INTRODUÇÃO: Dentre os mecanismos de ação da pressão negativa no tratamento de feridas, que não são totalmente compreendidos até o momento, a melhora do fluxo sanguíneo local pode ser um dos mais importantes. A melhora da circulação sanguínea local promovida pela pressão negativa poderia resultar em maior sobrevida de tecidos submetidos a redução do fluxo sanguíneo. A aplicação clínica deste fenômeno seria um dos mecanismos de ação mais importantes da pressão negativa no tratamento de feridas complexas, e poderia ainda levar à utilização do método em outras situações clínicas, como em ferimentos descolantes de extremidades, e no salvamento de retalhos cutâneos mal perfundidos. OBJETIVO: Baseado na teoria de aumento do fluxo sanguíneo submetido a pressão negativa, este trabalho tem como objetivo avaliar a eficiência da pressão negativa na sobrevivência de retalhos cutâneos ao acaso, em suínos. MATERIAL E MÉTODO: Foram utilizados dez animais, divididos em dois grupos experimentais. No primeiro grupo, foram elevados dois retalhos cutâneos no dorso dos animais, um em cada lado, medindo 3 x 12 cm. Em um dos lados, foi aplicada pressão negativa de 125 mmHg por 48 horas sobre o retalho; no retalho contralateral (controle), o retalho foi apenas elevado e suturado novamente ao leito. No segundo grupo, foram também elevados dois retalhos cutâneos, um em cada lado, porém a pressão negativa foi aplicada abaixo dos retalhos no lado experimental; da mesma forma como no primeiro grupo, o outro lado contralateral foi o controle deste grupo (retalho apenas elevado e suturado ao leito). Também neste grupo a pressão negativa foi aplicada por 48 horas. Os animais dos dois grupos experimentais foram mantidos por sete dias, quando foi realizada a observação final. RESULTADOS: Ao final do experimento, foi observada maior quantidade de tecido viável e menor necrose distal dos retalhos no segundo grupo (pressão negativa abaixo dos retalhos), comparativamente ao seu grupo controle, nos dois períodos observacionais, com 48 horas e com sete dias. Não houve diferença estatisticamente significativa no grupo em que a pressão negativa foi aplicada sobre os retalhos. CONCLUSÃO: Este trabalho demonstrou a eficiência da pressão negativa na melhora da sobrevivência de retalhos cutâneos ao acaso, em modelo experimental de suínos, quando aplicada abaixo dos retalhos / INTRODUCTION: Among theories that could explain the mechanisms of action of negative pressure on wound treatment, which are not entirely understood, improvement of blood circulation can be one of the most important ones. The enhancement of blood flow could result in better outcome of tissues submmitted to ischemia. Clinical application of this phenomenom may be one of the most importante mechanisms of action of negative pressure over complex wounds, and could lead to its use in other clinical situations, such as \"degloving\" injuries of limbs and in salvage of poorly irrigated skin flaps. OBJECTIVE: Based on theory of improved blood flow caused by negative pressure, this experiment aimed to evaluate efficiency of negative pressure on survival of random skin flaps, in a swine experimental model. MATERIAL AND METHOD: Ten animals were operated on, and divided in two groups. In the first group, two skin flaps were dissected and elevated, one on each side of dorsum of the animals, measuring 3 x 12 cm. Negative pressure of 125 mmHg was applied over one of the flaps for 48 hours. The opposite flaps were just elevated and sutured to the wound bed, in order to be the control group. In the second group, two flaps were also elevated, one in each side of dorsum, but negative pressure was applied under the flaps in the experimental side; flaps elevated on the other side were the control group, just elevated and sutured to the wound bed. Negative pressure was also applied for 48 hours in the second group. All animals were kept alive for seven days, when final evaluation was done. RESULTS: At the end of the experiment, it was observed greater amount of viable tissue in group submmited to negative pressure under the flaps, compared to control group. There were no significant estatistical differences concerning flap survival in group 1 (negative pressure over flaps). CONCLUSION: This experiment demonstrated the efficiency of negative pressure on improvement of survival of random skin flaps in a swine experimental model, when applied under the flaps

