BRAIN AND EYE AS POTENTIAL TARGETS FOR IONIZING RADIATION IMPACT: PART II - RADIATION CEREBRO/OPHTALMIC EFFECTS IN CHILDREN, PERSONS EXPOSED IN UTERO, ASTRONAUTS AND INTERVENTIONAL RADIOLOGISTS. / GOLOVNYI MOZOK TA ORGAN ZORU IaK POTENTsIINI MIShENI DLIa VPLYVU IONIZUIuChOGO VYPROMINIuVANNIa: ChASTYNA II ­ RADIATsIINI TsEREBROOFTAL'MOLOGIChNI EFEKTY U DITEI, OSIB, EKSPONOVANYKh VNUTRIShN'O/UTROBNO, ASTRONAVTIV TA INTERVENTsIINYKh RADIOLOGIV.

BACKGROUND: Ionizing radiation (IR) can affect the brain and the visual organ even at low doses, while provoking cognitive, emotional, behavioral, and visual disorders. We proposed to consider the brain and the visual organ as potential targets for the influence of IR with the definition of cerebro-ophthalmic relationships as the «eye-brain axis¼. OBJECTIVE: The present work is a narrative review of current experimental, epidemiological and clinical data on radiation cerebro-ophthalmic effects in children, individuals exposed in utero, astronauts and interventional radiologists. MATERIALS AND METHODS: The review was performed according to PRISMA guidelines by searching the abstract and scientometric databases PubMed/MEDLINE, Scopus, Web of Science, Embase, PsycINFO, Google Scholar, published from 1998 to 2021, as well as the results of manual search of peer-reviewed publications. RESULTS: Epidemiological data on the effects of low doses of IR on neurodevelopment are quite contradictory, while data on clinical, neuropsychological and neurophysiological on cognitive and cerebral disorders, especially in the left, dominant hemisphere of the brain, are nore consistent. Cataracts (congenital - after in utero irradiation) and retinal angiopathy are more common in prenatally-exposed people and children. Astronauts, who carry out longterm space missions outside the protection of the Earth's magnetosphere, will be exposed to galactic cosmic radiation (heavy ions, protons), which leads to cerebro-ophthalmic disorders, primarily cognitive and behavioral disorders and cataracts. Interventional radiologists are a special risk group for cerebro-ophthalmic pathology - cognitivedeficits, mainly due to dysfunction of the dominant and more radiosensitive left hemisphere of the brain, andcataracts, as well as early atherosclerosis and accelerated aging. CONCLUSIONS: Results of current studies indicate the high radiosensitivity of the brain and eye in different contingents of irradiated persons. Further research is needed to clarify the nature of cerebro-ophthalmic disorders in different exposure scenarios, to determine the molecular biological mechanisms of these disorders, reliable dosimetric support and taking into account the influence of non-radiation risk factors.

SOME ISSUES OF LIFE ACTIVITIES OF POPULATION IN THE CHORNOBYL EXCLUSION ZONE IN UKRAINE. / DEIaKI ASPEKTY ZhYTTIeDIIaL'NOSTI NASELENNIa V ChORNOBYL'S'KII ZONI VIDChUZhENNIa UKRAÏNY.

BACKGROUND: Radiation accidents at the Chornobyl Nuclear Power Plant (USSR, 1986) and Fukushima-1 (Japan,2011) have shown that global environmental contamination is an intervention in normal human life making nega-tive effect on population health. These accidents highlighted a number of statutory and regulatory both with me-dical and social problems for individuals, who returned voluntarily for permanent residence in the ChornobylExclusion Zone i.e. a radiation-hazardous area (they are named the «self-settlers¼). OBJECTIVE: generalization of experience in the settlement of normative-legal, ecological-dosimetric and medico-social life issues of population living in the Chornobyl NPP (ChNPP) Exclusion Zone («self-settlers¼). OBJECT AND METHODS: The chosen problem is complex, necessitating the generalization of radiation-hygienic, med-ical-biological, socio-economic, demographic and sociological research results obtained by the national and foreignauthors. A set of theoretical research and analysis of empirical data methods on the principles of interdisciplinaryinteraction was used; the systematic, legal, economic, medical-biological, demographic and retrospective-dosimet-ric approaches of research were applied. RESULTS: It was shown that a part of population refused to evacuate or had returned for permanent residence to theradiation-hazardous lands after the ChNPP accident. In 1986-2009 the number of «self-settlers¼ ranged from 150to 2,000 in different years. In 2021 - the 101 people. Those were mainly people of working age, mostly females, single people or widows/widowers. Рrevious medical and dosimetric studies have shown that long-term residence inthe Exclusion Zone affects physical and mental health of «self-settlers¼ and causes atypical aging, includinginvolvement of the central nervous system. According to calculations, the average effective total radiation doseaccumulated by «self-settlers¼ for the first 3 years was 30 % of dose for the entire post-accident period, and thedose accumulated over 20 years was 54 % of the dose accumulated over 35 years. But the effective radiation dosesaccumulated in different periods after the accident differ significantly in residents of different Exclusion Zone settlements. This information needs further study in terms of the «radiation dose - health status¼ dependence. CONCLUSIONS: The effective radiation doses accumulated in different periods after the accident differ significantlyin the residents of different Exclusion Zone settlements. Тhe average effective total radiation dose accumulated by«self-settlers¼ for the first 3 years was 30 % of the dose for the entire post-accident period, and the dose accumulated over 20 years was 54 % of the dose accumulated over 35 years.

AGING OF THE CHORNOBYL CATASTROPHE SURVIVORS AND PROBLEMS OF THEIR MENTAL HEALTH SURVEY. / STARINNIa POSTRAZhDALYKh VNASLIDOK ChORNOBYL'S'KOÏ KATASTROFY TA PROBLEMY DOSLIDZhENNIa ÏKhN'OGO PSYKhIChNOGO ZDOROV'Ia.

