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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.
31

Potencial antiinflamatório do extrato aquoso de Echinodorus macrophyllus e de suas frações em modelo de inflamação aguda / Anti-inflammatory potential of aqueous extract of Echinodorus macrophyllus and its fractions in acute inflammation model

Girlaine Pereira da Silva 14 February 2011 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / A Echinodorus macrophyllus (Alismataceae), conhecida como chapéu de couro no Brasil, é usada popularmente para tratar doenças reumáticas e inflamatórias. Neste trabalho, foram avaliados os efeitos antiinflamatórios do extrato aquoso de E. macrophyllus (EAEm) e suas frações etanólicas no modelo murino de air pouch. Para a obtenção das frações, 7 g do EAEm foram aplicadas em uma coluna cromatográfica aberta de sílica gel eluída com diferentes concentrações de etanol. Os cromatogramas do EAEm/frações foram obtidos usando um sistema de HPLC. Foram obtidas quatro frações, duas delas com maior rendimento. Resumidamente, a bolha de ar foi induzida pela injeção de 5 mL de ar estéril (s.c) no dorso de camundongos SW machos (25-35 g). Após 3 dias, mas 3 mL de ar estéril foram injetados para manter a bolha. No sexto dia, cada grupo (n = 4) foi tratado intraperitoneal (ip) ou oralmente (v.o) com EAEm (25 ou 250 mg/kg), Fr20 ou Fr40 (2,5, 25, 50 ou 100 mg/kg) e os controles com indometacina (10 mg/kg, v.o.) ou veículo (salina). Uma hora depois, 1 mL de salina ou de carragenina 1% estéril foi injetada dentro da bolha. Após 4 h, a cavidade foi lavada com NaCl 0,9%, EDTA 2 mM (1 mL), para a determinação do número de leucócitos, volume do exsudato e concentração de proteínas. Células do exsudato foram preparadas em citocentrífuga e coradas pelo método do Panótico para a contagem diferencial dos leucócitos. Cortes histológicos coletados dos diferentes grupos foram fixados com formol tamponado 10% (pH 7,4) por 7 dias, corados com HE e analisados em MO. A análise da expressão da iNOS e da COX-2 foi realizada em células do exsudato por RT-PCR. O acúmulo de nitrito (NO2−) no sobrenadante do cultivo de células RAW 264.7 foi determinado usando um ensaio colorimétrico baseado na reação de Griess. Os resultados foram expressos como média EP e comparados usando ANOVA seguido de teste de Dunnet. Os experimentos foram realizados em triplicata. No modelo air pouch, a injeção de carragenina 1% aumentou tanto a migração celular quanto a concentração de proteína no exsudato. Contudo, enquanto o pré-tratamento com a Fr40 aumentou a resposta inflamatória, o pré-tratamento com o EAEm e a Fr20, sobretudo por via i.p., inibiu esta resposta quando comparado ao grupo controle tratado apenas com o veículo. Assim, foram observadas as seguintes razões de inibição da migração de células: EAEm, i.p. a 25 mg/kg (66,44%) e a 250 mg/kg (87,27%) e Fr20 a 2,5 mg/kg (26,89%), 25 mg/kg (60,06%), 50 mg/kg (63,13%) e a 100 mg/kg (77,47%). Em relação à contagem diferencial, o EAEm e a Fr20 afetaram principalmente o número de neutrófilos, inibindo sua migração no exsudato. O EAEm e a Fr20 também reduziram a concentração total de proteínas no exsudato principalmente no tratamento i.p.; EAEm a 25 e 250 mg/kg mostrou 3,33 0,55 e 2,05 0,51 mg/mL, respectivamente, quando comparado aos grupos controles (Indometacina 2.88 0.64 mg/mL; Veículo 5.48 0.88 mg/mL). A Fr20 a 2,5, 25, 50 e 100 mg/kg mostrou 4,788 0,444, 1,417 0,519, 2,474 0,529 e 2,215 0, 361 mg/mL. A análise histológica mostrou infiltrado celular, principalmente composto de leucócitos polimorfonucleares ao longo da derme inflamada de animais tratados com veículo. O tratamento com o EAEm ou Fr20 reduziu a infiltração de leucócitos no tecido inflamado. Além disso, o tratamento com o EAEm e a Fr20 mostrou atividade supressora sobre a expressão de iNOS e COX-2, e mostrou efeitos inibitórios na produção de NO induzida por LPS. Concluindo, todos estes resultados confirmam o potencial antiinflamatório sugerido para esta planta e fornecem uma base para a compreensão