Accident Clean-up Workers Research Articles

Psychological distress 35 years after the Chornobyl accident in the Lithuanian clean-up workers

ABSTRACT The adverse effects on the health of the Chornobyl nuclear power plant accident clean-up workers have been reported previously. However, there is a lack of studies on the mental health of Chornobyl clean-up workers. The current study explored psychological distress in a sample of Lithuanian clean-up workers 35 years after the accident. In total, 107 Lithuanian Chornobyl clean-up workers (Mage = 62.5) and 107 controls were included in the study. The Hospital Anxiety and Depression Scale (HAD) was used for the assessment of anxiety and depression. The depression symptoms were significantly higher in the clean-up workers compared to the control group. The prevalence of severe depression symptoms was 23.4% and 4.7% in the Chornobyl clean-up workers and control groups, respectively. The risk for severe depression was associated with Chornobyl clean-up work (adjusted OR = 5.9). No differences in the anxiety symptoms were found between clean-up workers and controls. The study revealed the deteriorated mental health of the Lithuanian Chornobyl clean-up workers 35 years after the disaster – in particular, high levels of depression. Psychosocial support programmes for clean-up workers should be provided to mitigate the adverse effects of the disaster.

Radiation-associated cerebroophtalmic effects

IntroductionWe proposed to consider the brain and eye as a target of ionizing radiation exposure. Prevention of potential radiation-associated cerebroophtalmic effects are crucial for successful long-term space missions; interventional radiology; medical, occupational and accidental irradiationObjectivesDetermination of radiation-associated cerebroophtalmic effects in the long term after irradiation in adulthood and in utero.MethodsNeuropsychiatric, ophtalmological, neurophysiological and neuropsychological assessment of irradiated in adulthood (57 Chernobyl accident clean-up workers, liquidators), 52 persons exposed in utero as a result of the Chernobyl accident, comparison group (51 combatants of the Antiterrorist operation in Donbass), and 53 healthy people.ResultsRadiation-associated cerebroophthalmic pathology is characterized by high neuropsychiatric and ophthalmic comorbidity, which increases in proportion to the radiation dose, and is mainly represented by chronic vascular and degenerative diseases of the brain and retina, mild cognitive impairment (after irradiation in adulthood), as well as disorders of the autonomic nervous system; non-psychotic organic mental disorders; neurotic, stress-related and somatoform disorders; vascular and dystrophic processes in the retina (after in utero exposure). Characteristic of both radiological scenarios remains intellectual disharmony due to a decrease in the verbal IQ. The delay and attenuation of cerebral visual afferentation processing were observed in prenatally exposed.ConclusionsRadiation-associated cerebroophtalmic effects in the long term after irradiation in adulthood and in utero could be mainly classified as a “small vessel disease of the brain and eye” of vascular-degenerative nature and possible latent demyelination after irradiation in utero.DisclosureNo significant relationships.

LONG/TERM GENETIC AND EPIGENETIC DISORDERS IN PERSONS EXPOSED TO IONIZING RADIATION AND THEIR DESCENDANTS (review).

The review is devoted to long-term genetic and epigenetic disorders in exposed individuals and their descendants,namely to cytogenetic effects in the Chornobyl NPP accident clean-up workers and their children, DNA methylation as an epigenetic modification of human genome. Data presented in review expand the understanding of risk of the prolonged exposure for the present and future generations, which is one of key problems posed by fundamental radiation genetics and human radiobiology.

Solid cancer incidence risk in in the Ural cohort of the accidentally exposed population: 1956–2017

