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Thesis (Ph. D.) -- University of Texas Southwestern Medical Center at Dallas, 2004. / Vita. Bibliography: References located at the end of each chapter.

Orientadores: Jose Wilson Magalhães Bassani, Rosana Almada Bassani / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-10T21:37:34Z (GMT). No. of bitstreams: 1 Oliveira_PedroXavierde_D.pdf: 1201901 bytes, checksum: 1bcd2243dc00b131571c89796a38a8f8 (MD5) Previous issue date: 2008 / Resumo: A desfibrilação é a única terapia conhecida para reverter o quadro de fibrilação ventricular. Entretanto, a estimulação do coração com campos elétricos de grande magnitude durante a desfibrilação pode lesar miócitos cardíacos, e, como conseqüência, a eficiência contrátil do coração ser reduzida. Neste trabalho, estudamos o efeito da estimulação por campo elétrico (E) de alta intensidade sobre miócitos cardíacos isolados de rato. O valor máximo de potencial extracelular gerado por E (Ve-max) foi estimado usando-se um modelo eletromagnético. Os principais resultados foram: a) A aplicação de E de alta intensidade causa aumento sustentado de [Ca2+] citoplasmática ([Ca2+ ]i), bem como contratura, que são dependentes de [Ca2+] extracelular; para campos maiores que 50 V/cm, estas respostas são irreversíveis e levam à morte celular; b) retículo sarcoplásmatico, mitocôndrias, trocador Na+-Ca2+ de canais de Ca2+ do sarcolema não contribuem de forma significativa para estes efeitos; c) durante aplicação de choques a células despolarizadas com alta [K+] extracelular, observou-se um incremento de Ve-max semelhante ao valor do potencial transmembrana de repouso (Vm ~-85 mV), o que indica que Ve-max pode ser considerado uma estimativa razoável da máxima variação de Vm durante o choque; d) aumento da resistência celular ao efeito letal de E, avaliada pelo valor de E associado a probabilidade de letalidade de 50% (EL50), ocorreu com a aplicação de pulsos bipolares da mesma energia, durante a estimulação de receptores ß- adrenérgicos, e em miócitos isolados de animais nos quais foi induzido stress por imobilização e choques nas patas repetidos. Conclui-se que: a) O aumento sustentado de [Ca2+]i ocorre provavelmente por influxo do íon através de poros hidrofílicos formados na membrana devido à imposição de E de alta intensidade (eletroporação); b) a superioridade de pulsos desfibrilatórios bipolares, já descrita na literatura, pode dever-se, pelo menos em parte, pelo menor potencial letal desta forma de onda; c) tanto a estimulação ß-adrenérgica in vitro, quanto a condição de stress parecem conferir proteção contra o efeito letal de E. Espera-se que estes resultados representem uma contribuição para o desenvolvimento de procedimentos mais seguros, tanto para desfibrilação, quanto para estimulação marca-passo do coração / Abstract: Electric defibrillation is currently the treatment able to reverse ventricular fibrillation. However, cardiac stimulation with high-intensity electric fields may cause injury to myocardial cells, thus impairing cardiac contractility. In this study, the effects of highintensity electric fields (E) on isolated rat ventricular myocytes were analyzed. The maximum value of field-induced extracellular potential (Ve-max) was estimated using an electromagnetic model. Our main results were: a) Application of high-intensity E causes sustained increase in cytosolic [Ca2+] ([Ca2+]i) and marked cell contracture, and both effects depend on the presence of extracellular Ca2+; for E> 50 V/cm, these responses are irreversible and lethal injury develops; b) sarcoplasmic reticulum, mitochondria, Na+-Ca2+ exchanger and sarcolemmal L-type Ca2+ channels do not seem to contribute significantly to such effects; c) when shocks were applied to cells depolarized by high extracellular [K+], Ve-max was increased by an extent that was close to the value of the resting transmembrane potential (Vm ~-85 mV), which indicates that Ve-max may be considered a reasonable estimation of the maximum variation of Vm during the shock; d) increase in cell resistance to the lethal effect of E, assessed as the value of E associated to 50% probability of lethality (EL50), was observed during application of biphasic stimuli with the same pulse energy, during ß-adrenergic receptor stimulation, and in myocytes isolated from rats in which stress was induced by repeated immobilization and footshock. It may be concluded that: a) The sustained increase in [Ca2+]i is probably due to Ca2+ influx through hydrophilic membrane pores generated during application of high-intensity E (electroporation); b) the better defibrillation results described in the literature with biphasic shock may be due, at least partly, to the lesser ability of this waveform to cause lethal injury; c) both in vitro ß-adrenergic stimulation and the stress condition in vivo appear to exert a protective effect against the lethal effect of E. We expect that the present results may contribute to the development of safer procedures for both pacemaker and defibrillatory field stimulation of the myocardium / Doutorado / Engenharia Biomedica / Doutor em Engenharia Elétrica

