X-Message-Number: 2943 From: (Thomas Donaldson) Subject: CRYONICS: RE: question of Brian Wowk Date: Tue, 26 Jul 1994 08:58:38 -0700 (PDT) Hi! This is a reply to Brian Wowk's posting in which he expresses amazement that a doctor would be so dumb as to believe that blood clotting played a central role in the death of brain neurons after a period without circulation. Brian, I also think the doctor is wrong, because what really happens is still very complex and hasn't been worked out in detail well enough for clinical application on a routine basis. But I also think that his focus on blood coagulaton in arterioles and venules in the brain does have something to it .. you may recall, for instance, the Medical World News story of almost 10 years ago, in which a gang member was brought in about an hour after being stabbed and has bled to death ie. lost lots of blood. Fortunately for this patient, the doctor handling the emergency ward at that time had actually been doing research on the problems of revival after the "3 minute limit" (or is it officially 5 minutes?). The patient was revived successfully after an hour of ischemia at normal temperature. I strongly suspect that the fact that he had bled to death had something to do with it, though the doctor (a Dr. Brian White) also used drugs --- everything he could think of, in fact. I would point out that similar things seem to happen in Hossmann's experi- ments too. Is the brain a particularly friendly site for blood coagulation? Without doing a lot of literatures searching (I'm writing this without consulting sources, I admit) we do know that brains provide a different environment. After all, there is the blood-brain barrier to start (a metabolic, not a physical barrier) and I don't find it unlikely that different organs will show blood clotting at different rates. But as I said in the beginning, what really happens is far more complex than just blood coagulation. Best and long long life, Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=2943