Long-term Effects Of Radiation Research Articles

REMOTE EFFECTS OF POST-CHORNOBYL IRRADIATION ON THE BIOCHEMICAL CHARACTERISTICS OF MALE SPERMATOZOA

The present research aim was analysis of long-term radiation effects on biochemical characteristics of sperm collected from donors originating from radioactive-polluted territories of Ukraine, namely Zhytomyr oblast, Ivano-Frankivsk oblast, Kyiv oblast and Poltava oblast. Apart from this, the role of radiation component in sperm damaging was assessed. It was found that in the most radiation polluted region - Zhytomyr the sperm samples were characterized by a large proportion of degenerative spermatozoa along with immobile sperms. Early signs of apoptosis development in spermatozoa were shown to progress gradually from Poltava to Zhytomyr. Thus, the apoptotic index for sperm samples was highest in Zhytomyr and lowest in Poltava. Also, raise in accumulated radiation dose was associated with elevation of ROS production in sperm samples. It was shown that the ROS production for Zhytomyr donors was threefold more than for Poltava’s donors and almost twofold more than for donors from Ivano-Frankivsk. Also we found differences in the mitochondrial potential (∆ψ) of spermatozoa too. The total ∆ψ tended to drop down depending on the mean value of radiation accumulated dose, for Kyiv and Zhytomyr the mean values being significantly less than for Poltava. Thus, our investigations have shown that subjects living on radiation polluted territories may generate a great deal of damaged spermatozoa with the hidden molecular and cellular lesions. The latter would predispose inhabitants of radiation polluted regions to male-infertility.

Long-Term Sex- and Genotype-Specific Effects of 56Fe Irradiation on Wild-Type and APPswe/PS1dE9 Transgenic Mice.

Space radiation presents a substantial threat to travel beyond Earth. Relatively low doses of high-energy particle radiation cause physiological and behavioral impairments in rodents and may pose risks to human spaceflight. There is evidence that 56Fe irradiation, a significant component of space radiation, may be more harmful to males than to females and worsen Alzheimer’s disease pathology in genetically vulnerable models. Yet, research on the long-term, sex- and genotype-specific effects of 56Fe irradiation is lacking. Here, we irradiated 4-month-old male and female, wild-type and Alzheimer’s-like APP/PS1 mice with 0, 0.10, or 0.50 Gy of 56Fe ions (1GeV/u). Mice underwent microPET scans before and 7.5 months after irradiation, a battery of behavioral tests at 11 months of age and were sacrificed for pathological and biochemical analyses at 12 months of age. 56Fe irradiation worsened amyloid-beta (Aβ) pathology, gliosis, neuroinflammation and spatial memory, but improved motor coordination, in male transgenic mice and worsened fear memory in wild-type males. Although sham-irradiated female APP/PS1 mice had more cerebral Aβ and gliosis than sham-irradiated male transgenics, female mice of both genotypes were relatively spared from radiation effects 8 months later. These results provide evidence for sex-specific, long-term CNS effects of space radiation.

Heating Effects in the Structure of Non-metamict Allanite-(La) from Palawan, Philippines

Allanite is one of the most common sources of rare-earth elements (REEs) and contains significant amounts of thorium (Th) and uranium (U). The presence of radioactive Th and U nuclides in the mineral exposes it to long-term radiation. Like other natural minerals containing Th and U, allanite can be used as a natural analog to understand the long-term radiation effects in high-level nuclear waste (HLW) matrices. Allanite group mineral is generally found in the amorphous phase due to structural damage induced by self-irradiation. In this work, crystalline allanite-(La) samples collected in San Vicente, Palawan, Philippines – having a low absorbed -dose of ~ 1014 α-decays/ mg – were heated at 450, 650, and 850 °C to study the response of non-metamict allanite to heating at elevated temperatures, particularly at the early stages of exposure to alpha-particle radiation. An increase in structural order was observed upon heating to 450 and 650 °C, which is exhibited by a decrease in the unit cell volume by 1.6% and a decrease of the full width at half maximum (FWHM) of selected Bragg planes. It was evident that certain Bragg planes respond differently to the annealing temperatures with preferential reorientation. After annealing at 850 °C, however, the loss of OH bonds was observed in the infrared (IR) spectra, and the broadening of Bragg peaks was seen in the x-ray diffraction (XRD) patterns, suggesting an onset of structural degradation. Surface cracks are also seen in the scanning electron microscope (SEM) images. The study shows that the non-metamict allanite-(La) mineral structure responds to heating similarly to that of metamict ones reported in the literature. This study will provide data on the properties of allanite as part of the ongoing studies on radiation damage in silicate matrices.

