Figure 2. Changes in number of bromodeoxyuridine (BrdU)-positive cells in the unirradiated skin of young pigs, {approx}3 months of age, prior to and after irradiation. For pigs A and B, the irradiated skin fields were biopsied over a period of 10–26 days after irradiation. For pigs C and D, all irradiated skin fields were biopsied at the same time at 24/25 days after irradiation. The mean number of BrdU-labelled cells in 11 control animals, {approx}7 months of age, is indicated for comparison. (See discussion for explanation of the significantly higher number of BrdU-positive cells 4 days prior to irradiation in pig B.) Arrows between days 0–5 indicate irradiation sessions.