X-Message-Number: 560
Subject: Cryonics news from Trans-Time
From: spectrx! (Edgar W. Swank)
Date: Sun, 01 Dec 91 12:29:02 PST

     [Reprinted from The Immortalist - October, 1991]
 
                      THE TRANS TIMES
 
                      Research Update
 
                   by Hal Sternberg, Ph.D.
 
TRANS TIME and BioTime continue to find the small animal model
[reviving hamsters following perfusion with cryoprotective solutions]
very useful in improving cryonics suspension protocols.
 
We have observed damage to the microcirculation, particularly
noticeable in the brain, upon thawing and reperfusing blood into
previously cryoprotected frozen hamsters.  We have found that this
brain damage can be prevented by using various cryoprotective
solutions of relatively high molarity (about 3M and above), which
cause excessive dehydration (observed visually).  Solutions which lead
to edema increase this damage and limit reperfusion to the brain.
 
The cryoprotective solutions used for cryonic suspension by TRANS TIME
have been tested in hamsters and lead to moderate dehydration of the
brain and other tissues.  Dehydration protects against freeze-damage
and may be a positive step toward reversible cryonic suspension, as
turtles which are freeze-tolerant undergo substantial dehydration
before freezing.
 
Our general knowledge of cryoprotection/freezing/thawing technology is
improving.  At the recent April conference of FASEB (Federation of
American Societies for Experimental Biology) we reported a
reproducible method for restoring strong rhythmic EKG signals along
with heart beats from cryoprotected/frozen/thawed/reperfused hamsters.
These hamsters were frozen overnight to between -1.6 to -2.2 deg.  C.
Even more recently we have restored heart beats and EKG signals from
hamsters frozen to as low as -3.5 deg.  C overnight.  The restoration
of this physiological function, which involves the coordinated
participation of millions of cardiac cells (myocytes, nodal cells and
Purkinje cells) indicates we are learning how to reduce freezing
damage, a major obstacle of reversible cryonic suspension.

--
 (Edgar W. Swank)
SPECTROX SYSTEMS (408)252-1005
Silicon Valley, Ca

Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=560