The tenn Acute Coronary Syndrome (ACS) encompasses a spectrum of patients who present with chest discomfort or other symptoms caused by myocardial ischemia or infarction. Since critical or acute care nurses care for such patients, they should have a thorough knowledge of ACS pathophysiology and current treatments for ACS The purpose of this research study is to explore and describe the knowledge level that the critical care nurses in a state hospital in East Texas feel they have regarding ACS. This study was quantitative, descriptive and contextual in design, in which a sample survey was performed, using a questionnaire based on a literature study. The response of most ofthe critical care nurses tested was that they felt they had insufficient knowledge. An in-service training session has been proposed to help improve the nurses' knowledge and expertise on ACS. / Health Studies / M.A. (Nursing Science)

Submitted in fulfillment of the Degree of Masters in Technology: Clinical Technology, Durban University of Technology, 2011. / Background: Idiopathic dilated cardiomyopathy (IDC) is a primary myocardial disease of unknown cause characterized by left ventricular or biventricular dilatation and impaired myocardial contractility. Idiopathic dilated cardiomyopathy (IDC) is the second commonest cause of heart failure in Africa. Some patients with idiopathic dilated cardiomyopathy present with significant pulmonary hypertension (PHT) which maybe out of keeping with the usual degree of PHT seen in patients with this disorder. Methods and Material: This is a prospective and longitudinal follow-up study of 66 patients with IDC who were evaluated after satisfying the inclusion and exclusion criteria of this study. The clinical evaluation of each patient included a complete medical history, physical examination, 12 lead electrocardiogram, 2D-echocardiography, continuous wave (CW), pulsed wave (PW), and tissue Doppler imaging (TDI). Results: The mean age of all patients was 48.5 ± 12.8, with 39/66 (59.1%) patients being male. The prevalence of pulmonary arterial hypertension (PAH) was documented in 47 patients (71.2%, 95% CI: 59 - 83%). Mean left ventricular ejection fraction (LVEF) was 25.3 ± 8.8%, and mean left atrial volume index (LA volume) was 44.5±19.8 ml/m2. Mitral regurgitation (MR) occurred in 56/66 (84.8%) of patients with moderate or severe MR detected in 60.6% of all cases of IDC. The presence of a tricuspid regurgitant jet was found in 56/66 (84.9%), with (95% CI: 75 -93%). Right ventricular dilatation was found in 65/66 (98.5%), with (95% CI: 95 - 101%). ii Age, LA volume, LVEF and MR were included into a multivariate logistic regression model to predict PAH. Only MR presence was independently associated with PAH adjusted (OR 6.02, 95% CI: 1.15- 31.47) (p= 0.03). Conclusion: The study has shown that there is a significant prevalence of pulmonary arterial hypertension (PAH), right heart involvement and tricuspid regurgitant jet in IDC patients. The present study also showed that in patients with dilated cardiomyopathy, the degree of mitral regurgitation was a good predictor of PAH.

