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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.
231

Avaliação biológica de nanocarreadores de doxorrubicina em células de câncer de bexiga / Biological evaluation of doxorubicin nanocarriers in bladder cancer cells

Gaspari, Alexandre Rodrigues 19 October 2018 (has links)
O carcinoma da bexiga urinária (CB) é a segunda doença maligna mais frequente do trato urinário. Devido a baixa eficácia dos tratamentos intravesicais atuais (imunoterapia com BCG e quimioterapia), seja pelo baixo tempo de residência do fármaco na bexiga ou pela baixa permeabilidade no urotélio, novas estratégias que aumentem esse tempo de residência do fármaco e sua penetração na bexiga têm sido investigadas. Dentre estas estratégias pode-se citar os sistemas de liberação sustentada nanoestruturados, que liberam o fármaco gradativamente, protegem o fármaco encapsulado, aumenta a biodisponibilidade, aumentando a eficácia da terapia e diminuindo os efeitos adversos. Nesta linha, o objetivo desse trabalho foi produzir e utilizar carreadores lipídicos nanoestruturados (CLN) como sistema de carreamento de doxorrubicina (DOXO) e a sua avaliação biológica em células de câncer de bexiga. Os CLN, compostos por manteiga de Illipê (lipídeo sólido), ácido oleico (óleo) e o estabilizante Pluronic F68, foram preparados pelo método de emulsão a quente e sonicação. A caracterização físico-química do CLN foi realizada determinando o diâmetro hidrodinâmico médio e potencial zeta (carga superficial) por espalhamento de luz dinâmico (DLS), cristalinidade por calorimetria exploratória diferencial (DSC), eficiência de encapsulamento por espectrofotometria UV-vis, ensaio de citotoxicidade em células RT4 e análise de permeação ex vivo e in vivo das formulações aplicadas em bexiga de porco por microscopia confocal. O diâmetro hidrodinâmico médio dos CLN sem o fármaco foi de 103 nm e seu PdI (índice de polidispersão) igual a 0,2. O encapsulamento da DOXO aumentou o diâmetro dos CLN para 112 nm e o valor de PdI foi de 0,2. O baixo valor de PdI indica formulações com baixa polidispersão. Os valores de potencial zeta dos CLN sem e com DOXO foram ambos negativos, variando de -5 mV a -25 mV. Nos termogramas das amostras de CLN-DOXO não foi observado o pico referente a fusão da DOXO em 197,93ºC, indicando que o fármaco provavelmente está molecularmente disperso na matriz lipídica. Nos ensaios de citotoxicidade, a formulação CLN-DOXO mostrou-se mais citotóxica do que a DOXO livre em baixas concentrações (31-250 ng/mL). O valor de IC50 reduziu 2,1 vezes quando a DOXO foi encapsulada. Essa maior atividade antitumoral in vitro pode estar relacionada ao aumento do uptake celular como confirmado pelos ensaios de citometria de fluxo. No estudo de permeação ex vivo em bexiga de porco foram observadas permeações muito semelhantes das formulações de DOXO livre e encapsulada em CLN. Porém no ensaio in vivo a DOXO encapsulada permeou mais que a DOXO livre. Os resultados obtidos apontam para um promissor sistema de liberação de doxorrubicina para a terapia do câncer de bexiga. / Urinary bladder carcinoma (BC) is the second most common malignant disease of the urinary tract. Due to the low efficacy of current intravesical treatments (BCG immunotherapy and chemotherapy), either because of the low residence time of the drug in the bladder or due to low permeability in the urothelium, new strategies that increase the residence time of the drug and its penetration into the bladder have been investigated. These strategies include nanostructured sustained release systems, which release the drug gradually, protect the encapsulated drug, increase the bioavailability; increasing the effectiveness of the therapy and reducing side effects. In this line, the aim of this work was to produce and apply nanostructured lipid carriers (NLC) as a doxorubicin delivery system (DOXO) and its biological evaluation in bladder cancer cells. The NLC, composed by Illipe butter (solid lipid), oleic acid (oil) and Pluronic F68 stabilizer, were prepared by the hot emulsion and sonication method. The physical-chemical characterization of these NLC was performed by measured the mean hydrodynamic diameter and zeta potential (surface charge) by dynamic light scattering (DLS), crystallinity by differential scanning calorimetry (DSC), encapsulation efficiency by UV-vis spectrophotometry, cytotoxicity assay in RT4 cells and ex vivo and in vivo permeation assay of formulations applied to pig bladder by confocal microscopy. The mean hydrodynamic diameter of NLC without the drug was 103 nm and its PdI (polydispersity index) was 0.2. The encapsulation of DOXO increased the NLC diameter to 112 nm and the PdI value was 0.2. The low value of PdI indicates formulations with low polydispersion. The zeta potential values of the NLC without and with DOXO were both negative (-5 mV to -25 mV). In the thermograms of the NLC-DOXO sample the fusion peak of DOXO at 197.93 was not observed, indicating that the drug is molecularly dispersed in the lipid matrix. In the cytotoxicity assays, the NLC-DOXO formulation was more cytotoxic than free DOXO at low concentrations (31-250 ng/mL). The IC50 value was reduced 2.1 fold when DOXO was encapsulated. This increased in vitro antitumor activity may be related to increased cell uptake as confirmed by flow cytometry analysis. In the ex vivo permeation study in the pig bladder, a very similar permeation was observed between free and encapsulated DOXO. However, in the in vivo assay the encapsulated DOXO permeated more than free DOXO. The results indicates a promising release system of doxorubicin to bladder cancer therapy.
232

Avaliação biológica de nanocarreadores de doxorrubicina em células de câncer de bexiga / Biological evaluation of doxorubicin nanocarriers in bladder cancer cells

