[Investigation of detoxification polymorphisms genes, methylenetetrahydrofolate-reductase (MTHFR) and P53 in the radiosensitive human cells].

The genes of detoxication, MTHFR and p53 were studied in Down' and Ehlers-Danlos syndrome cells. The frequency GSTM1(0/0) genotype in Down syndrome patients was in 1.5 times higher than in control cells (p < 0.069). Opposite the frequency GSTM1(0/0) genotype in Ehlers-Danlos syndrome was 23.3% 2 times lower than in control cells (p < 0.034). This indication was in 2 times lower in women cells than in men cells and in 3 times lower than in control cells (p < 0.026). The mutations of p53 gene (7th exon) were detected in 4 from 11 Down patients (36.7%; in 2 cases af women and men), in Ehlers-Danlos patients--in 5 cases and only in men (29.4% among all the observed patients). The observations 24 healthy donors weren't revealed any mutations (p < 0.013-0.001). The hypothesis about the connection between gene polymorphisms which take a part in genome stability and radiosensitivity in Down and Ehlers-Danlos patients was developed.

[Gene polymorphisms in patients with Down's syndrome].

Polymorphisms of glutation-S-transferase (GSTM1, GSTT1 GSTP1) and methylentetrahydrofolate reductase (MTHFR) genes have been studied in DNA from blood lymphocytes of 18 patients with Down's syndrome and 61 controls. Frequencies of normal alleles of GST genotypes were lower in patients as compared to the controls. A DNA analysis of 11 patients and 17 controls revealed the presence of mutations in region 246-250 of exon 7 of the p53 gene in 4 patients. Mutations were not found in the control group. Due to the small sample size, the results of this study should be interpreted with caution and need replication in larger studies.

[The comparison of molecular-biochemical and cytogenetic analyses of blood cells of patients long after the acute radiation sickness].

Molecular-biochemical and cytogenetic analyses were made on blood cells of 17 radiation accident victims who, from 1.7 to 43.8 years previously, had suffered acute radiation sickness (ARS) ranging from severity grades I to IV. Molecular-biochemical data were obtained with patients' leukocytes and with mononuclear cells on their oxidative status by a) the level of an anion-radical O2*- in the 3-(4,5-dimethyl-2-thiazol-2-yl)-2,5-diphenyl-2-tetrazolium bromide (MTT) test and b) the sum of reactive oxygen species in the 2,7-dichlorodihydrofluorescein diacetate (DCFDA) test together with a test for DNA strand unwinding in alkaline conditions by measurements of fluorescence intensity of ethidium bromide. Each parameter was measured in freshly sampled cells and during a 5-hour incubation as absolute means on 5 measurements and in % change from the initial values. Cytogenetic data were obtained from the standard metaphase preparations scored for routine unstable chromosomal aberrations (us-CA)--dicentrics; and stable aberrations (sCA)--translocations. The latter ones were assayed by the FISH method using whole chromosome 2, 4 and 12 fluorescent probes and scaled up to genome equivalence. For all patients reduced oxidative status of about 25-30% was obtained by the MTT-test (p < 0.005), and the DCFDA-test (p < 0.027). The yield of usCA depended on the time after irradiation with higher yields associated with the shorter postirradiation times and reducing almost to expected background frequencies. The yield of sCA was high for all patients, correlating with the severity of ARS whilst the molecular-biochemical parameters showed no relationship with ARS. A correlation was observed between parameters of oxidative status and % of cells with usCA: by the MTT-test r = from 0.50 up to 0.61 (p = from 0.06 up to 0.003), but by the DCFDA-test the strength of correlation was smaller: r = from 0.38 up to 0.48. An inverse correlation was found between initial oxidative state of mononuclear cells and the frequency of CA in lymphocytes. Similarly a marked inverse correlation between degree of DNA unwinding by the ethidium bromide assay on leukocytes and sCA in lymphocytes was also noted. The feasibility of radiation-induced delayed genomic instability in vivo for humans long time after irradiation is discussed.

