMN per mg/ml S9 protein per

ISSN:0192-2521    

DOI:10.1002/em.2860040103

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe Salmonella/microsome test and the chick embryo test were used to determine the mutagenicity and toxicity of five aflatoxin B1precursors. A definite pattern emerges: the nearer to B1an intermediate appears in the biosynthetic pathway, the more potent is its mutagenicity and toxicity.

ISSN:0192-2521    

DOI:10.1002/em.2860040104

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

年代:1982

数据来源: WILEY

摘要:

AbstractBleomycin, a radiomimetic glycopeptide, inhibits de novo DNA synthesis in ataxia telangiectasia lymphoblastoid B cells to a markedly lesser extent than in normal and xeroderma pigmentosum lymphoid cells. This observaton is similar to that following ionizing radiation; however, the effect is slower following the chemical treatment. Recovery of the normal cells occurs 15–18 hours after treatment, whereas the ataxia telangiectasia lines do not attain normal levels of DNA synthesis during the entire 24‐hour observation period. Similar differences were not observed following treatment with mitomycin C, a bifunctional alkylating agent, indicating a specific effect of bleomycin on DNA synthesis in ataxia telangiectasia cells. Following bleomycin treatment and preincubation with hydroxyurea, residual DNA synthesis in ataxia telangiectasia cells was similar to that in both normal and xeroderma pigmentosum lymphoid lines, suggesting that the capacity to repair the induced DNA lesion is pres

ISSN:0192-2521    

DOI:10.1002/em.2860040105

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe genotoxicity of airborne organic particles from forest fire smoke was compared to that from nonsmoky (ambient) urban air using the Salmonella reversion assay and the sister chromatid exchange (SCE) assay in cultured human lymphocytes. Salmonella strains TA98 and TA100 were used with and without the addition of Aroclor‐induced rat liver homogenate (S9). Each sample induced dose‐related increases in mutagenicity and SCE. However, on the basis of the volume of air sampled, the smoke‐filled air induced 12 to 14 times more bacterial reversions in TA100 and 16–38 times more reversions in TA98 than ambient air. Similarly, on a volume basis smoky air induced 43 times more SCE in human lymphocytes than did ambient air. The results indicate that the increased mutagenicity was due not only to the heavier particulate load of the air, but also to the increased specific mutagenicity of the pa

ISSN:0192-2521    

DOI:10.1002/em.2860040106

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

年代:1982

数据来源: WILEY

摘要:

AbstractCrude extracts from maize plants treated with varying concentrations of AAtrex, an s‐triazine herbicide, were tested for the induction of gene conversion in a diploid strain of Saccharomyces cerevisiae heteroallelic at two loci. These extracts were then subjected to analysis by high pressure liquid chromatography (HPLC), and the fractions collected in water, 50% methanol, and 100% methanol were similarly tested. Dose‐dependent convertogenic activity observed in the 50% methanol fractions suggested that the mutagen(s) is recovered in this fract

ISSN:0192-2521    

DOI:10.1002/em.2860040107

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

年代:1982

数据来源: WILEY

摘要:

AbstractA method is described in which primary rat hepatocytes have been cocultured with Chinese hamster ovary (CHO) cells to provide metabolic activation of promutagens in the Chinese hamster ovary/hypoxanthine‐guanine phosphoribosyl transferase (CHO/HGPRT) mutational assay. Single cell hepatocyte suspensions were prepared from male Fischer‐344 rats using the in situ collagenase perfusion technique. Hepatocytes were allowed to attach for 1.5 hours in tissue culture dishes containing an approximately equal number of CHO cells in log growth. The cocultures were exposed to promutagens for up to 20 hours in serum‐free medium. The survival and 6‐thioguanine‐resistant fraction of treated CHO cells were then determined as in the standard CHO/HGPRT assay. Aflatoxin B1(AFB1) 7,12‐dimethylbenz(a)anthracene (DMBA) and benzo(a)pyrene (B(a)P) were found to produce increases in the mutant fractions of treated CHO cells as a function of concentration. The time required for optimum expression of the mutant phenotype following exposure to DMBA and AFB1was approximately 8 days. Primary cell‐mediated mutagenesis may be useful in elucidating metabolic pathways important in the production and detoxification of genotoxic pro

ISSN:0192-2521    

DOI:10.1002/em.2860040108

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

年代:1982

数据来源: WILEY

摘要:

AbstractHuman lymphocytes and Chinese hamster ovary cells were exposed to DNA damaging agents for two cell cycles, and the induced sister chromatid exchange (SCE) rate was compared. CHO cells showed a significant increase in SCE following treatment with bleomycin and vincristine whereas human lymphocytes did not. Both CHO cells and lymphocytes showed an increase in SCE with 5‐bromode‐oxyuridine (BrdUrd) and tritiated uridine (3H‐Urd) but the increase was greater in CHO cells. SCE levels were similar after exposure to proflavine and colcemid did not increase the exchange frequency in either cell type. Apparently CHO cells are more sensitive than human lymphocytes to the actions of bleomycin, vincristine, BrdUrd, and3H‐Urd. SCE analysis in response to mutagens and carcinogens should therefore be based on more than one ce

ISSN:0192-2521    

DOI:10.1002/em.2860040109

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

年代:1982

数据来源: WILEY

摘要:

Abstract12‐O‐Tetradecanoyl‐phorbol‐13‐acetate (TPA) in conditions that produce enhancement of ultraviolet light (UV) and x‐irradiation Syrian hamster embryo cell (HEC) transformation did not cause further increase in the sister chromatid exchange (SCE) frequency induced by UV and x‐irradiation, two physical carcinogens that differ in their mode of DNA interaction and efficiency of SCE induction. Several factors which might influence SCE induction by TPA were studied on HEC and Chinese hamster V79‐4 cells. Heat‐inactivated serum was used because of the possibility that a serum component may interfere with TPA ability to cause SCE. TPA effect on SCE was determined at the first and second division post treatment on cells exposed to different 5‐bromodeoxyuridine (BrdUrd) concentrations. Independent of BrdUrd concentration (1‐10μg/ml medium) and the number of cell divisions post treatment, TPA (0.01‐2μg/ml medium) was ineffective in inducing SCE in exponentially and stationary HEC cultures cultivated in medium supplemented with heat‐inactivated serum. Also, TPA did not increase the SCE frequency in V79‐4 Chinese hamster cells cultured in heat‐inactivated or noninactivated serum. Although SCE induction, a cellular response to carcinogen‐induced DNA damage, may be important for the induction of transformation by environmental agents, the enhancement of transformation frequency caused by TPA occurs without further DNA alte

ISSN:0192-2521    

DOI:10.1002/em.2860040110

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe effects of tartar emetic and bilharcid, two antimonial antibilharzial drugs, on the chromosomes of laboratory rats are studied. The drugs were administered intraperitoneally in three doses—clinical, intermediate, and maximum tolerated — both acutely (6, 24, and 48 hours) and subacutely. The two drugs produced the same types of chromosomal aberrations with tartar emetic, inducing a higher rate of incidence. No significant differences in the number of cells with chromosomal aberrations were generally observed among the 6, 24, and 48 hours of the acute treatment with both tartar emetic and bilharcid. The dose‐response relationship was examined for both the acute and the subacute treatments. Whereas the acute treatment of tartar emetic showed a dose‐dependent linear increase in the number of cells with chromosomal aberrations, the subacute treatment of tartar emetic and the acute and subacute treatments of bilharcid displayed their maximum effects at an intermedia

ISSN:0192-2521    

DOI:10.1002/em.2860040111

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

年代:1982

数据来源: WILEY