BACKGROUND: Depopulation processes in Ukraine have been affected by the Chornobyl catastrophe (ChC), but therate of demographic aging of survivors remains uncertain. Although the mental health disorders of the survivors arerecognized internationally, problems of their research remain unresolved. Thus, these areas of research are relevant.Objective is to determine the rate of demographic aging of survivors of the Chornobyl NPP (ChNPP) accident and toanalyze the state of their mental health survey, outlining solutions. MATERIALS AND METHODS: Information and statistical sources for 1986-2019 of the Ministry of Health of Ukraine andthe State Statistics Service of Ukraine on the age of the ChC survivors are used. The results of previous own researchand other scientists using the data of the Clinical and Epidemiological Register (CER) of the State Institution«National Research Center for Radiation Medicine of the National Academy of Medical Sciences of Ukraine¼(NRCRM), the State Register of ChC survivors (SRU), and the Department of Radiation Psychoneurology, Institute ofClinical Radiology, NRCRM are integrated. Theoretical, general scientific, demographic and mathematical-statisticalresearch methods and documentary analysis are used. RESULTS: It is shown that in 2018, compared to 1995, the number of the ChC survivors, who are under the supervi-sion of the Ministry of Health of Ukraine, decreased by almost 987 thousand. The part of people born from personsof the 1st-3rd accounting groups increased in the structure of survivors (from 13.1 % in 1995 to 13.6 %), and thisdecreased in persons living or lived in the territories subject to supervision (75.1 % and 63.1 %, respectively), butin evacuees and Chornobyl clean-up workers (liquidators) this did not change significantly. A high level of aging ofthe ChC survivors (except for the 4th group) is revealed: liquidators - 59.0 %; evacuees - 25.0 %, and residents ofradioactively contaminated territories (RCT) - 30.7 %. It has been proved that the countries of RCT differ signifi-cantly in the number of the ChC survivors and their structure. The increase in the post-accident period indicators ofthe level of aging and the average age of the RCT population indicates negative changes in age parameters and theneed to continue research to identify factors «responsible¼ for such changes. Long-term mental health disordersand neuropsychiatric effects in the ChC survivors have been identified - an excess of cerebrovascular pathology andneurocognitive deficits, especially in liquidators, which may indicate an accelerated aging. Radiation risks havebeen revealed for acute and chronic cerebrovascular pathology and organic mental disorders of non-psychotic andpsychotic levels. Neurophysiological and molecular-biological atypia of aging processes under an exposure to lowdoses of and low dose rate of ionizing radiation have been found. The psyche under the age of 40 years old at thetime of exposure is more vulnerable. Existing statistical and registry data underestimate the level of mental disor-ders in the population of Ukraine, including the ChC survivors by an order of magnitude. CONCLUSIONS: The ChC survivors are aging in the country. The negative tendencies in age parameters of survival indi-cate the need to continue research to identify the factors «responsible¼ for such changes. Mental health disordersand neuropsychiatric effects in the ChC survivors are underestimated. It is necessary to create a national psychiatricregistry of Ukraine and long-term (lifelong) monitoring of survivors with well-planned clinical and epidemiologicalstudies of general and mental health with reliable dosimetric support based on national registries using the latest information technologies.

BRAIN AND EYE AS POTENTIAL TARGETS FOR IONIZING RADIATION IMPACT. PART III / FEATURES MORPHOMETRIC RETINAL PARAMETERS, AMPLITUDE AND LATENCY COMPONENTS OF VISUAL EVOKED POTENTIAL IN RADIATION EXPOSED IN UTERO. / GOLOVNYI MOZOK TA ORGAN ZORU IaK POTENTsIINI MIShENI DLIa VPLYVU IONIZUIuChOGO VYPROMINIuVANNIa: ChASTYNA III ­ OSOBLYVOSTI MORFOMETRYChNYKh PARAMETRIV SITChASTOÏ OBOLONKY TA AMPLITUDA I LATENTNIST' KOMPONENTIV ZOROVYKh VYKLYKANYKh POTENTsIALIV U OPROMINENYKh VNUTRIShN'OUTROBNO OSIB.

One of the current problems of modern radiobiology is determine the characteristics of the manifestation of radiation-induced effects not only at different dose loads, but also at different stages of development of the organism. In previous reports, we have summarized available evidence that at certain ages there is a comparative acceleration of radiation-induced pathological changes in the eye and brain, and the study and assessment of the risk of possible ophthalmic and neurological pathology in remote periods after contamination of radioactive areas. Data of irradiated in utero individuals are possible on the basis of observation of the state of the visual analyzer in persons who underwent intrauterine irradiation in 1986. Therefore, a parallel study of retinal morphometric parameters, amplitude and latency of components of evoked visual potentials in irradiated in utero individuals was performed. OBJECTIVE: to evaluate the retinal morphometric parameters, amplitude and latency components of the evoked visual potentials in intrauterine irradiated persons. MATERIALS AND METHODS: The results of surveys of 16 people irradiated in utero in the aftermath of the Chornobyl disaster were used; the comparison group were residents of Kyiv of the corresponding age (25 people). Optical coherence tomography was performed on a Cirrus HD-OCT, Macular Cube 512x128 study technique was used. At the same time, the study of visual evoked potentials on the inverted pattern was performed, and occipital leads wereanalyzed. Visual evoked potentials were recorded on a reversible chess pattern (VEP) - an electrophysiological test, which is a visual response to a sharp change in image contrast when presenting a reversible image of a chessboard. RESULTS: In those irradiated in utero at the age of 22-25 years, there was a probable increase in retinal thickness in the fovea, there was a tendency to increase the thickness of the retina in the areas around the fovea. When recording visual evoked potentials on a reversible chess pattern in this group, there was a tendency to decrease the amplitudes of components (N75, P100, N145, P200) in the right and left parieto-occipital areas and asymmetric changes in latency of these components. CONCLUSIONS: Early changes of fovea recorded in OCT and decreasing amplitudes of components of visual evoked potentials on the reversible chess pattern at the age of 22 25 years may indicate a risk of development in patients irradiated in utero, early age-related macular degeneration, as well as increased risk and increased risk structures of the visual analyzer.

BRAIN AND EYE AS POTENTIAL TARGETS FOR IONIZING RADIATION IMPACT. Part І. THE CONSEQUENCES OF IRRADIATION OF THE PARTICIPANTS OF THE LIQUIDATION OF THE CHORNOBYL ACCIDENT. / GOLOVNYI MOZOK TA ORGAN ZORU IaK POTENTsIINI MIShENI DLIa VPLYVU IONIZUIuChOGO VYPROMINIuVANNIa. Chastyna I. TsEREBROOFTAL'MOLOGIChNI EFEKTY OPROMINENNIa V UChASNYKIV LIKVIDATsIÏ NASLIDKIV AVARIÏ NA ChAES.

