Thesis (Ph. D.)--McMaster University (Canada), 1990. / Source: Dissertation Abstracts International, Volume: 52-10, Section: B, page: 5258. Supervisor: O.E. Hileman, Jr.

Diss. (sammanfattning) Göteborg : Univ., 2007. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 132-142).

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 131-132). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 131-132). Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2005. / "December 2005" The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Vita. Includes bibliographical references.

Made available in DSpace on 2014-10-09T12:46:32Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:07Z (GMT). No. of bitstreams: 1 08286.pdf: 4148498 bytes, checksum: f9d73111bc4c47c409ba95ffcaec8d14 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP / FAPESP:99/06632-0

Les héparane sulfate protéoglycanes (HSPG) sont, comme l’ensemble des protéoglycanes (PG), constitués d’une partie protéique et d’un glycosaminoglycane (GAG), en l’occurrence l’héparane sulfate (HS) pour les HSPG. Ils font partie intégrante de la matrice extracellulaire (MEC). Les PG sont capables, par leurs GAG, de lier un certain nombre de partenaires tels que les facteurs de croissance, chemokines, cytokines ou enzymes. Ils régissent donc la biodisponibilité de nombreux médiateurs solubles et par conséquent leur activité biologique. Ils sont ainsi impliqués dans la régulation de nombreux processus tels que la prolifération, la différenciation, le remodelage tissulaire, l’angiogenèse... De plus, il a été démontré que la liaison de protéines possédant un site heparan binding (HB) avec l’HS des HSPG les protégent de la dégradation enzymatique. Cependant, les HSPG sont parmi les premiers composants de la MEC à être digérés par les héparanases cellulaires lors d’agressions tissulaires. Cette digestion rend les sites HB disponibles et les protéines sensibles à la dégradation protéolytique. C’est donc dans le but de protéger les HSBP (heparan sulfate binding protein) qu’a été développée la technologie des héparanes mimétiques (HM) qui vont se substituer aux HS dégradés sur les sites HB disponibles et protéger les protéines du milieu lésé. Ces HM, déjà utilisés comme agent thérapeutique de la MEC, sont désignés, dans cette utilisation, sous le sigle RGTA pour regenerating agent puisqu’ils augmentent la vitesse et la qualité de la réparation tissulaire, pouvant conduire à une véritable régénération des tissus. Lors du développement tumoral et métastatique, il a été démontré que l’activité enzymatique des héparanases est démultipliée, responsable d’une dégradation accrue des HS. Dans ce contexte, les HM vont pouvoir se fixer sur cette matrice lésée d’où l’idée de leur utilisation diagnostique en cancérologie. L’utilisation d’HM marqué (HM*) par un radioisotope tel que le fluor 18 (18F) et suivi par imagerie moléculaire TEP-Scan (tomographie par émission de positons associée au scanner) devrait permettre un marquage particulièrement efficace des matrices environnant les cellules tumorales et métastasées. Les HM* pourraient, en effet, cibler la MEC impliquée, par sa dégradation précoce, dans les processus de croissance et de dissémination tumorale et devenir un nouveau marqueur oncologique en imagerie moléculaire. A ce jour, parmi les différents marqueurs oncologiques étudiés, aucun ne s’adresse au compartiment matriciel. L’usage des HM* devrait ainsi permettre la détection des zones péri-tumorales et trouver une place dans le diagnostic précoce du cancer et son suivi thérapeutique. / Heparan sulfate proteoglycans (HSPG), like all proteoglycans (PG), consisting of a protein portion and a glycosaminoglycan (GAG), heparan sulphate (HS) for HSPG. They are part of the extracellular matrix (ECM). PG are able, through their GAG, to bind a number of partners such as growth factors, chemokines, cytokines or enzymes. They regulate the bioavailability of many soluble mediators and thus their biological activity. They are thus involved in the regulation of many processes such as proliferation, differentiation, tissue remodeling, angiogenesis... In addition, it was shown that the binding of proteins having a heparan binding site (HB) with HS of HSPG protect them from enzymatic degradation. However, HSPG are among the first components of the ECM to be digested by heparanase during cellular tissue damage. This digestion makes HB sites available and proteins are sensitive to proteolytic degradation. It is in order to protect the HSBP (heparan sulfate binding protein) that was developed technology heparan mimetics (HM) that will replace the degraded HS on available HB sites and protect proteins of middle injured. These HM, already used as a therapeutic agent of the ECM, are identified in this use under the symbol RGTA for regenerating agent because they increase the speed and quality of the tissue repair, potentially leading to a true tissue regeneration. During tumor development and metastasis, it has been shown that the enzymatic activity of heparanase is multiplied, leading to an increased degradation of HS. In this context, the HM will be able to fix this matrix injured hence the idea of their diagnostic use in oncology. Using labeled HM (HM*) with a radioisotope such as fluorine-18 (18F) and followed by molecular imaging PETScan (positon emission tomography with scanner associated) should allow a particularly efficient marking of the matrix surrounding metastatic and tumor cells. HM* could indeed target ECM involved, through its early degradation in the processes of tumor growth and tumor spread and become a new marker oncology in molecular imaging. To date, among the various studied cancer markers, none address the matrix compartment. The use of HM* should allow the detection of peri-tumor and find a place in the early diagnosis of cancer and the therapeutic monitoring.

