摘要:

AbstractThe molecular nature of formaldehyde (HCHO)‐induced mutations was studied in both human lymphoblasts andE. coli. Thirty HPRT−human lymphoblast colonies induced by eight repetitive 150 μM HCHO treatments were characterized by Southern blot analysis. Fourteen of these mutants (47%) had visible deletions of some or all of the X‐linked HPRT bands, indicating that HCHO can induce large losses of DNA in human lymphoblasts. InE. coli, DNA alterations induced by HCHO were characterized with use of the xanthine guanine phosphoribosyl transferase (gpt) gene as the genetic target. Exposure ofE. colito 4 mM HCHO for 1 hr induced large insertions (41%), large deletions (18%), and point mutations (41%). Dideoxy DNA sequencing revealed that most of the point mutations were trans versions at GC base pairs. In contrast, exposure ofE. colito 40 mM HCHO for 1 hr produced 92% point mutations, 62% of which were transitions at a single AT base pair in the gene. Therefore, HCHO is capable of producing different genetic alterations inE. coliat different concentrations, suggesting fundamental differences in the mutagenic mechanisms operating at the two concentrations used. Naked pSV2gpt plasmid DNA was exposed to 3.3 or 10 mM HCHO and transformed intoE. coli. Most of the resulting mutations were frameshifts, again suggesting a different mutagenic mec

ISSN:0192-2521    

DOI:10.1002/em.2860120202

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

年代:1988

数据来源: WILEY

摘要:

AbstractTypes and frequencies of structural aberrations in human sperm and lymphocyte chromosomes from one donor were compared after in vitro irradiation with 100, 200, and 400 rad in order to determine if cells with dramatically different chromatin configurations are similarly affected and to investigate the feasibility of using lymphocytes as surrogates for germ cells in risk estimation. Sperm chromosomes were analyzed after fusion with eggs from the golden hamster. Total frequencies of induced aberrations were similar in the two cell types. However, the relative frequencies of rejoined lesions (dicentrics), compared with unrejoined lesions (chromosome breaks and acentric fragments), were different. At the three doses tested, a constant ratio of 5 dicentrics in lymphocytes for every dicentric in sperm was induced. Conversely, for every chromosome break or acentric fragment induced in lymphocytes, 1.7 such events were induced in sperm at the three doses tested.

ISSN:0192-2521    

DOI:10.1002/em.2860120203

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe incidence of sister chromatid exchange (SCE) was investigated in the lymphocytes of control women, pregnant women, and women using oral contraceptives after culture at 37°C and 40°C. At 37°C, the mean frequency of SCE (MEAN ± S.E.) was found to be 7.91 ± 0.30 in pregnant women and 8.53 ± 0.29 in oral contraceptive users which were significantly higher than the SCE value of 5.56 ± 0.21 found in control women. Increase in growth temperature to 40°C elevated the SCE frequency to 11.86 ± 0.44 in pregnant women, 12.76 ± 0.46 in oral contraceptive users and 7.24 ± 0.26 in control women. These data indicate that there is a differential induction of SCEs following increased cell culture temperature in the lymphocytes of pregnant women and oral contraceptive users, compared with con

ISSN:0192-2521    

DOI:10.1002/em.2860120204

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

年代:1988

数据来源: WILEY

摘要:

AbstractMale C57B1/6 mice were injected i.p. with either 1.25 or 5.0 mg/kg diaziquone (AZQ) and killed at various time intervals from 1 to 99 days post treatment for examination of sister chromatid exchange (SCE) persistence in the peripheral blood lymphocytes (PBLs) and splenocytes. SCE frequencies were found to decay steeply during the first week after exposure in both PBLs and splenocytes. This pattern was followed by a slower decline to baseline over the next week. However, high‐frequency cell (HFC) analysis indicates that significant numbers of HFCs persist in the PBLs through day 28 and splenocytes at day 99 post exposure. Mathematical modeling of the time‐response curves indicates that the average life span of the majority of AZQ‐induced SCE‐producing lesions in murine PBLs and splenocytes responsive to phytohemagglutinin is between 3 and

ISSN:0192-2521    

DOI:10.1002/em.2860120205

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

年代:1988

数据来源: WILEY

摘要:

AbstractEnhanced reactivation of Ultraviolet‐irradiated virus has been reported to occur in heat‐shocked host cells. Since enhanced virus reactivation is often accompanied by untargeted mutagenesis, we investigated whether such mutagenesis would occur for herpes simplex virus (HSV) in CV‐1 monkey kidney cells subjected to heat shock. In addition to expressing enhanced reactivation, the treated cells were transiently more susceptible to infection by unirradiated HSV. No mutagenesis of unirradiated HSV was found whether infection occurred at the time of increased susceptibility to infection or during expression of enhanced viral reactiv

