SCIENCE IN THE NEWS #2088 - Digest

By StaffThis is Sarah Long.And this is Bob Doughty with SCIENCE IN THE NEWS, a VOA Special English program about recent developments in science. Today, we tell about scientists who grew nerve cells from special stem cells. We tell about cancer patients who suffer memory loss from chemotherapy treatments. And we tell about a rare red panda born in an American zoo.

American scientists have found a way to change bone marrow cells into nerve cells like those found in the brain and the spinal cord. The discovery may lead to safe and successful treatments for nerve injuries and brain disorders.

The work is being done by Ira Black and a team of researchers at the Robert Wood Johnson Medical School in Piscataway, New Jersey.

Doctor Black said he began the research to study how the body's cells, with the same genetic material, become many different kinds of cells. Some become blood cells. Others become liver cells or brain cells.

Doctor Black wondered how this happened. What caused a cell to change into one kind or another? He hoped to learn if scientists could make the same kind of changes in cells.Special cells called stem cells are produced in bone marrow, the material inside the large bones of the body. The stem cells move from the bone marrow to the place where they are needed. For example, if the body needs liver cells, stem cells travel to the liver. They become liver cells and do all the work that other liver cells do.

Doctor Black and his team removed stem cells from the bone marrow of rats. They put the rat stem cells into laboratory dishes and grew many more of them. Then they added a chemical called beta mercaptoethanol. Doctor Black had discovered earlier that beta mercaptoethanol had a special effect on cells. It seemed to block other chemicals that prevented cells from becoming nerve cells.Doctor Black said laboratory stem cells treated with beta mercaptoethanol changed within minutes. He said they looked exactly like nerve cells. They began growing long, hair-like parts, just as nerve cells do.

The researchers found it was possible to change about eighty percent of the stem cells into nerve cells. Tests showed that the newly-created nerve cells did all the chemical work that nerve cells usually do.

Doctor Black transplanted the rat nerve cells he had produced in the laboratory into the brains and spinal cords of living rats. The laboratory nerve cells survived for months in the bodies of the rats.Other scientists praised the discovery. One was William Greenough, of the Beckman Institute for Advanced Science and Technology at the University of Illinois. Doctor Greenough said the discovery was an important step toward developing new technologies for the repair of a damaged brain.

He noted that many scientists are working with embryos or animal tissue to try to develop cells to replace damaged human cells. But the body's defense system often rejects such foreign cells. That would not be a problem with replacement cells grown from a person's own stem cells.

Scientists say, however, that a huge amount of work must be done before laboratory-produced nerve cells can be used to treat human injury or disease. The work done by Doctor Black's team is described in the Journal of Neuroscience Research.

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

Chemotherapy is a common way to fight cancer. Doctors give patients powerful drugs to kill cancer cells. However, chemotherapy drugs often are poisonous to healthy cells as well. Patients often suffer unwanted side effects. Among the most common side effects are a sick feeling in the stomach and the uncontrolled expulsion of food from the mouth. Other side effects are hair loss, a feeling of weakness and infection.

In addition, patients who have traditional chemotherapy often say they suffer from temporary memory loss and reduced thinking ability. Tim Ahles (Ah-less) of Dartmouth Medical School in Hanover, New Hampshire, organized a study of the problem.Doctor Ahles compared cancer patients who had traditional chemotherapy to patients who had limited treatments. The two groups were tested for memory, reading ability, and the ability to think clearly. Doctor Ahles says his study showed that patients who had traditional chemotherapy were two times as likely as the other patients to do poorly in the intelligence tests.

Doctor Ahles presented the findings to a group of cancer patients who had chemotherapy. He says those patients felt better knowing that the study found evidence of what many of them already knew.

Doctor Ahles says almost everyone who has chemotherapy experiences problems with memory and thinking. He says the problems are most common from the middle of treatment until up to four months after the chemotherapy stops. He says the ability to think clearly begins to improve later.Recently, research scientists in Canada reported similar findings about chemotherapy. The findings were reported in the Journal of Clinical Oncology. Researchers from Princess Margaret Hospital in Toronto studied breast cancer patients who were given chemotherapy. They compared the patients to other women who were not receiving the treatment.

The Canadian researchers found the women taking the anti-cancer drugs did worse in tests of memory and language than the other women. The researchers say doctors and patients should understand the problem when making treatment decisions. However, they say this possible problem should not be used as an argument against chemotherapy treatment.

((MUSIC BRIDGE))A rare Chinese red panda has been born at the Red River Zoo in Fargo, North Dakota. Officials there say the birth is believed to be the first at a North Dakota zoo. The Red River Zoo opened last year. The cub's mother is a female red panda called Tsaka, which means "mountain" in Tibetan. Its father is named Chang.

Keepers at the zoo were surprised to discover that Tsaka had given birth in June. They did not announce the birth until they were sure the panda cub would survive. Zoo officials believe the cub is probably male. They have named it Liwu (Lee-Wu) which means "gift" in Mandarin Chinese.

About fifty Chinese red pandas live in zoos in the western part of the world. In the United States, the Knoxville Zoo in the state of Tennessee is best known for its programs to help red pandas reproduce. More pandas have been born there than at any other zoo in the country.The red panda is a small member of the animal family that includes the larger and more famous giant panda. The red panda is similar in size and appearance to a raccoon. Red pandas are known for their soft fur and long thick tails.

Panda cubs are very small when they area born. They weigh about two-hundred grams when they are one week old. When cubs are three months old, they start to look like adult pandas. Adults weight about four kilograms.The red panda lives in the Himalayan Mountains in Nepal, Bhutan, Burma and southern China. It is difficult to know for sure how many red pandas live in the wild. That is because the bamboo forests where they live are very thick.

However, there is increasing evidence that the red panda is becoming endangered. The major threats to pandas are said to be the loss of their native forests and illegal hunting. For example, widespread cutting of forests for wood and farmland in China has destroyed large areas of the pandas' environment.

This SCIENCE IN THE NEWS program was written by Frank Beardsley and George Grow. It was produced by Nancy Steinbach. This is Sarah Long.And this is Bob Doughty. Join us again next week for more news about science in Special English on the Voice of America.

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