Health News
The future of medicine: Insert chip, cure disease?
By April Frawley Birdwell
GAINESVILLE, Fla. - Imagine a chip, strategically placed in the brain, that could prevent epileptic seizures or allow someone who has lost a limb to control an artificial arm just by thinking about it.
It may sound like science fiction, but University of Florida researchers are developing devices that can interpret signals in the brain and stimulate neurons to perform correctly, advances that might someday make it possible for a tiny computer to fix diseases or even allow a paralyzed person to control a prosthetic device with his thoughts.
Armed with a $2.5 million grant they received this year from the National Institutes of Health, UF researchers from the College of Medicine, the College of Engineering and the McKnight Brain Institute have teamed up to create a "neuroprosthetic" chip designed to be implanted in the brain. They are currently studying the concept in rats but are aiming to develop a prototype of the device within the next four years that could be tested in people.
The initial goal? To correct conditions such as paralysis or epilepsy.
"We really feel like if we can do this, we'll have the technology to offer new options for patients," said Justin Sanchez, Ph.D., director of the UF Neuroprosthetics Research Group and an assistant professor of
pediatric neurology, neuroscience and biomedical engineering. "There's kind of a revolution going on right now in the neurosciences and biomedical engineering. People are trying to take engineering approaches for directly interfacing with the brain.
"The hope is we can cure more immediately a variety of diseases."
Researchers have been able to decode brain activity for years using electroencephalography. Referred to commonly as an EEG, this technology involves placing a sensor-wired net over the head to measure brain activity through the scalp. But the technology wasn't quite sensitive enough to allow researchers to decode brain signals as precisely as needed, Sanchez said. Now researchers are focusing on decoding signals
from electrodes placed directly into the brain tissue using wires the width of a strand of hair.
"(Scientists have) realized that by going inside the brain we can capture so much more information, we can have much more resolution," Sanchez said.
The chip UF researchers are seeking to develop would be implanted directly into the brain tissue, where it could gather data from signals, decode them and stimulate the brain in a self-contained package without wires. In the interim, UF researchers are studying implantable devices in rats and are evaluating an intermediate form of the technology - placing electrodes on the surface of the brain - in people.
UF researchers have developed new techniques using surface electrodes to access signals almost as precisely as they could with sensors implanted in the brain, according to findings the researchers published in May in the Journal of Neuroscience Methods. Developing these techniques is a big step forward in understanding how to best decode a patient's intent from their brain waves and should have broad implications for delivering therapy, Sanchez said.
To gather data about the brain's sophisticated cues, which vary from person to person, Sanchez studies the brain signals of children with epilepsy who are scheduled to undergo surgery to remove the part of the brain that is causing seizures. These patients often must be monitored for several days to weeks with electrodes placed directly on the brain. Doctors use this to pinpoint the problem area when a child has another seizure.
Because the children already have electrodes in place, Sanchez is able to use the data gathered from them to understand more about the brain's signals in general.
UF researchers are also working on intermediate concepts that could be wearable, like a diabetes pump, Sanchez said.
"We have intermediate designs that connect to the brain, interpret signals and can wirelessly send commands to devices," he said. "This is another path of technology we're pursuing."
To create these technologies, Sanchez is in the process of developing a center for brain-machine interfaces at UF with faculty from the College of Engineering, including Jose C. Principe, Ph.D.; John G. Harris, Ph.D.; Toshikazu Nishida, Ph.D.; and Rizwan Bashirullah, Ph.D.
But several challenges face researchers in bringing these technologies to patients, said Steven J. Schiff, M.D., Ph.D., a professor of engineering and neuroscience at The Pennsylvania State University and director of the Penn State Center for Neural Engineering.
For patients with epilepsy, who often have to take several medications or undergo surgery for relief from debilitating seizures, a neuroprosthetic device could be the best form of treatment, Schiff said, adding that more work needs to be done to understand the mechanics of what causes diseases such as epilepsy and Parkinson's.
"The challenge is not so much the technology," Schiff said. "The challenge is to use that technology wisely."
The day may not be too far off when patients can control a prosthetic hand or leg just by thinking about it, Sanchez said.
"It's becoming a reality," Sanchez said. "We're designing electronics that we can interface with biological systems and we can use that to help people."
