Jay Cheung asks about a silver stain and fluoro-jade.

1. Regarding the silver method, there are lots of these and
you'll need to provide more details, including a reference to 
the publication that describes the method you're using. 
Probably someone out a-histonetting will have experience
with the same technique. Also, there is a special issue of 
J. Histotechnol. (Sept 1996) devoted to silver techniques, 
how they work, problems with them etc.

2. Fluoro-jade is a trade secret, revealed only as an anionic
xanthene dye. That tells you it's in the same group as
fluorescein and eosin. It stains dead and possibly also
moribund neurons (LC Schmued et al 1997 Brain Research
751:37-46).
It is a property of dead neurons and other cells that they stain
with anionic dyes. They stain with eosin Y, for example, in
H&E preparations (and it's worth noting that eosin is a good 
fluorochrome). Acid fuchsine is also useful for this purpose
(RN Auer et al 1984 Acta Neuropath 64:177-191), and its
mechanism of action has been partly elucidated (see Biotech.
Histochem. 73:244-254, 1998). Unless someone has done a
comparative study and shown that fluoro-jade is somehow superior
to eosin (and I'm pretty sure nothing like this has been
published), 
is it justifiable to use an unidentified secret substance in 
scientific work? Recently it has been shown that fluoro-jade 
stains reactive astrocytes as well as degenerating
neurons (JA Colombo & VI Puissant 2002 J. Histochem. Cytochem.
50:1135-1137). This is hardly surprising; anionic dyes do stain
cytoplasmic proteins, and reactive astrocytes are full of
cytoskeletal filaments.

3. One final point - just in case you were trying to do silver
and fluoro-jade on the samme sections, it probably won't work,
because exposure to heavy metal ions quenches fluorescence.
-- 
-------------------------
John A. Kiernan
Department of Anatomy and Cell Biology
The University of Western Ontario
London,   Canada   N6A 5C1
   kiernan@uwo.ca
   http://publish.uwo.ca/~jkiernan/
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jay cheung wrote:
> I am currently running silver staining and fluoro-jade staining
> for detecting neuronal degeneration in rat brain fixed and
> fresh frozen sections.  I never ran these procedures before and
> the results I got from the first trial showed many non specific
> staining not limited to degenerating neurons.  Also, it seems
> like the PFA fixed tissue got more silver stain than the fresh
> post-fixed tissue.  Can someone tell me the mechanism of action
> of these staining procedures and what are the tricks about
> these procedures.  I did some research myself and so far have
> no luck finding out the answers for these questions.  I used FD
> silver stain kit to do the silver stain.  Thank you so much for
> your help!
> 
> Jay
> 
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