SCIENCE OBSERVER
In the News
This roundup summarizes some notable recent items about
scientific research, selected from news reports compiled in
Sigma Xi's free electronic newsletters Science in the News
Daily and Science in the News Weekly. Online: sitn.sigmaxi.org and www.americanscientist.org/sitnweekly
Deciphering a Lost Technology
For more than a century, scholars have puzzled over the remains of a
strange object recovered from a Roman shipwreck off Greece, a geared
device dubbed the Antikythera Mechanism, which is believed to date
from the late second century B.C. Using high-resolution x-ray
tomography to probe the surviving pieces, a team of astronomers,
archaeologists and technologists have shed more light on the nature
of this intriguing artifact, which at one time was able to predict
lunar and solar eclipses and may have also been used to display the
positions of planets. The Antikythera Mechanism is considerably more
complex than anything known to have been built in the millennium
that followed its construction.
Freeth, T., et al. Decoding the ancient Greek
astronomical calculator known as the Antikythera Mechanism.
Nature 444:587-591 (November 30, 2006)
Muscular Dystrophy Reversed
Duchenne muscular dystrophy, a genetic disease that
causes progressive paralysis, often results in death before age 30.
Currently, there is no effective treatment. But investigators have
recently demonstrated what may be a promising approach using dogs
suffering from an analogous disease: golden retriever muscular
dystrophy. Afflicted retrievers were infused with a type of
vessel-associated stem cell called mesoangioblasts. The animals
treated with such cells taken from normal dogs showed marked
improvements in muscle-contraction force and, in many instances, the
preservation of their ability to walk. Thus it is reasonable to hope
that similar mesoangioblasts may one day provide a stem-cell therapy
in people suffering Duchenne muscular dystrophy.
Sampaolesi, M., et al. Mesoangioblast stem cells
ameliorate muscle function in dystrophic dogs. Nature
444:574-579 (November 30, 2006)
Then There Was Light
On January 18, 2000, an exceptionally bright meteor lit up the dawn
sky over Canada's Yukon and Northwest Territories along with parts
of British Columbia and Alaska. Fragments of the 200,000-kilogram
mass that created this fireball landed on the frozen surface of the
Yukon's Tagish Lake, where they were later collected. The subzero
temperatures, along with careful collection techniques, allowed the
recovery of volatile compounds from this meteorite—a very
primitive type known as a carbonaceous chondrite. An isotopic
analysis of organic globules contained in some of these otherworldly
samples reveals that they formed at very low temperatures, probably
within the cold molecular cloud that later gave rise to the solar system.
Nakamura-Messenger, K., et al. Organic globules in the
Tagish Lake meteorite: Remnants of the protosolar disk.
Science 314:1439-1442 (December 1, 2006)
Put Down That Sunscreen
Scientists have long known that the incidence of multiple sclerosis,
an autoimmune disease, is higher in northern portions of the United
States than in the South. Now clues are emerging as to why this
regional variation exists. A key risk factor may be low levels of
vitamin D, which is produced naturally when skin is exposed to
sunlight. One of the properties of vitamin D is to suppress immune
response, so it makes sense that people deficient in this substance
may be more prone to suffer from an autoimmune disease.
Investigators confirmed this association using Army and Navy records
of physical disability to identify patients with multiple sclerosis
and then examined blood samples taken earlier and stored in the
Department of Defense Serum Repository.
Munger, K. L., et al. Serum 25-hydroxyvitamin D levels
and risk of multiple sclerosis. Journal of the American
Medical Association 296:2832-2838 (December 20, 2006)
Medieval Murder Mystery
The circumstances surrounding the sudden and simultaneous deaths of
Francesco I de' Medici and his wife Bianca Cappello in 1587 have
long suggested foul play—in particular the possibility that
they were poisoned by Francesco's brother, Cardinal Ferdinando, who
may have hoped that their deaths would allow him to become the next
Grand Duke of Tuscany. A new analysis of the couple's remains shows
high arsenic concentrations in soft tissue samples but low values in
Francesco's femur and beard hair, ruling out the possibility of
chronic arsenic exposure and indicating that they probably suffered
acute arsenic poisoning. Cardinal Ferdinando was not available for comment.
Mari, F., et al.The mysterious death of Francesco I de'
Medici and Bianca Cappello: an arsenic murder? British
Medical Journal 333:1299-1301 (December 23-30, 2006)
Another Cause of Alzheimer's
In 1993, investigators fingered the ApoE4 gene as a cause
of late-onset Alzheimer's disease. Yet that gene could account for
only about half of the cases of this devastating brain disorder,
which afflicts many elderly people. Now another culprit has been
identified: a variant of the SORL1 receptor. The team that made the
discovery included members from Columbia University Medical Center,
which is located in the Washington Heights neighborhood of upper
Manhattan. The Columbia University investigators noticed that
Dominicans living in Washington Heights suffered from Alzheimer's at
a rate about three times that found for the general population. That
clue prompted the collection of medical histories and blood samples
from Dominican families, allowing identification of the problematic
variant, which has since been found to exist in several other populations.
Rogaeva, E., et al.The neuronal sortilin-related
receptor SORL1 is genetically associated with Alzheimer
disease. Nature Genetics (January 14 advance online
edition)
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