O objetivo do estudo foi avaliar, por meio da ultrassonografia bidimensional e da ultrassonografia Doppler, as inter-relações entre a alteração de espessura do coxim digital com os índices vasculares da artéria digital dorsal comum dos membros pélvicos dos bovinos. A avaliação ultrassonográfica Doppler é uma técnica não invasiva de avaliação de índices vasculares, assim como, indiretamente, do volume de sangue do leito vascular. Para isso, foram realizados exames ultrassonográficos da espessura do coxim digital e também avaliação ultrassonográfica Doppler da referida artéria de 13 vacas primíparas da raça Holandesa, em intervalos de 14 dias, durante 126 dias após o parto. Ao longo do experimento o coxim digital apresentou diminuição não significativa de espessura (p=0,1715) e apresentou forte correlação positiva com a média do escore de condição corporal (p=0,03, r=0,71). Ao longo do período avaliado, o fluxo de sangue aumentou significativamente (p<0,0001) e apresentou correlação negativa com os índices que denotam impedância ao deslocamento de sangue, isto é, índice de resistividade (p<0,0001, r=-0,34911) e pulsatilidade (p<0,0001, r=-0,5035). Além disso, realizou-se correlação entre a diferença diária do fluxo de sangue e a diferença da espessura do coxim digital para cada animal e constatou-se uma forte tendência à correlação entre as diferenças das variáveis (p=0,0515, r=-0,5729). Por meio dos resultados encontrados foi possível concluir que o escore de condição corporal teve forte correlação com a espessura do coxim digital, ao longo do estudo. Além disso, o fluxo de sangue, os índices referentes à velocidade de deslocamento das hemácias e o diâmetro da artéria aumentaram ao longo do trabalho. E, também, que a discreta diminuição do coxim digital não foi um fator que influenciou no aumento do fluxo de sangue e nos índices vasculares / The aim of this study was to evaluate, by bidimensional and pused Doppler ultrasound, the interrelationship between the changes of the thickness of digital cushion with vascular indices of the common dorsal digital artery of the hind limbs of cattle. Pused Doppler sonography is a non-invasive tool to assessment the vascular indices, as well as, the blood flow volume in vascular bed. So, were performed ultrasound exams of soft tissue thickness and also the Doppler ultrasonographic evaluation of that artery in thirteen first lactation Holstein cows and followed them up during 126 days in milk. Throughout the experiment the digital cushion showed a slight decrease without significance (p=0,1715), this also was strongly correlated with body condition score (p=0,03, r=0,71). The blood flow volume had significance increase (p<0,0001) and was negatively correlated with both impedance indices, resistance index (P<0,0001 r =-0,34911) and pulsatility index (p <0,0001 r =-0,5035). In addition, a correlation was performed with both daily differences of the blood flow and the thickness of the digital cushion for each animal and it was observed a strong tendency of correlation between the different variables (p=0,0515 r =-0,5729). Therefore, we can conclude that body condition score was strong correlated with the thickness of digital cushion, throughout the study. In addition, the blood flow volume, the velocity indices and the artery diameter increase throughout the days in milk. And, so, the slight decrease in the thickness of digital cushion was not a factor that influenced the increase of blood flow and vascular indices

