Science News Digest
This 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 too much weight gain during pregnancy and breast cancer. We tell about some fishy space food. We also tell about a new treatment for a serious skin disease. And we tell about a new study of hormone replacement.
A new study has shown a possible link between too much weight gain during pregnancy and breast cancer. It found that women who gain more than seventeen kilograms during pregnancy may increase their risk of breast cancer later in life.
The study found such women may have a forty percent greater risk of breast cancer later in life than women who gain less weight. It also found that weight gain during pregnancy had no effect on a woman's risk of breast cancer during her reproductive years.
The findings were released at a meeting of the American Association for Cancer Research. Representatives of the group met in San Francisco, California, last month.
In the study, researchers from the United States and Finland examined medical information about more than twenty-thousand Finnish women. For record-keeping purposes, the researchers divided the women into two groups. More than seventeen-thousand women were in one group. Ninety-eight of these women developed breast cancer at an average age of forty-seven. Each of them was still having fertile periods.
The second group included more than three-thousand women. One-hundred-eighty-five of these women developed breast cancer at an average age of fifty-eight. They all were too old to have fertile periods.
Leena Hilakivi-Clarke (LAY-na HILL-ah-kee-vee-CLARK) of Georgetown University in Washington, D.C., was one of the study's investigators. She said the study shows that women who kept the added weight after pregnancy are at the greatest risk. She said the additional weight may cause changes in breast tissue that increase the risk of breast cancer later in life.
Doctor Hilakivi-Clarke said the increased risk that results from weight gain during pregnancy is usually small. She noted that many doctors urge a woman to gain between eleven and sixteen kilograms during pregnancy. She said such a weight gain is not linked with an increased risk of breast cancer.
The researcher also noted the link between high levels of the female hormone estrogen and the risk of breast cancer. She said that at least one study has shown that women who gain the most weight during pregnancy have higher estrogen levels than women who gain less. She said women who have the highest estrogen levels during pregnancy are more likely to develop breast cancer.
Have you ever wondered what it is like to eat in space? Scientists at the American space agency have studied the question of food for astronauts since the beginning of the space program.
Without the force of gravity, objects like small pieces of food float freely inside a spaceship. This could be dangerous in a small area filled with electronic devices. So, NASA made space food into thick, unpleasant substances that do not break into small pieces.
John Glenn, an astronaut for project Mercury, was the first American to eat in space. Most early astronauts regretted the experience. Yet, NASA has done a lot of research to improve the food that astronauts eat. The space agency also wants to develop renewable food resources that can make astronauts depend less on materials brought from Earth. Today, NASA runs a whole center for food research at the Space Food Systems Laboratory in Houston, Texas.
NASA has improved the taste of space food through the years. For example, astronauts on the International Space Station now enjoy foods common to many different cultures. However, some of the new ideas for making foods that can be used on long space flights may seem very unusual, or "out of this world."
One NASA researcher thinks astronauts some day may eat meat that is grown in chemicals. Morris Benjaminson is a scientist at Touro College in Bay Shore, New York. He has been investigating new ways to make food to feed astronauts on long space trips. Mr. Benjaminson performed an experiment using a special fluid taken from the blood of an unborn cow. The fluid is normally used to grow cells.
Mr. Benjaminson and his team put a small piece of fish in the fluid. After one week, Mr. Benjaminson found that the piece of fish had grown by fourteen percent. The biology researchers then cooked the piece of fish. All the researchers agreed that it looked and smelled like fish. But, no one would eat it.
Mr. Benjaminson pointed out that the researchers could not eat the strange food because it was experimental. He explained that the fish had not been approved by the United States Food and Drug Administration.
Doctors from the United States and Saudi Arabia have discovered a new treatment for the form of leishmaniasis (LEASH-ma-NIGH-a-sis) disease that affects the skin. Leishmaniasis is caused by tiny organisms called parasites. Small insects called sand flies spread the disease.
The disease causes serious wounds on the face, arms and legs. This form of leishmaniasis is the most common and represents up to seventy-five percent of all new cases.
The Saudi and American doctors found that the drug fluconazole (floo-KAHN-uh-zol) can be used to treat cutaneous or skin-related leishmaniasis. Fluconazole is used to treat other skin diseases.
James Maguire is an expert on parasite diseases at the United States Centers for Disease Control. He took part in the latest study. It tested fluconazole on more than one-hundred patients in Saudi Arabia. One group of patients was given the drug every day for six weeks. The other group was given an inactive substance.
The doctors found that almost eighty percent of the patients taking fluconazole were completely healed. The doctors also discovered that patients experienced fewer side effects from fluconazole compared to older drugs used to treat leishmaniasis.
The doctors say the drug is effective against the most common form of cutaneous leishmaniasis in the Middle East and parts of Africa. However, they say it does not work well on the kind of the disease found in South Asia and South America.
An international team of health experts says there is no scientific evidence that hormone replacement can treat serious conditions suffered by older women. Women's bodies stop producing the hormone estrogen at about the age of fifty.
Until now, medical experts believed that taking the hormone estrogen could protect older women from health problems. These include heart disease, mental depression, Alzheimer's disease and broken bones caused by the disease osteoporosis.
The report examined the results of many women's health studies. Twenty-eight doctors and scientists wrote the report. They are from the United States, Italy, Sweden, Switzerland and Australia.
The group examined only studies that used the scientific method called a randomized control trial. In such studies, people are given either the treatment being tested or an inactive substance called a placebo. The results show if the treatment was more effective than the placebo.
The report said that hormone replacement is useful to ease the hot feelings that some older women experience. But it said scientific evidence does not support its use for other problems.
For example, three recent studies show that taking hormones increases instead of reduces the chance of a heart attack or stroke. Studies have shown that taking hormones does not help women with early Alzheimer's disease or mental depression. The report said taking hormones can slow bone loss. But the loss continues after women stop taking the hormones.
This SCIENCE IN THE NEWS program was written by George Grow, Mario Ritter, Jill Moss and Nancy Steinbach. This is Bob Doughty. And this is Sarah Long. Join us again next week for more news about science in Special English on the Voice of America.