ISSN:0192-2521    

DOI:10.1002/em.2860120206

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

年代:1988

数据来源: WILEY

摘要:

AbstractSister chromatid exchange (SCE) and cell‐cycle kinetics were examined at near‐baseline levels in human peripheral lymphocytes exposed to low doses of the potent SCE inducer 1‐(2‐chloroethyl)‐3‐cyclohexyl‐1‐nitrosourea (CCNU), in vitro. A preliminary SCE dose‐response curve was determined with a broad range of doses of CCNU using a single donor. SCE induction was approximately linear over the entire dose range from 5 to 200 μM CCNU. Cell cycle kinetics were retarded in a dose‐dependent manner. A second dose‐response curve from the same donor was constructed using several doses of CCNU between 0.5 and 10 μM to evaluate linearity and uniformity of SCE response near baseline levels. SCE induction was approximately linear between 1.0 and 10.0 μM CCNU. Finally, SCE and cell‐cycle kinetics were examined in 12 donors at doses of 1.0, 5.0, and 10.0 μM CCNU to evaluate the reproducibility of near‐baseline SCE induction over a range of subjects. Cell‐cycle kinetics were retarded at all three doses with a highly significant increase in SCE frequencies at 5.0 and 10.0 μM CCNU. These data suggest that increases in SCE less than twice background can be reliable

ISSN:0192-2521    

DOI:10.1002/em.2860120207

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

年代:1988

数据来源: WILEY

摘要:

AbstractTwo dyes (C.I. Solvent Yellow No. 33 and a mixture of C.I. Solvent Yellow No. 33 and C.I. Solvent Green No. 3) were tested for mutagenicity in the Salmonella reversion assay and the L5178Y/TK±mouse lymphoma assay, and also for sister chromatid exchange (SCE) induction in vivo in C57B1/6J mice. In addition, a>99.9% pure sample of the yellow dye [2‐(2′‐quinolyl)‐1,3‐indandione] was tested with and without exogenous activation in the Salmonella reversion assay and the L5178Y/TK±mouse lymphoma assay. Neither C.I. Solvent Yellow No. 33 nor the C.I. Solvent Yellow No. 33 and Solvent Green No. 3 mixture was positive for inducing SCEs in vivo. All three dyes were tested in the standard plate incorporation test in seven Salmonella strains TA98, TA100, TA102, TA104, TA1535, TA1537, and TA1538. The dyes were negative with and without exogenous activation in TA98, TA1535, and TA1538. One test with TA1537 was positive with the>99.9% purified yellow dye. All three dyes gave weakly positive results (less than a twofold increase) with S‐9 in TA100 and were clearly positive in TA102 and TA104 both with and without S‐9. They also induced mutation at the thymidine kinase

ISSN:0192-2521    

DOI:10.1002/em.2860120208

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe genotoxic effects of five pesticides (benomyl, 2,4‐D, dimecron, monocrotophos, and vitavax) were evaluated in the rat bone marrow cytogenetic assay. The spectrum of aberrations observed included chromatid breaks, chromatid fragments, ring chromosomes, dicentric chromosomes, and chromosome fragments. It was observed that 2,4‐D, dimecron, and vitavax were clastogenic, but the results obtained with benomyl and monocrotophos were equivo

ISSN:0192-2521    

DOI:10.1002/em.2860120209

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe rat liver carcinogen methapyrilene is shown to be a selective mutagen to strain TA1535 ofSalmonella typhimuriumwhen tested in the absence of S9 mix and using the standard plate‐incorporation assay protocol. The activity observed was weak but was reproducible for a range of samples on many occasions of test and was not due to impurities. These data contrast with six earlier reports of the inactivity of this chemical in theSalmonellamutation assa

ISSN:0192-2521    

DOI:10.1002/em.2860120210

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

年代:1988

数据来源: WILEY

摘要:

Abstract1,2,3‐Tribromopropane, 1,2,3‐trichloropropane, and 1,2‐dibromo‐3‐chloropropane are mutagenic in strains TA1535 and TA100 ofSalmonella typhimurium, but only in the presence of rat liver S9 mix. This requirement for metabolic activation was unexpected for an alkyl halide and thus suggested the metabolic formation of the 2‐keto derivatives (di‐haloacetone). The 2‐methyl derivatives of the halopropane compounds did not induce a doubling of revertants compared to controls. It was demonstrated that none of these compounds is converted into a secondary material that could be determined as structurally different by gas chromatography. These observations suggest that lack of mutagenicity of the methylated compounds is a manifestation of

ISSN:0192-2521    

DOI:10.1002/em.2860120211

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

年代:1988

数据来源: WILEY