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Stem Cells - What are stem cells and what are they used for

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Stem Cells - What are stem cells and what are they used for Powered By Docstoc
					Question: What are stem cells and what are they used for?
Taken from: www.howstuffworks.com


Stem cells are unprogrammed cells in the human body that can be described as "shape
shifters." These cells have the ability to change into other types of cells. Stem cells are
at the center of a new field of science called regenerative medicine. Because stem
cells can become bone, muscle, cartilage and other specialized types of cells, they have
the potential to treat many diseases, including Parkinson's, Alzheimer's, diabetes and
cancer. Eventually, they may also be used to regenerate organs, reducing the need for
organ transplants and related surgeries.

"Stem cells are like little kids who, when they grow up, can enter a variety of
professions," Dr. Marc Hedrick of the UCLA School of Medicine says. "A child
might become a fireman, a doctor or a plumber, depending on the influences in their
life -- or environment. In the same way, these stem cells can become many tissues by
making certain changes in their environment."

Stem cells can typically be broken into four types:

      Embryonic stem cells - Stem cells taken from human embryos
      Fetal stem cells- Stem cells taken from aborted fetal tissue
      Umbilical stem cells - Stem cells take from umbilical cords
      Adult stem cells - Stem cells taken from adult tissue

Embryonic and fetal stem cells have the potential to morph into a greater variety of
cells than adult stem cells do.

Prior to being transplanted into a person's tissue to begin regeneration of that tissue,
stem cells have to go through differentiation. Differentiation is the process by which
scientists pre-specialize the stem cells, almost like preprogramming the stem cells to
become specific cells. These cells are then injected into the area of the body being
targeted for tissue regeneration. When stem cells come into contact with growth
chemicals in the body, the chemicals program the stem cells to grow into the tissue
surrounding it.

Stem cells are already being used to treat leukemia and some joint repairs. For
example, a bone-marrow transplant is accomplished by injecting stem cells from a
donor into the bloodstream of the patient. Stem cells from bone marrow also have the
ability to repair the liver. Researchers are studying stem cells to find out if they could
correct brain damage resulting from Parkinson's disease.

The next step will be to learn what influences stem cells to change into particular types
of cells. Once that's known, it will be possible to grow cells that perfectly match those
of the patients.

				
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