AW: [Histonet] Mucin blocking reagent for IHC

[John Kiernan]

That's a good point. The original question did not mention whether a polymer-based detection system was being used.

John Kiernan
Anatomy, UWO
London, Canada 
= = = =
----- Original Message -----
From: Gudrun Lang <gu.lang <@t> gmx.at>
Date: Monday, December 15, 2008 9:22
Subject: AW: [Histonet] Mucin blocking reagent for IHC
To: 'John Kiernan' <jkiernan <@t> uwo.ca>
Cc: histonet <@t> lists.utsouthwestern.edu

> With the polymer-systems of IHC detection it is often seen, that 
> in some
> tissueparts an unwanted background occurs. It is said, that the large
> polymers are trapped in OH-reach tissues like mucin and 
> collagen. And also
> an additional washing step doesn't erase that. The polymers are 
> labelledwith Peroxidase. The trapped peroxidase leads to the 
> colourdevelopement.
> Gudrun Lang
> Histolab
> Linz, Austria
> 
> -----Ursprüngliche Nachricht-----
> Von: histonet-bounces <@t> lists.utsouthwestern.edu
> [mailto:histonet-bounces <@t> lists.utsouthwestern.edu] Im Auftrag 
> von John
> Kiernan
> Gesendet: Montag, 15. Dezember 2008 07:15
> An: Aprill Watanabe
> Cc: histonet <@t> lists.utsouthwestern.edu
> Betreff: Re: [Histonet] Mucin blocking reagent for IHC
> 
> Please explain "mucin trapping the DAB". Are you sure that this 
> is not
> genuine immunohistochemical  localization of the antigen?
> 
> At neutral pH DAB cations are attracted to tissue polyanions (in 
> mucus,cartilage etc). The attracted DAB should not be oxidized 
> to a brown
> insoluble polymer in the absence of peroxidase.
> 
> The only working peroxidase molecules in an immunohistochemical 
> preparationshould be those specifically bound at the site 
> recognized by the primary
> antibody. Brown staining of mucus suggests the presence of 
> peroxidase in the
> DAB-H2O2 final incbation solution. This would catalyze the 
> oxidation of
> tissue-bound DAB. More washing after the last HRP-containing 
> reagent might
> help.
> 
> John Kiernan
> Anatomy, UWO
> London,  Canada
> - - -
> ----- Original Message -----
> From: Aprill Watanabe <awatanabe <@t> tgen.org>
> Date: Friday, December 12, 2008 17:26
> Subject: [Histonet] Mucin blocking reagent for IHC
> To: histonet <@t> lists.utsouthwestern.edu
> 
> > I am staining CA19-9 on pancreas and have a good amount of 
> mucin 
> > trappingthe DAB.  Is there a product that either blocks 
> > mucin or something else that
> > will limit the mucin effect?
> > 
> > Aprill Watanabe, B.S.
> > Research Associate
> > Integrated Cancer Genomics Division
> > Tissue Microarray Center (TMA)
> > Translational Genomics Research Institute (TGen)
> > main: 602-343-8822
> > Fax: 602-343-8840
> > awatanabe <@t> tgen.org
> > www.tgen.org
> > 
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> > http://lists.utsouthwestern.edu/mailman/listinfo/histonet
> 
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