State of Immunological Reactivity of Rat’s Body after Exposure to Different Doses of γ-Radiation in a Long Period and their Offense of the 1st Generation

Abstract
 BACKGROUND: Recently, the problem of changes in immunological reactivity has become important with the growth of immunodeficiency states of a different nature. [4]. High radiosensitivity of the immune system, its stability in time and the irreversibility of some post-radiation changes can contribute to the development of long-term effects of radiation [2,3,6]. One of the tasks of modern medicine and biology is to study the effect of chronic or fractionated ionizing effects on the body's immune system both in the early and late periods of irradiation and their 1st generation descendants [1,2,3,11,12]. Therefore, it is necessary to study the long-term effects of sublethal and fractionated effects of g-radiation on the immunological reactivity of the organism, nonspecific phagocytic resistance and their 1st generation descendants.
 AIM: The aim of this study was to study the long-term effects of sublethal and fractionated effects of g-radiation on the immunological reactivity of the organism, nonspecific phagocytic resistance and their 1st generation descendants..
 METHODS: 7 series of experiments were performed on 105 white outbred sexually mature rats. 1-series intact (n=15), 2nd series - (n = 15) irradiated with a sublethal dose of 6 Gr. (1 month), 3rd series - irradiated with a sublethal dose (3 months, n = 20), 4 - descendants 1 - generations after sublethal dose, 5 series - irradiated with a fractionated dose (1 month), 6 series - irradiated with a fractionated dose (3 months), 7 - descendants of the 1st generation after fractionated -irradiation. Each series used 15 animals. Irradiation of animals 2 - 3 - 4 series was carried out on the Russian radiotherapy device "Agat-RM" -rays 60Co, the dose of sublethal irradiation is 6 Gr. Irradiation of animals of 5-6-7 series was carried out on the Russian radiotherapy device "Agat-RM" with 60Co-rays with topometric and dosimetric preparation of experimental animals, which facilitates the administration of a fractionated dose of 2 Gr. to animals three times within 3 weeks.
 RESULTS: In the long-term period after fractionated g-irradiation in the T-system of immunity, the following changes occur: against the background of an increase in the total number of lymphocytes, there is a decrease in the pool of CD3 +, CD4 + lymphocytes, immunoregulatory index, normalization of the lymphokine-producing ability of lymphocytes and a decrease in the pool of CD8 + lymphocytes. In the long-term period after fractionated g-irradiation in the humoral link of immunity, an increase in the absolute amount of CD19 + by 3.5 times was noted, which significantly exceeded the indicators of both control and intact animals. The percentage of this pool of cells exceeded the data of intact ones by 1.7 times. In the studied time period, the antibody-producing ability in the spleen increased from 22 ± 1.3 to 45 ± 2.6, without reaching, however, the level of intact animals. At the same time, there was a significant decrease in the suppression index to 13% (P<0.001) and the CIC concentration by 14 times (P<0.001) in the blood serum. The indicators of F/n and NST-test were high by 1.43 and 2.46 times, respectively. So, in the long-term period after exposure to a fractionated dose of g-radiation, the nonspecific phagocytic resistance of the organism is increased.
 CONCLUSIONS: The tension in the humoral link of immunity is manifested by a decrease in the quantitative and qualitative indicators and an increase in the functional and metabolic activity of neutrophils.

