No description available.

Thesis (M.S.)--University of Iowa, 2008. / Thesis supervisor: Milan Sonka. Includes bibliographical references (leaf 32).

No description available.

No description available.

Thesis--University of Illinois. / Caption title. Reprinted, with modificatons, from Archives of pathology, v. 18, Oct.-Dec., 1934. Bibliography; p. 82-88.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1983. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Effective diagnosis of COA hinges on quantifications of the global hemodynamics (heart function metrics and workload), and the local hemodynamics (3-dimensional flow dynamics in COA). In this study, we developed an image-based framework that can quantify local and global hemodynamics for COA diagnosis. The proposed framework uses lattice Boltzmann method and lumped-parameter modeling that only needs routine non-invasive clinical patient data. The computational framework was validated against clinical cardiac catheterization data and Doppler echocardiographic measurements. One of the complicating factors of COA is its common association with mixed valvular diseases (MVD), which include varying combinations of aortic and mitral valve pathologies. Treatment strategies for these patients are quite unclear and differ from patient to patient. In order to evaluate risk factors and create guidelines for intervention aimed at minimizing the progression of cardiovascular disease, the impact of COA and MVD on aortic fluid dynamics in patients with COA and MVD was investigated in this thesis. Our results show that interaction of MVD with COA fluid dynamics may amplify adverse hemodynamic effects especially downstream of COA and may contribute to speed up the progression of the disease. The results suggest that some more aggressive surgical approaches may be required as regularly chosen current surgical techniques may not be optimal for patients with both COA and MVD. The appropriate surgical technique for COA repair often remains unclear for adult patients. Extra-anatomical bypass grafting has been recommended in some of the COA cases. To effectively evaluate risk status and create guidelines for intervention, precise quantification of aortic fluid dynamics and hemodynamics is required. We used a patient-specific numerical framework to investigate the impact of bypass grafts on aortic fluid dynamics in patients with COA. This study can partially explain the complications associated in patients with COA who underwent bypass grafting. / Dissertation / Doctor of Philosophy (PhD) / Coarctation of the aorta is a congenital narrowing of the proximal descending aorta which coexists with other cardiovascular diseases. Although accurate and early diagnosis of coarctation hinges on blood flow quantification, proper diagnostic methods for coarctation still lack because fluid-dynamics methods that can be used for accurate flow quantification are not well developed yet. We developed an image-based patient-specific computational framework that can quantify hemodynamics in patients with coarctation. Moreover, we investigated the impact of coarctation coexisting with other diseases and its interventions on hemodynamics to answer clinical questions.

Introduction: There is progressive stiffening and dilatation of the aorta and large elastic arteries with aging as a result of the repetitive cyclic stress they are exposed to throughout life. Aortic stiffening has a number of detrimental effects including an increase in aortic pulse wave velocity and early wave reflection, isolated systolic hypertension, ventricular-vascular mismatch, impaired coronary blood flow reserve, and is the fundamental cause of heart failure in the elderly. The aim of this thesis is to provide proof of concept for the aortic wrap procedure; a surgical treatment of stiffening and dilatation of the ascending aorta with aging. The surgical procedure involves wrapping an elastic material around the ascending aorta of elderly patients, to reduce the stiffness and diameter of the ascending aorta towards that seen in youth. Methods: Proof of concept is investigated in the following studies. 1. The effect of the elastic wrap on the in-vivo stiffness of the normal aorta. 2. The effect of the elastic wrap on the in-vivo stiffness of the dilated and stiffened aorta. 3. The effect of the elastic wrap on the in-vitro stiffness of the aged human ascending aorta and on aortic pressure. 4. The effect of wrapping the aged human ascending aorta on pulse pressure (mathematical model). 5. The effect of chronic implantation on the structure of the normal aorta. 6. The mechanical properties of the ovine thoracic aorta and the elastic wrap material. Results: 1. Elastic wrap application increased the in-vivo stiffness of the normal aorta. 2. Elastic wrap application decreased the stiffness of the stiffened and dilated aorta. 3. Elastic wrap application decreased the in-vitro stiffness of the elderly human ascending aorta and pulse pressure. 4. A reduction in ascending aortic stiffness was sufficient to reduce ascending aortic pulse pressure. Conclusion: Application of the elastic wrap to the aged human ascending aorta is expected to reduce aortic stiffness, as well as systolic and pulse pressure, and to increase diastolic pressure with a reduction in cardiac load. The aortic wrap procedure may be an effective surgical procedure for the treatment of heart failure and isolated systolic hypertension.

