Links for Keyword: Stroke
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It's a scenario straight out of Gray's Anatomy – a paramedic or doctor plops a mask over the face of a person struggling to breathe and begins dispensing pure oxygen. Yet growing research suggests that inhaling straight oxygen can actually harm the brain. For the first time, a new UCLA brain-imaging study reveals why. Published in the May 22 edition of Public Library of Science (PLoS) Medicine, the findings fly in the face of national guidelines for medical practice and recommend a new approach adding carbon dioxide to the gas mix to preserve brain function in patients. "For decades, the medical community has championed 100 percent oxygen as the gold standard for resuscitation. But no one has reported what happens inside our brains when we inhale pure oxygen," explained Ronald Harper, distinguished professor of neurobiology at the David Geffen School of Medicine at UCLA. "What we discovered adds to a compelling body of evidence for modifying a widely practiced standard of care in the United States." Harper's team used functional magnetic resonance imaging (fMRI) to capture detailed pictures of what occurs inside the human brain during two different breathing scenarios. The technique detects subtle increases in blood flow triggered by the activation of different parts of the brain, causing these regions to glow or "light up" on the color scan.
Gaia Vince Methamphetamine may protect the brain after a stroke, according to new research in rats and gerbils. The illicit street drug – also known as speed – helped reduce brain damage when used up to 16 hours after stroke, potentially widening the window of opportunity for drug intervention. Researchers induced strokes in gerbils, causing them to become twice as active and agitated as normal gerbils. But when the animals were given a low dose of methamphetamine up to 16 hours after the event, the animals became calmer. Dissection later showed that the neurons of the gerbils given methamphetamine were as intact as in animals that had not suffered stroke. “Methamphetamine is a drug that has been shown to exacerbate stroke damage when administered before a stroke, but we have seen roughly 80% to 90% protection of neurons when administered after a stroke,” says Dave Poulsen, who led the research at the University of Montana in the US. The team also looked at slices of rat brain taken from the hippocampus – a region involved in memory and learning – which they kept in a nutritious culture for nine days. The slices were then deprived of glucose and oxygen for 90 minutes to mimic the conditions of a stroke. © Copyright Reed Business Information Ltd
Related chapters from BP7e: Chapter 19: Language and Hemispheric Asymmetry; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 15: Language and Our Divided Brain; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 9466 - Posted: 06.24.2010
NEW BRUNSWICK/PISCATAWAY, N.J. – Engineers at Rutgers, The State University of New Jersey, have modified a popular home video game system to assist stroke patients with hand exercises, producing a technology costing less than $600 that may one day rival systems 10 times as expensive. The Rutgers hand rehabilitation system is an example of virtual rehabilitation, which combines virtual reality – computer-generated interactive visual environments in which users control actions in a lifelike way – with traditional therapy techniques. Virtual rehabilitation gives therapists new tools to do their jobs more effectively and engages patients who may otherwise lack interest or motivation to complete normal exercise regimens. The Rutgers engineers are describing their work at the fifth International Workshop on Virtual Rehabilitation taking place Aug. 29 and Aug. 30 in New York City. “Virtual reality is showing significant promise for promoting faster and more complete rehabilitation, but the cost of many systems is still prohibitive for widespread deployment in outpatient clinics or patients’ homes,” said Grigore Burdea, professor of electrical and computer engineering and a noted inventor of virtual rehabilitation technology. “While it’s essential to keep pursuing breakthrough technologies that will initially be costly, it’s just as important that we find ways to make innovative treatments accessible to the many patients who need them.” © 2006 Rutgers, The State University of New Jersey
Alison Motluk Aspirin prevents cardiovascular events in both women and men – but in different ways, a new meta-study suggests. In women, aspirin reduces strokes, and in men it cuts down on heart attacks. But there are no statistically significant benefits the other way round, according to the analysis. “It appears that women respond differently to a given dose of aspirin than men,” says David Brown, a cardiologist at the Stony Brook School of Medicine in New York, US, and one of the authors. “Everything about the study is telling us that there’s a gender difference and we don’t understand it.” In people who already have cardiovascular disease, the benefits of low-dose aspirin are well-established – in both sexes. Aspirin’s cardiovascular effects are exerted by blocking the synthesis of thromboxane A2, a substance that causes the blood to clot. Even a single 100 milligram dose can be effective. But in people with moderate risk, the picture is less clear. Studies seem to indicate a reduction in coronary events, but most studies included few, if any, women. Brown and colleagues were interested in knowing if moderate-risk women would benefit to the same degree as men. © Copyright Reed Business Information Ltd
