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Methamphetamine study suggests increased risk for HIV transmission

WINSTON-SALEM, N.C. – New findings that one in 20 North Carolina men who have sex with men (MSM) reported using crystal methamphetamine during the previous month suggests increased risk for spreading HIV and other sexually transmitted diseases (STD), according to researchers from Wake Forest University School of Medicine and colleagues.

The rate of methamphetamine use among 1,189 MSM was 30 times higher than levels reported in the general U.S. population over the same period. Methampehtamine, or “meth,” is a highly addictive stimulant that has been found to impair judgment, decrease inhibition, increase impulsivity and enhance sexual sensitivity – which can all increase the potential for transmitting HIV.

The study’s authors found that participants who reported using methamphetamines were more likely to report inconsistent condom use during anal sex within the past three months, a history of STD infection, being HIV-positive and using medications designed to treat erectile dysfunction.

“Until now, there has been little data on meth use in the Southeast,” said lead author Scott D. Rhodes, Ph.D. M.P.H., associate professor in the Department of Social Sciences and Health Policy. “Our findings, including that meth users were more likely to be HIV-positive, suggest that prevention, intervention and treatment efforts are urgently needed.”

Rhodes noted that some of the men reported having sex with both men and women, which means the risk of HIV extends to both sexes.

The study’s results will be published on Aug. 20 in AIDS Patient Care and STDs, a leading AIDS journal that provides the latest research for clinicians and researchers. It is among the first to document meth use among MSM in the South, which carries a disproportionate HIV, AIDS, and STD burden, with 46 percent of newly identified cases.

“The findings underscore the need for further research and intervention,” said Rhodes. “The HIV/AIDS epidemic is clearly not over. We must develop innovative intervention approaches designed to reach communities at highest risk. Men who have sex with men, whether or not they identify themselves as gay, who use drugs like methamphetamines are clearly at higher risk. Yet currently nothing is being done in the Southeast.”

Participants were recruited in 2005 in five gay bars and in five geographically defined internet chat rooms in central North Carolina (primarily rural/suburban areas) and were asked to complete a brief assessment of drug use and other risk behaviors. Of the 1,189 MSM, two-thirds self-identified as black or other minorities, and 25 percent as bisexual. The mean age was 29 years.

In addition to being more inclined to risky sexual behaviors, the study participants who said they used methamphetamines were also more likely to report having higher education and health insurance coverage.

“Because users of methamphetamines were more likely to have higher educational levels and report having health insurance, we must change the way we think about meth users and develop sophisticated prevention strategies that are appropriate for these types of users,” noted Rhodes. “In addition, the link between meth use and the use of drugs for sexual dysfunction among a young population deserves attention. Meth use in combination with one of these medications may be having an even more profound impact on the HIV and STD disease epidemics in the South.”

Rhodes is also affiliated with the Maya Angelou Research Center on Minority Health at Wake Forest. In 2006, Rhodes won the New Investigator Award in Clinical Sciences at Wake Forest.

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The study’s co-authors include Emily Knipper and Aimee M. Wilkin, M.D., M.P.H., both with Wake Forest, Kenneth C. Hergenrather, Ph.D., M.S.Ed., M.R.C., of George Washington University, Leland J. Yee, Ph.D., M.P.H., of the University of Pittsburgh, and Morrow R. Omli, M.A.Ed., of the University of Florida.

Media Contacts: Karen Richardson, krchrdsn@wfubmc.edu, or Shannon Koontz, shkoontz@wfubmc.edu, 336-716-4587.

Wake Forest University Baptist Medical Center is an academic health system comprised of North Carolina Baptist Hospital and Wake Forest University Health Sciences, which operates the university’s School of Medicine. U.S. News & World Report ranks Wake Forest University School of Medicine 18th in family medicine, 20th in geriatrics, 25th in primary care and 41st in research among the nation’s medical schools. It ranks 35th in research funding by the National Institutes of Health. Almost 150 members of the medical school faculty are listed in Best Doctors in America.

Contact: Karen Richardson
krchrdsn@wfubmc.edu
336-716-4453
Wake Forest University Baptist Medical Center

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August 27, 2007 Posted by | Drug Abuse, Global Health Vision, Global News, HIV, University of Florida, University of Pittsburgh, Wake Forest University Baptist Medical Center, Washington DC, Washington DC City Feed, Washington University | Leave a comment

Nerves controlling muscles are best repaired with similar nerves

Contact: Beth Miller
millerbe@wustl.edu
314-286-0119
Washington University School of Medicine

When repairing severed or damaged motor nerves with a donor nerve graft, surgeons have traditionally used a sensory nerve from another area of the patient’s body. However, these patients often do not fully regain function in the injured area.