Introdução: A hipertrofia ventricular esquerda é importante fator de risco de morbidade e mortalidade cardiovascular. Sua associação com variantes funcionais do sistema renina-angiotensina é controversa. Objetivos: Avaliar a associação entre massa ventricular esquerda e função sistólica e diastólica do ventrículo esquerdo e os polimorfismos inserção/deleção do gene da enzima de conversão da angiotensina e M235T do gene do angiotensinogênio. Métodos: Estudo observacional realizado numa amostra da população da cidade de Vitória (Espírito Santo), utilizando como base a metodologia do projeto Mônica da Organização Mundial da Saúde. Realizamos avaliação clínica, perfil antropométrico, análise laboratorial e ecocardiograma em 652 indivíduos previamente genotipados para polimorfismos da enzima de conversão da angiotensina e do angiotensinogênio. Analisamos massa ventricular esquerda indexada pela área de superfície corpórea e pela altura2,13. Classificamos o ventrículo esquerdo em padrões geométricos: padrão normal, remodelamento concêntrico, hipertrofia concêntrica e hipertrofia excêntrica. A função sistólica ventricular esquerda foi avaliada pela fração de ejeção medida ao modo unidimensional. A função diastólica foi analisada pelo fluxo mitral (onda E, onda A, relação E/A, tempo de desaceleração e tempo de relaxamento isovolumétrico) e pelo Doppler tecidual (velocidade miocárdica em região próxima ao anel mitral septal e lateral: ondas E e A e relação E/E). Resultados: A média de idade da população estudada foi 51 ± 10 anos sendo 59% dos participantes do sexo feminino e 20,8% obesos. Em nossa amostra, 47% dos indivíduos foram classificados como hipertensos. Não houve associação entre hipertensão arterial e os genótipos analisados. Após análise univariada, não encontramos associação entre os polimorfismos inserção/deleção da enzima de conversão da angiotensina e M235T do angiotensinogênio e índice de massa ventricular esquerda, padrões geométricos do ventrículo esquerdo, função sistólica avaliada pela fração de ejeção e os vários parâmetros de função diastólica analisados. / Introduction: Left ventricular hypertrophy is an important risk factor for cardiovascular morbidity and mortality. Its association with the reninangiotensin system genetic variants is controversial. Objectives: To assess the association between left ventricular mass, left ventricle systolic and diastolic functions, and polymorphisms of the insertion/deletion angiotensin converting enzyme and M235T angiotensinogen genes. Methods: Observational study in adults from Vitoria (Brazil) using the methodology of the Monica project of the World Health Organization. We performed clinical examination, anthropometric assessment, laboratory analysis and transthoracic echocargiography studies in 652 adults who were previously genotyped for polymorphisms of the angiotensin-converting enzyme and angiotensinogen. We measured left ventricular mass indexed to body surface area and height 2,13, left ventricular ejection fraction, and diastolic function using mitral flow and tissue Doppler. Left ventricle was classified into following geometric patterns: normal, concentric remodeling, concentric hypertrophy and eccentric hypertrophy. Left ventricular systolic function was assessed by ejection fraction by analysis of the M-mode echocardiogram. Diastolic function was assessed using mitral flow (E wave, A wave, E/A ratio, deceleration time and isovolumic relaxation time), and Doppler tissue imaging (mitral annulus velocity in septal and lateral region: E` and A` waves, and E/E`ratio). Results: Mean age of the studied population was 51±10 years; 59% of the subjects were women and 20,8% were obese. Forty seven percent of the individuals were classified as hypertensive. Hypertension was not associated with any of the studied genotypes. Univarate analysis showed no correlation between polymorphisms of the insertion/deletion angiotensin-converting enzyme and M235T angiotensinogen gene variants, left ventricular mass index, left ventricular geometric patterns, and systolic and diastolic functions. Taking together these data indicated no evidence for the association of ACE and angiotensinogen gene variants with cardiac mass and function assessed by echocardiography.

