X-Message-Number: 27484
From: "Brian Wowk" <>
Subject: Reply to David Verbeke re mammal experiments
Date: Sun, 15 Jan 2006 23:19:45 -0800

    There have been several privately published experiments (and many more 
unpublished ones) in which large mammals have been cryopreserved using 
cryonics methods, or in which small mammals have been cryopreserved under 
conditions replicating human cryonics.  In these days of the Web, I don't 
know why they seem to be unknown.  Typing "brain cryopreservation" on Google 
immediately takes one to the most comprehensive and well-known cryonics 
replication experiment in large dogs called

"EFFECT OF HUMAN CRYOPRESERVATION PROTOCOL ON THE ULTRASTRUCTURE OF THE 
CANINE BRAIN"

http://www.alcor.org/Library/html/braincryopreservation1.html

performed by Mike Darwin and collaborators at BioPreservation, Inc. in 1995. 
The Alcor online Library also contains the slide presentation

http://www.alcor.org/Library/html/cambridge.html

and full-text Annals of the New York Academy of Sciences paper

http://www.alcor.org/Library/html/annals.html

that document the effects of cryopreservation using Alcor's current 
vitrification solution, M22.  Although these latter studies were performed 
in rabbits, I can testify that the rabbit experiments have been replicated 
at human brain core cooling rates (taking approximately 5 hours to reach the 
glass transition temperature), and the results are the same.  There were 
also similar mammalian cryonics replication experiments presented at Lake 
Tahoe Life Extension Conferences back in the 1980s using the technology of 
that era, although those are ancient history now.

    Mr. Verbeke asked for references to experiments at liquid nitrogen 
temperature, "not -90 C or -130 C".  But this reflects a misunderstanding of 
cryobiology that perhaps should be clarified within these papers or on 
cryonics websites.  -90C is the glass transition temperature of 
freeze-concentrated glycerol solutions, and -124 C is the glass transition 
temperature of M22 vitrification solution.  There will be NO DIFFERENCE in 
the microscopic state of tissue cooled to the glass transition temperature 
vs. liquid nitrogen temperature, or absolute zero for that matter.  The only 
change that occurs in tissue with further cooling below the glass transition 
temperature is macroscopic thermal stress fracturing.  This is a well-known 
fact of cryobiological physics.  Questioning whether tissue cooled to -196C 
will microscropically look the same as tissue cooled to -135 degC is a bit 
like questioning whether a space probe travelling faster than solar escape 
velocity beyond Pluto really will escape from the Sun.  We don't have to do 
the experiment to know the answer.  The laws of physics are what they are.

    I believe CI has done similar experiments with its older freezing 
protocols on sheep brains.  Perhaps someday those articles and micrographs 
can also be put on the Web for posterity.

    I find it deeply disturbing that many cryonicists don't seem to be aware 
of the theory or experiments that underpin the field of cryonics and the way 
it is practiced.  Just last week I had to correct an otherwise highly 
intelligent and thoughtful Imminst member that seriously proposed straight 
freezing (freezing without cryoprotectant) might be better than using "toxic 
cryoprotectants".  Practicing cryonics without knowledge of the effects of 
cryoprotectants or the experiments that show them is a bit like practicing 
medicine without the germ theory of disease.

---Brian Wowk 



-- 
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.1.371 / Virus Database: 267.14.18/230 - Release Date: 1/14/2006

Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=27484