--- On Tue, 17 Aug 1999 14:41:29 -0400 James Liou <jliou@bu.edu> wrote: > To those with expertise and experience using PI to look at sub 2N DNA >content as a measurement of apoptosis, I have a fairly basic question that >I hope you can answer. Does this assay definitively distinguish between >apoptosis and necrosis? > > I guess these days suspicion arises in the field of cell death because >almost everything is decribed as apoptosis. I just don't know if the PI >hypodiploid assay gives one the same DNA fragmentation readout as say TUNEL >or a laddering assay. If the PI assay is specific for apoptosis, what >would a necrosis profile look like in comparison? > In our early application of this assay, we found that conditions which induced necrosis [as detected morphologically and electrophoretically] did not produce the characteristic subdiploid peak of apoptosis [Blood, 82: 3392-3400, 1993 and Clin Immunol Immunolptahol 71: 14=-18, 1994]. Of course, late stage apoptotic cells are probably indistinguishable form necrotc cells but these may not even be whole cells and are excluded from analysis by gating. My best advice is to match your flow data with morphological criteria which should be clearly observable for cells undergoing apoptotic cell death. This will provide verification for your system. For a comparison of PI and TUNEL see AIDS Res Hum Retro, 14: 1413-1422, 1998. Regards, Tom -------------------------------------------------------- Thomas W. Mc Closkey, Ph. D. Director, Flow Cytometry North Shore University Hospital Biomedical Research Center 350 Community Drive Manhasset, Long Island, New York 11030 ph: 516-562-4844 [office]; 516-562-1135/4641 [lab] fax: 516-562-2866 8/20/99 2:07:57 PM E-mail: thomasm@nshs.edu --------------------------------------------------------
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