But now a team of surgeons at Washington University School of Medicine in St. Louis and Barnes-Jewish Hospital has found that repairing a motor nerve in rats with an intact motor nerve yields better results than using a sensory nerve. The research appeared in the March issue of the journal Microsurgery.

Motor nerves control movement in the muscles, while sensory nerves receive sensory stimuli, such as pain. A significant difference between the two types of nerves is that motor nerves have much larger axons, the thread-like extensions of the nerve cell that carry nerve impulses throughout the body.

The researchers, led by Gregory H. Borschel, M.D., a plastic and reconstructive surgeon at the School of Medicine and senior author of the paper, defines the question of this work as seeking to determine why motor nerves were regenerating more successfully than sensory nerves. Was it because of the nerve’s own structure, or architecture, or because supporting cells such as Schwann cells were boosting the regeneration”

To find an answer, the researchers broke down the nerve architecture by chopping up motor, sensory and mixed nerves. They divided the minced nerves into groups by type, inserted the mush into tiny silicone tubes and encouraged severed motor nerves to regenerate through the mixtures in the tubes.

The researchers found that disrupting the nerve’s architecture by mincing it abolished the benefit of repairing a motor nerve with an intact motor nerve. “It turned out there was no difference in regeneration using motor versus sensory nerves through the chopped-nerve tissue,” Borschel said.

Several factors contributed to the results, he said. “We know that the axons, or nerve fibers, in the motor nerves are bigger, while the sensory nerve fibers are smaller,” he said. “When the nerves are trying to regenerate using a motor nerve as a graft, it’s easier for them to use the larger axons of another motor nerve, although the reason why is not clear.”

The results could eventually translate into improved treatment for humans who have nerve damage from industrial, recreational or auto accidents.

“The research data is very compelling,” Borschel said. “The evidence presented through this study could represent a paradigm shift from what we currently do in the operating room. The current standard of treatment for fixing a gap in a motor nerve is to use a sensory nerve, but we believe that if you use a motor nerve instead of a sensory nerve, then the outcome would be better.”

The surgeons in the Division of Plastic and Reconstructive Surgery have begun using motor nerves grafts in limited patient cases with good results, Borschel said, but to clearly demonstrate the difference between motor nerve grafting and sensory nerve grafting in humans, much more study is needed.

One obstacle to the use of more motor nerve grafts is that the human body has a limited number of expendable motor nerves. Currently, surgeons are able to use the nerve from the gracilis muscle along the inner thigh or the latissimus dorsi along the side of the torso.

“This study, in conjunction with other related work from our laboratory, will likely result in a shift away from the use of traditional sensory nerve grafts to the much more permissive motor nerve grafts for reconstruction of injury,” said Susan E. Mackinnon, M.D., the Sydney M., Jr. and Robert H. Shoenberg Professor and Head of the Division of Plastic and Reconstructive Surgery at the School of Medicine.

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Lloyd BM, Luginbuhl RD, Brenner MJ, Rocque BG, Tung TH, Myckatyn TM, Hunter DA, Mackinnon SE, Borschel GH. Use of motor nerve material in peripheral nerve repair with conduits. Microsurgery, Volume 27, Issue 2.

Funding from the National Institutes of Health supported this research.

Washington University School of Medicine’s full-time and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children’s hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked fourth in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children’s hospitals, the School of Medicine is linked to BJC HealthCare.

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May 11, 2007 Posted by | Global, Global Health Vision, Global News, Washington University | Leave a comment

Study finds regions of DNA that appear linked to autistic spectrum disorders

Contact: Jim Dryden
jdryden@wustl.edu
314-286-0110
Washington University School of Medicine

Using an innovative statistical approach, a research team from Washington University School of Medicine in St. Louis and the University of California, Los Angeles, has identified two regions of DNA linked to autism. They found the suspicious DNA with a much smaller sample of people than has been used traditionally in searches for autism genes.

Autism — a disorder that involves social deficits, language problems and repetitive, stereotyped behaviors — affects around one in 1,000 children. And the combined incidence of autism spectrum disorders, which include Asperger syndrome and pervasive developmental disorder, brings the total number of affected children to one in every 150 births. Boys are affected three to four times more often than girls.

There’s clearly a genetic component to autism, according to John N. Constantino, M.D., associate professor of psychiatry and pediatrics at Washington University School of Medicine and a co-principal investigator on this latest study. If one child in a family is autistic, there’s a 10 percent chance a sibling also will have autism. Past research has isolated a few regions of DNA linked to autism, but very few of those studies have been replicated, so no specific autism genes have yet been identified.

