摘要:

AbstractUsing repair‐proficient and repair‐deficient strains ofE.coli, we investigated the application of a liquid incubation assay to measure the DNA‐damaging activity of ethanol‐soluble fecal extracts. This method appears to be suitable for the study of a wide range of sample types. It was used to measure the DNA‐modifying activity of ethanol‐soluble fecal extracts from a group of European colorectal cancer patients. Data were compared with those from Europeans of similar age and sex distribution who did not have bowel cancer. We also studied groups of Maoris, Samoans, and European Seventh‐Day Adventists who followed an ovo‐lacto vegetarian diet. There are significant levels of DNA‐modifying materials in the feces of many Europeans on a mixed diet, regardless of whether or not they have cancer. The number of positive samples was less in the Polynesian groups, and there were no samples that could be unequivocally scored as positive in the Seventh‐Day Adventist groups. We conclude that diet can significantly reduce the level of ethanol‐soluble mutagens, at least in New Zealand Europeans. The data may provide an explanation for the reduced incidence of bowel cancer in Seventh‐Day Adventist groups.

ISSN:0163-5581    

DOI:10.1080/01635588509513844

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor

摘要:

AbstractThe effects of N‐(4‐hydroxyphenyl)retinamide (HPR), a synthetic analogue of vitamin A, on cell morphology, cell cycle kinetics, cytoplasmic matrix, and expression of murine mammary tumor virus (MuMTV) in MuMTV‐infected murine mammary tumor cells (GR‐3A) were determined. Cellular uptake of HPR was rapid and linear, with zero‐order kinetics, during the first 30 minutes of incubation. Flow cytometric analysis of cells treated with nontoxic levels of HPR (10μM)for 48 hours revealed a reduction in percent cells in the DNA synthetic (S) phase of the cell cycle with a concomitant increase in percent cells in the G, phase of the cell cycle. Dexamethasone‐stimulated MuMTV expression was not affected after 48 hours of HPR exposure, whereas the virus expression was significantly reduced in cells treated with HPR for seven days. The reduction in MuMTV expression was preceded by changes in cell morphology (decreased cell‐cell contact and reduced cell flattening) and altered F‐actin aggregation. Continuous exposure to HPR (10μM) for 14 days resulted in reduced cell proliferation rates and decreased cell plating efficiency of GR‐3A cells. Taken together, these results indicate that HPR is rapidly incorporated into GR‐3A cells and that the effects of HPR on celt profileration, cytoskeletal organization, and cell morphology appear to precede the effects of this retinoid on the expression of the etiological agent of murine mammary tumorigenesis, MuMTV.

ISSN:0163-5581    

DOI:10.1080/01635588509513845

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor

摘要:

Therapeutics in Terminal Cancer,Robert G. Twycross and Sylvia A. Lack, Pitman Publishing Limited, London, 207 pp., 1984*Vitamin Politics,John Fried, Prometheus Books, Buffalo, NY, 238 pp., 1984

ISSN:0163-5581    

DOI:10.1080/01635588509513846

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor