Health & Science

A revolutionary shortcut to stem cells

Scientists have developed a new and remarkably simple method of creating stem cells—one that could open a much smoother pathway to growing new organs for transplant. The new technique, based on triggering the natural ability of cells to regenerate after injury or stress, was discovered when researchers took normal blood cells from mice and soaked them in a mildly acidic bath for 30 minutes. That stress caused the cells to revert into pluripotent stem cells, which when injected into host mice were able to transform into normal cells of the heart, brain, and other organs. “It was really surprising to see that such a remarkable transformation could be triggered simply by stimuli from outside of the cell,” biochemist Haruko Obokata of the Japanese research institute RIKEN tells the Los Angeles Times. Previous methods of creating stem cells have depended on DNA manipulation or on the harvesting of embryonic cells, which is controversial because it involves the death of the embryo. Testing has already begun on whether the method works with human cells. “This could be the game changer that ultimately makes a wide range of cell therapies available using the patient’s own cells as starting material,” said University College London biochemical engineer Chris Mason. “The age of personalized medicine would have finally arrived.”

Hawking’s black hole theory

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Renowned physicist Stephen Hawking has declared that black holes don’t exist—at least not in the way we normally think about them, reports Nature.com. In a new paper, he tackles a scientific paradox regarding a black hole’s event horizon, or the threshold past which nothing can escape its gravitational pull. Under Einstein’s theory of relativity, a hypothetical astronaut floating across an event horizon would be blissfully unaware unless he tried to turn around and float the other way. But the laws of quantum mechanics suggest that the event horizon would be a seething band of energy, or firewall, that would incinerate the astronaut. Now Hawking proposes that black holes don’t have a sharply delineated event horizon, but rather an “apparent horizon”—a less fiery region where matter and energy are turned into a confusing mess that can eventually re-emerge as radiation. That would mean, Hawking writes, that “there are no black holes, in the sense of regimes from which light can’t escape.” In his new conception, radiation emerging from a black hole would possess—in radically different form—all the original information from whatever fell into it, thus preserving a key principle of quantum physics: that information can never be removed from the universe.

Is cognitive decline a myth?

Many older people can be slower to recall facts or learn new information because their brains are so stuffed with accumulated knowledge—not because of inevitable cognitive decline. That’s the conclusion of a new study by German researchers challenging the idea that otherwise healthy adults are bound to experience deteriorating brain function. “The brains of older people do not get weak,” Michael Ramscar of Tübingen University tells The Independent (U.K.). “On the contrary, they simply know more.” Using computer models, researchers simulated memory recall from different stages in a lifetime. The models with less information in their memory banks retrieved requested data more quickly, mirroring young adults, while the models packed with information were slower, in line with the performance of older ones. Researchers also analyzed the results of a prior linguistics test in which young volunteers outperformed their older counterparts at remembering pairs of unrelated words such as “necktie” and “cracker.” The German team concluded that the result, originally attributed to cognitive decline, really reflected older adults’ having a better understanding of language—and thus being naturally resistant to nonsensical pairings.

Different eras, similar plagues

The notorious Black Death that ravaged Europe from 1347 to 1351 and the plague that killed millions 800 years earlier were caused by different strains of the same bacterium, Yersinia pestis. Scientists discovered the link after sequencing bacterial DNA extracted from the teeth of two people buried in a 6th-century mass grave in Germany as victims of the so-called Plague of Justinian, named for the Byzantine emperor. The pandemic killed as many as 100 million people in Europe, northern Africa, and Asia, pushing the Roman Empire into a spiral of decline. Scientists say the fact that two strains of the bacterium were able to jump to humans from rats and fleas—its usual hosts—underscores its virulence. “That shows the jump is not that difficult to make and wasn’t a wild fluke,” bioarchaeologist Tom Gilbert of the Natural History Museum of Denmark tells USA Today. Changes in human hygiene and the advent of antibiotics make it unlikely that Yersinia pestis could spark another pandemic, though several thousand cases of plague still occur each year worldwide.