Re: [Histonet] Help

From:Gayle Callis


There is no concentrated buffered formic acid recipe.  IF you calculate %
formic acid in commercial solutions or from a recipe, it is only ~4.5%.
Buffered formic acid is good if you want to do IHC, however, it is
published on effects of decalcification that concentrated acid decalcifies
rapidly, and that in itself protects antigen.  

Make up your own formic acid decalcifier, it does NOT have to be buffered
as long as you have bone that is totally fixed in NBF.  The main thing is
to do a decalcification endpoint check to insure bone is not overexposed to
your acid decalcifier.  

You can use 10- 15% formic acid, made from 90% stock solution.  15 mls of
90% stock formic acid and qs to 100 mls with distilled water. Use at least
20 times volume of solution to size of bone.  

Ways to speed up decalcification with 15% formic acid

Reduce size of bone, cut into slabs 5 mm thick, too thin is not good for
paraffin sectioning, bone will chip out of block. Do not stir if you do a
chemical endpoint test.  You need to take aliquot off bottom of container.
Do not put two pieces of bone in same solution when doing this.  Hopefully
you have xray for endpoint check, most sensitive method, excellent,
although chemical or a weight loss/weight gain method will work. 

Suspend bone in a bag, cheesecloth in the decalcifier.  Rinse bone next day
briefly to get calcium residing on surface of bone off and CHANGE to fresh
decalcifier to replenish formic acid. 

   At 11:26 AM 6/9/2004 -0400, you wrote:
>Hello Histonetters:
>I am looking for a buffered formic acid decal solution that will work 
>fairly rapidly for femoral head and stifle joint bones from several 
>different species.  I would be grateful to all who are willing to share 
>product name,where it can be obtained,  time in solution and  processing 
>Much Appreciated,
>Tish Floyd
>Latitia .E. Floyd @ GSK.Com
>709 Swedeland Road
>Safety Assessment
>King of Prussia, PA
>Tel: 610-270-7629
>Fax: 610-270-7202
>Pager: 610-963-6688
>Histonet mailing list
Gayle Callis
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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