The goal is to induce the changes inside a living brain, eliminating the need for a transplant. Philip Schwartz, coordinator of the Brain and Tissue Bank for Developmental Disorders at Children's Hospital of Orange County, acquired most of the brains for the research, tapping hospitals along the West Coast. Although the brains were donated ahead of time by patients with incurable diseases, Schwartz said the handling of the postmortem tissues varied broadly, and that no special instructions were given to preserve the tissues. The use of cells from dead bodies seems to sidestep the ethical controversy surrounding the use of stem cells from embryos and fetuses, although some scientists argue that research is needed in all manner of stem cells. Douglas Melton, a stem-cell researcher at Harvard University, said it may turn out that adult stem cells are useful for treating some diseases, whereas embryonic or fetal cells are more effective in others.
Stem cells come in several forms.
Embryonic stem cells theoretically give rise to an entire human being. Fetal stem cells give rise to most of the essential parts of a person, but not an entire person. The Salk researchers are not calling the cells they've cultured from cadaver brains stem cells because they have not demonstrated that the cells can turn into mature brain cells in a living body. Moreover, true stem cells are capable of dividing indefinitely. Palmer said the most robust of the precursor cells from the cadavers divided 30 times, comparable to the number of times a cell taken from a live person might double.