X-Message-Number: 4693 Date: Mon, 31 Jul 1995 01:30:24 -0700 (PDT) From: Doug Skrecky <> Subject: no cellular viability in cryonics? I would be grateful if someone could answer a question I have regarding cryonic procedures. There exist claims to the effect that cryonicists have been able to perfuse their patients with concentrations of glycerol as high as 7 M. This seems to have been regarded as a worthy acheivement as it is felt that this amount of glycerol should reduce freezing damage to minimal levels. However...... When human corneas are gradually exposed (at 4 degrees C) to increasing concentrations of cryoprotectants they experience a REDUCED survival. Using the ramp method increasing the concentration of glycerol from 4.3 M to 5.4 M reduces cellular survival from 98.2% to 52.3%. Increasing from 2 M to 3 M also reduces survival when the cryoprotectants dimethylsulfoxide, 1,2-propanediol and 2,3-butanediol are used, so this loss of viability at high osmolarity appears to be a general phenonmena which occurs with all cryoprotectants This raises a disturbing thought. Are cryonics companies killing their patients? REFERENCE: "Human Corneal Endothelial Tolerance to Glycerol, Dimethylsulfoxide, 1,2-Propanediol and 2,3-Butanediol" 1-9 Vol.31 1994 Cryobiology Sincerely Doug Skrecky Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=4693