August 2, 2006, 11:33 PM CT

Mapping System For Skin Cells

Global-positioning system aficionados know that it's possible to precisely define any location in the world with just three geographic coordinates: latitude, longitude and altitude. Now researchers at the Stanford University School of Medicine have discovered that specialized skin cells use a similar mapping system to identify where they belong in the body and how to act once they arrive.

These cellular cornerstones direct embryonic patterning and wound healing by sending vital location cues to their neighbors, and may help in growing tissue for transplant or understanding metastatic cancer.

"There is a logic to the body that we didn't understand before," said John Rinn, PhD, a postdoctoral scholar in the laboratory of Howard Chang, MD, PhD, assistant professor of dermatology. "Our skin is actively maintaining itself throughout our life, and these 'address codes' help the cells know how to respond appropriately." Rinn is the first author of the research, which is reported in the current issue of Public Library of Science-Genetics.

Until now it's been a mystery as to how adult skin, which consists of basically the same components all over the body, knows to grow hair in some areas like the scalp, while manufacturing sweat glands, calluses and fingerprint whorls in others. In 1969, well-known developmental biologist Lewis Wolpert authored a famous treatise that described two possible ways for cells to know where they are in the body: Either they infer their location and adjust their behavior based on interactions with nearby cells, or they deduce their "positional identity" through the use of some type of coordinate system. The findings from the new Stanford study bolster the second possibility.........

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August 2, 2006, 11:29 PM CT

First Treatment For Drug-resistant HIV

Doctors have their first FDA-approved tool to treat drug-resistant HIV thanks to a new molecule created by a Purdue University researcher.

"There are a number of therapys for AIDS on the market, but none are able to combat drug resistance," said Arun Ghosh (pronounced A-rune GO-sh), a professor with a dual appointment in the departments of chemistry and medicinal chemistry and molecular pharmacology. "This is the first therapy that is effective against the growing number of drug-resistant strains of HIV, the virus that causes AIDS. The problem is widespread".

The FDA recently approved the pill-based treatment of Ghosh's molecule, TMC-114, for medical use. The molecule, also known as Darunavir (pronounced DA-rune-a-veer), is the forerunner in a series of molecules under development by Ghosh.

Earlier research shows that almost half of patients with the human immunodeficiency virus (HIV) who initially respond to therapy develop drug-resistant strains and stop responding to therapy within eight to 10 months, he said. An additional 20 percent to 40 percent of patients have drug-resistant strains when they are first diagnosed, suggesting these strains can be transmitted from one person to the next.

This year marks the 25th anniversary of the first reported U.S. cases of AIDS, a disease that claims the lives of more than 15,000 Americans each year, as per the Centers for Disease Control and Prevention. World Health Organization figures estimate more than 40 million people worldwide are infected with HIV.........

Posted by: Mark      Permalink         Source

August 2, 2006, 11:03 PM CT

Uterine Cancer May Yield Clues To Genetics

A new study suggests that women with endometrial cancer should be screened for inherited mutations that could lead to a high risk of several other cancers.

The study showed that 1.8 percent, or about one in 50, of newly diagnosed endometrial cancer patients have mutations for Lynch syndrome, an inherited condition also known as hereditary nonpolyposis colon cancer, or HNPCC.

People with Lynch syndrome mutations are at high risk for colon, endometrial, ovarian and gastric cancer. Endometrial, or uterine, cancer is the most common cancer in women with this condition.

The study, led by scientists at The Ohio State University Comprehensive Cancer Center - Arthur G. James Cancer Hospital and Richard J. Solove Research Institute (OSUCCC - James), is reported in the Aug. 1 issue of Cancer Research.

The study is the first to comprehensively screen a large number of women with uterine cancer for Lynch syndrome mutations, said Heather Hampel, a genetic counselor in the clinical cancer genetics program and first author of the study.

"It's important to identify women with one of these mutations because they have a very high risk for developing colon cancer, and they may not be aware of that risk," said Hampel. "Because this is hereditary, half of her siblings and children may also be at risk for the syndrome.........

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August 2, 2006, 9:25 PM CT

Basis For Perceptual Learning

The artist's trained eye can detect distinctions others can't; musicians pick up subtle changes in tone lost on the nonmusical. Brain scientists call these abilities perceptual learning.

