Hi Ray, You dont say what type of cells you are looking at. If they are large epithelial-like cells this could be a bit of non-specific cytplasmic uptake but that is unlikely to be confined to the G1 population. Or do you see a general width increase as well? Alternatively it could be FACSRubbish. Are you triggering on FSC or FL2? If you trigger on FSC and look at the AvW plot does that wide 'G1" population look as if it is heading off towards the origin? I have seen this sort of thing when there is a lot of debris or alternatively when the culture from which the cells are taken has been contaminated. In either case, it would probably be productive to have a look down the microscope and see if you can determine what could be causing it. Hope this helps etc Derek Ray Hetser wrote: > Several times over the last few months when analyzing cells that have > been stained with propidium iodide we have seen, using pulse processing, > cells that have an FL2W signal that would seem to qualify them as > doublets and yet their FL2A is similar to that of a singlet. E.g., in > the example below, if xxx represent G0/G1 single cells, yyy are G2/M > single cells, and zzz doublets, what are the cells represented by ???? ? ************************************************************************ Derek Davies Voice: (44) 0171 269 3394 FACS Laboratory, FAX: (44) 0171 269 3100 Imperial Cancer Research Fund, e_mail: derek.davies@icrf.icnet.uk London, UK Web Page: http://www.icnet.uk/axp/facs/davies/index.html In tenebris lux *************************************************************************
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