**4. Conclusion**

452 Selected Topics in DNA Repair

showing false results, that is lower damage. Cebulska et al. (2007) showed negative influence of smoking on the efficiency of DNA repair in lymphocytes. On the other hand, Rzeszowska-Wolny et al. (2005) did not find significant correlation between smoking and DNA damage and DNA repair after the irradiation of human lymphocytes with the dose of 2 Gy. Our results also did not show the influence of smoking on DNA repair of primary damage, except for the tail length after the exposure to 4 Gy dose. The results are similar to

It is still not clear whether the basal damage differ due to gender. Dusinska et al. (2004a) did not find the difference in creation of strand breaks, nor in the amount of DNA damage sensitive to action of specific enzymes such as endonuclease III, or FPG enzyme or alkali labile sites, although male had lower DNA damage after the treatment with hydrogen peroxide (Dusinska et al., 2004a, b). Bajpayee et al. (2002) showed that healthy men have more basal damage in lymphocytes than women. Our results showed that difference was only seen after the 4 Gy dose, where women had higher values for DNA damage in all three parameters observed in comet assay immediately after and 24 hours after the irradiation. There was not similar number of male and female, and that could also influence the results. Trzeciak et al. (2008) showed that there are differences in the amount of damage and the repair rate after the exposure of whole blood sample to 6.3 Gy dose. But most of the experiments did not show the gender influence on DNA repair capacity (Muller et al., 2001,

Age influence was not seen in this experiment. That is in agreement with other authors (Betti et al., 1994; Frenzili et al., 1997). Rzeszowska-Wolny et al. (2005) did not show the influence of sex on DNA damage level and DNA repair by the comet assay after the exposure to 2 Gy dose. Maluf et al. (2001) showed positive correlation of age and DNA repair in the exposed group. Singh et al. (1988) described positive correlation between the

Although former results showed the existence of radio adaptive response, our results did not confirm the relationship between primary DNA damage and adaptive response. Few authors have also shown lower DNA damage levels after the repeated exposure to ionising radiation (Sankaranarayanan et al., 1989; Wang et al., 1991; Ikushima, 1992; Domingues et

APE1 gene is involved in BER repair. Polymorphism in exon 5 is connected with hypersensitivity during the exposure to ionising radiation (Au et al., 2006). Results are in agreement with Au et al. (2006). There was positive correlation of polymorphic variants and

Polymorphic variants of hOGG1 gene showed positive correlation with TI and TM measured immediately after the exposure to the dose of 2 Gy. The results are in agreement with Aka et al. (2004) who showed the connection between polymorphic variants of hOGG1 Ser326Cys with lower capability of repair of oxidative DNA damage in the exposed, but not in the control group measured 60 and 120 minutes after the exposure to 2 Gy. After 120 minutes from the exposure, 71 % of individuals with high level of DNA damage had polymorphic variant of hOGG1 gene. Cornetta et al. (2006) did not show the influence of

Goode et al. (2002)) showed the connection between polymorphic variants of hOGG1 with higher risk of lung, head and neck cancer. hOGG1 and XRCC1 are involved in the same

Aka et al. (2004) on nuclear power plant workers.

2002; Rajaee-Behbahani et al., 2001; Marcon et al., 2003).

DNA damage level 120 minutes after the exposure to 2 Gy.

age and DNA damage in non-smokers.

hOGG1 polymorphism on DNA damage.

al., 1993).

The results indicate that in addition to individual gene polymorphisms, the influence of combinations of polymorphic genes to DNA damage and repair should be tested.
