Effects Of Chronic Low-dose Radiation Research Articles

Effects of chronic low-dose radiation on cataract prevalence and characterization in wild boar (Sus scrofa) from Fukushima, Japan

This study evaluated cataracts in wild boar exposed to chronic low-dose radiation. We examined wild boar from within and outside the Fukushima Exclusion Zone for nuclear, cortical, and posterior subcapsular (PSC) cataracts in vivo and photographically. Plausible upper-bound, lifetime radiation dose for each boar was estimated from radioactivity levels in each animal’s home range combined with tissue concentrations of 134+137Cesium. Fifteen exposed and twenty control boar were evaluated. There were no significant differences in overall prevalence or score for cortical or PSC cataracts between exposed and control animals. Nuclear (centrally located) cataracts were significantly more prevalent in exposed boar (p < 0.05) and had statistically higher median scores. Plausible upper-bound, lifetime radiation dose ranged from 1 to 1,600 mGy in exposed animals, with no correlation between dose and cortical or PSC score. While radiation dose and nuclear score were positively associated, the impact of age could not be completely separated from the relationship. Additionally, the clinical significance of even the highest scoring nuclear cataract was negligible. Based on the population sampled, wild boar in the Fukushima Exclusion Zone do not have a significantly higher prevalence or risk of cortical or PSC cataracts compared to control animals.

POLYMORPHISMS IN THE GENES OF REPARATIONS AMONG EMPLOYEES OF THE ATOMIC INDUSTRY OF KAZAKHSTAN

Single nucleotide polymorphisms (SNPs) are the most convenient marker and the widespread subject of polymorphism testing. To identify the presence or absence of the effects of chronic low-dose radiation on nuclear industry personnel, the occurrence of single-nucleotide substitutions at the polymorphic sites of the genes of the repair system 3 and 6 of the introns of the APC gene P53.11 gene, in positions -2549 of the VEGF gene, XPD gene rs313181 ( Lys751Gln) and rs25487 of the XRCC gene (Аrg399Gln) were compared. Analysis of allele frequencies and distribution of genotypes in the variable regions of the tested genes was performed by the method of polymerase chain reaction (PCR), followed by determination of restriction fragment length polymorphism (RFLP). When com-paring the frequencies of alleles and the distribution of genotypes between the second group of miners (11–20 years’ experience) and control, differences in the distribution of genotypes in the rs25487 XRCC plot (χ2 = 7.11, p = 0.028) were revealed. These differences satisfy the criterion p &lt;0.05 and, accordingly, are statistically significant. Key words: polymorphism, genes, a nuclear industry.

Fluorescent coelenteramide-containing protein as a color bioindicator for low-dose radiation effects

The study addresses the application of fluorescent coelenteramide-containing proteins as color bioindicators for radiotoxicity evaluation. Biological effects of chronic low-dose radiation are under investigation. Tritiated water (200MBq/L) was used as a model source of low-intensive ionizing radiation of beta type. 'Discharged obelin,' product of bioluminescent reaction of marine coelenterate Obelia longissimi, was used as a representative of the coelenteramide-containing proteins. Coelenteramide, fluorophore of discharged obelin, is a photochemically active molecule; it produces fluorescence forms of different color. Contributions of 'violet' and 'blue-green' forms to the visible fluorescence serve as tested parameters. The contributions depend on the coelenteramide's microenvironment in the protein, and, hence, evaluate distractive ability and toxicity of radiation. The protein samples were exposed to beta radiation for 18days, and maximal dose accumulated by the samples was 0.28Gy, being close to a tentative limit of a low-dose interval. Increase of relative contribution of 'violet' fluorescence under exposure to the beta irradiation was revealed. High sensitivity of the protein-based test system to low-dose ionizing radiation (to 0.03Gy) was demonstrated. The study develops physicochemical understanding of radiotoxic effects. Graphical abstract Coelenteramide-containing protein (discharged obelin) changes fluorescence color under exposure to low-dose ionizing radiation of tritium.

Hematological Findings in Medical Professionals Involved at Intraoperative Fluoroscopy

&lt;p&gt;Medical professionals involved at intraoperative fluoroscopy are exposed to low doses of the occupational radiation exposures. The biological effects of chronic low-dose radiation on human health are complex and have not been well established. The aim of the present study is to follow up hematological parameter changes during 2 years in medical professionals exposed to ionization radiation in operating rooms.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;22 medical professionals (medical specialists and technicians), chronically exposed to ionizing radiation of mobile C-Arm X ray machine, were selected. The seven hematological parameters were examined each time. The statistical analyses were done by Student’s t test and one way ONOVA test.&lt;/p&gt;&lt;p&gt;The data analysis led to the following observations: (1) the present study incorporated that the basic hematological parameters including the mean value of red blood cells (P=0.90), white blood cells (P=0.68), and platelets count (P=0.45) did not show a significant difference between two years. (2) The mean values corpuscular hemoglobin concentration, corpuscular hemoglobin, and hematocrit parameters were found disturbed low or high in some of medical professionals but their means were not significantly different between two measurements. (3)A statistically significant relation in mean value of RBCs with the duration of exposure and sex were observed.&lt;/p&gt;&lt;p&gt;It seems that, hematological parameters survey could not be a reliable test as the biological indicator of long term exposure to very low dose of radiation exposure in medical professionals which their physical dosimetry values are lower than dose limits. &lt;/p&gt;

Effects of Chronic Low-Dose Radiation on Human Neural Progenitor Cells.

