January 8, 2007, 9:08 PM CT

Limited Options For Backup Hiv Treatment

Thai researchers have discovered that patients who fail treatment with a commonly used, inexpensive, first-line antiretroviral therapy (ART) are also usually resistant to other, similar drugs, leaving progressively fewer options for replacement therapies. Since catching treatment failure early is key to preventing further resistance, this research, published in the Feb. 1 issue of Clinical Infectious Diseases and currently available online, also argues for greater access in the developing world to tests that detect when the amount of virus in a patient's blood is increasing.

Combined antiretroviral therapy has dramatically changed the course of HIV disease, with a substantial reduction in illness and death both in developed and in developing nations. In Thailand, where a 2004 estimate put the number of HIV-infected people at 600,000, a generic, fixed-dose, combined pill of three antiretroviral agents has been available since 2002. In 2004, it was estimated that 60,000 Thai citizens would take this combination of stavudine, lamivudine, and nevirapine, known as d4T/3TC/NVP.

Lead author Somnuek Sungkanurparph, MD, of Ramathibodi Hospital in Thailand, and co-authors found that when this combination stopped working, it was nearly always because the virus had developed mutations that also make useless several other drugs of the same type.........

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January 7, 2007, 9:33 PM CT

The Molecular Basis Of Memory

Phone numbers, the way to work, granny's birthday -- our brain with its finite number of nerve cells can store incredible amounts of information. At the bottom of memory lies a complex network of molecules. To understand how this network brings about one of the most remarkable capacities of our brain we need to identify its components and their interactions. Researchers from the European Molecular Biology Laboratory's (EMBL) Mouse Biology Unit in Monterotondo, Italy, and the Universidad Pablo de Olavide in Sevilla, Spain, now for the first time investigate the molecular basis of memory in living mice. The study, which appears in the current issue of Learning and Memory, identified a molecule that is crucially involved in learning and singled out the signaling pathway through which it affects memory.

Our sense organs inform our brain about what happens around us and brain cells communicate this information between each other using electrical signals. These signals become stronger the more often a cell experiences the same stimulus allowing it to distinguish familiar information from news. In other words a cell remembers an event as an unusually strong and long-lasting signal. This phenomenon called long-term potentiation (LTP) is thought to underpin learning and memory and its molecular basis is being investigated intensively.........

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December 26, 2006, 7:45 PM CT

Osteoporosis Drug Can Discontinued

A long-term study of the most widely used osteoporosis drug has found that many women can discontinue the drug after five years without increasing their fracture risk for as long as five more years.

The study on alendronate was led by researchers at the University of California, San Francisco, and findings are reported in the December 27, 2006 issue of the "Journal of the American Medical Association." The research also showed that women at very high risk of painful spine fractures might be better-off continuing treatment.

"This has important implications as it has not been known whether treatment of osteoporosis should be continued indefinitely," said lead author Dennis Black, PhD, professor in the UCSF Department of Epidemiology and Biostatistics. "Because women with osteoporosis, particularly older post-menopausal women, often need to take multiple drugs, this would be welcome news for this group".

According to Black, shorter term studies of up to five years duration have shown reductions in fracture risk with alendronate treatment. This was the first study to examine the effects on fracture using the drug longer than five years, he said.

"We found that women who discontinued the drug had the same rate of non-spine fractures as women who continued using the drug," he said. "However, for clinically-recognized spine fractures, usually discovered due to back pain, continuing alendronate was better than discontinuing. And, if women choose to continue, we showed that 10 years of treatment is safe".........

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December 20, 2006, 4:30 AM CT

Those Blood Transfusions During Heart Bypass Surgery

Blood transfusions save the lives of millions of heart surgery patients and others each year. But a new study suggests that patients who receive transfusions during heart bypass surgery have a higher risk of developing potentially dangerous infections, and dying, after their operation.

In fact, this increased risk may help explain a longstanding medical mystery: why women bypass patients are more likely than men to die in the first few months after surgery. Women are more likely to receive blood during heart bypass operations, which are performed on more than 465,000 Americans each year.

