Posts tagged medicine
Articles and news from the latest research reports.
Cranial surgery is tricky business, even under 21st-century conditions (think aseptic environment, specialized surgical instruments and copious amounts of pain medication both during and afterward).
However, evidence shows that healers in Peru practiced trepanation — a surgical procedure that involves removing a section of the cranial vault using a hand drill or a scraping tool — more than 1,000 years ago to treat a variety of ailments, from head injuries to heartsickness. And they did so without the benefit of the aforementioned medical advances.
Excavating burial caves in the south-central Andean province of Andahuaylas in Peru, UC Santa Barbara bioarchaeologist Danielle Kurin and her research team unearthed the remains of 32 individuals that date back to the Late Intermediate Period (ca. AD 1000-1250). Among them, 45 separate trepanation procedures were in evidence. Kurin’s findings appear in the current issue of the American Journal of Physical Anthropology.
“When you get a knock on the head that causes your brain to swell dangerously, or you have some kind of neurological, spiritual or psychosomatic illness, drilling a hole in the head becomes a reasonable thing to do,” said Kurin, a visiting assistant professor in the Department of Anthropology at UCSB and a specialist in forensic anthropology.
According to Kurin, trepanations first appeared in the south-central Andean highlands during the Early Intermediate Period (ca. AD 200-600), although the technique was not universally practiced. Still, it was considered a viable medical procedure until the Spanish put the kibosh on the practice in the early 16th century.
But Kurin wanted to know how trepanation came to exist in the first place. And she looked to a failed empire to find some answers.
“For about 400 years, from 600 to 1000 AD, the area where I work — the Andahuaylas — was living as a prosperous province within an enigmatic empire known as the Wari,” she said. “For reasons still unknown, the empire suddenly collapsed.” And the collapse of civilization, she noted, brings a lot of problems.
“But it is precisely during times of collapse that we see people’s resilience and moxie coming to the fore,” Kurin continued. “In the same way that new types of bullet wounds from the Civil War resulted in the development of better glass eyes, the same way IED’s are propelling research in prosthetics in the military today, so, too, did these people in Peru employ trepanation to cope with new challenges like violence, disease and depravation 1,000 years ago.”
Kurin’s research shows various cutting practices and techniques being employed by practitioners around the same time. Some used scraping, others used cutting and still others made use of a hand drill. “It looks like they were trying different techniques, the same way we might try new medical procedures today,” she said. “They’re experimenting with different ways of cutting into the skull.”
Sometimes they were successful and the patient recovered, and sometimes things didn’t go so well. “We can tell a trepanation is healed because we see these finger-like projections of bone that are growing,” Kurin explained. “We have several cases where someone suffered a head fracture and were treated with the surgery; in many cases, both the original wound and the trepanation healed.” It could take several years for the bone to regrow, and in a subset of those, a trepanation hole in the patient’s head might remain for the rest of his life, thereby conferring upon him a new “survivor” identity.
When a patient didn’t survive, his skull (almost never hers, as the practice of trepanation on women and children was forbidden in this region) might have been donated to science, so to speak, and used for education purposes. “The idea with this surgery is to go all the way through the bone, but not touch the brain,” said Kurin. “That takes incredible skill and practice.
“As bioarchaeologists, we can tell that they’re experimenting on recently dead bodies because we can measure the location and depths of the holes they’re drilling,” she continued. “In one example, each hole is drilled a little deeper than the last. So you can imagine a guy in his prehistoric Peruvian medical school practicing with his hand drill to know how many times he needs to turn it to nimbly and accurately penetrate the thickness of a skull.”
Some might consider drilling a hole in someone’s head a form of torture, but Kurin doesn’t perceive it as such. “We can see where the trepanations are. We can see that they’re shaving the hair. We see the black smudge of an herbal remedy they put over the wound,” she noted. “To me, those are signs that the intention was to save the life of the sick or injured individual.”
The remains Kurin excavated from the caves in Andahuaylas comprise perhaps the largest well-contextualized collection in the world. Most of the trepanned crania already studied reside in museums such as the Smithsonian Institution, the Field Museum of Natural History or the Hearst Museum of Anthropology. “Most were collected by archaeologists a century ago and so we don’t have good contextual information,” she said.
