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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

Characterisation and ontogeny of natural killer cells in Xenopus laevis

Stewart, Rebecca January 2002 (has links)
The initial aim of the work described in this Thesis was to investigate the lymphoid organ distribution, phenotype and function of the lymphocyte population identified by candidate anti-Xenopus natural killer (NK) cell monoclonal antibodies (mAb's). Since removal of the thymus gland early in larval life (thymectomy) results in the eradication of T-cells and subsequent increase in the proportion of candidate NK cells, thymectomised (Tx) Xenopus were integral in the study of this subset of lymphocytes. Phenotypic and functional studies respectively demonstrated that mAb-defined candidate NK cells do not belong to the B- or T-cell lineage and display cytotoxic activity towards MHC class-Ia-deficient tumour target cells, strengthening the contention that these cells represent the NK subset in Xenopus. The ontogeny of NK cells was investigated in relation to the emergence of the NK cell inhibitory ligand, MHC class-L Splenic NK cells were found to emerge in 6-7 week-old larvae (stage 56-58), which is ≈5 weeks after T- and B-cells become detectable, and some 2 weeks after MHC-Ia is first detected. However, these cells do not appear to be functionally competent until 6 months of age. The expression and ontogeny of recently cloned β2m (the molecule essential for MHC class-I expression) was also briefly investigated. β2m (both RNA and protein) was detectable in all adult tissues and cell lines, even class-I-deficient tumour cells; β2m transcripts were found in 5 week-old larvae that lack MHC class-I. The emergence of NK antigen on a population of T-cells following in vitro stimulation of splenocytes with PMA and calcium ionophore presented the opportunity to biochemically characterise (through immunoprecipitation) the mAb-defined NK antigen. Proteins precipitated using the anti-NK mAb were either surface labelled with biotin, or metabolically labelled with (^35)S. Both techniques resulted in the detection of a protein 55kDa in size.
2

An investigation into the mechanism of action of amphiphilies with antineoplastic properties

Dymond, Marcus Karl January 2001 (has links)
No description available.
3

Characterization and Immune Inactivation of Cytotoxicity of Mycoplasma Species

Sayed, Iftikhar Ali 12 1900 (has links)
Polyacrymalide gel isoelectric focusing (PAGIF) in thin-layer was used to resolve proteins of Mycoplasma spp., Acholeplasma spp. and of eight strains of Ureaplasma urealyticum (T-Strain). A mixture of urea, Triton X-100, and dithioerythritol was used to solubilize sonically disrupted cells.
4