Related chapters from BP7e: Chapter 19: Language and Hemispheric Asymmetry; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 15: Language and Our Divided Brain; Chapter 8: Hormones and Sex
Link ID: 8405 - Posted: 06.24.2010
Toni Baker A bi-polar hormone that can contribute to strokes and minimize their damage is emerging as a therapeutic target in the battle against these brain attacks, researchers say. “It costs about $56 billion a year to look after stroke patients, never mind the quality-of-life issues for these patients,” says Dr. Anne M. Dorrance, Medical College of Georgia physiologist and senior author of a review article on the cover of the November issue of Trends in Endocrinology and Metabolism. Despite better management of blood pressure – the number-one risk factor for strokes – stroke incidence is not declining and aging baby boomers likely will cause rates to spike, says Dr. Dorrance. She is among an increasing number of scientists who think the hormone, aldosterone, is part of the problem and blocking it may be part of the solution. Scientific momentum surrounding the hormone secreted by the adrenal gland prompted the journal to ask Dr. Dorrance to write the article, “Aldosterone: Good Guy or Bad Guy in Cerebrovascular Disease.” Copyright 2005 Medical College of Georgia
Related chapters from BP7e: Chapter 19: Language and Hemispheric Asymmetry; Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 15: Language and Our Divided Brain; Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 8238 - Posted: 06.24.2010
St. Paul, Minn. – Looking into our eyes may help doctors predict who is at risk for stroke. A new study found that people with changes in the small blood vessels in their eyes are more likely to later suffer a stroke than people without these signs. The results held true even after researchers took into account traditional risk factors for stroke such as smoking and high blood pressure, according to the study published in the October 11, 2005 issue of Neurology, the scientific journal of the American Academy of Neurology. The study involved 3,654 Australians age 49 and older. Researchers took special photographs of the retina of the eyes of the participants and examined them for changes suggestive of small blood vessel damage, or retinopathy. These small vessel changes can be seen in the early stages of the condition, well before eyesight is affected. “The blood vessels in the eyes share similar anatomical characteristics and other characteristics with the blood vessels in the brain,” said Paul Mitchell, MD, PhD, of the University of Sydney in Australia. “More research needs to be done to confirm these results, but it’s exciting to think that this fairly simple procedure could help us predict whether someone will be more likely to have a stroke several years later.”
Related chapters from BP7e: Chapter 19: Language and Hemispheric Asymmetry; Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 15: Language and Our Divided Brain; Chapter 7: Vision: From Eye to Brain
Link ID: 8017 - Posted: 06.24.2010
La Jolla, Calif. – A research team lead by the Burnham Institute has synthesized and tested a new series of inhibitors that can prevent the type of nerve cell injury and death associated with many neurodegenerative diseases and stroke. The study, led by Stuart Lipton, MD, PhD, professor and director of Burnham's Del E. Webb Center for Neuroscience and Aging Research, is published in the July issue of the Journal of Neuroscience. There is but one medical treatment approved for stroke, the third leading cause of death in the United States: tissue plasminogen activator ("tPA"). tPA must be administered within 3 hours of stroke onset to restore the flow of blood to the brain. Unfortunately, treatment with tPA can also contribute to nerve cell damage. In recent years, medical scientists have begun to understand that tPA activates an entire family of enzymes, called matrix metalloproteinases, that normally regulate how cell structures are held together. Dr. Lipton, together with first author Dr. Zezong Gu, and other colleagues at Burnham, University of Notre Dame, and Wayne State University in Detroit, have found that a molecule called SB-3CT blocks the activity of one member of the metalloproteinase family, called MMP-9. Previous work at Burnham and elsewhere has shown that damage to the brain triggers excessive activity among MMPs, especially MMP-9. The enzymes degrade cell structures, inducing cell death and escalating brain damage in mice. In the current study, the researchers determined the particular mechanism of action for MMP-9. In doing so, they identified a new drug target and, armed with this knowledge, generated a lead therapeutic compound, SB-3CT.
