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Biotech / Medical : Neurobiological Tech (NTII) -- Ignore unavailable to you. Want to Upgrade?

To: Dr. John M. de Castro who wrote (785)	2/26/2000 2:28:00 AM
From: Cheryl Galt	Read Replies (1) \| Respond to of 1494

A Reuters Medical News summary of the vaccine article is in Medscape today. medscape.com Oral Vaccine Prevents Epileptic Seizures, Stroke Damage in Rats An experimental oral genetic vaccine that targets a subunit of the N-methyl-D-aspartate (NMDA) receptor protects rats against epileptic seizures and stroke damage, according to a report in the February 25th issue of Science. The effects of a single dose of the oral vaccine, which lasted for at least 5 months and did not impair the behavior of the rats, depended on the timing of brain injury, researchers report. While the long-term effects of the vaccine remain unknown, the approach may prove useful as a prophylactic treatment to prevent brain damage, according to Dr. Matthew J. During from Jefferson Medical College in Philadelphia, Pennsylvania, and colleagues. In an interview with Reuters Health, Dr. During said that it has long been known that the brain affects the immune system, but now it is clear that it works in the other direction. "The immune system talks to the brain more often than we ever thought," he said. One month after administering the adenovirus-delivered vaccine to rats, the investigators injected kainic acid to induce seizures in immunized rats and controls. Within 10 minutes, 19 of the 25 controls proceeded to status epilepticus, compared with just 2 of the 9 vaccinated rats. The vaccine appeared to have some effect even on one of the rats that had a seizure, since researchers did not detect any damage to its hippocampus. The authors speculate that the vaccine may "not only produce resistance to seizures but also protect against excitotoxic injury." In another experiment, when researchers induced a stroke in vaccinated rats and controls, total infarct volume was reduced by about 70% in vaccinated rats, according to the report. Unlike some NMDA antagonists that cause significant side effects, the vaccine did not appear to have a negative effect on the behavior of the rats. Part of the reason for the lack of behavior side effects may be that high levels of the antibodies produced by the vaccine cross the blood-brain barrier only after neuronal insult, not under normal conditions, Dr. During said in the interview. "This 'on demand' or selective delivery of the neuroprotective agent, limited both spatially to the site of injury and to the precise timing of injury, is one of the most promising features of our approach," the authors write. "A stroke vaccine that generates autoantibodies whose access to the brain and neuroprotective activity is spatially and temporally regulated may hold promise as a prophylactic measure to protect the brain." Exactly how long the effects of the vaccine will last is uncertain, Dr. During told Reuters Health, but he and his group "believe that it could last for many, many months or even years." The long-term effects of the vaccine still need to be studied, he noted. The next step in the research will involve human patients, although it is too early to test the actual vaccine, Dr. During said. Instead, hospital patients who are at high risk of having a stroke within a few days or a week will be treated with the antibodies that the vaccine produces. This study should show whether the antibodies can prevent a stroke or at least reduce its damage in people, according to Dr. During. Without the vaccination, the antibodies will only remain a few weeks, so there should not be any safety problems, he said. Science 2000;287:1453-1460. --------------------------------------------------------------------------------