The findings, from the Patient Safety Enhancement Program (PSEP) at the University of Michigan Health System, are based on data from 9,218 Michigan bypass patients. After adjusting for factors such as the urgency of the operation, those who received blood transfusions from donors were five times more likely to die within 100 days of their operation than those who did not.

The paper is reported in the recent issue of the American Heart Journal. It builds on a prior U-M analysis that observed that a difference in infection rates accounted for the difference in death risk between men and women bypass patients.

The U-M team, with the help of Neil Blumberg, M.D., of the University of Rochester Medical Center, focused on blood transfusions as a contributing factor. Previous research has shown that recipients of stored donor blood have more post-surgical infections, and that women receive more transfusions because they tend to have lower hemoglobin concentrations.........

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December 15, 2006, 5:14 AM CT

Learning During Sleep?

The question of how the brain stores or discards memories still remains largely unexplained. A number of brain scientists regard the consolidation theory as the best approach so far. This states that fresh impressions are first stored as short-term memories in the hippocampus. They are then said to move within hours or a few days - commonly during deep sleep - into the cerebral cortex where they enter long-term memory. Investigations by Thomas Hahn, Mayank Mehta and the Nobel Prize winner Bert Sakmann from the Max Planck Institute for Medical Research in Heidelberg have now shed new light on the mechanisms that create memory. As per their findings, the areas of the brain work together, but possibly in a different way from that previously assumed. "This is a technically sophisticated study which could have considerable influence on our understanding of how nerve cells interact during sleep consolidation," confirmed Edvard Moser, Director of the Centre for the Biology of Memory in Trondheim, Norway.

It has been difficult up to now to use experiments to examine the brain processes that create memory. The researchers in Heidelberg developed an innovative experimental approach particularly for this purpose. They succeeded in measuring the membrane potential of individual interneurones (neurones that suppress the activity of the hippocampus) in anaethetised mice. At the same time, they recorded the field potential of thousands of nerve cells in the cerebral cortex. This allowed them to link the behaviour of the individual nerve cells with that of the cerebral cortex. The scientists discovered that the interneurones they examined are active at almost the same time as the field potential of the cerebral cortex. There was just a slight delay, like an echo.........

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December 13, 2006, 6:23 PM CT

New Tool To Halt Recurrence Of Atrial Fibrillation

Clinical researchers at the University of Pennsylvania Health System are starting a trial utilizing a new mechanism to treat the heart when its electrical pulses essentially short-circuit, referred to as atrial fibrillation (A-Fib).

The biggest problem physicians run into with current therapies to cope with electrical rhythmic pumping problems in the heart, namely pulmonary vein isolation procedures, is that up until now, they've had to deliver the energy bursts to the tissue in a dot-by-dot catheter ablation procedure around the veins, almost like a string of pearls. "That can cause swelling, and when that swelling goes down, you may still have viable tissue left behind, gaps, where the electricity can still conduct itself or get through," explains David Callans, MD, director of the electrophysiology laboratory at the Hospital of the University of Pennsylvania and principal investigator of this study. "Now we have a mechanism to construct this barricade of lesions, to do an entire circular ablation, minimizing the potential for gaps behind in the pulmonary veins".

Cardiac electrophysiologists at Penn are now using a high intensity focused ultrasound (HIFU) ablation system. It's the first to deliver energy bursts forward in a complete circle, all at once, from outside of the vein. This invasive procedure is done in the lab with balloon catheters while the patient is awake but sedated.........

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December 11, 2006, 4:58 AM CT

Challenging The Theory Of Memory Storage

Daily events are minted into memories in the hippocampus, one of the oldest parts of the brain. For long-term storage, scientists believe that memories move to the neocortex, or "new bark," the gray matter covering the hippocampus. This transfer process occurs during sleep, especially during deep, dreamless sleep.

Many neuroscientists have embraced and built upon this theory of memory storage, or consolidation, for a generation. But the theory is difficult to test. New research led by Brown University neuroscientist Mayank Mehta, conducted with Nobel Prize-winning physiologist Bert Sakmann, shows the best evidence yet of the sleep dialogue between the old brain and the.

