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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.
1

The role of lipoteichoic acid in the adhesion of oral streptococci

Manning, J. E. January 1988 (has links)
No description available.
2

Optimalizace imunoterapie melanomu založené na kotvení laminarinu na povrch nádorových buněk / Optimization of melanoma immunotherapy based on the anchoring of laminarin on the surface of tumor cells

ŠVECOVÁ, Ivana January 2013 (has links)
The aim of this thesis was to find optimal anticancer regimen of therapy, based on a naturally occuring polysaccharide laminarin. It was studied on the Mus musculus skin melanoma B16-F10. There were explored an ajuvant effect of LTA. Mixture of laminarin with LPS was applied with various anchorings and was tryed out the possible replacement of LPS. Using the flow cytometry there were determined progress of immune cells during application. This therapy resulted in reduction of tumor volume and the prolongation of overall survival.
3

Aplicação da citometria de fluxo no diagnóstico da leishmaniose tegumentar americana

Pereira de Oliveira, Andresa 31 January 2011 (has links)
Made available in DSpace on 2014-06-12T23:13:15Z (GMT). No. of bitstreams: 2 arquivo2928_1.pdf: 1648084 bytes, checksum: 945302eb189a3a710e3e0e8bcbdfc641 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2011 / Faculdade de Amparo à Ciência e Tecnologia do Estado de Pernambuco / A LTA é uma infecção parasitária tendo Leishmania (Viannia) braziliensis) como agente etiológico de maior incidência no Brasil. Em todas as formas clínicas da doença, sabe-se que a resposta imune é dependente de células T. Embora estudos avaliem a resposta humoral na LTA, ainda não está esclarecido o papel de anticorpos específicos na imunidade contra Leishmania. Além disso, o diagnóstico da LTA demonstra dificuldades pois o mesmo é realizado por associações clínicas, epidemiológicas e laboratoriais. Considerando os benefícios da citometria de fluxo, uma nova abordagem utilizada na pesquisa de anticorpos com aplicabilidade superior aos diferentes protocolos de detecção e revelação convencionais, este estudo trouxe uma alternativa através da pesquisa de anticorpos IgG de L(V)braziliensis, aplicável ao diagnóstico da LTA e critério de cura.O objetivo deste estudo foi comparar as técnicas de reação de imunofluorescência indireta (IFI) e citometria de fluxo na avaliação clínica-laboratorial dos pacientes antes e após cura clínica e avaliar a aplicabilidade da citometria de fluxo no monitoramento pós-terapêutico dos pacientes. Soros de 14 pacientes antes do tratamento (AT), 13 pacientes 1 ano após tratamento (PT), 10 pacientes 2 e 5 anos PT foram analisados e os resultados foram expressos em níveis de reatividade de IgG, a partir da porcentagem de parasitos fluorescentes positivos (PPFP). A diluição 1:256 das amostras permitiu diferenciar os indivíduos AT e PT. A análise comparativa da IFI e da citometria de fluxo pela curva ROC (Receiver Operating Characteristic Curve) demonstrou, respectivamente, ASC (área sob a curva) =0,78 (IC95%= 0,64-0,89) e ASC=0,90 (IC95%= 0,75-0.95), demonstrando elevada acurácia do teste de citometria de fluxo. Nossos dados demonstram que 20% foi o melhor ponto de corte identificado pela curva ROC para o ensaio de citometria de fluxo. Este ensaio apresentou sensibilidade de 86% e especificidade de 77%, enquanto a IFI apresentou sensibilidade de 71% e especificidade de 69%. O monitoramento pós terapêutico através da análise comparativa dos índices de desempenho das técnicas em 1, 2 e 5 anos PT, revelou melhor desempenho da citometria de fuxo em relação a IFI. Portanto, a citometria de fluxo demonstrou ser uma alternativa diagnóstica aplicada ao estudo da LTA e que as informações obtidas nesse estudo abrem perspectivas para o monitoramento de cura pós- terapêutica da LTA
4

