SCIENCE IN THE NEWS #2075 - DigestBy StaffThis is Bob Doughty.And this is Ray Freeman with SCIENCE IN THE NEWS, a VOA Special English program about recent developments in Science. Today, we tell about a new list of substances that may cause cancer. And we tell about efforts to prevent two rare animals from disappearing.
American health officials have announced changes in a government report about what causes cancer. The National Institute for Environmental Health Sciences announced the changes last month in a report.
The new report removes the food sweetener called saccharin from the list of suspected cancer-causing substances. However, several other substances were added.
Saccharin is the sweetener used in a substitute for sugar called Sweet n Low. Saccharin also is found in many other food products instead of sugar. Saccharin had been listed as a suspected cause of cancer since Nineteen-Eighty-One. An earlier Canadian study showed that it caused bladder cancer in laboratory animals.Kenneth Olden is director of the National Institute for Environmental Health Sciences. He says it was wise to consider saccharin a likely cause of cancer in humans twenty years ago. Doctor Olden says an improvement in scientific understanding led to the decision to drop the sweetener from the list. He says studies now show that the causes of the cancers in the animals are different from those in humans.
Some public interest groups oppose the decision to remove saccharin from the list of cancer-causing substances. They say the government's decision will lead to increased use of the sweetener.
The government report identifies two-hundred-eighteen substances that may cause cancer. The list includes alcoholic drinks, too much sunshine, smoke from tobacco products and smokeless tobacco.
American health officials also warned about the dangers of what they call second-hand smoke. They say some studies have shown that non-smokers who work or live with people who smoke cigarettes face an increased risk of developing lung cancer.
Also included on the list were substances produced during the process of mining and in the manufacture of alcohol, lead batteries, soap and rubber. A drug that is used to treat one kind of cancer also was included in the list of cancer-causing substances. Tamoxifen fights breast cancer. But it increases the risk of cancer of the uterus.
((MUSIC BRIDGE))You are listening to the Special English program SCIENCE IN THE NEWS on VOA. This is Ray Freeman with Bob Doughty in Washington.
Chinese experts are trying several new methods to help giant pandas have babies. The experts are working to increase the panda population because the animal is threatened with disappearing from earth. Only about one-thousand giant pandas live in the wild. An official Chinese newspaper says some giant pandas in research centers are receiving the drug Viagra. Viagra is given to human males who are unable to perform normal sexual activities. Viagra helps by increasing the flow of blood to the male sex organ.
The Wen Hui Daily newspaper in Shanghai reported about pandas taking Viagra. It says a male panda can perform the sex act for only about thirty seconds at a time. Some animal experts believe a male panda would have a better chance of making a female pregnant if Viagra could extend that time.But another official government newspaper, the Beijing Youth Daily, says a major panda research center is refusing free Viagra from drug companies. The Wolong center in Sichuan Province also has refused Chinese medicine for the same purpose. Center Director Zhang Hemin says research there shows that most male pandas' sexual performance did not improve with either Viagra or the Chinese medicine. He says he believes the problem is that many pandas do not know how to mate.
So the center is showing male pandas special films of pandas mating. Zhang Hemin reports an improvement in the sexual performance of male pandas after watching the films. Mr. Zhang says his center also provides the pandas with improved food and living conditions.
Scientists are trying other ways to increase the number of pandas in the world. They are experimenting with the process of cloning to produce exact copies of the animals. Last year, Chinese scientists announced they had produced a giant panda embryo using an egg from a rabbit. However, no live panda has yet been produced from the process.Many zoos around the world continue to seek pandas from China. The zoos want to help the pandas reproduce. Recently, China agreed to lend two young pandas to the National Zoo in Washington, D-C for ten years. The National Zoo will pay China's Wildlife Conservation Association one-million dollars each year for the ten years. The money will support China's national project for the protection of giant pandas. Zoo officials hope the male and female pandas will mate and have babies. China will own the pandas and any babies they produce.
In Nineteen-Seventy-Two, the National Zoo received two pandas from China as a gift. But the pandas died without producing any babies that lived. Most pandas in zoos have not reproduced. Or they have given birth to babies that soon die.
((MUSIC BRIDGE))A British wildlife organization says the recent birth of three young lions is a major step toward saving the rare Barbary lion from disappearing.
The International Barbary Lion Project praised the births. Two of the lion cubs were born at Rabat Zoo in Morocco. A third was born at Port Lympne, in Kent, England.
Kay Hill directs the Barbary Project at WildLink International in Essex, England. WildLink is a group that collects money for wildlife protection. It is working with several other organizations to help the rare Barbary lions reproduce and to put the animals back into the wild.
Mizz Hill says the project decided to take the action at this time because there are only a few real Barbaries left in the world. And she said some of those lions are getting old. At one time, scientists thought the Barbaries had disappeared. A scientific book of animals removed the Barbary from its official list of living creatures. It did so after a hunter was believed to have killed the last known Barbary in Morocco in the Nineteen-Twenties.The International Barbary Lion Project includes only lions known to have come from what is called the King's Collection at the Rabat Zoo. Project officials say these lions are the only true known Barbaries in the world. The officials express concern about owners of zoo parks and circuses who claim their lions are Barbaries. The Barbary Lion Project says these lions are being incorrectly identified because only the lions' appearance is being considered. Barbaries have heavy, dark fur that covers the length of the underside of their bodies. This mane runs from the back of the neck down under to their chests and stomachs. The experts say some lions are identified as Barbaries because of these manes. However, five other kinds of lions also can have this mane.Experts the only way scientists can identify a true Barbary is by its genetic material, DNA. Scientists are taking DNA from bones of Barbary lions in museums. They are comparing it with the DNA of possible Barbaries. Scientists are testing the DNA at Oxford University in Britain.
The three lion cubs still must be scientifically confirmed to be Barbaries. Scientists hope they will produce more Barbary lions. The next step would be to release some of these animals in the Atlas Mountains of Morocco. Two years ago Mizz Hill made plans with the Moroccan government to use more than one-hundred-thousand hectares for a home for the Barbaries.
This SCIENCE IN THE NEWS program was written by George Grow and Jerilyn Watson. It was produced by George Grow. This is Ray Freeman.And this is Bob Doughty. Join us again next week for more news about science in Special English on the Voice of America.