Does anyone know why a buffered picric-formaldehyde
mixture is commonly called Zamboni's fixative? To the
best of my knowledge, the first published description 
was by Stefanini, De Martino & Zamboni, Nature 216:173-174
(1967) for fixing spermatozoa for EM. There is also a
1967 abstract by Zamboni & De Martino (J Cell Biol
35:148A) that does not give enough information to
allow one to make up the fixative. The enhanced preservation
of antigens for immunohistochemistry was published by
Accini, Hsu, Spiele & De Martino in 1974 (Histochemistry
42:257-264). Thus, the author most associated with the
development of this fixative was not L. Zamboni but 
C. De Martino. Or have I missed something in the
literature? That's quite possible.

Picric acid has been included also in buffered mixtures
with formaldehyde and glutaraldehyde for fixation for
EM immunohistochemistry (various publications, different
authors, early 1980s). Whatever the picric acid does 
in these mixtures, it does not work the same way as 
in Bouin's and other acidic solutions. Neutralized
picric acid does not precipitate proteins. Protein 
precipitated by picric acid can be redissolved by 
raising th pH to a near neutral level. Neutral picrate 
doesn't work as a dye either. In contrast to Bouin-fixed 
specimens, pieces of tissue fixed in neutral 
picrate-formaldehyde readily lose their yellow colour 
(which is quite weak initially) when washed in water.

Has there ever been a comparative study to find out
if picrate ions in neutral buffered aldehyde fixatives
really improve subsequent immunostaining? Could it
all be histomythology?
-- 
-------------------------
John A. Kiernan
Department of Anatomy and Cell Biology
The University of Western Ontario
London,   Canada   N6A 5C1
   kiernan@uwo.ca
   http://publish.uwo.ca/~jkiernan/
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"Morken, Tim" wrote:
> 
> Zamboni's is a variant of Bouin's fixative developed for EM use to fix
> spermatazoa and as such it contains picric acid. It is also a good fixtive
> to preserve antigenicity for EM. I haven't heard of it's use simply to keep
> sections from falling off slides, but maybe the procedure was written before
> the advent of coated slides and Plus-treated slides. Zambonis will coagulate
> protiens, so maybe that is why sections would stay on the slides a bit
> better than formaldehyde-treated sections. Other than that I can't think of
> a reason to use it.
> 
> Tim Morken
> Centers for Disease Control
> Atlanta, USA
> 
> -----Original Message-----
> From: David Van Reyk [mailto:David.VanReyk@uts.edu.au]
> Sent: Wednesday, January 08, 2003 6:14 AM
> To: histonet@pathology.swmed.edu
> Subject: zamboni vs straight paraformaldehyde
> 
> happy new year to all,
> [I think my firts attempt at posting this inquiry failed]
> we have been provided with an immunohistochemical protocol for forzen
> sections that requires Zamboni's fixative. In our lab we normally use 4%
> paraformaldehyde. The protocol mentions that zamboni's is used to keep the
> sections from falling off the slides. Is this the only reason Zamboni's
> would be used over straight paraformaldehyde or are there other advantages.
> 
> Dr David van Reyk,
> Dept Health Sciences,University of Technology,Sydney,
> PO Box 123, Broadway, NSW 2007, AUSTRALIA
> Ph 61-2-9514-2221 FAX 61-2-9514-2228
> email david.vanreyk@uts.edu.au
> http://www.science.uts.edu.au/health
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