August 14, 2006, 11:40 PM CT

West Nile Virus Antibody Binding Site

Researchers have learned the precise location where an antibody binds to the West Nile virus, and they have suggested a mechanism for how this antibody neutralizes the virus to prevent infection.

"Science doesn't yet fully understand exactly how neutralizing antibodies work," said Michael Rossmann, the Hanley Distinguished Professor of Biological Sciences in Purdue's College of Science. "This work has shown precisely where the antibody binds to the virus, and we now have a theory for how it interacts with the virus to disarm it. Perhaps we are starting to understand why this particular antibody can inhibit the infectivity of the virus, which is important to understand if a vaccine is going to be developed".

Purdue worked with researchers from the Washington University School of Medicine in St. Louis.

West Nile belongs to a family of viruses known as flaviviruses, which includes a number of dangerous insect-borne disease-causing viruses. The antibody attaches to a protein called an E protein, for envelope protein, which makes up the virus's outer shell. There are 180 copies of E proteins symmetrically arranged in 60 sets of three, forming a geometric shape called an icosahedron, which is made up of triangular facets.

The researchers, however, were surprised to discover that this antibody recognizes only two of the E proteins in each set of three, said Bärbel Kaufmann, a postdoctoral research associate working in the Rossmann lab.........

Posted by: Rose      Permalink         Source

August 14, 2006, 10:13 PM CT

Hearing loss and high-speed dental tools

After 36 years in private dental practice, Fred Kreutzer, D.M.D., began struggling to hear. It's been five years since he retired from his practice and Kreutzer now wears hearing aids in both ears. Eventhough he has a family history of hearing loss, he believes the high-speed tools he worked with eight hours a day for so a number of years may have played a role in his hearing troubles. "I think if you listen to any high-pitched noise for any length of time, it will get to you eventually," said Kreutzer, an assistant professor in operative dentistry at the OHSU School of Dentistry (www.ohsu.edu/sod). "But in my case, with a family history of hearing loss, it may be hereditary, as well".

Whether high-speed dental tools contribute to long-term hearing loss is the subject of a study currently under way in the OHSU Tinnitus Clinic and the School of Dentistry. As per Robert Folmer, Ph.D., one of the study leaders, published research is mixed about whether high-speed dental tools contribute to noise-induced hearing loss over time.

"Over the years, we have seen dentists in the OHSU Tinnitus Clinic who were convinced that long-term exposure to sound from high-speed hand pieces contributed to their high-frequency hearing loss and tinnitus," said Folmer. "These anecdotes, in combination with the research being divided about high-speed hand pieces playing a role in hearing loss, prompted our study. We hope the study is a good first step toward scientific evidence behind the anecdotes we've been hearing." Fulmer is associate professor of otolaryngology/head and neck surgery, School of Medicine, and chief of clinical services at the OHSU Tinnitus Clinic, Oregon Hearing Research Center.........

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August 13, 2006, 6:22 PM CT

Cause Of Neurodegenerative Disease

When a faulty protein wreaks havoc in cells and causes disease, scientists are commonly quick to point the finger at a wayward gene. Now researchers are learning that some neurodegenerative diseases can develop even though a gene is perfectly normal. The diseases can be caused when the genetic instructions contained in the gene are not executed properly, leading to a lethal buildup of malformed proteins in brain cells.

The new studies by Howard Hughes Medical Institute (HHMI) investigator Susan L. Ackerman and his colleagues at The Jackson Laboratory point to a novel mechanism behind the buildup of the toxic sludge that accumulates in neurons. Scientists have long known that neurodegenerative disorders can be caused by the gradual yet persistent accumulation of misfolded proteins in neurons that eventually triggers cell death. But this new mechanism points to errors in executing the genetic instructions, which are distinct from known causes of neurodegenerative diseases, such as Alzheimer's and Huntington's diseases.

HHMI investigator Susan L. Ackerman and her colleagues reported their findings in an August 13, 2006, advance online publication of the journal Nature. Ackerman's group collaborated on the studies with co-author Paul Schimmel at The Scripps Research Institute.........

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August 11, 2006, 0:04 AM CT

Advances In Bipolar Disorder Treatment

A new care model for bipolar disorder tested in veterans across the nation reduced their manic episodes and improved their quality of life, according to research led by a psychiatrist with the Providence Veterans Affairs Medical Center and Brown Medical School.

The randomized, controlled trial also showed that the model did not add to the treatment costs for bipolar disorder, which affects nearly 6 million American adults a year. Results appear in two reports published in Psychiatric Services, a journal of the American Psychiatric Association.