Association of Radiation to the Aorta and Blood Pressure Changes

Hypertension in patients receiving chemotherapy is a heavily documented and significant adverse event among cancer patients. In certain cases, radiotherapy may also be associated with sustained changes in blood pressure as an adverse outcome. Recent studies have shown that following head and neck radiotherapy there is sustained and significant blood pressure reduction without orthostatic changes. Additional evidence highlights hypertension due to radiation-induced renal artery stenosis. However, association of potential long-term effects of radiation to the aorta and concomitant changes in blood pressure have not been well documented. In this retrospective study, we evaluated changes in blood pressure among patients that likely received radiation dose to the aorta.We performed a retrospective cohort study of US national health records available within the Veterans Health Administration's (VA) Corporate Data Warehouse (CDW). All work was performed under local IRB approval (IRB #4234). The inclusion criteria for this study were Veterans with prostate, esophageal, pancreatic, and gastric cancers according to ICD-9 or ICD-10-CM codes. We divided the overall cohort (n = 70143) into the following groups: 1) esophageal, pancreas, and gastric cancer patients who received radiotherapy (irradiated aorta), 2) prostate cancer patients receiving brachytherapy (other radiation), and 3) esophageal, pancreas, prostate, and gastric cancer patients who did not receive radiotherapy (unirradiated). Pre and post-treatment vital signs (systolic blood pressure [SBP], diastolic blood pressure [DBP], and pulse pressure [PP]) were evaluated for all available time points. Course start date of radiation represented day 0 in the irradiated aorta and other radiation cohorts, while the average number of days from the first occurrence of initial diagnosis to course start date for respective cancers was considered day 0 in the unirradiated aorta cohort. Interrupted time series analyses were conducted using custom R scripts, with pairwise statistical comparisons by t-test.Within the cohort we observed no significant differences in pre vs. post-treatment changes in SBP, DBP, or PP for patients that did not receive radiation to the aorta across all disease sites. Similarly, there was no change in these metrics among patients with prostate cancer, whether or not they received brachytherapy. Interestingly, we observed no difference in pre- vs. post-treatment changes in SBP, DBP, or PP in patients with esophageal, pancreas, or gastric malignancies receiving radiation to the aorta - with the understanding that this is an unselected cohort regarding actual site of radiation, as we did not exclude patients receiving radiation to distant metastatic sites CONCLUSION: Our preliminary analysis demonstrates no evidence to suggest that presumptive radiation dose to the aorta results in significant changes to SBP, DBP, or PP in a mixed cohort of cancer patients.

Complex Long-term Effects of Radiation on Adult Mouse Behavior

We have shown previously that a single radiation event (0.063, 0.125 or 0.5 Gy, 0.063 Gy/min) in adult mice (age 10 weeks) can have delayed dose-dependent effects on locomotor behavior 18 months postirradiation. The highest dose (0.5 Gy) reduced, whereas the lowest dose (0.063 Gy) increased locomotor activity at older age independent of sex or genotype. In the current study we investigated whether higher doses administered at a higher dose rate (0.5, 1 or 2 Gy, 0.3 Gy/min) at the same age (10 weeks) cause stronger or earlier effects on a range of behaviors, including locomotion, anxiety, sensorimotor and cognitive behavior. There were clear dose-dependent effects on spontaneous locomotor and exploratory activity, anxiety-related behavior, body weight and affiliative social behavior independent of sex or genotype of wild-type and Ercc2S737P heterozygous mice on a mixed C57BL/6JG and C3HeB/FeJ background. In addition, smaller genotype- and dose-dependent radiation effects on working memory were evident in males, but not in females. The strongest dose-dependent radiation effects were present 4 months postirradiation, but only effects on affiliative social behaviors persisted until 12 months postirradiation. The observed radiation-induced behavioral changes were not related to alterations in the eye lens, as 4 months postirradiation anterior and posterior parts of the lens were still normal. Overall, we did not find any sensitizing effect of the mutation towards radiation effects in vivo.

