We have adjusted several protocols over the years for this type of 
automation. Most recently we dispensed with a regressive technique and were 
able to improve consistency and shorten the staining protocol by about 15 
minutes.

Two suggestions: If you wish to stay with a regressive technique, try 
substituting aqueous acetic acid for acid alcohol. You may have to play 
with the concentration a bit but consistency is generally improved because 
small changes in the acetic concentration do not have the same impact as 
small changes in acid alcohol concentration--basically its more forgiving. 
When you are working with very weak acid alcohol it is difficult to 
maintain the same exact concentration from day to day.

Second, the mucin staining is a function of the Hematoxylin pH. Establish a 
rigorous QC for Hematoxylin before use. Lowering the pH (usually by adding 
acetic acid) can significantly reduce mucin staining. Automation of this 
type can really exaggerate even small differences in the Hematoxylin. 
noticeable differences occur with pH changes of as small as 0.2 either 
direction.

Bert Dotson

-----Original Message-----
From:	a i d a n   s c h u r r [SMTP:Aidan.Schurr@hvh.co.nz]
Sent:	Wednesday, October 04, 2000 9:52 PM
To:	histonet@pathology.swmed.edu
Subject:	blue mucin in H&E

Hi all,

We have recently switched to a linear staining system, which
requires set, identical time in each solution.  To facilitate this, the
concentration of the acid alcohol was lowered from 1% to 0.2%.
We are now experiencing blue staining of mucin in cervical, colonic
and gastric biopsies.  Any thoughts?!

Cheers
Aidan, New Zealand
___________________________________________________
shin: device for finding furniture in the dark...
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a i d a n   c   s c h u r r
     section head,  histology department
      hutt valley health
       high street
        lower hutt, new zealand

     ph.  ++64 4 5709173
     fax  ++64 4 5709214
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