Abstract
Recent studies from our laboratory have shown that He ions induced chromatin breaks in unirradiated bystander cells. In this study, we examine the potential contribution of irradiated medium to the bystander effect. We can plate cells in either side or both sides of double mylar dishes. Since He ions can only traverse a very limited distance, cells plated on the other side of a medium-filled mylar dish (target cells) would have no chance of being hit by He ions. After one side (with or without cells) was irradiated by the He ions, the target cells were collected for cytogenetic assay using the PCC technique. Our results show that the number of aberrations in cell irradiated group is slightly higher than those in medium irradiated group. Furthermore, when transfer the medium of cell irradiated group, chromatin fragments were produced in the target cells added to the medium, while no damage was observed added to medium irradiated group. These results clearly show that some species induced chromosomal damage exists in medium of cell irradiated group. [J Radiat Res 44:417-418 (2003)]