Alexandre Rodrigues Gaspari 19 October 2018 (has links)
O carcinoma da bexiga urinária (CB) é a segunda doença maligna mais frequente do trato urinário. Devido a baixa eficácia dos tratamentos intravesicais atuais (imunoterapia com BCG e quimioterapia), seja pelo baixo tempo de residência do fármaco na bexiga ou pela baixa permeabilidade no urotélio, novas estratégias que aumentem esse tempo de residência do fármaco e sua penetração na bexiga têm sido investigadas. Dentre estas estratégias pode-se citar os sistemas de liberação sustentada nanoestruturados, que liberam o fármaco gradativamente, protegem o fármaco encapsulado, aumenta a biodisponibilidade, aumentando a eficácia da terapia e diminuindo os efeitos adversos. Nesta linha, o objetivo desse trabalho foi produzir e utilizar carreadores lipídicos nanoestruturados (CLN) como sistema de carreamento de doxorrubicina (DOXO) e a sua avaliação biológica em células de câncer de bexiga. Os CLN, compostos por manteiga de Illipê (lipídeo sólido), ácido oleico (óleo) e o estabilizante Pluronic F68, foram preparados pelo método de emulsão a quente e sonicação. A caracterização físico-química do CLN foi realizada determinando o diâmetro hidrodinâmico médio e potencial zeta (carga superficial) por espalhamento de luz dinâmico (DLS), cristalinidade por calorimetria exploratória diferencial (DSC), eficiência de encapsulamento por espectrofotometria UV-vis, ensaio de citotoxicidade em células RT4 e análise de permeação ex vivo e in vivo das formulações aplicadas em bexiga de porco por microscopia confocal. O diâmetro hidrodinâmico médio dos CLN sem o fármaco foi de 103 nm e seu PdI (índice de polidispersão) igual a 0,2. O encapsulamento da DOXO aumentou o diâmetro dos CLN para 112 nm e o valor de PdI foi de 0,2. O baixo valor de PdI indica formulações com baixa polidispersão. Os valores de potencial zeta dos CLN sem e com DOXO foram ambos negativos, variando de -5 mV a -25 mV. Nos termogramas das amostras de CLN-DOXO não foi observado o pico referente a fusão da DOXO em 197,93ºC, indicando que o fármaco provavelmente está molecularmente disperso na matriz lipídica. Nos ensaios de citotoxicidade, a formulação CLN-DOXO mostrou-se mais citotóxica do que a DOXO livre em baixas concentrações (31-250 ng/mL). O valor de IC50 reduziu 2,1 vezes quando a DOXO foi encapsulada. Essa maior atividade antitumoral in vitro pode estar relacionada ao aumento do uptake celular como confirmado pelos ensaios de citometria de fluxo. No estudo de permeação ex vivo em bexiga de porco foram observadas permeações muito semelhantes das formulações de DOXO livre e encapsulada em CLN. Porém no ensaio in vivo a DOXO encapsulada permeou mais que a DOXO livre. Os resultados obtidos apontam para um promissor sistema de liberação de doxorrubicina para a terapia do câncer de bexiga. / Urinary bladder carcinoma (BC) is the second most common malignant disease of the urinary tract. Due to the low efficacy of current intravesical treatments (BCG immunotherapy and chemotherapy), either because of the low residence time of the drug in the bladder or due to low permeability in the urothelium, new strategies that increase the residence time of the drug and its penetration into the bladder have been investigated. These strategies include nanostructured sustained release systems, which release the drug gradually, protect the encapsulated drug, increase the bioavailability; increasing the effectiveness of the therapy and reducing side effects. In this line, the aim of this work was to produce and apply nanostructured lipid carriers (NLC) as a doxorubicin delivery system (DOXO) and its biological evaluation in bladder cancer cells. The NLC, composed by Illipe butter (solid lipid), oleic acid (oil) and Pluronic F68 stabilizer, were prepared by the hot emulsion and sonication method. The physical-chemical characterization of these NLC was performed by measured the mean hydrodynamic diameter and zeta potential (surface charge) by dynamic light scattering (DLS), crystallinity by differential scanning calorimetry (DSC), encapsulation efficiency by UV-vis spectrophotometry, cytotoxicity assay in RT4 cells and ex vivo and in vivo permeation assay of formulations applied to pig bladder by confocal microscopy. The mean hydrodynamic diameter of NLC without the drug was 103 nm and its PdI (polydispersity index) was 0.2. The encapsulation of DOXO increased the NLC diameter to 112 nm and the PdI value was 0.2. The low value of PdI indicates formulations with low polydispersion. The zeta potential values of the NLC without and with DOXO were both negative (-5 mV to -25 mV). In the thermograms of the NLC-DOXO sample the fusion peak of DOXO at 197.93 was not observed, indicating that the drug is molecularly dispersed in the lipid matrix. In the cytotoxicity assays, the NLC-DOXO formulation was more cytotoxic than free DOXO at low concentrations (31-250 ng/mL). The IC50 value was reduced 2.1 fold when DOXO was encapsulated. This increased in vitro antitumor activity may be related to increased cell uptake as confirmed by flow cytometry analysis. In the ex vivo permeation study in the pig bladder, a very similar permeation was observed between free and encapsulated DOXO. However, in the in vivo assay the encapsulated DOXO permeated more than free DOXO. The results indicates a promising release system of doxorubicin to bladder cancer therapy.
233

Low density lipoprotein as a targeted carrier for anti-tumour drugs.

