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@#Background. Accidental radiation exposure can occur anytime. Biodosimeters help in quantifying the absorbed dose of individuals who are not equipped with personal dosimeters during radiation exposure. The dicentric assay can quantify radiation damage by correlating radiation dose exposure with the frequency of dicentric chromosomes in the peripheral lymphocytes extracted from exposed individuals. Objective. The study aims to present the interim results of the reference dose-response curve for a Philippine radiotherapy facility constructed using a 6MV linear accelerator (ClinacX, Varian). Methods. Samples of peripheral blood from healthy volunteers were irradiated in a customized water phantom of doses 0.10 to 5.0 Gray using a linear accelerator. The irradiated samples were cultured and analyzed following the International Atomic Energy Agency Cytogenetic Dosimetry Protocol (2011) with modifications. Linear-quadratic model curve fitting and further statistical analysis were done using CABAS (Chromosome Aberration Calculation Software Version 2.0) and Dose Estimate (Version 5.2). Interim results of the samples were used to generate these curves. Results. The dose-response curve generated from the preliminary results were comparable to published dose response curves from international cytogenetic laboratories. Conclusion. The generated dose-response calibration curve will be useful for medical triage of the public and radiologic staff accidentally exposed to radiation during medical procedures or in the event of nuclear accidents.
Subject(s)
Cytogenetics , Biological Assay , Chromosome Disorders , Cytogenetic Analysis , RadiationABSTRACT
Radiation biodosimetry is an important part of radiation medicine. Some new discoveries and progresses have been made in radiation biodosimetry studies in recent years. Cytogenetic method represented by chromosome aberration analysis as the golden standard of radiation biodosimeter is being transformed to automate analysis, and a number of international, regional and national laboratory networks of radiation biodosimetry are being established. As a widely acceptable molecular marker of DNA damage,γ-H2AX has made rapid progress in radiation dose estimation. Based on the expressions of protein and genes, further advancements have been made in the studies of metabolites and miRNAs. At the same time, with the development of proteomics technology, there are some breakthroughs in the study of using molecular expression profiling to evaluate radiation dose. The research progresses of radiation biodosimetry is reviewed in this paper.
ABSTRACT
Radiation biodosimetry is an important part of radiation medicine. Some new discoveries and progresses have been made in radiation biodosimetry studies in recent years. Cytogenetic method represented by chromosome aberration analysis as the golden standard of radiation biodosimeter is being transformed to automate analysis, and a number of international, regional and national laboratory networks of radiation biodosimetry are being established. As a widely acceptable molecular marker of DNA damage,γ-H2AX has made rapid progress in radiation dose estimation. Based on the expressions of protein and genes, further advancements have been made in the studies of metabolites and miRNAs. At the same time, with the development of proteomics technology, there are some breakthroughs in the study of using molecular expression profiling to evaluate radiation dose. The research progresses of radiation biodosimetry is reviewed in this paper.
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Objective To detect the changes of the percentage of micronucleated reticulocytes (MN-RET) in the peripheral blood of mice exposed to 60Co γ-rays,in order to provide evidence for a new biomarker of radiation biodosimetry.Methods ICR mice were irradiated in whole body with 0,0.5,1,2,4 and 8 Gy at a dose rate of 0.24 Gy/min.Peripheral blood was collected for MN-RET assay using a flow cytometry.Results The percentage of peripheral MN-RET increased steadily with irradiation doses up to 2 Gy and then had a downtrend beyond 2 Gy.The changes of MN-RET observed with a microscope were consistent with the results from flow cytometry.The dose response of the MN-RET fitted to a lineal model (R2 =0.9063),and the MN-RET at 2 Gy was significantly higher than that of nonirradiated control (t =-2.856,P ＜ 0.05).Conclusion Percentage of peripheral M N-RET could be an early,rapid and high-throughput radiation bio-dosimeter in certain range of doses.
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objective To study the changes of reticulocyte micronueleus(MN-RET)from peripherai blood and polychromatic erythrocyte mieronucleUS(MN-PCE)from bone marrow in mice following exposure to X-rays in order to provide an experimental basis for exploring possible hish-throughput radiation biodosimeter.Methods Male ICR mice were whole-body irradiated with 0,0.5,1,2,4 and 5 Gy at a dose rate of 0.488 Gy/min.MN-RET from peripheral blood wag scored with FCM and MN-PCE from bone marrow was scored with manual microscopy at 24,48 and 72 h post-irradiation.Results Both MN-RET and MN-PCE rates increaged with doses in the range of 0-5 Gy at 24,48 and 72 h after WBI.The dose-response relationship can be fit with linear equations(t=10.26-25.77,P<0.05).The correlation coeffcients between MN-RET from peripheral blood and MN-PCE from bone mallow were highly significant(r=0.986-0.996,P<0.05).Conclusions In view of its simplicity,accuracy and high throughput capacity,FCM scoring of peripheral blood MN-RET may be a candidate for radiation biodosimetry,More work should be carried out on human specimens to investigate this possibility.
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Objective To investigate the dose-response pattern on the inducible expression of PIG3 mRNA in normal human lymphoblastoid AHHI cells by 60Co γ-rays,and its possibility for developing novel radiation biodosimeter.Methods Laser confocal fluorescent microscopy was used to detect the γ-H2AX foci,a biomarker of DNA double-strand break.After irradiation with 0,1,2,4,6,8 and 10 Gy of 60Coγ- rays,AHH-1 cells were harvested at 4,10 and 24 h post-irradiation,and subjected to total RNA extraction and detection of PIG3 mRNA expression by quantitative real-time PCR.Results PIG3 protein foci were formed in the nuclei at 30 min after irradiation,and a part of these PIG3 foci were colocalized with γH2AX foci.After irradiation,PIG3 mRNA level was enhanced with the increased time of postirradiation,and remained an increased level at least till 24 h.The radiation-inducible expression of PIG3 mRNA was demonstrated in a dose-dependent manner.The dose-dependent range at 4 h post-irradiation was 0 - 6 Gy,and at 10 h and 24 h was 0 - 10 Gy.Conclusions PIG3 involves in the cellular response to DNA double-strand break.The dose-dependent inducible response of PIG3 mRNA expression might provide a valuable candidate for developing a novel radiation biodosimeter.
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Objective To detect the frequency of micronucleated polychromatic erythrocytes(fMNPCE) in mice bone marrow after irradiated with X-ray by flow cytometer(FCM) to study whether fMNPCE detecting method could become a rapid biodosimeter for early radiation damage. Methods BALB/c mice were randomly assigned to receive the X-ray irradiation at dose of 0.5,3.0,6.0 Gy(n=4 for each irradiation dose),and the bone marrow was collected in 6,12,24 h after irradiation.Another 4 mice were intraperitoneally injected with cyclophosphamide twice as positive control,of which the bone marrow was collected in 42 h after intoxication began and 4 treated with spurious radiation as normal control.Results fMNPCE in mice bone marrow increased remarkably in 24 h after exposure to 0.5 Gy X-ray(P