scholarly journals Evaluation of Global DNA Methylation and Gene Expression of Izumo1 and Izumo1r in Gonads after High- and Low-Dose Radiation in Neonatal Mice

Biology ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1270
Author(s):  
Akifumi Nakata ◽  
Keisuke Sato ◽  
Yohei Fujishima ◽  
Valerie Goh Swee Ting ◽  
Kanade Nakayama ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Ionizing Radiation ◽  
Methylation Level ◽  
Low Dose ◽  
Control Group ◽  
Global Dna Methylation ◽  
Low Dose Radiation ◽  
Methylation Patterns ◽  
Dose Radiation

The intergenerational effects from chronic low-dose exposure are matters of concern. It is thus important to elucidate the radiation-induced effects of germ cell maturation, fertilization and embryonic development. It is well known that DNA methylation levels in CpG sites in gametes are reprogrammed in stages during their maturity. Furthermore, the binding of Izumo on the surface of sperm and Juno on the surface of oocytes is essential for fertilization. Thus, there is a possibility that these genes are useful indicators to evaluate fertility in mice after irradiation exposure. Therefore, in this study, we analyzed global DNA methylation patterns in the testes and gene expression of Izumo1 and Izumo1r (Juno) in the gonads of mice after neonatal acute high-dose ionizing radiation (HDR) and chronic low-dose ionizing radiation (LDR). One-week-old male and female mice were irradiated with a total dose of 4 Gy, with acute HDR at 7 days at a dose rate of 30 Gy/h and LDR continuously at a dose rate of 6 mGy/h from 7 to 35 days. Their gonads were subsequently analyzed. The results of global DNA methylation patterns in the testes showed that methylation level increased with age in the control group, the LDR group maintained its DNA methylation level, and the HDR group showed decreased DNA methylation levels with age. In the control group, the gene expression level of Izumo1 in the testis did not show age-related changes, although there was high expression at 100 days of age. However, in the LDR group, the expression level recovered after the end of irradiation, while it remained low regardless of age in the HDR group. Conversely, gene expression of Izumo1r (Izumo1 receptor) in the ovary decreased with age in the control group. Although the gene expression of Izumo1r decreased with age in the LDR group, it remained low in the HDR group. Our results indicate that LDR can induce different DNA methylation patterns, and both high- and low-dose radiation before sexual maturity might affect gametogenesis and fertility.

scholarly journals A systematic review on the effect of low-dose radiation on hearing

2021 ◽  
Author(s):  
Srikanth Nayak ◽  
Arivudai Nambi ◽  
Sathish Kumar ◽  
P Hariprakash ◽  
Pradeep Yuvaraj ◽  
...  
Keyword(s):  
Systematic Review ◽  
Ionizing Radiation ◽  
Radiation Exposure ◽  
Low Dose ◽  
Behavioral Symptoms ◽  
National Council ◽  
Low Dose Radiation ◽  
Cochlear Function ◽  
High Frequencies ◽  
Dose Radiation

AbstractNumerous studies have documented the adverse effects of high-dose radiation on hearing in patients. On the other hand, radiographers are exposed to a low dose of ionizing radiation, and the effect of a low dose of radiation on hearing is quite abstruse. Therefore, the present systematic review aimed to elucidate the effect of low-dose ionizing radiation on hearing. Two authors independently carried out a comprehensive data search in three electronic databases, including PUBMED/MEDLINE, CINAHL, and SCOPUS. Eligible articles were independently assessed for quality by two authors. Cochrane Risk of Bias tool was used assess quality of the included studies. Two articles met the low-dose radiation exposure criteria given by Atomic Energy Regulatory Board (AERB) and National Council on Radiation Protection (NCRP) guidelines. Both studies observed the behavioral symptoms, pure-tone hearing sensitivity at the standard, extended high frequencies, and the middle ear functioning in low-dose radiation-exposed individuals and compared with age and gender-matched controls. One study assessed the cochlear function using transient-evoked otoacoustic emissions (TEOAE). Both studies reported that behavioral symptoms of auditory dysfunction and hearing thresholds at extended high frequencies were higher in radiation-exposed individuals than in the controls. The current systematic review concludes that the low-dose ionizing radiation may affect the hearing adversely. Nevertheless, further studies with robust research design are required to explicate the cause and effect relationship between the occupational low-dose ionizing radiation exposure and hearing.

scholarly journals Phosphoprotein profiles of candidate markers for early cellular responses to low-dose γ-radiation in normal human fibroblast cells

