Quinn Eastman

The next generation of biomedical engineering innovators

Congratulations to the winners of the InVenture innovation competition at Georgia Tech. The competition aired Wednesday night on Georgia Public Broadcasting. The winners get cash prizes, a free patent filing and commercialization service through Georgia Tech’s Office of Technology Transfer.

Several of the teams have Emory connections, through the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory, and the Atlanta Clinical & Translational Science Institute.

Emergency medical professionals know that intubation can be rough. The second place ($10,000) MAID team created a “magnetic assisted intubation device” that helps them place a breathing tube into the trachea in a smoother way. The MAID was designed by Alex Cooper, Shawna Hagen, William Thompson and Elizabeth Flanagan, all biomedical engineering majors. Their clinical advisor was Brian Morse, MD, previously a trauma fellow and now an Emory School of Medicine surgical critical care resident at Grady Memorial Hospital.

“When I first saw the device that the students had developed, I was blown away,” Morse told the Technique newspaper. “It’s probably going to change the way we look at intubation in the next five to 10 years.”

The AutoRhexis team, which won the People’s Choice award ($5,000), invented a device to perform the most difficult step during cataract removal surgery. It was designed by a team of biomedical and mechanical engineering majors: Chris Giardina, Rebeca Bowden, Jorge Baro, Kanitha Kim, Khaled Kashlan and Shane Saunders. They were advised by Tim Johnson, MD, who was an Emory medical student and is now a resident at Columbus Regional Medical Center.

The finalist Proximer team, advised by Emory surgeon Albert Losken, MD, developed a way to detect plastics in the body, which can help breast cancer survivors undergoing reconstruction.

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The Scientist ranks Emory one of top 15 best places to work for postdocs

This year, the readers of The Scientist magazine have ranked Emory University as the 11th best place to work for postdocs in the United States. Among Emory’s strengths, respondents cited training and mentoring, and career development opportunities.

The top U.S. institution was the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts. The top international institution was University College, London. Emory has previously ranked as high as number 4 (in 2006) in The Scientist’s best places to work for postdocs survey.

The ranking was based on responses from 2,881 nontenured life scientists working in academia, industry or noncommercial research institutions. 76 institutions in the United States and 17 international institutions were included.

Emory employs nearly 700 postdoctoral fellows in laboratories in the School of Medicine, Yerkes National Primate Research Center, Emory College, the Graduate School of Arts and Sciences, Rollins School of Public Health and Nell Hodgson Woodruff School of Nursing.

After receiving their PhD degrees, life sciences graduates launch their research careers by working for several years as postdoctoral fellows in the laboratories of established scientists. In addition to engaging in sometimes grueling laboratory research, many postdocs teach, mentor graduate and undergraduate students and apply for their own funding on a limited basis.

 

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One reason why SIV-infected sooty mangabeys can avoid AIDS

Sooty mangabeys are a variety of Old World monkey that can be infected by HIV’s cousin SIV, but do not get AIDS. Emory immunologist and Georgia Research Alliance Eminent Scholar Guido Silvestri, MD, has been a strong advocate for examining non-human primates such as the sooty mangabey, which manage to handle SIV infection without crippling their immune systems. Silvestri is division chief of microbiology and immunology at Yerkes National Primate Research Center.

Research shows sooty mangabeys have T cells that can do the same job as those targeted by SIV, even if they don't have the same molecules on their surfaces

A recent paper in the Journal of Clinical Investigation reveals that sooty mangabeys have T cells that perform the same functions as those targeted by SIV and HIV, but have different clothing.

Silvestri and James Else, the animal resources division chief at Yerkes, are co-authors on the paper, while Donald Sodora at Seattle Biomedical Research Institute is senior author.

One main target for SIV and HIV is the group of T cells with the molecule CD4 on their surfaces. These are the “helper” T cells that keep the immune system humming. Doctors treating people with HIV infections tend to keep an eye on their CD4 T cell counts.

In the paper, the scientists show that sooty mangabeys infected with SIV lose their CD4 T cells, without losing the ability to regulate their immune systems. What’s remarkable here is that sooty mangabeys appear to have “double negative” or DN T cells that can perform the same functions as those lost to SIV infection, even though they don’t have CD4.

CD4 isn’t just decoration for T cells. It’s a part of how they recognize bits of host or pathogen protein in the context of MHC class II (the molecule that “presents” the bits on the outside of target cells). Somehow, the T cells in sooty mangabeys have a way to get around this requirement and still regulate the immune system competently. How they do this is the topic of ongoing research.

The authors write:

It will be important to assess DN T cells in HIV-infected patients, particularly to determine whether these cells are preserved and functional in long-term nonprogressors. These efforts may lead to future immune therapies or vaccine modalities designed to modulate DN T cell function. Indeed, the main lesson we have learned to date from this cohort of SIV-infected CD4-low mangabeys may be that managing immune activation and bolstering the function of nontarget T cells through better vaccines and therapeutics has the potential to contribute to preserved immune function and a nonprogressive outcome in HIV infection even when CD4+ T cell levels become low.

