ScienceCache

Vol. 153
Nov. 20, 2003

EARTH'S GREATEST EXTINCTION LIKELY CAUSED BY ANCIENT METEORITE OR COMET
Long before the dinosaurs ever lived, the planet experienced a mass extinction so severe it killed 90 percent of life on Earth, and researchers think they've identified the culprit. "An ancient meteorite body, one from the days when the solar system was still forming, struck the Earth 251 million years ago," says Asish Basu, professor of earth sciences, in tomorrow’s issue of Science. The research is the latest volley in a decades-long debate over what caused "The Great Dying," the greatest elimination of life in the planet's history. While scientists have been wrangling over whether a meteor caused this great extinction ever since a meteor was fingered with the blame for the later dinosaur extinction, the new findings add weight to the argument that a major meteorite did strike the Earth 251 million years ago, likely triggering climate change and unprecedented volcanic activity. That one-two punch so affected the composition of the atmosphere that it took thousands of years to recover -- leaving only a relative handful of plants and animals alive. Previously, Basu published a study in Science that showed a massive and ancient lava flow in Siberia dated precisely to that greatest of extinctions 251 million years ago. The lava did not shoot out of the Earth like a giant volcano, but oozed molten rock for thousands of years -- so much lava, in fact, that if spread evenly, it would bury the surface of the Earth under 10 feet of magma. Further testing by Basu and Robert Poreda, professor of earth and environmental sciences and co-author of the current Science research, showed that the lava came from as deep as 1,800 miles beneath the surface. "These were not just examples of local magma bubbling through the crust," explains Poreda. "Something brought this lava all the way up from near the Earth's core."
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LOVED ONES OF SUICIDES GATHER FOR FIRST-EVER PANEL DISCUSSION
One woman’s husband committed suicide in their home after 30 years of marriage. Another woman’s 26-year-old son hung himself in his apartment. They’re the survivors – loved ones of suicides – who will share their stories in a first-ever local panel discussion to coincide with the fifth annual National Survivors of Suicide Day, Saturday, Nov. 22. “It’s an opportunity for survivors to connect with and hear the stories of other survivors in our community,” says Julie Cerel, a child clinical psychologist who will join the survivors on the panel. As a clinician and researcher, Cerel will discuss some common reactions following the suicide of a loved one and warning signs that a survivor needs help. “The panel will include survivors of different types of suicide – a teen, an adult child, and an older man – with the hope of showing the resilience of various types of survivors despite this traumatic life event,” says Cerel, whose research focuses on the implications of parental suicidal behavior on children. As part of the discussion, the medical center also will air a national satellite videoconference led by the American Foundation for Suicide Prevention. The national videoconference will link local survivor conferences around the country, helping survivors connect with others and express and understand the powerful and troubling emotions they’re experiencing. Following the national portion of the program, small group workshops will meet to give attendees the opportunity to share their personal stories with others who have experienced a similar loss.
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UNIVERSITY LEADING TEST OF EPILEPSY DRUG AGAINST ALZHEIMER’S
A medication that has been around for 20 years and successfully used to treat epilepsy, migraines and bipolar disorder may provide new hope for the more than 4 million Americans suffering with Alzheimer’s disease. The medical center is launching a national study involving 30 institutions to determine if the medication valproate preserves functioning and delays the expected decline associated Alzheimer’s disease. The $10 million study will target 300 patients with mild to moderate Alzheimer’s who are living at home and have not yet shown signs of agitation. Scientists will study whether patients who take valproate experience less agitation, as well as whether valproate will slow down the deterioration of memory and daily functioning that occurs as the disease progresses. “When we began to look at valproate in the laboratory, we were amazed to see that this simple drug blocked several key molecular events that we know are involved in the progression of Alzheimer’s,” says Pierre Tariot, professor of psychiatry and creator of the study. The study is the first to test an agent that may have the potential to block “tangles,” one of the hallmarks of Alzheimer’s disease linked with memory loss and other symptoms of dementia. Tangles are abnormal brain tissue structures formed by abnormal processing of a protein called tau. Normally, tau is crucial for intracellular functioning and structure, but in Alzheimer’s patients, a stringy cluster of tau and phosphate molecules form, leading to dysfunction that impairs the cell’s ability to communicate with neighboring cells. This eventually leads to cell death, contributing to the confusion, disorientation and forgetfulness associated with Alzheimer’s.
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ROCHESTER CHOSEN TO FOCUS ON RARE NEUROLOGICAL DISEASES
The medical center has been chosen to lead one of seven national centers established by the National Institutes of Health to investigate especially rare diseases. The Rochester center, which will focus on three uncommon neurological disorders, will be funded with $6.25 million, part of $51 million put forth by NIH to establish the Rare Diseases Clinical Research Network. The centers will focus on disorders that are often pushed aside in the fight for attention and dollars by more common diseases that affect millions of people, such as cancer, diabetes and heart disease. The Rochester center will be led by Robert Griggs, professor and chair of the Department of Neurology. It was Griggs who, 10 years ago, coined the word “channelopathies” to describe diseases caused by abnormal cell channels or gates that regulate the levels of crucial chemicals such as sodium, calcium, and potassium in our cells. Griggs’ center will focus on three channelopathies: periodic paralysis, episodic ataxia, and nondystrophic myotonias. In all three disorders, symptoms are sporadic, triggered in unpredictable ways by factors such as sleep, rest, exercise, diet, being startled, or feeling warm or cold. A patient with periodic paralysis, for instance, might be absolutely fine for years, and then suddenly wake up unable to move a muscle for hours. Other patients might become paralyzed for a few minutes several times every day. The three disorders are so rare, with perhaps a total of 10,000 patients in the United States, that most doctors never see a single case in a lifetime of practice. Many patients go from doctor to doctor for years before receiving a correct diagnosis from a specialist such as Griggs, who is sought out by patients around the globe who have rare neuromuscular disorders.
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