2004-3-8
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VOICE ONE:
This is Science in the News, in VOA Special English. I'm Sarah
Long.
VOICE TWO:
And I'm Bob Doughty. This week, something new and something old
... the debate over the cloning of human embryos, and the discovery
of the oldest insect ever found.
VOICE ONE:
Plus, some hopeful news from research on a dangerous disorder of
pregnancy.
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VOICE TWO:
Two doctors in South Korea are in
the news a lot these days. They are the first scientists to report
success in efforts to create a human embryo and to remove stem cells
from it. Stem cells have the ability to grow into other cells, such
as heart, nerve or brain cells. So they might offer new ways to
treat disease.
Hwang Woo-suk and Moon Shin-yong are doctors at Seoul National
University. Their study was published in February in Science
magazine.
Sixteen women took part in the research. They agreed to take
fertility drugs for a month. These caused them to produce a large
number of eggs. The doctors collected two-hundred-forty-two eggs for
their study.
They removed the nucleus from each
cell in the eggs. The nucleus contains DNA material, the complete
genetic plans for an organism. Then the researchers used electricity
to join each egg cell to a different cell taken from the women's
ovaries. The ovaries are the organs that produce eggs.
Thirty of the joined cells grew into what are called blastocysts,
an early form of an embryo. The doctors say they were able to
collect stem cells from twenty of them.
VOICE ONE:
There are many political and moral
questions about this work. Lawmakers around the world remain divided
over how to supervise cloning research. But scientists, politicians
and clergy generally agree that cloning should not be used to copy
human beings.
It has been done with animals. In each case, scientists created
an embryo and placed it in a female animal to grow. There was Dolly
the cloned sheep, for example. This form of science is called
reproductive cloning.
But many scientists do support therapeutic cloning for humans.
This is where stem cells are harvested for research on possible
treatments for disease. Supporters argue that cloned stem cells
could be used for gene therapy or to repair tissue. Researchers say
they are still years away from such uses. Yet critics say they fear
that human embryos could become just another industrial product.
Some people would ban any form of cloning.
VOICE TWO:
Doctor Hwang says he understands the issues about his research.
But he says human embryo cloning must go forward to help people with
deadly diseases.
The two doctors are seeking patent ownership rights to the
process they developed. They say they also want to protect the
cloned human stem cells that grew from their experiments.
Seoul National University will own sixty percent of the patent.
Organizations that helped finance the research will own forty
percent.
Hwang Woo Suk and Moon Shin Yong say they are not seeking any
economic gains in the future. They say their only hope is that one
day, their discovery will help solve some incurable disease.
VOICE ONE:
Last week, there was a separate development in the United States.
Harvard University announced plans to build a center to grow and
study human stem cells. Harvard officials in Cambridge,
Massachusetts, say they will pay for the center with private money.
The Bush administration bars the use of federal money for stem
cell research. This is because a developing embryo must be destroyed
in order to collect the cells. Opponents of such research say this
destroys life.
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VOICE TWO:
Some pregnant women develop a condition called preeclampsia
[pre-ee-CLAMP-see-ah]. This causes dangerously high blood pressure.
It causes the urine to contain large amounts of protein. And it
causes fluid to collect in the hands and feet. Preeclampsia can
threaten the life of the mother and her baby. In severe cases, the
woman can suffer seizures and die.
Doctors can treat the effects. But the only cure known is giving
birth. However, babies born to mothers with preeclampsia may be
small for their age. Or they may be born too soon. This puts the
baby at risk for a number of problems.
Researchers say preeclampsia affects about five percent of
pregnancies. It can happen without warning. The cause is unknown.
But new findings may help doctors look for signs of preeclampsia
before it happens, and do more about it.
VOICE ONE:
A study found that two proteins in the blood may point to the
development of preeclampsia. The New England Journal of Medicine
published the findings last month. Researchers from the National
Institutes of Health and Harvard Medical School did the study.
They studied protein levels in blood taken from one
hundred-twenty women who had preeclampsia. The blood had been taken
throughout their pregnancies. They compared the findings to the
blood of one-hundred-twenty other women who had not developed
preeclampsia.
The two groups began their pregnancies with similar levels of the
two proteins measured. But the researchers found that changes took
place in the women who later developed preeclampsia.
Levels of one protein began to increase about five weeks before
the women showed any signs of the condition. Also, levels of the
other protein decreased beginning in the thirteenth and sixteenth
weeks of their pregnancies.
VOICE TWO:
Doctor Richard Levine of the National Institute of Child Health
and Human Development led the study. He notes that the study did not
include women who developed pregnancy-related high blood pressure
but not preeclampsia. So it is not known if these women have similar
changes in their proteins.
But Doctor Levine says the findings do offer the possibility of
preventing and treating preeclampsia.
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VOICE ONE:
Have you heard about the world's oldest insect? Scientists say a
small bug found in Scotland is four-hundred-million years. No, it is
not still alive. The finding suggests that insects existed on Earth
twenty-million years earlier than thought. It also suggests they
were among the first living creatures on land.
The insect was first discovered about eighty years ago. But there
was little interest until two-thousand-two. Then, two scientists
rediscovered it while doing other research. They examined the fossil
at the Natural History Museum in London.
The two are David Grimaldi of the American Museum of Natural
History in New York and Michael Engel of the University of Kansas.
They examined the remains under a powerful microscope. Details of
their discovery appear in Nature magazine.
VOICE TWO:
The scientists say the insect was probably just over one-half
centimeter long. It may have been about the size of a grain of rice
and looked like a small fly. The insect was found in red sandstone
called chert. The scientists say the insect probably became trapped
in crystals that formed around a hot spring.
They examined parts of the head and body. Mister Grimaldi says
the jaws proved it was an insect. He says the jaws were very similar
to those found only in insects with wings. He says he and Mister
Engel became excited at the idea that the insect may have flown.
They did not find any wings. However, Mister Grimaldi says the
jaw parts, or mandibles, provide strong evidence that it had them.
VOICE ONE:
Other scientists agree that this is the oldest insect found so
far. But not all agree that it flew. The oldest known flying insects
-- at least until now -- date back about three-hundred-twenty
million years.
Until now, the oldest insect fossils on record were two insects
without wings. They are said to be about three-hundred-eighty
million years old. They were found in New York State and Canada.
The four-hundred-million-year-old insect is known by the Latin
name Rhyniognatha hirsti. Mister Grimaldi says the finding suggests
that insects likely developed during the Silurian period. This is
the period when evidence shows that plants began to appear on land.
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VOICE TWO:
SCIENCE IN THE NEWS, in VOA Special English, was written by Jill
Moss, Lawan Davis and Cynthia Kirk, who was also our producer. This
is Bob Doughty.
VOICE ONE:
And this is Sarah Long. Listen again next week, when we throw
some light on the dark ... dark energy, that is. Scientists say it
appears to support a theory that Albert Einstein once proposed, and
then rejected.