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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 effects of air pollution particles on clearance mechanisms within the lung

Barlow, Peter George January 2004 (has links)
The effects of inhaled air pollution particles on lung clearance mechanisms is an important factor in understanding how the mammalian lung deals with such pollutants and, as such, how exposure to these pollutants can be regulated. The nanoparticle(diameter S lOOnm) and transition metal components of PMIO (particulate matter with a diameter less than lO~m) have been implicated as playing major roles in the impairment of alveolar macrophage function and the subsequent retention of particles in the respiratory system. The aim of this study was to investigate the effects of components of PMIO on macrophage functions both directly, by examining macrophage phagocytosis and migration, and indirectly, by studying peripheral factors affecting macrophagefunction such as recruitment by type II cells and complement based mechanisms. We hypothesised that the alveolar epithelial type II cell line would release leukocyte chemoattractants in response to particle exposure and that this could be measured by use of a macrophage migration assay. A sub-toxic dose (125 ~g/ml)of surrogate air pollutionparticles (fine and nanoparticle carbon black and titanium dioxide) was established by measuring LOH release from a murine alveolar macrophage cell line (1774.2) and an alveolar epithelial type II cell line (L-2) in response to particle exposure. Optimisation ofa chemotaxis assay and measurement of macrophage migration towards conditioned medium obtained from the particle-exposed type II cells was conducted and it was determined that carbon black nanoparticles induced type II cells to secrete a chemoattractant that resulted in significant increases in macrophage migration compared to the negative control. This was in contrast to other particle types tested in this study which did not induce any increases in macrophage migration. It was also hypothesised that complement proteins could be involved in macrophage recruitment to sites of particle deposition and, as such, the migration of macrophages towards particle exposed blood serum was examined in vitro. Foetal bovine serum (FBS) was exposed to fine and nanoparticle caroon black and titanium dioxide (l-Smg/ml) for 2 hours. It was found, in accord with the previous study involving type II cells, that carbon black nanoparticles could activate the generation of chemotactic factors in serum that could subsequently induce significant increases (p < 0.001) in macrophage migration when serum was diluted to 10% using serum-free RPMI 1640 culture medium. This effect could be ameliorated by co-incubating the particle-treated serum in the presence of the antioxidant Trolox suggesting that oxidative stress played a role in the generation of the chemoattractant molecules. However, incubation of the serum with a pure oxidant at a range of doses did not result in the generation of chemotactic molecules suggesting that another factor could be involved in the chemoattractant generation. Further investigation to determine the exact molecular mechanism behind the chemoattractant generation is warranted. In contrast to the previous studies, we have also found evidence that components of PM₁₀ can cause decreased efficacy of macrophage clearance mechanisms in vivo and in vitro. It was hypothesised that PM₁₀ instillation would result in a decrease in macrophage phagocytic potential and an increase in chemotactic potential ex vivo. Rats were instilled with 125 and 250μg of PM₁₀ collected from North Kensington, London or sterile saline (negative control). Post-instillation (18 hours), significantly elevated concentrations of TNFa were detected in the BAL fluid together with a significant increase in the number of BAL neutrophils. Phagocytosis and chemotaxis assays conducted with BAL macrophages ex vivo showed that macrophage migration towards a positive chemoattractant, Zymosan Activated Serum (ZAS), was significantly lower than the macrophages obtained from the negative control rats. Macrophage phagocytosis of latex beads ex vivo was also found to be significantly decreased when PM₁₀ was visible inside the cell. An in vitro study where a macrophage cell line (J774.Al) was exposed to a low dose of nanoparticle carbon black (31.25μg) together with varying concentrations (100μM - 100nM) of zinc chloride (ZnCl₂) was also conducted. Exposure of macrophages to nanoparticle carbon black and zinc chloride alone induced a decrease in macrophage phagocytosis. It was found that when macrophages were co-exposed to nanoparticle carbon black and ZnCl₂, there was an additive decrease in macrophage phagocytic potential. The results contained within this manuscript demonstrate that the components of PM₁₀ can induce adverse effects on specific aspects of macrophage clearance mechanisms, but that nanoparticles can also stimulate the production of chemoattractants to aid in the recruitment of phagocytes and subsequent particle clearance. Although a contrary relationship appears to exist between these findings, the recruitment of leukocytes in response to particulate exposure is a mechanism that supports particle clearance. However, the retardation of phagocytic and chemotactic mechanisms in particle exposed macrophages may help to explain the increased toxicity, inflammation and retention time observed with nanoparticle inhalation.
2

