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Adjuvants: once immunologists’ “dirty little secret”

Two presentations on Emory research at last week’s AIDS Vaccine 2010 conference concerned adjuvants. These are substances that act as amplifiers, stimulating the immune system while keeping its focus on the specific components of a vaccine.

Charlie Janeway (1943-2003)

Immunologist Charlie Janeway once described adjuvants as immunology’s “dirty little secret,” because for a long time scientists did not know how they worked. Some adjuvants can sound irritating and nasty, such as alum and oil emulsion. Alum is the only vaccine adjuvant now licensed for human clinical use in the US. Over the last few years, scientists have learned that adjuvants rev up what is now known as the “innate immune system,” so that the body knows that the vaccine is something foreign and dangerous.

Rama Rao Amara, a vaccine researcher at Emory Vaccine Center and Yerkes National Primate Research Center, and Harriet Robinson, former head of microbiology and immunology at Yerkes and now chief scientific officer at the firm GeoVax, both described extra ingredients for the DNA/MVA vaccine that Robinson designed while at Yerkes in collaboration with NIH researchers.

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What if HIV was just another virus

Imagine that HIV was a “normal” virus. An infection begins and the body responds, without getting trapped in a cycle where CD4+ T cells are consumed and the immune system is crippled.

SIV can infect sooty mangabeys but it doesn't cripple their immune systems.

The attractiveness of this idea explains some of why scientists are interested in sooty mangabeys and other non-human primates. HIV’s relative SIV can infect them, but they usually don’t develop immunodeficiency.

At last week’s AIDS Vaccine 2010 conference, Cynthia Derdeyn reported her laboratory’s recent results investigating sooty mangabeys, which don’t develop high levels of neutralizing antibodies against SIV when infected. Derdeyn’s group at Emory Vaccine Center and Yerkes National Primate Research Center studies how HIV and SIV evade the immune system.

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Strengthening community engagement in HIV vaccine research

Paula Frew, PhD

The scientific part of the AIDS Vaccine 2010 meeting began Tuesday evening with an exciting summary of issues facing the field from NIAID director Tony Fauci. But before that, participants in this year’s conference got a chance to warm up with several “satellite sessions.”

One of them, “Effective Community Engagement in HIV Vaccine Research Among Communities and Researchers,” was organized by Paula Frew, PhD, director of health communications and applied community research at Emory’s Hope Clinic.

Two prominent themes emerged from this session. The first was that community members should be involved in clinical trials at every step of the process: from design and recruitment to dissemination of results.

“In the past, scientists often came to the community late in the process, after a protocol for a study was already approved, and said: “Will you support what we’ve already decided?” said Steve Wakefield of HIV Vaccine Trials Network. “This doesn’t work.”

The Joint United Nations Programme on HIV/AIDS and AVAC presented proposed guidelines for “good participatory practice,” analogous to good clinical practices.

Another theme that emerged from the satellite session was the search for more flexible “adaptive” clinical trial formats. Glenda Gray from South Africa’s University of the Witwatersrand emphasized that adaptive trials could be faster and avoid enrollment of large numbers of patients unnecessarily.

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Smart mice, clever names and some context

This week a variety of media outlets and science-oriented Web sites had fun with research at Emory — published recently in PNAS — investigating a gene that appears to limit some forms of learning and memory.

Mice with a disabled RGS14 gene remembered objects in their cages more easily and learned to navigate water mazes better, pharmacologist John Hepler and his colleagues found. Since the presence of a functional RGS14 gene holds mice back mentally, Hepler and his colleagues have been jokingly calling it “the Homer Simpson gene.”

This description struck a chord; the Atlantic magazine even embellished the story with a video showing the “D’oh”-ey cartoon character evolving from a single cell into a human couch potato.

It’s important to recognize that smart mice are not so surprising to scientists anymore. Back in 1999, scientists at Princeton announced the creation of “Doogie Howser” mice (named after a precocious doctor from another TV series). These critters performed better than normal lab mice in some of the same tests that Hepler’s team used to evaluate the RGS14-deleted mice.

One important difference: the Doogie mice had all their normal genes, and were overproducing a NMDA receptor gene involved in helping neurons communicate. Still, as a helpful 2009 round-up in Nature Reviews Neuroscience explains, scientists have found several single-gene knock-out mice that do better on tests of learning and memory. Many of these genetic alterations affect the process of long term potentiation, a process where neurons that get stimulated at the same time have the connections between them grow stronger.

RGS14 is turned on primarily in the CA2 region of the hippocampus

What makes the RGS14 gene an intriguing case is that it’s primarily turned on in the enigmatic CA2 region of the hippocampus. The CA2 region is normally relatively resistant to long-term potentiation and is also more hardy in situations of stroke or seizure.

