An Outsider's Overview of Cryonics
If you read the whole thing, this outsider's view of cryonics at CMAJ illustrates a few of the subtle prejudices held in the medical and scientific community in the course of trying to be objective: "cryonics - the practice of preserving a legally dead person at a temperature far below freezing in hopes of someday being revived and rejuvenated after advances in science have provided a cure for their ailment. The appeal is self-evident, enthusiasts say. 'It certainly offers an opportunity, although remote and probably speculative, as an ambulance to the future so to speak. If I die from something that is not preventable today, maybe future technology will offer the means of reviving me, figuring out the condition I have and fixing it.' Yet, however appealing the notion of a second life may be, the number of people who've actually been frozen is miniscule: about 250, according to the Cryonics Institute, a cryonics services provider located in a regional township of the state of Michigan. ... But far more people appear interested in being frozen. Membership in the two biggest cryonics providers in the United States - the Cryonics Institute and the Alcor Life Extension Foundation in Scottsdale, Arizona - is close to 2000. ... The cryonics process involves draining a patient's fluids and replacing them with a vitrification solution, essentially a preservative cocktail of cryoprotectant chemicals such as dimethylsulfoxide, ethylene glycol, propylene glycol and glycerol that are believed to prevent ice crystal formation and reduce the extent of tissue damage that occurs after flesh is frozen. The corpse is allowed to cool and then dropped into liquid nitrogen for indefinite preservation at a brisk -196°C. Or as Ben Best, president of the Cryonics Institute, writes in an email 'the perfusion process involves replacing body water in cells, not just blood in the blood stream. By perfusing vitrification solution into the blood stream, there is an exchange of vitrification solution for water. Water is removed from the body (and tissues) as vitrification solution replaces it by the diffusion process. With vitrification solution in brain tissue (especially) there should be no ice formation whatsoever. The flesh is therefore vitrified, not frozen (freezing means ice). The patient is cooled under a computer controlled cooling box to liquid nitrogen temperature, not simply 'dropped' in liquid nitrogen.'"
Link: http://www.cmaj.ca/site/earlyreleases/19mar12_spending-eternity-in-liquid-nitrogen.xhtml