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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

Properdin Binds Pseudomnas aeruginosa and is Required for Neutrophil Extracellular Trap Mediated Activation of Complement Alternative Pathway

Yuen, Joshua 11 December 2013 (has links)
Neutrophils play an important, yet poorly understood role, in complement mediated pathologies. Here we identified that neutrophils contain key components from the complement alternative pathway: properdin (CFP), complement component 3 (C3), complement factor B (CFB), and complement factor H (CFH). Activation of neutrophils resulted in secretion of these complement components. When neutrophils are further activated to form neutrophil extracellular traps (NETs), CFP is deposited onto the surfaces of the NETs. In addition, CFP is able to bind to Pseudomonas aeruginosa, an opportunistic bacterium which can activate neutrophils to form NETs. Furthermore, NETs activate complement and increase formation of the terminal complement complex. The activation of complement on NETs can be initiated through multiple pathways, however, activation of the alternative pathway is dependent on CFP. This mechanism, potentially required for effective host defense, may also contribute to complement activation and disease.
2

Properdin Binds Pseudomnas aeruginosa and is Required for Neutrophil Extracellular Trap Mediated Activation of Complement Alternative Pathway

Yuen, Joshua 11 December 2013 (has links)
Neutrophils play an important, yet poorly understood role, in complement mediated pathologies. Here we identified that neutrophils contain key components from the complement alternative pathway: properdin (CFP), complement component 3 (C3), complement factor B (CFB), and complement factor H (CFH). Activation of neutrophils resulted in secretion of these complement components. When neutrophils are further activated to form neutrophil extracellular traps (NETs), CFP is deposited onto the surfaces of the NETs. In addition, CFP is able to bind to Pseudomonas aeruginosa, an opportunistic bacterium which can activate neutrophils to form NETs. Furthermore, NETs activate complement and increase formation of the terminal complement complex. The activation of complement on NETs can be initiated through multiple pathways, however, activation of the alternative pathway is dependent on CFP. This mechanism, potentially required for effective host defense, may also contribute to complement activation and disease.
3

Vapor Intrusion at a Site with an Alternative Pathway and a Fluctuating Groundwater Table

January 2015 (has links)
abstract: Vapor intrusion (VI), can pose health risks to building occupants. Assessment and mitigation at VI impacted sites have been guided by a site conceptual model (SCM) in which vapors originate from subsurface sources, diffuse through soil matrix and enter into a building by gas flow across foundation cracks. Alternative VI pathways and groundwater table fluctuations are not often considered. Alternative VI pathways, involving vapor transport along sewer lines and other subsurface infrastructure, have recently been found to be significant contributors to VI impacts at some sites. This study evaluated approaches for identifying and characterizing the significance of alternative VI pathways and assessed the effectiveness of conventional mitigation at a site with an alternative VI pathway that can be manipulated to be on or off. The alternative pathway could not be identified using conventional pathway assessment procedures and can only be discovered under controlled pressure method (CPM) conditions. Measured emission rates were two orders of magnitude greater than screening model estimates and sub-foundation vertical soil gas profiles changed and were no longer consistent with the conventional VI conceptual model when the CPM test was conducted. The pipe flow VI pathway reduced the vacuum performance of the sub-slab depressurization (SSD) VI mitigation system, but the SSD system still provided sufficient protection to the house. The relationship between groundwater table fluctuations and subsurface vapor emissions and transport is examined using multi-year data from the field site, and is studied in the laboratory. In addition, a broader range of conditions is examined through use of modeling validated with the experimental data. The results indicate that fluctuating groundwater tables will lead to amplified volatile organic chemical (VOC) emissions from groundwater to soil surface relative to steady water table elevation, however, the magnitude of this amplification is less concerned when long-term water fluctuation present. No clear correlations were found between VOC emissions and water table changes at the study site where annual water table fluctuations of about 0.3 m existed. Significant VOC emission amplifications by water table fluctuation would be expected under shallow groundwater conditions according to model analysis results. / Dissertation/Thesis / Doctoral Dissertation Civil and Environmental Engineering 2015
4

The role of the alternative pathway of the complement system in the development of dense deposit disease

Abeleda, Maria Asuncion Abrera 01 July 2010 (has links)
Dense Deposit Disease (DDD) causes chronic renal dysfunction which progresses to end-stage renal disease in about half of patients within 10 years of diagnosis. Deficiency of and mutations in complement Factor H (CFH) are associated with the development of DDD, suggesting that dysregulation of the alternative pathway (AP) of the complement cascade is important in disease pathophysiology. Patients with DDD are studied to determine whether specific allele variants of the genes of the alternative pathway of the complement system segregate preferentially with the DDD. We have screened coding and intronic regions of genes of the complement system in DDD cases and controls using PCR, restriction digest and bidirectional sequencing. We have been able to identify novel mutations, allele variants and haplotypes in several genes of the complement system which are associated with the DDD phenotype based on statistical analyses. Since we have identified several genes associated with DDD, we have determined possible gene-gene interactions using computational analyses. We have found a strong synergistic interaction between polymorphisms in CFH and C3. To ascertain if the associated allele variants had a functional impact in the complement activity of an individual, we have obtained blood samples from normal individuals and measured AP complement activity and genotyped CFH and C3 for these samples. Association between AP activity and genotypes is analyzed using statistical methods. Significant association of CFH and C3 variants with AP complement activity has been observed. We also have generated a mice deficient of CFH and Factor D (CFD). CFH deficient mice develop renal pathology similar to DDD in humans. Renal function and complement activity have been determined in the double knockout in comparison to CFH deficient and CFD deficient mice. Results have shown that absence of Factor D can inhibit complement activation in CFH mice. Our data imply that DDD is a complex genetic disease and that genes of the AP complement system contribute to level of complement activity and the pathogenesis of DDD. With this study, we hope to develop an effective diagnosis and treatment plan for DDD patients.
5

