X-Message-Number: 5023
Date: 20 Oct 95 20:09:34 EDT
From: "Steven B. Harris" <>
Subject: CRYONICS: Comments to Ettinger (pt. II)

<Continued Comments to Ettinger and Clark, Pt 2>

Dr. Ettinger continues:

    >>Second, those who are too close to the forest sometimes see
only a few trees, even forgetting what they saw yesterday. For
example, many experiments have established the extreme freeze
hardiness of DNA and many kinds of individual cells. Some kinds
of sperm show a good survival count after straight freezing 
down to liquid nitrogen temperature and even liquid helium
temperature. Now, is it possible that some kinds of cells, and
all or most of their organelles, are very freeze hardy, yet some
other kinds are extremely fragile, disappearing with scarcely a
trace? Possible, perhaps--but much more likely the differences
are only of moderate degree, and the "destroyed" cells or 
tissues are only damaged.<<

    Comment: I'm afraid I cannot follow this reasoning.  Single
cells are here being compared with the freeze-tolerance of
tissues, in which individual cells are subjected to unusual
forces due to the macroscopic effects of intracellular-space
freezing, and also to the effects of ischemia due to loss of
perfusion.  Under these conditions, cells DO blow up and visually
disappear.  No amount of argument that they must still be around
in spirit (the reason Dr. Ettinger is getting accused of Platon-
ism in this argument) will suffice to convince.  The parallel
argument is that some cells (sperm) are freeze tolerant, and so
therefore if sperm are mishandled so that they all osmotically
lyse during freezing, that it is "more likely" that they are only
damaged to a moderate degree, instead of utterly destroyed.  I
hope they are not, but I do not dare to assume they are not. 
Cryonics is forced optimism, but I hate to see it degenerate into
general optimism about things that can be changed.

   >> Of course we need to find out, not guess--but we do 
NOT need to assume the worst while we are trying to find out. <<

    No, we can assume the best, and meanwhile do nothing 
clinically (that is, in our actually care of cryonics patients). 
Which is the tack which Dr. Ettinger has taken, I suppose.  But
once you start down this road, why bother to use cryoprotectant
at all in people?  The differences between using it and not using
it are all the same sort of thing which Dr. Ettinger is talking
about, as are the differences between 30 minutes of ischemia and
12 hours' worth.  Here is exactly the problem.  Too much optomism
leads to a "deliver them to my door cold when you feel like it"
attitude.  Why not?
 
   >>Audrey Smith's hamsters survived after about half the water
in the brain was frozen, and seemed to show normal behavior
afterward, even though there were no actual tests of retention of
learned behavior. Of course, it is conceivable that the other
half of the water--the half that was not frozen in the hamsters--
-was the important and devastating half, and that after this 
cut-off point some cataclysmic event(s) occur(s); but it isn't
likely.<<

   I beg to differ-- it is more than likely, given Suda's brain
work.  It is possible to calculate that the temperature (-20 C)
to which Suda would take brains and still get a reasonably normal
EEG after even many years, was that at which half the brain water
was still unfrozen.  But Suda found that lowering temperatures
below that destroyed his EEGs immediately.  Obviously, a great
deal of further damage was being done in freezing that last bit
of water.  The same, of course, is true of hamsters.  Take them
to -10 C and they don't revive.   Their hearts don't even start. 

  >> More likely, completion of the freezing would do enough
damage to be fatal by the usual criteria, but would still be far
short of annihilation.<<

   No way to infer this at all.

  >> Same remarks: we need to know, not guess--but meanwhile we
needn't assume the worst. <<

   And again my same remarks: it is silly in medicine to shut
one's eyes and assume the best, unless one is trapped by 
circumstance into having no choice.
 
    >>Hossmann's and Sato's cat survived and did not show unusual
behavior after close to an hour of total brain ischemia. Later
examination reportedly showed brain damage--perhaps related to
some kinds of memory, a disturbing thought--but clearly the cat
LIVED, which is the outstanding result.<<

    As has been pointed out, being alive without one's memories
is not much better than being cloned.  Furthermore, Sato's cat
tells us that things aren't totally destroyed in a cat after an
hour, but really does not tell us much about a human.
 
