ISSN:0192-2521    

DOI:10.1002/em.2860090102

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

年代:1987

数据来源: WILEY

摘要:

AbstractIn vivo systems for analyzing mutagen interactions with a specific differentiating cell population are rare. Taking advantage of the unique anatomical features of the bursa of Fabricius in the chicken, we explored the possibility of targeting chemical mutagens to a defined differentiating cell population in the animal, namely, the B‐lymphocytes series. Such cells are known to be the targets for the oncogene‐activating avian leukosis virus. Targeting of chemicals to cells of the bursa was demonstrated by application of the DNA‐specific fluorochrome 4′‐6‐diamidino‐2‐phenylindole (DAPI) to the anal lips of neonatal chicks. Bright nuclear fluorescence of cells in the bursa was demonstrated to occur within minutes after the application of 500 m̈l of DAPI. DAPI labeling of nuclei was detected up to several days after a single application. No nuclear labeling was exhibited in cells of neighboring tissues. Methyl methanesulfonate (MMS) (10 m̈l) was applied to the anal lips of day‐old chicks to study dose‐response kinetics for mutagen targeting to DNA of dividing B‐lymphocytes in the bursa. Since the mitotic index was found to be quite high (25‐30%) in the bursa, chromosome analysis was used to assay for genome damage. Sister chromatid exchange frequencies of 3.9, 7.3, and 9.0 (baseline 2.5) per cell were obtained at MMS dosages per animal of 50 m̈g, 100 m̈g, and 200 m̈g, respectively. These results indicate the rapid and quantitative localization of DNA‐binding chemicals to cells of the bursa, particularly the resident B‐lymphocytes. The bursa should be a useful system for studying mutagen‐DNA interactions in the differentiating B‐lymphocyte and subsequent influences on the development of immu

ISSN:0192-2521    

DOI:10.1002/em.2860090103

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

年代:1987

数据来源: WILEY

摘要:

AbstractThe genotoxic effects of methyl isocyanate (MIC) were investigated using four short‐term tests: theSalmonellareversion assay (Ames test), theDrosophilasex‐linked recessive lethal assay, and the sister chromatid exchange (SCE) and chromosomal aberration assays in cultured Chinese hamster ovary (CHO) cells. No evidence was found for the induction of mutations in eitherSalmonellaorDrosophila.MIC did, however, induce SCEs and chromosomal aberrations in CHO cells both in the presence and absence of Aroclor‐induced rat live

ISSN:0192-2521    

DOI:10.1002/em.2860090104

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

年代:1987

数据来源: WILEY

摘要:

AbstractMice were exposed to 1, 3, or 6 ppm methyl isocyanate (MIC) for 6 hr/day for four consecutive days. Lung cells and peripheral blood lymphocytes (PBLs) were removed and cultured for analysis of sister chromatid exchange (SCE) and cell cycle kinetics. MIC caused a small but significant increase in SCE frequency of cultured lung cells from mice exposed to 1, 3, or 6 ppm MIC. MIC did not significantly increase SCE levels in PBLs of mice exposed to concentrations as high as 6 ppm. In cultured PBLs, MIC had a stimulatory effect on cell cycling rates as measured by the replicative index, and it caused a significant reduction in mononuclear leucocyte counts and the mitotic indices.

ISSN:0192-2521    

DOI:10.1002/em.2860090105

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

年代:1987

数据来源: WILEY

摘要:

AbstractThe ability of inhaled methyl isocyanate (MIC) to induce genotoxic and cytotoxic damage in vivo was evaluated by assessing the induction of chromosomal aberrations (CAs) and sister chromatid exchanges (SCEs) in bone marrow metaphase cells, the induction of micronuclei in polychromatic erythrocytes (MN‐PCEs), and the inhibition of bone marrow cellular proliferation and erythropoiesis. B6C3F1 mice were exposed to MIC by two exposure regiments: (a) in two experiments, male mice only were exposed to 3, 10, and 30 ppm for 2 hr(b) in four experiments, male and female mice were exposed to 1 and 3 ppm (in one experiment, to 6 ppm, also, 6 hr per day for 4 consecutive days. The various cytogenetic endpoints were analyzed in bone marrow and peripheral blood (4‐day exposure regimen only) samples taken from bromodeoxyuridine tablet‐implanted animals killed 11 to 22 hr after cessation of the exposure to MIC. Exposure to MIC for 2 hr induced a significant delay in cellular proliferation but did not induce a significant increase in CAs, SCEs (evaluated at 3 and 10 ppm, only) or in bone marrow MN‐PCEs. Also, this exposure regimen did not inhibit the rate of erythropoiesis. Following exposure to MIC for 4 days, a weak but significant increase in CAs and SCEs was observed in male (in one experiment) and in female (in two experiments) mice. The induction was especially apparent in the single experiment in which mice were exposed to 6 ppm MIC. At this concentration, a significant increase in MN‐PCEs in peripheral blood was observed in male but not female mice. Delay in bone marrow cell proliferation was observed in male mice beginning at 3 ppm and in female mice at 6 ppm. The 4‐day exposure regimen resulted also in a depressed rate of erythropoiesis, with male mice appearing to exhibit greater depression than female mice. The results demonstrate that exposure to MIC by inhalation results in bone marrow damage, indicating the systemic genotoxic/cytotoxic activity of MIC and/or reactive