Following up on an accidental finding, MIT scientists at the Picower Institute for Learning and Memory and his colleagues have uncovered a mechanism for this phenomenon. The study will appear in the Aug. 3 issue of Neuron.

The original idea was to look at how visual deprivation affects the brain. But before mice in the experiment were deprived of vision, scientists recorded baseline measurements by showing them a striped pattern on a video screen.

Unexpectedly, the scientists observed that eventhough no change showed up during the viewing session, as few as 12 hours later the mice were more visually "tuned" to the pattern they had seen. Over several sessions, the mice's brain responses to the stripes increased, with the biggest responses occurring to stripes the mice saw more often. The scientists dubbed this change "stimulus selective response potentiation" or SRP.

"The properties of SRP are strikingly similar to those described for some forms of human perceptual learning," said Mark Bear, Picower Professor of Neuroscience and co-author of the study. As a result, "understanding this type of perceptual learning is important because it can reveal mechanisms of implicit memory formation and might be exploited to promote rehabilitation after brain damage. Detailed knowledge of how practice changes brain chemistry is likely to suggest new pharmacological and behavioral therapies to facilitate these changes.........

Posted by: Daniel      Permalink         Source

August 1, 2006, 11:41 PM CT

Evolution At The Tips Of Chromosomes

In terms of their telomeres, mice are more complicated than humans. That's the finding from a recent Rockefeller University study, which shows that mice have two proteins working together to do the job of a single protein in human cells. The findings, published recently in Cell, suggest that the protein complex that protects chromosome ends may have evolved far more rapidly than previously believed.

Acting as caps on the ends of each chromosome, telomeres are composed of repetitive DNA and shelterin, a protective protein complex protects. Titia de Lange's lab has identified a number of of the components of shelterin and studies how its components work together to ensure that chromosome ends are not recognized as DNA breaks.

Prior work from the de Lange lab showed that TRF2, a shelterin protein that binds to the duplex part of the telomere, is crucial for telomere protection. Without TRF2, telomeres activate a DNA damage signal and are repaired by the same pathways that act on DNA breaks. TRF2 brings a second shelterin protein, POT1, to the telomeres. Because POT1 binds to single-stranded telomeric DNA present at the very end of the chromosomes, the de Lange lab asked how POT1 contributes to the protection of telomeres.

"We had previously removed TRF2 from mouse cells and seen a number of dramatic phenotypes," says de Lange, "all of the telomeres ligate together; there is a massive DNA damage response and the cells basically die. We argued that if the function of TRF2 was to bring POT1 to the DNA, then we should observe the same phenotype if we removed POT1".........

Posted by: Scott      Permalink         Source

August 1, 2006, 11:27 PM CT

Confusion, Not Stress

Even though they are trained in CPR, people hesitate to take action when an emergency unfolds in front of them. But the cause, a study has observed, is more likely to be confusion than stress.

A study conducted by several scientists surveyed 1,243 lay people trained in CPR (cardiopulmonary resuscitation) who took part in a clinical trial. Most of them said they experienced low stress levels when faced with responding to a person in medical distress. "Most lay responders did not view the experience as onerous, but there are people who had negative experiences," said Dr. David Feeny, a professor of Public Health Sciences at the University of Alberta, Edmonton, Canada, and one of the co-authors on the study. Also contributing to the study were scientists from the University of Pennsylvania, University of Pittsburgh, University of Washington, as well as medical workers and health centres.

The study was published recently in the journal Resuscitation.

Random cardiac arrest is a leading cause of death in North America and lay responder CPR rates remain low.

Respondents did indicate that practical issues such as crowd control and skill performance concerned them more than their emotions. Concerns included barriers to responding such as communication with confused and combative patients; skills such as accessing airways or taking accurate pulse checks; accessing the victim in awkward, dark or cramped areas; harnessing their own feelings of panic; and dealing with the characteristics of the victim, such as bleeding, jerking, vomiting, age and size.........

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August 1, 2006, 11:04 PM CT

Emphysema Patients Might Benefit From Surgery

The latest results from the landmark National Emphysema Treatment Trial (NETT) confirm and extend earlier findings that selected patients with advanced emphysema predominately in the upper area of the lung may benefit from surgery and the benefits are still apparent with two more years of follow-up. The newly published findings from the largest study of bilateral lung volume reduction surgery (LVRS) to treat severe emphysema also confirm that patients with upper-lobe emphysema and poor exercise capacity before surgery are more likely to have improved survival in comparison to similar patients treated with medical treatment without surgery. Surgery might also provide some symptom relief in patients with emphysema in the upper lung area but who had good exercise capacity previous to surgery; however, survival rates did not improve in this group.