To date, the study of the effects of chronic exposure of the South Ural population has been carried out in two separate cohorts – in the Techa River Cohort and in the East Urals Radioactive Trace Cohort. In 2019, the Ural cohort of accidentally exposed population was formed. It included the population exposed in two radiation situations in the Southern Urals in the 1950s. The number of the combined cohort for the cancer incidence analysis was about 60 thousand people, the follow-up period was extended to 2017, the number of solid cancers was 4537, and the number of person-years was 1283267, which is 3 times more than when analyzing the effects of exposure in each of the two radiation situations separately. In the incidence analysis of all solid cancer types, we used the dose accumulated in the walls of the stomach, which corresponds to the dose accumulated in most organs and tissues with the exception of bone tissue and red bone marrow. The mean dose to the stomach accumulated over the entire follow-up period for cohort members was 38 mGy, the maximum -1.13 Gy. The paper presents the first results of solid cancer incidence risk analysis in the combined cohort, which show a statistically significant dose dependence of the incidence in case of chronic exposure in the range of low and medium doses. The sex and age-averaged excess relative risk value of 0.075/100 mGy (the 95% confidence interval is 0.039–0.113) is comparable to that obtained in the studies of the Japanese cohort of atomic bomb survivors. The statistically significant excess relative risk value of 0.047/100 mGy, obtained separately for men, is in good agreement with that in professional cohorts where men prevail – in the cohort of the Chernobyl NPP accident clean-up workers and in the cohort of professional workers in the three countries (UK, France, USA). The established cohort with a long follow-up period has a great potential for furthermore detailed studies of the effects of radiation and non-radiation factors on public health.

Construction of fluorescence in situ hybridization (FISH) translocation dose-response calibration curve with multiple donor data sets using R, based on ISO 20046:2019 recommendations

Purpose: Dose-response curve (DRC) generation is an important aspect in cytogenetic biodosimetry for accurate dose estimation for individuals suspected of prior irradiation. DRC construction with dicentric chromosomes after acute radiation is well-established following the publication of the IAEA EPR-Biodosimetry 2011 and ISO 19238:2014. However, the short half-life of dicentrics might not be suitable for retrospective dose estimation in radiation medical workers, radiation accident clean-up workers and the general public living in areas with higher than average amount of radiation. There is an urgent need for a chromosome translocation-based DRC, which is constructed based on translocation identification with fluorescence in situ hybridization (FISH). Despite several attempts to generate such a DRC in the past 40 years, no internationally standardized protocol has been developed until 2019, resulting in possible statistical uncertainties between DRCs previously generated.Materials and methods: Using the recently published ISO 20049:2019, a DRC from five healthy donors (four males: 23, 35, 44, 55 years old, one female: 33 years old) was generated with age-adjusted translocations scored per cell equivalent (age-adjusted Tr/CE), using a modified R-script previously published in EPR-Biodosimetry, for 60Co gamma-ray doses of 0, 0.01, 0.02, 0.05, 0.1, 0.2, 0.5 and 1 Gy. The translocation data set used, based on probes used for chromosomes number 1, 2, and 4, was previously published by Abe et al. in 2018.Results: The results output from R include the DRC coefficients (C, α, β), their p-values, the goodness-of-fit Pearson’s chi square value and its corresponding p-value, and the DRC with its 95% confidence interval (CI). The equation of the DRC obtained was 0.0005 (±0.0001) +0.0178 (±0.0037) D + 0.0901 (±0.0054) D2. DRC generated with averaged Tr/CE had a wider 95% CI than DRC generated with pooled Tr/CE, resulting in a 1.3–1.5 times increase in estimated dose range. No outliers between α coefficients from previously published modified DRCs and our DRC were detected with robust Z-score.Conclusions: ISO 20046:2019 should be referenced for future FISH translocation-based DRC generation to ensure statistical reliability of dose estimation. Important considerations for FISH translocation-based DRC up to 1 Gy include scoring more than 2000 CE per dose, the use of multiple donors, age-adjustment of observed translocations, the use of a minimum of 5 dose points including 0 Gy, scoring of total simple translocations in only stable cells and the decision of using pooled or averaged age-adjusted Tr/CE.

Cardiovascular complications in metabolic syndrome in the Chernobyl NPP accident clean-up workers of in a late period upon exposure to ionizing radiation

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

DISEASES OF CIRCULATORY SYSTEM AND COMORBID TYPE II DIABETES MELLITUS IN THE CHORNOBYL ACCIDENT CONSEQUENCES CLEAN-UP WORKERS.

