Antibiotics and Breast Cancer / Mountain Gorillas / Protecting AIDS Babies / Explosion Lab
This is SCIENCE IN THE NEWS, in VOA Special English. I'm Bob Doughty. And I'm Sarah Long. This week -- a study of antibiotics and breast cancer ... plus, findings that a way to protect babies from AIDS may not be so good for their mothers.
Also ... an explosion laboratory with a burst of creativity ... and a possible sign of recovery for mountain gorillas in Africa.
A study suggests a possible connection between use of antibiotic drugs and increased risk of breast cancer. However, the study does not answer the question if antibiotics are a cause of breast cancer. The study appeared last week in the Journal of the American Medical Association.
Researchers in the American Northwest studied more than ten thousand women. The study involved members of Group Health Cooperative, a health plan based in Seattle, Washington.
Antibiotics are used to fight many different kinds of infections caused by bacteria. The study found that women who took more antibiotics compared to other women had higher rates of breast cancer. Some women had taken antibiotics for more than five-hundred days over an average period of seventeen years. These women had more than two times the risk of breast cancer as women who had not taken any antibiotics.
The study found that women who took antibiotics for fewer days had less risk. Yet even these women had one-and-one-half times the risk of those who took none.
Doctor Stephen Taplin of the National Cancer Institute was among the leaders of the study. Doctor Taplin says the risk increased with all the kinds of antibiotics they studied.
Some cancer experts suggested that antibiotics could suppress "good" bacteria in the intestinal system. They say these bacteria help the body process foods that may help defend against disease. Or, they say, antibiotics might damage the immune system that protects the body against infection.
But Doctor Taplin and others say women who need more antibiotics may already have weakened immune systems. Another possibility is that the infections being treated may increase the risk of breast cancer. So the experts say more studies are needed before any direct link is made between antibiotics and breast cancer.
In many poor countries, pregnant women infected with the AIDS virus are given the drug nevirapine one time. This is during labor. Their babies also receive nevirapine once, during the first three days after they are born. Such treatment can cut in half the risk that the AIDS virus will spread from mother to baby.
But two studies have found that a single use of nevirapine may cause pregnant women to develop a resistance to it later. Scientists presented the studies in San Francisco, California, during a conference on anti-AIDS drugs.
In South Africa, scientists found that about forty percent of infected women who took the drug while giving birth later became resistant to it. Researchers in Thailand also found that mothers who received nevirapine were less likely to be helped by the drug if they developed AIDS. Researchers from France and the United States helped carry out the studies.
In richer countries, pregnant women with H-I-V receive a combination of anti-AIDS drugs throughout their pregnancies. Health officials say this lowers the chance that the mother will develop a resistance.
In developing nations, however, this method may not be economically possible. Combinations of anti-retroviral drugs to suppress the infection cost a lot. So the World Health Organization suggests the use of nevirapine alone. It says the two studies will not change this advice, at least for now.
Engineers are building a laboratory at the University of California at San Diego to study the effects of explosions. There are other blast simulators in the world that study the effects of explosions on buildings and other structures. But the engineers say this will be the first where scientists do not have to create real explosions.
The Jacobs School of Engineering is building the new laboratory at a field station several kilometers from the university. The blast simulator is expected to be in operation by early next year.
It will use a computer to control devices called hydraulic actuators. These are a series of heavy metal tubes. Water flows through them under pressure. The tubes are designed to extend quickly and strike an object with great force. This will recreate the shock waves produced by a bomb explosion.
The blast simulator will be connected to recording devices. The scientists will measure the effects of different size explosions on different kinds of structural materials. Bomb explosions move air with such force and speed that it pushes and pulls walls and other building supports.
The United States government is providing support for the project as part of anti-terrorism efforts. The structural engineers in San Diego have been researching ways to harden buildings against bomb attacks since nineteen-ninety-eight. That was the year bombs wrecked the American embassies in Tanzania and Kenya.
The Jacobs School of Engineering has done much work in the area of design to protect buildings against earthquakes. In fact, the blast simulator laboratory will be connected to another new laboratory.
The school has almost completed what it calls the world's first outdoor "shake table." Imagine a table that shakes -- and yet is big enough to hold a building several floors high. It will help scientists measure how buildings react to earthquakes.
For years, experts have been concerned about the future of the mountain gorillas of Africa. Disease, hunting, development and civil conflict all greatly reduced the population of these great apes. But researchers say the number of mountain gorillas in three national parks have increased by about seventeen-percent in recent years.
Mountain gorillas are one of the most endangered species in the world.
The International Gorilla Conservation Program led a study between September and October of last year. Teams of researchers studied mountain gorilla environments across the three national parks in the Virunga forests. The forests are on the borders of the Democratic Republic of Congo, Rwanda and Uganda.
The researchers recorded information about gorilla sleeping places and the gorillas they saw. They used that information to estimate the current population in those parks at three-hundred-eighty gorillas. That is fifty-six gorillas more than scientists had recorded in the last count in nineteen-eighty-nine.
War and hunting reduced the Virunga population to about two-hundred-sixty in the late nineteen-seventies. But national park officials and non-governmental organizations in the three countries have increased efforts in recent years to protect the great apes.
Researchers say three-hundred-twenty other mountain gorillas live in Uganda, in the Bwindi Impenetrable National Park. That is the only other place they are found. This means there at least seven-hundred mountain gorillas left in the wild.
Thirteen villages in northern Cambodia now have e-mail through a project that organizers hope other countries will copy. Energy from the sun powers computers in a group of schools and a medical center in Ratanakiri Province. Electronic mail is sent over the Internet, but with the help of what are called "motomen."
Each day, five people ride motorcycles into the villages to collect outgoing messages and bring incoming mail. The motorcycles are equipped with a computer to store the messages. The "motomen" return to the local capital where the information is sent by satellite to the Internet.
Students write to other villages. Local citizens can communicate with government officials, and receive newspaper stories by e-mail. Local doctors can get medical advice from far away. Organizers hope the system will also help local farmers sell their products online to the world market.
The group American Assistance for Cambodia organized the project. The technology is from a company in Massachusetts called First Mile Solutions.
SCIENCE IN THE NEWS was written by Caty Weaver, Jill Moss, Jerilyn Watson and Cynthia Kirk, who was also our producer. We had recording assistance from _________. I'm Bob Doughty. And I'm Sarah Long. Join us again next week for more news about science, in Special English, on the Voice of America.