External Gamma Rays Research Articles

Роль клеточного иммунитета в развитии злокачественных новообразований у лиц, подвергшихся хроническому облучению

Some long-term effects of radiation could be related to changes in the immune system resulting from radiation exposure. Immunity disorders caused by radiation can influence carcinogenesis. Cellular immunity factors were investigated in peripheral blood of workers chronically exposed to occupational combined radiation (external gamma-rays and internal alpha-particles), with malignant neoplasms diagnosed after blood samples were taken or without them, and in the control group. The aim of this study was examine effects of radiation on the cellular immunity status in individuals chronically exposed to ionizing radiation who had malignant neoplasms developed after blood sampling. The relative and absolute number of lymphocyte subpopulations (total T-cells, T-helpers, T-cytotoxic, total B-cells, NK-cells, NKT-cells and activated T-cells) was detected by flow cytofluorometry. The absolute number of T-cells was significantly reduced in workers chronically exposed to occupational combined irradiation, with or without malignancies, compared to the control, which may contribute to tumor progression at an early stage of its onset. At the same time, workers without malignancies had a significant increase in the relative number of T-cytotoxic lymphocytes, which may be a factor preventing tumor development. A significant increase in the relative number of natural killer cells (NK cells) was detected in individuals with malignant neoplasms chronically exposed to occupational combined irradiation, compared with the control, which may indicate enhanced antitumor defense that developed in response to exposure to tumor antigens. In addition, a significant decrease in the absolute and relative number of T- and B-lymphocytes was found in the group of workers with malignant neoplasm, compared with the control. A significant increase in the relative number of T-helpers was found in both groups of workers. Since the role of T-helpers in the antitumor response is ambiguous, additional research on types of T-helpers is planned to clarify the results of the present study

Role of cellular immunity in malignant tumors development in individuals chronically ex-posed to ionising radiation

Some long-term effects of radiation could be related to changes in the immune system resulting from radiation exposure. Immunity disorders caused by radiation can influence carcinogenesis. Cellular immunity factors were investigated in peripheral blood of workers chronically exposed to occupational combined radiation (external gamma-rays and internal alpha-particles), with malignant neoplasms diagnosed after blood samples were taken or without them, and in the control group. The aim of this study was examine effects of radiation on the cellular immunity status in individuals chronically exposed to ionizing radiation who had malignant neoplasms developed after blood sampling. The relative and absolute number of lymphocyte subpopulations (total T-cells, T-helpers, T-cytotoxic, total B-cells, NK-cells, NKT-cells and activated T-cells) was detected by flow cytofluorometry. The absolute number of T-cells was significantly reduced in workers chronically exposed to occupational combined irradiation, with or without malignancies, compared to the control, which may contribute to tumor progression at an early stage of its onset. At the same time, workers without malignancies had a significant increase in the relative number of T-cytotoxic lymphocytes, which may be a factor preventing tumor development. A significant increase in the relative number of natural killer cells (NK cells) was detected in individuals with malignant neoplasms chronically exposed to occupational combined irradiation, compared with the control, which may indicate enhanced antitumor defense that developed in response to exposure to tumor antigens. In addition, a significant decrease in the absolute and relative number of T- and B-lymphocytes was found in the group of workers with malignant neoplasm, compared with the control. A significant increase in the relative number of T-helpers was found in both groups of workers. Since the role of T-helpers in the antitumor response is ambiguous, additional research on types of T-helpers is planned to clarify the results of the present study.

The risk of colorectal cancer incidence in a cohort of individuals occupationally exposed to ionizing radiation