Hepler observes that the vasopressin receptor 1b gene is also turned on predominantly in the CA2 region, and seems to be involved in aggression and social memory. He and his colleagues are planning to examine whether the RGS14-disabled mice have altered capabilities in those areas. Conveniently, Larry Young’s laboratory at Yerkes National Primate Research Center has been investigating the functions of vasopressin receptors in voles.

One last note: scientists in Spain have reported in Science that they can generate a variety of smart mice by putting the RGS14 gene on overdrive in a part of the brain where it’s not usually turned on. So whatever precise function RGS14 has, it doesn’t always dumb things down.

Posted on by Quinn Eastman in Neuro 1 Comment

Initial Results of Heart Valve Study Encouraging

 

Emory heart patient, Glenrose Gay of Vidalia was the first person in GA to receive a new aortic valve via catheter. Pictured here in 2007 with Emory cardiologists, Drs. Peter Block (left) and Vasilis Babaliaros.

Since October 2007, Emory University Hospital has been one of approximately 20 hospitals nationwide, and the only site in Georgia, studying a new non-surgical treatment option for patients with failing aortic valves. The life threatening heart condition,aortic stenosis, affects tens of thousands of Americans each year when the aortic valve tightens or narrows, preventing blood from flowing through normally.

As part of the Phase II clinical trial, researchers have been performing transcatheter aortic valve implantation (TAVI) comparing this procedure with traditional, open-heart surgery or medical therapy in high-risk patients with aortic stenosis.

During the TAVI procedure, doctors create a small incision in the groin or chest wall and then feed the new valve, mounted on a wire mesh on a catheter, and place it where the new valve is needed. This offers a non-invasive way for doctors to treat patients who are too ill or frail to endure the traditional open-heart surgical approach.

The study, published Wednesday in The New England Journal of Medicine (NEJM) followed 358 patients who received either catheter-delivered valves or standard non-surgical treatment.

The findings showed that patients who had replacement heart valves delivered by catheter were more likely to survive a year than patients who were treated without replacing their original valves. According to the authors, catheter-delivered valves “should be the new standard of care” for patients who are not able to undergo surgery.

“These results show great promise for patients with severe aortic stenosis and help us make a giant step forward in our battle against this common disease,” says Peter Block, MD, professor of medicine, Emory School of Medicine and principal investigator of the study at Emory. “They are especially important since the number of people with failing valves is expected to greatly increase as baby boomers continue to age.”

Aortic valve stenosis often occurs with age, most commonly among elderly patients over 70 years of age, but can surface earlier in life in those with rheumatic heart disease or congenital abnormalities of the valve.

Approximately 90 patients have received new valves at Emory since the clinical trial started in 2007. Researchers hope to receive FDA approval in late 2011.

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Health sciences on the A-List

Parade magazine’s back-to-school survey in the August 22 issue and website included Emory on its A-list of colleges with excellent programs in the health sciences.

“Good health programs combine strong academic preparation with a hands-on approach and offer a wide variety of choice,” said the magazine.

“Emory University, a stand-out in health sciences, has the Centers for Disease Control virtually next door.”

Emory also made the A-list for its pre-med programs:

“At Emory, students interested in the field of medicine have the opportunity to gain first-hand exposure to the daily routine of the physician through their House Staff Assistant program. Students witness all aspects of the job and become integral parts of the medical team, which consists of attending physicians, resident physicians, and medical students.”

The list of outstanding schools was based on the recommendations of 43 top guidance counselors across the country.

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Reading the blood: metabolomics

In the Star Trek series, Dr. McCoy could often instantly diagnose someone’s condition with the aid of his tricorder. Medicine on 21st century Earth has not advanced quite this far, but scientists’ ideas of how to use “metabolomics” are heading in this direction.

What is metabolomics? Just as genomics means reading the DNA in a person or organism, and assessing it and comparing it to others, metabolomics takes the same approach to all the substances produced as part of the body’s metabolism: watching what happens to food, drugs and chemicals we are exposed to in the environment.

This means dealing with a huge amount of information. Human genomes may be billions of letters (base pairs) in length, but at least there are only four choices of letter!

A recent article in Chemical & Engineering News explores this concept of the “exposome” and quotes Dean Jones. He and his colleagues recently described how they can use sophisticated analytical techniques to resolve thousands of substances in human plasma. Jones is the director of the Clinical Biomarkers Laboratory at Emory University School of Medicine. The paper is in the journal Analyst, published by the Royal Society of Chemistry.

Analytical techniques can discern more than 2500 metabolites from human plasma within 10 minutes

Using a drop of blood, within ten minutes the researchers can discern more than 2,500 substances in a reproducible way. One fascinating tidbit: when they compared the metabolic profiles for four healthy individuals, most of the “peaks” were common between individuals but 10 percent were unique.

