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Radiation hormesis

Shilpa Sharma, Neha Singla, Vijayta Dani Chadha, D K Dhawan
OBJECTIVE: The concept of radiation hormesis has been the matter of discussion with regard to beneficial effects to biological systems from low doses of ionizing radiations. However, its molecular basis is not well understood till now and the present study is a step forward to elucidate how low levels of ionizing radiation prove beneficial for functioning of biological systems. MATERIAL AND METHODS: Female Wistar rats weighing 100-120g were divided into four different groups...
March 5, 2019: Hellenic Journal of Nuclear Medicine
Bill Sacks, Gregory Meyerson
The linear no-threshold assumption misunderstands the complex multiphasic biological response to ionizing radiation, focusing solely on the initial physical radiogenic damage. This misunderstanding is enabled (masked and amplified) by a number of mathematical approaches that bias results in favor of linear no-threshold and away from alternatives, like hormesis, that take biological response into account. Here we explore a number of these mathematical approaches in some detail, including the use of frequentist rather than Bayesian statistical rules and methods...
February 14, 2019: Health Physics
Witawat Jangiam, Chatchanok Udomtanakunchai, Paiboon Reungpatthanaphong, Montree Tungjai, Louise Honikel, Chris R Gordon, Kanokporn Noy Rithidech
We used 3 biological metrics highly relevant to health risks, that is, cell death, inflammation, and global DNA methylation, to determine the late effects of low doses (0.05 or 0.1 Gy) of 137 Cs γ rays on the bone marrow, lung, and testis collected at 6 months post-irradiation from the same exposed BALB/cJ mouse. This integrative approach has not been used for such a purpose. Mice exposed to 0 or 1 Gy of radiation served as a sham or positive control group, respectively. The results could deliver information for better health risk assessment across tissues, including better scientific basis for radiation protection and clinical application...
October 2018: Dose-response: a Publication of International Hormesis Society
Jerry M Cuttler
In 1958, Neil Wald presented data on the incidence of leukemia among the Hiroshima atomic bomb survivors. These data, which suggested a dose-response threshold for radiation-induced leukemia, were included in the first UNSCEAR report (1958). However, this evidence of a threshold was not recognized. It was obfuscated and concealed. In 2010, Zbigniew Jaworowski identified these data as evidence of radiation hormesis. A letter to the editor in 2014 and 2 articles in 2014 and 2015 presented a graph of these UNSCEAR 1958 data, which revealed a threshold at about 500 mSv...
October 2018: Dose-response: a Publication of International Hormesis Society
M Nikolaishvili, S Omiadze, T Shishniashvili, D Zurabashvili, G Parulava
Supersaturation of hydroxyapatite is very important in order to preserve the homeostasis of mineral metabolism in the oral cavity. This indicates to the ability of saliva to preserve the homeostasis of the tooth tissues. So it is very important to use inhalations and rinses with Tskhaltubo mineral water. It is the alpha radiation of radon contained in the water of Tskhaltubo that plays a very important role in the regulation of inflammatory processes and the preservation of homeostasis of the oral cavity. A lot of works have been published lately proving that these doses are characterized by the so-called "hormesis", so the object of our interest is to determine the mechanism of radon hormesis and its effects on preserving the homeostasis of mineral metabolism in the oral cavity...
September 2018: Georgian Medical News
Shizuyo Sutou, Akiko Koeda, Kana Komatsu, Toshiyuki Shiragiku, Hiroshi Seki, Kohji Yamakage, Takeru Niitsuma, Toshiyuki Kudo, Akihiro Wakata
Background: According to the linear no-threshold model (LNT), even the smallest amount of radiation is hazardous. Although the LNT is not based on solid data, this hypothesis has been applied to mutagens and carcinogens. As a result, it has been postulated that there are no thresholds for these chemicals. To demonstrate negativity by experiments is practically impossible, because negative data may leave behind the possibility that additional data might make the resolution power high enough to change negativity to positivity...
2018: Genes and Environment: the Official Journal of the Japanese Environmental Mutagen Society
Mohan Doss
The linear no-threshold (LNT) model for radiation-induced cancer was adopted by national and international advisory bodies in the 1950s, and has guided radiation protection policies worldwide since then. The resulting strict regulations have increased the compliance costs for the various uses of radiation including nuclear medicine. The concerns regarding low levels of radiation due to the absence of threshold has also resulted in adverse consequences. The LNT model was justified based on the concepts that low levels of radiation increase mutations, and increased mutations imply increased cancers...