Qualidade microbiana: influência de corantes e pigmento no método de bioluminescência / Microbiology quality: Influence of dyes and pigment to bioluminescence method

Mattos, Angela Franco 05 September 2005 (has links)
A análise da qualidade microbiana de matérias-primas e de produtos por meio da técnica convencional de contagem de microrganismos exige demanda elevada de trabalho e fornece resultados em período de tempo não compatível com o desenvolvimento da tecnologia. A indústria farmacêutica e cosmética necessita de liberação rápida de seus produtos, assim métodos alternativos podem reduzir o tempo de trabalho e custo. O método de ATP bioluminescência detecta a presença ou ausência de microrganismos em até 24 horas. O método baseia-se na reação do ATP (adenosina trifosfato) provenientes do microrganismo com o complexo luciferina - luciferase, produzindo luz. Os componentes da formulação de produtos cosméticos, como os corantes e os pigmentos podem interferir na reação e influenciar na leitura da Unidade Relativa de Luz (URL). O objetivo do experimento foi validar método de ATP bioluminescência para avaliação da qualidade microbiana do pigmento Green Nº 7 e dos corantes FD&C Blue Covanor e o FD&C Red Nº 5, usados em produtos cosméticos, verificando se esses podem interferir na reação de ATP-bioluminescência , utilizando os meios de cultura TAT(Tryptone-Azolectin-Tween) , DE ( Dey Engly Neutralization Broth) e LB (Letheen Broth) . A primeira etapa da validação do sistema ATP bioluminescência foi determinar o Efeito da Amostra nas suspensões o qual verifica a presença de ATP não microbiano. A sensibilidade do ensaio foi analisada por meio do teste de limite de detecção inoculando-se os microorganismos Escherichia coli ATCC 8739, Burkholderia cepacea ATCC 25416, Staphylococcus aureus ATCC 6538, Candida albicans ATCC 10231 na suspensão das amostras. Para C. albicans não foi possível a detecção pois houve a necessidade de tempo maior de incubação. O meio de cultura TAT sem acréscimo de polissorbato 80 apresentou as melhores condições para a validação do pigmento Green Nº 7. Para corantes há necessidade ainda de uma investigação mais criteriosa, estudando outros meios de cultura, reagentes e condições que propiciem resultados adequados em conformidade com as especificações para a validação. / The analysis of the microbiology quality of raw materiais and finished products by means of the conventional technique of counting of microorganism demands high time of work and supplies resulted in period of not compatible time with the development of the technology. The rapid methods provide reliable and cost effective analysis for the microbiological evaluation the pharmaceutical and cosmetic industry. The ATP Bioluminescence detect the presence or absence of microorganisms the reduction in detection times and analysis from 72 hours to 24 hours. The bioluminescence assay is based upon the light-producing enzyme luciferase that will hydrolyze ATP to produce light. Light production is detected by a luminometer and recorded as relative light units (RLU). The purpose of this investigation was to develop and validate the use an ATP bioluminescence assay for detection microbial contamination in artificially contaminated commercial Green Nº 7 pigment and FD&C Blue Covanor e o FD&C Red Nº 5 dyes with some microbial cultures, TAT (Tryptone-Azolectin-Tween) , DE (Dey Engly Neutralization Broth) e LB (Letheen Broth), and to compare the results against standard microbiological analysis. The first step in validation of the ATP bioluminescence system was to determine the sample effect of the sample suspensions on the bioluminescence reaction where analyzed to determine whether the sample contained nonmicrobial ATP. The sensitivity of the assay to detect different levels of Escherichia coli ATCC 8739, Burkholderia cepacea ATCC 25416, Staphylococcus aureus ATCC 6538, Candida albicans ATCC 10231 was analyzed by spiking into the samples suspensions. For C. albicans contamination detection has not been possible because it has required more time than bacteria. The microbial culture TAT without addition of polissorbato 80 has presented the best conditions for the validation of the Green pigment n° 7. For dyes has still been necessity of studying other microbial culture, reagents and conditions that they propitiate resulted adequate in compliance with the specifications for the validation.
3

