X-Message-Number: 15279
From: 
Date: Sun, 7 Jan 2001 12:05:40 EST
Subject: vitrification # 5

This is instalment 5 of my sometime series on vitrification-actually a 
continuation of instalment 4.

As previously noted, the recent vitrification research--related to 21CM, INC 
and others--is interesting, praiseworthy, and potentially valuable, as is the 
effort by Alcor to utilize it. But Alcor's enthusiasm in exploiting it for 
public relations is in my opinion clearly excessive. In particular, I refer 
to Fred Chamberlain's article in the current CRYONICS and on the Alcor web 
site, proclaiming "Vitrification arrives!"

Vitrification has not arrived. Or if it has, it isn't exactly new, even 
though there may now be newer and better procedures. I commented on reports 
of possible vitrification in THE PROSPECT OF IMMORTALITY almost 40 years ago. 
What would be new in the Hallelujah sense is confirmed vitrification of 
mammalian brains, examined after rewarming from long term storage temperature 
and showing minimal damage from at least three standpoints--histology 
(microanatomy), physiology (chemical functions), and electrophysiology 
(neural net function). 

This has not happened--NOT ANY PART OF IT. The Alcor claim is based on 
evidence that is partial, indirect, and lacking confirmation by independent 
investigators. The very small samples mentioned did not go below - 80 C (at 
least - 130 C is required), and the one chemical test applied (the 
potassium/sodium ratio) showed only about 53% cell survival. And that was 
based on a solution LESS concentrated than the one Alcor used, and was 
applied to rat hippocampal slices, not to specimens from brains given Alcor's 
treatment.

Now some further remarks on form vs. function. I and others have pointed out 
previously that, if one must choose between preserving structure and 
preserving function, there is no easy or reliable way to decide. So far, all 
cryonics organizations have chosen to emphasize function over structure. That 
is, we use cryoprotection rather than chemical fixation because freezing or 
vitrification often allows revival of biological specimens, whereas chemical 
fixation ("embalming" etc.) never has. But Drexler and others have noted 
that, from a nanotech repair point of view, the latter might be better. Doug 
Skrecky also has some recent comments in this area. Further investigation is 
on our agenda.

Next, I want to look briefly at a relatively recent paper: "Determination of 
optimal cryoprotectants and procedures for their addition and removal from 
human spermatozoa," by J.A. Gilmore, J. Liu, D.Y. Gao, and J.K. Critser, 
HUMAN REPRODUCTION vol. 12 no. 1 pp 112-118, 1997.

What is so interesting about this? Not the results, to any important 
extent--from a cryonics point of view, cryopreservation of spermatozoa has 
little or no relevance. But it could be useful, especially for newcomers, in 
two ways--first, to gain a little insight into the problems of 
cryopreservation; second and more importantly, to gain some perspective on 
progress and time scales in cryobiology.  

The Introduction includes the following, shortened and paraphrased:

CPAs (cryoprotective agents) either maintain solute concentrations, inside 
and outside the cells, at tolerable levels (permeating CPAs); or they may 
partially dehydrate the cells, stabilizing cell membranes (non-permeating 
CPAs). The focus of this study is on the permeating CPAs glycerol, DMSO 
(dimethylsulfoxide), propylene glycol and ethylene glycol.

CPAs place osmotic stress on cells, which after exposure to permeating 
solutes first shrink as water leaves through the plasma (cell) membrane, and 
then swell as water re-enters along with CPA. During removal of solutes, 
sells first swell as water enters, then slowly return to iso-osmotic (normal) 
volume as CPAs and water leave. 

PROCEDURES MUST BE OPTIMIZED ACCORDING TO SPECIFIC CELL CHARACTERISTICS TO 
ASSURE SUCCESSFUL CRYOPRESERVATION.
Many years ago, Alcor was constantly claiming to have "state of the art" 
procedures--meaning, of course, their own current capabilities. I pointed out 
that this was not really the case, because "state of the art" would really 
mean applying to each cell type, or at minimum each tissue type, just that 
procedure found most effective in its case. That would mean many teams of 
surgeons operating at once (if they could keep their elbows in close enough). 
Needless to say, it is doubtful that even Bill Gates could keep many teams of 
surgeons on constant standby, even if the technical problems could be solved.

But what about the fact that some small animals--larval insects, for 
example--and some small mammalian organs--rat parathyroid, for example--have 
been reported revived after liquid nitrogen storage? Several decades ago, 
that seemed hopeful to many, including me. But such reports have been scant, 
and confirmation by other investigators even more sparse, and the criteria of 
long term survival not always clear.

So perhaps we should take an intermediate stance. We know that different cell 
types have different requirements for optimal cryopreservation. (For that 
matter, different individual cells in a sample can differ, some surviving and 
some not!) But in some cases a compromise may allow a relatively simple 
tissue or organ to survive, at least to some extent, by a single procedure. 
The surviving tissue or organ might then heal itself over time. This view 
allows a degree of optimism for--say--human kidney cryopreservation in coming 
years.

But we are dealing with human brains--orders of magnitude more complex in 
some ways than any other biological system. The idea that some single 
compromise procedure will result in full viability after cryopreservation 
(without nanotech repair) is surmise, at best. 

How distant is it likely to be in time? The paper above mentioned again 
provides at least a hint. Cryopreservation of sperm is one of the oldest 
topics in cryobiology--more than half a century. If the professionals are 
STILL studying and debating the best methods for preservation of sperm (and 
blood and many other things) after all this time, is it reasonable to expect 
full success with the human brain in just a few more years?

The upshot, as I see it:

"Suspended animation" is far down the road. "Vitrification" is not "the" 
answer, now or for a long time to come. Nanotech repair will be necessary to 
recover all patients of the past or the near future. It will also probably be 
sufficient to recover all current patients, and the likelihood of success 
increases as we reduce the damage. Thus we have ample reason both for hope 
for patients of the present and near future, and for further and more 
vigorous efforts in research AND in growth of the cryonics organizations.

Robert Ettinger
Cryonics Institute
Immortalist Society
http://www.cryonics.org

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