6. 3
per 100,000
Global annual
venomous snakebite incidence
0.8
per 100,000
Venomous snakebite incidence,
North America
20. 3
per 100,000
Venomous snakebite incidence,
central Africa
sugar-containing soft drink per day
tacked on 1 pound every four years. Butter, refined grains, desserts, processed
or red meats, fruit juice, fried food or
foods containing trans fats added less
than that.
Other foods seemed to lower weight.
Adding a daily serving of yogurt knocked
off nearly a pound over four years, while
adding a serving of nuts or fruit was associated with a loss of about half a pound
each. An extra serving of whole grains,
vegetables or diet soft drinks reduced
weight slightly.
Changes in intake of dairy products
other than butter and yogurt, whether
low-fat or not, appeared to have little
effect on weight.
Specifying which foods may lessen or
prevent weight gain is highly practical,
says Christopher Gardner, a nutrition
scientist at Stanford University who
wasn’t involved in this study. “When you
choose one of these foods, you choose
not to consume something else,” he says.
The strength of the study, he says, is that
it demonstrates that “these are achievable differences because real, live people
did them.”
eavesdropped on brain activity using
electrodes, which showed a distinctive
split in working memory performance.
Packing one side of the screen with
squares caused nerve cells to go haywire.
But adding squares to the sparsely populated side of the screen caused little chaos.
Salve buys time
after snakebite
Ointment slows venom’s
progress to vital organs
By Nadia Drake
Indiana Jones, intrepid cinematic
archaeologist, is famously afraid of
snakes. Perhaps he wouldn’t need to be
if he had an ointment recently tested by
scientists in Australia. Quickly applying
a nitric oxide–producing ointment near
the bite site slows the spread of some
venoms, including the notorious eastern
brown snake’s, the researchers report
online June 26 in Nature Medicine.
“This treatment might make all the
difference between dying on the road
and getting to the hospital in time,” says
physician and tropical medicine specialist David Warrell of the University
of Oxford, who was not involved with
Applying a nitric oxide–producing
ointment right after being bitten by
some poisonous snakes, including this
eastern brown snake, can slow the
transport of venom to the vital organs.
the study. Worldwide, snakebites cause
about 100,000 deaths and 400,000 limb
amputations each year.
Physiologist Dirk van Helden at
the University of Newcastle in Australia and his colleagues showed that,
in humans, applying a nitric oxide–
producing ointment within one minute
of a simulated snakebite slows the transit
of injected tracer molecules. Foot-to-groin tracer travel times increased from
an average of 13 minutes without the
ointment to an average of 54 minutes
with the ointment, when applied in a
5-centimeter-diameter circle just up the
limb from the bite site.
The group also tested the effects of the
cream on rats injected with venom from
the eastern brown snake (Pseudonaja
textilis), native to Australia. In rats
slathered with ointment, symptoms of
snakebite toxicity set in about 96 minutes after injection, compared with
about 65 minutes in untreated animals.
The nitric oxide source in the ointment is nitroglycerin, the same compound used to treat angina. When
applied to the body, the ointment
releases microscopic amounts of nitric
oxide gas, which sinks through the skin.
There, the gas inhibits pumping of the
lymphatic vessels — the primary roadways for molecules too big to squeeze
through blood vessel walls and hitch a
ride in the bloodstream.
But victims might be out of luck if bitten by a black mamba or cobra, since the
ointment isn’t effective against venom
containing smaller toxic proteins capable of directly entering the bloodstream.
Another potential snag is the need for
bite victims to be quick on the draw. The
scientists applied ointment within 20
seconds of a snakebite in rats and within
a minute in the human tracer tests.
Van Helden hypothesizes that a combination of ointment and pressure treatment might be the best way to slow the
spread of snake venom. But “if I had the
ointment in my backpack,” he says, “that
would be the first I’d put on.”