The increased risk of colorectal cancer following ionizing radiation exposure was demonstrated in a number of epidemiological studies. Earlier, no impact of occupational radiation exposure on colorectal cancer incidence or mortality was observed in a cohort of workers of the nuclear industrial facility, Mayak Production Association (PA). Extension of the follow-up of the cohort and improvement of dose estimates for personnel made it possible to update the earlier findings. The study objective is to assess the risk of colorectal cancer incidence associated with chronic occupational radiation exposure taking into account non-radiation factor effects. The study cohort included 22,377 workers employed at the reactor, plutonium-producing and radiochemical plants of Mayak PA (hiring period 1948–1982; follow-up period ended on December 31, 2018). Using the Poisson regression (EPICURE software), the relative risks (RRs with 95 % confidence intervals, (95 % CI)) of colorectal cancer incidence were estimated depending on the most significant non-radiation factors (sex, age, smoking, alcohol consumption, excessive body mass and obesity, intestinal polyps, chronic colitis). These values were also calculated for certain ranges of occupational exposure doses relying on data provided by ‘The Mayak Worker Dosimetry System – 2013’. The linear model was used to analyze the dose-response relationship. In the study cohort, the RR of colorectal cancer incidence was lower in females than in males: 0.72 (95 % CI: 0.55; 0.96) for colon and 0.48 (95 % CI: 0.34; 0.67) for rectum. The increased RR of the rectum cancer incidence was observed for cases with intestinal polyps: 3.42 (95 % CI: 1.68; 6.19). The colon cancer incidence risk increased with increasing age of workers, but other non-radiation factors were not shown to affect the results. This study supported the earlier results: no association was observed between the risk of colorectal cancer incidence and doses of occupational external gamma-ray or internal alpha-particle exposures.

Риск заболеваемости раком кишечника в когорте работников, подвергшихся хроническому профессиональному облучению

The increased risk of colorectal cancer following ionizing radiation exposure was demonstrated in a number of epidemiological studies. Earlier, no impact of occupational radiation exposure on colorectal cancer incidence or mortality was observed in a cohort of workers of the nuclear industrial facility, Mayak Production Association (PA). Extension of the follow-up of the cohort and improvement of dose estimates for personnel made it possible to update the earlier findings. The study objective is to assess the risk of colorectal cancer incidence associated with chronic occupational radiation exposure taking into account non-radiation factor effects. The study cohort included 22,377 workers employed at the reactor, plutonium-producing and radiochemical plants of Mayak PA (hiring period 1948–1982; follow-up period ended on December 31, 2018). Using the Poisson regression (EPICURE software), the relative risks (RRs with 95 % confidence intervals, (95 % CI)) of colorectal cancer incidence were estimated depending on the most significant non-radiation factors (sex, age, smoking, alcohol consumption, excessive body mass and obesity, intestinal polyps, chronic colitis). These values were also calculated for certain ranges of occupational exposure doses relying on data provided by ‘The Mayak Worker Dosimetry System – 2013’. The linear model was used to analyze the dose-response relationship. In the study cohort, the RR of colorectal cancer incidence was lower in females than in males: 0.72 (95 % CI: 0.55; 0.96) for colon and 0.48 (95 % CI: 0.34; 0.67) for rectum. The increased RR of the rectum cancer incidence was observed for cases with intestinal polyps: 3.42 (95 % CI: 1.68; 6.19). The colon cancer incidence risk increased with increasing age of workers, but other non-radiation factors were not shown to affect the results. This study supported the earlier results: no association was observed between the risk of colorectal cancer incidence and doses of occupational external gamma-ray or internal alpha-particle exposures.

Highly sensitive gamma ray dosimeter based on dual-core photonic crystal fiber

This paper introduces the application of a photonic crystal fiber (PCF) sensor to be used as a gamma ray dosimeter. This paper proposes an efficient analysis of a highly sensitive surface Plasmon resonance for gamma ray dose detection in nuclear research reactors. The proposed structure makes use of a Poly-Vinyl Alcohol (PVA) polymer, which has high sensitivity to an external electric field and gamma rays making it suitable for nuclear reactor applications. At resonance frequency, the peak of spectral loss for dosimeter sensors refers to gamma irradiation dose values. Therefore, study the different geometrical parameters for the proposed PCF sensor is of significant importance to achieve high sensitivity with low spectral losses. The full-vectorial finite-element method has been used for analysis with the plane wave expansion method. The sensitivity of the suggested sensor achieves up to 0.006 µm per gamma-ray dose unit (μm/Gy) with low losses.

NaI(Tl) crystal scintillator encapsulated in two organic-scintillator layers with pulse shape data analysis

Thallium-doped sodium iodide (NaI(Tl)) crystals are widely used in radiation detection applications, from gamma-ray spectroscopy to particle dark matter searches. However, if the crystal is exposed to relative humidity of even a few percent, its light emission degrades, making the crystal impractical as a detector. Surrounding the crystal with organic scintillators not only protects the surface of the crystal from humid air but also offers a new capability to tag backgrounds such as external gamma rays and surface contaminations. We developed a detector that is constructed by fully encasing a NaI(Tl) crystal in a plastic scintillator and then immersing the plastic-crystal assembly in liquid scintillator. Using data collected from this triple phoswich detector, a pulse shape analysis is able to identify the various radiation signals from the three scintillators. Additionally, we find that the crystal's emission quality is maintained for a month.