St. Paul, Minn. – A new therapy that uses magnetic pulses to stimulate the brain may improve recovery after a stroke, according to a study published in the May 24 issue of Neurology, the scientific journal of the American Academy of Neurology. The treatment, called repetitive transcranial magnetic stimulation, improved motor function in a small group of people. For the stimulation, an insulated wire coil is placed on the scalp, and a brief electrical current is passed through the coil, creating a magnetic pulse that stimulates the outer part of the brain, called the cortex. The study involved eight people, ages 35 to 63, who had a stroke within the last year and were relearning to use their affected hands. They were compared to six people who had never had a stroke. The stroke patients received three sessions of magnetic stimulation to the side of the brain that had not been affected by the stroke using different parameters, including sham (mock) stimulation. A sham is the application of the procedure excluding the actual treatment being studied and is intended to address the question of a placebo effect. The six healthy participants were tested with the same battery of tests to evaluate the learning effect associated with repeated testing. All of the participants performed tests before and after the stimulations. The tests evaluated the motor function of the hand that was affected by the stroke. For example, reaction time was tested, along with how many finger taps could be performed over a period of time.
In 2001, a massive stroke left Pete Cornelis all but paralyzed – robbing him of his passion for painting, as well as everyday things like walking and eating. "The only thing I could move on my entire body was my two fingers," he recalls. But thanks to his treatment at The Neurological Institute of New York, part of Columbia University Medical Center, followed by years of hard work, perseverance and extensive physical therapy, Cornelis managed to regain almost all of his lost movement. "I was surprised by how much I had to relearn," he ays. But, "it is absolutely possible to retrain you brain, to re-wire it, and have it learn what the old [damaged brain] parts used to do." His brain had to slowly work to compensate for the areas of his brain that were basically dead and could not be revived. When a stroke occurs, blood flow to part of the brain is interrupted when a blood vessel becomes damaged or blocked. The blood normally brings oxygen and nutrients that the brain cells in the immediate area need to survive. Without the blood the brain cells begin to die and stroke victims lose the functions that were controlled by those brain cells. About 80% of all strokes are ischemic, caused by a blood clot that blocks a blood vessel or artery in the brain. The other 20% are caused by a weakened blood vessel that breaks and bleeds into the brain. This is known as hemorrhagic stroke, and is often fatal. Around 600,000 new strokes, or "brain attacks" are reported each year. (C) ScienCentral, 2000-2005.
St. Paul, Minn. – Warning signs of an ischemic stroke may be evident as early as seven days before an attack and require urgent treatment to prevent serious damage to the brain, according to a study of stroke patients published in the March 8, 2005 issue of Neurology, the scientific journal of the American Academy of Neurology. Eighty percent of strokes are ischemic, caused by the narrowing of the large or small arteries of the brain, or by clots that block blood flow to the brain. They are often preceded by a transient ischemic attack (TIA), a “warning stroke” or “mini-stroke” that shows symptoms similar to a stroke, typically lasts less than five minutes, and does not injure the brain. The study examined 2,416 people who had experienced an ischemic stroke. In 549 patients, TIAs were experienced prior to the ischemic stroke and in most cases occurred within the preceding seven days: 17 percent occurring on the day of the stroke, 9 percent on the previous day, and 43 percent at some point during the seven days prior to the stroke.