"We applied the same symptom management approaches found in interventions for diabetes and asthma to the treatment of bipolar disorder and found that people with serious mental illness can help take control of their care," said Mark S. Bauer, M.D., staff psychiatrist with the Providence V.A. Medical Center and professor of psychiatry and human behavior at Brown Medical School. "This finding should reduce the stigma of helplessness that so often is associated with these disorders, and it will open new avenues for the treatment of bipolar disorder".

Bauer oversaw the clinical trial and is the lead author of both journal articles.

The new model was developed and tested in veterans with bipolar disorder at the Providence V.A. Medical Center. During the trial, 306 veterans were enrolled at 11 V.A. centers located in Arizona, California, Colorado, Georgia, Indiana, Maryland, Ohio, Pennsylvania, Tennessee and Texas. Each veteran was randomly assigned to a study group. One group got usual care through their psychiatrist. The other group received treatment under the new model.........

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August 9, 2006, 10:28 PM CT

Behaviors That Can Lead To Poor Health

Adolescents who feel dissatisfied with their bodies are at higher risk for future binge eating, smoking, poor eating, and decreased physical activity, as per new research from the University of Minnesota School of Public Health.

A study reported in the August 2006 issue of the Journal of Adolescent Health found lower levels of body satisfaction among teenagers can predict the use of unhealthy weight control behaviors, which can lead to weight gain and poorer overall health.

Teenage girls who weren't satisfied with their bodies were more likely to binge eat, participate in less physical activity, eat less fruits and vegetables, take diet pills, and induce vomiting five years later. Adolescent boys with low body satisfaction were also more prone to these unhealthy habits and more likely to start smoking in the future. In contrast, teenagers with a positive body image were more likely to take care of themselves through healthy eating and exercise.

"This study shows that teens who have negative feelings about their bodies don't turn to healthy weight management," said Dianne Neumark-Sztainer, Ph.D., M.P.H., R.D., lead author and professor of epidemiology at the University of Minnesota School of Public Health. "Instead, they use weight control behaviors that put them at a higher risk for obesity and poor health down the road. With this in mind, interventions with teens should strive to boost self-confidence so they will want to take care of themselves the right way".........

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August 8, 2006, 9:38 PM CT

Exploring Alzheimer's Causes

Some people live to be 100 without falling victim to Alzheimer's disease. Li-Huei Tsai, who joined MIT this spring as Picower Professor of Neuroscience, wants to know why.

Amyloid beta or Abeta (a protein fragment that accumulates in the brains of Alzheimer's patients) is a telltale sign of the disease, which affects 4 million Americans, most over age 65. Normally, the body manages to break down and eliminate these fragments, but in the aging brain, they tend to form insoluble plaques.

To add to the mystery, some people function relatively normally with plaques nestled among their neurons, while others are virtually incapacitated. "There are people with a significant plaque load who can keep up with their daily lives," said Tsai, who has appointments in the Department of Brain and Cognitive Sciences and at the Picower Institute for Learning and Memory. "Obviously, other factors are determining whether they have full-blown Alzheimer's".

Tsai, who as a child in Taipei witnessed her beloved grandmother's descent into dementia, is determined to unravel the thorny questions associated with neurodegenerative and psychiatric disorders.

Tsai uses a combination of molecular, cellular and biochemical approaches to study Alzheimer's disease and psychiatric and developmental disorders. She focuses on a kinase (kinases are enzymes that change proteins) called Cdk5. Cdk5, paired with the protein p35, helps new neurons form and migrate to their correct positions during brain development. But Cdk5, paired with an aberrant form of p35 called p25, also is implicated in age-related neurodegenerative diseases.........

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August 8, 2006, 8:38 PM CT

High Blood Pressure Induces Low Fat Metabolism

"The heart is the single most energy-consuming organ per weight in the body," says Lisa de las Fuentes, M.D.

Under some conditions this energy-hungry organ is prone to defects in its energy metabolism that contribute to heart disease, according to research published in a recent issue of the Journal of Nuclear Cardiology by de las Fuentes and colleagues at Washington University School of Medicine in St. Louis.

Earlier research led by de las Fuentes' colleague Robert J. Gropler, M.D., showed that heart muscle in people with diabetes is overly dependent on fat for energy. Even though fat is an efficient fuel, burning it for energy creates an unusually high demand for oxygen, making the diabetic heart more sensitive to the drops in oxygen levels that occur with coronary artery blockage.