Abstract 3059: Heavy ion radiation exposure perturbs intestinal stem cell homeostasis and induces accelerated tumorigenesis in apc mutant mouse intestine

Abstract In a previous study, we demonstrated long-term decreased intestinal epithelial cell migration after low-dose heavy ion iron radiation, and this was associated with increased senescence-associated secretory phenotype (SASP) signaling. However, we know very little about the long-term effects of low dose space radiation on intestinal stem cell (ISC) senescence and SASP that have implications for intestinal homeostasis. Male Lgr5+ (Lgr5-EGFP-IRES-creERT) mice or Lgr5+/APC1638N/+ were exposed to 0.5 Gy of sham, γ-rays, or 28Si (69 keV/μm) radiation and were euthanized 60 or 150 days after irradiation. ISCs were FACS sorted for oxidative stress analysis and assessed for senescence and SASP signaling in tissue sections by immunostaining. Greater cellROX or mitoSOX staining was observed after 28Si indicating higher oxidative stress compared to γ-rays or control Lgr5 positive cells. β-gal co-staining with Lgr5, lysozyme, IL1R, or ILβ showed highest staining in 28Si irradiated compared to controls ISCs samples. γ-H2AX staining showed greater foci numbers in 28Si relative to γ-rays or control group. Higher expression of secretory cytokines IL8 and IL15 was observed in 28Si irradiated ISCs relative to γ-rays or control group at both time points. Elevated expression of DKK2 and activation of NF-κB and p38 MAPK were observed in senescent stem cells of 28Si irradiated relative to γ-rays or control group at these time points. A higher GI tumor count was observed in 28Si compared to γ-irradiated or control Lgr5+/APC1638N/+ mice. In summary, our results demonstrate low dose heavy ion exposure induces ongoing DNA damage, persistent oxidative stress, senescence and acquisition of the SASP in ISCs. Higher levels of oxidative stress, senescence and SASP were observed at 150 compared to the 60-day timepoint. Overall, space radiation-induced oxidative stress, senescence, SASP, and activated p38MAPK/NF-κB pathway may very well have implications in GI carcinogenesis, accelerated aging, and pathological conditions, such as intestinal dysfunction, in astronauts during deep space flights. Since similar effects have been seen in our studies with other particle beams including carbon ions, this has potential relevance to particle radiotherapy as well. This work was supported by NASA NNX15AI21G Citation Format: Santosh Kumar, Shubhankar Suman, Kamal Datta, Albert J. Fornace. Heavy ion radiation exposure perturbs intestinal stem cell homeostasis and induces accelerated tumorigenesis in apc mutant mouse intestine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 3059.

Combined Coronary Artery Bypass Grafting and Transcatheter Aortic Valve Replacement in a Patient with Severe Post-Radiation Damage

Chest radiotherapy is a common treatment for mediastinal malignancy. The long-term effect of radiation can harm several of cardiovascular structures including pericardium, myocardium, valvular system, conduction system, and coronary arteries. Cardiovascular disease is the most common non-malignancy cause of death in radiation-treated patient, most often occurs many years after treatment. Valvular heart disease secondary to mediastinal radiation mainly affect the aortic and mitral valves. We present a unique case of 58 years old women with history of past mediastinal radiotherapy who presented with few episodes of true syncope, complete AV block, severe aortic stenosis and significant ostial left main and ostial right coronary artery disease.

Evaluating the long-term effect of space radiation on the reproductive normality of mammalian sperm preserved on the International Space Station.

Space radiation may cause DNA damage to cells and concern for the inheritance of mutations in offspring after deep space exploration. However, there is no way to study the long-term effects of space radiation using biological materials. Here, we developed a method to evaluate the biological effect of space radiation and examined the reproductive potential of mouse freeze-dried spermatozoa stored on the International Space Station (ISS) for the longest period in biological research. The space radiation did not affect sperm DNA or fertility after preservation on ISS, and many genetically normal offspring were obtained without reducing the success rate compared to the ground-preserved control. The results of ground x-ray experiments showed that sperm can be stored for more than 200 years in space. These results suggest that the effect of deep space radiation on mammalian reproduction can be evaluated using spermatozoa, even without being monitored by astronauts in Gateway.

