October 24, 2006, 8:55 PM CT
Genetic Variations Aspirin And Colon Cancer
Dartmouth scientists are among a team of doctors that have learned more about how people may or may not benefit from taking aspirin in the effort to curb colon cancer. Their study, which appears in the Oct. 18 issue of the Journal of the National Cancer Institute, finds that the beneficial effect of aspirin may be limited to individuals who have a specific genetic variation in their ODC gene.
"There is evidence that aspirin and related anti-inflammatory drugs can reduce the risk of colorectal adenomas [polyps] and cancer," says Elizabeth Barry, a research assistant professor of community and family medicine at Dartmouth Medical School, and one the authors of the study. "And with this study, we looked closer at the impact of aspirin in people who have a higher risk of developing colorectal adenomas, which lead to cancer, by examining their ODC genotype. So now we know that aspirin appears to work better in people who have this slight genetic variation, and this finding could potentially be clinically useful in the future by allowing physicians to predict which individuals are likely to benefit from aspirin use for colorectal cancer chemoprevention".
The scientists studied 973 subjects over three years as part of the Aspirin/Folate Polyp Prevention Study. In a randomized manner, some were given aspirin and some were given placebos. Almost half of the participants carried one or two copies of the ODC genetic variation. The study observed that there was no association between carrying the genetic variation and the occurrence or new adenomas, but the genotype did influence the effect of aspirin on adenoma development. Those with the ODC genetic variation were 23 percent less likely to develop new adenomas and 49 percent less likely to develop more advanced lesions, which also lead to cancer.........
Posted by: Sue Permalink Source
October 24, 2006, 6:08 PM CT
Electronic Chip Interacting With The Brain
Scientists at the University of Washington (UW) are working on an implantable electronic chip that may help establish new nerve connections in the part of the brain that controls movement. Their most recent study, would be reported in the Nov. 2, 2006, edition of Nature, showed such a device can induce brain changes in monkeys lasting more than a week. Strengthening of weak connections through this mechanism may have potential in the rehabilitation of patients with brain injuries, stroke, or paralysis.
The authors of study, titled "Long-Term Motor Cortex Plasticity Induced by an Electronic Neural Implant," were Dr. Andrew Jackson, senior research fellow in physiology and biophysics, Dr. Jaideep Mavoori, who recently earned a Ph.D. in electrical engineering from the UW, and Dr. Eberhard Fetz, professor of physiology and biophysics. For a number of years Fetz and colleagues have studied how the brains of monkeys control their limb muscles.
When awake, the brain continuously governs the body's voluntary movements. This is largely done through the activity of nerve cells in the part of the brain called the motor cortex. These nerve cells, or neurons, send signals down to the spinal cord to control the contraction of certain muscles, like those in the arms and legs.........
Posted by: Daniel Permalink Source
October 24, 2006, 6:03 PM CT
New Treatment For Obsessive-compulsive Disorders
In a paper published on-line in advance of publication in the Journal of Psychiatric Research, Sanjaya Saxena, M.D., Director of the Obsessive-Compulsive Disorders (OCD) Program at the University of California, San Diego (UCSD) School of Medicine, reports the surprising finding that the serotonin reuptake inhibitor (SRI) medication, paroxetine, is effective in treating patients with compulsive hoarding syndrome.
The study of 79 patients diagnosed with obsessive-compulsive disorder (OCD) 32 of them with compulsive hoarding syndrome suggests that further controlled trials of SRI medications for compulsive hoarding are now warranted.
Compulsive hoarding, which may affect up to 2 million people in the United States, is found in people with many diseases, including anorexia, schizophrenia, Alzheimer's disease and dementia. It is most often found in patients with OCD, though researchers are not yet sure if it is a subtype of OCD or a separate disorder.
In previous, retrospective studies looking at patients and data from past drug trials compulsive hoarding had been associated with poor response to SRI medications commonly used to treat OCD patients. However, no previous study had ever directly tested this widely held theory. Saxena's prospective study, comparing the hoarding and non-hoarding OCD patients, showed nearly identical responses to paroxetine (commonly known as Paxil.) The symptoms exhibited by patients in both groups improved significantly with treatment.........
Posted by: JoAnn Permalink Source
October 24, 2006, 5:54 PM CT
Predicting Risk for Recurrent Stroke
People who have just suffered their first ischemic stroke, a blood clot in the brain, often have elevated inflammatory biomarkers in their blood that indicate their likelihood of having another stroke or an increased risk of dying, as per Columbia University Medical Center scientists at NewYork-Presbyterian Hospital.
Reported in the Oct. 23 Archives of Internal Medicine, results of the new study indicate that these inflammatory markers are linked to long-term prognosis after a first stroke, and may help guide clinical care for people who have suffered a first stroke.