Thesis (MSc)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: Introduction: It is well documented that insulin offers cardioprotection under ischaemic stress. In the past it was believed that the protective effects of insulin, such as the (a) recruitment of glucose transporters to enhance glucose entry into the cell, (b) stimulation of glycolysis, (c) enhancement of glycogen synthesis, (d) improved protein synthesis, and (e) positive inotropic and chronotropic properties, were metabolic of origin, but lately the emphasis has shifted towards the diverse signal transduction pathways elicited by insulin. Although these beneficial effects of insulin on ischaemia/reperfusion induced injury have been studied for many years, the exact protective mechanism is still not resolved. Aim: To investigate the influence of insulin on the signaling pathways as a possible protective mechanism against ischaemia/reperfusion and therefore to investigate the possible roles and cross signaling of cyclic adenosine monophosphate (cAMP), protein kinase B (PKB) and p38 mitogen activated protein kinase (p38 MAPK) in the cardioprotection offered by insulin to the reperfused, ischaemic myocardium. Materials and methods: Isolated rat hearts were perfused retrogradely in accordance with the Langendorff technique (95%02, 5% C02). After 30 min of stabilization, hearts were subjected to 30 min global low flow ischaemia (0,2 ml/min), followed by 30 min of reperfusion. Hearts perfused with standard Krebs Henseleit solution containing 5 mM glucose were compared to hearts perfused with a perfusion solution containing 5 mM glucose and 0,3 IlIU/ml insulin. Wortmannin was added during either ischaemia or reperfusion. Left ventricular developed pressure (LVDP), rate pressure product (RPP), tissue cAMP and PKB and p38 MAPK activation were measured. Results: Insulin treated hearts showed improved functional recovery (P<0.05) during reperfusion after ischaemia vs. non-insulin treated hearts (85.5±4.6% vs. 44.8±4.9%). However, the addition of wortmannin (a Pl3-kinase inhibitor) to the perfusion solution during either ischaemia or reperfusion abolished the improved recovery. At the end of ischaemia, cAMP levels of the insulin treated hearts were elevated significantly, while the cAMP content in the non-insulin treated hearts returned to control levels. Addition of wortmannin during ischaemia abolished this rise in cAMP. Wortmannin added during reperfusion only did not alter the levels of cAMP at the end of reperfusion. Activation of p38 MAPK was transient during ischaemia for both insulin and non-insulin treated hearts. Addition of wortmannin during ischaemia did not alter p38 MAPK levels at the end of ischaemia. P38 MAPK was activated significantly (P<0.001) in the non-insulin treated hearts vs. insulin treated hearts during reperfusion. Wortmannin, added at the onset of reperfusion, could partially abolish the effects of insulin to suppress p38 MAPK activation after 30 min of reperfusion. Activation of PKB in insulin treated hearts was significantly higher than non-insulin treated hearts during stabilization and early ischaemia. This activity was depressed by 30 min of ischaemia in both presence and absence of insulin. Wortmannin, when added before induction of ischaemia did not further lower this. The presence of insulin resulted in occurrence of strong PKB activation during reperfusion, peaking at 15 minutes and diminishing at 30 minutes. Wortmannin, added at the onset of reperfusion, abolished PKB activity measured at the end of reperfusion. Conclusion: Insulin exerted a positive inotropic effect and delayed the onset to ischaemic contracture. Inhibition of Pl3-kinase by wortmannin abolished the protective effects of insulin, arguing for an insulin stimulated PKB involvement in cardiac protection. Insulin also increased cAMP production and attenuated activation of p38 MAPK, both associated with improved recovery. This evidence suggested possible cross signaling between different signaling pathways. / AFRIKAANSE OPSOMMING: Agtergrond: Insulin beskerm harte wat aan isgemiese stres blootgestel word. Alhoewel hierdie voordelige effekte van insulien reeds vir verskeie jare bestudeer is, is die presiese meganisme waarmee insulien die hart beskerm steeds nie duidelik nie. Navorsers het die beskermende effekte van insulien aan metaboliese gevolge soos: (a) verhoogde glukose transport d.m.v. inspanning van meer glukose transporters (b), stimulering van glikolise, (c) vebeterde glikogeensintese, (d) verhoogde proteiensintese, en (e) die positiewe inotropiese en chronotropiese eienskappe van insulien toegeskryf. Onlangs het die fokus verskuif na ander