But thanks to Kurin’s careful archaeological excavation of intact tombs and methodical analysis of the human skeletons and mummies buried therein, she knows exactly where, when and how the remains she found were buried, as well as who and what was buried with them. She used radiocarbon dating and insect casings to determine how long the bodies were left out before they skeletonized or were mummified, and multi-isotopic testing to reconstruct what they ate and where they were born. “That gives us a lot more information,” she said.
“These ancient people can’t speak to us directly, but they do give us information that allows us to reconstruct some aspect of their lives and their deaths and even what happened after they died,” she continued. “Importantly, we shouldn’t look at a state of collapse as the beginning of a ‘dark age,’ but rather view it as an era that breeds resilience and foments stunning innovation within the population.”
Cells from the eye are inkjet printed for the first time
A group of researchers from the UK have used inkjet printing technology to successfully print cells taken from the eye for the very first time.
The breakthrough, which has been detailed in a paper published today, 18 December, in IOP Publishing’s journal Biofabrication, could lead to the production of artificial tissue grafts made from the variety of cells found in the human retina and may aid in the search to cure blindness.
At the moment the results are preliminary and provide proof-of-principle that an inkjet printer can be used to print two types of cells from the retina of adult rats―ganglion cells and glial cells. This is the first time the technology has been used successfully to print mature central nervous system cells and the results showed that printed cells remained healthy and retained their ability to survive and grow in culture.
Co-authors of the study Professor Keith Martin and Dr Barbara Lorber, from the John van Geest Centre for Brain Repair, University of Cambridge, said: “The loss of nerve cells in the retina is a feature of many blinding eye diseases. The retina is an exquisitely organised structure where the precise arrangement of cells in relation to one another is critical for effective visual function”.
“Our study has shown, for the first time, that cells derived from the mature central nervous system, the eye, can be printed using a piezoelectric inkjet printer. Although our results are preliminary and much more work is still required, the aim is to develop this technology for use in retinal repair in the future.”
The ability to arrange cells into highly defined patterns and structures has recently elevated the use of 3D printing in the biomedical sciences to create cell-based structures for use in regenerative medicine.
In their study, the researchers used a piezoelectric inkjet printer device that ejected the cells through a sub-millimetre diameter nozzle when a specific electrical pulse was applied. They also used high speed video technology to record the printing process with high resolution and optimised their procedures accordingly.
“In order for a fluid to print well from an inkjet print head, its properties, such as viscosity and surface tension, need to conform to a fairly narrow range of values. Adding cells to the fluid complicates its properties significantly,” commented Dr Wen-Kai Hsiao, another member of the team based at the Inkjet Research Centre in Cambridge.
Once printed, a number of tests were performed on each type of cell to see how many of the cells survived the process and how it affected their ability to survive and grow.
The cells derived from the retina of the rats were retinal ganglion cells, which transmit information from the eye to certain parts of the brain, and glial cells, which provide support and protection for neurons.
“We plan to extend this study to print other cells of the retina and to investigate if light-sensitive photoreceptors can be successfully printed using inkjet technology. In addition, we would like to further develop our printing process to be suitable for commercial, multi-nozzle print heads,” Professor Martin concluded.
Human Stem Cells Predict Efficacy of Alzheimer Drugs
Researchers from the University of Bonn use reprogrammed patient neurons for drug testing
Why do certain Alzheimer medications work in animal models but not in clinical trials in humans? A research team from the University of Bonn and the biomedical enterprise LIFE & BRAIN GmbH has been able to show that results of established test methods with animal models and cell lines used up until now can hardly be translated to the processes in the human brain. Drug testing should therefore be conducted with human nerve cells, conclude the scientists. The results are published by Cell Press in the journal “Stem Cell Reports”.
In the brains of Alzheimer patients, deposits form that consist essentially of beta-amyloid and are harmful to nerve cells. Scientists are therefore searching for pharmaceutical compounds that prevent the formation of these dangerous aggregates. In animal models, certain non-steroidal anti-inflammatory drugs (NSAIDs) were found to a reduced formation of harmful beta-amyloid variants. Yet, in subsequent clinical studies, these NSAIDs failed to elicit any beneficial effects.
