Effects Of Low-level Irradiation Research Articles

The truth will out: a reflection on the life and times of Alice Stewart

Purpose and conclusions Dr. Alice Stewart, 1906–2002, came from a medical background which included a strong commitment to social justice and equality. Her father became Professor of Medicine at Sheffield University and her mother was one of the first women to qualify as a doctor, and together they practiced in Hillsborough, near Sheffield. Having qualified as a doctor herself in 1932, Alice worked in London hospitals before moving to Oxford, where she became a pioneer in epidemiology. Early in her career, she showed that X-raying pregnant women was a cause of childhood leukemia. Her later work focused on the harmful effects of low-level radiation on nuclear industry workers, the role of background radiation and she went on to question the dose limits set for radiation protection. All her results were initially challenged, but subsequent studies have borne out her findings. Conclusions Dr Alice Stewart’s research was pioneering, fundamental and challenging, and is now widely accepted.

Оценка потенциальных радиологических рисков населения при реализации проекта «Прорыв» Госкорпорации «Росатом». Часть 1. Рекомендации МКРЗ

The concept “radiation detriment” has been debated intensively in the pages of the ICRP Publica-tion 103 (2007), new radiation epidemiological data obtained after 2007 have also been brought into discussion. For radiation detriment calculation radiation risk models based on data of the study of Japanese cohort of atomic bombings survivors were used. Models developed for esti-mating radiation risk factors take account of gender and age at exposure. Now ICRP has estimat-ed radiation detriment in specially designed standard population by averaging the estimates based on age at exposure. The concept “radiation detriment” was developed for quantification of the overall harm to health of humans and their offspring from stochastic effects of low-level radi-ation on different parts of the body, reduction in life expectancy and reduced quality of life. In ad-dition, radiation detriment is used to assess effective dose and its standardization for radiological protection. In the paper, the concept “radiation detriment” is assessed with regard to the possibility of extending the area of its application. The applicability of technique for calculation of radiation detriment is possible to be extended with account of Russian health and statistical data, lethality fraction estimates, years of life lost, gender and age. The extended “radiation detriment” will be renamed as “radiological detriment”, that will highlight the possibility of quantifying potential harm to a specific irradiated population. The magnitude of population-based radiological detri-ment may be used not only for matching sources of ionizing radiation by their impact on the standard population, but also for estimating the level of radiological protection of the specific population. The level of radiological detriment may be used for quantification of potential harm to the public health in the implementation of the Rosatom project “Proryv”.

Occupational exposure to chronic ionizing radiation increases risk of Parkinson's disease incidence in Russian Mayak workers.

Patients receiving radiotherapy demonstrate cognitive deficits, impairment of neurogenesis and neurovascular damage developing as late side effects of radiation exposure to the head. In light of the increasing use of diagnostic radiological procedures, epidemiological data raise concerns about possible harmful effects of low-level radiation on the human brain. A series of studies of chronically exposed Russian nuclear workers have provided information on risks of cancer and non-cancer diseases. This study aimed to assess the risk of Parkinson's-disease (PD) incidence in a cohort of workers occupationally exposed to chronic radiation. The cohort comprised workers of a Russian nuclear production facility who were first employed in 1948-1982 and followed up until the end of 2013 (22377 individuals; 25% female). Using the AMFIT module of EPICURE software, relative risk and excess relative risk per unit dose (ERR/Gy) were calculated based on maximum likelihood. A linear association was found between PD incidence and cumulative γ-dose after adjusting for sex and attained age [ERR/Gy = 1.02 (95% confidence interval, 0.59 to 1.63, p = 5.44 × 10-5)]. The ERR/Gy of external radiation for PD incidence was stable after adjusting for neutron dose (ERR/Gy = 1.03; 95% confidence interval: 0.59 to 1.67, p = 6.86 × 10-5). The risk increased with increasing lag period and decreased notably after adjusting for body mass index, smoking and alcohol consumption. Additional adjustments for hypertension, gout, gastric ulcer, head injuries with loss of awareness and diabetes mellitus did not affect the risk estimate. This study is the first to suggest that PD is associated with prolonged occupational external γ-ray exposure.

