[Histonet] staining query

[John Kiernan]

For your first question, Yes. The brown product of oxidation 
of DAB is not extracted or otherwise damaged by acidity
and/or alcohol, so you can safely differentiate an overdone 
haemalum counterstain.
 
For your second question, distinguishing multinucleate giant 
cells from muscle, how about lightly counterstaining with
eosin Y after the haemalum? You'll then have an H&E
preparation in which those cell types should look quite
different. You didn't say what antigen you're immunostaining,
or where it is. If it's in the cytoplasm of either muscle fibres
or giant cells (osteoclasts? TB? foreign body?), the other 
other cell-type should be recognizable even if the eosin
pink in immunopositive cells is obscured by the brown 
DAB oxidation product. 
 
A green anionic dye such as fast green FCF could be used 
instead of eosin, especially if the immunopositive material
is in distinct granules, fibrils or other domains within the
cytoplasm. Green with brown makes a more pleasing 
contrast than pink with brown.
 
John Kiernan
Anatomy, UWO
London, Canada.
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----- Original Message -----
From: louise renton <louise.renton <@t> gmail.com>
Date: Friday, July 13, 2007 21:49
Subject: [Histonet] staining query
To: Histonet <@t> lists.utsouthwestern.edu

> Hi all,  I have 2 questions to ask.
> 
> The first is...If I have counterstained my immuno too heaviliy with
> haematoxylin, can I decolourise with acid alcohol & restain or 
> will it
> affect the DAB?
> 
> The second is.....Is there a  tinctorial stain I can use to 
> differentiatemultinucleated giant cells from muscle? I cannot 
> use immuno, as the tissue
> has been badly treated (poor things) and thus IHC is muddy & yucky.
> 
> Thank you, best reagrds & have a great weekend
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