Dear Patrick,

	This technique sounds similar to freeze sublimation methods used in
electron microscopy.  The idea is that the ethanol replaces the water &
therefore reduces/eliminates artifact caused by ice crystal formation
during freezing.  Normally however, the process would be completed to
remove all water.

	The idea is that the morphology of the tissue (in EM its still only 1mm3)
is precisely preserved.  How the tissue has been treated prior freezing in
70% ethanol affects the result.  For routine histo samples the normal size
of the sample may be too large.

	As to staining & IHC excellent morphology in EM usually means awful/no
immuno, but histochemical reactions should be OK.

	Regards

	Rob W.

At 05:07 PM 6/29/99 -0700, you wrote:
>Has anyone out there in Histoland ever heard (or perhaps done this) of
>placing tissue in 70% ethanol, and then freezing to -80 degrees C? I was
>speaking to a researcher today, who has some tissue  (bone with soft tissue
>I believe) samples stored in this manner.
>My first fear is artifact from the freezing/thawing process.
>How does this storage effect staining, both special and IHC?


R. Wadley, B.App.Sc, M.L.S
Laboratory Manager
Cellular Analysis Facility
School of Microbiology & Immunology
UNSW, New South Wales, Australia, 2052
Ph (BH) 	+61 (2) 9385 3517
Ph (AH)	+61 (2) 9555 1239
Fax 	+61 (2) 9385 1591
E-mail	r.wadley@unsw.edu.au
www	http://www.unsw.edu.au/clients/microbiology/CAF.html
	(Under development)