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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
291

Heterogeneidade e mecanismos moleculares da atividade anti-apoptótica das subfrações de HDL em células endoteliais humanas / Heterogeneity and molecular mechanisms of anti-apoptotic activity of high-density lipoprotein (HDL) subfractions on endothelial cells

Souza, Juliana Ascenção de 19 March 2007 (has links)
Introdução: A lipoproteína de baixa densidade (LDL) e suas formas oxidadas (LDLox) possuem múltiplas propriedades aterogênicas, atuando na deposição de colesterol, indução e manutenção da inflamação, disfunção endotelial, surgimento de células espumosas na parede arterial e conseqüente formação da placa de ateroma. Adicionalmente, LDLox induz apoptose de células endoteliais humanas (HMEC). A lipoproteína de alta densidade (HDL) possui inúmeras atividades antiaterogênicas, incluindo ações antioxidante, anti-inflamatória e anti-trombótica. A HDL é capaz de proteger as HMEC contra apoptose. As subfrações de HDL (sHDL) são heterogêneas em sua composição físico-química e atividades biológicas. A atividade antioxidante das sHDL aumenta com a densidade (HDL2b<HDL2a<HDL3a<HDL3b <HDL3c) e está deficiente em pacientes com SMet. Contudo, a heterogeneidade da atividade anti-apoptótica das sHDL é ainda desconhecida. Objetivos: (i) avaliar a heterogeneidade da atividade protetora das sHDL de indivíduos normolipidêmicos (n=7) e de pacientes com SMet (n=16) contra apoptose de HMEC induzida por LDLox; (ii) definir os mecanismos moleculares envolvidos nesta atividade. Métodos: Através de ultracentrifugação por gradiente de densidade, isolamos cinco diferentes sHDL. HMEC foram incubadas com LDLox (200 ?g apoB/ml) na presença ou não das sHDL (5-100 ?g proteína/ml). Os marcadores de toxicidade (MTT) e de apoptose celular (microscopia de fluorescência, marcagem com anexina V, cit c, AIF, degradação Bid, atividade caspase-3 e fragmentação do ADN) foram analisados. Resultados: Todas sHDL protegeram as HMEC contra a toxicidade e apoptose induzidas pela LDLox. Com mesma concentração de proteína, as subfrações HDL3c (60% proteção - MTT - e >100% - anexina V) e 3b (43% e 67%, respectivamente) de indivíduos normolipidêmicos apresentaram atividade anti-apoptótica mais potente do que as subfrações HDL2a (29% e 28%; p<0,01 vs. HDL3c, respectivamente) e 2b (25% e 62%; p<0,001 vs. HDL3c, respectivamente). Todas sHDL reduziram geração de espécies reativas de oxigênio (ROS) induzida pela LDLox, sendo a HDL3c (54%) mais potente do que HDL2b (21%; p<0.05 vs. HDL3c). Houve correlação positiva entre as atividades anti-apoptótica e antioxidante intracelular com conteúdo de apoA-I e esfingosina 1-fosfato (E1F) das sHDL, senda HDL3b e 3c ricas em E1F. A atividade anti-apoptótica da E1F e das sHDL parece depender da interação com as células endoteliais via apoA-I e seu receptor SR-BI. Finalmente, as HDL3c (n=5) isoladas de pacientes com SMet possuem conteúdo significativamente menor de apoA-I e reduzida atividade anti-apoptótica (60%, p<0,01), quando comparada aos controles normolipidêmicos (n=5). Houve tendência à diminuição da proteção contra a geração de ROS (SMet, n=10). Conclusão: As subfrações HDL3c protegem de forma potente as células endoteliais humanas contra toxicidade e apoptose induzidas pela LDLox, assim como contra geração de ROS. Esta atividade antiapoptótica está reduzida na SMet. / Background: Low density lipoprotein (LDL) and its oxidized forms (oxLDL) have several atherogenic properties, including cholesterol deposition, inflammation, endothelial dysfunction and foam cell formation on the arterial wall, leading to atherosclerotic plaque development. In addition, oxLDL induces human endothelial cell apoptosis (HMEC). High-density lipoprotein (HDL) has number of antiatherogenic activities, as antioxidative, anti-inflammatory and anti-thrombotic actions. HDL displays anti-apoptotic activity and is able to protect endothelial cells against oxLDL-induced apoptosis. HDL subfractions (sHDL) are highly heterogeneous in their physical and chemical composition and biological functions. Antioxidative activity of HDL subfractions increases with increment in density, HDL2b<HDL2a<HDL3a<HDL3b <HDL3c. Important, HDL subfractions from subjects with metabolic syndrome (MetS), display a significantly lower antioxidative activity as compared to healthy controls. However, the heterogeneity of their anti-apoptotic activity was not demonstrated. Objectives: (i) to evaluate the heterogeneity of antiapoptotic activity of sHDL from normolipidemic controls (n=7) and MetS patients (n=16) towards oxLDL-induced apoptosis of HMEC; (ii) to define molecular mechanisms involved in this anti-apoptotic action. Methods: Five major sHDL were fractionated by density gradient ultracentrifugation. HMEC were incubated with mildly oxLDL (200 ?g apoB/ml) in the presence or absence of each sHDL (5-100 ?g protein/ml). Markers of cellular toxicity (MTT) and apoptosis (fluorescent nucleic acid staining, annexin V binding, cytochrome c, AIF and Bid, caspase-3 activity and DNA fragmentation) were observed. Results: All HDL subfractions isolated from normolipidemic subjects protected HMEC against oxLDL-induced toxicity and apoptosis. At equal protein concentrations, HDL3c (60% protection in the MTT test; >100% in annexin V biding) and 3b subfractions (43% and 67%, respectively) were more potent against oxLDL-induced toxicity and apoptosis as compared to HDL2a (29% and 28%; p<0.01 vs. HDL3c, respectively) and 2b subfractions (25% and 62%; p<0.001 vs. HDL3c, respectively). All HDL subfractions attenuated of reactive oxygen species (ROS) generation in HMEC induced by oxLDL. Again, HDL3c (54% inhibition) were more potent as compared to HDL2b (21%; p<0.05 vs. HDL3c). The anti-apoptotic and intracellular antioxidative activities of HDL3 were positively correlated with apoA-I and sphingosine 1-phosphate (S1P) content of sHDL and, possibly, depend on their cellular interaction through apoA-I and its SR-BI receptor. The sHDL3c isolated from MetS patients (n=5) possess reduced content of apoA-I and less potent anti-apoptotic activity (-60%, p<0.01) than controls (n=5). Conclusion: Normolipidemic small dense HDL3 provide potent protection of human endothelial cells from oxLDL-induced apoptosis; this anti-apoptotic activity is reduced in the MetS.
292

