X-Message-Number: 1937
Date: Thu, 11 Mar 93 01:05:26 CST
From: Brian Wowk <>
Subject: CRYONICS Cold Storage

Richard Schroeppel:
 
> Problem:  Biological tissues cooled much below the glass transition
> temperature crack, making reconstruction difficult, and possibly
> losing important ultra-structural information.
 
> Solution:  Only freeze the tissue cold enough to inhibit bacterial
> growth, and slow down enzymatic degradation.  Micro-pockets of water
> will remain in the liquid state, but if they are small enough, we
> don't care.  A few enzymes will do a small amount of damage, but the
> total damage is much smaller than pervasive cracking.  Any enzyme
> promoting an endothermic reaction will stop immediately due to lack
> of ATP.  If the tissue is mostly ice, then no significant diffusion
> will take place, so all enzymes should run out of reactants pretty
> quickly.  If a few enzymes are responsible for damage, then we can
> look for inhibitors, and administer them during cool-down.
> If the bulk structure of the tissue is solid, and enough of the cell
> walls survive that synapse positions can be determined, then there's
> a possibility of a nanotech reconstruction.  Perhaps -50C would be a
> reasonable temperature.
 
        Proteolytic enzymes do not need ATP to do their dirty work.  
Ambient thermal energy serves just fine.  Why not store at or near TG
(-130'C)?  That way we can have our cake and eat it too.
 
                                                --- Brian Wowk

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