Targeting fusogenic retroviral glycoproteins by ligand display

Fielding, Adel Kay January 1999 (has links)
No description available.
5

Fitodesinfecção aplicada a águas na perspectiva da agricultura familiar

Gonçalves, Alexandre Rocha January 2005 (has links)
As previsões mais otimistas para o mundo no segundo milênio alertam para a escassez de água. Esta terá como origem a redução de volume de água doce aproveitável, o desperdício e poluição das fontes de água. O cloro, usado para a desinfecção, se combina com os resíduos de matéria orgânica remanescente do tratamento da água de consumo formando os organoclorados (produtos potencialmente cancerígenos). A proposta deste trabalho, é oferecer subsídio à sanitização da água buscando, pelo resgate etnográfico, recursos naturais sustentáveis, renováveis e ecologicamente corretos como alternativa para o tratamento da água na pequena propriedade rural. Das dezoito plantas indicadas e triadas na forma de extratos hidro-alcoólicos quanto a Intensidade de Atividade Antibacteriana (IAAB), selecionou-se os cinco que tiveram o melhor desempenho no controle das bactérias em teste (duas gram positivas e duas gram negativas). Os extratos escolhidos passaram pelo teste de Concentração Inibitória Mínima/Concentração Bactericida Mínima (CIM/CBM). O que mais se destacou foi o extrato de Sete Sangrias (Cuphea Carthagenensis (Jacq.) Macbride) que controlou as bactérias desafiantes até a concentração de 10%. Estes extratos também foram testados quanto à citotoxicidade e constatou-se que a Baleeira (Cordia curassavica), Folha da Fortuna (Bryophyllum pinatum Kurz.) e a Sete Sangrias (Cuphea cathagenensis (Jacq.) Macbride) foram citotóxicas em concentrações entre 1 e 10 % sem diferença estatística para o teste de Duncam (p=0,99).Embora a confrontação da capacidade desinfetante e o efeito tóxico apresentados pelos extratos de plantas sejam considerados animadores, não os recomendamos para uso como desinfetantes de volumes hídricos uma vez que a concentração mais baixa efetiva foi a de 10%. / The most optimistic forecast for the world in the second millennium calls attention to the water shortage. This shortage will have as its origin the reduction of volume of useable fresh water, waste and pollution of the water resources. The chlorine, used for disinfection, combines with the residues of organic matter remaining from the treatment of water for consumption forming organochlorides (potentially carcinogenic products). The aim of this work is to offer options to the sanitation of water searching, by ethnographic rescue, natural resources which are sustainable, renewable and ecologically correct as an alternative for water treatment in small rural farms. From the eighteen plants indicated and screened in the form of hydroalcoholic extracts regarding their Antibacterial Activity Intensity (IAAB), the five that showed better performance in the control of bacteria (two Gram positive and two Gram negative), were selected. The chosen extracts were submitted to the test of Minimal Inhibitory Concentration/ Minimal Bactericide Concentration (CIM/CBM). The one that showed the best performance was Sete Sangrias (Cuphea Carthagenensis (Jacq.) Macbride), which controlled the tested bacteria dilution up to 10%. These extracts were also tested regarding their cytotoxicity and it was verified that Baleeira (Cordia curassavica), Folha da Fortuna (Bryophyllum pinatum Kurz.) and Sete sangrias (Cuphea cathagenensis (Jacq.) Macbride) were cytotoxic in concentrations between 1 and 10%, without statistic difference by the Duncam test (p=0,99). Although the confrontation of disinfection capacity and the toxic effect presented by the plant extracts are considered encouraging, we do not recommend them for use as disinfectants of water, as the lowest effective concentration obtained was 10%.
6

The role of cytokines, coagulation and fibrinolysis in leucocyte and LAK cell cytotoxicity of tumour cells

Biggerstaff, John Patrick January 2012 (has links)
Interleukin-2 activates lymphocytes to become highly cytotoxic for a wide range of tumour cell types in vitro (Iymphokine activated killer or LAK cells), and in animal models. However, only limited therapeutic benefit was observed in clinical trials of LAK cell therapy. This project aimed to investigate the molecular and cellular interactions involved in the production and effector functions of LAK cells, to identify factor(s) which might be responsible for the poor clinical responses observed in LAK cell therapy. Tumour cell lines were heterogeneous in their response to killing by cytokines (TNFα, LT, IFNγ and IL-1β), and purified monocytes or lymphocytes, but were consistently highly sensitive to LAK cell cytotoxicity. Autologous monocytes and lymphocytes were not killed by LAK cells, in contrast to human umbilical vein endothelial cells and fibroblasts. Supernatants from LAK cells were considerably less cytotoxic than the effector cells, and physical separation of effector and target cells resulted in inhibition of killing. Lymphocyte and LAK cell cytotoxicity was associated predominantly with the CD8+ (cytotoxic T-cell) lymphocyte sub-population, and was significantly inhibited by anti-TNFα and anti-LT, demonstrating that these cytokines were the primary effector molecules in this system. LAK cells and A375 melanoma cells showed procoagulant activity, predominantly via the tissue factor pathway, and LAK cells also possessed surface factor V. In addition, A375 cells were highly fibrinolytic. Tumour cell killing by LAK cells was inhibited by plasma, and further experiments determined that polymerised fibrin, but not fibrin monomer was responsible. From these results it was suggested that culture of small numbers of cells from tumour biopsies, and the determination of their sensitivity to cytotoxic drugs, cytokines and effector cells may lead to more effective treatment protocols for immunotherapy of individual tumours. In order to enhance the efficacy of immunotherapy, further in vivo research is required to elucidate the interactions between immune effector cells and the coagulation/fibrinolytic systems.
7