January 2001 (has links)
by Lo Hoi Ka Elka. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 172-181). / Abstracts in English and Chinese. / ABSTRACT --- p.i / 摘要 --- p.iv / LIST OF TABLES AND FIGURES --- p.viii / ABBREVIATIONS --- p.xiv / Chapter CHAPTER 1 : --- INTRODUCTION / Chapter 1.1. --- DIFFERENT TREATMENTS OF THE CANCER THERAPY --- p.1 / Chapter 1.2. --- THE SIDE EFFECTS OF CANCER TREATMENT / Chapter 1.2.1. --- Surgery --- p.1 / Chapter 1.2.2. --- Radiotherapy --- p.2 / Chapter 1.2.3. --- Chemotherapy --- p.2 / Chapter 1.3. --- THE CHARACTERISTICS OF DOXORUBICIN (DOX) / Chapter 1.3.1. --- The structure of Dox --- p.6 / Chapter 1.3.2. --- The actions of Dox --- p.8 / Chapter 1.3.3. --- The adverse side effect of Dox --- p.8 / Chapter 1.4. --- THE RATIONALE OF USING LOW DENSITY LIPOPROTEIN (LDL) AS A TARGET CARRIER IN CANCER THERAPY / Chapter 1.4.1. --- The correlation between cholesterol and cancer --- p.9 / Chapter 1.4.2. --- Low density lipoprotein (LDL) as a target carrier --- p.11 / Chapter 1.4.3. --- The down and up regulation of LDL receptors --- p.14 / Chapter 1.4.4. --- The characteristics of Fuctus Craegus (FC) --- p.15 / Chapter 1.5. --- DIFFERENT METHODS OF THE PREPARATION OF THE LOW DENSITY LIPOPROTEIN-DRUG (LDL- DRUG) --- p.18 / Chapter 1.6. --- THE CHARACTERISTICS OF LOW DENSITY LIPOPROTEIN (LDL) / Chapter 1.6.1. --- The structure of LDL --- p.20 / Chapter 1.6.2. --- The metabolic pathway of LDL in human bodies --- p.23 / Chapter 1.7. --- THE MULTIDRUGS RESISTANCE IN TUMOR CELLS --- p.25 / Chapter 1.7.1. --- The mechanism of multidrug resistance --- p.27 / Chapter 1.7.2. --- The structure of P-glycoprotein --- p.27 / Chapter 1.7.3. --- The mechanism of P-glycoprotein --- p.30 / Chapter 1.8. --- COMBINED TREATMENT WITH HYPERTHERMIA --- p.31 / Chapter 1.9. --- AIM OF THE STUDY --- p.33 / Chapter CHAPTER 2 : --- MATERIALS AND METHODS / Chapter 2.1. --- MATERIALS / Chapter 2.1.1. --- Animals --- p.34 / Chapter 2.1.2. --- Buffers --- p.34 / Chapter 2.1.3. --- Cell culture reagents --- p.36 / Chapter 2.1.4. --- Chemicals --- p.38 / Chapter 2.1.5. --- Culture of cells --- p.40 / Chapter 2.2. --- METHODS / Chapter 2.2.1. --- In vitro studies / Chapter 2.2.1.1. --- "LDL, doxorubicin complex formation" --- p.41 / Chapter 2.2.1.2. --- Determination of the concentration of LDL-Dox --- p.42 / Chapter 2.2.1.3. --- In vitro cytotoxicity --- p.43 / Chapter 2.2.1.4. --- The cytotoxicity of the combined treatment with anticancer drugs --- p.44 / Chapter 2.2.1.5. --- The preparation of Fructus Crataegus (FC) --- p.46 / Chapter 2.2.1.6. --- Western blot --- p.47 / Chapter 2.2.1.7. --- Flow cytometry --- p.49 / Chapter 2.2.1.8. --- Confocal laser scanning microscopy --- p.52 / Chapter 2.2.2. --- In vivo studies / Chapter 2.2.2.1. --- Subcutaneous injection of R-HepG2 cells in nude mouse --- p.55 / Chapter 2.2.2.2. --- Treatment schedules --- p.55 / Chapter 2.2.2.3. --- Assay of investigating of the myocardial injury --- p.56 / Chapter 2.2.2.4. --- Tissue preparation procedure for light microscope (LM) --- p.57 / Chapter 2.2.3. --- Statistical analysis in our research --- p.59 / Chapter CHAPTER 3 : --- RESULTS / Chapter 3.1. --- in vitro STUDIES / Chapter 3.1.1. --- The preparation of low density lipoprotein-doxorubicin (LDL-Dox) --- p.60 / Chapter 3.1.2. --- Studies on human hepatoma cells line (HepG2 cells) / Chapter 3.1.2.1. --- The comparison of Dox and LDL-Dox accumulated in HepG2 cells --- p.63 / Chapter 3.1.2.2. --- Confocal laser scanning microscopic (CLSM) studies on the accumulation of Dox and LDL-Dox in HepG2 cells --- p.65 / Chapter 3.1.2.3. --- The comparsion of the cytotoxicity of Dox and LDL-Dox on HepG2 cells --- p.67 / Chapter 3.1.2.4. --- The comparison of the cytotoxicty of Dox and LDL-Dox with and without hyperthermia on HepG2 cells --- p.73 / Chapter 3.1.2.5. --- The comparison of accumulation of Dox and LDL-Dox in HepG2 cells treated with and without combination of with hyperthermia --- p.77 / Chapter 3.1.2.6. --- Confocal laser scanning microscopic (CLSM) studies on the accumulation of Dox and LDL-Dox in HepG2 treated cells with and without hyperthermia --- p.80 / Chapter 3.1.2.7. --- Modulation of LDL receptors on HepG2 cells------Up- regulation of LDL receptors by Fructus Craegtus (FC) / Chapter 3.1.2.7.1. --- The comparsion of LDL receptor expression on HepG2 cells after Fructus Craegtus (FC) pre-treatment --- p.83 / Chapter 3.1.2.7.2. --- The comparison of accumulation of LDL-Dox accumulated in HepG2 cells pre-treated with and without Fructus Craegtus (FC) --- p.85 / Chapter 3.1.2.7.3. --- Confocal laser scanning microscopic (CLSM) studies on the accumulation of LDL-Doxin HepG2 cells after Fructus Craegtus (FC) pre- treatment --- p.88 / Chapter 3.1.2.7.4. --- Cytotoxicity of combined treatment with LDL-Dox and Fructus Craegtus (FC) --- p.91 / Chapter 3.1.3. --- Studies on multidrug human resistant hepatoma cell line (R-HepG2 cells) / Chapter 3.1.3.1. --- The overexpression level of P-glycoprotein in resistant cell line R-HepG2 --- p.93 / Chapter 3.1.3.2. --- The comparison of Dox and LDL-Dox accumulated in R- HepG2 cells --- p.95 / Chapter 3.1.3.3. --- Confocal laser scanning microscopic (CLSM) studies on the accumulation of Dox and LDL-Dox in R-HepG2 cells --- p.97 / Chapter 3.1.3.4. --- The comparsion of the cytotoxicity of Dox and LDL-Dox on R-HepG2 cells --- p.99 / Chapter 3.1.3.5. --- The comparison of the cytotoxicty of Dox and LDL-Dox with and without hyperthermia on R-HepG2 cells --- p.109 / Chapter 3.1.3.6. --- The comparison of the accumulation of Dox and LDL- Dox in R-HepG2 cells treated in combination with hyperthermia --- p.113 / Chapter 3.1.3.7. --- Confocal laser scanning microscopic (CLSM) studies on the accumulation of Dox and LDL-Dox in R-HepG2 cells with and without hyperthermia --- p.117 / Chapter 3.1.3.8. --- Modulation of LDL receptors on R-HepG2 cells ------ Up-regulation of LDL receptors by Fructus Craegtus (FC) / Chapter 3.1.3.8.1. --- The comparsion of LDL receptor expression on R-HepG2 cells after Fructus Craegtus (FC) pre-treatment --- p.120 / Chapter 3.1.3.8.2. --- The comparsion of the accumulation of LDL- Dox in R-HepG2 cells after Fructus Craegtus (FC) pre-treatment --- p.122 / Chapter 3.1.3.8.3. --- Confocal laser scanning microscopic (CLSM) studies in the accumulation of LDL-Dox by Fructus Craegtus pre-treatment in R-HepG2 cells --- p.125 / Chapter 3.1.3.8.4. --- The comparison of cytotoxicity of combined treatment with LDL-Dox and Fructus Craegtus (FC) in R-HepG2 cells --- p.128 / Chapter 3.2. --- in vivo STUDIES / Chapter 3.2.1. --- The comparison of Dox and LDL-Dox on reducing the tumor sizes and weight in nude mice bearing R-HepG2 cells / Chapter 3.2.1.1. --- The comparison of Dox and LDL-Dox on reducing the tumor size in nude mice bearing R-HepG2 cells --- p.130 / Chapter 3.2.1.2. --- The comparison of Dox and LDL-Dox on reducing the tumor weight in nude mice bearing R-HepG2 cells --- p.138 / Chapter 3.2.2. --- Myocardial injury measured by Lactate dehydrogenase (LDH) activity in nude mice bearing R-HepG2 cells treated with Dox and LDL-Dox --- p.140 / Chapter 3.2.3. --- Myocardial injury measured by Creatine kinase (CK) activity in nude mice bearing R-HepG2 cells treated with Dox and LDL-Dox --- p.143 / Chapter 3.2.4. --- Histological studies of heart of nude mice bearing R-HepG2 cells treated with Dox and LDL-Dox / Chapter 3.2.4.1. --- Heart section of nude mice --- p.146 / Chapter 3.2.4.2. --- Heart section of nude mice bearing R-HepG2 cells --- p.148 / Chapter 3.2.4.3. --- Heart section of lmg/kg Dox treated nude mice bearing R- HepG2 cells --- p.150 / Chapter 3.2.4.4. --- Heart section of 2mg/kg Dox treated nude mice bearing R- HepG2 cells --- p.152 / Chapter 3.2.4.5. --- Heart section of lmg/kg LDL-Dox treated nude mice bearing R-HepG2 cells --- p.154 / Chapter CHAPTER 4 --- : DISCUSSION / Chapter 4.1. --- in vitro STUDIES / Chapter 4.1.1. --- The cytotoxicity of Dox and LDL-Dox on HepG2 cells and R- HepG2 cells --- p.156 / Chapter 4.1.2. --- The combined treatment on HepG2 cells and R-HepG2 cells --- p.157 / Chapter 4.1.3. --- The modulation of LDL-R expression --- p.159 / Chapter 4.2. --- in vivo STUDIES --- p.162 / Chapter CHAPTER 5 --- : CONCLUSION / Chapter 5.1. --- CONCLUSION / Chapter 5.1.1. --- In vitro studies --- p.167 / Chapter 5.1.2. --- In vivo studies --- p.169 / Chapter 5.2. --- FUTURE PROSPECTIVE --- p.170 / REFERENCES --- p.172
234

