X-Message-Number: 6885 Date: Thu, 12 Sep 1996 11:24:07 -0400 (EDT) From: Charles Platt <> Subject: Perfusion question On Thu, 12 Sep 1996, Dave Pizer wrote: > Our scientists also informally compared two frozen rat *brains*, one > protected with the Visser technology and one without. There appeared to > be a significant difference (positive) in condition of the one that was > protected. I know this does not answer many questions. Dave, it doesn't answer ANY questions! Specifically: 1. When you say one was protected and "one without," what does this mean? Was one of the brains unprotected by ANY form of cryoprotectant? If so, we would naturally expect it to look worse than the brain that received some protection. On the other hand, if the brain that didn't receive the Visser treatment was protected by some other method, such as current human cryopreservation protocol as used by Alcor, then obviously it is highly significant if the Visser protocol achieved superior results, and I should imagine that Alcor members would be especially eager to hear about this. So, can you please clarify? 2. What is a "significant difference (positive) in condition"? a) How was the difference observed: i) by naked eye under white light ii) by magnifying glass iii) by white-light microscope iv) by electron microscope b) How was the sample prepared for evaluation: i) whole brain ii) dissected brain iii) slices for viewing by microscope (if so, from which regions of the brain) c) In what way did the Visser-protected brain look "better"? i) natural color ii) lack of cracking iii) fewer ice crystals visible with white-light microscopy iv) total absence of ice crystals v) less shrinkage of tissues due to dehydration vi) fewer ice holes in tissues vii) less damage on cellular level (in which case, specific details are needed) d) Was the brain observed in the frozen state, or after rewarming? If it was rewarmed, what was the method used and the temperature gradient at points on the surface and in the center of the brain? e) How rapidly was the brain frozen initially, how was cryoprotectant introduced, what was the concentration used, what was the cooling curve, what was the terminal frozen temperature, how long was it kept at that temperature, and by what method (immersion in liquid, immersion in vapor, in a refrigerator)? Note that none of these questions require Ms. Visser to reveal anything about the composition of her perfusate. These are not a bunch of petty quibbles. These are basic questions, and without the answers there is no way to compare this research with other research. I can certainly understand that you'd like some more money to do more research. We'd all like more money for our research. But in the absence of any explanation of the procedure and results so far, quite honestly you are asking for money while providing even less information than the Prometheus Project (which is merely asking for highly conditional future pledges, not actual donations, specifically BECAUSE it cannot yet answer the necessary questions). I myself would be willing to donate money to Alcor to help with research, if I had a reasonable idea about what the research has achieved so far, what it hopes to achieve in the near future, and what methods may be used. Right now, since you are hoping to hire someone in addition to Hugh Hixon, I'm not even sure who will be conducting this research. A note from Hugh himself might be helpful, here. He, after all, is the one with the science background. I certainly wouldn't attempt to present Mike Darwin's research results for him, if I was asking for money on behalf of Twenty-First Century Medicine. You and I are mere PR people, Dave. Can't the experts speak for themselves? --Charles Platt (speaking for me, not CryoCare) Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=6885