Early postnatal irradiation\u2010induced age\u2010dependent changes in adult mouse brain: MRI based characterization

BackgroundBrain radiation exposure, in particular, radiotherapy, can induce cognitive impairment in patients, with significant effects persisting for the rest of their life. However, the main mechanisms leading to this adverse event remain largely unknown. A study of radiation-induced injury to multiple brain regions, focused on the hippocampus, may shed light on neuroanatomic bases of neurocognitive impairments in patients. Hence, we irradiated BALB/c mice (male and female) at postnatal day 3 (P3), day 10 (P10), and day 21 (P21) and investigated the long-term radiation effect on brain MRI changes and hippocampal neurogenesis.ResultsWe found characteristic brain volume reductions in the hippocampus, olfactory bulbs, the cerebellar hemisphere, cerebellar white matter (WM) and cerebellar vermis WM, cingulate, occipital and frontal cortices, cerebellar flocculonodular WM, parietal region, endopiriform claustrum, and entorhinal cortex after irradiation with 5 Gy at P3. Irradiation at P10 induced significant volume reduction in the cerebellum, parietal region, cingulate region, and olfactory bulbs, whereas the reduction of the volume in the entorhinal, parietal, insular, and frontal cortices was demonstrated after irradiation at P21. Immunohistochemical study with cell division marker Ki67 and immature marker doublecortin (DCX) indicated the reduced cell division and genesis of new neurons in the subgranular zone of the dentate gyrus in the hippocampus after irradiation at all three postnatal days, but the reduction of total granule cells in the stratum granulosun was found after irradiation at P3 and P10.ConclusionsThe early life radiation exposure during different developmental stages induces varied brain pathophysiological changes which may be related to the development of neurological and neuropsychological disorders later in life.

Long-Term Effects of Very Low Dose Particle Radiation on Gene Expression in the Heart: Degenerative Disease Risks

Compared to low doses of gamma irradiation (γ-IR), high-charge-and-energy (HZE) particle IR may have different biological response thresholds in cardiac tissue at lower doses, and these effects may be IR type and dose dependent. Three- to four-month-old female CB6F1/Hsd mice were exposed once to one of four different doses of the following types of radiation: γ-IR 137Cs (40-160 cGy, 0.662 MeV), 14Si-IR (4-32 cGy, 260 MeV/n), or 22Ti-IR (3-26 cGy, 1 GeV/n). At 16 months post-exposure, animals were sacrificed and hearts were harvested and archived as part of the NASA Space Radiation Tissue Sharing Forum. These heart tissue samples were used in our study for RNA isolation and microarray hybridization. Functional annotation of twofold up/down differentially expressed genes (DEGs) and bioinformatics analyses revealed the following: (i) there were no clear lower IR thresholds for HZE- or γ-IR; (ii) there were 12 common DEGs across all 3 IR types; (iii) these 12 overlapping genes predicted various degrees of cardiovascular, pulmonary, and metabolic diseases, cancer, and aging; and (iv) these 12 genes revealed an exclusive non-linear DEG pattern in 14Si- and 22Ti-IR-exposed hearts, whereas two-thirds of γ-IR-exposed hearts revealed a linear pattern of DEGs. Thus, our study may provide experimental evidence of excess relative risk (ERR) quantification of low/very low doses of full-body space-type IR-associated degenerative disease development.

Long-term behavior of normal weight concrete containing hybrid nanoparticles subjected to gamma radiation

Since a lot of medical facilities are made from normal weight concrete (NWC), it became an important task to improve the radiation shielding properties of such concrete in a confrontation to radiation with special emphasis on gamma radiation type. Therefore, an experimental program was conducted to investigate the effect of nanoparticles addition on gamma radiation shielding, physical properties, and mechanical properties of NWC. Nano silica (NS), nano hematite (NH), nano titania (NT), and their hybridization were added to NWC with four different percentages of 0.5, 0.75, 1.0, and 2.0% from the cement weight. A total of sixteen concrete mixes with nanoparticles in addition to a control mix were made. The long-term effects of gamma radiation on samples representing all concrete mixes were studied to find out the consequence of exposure to gamma rays over long periods (250 and 500 days) on their mechanical properties. The experimental results showed that the single addition of each of NS, NH, or NT particles and their combination up to 2.0% improved the physical properties, compressive strength, and attenuation coefficient of NWC. The results of the hybrid nano addition showed that the synergistic phenomenon occurred in some cases. Furthermore, the scanning electron microscopy technique (SEM) was used to prove the enhancement in the microstructure of NWC as a result of the addition of NS, NH, NT, and their combination.

