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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Roles of c-Jun in angiogenesis and cancer: insights using gene targeting approaches

Zhang, Guishui, Medical Sciences, Faculty of Medicine, UNSW January 2006 (has links)
Cardiovascular disease and cancer are the two most common causes of death worldwide. Angiogenesis plays a critical role tumourigenesis and atherogenesis. As a member of the basic region-leucine zipper protein family, c-Jun, has been linked with cell proliferation, migration and cell survival. However, the relationship between c-Jun and angiogenesis has not been firmly established. In this thesis, strategies targeting c-Jun mRNA such as DNAzyme and siRNA have been designed and evaluated for their ability to inhibit the c-Jun mRNA and c-Jun protein expression in vitro and in vivo. These agents block c-Jun expression and inhibit DNA binding activity of c-Jun. Luciferase assay showed that c-Jun siRNA suppressed c-Jun/AP-1-dependent reporter activity. The processes of cell proliferation, migration, invasion and tube formation were all down-regulated after treatment with c-Jun targeting agents. In vivo, c-Jun DNAzymes and siRNA inhibit angiogenesis in multiple models of angiogenesis in multiple models of angiogenesis, including tumour angiogenesis and growth, matrix angiogenesis, corneal angiogenesis and retinal neovascularization. This is mediated, at least in part, by c-Jun siRNA or DNAzyme inhibition of MMP-2 expression. These findings demonstrate the critical role played by c-Jun in the involvement of neovascularization and suggest that DNAzymes or siRNAs are efficient gene-silencing agents. The ability to identify and control key genes in angiogenesis provides opportunities for developing therapeutic molecular tools to treat cancer or other angiogenesis related diseases.
62

Roles of c-Jun in angiogenesis and cancer: insights using gene targeting approaches

Zhang, Guishui, Medical Sciences, Faculty of Medicine, UNSW January 2006 (has links)
Cardiovascular disease and cancer are the two most common causes of death worldwide. Angiogenesis plays a critical role tumourigenesis and atherogenesis. As a member of the basic region-leucine zipper protein family, c-Jun, has been linked with cell proliferation, migration and cell survival. However, the relationship between c-Jun and angiogenesis has not been firmly established. In this thesis, strategies targeting c-Jun mRNA such as DNAzyme and siRNA have been designed and evaluated for their ability to inhibit the c-Jun mRNA and c-Jun protein expression in vitro and in vivo. These agents block c-Jun expression and inhibit DNA binding activity of c-Jun. Luciferase assay showed that c-Jun siRNA suppressed c-Jun/AP-1-dependent reporter activity. The processes of cell proliferation, migration, invasion and tube formation were all down-regulated after treatment with c-Jun targeting agents. In vivo, c-Jun DNAzymes and siRNA inhibit angiogenesis in multiple models of angiogenesis in multiple models of angiogenesis, including tumour angiogenesis and growth, matrix angiogenesis, corneal angiogenesis and retinal neovascularization. This is mediated, at least in part, by c-Jun siRNA or DNAzyme inhibition of MMP-2 expression. These findings demonstrate the critical role played by c-Jun in the involvement of neovascularization and suggest that DNAzymes or siRNAs are efficient gene-silencing agents. The ability to identify and control key genes in angiogenesis provides opportunities for developing therapeutic molecular tools to treat cancer or other angiogenesis related diseases.
63

Roles of c-Jun in angiogenesis and cancer: insights using gene targeting approaches

