Re: PTAH stain

<< Previous Message | Next Message >>,
Date:Fri, 27 Aug 1999 08:53:05 EDT
Content-Type:text/plain; charset="us-ascii"

Dr. John Shannon asks:

<<Does the PTAH stain have chloroform as one of its ingredients and, if so, 
there an alternative to the use of chloroform? Are other labs refusing to do 
this stain because of the chloroform and its association with liver damage?>>

PTAH (PhosphoTungstic Acid Hematoxylin) prepared in true and ancient form 
contains nothing but phosphotungstic acid (phosphowolframic acid) and 
hematoxylin. Conceivably someone may have added chloroform as a preservative. 
There were formulas that rapidly oxidized the hematoxylin, usually with 
permanganate, but the ritual is properly done by leaving the loosely 
stoppered bottle in the laboratory window (better on the fire escape) for at 
least six months.

PTAH requires primary Zenker fixation, with problems in disposing of both 
mercury and chromium. PTA is expensive, and the tungsten may also present 
disposal problems. These may all be reasons the reference lab doesn't want to 
do the stain.

It's a nice stain for pathologic glia and for muscle striations, but its 
chief use - since it took overnight to do - was to give the pathologist time 
to think up a name for a weird looking tumor (we didn't have immune stains 
back in the Jurassic Period). It was little used thirty years ago, and I 
never heard anyone express the blind faith in it expressed by Verdi's Aida 
("Omnipotente Ptah!")

Bob Richmond
Samurai Pathologist

<< Previous Message | Next Message >>