<p>The ability to manipulate the coordination chemistry of metal ions has significant ramifications for the study and treatment of metal-related health concerns, including iron overload, UV skin damage, and microbial infection among many other conditions. To address this concern, chelating agents that change their metal binding characteristics in response to external stimuli have been synthesized and characterized by several spectroscopic and chromatographic analytical methods. The primary stimuli of interest for this work are light and hydrogen peroxide.</p><p>Herein we report the previously unrecognized photochemistry of aroylhydrazone metal chelator ((E)-N&#8242;-[1-(2-hydroxyphenyl)ethyliden]isonicotinoylhydrazide) (HAPI) and its relation to HAPI metal binding properties. Based on promising initial results, a series of HAPI analogues was prepared to probe the structure-function relationships of aroylhydrazone photochemistry. These efforts elucidate the tunable nature of several aroylhydrazone photoswitching properties.</p><p>Ongoing efforts in this laboratory seek to develop compounds called prochelators that exhibit a switch from low to high metal binding affinity upon activation by a stimulus of interest. In this context, we present new strategies to install multiple desired functions into a single structure. The prochelator 2-((E)-1-(2-isonicotinoylhydrazono)ethyl)phenyl (E)-3-(2,4-dihydroxyphenyl)acrylate (PC-HAPI) is masked with a photolabile trans-cinnamic acid protecting group that releases umbelliferone, a UV-absorbing, antioxidant coumarin along with a chelating agent upon UV irradiation. In addition to the antioxidant effects of the coumarin, the released chelator (HAPI) inhibits metal-catalyzed production of damaging reactive oxygen species. Finally a peroxide-sensitive prochelator quinolin-8-yl (Z)-3-(4-hydroxy-2-((4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl)oxy)phenyl)acrylate (BCQ) has been prepared using a novel synthetic route for functionalized cis-cinnamate esters. BCQ uses a novel masking strategy to trigger a 90-fold increase in fluorescence emission, along with the release of a desired chelator, in the presence of hydrogen peroxide.</p> / Dissertation

Orientador: Priscila Lupino Gratão / Resumo: As plantas estão expostas a adversidades no ambiente que as circundam, como a contaminação por cádmio (Cd). Este metal pesado tem aumentado na atmosfera devido a atividades humanas. As plantas podem absorver o Cd, causando sérias alterações estruturais, fisiológicas e bioquímicas. As plantas desenvolveram sistemas de defesa complexos, incluindo mecanismos não enzimáticos e enzimáticos para evitar uma cascata de oxidação descontrolada causada pelo estresse oxidativo. Alguns elementos, como o selênio (Se), se utilizados em concentração adequadas, podem induzir uma melhora no sistema antioxidante, no crescimento e nos atributos fotossintéticos. Ainda é pouco conhecido o papel do Se nas respostas das plantas ao estresse. O objetivo deste trabalho foi obter novas informações sobre o papel do selenato e selenito no sistema de desintoxicação das plantas, incluindo a avaliação da nutrição mineral, atividade de enzimas antioxidantes e conteúdo de compostos não enzimáticos, pigmentos, alterações estruturais e o papel do Se na modulação do etileno, com o uso de mutantes hormonais como ferramenta. Nossos dados indicam que o Se é uma estratégia interessante para melhorar o metabolismo da planta sob condições normais ou estressantes. O selênio pode induzir aumento da ação do metabolismo de defesa antioxidante, provavelmente devido a alterações na sinalização do etileno. Além disso, em condições normais, o Se induz alterações estruturais nas células, o que pode contribuir para o desenvolvim... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Cadmium (Cd) contamination is a worldwide concern and one of the most severe causes of abiotic stress in plants, triggering losses in crop production and contamination risks to human health. This heavy metal increased in atmosphere due to human activities. Plants can uptake Cd, causing serious changes in structural, physiological and biochemical processes. Plants developed a complex defence systems including non-enzymatic and enzymatic mechanism to avoid oxidative stress and prevent an uncontrolled oxidation cascade. Some elements, such as selenium (Se), if used in adequate concentration, may induce an improvement in antioxidant system, growth and photosynthetic attributes. It is still unknown the mechanisms of Se in stress responses. The aim of this work was get new insights about the role of selenate and selenite-mediated detoxification strategies, including the evaluation of mineral nutrition, the activity of antioxidant enzymes and non enzymatic compounds, pigments, structural alterations and the role of Se in modulate ethylene, with the use of hormonal mutants as a tool. Our data indicates that Se is an interesting strategy to improve plant metabolism under normal or Cd stressful-condition. Selenium may induce enhancement in antioxidant defence metabolism, probably due to alterations in ethylene signalling. Moreover, under normal condition Se induce structural alterations in cells, which may contribute to plant development. Thus, the information available in this work is... (Complete abstract click electronic access below) / Doutor