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UF to lead research on life-threatening fungus
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By Melanie Fridl Ross
GAINESVILLE, Fla. - Hear the word fungus, and mushrooms and mold might leap to mind. But the University of Florida is about to house the nation's first research repository for one species that has nothing to do with pizza toppings or marbling blue cheese: Aspergillus, which increasingly poses a major health threat to cancer patients and transplant recipients.
The National Institutes of Health has awarded $9 million over the next seven years to the effort. UF researchers are collaborating with colleagues at Duke University, Brigham and Women's Hospital in Boston and the Dana-Farber Cancer Institute, who will funnel patients' respiratory, urine and blood samples to UF. The repository will support research aimed at learning more about the fungus and efforts to develop more accurate tests to detect it in patients.
"Aspergillus is everywhere, particularly in the air we breathe; all of us breathe it in all the time," said principal investigator John Wingard, M.D., director of UF's blood and marrow transplant program and deputy director of the UF Shands Cancer Center. "On a windy day, especially in a dusty environment or every time some dirt gets moved around, lots of these organisms get aerosolized."
The number of people contracting Aspergillus infections jumped enormously in the 1990s, Wingard said, and those with weakened immune systems are particularly susceptible. Aspergillosis is the leading cause of death from infection in bone marrow transplant and leukemia patients, as well as among those who receive certain other solid organ transplants, he said. About 15 percent of all bone marrow transplant patients, for example, will develop an infection from Aspergillus; of those, about two-thirds die.
"We haven't had good treatments, we haven't had good prevention methods and, most importantly, we haven't had good diagnostic methods to identify which patients have these infections," Wingard said. "Since we often don't recognize that patients have aspergillosis until very late in the course of the infection, by the time we try to treat the infection it is often so advanced we have very poor prospects of bringing it under control."
A number of hospitals undergoing renovations have experienced outbreaks, in many cases after the organism contaminated ventilation systems or fireproofing materials. Despite hospitals' infection control measures aimed at minimizing risks, including special air filtration systems designed to filter out Aspergillus and other infectious agents, facilities can still have problems and sometimes have even had to temporarily close their patient-care units.
"You and I have a good healthy defense, so while we may be colonized by the organisms, we rarely get serious infections," Wingard said. "But if we become immunocompromised, those organisms can be deposited on the mucosal surface of nasal passages, the sinuses and the bronchi, and they can start invading and can cause very serious, deadly infections."
Complicating the picture is that aspergillosis is frequently mistaken for bacterial pneumonia, and tests for the infection often are initially negative.
"Historically, our only means of diagnosing these infections has been by growing the organism from patient's specimens in the laboratory and then having it identified by an experienced mycologist," said Barbara D. Alexander, M.D., the project's co-principal investigator and director of transplant infectious diseases services and the clinical mycology laboratory at Duke University Medical Center. "These conventional methods for diagnosing fungal disease are slow and lack sensitivity. Furthermore, many times the patients are too sick to tolerate the invasive procedures, such as lung biopsy, in order to obtain the samples for laboratory testing."
Wingard said two-thirds of the time tests are negative even though patients have the infection.
"That's the biggest challenge - we may suspect patients have the infection but we can't really know with certainty from currently available tests whether they truly are infected or not," he said. "We end up making clinical decisions about using drugs that may be toxic or using the wrong drugs in patients when we are not sure whether they have this deadly infection."
Officials are hoping to collect samples from about 200 patients a year for the next seven years to better characterize the fungus and improve the diagnostic accuracy and speed of tests used to detect aspergillosis. The repository will include samples from patients with confirmed infections that will be compared with samples from patients whose diagnosis is less clear and with samples from patients who are at high-risk but not infected.
Researchers also will work with Emory University, Indianapolis-based MiraVista Diagnostics, and the University of Manchester in England to evaluate existing tests and develop new, more accurate and less invasive ones.
While more potent treatment regimens are improving prospects for patients, so-called emerging pathogens - viruses, bacteria and fungi - are a growing medical problem, Wingard said.
"With advancing medical technology and more powerful antibiotics, patients are living longer," he said. "We have a growing population of patients who are susceptible to very serious infections by viruses, bacteria and fungi that in years past were not medical problems."
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