X-Message-Number: 26716
From: 
Date: Thu, 28 Jul 2005 10:47:03 EDT
Subject: testing solutions

Someone wrote:

"It's  extremely unlikely that Pichugin's solution is as good as M22. 
It's easy  to make a mixture of cryoprotectants that will vitrify at
any cooling rate,  especially if you don't use electron microscopy to
check the  preservation.  It's making a mixture with low toxicity that
is very  hard."


Dr. Pichugin has tested all the best solutions known to him, and continues  

further testing, with emphasis on toxicity or viability. The main tool so far,
as I understand it, is the potassium/sodium ratio, which is generally 

believed  to be a very broad indicator of overall viability, much more sensitive
than 
 electron microscopy. Microscopy indicates structure (within its limits, and 
with  many possible artifacts), while the K/Na rato indicates function. You 

can have  apparently good structure without function, and function is the bottom
 line.
Good structure is better than poor, and even poor structure may be  
eventually reparable, but Dr. Pichugin's standard is the toughest.
 
Ideally we want all kinds of verification, and we are working on it. It's  

difficult and expensive, and therefore slow. As far as I know, nobody--nobody,
nobody, nobody--has yet vitrified a whole mammalian brain and quantified  the 
results in various segments and subsegments. We (everybody) make  our best 
guesses and take our chances, and gradually advance.  Eventually there may be 
some convergence and consensus, but that does not appear  close. 
 
A few months ago, when Joe Waynick visited, he expressed a desire for more  
cooperation, including research. However, as I understand it, Alcor is not  

independent but constrained by legal agreements with 21CM, so I don't know  what
the answer to that is.
 
Again, Ben is still out of town, and may have something more or different  to 
say.
 
Robert Ettinger
 
 


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