Pharmacogenetics of rosuvastatin therapy and genetic determinants of some cardiovascular risk factors in Chinese patients. / CUHK electronic theses & dissertations collection

January 2010 (has links)
Although the clinical efficacy of statins has been well established, there is a wide inter-individual variation in the lipid responses to statins. Pharmacogenetic studies have identified some genetic differences that contribute to the variation, but overall the results have been disappointing. The studies described in this thesis were performed to examine whether certain genetic variants predicted the lipid responses to rosuvastatin in Chinese patients. Over 400 Chinese patients with increased risk of cardiovascular disease (CVD) who were treated with rosuvastatin 10 mg daily for at least 4 weeks (more than 97% of patients had at least 6 weeks treatment) were studied, including 166 having familial hypercholesterolaemia (FH) and 36 having rheumatoid arthritis (RA). They were genotyped for 135 polymorphisms in 62 candidate genes/loci potentially related to pharmacokinetics or pharmacodynamics of statins and lipid metabolism. Associations between genetic polymorphisms and the lipid responses to rosuvastatin were analyzed in 386 patients with good compliance. The associations between genetic polymorphisms and some risk factors for CVD including baseline lipid levels, high-sensitivity C-reactive protein (hsCRP), uric acid and bilirubin levels were also analyzed. / Some novel genetic determinants of the LDL-C response to rosuvastatin treatment have been identified in this study. The responses in HDL-C and triglycerides were related more closely to the baseline levels of these lipids than to any of the polymorphisms examined. Genetic associations with baseline lipid parameters, hsCRP, uric acid and bilirubin were identified and generally correspond with some of the previous reports of studies in Chinese and other ethnic groups. / The key findings of the study are as follows: 1. The polymorphisms most highly associated with the low-density lipoprotein cholesterol (LDL-C) response were 421C>A in the ATP-binding cassette G2 (ABCG2) gene (P=9.2x10 -7), followed by 18281G>A (V257M) in the flavin-containing monooxygenase 3 (FMO3) gene (P=0.0002), 1421C>G in the lipoprotein lipase (LPL) gene (P=0.002), and rs4420638 in the apolipoprotein E/C-I/C-IV/C-II (APOE/C1/C4/C2) gene cluster (P=0.004). These genetic polymorphisms and having FH totally explained 13.6% of the variance in percentage change in LDL-C in response to rosuvastatin. The greater percentage reduction in LDL-C in patients with the ABCG2 421AA genotype compared to those with the ABCG2 421CC genotype was equivalent to at least doubling the dose of rosuvastatin. 2. Three SNPs (glucokinase regulator [ GCKR] rs1260326, apolipoprotein AS [APOA5] -1131T>C and the solute carrier organic anion transporter 1B1 [SLCO1B1] 521T>C) tended to be associated with percentage changes in high-density lipoprotein cholesterol (HDL-C) (P&lt;0.05), but none of these reached the overall significance level. In multivariate stepwise regression analysis, baseline HDL-C (P=1.6x10 -6), having diabetes (P=0.0004) or RA (P=0.002) and the SLCO1B1 521T>C polymorphism (P=0.03) were determinants of HDL-C responses, contributing 9.9% of the variance in percentage change in HDL-C, but the genetic factors only contributed to 0.8% of the variance. 3. The triglyceride response to rosuvastatin was highly variable and was strongly related to baseline levels. The diacylglycerol acyltransferase-2 (DGAT2) rs10899113 C>T polymorphism tended to be associated with reduced triglyceride response in a gene-dose dependent manner. However, in multivariate stepwise regression analysis, baseline triglyceride level was the only factor that strongly related to the triglyceride response, explaining 14.4% of the variance. 4. This study has also analyzed relationships between on-treatment plasma hsCRP concentrations and cardiovascular risk factors and 14 single nucleotide polymorphisms in CRP and other candidate genes, which showed that central obesity, low HDL-C and CRP polymorphisms are major determinants of higher hsCRP levels in Chinese patients on treatment with rosuvastatin. 5. The association between genetic polymorphisms and lipid traits were analyzed in FH and non-FH patients separately due to their different lipid profiles. The analysis has shown that there were different genetic predictors of lipid levels in patients with and without FH and that more genetic factors appeared to affect the baseline lipid levels in patients with FH compared to non-FH patients, suggesting complex interactions between genetic and environmental factors and plasma cholesterol levels in patients with and without FH. 6. The SLC2A9 (solute carrier family 2, member 9) rs1014290 T>C was significantly associated with plasma uric acid levels in a gene-dose dependent manner (P=1.0x10-5) and the relationship was more pronounced in women or in patients without hypertension than in men or patients with hypertension. The ABCG2 421 C>A did not show a significant effect on uric acid levels. 7. The UGT1A1 (uridine diphosphate glucuronosyltransferases family, polypeptide A1) variants *28 (P=1.5x10 -9) and *6 (P=2.2x10-7) were independently associated with increased baseline bilirubin levels. Polymorphisms in SLCO1B1 did not appear to affect bilirubin levels in this study. / Hu, Miao. / Adviser: Brian Tomlinson. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 230-264). / 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.
293

