November 19, 2006, 9:07 PM CT
Virtual Biopsies Of Internal Surfaces
OFDI image of the stented coronary artery of a pig
A new optical imaging technique, developed at the Wellman Center for Photomedicine at Massachusetts General Hospital (MGH), can provide three-dimensional microscopic views of the inner surfaces of blood vessels and gastrointestinal organs. In their report in the journal Nature Medicine, receiving early online release today, the MGH-Wellman scientists describe using optical frequency-domain imaging (OFDI) to visualize broad areas of the esophagus and coronary arteries of living pigs. The technique is an advance over optical coherence tomography (OCT) another noninvasive MGH-developed technology that details much smaller areas and could be useful for identifying premalignant lesions and dangerous deposits of plaque in the coronary arteries.
"For diagnosing early-stage disease, the physician has been basically looking for a needle in a haystack; so sampling only a few microscopic points of an organ, as we could with OCT, is clearly not sufficient," says Brett Bouma, PhD, of the MGH-Wellman Center, the report's senior author. "With OFDI, we can now perform microscopy throughout very large volumes of tissue without missing any locations."
While OCT can examine surfaces one point at a time, OFDI is able to look at over 1,000 points simultaneously by using a new type of laser developed at MGH-Wellman. Inside the fiberoptic catheter probe, a constantly rotating laser tip emits a light beam with an ever-changing wavelength. Measuring how each wavelength is reflected back, as the probe moves through the structure to be imaged, allows rapid acquisition of the data mandatory to create the detailed microscopic images.........
Posted by: Scott Permalink Source
November 16, 2006, 9:33 PM CT
Tooth Whiteners Do Not Cause Cancer
Common tooth whitening products, which have been used by millions of people, are found to be safe and do not increase the risk of oral cancer when used as directed. This exhaustive review of the literature, including numerous unpublished clinical studies involving over 4,000 human subjects, appeared in an article by Dr. Ian Monroe entitled, " Use of Hydrogen Peroxide-Based Tooth Whitening Products and it Relationship to Oral Cancer," published in Journal of Esthetic and Restorative Dentistry.
Clinical and laboratory data on tooth whitening products show no evidence for the development of oral cancer or of other effects that could be linked to increased oral cancer risk. Exposures to hydrogen peroxide, generally the effective ingredient in tooth whiteners, are too low and of too short of a duration (30-60 minutes) to cause any oral tissue changes that could enhance risks for oral cancer development. Concentrations of hydrogen peroxide rapidly decline to near undetectable levels commonly within 15 to 60 minutes.
Given the likely use of tooth whitening products by smokers, the review also sought to examine any possibility of increased oral cancer development due to combined exposure (i.e., hydrogen peroxide and carcinogenic agents that are present in cigarette smoke). A possible combined-effect, as seen in the increased likelihood of lung cancer development in smokers also exposed to asbestos, was found to be groundless with regards to bleaching and smoking and further illustrates the relative safety of tooth whitening products.........
Posted by: Janet Permalink Source
November 16, 2006, 9:23 PM CT
Edible Food Wrap Kills Deadly E. Coli
USDA chemist Tara McHugh displays edible food wraps designed to slow the spoilage of fresh fruits and vegetables. Similar wraps developed by McHugh also kill E. coli.
Scientists have improved upon an edible coating for fresh fruits and vegetables by enabling it to kill deadly E. coli bacteria while also providing a flavor-boost to food. Composed of apple puree and oregano oil, which acts as a natural antibacterial agent, the coating shows promise in laboratory studies of becoming a long-lasting, potent alternative to conventional produce washes, as per a team of researchers from the U.S. Department of Agriculture (USDA) and the University of Lleida in Spain.
The study comes on the heels of the recent deadly E. coli outbreak in spinach and amid growing concern by experts that some produce-cleaning techniques may not be effective in destroying E. coli. The study is scheduled for the Nov. 29 issue of the American Chemical Society's Journal of Agricultural and Food Chemistry.
"All produce-cleaning methods help to some degree, but our new coatings and films may provide a more concentrated, longer-lasting method for killing bacteria," says Research Leader Tara H. McHugh, Ph.D., a food chemist with the USDA's Agricultural Research Service in Albany, Calif. As the films are made of fruit or vegetable puree, they also provide added health benefits such as vitamins, minerals and antioxidants, she says.
Scientists have known about the antimicrobial activity of plant-derived essential oils for some time, but McHugh says that her group is the first to incorporate them into a fruit- or vegetable-based edible food wrap for the purpose of improving food safety. Three years ago, she and her associates developed a similar edible food wrap, but without the antimicrobial properties.........
