X-Message-Number: 16570
Date: Sun, 17 Jun 2001 19:53:48 -0400 (EDT)
From: Ben Best <>
Subject: Ice blockers and CI protocol

On Sat, 16 Jun 2001, Charles Platt wrote:

> As has been stated here, 21CM ice blocker is available for purchase by
> any interested party, can be used in conjunction with existing protocol, 
> and had not been purchased by CI (the last time I checked).

    I do not believe that CI should include ice blockers in its
current protocols -- which use high concentrations of glycerol
that will reduce ice formation but not result in vitrification. 
I have strongly advised CI against the use of ice blockers. To 
quote from the ice-blocker section of the vitrification essay on
my website:

         "As a cautionary note, it should be mentioned that use of
    ice-blocker without sufficient cryoprotectant (or rapid-enough cooling)
    to cause vitrification can result in ice formation that is more
    damaging than the ice that would have formed at a higher temperature 
    if no ice-blocker had been used. Ice-formation at higher temperature 
    tends to be extracellular -- and dehydrates the cells. At lower 
    temperature osmosis is less active. So if ice-blockers simply result 
    in ice formation at a lower temperature, the ice that forms at those 
    temperatures is more likely to be inside the cells, thus causing 
    greater damage. "

   For more background, I refer readers to the ice-blocker section of
the vitrification essay on my website:

       http://www.benbest.com/cryonics/vitrify.html

                                  -- Ben Best

         --------------------------------------------
            Ben Best ()
            http://www.benbest.com/

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