Background: Although childhood exposure to radioactive iodine-131 (I-131) is an established risk factor for thyroid cancer, evidence for an association with thyroid nodules is less clear. The objective of this study is to evaluate the association between childhood I-131 exposure and prevalence of ultrasound-detected thyroid nodules overall and by nodule histology/cytology (neoplastic/suspicious/non-neoplastic), size (<10 mm/≥10 mm), and number (single/multiple). Methods: This is a cross-sectional study of radiation dose (mean = 0.53 gray, range: 0.0003-31 gray) and screen-detected thyroid nodules conducted in 1998-2000 (median population age 21.5 years) in a cohort of 13,243 residents of Ukraine who were under 18 years at the time of the Chornobyl accident on April 26, 1986. Excess odds ratios per gray (excess odds ratio [EOR]/Gy) and confidence intervals (CIs) were estimated using logistic regression. Results: Among 13,078 eligible individuals, we identified 358 (2.7%) with at least one thyroid nodule. Significantly increased dose-response associations were found for all nodules and nodule groups with doses <5 Gy except individuals with non-neoplastic nodules. Among individuals with doses <5 Gy, the EOR/Gy for neoplastic nodules (5.35; CI: 2.19-15.5) was significantly higher than for non-neoplastic nodules (0.24; CI: 0.07-0.74), but the EOR/Gy did not vary by nodule size or number. Conclusions: Childhood exposure to I-131 is associated with an increased risk of thyroid nodules detected 12-14 years following exposure, and the risk for neoplastic nodules is higher than for non-neoplastic nodules. Analyses of incident thyroid nodules may help clarify dose-response patterns by nodule characteristics and provide insights into thyroid nodule etiology.

The aim of this study was to assess the exposures received by firefighters engaged in extinguishing the large-scale wildfires in the most contaminated areas of the Ukrainian part of the Chornobyl Exclusion Zone in 2016 and 2020. The assessments are based on measurements of radionuclide airborne concentrations in the breathing zones of workers and at the aerosol sampling stations of the automated radiation monitoring system operated by SSE Ecocenter. During the wildfires, the radionuclide airborne concentrations increased by orders of magnitude compared to the background levels, reaching maximum values in the firefighting area of 1.20 ± 0.01 Bq m-3 for 90Sr, 0.18 ± 0.01 Bq m-3 for 137Cs, (1.8 ± 0.3) ∙10-4 Bq m-3 for 238Pu, (4.5 ± 0.7) ∙10-4 Bq m-3 for 239-240Pu, and (8.0 ± 1.3) ∙10-3 Bq m-3 for 241Pu. The internal effective doses to firefighters due to inhaled radionuclides did not exceed 2 μSv h-1 and were 3-5 times lower compared to the external dose of gamma radiation. Thus, the time of firefighting in the ChEZ will be limited by the external dose.

The 1986 disaster at the Chornobyl Nuclear Power Plant transformed the surrounding region into the most radioactive landscape known on the planet. Whether or not this sudden environmental shift selected for species, or even individuals within a species, that are naturally more resistant to mutagen exposure remains an open question. In this study, we collected, cultured, and cryopreserved 298 wild nematode isolates from areas varying in radioactivity within the Chornobyl Exclusion Zone. We sequenced and assembled genomes de novo for 20 Oscheius tipulae strains, analyzed their genomes for evidence of recent mutation acquisition in the field, and observed no evidence of an association between mutation and radioactivity at the sites of collection. Multigenerational exposure of each of these strains to several chemical mutagens in the lab revealed that strains vary heritably in tolerance to each mutagen, but mutagen tolerance cannot be predicted based on the radiation levels at collection sites, and Chornobyl isolates were not systematically more resistant than strains from undisturbed habitats. In sum, the absence of mutational signatures does not reflect unique capacity for tolerating DNA damage.

OBJECTIVE: to evaluate the subpopulation structure of peripheral blood leukocytes as a component of inflammaging in the servicemen of the Armed Forces of Ukraine and clean-up workers of the accident at the Chornobyl nuclear power plant.