A Process for the Synthesis and Use of Highly Aromatic Organosilanes as Additives for Poly(Vinyl Chloride) Films

Three organosilanes were synthesized in good yields from the condensation of 4,4′,4″-((phenylsilanetriyl)tris(oxy))tribenzaldehyde and 4-substituted anilines under acidic conditions. The structure of the organosilanes was confirmed using a variety of techniques. Organosilanes were mixed with poly(vinyl chloride) (PVC) and homogenous films were produced. The effect of long-term irradiation on the films containing organosilanes was tested using various methods. Monitoring the infrared spectra of PVC films before, during and after irradiation processes showed the formation of side products comprising polyene, carbonyl and hydroxyl groups. The intensities of absorption bands due to these functional groups were much lower in the presence of organosilanes as compared to the blank film. Also, the decrease in the weight and molecular weight of PVC films after irradiation was lower in the presence of organosilanes. Additionally, there was a minimal surface change of irradiated PVC in the presence of organosilanes. Clearly, organosilanes act as inhibitors, particularly the one containing the hydroxyl group, for the photodegradation of PVC. Different mechanisms were proposed to speculate the role played by organosilanes in stabilizing PVC against long-term ultraviolet light exposure.

Stigma perceptions, social media neighborhood storytelling, and future outlook in post-disaster Fukushima

ABSTRACT After more than nine years since the Great East Japan Earthquake struck Japan,the unresolved situation in FukushimaNuclear Power Plant and long-term effects of radiation continue to situate residents of Fukushima under the post-disaster context. This study examined the influence of Fukushima residents’ stigma perception and connectedness to offline and online neighborhood storytelling networks on future outlook. Based on an online survey of 936 Fukushima residents, the study found that residents who perceive higher stigma toward Fukushima from outsiders were more likely to have a negative future outlook than others. On the other hand, residents’ connectedness to the neighborhood storytelling network – consisting of interpersonal conversation, connectedness to community organizations andlocal media – was positively related to future outlook. With regard to online communication, people who engage in expressive storytelling about local affairs on social media, such as uploading stories or sharing information, were more likely to have a positive future outlook than others. Moreover, expressive storytelling about local affairs on social media was found to moderate the effect of stigma on future outlook: the negative effect of stigma on future outlook was mitigated for those who engage in expressive storytelling about local affairs. Implications of the results are discussed.

RBIO-06. IMPLEMENTATION OF HUMAN INDUCED PLURIPOTENT STEM CELL DERIVED CEREBRAL ORGANOIDS TO MODEL NORMAL TISSUE RADIORESPONSE

Abstract Treatment-related sequelae following cranial irradiation have life changing impacts for patients and their caregivers. Characterization of the basic response of human brain tissue to irradiation has been difficult due to a lack of preclinical models. The direct study of human brain tissue in vitro is becoming possible due to advances in stem cell biology, neuroscience, and tissue engineering with the development of organoids as novel model systems which enable experimentation with human tissue models. We sought to establish a cerebral organoid (CO) model to study the radioresponse of normal human brain tissue. COs were grown using human induced pluripotent stem cells and a modified Lancaster protocol. Compositional analysis during development of the COs showed expected populations of neurons and glia. We confirmed a population of microglia-like cells within the model positive for the makers Iba1 and CD68. After 2-months of maturation, COs were irradiated to 0, 10, and 20 Gy using a Shepard Mark-II Cs-137 irradiator and returned to culture. Subsets of COs were prepared for immunostaining at 30- and 70-days post-irradiation. To examine the effect of irradiation on the neural stem cell (NSC) population, sections were stained for SOX2 and Ki-67 expression denoting NSCs and proliferation respectively. Slides were imaged and scored using the CellProfiler software package. The percentage of proliferating NSCs 30-days post-irradiation was found to be significantly reduced for irradiated COs (5.7% (P=0.007) and 3.4% (P=0.001) for 10 and 20 Gy respectively) compared to control (12.7%). The reduction in the proliferating NSC population subsequently translated to a reduced population of NeuN-labeled mature neurons 70 days post-irradiation. The loss of proliferating NSCs and subsequent reduction in mature neurons demonstrates the long-term effects of radiation. Our initial results indicate COs will be a valuable model to study the effects of radiation therapy on normal and diseased human tissue.