[The individual prognosis of the gravity and of the outcome of acute radiation disease based on immunological indexes].

The information significance of the immunological indexes for the prognosis of gravity of course and of outcome of an acute radiation disease for the people after the exposure of ionizing radiation in clinically significant doses is studied. The value of indexes of the C-reactive protein contents, of the complement contents and of the titer of haemagglutinins in serum of a blood of 147 patients damaged at Chernobyl NPP accident as a result of external radiation gamma-exposure in combination with internal irradiation from the incorporation in an organism predominantly beta-emitting radionuclides were compared to the weight of acute radiation disease and its outcome (survival or loss). Was determined, that indexes of the contents of C-reactive protein in a peripheral blood during primary reactions on the irradiation (1-2 day after irradiation) and in latent period of disease (3-9 day after irradiation), and also titer of a complement on 3-9 day after irradiation can serve a source of information for the prognosis of probable gravity of a radiation injury and its outcome at irradiation of the man in clinically significant doses.

[Molecular manifestations of radiation-induced genome instability: the possibility of chemical modification].

The molecular manifestations of radiation-induced genome instability-changes of the DNA structure, the excision DNA repair and the contents of the reactive oxygen forms in bone marrow cells of the repair proficient mice (CBA) and of the repair-defective (101/H) lines in the dynamics up to 185 day after ionizing radiation exposure in the dose of 1.5 Gy were studied. Is was established, that after irradiation in bone marrow cells the descendants with the decreased activity of excision DNA repair and prone to increased changes of DNA structure DHK is arised. The injection of the phenozane in concentrations causing its receptor interaction with cells, did not defend DNA of the bone marrow cells from the radiation injury after the exposure in a sublethal dose, however it exerted influence on long-term changes. Due to the phenosane of the bone marrow cells of the irradiated mice of CBA line exhibited the larger activity in a DNA repair from damages and maintenance of vitality. The bone marrow cells of male mice of repair defective 101/H line, which phenozan was entered before the irradiation, remained unfit to the remuval of DNA damages by the repair, that probably resulted the activations of the program of the maintenance of genome constancy by the apoptosis in the cells--carriers of the structural defects and the cause of animal lethality.

[The role of regulatory networks of the cell response to damages in radiation effects].

In view of modern knowledge and concepts about components, function and mechanisms of response of cell molecular structures to damaging effects, response which is generating specialized modules of reactions, it is shown that main components of the mechanism of maintenance of genome constancy at ionizing radiation exposure are checkpoints of cell cycle, DNA repair and apoptosis. They operate under the control of a genetic system at participation of Tp53 gene, corresponding protein and of regulatory networks formed by cascades of mitogen-activated protein kinases (MAPK). At ionizing radiation exposure the MAPK special modules participate in formation of radiation effect: ERK 1/2 (extracellular signal-regulated kinase 1 and 2), JNK/SAPK (c-Jun N-terminal kinase/stress activated protein kinase) and p38 MAPK. Executing physiological functions of maintenance of normal life activity of cells, they do not lose this capacity after exposure to ionizing radiation, participating in formation of radiation effect in a wide range of doses, and are inactivated only by exposure to very high doses. It is concluded that in light of the modern data the main problem is not a problem of mechanisms of biological effect of ionizing radiation but a problem of biological mechanisms of radiation exposure.

[Sexual differences in a state systems of DNA structure maintenance and generation of reactive oxygen species in somatic cells of mice 101/H reparation-defective strain and manifestation of these differences after exposure to ionizing radiation]. / Polovye razlichiia sostoianiia sistem podderzhaniia struktury DNK i generatsii aktivnykh form kisloroda v somaticheskikh v somaticheskikh kletkakh u myshei repearatsionno-defektivnoi 101/H i ikh proiavleniia pri vozdeistvii ioniziruiushchei radiatsii.

