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Sapra, B. K.

Publications and source records attributed to Sapra, B. K..

2 recordsLinked to original sources
bioRxiv2026

Decoding Chromosome Radiosensitivity in G0-Phase PBMCs: Genomic Determinants, Age, Sex effects, and Implications in Radiation Dose Assessment

Low-dose ionizing radiation from natural and anthropogenic sources is typically not of significant concern under normal conditions. However, in case of radiological incidents, it becomes an important environmental hazard, raising concern for public health and necessitating reliable biological indicators of exposure. Chromosomal aberrations are most reliable markers of radiation exposure and are more or less universally assessed in metaphases. Recently, rapid assessment of aberrations in G-phase lymphocytes using G-PCC-FISH has gained attention and is recognized as the most suitable method for dose assessment in cases of high-dose or partial-body exposure. This is first study in G-phase at such scale to establish baseline and radiation induced aberrations in peripheral blood mononuclear cells (PBMCs) from 24 healthy human donors (12 males, 12 females, 21-60 Y). Using whole chromosome painting (WCP) of Chromosomes 1, 2 & 4 and scoring across >8500 cells post 0, 2, and 4 Gy {gamma}-radiation exposure, we quantified 5586 aberrations and investigated their relationship with underlying genomic features. Our findings includeNo significant effect of age or sex on chromosomal radiosensitivity, supporting the robustness of pooled biodosimetric calibration curves for dose assessment within the studied age range of 21-60 years. Chromosome-specific radiosensitivity does not appear to be solely dependent on chromosome size and shows a potential association with gene density and total transcript length. From public health point of view the present data provides reference values for interphase chromosomal damage as well as radiation induced reference values for two important dose points across age groups and sexes. This approach enhances emergency preparedness for radiological events by enabling rapid biodosimetry, especially critical when metaphase cells are unavailable as in cases of accidental high-dose or partial exposures. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=110 SRC="FIGDIR/small/728688v1_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@4f8a68org.highwire.dtl.DTLVardef@7ed80org.highwire.dtl.DTLVardef@7977bforg.highwire.dtl.DTLVardef@a4c0be_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical Abstract:C_FLOATNO A 24-donor study to assess baseline and radiation response age and sex. Additionally substantial data analysed to assess radiosensitivity of chromosomes and its genomic determinants. C_FIG

genomics↗
bioRxiv2026

Does Low Dose Radiation Induced Adaptive Response Influence Initial DNA-DSB formation? Evidence from γH2AX foci Analysis in Human Lymphocytes

PurposeLow-dose radiation-induced adaptive response (LDRIAR) is well documented, but its role in early DNA damage signalling remains unclear. This study aimed to investigate whether adaptive response influences initial DNA double-strand break (DSB) recognition, as reflected by {gamma}H2AX foci formation, and to evaluate its time-dependent expression in human lymphocytes. Materials and MethodsPeripheral blood lymphocytes from three healthy donors were exposed to a priming dose followed by a challenging dose at defined time intervals. DNA damage was assessed using {gamma}H2AX foci analysis, comparing acute and split-dose exposures in both PHA-stimulated (large) and non-stimulated (small) lymphocytes. ResultsA clear time-dependent adaptive response was observed. No significant reduction in {gamma}H2AX foci was detected at 1 h (p > 0.05). At 2 h, a significant decrease was observed ([~]7-8% in large and [~]13% in small lymphocytes; p < 0.01), which increased at 4 h ([~]12% and [~]22%, respectively; p < 0.001). The maximal response occurred at 15 h, with reductions of [~]40- 43% in large and [~]27% in small lymphocytes (p < 0.001). Small lymphocytes exhibited an earlier response, while large lymphocytes showed a greater magnitude at later time points. The temporal trend was consistent across donors, with minor variability at later intervals. ConclusionsThe findings demonstrate that LDRIAR is reflected at the level of DNA damage signalling and follows a defined temporal pattern with cell-type specificity. This suggests that adaptive response may influence early DSB-associated processes, contributing to a better understanding of radiation response mechanisms in radiobiology.

molecular biology↗