New optical technologies were developed to continuously measure cerebral blood flow (CBF) and oxygen metabolism (CMRO2) non-invasively through the skull. Methods and devices were created to improve the performance of near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS) for use in experimental animals and humans. These were employed to investigate cerebral metabolism and cerebrovascular reactivity under different states of anesthesia and during models of pathological states. Burst suppression is a brain state arising naturally in pathological conditions or under deep general anesthesia, but its mechanism and consequences are not well understood. Electroencephalography (EEG) and cortical hemodynamics were simultaneously measured in rats to evaluate the coupling between cerebral oxygen metabolism and neuronal activity in the burst suppressed state. EEG bursts were used to deconvolve NIRS and DCS signals into the hemodynamic and metabolic response function for an individual burst. This response was found to be similar to the stereotypical functional hyperemia evoked by normal brain activation. Thus, spontaneous burst activity does not cause metabolic or hemodynamic dysfunction in the cortex. Furthermore, cortical metabolic activity was not associated with the initiation or termination of a burst. A novel technique, time-domain DCS (TD-DCS), was introduced to significantly increase the sensitivity of transcranial CBF measurements to the brain. A new time-correlated single photon counting (TCSPC) instrument with a custom high coherence pulsed laser source was engineered for the first-ever simultaneous measurement of photon time of flight and DCS autocorrelation decays. In this new approach, photon time tags are exploited to determine path-length-dependent autocorrelation functions. By correlating photons according to time of flight, CBF is distinguished from superficial blood flow. Experiments in phantoms and animals demonstrate TD-DCS has significantly greater sensitivity to the brain than existing transcranial techniques. Intracranial pressure (ICP) modulates both steady-state and pulsatile CBF, making CBF a potential marker for ICP. In particular, the critical closing pressure (CrCP) has been proposed as a surrogate measure of ICP. A new DCS device was developed to measure pulsatile CBF non-invasively. A novel method for estimating CrCP and ICP from DCS measurement of pulsatile microvascular blood flow in the cerebral cortex was demonstrated in rats. / 2018-03-08T00:00:00Z

As reações de alerta e defesa compreendem ajustes cardiovasculares proporcionando um fluxo sangüíneo muscular adequado nas situações de \"luta ou fuga\". As vias centrais e os possíveis neurotransmissores envolvidos nestes ajustes permanecem ainda, em grande parte, desconhecidas. Neste estudo buscamos analisar a participação da neurotransmissão purinérgica e glutamatérgica no núcleo do trato solitário (NTS) na gênese da vasodilatação muscular durante reações de defesa e o papel das vias glutamatérgicas do NTS para o núcleo rostroventrolateral (RVL) nestas respostas. Ratos Wistar machos (250-350 g) foram anestesiados (uretana 600 mg/kg + alpha-chloralose 50 mg/kg, i.v.), paralisados (d-Tubocurarina, 0,5 mg/kg, i.v.) e ventilados artificialmente. Registramos a pressão arterial média (PAM), a freqüência cardíaca (FC) e o fluxo sangüíneo dos membros posteriores (FSMP). A condutância vascular dos membros posteriores (CVMP) foi determinada como a razão FSMP/PAM e expressa como percentagem do valor basal. A estimulação elétrica (EE; 150 MuA; 0,6 ms; 100 Hz; 6 s) do hipotálamo lateral provocou hipertensão, taquicardia e vasodilatação nos membros posteriores. A microinjeção bilateral de suramin (100 pmol/50 nl), um antagonista não específico de receptores P2x no NTS, reduziu a vasodilatação nos membros posteriores durante a EE do hipotálamo (173±19,0 vs 28±14,1% do basal) sem alterar as respostas pressora e taquicárdica. A microinjeção do agonista P2x alpha, beta-methylene ATP (100 pmol/50 nl) no NTS produziu hipotensão, bradicardia e vasodilatação dos membros posteriores. A microinjeção de suramin (100 pmol/50 nl) bloqueou a vasodilatação muscular (76±15,2 vs 9±2,1% do basal) e a hipotensão (-47±4,5 vs -6±2,0 mmHg). A microinjeção de ácido quinurênico (4 nmol/50 nl), um antagonista glutamatérgico ionotrópico não seletivo no NTS bloqueou, de forma semelhante ao