Re: mast cells, controls

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From:Jeff Silverman <peptolab@hamptons.com>
To:"Hewlett Bryan (CMH)" <HEWLETT@EXCHANGE1.CMH.ON.CA>, "'histonet@pathology.swmed.edu'" <histonet@Pathology.swmed.edu>, "'Hedley David Glencross'" <hedley@hheath.demon.co.uk>
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Date:Fri, 28 May 1999 17:52:22 -0400
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With regard to mast cells, I'm always looking at mesenchymal and
histiocytic tumors of human skin and in my experience dendritic connective
tissue mast cells also stain for CD68 (KP-1) a lysosomal glycoprotein. In
fact, I'm having to do toluidine blue (which gets most of the stromal mast
cells,no?) to distinguish these from the histiocytes (some CD68+) and
dermal dendritic cells (CD68 negative)  in a series of histiocytomas. 
Haven't noticed many mucosal (epithelial?) mast cells in skin though. 

I like to use end mounted individual controls. For our commonly performed
stains, (like alcian blue on Gastroesophageal  junction and esophagus,
iron, PAS, mucin. etc, I choose a block from that day's work, (eg a small
colon polyp for alcian blue/muci) and pickup some extra sections. That way,
I can pick up a section on the end of each special slide,each has its own
control. I also keep common control blocks handy and do this with ER/PR/Her
2 neu, iron, retic, fungus etc. Mine is a one person lab so the object
holder, knife angle, etc are NEVER changed so control blocks last forever
cutting one or three at a time each day. Doesn't really add to cutting time
too much and controls are always fresh. I've had already cut AFB's go bad
and some epitopes deteriorate in cut sections. 

Let's everyone take a chill pill and enjoy the spring minivacation.   Jeff
Silverman
----------
> From: Hewlett Bryan  (CMH) <HEWLETT@EXCHANGE1.CMH.ON.CA>
> To: 'histonet@pathology.swmed.edu'; 'Hedley David Glencross'
<hedley@hheath.demon.co.uk>
> Subject: RE: mast cells
> Date: Friday, May 28, 1999 9:00 AM
> 
> Hedley,
> 
> 	It's true that some dye based methods are more rapidly performed,
> including the non-metachromatic alcian blue. The superb long toluidine
> blue technique of Wingren and Enerback, which is used to unmask GAG's
> blocked by formaldehyde fixation, certainly isn't as rapid as IHC. 	
> 	Are they as good? It depends on the purpose for doing the stain. If
> your intent is to quickly check for the presence of mast cells, then
> maybe. If you wish to determine whether the number of MC is increased or
> decreased, then absolutely not.
> 	One should consider that there two major sub-populations of mast cell,
> which differ considerably in their stainability, depending on the
> staining protocol and the fixative used. Connective tissue mast cells
> are probably the easiest to stain with traditional dye technology.
> Mucosal mast cells can be more problematic, particularly with
> formaldehyde fixation. 
> The number of mast cells demonstrable varies with the technology used.
> In human material, immunohistochemistry for CD117 or Mast cell tryptase
> will reveal the greatest number( in rat RMCPI or RMCPII). Dye
> technology, independent of fixative, will only stain approximately
> 60-90% of mast cells ( paper submitted). A simple experiment should
> convince you. Stain separate sections from  small bowel with you
> favorite dye method and with AA1, perform a mast cell count on the
> lamina propria with each stain, the result may astound you.
> 
> Valuable insight into the staining of mast cells can be gained from
> chapter 24, p695, by Lennart Enerbach. In "Histochemistry in
> Pathological Diagnosis". Editor Samuel S. Spicer. 1987. Marcel Dekker
> Inc. NY. ISBN 0-8247-7408-6.
> 
> I'm sure that mast cell guru John Kiernan will jump in to add his
> insightful comments (how about it John?).
> 
> Regards
> 
> Bryan
> >----------
> >From: 	Hedley David Glencross[SMTP:hedley@hheath.demon.co.uk]
> >Sent: 	May 24, 1999 1:56 PM
> >To: 	histonet@pathology.swmed.edu
> >Subject: 	mast cells
> >
> >Hi everyone
> >
> >I have used AA1 for mast cells myself, and found it good. But I would
> >ask, why use ICC (IHC) when metachromatic methods using thionin or
> >toluidine blue are just as good and much quicker?
> >
> >Yours puzzledly
> >-- 
> >Hedley David Glencross
> >
> >



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