Biomedical subjects
Publications and source records attributed to H R Scherf.
Animal experiments on markers of tumors induced by physical and chemical carcinogens are discussed. The results lead to the conclusion that there are no specific markers induced by certain carcinogenic agents.
Fourteen snakes of the species Python reticulatus were randomized after one year's adaptation in our laboratory, i.e., at the age of 18 months. Groups of three animals (average body weight, 1 kg) were subjected to lifelong administration of 24, 12 or 6 mg/kg body weight of N-nitrosodiethylamine (NDEA) at fortnightly intervals. The NDEA-containing aqueous solution (0.3 ml/kg body weight) was administered by gavage. Five untreated animals served as controls. Snakes receiving 24 mg/kg NDEA died from toxic liver and kidney damage within the first year of experimentation. The three snakes receiving 12 mg/kg NDEA died within the last three months of the second year of treatment. These animals had developed multiple benign and malignant tumours in the liver and the kidney. The two animals that died last also developed tumours in the oral cavity and the trachea. Animals treated with 6 mg/kg NDEA died from tumours in the trachea.
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The carcinogenic substance 4-dimethylaminoazobenzene and the non-carcinogen azobenzene were administered orally once a day to male Sprague-Dawley rats over several weeks at an equimolar dosage of 5-10(-5) moles/kg. Their immunological properties were examined in four different tests. The two substances suppress the cellular immune reactions of the rats already during the first month of treatment. The degree of efficiency of the immunosuppressive property decrease with the degree of antigenicity of the test antigen. Even a two-month treatment of the animals with the two substances had no evident influence on antibody formation. Correlations between the immune response and the carcinogenic effect were not demonstrable.
In a chronical test guppies were incubated in the darkness in diethylnitrosamine-concentrations of 26 and 100 mg/1 up to seven months. This treatment led, because of the toxicity of the compound, to lesions in organs of the peritoneal cavity. Tumors were not observed. The cause of the lack of carcinogenic activity is discussed.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
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