Their work, published in Nature Neuroscience, also shows that this interaction occurs in a startling way. Instead of the hippocampus uploading information to the neocortex in a burst of brain cell communication, Mehta found the opposite: the neocortex seems to drive the dialogue with the hippocampus.

The findings may give scientists a new understanding of how the brain manages memories in health and during dementia, offering up a fresh look at the causes of diseases such as Alzheimer's, as well as potential treatments.

"Long-term memory making may be a very different process than we previously thought," said Mehta, an assistant professor in the Department of Neuroscience at Brown. "Either this reversed dialogue is, somehow, a part of memory storage or this transfer of information from the old to the new brain may not occur during sleep. Either way, the results call into question commonly held theories about the role of cortico-hippocampal dialogue in sleep".........

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December 6, 2006, 8:09 PM CT

Asian Immigrants Have Fewer Mental Health Problems

Immigrants from Asia have lower rates of psychiatric disorders than American-born Asians and other native-born Americans, according to the first national epidemiological survey of Asian Americans in the United States.

The study showed different mental health patterns among women and men, with birthplace the key factor for women and English-language proficiency the main variable among men. Asian-American immigrant women were far less likely to suffer from a depressive, anxiety, substance abuse or psychiatric disorder in their lifetime than were U.S.-born women. Immigrant men who reported good or excellent English skills were less likely to have mental health problems than were those who had poorer English proficiency or American-born men.

"Compared to all Americans, Asian Americans had lower lifetime rates of any disorder," said David Takeuchi, a sociologist and University of Washington social work professor and lead author of the study. "Roughly 48 percent of Americans will have some kind of a lifetime disorder. In our study, less than one in four Asian-American immigrants will have a disorder. However, that won't necessarily be the case for their children and grandchildren. If trends continue, rates for them will go up and that suggests that more investment is needed for prevention programs".........

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December 5, 2006, 9:06 PM CT

Concerned About After-School Care

Millions of working fathers and mothers are less productive at work due to concerns about what their children are doing in the after-school hours, according to a new study released recently by Catalyst, the leading nonprofit research and advisory organization working to build inclusive environments and expand opportunities for women at work. The report, entitled After-School Worries: Tough on Parents, Bad for Business, was conducted in cooperation with the Women's Studies Research Center at Brandeis University.

The study outlines many factors that contribute to employed parents' concern about the after-school hours (called "PCAST," for Parental Concern about After-School Time) and the consequences both for parents and their employers. Though a majority of working parents are faring well, the report finds that both men and women are vulnerable at significant levels to the negative consequences of PCAST, which potentially affects one-third of the labor force, based on census data. (1).

"Our findings show that PCAST can be very toxic to employee attitudes, work performance and well-being," said Karen Gareis, a social psychologist at Brandeis' Women's Studies Research Center and a lead researcher on the study. "However, companies can help all employeesnot just parentsperform at their most productive level without breaking the bank. By giving employees greater job control and cultivating a results-oriented agile workplace,' companies can benefit their bottom line as well as their employees".........

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December 5, 2006, 8:33 PM CT

How Taste Develops

Scientists at the University of Pennsylvania School of Medicine have come one step closer to understanding how the sense of taste develops. They have pinpointed a molecular pathway that regulates the development of taste buds. Using genetically engineered mice, they discovered that a signaling pathway activated by small proteins called Wnts is mandatory for initiating taste-bud formation. They have also determined that Wnt proteins are mandatory for hooking up the wiring of taste signals to the brain.

Senior author Sarah E. Millar, PhD, Associate Professor in the Departments of Dermatology and Cell and Developmental Biology, Penn postdoctoral fellow Fei Liu, PhD, and his colleagues report their findings in the most recent online issue of Nature Genetics. "The developmental biology of taste is underexplored," says Millar of her team's impetus for the study.

The scientists demonstrated that blocking the action of Wnt proteins in surface cells of the developing tongue prevents taste-bud formation, while stimulating Wnt activity causes the formation of excessive numbers of enlarged taste papillae that are able to attract taste-related nerve fibers. This study represents the first genetic analysis of taste-organ initiation in mammals. While these studies were performed in mice, the scientists think that their findings will also hold true for understanding the basis of taste-bud development in humans.........

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