BACKGROUND: Exposure to ionizing radiation could affect the brain and eyes leading to cognitive and vision impairment, behavior disorders and performance decrement during professional irradiation at medical radiology, includinginterventional radiological procedures, long-term space flights, and radiation accidents. OBJECTIVE: The objective was to analyze the current experimental, epidemiological, and clinical data on the radiation cerebro-ophthalmic effects. MATERIALS AND METHODS: In our analytical review peer-reviewed publications via the bibliographic and scientometric bases PubMed / MEDLINE, Scopus, Web of Science, and selected papers from the library catalog of NRCRM - theleading institution in the field of studying the medical effects of ionizing radiation - were used. RESULTS: The probable radiation-induced cerebro-ophthalmic effects in human adults comprise radiation cataracts,radiation glaucoma, radiation-induced optic neuropathy, retinopathies, angiopathies as well as specific neurocognitive deficit in the various neuropsychiatric pathology including cerebrovascular pathology and neurodegenerativediseases. Specific attention is paid to the likely stochastic nature of many of those effects. Those prenatally and inchildhood exposed are a particular target group with a higher risk for possible radiation effects and neurodegenerative diseases. CONCLUSIONS: The experimental, clinical, epidemiological, anatomical and pathophysiological rationale for visualsystem and central nervous system (CNS) radiosensitivity is given. The necessity for further international studieswith adequate dosimetric support and the follow-up medical and biophysical monitoring of high radiation riskcohorts is justified. The first part of the study currently being published presents the results of the study of theeffects of irradiation in the participants of emergency works at the Chornobyl Nuclear Power Plant (ChNPP).

DIFFUSION TENSOR MAGNETIC RESONANCE IMAGING IN EARLY DIAGNOSIS OF STRUCTURAL CHANGES IN BRAIN WHITE MATTER IN SMALL VESSEL DISEASE ASSOCIATED WITH ARTERIAL HYPERTENSION AND IONIZING RADIATION. / DYFUZIINO-TENZORNA MRT U RANNII DIAGNOSTYTsI STRUKTURNYKh ZMIN BILOÏ REChOVYNY GOLOVNOGO MOZKU PRY ASOTsIIOVANII Z ARTERIAL'NOIu GIPERTENZIIeIu TA IONIZUIuChYM VYPROMINIuVANNIaM KhVOROBI MALYKh SUDYN.

OBJECTIVE: to determine the early signs of structural changes in brain white matter in small vessel disease associated with arterial hypertension and exposure to ionizing radiation using DTI-MRI. MATERIALS AND METHODS: 45 patients (mean age (57.56 ± 6.34) years) with small vessel disease (SVD) associatedwith arterial hypertension (AH) were examined: group I - 20 patients, participants of liquidation of the accident atthe Chornobyl nuclear power plant (Chornobyl clean-up workers); group II - 25 patients not exposed to ionizingradiation. MRI was performed on an Ingenia 3T tomograph («Philips¼). The fractional anisotropy (FA) was determined in the main associative and commissural pathways, periventricular prefrontal areas (fasciculus fronto-occipitalis superior / anterior - f. FO ant., corona radiata anterior - CR ant.) and semioval centers (SC). RESULTS: No signs of cerebral cortex or brain white matter (WM) atrophy, intracerebral microhemorrhages, and widespread areas of leukoaraiosis consolidation were observed in the examined patients. In the Chornobyl clean-up workers a larger number of foci of subcortical leukoaraiosis was visualized (80 %) on MRI images including multiple -8 (40 %), > 0.5 cm - 10 (50 %), with signs of consolidation - 5 (25 %). The results of the FA analysis in semiovalcenters showed its significant decrease in the patients of groups I and II (p < 0,007), regardless of the presence orabsence of visual signs of subcortical leukoaraiosis (ScLA) (III gr.: 253-317, p < 0.00001; IV gr.: 287- 375,p < 0.001). FA indicators in f. FO ant. and CR ant. in the patients of groups I and II differed insignificantly but weresubstantially lower than controls (p < 0.05). FA was significantly lower, compared to reference levels, in visuallyunchanged f. FO ant. (0.389-0.425; p = 0.015) and CR ant. (0.335-0.403; p = 0.05). In patients with AH-associated SVD of middle age, regardless of the effects of ionizing radiation, no significant changes in FA in the mainWM associative and commissural pathways were found (p > 0.05). CONCLUSIONS: DTI-MRI allows to detect early signs of structural changes in the white matter of the brain - a significant decrease in fractional anisotropy indicators in visually unchanged periventricular and subcortical areas. Themain associative and commissural pathways of the brain remain intact in the absence of widespread consolidatedfoci of leukoaraiosis and lacunar infarctions. The negative impact of ionizing radiation on the course of SVD associated with arterial hypertension is manifested by more active processes of WM disorganization: the prevalence andtendency to the consolidation of periventricular and subcortical leukoaraiosis foci, a significant FA decrease in semioval centers.

NEUROENDOCRINE EFFECTS OF PRENATAL IRRADIATION FROM RADIOACTIVE IODINE (review). / NEY̆ROENDOKRYNNI EFEKTY PRENATAL'NOGO OPROMINENNIa RADIOAKTYVNYM Y̆ODOM (ogliad).

BACKGROUND: Neuroendocrine effects of the prenatal radiation exposure from radioactive iodine in an event of nuclear power reactor accidents are a key issue in the field of radiation medicine and radiation safety because of a dramatic radiosensitivity of the developing organism. OBJECTIVE: Review of contemporary epidemiological, clinical and experimental data on neuroendocrine effects of prenatal exposure to 131I. OBJECT AND METHODS: Search in the PubMed/MEDLINE and Google Scholar abstract databases, along with a manual search for the relevant data sources. RESULTS: Estimated absorbed doses of intrauterine thyroid irradiation from radioactive iodine were obtained based on ICRP Publication 88, both with estimates of effective radiation doses on embryo and fetus, and estimates of the brain equivalent doses upon exposure in utero. The latter ones are subject to updating. The evidence-based data has been presented regarding a radiation-associated reduction of head and chest circumference at birth, as well as a radiation-associated excess of goiter with large thyroid nodules, and possibly of thyroid cancer after a prenatal exposure to 131I radionuclides. Data on intrauterine brain damage are controversial, but most researchers share the view that there are cognitive and emotional-behavioral disorders due to prenatal and postnatal irradiation and psy- chosocial impacts. Incidence increase of non-cancerous endocrine disorders and degenerative vascular disease of retina was noted. An experimental model of intrauterine irradiation from 131I on Wistar rats was for the first time ever created, extrapolating the radioneuroembryological effects in rats to individuals prenatally exposed after the Chornobyl disaster. Late neuropsychiatric and endocrine effects may be resulted from the relatively short-term impact of ionizing radiation at a level previously been considered safe. The necessity of neuropsychiatric and endocrinological monitoring of individuals exposed prenatally to ionizing radiation after the Chornobyl catastrophe throughout their life is substantiated. Experimental animal studies are a key direction in the further research of radiation effects, especially associated with low radiation doses. Further experimental and clinical neuroradiobio- logical studies aimed at exploration of the effect of ionizing radiation on hippocampal neurogenesis are most rele- vant nowadays.

