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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.
11

Inflammation in atherosclerosis

Jatta, Ken January 2006 (has links)
Consequences of atherosclerosis may result in a number of diseases of the cardiovascular system that represent serious health problems and major causes of morbidity and mortality worldwide. Although it is initially considered as disease of fibro-lipid and thrombus deposition in the arterial wall, it also involves an ongoing inflammatory response. Normally, the inflammatory response is considered as a protective defence mechanism of the body. However, if the inflammation gets out of proportion to the threat it is dealing with, it may then result in a sustained chronic disorder and thus may underlie the initial stage of atherogenesis. The work of this thesis focuses on the expression of cytokines/chemokines and the vascular transcriptional response to inflammation, i.e. LPS in atherosclerosis. This has mainly been studied in animal models of atherosclerosis; consequently, we set out to investigate these events using human material in vitro (human carotid lesions). Employing quantitative analysis, we were able to detect a significant induction of protein and mRNA of the cytokines IL-1β, IL-6, IL-10 and TNF-α and the chemokines IL-8 and MCP-1 by LPS in both atherosclerotic and non-atherosclerotic vessels. In contrast, LPS induction of TNF-α, IL-1β and IL-10 was solely observed in the lesions, but not in normal arteries. In addition, the impact of IL-1 gene polymorphism on the risk of myocardial infarction (MI) was estimated by DNA genotyping of 387 survivors of a first MI and 387 sex and age-matched control subjects. We found no statistically significant differences in either genotypic distribution or allelic frequencies of IL-1β (-511) or IL-1Ra (VNTR) polymorphisms between first-time survivors of myocardial infarction and their age-matched healthy controls. Incontrast, our results demonstrated a strong association between the IL-1Ra genotype and severity of angiographically determined coronary artery disease in post-MI patients. To further investigate the vascular response to inflammation, we used gene array analysis to evaluate the human vascular transcriptional response to LPS of non-atherosclerotic human renal arteries compared to carotid lesions. In LPS treated renal arteries, 54% of the transcripts gave a detectable signal, where 4% were upregulated and 3.8% down-regulated. In the LPS stimulated carotid lesions, 44% of transcripts were detected. In this latter group, 5.1% of transcripts were increased and 3.3% decreased. Interestingly, a newly identified virus-inducible antiviral protein, CMV inducible gene 5/viperin (Cig5), was among the most strongly induced gene in both normal and atherosclerotic biopsies. Single gene analysis revealed viperin in the endothelium of human atherosclerotic lesions. Further, viperin was induced in vascular cells by inflammatory stimuli and CMV infection. In conclusion we show that atherosclerotic vessels produce more proinflammatory cytokines/chemokines than normal vessels. Interestingly, our results indicate that LPS enhances the expression of cytokines/chemokines in a similar pattern both in lesions and normal arteries. However, the response is stronger in atherosclerotic lesions. Furthermore, our results suggest that genetic polymorphisms within the IL-1Ra loci may influence the severity of CAD. Finally, the CMV inducible gene 5/viperin have been identified as a putative culprit molecule in vascular inflammation and atherosclerosis.
12

Unresolved Issues in RNA Therapeutics in Vascular Diseases With a Focus on Aneurysm Disease

Schellinger, Isabel N., Dannert, Angelika R., Mattern, Karin, Raaz, Uwe, Tsao, Philip S. 04 April 2023 (has links)
New technologies have greatly shaped the scientific and medical landscape within the last years. The unprecedented expansion of data and information on RNA biology has led to the discovery of new RNA classes with unique functions and unexpected modifications. Today, the biggest challenge is to transfer the large number of findings in basic RNA biology into corresponding clinical RNA-based therapeutics. Lately, this research begins to yield positive outcomes. RNA drugs advance to the final phases of clinical trials or even receive FDA approval. Furthermore, the introduction of the RNA-guided gene-editing technology CRISPR and advances in the delivery ofmessenger RNAs have triggered a major progression in the field of RNA-therapeutics. Especially short interfering RNAs and antisense oligonucleotides are promising examples for novel categories of therapeutics. However, several issues need to be addressed including intracellular delivery, toxicity, and immune responses before utilizing RNAs in a clinical setting. In this review, we provide an overview on opportunities and challenges for clinical translation of RNA-based therapeutics, with an emphasis on advances in novel delivery technologies and abdominal aortic aneurysm disease where non-coding RNAs have been shown to play a crucial regulatory role.
13

