[Effect of radio-ecological conditions in the ChNPP exclusion zone on morphofunctional state and responsiveness of organs and tissues of laboratory animals].

The state of hematopoietic, reproductive and endocrine systems of the organisms of male rats and their offspring in generations (F0-F1-F2) was studied, and the sensitivity of an organism to the action of carcinogen (Af mice) after a stay in the ChNPP exclusion zone was analyzed. It was ascertained that the most significant changes of the morphofunctional state of the animals were observed in the II generation (F2), which remained for a long period under the conditions of radioactive contamination. We have revealed an increased number of leukocytes, neutrophils, lymphocytes, and, especially, monocytes as against while the decrease in the number of erythrocytes and haemoglobin content; the decrease of thyroid function and cortical layer of the adrenals as opposed to while the increase in the relative weight of testes and their epididymides and the decrease in the number of spermatocytes and spermatozoa in the testis tissue. The exposure of Af mice in the exclusion zone increases the processes of mutagenesis and carcinogenesis, and changes the organism response to standardized action of chemical carcinogen. The increase in the exposure time of animals intensifies metabolic processes in a cell and increases their sensitivity to the action of xenobiotics.

[The influence of ecological factors of Polesky State Radioecological Reserve on spontaneous and chemically induced mutagenesis and tumor formation].

The cycle of researches of the influence of an exposion of mice of line Af in the conditions of the zone of Chernobyl disaster on spontaneous and chemically induced mutability, lung tumour (adenomas), morphological and functional condition of alveolar macrophages, and also genetic effects in natural populations wild rodents is executed. The increase in polychromatic frequency in mouse bone marrow, adenomas in lungs, and change of sensitivity of an organism to action mutagen and transgenerational transfer of genetic damages is shown.

[Study of gustatory sensitivity to phenylthiocarbamide in thyroid diseases].

The aim of the study was to reveal a relationship between gustatory sensitivity to phenylthiocarbamide (PTC) and thyroid disease. The distribution of PTC sensitivity was studied in 198 healthy individuals, 100 patients with autoimmune thyroiditis (AIT), 139 patients with nodular euthyroid goiter, and 100 patients operated on for thyroid cancer. There was a statistically significant decrease in the number of PTC-resistant male and females patients in the thyroid cancer group and an increase in the proportion of PTC-resistant male patients in the AIT and nodular euthyroid goiter groups.

[Iodine metabolism and pathologic processes in the thyroid gland under radioiodine lesions in the regions of goitrous endemia].

An existing discrepancy between the prognostic estimations and real thyroid gland sickness rate due to radiation exposure from Chernobyl is an evidence of inaccuracy of radiation doses determination. The estimation of the thyroid cancer risks is based on the assumption that the absorbed dose is uniformly distributed in the organ. But functional asynchronicity specific for iodine metabolism in thyroid may modify a space distribution of the dose. The biochemical features of the contaminated areas including iodine deficit and goitrous endemia usually are not taken into account may influence the second phase of thyroid carcinogenesis that is the promotion due to increased accumulation of some carcinogenic microelements in goitrous thyroid. In the work we consider these problems which can make significant changes in radiation risks estimation.

[Dose-effect and time-effect characteristics in process of tumorigenesis under combined action of ionizing radiation and chemical carcinogen]. / Zavisimosti doza-éffekt i vremia-éffekt v protsesse opukholeobrazovaniia pri sochetannom deistvii ioniziruiushchego izlucheniia i khimicheskogo kantserogena.

Studying of dose and time dependences of frequency of adenomas appearing under the combined effect of radiation and urethane ingressed during different terms after irradiation has show that the frequency of tumours is determined both by radiation dose, and the time interval between irradiation and ingressing of cancerogenic substance. The data obtained show the period of preservation of the induced damages and non-linearity of the process of tumour-formation under the combined effect of radiation and toxic factors on the organism. The latter is necessary to be taken into account when forecasting the radiation risk under the real ecological conditions.

[Combined effect of gamma-irradiation and sodium nitrite on the oxidative sensitivity of rat hemoglobin]. / Vliianie sochetannogo deistviia gamma-izlucheniia i nitrita natriia na oksilitel'nuiu chuvstvitel'nost' gemolobina krys.

gamma-Irradiation has been defined to increase in the rats blood the methemoglobin level providing for shortening the initiation phase and accelerates the autocatalytic phase initiation, reduces the period of half transforming hemoglobin into methemoglobin and increases the velocity of its oxidation. Alongside with the latter there is observed a violation of methemoglobin concentration growth dependence on the animals irradiation dose (in the range of 0.16-0.50 Gr). The hemoglobin oxygenation reaction kinetics with the initial level of hemoglobin unexceeding 3% has been determined as having a biexponential character. The reaction kinetics parameters don't depend on ionizing radiation and number of sodium nitrite oxidized subunits formed in the process of reaction in the case if their composition unexceeds 50% of the total level.