Posted by: Mark Permalink Source
November 16, 2006, 9:17 PM CT
Personality Traits And Heart Disease
Frequent bouts of depression, anxiety, hostility and anger are known to increase a person's risk for developing coronary heart disease, but a combination of these "negative" personality traits may put people at particularly serious risk, as per a research studyby scientists at Duke University Medical Center.
"The risk of developing coronary heart disease due to a combination of negative personality traits in people has never before been explored," said the study's senior investigator, Edward C. Suarez, Ph.D., an associate professor of psychiatry. "Eventhough each of the negative traits significantly predicted heart disease, having the combination of these traits was the most powerful predictor of heart disease."
Similar patterns have been reported with three traditional risk factors of heart disease -- high blood pressure, elevated cholesterol levels and excessive weight -- where each factor independently increases risk but their presence together predicts a greater risk of future heart disease, Suarez said.
The findings are published in an early online edition of the November/December 2006 issue of the journal Psychosomatic Medicine.
The research was funded by the National Institutes of Health.
The team analyzed data on 2,105 military veterans who served in the Vietnam War and took part in the U.S. Air Force Health Study, in which scientists tracked the health of participants for 20 years. None of the men enrolled had heart disease when the study began.........
Posted by: Daniel Permalink Source
November 16, 2006, 7:09 PM CT
Dieting Vs Exercise
Those in their 50s and 60s who want to lose weight might consider heading to the cardio workout room instead of counting calories, suggests new research out this month.
Both those who dieted and those who exercised lost a significant amount of weight, as per findings from an NIH-funded study on whether a calorie-restriction diet can extend lifespan. However, while exercisers maintained their strength and muscle mass and increased aerobic capacity, those who dieted lost muscle mass, strength and aerobic capacity.
"Exercise-induced weight loss provides the additional benefit of improving physical performance capacity," says Edward Weiss, Ph.D., lead author and assistant professor of nutrition and dietetics at Saint Louis University's Doisy College of Health Sciences.
"If push comes to shove and somebody wants to know if they should diet or exercise to lose weight, I would suggest exercise, provided they are willing to put in the extra time and effort and not offset the gains they make by eating more".
Weiss is a part of a Washington University team of researchers who studied healthy 50- to 60-year olds whose body mass index was between 23 and 30, placing them at the high end of normal weight or overweight.
Of the 34 study participants, 18 dieted and 16 exercised to lose weight.........
Posted by: JoAnn Permalink Source
November 16, 2006, 4:45 AM CT
A Gene That Enhances Muscle Performance
Dartmouth researchers (l-r) Lee Witters, Christine Richardson, and Laura Barré. (Photo by Joseph Mehling '69
A team of researchers, led by researchers at Dartmouth Medical School and Dartmouth College, have identified and tested a gene that dramatically alters both muscle metabolism and performance. The scientists say that this finding could someday lead to therapy for muscle diseases, including helping the elderly who suffer from muscle deterioration and improving muscle performance in endurance athletes.
The scientists report that the enzyme called AMP-activated protein kinase (or AMPK) is directly involved in optimizing muscle activity. The team bred a mouse that genetically expressed AMPK in an activated state. Like a trained athlete, this mouse enjoyed increased capacity to exercise, manifested by its ability to run three times longer than a normal mouse before exhaustion. One especially striking feature of the finding was the accumulation of muscle glycogen, the stored form of carbohydrates, a condition that a number of athletes seek by "carbo-loading" before an event or game. The study appears in the Nov. 14 online issue of the American Journal of Physiology: Endocrinology and Metabolism.
"Our genetically altered mouse appears to have already been an exercise program," says Lee Witters, the Eugene W. Leonard 1921 Professor of Medicine and Biochemistry at Dartmouth Medical School and professor of biological sciences at Dartmouth College. "In other words, without a previous exercise regimen, the mouse developed a number of of the muscle features that would only be observed after a period of exercise training".........
Posted by: Scott Permalink Source
November 16, 2006, 4:41 AM CT
New Treatment Strategy For Thyroid Cancer
Dr. Lois Mulligan and PhD student Taranjit S. Gujral (Pathology and Molecular Medicine) used a three-dimensional model of a protein to chart its particular molecular mechanisms.
The actions of a mutated protein in cells associated with thyroid cancer have been uncovered by scientists at Queen's University. The discovery paves the way for the future development of drugs to more effectively target, treat and possibly even prevent both inherited and non-inherited thyroid cancers.
"We now know why this gene causes these tumours and can start looking at how best to target the mutant proteins so that the cells expressing them can be killed or stopped from growing," says Lois Mulligan, professor of pathology and molecular medicine with the Division of Cancer Biology and Genetics of the Queen's Cancer Research Institute. She is senior author of a study would be published November 15 in the journal Cancer Research.