suramin, a vasodilatação durante a EE do hipotálamo (134±21,5 vs 27±12,7% do basal) sem alterar as respostas pressora ou taquicárdica. O bloqueio bilateral no RVL com microinjeções de ácido quinurênico reduziu intensamente a resposta hipotensora (-60±6,1 vs -9±3,7 mmHg) e vasodilatadora (126±16,9 vs 17±4,6% do basal) provocada pelas microinjeções de alpha, beta-methylene ATP (100 pmol/50 nl) no NTS. O agonista purinérgico A2a, CGS21680 (20 pmol/50 nl) no NTS, evocou hipotensão, bradicardia e vasodilatação muscular de longa duração. O bloqueio do RVL com ácido quinurênico (4 nmol/50 nl) reduziu a hipotensão (- 41±4,7 vs -7±1,9 mmHg), a bradicardia (-33±9 vs -10±3,1 bpm) e a vasodilatação nos membros posteriores (81±5,6 vs 8±1,5% do basal). Estes resultados sugerem que a vasodilatação muscular nas repostas de defesa depende da ativação de receptores P2x e receptores glutamatérgicos no NTS. Ajustes cardiovasculares por ativação dos receptores purinérgicos P2x e A2a no NTS provocam vasodilatação muscular que depende da liberação de glutamato no RVL, provavelmente ativando interneurônios inibitórios ali presentes. / The electrical stimulation (ES) of the hypothalamus in the rat produces a well- defined pattern of cardiovascular adjustments including hypertension, tachycardia and skeletal muscle vasodilation. These hemodynamic responses can also be observed in natural conditions during fight and/or flight behaviors. However the neural pathways and possible neurotransmitters involved remain largely unknown. In this study we sought to determine the role of purinergic and glutamatergic receptors into the nucleus tractus solitarius (NTS) in the cardiovascular responses induced by hypothalamic ES, also we aimed to analyze the role of glutamatergic neural pathways from the NTS to the rostral ventrolateral medulla (RVLM) in these responses. Male Wistar rats (250-350 g) were anesthetized (urethane 600 mg/kg + alpha-chloralose 50 mg/kg, iv), paralyzed (d-tubocurarine 0.5 mg/kg, iv) and artificially ventilated. Mean arterial blood pressure (MAP), heart rate (HR) and hindquarter blood flow (HQBF) were recorded. Hindquarter vascular conductance (HQVC) was calculated as the ratio HQBF/MAP and expressed as percentage of baseline. Hypothalamic ES (6s trains, 0.6 ms square pulses, 100 Hz, 150 MuA) evoked a transitory hypertension, tachycardia and hindlimb muscle vasodilation. After bilateral microinjections of suramin (100 pmol /50 nl), a non-specific P2x receptor antagonist, into the NTS the hindlimb vasodilation was reduced (173±19.0 vs 28±14.1% of baseline), even so the transitory hypertension and tachycardia remained unchanged. A similar vasodilation reduction (134±21.5 vs 27±12.7% of baseline) was observed after microinjections of kynurenic acid bilaterally at the same NTS sites. Microinjections of the P2x receptor agonist alpha, beta-methylene ATP (100 pmol/50 nl) into the NTS produced hypotension, bradycardia and hindlimb muscle vasodilation. Bilateral microinjections of suramin at the same NTS site reduced the hypotension (-47±4.5 vs -6±2.0 mmHg) and the vasodilation (76±15.2 vs 9±2.1% of baseline). After bilateral microinjection of kynurenic acid into the RVLM, both hypotension (-60±6.1 vs -9±3.7 mmHg) and the vasodilation response (126±16.9 vs 17±4.6% of baseline) induced by alpha, beta- methylene ATP into the NTS were reduced. The A2a agonist CGS21680 (20 pmol/50 nl) into the NTS produced a long-lasting hypotension, bradycardia and hindlimb vasodilation. Bilateral RVLM glutamatergic blockade reduced the hypotension (-41±4.7 vs -7±1.9 mmHg), the tachycardia (-33±9.0 vs -10±3.1 bpm) and the muscle vasodilation (81±5.6 vs 8±1.5% of baseline) when CGS21680 was injected into the NTS. Therefore the results suggest that in alerting defense reaction, hindquarter vasodilation is mediated by NTS P2x and also by glutamatergic receptors into the intermediate NTS. Cardiovascular responses evoked by either P2x or A2a receptors stimulation in the NTS are mediated by glutamatergic synapses into the RVLM probably through activation of inhibitory interneurones in this area.