METHODS: Three hundred ninety-seven males aged 30-82 (54.99 ± 8.85) years examined. Among them: clean-up workers of the accident at the Chornobyl nuclear power plant, aged 54-64 (59.95 ± 1.88) years, who were examined before the beginning and during the Russian military invasion of Ukraine; 24 civilians of the control group, aged 50-77 (58.87 ± 7.18) years and 15 persons of the age control group, aged 42-49 (46.00 ± 2.26) years, who examined before the war has started; the comparison group-W - 27 civilians (age: 51-82 (65.44 ± 9.13)) and the age control group-W - 14 civilians (age: 31-49 (40.64 ± 5.59)) who examined after the war has started; 73 servicemen of the Armed Forces of Ukraine aged 30-49 (42.20 ± 5.35) years and 54 servicemen aged 50-59 (54.07 ± 2.86) years. The subpopulation distribution of peripheral blood leukocytes was analyzed using flow cytometry.
RESULTS: A decrease in the relative number of CD45+ 14- granulocytes, CD3+ HLA-DR+ T-lymphocytes, and CD3-57+ NK against the background of an increase in the number of CD45+ 14+ monocytes, CD3-HLA-DR+ B-lymphocytes found in the majority of people in the examination groups, the study of which conducted after the beginning of the war, CD4+ T-lymphocytes and CD3+ 57+ NKT. The relative number of CD45+ 14- granulocytes increased against the background of a decrease in CD45+ 14- lymphocytes was noted in clean-up workers who were examined before the war started.About 30% of civilians over 50 years of age who were examined before the war started had a decrease in CD19+ B- lymphocytes, CD4+ and CD8+ T-lymphocytes, CD3-57+ NK, CD3+ 57+ NKT, and the CD4+ / CD8+ ratio. Conducted correlation analysis revealed a weak to moderate inverse correlation between the relative number of CD19+ B-lymphocytes and age in civilians, regardless of when they were examined, and the servicemen of the Armed Forces of Ukraine.Inverse correlations of HLA-DR+ B-lymphocytes, CD45+ 14+ monocytes, CD4+ T-lymphocytes, CD4+ / CD8+ ratio, and CD3-57+ NK and CD3+ 57+ NKT with age were noted in civilians who were examined after the war has started. A direct correlation between CD3+ 57+ NKT and age was found in the servicemen of the Armed Forces of Ukraine.
CONCLUSIONS: The immunological profile of both clean-up workers in the Chornobyl nuclear power plant and the servicemen of the Armed Forces of Ukraine or civilians was similar compared to the group with reference indicators. Anintergroup study revealed changes in the subpopulation distribution of peripheral blood leukocytes, which may be associated with both aging and changes in living conditions during military operations. Specific changes in cellular immunity can either tip the balance towards inflammaging or indicate already existing immunopathologicalreactions.
Мета: оцінити субпопуляційну структуру лейкоцитів периферичної крові як складової інфламейджингу у військовослужбовців ЗСУ та учасників ліквідації наслідків аварії на ЧАЕС.Матеріали і методи. Обстежено 397 чоловіків віком 30–82 (54,99 ± 8,85) років. Серед них: 190 учасників ліквідації наслідків аварії (ЛНА) на ЧАЕС, віком 54–64 (59,95 ± 1,88) років, які проходили обстеження до початку і під час повномасштабного російського вторгнення; 24 цивільні особи контрольної групи, віком 50–77 (58,87 ± 7,18) років і 15 осіб групи вікового контролю, віком 42–49 (46,00 ± 2,26) років, які проходили обстеження до початку війни; група порівняння–W – 27 цивільних осіб віком 51–82 (65,44 ± 9,13) років і група вікового контролю–W – 14 цивільних осіб віком 31–49 (40,64 ± 5,59) років), які проходили обстеження після початку війни; 73 військовослужбовці ЗСУ віком 30–49 (42,20 ± 5,35) років і 54 військовослужбовці ЗСУ віком 50–59 (54,07 ± 2,86) років. Аналіз субпопуляційного розподілу лейкоцитів периферичної крові проводили з використанням проточної цитометрії.