Un nouveau défaut héréditaire chez l’homme : déficit en TIRAP

Israel, Laura 21 November 2013 (has links)
Les maladies infectieuses constituent le principal groupe de maladies humaines communément considérées comme étant d’origine environnementale. Cependant, une question fondamentale dans ce domaine est la variabilité interindividuelle : pourquoi, au sein d’une même population exposée aux mêmes pathogènes, seule une minorité des individus infectés par un pathogène donné va développer une maladie dont l’expression clinique peut varier de l’état asymptomatique à la mort pour les formes les plus sévères. Le microbe est donc nécessaire mais non suffisant pour expliquer ces divergences. Selon la théorie génétique des maladies infectieuses, une proportion d’enfants ayant une ou plusieurs infections sévères mais étant par ailleurs sains, présenterait une immunodéficience primaire Mendélienne à l’origine d’une réponse immunitaire altérée spécifique du pathogène responsable. En considérant la susceptibilité accrue à des infections sévères par des bactéries pyogènes, cette hypothèse a conduit à la découverte, dans les années 2000, de plusieurs immunodéficiences primaires dans la voie de signalisation NF-kB, avec des mutations dans les gènes NEMO/IKBKG, IKBA, IRAK4 et MyD88 chez des enfants présentant des infections sévères par bactéries pyogènes, notamment Streptococcus pneumoniae et Staphylococcus aureus, et conduisant à une altération des voies Toll-interleukine-1 récepteur (TIR)-NF-kB. Mon travail de thèse a principalement porté sur l’étude d’une patiente aujourd’hui âgée de 5 ans. Elle est issue d’une famille consanguine et a souffert d’une pneumonie sévère à l’âge de 3 mois à la suite d’une infection par une souche PVL+ de S. aureus. .J’ai identifié chez elle un défaut autosomique récessif complet en TIRAP. Cependant, sept autres membres de la famille âgés entre 16 et 50 ans sont homozygotes pour la même mutation et n’ont jamais souffert d’infection sévère. TIRAP est un adaptateur des récepteurs TLR2 et TLR4 et la mutation rare R121W affecte un acide aminé très conservé dans son domaine TIR. L’allèle mutant de TIRAP induit une expression normale de l’ARN messager ainsi que de la protéine mais demeure non fonctionnel. Les réponses après stimulation par différents agonistes du TLR2 tels que le PAM2CSK4, le PAM3CSK4, et le FSL-1 ainsi que par le LPS, agoniste du TLR4 sont altérées dans les fibroblastes, les granulocytes et les monocytes des individus homozygotes pour la mutation R121W. Cependant, la réponse des cellules sanguines totales à l’acide lipoteichoïque (LTA) purifié de S. aureus, un autre agoniste du TLR2 est altérée uniquement chez la patiente. J’ai pu montrer que ce défaut est dû à une absence d’anticorps dirigés contre le LTA dans le plasma de la patiente. L’effet combiné de la mutation du gène TIRAP et de l’absence d’anticorps anti-LTA pourrait expliquer la survenue de l’infection sévère par S. aureus chez le cas index. L’ensemble de ce travail décrit pour la première fois un défaut héréditaire en TIRAP chez l’homme et fournit ainsi une meilleure compréhension du rôle de cette protéine dans les réponses en aval des TLRs. Il suggère également que, chez l’homme, la voie dépendante de TIRAP en aval du TLR2 est importante pour le contrôle des infections par S. aureus, au moins chez les enfants présentant un défaut de production d’anticorps anti-LTA ; cependant, TIRAP serait un gène en partie redondant dans l’immunité antibactérienne. / We describe a kindred comprising eight individuals with autosomal recessive complete deficiency of TIRAP (also called MAL), an adaptor downstream of TLR2 and TLR4. The 4-year-old proband suffered at three month of age from a life-threatening pneumonia caused by Staphylococcus aureus. Seven adult relatives, aged between 16 and 50 years, homozygous for the same TIRAP mutation never suffered from any serious infections. The rare missense R121W mutation affects a highly conserved amino acid in the TIR domain of TIRAP. The mutant TIRAP allele is expressed but displays loss of function. Responses to a variety of TLR2 agonists, including PAM2CSK4, PAM3CSK4, and FSL-1, and to the TLR4 agonist lipopolysaccharide (LPS), were impaired in fibroblasts, granulocytes, and monocytes of all TIRAP R121W homozygous individuals tested. Interestingly, the whole blood response to staphylococcal lipoteichoic acid (LTA), another TLR2 agonist, was impaired only in the index case. This defective response was due to a lack of anti-LTA antibodies in the patient’s plasma. The combined effect of the TIRAP R121W mutation and the absence of anti-LTA antibody provide an explanation for severe staphylococcal disease in the index case. These results provide the first description of human inherited TIRAP deficiency and help to delineate the role of human TIRAP in TLR responses. They suggest that human TIRAP-dependent TLR2 immunity is important for the control of S. aureus infection, at least in children lacking anti-LTA antibodies, but that TIRAP is otherwise redundant in host defense.
5

