SCIENCE IN THE NEWS, in VOA Special English.
I'm Steve Ember.
And I'm Barbara Klein.
This week -- the story of aspirin.
story begins with the willow tree.
Since ancient times, people have known about its ability to reduce pain
and high body temperature. More than
two thousand years ago, the Greek doctor Hippocrates advised his patients to
chew on the bark and leaves of the willow.
tree contains a chemical called salicin.
From salicin, researchers in the eighteen hundreds discovered how to
make salicylic acid. And in eighteen
ninety-seven, a chemist named Felix Hoffmann at Friedrich Bayer and Company in
Germany created acetyl salicylic acid.
it became the active substance in a new medicine that Bayer called
aspirin. The "a" came from
acetyl. The "spir" came from
the spirea plant, which also produces salicin.
And the "in"? Well,
that is a common way to end medicine names.
nineteen eighty-two, a British scientist shared the Nobel Prize in Medicine in
part for discovering how aspirin works.
Sir John Vane found that aspirin blocks the body from making natural
substances called prostaglandins.
Prostaglandins have several effects on
the body. Some cause pain and the
expansion, or swelling, of damaged tissue.
Others protect the lining of the stomach and small intestine.
also make the heart, kidneys and blood vessels work well. But there is a problem. Aspirin works against all prostaglandins,
good and bad.
learned how aspirin interferes with an enzyme.
One form of this enzyme makes the prostaglandin that causes pain and
swelling. Another form of the enzyme
creates a protective effect. So aspirin
can reduce pain and swelling in damaged tissues. But it can also harm the inside of the stomach and small
aspirin competes with a lot of other medicines for headaches, muscle pain and
fever. These include acetaminophen, the
active substance in products like Tylenol.
many people take aspirin to reduce the risk of a heart attack or stroke from
blood clots. Clots can block the flow
of blood to the heart or brain and cause a heart attack or stroke. Scientists say aspirin prevents blood cells
called platelets from sticking together to form clots.
California doctor named Lawrence Craven first noted this effect more than fifty
years ago. He observed unusual bleeding
in children who chewed on an aspirin product to ease the pain after a common
Craven believed that the bleeding was because aspirin prevented blood from
thickening. He thought that this effect
might help prevent heart attacks caused by blood clots.
examined the medical records of eight thousand aspirin users and found no heart
attacks in this group. He invited other
scientists to test his ideas. But it
was years before large studies took place.
Charles Hennekens of Harvard Medical
School led one of the studies. In
nineteen eighty-three, he began to study more than twenty-two thousand healthy
male doctors over forty years of age.
Half took an aspirin every other day.
The others took what they thought was aspirin. It was only a placebo, an inactive substance.
years later, Doctor Hennekens reported that those who took aspirin reduced
their risk of a heart attack. But they
also had a higher risk of bleeding in the brain than the other doctors.
More recently, a group of experts examined studies of
aspirin at the request of federal health officials in the United States. The experts said people with an increased
risk of a heart attack should take a low-strength aspirin every day.
People who are most likely to suffer a
heart attack include men over forty and women over fifty. People who are overweight or smoke are also
at greater risk. So are people with
heart disease, diabetes, high blood pressure or high cholesterol.
In two thousand five, scientists reported the results of
a major study that confirmed that aspirin also helps women. But the results were surprising. The study found that aspirin did not reduce
the risk of a first heart attack in women.
But women who took aspirin were
seventeen percent less likely to have a stroke than women who took a placebo. And they were twenty-four percent less
likely to have the most common form of stroke.
The effects were greatest in women sixty-five years of age and older.
The results were the opposite of what
doctors see in men.
The study lasted ten years. It involved forty thousand women age
forty-five to eighty. The women who
took aspirin were given one hundred milligrams every other day.
Aspirin may help someone who is having a
heart attack caused by a blockage in an artery. Aspirin thins the blood, so it may be able to flow past the
blockage. But heart experts say people
should seek emergency help immediately.
They say an aspirin is no substitute for treatment.
people should not take aspirin. These
include people who take other blood thinners or have bleeding disorders. Pregnant women are usually told to avoid
aspirin. And children who take aspirin
can suffer a disease called Reye's syndrome.
can also interfere with other medicines, although this is true of many drugs.
well-known risk of aspirin is stomach bleeding. Acid in the drug can damage the tissue of the stomach or
intestines. Yet some studies have found
that aspirin may help prevent cancers of the stomach, intestines and
recent study showed that aspirin blocks the formation of blood vessels that
feed the growth of cancer. Researchers
at Newcastle University in England explored a biological process that makes
blood vessels grow. The researchers
studied how aspirin affects the cells found on the inner surface of blood
vessels. They found that a small amount
of aspirin suppressed the way the cells form tubes.
lead researcher Helen Arthur says people with cancer should not take aspirin
unless they are advised to do so by a doctor.
She warns that large amounts of aspirin over a long period can cause
severe stomach bleeding and death.
is one of a group of medicines known as NSAIDs -- non-steroidal
Another example is ibuprofen. Several
studies have found that men who take NSAIDS have a decreased risk of prostate
cancer. Researchers at the Mayo Clinic
in Minnesota wanted to see how NSAIDS might affect prostates that are enlarged
but not cancerous.
followed the health of two thousand five hundred men for twelve years. One-third were
taking NSAIDs daily when they entered the study.
The scientists recently announced that
these drugs may delay or prevent the development of an enlarged
said the risk of an enlarged prostate was fifty percent lower in the NSAID
users than the other men. And the risk
of bladder problems was thirty-five percent lower.
prostate gland is part of the male reproductive system and is just below
the bladder. Growth
of the prostate is common as men get older.
It can mean repeated visits to the bathroom and other effects on a man's
quality of life.
scientists say that because of risks like stomach bleeding, they are not
advising all men to take aspirin. If
men are taking it already, they say, then the findings suggest another way it
might help. The reasons are not
clear, though, and the findings must be reproduced by other studies.
Most of the men were taking
aspirin. But the study found that other
kinds of NSAIDs appeared to have the same effect. And the amount taken did not seem to make much difference either.
any case, medical experts say people should not take aspirin for disease
prevention without first talking to a doctor.
There are risks, and researchers have reported that some people get
little or no protection from aspirin.
But medical research continues to give new life to one of the oldest and
most widely used drugs in the world.
IN THE NEWS was written by George Grow and produced by Brianna Blake. For more science news, and MP3 files and
transcripts of our programs, go to voaspecialenglish.com. I'm Barbara Klein.
And I'm Steve Ember. We hope you can
join us again next week for more news about science in Special English on the
Voice of America.