Arteries respond to changes in global mechanical parameters (pressure, flow rate, and longitudinal stretching) by remodeling to restore local parameters (circumferential stress, shear stress, and axial strain) to baseline levels. Because a change in a single global parameter results in changes of multiple local parameters, the effects of individual local parameters on remodeling remain unknown. This study uses a novel approach to study remodeling in organ culture based on independent control of local mechanical parameters. The approach is illustrated by studying the effects of circumferential and shear stress on remodeling-related biological markers. Porcine carotid arteries were cultured for three days at a circumferential stress of 50 kPa or 150 kPa or, in separate experiments, a shear stress of 0.75 Pa or 2.25 Pa. At high circumferential stress, matrix synthesis, smooth muscle cell proliferation, and cell death are significantly greater, but matrix metalloproteinase-2 (MMP-2) and pro-MMP-2 activity are significantly less. In contrast, biological markers measured were unaffected by shear stress. Applications of the proposed approach for improved understanding of remodeling, optimizing mechanical conditioning of tissue engineered arteries, and selection of experimentally motivated growth laws are discussed.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2006. / Härtill 4 uppsatser.

Objetivo: Avaliar a eficácia da ultrassonografia com contraste (US com contraste) de segunda geração no diagnóstico diferencial entre oclusão e pseudo-oclusão de artéria carótida interna cervical (ACI) comparativamente à ultrassonografia com Doppler (US Doppler) utilizando a angiotomografia computadorizada (angio-TC) como padrão-ouro. Materiais e Métodos: Estudo prospectivo realizado entre junho de 2006 e junho de 2008 com 72 pacientes sintomáticos (57; 15) e 78 com ACIs aparentemente ocluídas pela US Doppler. Esses pacientes foram submetidos inicialmente à US Doppler e, em seguida, à US com contraste. Todos os pacientes realizaram posteriormente a angio-TC, utilizada como padrão-ouro. A correlação entre os métodos foi feita através de estudo duplo cego. Resultados: A sensibilidade, a especificidade e a acurácia da US com contraste foram respectivamente de 100%; 90,5% e 97,4%. Quando comparada à angio-TC, a quantidade de falsas oclusões pela US Doppler foi de 26,9% (21/78), (p < 0,001), enquanto que pela US com contraste foi de 2,6% (2/78) (p = 0,500). A US com contraste obteve melhor resultado que a US Doppler, com diferença estatisticamente significante (p < 0,001). Conclusão: A US com contraste é tão eficaz quanto a angio-TC e superior à US Doppler no diagnóstico diferencial entre oclusão e pseudo-oclusão da ACI / Purpose: Evaluate the efficacy of second-generation contrast ultrasound (CEUS) for distinguishing the diagnosis of cervical internal carotid artery (ICA) occlusion from the one of pseudo-occlusion when compared with Doppler Ultrasound (DUS) utilizing computerized angiotomography (CTA) as the gold standard. Material and Methods: A prospective study was performed between June 2006 and June 2008 with 72 symptomatic patients (57 males; 15 females) and 78 ICAs apparently occluded by DUS. These patients were initially subjected to DUS and then to CEUS. All patients went through CTA later on, used as the gold standard. Correlation between the methods was made by means of a double-blind study. Results: The sensitivity, specificity and accuracy of CEUS were taken as 100%, 90.5% and 97.4% respectively. When compared with CTA the amount of false occlusions by DUS was 26.9% (21/78), (p < 0.001) whereas by CEUS 2.6% (2/78) (p = 0.500) was seen. Far better results were obtained with CEUS than with DUS with a significant discrepancy (p < 0.001). Conclusion: CEUS shows to be as effective as CTA but better than DUS for distinguishing the diagnosis of ICA occlusion from the one of pseudo-occlusion

Introdução: Os traumas arteriais e venosos são responsáveis por expressiva morbimortalidade, e, em determinados territórios, a técnica de restauração aberta acrescenta riscos elevados ao paciente, que podem ser minimizados com o uso de técnicas endovasculares. Objetivos: O objetivo deste estudo foi criar um modelo experimental de trauma vascular periférico penetrante em que se avalia a viabilidade do reparo endovascular em lesões da parede arterial com diferentes extensões cincunferenciais. Método: Vinte porcos brancos machos foram divididos em quatro grupos, de acordo com a extensão circunferencial do trauma arterial: sem lesão arterial (Grupo 1); lesão arterial com extensão circunferencial <50% (Grupo 2); lesão arterial com extensão circunferencial >50%, variando entre 50-80% (Grupo 3); e secção completa (Grupo 4). A artéria carótida comum esquerda foi dissecada com controle arterial proximal e distal, procedimento que se seguiu de secção controlada da parede arterial, fechamento dos planos e compressão