INTRODUÇÃO: O objetivo desta pesquisa foi medir, através da endoscopia, o plexo corióideo no forame interventricular e estruturas no assoalho do terceiro ventrículo, bem como a distância entre as artérias comunicantes posteriores e comparar essas variáveis. MÉTODOS: Estudo observacional, prospectivo realizado em 37 cérebros de cadáveres humanos adultos, de ambos os sexos, no Serviço de Verificação de Óbitos da Universidade de São Paulo, em abril de 2008, utilizando neuroendoscópio rígido. As imagens endoscópicas foram gravadas, corrigidas para distorção e mensuradas. A medida macroscópica entre as artérias comunicantes posteriores foi realizada após o estudo endoscópico. RESULTADOS: As medidas do plexo corióideo no forame interventricular, a distância látero-lateral dos corpos mamilares, a distância do recesso do infundíbulo até os corpos mamilares e do triângulo de segurança no túber cinéreo foram 1,71 mm (±0,77 mm), 2,23 mm (±0,74 mm), 3,22 mm (±0,82 mm), 3,69 mm2 (±2,09 mm2), respectivamente. O aspecto do assoalho do terceiro ventrículo e a distância interna dos corpos mamilares foi 84% opaco e 89% ausente, respectivamente. A distância média entre as artérias comunicantes posteriores foi de 12,5 mm (±2,3 mm). Associações entre translucidez do assoalho do terceiro ventrículo com as seguintes variáveis: distância láterolateral e distância interna dos corpos mamilares, assim como idade, foram identificadas. CONCLUSÕES: Até esta pesquisa, não existiam medidas sobre o plexo corióideo no forame interventricular e distância entre as artérias comunicantes posteriores na região dos corpos mamilares. As variáveis restantes, quando comparadas com a literatura, foram em maior número e em cérebros normais / INTRODUCTION: the objective of this research was to measure, through endoscopy, the interventricular foramen choroid plexus and the third ventricle floor structures, as well the distance between the communicating posterior arteries and compare these variables. METHODS: an observational, prospective study was conducted in 37 brains of adult human cadavers, of both sexes at the Death Check Unit of the University of São Paulo, in April 2008 by means of the rigid neuroendoscope. The endoscopic images were recorded, corrected for distortion and measured. The macroscopic measure between the communicating posterior arteries was performed after the endoscopic study. RESULTS: The measures of the interventricular foramen choroid plexus, the latero-lateral distance of mammillary bodies, the distance from the infundibular recess to the mammillary bodies, safety triangle in the tuber cinereum were 1.71 mm (±0.77 mm), 2.23 mm (±0.74 mm), 3.22 mm (±0.82 mm), 3.69 mm2 (±2.09 mm2), respectively. The aspect of the third ventricle floor and the internal distance of the mammillary bodies was 84% opaque and 89% absent, respectively. The mean distance between the communicating posterior arteries was 12.5 mm (±2.3 mm). Associations between the translucent floor of the third ventricle with the following variables: latero-lateral distance and internal distance of the mammillary bodies, as well as age were identified. CONCLUSIONS: Up this research, there was no account on the measures of the interventricular foramen choroid plexus and the distance between communicating posterior arteries at the level of the mammillary bodies. The remaining variables were in greater number and in normal brains, as compared with the literature

Submitted in fulfillment of the requirements for the Degree of Masters in Technology: Cardiology, Durban University of Technology, 2012. / Cardiomyopathies and their resultant heart failure (HF) remain a major cause of cardiovascular morbidity and mortality (Wood and Picard, 2004). Idiopathic dilated cardiomyopathy (IDCMO) is a primary myocardial disease of unknown cause, characterized by left ventricular (LV) or biventricular dilatation and impaired myocardial contractility. Dilated cardiomyopathy (DCMO), along with rheumatic heart disease and hypertension (HPT), is one of the leading causes of HF in Africa. In fact, in an epidemiology study of 884 patients in Soweto, IDCMO was the second