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SCIENCE IN THE NEWS #2095 - 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 a link between early birth control pills and breast cancer. We tell about a link between soft drinks and broken bones. We tell about a protein that turns cells to fat or muscle. And we tell about a treatment that delays the signs of the disease multiple sclerosis.

The Journal of the American Medical Association has published a new study about breast cancer. Women in the study took pills to prevent pregnancy more than fifteen years ago. These same women also had mothers or sisters with breast cancer.

The new research shows that such women are three times more likely than others to develop breast cancer. However, the study did not find an increase in breast cancer among women who took birth control pills after Nineteen-Seventy-Five.

Some of the women in the study had at least five family members with breast cancer or cancer of the ovaries. These women showed a greatly increased chance of developing breast cancer. They were eleven times more likely to develop the disease than other women who did not take birth control pills.Thomas Sellers led the study. He is with the Mayo Clinic Cancer Center in Rochester, Minnesota. Doctors from the Mayo Clinic and the University of Minnesota did the research. Their work suggested that the risks may be linked only to older birth control pills. Pills made before Nineteen-Seventy-Five contained more of the female hormones estrogen and progestins.

Estrogen is known to increase growth of breast cancer cells. But the report says it is not clear if the risk is connected only to the older pills.The Minnesota researchers studied more than six-thousand women. They were the daughters, sisters and other family members of four-hundred-twenty-six breast-cancer patients. The women had breast cancer between Nineteen-Forty-Four and Nineteen-Fifty-Two.

The granddaughters of the cancer patients also were included in the study. These granddaughters did not show a higher risk for breast cancer. But they were an average of forty-three years old. Doctor Sellers said this might mean that the granddaughters were not old enough to develop breast cancer.

Some doctors say they will advise patients like those in the study to avoid birth control pills. Others say they will continue to suggest birth control pills because studies show they lower the risk of ovarian cancer. This cancer is more deadly than breast cancer.

((MUSIC BRIDGE))An American study has shown a link between soft drinks and broken bones. The study found that teenage girls who drink soft drinks like colas have a greater risk of suffering broken bones than girls who do not drink colas.

Grace Wyshak of Harvard University in Cambridge, Massachusetts organized the study. She suggested that girls who drink soft drinks are not drinking enough milk. Calcium in milk strengthens bones.

The findings were published in Archives of Pediatrics and Adolescent Medicine. Mizz Wyshak questioned four-hundred-sixty girls between the ages of fourteen and sixteen. She asked them about their levels of physical activity, history of broken bones, and how often they had colas or other soft drinks.Mizz Wyshak found that the girls who drank soft drinks were three times more likely to have a broken bone than girls who did not drink colas. The risk of broken bones was five times greater for active girls who drank cola soft drinks.

Mizz Wyshak suggested that a chemical used in cola soft drinks - phosphoric acid - may weaken bones. Phosphorus has been showed to limit bone development.

However, a spokesman for the National Soft Drink Association questioned the results of the study. He said there is no scientific evidence that anything in colas causes broken bones.

The magazine published a commentary by Neville Golden of the Albert Einstein College of Medicine in New York. He said more studies are needed to confirm the findings.

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

Scientists at the University of Michigan in Ann Arbor have discovered a protein that causes developing cells to become either muscle or fat. Scientists say the discovery may help increase understanding about how people become overweight.

Muscle and fat cells both begin as stem cells. They later become precursor cells. A group of proteins controls what precursor cells become. Researchers say one of these proteins appears to block the production of fat cells. When the protein links with some precursor cells, they develop into muscle. But when the protein is missing, the same cells will turn into fat.The researchers discovered the action of the protein in test tubes, and then later in mice. They injected pre-fat cells under the animals' skin. Areas of fat formed after the injection, but only in those cells lacking the protein. Until now, scientists thought that only fat precursors turn into fat cells. But the study shows that muscle precursors can also become fat cells.

University of Michigan scientist Ormond MacDougald was a leading researcher on the study. He says he believes that precursor cells for other substances such as blood, bone and cartilage can also become fat cells if the protein is missing. However, he says there is no evidence for that at this time.

((MUSIC BRIDGE))Researchers in the United States and Canada have shown for the first time that a drug can delay or reduce the signs of the disease multiple sclerosis.

Multiple sclerosis is also called M-S. Its cause is unknown. The disease results when the body's defense system attacks the nervous system. It destroys the protective tissue around nerves in the brain and spinal cord. This temporarily blocks signals that pass through the nerves to the muscles and brain. The disease later damages the nerves, too. M-S especially affects the ability to see, the sense of touch and the use of the arms and legs. The disease usually gets worse as time passes.The latest study involved a drug called Avonex, or interferon beta one-A. It is already used to treat M-S. Researchers at fifty hospitals in the United States and Canada treated three-hundred-eighty-three people. All the people had very early signs of M-S. All had suffered one attack of the disease. They experienced double vision or problems with balance and strength. They also suffered some problems with controlling expulsion of wastes. Tests showed evidence of nerve damage in their brains.

Patients are usually not considered to have M-S until they suffer two attacks at different times that affect different parts of the brain. But people who suffer one attack are considered highly likely to develop the disease.About half the patients in the study took the Avonex drug. The other half took an inactive substance. Seventy-six people in the group taking the inactive substance developed M-S. Only forty-six people taking Avonex developed the disease. The patients taking Avonex also showed fewer signs of nerve damage in the brain than those in the other group.

Researchers designed the study to follow these patients for four years. But officials stopped the study a year early because the Avonex group was doing so much better than the other group. Then they offered the drug to all the patients.

Stephen Reingold is with the National Multiple Sclerosis Society. He praised the study. But he said it did not continue long enough to show that Avonex prevents multiple sclerosis. He said the study does show that the drug delays the disease.

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