September 14, 2008, 10:30 PM CT
Depressed dialysis patients more likely to be hospitalized
Dr. Susan Hedayati, assistant professor of internal medicine, has demonstrated that depressed patients undergoing dialysis are nearly twice as likely to be hospitalized or die within a year than those who are not depressed.
Dialysis patients diagnosed with depression are nearly twice as likely to be hospitalized or die within a year than those who are not depressed, a.
UT Southwestern Medical Center researcher has found.
In the study, available online and in the Sept. 15 issue of Kidney International, scientists monitored 98 dialysis patients for up to 14 months. More than a quarter of dialysis patients received a psychiatric diagnosis of some form of depression based on a Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM IV).
This is the first reported link between adverse clinical outcomes in dialysis patients and depression made through a formal psychiatric interview based on the DSM-IV standards. More than 80 percent of the depressed patients died or were hospitalized, compared with 43 percent of non-depressed patients. Cardiovascular events, which previously have been associated with depression, led to 20 percent of the hospitalizations.
"Twenty percent of patients who start dialysis will die by the end of the first year," said Dr. Susan Hedayati, assistant professor of internal medicine and the study's lead author. "What we don't know yet is, if their depression is treated, could it extend dialysis patients' survival and improve their quality of life".........
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September 14, 2008, 10:13 PM CT
Tuberculosis drug shows promise against latent bacteria
A new study has shown that an investigational drug (R207910, currently in clinical trials against multi-drug resistant tuberculosis strains) is quite effective at killing latent bacteria. This revelation suggests that R207910 may lead to improved and shortened therapys for this globally prevalent disease.
Despite numerous therapy advances, tuberculosis (TB) remains a serious disease fueled by co-infection of HIV patients, the rise of drug-resistant strains, and the ability of Mycobacterium tuberculosis
to become dormant and linger in the lungs. In fact, one third of the world population is infected, asymptomatically, with latent TB and is at risk of developing active TB disease during their life time.
Anil Koul and his colleagues at Johnson & Johnson tested R207910 on dormant M. tuberculosis
in three different laboratory models of latency. R207910 targets a protein (ATP synthase) essential for making cellular energy (ATP) in actively replicating TB. The scientists reasoned that even dormant bacteria, which are essentially physiologically "turned off", still need to produce small quantities of ATP to survive. As such, a block in ATP synthesis might be an Achilles heel for killing dormant bacteria.
This reasoning proved to be correct and R207190 was able to kill dormant bacteria by greater than 95% whereas current drugs like isoniazid had no effect. Surprisingly, they observed that R207910 is slightly more effective in killing dormant bacteria as in comparison to actively replicating ones, a unique spin as all known TB drugs are more effective on replicating bugs. Koul and his colleagues hope to validate these results clinically, and note that ATP synthase should be looked at as a drug target for other persistent bacterial infections.........
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September 14, 2008, 10:09 PM CT
Cancer-causing gene in many colon cancers
Demonstrating that despite the large number of cancer-causing genes already identified, a number of more remain to be found, researchers at Dana-Farber Cancer Institute have linked a previously unsuspected gene, CDK8, to colon cancer.
The discovery of CDK8's role in cancer was made possible by new tools for assessing the activity of specific genes, say the authors of the new study. As these tools are further improved, the stream of newly discovered cancer genes is expected to increase, providing new avenues for treatment, the authors suggest. The findings are being published as an advanced online publication by the journal Nature
on Sept. 14.
"This study provides confirmation that a number of of the genes involved in cancer have yet to be identified," remarked the study's senior author, William Hahn, MD, PhD, of Dana-Farber and the Broad Institute of Harvard and M.I.T. "When it comes to identifying gene targets for treatment, we've really only scratched the surface".
The study is noteworthy in another respect, as well, the authors indicated. A number of of the abnormal proteins associated with cancer are known as "transcription factors" because they're able to "read" cell DNA and use that information for producing other cell proteins. Eventhough transcription factors are important regulators, this class of proteins has proven to be impossible to target with drugs. Genes that influence such transcription factors, however, make attractive targets for drugs, since they can potentially disrupt the cancer process and disable tumor cells. CDK8 is such a gene.........
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September 14, 2008, 10:08 PM CT
Faster, cheaper way of analyzing the human genome
Investigators at the Translational Genomics Research Institute (TGen) today announced a faster and less expensive way for researchers to find which genes might affect human health.
