SCIENCE IN THE NEWS - French Doctors Perform a Partial Face(在线收听

SCIENCE IN THE NEWS - French Doctors Perform a Partial Face Transplant; Medical, Moral Questions
By Katherine Gypson, Anne Pessala and George Grow

Broadcast: Tuesday, December 13, 2005

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This is SCIENCE IN THE NEWS in VOA Special English. I'm Bob Doughty.

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And I'm Pat Bodnar. We begin this week with a report on the world's first partial face transplant.

VOICE ONE:

Then, a study shows that the drug tamoxifen can help prevent breast cancer in women at high risk.

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And, later, children and the importance of sleep.

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Doctors in France have carried out the first partial face transplant. They took the nose, lips and chin from a woman who was declared brain-dead and used them to repair the face of another woman. The thirty-eight-year-old French woman who received the tissue had been severely injured in the face by her dog.

 
face transplant model
Last week the newspaper Le Parisien published a few comments that it said she made by telephone from her hospital bed. The woman, identified only as Isabelle D., said she was "doing very well." She asked that the media leave her and her family in peace.

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There were still questions, however, about how the woman came to be injured by her dog earlier this year. Some news reports have said she tried to kill herself with sleeping pills. There have been suggestions that her Labrador retriever was just trying to wake her. Her doctors have said repeatedly that she did not try to kill herself. The dog was put to death.

After the injuries, the woman was unable to speak or eat normally. She wore a mask to hide her injuries.

The injuries were so bad that doctors said it might be impossible to repair her face with normal methods. Faces have at least five kinds of skin. For this reason, normal repairs with other tissue do not work well for facial injuries. These operations can leave bad scars on the face.

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Medical progress has made it possible for several years now for doctors to transplant faces. But this is the first time they have performed the operation on a living patient. Doctors at the Cleveland Clinic in the United States had been expected to perform the first operation.

Many doctors, however, say they will not perform a face transplant. There are medical and moral issues. Medical experts note that a person does not need a face to survive. Many people wonder how patients would react when they see someone else's face on their body. A face is an important part of a person's identity.

A face transplant could help an injured patient eat and speak. But those activities can be assisted other ways.

Then there is the question of where to find faces to transplant. Many doctors believe that people would not want to provide the faces of dying family members.

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The transplant operation in Lyon lasted fifteen hours. It took place late last month.

The doctors were not sure what the transplanted face would look like. They say the woman's new face looks very much like her old one.

In a way, the transplant created a third face. It combined the bone structure of the patient with the skin and muscles of the donor. Doctors say the patient looked at herself in a mirror and was very happy with her new face.

The nose, chin and lips came from a woman of the same age, blood type and skin color. The Sunday Times of London has reported that the tissue came from a woman who killed herself. It says her family gave permission for the transplant.

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The body often rejects organs from someone else. It could reject a new face. Transplant patients have to take strong medicines to prevent tissue rejection. But these medicines come with their own risks.

Many doctors say facial transplants should not be performed on people who just want to look better. They say the operation should be saved for patients who cannot eat or speak on their own without a new face.

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VOICE TWO:

You are listening to SCIENCE IN THE NEWS in VOA Special English, from Washington.

A study has confirmed that the drug tamoxifen can prevent breast cancer among women with a high risk of developing the disease.

Tamoxifen is a man-made hormone that blocks the action of the female hormone estrogen. Estrogen causes cancer cells to divide and spread. Earlier studies showed that tamoxifen reduces the chance of breast cancer developing again in women who had been successfully treated for the disease.

A research group in the United States organized the study with support from the National Cancer Institute. The Journal of the National Cancer Institute published the findings.

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The study began in nineteen ninety-two. It involved more than thirteen thousand women who were at high risk of developing breast cancer. All the women were thirty-five years of age and older. The risk of breast cancer increases with age. So women sixty years of age and older were chosen based on age alone.

About half of the women received tamoxifen. The others received an inactive substance, also known as a placebo. Neither the women nor their doctors knew which one the women were taking.

The study found that after five years, women who had used tamoxifen were forty-nine percent less likely to get breast cancer. Study organizers then told the women if they were taking the drug or the placebo. They did this so every woman in the study could decide if she wanted to take the drug.

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Recently, scientists reported final results of the Breast Cancer Prevention Trial. They found that the women who used tamoxifen for at least five years were about forty-three percent less likely to get breast cancer than the other women. There were one hundred forty-five cases of invasive breast cancer among the healthy women who took the drug. Two hundred fifty women who took the placebo developed the disease.

The study organizers also examined possible side effects of tamoxifen. There was almost no difference in the number of heart attacks between the tamoxifen users and women who took the placebo. Women who took the drug reported fewer broken bones in areas such as the hips, wrist and spine. But there was an increased risk of blocked blood passages, and also cancer in the uterus.

The study organizers noted that other methods for preventing breast cancer are being tested. But in their words, "Tamoxifen remains the only proven chemopreventive treatment for breast-cancer risk reduction."

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Reducing the amount of sleep that students get directly affects their performance at school. An American study asked schoolteachers to look at the effects of sleep restriction in children between six and twelve years of age. The teachers found that children who stay up late have trouble thinking clearly and demonstrate more learning problems.

Gahan Fallone supervised the study at the Brown Medical School and Bradley Hospital in the state of Rhode Island. Doctor Fallone now works at the Forest Institute of Professional Psychology in Springfield, Missouri. He presented the results last month at a science reporters conference in Washington, D.C. The publication Sleep also reported the findings.

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The teachers were asked to complete weekly performance reports on seventy-four schoolchildren. The study lasted three weeks. During the period, Doctor Fallone and his team controlled the amount of sleep the children received.

One week, the children went to bed and awoke at their usual times. Another week, every child was kept awake later than normal. Each night, the youngest boys and girls had less than eight hours of sleep. The older ones were limited to six and one-half hours. During the final week of the study, each child received no less than ten hours of sleep a night.

The teachers were not told the amount of sleep the students received. The study found that students who received eight hours or less had the most difficulty remembering old information. They also had trouble learning new information, completing difficult work and following directions.

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The study did not find that sleep restriction caused hyperactivity in the children. The teachers reported that students were, in fact, a little less active at school when they got less sleep.

Doctor Fallone says the results provide experts and parents with a clear message: When a child has learning problems, the issue of sleep must be considered among the possible causes.

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SCIENCE IN THE NEWS was written by Katherine Gypson, Anne Pessala and George Grow. Cynthia Kirk was our producer. I'm Pat Bodnar.

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And I'm Bob Doughty. Our programs are online at www.tingroom.com. Join us again next week for more news about science in Special English on the Voice of America.

  原文地址:http://www.tingroom.com/voa/5/science/18559.html