Possible treatments |
Current treatmentsFor over 30 years, bone marrow stem cells have been used to treat cancer patients with conditions such as leukemia and lymphoma. These are detroyed in some chemotherapy treatments, but if they are removed before the process and then reinjected, the cells produce large amounts of red and white blood cells, to keep the body healthy and help to fight infection. Since the 1980s stem cells have been taken from the blood instead of the bone-marrow, making the procedure safer for older people. Although normally scarce, the number of 'Peripheral blood cells' can be increased by a course of drugs, which release the stem cells from the bone-marrow. These are removed before chemotherapy, which kills most of them, and then re-injected. Potential treatments |
Adult stem cells may be even more versatile than this. Researchers at the New York University School of Medicine have extracted stem cells from the bone-marrow of mice which are they say are pluripotent. Turning one type of stem cell in to another is called transdifferentiation.
As well as having the largest medical potential, they are also the most controversial type of stem cell because their utilization involves the destruction of human embryos. Some people believe that these embryos are human beings, and therefore destroying them for any reason is effectively murder. This belief is also the basis for 'Pro-life' opposition to abortion. Many scientists defend the destruction of embryos citing all the medical benefits that it is possible to achieve with them, and saying that many would have been destroyed anyway. 'Pro-life' groups respond that it would be possible to achieve the same benefits from the use of adult stem cells - although most scientists agree that we are further from using these in the same way hoped for embryonic stem cells.
Another controversy in the use of embryonic stem cells is the use of [theraputic cloning]?. This involves the cloning of early embryos from which stem cells are harvested, providing a larger source of the cells. Many see this as encouraging human cloning, which they think could be dangerous or unethical.
For over 30 years, bone marrow stem cells have been used to treat cancer patients with conditions such as leukemia and lymphoma. These are detroyed in some chemotherapy treatments, but if they are removed before the process and then reinjected, the cells produce large amounts of red and white blood cells, to keep the body healthy and help to fight infection.
Since the 1980s stem cells have been taken from the blood instead of the bone-marrow, making the procedure safer for older people. Although normally scarce, the number of 'Peripheral blood cells' can be increased by a course of drugs, which release the stem cells from the bone-marrow. These are removed before chemotherapy, which kills most of them, and then re-injected.
Stem cells are also apparently able to repair muscle damaged after [heart attack]?s. Heart attacks are due to the coronary artery being blocked, starving tissue of oxygen and nutrients. Days after the attack is over, the cells try to 'remodel' themselves so they can pump harder. However, because of the decreased blood flow this attempt is futile and results even more muscle cells to weaken and die. Researchers at Columbia-Presbyterian? found that injecting bone-marrow stem cells in to mice which had had heart attacks induced in them resulted in an improvement of 33 per cent in the functioning of the heart. The damaged tissue had regrown by 68 per cent. Clinical trials in humans are hoped for by 2003.
In fact, useful sources of adult stem cells are being found in organs all over the body. Research at McGill University in Montreal have extracted stem cells from skin able to differentiate in to many types of tissue including neurones, smooth muscle cells and fat-cells. These were found in 'dermis' - a layer of tissue beneath the skin.
In the same way that organs can be transplanted from cadavers researchers at the [Salk Insitute]? in California have found that these could be used as a source of stem cells as well. Taking stem cells from the brains of corpses they were able to coax them in to dividing in to valuable neurons. However whether they will function correctly when used in treatment has not yet been determined.
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