[Histonet] H&E to PAS restaining protocol

[John Kiernan]

Russ Kerschmann MD wrote:
> Can anyone provide a protocol for reprocessing an H&E
> slide into a PAS slide?  Can the reverse also be
> performed?  

Easy! Here's a procedure. I'm not happy about
calling this kind of thing a "protocol" because
it needs observation and judgement if it's to
work properly. You should do this job yourself;
do not entrust it to someone else.

1. Remove the coverslip and mountant and 
   take the section to 70% alcohol. Don't 
   rush any step of this procedure, and be
   especially certain that you have
   dissolved out all the mounting medium.
2. Immerse in acid-alcohol until all the
   haemalum nuclear (and any other blue)
   staining has gone.
3. Rinse in 70% alcohol, then in water.
4. Put in slightly alkaline water until
   the eosin colour (pink) has all gone.
     (Note. You will probably not be able
   to extract eosin from a few strongly
   basic materials present in some animal
   tissues: eosinophils, Paneth cells and
   spermatozoa.)
5. Wash in tap water, then in distilled
   water before doing the PAS method.

>How can the risk of losing the tissue be
> minimized?

Keep exposure to alkalinity (Step 4 above)
to a minimum. Hard tap water may be 
sufficient, or you can add a small drop of 
ammonium hydroxide, or of saturated aqueous 
lithium carbonate. High pH removes sections
from slides.
 
> Many thanks, and Happy Holidays.

Which holiday(s)? The next one on my calendar is
Nobel Day (Sweden) on 10th December, followed by
Our Lady of Guadalupe (Mexico & Central America)
2 days later. Chanukah isn't until the 19th.
Or do you mean happy Christmas? It's still
25 days away!

Hope this helps.
-- 
-------------------------
John A. Kiernan MB, ChB
Department of Anatomy and Cell Biology
The University of Western Ontario
London,   Canada   N6A 5C1
   kiernan <@t> uwo.ca
   http://publish.uwo.ca/~jkiernan/