摘要:

AbstractThree pairs of structurally similar carcinogenic/ non‐carcinogenic chemicals were tested for in vivo genotoxic activity in B6C3F1 mice. The carcinogenic/non‐carcinogenic pairs, respectively, were o‐toluidine hydrochloride/o‐anthranilic acid, 4‐chloro‐o‐phenylenediamine/4‐nitro‐o‐phenylenediamine, and 3‐(chloromethyl)pyridine hydrochloride/2‐(chloromethyl)pyridine hydrochloride. Bone marrow cells from mice given intraperitoneal injections of up to the maximum tolerated dose were evaluated for chromosomal aberration, sister chromatid exchange, and micronucleus induction, o‐anthranilic acid and o‐toluidine hydrochloride did not increase the frequency of chromosomal aberrations or micronuclei. o‐Toluidine hydrochloride increased the frequency of sister chromatid exchanges in two successive trials, while o‐anthranilic acid had a positive effect on sister chromatid exchanges in two of three trials. Both 2‐(chloromethyl) and 3‐(chloromethyl)pyridine hydrochloride were negative for all three endpoints. Assays for chromosomal aberrations and micronuclei each distinguished between 4‐chloro‐o‐phenylenedi‐amine and its non‐carcinogenic companion, 4‐nitro‐o‐phenylenediamine. In the aberration test, 4‐chloro‐o‐phenylenediamine produced a few cells with very large numbers of aberratio

ISSN:0893-6692    

DOI:10.1002/em.2850140402

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

年代:1989

数据来源: WILEY

摘要:

AbstractQuinoline is a specific and potent carcinogen to the rat and mouse liver. Studies are described here in which it was evaluated for its ability to initiate unscheduled DNA synthesis (UDS) in the rat liver in vivo. Although some individualanimalsshowed indications of a marginal response, the absence of cleargrouppositive responses and the lack of an obvious dose relationship precluded the classification of quinoline as positive. The analogous NTP non‐carcinogen 8‐hydroxy‐quinoline was shown also to be devoid of UDS activity. Quinoline did, however, induce a potent mitogenic response in the rat liver between 24 and 48 hr after oral dosing of 200–500 mg/kg. Under similar conditions of test, 8‐hydroxyquinoline was essentially inactive. These data represent a further instance in which mitogenicity in the liver appears to correlate better with carcinogenicity than does genotoxicity; but it may not be that simple, as discussed in the text. A single dose of quinoline was shown to act as a replacement for surgical partial hepatectomy in the liver micronucleus assay described by Tates, consistent with its potent mit

ISSN:0893-6692    

DOI:10.1002/em.2850140403

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

年代:1989

数据来源: WILEY

摘要:

AbstractIn order to characterize in vivo gene mutations that occur during fetal development, molecular analyses were undertaken of mutant 6‐thiogua‐nine resistant T‐lymphocytes isolated from placental cord blood samples of 13 normal male newborns. These mutant T‐cells were studied to define hypoxanthine‐guanine phosphoribosyl‐transferase(hprt)gene structural alterations and to determine T‐cell receptor (TCR) gene rearrangement patterns. Structuralhprtalterations, as shown by Southern blot analyses, occurred in 85% of these mutant clones. These alterations consisted mostly of deletion of exons 2 and 3. These findings contrast with the 10–20% of gross structural alterations (i.e., those visible on Southern blots) occurring randomly across the entire gene previously reported for T‐cell mutants isolated from normal young adults. Iterative analyses ofhprtstructural alterations and TCR gene rearrangement patterns show that approximately one‐third of the newborn derived mutants may have originated as pre‐ or intrathymichprtmutations. This too contrasts with previous findings in adults where the background in vivohprtmutations appeared to originate in post

ISSN:0893-6692    

DOI:10.1002/em.2850140404

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

年代:1989

数据来源: WILEY

摘要:

AbstractPrevious publications on the National Toxicology Program (NTP)‐sponsored mutagenicity testing program inDrosophiladealt with evaluations of chemicals following adult treatment (feed, injection). The current paper deals with a comparison between the laboratories at Brown University (BRU) and the University of Wisconsin at Madison (UWM) regarding the response of larvae to treatment with chemicals in the sex‐linked recessive lethal (SLRL) test and, where appropriate, the reciprocal translocation test as well. Dimethylnitro‐samine (DMN) and dimethylbenz(a)anthracene were used first as reference mutagens. Six coded compounds were then evaluated regarding their repeatability in the two laboratories; the compounds were benzo(a)pyrene, 3‐methylcholan‐threne, coumarin, quinoline, formaldehyde, and 9‐aminoacridine. It was concluded that at this time it would be imprudent to forgo larval treatment in cases where compounds proved negative after adult feeding. Accordingly, testing a series of 20 compounds negative after adult treatment is

ISSN:0893-6692    

DOI:10.1002/em.2850140405

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

年代:1989

数据来源: WILEY

摘要:

AbstractTwenty‐two chemicals were tested for mutagenicity in the sex‐linked recessive lethal (SLRL) mutation assay after being fed toDrosophila melanogasterlarvae. One compound, maleic hydrazide, was found to be mutagenic. It was tested for the ability to produce reciprocal translocations (RTs) and was positive in that assay as w

ISSN:0893-6692    

DOI:10.1002/em.2850140406

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

年代:1989

数据来源: WILEY

摘要:

AbstractCuman L, a dithiocarbamate fungicide, was tested for its ability to induce sex‐linked recessive lethals (SLRLs) and II‐III chromosome translocations inDrosophila melanogasterby the larval feeding method. The three concentrations of Cuman L, of 20, 40, and 60 μl/100 ml, induced significant (P<0.01) increases in SLRLs but failed to induce any translocat

ISSN:0893-6692    

DOI:10.1002/em.2850140407

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

年代:1989

数据来源: WILEY

摘要:

AbstractMeans to assess the toxicity of wastewaters are essential to implementing the Federal Clean Water Act. Health risk assessment based on single chemicals is limited by the number of chemicals that can be identified and to those chemicals for which toxicity data are available. Long‐term whole animal tests on large numbers of waste‐water samples are not practical. In this study, two short‐term tests, theSalmonellamutagenicity assay and the Chinese hamster ovary (CHO) cell assay for mutagenicity and cytotoxicity, were evaluated as potentially useful biomonitors of wastewaters. Standard assay protocols were modified to allow testing of up to 2.5 and 3.4 ml of unconcentrated water in the bacterial and mammalian cell tests, respectively. Cytotoxicity and mutagenicity were detected in some unconcentrated wastewater samples using these modifications. Data on eight wastewater samples, representing five different sites, indicated that theSalmonellatest is the more sensitive indicator of mutagenic activity in those samples, whereas the CHO test is a sensitive indicator of the presence of cytotoxic components. Wastewater concentrates, prepared by adsorption onto XAD‐2 and “blue cotton,” were compared in the two bioas‐says. In a single concentrate, the two short‐term tests detected distinctly different mutagens. Advantages of using the CHO‐AS52 cell line instead of the CHO‐K1BH4line for detecting wastewater mutagens were indicated. This study illustrates the complementary use of multiple bioassays and concentration methods to detect and characterize toxic compo

ISSN:0893-6692    

DOI:10.1002/em.2850140408

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

年代:1989

数据来源: WILEY

ISSN:0893-6692    

DOI:10.1002/em.2850140409

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

年代:1989

数据来源: WILEY

ISSN:0893-6692    

DOI:10.1002/em.2850140410

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

年代:1989

数据来源: WILEY

ISSN:0893-6692    

DOI:10.1002/em.2850140401

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

年代:1989

数据来源: WILEY