Oxidants and antioxidants in cardiovascular disease

Ekblom, Kim January 2010 (has links)
Background Cardiovascular diseases, including myocardial infarction and stroke, are the main reason of death in Sweden and Western Europe. High iron stores are believed to produce oxygen radicals, which is the presumed putative mechanism behind lipid peroxidation, atherosclerosis and subsequent cardiovascular disease. Iron levels are associated with the hemochromatosis associated HFE single nucleotide polymorphisms C282Y and H63D. Bilirubin is an antioxidant present in relatively high levels in the human body. Several previous studies have found an association between high bilirubin levels and a lower risk for cardiovascular disease. Bilirubin levels are highly influenced by the common promoter polymorphism TA-insertion UGT1A1*28, the main reason for benign hyperbilirubinemia in Caucasians. There is a lack of prospective studies on both the association of iron and bilirubin levels, and the risk for myocardial infarction and ischemic stroke. Material and methods Iron, transferrin iron saturation, TIBC, ferritin and bilirubin were analyzed and HFE C282Y, HFE H63D and UGT1A1*28 were determined in myocardial infarction and stroke cases, and their double matched referents within the Northern Sweden Health and Disease Study Cohort. Results There were no associations between iron levels in the upper normal range and risk for myocardial infarction or stroke. No associations were seen for HFE-genotypes, except for a near fivefold increase in risk for myocardial infarction in HFE H63D homozygous women. Plasma bilirubin was lower in cases vs. referents both in the myocardial infarction and the stroke cohort. Despite a strong gene-dosage effect on bilirubin levels in both cases and referents, the UGT1A1*28 polymorphism did not influence the risk for myocardial infarction or stroke. Conclusion High iron stores are not associated with increased risk for neither myocardial infarction, nor stroke. There was no association between UGT1A1*28 and the risk for myocardial infarction or stroke. Consequently data suggests that other factors, which also may lower bilirubin, are responsible for the elevated risk observed in conjunction with lower bilirubin levels.
14

Retrospective analysis of the prescribing patterns of calcium channel blockers in a section of the private health care sector of South Africa / Ruan Smit

