liz_marcs (liz_marcs) wrote,

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Science Tuesday!

Interesting article about stem cell research that actually takes a look at several lines of inquiry.

The politics are limited only in how it impacts research. It's nice to read a clear and concise summary. Not as "clean" as Ron Reagan would like us to believe; but nowhere near as dirty as some parties want us to believe.

This one covers embryonic stem cells; adult stem cells; and murine (mice) stem cells:

Stem Cells: Promise, in Search of Results

August 24, 2004

BOSTON - At three laboratories here, separated by a taxi
ride of no more than 10 or 15 minutes, the world of stem
cell research can be captured in all its complexity,
promise and diversity.

One of the labs focuses on cells taken from human embryos,
another on cells from mice and fish, and a third from stem
cells that have mysteriously survived in the adult body
long after their original mission is over.

But while the work here and elsewhere has touched off a
debate reaching into the presidential campaign, a tour
through these labs shows that the progress of research is
both greater and less than it seems from a distance.

One idea, the focus of about half the nation's stem cell
research, involves studying stem cells that are naturally
present in adults. Researchers have found such cells in a
variety of tissues and organs and say they seem to be a
part of the body's normal repair mechanism. There are no
ethical issues in studying these cells, but the problem is
in putting them to work to treat diseases. So far, no one
has succeeded.

The other line of research, with stem cells from embryos,
has a different obstacle. Although, in theory, the cells
could be coaxed into developing into any of the body's
specialized cells, so far scientists are still working on
ways to direct their growth in the laboratory and they have
not yet effectively cured diseases, even in animals.

The most progress with embryonic stem cells is in mice,
where one group of researchers directed the cells to grow
into a variety of blood cells, but not yet the ones they
want. Another group directed mouse stem cells to grow into
nerve cells and tried to use them to treat Parkinson's
disease in mice. The nerve cells produced the missing
chemical, dopamine, but not enough to cure the disease.

As the two lines of research proceed along parallel paths,
researchers say it is far too soon to bet on which, if
either, will yield cures first. "It's not either-or," said
Dr. Diana Bianchi, chief of the division of medical
genetics at Tufts New England Medical Center in Boston.

At the medical center, Dr. Bianchi says, her foray into the
world of stem cell research involved a decade of
discoveries so unexpected that despite her stellar
reputation, colleagues at first looked askance.

Dr. Bianchi, who works in a lab stretched out along a
narrow corridor of an old building that was once a garment
factory, stumbled into the field when she was trying to
find a new method of prenatal diagnosis.

She knew that a few fetal cells enter a woman's blood
during pregnancy and hoped to extract those cells for
prenatal diagnosis. That proved too difficult because there
are so few fetal cells in maternal blood.

But then she discovered that the fetal cells do not
disappear when a pregnancy ends. Instead, they remain in a
woman's body for decades, perhaps indefinitely. And if a
woman's tissues or organs are injured, fetal cells from her
baby migrate there, divide and turn into the needed cell
type, be it thyroid or liver, intestine or gallbladder,
cervix or spleen.

She and her colleagues find fetal cells by looking for male
cells in tissues and organs of women who have been pregnant
with boys and showing that the cells' DNA matches that of
the women's sons or, if the women had abortions, their male
fetuses. (Cells from female fetuses also enter a woman's
body, but it is quicker and easier to find the male cells
by looking for cells with a Y chromosome, Dr. Bianchi

One woman, for example had hepatitis C, a viral infection.
But when her liver repaired itself, it used cells that were
not her own.

"Her entire liver was repopulated with male cells," Dr.
Bianchi said.

Such findings astonished even Dr. Bianchi. But now, with
publications in leading journals, including, last month,
The Journal of the American Medical Association, few doubt

In theory, fetal cells lurking in a woman's body are the
equivalent of a new source of stem cells and could be
stimulated to treat diseases. But, Dr. Bianchi says, she
does not yet know for sure that the cells are stem cells -
she must isolate them and prove they can turn into any of
the body's specialized cells - nor where the cells reside,
or how, short of injury, to spur them to action.

Using Mice and Fish, for Now

A short distance away, Dr.
Leonard Zon, the chief of stem cell research at Children's
Hospital, and his colleague Dr. George Q. Daley are working
with stem cells from embryos, using mice and zebra fish for
now. They want to learn how to transform the stem cells
into immature blood cells that will divide and replenish

Then, if they can apply their work to human embryonic stem
cells, they want to use the cells instead of bone marrow
transplants to treat patients with genetic disorders like
sickle cell anemia, and inborn disorders of the immune

Dr. Zon treats children with these diseases, most of whom
do not have a relative whose cells match theirs closely
enough to serve as a bone marrow donor. He urgently wants
to help.

But he is not there yet. So far, in research that stem cell
investigators say is among the most promising in the field,
Dr. Zon and Dr. Daley have turned mouse embryonic stem
cells into mouse blood cells. Those blood cells, however,
are more mature than the ones they need, a particular type
of early blood cells that can repopulate a patient's bone
marrow and survive indefinitely. Ones that are more mature
live out their lifespans and die within weeks.

They are also working with human embryonic stem cells,
venturing into the most controversial area of stem cell
work. Human embryonic stem cells are derived from human
embryos, about a week old, and the only way to get the stem
cells is to destroy the embryos.

