摘要:

AbstractWe examined the effect of different durations of exposure (20 sec to 24 hr) to (±) 7‐β,8α‐dihydroxy‐9α, 10α ‐epoxy‐7,8,9,10‐tetrahydrobenzo(a)pyrene (BPDE I) on the induction of transformation in C3H/10T1/2 cells and of mutations to 6‐thioguanine resistance in Chinese hamster ovary cells (CHO), as well as on BPDE I‐DNA binding in these two cell lines. A 20‐sec exposure of the cells to BPDE I was sufficient to induce mutations and morphological transformation in vitro. However, the transformation frequency in CH3 mouse‐embryo‐derived 10T1/2 cells increased twofold and the frequency of mutations in CHO cells sixfold when the exposure time to BPDE I was increased from 20 sec to 8 h. Cytotoxicity increased under similar conditions. A large number of BPDE I‐DNA adducts were formed in both cell lines within the first 15‐min of exposure of the cells to this ultimate carcinogen. The total covalent binding did not increase with longer than 15‐min incubation times. These results suggest that in addition to its covalent binding to DNA, BPDE I may influence other cellular mechanism(s) that are responsible for the initiation o

ISSN:0270-3211    

DOI:10.1002/tcm.1770080302

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

年代:1988

数据来源: WILEY

摘要:

AbstractWithin the past ten years, quantitative risk assessment has come to play a central role in the federal regulation of carcinogens. Federal agencies use quantitative risk both to set priorities and to establish exposure levels. The use of quantitative risk assessment is mandated by Executive Orders requiring performance of cost‐benefit analysis, although performance of assessments has often been ascribed to the Supreme Court decision in the 1980 “benzene” case.Quantitative risk assessment is a deeply flawed methodology with results that give a false sense of certainty and objectivity. Also, the nature of quantitative risk assessment methodologies currently in use makes it difficult for members of the public to scrutinize and assess regulatory actions.Quantitative risk assessment should not be used for regulation of carcinogens, especially not for establishing exposure levels. Instead, alternative methodologies should be utilized, which are appropriately reflective of uncertainty and which are more readily accessible to public scrutiny and particip

ISSN:0270-3211    

DOI:10.1002/tcm.1770080303

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

年代:1988

数据来源: WILEY

摘要:

AbstractGroups of five male HA (ICR) mice were injected intraperitoneally with 60, 150, 300, or 600 mg/kg body weight of ethyl methanesulfonate (EMS) or with saline vehicle. Each male was mated to two untreated females at 2 and 5 weeks after treatment. The two successive matings utilized sperm derived from post‐ and premeiotic germ cells, respectively. Progeny were evaluated for litter size, body weight, negative geotactic response, swimming patterns, limb use while swimming, water escape time, and open‐field motor coordination activity. Body weight, geotactic response, limb use, and open‐field behavior test results demonstrated that EMS causes heritable behavior mutations in both post‐ and pre‐meiotic germ cells. Among the tests that showed inherited differences between control and treated groups, the computer‐monitored open‐field behavior test was the mo

ISSN:0270-3211    

DOI:10.1002/tcm.1770080304

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe effect of heat‐shock treatment (42°C for 15 min) on the ability of four mutagens and carcinogens to induce hereditary bleaching inEuglena graciliscells was investigated. All four mutagens (treatment time: 1–24 h) tested after heat shock increased the frequency of bleached mutants ofEuglena grac

ISSN:0270-3211    

DOI:10.1002/tcm.1770080305

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

年代:1988

数据来源: WILEY

摘要:

AbstractFive ergot alkaloids, d‐lysergic acid derivatives, were tested for the induction of sister chromatid exchange (SCE) frequencies in cultured Chinese hamster ovary cells. The concentrations of the test substances ranged between 10−5and 10−8M. Ergotamine, ergonovine, and methylergonovine induced a significantly high number of SCEs at all the concentrations used, while with ergocristine this occurred only at the highest concentration. α‐Ergocryptine failed to induce SCEs at any concentration. It is therefore surmised that ergotamine, ergonovine, and methylergonovine are effective inducers, ergocristine is a weak inducer, and α‐ergocryptine is a noninducer in Chinese hamster ovary cel

ISSN:0270-3211    

DOI:10.1002/tcm.1770080306

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

年代:1988

数据来源: WILEY

ISSN:0270-3211    

DOI:10.1002/tcm.1770080301

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

年代:1988

数据来源: WILEY