X-Message-Number: 7673 From: Brian Wowk <> Date: Sun, 9 Feb 1997 23:12:13 -0600 (CST) Subject: Re: Cryo Journal Club 1 Thanks to Jan Coetzee for posting the abstract on fracturing damage during rapid cooling/rewarming of small vitreous samples. An even more interesting work relevant to the problems of vitrifying human cryopatients is the paper "Physical Problems with the Vitrification of Large Biological Systems" by Fahy, Saur, and Williams, Cryobiology 27, 492-510 (1990). This work concludes that "fracturing depends strongly on cooling rate and thermal uniformity and can be postponed to about 25'C below Tg for a 482-ml sample if cooling is slow and uniform." In general, it appears from this study that fracturing of large vitreous solutions can be avoided above the glass transition temperature (Tg) with careful cooling as Tg is approached. Avoiding fracturing far below Tg (about -110'C for typical cryoprotectants) appears to be a more difficult problem that may necessitate the development of high-temperature (-130'C) storage systems for vitrified cryopatients. *************************************************************************** Brian Wowk CryoCare Foundation 1-800-TOP-CARE President Human Cryopreservation Services http://www.cryocare.org/cryocare/ Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=7673