Role of Complement Regulatory Protein Properdin in Hemolytic Anemias Caused by Complement Dysregulation

Chen, Jin January 2019 (has links)
No description available.
6

Mechanisms by which Factor H Protects Trypanosoma cruzi from the Alternative Pathway of Complement.

Sugumaran Menon, Smrithi 15 June 2023 (has links)
No description available.
7

Role of Complement Regulatory Protein Properdin in Complement Activation on Platelets and in the Formation of Platelet-Leukocyte Aggregates

Saggu, Gurpanna 20 August 2014 (has links)
No description available.
8

Role of Complement Regulatory Proteins Properdin and Factor H in Platelet/Granulocyte Aggregate Formation

Blatt, Adam Z. January 2016 (has links)
No description available.
9

Sistema complemento e resposta de produção de anticorpos em ratos hipertireoideos / Complement System and response of production of antibody in rats with hyperthyroidism

Bitencourt, Claudia da Silva 15 February 2007 (has links)
Tendo em vista a ocorrência de alterações no sistema imune relacionadas ao hipertireoidismo e à participação do sistema complemento (SC) em processos imunológicos, torna-se importante investigar se os hormônios tireoidianos teriam algum efeito sobre o SC. O SC é composto de uma série de proteínas séricas e de membrana que estão envolvidas em processos da resposta imune. Considerando que os hormônios tireoidianos estão envolvidos em uma série de processos biológicos, e que tanto o hipo- quanto hipertireoidismo podem acarretar alterações importantes nestes processos, os objetivos deste trabalho foram estudar o impacto de níveis séricos elevados de hormônios tireoidianos sobre a atividade do sistema complemento e produção de anticorpos. Foram utilizados ratos machos wistar para o modelo experimental de hipertireoidismo, investigando-se a atividade lítica das vias clássica/lectina e alternativa através de ensaios hemolíticos; os níveis séricos de fator B da via alternativa através do emprego de reagente deficiente de fator B; e a produção de anticorpos anti-hemácia de carneiro (SRBC) empregando ELISA (enzyme linked immunosorbent assay) e ensaios de plaque forming cell (PFC). O hipertireoidismo induzido não resultou em alterações da atividade lítica das vias clássica/lectina. Entretanto, a elevação dos níveis séricos de hormônios tireoidianos provocou uma redução da atividade lítica de via alternativa, de forma significante em doses de 1, 5, 50 e 100g de levotiroxina/200g de peso animal após 14 dias de tratamento, e com dose a partir de 0,15g de triiodotironina/200g de peso animal, após 7 e 12 dias de tratamento. Os níveis séricos funcionais de fator B foram reduzidos nestas condições. Além disso, ocorre redução da resposta de produção de anticorpos em ratos tratados com T3 e imunizados com SRBC. Estes resultados mostram que níveis elevados de hormônio tireoideano reduzem a capacidade funcional da via alternativa do SC , avaliada pelo desencadeamento da lise em decorrência da interação com hemácias de coelho. Esta redução poderia levar a uma menor geração de fragmentos com atividade nos processos de seqüestro e apresentação do antígeno e interação com as células envolvidas na resposta imune, resultando em títulos menores de anticorpos produzidos. Estudos adicionais são necessários para avaliar estas possibilidades. As observações deste estudo podem auxiliar para o melhor entendimento do impacto biológico das disfunções hormonais sobre a atividade do sistema complemento. / Considering the alterations of the immune system that occur in the hyperthyroidism, and the involvement of the complement system (CS) in immune processes, this work aimed to investigate the effect of high levels of thyroid hormones on the CS and on the antibody production. The CS comprehends a group of serum and membrane proteins which activation leads to the generation of protein fragments or complexes with important biologic functions, such as participation in events of the immune response. Wistar adult male rats treated with thyroid hormones were used as experimental model of hyperthyroidism, to evaluate the lytic activity of classical/lectin and alternative pathways of the CS through hemolytic assays; the serum levels of factor B employing serum deficient of this component (RB); and the production of anti-sheep red blood cells (SRBC) antibodies through enzyme linked immunosorbent (ELISA) and plaque forming cell (PFC) assays. Classic and lectin pathways activity was not affected in the hyperthyroidism. However in this condition the alternative pathway activity was significantly reduced at doses of 1; 5; 50 and 100 g of thyroxine (T4) /200g of animal weight/day after 14 days of treatment, or crescent doses starting from 0,15 g of triiodothyronine (T3) for periods of 7 and 12 days of treatment. The serum levels of factor B were also reduced in these conditions. In addition, there was a reduction of the antibody response in rats treated with T3 and immunized with SRBC. These results show that the functional capacity of alternative pathway is decreased in consequence of high levels of thyroid hormones as evaluated by its lytic potency triggered by the rabbit erythrocytes. This could them lead to a reduced generation of complement fragments active in antigen sequestering and presentation, and on the interaction of cells in the immune response decreasing the antibody production. Additional studies are required to evaluate these possibilities.
10

