Chiu Hoi Shan Clarissa. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 110-126). / Abstracts in English and Chinese. / Abstract in English --- p.i / Abstract in Chinese --- p.iii / Acknowledgement --- p.iv / List of Abbreviations --- p.v / List of Tables --- p.vi / List of Figures --- p.viii / Introduction and Objectives / Hepatocellular Carcinoma / Epidemiology --- p.1 / Sex and Age --- p.1 / Geographic distibution --- p.2 / Risk factors of HCC --- p.2 / Mortality from liver cancer --- p.4 / Treatment for HCC --- p.4 / Tumor markers --- p.5 / Alpha-fetoprotein / Structure --- p.5 / Physiological Functions of AFP --- p.7 / Re-expression of AFP in Adult --- p.7 / Re-expression of AFP in HCC --- p.8 / Isoforms of AFP --- p.8 / Specific AFP isoform in HCC --- p.9 / Sialic Acid --- p.11 / Sialyltransferase / "Galβ 1,4GlcnAc α2,6-sialyitransferase" --- p.12 / "Characterization of ST2,6Gal I" --- p.12 / "Expression of ST2,6Gal I" --- p.12 / "General features of ST2,6Gal I Activity" --- p.15 / Relationship Between AFP isoforms and ST2，6Gal in Fetal Mouse Model --- p.15 / "Change in ST2,6GaI I Activity in Transgenic Mouse Models of HCC" --- p.16 / "Study of Activity of ST2,6Gal I in Colon Carcinoma" --- p.16 / Objective of the Project --- p.18 / Chapter Chapter 1 --- Formation of Monosialyated AFP by Hepatoma Cells / Chapter 1.1 --- Introduction --- p.21 / Chapter 1.2 --- Materials and Methods --- p.23 / Chapter 1.3 --- Results / Chapter 1.3.1 --- AFP obtained from cell culture --- p.34 / Chapter 1.3.2 --- IEF for AFP in cell culture medium --- p.34 / Chapter 1.3.3 --- SDS-PAGE analysis of AFP --- p.34 / Chapter 1.3.4 --- Stability of AFP isoforms after secreted to cell culture medium --- p.39 / Chapter 1.3.5 --- Comparison of the AFP isoforms between liver tissues and serum --- p.38 / Chapter 1.4 --- Discussion / Chapter 1.4.1 --- Origin of the extracellular msAFP - in vitro Model --- p.43 / Chapter 1.4.2 --- Origin of circulating msAFP - in vivo Model --- p.44 / Chapter 1.5 --- Conclusion --- p.46 / Chapter Chapter 2 --- "Presence of msAFP in the serum of HCC patient is a Consequence of Decrease in the Activity of ST2, / Chapter 2.1 --- Introduction --- p.47 / Chapter 2.2 --- Materials and Methods --- p.49 / Chapter 2.3 --- Results / Chapter 2.3.1 --- Semi-quantitation of msAFP --- p.61 / Chapter 2.3.2 --- Evaluation of the ST2，6Gal I Assay --- p.65 / Chapter 2.3.3 --- "Measurements and comparisons of the activity of ST2,6Gal I in non-tumor and tumor tissue" --- p.65 / Chapter 2.3.4 --- "Evaluation of the RT-PCR ELISA for semi-quantitation and comparisons of ST2,6Gal I mRNA levels" --- p.75 / Chapter 2.3.5 --- "Semi-quantitation and comparisons of ST2,6Gal I mRNA levels in the non-tumor and tumor tissues" --- p.84 / Chapter 2.3.6 --- Correlations between the markers --- p.87 / Chapter 2.4 --- Discussion / Chapter 2.4.1 --- "Overproduction of AFP, a possible cause for increased msAFP formation" --- p.99 / Chapter 2.4.2 --- "Decrease of ST2,Gal I activity, a possible cause for increased msAFP formation" --- p.100 / Chapter 2.4.3 --- "ST2,6Gal I activity in tumor is not regulated at transcriptional level" --- p.102 / General Discussion / Origin of blood stream msAFP --- p.103 / Physiological Mechanism for the formation of msAFP in HCC --- p.104 / Regulation of ST2，6Gal I activity in HCC --- p.105 / "Comparison between the ST2,6GaI I activities in human HCC and Colon Cancer" --- p.107 / Conclusion and Future studies / Conclusion --- p.108 / Future studies --- p.109 / References --- p.110

