摘要:

AbstractWe have investigated the effect of caffeine on embryo growth and development. Caffeine (25 mg/kg) was administered on gestation day (g.d.) 8–9 and the embryos examined histologically 24 h after the final dose. The crown‐rump length of caffeine treated embryos (1.92 ± 0.08 mm) was significantly smaller (P<0.001) than the controls (2.91 ± 0.26 mm) as was the circumferential length (caffeine vs. controls, 3.79 ± 0.16 mm vs. 6.03 ± 0.61 mm;P<0.001). Additional measures, such as development of the heart, eye, and limb buds, were also reduced in the caffeine treated embryos. The most striking difference between the control and caffeine treated embryos was the larger proportion of treated embryos with regions of open neural tube. This was most marked in the caudal region of the embryos where 91% of treated embryos had regions of open neural tube compared with 14% of controls. The amount of open neural tube in any individual caffeine treated embryo did not relate to the crown‐rump or circumferential length of that embryo nor was the effect restricted to particular litters. These results indicate that caffeine had a significant effects on embryonic growth and development. © 1994 Wiley

ISSN:0270-3211    

DOI:10.1002/tcm.1770140502

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

年代:1994

数据来源: WILEY

摘要:

AbstractBrain tumours are of different cell types, the commonest being tumours of glia called gliomas. Many etiological factors of gliomas have been suggested and certain industries have been implicated. Several epidemiological studies have linked electromagnetic fields (EMFs) to gliomas. Health effects of EMFs have been studied, both in humans and in experimental animals, mainly with negative findings. Positive experimental evidence linking EMFs to tumours is the effect of EMFs on melatonin production by the pineal gland. Removal of the pineal gland in rats increases the incidence of tumours. Further epidemiological and experimental evidence is required to elucidate this possible link between EMFs and brain tumours. © 1994 Wiley‐Liss, I

ISSN:0270-3211    

DOI:10.1002/tcm.1770140503

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

年代:1994

数据来源: WILEY

摘要:

AbstractA data base consisting of 100 chemicals tested for the ability to enhance the formation of glutathione‐S‐transferase (GST) positive preneoplastic lesions were analyzed by the CASE structure‐activity relational system. A number of structural determinants associated with the induction of GST‐positive foci were recognized. The majority of these describe non‐electrophilic moieties. It is concluded that there is a structural basis for the induction of these neoplastic lesions; interestingly, it was found that this activity is associated with structures that are non‐electrophilic. Reconstruction experiments have indicated that the identified structures are meaningful and that their significance could be better understood with the availability of test results on additional chemicals. © 1994 Wil

ISSN:0270-3211    

DOI:10.1002/tcm.1770140504

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe effects of policosanol (50–500 mg/kg) administered orally for 24 months to Sprague Dawley rats of both sexes were investigated. No differences related to daily clinical observations, weight gain, food consumption, or mortality (survival analysis) between groups were found. Histopathological study showed that the frequency of the occurrence of non‐neoplastic and neoplastic (benign and malignant) lesions was similar in the control and policosanol‐treated groups. The lesions observed in this study were similar to the spontaneous lesions reported in this species in previous studies. Since no drug‐related increase in the occurrence of malignant or benign neoplasms was found, nor acceleration in tumors growth in any specific group was observed, this study shows no evidence of policosanol induced carcinogenicity in this strain of rats. © 1994 Wiley

ISSN:0270-3211    

DOI:10.1002/tcm.1770140505

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

年代:1994

数据来源: WILEY

ISSN:0270-3211    

DOI:10.1002/tcm.1770140501

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

年代:1994

数据来源: WILEY