"The reasons for these negative results have remained unclear for a long time", says Prof. Dr. Oliver Brüstle, Director of the Institute for Reconstructive Neurobiology of the University of Bonn and CEO of LIFE & BRAIN GmbH. "Remarkably, these compounds were never tested directly on the actual target cells – the human neuron", adds lead author Dr. Jerome Mertens of Prof. Brüstle’s team, who now works at the Laboratory of Genetics in La Jolla (USA). This is because, so far, living human neurons have been extremely difficult to obtain. However, with the recent advances in stem cell research it has become possible to derive limitless numbers of brain cells from a small skin biopsy or other adult cell types.
Scientists transform skin cells into nerve cells
Now a research team from the Institute for Reconstructive Neurobiology and the Department of Neurology of the Bonn University Medical Center together with colleagues from the LIFE & BRAIN GmbH and the University of Leuven (Belgium) has obtained such nerve cells from humans. The researchers used skin cells from two patients with a familial form of Alzheimer’s Disease to produce so-called induced pluripotent stem cells (iPS cells), by reprogramming the body’s cells into a quasi-embryonic stage. They then transformed the resulting so-called “jack-of-all-trades cells” into nerve cells.
Using these human neurons, the scientists tested several compounds in the group of non-steroidal anti-inflammatory drugs. As control, the researchers used nerve cells they had obtained from iPS cells of donors who did not have the disease. Both in the nerve cells obtained from the Alzheimer patients and in the control cells, the NSAIDs that had previously tested positive in the animal models and cell lines typically used for drug screening had practically no effect: The values for the harmful beta-amyloid variants that form the feared aggregates in the brain remained unaffected when the cells were treated with clinically relevant dosages of these compounds.
Metabolic processes in animal models differ from humans
"In order to predict the efficacy of Alzheimer drugs, such tests have to be performed directly on the affected human nerve cells", concludes Prof. Brüstle’s colleague Dr. Philipp Koch, who led the study. Why do NSAIDs decrease the risk of aggregate formation in animal experiments and cell lines but not in human neurons? The scientists explain this with differences in metabolic processes between these different cell types. "The results are simply not transferable", says Dr. Koch.
The scientists now hope that in the future, testing of potential drugs for the treatment of Alzheimer’s disease will be increasingly conducted using neurons obtained from iPS cells of patients. “The development of a single drug takes an average of ten years”, says Prof. Brüstle. “By using patient-specific nerve cells as a test system, investments by pharmaceutical companies and the tedious search for urgently needed Alzheimer medications could be greatly streamlined”.
(Source: www3.uni-bonn.de)
Alzheimer’s drug discovery: Looking under the right ROCK
A discovery by Emory Alzheimer’s Disease Research Center and Scripps Research Institute scientists could lead to drugs that slow Alzheimer’s disease progression.
A straightforward drug strategy against Alzheimer’s is to turn down the brain’s production of beta-amyloid, the key component of the disease’s characteristic plaques. A toxic fragment of a protein found in healthy brains, beta-amyloid accumulates in the brains of people affected by the disease.
The enzyme that determines how much beta-amyloid brain cells generate is called BACE (beta-secretase or beta-site APP cleaving enzyme). Yet finding drugs that inhibit that elusive enzyme has been far from straightforward.
Now researchers have identified a way to shut down production of beta-amyloid by diverting BACE to a different part of the cell and inhibiting its activity. The results were published this week in Journal of Neuroscience.
"This is an indirect but highly effective way of blocking BACE, which controls the chokepoint step in beta-amyloid production," says lead author Jeremy Herskowitz, PhD, instructor in neurology at Emory’s Alzheimer’s Disease Research Center.
"Jeremy has found a promising approach toward reducing beta-amyloid production and potentially modifying Alzheimer’s disease progression, something for which there is immense need," says senior author James Lah, MD, PhD, associate professor of neurology at Emory University School of Medicine and director of the Cognitive Neurology program. "Drugs that reduce beta-amyloid production would probably be mostly preventive. However, since amyloid-beta is toxic, such drugs could have some immediate effect on cognitive impairment."
