Antibiotic treatment effective for common gastrointestinal disorder
A ground-breaking antibiotic therapy is the first potential drug treatment to provide irritable bowel syndrome patients with long-lasting relief of their symptoms even after they stop taking the medication, according to a study published in the Jan. 6 issue of the New England Journal of Medicine.
Unlike other traditional therapies for Irritable Bowel Syndrome, patients in these large studies reported relief of their symptoms for up to 10 weeks after completing treatment with rifaximin, says Dr. William Chey, professor in the Department of Internal Medicine.
Rifaximin is a minimally absorbed antibiotic that stays in the gut. Specifically, patients reported improvement in overall IBS symptoms, relief from bloating, less abdominal pain and improved stool consistency for up to 10 weeks, says Chey, one of the researchers on the study and director of the Michigan Bowel Control Program.
While the concept of bacteria playing a key role in this condition was controversial when first introduced a decade ago, this research confirms that bacteria in the gut, also known as the “gut microbiome,” plays a role in the symptoms of IBS, a chronic condition affecting an estimated 30 million people in the United States. The therapy was developed at Cedars-Sinai Medical Center.
These findings show that targeted antibiotics provide safe and effective long-lasting relief for this condition, says the study’s lead author, Dr. Mark Pimentel, GI Motility Program director and principal investigator of the clinical trials at Cedars-Sinai.
“This represents a big change in the way we think about and treat IBS,” says Chey, adding that IBS often does not respond well to treatments currently available like dietary changes or fiber supplements alone.
— Mary Masson, UMHS Public Relations
Researchers take a step toward more efficient energy conversion
The right material wrapped around your car’s exhaust system could one day scavenge heat that otherwise would be wasted, turning it into energy to warm the cabin or recharge the battery.
Engineers and physicists at U-M have taken a step toward improving the efficiency of a promising candidate for this burgeoning power source.
The researchers studied skutterudites, a class of mechanically strong thermoelectric materials that, when combined with certain elements such as the metal barium, has the right mix of properties to effectively make this energy conversion: The material conducts electricity well, and conducts heat poorly. The researchers identified certain configurations of the atoms in the compound that drastically increase the materials’ efficiency.
Their work is published in the current edition of Physical Review Letters.
“We knew that skutterudites are promising materials. But we did not know what features we could manipulate to maximize the conversion of heat into electricity,” says Ctirad Uher, professor in the Department of Physics. “In this paper, we propose that certain configurations of the filler element barium will be very effective in lowering the materials’ thermal conductivity and thus increasing their conversion efficiency.
“This is an important advancement in the sense that it provides guidance for the experimentalists to focus as they try to synthesize highly efficient thermoelectric materials.”
Today’s state-of-the-art thermoelectric materials are only 5 percent efficient. Skutterudites, and this new knowledge about how best to arrange their atoms, could help improve their performance to 15- or 20-percent, at which point they become useful in many practical applications, says Massoud Kaviany, professor in the Department of Mechanical Engineering.
Car companies are extremely interested in this technology, Uher says. The ideal environments for these materials are spots where large differences in temperatures exist. One such place is the pipe system of a car between the motor and the catalytic converter.
Also contributing to the research is Anton van der Ven, an assistant professor in the Department of Materials Science and Engineering.
— Nicole Casal Moore, News Service
The universe’s most massive stars can form in near isolation, new study finds
New observations by U-M astronomers add weight to the theory that the most massive stars in the universe could form essentially anywhere, including in near isolation; they don’t need a large stellar cluster nursery.
This is the most detailed observational study to date of massive stars that appear (from the ground) to be alone. The scientists used the Hubble Space Telescope to zoom in on eight of these giants, which range from 20 to 150 times as massive as the sun. The stars they looked at are in the Small Magellanic Cloud, a dwarf galaxy that’s one of the Milky Way’s nearest neighbors.
