Minimum miscibility pressure (MMP) is a key parameter in the design of gas flooding. There are experimental and computational methods to determine MMP. Computational methods are fast and convenient alternatives to otherwise slow and expensive experimental procedures. This research focuses on the computational aspects of MMP estimation. It investigates the shortcomings of the current computational models and offers ways to improve the robustness of MMP estimation. First, we develop a new mixing cell method of estimating MMP that, unlike previous "mixing cell" methods, uses a variable number of cells and is independent of gas-oil ratio, volume of the cells, excess oil volumes, and the amount of gas injected. The new method relies entirely on robust P-T flash calculations using any cubic equation-of-state (EOS). We show that mixing cell MMPs are comparable with those of other analytical and experimental methods, and that our mixing cell method finds all the key tie lines predicted by MOC; however, the method proved to be more robust and reliable than current analytical methods. Second, we identify a number of problems with analytical methods of MMP estimation, and demonstrate them using real oil characterization examples. We show that the current MOC results, which assume that shocks exist from one key tie line to the next may not be reliable and may lead to large errors in MMP estimation. In such cases, the key tie lines determined using the MOC method do not control miscibility, likely as a result of the onset of L₁-L₂-V behavior. We explain the problem with a simplified pseudo-ternary model and offer a procedure for determining when an error exists and for improving the results. Finally, we present a simple mathematical model for predicting the MMP of contaminated gas. Injection-gas compositions often vary during the life of a gasflood because of reinjection and mixing of fluids in situ. Determining the MMP by slim-tube or other methods for each possible variation in the gas-mixture composition is impractical. Our method gives an easy and accurate way to determine impure CO₂ MMPs for variable field solvent compositions on the basis of just a few MMPs. Alternatively, the approach could be used to estimate the enrichment level required to lower the MMP to a desired pressure. / text

Cartilage regeneration is one of the most widely studied areas in tissue-engineering. Despite significant progress, most efforts to date have only focused on generating homogenous tissues whose bulk properties are similar to articular cartilage. However, anatomically and functionally, articular cartilage consists of four spatially distinct regions: the superficial, transitional, deep, and calcified zones. Each zone is characterized by unique extra-cellular matrix (ECM) compositions, mechanical properties, and cellular organization. The ECM is primarily composed of type II collagen and glycosaminoglycans (GAGs), whose relative concentrations vary between zones and therefore lead to distinctive mechanical properties. One of the major unsolved challenges in engineering cartilage has been the inability to regenerate tissue that mimics the zonal architecture of articular cartilage. Recent studies have attempted to imitate this spatial organization using zone-specific chondrocytes isolated from donor animal cartilage. Directed differentiation of a single stem population into zonally organized native-like articular cartilage has not yet been reported. This dissertation reports that hydrogels, incorporating both synthetic and natural polymers as well as cell-induced degradability, are suitable for generating zone-specific chondrogenic phenotypes from a single MSC population. Specifically, cues provided from the unique combinations of chondroitin sulfate (CS), hyaluronic acid (HA), and MMP-sensitive peptide (MMP-pep) within a PEG-based hydrogel, direct the chondrogenic differentiation of MSCs. The findings of this dissertation demonstrate the capability of creating native-like and mechanically relevant articular cartilage consisting of zone specific layers. This ability provides a new direction in cartilage tissue engineering and could be invaluable for cartilage repair if incorporated with current minimally invasive surgical techniques. / text

