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One of the most harmful DNA lesions brought on by exposure to ionizing radiation (IR) is DNA double-strand breaks. The working duration time may affect the dose accumulation of radiation workers routinely exposed to IR. The study presented here aims to determine the correlation between micronuclei (MN) frequency and γ-H2AX foci index in medical workers who are occupationally exposed to low-dose IR. Peripheral blood lymphocytes were collected from 30 radiation workers that grouped working less and more than 20 years, consisting of radiologists, nurses, cardiologists and radiology technicians. MN frequencies were calculated by analysing 1000 binucleated cells and γ-H2AX foci were calculated by analysing 50 cells. No significant difference was observed between the γ-H2AX foci frequencies and MN indexes when comparing the exposed group with working years ≥20 compared to those working

Objective: The purpose of this study was to analyze the effect of oral administration of radioiodine (I-131) on the immune responses (interleukin 6 and 10) as biodosimetry markers and to support clinical trials of I-131 solution., Methods: The design of this study was an in vivo experimental study using twenty-seven male rats (Rattus norvegicus strain Sprague-Dawley) given 100 μL of I-131 solution at a dose of 260 μCi. Blood plasma was taken at 0.25, 0.5, 1, 3, 24, 48, 120, and 168 hours post oral I-131 administration, respectively. Rats without radioiodine administration as a control group. The levels of IL-6 and IL-10 were measured using the enzyme-linked immunosorbent assay (ELISA) method. Statistical analysis was carried out with one-way ANOVA using SPSS version 25 software., Result: IL-6 level began to significantly increase at 0.25 hours post administration of I-131 (14.4 pg/mL ± 2.52 pg/mL, p=0.02). During 7 days of observation, IL-6 levels had 2 peaks of highly significant increase at 0.5 hours (43.57 ± 5.28, p<0.001) and 120 hours (24.08 ± 2.69, p<0.001 compared to control (5.44 ± 0.95 pg/mL). IL-10 level began to significantly increase at 0.25 hours (30.32 ± 3.22 pg/mL, p=0.03) compared to controls (20.61 ± 1.59 pg/mL)., Conclusion: The highest increase in IL-6 and IL-10 levels occurred respectively in the first 0.5 hours 8 times and in the first 0.25 hours 1.47 times compared to controls. Internal irradiation with radioiodine resulted in a significant increase in immune cells in exposed blood plasma characterized by the production of the cytokines IL-6 and IL-10. This appears to be a response of immune cells to reduce or stop inflammatory reactions through the release of anti-inflammatory cytokines in an effort to prevent excessive inflammatory responses that can damage cells and tissues.

In the event of a radiological incident, a fast and accurate biological dosimetry (biodosimetry) method for evaluating people who have been potentially exposed to ionising radiation is crucial. Among the many biodosimetry methods available, the immunodetection of phosphorylated H2AX (γ-H2AX) stands as a promising method to be used in the triage of patients exposed to radiation. Currently, the most common way to measure γ-H2AX levels is through fluorescence microscopy. In this pilot study, we assessed the feasibility of using an enzyme-linked immunosorbent assay (ELISA) for quantifying γ-H2AX for biodosimetry purposes. Moreover, the usefulness of measuring phosphorylated ATM (pATM) levels through ELISA for biodosimetry was also evaluated. Blood samples were obtained from three male donors (38 y) and were irradiated with 60Co (0, 1, 2 and 6 Gy). Peripheral blood mononuclear cells (PBMCs) were isolated and lysed before measuring γ-H2AX, total H2AX protein and pATM using ELISA kits. The dicentric chromosome assay (DCA) using whole blood was also performed for comparison. Data from all donors at each dose were pooled before statistical analysis. The ratio of γ-H2AX/total H2AX and pATM levels increased in a radiation-dose-dependent manner. The average γ-H2AX/total H2AX ratios were 0.816 ± 0.219, 0.830 ± 0.685, 1.276 ± 1.151 and 1.606 ± 1.098, whereas the average levels of pATM were 59.359 ± 3.740, 63.366 ± 0.840, 66.273 ± 2.603 and 69.936 ± 4.439, in PBMCs exposed to 0, 1, 2 and 6 Gy, respectively. The linear-quadratic dose-response calibration curve for DCA was Y = 0.0017 (±0.0010) + 0.0251 (±0.0142) × D + 0.0342 (±0.0039) × D2  $\boldsymbol{Y}=\mathbf{0.0017}\left(\pm \mathbf{0.0010}\right)+\mathbf{0.0208}\left(\pm \mathbf{0.0218}\right)\times \boldsymbol{D}+\mathbf{0.0350}\left(\pm \mathbf{0.0050}\right)\times{\boldsymbol{D}}^{\mathbf{2}}$. Overall, despite a large variability in the ratio of γ-H2AX/total H2AX among donors, the present study revealed the suitability of using the ratio of γ-H2AX/total H2AX and pATM for biodosimetry. Still, more research with a larger group of subjects is necessary to construct a reliable calibration curve for the ratio of γ-H2AX/total H2AX and pATM levels for biodosimetry., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Objective: The purpose of this study was to assess the immune response and malondialdehyde levels in irradiated rats supplemented with Curcuma xanthorriza Roxb extract as a candidate for mitigating radiation exposure., Methods: Twenty-four male Wistar rats were grouped into eight treatment groups, then Curcuma xanthorrhiza Roxb extract was administered orally and irradiated at 6 Gy. Measurement of rats IL-6 and INF-γ was performed using a sandwich ELISA Kit, while the MDA concentration was quantified according to the method of Wills (1971). The statistical test is determined by one way ANOVA test. P-value <0.05 was considered statistically significant., Result: The concentration of IL-6 in all groups showed no statistically significant difference (P=0.18). There was an increase in the concentration of IL-6 in the group of rats irradiated with 6 Gy for 7 days and 14 days. Meanwhile, the INF-γ concentration also showed no significant results in all treatment groups (P=0.28). The average of MDA concentration showed a significant difference in the liver and spleen of irradiated rats at 6 Gy for 14 days compared to the control (0.044 nmol/mg vs 0.008 nmol/mg, P=0.03 and 0.032 nmol/mg vs 0.014 nmol/mg, P=0.05, respectively)., Conclusion: The administration of Curcuma xanthorriza Xorb extract was able to reduce MDA concentrations in the liver and spleen although not statistically significant. In addition, exposure to ionizing radiation at a dose of 6 Gy significantly increased lipid peroxidation in the liver and spleen by 5.5 times and 2.3 times, respectively.

