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