Health & Science

A clue to the cause of Alzheimer’s

A rare gene mutation that protects people from getting Alzheimer’s could help steer researchers toward drugs that slow the disease’s devastating progress. Icelandic researchers tested 1,795 Icelanders and found that about 1 percent of them have a genetic variation that slows the formation of the protein beta amyloid, which is known to build up as plaque in the brains of Alzheimer’s patients. People with the mutation have 40 percent less beta amyloid in their brains and are 81 percent less likely to develop Alzheimer’s after age 85 than those without the mutation, the study found. “It confers extraordinarily strong protection,” neurologist Kari Stefansson tells Reuters.com. There’s little point in testing for the protective variation, which is thought to be present in only 1 in 10,000 North Americans. The finding’s real importance is that it shows a crucial link between beta amyloid formation and Alzheimer’s, offering encouragement for efforts to develop drugs aimed at stopping the gummy plaque from forming, in the hope of preventing or slowing the onset of the disease. “This provides some of the strongest evidence ever that amyloid is the right target in Alzheimer’s,” said researcher Sam Gandy of Mount Sinai School of Medicine in New York.

The growing coral-reef crisis

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Higher levels of carbon dioxide in the atmosphere are boosting the acidity of oceans and posing a grave threat to the world’s coral reefs, the Associated Press reports. The problem is so dire that experts are now calling acidification global warming’s “equally evil twin,” says Jane Lubchenco, the chief of the National Oceanic and Atmospheric Administration. The more carbon dioxide oceans absorb from the air, the more acid is produced. Previous studies suggested that acidity would be diluted as it circulated evenly throughout the ocean. But researchers have now discovered that acidity tends to concentrate in shallow waters, where coral reefs protect coastlines from erosion and provide one of the ocean’s richest ecosystems. The acid dissolves the reefs’ calcium carbonate branches and prevents new ones from forming. It also eats away at the shells of bivalves, such as oysters, and even scrambles the brains of fish that flourish in the reef environment, making it harder for them to navigate and avoid predators. The higher acidity is “really hammering reefs around the world,” Lubchenco says, reverberating through the marine food chain and making coastlines more vulnerable. “It’s a very serious situation.”

A dark-matter discovery

For the first time, astronomers have detected one of the thin strands of “dark matter’’ believed to bind together the galaxies of the universe. Dark matter is a mysterious substance whose existence can only be inferred. Physicists have calculated that it makes up some 83 percent of the universe, but since it doesn’t emit or absorb light, it can’t be spotted with traditional telescopes. Researchers can identify large clumps of it by observing how its gravity distorts light from nearby galaxies, but the dark matter filaments thought to form a kind of cosmic scaffolding for the universe have previously been too wispy to see. Now, though, researchers at the University Observatory Munich in Germany have uncovered two galaxy clusters, some 2.7 billion light-years away, that lie at just the right angle from Earth to allow researchers to precisely observe the space between them. Using a phenomenon called gravitational lensing, they analyzed the light from 40,000 background galaxies as it passed between Abell 222 and Abell 223 and found that an invisible mass—most likely dark matter—was bending it. The finding is important proof that dark matter exists and that it helps to structure the universe, study author Jörg Dietrich tells Space.com. “It’s a confirmation people didn’t think was possible at this point,” he says.

How pets benefit babies

Living with a dog or a cat may bolster babies’ health. After surveying the parents of nearly 400 infants over the course of a year, Finnish researchers found that children who lived with a dog were 31 percent more likely to be in good health than those who didn’t. They were also 44 percent less likely to have developed an ear infection and 29 percent less likely to have needed antibiotics. Owning a cat offered similar, though less significant, benefits. The more time pets spent outdoors, the healthier the babies that lived with them were, which suggests that dogs and other pets may track in dirt and germs from outdoors that “stimulate the immune system” of babies “to do a better job of fighting off infection,” Danelle Fisher, a pediatrician at St. John’s Health Center, tells the Los Angeles Times. Previous studies have shown that babies who are exposed to pets and dust are less likely to develop allergies and asthma.