The study of non-Newtonian flow is presents itself as relevant in bioengineering field, specially for design of devices that conduct blood, as arterial bypass grafts. Improvements in reducing energy dissipation and blood cell damage caused by artificial flows can be achieved by using numerical simulation and optimization methods. Thus, the present work proposes the study of design channels for steady, incompressible non-Newtonian flow, by using Topology Optimization Method based on the density method. The fluid flow is modeled with the Navier-Stokes equations coupled with Carreau-Yasuda constitutive equation for the dynamic viscosity to take into account the effects of the non-Newtonian blood properties. The Topology Optimization Method distributes regions of solid and fluid, given a volume constraint, within a specified domain in order to obtain a geometry and layout that minimizes energy dissipation, shear stress and vorticity by using the material pseudo-density as design variable. To apply this method to fluidic systems design, a fictional porous media based on Darcy equation is introduced. The flow model is implemented in its discrete form by using the Finite Element Method through the OpenSource platform FEniCS, applied to automate the solution of mathematical models based on differential equations. The optimization problem is solved by using the library DOLFIN-adjoint and IPOpt optimizer. Optimized topologies of channels for blood flow, focusing in arterial bypass grafts, are presented to illustrate the proposed method. / O estudo de escoamento de fluidos não-Newtonianos apresenta-se relevante no campo de bioengenharia, em especial no projeto de dispositivos para condução de sangue, como bypass arterial. Melhorias na redução de dissipação de energia e no dano às células sanguíneas causados por fluxos artificiais podem ser obtidas através do uso de técnicas de simulação e otimização numéricas. Deste modo, este trabalho propõe o estudo do projeto de canais para escoamentos incompressíveis em regime permanente de fluidos não-Newtonianos através do Método de Otimização Topológica baseado no método de densidade. O escoamento é modelado com as equações de Navier-Stokes acopladas com a equação constitutiva de Carreau-Yasuda para a viscosidade dinâmica, para que sejam considerados os efeitos das propriedades não-Newtonianas do sangue. O Método de Otimização Topológica distribui regiões de sólido e fluido, dada uma restrição de volume, dentro de um domínio especificado de modo a obter uma geometria e configuração que minimize a dissipação de energia, tensão de cisalhamento e vorticidade, utilizando a pseudo-densidade do material como variável de projeto. Para aplicar este método a sistemas fluidos, um meio poroso fictício, baseado na equação de Darcy, é introduzido. O modelo de escoamento é implementado em sua forma discreta utilizando o Método de Elementos Finitos através da plataforma OpenSource FEniCS, aplicada para automatizar a solução dos modelos matemáticos baseados em equações diferenciais, e o problema de otimização é resolvido utilizando a biblioteca DOLFIN-adjoint e otimizador IPOpt. Topologias otimizadas de canais para fluxo de sangue, com foco em bypass arterial, são apresentadas para ilustrar o método proposto.

Background: Inadequate foetal growth cannot be remedied postnatally, leading to severe consequences for neonatal and adult development. Furthermore, sexual dimorphism in placental development has been suggested in humans although this remains poorly investigated in the pig. Hypotheses: Intrauterine Growth Restriction (IUGR) occurs due to aberrant conceptus attachment, which leads to alterations in angiogenesis and vascularity of the feto-maternal interface. Altered gene expression and vascularity will be observed at the feto-maternal interface in male foetuses compared to female foetuses. Increased apoptosis and decreased proliferation will be observed in the feto-maternal interface associated with the lightest foetuses compared to the closest to mean litter weight (CTMLW) foetuses. Aims: This thesis aimed to investigate the association between foetal size and sex and: integrin signalling; apoptotic and proliferation pathways; umbilical arterial (UA) blood flow; and angiogenesis and vascularity at the feto-maternal interface. This was performed by the collection of placental and endometrial samples associated with conceptuses or foetuses of different size (lightest and CTMLW) and sex at gestational day (GD) 18, 30, 45, 60 and 90. Conclusion This thesis has presented novel findings of associations between foetal size and sex, and placental and endometrial integrin signalling, apoptosis and proliferation, and angiogenesis and vascularity. Currently, this is the first suggestion in the literature that foetal size, and more intriguingly foetal sex, may have a strong influence on the activity of the endometrium. The mechanisms behind these findings warrant further investigation. Switches in the direction of differences at the feto-maternal interface between foetuses of different size were observed throughout gestation, notably between GD45 and 60, highlighting the dynamic nature of the feto-maternal interface and suggesting this as a potential window that could be manipulated by the industry to attempt to rescue the postnatal phenotype of IUGR piglets.

