Peggy,

Do they use a Control fixed with the Glyoxal fixative?  If so, then how does the control look?  Just as weak? If not, I suggest using a control block that is fixed with the same fixative.  Just my 2 cents worth.
Have a good one.

Mark
 ----------
From:  lpwenk@mail.netquest.com[SMTP:MIME :lpwenk@mail.netquest.com]
Sent:  Friday, November 17, 2000 5:37 AM
To:  histonet@pathology.swmed.edu
Subject:  GLYOXAL AND IHC



 --------------------------------------------------------------------------  --
Need some help again.


Received a call. A histo lab has switched to a glyoxal fixative.


When they first perform an IHC on any of the tissues, for any antibody,
it works great.


If the lab goes back to the same BLOCK a couple of weeks later, and
cuts some more slides, the intensity of the staining is less.


If the labs waits a couple more weeks and cuts more slides from the
BLOCK, there is NO IHC staining.


Yet, the new BLOCKS (just processed) are staining great. So they know
that the antibodies are fine. But wait a couple of weeks on the new
BLOCKS,
and the same decrease in staining pattern repeats.


They thought it might be underfixation, so they have increased the
time in fixation, but the pattern is still repeating.


I know about decrease of staining on previously cut/stored SLIDES.
But has anyone experienced this on BLOCKS, for any antibody,
in just a couple of weeks time? Is it a fixation/processing problem
in general, or is it specific to glyoxal fixatives?


Any and all thoughts from the collective minds of Histonet are welcomed.
(and appreciated)


Peggy A. Wenk, HTL(ASCP)
William Beaumont Hospital
Royal Oak, MI 48073





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