de seus mecanismos moleculares de ação. Contudo, outros estudos devem ser realizados para melhor elucidar as vias pelas quais o EAEm e a Fr20 exercem seus efeitos antiinflamatórios. Além disso, estudos fitoquímicos devem ser realizados para identificar os compostos ativos no EAEm e na Fr20. / Echinodorus macrophyllus (Alismataceae), known as "chapéu de couro" in Brazil, is used popularly to treat rheumatic and inflammatory diseases. In this work we have evaluated the anti-inflammatory effects of the aqueous extract of E. macrophyllus (AEEm) and of its ethanolic fractions in mice air pouch model. Fractions were obtained by applying 7 g AEEm on a silica gel chromatography open column eluted with different ethanol concentrations. The fractions so obtained were evaporated under vacuum and lyophilized. Representatives chromatograms of EAEm/fractions were obtained using a HPLC system. We obtained four fractions, two with higher-yielding. Briefly, the air pouch was induced by 5 mL of sterile air injection (s.c.) on the back of male SW mice (25-35 g). After 3 days, 3 mL of sterile air has been injected again to keep it. After six days each group (n = 4) received intraperitoneal (i.p.) or oral (p.o.) treatment with AEEm (25 or 250 mg/kg), Fr20 or Fr40 (2.5, 25, 50 or 100 mg/kg) or controls indomethacin (10 mg/kg, p.o.) and vehicle (saline). One hour later 1 mL saline or carrageenan 1% sterile was injected into the pouch. After 4 h, the cavity was washed with NaCl 0.9%, EDTA 2 mM (1 mL), for determination of leukocyte numbers, final exudate volume and protein concentration. Cytospin preparations of exudates were stained with Panotic method for differential leukocyte count. Histological sections of tissue collected from different groups were fixed with 10% buffered formalin (pH 7.4) for 7 days and stained with HE and analyzed by MO. The iNOS and COX-2 expression analyses were performed on the exudate cells by RT-PCR. Accumulated nitrite (NO2−) in the media obtained from the RAW 264.6 cell cultures was determined using a colorimetric assay based on the Griess reaction. Results were expressed as mean SEM and compared using ANOVA and Dunnet‟s test. Experiments were performed in triplicate. In air pouch model, carrageenan 1% increased both the cell migration and the exudate protein level. However, while pretreatment with Fr40 increased inflammatory response, the pretreatment with AEEm and Fr20, mainly i.p. inhibited its when compared to the control group treated only the vehicle. So, the following rates of inhibition of cell migration were observed: AEEm, i.p. at 25 mg/kg (66.44%) and at 250 mg/kg (87.27%) and Fr20 at 2.5 mg/kg (26.89%), at 25 mg/kg (60.06%), at 50 mg/kg (63.13%) and at 100 mg/kg (77.47%). Regarding the differential count, the EAEm and Fr20 affected mainly the content of neutrophils, inhibiting the neutrophils migration in exudate. AEEm and Fr20 also reduced the total protein level in exudates mainly in the i.p. treatment. AEEm at 25 and 250 mg/kg showed 3.33 0.55 and 2.05 0.51 mg/mL, respectively, when compared to controls groups (Indomethacin 2.88 0.64 mg/mL; vehicle 5.48 0.88 mg/mL). Fr20 at 2.5, 25, 50 and 100 mg/kg showed 4.788 0.444, 1.417 0.519, 2.474 0.529 and 2.215 0.361 mg/mL. The histological analysis showed cellular infiltrate, mainly composed by polymorphonuclear leukocytes throughout the inflamed dermis of animals treated with vehicle. Treatment with AEEm or Fr20 reduced the leukocyte infiltrate on inflamed tissue. In addition, treatment with AEEm and Fr20 showed suppressive activity on iNOS and COX-2 expression, and showed inhibitory effects on LPS-induced nitric oxide production. In conclusion, all these findings support an anti-inflammatory potential suggested for this plant and provides a basis for understanding their action molecular mechanism. However, further studies should be undertaken to better elucidate the pathways by which AEEm and Fr20 exert their anti-inflammatory effects. In addition, phytochemical studies must be underway to identify active compounds in AEEm and Fr20.
32