El adenocarcinoma ductal pancreático (PDAC) es la quinta causa de muerte por cáncer en los países desarrollados y uno de los tumores humanos más agresivos. A pesar del papel clave de la angiogénesis -la formación de nuevos vasos a partir de otros preexistentes- en la progresión y metástasis de muchos tumores, su papel en PDAC ha sido poco caracterizado. El activador tisular del plasminógeno (tPA), una proteína multifuncional que regula numerosas funciones celulares, ejerce efectos proangiogénicos en modelos in vivo de PDAC, aunque no se han analizado los mecanismos moleculares responsables de estos efectos. Esta tesis trata de identificar el papel de tPA en la angiogénesis del PDAC, así como de descubrir los factores responsables de la sobreexpresión de tPA en cáncer de páncreas. En primer lugar, hemos demostrado que los efectos pro-angiogénicos de tPA pueden ser tanto directos como indirectos. Por un lado, aunque tPA no cambia los niveles de moléculas pro-angiogénicas como VEGF, TGF-b, IL-1 o IL-8 producidas por las células tumorales o endoteliales, sí que induce la sobreexpresión y activación de MMP-9, una metaloproteasa implicada en promover angiogénesis, sugiriendo por tanto que esta proteína puede mediar de forma indirecta los efectos proangiogénicos de tPA. Por otro lado, hemos encontrado que tPA, de forma independiente de su actividad catalítica, promueve directamente la proliferación, migración y tubulogénesis de las células endoteliales. Estos efectos son mediados por la activación en estas células de las rutas de señalización ERK1/2, AKT y JNK. Además, mediante siRNA o inhibidores químicos, hemos encontrado que Annexina A2, Galectina-1 y EGFR son necesarios para la activación de la señalización inducida por tPA en células endoteliales. Finalmente, hemos visto que citoquinas inflamatorias e hipoxia, dos eventos asociados a PDAC y además inductores de angiogénesis, dan lugar a un fuerte incremento de los niveles de tPA en células tumorales pancreáticos. Todos estos datos apoyan un mecanismo de retroalimentación positiva entre estímulos proangiogénicos presentes en las células tumorales y el estroma, y el incremento de la molécula proangiogénica tPA. / Pancreatic ductal adenocarcinoma (PDAC) is the fifth leading cause of cancer death in the developed countries and one of the most aggressive human tumors. Despite the key contribution of angiogenesis – the growth of new vessels from pre-existing ones- to the progression and spread of many cancers, its role in PDAC has been poorly characterized. Tissue plasminogen activator (tPA), a multifunctional protein regulating a broad range of cellular functions, has been reported to exert pro-angiogenic effects in in vivo models of PDAC, although the underlying molecular mechanism has not been analyzed. This work aims to elucidate the role of tPA in the angiogenesis of PDAC as well as to identify the factors responsible for tPA increase in pancreatic cancer. First, we demonstrated that tPA pro-angiogenic effects are both indirect and direct. On the one hand, tPA does not change the levels of the pro-angiogenic molecules VEGF, TGF-b, IL-1 or IL-8 produced by pancreatic tumoral cells or endothelial cells, but it is involved in MMP-9 –a potent stimulator of angiogenesis- upregulation and activation in pancreatic and endothelial cells, suggesting that this matrix metalloproteinase can indirectly mediate tPA angiogenic effects. On the other hand, we found that tPA, in a catalytic-independent way, directly promotes endothelial cell proliferation, migration and tubulogenesis. These direct effects of tPA are mediated by activation of ERK1/2, AKT and JNK signaling pathways in endothelial cells. In addition, using siRNA technology or chemical inhibitors, we found that AnnexinA2, Galectin-1 and EGFR are required for tPA-mediated signaling activation in endothelium. Finally, we found that inflammatory cytokines and hypoxia, two hallmarks of PDAC and also angiogenic stimuli, lead to a sharp increase in tPA levels in pancreatic tumoral cells. These data support a feed-back loop between proangiogenic stimuli present in both tumoral and stromal cells and the increase of the proangiogenic molecule tPA.