NETT scientists describe the effects of LVRS after following 1218 patients for an average of 4.3 years, two years longer than the primary results reported in 2003. The earlier findings led to Medicare coverage of LVRS for patients meeting criteria based on the study results. NETT began in 1996 as a cooperative effort between the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health and the Centers for Medicare & Medicaid Services. Both are agencies of the U.S. Department of Health and Human Services.........

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August 1, 2006, 9:25 PM CT

How Kidneys Retain Proteins

New research may finally settle a decades-old debate about how the kidney keeps valuable blood proteins from harmfully slipping into the urine, a serious health symptom that often precedes kidney failure.

In genetically modified mice, researchers at Washington University School of Medicine in St. Louis captured images of a defective version of a kidney structure leaking a substance from the blood into the urine. The images suggest that the structure, known as the glomerular basement membrane (GBM), normally plays a key role in keeping blood proteins out of the urine.

The finding, published in the recent issue of the Journal of Clinical Investigation, will help doctors understand nephrotic syndrome, a condition with symptoms that include blood proteins in the urine. The syndrome can be triggered by a variety of genetic and environmental factors and leads to kidney failure over a varying time period.

"All the therapys we now use for nephrotic syndrome are either non-specific, meaning that we can't say for sure that they directly address the problem, or they are toxic," notes lead author George Jarad, M.D., a postdoctoral research scholar. "The first step to developing a specific therapy is to understand exactly what's happening. We have to know the details of the process before we can devise a remedy."........

Posted by: Mark      Permalink         Source

August 1, 2006, 7:06 AM CT

Study Frames Depression Treatment Puzzle

Reported in the August 2006 edition of the American Journal of Psychiatry, the study used electroencephalogram (EEG) measurements to demonstrate an association between eventual clinical outcome and regional changes in brain activity during a placebo lead-in phase previous to antidepressant therapy.

The findings suggest that factors such as patient beliefs and expectations, doctor-patient relationships, or therapy history help complete the therapy picture.

In this study, all subjects received blinded therapy with placebo for one week previous to receiving antidepressant medication. A "placebo lead-in" phase is usually used to familiarize patients with study procedures and to minimize the effect of any pre-existing therapy for depression. The placebo lead-in includes patient care, participation and therapy with placebo; the clinical impact is largely unknown.

This study is the first to assess the relationship between brain changes during the placebo lead-in phase and later clinical outcome of antidepressant therapy.

"Treatment results appear to be predicted, in part, by changes in brain activity found during placebo lead-in--previous to the actual use of antidepressant medication," said lead author Aimee M. Hunter, a research associate at the Semel Institute for Neuroscience and Human.........

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August 1, 2006, 7:02 AM CT

Reduce Prostate Cancer Growth Rate

UCLA scientists observed that altering the fatty acid ratio found in the typical Western diet to include more omega-3 fatty acids and decrease the amount of omega-6 fatty acids may reduce prostate cancer tumor growth rates and PSA levels.

Reported in the Aug. 1 issue of the journal Clinical Cancer Research, this initial animal-model study is one of the first to show the impact of diet on lowering an inflammatory response known to promote prostate cancer tumor progression and could lead to new therapy approaches.

The omega-6 fatty acids contained in corn, safflower oils and red meats are the predominant polyunsaturated fatty acids in the Western diet. The healthier marine omega-3 fatty acids are found in cold-water fish like salmon, tuna and sardines.

"Corn oil is the backbone of the American diet. We consume up to 20 times more omega-6 fatty acids in our diet in comparison to omega-3 acids," said principal investigator Dr. William Aronson, a professor in the department of urology at the David Geffen School of Medicine at UCLA and a researcher with UCLA's Jonsson Cancer Center. "This study strongly suggests that eating a healthier ratio of these two types of fatty acids may make a difference in reducing prostate cancer growth, but studies need to be conducted in humans before any clinical recommendations can be made".........

Posted by: Mark      Permalink         Source