Extended analysis of solid cancer incidence among the Nuclear Industry Workers in the UK: 1955-2011.

Radiation worker studies provide direct estimates of cancer risk after protracted low-dose exposures to external X-ray and gamma-ray irradiations. The National Registry for Radiation Workers (NRRW) started in 1976 and has become the largest epidemiological program of research on nuclear workers in the UK. Here, we report on the relationship between solid cancer incidence and external radiation at the low-dose levels in 172,452 NRRW cohort members of whom (90%) were men. This study is based on 5.25 million person-years of follow-up from 1955 through the end of 2011. In the range of accumulated low doses two-thirds of workers have doses of less than 10 mSv. This study is an updated analysis of solid cancer incidence data with an additional 10 years of follow-up over the previous analysis of the NRRW cohort (NRRW-3). A total of 18,310 cases of solid cancers based on a 10-year lag were registered and of these 43% of the solid cancer cases occurred during the latest 10 years. Poisson regression was used to investigate the relationship between solid cancers risk and protracted chronic low-dose radiation exposure. This study demonstrated for solid cancers a rapid decrease of risk at high external doses that appeared to be driven by the workers who were monitored for potential exposure to internal emitters and who had also received relatively high external doses. Among cohort members only exposed to external radiation, a strong association was found between external dose and solid cancers (ERR/Sv = 0.52, 95% CI: 0.11; 0.96, based on 13,199 cases). A similar pattern is also seen for lung cancer. Excluding lung cancer from the grouping of all solid cancers resulted in evidence of a linear association with external radiation dose (ERR/Sv = 0.24, 95% CI: 0.01; 0.49, based on 15,035 cases), so suggesting some degree of confounding by smoking. Statistically significantly increasing trends with dose were seen for cancers of the colorectal, bladder and pleura cancer. Some of these results should be treated with caution because of the limited corroborating evidence from other published studies. Information on internal doses as well as non-radiation factors such smoking would be helpful to make more definitive inferences.

Incidence risks for cerebrovascular diseases and types of stroke in a cohort of Mayak PA workers.

Incidence risks for cerebrovascular diseases (CeVD) and some types of stroke in a cohort of 22,377 Russian Mayak nuclear workers chronically exposed to ionising radiation and followed up until the end of 2018 are reported. Among total 9469 cases of CeVD, 2078 cases were strokes that included 262 hemorrhagic strokes (HS) and 1611 ischemic strokes (IS). Data evaluation was performed with categorical and dose-response analyses estimating the relative risk (RR) and excess relative risk (ERR) per unit cumulative liver absorbed dose of external gamma-ray or internal alpha-particle exposure based on a linear model utilizing the AMFIT module of the EPICURE software. CeVD incidence was found to be significantly associated with cumulative radiation dose: ERR/Gy was 0.37 (95% confidence interval (CI) 0.27, 0.47) in males and 0.47 (95% CI 0.31, 0.66) in females for external exposure, and 0.31 (95% CI 0.11, 0.59) in males and 0.32 (95% CI 0.11, 0.61) in females for internal exposure. When the model for the analysis of external radiation effect did not include an adjustment for alpha radiation dose (and vice versa), the radiogenic risk estimate increased notably both for males and for females. In contrast, exclusion from or inclusion in the model of additional adjustments for non-radiation factors did not notably change the risk estimates. ERR/Gy of external gamma dose for CeVD incidence significantly decreased with increasing attained age (males and females) and duration of employment (females). No significant associations of either stroke or its types with cumulative gamma-ray dose of external exposure or alpha-particle dose of internal exposure were found.