diverse seintransduksiepaaie. Doel: Die doel van hierdie studie was dus om die moontlike betrokkenheid van hierdie sientransduksiepaaie asook die interaksie tussen sikliese adenomonofosfaat (cAMP), proteïn kinase B (PKB) en p38 MAPK in die beskerming wat insulien aan die isgemiese, gereperfuseerde miokardium bied, te bestudeer. Materiale en Metodes: Geïsoleerde rotharte is geperfuseer in ooreenstemming met die Langendorff metode. Na 30 min van stabilisasie is harte blootgestel aan 30 min. globale lae vloei isgemie (0,2 ml/min), en daarna is harte vir 30 min. geherperfuseer. Harte wat geperfuseer is met 'n perfusaat wat 5mM glukose bevat is vergelyk met harte wat geperfuseer is met 'n perfusaat wat 5mM glukose en 0,3 ~IU/ml insulien bevat. Sommige harte is geperfuseer met 'n perfusie oplossing waar wortmannin bygevoeg is tydens óf isgemie óf tydens herperfusie. Linker ventrikulêre ontwikkelde druk (LVDP), tempo-druk produk (RPP), weefsel cAMP-vlakke asook PKB en p38 MAPK aktiwiteit is gemeet. Resultate: Insulien-behandelde harte het funksioneel beduidend beter herstel tydens herperfusie na isgemie as harte wat nie met insulien behandel is nie (85.5±4.6% vs. 44.8±4.9%). Byvoeging van wortmannin by die perfusie oplossing tydens óf isgemie óf reperfusie, het die toename in herstel wat gesien is in die insulien-behandelde harte, opgehef. Die cAMP vlakke in die insulienbehandelde harte het aan die einde van isgemie beduidend gestyg (P<0.001), terwyl vlakke in harte wat nie met insulien behandel is nie, na kontrole vlakke teruggekeer het. Die teenwoordigheid van wortmannin in die perfusie oplossing tydens isgemie, het die styging in cAMP voorkom , terwyl die byvoeging van wortmannin tydens herperfusie. nie die cAMP vlakke beïnvloed het nie. Die aktivering van p38 MAPK tydens isgemie was van verbygaande aard in beide die insulien-behandelde harte en harte wat nie met insulien behandel is nie. Die byvoeging van wortmannin tydens isgemie het nie die p38 MAPK aktivering beïnvloed nie. P38 MAPK is beduidend geaktiveer tydens herperfusie in harte wat nie met insulien behandel is nie vergeleke met die insulien-behandelde harte. Die byvoeging van wortmannin tydens reperfusie kon die effek van insulien om p38 MAPK aktivering te onderdruk, gedeeltelik ophef. PKB aktivering tydens die stabilisasie fase en vroeë isgemie was beduidend hoër in die insulien-behandelde harte vs. die harte wat nie met isulien behandel is nie. Die aktiwiteit is onderdruk deur 30 min isgemie ongeag die teenwoordigheid van insulien. Die byvoeging van wortmannin tydens isgemie het PKB aktivering nie verder verlaag nie. Die teenwoordigheid van insulien het 'n sterk aktivering van PKB tydens herperfusie veroorsaak met 'n piek na 15 min en 'n verlaging na 30 min. Wortmannin bygevoeg aan die begin van herperfusie, het PKB aktiwiteit opgehef aan die einde van reperfusie. Opsomming: Insulien het 'n positiewe inotropiese invloed gehad, en het die begin van isgemiese kontraksie vertraag. Die inhibisie van Pl3-kinase deur wortmannin het die beskermende effekte van insulin opgehef, wat 'n insulin gestimuleerde PKB betrokkenheid aandui. Insulien het ook verhoogte cAMP produksie en verlaagde p38 MAPK aktivering tot gevolg gehad, en beide is geassosieer met verbeterde herstel. Hierdie resultate dui dus op moontlike interaksie tussen die verskillende seintransduksiepaaie.

The aim of this work was to study the expression of proteins involved in reactions in which harmful free radicals are degraded in an organism. was observed difference between the expression of selected myocardial proteins in non-influenced animals, animals who were treated with low dosage of morphine (0.1 mg/kg/day or 1 mg/kg/day), and animals administered high dosage of morphine (10 mg/kg/day). Low dosages were administered for 28 days and high dosage for 10 days. In addition, the effect of abstinence lasting one week was assessed after cessation of morphine administration (1 mg/kg/day). Morphine at low dosage (0.1 mg/kg/day) increased levels of glutathion peroxidase-1/2, which may be considered as one of the possible consequences of the ongoing oxidative stress. There were no significant differences in glutathion peroxidase-6 expression. Next aim of this work was to study the expression of antioxidant enzymes. These experiments were carried out on myocardial preparations from the animals treated with a constant dosage of morphine (10 mg/kg/day) for 10 days. Samples from these animals were used for measuring the total antioxidant capacity of the left and right ventricles. These samples were also used for determination of concentration of the oxidative stress marker 8-isoprostane. We also aimed to...