In the paper, Herskowitz and his colleagues demonstrate that a specific inhibitor of the enzyme ROCK2 can cut beta-amyloid production in brain cells by more than 75 percent. Co-author Yangbo Feng, PhD, associate director of medicinal chemistry at Scripps Research Institute in Florida, previously discovered the ROCK2 inhibitor, called SR3677.
Alzheimer’s researchers were already interested in ROCK2 and a related enzyme, ROCK1, because of a connection with NSAIDs (non-steroid anti-inflammatory drugs) such as ibuprofen. Some NSAIDS can inhibit production of a particularly toxic form of beta-amyloid, and scientists believed NSAIDs were exerting their effects through the ROCKs.
Herskowitz first showed that in cultured cells, “knocking down” the ROCK2 gene reduced beta-amyloid production, but knocking down ROCK1 had the opposite effect.
"This says that anytime you’re hitting both ROCKs at once, the effects cancel each other out," he says.
The known drugs that affect the ROCKs seemed to affect both and thus have diminished effects. In contrast, SR3677 inhibits ROCK2 much more effectively than ROCK1, and it offered a way around the obstacle. Herskowitz found that by inhibiting ROCK2, SR3677 diverts BACE to a different part of the cell, where it is less likely to act on beta-amyloid’s parent protein.
He and ADRC colleagues found that ROCK2 levels are higher than usual in tissue samples from brains of patients with Alzheimer’s, including those with mild cognitive impairment, thought to be a precursor stage of the disease.
"There is plenty of ROCK2 in the brain, and its levels are elevated in Alzheimer’s patients, indicating that it’s an excellent drug target," Herskowitz says. "We are eager to pursue more extensive studies of this strategy in animal models of Alzheimer’s."
SR3677 can substantially inhibit beta-amyloid production in an animal model of Alzheimer’s, but so far, this effect has been observed when the drug is injected directly into the brain. More studies are required to learn if SR3677 or related drugs can pass the blood-brain barrier and thus be given by injection or orally, and what side effects could appear. ROCK inhibitors are also being investigated for treating other conditions such as glaucoma, hypertension and multiple sclerosis.
(Source: news.emory.edu)
How Mosquitoes Are Drawn to Human Skin and Breath
Female mosquitoes, which can transmit deadly diseases like malaria, dengue fever, West Nile virus and filariasis, are attracted to us by smelling the carbon dioxide we exhale, being capable of tracking us down even from a distance. But once they get close to us, they often steer away toward exposed areas such as ankles and feet, being drawn there by skin odors.
Why does the mosquito change its track and fly towards skin? How does it detect our skin? What are the odors from skin that it detects? And can we block the mosquito skin odor sensors and reduce attractiveness?
Recent research done by scientists at the University of California, Riverside can now help address these questions. They report on Dec. 5 in the journal Cell that the very receptors in the mosquito’s maxillary palp that detect carbon dioxide are ones that detect skin odors as well, thus explaining why mosquitoes are attracted to skin odor — smelly socks, worn clothes, bedding — even in the absence of CO2.
“It was a real surprise when we found that the mosquito’s CO2 receptor neuron, designated cpA, is an extremely sensitive detector of several skin odorants as well, and is, in fact, far more sensitive to some of these odor molecules as compared to CO2,” said Anandasankar Ray, an associate professor in the Department of Entomology and the project’s principal investigator. “For many years we had primarily focused on the complex antennae of mosquitoes for our search for human-skin odor receptors, and ignored the simpler maxillary palp organs.”
Until now, which mosquito olfactory neurons were required for attraction to skin odor remained a mystery. The new finding — that the CO2-sensitive olfactory neuron is also a sensitive detector of human skin — is critical not only for understanding the basis of the mosquito’s host attraction and host preference, but also because it identifies this dual receptor of CO2 and skin-odorants as a key target that could be useful to disrupt host-seeking behavior and thus aid in the control of disease transmission.