Risks of incidence of breast cancer in a cohort of females occupationally exposed to ionizing radiation

Breast cancer (BrCa) holds the first rank place in morbidity and mortality due to malignant neoplasms among Russian women. BrCa is a multifactorial disease and ionizing radiation is among factors that cause elevated risks of developing BrCa. Our research aim was to assess relative risk (RR) of incidence of BrCa among women who were occupationally exposed to chronic ionizing radiation taking into account radiation and non-radiation factors. RR of incidence of BrCa was analyzed in a cohort of women employed at a nuclear production enterprise, namely Mayak PA, in 1948–1982. 95 % of women started working at the enterprise at their reproductive age. All those women were chronically exposed to ionizing radiation at their workplaces. A mean cumulative breast absorbed dose of external gamma-ray exposure amounted to 0.45 (standard deviation was 0.68) Gy; an average cumulative muscle absorbed dose of internal alpha-particle exposure amounted to 0.003 (0.01) Gy. According to data taken from “Clinic” medical-dosimetric database, 165 BrCa cases were detected in 157 women of the analyzed cohort (8 women had BrCa in both breasts). Our analysis involved calculating RR of incidence of BrCa in relation to known non-radiation and radiation factors. Categorical data analysis was performed without age-related and calendar period-related stratification and with them. RR was analyzed based on Poisson regression with AMFIT module in EPICURE software package. Incidence of BrCa was revealed to be associated with attained age, age of menarche, age of menopause, number of abortions, age of concomitant diseases prior to cancer diagnosis, height, body mass index, age of hiring at the Mayak PA. There was no relationship between BrCa incidence and cumulative doses of occupational chronic external gamma-ray, internal alpha-particle and neutron exposure.

Оценка риска заболеваемости раком молочной железы в когорте работниц, подвергшихся профессиональному облучению

Breast cancer (BrCa) holds the first rank place in morbidity and mortality due to malignant neoplasms among Russian women. BrCa is a multifactorial disease and ionizing radiation is among factors that cause elevated risks of developing BrCa. Our research aim was to assess relative risk (RR) of incidence of BrCa among women who were occupationally exposed to chronic ionizing radiation taking into account radiation and non-radiation factors. RR of incidence of BrCa was analyzed in a cohort of women employed at a nuclear production enterprise, namely Mayak PA, in 1948–1982. 95 % of women started working at the enterprise at their reproductive age. All those women were chronically exposed to ionizing radiation at their workplaces. A mean cumulative breast absorbed dose of external gamma-ray exposure amounted to 0.45 (standard deviation was 0.68) Gy; an average cumulative muscle absorbed dose of internal alpha-particle exposure amounted to 0.003 (0.01) Gy. According to data taken from “Clinic” medical-dosimetric database, 165 BrCa cases were detected in 157 women of the analyzed cohort (8 women had BrCa in both breasts). Our analysis involved calculating RR of incidence of BrCa in relation to known non-radiation and radiation factors. Categorical data analysis was performed without age-related and calendar period-related stratification and with them. RR was analyzed based on Poisson regression with AMFIT module in EPICURE software package. Incidence of BrCa was revealed to be associated with attained age, age of menarche, age of menopause, number of abortions, age of concomitant diseases prior to cancer diagnosis, height, body mass index, age of hiring at the Mayak PA. There was no relationship between BrCa incidence and cumulative doses of occupational chronic external gamma-ray, internal alpha-particle and neutron exposure.

An analytical approach to organ equivalent dose estimation based on material composition photon attenuation coefficient

Monte Carlo photon transport calculation is widely used with anthropomorphic phantoms to estimate equivalent doses for different photon energies and exposure geometries. Although a high precision probabilistic method, it is computationally expensive. The uncertainties in the physical input parameters and deviations in the particle simulation from the actual exposure also limit the accuracy of the dose conversion coefficients. This study presents an analytical method of calculating the organ equivalent dose of virtual adults from external gamma radiation based on elemental tissue composition energy transfer, energy-absorption coefficient, and photon interaction. The two methods developed are based on ICRU-four and nine elements in tissues. The methods are subsequently used to estimate the equivalent dose for various organs in virtual male and female adults exposed to external monoenergetic gamma rays. The equivalent dose results from the simulated geometries show the accuracy and adaptability of the proposed method. The result is also in agreement with the International Commission on Radiological Protection (ICRP) publication 116. Moreover, the result shows that the proposed method can accurately calculate organ equivalent dose from external photon irradiation without considering the complex photon transport computations used in existing photon transport codes. In addition, compared with four other conventional approaches, the evaluation result shows that the proposed analytical approach enhances computation efficiency without compromising dose calculation accuracy.

