[Selective accumulation of 131I-labeled IKO-1 monoclonal antibodies in the tissues of mouse L 1210 lymphoid leukemia]. / Izbiratel'noe nakoplenie mechennykh 131I monoklonal'nykh antitel IKO-1 v tkani myshinogo limfoleikoza L 1210.

Monoclonal antibodies (MCA) ICO-1 of IgG3 isotype against 1a-like human antigens were labelled with 131I using chloramine T; a radionuclide-bound fraction was isolated by radiochromatography. Basing on the results of assessment of complement-dependent cytotoxicity against lymphocytes from the lymph nodes of BDF1 mice a conclusion was made that MCA immunological reactivity changed slightly after radionuclide tracer administration. In vitro experiments with a panel of normal and malignant cells showed 131I-MCA binding with cells of mouse lymphoid leukemia L1210 and hemocytoblastosis La as well as with spleen and lymph node normal lymphocytes. During in vivo experiments 131I anti-la MCA at a dose of 30 micrograms (specific activity of 32.10(10) Bq/mmol) was administered intravenously to BDF1 mice with transplantable lymphoid leukemia L1210. Radiometry of the organs 24 h after administration of antibodies showed their accumulation in a solid tumor localized on intestinum tenue mesenteriale. The ratio of concentrations of labelled antibodies (in % of the administered amount per 1 g) of tumor/blood was 2.4, that of tumor/liver--4.5. For normal nonimmune 125I-IgG this rate was 0.4 and 0.7, respectively. A high level of MCA in the blood is a factor decreasing MCA diagnostic potentialities. The use of F(a, b)-fragments may considerably decrease the role of this factor. The data obtained suggest a possibility of the use of MCA ICO-1 for in vivo radioimmunoassays of some hematological tumors.

[Dosimetric characteristics of internal irradiation with radioactive nuclides of iodine]. / Dozimetricheskie kharakteristiki vnutrennego oblucheniia radioaktivnymi nuklidami ioda.

The paper is concerned with some data on mean absorbed dose values in the animals' organs, the time course of their formation and the character of microdistribution of an absorbed dose around thyroid follicles in internal irradiation of the rat body with 131I and 125I. A raised level of irradiation of the animals' pituitary body is noted. The authors provide dosimetric characteristics of irradiation of thyroid microstructures noting that 125I creates more inhomogeneous distribution of an absorbed dose around thyroid follicles compared to 131I, irradiating, to a greater extent, the follicular membrane and, to a lesser degree, the nuclei of surrounding cells whereas 131I provides homogeneous irradiation of thyroid cells. The authors give a comparative critical analysis of the quantitative and microdosimetric characteristics and literature data.

[Comparative biological effectiveness of 125I and 131I]. / Sravnitel'naia biologicheskaia éffektivnost' 125I i 131I.

An experimental study of comparative biological efficacy of 125I and 131I at equal absorbed doses (2.3 and 13 Gy) in the thyroid of rats showed that the blastomogenic effect of both radionuclides was almost the same. Sex differences were found in the development of long-term consequences (20 mos. after drug administration): breast tumors developed in female rats and thyroid tumors in male rats.

[Disorders of immunologic homeostasis as affected by radioactive iodine preparations]. / Narusheniia immunologicheskogo gomeostaza pod deistviem preparatov radioaktivnogo ioda.

(CBA X C57B1/6)F1 mice were injected with 125I and 131I-sodium iodide at a dose of 5.74 X 10(4) Bq/g. For a long time after such treatment the animals manifested an increased level of spleen cells humoral immune response to a foreign antigen (sheep erythrocytes), the autoreactivity of spleen and lymph node lymphocytes to autologous erythrocytes was also elevated. At the same time the selective migration of 51Cr-labeled spleen lymphocytes to the peripheral lymphoid organs was suppressed. The use of a model system of adoptive cell transfer revealed an increase in the functional activity of cells suppressing a humoral response in mice treated with radiopharmaceuticals. The most pronounced disturbances of immunological reactivity in mice took place 6 mos. after the beginning of the experiment. The results obtained indicated that mechanisms of immune response regulation played a certain role in disturbances of immunological homeostasis induced by radioactive iodine agents.

[Functional activity of cells suppressing the humoral immune response in internal irradiation]. / Funktsional'naia aktivnost' kletok-supressorov gumoral'nogo immunnogo otveta pri vnutrennem obluchenii.

In the adoptive transfer system of (CBA X C57BL/6)F1 mice, the estimation was made of the function of splenic cells, suppressors of the humoral immune response to sheep erythrocytes 1 and 6 months following the injection of 125I and 131I. Low absorbed doses of the radioactive isotopes were shown to stimulate the activity of the suppressors generated in mouse spleen.

[Accumulation of 125J-triiodothyronine in the transplanted tumors of mice and rats]. / Nakoplenie 125J-triiodtironina v perevivnykh opukholiakh myshei i krys.

Investigations carried out in various transplantable tumours (Lewis carcinoma, carcinoma-37, melanoma B-16 in mice and sarcoma-45 in rats) did not show 125J-triiodothyronine accumulation by the tumour.

