Re: PharRed

From: Andy Riddell (ar3@mrc-lmb.cam.ac.uk)
Date: Sun Oct 03 1999 - 08:57:55 EST


>Andy,
>
>I've used Cy7APC for nearly 7 years now, and have never seen it fall
>apart as you describe.  Actually, what you describe sounds most like
>someone put propidium iodide in the sample--is that a possibility?
>
>You should be able to tell if it is APC-only signal by looking at the
>contribution of the "APC only" cells in the Cy7APC channel--and
>compare it to a truly APC-stained sample.  Only if the spillover into
>the Cy7APC channel is exactly the same for a true APC dye should we
>consider the possibility that the Cy7APC is falling apart.
>
>If it is falling apart, then you might want to check your
>solutions--maybe you have something in them that causes it to break
>down (however, we have used many types of fixatives without problems).
>
>Can you EMail me some of your datafiles?  Send me a collection that
>has unstained cells, APC-only, and Cy7APC-only stained cells (i.e.,
>your comp samples)--before & after compensation, if possible!
>
>mr

Mario,

Thanks for your input here. I think PI is unlikely in that as far as I'm
aware PI is poorly exited by a HeNe (at least in all my data charts for
it). However I have seen a similar result for the Red670 dyes. I don't have
the data files.

I did see the exact same intensity at the same position on a plot for
PharRed in the APC channel as the APC dye alone. So I concluded that the
batches we were using were breaking down. I haven't used PharRed since, but
am willing to it try again. It maybe that I have been unlucky in the
batches that I have used. NB I have only used 2 different batches and make
no claim about the integrity of the dye as a whole. I would like to
investigate this problem further and thank everyone for their input. I have
not heard of anyone else having this problem so it maybe that we are doing
something (as Mario suggested), so I would like to investigate this
further. If anyone else has any advice please let me know.


Thanks

Andy.

Andy Riddell
PNAC Division
MRC LMB
Hills Road
Cambridge
UK
tel: (0)1223 402218
fax: (0)1223 412178
email ar3@mrc-lmb.cam.ac.uk



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