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Biomedical subjects

B Mu

Publications and source records attributed to B Mu.

6 recordsLinked to original sources
PubMed1987

Retinyl acetate effects on the life span and the incidence of cryptogenic neoplasms in C3H mice.

The effect of feeding 0.02% retinyl acetate on the development of cryptogenic neoplasms and the life span of C3H/HeJ (+) mice of both sexes was studied. The survival at 105 weeks was 58% in untreated males and 28% in untreated females vs. 39% in treated males and 14% in treated females. The average weight in treated groups was also 10-15% lower. The incidence (percent) of neoplasm-bearing animals and total neoplasms was 87% and 57, respectively, in female controls vs. 93% and 55 in treated females. In male controls, these values were 57% and 39 compared with 50% and 38 in treated males. In treated animals, there was no reduction in the most common neoplasms, that is, neoplasms of the mammary gland and liver. The numbers of ovarian neoplasms and lung adenomas were slightly lower. Therefore, retinyl acetate exerted, at best, only a slight inhibitory effect on development of some types of cryptogenic neoplasms in mice.

Animals↗
PubMed1985

Evaluation of the effects of cotinine and nicotine-N'-oxides on the development of tumors in rats initiated with N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide.

The effects of cotinine and nicotine-N'-oxides on tumor development in F344 rats initiated with N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide [(FANFT) CAS: 24554-26-5] were evaluated. When rats were 6 weeks old, FANFT in an agar diet was administered for a 6-week period. Subsequently, cotinine, trans-nicotine-N'-oxide, and a mixture of cis-nicotine-N'-oxide and trans-nicotine-N'-oxide in drinking water were given as promoters in concentrations of 0.1, 0.02, and 0.02%, respectively. These nicotine metabolites were offered ad libitum for 78 weeks. Control groups consisted of rats that received tap water with or without prior administration of FANFT. Cotinine, trans-nicotine-N'-oxide, and the mixture of cis- and trans-nicotine-N'-oxides were neither carcinogens nor promoters of urinary bladder tumors in rats initiated with FANFT. A reduced incidence of urinary bladder tumors was observed in FANFT-pretreated animals that also received a mixture of cis- and trans-nicotine-N'-oxides. FANFT administration increased the incidences of mesothelioma of the peritoneum and thyroid tumors. Tumor formation in the tongue and palate observed in FANFT-treated rats was not affected by administration of these nicotine metabolites. There was, however, a significant increase in the incidence of forestomach tumors in rats that were initiated with FANFT and subsequently received either trans-nicotine-N'-oxide or a mixture of cis- and trans-nicotine-N'-oxides.

Animals↗
PubMed1985

The effects of catechol on the urinary bladder of rats treated with N-butyl-N-(4-hydroxybutyl)nitrosamine.

The effect of catechol on the development of urinary bladder tumors in Fischer rats treated with N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) was studied. A solution of 0.05% catechol and 0.001% BBN was administered in the drinking water ad libitum for 78 weeks. The urinary bladders were then removed and examined microscopically. No statistically significant difference was observed between the experimental group receiving 0.001% BBN with 0.05% catechol and animals receiving 0.001% BBN alone with respect to the incidence of hyperplasia, papilloma, or carcinoma of the urinary bladder. Animals receiving 0.05% catechol alone in the drinking water had no macroscopic or microscopic lesions significantly different from those in control animals receiving tap water. Analyses of the urine of animals receiving catechol in their drinking water indicated that greater than 99% of the catechol present was in the form of either glucuronide or sulfate conjugates. In a second bioassay, the potential cocarcinogenicity of catechol, administered together with BBN, was explored by direct instillation into the urinary bladder. The development of calculi and possible infections of the urinary tract within all groups of treated animals suggests that this bioassay technique for cocarcinogenicity is of questionable value. These data show that catechol at the dose and mode of administration employed in this study did not affect the epithelium of the urinary bladder or enhance the carcinogenic activity of BBN.

Animals↗
PubMed1984

Chemically induced rat odontomas: morphogenetic considerations.

Three complex odontomas were found in 30 castrated male rats injected with N-methyl-nitrosourea (MNU) and fed a high-fat diet. Histological studies were performed and the related literature was reviewed. The morphogenesis of the tumors is discussed in the light of the bibliographic data and personal findings.

Animals↗