Caracterização das ações do extrato da inflorescência da Achyrocline satureoides sobre a função de neutrófilos na inflamação / Characterization of Achyrocline satureoides inflorescence extract actions on the neutrophils role in inflammation

Éric Diego Barioni 01 July 2013 (has links)
Achyrocline satureoides (Lam) D.C., popularmente conhecida como \"marcela\", é utilizada popularmente para tratar diversas doenças, como mal estar gástrico e intestinal, inflamações, diabetes e outros. Como os mecanismos de ação do extrato de A. satureoides ainda não são conhecidos, o presente trabalho visou esclarecer os mecanismos antiinflamatórios do extrato bruto hidroalcoólico das inflorescências de A. satureoides, focando na migração e função fagocítica e microbicida de neutrófilos. Para tanto, o extrato hidroalcoólico foi administrado por gavage (50, 100 e 250mg/kg) em ratos Wistar, machos, adultos, e a inflamação foi induzida pela injeção do lipopolisacarídeo de E. coli (LPS; 2mL de solução; 500 µg/mL em PBS) no tecido subcutâneo dorsal (modelo da bolsa de ar). Animais controles receberam volumes equivalentes de veículo do extrato e indometacina (30mg/kg). Foram quantificados o número de neutrófilos (câmara de Neubauer e esfregaços corados por Panótico) e a concentração de Leucotrieno B4 e CINC-1 (ELISA) no foco de lesão; a interação leucócito-endotélio em vênulas da microcirculação mesentérica após estímulo in situ pelo lipopolisacarídeo de E.coli (LPS; 30µg/40µL; por microscopia intravital); a expressão de moléculas de adesão e do toll-like receptor (TLR-4), além da quantificação do burst oxidativo (induzido pelo miristato-acetato de forbol - PMA) e fagocitose em neutrófilos circulantes (citometria de fluxo); análise histológica e quantificação dos marcadores hepáticos (AST, ALT e Gama-GT) e renais (uréia e creatinina) no plasma por espectrofotometria. Os resultados obtidos mostraram que o tratamento com o extrato reduziu o número de neutrófilos e a concentração de LTB4 e CINC-1 na bolsa de ar; reduziu a expressão de TLR4 pelos neutrófilos circulantes e a porcentagem de neutrófilos positivos para L-selectina e β2-integrina; inibiu a adesão e o comportamento rolling de leucócitos ao endotélio microvascular; reduziu o burst induzido por PMA; aumentou o potencial de fagocitose, sem alterar o burst induzido por Staphylococcus aureus, não alterou a morfologia tecidual e a concentração sérica dos marcadores de atividade hepática e renal. Em conjunto, os dados obtidos mostram que dose, aparentemente, não tóxica do extrato de A. satureoides exerce efeito antiinflamatório in vivo frente ao LPS, quantificados pela redução da migração e pelas interferências nas atividades fagocítica e microbicida dos neutrófilos. / Achyrocline satureoides (Lam) D.C., popularly known as \"marcela\", is popularly used to treat several diseases, such as gastric and intestinal disorders, inflammation, diabetes and others. As the mechanisms of the extract of A. satureoides have not been elucidated, this study aimed to investigate the anti-inflammatory mechanisms of the crude hydroalcoholic extract of the flowers of A. satureoides, focusing on migration and phagocytic and microbicidal neutrophils function. The hydroalcoholic extract was administered by gavage (50, 100 and 250mg/kg) into male Wistar rats, adult, and inflammation was induced by injection of lipopolysaccharide E. coli (LPS; 2 mL of solution; 500µg/mL in PBS) into the dorsal subcutaneous tissue (air pouch model). Control animals received equivalent volume of extract vehicle or indomethacin solution (30mg/kg). It was quantified the numbers of neutrophils (Neubauer chamber and stained smears by Panoptic) and concentrations of leukotriene B4 (LTB4) and CINC-1 (ELISA) in the focus of the injury; the leukocyte-endothelium interactions in mesenteric venules of the microcirculation after stimulation by LPS (30µg/40µL; intravital microscopy); the adhesion molecules and toll-like receptor (TLR-4) expressions and quantification of oxidative burst and phagocytosis in circulating neutrophils (flow cytometry); histological analysis and the hepatic markers (AST, ALT and gamma-GT) and kidney (urea and creatinine) concentrations in plasma by spectrophotometry. Data obtained showed that the treatment reduced the numbers of neutrophils and concentrations of LTB4 and CINC-1 in the subcutaneous tissue; reduced the TLR4 expression by circulating neutrophils and the number of β2-integrin- and L-selectin-positive neutrophils; inhibited the leukocyte adhesion and the rolling behavior to vascular endothelium; reduced the burst evoked by PMA; increased the phagocytosis without changing the burst induced by Staphylococcus aureus; and did not alter the tissue morphology and concentration of hepatic and renal enzymes in the serum. Together, these data suggest that dose, apparently non-toxic, of extract of A. satureoides exerts anti-inflammatory effect in vivo, quantified by the reduced migration and by interference in the phagocytic and microbicidal activities of neutrophils.
33