Результати. У більшості осіб груп обстеження, дослідження яких проводилося після початку війни, виявлено зниження відносної кількості CD45+ 14- гранулоцитів, CD3+ HLA-DR+ Т-лімфоцитів, СD3-57+ НК на фоні підвищення числа CD45+ 14+ моноцитів, CD3-HLA-DR+ В-лімфоцитів, CD4+ Т-лімфоцитів і СD3+ 57+ НКТ. Підвищення відносної кількості CD45+ 14- гранулоцитів на фоні зниження CD45+ 14- лімфоцитів відмічене в учасників ЛНА на ЧАЕС, які пройшли обстеження до війни. Близько 30 % цивільних осіб, старше 50 років, які проходили обстеження до війни, мали зниження кількості CD19+ В-лімфоцитів, CD4+ та CD8+ Т-лімфоцитів, СD3-57+ НК, СD3+ 57+ НКТ і показника імунорегуляторного коефіцієнту CD4+ / CD8+. Проведений кореляційний аналіз виявив зворотну кореляцію слабкої та середньої сили між відносною кількістю CD19+ В-лімфоцитів і віком у цивільних осіб, незалежно від того, коли вони проходили обстеження, та військовослужбовців ЗСУ. Зворотні кореляційні зв’язки HLA-DR+ В-лімфоцитів, CD45+ 14+ моноцитів, CD4+ Т-лімфоцитів, імунорегуляторного коефіцієнта CD4+ / CD8+ , та прямі СD3-57+ НК і СD3+ 57+ НКТ з віком відмічені у цивільних осіб, які пройшли обстеження після початку війни.У військовослужбовців ЗСУ виявлено прямий кореляційний зв’язок між СD3+57+ НКТ та віком.Висновки. Імунологічний профіль як учасників ЛНА на ЧАЕС, так і військовослужбовців ЗСУ або цивільних осіб був подібним при внутрішньогруповому порівнянні з референтними показниками. Міжгрупове дослідження виявило зміни у субпопуляційному розподілі лейкоцитів периферичної крові, що можуть бути пов’язані як зі старінням, так і зміною умов життя під час воєнних дій. Визначені зміни клітинного імунітету можуть як спрямувати баланс у бік інфламейджингу, так і бути показником вже наявних імунопатологічних реакцій.

Research activities and scientific advance achieved in 2022 at the State Institution «National Research Center for Radiation Medicine of the National Academy of Medical Sciences of Ukraine» (NRCRM) concerning medical problems of the Chornobyl disaster, radiation medicine, radiobiology, radiation hygiene and epidemiology in collaboration with the WHO network of medical preparedness and assistance in radiation accidents are outlined in the annual report. The report presents the results of fundamental and applied research works of the study of radiation effects and health effects of the Chornobyl accident. The report also shows the results of scientificorganizational and health care work, staff training. The Scientific Council meeting of NAMS approved the NRCRM Annual Report.
Щорічний звіт відображує основні результати діяльності Державної установи «Національний науковий центр радіаційної медицини Національної академії медичних наук України» (ННЦРМ) з медичних проблем Чорнобильської катастрофи, радіаційної медицини, радіобіології, радіаційної гігієни та епідеміології, співпраці з ВООЗ в мережі медичної готовності та допомоги при радіаційних аваріях у 2022 р. У звіті представлені результати виконання науково-дослідних робіт фундаментального та прикладного характеру щодо вивчення радіаційних ефектів і медичних наслідків аварії на ЧАЕС. У звіті також відображено результати науково-організаційної, лікувально-профілактичної роботи, підготовки кадрів та впровадження. Звіт ННЦРМ затверджено Науковою радою НАМН України.

Activity concentrations of 90Sr in fish in lakes located within the Chornobyl Exclusion Zone (ChEZ) reach 100 kBq kg-1, which is several thousand times higher than the permissible level in Ukraine (35 Bq kg-1). This study was conducted in the natural conditions of the ChEZ to determine the effectiveness of keeping radioactively contaminated fish in \"clean\" water to reduce the 90Sr content of their muscle tissue, as previously shown in short-term laboratory experiments. It was found that transferring tench (Tinca tinca (Linnaeus, 1758)) from Lake Glubokoye one of the most contaminated lakes in the ChEZ, to a cage in the \"clean\" Lake Starukha for 45 days did not lead to a significant decrease in 90Sr content in both bone and muscle tissues. Establishing permissible levels of 90Sr concentration only in fish fillet, and not in the whole fish body (with bone tissue), is appropriate for human radiation protection, since the retention factors of 90Sr treatment for boiled bone tissue of crucian carp from the Chornobyl exclusion zone are less than 0.01, and up to 97% of strontium is contained in bone tissue.

