Out of curiosity, I just looked at some Bouin's-fixed lamprey muscle under my
fluorescent scope and it wasn't autofluorescent in my rhodamine,
fluorescein or
DAPI filter sets.  So I don't think the picric acid in your fix is the
problem.
In fact, one might worry that the picric acid would instead quench the
fluorescence of your signal, particularly if it imparts a yellow color to the
tissue.  In general, chromogens and metals tend to quench fluorescence.

Karen Larison



Date:          Tue, 22 Dec 1998 08:54:56 -0500
From:          "Michael J. Lyon, Ph.D." <lyonm@VAX.CS.HSCSYR.EDU>
Subject:       Autofluorescence
To:            "Histonet (E-mail)" <HistoNet@Pathology.swmed.edu>

Hello:

I have just started doing immunostaining of muscle dissections.  The tissue
has
been immersion fixed in 4% paraformaldehyde 0.2% Picric acid for about 24 hrs
at 4C.  My primary antibodies are all fa
rly dilute at 1:3000 or 1:4000, secondary is at 1:400 and I am using CY3 at
1:600.  I have tried ammonium chloride and sodium borohydride but still have
considerable background from the muscle fiber
.  I was thinking of switching to a different fixation.  Any suggestions would
be appreciated.  Hope I have given sufficient info.

Thanks in advance

Michael