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Emory/Georgia Tech: partners in creating heart valve repair devices

Vinod Thourani, associate professor of cardiac surgery at Emory School of Medicine, along with Jorge Jimenez and Ajit Yoganathan, biomedical engineers at Georgia Tech and Emory, have been teaming up to invent new devices for making heart valve repair easier.

At the Georgia Bio and Atlanta Clinical and Translational Science Institute’s second annual conference on academic/industry partnerships, Thourani described how he and his colleagues developed technology that is now being commercialized.

Apica Cardiovascular co-founders (l-r) James Greene, Vinod Thourani, Jorge Jimenez and Ajit Yoganathan

Apica Cardiovascular was founded based on technology invented by Jimenez, Thourani, Yoganathan and Thomas Vassiliades, a former Emory surgeon.

Thourani is associate director of the Structural Heart Program at Emory.

Yoganathan is director of the Cardiovascular Fluid Mechanics Laboratory at Georgia Tech and the Center for Innovative Cardiovascular Technologies.

The technology simplifies and standardizes a technique for accessing the heart via the apex, the tip of the heart’s cone pointing down and to the left. This allows a surgeon to enter the heart, deliver devices such as heart valves or left ventricular assist devices, and get out again, all without loss of blood or sutures.

Schematic of transapical aortic valve implantation. The prosthesis is implanted within the native annulus by balloon inflation.

At the conference, Thourani recalled that the idea for the device came when he described a particularly difficult surgical case to Jimenez.  Thourani said that a principal motivation for the device came for the need to prevent bleeding after the valve repair procedure is completed.

With research and development support from the Coulter Foundation Translational Research Program and the Georgia Research Alliance VentureLab program, the company has already completed a series of pre-clinical studies to test the functionality of their device and its biocompatibility.

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Brain chemical linked to migraines could be anxiety target

Neuroscientist Michael Davis, PhD, and his colleagues have devoted years to mapping out the parts of the brain responsible for driving fear and anxiety. In a recent review article, they describe the differences between fear and anxiety in this way:

Fear is a generally adaptive state of apprehension that begins rapidly and dissipates quickly once the threat is removed (phasic fear). Anxiety is elicited by less specific and less predictable threats, or by those that are physically or psychologically more distant (sustained fear).

Michael Davis is an investigator at Yerkes National Primate Research Center and Emory School of Medicine

A host of their studies suggest that one part of the brain, the amygdala, is instrumental in producing “phasic fear,” while the bed nucleus of the stria terminalis (BNST) is important for “sustained fear.”

In a new report in the Journal of Neuroscience, Davis’ team describes the effects of a brain communication chemical, which is known primarily for its role in driving migraine headaches, in enhancing anxiety.

“This is the first study to show a role of this peptide, in a brain area we’ve identified as being important for anxiety.  This could lead to new drug targets to selectively reduce anxiety,” Davis says.

His team found that introducing calcitonin gene-related peptide (CGRP) into rats’ BNSTs can increase the anxiety they experience from loud noises or light, in that they startle more and avoid well-lit places. This peptide appears to activate other parts of the brain including the amygdala, hypothalamus and brainstem, producing fear-related symptoms.

Slice of rat brain showing the bed nucleus of the stria terminalis (BNST) and the central amygdala (Ce)

If Davis and his colleagues block CGRP’s function by introducing a short, decoy version of CGRP into the BNST, the reverse does not happen: the rats are not more relaxed. However, the short version does block the startle-enhancing effects of a smelly chemical produced by foxes that scientists use to heighten anxiety-like behavior in rats. This suggests that interfering with CGRP can reduce fear-related symptoms in situations where the rats are already under stress.

“Blockade of CGRP receptors may thus represent a novel therapeutic target for the treatment of stress-induced anxiety and related psychopathologies such as post-traumatic stress disorder,” says the paper’s first author, postdoctoral fellow Kelly Sink.

In fact, experimental drugs that work against CGRP are already in clinical trials to treat migraine headaches. But first, Sink reports that she and her colleagues are examining the relationship between CGRP and the stress hormone CRF (corticotropin-releasing factor) — another target of pharmacological interest — in the parts of the brain important for fear responses.

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Another avenue of HIV trickery reveals opportunity

Emory and University of Rochester researchers have discovered an extra way by which HIV adapts to survive in a hiding spot in the human immune system. The results are published in the Journal of Biological Chemistry.

A team led by Baek Kim from the University of Rochester and Raymond Schinazi from Emory found that when HIV faces a shortage of the building blocks it usually uses to replicate, the virus adapts by using different building blocks. The discovery may offer scientists a new way to try to stop the virus.

One of HIV’s favorite hiding spots is an immune cell called a macrophage, whose job is to chew up and destroy foreign invaders and cellular debris. One can think of macrophages as worker bees: they don’t reproduce because they’re focused on getting stuff done.

