SCIENCE IN THE NEWS #2082 - Digest

By StaffThis is Steve Ember.And this is Sarah Long with SCIENCE IN THE NEWS, a VOA Special English program about recent developments in Science. Today, we tell about an experimental vaccine to treat Alzheimer's disease. We tell about how genes influence the development of cancer. And we tell about environmental problems in China.

Scientists say tests of an experimental vaccine medicine show that it could be a safe and effective treatment for the brain disorder Alzheimer's disease.

Twelve-million people around the world suffer from Alzheimer's disease. Patients with the disease slowly lose their memory and their ability to think. These changes are caused by the progressive death of brain cells. No one knows what causes Alzheimer's. Scientists do know that the brains of patients contain unusual groups of proteins where nerve cells should be. These protein groups are called amyloid plaques. They are believed to interfere with nerve cells and cause nerve cells to die.Last year, researchers at the Elan Pharmaceutical Company in San Francisco, California reported progress against the disease. They said a new vaccine medicine prevented the formation of plaque in young mice. They said the vaccine also reduced the size of already established plaques in the mice's brains.

Scientists recently reported more progress with the same vaccine. They did so at the World Alzheimer Congress in Washington, D. C. The meeting was the first time scientists from all over the world came together to share information about research and care of people with Alzheimer's disease.A team from the University of Toronto in Canada told the meeting that their tests showed that the vaccine improves thinking ability in mice. And Elan Company researchers said its own human studies have shown the vaccine is safe for people. The company tested the vaccine's safety in twenty-four people with Alzheimer's disease. The patients took the vaccine once with no harmful effects. Eighty more people in Britain soon will also receive the vaccine.

Dale Schenk (SHENK) and other researchers at the Elan Company developed the vaccine. He says the vaccine causes the body's defense system to destroy plaques just like the immune system destroys invading viruses or bacteria. He says the studies show that the vaccine causes immune system cells to remove the plaques from the mice's brains.Researchers say much more work must be done before the vaccine could be used to treat or possibly prevent Alzheimer's disease in people. Future studies will have to show that the vaccine affects the human brain the same way it affects the brains of mice. Medical researchers are still not sure if the plaques in the brains of Alzheimer's patients are the cause or the result of the disease. And scientists must show that destroying the plaques will also destroy the disease.The vaccine is different from drugs currently used to treat Alzheimer's disease. These drugs treat only the signs of the disease. They provide only temporary help because they do not prevent brain cells from dying. The Elan Company is planning larger tests of the experimental vaccine next year. The first series of tests will show if the vaccine is safe for Alzheimer's patients. Only then will it be tested for effectiveness.

((MUSIC BRIDGE))You are listening to the Special English program SCIENCE IN THE NEWS on VOA. This is Sarah Long with Steve Ember in Washington.


There have been many reports recently about the new map of human genetic material -- the human genome. Experts say the human genome will help doctors identify people who have a higher risk of developing cancer or other diseases.

However, a new study shows that genes have only a minor influence in the development of many kinds of cancer. The study says that the environment has a much greater influence on cancer than genetics. The findings were published in the New England Journal of Medicine.Research scientists in Europe studied information about the health of almost ninety-thousand people from Denmark, Finland and Sweden. Each person studied was a twin, one of two babies born at the same time. Some were identical twins. They had the same genetic material. Others were fraternal twins who did not have the same genes.

The researchers say studies of twins make it possible to estimate the effect of genes in the development of cancer. The researchers studied the cancer risks in the people whose twin had cancer. They used mathematics to estimate the importance of genetic and environmental influences in causing cancer.The researchers say they found that forty-two percent of the risk for prostate cancer may be the result of genes. They found that genes are responsible for thirty-five percent of the risk for colon cancer. Twenty-seven percent of the risk for breast cancer was linked to genes. The genetic risk for leukemia and cancers of the stomach, lung, pancreas, ovary and bladder was even lower.

Paul Lichtenstein of the Karolinska Institute in Stockholm, Sweden led the study. He says the study shows that environmental influences are more likely to cause cancer than genetic influences. These environmental influences include how people live and what they eat, drink, breathe and smoke. And they include how people are affected by radiation, chemical pollutants and viral infections.

The director of the American National Cancer Institute wrote a commentary published with the findings. He said the study shows most people are not likely to develop cancer because of their genes.

((MUSIC BRIDGE))The State Environmental Protection Administration in China says more must be done to protect the environment. It says many rivers in China are severely polluted. And its says air pollution levels are too high. The minister of the State Environmental Protection Administration says the government will increase its efforts to clean up pollution. He spoke during a press conference last month.

Officials say China's environment has suffered as a result of years of harmful policies designed to speed industrial development and expand grain harvests. The policies were put into effect to help feed more than one-thousand-million people in China.Experts say China's rivers are among the dirtiest in the world. A government report says two-thirds of the Yellow River is badly polluted. Environmental officials say they plan to establish protected areas and observations stations along the Yellow River and the Yangtze River. They want to inform the public about environmental problems.

The environmental protection agency says the air in almost forty-percent of China's cities is seriously polluted. Adding to the pollution has been a severe lack of rain. The drought has lowered water levels and increased the build-up of harmful chemicals.

China's new pollution control efforts have mostly targeted industrial polluters. Government agencies are now starting to examine agricultural waste.In recent years, the Chinese government has dealt with problems of law enforcement. It has strengthened its inspection system, especially along the seven major rivers. Many polluters have had to pay fines. And, the Environmental Protection Administration has taken hundreds of cases to court. Chinese environmental officials say there have been some improvements. They say eighty-one percent of more than two-hundred-thousand polluting industries are meeting environmental protection rules. Also, unleaded gasoline is helping to reduce air pollution. And they say more than thirty-thousand coal mines in China have been closed.

This SCIENCE IN THE NEWS program was written by Nancy Steinbach, George Grow and Cynthia Kirk. It was produced by George Grow. This is Sarah Long.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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