“Those older studies used what’s called an ‘affected sib pair’ design that looks for genetic markers in siblings with autism,” says Constantino. “That approach has worked well for single-gene disorders, but autism is a complex disease that may involve many genes that each make very small contributions. When that’s the case, it’s harder to find genetic markers.”

So Constantino’s group, in collaboration with the other co-principal investigator, Daniel H. Geschwind, M.D., Ph.D., and neuropsychiatric and genetics researchers at UCLA, is using a different approach. They report their findings in the April issue of the American Journal of Psychiatry.

“Although we once believed you either had this condition or you didn’t, we now know that there’s a continuous distribution of autism symptoms from very mild to very severe,” Constantino says.

That means in families where a child is autistic, parents and unaffected siblings may have very subtle communication impairments or behavioral tendencies that would be considered autistic only in their most severe forms. Those traits may indicate genetic tendencies that contribute to autism and now can be measured with a diagnostic interview tool called the Social Responsiveness Scale (SRS), which Constantino developed with his colleague Richard D. Todd, Ph.D., M.D., at Washington University.

Using the SRS to gather data about both children with autism and their unaffected parents and siblings allowed the researchers to take a more quantitative approach to find subtle symptoms of autism that aggregate in families. In all, they used the SRS to study members of 99 families who were part of the Autism Genetic Resource Exchange (AGRE).

“We characterized everyone using the quantitative measures that the Social Responsiveness Scale provides,” Constantino explains. “With the SRS, we looked not just at whether a person has autism but more systematically at the degree of autistic impairment. Then we analyzed their genetic material and found significant linkage to these symptoms on regions of chromosomes 11 and 17.”

Older survey methods also had flagged those regions of DNA, but those studies used samples more than three times larger than this study. Constantino and Geschwind believe the fact that they identified the same areas of DNA means that their quantitative method can find genes related to autism and that if used in bigger samples, it may be able isolate other suspicious regions of DNA that studies using traditional methods can’t find.

The researchers now have begun to make more detailed maps of the chromosome regions related to autism. They’re also using the SRS to study more families.

In theory, the greater statistical power of their method will be magnified as the researchers study larger numbers of people. They say that power may help them isolate many more genes that might contribute to autism spectrum disorders. They’ll also continue to look closely at genes in the suspicious DNA regions identified so far and try to figure out what’s going on at the genetic level to make some children autistic.

“We know that the dopamine D4 receptor gene is in the region we’ve identified on chromosome 11,” Constantino says. “That receptor is important in many brain functions. But there are many genes in the regions we’ve identified, and our focus is on refining the signal so that we can reduce the number of candidate genes and then look more closely at how those genes might be contributing to this devastating disorder.”

Constantino believes ultimately the search will lead to the discovery of many genes that contribute to autism and that scientists may need to find several of them before they begin to understand how genetic variations actually lead to the disorder.

“The genetic factors tend to interact with one another,” he says. “One gene might increase risk by 10 percent, but two genes, in the proper combination, might increase the risk 10-fold. We expect that as we find additional susceptibility factors the amount of their causal influence will increase exponentially, and we’ll get a clearer picture of how genes contribute to autism and may even find ways to intervene.”

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The Autism Genetic Resource Exchange (AGRE) is a collaborative gene bank designed to speed to pace of research to find the genes and ultimately the cure for autism. AGRE was established by the non-profit foundation Cure Autism Now.

For more information about autism studies at Washington University, please call Teddi Gray, research coordinator for the Social Developmental Studies program at (314) 286-0068.

Duvall JA, Lu A, Cantor RM, Todd RD, Constantino JN, Geschwind DH. A quantitative trait locus analysis of social responsiveness in multiplex autism families. American Journal of Psychiatry, vol. 164:4, pp. 656-662 April 2007

This research was supported by the National Institutes of Health and Cure Autism Now.

Related papers

Constantino JN, Todd RD. Intergenerational transmission of subthreshold autistic traits in the general population. Biological Psychiatry, vol. 57:6, pp. 655-660, March 15, 2005.

Constantino JN, Todd RD. Autistic traits in the general population. Archives of General Psychiatry, vol. 60:6, pp. 524-530, May 2003.

Washington University School of Medicine’s full-time and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children’s hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked fourth in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children’s hospitals, the School of Medicine is linked to BJC HealthCare.

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May 9, 2007 Posted by | Autism, DNA, Genetics, Global, Global Health Vision, Global News, Washington University | Leave a comment