Mechanisms and treatment options of chronic graft dysfunction : Experimental and clinical studies

Zezina, Lilija January 2001 (has links)
Chronic graft dysfunction (CGD) is an important post-transplant complication. CGD can be considered as an impaired repair process, which ultimately leads to the loss of graft function.To study non-immunological factors contributing to the development of CGD in kidney grafts we used in vitro and in vivo models, and clinical studies. We studied the actions of hyperlipidemia in vitro. LDL induced increased expression of TGF-β1 and TGF-β receptors type I and type II. Smad2 phosphorylation could be induced by conditioned medium from mesangial cells incubated with LDL. The effects of Fluvastatin and AT1 receptor blocker Candesartan cilexetil on aortic graft arteriosclerosis in the rat were evaluated. Fluvastatin neither alone nor in combination with Cyclosporine A affected allograft remodelling, but reduced neointima formation in isografts. Candesartan cilexetil treatment reduced graft arteriosclerosis. The effect is explained by the reduction of TGF-β1 expression. We investigated the effects of Carvedilol in patients with CGD. Carvedilol failed to alter the CGD progression despite the efficient control of blood pressure, and a beneficial effect on lipid pattern and oxidation. Close control of CyA blood levels is recommended due to interaction between CyA and Carvedilol. Measurement of Ab-oxLDL in kidney graft recipients demonstrated that these patients had lower Ab-oxLDL levels as compared with the control group. Decreased Ab-oxLDL levels were associated with graft loss due to acute rejection and with ischemic heart disease. In this thesis we have addressed several important complex issues, which are interconnected: (1) development of chronic graft dysfunction (2) lipoproteins and their role in inducing pathological conditions like atherosclerosis and graft damage, (3) oxidation, (4) TGF-β and its' role in different pathological conditions, including renal and vascular damage.
294

FC WInf: Flipped Classroom in der Wirtschaftsinformatik

Lorenz, Anja, Einert, Annett, Dinter, Barbara 01 October 2012 (has links) (PDF)
Szenarien mit Blended-Learning-Charakter sind Alltag an deutschen Hochschulen: Insbesondere durch die Verbreitung von Learning-Management- Systemen, in Sachsen namentlich „OPAL“, können Lehrveranstaltungen über die Präsenzveranstaltungen hinaus in nahezu allen Fachbereichen um computergestützte Lerneinheiten ergänzt werden. Nach der Etablierung von Web Based Trainings als typische digitale Ergänzungsmodule streben einige didaktische Konzepte die verstärkte Abstimmung von Präsenz- und Onlinephase an. In der jüngeren Zeit wurde vor allem die Idee des Flipped Classroom (auch Inverted Classroom genannt) diskutiert. Hierbei wird die traditionelle Aufteilung der Lehr-Lern-Aktivitäten, bei der die Wissensvermittlung in den Präsenzveranstaltungen und die Vertiefung des Gelernten in Übungen zu Hause stattfinden, vertauscht. Stattdessen erwerben die Studierenden das nötige Wissen online und im Vorfeld der Präsenzphase, in der dann mithilfe komplexer Beispiele und unter aktiver Einbeziehung der Studierenden das Verständnis gefestigt und durch den Lehrenden unterstützt angewendet werden kann. Auch die Großveranstaltung „Grundlagen der Wirtschaftsinformatik“ (GWI) an der TU Chemnitz soll im Übungsbetrieb durch ein Flipped-Classroom-Konzept verbessert werden. Hierfür werden bestehende Aufgaben mithilfe einer Fachlandkarte und der Bewertung der jeweiligen Lehrziele zu einem Online-Materialien-Pool aufgebaut. Die Präsenzphase soll zur stärkeren Einbeziehung der Studierenden in Form eines aktiven Plenums abgehalten werden.
295