Continuous Zeolite Crystallization in Micro-Batch Segmented Flow

Vicens, Jim 25 April 2018 (has links)
Zeolites are porous aluminosilicates that occur both naturally and synthetically, having numerous applications in catalysis, adsorption and separations. Despite over a half century of characterization and synthetic optimization of hundreds of frameworks, the exact mechanism of synthesis remains highly contested, with crystallization typically occurring under transport-limited regimes. In this work, a microcrystallization reactor working under segmented oscillatory flow has been designed to produce a semi-continuous flow of zeolite A. The fast injection of the reactants in a mixing section forms droplets of aqueous precursors in a stream of paraffin, dispersing microdroplets and avoiding any clog from occurring in the system. The crystallization occurred in the system at atmospheric pressure and isothermal conditions (65ºC). This allowed for a rather slow crystallization kinetics which was important to study and highlight the different crystallization mechanisms between flow and batch synthesis. The morphology, size distributions, crystallinity, and porosity were examined by ex-situ characterization of the samples by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and N2 Physisorption to support the conclusions drawn. The size distribution of the particles achieved in the flow reactor was conclusively narrower than the distribution achieved in the batch reactor. The average size of the crystals for both synthesis methods is reported as 400 nm and the crystallinity achieved was comparable between the two. However, the morphology was quite different between the two systems, the flow products having a much higher mesoporosity due to the presence of crystal aggregates at high crystallinity when compared to the batch crystals. Finally, extended crystallization times leads to a decline of the crystallinity of the product, which might be explained by the metastable state of zeolites in solution.
6

Continuous Zeolite Crystallization in Micro-Batch Segmented Flow

Vicens, Jim 25 April 2018 (has links)
Zeolites are porous aluminosilicates that occur both naturally and synthetically, having numerous applications in catalysis, adsorption and separations. Despite over a half century of characterization and synthetic optimization of hundreds of frameworks, the exact mechanism of synthesis remains highly contested, with crystallization typically occurring under transport-limited regimes. In this work, a microcrystallization reactor working under segmented oscillatory flow has been designed to produce a semi-continuous flow of zeolite A. The fast injection of the reactants in a mixing section forms droplets of aqueous precursors in a stream of paraffin, dispersing microdroplets and avoiding any clog from occurring in the system. The crystallization occurred in the system at atmospheric pressure and isothermal conditions (65ºC). This allowed for a rather slow crystallization kinetics which was important to study and highlight the different crystallization mechanisms between flow and batch synthesis. The morphology, size distributions, crystallinity, and porosity were examined by ex-situ characterization of the samples by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and N2 Physisorption to support the conclusions drawn. The size distribution of the particles achieved in the flow reactor was conclusively narrower than the distribution achieved in the batch reactor. The average size of the crystals for both synthesis methods is reported as 400 nm and the crystallinity achieved was comparable between the two. However, the morphology was quite different between the two systems, the flow products having a much higher mesoporosity due to the presence of crystal aggregates at high crystallinity when compared to the batch crystals. Finally, extended crystallization times leads to a decline of the crystallinity of the product, which might be explained by the metastable state of zeolites in solution.
7

NMR Structural Studies of Endotoxin Receptor CD14 in Complex with Gram-Negative and Gram-Positive Endotoxin

Albright, Seth Andrew 01 August 2011 (has links)
Endotoxin recognition by the innate immune receptor CD14 is a critical part of the innate immune system’s early detection and activation of the inflammatory response during microbial invasion. The differential recognition and high affinity binding of endotoxins from gram-negative and gram-positive bacteria is performed by the innate immune receptor CD14. Upon endotoxin binding, CD14 transfers the specific endotoxins to a Toll-like receptor signaling complex, which is responsible for initiating the intracellular signaling cascade. In the presence of overwhelming infection, the effects of CD14 lead to the over-activation of the inflammatory response, which results in the life threatening condition known as sepsis. Preparation of a 15N isotopically labeled truncated version of soluble CD14, using Pichia pastoris, allowed direct structural observation of the binding interaction between CD14 and two endotoxin ligands, lipopolysaccharide (LPS) and lipoteichoic acid (LTA), from gram-negative and gram-positive bacteria, respectively using solution NMR spectroscopy. These studies revealed that CD14 uses both a common set of residues, and endotoxin specific subsets of residues, to bind LPS and LTA. To further investigate the structural features of each endotoxin recognized by CD14, 13C 15N isotopically labeled Kdo2–Lipid A, a fully active chemically defined gram-negative endotoxin, and LTA lipid anchor, the minimal unit of LTA, were produced. This allowed detailed NMR spectral mapping of these agonist ligands bound to sCD14 which identified, for the first time, structural regions and features in each that are strongly affected during complex formation with sCD14. Additionally, the presence of differential dynamic behavior was seen in both CD14 and the ligands upon complexation. This behavior suggests a likely role for dynamics in the mechanism of pattern recognition by CD14, which uses the dynamic ability of specific residue combinations to differentially affect endotoxin binding. Using NMR, the dynamic behavior of CD14 was further investigated using temperature and pH-dependence studies of isotopically labeled CD14. These studies clearly demonstrated the presence of multiple conformations for several residues, and may provide a possible explanation for the broad specificity of ligand binding by CD14. In addition, the spin-labeling of isotopically labeled lipid A enabled the collection of intermolecular distances on CD14 bound lipid A.
8

