[Histonet] Ethanol or acetone fixation

[John A. Kiernan]

No, the mechanisms are quite different. Alcohol,
acetone and formaldehyde are all water-soluble
fixatives.

Formaldehyde attaches to protein molecules and
(given some time) links them together. Alcohol
or acetone coagulates protein, changing the
shapes of the molecules but not their chemical
properties. Coagulant fixatives do their work
instantly as they penetrate the tissue. 
Formaldehyde (a smaller molecule than ethanol
or acetone) penetrates rapidly but needs 12-24
hours to stabilize the structure. Mixtures 
containing both alcohol and formaldehyde can
provide the advantages of both types of
fixation. Such mixtures usually contain some
acetic acid as well, which coagulates nuclear
chromatin and opposes the shrinking action of
the alcohol. See
http://publish.uwo.ca/~jkiernan/formglut.htm
for more about how formaldehyde works.
-- 
-------------------------------
John A. Kiernan
Department of Anatomy and Cell Biology
The University of Western Ontario
London,   Canada   N6A 5C1
   kiernan[AT]uwo.ca
   http://publish.uwo.ca/~jkiernan/
   http://instruct.uwo.ca/anatomy/530/index.htm
_______________________________
DrEssy wrote:
> 
> Hi,
>  I was wondering if anyone knows how acetone and/or alcohol fixation works?
> Does it work in a similar manner as water soluble fixatives such as
> formalin?
>  Thanks!
>   -Essy
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