Rab-domain dynamics in endocytic membrane trafficking / Zur Dynamik von Rab-Domänen während endozytotischer Transportprozesse

Rink, Jochen C. 26 April 2005 (has links) (PDF)
Eukaryotic cells depend on cargo uptake into the endocytic membrane system, which comprises a functionally interconnected network of endosomal compartments. The establishment and maintenance of such diverse compartments in face of the high rates of exchange between them, poses a major challenge for obtaining a molecular understanding of the endocytic system. Rab-GTPases have emerged as architectural key element thereof: Individual family members localize selectively to endosomal compartments, where they recruit a multitude of cytoplasmic effector proteins and coordinate them into membrane sub-domains. Such &amp;quot;Rab-domains&amp;quot; constitute modules of molecular membrane identity, which pattern the endocytic membrane system into a mosaic of Rab-domains. The main objective of this thesis research was to link such &amp;quot;static&amp;quot; mosaic-view with the highly dynamic nature of the endosomal system. The following questions were addressed: How are neighbouring Rab-domains coordinated? Are Rab-domains stable or can they undergo assembly and disassembly? Are the dynamics of Rab-domains utilized in cargo transport? The first part of this thesis research focused on the organization of Rab-domains in the recycling pathway. Utilizing Total Internal Reflection (TIRF) microscopy, Rab11-, but neither Rab4- nor Rab5-positive vesicles were observed to fuse with the plasma membrane. Rab4-positive membranes, however, could be induced to fuse in presence of Brefeldin A. Thus, these experiments complete the view of the recycling pathway by the following steps: a) Rab11-carriers likely mediate the return of recycling cargo to the surface; b) such carriers are presumably generated in an Arf-dependent fission reaction from Rab4-positive compartments. Rab11-chromatography was subsequently carried out in the hope of identifying Rab11-effectors functioning at the Rab4-Rab11 domain interface. An as yet uncharacterized ubiquitin ligase was identified, which selectively interacts with both Rab4 and Rab11. Contrary to expectations, however, the protein (termed RUL for *R*ab interacting *U*biquitin *L*igase) does not function in recycling,but appears to mediate trafficking between Golgi/TGN and endosomes instead.In order to address the dynamics of Rab-domains, fluorescently tagged Rab-GTPases were imaged during cargo transport reactions in living cells. Herefore high-speed/long-term imaging procedures and novel computational image analysis tools were developed. The application of such methodology to the analysis of Rab5-positive early endosomes showed that a) The amount of Rab5 associated with individual endosomes fluctuates strongly over time; b) such fluctuations can lead to the &amp;quot;catastrophic&amp;quot; loss of the Rab5-machinery from membranes; c) Rab5 catastrophe is part of a functional cycle of early endosomes, involving net centripetal motility, continuous growth and increase in Rab5 density. Next, the relevance of Rab5 catastrophe with respect to cargo transfer into either the recycling- or degradative pathway was examined. Recycling cargo (transferrin) could be observed to exit Rab5-positive early endosomes via the frequent budding of tubular exit carriers. Exit of degradative cargo (LDL) from Rab5-positive endosomes did not involve budding, but the rapid loss of Rab5 from the limiting membrane.Rab5-loss was further coordinated with the concomitant acquisition of Rab7, suggesting &amp;quot;Rab conversion&amp;quot; as mechanism of transport between early- and late endosomes.Altogether, this thesis research has shown that first, Rab-machineries can be acquired and lost from membranes. Second, such dynamics provide a molecular mechanism for cargo exchange between endosomal compartments. Jointly, these findings lead to the concept of Rab-domain dynamics modulation in /trans/ between neighbouring domains as mechanistic principle behind the dynamic organization of membrane trafficking pathways.
296

