Diane Coulter asks:

>>We use Dubosque-Brazil [Dubosq-Brazil fixative] for fixing kidney biopsies. 
The procedure is ancient and I have no references. Can anyone tell me why 
this is used for kidneys (formalin was used at my last job) and what is the 
optimum fixation time for a needle biopsy in this stuff. Is there a maximum 
amount of time the specimen should be left in it?<<

This is a complicated bibliographical problem I got some information on it 
about ten years ago, from Dr. Cohen, the author of the paper.

"Frozen-section analysis of allograft renal biopsy specimens: reliable 
histopathologic data for rapid decision making" in Arch Pathol Lab Med  
1991;115:386-389; April 1991. Cites Cohen's earlier "Masson’s trichrome stain 
in the evaluation of renal biopsies: an appraisal" in Am J Clin Pathol 
1976;65:631-64 which is supposed to contain the formula. He told me it's in 
Histopathology Laboratory Procedures, National Cancer Institute, a reference 
I've never seen. 

The ultimate reference is the venerable The microtomist’s vade-mecum (Bolles 
Lee): a handbook of the methods of animal and plant microscopic technique. 
11th ed. Gatenby JB and Beams HW, eds. Blakiston, Philadelphia, 1950. p. 325. 

It's spelled Dubosq-Brazil fixative, by the way.

The formula and information Dr. Cohen sent me is:

80% ethanol 150 mL
37% formaldehyde    60 mL
picric acid 1 g

Add 1 mL glacial acetic acid to 14 mL stock solution before use.

Leave in the fixative from 6 to 24 hours depending on the size of the tissue. 
Transfer to 70% alcohol to await processing for light microscopy.

When this post gets archived to Histosearch, I suggest you use it as your 
reference, with a printed copy of this post.

Bob Richmond
Samurai Pathologist
Knoxville TN
RSRICHMOND@aol.com
May 8th, 2002