X-Message-Number: 7732 From: Brian Wowk <> Date: Sun, 23 Feb 1997 02:06:37 -0600 (CST) Subject: New Technology Questions Regarding new fluorocarbon cooling technology, Peter Merel writes: >to what extent has this technology been proved? I'm not expecting >beating rat-hearts, but is there anything demonstrable at the present >time? The technology has been used to cool and rewarm dogs from deep sub-zero temperatures at rates consistent with what we had theoretically expected. There has been no attempt yet to reversibly vitrify organs. Efforts are currently focussed on preparations to do whole cryopatients with a basic vitrification solution that will eliminate freezing damage and give good ultrastructural preservation (no dissolved membranes, etc.), but still be too toxic for true suspended animation. >what obstacles does this leave for Prometheus to tackle? What will >be Prometheus's role in the further development of this technology? A lot of work will be required to develop vitrification solutions that not only prevent ice formation, but that are sufficiently non-toxic to permit neurological recovery. The development of experimental models (including in-situ brain cryopreservation) that convincingly demonstrate neurological recovery will itself require millions of dollars and years of effort. There is still an enormous amount of work to be done. Recent breakthroughs are at best an improved proof-of- concept for Prometheus, proving that vitrification technologies so far only implemented on rabbit organs (by other labs) will be scalable to large systems. It should also be mentioned that a substantial part of the half million-dollar budget for 21st Century Medicine in 1997 covers operations overhead, cerebral ischemia research, and new life extension drug studies unrelated to cryobiology. 21st Century Medicine is still nowhere near being a Prometheus Project, although I like to think we proving ourselves worthy of playing a significant role. >- what sort of conditions will attach to licenses? Reasonable ones, I should think. New technologies aren't worth much unless they are made available to people who need them. One issue that should be given serious consideration by all organizations is the possibility of centralized processing of ideal cryonics cases. The capital costs for computer-controlled sub-zero perfusion and fluorocarbon cooling are extremely high. It would make the most economic sense for organizations to share use of such a facility. That would also simplify issues such as equitable access to Prometheus Project technologies. >presuming that this works out, what's 21C's most optimistic estimate >of the date of the first real cryonic resuscitation of a whole live >live animal? Most pessimistic estimate? Cryonics has previously minced (frozen) and poisoned its patients. By next year we will have the hardware and computer control in place to reduce the problem to just poisoning. We are optimistic that the "poisoning" problem can be overcome because kindeys (a very toxicity-sensitive organ) can now be loaded and unloaded with vitrifiable concentrations of cryoprotectant and survive. So we'll start by optimizing cryoprotectant toxicity to allow for brain recovery, and work our way outward from there. As to timelines, I think we are still looking at years for perfected brain preservation, and decades for whole-body suspended animation. But in the meantime cryonics is going to get MUCH more likely to work. Arkady Elgort <> writes: >Congratulations to the 21CM on this new and potentially exciting >developments! >A few questions: Has this fluorocarbon been already tested in organs? Yes. Lungs and kidneys survive exposure with no apparent harm. This is expected given the totally inert, immiscible nature of the compound. >Was there significant vasoconstriction due to extremely cold perfusate? No. Vasoconstriction doesn't occur at sub-zero temperatures. >What about kidneys vitrification? How soon we can expect to see >RF-rewarmed viable unfrozen kidney? These experiments are being performed by Greg Fahy's group at NAMRI at this very moment. We should know very soon (weeks or months) if this approach will work without problems. Thomas Donaldson writes: >The vitrification results announced are truly very interesting. One issue >is left out: at what temperature should vitrified patients be kept for >long term storage? Does this method still work if we take them down to >LN temperature or does it require a higher temperature? Interesting and important question. Homogenous vitrified solutions are know to fracture below about -140'C. It's quite possible (perahps even likely) we will need a -130'C storage capability to avoid fracturing vitrified cryonics patients. We'll soon see. >And, of course, since we've just come from a situation where the >experiments failed, how much experimental work has been done on this >system? Experiments or not, it does look like a good idea. A large animal (dog) was cooled to -85'C at about 1'C per minute, and then rewarmed at 10'C per minute. The dog was not loaded with a vitrifiable concentration of cryoprotectant for this experiment, so the cooling rate was deliberately slow to avoid intracellular freezing. We know from the rewarming rate, though, that we could have easily cooled at 10'C per minute if we wanted. An important side-benefit of fluorocarbon cooling, even during ordinary freezing, is that the fluorocarbon compound itself vitrifies instead of freezing on deep cooling. It therefore functions as an excellent intravascular cryoprotectant, totally preventing ice formation inside blood vessels. Electron micrographs of fluorocarbon cooled frozen brain show a dramatic reduction in pericapillary ice holes, and a perfectly intact capillary bed. This vascular cryoprotection is a very important benefit from the standpoint of allowing easy access for future nanotech repair devices. *************************************************************************** Brian Wowk CryoCare Foundation 1-800-TOP-CARE President Human Cryopreservation Services http://www.cryocare.org/cryocare/ Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=7732