Hello Paul, From your message I understand that you plan to do time series experiments with FITC labelled cells. I tried to study apoptosis with FITC labelled anexin and found out that after the first few images the cells were dying by necrosis. I found that exiting the fluorescent dye a few times is enough to kill the cells. You probably are very limited in the number of images you make. Greetings, Gert van Cappellen > I was wondering if anyone could suggest a method of counting cells in a > confocal field of view for use in an FITC-labelled-drug uptake study in > keratinocytes. I'm finding that I need a method of counting the total number > of cells, since some cells take up the drug very well and others don't at > all, so its hard to estimate the proportion of cells fluorescing etc. > > I'm now using a two channel system so dual labelling is a possibility (eg > with Texas Red conjugated to a live cell marker?), but I was hoping that > there was a simpler solution, particularly since these are time course > experiments over up to 24 hours. > > Thanks in advance! > > Paul > > Dr Paul White > Research Officer > Dermal Therapeutics R&D Programme > Royal Children's Hospital > Melbourne, Australia > > > Loretta Donders > Project Management Assistant > Dermal Therapeutics R&D Programme > The Royal Childrens Hospital > Flemington Road > Parkville Vic 3052 > AUSTRALIA > Phone: 61 3 9345 7909 > Fax: 61 3 9347 7763 > E-Mail: [log in to unmask] > ======================================================================== Gert van Cappellen, [log in to unmask] Erasmus University, Endocr.& Reprod., Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands Fax: +31 10 4366832