Taranjit S. Gujral, a Ph D student in Queen's Department of Pathology and Molecular Medicine and lead author on the paper, developed three-dimensional models of the mutated RET protein implicated in a condition causing malignant thyroid tumours. The model allowed him to predict and compare the protein's molecular actions and to see that the protein was ten times more active than normal in cells linked to Multiple Endocrine Neoplasia 2B (MEN 2B) syndrome, an inherited cancer syndrome. Co-authors on the study include Vinay K. Singh and Zongchao Jia of Queen's Biochemistry Department.........
Posted by: Janet Permalink Source
November 16, 2006, 4:29 AM CT
Implantable Device System For BP Control
A device first implanted in the United States at the University of Rochester Medical Center as part of a clinical trial is showing a significant reduction in blood pressure in patients who suffer from severe high blood pressure and cannot control their condition with medications or changes in lifestyle.
Early findings were shared this week by University of Rochester Medical Center heart specialist John Bisognano, M.D., Ph.D., and Minneapolis-based device-maker CVRx at the American Heart Association 2006 Scientific Sessions in Chicago.
The ongoing study is assessing the safety and clinical efficacy of the RheosTM
Baroreflex High blood pressure TherapyTM
System, an implantable device for the therapy of high blood pressure in patients with drug-resistant hypertension, who have a systolic blood pressure of 160 mmHg or greater. The University of Rochester implanted the first device in the U.S. in March 2005, and performed a total of three of the initial 10 implantations.
High blood pressure affects about 65 million people in the U.S. It is estimated to cause one in every eight deaths worldwide. Each increase of 20 mmHg in systolic blood pressure or 10 mmHg in diastolic blood pressure above normal level is linked to a two hundred percent increase in death rates from stroke, coronary heart disease and other vascular causes. Approximately 25 percent of people with high blood pressure cannot control their high blood pressure, despite the use of multiple medications.........
Posted by: Daniel Permalink Source
November 15, 2006, 9:48 PM CT
NSAID and Liver Damage
Alpha-1-antitrypsin deficiency isn't a term that rolls right off the tongue. But people diagnosed with this genetic disorder learn its potential effects well. They know they shouldn't smoke or be around smokers because they are at increased risk for developing emphysema at a young age. In addition, some patients with alpha-1-antitrypsin (AT) deficiency can develop serious liver disease. But predicting which of them are at risk for liver disease is still not possible.
Now research performed at Washington University School of Medicine in St. Louis sheds light on the mechanisms that contribute to liver disease in alpha-1-AT deficiency patients. Using an experimental mouse model of the disorder, the scientists investigated the effects of a non-steroidal anti-inflammatory drug (NSAID) on liver injury. An estimated 15 to 20 million people in the United States take NSAIDs like ibuprofen and naproxen on a long-term basis.
The findings, reported in the recent issue of the journal Hepatology, show that the NSAID indomethacin (Indocin), administered at doses typically nontoxic to mice, significantly increased liver damage in the experimental mice.
The mice carried a mutated form of the human alpha-1-AT gene (called the alpha-1-ATZ gene), the most common form of the gene linked to the development of liver disease in people with alpha-1-AT deficiency. Greater expression of the mutant alpha-1-ATZ gene and increased amounts of alpha-1-ATZ protein in the liver accompanied the increase in liver injury in the experimental mice given the NSAID.........
Posted by: Sue Permalink Source
November 15, 2006, 9:39 PM CT
ADHD And Smoking
Are you easily forgetful, distracted, impulsive or fidgety? Do you find that smoking helps you alleviate these symptoms?.
Columbia University Medical Center scientists are investigating whether these most common symptoms of attention deficit hyperactivity disorders (ADHD) could be causing people to smoke. If that is the case, will therapy for ADHD combined with the standard therapy to help people quit smoking - the patch with counseling - increase the quit rates for smokers trying to quit?.
Lirio S. Covey, Ph.D., director of the Smoking Cessation Program at Columbia University Medical Center, is trying to find out.
Covey and her colleagues are recruiting smokers who have been diagnosed with ADHD or who may have symptoms of ADHD but have still not been diagnosed, to be part of a study that will help them quit smoking. Approximately 7-8 million adults in the U.S. have ADHD. Smoking is twice as common in this population as in the general population.
Research has shown that most smoking in the U.S. occurs among people who have psychiatric conditions, such as alcohol or drug abuse, major depression, anxiety and ADHD. One line of research has shown that smokers with these conditions "self-medicate" their symptoms with nicotine, the primary addictive substance in tobacco.........
Posted by: JoAnn Permalink Source