RE: mallory trichrome method

<< Previous Message | Next Message >>
From:"Gary W. Gill" <garywgill@email.msn.com>
To:"Marshall, Sharon, Mrs" <marshall@anat.uct.ac.za>, histonet@Pathology.swmed.edu
Reply-To:
Date:Fri, 09 Apr 1999 00:03:23 -0500
Content-Type:text/plain; charset="iso-8859-1"

If you're preparing Mallory's trichrome stain from scratch, be aware that
the PTA concentration may be critical.  Unless you take pains to ensure
reproducibility, you may encounter unpredictable staining results.  PTA
functions as a dye excluder, so that the operative acid dyes can stain
differentially.  If not enough PTA is present, the acid dyes will perform as
though no PTA is present and NOT stain differentially.

PTA is hygroscopic.  It naturally absorbs moisture from the atmosphere.  In
the worst case, it appears grossly to be like school paste of the kind
provided to me in the dark ages.  Bottom line: when you weigh out PTA with
much water and add it to a stain formulation, the stain will perform as
though no PTA has been added.  I've seen the effect in Pap EA formulations,
the origins of which are rooted in Mallory's trichrome stain.  In such
instances, the EA is awful.  Light green and eosin stain the same cells so
that they are muddy and totally unacceptable, instead of distinctly green
and red.

Therefore, dry PTA by removing the screw cap of the bottle and heating the
bottle in a warm oven overnight.  Prepare a 20%(W/V) solution of PTA in 95%
alcohol.  Thereafter, volumetrically, rather than gravimetrically, dispense
the volume required to provide the desired weight of PTA.  This approach is
convenient.  It avoids the hygroscopicity of PTA and facilitates stain
preparation.  Each 10 mL contains 2 gm PTA.  For my EA, for example, use 20
mL per 980 mL of solution to provide the recommended 4 gm per L.

Gary Gill

PS -- If anybody knows why Mallory had the insight to use PTA, I'd love to
know.  Why on earth would anybody choose PTA for this purpose?  Mallory must
have had a reason.

> Hi  histonetters,
>
> I wonder if anybody has the method for the mallory trichrome stain
> which uses acid fuchsin(red cells), phosphotungstic acid and aniline
> blue-orange G(muscle etc.). I have lost my method and I am not sure
> of the exact times of the tissue sections in each.
>
> Thanks
> Sharon Marshall
> e-mail: marshall@anat.uct.ac.za





<< Previous Message | Next Message >>