[HYPERPARATHYROIDISM AND PARATHYROID LESIONS IN THE ChNPP ACCIDENT SURVIVORS]. / GIPERPARATYREOZ TA URAZhENNIa PRYShchYTOPODIBNYKh ZALOZ U OSIB, OPROMINENYKh VNASLIDOK AVARIÏ NA ChAES.

OBJECTIVE: Study of the status of parathyroid glands in individuals exposed to ionizing radiation as a result of the ChNPP accident and comparison with the general population of Ukraine. MATERIALS AND METHODS: Subjects exposed as a result of the ChNPP accident (n = 1,348) and people from the general population of Ukraine (n=655) were examined. Diagnostic ultrasound scan of thyroid and parathyroid glands (PTG) was conducted in all study subjects. The technique of parathyroid ultrasound screening was developed, which led to an increase in the efficiency of their imaging. Additionally, the 25-hydroxyvitamin D (25(OH)D), parathyroid hor- mone, ionized calcium and some other parameters were selectively assayed in serum. RESULTS: High incidence of parathyroid hyperplasia was detected 27-32 years after the irradiation in persons ex- posed as a result of the ChNPP accident, especially in evacuees from the 30-km exclusion zone (71.4%; χ2Yates' = 24.1; р = 0) and residents of radilogically contaminated territories (41.7%; χ2Yates' = 6.45; p < 0.01) having no primary hyperparathyroidism. High prevalence of vitamin D insufficiency and deficiency was revealed in all study subgroups, namely in 83.1 % of the general population of Ukraine along with a bit better vitamin D status in the ChNPP acci- dent survivors i.e. the vitamin insufficiency and deficiency was found in 78.7 % of them. Incidence of hyperparathy- roidism, predominantly of the secondary (normocalcemic) one, was 33.8 % among persons exposed as a result of the ChNPP accident (p > 0.3) being somewhat higher than in the general population of Ukraine (26.1%), despite above- mentioned better supply of vitamin D. CONCLUSIONS: There is a widespread insufficiency or deficiency of vitamin D (over 78.7%) in the population of Ukraine in general providing an unfavorable background for the higher prevalence of health disorders associated with calcium and phosphorus metabolism. The latter features parathyroid hyperplasia and musculosceletal, immune, cardiovascular, and endocrine system comorbidities. Such disorders should exacerbate with a secondary increase in parathyroid hormone secretion (26.1 %). Higher incidence of normocalcemic hyperparathyroidism (33.8% versus 26.1%) against a background of better vitamin D status among irradiated individuals indicates the existence of other factors, where the past combined effects of Chornobyl radioactive fallout and external parathyroid exposure are most likely to be involved. This could explain the greater number of cases of parathyroid hyperplasia and hyper- parathyroidism among the exposed subjects. However the additional precise studies are required here with clarifi- cation of the personal data in population groups of the ChNPP accident survivors. Participants of the ChNPP acci- dent clean-up work in the «iodine period¼ of 1986 are of especial concern here. Besides that, the study population should be expanded with inclusion of subjects exposed in prenatal period.

STATE INSTITUTION «NATIONAL RESEARCH CENTER FOR RADIATION MEDICINE OF THE NATIONAL ACADEMY OF MEDICAL SCIENCES OF UKRAINE¼ - RESEARCH ACTIVITIES AND SCIENTIFIC ADVANCE IN 2017. / REFORMUVANNIa SYSTEMY OKhORONY ZDOROV'Ia: ROL' I MISTsE ZAKLADIV OKhORONY ZDOROV'Ia TRETYNNOGO RIVNIa PRY RADIATsIINYKh NADZVYChAINYKh SYTUATsIIaKh V UMOVAKh VOIeNNOGO STANU.

The role and place of health care facilities of the highly specialized (tertiary) level in radiation emergencies in the conditions of martial law are considered taking into account the experience of overcoming of the Chornobyl catas-trophe consequences. The classification of emergencies and the main scenarios of radiation emergencies (nuclear terrorism, radiation accidents and incidents, the use of nuclear weapons) are presented. The principles of medical preparedness and providing the highly specialized medical care in a radiological emergency are presented on the base of the Chornobyl catastrophe experience. It is determined that the tertiary health care facilities in a radiological emergency should provide as follow: development and implementation of plans and protocols of highly specialized medical care; organization, direct provision, coordination and quality control of the highly specialized medical care; aggregation and coordination of efforts of all three levels of health care facilities; integration into the radiation emergency management system, and analysis and generalization of the experience gained.

NEUROPSYCHOBIOLOGICAL MECHANISMS OF AFFECTIVE AND COGNITIVE DISORDERS IN THE CHORNOBYL CLEAN-UP WORKERS TAKING INTO ACCOUNT THE SPECIFIC GENE POLYMORPHISMS. / NEIROPSYKhOBIOLOGIChNI MEKhANIZMY AFEKTYVNYKh I KOGNITYVNYKh ROZLADIV V UChASNYKIV LIKVIDATsIÏ NASLIDKIV AVARIÏ NA ChORNOBYL'S'KII AES Z URAKhUVANNIaM POLIMORFIZMU GENIV.