A solution to the inherent list on Nimitz class aircraft carriers

Wolfson, Dianna January 2004 (has links)
Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2004. / Includes bibliographical references (p. 53). / Nimitz class aircraft carriers possess an inherent list to starboard that their list control systems (LCS) are typically unable to correct while under Combat Load Conditions. As a result, it has become necessary to use fresh water ballast in a number of inner bottom voids and damage control voids to augment the LCS. Maintaining liquid ballast in damage control voids is unacceptable, as it reduces the design counter flooding capability of the ship, and thus reduces ship survivability. In order to restore the ships operational flexibility and achieve the necessary/desired list correction, this study determines the effect of adding solid ballast to a series of voids/tanks identified on the 2nd, 4th, and 8th decks. Based on ballast density, tank location and capacity, ease of ballast installation, minor tank structural modifications, and a decision making cost analysis, solid ballast was determined to be the most advantageous for use in correcting the inherent list on the Nimitz class aircraft carriers. Fresh water ballast was also examined as a possible alternative, but not as extensively due to the large quantity of water required and its limited ability to achieve a list correction. Nimitz class aircraft carriers currently have an average list of 1.5 degrees and a KG of 47 feet. / (cont.) Since their allowable KG cannot exceed 48.5 feet, the average service life allowance (SLA) for KG is approximately 1.5 feet. This study shows that by adding approximately 400 Iton of solid ballast, list can be corrected by 1.5 degrees with only a 0.1 percent increase in KG. Thus, to permanently fix the average Nimitz class aircraft carrier starboard list, there would be a 0.05 foot increase in KG, which in all cases is within the SLA. Additionally, this study shows that this 1.5 degree list correction can be accomplished at a low cost of approximately $1,200 per Iton. Considering the reduction in operational constraints and the benefits to ship survivability, this is truly an inexpensive proposition. / by Dianna Wolfson. / S.M. / Nav.E.
235

Estudo in vitro do efeito da ativação do Sistema Complemento na estabilidade de lipossomas de diferentes composições: seleção do melhor sistema de liberação e sua avaliação como carreador de flavonoides / In vitro study of the effect of the activation of complement system in the stability of different liposomes compositions: selection of the best delivery system and its evaluation as a flavonoid carrier

Chrysostomo, Taís Nader 31 October 2011 (has links)
Lipossomas (LUV) são estruturas compostas por uma bicamada lipídica que se organizam de forma semelhante a vesículas, contendo um compartimento aquoso em seu interior. Têm sido avaliados como potenciais carreadores de fármacos. No entanto, após sua administração, in vivo, opsoninas do soro adsorvem-se em sua superfície contribuindo para que o sistema fagocitário mononuclear (SFM) reconheça essas partículas, favorecendo sua remoção da circulação. O sistema complemento (SC) parece ter papel importante neste processo, principalmente por gerar fragmentos ativos do componente C3 (C3b/iC3b) que se depositam nas vesículas lipossomais e são reconhecidos por receptores do complemento presentes, por exemplo, nos polimorfonucleares. Antioxidantes, como a quercetina, têm demonstrado importantes e benéficos efeitos sobre a saúde humana, porém sua baixa solubilidade em água e biodisponibilidade limitam seu uso. Assim, o desenvolvimento apropriado de carreadores de flavonoides seria de grande importância para sua aplicabilidade in vivo. O objetivo do presente trabalho é avaliar a ativação das proteínas do SC por lipossomas compostos de fosfatidilcolina de soja e colesterol (PC:CHOL) ou colesteril-etil-éter (PC:CHOL-OET), contendo ou não quercetina. O consumo das vias clássica (VC) e alternativa (VA) provocado pelas diferentes vesículas foi analisado por ensaio hemolítico e a quantificação de iC3b e anticorpos naturais (IgG e IgM) na superfície dessas partículas foi realizada através de kits de ELISA. A ativação de C3 por vesículas contendo ou não quercetina foi avaliada por imunoeletroforese bidimensional (IEF). Os resultados mostram que lipossomas vazios, compostos por grande quantidade de colesterol, consomem mais os componentes do complemento para ambas as vias, VC e VA. Ainda, a substituição de colesterol por colesteril-etil éter reduziu o consumo das duas vias, mas a ativação do SC ainda é dependente da quantidade deste composto. A incorporação de quercetina não alterou o consumo de ambas as vias. O depósito de iC3b, IgG ou IgM nas vesículas compostas de PC:CHOL-OET na proporção de massa 3:1 foi o menor comparado aos demais. A IEF mostrou que vesículas PC:CHOL vazias induzem maior clivagem de C3 em relação às vesículas PC:CHOL-OET. Ainda, a incorporação de quercetina reduz a conversão de C3 em seus fragmentos. Essas observações sugerem que a preparação lipossomal PC:CHOL-OET em proporção de massa 3:1 parece ser a mais adequada para dar continuidade aos estudos que deverão culminar na tentativa de utilizá-la como carreadora de quercetina para administração in vivo / Liposomes (LUV) are structures composed by lipid bilayer that are organized similarly to vesicles, containing an aqueous compartment inside. They have been evaluated as potential drug carriers, however, after in vivo administration, serum opsonins are adsorb on the surface, contributing to their clearance from the circulation by mononuclear phagocytes system (MPS). The complement system (CS) seems to play an important role in this process, mainly to generate active fragments of the C3 component (C3b/iC3b) that are deposited in the liposomal vesicles and are recognized by complement receptors present, for example, in polymorphonuclear cells. Antioxidants such as quercetin have demonstrated significant and beneficial effects on human health, but its low water solubility and bioavailability limit their use. Thus, the proper development of flavonoids carriers would be of great importance to its applicability in vivo. The objective of this study is to evaluate the activation of SC proteins by liposomes composed of soy phosphatidylcholine and cholesterol (PC: CHOL) or cholesteryl ethyl ether (PC: CHOL-OET), with or without quercetin. The consumption of the classical (CP) and alternative pathway (AP) caused by the different vesicles was analyzed by hemolytic assay and quantification of iC3b and natural antibodies (IgG and IgM) on the surface of these particles was performed using ELISA kits. The activation of C3 by vesicles with or without quercetin was assessed by two-dimensional immunoelectrophoresis (IEF). The results show that empty liposomes, composed of large amounts of cholesterol, consume more CS components in both pathways, CP and AP. Moreover the replacement of cholesterol by cholesteryl ethyl ether reduced the consumption of both pathways, but the activation of the SC is still dependent on the amount of the compound. The incorporation of quercetin did not alter the consumption of both pathways. The deposition of iC3b, IgG or IgM in vesicles composed of PC: CHOL-OET at mass ratio of 3:1 was the lowest compared to the others. The IEF showed that empty vesicles of PC:CHOL induce less cleavage of C3 in relation to vesicles of PC: CHOL-OET. In addition, the incorporation of quercetin reduces the conversion of C3 into its fragments. These observation suggest that the liposomes PC:CHOL at mass ratio 3:1 seems to be the most appropriate to continue the studies that could culminate in an attempt to use it as a carrier to administrate quercetin in vivo
236

Formulation of polymer-stabilized doxorubicin nanoparticles by flash nanoprecipitation for improved uptake into cancer cells.

