Researchers are gaining insight into why a common bacterium can sometimes lead to a dangerous heart infection in children. The bacterium, group A Streptococcus, causes acute rheumatic fever. This is the most common infectious cause of childhood heart disease. GAS bacteria are relatively common. They cause diseases ranging from sore throats to toxic shock and "flesh-eating" disease. Scientists don't know why different GAS strains invade different parts of the body. They don't know whether rheumatic fever outbreaks are caused by genetically similar bacteria or new strains. To find out, they isolated GAS bacteria. The scientists from the National Institute of Allergy and Infectious Diseases found several genes to those bacteria. Their discovery also reveals that two rheumatic fever outbreaks occurring 12 years apart in the area around Salt Lake City, Utah, were caused by virtually identical GAS strains. "We have made enormous strides in understanding the biology of infectious diseases, yet much remains to be learned about relatively common bacteria like group A Streptococcus," said Dr. Anthony Fauci, NIAID director. "This research reveals some of the secrets of group A Strep and is a major accomplishment in our quest to understand an important childhood disease."
BLOOD TEST TO DIAGNOSE ALZHEIMER'S CHANGES
Researchers have identified Alzheimer's-like changes in mice through a blood test. The test was developed by scientists at Washington University School of Medicine in St. Louis and Eli Lilly and Company. It predicts the amount of amyloid plaque in an animal's brain. This is a hallmark of Alzheimer's disease. To date, the only way to diagnose the disease in humans is by examining a person's brain after death. "We don't know if this finding in mice will apply to humans," said Dr. David Holtzman, the Charlotte and Paul Hagemann Associate Professor of Neurology and associate professor of molecular biology and pharmacology. "If it does, it has the potential to provide a non-invasive means of detecting Alzheimer's pathology even before clinical symptoms appear."
IMPLANTABLE HEART CUTS DEATHS
Of the thousands of heart attack survivors each year, half remain at risk for sudden death. In this group, an implanted cardioverter defibrillator can cut the death rate by 31 percent, a study shows. The four-year study of 1,232 patients at 76 sites around the world, reported at a meeting of the American College of Cardiology in Atlanta and in The New England Journal of Medicine, showed the preventive value of the device, also called ICD, said Dr. Arthur Moss, professor of medicine at the University of Rochester Medical Center. The device, about the size of a pager, is surgically implanted in the chest under local anesthesia. It detects irregular and potentially fatal heartbeats and shocks the heart back into a normal rhythm. Introduced 20 years ago, ICDs had been prescribed only for a small group of patients who had survived a cardiac arrest. The new study "is an important and major contribution to the field as it sets new standards for therapy to save lives and improve survival," Moss said. "Currently there is no other preventive treatment for people at risk of dying suddenly from heart rhythm disorders."
BLOOD PROTEINS ACT AS ANTIFREEZE
Scientists studying fish in the icy seas around the North Pole and Antarctica have found how they survive at temperatures that would freeze most animals: blood proteins that act as a natural antifreeze. University of California, Davis, scientists are closing in on how the proteins work. The research could lead to safer storage of food or blood products. It may also help scientists understand how mineral deposits can cause kidney stones and heart disease. The proteins, called antifreeze glycoproteins, are long, floppy and covered in sugar molecules that interact with water. Using nuclear magnetic resonance and infrared spectroscopy, Nelly Tsvetkova and colleagues in the Biostabilization Laboratory have found that even in ice as cold as minus 60 degrees Celsius (minus 76 degrees Fahrenheit), the proteins are surrounded with a shell of liquid water and are constantly moving and changing shape. The antifreeze proteins also stabilize cell membranes during chilling, said John Crowe, head of the biostabilization group.
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