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Research Briefs

Watch and learn
If you want something done right, goes the conventional wisdom, do it yourself. But according to Dartmouth research led by Emily Cross, Ph.D., if you just want to learn how to do something right, you can sit back and watch someone else do it. "The ability to improve by observation alone, without concurrent practice," she wrote in Cerebral Cortex, "is a powerful capacity of humans." Cross measured the brain activity of participants as they tried to learn dance sequences and found that studying the sequences passively activated the same neural regions as did actively practicing them.

Got calcium?
"Several national organizations recommend a high calcium intake to achieve optimum bone health," wrote members of the DMS Departments of Medicine and of Community and Family Medicine in a recent article. But some research has called that recommendation into question. To help settle the dispute, the DMS team conducted a long-term study on the effects of calcium supplementation. In a recent issue of the American Journal of Clinical Nutrition, the researchers wrote that taking a daily supplement reduced the risk of bone fracture by 72%—but that the benefits disappeared once participants stopped taking the supplements.

A look at iron and age
In the world of superheroes, being Iron Man chalks up as a huge plus. But for mere mortals (female as well as male), having too much iron can be problematic. That's because as people age, they accumulate iron in their blood—and elevated iron levels have been linked to cancer. DMS's Leo Zacharski, M.D., reported in the Journal of the National Cancer Institute just how strong that link is. The findings are preliminary, he cautions, but "analysis showed a 37% reduction in overall cancer incidence with iron reduction" from periodic blood-letting.

Calculating clot risk
To investigate safety concerns about drugeluting stents—tiny mesh tubes that prop open blood vessels—DMS researchers compared outcomes in about 67,000 Medicare patients, roughly half in the era before drugeluting stents (DESs) and half afterward. Although other studies have suggested "some incremental risk" of a dangerous blood clot with DESs, "we can detect no adverse consequences to the health of the population," wrote DHMC cardiologist David Malenka, M.D., and his coauthors in the Journal of the American Medical Association. "Whatever the increased risk, . . . it is more than offset by a decrease in risk" of a renarrowing of the blood vessel.

A BP of 120 over ecstatic
It's hard to quantify happiness. Studies have shown that some nationalities, such as the Dutch, consistently report higher levels of contentment than, say, Germans, but cultural differences call those results into question. Dartmouth economist David Blanchflower, Ph.D., took a medical approach, arguing in the Journal of Health Economics for blood pressure (BP) as an indicator of well-being. He found in a survey of 15,000 people in 16 European nations that "happy countries seem to have fewer blood pressure problems." So if you're happy and you know it, your BP will surely show it.

Problematic polymorphisms
Scientists know smallpox vaccination can have side effects, but they don't know why. To find out, researchers at DMS and several other institutions examined polymorphisms—slight genetic differences—at 1,442 locations on the human genome during a vaccination trial. They identified 36 sites that seemed to be linked to adverse reactions; in a second trial, three of those polymorphisms again correlated with side effects. "The fact that the results of our first study were independently replicated in the second study," wrote the teamin the Journal of Infectious Diseases, "strengthens the plausibility of these genetic associations.

The Milken Institute ranked New Hampshire ninth among the 50 states on its Science and Technology Index, for having assets that are likely to foster high-quality economic growth.

Short-term mortality is the same for drug- resistant as for non-resistant staph infections. But, found a DMS study, mortality a year later is higher in resistant staph—51% vs. 32%.

DMS infectious disease expert Peter Wright, M.D., was invited by the New England Journal of Medicine to assess a new way of growing avian flu vaccines; he hailed it as promising.

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