The study was focused on evaluation of peculiarities of the clinical manifestations of type II diabetesmellitus (TIIDM) in the Chornobyl nuclear power plant (ChNPP) accident clean-up workers (ACUW). The ChNPP ACUW of 1986-1987 period (n = 449, males) and 158 males not exposed to ion-izing radiation (the control group, CG) were involved in the study in 2013-2018. Diagnosis of cardiovascular disease(CVD) and type II diabetes mellitus (TIIDM) was established in accordance with diagnostic standards adopted inUkraine. All study subjects had no signs of CVD, and neither of endocrine disease nor of metabolic disorders beforethe accident. Clinical course of the TIIDM, depending on the disease severity, onset of angiopathy and polyneuropathy,prevalence of angina pectoris and heart failure were surveyed and analyzed. Concomitant TIIDM was associated witha higher incidence of angina pectoris and heart failure. According to the Kaplan-Meier method of survival estimatingthe accumulation of new TIIDM cases occurred faster in the ACUW compared with individuals in the CG, however withno statistical significance in subjects aged up to 60 years old (log-rank test χ2 = 4.89, p = 0.027). Mean age of theACUW having comorbid CVD and DM was (54.6 ± 9.7) years, whilst in the CG it was (59.9 ± 10.7) years (p = 0.005). The DM course in the ACUW was not significantly different from non-irradiated control both in sever-ity and such complications as angiopathy of retina and lower extremities, as well as manifestations of lower extrem-ity polyneuropathy. Clinical manifestations of CVD in the form of angina pectoris and heart failure were identical inthe ACUW and control group of patients having a comorbid TIIDM. The latter was a factor exacerbating the CVDcourse and leading to a higher prevalence of angina pectoris and heart failure both in the ACUW and in non-irritat-ed individuals. Accumulation of the new DM cases occurred more rapidly in ACUW vs. non-irradiated control, so theywere in average 5 years younger at the time of TIIDM manifestation than the control subjects.

GENDER DISPARITIES OF CIRCULATORY DISEASE PROGRESS IN THE CHORNOBYL ACCIDENT CLEAN-UP WORKERS AND PHOSPHODIESTERASE 4D GENE rs966221 POLYMORPHISM.

Evaluation of the hypertensive disease (HD) and coronary heart disease (CHD) progress in the ChornobylNPP (ChNPP) accident clean-up workers (ACUW) and persons not exposed to ionizing radiation depending on gen-der and genotype of the phosphodiesterase 4D (PDE4D) gene rs966221 polymorphism. There were male ACUW (ACUWm; n=515) and female ACUW (ACUWf; n=145) involved in thestudy since 2013 till 2018. Participation in the clean-up works took place in 1986-1987. The control group includ-ed male (CGm; n=162) and female (CGf; n=120) persons not exposed to ionizing radiation. All study subjects havehad neither signs nor symptoms of HD or CHD before the ChNPP accident. Review of the Kaplan-Meier survival tables indicated that according to median survival the HD emerged inACUWm and ACUWf in a younger age (47.5 ± 0.6 and 50.7 ± 0.7 years old, respectively) vs. CGm or CGf (54.9 ± 1.1 and54.4 ± 1.1 years, respectively). The same was true for CHD where the median values were (56.8 ± 0.5), (61.2 ± 0.8),(61.6 ± 1.0) and (64.2 ± 1.4) years respectively. Review of cumulative incidence of HD and CHD revealed no associ-ation of the PDE4D gene rs966221 polymorphism with the diseases of concern. The TT gene carrier state comparedto the CC or CT genes features an increased risk of myocardial infarction (MI) 2.9 times in ACUWm, 4-fold in CGm, and5.5 times in CGf (p < 0.05). No any gene carrier state was associated with MI in the ACUWf. Onset of menopause wasfollowed by an increase in HD incidence vs. males. The male and female ChNPP ACUW were developing HD and CAD at a younger age compared with cor-responding non-irradiated control. In male ACUW in comparison with female ACUW the cumulative morbidity ratefor MI was higher in any age range, whereas for CAD it was higher from 23 to 74 years, and for HD from 25 to 53 yearsof age. In male and female ACUW as well as in non-irradiated control the HD developed much earlier than CHD. Thecarrier state of TT genotype of PDE4D gene rs966221 polymorphism increases the risk of MI in males of all ages, inthe non-irradiated controls it is increased in 65 years for men and in 60 years for women. No data on association ofthe genotype of the described gene polymorphism with MI were found in female ACUW.