Smit, Ruan January 2010 (has links)
Background: Calcium channel blockers are mainly divided into antihypertensive and antianginal treatment agents. In 2000 it was estimated that 972 million adults worldwide were living with hypertension and it is expected to affect 1.56 billion patients by 2025. The incremental expenditure for the antihypertensive therapeutic group in the United States of America was estimated at $US 55 billion per annum in 2006. It was stated that around seven million people in the United States of America suffered from angina, with around 400 000 new reports every year. Objective: To determine the prescribing patterns of calcium channel blocker medicine items during 2005 to 2008 in a section of the private health care sector of South Africa. Methods: A retrospective quantitative drug utilisation review was done using a medicine claims database ranging over four years from 1 January 2005 to 31 December 2008. The total medicine claims database was divided into cardiovascular medicine items and then into calcium channel blockers. These were analysed according to age as well as gender. Further analysis included adherence of calcium channel blockers as well as an analysis of prescribers of these items during the study period. Results: The total number of patients on the medicine claims database consisted of 1 509 621 patients in 2005. This number decreased to 974 497 patients in 2008. The most medicine items were dispensed in 2006 (n = 21 113 422) with an average cost of R 92.82 (SD = 196.42) per medicine item. It was noted that 16.05% (n = 242 264) of patients used at least one cardiovascular item in 2005. The percentage of cardiovascular medicine item users increased by 4.36% during the study period to 20.41% (n = 198 847) in 2008. In 2008 the cardiovascular medicine items dispensed were responsible for 19.18% (R 342 565 308.41) of the total cost of all medicine items claimed. In 2005 the results revealed that 1.63% (n = 318 258) of all medicine items dispensed were calcium channel blocker medicine items. The percentage of calcium channel blockers increased to 2.24% (n = 367 437) of the total number of medicine items in 2008. The cost prevalence index was calculated for the calcium channel blockers and the value declined from 1.5 in 2005 to 1.22 in 2008, which indicated that the items dispensed were relatively expensive, but less than in 2005. An increase of 16.17% in the usage of generic medicine items were noted from 2005 to 2008. More female patients than male patients claimed medicine items during the study period. A higher percentage of male patients used a cardiovascular medicine item as well as calcium channel blockers during the study period compared to females and a larger percentage of their medicine expenditure was used on cardiovascular medicine items as well as calcium channel blockers compared to females. The usage of cardiovascular medicine items as well as calcium channel blocker medicine items increased with patient age. In 2008, 17.98% of patients older than 65 years of age used a calcium channel blocker compared to 0.97% of patients aged > 25 <= 35 years. Only 60.34% of calcium channel blockers items were used with acceptable refill adherence rates during the study. More than a third of the calcium channel blockers medicine items used had unacceptable low adherence rates from 2005 to 2008. In each of the study years the highest potential saving with generic substitution was seen with amlodipine containing items. It was also observed that some generic substitutions could be relatively more expensive than the innovator products and an increased cost instead of a saving through generic substitution may have occurred. Conclusion: This study highlighted the prescribing patterns and cost implications of calcium channel blockers in the private health care sector of South Africa. It is recommended that a more in–depth study of the adherence of calcium channel blockers be done. This study should also include the cost strategies of generic substitution of calcium channel blockers in South Africa. / Thesis (M.Pharm (Pharmacy Practice))--North-West University, Potchefstroom Campus, 2011.
15

Retrospective analysis of the prescribing patterns of calcium channel blockers in a section of the private health care sector of South Africa / Ruan Smit