St. Paul, Minn. – Anger and other negative emotions may be triggers for ischemic stroke, according to a study published in the December 14 issue of Neurology, the scientific journal of the American Academy of Neurology. The study found that people who had strokes were more likely to have experienced anger or negative emotions in the two hours prior to the stroke than at the same time the day before the stroke. They were also more likely to have reacted quickly to a startling event, such as getting out of bed suddenly after hearing a grandchild fall down and cry or standing up from a chair quickly after hearing an unexpected loud noise. The people were also more likely to have experienced anger, negative emotions, or sudden changes in body position in the two hours before the stroke than they were, on average, in the year before the stroke. “We know a lot about risk factors that make people more likely to have a stroke in their lifetime, such as smoking and high blood pressure, but until now we haven’t had any information on what causes a stroke to occur at a particular time,” said study author Silvia Koton, PhD, MOccH, RN, of Tel Aviv University and the Israel Center for Disease Control. “These findings may help us understand how these triggers result in stroke. We can also investigate whether people at a high risk of stroke can make behavior changes. The possibility of preventive medications to lessen the risk of stroke among specific high-risk groups might also be studied.”
Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 19: Language and Hemispheric Asymmetry
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 15: Language and Our Divided Brain
Link ID: 6610 - Posted: 06.24.2010
CHICAGO – People suffering from paralysis due to stroke or traumatic brain injury may be able to reprogram their brains to improve motor skills and to control artificial limbs, according to a study presented today at the annual meeting of the Radiological Society of North America (RSNA). Using functional magnetic resonance imaging (fMRI) and a "cyberglove" to record brain changes during motor activities, researchers demonstrated that people can learn to remap, or redirect, motor commands. This is an important step in stroke recovery and in training strategies for brain-machine interfaces--conduits between the brain and artificial limbs. "For stroke patients and others who have a brain deficit, coordinating what they see with body movement is very difficult," said the study's lead author Kristine Mosier, D.M.D., Ph.D., assistant professor of radiology at Indiana University in Indianapolis. "The brain must remap or relearn the process of matching visual input with sensory input. Our study demonstrated that individuals can learn to remap motor commands." When neurons--the primary cells of the nervous system that make all thought, feeling and movement possible--are damaged by a stroke or brain injury, other neurons take over for them. But until now, scientists weren't sure which neurons compensated for damaged neurons, or how the brain cells learned their new jobs.
SAN FRANCISCO – Researchers are conducting a groundbreaking new study that may help stroke patients regain greater use of their hands or arms through treatment with electrical stimulation. Preliminary results of the feasibility study that precedes this new study have shown that the use of electrical stimulation, called motor cortex stimulation, may be both safe and effective, according to Robert Levy, M.D., Ph.D., a neurosurgeon at Northwestern Memorial Hospital in Chicago. Dr. Levy presented this feasibility trial data at the Congress of Neurological Surgeons Wednesday in San Francisco. The trial showed that study participants – stroke survivors suffering impaired hand or arm movement – who underwent physical rehabilitation accompanied by motor cortex stimulation showed greater improvement than participants who received physical rehabilitation alone. Twenty-four subjects participated in the feasibility study, 12 in the electrical stimulation group and 12 in the control group. "Participants in the electrical stimulation group experienced meaningful motor recovery gains," Dr. Levy says. "It is our hope that by stimulating the surface of the brain we can permanently reverse paralysis and rekindle patients' function, returning them to their normal lifestyle," says Dr. Levy, who is a professor at the Feinberg School of Medicine at Northwestern University and who is leading the study at Northwestern Memorial, which is being conducted in tandem with the Rehabilitation Institute of Chicago. "Unfortunately, when patients have had a stroke, there is not much we can currently offer beyond physical rehabilitation to improve their motor functions."