LTA kontra självfall : Ett långsiktigt perspektiv / Pressure sewage systems : A long term perspective

Holmberg, Mattias, Hen, Stefan January 2013 (has links)
Detta arbete syftar till att göra en utvärdering av hur de två skilda spillvattensystemen LTA (Lätt TryckAvlopp) och konventionellt självfallsavlopp står sig mot varandra ur ett långtidsperspektiv. Aspekter så som investering, drift, underhåll, miljöpåverkan, teknik och anläggning har analyserats och sammanställs av denna rapport, samt ett program som beräknar den ekonomiska aspekten mellan respektive system. Programmet, där användaren ges möjligheten att specificera sitt eget område, ger en fingervisning om den lösning som ur ekonomisk aspekt är mest fördelaktig. Detta kombinerat med den kunskap som samlats i rapporten ska leda till ett mer medvetet val hos kommuner och andra VA-huvudmän i Sverige. / The purpose of this report is to make a comparison between the two currently used sewage solutions, PSS (Pressure Sewage System) and the more conventional gravity based sewage-system during a vast period of time. Aspects such as investment, maintenance, upkeep, environmental, technology and terrain have been analyzed. The research has resulted in this report and an Excel-program which calculates an estimated economical difference between the two solutions, in a specific case chosen by the user, to determine which is more economically beneficial. This program, used hand in hand with the report, is suppose to increase the knowledgebase regarding the subject of sewage solutions among officials working with these kinds of matters in Sweden.
9

The susceptibility of primordial germ cells to malignant transformation and isolation and characterization of members of a new gene family differentially expressed in invasive and non-invasive immortalized male germ cells / Die Potenz der Primordialen Keimzellen zur malignen Transformation und Isolierung und Charakterisierung von Mitgliedern einer neuen Genfamilie, die in invasiven immortalisierten Keimzellen überexprimiert sind

Ahmed, Manal Bayomi Mahmoud 29 January 2002 (has links)
No description available.
10

Differential Effects of Gram-positive and Gram-negative Inflammatory Stimuli on the Expression and Function of Energy Substrate Transporters in Human Mammary Epithelial cells

2012 August 1900 (has links)
Mastitis is often bacterial in origin. Lipoteichoic acid (LTA) and lipopolysaccharide (LPS), endotoxins from gram-positive and gram-negative bacteria, respectively, are potent inducers of mammary gland inflammation. Inflammation can alter expression of transporters responsible for transport of substrates important in synthesis of milk constituents and cellular metabolic energy. Since, gram-positive and gram-negative bacterial infections cause a different clinical course of mastitis, I investigated whether LTA and LPS differentially alter proton-coupled (MCT1) and sodium-coupled monocarboxylate transporter (SMCT1, SMCT2) expression and functional outcomes of altered expression. Human mammary epithelial cells (MCF-12A) were incubated with 1 microgram/mL LPS or LTA for 6, 12 and 24 hours and mRNA expression of TNF-alpha, IL-1β, IL-6, MCT1, SMCT1, and SMCT2 were measured using Quantitative RT-PCR. LPS decreased SMCT1, but increased SMCT2 expression after 6 h, while LTA increased MCT1 expression at 6 h, followed by gradual decrease in expression until 24 h. To know whether such differential changes in transporter expression by LPS and LTA could cause changes in cellular energy production, I quantified creatine (Cr) and high-energy phosphate substrates (CrP, ATP, ADP, AMP) and oxygen consumption rates using HPLC and Hansatech oxygen electrode, respectively. At 12 h, LPS increased concentrations of Cr, CrP, ATP and ADP, whereas LTA caused changes in CrP and ADP concentrations relative to control. Both LPS and LTA decreased oxygen consumption rates after 12 h. Furthermore, to know whether changes in transporter expression lead to differences in substrate availability, I performed uptake studies for carnitine using radiolabelled tritium L-carnitine. LPS and LTA challenge did not affect the affinity, but caused a 2-3-fold increase in maximal activity (Vmax) of carnitine transport. Although increases in Vmax were not significant, the increase in Vmax after 12 h exposure by LPS and LTA corresponds to changes in mRNA expression of the OCTN2 transporter (previously reported in the laboratory). In conclusion, LPS and LTA differentially alter mRNA expression of transporters, which leads to changes in cellular energy levels and oxygen consumption rates and possibly to changes in the functional activity of transporters. Whether such differences contribute to the different clinical course of mastitis warrants further investigation.

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