To analyse a role of the factor of a genetic fundamentals of cells in formation of radiation-induced genome instability (RIGI) we investigated a condition of DNA pattern, content of superoxide anion-radical O2*- and a sum of reactive oxigen species (ROS) (O2*-, OH*, H2O2), and also catalase activity in bone marrow cells of male and female mice of 101/H strain in the norm and at once after chronic (10 day) exposure to 200 mGy gamma-radiation. Thus we based on conception about a significance of mechanisms of DNA repair and production of reactive oxygen species (ROS) in development of radiation-induced genome instability (RIGI), and also on the data on sex bound differences in efficiency of DNA repair in reply to impact of the genotoxic agents for male and female mice of 101/H strain. Sex connected differences in redox system of bone marrow cells were established. In males lower catalase activity was found in the norm, with considerable increase of the activity and the content of ROS after chronic irradiation with a low dose (200 mGy); at the same time a direct correlation between the ROS content and catalase activity occurred. In female, which have higher DNA repair potential, higher level of catalase activity was found in the norm, with reduction after irradiation and lower, than in male, level of O2*- content; no changes in the general ROS content, or direct correlation between the content of a superoxide anion-radical (O2*-) and the sum of ROS were observed. The detected differences between male and female the studied parameters in the norm and after irradiation indicate a connection of the studied characteristics and their changes with a sex, confirm the literature data about a significance of the factor of a genetic fundamentals of bioobject in formation of radiation-induced genome instability.

[Molecular epidemiology of the late radiation effects]. / Molekuliarnaia épidemiologiia otdalennykh radiatsionnykh éffektov.

The scientific bases, problems, methods and prospects for the development of a new scientific direction "Molecular epidemiology of late consequences of ionizing radiation influence on the man" are reviewed. It is marked, that for two decades on the basis of achievements in the field of molecular biology, biochemistry, genetics and genomics it has arisen and is developing the important direction in infectious and non-infectious epidemiology--molecular epidemiology. Molecular epidemiology is a new section of epidemiology on border with molecular biology and genetics, integrating efforts of epidemiologists, molecular biologists, genetics and researchers from many other areas of knowledge in a direction of an estimation of individual risk of development of chronic diseases at practically healthy people, development of recommendations on their preventive maintenance in cohorts of risk and, hence, in all population by studying by molecular methods of an etiology of illnesses, mechanisms of a susceptibility to them, and also biological mechanisms and frequency of their development in human cohorts. Special development in molecular epidemiology was noticed for the methods named biomarkers, subdivided on 4 categories: 1) markers of an internal dose; 2) markers of an effective dose; 3) markers of preclinical biological effects; 4) markers of a susceptibility. Use of biomarkers in molecular-epidemiological researches appeared especially productive in oncology. As radiogenic cancers are the main remote consequence of exposure to ionizing radiations, approaches and achievements of molecular epidemiology of nonradiation cancers are perspective at becoming of molecular epidemiology of radiation effects, with an object to solve problems concerning mechanisms and features of radiation carcinogenesis, risk assessment, distribution and preventive maintenance of radiogenic cancers in cohorts of professionals of the various branches having contact to sources of ionizing radiation, and the population, exposed to radiation medically.

[Signal function of the reactive oxygen species in regulatory networks of the cell reaction to damaging effects: contribution of radiosensitivity and genome instability]. / Signal'naia funktsiia aktivnykh form kisloroda v reguliatornykh setiakh otveta kletok na povrezhdaiushchie vozdeistviia: uchastie v realizatsii radiochuvstvitel'nosti i nestabil'nosti genoma.