September 27, 2018: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
Alexander M Shephard, Vadim Aksenov, Jonathan Tran, Connor J Nelson, Douglas R Boreham, C David Rollo
Exposure to low-dose ionizing radiation can have positive impacts on biological performance-a concept known as hormesis. Although radiation hormesis is well-documented, the predominant focus has been medical. In comparison, little research has examined potential effects of early life radiation stress on organismal investment in life history traits that closely influence evolutionary fitness (eg, patterns of growth, survival, and reproduction). Evaluating the fitness consequences of radiation stress is important, given that low-level radiation pollution from anthropogenic sources is considered a major threat to natural ecosystems...
July 2018: Dose-response: a Publication of International Hormesis Society
P Dvorák, J Doležalová, P Suchý, E Straková, D Zapletal, V Rulík
In our experiment, we deal with the phenomenon of radiation hormesis and improvements based on this phenomenon to different growing characteristics of the fast-growing, very feed-efficient, and with a high-yielding carcass hybrid of the Peking duck (Cherry Valley SM3 medium).In the first phase of the project, we exposed hatching duck eggs to low and middle doses of gamma radiation 60Co (0.06-2.00 Gy) before placing them into a setter in the hatchery. We then followed the standards of artificial incubation...
August 30, 2018: Poultry Science
Sudha Sajeev, Jose Savio Melo, Smitha Hegde
Pityrogramma calomelanos (L.) Link, popularly known as "Silver fern" has significant importance as a medicinal plant used traditionally for its astringent, analgesic, anti-haemorrhagic, anti-hypertensive, anti-pyretic and anthelminthic properties. This fern demonstrates an increased morphogenetic potential towards sporophyte formation, upon exposure to low doses of gamma radiation. Young sporophytic leaf crosier cultures were established in vitro on agar based Knop's media with and without 20 g/l sucrose...
August 13, 2018: Bio Systems
Yuta Shibamoto, Hironobu Nakamura
The effects of low-dose radiation are being increasingly investigated in biological, epidemiological, and clinical studies. Many recent studies have indicated the beneficial effects of low doses of radiation, whereas some studies have suggested harmful effects even at low doses. This review article introduces various studies reporting both the beneficial and harmful effects of low-dose radiation, with a critique on the extent to which respective studies are reliable. Epidemiological studies are inherently associated with large biases, and it should be evaluated whether the observed differences are due to radiation or other confounding factors...
August 13, 2018: International Journal of Molecular Sciences
Simona Gaetani, Federica Monaco, Massimo Bracci, Veronica Ciarapica, Giulia Impollonia, Matteo Valentino, Marco Tomasetti, Lory Santarelli, Monica Amati
OBJECTIVE: Medical personnel using radiation for diagnosis and therapeutic purposes are potentially at risk of cancer development. In this study, the effect of ionising radiation (IR) exposure was evaluated as DNA damage response (DDR) in the circulating cells of occupationally exposed subjects. METHODS: The study population consisted of IR-exposed workers included both in group B (effective dose ranging between 0.04 and 6 mSv/year) and group A (probable effective dose exceeding 6 mSv/year), and the control group consisted of healthy individuals who had never been occupationally exposed to IR or other known carcinogenic agents...
October 2018: Occupational and Environmental Medicine
György Csaba
The hormesis concept demonstrates that in contrast to the toxic effect of high doses of materials, irradiation, etc., low doses of them are beneficial and, in addition, help to eliminate (prevent) the deleterious effect of high doses given after it. By this effect, it is an important factor of (human) evolution protecting man from harmful impacts, similarly to the role of immunity. However, immunity is also continuously influenced by hormetic effects of environmental [chemical (pollutions), physical (background irradiations and heat), etc...
July 17, 2018: Acta Microbiologica et Immunologica Hungarica
Paul A Oakley, Deed E Harrison
Evidence-based contemporary spinal rehabilitation often requires radiography. Use of radiography (X-rays or computed tomography scans) should not be feared, avoided, or have their exposures lessened to decrease patient dose possibly jeopardizing image quality. This is because all fears of radiation exposures from medical diagnostic imaging are based on complete fabrication of health risks based on an outdated, invalid linear model that has simply been propagated for decades. We present 7 main arguments for continued use of radiography for routine use in spinal rehabilitation: (1) the linear no-threshold model for radiation risk estimates is invalid for low-dose exposures; (2) low-dose radiation enhances health via the body's adaptive response mechanisms (ie, radiation hormesis); (3) an X-ray with low-dose radiation only induces 1 one-millionth the amount of cellular damage as compared to breathing air for a day; (4) radiography is below inescapable natural annual background radiation levels; (5) radiophobia stems from unwarranted fears and false beliefs; (6) radiography use leads to better patient outcomes; (7) the risk to benefit ratio is always beneficial for routine radiography...
