Originally created 12/23/99

Capsules



Depressing statistic

Contrary to the view that some young people may start smoking in an attempt to alleviate depression, Johns Hopkins University researchers have found just the opposite: Smoking may lead to depression.

A five-year study of 1,731 youngsters starting at ages 8 and 9 found that smoking was linked to a modestly increased risk of depression, Li-Tzy Wu reported in the American Journal of Public Health.

Although the reason for the link is unknown, more research is needed to explore possible causes, given the detrimental effects of both smoking and depression on youngsters, Mr. Wu said.

Being at risk

An American's risk of having a stroke may be at least 20 percent higher than previously thought and as much as 50 percent higher.

A new assessment of stroke rates in the United States found that the number of people suffering strokes each year is 600,000 instead of 500,000, and the true figure may actually be closer to 750,000, G. Rhys Williams of the Knoll Pharmaceutical Co. in Mount Olive, N.J., reported in Stroke: Journal of the American Heart Association.

"As the elderly population continues to grow, the stroke burden in this country will also grow unless something is done to prevent strokes and to find better ways to treat and reduce the effects of stroke," he said.

Stroke is a major cause of adult disability and the third-leading cause of death. A daily aspirin tablet and blood-thinning drugs can reduce the risk of stroke, and so can reducing such risk factors as high blood pressure, cigarette smoking, diabetes, heart disease and excessive alcohol consumption.

Weighty issues

Being an overweight adult is associated with a number of health problems, and now asthma can be added to the list, according to researchers at Boston's Brigham and Women's Hospital.

A follow-up study of more than 85,000 women participating in the Nurses Health Study found that weight gain after age 18 significantly increases the risk of developing asthma, Dr. Carlos Camargo reported in the Archives of Internal Medicine.

"It is not a coincidence that as the prevalence of obesity rises in this country, so does the number of people with asthma," he said. "As a society, we need to pay more attention to the many health problems associated with obesity."

One out of three Americans is overweight, and an estimated 17 million people have asthma, including 5 million children.

The eyes have it

Large reptiles that swam in the sea had eyeballs at least 9 inches across, a new study suggests. The gigantic eyeballs probably helped the animals, known as an ichthyosaurs, see well in deep water.

Ichthyosaurs are a type of fish-shaped reptile that lived 90 million to 350 million years ago. Some species were a mere 12 feet long, while others were as long as 45 feet. Still, even for such big bodies, their eyeballs were champions, scientists report in the latest issue of the journal Nature.

Today, the largest eyes of any vertebrate belong to the blue whale, measuring 6 inches in diameter. But relative to the blue whale's giant body, which can be up to 100 feet long, the eyes are pretty puny. For its body length, a 12-foot ichthyosaur called Ophthalmosaurus had the largest eyes, measuring 9 inches. Other ichthyosaurs may have had eyes close to a foot in diameter.

Big eyes mean more cells in the retina to capture light.

Bacteria killer

A food preservative used for decades has given scientists fresh ideas about antibiotics.

Scientists are eager to find new antibiotics because so many bacteria have become resistant to the drugs.

The preservative, nisin, is naturally produced by a bacterium called Lactococcus lactis to kill competing bacteria. Because nisin is such a potent killer of bacteria, and because it's nontoxic to people, the food industry uses it to keep cheese and other milk products fresh.

In the latest issue of the journal Science, researchers from the Netherlands and Germany describe how nisin kills bacteria. The researchers found that nisin latches on to a fatty component of bacteria's outer cell walls. Nisin also creates a pore in the cell wall, causing the bacterium's contents to leak out.