X-Message-Number: 5203
Date: Fri, 17 Nov 1995 09:54:11 -0800 (PST)
From: Joseph Strout <>
Subject: Re: damage assessment & ice microscopy

Richard Schroeppel wrote:

> We should be investigating ways to examine frozen tissue,
> without thawing it first.  The only technique I know of is
> freeze fracture; I've no clue as to its applicability.

Actually, cryomicroscopy is a rather common technique.  Tissue can be 
flash-frozen (with liquid propane, for example), resulting in mostly 
vitrified water, sliced (with diamond or glass knives) on a cryo-
ultramicrotome, and examined by transmission electron microscopy.  
Freeze-substitution (which you also hinted at in your post) is also a 
fairly common technique, though not one I have any experience with.

> Development of methods for examining frozen tissue would probably
> have other scientific uses besides cryonics.

It does, and it's in widespread use.  In fact, I have always assumed that 
when we're talking about examining tissue to evaluate a freezing 
protocol, we're examining it still in the frozen state.  Is this not true?

[For an intro to EM, including frozen preparations, check out "Electron 
microscopy in biology: a practical approach" by Robin Harris (1991).]

|    Joseph J. Strout           Department of Neuroscience, UCSD   |
|               http://www-acs.ucsd.edu/~jstrout/  |

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