And it appears that just about every bone stem cell can be tweaked to produce brain cells. Several reports to the Society for Neuroscience seem to offer yet more possible solutions to the ethical dilemma of stem-cell studies that use human fetal tissue. Stem cells may carry the potential to treat a range of diseases, including diabetes and neurological disorders such as Alzheimer's and Parkinson's. But they are not yet solutions, and may never be, said McKay and two other scientists who discussed their findings at a news conference today at the society's annual meeting. There are big differences among stem cells from embryos, fetuses and adult tissue, and scientists don't know much about any of them, they said.
Different people have different ideas.
The main definitions, said Ira Black of the University of Medicine and Dentistry of New Jersey, are that stem cells are immature cells that can duplicate themselves and grow into different kinds of mature cells. Gage's research used bits of tissue taken soon after death from children and young adults who had died of various neurological diseases. His lab got the tissue 10 hours to three days after death. Black grew brain cells from cells taken from bone marrow, where they ordinarily would have created bone, cartilage, muscle, tendon and fat cells. He previously reported that he and his colleagues had been able to turn 80 percent of the bone marrow cells taken from rats and humans into nerve cells.