Heart disease is a major cause of death in western countries. In order to diagnose and monitor heart disease, 3D echocardiography is an important tool, as it provides a fast, relatively low-cost, portable and harmless way of imaging the moving heart. Segmentation of cardiac walls is an indispensable method of obtaining quantitative measures of heart function. However segmentation of ultrasound images has its challenges: image quality is often relatively low and current segmentation methods are often not fast. It is desirable to make the segmentation technique as fast as possible, making quantitative heart function measures available at the time of recording. In this thesis, we test two state-of-the-art fast segmentation techniques to address this issue; furthermore, we develop a novel technique for finding the best segmentation propagation strategy between points of time in a cardiac image sequence. The first fast method is Graph Cuts (GC), an energy minimisation technique that represents the image as a graph. We test this method on static 3D echocardiography to segment the myocardium, varying the importance of the regulariser function. We look at edge measures, position constraints and tissue characterisation and find that GC is relatively fast and accurate. The second fast method is Random Forests (RFos), a discriminative classifier using binary decision trees, used in machine learning. To our knowledge, we are the first to test this method for myocardial segmentation on 2D and 3D static echocardiography. We investigate the number of trees, image features used, some internal parameters, and compare with intensity thresholding. We conclude that RFos are very fast and more accurate than GC segmentation. The static RFo method is subsequently applied to all time frames. We describe a novel optical flow based propagation technique that improves the static results by propagating the results from well-performing time frames to less-performing frames. We describe a learning algorithm that learns for each frame which propagation strategy is best. Furthermore, we look at the influence of the number of images and of the training set available per tree, and we compare against other methods that use motion information. Finally, we perform the same propagation learning method on the static GC results, concluding that the propagation method improves the static results in this case as well. We compare the dynamic GC results with the dynamic RFo results and find that RFos are more accurate and faster than GC.

O objetivo desta tese é avaliar a expressão do miRNA-423-5p, em diferentes sítios, em modelo experimental de remodelamento cardíaco após insulto isquêmico em ratos. Os animais foram randomizados em grupos SHAM (cirurgia sem oclusão da artéria coronária descendente anterior esquerda) ou IAM (cirurgia com ligadura da artéria coronária descendente anterior esquerda) e acompanhados por 1, 7, 28 e 90 dias. Após o tempo de seguimento, os animais foram submetidos ao ecocardiograma e eutanasiados. Foi retirado sangue do plexo retroorbital, sangue venoso e arterial e coletado tecido do músculo gastrocnêmio e do ventrículo esquerdo separando as áreas remota (REM), infartada (INF) e peri-infartada (PERI). A partir da homogeneização dos tecidos, foi realizada a extração de miRNA e sua expressão quantificada pelo método de PCR em tempo real. Também foi mensurado os níveis plasmáticos do peptídeo natriurético cerebral (BNP). Os dados foram analisados pela teste de ANOVA de uma e duas vias e correlações através do programa estatístico SPSS 21.0. Quanto a caracterização do modelo utilizado, podemos verificar que a fração de ejeção do ventrículo esquerdo dos ratos IAM foram menores que os do grupo SHAM e os percentuais de área acinética foram iguais em todos os grupos IAM, como esperado. Também observamos que o miRNA-423-5p é expresso no coração, nos diferentes segmentos analisados, apresentando variação significativa nos tempos avaliados, correlacionado-se