January 2013 (has links)
ABC運輸蛋白的過度表達是多重抗藥性(MDR)的重要機制之一,癌細胞會同時對結構上無關的抗癌藥物產生抗藥性。避免癌細胞的多重抗藥性有不同方法,其中用聚合物納米載體來攜帶易受多重抗藥性影響的抗癌藥物近年來獲得了很大的關注。本研究的目標在使用一個相對新穎的納米開發技術,被稱為瞬時納米沉澱(FNP),去開發一種運載著易受多重抗藥性影響的抗癌藥物的聚合物納米粒子系統。為此,我們使用專門設計的四流多進旋渦混合器(MIVM),把阿黴素(DOX),一種屬於蒽環類的抗癌藥物,亦同時作為P糖蛋白(P-gp)底物的藥物,包進在二嵌段共聚物內。 / 目的:本研究的目的是:(一)通過MIVM,利用瞬時納米沉澱去配製運載DOX的聚合物納米粒子;(二)辨别和優化納米粒子的大小,物理性能和運載DOX聚合物納米粒子的體外釋放速率;(三)檢查納米粒子的表面元素和化學組成;(四)評估優化納米粒子在抗藥性癌症細胞模型的抗腫瘤能力和抵抗多重抗藥性的能力。 / 方法:不同藥物(DOX)對聚合物比例的瞬時納米沉澱是通過在四流MIVM中混合溶在有機溶液二甲基甲酰胺(DMF)或二甲基酮(ACT)的鹽酸阿黴素(DOX.HC1)或阿黴素游離鹼(DOX.FB)和兩親性二嵌段共聚物[聚乙二醇-聚乳酸;分子量2000-10000]和反抗溶劑(含有氫氧化鈉為DOX.HCl或純淨水DOX+FB)來製備的。納米混懸劑的平均粒徑和粒度分佈會通過動態光散射粒度分析法去檢測,表面電荷會通過界達電位測量去檢測。阿黴素的包封率和載藥量會用紫外/可見光譜儀在波長為480 nm時測定。粒子形態將會用原子力顯微鏡(AFM)來去檢測,粒子表面的組合物將會用X-射線光電子能譜(XPS)來去檢測DOX聚合物納米粒子在不同pH值的的體外釋放會通過紫外/可見光譜儀去檢測。DOX聚合物納米粒子的體外細胞毒性會利用橫若丹明B比色法檢定,藥物積累和反轉運會利用流式細胞儀分析來測定。 / 結果:在適當優化鹽酸阿黴素(DOX.HC1)或阿黴素游離鹼(DOX.FB)的聚合物的比例後,我們成功製備了平均粒徑小於100 nm的DOX聚合物納米粒子(DOX.NP)與使用在有機溶液中DOX.HC1和水相的氫氧化鈉中和法相比,通過在有機溶液中的DOX.FB和純水作為反溶劑來製備的DOX.NP表現出類似的平均粒子大小(小於100 nm),但顯示出更高的藥物包封率(48 %, 而不是中和法的25 %)。用DOX.FB製備的DOX.NP的載藥量可達14 %DOX.NP表現出pH依賴性的藥物釋放曲線,和在酸性pH值時更强的累積釋放率。X-射線光電子能譜顯示沒有阿黴素出現在納米粒子的表面上P-gp過度表達的LCC6抗藥性乳腺癌细胞的細胞毒性作用顯示了 DOX.NP和DOX.HC1在缓衝溶液中的差異並不顯著。相對DOX.HC1,流式細胞儀分析確定了 DOX.NP明顯增加了細胞攝取DOX的能力。此外,在外排後,DOX.NP在細胞內DOX的濃度顯示出了更長的保留時間。 / 結論:一種通過在多進旋過混合器(MIVM)進行反溶劑沉澱,用於配製具有可控的粒子大小運載DOX的聚合物納米粒子的快速,方便,和可重複性的方法已經被開發。配製的納米粒子顯示出pH值依賴性持續的藥物釋放曲線和更強的癌細胞攝取DOX能力。 / Over-expression of ATP-binding cassette (ABC) is one of the most important mechanisms responsible for multidrug resistance (MDR), in which tumor cells exhibit simultaneous resistance to structurally unrelated anticancer drugs. Various approaches have been attempted to circumvent MDR in cancer cells, among which polymeric nanocarrier for delivery of MDR-sensitive anticancer drugs has received considerable attention in recent years. The present project was aimed at developing a polymeric nanoparticle system using a relatively novel nanoparticle technology termed flash nanoprecipitation (FNP) for delivery of MDR-susceptible chemotherapeutic agents. To this end, doxorubicin (DOX), an anthracycline anticancer agent and a P-gp substrate, was incorporated into an amphiphilic diblock copolymer using a specially designed four-stream multi-inlet vortex mixer (MIVM). / PURPOSES: The objectives of the present study are: (a) to formulate DOX-loaded polymeric nanoparticles by FNP using an MIVM; (b) to characterize and optimize the particle size, physical properties and in vitro DOX release rate of the formulated nanoparticles; (c) to examine the surface elemental and chemical compositions of the formulated nanoparticles; (d) to evaluate the anti-tumor activity of the optimized nanoparticles and their ability to combat MDR in resistant cancer cell line models. / METHODS: FNP of DOX was effected in a four-stream MIVM by mixing organic solutions of doxorubicin hydrochloride (DOX.HCl) or doxorubicin free base (DOX.FB) and an amphiphilic diblock copolymer [polyethylene glycol-polylactic acid (PEG-PLA); MW2k-10 ki]n dimethylformamide (DMF) or acetone (ACT) at different drug-to-polymer ratios with an antisolvent (water containing sodium hydroxide for DOX.HCl or pure water for DOX.FB). The resulting nanosuspensions were characterized for mean particle size and size distribution by dynamic light scattering particle size analysis; surface charges by zeta potential measurements; drug encapsulation efficiency and drug loading by UV/visible spectroscopy at 480 nm; particle morphology by atomic force microscopy (AFM); and surface composition by x-ray photoelectron spectroscopy (XPS). In vitro DOX release from the nanoparticles was measured at different pHs by UV/visible spectroscopy. In vitro cytotoxicity was evaluated by Sulforhodamine B colorimetric assay, and drug accumulation and efflux were determined by flow cytometric analysis. / RESULTS: DOX-loaded polymeric nanoparticles (DOX.NP) with mean particle size below 100 nm were obtained after appropriate optimization of the DOX.HCl or DOX.FB to polymer ratio. Compared with the neutralization method using DOX.HCl in the organic phase and sodium hydroxide in the aqueous phase, DOX.NP prepared with DOX.FB in the organic phase and pure water as antisolvent exhibited a similar mean particle size (< 100 nm) but a significantly higher drug encapsulation efficiency (48% as opposed to 25% for the neutralization method). Drug loading of DOX.NP prepared with DOX.FB could reach up to 14%. DOX.NP exhibited a pH-dependent drug release profile with a much higher cumulative release rate at acidic pHs. XPS revealed that no DOX was present on the nanoparticle surface. The cytotoxic effect on P-gp over-expressing LCC6/MDR cell line revealed insignificant differences between DOX.NP and DOX.HCl in buffered aqueous media. DOX.NP exhibited a marked increase in DOX cellular uptake relative to free DOX, as determined by flow cytometric analysis. Furthermore, DOX.NP showed a significant retention of intracellular concentration of DOX after efflux. / CONCLUSION: A rapid, convenient, and reproducible method for generating DOX-loaded polymeric nanoparticles with controllable particle size through antisolvent precipitation in a multi-inlet vortex mixer has been developed. The formulated nanoparticles displayed a pH-dependent sustained drug release profile and an enhanced DOX uptake into cancer cells. