Re: [Histonet] Hostonet Mallory Heidenhain stain

From:John Kiernan

You'll need to provide more details. Mallory's and
Heidenhain's methods are quite different, and both
require visual checking after the different steps.
This is particularly important with Heidenhain's
AZAN, which has two critical differentiations in 
the procedure. Whatever method you're using, the
cause of weak or uneven staining could lie with the
fixation of the tissue or the washing and
dehydration of the sections after any or all stages
of the staining procedure.

Fixation. Simple formaldehyde fixation is not
the best for trichrome methods. Treating the
hydrated slides with picric acid for a few hours
(followed by washing in water) before staining
improves the result. 

Your note implies a single staining solution - one of
the one-step trichromes like Gomori's or Cason's.
Such methods can work well, but the user has no 
control over the actions of the three anionic
dyes and the PTA (or PMA). Mallory and Heidenhain
must be turning in their graves, having their
names attached to a one-step trichrome - if indeed
that is the case. 

Washing & dehydration. Never wash in tap water after 
any step of any trichrome method. If it's neutral or 
slightly alkaline the water will extract the dyes and 
leave a messy result. The rinses should be in water 
that has been slightly acidified. (I put about 5ml of 
5% acetic acid in about 100 ml of tap water; no need 
to measure it!)

After the last rinse in acidified water, take the
slides into the first of 3 changes of new 100% alcohol.
Avoid "graded" alcohols because water-alcohol
mixtures can extract the dyes.
John A. Kiernan
Department of Anatomy and Cell Biology
The University of Western Ontario
London,   Canada   N6A 5C1
Sharon E Willman wrote:
> Hi,
> I am needing information on the Mallory Heidenhain staining procedure
> regarding washing out of the slides.  The tissues have been fixed in 10%
> formalin and processed through a routine processing schedule.  The
> slides are stained with the Mallory Heidenhain stain for 5 minutes and
> washed gently in running tap water for 30 seconds.  They are dehydrated,
> cleared and then coverslipped.
> If anyone has experience in this stain, I would appreciate any hints
> that you may be willing to share.
> Thanks in advance.
> Sharon Willman
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