INTRODUÇÃO: Frente às evidências de que a depressão associa-se a eventos cardíacos, morte súbita, desenvolvimento de coronariopatia, e maior mortalidade por causas cardiovasculares, torna-se muito importante estudar as possíveis causas das alterações cardiovasculares na depressão. Alterações de sistema nervoso autonômico (SNA) vêm sendo descritas em pacientes deprimidos. Os estudos sobre funcionamento do SNA têm utilizado a dosagem de catecolaminas séricas e urinárias e análise de VFC, que são avaliações indiretas do funcionamento do SNA. Avaliações diretas, como a microneurografia, aparentemente ainda não foram utilizadas no estudo do funcionamento do SNA em pacientes com depressão maior. MÉTODOS: Neste estudo o comportamento do sistema nervoso simpático em indivíduos deprimidos, em período basal e após teste de estresse mental, foi comparado com controles. Realizaram as avaliações: 19 pacientes com depressão maior e 15 controles, com 18 a 45 anos de idade. Indivíduos que apresentassem condições médicas e/ou uso de medicamentos que pudessem interferir com o comportamento do sistema nervoso autonômico não foram incluídos. A avaliação psiquiátrica incluiu a administração da Escala de avaliação para depressão de Montgomery e Asberg (MADRS) e Entrevista Clínica Estruturada para o DSM-IV - Transtornos do Eixo I - Versão 2.0 (SCID-I /P). Atividade nervosa simpática muscular (ANMS) foi medida pela microneurografia. Fluxo sangüíneo muscular (FSM) no antebraço foi medido pela técnica de peltismografia de oclusão venosa. A pressão arterial (PA) foi monitorizada de forma não invasiva por um manguito inflado automaticamente, e a freqüência cardíaca (FC) foi medida por eletrocardiograma. O registro basal foi realizado por 3 minutos, seguido de teste de cores, que foi realizado por 4 minutos. RESULTADOS: Os grupos de pacientes deprimidos e controles não diferiram significativamente em relação a idade, peso e índice de massa corpórea. Os grupos de pacientes deprimidos e controles não apresentaram diferenças significativas nos valores de ANSM, PA sistólica, PA diastólica, PA média, FC, FSM e condutância vascular no antebraço no período basal. Não houve diferença significativa na reatividade ao estresse mental entre os grupos. Houve correlação positiva e significativa (0,84; p=0,0001) entre os valores de MADRS e de ANSM média no período basal dos pacientes com depressão. Houve correlação positiva e significativa (0,70; p=0,01) entre os valores do item tensão da MADRS e de ANSM média no período basal dos pacientes com depressão. CONCLUSÕES: Não foram encontradas diferenças nas medidas basais de atividade simpática entre indivíduos deprimidos e controles. Também não foram encontradas diferenças na reatividade cardiovascular a teste de estresse mental entre os grupos. Houve uma correlação positiva e significativa entre sintomas depressivos e atividade nervosa simpática muscular (ANSM), medida por microneurografia. Houve também uma correlação positiva e significativa entre sintomas ansiosos e ANSM. / INTRODUCTION: It is well established that depression is associated with cardiac events, sudden death, higher cardiovascular mortality and higher incidence of coronary artery disease (CAD). A number of biological mechanisms linking depression and CAD have been identified, including dysregulation of autonomic nervous system (ANS). Studies with heart rate variability and catecholamines measures have been perfomed in depressed patients. Microneurography is a direct and efficient method to measure sympathetic nerve traffic in humans. To our knowledge, there is no previous study with microneurography in depressed patients. METHODS: ANS functioning, during rest and mental stress, in depressed patients was compared to controls. Nineteen depressed patients and 15 controls (18 to 45 years old) were involved in the study. Subjects with medical conditions and/or use of medications that could interfere on ANS were not included. Psychiatric evaluation included the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I/P, Version 2.0) and the Montgomery and Asberg Depression Rating Scale (MADRS). Muscle sympathetic nervous activity (MSNA) was directly measured from the peroneal nerve using microneurography. Forearm blood flow (FBF) was measured by venous occlusion pletysmography. Blood pressure (BP) was monitored noninvasively by an automatic BP cuff, and heart rate (HR) was measured by electrocardiogram. Baseline register was performed by 3 minutes and Stroop color word test was performed for 4 minutes. RESULTS: There was no difference in age, weight and body mass index between the two groups studied. No significant difference was found between groups in regard to systolic BP (SBP), diastolic BP (DBP), mean BP (MBP), HR, MSNA, FBF and forearm vascular conductance at baseline. All parameters significantly increased during mental stress in the two groups. The reactivity to mental stress showed no difference between groups. There was a significant positive correlation between MADRS total scores and mean baseline MSNA (0,84; p=0,0001) among depressed patients. There was also a significant positive correlation between MADRS tension scores and mean baseline MSNA (0,70; p=0,01) among depressed patients. CONCLUSIONS: There were no differences in baseline measures of sympathetic activity between depressed patients and controls. The reactivity to mental stress between the groups did not differ as well. There was a positive significant correlation between depressive symptoms and mean baseline MSNA. There was a positive significant correlation between anxiety symptoms and mean baseline MSNA.