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 is an environmental factor that elevates the risk of developing thyroid cancer. Actual and possible scenarios of exposures to external and internal radiation are multiple and diverse. This article reviews radiation doses to the thyroid and corresponding cancer risks due to planned, existing, and emergency exposure situations, and medical, public, and occupational categories of exposures. Any exposure scenario may deliver a range of doses to the thyroid, and the risk for cancer is addressed along with modifying factors. The consequences of the Chornobyl and Fukushima nuclear power plant accidents are described, summarizing the information on thyroid cancer epidemiology, treatment, and prognosis, clinicopathological characteristics, and genetic alterations. The Chornobyl thyroid cancers have evolved in time: becoming less aggressive and driver shifting from fusions to point mutations. A comparison of thyroid cancers from the 2 areas reveals numerous differences that cumulatively suggest the low probability of the radiogenic nature of thyroid cancers in Fukushima. In view of continuing usage of different sources of radiation in various settings, the possible ways of reducing thyroid cancer risk from exposures are considered. For external exposures, reasonable measures are generally in line with the As Low As Reasonably Achievable principle, while for internal irradiation from radioactive iodine, thyroid blocking with stable iodine may be recommended in addition to other measures in case of anticipated exposures from a nuclear reactor accident. Finally, the perspectives of studies of radiation effects on the thyroid are discussed from the epidemiological, basic science, and clinical points of view.

A worldwide increase in the incidence of thyroid cancer during the last decades is largely due to papillary thyroid microcarcinomas (MPTCs), which are mostly low-risk tumors. In view of recent clinical recommendations to reduce the extent of surgery for low-risk thyroid cancer, and persisting uncertainty about the impact of radiation history, we set out to address whether clinicopathological characteristics and prognosis of post-Chornobyl MPTCs were changing with regard to: i) the latency period, ii) probability of causation (POC) of a tumor due to radiation, and iii) tumor size.
Patients (n = 465) aged up to 50 years at diagnosis who lived in April, 1986 in six northern, most radiocontaminated regions of Ukraine were studied.
Latency period was statistically significantly associated with the reduction of POC level, tumor size and the frequency of fully encapsulated MPTCs. In contrast, the frequency of oncocytic changes and the BRAFV600E mutation increased. Invasive properties and clinical follow-up results did not depend on latency except for a lower frequency of complete remission after postsurgical radioiodine therapy. The POC level was associated with more frequent extrathyroidal extension, and lymphatic/vascular invasion, less frequent oncocytic changes and BRAFV600E , and did not associate with any clinical indicator. Tumor size was negatively associated with the latency period and BRAFV600E , and had a statistically significant effect on invasive properties of MPTCs: both the integrative invasiveness score and its components such as lymphatic/vascular invasion, extrathyroidal extension and lymph node metastases increased. The frequency of total thyroidectomy, neck lymph node dissection and radioiodine therapy also increased with the larger tumor size. The duration of the latency period, POC level or tumor size did not associate with the chance of disease recurrence.
In summary, we did not observe overall worsening of the clinicopathological features or treatment results of radiogenic MPTCs that could be associated with the latency period or POC level, suggesting that radiation history did not strongly affect those in the analyzed MPTC patients. However, the increase in the invasive properties with tumor size indicates the need for individual risk stratification for each MPTC patient, regardless of radiation history, for treatment decision-making.

OBJECTIVE: to establish cellular immunity in clean-up workers of the Chornobyl accident compared to patients with malignant neoplasms of the oral cavity, oral and laryngeal parts of the pharynx according to the subpopulation organization of peripheral blood leukocytes.
METHODS: We examined 112 males, age (56,92 ± 6,17) years (M ± SD), including 26 male clean-up workers exposed at the radiation dose 10-500 mSv; 20 male clean-up workers exposed at the dose range 504-990mSv; 33 patients with malignant neoplasms of the oral cavity, oral and laryngeal parts of the pharynx and 33 non-exposed subjects of the control group. Immune cell subsets analysis was performed by the expression of differential and activation antigens of peripheral blood leukocytes using flow cytometry.
RESULTS: In assessing each group\'s cellular immunity, there was a decrease in the number of CD19+ B-lymphocytes, CD3+ HLA-DR+ T- and CD3- HLA-DR+ B-lymphocytes, CD3- 16+ 56+ natural killer cells, combined with an increase in the number of CD8+ T-lymphocytes. An increase in the relative number of CD4+ CD8+ T-lymphocytes was determined in clean-up workers (D < 500 mSv) and cancer patients. An increase in the number of CD8+ T-lymphocytes and a decrease in the number of CD4+ T-lymphocytes were observed in clean-up workers (D > 500 mSv), as well as in cancer patients. In addition, a decrease of monocytes, CD3+ 16+ 56+ , and CD3+ TCRαβ+ T-lymphocytes was determined in patients with oncological pathology.
