Body & Brain

Handling fruit can throw off blood-glucose tests, plus an autism gene and itchy feelings in this week’s news

Unreliable blood-glucose readings People with diabetes who monitor their blood glucose by pricking a finger can get an erroneous reading if they handle or peel fruit beforehand, two studies in the March Diabetes Care show. In one report, researchers in the Netherlands found that some people who didn’t wash their hands before taking a blood-glucose reading got widely different readings between the first and second drops measured. Handling fruit first led to such differences in nearly all patients. Scientists in Japan found that blood-glucose tests were elevated in people who had peeled fruit, despite swabbing the finger with alcohol after the peeling. — Nathan Seppa Antibiotics in the ICU Giving intensive-care-unit patients a preventive course of antibiotics for digestive-tract bacteria may lessen their risk of becoming infected by drug-resistant strains of the microbes, a Dutch team reports online March 21 in Lancet Infectious Diseases . The researchers randomly assigned more than 5,000 ICU patients to get either standard care (no antibiotics) or one of two courses of antibiotics, one for respiratory infections and the other for digestive tract ailments. While 18 patients getting standard care and 20 others getting antibiotics for respiratory ailments developed highly drug-resistant bacterial infections, only eight of those getting antibiotics for digestive microbes did. The study contradicts earlier research. — Nathan Seppa Older brains show less variety The activity of younger, sharper brains varies more than older, slower brains when doing the same jobs. Using functional MRI scans, Canadian researchers found that in a series of timed tests, young people’s brains showed a wider variety of blood-flow changes as they performed the same task over and over than did the brains of older people. Younger people also outperformed the older subjects. The results, reported March 23 in the Journal of Neuroscience , suggest that decreased variability may be involved in the brain’s decline with age. — Laura Sanders Same itch, different feeling Warmth and burning sensations get progressively weaker the farther they are from the brain, but itchy sensations get stronger. Italian researchers studying how sensations stack up at different sites in the body applied warming, burning and itchy substances to the face, shoulder, hand, thigh and foot in 12 healthy subjects. An itch on the foot felt stronger to subjects than the same itch on the face, but the opposite was true for warmth and heat. The study, which will appear in an upcoming Neuroscience Letters , supports the idea that very specific nerve fibers carry itch, warmth and burning sensations to the brain. — Laura Sanders Autism gene Mice with a mutation in an autism-related gene repetitively groom themselves and aren’t interested in other mice, behaviors that are similar to those of people with autism spectrum disorders. The mutant mice groomed themselves so much that they developed sores. And unlike normal mice these animals spent more time investigating an empty cage rather than a cage that held another mouse, Guoping Feng of MIT and colleagues report online March 20 in Nature . The mutated gene, Shank3, has a role in brain cell communication. The results may help scientists better understand the neurological basis for autism spectrum disorders. — Laura Sanders

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