recovering endogenous biotin with antigen retrieval, casein blockers

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From:Gayle Callis <>,
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There has been a great deal of discussion on quenching endogenous biotin
supposedly brought back by antigen retrieval on NBF fixed tissues.  

Is there a reference to this?  I learned that this would happen from Jerry
Fredenburgh in one of his workshops.  What are your experiences with this?
Are people seeing this occuring in their immunostaining on a daily basis?
Someone did mention this during the discussion, sorry I deleted the
message.  This seems to come up in conversations about endog biotin
blocking, but is it merely conversation and casual, but scientific

Also, dry skim milk powder has been mentioned as a biotin blocker?  Reference?

Someone brought this up the other day, could they reiterate the reply,
expand further. 
and does this include casein??? 

My replies concerning the retrieval and dry milk is what I learned from
others, not based on an actual referencing, but it may be there.  

My blocking of endogenous bitoin (using an avidin/biotin kit) is based on
the reference

Wood and Warnke, J Histochem Cytochem, 29(10):1196-1204, 1981 Suppression
of endogenouse avidin binding activity in tissues and its relevance to
biotin-avidin detection systems.  

Gayle Callis
Veterinary Molecular Biology
Montana State University
Bozeman MT 59717-3610
406 994-4705
406 994-4303

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