title: High throughput measurement of γH2AX DSB repair kinetics in a healthy human population.
abstract: The Columbia University RABiT (Rapid Automated Biodosimetry Tool) quantifies DNA damage using fingerstick volumes of blood. One RABiT protocol quantifies the total γ-H2AX fluorescence per nucleus, a measure of DNA double strand breaks (DSB) by an immunofluorescent assay at a single time point. Using the recently extended RABiT system, that assays the γ-H2AX repair kinetics at multiple time points, the present small scale study followed its kinetics post irradiation at 0.5 h, 2 h, 4 h, 7 h and 24 h in lymphocytes from 94 healthy adults. The lymphocytes were irradiated ex vivo with 4 Gy γ rays using an external Cs-137 source. The effect of age, gender, race, ethnicity, alcohol use on the endogenous and post irradiation total γ-H2AX protein yields at various time points were statistically analyzed. The endogenous γ-H2AX levels were influenced by age, race and alcohol use within Hispanics. In response to radiation, induction of γ-H2AX yields at 0.5 h and peak formation at 2 h were independent of age, gender, ethnicity except for race and alcohol use that delayed the peak to 4 h time point. Despite the shift in the peak observed, the γ-H2AX yields reached close to baseline at 24 h for all groups. Age and race affected the rate of progression of the DSB repair soon after the yields reached maximum. Finally we show a positive correlation between endogenous γ-H2AX levels with radiation induced γ-H2AX yields (RIY) (r=0.257, P=0.02) and a negative correlation with residuals (r=-0.521, P=<0.0001). A positive correlation was also observed between RIY and DNA repair rate (r=0.634, P<0.0001). Our findings suggest age, race, ethnicity and alcohol use influence DSB γ-H2AX repair kinetics as measured by RABiT immunofluorescent assay.
authors: Center for Radiological Research, Columbia University, New York, New York, United States of America.
authors: Preety M
authors: PM
authors: Sharma
authors: Center for Radiological Research, Columbia University, New York, New York, United States of America.
authors: Brian
authors: B
authors: Ponnaiya
authors: Center for Radiological Research, Columbia University, New York, New York, United States of America.
authors: Maria
authors: M
authors: Taveras
authors: Center for Radiological Research, Columbia University, New York, New York, United States of America.
authors: Igor
authors: I
authors: Shuryak
authors: Center for Radiological Research, Columbia University, New York, New York, United States of America.
authors: Helen
authors: H
authors: Turner
authors: Center for Radiological Research, Columbia University, New York, New York, United States of America.
authors: David J
authors: DJ
authors: Brenner
mesh_terms: D000328:Adult; D000367:Age Factors; D000428:Alcohol Drinking / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D005006:Ethnicity; D005260:Female; D006262:Health; D057166:High-Throughput Screening Assays / Q000379:methods*; D006657:Histones / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D044469:Racial Groups; D012727:Sex Characteristics; D055815:Young Adult
chemical_list: C468783:H2AX protein, human; D006657:Histones