Re: PAS and Freida's comments

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To:Gayle Callis <>
Date:Thu, 08 Apr 1999 13:56:19 -0400
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The beautiful part about histology, is sometimes there is no right and
wrong and in accordance with the conversation on using blades and stains,
variety is the spice of life.  The important part is the end result.

The other beautiful part is the histonet and it's the never ending
contributions and opportunities for learning.

Thanks all,


Gayle Callis <> on 04/08/99 12:40:24 PM

Subject:  PAS and Freida's comments

I think it is also important to know what the pathologists might be looking
for, PAS for fungus, glycogen, basement membrane, mucin, etc indicate to
how I need to do the method.  In fact, when they ask for a PAS for fungus,
I use Chromic acid as the oxidizer, not perodic acid.

Let me count the ways to do PAS!!  I have more than one PAS protocol for
different things.

I also counterstain with hematoxylin for a shorter time, since the periodic
acid will enhance hematoxylin staining by converting the DNA/RNA COOH
to aldehydes, with the chance that you can overwhelm the PAS.  In fact,
is a way to restore hematoxylin staining when tissues have been stored in
NBF too long, and the pH changes.  A periodic acid step before hematoxylin
staining often restores the nuclear staining.

Full of sidelights today, must be Springtime!

Gayle Callis

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