X-Message-Number: 31781
Date: Mon, 29 Jun 2009 13:33:50 -0700
Subject: Possible experiment
From: Brian Wowk <>

> Message #31774
> From: "Kennita (Go Cryo!)" <>
>
> How much would it cost to washout a mouse, to perfuse it with our
> latest vitrification solution, to replace the blood, and to attempt to
> revive the mouse? How long would it take? Who should perform the
> experiment? Given that a similar experiment was successfully completed
> on a dog years ago (with the added step of lowering the temperature to
> near freezing) using the more primitive cryoprotectant, what would you
> say the chances are of ending up with a live, functional mouse?

      Experiments replacing blood in dogs, cooling them to near 0 degC
for several hours, and subsequently recovering them have indeed been
done in cryonics

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

and in mainstream medical research since the mid 20th century
(although I'm not aware of any published research doing it for as long
a time period as in the above CryoVita/Alcor experiments).  These
experiments were done by cryonicists because blood substitution and
cooling to near 0 degC is the first step of a human cryopreservation
protocol, so survival of this step is necessary if cryopreservation is
ever to be demonstrably reversible.  Now that this has been achieved,
demonstrating survival of animals after adding cryoprotectant
chemicals (vitrification solution) to the blood substitution solution
near 0 degC would seem to be the next logical step.

       In fact, the current vitrification solution used by Alcor (M22)
is a solution that was developed at 21CM by loading and unloading an
isolated vital organ (kidney) with solution at cold temperature with
subsequent survival of the organ.  If it can be done with an organ,
why not a whole animal?  It is possible that a whole animal could
survive a short time period of cold perfusion with a vitrification
solution, or diluted vitrification solution.  However I expect that
the compromise in perfusion time and/or concentration necessary for
survival of all organs and tissues in parallel would not be consistent
with sufficient cryoprotection to survive actual vitrification.  I
personally would feel more comfortable attempting such whole animal
experiments once there was more success cryopreserving isolated
organs, especially the brain, heart, and other vital organs.  As a
practical matter, no cryonics organization currently has the resources
or expertise required to perform whole animal hypothermic perfusion
survival experiments.  In hindsight, the combination of people and
circumstances that permitted such experiments in the 1980s was rather
unique.

       In May, 2007, 21CM disclosed a research initiative to begin
studying cryoprotection of multiple organs in parallel, essentially by
perfusing entire animals with cryoprotectant.  After having moved to a
larger facility to accommodate the research, acquiring necessary
staff, and constructing a highly sophisticated cryoprotectant
perfusion machine, this initiative is presently at the stage of
measuring cryoprotectant concentrations achieved in various organs and
tissues during whole body perfusion.  Survival experiments are
anticipated eventually, but not for several years at least.  It's
important that such experiments be built upon sufficient foundation to
maximize scientific value, rather than staged for publicity and
possibly misunderstood in terms of context and significance.

---Brian Wowk

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