Les cancers broncho-pulmonaires à petites cellules (CBPPC), tumeurs endocrines représentant 20% des cancers pulmonaires, sont fortement associés au tabagisme. Ils sont très agressifs en raison de leur progression rapide et de la présence de métastases souvent présentes au moment du diagnostic. Moins de 10% des patients sont opérables et la plupart des échantillons de tumeurs sont recueillis par endoscopie bronchique ou par médiastinoscopie. Dans ce travail de thèse, nous avons montré que l’expression du TFPI-2, un gène suppresseur de tumeur, était diminué dans 65% des cas de CBPPC. Afin d’étudier l’impact du TFPI-2 sur la progression tumorale, nous avons préalablement développé un modèle orthotopique murin de CBPPC qui mime le développement de ce type de cancer pulmonaire. Des cellules NCI-H209, n’exprimant pas le TFPI-2, ont été préalablement transfectées pour exprimer la luciférase et la croissance tumorale a été suivie par imagerie de bioluminescence. L’expression du TFPI-2 a ensuite été restaurée dans ces cellules et nous avons montré que la croissance tumorale était alors réduite. Cet effet peut s’expliquer par une diminution de la prolifération des cellules exprimant le TFPI-2, associée à un arrêt du cycle cellulaire en phase G1/S dû à l’expression de p15 et de p27 et à une induction de l’apoptose. Nous avons aussi démontré que lorsque le TFPI-2 est surexprimé, les transcrits et les protéines MMP-1 et -3 sont diminuées, tout comme la phosphorylation des protéines de la voie des MAP Kinases impliquées dans l’induction des transcrits de ces MMP. Cette corrélation entre l’expression du TFPI-2 et la diminution de celle de la MMP-1 a été retrouvée dans 35% des échantillons de CBPPC humains. Ces résultats suggèrent que l’inactivation du TFPI-2 dans les CBPPC peut favoriser le développement de ce cancer. Enfin, nous avons également démontré, pour la première fois que le TFPI-2 peut aussi inhiber la kallicréine 12, une protéase à sérine potentiellement anti-angiogénique. L’ensemble de ces données suggèrent que le TFPI-2 peut être un potentiel biomédicament capable de limiter la progression des carcinomes pulmonaires à petites cellules. / Small Cell Lung Cancer (SCLC) is the most common neuroendocrine tumour of the lung (15% of cases) and is strongly associated with smoking. It is characterised by tumours that grow rapidly with early metastases. Less than 10% of patients with SCLC have a resectable tumour, thus surgical specimens are scarce and most tumour samples come from small biopsies obtained during bronchial endoscopy or mediastinoscopy. In this study, low levels of TFPI-2 expression were found in 65% of patients with SCLC. To study the impact of TFPI-2 in tumour progression, we first developed a clinically relevant animal model that resembles various stages of human SCLC. NCI-H209 cells, not expressing TFPI-2, were genetically modified to express firefly luciferase and the growth of the tumour was sensitively followed by bioluminescence imaging. TFPI-2 was then overexpressed in these cells and we showed that TFPI-2 inhibited lung tumour growth. Such inhibition could be explained in vitro by a decrease in tumour cell proliferation, blockade of G1/S phase cell cycle transition due to p15 and p27 expression, and an increase in apoptosis shown in NCI-H209 cells expressing TFPI-2. We also demonstrated that TFPI-2 upregulation in NCI-H209 cells decreased MMP expression, particularly by downregulating MMP-1 and MMP-3. Moreover, TFPI-2 inhibited phosphorylation of the MAPK signalling pathway proteins involved in the induction of MMP transcripts, among which MMP-1 was predominant in SCLC tissues and was inversely expressed with TFPI-2 in 35% of cases. These results suggest that downregulation of TFPI-2 expression could favour the development of SCLC. Finally, we also demonstrated for the first time that TFPI-2 could inhibit the kallikrein 12, an anti-angiogenic serine proteinase. Altogether, these results suggest that TFPI-2 could be a new potent therapeutic agent to control SCLC tumour progression in SCLC.

