X-Message-Number: 15119 Date: Sat, 16 Dec 2000 07:26:50 -0500 (EST) From: Ben Best <> Subject: Re: An assist to CPAs and Ice-Blockers (Erratum) On Sat, 16 Dec 2000, Ben Best wrote: > CryoProtective Agents (CPAs) and Ice-Blockers can prevent > ice-formation and promote vitrification. But Ice-Blockers > typically do not cross cell membranes. And CPAs are always > challenging to perfuse/diffuse because both their toxicity and > viscosity vary inversely with temperature. In my efforts at pompous simplicity, I misstated the facts. CPA viscosity does vary inversely with temperature -- so that the lower the temperature of introduction, the more difficult it is to get the stuff to perfuse through blood vessels and diffuse into cells. However, CPA toxicity tends to vary DIRECTLY (not inversely) with temperature -- meaning that it is much less toxic when introduced at lower temperatures. Therein lies the trade-off: how to introduce the CPAs at a high enough temperature to minimize viscosity, but at a low enough temperature to minimize toxicity. Also, by the time genetic engineering is sophisticated enough to modify genes so as to manufacture the "designer" insulin-receptor of my fantasy, genetic engineering should also be able to add genes for production of ice-blocker proteins in the cells of mammals. If these proteins are innocuous enough, they could be present at all times in the cell without much harm. After all, if cells can function adequately with large amounts of lipofuscin, they should be able to tolerate some otherwise non-functional ice-blocker proteins -- which don't need to be present in high quantities to be effective. This is an advantage over my proposed insulin receptor in that there is no time-critical procedure to be applied in a cryonics emergency -- although it is still time-critical that cooling occur rapidly after deanimation. -- Ben -------------------------------------------- Ben Best () http://www.benbest.com/ ICQ -- http://www.mirabilis.com/20636141 Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=15119