[Distribution kinetics and metabolism of triiodothyronine and thyroxine in the organs and tissues of mice with transplanted Lewis carcinoma]. / Osobennosti raspredeleniia i kinetiki obmena triiodtironina i tiroksina v organakh i tkaniakh myshei s perevivnoi kartsinomoi L'iuis.

A comparative analysis of triiodothyronine (T3) and thyroxine (T4) distribution in organs and tissues of tumour-bearing and intact mice conducted wih 125J labelled T3 and T4 has shown considerable differences in the accumulation character of these hormones in mice with Lewis carcinoma and in intact animals in the liver, kidneys, lungs, adrenal glands, lymphatic nodes. Low T3 and T4 concentration in the blood of tumour-bearing mice was observed during the whole period of study.

[Enhancement of the biological effectiveness of low-energy quantum radiation. Microdosimetric basis for a selective radiation effect on chromosome material in cells]. / Povyshenie biologicheskoi éffektivnosti nizkoénergetichnogo kvantovogo izlucheniia. Mikrodozimetricheskoe obosnovanie izbiratel'nogo radiatsionnogo vozdeistviia na khromosomnyi material kletok.

Microdosimetric data are presented indicating the possibility of a selective action of ionizing radiation on the chromosomal material of cells using low-energy electrons and photoelectrons formed, as the result of the photoeffect, on the incorporated or native atoms inside DNA upon irradiation with low-energy quantum radiation ("X-activating" effect). A presumed biological effectiveness of the "X-activating" effect on B-16 melanocarcinoma, with bromine and iodine incorporated into the DNA molecule, was estimated.

[Lymphocyte migration in internally irradiated animals. Effect of internal gamma radiation on the migration properties of spleen lymphocytes labeled with 51Cr]. / Migratsiia limfotsitov v organizme v usloviiakh vnutrennego oblucheniia. Vliianie vnutrennego gamma-oblucheniia na migratsionnye svoistva mechennykh 51Cr limfotsitov selezenki.

In experiments on CBA mice it was shown that migration of 51Cr-labeled spleen lymphocytes, injected intravenously, to lymph nodes of intact recipients was suppressed 6-24 months after the administration of a radiopharmaceutic preparation of selenium-75-selenomethionine in a quantity forming the doses of 1 Gy and 1.5 Gy absorbed within the whole body and lymphoid organs, respectively. Migration of labeled lymphocytes to the liver, kidneys and lungs, as well as their retention in the circulating blood, were increased. As the result of the migration disorders the specific affinity of lymphocytes for peripheral lymphoid tissue decreased.

[Lymphocyte migration in internally irradiated animals. Effect of internal beta radiation on the migration of spleen lymphocytes in CBA mice]. / Migratsiia limfotsitov v organizme v usloviiakh vnutrennego oblucheniia. Vliianie vnutrennego beta-izlucheniia na migratsiiu limfotsitov selezenki myshei CBA.

The syngeneic transfer system was used to study migration of 51Cr-labelled spleen lymphocytes in mice after incorporation of beta-emitter, 35S-methionine. Migration of 51Cr-labelled lymphocytes to lymph nodes was stably decreased, and to liver, kidneys and lungs increased. The lymphocyte migration impairment was associated with the influence of beta-radiation on both the migratory properties of cells and the factors of their microenvironment responsible for the lymphocyte migration within the mouse body. No distinctions were observed in the character and manifestation of disturbances of the lymphocyte migration after the injection of 35S-methionine and gamma-emitter, 75Se-selenomethionine.

[Universal isoenergetic and dose functions of a point source]. / Universal'nye izoénergeticheskaia i dozovaia funktsii tochechnogo istochnika.

The authors describe in an analytical form isoenergy and dose functions of a point isotropic source of monoenergy electrons that can be applied to any initial energy electrons within the range of 0.5-10 MeV in a homogenous isotropic model of internal irradiation (aqueous medium). The above functions have a simple form that makes it possible to easily calculate dose exposure of tissue microstructures in internal irradiation with Coster-Crohnig, Auger and internal conversion electrons and photo-electrons for a wide range of problems in nuclear medicine and radiobiology.

[Lymphocyte migration in the body in conditions of internal irradiation. 2. Disorders of lymphocyte microenvironmental factors in organs]. / Migratsiia limfotsitov v organizme v usloviiakh vnutrennego oblucheniia. Soobshchenie 2. Narushenie faktorov mikrookruzheniia limfotsitov v organakh.

At later times after the injection of selenium-75-selenium methionine to CBA mice the inhibition of migration of intravenously injected normal 51Cr lymphocytes to the lymph nodes and liver lasted for a long time. On the contrary, no changes in the normal lymphocyte migration within the animal body were observed after total-body gamma-irradiation with the dose of 4 Gy. The data obtained are indicative of the radiation-induced disturbance of the microenvironment factors, which provide migration of lymphocytes within the body, during the long-term exposure to radiation emitted by the incorporated source.