SCIENCE IN THE NEWS - September 17, 2002: Ginkgo as Memory Aid Disputed / New Findings About
Deadly Skin Cancer / Hair and Sex Lives of Lions
VOICE ONE:
This is Sarah Long.
VOICE TWO:
And this is Steve Ember with Science in the News, a VOA Special English program about recent developments
in science. Today, we tell about a new study of a product people take to improve their memory. We tell some
new information about lions. We tell about an unusual side effect of an anti-cancer drug. And we tell some new
research about a deadly form of skin cancer.
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VOICE ONE:
Memory problems are a sign of old age. A number of products claim to have the ability to improve memory and
other mental activities. Many older adults around the world take a substance called ginkgo in an effort to treat the
problem. Now, a new study is disputing the effectiveness of ginkgo.
Ginkgo is an herb, the part of a plant valued for its medical uses. It comes from the
leaves of the ginkgo biloba tree. Ginkgo is an anti-oxidant, much like vitamins C
and E. Scientists believe anti-oxidants protect the body from damage caused by
harmful oxygen particles called free radicals.
VOICE TWO:
Millions of Americans take ginkgo as a way to improve their memory. They spend
hundreds of millions of dollars on ginkgo products. Doctors in Germany commonly
suggest ginkgo for treating mental problems.
Scientists from Williams College in Williamstown, Massachusetts organized the new ginkgo study. It involved
more than two-hundred people over sixty years of age. All of the people were in good mental health.
For six weeks, half the group took forty milligrams of ginkgo three times a day. The other half took an inactive
substance or placebo. The people did not know which substance they were taking.
VOICE ONE:
The Williams College researchers questioned a close friend of each person about any changes in mental ability.
No differences were observed. Everyone in the study also took a series of tests designed to show their mental
abilities including memory before, during and after the study. The scientists found no measurable improvement in
memory or any other mental ability.
The Journal of the American Medical Association reported the findings. The National Institute on Aging
provided money for the study.
VOICE TWO:
In recent years, the American government has approved such studies to examine claims made by producers of
herbal products. The Food and Drug Administration sets rules for medicines sold in the United States, but not for
herbal products.
Makers of ginkgo were quick to dispute the findings. Boehringer Ingelheim Pharmaceuticals made the ginkgo
products used in the study. A company official said that other studies have found that ginkgo improved people’s
memory. An industry trade group added that larger studies are necessary.
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VOICE ONE:
The lion is perhaps the most famous member of the cat family. Lions are well known for their power and beauty.
Adult male lions are the only cats with manes. This long, thick hair covers the animal’s head and neck.
For years, biologists have wondered why lions have manes or what purpose they
serve. One suggestion is that the thick hair protects a lion’s neck during fights with
other males. Another idea is that the mane is a sign of the male’s physical
condition. This idea says the hair frightens other males and helps females choose
successful mates.
VOICE TWO:
Now, a new American study suggests that manes strongly influence the sex life of
lions. Two University of Minnesota scientists found that female lions in Tanzania
like males with dark manes. Science magazine reported their findings.
Peyton West and Craig Packer studied lions in Tanzania’s world famous Serengeti National Park. They set up
life-size models of lions near where the wild animals live. The models of the lions had different kinds of manes.
Then, they waited to see how the lions would react to the models.
VOICE ONE:
The scientists say the results were clear. Male lions were not afraid to move toward the model lions with short
and light-colored manes. The females were less concerned about hair length. However, they avoided the model
lions with lighter manes. Ninety percent of the time, the females moved toward the model lions with dark hair.
Mizz West said the females seemed to be reacting to the physical condition of the males. She said lions with dark
manes usually have higher levels of the male hormone testosterone. She notes that such lions are more aggressive
fighters. They win fights more often. Her studies show that male lions with dark manes are more likely to recover
from wounds. They also are able to frighten other lions and defend their families.
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VOICE TWO:
A drug normally used to treat cancer has been found to have a surprising side effect. It appears to restore color to
gray hair in some people.
Doctors from the Victor Segalen University in Bordeaux, France were testing the drug,
called Gleevec. Last year, American officials approved Gleevec for treatment of chronic
myeloid leukemia, a rare form of blood cancer.
The French doctors gave the drug to one-hundred-thirty-three leukemia patients. The
drug darkened the hair of nine patients who had gray hair. The darkening effect began
two to fourteen months after the patients began taking the drug.
VOICE ONE:
One doctor said the effect may have been found in even more patients. It was difficult to identify the true
numbers because some patients had used hair coloring products to darken their hair.
The New England Journal of Medicine published the findings. Gleevec has strong side effects. It can damage the
liver and blood. So doctors say the drug should not be used as a hair-coloring product. But scientists have begun
Would he have tried it?
to study the unusual side effect.
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VOICE TWO:
Scientists have discovered a genetic change that can cause malignant melanoma, the most serious kind of skin
cancer. The cancer spreads through the body. Malignant melanoma kills almost forty-thousand people around the
world each year.
The new research was reported in the publication Nature. The work was done by
medical scientists involved in the Cancer Genome Project at the Wellcome Trust
Sanger Institute in Cambridge, England. The aim of the Cancer Genome Project is
to find which of the thirty-thousand human genes are involved in cancer.
VOICE ONE:
Genes contain material called D-N-A. The order of the D-N-A in a gene is
represented by a series of letters. A change, or mutation, happens when the order of the letters changes.
Mutations happen in two ways. Chemicals, radiation or viruses can damage D-N-A. Damage also can result from
mistakes before cells divide.
Most of these mutations are harmless. However, sometimes a mutation in a gene will cause cells to act in an
unusual way. For example, a changed gene will cause a cell to divide when it should stop dividing. Or the cell
will move away from its normal place and into another organ. This is how cancer begins. Experts say it takes
about twenty-five years from the time of the first gene mutation until a cancerous growth appears in adults.
VOICE TWO:
Cancer Genome Project researchers have been examining human genes to find the abnormal genes that cause
cells to become cancerous. The change that causes malignant melanoma is the first one they have found. It is in
the gene called B-R-A-F, one of a group of genes that must all be turned on for a cell to grow and divide.
Scientists say when a gene causes a cell to grow and divide it is “turned on.
”
Normally, it then “turns off”
and stops the cell from dividing any more. The Genome Project scientists found that the mutation makes the gene
stay turned on all the time. It causes the cells to divide and never stop. This leads to cancer.
The researchers say the finding could lead to effective drugs to treat melanoma. They have already started
searching for drugs to make the gene turn off and stop the growth of the cancer. But they also say that people
should try to prevent malignant melanoma from developing by staying out of the sun as much as possible.
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VOICE ONE:
This SCIENCE IN THE NEWS program was written by George Grow and Nancy Steinbach. It was produced by
Cynthia Kirk. This is Sarah Long.
VOICE TWO:
And this is Steve Ember. Join us again next week for more news about science in Special English on the Voice of
America.
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