Tony,

We cut mouse and fish embryos embedded in agar.  We find that these cut well on one 
of our cryostats, but not on the other.  We've concluded that the "bad" cryostat 
doesn't hold its temeperature very well, so that at the bottom of the temperature 
excursion, the block shatters, whereas as at the top of the excursion, it  
compresses.  I also have a postdoc who routinely cuts rat brain on the "bad" 
cryostat, and he drops the temperature a bit, and uses Joyce's thumb trick, and finds 
he can overcome the inherent problems of cutting in this cryostat.  I hope this 
helps.

Karen in Oregon



Date:          Wed, 08 Mar 2000 11:20:12 -0700
From:          Joyce Kotzuk <JKotzuk@salud.unm.edu>
Subject:       Re: Cryosectioning
To:            tony.whyte@bbsrc.ac.uk, histonet@pathology.swmed.edu

Tony, When I used to section fresh frozen mouse or rat brains, I would place my 
gloved thumb on the face of the block for a few seconds to warm it ever so slightly 
just before taking a section. This
would prevent breakage of the section, or "chatter" as w
e called it, and produce a beautiful, complete and untorn section. Maybe this little 
tip will help you.
Joyce Kotzuk, UNM pathology dept.

>>> "tony.whyte" <tony.whyte@bbsrc.ac.uk> 03/08/00 08:21AM >>>
Hi all,

i'm having trouble sectioning whole frozen mouse embryos.  They were snap
frozen in isopentane in liq N2 and mounted in OCT on cork.  The trouble is
either that the section is compressing or else fragmenting.  Using a new knife
hasn't helped the problem.  Any ideas?

Tony W.
Cambridge