This is SCIENCE IN THE NEWS in VOA Special
English. I'm Bob Doughty.
I'm Barbara Klein. This week, we tell
about how thin monkeys live longer than fat ones, how aspirin can help colon
cancer patients and some new information about Tyrannosaurus rex.
study of monkeys over a twenty-year period suggests that eating less may extend
life and prevent disease. American
researchers said they believe their findings could apply to people as well.
Their study was published in the journal Science.
Richard Weindruch of the University of Wisconsin
in Madison and his team did the research. They tested the effects of calorie
restriction in seventy-six rhesus monkeys over twenty years.
Half of the
monkeys were permitted to eat as much as they wanted. The other half ate a
controlled diet. They were fed two-thirds of the calories they would otherwise
choose to eat. These monkeys were given vitamins and minerals to prevent
The researchers found
that thirty-seven percent of the monkeys that ate as much as they wanted had
died of causes related to aging after twenty years. In comparison, only thirteen
percent of the monkeys on restricted diets had died.
average, rhesus monkeys live about twenty-seven years in captivity, that is,
when they live with humans and not in the wild. Mister Weindruch says researchers do not know why reducing calories
increases the length of life. But they believe there is a helpful change in the
way the body processes energy in the monkeys that eat fewer calories.
life was not the only observable difference between the two groups. The monkeys
that ate less had half the amount of heart disease and cancer. They also had no
cases of the disease diabetes. Richard
WEINDRUCH: "Our data show that there is about a three-fold higher risk of
developing a disease of aging in those animals fed the normal diet as opposed
to those that have been on caloric restriction since they were adults."
Weindruch says not only is life extended in the monkeys that eat less, but
their quality of life is also improved. He noted another surprising observation
in the monkeys on a restricted diet. There was a delay in muscle loss and brain shrinkage that lead to mental
problems linked to aging.
addition, there is also a difference in the appearance of calorie-restricted
monkeys and those on a normal diet. The monkeys that ate fewer calories look
younger and healthier than fatter monkeys on an unrestricted diet.
The study was paid
for by the United States National Institute on Aging. Some critics say more
research is needed to prove that calorie restriction extends life in monkeys.
Mister Weindruch says his study is not complete and that his team will continue
to observe the remaining monkeys throughout their lives.
first studied the effects of calorie restriction on aging in the nineteen
thirties. Since then, similar studies have shown life-extending effects of
reduced diets on rodents, yeast and worms. Scientists are currently studying
the effects of restricted diets on people. However, this is more difficult
because it is harder to control the diets of people and because they live
longer than other animals.
People since ancient times have used aspirin-like
medicines to fight pain and reduce high body temperature. Modern research has found other uses for
aspirin. The drug acts as a blood thinner. It can help blood flow past a
blockage in an artery. Blockages can cause heart attacks or strokes. As a
result, patients at risk of blockages might be advised by their doctors to take
a low-strength aspirin every day. And research continues. A new study has shown
that aspirin can improve survival in colon cancer patients.
The study involved about one thousand three
hundred patients with colorectal cancer. The cancer had not spread to other
parts of the body yet. The study compared patients who took three hundred
twenty-five milligrams of aspirin at least two times a week with those who did
not use aspirin.
The study found that the aspirin users had an almost
thirty percent lower risk of dying from their cancer. That was during an
average of eleven years after the cancer was discovered.
Chan of Harvard Medical School and Massachusetts General Hospital led the
study. Doctor Chan says the effects appeared especially strong among patients
with tumors expressing an enzyme called COX-2. Two-thirds of colorectal cancers
produce that chemical. Doctor Chan thinks the aspirin works by blocking
appeared in the Journal of the American Medical Association. It was an
observational study. In a controlled study, some patients would have taken
aspirin. Others would have received a placebo -- sugar pills -- for comparison.
Last year, Doctor Chan reported that a long-term study
of almost fifty thousand men showed that aspirin can help prevent colon cancer.
But the effects required at least six years of regular use. And the greatest
risk reductions were in those who took more than fourteen aspirins per week.
the researchers warned that the dangers from such large amounts of aspirin
should be carefully considered. Aspirin
is a kind of nonsteroidal anti-inflammatory drug, or NSAID. The earlier study
found comparable reductions from the use of other NSAIDs, but not from the use
All of these drugs have their uses but
they also have risks. Aspirin can cause bleeding in the stomach, the intestines
and the brain. People who might want to consider taking aspirin as a
preventative measure should first talk to a doctor.
is new information about Tyrannosaurus rex, the most widely recognized dinosaur
and a favorite among children. Many children's books show T.rex fighting bloody
battles with other huge dinosaurs.
now it seems that T.rex may not have been as fierce as scientists once
means "tyrant lizard" and "rex" is Latin for "king." The Tyrannosaurus lived in North America
during the late Cretaceous Period. The huge animals died out about sixty-five
million years ago.
T.rex was one of the largest meat-eating
dinosaurs that ever lived. It stood four
to six meters tall, was about twelve meters long, and weighed up to seven tons. Its huge head was one and a half meters
long. It also had sharp, bone-crushing teeth. The animal was believed to be a fierce
predator that ate other dinosaurs.
Scientists believed the
Tyrannosaurus ate even larger plant-eating dinosaurs. And, they believed T.rex could eat up to two
hundred thirty kilograms of meat in one bite. But new research suggests that the deadly dinos may not have been as fierce
as earlier believed.
Rauhut is a paleontologist at Ludwig Maximilians University of Munich in
Germany. David Hone is a paleontologist
at the Institute of Vertebrate Paleontology and Paleoanthropology of China in
two scientists have concluded from fossil records that giant meat-eating dinosaurs
like the Tyrannosaurus rex mainly ate young dinosaurs. Fossil records of the stomach contents of the
larger dinosaurs suggest they swallowed these young dinosaurs whole.
scientists say this belief is further supported by the fact that past discoveries
from dinosaur areas show they contained large numbers of dinosaur eggs. This should have resulted in a large number
of baby dinosaurs. But Mister Rauhut
says fossil records show that this is not the case. He says young dinosaur fossils are extremely
rare, a possible sign that many of them had been eaten by attackers.
Hone says the records suggest that Tyrannosaurus rex was like many other
predators. It attacked young, old or
sick animals that were not much of a threat.
There are some signs of conflict between T-rex and
other large dinosaurs. But, Mister Hone
says the records seem to suggest that those were few. The scientists say they hope more fossils
will be found that support their beliefs.
SCIENCE IN THE NEWS was written by Caty Weaver, June Simms and Brianna Blake
who was also the producer. I'm Bob
I'm Barbara Klein. For transcripts, MP3s
and podcasts of our shows, go to our Web site, voaspecialenglish.com. Listen
again next week for more news about science in Special English on the Voice of