L’interface hôte/microbiote intestinal est un système d’interactions complexes dont le déséquilibre est associé au développement des maladies inflammatoires chroniques. Les traitements anti-TNFα sont très efficaces dans ces maladies, mais seulement chez certains patients. L’objectif de ce travail était de rechercher un lien entre composition du microbiote intestinal et réponse aux traitements anti-TNFα dans deux types de maladies inflammatoires chroniques, les spondyloarthrites et les maladies inflammatoires chroniques de l’intestin. Nous avons retrouvé des variations de la composition du microbiote intestinal après traitement par anti-TNFα chez des patients atteints de spondyloarthrite et avons identifié un nœud taxonomique prédictif de la réponse thérapeutique à trois mois. Ce nœud taxonomique, l’ordre des Burkholderiales, étant ainsi un biomarqueur potentiellement utilisable en pratique clinique, nous avons déposé une demande de brevet européen, qui est en cours d’instruction. Ce travail a été poursuivi par un nouveau protocole de recherche clinique incluant des patients atteints de spondyloarthrites mais aussi de maladies inflammatoires chroniques intestinales. Ce protocole est financé par le CHU de Bordeaux dans le cadre de l’Appel d’Offre Interne. Il permettra de valider les hypothèses de notre premier travail, en réalisant notamment des PCR quantitatives utilisant des amorces spécifiques de l’ordre des Burkholderiales. Nous avons de plus retrouvé in vitro pour la première fois à notre connaissance une modulation de la croissance bactérienne chez Bacteroides fragilis en réponse au TNFα humain. / The host/gut microbiota interface is a system of complex interactions whose imbalance is associated with the development of chronic inflammatory diseases. Anti-TNFα treatments are very effective in these diseases, but only in some patients. The purpose of this work was to find a link between the composition of the intestinal microbiota and clinical response to anti-TNFα treatments in two types of chronic inflammatory diseases, spondyloarthritis and inflammatory bowel disease. We found variations in the composition of the intestinal microbiota after treatment with anti-TNFα in patients with spondyloarthritis and identified a taxonomic node predictive of the therapeutic response at 3 months. This taxonomic node, the Burkholderiales order, being a biomarker potentially usable in clinical practice, we have filed a European patent application, which is currently under investigation. This work was continued by a new clinical research protocol including patients with spondyloarthritis but also with inflammatory bowel diseases. This protocol is funded by the Bordeaux University Hospital as part of the internal call for tenders. It will validate the hypotheses of our first work, notably by performing quantitative PCRs using specific primers targeting the order of Burkholderiales. In vitro, we have also found for the first time, to our knowledge, a modulation of bacterial growth in Bacteroides fragilis in response to human TNFα.

Face au vieillissement accru de la population, les maladies neurodégénératives sont désormais un problème de santé publique majeur. Dans plusieurs cas, les dépôts amyloïdes sont constitués de fibres d’IDP (« intrinsically disordered protein »), comme par exemple le peptide Aβ dans les plaques séniles et TAU dans les PHF retrouvés dans la maladie d’Alzheimer, ou encore l’Alpha synucléine dans les corps de Lewy retrouvés dans la maladie de Parkinson. Dans ces maladies, l’accumulation de fibres amyloïdes est au cœur des mécanismes de neurodégénérescence. Ainsi, comprendre les mécanismes biologiques qui mènent à la formation des fibres peut permettre d’envisager de nouveaux traitements et/ou des molécules capables de ralentir ou arrêter la progression de ces pathologies. Ces travaux de thèse vont, dans une première partie, développer les nouvelles méthodologies appliquées à l’étude des IDPs par RMN. Dans une deuxième partie, ils s’attacheront à mieux comprendre les mécanismes d’agrégation de deux IDPs très impliquées dans des maladies neurodégénératives. Le premier cas étudié sera celui de la protéine TAU, impliquée dans la maladie d’Alzheimer, et le deuxième cas sera celui d’Alpha synucléine, impliquée dans la maladie de Parkinson. / Due to population aging, neurodegenerative diseases have become a major public health problem. In many cases, the amyloid deposits are composed of IDP (Intrinsically disordered protein) fibers, as Aß peptide in senile plaques and TAU in the PHF found in Alzheimer's disease, or Alpha synuclein in Lewy bodies found in Parkinson's disease. The accumulation of amyloid fibers is at the heart of the mechanisms of neurodegeneration. The understanding of the biological mechanisms that lead to the formation of the fibers may allow novel treatments and / or molecules that slow or stop the progression of these diseases. Firstly, in this thesis, we will develop new methodologies to study IDPs by NMR. In the second part, we will seek to better understand the mechanisms of aggregation of two IDPs involved in neurodegenerative diseases. The first case will be the aggregation of TAU protein in Alzheimer's disease and the second case will be the aggregation of Alpha synuclein in Parkinson's disease.