Antigen interaction with B cells in two proliferative disorders : CLL and MGUS /

Hellqvist, Eva, January 2010 (has links) (PDF)
Diss. (sammanfattning) Linköping : Linköpings universitet, 2010. / Härtill 4 uppsatser.
297

Elaboracao e avaliacao da eficacia do sistema de pontos de um instrumento de orientacao alimentar como ferramenta para intervencoes dieteticas em individuos hiperlipidemicos

Abreu, Edeli Simioni de. January 2003 (has links)
Doutor -- Universidade de Sao Paulo. Faculdade de Saude Publica. Departamento de Nutricao, Sao Paulo, 2003.
298

Estudos dos polimorfismos dos genes da apolipoproteína E (ApoE) e do receptor de LDL (RLDL - A370T) em indivíduos jovens pertencentes ao estudo do Rio de Janeiro em seguimento de 28 Anos / Studies of gene polymorphisms of apolipoprotein E (ApoE) and LDL receptor (RLDL - A370T) in young individuals belonging to the study of Rio de Janeiro in follow-up of 28 Years

Rossana Ghessa Andrade de Freitas 23 August 2011 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Estudos demonstram a associação de alterações da apolipoproteína E (ApoE) e do receptor do LDL (RLDL) com a ocorrência de doenças cardiovasculares e dislipidemia. O objetivo principal deste trabalho foi investigar a associação entre genótipos diferenciais da ApoE e do RLDL com a persistência de alterações de variáveis lipídicas em indivíduos jovens acompanhados há 28 anos no Estudo do Rio de Janeiro (ERJ). Através de um estudo longitudinal, tipo coorte, investigou-se 56 indivíduos (35M) em três avaliações. Em A1 (13.301.53 anos), A2 (22.091.91 anos) e A3 (31.231.99). Nas três ocasiões foi realizada avaliação clínica. Em A2 e A3 foram dosados colesterol total, HDL, LDL e triglicerídeos. Em A3 acrescentou-se o estudo dos polimorfismos genéticos da ApoE e do RLDL. Os fragmentos de interesse neste estudo foram amplificados por PCR (polymerase chain reaction) e os genótipos foram identificados através de reações de restrição. As frequências genotípicas de ApoE foram &#949;3/&#949;3 (62,5%), &#949;3/&#949;4 (25%), &#949;2/&#949;3 (5,4%) ,&#949;2/&#949;4 (5,4%) e &#949;4/&#949;4 (1,8%) e para os genótipos de RLDL foram AA (85,7%), AT (12,5%) e TT (1,8%). O genótipo &#949;2/&#949;2 não foi observado. A análise da distribuição dos genótipos de ApoE segundo a permanência de dislipidemia mostrou que todos os indivíduos com genótipo de ApoE dos tipos &#949;2/&#949;4 e &#949;4/&#949;4 mantiveram pelo menos um lípide alterado em A2 e A3 entretanto, todos os indivíduos com genótipo de ApoE do tipo &#949;2/&#949;3 não apresentaram lípides alterados em A2 e A3. Para o genótipo do RLDL não houve diferença significativa. Quando analisadas isoladamente, não foi identificado nenhum resultado significativo em A2 e/ou A3 associado a estes genótipos. O polimorfismo do gene da ApoE esteve associado à permanência de dislipidemia em indivíduos jovens acompanhados em estudo de seguimento longitudinal / Studies have shown the association of changes in the apolipoprotein E (ApoE) and LDL receptor (LDLR) with the occurrence of cardiovascular diseases and dyslipidemia. The objective of this study was to investigate the association between different ApoE genotypes and LDLR with the persistence of changes in lipid variables in young individuals followed-up 28 years in the study of Rio de Janeiro (ERJ). Through a longitudinal study cohort, 56 subjects (35M) in A1(13.30 1.53 years), A2(22.09 1.91 years) and A3(31.23 1.99) were investigated. On all three occasions clinical evaluation was conducted. In A2 and A3: total cholesterol, HDL, LDL and triglycerides. In A3 was added to the study of genetic polymorphisms of the ApoE and LDLR. The fragments of interest in this study were amplified by PCR (polymerase chain reaction) and the genotypes were identified by reaction with the restriction enzyme HhaI and HaeIII for ApoE and LDLR polymorphisms, respectively. ApoE genotypes were identified as &#949;3/&#949;3 (62.5%), &#949;3/&#949;4 (25%), &#949;2/&#949;3 (5.4%), &#949;2/&#949;4 (5.4%) and &#949;4/&#949;4 (1.8%) and the LDLR genotypes identified as AA (85.7%), AT (12.5%) and TT (1.8%). &#949;2/&#949;2 genotype was not observed. The analysis of the distribution of ApoE and LDLR genotypes according to the permanence of the dyslipidemia in the study sample showed that all individuals with the ApoE genotype &#949;2/&#949;4 and &#949;4/&#949;4 kept at least one lipid changes in A2 and A3 and all individuals ApoE genotype &#949;2/&#949;3 had not altered lipids in A2 and A3, while for RLDL genotype no difference was found. When analyzed individually, no lipid variable altered in A2 and/or A3, associated with these genotypes, were found. The ApoE gene polymorphism was associated with the permanence of dyslipidemia in young individuals in a longitudinal follow-up study
299

