X-Message-Number: 11790
Date: Thu, 20 May 1999 11:16:17 -0700 (PDT)
From: Doug Skrecky <>
Subject: freeze-drying

In Message #11780  wrote:

>The main disadvantage--of either freeze-drying or chemical fixation, or a 
combination--of course is just the fact that viability (as currently observed 
or measured) is virtually nil at the level of mammalian tissues, in the 
context of current capabilities. This may be more of a psychological problem 
than a scientific problem, in the context of future technology. Logically, a 
sufficient degree of preservation of structure is all that is necessary, with 
preservation of function pretty much irrelevant--but that is a hard sell 
indeed, even to most committed cryonicists.
<
  Liquid-drying may be a way around this. Organisms that undergo
anhydrobiosis use a variant of this method to survive complete
desiccation. Experiments with freeze-intolerant bacteria have found that
this can preserve viability, when adequate protection against free radical
damage is provided. Human application of this would need some basic
research done first. Freeze-drying is always going to be at least as
damaging as freezing. Liquid-drying avoids this.

>Another possible disadvantage might be cost of preparation. Freeze-drying 
something as large as a human, by any currently used methods, is a very slow 
process, and therefore an expensive one. We have some ideas to offset this, 
but so far we cannot see our way to giving this project a high priority. A 
higher level of research donations could change this.
<
  I suggest that the most cost effective start for any research program
into any type of drying preservation would be to complete a search of past
experiments in this field. Only after reading and analysing all of the
existing relevant data on the topic could a practical, affordible
experimental program be devised.

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