Biochemical Effect of Low-Level Radiation on Human Beings Examined by Directly Attached Radioactive Mineral

Previously, we have reported the clinical significance of low-level radiation and also demonstrated the necessity to determine the threshold of radioactive levels in human beings. In the present study, apart from the direct exposure of alpha-ray with oral intake of radon222 dissolved water or inhaling radon222 gas, the experimental direct exposure to beta- and gamma-rays by wearing a cotton sack containing Samarskite with direct contact to skin for one month was conducted. The average of beta- and gamma-ray levels on the sack surface was approximately 400 μSV/hour. The biochemical laboratory tests involving immunological markers were assessed at the initial and end points. In this study, the partial but continual direct exposure of human body to beta- and gamma-rays for one month showed no harmful effects. There are no significant changes in any of the bio markers. Although this study is limited regarding the number of subjects, the procedure is quite simple; thus, the gathering data using this procedure by adjusting the types and levels of radioactivity would be helpful in finding out the accurate radioactive threshold in human beings.

CLINICAL AND DOSIMETRIC INFORMATION TO SUPPORT LONG-TERM COHORT STUDY OF CHERNOBYL CLEAN-UP WORKERS IN RUSSIA.

The article describes the activities of the Russian National Radiation-Epidemiological Registry (NRER) as the unified federal information system for research and management of individual medical and dosimetry data of people exposed to radiation as a result of the Chernobyl accident and other radiological events. The NRER was created for long-term registration of lifetime changes in the health status of the registered people. We present medical and dosimetry data management process, which is carried out in compliance with approved protocols. The scope and content of the information to be collected from external resources are defined in the documents approved by the Russian Ministry of Health. As of 2017 reporting year, the NRER contains medical and dosimetry information on 205 044 clean-up workers of the Chernobyl accident (liquidators), collected during the follow-up period from 1986 to 2016. Using special software for management of data from long-term studies of the Russian cohort of Chernobyl liquidators NRER ensures high quality of radiation-epidemiological information. The results of research activities of the NRER make great contribution to understanding biological and health effects of low-level radiation, molecular mechanisms of the effects, development of actions to early diagnostic of radiation-related diseases to respond to the needs of the affected population while minimizing unnecessary anxiety, improvement of targeting treatments delivery to exposed people at high risk, development of measures to reduce health risks from medical radiological procedures. During the post-Chernobyl period, new methods for estimating radiation doses were developed, some of them can be used for express estimation of radiation dose in the event of radiological emergency.

Survey on low-dose medical radiation exposure in occupational workers: the effect on hematological change

This study examined the changes in the hematological index caused by low-dose medical radiation exposure in workers in a medical radiation-exposed environment. The cumulative dose was obtained using thermoluminescent dosimeters over a 9-year period, and the changes in hematological index count (red blood cells (RBCs), hemoglobin, platelets, white blood cells (WBCs), monocytes, lymphocytes, neutrophils, basophils, and eosinophils) were examined in both the occupational workers and controls. In total, 370 occupational workers and 335 controls were compared. The analysis led to the following observations: (1) The average cumulative dose in males and females was 9.65±15.2 and 4.82±5.55 mSv, respectively. (2) In both males and females, there was a very low correlation between the occupation period and the cumulative dose (r<±0.25). (3) When the occupation period was longer, the WBC counts both decreased and increased in the male workers and the RBC counts were lower in the workers than in the control group (p<0.05). In females, the WBC counts both decreased and increased in the workers and the eosinophil counts were lower in the workers than in the control group (p<0.01). (4) When the cumulative dose was large, the lymphocyte counts decreased in male workers and the platelet count was lower in the workers than in the control group (p<0.05). In females, the lymphocyte count and RBC count were lower in the workers than in the control group (p<0.05). Abnormal distributions of some blood indices were observed in the occupational radiation workers compared with the controls. Attempts were made to limit radiation exposure to personnel, but the employees did not always follow the preset rules. Actually, the adverse effects of low-level radiation were attributed to probability. Overall, workers should obey the radiation protection regulations provided by the government and a national system of radiation protection is needed.

Ionizing radiation exposure and the development of intervertebral disc degeneration—no case to answer

In the following perspective article, Mellor and Breen provide a counterpoint to a previous perspective on the potential link between ionizing radiation exposure and intervertebral disc degeneration in humans [1]. The previous perspective asked, is this link a myth or reality? It suggested the potential for such a link. Mellor and Breen offer a drastically alternate view, in essence, that the question itself is flawed. To support their perspective, they explain the different units of radiation measurement and their conversion to risk in humans and how this impacts the previous perspective. They explain the variable sensitivity of different body tissues to radiation and highlight that neither human research nor any of the multiple international regulatory agencies have ever suggested that the intervertebral disc is sensitive to radiation. Finally, they claim that it is impossible to predict with any certainty the effects of low-level radiation on the intervertebral discs.