Dose rates evaluation of some granitic rocks from the Paraná State

Granitic rocks, widely used as building materials, are known to contain natural radionuclides and can be an important source of radiation for the population. Thirty-four samples of granite rocks from geological occurrences in Paraná state were measured with an HPGe detector for evaluation of226Ra, 232Th and 40K activity concentrations. The effective annual external dose was evaluated from these radionuclides activities using a dosimetric room model with dimensions 4 m x 5 m x 2.8 m in which all wallsare internally coated with granites of thickness 2 cm and considering an annual exposure time of 7000 h. This value was suggested by the European Commission on Radiological Protection for superficial coating materials. The internal exposure was evaluated from radon air concentration of the model room, simulated from an exhalation rate of 222Rn, determined with CR-39 solid state nuclear track detectors using the sealed can technique, considering a ventilation rate of 0.5 h-1 and an annual exposure time of 7000 h. The results of this study showed that the increase in the annual effective dose ranged from 62 ± 3 μSv.a-1 to 138 ± 1 μSv.a-1 from external gamma rays and the increase in the annual effective dose ranged from 0.39 ± 0.04 μSv.a-1 to 70 ± 4 μSv.a-1 from radon inhalation. All results stayed below 1 mSv.a-1 recommended by the European Commission on Radiological Protection.

Biomarkers of Atherosclerotic Vascular Disease in Workers Chronically Exposed to Ionizing Radiation.

It is well established that cohorts of individuals exposed to ionizing radiation demonstrate increased risks of cardio- and cerebrovascular diseases. However, mechanisms of these radiation-induced diseases developing in individuals exposed to ionizing radiation remain unclear. To identify biomarkers of the atherosclerotic vessel damage in workers chronically exposed to ionizing radiation, this study considered 49 workers of the Russian nuclear production facility-the Mayak Production Association (mean age of 68.73 ± 6.92 years)-and 38 unexposed individuals (mean age of 68.84 ± 6.20 y) who had never been exposed to ionizing radiation (control). All workers were chronically exposed to combined radiation (external gamma rays and internal alpha particles). The mean cumulative liver absorbed dose from external gamma-ray exposure was 0.18 ± 0.12 Gy; the mean cumulative liver absorbed dose from internal alpha-particles was 0.14 ± 0.21 Gy. Levels of biomarkers in blood serum of the study participants were measured using the ELISA method. Elevated levels of apolipoprotein B, superoxide dismutase, monocyte chemoattractant protein 1, vascular cell adhesion protein 1, and a decreased level of endothelin-1 were observed in blood serum of Mayak PA workers chronically exposed to combined radiation compared to control individuals. A significant positive correlation was demonstrated between the vascular cell adhesion protein 1 level and cumulative liver absorbed doses from external gamma radiation and internal alpha radiation. Findings of the study suggest that molecular changes in blood of individuals occupationally exposed to ionizing radiation (combined internal exposure to alpha particles and external exposure to gamma rays) may indicate dyslipidemia, oxidative stress, inflammation, and endothelial dysfunction involved in atherosclerosis development.

Lung Cancer in the Mayak Workers Cohort: Risk Estimation and Uncertainty Analysis.

The workers at the Mayak nuclear facility near Ozyorsk, Russia are a primary source of information about exposure to radiation at low-dose rates, since they were subject to protracted exposures to external gamma rays and to internal exposures from plutonium inhalation. Here we re-examine lung cancer mortality rates and assess the effects of external gamma and internal plutonium exposures using recently developed Monte Carlo dosimetry systems. Using individual lagged mean annual lung doses computed from the dose realizations, we fit excess relative risk (ERR) models to the lung cancer mortality data for the Mayak Workers Cohort using risk-modeling software. We then used the corrected-information matrix (CIM) approach to widen the confidence intervals of ERR by taking into account the uncertainty in doses represented by multiple realizations from the Monte Carlo dosimetry systems. Findings of this work revealed that there were 930 lung cancer deaths during follow-up. Plutonium lung doses (but not gamma doses) were generally higher in the new dosimetry systems than those used in the previous analysis. This led to a reduction in the risk per unit dose compared to prior estimates. The estimated ERR/Gy for external gamma-ray exposure was 0.19 (95% CI: 0.07 to 0.31) for both sexes combined, while the ERR/Gy for internal exposures based on mean plutonium doses were 3.5 (95% CI: 2.3 to 4.6) and 8.9 (95% CI: 3.4 to 14) for males and females at attained age 60. Accounting for uncertainty in dose had little effect on the confidence intervals for the ERR associated with gamma-ray exposure, but had a marked impact on confidence intervals, particularly the upper bounds, for the effect of plutonium exposure [adjusted 95% CIs: 1.5 to 8.9 for males and 2.7 to 28 for females]. In conclusion, lung cancer rates increased significantly with both external gamma-ray and internal plutonium exposures. Accounting for the effects of dose uncertainty markedly increased the width of the confidence intervals for the plutonium dose response but had little impact on the external gamma dose effect estimate. Adjusting risk estimate confidence intervals using CIM provides a solution to the important problem of dose uncertainty. This work demonstrates, for the first time, that it is possible and practical to use our recently developed CIM method to make such adjustments in a large cohort study.

