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It was shown that the dependence of the micronucleus number and chromosome aberration on irradiation dose is linear quadratic, the values of linear coefficient being different. The distribution of ameliorators and children from the areas with higher irradiation level by micronucleus test conforms to Poisson distribution, while the distribution by chromosomal analysis approaches to binomial distribution.

The cytogenetic disturbances in peripheral blood lymphocytes from patients with various thyroid diseases were studied. It was found that hormone administration results in chromosome aberration and micronucleus (MN) rate increase. The changes in the chromosome aberration spectrum correspond with radiation induced changes in the spectrum. The additional irradiation of cells in vitro caused the lower level of MN in patients treated with hormones than in control donors group.

The effect of MDI, the agent of plant origin, on the cell cycle and the number of micronuclei in human lymphocytes after gamma-irradiation has been studied. It has been found that the treatment of lymphocytes with MDI stimulates DNA synthesis and reduces the delay of irradiated cells in (G2 + M) phase. Moreover post-irradiation cell treatment with MDI reduces the number of damaged cells.

A unique installation and an original investigation method are described for studying mechanoluminescence of lymphocytes. The spectral content of mechanoluminescence of lymphocytes of human peripheral blood showed maxima of optical emission at 262, 291, 335 and 412 nm. Intraperitoneal administration of hydrocortisone in mice enhances thymocyte mechanoluminescence intensity after 2 and 3 days by 33 and 62%, resp. It is shown that Acridine orange, reacting with murine thymocytes and their nucleoids, affects intensity of their mechanoluminescence, depending on the value of concentration of the injected intercalator.

Current information is presented in the paper concerning the biological indication of radiation effects within a wide range of doses. The radiobiological phenomena that lay the basis for the development of methods of diagnosis of radiation injury are discussed. Basic requirements to biological indicators and principles of elaboration of the system of laboratory diagnosis of radiation injury are reported. A new classification of biological indicators of radiation affection based on the principles of pathogenesis is proposed. The informativeness of the diagnosis methods available is evaluated and the directions, which the search for new biological indications of radiation effect should follow, are outlined.

Comparative analysis of biochemical indices that reflect the proteolysis rate in rat peripheral blood lymphocytes in normal conditions and during the first 4-6 h after whole-body single uniform gamma-irradiation with lethal (7.5 Gy) and nonlethal (3 Gy) doses has revealed that the pronounced activation of proteolysis in lymphocytes and the disturbances in the inhibitor/protease balance are characteristic of the severe form of radiation damage with fatal outcome. Simultaneously changes occur in biochemical indices of plasma that reflect a catabolic pathway of metabolism in the whole-body. The absence of similar changes in the blood of the survived animals permits to recommend the biochemical indices under study to be used for early prognosis of the radiation affection outcome.

Comparative studies of acridine orange (AO) and ethidium bromide interactions with supercoiled DNA (scDNA) of thymocytes were performed in which various conformational changes were induced. AO may be efficiently used for evaluation of conformational alterations of scDNA. Moreover, employing the maximum values of AO fluorescence allows to determine the maximum levels of scDNA relaxation.

Fluorescent analysis of structural changes of nucleotide in the blood associated with AT fragments has been studied in rats, gamma-irradiated with doses of 2 and 4 Gy. It was demonstrated that the haematological, gerontological and cancerogenic late consequences were preceded by the structural genomic disturbances determined by 30 day after irradiation.

The share of lymphocytes with abnormal nuclei in the peripheral rat blood was found to increase during the first 24 h following irradiation with doses LD0, LD50, and LD100. With LD50 the index under study significantly varied in survived, died and control animals. It is suggested that the occurrence of abnormal nuclei in the peripheral rat blood is the result of the two processes, namely, the mitotic division and apoptotic death of cells.

The micronuclei of PHA-stimulated human lymphocytes were assayed by comparison of electron microscopy and light microscopy data. The length of the cell cycle was checked by the flow cytofluorimetry method. Both the variability of the apoptosis stages and the increase in (G2+M) period in gamma-irradiated cultures were found. It is concluded that at least part of the micronuclei results from the cell nucleus "partition" during the apoptosis type cell death.

A study was made of the action of novobiocin on degradation and repair events in supercoiled nuclear DNA from three thymocyte fractions obtained by ficoll-paque gradient sedimentation. When added before gamma-irradiation novobiocin (1.9 mg/ml) exerted a radioprotective effect during the "second wave" of supercoiled DNA degradation. It is suggested that this effect may be due to the inhibition of DNA topoisomerase II.

A study was made of the radioprotective and therapeutic effect of potassium orotate on rats subjected to whole-body gamma-irradiated with doses of 11, 9 and 4 Gy. The preparation exerted a radioprotective action when administered intraperitoneally 60 min before irradiation as was estimated with a reference to the survival rate and leukocyte level in the peripheral blood. Fron the analysis of the peripheral blood consumption it was inferred that potassium orotate weakened the radiation damage and enhanced the recovery processes during the postirradiation period.

A simple approach is proposed to determine locally denatured sites and stability characteristics of secondary DNA structure. The method is based on the analysis of the initial part of melting curve and the determination of changes in the optical density of DNA after heating up to a fixed temperature. The potentiality of the approach is illustrated by the experiments with DNA containing defects in the secondary structure caused by gamma-irradiation in vitro. The sensitivity of the method is less than 0.2 Gy.

