X-Message-Number: 5805 From: (Brian Wowk) Newsgroups: uk.legal,sci.cryonics,sci.life-extension Subject: Re: Death (was Donaldson MR and Miss Hindley) Date: 22 Feb 96 06:52:50 GMT Message-ID: <> References: <> <> In <> Marshall Rice <> writes: >In article <> "Brian Wowk" writes: >> (c) Freezing injury is the most serious injury that occurs to >> cryonics patients, but your comments suggest that you >> vastly overestimate it. Check out >> >> http://www.cryocare.org/cryocare/casecryo.txt >> >> to see how robust neural tissues (particularly synapses) are >> when subjected to freezing. I'd love to show you some >> electron micrographs. Unfortunately this medium >> is not conducive to it. >What, pray, would such electron photomicrographs demonstrate, other than the >fact that the hardware was *relatively* resilient? What about the neural >characteristics of frozen synapses? What is known? Check out the full description of what can be seen in these micrographs in BPI Tech Report #16 in the Services/BioPreservation section of our Web page. Just to show that maybe there really is a God :), synapses are among the most freeze tolerant cell structures in nature. They are the "Eveready Energizer Bunnies" of cryobiology. In the Cryobiological Case for Cryonics (in the Library section of our Web page), there are numerous studies referenced in which synapses are frozen under all kinds of suboptimal, abusive conditions, yet still recover metabolic function after thawing (as measured by neurotrasmitter uptake, oxygen utilization, and a half dozen other paramaters). >With the greatest of respect, the term "Medical Physicist" encompasses everyone >from consultant medical radiobiologists to x-ray technicians. Where in that >spectrum does your qualification and expertise lie? A Masters degree in radiation therapy physics, with four published papers in that field, and now a Ph.D. candidacy in MRI physics. And no, x-ray technicians are not encompassed by the term "medical physicist." >Thank you for your little lesson in radiobiology. I am perfectly well aware of >the mechanism of cellular damage by ionising radiations, thank you. As a matter >of fact, the main culprit is the OH- radical.... Unless you are going to argue that radiation is orders of magnitude *more damaging* to tissue in the frozen state, than unfrozen state, we can put this debate to bed right now. Assume as a rough order of magnitude that background radiation is about 1 rad per year. LD50 is 400 rads. However, if you can fix and/or replace stem cells (the most vulnerable of all cells to radiation) it is possible to survive 1000+ rads of radiation (delivered routinely to bone marrow transplant patients today). And if cryonics patients are not back in 1000 years, then they are NEVER coming back for reasons that have nothing to do with radiation. >Assumptions such as those can be rather risky. Would you care to discuss >what you have observed and deduced from those photomicrographs and metabolic >studies that you have evaluated? The minutae of observations that can be made are best read in the above quoted references. My conclusion is that protocols now exist for cryopreservation of human neural tissue that leave the original structure almost perfectly intact. Morever, indications are that comparatively modest efforts could bring this technology to perfection: real-time reversible cryopreservation of the human brain, providing a doorway for dying patients today to reach the medicine of the distant future. >> Would it surprise you to learn that in fact much of >> what is now known about human neuroanatomy and neurochemistry was >> learned by the study of frozen brain sections?? >And applies to dead, fixed tissue. Touche. *************************************************************************** Brian Wowk CryoCare Foundation 1-800-TOP-CARE President Your Gateway to the Future http://www.cryocare.org/cryocare/ Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=5805