Estudos dos polimorfismos dos genes da apolipoproteína E (ApoE) e do receptor de LDL (RLDL - A370T) em indivíduos jovens pertencentes ao estudo do Rio de Janeiro em seguimento de 28 Anos / Studies of gene polymorphisms of apolipoprotein E (ApoE) and LDL receptor (RLDL - A370T) in young individuals belonging to the study of Rio de Janeiro in follow-up of 28 Years

Rossana Ghessa Andrade de Freitas 23 August 2011 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Estudos demonstram a associação de alterações da apolipoproteína E (ApoE) e do receptor do LDL (RLDL) com a ocorrência de doenças cardiovasculares e dislipidemia. O objetivo principal deste trabalho foi investigar a associação entre genótipos diferenciais da ApoE e do RLDL com a persistência de alterações de variáveis lipídicas em indivíduos jovens acompanhados há 28 anos no Estudo do Rio de Janeiro (ERJ). Através de um estudo longitudinal, tipo coorte, investigou-se 56 indivíduos (35M) em três avaliações. Em A1 (13.301.53 anos), A2 (22.091.91 anos) e A3 (31.231.99). Nas três ocasiões foi realizada avaliação clínica. Em A2 e A3 foram dosados colesterol total, HDL, LDL e triglicerídeos. Em A3 acrescentou-se o estudo dos polimorfismos genéticos da ApoE e do RLDL. Os fragmentos de interesse neste estudo foram amplificados por PCR (polymerase chain reaction) e os genótipos foram identificados através de reações de restrição. As frequências genotípicas de ApoE foram &#949;3/&#949;3 (62,5%), &#949;3/&#949;4 (25%), &#949;2/&#949;3 (5,4%) ,&#949;2/&#949;4 (5,4%) e &#949;4/&#949;4 (1,8%) e para os genótipos de RLDL foram AA (85,7%), AT (12,5%) e TT (1,8%). O genótipo &#949;2/&#949;2 não foi observado. A análise da distribuição dos genótipos de ApoE segundo a permanência de dislipidemia mostrou que todos os indivíduos com genótipo de ApoE dos tipos &#949;2/&#949;4 e &#949;4/&#949;4 mantiveram pelo menos um lípide alterado em A2 e A3 entretanto, todos os indivíduos com genótipo de ApoE do tipo &#949;2/&#949;3 não apresentaram lípides alterados em A2 e A3. Para o genótipo do RLDL não houve diferença significativa. Quando analisadas isoladamente, não foi identificado nenhum resultado significativo em A2 e/ou A3 associado a estes genótipos. O polimorfismo do gene da ApoE esteve associado à permanência de dislipidemia em indivíduos jovens acompanhados em estudo de seguimento longitudinal / Studies have shown the association of changes in the apolipoprotein E (ApoE) and LDL receptor (LDLR) with the occurrence of cardiovascular diseases and dyslipidemia. The objective of this study was to investigate the association between different ApoE genotypes and LDLR with the persistence of changes in lipid variables in young individuals followed-up 28 years in the study of Rio de Janeiro (ERJ). Through a longitudinal study cohort, 56 subjects (35M) in A1(13.30 1.53 years), A2(22.09 1.91 years) and A3(31.23 1.99) were investigated. On all three occasions clinical evaluation was conducted. In A2 and A3: total cholesterol, HDL, LDL and triglycerides. In A3 was added to the study of genetic polymorphisms of the ApoE and LDLR. The fragments of interest in this study were amplified by PCR (polymerase chain reaction) and the genotypes were identified by reaction with the restriction enzyme HhaI and HaeIII for ApoE and LDLR polymorphisms, respectively. ApoE genotypes were identified as &#949;3/&#949;3 (62.5%), &#949;3/&#949;4 (25%), &#949;2/&#949;3 (5.4%), &#949;2/&#949;4 (5.4%) and &#949;4/&#949;4 (1.8%) and the LDLR genotypes identified as AA (85.7%), AT (12.5%) and TT (1.8%). &#949;2/&#949;2 genotype was not observed. The analysis of the distribution of ApoE and LDLR genotypes according to the permanence of the dyslipidemia in the study sample showed that all individuals with the ApoE genotype &#949;2/&#949;4 and &#949;4/&#949;4 kept at least one lipid changes in A2 and A3 and all individuals ApoE genotype &#949;2/&#949;3 had not altered lipids in A2 and A3, while for RLDL genotype no difference was found. When analyzed individually, no lipid variable altered in A2 and/or A3, associated with these genotypes, were found. The ApoE gene polymorphism was associated with the permanence of dyslipidemia in young individuals in a longitudinal follow-up study
300

