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Discoveries
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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