We need embryonic stem cell research.....it may be the "magic bullet".............................The ultimate spare part.
Embryonic stem cells are found in early stages of the embryo, after the egg is fertilized and has begun dividing, but before the mass of cells attaches itself to the wall of the uterus. Eventually they differentiate into the various cell types in the body, and disappear. "The nature of embryonic stem cells," says Thomson, "is to quickly develop into other types of cells." The fact that, in nature, embryonic stem cells are ephemeral makes Thomson's achievement singular: What he's done is to capture the cells in their undifferentiated state and keep them in that state in culture. The next step, he says, is to figure out how to direct them to become specific types of cells which would allow scientists to grow an almost unlimited supply of cells for transplant and other aspects of medicine and biology.
Gearhart says, "We clearly had evidence for human stem cells. They've been able to differentiate into several tissue types in a dish." Post-doctoral fellow Michael Shamblott collaborated on the research.
Gearhart says he's confirmed the presence of hematopoietic cells -- cells that can form any blood cell -- among the descendants of the embryonic stem cells. Since the stem cells are the ancestors of all blood cells -- red, white and pink (just kidding) -- one of their first clinical uses could be restoring the blood system after certain cancer treatments. And since blood stem cells can form the CD-4 immune cells that are killed by HIV, the AIDS virus, doctors might be able to replace these essential disease-fighting cells for AIDS patients.
Also on the horizon is a kind of "universal" human donor cell, an in-stock item that could serve as raw material for new liver cells, say, or new spinal cord cells. These donor cells would have to be genetically engineered so they didn't form the cell-surface molecules that incite attack by the recipient's immune system. Under the best of circumstances, Gearhart's "wild guess" is that clinical experiments with stem cells are at least seven years away.
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