MORPHOLOGICAL AND FUNCTIONAL MYOCARDIAL ABNORMALITIES IN THE CHORNOBYL NPP ACCIDENT CLEAN-UP WORKERS OF «IODINE» PERIOD HAVING GOT TYPE 2 DIABETES MELLITUS.

Evaluation of morphological and functional myocardial abnormalities in the Chornobyl NPP (ChNPP)accident clean-up workers (ACUW) of the «iodine» period exposed to ionizing radiation at a young age and havinggot the type 2 diabetes mellitus (T2DM). The ChNPP ACUW of «iodine» period (n=111) exposed to ionizing radiation (IR) at a young age(18-35 years) were involved in the study. Subjects having got the T2DM were included in study Group I (n = 66), per-sons with normal glucose challenge test were selected as a comparison Group II (n = 45). External radiation doses (ERD)ranged from 10 to 860 mSv. The Group III (clinical control) included persons having got the T2DM with no radiationexposure in a history (n=20). Group IV was the normative one. There was no statistical difference between the groups inage, sociodemographic characteristics and level of education. Echocardiography and cardiac Doppler sonography wereperformed in one- and two-dimensional regimens according to the recommendations of the European Association ofEchocardiography. Total adiponectin and proinflammatory cytokine (TNF-α and IL-6) concentrations were assayed by theimmunoenzyme method. Statistical processing of data was carried out using the Microsoft® Exel 2002 software. Myocardial remodeling in the ChNPP ACUW of a «iodine» period having the T2DM occurred through a sig-nificant increase of its linear parameters. Volumetric parameters (EDV, ESV and their indexes) were within maximumpermissible limits significantly exceeding however the values in the Group IV. There was aт increase in myocardialmass of the left ventricle and its indices with the formation of structural-geometric abnormalities, mainly in theform of concentric hypertrophy with a decrease in the myocardial contractile capacity. There was no differences ofthe vast majority of key morphometric parameters of myocardium in the dose subgroups, while in persons with ERD> 500 mSv the incidence of serious left ventricular hypertrophy (LVMMI > 149 g/m2) significantly exceeded thisvalue in individuals with lower ERD. At a maximum ERD the more intense fibroplastic processes were observed inmyocardium [a significant increase in the interstitial collagen volumetric fraction (ICVF)] as compared to the caseswith ERD up to 50 mSv. Intensification of myocardial fibroblastic processes occurred in the comparizin group andgroup off clinical control. In combination with concentric myocardial hypertrophy this may lead to an increased riskof cardiovascular complications. Strong negative correlation was revealed between the parameters of left ventricu-lar structure in diastole and adiponectin level in the ChNPP ACUW of a «iodine» period with diagnosed T2DM, high-lighting its cardioprotective effect. At the same time, the content of FNP-α and IL-6 proinflammatory cytokines hada positive correlation with the main parameters of abnormal myocardial remodeling, indicating the possibility oftheir role in unfavorable cardiovascular modifications. The decreased adiponectin level and elevated levels of TNF-α and IL-6 in the ChNPP ACUW of a«iodine» period having got the T2DM are the meaningful factors in progression of LV geometric remodeling. Togetherwith fibroplastic processes (a significant increase in ICVF) this may be a basis for the development of myocardialremodeling processes, namely a concentric hypertrophy, which is a prerequisite for the development of complica-tions in cardiovascular system.

CLINICAL, HEMATOLOGICAL CHARACTERIZATION AND POLYMORPHISM OF ABO AND Rh BLOOD GROUP SYSTEMS IN PLASMA CELL MYELOMA PATIENTS.