The change in the structural and functional organization of the guerin's carcinoma cytochrome part of respiratory chain in tumor carriers in the conditions of preliminary low-level irradiation

The effect of low-level irradiation of tumor-bearing rats on the structural and functional organization of the cytochrome part of respiratory chain of mitochondria isolated from Guerin's carcinoma has been investigated. The maximal reduction in the mitochondrial cytochromes a, b and c content was observed at the terminal stage of Guerin's carcinoma. A low-level irradiation during initial stages of oncogenesis produced opposite changes in the mitochondrial cytochrome content. The possible mechanism of mitochondrial haem-containing cytochromes content reduction may be attributed to impairment in their formation caused by inhibition of the key enzyme of haem synthesis, 5-aminolevulinate synthase. The determined changes of the mitochondrial cytochromes quantitative content were accompanied by decreased activity of cytochrome oxidase. The preliminary low-level irradiation of the tumor-bearing animals produced further reduction in the cytochrome oxidase activity observed in all experimental periods.

Cancer mortality in six lowest versus six highest elevation jurisdictions in the u.s.

Low levels of background radiation exist around us continuously. These levels increase with increasing land elevation, allowing a comparison of low elevations to high elevations in regard to an outcome such as cancer death rates. The present study compares archived cancer mortality rates in six low versus six high elevation jurisdictions. The study also compares mortality rates for all causes, heart disease, and diabetes in low versus high elevation jurisdictions in an effort to see if other mortality outcomes are different in low versus high elevations. Statistically significant decreases in mortality, with very large effect sizes, were observed in high land elevation for three of the four outcomes, including cancer. One possible explanation for the decreased mortality in high elevation jurisdictions is radiation hormesis. Another possible explanation, at least in the case of heart disease mortality, is the physiologic responses that accompany higher elevations regarding decreased oxygen levels. Since this is an ecological study, no causal inferences can be made, particularly when viewpoints on possible effects of low level radiation are diametrically opposed. Further research is indicated.

Effect of Radiation on Human Intestinal Microvascular Endothelial Cells (HIMEC): Role of Akt/mTOR and NFκB

Radiation therapy is an essential modality in the treatment of colorectal cancers. Radiation exerts an anti‐angiogenic effect on tumors, inhibiting endothelial proliferation and survival in the tumor microvasculature. However, damage from low levels of irradiation can induce a paradoxical effect, stimulating survival in endothelial cells. We used HIMEC to define effects of low level radiation on these gut specific endothelial cells. 2 Gy of irradiation activates NFκB and the PI3K/Akt pathway, which is involved in cell cycle re‐entry and cell survival in HIMEC. A downstream target of PI3K/Akt is mammalian target of rapamycin (mTOR), which contributes to cell proliferation and angiogenesis. The aim of this study was to investigate the signaling molecules involved in the radio‐sensitizing effects of curcumin on HIMEC subjected to low level of irradiation. We have demonstrated that exposure of HIMEC to low level of irradiation induced mTOR and Akt phosphorylation, which was attenuated by curcumin, rapamycin and LY294002. Activation of NFκB by low level of irradiation was inhibited by curcumin and SN‐50. Curcumin also induced apoptosis by induction of caspase‐3 cleavage in irradiated HIMEC. In conclusion, curcumin significantly inhibited NFκB and attenuated the effect of irradiation‐induced pro‐survival signaling through the PI3k/Akt/mTOR and NFκB pathways in these gut specific endothelial cells. Curcumin may be a potential radio‐sensitizing agent for enhanced anti‐angiogenic effect in colorectal cancer radiation therapy.

GATA3 is a master regulator of the transcriptional response to low-dose ionizing radiation in human keratinocytes

BackgroundThe general population is constantly exposed to low levels of radiation through natural, occupational or medical irradiation. Even if the biological effects of low-level radiation have been intensely debated and investigated, the molecular mechanisms underlying the cellular response to low doses remain largely unknown.ResultsThe present study investigated the role of GATA3 protein in the control of the cellular and molecular response of human keratinocytes exposed to a 1 cGy dose of X-rays. Chromatin immunoprecipitation showed GATA3 to be able to bind the promoter of 4 genes responding to a 1 cGy exposure. To go further into the role of GATA3 after ionizing radiation exposure, we studied the cellular and molecular consequences of radiation in GATA3 knock-down cells. Knock-down was obtained by lentiviral-mediated expression of an shRNA targeting the GATA3 transcript in differentiated keratinocytes. First, radiosensitivity was assessed: the toxicity, in terms of immediate survival (with XTT test), associated with 1 cGy radiation was found to be increased in GATA3 knock-down cells. The impact of GATA3 knock-down on the transcriptome of X-ray irradiated cells was also investigated, using oligonucleotide microarrays to assess changes between 3 h and 72 h post-irradiation in normal vs GATA3 knock-down backgrounds; transcriptome response was found to be completely altered in GATA3 knock-down cells, with a strong induction/repression peak 48 h after irradiation. Functional annotation revealed enrichment in genes known to be involved in chaperone activity, TGFβ signalling and stress response.ConclusionTaken together, these data indicate that GATA3 is an important regulator of the cellular and molecular response of epidermal cells to very low doses of radiation.