To test whether cpA activation by human odor is important for attraction, the researchers devised a novel chemical-based strategy to shut down the activity of cpA in Aedes aegypti, the dengue-spreading mosquito. They then tested the mosquito’s behavior on human foot odor — specifically, on a dish of foot odor-laden beads placed in an experimental wind tunnel — and found the mosquito’s attraction to the odor was greatly reduced.
Next, using a chemical computational method they developed, the researchers screened nearly half a million compounds and identified thousands of predicted ligands. They then short-listed 138 compounds based on desirable characteristics such as smell, safety, cost and whether these occurred naturally. Several compounds either inhibited or activated cpA neurons of which nearly 85 percent were already approved for use as flavor, fragrance or cosmetic agents. Better still, several were pleasant-smelling, such as minty, raspberry, chocolate, etc., increasing their value for practical use in mosquito control.
Confident that they were on the right track, the researchers then zeroed in on two compounds: ethyl pyruvate, a fruity-scented cpA inhibitor approved as a flavor agent in food; and cyclopentanone, a minty-smelling cpA activator approved as a flavor and fragrance agent. By inhibiting the cpA neuron, ethyl pyruvate was found in their experiments to substantially reduce the mosquito’s attraction towards a human arm. By activating the cpA neuron, cyclopentanone served as a powerful lure, like CO2, attracting mosquitoes to a trap.
“Such compounds can play a significant role in the control of mosquito-borne diseases and open up very realistic possibilities of developing ways to use simple, natural, affordable and pleasant odors to prevent mosquitoes from finding humans,” Ray said. “Odors that block this dual-receptor for CO2 and skin odor can be used as a way to mask us from mosquitoes. On the other hand, odors that can act as attractants can be used to lure mosquitoes away from us into traps. These potentially affordable ‘mask’ and ‘pull’ strategies could be used in a complementary manner, offering an ideal solution and much needed relief to people in Africa, Asia and South America — indeed wherever mosquito-borne diseases are endemic. Further, these compounds could be developed into products that protect not just one individual at a time but larger areas, and need not have to be directly applied on the skin.”
Currently, CO2 is the primary lure in mosquito traps. Generating CO2 requires burning fuel, evaporating dry ice, releasing compressed gas or fermentation of sugar — all of which is expensive, cumbersome, and impractical for use in developing countries. Compounds identified in this study, like cyclopentanone, offer a safe, affordable and convenient alternative that can finally work with surveillance and control traps.
Polymer Foam Expands Potential to Treat Aneurysms
Thirty thousand Americans suffer severe neurological damage or death from brain aneurysms each year and the existing treatments eventually fail in nearly half of patients. Currently, these “bubbles” in the blood vessel are either clamped off, which requires invasive brain surgery, or filled with platinum coils to induce clotting in the aneurysm. Both treatments, although somewhat effective, can have subsequent problems, including inflammation, incomplete healing, and the development of secondary aneurysms adjacent to the initial site. These complications result in approximately 40 percent of patients needing additional treatment to attempt to re-repair the aneurysm.
NIBIB-funded researchers in Texas A&M’s bioengineering department are moving rapidly to provide a better treatment for this serious disorder. The group specializes in using the unique properties of foam shape memory polymers (SMPs) to solve clinical conditions lacking satisfactory treatments.
The group, led by Associate Professor Duncan Maitland, is using SMPs in a pig model of brain aneurysm to develop a minimally-invasive procedure that fills and stabilizes the aneurysm. Because the system induces only minimal inflammation, it successfully allows natural healing of the border between the aneurysm and the blood vessel. As reported in the May 22 issue of the Journal of Biomedical Materials Research, partial healing was observed at 30 days post-procedure and almost complete healing had occurred at 90 days in the pig model.
How it Works
Two of the properties of SMP are critical to the success seen in the animal experiments:
- the foam’s ability to be compressed into a very thin sheath and then induced to expand to 100 times its compressed volume when heated, and
- its rigid, yet porous structure when fully expanded.
