[Histonet] histochemistry an extinct art?

[Bryan Llewellyn]

Immunohistochemistry is certainly the latest technique to coma along, and is 
undoubtedly of very great value.  It is now in its infancy, I suspect, and I 
fully expect that IHC procedures will increase in usefulness as time passes. 
Probably some antibodies will stop being used as clinical correlation with 
specific antobodies becomes more standardised.

However, the commonest method used in histolabs today is about 120 years 
old, or more.  That is the H&E.  There is no sign that it is going into 
"that long night".  Much the same can be said for Masson's trichrome and its 
clones, the PAS histochemical procedure, Perls' histochemical procedure. 
How do you demonstrate reticulin, or elastic?  Enzyme histochemistry is 
still used to demonstrate muscle fibre types.   The list could go on, but I 
am of the opinion that the older methods still have great value and will 
continue to have great value for a long time to come.  Sometimes they are 
far more convenient than IHC (toluidine blue for helicobacter, for 
instance), even when IHC is pushed for it.

Part of the reason is that IHC and enzyme histochemistry, for instance, 
demonstrate different things.  If an antibody against alkaline phosphatase 
is used, you will demonstrate the enzyme, i.e. the protein.  If you do an 
alkaline phosphatase stain using naphthol phosphate and a diazonium salt, 
you demonstrate the activity of the enzyme.  Those are two different things.

I know I am a bit of an old fogey on this, but I always strongly recommend 
that histotechs become conversant with the whole range of procedures used 
histologically, dye staining, histochemistry and IHC.

Bryan Llewellyn



----- Original Message ----- 
From: "Gudrun Lang" <gu.lang <@t> gmx.at>
To: <histonet <@t> lists.utsouthwestern.edu>
Sent: Friday, January 04, 2008 11:26 AM
Subject: [Histonet] histochemistry an extinct art?


> Hi,
>
> I have a question for those, that are experienced with the old and the new
> techniques in histotechnology. I looked through some antiquariat-books, 
> that
> deal a lot with histochemical demonstration of many tissue-compounds and
> enzymes. These techniques sound all very strange to me and it seems like a
> forgotten art.
>
> I work in a clinical histolab. Are the histochemical, enzymhistochemical
> methods still in use in research-labs? Did immunhistochemistry replace 
> them
> all together? Is histochemistry a part of modern cellbiology or just
> obsolete?
>
>
>
> Gudrun Lang
>
>


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