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Journal ArticleDOI

Long-term immune and cytogenetic effects of high level natural radiation on Ramsar inhabitants in Iran

TL;DR: Research in Ramsar, a northern coastal city of Iran, has some high level natural radiation areas (HLNRAs) as well as over 50 hot springs with low and high radium contents used as spas by the public and vacationers, and shows significant increase of CD69 expression on TCD4+ stimulated cells and total serum IgE and higher incidence of stable and unstable chromosomal aberrations in the HLNRA group compared to the control group with normal background radiation.
About: This article is published in Journal of Environmental Radioactivity.The article was published on 2004-01-01. It has received 60 citations till now. The article focuses on the topics: Population & Environmental exposure.
Citations
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Journal ArticleDOI
TL;DR: Increased level of chronic low-dose radiation seems to act as a priming dose resulting in the induction of an in vivo radio-adaptive response in elder individuals of the Kerala coast.
Abstract: The present study investigates whether the chronic low-dose radiation exposure induces an in vivo radio-adaptive response in individuals from high-level natural radiation areas (HLNRA) of the Kerala coast. Peripheral blood samples from 54 adult male individuals aged between 26 and 65 years were collected for the study with written informed consent. Each of the whole blood sample was divided into three, one was sham irradiated, second and third was exposed to challenging doses of 1.0 and 2.0 Gy gamma radiation, respectively. Cytokinesis-block micronucleus (CBMN) assay was employed to study the radio-adaptive response. Seventeen individuals were from normal-level natural radiation area (NLNRA ≤1.5 mGy/year) and 37 from HLNRA (> 1.5 mGy/year). Based on the annual dose received, individuals from HLNRA were further classified into low-dose group (LDG, 1.51-5.0 mGy/year, N = 19) and high-dose group (HDG >5.0 mGy/year, N = 18). Basal frequency of micronucleus (MN) was comparable across the three dose groups (NLNRA, LDG and HDG, P = 0.64). Age of the individuals showed a significant effect on the frequency of MN after challenging dose exposures. The mean frequency of MN was significantly lower in elder (>40 years) individuals from HDG of HLNRA as compared to the young (≤40 years) individuals after 1.0 Gy (P 5.0 mGy/year) seems to act as a priming dose resulting in the induction of an in vivo radio-adaptive response in elder individuals of the Kerala coast.

20 citations


Cites background from "Long-term immune and cytogenetic ef..."

  • ...Nevertheless, some of the cytogenetic studies performed in the high background radiation areas of Ramsar have shown increased frequencies of unstable chromosome aberrations (61,62)....

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Journal ArticleDOI
TL;DR: In this paper, a review of the role of epigenetic mechanisms, besides the genetic ones, can have in the responses to low dose and protracted exposures, particularly to natural background radiation.
Abstract: Life has evolved on Earth for about 4 billion years in the presence of the natural background of ionizing radiation. It is extremely likely that it contributed, and still contributes, to shaping present form of life. Today the natural background radiation is extremely small (few mSv/y), however it may be significant enough for living organisms to respond to it, perhaps keeping memory of this exposure. A better understanding of this response is relevant not only for improving our knowledge on life evolution, but also for assessing the robustness of the present radiation protection system at low doses, such as those typically encountered in everyday life. Given the large uncertainties in epidemiological data below 100 mSv, quantitative evaluation of these health risk is currently obtained with the aid of radiobiological models. These predict a health detriment, caused by radiation-induced genetic mutations, linearly related to the dose. However a number of studies challenged this paradigm by demonstrating the occurrence of non-linear responses at low doses, and of radioinduced epigenetic effects, i.e., heritable changes in genes expression not related to changes in DNA sequence. This review is focused on the role that epigenetic mechanisms, besides the genetic ones, can have in the responses to low dose and protracted exposures, particularly to natural background radiation. Many lines of evidence show that epigenetic modifications are involved in non-linear responses relevant to low doses, such as non-targeted effects and adaptive response, and that genetic and epigenetic effects share, in part, a common origin: the reactive oxygen species generated by ionizing radiation. Cell response to low doses of ionizing radiation appears more complex than that assumed for radiation protection purposes and that it is not always detrimental. Experiments conducted in underground laboratories with very low background radiation have even suggested positive effects of this background. Studying the changes occurring in various living organisms at reduced radiation background, besides giving information on the life evolution, have opened a new avenue to answer whether low doses are detrimental or beneficial, and to understand the relevance of radiobiological results to radiation protection.