Relevance of the present work is determined by the considerable prevalence of both affective and cognitive disor-ders in the victims due to the Chornobyl accident, the pathogenesis of which is insufficiently studied.Objective is to identify the neuropsychiobiological mechanisms of the formation of the remote affective and cog-nitive disorders following exposure to ionizing radiation taking into account the specific gene polymorphisms.Design, object and methods of research. The retrospective and prospective cohort study with the external andinternal control groups. The randomized sample of the male participants in liquidation of the consequences of theaccident (Chornobyl clean-up workers, liquidators) at the Chornobyl nuclear power plant (ChNPP) in 1986-1987(n = 198) recruited from the Clinico-epidemiological registry (CER) of NRCRM aged 39-87 (M ± SD: 60.0-8.5 years)with the external irradiation dose ranged 0.6-5900.0 mSv (M ± SD: 456.0 ± 760.0 mSv) was examined. The compar-ison group (n = 110) consisted of the unexposed patients of the Radiation Psychoneurology Department with thecorresponding age and sex (the external control group). The internal control group included the liquidators irradi-ated at doses < 50.0 mSv (n = 42). The standard diagnostic neuropsychiatric scales, psychodiagnostic questionnairesand tests, neuropsychological methods (including the Wechsler Adult Intelligence Scale (WAIS) with premorbid IQ(pre-IQ) assessment), neuropsychiatric and psychophysiological methods (quantitative EEG (qEEG) and the audito-ry cognitive evoked potentials (Event-Related Potentials, ERP) were applied. The genotypes of the serotonin trans-porter gene SLC6A4 were determined by the 5_HTTLPR and rs25531 polymorphisms. The methods of descriptive and vari-ation statistics, non-parametric criteria, regression-correlation analysis, survival analysis by Kaplan - Meier and riskanalysis were used.Results. Cerebrovascular diseases, organic mental and depressive disorders, mainly of radiation-stress-relatednature, prevail among the liquidators. The overall risk of neuropsychiatric pathology increases (Pv < 0.001) with theirradiation dose. The verbal memory and learning are impaired, as well as the full IQ is reduced at the expense of theverbal one. The frequency of both mild cognitive impairment and dementia is risen. The cognitive impairment atdoses > 0.3 Sv is dose-dependent (r = 0.4-0.7; p = 0.03-0.003). Affective disorders (depression) and neurocogni-tive deficit are more severe at higher doses of irradiation (> 50 mSv). In the left posterior temporal region(Wernicke's area) the qEEG indices changes become dose-dependent at doses greater than 0.25-0.3 Sv. The dis-turbed brain information processes lateralized to the Wernicke's area are observed even at doses > 50 mSv. The car-riers of intermediate and low-level genotypes (LА/S, LА/LG, LG/LG, LG/S, S/S) of the serotonin transporter gene SLC6A4have more depressive disorders, especially severe ones, and tend to have more frequent and severe cognitive andstress-related disorders.The debut of depressive disorders in the carriers of the intermediate and low-activity genotypes occurs much earli-er (Log-Rank Test = 4.43, p = 0.035) in comparison with the carriers of the high-performance genotype LА/ LА.Conclusions. The radiation-induced dysfunction of the cortico-limbic system in the left dominant hemisphere ofthe human brain with a specific involvement of the hippocampus is considered to be the key cerebral basis of post-radiation organic brain damage. The association of genotypes by 5_HTTLPR and rs25531 polymorphisms of the SLC6A4gene with affective and cognitive disorders suggests the presence of neuropsychobiological features of these dis-orders associated with ionizing radiation depending on the certain gene polymorphisms.

COMPARATIVE CHARACTERISTIC OF «ALCOHOL DEPRESSION¼ IN PERSONS WHO PARTICIPATED IN COMBAT OPERATIONS (COMBATANS) AND AFFECTED BY RADIATION CATASTROP. / PORIVNIaL'NA KhARAKTERYSTYKA «ALKOGOL'NYKh DEPRESII¼ V OSIB, IaKI BRALY UChAST' U BOIOVYKh DIIaKh (KOMBATANTIV) I POSTRAZhDALYKh PRY RADIATsIINII KATASTROFI.

The relevance of work is conditioned by the considerable prevalence of depressive disorders and alcohol abuseamong people who participated in combat operations (combatants) and affected by a radiation emergency, whichneeds to be optimized for providing them with a comprehensive social, psychological-psychiatric, medication andsomato-neurological help on the basis of a biopsychosocial paradigm.The objective of the study was to increase the level of medical care to combatants of the Antiterrorist Operation /Joint Forces Operation (ATO/JFO) and person affected by the catastrophe at the Chornobyl NPP (ChNPP) with depres-sion associated with alcohol abuse through theoretical substantiation, development and implementation in theinstitutions of public health and other agencies involved of new principles and algorithms for diagnosis, treatmentand prevention.The object and methods of the study were 160 ATO/JFO combatants from the age of 22 to 56 years old (M ± SD:(41.5 ± 16.5) years) with alcohol and depressive disorders the main group. The comparison groups included 81Chornobyl catastrophe clean-up workers (liquidators) with post-traumatic stress disorder and comorbid chroniccerebrovascular pathology, as well as other contingents affected by the Chornobyl catastrophe. Clinical-anamnestic,socio-demographic, clinical psychopathological, psychodiagnostic, neurophysiological and neuroimaging methodswere used. Somato-neurological clinical examinations and laboratory tests have been applied. The analysis of thedata was performed using MS Excel spreadsheets and statistical package Statistica 10.0 (StatSoft) with the Studentt-criterion, paired t-test, criterion χ2, and Fisher exact test.The study design of the main group consisted of 5 stages: 1) screening; 2) inclusion; 3) randomization; 4) treat-ment and 5) catamnestic (follow-up) observation.Results. In the main group the distribution of depressive syndromes was revealed as follows: depressive-hypochon-dric - in 68 (42.5 %) patients; 2) asthenic-depressive - in 33 (20,6 %); 3) anxiety-depressive - in 31 (19.4 %); 4)depressive-dysphoric - in 14 (8.8 %); 5) apathetic-depressive - in 7 (4,35 %); and 6) simple depressive - in7 (4,35%). The combatants after participation in the ATO/JFO had personality deformation and irritative changes of thebrain bioelectric activity, thickening of the intima-media complex and venous dyshaemia in the basal veins ofRosenthal. In liquidators there is an excess of depressive disorders, the frequency and severity of which increase inproportion to the radiation dose. These disorders are characterized by progressive course, personality changes withpsychosomatic pre-disposition, comorbidity with cerebrovascular pathology, neurocognitive deficits and high fre-quency (24 %) of secondary alcohol abuse. The relationship between depressive disorders and alcohol dependencein the examined patients is diverse. Their variants differ in certain clinical manifestations and to a large extentdetermine the differential diagnosis and differentiated approaches to treatment, prevention and medical and socialrehabilitationConclusions. The comorbidity of depressive disorders with the abuse of alcohol by combatants and person affectedby the catastrophe at the ChNPP is gaining an increasing significance first of all because of the increased risk of suicidal behavior. The proposed diagnostic complex and differentiated approaches to treatment, prevention and med-ical and social rehabilitation may increase the level of medical care for the ATO /JFO combatants and the Chernobylcatastrophe survivors with depression associated with alcohol abuse.

