X-Message-Number: 6952
From:  (Brian Wowk)
Newsgroups: sci.cryonics
Subject: Re: Cooling Rate issue
Date: 19 Sep 96 17:41:28 GMT
Message-ID: <>
References: <> <>

In <> Terry Lambert <> writes:

>This raises a number of other, related issues, then, which are
>implied by the lower rate.  Foremost might be the issue of how
>efficient is the Visser CPA as an oxygen transport.

	Don't worry about it.  Cells don't have much use for
oxygen below 0'C.  CPA is not introduced at higher temperatures
because of toxicity.  The technology for getting from 38'C to
0'C with minimum injury is a separate specialty that is 
CPA-independent. 

>I'm there are a large number of worms in the slow-cooling can.

	The biggest is going to be toxicity.  We don't know 
what this agent will do to organs exposed to it for hours
at high sub-zero temperatures.  Not so much an issue for
hearts, but it certainly will be for brains.  

>On the plus side, I'll note that gross function was restored
>post thawing in the reported experiments.  The thawing, without
>RF heating or similar fast-thaw techniques, seems to me to be
>supporting evidence.

	The most encouraging aspect of the slow thawing 
success is that it shows the heart will survive exposure to
high (eutectic) concentrations of the agent for many
minutes.  Whether this survival time will be sufficient
for cooling and thawing (with RF if necessary) of large
hearts remains to be seen.  The experiments must be done;
done at realistic cooling rates, and on each organ
individually.

***************************************************************************
Brian Wowk          CryoCare Foundation               1-800-TOP-CARE
President           Human Cryopreservation Services   
   http://www.cryocare.org/cryocare/

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