Reactive oxygen species (ROS) have a few possible effects, such as metabolic (participation in regulation of protein functions), damaging (oxidative damage to proteins, lipids and nucleic acids) and signal; the latter is reviewed in the article. Superoxide anion-radical (O2-.), hydroperoxide (HO2) and nitroxide (NO) are capable to act as signal substances in the cell regulatory network, which determines a mode of cell response to disturbance: proliferation pace, a course of differentiation or a start of the apoptosis program. A role of ROS in the reaction network is reviewed: importance of their content in a cell; ROS-bound signal pathways, which trigger the programs of cell reactions to stimuli; initiations of the regulatory network, which determine a content of ROS in a cell; ROS reactions with network components, which influence its functioning. A significance of the ROS-bound segment of the network, which realizes regulatory signals of the damage, in formation of radiobiological effect is estimated. The data obtained by the authors are submitted; the prospects of studing substances (such as phenozan etc.), which can actively influence redox processes, as means of modification of radiation-induced genome instability and prevention of oncogenic transformation are considered.

[On the mechanisms of radiobiological events in relation to the regulatory role of p53 gene and protein]. / O mekhanizmakh radiobiologicheskikh iavlenii v sviazi s reguliatornoi rol'iu gena i belka p53.

The paper analyzes the topical problems of radiobiology in the light of the present-day data on the molecular biology and biochemistry of p53 protein that is an integrator of stress signals from various damaging exposures and that fulfills the function of genome guard by regulating the checking points of a cellular cycle, DNA reparation, and apoptosis. It also considers the mechanisms of radiation cell death and radiosensitivity/radioresistance in the light of data on p53 protein, as well as the problems of searching for antiradiation agents, the radiation-induced instability of genome, the biological aftereffects of small-dose radiation, as well as radiation-induced carcinogenesis due to the important regulatory role of p53 protein. The lines of further studies of the above problems are outlined to refine the understanding of pathogenetic processes in radiation damages, to extend the therapeutic, diagnostic, predictive capacities of clinical radiobiology and radiation medicine.

[Interrelations between the content of reactive oxygen species and the state of DNA structure in bone marrow cells of mice after whole body gamma-irradiation]. / Vzaimosviaz' soderzhaniia aktivnykh form kisloroda i sostoianiia struktury DNK v kletkakh kostnogo mozga u myshei v dinamike posle obshchego vozdeistviia gamma-izlucheniia.

The aim of the research is a further analysis of a problem concerning two (regulatory and damaging) functions of reactive oxygen species (ROS) in viability of organism cells under acute exposure to ionizing radiation. For this purpose the ROS content and the state of DNA structure in bone marrow cells of male CBA and SHK mice have been studied in dynamics, from 15 minutes up to 185 day after acute exposure to a sublethal dose (1.5 Gy) of ionizing radiation. The analysis of dependencies between these parameters in the norm, immediately after irradiation and in later cell descendants showed the direct correlation between the ROS content and the DNA nativity in the norm; 185 days after irradiation the correlation disappeared. It was suggested that the correlation occurred in the norm indicates participation of the ROS (as a sensory link) in a system of reactions (under the control of the corresponding genetic program), that ensure the DNA structure and, ultimately, the genome stability. The loss of such connection after acute exposure to ionizing radiation indicates actuation of another module of reactions sustaining stability of cellular genome in new conditions, without regulatory participation of ROS, that can promote or demonstrate the development of radiation-induced genome instability.

[Dynamic component of maintaining genomic stability in murine bone marrow cells after chronic low-intensity irradiation lasting one year]. / Dinamicheskaii komponent podderzhaniia stabil'nosti genoma v kletkakh kostnogo mozga u myshei posle khronicheskogo oblucheniia nizkoi intensivnosti dlitel'nost'iu odin god.

For analysis of a dynamic component state of the system of maintenance of genome stability, which represent a condition of its expression (first of all, genes of the control of phases of cell cycle, the DNA repair and redox systems) after a long chronic exposure to a small dose, the activity of replicative, reparative DNA synthesis, DNA damage as well as oxyradical content in the bone marrow cells of mice (critical for radiation effects mammalian system) after 1 year radiation exposure to a dose 63.7 cGy (0.17 cGy/day) were studied. The considerable enhancement of replicative and reparative DNA synthesis activity by 67% (p = 0.0033) and 60% (p = 0.000004) accordingly in relation to the control and some, but statistically not significant (p = 0.149) tendency to increase (by 30%) the content of a superoxide anion-radical were established. Strong and highly significant correlation (r = 0.8681; P = 0.99975) between DNA damage and O2-. content in bone marrow cells of the irradiated mices, which indicate the large DNA damage by oxiradicals, probably, due to the loss of a part of structural proteins and conformation changes in expression sites of a chromatin, were detected. The obtained results interpreted as representing the change of a dynamic component state of a system of maintenance of genome stability, the epigenic transfer of that to descendants of the irradiated cells can be the cause for formation and maintenance of radiation-induced genome instability.