2017 ◽  
Vol 58 (3) ◽  
pp. 329-340 ◽  
Author(s):  
Ji-Hye Yim ◽  
Jung Mi Yun ◽  
Ji Young Kim ◽  
In Kyung Lee ◽  
Seon Young Nam ◽  
...  
Keyword(s):  
Ionizing Radiation ◽  
Human Fibroblast ◽  
Low Dose ◽  
High Dose ◽  
Normal Human Fibroblast ◽  
Low Dose Radiation ◽  
Γ Radiation ◽  
Normal Human ◽  
Dose Radiation ◽  
In Cells

Abstract Ionizing radiation causes biological damage that leads to severe health effects. However, the effects and subsequent health implications caused by exposure to low-dose radiation are unclear. The objective of this study was to determine phosphoprotein profiles in normal human fibroblast cell lines in response to low-dose and high-dose γ-radiation. We examined the cellular response in MRC-5 cells 0.5 h after exposure to 0.05 or 2 Gy. Using 1318 antibodies by antibody array, we observed ≥1.3-fold increases in a number of identified phosphoproteins in cells subjected to low-dose (0.05 Gy) and high-dose (2 Gy) radiation, suggesting that both radiation levels stimulate distinct signaling pathways. Low-dose radiation induced nucleic acid–binding transcription factor activity, developmental processes, and multicellular organismal processes. By contrast, high-dose radiation stimulated apoptotic processes, cell adhesion and regulation, and cellular organization and biogenesis. We found that phospho-BTK (Tyr550) and phospho-Gab2 (Tyr643) protein levels at 0.5 h after treatment were higher in cells subjected to low-dose radiation than in cells treated with high-dose radiation. We also determined that the phosphorylation of BTK and Gab2 in response to ionizing radiation was regulated in a dose-dependent manner in MRC-5 and NHDF cells. Our study provides new insights into the biological responses to low-dose γ-radiation and identifies potential candidate markers for monitoring exposure to low-dose ionizing radiation.

Hiatus in Infant Acute Leukemia Incidence rates in Belarus: Adaptation-to-Low-Dose-Radiation Phenomenon?

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 507-507
Author(s):  
Vadim Ivanov ◽  
Tatiana Terehovich ◽  
Eugene Ivanov
Keyword(s):  
Ionizing Radiation ◽  
Acute Leukemia ◽  
Radiation Exposure ◽  
Low Dose ◽  
Incidence Rates ◽  
Low Dose Radiation ◽  
Infant Leukemia ◽  
Dose Radiation ◽  
Group 1

Abstract Abstract 507 The question of whether child acute leukemia (ChAL) incidence has changed as a result of Chernobyl is of great scientific and public interest. Our initial report (Nature, 1993) showed no increase in the incidence rates (IR) of ChAL in Belarus in the whole group of children (0–14 y.o.) 5 years (1986 – 1991) after accident. This data were confirmed in several European countries. As concerns infant's AL (0–1 y.o.), Petridou et al. reported 2.6 times increase of AL in Greek infants, exposed in utero to Chernobyl radiation. No significant difference in IR was found among children aged 1 – 4 y.o. or older. All epidemiological data concerning separate analysis of infant (0–1 y.o.) ChL was concentrated on the first decade after Chernobyl and no any systematic data is available after 1996. Since 1979 the occurrence of leukemia has been documented accurately through the Registry of Blood diseases. The patients had to be inhabitants of Belarus and were grouped by age at diagnosis. AL diagnostic accuracy was confirmed by the international experts. Rates were standardized directly to the standard world population. We present the age-cohort-period analyses of IR trends of ChAL from 1979 to 2006 in Belarus. It comprised 1077 ChAL cases (0–4 y.o.). Number of cases and equivalent doses of whole body radiation exposure was tabulated by age at diagnosis and period of observation (seven pre-accident years, 1979–1985) and post-accident 7-year periods: 1986–1992, 1993–1999 and 2000–2006. During first 7 years after the accident (1986–1992) the IR of infant AL (0–1 y.o.) increased significantly – from 49 (IR=4.33) before Chernobyl to 67 cases (IR=6.36) in 1986–1992 (RR=1.47; p=0.04). Older age group (1–4 y.o.) did not show any increase in ChAL rates. Following 7-years period (1993–1999) revealed the statistically significant decrease of incidence of infant leukemia: from 49 (IR=4.33) before Chernobyl to 16 cases (IR=2.29) in 1993–1999 years (RR=0.53; p=0.024). Surprisingly, during the next 7 years (2000–2006) we found a further decrease of the incidence of infant leukemia with only 3 cases (IR=0.47) in 7 years. It is highly significant when compared with 49 cases (IR=4.33) before Chernobyl (p= 0.0000053, RR=0.11) and 67 cases (IR=6.36) appeared during first 7 years following Chernobyl accident (p < 0.0000001, RR=0.04). As concerns the older group (1–4 y.o.) we did not find any decrease of IR into the second (1993–1999) and third (2000–2006) 7-year periods. Actually we are working on the next time period (2007–2010) and new upgraded data will be presented. Long-term analysis of incidence of post-Chernobyl childhood acute leukemia permitted to discover the biphasic dynamics of infant's AL incidence rate. Significant increase into the first 7-year period followed by dramatic decrease between year +8 and year + 21. From radiological point of view it is relatively simpler to explain the increase into the first 7 years, because ionizing radiation is one of the few exposures for which the casual relationship with childhood leukemia has been established. Much more difficult to explain following after decrease in incidence rate of infant leukemia in Belarus. Can we speculate about the “adaptation-to-radiation” mechanisms? Over the past decades the growing body of data from cell cultures, experimental animals and humans suggests that low-dose ionizing radiation may have some beneficial (hormetic or adoptive) effect. Several epidemiological studies (India, China, Japan, USA) of a long-term low dose environmental irradiation are in favor of the hypothesis of radiation hormesis or adaptation. The carcinogenic effects of low dose radiation exposure may be restricted to children exposed in utero or in early infancy (0-12 months) during the first years after explosion. Following after dramatic decrease of IRs of infant leukemia might be explained by the developing of adaptive response to chronic low dose ionizing radiation exposure. The presented data may be one of the first clinical evidence concerning human ability of adaptation to long-term low dose radiation. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Changing Attitude Toward Radiation Carcinogenesis and Prospects for Novel Low-Dose Radiation Treatments