L'interferon-γ (IFNγ) est une cytokine immunomodulatrice puissante, également dotée d'une activité antivirale. Il possède deux ligands de haute affinité : un récepteur par lequel il transmet ses signaux et des polysaccharides complexes de la famille des héparanes sulfates (HS), tous deux situés à la surface cellulaire. In vivo, la liaison aux HS permet de concentrer localement la cytokine et de réguler son activité biologique par le biais d'une protection partielle du domaine C-terminal de la protéine. Ce domaine C-terminal, caractérisé par deux domaines basiques D1 et D2, est impliqué dans la reconnaissance du récepteur et des HS. Dans ce contexte, nos travaux se sont attachés à définir les aspects structuraux de l'interaction de l'IFNg, et plus précisément de son extrémité C-terminale, avec ses deux ligands. Pour cela, de divers mutants ponctuels, multiples et de délétion de l'IFNg ont été produites, purifiées et étudiées. Leur capacité à lier les HS et le récepteur de l'IFNg est déterminée par SPR puis leur influence sur l'activité antivirale de l'IFNg est déterminée. Les paramètres thermodynamiques de l'interaction IFNg:HS-oligosaccharides sont investigués. Par ailleurs, nous avons préparé une banque oligosaccharidique dérivée d'HS. Le criblage de cette banque, pour sa capacité à lier l'IFNγ, a permis de démontrer que l'IFNg reconnaissait des motifs de sulfatation particuliers. Finalement, nous avons tenté de cristallisé le complexe IFNg:HS-oligosaccharide, jusqu'à présent sans obtention de cristaux qui diffractent. Ces différentes approches visent à élucider le mécanisme de reconnaissance d'IFNg par des HS. Ceci afin de concevoir un mime de ce site d'interaction inhibant la signalisation de l'IFNg. Enfin, une compréhension plus détaillé de l'interaction de l'IFNg avec les HS et son récepteur reste à établir afin d'entièrement comprendre comment l'IFNg migre des HS vers l'IFNgR. / Interferon-γ (IFNγ) is a strong immunomodulating cytokine with some antiviral activity. It has two ligands for which it has high affinities: a receptor through which it transmits its signals, and complex polysaccharides of the heparan sulphate (HS) family. Both are situated on the cellular surface. In vivo, binding on the HS permits local concentration of the cytokine, and regulates its biological activity via a partial protection of the C-terminal region. This C-terminal region, characterised by two basic domains, D1 and D2, is implicated in the recognition of the receptor and the HS. In this context, we investigated the structural features for the interaction of IFNγ, and more specifically the importance of his C-terminus, with both of his cellular ligands. Therefore, we produced, purified and examined various mutants of IFNγ, including points, multiples and deletions mutants. There ability to bind to HS and the IFNγ receptor is examined by SPR and there influence on IFNγ's antiviral activity is determined. The thermodynamics complexation of IFNγ with the HS-oligosaccharides is examined. Moreover, we have prepared an oligosaccharidic library derived from HS. By screening this library for its capacity to bind IFNγ, we have demonstrated that the cytokine recognizes a particular sulphated pattern. Finely, we tried to crystallize the IFNγ:HS-oligosaccharide complex, without obtaining diffracting crystals yet. These studies contribute to clarify the mechanism of recognition of IFNγ by the HS. This would enable us to design a mimic of the interaction site for IFNγ on the HS, who inhibits inappropriate signaling of the cytokine. Finely, a detailed comprehension of the interaction of IFNγ with his receptor and with the HS needs to be established to fully understand how IFNγ migrates for the HS to its receptor.