Zhang, Guishui, Medical Sciences, Faculty of Medicine, UNSW January 2006 (has links)
Cardiovascular disease and cancer are the two most common causes of death worldwide. Angiogenesis plays a critical role tumourigenesis and atherogenesis. As a member of the basic region-leucine zipper protein family, c-Jun, has been linked with cell proliferation, migration and cell survival. However, the relationship between c-Jun and angiogenesis has not been firmly established. In this thesis, strategies targeting c-Jun mRNA such as DNAzyme and siRNA have been designed and evaluated for their ability to inhibit the c-Jun mRNA and c-Jun protein expression in vitro and in vivo. These agents block c-Jun expression and inhibit DNA binding activity of c-Jun. Luciferase assay showed that c-Jun siRNA suppressed c-Jun/AP-1-dependent reporter activity. The processes of cell proliferation, migration, invasion and tube formation were all down-regulated after treatment with c-Jun targeting agents. In vivo, c-Jun DNAzymes and siRNA inhibit angiogenesis in multiple models of angiogenesis in multiple models of angiogenesis, including tumour angiogenesis and growth, matrix angiogenesis, corneal angiogenesis and retinal neovascularization. This is mediated, at least in part, by c-Jun siRNA or DNAzyme inhibition of MMP-2 expression. These findings demonstrate the critical role played by c-Jun in the involvement of neovascularization and suggest that DNAzymes or siRNAs are efficient gene-silencing agents. The ability to identify and control key genes in angiogenesis provides opportunities for developing therapeutic molecular tools to treat cancer or other angiogenesis related diseases.
64

A study of assessing knowledge and health beliefs about cardiovascular disease among selected undergraduate university students using Health Belief Model.

Gautam, Yuba Raj 01 December 2012 (has links)
Background: In the United States, Cardiovascular Disease (CVD) is the leading cause of death for both men and women. According to National Vital Statistics Report (2009), heart disease was the number one killer in the United States and it can be prevented. The primary purpose of this study was to determine knowledge and health beliefs about CVD among selected undergraduate university students and find out the potential risk of developing CVD in this population. The secondary purpose was to assess the relationship between knowledge, health beliefs, and personal risks; the tertiary purpose was to determine the factors that predict the relationship between demographic variables and cardiovascular risk factors among these students. Methods: A cross-sectional, descriptive, and correlational survey design was used in this quantitative study. An existing knowledge and health belief instrument was adapted with the permission from the authors. In the 2012 Spring semester, over 600 undergraduates from Foundation of Human Health, First Aid and CPR, Medical Terminology, Math, History, and Geography classes at a mid-western university were surveyed to access knowledge and health beliefs about CVD. The Health Belief Model provided the theoretical framework for this study. Results: Demographic data provided descriptive overview of the participants in this study. Majority of the participants were whites, lived off campus, and were domestic students. Results from data analysis revealed that overall knowledge about cardiovascular disease was low among these university students. Individual health beliefs such as perceived susceptibility, severity, and barriers regarding CVD were low; however perceived benefits of preventing CVD were found high. Most of the undergraduate university students were at potential risk of developing cardiovascular disease. Smoking and stress causing CVD were lesser known among undergraduate university students. Time to cook healthy meals and unaffordability of buying healthy foods were significant barriers in protecting cardiovascular health among university students. There was a positive statistically significant correlation between CVD knowledge, knowledge subtypes, and health belief subscales. Correlations between knowledge and health beliefs were weaker while comparing to correlation between CVD knowledge and knowledge subtypes. Race/ethnicity, age, family history, international/national, live on/off campus, and number of health classes were the better predictors of cardiovascular knowledge, while perceived barrier was the strongest predictor of health belief about CVD among undergraduate university students.
65

The prevalence and determinants of subclinical atherosclerosis in an early inflammatory polyarthritis inception cohort