2016 ◽  
Vol 15 (6) ◽  
pp. 732-736 ◽  
Author(s):  
Yehoshua Socol ◽  
James S. Welsh
Keyword(s):  
Ionizing Radiation ◽  
Low Dose ◽  
Epidemiological Studies ◽  
International Commission ◽  
Radiation Hazard ◽  
Radiological Protection ◽  
Low Doses ◽  
Low Dose Radiation ◽  
Radiation Treatments ◽  
Dose Radiation

All procedures involving ionizing radiation, whether diagnostic or therapeutic, are subject to strict regulation, and public concerns have been raised about even the low levels of radiation exposures involved in diagnostic imaging. During the last 2 decades, there are signs of more balanced attitude to ionizing radiation hazards, as opposed to the historical “radiophobia.” The linear no-threshold hypothesis, based on the assumption that every radiation dose increment constitutes increased cancer risk for humans, is increasingly debated. In particular, the recent memorandum of the International Commission on Radiological Protection admits that the linear no-threshold hypothesis predictions at low doses (that International Commission on Radiological Protection itself has used and continues to use) are “speculative, unproven, undetectable, and ‘phantom’.” Moreover, numerous experimental, ecological, and epidemiological studies suggest that low doses of ionizing radiation may actually be beneficial to human health. Although these advances in scientific understanding have not yet yielded significant changes in radiation regulation and policy, we are hopeful such changes may happen in the relatively near future. This article reviews the present status of the low-dose radiation hazard debate and outlines potential opportunities in the field of low-dose radiation therapy.

scholarly journals Five-year post-disaster mental changes: Mothers and children living in low-dose contaminated Fukushima regions

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243367
Author(s):  
Yuji Tsutsui ◽  
Tatsuo Ujiie ◽  
Rieko Takaya ◽  
Misako Tominaga
Keyword(s):  
Radiation Protection ◽  
Low Dose ◽  
Psychological Symptoms ◽  
Psychological Effects ◽  
Control Group ◽  
Low Dose Radiation ◽  
Fukushima Prefecture ◽  
Mothers And Children ◽  
Fukushima Daiichi ◽  
Dose Radiation

It has been almost 10 years since the accident at Tokyo Electric Power Co., Inc.’s Fukushima Daiichi Nuclear Power Plant in March 2011. This study elucidates changes in the mental states of mothers and children residing in low-dose radiation contaminated regions within Fukushima Prefecture over a five-year period after the Fukushima Daiichi accident. From 2011 to 2015, questionnaire surveys assessing psychological symptoms, including posttraumatic stress disorder-related responses, depressive responses, and stress responses, and radiation protection behaviors were conducted with 18,741 mothers of children aged four, 18, and 42 months. Mothers’ and children’s psychological symptoms and mothers’ radiation protection behaviors were highest in 2011, immediately following the nuclear accident, but decreased over time. However, even in 2015, psychological symptoms and radiation protection behaviors were higher for children and mothers within Fukushima Prefecture than for those in a control group living in regions outside the area, which were minimally affected by the accident. The results suggest that the psychological effects in mothers and children living in low-dose radiation contaminated areas continued for at least five years after the accident. Furthermore, psychological effects in children born after the incident were likely to have been triggered by the parental behavior of mothers who were negatively affected by anxiety and stress. This finding raises concerns regarding the accident’s long-lasting psychological effects in mothers and children living in low-contamination regions.

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