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Snakes, lasers could buy time for stroke victims!
Venom from Malayan Pit Vipers and "healing light" lasers are being used on stroke patients in North Jersey in studies to develop safe new treatments for the nation's third-biggest killer.
Scientists hope the venom and lasers can lengthen the window of time -- now just three hours -- to treat people who have suffered an acute stroke. Currently, fewer than 5 percent of stroke patients get to treatment in time.
Eleven people die each day in New Jersey from stroke -- deaths that include more women than men and a disproportionate number of African-Americans. Strokes lead to more than 26,000 hospitalizations in the State each year. A stroke occurs every 45 seconds in the United States. But treatment options are few.
"Only one drug has been approved for acute stroke, and that's tPA [tissue plasminogen activator]," says Dr. Kenneth A. Levin, medical director of The Valley Hospital's Stroke Center in Ridgewood.
Conditions have to be just right for this clot buster to be used. It must be injected within three hours of the onset of symptoms -- and only after a physician has confirmed the stroke is caused by a clot rather than bleeding in the brain.
That crucial three-hour window passes by most patients. Some wake up in the morning with symptoms and don't know when the stroke occurred. There may be delays in getting to a hospital or confirming a diagnosis through CT imaging. As a result, tPA is used in only 3 percent to 5 percent of stroke patients.
A drug developed from the venom of pit vipers may help patients up to six hours after a stroke. Snake venom has already been shown to break up clots. Valley Hospital is part of a study to find out whether it helps patients hours after symptoms appear.
The Malayan vipers are raised at a vivarium in Germany, recently opened by Neurobiological Technologies, the California manufacturer of the drug, Ancrod. The company has a satellite office in Edgewater.
The extended time of treatment "would allow a lot more patients to benefit," Levin said. Like other clot busters, it carries a very small risk of causing brain hemorrhages.
Valley was one of 50 hospitals around the country that participated in an initial study of Ancrod that measured the effects of administering the drug within three hours. Levin was co-author of a report in the Journal of the American Medical Association in 2000 that found Ancrod was better than a placebo when stroke patients were assessed three months later.
Laser beams that bombard the soft tissue of the brain with infrared light are also showing promise. Unlike surgical lasers, these do not destroy the tissue. Rather, the infrared energy is absorbed by an organelle within each brain cell that serves as the cell's power plant, leading it to increase production of ATP -- adenosine triphosphate -- the cell's energy-storing compound. The increase in ATP increases the potential energy of the cell, a protection against cell death.
The lasers are directed into the brain through 20 ports on a skull cap worn by the patient, whose head has been shaved for the treatment. "It's very safe," Levin said. "There's almost no downside." The study's goal is to measure the effectiveness of the treatment if administered within 24 hours of the onset of stroke symptoms.
Valley Hospital is also participating in a study to test a drug -- known only as "MK0724" -- that would extend the time available for treatment to as long as 24 hours. Developed by Merck, it's not a clot buster, but a drug that protects brain cells surrounding the clot from dying.
Scientists call that region the "stroke penumbra," likening it to the halo of light around the dark center of a solar eclipse. They want to minimize the size of that area of brain damage. This medication does so by blocking the release of a cell-destroying protein.
New York-Presbyterian Hospital in Manhattan is also working with stroke patients, testing a corkscrew-like device that physically removes a stroke-causing blood clot in the brain. This "Merci retriever" is threaded through a catheter inserted through the femoral artery in the groin, and guided using X-ray imaging to the clot in the brain.
The device is already in use for removing clots at many hospitals. This clinical trial at New York-Presbyterian evaluates its use specifically as a treatment for stroke up to eight hours after symptoms appear.
Every minute counts in the treatment of stroke. Symptoms include: sudden numbness or weakness of the face, arm, or leg, especially on one side of the body; sudden confusion, trouble talking, or understanding speech; sudden trouble seeing in one or both eyes; sudden trouble walking, or loss of balance or coordination, or sudden severe headache with no known cause.
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by Lindsy Washburn, Staff Writer of http://www.northjersey.com/
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