Browsing by Subject "Myocardial Infarction"
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Item Alcohol and Heart Attacks: What’s the story?(2009-05-04) Clarke, Michael EMultiple large studies have found that drinking roughly one or more drinks per night reduces the risk of myocardial infarction. That being said, alcohol use is associated with notable adverse effects, including but not limited to, psychosocial disability, addiction, excess dietary calories, motor vehicle accidents, loss of productive work hours, and increased tendency towards violence and risky sexual practices. Although safe and moderate alcohol consumption may minimize these risks, a physician recommendation to drink alcohol for a “healthy heart” is likely not warranted at this time.Item Engineered Cardiac Tissues for Delivery of Cells to the Injured Myocardium(2015-07) Wendel, JacquelineWith the high incidence of heart failure in the developing world and the inherent risks and limited availability of donor hearts, cell-based solutions have become an attractive solution. However, current methods to deliver cells to the heart have resulted in limited long term cell retention and consequently minimal therapeutic efficacy. In this work, we aim to use engineered tissues as a means to deliver cells to the injured myocardium post- infarction with increased cell retention. The results detailed in this dissertation indicate that engineered tissues can be constructed from both primary rodent cardiomyocytes and human pluripotent stem cell derived cardiomyocytes, and that these tissues not only engraft post-infarction with high cell retention , but in some instances also result in improved cardiac function and limitation of left ventricular remodeling postinfarction.Item My Chest Hurts, Am I Having a Heart Attack?(2010-09-15) McKinney, ZekeThe only symptom ruling out an immediate heart attack in a non-urgent setting is the presence of chest-wall tenderness. No signs or symptoms of a patient’s chest pain history can definitively identify a diagnosis of an immediate heart attack in the non-urgent care setting, but they should be evaluated carefully.Item Myocardial Energetic Alterations In Post Myocardial Infarction Left Ventricular Remodeling, Hibernating Myocardium And Pacing Induced Congestive Heart Failure And Amelioration With Stem Cell Transplantation(2011-08) Jameel, MohammadPost infarction left ventricular (LV) remodeling is associated with decreased Phosphocreatine/Adenosine triphosphate (PCr/ATP) ratio and these abnormalities are worsened during increased cardiac workload. However, chronic hibernating myocardium is able to preserve a normal energetic state as reflected by a normal PCr/ATP ratio up to 6 months despite a reduction in perfusion reserve and regional function. Furthermore, the decrease in PCr/ATP ratio with increased workload in hibernating myocardium is similar to normal myocardium. This is probably related to an intrinsic down-regulation in the mitochondrial function which minimizes oxidative stress and leads to a balanced supply and demand at baseline and increased work load. Congestive heart failure (CHF) is associated with intrinsic alterations in mitochondrial oxidative phosphorylation and significant decrease in PCr/ATP ratio which are independent of ischemia. ATP sensitive potassium (KATP) channel blockade in the failing heart is associated with a significant decrease in the PCr/ATP ratio and ATP production rate via Creatine Kinase which is associated with a decrease in myocardial blood flow and tissue hypoxia. Thus, in failing hearts the balance between myocardial ATP demands (or oxygen demands) and delivery are critically dependent on functioning KATP channels. Bone marrow derived multiprogenitor cell (MPC) transplantation in a porcine model of post infarct LV remodeling resulted in long term improvement in ventricular function and myocardial bioenergetics despite minimal engraftment of stem cells. Vascular density in the border zone was increased after cell transplantation. In vitro, the stem cells significantly inhibited Tumor Necrosis Factor alpha induced mitochondrial membrane potential change and cytochrome C release from myocytes. Cell transplantation also resulted in long term differential expression of genes which included a downregulation of mitochondrial oxidative enzymes and upregulation of Myocyte Enhancer Factor 2a (MEF2a) and ZFP91. Thus, the beneficial effects of stem cell transplantation are most likely related to the "trophic effects" of cells on the host myocardium, which include promotion of angiogenesis, maintenance of mitochondrial integrity, and inhibition of apoptosis of ischemia threatened and overstretched myocytes in the border zone myocardium along with differential expression of genes relating to metabolism and apoptosis.