Регистр плутониевого пневмофиброза в когорте работников предприятия атомной промышленности ПО «Маяк»

The registry of plutonium-induced lung fibrosis cases (PuLF) diagnosed in members of a cohort of the first Russian nuclear industry facility Mayak Production Association was established in the clinical department of the Southern Urals Biophysics Institute of the Federal Medical-Biological Agency (SUBI). The registry includes 188 plutonium-induced lung fibrosis diagnoses: 117 (62.23%) in males and 71 (37.77%) in females. This paper describes the structure and detailed characteristics of the registry. The number of PuLF cases was shown to have no association with cumulative lung absorbed dose from external gamma rays as of the date of diagnosis. On the contrary, the PuLF rate was shown to be associated with cumulative lung absorbed dose from in-corporated alpha particles and to increase significantly with increasing dose from internal radia-tion exposure. This paper discusses potential applications of the registry to scientific investiga-tions in the future.

حساب تركيز النظائر المشعة الطبيعية والصناعية لنماذج تربة جنوب منطقة الدورة في محافظة بغداد، العراق

تم قياس وتحليل النشاط المحدد للعناصر المشعة الطبيعية والاصطناعية في تسع عينات للتربة في مواقع مختلفة من منطقة الدورة الجنوبية، محافظة بغداد، العراق باستخدام كاشف أشعة كاما NaI (Tl). تم العثور على متوسط تركيزات النشاط من 238U و232Th و40K و137C لتكون 38.22 بيكريل/ كغم و42.99 بيكريل/ كغم و16.64 بيكريل/ كغم و2.92 بيكريل/ كغم على التوالي. العديد من مؤشرات الخطر الإشعاعي بما في ذلك نشاط مكافئ الراديوم (Raeq) ، ومعدل الجرعة الممتصة (D) ، ومؤشرات الخطر الداخلية (Hin) والخارجية (Hex) ، الداخلية (AEDEin) والخارجية (AEDEex) المكافئ الفعال للجرعة السنوية ومؤشر أشعة كاما (Iγr) ) محسوبة. إن نتائج جميع مؤشرات الخطر الإشعاعي أقل من قيمها الدولية. تكشف هذه الدراسة أن معظم المواقع في منطقة الدراسة آمنة من أي مخاطر إشعاعية.

Chronic Occupational Exposure to Ionizing Radiation Induces Alterations in the Structure and Metabolism of the Heart: A Proteomic Analysis of Human Formalin-Fixed Paraffin-Embedded (FFPE) Cardiac Tissue.

Epidemiological studies on workers employed at the Mayak plutonium enrichment plant have demonstrated an association between external gamma ray exposure and an elevated risk of ischemic heart disease (IHD). In a previous study using fresh-frozen post mortem samples of the cardiac left ventricle of Mayak workers and non-irradiated controls, we observed radiation-induced alterations in the heart proteome, mainly downregulation of mitochondrial and structural proteins. As the control group available at that time was younger than the irradiated group, we could not exclude age as a confounding factor. To address this issue, we have now expanded our study to investigate additional samples using archival formalin-fixed paraffin-embedded (FFPE) tissue. Importantly, the control group studied here is older than the occupationally exposed (>500 mGy) group. Label-free quantitative proteomics analysis showed that proteins involved in the lipid metabolism, sirtuin signaling, mitochondrial function, cytoskeletal organization, and antioxidant defense were the most affected. A histopathological analysis elucidated large foci of fibrotic tissue, myocardial lipomatosis and lymphocytic infiltrations in the irradiated samples. These data highlight the suitability of FFPE material for proteomics analysis. The study confirms the previous results emphasizing the role of adverse metabolic changes in the radiation-associated IHD. Most importantly, it excludes age at the time of death as a confounding factor.

