X-Message-Number: 8974
From: Thomas Donaldson <>
Subject: Re: CryoNet #8965 - #8966
Date: Tue, 6 Jan 1998 21:48:34 -0800 (PST)

To Randy Smith:

I know Biotime and its researchers quite well. The news article, whether by
deliberate action of someone involved or not, has confused several issues.
Hextend is a good solution for taking medical patients down to low temperatures
just above 0 C. They have tested Hextend on baboons.

However, the idea of taking baboons down to liquid nitrogen temperatures, or
any temperatures low enough for storage for more than 12 hours, is presently
a dream only. At a Conference just in December 1997, Paul Segal described
experiments attempting to use Hextend and cryoprotectants to take guinea
pigs down low enough to freeze. They were not able to revive the guinea pigs
to a healthy state: all came back with widespread brain, heart, and organ
damage, and did not survive for very long.

I do not wish to denigrate Hextend. It may prove to be very useful for 
medical purposes, greatly extending the time in which an operation may be 
done on the brain or the heart. Taking the temperature down to the required
level WITHOUT removing the blood has proven to be fatal too often --- and
that required level is still above freezing. Hextend may even help in
reviving people after the so-called "five minute limit": other research,
not done by Biotime, suggests that lowering the temperature has lots of
unexpected favorable effects and looks like it really will allow revivals
to full consciousness if circulation and breathing have stopped at normal
temperature for as long as 15 minutes. But Biotime is still nowhere near
suspended animation as seen in science fiction or cryonics.

			Best and long long life,

				Thomas Donaldson

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