Sistema complemento e resposta de produção de anticorpos em ratos hipertireoideos / Complement System and response of production of antibody in rats with hyperthyroidism

Claudia da Silva Bitencourt 15 February 2007 (has links)
Tendo em vista a ocorrência de alterações no sistema imune relacionadas ao hipertireoidismo e à participação do sistema complemento (SC) em processos imunológicos, torna-se importante investigar se os hormônios tireoidianos teriam algum efeito sobre o SC. O SC é composto de uma série de proteínas séricas e de membrana que estão envolvidas em processos da resposta imune. Considerando que os hormônios tireoidianos estão envolvidos em uma série de processos biológicos, e que tanto o hipo- quanto hipertireoidismo podem acarretar alterações importantes nestes processos, os objetivos deste trabalho foram estudar o impacto de níveis séricos elevados de hormônios tireoidianos sobre a atividade do sistema complemento e produção de anticorpos. Foram utilizados ratos machos wistar para o modelo experimental de hipertireoidismo, investigando-se a atividade lítica das vias clássica/lectina e alternativa através de ensaios hemolíticos; os níveis séricos de fator B da via alternativa através do emprego de reagente deficiente de fator B; e a produção de anticorpos anti-hemácia de carneiro (SRBC) empregando ELISA (enzyme linked immunosorbent assay) e ensaios de plaque forming cell (PFC). O hipertireoidismo induzido não resultou em alterações da atividade lítica das vias clássica/lectina. Entretanto, a elevação dos níveis séricos de hormônios tireoidianos provocou uma redução da atividade lítica de via alternativa, de forma significante em doses de 1, 5, 50 e 100g de levotiroxina/200g de peso animal após 14 dias de tratamento, e com dose a partir de 0,15g de triiodotironina/200g de peso animal, após 7 e 12 dias de tratamento. Os níveis séricos funcionais de fator B foram reduzidos nestas condições. Além disso, ocorre redução da resposta de produção de anticorpos em ratos tratados com T3 e imunizados com SRBC. Estes resultados mostram que níveis elevados de hormônio tireoideano reduzem a capacidade funcional da via alternativa do SC , avaliada pelo desencadeamento da lise em decorrência da interação com hemácias de coelho. Esta redução poderia levar a uma menor geração de fragmentos com atividade nos processos de seqüestro e apresentação do antígeno e interação com as células envolvidas na resposta imune, resultando em títulos menores de anticorpos produzidos. Estudos adicionais são necessários para avaliar estas possibilidades. As observações deste estudo podem auxiliar para o melhor entendimento do impacto biológico das disfunções hormonais sobre a atividade do sistema complemento. / Considering the alterations of the immune system that occur in the hyperthyroidism, and the involvement of the complement system (CS) in immune processes, this work aimed to investigate the effect of high levels of thyroid hormones on the CS and on the antibody production. The CS comprehends a group of serum and membrane proteins which activation leads to the generation of protein fragments or complexes with important biologic functions, such as participation in events of the immune response. Wistar adult male rats treated with thyroid hormones were used as experimental model of hyperthyroidism, to evaluate the lytic activity of classical/lectin and alternative pathways of the CS through hemolytic assays; the serum levels of factor B employing serum deficient of this component (RB); and the production of anti-sheep red blood cells (SRBC) antibodies through enzyme linked immunosorbent (ELISA) and plaque forming cell (PFC) assays. Classic and lectin pathways activity was not affected in the hyperthyroidism. However in this condition the alternative pathway activity was significantly reduced at doses of 1; 5; 50 and 100 g of thyroxine (T4) /200g of animal weight/day after 14 days of treatment, or crescent doses starting from 0,15 g of triiodothyronine (T3) for periods of 7 and 12 days of treatment. The serum levels of factor B were also reduced in these conditions. In addition, there was a reduction of the antibody response in rats treated with T3 and immunized with SRBC. These results show that the functional capacity of alternative pathway is decreased in consequence of high levels of thyroid hormones as evaluated by its lytic potency triggered by the rabbit erythrocytes. This could them lead to a reduced generation of complement fragments active in antigen sequestering and presentation, and on the interaction of cells in the immune response decreasing the antibody production. Additional studies are required to evaluate these possibilities.

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