manual por dez minutos, seguida de tratamento endovascular com introdução de stent revestido ViabahnTM (5mm x 50 mm) por via de acesso femoral. Resultados: A viabilidade e a reprodutibilidade do modelo experimental proposto foram confirmadas pelo sucesso no tratamento de todos os animais sem trauma e nos animais com lesões <50%. Sucesso da técnica endovascular também foi observado em quatro dos cinco animais com lesões >50% e, em um animal com secção completa. Variáveis como a duração do procedimento, parâmetros ultrassonográficos e arteriográficos, e flutuação dos sinais vitais foram devidamente monitoradas. Conclusões: O reparo endovascular do trauma arterial periférico em animais de experimentação mostrou-se factível com limitação dependendo da extensão circunferencial da lesão. Este modelo experimental, envolvendo técnicas endovasculares, indicou etapas importantes a serem consideradas em outros estudos nestes animais e com a utilização destes materiais. / Background: Additional surgical trauma often increases the risk of major morbidity and mortality associated with vascular injury, and endovascular repair could have many advantages in such situations. Objectives: The aim of this study was to create an experimental animal model of penetrating peripheral artery injury and to evaluate the feasibility of endovascular repair in different degrees of circumferential injury. Methods: Twenty white male domestic pigs were divided into four groups according to the circumferential extent of arterial injury: no injury; circumferential injury extent < 50% or > 50%, ranging between 50- 80%, and complete sectioning. Left common carotid artery was dissected with proximal and distal artery control followed by controlled section of the arterial wall. Local manual compression was applied for 10 minutes followed by endovascular treatment with a 5 x 50 mm ViabahnTM covered stent using the femoral approach. Results: The feasibility and reproducibility of the proposed experimental model was confirmed by the successful treatment of all animals with no injury and with injuries with a circumferential extent < 50%. Success was also achieved in four of the 5 animals in the group with injuries of circumferential extent > 50%, and in one pig in the complete section group. Additional variables were monitored, such as duration of procedure, ultrasound and arteriography parameters and fluctuation of vital signs. Conclusions: Endovascular repair of arterial injury is possible depending on circumferential extension of arterial lesion. This experimental model, involving endovascular techniques, shows important steps to consider in further studies in these animals and use of these materials.

Magister Scientiae (Medical Bioscience) - MSc(MBS) / Stroke is the third leading cause of death in South Africa, killing about 240 people a day and leaving survivors with residual disabilities. There is no clinically approved neuroprotective agent for stroke at the moment but the consumption of plant polyphenols has been suggested to offer neuroprotection against stroke and other neurodegenerative diseases. In this study, we investigated the effects of long term consumption of fermented rooibos herbal tea (FRHT) on ischemia reperfusion brain injury (I-RBI) in rats. Male adult Wistar rats were fed FRHT ad libitum for 7 weeks prior to the induction of ischemic injury by the transient bilateral occlusion of the common carotid arteries (BCCAO) for 20 minutes followed by 24 hours, 4 and 7 days of reperfusion respectively. Rats were then evaluated for neurologic deficits before sacrifice and brains harvested for assessment of brain oedema, blood-brain-barrier (BBB) integrity through Evans blue extravasation (EBE), immunohistochemical studies of apoptosis and lipid peroxidation. Oxygen radical antioxidant capacity and ferric reducing antioxidant power assays were also conducted to assess total antioxidant capacity after ischemia-reperfusion injury. Notably, the long term consumption of fermented rooibos herbal tea prevented brain oedema by reducing cerebral swelling induced by I-RBI. We also observed that fermented rooibos herbal tea offered neuroprotection against damage to the BBB and delayed neuronal death associated with BCCAO as fewer apoptotic cells were identified 7 days post BCCAO reperfusion. Significantly reduced levels of lipid peroxidation and increased levels of total antioxidant capacity were also observed in brain specimens of rats treated with FRHT. Rats treated with FRHT also showed improved neurologic outcomes when compared with the untreated animals. Our results show that FRHT has potent antioxidant and anti-inflammatory properties which can provide neuroprotective effects against neuronal cell loss, cerebral swelling, BBB disruption, lipid peroxidation and neurologic deficits following I-RBI. The use of FRHT is therefore highly recommended for patients with conditions that predispose them to stroke.

