X-Message-Number: 12447
From: Thomas Donaldson <>
Subject: To Doug Skrecky, about fixation
Date: Tue, 21 Sep 1999 23:40:29 +1000 (EST)

For Doug Skrecky:

Your scientific postings have improved a lot over the last few years.

However chemical fixation requires two kinds of experiment, both of which
you have not posted (and which may not exist).

First, we'd like to know if large organs can be completely fixed, and the
damage that may occur during such a process simply because it may take
some time. (Yes, some parts of a large organ can certainly be fixed, but
do we fix all of it? The use of some fixatives by embalmers doesn't really
answer this question).

Second, unlike the case of cryobiology, I at least am unaware of ANY case
in which an organ or tissue, even if small, has been first fixed and
then brought back to life. Failing this, it would help a lot to have
at least some more explicit idea as to how a fixed tissue (yes, folks, I'm
most interested in brains here!!!) might be revived. This may depend on
the particular fixative used --- it should, after all. But even if we
have no actual case of a fixed tissue being revived, it would at least
help to have some idea as to just how we might proceed to find a way
to reverse that fixation. 

And waving your hands in the general direction of nanotechnology isn't 
good enough. I'm asking for some more explicit ideas. As an explanation 
of my question, I'll point out that sometimes fossils will show remarkable
preservation of structure, even on a microscopic scale: but that
information remains insufficient to revive the fossil. The chemical 
transformations caused by fixation may destroy information we want to 
preserve, even if the result looks very like the original tissue.

Naturally we hope not, but hope is a fragile handle on the future.

			Best and long long life,

				Thomas Donaldson

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