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Expert on Effects of Toxic Chemicals on Brain to Be Honored

Thursday, October 09, 2008

A scientist who helped create a discipline crucial to our ability to measure the effects of toxic chemicals on our health will be honored by scientists around the world next week.

Colleagues will gather and hold a “festschrift” to celebrate the career of Bernard Weiss, Ph.D., professor of Environmental Medicine at the University of Rochester Medical Center, which is home one of the world’s original programs focusing on how these chemicals threaten our health.

The celebration is an ancient German custom highlighting a professor’s career and will include presentations and new findings made possible by Weiss’ own research. He will be honored during a pair of conferences that are attracting more than 200 scientists to Rochester next week.

The 25th International Neurotoxicology Conference begins Sunday and runs Oct. 12-16. The conference, founded by Joan Cranmer, Ph.D., of the University of Arkansas for Medical Sciences, is taking place in Rochester this year partly to recognize Weiss. The conference will focus on the environmental factors that influence neurological and behavioral disorders, such as recent findings that pesticides may play a role in the development of some cases of Parkinson’s disease.

Weiss will be honored Wednesday, Oct. 15, during a related meeting, the 21st Rochester Conference on Environmental Toxicity, a series of conferences he helped establish 40 years ago.

Weiss is one of the founders of a field known as behavioral toxicology, which describes efforts by scientists to track the effects of toxic chemicals by creating ways to measure their impact on behavior. For instance, it’s through antisocial behaviors and performance on psychological tests that doctors and scientists can track the effects of lead exposure on young children. Scientists like Weiss have studied such effects in both humans and in animal models and have helped create tools to measure their impact.

“Bernie is the most creative and visionary scientist in our field,” said Cranmer, professor of Pediatrics and Toxicology at the University of Arkansas for Medical Sciences. “He does not recognize traditional disciplinary boundaries and always thinks outside the box. Bernie’s energy knows no bounds – he is a scientist, poet, gambler, and an adventurer. For the second issue of the international journal Neurotoxicology I asked Bernie to write an autobiographical statement. Thirty years ago, he wrote:

“We are all gamblers. We scheme to conquer chance, to beguile it into surrender, to lull it into forgiveness. In the end, it subdues us; but without malice, and at times to our advantage. Like other lives, mine has been hostage to random collisions….[this science] is buoyed by new visions, a ferment of disciplines, and energetic young scientists. . . . Neurotoxicology will continue to be an adventure as long as its practitioners remain adventurers.”

“Bernie is still gambling and hunting, as anyone who has attended these conferences will attest,” Cranmer added.

After earning his doctoral degree in psychology at the University in 1953, Weiss began his own research career at the Air Force School of Aviation Medicine in Texas, where he first began research on how chemical agents such as drugs and nutrients influence behavior. He then moved to Johns Hopkins, in an era when the first tranquilizers were coming into use. Medications like Miltown and Thorazine exerted powerful effects on the brain, and they attracted the interest of Weiss, who realized that scientists needed methods to measure their impact. It was during his nine years at Johns Hopkins that be began developing ways to measure the impact not only of such medications but of many other chemicals, such as analgesics and stimulants, that affect the brain.

In the mid-1960s, the University was establishing a program in toxicology and turned to Weiss, who was lured to Rochester after building one of the first mini-computers ever used in biomedical research. He joined the University faculty in 1965, becoming part of the foundation of a department that was the first in the world to grant a doctoral degree in toxicology.

“This was about the time that Rachel Carson’s book Silent Spring came out, and there was a real awakening. Scientists were already realizing they needed to undertake more research in toxicology, and the threat of chemical exposure to our health was taking root among the general public as well,” Weiss said.

During his career, Weiss has studied the effects on the brain of dozens of chemicals. For years, scientists thought that the human brain went through life relatively unchanged, but scientists now recognize that the brain is constantly changing and adapting in response to the environment, making work such as his more critical than ever.

Weiss is currently studying chemicals known as phthalates that are widely used in plastics. Phthalates fall into a class of chemicals known as endocrine disruptors that can disturb the action of hormones like estrogen and testosterone, causing a broad array of effects, including changes in the brain.

He’s currently looking at whether chemicals that disrupt testosterone have “feminized” the male brain in rats, which generally respond biologically to such chemicals in the same way that people do. The compounds are found nearly everywhere – food containers, plastics, shampoos, skin moisturizers, detergents, sunscreens, pesticides, and a number of other products.

“These chemical exposures have been going on for years, but at least now, we are finally in a position to really be aware of them and to begin taking steps to reverse what is happening. The trouble is that it will take a long time to change our exposure patterns. The change won’t happen overnight,” said Weiss.

Weiss is also interested in measuring the effects of toxic chemicals over a lifetime, instead of focusing on a one-time exposure as many studies do. He points to new findings by his colleagues that lead can weaken bones decades after a child is exposed to the substance. Another topic attracting his interest is “chemobrain,” which describes the cognitive difficulties that many patients with cancer experience after undergoing chemotherapy.

Weiss has received several honors. He was named Scientist of the Year by the Association of Children and Adults with Learning Disabilities in 1986, and in 2003 he received a Distinguished Investigator Award from the Neurotoxicology Specialty Section of the Society of Toxicology. During the mid-1970s, Weiss took part in the U.S.-U.S.S.R. Environmental Health Exchange Agreement, where he led several U.S. delegations in discussions of behavioral toxicology with their counterparts across the globe.

In just the last five years, Weiss has been part of advisory boards reviewing data and making recommendations about dioxin, metals, dental amalgams, the environmental conditions on NASA spacecraft, and the air quality aboard commercial airplanes.

To honor Weiss, his colleagues and former students are creating the Bernard Weiss Endowment Fund, which will be used to strengthen toxicology graduate training and research programs by enhancing recruitment of talented future leaders of the field, particularly those with an interest in neurotoxicology. Anyone interested in more information should contact Carmen Aiezza at (585) 275-0808, Further information is available at

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