major cause of HF. Thirty five percent of patients in the study, with HF, had IDCMO (Sliwa, Damasceno, Mayosi, 2005). Methodology: Patients referred to the cardiomyopathy (CMO) clinic at Chris Hani Baragwanath hospital, situated in the echocardiographic lab, were recruited, provided they satisfied the exclusion and inclusion criteria and were enrolled after obtaining voluntary informed consent. From May 2009 to September 2010, 70 patients with IDCMO were recruited for this trial. Patients with DCMO were identified by means of echocardiographic criteria which included a left ventricular ejection fraction (LVEF) of less than 45% and an end diastolic dimension (EDD) of greater than of 52 mm (2D in long parasternal axis). Results: In the present study the prevalence of left ventricular (LV) thrombus in patients with IDCMO was 18.6%. When using Univariate logistic regression, the only independent predictors of LV thrombus formation was LVEF and age. However, when multivariate logistic regression analysis was applied to the data, the only predictor with a significant association was age. The reason for this is not clear. It is postulated that perhaps younger patients have differences in the pathophysiology of their disease such as a greater smoldering inflammatory component which may therefore predispose them to thrombus formation. For example the presence of IL-6 may be important in the formation of LV clot in cases of LV dysfunction (Sosin, Bhatia, Davis, Lip, 2003). The association between LVEF and LV thrombus was borderline significant. Conclusion: The prevalence of LV thrombus formation in this cohort of patients with IDCMO was 18.6%. Echocardiographic parameters alone cannot predict which patients are more likely to develop thrombus formation. / National Research Foundation / M

Abstract Collagen XIII is a type II transmembrane protein, which has a short intracellular domain and a large, mainly collagenous ectodomain. It is located at many cell-matrix junctions and in focal adhesions in cultured cells and it has a function in cell adhesive processes. Overexpression of collagen XIII molecules with an 83 amino acid deletion in part of the ectodomain leads to fetal lethality in Col13a1del transgenic mice. Doppler ultrasonography was performed at 12.5 days of gestation on fetuses resulting from heterozygous matings and matings between heterozygous and wild-type mice. Some fetuses had atrioventricular valve regurgitation (AVVR) and all of them were transgene positive. In addition, fetuses had pathological changes in functional parameters. Histological analysis showed the trabeculation of the ventricles to be reduced and the myocardium to be thinner in the fetuses with AVVR. Based on in situ hybridization (ISH), collagen XIII mRNA are normal constituents of these structures. Overexpression of mutant collagen XIII results in mid-gestation cardiac dysfunction in fetuses, and these disturbances in cardiac function may lead to death in utero. The heterozygous mice that were initially of normal appearance had an increased susceptibility to develop B cell lymphomas, which originated in the mesenteric lymph node. Collagen XIII protein was not detected in normal lymph nodes or in the lymphomas. The incidence of lymphomas was higher in conventional conditions than in a specific pathogen-free facility. In addition, the expression of collagen XIII was localized in the intestine and the basement membrane was highly abnormal. These findings suggest that collagen XIII is a critical determinant of lymphanogenesis. Using ISH, antibody staining and RT-PCR techniques collagen XIII expression was analyzed during carcinogenesis in mice and in man. Collagen XIII expression increased during carcinogenesis in mice and in man. In the malignant process collagen XIII mRNA localized in the basal epithelium and in the invasive cells. According to antibody staining malignant invasive cells were positive. Results may reflect the disturbed adhesion of epithelial cells and ECM and that may affect the behaviour of the malignant cells, suggesting that collagen XIII has a significant role in the initiation of the invasion.

