From: Anders Sandberg (asa@nada.kth.se)
Date: Sun Sep 14 1997 - 03:56:09 MDT
Geoff Smith <geoffs@unixg.ubc.ca> writes:
> On 12 Sep 1997, Anders Sandberg wrote:
>
> > Actually, this is what occurs when the body is frozen. Ice forms
> > *between* the cells, not inside them, and they are largely dehydrated.
> > Causes damage too, unfortunately.
>
> Excuse my obvious ignorance of this subject. How exactly does this
> happen? What causes the transport of water out of the cytoplasm and
> through the cell membrane when the cell is being frozen? I assume if
> freezing is done quickly, the resulting dehydration of the cell is a rapid
> process. Wouldn't the sudden increase in volume of intersitial fluid
> damage the cells before the water even froze?
Actually, there is no need to excuse one's ignorance unless one
should have paid attention. A willingness to learn and an awareness
of what one doesn't know is only healthy!
Ice is pure water (other chemicals don't fit into the crystal lattice),
so when interstitial fluid freezes it will become more concentrated
since the other chemicals don't get frozen. This will lead to an
osmotic imbalance between the cells and the surroundings, which will
cause water to leave the cells. Since concentrated solutions also
freeze at lower temperatures than dilute solutions the cells will
not freeze until they reach the vitrification temperature, where
the water molecules simply form a glass (not a crystal); if we
could somehow vitrify tissues, then cryonics would have much better
chances.
-- ----------------------------------------------------------------------- Anders Sandberg Towards Ascension! asa@nada.kth.se http://www.nada.kth.se/~asa/ GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y
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