Are Vegetation Dynamics Impacted from a Nuclear Disaster? The Case of Chernobyl Using Remotely Sensed NDVI and Land Cover Data

There is a growing interest for scientists and society to acquire deep knowledge on the impacts from environmental disasters. The present work deals with the investigation of vegetation dynamics in the Chernobyl area, a place widely known for the devastating nuclear disaster on the 26th of April 1986. To unveil any possible long-term radiation effects on vegetation phenology, the remotely sensed normalized difference vegetation index (NDVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS) was analyzed within the 30 km Exclusion Zone, where all human activities were ceased at that time and public access and inhabitation have been prohibited ever since. The analysis comprised applications of seasonal trend analysis using two techniques, i.e., pixel-wise NDVI time series and spatially averaged NDVI time series. Both techniques were applied in each one of the individual land cover types. To assess the existence of abnormal vegetation dynamics, the same analyses were conducted in two broader zones, i.e., from 30 to 60 km and from 60 to 90 km, away from Chernobyl area, where human activities were not substantially altered. Results of both analyses indicated that vegetation dynamics in the 30 km Exclusion Zone correspond to increasing plant productivity at a rate considerably higher than that of the other two examined zones. The outcome of the analyses presented herein attributes greening trends in the 30 km and the 30 to 60 km zones to a combination of climate, minimized human impact and a consequent prevalence of land cover types which seem to be well adapted to increased radioactivity. The vegetation greening trends observed in the third zone, i.e., the 90 km zone, are indicative of the combination of climate and increasing human activities. Results indicate the positive impact from the absence of human activities on vegetation dynamics as far as vegetation productivity and phenology are concerned in the 30 km Exclusion Zone, and to a lower extent in the 60 km zone. Furthermore, there is evidence that land cover changes evolve into the prevalence of woody vegetation in an area with increased levels of radioactivity.

Иммунный статус человека в отдалённом периоде хронического радиационного воздействия

Purpose: Assessment of major parameters of the system immunity in 376 Techa riverside residents affected by external γ- and internal (mainly due to 90Sr) irradiation 60–68 years after the onset of exposure.
 Material and methods: The study involved 376 residents of the settlements located in the basin of the Techa River which was contaminated due to releases of liquid radioactive waste of Mayak Production Association. Red bone marrow received the largest doses that reached 4457.1 mGy, mean dose value was 1080.8 ± 38.4 mGy. Doses to the thymus and peripheral organs of the immune system in the exposed individuals were much lower; mean dose value was 65.3 ± 4.9 mGy. The study of the systemic immunity included the analysis of the parameters that characterize functional status of adaptive and innate immunity, as well as of the cytokine system.
 Results: Pro-inflammatory changes of the cytokines spectrum (decrease of IL-4 in blood serum, increase of TNFα and IFNγ) were observed in exposed people with a background of involution changes.
 Conclusion: Persistent reduction in the number of neutrophils in blood against normal levels of granulocyte colony-stimulating and granulocyte-macrophage colony-stimulating factors in blood serum could be indicative of certain inefficiency of hematopoietic stem cell pool. The most distinct features of immunity in exposed persons concerned the cytokine spectrum which were inflammatory in nature and on the one hand could be involved in the mechanisms of development of long-term effects of radiation and on the other could have a protective effect on the protection of the body from cells carrying sublethal abnormalities.

Long-term effects of latitude, ambient temperature, and ultraviolet radiation on the incidence of multiple sclerosis in two cohorts of US women.

