November 18, 2008, 5:15 AM CT

Gene associated with epilepsy

A University of Iowa-led international research team has found a new gene linked to the brain disorder epilepsy. While the PRICKLE1 gene mutation was specific to a rare form of epilepsy, the study results could help lead to new ideas for overall epilepsy therapy.

The findings, which involved nearly two dozen institutions from six different countries, appear in the Nov. 7 issue of the American Journal of Human Genetics

In epilepsy, nerve cells in the brain signal abnormally and cause repeated seizures that can include strange sensations, severe muscle spasms and loss of consciousness. The seizures may not have lasting effects but can affect activities, such as limiting a person's ability to drive. Most seizures do not cause brain damage but some types of epilepsy lead to physical disabilities and cognitive problems. Medications can control symptoms, but there is no cure.

"The study results were surprising not only because the PRICKLE1 gene had never been linked to epilepsy but also because the gene was not linked to any other human disease," said the study's lead author Alex Bassuk, M.D., Ph.D., assistant professor of pediatrics at the University of Iowa Carver College of Medicine and a pediatric neurologist with University of Iowa Children's Hospital......... Posted by: Daniel      Read more         Source

November 18, 2008, 5:13 AM CT

Exercise increases brain growth factor

A new study confirms that exercise can reverse the age-related decline in the production of neural stem cells in the hippocampus of the mouse brain, and suggests that this happens because exercise restores a brain chemical which promotes the production and maturation of new stem cells.

Neural stem cells and progenitor cells differentiate into a variety of mature nerve cells which have different functions, a process called neurogenesis. There is evidence that when fewer new stem or progenitor cells are produced in the hippocampus, it can result in impairment of the learning and memory functions. The hippocampus plays an important role in memory and learning.

The study, "Exercise enhances the proliferation of neural stem cells and neurite growth and survival of neuronal progenitor cells in dentate gyrus of middle-aged mice," was carried out by Chih-Wei Wu, Ya-Ting Chang, Lung Yu, Hsiun-ing Chen, Chauying J. Jen, Shih-Ying Wu, Chen-Peng Lo, Yu-Min Kuo, all of the National Cheng Kung University Medical College in Taiwan. The study appears in the recent issue of the Journal of Applied Physiology, published by The American Physiological Society.

Rise in corticosterone or fall in nerve growth factor?

The scientists built on earlier studies that observed that the production of stem cells in the area of the hippocampus known as the dentate gyrus drops off dramatically by the time mice are middle age and that exercise can slow that trend. In the current study, the scientists wanted to track these changes in mice over time, and find out why they happen......... Posted by: Daniel      Read more         Source

November 17, 2008, 10:23 PM CT

Asthma may be over-diagnosed by up to 30 percent

A new research study suggests that asthma may be over-diagnosed by up to 30 per cent in Canadian adults. The study, led by Ottawa researcher Dr. Shawn Aaron, examined 496 people from eight Canadian cities who reported receiving a diagnosis of asthma from a physician. When the individuals were retested for asthma using the accepted clinical guidelines, it was observed that 30 per cent had no evidence of asthma. Two thirds of these individuals were able to safely stop taking asthma medications. The results are reported in the November 18, 2008 edition of the Canadian Medical Association Journal

"Our study suggests that there may be a substantial over-diagnosis of asthma in Canadian adults," said lead author Dr. Shawn Aaron, a Senior Scientist at the Ottawa Health Research Institute and Head of Respiratory Medicine at The Ottawa Hospital and the University of Ottawa. "This is a serious issue because asthma medications are expensive and they can have side effects. Also, an inappropriate diagnosis of asthma may obscure the true cause of a patient's symptoms".

The original goal of the study was to determine if obese people were more likely to be misdiagnosed with asthma, but the results showed that misdiagnosis was just as common in people of normal weight. The prevalence of asthma in Canada and America is five per cent overall, and 10 per cent for obese people. The overall prevalence has nearly doubled in the last 20 years......... Posted by: JoAnn      Read more         Source

November 17, 2008, 10:22 PM CT

Why only some former smokers develop lung cancer

Canadian scientists are trying to answer why some smokers develop lung cancer while others remain disease free, despite similar changes in lifestyle.

Results were presented at the American Association for Cancer Research's Seventh Annual International Conference on Frontiers in Cancer Prevention Research.