Amino acid residues constituting the agonist binding site of the human P2X3 receptor and subunit stoichiometry of heteromeric P2X2/3 and P2X2/6 receptors

Wang, Haihong 28 March 2013 (has links)
Homotrimeric P2X3 and heteromeric P2X2/3 receptors are present in sensory ganglia and participate in pain perception. In order to develop pharmacological antagonists for these receptors, it is important to clarify which amino acid (AA) residues constitute the agonist binding pouch as well as to learn the stoichiometry of the receptor subunits forming a heteromeric receptor. We expressed the homomeric human (h)P2X3 receptor or its mutants in HEK293 cells and measured the ATP-induced responses by the whole-cell patch-clamp method. For the binding-site mutants, all conserved and some non-conserved AAs in the four nucleotide binding segments (NBSs) of the P2X3 subunit were sequentially replaced by alanine. Especially the positively charged AAs Lys and Arg appeared to be of critical importance for the agonist effects. We concluded that groups of AAs organized in NBSs rather than individual amino acids appear to be responsible for agonist binding at the P2X3 receptor. These NBSs are located at the interface of the three subunits forming a functional receptor. We were also interested to find out, whether two heteromeric receptors (P2X2/3 and P2X2/6), where P2X2 combines with two different partners, have an obligatory subunit stoichiometry of 1:2 or whether the subunit stoichiometry may be variable. For this purpose we used non-functional P2X2, P2X3 and P2X6 subunit-mutants to investigate the composition of heteromeric P2X2/3 and P2X2/6 receptors. The subunit stoichiometry of P2X2/3 and P2X2/6 was found to be 1:2 and 2:1, respectively. Thus, recognitions sites between P2X2 and its partners rather than random association may govern the subunit compositions of the receptor trimers.:Index of contents Introductory remarks „Wissenschaftlicher Anteil des Promovenden an der Publikation“ „Bibliographische Beschreibung“ I. Introduction Pain as a sensory quality Neuronal circuitry for pain processing and sensation in the PNS and CNS Transformation of thermal, mechanical and chemical stimuli into electrical activity by nociceptors; nociceptor-targeted therapeutic approaches Release mechanisms for nucleotides and their fate in the extracellular space Nucleotide receptor-types ATP-sensitive P2 receptors and pain-sensation References II. Scientific background and aims of my thesis ATP binding-sites of P2X3 receptors; subunit composition of P2X2/3 and P2X2/6 heteromeric receptors The aims of the present work III. Publications IV. Summary and conclusions Amino acid residues constituting the agonist binding site of the human P2X3 receptor ATP binding site mutagenesis reveals different subunit stoichiometry of functional P2X2/3 and P2X2/6 receptors „Eigenständigkeitserklärung“ Curriculum vitae Acknowledgements
34

TERMISKT SMARTA HANTERINGSSYSTEM FÖR LITIUMJONBATTERIER : Analys av litium-jonbatteriets termiska beteende

Kohont, Alexander, Isik, Roger Can January 2021 (has links)
Batteries play an important role in a sustainable future. As the development for better andsmarter batteries continues, new areas of use emerge boosting its demand. Controlling thetemperature of a battery cell is a vital objective to ensure its longevity and performance. Bothcooling and heating methods can be applied to keep the temperature within a certain rangedepending on its need. This study will review the technical aspects of lithium-ion batteries,observe the different thermal management systems and cooling methods, and lastly examinethe required cooling flow needed for a battery cell to prevent its temperature from rising tocritical levels during its discharge. Using CFD ANSYS Fluent as a simulation tool, the resultsshow that different charging rates, in terms of C-rate, require different rates of mass flow tocontrol the temperature. Simulating the cell with natural convection, the cell peaks at hightemperatures even at lower C-rates, reaching up to 36,4°C and 48,8°C for 1C and 2C,respectively. Applying the cooling method with a flow rate of 0,0077kg/s reduces thetemperature significantly, resulting in temperatures of 26,95°C and 31,27°C for 1C and 2C,respectively.
35

Topical Black Raspberries and Strawberries Bioincorporated with Selenium Reduce Experimental Oral Cancer

Warner, Blake Matthew 26 August 2013 (has links)
No description available.

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