Raymond Schinazi, PhD, DSc, is director of the Laboratory of Biochemical Pharmacology at Emory's Center for AIDS Research

Normally, HIV uses “dNTPs” (building blocks of DNA), but dNTPs are found at very low levels in macrophages because they’ve stopped dividing and making new DNA. Current drugs generally target dNTPs, and aim at the infection in a different type of cells: T cells.

Macrophages do have high levels of RNA building blocks (“rNTPs”). The team found that HIV uses primarily rNTPs instead of dNTPs to replicate inside macrophages. When the team blocked the ability of the virus to interact with rNTPs, its ability to replicate in macrophages was cut by more than 90 percent.

“The first cells that HIV infects in the genital tract are non-dividing target cell types such as macrophages,” Kim says. “Current drugs were developed to be effective only when the infection has already moved beyond these cells. Perhaps we can use this information to help create a microbicide to stop the virus or limit its activity much earlier.”

Compounds that interfere with the use of rNTPs already exist and have been tested as anti-cancer drugs.

“We are now developing new anti-HIV drugs jointly based on this novel approach that are essentially non-toxic and can be used to treat and prevent HIV infections,” Schinazi says.

Baek Kim, PhD

The first authors of the paper are graduate students Edward Kennedy from Rochester and Christina Gavegnano from Emory. Other authors include graduate students Laura Nguyen, Rebecca Slate and Amanda Lucas from Rochester, and postdoc Emilie Fromentin from Emory.

The research was funded by the National Institute of Allergy and Infectious Disease and the Department of Veterans Affairs.

University of Rochester press release

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Reassuring news on viral immunity + HIV vaccine

A recent paper in Journal of Immunology suggests that a platform for an HIV vaccine developed by Yerkes National Primate Research Center scientists won’t run into the same problems as another HIV vaccine. Postdoc Sunil Kannanganat is the first author of the JI paper, with Emory Vaccine Center researcher Rama Amara as senior author.

Harriet Robinson, MD and Rama Rao Amara, PhD

Many HIV vaccines have been built by putting genes from HIV into the backbone of another virus. Some have used a modified cold virus (adenovirus 5). The vaccine developed at Yerkes uses modified vaccinia Ankara (MVA), a relative of smallpox and chicken pox.

Read more

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Challenges in islet transplantation

Two recent research papers from the Emory Transplant Center describe research on pancreatic islet transplantation, an experimental procedure that could help people with type I diabetes live without daily insulin injections.

Islet transplantation may offer people with type I diabetes the ability to produce their own insulin again

As with other types of transplantation, the challenge with islet transplantation is to avoid rejection of the donated organ and to balance that goal against side effects from the drugs needed to control the immune system. These papers illustrate how that balancing act is especially complex.

In the last decade, transplant specialists developed a method for islet transplantation named the “Edmonton protocol” after pioneers at the University of Alberta. While the emergence of this method was a major step forward, there are limitations:

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Secrets of the elite: Effective immune control of HIV

A small minority of individuals infected with HIV — about one in 300 – are naturally able to suppress viral replication with their immune systems, and can keep HIV levels extremely low for years. Doctors have named these individuals “elite controllers.”

“These individuals have naturally achieved the outcome sought by HIV vaccine researchers worldwide.  Studying them will ultimately inform the design of a more effective HIV vaccine,” says Vincent Marconi, a physician-scientist at Grady Health System’s Infectious Disease Clinic on Ponce de Leon and an associate professor in the Emory School of Medicine.

Vincent Marconi, MD

Marconi is a co-author (along with investigators at over 200 institutions) on a genomics study of elite controllers published Thursday in Science Express. Led by Bruce Walker at Massachusetts General Hospital and Paul de Bakker at the Broad Institute and Brigham and Women’s Hospital in Boston, the team of researchers scanned through the genomes of close to 1,000 elite controllers and 2,600 people with progressive HIV infection. They identified several sites linked with immune control of HIV, all in a region encoding HLA proteins.

HLA proteins play key roles in activating T cell immunity, and are also necessary for the development of T cells. They grab onto segments of proteins, called peptides, inside the cell and carry them to the cell membrane. In the right context, certain viral peptides can mark infected cells for destruction by “killer” T cells.

Previously, MGH/MIT researchers theorized that people with certain forms of their HLA genes develop T cells with a restricted repertoire, yet broader activity. Their T cells would be more likely to still recognize HIV when the virus mutates. A drawback is that these individuals may have a higher risk for developing autoimmune diseases. The theory is described in more detail in this Nature News article.

Marconi is continuing his part of this research into what makes elite controllers’ immune systems special, which he began at the Department of Defense Infectious Disease Clinical Research Program, in collaboration with Eric Hunter, co-director of Emory’s Center for AIDS Research, and research associate Ling Yue at Emory Vaccine Center. The research is supported by the Center for AIDS Research and the National Institute of Allergy and Infectious Diseases.

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