Scientists have pinpointed a protein that helps explain why the elderly frequently have to get up in the night to urinate, a problem that can badly interfere with sleep.

Deficient levels of protein called connexin43 trick the bladder into believing that it is full, which sends a "must urinate" warning to the brain, they report on Tuesday in the journal Nature Communications.

Most clinical trials for cancer, heart disease and mental health are too small to offer adequate medical evidence, said a review of the U.S. database of such studies released on Tuesday.

The analysis in the Journal of the American Medical Association was led by experts at Duke University in collaboration with the U.S. Food and Drug Administration.

Facebook on Tuesday unveiled an initiative to use the vast social network to connect organ donors with people who need life-saving transplants.

Facebook founder Mark Zuckerberg made the announcement and became one of the first Facebook users to sign up on the social network to be an organ donor.

A cheap, simple device widely used to monitor blood oxygen can help save newborn babies with congenital heart defects, a study in The Lancet determined on Wednesday.

Congenital heart flaws account for between three and 7.5 percent of all infant deaths, but surgery greatly improves the chances of survival, especially if the problem is detected at the earliest stages.

McDonald's is a sponsor for the London Olympics — and a British doctors' group says that's sending the wrong message in a country with ballooning obesity.

Big Macs, fries and milkshakes will be part of McDonald's exclusively branded menu at the Olympics and the fast-food giant will soon be opening its largest franchise in the world, a two-story cathedral-like restaurant that seats 1,500 customers, at London's Olympic Park. McDonald's will be the only restaurateur allowed to sell brand-name food at the Games and there will also be a separate McDonald's within the Athletes Village — in addition to three others at the Olympic Park.

When pregnant women are exposed to moderate levels of a common pesticide, their children may experience lasting changes in brain structure linked to lower intelligence, a U.S. study said Monday.

The study in the Proceedings of the National Academy of Sciences examined New York City pregnant mothers who were tested for exposure to chlorpyrifos, or CPF, which is widely used for pest control in farms and public spaces.

Prescription painkiller abuse among mothers-to-be has driven up the rate of babies born in the United States with opiate addiction almost threefold in a decade, said a U.S. study on Monday.

The study published in the Journal of the American Medical Association showed a five-fold increase in maternal use of painkillers from 2000 to 2009, rising from 1.19 cases per 1,000 births to 5.63 per 1,000 annually.

New research sends a stark warning to overweight teens: If you develop diabetes, you'll have a very tough time keeping it under control.

A major study, released Sunday, tested several ways to manage blood sugar in teens newly diagnosed with diabetes and found that nearly half of them failed within a few years and 1 in 5 suffered serious complications. The results spell trouble for a nation facing rising rates of "diabesity" — Type 2 diabetes brought on by obesity.

Coca-Cola has been ordered to temporarily halt production at a bottling plant in northern China, after media reports of chlorine in its products, according to a government statement.

Shanxi province ordered an investigation after reports that a batch of drinks contained water with chlorine, the province's quality bureau said in a statement at the weekend.

Scientists have identified a gene that slows the spread of pancreatic cancer tumors, paving the way for targeted treatment of one of the deadliest forms of the disease, said a paper published Sunday.

After discovering the gene dubbed USP9X at work in a study of pancreatic cancer in mice, the international research team found it also played a role in humans.