Abstract

Background

Biodosimetry with persistent cytogenetic indicators in peripheral blood lymphocytes (PBLs) plays crucial role in regulatory/medical management of individuals overexposed to radiation. Conventional methods require ∼48 h culture and have limited dose range (0.1–5Gy) applications due to checkpoint arrest/poor stimulation. G0-Phase Premature chromosome condensation (G0-PCC) allows chromosome aberration analysis within hours after blood collection. Due to high skill demand, applications of G0-PCC were not very well explored and being re-visited worldwide. Among all aberrations, analysis of excess chromosomal fragments is quickest. Radiation dose response curve for the fragments has been reported.

Purpose

In present study, excess fragment analysis has been addressed in detail, in addition to validation of radiation dose response curve, gender variation in the response, dose dependent repair kinetics, minimum detection limit (MDL), duration and accuracy of final dose estimation with 5blindfolded, ex vivo irradiated samples have been studied. In extension, feasibility of multiparametric dosimetry with Fluorescent in situ hybridization (FISH) based endpoints were qualitatively explored.

Material and methods

PBLs were exposed to Gamma-Radiation and G0-PCC was performed at different time points. Decay kinetics and dose response curve were established. Gender Variation of the frequency of the fragments was assessed at 0, 2 and 4 Gy. FISH was performed with G0-PCC applying centromere probe, whole chromosome paints, multi-color FISH and multi-color banding probes.

Results

Radiation response curve for fragments was found to be linear (Slope 1.09 ± 0.031 Gy-1). Background frequency as well as dose response did not show significant gender bias. Based on variation in background frequency of fragments MDL was calculated to be ∼0.3 Gy. Kinetics of fragment tested at 0, 4, 8, 16 and 24 h showed exponential decay pattern from 0 to 8 h and without further decay. Final dose estimation of five samples was completed within 13 man-hours. Dicentric chromosomes, translocations, insertions and breaks were identifiable in combination with centromere FISH and WCP. Advanced methods employing multicolor FISH and multi-color banding were also demonstrated with PCC spreads.

Conclusion

G0-PCC, can be useful tool for high dose biodosimetry with quick assessment of fragment frequency. Further, it holds potential for multi-parametric dosimetry in combination with FISH.

中文翻译：

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早染色体浓缩在辐射生物剂量测定中的多方面应用。

摘要

背景

在外周血淋巴细胞（PBL）中具有持续细胞遗传学指示剂的生物剂量测定法在过度暴露于辐射的个体的调节/医学管理中起着至关重要的作用。常规方法需要约48 h培养，并且由于检查点停滞/刺激性差而限制了剂量范围（0.1-5Gy）。G0-Phase早熟染色体凝集（G0-PCC）可在采血后数小时内进行染色体畸变分析。由于对技术的高要求，对G0-PCC的应用还没有进行很好的探索，并且正在全球范围内重新访问。在所有像差中，对多余染色体片段的分析最快。片段的辐射剂量反应曲线已有报道。

目的

在本研究中，除了验证辐射剂量反应曲线，反应中的性别差异，剂量依赖性修复动力学，最小检测限（MDL），5倍盲折叠的最终剂量估计的持续时间和准确性外，还详细解决了过量片段分析的问题。 ，已经研究了离体辐射样品。扩展地，定性地研究了基于荧光原位杂交（FISH）的终点的多参数剂量测定的可行性。

材料与方法

将PBL暴露于伽马射线辐射，并在不同的时间点进行G0-PCC。建立了衰变动力学和剂量反应曲线。片段频率的性别差异评估为0、2和4 Gy。用G0-PCC应用着丝粒探针，全染色体涂料，多色FISH和多色条带探针进行FISH。

结果

发现碎片的辐射响应曲线是线性的（斜率1.09±0.031 Gy-1）。背景频率以及剂量反应均未显示明显的性别偏见。根据片段背景频率的变化，MDL计算为约0.3 Gy。在0、4、8、16和24小时测试的碎片动力学显示出从0到8小时的指数衰减模式，并且没有进一步衰减。在13个工时内完成了五个样品的最终剂量估算。结合着丝粒FISH和WCP可以鉴定出双中心染色体，易位，插入和断裂。PCC涂抹酱还展示了采用多色FISH和多色条带的先进方法。

结论

G0-PCC可用于快速评估片段频率的高剂量生物剂量测定的有用工具。此外，与FISH结合使用，它具有进行多参数剂量测定的潜力。