Peculiarities of the disease natural history were reviewed in the 111 plasma cell myeloma(PCM) patients receiving medical management at the Department of Radiation Oncohematology of the NRCRM dur-ing 2010-2017. Principal clinical and laboratory characteristics of PCM, namely the values/levels of LDH, β2-mic-roglobulin, albumin, serum calcium, urea, creatinine and hemoglobin were assessed, taking into account the gender,radiation history (ChNPP accident clean-up workers, evacuees from areas of obligatory resettlement, inhabitants ofcontaminated territories, and the comparison group) and the PCM stage codenamed by Durie-Salmon et al. (1975)and the ISS (1985) classifications. Distribution of polymorphic variants on ABO and Rh blood systems was studiedin the 106 PCM patients. It was found that the level of β2-micro-globulin and calcium was increased significantly in male (p = 0.02and p = 0.04, respectively), whereas serum urea content was elevated in female (p = 0.04) PCM patients featuring acompromised radiation anamnesis in comparison to non-irradiated patients. Some probable differences were foundfor urea level (F = 3.58, p = 0.05) and serum albumin (F = 4.00, p = 0.05) in the examined group of PCM patients.Probable (p < 0.05) incidence increase of the B phenotype was established as a predictor of complicated natural his-tory of PCM with abnormal genetic equilibrium resulted from the increased incidence of IB allele in chronic renal fail-ure (CRF) patients. Significant (p < 0.05) prolongation of the remission period upon a standard PCT application wasfound in PCM patients being the A phenotype carriers having a preserved gene and phenotypic equilibrium comparedwith carriers of O and B phenotypes. Clinical and hematological parameters are different in PCM patients survived after the ChNPP accidentand those with favorable radiation history. Distribution of polymorphic variants of ABO antigenic structures inpatients with complicated natural history of the disease is also different, that can be a background for predictingthe effectiveness of treatment. Further research is required in this field.

Serum content of total adipionectin in the ChNPP accident clean/up workers of the «iodine period» suffering from type 2 diabetes mellitus (literature review and research data)

assay of the total adiponectin level in the ChNPP accident clean up workers (ACUW) of the «iodine peri od» exposed to ionizing radiation in a young age and suffering now from type 2 diabetes mellitusMaterials and methods. The Chernobyl Nuclear Power Plant accident clean up workers (ACUW) of the iodine period (n=111) exposed to ionizing radiation at a young age (18-35 years) were examined in two groups: Group I (main study group, n=66) of persons with type 2 diabetes mellitus (DM) and Group II (comparison group, n=45) of persons with normal glucose challenge test results. Total radiation doses varied in the range of 10.0-860.0 mSv. Group III (nosological control group, n=20) included persons suffering type 2 DM but not exposed to ionizing radiation (IR) and Group IV were apparently healthy. All study groups were representative by the age. Anthropometric data and parameters of glycemic control were assayed. Index of the homeostatic model for assessing insulin resistance (HOMA IR) was calculated. Level of total adiponectin was assayed by the immune enzyme method. Statistical pro cessing of the data was carried out using Missrosoft® Exxel 2002 software. Serum concentration of total adiponectin in the Chornobyl NPP ACUW of the iodine peri od and suffering type 2 DM despite having normal body weight or overweight or any degree of obesity was signifi cantly lower compared to apparently healthy persons ACUW with and normal glycemic control. Moderate negative correlation was found between the level of total adiponectin and degree of obesity in the ACUW suffering type 2 DM (t = 0.367, p <0.05). With an increase in the duration of the disease there was a decrease in serum concentration of total adiponectin in the Chornobyl NPP ACUW of iodine period suffering type 2 DM and in the group of nosologi cal control. The most favorable type of glycemic profile was peculiar for patients in the main group with higher lev els of total serum adiponectin and the lowest body mass index (up to 25 kg/m2). An increase in the body mass index was accompanied by an adverse combination of abnormalities in glycemic metabolism (increased glucose concen tration, IRI, and HbA1c), insulin resistance (a significant increase in HOMA) against the background of a decrease in concentration of total adiponectin. No significant differences were found in adiponectin levels in dose subgroups. At the same time, the reliable differences between the main group and comparison group were found in the 2-5th dose subgroups, which are due to differences in numbers of people with metabolic syndrome (obesity) in the groups.