Gropler is director of the Cardiovascular Imaging Laboratory at the Mallinckrodt Institute of Radiology at the School of Medicine and professor of radiology, medicine and biomedical engineering.

Now this group of Washington University researchers has shown that hearts of non-diabetics with muscle thickening due to high blood pressure have an energy metabolism skewed in the opposite direction - away from the use of fat for energy.

"Whereas Dr. Gropler found that a high level of fatty acid metabolism could be detrimental, we show that a low level may also be harmful," says de las Fuentes, co-director of the Cardiovascular Imaging and Clinical Research Core Laboratory and assistant professor of medicine. "These findings aren't contradictory. The heart has to be able to choose the energy source, either fats or glucose, most appropriate for its current energy needs and the availability of fuel".........

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August 8, 2006, 0:31 AM CT

System To Put Wastewater To Work

In the midst of the worldwide energy crisis, researchers at Washington University in St. Louis have been continuing their work on a microbial fuel cell that generates electricity from wastewater. Advances in the design of this fuel cell in the last year have increased the power output by a factor of 10 and future designs, already in the minds of the researchers, hope to multiply that power output by 10 times again. If that goal can be achieved, the fuel cell could be scaled up for use in food and agricultural industries to generate electrical power - all with the wastewater that today goes right down the drain.

Lars Angenent, Ph.D., assistant professor of chemical engineering, and a member of the University's Environmental Engineering Science Program, has devised a continually fed upflow microbial fuel cell (UMFC). In a paper published online in the Environmental Science Technology, Angenent describes how wastewater enters from the bottom of a system and is continuously pumped up through a cylinder filled with granules of activated carbon. Many previous microbial experiments used closed systems with a single batch of nutrient solution, but because this system is continuously fed from a fresh supply of wastewater, Angenent's UMFC has more applications for industry since wastewater is continually outputted during industrial production.........

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August 8, 2006, 0:00 AM CT

Best Memorization Strategies

Exploring exactly why some individuals' memory skills are better than others has led scientists at Washington University in St. Louis to study the brain basis of learning strategies that healthy young adults select to help them memorize a series of objects. Using functional magnetic resonance imaging (fMRI), the scientists uncovered brain regions specifically correlated with the diverse strategies that subjects adopt.

Brenda Kirchhoff, research associate in psychology in the University's School of Arts and Sciences, conducted this study in the then-Washington University lab of Randy L. Buckner, now a professor of psychology at Harvard University and investigator at the Howard Hughes Medical Institute. Their findings have been reported in the July 20, 2006, issue of Neuron. (Kirchhoff is the article's first author and Buckner is senior author.).

"Randy and I were interested in exploring individual differences in memory - why some people are better at learning new information than others," said Kirchhoff. "Our main goal was to determine the learning strategies that people use and their relationship to memory performance. Secondly, we wanted to know if individual differences in learning strategies were linked to individual differences in brain activity".

What they found was that test subjects used two main self-selected strategies to learn new information. Use of the strategies was linked to better memory performance. Furthermore, individual differences in learning strategies could be correlated with MRI-detected biological activity in distinct brain regions.........

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August 7, 2006, 11:40 PM CT

Surprise Finding For Stretched DNA

Most of us are familiar with the winding staircase image of DNA, the repository of a biological cell's genetic information. But few of us realize just how tightly that famous double helix is wound. Stretched to its full length, a single molecule of human DNA extends more than three feet, but, when wound up inside the nucleus of a cell, that same molecule measures about one millionth of an inch across. Biologists have long believed that as a molecule of DNA is stretched, its double helix starts to unwind. As much sense as this makes from an intuitive standpoint, a recent experiment proved it not to be the case.

Scientists with the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California at Berkeley used a combination of microscopic beads and magnetic tweezers to observe that when a DNA molecule is stretched, it actually begins to overwind. This overwinding continues until the force being applied to stretch the DNA exceeds about 30 picoNewtons. (One picoNewton is about a trillionth the force mandatory to hold an apple against Earth's gravity.) Beyond the 30 picoNewton threshold, the DNA double helix did begin to unwind in accordance with predictions.

"DNA's helical structure implies that twisting and stretching should be coupled, hence the prediction that DNA should unwind when stretched," said biophysicist Carlos Bustamante, who led this experiment. "That is why it was such surprise when we directly measured twist-stretch coupling to find instead DNA overwinds when stretched. The DNA molecule, when studied at close range, continues to surprise us!".........

Posted by: Rose      Permalink         Source

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