Mirjafari, Hoda January 2011 (has links)
Introduction: Patients with inflammatory polyarthritis (IP) have an excess risk of cardiovascular (CVD) mortality due to accelerated atherosclerosis. Markers identifying individuals with subclinical atherosclerosis as measured by carotid intima-medial thickness (cIMT) and plaque may allow for attenuation of CVD risk. The objective of this study was to identify associated risk markers for atheromatous plaque and cIMT in an incident cohort of patients with early IP and to assess the risk markers associated with progression of cIMT and plaque after 2 years of follow-up.Methods: From 2004 to 2008 consecutive patients with early IP (≥2 joints swollen for ≥4 weeks) aged 18-65 years, who were within 24 months of symptom onset (±6 months) were recruited as part of a primary-care-based inception cohort. Apparently healthy controls were recruited on a frequency matched 'buddy' pair system. Patients underwent joint and blood pressure examination. Patients and controls underwent BMI measurement and their medication was recorded. Patients' blood was taken for measurement of rheumatoid factor, anti-citrullinated protein antibody, C reactive protein, glucose, lipids (LDL, HDL, triglycerides, paroxonase 1, apolipoprotein A1 and B) and markers of vascular damage (E-selectin, VCAM) and adipocytokines (leptin and adiponectin). Patients and controls underwent B mode Doppler ultrasound examination of the carotid arteries to assess for cIMT and the presence of plaque. In univariate analyses we identified factors that were associated with cIMT and plaque presence after age and gender adjustment. An additive stepwise multivariable logistic regression model was created to investigate the independence of any associations.Results: The 329 IP subjects had a median (IQR) age of 51 (42-58) years and 96 (29%) were male. IP subjects were more likely to be smokers, have a family history of CVD, have diabetes, higher BP and be overweight than their apparently healthy counterparts. IP subjects with plaque at baseline often did not have prior CVD. Subjects with IP had a 2.87 fold higher plaque frequency at the baseline but a similar median cIMT relative to the controls. Traditional CVD risk markers such as age, systolic BP and LDL were associated with cIMT and plaque at baseline. Adiponectin levels were negatively associated with cIMT and positively associated with plaque. IP subjects had a significant increase in their cIMT in the first 2 years of follow-up. The rate of progression of cIMT was 1.5-2.2 fold greater in IP than reported in the general population. Novel risk factors added to the model above and beyond traditional risk factors in predicting atherosclerosis. Steroid exposure at 2 years was associated with atherosclerosis progression.Conclusion: Markers known to be associated with atherosclerosis in the general population are associated with cIMT and plaque presence in early IP prior to established inflammatory disease and therapy. While cIMT in subjects and controls was the same at baseline there was an accelerated rate of progression of cIMT in IP subjects relative to that reported in the general population.
66

