| | Scientific American: The Stem Cell Challenge (Site not responding. Last check: 2007-09-09) |
 | | For scientists to be able to share results and gauge the success of techniques for controlling stem cell behavior, we must first know that the cells we are studying actually possess the ability to serve as the source, or "stem," of a variety of cell types while themselves remaining in a generic state of potential. |
 | | ES cells and their derivatives carry the same likelihood of immune rejection as a transplanted organ because, like all cells, they carry the surface proteins, or antigens, by which the immune system recognizes invaders. |
 | | As is true of embryonic cells, so little is understood about the factors that may control the adult stem cells' fate that we do not yet know whether extensive time spent in culture could harm their ability to restore tissues in patients. |
| www.sciam.com /print_version.cfm?articleID=000DFA43-04B1-10AA-84B183414B7F0000 (3323 words) |