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J-Man
2001-Dec-10, 06:53 PM
First I want to say that I enjoyed your interview Phil. I am always impressed with your desire to correct the misconceptions people hold with regards to science.

That said, I think you may have made a mistake in your interview. You mentioned something about it not being possible to freeze a person (and succesfully reheat them living) because of the high concentration of liquid water in our cells (a la Austin Powers.) Water expands as it freezes. You are correct in two of those three ideas... water expands and humans have a high concentration of water. However that does not necessarily mean that a frozen cell will be destroyed. Biologists and doctors often freeze and unfreeze cells sucessfully. Examples are fish and other amphibians, blood, blood plasma, simple organs, etc. I believe cell membranes are often malliable enough to absorb the expansion of water... think of a balloon with water in it. Yes, the balloon will be mostly water; yes, the water will expand when frozen, but the balloon surface will expand with the water and not necessarily break (depending on the balloon material of course.)

By the way... I realize we don't have the technology, at the moment, to succesfully freeze and unfreeze a living human, but it certainly is not impossible nor inconceivable.

Anybody else agree with me, or am I comparing applefish to orangehumans?

Donnie B.
2001-Dec-11, 12:20 AM
There are some fish that can survive temperatures lower than the normal freezing point of water. They have a natural antifreeze in their tissues. They don't actually survive total freezing and thawing.

Likewise, human organs cannot be frozen solid and then reused. They are kept very cold, near freezing, to slow the metabolic processes in the absence of circulation, but not frozen.

There may be some living things that can survive being frozen solid. But humans are not among them. The BA was right; there's just too much cell damage. However, in the future, there may be technologies that would allow humans to survive being held very near freezing, or perhaps even below 0 degrees C if the "natural antifreeze" can be duplicated (say, by genetic engineering). I'm not sure I'd care to volunteer for that program...

Mr. X
2001-Dec-12, 02:21 AM
I'm with you, in time it will probably be possible to freeze and thaw a full living human, with adequate preparation prior to freezing.

I think the real problem lies not in the expansion of water, but in its crystallisation (spelling?). The sharp crystals permanently damage the plasmic membrane (tear). However, if you could find a way to get a non-toxic chemical that prevents water not from freezing but from forming crystals inside every cell, I think you would win that battle, and probably the whole war singlehandedly.

I think the membrane is strong enough to withstand the water's larger volume. I don't know if the nucleus and other "organites" (bad translation, I know) would survive being crushed if the larger volume was to be held inside the cell. Well, there's only one way to find out!

On the animal front, I've heard of an insect (not really an animal, no need to nitpick) that made the news around 2, maybe 3 years back, some sort of worm found living in extremely cold conditions, and was actually able to survive being thoroughly frosted. If only I could find those old news. I think the explanation was that his cell's membranes were either unusually strong or that same sort of thing I just said, one of the two, I don't remember.

J-Man
2001-Dec-12, 06:22 PM
Donnie B says: "There are some fish that can survive temperatures lower than the normal freezing point of water. They have a natural antifreeze in their tissues. They don't actually survive total freezing and thawing.

Likewise, human organs cannot be frozen solid and then reused. They are kept very cold, near freezing, to slow the metabolic processes in the absence of circulation, but not frozen."

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I sit corrected... I assumed when I heard and read "frozen" they actually meant frozen... so much for ***-u-me-ing.

But I still think that it is not impossible. It might require a chemical solution (type of antifreeze or simply extra atoms to change the HCP chrystal structure to a less damaging, nonexpanding, chrystal) to be injected and spread through the body's cells. Or possibly a fast thermal controller so that the cells are kept near freezing and if an area goes below a threshold it is warmed slightly.
Hard to do - absolutly, but not impossible. There are certainly avenues to explore.