Health & Science
A possible cure for AIDS?; An Ice Age find in Alaska; Repairing the heart; How sea turtles navigate
A possible cure for AIDS?Using the rare natural immunity some people have to HIV as a model, scientists have devised a promising new approach toward a cure for AIDS. Their starting point was the celebrated case of an American AIDS patient in Berlin whose HIV infection disappeared after he received a blood transfusion. The donor’s T cells, researchers discovered, lacked the protein receptors that HIV needs to latch onto to kill the cells, making them uniquely immune to the virus. Now scientists at Sangamo BioSciences in California have developed a treatment that replicates that positive genetic trait—which occurs in less than 1 percent of the population—by slicing out the responsible gene from strands of DNA. When they tested the treatment on blood drawn from six men with HIV, it deleted the receptors from many of the cells. And when those HIV-immune cells were injected back into the patients, they seemed to thrive. “This is elegant work, scientifically very sound,” Anthony Fauci, a prominent AIDS researcher at the National Institutes of Health, tells The Philadelphia Inquirer. While experts warn that much more testing is needed, researcher John Rossi says the results are “a huge step” toward one day wiping out AIDS. “The idea is if you take away cells the virus can infect, you can cure the disease.”
An Ice Age find in AlaskaThe bones of a 3-year-old child discovered in central Alaska are yielding new insights into the culture of the Ice Age people who migrated from Asia over the Bering Land Bridge. Researchers believe the child—whose remains are the oldest ever unearthed in Arctic or subarctic North America—was cremated 11,500 years ago in the hearth of a home that was then abandoned, perhaps to serve as a crypt. Having previously identified temporary campsites from the era, scientists had thought the people who used them were nomadic hunters. But the child’s dwelling had been dug into the ground, and there were hundreds of salmon bones nearby, suggesting that its residents had stayed put to fish during a whole summer, much as later Alaska natives did. “Nothing remotely similar has been found from this time period,” University of Alaska Fairbanks anthropologist Ben Potter tells NPR.org, “so it’s quite overwhelming.” Potter and his colleagues believe the child’s family could have been part of the last cultural group to cross the land bridge before it was submerged, roughly 500 years later. They now hope DNA analysis of the child’s remains will reveal his or her genetic relationship to modern native populations, unlocking clues to how the earliest Americans spread across the continent.
Repairing the heartNewborn mice can completely regenerate damaged heart tissue, a new study shows, revealing an ability never before seen in mammals. Scientists knew that certain fish and amphibian species are able to regrow injured tissue. But when researchers from the University of Texas Southwestern Medical Center removed 15 percent of the heart tissue in one-day-old mice, they were surprised to see the cells grow back in only three weeks. The mice regained full heart function, and showed none of the scarring that often disables humans who survive comparable harm, such as from a heart attack. The catch? The capacity for self-repair vanished by the time the mice were 7 to 10 days old. Scientists say their next step will be to figure out which genes regulate tissue regeneration in mammals—including possibly humans—and why they turn off so early in life. “Then we can look for drugs that activate the genes,” study co-author Hesham Sadek tells The New York Times. “Maybe we can remind the heart how to do this” in adults. If that’s possible, says Stephen Badylak, a professor at the University of Pittsburgh’s McGowan Institute for Regenerative Medicine, “the therapeutic potential is huge.”
How sea turtles navigateThe moment loggerhead sea turtles hatch, they embark on a complex ocean voyage that covers thousands of miles; those in Puerto Rico head northeast, while those in the Cape Verde Islands swim northwest. How do they know which way to go? After decades of research, scientists think they have the answer. Experts have established that migratory animals determine latitude by sensing how the magnetic pulls of the north and south poles alter as they move north or south. But those pulls don’t change as one moves east or west, making determining longitude “the most difficult part of open-sea navigation,” biologist Nathan Putman of the University of North Carolina tells BBC.com. In a new study, however, Putman and colleagues show that the turtles are innately able to sense slight variations in the angles at which the magnetic field intersects the Earth’s surface. This changing inclination of the field, coupled with the intensity of the north-south pull, gives the turtles “an X,Y coordinate system,” says Putman, that serves them like a GPS.