Fitodesinfecção aplicada a águas na perspectiva da agricultura familiar

Gonçalves, Alexandre Rocha January 2005 (has links)
As previsões mais otimistas para o mundo no segundo milênio alertam para a escassez de água. Esta terá como origem a redução de volume de água doce aproveitável, o desperdício e poluição das fontes de água. O cloro, usado para a desinfecção, se combina com os resíduos de matéria orgânica remanescente do tratamento da água de consumo formando os organoclorados (produtos potencialmente cancerígenos). A proposta deste trabalho, é oferecer subsídio à sanitização da água buscando, pelo resgate etnográfico, recursos naturais sustentáveis, renováveis e ecologicamente corretos como alternativa para o tratamento da água na pequena propriedade rural. Das dezoito plantas indicadas e triadas na forma de extratos hidro-alcoólicos quanto a Intensidade de Atividade Antibacteriana (IAAB), selecionou-se os cinco que tiveram o melhor desempenho no controle das bactérias em teste (duas gram positivas e duas gram negativas). Os extratos escolhidos passaram pelo teste de Concentração Inibitória Mínima/Concentração Bactericida Mínima (CIM/CBM). O que mais se destacou foi o extrato de Sete Sangrias (Cuphea Carthagenensis (Jacq.) Macbride) que controlou as bactérias desafiantes até a concentração de 10%. Estes extratos também foram testados quanto à citotoxicidade e constatou-se que a Baleeira (Cordia curassavica), Folha da Fortuna (Bryophyllum pinatum Kurz.) e a Sete Sangrias (Cuphea cathagenensis (Jacq.) Macbride) foram citotóxicas em concentrações entre 1 e 10 % sem diferença estatística para o teste de Duncam (p=0,99).Embora a confrontação da capacidade desinfetante e o efeito tóxico apresentados pelos extratos de plantas sejam considerados animadores, não os recomendamos para uso como desinfetantes de volumes hídricos uma vez que a concentração mais baixa efetiva foi a de 10%. / The most optimistic forecast for the world in the second millennium calls attention to the water shortage. This shortage will have as its origin the reduction of volume of useable fresh water, waste and pollution of the water resources. The chlorine, used for disinfection, combines with the residues of organic matter remaining from the treatment of water for consumption forming organochlorides (potentially carcinogenic products). The aim of this work is to offer options to the sanitation of water searching, by ethnographic rescue, natural resources which are sustainable, renewable and ecologically correct as an alternative for water treatment in small rural farms. From the eighteen plants indicated and screened in the form of hydroalcoholic extracts regarding their Antibacterial Activity Intensity (IAAB), the five that showed better performance in the control of bacteria (two Gram positive and two Gram negative), were selected. The chosen extracts were submitted to the test of Minimal Inhibitory Concentration/ Minimal Bactericide Concentration (CIM/CBM). The one that showed the best performance was Sete Sangrias (Cuphea Carthagenensis (Jacq.) Macbride), which controlled the tested bacteria dilution up to 10%. These extracts were also tested regarding their cytotoxicity and it was verified that Baleeira (Cordia curassavica), Folha da Fortuna (Bryophyllum pinatum Kurz.) and Sete sangrias (Cuphea cathagenensis (Jacq.) Macbride) were cytotoxic in concentrations between 1 and 10%, without statistic difference by the Duncam test (p=0,99). Although the confrontation of disinfection capacity and the toxic effect presented by the plant extracts are considered encouraging, we do not recommend them for use as disinfectants of water, as the lowest effective concentration obtained was 10%.
8

