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The purpose of the present study is to evaluate the effect of curcumin as a natural compound against radiation induced γ-foci and stable chromosome aberrations. Whole blood samples form three human volunteers were pretreated with curcumin at different concentrations (0.5, 10, 20 and 100 μg/ml). After 1-hour incubation, the lymphocytes were exposed to γ-rays (0.05, 0.5, 1 and 2 Gy). Radiation induced changes in cells were quantified using γ-H2AX/53BP1 assay and FISH analysis. Our results have shown that curcumin significantly reduced the frequency of both γ-foci and translocations. We found concentration-dependent increase of curcumin protective effect on γ-H2AX/53BP1 foci formation at all radiation doses. Concerning the translocations, after 0.05 and 0.5 Gy γ-rays the values of genomic frequencies are comparable within each dose and we did not observe any impact of curcumin. The most protective effect after 1 Gy exposure was found at 100 μg/ml curcumin. At 2 Gy irradiation, the maximum protection was achieved at 0.5 and 10 μg/ml of curcumin. Concentrations of 20 and 100 μg/ml also prevent lymphocytes but to less extent. Our in vitro study indicates radioprotective efficacy of curcumin against γ-ray induced damages in human lymphocytes. This observation suggests that curcumin may play a role to protect patients undergoing radiological procedures.

The Running the European Network of biological and retrospective dosimetry (RENEB) network of laboratories has a range of biological and physical dosimetry assays that can be deployed in the event of a radiation incident to provide exposure assessment. To maintain operational capability and provide training, RENEB runs regular inter-laboratory comparison (ILC) exercises. The RENEB ILC2021 was carried out with all the biological and physical dosimetry assays employed in the network. The focus of this paper is to evaluate the results from 6 laboratories that took part using the gamma-H2AX radiation-induced foci assay. For two laboratories this was their first RENEB ILC. Blood samples were homogenously exposed to 240 kVp X rays (1 Gy/min) to provide calibration data, (0–4 Gy), and a few weeks later three blind coded test samples, (0, 1.2 and 3.5 Gy) were prepared. All samples were allowed a 2 h repair time at 37°C before being transported, on ice packs, to the participating laboratories. On arrival, the samples were processed, scored either manually or automatically for gamma-H2AX foci and dose estimates for the 3 blind coded samples sent to the organizing laboratory. The temperature of samples during transit and the time taken to report the dose estimates were recorded. Subsequent examination of the data from each laboratory used the doses estimates to assign triage categories to the samples. After receipt of the samples, the quickest report of dose estimates was 4.6 h. Analysis of variance revealed that the laboratory carrying out the assay had a significant effect on the foci yield (P < 0.001) for the calibration data, but not on the dose estimates of the blind coded samples (P = 0.101). All laboratories correctly identified the unirradiated and irradiated samples, although the dose estimates for the latter tended to under-estimate the dose. Two participants seriously under-estimated the dose for the highly exposed sample, which resulted in the sample being placed in the lowest triage category not the highest. However, this under-estimation resulted from the samples not remaining cold during shipment, due to a delay in transit and was not related to the experience of the participating laboratory. Overall, the RENEB network laboratories have demonstrated it is possible to quickly identify a recent whole-body acute exposure using the gamma-H2AX assay within the conditions of the ILC. In addition, an ILC provides a useful training and harmonization exercise for laboratories.

Curcumin is a component of natural spice Curcuma longa. It is known that this polyphenol has been shown to exhibit anti-inflammatory, anticancer, antiviral, antioxidant and antibacterial activities. The mechanism of curcumin effectiveness on both healthy and cancer tissues is still unclear. Aims: In vitro assessment of curcumin effect on both double-strand breaks and chromosomal translocations frequency, after γ-irradiation. Methods: Human peripheral blood samples were pre-treated with different concentrations of curcumin (0.5 µg/ml; 10 µg/ml; 20 µg/ml and 100 µg/ml). Thereafter they were exposed to 60Co γ-rays using various irradiation doses (0.05 Gy; 0.5 Gy; 1 Gy and 2 Gy). Both γ H2AX/53BP1 foci assay and FISH analysis were used to evaluate DNA double-strand breaks and translocation frequencies. Results: Curcumin pre-treatment exhibited significant lower γ-H2AX/53BP1 foci appearance and reduced translocations frequency in irradiated compared to untreated lymphocytes. At 1 Gy irradiation and 10 µg/ml curcumin, the reduction of total translocations frequency was 42%. We found that at 2 Gy irradiation, the most protective concentration was 0.5 µg/ml curcumin. In this case, translocations declined almost twofold compared to curcumin non-treated cells. Conclusion: The present in vitro study demonstrates that curcumin reduces both γ-H2AX/53BP1 foci and translocations occurrence in peripheral blood lymphocytes, after γ-irradiation.