The rigid uniform structure of the expanded foam is a significant improvement over the current practice of filling an aneurysm with a platinum coil. Because a coil is threaded into the aneurysm until it fills the space, pressure is exerted on the aneurysm during the process, which can damage the vessel wall. In addition, the platinum coils do not uniformly fill the space, leaving large gaps that can allow shifting of the coils as well as the formation of unstable, large clots. The platinum coil approach can also result in inflammation which destabilizes the aneurysm, resulting in incomplete healing and failure to completely wall-off from the blood vessel.
The minimally-invasive procedure involves inserting the slim, compressed foam into the aneurysm using a microcatheter. The microcatheter is inserted into an artery through a small cut in the groin and then threaded through the blood vessels to the location of the aneurysm in the brain. Once in position, a laser optical fiber heats the foam to induce expansion and complete filling of the fragile pouch of the aneurysm. In contrast to the platinum coils currently in use, the foam exerts a firm, uniform pressure on the walls of the aneurysm, which reduces chances of rupture.
The foam contains tiny compartments that result in the development of a matrix of blood clots that further stabilize the structure. The investigators found that unlike the aneurysms filled with metal coils, the foam structure produced little inflammation and allowed natural healing, defined by the growth of new cells at the border between the foam and the wall of the damaged blood vessel.
Making a Difference through Innovative Technologies
Dr. Maitland describes his work, broadly, as developing technologies to solve clinical problems that lack satisfactory solutions. He has formed a company called Shape Memory Therapeutics to assist with moving the encouraging results obtained with the SMP system from animal models into testing and, potentially, eventual use in humans. Maitland’s desire to make a difference is clear. “There are people walking around with aneurysms that are untreatable. My hope is to develop a game-changing therapy that reduces the risk of aneurysm ruptures, increases patient safety, and has a real impact on human health care.”
Study looks at better prediction for epileptic seizures through adaptive learning approach
A UT Arlington assistant engineering professor has developed a computational model that can more accurately predict when an epileptic seizure will occur next based on the patient’s personalized medical information.
The research conducted by Shouyi Wang, an assistant professor in the Department of Industrial and Manufacturing Systems Engineering, has been in the paper “Online Seizure Prediction Using an Adaptive Learning Approach” in IEEE Transactions on Knowledge and Data Engineering.
Wang’s model analyzes electroencephalography, or EEG, readings from an individual, to predict future seizures. Early warnings could lead a patient to use medicine to combat an oncoming seizure, he said.
“The challenge with seizure prediction has been that every epileptic is different. Some patients suffer several seizures a day. Others will go several years without experiencing a seizure,” Wang said. “But if we use the EEG readings to build a personalized data profile, we’re better able to understand what’s happening to that person.”
Epilepsy is one of the most common neurological disorders, characterized by recurrent seizures. Epilepsy and seizures affect nearly 3 million Americans at an estimated annual cost of $17.6 billion in direct and indirect costs, according to the national Epilepsy Foundation, About 10 percent of the American population will experience a seizure in their lifetime, the agency says.
Wang teamed with Wanpracha Art Chaovalitwongse of the University of Washington and Stephen Wong of the Rutgers Robert Wood Johnson Medical School for the research.
Wang said early indications are that the new computational model could provide 70 percent accuracy or better and give a prediction horizon of about 30 minutes before the actual seizure would occur.
The current model collects data through a cap embedded with EEG wires. Wang’s team is working to develop a less obtrusive EEG cap that will record and transmit readings to a box for easy data download or transmission.
Victoria Chen, professor and chairwoman of the Industrial and Manufacturing Systems Engineering Department, said Wang’s work in the area of bioinformatics offers hope for the many people who suffer from epilepsy.
“This computational model might be used to predict other life-threatening episodes of diseases,” Chen said.
Wang said his model builds upon an adaptive learning framework and is capable of achieving more and more accurate prediction performance for each individual patientby collecting more and more personalized medical data.
“As a society, we’ve gotten really good at looking at the big picture,” Wang said. “We can tell you the likelihood of suffering a heart attack if you’re over a certain age, of a certain weight and if you smoke. But we have only started to personalize that data for individuals who are all different.”
Clinical Trial Brings Positive Results for Tinnitus Sufferers
UT Dallas researchers have demonstrated that treating tinnitus, or ringing in the ears, using vagus nerve stimulation-tone therapy is safe and brought significant improvement to some of the participants in a small clinical trial.