[Problems of radiobiology and p53 protein]. / Problemy radiobiologii i belok p53.

The data about the structure and the mechanisms of participation of p53 protein in regulation of the cell cycle checkpoints, DNA repair and apoptosis in normal conditions and after ionizing irradiation are considered. The double strand break of DNA, as a signal of radiation damage, lead to binding of ATM protein with DNA, to appearance of the protein kinase activity at the ATM protein, that after phosphorylation of p53 protein lead to its stabilization and activation. It is noted, that the p53 protein is an integrator of environmental lesion signals, which triggers the transcription, that activate or inhibite the synthesis of protein factors leading to cell cycle arrest in the checkpoints, to increase of DNA repair or to apoptosis. The data evidenced the participation of p53 protein in radioresistance formation are considered: p53 protein after mutation changes loses the control over the cell cycle, DNA repair and apoptosis, and that leads both to the radioresistance increase and to the possibility of the radiation-induced defects retention in progeny of the irradiated cells and organisms. Potential prospective research directions in radiobiology in connection with the data on the molecular biology of p53 gene and protein (the problems of norm, radiosensitivity/radioresistance, drug research for prophylaxe and treatment of radiation injury, low dose effect including by high density irradiation) are reviewed.

[Radiation-induced genomic instability: phenomenon, molecular mechanisms, pathogenetic significance]. / Radiatsionno-indutsiruemaia nestabil'nost' genoma: fenomen, molekuliarnye mekhanizmy, patogeneticheskoe znachenie.

The recent data on the radiation-induced genome instability as a special state of progeny of cells irradiated in vitro as well as after a whole body exposure to ionizing radiation, that make these cells considerably different from normal, unirradiated cells, were considered. This state presents a number of cytogenetical, molecular-biological, cytological and biochemical manifestations untypical for normal cells. The state is controlled by the mechanisms of regulation of checkpoints of cell cycle, and apoptosis, that is under gene p53 control. The proof has been found that this state transfers from irradiated maternal cells to their surviving progeny by the epigenetical mechanisms and would exist until the cells restore the original state of response on the DNA damage. From the point of view of the genome instability conception, that considers the chromatine rearrangement as the adaptive-evolution mechanism of adaptation of the species to changeable environmental conditions, the radiation-induced genome instability may be considered as transition of irradiated progeny to the state of read these to adaptation changes with two alternative pathways. The first leads to adaptation to enviromental conditions and restoring of normal cell functions. The second presents the cell transition into the transformed state with remain genome instability and with increase of tumour growth probability.

[Molecular mechanisms of major radiobiological sequels of the effect of ionizing radiation on mammals]. / O nekotorykh molekuliarnykh mekhanizmakh osnovnykh radiobiologicheskikh posledstvii deistviia ioniziruiushchikh izluchenii na organizm mlekopitaiushchikh.

The modern knowledge about the molecular bases of reproductive cell death, apoptosis, necrosis and disturbance of the cell reproduction, the main causes of radiation sickness and radiation death of mammals and men was considered. It was marked, that these deterministic effects of ionizing radiation as the stochastic effects (mutagenesis and carcinogenesis) have an common molecular basis that most full opened up by study of apoptosis and including in complex genetical and biochemical phenomena of DNA repair.

[Various biochemical determinants and radioresistance markers in the mammalian body]. / Nekotorye biokhimicheskie determinanty i markery radiorezistentnosti organizma mlekopitaiushchikh.

