Radiosensitivity in XXXX assessed by the Comet and @entity4523 assays.

@entity1 @entity0 @entity5 @entity4523 @entity74
Spontaneous and radiation-induced @entity74 of peripheral blood mononuclear cells derived from unselected @entity0 ( @entity0 ) @entity1 (n=50) was examined using the single-cell gel electrophoresis (Comet) assay and a modified G2 @entity4523 ( @entity4523 ) test. Cells from apparently healthy donors (n=16) and from @entity5 @entity1 (n=9) with an adverse early skin reaction to radiotherapy (RT) served as references. Nonirradiated cells from the three tested groups exhibited similar baseline levels of DNA fragmentation assessed by the Comet assay. Likewise, the Comet analysis of in vitro irradiated (5 Gy) cells did not reveal any significant differences among the three groups with respect to the initial and residual DNA fragmentation, as well as the DNA repair kinetics. The G2 @entity4523 test showed that cells from @entity5 @entity1 with an adverse skin reaction to RT displayed increased frequencies of both spontaneous and radiation-induced @entity4523 compared to healthy control or the group of unselected @entity0 @entity1 . Two @entity1 from the latter group developed an increased early skin reaction to RT, which was associated with an increased initial DNA fragmentation in vitro only in one of them. Cells from the other @entity0 @entity1 exhibited a striking slope in the dose-response curve detected by the G2 @entity4523 test. We also found that previous RT strongly increased both spontaneous and in vitro radiation-induced @entity4523 levels, and to a lesser extent, the radiation-induced DNA damage assessed by the Comet assay. These data suggest that clinical radiation may provoke @entity74 and/or induce persistent DNA damage in normal cells of @entity5 @entity1 , thus leading to increased levels of @entity4523 induction and DNA fragmentation after irradiation in vitro. Therefore, care has to be taken when blood samples collected postradiotherapeutically are used to assess the radiosensitivity of @entity5 @entity1 .
