decalcification with Perenyi's

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From:Gayle Callis <>
Date:Fri, 21 May 1999 08:53:57 -0600

Since Perenyi's is a dilute nitric acid containing alcohol (this helps
slow down decalcification) and dilute chromic acid, it would be slower
than using a higher concentration of nitric acid.  Actually, they should
be very happy to have good results.  You did not say HOW long it was
taking to decalcify the bone, trephine biopsies???  and what exact time
frame they are looking at, hours, rinse, process with next day sectioning
and staining. 

You could always try a commercial Hydrochloric acid solution, that has
12% or so HCl, but you may sacrifice the quality you already have now,
UNLESS you do endpoint determinations.  There are also nitric acid 
recipes that just contain water and the acid, with nitric at 5-10%, these
will be fast, but once again, control is important.  There are nitric acid
solutions available from vendors, based on known methods found in books.

RDO is a hydrochloric acid (high concentration of 15% or so) containing
some things that give it color (chromic acid??? etc) and works very
fast even WHEN you dilute 1:1.  Once again, that boring word - control.

It also helps to suspend the bone in decalcifier, and change the solution
daily as it becomes exhausted, rinse your bones between changes to wash
calcium (some resides on surface of bone during decalcification) off. Also,
put the bone in at least 20 times the volume of bone to solution.  Some 
will agitate decalcifier, but that is a debatable point.  

I think your key comment, have good results, would be grounds for NOT
changing your method.  Hopefully you can convince them all is well,
but a tidge late, if you used a formic acid decalcifier, they would still
be living with longer time frame.  No harm in that if it does not harm
the cells, soft tissues, staining, etc of the bone, a desirable thing
for diagnosis and subsequent treatment of a patient.

Gayle Callis

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