Michael Bloomberg, the billionaire who has made reducing smoking one of his signature causes as mayor of New York City, is committing $220 million to his charity to go toward reducing tobacco use in countries that are home to millions of smokers.

He announced his four-year commitment to Bloomberg Philanthropies at the 15th World Conference on Tobacco or Health in Singapore on Thursday. The new commitment will bring the total amount he has directed to his eponymous charity to over $600 million for anti-smoking efforts since 2007.

Brazil said Wednesday it has temporarily suspended the import of breast implants pending quality control tests in the wake of last December's health scare over defective French-made implants.

A spokeswoman for the National Health Surveillance Agency(ANVISA) said a resolution had been approved to insist that the implants be allowed into the country only after quality certification.

Allergy season has come early and hit with a wheezing vengeance in parts of the South and Midwest this year, thanks largely to an unusually warm winter. Abundant pollen is causing watery eyes, sniffles and sneezing.

Doctors say the spring misery stretches from Mississippi to Ohio and from Georgia to Texas, where drought conditions have exacerbated the problem. Forecasters and allergists blame the unseasonably warm weather, and few cold snaps, for causing plants to bloom weeks early and release the allergy-causing particles.

Identifying lines on a color-coded metro map is tricky for those who can't see some colors. Choosing clothes or telling a green from a red apple can be just as baffling.

But the pioneering work of a designer in the northern Portuguese city of Porto means such quandaries may soon pose less of a challenge for the color blind.

Too often, people pass a cardiac checkup only to collapse with a heart attack days later. Now scientists have found a clue that one day may help doctors determine if a heart attack is imminent, in hopes of preventing it.

Most heart attacks happen when fatty deposits in an artery burst open, and a blood clot then forms to seal the break. If the clot is too big, it blocks off blood flow.

Greece will issue free condoms and syringes to heroin addicts to halt an alarming rise in new HIV cases, the health ministry said on Tuesday.

"There is an imperative need for immediate action to limit the spread of infection," deputy health minister Michalis Timosidis said in a parliamentary document.

Few people want to be wide awake during their colonoscopy exams, but new research suggests too many are getting extra sedation treatment, costing as much as $1 billion yearly in potentially needless services.

Use of anesthesiologists to monitor sedation during colonoscopies and other digestive imaging tests has more than doubled in recent years, and they're used most often for low-risk patients who typically don't need the extra help, the study authors said.

A drug designed to treat nervous spasms has cleared an important early test in a project to see whether it can also cure alcoholism, French doctors said on Tuesday.

Baclofen -- the lab name for a medication branded as Kemstro, Lioresal and Gablofen -- was successful in a preliminary test among a small group of alcoholics, a result that opens the way to formal clinical trials, they said.

Researchers on Tuesday unveiled a blueprint to guide the next steps in the hunt for a more effective vaccine against tuberculosis as the world's most advanced clinical trial nears its end.

The plan is part of a global push aimed at giving TB research the same high profile -- and funding -- that goes to diseases like AIDS.

The anti-inflammatory drug ibuprofen can reduce acute altitude sickness suffered by a quarter of the millions of Americans who travel to the mountains to ski or hike, according to a clinical study published Tuesday.

Grant Lipman, the Stanford University researcher who led the study, described altitude sickness as being like "a really nasty hangover."