Re: combining fixative /decalcifier
|From:||"J. A. Kiernan" <firstname.lastname@example.org>|
On Thu, 26 Oct 2000 email@example.com wrote:
> Have you tried Formical -4? It's a fixative and a decalcifier in one.
The "Form" in the trade-name implies either formldehyde (fixative)
or formic acid (an acid that can dissolve calcium phosphate
Fixation of proteins by formaldehyde is slow (days).
The actions of an acid dissolver of pathological calcifications
(or of bone) begins immediately, as the liquid diffuses into the
immersed object. Strong acidity (low pH) has certain "fixative"
actions, notably coarse coagulation of cytoplasmic protein.
These amount to bad fixation.
It has long been part of histo-lore that structural fixation
(which formaldehyde does well) should precede exposure to a
decalcifying acid (which will cause variable swelling, dissolution
etc in unfixed domains of a specimen). This is a sound principle.
John A. Kiernan,
Department of Anatomy & Cell Biology,
The University of Western Ontario,
LONDON, Canada N6A 5C1
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