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dc.contributor.authorTremblay, Joshua
dc.contributor.otherQueen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.))en
dc.date.accessioned2019-04-25T15:30:46Z
dc.date.available2019-04-25T15:30:46Z
dc.identifier.urihttp://hdl.handle.net/1974/26126
dc.description.abstractThe endothelium is a single cell layer that plays a critical role in determining the health and function of blood vessels. Endothelial function is shaped by shear stress, the frictional force exerted by the speed of blood flow and the thickness (viscosity) of the blood. Exposure to shear stress that reverses direction back-and-forth impairs endothelial function in young men. Whether women are equally susceptible to this perturbation and the isolated impact of a low level of shear stress with and without reversal of shear had not been investigated. Hypoxia, the low levels of oxygen that are experienced at high-altitude, has been shown to influence flow reversal and impair endothelial function. However, no previous study had accounted for the changes in blood thickness, and hence shear stress that occur at high-altitude. This may be especially important in the context of excessive erythrocytosis, a high-altitude disease characterized by exceptionally thick blood and increased cardiovascular risk. This thesis examined 1) whether there are sex differences in the impact of exposure to low and reversing shear stress on endothelial function, 2) whether isolated low shear stress impairs endothelial function, 3) the impact of reversing shear stress on endothelial function in short-term exposure to low levels of oxygen and after trekking to 5050m in the Himalayas, and 4) the role of high levels of blood viscosity on endothelial function in high-altitude natives in Cerro de Pasco, Peru (4330m) with excessive erythrocytosis. We identified that 1) premenopausal women have some protection against reductions in endothelial function after being exposed to reversing shear stress, 2) isolated low shear stress impaired endothelial function, 3) short-term exposure to low levels of oxygen and sustained high-altitude exposure reduced endothelial function, while superimposing reversing shear stress had no effect, and 4) high levels of hemoglobin and blood viscosity contributed to lower endothelial function in Andean high-altitude natives with excessive erythrocytosis. Altogether, this dissertation advances our understanding of how the components of shear stress (the pattern, magnitude, and blood viscosity) impact endothelial function in humans under normoxic (normal levels of oxygen) and hypoxic (low levels of oxygen, such as high-altitude) conditions.en_US
dc.language.isoenen_US
dc.relation.ispartofseriesCanadian thesesen
dc.rightsCC0 1.0 Universal*
dc.rightsQueen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canadaen
dc.rightsProQuest PhD and Master's Theses International Dissemination Agreementen
dc.rightsIntellectual Property Guidelines at Queen's Universityen
dc.rightsCopying and Preserving Your Thesisen
dc.rightsThis publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.en
dc.rights.urihttp://creativecommons.org/publicdomain/zero/1.0/*
dc.subjectendothelial functionen_US
dc.subjecthigh altitudeen_US
dc.subjectphysiologyen_US
dc.subjectcardiovascularen_US
dc.subjectenvironmental physiologyen_US
dc.subjectvascular functionen_US
dc.subjectpolycythemiaen_US
dc.subjectchronic mountain sicknessen_US
dc.subjectoscillatory shear stressen_US
dc.subjectretrograde shear stressen_US
dc.titleShear Stress and Flow-Mediated Dilation in the Normoxic and Hypoxic Humanen_US
dc.typethesisen
dc.description.degreeDoctor of Philosophyen_US
dc.contributor.supervisorPyke, Kyra E
dc.contributor.departmentKinesiology and Health Studiesen_US


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Except where otherwise noted, this item's license is described as CC0 1.0 Universal