NON-INVASIVE QUANTIFICATION OF CARDIOVASCULAR FLOW METRICS IN VERTEBRATES

Sreyashi Chakraborty (10797369) 14 May 2021 (has links)
<p>Cancer and cardiac diseases are the major causes of morbidity and mortality in the western world. Cardiovascular hemodynamics is increasingly being used to understand the pathophysiological progression of these diseases. Advancements in imaging modalities and development of multiscale numerical models have opened avenues for innovative quantification of flow metrics that may potentially aid in clinical diagnosis. The motivation behind this dissertation is to investigate three different physiological flow phenomena and develop new flow specific parameters as explained in the following paragraphs.</p> <p>Drug transport efficacy in treating breast tumors has a strong correlation with tissue architecture, nanoparticle transport parameters and hemodynamic metrics that varies from one patient to another. The exact time interval between nanoparticle introduction and drug release must be accurately determined to achieve therapeutic efficacy. The first chapter of the current work implements a numerical model based on mixture theory equations to investigate effect of varying inter-capillary separation on solute transport in dual-channel tissues for various solute sizes (0.5-15 nm) and molecular weights (0.1-70 kDa). The predictive capability of the numerical model is validated by measurements of dextran transport in an invitro tumor platform containing multiple blood vessels. The main contribution of this work is in reporting a unique non-dimensional time at which solute concentration peaks in any location in the tissue in absence of pharmacokinetics.</p> <p> The second chapter focuses on the development of a physics-based metric from color-m-mode (CMM) echocardiography scans to correctly diagnose different stages of left ventricle diastolic dysfunction (LVDD). Current practice of diagnosing LVDD involves calculating a combination of parameters like intraventricular pressure difference (IVPD) and propagation velocity (Vp) from the CMM scans. The conventional Vp measurement is based on heuristics. This definition does not utilize the entire information from the spatio-temporal velocity distribution of the ventricle filling cycle. The present work challenges the underlying assumption of the early ventricle filling wave moving with a constant velocity. The proposed method in this chapter uses wavelets to analyze the early diastolic ventricle filling wave and introduces a wavelet based peak propagation velocity (Peak-Vw). Peak-Vw is free of the inherent assumptions of the subjective selection of an iso-contour in the scan and measuring a slope from it. The novelty of the Peak-Vw measurement can provide new insights for understanding the complicated pathophysiology of the left ventricle (LV) diastolic function.</p> <p>The final focus of this dissertation is to investigate the evolving hemodynamics of the cardiovascular system of Japanese medaka while it is growing from embryonic state to larval stages. Cross-correlation of red blood cell patterns from 2D micro-particle image velocimetry (µPIV) images provide measurements of velocity fields in the fish heart and vessels. Accurate velocity gradient measurements are required to further derive flow quantities like wall shear stress (WSS), pressure drop across valves and cardiac strain. </p> <p>WSS experienced by endocardial cells and vascular endothelial cells are linked to changes in cardiac specific gene expressions. Previous studies with other vertebrate models investigating mechano-genetic correlations were focused on mutating genes or introducing some perturbation in the blood circulation. In the third chapter of this dissertation, a baseline longitudinal study tracking the change in cardiovascular WSS and gene expressions with natural progression of fish age is presented for the first time. Peak WSS changes with fish age calculated at the valves located at the ventricle inflow (AVC) and outflow (OFT), at the caudal artery (CA) showed an inflection trend that coincides with developmental landmarks of cardiac morphogenesis. Retrograde flow in the medaka heart valve locations have been documented for the first time. Contrary to intuition, the caudal and dorsal vessels in the fish tail displayed a reduction in cross-sectional area with age progression. Identification of these unique trends in the mechano-genetic tapestry of vertebrates prepares the ground for future studies that can test the mechano-transduction mechanisms.</p> <p>The fourth chapter delves deeper into the flow induced pressure drop (<a>ΔP</a>) across the AVC and OFT of the ventricle and the peak strain experienced by the ventricle wall remodeling through fish age progression. Valve regions record the dynamic variations of ΔP that may induce WSS fluctuations with age progression. A variation of cardiac strain with age is the key driver of varying chamber morphology. This is the first study in teleost species literature that analyzes the endocardial work (EW) calculated from a ΔP-strain loop. The increase in EW observed across fish age progression can be directly related to the heart’s metabolic demand. EW can be used in future studies of human hearts to distinguish between healthy and diseased ventricles.</p> <p>Overall, this dissertation provides an in-depth study of three separate biophysical processes of the vertebrate cardiovascular system and designs new metrics that have translational clinical potential.</p>
67

The effect of periodontal pathogens and their products on cardiovascular disease

Chiang, Lauren January 2013 (has links)
Periodontal disease is a condition in which the gums and bones surrounding the teeth are inflamed. It is a common cause of oral discomfort and tooth loss, but in recent years has been linked to a variety of systemic problems. Among them is cardiovascular disease, which is the top cause of death in the developed world. There is evidence that periodontal pathogens invade the bloodstream from the gingival pockets and contribute to the progression of disease through a variety of different mechanisms. First, they initiate the systemic inflammatory process by invading and activating vascular endothelial cells to upregulate adhesion molecules and chemokines, which then in turn activate macrophages to take up low density lipoprotein and deposit it on the luminal wall. Atherosclerotic plaque is pro-thrombotic, which increases the chances of forming blood clots and ischemic attacks. Periodontal pathogens also can induce the proliferation of antibodies that can cross-react with self-antigens, resulting in an autoimmune disease. The presence of these pathogens also causes oxidative stress through the production of reactive oxygen species, which is highly damaging. Since these pathogens have many ways of contributing to cardiovascular diseases, it has been hypothesized that treating the periodontal problems will help prevent the progression of cardiovascular disease. Several studies show that addressing periodontitis has resulted in decreased levels of inflammatory markers like C-reactive protein, interleukin-6, and fibrinogen, lower incidences of stroke, decreased blood pressure and lipid levels, and a lower left ventricular mass.
68