Drs. Sven Vanneste and Michael Kilgard of the School of Behavioral and Brain Sciences used a new method pairing vagus nerve stimulation (VNS) with auditory tones to alleviate the symptoms of chronic tinnitus. Their results were published on Nov. 20 in the journal Neuromodulation: Technology at the Neural Interface.
VNS is an FDA-approved method for treating various illnesses, including depression and epilepsy. It involves sending a mild electric pulse through the vagus nerve, which relays information about the state of the body to the brain.
“The primary goal of the study was to evaluate safety of VNS-tone therapy in tinnitus patients,” Vanneste said. “VNS-tone therapy was expected to be safe because it requires less than 1 percent of the VNS approved by the FDA for the treatment of intractable epilepsy and depression. There were no significant adverse events in our study.”
According to Vanneste, more than 12 million Americans have tinnitus severe enough to seek medical attention, of which 2 million are so disabled that they cannot function normally. He said there has been no consistently effective treatment.
The study, which took place in Antwerp, Belgium, involved implanting 10 tinnitus sufferers with a stimulation electrode directly on the vagus nerve. They received 2 ½ hours of daily treatment for 20 days. The participants had lived with tinnitus for at least a year prior to participating in the study, and showed no benefit from previous audiological, drug or neuromodulation treatments. Electrical pulses were generated from an external device for this study, but future work could involve using internal generators, eliminating the need for clinical visits.
Half of the participants demonstrated large decreases in their tinnitus symptoms, with three of them showing a 44-percent reduction in the impact of tinnitus on their daily lives. Four people demonstrated clinically meaningful reductions in the perceived loudness of their tinnitus by 26 decibels.
Five participants, all of whom were on medications for other problems, did not show significant changes. However, the four participants who benefited from the therapy were not using any medications. The report attributes drug interactions as blocking the effects of the VNS-tone therapy.
“In all, four of the 10 patients showed relevant decreases on tinnitus questionnaires and audiological measures,” Vanneste said. “The observation that these improvements were stable for more than two months after the end of the one month therapy is encouraging.”
Surgeons Find New Method to Reduce Risk of Blood Clots During Brain Traumas
Researchers from the University of Missouri School of Medicine have found that a new protocol that uses preventive blood-thinning medication in the treatment of patients with traumatic brain injuries reduces the risk of patients developing life-threatening blood clots without increasing the risk of bleeding inside the brain.
According to the Centers for Disease Control and Prevention, at least 1.7 million traumatic brain injuries occur each year. One of the most common complications associated with traumatic brain injuries is the risk of dangerous blood clots that can form in the circulatory system elsewhere in the body. For patients with traumatic injuries, the body forms blood clots which can break loose and travel to the lungs or other areas, causing dangerous complications.
"Our study found that treating traumatic brain-injured patients with an anticoagulant, or blood-thinning medication, is safe and decreases the risk of these dangerous clots," said N. Scott Litofsky, MD, chief of the MU School of Medicine’s Division of Neurological Surgery and director of neuro-oncology and radiosurgery at MU Health Care. "We found that patients treated with preventive blood thinners had a decreased risk of deep-vein blood clots and no increased risk of intracranial hemorrhaging."
In May 2009, Litofsky, along with study co-author Stephen Barnes, MD, acute care surgeon and chief of the MU Division of Acute Care Surgery, created a new protocol for treating head trauma patients in University Hospital’s Frank L. Mitchell Jr., M.D., Trauma Center using blood-thinning medications.
"One of the main challenges in treating patients with traumatic brain injuries is balancing the risk of intracranial bleeding with the risk of blood clots formed elsewhere in the body," Litofsky said.
In the study, the researchers compared the outcomes of 107 patients with traumatic brain injuries who were treated before the new protocol was put into place with the outcomes of 129 patients who were treated with the blood-thinning medication. Among the patients who did not receive blood thinners, six experienced deep-venous clotting, compared with zero instances of the condition in patients who received the medication. Among the patients who did not receive blood thinners, three patients experienced increased bleeding in the brain, compared with one patient who received the medication.