Modeling Of Transport Phenomena In Arteries

Golatkar, Poorva 09 1900 (has links) (PDF)
Atherosclerosis is an arterial disease that occurs due to the build-up of lipids, cholesterol and other substances in the arterial wall, collectively called plaque, leading to narrowing of the vessel lumen and, in time, disruption to the blood supply. The study of flow through atherosclerotic vessels is especially important since plaques not only cause a reduction in the vessel lumen but can rupture from the arterial wall, causing a blood clot in the vessel that may ultimately lead to heart attack or a stroke. Elevated level of oxidated low density lipoprotein (LDL) is a known risk factor associated with the genesis of atherosclerosis in arterial walls. Previous studies reported in literature have explored the transport of LDL through the arterial wall using analytical and mathematical models. In this work, we have presented a computational framework for the study of LDL transport in the lumen and the porous arterial wall. We have employed a four-layer arterial wall model and used governing equations to model the transport of LDL. We have used physiological parameters for the wall layers from literature and have validated the model based on the calculated filtration velocities and LDL concentration profiles in the arterial wall. We have further used this established model to study the effect of change in permeability and pressure on the LDL concentration. We have also studied the effect of pulsatile flow on the transport of LDL through the porous walls to examine the validity of the initial assumption of steady state and have seen that pulsation increases the time averaged net flux of LDL species by about 20%. We have next modeled a drug-eluting stent (DES), which is one of the popular remedies to cure atherosclerosis. The validation of DES model is followed by a combined study to analyze the effect of stent placement on LDL transport. Although there is no chemical reaction between the drug and LDL, we have noticed recirculation zones near the stent strut which result in accumulation of LDL molecules in the arterial wall. Future studies are aimed at incorporating variable porosity and permeability and a stenosed region in the geometry. The deformation of arterial wall due to pulsatile blood flow may lead to alteration of wall properties, which can give a realistic view of macromolecular transport.

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