positivamente com o tamanho do infarto e negativamente com a fração de ejeção do ventrículo esquerdo. Diante deste cenário, nossos achados solidificam o conceito de que a expressão do miRNA-423-p se altera ao longo do tempo após insulto isquêmico e pode ter papel relevante no remodelamento cardíaco de origem isquêmica. / The objective of this project was to evaluate the expression of miRNA-423-5p in an experimental model of cardiac remodeling after ischemic injury in rats. Animals were randomized to SHAM group (surgery without occlusion of the left anterior descending coronary artery) or acute myocardial infaction (AMI) group (surgery with ligation of the left anterior descending coronary artery) and followed for 1, 7, 28 and 90 days. After the follow-up period, the animals were submitted to echocardiography and euthanized. Blood from the retroorbital plexus, venous and arterial blood was collected; and gastrocnemius and left ventricle tissue was collected, separating the remote (REM), infarcted (INF) and peri-infarcted (PERI) areas. From the homogenization of tissues, miRNA was extracted and its expression quantified by real-time PCR. Plasma levels of brain natriuretic peptide (BNP) were also measured by ELISA. Data were analyzed by one-way and two-way ANOVA and coefficient correlations were calculated using the statistical package SPSS 21.0. Regarding the experimental model, we could verify that the left ventricular ejection fraction of the AMI rats were reduced compared to the SHAM group and the percentages of akinetic area were the same in all AMI groups, as expected. We also observed that miRNA-423-5p is expressed in the heart in the different segments analyzed, showing significant variation in the different periodos that were evaluated, is positively correlated with infarct size and negatively with left ventricular ejection fraction. In this scenario, our findings solidify the concept that miRNA-423-p expression changes over time after an ischemic insult and may play a relevant role in the cardiac remodeling of ischemic origin.

by Lam Wai Yip. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 184-195). / Contents --- p.I - IV / Abstract --- p.V / Abbreviations --- p.VI / List of Tables and Figures --- p.VII - XV / Chapter Chapter One: --- Introduction / Part I / Chapter 1.1 --- Human genome project --- p.1 / Chapter 1.2 --- Progress of human genome project --- p.2 / Chapter 1.3 --- Human heart cDNA sequencing --- p.3 / Chapter 1.4 --- Significance of the human heart cDNA library project --- p.5 / Chapter 1.5 --- Homology search tools for cDNA sequences alignment --- p.5 / Part II / Chapter 1.6 --- Investigation of a human heart cDNA clone A076 --- p.7 / Chapter 1.7 --- General introduction of Heat Shock Proteins (HSPs) --- p.7 / Chapter 1.7.1 --- Definition of HSP --- p.8 / Chapter 1.7.2 --- Discovery of HSP --- p.10 / Chapter 1.7.3 --- Transcriptional regulation of heat shock genes --- p.11 / Chapter 1.7.4 --- Nomenclature of HSPs --- p.13 / Chapter 1.7.5 --- HSP110 --- p.13 / Chapter 1.7.6 --- HSP90 --- p.14 / Chapter 1.7.7 --- HSP70 --- p.15 / Chapter 1.7.8 --- HSP60 --- p.17 / Chapter 1.7.9 --- Ubiquitin - HSP8 --- p.19 / Chapter 1.7.10 --- HSP27 --- p.20 / Chapter 1.8 --- The theme of this thesis --- p.28 / Chapter Chapter Two: --- Method and Materials / Chapter 2.1 --- The human heart cDNA library --- p.29 / Chapter 2.2 --- Plating out the cDNA library --- p.29 / Chapter 2.3 --- DNA amplification --- p.31 / Chapter 2.4 --- DNA sequencing reaction - Cycle sequencing reaction --- p.32 / Chapter 2.5 --- Operation of the A.L.F. DNA sequencer --- p.33 / Chapter 2.5.1 --- Preparation of the gel cassette --- p.33 / Chapter 2.5.2 --- Preparation of the acrylamide gel --- p.34 / Chapter 2.5.3 --- Fitting the gel cassette into the electrophoresis unit --- p.35 / Chapter 2.5.4 --- Settings of electrophoresis --- p.36 / Chapter 2.6 --- Comparison of DNA sequences to databases --- p.37 / Chapter 2.7 --- Programming