X-Message-Number: 7739 From: Date: Sun, 23 Feb 1997 13:43:09 -0500 (EST) Subject: ice & research Sorry, Brian (Wowk)--you weren't paying attention (#7731). Nothing I wrote suggested any misunderstanding of freezing damage, so please don't patronize me. I can certainly make mistakes, but this wasn't one of them. What I said was, first, that expansion of water on freezing is only around 10%, and therefore it is not true, as you said (#7715) that "Even the fabric of cells themselves is crushed into these tiny spaces among the ice crystals." Your statement carried a clear intimation that most of the space is occupied by ice crystals, leaving only tiny spaces for tissue, AND an intimation that essentially all of the water will end up in these ice crystals. This is not the case. Of course (and I could indeed have made this clearer), if ALL the water in cells was withdrawn during the freezing process to form pure ice in the intercellular spaces, or inter-tissue spaces, then the space available for non-water ingredients would be limited to about that fraction of the volume not originally accounted for by water. (This is not a "tiny" volume.) But this is NOT the case. Considerable water--some of it bound with weak chemical bonds--remains in the cells and tissues, especially if there is some appropriate cryoprotective agent. Again I recommend that readers review Greg Fahy's declaration in the Dora Kent case. As you correctly say, we needn't depend on theory for everything; a lot of experimental evidence is available. And electron and light micrographs of specimens prepared in many different ways, while showing a lot of damage, also show a lot of retention of structure. I am struck by a couple of things you say in #7731--that "with a hyperadvanced nanotechnology, even patients frozen under very bad conditions could be revived....[but]...freezing, as it occurs in cryonics today, is a very serious injury that will require advanced nanotechnology for repair." This is just a rephrasing of my long-standing conjecture (although you elevate it above conjecture!) that full-fledged nanotech may be both necessary and sufficient to revive patients frozen by any method heretofore used. Interesting, and with doubtless unintended implications. I suppose I must add, for the umpteenth time, that we need to exploit any advances we can, to reduce the burden on the future and improve our chances. Cryonics Institute and the Immortalist Society are actively supporting and doing research, and we will be happy to see anyone, anywhere, make progress. The trade-offs between cost and benefit will, of course, have to be evaluated at each stage. CI may at some point have to offer a choice of procedures at different prices. I hope this can be avoided, but if a necessarily expensive procedure offers clear benefit, we can hardly freeze out those who can't afford the optimum. And again, I have strong doubts about perfectibility of reversible brain cryopreservation short of full-fledged nanotech. I.e., the problem of suspended animation may be just as difficult as the problem of revival of crudely frozen patients, because of the extreme complexity of the brain. I hope I'm wrong about that, and I don't say it to discourage research, but like it or not it is another element in the cost/benefit equation. Robert Ettinger Cryonics Institute Immortalist Society Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=7739