Hi Ruth,
	Is it better late than never, or have you all already forgotten?
	There is a method by which biological hoods are decontaminated
periodically.  What is done - by an EXPERT who can do algebra, use a balance
and is most importantly BONDED!!! - is as follows.  After calculating the
volume that must be contaminated, the hood (or building!!!) is sealed and a
hot plate on which is set a metal dish(?) is loaded with sufficient
Paraformaldehyde to provide the necessary Formaldehyde to decontaminate the
thing.  Then, the final seal is provided and the hot plate is turned on to
approx 100oC.  The Paraformaldehyde depolymerizes rapidly under the
influence of the heat, and the hood is left until the timer goes off.
That's it.  You could also use glutaraldehyde - search "glutaraldehyde
sterilization" in Google.   Also you can search "paraformaldehyde
fumigation" or "formaldehyde fumigation".  Also look here:
http://www.oie.int/eng/normes/mcode/A_00138.htm and search on the page for
"formaldehyde".  You'll see that HCHO is use to sterilize hatching eggs.
	You have merely taken the next step in a long-standing use of
formaldehyde as a fumigant sterilizer.

Regards,

Fred Monson

P.S.  I only mention the following because I have used the item when cutting
clinical specimens in a research protocol.  URL:
http://www.instrumedics.com/cryovacaway.htm {I have no other relationship to
Instrumedics than as a contented customer.} Even with this, I had to clean
the thing every once in a while.

Frederick C. Monson, PhD   
Center for Advanced Scientific Imaging
Schmucker II Science Center
West Chester University
South Church Street 
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: 	Cazares, Ruth
> Sent: 	Thursday, December 27, 2001 11:52 AM
> To: 	'histonet@pathology.swmed.edu'
> Subject: 	Cryostat Disinfecting
> 
> Hello fellow Histonetters,
> 
> A question has arisen in our Histo lab as to what methods are being used
> to
> disinfect cryostats.
> In the past I have used formalin in a small container put in the cryostat,
> during the defrost cycle at night the formalin will thaw and the vapors
> act
> to disinfect.  Where did this originate? And what other methods are being
> used?  Inquiring minds want to know.  Any information is greatly
> appreciated.  Thanks !
> 
>