[Contents of plutonium and microelements in the hair of Belarus inhabitants living in the areas contaminated during the Chernobyl AES accident]. / Soderzhanie plutoniia i nekotorykh mikroélementov v volosakh zhitelei Belarusi, prozhivaiushchikh na territorii, postradavshei pri avarii na Chernobyl'skoi AES.

The levels of plutonium were studied in the body of inhabitants of the Minsk and Gomel Regions. Their hair was used as the indicator of its levels. The hair concentrations of plutonium correlated with its content in the ribs. The hair levels of lead in the inhabitants of some populated localities of the Gomel Region were found to be higher than those in the residents of unpolluted areas and industrial centers of the Republic of Belarus.

[Role of ecological factors in the pathogenesis of thyroid cancer in regions of Byelarus exposed during the Chernobyl AES accident]. / Rol' ékologicheskikh faktorov v patogeneze raka shchitovidnoi zhelezy v regionakh Belarusi, postradavshikh pri avarii na Chernobyl'skoi AES.

The results of the increased functional asynchronism of the follicular structures of the thyroid gland in the endemic with respect to goitre regions at the intrathyroid distribution of radioactive iodine have been analysed. The unevenness of inclusion of radioiodine into the gland locus, which concentrate iodine, and the formation of higher dose effects in the microparts of the thyroid tissue altered by goitre, then the averaged values of irradiation of the whole gland inherent in the evaluation of risk of the thyroid carcinogenesis, has been shown. It is substantiated, that the increased deposit of some radionuclides and toxic microelements in the gland, altered by goitre, is the possible mechanism of promotion in the demonstration of the earlier initiated damaged genomes of follicular cells.

[The effect of dosage strength on the induction of chromosome aberrations and lung tumors in mice under the combined action of ionizing radiation and chemical substances]. / Vliianie moshchnosti dozy na induktsiiu khromosomnykh aberratsii i opukholei legkikh u myshei pri sochetannom deistvii ioniziruiushchego izlucheniia i khimicheskikh veshchestv.

In the experiment with combined influence of single or prolonged gamma irradiation (35 cGy) and chemical agents (urethanum, nitrogen oxide) on the induction of chromosome aberrations in bone marrow cells and lung tumor the effect of dose rate was studied. The frequency of chromosome aberrations increased with dose rate. Yet the correlation between the ratio of irreparable (stable) aberrations and dose rate was of inverse direction. The character of variations in lung adenoma frequency under multifactor influence in the case of prolonged irradiation (increase with dose rate decrease) supports the correlation between the level of stable aberrations in the pool of genetic lesions and the frequency of lung adenoma.

[Pulmonary macrophages during combined exposure to ionizing radiation and nitrogen oxides]. / Makrofagi legkikh pri sochetannom vozdeistvii ioniziruiushchego izlucheniia i oksidov azota.

The dynamics of cellular population of mice alveolar macrophages has been studied under separate and combined effects of ionizing radiation and nitrogen oxides. It has been shown that the combined effect exceeds significantly the sum of separate effects of the above factors with equal dose and concentration levels.

[Chromosome aberration induction in murine spermatocytes in joint exposure to radiation and sodium nitrite and nitrate]. / Indutsirovanie khromosomnykh aberratsii v spermatotsitakh myshei pri sochetannom vozdeistvii radiatsii i nitrita, nitrata natriia.

In studying the combined effect of single and fractionated exposure to gamma/neutron radiation (12.5-50 cGy) and sodium nitrite (100 mg/kg) and chronic irradiation with a mixture of radiation (25 cGy) and sodium nitrite, nitrate (10-100 mg/l) the synergistic effect was observed in inducing reciprocal translocations in mouse spermatocytes. The dose-response function of the reciprocal translocations occurrence in Af mouse spermatocytes was nonlinear; there was a "plateau" within the dose range from 25 to 50 cGy.

[The effect of ionizing radiation on nitrosamine formation from anthropogenic precursors]. / Vliianie ioniziruiushchego izlucheniia na obrazovanie nitrozoaminov iz antropogennykh predshestvennikov.

The kinetics of formation of nitrosoamines from precursors under the effect of ionizing radiation has first been quantitatively estimated, and the optimal conditions of their formation determined. The possibility of formation of nitrosoamines under the effect of low-level radiation has been investigated. Using the mathematical functions obtained from the experiments, the number of nitrosoamines, that may form under the effect of radiation in the aqueous medium, has been determined.