Determining the association between density muscarinic acetylcholine receptor M3 in myocardium and tunica media of coronary vasculature and self-reported disease states

Tse, Shiaomeng 09 June 2023 (has links)
INTRODUCTION: Myocardial infarction causes parasympathetic dysfunction in cardiovascular tissue, where central parasympathetic drive decreases but local acetylcholine levels are unchanged. The muscarinic acetylcholine receptor M3 (AChM3R) is shown to have mediating effects in cardiac tissue and vasculature, such as regulation of heart rate and vasodilation of coronary arteries. The objective of this study is to determine the association between AChM3R levels in the heart wall and in the coronary vasculature with self-reported disease states from cadaver donor records. METHODS: Biopsies of the left anterior descending (LAD) artery and the underlying anterior interventricular septum (AIVS) were taken from 14 cadavers. A 5 mm biopsy of the LAD and its underlying AIVS were harvested 2.54-3.81cm from the bifurcation point of the left coronary artery, depending on the tissue integrity of the cadaver specimen. The tissues were immunostained for AChM3R (CHRM3 NB100-58975 at 1:2000) and visualized using a DAB chromogen. Slides were digitally scanned into a virtual image at 20x using the Motic Easyscan (Motic, Inc.). Images were segmented for tunica media and myocardium using Adobe Photoshop CS (Adobe, Inc.). We developed code in Python to calculate the strong positive and positive staining of the tissues. The number of pixels stained was normalized to the tissue area. The donors from which tissue was biopsied were classified into cardiovascular, cerebrovascular, Alzheimer’s disease dementia (AD), or both cerebrovascular and AD disease categories based on self-reported donor declarations. We used SPSS (v27, IBM, Inc.) to run a Pearson correlation to determine the association of staining positivity in the anatomical regions and a MANOVA to determine significant differences in the amount of pixel positivity in the tunica media and myocardium as a function of disease classification. RESULTS: Strong positive and positive staining of the myocardium were not correlated with strong positive in the tunica media. There was a significant positive relationship between strong myocardium staining and positive tunica media staining (r =.727, n=14, p=.003) as well as positive myocardium and positive tunica media staining (r=.674, n=14, p=.008). There was no significant difference between the amount of AChM3R staining and disease classification. CONCLUSIONS: The lack of correlation between strong positive in the myocardium and positive and strong positive in the tunica media suggests that the AChM3R state in the heart wall is independent of changes in the AChM3R of coronary vascular smooth muscle. However, significant correlation between strong positive in the myocardium and positive in the tunica media indicates that changes in AChM3R in the myocardium could be dependent on the presence of a baseline amount of AChM3R in the coronary vascular smooth muscle. Categorization of donor disease states may be too broad to provide statistical significance. Many donors reported co-morbid diseases, which could have affected the influence of cardiovascular disease and dementia on AChM3R modulation. These findings highlight that interventions targeting parasympathetic dysfunction of coronary vasculature may leave the underlying heart wall unaffected. Future studies should consider cardiovascular disease diagnoses to assess AChM3R distribution in the heart wall and coronary vasculature.
69

Should we Standardise how Heart Rate is Measured?