Attempts were made to determine the pore properties, such as permeability, rectification and voltage-dependent block, of the putative TRPV4-TRPC1 channel. We demonstrated that this putative TRPV4-TRPC1 heterotetrameric channels displays distinct property different (although not drastically different) from TRPV4 homotetrameric channel with regard to I-V relation, kinetics of cation current, cations permeability and rectification properties. Together, the data from FRET and functional studies both suggest that heterologous expression of TRPV4 and TRPC1 can produce functional TRPV4-TRPC1 heterotetrameric channel. / Hemodynamic blood flow is one of most important physiological factors that control vascular tone. Flow shear stress acts on the endothelium to stimulate the release of vasodilators such as nitric oxide (NO), prostacyclin and endothelium-derived hyperpolarizing factors, causing endothelium-dependent vascular relaxation. In many cases, a key early signal in this flow-induced vascular dilation is Ca2+ influx in endothelial cells in response to flow. There is intense interest in searching for the molecular identity of the channels that mediate flow-induced Ca2+ influx. The present study aimed at identifying an interaction of TRPV4 with TRPC1, and investigating functional role of such a complex in flow-induced Ca2+ influx / In functional study, flow elicited a [Ca2+]i rise in TRPV4-expressing HEK cells. Co-expression of TRPC1 with TRPV4 markedly prolonged this [Ca2+]i transient, and it also enabled this [Ca2+]i transient to be negatively modulated by protein kinase G (PKG). Furthermore, this [Ca2+]i rise was inhibited by an anti-TRPC1 blocking antibody T1E3 and a dominant negative construct TRPC1Delta567-793. Physical interaction of TRPV4 with TRPC1 and functional role of such a complex were also found in the primary cultured rat mesenteric artery endothelial cells (MAECs) and human umbilical vein endothelial cells (HUVECs). A TRPC 1-specific siRNA was used to knock-down TRPC1 protein levels in HUVECs. Interestingly, this siRNA not only reduced the magnitude of flow-induced [Ca2+]i rise, but also accelerated the decay of flow-induced [Ca2+]i transient. Pressure myograph was used to investigate the functional role of such a complex in flow-induced vascular dilation. T1E3 also decreased flow-induced vascular dilation. Thogether, the data from endothelial cells are consistent with those in overexpressed HEK cells, supporting the notion that TRPC 1 interacts with TRPV4 to prolong the flow-induced[Ca2+]i transient, and that TRPV4-TRPC1 complex plays an important role in flow-induced vascular dilation. / In summary, my study demonstrated that TRPV4 is capable of assembling with TRPC1 to form a functional TRPV4-TRPC1 heteromeric channel. TRPV4-TRPC1 heteromeric channel can rapidly translocate to the plasma membrane after Ca 2+ depletion in intracellular stores. This TRPV4-TRPC1 heteromeric channel plays an important role in flow-induced endothelial Ca2+ influx and its associated vascular relaxation. / Ion channels are delivered to the plasma membrane via vesicle trafficking. Thus the vesicle trafficking is a key mechanism to control the amount of TRP channel proteins in the plasma membrane, where they perform their function. TRP channels in vivo are often composed of heteromeric subunits. However, up to the present, there is lack of knowledge on trafficking of heteromeric TRP channels via vesicular translocation. In the present study, we examined the effect of Ca2+ store depletion on the translocation of TRPV4-TRPC1 heteromeric channels to the plasma membrane. Experiments using total internal fluorescence reflection microscopy (TIRFM) and biotin surface labeling showed that depletion of intracellular Ca2+ stores triggered a rapid translocation of TRPV4-TRPC1 channel proteins into the plasma membrane. Fluorescent Ca2+ measurement and patch clamp studies demonstrated that store Ca2+ depletion augmented several TRPV4-TRPC1 complex-related functions, which include store-operated Ca2+ influx and cation current as well as 4alpha-PDD-stimulated Ca2+ influx and cation current. The translocation required stromal interacting molecule 1 (STIM1). Furthermore, TRPV4-TRPC1 complex is more favorably translocated to the plasma membrane than TRPC1 or TRPV4 homomers. Similar mechanisms were identified in native endothelial cells, where the TRPV4-TRPC I complex is a key component mediating flow-induced Ca2+ influx and subsequent vascular relaxation. / With the use of fluorescence resonance energy transfer (FRET), co-immunoprecipitation and subcellular colocalization methods, it was found that TRPC1 interacts physically with TRPV4 to form a heteromeric channel complex. In addition, our experimental results indicate that C-terminal and N-terminal domains of both channels are required for their interaction. / Ma, Xin. / Adviser: Yao Xiaodiang. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 109-121). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