A biomarker called lipoprotein-associated phospholipase A2 (Lp-PLA2), which has been FDA-approved to predict the risk of first stroke, was found to be a strong predictor of recurrent stroke risk. Scientists also observed that elevated levels of another biomarker called high-sensitivity C-reactive protein (hs-CRP), a test usually used to predict risk of heart disease, was linked to more severe strokes and an increased risk of mortality.
"A better understanding of biomarkers for stroke risk may lead to the use of prophylactic therapys to reduce risk of people suffering debilitating strokes," said lead author Mitchell S. V. Elkind, M.D., M.S., associate professor of Neurology at Columbia University College of Physicians and Surgeons and neurologist at NewYork-Presbyterian. "For example, statins appear to lower these biomarker levels, so our next step may be to study the clinical benefit of prescribing statins to reduce the risk of stroke in people with elevated biomarkers, and also to treat people who have suffered a stroke so that they do not have another serious event".........
Posted by: Daniel Permalink Source
October 24, 2006, 5:47 PM CT
Virtual Colonoscopy More Expensive
Image courtesy of Mayo clinic
Wake Forest University Baptist Medical Center scientists have observed that "virtual" colonoscopy using a computer tomography (CT) scanner is considerably more expensive than the traditional procedure due to the detection of suspicious images outside of the colon.
"Virtual colonoscopy will certainly play a role in the future of colon cancer screening," said gastroenterologist Richard S. Bloomfeld, M.S., M.D., assistant professor of medicine at Wake Forest Baptist and a member of the research team. "It is important to understand the implications of findings outside the colon before we advocate wide-spread use of this technology".
Virtual colonoscopy, also known as CT-colonography (CTC), was developed at Wake Forest Baptist. It allows doctors to use Computerized axial tomography scanners to look at the colon to detect polyps (small growths in the colon that may become malignant if they are not removed) and cancers. Virtual reality software allows them to look inside the body without having to insert a long tube (conventional colonoscopy) into the colon or without having to fill the colon with liquid barium (barium enema).
Research performed at Wake Forest Baptist and elsewhere has shown that CTC is better able to see polyps than barium enemas and is nearly as accurate as conventional colonoscopy. Most patients report that CTC is more comfortable than either procedure.........
Posted by: Sue Permalink Source
October 22, 2006, 11:22 PM CT
Choosing Chemotherapy Using Genomics
Researchers at Duke University's Institute for Genome Sciences & Policy have developed a panel of genomic tests that analyzes the unique molecular traits of a malignant tumor and determines which chemotherapy will most aggressively attack that patient's cancer.
In experiments published in the November 2006 issue of the journal Nature Medicine, the scientists applied the genomic tests to cells derived from tumors of cancer patients. They observed that the tests were 80 percent accurate in predicting which drugs would be most effective in killing the tumor.
The Duke team plans to begin a clinical trial of the genomic tests in patients with breast cancer next year.
The new tests have the potential to save lives and reduce patients' exposure to the toxic side effects of chemotherapy, said Anil Potti, M.D., the study's lead investigator and an assistant professor of medicine in the Duke Institute for Genome Sciences & Policy. The tests are designed to help doctors select and initiate therapy with the best drug for a patient's tumor instead of trying various drugs in succession until the right one is found, Potti said.
"Over 400,000 patients in the United States are treated with chemotherapy each year, without a firm basis for which drug they receive," said Joseph Nevins, Ph.D., the study's senior investigator and a professor of genetics at the Duke Institute for Genome Sciences & Policy. "We believe these genomic tests have the potential to revolutionize cancer care by identifying the right drug for each individual patient".........
Posted by: Janet Permalink Source
October 22, 2006, 11:15 PM CT
Genes And Perception Of Pain
A new NIH-funded study shows that a specific gene variant in humans affects both sensitivity to short-term (acute) pain in healthy volunteers and the risk of developing chronic pain after one kind of back surgery. Blocking increased activity of this gene after nerve injury or inflammation in animals prevented development of chronic pain.
The gene in this study, GCH1, codes for an enzyme called GTP cyclohydrolase. The study suggests that inhibiting GTP cyclohydrolase activity might help to prevent or treat chronic pain, which affects as a number of as 50 million people in the United States. Doctors also may be able to screen people for the gene variant to predict their risk of chronic post-surgical pain before they undergo surgery. The results appear in the October 22, 2006, advance online publication of Nature Medicine.*.
"This is a completely new pathway that contributes to the development of pain," says Clifford J. Woolf, M.D., of Massachusetts General Hospital and Harvard Medical School in Boston, who led the research. "The study shows that we inherit the extent to which we feel pain, both under normal conditions and after damage to the nervous system." .
