August 20, 2006, 2:10 PM CT

Technology For Brain Cooling Unlikely To Help Trauma Patients

Attempts to cool the brain to reduce injury from stroke and other head trauma may face a significant obstacle: current cooling devices can't penetrate very deeply into the brain.

Researchers at Washington University School of Medicine in St. Louis used rats to validate a "cold shielding" effect of blood flow that they previously predicted theoretically. The shielding effect, created by large quantities of warm blood that continually perfuse brain tissue, prevents a drop in temperatures around the head from penetrating beyond a certain depth in the brain.

A number of ongoing clinical trials try to reduce brain temperatures through cooling units incorporated into hats or other devices that surround the head. However, the new findings, published online this month in the Journal of Applied Physiology, suggest in most patients such techniques will be unable to defeat the natural temperature regulation built into the brain via the blood system.

"In adult humans, the characteristic length that this kind of cold assault appears to penetrate is approximately a tenth of an inch, leaving the temperature of approximately 6 inches of brain tissue unchanged," says senior author Dmitriy Yablonskiy, Ph.D., professor of radiology at the School of Medicine and of physics in Arts and Sciences. "Our findings suggest that the reason trials of this kind have so far produced inconsistent results is because we're not cooling enough of the brain."........

Posted by: Daniel      Permalink         Source

August 19, 2006, 9:24 PM CT

New Treatment For Dangerous Staph Infections

Duke University Medical Center scientists have demonstrated in an international clinical trial the effectiveness and safety of a new drug for treating bloodstream and heart infections caused by Staphylococcus aureus bacteria, a major cause of sickness and death worldwide.

Based on the trial, the Food and Drug Administration already has approved the drug -- daptomycin -- for treating heart infections and bacteremia, also known as bloodstream infection or blood poisoning, caused by S. aureus, as per Vance G. Fowler Jr., M.D., an associate professor of infectious diseases who took part in the study.

"This is the first new drug the FDA has approved in two decades for treating these types of potentially life-threatening infections," Fowler said. "This advance adds a new weapon to our dwindling arsenal of antibiotics against these difficult-to-treat infections."

Daptomycin had been approved by the FDA in 2003 for treating skin infections caused by S. aureus. But until now, Fowler said, no one knew definitively whether the drug would be effective against the more serious bloodstream and heart infections.

The scientists published their findings in the August 17, 2006, issue of the New England Journal of Medicine. Cubist Pharmaceuticals, which manufactures daptomycin, funded the study.........

Posted by: Mark      Permalink         Source

August 18, 2006, 6:37 AM CT

Core Needle Biopsy Gives An Accurate Picture

The gene expression profile detected in the core needle biopsy of a breast tumour is representative of gene expression in the whole tumour. A study published recently in the open access journal Breast Cancer Research confirms the reliability of core needle biopsy as a tool in breast cancer diagnosis and prognosis. The study also shows that the gene expression profile of a core needle biopsy might be more accurate than the profile of a surgical sample taken from the same tumour, after the biopsy was carried out. As per the study results, the biopsy procedure seems to trigger the expression of genes involved in wound healing as well as tumour invasion and metastasis, thus modifying the gene expression profile of subsequent surgical samples.

Rosanna Zanetti-Dällenbach from the Women's University Hospital in Basel, Switzerland and his colleagues from Stiftung Tumorbank, OncoScore AG and University Hospital in Basel, analysed the gene expression profile of core needle biopsies taken from 22 women diagnosed with breast cancer. For each woman, they compared the biopsy expression profile with the expression profile of a surgical sample taken from the tumour subsequently to the core needle biopsy. Zanetti-Dällenbach et al. quantified the expression of 60 genes known to be involved in breast tumour development using a technique called reverse polymerase chain reaction (PCR). Zanetti-Dällenbach et al. also analysed the gene expression profiles of surgical samples taken from the breast tumours of 317 patients who did not undergo a core needle biopsy.........

