Drugs used to treat epileptic seizures can raise suicide risks, but not enough to deserve the strongest warning labels available, a government panel of experts said Thursday.

Advisers to the Food and Drug Administration voted 14-4 against adding a "black box" warning about the risks of suicidal tendencies to all anti-seizure drugs.

The FDA earlier this week announced plans to add boxed warnings to epilepsy drugs, in light of an analysis of suicidal tendencies of more than 43,000 patients enrolled in 200 studies. The panel vote makes it less likely that blockbuster drugs from GlaxoSmithKline, Pfizer Inc., Merck & Co. Inc. and others, will be forced to carry the FDA's sternest warning.

The agency often follows its panels' advice, though it is not required to do so.

More than 10 million Americans take the 25 medications discussed at the FDA's meeting. Besides epilepsy, they are also used for migraines, certain nerve-pain disorders and psychiatric diseases such as bipolar disorder.

Melanoma rate soars for young women

Increasing numbers of younger women continue to be diagnosed with the most dangerous form of skin cancer even as the rate of new cases has leveled off in younger men, federal health officials reported Thursday.

An analysis of government cancer statistics from 1973 to 2004 found that the rate of new melanoma cases in younger women had jumped 50 percent since 1980 but did not increase for younger men in that period.

"It's worrying," said Mark Purdue, a research fellow at the National Cancer Institute, who led the analysis published in the Journal of Investigative Dermatology. "What we are seeing in young adults right now could foretell a much larger number of melanoma cases in older women."

About 62,000 melanoma cases are diagnosed each year in the United States, and more than 8,400 people die from the disease, according to the Atlanta-based American Cancer Society.

Study: Secondhand smoke in decline

Nearly half of nonsmoking Americans are still breathing in cigarette fumes, but the percentage has declined dramatically since the early 1990s, according to a government study released Thursday.

A main reason for the decline in secondhand smoke is the growing number of laws and policies that ban smoking in workplaces, bars, restaurants and public places, said researchers with the Centers for Disease Control and Prevention in Atlanta.

Another factor is the drop in the number of adult smokers: It has now inched below 20 percent, according to 2007 CDC data.

The new study found about 46 percent of nonsmokers had signs of nicotine in their blood in tests done from 1999 through 2004.

That was a steep drop from 84 percent when similar tests were done in the late 1980s and early 1990s.

Astronauts dare perilous spacewalk

In a daring spacewalk, two space station astronauts cut into the insulation of their descent capsule and removed an explosive bolt that could have blown off their hands with firecracker force. Russian spacewalkers Sergei Volkov and Oleg Kononenko managed, in the end, to safely disconnect the bolt from the Soyuz capsule that will be their ride home in October.

The past two Soyuz descents have been steep, off-course and bone-jarring, and the Russian Space Agency wants to avoid the problem.

The lone American on board, Gregory Chamitoff, was inside the Soyuz for the entire six-hour spacewalk in case an emergency required the two Russians to join him in the capsule.

NASA has a keen interest in the Russian-built Soyuz capsules because they sometimes transport Americans to and from the space station, and they also serve as lifeboats. Once the space shuttles are retired in 2010, the Soyuz will be the sole means of human space transportation until 2015, when America's new rocket ship starts carrying crews.

Autism research shows some genes turned 'off'

New research suggests that some cases of autism arise from defects in genes that can be turned on or off by mental activity, a finding that sheds light on the devastating condition and might eventually lead to strategies to treat it.

The findings are drawn from gene scans of about a hundred Middle Eastern families in which autism is unusually common. The disorder is marked by social isolation, speech problems, and strange repetitive activities.

The study, done by a large international team and reported today in the journal Science, adds to the growing evidence that autism may result from problems in the immensely complicated process by which some networks of brain cells expand and many others die back in the first few years after birth.

Species in coral reefs face risk of extinction

Nearly one-third of the animals that build the most massive and elaborate structures in coral reefs face elevated risk of extinction from global warming and various local problems, an international group of scientists reported. The worldwide assessment of more than 700 species of corals showed that 32.8 percent are threatened with extinction. The results were presented at the International Coral Reef Symposium in Fort Lauderdale, Fla., where nearly 3,000 scientists and managers are meeting to figure out how to save the world's reefs.

Caviar lovers crave paddlefish eggs, but at some risk

Severe fishing restrictions in the Caspian Sea have led caviar fans to seek domestic alternatives to the prized eggs of Russian sturgeon, and many connoisseurs rank the homely paddlefish —- native to the Mississippi River and its tributaries —- high on their lists of suitable alternatives.

But as demand for paddlefish caviar has grown, health officials have become uneasy about a variety of toxins found in the eggs, including mercury, chlordane and cancer-causing polychlorinated biphenyls, or PCBs. Advocates, however, say the level of contaminants is below federal safety standards and that most consumers don't eat enough of it to suffer any ill effects.

Indiana, Kentucky and Tennessee have issued advisories warning consumers to limit their consumption of paddlefish caviar from portions of the Mississippi, Ohio and Tennessee rivers. Yet the U.S. Food and Drug Administration and the Department of Agriculture do not require companies to list the river of origin on their labels. "If I were a consumer of that product, which I'm not, but if I were, I would want to know," said Paul Beiriger, a U.S. Fish and Wildlife Service agent.