Objective: The aim of this study was to assess the effect of radiation exposure, human 8-oxoguanine DNA N-glycosylase-1 (hOGG1) exon 7 genetic polymorphism and confounding factors on DNA damage response., Methods: Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) and alkaline Comet assay method were applied to determine the hOGG1 genetic polymorphisms and DNA damage response. A total of 80 participants were enrolled in this study, consisting of 40 radiation-exposed workers as a case group and 40 non-radiation workers as a control group., Result: The genotypes frequencies for controls were Ser/Ser (35%), Ser/Cys (32.5%), and Cys/Cys (32.5%), with frequencies of alleles being 326Ser (0.52) and 326Cys (0.48), whereas the genotypes frequencies for radiation-exposed workers (cases group) were Ser/Ser (17.5%), Ser/Cys (57.5%), and Cys/Cys (25%), with frequencies of alleles being 326Ser (0.46) and 326Cys (0.54). The results indicated that DNA damage response were not significantly higher in the exposed workers than in controls (22.55 ± 6.02 versus 21.72 ± 7.14; P=0.58). The time of exposure has a significantly negative correlation with comet tail length value among radiation workers. In addition, it was found that the DNA damage response was strongly associated with age and time of exposure with a decrease of 0.6 percent (P-value: 0.008) and 0.58 percent (P-value: 0.009), respectively. Whereas gender, smoking habit, and equivalent dose were not correlated with DNA damage., Conclusion: The single-nucleotide polymorphism of hOGG1 exon 7 (rs1052133) demonstrated no association with the extent of DNA damage in radiation-exposed workers.

High expression of phospho histone γ-H2AX, a sensitive marker of double stranded DNA damage, is believed to be an indication of defective DNA repair pathway or genomic instability that may cause mutations and ultimately cancer. DNA damage can be caused by ionizing radiation exposure. Beside in medical treatment/diagnosis or industry, ionizing radiation exposure can also be found in naturally in regions of high natural back ground radiation. In this study we collect the blood from 45 volunteers living in Mamuju, a region with highest natural radiation in Indonesia (dose of ∼7 mSv/year). Subjects were grouped as high natural background area (HNBA) (n = 37) and control area (n = 8). The expression γ-H2AX foci were evaluated by one of researcher fluorescence microscope examination. Our results show that the average foci numbers per cell were in the normal range. While not statistical different, the average of γ-H2AX foci in exposed area higher in the exposed compared to the control area, 0.31 versus 0.13 (p > 0.05), respectively. Moreover, there was also no statistical difference of average γ-H2AX foci between man and woman, old and young people in exposed and control area (p > 0.05). In this preliminary study we find 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 (albeit not significant) average values relative to the control area. More research is needed to further scrutinize these observations., (Copyright © 2017 Elsevier Ltd. All rights reserved.)