Smit, Ruan January 2010 (has links)
Background: Calcium channel blockers are mainly divided into antihypertensive and antianginal treatment agents. In 2000 it was estimated that 972 million adults worldwide were living with hypertension and it is expected to affect 1.56 billion patients by 2025. The incremental expenditure for the antihypertensive therapeutic group in the United States of America was estimated at $US 55 billion per annum in 2006. It was stated that around seven million people in the United States of America suffered from angina, with around 400 000 new reports every year. Objective: To determine the prescribing patterns of calcium channel blocker medicine items during 2005 to 2008 in a section of the private health care sector of South Africa. Methods: A retrospective quantitative drug utilisation review was done using a medicine claims database ranging over four years from 1 January 2005 to 31 December 2008. The total medicine claims database was divided into cardiovascular medicine items and then into calcium channel blockers. These were analysed according to age as well as gender. Further analysis included adherence of calcium channel blockers as well as an analysis of prescribers of these items during the study period. Results: The total number of patients on the medicine claims database consisted of 1 509 621 patients in 2005. This number decreased to 974 497 patients in 2008. The most medicine items were dispensed in 2006 (n = 21 113 422) with an average cost of R 92.82 (SD = 196.42) per medicine item. It was noted that 16.05% (n = 242 264) of patients used at least one cardiovascular item in 2005. The percentage of cardiovascular medicine item users increased by 4.36% during the study period to 20.41% (n = 198 847) in 2008. In 2008 the cardiovascular medicine items dispensed were responsible for 19.18% (R 342 565 308.41) of the total cost of all medicine items claimed. In 2005 the results revealed that 1.63% (n = 318 258) of all medicine items dispensed were calcium channel blocker medicine items. The percentage of calcium channel blockers increased to 2.24% (n = 367 437) of the total number of medicine items in 2008. The cost prevalence index was calculated for the calcium channel blockers and the value declined from 1.5 in 2005 to 1.22 in 2008, which indicated that the items dispensed were relatively expensive, but less than in 2005. An increase of 16.17% in the usage of generic medicine items were noted from 2005 to 2008. More female patients than male patients claimed medicine items during the study period. A higher percentage of male patients used a cardiovascular medicine item as well as calcium channel blockers during the study period compared to females and a larger percentage of their medicine expenditure was used on cardiovascular medicine items as well as calcium channel blockers compared to females. The usage of cardiovascular medicine items as well as calcium channel blocker medicine items increased with patient age. In 2008, 17.98% of patients older than 65 years of age used a calcium channel blocker compared to 0.97% of patients aged > 25 <= 35 years. Only 60.34% of calcium channel blockers items were used with acceptable refill adherence rates during the study. More than a third of the calcium channel blockers medicine items used had unacceptable low adherence rates from 2005 to 2008. In each of the study years the highest potential saving with generic substitution was seen with amlodipine containing items. It was also observed that some generic substitutions could be relatively more expensive than the innovator products and an increased cost instead of a saving through generic substitution may have occurred. Conclusion: This study highlighted the prescribing patterns and cost implications of calcium channel blockers in the private health care sector of South Africa. It is recommended that a more in–depth study of the adherence of calcium channel blockers be done. This study should also include the cost strategies of generic substitution of calcium channel blockers in South Africa. / Thesis (M.Pharm (Pharmacy Practice))--North-West University, Potchefstroom Campus, 2011.
16

Cell states and transcriptional programs of the healthy human heart

Litviňuková, Monika 19 April 2023 (has links)
Das Herz ist das zentrale Kreislauforgan in unserem Körper und jede Abweichung seiner Funktion wirkt sich negativ auf die Homöostase des gesamten Körpers aus. Die Herzfunktion beruht auf der Synergie der Zellen, die das Organ bilden. Die detaillierte zelluläre Zusammensetzung sowie die Funktionalität der einzelnen Zellen müssen noch ermittelt werden, und diese Arbeit ist eine wichtige Ergänzung dieser Bemühungen. Dank der jüngsten Entwicklungen in den Einzelzelltechnologien sind wir nun in der Lage, Transkriptome einzelner Zellen aus komplexem Gewebe in beispiellosem Umfang zu charakterisieren. Im ersten Schritt eines solchen Experiments müssen die Zellen und Zellkerne aus dem Gewebe befreit und vereinzelt werden. Herzgewebe wirft in dieser Hinsicht einzigartige Herausforderungen auf, darunter die Knappheit des gesunden menschlichen Herzgewebes für die Forschung, das Vorhandensein von Kardiomyozyten, die aufgrund ihrer Größe nicht durch Microfluid-basierte Standardinstrumente passen und deren Multinukleation, sowie mögliche Voreingenommenheit verschiedener Methoden zur Gewebedissoziation. Hier präsentiere ich den umfassenden Zellatlas des gesunden erwachsenen menschlichen Herzens. Ich beginne mit der Methodenentwicklung zur Isolierung von einzelnen Zellen und Zellkernen aus Mausherzen. Um den Zellatlas des menschlichen Herzens zu erstellen, analysiere ich einen Datensatz von fast einer halben Million Einzelzellen und Zellkerne aus sechs Herzregionen von vierzehn gesunden Menschen. In diesem Atlas definieren wir 11 Hauptzelltypen und 62 Zellzustände des menschlichen Herzens. Ein tieferer Fokus wird auf das Herzgefäßsystem gelegt und die Zellen der arterio-venösen Achse sowie deren Wechselwirkungen und potenzielle Funktionalität werden definiert. Insgesamt präsentiert diese Dissertation einen komplex Datensatz aus menschlichem Herzgewebe und liefert neue Einblicke in die Biologie des gesunden Herzens mit Implikationen für kardiovaskuläre Erkrankungen. / The heart is the central circulatory organ in our bodies and any discrepancies of its function relative to healthy homeostasis negatively impact the whole body. Cardiac function relies on the synergy of all the cells that constitute the organ. The detailed cellular composition as well as the heterogeneity and functionality of the individual cells is yet to be established and this work is a major advance in this effort. Thanks to the recent developments in single cell genomics technologies, we are now able to profile transcriptomes from individual cells of complex tissues at unprecedented scale. In the first step of such an experiment, the single cells and nuclei need to be liberated from the tissue. Heart tissue presents a unique set of challenges in this regard, including the scarcity of healthy human cardiac tissue for research, large cardiomyocytes that do not fit into the standard droplet-based instruments, multinucleation of cardiomyocytes that might skew the proportions of the recovered nuclei as well as potential bias of tissue dissociation methods. Here I present a cell atlas of the free walls, apex and septum of the healthy adult human heart. I start with methods development for the isolation of single cells and single nuclei from mouse heart. Next, I move to the building of the atlas of the human cells and nuclei, where I describe the dataset of close to half a million single cells and nuclei sampled from 14 organ donors, defining 11 major cell types and 62 cell states of the heart. A deeper focus on the cardiac vasculature defined the cells of the arterio-venous axis as well as their interactions and potential functionality. Overall, this thesis presents a joined dataset of single cells and single nuclei from human cardiac tissues and provides new insights into cardiac biology in heath with implications for cardiovascular disease.
17

