ScienceCache
Vol. 179
July 30, 2004
HIGHWAY DATA TIES SIDE-IMPACT CRASHES TO BRAIN INJURY
Occupants of automobiles involved in side-impact crashes are three times
more likely to suffer a traumatic brain injury than people involved in
head-on or other types of collisions, according to a study published
online for the August edition of Annals of Emergency Medicine. Lead author
Jeffrey Bazarian, an attending physician in Strong’s Emergency
Department who has been studying several aspects of brain trauma, also
found that brain injuries from side-impact crashes are usually more severe.
Bazarian and colleagues also found that seatbelt use, not frontal air
bags, was associated with a reduced risk of brain injury after a crash,
and that better head protection could reduce all crash-related brain
injuries by up to 61 percent, and fatal or critical brain injuries by
up to 23.5 percent. In raw numbers, that would translate into 2,230 fewer
deaths or critical injuries each year. Federal regulators have recently
begun discussing new rules for side air bags, which are not available
as standard equipment in most vehicles at this time; consumers must pay
about $400 extra to have them installed. “If the sides of cars
can be made as safe as the front, many fatal and non-fatal brain injuries
could be prevented. Increasing the number of vehicles with side air bags
that protect the head would be an important step in the right direction,” says
Bazarian. The data came from real accidents logged by the National Highway
Traffic Safety Administration, rather than from crash tests with dummies.
The difference is notable, Bazarian explains, because it’s difficult
to accurately simulate a brain injury in a dummy.
Full story
GLOBAL WARMING MODELS COME UNDER PHYSICIST’S SCRUTINY
Two studies published in the latest issue of Geophysical Research Letters
underline how uncertain and complex the understanding of global climate
can be. Both reports emphasize some of the shortcomings in current weather
models that scientists use to determine the effect of carbon dioxide
on the Earth’s average temperature. The first paper by physicist
David Douglass compares temperature data from several altitudes above
the Earth’s surface with what the top three internationally used
global weather models predict happens at these altitudes when carbon
dioxide is introduced. “The models are relatively accurate at predicting
the temperatures at the Earth’s surface, “says Douglass, “but
when you go a few miles up, they diverge dramatically. The models are
really challenged to explain these results.” Though the study doesn’t
suggest what might be causing the discrepancy, it clearly shows an area
of disagreement that today’s global models need to address in order
to increase their accuracy. Douglass’s second paper adds weight
to the veracity of satellite temperature readings over the last two decades,
helping to resolve a disparity over the measurement of Earth’s
temperature that has long dogged scientists. The new findings suggest
that Earth’s overall temperature is increasing, but less than the
increase noted by surface thermometers.
Full story
SCIENTISTS FINGER SURPRISE CULPRIT IN SPINAL CORD INJURY
ATP, the vital energy source that keeps our body’s cells alive,
runs amok at the site of a spinal cord injury, pouring into the area
around the wound and killing the cells that normally allow us to move,
scientists report in the cover story of the August issue of Nature Medicine.
Doctors have known that initial trauma to the spinal cord is exacerbated
by a cascade of molecular events over the first few hours that permanently
worsen the paralysis for patients. But the finding that high levels of
ATP produced by astrocytes kill healthy cells in nearby regions of the
spinal cord that were otherwise uninjured is surprising and marks one
of the first times that high levels of ATP have been identified as a
cause of injury in the body. When the research team blocked ATP’s
effects on neurons, rats with damaged spinal cords recovered most of
their function, walking and running and climbing nearly as well as healthy
rats. The research offers promise mainly to people who have just suffered
a spinal cord injury, not for patients whose injury is more than a day
old. “There is no good acute treatment now for patients who have
a spinal cord injury,” says lead researcher Maiken Nedergaard of
the Department of Neurosurgery. “We’re hoping that this work
will lead to therapy that could decrease the extent of the secondary
damage. This is an unusual way of looking at spinal cord injury. Much
of the focus of research has been on trying to re-grow portions of the
spinal cord. We’re trying to stop the damage up front.”
Full story
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