Some human stem cells came from embryos that were donated
by couples at fertility labs who had embryos left over
after they decided their families were complete. Others
came from embryos that were created to obtain stem cells;
researchers paid women to donate eggs, fertilized them and
let them grow to the stage where stem cells could be

The federal government has agreed to pay for research with
human stem cells, but only for work with 22 lines; each
line is the progeny of a single embryo. That restriction
dates from Aug. 9, 2001, when President Bush issued a
directive saying the government would pay for research, but
only with cell lines created before that date.

Dr. James F. Battey, director of the National Institute on
Deafness and Other Communication Disorders and chairman of
the National Institute of Health's stem cell task force,
said scientists were free to study other stem cell lines if
they used private money. He understands the researchers'
complaints that it would be better if the government paid
for work on more lines, but, he said, as far as the federal
government is concerned, "the argument isn't solely about

"What the president has already said on multiple occasions
is that he is committed to the notion that taxpayers' money
should not be used to encourage the destruction of human
embryos," Dr. Battey said. "This is a White House policy."

And, he said, "it is not based solely on the needs of the
scientific community."

But Dr. Zon said being able to work on more human stem cell
lines could help the research.

"When you are trying to do research, you look for every
advantage you can," he said. "Some embryonic stem cell
lines make particular tissues better than others."

Some, for example, might more easily turn into blood cells,
and others might more easily grow into nerve cells, but
there is no way to know whether there is a better stem cell
line for a particular cell type without trying as many as
possible, Dr. Zon said. "You would want to find the line
that makes the tissue you are studying."

An Embryo by Cloning

Across the river in Cambridge, in
the basement of a biology building on Harvard's campus, a
small group of scientists works in a two-room lab on the
site of a former machine shop. Among their goals is to
plunge into one of the most controversial areas of stem
cell research - creating human embryos by cloning and
obtaining stem cells from those embryos.

An embryo created by cloning would be an exact genetic
match of the person whose cells were used to make it. Its
stem cells and any mature cells derived from those stem
cells would exactly match the cells in the person's body,
making them perfect replacement cells.

One of the four part-time researchers at the Harvard lab,
Dr. Kevin Eggan, learned to clone mice as a Ph.D. student
at M.I.T. and, he said, the group is seeking approval from
Harvard's ethics committee to try to start the cloning
process with human cells.

The federal government forbids the use of its money to pay
for such research, but this lab, directed by Dr. Douglas A.
Melton, a Harvard developmental biologist, takes no federal
money. Instead, the work is paid for by the Howard Hughes
Foundation, the Juvenile Diabetes Foundation and the Naomi
Berry Diabetes Center of Columbia University.

Cloning, however, can be onerous. In February, researchers
in South Korea announced that they gotten stem cells from
human embryos they created by cloning, but they began with
176 human eggs and ended up with one embryo that yielded
stem cells.

Dr. Eggan, though, is not after replacement cells. His goal
in cloning is to understand what goes wrong in a disease
like Alzheimer's, Parkinson's or diabetes.

Dr. Melton gave an example. Suppose he had stem cells that
were exact matches of 50 patients with Parkinson's disease
and directed them to grow in the laboratory into nerve
cells of the type that die in the disease. He could then
ask when, and why, the cells die.

"Do they all show a defect at the same stage? If so, that
would mean there is a common cause, like a flat tire. Or
maybe each one breaks down in a different way. Is there one
way to get Parkinson's, or 50 ways?" Dr. Melton asked.

"We could use that information to do drug screening," he
added, possibly finding ways to prevent the nerve cell

For now, though, the Harvard lab is becoming a supplier to
the world of its own 17 lines of human embryonic stem
cells, created without cloning, and made from 286 frozen
embryos created by in vitro fertilization.

Realism About Treatments

Meanwhile the national debate
over the use of human embryonic stem cells goes on.

While many Americans say in polls that they favor using
these cells, many others have strong moral objections.
Creating and destroying a human embryo to obtain stem
cells, they say, is ethically unacceptable, and doing
research on human embryonic stem cell lines that are
already in existence does not right the wrong.

It is "a kind of after-the-fact cooperation with this
destruction," said Richard Doerflinger, deputy director of
pro-life activities for the United States Conference of
Catholic Bishops.

The challenge for scientists in the midst of a fierce
political debate, many say, is to be realistic about how
hard it is to develop treatments.

Dr. Battey lists some of the challenges ahead: getting the
cells to develop into exactly the adult cells that are
needed, demonstrating that the adult cells can survive,
preventing rejection and controlling cell growth.

Such issues, Dr. Battey said, "need to be addressed in
animal models before any thoughtful person would go into

Anyway, I just realized that I my Xander-Faith piece for ship_manifesto is due today. EEEEEP~! I thought it wasn't due until August 27 for some reason. I have to email the moderator and let them know I'm running late.

Also, I'm looking for a few good recs for my Xander-Faith piece for ship_manifesto. I know the kinds of Faith-Xander stories I like and I have a couple of authors to recommend, but if some kind soul out there wants to recommend Web sites and authors, I could potentially include, I'd be very happy indeed.

Oh, in other news, the CYA Fic-a-thon is looking for readers to adopt some writers. You can find the link to put in your request here. Adopt a few good authors.

Guess which one I am. No. Seriously. Guess.

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