Vitamins and cancer
Researchers have found a mechanism that might explain a puzzling association between beta carotene and lung cancer in heavy smokers.
Antioxidants such as beta carotene and vitamins E and C are thought to reduce the risk of cancer and other diseases by scavenging for dangerous molecules called free radicals. However, recent studies suggest that heavy smokers who take beta carotene actually increase the risk of a lung malignancy.
The problem is not so much the presence of beta carotene but the absence of vitamin C, researchers from England and Germany reported last week in the Journal of the American Chemical Society.
The scientists found that beta carotene normally enhances the antioxidant effect of vitamins C and E. However, smoking depletes the body's supply of these vitamins. Without vitamin C, a potentially harmful form of beta carotene may accumulate.
Helmets save lives
Most of the 247 deaths and 140,000 injuries from traumatic brain injury suffered by children and adolescents in bicycle accidents could be prevented, according to the Centers for Disease Control and Prevention.
Wearing helmets could prevent 184 deaths and 116,000 head injuries annually, Dr. Daniel M. Sosin reported in the journal Pediatrics.
Helmets also need to be changed to fit children younger than 6, who have the highest proportion of head injuries, and to prevent the 19,000 mouth and chin injuries that occur each year, he said.
Frogs have own gig
An earless species of Panamanian frog that uses hand signals to ward off competing male frogs also calls out to them and his calls are returned, which has puzzled researchers.
New studies from Ohio State University suggest that the frogs pick up sound waves through their lungs, which are very close to the surface of their bodies. But how the lungs transmit the signals to the inner ears of the frogs still isn't understood. When male frogs fight over mates, they jump atop one another and wave vigorously until one stops waving to signal defeat, but no one really gets hurt much.
"Most people tend to think that frogs are pretty simplistic," said Thomas Hetherington, an Ohio State professor of zoology, "but when we looked at them closely we found them engaged in a long series of very subtle behaviors."
Gene caught in act
Knowing the enemy has paid off for some California cancer researchers.
Scientists from Stanford University have found a gene that they believe can contribute to the progression of breast cancer.
In a recent issue of the journal Cell, a research team led by Stanley Cohen reported that a gene called "TSG101" is abnormal in about half of the breast tumors tested.
While much attention has focused lately on inherited genes that can contribute to breast cancer, "TSG101" was found to be abnormal in cases that arose without any clear family pattern. These sporadic cases account for most breast cancers.