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Science

I Wanna New Thumb 14

Posted by michael from the hitchhiking-possible-once-more dept.
joestump98 writes: "It appears that we are taking odd steps towards growing back lost tissue - a story at Yahoo! tells that 'doctors have used a patient's own body cells and a scaffold made of coral to grow back a missing portion of his thumb.' Sounds too cool!"
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I Wanna New Thumb More

I Wanna New Thumb

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  • The coral is dead and cleaned up/sterilized...
    It, as well as cadaveric(dead people) bone can be commonly used as substitute/filler bone when there are large holes that need to be filled (i.e. traumatic experience).

    The coral provides a scaphold for your bodies own osteoclasts and osteoblasts to produce new bone - but it takes a long time to do incorporate - months/years..
  • I thought coral material was alive. Even if it were just skeletal material deposits, I'd think there would be an issue of rejection to be overcome. I'm curious about how they addressed this, and whether the resulting complications would balance against the simplicity of just using the person's own tissues (i.e. a toe).
  • The coral scaffold is strictly mineral, and the material is very similar to the mineral matrix of bone. It integrates very well with the surrounding tissue, and it should be relatively unrecognizable as a xenograft after a few years at most.

    Cadaveric tissue is another thing all together. Cadaveric tissues / tissue transplants are either accopanied by the continued use of immuno-suppressive drugs for the rest of the patient's life, or the tissue has been treated (frequently with gluteraldehyde, with is similar to formaldehyde), with a "fixative." This removes all of the cellular material from the tissue, and strips most of the identifying protiens (these are what the immune system key in on) from the remaining tissue. The tissue also ends up being extremely stiff, and I don't believe that much new tissue ingrowth occurs. Commercial porcine heart-valve replacements use fixed pig heart valves sewn to a bio-compatible polymer ring for implantation. Fixed tissues require no immuno-suppressive therapy.

  • ...give this breakthrough two thumbs up!

    This is seriously too cool.

    Justin
  • Read this. [acs.org] The amount of coral used is very small, and the methods used for harvesting supposedly have little to no effect on the coral population.

    It's such a small amount that they are using, it makes very little impact. Or at least so they say...

    Scientists can already create structures that are similar to coral (at least in their porousity). An example of this would be Aerogels [connectexpress.com] which have a similar structure.

    A gel is formed, which contains a porous, solid network, and the liquid component is removed, leaving a hunk of material with an ultra-low density (comparable to that of air). Obviously this stuff couldn't be implanted into the body, but perhaps as our understanding of these processes increases we could create materials that are even more like coral.

    It's definately worth doing, if you could create something like coral, only made out of aluminum, it'd be incredibly strong and incredibly light. It might also have some other interesting properties (if the tiny spaces inside were all the same size, there might be resonance effects, etc). Overall this really won't affect the coral population though, so we have nothing to worry. It'll be years till this is even common anyways.

    Justin

    Disclaimer: I study physics, not biology. I have a friend working on a project with kindey rejection and computer analyses of statistical correlations, however my knowlege of tissue rejection is rather limited.

  • Re:Rejection? (Score:3)

    by QuantumFTL ( 197300 ) on Thursday May 17, 2001 @07:28AM (#217637)
    The coral is almost certainly dead. Rejection by the body is mostly caused by the immune system's failure to recognize surface proteins on cells from foreign tissue, thus causing an attack. Dead coral is mostly just the minerals, etc, that go into making the structure, and our not very reactive. If we can put plastic or metal into someone, putting coral into them really isn't much different. There may have been one or two things they had to do (sterelize it, possibly apply some kind of coating) but for the most part it's a lot easier than getting the body to accept something that's living.

    Justin

    (warning, I'm a physicist, not a bio major, and although i have friends working on organ rejection, there's still stuff that I wouldn't be aware of)
  • They dont use live coral they use the "dead Skelaton" of coral. The part of a coral reef that would sink ships was not the live upper coating that looked pretty it was the rock like deposits of thousands of years underneath. They use it because it is basicaly a calcium deposit in a sponge form. Pretty mutch an inert substance that they can pack the empty gaps where bone should be. The real advantage to it is what the body does. It breaks it down the same cells in the body that deal with reshaping bones after fractures and so forth actualy break down and absorb the coral replacing it with "real" bone. As for the possible enviromental effects of using coral from the see I dont theink they use "natural" coral, I believe its is grown in the lab (the only way to ensure it is sterile)
  • Recently some UK surgions have been able to re-grow a patients fingers using the old "bone-streach" technique, it cant do joints but can cirtainly improve the usability of a damaged hand, there is and article on the BBC news site Here [bbc.co.uk]
  • If I remember correctly, you have all sorts of environmentalists quite upset that coral's being destroyed by irresponsible fishers, jewelry makers, tourists...

    Using coral as a scaffold - I'm pretty sure the scientists can come up with a better idea, yes? Something that leaves the brightly-colored fish a place to play in? =)

  • Ahhh.. so it's really more of the coral _structure_, as in lots-of-dead-polyps-creating-a-sliightly-porous-so lid?

    Interesting.

    #include <disclaimer.h> - I'm a computer science person, I haven't done much of physics or bio lately. =)

  • Unfortunately, the guy now has a hole in his stomach.

    Of course, transplanting toes to replace fingers is a great alternative to this time consuming technique. But, then again, some people really appreciate the lack of hand odor involved in using the coral transplantation method.

    Dancin Santa
  • Read the article before you post:
    the practical result was an ``unstable, weak thumb,'' Drs. Vincent R. Hentz and James Chang of Stanford University in California write in an accompanying editorial. ``Tissue engineering,'' they continue, ``will truly be successful only when the body incorporates the entire tissue, and normal structure and function are restored.''

  • The scaffold was implanted where the thumb tip had been, with skin from the patient's stomach providing the finishing touch.

    I do remember some truly basic details of physiology.
    There's no "skin" on/in your stomach, your skin is an organ which covers the outside of your body.
    So now I'm wondering exactly what these "doctors" did.

  • Why coral? Beyond the enviromental and possible rejection, wouldn't titanium or another proven in body replacement work better? I have two large titanium screws in my elbow that have no rejection, are light and don't kill a natural resource...

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