[Histonet] Bouin's fixation/removal of picric acid

[John Kiernan]

I didn't phrase my question very clearly, and
should have explained the reason for asking.
 
Previously I've encountered lithium carbonate
for removing picric from sections. It's the 
traditional thing to do after Bouin fixation
when the tissue is still yellow in the wax 
and after hydration of the sections.
You can easily see when all the yellow has
gone. 

With a block you can't see the middle, and 
I was wondering how long it takes until no
more yellow comes out into the liquid. With
70% and higher alcohols alone it seems to take 
for ever (at least with 5 mm and larger specimens; 
I haven't used tiny biopsies after Bouin fixation). 
It would be nice to have an idea how much more 
quickly the picric acid is extracted when the 
70% alc is saturated with Li2CO3.

I asked about removing the Li2CO3 because it's
almost insoluble in alcohol (Merck Index). That
would be 95-100% alc. I guess you rinse the
specimens in more 70% after extracting the 
picric acid, and that removes the Li2CO3 and
you don't get damage from crystals forming in
the tissue.
-- 
-------------------------
John A. Kiernan
Department of Anatomy and Cell Biology
The University of Western Ontario
London,   Canada   N6A 5C1
   kiernan <@t> uwo.ca
   http://publish.uwo.ca/~jkiernan/
_________________________
Sarah Jones wrote:
> 
> I use it on wet tissue, it does not appear that the lithium needs to be
> removed.  Maybe I'm not understanding your question.   Sarah
> Ref. Theory and Practice of Histotechnology, Sheehan, Hrapchak, page
> 47.
> 
> >>> John Kiernan <jkiernan <@t> uwo.ca> 09/14/03 11:54PM >>>
> Sarah, do you use the saturated lithium
> carbonate in 70% ethanol on blocks of
> tissue or on hydrated paraffin sections
> that are yellow?
> 
> If it's for blocks, how do you remove
> lithium carbonate from the decolorized
> specimens?
>               John Kiernan
> --
> -------------------------
> John A. Kiernan
> Department of Anatomy and Cell Biology
> The University of Western Ontario
> London,   Canada   N6A 5C1
>    kiernan <@t> uwo.ca
>    http://publish.uwo.ca/~jkiernan/
> ___________
> Sarah Jones wrote:
> >
> > I've always used saturated lithium carbonate in 70% ethanol to
> remove
> > the picric acid.  I believe it would be faster and more complete
> than
> > 70% alone.
> >
> > Sarah Jones HT(ASCP)
> > Dept. of Vet. Anatomy & Public Health
> > Histology Lab
> > Texas A&M University
> > College Station, TX 77843-4458
> > phone: 979-845-3177
> > fax:  979-458-3499
> >
> > >>> "peptolab" <peptolab <@t> hamptons.com> 09/13/03 08:32AM >>>
> > A 3-5 mm testicular biopsy should be fixed in one to two hours. Be
> sure
> > to
> > rinse out as much yellow picric acid as possible (you can use
> running
> > water
> > or 70% alcohol ). The basophilia of chromatin in the stored block
> will
> > deteriorate after some time if there is picric acid  residue.
> >
> > Jeff Silverman HT HTL QIHC (ASCP)
> > Southside Hospital
> > Bay Shore NY
> >