"Based on our results, we will continue to follow the new protocol in our trauma center, and we believe that other trauma centers would benefit from adopting a similar protocol in their practice," Litofsky said. "If we look at this issue across the country, we should hopefully see this complication occurring less often in brain-injured patients."
The study, “Safety and Efficacy of Early Thromboembolism Chemoprophylaxis After Intracranial Hemorrhage from Traumatic Brain Injury,” was published online Sept. 20 by the Journal of Neurosurgery, the journal for the American Association of Neurological Surgeons.
(Source: medicine.missouri.edu)
Statin Use Not Linked to a Decline in Cognitive Function
Based on the largest comprehensive systematic review to date, researchers at the Perelman School of Medicine at the University of Pennsylvania concluded that available evidence does not support an association between statins and memory loss or dementia. The new study, a collaborative effort between faculty in Penn Medicine’s Preventive Cardiovascular Program, the Penn Memory Center, and the Penn Center for Evidence-Based Practice, will be published in Annals of Internal Medicine.
“Statins are prescribed to approximately 30 million people in the United States, and these numbers may increase as a result of the national cholesterol guidelines recently released,” said senior study author Emil deGoma, MD, assistant professor of Medicine and medical director of the Preventive Cardiovascular Program at Penn. “A wealth of data supports a benefit of these cholesterol-lowering medications among individuals at risk for cardiovascular disease in terms of a reduction in the risk of heart attack and stroke; however, potential side effects of statins are less well understood. In February 2012, largely based on anecdotal reports, the U.S. Food and Drug Administration (FDA) issued a safety statement warning patients of possible adverse cognitive effects associated with statin use. Many concerned patients have asked if there is a relationship between statins and memory problems. Their concerns, along with the FDA statement, prompted us to pursue a rigorous analysis of all available evidence to better answer the question – are statins associated with changes in cognition?”
The research team conducted a systematic review of the published literature and identified 57 statin studies reporting measures of cognitive function. Dr. deGoma and colleagues found no evidence of an increased risk of dementia with statin therapy. In fact, in cohort studies, statin users had a 13 percent lower risk of dementia, a 21 percent lower risk of Alzheimer’s disease, and a 34 percent lower risk of mild cognitive impairment compared to people who did not take statins.
Most importantly, cognitive test scores were not adversely affected by statin treatment in randomized controlled trials. In these trials, roughly half of the study participants received statins and the other half received placebo. All study participants underwent formal testing of memory and other cognitive domains through tests such as the ability to recall a set of numbers. The analysis of 155 cognitive tests spanning eight categories of cognitive function, including 26 tests of memory, revealed no differences between study participants treated with statins and those provided placebo.
The research team additionally performed an analysis of the FDA post-marketing surveillance databases and found no difference in the frequency of cognitive adverse event reports between statins and two commonly prescribed cardiovascular medications that have not been associated with cognitive impairment, namely, clopidogrel and losartan.
“Overall, these findings are quite reassuring. I wouldn’t let concerns about adverse effects on cognition influence the decision to start a statin in patients suffering from atherosclerotic disease or at risk for cardiovascular disease. I also wouldn’t jump to the conclusion that statins are the culprit when an individual who is taking a statin describes forgetfulness. We may be doing more harm than good if we withhold or stop statins – medications proven to reduce the risk of heart attack and stroke – due to fears that statins might possibly cause memory loss,” said Dr. deGoma.
The team acknowledges that while their analysis is reassuring, large, high-quality randomized controlled trials are needed to confirm their findings.
“For many of the cognitive outcomes that we examined, the identified studies were small, were at risk for bias, used varying diagnostic tests to assess cognitive domains, and did not include patients on high-dose statins, which is important given the increasing use of high-dose statins for secondary prevention,” noted study co-author Craig Umscheid, MD, MSCE, assistant professor of Medicine and Epidemiology and director of the Penn Center for Evidence-based Practice. “Thus, additional trials addressing these limitations would strengthen our conclusions. Despite this, the totality of the evidence does reassure us that there’s unlikely to be a significant link between statins and cognitive impairment.”