CONCLUSIONS: The obtained results show the unidirectionality of changes in cellular immunity in the participants of the liquidation of the consequences of the accident at the Chornobyl nuclear power plant and patients with the investigated oncological pathology, which indicates the formation of persistent violations of antitumor protection in the participants of the liquidation of the consequences of the accident as the basis of oncogenesis. Determining changes in the number of lymphocytes, monocytes, granulocytes, CD4+ T-lymphocytes, CD4+ CD8+ immature T-lymphocytes, the immunoregulatory ratio CD4+ / CD8+, CD3+TCRαβ+ T-lymphocytes and CD3+ 16+ 56+ CTL can have an additional effect on the effectiveness antitumor protection and the probability of oncogenesis risk in immunocompromised individuals.
Meta: vyznachyty zminy klitynnoï lanky imunnoï systemy v uchasnykiv likvidatsiï naslidkiv avariï na ChAES u porivnianni z khvorymy na zloiakisni novoutvorennia porozhnyny rota, rotovoï ta gortannoï chastyn glotky za subpopuliatsiĭnoiu organizatsiieiu leĭkotsytiv peryferychnoï krovi.Materialy i metody. Obstezheno 112 cholovikiv u vitsi (56,92 ± 6,17) rokiv, sered nykh: 26 uchasnykiv likvidatsiï naslidkiv avariï na ChAES, oprominenykh u diapazoni doz 10–500 mZv ta 20 uchasnykiv likvidatsiï naslidkiv avariï na ChAES, oprominenykh u diapazoni doz 504–990 mZv; 33 khvorykh na zloiakisni novoutvorennia porozhnyny rota, rotovoï ta gortannoï chastyn glotky III, IVA i IVV stadiĭ zakhvoriuvannia (grupa pozytyvnogo kontroliu); ta 33 osoby kontrol\'noï grupy. Analiz subpopuliatsiĭnogo rozpodilu provodyly za ekspresiieiu dyferentsiĭnykh ta aktyvatsiĭnykh antygeniv leĭkotsytiv peryferychnoï krovi z vykorystanniam protochnoï tsytometriï.Rezul\'taty. V usikh grupakh obstezhennia vyiavleno znyzhennia vidnosnoï kil\'kosti CD19+ V-limfotsytiv, CD3+ HLA-DR+ T- i CD3- HLA-DR+ V-limfotsytiv, SD3- 16+ 56+ natural\'nykh kileriv na foni pidvyshchennia chysla CD8+ T-limfotsytiv.V uchasnykiv likvidatsiï naslidkiv avariï na ChAES (D < 500 mZv) ta onkologichno khvorykh patsiientiv vyznacheno zrostannia vidnosnoï kil\'kosti CD4+CD8+ T-limfotsytiv. V uchasnykiv likvidatsiï naslidkiv avariï na ChAES (D > 500 mZv),iak i v onkologichno khvorykh patsiientiv sposterigalosia pidvyshchennia vidnosnoï kil\'kosti CD8+ T-limfotsytiv, znyzhennia kil\'kosti CD4+ T-limfotsytiv. Dodatkovo v osib, khvorykh na onkologichnu patologiiu vyznacheno znyzhennia pokaznykiv monotsytiv, SD3+ 16+ 56+ ta SD3+ TCRαβ+ T-limfotsytiv.Vysnovky. Otrymani rezul\'taty pokazuiut\' odnospriamovanist\' zmin klitynnogo imunitetu v uchasnykiv likvidatsiï naslidkiv avariï na ChAES i khvorykh na doslidzhenu onkologichnu patologiiu, shcho svidchyt\' pro formuvannia v uchasnykiv likvidatsiï naslidkiv avariï stiĭkykh porushen\' protypukhlynnogo zakhystu iak pidґruntia onkogenezu. Vyznacheni zminy pokaznykiv limfotsytiv, monotsytiv, granulotsytiv, CD4+ T-limfotsytiv, CD4+ CD8+ nezrilykh T-limfotsytiv, pokaznyka imunoreguliatornogo koefitsiienta CD4+ / CD8+, SD3+ TCRαβ+ T-limfotsytiv ta SD3+ 16+ 56+ tsytotoksychnykh T-limfotsytiv mozhut\' chynyty dodatkovyĭ vplyv na efektyvnist\' protypukhlynnogo zakhystu ta ĭmovirnist\' ryzyku onkogenezu v imunoskomprometovanykh osib.