   >>Several people have revived completely or nearly so--includ-
ing memory--after drowning in cold water, sometimes being
immersed for an estimated hour or near that.<<

    Only children.  They are special in getting rapid cooling to
a well-exposed brain, with lung-heart-brain circulation 
continuing long after immersion (at least 15 minutes), due to the
diving reflex (it takes hanged men at least that long for cardiac
arrest, and many cooled submersed children who do not inhale
water are surely slower).  Icewater drowned children are NOT a
good model for the adult cryonics patient, except for those
cryonics patients who are immediately immersed in ice and
subjected to CPR after clinical death, with no more than a few
minutes delay.

   >>Ischemic/anoxic time must have been close to the time under
water. <<

    I don't agree.  Since ischemic duration for the brain
increases by a factor of 3.5 for every 10 C of cooling, actually
body-temp ischemic time for these children is remarkable short
with respect to many a cryonics patient, even before 
cryoprotectant perfusion begins.  The worst thing is that if you
look at the broad ischemic boundary beyond which cellular damage
becomes gross as the pathology level (about 30-45 minutes time at
normal body temp, or equivalent time, adjusted for body temp and
metabolism) you find that the average ice-water drowned child is
well on this side of that, and the average cryonics patient,
unless subjected to on-the-spot ice water immersion and CPR at
clinical death, is well on the OTHER side of it.  This does not
seen to bother Dr. Ettinger.  It bothers me.

   >>These were generally young, healthy people, true, but they
received no prior medication or treatment of any kind, yet
survived and retained their memories.<<

    Yes, but see above.

   >> A determined pessimist can find reasons to discount this,
but he'll have to work at it. <<

     On the contrary, the only work I have to do is to explain to
people who have not tried to revive animals from both warm
ischemia and ice-water perfusion, how exponentially fast the
damage rises after the "15 minute at body temp" mark.  This is
reality, albeit not something in the range of normal human
experience.  Linear extrapolations, and extrapolations which
don't take into account the metabolic protection effect of cold
on the brain, simply do not have any basis in reality.  ALL of
what we know says that ischemic damage alone, here (forgetting
all cryodamage) takes many cryonicists into the zone in which we
have no idea about whether or not memories survive, from animal
data or even in a theoretic sense.  It is way past the ischemic
damage zone from which person, or any dog, has yet been revived
(if you count that single brain damaged cat you get farther into
the zone, but most cryonicists still go way beyond even this, and
do so even before cryoprotectant perfusion).  I see no reason for
optimism about putting people into this injury zone, when it can
be avoided.  

   As for the damage done in *freezing* with today's methods
(cryo-injury), it is the same kind of thing, WITH THE DIFFERENCE
that it cannot be avoided by today's techniques.  Thus, here we
are forced to be optomistic, if we want to try cryonics.  This is
no reason not to work as hard as possible to invent ways to stop
it.

   >> Our cryostasis patients are usually old and sick, but 
often they receive much quicker cooling than these drowning
patients--cooling with ice or ice-cold water or other fluid and
with forced circulation to help the cooling and a bit later with
internal cooling....<<

   Eh, WHOSE patients are you talking about??  So far as I know,
C.I. has presented NO evidence (cooling curve, case report) that
even a single one of C.I.'s patients, even before cryoprotectant
perfusion, was subjected to within even an order of magnitude of
the brain "normal body temp equivalent" ischemic time of the
average immersed child, or the average successfully resuscitated
dog.  

   >>In general, the cryothermic damage is by far worse than the
hypothermic or even (except in the worst cases) the 
normothermic.<<

    That's very hard to say, for it is hard to separate ischemic
time from cryo-injury, since ischemic time prevents perfusion of
cryoprotectants.   Much also depends on how long ischemia has
been sustained.  Has anybody looked at the unfrozen brains of
animals held at ice temp for 1 or 2 days (the fate of many a
cryonicist, even signed up), vs. a very carefully perfused and
frozen animal with no ischemic time at all (or less than 5
minutes worth, body temp equivalent?).  

   >>It is ironic that Mike Darwin and some others take ALMOST
the same position as those physicians and scientists who refuse
to admit the admissibility of unproven procedures even when there
is no other hope, even when the patient is already clinically and
legally dead--who refuse to place any burden whatsoever on the
future. <<

    But there *is* other hope for reducing ischemic time.  It is
called "remote standby with CPR and ice bath."  There is a
DIFFERENCE between unfounded optimism when you're out of options,
and unfounded optimism when you're not.   Cryonics is about hope
when you've done the best you can, it's not about using hope as
an excuse to keep you from improving your technique.



                                  Steve Harris


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