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14 科技新闻摘要（三）
DATE=5-1-01
TITLE=SCIENCE IN THE NEWS #2122 - Digest
BYLINE=Staff
VOICE ONE:
This is Bob Doughty.
VOICE TWO:
And this is Sarah Long with Science in the News, a VOA Special English program about recent developments in science. Today, we tell about a new (1) genetic treatment for Alzheimer's disease. We tell about the discovery of stem cells in fat. And we tell about the （2）decrease in the number of giant pandas at the Wolong Nature （3）Reserve in China.
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VOICE ONE:
Doctors have placed genetically changed cells into the brain of a woman with Alzheimer's disease. They operated on the sixty-year-old woman in a hospital in California. The patient was showing early signs of Alzheimer's. This （4）experimental operation was an effort to （5）control or stop the （6）destruction of brain cells caused by the disease.
Alzheimer's disease affects millions of people around the world. It damages and destroys cells in many areas of the brain. It slowly robs its (7) victims of intelligence and the ability to remember. As it progresses people can no longer care for themselves. There is no cure.
VOICE TWO:
Mark Tuszynski of the University of California at San Diego developed the new treatment. He says it is the first genetic （8） treatment for a disease that destroys brain tissue. Doctor Tuszynski developed the treatment to increase the effectiveness of a brain chemical called acetylcholine. This chemical is known to fight the brain damage caused by Alzheimer's disease.
Doctors took healthy skin cells from the patient. They added specially treated genes to the cells. These cells were designed to produce a protein called （9）nerve growth factor. Nerve growth factor helps normal brain cells survive and grow. Doctors then placed the genetically changed cells into five areas deep in the right side of the patient's brain. The cells are meant to release nerve growth factor into （10）surrounding areas of the brain.
VOICE ONE:
Hoi Sang U led the team of doctors who operated on the patient. She was treated to prevent pain during the eleven-hour （11）operation. This permitted her to stay awake so the doctors could observe her reactions as they operated.
Doctor Tuszynski says it may be years before they know if the genetic treatment helped this patient. He says placing the genetically changed cells into a damaged brain probably cannot cure the disease. But he says it may help delay the progress of the disease and improve the （12） quality of life. Doctors say they will perform the gene （13） therapy treatment on seven more patients if the first patient shows no bad effects.
VOICE TWO:
Doctor Tuszynski performed research on rats and monkeys for years before testing his treatment on a person. His studies in animals showed the nerve growth factor could help keep some special brain cells healthy. These cholinergic cells are among several kinds of brain cells that Alzheimer's disease destroys. These brain cells are especially important because they help people learn and remember. Cholinergic cells contain the (14) acetylcholine that helps protect normal brain cells.
Doctor Tuszynski received permission from two government agencies to treat Alzheimer's disease patients. The Food and Drug Administration and a committee of the National Institutes of Health approved his research in Nineteen-Ninety-Nine. The F-D-A still must say the process is safe for humans before permitting its effectiveness to be measured.
VOICE ONE:
Some scientists fear the treatment is not safe. They say genetically changed cells might poison the brain or produce a （15）tumor. Or the treatment might cause bleeding in the brain. Earlier tests of nerve growth factor in humans reportedly have caused such problems.
However, these processes were not done by （16）operation. Doctor Tuszynski says he believes his studies have shown this treatment will not produce harmful results. He believes the genetic treatment for Alzheimer's disease can succeed.
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VOICE TWO:
You are listening to the Special English program SCIENCE IN THE NEWS on VOA. This is Sarah Long with Bob Doughty in Washington.
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American medical researchers say they have discovered stem cells in human fat for the first time. Stem cells are able to develop into other kinds of cells, including nerve, bone and muscle cells.
Scientists have been studying the use of stem cells to treat and possibly cure many diseases. These stem cells have the power to grow into new heart muscle for people with heart disease. Or the stem cells can become new insulin-producing cells for people suffering （17）diabetes.
Researchers have collected stem cells from the brain, bones and (18) fetal tissue from unborn babies. Getting these stem cells for research purposes is difficult. And many people are opposed to using fetal tissue for research. The new discovery means that it might be easier to get stem cells for research and treatment of diseases.
