Initial radiation DNA damage observed in prematurely condensed chromosomes of G2-phase human lymphocytes and analytical model of ion tracks

Abstract

In the present work, we have adopted the premature chromosome condensation (PCC) technique to study the initial DNA damage in order to distinguish between the biological and physical components of the dose-effect curves. We have studied G2-chromatid breaks in human lymphocytes, isochromatid-type breaks as well as chromatid exchanges at two different sampling times: directly after irradiation (t0) and 12 hours later (t12). The lymphocyte samples have been exposed to 150 MeV and spread out Bragg peak (SOBP) proton beams, 22 MeV/u 11 B ions and for comparison to 60 Co γ rays. Dose-response curves for both types of breaks have been determined. We have shown that t0 G2-chromatid breaks follow linearquadratic dependence for all studied cases and could be used for estimation of the effective ion track radius. A comparison to the expected physical track radii leads to the conclusion that the biological repair mechanism considerably prevails the physical effect of the overlapping ion tracks even at the time t0. The results have been also compared to the dose-effect curves previously obtained in our chromosome aberrations study.

Special issue: Dynamics of systems on the nanoscale (2018). Editorial

“…These software packages have been designed to become powerful and universal instruments of computational research in the field of MBN Science, which should play a role of a "virtual microscope" and a "camera" capable to explore, simulate, record and visualize both structure and dynamics of the MBN-world with an atomistic level of accuracy, in order to both reproduce its known features and predict the new ones. In this Topical Issue, many contributions [12][13][14][15][16][17][18][19][20][21][22][24][25][26][27][28][29][30][31][32][33][34][35] provide case studies conducted with these packages and demonstrate their application to a broad variety of topical areas in MBN science as listed at the beginning of this Editorial. To be noted that these universal and powerful software packages are fully applicable to a broad variety of the topical areas of the MBN Science listed above in the introductory part of the Editorial.…”

“…Study by Kowalska et al [27] discussed the premature chromosome condensation (PCC) technique to study the initial DNA damage in order to distinguish between the biological and physical components of dose-effect curves. Specifically, G2-chromatid breaks in human lymphocytes were investigated at two different sampling times: directly after irradiation and 12 hours later.…”