April 2018: Dose-response: a Publication of International Hormesis Society
S V Jargin
Hormesis can be explained by evolutionary adaptation to the current level of a factor present in the natural environment or to some average from the past. This pertains also to ionizing radiation as the natural background has been decreasing during the time of the life existence. DNA damage and repair are normally in a dynamic balance. The conservative nature of the DNA repair suggests that cells may have retained some capability to repair damage from higher radiation levels than that existing today. According to this concept, the harm caused by radioactive contamination would tend to zero with a dose rate tending to a wide range level of the natural radiation background...
January 1, 2018: Human & Experimental Toxicology
Lei Zhou, Xiaoying Zhang, Hui Li, Chao Niu, Dehai Yu, Guozi Yang, Xinyue Liang, Xue Wen, Min Li, Jiuwei Cui
Although low-dose radiation (LDR) possesses the two distinct functions of inducing hormesis and adaptive responses, which result in immune enhancement and tumor inhibition, its clinical applications have not yet been elucidated. The major obstacle that hinders the application of LDR in the clinical setting is that the mechanisms underlying induction of tumor inhibition are unclear, and the risks associated with LDR are still unknown. Thus, to overcome this obstacle and elucidate the mechanisms mediating the antitumor effects of LDR, in this study, we established an in vivo lung cancer model to investigate the participation of the immune system in LDR-induced tumor inhibition and validated the pivotal role of the immune system by impairing immunity with high-dose radiation (HDR) of 1 Gy...
April 2018: Cancer Medicine
Nan Yu, Sinian Wang, Xiujun Song, Ling Gao, Wei Li, Huijie Yu, Chuanchuan Zhou, Zhenxia Wang, Fengsheng Li, Qisheng Jiang
For dendritic cells (DCs) to initiate an immune response, their ability to migrate and to produce interleukin-12 (IL-12) is crucial. It has been previously shown that low-dose radiation (LDR) promoted IL-12 production by DCs, resulting in increased DC activity that contributed to LDR hormesis in the immune system. However, the molecular mechanism of LDR-induced IL-12 production, as well as the effect of LDR on DC migration capacity require further elucidation. Using the JAWSII immortalized mouse dendritic cell line, we showed that in vitro X-ray irradiation (0...
April 2018: Radiation Research
Se-A Kim, Yu-Mi Lee, Je-Yong Choi, David R Jacobs, Duk-Hee Lee
Although the toxicity of synthetic chemicals at high doses is well known, chronic exposure to low-dose chemical mixtures has only recently been linked to many age-related diseases. However, it is nearly impossible to avoid the exposure to these low-dose chemical mixtures as humans are exposed to a myriad of synthetic chemicals as a part of their daily lives. Therefore, coping with possible harms due to low dose chemical mixtures is challenging. Interestingly, within the range of environmental exposure, disease risk does not increase linearly with increasing dose of chemicals, but often tends to plateau or even decrease with increasing dose...
February 2018: Environmental Pollution
Si-Jie Li, Xin-Yue Liang, Hai-Jun Li, Guo-Zi Yang, Wei Li, Zhuo Li, Lei Zhou, Xue Wen, De-Hai Yu, Jiu-Wei Cui
Low-dose ionizing radiation (LDIR) induces hormesis, exerts an adoptive effect on normal mammalian cells and stimulates cell proliferation; however, this effect is absent in cancer cells. Little is known on the molecular mechanisms underlying this differential response between normal and cancer cells. In the present study, it was demonstrated that the human prostate cancer cell line PC-3 and the normal prostate cell line RWPE-1 exhibited differential biological responses to LDIR. Through cell cycle analyses, it was demonstrated that LDIR inhibited cell growth and arrested the cell cycle at the S and G2/M phases in PC-3 cells, but not in RWPE-1 cells...
January 2018: International Journal of Molecular Medicine
Ahmed Hamarsheh, Ahmad Amro
This study investigated 94.4% of Palestinian radio technologists and the mean percentage of correct answers for knowledge and awareness questions was 26.4%. The percentage of correct answers for questions testing knowledge of the ALARA (As Low As Reasonably Achievable) principle and hormesis hypothesis was 66.5% and 17.2%, respectively. Radio technologists with education level higher than bachelor degree and < 5 years' work experience showed a significantly higher level of knowledge. The most radiosensitive organs were correctly identified as the lungs and stomach by 6...
October 30, 2017: Eastern Mediterranean Health Journal
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