A talk with DAKO technical services can also help you with their 
chromogens.  There is also a endog alk phos quenching solution from KPL, 
called Universal Blocker, and is used in very beginning of the staining 
protocol.  It is ready to use and very nice, short, and very convenient. If 
you use this, levamisole is not needed (added to chromogen substrate which 
with ready to use chromogens, always worried me as a dilution factor) - in 
fact we tried the universal block in conjunction with levamisole to see 
effects and noticed lessening of red color or signal, not what we 
wanted.  So you would have to use one or the other. I suggest you try the 
KPL blocker -

If you are running your primary antibody at the same concentration for all 
these chromogens, you will notice a difference.  This is something Chris 
van der Loos teaches in his multiple staining workshop but still applicable 
to single IHC work -  about the efficiency of chromogens compared to 
antibody titer.  With DAB you would have less conc primary than with new 
fuchsin, although Permanent red is approaching DAB for efficiency, some 
would call it sensitivity.

At 07:30 PM 9/29/2004, you wrote:
>I have been having some trouble with some Abs stained with New Fuchsin
>and permanent red. Recently I was asked if I were using Levamisole in
>the permanent red and if so how much? I was told too much Levamisole in
>permanent red would result in no staining. I have used 1 drop per ml for
>both New Fuchsin and permanent red, which is the appropriate amount.  We
>have run both DABS and either permanent  red or New Fuchsin with the
>same AB from the same vial with vastly different results. Any ideas?
>Rena Fail
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Gayle Callis
MT,HT,HTL(ASCP)
Research Histopathology Supervisor
Veterinary Molecular Biology
Montana State University - Bozeman
PO Box 173610
Bozeman MT 59717-3610
406 994-6367 (lab with voice mail)
406 994-4303 (FAX)



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