The aim of this study was to evaluate the genotoxic effects of ionizing radiation in vivo in exposed Bulgarian nuclear power plant workers by using classical cytogenetic and molecular cytogenetic analyses of peripheral lymphocytes. Chromosome analysis using fluorescence in situ hybrydization (FISH) and Giemsa techniques was undertaken on 63 workers and 45 administrative staff controls from the Bulgarian Nuclear Power Plant. Using the Giemsa method, the frequencies of cells studied with chromosome aberrations, dicentrics plus rings and chromosome fragments in the radiation workers were significantly higher compared with the control group (P = 0.044, P = 0.014, and P = 0.033, respectively). A significant association between frequencies of dicentrics plus rings and accumulated doses was registered (P < 0.01). In the present study, a FISH cocktail of whole chromosome paints for chromosomes 1, 4 and 11 was used. A significant association between frequency of translocations and accumulated doses was also observed (P < 0.001). Within the control group, a correlation was found between age and the spontaneous frequency of translocations. No correlation was found between smoking status and frequency of translocations. When compared with the control group, workers with accumulated doses up to 100 mSv showed no increase in genome translocation frequency, whereas workers with accumulated doses from 101 to 200 mSv showed a statistically significant doubling of genome translocation frequency (P = 0.009). Thus, in cases of chronic exposure and for purposes of retrospective dosimetry, the genome frequency of translocations is a more useful marker for evaluation of genotoxic effects than dicentric frequency.

International audience; Purpose: RENEB, ‘Realising the European Network of Biodosimetry and Physical Retrospective Dosimetry,’ is a network for research and emergency response mutual assistance in biodosimetry within the EU. Within this extremely active network, a number of new dosimetry methods have recently been proposed or developed. There is a requirement to test and/or validate these candidate techniques and inter-comparison exercises are a well-established method for such validation. Materials and methods: The authors present details of inter-comparisons of four such new methods: dicentric chromosome analysis including telomere and centromere staining; the gene expression assay carried out in whole blood; Raman spectroscopy on blood lymphocytes, and detection of radiation-induced thermoluminescent signals in glass screens taken from mobile phones. Results: In general the results show good agreement between the laboratories and methods within the expected levels of uncertainty, and thus demonstrate that there is a lot of potential for each of the candidate techniques. Conclusions: Further work is required before the new methods can be included within the suite of reliable dosimetry methods for use by RENEB partners and others in routine and emergency response scenarios. © 2016 Crown Copyright. Published by Informa UK Limited, trading as Taylor & Francis Group.

Within the EU RENEB project, seven laboratories have taken part in training and harmonisation activities to strengthen triage gamma-H2AX-based radiation exposure assessment. This has culminated in a second triage biodosimetry exercise.Whole blood and separated lymphocyte samples were homogenously irradiated withAverage dose estimates across all the laboratories correlated well with true doses. The most accurate assignment of triage category was achieved by manual scoring of the 4-h blood and lymphocyte samples. Only three samples out of a total of 46 were miscategorized in a way that could have adversely effected the clinical management of a radiation casualty.This inter-comparison exercise has demonstrated that following a recent acute radiation exposure, the gamma-H2AX assay could be a useful triage tool that can be successfully applied across a network of laboratories.