Pilot study of parathyroid glands in adult and pediatric subjects exposed to ionizing radiation after the ChNPP accident, methodology of parathyroid diagnostic ultrasound

Estimation of the parathyroid hyperplasia prevalence after the ChNPP accident in adults exposed to ion izing radiation and their descendants using the diagnostic ultrasound and its methodology elaboration. The pilot prospective study of the prevalence of parathyroid hyperplasia among the Chornobyl Nuclear Power Plant (ChNPP) accident adult survivors (n=686) and their descendants (54 children) was performed using diagnostic ultrasound examination of thyroid and parathyroids. Among the study subjects there were 339 ChNPP accident clean up workers (ACUW), 32 persons were evacuated from the 30 km exclusion zone and 224 ones were included to the control group. Diagnostic ultrasound of thyroid and parathyroids was performed according to the standard method. Additionally, in children with parathyroid hyperplasia an additional assay of 25 hydroxyvitamin D levels in serum was performed. In calculating the statistical significance, its level p < 0.05 was considered statistically significant. Parathyroids are a few small but critically important endocrine glands that synthesize parathyroid hormone, regulating mainly phosphoric calcium metabolism. Insufficient (hypoparathyroidism) or excessive (hyperparathy roidism) function of parathyroids is harmful to the patients affecting the state of nervous and cardiovascular sys tem. Parathyroidss can accumulate isotopes of cesium, strontium and radioactive iodine. The available data testify to an increased incidence of clinically significant hyperplasia of parthyroids (more than 9 mm in adults and more than 5 mm in children) among persons exposed toionizng radiation as a result of the accident at the ChNPP (28.64%) and their descendants (23.8-70.6%). First of all are concerned those adults who live in contaminated areas in comparison with the control group (24.15% in not irradiated). Evacuees from the 30 km exclusion zone being the category of people who were exposed to the absorbed iodine isotopes in the first days of the Chernobyl accident are the another risk group. These data demonstrate sensitivity of parathyroidss to the impact of incorpo rated isotopes (iodine, cesium and strontium), which in the long term exposure create conditions for structural and functional changes in regulation of phosphorous calcium metabolism being the basis for a significant prevalence of osteopenia and osteoporosis in irradiated individuals and their descendants. A number of further studies are required to clarify the findings and to disclose the hormonal mechanisms of radiation effects on parathyroids. Parathyroid glands are radiosensitive and susceptible to effects of strontium, cesium and iodine iso topes, which cause parathyroid irradiation and subsequent structural and functional changes, being a prerequisite for development of osteopenia and osteoporosis in the ChNPP accident survivors and their descendants. High inci dence of parathyroid hypertrophy is found in the inhabitants of the radiation contaminated territories (long term irradiation by cesium isotopes), as well as in evacuated from the 30 km exclusion zone (irradiation by iodine iso topes in the early days of the accident).

Psychophysiological characteristics in the ChNPP accident clean-up workers, exclusion zone evacuees and anti-terrorist operation servicemen

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. 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). 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. 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.