A falta de estudos de caráter científico sobre os fatores intervenientes para desencadear e/ou acelerar o processo de alteração dos sulfetos, denominado oxidação, bem como a influência do tipo de aglomerante hidráulico no desenvolvimento das manifestações patológicas no concreto, decorrentes do emprego de agregado contendo esse mineral em sua composição, motivou o desenvolvido desta tese. Neste sentido, o presente trabalho investiga a influência de cinco tipos de aglomerantes na durabilidade de concretos, quando em sua composição agregados com diferentes teores de sulfetos são empregados. Assim, o programa experimental da pesquisa foi dividido em duas etapas, denominadas Etapa 1 e Etapa 2. Nos concretos preparados para a Etapa 1, utilizou-se agregado quartzo-muscovita-xisto contendo 3,89% de sulfetos e três tipos de aglomerantes, sendo um de referência (CP II-F-32) e os outros dois resultantes da substituição parcial desse aglomerante por 40% e 60% de escória de alto-forno moída. Na Etapa 2, o mesmo tipo de agregado com 0,56% de sulfetos foi empregado, sendo utilizados também três tipos de aglomerantes, a saber, CP II-F-32, CP III-40-RS e CP IV-32. O principal objetivo foi avaliar o desempenho dos concretos confeccionados com esses aglomerantes frente ao ataque interno por sulfatos, fenômeno este resultante do processo de oxidação dos sulfetos em ambiente com umidade elevada por até aproximadamente cinco anos. Deste estudo, procedeu-se inicialmente uma investigação completa, incluindo em nível microestrutural, dos agregados contendo sulfetos "in natura", ou seja, antes de serem utilizados como material nos concretos. Em seguida, realizou-se uma avaliação comparativa do desempenho dos concretos, tendo-se como base análises microestruturais e cristalográficas, por meio da microscopia ótica, microscopia eletrônica de varredura, difração de raios X e análise termogravimétrica, algumas realizadas nos agregados e outras nas argamassas extraídas dos concretos. O comportamento dos concretos frente à resistência, à compressão e ao módulo de elasticidade foi avaliado até os três anos de idade. Ensaios de expansão e as investigações visuais nas superfícies externas dos concretos foram realizados por aproximadamente cinco anos. Os resultados mostraram que a pirrotita é o sulfeto mais reativo do sistema, principal mineral responsável pelas alterações observadas nos agregados extraídos dos concretos. As alterações foram diagnosticadas tanto nos agregados estocados no tempo quanto naqueles utilizados como material na composição dos concretos. Evidenciou-se que o processo de oxidação desencadeia o surgimento de manifestações patológicas ao longo do tempo que afetam as características dos concretos, promovem a expansão desse material, além de interferir em suas propriedades elastomecânicas. Tais efeitos foram resultantes da formação de produtos deletérios decorrentes do próprio processo de oxidação, como também das reações químicas entre os íons agressivos liberados durante este fenômeno e os compostos da pasta de cimento. Os aglomerantes investigados apresentaram comportamentos distintos frente ao ataque por sulfetos. Constatou-se também que quanto maior a concentração de sulfetos, especificamente de pirrotita, mais intensos e expressivos são os níveis de deterioração observados nos concretos investigados ao longo do tempo. Por fim, verifica-se que o ambiente com elevada umidade foi um parâmetro fundamental para acelerar o processo de oxidação destes minerais contidos nos agregados empregados nos concretos. / The strong motivation to the development of this thesis was the lack of scientific studies explaining the intervening factors that give rise to and/or accelerate the alteration (oxidation) of sulfides and the influence of the type of hydraulic cement on the development of pathological manifestations in concrete that have used aggregate with sulfide minerals. Therefore, this study investigates the influence of five types of cements on the durability of concrete when aggregates with different contents of sulfides are used. Thus, the experimental program of the research study was separated into two stages, designated Stage 1 and Stage 2. In the concretes prepared for Stage 1, a quartz-muscovite-schist aggregate containing 3.9% of sulfides and three types of cement were used. One type of cement was for reference (CP II-F- 32) and the other two resulting from the partial replacement of this cement by 40% and 60% of ground blast furnace slag. In Stage 2, the same type of aggregate with 0.6% of sulfides was used with three types of cements, specifically CP II-F-32, CP III-40-RS and CP IV-32. The main purpose was to assess the performance of the concretes prepared with these cements due to internal sulfate attacks resulting from the process of sulfide oxidation of aggregate in a high moisture environment up to approximately five years. Based on this study, a complete investigation was conducted including an approach at a microstructural level of the aggregates containing sulfides itself before have been used to cast concretes. Then, a comparative assessment of the performance of the concretes was carried out using microstructural and crystallographic investigation by means of optical microscopy, scanning electron microscopy, X-ray diffraction and thermogravimetric analyses. In order to understand the behavior of the assayed concretes, their compressive strength and modulus of elasticity were evaluated during three years. Expansion tests and visual observations of the external surfaces of the concretes were also carried out for approximately five years. The results showed that pyrrhotite is the most reactive sulfide in the system, the main mineral responsible for the changes observed in the aggregates extracted from the concretes. The changes were diagnosed in the aggregates stored over time as well as in those employed as aggregates of the concretes. It was found that the oxidation process gives rise to the emergence of pathological events over time which affects the characteristics of concrete, promotes the expansion of this material, besides interfering in its elastic-mechanical properties. These effects resulted from the formation of deleterious products arising from the oxidation process itself and also from the chemical reactions between the aggressive ions released during this phenomenon and the compounds of the hydrated cement pastes. The investigated cements showed different behaviors with respect to sulfide attack. It was also verified that the higher the concentration of sulfides, specifically pyrrhotite, the more intense and expressive are the observed levels of deterioration in the investigated concretes over time. Lastly, it was evidenced that a high-moisture environment was an essential parameter to accelerate the oxidation process of these minerals contained in the aggregates used in the concretes.