Made available in DSpace on 2016-06-02T20:19:08Z (GMT). No. of bitstreams: 1 1843.pdf: 1192914 bytes, checksum: 124690357d5fd2c475721de4dd0a5c76 (MD5) Previous issue date: 2008-02-27 / Financiadora de Estudos e Projetos / As lesões musculares são bastante comuns na prática esportiva e na reabilitação ortopédica. A terapia laser de baixa intensidade (TBLI) apresenta bons resultados no tratamento de diferentes afecções que acometem o tecido muscular esquelético, entretanto a fluência utilizada neste tratamento ainda é controversa. Este estudo tem como objetivo verificar os efeitos de diferentes fluências do laser de λ= 830nm no processo de regeneração muscular. Foram utilizados ratos machos Wistar, distribuídos em 8 grupos de 7 animais cada: grupo controle (C); grupos em que os músculos tibial anterior direito (TAD) foram apenas irradiados com laser diodo (λ= 830nm) com fluência de 4J/cm 2 (4J), 8J/cm 2 (8J) e 16J/cm2 (16J); grupo lesão (CL), no qual o músculo foi submetidos à criolesão; grupos em que os músculos TAD foram submetidos à criolesão e tratados com laser diodo (λ= 830nm) com fluência de 4J/cm 2 (L6J), 8J/cm 2 (L8J), 16J/cm2 (L16J). A irradiação teve início 24horas após a lesão por 5 dias consecutivos de forma pontual, sobre a área de lesão. No sexto dia após a lesão, os animais foram eutanaziados. O sangue foi coletado para avaliação dos níveis plasmáticos de NOx-, através da técnica de Griess. A avaliação muscular contou com análises histológicas da área de lesão (Hematolina e Eosina e Fosfatase Ácida). Além disso, a atividadade da COX-2 foi analisada pelas técnicas de Biotin Switch e a atividade e expressão protéica de MMP-2 por técnica de Zimografia e Western Blotting, respectivamente. Os resultados mostraram que houve uma diminuição da área de lesão conforme aumento da fluência do laser (8J/cm2 e 16J/cm2); um aumento nos níveis plasmáticos de NOx- em todos grupos lesados e uma diminuição apenas no grupo L16J em relação aos grupos lesados; a COX-2 foi ativada apenas nos grupos CL e L4J; a atividade da MMP-2 aumentou em todos grupos lesados e a expressão protéica aumentou nos grupos L8J e L16J. Conjuntamente os resultados permitem concluir que as fluências de 8J/cm2 e 16J/cm2 foram as que apresentaram um melhor desempenho na TLBI nos processos que envolvem regeneração do músculo esquelético de ratos. Este estudo trouxe dados importantes para o uso clínico, pois confrontou variáveis importantes como o comportamento de diferentes fluências no processo de regeneração muscular, proporcionando verificar um protocolo de aplicação mais seguro e eficaz.

1 Abstract Liver fibrosis is a condition described by extensive accumulation of scar tissue in the liver. With further progression, it leads to cirrhosis or even to hepatocellular carcinoma. Liver fibrosis accompanies every chronic liver disease and its prevalence in adult European population is estimated to be around 4%. During my dissertation work, I studied the function of three members of Metzincin family of metalloproteinases - ADAM17, ADAM10 and MMP-19, in liver fibrosis and liver regeneration using mouse genetic models. ADAM17 and ADAM10 are important regulators of signalling pathways which are involved in immune response as well as differentiation. Both proteases are able to cleave ectodomains of their substrates from cell membrane, affecting bioavailability of ligands and functionality of receptors. Several of their substrates are involved in liver pathologies. MMP-19 on the other hand, is a metalloprotease mainly involved in extracellular matrix cleavage, important process in fibrosis development, as well as resolution of fibrosis. Our results demonstrate that ablation of ADAM10 results in increased susceptibility to liver fibrosis in mice, both spontaneous and toxin induced. ADAM10 deficiency affected biliary epithelium, as we detected higher markers of biliary damage in serum of ADAM10 deficient...