福島第一原子力発電所における事故収束作業員の熱中症発生に関する特徴

Ever since the Fukushima Daiichi nuclear power plant (NPP) accident, every day about 3,000 workers have been working to repair the situation. The frequent occurrence of heat disorders has been a concern for the workers wearing protective clothing with poor ventilation. We have been analyzing the heat disorder problem since the accident in order to come up with a solution to prevent future heat disorder incidents among Fukushima Daiichi NPP accident clean-up workers. From March 22 to September 16, 2011, the Fukushima Labor Bureau assessed 43 cases of nuclear power plant workers with heat disorders. Age of subject, month and time of occurrence, temperature, and humidity were examined for each case, as well as the severity of heat disorders. The grade of severity was divided into Grade I and Grade II or higher. Then, age, temperature, and humidity were analyzed using the Mann-Whitney Utest, and age, temperature, humidity, and presence or absence of a cool-vest were analyzed using the χ(2) test and logistic regression analysis. SPSS version 17.0 statistical software was used with a level of significance of p< 0.05. Heat disorders occurred most frequently in subjects in their 40s (30.2%), followed by those in their 30s (25.6%), mostly in July (46.5%) between 7 am and 12 pm (69.8%). Heat disorders occurred most frequently in environments with temperatures more than 25°C (76.7%) and humidity of 70-80% (39.5%). Heat disorders of Grade II or higher occurred in 10 cases, 5 of which were in June. According to statistical analysis, there were no significant differences in difference of severity for all factors. Heat disorders usually occur in workers aged 45-60; however, cases of heat disorders at the Fukushima Daiichi NPP occurred in clean-up workers at the relatively younger ages of 30-40, suggesting the need for heat disorder prevention measures for these younger workers. Heat disorder cases primarily occurred in the morning, necessitating preventive measures for the early hours of the day. In addition, because heat disorders of Grade II or higher occurred in June in 5 of 10 cases, we believe heat disorder precautions should be implemented from June. The lack of significant difference in severity difference may be attributable to the small number of cases or other factors. We think Fukushima Daiichi NPP accident clean-up workers need heat disorder prevention measures for their safety, based on the results of this study.

P2-150 Results of the 22-years study of leukaemia in Chernobyl accident clean-up workers in Ukraine

IntroductionThe study was conducted to determine whether the leukaemia incidence rate in Chernobyl Nuclear Power Plant catastrophe clean-up workers depended on the year of the emergency work and the period...

The correlation between molecular cellular parameters and immune status in the blood lymphocytes of chernobyl nuclear accident cleanup workers

Genome damage, namely, the frequency of cells with micronuclei (MN) and chromosome aberrations, the level of DNA double-strand breaks, and concentration of reactive oxygen species (ROS), as well as 28 immunological characteristics were studied in the blood lymphocytes of Chernobyl nuclear accident cleanup workers. The goal of the work was to examine the cytogenetic and molecular biological changes in the blood lymphocytes of exposed individuals 24 years after the accident and to find the correlations between genome damage and immunity parameters. The rate of cells with MN and the total rate of the cells with all types of chromosome aberrations did not differ from those of unexposed individuals; however, the amount of chromosome type aberrations and DNA double-strand breaks were elevated in the lymphocytes of cleanup workers, whereas the concentration of reactive oxygen species was decreased. As compared with the control population cohort, cleanup workers displayed a statistically significant increase in the percent of cytotoxic CD8+ T lymphocytes, CD16+ natural killers, CD3+CD16+CD56+ natural killer cells (NK-T cells, displaying antiviral and antitumor activities), HLA-DR+ (a marker of late lymphocyte activation), and regulatory T lymphocytes (CD4+CD25+high). The level of serum immunoglobulin (IgA) increased in a statistically significant manner. The index of immune regulation decreased along with the values of phagocytic activities of neutrophils (PAN) and macrophages (PAM). Liquidators displayed statistically significant (p < 0.05) correlations of the rate of cells with MN with the content of regulatory T lymphocytes (CD4+CD25+high) and between the reactive oxygen species concentration and the content of activated T lymphocytes. A considerably larger number of correlations was detectable at the level of sufficiently reliable trends at p < 0.10, in particular, of the rates of chromosome aberrations and DNA double-strand breaks with the contents of natural killers and regulatory T lymphocytes, as well as of the rates of the cells containing MN and DNA DSBs with PAN. This suggests that the genomic instability induced by exposure 24 years ago during the cleanup activities after the Chernobyl nuclear accident is manifested now as an increased level of genome damage and a decrease in oxidative status, which can result in the cell and humoral immunity disturbance.

