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 What’s Inside Stroke: brain attack Early treatment Side effects Bench to bedside Sidebar: What is a stroke? Research Views Responding to the reader Cellular construction Staying alive Research outside the lab The road to commercialization 2005-2006 Lionel McLeod Scholarship winner AHFMR announces $48 million for health research Reader Resources |
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Stroke: brain attack In the depths of the Health Sciences Building at Calgary’s Foothills Medical Centre, researchers from various disciplines investigate the structural and functional changes that occur in disease.The Experimental Imaging Centre (EIC) provides access to Canada’s largest Tesla magnet for magnetic resonance (MR) and optical imaging, in order to investigate ways to improve the diagnosis, monitoring, and treatment of medical disorders. Heritage Clinical Investigator and neurologist Dr. Philip A. Barber conducts stroke research in the EIC, as well as stroke diagnosis and care in the Seaman Family MR Research Centre and the Hotchkiss Brain Institute. Stroke is a sudden loss of brain function caused by the interruption of blood flow to the brain, through either ischemia (blood-vessel blockage) or hemorrhage (blood-vessel rupture). In Canada, stroke is the single most common cause of neurological disability and death; 5,000 strokes occur every year in Alberta alone. If you live to the age of 80, you have a 1-in-4 chance of suffering a disabling stroke. Early treatment Early treatment can be very beneficial; unfortunately patients often do not recognize the warning signs of stroke—such as loss of speech, loss of motor skills, and loss of vision—and are slow to seek diagnosis and treatment. A clot-busting drug called tissue plasminogen activator (tPA) can improve the outcome of acute ischemic stroke; but few stroke patients are eligible, since the treatment must be administered quickly. “In Calgary, we’re treating about 10% of all strokes with tissue plasminogen activator, but we’d like it to be 20%,” says Dr. Barber. “In the United States they treat about 1% of all strokes with tPA. Calgary is doing better than most places in the world, but we could do better.” Side effects Some patients experience significant side effects with tPA. Researchers believe that these adverse effects are strongly related to the initial breakdown of the blood-brain barrier—the membrane that controls the passage of substances from the blood into the central nervous system. Current imaging techniques for the brain in stroke cannot predict which patients are susceptible to the side effects. Dr. Barber—in collaboration with chemists, physicists, biologists, molecular biologists, and clinicians—studies the blood-brain barrier. The breakdown of this barrier is one of the first things to happen in stroke, he explains. “If we could understand this process better, we could target various treatments; and also, with the imaging, we could actually define whether our therapeutic intervention had any effect,” says Dr. Barber. Bench to bedside “Whilst we’re working in research and trying to answer academic questions, the questions are essentially relevant to stroke patients,” he points out. “What we intend to do is to translate information from bench to bedside. This environment is quite novel. There are people like myself working alongside basic scientists from all fields, and down the corridor I can be seeing a patient in five minutes. We have the capacity to take information from the Experimental Imaging [Centre] over to the Seaman Family MR Centre for clinical application. “We’re at the beginning of our research,” he continues. “There’s much work to do, but it’s exciting to have an idea, design a study, collect the data, and do the analysis. Sometimes your question will provide an answer which may be novel and which may potentially provide a new unders tanding of stroke, and ultimately a novel therapy.” Dr. Philip Barber is a Heritage Clinical Investigator and an assistant professor in the Department of Clinical Neurosciences, as well as a Clinical Stroke Fellow in the Calgary Stroke Program at the University of Calgary. He receives research support from the Heart and Stroke Foundation of Canada and the Canadian Institutes of Health Research (CIHR). Dr. Barber is also a member of the Hotchkiss Brain Institute. The University of Calgary Faculty of Medicine, in a unique collaboration with the NRC (National Research Council Canada) Institute for Biodiagnostics and AHFMR, provided funding for the Experimental Imaging Centre (EIC) and its ultra-high-field 9.4-Tesla MRI system. Selected publications Barber PA, Foniok T, Kirk D, Buchan AM, Laurent S, Boutry S, Muller RN, Hoyte L, Tomanek B, Tuor UI. MR molecular imaging of early endothelial activation in focal ischemia. Annals of Neurology 2004 Jun 28;56(1):116-120. Barber PA, Demchuk AM, Zhang J, Buchan AM. Validity and reliability of a quantitative computed tomography score in predicting outcome of hyperacute sroke before thrombolytic therapy. Lancet 2000 May 13;355(9216):1670-1674. Sidebar: What is a stroke? A stroke is a sudden loss of brain function caused by the interruption of blood flow to the brain (an ischemic stroke) or the rupture of blood vessels in the brain (a hemorrhagic stroke). Both types of stroke cause brain cells (neurons) in the affected area to die. The effects of a stroke depend upon where the brain was injured, as well as how much damage occurred. A stroke may affect - ability to move and coordinate movement; - ability to feel touch, temperature, pain, and movement; - ability to see or to interpret what you see; - ability to think, remember, understand, plan, reason, or problem-solve; - ability to communicate (speaking and understanding speech, as well as reading, writing, and the ability to do mathematics); - personality; - emotions; - behaviour. What is a “mini-stroke”? A “mini-stroke” is a transient ischemic attack (TIA) caused by a temporary interruption of blood flow to the brain. TIA symptoms are similar to those of an ischemic stroke, except that they go away in a few minutes or hours (no more than 24 hours). A TIA is an important warning sign that you may be at risk for an ischemic stroke in the future. What are the warning signs of stroke? Learn to recognize the warning signs of a stroke: Weakness – sudden weakness, numbness, or tingling in the face, arm, or leg Trouble speaking – sudden temporary loss of speech, or trouble understanding speech Vision problems – sudden loss of vision (particularly in one eye), or double vision. Courtesy: Heart and Stroke Foundation of Canada |