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Watanabe, Ritsuko; Rahmanian, S.*; Nikjoo, H.*
Radiation Research, 183(5), p.525 - 540, 2015/05
Times Cited Count：68 Percentile：95.1(Biology)To calculate the spectrum of initial base damage induced by selected electrons and ions, Monte Carlo track structure method was used to simulate the radiation induced DNA damage in a cell mimetic condition based on a single track action. We present relative yield of strand breaks and base damage for selected monoenergetic electrons 100 eV - 100 keV, photons C
, Al and Ti; and some selected ions (3.2 MeV/u proton; 0.74 and 2.4 MeV/u 
He; 29 MeV/u 
N, and 950 MeV/u 
Fe). Data are presented for simple and complex types of DNA damage. The ratios of yields of base damage to SSBs were estimated to be about 2-4 independent on the LETs examined. The contribution of base damage to the complexity of damage site was shown to be significant. The data can be used for testing mechanistic models of DNA repair kinetics and in particular the base excision repair.
Yokoya, Akinari; Shikazono, Naoya; Urushibara, Ayumi; Fujii, Kentaro; Akamatsu, Ken; Watanabe, Ritsuko
Hoshasen Seibutsu Kenkyu, 40(2), p.168 - 184, 2005/06
Ionizing radiation causes modifications in a DNA molecule depending on the characteristic tack-structure in which two or more isolated lesions arise in a few nm scale (1 or 2 helical turn of DNA), known as "clustered DNA damage". These clustered DNA damages could be distinct from those by reactive oxygen species (ROS) endogenously induced on their severity of induction of biological effects such as mutation. However, the studies on the nature and repair mechanism of clustered DNA damage have still been behind because of the technical difficulties on determination of the chemical structure and yield. This article reviews some experimental evidences of the clustered DNA damages in this research field, as well as our recent progress on the studies on the clustered DNA damages using both molecular biological techniques and synchrotron spectroscopic method.
