Diss. (sammanfattning) Uppsala : Univ., 2001. / Härtill 5 uppsatser.

Thesis (doctoral)--Lund University, 1992. / Added t.p. with thesis statement inserted.

Thesis (doctoral)--Lund University, 1992. / Added t.p. with thesis statement inserted.

Balloon angioplasty, used to clear clogged blood vessels, is the most common medical intervention in the world. In an effort to improve on an angioplasty balloon currently on the market, extruded tubes were designed that were comprised of different numbers of layers of an 80/20 ratio of polyethylene terephthalate (PET) to a thermoplastic elastomer. Balloons were fabricated from these tubes, and tested for burst strength, puncture resistance, and compliance. Lastly, these properties were correlated to the material configuration of the balloons. It was found that, although the burst strength and compliance of the balloons was not significantly effected, increasing the number of layers while keeping the ratio of materials constant lead to a linear increase in the puncture resistance and toughness of the balloons. This is important because it shows that one of the angioplasty balloons currently sold can be improved simply by changing the configuration of the materials, instead of having to research new medical grade polymers and how to process them.

Restenosis is the major cause of the failure of reconstruction methods to restore the blood flow in atherosclerotic arteries. Restenosis results from neointima formation and consequent constrictive remodelling. Vascular smooth muscle cell (VSMC) migration from the tunica media toward the intima is crucial in neointima genesis. The prerequisite for VSMC migratory activity is the modulation from the differentiated (contractile) to the de-differentiated (noncontractile) phenotype. VSMC phenotype change is associated with the altered expression of integrins. alpha8beta1 integrin is upregulated in cell types with contractile properties, including myofibroblasts and mesangial kidney cells. It is one of the integrins that is intensely expressed in mature VSMCs. alpha8beta1 integrin expression during vascular injury and its role in VSMC function have not been studied so far. / In this work, a rat model of carotid angioplasty was used to mimic vascular injury in humans. alpha8beta1 integrin was downregulated in the tunica media concomitantly with loss of the contractile phenotype. In vitro study revealed that it is a differentiation marker of VSMCs. To test the functional significance of the association between alpha8 integrin and the VSMC phenotype, short interference RNA was deployed to silence the alpha8 integrin gene. alpha8 integrin gene silencing heightened VSMC migratory activity as well as modulation of the VSMC phenotype in favour of the noncontractile state. In addition, alpha8 integrin overexpression induced re-differentiation of VSMCs and attenuated their migratory activity. It is, therefore, suggested that alpha8 integrin overexpression after vascular injury might control VSMC migration and neointima formation. On the other hand, alpha8 integrin gene silencing led to a reduced growth rate, which indicated a dichotomy between VSMC migration and proliferation. / In the later stages of neointima formation, constrictive remodeling plays a major role in late lumen loss. Our data demonstrated that alpha8 integrin is upregulated in the neointima during constrictive remodeling with concomitant luminal narrowing. The importance of this finding was highlighted by results showing that alpha8 integrin was required for the VSMC contractile phenotype evoked by transforming growth factor-beta (TFG-beta) and TFG-beta-induced myofibroblastic differentiation of Rat1 fibroblasts. Thus, it appears that alpha8 integrin expression blockade might reduce contractile remodeling and late lumen loss. Although the mechanism of alpha8 integrin signaling is not yet clear, our findings demonstrate that the alpha8 integrin-induced contractile phenotype is blocked by RhoA inhibitors. Furthermore, alpha8 integrin and RhoA are co-immunoprecipitated, and alpha8 integrin gene silencing reduces RhoA activity. Hence, it is postulated that alpha8-RhoA signaling might be closely intertwined. / Altogether, these studies indicate that alpha8 integrin is a contractile marker of VSMCs and a negative regulator of VSMC migration. Therefore, forced alpha8 integrin expression may be applied to reduce neointima formation. However, alpha8 integrin upregulation during constrictive remodeling concomitant with late lumen loss suggest that it could be involved in lumen narrowing. It seems likely that in therapeutic strategies to reduce restenosis the timeline of interference might be very important. Therefore, alpha8 integrin gene silencing in the later stages of neointima formation might be beneficial.