for sending cDNA sequences to NCBI --- p.38 / Chapter 2.8 --- Storage of sequence data --- p.39 / Chapter 2.9 --- Synthesis and purification of primers --- p.40 / Chapter 2.10 --- Connection of cDNA clones using Polymerase Chain Reaction (PCR) --- p.41 / Chapter 2.11 --- Purification of DNA fragment from agarose gels by GENECLEAN´ёØ --- p.42 / Chapter 2.12 --- "Preparation of competent Escherichia coli for transformation (Hanahan, 1986)" --- p.43 / Chapter 2.13 --- Transformation of Plasmid into Competent Escherichia coli --- p.44 / Chapter 2.14 --- "Small scale preparation of plasmid DNA (Sambrook et al.,1989" --- p.45 / Chapter 2.15 --- Large scale plasmid preparation by QIAGEN´ёØ --- p.46 / Chapter 2.16 --- DNA sequencing reaction - Unicycle sequencing reaction --- p.48 / Chapter 2.17 --- Synthesis of Radiolabeled DNA probe --- p.49 / Chapter 2.18 --- "Isolation of genomic DNA from human blood cells (Thomas A. Ciulla, 1988)" --- p.51 / Chapter 2.19 --- Southern blotting --- p.52 / Chapter 2.20 --- Prehybridization and hybridization procedure for Southern blot analysis --- p.54 / Chapter 2.21 --- "AGPC-RNA extraction method (Chomczynski and Sacchi 1987, modifed)" --- p.56 / Chapter 2.22 --- Electrophoresis of RNA through gels containing formaldehyde --- p.58 / Chapter 2.23 --- First-Strand cDNA synthesis --- p.59 / Chapter 2.24 --- Use of T7 RNA polymerase to direct expression of the cloned hsp27b gene (A076&B490) --- p.60 / Chapter 2.25 --- "Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (Laemmli, 1970)" --- p.61 / Chapter 2.26 --- Staining of the Gel by the Commassie Blue Method --- p.63 / Chapter Chapter Three: --- Results / Part I / Chapter 3.1 --- Sample results of Sequencing a few clones --- p.64 / Chapter 3.2 --- A Catalogue of 497 cDNA clones obtained from human heart cDNA sequencing --- p.71 / Chapter 3.3 --- Submission of novel sequences to genbank --- p.81 / Chapter 3.4 --- A Catalogues of genes that are expressed in the adult human heart --- p.83 / Chapter 3.5 --- The use of the programmes to assist the sending and receiving of sequence data E-mail message --- p.90 / Chapter 3.5.1 --- The use of the SENDMAIL.EXE programme --- p.91 / Chapter 3.5.2 --- "The use of the EDITBLN.EXE, ALLFILE.EXE and DATABASE.EXE" --- p.95 / Part II / Chapter 3.6 --- DNA sequence profiles of cDNA clones A076 and B490 --- p.105 / Chapter 3.7 --- Ligation of cDNA clones using Polymerase Chain Reaction (PCR) --- p.112 / Chapter 3.8 --- Cloning of the PCR product A076&B490 into the pAED4 expression vector --- p.117 / Chapter 3.9 --- Unicycle sequencing of the subcloned insert A076&B490 --- p.121 / Chapter 3.10 --- Southern hybridization of hsp27b (A076&B490) --- p.125 / Chapter 3.11 --- Results of RT-PCR and PCR --- p.127 / Chapter 3.12 --- Expression pAED4-A076&B490 in E.coli --- p.133 / Chapter Chapter Four: --- Discussion / Part I / Chapter 4.1 --- EST characterization --- p.138 / Chapter 4.2 --- Further investigation --- p.140 / Chapter 4.3 --- Disadvantage of randomly picked cDNA sequencing --- p.141 / Chapter 4.4 --- Problem of GenBank database searching --- p.141 / Part II / Chapter 4.5 --- The DNA sequence of A076 and B490 --- p.143 / Chapter 4.6 --- Ligation of HSP27B by using PCR --- p.144 / Chapter 4.7 --- Analysis of the DNA and protein sequence ofhsp27b (A076&B490) --- p.145 / Chapter 4.8 --- Southern hybridization of human hsp27b --- p.153 / Chapter 4.9 --- "RT-PCR and PCR of first strand cDNA with primers A076-ATG, A076-mid and oligo dT" --- p.153 / Chapter 4.10 --- Expression of human hsp27b --- p.154 / Chapter 4.11 --- The possible roles of human hsp27b --- p.156 / Chapter 4.12 --- Further analysis --- p.160 / Appendix I --- p.161-182 / Appendix II --- p.183 / References --- p.184-195

