FOCUS ON RECENT RESEARCH
This section includes brief accounts of selected Dartmouth research projects on biomedical and medical policy issues.
Smokers and drinkers who take betacarotene supplements in the hope of staving off cancer may actually be raising their risk, according to a recent study in the Journal of the National Cancer Institute. DMS epidemiologist John Baron found that in those who smoked or had more than one alcoholic drink a day, betacarotene doubled their risk of recurring adenomasbenign tumors that can lead to colorectal cancer. In nonsmokers or nondrinkers, beta-carotene was associated with a 44% decrease in risk compared to subjects in a control group receiving a placebo.
The little pill that could
Aspirin is proving to be an ever more powerful medication. The latest on the humble white pill is that it may help reduce infection. A study by DMS microbiologist Ambrose Cheung, M.D., showed that salicylic acidproduced when the body breaks down aspirindisrupts the ability of Staphylococcus aureus bacteria to adhere to host tissue. Staph infections are the leading cause of death in noncoronary ICUs. Aspirin does not cure infections, notes Cheung, but reduces the ability of bacteria to cause them. The work was published in the July 15 issue of the Journal of Clinical Investigation.
Battling fatal bulges
"Aneurysmsbulges in weakened artery walls that are almost always fatal when ruptured may be the most preventable common killer that doctors rarely warn about." So reported the Wall Street Journal this past June. Researchers at Dartmouth were already on the case, however. DMS surgeon Mark Fillinger, M.D., and colleagues at Dartmouth's Thayer School of Engineering, published a study in the Journal of Vascular Surgery on a noninvasive method of assessing the risk of an aneurysm's rupture by measuring stress on the vessel's wall using computerized analysis of CT scans. The new technique predicts rupture risk better than aneurysm diameter, the method used for more than 40 years.
A matter of some substance
Anne Brisson, Ph.D., an adjunct assistant professor of community and family medicine, will work during 2003-04 as a Fulbright Scholar on substance abuse issues in Kosova. She will help the Kosovar Ministry of Health develop a substance abuse strategic plan and will lecture on public policy at the University of Prishtina. "There is virtually no prevention or treatment system" there, she says. Before the 1999 Balkans war, substance abusers in Kosova traveled to Belgrade for treatment, "but now this is not an option," Brisson notes. Furthermore, Kosova "is on one of the main traf- ficking routes of heroin . . . with the result of cheap and pure heroin available." She expects the plan to emphasize developing treatment services and creating prevention materials for parents and drug-users.
These flies lay golden eggs
Dartmouth researchers have determined that the fruit fly Drosophila can be used to study why more cell-division mistakes occur as eggs become older. Biologist Sharon Bickel, Ph.D., reported in Current Biology that fruit flies are an excellent model organism to study how age affects meiosis, the specialized cell division involved in reproduction. In humans, meiotic errors can cause Down syndrome, the incidence of which increases with the mother's age. "Age-related meiotic defects are hard to study in humans, because it's difficult to examine how this process deteriorates in females over a span of 20 years," explains Bickel. "Because flies are easy to grow in the lab, it's possible to look at thousands of flies and determine how frequently mistakes during meiosis are occurring." Her team included M.D.-Ph.D. student Peter Burrage.
Gaze can faze, cause malaise
The direction of someone's gaze appears to affect how your brain interprets that person's emotions. A group of researchers in the Dartmouth psychology and brain science department found that whether or not someone is looking at you influences how your brainspecifically, your amygdala, which regulates emotions and detects threatsresponds to fear or anger. Published in Science, the study showed that people exhibit more amygdala activity when an angry person in a picture is looking away. But when people view expressions of fear, their amygdala is more active when there is eye contact. According to the paper, this study was the first one to show that gaze direction figures in the perception of facial expressions.
Not just for wrinkles any more
Dartmouth neurologists Thomas Ward, M.D., and Morris Levin, M.D., are exploring a new use for a potent neurotoxin best known as a treatment for wrinkles. Botulinum toxin, which prevents the release of several key neurotransmitters, "may have analgesic properties beyond merely muscle relaxation and paralysis," explains Ward. It thus holds potential for treating headaches, spasticity, and the abnormal muscle movements of Parkinson's and other diseases. Ward and Levin were involved in some of the original studies using botulinum toxin for headache, and they just received a two-year grant to teach physicians about the treatment of headache, including with botulinum toxin. The grant came through Thomas Jefferson University from the pharmaceutical company Allergan and was one of just six awarded nationwide.
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