VOICE ONE:
Researchers from the University of California at Los Angeles and the University of Pittsburgh carried out the study. The researchers took fat from the stomachs and legs of healthy adults in an operation known as liposuction. About six- hundred- thousand such operations are done in the United States every year. People choose to have liposuction to remove unwanted body fat.
The researchers treated the fat with a substance that separated out the stem cells. They found that about two- hundred grams of fat could produce as many as fifty- million to one- hundred- million stem-like cells. Then they used different chemicals to change those cells into bone cells, (19) cartilage cells and muscle cells.
VOICE TWO:
This is the first study to show that a person's own stem cells in fat might someday be used to treat disease or repair injured body parts. This would solve the problems of （20）rejection by the body because no foreign tissue would be used. Scientists are working to confirm the findings of this experiment. They are testing the stem cells in animals. If this is successful, researchers say human testing could begin in about five years.
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VOICE ONE:
A new report says human activities are harming the Wolong Nature Reserve, China's largest protected area for giant pandas. The report says the environment in the nature reserve is being destroyed quicker than in other parts of China that are not protected. This is causing a decrease in the panda population in the nature reserve. Giant pandas are becoming increasingly rare in the wild. Only about one- thousand of the animals live in the mountains of southwestern China.
VOICE TWO:
Chinese officials established Wolong Nature Reserve in Nineteen-Seventy-Five. It covers two- hundred-t housand hectares of land in Sichuan Province. However, the number of pandas in Wolong has decreased since the reserve was created. The research team says there were one- hundred- forty- five pandas in the reserve in Nineteen-Seventy-Four. Twelve years later, the panda population fell to seventy-two. The team says the number probably is even smaller today.
Giant pandas live in mountain areas where there are plenty of forests. They eat mainly (21) bamboo plants. The researchers compared the rates of change in Wolong's forests and environment before and after the reserve opened. They examined satellite images taken since Nineteen-Sixty-Five.
VOICE ONE:
The researchers found that humans have taken control of large parts of Wolong. Jianguo Liu of Michigan State University led the study. He says human settlements have grown in the reserve, mainly because it has so many visitors. The human population has increased by seventy percent since the reserve was created. The people are cutting more trees for fuel and other uses. This has destroyed areas where pandas live.
Mister Liu's team says the best hope for Wolong is to improve education for the young people who live there. Then they can get jobs and move to other parts of China.
A panda expert at the World Wildlife Fund says China has more than thirty other protected areas for giant pandas. Most of them are not threatened by human activities. And she says panda protection is becoming very important in China.
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VOICE TWO:
This SCIENCE IN THE NEWS program was written by Jerilyn Watson, Nancy Steinbach and George Grow. It was produced by George Grow. This is Sarah Long.
VOICE ONE:
And this is Bob Doughty. Join us again next week for more news about science in Special English on the Voice of America.
注释：
（1） genetic[ dVi5netik ]adj.遗传的, 起源的
（2） decrease[ di:5kri:s ]n.减少, 减少之量v.减少
（3） reserve[ ri5zE:v ]n.储备(物), 储藏量v.储备, 保存
（4） experimental [ eks7peri5mentl ]adj.实验的, 根据实验的
（5） control[kEn5trol]n.控制, 支配v.控制, 支配
（6） destruction[ dis5trQkFEn ]n.破坏, 毁灭
（7） victim[ 5viktim ]n.受害人, 牺牲者
（8） treatment[ 5tri:tmEnt ]n.待遇, 对待
（9） nerve[ nE:v ]n.神经, 胆量v.鼓起勇气
（10） surrounding[ sE5raundiN ]n.围绕物, 环境adj.周围的
（11） operation[ 7CpE5reiFEn ]n.运转, 操作
（12） quality[ 5kwCliti ]n.质量, 品质
（13） therapy[ 5WerEpi ]n.治疗
（14） acetylcholine[ E7si:tEl5kEulin ]n.[化]乙酰胆碱
（15） tumor[ 5tju:mE ]n.瘤
（16） operation[ 7CpE5reiFEn ]n.运转, 操作
（17） diabetes[ 7daiE5bi:ti:z, -ti:s ]n.[医] 糖尿病, 多尿症
（18） fetal[ 5fi:tl ]adj.胎儿的, 胎的
（19） cartilage[ 5kB:tilidV ]n.[解剖]软骨
（20） rejection[ ri5dVekFEn ]n.拒绝
（21） bamboo[ bAm5bu: ]n.竹子
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