2005-8-8
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VOICE ONE:
This is SCIENCE IN THE NEWS, in VOA Special English. I'm Barbara Klein.
VOICE TWO:
And I'm Bob Doughty. On our program this week, we tell about medical transplant operations. Doctors perform transplant operations to replace tissue or organs in a person who is sick or injured. Organ transplants help save thousands of lives each year.
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VOICE ONE:
Last year marked the fiftieth anniversary of the first successful transplant of a human organ. An American medical team performed the first successful organ transplant on December twenty-third, nineteen fifty-four. The operation took place at what is now Brigham and Women's Hospital in Boston, Massachusetts.
The patient, Richard Herrick, was dying from a kidney infection. Doctor Joseph Murray led the team that gave Richard a kidney from his twin brother, Ronald. Ronald had the same genes as Richard, but was in excellent health. Richard survived for eight more years with the kidney. In nineteen-ninety, Doctor Murray was given the Nobel Prize in Medicine for his work.
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Experts say the first transplant operation was carried out in eighteen twenty-three. A German doctor placed skin from a woman's leg on her nose. By eighteen sixty-three, a French scientist showed that the body rejects tissue transplants from one person to another. Forty years later, a German scientist found that this rejection was carried out by the body's defense system attacking the foreign tissue.
Rejection continued to be a problem well into the twentieth century. In nineteen fifty-eight, French doctor Jean Dausset discovered a system for tissue matching. This is a way to make sure that the tissue to be transplanted is as similar as possible to the patient's own tissue.
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In nineteen seventy-two, Swiss scientist Jean Borel discovered that the drug cyclosporine could stop the body from rejecting the new organ or tissue. Cyclosporine is a natural product made from a fungus found in soil. Cyclosporine was approved for use in the United States in nineteen eighty-three. Experts say the use of this drug is the most important reason for the success of transplant operations today.
Doctors around the world now can save thousands of lives with transplant operations. American officials say a record number of organ transplants were performed in the United States last year. Nearly twenty-seven thousand people received one or more organs. These people can be expected to survive for many years.
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More than twenty different organs and tissues can be transplanted from one person to another. The organ most commonly transplanted is the kidney. The success rate of kidney transplants is very high. Some kidney transplant patients have survived for more than forty years.
Another commonly transplanted organ is the liver. It is the only organ in the body that can grow to normal size from a small piece. Doctors can remove part of a liver from a person and place it into a patient who has liver failure. After the operation, both livers will grow to full size.
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The South African doctor Christiaan Barnard performed the first successful heart transplant in nineteen sixty-seven. Many more heart transplants have been done since cyclosporine was approved for use.
Experts say the number of heart transplants decreased last year. They say the demand for heart transplants has slowed because of improvements in medical processes and better treatments for heart disease.
Sometimes, lung disease damages the heart. So doctors must replace both the heart and the lungs. The pancreas and the intestines are two other organs that can be transplanted.
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Doctors also perform tissue transplants. The most common is a blood transfusion. People may receive blood after an operation or accident. Blood is considered a tissue. Other tissue transplants involve skin, bone marrow, blood vessels and corneas.
Corneal transplants improve the sight of people whose eyes have been damaged by injury or infection. Such operations have a success rate of more than ninety percent.
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Skin transplants reduce the chance of infection in severely burned areas of skin. These transplants remain on the body for several weeks. This is done until skin from another part of the patient's body can be used for a permanent transplant.
Bone marrow transplants are for people who have diseases such as leukemia, a cancer of the blood. Doctors remove marrow from the hip bone of a healthy person. Then they place it into the sick person where the marrow begins to produce healthy blood cells.
Bones can be transplanted, too. In some countries, doctors have even transplanted arms and hands.
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A transplant operation is successful only if doctors can prevent the body from rejecting the foreign organ or tissue. This is done with drugs like cyclosporine. The patient also must receive tissue that is similar to his or her own. The person providing the tissue or organ is known as the donor. The one receiving it is the recipient.
Both the donor and recipient must have similar blood. For some transplants, they also must have some of the same proteins called H.L.A. antigens. H.L.A. antigens are found on the outside of cells. Each person has many different H.L.A. antigens. The donor and recipient must have several of the same antigens for the transplant to have a chance to succeed.
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Family members are often the best choice for a donor when a person needs a transplant. However, most transplanted organs come from people who have died or been declared brain dead. People who are brain dead usually suffered a head injury. After brain activity ends, doctors can use machines to keep the other organs working. This continues until a transplant recipient is found.
In the United States, a private group keeps a national list of persons who need a transplant. It is called the United Network for Organ Sharing, or UNOS. It says the number of persons waiting for organ transplants has risen sharply in the past fifteen years.
At the time, there were about twenty thousand people on the waiting list. There are about eighty nine thousand now. Each year, more than six thousand Americans die before the organ they need is found.
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Efforts to increase the number of organ donors have helped to reduce the waiting time. UNOS says transplant operations in the United States last year used almost as many organs from living donors as from people who had died.
Kidneys can come from a living donor because a person can live with only one. Living donors can also give part of their liver, pancreas, intestine or a piece of a lung.
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Organ and tissue shortages are a worldwide problem. The shortage of organs has led health officials to begin easing rules about who can give an organ. Some doctors have started accepting organs once considered unusable.
Not surprisingly, some people see a chance for profit. Each year, hundreds of poor people illegally sell their kidneys for later use in transplant operations.
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Some animal organs have been experimentally transplanted into people. Doctors began to perform such operations because of the lack of human organs. Those who continue the experiments say they believe there will never be enough human organs to meet the need.
Many scientists say pigs are the best animals for transplants. Heart valves from pigs are being used to replace diseased or damaged heart valves in people. Scientists say animal tissue could also be useful in countries where human-to-human transplants are not permitted.
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Health care workers around the world say organ and tissue transplants save thousands of lives. Some officials call organ donation the gift of life. They urge people to consider giving permission to use their organs for transplant operations if they should die unexpectedly.
In the United States, people who wish to donate their organs if they die in an accident can state so on their driving permit. A medical organization will then do a computer search for people who need organs and have similar tissue.
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This SCIENCE IN THE NEWS was written and produced by Cynthia Kirk. I'm Bob Doughty.
VOICE ONE:
And I'm Barbara Klein. Join us again next week for more news about science in Special English on the Voice of America.