Using bar-codes, not unlike what shoppers find in grocery stores, TGen scientists found a way to index portions of the nearly 3-billion-base human genetic code, making it easier for researchers to zero in on the regions most likely to show variations in genetic traits.
The findings were published recently in the online version of the journal Nature Methods
The study will be published in print in the journal's October edition.
Dr. David Craig, associate director of TGen's Neurogenomics Division, said the new method should cost only one-tenth, or less, of the current cost of sequencing genes usually done to analyze Single Nucleotide Polymorphisms (SNPs), and in performing Genome-Wide Association (GWA) studies.
"Our goal is to find the genetic basis of disease,'' said Craig, the study's lead author. "It (the new method) provides us a way to immediately use next-generation sequencing technology for studying hundreds to thousands of individuals.''.
John Pearson, the head of TGen's Bioinformatics Research Unit, said the new method would allow researchers worldwide to more easily tune their sequencing experiments, and conduct their experiments with greater speed.........
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September 11, 2008, 9:47 PM CT
The pepperoni pizza hypothesis
What's the worst that could happen after eating a slice of pepperoni pizza? A little heartburn, for most people.
But for up to a million women in the U.S., enjoying that piece of pizza has painful consequences. They have a chronic bladder condition that causes pelvic pain. Spicy food -- as well as citrus, caffeine, tomatoes and alcohol-- can cause a flare in their symptoms and intensify the pain. Scientists had long believed the spike in their symptoms was triggered when digesting the foods produced chemicals in the urine that irritated the bladder.
A surprising new discovery from Northwestern University's Feinberg School of Medicine reveals the symptoms -- pain and an urgent need to frequently urinate -- are actually being provoked a surprise perpetrator. It's the colon, irritated by the spicy food, that's responsible. The finding provides an explanation for how the body actually "hears" pelvic pain.
The discovery also opens up new therapy possibilities for "painful bladder syndrome," or interstitial cystitis, a condition that primarily affects women (only 10 percent of sufferers are men.) During a flare up, the pelvic pain is so intense some women inject anesthetic lidocaine directly into their bladders to get relief. Patients typically also feel an urgent need to urinate up to 50 times a day and are afraid to leave their homes in case they can't find a bathroom.........
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September 11, 2008, 9:43 PM CT
Internet-based health-care teaching
A study led by a team of education scientists from Mayo Clinic and published this week in the Journal of the American Medical Association
) concludes that Internet-based education generally is effective.
Lead author David Cook, M.D., an associate professor of medicine who practices general internal medicine at Mayo Clinic, worked with scientists from Mayo and McMaster University in Hamilton, Ontario. They evaluated more than 200 studies about Internet-based instruction. The scientists concluded that Internet-based instruction is linked to large learning gains compared with no instruction. The research also showed that Internet-based instruction compared favorably to traditional instructional methods.
"Our findings suggest that Internet-based instruction is an effective way to teach health care professionals," says Dr. Cook. "We now can confirm that, across a wide variety of learners, learning contexts, clinical topics, and learning outcomes, Internet-based instruction can be as effective as traditional methods."
Dr. Cook also notes that Internet-based instruction has unique advantages, including flexible scheduling, adaptability of instruction, and readily available content that is easily updated. "As health care workers balance challenging practice demands, the ever-expanding volume of medical knowledge requires us to find more effective, efficient ways to learn," says Dr. Cook. "Internet-based instruction will be an important part of the solution".........
Posted by: Janet Read more Source
September 11, 2008, 9:39 PM CT
Developing Drug to Stop Cancer Recurrence
After years of working toward this goal, researchers at the OU Cancer Institute have found a way to isolate cancer stem cells in tumors so they can target the cells and kill them, keeping cancer from returning.
A research team led by Courtney Houchen, M.D., and Shrikant Anant, Ph.D., discovered that a particular protein only appears in stem cells. Until now, scientists knew of proteins that appeared in both regular cancer cells and stem cells, but none that just identified a stem cell.
The group has already begun work to use the protein as a target for a new compound that once developed would kill the stem cells and kill the cancer. By targeting the stem cells, researchers and physicians also would be able to stop the cancer from returning.
Houchen and Anant are focusing on adult cancer stem cells because of the major role they play in the start of cancer, the growth of cancer, the spread of cancer and the return of cancer.
