Hi Betsy,
	I used to fix in something very similar at 4oC for 24hr with NO ill
effects.
	The tissue can be held in 70% EtOH for as long as you like.  I've
had tissues in 70% for over a decade with no apparent ill effects on
structure (and some histochemistry) as long as I prevented evaporation.
	If you must use MeOH rather than EtOH in Carnoy's, then the decision
about the processor dehydrants should be totally dependent on the reason you
used for the substitution of MeOH in the first place.(see Note!)  

Note:  If one fixes in a solution that is devoid of HOH for a substantial
period of time and does so with changes of the fluid, might one not consider
the possibility that the tissue is dehydrated by the end of the process?

Regards,

Fred Monson

Frederick C. Monson, PhD   
Center for Advanced Scientific Imaging
Schmucker II Science Center
West Chester University
South Church Street and Rosedale
West Chester, Pennsylvania, USA, 19383
Phone:  610-738-0437
FAX:  610-738-0437
fmonson@wcupa.edu
CASI URL:  http://darwin.wcupa.edu/casi/
WCUPA URL:  http://www.wcupa.edu/
Visitors URL:  http://www.wcupa.edu/_visitors/


> ----------
> From: 	Molinari, Betsy
> Sent: 	Wednesday, June 19, 2002 11:08 AM
> To: 	Histonet@pathology.swmed.edu
> Subject: 	FW:
> 
>  
>  
> -----Original Message-----
> From: Molinari, Betsy 
> Sent: Wednesday, June 19, 2002 8:45 AM
> To: 
> Subject: 
>  
> Good day all,
>  I understand that tissue being fixed in Carnoys should not remain in the
> fixative more than 4 hrs. If the tissue will not be able to be processed
> for several hrs after that, can the tissue be held in 70% ETOH . Also if
> methyl alcohol is going to be used in the Carnoys instead of ethyl do all
> the alcohols used in the processor need to switched?
> Thanks,
> Betsy Molinari HT (ASCP)
> Texas Heart Institute 
> Houston,Texas
> 832-355-6524
>