Fitodesinfecção aplicada a águas na perspectiva da agricultura familiar

Gonçalves, Alexandre Rocha January 2005 (has links)
As previsões mais otimistas para o mundo no segundo milênio alertam para a escassez de água. Esta terá como origem a redução de volume de água doce aproveitável, o desperdício e poluição das fontes de água. O cloro, usado para a desinfecção, se combina com os resíduos de matéria orgânica remanescente do tratamento da água de consumo formando os organoclorados (produtos potencialmente cancerígenos). A proposta deste trabalho, é oferecer subsídio à sanitização da água buscando, pelo resgate etnográfico, recursos naturais sustentáveis, renováveis e ecologicamente corretos como alternativa para o tratamento da água na pequena propriedade rural. Das dezoito plantas indicadas e triadas na forma de extratos hidro-alcoólicos quanto a Intensidade de Atividade Antibacteriana (IAAB), selecionou-se os cinco que tiveram o melhor desempenho no controle das bactérias em teste (duas gram positivas e duas gram negativas). Os extratos escolhidos passaram pelo teste de Concentração Inibitória Mínima/Concentração Bactericida Mínima (CIM/CBM). O que mais se destacou foi o extrato de Sete Sangrias (Cuphea Carthagenensis (Jacq.) Macbride) que controlou as bactérias desafiantes até a concentração de 10%. Estes extratos também foram testados quanto à citotoxicidade e constatou-se que a Baleeira (Cordia curassavica), Folha da Fortuna (Bryophyllum pinatum Kurz.) e a Sete Sangrias (Cuphea cathagenensis (Jacq.) Macbride) foram citotóxicas em concentrações entre 1 e 10 % sem diferença estatística para o teste de Duncam (p=0,99).Embora a confrontação da capacidade desinfetante e o efeito tóxico apresentados pelos extratos de plantas sejam considerados animadores, não os recomendamos para uso como desinfetantes de volumes hídricos uma vez que a concentração mais baixa efetiva foi a de 10%. / The most optimistic forecast for the world in the second millennium calls attention to the water shortage. This shortage will have as its origin the reduction of volume of useable fresh water, waste and pollution of the water resources. The chlorine, used for disinfection, combines with the residues of organic matter remaining from the treatment of water for consumption forming organochlorides (potentially carcinogenic products). The aim of this work is to offer options to the sanitation of water searching, by ethnographic rescue, natural resources which are sustainable, renewable and ecologically correct as an alternative for water treatment in small rural farms. From the eighteen plants indicated and screened in the form of hydroalcoholic extracts regarding their Antibacterial Activity Intensity (IAAB), the five that showed better performance in the control of bacteria (two Gram positive and two Gram negative), were selected. The chosen extracts were submitted to the test of Minimal Inhibitory Concentration/ Minimal Bactericide Concentration (CIM/CBM). The one that showed the best performance was Sete Sangrias (Cuphea Carthagenensis (Jacq.) Macbride), which controlled the tested bacteria dilution up to 10%. These extracts were also tested regarding their cytotoxicity and it was verified that Baleeira (Cordia curassavica), Folha da Fortuna (Bryophyllum pinatum Kurz.) and Sete sangrias (Cuphea cathagenensis (Jacq.) Macbride) were cytotoxic in concentrations between 1 and 10%, without statistic difference by the Duncam test (p=0,99). Although the confrontation of disinfection capacity and the toxic effect presented by the plant extracts are considered encouraging, we do not recommend them for use as disinfectants of water, as the lowest effective concentration obtained was 10%.
9

Human Decidual CD8+ T Cells have Phenotypic and Functional Heterogeneity

Alexander, Aria January 2021 (has links)
No description available.
10

Avaliação da genotoxicidade e mutagenicidade de misturas comerciais de diesel e biodiesel puras e em simulações de vazamento em água e solo /