A long held hypothesis in mitochondrial biology holds that increases in mitochondrial Ca2+ levels stimulate the activity of matrix dehydrogenases that catalyze production of NADH and eventually donate electrons to electron transport in order to increase ATP formation. At the same time, mitochondrial Ca2+ overload is a deleterious event leading to opening of the mitochondrial permeability transition pore, increasing reactive oxygen species and initiating pathways that contribute to cell death. These fundamental hypotheses are best studied in the heart because of the critical energy supply-demand relationship in myocardium, but were untestable in vivo until the discovery of the mitochondrial Ca2+ uniporter (MCU). The molecular identity of the MCU pore forming subunit was recently discovered, which allowed me to study a transgenic mouse with myocardial delimited expression of a dominant negative MCU. My lab developed mice with myocardial-delimited transgenic expression of a dominant negative MCU to test these fundamental hypotheses and to determine how MCU controls physiological and pathological stress responses in vivo, ex vivo, and in situ. My studies provide new, unanticipated information that contributes to our understanding the relationship between mitochondrial Ca2+, oxygen utilization, cardiac pacemaking and pathologic stress responses in heart. Here, I show that mice with myocardial-targeted MCU inhibition have hearts with surprisingly high oxygen consumption rates due to elevated cytoplasmic Ca2+ in response to physiological stress. Loss of MCU effectively preserved inner mitochondrial membrane potential and prevented an oxidative burst thought to drive myocardial injury and death, but nevertheless failed to protect myocardium from ischemia-reperfusion injury. Increases in oxygen consumption, elevation in cytoplasmic Ca2+ and transcriptional reprogramming mitigate the protective actions of MCU inhibition in vivo. Mice with myocardial selective MCU inhibition have a reduced response to isoproterenol-induced heart rate increase but have normal baseline heart rates. My studies provide novel insight into how MCU contributes to myocardial Ca2+ homeostasis, metabolism, and transcription leading to surprising actions on physiological and pathophysiological responses in heart.

<p>The pumping performance of the heart is affected by the mechanical properties of the muscle fibre part of the cardiac wall, the myocardium. The myocardium has a complex structure, where muscle fibres have different orientations at different locations, and during the cardiac cycle, the myocardium undergoes large elastic deformations. Hence, myocardial strain pattern is complex. In this thesis work, a computation method for myocardial strain and a detailed map of myocardial transmural strain during the cardiac cycle are found by the use of surgically implanted metallic markers and beads. The strain is characterized in a local cardiac coordinate system. Thereafter, non-invasive phase contrast magnetic resonance imaging (PC-MRI) is used to compare strain at different myocardial regions. The difference in resolution between marker data and PC-MRI data is elucidated and some of the problems associated with the low resolution of PC-MRI are given.</p>

The pumping performance of the heart is affected by the mechanical properties of the muscle fibre part of the cardiac wall, the myocardium. The myocardium has a complex structure, where muscle fibres have different orientations at different locations, and during the cardiac cycle, the myocardium undergoes large elastic deformations. Hence, myocardial strain pattern is complex. In this thesis work, a computation method for myocardial strain and a detailed map of myocardial transmural strain during the cardiac cycle are found by the use of surgically implanted metallic markers and beads. The strain is characterized in a local cardiac coordinate system. Thereafter, non-invasive phase contrast magnetic resonance imaging (PC-MRI) is used to compare strain at different myocardial regions. The difference in resolution between marker data and PC-MRI data is elucidated and some of the problems associated with the low resolution of PC-MRI are given.