Orientador: Wilson Nadruz Junior / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-22T09:54:44Z (GMT). No. of bitstreams: 1 Gemignani_Tiago_D.pdf: 3089084 bytes, checksum: aedee263d43b0d61197caea8058ed566 (MD5) Previous issue date: 2013 / Resumo: As artérias dos membros inferiores são submetidas a uma maior sobrecarga hemodinâmica na posição ortostática. Este estudo avaliou os efeitos da variação postural sobre a tensão circunferencial na parede das artérias poplíteas, carótidas e braquiais, bem como investigou a correlação entre a tensão circunferencial e a presença de placas ateroscleróticas nestas artérias em uma população com fatores de risco cardiovascular. Duzentos e três indivíduos (118 mulheres e 85 homens) com fatores de risco cardiovascular (tabagismo, hipertensão arterial e diabetes mellitus) foram estudados clínica e laboratorialmente, sendo a pressão arterial mensurada nos braços e panturrilhas, tanto em posição supina como ortostática. As artérias foram avaliadas por ultrassonografia, enquanto a tensão circunferencial foi calculada de acordo com a Lei de Laplace. Nos indivíduos participantes, observou-se a presença de placas ateroscleróticas em 47%, 29% e 0% das artérias poplíteas, carótidas e braquiais, respectivamente. As medidas de tensão circunferencial em artérias carótidas não foram associadas à presença de placas ateroscleróticas após ajuste pelas variáveis confundidoras. Por outro lado, as análises de regressão logística e de modelo linear geral mostraram, após ajuste pelas variáveis confundidoras, que a tensão circunferencial sistólica ortostática foi o único parâmetro hemodinâmico local que demonstrou correlação significativa com placas ateroscleróticas poplíteas em toda amostra estudada. Na análise específica por sexos, apesar da correlação positiva com a presença de placas ateroscleróticas poplíteas em ambos os sexos, a tensão circunferencial sistólica ortostática exibiu associação independente com placas ateroscleróticas somente em mulheres, após ajuste pelas variáveis confundidoras. Em conclusão, a tensão circunferencial ortostática poplítea e não a em posição supina, é associada com placas ateroscleróticas em artérias poplíteas, particularmente em mulheres. Estes dados sugerem que a posição ortostática pode desempenhar uma função importante na aterogênese das artérias dos membros inferiores, modificando as forças hemodinâmicas locais, podendo, contudo, haver diferença entre os sexos / Abstract: Lower limb arteries are exposed to higher hemodynamic burden in erectile posture. This study evaluated the effects of body posture on popliteal, carotid and brachial circumferential wall tension (CWT) and investigated the relationship between local CWT and atherosclerotic plaques in subjects with cardiovascular risk factors. Two hundred and three subjects (118 women and 85 men) with cardiovascular risk factors (smoking, hypertension or diabetes mellitus) underwent clinical and laboratory analysis and had their blood pressure measured in the arm and calf in supine and orthostatic positions. Arteries were evaluated by ultrasound analysis, while CWT was calculated according to Laplace's law. Among the enrolled participants, 47%, 29% and none presented popliteal, carotid and brachial plaques, respectively. Carotid CWT measurements were not associated with local plaques after adjustment for potential confounders. Conversely, general linear model and logistic regression analyses adjusted for potential confounders demonstrated that peak orthostatic CWT was the only local hemodynamic parameter showing significant relationship with popliteal plaques in the whole sample. In gender-specific analyses, although positively correlated with popliteal plaques in both genders, local peak orthostatic CWT exhibited an independent association with popliteal plaques after adjustment for potential confounders only in women. In conclusion, popliteal CWT measured in orthostatic posture, rather than in supine position, is associated with popliteal atherosclerotic plaques, particularly in women. These findings suggest that orthostatic posture might play a role in the atherogenesis of leg arteries by modifying local hemodynamic forces and that there may be gender differences in this regard / Doutorado / Clinica Medica / Doutor em Clínica Médica