Differences in multiple sclerosis (MS) risk by latitude have been observed worldwide; however, the exposures driving these associations are unknown. Ultraviolet radiation (UV) has been explored as a risk factor, and ambient temperature has been correlated with disease progression. However, no study has examined the impact of all three exposures. We examined the association between these exposures and incidence of MS within two nationwide prospective cohorts of women, the Nurses' Health Study (NHS) and Nurses' Health Study II (NHSII). Both cohorts were followed with biennial questionnaires to ascertain new diagnoses and risk factors. Time-varying exposures to latitude, cumulative average July temperature (°C), and cumulative average July erythemal UV (mW/m2) were predicted at each participant's biennially updated residential addresses. Using Cox proportional hazards models adjusted for MS risk factors, we calculated hazard ratios (HR) and 95% confidence intervals (CIs) within each cohort and pooled via meta-analyses. In multivariable models, there were suggestions that decreasing latitude (meta-analysis multivariable-adjusted HR = 0.72; 95% CI 0.55, 0.94 for women living <35.73° compared with those ≥42.15°, P-for-trend = 0.007) and increasing cumulative average July temperature (meta-analysis multivariable-adjusted HR = 0.81; 95% CI 0.72, 0.91 for each interquartile range increase [3.91°]) were associated with decreasing risk of MS. There was no evidence of heterogeneity between cohorts. We did not observe consistent associations with cumulative average UV. Our results suggest that adult exposures to decreasing latitude and increasing temperature, but not UV, were associated with reduced MS risk in these two cohorts of women. Studies of MS incidence may want to consider temperature as a risk factor.

Transcriptional Changes in the Ovaries of Perch from Chernobyl.

Fish have been highly exposed to radiation in freshwater systems after the Chernobyl Nuclear Power Plant (NPP) accident in 1986 and in freshwater and marine systems after the more recent Fukushima NPP accident in 2011. In the years after the accident, the radioactivity levels rapidly declined due to radioactive decay and environmental processes, but chronic lower dose exposures persisted. To gain insights into the long-term effects of environmental low dose radiation on fish ovaries development, a high-throughput transcriptomic approach including a de novo assembly was applied to different gonad phenotypes of female perch: developed gonads from reference lakes, developed/irradiated from medium contaminated lake, and both developed/irradiated and undeveloped from more highly contaminated lakes. This is the most comprehensive analysis to date of the gene responses in wildlife reproductive system to radiation. Some gene responses that were modulated in irradiated gonads were found to be involved in biological processes including cell differentiation and proliferation (ggnb2, mod5, rergl), cytoskeleton organization (k1C18, mtpn), gonad development (nell2, tcp4), lipid metabolism (ldah, at11b, nltp), reproduction (cyb5, cyp17A, ovos), DNA damage repair (wdhd1, rad51, hus1), and epigenetic mechanisms (dmap1). Identification of these genes provides a better understanding of the underlying molecular mechanisms underpinning the development of the gonad phenotypes of wild perch and how fish may respond to chronic exposure to radiation in their natural environment, though causal attribution of gene responses remains unclear in the undeveloped gonads.

Effect of Si–Ni–P on the emergence of dislocations loops in Fe–9Cr matrix under neutron irradiation: TEM study and OKMC modelling

The expected degradation of mechanical properties of structural materials under irradiation (i.e. “in operation”) in nuclear components represents a significant challenge for the design to account the impact of long-term irradiation effects. Therefore, a development of scientific and engineering expertise to understand and possibly control the severe impact of harsh neutron irradiation on materials is one of the tasks in the current material’s research agenda. As it is well known from long-standing experience with fission systems, radiation embrittlement is caused by nano-scale features that obstruct plasticity mediated by dislocations. The present contribution highlights recent research and development efforts addressed towards the assessment of the interrelation between nano-structural features and hardening induced by neutron irradiation in fusion structural high-Cr ferritic/martensitic steels.In this work, the impact of doping by three chemical elements (nickel, silicon and phosphorus) on the microstructural evolution under neutron irradiation at 300 °C and 450 °C is studied experimentally as well as by computer simulations. The evolution of microstructure is assessed by transmission electron microscopy and object kinetic Monte Carlo simulations. The latter method utilizes a new approach enabling to follow both nano-scale irradiation defects and micro-segregation zones causing the formation of solute rich clusters, detectable by atom probe tomography. The results of the present work clearly point out that Ni–Si segregation alters the spatial and size distribution of dislocations loops already at as low dose as 0.1 dpa. The physical mechanisms behind the impact of minor alloying elements are discussed.