X-Message-Number: 26749
From: 
Subject: Brain vitrification
Date: Mon, 01 Aug 2005 23:13:04 +0000

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In Cryomsg 26744, Bob Ettinger wrote:

>>

The references cited (Lemler et al) were useful and encouraging, but  glossed 
over some points. A hasty reader might conclude that brain vitrification with 
liquid nitrogen storage is a done deal...

The  lowest reported temperature was - 140 C, and the period of time  at that 
temperature was not given.
<<


Brain vitrification with liquid nitrogen storage is a done deal, and has been 
for some time, subject to the caveat that whole brains vitrified with current 
solutions will not spontaneously resume function after warming because of 
cryoprotectant toxicity (and fracturing if cooled all the way to liquid nitrogen
temperature).  As Bob should know, between -140 degC and -196 degC there are no
further damage mechanisms other than fracturing. 

>>
...and also that rabbit kidneys can be  

vitrified well enough for routine transplant. This does not seem to be the case.
The rabbit kidney results could be read as  long 
term survival of vitrified transplants, but it didn't actually say that, 
<<


Since it didn't actually say that, I don't know why it could be read as that.  
The M22 kidney paper was published in the journal Cryobiology last year, and is 
well-known in the vitrification field.  I'm pretty sure it was discussed on 
CryoNet, but even if not I'm surprised it was not noticed on PubMed by 
cryonicists who follow vitrification research.  The full text is available at

http://www.21cm.com/pdfs/cryopreservation_advances.pdf  
 
>>

 And the composition of the solution "M22" was not given, so there is no way for
 us to do any independent verification.
<<


The formula for M22 has been in the open literature for more than a year.  It is
in the above paper, along with many other properties such as glass transition 
temperature, melting point, nominal pH, and toxicity results.  Two other 
properties presented at this year's Society for Cryobiology meeting were a 
critical cooling rate (minimum rate for cooling large volumes without ice 
formation) of 0.1 degC/minute, and a critical warming rate of 0.4 degC/minute.  
There is a photograph of a large volume of M22 vitrified without ice formation 
in the middle of the page

http://www.alcor.org/sciencefaq.htm

>>
The secrecy issue is an unsolved problem...
(we should) Publish our results  freely as 
they come...
<<

Alcor's cards are now on the table.

David Stodolsky wrote:

>>

The commercially-oriented tissue preservation work may, therefore,  not be what 
yields the best result for cryonic suspension.
<<


The structure/function tradeoff is not as stark as it appears.  Decent structure
preservation is typically a pre-requisite for good function preservation.  
However, as I've already told Bob privately, I don't believe there is any 
vitrification solution in the world that gives good functional recovery under 
the time/temperature/concentration conditions of human cryonics.  There are only
functional results under less damanding conditions, from which we suppose that 
less toxic solutions cause less biomolecular havoc in cryonics.


As for "commercially-oriented tissue preservation", the only vitrification 
solution for which structural brain vitrification data has been published is a 
commercial solution developed to minimize toxicity, so for now there is no 
dichotomy.   

---Brian Wowk
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