Hi, folks...
I was directed to this thread from a post over at Cold Filter. I'm the moderator over there. Yes, I'm an advocate of cryonics as well, but cryonics isn't my god or my religion. I don't have faith in it. I view it as a potentially life-saving technology which is still in its early experimental phase. To me, it's worth being a test subject, a guinea pig, simply because it beats the currently available alternatives. Let me also add that I agree that there should be some sort of regulation, but that it should
not be done from the perspective that cryonics is a pseudoscience.
Many of the critiques of the science behind cryonics posted in this thread are based on misconceptions or outdated limitations that have been largely overcome by scientific advancement. For instance, the "mushy frozen strawberry" analogy. This may apply to a brain dumped in the freezer, but that has little resemblance to the washout procedure and cool-down process cryonics has used. More importantly, in recent years cryonicists have started using solutions designed to prevent crystalization, or ice formation, which is the primary cause of damage to tissues. In a chemical reaction called vitrification, tissues become glass-like rather than freezing in the conventional sense. Vitrification is now commonly used in organ preservation research.
Good preservation of rat brain tissue has been demonstrated and published in Cryobiology, the abstract is available in PubMed:
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www.ncbi.nlm.nih.gov]
The main hurdle to overcome is the level of toxicity in these vitrification solutions. Some say that this will be a minor problem by the time revival is feasible, but most cryonicists see it as a major issue. Researchers continue to work on it.
Another objection I saw in this thread was that people resuscitated after total cessation of brain activity would lose their memories or identity. Below are some quotes that suggest that this is misguided. As you'll see, the first one is from a widely used medical textbook:
"We know that secondary memory does not depend on continued activity of the nervous system, because the brain can be totally inactivated by cooling, by general anesthesia, by hypoxia, by ischemia, or by any method, and yet secondary memories that have been previously stored are still retained when the brain becomes active once again. Therefore, secondary memory must result from some actual alterations of the synapses, either physical or chemical." - Page 658, Textbook of Medical Physiology by Arthur C. Guyton (W.B. Saunders Company, Philadelphia, 1986).
"Clinical medicine is now able to "turn off" people for more than an hour with no heartbeat or brain activity for certain surgical procedures. Scientists are on the verge of being able to preserve individual organs indefinitely by using a new technology called vitrification. Brain electrical activity has been detected in animals rewarmed after seven years of frozen storage. Could human life be preserved in an arrested state for years or decades instead of hours? The prospects are still distant, but some people are already betting that current preservation technology may be good enough to be reversible in the future. Whether they are correct is a legitimate scientific question."- Brian Wowk PhD. Medical Time Travel, 2004.
"A large dose of pentobarbital, a barbiturate, or propofol, a sedative, is usually used to induce the coma. Monitored with an EEG, the brain shows no activity whatever. 'The brain waves go flat,' [Dr.] Mayer said [Columbia U Med Center]. 'Patients look like they're dead. There's no reaction to any pinch, no pupil reaction, nothing.'"- San Diego Union -Tribune, Jan.25,2006.
"Thomas Donaldson says that brain waves of supercooled small animals have been measured, and there are none, even though the animals still have their memories after they are rewarmed. He cites AU Smith, ed. BIOLOGICAL EFFECTS OF FREEZING AND SUPERCOOLING, London, 1961; article by Aubrey Smith herself, "Revival of mammals from body temperatures below zero", pp. 304-368."- Timothy Freeman, 1 Nov 1998.
Along these lines, another common concern is that--even if someone is plunged immediately into an ice-bath for cooling--there may be a few minutes of warm ischemia or oxygen deprivation leading to global brain death. This isn't the case. Mainstream medicine has broken through the 5 minute brain resuscitation barrier in experimental models going out to 13 minutes of warm cardiac arrest:
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www.ncbi.nlm.nih.gov]
Cats have been recovered after ONE HOUR of warm cardiac arrest with only loss of hippocampal and striatal tissue:
[
www.ncbi.nlm.nih.gov]
Living neurons have been cultured at 4 hours:
[
www.ncbi.nlm.nih.gov]
8 hours:
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www.ncbi.nlm.nih.gov]
The issue has been raised in mainstream medical literature:
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ccforum.com]
Excerpted at:
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www.alcor.org]
Here's a quote from a mainstream medical website:
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nhnscr.org]
"It is quite clear that clinically defined death, which in most states is simply the cessation of cardiac and respiratory activity, does not mean that all of the cells of the body have died. It simply means that the cells required to maintain/sustain life, namely, cardiac muscle cells and diaphragmatic muscle cells no longer function adequately."
Thank you for reading,
Jonathan