Carcinogenicity of di(N-nitroso)-perhydropyrimidine (DNPP) after intraperitoneal application to rats.

Male Sprague-Dawley rats received 30 mg/kg body wt. (group I) or 15 mg/kg (group II) di(N-nitroso)-perhydropyrimidine (DNPP) by the intraperitoneal route once a week for life. The DNPP treatment significantly reduced the life expectancy in both groups. DNPP induced tumors of the esophagus (27% incidence in group I, 33% in group II) and possibly also of the liver (4% incidence in group I, 8% in group II).

Limitations of in vitro short-term tests as prescreening models for carcinogenicity in industry: a theoretical approach.

The validity of in vitro short-term tests was investigated using published data from 10 investigations on a total of more than 800 compounds. The predictive value strongly depends on the number of carcinogens investigated in a test and, therefore, is not suited to describe the reliability of a short-term test. The usefulness of short-term tests as prescreening models for possible carcinogenicity to be used as a routine procedure in industry is very limited. If it is assumed that most of the compounds tested are non-carcinogenic, other criteria than results of short-term tests should be used additionally in deciding which compounds require investigation in long-term bioassays for possible tumorigenic hazards.

Effect of disulfiram on acetoxymethyl-methyl-nitrosamine-induced tumors in rats.

Male Sprague-Dawley rats were given 10 weekly intravenous injections of acetoxymethyl-methylnitrosamine (AMMN = N-nitroso-acetoxymethyl-methylamine). One group was also treated with disulfiram (DSF) by gavage twice daily five times per week. DSF markedly reduced the rate of heart and lung tumors but not of tumors at other organ sites. In animals treated with the combination of DSF and AMMN a significant incidence of neurogenic tumors was observed. No neurogenic neoplasms occurred in animals treated with AMMN alone. During the observation period DSF showed no carcinogenic potential.