18 citations

Journal ArticleDOI
01 Feb 2005
TL;DR: It is concluded that more epidemiologic studies are needed before a solid conclusion can be made if a higher incidence or mortality from cancer is seen among the population living in the high-background radiation area of Ramsar.
Abstract: The aim of this study was to investigate if a higher incidence or mortality from cancer is seen among the population living in the high-background radiation area of Ramsar. The Ramsar city was divided into areas of high level of natural radiation area (HLNRA) and normal level of natural radiation area (NLNRA). Data regarding morbidity and mortality from cancer were obtained from different sources. Standard incidence ratios (SIR) were used to compare the morbidity experience of HLNRA to those of NLNRA. Standard mortality ratios (SMR) were calculated for two regions of the HLNRA (low exposure and high exposure) using national mortality rates. The incidence ratio for females was 1.5, indicating a slight increase in incidence in the HLNRA compared with that in the NLNRA. The mortality was slightly higher for females living in HLNRA (SMR=1.3 in high exposure area and 1.2 in low exposure area). Neither SMRs nor SIRs showed a statistically significant difference from the unity. No increase in incidence or mortality was seen among the male population. We have concluded that more epidemiologic studies are needed before a solid conclusion can be made.

15 citations

Journal ArticleDOI
TL;DR: The average annual effective dose on Earth is about 3 mSv, nearly 85% of which comes from natural background radiation, reduced to less than 1mSv if man-made sources and the internal exposure to Rn daughters are excluded.

14 citations

Journal ArticleDOI
TL;DR: It is found that γ-H2AX foci (and thus DNA double strand break) frequency in residents living in the HNBA of Mamuju, West Sulawesi, show a trend towards higher average values relative to the control area, and no statistical difference between man and woman, old and young people in exposed and control area is found.

14 citations

References
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01 Jan 2000
TL;DR: This annex is aimed at providing a sound basis for conclusions regarding the number of significant radiation accidents that have occurred, the corresponding levels of radiation exposures and numbers of deaths and injuries, and the general trends for various practices, in the context of the Committee's overall evaluations of the levels and effects of exposure to ionizing radiation.
Abstract: NOTE The report of the Committee without its annexes appears as Official Records of the General Assembly, Sixty-third Session, Supplement No. 46. The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. The country names used in this document are, in most cases, those that were in use at the time the data were collected or the text prepared. In other cases, however, the names have been updated, where this was possible and appropriate, to reflect political changes. Scientific Annexes Annex A. Medical radiation exposures Annex B. Exposures of the public and workers from various sources of radiation INTROdUCTION 1. In the course of the research and development for and the application of atomic energy and nuclear technologies, a number of radiation accidents have occurred. Some of these accidents have resulted in significant health effects and occasionally in fatal outcomes. The application of technologies that make use of radiation is increasingly widespread around the world. Millions of people have occupations related to the use of radiation, and hundreds of millions of individuals benefit from these uses. Facilities using intense radiation sources for energy production and for purposes such as radiotherapy, sterilization of products, preservation of foodstuffs and gamma radiography require special care in the design and operation of equipment to avoid radiation injury to workers or to the public. Experience has shown that such technology is generally used safely, but on occasion controls have been circumvented and serious radiation accidents have ensued. 2. Reviews of radiation exposures from accidents have been presented in previous UNSCEAR reports. The last report containing an exclusive chapter on exposures from accidents was the UNSCEAR 1993 Report [U6]. 3. This annex is aimed at providing a sound basis for conclusions regarding the number of significant radiation accidents that have occurred, the corresponding levels of radiation exposures and numbers of deaths and injuries, and the general trends for various practices. Its conclusions are to be seen in the context of the Committee's overall evaluations of the levels and effects of exposure to ionizing radiation. 4. The Committee's evaluations of public, occupational and medical diagnostic exposures are mostly concerned with chronic exposures of …

