The Repair of Dna Strand Breaks in Human Lymphocytes Exposed to Near Uv‐radiation (Uva) and Far Uv‐radiation (Uvc)

UVA irradiation of human lymphocytes induces DNA strand breaks and a portion of these breaks are closed at a slower rate than X‐ray induced DNA strand breaks and the strand breaks generated during repair of UVC induced DNA lesions. In addition, the yield of DNA strand breaks in lymphocytes pretreated with UVA radiation and given a subsequent exposure with UVC radiation is higher and shows a slower decrease with increasing repair time in comparison with the expected yield based on additivity between UVA and UVC induced DNA strand breaks. This indicates that UVA delays the closure of the intermediate strand breaks formed in the repair process of UVC induced DNA lesions.