Orientador: Marcio Ajudarte Lopes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-28T00:44:23Z (GMT). No. of bitstreams: 1 LucenaMarkman_Renata_M.pdf: 960885 bytes, checksum: 639bd2b482bba1e49ed3111595f8f4da (MD5) Previous issue date: 2015 / Resumo: Estudos sugerem que o tratamento radioterápico em região de cabeça e pescoço possa ser considerado um importante fator desencadeador da formação de calcificações em carótida. No entanto, evidências científicas para tal comprovação são limitadas. Portanto, os objetivos deste estudo foram identificar através de radiografias panorâmicas a prevalência de ateromas calcificados da carótida numa população com câncer de cabeça e pescoço antes e depois de serem submetidos à radioterapia e correlacionar com os aspectos sócio-demográficos e comorbidades destes pacientes. Foram selecionados, de forma retrospectiva, 180 pacientes tratados por radioterapia que tinham radiografias panorâmicas realizadas antes e após o término deste tratamento. Os dados clínicos foram coletados dos prontuários médicos. A análise das radiografias panorâmicas mostrou que 35% dos pacientes apresentaram ateromas calcificados da carótida. Não foi encontrada diferença significativa na prevalência de ateromas antes e após a radioterapia. Com relação aos achados clínicos, houve maior prevalência de acidentes vasculares cerebrais em pacientes com ateromas quando comparados aos pacientes que não apresentaram ateromas (p<0,05). Não foram observadas outras diferenças significativas com relação à idade, gênero, hipertensão arterial, diabetes mellitus, infarto agudo do miocárdio, localização do tumor e dose de radiação recebida. Sendo assim, podemos concluir que apesar da radioterapia não ter modificado a prevalência de ateromas calcificados da carótida nesta população estudada, esta alteração é frequentemente encontrada em pacientes com câncer de cabeça e pescoço. Portanto, é importante que os cirurgiões-dentistas fiquem atentos quanto à presença de ateromas em radiografias panorâmicas de pacientes com câncer de cabeça e pescoço / Abstract: Studies suggest that radiotherapy to the head and neck may be an important triggering factor for calcified carotid artery atheromas. However, scientific evidences to prove this matter are limited. Therefore, this essay aimed to identify the prevalence of calcified carotid artery atheromas observed by panoramic radiograph in a head and neck cancer population before and after radiotherapy and to correlate them with the sociodemographic features and comorbidities of these patients. For this research, 180 patients submitted to radiotherapy that had panoramic radiographs before and after this treatment, were selected retrospectively. Clinical data from these patients were collected from their medical records. The panoramic radiographs were examined and 35% of the patients demonstrated calcified carotid artery atheromas. There was no significant difference in the prevalence of atheromas before and after radiotherapy. According to clinical data, there was a greater prevalence of strokes in patients with calcified carotid artery atheromas when compared to patients who did not have atheromas (p<0.05). Differences related to age, gender, arterial hypertension, diabetes mellitus, acute myocardial infarctation, tumor location and radiotherapy dose were not observed. Thus, we can conclude that although radiotherapy did not alter the prevalence of calcified carotid artery atheromas in the studied population, this alteration is commonly found in head and neck cancer patients. Therefore, it is important that dentists be aware to the presence of calcified carotid artery atheromas in panoramic radiographs of head and neck cancer patients / Mestrado / Estomatopatologia / Mestra em Estomatopatologia

Orientador: Ana Terezinha Guillaumon / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-28T09:17:18Z (GMT). No. of bitstreams: 1 Siqueira_LeticiaCristinaDalledone_M.pdf: 5041737 bytes, checksum: 615b5b4269f2f46490565662d28dfb21 (MD5) Previous issue date: 2015 / Resumo: Introdução: A espectroscopia próxima ao infra-vermelho (NIRS) é uma técnica não invasiva e de baixo custo que detecta as alterações hemodinâmicas teciduais. O NIRS pode monitorar de forma contínua as informações fisiológicas vasculares intracranianas. Por ser portátil, ele pode ser utilizado a beira do leito e no centro cirúrgico. Objetivo: Avaliar o comportamento das possíveis alterações hemodinâmicas cerebrais, durante a endarterectomia, em pacientes com estenoses maiores que 70%, utilizando NIRS. Casuística e métodos: Foram avaliados 10 voluntários portadores de doença carotídea aterosclerótica com indicação de endarterectomia. Após a seleção dos pacientes que responderam um questionário com dados epidemiológicos e informações referentes a presença de comorbidades, a doença foi confirmada por métodos diagnósticos. No procedimento cirúrgico utilizou-se o NIRS para monitorização. Foram avaliadas as variáveis saturação de oxigênio (Sat O2) hemoglobina total (HbT), hemoglobina reduzida (HbR) e hemoglobina oxigenada (HbO) nos três tempos cirúrgicos pré, trans e pós-clampeamento carotídeo. Resultados: Utilizou-se p<0,05 como nivel de significância. A avaliação dos resultados obtidos através das medidas registradas pelo NIRS permite afirmar que as etapas da cirurgia diferem quanto