X-Message-Number: 8901 From: (Ken Stone) Subject: re: Why use humans for research instead of animals? Date: Fri, 05 Dec 1997 20:34:31 GMT References: <> >From: Stephen Bogner <> > >I may have missed the premise of the "Donate Bodies for Research" thread. > Why are dead and dying human subjects preferred over animal models for >research? Surely the state of research is not so far advanced that the >subtle difference between an animal model and a human model has become an >issue. I think there are some big questions where those differences might not be at all subtle. I know there have been a few cranial burr-hole tests which have given some hope, but I don't think anyone really knows if current suspension protocols are adequately perfusing the brain. Furthermore, because cryoprotectants are themselves fairly toxic at the temperatures where they aren't too viscous to be used, there's a very tricky balance to be maintained: if the perfusion concentrations are inadequate, the patient's brain will suffer mechanical freeze damage that is likely to be irreversible. (Sorry, I'm not a big believer in capital 'N'-style Nanotechnology.) And then even if the cryoprotectant perfusion *is* effective, their brains may already be destroyed chemically before the patients ever rech LN2 temps. Great options, huh? Maybe some day, our friends in the future will be able to fix such damage. But maybe not. Some schemes are in place which try to walk the "not too much"/"not too little" line, but without being able to carefully examine the results of real suspensions on real people, we can only speculate about how effective they really are, and hope. (If that's good enough for you, so be it, but with so much Faith, you might be better off considering options other than cryonics anyway.) As to your question about animal models: Human brains are quite a bit larger and rather differently structured than most other members of the animal kingdom. We can expect that the vasculature and perfusion requirements will be noticeably different as well. For those creatures which MIGHT not be so different (e.g. dolphins, chimpanzees, great apes), you're going to have a hard time convincing me that slaughtering them (with unknown applicability) while simply letting unfunded people die is somehow preferential to a scheme which gives at least some hope to THOSE PEOPLE WHO WANT IT. And who knows? Perhaps researchers might even be able to devise techniques that will allow them to very cleanly dissect and examine brain structures while preserving them at or near LN2 temp. Then they could return the pieces to storage after examination, knowing that even sliced-up brains might someday be repaired. Ken Stone Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=8901