The effects of chronic low-dose radiation on human health have not been well established. Recent studies have revealed that neural progenitor cells are present not only in the fetal brain but also in the adult brain. Since immature cells are generally more radiosensitive, here we investigated the effects of chronic low-dose radiation on cultured human neural progenitor cells (hNPCs) derived from embryonic stem cells. Radiation at low doses of 31, 124 and 496 mGy per 72 h was administered to hNPCs. The effects were estimated by gene expression profiling with microarray analysis as well as morphological analysis. Gene expression was dose-dependently changed by radiation. By thirty-one mGy of radiation, inflammatory pathways involving interferon signaling and cell junctions were altered. DNA repair and cell adhesion molecules were affected by 124 mGy of radiation while DNA synthesis, apoptosis, metabolism, and neural differentiation were all affected by 496 mGy of radiation. These in vitro results suggest that 496 mGy radiation affects the development of neuronal progenitor cells while altered gene expression was observed at a radiation dose lower than 100 mGy. This study would contribute to the elucidation of the clinical and subclinical phenotypes of impaired neuronal development induced by chronic low-dose radiation.

Effects of chronic low-dose radiation on the common reed within the Chernobyl accident Exclusion Zone

The results of the analyses of plant production and parasitic resistance of common reed (Phragmites australis (Cav.) Trin. ex. Steud) from water bodies within the Chernobyl accident exclusion zone are represented. The heavy damage of common reed by the ergot (Claviceps purpurea (Fr.) Tul.) (up to 50%) from water bodies of the left-bank flood lands of the Pripyat River, which is the most contaminated region of the Chernobyl NPP exclusion zone, has been investigated. Deviations in morphological indexes of reproductive organs of common reed from water bodies of right- and left-bank flood lands of the Pripyat River within 10-km exclusion zone are registered. There are: decrease of panicle width, length and flowers number at inflorescence; differences in seed shape and color. The direct correlation between the absorbed dose rate for higher aquatic plants and plant productivity indexes as well as damage events of common reed by the ergot is proved. The parasitic resistance of common reed from water bodies within Chernobyl accident exclusion zone are decreased according to the increase of absorbed dose rate as well.

Methylation changes in muscle and liver tissues of male and female mice exposed to acute and chronic low-dose X-ray-irradiation

The biological and genetic effects of chronic low-dose radiation (LDR) exposure and its relationship to carcinogenesis have received a lot of attention in the recent years. For example, radiation-induced genome instability, which is thought to be a precursor of tumorogenesis, was shown to have a transgenerational nature. This indicates a possible involvement of epigenetic mechanisms in LDR-induced genome instability. Genomic DNA methylation is one of the most important epigenetic mechanisms. Existing data on radiation effects on DNA methylation patterns is limited, and no one has specifically studied the effects of the LDR. We report the first study of the effects of whole-body LDR exposure on global genome methylation in muscle and liver tissues of male and female mice. In parallel, we evaluated changes in promoter methylation and expression of the tumor suppressor gene p16 INKa and DNA repair gene O 6-methylguanine-DNA methyltransferase ( MGMT). We observed different patterns of radiation-induced global genome DNA methylation in the liver and muscle of exposed males and females. We also found sex and tissue-specific differences in p16 INKa promoter methylation upon LDR exposure. In male liver tissue, p16 INKa promoter methylation was more pronounced than in female tissue. In contrast, no significant radiation-induced changes in p16 INKa promoter methylation were noted in the muscle tissue of exposed males and females. Radiation also did not significantly affect methylation status of MGMT promoter. We also observed substantial sex differences in acute and chronic radiation-induced expression of p16 INKa and MGMT genes. Another important outcome of our study was the fact that chronic low-dose radiation exposure proved to be a more potent inducer of epigenetic effects than the acute exposure. This supports previous findings that chronic exposure leads to greater genome destabilization than acute exposure.

Radiation hazard caused by the Chernobyl accident in inhabited areas of Ukraine can be monitored by transgenic plants

The genetic impact of the 1986 accident at the Ukraine Chernobyl Nuclear Power Plant (NPP) on populations of living organisms has yet to be fully assessed. Monitoring of the genotoxicity of polluted soils is a key element in the disaster management program. We used Arabidopsis thaliana and Nicotiana tabacum plants transgenic for a reporter gene revealing homologous recombination to study the genetic effects of chronic low-dose radiation stemming from the soil in inhabited areas of Ukraine where contamination by the accident ranges from 1 to 40 Ci/km 2. We noted a significant dose-dependent increase of homologous recombination in plants cultivated in the affected inhabited areas, proving the persistently high genotoxicity of the radioactively contaminated soils.