No description available.

Thesis (M.S.)--University of Wisconsin-Madison, 1988. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves: 28-32).

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2005. / Härtill 4 uppsatser.

IntroduÃÃo: A prevenÃÃo da nefropatia induzida por contraste (NIC) à difÃcil nas situaÃÃes de emergÃncia tornando essenciais estudos sobre NIC em pacientes submetidos à angioplastia de urgÃncia. Objetivo: Determinar a incidÃncia e fatores associados à NIC em pacientes com infarto agudo do miocÃrdio (IAM) submetidos à angioplastia nas primeiras 12 horas apÃs inÃcio dos sintomas. MÃtodos: Foram estudados 201 casos consecutivos de IAM com supradesnivelamento do segmento ST com menos de 12 horas de evoluÃÃo. Todos os pacientes foram submetidos ao mesmo protocolo de angioplastia. A NIC foi definida como elevaÃÃo absoluta da creatinina de pelo menos 0,5 mg/dL e/ou aumento relativo da creatinina de 25% em relaÃÃo ao valor basal no perÃodo entre 48 e 72 horas apÃs a administraÃÃo do contraste. As variÃveis que diferiram entre os pacientes com e sem NIC na anÃlise univariada foram analisadas por regressÃo logÃstica. Resultados: A amostra foi formada por 135 (67,2%) homens e 66 (32,8%) mulheres com idade mÃdia de 66,6  11,7 anos. A incidÃncia de NIC foi de 23,8%. Na anÃlise univariada os pacientes com NIC eram mais idosos e com maior frequÃncia de fraÃÃo de ejeÃÃo do ventrÃculo esquerdo ≤ 40% e da classificaÃÃo Killip ≥ 2. Na anÃlise multivariada nÃo foram encontrados preditores independentes de NIC. ConclusÃo: A NIC acomete  dos pacientes com IAM submetidos à angioplastia sem variÃveis preditoras. Esse resultado ressalta a necessidade de medidas preventivas para NIC apÃs uso de contraste em angioplastia de urgÃncia. / Introduction: The prevention of contrast-induced nephropathy (CIN) is difficult in emergency situations, making it essential to study CIN in patients submitted to urgent angioplasty. Objective: To determine the incidence and associated factors to CIN in patients with myocardial infarction (MI) submitted to primary angioplasty in the first 12 hours after onset of symptoms. Methods: We studied 201 consecutive cases of MI with ST-segment elevation with less than 12 hours of evolution. All patients were submitted to the same angioplasty protocol. CIN was defined as an absolute increase of creatinine of at least 0.5 mg/dL and/or a relative increase of creatinine of 25% in relation to baseline in a period between 48 and 72 hours after contrast administration. The variables that differed between patients with and without CIN in univariate analysis were analyzed by logistic regression. Results: The sample was formed by 135 (67.2%) men and 66 (32.8%) women, with mean age of 66.6  11.7 years. The incidence of CIN was 23.8%. In univariate analysis the patients with CIN were older and had higher frequency of left ventricular ejection fraction ≤ 40% and Killip classification ≥ 2. In multivariate analysis, we did not find independent predictors of CIN. Conclusion: CIN occurred in  of the patients with MI submitted to angioplasty without predictor variables. This finding highlights the need for CIN preventive measures after contrast use in emergency angioplasty.

Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2016-05-20T11:04:08Z No. of bitstreams: 2 Dissertação - Rafaela BoaventuraDissertação - 2015.pdf: 2924130 bytes, checksum: 4e018286f98fb2207e11af7d96787837 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-05-27T11:08:32Z (GMT) No. of bitstreams: 2 Dissertação - Rafaela BoaventuraDissertação - 2015.pdf: 2924130 bytes, checksum: 4e018286f98fb2207e11af7d96787837 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-05-27T11:08:33Z (GMT). No. of bitstreams: 2 Dissertação - Rafaela BoaventuraDissertação - 2015.pdf: 2924130 bytes, checksum: 4e018286f98fb2207e11af7d96787837 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-03-23 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / This study aimed to analyze the pre-hospital course of patients undergoing percutaneous myocardial reperfusion in acute myocardial infarction and evaluate the performance of health care quality indicators of myocardial infarction in these patients. This is a retrospective cohort study with convenience sample. It was analyzed 39 cases of myocardial infarction with ST segment elevation, with Delta T up to 12 hours without previous administration of fibrinolytic agents, admitted for treatment at the General Hospital of Palmas / TO in 2013. Data were collected in the pre-hospital phase in records and interview and in the in-hospital phase through secondary data. For statistical analysis we used the Shapiro-Wilk test, Student's t test and ANOVA with 5% significance level. Most were male (76.9%), with a stable partner (74.4%), with up to nine years of education (64.1%) and at least three cardiovascular risk factors (79.5%). In the pre-hospital delta T phase was high (06h34min ± 03:14) and 10.2% achieved the recommended metric. The delta T was higher among patients that did not previously recognized symptoms of AMI (mean 07h09min ± 03h12min) and lower among those who were treated during the day (mean 03h 25min ± 05h35min). In-hospital phase, 56% were admitted during the day. In 30.8% of cases the Killip Kimball was > I. Among the other infarcted walls prevailed the bottom wall. Five patients (12.8%) died. Time door-ECG and needle holder did not follow international recommendations for all variables. The early recognition of symptoms and time of care are interfering for prehospital delay. There was no statistical correlation-balloon time and door-ECG door to the profile of patients with clinical variables in the hospitalization phase. The metric assessment of infarct treatment quality indicators in the acute phase was unsatisfactory throughout the study period. / Objetivou-se analisar a trajetória pré-hospitalar dos pacientes submetidos à reperfusão miocárdica percutânea na fase aguda do infarto do miocárdio e avaliar o desempenho dos indicadores de qualidade da atenção ao infarto do miocárdio desses pacientes. Trata-se de coorte retrospectiva, com amostra por conveniência. Foram analisados 39 casos de infarto do miocárdio com supradesnível do segmento ST, com Delta T até 12 horas e sem administração prévia de fibrinolíticos, admitidos para tratamento no Hospital Geral de Palmas / TO em 2013. Os dados foram coletados na fase pré-hospitalar por consulta em prontuário e entrevista; na fase intra-hospitalar, por meio de dados secundários. Para a avaliação estatística foram utilizados o teste de Shapiro-Wilk, o teste t de Student e ANOVA, com nível de significância de 5%. A maioria era do sexo masculino (76,9%), com companheiro estável (74,4%), com até nove anos de estudo (64,1%) e com pelo menos três fatores de risco cardiovasculares (79,5%). Na fase pré-hospitalar o Delta T foi elevado (06h34min ± 03h14min) e 10,2% atingiram a métrica recomendada. O Delta T foi maior entre os pacientes que não reconheceram previamente os sintomas de IAM (média 07h09min ± 03h12min) e menor entre aqueles que foram atendidos durante o dia (média 05h35min ± 03h 25min). Na fase intra-hospitalar, 56% foram admitidos durante o dia. Em 30,8% dos casos o Killip Kimball foi > I. Dentre as demais paredes infartadas prevaleceu a parede inferior. Cinco pacientes (12,8%) evoluíram para óbito. Os tempos porta-ECG e porta-agulha não seguiram as recomendações internacionais para todas as variáveis. O reconhecimento prévio dos sintomas e o horário do atendimento estão interferindo para o atraso pré-hospitalar. Não houve correlação estatística do tempo porta-balão e porta-ECG com o perfil dos pacientes e com as variáveis clínicas na fase intra-hospitalar. A avaliação métrica dos indicadores de qualidade do tratamento do infarto na fase aguda foi insatisfatória durante todo o período avaliado.