Cardiovascular diseases account for the majority of deaths both worldwide and in the Czech Republic. Main factors contributing heart disease development, aside age and sex, are obesity, high blood pressure and high blood cholesterol and triglyceride levels. Spontaneously hypertensive rat (SHR) was developed and used for search of genetic determinants of these traits. This commonly used rat model develops hypertension, dyslipidemia, and insulin resistance naturally which is caused by aberrant Cd36 fatty acid translocase gene. Previous studies have shown that rescue of Cd36 performed in the transgenic SHR-Tg19 strain enhances cardiac beta-adrenergic system, slightly increases heart mass and leads to higher susceptibility to arrhythmias. The present thesis had two main aims: 1) To investigate whether and how a transgenic rescue of Cd36 in SHR affects protein composition, mitochondrial function and activity of selected metabolic enzymes of the heart. 2) To study the expression and distribution of selected components of beta-adrenergic signaling system in lipid raft isolated form membranes using the TX-100 detergent. We set to compare two commonly used proteomic approaches, 2D electrophoresis with MALDI-TOF mass spectrometry and label-free LC-MS. The results did not reveal any overlap between...

Tesis por compendio / [EN] Heart failure (HF) constitutes a major public health problem worldwide. Operationally it is defined as a clinical syndrome characterized by the marked and progressive inability of the ventricles to fill and generate adequate cardiac output to meet the demands of cellular metabolism that may have significant variability in its etiology and it is the final common pathway of various cardiac pathologies. Much attention has been paid to the understanding of the arrhythmogenic mechanisms induced by the structural, electrical, and metabolic remodeling of the failing heart. Due to the complexity of the electrophysiological changes that may occur during heart failure, the scientific literature is complex and sometimes equivocal. Nevertheless, a number of common features of failing hearts have been documented. At the cellular level, prolongation of the action potential (AP) involving ion channel remodeling and alterations in calcium handling have been established as the hallmark characteristics of myocytes isolated from failing hearts. At the tissue level, intercellular uncoupling and fibrosis are identified as major arrhythmogenic factors. In this Thesis a computational model for cellular heart failure was proposed using a modified version of Grandi et al. model for human ventricular action potential that incorporates the formulation of the late sodium current (INaL) in order to study the arrhythmogenic processes due to failing phenotype. Experimental data from several sources were used to validate the model. Due to extensive literature in the subject a sensitivity analysis was performed to assess the influence of main ionic currents and parameters upon most related biomarkers. In addition, multiscale simulations were carried out to characterize this pathology (transmural cardiac fibres and tissues). The proposed model for the human INaL and the electrophysiological remodeling of myocytes from failing hearts accurately reproduce experimental observations. An enhanced INaL appears to be an important contributor to the electrophysiological phenotype and to the dysregulation of calcium homeostasis of failing myocytes. Our strand simulation results illustrate how the presence of M cells and heterogeneous electrophysiological remodeling in the human failing ventricle modulate the dispersion of action potential duration (APD) and repolarization time (RT). Conduction velocity (CV) and the safety factor for conduction (SF) were also reduced by the progressive structural remodeling during heart failure. In our transmural ventricular tissue simulations, no reentry was observed in normal conditions or in the presence of HF ionic remodeling. However, defined amount of fibrosis and/or cellular uncoupling were sufficient to elicit reentrant activity. Under conditions where reentry was generated, HF electrophysiological remodeling did not alter the width of the vulnerable window (VW). However, intermediate fibrosis and cellular uncoupling significantly widened the VW. In conclusion, enhanced fibrosis in failing hearts, as well as reduced intercellular coupling, combine to increase electrophysiological gradients and reduce electrical propagation. In that sense, structural remodeling is a key factor in