BIOLOGICAL MARKERS OF EXTERNAL AND INTERNAL EXPOSURE IN SHELTER CONSTRUCTION WORKERS: A 13-YEAR EXPERIENCE.

OBJECTIVE: The aim of this study is to investigate the cellular, molecular, genetic and non-invasive functional biomarkers of occupational irradiation in workers exposed to a combination of external gamma-radiation and incorporation of transuranium elements. RESULTS: A study was performed in 688 radiation workers of Shelter object conversion into a safe system with mean shift dose of external exposure of 26.06 mSv (range: 0.1-113.35) and risk of internal exposure with transuranium elements. Several biological parameters could serve as biomarkers of exposure at radiation doses below 100 mSv and even in 20-50 mSv interval. The parallel changes were shown in decline of brain electric activity, telomere length, differences in CCND1, CDKN1A, CDKN2A, VEGFA, TP53, DDB2 genes expression. An increase in counts of dicentrics, pair fragments and TCR-variant lymphocytes at doses over professional limits shows the need of biological dosimetry. The most sensitive markers include TCR-CD4+, γ-H2AX+ and CyclinD1+ cell counts. Implementation of flow cytometry approach for these markers enables quick obtaining of quantitative data. Confounding factors included respiratory function and smoking. The study of the radiation workers with the history of chronic exposure in radiation area during 3-5 years demonstrates changes of compensatory origin, i.e. absence of telomere shortening, increased number of NK-cells in combination with lower expression of intracellular γ-H2AX. CONCLUSION: This study confirms the presence of radiation-induced changes in gene regulation of cell proliferation, telomere function and apoptosis in radiation workers exposed to external and internal exposure at doses above professional limits and increase of compensatory changes.

Psychosocial state of the adult evacuees and risk factors of negative change. / SOTsIAL'NO PSYKhOLOGIChNYY̆ STAN DOROSLOGO EVAKUY̆OVANOGO NASELENNIa. FAKTORY RYZYKU NEGATYVNYKh ZMIN.

Numerous scientific studies have been carried out since the ChNPP accident indicating that the last one has caused a severe psychosocial stress in survivors. Population of radioactively contaminated territories, people migrated from the areas of strict radiation control, and accident consequences clean up participants in 1986 1987 were covered by the conducted research projects. Nature of the stress herewith is polygenic and includes factors directly related to the Chernobyl catastrophe, and factors being a result of social and economic circumstances. This report is devot ed to the results of research on psychosocial state of population evacuated from the 30 km zone of the ChNPP. OBJECTIVE: Study and evaluation of psychosocial state of population evacuated from the 30 km ChNPP zone at the age of 18 years and older; identification of potential psychosocial risk factors for the health loss. MATERIALS AND METHODS: The sampling epidemiological study of psychosocial state of population aged 18-50 years evacuated from the 30 km zone of ChNPP was conducted at the NRCRM Radiation Registry Outpatient Clinic and Radiation Psychoneurology Department. The study subjects (n=258) were mostly (98%) females. Study was con ducted from October 2013 till May 2015. All the sample members were registered since 1992 in the system of life long health monitoring, i.e. the NRCRM Clinical and Epidemiological Registry. Study subjects were interviewed through the method using an original «Questioning Inventory¼. Mathematical processing of study results was held using the Epi Info 7 software package. RESULTS: According to the study results, a nuclear accident at the Chornobyl NPP has become a powerful psychoso cial stress for evacuated people. Psychosocial state of the evacuees, formed during the post accident period, with full reason can be defined as a state of stable, chronic psychosocial stress. Nature of factors that caused the stress development is polygenic. Block of stressors directly related to the accident was determined, namely there were «change of radiation and ecological situation¼, «ionizing irradiation¼, «evacuation¼, and «radical breaking of dynamic stereotype of behavior and life¼. In parallel there was selected a block of stress factors generated by that background, i.e. psychological, social, economic, and cultural, on which a nuclear disaster was imposed upon. The effects of stress have manifested as a persistent syndrome of «anxiety¼ for the personal health and health of fami ly members, primarily the children, and as a stable state of «dissatisfaction¼ with fullness and quality of life. CONCLUSIONS: The nuclear accident at the ChNPP has been the cause of a strong psychosocial stress in adult evacu ated population, especially in women. Further in a remote period the stress was transformed into a stable, chronic form. Nature of stress is polygenic and includes stressors directly related to the accident, and stressors that are not directly related to the accident consequences, but are due to the level of social, economic, medical, and informa tional protection of survivors. Data presented in the paper are rather enough important for the formation of strate gies and measures for social and psychological protection of population in an event of nuclear accidents and incidents.

Evoked bioelectrical brain activity following exposure to ionizing radiation. / VYKLYKANA BIOELEKTRYChNA AKTYVNIST' GOLOVNOGO MOZKU PISLIa VPLYVU IONIZUIuChOÏ RADIATsIÏ.

The article provides an overview of modern physiological evidence to support the hypothesis on cortico limbic sys tem dysfunction due to the hippocampal neurogenesis impairment as a basis of the brain interhemispheric asym metry and neurocognitive deficit after radiation exposure. The importance of the research of both evoked poten tials and fields as a highly sensitive and informative method is emphasized.Particular attention is paid to cerebral sensor systems dysfunction as a typical effect of ionizing radiation. Changes in functioning of the central parts of sensory analyzers of different modalities as well as the violation of brain integrative information processes under the influence of small doses of ionizing radiation can be critical when determining the radiation risks of space flight. The possible long term prospects for manned flights into space, including to Mars, given the effects identified are discussed. Potential risks to the central nervous system during space travel comprise cognitive functions impairment, including the volume of short term memory short ening, impaired motor functions, behavioral changes that could affect human performance and health. The remote risks for CNS are considered to be the following possible neuropsychiatric disorders: accelerated brain aging, Alzheimer's disease and other types of dementia. The new radiocerebral dose dependent effect, when applied cog nitive auditory evoked potentials P300 technique with a possible threshold dose of 0.05 Gy, manifesting in a form of disruption of information processing in the Wernicke's area is under discussion. In order to identify neurophys iological biological markers of ionizing radiation further international researches with adequate dosimetry support are necessary.

