02.20.08
Posted in Biology at the University of Virginia, Infectious Disease, Jacob Canon, Parasites, The Oscar Show, UVa College of Arts & Sciences, Uncategorized, University of Virginia, biology, biomedical engineering, immune, physical health at 12:10 pm by Jacob Canon
In today’s show, adapted from an article published this month on the Oscar Web site written by Mary Jane Gore, we look at the research of Dr. William Petri, chief of the UVa Division of Infectious Diseases and International Health, and his study of a voracious parasite that is said to kill nearly 100, 000 people each year.
Pathogens & Parasites [5:40m]:
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If you have ever contemplated working as a biological researcher then you would probably have considered these questions: what happens when a cell’s life ends? And, what are the mechanisms that control decay?
Contemplating just these types questions during a recent study, a UVa-led research team, directed by Dr. William Petri, chief of the UVa Division of Infectious Diseases and International Health, made discoveries which are helping to stop one of the world’s most voracious parasites.
The team included Douglas Boettner (now completing postdoctoral work in Miami), U.Va. graduate students Alicia S. Linford and Sarah Buss and faculty colleagues Dr. Eric Houpt and Dr. Nicholas Sherman of UVa and Dr. Christopher D. Huston of the University of Vermont.
Their work revolved around the hypothesis that identifying molecules involved in the corpse ingestion would provide insight into how the amoebae cause colitis in children. These amoebae, properly known as entamoeba histolytica, cause colitis, or inflammation of the colon. They do this by attacking and killing human immune cells in mere seconds. It then it hides the evidence by eating the cells’ corpses.
In doing so, per data from Dr. Gerald Mandell of U.Va. Infectious Diseases and editor of Mandell, Douglas and Bennett’s Principles and Practice of Infectious Diseases, 6th edition, this murderous marauder “on a global basis, affects approximately 50 million people each year, causing diarrhea, malnutrition and nearly 100,000 deaths.
Dr. Petri’s team identified a particular protein on the surface of the ameba called a kinase, PATMK. Their work, published in the Jan. 18 issue of PLoS Pathogens, a peer-reviewed, open-access journal from the Public Library of Science, outlined a special technique called RNA interference, which inhibits the actions of this kinase, thus preventing the amoebae from eating the dead cells.
Dr. Petri, said, “by blocking this kinase, we have for the first time prevented the ameba from colonizing and invading the gut. This means that we are a step closer to preventing this disease, which wreaks havoc among children worldwide.”
The first author of the paper, Douglas Boettner said, “infection and further invasion into the gut require the clearance of dead cells in order to prevent immune recognition of the damaged tissue. PATMK is the first individual member of a large family of proteins to be assigned a function related to the clearance of dying tissue during pathogenesis.”
Boettner added, “this protein may be a pivotal vaccination target because these preliminary studies show that alterations in PATMK function reduced progression of amoebiasis in mice, a vaccine that ultimately would prevent this ameba from clearing the damaged host may draw in helpful immune cells, and thus help to clear this infection.”
Their work has shown how infection depends upon the ameba’s consumption of dead cells. By identifying the molecule that controls this consumption, scientists are one step closer to the ultimate goal of preventing the diseases caused by this parasite.
You’ve been listening to the Oscar Show, I’m Jacob Canon. Join us next week when our topic will be the research of Adrienne Felt, a fourth-year computer science major in the School of Engineering and Applied Science, concerning privacy issues surrounding social networking platforms such as Facebook.
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11.22.07
Posted in Jacob Canon, James Coan, MRI, Psychology, Relationships, The Oscar Show, University of Virginia, anxiety, brain, emotions, environmental conditions, happiness, hypothalamus, immune, nervous system, neurobiology, neurophysiology, physical health, physiology, sensory inputs, stress at 3:46 pm by Jacob Canon
How did you react the last time you had a fight with that significant someone in your life? With couples, the woman might apologize, or the man might make a joke or express understanding. By doing this, they subtly and briefly lighten the tension as they work their way through a disagreement.
Psychology Professor James Coan discovered a long time ago that by doing this, even when couples fight, they take care of each other. This interplay was significant when Coan designed a study exploring what happens in people’s brains when they behave emotionally or observe other people’s emotions. Coan said, “what we are learning is our emotions are more heavily involved in our day-to-day physical health than we previously thought.
How we deal with our relationships is closely tied to how long we live, how frequently we go to the doctor, how rapidly we recover from injury, how happy we tend to be in our lives.” With his colleagues, Hillary Schaefer and Richard J. Davidson from the University of Wisconsin, Coan sought to demonstrate the neurobiological basis of emotional expression and regulatory processes.
In the study, they used MRI technology to view these responses at the level of glucose metabolism and blood oxygenation in the brain. Because of the importance of emotional connectedness to the study, 16 happily married, heterosexual couples were recruited as test subjects. Wives were placed in the scanner so brain activity could be recorded as each was exposed to the anxiety-producing possibility of an electric shock to the ankle.
Researchers wanted to see what effect different types of emotional support would have in areas of the brain related to the body’s normal fight-or-flight stress response. Readings were taken when the woman was alone in facing this challenge, When a stranger, a male, was present to support her And when her husband offered support. Coan stated, “the scanning environment is pretty hostile to looking at interactions between people.” The MRI machine surrounds the subject’s body and restricts movement. The women weren’t even able to see the support person during the scanning process.
Having the man offer his hand for the woman to hold was about the only intervention possible in this setting. Not surprisingly, the results show there was a healthy reduction in the stress response when test subjects were supported. Stimulation in the regions of the brain that regulate physiological arousal and coordinate large muscles and joints was significantly decreased, no matter who was holding the woman’s hand. However, when it was her husband’s hand she was holding, the response was significantly greater.
Coan said, “When you’re holding a spouse’s hand, you get down-regulation in all of those same systems. But all the other systems that have to do with the conscious regulation of your emotions — having to pay attention to what’s happening with your body and having to become more vigilant for future dangers — all of these other systems come down as well. Your brain doesn’t work as hard when it’s your spouse. What surprised Coan and his colleagues most was the relaxation response demonstrated by what they called “super couples.” In those couples with exceptionally high-quality relationships, “Hand-holding had a significantly greater effect on soothing their brains.”
Tests showed differences involving two structures that were not affected at all in other test subjects. They observed evidence of reduced release of stress hormones by the hypothalamus. These hormones are responsible for inhibiting immune response and other activities that have critical implications for health and well-being.
Of greater interest was the reduction of activity in the right anterior insula. This brain structure modulates the amount of pain stimulus one experiences subjectively. Reduction of activity in this area means test subjects actually felt less pain when they held their husband’s hand.
So it can be said, having someone you love hold your hand really can take the hurt away.
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