Abstract
We have investigated bystander chromosomal damage in primary normal human bronchial epithelial (NHBE) cells irradiated with low-energy He-ion broad beams. Special 'strip' track segment dishes were made by cutting the Mylar surface on the bottom of special cell dishes into many equal strips and removing alternate strips. The remaining Mylar strips are sufficiently thick to stop the incident He ions, so that cells placed on these surfaces are never irradiated with He ions. When the unirradiated cells were kept with He-ion irradiated cells on the dishes, bystander chromosomal effect was observed in the unirradiated bystander cells. Many types of chromatid-type fragments, such as chromatid break, acentric fragment, isochromatid deletion and interchromatin exchange, were observed in the direct hit cells. On the other hand, only chromatid breaks and acentric fragments were observed in the bystander cells. There is evidence that simple chromosomal damage occur in bystander chromosomal effect.
