Nozomi Takemura

Induction of bladder cancer in mice by implanting pellets containing tryptophan pyrolysis products.

A high incidence of transitional cell carcinomas were induced in the bladder of mice by bladder implantation of pellets containing crude tryptophan pyrolysate and the pyrolysis products, 3-amino-1,4-dimethyl-5H-pyrido-[4,3-b]indole (Trp-P-1) and 3-amino-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), which are highly mutagenic substances.

Mutagenic activity of N-nitrosomethamphetamine and N-nitrosoephedrine

The mutagenicity of N-nitrosomethamphetamine (NMA) and N-nitrosoephedrine (NEP), which were synthesized in our laboratory, was examined by the modified pre-incubation method of Ames assay using Salmonella typhimurium TA100 and TA98. Both nitroso compounds showed significant mutagenic activity in the presence of hamster S9.

MECHANISM OF INDUCTION OF THE INDUSTRIAL BLADDER CANCER

Since the discovery of industrial bladder cancer by Rehn in 1895, many incidences of the occupational bladder cancer have been reported with the progress of dyestuff industry. On the other hand, various industrial bladder carcinogens have been found in aromatic amines of dyestuff intermediates experimentally and epidemiologically. The biochemical mechanisms that the metabolites of the parent aromatic amines have more potent carcinogenic action than the parent chemicals have been found. From these findings, some chemicals being slightly changed in their chemical structure were produced and it was found that these chemicals were usefull for dyestuff intermediates as well as quite safe for cancer induction. It is very necessary for the prevention that new aromatic amines should be checked in order to know whether they are carcinogenic or not. From this point of view, 5-aminoacenaphtene and 5-nitroacenaphthene, the intermediates of fluorescent whitening agents, were examined by the author, and it was proved experimentally that these new aromaiic amines have carcinogenic action to mice.