X-Message-Number: 1732
Date: 10 Feb 93 14:12:55 EST
From: Garret Smyth <>
Subject: CRYONICS Polymers

Although I don't know much about the polymers mentioned in the thread so 
far, but I'd thought I'd mention  a paper in "Cryo-letters" Vol 14, No 1,
Jan/Feb 1993 by RL Sutton and DE Pegg page 13.

	"Devitrification in Butane-2,3-diol Solutions Containing
	Anti-freeze Peptide"

The summary is as follows:

"Cryopreservation of viable and organs by vitrification requires that
devitrification (freezing) be prevented during warming. We report that a
synthetic antifreeze, modelled on the natural peptide found in the Winter
Flounder *Pseudopleuronectes americanus*, substantilly raises the
devitrification temperature of solutions of the cryoprotectant
butane-2,3-diol. The addition of 1% w/w peptide reduces the minimum
warming rate to avoid devitrification of  a 30% solution by a factor of
7000."

The main problem, that I would have predicted, with using any kind of a
polymer in vivo is that it would not easily cross the walls of blood
vessels and cell membranes and especilly the blood-brain barrier.

Incidentally, the address given for David Pegg in this is at the MRC
Medical Cryobiology Group, Department of Surgery, Camridge, which, I have
heard, has since been shut down. I believe that he has managed to
transfer his researches to York University's biology dept.

Garret

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