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Biotech / Medical : Geron Corp. -- Ignore unavailable to you. Want to Upgrade?

To: Coolbreeze who wrote (1257)	11/6/1998 10:25:00 PM
From: flickerful	Read Replies (1) \| Respond to of 3576

Teams finally culture embryonic stem cells November 5, 1998 For 17 years, researchers raced to be the first to sustainably culture human embryonic stem cells. These cells are the raw material from which all human cells develop. Being able to grow them would have profound effects on medicine by allowing doctors to grow virtually any cell in the body from scratch. Now scientists at the University of Wisconsin at Madison have reported in the journal Science the first successful derivation and prolonged culture of these cells. At the same time, a team from John Hopkins published an article in the Proceedings of the National Academy of Sciences describing the same success, reached using a slightly different method. Although he cautions that a great deal of work needs to be done before the advances can lead to human therapies, Dr. James A. Thomson thinks in the long run it will revolutionize transplantation medicine. Thomson is a UW-Madison developmental biologist and lead author on the study, and thinks the first application of human stem cell technology will be to quickly screen hundreds of thousands of chemicals for their potential as new medicines. By testing chemicals on pure populations of specific differentiated cells, for example kidney cells or marrow cells, researchers could sort out new medicines and anticipate problems. But the real excitement comes from the transplantation possibilities of stem cell technology. Because the cells do not age, they could theoretically be used to generate an endless supply of tissues for transplantation. Embryonic stem cells could also be used to augment failing cells in certain organs, as in the case of brain cells responsible for Parkinson's disease or pancreas cells that fail to produce insulin. The cells can potentially be grown in very large supplies, solving the problem of limited donor supplies, and they can be genetically engineered in a laboratory to avoid the immune response that mars present transplants. In the experiments, which U.S. federal funds are prohibited from supporting, the researchers at UW used donated human blastocytes. These precursors of fetuses are groups of roughly 140 cells that develop several days after fertilization, and take the form of a hollow ball. They were taken from laboratory dishes that were part of fertility procedures where couples who had difficulty having babies needed several embryos for successful transplantation. These were the leftovers, and were donated with the informed and written consent of the donors. Embryonic stem cell colonies sometimes include a core of undifferentiated cells surrounded by a layer of differentiated ones. The researchers developed five separate cell lines, watching as the cells grew from undifferentiated stem cells to become the three primary germ lines that make up the body -- the endoderm, the mesoderm, and the ectoderm. The cells then changed themselves into groups of cartilage, bone, muscle, neural and gut cells. The insights they offer are a window into the developmental processes that create full-grown living animals, processes that can't be observed in living embryos and are still poorly understood. Directing the stem cells to become specific types of cells is still beyond the reach of the new technology, and needs to be understood before many clinical applications can see the light of day. Another obstacle is engineering the transplantable cells to avoid triggering the immune reaction of their new host body. But it's certain that those are problems that biotechnology companies like Geron, the Menlo Park, California-based outfit that supported both the John Hopkins and University of Wisconsin teams, is looking forward to tackling. exn.net