Health & Science

last updated 8 January 2015

The first human test of stem cells

Can stem cells heal damaged spinal cords and enable paralyzed people to walk again? In the first clinical test of its kind, says USA Today, surgeons have injected embryonic stem cells into the spinal cord of a paralyzed patient in the hope that it will regenerate broken neural connections. Stem cells are master cells that can give rise to more than 200 types of human tissue and so offer tremendous potential in treating disease and tissue damage. Embryonic stem cells are harvested from embryos created as a result of fertility treatments; their use has been embroiled in ethical debate. In the new trial, privately funded by the Geron Corporation, surgeons at the Shepherd Center in Atlanta are treating a recently paralyzed patient’s damaged spinal cord with millions of stem cells, to see if the cells travel to the site of the injury and grow into spinal sheath cells capable of transmitting neural signals. Similar treatments in rats have shown partial success. Researchers expect no miracles; this first trial is primarily aimed at testing the treatment’s safety. But after years of controversy, the human trial “is a major morale boost for scientists, clinicians, and most of all patients,’’ says regenerative-medicine expert Chris Mason. The test, he says, “marks the dawn of the ‘stem-cell age.’’’

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In the past four years, as many as 40 percent of the nation’s honeybee colonies have suddenly and mysteriously died off, to the alarm of both bee keepers and farmers who rely on bees to pollinate their crops. At last, biologists think they have a bead on the cause: “an unholy combination” of a fungus, Nosema ceranae, and a virus called invertebrate iridescent virus, says Popular Science. The fungus was previously suspected, but its interaction with the virus—which is present in 75 percent of healthy colonies—is nearly 100 percent fatal. Scientists, using protein-analysis software developed for the military, reached that conclusion after a painstaking study that involved, among other things, grinding dead bees into a paste with a coffee grinder. How exactly the two invaders, which inhabit the bee gut, do their damage is unclear; they may disrupt navigation, causing bees to fly off in all directions from the hive, or may prompt some sort of insect insanity. “They’re co-factors, that’s all we can say at the moment,” says study author Jerry Bromenshenk of the University of Montana.

Pessimism isn’t just for people; some dogs, too, may have a gloomy view of life, says the London Daily Telegraph. In a new study, British researchers monitored the activity of 24 shelter dogs kept apart from people and other dogs. From time to time a food bowl—sometimes empty, sometimes full—was placed in a random location in the room. Dogs that raced to check it out displayed a host of traits that researchers labeled optimistic, while those that ambled over, or just lay down and ignored it, were deemed pessimistic. The researchers found that pessimistic dogs were far more likely to bark, scratch at the door, or jump on furniture when left alone. This suggests that separation behavior, like chewing on slippers, reflects the dog’s pessimistic belief that the owner is not coming back. Dogs that have been actually abandoned or mistreated, researchers said, are more likely to suffer from pessimism and “separation anxiety.’’

There’s no getting around it: Hours of TV and computer time leads to psychological and academic problems for young people, even if those same kids are physically active for large chunks of the day, says New Scientist. In a study involving 1,013 kids ages 10 and 11, researchers in England found that kids who watched TV or were online for two or more hours a day were 61 percent more likely to have emotional, social, and concentration problems, as measured by a standard psychological test for children. Spending time outdoors only had a modest effect on the psychological impact. So it’s not the sedentary nature of TV watching and computer use that’s primarily to blame; it’s something about the content or experience itself. Parents who limit TV and computer time to less than two hours a day need not worry, says study author Angie Page: “It’s only above the two-hour threshold that you start to see the negative psychological effect.”

People who sweat more, vote more, says New Scientist. Using skin sensors, researchers at the University of Nebraska measured the sweat responses of 51 people as they viewed images known to make people perspire, including pictures of sunsets, vomit, cute animals, and fistfights. Those who perspired more turned out to be far more likely to participate in politics by voting or contacting a government official; in fact, the people who sweated the most were about twice as likely as the least sweaty to be politically engaged. Why strong physical reactions are connected to voting is not certain, says study author Michael Gruszczynski, but the findings suggest that people who get easily worked up are more likely to engage in political activity.