X-Message-Number: 15543
Date: Fri, 2 Feb 2001 23:31:01 EST
Subject: Asymptote

One of our people referred me to the web site of a company called Asymptote, 
which makes equipment for freezing specimens for in-vitro fertilization.There 
is some exposition of both freezing and vitrification. 

The brief section on vitrification says the approach is promising but still 
experimental (even for embryos, apparently, although some laboratories have 
reported good survival), and the high levels of additives are potentially 
cytotoxic. It also says practical problems include that of devitrification 
during thawing *or storage.* It did not say at what temperature 
devitrification (ice crystal formation) might occur during storage.

Their own technology apparently involves freezing, not vitrification, and 
leads to good results. 

An interesting point, not seen or even contradicted in some discussions, is 
that (for their particular application at least) it is BETTER if ice forms 
sooner. If supercooling occurs with glycerol protection, for example--ice 
forming only at lower temperatures--then there may be more damage than if ice 
forms sooner at higher temperatures. In fact, they deliberately seed the 
solutions to make ice form sooner. I won't go into the reasons for this just 
now, since it's getting late.

Robert Ettinger
Cryonics Institute
Immortalist Society

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