Related chapters from BP7e: Chapter 19: Language and Hemispheric Asymmetry; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 15: Language and Our Divided Brain; Chapter 5: The Sensorimotor System
Link ID: 6285 - Posted: 06.24.2010
St. Paul, Minn. – A recent analysis of tamoxifen studies completed since 1980 revealed an increased risk of stroke in women who were randomized to tamoxifen versus placebo or other therapies. Details of the analysis and the researchers’ conclusions are reported in the October 12 issue of Neurology, the scientific journal of the American Academy of Neurology. More than 250,000 U.S. women are diagnosed with breast cancer each year. Breast cancer accounts for nearly one in three cancers diagnosed in the U.S. and is the second leading cause of death for women. Fortunately, 90 percent of breast cancers are now diagnosed at localized and regional stages, for which five-year survival rates are 97 percent and 79 percent, respectively. Tamoxifen, a medication in pill form that interferes with the activity of estrogen, has been used for more than 20 years to treat patients with advanced breast cancer. It is used as adjuvant, or additional, therapy following primary treatment for early stage breast cancer. In women at high risk of developing breast cancer, tamoxifen reduces the chance of developing the disease. In addition to its effects on breast cancer, the benefits of tamoxifen include increased bone mineral density, reduced risk of hip fractures, and lower levels of cholesterol. While tamoxifen is known to increase the risk of blood clotting in women with cancer, its relationship to stroke risk has been unclear.
Related chapters from BP7e: Chapter 19: Language and Hemispheric Asymmetry; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 15: Language and Our Divided Brain; Chapter 8: Hormones and Sex
Link ID: 6231 - Posted: 06.24.2010
ST. LOUIS -- Testosterone -– the hormone responsible for a man's sex drive -– may help him recover from a stroke, according to preliminary animal research at Saint Louis University. Researchers will present their findings at the annual meeting of the American Neurological Association in October. "It looks like testosterone speeds up the recovery from a stroke," said Yi Pan, M.D., Ph.D., assistant professor of neurology at Saint Louis University School of Medicine and principal investigator on the study. "While the results are encouraging, this is still very preliminary and we need to do more research." The scientists compared two groups of castrated rats that had suffered strokes. Half received testosterone and half a placebo. The rats that received testosterone showed significant improvement in neurological deficits while those in the control group did not. Based on the promising findings, plans are on the drawing board to test whether testosterone helps people recover from strokes, said Aninda B. Acharya, M.D., assistant professor of neurology at Saint Louis University School of Medicine and a researcher on the project.
Related chapters from BP7e: Chapter 5: Hormones and the Brain; Chapter 19: Language and Hemispheric Asymmetry
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 15: Language and Our Divided Brain
Link ID: 6200 - Posted: 06.24.2010
St. Paul, Minn. – As many as 65 percent of stroke patients are likely to be treated with antihypertensive medications during the first four days of hospitalization, despite current guidelines of the American Stoke Association that recommend against treating all but the most severe cases of hypertension during the first few days following a stroke. A recent retrospective study found that nearly all stroke patients who were being treated for hypertension prior to admission had their medication regimens continued or intensified, and a third who were not taking medications for hypertension had antihypertension treatment initiated during the hospitalization. Study details are published in the July 27 issue of Neurology. Hypertension (high blood pressure) is common at the time of an ischemic stroke and is believed to be the body’s response that maintains adequate blood flow to the area immediately around the stroke site. Lowering elevated blood pressure through medication, while an appropriate measure in stroke prevention, can result in the extension and worsening of acute stroke symptoms, and has even been shown to result in worse short- and long-term outcomes. The dangers of antihypertensive therapy in the setting of acute ischemic stroke have been recognized for some time. Despite active efforts to promote clinical guidelines, first established in 1994, little is known about how often, and under what circumstances, antihypertensive agents are used in the treatment of patients with acute ischemic stroke. “We sought to determine whether the use of antihypertensive agents was consistent with guidelines, and if such use placed patients at further risk of negative outcomes,” noted study author Peter Lindenauer, MD, MSc, of Baystate Medical Center and Tufts University School of Medicine, Springfield.