Posted by: Janet      Permalink         Source

August 17, 2006, 11:24 PM CT

Cause of Ischemic Stroke Analyzed

In contrast to traditional beliefs that stroke-causing clots derived from arterial and cardiac sources are distinctly different, a new UCLA study shows they are composed of similar components.

Scientists studied clots removed from the brain blood vessels of 25 stroke victims. The clots were retrieved during therapy using a novel mechanical clot-retrieval device called the MERCI (Mechanical Embolus Removal in Cerebral Ischemia) Retriever. The removed clots were analyzed under the microscope to compare their component structures.

"Unexpectedly, no two retrieved clots looked the same, even though all were constructed from the same basic components of fibrin, white cells and red blood cells," said lead author Dr. Victor Marder, professor of hematology and oncology at the David Geffen School of Medicine at UCLA and a UCLA Stroke Center member. "The same components were involved in both the newly formed and mature, enlarging clots. Red blood-cell accumulations had previously been considered to dominate the structure of clots that formed within a heart chamber, but our results suggest that red cells often accumulated on clots after impaction in the brain artery".

The findings could lead to better therapies to prevent clots, clear blockages and reverse strokes in the crucial first hours after they occur.........

Posted by: Daniel      Permalink         Source

August 14, 2006, 11:39 PM CT

West Nile Virus Antibody Binding Site

Scientists 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 scientists from the Washington University School of Medicine in St. Louis.

West Nile belongs to a family of viruses known as flaviviruses, which includes many 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: Mark      Permalink         Source

August 13, 2006, 6:26 PM CT

Life and death in the hippocampus

Whether newborn nerve cells in adult brains live or die depends on whether they can muscle their way into networks occupied by mature neurons. Neuroresearchers at the Salk Institute for Biological Studies pin-pointed the molecular survival gear mandatory for a young neuron to successfully jump into the fray and hook up with other cells.

As per a research findings published in a forthcoming issue of Nature, scientists in the lab of Fred H. Gage, Ph.D., a professor in the Gene Expression Laboratory and the Vi and John Adler Chair for Research on Age-Related Neurodegenerative Diseases, identify a subunit of the NMDA receptor, a protein complex that transduces signals sent by neighboring cells, as the cells' life-saving equipment that allows them to integrate into the existing brain circuitry.

The NMDA receptor is activated by the neurotransmitter glutamate, a chemical released by neurons in order to transmit information to neighboring cells. Whenever the receptor picks up a glutamate signal it is stimulated and relays the signal. But for newborn neurons that signal means something else entirely -- survival.

"When we removed the NMDA receptor, that is when cells make connections in response to glutamate in the environment, the newborn neurons withered and died at a specific stage of their maturation," explains Gage. " The NMDA receptor modulates synapse formation and determines what pattern of input activity new neurons receive, which in turn determines survival or death".........

Posted by: Daniel      Permalink         Source

August 13, 2006, 6:00 PM CT

Simplified Treatment Of HIV Infection

A preliminary study indicates that using a single boosted protease inhibitor instead of the standard regimen of 3 drugs for maintenance treatment may be an effective therapy for select patients with HIV infection, as per a research studyin the August 16 issue of JAMA, a theme issue on HIV/AIDS.

Susan Swindells, M.B.B.S., of the University of Nebraska Medical Center, Omaha, presented the findings of the study today at a JAMA media briefing at the International AIDS Conference in Toronto.

The long-term adverse effects, expense, and difficulty of sustained adherence to multidrug antiretroviral regimens have prompted studies of simpler therapies for human immunodeficiency virus type 1 (HIV-1) infection. Treatment cessation, intermittent treatment, and induction-maintenance (a few months of triple treatment followed by simplified treatment) regimens have been reviewed with mostly inferior results, as per background information in the article.