Qualidade microbiana: influência de corantes e pigmento no método de bioluminescência / Microbiology quality: Influence of dyes and pigment to bioluminescence method

Angela Franco Mattos 05 September 2005 (has links)
A análise da qualidade microbiana de matérias-primas e de produtos por meio da técnica convencional de contagem de microrganismos exige demanda elevada de trabalho e fornece resultados em período de tempo não compatível com o desenvolvimento da tecnologia. A indústria farmacêutica e cosmética necessita de liberação rápida de seus produtos, assim métodos alternativos podem reduzir o tempo de trabalho e custo. O método de ATP bioluminescência detecta a presença ou ausência de microrganismos em até 24 horas. O método baseia-se na reação do ATP (adenosina trifosfato) provenientes do microrganismo com o complexo luciferina - luciferase, produzindo luz. Os componentes da formulação de produtos cosméticos, como os corantes e os pigmentos podem interferir na reação e influenciar na leitura da Unidade Relativa de Luz (URL). O objetivo do experimento foi validar método de ATP bioluminescência para avaliação da qualidade microbiana do pigmento Green Nº 7 e dos corantes FD&C Blue Covanor e o FD&C Red Nº 5, usados em produtos cosméticos, verificando se esses podem interferir na reação de ATP-bioluminescência , utilizando os meios de cultura TAT(Tryptone-Azolectin-Tween) , DE ( Dey Engly Neutralization Broth) e LB (Letheen Broth) . A primeira etapa da validação do sistema ATP bioluminescência foi determinar o Efeito da Amostra nas suspensões o qual verifica a presença de ATP não microbiano. A sensibilidade do ensaio foi analisada por meio do teste de limite de detecção inoculando-se os microorganismos Escherichia coli ATCC 8739, Burkholderia cepacea ATCC 25416, Staphylococcus aureus ATCC 6538, Candida albicans ATCC 10231 na suspensão das amostras. Para C. albicans não foi possível a detecção pois houve a necessidade de tempo maior de incubação. O meio de cultura TAT sem acréscimo de polissorbato 80 apresentou as melhores condições para a validação do pigmento Green Nº 7. Para corantes há necessidade ainda de uma investigação mais criteriosa, estudando outros meios de cultura, reagentes e condições que propiciem resultados adequados em conformidade com as especificações para a validação. / The analysis of the microbiology quality of raw materiais and finished products by means of the conventional technique of counting of microorganism demands high time of work and supplies resulted in period of not compatible time with the development of the technology. The rapid methods provide reliable and cost effective analysis for the microbiological evaluation the pharmaceutical and cosmetic industry. The ATP Bioluminescence detect the presence or absence of microorganisms the reduction in detection times and analysis from 72 hours to 24 hours. The bioluminescence assay is based upon the light-producing enzyme luciferase that will hydrolyze ATP to produce light. Light production is detected by a luminometer and recorded as relative light units (RLU). The purpose of this investigation was to develop and validate the use an ATP bioluminescence assay for detection microbial contamination in artificially contaminated commercial Green Nº 7 pigment and FD&C Blue Covanor e o FD&C Red Nº 5 dyes with some microbial cultures, TAT (Tryptone-Azolectin-Tween) , DE (Dey Engly Neutralization Broth) e LB (Letheen Broth), and to compare the results against standard microbiological analysis. The first step in validation of the ATP bioluminescence system was to determine the sample effect of the sample suspensions on the bioluminescence reaction where analyzed to determine whether the sample contained nonmicrobial ATP. The sensitivity of the assay to detect different levels of Escherichia coli ATCC 8739, Burkholderia cepacea ATCC 25416, Staphylococcus aureus ATCC 6538, Candida albicans ATCC 10231 was analyzed by spiking into the samples suspensions. For C. albicans contamination detection has not been possible because it has required more time than bacteria. The microbial culture TAT without addition of polissorbato 80 has presented the best conditions for the validation of the Green pigment n° 7. For dyes has still been necessity of studying other microbial culture, reagents and conditions that they propitiate resulted adequate in compliance with the specifications for the validation.

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