7-AAD
Brent Dorsett (brentd@nyct.net)
Fri, 31 Jan 1997 15:30:37 -0500 (EST)
Please excuse me for being a little behind the flow but I've had the
midwinter sniffles. I was just catching up on the recent live cell
discrimination dialog. In one of the replies was a reference to a monograph
from the University of Washington about using 7-AAD. Included in it were
instructions for making a solution in DMSO, since it is not water soluble
and storing 1 month at 4 degrees C because of limited stability. This I
confirmed with a call to Calbiochem. All this came as something of a
surprise to me since I have been using ( perfectly successfully ) an aqueous
solution of 7-AAD since I read Ingrid Schmid's Cytometry article in 1992.
In fact the last batch ( 50 ml made in PBS with azide @ 25 ug/ml and used at
1 ug/ml ) was made in 1995 -- stored at 4=BAC in the dark has no precipitate
and works just fine. Whenever some project calls for dead cell
discrimination in three color flow -- out comes the 7 AAD. Now don't get me
wrong -- I'm not suggesting that I'm right and others are wrong. I'm just
reporting the facts I've observed. Since that batch was made there have
never been any observable shifts in fluorescence intensity or required
compensation. Maybe ignorance has just been bliss. At any rate I would be
interested in whether anyone else has used 7AAD from aqueous stock=
solutions.
Brent Dorsett
chief, flow cytometry facility
Lenox Hill Hospital, NYC =20
CD-ROM Vol 3 was produced by Monica M. Shively and other staff at the
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If you have any comments please direct them to
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PUCL, Purdue University, West Lafayette, IN 47907.
Phone: (765)-494-0757;
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