The role of fibroblast growth factor-23 in chronic kidney disease-mineral and bone disorder

Mirza, Majd A. I. January 2010 (has links)
Fibroblast growth factor-23 (FGF23) was initially identified as the causative factor of autosomal dominant hypophosphatemic rickets. Further studies confirmed that FGF23 is predominantly expressed in the osteocytes and osteoblasts of bone and that circulating FGF23 acts on the kidney to inhibit renal phosphate reabsorption and 1,25(OH)2D3 hydroxylation. With the progression of chronic kidney disease (CKD), the kidneys become insufficient to maintain a normal systemic mineral homeostasis, resulting in various abnormalities of bone and mineral metabolism, generally referred to as Chronic Kidney Disease – Mineral and Bone Disorders (CKD-MBD). FGF23 increases early in the course of CKD in order to maintain normal serum phosphate levels; long before a significant increase in serum phosphate can be detected. Recent studies suggest that increased FGF23 levels are associated with progression of CKD, mortality, and the development of refractory secondary hyperparathyroidism. Because FGF23 is the very earliest marker of CKD-MBD, it is of particular interest to evaluate the relation between FGF23 and CKD-MBD abnormalities, in the setting of early CKD and also in individuals with normal renal function. In the present work, we show that FGF23 is linked to several dynamic measurements of vascular function, including endothelial dysfunction, arterial stiffness, and atherosclerosis. FGF23 is also positively associated with left ventricular mass index and an increased risk of having left ventricular hypertrophy. All associations were independent of serum phosphate and were strengthened in subjects with diminished renal function. Furthermore, we found significant evidence for an association between higher FGF23 and increased fat mass and dyslipidemia, which could represent a novel pathway linking FGF23 to cardiovascular disease. Finally, we show that FGF23 is a significant predictor of future fracture risk. Although these associations could be reflecting the increased risk associated with hyperphosphatemia and calcitriol deficiency, current evidence points towards FGF23 being more than an innocent bystander. At the very least, FGF23 holds promise of being a bio-marker of cardiovascular status and phosphate-related toxicity both in CKD and in the general population, and might be a therapeutic target that could improve the fatal prognosis in CKD patients.

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