Reduced abundance of insects and spiders linked to radiation at Chernobyl 20 years after the accident

Effects of low-level radiation on abundance of animals are poorly known. We conducted standardized point counts and line transects of bumble-bees, butterflies, grasshoppers, dragonflies and spider webs at forest sites around Chernobyl differing in background radiation by over four orders of magnitude. Abundance of invertebrates decreased with increasing radiation, even after controlling for factors such as soil type, habitat and height of vegetation. These effects were stronger when comparing plots differing in radiation within rather than among sites, implying that the ecological effects of radiation from Chernobyl on animals are greater than previously assumed.

Image Gently: improving health literacy for parents about CT scans for children

In a pivotal report issued in 2004 (Health Literacy: A Prescription to End Confusion), the Institute of Medicine discussed the critical need for improved health literacy for the 90 million American adults who have difficulty understanding basic health information. Health literacy is defined as “the degree to which individuals have the capacity to obtain, process, and understand basic information and services needed to make appropriate decisions regarding their health” [1]. The report indicates that “over 300 studies have shown that health information cannot be understood by most people for whom it was intended.” This report stressed the need for a concerted effort by all stakeholders to improve educational opportunities for patients and their families. Patients often have a poor concept of the radiation dose and risk associated with CT [2]. In a study by Larson et al. [3], only 13% of parents understood that there is a theoretical risk that the radiation associated with CT might increase the risk of cancer. Some experts believe that parents may contribute to the increasing demand for CT as they seek rapid diagnosis and decision making without understanding the potential risks [4]. The purpose of this commentary is to discuss the importance of informing caretakers of children undergoing CT examinations about the potential radiation risk and describe some educational tools, developed by the Alliance for Radiation Safety in Pediatric Imaging, that are now available for hospitals, practices, and parents on the Image Gently and American Academy of Pediatrics (AAP) websites. CT is an invaluable diagnostic and management planning tool for health-care providers treating children and adults [5]. Since its introduction in the 1970s, CT use has risen from 2 million studies per year to over 65 million with 7 million CT scans obtained in children in 2007 [6]. The potential radiation risk from CT scans is receiving considerable attention in both the medical literature and lay press [7–11]. The effect of low-level radiation remains controversial with data supporting several differing perspectives [12–15]. Some leading experts propose that low-level radiation has no effect (that there is a threshold below which no harm occurs). Many scientific organizations and experts, however, advocate that radiation even at low levels has a harmful effect and support the concept of a linear, nothreshold model for ionizing radiation risk of cancer induction [16–20]. Because of decreased body fat, increased radiosensitivity and longer life expectancy, children are at increased risk [21–23]. As the true risk from lowPediatr Radiol (2009) 39:112–116 DOI 10.1007/s00247-008-1101-9

微弱放射線の人体への影響. II : リスク評価と原爆線量見直し

微弱放射線の人体への影響. II : リスク評価と原爆線量見直し

Leukaemia incidence in Welsh children linked with low level radiation—making sense ofsome erroneous results published in the media

A series of self-published epidemiological reports purporting to show a major excess risk ofleukaemia in pre-school children living near the Irish Sea coast of Wales have beenpresented in the media as evidence of the harmful effects of low level radiation arising fromSellafield. The Welsh Cancer Intelligence and Surveillance Unit (WCISU), the bodyresponsible for population-based cancer information in Wales, can provide insightsinto the validity of these reports, which appear to be a consequence of variousmistakes. This raises important questions about the research governance of suchreports and the communication of scientific findings via the mass media. Withoutsuitable safeguards the media are in danger of promulgating misinformation.

Health Effects of Low Level Radiation: When will We Acknowledge the Reality?