ISSN:0192-2521    

DOI:10.1002/em.2860090106

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

年代:1987

数据来源: WILEY

摘要:

AbstractThe response of BALB/3T3 clone A31‐1‐1 cells to chemically induced morphological transformation was evaluated using 3‐methylcholanthrene (MCA). Stock cultures were initiated from cryopreserved cells, grown in T25 flasks containing 5 ml of medium, and replated at subconfluency. Serially transferred cells were then subjected to transformation assay. After 24‐hr seeding, cells were incubated 48 hr with MCA in a 5% CO2incubator. They were then rinsed and incubated for an additional 4 weeks with twice weekly medium change. Type III foci were scored after fixation and staining with Giemsa. With serial passage from the frozen state, cells of passages 3‐14 had a low level of spontaneous transformation; zero to 6 type III foci per 20 dishes were counted. In the MCA‐treated cultures the number of transformed foci, however, increased with passage. Such passage‐related sensitivity to MCA was demonstrated for cells cultured in two batches of sera: one from MA Bioproducts (Lot no. 2E052) and the other from Armour Pharmaceuticals (Lot no. Y65801). The passage‐related increase in number of transformed foci was not related to doubling time, cloning efficiency, or MCA‐induced

ISSN:0192-2521    

DOI:10.1002/em.2860090107

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

年代:1987

数据来源: WILEY

摘要:

Abstractp‐Rosaniline was fed to male and female Fischer 344 rats and B6C3F1 mice at doses of 1,000 and 2,000 ppm for male rats and 500 and 1,000 ppm for female rats and mice of both sexes. Urine was collected overnight at 1‐wk intervals over a 4‐wk treatment period and frozen until its use in the mutagenicity assay. The neat urine was tested in triplicate without S‐9 onSalmonellatester strains TA98, TA100, TA1535, and TA1537 at 0.75, 0.5, 0.2, and 0.05 ml per plate. When sufficient urine was available, samples were tested on TA100 in the presence of S‐9. Either urine samples were pretreated for 18 hr at 37°C with β‐glucuronidase, or the deconjugating enzyme was added to the top agar at the time of plating in the mutagenicity assay (non‐pretreatment). Direct‐acting mutagenic activity was detected on TA98 in the urine from male mice, but only when using the non‐pretreatment deconjugation method. No direct‐acting mutagenic activity was detected in the urine of male and female rats and female mice; however, in the presence of S‐9, mutagenic activity was observed in the urine of male rats and in the urine of male and female mice regardless of the deconjugation method used. The non‐pretreatment method was superior for detecting direct acting mutagenic activity, and the pretreatment method was superior for detecting mutagenic activity requiring me

ISSN:0192-2521    

DOI:10.1002/em.2860090108

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

年代:1987

数据来源: WILEY

摘要:

AbstractSperm abnormalities in mice induced by IP injection of quercetin at total cumulative doses of 16, 32, 80, and 160 mg/kg b. wt. administered fractionally on 5 successive days were quantitated by assessing the percent of sperm with abnormal heads or tails. Five weeks after the final injection a maximum of 14.8% abnormal sperm were observed with a total quercetin dose of 80 mg/kg b. wt. compared to the spontaneous control of 0.98%. Concomittantly, a 32.1% reduction in testicular weight occurred compared to control mice which was coincident with a reduction in sperm count of 28 %.

ISSN:0192-2521    

DOI:10.1002/em.2860090109

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

年代:1987

数据来源: WILEY

ISSN:0192-2521    

DOI:10.1002/em.2860090110

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

年代:1987

数据来源: WILEY

ISSN:0192-2521    

DOI:10.1002/em.2860090111

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

年代:1987

数据来源: WILEY