This is a remarkable statement from Ben Best, and one that perhaps speaks best as to why CI is not a cryonics organization being run on a rational, scientific, evidence based basis. When Ben Best writes: “There is no incompatibility between DMSO and PEG. The PEG make the solution hyperoncotic as the expected. My big mistake, and it was a bad one, I acknowledge, is that most of the vitrification solution was ruined because I was not aware that PEG would come out of solution when placed in a freezer.,” he is making a statement that has the following outright errors, misunderstandings or distortions in it:
First, DMSO and PEG are incompatible in that they cannot be used either safely or effectively under the conditions required to carry out cryoprotective perfusion in a clinical (or research) setting. The first fact to consider is that DMSO-PEG solutions will often undergo gel formation when cooled to temperatures above freezing if left under refrigeration long enough. This phenomenon has a variable time course and is akin to nucleation and freezing in supercooled solutions—such mixtures may remain clear for days, or undergo precipitation/gel formation within hours of cooling.
Second, the perfusate in question, VM-1 is designed to be administered at a SUBZERO temperature in order to minimize toxicity. The final concentration of cryoprotectants in VM-1, a roughly equal mixture of DMSO and ethylene glycol (the latter is the principal ingredient in automotive antifreeze) is ~ 70%! In the brain tissue slice experiments performed by CI’s researcher Dr. Yuri Pichugin who invented VM-1, this very high concentration of agent was not introduced until the temperature of the brain tissue was −20 degrees C! CI’s own protocol calls for the introduction of VM-1 at the lowest possible temperature that they can achieve, given that they have no heat exchanger in their patient perfusion circuit. The way CI attempts to get the temperature of the final pass of VM-1 below 0 degrees C, and as close to to −20 degrees C as possible, is by the expedient of placing bottles containing the perfusate into a standard household-type freezer. The pre-chilled bottles of perfusate are then loaded into picnic chests and the perfusate is dispensed from there.
This Mickey Mouse operation rsults in perfusate that is at some (variable) subzero temperature when it is pumped through the perfusion circuit and delivered to the patient.
Refractive Index values only taken during CI−VM−1 perfusion
This is a remarkable statement from Ben Best, and one that perhaps speaks best as to why CI is not a cryonics organization being run on a rational, scientific, evidence based basis. When Ben Best writes: “There is no incompatibility between DMSO and PEG. The PEG make the solution hyperoncotic as the expected. My big mistake, and it was a bad one, I acknowledge, is that most of the vitrification solution was ruined because I was not aware that PEG would come out of solution when placed in a freezer.,” he is making a statement that has the following outright errors, misunderstandings or distortions in it:
First, DMSO and PEG are incompatible in that they cannot be used either safely or effectively under the conditions required to carry out cryoprotective perfusion in a clinical (or research) setting. The first fact to consider is that DMSO-PEG solutions will often undergo gel formation when cooled to temperatures above freezing if left under refrigeration long enough. This phenomenon has a variable time course and is akin to nucleation and freezing in supercooled solutions—such mixtures may remain clear for days, or undergo precipitation/gel formation within hours of cooling.
Second, the perfusate in question, VM-1 is designed to be administered at a SUBZERO temperature in order to minimize toxicity. The final concentration of cryoprotectants in VM-1, a roughly equal mixture of DMSO and ethylene glycol (the latter is the principal ingredient in automotive antifreeze) is ~ 70%! In the brain tissue slice experiments performed by CI’s researcher Dr. Yuri Pichugin who invented VM-1, this very high concentration of agent was not introduced until the temperature of the brain tissue was −20 degrees C! CI’s own protocol calls for the introduction of VM-1 at the lowest possible temperature that they can achieve, given that they have no heat exchanger in their patient perfusion circuit. The way CI attempts to get the temperature of the final pass of VM-1 below 0 degrees C, and as close to to −20 degrees C as possible, is by the expedient of placing bottles containing the perfusate into a standard household-type freezer. The pre-chilled bottles of perfusate are then loaded into picnic chests and the perfusate is dispensed from there.
This Mickey Mouse operation rsults in perfusate that is at some (variable) subzero temperature when it is pumped through the perfusion circuit and delivered to the patient.
Refractive Index values only taken during CI−VM−1 perfusion
TIME (AM) TEMP (ºC) Flow rate (liters/minute) Pressure mm Hg RJVRI LJVRI 1:11 3.2 1.13 127
1:14 3.8 1.06 131
1:20 5.5 1.36 120 1.3976
1:26 7.0 1.07 117 1.3986
1:30 5.6 1.32 103 1.4017 1.4167 1:35 4.9 1.4048
1:37 4.1 1.4258 1.4242 1:40 3.5 1.4043 1.4183 1:45 2.5 1.4137 1.4209 1:47 2.0 1.4153 1.4224 1:50 1.6 1.15 139 1.4207 1.4236 1:52 Upper Body Perfusion Halted
2:00 Lower Body Perfusion Begun
2:00 0.5 0.42 121
2:03 0.5 0.32 136
2:05 0.5 0.32 134
2:10 0.5 0.31 143
2:13 0.5 0.40 200
2:15 0.5 0.46 185
2:20 0.5 0.46 175
2:25 0.5 0.48 191
2:33 0.5 0.48 174
Lower Body Perfusion Halted
Dry Ice Slurry Added to Head
2:37 −2.0