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Weight loss may
cut cancer risk
By Nathan Seppa
Losing weight can knock down levels of
inflammatory cells and proteins in the
body. Since chronic inflammation is a risk
factor for many cancers, the finding suggests weight loss might reduce cancer risk.
The inflammation reduction came
only with weight loss from dieting. Peo-
ple who embarked on an exercise-only
program failed to lower their inflamma-
tory load substantially, despite losing
several pounds in many cases. The report
appears in the May 1 Cancer Research.
Enzyme shot may top acupuncture
Mouse study finds injection provides days of pain relief
By Tina Hesman Saey
A new treatment mimics the pain-block-ing mechanism of acupuncture and offers
longer-lasting relief, at least in mice.
Injecting an enzyme called PAP into
an acupuncture point behind the knees
of mice relieved pain caused by inflammation for up to six days, Julie Hurt and
Mark Zylka of the University of North
Carolina at Chapel Hill report online
April 23 in Molecular Pain. That’s almost
100 times as long as pain relief from acupuncture, which typically lasts about
1 ½ hours.
“The beauty of Mark’s study is that it
takes advantage of the molecular mechanism of acupuncture and improves upon
it,” says Maiken Nedergaard, a neuroscientist at the University of Rochester in
New York. She and colleagues have demonstrated that inserting and manipulating acupuncture needles causes the body
to release a chemical called adenosine.
Adenosine acts as a local anesthetic to
slow pain messages to the brain, she says.
An enzyme called PAP, shown here in
pink on the membranes of pain-sensing
neurons, suppressed inflammatory and
nerve pain in mice for up to six days.
Zylka had already been studying PAP,
which stands for prostatic acid phosphatase, when Nedergaard’s research
on the release of adenosine during acupuncture was published. The study gave
him the idea that boosting adenosine at
acupuncture points, which are located
where nerves contact muscle, could be
a localized way to treat pain.
Adenosine lasts only minutes in the
human body, so injections of the chemical
itself were not an option. But PAP, which
produces adenosine by breaking down
adenosine monophosphate, or AMP, lasts
a long time and can continue churning
out adenosine as long as it has a supply
of AMP. Muscles are a ready source of
AMP, itself a breakdown product of the
molecule ATP, which cells use for energy.
PAP injections in mice with inflamed
paws made the limbs less sensitive to
heat and poking but didn’t cause muscle weakness or other discernible side
effects, the researchers found.
Other scientists have postulated that
acupuncture releases feel-good chemicals called endorphins, which work all
over the body. But the new study helps
cement the idea that acupuncture really
works locally, Nedergaard says.
Not only does PAP relieve inflammatory pain longer than acupuncture does,
it also relieves nerve pain in mice, testing
showed. Clinical studies in people have
found that some patients with nerve pain
get worse after acupuncture, says physi-cian-scientist Jon Levine of the University of California, San Francisco.
ZYLKA LAB/UNC-CHAPEL HILL