快猫短视频

HIV infection may trigger a muscle disease similar to the one that struck
down baseball star Lou Gehrig and afflicts British physicist Stephen Hawking.
The discovery adds weight to the theory that unknown viruses are to
blame for both diseases, and raises hopes that vaccines or antiviral drugs could
reverse its devastating effects.

Lou Gehrig鈥檚 disease, or amyotrophic lateral sclerosis (ALS), gradually
destroys the nerves that control muscles. The symptoms begin with muscle pain or
stiffness, slurred speech and difficulty swallowing, but progress rapidly. Most
patients die within five years, when the nerves that support breathing are
knocked out.

Antoine Moulignier of the Adolphe de Rothschild Foundation in Paris and his
colleagues have examined 1700 HIV-positive patients with neurological problems
over a 13-year period. Six of them had symptoms virtually identical to
ALS鈥攆ar more than would be expected in such a small group.

When the six patients were given antiviral therapy, the ALS symptoms stopped
progressing in one patient, improved in three and disappeared completely in two.
A team of researchers in New York have also reported that an HIV-positive
patient with ALS symptoms completely recovered after anti-viral therapy.

鈥淭his really pushes the viral theory forward,鈥� says Burk Jubelt, a
neurovirologist who specialises in muscle diseases at the State University of
New York鈥檚 Upstate Medical University in Syracuse. 鈥淭his shows a virus can cause
this disease. It suggests we should look harder for other viruses.鈥�

Jubelt says that another virus may be taking advantage of the havoc HIV
wreaks on the immune system. But Moulignier points out that there are many other
ways that HIV could contribute to ALS symptoms: by infecting nerve cells,
releasing toxic substances or inducing an autoimmune disease.

To date, no one has come up with a convincing explanation for ALS, though a
few cases have been linked to exposure to toxic metals, the side effects of
cancer or certain genetic factors. French researchers recently found the DNA
sequences of neuron-infecting echoviruses, which are close relatives of
polioviruses, in the spinal cords of ALS patients
(快猫短视频, 15 January 2000, p 6).
But this year, another study failed to find any trace of
echoviruses in people with ALS.

And Raymond Roos of the University of Chicago, Illinois, says many people
with ALS don鈥檛 show any signs of viral infection. But the HIV-triggered disease
could yield important insights into classic ALS, he says. 鈥淚t may share a common
mechanism of motor neurone death.鈥