Their results, published in the Dec. 20 edition of the Astrophysical Journal, show that five of the stars had no neighbors large enough for Hubble to discern. The remaining three appeared to be in tiny clusters of 10 or fewer stars.
There is currently a big debate about the origins of these giant stars, say doctoral student Joel Lamb and associate professor Sally Oey.
One theory is that the mass of a star depends on the size of the cluster in which it is born, and only a large star cluster could provide a dense enough source of gas and dust to bring about one of these massive stars. The opposing theory, and the one that this research supports, is that these monstrous stars can and do form more randomly across the universe — including in isolation and in very small clusters.
The researchers acknowledge the possibility that all of the stars they studied might not still be located in the neighborhood they were born in. Two of the stars they examined are known to be runaways that have been kicked out of their birth clusters. But in several cases, the astronomers found wisps of leftover gas nearby, strengthening the possibility that the stars are still in the isolated places where they formed.
— Nicole Casal Moore, News Service
Individuals who are victimized — especially in childhood — likely to abuse alcohol, drugs
A new study finds strong associations between victims’ experiences — such as unwanted sexual activity, neglect and physical violence — and substance use disorders.
Substance use disorders and victimization experiences were more prevalent for gays, lesbians and bisexuals than heterosexuals, according to researchers from U-M, University of Illinois at Chicago and University of North Dakota.
Lesbian and bisexual women were more than twice as likely as heterosexual women to report any victimization experiences, the findings show. Gay men also had high prevalence rates of victimization with about half of them reporting such experiences in their lifetimes.
Men and women who reported two or more victimization experiences had higher odds of alcohol and other drug dependence, indicating a cumulative effect of multiple experiences, the researchers say.
“Programs and interventions must go beyond educating youth about the risks of substance use to help youth also recognize and cope with the stressors of childhood physical and sexual abuse, relationship violence and other forms of victimization, especially among sexual minority youth,” said Sean Esteban McCabe, a research associate professor at the Substance Abuse Research Center and Institute for Research on Women and Gender.
Additional U-M authors are Brady West, a doctoral student in the Michigan Program in Survey Methodology at the Institute for Social Research, and Carol Boyd, director of the Institute for Research on Women and Gender.
The findings appear in the December issue of Addiction.
— Jared Wadley, News Service
Study: Kids frequently exposed to imaging procedures that use radiation
The rapid growth in use of medical diagnostic imaging, such as CT scans, has led to widespread concern about radiation exposure in adults and the potential for future cancer risk in patients undergoing these tests.
A new study led by U-M researchers now shows that kids also frequently receive these types of imaging procedures during their routine clinical care, and highlights the importance of initiatives to ensure that those tests being performed are necessary and use the lowest possible doses of radiation.
“Our findings indicate that more awareness about the frequent use of these tests may be needed among care providers, hospitals and parents,” says Dr. Adam Dorfman, clinical assistant professor of pediatrics and communicable diseases and of radiology at the Medical School. “Imaging tests are a critical component of good medical care, but the high number of tests raises questions about whether we are being judicious in our use of the technology.”
The results of this study were published online Jan. 3 in the Archives of Pediatrics and Adolescent Medicine.
“What we’ve tried to do is raise awareness of the issue and start a national dialogue by identifying the overall scope of the problem,” Dorfman says. “The next step is to better understand when these tests really add value to the care of a child and when they do not.”
Among the tests that the investigators considered, CT scans are the most important from the standpoint of radiation exposure. Nearly 8 percent of the children in this study received a CT scan in the three-year study period, with 3.5 percent of the children receiving more than one. Understanding patterns of utilization of these tests in children is important because children and infants are more susceptible than adults to the risks of radiation exposure, such as future cancers.
Additional U-M authors are Emmanuel Christodoulou, Dr. Ramon Sanchez, and Dr. Brahmajee Nallamothu, all of the Medical School.
— Margarita Wagerson, UMHS Public Relations
