X-Message-Number: 2534
Date: 11 Jan 94 05:59:03 EST
From: Mike Darwin <>
Subject: SCI.CRYONICS Response to Ben Best

Some Further Thoughts on Ben Best's Critique:

I realized AFTER I posted it that there were a number of points I left
unanswered in my response to Ben Best.  I'll keep it brief.

1) I have never denied that sugars may be important as membrane
stabilizers both in cryopreservation and in freeze-drying.  Specifically,
this was one of the major reasons sucrose was used to replace mannitol in
the Alcor perfusate.  While it was understood that sucrose would not
penetrate the cell, it was thought (and there was evidence to support
this) that it would help by stabilizing the exposed cell membrane. This
may be still be a valid rationale and I remain acutely interested in other
sugars, although I have abandoned sucrose for this purpose because of its
nephrotoxcicity.  The reason sucrose was chosen in the first place was due
to the fact that it is many times cheaper than trehalose, which is
actually a better sugar for the purpose.  Tom Anchordougy (a membrane
cryobiologist) suggested sucrose as an alternative since it was nearly as
effective as trehalose in his models.  I go over this here to make the
point that I am not insenstive to the use of sugars and I believe that
this was even discussed in CRYONICS at the time the change was made.

2) The above notwithstanding, the use of sucrose as Skrecky proposes it
was not PRIMARILY as a membrane stabilizer but as a room temperature
vitrification agent.

3) I did not slam or attack Skrecky: I attacked his ideas, his poor
science, and his method of presentation.  There is large difference here. 
I deliberately kept personalities out of it: something which Ben did not
do in his response.

4) I did not say that mammalian cells are completely impermentant to
glycerol and I'm sorry if that was the implication from my writing. 
Clearly we get some glycerol into the intracellular space or glycerol
would not be an effective cryoprotectant since it is a colligative agent:
one which works by minimizing the amount of ice formed. (Also, if we did
not, we would almost completely dry out our patients, something which
does not appear to be happening.)  However, it is fair to say that we
are, in addition to glycerolizing our patients' cells, also dehydrating
them.  This is probably undesirable and it would (in my guesstimation)
probably be better if we could find an agent which is a good glass
former, is less toxic, and more penetrative.  Alas, the search for THAT
philosopher's stone of brain cryopreservation goes on without much
success so far.  However, there HAS been success with other organs and it
is now possible to load and unload mammalian kidneys with a 1-atmosphere
vitrifiable concentration of agents, cool them to -20C, and have them
recover to support the animal as the sole kidney (G. Fahy, personal

This is hopeful, since if it can be done to kidneys it may well be
possible to do it to brains as well.

4) While I share Ben's concerns about organizational stability, I also
think there are other issues to address.  At this point it can only be a
matter of opinion, but it is my bet that successful cryopreservation
techniques for multiple organs (kidneys and livers seem do-able NOW) and
for the brain would do much to move cryonics into the medical mainstream. 
It is also my strong suspicion that any technique that works for the brain
may well be adapted to work for most or all of the other organs as well. 
This would bring us to the point of true suspended animation -- even if we
had to transplant a few visceral organs that didn't make it.  Being able
to successfully cryopreserve CNS, PNS, skeletal muscle, bone and skin are
the major requirements.  Anything else is gravy.  I think that it is
within the realm of possibility that that kind of technology is within our
grasp.  And that WILL revolutionize things, and it WILL change medicine
and our society as a whole.

The point is, there is only one way to find out.  I prefer to put most of
my energy into that approach.  I have no objection to others working on
techniques for high temperature storage.  In fact, I would encourage it
and I have many ideas about simple, and relatively inexpensive projects
which they can do.  In fact, I am even willing to HELP.

However, people must be willing to DO this research and to PAY for it.  It
is a given that everyone wants to SEE research done.  But are they willing
to do it and/or pay for it?  That is quite another matter and it is not
resolved by sitting in a library, with or without a degree.

And do not say that this kind of research requires costly facilities or is
impossible to carry out...  Anyone who has gone to a high school science
fair will understand what amazing work can be achieved with very little. 
This kind of work is ideally suited to this approach.

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