The beginnings of the first animal model appreciated for its macroscopic and histological similarity to human colorectal carcinoma (CRC) extend to 1963, when Laqueur discovered that rats fed cycasin, a plant product, developed intestinal cancer. The active substance was identified and soon a similar compound, methylazoxymethanol acetate (MAMA) was synthesized that was more effective than the na...

To study the effect of deuterium substitution on the carcinogenicity of 1,2-dimethylhydrazine (DMH) in mice, two comparisons were made between DMH and its fully methyl-deuterated analogue, [2H6]DMH. In a lifetime study with the CBA strain, groups of 19-30 animals of each sex were dosed s.c. weekly with 8 mg/kg of either DMH or [2H6]DMH for 8, 16, or 32 weeks. In the second study, female CF-1 mi...

PURPOSE In this study the influence of moderate or intense physical exercise, alone or in combination with the consumption of a soya product fermented with Enterococcus faecium, on the development of colon cancer induced chemically in rats with 1,2-dimethylhydrazine (DMH), was investigated. METHODS Eighty male Wistar SPF rats were randomly allocated to 8 groups (n = 10). One week after the st...

Tumor promotion associated with increased dietary fat may be inhib ited by reduction in total caloric intake. This hypothesis was tested in rats given either 7,12-dimethylbenz(fl)anthracene to induce mammary tumors or 1,2-dimethylhydrazine to induce colon tumors. One week after dosage with either carcinogen, the rats were fed semipurified diets that provided 4% fat with ad libitum calories or 1...

Young adult male rats received 1,2-dimethylhydrazine (25 mg/kg) twice weekly for 2 months and once a week thereafter for up to 6 months. Histological samples of duodenum, jejunum, and upper, mid-, and terminal ileum were prepared from groups killed at each month. Using cell counts, the average number of epithelial cells was determined per representative section of villi and crypts and was used ...

There is much evidence suggesting a possible role of reactive oxygen-derived substances in the pathogenesis of both ulcerative colitis and colon cancer. The antioxidant effects of 5-aminosalicylic acid (the active moiety of olsalazine) on induction of colon cancer in an experimental model using 1,2-dimethylhydrazine were studied in male Wistar rats. The levels of reduced glutathione were signif...