This Article Abstract Full Text Full Text (PDF) Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by van den Aardweg, G J M J Articles by Mooi, W J Search for Related Content PubMed PubMed Citation Articles by van den Aardweg, G J M J Articles by Mooi, W J

Changes in epidermal radiosensitivity with time associated with increased colony numbers

¹ Department of Radiation Oncology, Subdivision of Clinical Radiobiology, University Hospital Rotterdam—Daniel den Hoed Cancer Center/Dijkzigt Hospital, Josephine Nefkens Institute, PO Box 1738, 3000 DR Rotterdam, The Netherlands ² Normal Tissue Radiobiology Research Group, Research Institute (University of Oxford), Churchill Hospital, Oxford OX3 7LJ, UK ³ Department of Pathology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands

View larger version (116K): [in a new window]   Figure 1. (A) Histological cross-section of pig epidermis after enzymatic separation with dispase. Notice that all epidermal cell layers are present and that the undulations of the basal membrane are intact. H&E staining, magnification x 100. (B,C) Bromodeoxyuridine (BrdU)-positive cells in the dorsal area of unirradiated pig epidermis, either as a solitary cell (B) or as pairs (C). Magnification x 1000. (D,E) Colonies containing >16 tightly packed, BrdU-positive cells at 14 days (D) and 25 days (E) after a single dose of 27 Gy. Magnification x 200.

View larger version (22K): [in a new window]   Figure 2. Changes in number of bromodeoxyuridine (BrdU)-positive cells in the unirradiated skin of young pigs, 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, 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.

View larger version (19K): [in a new window]   Figure 3. Changes in number of bromodeoxyuridine (BrdU)-positive cells (,) and the percentage of paired cells (,) in unirradiated pig epidermis with increasing time after BrdU labelling. The results for two young pigs, pig E (open symbols) and pig F (solid symbols) are presented.

View larger version (20K): [in a new window]   Figure 4. Cell survival curves for colonies in pig epidermis containing 16 bromodeoxyuridine-positive cells at different times after various levels of irradiation. ____, Frequent biopsying of different skin fields in the same animals over a short period of time after irradiation; ----, biopsying of all skin fields simultaneously after irradiation. Three different levels, ED20, ED50 and ED80, for the incidence of moist desquamation as obtained from an in vivo study are indicated for comparison.

View larger version (23K): [in a new window]   Figure 5. Cell survival curves for colonies in pig epidermis containing different numbers of bromodeoxyuridine (BrdU)-positive cells. The four categories of colony size are indicated by the number of BrdU-positive cells per colony. Skin biopsies were taken at (a) 14/15 days, (b) 17/18 days, (c) 21/22 days and (d) 25/26 days after irradiation. Data for 27 Gy at 25/26 days after irradiation (d) were not included in the analysis. Data obtained by Chen et al [1], using a comparable clonogenic assay, are indicated in (c) for comparison (---).