3,924 citations

Journal Article
TL;DR: The risk for high versus low levels of CAs was similar in subjects heavily exposed to carcinogens and in those who had never, to their knowledge, been exposed to any major carcinogenic agent during their lifetime, supporting the idea that chromosome damage itself is involved in the pathway to cancer.
Abstract: An increased risk of cancer in healthy individuals with high levels of chromosomal aberrations (CAs) in peripheral blood lymphocytes has been described in recent epidemiological studies. This association did not appear to be modified by sex, age, country, or time since CA test, whereas the role played by exposure to carcinogens is still uncertain because of the requisite information concerning occupation and lifestyle was lacking. We evaluated in the present study whether CAs predicted cancer because they were the result of past exposure to carcinogens or because they were an intermediate end point in the pathway leading to disease. A nested case-control study was performed on 93 incident cancer cases and 62 deceased cancer cases coming from two prospective cohort studies performed in Nordic countries (Denmark, Finland, Norway, and Sweden) and Italy. For each case, four controls matched by country, sex, year of birth, and year of CA test were randomly selected. Occupational exposure and smoking habit were assessed by a collaborative group of occupational hygienists. Logistic regression models indicated a statistically significant increase in risk for subjects with a high level of CAs compared to those with a low level in the Nordic cohort (odds ratio, 2.35; 95% confidence interval, 1.31-4.23) and in the Italian cohort (odds ratio, 2.66; 95% confidence interval, 1.26-5.62). These estimates were not affected by the inclusion of occupational exposure level and smoking habit in the regression model. The risk for high versus low levels of CAs was similar in subjects heavily exposed to carcinogens and in those who had never, to their knowledge, been exposed to any major carcinogenic agent during their lifetime, supporting the idea that chromosome damage itself is involved in the pathway to cancer. The results have important ramifications for the understanding of the role played by sporadic chromosome damage for the origin of neoplasia-associated CAs.

518 citations


"Long-term immune and cytogenetic ef..." refers background in this paper

  • ...More recently, it has been suggested that chromosome aberration frequency is itself an indicator of cancer risk rather than just a reflection of exposure (Hagmar et al., 1994; Bonassi et al., 2000)....

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Journal Article
TL;DR: An increased level of chromosome breakage appears to be a relevant biomarker of future cancer risk in peripheral blood lymphocytes, according to an ongoing Nordic cohort study of cancer incidence.
Abstract: Cytogenetic assays in peripheral blood lymphocytes (PBL) have been used extensively to survey the exposure of humans to genotoxic agents. The conceptual basis for this has been the hypothesis that the extent of genetic damage in PBL reflects critical events for carcinogenic processes in target tissues. Until now, no follow-up studies have been performed to assess the predictive value of these methods for subsequent cancer risk. In an ongoing Nordic cohort study of cancer incidence, 3182 subjects were examined between 1970 and 1988 for chromosomal aberrations (CA), sister chromatid exchange or micronuclei in PBL. In order to standardize for the interlaboratory variation, the results were trichotomized for each laboratory into three strata: low (1-33 percentile), medium (34-66 percentile), or high (67-100 percentile). In this second follow-up, a total of 85 cancers were diagnosed during the observation period (1970-1991). There was no significant trend in the standardized incidence ratio with the frequencies of sister chromatid exchange or micronuclei, but the data for these parameters are still too limited to allow firm conclusions. There was a statistically significant linear trend (P = 0.0009) in CA strata with regard to subsequent cancer risk. The point estimates of the standardized incidence ratio in the three CA strata were 0.9, 0.7, and 2.1, respectively. Thus, an increased level of chromosome breakage appears to be a relevant biomarker of future cancer risk.

510 citations


"Long-term immune and cytogenetic ef..." refers background in this paper

  • ...More recently, it has been suggested that chromosome aberration frequency is itself an indicator of cancer risk rather than just a reflection of exposure (Hagmar et al., 1994; Bonassi et al., 2000)....

    [...]

Journal ArticleDOI
TL;DR: Current understanding of the mechanisms involved in IgE regulation are summarized in this paper, which is of primary importance in defining alterations responsible for the pathological conditions characterized by hyperproduction of IgE.

255 citations


"Long-term immune and cytogenetic ef..." refers background in this paper

  • ...Romagnani (1990) reported that the Th2 lymphocytes are more radioresistant than other lymphocytes and IL-4 produced by these cells, enhance IgE production....

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