Background: The purpose of the present study was to assess the cytogenetic effect of chronic low dose radiation exposure of nuclear power plant workers using the micronucleus centromere assay. This method allows the differentiation between centromere-positive micronuclei containing whole chromosome and centromere-negative micronuclei containing acentric fragment pointing to clastogenic action of ionizing radiation. Methods: The effect of low dose occupational exposure was estimated in 32 nuclear power plant workers using in situ hybridization (FISH) with the human pancentromeric DNA probe for peripheral blood lymphocytes. Group of 17 persons from administrative staff served as reference control group. Results: Data on the number of micronuclei, centromere-positive micronuclei and centromere-negative micronuclei per 1000 binucleated cells for the workers were significantly higher compared with the control group (p = 0.001, p=0.01 and p=0.002 respectively). No differences in the studied indicators between smokers and non-smokers are observed. No correlation was found between age and frequency of micronuclei, centromere-positive and centromere-negative micronuclei. Conclusions: The slight increase of the micronucleus frequency with the accumulated dose, observed in the group of workers, is mainly due to an enhanced number of centromere-negative micronuclei. Thus, the application of the MN-centromere assay is suitable as the frequency of MNCM−is more useful marker instead of the total number of MN. Keywords: occupational exposure; NPP workers; micronucleus-centromere assay

Background: A radiation accident occurred on 14 June 2011 in an industrial facility in Bulgaria whit Co source (137 TBq) used to sterilise equipment. Five people received doses exceed 1Gy and led to development of acute radiation syndrome. Biological dosimetry based on dicentric analysis was performed and the averaged acute whole-body doses estimated for the five patients were from 1.2 to 5.6 Gy. The purpose of this study was to evaluate in vivo induced chromosome aberrations four months after accident in the most severely exposed subject. Methods: Fluorescence plus Giemsa (FPG) staining and Fluorescent in situ hybridisation (FISH) were used to detect chromosomal aberrations in peripheral blood lymphocytes from the study subject four months after accidental exposure. FISH was provide using DNA probes specific for whole chromosomes #1, #4 and #11. Results: The mean frequency of dicentrics per cell ±SE was 0,425±0,042 determined by FPG. By FISH analysis the genomic frequency of apparently simple translocations (AST) per cell was 0,707±0,030. Incomplete translocations account for about 35%. For apparently simple dicentrics (ASD) the genomic frequency was calculated as 0,190±0,020. The frequency of complete plus incomplete dicentrics was 0,275 ± 0,020. Chromosome 1 was found to be involved in 52,35% of the total yield. Chromosome 4 was found to be involved in 30,2 % and chromosome 11 was involved in 22,82% of the total yield of translocations. Among 157 aberrant cells 28 cells or 17,83% were with one or more complex exchanges. Conclusions: This is a pilot study for a long time follow up assessing in vivo cytogenetic abnormalities in radiation accidentally exposed in Bulgaria persons. It is not possible at this to relate high frequency of translocation with long-term biological effect, but it is well known fact that ionizing radiation increase cancer risk in some individuals.

This paper details the construction of a 137 Cs gamma calibration curve that has been established for dicentric assay and the testing and validation of the curve through biological dosimetry in three situations of suspected workplace overexposure that arose accidentally or through negligence or lack of appropriate safety measures. The three situations were: (1) suspected 137 Cs contamination in a factory air supply; (2) suspected exposure to an industrial 192 Ir source; and (3) accidental exposure of construction workers to radiation from a 60 Co radiotherapy source in a hospital medical physics department. From a total of 24 potentially-exposed subjects, only one worker was found to have a statistically significant dose (0.16 Gy, 95% confidence intervals 0.02―0.43 Gy). In all other cases, the main function of the biological dosimetry was to reassure the subjects that any dose received was low.

In 2011, a serious radiation accident occurred in Stamboliyski, Bulgaria, in an industrial sterilisation facility using very-high-activity 60Co sources. For the five persons accidentally exposed, biological dosimetry based on dicentric analysis was performed in Sofia and in Paris, where the patients were transferred for treatment. Before completing the chromosomal dose assessment, and for the most exposed person, a preliminary cytogenetic evaluation based on electronically transmitted metaphase images was made. The averaged acute whole-body dose estimates for the five patients ranged from 5.2 to 1.2 Gy, and good agreement was obtained between the two laboratories. The patients were also assessed by their prodromal responses and depressed blood cell counts over the first week. The cytogenetic dose estimates were in good accord with those derived from the blood counts, and both techniques indicated that, for the two most seriously exposed persons both techniques indicated that the initial prodromal reactions had suggested somewhat less severe exposure. Language: en