X-Message-Number: 20276 From: "John de Rivaz" <> Subject: Letter to New Scientist, published in the 12 October issue on page 26 Date: Thu, 10 Oct 2002 14:59:11 +0100 Letter to New Scientist, published in the 12 October issue on page 26 You won't wake up From Ralph Scurlock I am surprised that, leg-pulling aside, New Scientist has allowed itself to be associated with the "science" of cryonics, based as it is on a false interpretation of current cryogenics and its medical applications (Cover, 21 September). To seek immortality through whole body freezing in liquid nitrogen after death is a science fiction fantasy; it cannot be realised in the foreseeable future for several reasons. The difference between successful cryopreservation and failure lies with size and achievable cooling rates. A single cell survives freezing if it cools so last that the entire cell freezes at once. Such cooling must take place at around 1000C per minute, even when using cryoprotectants. If cooling takes place more slowly, the water in the cell freezes first and the consequent rise in concentration of dissolved substances within the cell kills it, with no hope of later revival. Only thin sheets of human tissue, and single cells, can be cooled fast. enough. Furthermore, optimum rates of fast cooling, and re-warming, vary widely between different tissue types. In practice, cryopreservation is therefore successful only for sperm, blood, embryos, dermis, corneal tissue and the like. Even for small 3D organs such as the kidney, successful cryopreservation for transplant surgery has proved to be impracticable. Cooling to 4 ?C without freezing preserves the kidney for perhaps 48 hours, but that is all. Cryopreservation of larger organs, or the entire human body, is therefore most unlikely in the near future. Southampton ******************* My reply, emailed to today: The letter from Ralph Scurlock on page 26 of New Scientist 12 October seems to miss the point of the cryonics competition. Everyone knows these facts about cryopreservation, including cryobiologists working at cryonics organisations, who are seeking methods of minimising this damage. Cryonics is a speculation that future technology will be able to restore the damage to which Mr Scurlock refers. This damage can be described as "atoms in the wrong place". If nanotechnology (or indeed something completely different and yet unconceived) can be developed to put them back in the right place, then restoration is conceivable. Even if the chance of reanimation into good health is only small, then this small value is better than the zero value of burning or rotting your body after death. Nobody can at the present time quantify this "small value" unless they know the future. The aim of the competition has been to get people to think deeply about the issues surrounding the application of science, and not to base their opinions on tightly held beliefs or current practises. [Letters to New Scientist need a full postal address if they require publication. Usually the name and post town are published unless the writer requests anonymity.] -- Sincerely, John de Rivaz: http://www.deRivaz.com : http://www.AlecHarleyReeves.com http://www.longevity-report.com : http://www.autopsychoice.com : http://www.cryonics-europe.org http://www.porthtowan.com Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=20276