ABSTRACT In sub-Saharan Africa a causal relationship has been established between hepatitis B virus (HBV) infection and membranous nephropathy (MN), especially in Black children. The most common method of treatment is interferon therapy, which is however, only effective in 30-40% of patients. The reason for this is unclear. The objective of this pilot study was to determine whether mutations in the complete surface gene of HBV isolated from Black children with HBV-associated MN before, during and after treatment with interferon, had any effect on treatment response and vice versa. HBV DNA was extracted from the serum of a responder, reverter and non-responder patient before, during (4 and 16 weeks) and after (40 weeks) IFN treatment. The preS1/preS2/S region was amplified and cloned, and the clones sequenced. Sequence analyses revealed the preS2 region to be the most variable in the reverter and non-responder and HBsAg was the most variable in the non-responder. Phylogenetic analysis showed that the viral population dynamics between the responder strains and the reverter/non-responder strains differed as a result of various mutations found within the surface gene. Thus the presence of mutations in preS2 and HBsAg of the non-responding patients may carry predictive markers for nonresponse but further investigation would be needed to conclusively prove this.

Zugl.: Giessen, Universiẗat, Diss., 2007.

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Glucagon-like peptide-1 (GLP-1) has received much attention as a novel diabetes therapeutic due to its pleotropic blood glucose-lowering effects, including enhancement of glucose-stimulated insulin secretion, inhibition of gastric emptying and glucagon secretion, and promotion of beta-cell survival and proliferation. GLP-1 is produced in the intestinal L-cell via processing of the proglucagon precursor by prohormone convertase (PC) 1/3. Proglucagon is also expressed in the pancreatic alpha-cell; however, in this tissue PC2 is typically expressed instead of PC1/3, resulting in differential cleavage of proglucagon to yield glucagon as the major product. We hypothesized that expression of PC1/3 in the alpha-cell would induce GLP-1 production in this tissue, and that this intervention would improve islet function and survival. Initial studies in alpha-cell lines demonstrate that adenoviral delivery of PC1/3 to alpha-cells increases GLP-1 production. By encapsulating and transplanting either PC1/3- or PC2-expressing alpha-cells, the following studies show that while PC2-expressing alpha-cells increase fasting blood glucose and impair glucose tolerance, PC1/3-expressing alpha-cells decrease fasting blood glucose and dramatically improve glucose tolerance in normal mice and in mouse models of diabetes. We further show that transplantation of PC1/3-expressing alpha-cells prevents streptozotocin (STZ)- induced hyperglycemia. We also found that PC1/3-expressing alpha-cells also improve cold-induced thermogenesis in db/db mice, demonstrating a previously unappreciated effect of one or more of the PC1/3-derived proglucagon products. Studies in isolated mouse islets demonstrate that adenoviral delivery of PC1/3 to isolated islets increases islet GLP-1 secretion and improves glucose-stimulated insulin secretion and islet survival. Experiments with diabetic mice show that these GLP-1-producing islets are better able to restore normoglycemia in recipient mice following islet transplantation. Taken together, these studies demonstrate that the alpha-cell can be induced to process proglucagon into PC1/3-derived products, and that this shift redirects the alpha-cell from a hyperglycemia-promoting fate to a blood glucose-lowering one. This research opens up avenues for further investigating the therapeutic potential of inducing islet GLP-1 production in isolated human islets and in vivo in diabetes patients, and may represent a novel way to intervene in the progressive loss of beta-cells that characterizes diabetes.