[The reaction of free cellular elements of the lungs to gamma exposure]. / Reaktsiia svobodnykh kletochnykh élementov legkikh na gamma-vozdeistvie.

A quantitative composition of free cell elements and morphology and mitotic activity of macrophages were studied after gamma irradiation with doses of 25.8, 77.4, and 180.6 mC/kg. Morphological changes in the lungs and a deviation from the control values of an overall content of cell elements in washings were found to be a function of radiation dose. The discrepancy between the results obtained by other authors are attributed to a limited elimination of macrophages due to pulmonary edema and restoration of the number of macrophages due to a relatively moderate mitotic activity of these cells.

[Dynamics of nitrite metabolism in the blood of irradiated rats]. / Dinamika nitritnogo obmena v krovi obluchennykh krys.

Studies of sodium nitrite metabolism and correlation between NaNO2 metabolism and methemoglobin formation in the blood of rats exposed to radiation have been carried out. It has been shown that, along with radiation-induced damage of OHb----MHb dynamic system, an increase in NaNO2 uptake rate by the blood is the factor causing intensification of methemoglobin formation in irradiated animals.

[Dynamics of methemoglobin nitrite formation in whole-body gamma irradiation of rats]. / Dinamika nitritnogo metgemoglobinoobrazovaniia pri obshchem gamma-obluchenii krys.

Methemoglobin formation was studied in irradiated and intact rats treated with sodium nitrite (7 mg/100 g bw). During combined exposure to two factors (sodium nitrite and irradiation), the biological effect assessed according to blood methemoglobin concentration exceeded the expected value derived upon summation of separate exposures, i.e. the effect appeared to be greater than the additive one.

[Content and distribution of iodine, chlorine and bromine in normal and pathologically changed thyroid gland tissue]. / Soderzhanie i raspredelenie ioda, khlora i broma v normal'noi i patologicheski izmenennoi tkani shchitovidnoi zhelezy.

The neutron-activation method was used to study the content and distribution of iodine, chlorine and bromine in 53 thyroid glands removed from patients during operation and 8 thyroid glands from persons who died in accidents. It has been shown that a statistically significant decrease in the iodine concentration occurs in struma maligna, Hashimoto's disease and a mixed form of endemic euthyroid goiter. The chlorine content did not change. The bromine concentration in all form of thyroid pathology was raised. The highest bromine content was found in "cold" forms--struma maligna, and it exceeded almost by 50 times the rates in the control group. Autoradiographic studies made it possible to establish some peculiarities in the distribution of radioactive and stable iodine in the thyroid tissue depending on its morphofunctional condition. Radioactive iodine gradients in the normal tissue did not exceed 7, in mixed (parenchymatous) forms of the goiter 42.5. The distribution of stable iodine is characterized by a high irregularity. The aplastic forms of struma maligna least of all accumulate and contain stable iodine, their structure being characterized by functional monotony.

Effect of uranium on the induction and course of experimental autoimmune orchitis and thyroiditis.

The influence of acute and chronic uranium poisoning on the induction and course of experimental autoimmune thyroiditis and orchitis was studied. It has been demonstrated that the testes and thyroid gland are involved in the general pathological process in uranium poisoning. Autoantibodies to the testes and to the thyroid gland were found to circulate in the blood of the poisoned animals. Uranium poisoning caused destructive changes in the testes and in the thyroid, similar to the picture of an autoimmune process. No summation of the effect was observed in the synthesis of autoantibodies during the induction of experimental autoimmune thyroiditis and orchitis on the background of chronic uranium poisoning although the most conspicuous histological changes were found in these groups and were characteristic of a pronounced autoimmune process.

[Iodine metabolism in uranium poisoning according to whole-body radiometry and activation analysis]. / Obmen ioda pri uranovom otravlenii po dannym radiometrii tela i aktivatsionnogo analiza

Experiments on rats showed that in chronic uranium poisoning the value of the intrathyroid iodine pool changed and time-dependent radioiodine recirculation relationship between the thyroid and the organism was upset. The process of the thyroid adaptation is a complex one, viz. the hormonal capacity of the organism being kept up through an increase in the mass of the thyroid as well as by a higher rate of iodine exchange.

[Iodine metabolism in the thyroid gland in chronic uranium poisoning]. / Obmen ioda v shchitovidnoi zheleze pri khronicheskoi uranovoi intosikatsii

The exchange of radioactive and stable iodine was studied for 21 days after the I131 injection in the thyroid gland and the blood of rats against the background of chronic uranium intoxication. The latter was accompanied by a decrease in the number of iodine-transport loci of the gland, as well as of the value of the intrathyroid iodine pool and of the stable iodine concentration in the thyroid tissue. The compensatory reaction of the thyroid gland was expressed in the increase of its mass and the rate of the thyroid metabolism as well.