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Kronisk parodontit orsakar vävnadsdestruktion till följd av matrixmetalloproteinasaktivitet. Dessa enzym härrör från värdcellerna och är en del av det immunologiska svaret på bakteriella virulensfaktorer. Grönt te har studerats för sina hälsofrämjande egenskaper, som omfattar bland annat anti-inflammatoriska effekter. Effekten beror delvis på enzyminhibering av tepolyfenoler. Syftet med denna studie var att ytterligare undersöka den inhiberande effekten av grönt te, med fokus på enzymatisk aktivitet i gingivalvätska från patienter med parodontal sjukdom. Patienter med kronisk parodontit valdes ut för att delta i studien. Gingivalvätska extraherades med mikropipetter från patienternas gingivala sulci. Proverna behandlades med grönt te och jämfördes med obehandlade prover från samma försöksperson. Fluorescens proteasanalys med kasein som substrat utfördes på fjorton prover för att detektera skillnader i kaseinolytisk aktivitet. Zymogramanalys med användning av gelatin som substrat utfördes på fyra prover, för att undersöka skillnader i gelatinolytisk aktivitet och analysera molekylvikter för de olika enzymerna. Den fluorometriska analysen visade en signifikant lägre enzymaktivitet i prover med tillsatt grönt te jämfört med obehandlade prover (p<0.001). Zymogramanalysen visade en skillnad i enzymaktivitet som var mest uttalad i banden för molekylär vikt runt 255 kDa, analogt med komplex av matrixmetalloproteinas-9. Sammanfattningsvis har det i denna studie påvisats att grönt te har en hämmande effekt på kaseinolytisk aktivitet och en mindre, mer specifik, hämmande effekt på gelatinasaktivitet. / Chronic periodontitis involves tissue destruction by matrix metalloproteinase, derived from the host cells, as part of the immunological response to bacterial virulence factors. Green tea has been studied for its health promoting properties, which includes anti-inflammatory effects. The effect is in part due to enzyme inhibition by tea polyphenols. The aim of this study was to further investigate the inhibitory effect of green tea, focusing on enzymatic activity in gingival crevicular fluid from patients with periodontal disease. Patients with chronic periodontitis were selected for participation in the study. Gingival crevicular fluid was extracted with micropipettes from the gingival sulci of the patients. Samples were treated with green tea and compared with untreated samples from the same subject. Fluorescence protease assay with casein as substrate was made using fourteen samples for detecting differences in caseinolytic activity. Zymogram assay using gelatin as substrate was done using four samples to test gelatinolytic activity and analyse molecular weights of the different enzymes. The fluorometric assay showed a significantly lower enzyme activity in samples mixed with green tea than untreated samples (p<0.001). The zymogram assay showed a difference in band strength which was most pronounced in the bands of molecular weight around 255 kDA, analogous to complexes of matrix metalloproteinase-9. In conclusion, green tea has been shown in this study to have a strong inhibitory effect on caseinolytic activity and a lesser, more specific, inhibitory effect on gelatinase activity.

Yes / Studies have been conducted to highlight the anti-inflammatory and immunosuppressive properties of synthetic cannabinoids as well as their potential for cartilage repair. Various wound healing techniques can be used to investigate the mechanisms of chondrocyte repair in monolayers or three dimensional tissues constructs. In this work the effect of WIN55, 212-2 (WIN-2) on nitric oxide (NO) and matrix metalloproteinase-2 (MMP-2) expressed by wounded chondrocyte monolayers was investigated. Moreover, expression of collagen type-I and type-II, fibronectin and S100 proteins were detected using immunofluorescence and quantitatively verified using ELISA based techniques following treatment with 1 μM and 2 μM of WIN-2. Treating chondrocytes with 1 μM of WIN-2 significantly increased expression of collagen type-II, fibronectin and S100, and significantly reduced collagen type-I expressions as compared to the control groups. On the other hand, both concentrations of WIN-2 significantly reduced the expression of the inflammation markers NO and MMP-2 in a dose dependent manner. These findings highlight the potential use of the synthetic cannabinoids for improving cartilage healing properties as well as acting as an anti-inflammatory agent which could be used to enhance tissue engineering protocols aimed at cartilage repair.