@misc{Ugenskiene_Rasa_The_2007, author={Ugenskiene, Rasa}, address={Kraków}, howpublished={online}, year={2007}, school={Wydział Lekarski}, language={pol}, abstract={The exposure to ionizing radiation is known to cause a wide range of DNA damage. We aimed to analyze and to quantify the effect of different radiation qualities on double-strand break (DSB) and micronuclei (MN) formation in terms of dose and time. Norma! human skin fibroblast (AGO1522) cell line was used for the experiments. Cells were irradiated with 240 kV broad-field X-rays or targeted with different number of helium (3He) particles or protons (1H). It was determined that dose response via DSB induction was statistically significant and it was close to linear in the samples exposed to X-rays, 3He particles, and protons. 1 Gy of X-rays yielded ≈33 DSBs/cell. In microbeam experiments, the ratio of the number of delivered particles and yielded tracks equalled 1:1 and 3:1 following 3He and 1H irradiation, respectively. The DSB repair kinetics was radiation dose-independent. The fraction of the residual ATM and 53BP1-positive DSB foci decreased in a similar fashion in the samples exposed to either 0.1 or 0.25 Gy of X-rays. With respect to the effect of radiation quality, DSB repair was found to be radiation quality-dependent. DSBs induced by 3He particles were repaired significantly slower than those of proton irradiation. The quickest DSB repair was registered in the samples exposed to X-rays. ATM and 53BPI markers fully co-localized only in 66-86% of foci. As far as the DSB rep}, abstract={air kinetics is concerned, the fraction of ATM and 53BP1-positive foci decreased in a similar fashion in the samples exposed to X-rays. The dose response via MN formation was statistically significant and it was close to linear following X-ray irradiation. 1 Gy of X-rays yielded ≈8% of micronucleated cells. On the contrary, there was no significant time effect on MN formation kinetics observed. The MN yield of 0.09 per each 3He particle was determined. Following proton irradiation, the yield of micronuclei and the fraction of damaged cell showed a scattered type of response, which was in a range of 2-7%. MN size was similar irrespective of dose and radiation quality. The distribution of MN size suggested that two populations of MN were present.}, title={The effect of low dose ionizing radiation on normal human fibroblasts}, type={Praca doktorska}, keywords={X-rays, 3He particles, protons, double-strand breaks, micronuclei}, }