Leme, Daniela Morais. January 2010 (has links)
Orientador: Maria Aparecida Marin Morales / Banca: Vera Maria Ferrão Vargas / Banca: Mary Rosa Rodrigues de Marchi / Banca: Danielle Palma de Oliveira / Banca: Paula Suares Rocha / Resumo: A questão energética é hoje um tema de preocupação mundial. A limitação das fontes de energia fóssil e seus efeitos indesejáveis ao meio ambiente têm estimulado a busca de novas fontes alternativas, desde que renováveis. Em diversos países, como no Brasil, têm sido destinados grandes incentivos ao desenvolvimento do setor de biocombustíveis, no qual se inclui o biodiesel. O futuro promissor do biodiesel está relacionado não apenas ao fato de ser um combustível renovável, mas também às suas contribuições na redução da emissão de poluentes atmosféricos e à sua maior degradabilidade, em relação aos combustíveis fósseis. No entanto, poucos são os estudos realizados com o biodiesel para avaliar os seus possíveis impactos, quando usados puro ou em misturas ao óleo diesel, sobre o ambiente (principalmente corpos d'águas e solos) e sobre os organismos vivos, em caso de uma possível contaminação ambiental. O presente estudo teve como objetivo avaliar a citotoxicidade, genotoxicidade e mutagenicidade do biodiesel e de suas misturas com diesel (B5, B20 e B50), por meio de simulações de vazamento em água e solo. As simulações foram realizadas no verão, para caracterizar um vazamento em condições tropicais, sendo aplicados diferentes ensaios biológicos [teste de Allium cepa, ensaio Salmonella/microssoma, ensaios de mutagenicidade com células CHO-K1 e HepG2 in vitro, ensaio para detecção de indução de morte celular (alterações do ΔΨm, externalização da fosfatidilserina), avaliação da citotoxicidade em tempo real (sistema xCELLigence™)] nas amostras de água e solo obtidas nos experimentos. Foi observada no presente estudo uma significativa citotoxicidade, que foi relacionada com constituintes do óleo diesel, mais especificamente, com os hidrocarbonetos policíclicos aromáticos (PAHs). Já os efeitos genotóxicos/mutagênicos, observados... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The energy-related issue is currently a subject that causes world concern. The limitations of fossil energy sources and their undesirable effects upon the environment have encouraged the search for new alternative sources, as long as they are renewable ones. In several countries, like Brazil, great incentives have been allocated to the development of the biofuel sector, and that includes biodiesel. The promising future of biodiesel is related not only the fact of being a renewable biofuel, but also to its contribution to reducing release of air pollutants and its higher degradability when compared to fossil fuels. Nevertheless, not enough studies have been conducted with biodiesel to evaluate their possible impacts - either when they are used crude or in biodiesel blends - upon both the environment (especially water bodies and soils) and living organisms, should there be environmental contamination. The aim of this study was to assess toxicity, genotoxicity and mutagenicity of biodiesel and its diesel blends (B5, B20 and B50), by simulating spills into water and soil. The simulations were carried out in the summer in order to characterize a spill under tropical conditions, and different assays [Allium cepa test, Salmonella mutagenicity assay, in vitro mutagenicity assays with CHO-K1 and HepG2 cells line, detection of cell death inductions (changes in ΔΨm, phosphatidylserine externalization), cytotoxicity assessment by xCELLigence™ system] were conducted using soil and water samples obtained in the experiment. In this study, significant citotoxicity was observed, which was found to be related to biodiesel contaminants, even more specifically, to its polycyclic aromatic hydrocarbons (PAHs). On the other hand, the genotoxic/mutagenic effects observed in the other assays done with diesel and biodiesel proved to result from the action of pollutants present in the raw material used... (Complete abstract click electronic access below) / Doutor

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