ABSTRACT
OBJECTIVE: to study the clinical and neurophysiological features in the Chornobyl clean-up workers with a verified chronic cerebrovascular disease/cerebral small vessels disease (SVD) exposed to low doses of ionizing radiation (IR), employees of the Chornobyl Nuclear Power Plant (SSE ChNPP), who were exposed to the stress factor of a full-scale war as a result of being held captive by the Russian military at their workplaces, and individuals of the non-irradiated comparison group.Design, object and methods. A cross-sectional clinical study with parallel external control groups. We studied and carried out an expert statistical analysis of the clinical and neurophysiological characteristics of 62 male subjects, from which three examination groups were formed: 1) a randomized sample from the Clinical Epidemiological Register (CER) of the State Institution «National Research Center for Radiation Medicine of the National Academy of Medical Sciences of Ukraine¼ (NRCRM) of 22 Chornobyl clean-up workers ('Chornobyl liquidators') in 1986-1990,examined during 2020-2021, aged 50-68 years at the time of examination (M ± SD: (58.1 ± 5.2) years) with a documented external radiation dose of 0.03-2.30 Sv; 2) 24 SSE ChNPP employees exposed to the stress factor impact of a full-scale war as a result of being held captive by the Russian military at their workplaces. The average age of the examined was (54.5 ± 5.8) years (range 46-71 years). 3) Comparison group - 16 non-exposed men with verified chronic cerebrovascular disease/cerebral small vessels disease (SVD). The average age of the examined was (57.8 ± 5.6) years (range 50-70 years). RESULTS: Neurophysiological studies confirm the presence of the pronounced dysfunction of the cortico-limbic system of the left dominant hemisphere of the brain with special involvement of the hippocampus in the Chornobyl clean-up workers. In the SSE ChNPP group, for the first time, the disorders of cerebral neurodynamics were detected in the form of functional hypofrontality and hyperfunction of the cortico-limbic system with lateralization to the right hemisphere. CONCLUSIONS: Today there exists a long-term thorough methodological and evidence base for a possible neurophysiological diagnosis and differential diagnosis of the combined cerebral effects of IR and psycho-emotional stress associated with the conditions of military conflicts. Neurophysiological technologies can be used in the objective professional and qualification selection of employees in a number of professions that require quick and responsible decision-making. Employees of SSE ChNPP need further medical and psychological support due to an increased risk of developing mental health disorders.
Subject(s)
Cerebrovascular Disorders , Chernobyl Nuclear Accident , Radiation Exposure , Male , Humans , Middle Aged , Aged , Cross-Sectional Studies , Radiation Exposure/adverse effects , Radiation, Ionizing , Cerebrovascular Disorders/etiology , Ukraine/epidemiology , Radiation DosageABSTRACT
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.
Subject(s)
Brain/radiation effects , Cosmic Radiation/adverse effects , Eye/radiation effects , Prenatal Exposure Delayed Effects , Radiation Injuries/etiology , Radiation, Ionizing , Space Flight , Adolescent , Adult , Astronauts/statistics & numerical data , Child , Child, Preschool , Eye/physiopathology , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Pregnancy , Radiation Dosage , Radiation Injuries/physiopathology , Radiologists/statistics & numerical data , Young AdultABSTRACT
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.
Subject(s)
Abnormalities, Radiation-Induced/physiopathology , Chernobyl Nuclear Accident , Evoked Potentials, Visual/radiation effects , Prenatal Exposure Delayed Effects/physiopathology , Radiation, Ionizing , Retina/anatomy & histology , Retina/radiation effects , Adult , Brain Diseases/physiopathology , Eye Diseases/physiopathology , Female , Humans , Male , Pregnancy , Ukraine , Young AdultABSTRACT
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).
Subject(s)
Brain Injuries/pathology , Brain/radiation effects , Chernobyl Nuclear Accident , Emergency Responders , Eye Injuries/pathology , Eye/radiation effects , Radiation Injuries/pathology , Brain/pathology , Brain Injuries/epidemiology , Brain Injuries/etiology , Dose-Response Relationship, Radiation , Eye/pathology , Eye Injuries/epidemiology , Eye Injuries/etiology , Humans , Radiation Dosage , Radiation Exposure/adverse effects , Radiation Injuries/epidemiology , Radiation Injuries/etiology , Radiation, Ionizing , Time Factors , Ukraine/epidemiologyABSTRACT
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 (LÐ/S, LÐ/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 LÐ/ LÐ.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.
