New Life Coaxed From Dead Brains
By Janet McConnaughey, Associated Press Writer
http://dailynews.yahoo.com/h/ap/20001105/hl/cadavers_stem_cells_2.html
NEW ORLEANS, November 5, 2000 (AP) - Scientists have coaxed new life out
of dead brains.
It turns out that even cadavers can supply the incredibly versatile
brain stem
cells - master cells which can turn into different kinds of brain and
nerve cells once thought available only from fetal tissue.
So can skin. And it appears that just about every bone stem cell can be
tweaked to produce brain cells.
"It's an extraordinarily exciting field," said Ronald D.G. McKay of the
National Institute of Neurological Disorders and Stroke.
Several reports to the Society for Neuroscience seem to offer yet more
possible solutions to the ethical dilemma blocking stem cell studies
which use human fetal tissue.
But they are not yet solutions and may never be, said McKay and two
other scientists who discussed their findings at a news conference
Sunday at the society's annual meeting.
There are big differences among stem cells from embryos, from fetuses
and from adult tissue, and scientists don't really know much yet about
any of them, they said.
"We can't look in a dish at a mixed population (of cells) and say `That
is a stem cell," said Fred H. Gage of the Salk Institute at LaJolla,
Calif., where the cadaver work was done. "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 which
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. In every case
- as well as with cells from a man who died at 72 - researcher Theo
Palmer was able to get some of the cells to divide and reproduce
themselves, and to grow into different kinds of nervous system cells,
Gage said.
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. Additional work has brought that up to more than 99
percent, he
said.
Freda Miller of McGill University had been scheduled to discuss her work
turning rat skin and human scalp cells to nerve cells but could not make
it.
"That's yet another extraordinary finding," Black said.
"It may be that there is a variety of easily accessible sources that can
generate neurons," he said. If that's the
case, he said, scientists will need to find out what they all have in
common.
McKay described turning mouse embryo stem cells into brain cells which
make dopamine - the chemical neurotransmitter whose absence causes
PARKINSON'S disease.
Researchers have transplanted dopamine-producing cells derived from
fetal tissue into peoples' brains. But there is enough for only a few of
the estimated 1.2 million sufferers, and research has been slowed by
restrictions on the use of federal money for studies involving fetal
tissue.
"If you're going to use this as a routine therapy, you need access to
large numbers of cells," McKay said.
McKay said his laboratory has produced unlimited numbers of dopamine
neurons - but they produce high levels of dopamine only for a short
time.
"We need to know what kind of signals to give them'' to get the best
production, he said.
On the Net:
Society for Neuroscience: http://www.sfn.org
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Copyright © 2000 The Associated Press.
--
Judith Richards, London, Ontario, Canada
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