A drug discovered nearly four years ago that builds muscles in lazy mice may also prevent heatstroke, according to lab research reported on Sunday.

If further tests work out, the compound could help athletes or soldiers who are so sensitive to heat that they could die from exertion on a hot day, its authors say.

Swiss pharmaceutical firm Novartis said Sunday it was recalling four different products sold over the counter in the United States over reports of a malfunction at one of its plants.

The affected drugs are Excedrin, NoDoz, Bufferin and Gas-X Prevention, Novartis Consumer Health (NCH) said in a statement.

Belgian surgeons have successfully performed the country's first-ever face transplant, the 19th in the world, doctors announced Saturday.

Officials at the University Hospital of Ghent said a team of 65 surgeons and medical staff had performed the 20-hour operation a week earlier on a Belgian man with a severely mutilated face.

Germany and the Czech Republic advised women Friday to have potentially faulty breast implants made by French firm PIP removed, but Britain said it was not convinced of the need.

Germany's Federal Institute for Medications and Medical Products (BfArM) recommended that implants made by the firm at the heart of the scandal should be removed "as a precautionary measure".

Medical tests performed after Argentine President Cristina Kirchner had her thyroid removed in a three and a half hour operation found that she did not have cancer as initially believed, her spokesman said Saturday.

A final examination of the tissue removed "confirmed the presence of nodules in both lobes of the president's thyroid gland, but it ruled out the presence of cancer cells, thus modifying the initial diagnosis," Kirchner's spokesman Alfredo Scoccimarro said.

Nearly 7,000 people have now died from cholera in Haiti in an epidemic which has become one of the worst of recent decades, a top health official said Friday.

Jon Kim Andrus, deputy director of the Pan American Health Organization, said that as of December, on top of the deaths, the Haitian government had reported more than 520,000 cholera cases with 200 new sufferers appearing each day.

Developed for troops serving on glaciers high in the Himalayas, the non-flushing "bio-digester" toilet made by India's top defense research body is now being offered to companies and poorer states.

It is one of 200 technologies produced by the Defense Research and Development Organization (DRDO) identified as for sale via the Federation of Indian Chambers of Commerce and Industry (FICCI).

About 200 million people around the world use illicit drugs, according to a study published on Friday in The Lancet.

It estimates that in 2009 between 149 and 271 million people used an illegal drug.

Cognitive skills can start to fall from the age of 45, not from around the age of 60 as is commonly thought, according to research published on Friday by the British Medical Journal (BMJ).

Researchers led by Archana Singh-Manoux from the Centre for Research in Epidemiology and Population Health in France and University College London observed 5,198 men and 2,192 women over a 10-year period from 1997.

Advances in fertility treatment and a trend toward later-life childbirth are fueling a boom in twins in the United States, where one in 30 babies is a twin, according to U.S. data out Wednesday.

The number of twins doubled in 2009 compared to 1980, rising from 68,339 to over 137,000 births, said the National Center for Health Statistics' data brief on three decades of twin births in the United States.