The cryonics community have been talking about the science of cryonics for more than 30 years, and so the basics have been covered many times over. Newcomers to the community may have to wait a while before hearing about some of the most basic topics, since they are discussed infrequently.
Members of the Cryonet e-mail list have recently been talking about the relevance of cases of temporary death due to drowning in cold water. In a number of instances, victims have been revived after up to an hour of clinical death and gone on to lead normal lives. This leads to a simple set of arguments that demonstrate cryonicists are on to something in their quest to defeat death through cryosuspension. This informative post is made by Charles Platt and steps through the points in a logical, helpful way:
Cold-water-drowning cases who have been revived after an hour or more without vital signs are relevant to cryonics in several ways.
1. They are living proof that postmortem brain damage can be delayed by hypothermia, especially if cooling occurs initially while the heart is still beating. This is an important factor because blood circulation can withdraw heat from the body and brain far more rapidly than surface cooling after the circulation stops. This should be reassuring to any member of a cryonics organization that cools the patient promptly after legal death has been pronounced, provided an ice bath is supplemented with cardiopulmonary support to sustain some circulation of the blood.
2. They demonstrate that cellular processes in the brain can restart spontaneously after a period of total dormancy. Consciousness returns and memories are preserved. By extension, cryopatients may be similarly revived after decades rather than hours of stasis. This is a major credibility issue for many people.
3. Resuscitation of patients after more than an hour without vital signs is a direct challenge to anyone who believes that the soul leaves the body after "death" occurs. Since revived patients do not behave like zombies, we have to assume that the soul, if it exists, is still present. Therefore, either the soul doesn't leave, or there is no soul, or the person wasn't really dead. If the drowning victim wasn't really dead, then cryopatients aren't really dead either (so long as they have been properly cryopreserved).
I have debated the relevance of cold-water-drowning cases at some length with a friend who feels that the cases are less convincing than, say, the cat-brain experiments performed by Suda. Usually the cold-water-drowning cases do not provide specific data, such as the exact time when cardiac arrest occurred. Nor was anyone able to measure brain activity or body temperature. Thus the cases are dissatisfying compared with properly controlled lab work.
On the other hand, when trying to present cryonics in a way that people find palatable, I prefer to avoid the disturbing image of isolated cat brains being reperfused with blood. I think it is much easier to talk about cute little children who are revived after being very very cold. Most journalists apparently share this outlook; the case of Brittany Eichelberger (who was rescued from a snow drift one Christmas Eve) was featured twice in People magazine, and she also appeared on TV. Thus far, the isolated cat brains have not attracted an equal amount of media attention--and if they did, I doubt it would be as positive.
Numerous cases of cold-water-drowning, followed by resuscitation, are reported each year. The history that Aschwin presented here is not unusual. You'll find a bunch of histories (some on PubMed) if you use a search string such as "cold water drowning" resuscitation.
A compelling (and acceptable) argument for the static nature of the brain is the first step to accepting that cryonics can achieve its goal - if all of the other non-trivial obstacles are overcome. Wikipedia contains an informative page on cryonics that talks about some of these issues.
Many people find cryonics a tough sell, or something that they don't want to think too hard about. I have the following to say to them: "In that case, you'd better work harder to ensure that regenerative medicine, nanomedicine and real anti-aging therapies are developed in your lifetime!"