O objetivo é comparar o fluxo sanguíneo total (FS) e a reserva de fluxo coronariano (RFC) aos ramos revascularizados pelas artérias torácica interna esquerda (ATIE) e radial (AR) nos enxertos compostos com os enxertos isolados. Foi realizado um ensaio clínico randomizado de 42 pacientes que foram distribuídos em grupo A ou ATIE e AR composta em Y(n=14), grupo B ou ATIE e AR composta modificada(n=14) e grupo C ou ATIE pediculada para DA e AR aorto-coronariana(n=14). Os pacientes foram submetidos a fluxometria no pós-operatório imediato. A RFC foi de 2,1 ± 0,44, 1,96 ± 0,3 e 2,06±0,42 nos grupos A,B e C, (p=0.7208 A, B x C) e o FS, em ml/min, foi 110±30, 145±59 e 136±58, respectivamente (p=0.3232 A,B x C). Concluindo, não houve diferença significativa do FS total e nem da RFC nos grupos estudados / The objective is to compare the total blood flow (Bf) and coronary flow reserve (CFR) to the left coronary branches that were revascularized with left internal thoracic (LITA) and radial artery (RA) in composite and independent arterial grafts. A randomized trial was realized and 42 patients assigned in group A or composite LITA-RA in a Y configuration (n=14), group B or modified composite LITA-RA(n=14) and group C or pedicled LITA to LAD and aorto-coronary RA (n=14). Patients were submitted to postoperative Bf velocity analysis. CFR was 2,1 ± 0,44, 1,96 ± 0,3 e 2,06±0,42 in groups A,B and C (p=0.7208 A, B x C) and Bf, in ml/min, was 110±30, 145±59 and 136±58, respectively (p=0.3232 A, B x C). In conclusion there was no difference in Bf and CFR in the groups studied

The ultimate goal of this research is to develop the capability of direct numerical simulation of a flow containing numerous rigid finite size particles. In order to reach this goal, we have implemented the smoothed profile method (SPM) in the University of Iowa in-house solver, pELAFINT3D and overcame several challenges related to the method. This includes a proposed formulation for the interface thickness and many validations and comparisons with experimental data as well as with a second-order accurate sharp interface method. As one of the issues related to low-density particles is the instability, SPM has been improved by developing to a fully implicit scheme. Moreover, use of higher order integration formulation and implementation of Euler parameters have been shown to be helpful in stabilization of the calculations. To preserve the efficiency when the number of the particles increases, local mesh refinement is shown to be a very effective tool. A revised version of SPM that has only one projection step is proposed to improve the efficiency of the method. A comprehensive efficiency study is performed and it has been shown that the new method is less expensive in problems with high added mass effect when strongly coupled fluid-structure interaction schemes are used. Moreover, the code is massively parallelized using MPI and PETSc libraries. The parallelization includes I/O, operations leading to construction of the linear solver as well as the solver itself. Simulation of a particle laden flow involves particles collisions. Two novel collision models are suggested which are able to avoid particle overlapping for arbitrary shape particles. The methods are efficient as they are not involved with extra grid refinement related to implementing lubrication forces. The issue of handling continuously changing number of particles in a particle laden flow is solved by implementation of a linked list data structure for the particles. By studying a flow over a constricted region we showed that the platelets’ activation is more likely to happen for the particles that pass from the middle of the upper bump region because those particles will have longer exposure time to the high shear flow behind the bump. PDF contour of particles’ presence show the more concentrated presence of the particles near the bump. Moreover, the interaction of RBCs and platelets pushes the platelets toward the wall after the bottom wall.