ás variável HbR e SatO2. Durante a etapa do clampeamento, a variável HbR mostra valores mais elevados que nas outras duas etapas da cirurgia. De outra parte, a variável SatO2 mostra redução durante o clampeamento. Conclusão: O NIRS é um método viável e aplicável de monitorização intracerebral, não-invasivo e em tempo real, durante a endarterectomia carotídea, capaz de medir de forma precisa as mudanças das condições hemodinâmicas capilares intra-cerebrais / Abstract: Introduction: Near-infrared spectroscopy (NIRS) is a low-cost, non-invasive technique that detects tissue hemodynamic alterations. It enables continuous monitoring of the intracerebral vascular physiologic information. Due to its portable nature, NIRS may be used beside a bed or in the operating room. Objective: To evaluate the use of NIRS for intra-surgical monitoring of the brain hemodynamic response, during an endarterectomy procedure of the atherosclerotic carotid artery. Casuistry and Methods: 10 patients with atherosclerotic carotid disease and recommended endarterectomy were evaluated. They were identified in a survey which provided epidemiologic data and the presence of comorbidities. Disease was confirmed by diagnostic methods. NRIS monitoring was used during the surgical procedure. Oxygen saturation (O2 Sat), total hemoglobin (THb), reduced hemoglobin (RHb), and oxyhemoglobin (OHb) were the variables analyzed at the three carotid clamp stages: pre-, trans- and post-. Results: A p<0.05 value was considered statistically significant. The results obtained from the NIRS data reveal that the surgical stages differ in relation to the RHb and O2Sat variables. RHb presents higher levels during clamping when compared with the other two surgical stages. On the other hand, O2Sat is decreased during clamping. Conclusion: NIRS is a feasible, realtime and non-invasive intracranial monitoring method, during carotid endarterectomy, which measures accurately and reliably the changes of the intracerebral capillary hemodynamic conditions / Mestrado / Cirurgia / Mestra em Ciências

This master's thesis deals with pulsating flow of Newtonian and non-Newtonian fluid. Theoretical part represents necessary theoretical knowledge for pulsating flow and understanding of non-Newtonian behaviour. Furthermore the thesis focus is directed on numerical simulation of pulsating flow in straight, ideally rigid tube and in patient-specific model of human artery, more precisely in carotid. Two methods are used: numerical solution based on finite volume method (FVM) and also analytical solution using Bessel functions by Womersley. Results are validated against experimental measurements of velocity profiles by particle image velocity method (PIV). The agreement between numerical and experimental data with consideration of PIV inaccuracy was was very good from both point of views - qualitative and quantitative. Numerical solution also compare influence of turbulence and non-Newtonian behaviour towards base (laminar flow, Newtonian fluid). Developed methodology is then applied on patient-specific model of carotid, which was renovated from computed tomography. Measurements in vivo in human arteries is very expensive and often invasive. Because of that measurement outputs are limited, most of the time on pressure and flow. Computational fluid dynamics (CFD) is non-invasive and outputs are through whole domain. Due to these advantages CFD significantly contributes to understanding of hemodynamics influence in cardiovascular diseases.

Unterschiedliche zerebrale Protektionssysteme zur Verhinderung neurologischer Ereignisse während einer Karotis-Angioplastie sind derzeit im Einsatz. Dennoch zeigen Studien, dass diese Systeme die distale Mikroembolisation während der Intervention nicht vollständig verhindern können. Die vorliegende Arbeit vergleicht die Effektivität von zwei verschiedenen Protektionssystemen unter Anwendung der Methode der transkraniellen Dopplersonographie (TCD). Es wurden 42 Patienten mit einer hochgradigen Stenose der A. carotis interna während der Karotisangioplastie mit Stentimplantation untersucht. Zur Neuroprotektion wurde entweder ein Filtersystem (E.P.I. FilterWireTM, Boston Scientific, USA) oder ein proximales Ballonokklusionssystem (MO.MA-System Invatec, Italien) verwendet. Bei jedem Patienten erfolgte während der Intervention mittels TCD die Detektion der mikroembolischen Signale (MES). Die Anzahl der MES wurde während fünf verschiedener Prozedurphasen gezählt und miteinander verglichen. Die Ergebnisse der Arbeit zeigen, dass die Karotis-Angioplastie unter Schutz des MO.MA-Systems vor allem in den Phasen der Passage der Stenose, der Stentimplantation und der Nachdilatation mit signifikant niedrigeren MES assoziiert war, verglichen zur Angioplastie der A. carotis interna unter einem Filtersystem.