Current therapies generally do not target stem cells in tumors. This allows stem cells to wait until after chemotherapy or radiation therapys to begin dividing. Scientists believe these stem cells are often responsible for the return of cancer after therapy. The identification of the stem cell marker enables scientists to develop new therapeutics that can target these cells.........
Posted by: Janet Read more Source
September 11, 2008, 9:34 PM CT
Mate selection more biologically determined
Some human populations may rely on biological factors in addition to social factors when selecting a mate. In a recent study, published September 12 in the open-access journal PLoS Genetics,
researchers in China, France, and the United Kingdom report genomic data showing that immunity traits may be involved in mate choice in some human populations.
In several species it has been shown that the Major Histocompatibility Complex (MHC), a large genomic region involved in immune response, influences mating selections and that this may be mediated by preferences based on body odor. Some prior studies have reported a tendency for humans to prefer MHC-dissimilar mates, encouraging heterozygosity at MHC loci in offspring and resulting in improved immune response. However, other studies, both directly in couples and also indirectly in "sweaty T-shirts" experiments, have reported conflicting results.
Adding to this debate is the recent study by Raphalle Chaix, Chen Cao and Peter Donnelly. The testing employed genome-wide genotype data and HLA types in a sample of African and a sample of European American couples, enabling the scientists to distinguish MHC-specific effects from genome-wide effects. The group examined whether husband-wife couples were more MHC-similar or MHC-dissimilar compared to random pairs of individuals.........
Posted by: Janet Read more Source
September 11, 2008, 9:25 PM CT
Rural HIV care has economic and health implications
An Indiana University study observed that HIV care providers in rural Indiana report significant stigma and discrimination in the rural medical referral system surrounding issues of HIV and substance abuse. Providers felt that these factors impeded their ability to offer quality care to their patients.
"The findings of this study demonstrate inefficiencies in our public health care system and our inability to link people easily to a range of health care providers in rural areas," said Michael Reece, lead investigator of the study and director of The Center for Sexual Health Promotion in Indiana University Bloomington's School of Health, Physical Education and Recreation. "This also has an important economic impact given that our investments in the public health system may not be achieving the outcomes we need, such as improvements in health status."
While most studies involving HIV and stigma rely on patient perspectives, this study focused solely on the perspectives of providers serving rural Indiana residents. Providers reported that some rural physicians refused to provide care for their patients. They also reported widespread stigmatizing comments and behavior from the rural medical community.
The study, "HIV Provider Perspectives: The Impact of Stigma on Substance Abusers Living with HIV in a Rural Area of the United States," appears in the latest issue of the journal AIDS Patient CARE and STDs. For Reece, focusing research locally is important.........
Posted by: Mike Read more Source
September 11, 2008, 9:21 PM CT
Keeping nerve axons on target
When immature neurons are placed on a microscopic running track, where flanking lanes are carpeted with repellant factors, their growing axons remain in their lanes (top). Neurons from mice lacking p75 are unreceptive to repulsive cues: when placed on the track, their axons meander all over the field, crossing lanes and running down repellant-covered stripes (bottom).
Credit: Courtesy of Dr. Yoo-Shick Lim, Salk Institute for Biological Studies
Neurons constituting the optic nerve wire up to the brain in a highly dynamic way. Cell bodies in the developing retina sprout processes, called axons, which extend toward visual centers in the brain, lured by attractive cues and making U-turns when they take the wrong path. How they find targets so accurately is a central question of neuroscience today.
Using the mouse visual system, a team of Salk Institute for Biological Studies researchers led by Dennis O'Leary, Ph.D., identified an unanticipated factor that helps keep retinal axons from going astray. They report in the Sept. 11 issue of Neuron
that p75, a protein previously known to regulate whether neurons live or die, leads a double life as an axon guidance protein.
"Historically, we thought that factors that mediate cell survival and those controlling axon guidance were part of two separate processes," says O'Leary, a professor in the Molecular Neurobiology Laboratory, "But in this study we show a direct interaction between these two systems".
Collaborating with Kuo-Fen Lee, Ph.D., professor in the Clayton Foundation Laboratories for Peptide Biology, the O'Leary team observed a defect in mice genetically engineered to lack p75. Through their synaptic connections, retinal axons develop a two-dimensional map of the retina in their targets in the brain. In the mice lacking p75, retinal axons stopped short of their final target and formed a map that was shifted forward to the superior colliculus, a major visual center in the brain.........
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