Two enzymes were examined as potential indicators of early precancerous changes. Ornithine decarboxylase, an enzyme normally associated with rapid cell division, is low in the rapidly dividing, cancer-susceptible colon. The level of this enzyme was also very high in the nondividing cells of the small intestines. Administration of an intestinal carcinogen, dimethylhydrazine, led to a large incre...

The formation and persistence of methylated purines was determined in mice that received a single s.c. injection of 1,2-[14C]dimethylhydrazine (15 mg/kg) and were allowed to survive for 12 or 60 hr. In mice with a low susceptibility to dimethylhydrazine-induced colon carcinogenesis (C57BL/Ha), concentrations of 7-methylguanine and O6-methylguanine in DNA of colon, ileum, and kidney were 40 to 6...

The effects of new antidiabetic drug Diabenol (9-beta-diethylaminoethyl-2,3-dihydroimidazo-(1,2-alpha)benzimidazol dihydrochloride) on life span and spontaneous tumor incidence in NMRI and transgenic HER-2/neu mice as well as on colon carcinogenesis induced by 1,2-dimethylhydrazine in rats are studied. It is shown that treatment with the drug failed influence body weight gain dynamics, food and...

Aging and DNA polymerase beta deficiency (beta-pol(+/-)) interact to accelerate the development of malignant lymphomas and adenocarcinoma and increase tumor bearing load in mice. Folate deficiency (FD) has been shown to induce DNA damage repaired via the base excision repair (BER) pathway. We anticipated that FD and BER deficiency would interact to accelerate aberrant crypt foci (ACF) formation...

Non steroidal anti inflammatory drugs (NSAIDs) are efficacious in chemoprevention of colorectal cancer. Therefore, the potential ability of Etoricoxib, a selective cycloxygenase-2(COX-2) inhibitor and Diclofenac, a preferential COX-2 inhibitor are considered in the chemoprevention of 1, 2-dimethylhydrazine (DMH) induced colon carcinogenesis in rat model. DMH was injected s.c. for six weeks whil...

Butyrate slows the growth of cancer cells cultured in vitro. To determine the relevance of the fermentative production of butyrate in vivo, colonic butyrate concentrations were manipulated by feeding different dietary fibres and were related to tumour development in the rat dimethylhydrazine model of large bowel cancer. It has previously been shown that guar gum and oat bran, while highly ferme...

Male Sprague-Dawley rats were given weekly s.c. injections of 1,2-dimethylhydrazine (21 mg/kg) for period of up to 20 weeks. The descending colon of treated animals killed at 2 weekly intervals was examined for morphological change, over a 30-week period, after commencement of treatment using scanning electron microscopy, light microscopy, transmission electron microscopy, and freeze-fracture t...

AIM To compare the effects of cytostatic compound dihydropyrrol derivative (D1, 5-amyno-4-(1,3-benzothyazol-2-yl)-1-(3-methoxyphenyl)-1,2-dihydro-3Н-pyrrol-3-one) and 5-fluorouracil (5-FU) on the normal colonic mucosa of tumor-bearing rats and to estimate the relationships between proliferation of normal colonic mucosa and tumor growth parameters. METHODS 1,2-dimethylhydrazine (DMH) carcinoge...