Establishment of natural radioactivity baseline, mapping, and radiological hazard assessment in soils of Al-Qassim, Al-Ghat, Al-Zulfi, and Al-Majmaah

Radionuclide species comprising the primordial radioactive decay chains lead by 232Th and 238U, along with their associated daughter and granddaughter decay series, constitute a major fraction of the naturally occurring radioactive material (NORM). Gamma-ray radiation emitted by the decay of these NORMs, along with the 40K in the soil, is mainly responsible for the human exposure to external gamma-rays. The radioactivity concentrations in soil samples collected from 138 sites have been determined as part of a survey to produce a radiological map of AL-Qassim, Al-Ghat, Al-Majmaah, and Al-Zulfi regions in the Kingdom of Saudi Arabia. The estimated mean values of 238U, 232Th, 40K, 226Ra, and gross α and β activities in the samples were 23.8 ± 11.61, 24.33 ± 17.63, 790 ± 398, 22.83 ± 11.70, 375 ± 205, and 734 ± 344 Bq kg−1, respectively. The radiological risk indices related to the natural radioactivity in the soil samples, i.e., the absorbed dose rate in air, radium equivalent activity, and annual effective dose rate, were estimated to be 58.88 ± 29.21 nGy h−1, 117.1 ± 59.65 Bq kg−1, and 0.07 ± 0.04 mSv year−1, respectively. The determined internal hazard index of the samples ranged from 0.07 to 1.45, with an estimated mean value of 0.4 ± 0.2. The radon concentration in the soil gas ranged from 39 to 508 Bq m−3, with a mean value of 145.0 ± 52.9 Bq m−3.

Risk of stomach cancer incidence in a cohort of Mayak PA workers occupationally exposed to ionizing radiation.

Stomach cancer is a widespread health condition associated with environmental and genetic factors. Contribution of ionizing radiation to stomach cancer etiology is not sufficiently studied. This study was aimed to assess an association of the stomach cancer incidence risk with doses from occupational radiation exposure in a cohort of workers hired at main Mayak production association facilities in 1948–1982 taking into account non-radiation factors including digestive disorders. The study cohort comprised 22,377 individuals and by 31.12.2013 343 stomach cancer diagnoses had been reported among the cohort members. Occupational stomach absorbed doses were provided by the Mayak Worker Dosimetry System– 2008 (MWDS–2008) for external gamma ray exposure and by the Mayak Worker Dosimetry System– 2013 (MWDS–2013) for internal exposure to plutonium. Excess relative risks (ERR) per Gy for stomach cancer were estimated using the Poisson’s regression. Analyses were run using the AMFIT module of the EPICURE software. The stomach cancer incidence risk in the study cohort was found to be significantly associated with the stomach absorbed dose of gamma rays: ERR/Gy = 0.19 (95% CI: 0.01, 0.44) with a 0 year lag, and ERR/Gy = 0.20 (95% CI: 0.01, 0.45) with a 5 year lag. To estimate the baseline risk, sex, attained age, smoking status and alcohol consumption, chronic diseases (peptic ulcer, gastritis and duodenitis) were taken into account. No modifications of the radiogenic risk by non-radiation factors were found in the study worker cohort. No association of the stomach cancer incidence risk with internal exposure to incorporated plutonium was observed.

The ABRF Metabolomics Research Group 2016 Exploratory Study: Investigation of Data Analysis Methods for Untargeted Metabolomics.

Lack of standardized applications of bioinformatics and statistical approaches for pre- and postprocessing of global metabolomic profiling data sets collected using high-resolution mass spectrometry platforms remains an inadequately addressed issue in the field. Several publications now recognize that data analysis outcome variability is caused by different data treatment approaches. Yet, there is a lack of interlaboratory reproducibility studies that have looked at the contribution of data analysis techniques toward variability/overlap of results. The goal of our study was to identify the contribution of data pre- and postprocessing methods on metabolomics analysis results. We performed urinary metabolomics from samples obtained from mice exposed to 5 Gray of external beam gamma rays and those exposed to sham irradiation (control group). The data files were made available to study participants for comparative analysis using commonly used bioinformatics and/or biostatistics approaches in their laboratories. The participants were asked to report back the top 50 metabolites/features contributing significantly to the group differences. Herein we describe the outcome of this study which suggests that data preprocessing is critical in defining the outcome of untargeted metabolomic studies.