Wayne H waharri at
Thu Nov 12 15:55:14 EST 1998


I am a newbie to the world of flow but the question Artur Plett
addressed a question that i also had about viability staining. I
recently read a paper that talked about the problem with staining with
PI when fixing cells. Since PI stains reversibly, the leakiness that
results from fixing will allow the PI that may leak out of true "dead"
cells  and to leach into leaky "viable" cells after fixing. To
circumvent this, they recommended that ethidium monoazide be used. it
binds irreversibly and can be photochemically crosslinked to nucleic
acids using visible light. The fluor can be excited using a standard
laser at 488nm and can be distinguished from PE and FITC. I realize that
I am probably not doing the paper justice with my description
[Cytometry. 12(2):133-9, 1991]. I wanted to know what was the opinion
out there on this technique as an alternative to PI staining. And they
also stated that the EMA events can be resolved in a positive detection
channel. What does this mean?

Wayne A. C. Harris
Emory University, School of Medicine
Department of Gynecology and Obstetrics.
Gynecology Division Laboratory.
46 Armstrong St, Room 131
Atlanta, Ga.  30303
Phone: 404-616-4044
Fax: 404-525-6474

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