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WASHINGTON, July 20 (Xinhua) -- The loss of a protein that coats sperm may explain a significant proportion of infertility in men worldwide, according to a study by an international team of researchers led by University of California Davis.A paper describing the work was published Wednesday in the journal Science Translational Medicine. The research could open up new ways to screen and treat couples for infertility.The gene DEFB126 encodes a protein called Beta Defensin 126, which coats the surface of sperm and helps it penetrate cervical mucus in the female. A survey of samples from the U.S., Britain and China showed that as many as a quarter of men worldwide carry two copies of the defective gene.In the new study, researchers found that men with a muted DEFB126 lack Beta Defensin 126, making it much more difficult for sperm to swim through the mucus and eventually join with an egg.Examining 500 newly married Chinese couples, researchers found that the lack of Beta Defensin 126 in men with the DEFB126 mutation lowered fertility (even among men that did not display other deficiencies usually associated with infertility, like inadequate semen volume and low sperm motility). Wives of men with the Beta Defensin 126 variant were significantly less likely to become pregnant than were other couples, and 30 percent less likely to have a birth.This genetic variation in DEFB126 likely accounts for many unexplained cases of infertility, researchers say. They hope next to work with a major infertility program in the U.S. to further explore the role of the mutation.

THE HAGUE, June 1(Xinhua) -- Five people in the Netherlands have been sickened with an unusual strain of the E. coli bacteria, the institute for public health (RIVM) reported Wednesday.Of the five patients, four also suffered from intestinal problems and renal failure. The five who are infected all had recently been in Germany.The patients were infected with enterohaemorrhagic E.coli, or EHEC, a particularly deadly strain of the common bacteria found in the digestive systems of cows, humans and other mammals.The outbreak has hit at least eight European countries but virtually all of the sick people either live in Germany or recently traveled there.Medical authorities appeared no closer to discovering either the source of the infection or the mystery at the heart of the outbreak: why the unusual strain of the E. coli bacteria appears to be causing so many cases of hemolytic uremic syndrome, which attacks the kidneys and can cause seizures, strokes and comas.Earlier this week German researchers showed that Dutch cucumbers were not the cause of the contamination."It is essential to quickly find the source, as long as that is not found, the contamination can spread. It's a very aggressive bacteria and many people are seriously ill," a RIVM spokesman said.

LOS ANGELES, May 30 (Xinhua) -- The American Academy of Pediatrics (AAP) warned on Monday that children should keep away from energy drinks which may be dangerous for minors.The AAP urged young children and teens to avoid energy drinks entirely, saying routine consumption of sports drinks should be limited or eliminated.Energy drinks include such popular brands as Red Bull, AMP and Rockstar, the AAP said in a report.These drinks, the report said, tend to be heavily caffeinated, potentially having several times the level of caffeine found in a cup of coffee.In addition, manufacturers often add sugar and herbal stimulants such as guarana and taurine to the drinks, which are popular among kids, according to the report."There's no place for energy drinks for kids," said report co-author Dr. Marcie Beth Schneider, an adolescent physician in Greenwich, Connecticut. "There's a place for sports drinks, but that place is very specific."The caffeine in energy drinks can lead to high blood pressure, high heart rate and insomnia, she said.The other ingredients can boost the power of the caffeine, she said, adding that the drinks will have a greater effect on children because they're smaller than adults."Kids don't need to have this," she said. "This is not something they should be drinking."Schneider declined to identify any energy drinks that may be better than others for kids who insist on drinking them. If kids use energy drinks because they're tired, she said, they should get more rest instead of chugging caffeine.Half of the nation's 5,448 reported caffeine overdoses in 2007 were in people under age 19, although it's not known how many of the cases were the result of energy drink consumption, according to statistics provided by the AAP.

MOSCOW, Aug. 3 (Xinhua) -- Two Russian cosmonauts manually launched a mini satellite from the International Space Station ( ISS) during a six-hour spacewalk Wednesday, said the Mission Control center near Moscow.Sergei Volkov and Alexander Samokutyayev, who started the spacewalk with a 20-minute delay, found the 30-kg Kedr has lost one of its two antennas during its delivery to the ISS in January. After consulting with the Mission Control, they have decided to launch the device anyway, Interfax news agency reported.The Kedr satellite, which was made by Russian students, was created to transmit from the orbit greetings in 15 languages about the 50th anniversary of Yuri Gagarin's first space flight. It could also photograph the Earth and re-transmit information from the ISS equipment.During the spacewalk, the cosmonauts were expected to install new stream video equipment on the station's outer surface, and to take pictures holding photos of the founders of Russian space explorations, including Konstantin Tsiolkovski, Sergei Korolyov and Yuri Gagarin.