University of Rochester

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Research Roundup

Scientists find 'smoking gun' of extinction

Evidence is mounting that 251 million years ago, a meteor the size of Mount Everest smashed into what is now northern Australia, triggering mass volcanic eruptions and wiping out all but about 10 percent of the species on the planet in what's known as the "Great Dying." Researchers at Rochester and the University of California at Santa Barbara have published a paper in Science that claims to identify the crater made by that meteor.

Robert Poreda, professor of earth and environmental sciences, and Luann Becker, research scientist in geological sciences at UC Santa Barbara, examined core samples taken by an oil-drilling exploration team in 1970, in the area of Bedout, just off the northwestern coast of Australia. Now covered by two miles of sediment, this area was most likely dry land 251 million years ago.

"They were unlike any volcanic rocks I've ever seen," says Poreda. "The rocks were shock melted from an impact. Once we looked at Bedout with the understanding that it was likely a crater, the geophysics just fell into place. We left convinced Bedout was our crater."

The scientists built on their previous research: In 2001, Poreda and Becker announced that they had detected in 251- million-year-old strata all around the globe specific isotopes of helium and argon that could only have come from space in the form of a giant meteor, and last November, Poreda, Becker, and Asish Basu, professor of earth and environmental sciences, published another article in Science stating that they had found actual pieces of the meteorite that struck the Earth in the same global strata.

Personal factors affect cancer treatment expectations

Age, gender, and educational background influence what side effects patients expect from their cancer treatment, University researchers found.

Maarten Hofman of the Wilmot Cancer Center worked with a team of investigators to characterize the side effect expectations of 938 people with cancer prior to treatment and found that patients under 60 expected more side effects than others over 60, and women expected more symptoms than men. The study, published in the online edition of Cancer, also showed that college-educated patients anticipated more side effects than those who had only a high school education. And patients with hematologic cancers, such as leukemia, and lung cancer expected the greatest number of side effects, while those with prostate cancer expected the fewest.

Researchers develop 'custom' Alzheimer's vaccine

Using a harmless form of the herpes virus, Medical Center scientists have taken an important step toward creating a vaccine against Alzheimer's disease, customizing the response of the immune system with unprecedented precision. The work was published in the online edition of Neurobiology of Aging.

Howard Federoff, professor of neurology and director of the Center for Aging and Developmental Biology, and William Bowers, assistant professor of neurology, set out to create a vaccine without harmful side effects by boosting part of the immune system not responsible for the side effects. Though the current study was not in people but in mice, researchers are excited because it demonstrates a level of control over an Alzheimer's vaccine that was previously unattainable.

"This work provides a platform to shuffle the immune response, a flexibility to modify the approach to create a vaccine that is safe and efficacious," says Federoff. "This points the way toward shaping and modulating the exact immune response needed to fight or prevent Alzheimer's disease."

The team is conducting several more studies designed to contribute toward a custom vaccine against Alzheimer's.


Finding the hole in the defenses of cavity-creating microbes

Microbiologists at the Medical Center have discovered a chink in the armor that bacteria use to survive the hostile environment of the human mouth.

In a paper in the July 1 issue of the Journal of Bacteriology, Robert Quivey, associate professor in the Center for Oral Biology, and graduate student Elizabeth Fozo discuss a vulnerability of Streptococcus mutans, the dominant bacterium in mouths. Scientists have known for some time that the microbe specially modifies itself once it starts producing acid in the mouth. The Quivey group has shown that the changes include shuffling fatty acids in its membrane--much like a bricklayer might move bricks to fortify a fence--so it can withstand the wash of acids that it sends pouring into the mouth.

The Rochester team found that a gene known as fabM is responsible for changing the membrane's composition and enables S. mutans to become more resistant to acid. When Fozo and Quivey knocked out the gene in S. mutans, the bacteria's defenses fell; the cell membrane was no longer able to protect against the acid the bacteria churn out. By taking advantage of fabM, it may be possible to kill the bacteria and reduce cavities.

Depression differs for elderly

Paul Duberstein, associate professor of psychiatry and oncology, has identified risk factors associated with depression and suicide in the elderly and observed some surprising differences in the way depression manifests itself in older adults compared to children and younger adults.

"Kids with depression will express feelings of sadness more readily, but older adults may not show or express sadness as much," explains Duberstein, codirector of the Center for the Study and Prevention of Suicide. More common signs of depression among the elderly include a lack of appetite, fatigue, and problems concentrating--the kinds of symptoms often attributed to the aging process.

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