As per the Centers for Disease Control and Prevention, more people die from lung cancer than any other cancer type. In fact, as per 2004 data, more people died from lung cancer than breast, prostate and colon cancers combined.

Smoking is the biggest risk factor for developing lung cancer, even after quitting for long periods of time. "More than 50 percent of newly diagnosed patients with lung cancer are former smokers," said Emily A. Vucic, a graduate student at the British Columbia Cancer Research Centre, Vancouver, B.C. "Understanding why some former smokers develop lung cancer is clearly important to the development of early detection, prevention and therapy strategies".

The scientists studied how DNA methylation contributes to lung cancer development in former smokers. Methylation is an important event regulating gene expression during normal development. As we age and in cancer, proper patterns of DNA methylation become deregulated throwing off the tight control of gene activity that normally exists......... Posted by: Scott      Read more         Source

November 17, 2008, 10:18 PM CT

Antibiotics, your gut and you

We are always being told by marketers of healthy yogurts that the human gut contains a bustling community of different bacteria, both good and bad, and that this balance is vital to keeping you healthy. But if you target the disease-causing bacteria with medicine, what might be the collateral damage to their health-associated cousins that call the human body home?.

A new study by Les Dethlefsen et al, would be published this week in the online open-access journal PLoS Biology, looks into the changes that happen in the human gut when it is exposed to the widely used antibiotic, ciprofloxacin. Ciprofloxacin is prescribed for many conditions, including common afflictions such as urinary tract infections. It was previously believed to cause only modest harm to the abundant beneficial bacteria of the human body.

To investigate ciprofloxacin's effect on health-associated bacteria a team of researchers, led by Dr. David Relman of Stanford University, catalogued types of bacteria present in the faeces of volunteers who were undergoing a course of therapy of ciprofloxacin. The DNA-analysis technique, massively-parallel pyrosequencing, was central to their approach, which is outlined in a companion paper scheduled for publication in PLoS Genetics on Friday the 21st of November. With this technique, the scientists examined the diversity and abundance of bacteria present in human faeces, identifying over 5,600 different bacterial species and strains. The dramatically increased detection power of this approach allowed the team to track carefully the changes in the gut's bacterial community both during and after the course of therapy......... Posted by: Mark      Read more         Source

November 17, 2008, 10:16 PM CT

Psychological interventions associated with breast cancer survival

A new study finds that patients with breast cancer who participate in intervention sessions focusing on improving mood, coping effectively, and altering health behaviors live longer than patients who do not receive such psychological support. Reported in the December 15, 2008 issue of CANCER, a peer-evaluated journal of the American Cancer Society, the study indicates that reducing the stress that can accompany cancer diagnosis and therapy can have a significant impact on patients' survival.

Cancer patients undergo a significant amount of stress before, during, and after therapy. A number of scientists have theorized that providing mental health services in addition to cancer care may improve patients' health and even prolong their survival. But studies linking psychotherapy to improved survival have had inconsistent results. To test the hypothesis, Dr. Barbara L. Andersen and his colleagues at The Ohio State University conducted a randomized clinical trial with newly diagnosed patients with breast cancer that tested whether receiving a psychological intervention could reduce the negative effects of stress and ultimately change the course of a patient's disease. Prior papers have shown that the intervention significantly improved psychological, behavioral, and health outcomes and enhanced immunity......... Posted by: Janet      Read more         Source

November 17, 2008, 10:13 PM CT

Technology gives 3-D view of human coronary arteries

For the first time scientists are getting a detailed look at the interior of human coronary arteries, using an optical imaging technique developed at the Wellman Center for Photomedicine at Massachusetts General Hospital (MGH). In their report in the journal JACC: Cardiovascular Imaging, the research team describes how optical frequency-domain imaging (OFDI) gives three-dimensional, microscopic views of significant segments of patients' coronary arteries, visualizing areas of inflammation and plaque deposits.

"This is the first human demonstration of a technique that has the potential to change how heart specialists look at coronary arteries," says Gary Tearney, MD, PhD, of the MGH Pathology Department and the Wellman Center for Photomedicine at MGH, the study's lead author. "The wealth of information that we can now obtain will undoubtedly improve our ability to understand coronary artery disease and may allow heart specialists to diagnose and treat plaque before it leads to serious problems".