The potential uses for this type of technology are staggering.

Jones reports he has been working with researchers at Yerkes National Primate Research Center to discern early signs of neurodegeneration in transgenic monkeys with Huntington’s disease. He has been collaborating with clinical nutrition specialist Tom Ziegler to examine how diet interacts with oxidative stress, and with lung biology to identify markers for fetal alcohol exposure in animal models.

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Preterm infants born at unspecialized hospitals face higher risk of death

Very low-birth-weight (VLBW) and very preterm (VPT) infants not born in highly specialized, level III hospitals have a higher risk of neonatal and pre-discharge death compared to similar infants born at level III hospitals, according to a recent Journal of the American Medical Association (JAMA) study.

Lead study author Sarah Lasswell, MPH, and colleagues at the Rollins School of Public Health conducted a large-scale analysis of previous research to examine the relationship between hospital level at birth and neonatal (generally the first four weeks after birth) or pre-discharge mortality for VLBW (weighing 53 ounces or less) and VPT (32 weeks or less gestation) infants to determine the importance of level of care at birth to survival.

Lasswell and colleagues found that VLBW infants born in non-level III hospitals had a 62 percent increase in odds of neonatal/pre-discharge death compared with VLBW infants born in level III hospitals. In addition, VPT infants born in lower-level hospitals had a 55 percent increase in odds of neonatal/pre-discharge mortality compared with those born in level III facilities.

“The results of this review confirm a primary premise on which perinatal regionalization systems are based: high-risk infants have higher mortality rates when born outside hospitals with the most specialized levels of care,” Lasswell and colleagues write.

“Strengthening perinatal regionalization systems in states with high percentages of VLBW and VPT infants born outside of level III centers could potentially save thousands of infant lives every year.”

About 13 million babies are born prematurely every year – nearly 10 percent of all newborns – and more than 1 million premature babies die each year, according to the March of Dimes.

The study, “Perinatal Regionalization for Very-Low-Birth-Weight and Very Preterm Infants: A Meta-Analysis,” was published in the Sept. 1, 2010, issue of JAMA. It was conducted as part of Lasswell’s graduate research at the Rollins School of Public Health under the direction of Roger Rochat, MD. Lasswell is now a researcher at the U.S. Centers for Disease Control.

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Old-school medicine: relief of skin irritation with gentian violet

In the September issue of the Journal of the American Academy of Dermatology, Jack Arbiser and colleagues describe the use of gentian violet to provide some relief to a patient who came to the emergency room with a painful skin irritation. Arbiser is a professor of dermatology at Emory University School of Medicine.

A coal-tar dye which is inexpensive and available over the counter, gentian violet was first synthesized in the 19th century. It has been used as a component of paper ink, a histological stain, and an antibiotic or antifungal agent, especially before the arrival of penicillin.

“Clinicians should not forget about gentian violet for immediate pain relief and antibiotic coverage,” the authors conclude in their case report.

Biopsy of the patient's irritated skin shows that the gene angiopoetin-2 (dark brown) is turned on

In addition to its antibiotic properties, Arbiser reports that gentian violet has antiinflammatory effects, possibly because of its inhibition of the enzyme NADPH oxidase and the gene angiopoetin-2.

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A family of troublemakers known as XMRV

A long-delayed paper on the connection between chronic fatigue syndrome and XMRV (xenotropic murine leukemia virus-related virus) finally surfaced last week in PNAS. Astute readers may recall that XMRV has also been linked to prostate cancer.

Detecting XMRV in prostate tissue. A variety of assays (neutralizing antibodies, polymerase chain reaction or fluorescence in situ hybridization) may be used to look for XMRV

The twist from last week’s paper is that the NIH/FDA team, led by Harvey Alter, didn’t find viruses all with the same sequence in chronic fatigue patients. Instead, they found a cluster of closely related, but different, viruses. While confusing, these results may explain why tests for the presence of the virus that are based on viral DNA sequences may have generated varying (and conflicting) results. An alternative assay based on antibodies, such as the one urologist John Petros and colleagues at Emory developed, may be useful because it casts a wider net.

Pathologist Hinh Ly has been diving into the XMRV field, with a recent paper in Journal of Virology describing what “gateway” (receptor) molecule the virus uses to sneak into cells and what kinds of cells in the prostate it can infect.

In a collaboration with Ila Singh at the University of Utah, antiviral drug expert Raymond Schinazi has found that a number of drugs active against HIV also stop XMRV. This offers some hope that if doctors can detect members of the XMRV family, and figure out what they’re up to, they might be able to combat the troublemakers as well.

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