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 Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=1732