Cerebral impact of prenatal irradiation by 131I: an experimental model of clinical neuroradioembryological effects. / VPLYV PRENATAL'NOGO OPROMINENNIa 131I NA GOLOVNYY̆ MOZOK: EKSPERYMENTAL'NA MODEL' KLINIChNYKh NEY̆RORADIOEMBRIOLOGIChNYKh EFEKTIV.

Human brain in prenatal period is a most vulnerable to ionizing radiation body structure. Unlike atomic bombings or radiological interventions in healthcare leading at most to external irradiation the intensive internal exposure may occur upon nuclear reactor accidents followed by substantial release and fallout of radioactive 131I. The latter can lead to specific neuroradioembryological effects. OBJECTIVE: To create an experimental model of prenatal cerebral radiation effects of 131I in human and to determine the experimental and clinical neuroradioembryological effects.Study object. The neuroradioembryological effects in Vistar rats exposed to 131I in prenatal period. Nervous system status and mental status in 104 persons exposed to ionizing radiation in utero due to the ChNPP accident and the same in 78 not exposed subjects. METHODS: Experimental i.e. behavioral techniques, including the spontaneous locomotive, exploratory activity and learning ability assessment, clinical i.e. neuropsychiatric, neuro and psychometric, neuropsychological, neurophys iological methods, both with dosimetric and statistical methods were applied. RESULTS: Intrauterine irradiation of Wistar rats by 131I was simulated on a model of one time oral 27.5 kBq radionu clide administration in the mid gestation period (0.72±0.14 Gy fetal thyroid dose), which provides extrapolation of neuroradioembryological effects in rats to that in humans exposed to intrauterine radiation as a result of the Chornobyl catastrophe. Abnormalities in behavioral reactions and decreased output of conditioned reflex reactions identified in the 10 month old rats suggest a deterioration of cerebral cognition in exposed animals. Specific cog nitive deficit featuring a disharmonic intellectual development through the relatively decreased verbal intelligence versus relative increase of nonverbal one is remained in prenatally exposed persons. This can indicate to dysfunc tion of cortical limbic system with especial involvement of a dominant hemisphere hippocampus. Decreased theta band spectral power (4-7 Hz range) of cerebral bioelectrical activity in the left frontotemporal area is suggestive of hippocampal dysfunction mainly in dominant hemisphere of prenatally irradiated persons. Disorders of hippocam pal neurogenesis due to prenatal exposure by radioactive iodine can be a biologic basis here. Innovative approach es in social adaptation, psychoprophylaxis and psychorehabilitation involve the maximum effective application and development of just the most developed psychological and cognitive abilities in survivors.

Influence of polymorphic variants of the SLC6A4 gene on the frequency of detection of depressive states in the group of the clean up workers of consequences of Chornobyl accident in the remote period after the Chornobyl catastrophe. / VPLYV POLIMORFNYKh VARIANTIV GENA SLC6A4 NA ChASTOTU VYIaVLENNIa DEPRESYVNYKh STANIV V GRUPI ULNA NA ChAES U VIDDALENOMU PERIODI PISLIa ChORNOBYL'S'KOÏ KATASTROFY.

Mental disorders of the victims are one of the important medical consequences of the Chornobyl accident. It is also known that in the implementation of the pathogenesis of depressive states a significant role belongs to the sero tonin transporter gene (SLC6A4). OBJECTIVE: To determine the effect of polymorphic variants of the SLC6A4 gene on the frequency of detection of depression in a group of clean up workers in the remote period after the Chornobyl catastrophe. METHODS: The study was conducted in a group of 59 victims of the Chornobyl NPP accident, divided into two groups (without depression and with depressive symptoms). The diagnosis of depressive disorders was based on a compre hensive assessment of the complaints of the surveyed, the clinical and psychopathological data, the values of the Zung Self Rating Depression Scale (SDS), the Brief Psychiatric Rating Scale (BPRS), the General Health Questionnaire (GHQ 28). DNA from the peripheral blood mononuclear cells was isolated, and the 5 HTTLPR polymorphism was determined by polymerase chain reaction (PCR). RESULTS: Depressive symptoms were more often found among reconvalescents of acute radiation sickness (ARS) than in the clean up workers without ARS: (p = 0.006). The tendencies of the association of the received dose of exter nal exposure with the number of points on the SDS scale (r = 0.284; p = 0.043), the sum of scores on the BPRS scale (r = 0.686; p = 0.001), depression (r = 0.323, p = 0.017) and its severity (r = 0.273; p = 0.051) were found. Among the examined clean up workers, in comparison with a large group of Europeans without mental disorders, an increase in the number of carriers of the genotype S/S SLC6A4 was found (p = 0.03). Only for the carriers of the S/S genotype, the reciprocal association between the development of depression and the age of the patient was found: r = 0.503 (p = 0.033), between the development of depression and the time from the ChNPP accident: r = 0.581 (p = 0.011), as well as positive correlation of development of depression with dose of irradiation: r = 0.515 (p = 0.025). Among people aged 55 and older, the development of depression was associated with a decrease in the frequency of high ly functional genotype LА/LА to 4.76% versus 31.25% in the absence of depressed symptoms (p = 0.042). In the group of younger patients, the distribution of genotypes did not differ depending on the signs of depression (p = 0.476). CONCLUSION: The pilot analysis of the distribution of genotypes of the SLC6A4 gene for polymorphisms of 5 HTTLPR and rs25531 in the clean up workers group showed the promise of further studies of the contribution of LА/LА і S/S genotypes to the development of depressive states in combination with the action of the radiation factor.

Myastenia and small doses of ionizing radiation: experience of successful use of rituximab for treatment of an irradiated with myasthenia gravis. / MIASTENIIa I MALI DOZY IONIZUIuChOÏ RADIATsIÏ: DOSVID USPIShNOGO ZASTOSUVANNIa RYTUKSYMABU DLIa LIKUVANNIa OPROMINENOGO Z MYASTHENIA GRAVIS.

A clinical case of the rituximab («Rituksim¼, «Mabthera¼) use to treat a man affected by the Chornobyl NPP acci dent with malignant resistant form of myasthenia gravis in conjunction with chronic mixed infection by Toxoplasma, Epstein Barr virus, Cytomegalovirus and Herpes simplex virus is described. In the dynamics of two year's observa tion the clinical efficacy of monoclonal antibodies was shown as the main symptoms stabilization and reducing doses of glucocorticoid and anticholinergic therapy. The positive effect was marked in the nearest and remote peri ods. Taking to account the efficacy, safety and good tolerability of rituximab, it is advisable to recommend treat ment for people exposed to ionizing radiation and developing myasthenia associated with chronic mixed infection by Toxoplasma, Epstein Barr, Cytomegalovirus and Herpes simplex virus.