Changes in the Nervous System in Chernobyl Nuclear Power Plant Accident Clean-Up Workers

Changes in the Nervous System in Chernobyl Nuclear Power Plant Accident Clean-Up Workers

Clinical aspects of the health disturbances in Chernobyl Nuclear Power Plant accident clean-up workers (liquidators) from Latvia

The health status of some 6,000 workers from Latvia who went to clean-up the Chernobyl Nuclear Power Plant (CNPP) site following the explosion on 26 April 1986 has been analyzed. The data on these workers have been recorded in the Latvian State Register of Occupational disease patients and people exposed to ionizing radiation due to Chernobyl NPP accident (Latvian State Register) that was established in 1994. From these data, estimates have been made of external ionizing radiation to which these workers were exposed together with observations on the impact of exposure to heavy metals (especially lead and zinc) and radioactive isotopes released during the reactor 'meltdown'. These factors along with psycho-emotional and social-economic stresses account for a marked excess of mortality and morbidity in the group of CNPP accident clean-up workers compared with that of the non-exposed normal Latvian population adjusted for age and sex. The number of diseases or conditions in the CNPP accident clean-up workers has progressively risen from an average of 1.3 in 1986 to 10.9 in 2007. This exceeds for the Latvian population when adjusted for age and sex. The most serious conditions affect the nervous, digestive, respiratory, cardiovascular, endocrine (especially thyroid) and immunological systems. While the morbidity associated with diseases of the respiratory and digestive systems has decreased in recent years that in the other systems is increasing. In recent years, there has been an increased occurrence of cancers affecting the thyroid, prostate and stomach. Clinical and laboratory investigations suggest that surviving CNPP accident clean-up workers exhibit signs of immuno-inflammatory reactions causing premature aging with evidence of autoimmune diseases and immunological deficiencies or abnormalities. It is suggested that the CNPP accident clean-up workers may have a specific syndrome, the 'Chernobyl post-radiation neurosomatic polypathy', due to sustained oxidant stress injury, as a result of exposure to radiation and lead.

Mini-and microsatellite mutations in children from Chernobyl accident cleanup workers

Knowledge about possible genotoxic effects of low-dose radiation on the human germline is limited and relies primarily on extrapolations from high-dose exposures. To test whether ionizing radiation can cause paternal genetic mutations that are transmitted to offspring, we enrolled families of 88 Chernobyl cleanup workers exposed to ionizing radiation. We analyzed DNA isolated from lymphocytes for mutations via DNA blotting with the multi-locus minisatellite probes 33.6 and 33.15 and via PCR in a panel of six tetranucleotide repeats. Children conceived before and children conceived after their father’s exposure showed no statistically significant differences in mutation frequencies. We saw an increase in germline microsatellite mutations after radiation exposure that was not statistically significant. We found no dependence of mutation rate on increasing exposure. A novel finding was that the tetranucleotide marker D7S1482 demonstrated germline hypermutability. In conclusion, our results do not support an increased level of germline minisatellite mutations but suggest a modest increase in germline mutations in tetranucleotide repeats. Small sample size, however, limited statistical power.

The distribution of chromosome damage, non-reciprocal translocations and clonal aberrations in lymphocytes from Chernobyl clean-up workers

In this paper we determined whether the frequencies of translocations and insertions are proportional to chromosome size in peripheral blood lymphocytes from Chernobyl nuclear accident clean-up workers and healthy unexposed control subjects. The frequency of aberrations among chromosomes 1, 2 and 4 in both groups was found to be significantly different from the distribution expected on the basis of chromosome size, although the difference was only marginally significant in controls. We also determined whether differences exist in aberration frequencies measured by two scoring systems: the classical method, where reciprocal exchanges are scored as one event, and PAINT, where each break junction is scored as a single event. The two scoring systems gave highly correlated results which yielded an interpretable arithmetic relationship between frequency measurements using the two systems. Approximately 34% of all translocations were observed to be non-reciprocal, and cells bearing clones of abnormal cells were observed in 6 of 198 subjects (3.0%). Our results demonstrate that clones of abnormal cells and the presence of non-reciprocal translocations contribute to the non-proportional distribution of radiation-induced and spontaneous cytogenetic damage.