Dr. Swindells and his colleagues conducted a study to determine whether a simplified maintenance treatment with the antiretroviral medicine "boosted" atazanavir alone after virologic suppression (cessation of detectable HIV virus replication) would not markedly increase the risk of virologic failure. Protease inhibitors, such as atazanavir, are often combined with a small dose of ritonavir to increase blood levels a phenomenon known as "boosting." This regimen was selected because of low pill burden, once-daily dosing, safety, and unique resistance profile. The 24-week pilot study, conducted between Sept. 2004 and April 2006, included 36 HIV-infected adults with virologic suppression for 48 weeks or longer receiving their first protease inhibitor (PI)based regimen. Participants switched PIs to atazanavir-ritonavir at entry and discontinued nucleoside analog reverse transcriptase inhibitors (NRTIs) after 6 weeks. Virologic failure was defined as two consecutive HIV-1 RNA measurements of 200 copies/mL or more. The final analysis included 34 patients.........

Posted by: Mark      Permalink         Source

August 13, 2006, 9:39 AM CT

Adult Cells To Embryonic Stem Cells

With the introduction of just four factors, scientists have successfully induced differentiated cells taken from mouse embryos or adult mice to behave like embryonic stem cells. The scientists reported their findings in an immediate early publication of the journal Cell.

The cells--which the scientists designate "induced pluripotent stem cells" (iPS)--exhibit the physical, growth, and genetic characteristics typical of embryonic stem cells, they reported. "Pluripotent" refers to the ability to differentiate into most other cell types.

"Human embryonic stem cells might be used to treat a host of diseases, such as Parkinson's disease, spinal cord injury, and diabetes," said Shinya Yamanaka of Kyoto University in Japan. "However, there are ethical difficulties regarding the use of human embryos, as well as the problem of tissue rejection following transplantation into patients".

Those problems could be circumvented if pluripotent cells could be obtained directly from the patients' own cells.

"We have demonstrated that pluripotent stem cells can be directly generated from fibroblast cultures by the addition of only a few defined factors," Yamanaka said. Fibroblasts make up structural fibers found in connective tissue.

Embryonic stem cells are derived from inner cells of the mammalian blastocyst, a ball of cells that develops after fertilization and goes on to form a developing embryo. Cells from other parts of the body can also be "reprogrammed" by transferring their nuclear contents into egg cell precursors called oocytes or by fusion with embryonic stem cells, earlier studies showed.........

Posted by: Scott      Permalink         Source

August 11, 2006, 0:03 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, as per research led by a psychiatry expert 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 therapy 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 therapy of bipolar disorder and observed that people with serious mental illness can help take control of their care," said Mark S. Bauer, M.D., staff psychiatry expert 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 linked to these disorders, and it will open new avenues for the therapy 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 psychiatry expert. The other group received therapy under the new model.........

Posted by: JoAnn      Permalink         Source

August 10, 2006, 7:06 AM CT

Predictors Of Breast Cancer

Breast cancer scientists at the University of North Carolina at Chapel Hill have identified many activity patterns in the genes of individual tumors that make them biologically different from others. These findings could provide valuable clinical information such as how likely the tumors are to be invasive, how well they might respond to different therapys and how likely they are to recur or spread.

Currently, doctors treating patients with breast cancer make therapy decisions and predictions based largely on the location and size of the tumor and if the cancer has spread, or metastasized, to lymph nodes and distant sites of the body.

But not all patients who are similar in terms of these clinical indicators get the same benefits from therapy.

These new findings could remedy that situation. Such differences in gene activity may be used as biomarkers to identify which therapys can be individually matched.

Over the past five years, gene expression profiles have been identified that appear to be predictive for cancer patients, particularly for breast cancer patients. But these tests show very little overlap in their gene lists, and thus it is not known just how distinct these different assays might be.

As per Dr. Charles M. Perou, assistant professor of genetics and pathology at the UNC School of Medicine and a member of the UNC Lineberger Comprehensive Cancer Center, some of the predictive assays are available commercially and others are under study in clinical trials in which therapy decisions, including whether or not to use chemotherapy, are being made based on them.........

Posted by: Janet      Permalink         Source