Psychophysiological characteristics in the ChNPP accident clean-up workers, exclusion zone evacuees and anti-terrorist operation servicemen. / PSYKhOFIZIOLOGIChNI OSOBLYVOSTI UChASNYKIV AVARIÏ NA ChAES, EVAKUY̆OVANYKh IZ ZONY VIDChUZhENNIa TA UChASNYKIV ANTYTERORYSTYChNOÏ OPERATsIÏ.

OBJECTIVE: Evaluation of interdependencies between psychometric parameters and spontaneous cerebral electric activity in the ChNPP accident clean up workers, evacuees from exclusion zone, and anti terrorist operation service men. OBJECT AND METHODS: Psychometric and neurophysiological parameters were reviewed in the study subjects retro spectively and in comparison. Study population included the ChNPP accident clean up workers (ACUW), evacuees from the 30 kilometer exclusion zone, specifically in a sample from a cohort of the NRCRM Clinical Epidemiological Register (n=316), and anti terrorist operation servicemen (n=81) undergoing rehabilitation in the NRCRM Radiation psychoneurology department. A control group of persons (n=84) was also involved in the study. Diagnostic method ology for the characteristic personality features, namely the personality test of character accentuation by G. Shmishek and K. Leonhard, and Eysenck Personality Inventory (by H. J. Eysenck) were applied. Computer EEGs were registered and analyzed on the 16 channel electroencephalograph DX 4000 (Kharkiv, Ukraine). RESULTS: In the aftermath of the emergency period, a personality deformation occurs in the clean up workers and survivors of the ChNPP accident, which is characterized by aggravation of such personality traits as jam (fixedness), emotiveness, pedantry, anxiety, cyclothymia, excitability and disthymia, with diminished hyperthymia and ostenta tion (demonstrability). Increased incidence of fixedness, pedantry, cyclothymia, affectability and disthymia with decreased hyperthymia were revealed in the group of ATO participants. Cerebral bioelectrical activity in the ChNPP ACUW was characterized by an increased delta activity power with decreased beta and theta activity power and dom inant frequency in comparison with all groups of survivors and control group. The ATO group was different from groups of survivors and control group with a lower power of delta, theta and beta activity, and a higher dominant frequency. Introversion featured a negative correlation with delta and theta activity index along with positive cor relation with alpha activity index. The absolute spectral power of beta, alpha and theta bands positively correlated with introversion. Increase in neuroticism featured a decrease in theta activity index and an increase in beta activ ity index along with decreased theta and delta band absolute spectral power. CONCLUSIONS: There is a deformation of personality in the group of ChNPP ACUW, evacuees from the 30 kilometer zone and ATO servicemen. Deformation of personality correlates with abnormal cerebral bioelectrical activity.

Ionizing radiation: brain effects and related neuropsychiatric manifestations. / IONIZUIuChA RADIATsIIa: VPLYV NA GOLOVNYY̆ MOZOK TA NEY̆ROPSYKhIATRYChNI PROIaVY.

Recently, an increasing interest has been directed towards the investigation of brain effects of ionizing radiation (IR), as it is now evident that, depending on the doses, the damages character and severity, as well as clinical man ifestations are different. They are generally considered to be the result of a blending of atherosclerotic, cardiovas cular, cerebrovascular and neurodegenerative processes. Further, an ongoing debate has been opened on the pos sible brain abnormalities following medical radiation from X ray in interventional radiology and nuclear medicine procedures that would involve both patients and medical workers. The aim of the present paper is to summarize literature data on brain effects of IR exposure, with a special focus on those gathered by some of the authors after the Chornobyl nuclear plant disaster, and how they can be related to the pathophysiology of different neuropsy chiatric disorders.

Social and psychological state of the Chornobyl clean up workers. Risk factors for negative changes. / SOTsIAL'NO PSYKhOLOGIChNYY̆ STAN UChASNYKIV LNA NA ChORNOBYL'S'KIY̆ AES. FAKTORY RYZYKU NEGATYVNYKh ZMIN.

It is generally recognized that the Chornobyl nuclear accident caused strong psychosocial stress affecting the entire population of Ukraine, primarily people involved in recovery operations. But what are the reasons? What is the struc ture of stressors? What are their social, medical and biological consequences, what are strategy and preventive meas ures? Issues that require special research and development. OBJECTIVE: To study social and psychological state of the Chornobyl cleanup workers 1986-1987, and to determine regularities of changes and dangerous risk factors. MATERIALS AND METHODS: On the basis of Polyclinic of Radiation Registry, NRCRM, we conducted sample epidemiolog ical study of social and psychological state of the Chornobyl clean up workers 1986-1987. We used method of inter viewing based on «questionnaire¼, specially developed for this purpose. The study was conducted in October 2013 - May 2015. The sample numbered 235 males aged 18-50 at the time of the accident. Their average age was (31.3 ± 5.3) years at the time of the accident and (58.9 ± 5.3) at the time of survey. RESULTS: The results revealed that the Chornobyl nuclear accident and its consequences caused strong social and psychological stress among clean up workers 1986-1987. We have identified a set of factors closely related to the Chornobyl accident, they have caused a sustainable development of mental syndrome - «Anxiety about their own health and the health of family members, especially children¼. The other set of stressors which are not closely relat ed to the Chornobyl accident but are the result of the social and economic, social and political situation in the coun try. However the former was found to be the cause of such a psychological state as «dissatisfaction with the com pleteness and quality of life¼. CONCLUSIONS: Social and psychological state of the Chornobyl clean up workers 1986-1987 is estimated as «poor¼ and it integrally can be characterized as a state of chronic psychosocial stress. Mental syndrome «Anxiety about per sonal health and the health of family members¼ and psychological syndrome «Dissatisfaction with living condi tions¼ are main consequences of this state. We identified the main stressors closely related to the consequences of the Chornobyl accident as well as those that are not related to the accident but affect profoundly the level of men tal, social and physical well being. Results of the research are of great importance in organization and provision of social, medical and antiradiation protection of population under emergency situations involving radiation exposure. Key words: Chornobyl accident, clean up workers, social and psychological state, risk factors.