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Tam, Yu Tong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 119-130). / Abstracts also in Chinese. / ABSTRACT --- p.i / 摘要 --- p.iv / ACKNOWLEDGEMENTS --- p.vi / TABLE OF CONTENTS --- p.vii / LIST OF FIGURES --- p.x / LIST OF TABLES --- p.xiii / ABBREVIATIONS --- p.xv / Chapter CHAPTER 1. --- Introduction --- p.1 / Chapter 1.1 --- Rationale of the Study --- p.2 / Chapter 1.2 --- Doxorubicin --- p.3 / Chapter 1.2.1 --- Origin --- p.3 / Chapter 1.2.2 --- Physico-chemical properties --- p.6 / Chapter 1.2.3 --- Mechanism of Action --- p.7 / Chapter 1.2.4 --- Multidrug Resistance in Cancer --- p.7 / Chapter 1.2.4.1 --- Mechanisms of Multidrug Resistance --- p.8 / Chapter 1.3 --- Nanoparticles for Cancer Therapy --- p.9 / Chapter 1.3.1 --- Properties of Nanoparticles --- p.9 / Chapter 1.3.1.1 --- Small Particle Size --- p.10 / Chapter 1.3.1.2 --- High Payload Density --- p.11 / Chapter 1.3.1.3 --- Flexible Modification of Surface Properties --- p.11 / Chapter 1.3.2 --- Targeted Cancer Therapy --- p.12 / Chapter 1.3.2.1 --- Passive Tumor Targeting --- p.13 / Chapter 1.3.2.2 --- Active Tumor Targeting --- p.14 / Chapter 1.3.3 --- Reversal of Multidrug Resistance --- p.15 / Chapter 1.3.3.1 --- Endocytosis of Nanoparticles --- p.16 / Chapter 1.3.4 --- Nanoparticle Approaches to Anti-cancer Drug Delivery --- p.17 / Chapter 1.3.4.1 --- Liposomes --- p.18 / Chapter 1.3.4.2 --- Polymeric Nanoparticles --- p.18 / Chapter 1.4 --- Fabrication of Nanoparticles --- p.19 / Chapter 1.5 --- Aims and Scope of the Present Study --- p.21 / Chapter CHAPTER 2. --- Materials & Methods --- p.23 / Chapter 2.1 --- Materials --- p.24 / Chapter 2.1.1 --- Chemicals --- p.24 / Chapter 2.1.2 --- Materials for Cell Culture --- p.25 / Chapter 2.2 --- Methods --- p.26 / Chapter 2.2.1 --- Preparation of Doxorubicin Nanoparticles by Flash Nanoprecipitation --- p.26 / Chapter 2.2.1.1 --- Acid-Base Neutralization during Mixing --- p.26 / Chapter 2.2.1.2 --- Preparation of Doxorubicin Free Base before Mixing --- p.29 / Chapter 2.2.1.2.1 --- Doxorubicin Free Base Preparation --- p.29 / Chapter 2.2.2 --- Determination of Particle Size and Zeta Potential --- p.30 / Chapter 2.2.3 --- Co-stabilizers and Particle Stability --- p.30 / Chapter 2.2.4 --- Chemical Stability of Doxorubicin --- p.31 / Chapter 2.2.5 --- Determination of Encapsulation Efficiency --- p.31 / Chapter 2.2.5.1 --- Calibration Curve of Doxorubicin --- p.33 / Chapter 2.2.5.2 --- Dialysis --- p.33 / Chapter 2.2.5.3 --- Ultrafiltration --- p.35 / Chapter 2.2.6 --- Determination of Drug Loading --- p.35 / Chapter 2.2.6.1 --- Freeze Drying --- p.36 / Chapter 2.2.7 --- Morphological Examination --- p.36 / Chapter 2.2.7.1 --- X-ray Photoelectron Spectroscopy --- p.36 / Chapter 2.2.7.2 --- Atomic Force Microscopy --- p.36 / Chapter 2.2.8 --- In vitro release study --- p.37 / Chapter 2.2.8.1 --- Experimental Protocols --- p.37 / Chapter 2.2.8.2 --- Calculation of Cumulative Drug Release --- p.37 / Chapter 2.2.9 --- In vitro cytotoxicity study --- p.38 / Chapter 2.2.9.1 --- Sulforhodamine B Colorimetric Assay --- p.38 / Chapter 2.2.10 --- Cellular Uptake study --- p.39 / Chapter 2.2.10.1 --- Drug Accumulation Assay --- p.39 / Chapter 2.2.10.1 --- Drug Efflux Assay --- p.39 / Chapter 2.2.11 --- Analytical techniques --- p.40 / Chapter 2.2.11.1 --- UV/Vis Analysis --- p.40 / Chapter 2.2.11.2 --- HPLC Analysis --- p.40 / Chapter 2.2.12 --- Statistical analysis --- p.41 / Chapter CHAPTER 3. --- Results & Discussions --- p.42 / Chapter 3.1 --- Preparation of Doxorubicin Nanoparticles by Flash Nanoprecipitation --- p.43 / Chapter 3.1.1 --- Acid-Base Neutralization during Mixing --- p.44 / Chapter 3.1.1.1 --- Influence of Drug Concentration --- p.44 / Chapter 3.1.1.2 --- Influence of Alkaline Medium --- p.48 / Chapter 3.1.1.3 --- Influence of Drug-to-Polymer Ratios --- p.53 / Chapter 3.1.1.4 --- Particle Stability --- p.54 / Chapter 3.1.1.5 --- Co-stabilizers Tests on Stability --- p.55 / Chapter 3.1.1.5.1 --- Effect of PEG-PLA Co-polymers --- p.55 / Chapter 3.1.1.5.2 --- Effect of Co-stabilizers --- p.56 / Chapter 3.1.2 --- Preparation of Doxorubicin Free Base before Mixing --- p.62 / Chapter 3.1.2.1 --- Influence of Solvent System --- p.62 / Chapter 3.1.2.2 --- Influence of Drug-to-Polymer Ratios --- p.65 / Chapter 3.1.2.3 --- Drug Loading --- p.65 / Chapter 3.1.2.4 --- Particle Stability --- p.68 / Chapter 3.1.2.4.1 --- Concentrated Particle Stability --- p.73 / Chapter 3.2 --- Stability Studies on Doxorubicin Nanoparticle at Physiological and Cancer Cell pHs --- p.75 / Chapter 3.2.1 --- Chemical Stability --- p.75 / Chapter 3.2.2 --- Physical Stability --- p.77 / Chapter 3.3 --- In vitro Release Study --- p.79 / Chapter 3.4 --- Morphological Examination --- p.86 / Chapter 3.4.1 --- Zeta Potential --- p.92 / Chapter 3.5 --- In vitro Cellular Study --- p.93 / Chapter 3.5.1 --- Cellular Uptake Study --- p.93 / Chapter 3.5.1.1 --- Drug Accumulation and Drug Efflux --- p.93 / Chapter 3.5.2 --- Cytotoxicity of Blank Nanoparticles --- p.98 / Chapter 3.5.3 --- Cytotoxicity of DOX loaded Nanoparticles --- p.100 / Chapter CHAPTER 4. --- Conclusions --- p.106 / APPENDIX --- p.109 / REFERENCES --- p.118
237