Dr. Woolf carried out the study in collaboration with Mitchell B. Max, M.D., of the National Institute of Dental and Craniofacial Research (NIDCR) in Bethesda, Maryland, and his colleagues at the National Institute on Alcoholism Abuse and Alcoholism (NIAAA) and elsewhere. Dr. Woolf's work was funded by the National Institute of Neurological Disorders and Stroke (NINDS). The research team also received funding from NIDCR, NIAAA, and other organizations.........
Posted by: Daniel Permalink Source
October 22, 2006, 10:57 PM CT
Excalia Combination Therapy To Treat Obesity
Therapeutics, Inc., a privately held clinical-stage neuroscience company developing novel strategic approaches to the therapy of obesity, today announced that ExcaliaTM
, a combination of two centrally-acting medications intended to provide and sustain clinically important weight loss, demonstrated significant weight loss in a six month, double-blind, phase IIa clinical study. The magnitude of weight reduction exceeded that seen with placebo. The findings showed that patients completing the blinded 24-week phase lost on average 9.2% of their weight from baseline using Excalia in comparison to an average of 0.4% weight loss from baseline for patients using placebo. The study results further demonstrate that weight loss continued through an additional 24 week open-label period achieving an average weight loss of 12% from baseline by 48 weeks. These top line phase IIa data for Excalia were presented at the annual meeting of the North American Association for the Study of Obesity (NAASO) in Boston.
"Excalia is designed to achieve an aggressive weight loss trajectory and then to delay the typical weight loss 'plateau' by offsetting one of the body's natural compensatory pathways. These phase II data suggest a level of efficacy that exceeded our expectations in relation to existing approaches," said Gary Tollefson, M.D., Ph.D., OREXIGEN president and CEO. "Excalia is designed to act on a specific reciprocally paired group of hypothalamic neurons that we believe will yield a clinically meaningful weight loss trajectory among significantly overweight individuals. We think that these positive data support our theoretical approach".........
Posted by: JoAnn Permalink Source
October 22, 2006, 8:47 PM CT
Portable 'lab on a chip'
This micropump allows high speed flows through microchannels with an input of only a few volts of electricity.
Testing soldiers to see if they have been exposed to biological or chemical weapons could soon be much faster and easier, thanks to MIT scientists who are helping to develop a tiny diagnostic device that could be carried into battle.
By tweaking the design of a tiny pump, scientists affiliated with MIT's Institute for Soldier Nanotechnologies have taken a major step towards making an existing miniature "lab on a chip" fully portable, so the tiny device can perform hundreds of chemical experiments in any setting.
"In the same way that miniaturization led to a revolution in computing, the idea is that miniature laboratories of fluid being pumped from one channel to another, with reactions going on here and there, can revolutionize biology and chemistry," says Martin Bazant, associate professor of applied mathematics and leader of the research team.
Within the lab on a chip, biological fluids such as blood are pumped through channels about 10 microns, or millionths of a meter, wide. (A red blood cell is about 8 microns in diameter.) Each channel has its own pumps, which direct the fluids to certain areas of the chip so they can be tested for the presence of specific molecules.
Until now, researchers have been limited to two approaches to designing labs on a chip, neither of which offer portability. The first is to mechanically force fluid through microchannels, but this requires bulky external plumbing and scales poorly with miniaturization.........
Posted by: Scott Permalink Source
October 22, 2006, 8:32 PM CT
Smoking Impedes Healing
Orthopaedic surgery scientists at Washington University School of Medicine in St. Louis have identified yet another reason not to smoke. Studying rotator cuff injury in rats, the research team found exposure to nicotine delays tendon-to-bone healing, suggesting this could cause failure of rotator cuff repair following surgery in human patients.
Smoking is implicated in a host of physical problems, from cardiovascular disease to lung disorders. A number of of us probably don't think about smoking's effects on orthopaedic conditions, but several studies have shown that nicotine interferes with healing of bone fractures and also inhibits bone fusion processes - a number of spine surgeons, for example, won't do certain operations on people who smoke because of the risk of failure. But little is known about the effects of cigarettes on tendon and ligament healing.
There also are some gaps in medical knowledge about the prevalence of rotator cuff injuries. The rotator cuff is a group of four muscles and their tendons in the shoulder that provide rotation, elevate the arm and stabilize the shoulder joint. Rotator cuff tears involve one or more of the tendons. The injuries are more common as people age and more common in the dominant arm. The true occurence rate of the injuries is hard to determine because between 5 percent and 40 percent of people who may have a torn rotator cuff have no accompanying shoulder pain.........
Posted by: Janet Permalink Source