摘要:

AbstractGuinea pigs were exposed to hyperthermia for 1 hr once or twice on day 11, 12, 13, or 14 (E11–E14) of pregnancy. The mean rectal temperatures were elevated by 3.4°C–4.0°C. This treatment resulted in a marked elevation of rates of resorption and developmental defects in embryos examined at day E23. The defects observed were those affecting the neural tube (NTD) (exencephaly, encephaloceles, and microphthalmia), kyphosis/scoliosis, branchial arch defects, and pericardial edema. Embryos with NTD and kyphosis/scoliosis have not been found among newborn guinea pigs to date following maternal heat exposure on days E12–E14. It appears that embryos with these defects are filtered out by resorption or abortion by days E30–E35. © 1992 Wiley

ISSN:0270-3211    

DOI:10.1002/tcm.1770120102

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe modulatory effect of vitamin C (Vit C) on the mutagenic effect of the antineoplastic drug cyclophosphamide (CP) was assessed in the in vivo micronucleus test in Swiss mice. Simultaneous oral administration of Vit C with i.p. administration of CP was found to decrease the frequency of micronucleated polychromatic erythrocytes elevated by CP. Vit C exhibited a significant antimutagenic effect over a wide dose range (1.56–200 mg/kg). The dose‐response relationship was highly significant. These results demonstrated the ability of the in vivo micronucleus test to detect in vivo modulation of CP mutagenicity by Vit C. Our earlier results and those from other laboratories also indicate that this model system is suitable for primary in vivo screening of modulation of mutagenesis. © 1992 Wiley‐Lis

ISSN:0270-3211    

DOI:10.1002/tcm.1770120103

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

年代:1992

数据来源: WILEY

摘要:

AbstractEffects on renal development were studied using tobramycin (TBM) as a model compound. Pregnant Sprague‐Dawley rats were injected i.p. with TBM at 30 or 60 mg/kg body weight/day on gestational days (GD) 10–19. Kidneys from dams and conceptuses were examined on GD 20 and on postnatal day (PD) 9. The dosing regimen caused in dams moderate proximal tubular alterations and increased concentrations in serum creatinine. Fetal kidneys showed granularity and swelling of proximal tubule cells at the 30 mg/kg dose, poor glomerular differentiation at the 60 mg/kg dose, increased glomerular density at both doses, and no changes on macroscopic examination at either dose. In newborns were observed a moderate developmental delay and tubular lesions at the higher dose, and dose‐related increases of glomerular density and relative medullary area at both doses. All findings were more pronounced in males. A maturational disruption of the tubular structures possibly leading to increased glomerular density was attributed to TBM exposure during renal organogenesis in the rat. © 1992 Wiley‐L

ISSN:0270-3211    

DOI:10.1002/tcm.1770120104

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

年代:1992

数据来源: WILEY

摘要:

Abstract2‐Chlorethanol, 8‐hydroxyquinoline, 2,6‐toluenediamine, and eugenol, previously found to behave as genotoxins in in vitro systems and as noncarcinogens in rodents, were evaluated for their ability to induce genotoxic effects in vivo. Rats were given by gavage a single or two successive doses equal to one‐half the corresponding LD50, killed at different times after treatment, and examined for the following end points: the frequency of both micronucleated polychromatic erythrocytes in the bone marrow and micronucleated hepatocytes (after partial hepatectomy); the in vivo—in vitro induction of DNA fragmentation, as measured by the alkaline elution technique, and of unscheduled DNA synthesis, as measured by autoradiography, in hepatocyte primary cultures. The two latter end points were also evaluated after in vitro exposure of hepatocytes to log‐spaced subtoxic concentrations. 2‐Chloroethanol, 8‐hydroxyquinoline, and eugenol never produced effects indicative of genotoxic activity. The same happened with 2,6‐toluenediamine, with the exception of a significant increase over controls in the amounts of DNA damage and repair displayed by hepatocyte cultures obtained from rats given two 1/2 LD50 separated by a 24 h interval. Our results, which, apart the above mentioned exception, are in concordance with the rodent carcinogenicity results, contribute to underline the role of in vivo short‐term tests for the detection of potential genotoxic carcinogens. ©

ISSN:0270-3211    

DOI:10.1002/tcm.1770120105

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

年代:1992

数据来源: WILEY

摘要:

Abstract5,5‐Diphenylhydantoin (DPH) is an antiepileptic drug associated with an increase in malformations in infants born to women taking DPH during pregnancy. Positive and negative results have been reported by various investigators for in vivo and in vitro chromosome aberration (CAB) assays, in vivo and in vitro sister chromatid exchange (SCE) assays, and in vivo micronucleus tests (MNT). In this laboratory, DPH was tested in an in vitro CAB assay using Chinese hamster ovary cells with and wihout an S‐9 activation system, an in vivo SCE assay in female CD‐1 mice, an in vivo MNT, using both male and female CD‐1 mice, and a transplacental micronucleus test. The results from this comprehensive battery of cytogenetic tests were uniformly negative and support a conclusion that the known teratogen, DPH, is not clastogenic. © 1992 Wiley

ISSN:0270-3211    

DOI:10.1002/tcm.1770120106

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

年代:1992

数据来源: WILEY

ISSN:0270-3211    

DOI:10.1002/tcm.1770120101

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

年代:1992

数据来源: WILEY