Cooperative inactivation of cells in microcolonies treated with UVA radiation.
Microcolonies of Madison-Darby canine kidney cells (MDCK II) were exposed to UVA radiation, and the number of cells with membrane damage was determined by staining with propidium iodide and fluorescence microscopy. The cells were clearly damaged in a nonrandom manner: The distribution of damaged cells per microcolony was incompatible with the assumption that the cells were damaged independently. The data were accurately described by a so-called propagated damage model in which a damaged cell can influence its neighbors in a propagating manner. These findings do not agree with the common view that optical radiation interacts with cells in a way in which damage manifested in a cell is the result of absorption of light in the same cell.
Department of Biophysics, Institute for Cancer Research, The Norwegian Radium Hospital, Ullernchausseen 70, Montebello 0310, Oslo, Norway.
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Bagdonas
J
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Dahle
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O
Kaalhus
J
J
Moan
D000818:Animals; D002450:Cell Communication / Q000528:radiation effects; D002460:Cell Line; D002470:Cell Survival / Q000528:radiation effects*; D004285:Dogs; D014466:Ultraviolet Rays