UM studies aim to solve riddles of Pfiesteria First team effort to examine microbe

August 20, 1998|By Heather Dewar | Heather Dewar,SUN STAFF

An ambitious new series of University of Maryland studies is aimed at solving some of the many riddles posed by toxic Pfiesteria -- from the way it mysteriously "ambushes" fish to its effects on specific cells in the brain.

Scientists in North Carolina and elsewhere are also studying the toxic microbe, and some of the new work being undertaken at the University of Maryland's School of Medicine and Center of Marine Science Biotechnology will overlap with those studies.

But university officials said yesterday that the $6.3 million, five-year set of studies in Maryland, paid for by a federal grant from the National Institute of Environmental Health Studies, will be the first time a team of scientists has been formed for a comprehensive look at Pfiesteria and its health effects.

At least 12 researchers from the Maryland institutions, joined by an administrator from the Johns Hopkins University medical school, will try to sort out the "central unanswered questions about Pfiesteria and human health," said team member M. Robert Belas, of the marine center.

To protect themselves from the microbe's effects, the scientists will use new, high-security lab facilities designed to prevent the escape of toxic cells into the environment. All will undergo memory tests before the research starts and will be tested again as the work progresses, to ensure they are showing no ill effects, Belas said.

Based on studies done in Maryland after last year's Pfiesteria outbreaks on the Lower Eastern Shore, the federal Centers for Disease Control and Prevention consider the microbe to be the cause of "estuarine waters associated syndrome," a disorder that affects people's ability to learn and remember new information, said Dr. Lynn Grattan, a neurologist on the new research team.

"There's actually at this point more that we don't know about the toxic health effects of Pfiesteria than we do know," Grattan said.

Pfiesteria has sickened laboratory workers at North Carolina State University, which until now has been the only high-security facility in the country where scientists can test toxic forms of the organism. The new lab at the marine biotechnology center will allow Maryland researchers to perform similar work.

Belas said the lab's projects will include development of a "DNA fingerprint" test that can quickly pinpoint toxic Pfiesteria in water -- now a long, painstaking process -- and attempts to identify the chemical signal emitted by schools of fish, which seem to cause Pfiesteria to switch from a harmless form to a lethal one.

Marine center scientists working with zebra fish "have already identified certain components in blood" that might trigger a response in Pfiesteria, Belas added.

At the medical school, Grattan and others will run brain scans and other tests on as many as 20 people who have been exposed to waters where a toxic Pfiesteria outbreak is occurring anywhere on the East Coast. Similar scans conducted on eight Marylanders exposed to Pfiesteria last year showed abnormally high activity in the part of the brain that controls memory, Grattan said.

Scientists want to find out what that "hyperexcitability" means, what happens to people who are exposed to Pfiesteria more than once, and whether a connection exists between the skin sores some people developed and memory problems, she said.

Because Pfiesteria's effects seem to be confined to one part of the human brain, it's likely that the toxin affects only one kind of brain receptor, said researcher Amira Eldefrawi. Humans have hundreds of types of these highly specialized nervous system cells, she said. Eldefrawi plans to test Pfiesteria's toxins on the brain receptors of rats, to find out exactly which cells respond to it.

Because humans and rats have many of the same receptors, and scientists understand the kind of work that some receptors do, it might be possible for the researchers to quickly figure out how Pfiesteria affects the brain. Eldefrawi, an expert on animal poisons, said Pfiesteria's harmful chemicals will surely turn out to be unique, but an antidote to its human health effects might exist.

"Every toxin is different," she said, "but once we know how it works, we may find out we already have the therapy for it."

Pub Date: 8/20/98

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