X-Message-Number: 1998
From: whscad1!kqb (Kevin Q Brown +1 201 386 7344)
Subject: CRYONICS Ettinger replies concerning -136 C storage

Robert Ettinger sent to me his replies to the Feb. 28 - March 12
CryoNet postings concerning approx. -136 C storage and I have
appended them below.
				  Kevin Q. Brown
				  
				  
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			  CRYONICS INSTITUTE
		24443 Roanoke, Oak Park, Michigan 48237
	      Telephone (313) 548-9549 or (313) 547-2316

March 15, 1993

> Subject: Not-so-cold storage

From: Robert Ettinger

To: Correspondents       


Kevin Brown has kindly sent me a summary of CryoNet comments, Feb.
28 - March 12.  Let me Let me try to summarize part of this summary
and comment.  (No offense to those not mentioned; I am citing /
commenting mainly where I have a further comment that might be
useful.)

Brian Wowk reiterated the concern of Steve Harris and others about
convection in the flotation approach.  I note again that convection
will occur, and also that stratum temperature (aside from
convection) depends not only on distance above the liquid nitrogen
but also on the total height of the column; but appropriate use of
conducting and insulating sheaths may damp the effects
sufficiently.  We won't know until we try it, which Cryonics
Institute intends to do.  (Mr.  Wowk has also mentioned the use of
a conductive sheath to suppress temperature variations over the
patient's surface.)

Brian Wowk comments on my observation that, since people have
recovered fully after drowning in cold water with more than 45
minutes immersion, this tends to prove (within the limits of the
examples) that -- if someone is cooled quickly after clinical
death -- any other treatment can have only marginal importance.  (1)
He thinks, in the drowing cases, the heart may have kept beating
a considerable time, and that blood oxygen can keep things going
(most systems functioning?) for ten minutes or more without
breathing.  (2) He thinks cooling, after drowning in cold water,
would be more than the "moderate" amount I mentioned.  (3) He
concludes that, unless a cryonics patient gets prompt and effective
cooling, and cardiopulmonary support, he will be in much worse
shape after 45 minutes than a cold-water drowning victim.

My comment: (1) Even if true, the prompt cooling is still the main
consideration.  (And, contrary to Mr.  Wowk's comment, all cryonics
organizations do provide prompt cooling and cardiopulmonary
support, when feasible -- not necessarily with equal efficiency.)
(2) I said "moderate" cooling in the drowning cases as a
conservative estimate that tended to reduce the power of my
argument.  lf there was more cooling, all the better for the
argument -- more evidence that the degree and rate of cooling are
primary factors, as compared with medication.  (3) Agreed.  But if
prompt cooling is the main factor, then, for patients at a
distance, it is much more important to try to get local (mortuary
or other) people to provide it than to rely on traveling teams from
a cryonics organization; and in such cases the matter of
cardiopulmonary support may be secondary, and that of medications
tertiary at most.

Rich Schroeppel suggests that storage at -50 C might be adequate,
based on assumptions about enzymatic and other activity.  (One of
his assumptions is refuted by Brian Wowk.) Comment: As far as I
know, no really definitive work has been done on long term damage
in these temperature ranges.  We know that some tissues suffer
considerable long term -- even relatively short term -- damage in
dry ice, but whether deterioration continues indefinitely or is
self-limiting isn't clear to me.

Several people have been talking about room-sized storage with
conventional (non-vacuum) insulation.  Brian Wowk offers
calculations involving an "optimum" 2 meters of foam insulation,
with a room 5m x 5m x 3m.  However, unless I have misread him
somehow, he has overlooked a crucial point.  He says the thermal
conductivity of good foam insulation is 0.02 watt/m/degC; this is
not true.  The coefficient (0.02 watt/m/degC in this case) is not a
constant, but varies with distance.  The relation is linear
(Newton's law of heat transfer) only for fairly thin walls.  For
thick walls, or at least walls that are thick relative to the
overall dimensions, the temperature gradient is much steeper near
the inside than near the outside, which means that increasing
thickness rapidly loses effectiveness.  I haven't done the
calculation for Mr.  Wowk's case, but the boiloff will be much
larger than he says.

Charles Platt thinks nanotech could repair big fractures more
easily than cellular damage (which also occurs), hence there is
little point to the higher temperature storage.  But others -- some
very well informed -- think the opposite, that cellular damage
would be easier to fix, because the connections could be more
easily inferred.

Ralph Merkle seems to agree with me that nanotech is likely to be
both necessary and sufficient to repair damage caused by current
procedures, and also by the not-so-cold storage, hence the latter
is likely to be of marginal importance at best.  But because
opinions differ, and we want to make all feasible options
available, CI still plans to investigate further.

Mike Darwin says the typical cryonics patient is not comparable to
a cold water drowning victim, and that his studies show the former
suffers serious injury during ischemia and reperfusion, and
that "...some of this injury results in immediate and serious
destruction of ultrastructure.  Other injury is secondary to loss
of capillary integrity, leukocyte plugging of capillaries, and
other problems which compromise subsequent cryoprotective
perfusion." Comment: The first part of that quotation does not seem
convincing, in light of the extensive experience with recovery or
partial recovery of animals and tissues under very adverse
circumstances.  As to the second part, we seem to get pretty good
cryoprotectant uptake with relatively simple procedures.

Mike Darwin offers to provide uniformly glycerolized animals --
dogs or pigs -- in dry ice, for Cryonics Institute to test further
cooling and not-so-cold storage.  We thank him and his associates
for this, but we will not any time soon be prepared to handle
specimens that large; but we could use the heads.  Our first step
is to prepare the cryostat; we expect to have the HSSV-1
reconfigured in a week or two.  We will then measure temperatures
at various heights and radii above the liquid nitrogen, with
various depths of liquid; and we will test the efficacy of
temperature change damping using sheaths of conductors and
insulators.  If these results are encouraging, we will prepare a
flotation device and make further tests.  After that we may be
ready for further work, consisting of or leading up to the kinds of
experiments Mike suggests.  At that point, if everyone is in
agreement, we will undertake a cooperative effort; or if there
isn't agreement, we will do whatever we judge to be warranted.

A couple of people agreed that glycerine concentration can vary
over parts of the body, and therefore the ideal storage temperature
could vary from point to point, but they said we need only worry
about the brain.  Nobody connected with ny suggestion that
cryoprotectant concentration will probably also vary from region to
region, tissue to tissue, of the brain itself.  I still don't know
how much of this kind of variation actually occurs; in fact, I
don't even know what methods Alcor or Cryovita uses to assess local
concentrations.

Nobody seems to have commented on my letter of Feb. 21 on the idea
of radial strata without a gas region, so I assume no one has found
any fatal defect.  When CI buys and moves into a new building, we
will work on this too, if the whole not-so-cold idea still seems
worth pursuing.

On the topic of different kinds of insulation, I remind people that
one of these days someone is going to renew the production of rigid
open-cell foam, which will allow moderate- vacuum insulation with
rectangular geometry without internal bracing -- a big improvement
over both the MVE type units and ours.  Also, there is already
commercially available, or according to reports very soon will be,
mass-produced vacuum insulation modules (intended for kitchen
refrigerators as a substantial advance over the present foam).
I've misplaced the reference, but it will certainly surface again
soon.
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