St. Paul, MN – Boys are 28 percent more likely than girls to have a stroke, and black children are more than twice as likely to have a stroke as other ethnic groups, according to a study in the July 22 issue of Neurology, the scientific journal of the American Academy of Neurology. Researchers identified 2,278 first admissions for childhood stroke in a 10-year period in California by examining a statewide hospital discharge database. Children were one month through 19 years of age and were classified by their parent or guardian as white, black, Hispanic, Asian or other. Boys made up 51 percent of the population, and girls made up 49 percent. Ischemic stroke (the most common type of stroke, resulting from blocked arteries) accounted for 51 percent of the cases. Hemorrhagic stroke accounted for the rest, and was broken down into intracerebral hemorrhage (vessels bleed into the brain) and subarachnoid hemorrhage (abnormal vessels rupture near the membrane surrounding the brain). The annual stroke incidence rate was found to be 2.3 strokes per 100,000 children.
WEST LAFAYETTE, Ind. – Stroke victims may retain more motor coordination than previously thought, according to research led by Purdue University. The findings challenge current understanding of brain function and open new possibilities for aiding the physically challenged. The research team, which included faculty from Purdue and University of California-Berkeley, was led by Purdue professor Howard Zelaznik. The team found that the cerebellum may not be as fully responsible for the timing of "continuous" motions, such as drawing circles repeatedly on paper, as it is for "discontinuous" motions that have a more start-stop nature, such as tapping your finger rhythmically on a table. Patients with cerebellum damage who participated in the study had difficulty tapping a steady beat, but no such trouble with drawing circles in rhythm. The study indicates that stroke victims may retain some motor skills thought to have been lost to cerebellar damage.
ST. PAUL, MN - – Many of the 1.1 million heart attacks and 731,000 strokes that occur each year in the United States might be prevented by controlling risk factors. Among those with a history of heart disease or stroke, African Americans could possibly benefit most from a greater degree of awareness and control of risk factors, as they are significantly more likely to have a higher risk factor profile than many other groups. According to a study published in the January 14 issue of Neurology, the scientific journal of the American Academy of Neurology, inadequate rates of awareness and control of risk factors remain prevalent among African American stroke patients. Risk factors studied include hypertension, diabetes, cigarette smoking, excessive alcohol use, and high cholesterol. “We sought to determine rates of awareness, treatment and control of major risk factors among patients at the time of enrollment into the African American Antiplatelet Stroke Prevention Study (AAASPS),” said study author Sean Ruland, DO, of Rush University in Chicago. The AAASPS is a clinical trial comparing the effectiveness of ticlopidine hydrochloride (an anti-clotting agent) with aspirin in preventing recurrent stroke, heart attack and other vascular-related death.
Related chapters from BP7e: Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior; Chapter 19: Language and Hemispheric Asymmetry
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System; Chapter 15: Language and Our Divided Brain
Link ID: 3290 - Posted: 06.24.2010
St. Paul, MN – Using transplants of bone marrow cells improved the recovery from stroke in rat experiments, according to a study published in the August 27 issue of Neurology, the scientific journal of the American Academy of Neurology. The rats treated with an intravenous transplant of adult human stromal cells (mature cells from bone marrow) had significant improvements in their ability to function 14 days after the stroke, compared to rats that did not receive transplants after a stroke. "These are smart cells that selectively migrate to the site of injury and become little factories producing an array of helpful molecules to repair the tissue," said study author Michael Chopp, PhD, of Henry Ford Hospital in Detroit, Mich., and Oakland University in Rochester, Mich. "We believe this therapy shows promise in treating stroke, Parkinson's disease, spinal cord injury and traumatic brain injury."
Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 19: Language and Hemispheric Asymmetry
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 15: Language and Our Divided Brain
Link ID: 2545 - Posted: 06.24.2010