X-Message-Number: 15249
From: 
Date: Wed, 3 Jan 2001 23:18:07 EST
Subject: Vitrification and Evaluation

This is instalment 4 of my sometime series on vitrification.

First, again, the intent is not to belittle or denigrate the researchers at 
21CM and INC etc., nor the efforts of Alcor to improve its procedures--only 
to caution against exaggerated perceptions or inflated expectations.

Today I focus mainly on methods of evaluating the results of cryopreservation.

Referring again to Fred Chamberlain's article in the 4th quarter 2000 issue 
of CRYONICS (the Alcor publication) starting on p. 4, we see the headline 
"Vitrification Arrives" and the subhead "New Technology Preserves Patients 
without Ice Damage." 

The introduction contains several qualifiers, including: "This is not a 
report of scientific findings; rather, it is a statement of steps being taken 
toward applications of new technologies by Alcor and BioTransport Inc." 
However, it also says that "Details of the technical aspects, to the point of 
specific phraseology, are largely supplied by researchers involved, yet their 
names do not appear here." Clearly, the thrust of the article is to convey 
the impression that it is indeed a report of very scientific--and very 
important--findings.

I think I can fairly summarize the main evidence of efficacy presented in 
this article as follows:

1. Vitrification is better than freezing, in principle, because ice crystals 
do not form, and ice crystals can result in mechanical and other damage to 
cells and tissues.

2.  Animal brain tissue cooled to - 80 C with a vitrification solution and 
then rewarmed shows much better looking microphotos than tissue similarly 
treated with a freezing solution.

3. There are published reports of blood vessels vitrified all the way down to 
- 130 C (in the neighborhood of long term storage temperature) without 
structural damage, suggesting that the same might be true for brains--even 
though no such example of brains is given, and even though one of the oldest 
lessons of cryobiology is that results with one kind of tissue cannot usually 
be generalized to other types.

4. Toxicity of the solution is said to be relatively low. This is based on 
experiments with slices from the hippocampus of the rat brain, using a 
similar but LESS concentrated solution, which resulted in 53% viability 
relative to untreated controls. This is believed to mean that about half the 
cells survived, as determined by a single chemical/physiological criterion, 
the potassium/sodium ratio. It also means, of course, that almost half of 
them died, or at least were not restored to function.

The details of the vitrification solution are not given, so that others (we 
at CI for example) cannot conduct confirming experiments. Someone might 
dismiss this by saying that we lack the means for sufficiently fast cooling 
of human patients anyway, but that would miss the point. We could certainly 
vitrify small pieces of brain tissue fast enough, and evaluate the results. 
So our (or anyone's) independent confirmation will apparently have to wait 
until enough time passes, or the right contracts are signed, to protect the 
proprietary interests involved. Let's leave that aside for the moment.

Fred acknowledges that, at least for the time being, Alcor neuropatients so 
treated will have to be stored in liquid nitrogen, since reliable equipment 
for long term storage in the neighborhood of - 130 C to - 150 C is not yet at 
hand. He also notes that cooling vitrified patients down to liquid nitrogen 
temperature is likely to result in fracturing, and that fracturing would 
require an advanced nanotechnology for repair, as would freezing. This 
appears to amount to an acknowledgement that Alcor's two most recent 
patients, "vitrified" neuros, now I believe in liquid nitrogen, are likely to 
require a mature nanotech for recovery.

Fred says, "If fracturing can be avoided, vitrification provides a means of 
achieving perfect structural preservation of cryopatients." This is very 
clearly a gross overstatement on the basis of what we currently know. But 
let's look again at structure and function.

STRUCTURE vs. FUNCTION

Which is more important--to preserve structure or to preserve function?

This is a complicated question with no simple answer. An analogy may help 
show some of the problems.

Which would you rather have--a brand new auto with a loose ignition wire, or 
an old clunker that is still puttering along?

The choice is clear--yet the former is DEAD (won't run at all) whereas the 
latter is still running. In this case, structure is the obvious choice over 
function.

However, the cryonics organizations so far have chosen function over 
structure. Chemical fixation--something similar to embalming--preserves 
structure (microanatomy) better than freezing, in many cases maybe as well as 
vitrification or better. But many biological specimens have been revived 
after freezing, none after fixation. Have we been guilty of an irrational 
bias?

Some knowledgeable people--perhaps the best known being Drexler--have 
advocated fixation, or some combination of fixation and low temperatures. 
Fixation, along with drying or freeze-drying, still are worthy of 
investigation. But it's hard to sell the idea of pickled people, and no one 
is likely to spend a lot of resources in this way any time soon.

Alcor claims excellent structural preservation for its current procedure 
(based on incomplete and indirect evidence), while admitting that only about 
half the cells survived one functional test, that test using a less 
concentrated solution. 

Whoosh! I've barely gotten started on this segment, but it's getting late and 
the rest will have to wait.

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

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