Mohee, K., Khan, M.M., Akeroyd, L., Scally, Andy J., Morley, C. January 2014 (has links)
No / Introduction There is increasing evidence that lowering HR in cardiovascular disease may be beneficial. Recent trials have documented heart rate (HR) using supine ECG and the NICE guideline for heart failure[1,2] suggests lowering HR below 75 bpm but without specifying how HR should be measured. There is no published data on how HR measured by supine ECG compares to “real world” measurement in the clinic or surgery and any discrepancy might lead to overzealous introduction of HR lowering treatment. Method HR was measured in 136 consecutive patients attending a new cardiology OP clinic. Three methods of measuring HR were compared in the following sequence: Supine HR measured by ECG “real world” measurement by the nurse using Dynamat (auto) Manually over 30 sec during examination (Dr). Patients with dysrhythmia were excluded. Findings HR measured using these 3 methods has been presented separately and has shown a significant difference with ECG HR slower on average by >6bpm vs. either auto or Dr Measurement. The table shows the number and % of patients where HR was either ≥ 70bpm (Shift evidence) or ≥ 75 bpm (Nice guidelines) measured by one or two methods but not all three. Conclusion Real world HR measurement is consistently higher than supine ECG HR and may therefore lead to over inclusive treatment according to guideline recommendations. The method used to measure HR should be defined both in clinical trials and in published guidelines. Supine ECG is suggested as the preferred method for documenting HR prior to initiating rate lowering therapy.
70

L'efficacité limitée des antagonistes non-peptidiques de l'angiotensine II dans un modèle animal de resténose et développement d'un nouveau modèle animal de resténose

Pham, Dung January 1996 (has links)
Les maladies cardio-vasculaires sont responsables de la vaste majorité des décès dans les pays industrialisés. La plupart de ces maladies sont dues à l'athérosclérose, processus manifesté par le développement de lésions (plaques d'athéromes) dans les parois vasculaires. La présence de ces plaques conduit à la réduction de la lumière du vaisseau et, par conséquent, à des complications graves, tel que l'infarctus du myocarde. Les patients ont pour issue la méthode d'angioplastie qui consiste à écraser la plaque athéromateuse à l'aide d'un ballonnet pour accroître la lumière du vaisseau obstrué. Toutefois, cette intervention entraîne une abrasion de l'endothélium et un étirement important des cellules musculaires lisses (CML) situées dans la profondeur de la paroi. Chez environ un tiers à la moitié des patients, la multiplication des CMLs conduit à une nouvelle réduction de la lumière artérielle. C'est la resténose. Les travaux de recherche ont permis le déploiement de plusieurs thérapies pharmacologiques et mécaniques mais les résultats tant anticipés suite aux études animales ne sont pas reproductibles chez l'humain pour la vaste majorité des tactiques. Notre équipe s'est intéressée au Système Rénine-Angiotensine (SRA) car son implication dans la resténose est non-négligeable. De plus, le succès des inhibiteurs de l'enzyme de conversion de l'angiotensine (iECA) chez l'animal a confirmé son rôle. Cependant, les essais cliniques ne sont guère convaincants et c'est ce qui a incité plusieurs à s'intéresser aux récepteurs de !'angiotensine II (Ang Il). Nos études antérieures avec le modèle de la carotide de rat ont révélé que les antagonistes non-peptidiques de l' Ang II sélectifs pour AT[indice inférieur 1] diminuaient partiellement la prolifération néointimale. Parallèlement, nous avions traité nos animaux avec un antagoniste peptidique non-sélectif pour réaliser que ce dernier en inhibait la presque totalité. Notre hypothèse de travail est que les antagonistes nonpeptidiques et les iECAs ont une efficacité limitée sur la réduction myointimale. Nous avons effectué une courbe dose-réponse avec un antagoniste non-peptidique sélectif pour AT[indice inférieur 1] et une seconde courbe avec un antagoniste non-peptidique mais sélectif pour les deux sous-types de récepteurs (AT[indice inférieur 1] et AT[indice inférieur 2]. De plus, nous avons traité nos animaux avec un iECA seul et combiné avec un antagoniste non-peptidique. Le bilan confirme l'efficacité limitée des antagonistes non-peptidiques de I' Ang II et établit que la coapplication de drogues ne suffit pas pour réduire la prolifération néointimale avec la même efficacité qu'observée avec l'antagoniste peptidique. Dans un deuxième temps, nous avons cherché à développer un nouveau modèle animal de la resténose afin de palier aux critiques dont font l'objet les modèles actuels et aussi permettre la validation de nos données antérieures. Nous suggérons que le furet pourrait devenir une bonne alternative aux modèles existants.

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