Some stages of the apoptotic death of lymphoid cells (thymocytes and peripheral blood lymphocytes) have been followed up using light and electron microscopes. Differences have been revealed in the formation of death stages under natural physiological conditions and after gamma-irradiation. High radiation doses are shown to interfere with the process of nuclear chromatin condensation characteristic of the natural physiological death of cells.

A dose dependence of the number of cells with chromosome aberrations was studied in PHA-stimulated donor's peripheral blood lymphocytes irradiated in vitro with doses of 10-400 cGy. In studying the number of chromosome aberrations and percentage of cells with micronuclei in parallel cultures no correlation was found between these indices within the groups exposed to a similar radiation dose.

The activity of the alpha 1-antitrypsin and alpha 2-macroglobulin were studied in 16 breast cancer patients and 25 hypophyseal adenoma patients prior to and at varying time after proton "hypophysectomy". A high alpha 1-antitrypsin level and a normal alpha 2-macroglobulin level were found in all the breast cancer patients. An increase in both blood serum inhibitors was detected in hypophyseal adenoma. The dependence of the alpha 1-antitrypsin content on a subclinical stage of generalized metastatic spread was revealed in the course of 2 years following "hypophysectomy" in the patients with disseminated breast cancer. In the hypophyseal adenoma patients the activity of both inhibitors returned to normal 1 year after treatment and remained within normal during 3 years of follow-up. It was regarded as a positive therapeutic effect. The above findings make it possible to propose the determination of the activity af alpha 1-antitrypsin in breast cancer and alpha 1-antitrypsin and alpha 2-macroglobulin in hypophyseal adenoma as an additional test for the evaluation of the results of proton "hypophysectomy".

Changes of Macaca nemestrina and Rhesus blood DNA have been studied up to 5 days after the total uniform gamma-irradiation in doses 6.2 and 6.5 Gy. The content of nucleotide ATrich DNA has been evaluated in the fractions of leucocytes with the various surface adherence properties. The dynamics of the content nucleotide AT-DNA and blood leucocytes were similar at the both monkey species. The evaluation of structural state DNA in the blood nucleotide with the fluorescent dyes (ethidium bromide and 4; 6-diamidine-2-phenylindole) demonstrated that the important changes in the polynucleotide structure occurred from 6 to 24 h after irradiation and maintained up to 5 days. Adhesive capacity changes were reversible but they preceded the DNA structural changes. At 24 h postirradiation non-adhesive cells with relative higher AT-DNA content were found.

A study was made of the dynamics of changes in the amino acid composition of erythrocytes, plasma, whole blood and spleen of albino rats during 3 days after total-body uniform gamma-irradiation with doses of 3, 6 and 12 Gy. The change in the amino acid pool of blood and spleen and the ratio between the amino acid concentration in erythrocytes and plasma were shown to depend upon the degree of radiation injury.

A study was made of the postirradiation kinetics of blood antiproteinase activity in monkeys (Macaca nemestrina). Whole-body uniform gamma-irradiation (LD100/45) was shown to induce a significant decrease in the activity of alpha 2-macroglobulin during the first 24 h following irradiation: the decreased activity level was retained throughout the entire latent period of radiation sickness. At the height of radiation sickness (the 7th-10th day) up to the animals' death, a sharp increase was registered in the activity of alpha 1-inhibitor of blood plasma proteinases. The authors discuss a pathogenetic role of the diminution of the inhibitory potential of blood in the course of radiation sickness.

The adherence of peripheral blood leukocyte to a hydrophilic substrate (cotton wool) was studied in healthy donors and patients with Hodgkin's disease and solid tumors. It was shown that neutrophils, eosinophils and lymphocytes contribute to the adhesive ability. Patients with primary solid neoplasms revealed an increased leukocyte adherence. Following a single therapeutic irradiation, this index appeared significantly enhanced in those with Hodgkin's disease. Possible causes of the disturbances are discussed.

Using the method of electrophoresis in agar gel of superhelical plasmid DNA, which served as a substrate for determining endonuclease activity, the authors showed that the same radiation dose influenced in a different way the activity of acid and alkaline DNAases in rat blood serum. At early times (3-6 h) following irradiation, the activity of acid nucleases increased whereas that of alkaline DNAases decreased.

A direct fluorimetric method is elaborated for studying conformational distortions in the scDNA of "nucleoids" of macrophages and thymocytes. The method is more advantageous compared to methods of viscosimetry and sedimentation.

The method of colony chromatography on BND-cellulose was used to study DNA repair synthesis (RS) after gamma-irradiation in PHA-stimulated and nonstimulated lymphocytes. The injury to lymphocytes at the cellular level was estimated by the micronuclear test. The comparison of the data on the rate of RS and the number of cells with micronuclei showed that RS inhibition, in the case of the postirradiation treatment of cells with arabinoside cytosine, leads to a decrease in viability of lymphocyte populations, the G0 cells being primarily damaged.

During the first hours following nonuniform gamma-irradiation (the nonuniformity coefficient was 3:1 and 5:1 with a dose change along the axis directed cranio-caudally and caudo-cranially), endonuclease activity (pH 5.75) in the blood serum increased with the dose which was estimated with a reference to total utilization of the substrate. Supercoiled plasmid DNA served as the substrate. The transformation of a supercoiled form of plasmid DNA into an open circular form was the criterion of estimation of nuclease activity. It was shown that the increase in the nuclease activity correlated with the increase in the nonuniformity coefficient.