the genesis of vulnerability to reentry, mainly at intermediates levels of fibrosis and intercellular uncoupling. / [ES] La insuficiencia cardíaca (IC) constituye un importante problema de salud pública en todo el mundo. Operacionalmente se define como un síndrome clínico caracterizado por la incapacidad marcada y progresiva de los ventrículos para llenar y generar gasto cardíaco adecuado para satisfacer las demandas del metabolismo celular, que puede tener una variabilidad significativa en su etiología y es la vía final común de varias patologías cardíacas. Se ha prestado mucha atención a la comprensión de los mecanismos arritmogénicos inducidos por la remodelación estructural, eléctrica, y metabólica del corazón afectado de IC. Debido a la complejidad de los cambios electrofisiológicos que pueden ocurrir durante la IC, la literatura científica es compleja y, a veces equívoca. Sin embargo, se han documentado una serie de características comunes en corazones afectados de IC. A nivel celular, se han establecido como las características distintivas de los miocitos aislados de corazones afectados de IC la prolongación del potencial de acción (PA), que implica la remodelación de los canales iónicos y las alteraciones en la dinámica del calcio. A nivel de los tejidos, el desacoplamiento intercelular y la fibrosis se identifican como los principales factores arritmogénicos. En esta tesis se propuso un modelo celular computacional para la insuficiencia cardíaca utilizando una versión modificada del modelo de potencial de acción ventricular humano de Grandi y colaboradores que incorpora la formulación de la corriente tardía de sodio (INaL) con el fin de estudiar los procesos arritmogénicas debido al fenotipo de la IC. Los datos experimentales de varias fuentes se utilizaron para validar el modelo. Debido a la extensa literatura en la temática se realizó un análisis de sensibilidad para evaluar la influencia de las principales corrientes iónicas y los parámetros sobre los biomarcadores relacionados. Además, se llevaron a cabo simulaciones multiescala para caracterizar esta patología (en fibras y tejidos transmurales). El modelo propuesto para la corriente tardía de sodio y la remodelación electrofisiológica de los miocitos de corazones afectados de IC reprodujeron con precisión las observaciones experimentales. Una INaL incrementada parece ser un importante contribuyente al fenotipo electrofisiológico y la desregulación de la homeostasis del calcio de los miocitos afectados de IC. Nuestros resultados de la simulaciones en fibra ilustran cómo la presencia de células M y el remodelado electrofisiológico heterogéneo en el ventrículo humano afectado de IC modulan la dispersión de la duración potencial de acción (DPA) y el tiempo de repolarización (TR). La velocidad de conducción (VC) y el factor de seguridad para la conducción (FS) también se redujeron en la remodelación estructural progresiva durante la insuficiencia cardíaca. En nuestras simulaciones transmurales de tejido ventricular, no se observó reentrada en condiciones normales o en presencia de la remodelación iónica de la IC. Sin embargo, determinadas cantidades de fibrosis y / o desacoplamiento celular eran suficientes para provocar la actividad reentrante. En condiciones donde se había generado la reentrada, el remodelado electrofisiológico de la IC no alteró la anchura de la ventana vulnerable (VV). Sin embargo, niveles intermedios de fibrosis y el desacoplamiento celular ampliaron significativamente la VV. En conclusión, niveles elevados de fibrosis en corazones afectados de IC, así como la reducción de acoplamiento intercelular, se combinan para aumentar los gradientes electrofisiológicos y reducir la propagación eléctrica. En ese sentido, la remodelación estructural es un factor clave en la génesis de la vulnerabilidad a las reentradas, principalmente en niveles intermedios de fibrosis y desacoplamiento intercelular. El remodelado electrofisiológico promueve la arritmogénesis y puede ser alterado dependi / [CA] La insuficiència cardíaca (IC) constitueix un important problema de salut pública arreu del món. A efectes pràctics, es defineix com una síndrome clínica caracteritzada per la incapacitat marcada i progressiva dels ventricles per omplir i generar el cabal cardíac adequat, per tal de satisfer les demandes del metabolisme cel·lular, el qual pot tenir una variabilitat significativa en la seua etiologia i és la via final comuna de diverses patologies cardíaques. S'ha prestat molta atenció a la comprensió dels mecanismes aritmogènics