[Study of the effect of a food additive Medetopect on metabolic kinetics of transuranic radionuclides in animal body]. / Izuchenie vliianiia pishchevoi dobavki "Medetopekt" na kinetiku obmena transuranovykh radionuklidov v organizme zhivotnykh.

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]. / Biokinetika radionuclidov kak funktsiia vozrasta éksperimental'nykh zhivotnykh.

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]. / Vliianie vozrasta na raspredelenie 241Am v organizme krys.

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]. / Gistopatologiia legkikh pri inkorporatsii plutoniia-238.

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.

[Absorption of 249Bk from the gastrointestinal tract of rats]. / Vsasyvanie 249Bk iz zheludochno-kishechnogo trakta krys.

In experiments with albino mongrel female rats a study was made of the absorption of 249Bk from the gastrointestinal tract after a single per os administration. The bulk of 249Bk (96 per cent) administered either intravenously or per os was mainly deposited in the skeleton and liver. The value of 249Bk absorption from the gastrointestinal tract by days 4 and 8 following administration was 0.05 per cent.

[Absorption of 241Am in the gastrointestinal tract]. / O vsasyvanii 241Am iz zheludochno-kishechnogo trakta.

In experiments with rats a study was made of a number of factors influencing the resorption of 241Am from the gastrointestinal tract (GIT). The resorption of 241Am from GIT was found to be 120-245 times more intensive in neonatal rats, during the first 21 days after birth (a milk diet), than in adult animals. A milk diet for adult rats produced a 5-fold increase in the resorption of 241Am from GIT. The additional administration of digestive enzymes, as a homogenate from pancreas and small intestine, produced a 7--9-fold increase in the rate of 241Am resorption from GIT.

[Absorption from the gastrointestinal tract of rats of biologically incorporated 241Am found in fish]. / Vsasyvanie iz zheludochno-kishechnogo trakta krys "biologicheski inkorporirovannogo" 241Am, soderzhashchego v rybe.

In experiments on mongrel albino rats it was shown that the absorption of 241Am "biologically incorporated" in fish from the gastrointestinal tract amounted to 0.1% and exceeded by 4.5 times the intake of 241Am nitrate and by 6 times the absorption of 241Am administered in fish externally contaminated with americium 241.

[Metabolic kinetics and the biological action of 238Pu in the body of rabbits after intratracheal administration]. / Kinetika obmena i biologicheskoe deistvie 238Pu v organizme krolikov pri intratrakheal'nom vvedenii.

A study was made of the distribution and biological effect of 238Pu nitrate intratracheally administered to rabbits. The skeleton and liver were the main organs in which 238Pu was secondarily deposited to make 63.5 and 12.9%, respectively, of the total amount administered. For 60 days of observation 15.3% of the amount administered were excreted in feces and urine. With 238Pu dose of 520 kBq/kg acute radiation sickness developed while at a dose of 4 kBq/kg the life span of animals did not vary from the control.

[Modification of the process of resorption of alpha-emitting nuclides from the gastrointestinal tract depending upon the properties of administered compounds and the physiological state of rats]. / Modifikatsiia protsessov rezorbtsii alpha-izluchaiushchikh nuklidov iz zheludochno-kishechnogo trakta v zavisimosti ot svoistv vvodimykh soedinenii i fiziologicheskogo sostoianiia krys.

In experiments on rats a study was made of resorption from the gastrointestinal tract of simple salts, complex compounds and "biologically incorporated" forms of transuranium nuclides, the influence of age, pregnancy and chemically active substances (for instance, trivalent iron and ethyl alcohol) on this process.

[Dynamics of changes in the rat thymus gland as affected by intratracheal administration of 238Pu]. / Dinamika izmenenii vilochkovoi zhelezy krys pri intratrakheal'nom vvedenii 238Pu.

A study was made of the effect of intratracheal administration of 238Pu nitrate on rat thymus. Incorporation of an acutely effective dose of the radionuclide (740 kBq X kg-1) induced damages to all thymus structures. The optimal blastomogenic 238Pu amount (92.5 kBq X kg-1) administered during the chronic period of the disease caused complex changes of atrophic, hyper- and neoplastic nature the lymphoid component of the thymus being primarily damaged.

[Berkelium-249 metabolism in the body of animals]. / Obmen berkliia-249 v organizme zhivotnykh.

A study was made of the kinetics of metabolism and distribution of 249Bk within the albino rat body. After the intraperitoneal administration of 249Bk nitrate, the radionuclide circulated with blood for a long time and was deposited mainly in the skeleton (up to 39.8% of the quantity administered) and liver (18.4%). The radionuclide concentrations in the adrenal glands, liver, spleen, kidneys and osseous tissue were 7.3, 3.2, 1.3, 1.1, and 1.2%, respectively, of the quantity administered per 1 g of fresh tissue. 249Bk was mainly excreted in urea. During 30 days of observation 18.2% and 10.4%, of the quantity administered, were excreted in urea and feces, respectively.

[Kinetics of americium metabolism in prolonged body uptake in rats]. / Kinetika obmena ameritsiia pri dlitel'nom postuplenii v organizm krysy.

A study was made of the kinetics of 241Am metabolism in a rat body during long-term parenteral administration thereof. It was shown that americium 241 was deposited mainly in the skeleton and liver (47% and 51%, respectively, of the total amount accumulated in the organism) and excreted in feces.

[The blastomogenic effect of 249Bk in rats]. / Blastomogennyi éffekt 249Bk u krys.

It is shown that 249Bk nitrate injected intraperitoneally in a wide range of doses to albino mongrel female rats is preferentially accumulated in the bony tissue (39.8%) and liver (18.4%). Incorporation of 249Bk to rats results in development of osteosarcomas, neoplasms of hemopoietic and lymphoid tissues, mammary tumours, thyroid and pituitary glands.

[Recovery processes in damage to rats by 252Cf]. / Vosstanovitel'nye protsessy pri porazhenii krys 252Cf.

The types of recovery processes were demonstrated in experiments on albino rats damaged with 252Cf. The frequency and the degree of manifestation of both pathological and recovery processes were function of radiation dose and time of its formation. The results obtained indicate that changes induced by the incorporation of 252Cf, within a wide range of doses, are compensated incompletely to be manifested later by sklerotic, hyperplastic and neoplastic processes.