X-Message-Number: 7731
From: Brian Wowk <>
Date: Sun, 23 Feb 1997 02:05:31 -0600 (CST)
Subject: Freezing damage

Bob Ettinger writes:
>Brian Wowk's #7715, including discussion of ice damage, is a bit misleading
>in some respects. "...ice squeezes vital ions and proteins out of the tissue,
>forcing them into shrinking pockets of residual unfrozen water. Even the
>fabric of cells themselves is crushed into these tiny spaces among the ice
>Actually, the expansion of water as it freezes is only roughly 10%; hence, 
>on average, tissues are NOT "squeezed into tiny spaces," although some 
>may be. 
        While I respect you, Bob, and acknowledge we wouldn't even be
here discussing these things if it wasn't for you, I have to say that
the above statement indicates a very serious misunderstanding of the
nature of cryoinjury.  The belief that expansion of water during
freezing causes cryoinjury is a popular misconception.  Fundamentally,
it is not the expansion of ice, but the EXISTENCE of ice that damages
tissue during freezing.
        Freezing is a process of phase separation and purification.
If X percent of water in tissue freezes during slow cooling, then 
*by definition* solute molecules and cell structures will be compressed 
into the remaining 100-X percent of unfrozen water.  Ice crystals consist 
of pure water, and cannot accomodate biological machinery inside them.  
That's why electron micrographs of frozen brains are full of "holes"--
open spaces where ice crystals displaced normal structures. 
        In fact, the story with freezing is even worse than this.
Most of the solutes that become "freeze concentrated" (as Doug
Skrecky recently put it) in the intercellular space are impermeant 
species.  Thus not only are cells mechanically forced into spaces
between ice crystals, but they experience large osmotic dehydration
within those spaces.
        Biophysics aside, the most potent illustration of the damaging
effect of freezing is the empirical fact that most organs do not survive
conversion of more than 50% of their water to ice.
>For a more balanced and optimistic discussion of ice damage (and 
>limitations thereof), see e.g. Greg Fahy's sworn declaration in the 
>Dora Kent case (Case No. 191277, Superior Court, County of Riverside, 
>California, Appendix of Declarations, dated Feb. 1, 1988). (The 
>Immortalist Society has reprints available.)
        Certainly with a hyperadvanced nanotechnology, even patients
frozen under very bad conditions could be revived.  (This leaves us
with the debate of how much memory they will be revived with, but
let's not discuss that right now.)  The point is that freezing, as it 
occurs in cryonics today, is a very serious injury that will require 
advanced nanotech for repair.  If we can get rid of freezing injury,
that will bring a major reduction in the technology level required
for revival, a major increase in the credibility of cryonics, and
a major step in the direction of true suspended animation.
Brian Wowk          CryoCare Foundation               1-800-TOP-CARE
President           Human Cryopreservation Services   

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