Cryonics

Wouldn't that be "cryogenics?"

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Original post by superpig Wouldn't that be "cryogenics?"

Nope. Common mistake though.

I think the most accepted reason as to why it doesn't work is that, when water crystalizes (freezes), it forms a rather sparse structure and this expansion ruptures all of the cells in the body. Presumeably, though, if you were to freeze some biological material quickly enough you wouldn't have this problem, as crystals do not form when a liquid is frozen extremely quickly. You'd also have to come up with a good way of thawing the material.

In 9th grade I did an experiment in which I dipped some spider plants in liquid nitrogen, then thawing them in hot water (110 degrees F, I think). Overall about 10% of the cells seemed to remain intact under a microscope, as opposed to the complete mush (no cell structure at all) that they turned into when put in a freezer. For some reason two of the plants seemed to have most of their cells still intact (I'm not sure why this was only true for two of them), and when re-planted they actually started to grow new leaves before dying several days later. That surprised me quite a bit.

The page linked to actually talks about that.

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Original post by cowsarenotevil In 9th grade I did an experiment in which I dipped some spider plants in liquid nitrogen, then thawing them in hot water (110 degrees F, I think). Overall about 10% of the cells seemed to remain intact under a microscope, as opposed to the complete mush (no cell structure at all) that they turned into when put in a freezer. For some reason two of the plants seemed to have most of their cells still intact (I'm not sure why this was only true for two of them), and when re-planted they actually started to grow new leaves before dying several days later. That surprised me quite a bit.

That's really interesting -- aren't plant cells quite a bit simpler than animal cells though?

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Original post by Ravuya Quote: Original post by cowsarenotevil In 9th grade I did an experiment in which I dipped some spider plants in liquid nitrogen, then thawing them in hot water (110 degrees F, I think). Overall about 10% of the cells seemed to remain intact under a microscope, as opposed to the complete mush (no cell structure at all) that they turned into when put in a freezer. For some reason two of the plants seemed to have most of their cells still intact (I'm not sure why this was only true for two of them), and when re-planted they actually started to grow new leaves before dying several days later. That surprised me quite a bit. That's really interesting -- aren't plant cells quite a bit simpler than animal cells though?

I don't think that would make much of a difference. Plant cells are fairly complex too. What could, however, pose problems, is that animal cells within onr organism are alot more varied in nature (hundreds of types of specialized cells). Some cells, like neurons for example, are extremely fragile.

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Original post by Max_Payne I don't think that would make much of a difference. Plant cells are fairly complex too. What could, however, pose problems, is that animal cells within onr organism are alot more varied in nature (hundreds of types of specialized cells). Some cells, like neurons for example, are extremely fragile.

Remember that plant cells are a series of adjacent, well, cells (meaning that if there's equal pressure in all of them, they're not likely to "explode" as each wall that would burst outward is theoretically balanced by the cell that it's adjacent to trying to do the same thing), and they also have hard walls rather than thin membranes. So plants probably far, far less likely to get killed by freezing, but it doesn't seem like their simplicity is what causes that.

hmmm... aparently you haven't heard that scientist froze a dog and brought him back to life. they replaced his blood with a saline solution and froze him for quite some time. then unfroze him and replaced his blood.
and cryonics is the study of freezing the diseased body of a human for later time, while cryogenics is the study of phenomena that occur at low temperatures. so you cna use either term.

I believe there's some species of frog that actually freeze solid during winter, then thaw again during the summer. There's something funky going on in their bloodwork that prevents the freezing water from destroying their cells. I saw it on a documentary ages ago so I can't remember any of the details.

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Original post by Nemesis2k2 I believe there's some species of frog that actually freeze solid during winter, then thaw again during the summer. There's something funky going on in their bloodwork that prevents the freezing water from destroying their cells. I saw it on a documentary ages ago so I can't remember any of the details.