The influence of climate and socio-ecological factors on invasive mosquito vectors in the Northeastern US: Assessing risk of local arboviral transmission

Little, Eliza Anastazia Hazel January 2017 (has links)
Background: Mosquito-borne diseases are a growing concern for temperate regions including the northeastern US. There the two primary mosquito vectors, Cx. pipiens and Ae. albopictus are widespread, endemic circulation of West Nile virus causes sporadic outbreaks, and imported arboviruses such as dengue, chikungunya, and Zika are on the rise. With temperate mosquito-borne disease outbreaks likely to increase in frequency, it is critical to reduce mosquito populations in the northeastern US. Community-based source reduction is heralded as the most sustainable component of integrated mosquito management. Yet mosquitoes develop rapidly, requiring weekly maintenance of mosquito habitat. This is onerous and community commitment flags. The development of predictive models to inform focused vector-control efforts is therefore of great utility. Objectives and Methods: The overarching objective of this research is to make robust predictive modeling frameworks based on empirically derived relationships of the ecology and epidemiology of mosquito-borne disease systems in the northeastern US. We aim to quantify the relationships between local environmental and meteorological conditions and mosquito vectors. In Chapters 2 and 4 we use lengthy surveillance records to develop models and use model ensembles to generate predictions based on out-of-sample data. For chapter 3 we use more spatially refined data to investigate the influence of intra-urban heterogeneities and how climatic conditions influence mosquito populations across these defined differences. Results: In Chapter 2, we model and forecast WNV infection rates among mosquito vectors using meteorological and hydrological conditions. We show that real-time climate information can predict WNV Culex infection rates prior to when human risk is greatest. In Chapter 3, we link infrastructure degradation and vegetation patterns with Ae. albopictus infestation levels as well as the interactive effect of precipitation across these environmental conditions. In Chapter 4, we identify key land use characteristics and meteorological conditions associated with annual Ae. albopictus abundance. Further we use imported chikungunya cases to delineate areas of high arboviral importation and, in combination with areas of high Ae. albopictus abundance, areas at heightened risk for arboviral transmission. Conclusions: While temperate outbreaks are often self-limiting they may be increasing in frequency and severity. Due to the multitude of invasive vectors and arboviruses, vector control techniques that work for multiple mosquito species are likely more effective and sustainable. Here we build build empirical models that accurately predict mosquito dynamics before populations peak which is critical for vector control. We recommend integrating predictive modeling into mosquito management guidelines as this could focus valuable resources to when and where mosquito-borne transmission risk is greatest. Further we find social and ecological determinants of mosquito dynamics, supporting further study that combine socio-ecological processes into model frameworks.
238

Síntese, caracterização e estudos em solução de terpolímeros antififílicos termo-sensíveis ao pH: uma perspectiva para obtenção de sistemas transportadores de fármacos

Blaz Vieira, Neide Aparecida [UNESP] 17 February 2006 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:30:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-02-17Bitstream added on 2014-06-13T21:01:34Z : No. of bitstreams: 1 blazvieira_na_dr_sjrp.pdf: 2164319 bytes, checksum: f4c71268208cbd270c732d15862f8233 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A presente tese envolveu a síntese e caracterização de duas séries de polímeros anfifílicos inteligentes. A utilização de quatro monômeros foi feita com o objetivo de se conferir aos polímeros sensibilidade à temperatura e ao pH . Na primeira série, ou série 1, foram sintetizados terpolímeros anfifílicos termo-sensíveis a partir dos monômeros Nisopropilacrilamida (NIPAm), monometacrilato de poli(etilenoglicol)metil éter (PEG) e ndodecilmetacrilato (DOMA), cuja termo-sensibilidade foi controlada variando-se a proporção molar dos monômeros. Os polímeros foram caracterizados utilizando-se as técnicas de ressonância magnética nuclear e cromatografia de permeação em gel (GPC). As propriedades das soluções foram estudadas empregando-se espectrofotometria, fluorescência e espalhamento de luz dinâmico. Os polímeros exibiram temperatura de turvação em solução aquosa entre 17 e 52ºC, dependendo da composição. A proporção do monômero hidrofílico (PEG) foi variada com o objetivo de se obter termo-sensibilidade próxima à temperatura do corpo humano (37° C). O aumento da força iônica das soluções pela adição de KCl reduziu a temperatura de turvação pelo efeito salting out. Os polímeros formaram, em solução aquosa, microdomínios hidrofóbicos, cuja CAC variou de 1,2x10-3 a 1x10-2 g dm-3 , com o aumento da proporção molar de PEG de 5 a 35%. Os agregados hidrofóbicos tipo micelar apresentaram um tamanho que variou de 50 a 140 nm, dependendo da proporção dos monômeros, e mostraram capacidade para incorporar moléculas hidrofóbicas, como pireno e doxorubicina. As quantidades máximas incorporadas foram de, respectivamente, 6,1 mg/g polímero e 13,5 mg/g polímero para pireno e doxorubicina. Agregados mais hidrofóbicos incorporaram uma quantidade maior do hidrófobo. / In the present thesis the synthesis and characterization of two series of intelligent polymers were performed aiming to construct potential drug carriers. Four monomers were employed to provide thermo and pH sensitivity to the systems. In the first series terpolymers of N-isopropylacrylamide, dodecyl methacrylate (DOMA) and poly(ethylene glycol)(PEG) methacrylate, were synthesized by random copolymerization, and the composition was controlled to achieve systems having different thermosensitivities. 1HNMR spectra and gel permeation chromatography (GPC) were employed to characterize the different samples obtained. The solution properties were studied by employing spectrophotometry, fluorescence, and dynamic light scattering techniques. The chemical compositions in the final terpolymers are close to those in the feed and the composition was controlled aiming to adjust the thermosensitivity close to that of the human body temperature (370C). The polymers exhibited cloud point temperatures (Tcs) varying from 17 to 52 0C. Micropolarity studies using I1/I3 ratio of the vibronic bands of pyrene show the formation of amphiphilic aggregates capable of incorporating hydrophobic drugs as the polymer concentration is increased. The critical aggregation concentration (CAC) increases from 1.2x10-3 to 1x10-2 g.L-1 with the PEG content varying from 5 to 35 mol%. Anisotropy measurements confirm the results obtained by pyrene fluorescence and show that the aggregates resulting from intermolecular interactions present different organizations. The hydrodynamic diameters (Dh) of the aggregates determined by dynamic light scattering (DLS) vary from 40 to 150 nm depending on the terpolymer composition. The Tcs and Dh values decreased with the ionic strength, and this behavior was attributed to the dehydration of the polymeric micelles. The capacity of solubilization of the aggregates was evaluated by employing pyrene and adryamicin and the obtained results confirm th
239

Avalia??o da fixa??o biol?gica de nitrog?nio em plantios tecnificados de feij?o-caupi na regi?o Centro-Oeste do Brasil / Evaluation of biological nitrogen fixation in technified crops of cowpea in the Midwest region of Brazil

