X-Message-Number: 2484 From: Ralph Merkle <> Subject: CRYONICS Re: Brain Injury Date: Fri, 10 Dec 1993 11:55:39 PST >From "The Technical Feasibility of Cryonics" by Ralph C. Merkle, extended version: Temporary and sometimes even permanent functional recovery has been demonstrated in optimal situations after as long as 60 minutes of total ischemia[93, 94, 95]. Hossmann, for example, reported results on 143 cats subjected to one hour of normothermic global brain ischemia[97]. "Body temperature was maintained at 36 degrees to 37 degrees C with a heating pad. ... Completeness of ischemia was tested by injecting Xe 133 into the innominate artery immediately before vascular occlusion and monitoring the absence of decay of radioactivity from the head during ischemia, using external scintillation detectors. ... In 50% of the animals, even major spontaneous EEG activity returned after ischemia.... One cat survived for 1 yr after one hour of normothermic cerebrocirculatory arrest with no electrophysiologic deficit and with only minor neurologic and morphologic disturbances." Functional recovery is a more stringent criterion than the more relaxed information theoretic criterion, which merely requires adequate structural preservation to allow inference about the pre-existing structure. Reliable identification of the various cellular structures is possible hours (and sometimes even days) later. Detailed descriptions of ischemia and its time course[72, page 209 et sequitur] also clearly show that cooling substantially slows the rate of deterioration. Thus, even moderate cooling "postmortem" slows deterioration significantly. 72. "Cell Death in Biology and Pathology" edited by I. D. Bowen and R. A. Lockshin, Chapman and Hall, 1981. 97. "Resuscitation potentials after prolonged global cerebral ischemia in cats" by Konstantin-Alexander Hossmann, MD, Ph.D., Critical Care Medicine, Vol 16, No. 10, 1988, page 964-971. Other references of interest: 93. "Neurochemical Determinants of Ischemic Cell Damage" by Carl- Henrik Nordstrom, M.D. and Bo K. Siesjo, M.D., pages 49-66; from "Protection of the Brain from Ischemia" edited by Philip R. Weinstein and Alan A. Faden, Williams and Wilkens 1990. 94. "Hemodynamics of Postischemic Reperfusion of the Brain," by K.-A. Hossmann, M.D., Ph.D., pages 21-36; from "Protection of the Brain from Ischemia" edited by Philip R. Weinstein and Alan A. Faden, Williams and Wilkens 1990. 95. "Post-ischemic resuscitation of the brain: selective vulnerability versus global resistance" by K.-A. Hossman; from Progress in Brain Research, Vol. 63, edited by K. Kogure, K.-A. Hossman, B. K. Siesjo and F. A. Welsh, 1985, pages 3-17. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=2484