[Study of the effect of a food additive Medetopect on metabolic kinetics of transuranic radionuclides in animal body].

The effect of Medetopect, a food additive, on the metabolic kinetics of transuranics (239Pu and 241Am) has been studied experimentally in white mongrel rats following chronic intake by ingestion. The Medetopect application has been shown to be advantageous for reduction of the 239Pu and 241Am absorption from and content of the gastrointestinal tract of the animals.

[Radionuclide biokinetics as a function of the age of experimental animals].

Behaviour of radionuclides with different distribution types in the organism of animals of various ages was studied. Depending on the age of experimental animals, an essential difference in biokinetic parameters such as coefficients of absorbtion from gastro-intestinal tract, distribution and retention levels in critical organs, retention and excretion rates of radionuclides was found.

[The effect of age on the distribution of 241Am in the rat body].

In experiments with albino mongrel rats aged from 2 weeks to 1.5-2 years, the kinetics of 241Am distribution was studied after single intraperitoneal administration thereof. The content of 241Am in the skeleton was shown to decrease and in the liver to increase with age.

[Lung histopathology during plutonium-238 incorporation].

In experiments with albino mongrel female rats a study was made of the response of the lungs to a single intratracheal injection of nitrate of 238Pu (0.4-740 kBq/kg). The nature of the inflammatory disease, the lymphoid tissue condition, pneumosclerosis occurrence, and the frequency and spectrum of lung tumors were shown to be a function of dose of the radionuclide administered.

Carcinogenic effects in rat progeny exposed perinatally to radionuclides.

The distribution of two transuranic elements, plutonium and americium, in pregnant rats and in their fetuses, and the carcinogenic effects seen in progeny exposed perinatally are discussed. The appearance of malignant tumours in the liver and skeleton corresponds to the pattern of deposition of these radionuclides in the body.