The 1986 April 26th Chernobyl event was the worst nuclear power accident--it killed 31 people. Its significance was exaggerated immensely because of the pervasive fear of ionizing radiation that has been indoctrinated in all of humanity. In reality, our environment includes radiation from natural sources, varying widely in intensity, to which all living things have adapted. The effect of radiation on organisms is primarily on their damage control biosystem, which prevents, repairs and removes cell damage. Low doses stimulate this system, while high doses inhibit it. So low doses decrease the incidences of cancer and congenital malformations; high doses have the opposite effect. Efforts by radiation protection organizations to lower exposures to (human-made) radiation to as low as reasonably achievable (ALARA) provide no benefit. They only create inappropriate fear-barriers to very important applications of nuclear technology in energy production and medicine.

Species richness and abundance of forest birds in relation to radiation at Chernobyl

The effects of low-level radiation on the abundance of animals are poorly known, as are the effects on ecosystems and their functioning. Recent conclusions from the UN Chernobyl forum and reports in the popular media concerning the effects of radiation from Chernobyl on animals have left the impression that the Chernobyl exclusion zone is a thriving ecosystem, filled with an increasing number of rare species. Surprisingly, there are no standardized censuses of common animals in relation to radiation, leaving the question about the ecological effects of radiation unresolved. We conducted standardized point counts of breeding birds at forest sites around Chernobyl differing in level of background radiation by over three orders of magnitude. Species richness, abundance and population density of breeding birds decreased with increasing level of radiation, even after controlling statistically for the effects of potentially confounding factors such as soil type, habitat and height of the vegetation. This effect was differential for birds eating soil invertebrates living in the most contaminated top soil layer. These results imply that the ecological effects of Chernobyl on animals are considerably greater than previously assumed.

Effect of Low-Level Radiation on the Death of Male Germ Cells

Hormetic and adaptive responses induced by low-level radiation in hematopoietic and immune systems have been observed, as shown by stimulatory effects on cell growth and resistance to subsequent radiation-induced cytogenetic damage. However, in terms of cell death by apoptosis, the effects of low-level radiation are controversial: Some studies showed decreased apoptosis in response to low-level radiation while others showed increased apoptosis. This controversy may be related to the radiation doses or dose rates and also, more importantly, to the cell types. Testes are one of the most radiosensitive organs. The loss of male germ cells after exposure to ionizing radiation has been attributed to apoptosis. In the present study, the effects of low-level radiation at doses up to 200 mGy on mouse male germ cells in terms of apoptosis and the expression of apoptosis-related proteins were examined at different times after whole-body exposure of mice to low-level radiation. In addition, the effect of pre-exposure to low-level radiation on subsequent cell death induced by high doses of radiation was examined to explore the possibility of low-level radiation-induced adaptive response. The results showed that low-level radiation in the dose range of 25-200 mGy induced significant increases in apoptosis in both spermatogonia and spermatocytes, with the maximal effect at 75 mGy. The increased apoptosis is most likely associated with Trp53 protein expression. Furthermore, 75 mGy low-level radiation given pre-irradiation led to an adaptive response of seminiferous germ cells to subsequent high-level radiation-induced apoptosis. These results suggest that low-level radiation induces increased apoptosis in male germ cells but also induces a significant adaptive response that decreases cell death after a subsequent high-dose irradiation.

The Role and Mechanisms of Intercellular Communication and Oxidative Metabolism in the Propagation of Low-Level Radiation Effects

The Role and Mechanisms of Intercellular Communication and Oxidative Metabolism in the Propagation of Low-Level Radiation Effects

Evidence for beneficial low level radiation effects and radiation hormesis

Low doses in the mGy range cause a dual effect on cellular DNA. One is a relatively low probability of DNA damage per energy deposition event and increases in proportion to the dose. At background exposures this damage to DNA is orders of magnitude lower than that from endogenous sources, such as reactive oxygen species. The other effect at comparable doses is adaptive protection against DNA damage from many, mainly endogenous, sources, depending on cell type, species and metabolism. Adaptive protection causes DNA damage prevention and repair and immune stimulation. It develops with a delay of hours, may last for days to months, decreases steadily at doses above about 100 mGy to 200 mGy and is not observed any more after acute exposures of more than about 500 mGy. Radiation-induced apoptosis and terminal cell differentiation also occur at higher doses and add to protection by reducing genomic instability and the number of mutated cells in tissues. At low doses reduction of damage from endogenous sources by adaptive protection maybe equal to or outweigh radiogenic damage induction. Thus, the linear-no-threshold (LNT) hypothesis for cancer risk is scientifically unfounded and appears to be invalid in favour of a threshold or hormesis. This is consistent with data both from animal studies and human epidemiological observations on low-dose induced cancer. The LNT hypothesis should be abandoned and be replaced by a hypothesis that is scientifically justified and causes less unreasonable fear and unnecessary expenditure.