To the Editor.—In their article in the April 1988 issue of the Archives, Kozol et al1 cite an earlier study by me and my colleagues.2 Their discussion, however, misinterprets two points in our article and makes the differences in our findings appear greater than they are.
First, Kozol et al state that our study "was based on the trypan blue exclusion test for cell viability." In fact, we used cell survival in culture as our viability assay2,3 and found trypan blue staining to be a relatively insensitive indicator of cell damage, as Kozol et al found when they compared trypan blue staining with electron microscopy. The second error occurs when Kozol et al state that we "suggest that at lower concentrations (5×10−2%) of Dakin's solution, cultured fibroblasts are not killed." In our study, we found intact fibroblast viability at 0.5×10−2%, or 5×10−3%, a