Orientador: Cristina Antoniali Silva / Banca: Angelina Zanesco / Banca: Carlos Renato Tirapelli / Resumo: Estudos têm mostrado que em ratas prenhas normotensas ou hipertensas (SHR) há uma diminuição significativa da pressão arterial nos períodos finais da prenhez diretamente associada à redução da atividade simpática perivascular de leitos mesentéricos de ratas normotensas ou hipertensas (SHR). Essas alterações têm sido atribuídas a uma importante participação dos fatores relaxantes derivados do endotélio com destaque ao óxido nítrico (NO). Estudos recentes do nosso laboratório sugerem que o aumento da síntese de NO pela enzima óxido nítrico sintase endotelial (eNOS) ao final da prenhez ocorre por uma via menos dependente de cálcio, associada a fosforilação da eNOS em resíduos de Serina 1177, através da via PI3K/Akt/eNOS. Por outro lado, ratas hipertensas não prenhas apresentam uma disfunção endotelial e vascular ocasionada pelo aumento na produção de espécies reativas de oxigênio (ERO), sendo o complexo enzimático NAD(P)H oxidase, uma importante fonte de ERO. A produção de ERO modula a biodisponibilidade de NO. Assim, uma diminuição das ERO durante a prenhez poderia contribuir para a redução da PA e modulação da reatividade vascular, dependente do endotélio, aos agonistas vasoconstritores. Nossa hipótese é que em SHR prenhas, a redução da produção de ERO na aorta contribuiria para o aumento da biodisponibilidade do NO e para a hiporreatividade de aortas à fenilefrina (PE). Para isso, o estresse oxidativo sistêmico e da aorta (TBARS) foram avaliados em ratas Wistar e SHR, prenhas (P) e não prenhas (NP). Analisamos o efeito hipotensor da Apocinina (30 mg/kg) e do Tempol (30 mg/kg). Anéis intactos de aorta torácica de P e NP foram estimulados com PE antes e após incubação (30 min) com Apocinina (100 μmol/L) ou Tempol (0,1 nmol/L)... / Abstract: Studies have shown that in normotensive or hypertensive pregnant rats (SHR) there is a significant decrease in blood pressure in late pregnancy directly associated with the reduction in sympathetic perivascular activity of mesenteric beds of normotensive or hypertensive rats (SHR). These changes have been attributed to an important role of endothelium-derived relaxing factors especially to nitric oxide (NO). Recent studies in our laboratory suggest that increased synthesis of NO by endothelial nitric oxide synthase (eNOS) in late pregnancy is of a less calcium-dependent pathway associated with phosphorylation of eNOS on serine 1177 through via PI3K/Akt/ eNOS. On the other hand, do not exhibit a pregnant hypertensive rats and the vascular endothelial dysfunction caused by increased production of reactive oxygen species (ROS), the NAD(P)H oxidase enzyme complex, a major source of ROS. The ROS modulate the bioavailability of NO. Thus, a reduction of ROS during pregnancy could contribute to the reduction in blood pressure and modulation of vascular reactivity endothelium-dependent, to vasoconstrictor agonists. Our hypothesis is that in pregnant spontaneous hypertensive rats (SHR), the reduction of ROS production in the aorta contribute to increase the bioavailability of NO and hyporeactivity to aortae phenylephrine (PE). For this reason, systemic oxidative stress and aorta (TBARS) were valued in Wistar and SHR rats, pregnant (P) and non-pregnant (NP). We analyzed the hypotensive effect of Apocynin (30 mg/kg) and Tempol (30 mg/kg). Intact rings of thoracic aorta of P and NP were stimulated with PE before and after incubation (30 min) with apocynin (100 mmol/L) or Tempol (0,1 nmol/L)... / Mestre

Charles University Faculty of Pharmacy in Hradec Kralove Department of Farmacology & Toxikology Student: Martina Fišrová Supervisor: PharmDr. Marie Vopršalová, CSc. Title of diploma thesis: The effects of some flavonoids on isolated rat aortic rings Flavonoids are secondary plant metabolites that are profusely represented in nature. They are known for their wide range of effects and many of them have beneficial effects on the human body. Above all, they have anti-bacterial and anti-inflammatory properties and effects on cardiovascular system - they cause vasodilation. The aim of this diploma thesis was to investigate vasorelaxation effects of selected flavonoids from the group of flavonolignans - 2,3-dehydrosilybin A (DHS-A), 2,3-dehydrosilybin B (DHS-B) and metabolites, which are components of the silymarin complex found in the plant Silybum marianum (Asteraceae). The vasorelaxation potential of tested substances was verified in ex vivo conditions on isolated rat aortic rings. The effect of increasing doses of individual substances in precontracted aortic rings with intact endothelium was measured. From the measured values, the DRC curves were constructed and EC50 values were determined. The analysis of the results shows, that DHS-A (EC50 = 30,1 mol/l) had the most signifiant activity. Its...