I think its basically the same thing Jarrod1937 mentioned (though I'm not sure if his anecdote is true): they have a sort of antifreeze in their blood that stops it from actually freezing completely.

Been doing a bit of reading.... apparently cryonics uses "cryopreservatives" (essentially antifreeze) to prevent freezing and crystallization.

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Original post by Sneftel Been doing a bit of reading.... apparently cryonics uses "cryopreservatives" (essentially antifreeze) to prevent freezing and crystallization.

That's one way, but it's not the only method people try for freezing people. Like I mentioned, simply freezing things very quickly is one of the other methods.

And some of them just freeze you and claim that by the time you're thawed modern medicine will be able to repair the damage [headshake]

I have not read anything about this, but here is a major reason why I think it won't be possible:

Damage to molecules (notably enzymes and DNA) which are necessary for life happens all the time due to free radicals caused by chemicals, radiation etc. Normally the cell contains many clever chemical processes to repair this damage.

Freezing people will suspend the processes which repair the damage, but the causes of the damage will continue (albeit perhaps at a reduced rate).

Therefore, imagine, if you're frozen and brought back "to life", 100 years later, it would be as if you've just been hit with 100 years worth of background gamma radiation in one second - i.e. you'd instantly die of radiation poisoning.

This is entirely independent of all other issues, e.g. ice crystalisation.

So perhaps it is possible to cryonically preserve people (more realistically organs) for short periods, for instance while being transported or having donors found, but waking up 100 years later seems unlikely.

Mark

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Original post by markr I have not read anything about this, but here is a major reason why I think it won't be possible: Damage to molecules (notably enzymes and DNA) which are necessary for life happens all the time due to free radicals caused by chemicals, radiation etc. Normally the cell contains many clever chemical processes to repair this damage. Freezing people will suspend the processes which repair the damage, but the causes of the damage will continue (albeit perhaps at a reduced rate). Therefore, imagine, if you're frozen and brought back "to life", 100 years later, it would be as if you've just been hit with 100 years worth of background gamma radiation in one second - i.e. you'd instantly die of radiation poisoning. This is entirely independent of all other issues, e.g. ice crystalisation. So perhaps it is possible to cryonically preserve people (more realistically organs) for short periods, for instance while being transported or having donors found, but waking up 100 years later seems unlikely. Mark

but when you freeze a human you could simply block the body from all environmental effects like radiation, pollution...etc and then when the body is frozen along with all the shielding no more damage from free radicals should occur. it is from my understanding that free radicals only cause damage from atom to atom in 1 cell only and do not pass the effect onto other nearby cells, but i could be wrong i guess.

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Original post by markr I have not read anything about this, but here is a major reason why I think it won't be possible: Damage to molecules (notably enzymes and DNA) which are necessary for life happens all the time due to free radicals caused by chemicals, radiation etc.

With your body frozen, the normal chemical reactions which produce free radicals will not occur. Radiation can obviously be shielded against.

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Normally the cell contains many clever chemical processes to repair this damage. Freezing people will suspend the processes which repair the damage, but the causes of the damage will continue (albeit perhaps at a reduced rate).

This is unlikely.

Not only will free radical creation occur at a greatly reduced rate, they will also suffer from reduced mobility: because the body is frozen, it will be harder for a free radical to get to somewhere it can do a lot of harm, and should it get there it will be harder for it to actually start a reaction.

The existing free radicals at the time of death can be purged, to some extent, using a powerful antioxidant, and unlike antioxidants you take whilst alive, it doesn't matter if it's powerful enough to kill you.

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Therefore, imagine, if you're frozen and brought back "to life", 100 years later, it would be as if you've just been hit with 100 years worth of background gamma radiation in one second - i.e. you'd instantly die of radiation poisoning.

Even without shielding, the background radiation accrued over 100 years is only around 20 rem. Potentially lethal doses start at around 200 rem. So I don't think radiation poisoning is likely to be a problem, unless perhaps cryopreserved patients are stored in a nuclear reactor core.