X-Message-Number: 33131
Date: Fri, 24 Dec 2010 13:09:17 -0800 (PST)
Subject: Long dissertation from Mike Darwin




I found part 3 of Mike Darwin's analysis to be particularly interesting. The
image provided of straight frozen brain tissue does indeed resemble a
tissue homogenate, and is dramatically poorer than that of fixed brain
tissue. Yet currently many corpses being stored at cryonics providers were
straight frozen.

Snip from Part 3>
"For my own benefit in charting progress in this area I developed a scoring
system based on ultrastructure following cryopreservation, rewarming and
fixation. I won?t pretend to argue its merits except as an approximate
yardstick for measuring progress.
At left is brain tissue from a healthy animal perfused with fixative while
under anesthesia and with no ischemia (e.g., beating heart). The fine
architecture of the tissue is beautifully displayed and at 9K magnification
it is possible to see intracellular organelles, such as the nuclei and
mitochondria, as well the myelin sheathing, cell membranes and axoplasm.
At right is tissue taken from the same anatomical area of the cerebral
cortex following straight freezing and rewarming. Cell membranes are no
longer visible and the field of view appears more like a tissue homogenate
than a section of brain tissue. I assign this level of injury a score of 15,
as opposed to a score of 100 for control brain tissue. It is not possible to
score higher than 75, regardless of the quality of ultrastructural
preservation, in the absence of viability; viability therefore counts for 25
It is possible to do the same kind of scoring with respect to the
pre-cryopreservation parts of cryonics procedures, as well. A patient with
no peri- or post-arrest ischemia who was provided with immediate and
effective CPS followed by CPA perfusion within the window of demonstrated
viability (i.e., 5 hours of asanguineous perfusion at 5oC) would thus get a
score of 100 in terms of Clinical Services Delivery. In other words, that
patient would have received the best technologically available
pre-cryoprotective care it is currently possible to deliver.
Since all cryonics patients currently must be pronounced legally dead before
the procedure can begin, no patient can score 100. I have arbitrarily
decided that each minute of normothermic ischemia up to 5 minutes will count
for the loss of 1 point. Thereafter, I have used other,
more generous criteria for adjudging the adequacy of care which I will not
detail here. Suffice it to say that if the patient gets cryopreserved under
conditions where cryoprotection is not possible, the score is 3 points.
If we go back to Dr. Bedford, the first patient cryopreserved in 1967, we
see that the best possible score he could have achieved had he been
immediately straight frozen after pronouncement was 15; but because of
grossly inadequate post-arrest and pre-freezing care, his Patient Outcome
Score is only 8. You?ll have to decide for yourself how reasonable my
scoring system is as we go along. But keep in mind; it is designed to serve
only as a relative indicator, not as an absolute measure of performance, nor
of patient recoverability."

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