Over the past decade, advances in ethylene oligomerization have witnessed explosive growth of interest from both commercial and academic standpoint, with chromium metal invariably being the metal of preference. A common feature in this literature was the extended long debate regarding the mechanism, metal oxidation states responsible for selectivity and the role of the ligand. This thesis work embarked on the isolation and characterization of new active intermediates called “single component catalysts” (or self activating) to address two important questions: (1) how the catalyst precursors re-arrange upon activation and (2) the real oxidation state of the activated species. Four different ligands systems have been examined for this purpose. The first part is a study on the NPIIIN ligand which can be described as a dynamic and non-spectator ligand. Upon aluminum alkyl activation, a series of single component chromium catalysts for selective ethylene oligomerization and polymerization have been isolated, fully characterized and tested. New selective single component chromium(I) catalysts have also been isolated and tested positively for ethylene trimerization. The second part includes a new series of chromium complexes based on the NPVN ligand. This ligands enabled to obtain the first polymer-free extremely active catalytic system. In both NPN ligand systems, a new activation pathway was discovered by using vinyl Grignard reagent [(CH2=CH)MgCl] as activator and/or reducing agent. The third part explores new modified pyrrole-chromium complexes which were found to be highly active and selective ethylene trimerization catalysts. This part was a continuation of previous work from our lab to complete the mechanistic picture of this highly successful pyrrole-chromium catalyst independently commercialized by Phillips-Chevron and Mitsubishi. Interestingly upon aluminum alkyl treatment, the first example of a Schrock-type chromium ethylidene complex has been isolated and characterized and found to be a potent catalyst for selective ethylene trimerization. Finally, the other ligands introduced in this thesis are new systems called pyridine-SNS and Si-SNS that introduce some modification to the known commercial SNS catalyst (Sasol technology). The introduction of a pyridine ring or a silyl unit in the ligand scaffold has allowed to understand the mechanism of action of this remarkable system.

Over the past decade, advances in ethylene oligomerization have witnessed explosive growth of interest from both commercial and academic standpoint, with chromium metal invariably being the metal of preference. A common feature in this literature was the extended long debate regarding the mechanism, metal oxidation states responsible for selectivity and the role of the ligand. This thesis work embarked on the isolation and characterization of new active intermediates called “single component catalysts” (or self activating) to address two important questions: (1) how the catalyst precursors re-arrange upon activation and (2) the real oxidation state of the activated species. Four different ligands systems have been examined for this purpose. The first part is a study on the NPIIIN ligand which can be described as a dynamic and non-spectator ligand. Upon aluminum alkyl activation, a series of single component chromium catalysts for selective ethylene oligomerization and polymerization have been isolated, fully characterized and tested. New selective single component chromium(I) catalysts have also been isolated and tested positively for ethylene trimerization. The second part includes a new series of chromium complexes based on the NPVN ligand. This ligands enabled to obtain the first polymer-free extremely active catalytic system. In both NPN ligand systems, a new activation pathway was discovered by using vinyl Grignard reagent [(CH2=CH)MgCl] as activator and/or reducing agent. The third part explores new modified pyrrole-chromium complexes which were found to be highly active and selective ethylene trimerization catalysts. This part was a continuation of previous work from our lab to complete the mechanistic picture of this highly successful pyrrole-chromium catalyst independently commercialized by Phillips-Chevron and Mitsubishi. Interestingly upon aluminum alkyl treatment, the first example of a Schrock-type chromium ethylidene complex has been isolated and characterized and found to be a potent catalyst for selective ethylene trimerization. Finally, the other ligands introduced in this thesis are new systems called pyridine-SNS and Si-SNS that introduce some modification to the known commercial SNS catalyst (Sasol technology). The introduction of a pyridine ring or a silyl unit in the ligand scaffold has allowed to understand the mechanism of action of this remarkable system.

Hedge funds are private investment funds characterized by unconventional strategies. This thesis employed multi-factor CAPM to evaluate the performance, or manager skill of hedge funds investment segments by using CSFB/Tremont Hedge Fund Indices from January 1994 to September 2005. The performance evaluation is based on the concept of ¡°Jansen¡¯s alpha¡±, which is estimated by applying Generalized Method of Moment. The finding is that hedge funds industry in general displayed the ability to outperform market proxy. Global Macro shows the strongest manager skill, followed by Event Driven, Equity Market Neutral and Long/Short Equity. This thesis also investigates the consistency of hedge funds performance over market environment. It was discovered that the hedge funds industry in general and all the sub-category investment segments except Convertibly Arbitrage, Emerging Market and Fix income Arbitrage displayed the ability to cushion the impact of financial shocks.