X-Message-Number: 5835
From:  (Thomas Donaldson)
Subject: Re: CryoNet #5707 - #5709
Date: Mon, 26 Feb 1996 12:12:09 -0800 (PST)

To Ralph Dratman:

So far as I understand cryobiology, IN THEORY a very fast freezing would be
appropriate. But no one has come even close to working out how to freeze a 
human head fast enough; in practise it is a non-question.

Obviously if we can't do it we have no way of testing it, one more reason
why it is a nonquestion. Who said that our theories will be correct?  

The best practical way to suspend someone is to freeze them slowly and over
a longish period. In real suspensions, they are frozen first to below 0 C,
and then an automatic system ramps them down slowly over several days. (At
one time that system wasn't automatic, some real person had to watch over
the patients; but Hugh Hixon and Keith Henson (I believe) successfully
worked out a way to automate that phase).

One of the major real questions we are trying to deal with now has 2 "phases":
first, we want better solutions for taking someone down to freezing level.
Such solutions must protect patients against the effects of ischemia, for 
instance. Second, we want better solutions for long term storage. Right now,
in my book, the best work on this second phase is done by Greg Fahy, who is 
a professional (PhD) cryobiologist and has been developing means to vitrify
kidneys rather than freeze them. Since virtually all the damage due to freezing

comes from crystallization of the ice-solution mixture, finding a way to make 
itturn into a glass would cut that damage WAY down.

In terms of whether or not such techniques will preserve our memory, I will
say this: the current ideas about memory held by most neuroscientists would 
say that our memories are encoded at the level of a cells, not in specific
molecules. (A light microscope of high magnification could verify that 
memories were or were not present). To recover memories from a brain damaged
by freezing, ischemia, and all the other things that would damage brains will
very likely take examination on a molecular rather than a cellular level.

There seems to be someone on Cryonet who would be happy to be revived with
no memories of his previous life at all. That can be easily done right now,
though most of us want much more than that to be preserved. Still, each to
their own.

			Best and long long life,

				Thomas Donaldson


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