induïts per la remodelació estructural, elèctrica, i metabòlica del cor afectat d'IC. A causa de la complexitat dels canvis electrofisiològics que poden ocórrer durant la IC, trobem que la literatura científica és complexa i, de vegades, equívoca. No obstant això, s'han documentat una sèrie de característiques comunes en cors afectats d'IC. A nivell cel·lular, com característiques distintives dels miòcits aïllats de cors afectats d'IC, s'han establert la prolongació del potencial d'acció (PA), que implica la remodelació dels canals iònics, i les alteracions en la dinàmica del calci. A nivell dels teixits, el desacoblament intercel·lular i la fibrosi s'identifiquen com els principals factors aritmogènics. Per tal d'estudiar els processos aritmogènics a causa del fenotip de la IC, es va proposar un model cel·lular computacional d'IC utilitzant una versió modificada del model de potencial d'acció ventricular humà de Grandi i els seus col·laboradors, el qual incorpora la formulació del corrent de sodi tardà (INaL). Amb l'objectiu de validar el model es van utilitzar dades experimentals de diverses fonts. A causa de l'extensa literatura en la temàtica, es va realitzar una anàlisi de sensibilitat per tal d'avaluar la influència de les principals corrents iòniques i els paràmetres sobre els biomarcadors relacionats. A més, es van dur a terme simulacions multiescala per a la caracterització d'aquesta patología (fibres i teixits transmurals). El model proposat per al corrent de sodi tardà i la remodelació electrofisiològica dels miòcits de cors afectats d'IC van reproduir amb precisió les observacions experimentals. Una INaL incrementada sembla contribuir de manera important al fenotip electrofisiològic i a la desregulació de l'homeòstasi del calci dels miòcits afectats d'IC. Els resultats de les nostres simulacions en fibra indiquen que la presència de cèl·lules M i el remodelat electrofisiològic heterogeni en el ventricle humà afectat d'IC modulen la dispersió de la durada del potencial d'acció (DPA) i el temps de repolarització (TR). La velocitat de conducció (VC) i el factor de seguretat per a la conducció (FS) també es van reduir en la remodelació estructural progressiva durant la IC. A les nostres simulacions transmurals de teixit ventricular, no s'observà cap reentrada ni en condicions normals ni en presència de la remodelació iònica de la IC. No obstant això, amb determinades quantitats de fibrosi i/o desacoblament cel·lular sí que es provocà l'activitat reentrant. I amb les condicions que produïren la reentrada, el remodelat electrofisiològic de la IC no va alterar l'amplada de la finestra vulnerable (FV). Tanmateix, nivells intermedis de fibrosi i el desacoblament cel·lular sí que ampliaren significativament la FV. En conclusió, nivells elevats de fibrosi en cors afectats d'IC, així com la reducció d'acoblament intercel·lular, es combinen per augmentar els gradients electrofisiològics i reduir la propagació elèctrica. Per tant, la remodelació estructural és un factor clau en la gènesi de la vulnerabilitat a les reentrades, principalment en nivells intermedis de fibrosi i desacoblament intercel·lular. / Gómez García, JF. (2015). Multiscale Modeling and Simulation of Human Heart Failure [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/52389 / Compendio

O objetivo deste estudo foi relacionar a gravidade da ventriculomegalia cerebral fetal isolada com o desenvolvimento neurológico pós-natal. Um total de 36 fetos com diagnóstico ultra-sonográfico de ventriculomegalia cerebral isolada foram acompanhados e avaliados quanto ao seu desenvolvimento neurológico entre 0 e 26 meses. Foi definido como ventriculomegalia leve a medida do átrio entre 10 a 15 mm e grave, maior que 15 mm Nos casos de ventriculomegalia grave (n = 19) tivemos 6 óbitos e 3 alterações neurológicas graves. No grupo de ventriculomegalia leve (n = 16) observou-se 3 alterações neurológicas leves / The objective of this study was to correlate the severity of the isolated fetal cerebral ventriculomegaly with the postnatal neurological development. Thirty-six fetuses with ultrasonographic cerebral ventriculomelagy diagnostic were attended and neurological development at the 0 to 26 life months. The definition of according to the ventricular atrium measurements: mild 10 to 15 mm and severe over 15 mm ventriculolomegaly. There cases severe ventriculomegaly (n = 19) the postnatal mortality.6 and 3 neurological development severe. The group with mild ventriculomegaly (n = 16) the neurological development evaluation 3 was light alterations