SILVA J?NIOR, Elson Barbosa da 24 February 2012 (has links)
Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-08-17T19:59:36Z No. of bitstreams: 1 2012 - Elson Barbosa da Silva Junior.pdf: 1890259 bytes, checksum: 16078598a033a11572fd35aadc93d40b (MD5) / Made available in DSpace on 2017-08-17T19:59:36Z (GMT). No. of bitstreams: 1 2012 - Elson Barbosa da Silva Junior.pdf: 1890259 bytes, checksum: 16078598a033a11572fd35aadc93d40b (MD5) Previous issue date: 2012-02-24 / CAPES / The planting of cowpea [Vigna unguiculata (L.) Walp.] is growing in the Midwest of Brazil, which is characterized by a technified agriculture, with an average yield of 1000 kg ha-?. New technologies of inoculation as carriers and the agricultural practice of pre inoculation are presented as alternative to current technologies. Thus the objective of this study was to evaluate technologies for cowpea inoculation in the Midwest region of Brazil. The quality of the polymeric IPC 2.2 inoculant was evaluated for the cells survival at 180 days of storage and the ability to maintain viable cells after five weeks of inoculation. The agronomic performance of the polymeric inoculant and the pre inoculation were compared with technologies already recommended, in three different experiments with the same cultivate (BRS Guariba) in areas of Embrapa Agrobiologia (Serop?dica-RJ), Embrapa Agrossilvipastoril (Sinop-MT) and in the New Horizon farm ? Seeds Tomazetti (Primavera do Leste, MT). The contribution of biological nitrogen fixation was quantified by 15N natural abundance delta (?) in the two experiments in Mato Grosso State. In the experiment at Embrapa Agrobiologia the polymeric inoculant IPC 2.2 was compared with peat and liquid carriers, plus nitrogen treatments with 50 and 80 kg N ha-? and the absolute treatment. In the experiment at Embrapa Agrossilvopastoril the treatments were pre inoculated with polymeric inoculant IPC 2.2 and peat carrier, with 0, 1, 2 and 5 weeks before planting for both inoculants plus addition of nitrogen (70 kg N ha-?), and the absolute treatment. The assay at the New Horizon farm was in a central pivot area of 60 ha with the strains: BR3267 in the polymeric and liquid carriers; BR3262 in polymeric; and a consortium of four recommended strains (BR3267, BR3262, and BR3301 BR3302) in the polymeric carrier. The polymer showed inoculant cell concentration higher than 109 cells per gram after 180 days, and in the field experiment the formulation IPC 2.2 provided yield above the reference treatment and equal to the N treatment, and the peat and liquid carriers. The pre-inoculation with the polymeric blend with five weeks had the highest nodule dry mass, however it did not differ from the N control and the absolute, and the treatments did not differ for the productivity. In the essay at the Novo Horizonte farm the inoculation with the consortium of four strains had the highest nodule dry mass, and it differed from the BR3267 in liquid carrier and the BR3262. The contribution of biological nitrogen fixation did not exceed 50%, and the highest averages were obtained with 48% and 39% of N originated from biological fixation, respectively in the pre inoculation essay (14 days in the peat carrier), and with the BR3262 at the New Horizon farm with the polymeric carrier. Thus, it is concluded that the polymer inoculant might be recommended for the traditional form inoculation of the cowpea crop, and inoculation should be a common practice, since it was proven that with the no inoculated seeds there was no biological nitrogen fixation. / O plantio de feij?o-caupi [Vigna unguiculata (L.) Walp.] vem crescendo no Centro-Oeste do Brasil, que se caracteriza por uma agricultura tecnificada, com m?dia de produtividade de 1000 kg ha-?. Novas tecnologias de inocula??o, como ve?culos e uma pr?tica agr?cola de pr? inocula??o apresentam-se como alternativa as tecnologias atuais. Assim o objetivo deste trabalho foi avaliar tecnologias de inocula??o de feij?o-caupi na regi?o Centro-Oeste do Brasil. Foi avaliada a qualidade do inoculante polim?rico IPC 2.2, quanto ? sobreviv?ncia de c?lulas aos 180 dias de armazenamento e quanto ? capacidade de manter c?lulas vi?veis ap?s cinco semanas de inocula??o. O desempenho agron?mico do inoculante polim?rico e da pr? inocula??o foi comparado com as tecnologias j? recomendadas em tr?s experimentos distintos com a mesma cultivar BRS Guariba nas ?reas da Embrapa Agrobiologia (Serop?dica-RJ), Embrapa Agrossilvipastoril (Sinop-MT) e na fazenda Novo Horizonte- Sementes Tomazetti ( Primavera do Leste-MT). Foi quantificada a contribui??o da fixa??o biol?gica de nitrog?nio pela abund?ncia natural do delta 15N (?) nos dois experimentos no Mato Grosso. No experimento na Embrapa Agrobiologia o inoculante polim?rico IPC 2.2 foi comparado com os ve?culos turfoso e l?quido, mais os tratamentos nitrogenados com 50 e 80 kg N ha-? e o absoluto. No experimento na Embrapa Agrossilvipastoril os tratamentos foram pr? inoculados com inoculante polim?rico IPC 2.2 e turfoso com 0, 1, 2 e 5 semanas antes do plantio para ambos inoculantes, mais o tratamento nitrogenado (70 kg N ha-?) e o absoluto. O ensaio na fazenda Novo Horizonte foi em ?rea de piv? central de 60 ha, com as estirpes: BR3267 em ve?culo polim?rico e l?quido; BR3262 em ve?culo polim?rico; e o cons?rcio das quatro estirpes recomendadas (BR3267, BR3262, BR3301 e BR3302) em ve?culo polim?rico. A formula??o IPC 2.2 manteve concentra??o de c?lulas superior a 109 c?lulas por grama ap?s 180 dias e no campo ela proporcionou uma produtividade superior ao tratamento absoluto e igual a dos tratamentos nitrogenados, ve?culos turfoso e l?quido. A pr?-inocula??o com a mistura polim?rica com cinco semanas obteve a maior massa de n?dulos secos, por?m n?o diferiu do controle nitrogenado e absoluto, assim como na produtividade os tratamentos n?o diferiram entre si. No ensaio na fazenda Novo Horizonte a inocula??o com o cons?rcio das quatro estirpes obteve a maior massa de n?dulos secos e diferiu da BR3267 em ve?culo l?quido e da BR3262. A contribui??o da fixa??o biol?gica de nitrog?nio n?o ultrapassou os 50%, obtidas as maiores m?dias com 48% e 39% do N oriundo da fixa??o biol?gica respectivamente nos ensaios de pr?-inocula??o (14 dias no ve?culo turfa) e com a BR3262, na fazenda Novo Horizonte e em ve?culo polim?rico. Assim, se conclui que o inoculante polim?rico pode ser recomendado para inocula??o tradicional do feij?o caupi e que a inocula??o da cultura deve ser uma pr?tica corriqueira, uma vez que foi comprovado que com sementes n?o inoculadas n?o houve fixa??o biol?gica de nitrog?nio.
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Comparative phylogenetic exploration of the human mitochondrial proteome : insights into disease and metabolism

Smith, Cassandra Lauren January 2019 (has links)
Mitochondria are a key organelle within human cells, with functions ranging from ATP synthesis to apoptosis. Changes in mitochondrial function are associated with many diseases, as well as 'natural' processes like ageing. Mitochondria have a unique evolutionary origin, as the result of an endosymbiotic relationship between a bacterium and an archaeal cell. Therefore, the phylogenetic history of the mitochondrial proteome is also unique within the total human proteome. A new description of the genes encoding the human mitochondrial proteome - IMPI (Integrated Mitochondrial Protein Index) 2017 - provided an opportunity for exploration of mitochondrial proteome history and the application of this knowledge to the understanding of gene function, disease and ageing. To facilitate the exploration of the mitochondrial proteome, I created a manually curated dataset of 190,097 predicted orthologues of the 1,550 IMPI 2017 human genes across 359 species, using reciprocal best hit analysis as the basis for orthologue prediction. I used this to explore gene history and the potential for phylogenetic profiling to predict the function of uncharacterised genes. This inspired the use of phylogenetic profiling within two phyla of animals, to link presence and absence of metabolic genes to the function of mitochondrial transporters. Potential transport substrates were predicted for two groups of uncharacterised mitochondrial carriers. I also used the dataset to identify features of genes associated with monogenetic disease, as well as differences between recessive and dominant disease genes. A similar orthologue identification method was used to explore the total sequenced viral proteome for potential orthologues of mitochondrial proteins. This showed that a range of mitochondrial proteins are shared with viruses, potentially facilitating the co-opting of mitochondrial function during viral infection of eukaryotic cells. I then used orthology to explore the conservation of residues linked to protein acetylation and identify a link with lifespan in warm-blooded vertebrates. In conclusion, I have used orthology to further the understanding of human mitochondrial proteome history and developed applications of this information. For example, phylogenetic features of disease genes are being used as part of a wider pipeline to predict mitochondrial disease genes. Furthermore, predicted substrates of the SLC25A14/30 mitochondrial carriers are being tested. My dataset provides further opportunities to explore the evolution and function of the mitochondrion.

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