The authors data about the relationship between the organism radioresistance (survival/lethality after lethal doses of irradiation) and RNA/DNA ratio, DNA repair activity in blood cells (that damaged with chemical mutagen, UV- and gamma-rays) and also with oxygen radical forms generation in mononuclear and polymorphonuclear blood leucocytes for allogen molecules and bodies inactivation were resumed. Significance of considered correlation was higher after leucocyte mobilization by bacterial lipopolysaccharide injection. The founded relationship between the biochemical processes and survival (radioresistance) was confirmed on the animal radioresistance/radiosensitivity model, when one give to animals the substances in radioprotective effective or not effective doses. The chromatin expression level and the activity of oxygen radical forms generation systems were considered as the biochemical determinants of radioresistance, and their values--as the markers of this status.

[Indometofen causes biochemical changes in the blood cells characteristic for a radioresistant state of the body]. / Indometofen vyzyvaet v kletkakh krovi biokhimicheskie izmeneniia, kharakternye dlia radiorezistentnogo sostoianiia organizma.

The DNA and RNA contents, RNA/DNA ratio, and spontaneous and latex-induced oxidant activity indices of the whole blood were studied in the nitroblue tetrazolium test of mono- and polymorphonuclear blood leucocytes of intact dogs after injection of lipopolysaccharide pyrogenal. Significant changes in the above parameters were revealed for radioresistant (survived) and radiosensitive (lost) animals exposed to a subsequent prolonged gamma irradiation with a lethal dose of 7.64 Gy (LD75/45). Peroral introduction of 30 mg/kg indometofen (an indole analog of tamoxifen), which is a potential radioprotector, to dogs increased the survival rates of the irradiated dogs up to 93% and aided in the adaptive biochemical changes in the nuclear cell compartment of blood to induce a radioresistant status of the organism.

[Effect of Rhodiola rosea on the yield of mutation alterations and DNA repair in bone marrow cells]. / Vliianie ékstraktov rodioly rozovoi na vykhod mutatsionnykh izmenenii i reparatsiiu DNK v kletkakh kostnogo mozga.

The study was made of the influence of the Rhodiola rosea extracts administration on chromosome aberrations, production of cells with micronuclei and unscheduled DNA synthesis in bone marrow cells of mice under action of mutagens cyclophosphamide and N-nitroso-N-methylurea (NMU). It was found that Rhodiola rosea extracts reduce significantly the yield of cells with the chromosome aberrations and micronuclei induced by cyclophosphamide in vivo, inhibit unscheduled DNA synthesis induced by NMU in vitro. It is emphasized that Rhodiola rosea extracts are antimutagens due to ability to raise the efficiency of the intracell DNA repair mechanisms.

[The effect of the potential antiradiation agent compound HC-1539 on reparative DNA synthesis induced by the damaging action of the chemical mutagen N-nitroso-N-methylurea and radiation]. / Vliianie potentsial'nogo protivoluchevogo sredstva--soedineniia HC-1539--na reparativnyi sintez DNK, indutsiruemyi povrezhdaiushchim deistviem khimicheskogo mutagena N-nitrozo-N-metilmocheviny i izluchenii.

The influence of NS-1539, a potential anti-irradiation agent and indole analogues of tamoxifen on the DNA repair synthesis in the bone marrow and lymphocytes of peripheral blood was studied. It was found that the DNA repair processes from damages caused by chemical mutagen N-nitroso-N-methylurea or physical factor UV-irradiation in the bone marrow cells after the NS-1539 protection of mice as well as in lymphocytes of peripheral blood of human donors were enhanced. The enhancing of DNA repair synthesis was seen not earlier than 18 hours after the NS-1539 injection to mice in vivo or when NS-1539 was added to lymphocyte suspension in vitro and observed up to the third day. This period of time coincides with the time of formation of radioresistance of organism under the influence of this agent as well as with the time of realization effects of steroid hormones on target cells.