OFDI is an advance over optical coherence tomography (OCT), another imaging technology developed by the MGH investigators. While OCT examines tissues one point at a time, OFDI can look at over 1,000 points simultaneously using a device developed at MGH-Wellman. Inside a fiberoptic probe, a constantly rotating laser tip emits a light beam with an ever-changing wavelength. As the probe moves through the structure to be imaged, measuring how each wavelength is reflected back allows rapid acquisition of the data mandatory to create the detailed microscopic images. Besides providing three-dimensional images of an artery's microstructure in seconds, the increased speed also reduces signal interference from blood, which had plagued the first-generation technology. In 2006 members of the MGH-Wellman team reported the successful use of OFDI to image the esophagus and coronary arteries of pigs......... Posted by: Daniel      Read more         Source

November 14, 2008, 9:42 PM CT

When You Look at a Face, You Look Nose First

While general wisdom says that you look at the eyes first in order to recognize a face, UC San Diego computer researchers now report that you look at the nose first.

The nose may be the where the information about the face is balanced in all directions, or the optimal viewing position for face recognition, the scientists from UC San Diego's Jacobs School of Engineering propose in a paper recently reported in the journal Psychological Science.

The scientists showed that people first look just to the left of the center of the nose and then to the center of the nose when trying to determine if a face is one they have seen recently. These two visual "fixations" near the center of the nose are all you need in order to determine if a face is one that you have seen just a few minutes before. Looking at a third spot on the face does not improve face recognition, the cognitive researchers found.

Understanding how the human brain recognizes faces may help cognitive researchers create more realistic models of the brain-models that could be used as tools to train or otherwise assist people with brain lesions or cognitive challenges, explained Janet Hsiao, the first author on the Psychological Science paper and a postdoctoral researcher in the computer science department at UC San Diego......... Posted by: Daniel      Read more         Source

November 14, 2008, 9:02 PM CT

How the brain takes care of things

Thanks to our ability to learn and to remember, we can perform tasks that other living things can not even dream of. However, we are only just beginning to get the gist of what really goes on in the brain when it learns or forgets something. What we do know is that changes in the contacts between nerve cells play an important role. But can these structural changes account for that well-known phenomenon that it is much easier to re-learn something that was forgotten than to learn something completely new? Researchers at the Max Planck Institute of Neurobiology have been able to show that new cell contacts established during a learning process stay put, even when they are no longer required. The reactivation of this temporarily inactivated "stock of contacts" enables a faster learning of things forgotten. (Nature, November 12, 2008).

While an insect still flings itself against the window-pane after dozens of unsuccessful attempts to gain its freedom, our brain is able to learn very complex associations and sequences of movement. This not only helps us to avoid accidents like walking into glass doors, but also enables us to acquire such diverse skills as riding a bicycle, skiing, speaking different languages or playing an instrument. Eventhough a young brain learns more easily, we retain our ability to learn up to an advanced age. For a long time, researchers have been trying to ascertain exactly what happens in the brain while we learn or forget......... Posted by: Daniel      Read more         Source

November 14, 2008, 8:23 PM CT

Mending broken hearts with tissue engineering

Broken hearts could one day be mended using a novel scaffold developed by MIT scientists and his colleagues.

The idea is that living heart cells or stem cells seeded onto such a scaffold would develop into a patch of cardiac tissue that could be used to treat congenital heart defects, or aid the recovery of tissue damaged by a heart attack. The biodegradable scaffold would be gradually absorbed into the body, leaving behind new tissue.

The accordion-like honeycomb scaffold, published in the Nov. 2 online edition of Nature Materials, is the first to be explicitly designed to match the structural and mechanical properties of native heart tissue. As a result, it has several advantages over prior cardiac tissue engineering scaffolds.

Further, the MIT team's general approach has applications to other types of engineered tissues. "In the long term we'd like to have a whole library of scaffolds for different tissues in need of repair," said Lisa E. Freed, corresponding author of the paper and a principal research scientist in the Harvard-MIT Division of Health Sciences and Technology (HST). Each scaffold could be tailor-made with specific structural and mechanical properties. "We're already on the way to a few other examples," Freed said.

With respect to the current work, "prior scaffolds did not necessarily possess structural or mechanical properties consistent with the native myocardial [heart muscle] structure," said George C. Engelmayr Jr., lead author of the paper and an HST postdoctoral fellow. Heart muscle, he explained, is "directionally dependent" -- meaning its cells are aligned in specific directions......... Posted by: Daniel      Read more         Source