The detrimental effects of oxidative stress caused by the accumulation of Reactive Oxygen Species (ROS) have been acknowledged as major factors in aging, senescence and several neurodegenerative diseases and conditions such as Parkinson’s disease and stroke (ischemia/reperfusion). Mammalian models are extremely susceptible to these stresses that follow the restoration of oxygen after anoxia; however, some organisms including the freshwater turtle Trachemys scripta can withstand several bouts of anoxia and repeated reoxygenation without any apparent pathology. T. scripta thus provides us with an alternate vertebrate model in which we can investigate physiological mechanisms of neuroprotection without the damaging effects that come with oxidative stress. The major objective of this study was to investigate the protective mechanisms in the turtle brain under conditions of anoxia and oxidative stress. Specifically, the focus is on the Methionine Sulfoxide Reductase system (Msr), an antioxidant and cellular repair system, and how it is regulated to protect the brain against such stressors. Previous studies in my lab have demonstrated that Msr mRNA and protein levels are differentially upregulated during anoxia and reoxygenation. To investigate the regulation of Msr, FOXO3a was directly induced by transfecting a human FOXO3a plasmid into turtle brain cell cultures, as FOXO3a has been shown to regulate MsrA levels in other animal models. Pharmacological manipulation of FOXO3a was also performed using the green tea extract Epigallocatechin gallate (EGCG) as it has been shown to increase expression of FOXO3a during oxidative stress conditions in other models. I found that an induction of human FOXO3a increased FOXO3a levels and showed protection against cell death during oxidative stress. Furthermore, treatment of cells with EGCG increased expression of FOXO3a only when the cells were exposed to oxidative stress and decreased cell death. Induction of FOXO3a and EGCG treatment did not increase MsrA levels, however MsrB3 levels were upregulated under both treatments but only in the presence of oxidative stress. These results suggest that MsrA and MsrB3 protect the cells from oxidative stress damage through different molecular pathways and that EGCG may be a therapeutic target to treat diseases related to damage by oxidative stress. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

The oxidation of methionine (Met) into methionine sulfoxide (met-(o)) leads to deleterious modifications to a variety of cellular constituents. These deleterious alterations can be reversed by enzymes known as methionine sulfoxide reductases (Msr). The Msr (MsrA and MsrB) family of enzymes have been studied extensively for their biological roles in reducing oxidized Met residues back into functional Met. A wide range of studies have focused on Msr both in vivo and in vitro using a variety of model organisms. More specifically, studies have noted numerous processes affected by the overexpression, under expression, and silencing of MsrA and MsrB. Collectively, the results of these studies have shown that Msr is involved in lifespan and the management of oxidative stress. More recent evidence is emerging that supports existing biological functions of Msr and theorizes the involvement of Msr in numerous biological pathways. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Oxidative stress (OS) is strongly implicated in age-related neurodegeneration and other diseases. Under OS, the production of excessive oxidants leads to increased damages to cellular components. Recently, RNA has been discovered as a major target of oxidative damage, including the creation of abasic sites. In this work, we developed a method for quantifying abasic RNA in cell. Using this method, we have examined the potential role of the RNA-processing cellular foci, stress granule (SG) and processing bodies (PB) in eliminating abasic RNA in situ. We demonstrated that RNA is a major target of oxidative damage, constituting the majority of OS-induced abasic nucleic acids in HeLa cell. Importantly, the level of abasic RNA is strongly correlated with SG abundance. Furthermore, inhibition of SG/PB formation causes accumulation of abasic RNA, suggesting that SG/PB participates in removing oxidized RNA and protects cells under OS, which offers novel targets for therapeutic intervention in age-related diseases. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Ngai Lei-Ka. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 113-125). / Abstracts in English and Chinese. / List of Abbreviations --- p.ix / List of Tables --- p.x / List of Figures --- p.xii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Flavonoids --- p.1 / Chapter 1.1.1 --- The six major classes of flavonoids --- p.1 / Chapter 1.1.1.1 --- Flavonones --- p.1 / Chapter 1.1.1.2 --- Flavones --- p.2 / Chapter 1.1.1.3 --- Flavonols --- p.2 / Chapter 1.1.1.4 --- Isoflavonoids --- p.2 / Chapter 1.1.1.5 --- Anthocyanidins --- p.3 / Chapter 1.1.1.6 --- Flavans --- p.3 / Chapter 1.1.2 --- Structural variation of flavonoids --- p.3 / Chapter 1.1.3 --- The roles of flavonoids --- p.6 / Chapter 1.2 --- "Free radicals, oxidative stress and antioxidants" --- p.7 / Chapter 1.2.1 --- Oxidants and free radicals --- p.7 / Chapter 1.2.2 --- Lipid peroxidation (LPO) --- p.8 / Chapter 1.2.3 --- Oxidative stress and human diseases --- p.9 / Chapter 1.2.4 --- Role of food antioxidants --- p.10 / Chapter 1.2.5 --- Synthetic and natural food antioxidants --- p.11 / Chapter 1.3 --- Antioxidant activity of flavonoids --- p.12 / Chapter 1.4 --- Determination of antioxidant activity --- p.13 / Chapter 1.4.1 --- Trolox equivalent antioxidant capacity (TEAC) assay --- p.13 / Chapter 1.4.2 --- DPPH radical scavenging assay --- p.14 / Chapter 1.4.3 --- β-carotene bleaching assay --- p.15 / Chapter 1.5 --- Single cell gel electrophoresis assay (Comet assay) --- p.16 / Chapter 1.6 --- Determination of the genotoxicity --- p.18 / Chapter 1.7 --- Research objectives --- p.19 / Chapter 2 --- Materials and Methods --- p.26 / Chapter 2.1 --- Standards and reagents --- p.26 / Chapter 2.2 --- Sample Preparation --- p.26 / Chapter 2.3 --- Trolox equivalent antioxidant capacity (TEAC) assay --- p.27 / Chapter 2.4 --- DPPH´Ø radical scavenging assay --- p.28 / Chapter 2.5 --- β-carotene bleaching assay --- p.29 / Chapter 2.6 --- The comet assay --- p.30 / Chapter 2.6.1 --- Preparation of reagents --- p.31 / Chapter 2.6.2 --- Blood sample --- p.32 / Chapter 2.6.3 --- Optimal condition of comet assay --- p.32 / Chapter 2.6.3.1 --- Induction of DNA damage --- p.32 / Chapter 2.6.3.2 --- Antioxidant pre-treatment --- p.32 / Chapter 2.6.4 --- Hydrogen peroxide (H2O2) treatment --- p.32 / Chapter 2.6.4.1 --- Pre-incubation system --- p.32 / Chapter 2.6.4.2 --- Co-incubation system --- p.33 / Chapter 2.6.5 --- Slide preparation --- p.33 / Chapter 2.6.6 --- Cell lysis --- p.33 / Chapter 2.6.7 --- Alkaline treatment and electrophoresis --- p.34 / Chapter 2.6.8 --- Neutralization --- p.34 / Chapter 2.6.9 --- Quantification of DNA damage --- p.34 / Chapter 2.6.10 --- Cell viability analysis --- p.35 / Chapter 2.6.11 --- Statistical Analysis --- p.35 / Chapter 2.7 --- Mutatox® test --- p.36 / Chapter 2.8 --- Statistical analysis --- p.36 / Chapter 3 --- Result --- p.45 / Chapter 3.1 --- Determination of antioxidant activity using Trolox equivalent antioxidant capacity (TEAC) assay --- p.45 / Chapter 3.1.1 --- Trolox standard reference --- p.45 / Chapter 3.1.2 --- Antioxidant activity: ABTS´Ø+ scavenging capacity --- p.45 / Chapter 3.2 --- Evaluation of antioxidant activity using free radical scavenging assay --- p.46 / Chapter 3.2.1 --- Free radical scavenging abilities at 5 minutes --- p.46 / Chapter 3.2.2 --- Antiradical efficiency --- p.47 / Chapter 3.3 --- Evaluation of antioxidant activity using β-carotene bleaching assay --- p.47 / Chapter 3.3.1 --- Optimal incubation time --- p.47 / Chapter 3.2.2 --- Antioxidant activities on β-carotene bleaching assay --- p.47 / Chapter 3.4 --- Structure and antioxidant activities relationship (SAR) of flavonoids --- p.48 / Chapter 3.4.1 --- Effect of hydroxylation on the antioxidant activities of flavonoids --- p.48 / Chapter 3.4.1.1 --- Hydroxylation positions --- p.48 / Chapter 3.4.1.2 --- Polyhydroxylation --- p.48 / Chapter 3.4.2 --- Importance of B ring structure --- p.49 / Chapter 3.4.2.1 --- Increase hydroxylation in B ring --- p.49 / Chapter 3.4.2.2 --- The othro-dihydroxyl arranagement in B ring --- p.49 / Chapter 3.4.3 --- Importance of C ring structure --- p.50 / Chapter 3.4.3.1 --- The presence of a hydroxyl group at C3 --- p.50 / Chapter 3.4.3.2 --- The blockage of hydroxylation at C3 --- p.50 / Chapter 3.4.3.3 --- The presence of a double bond between C2 to C3 --- p.50 / Chapter 3.4.3.4 --- The presence of a carbonyl group at C4 --- p.50 / Chapter 3.4.3.5 --- The conjugation of a carbonyl at with a double bond between C2 to C3 --- p.51 / Chapter 3.4.4 --- Effect of glycosylation --- p.51 / Chapter 3.5 --- Evaluation of protective effects on DNA damage using comet assay --- p.51 / Chapter 3.5.1 --- Optimization of conditions fro the determination of H2O2-induced DNA damage --- p.52 / Chapter 3.5.1.1 --- H2O2 concentration & treatment temperature --- p.52 / Chapter 3.5.1.2 --- H2O2 treatment time --- p.52 / Chapter 3.5.1.3 --- Sample volume --- p.52 / Chapter 3.5.2 --- Protective effect of vitamin C on DNA damage --- p.53 / Chapter 3.5.3 --- Protective effect of selected flavonoids on DNA damage --- p.53 / Chapter 3.5.4 --- Structure and antioxidant activities relationship (SAR) of flavonoids in comet assay --- p.54 / Chapter 3.5.4.1 --- The importance of B ring structures --- p.54 / Chapter 3.5.4.2 --- The importance of C ring structures --- p.54 / Chapter 3.6 --- Evaluation of genotoxicity of flavonoids using Mutatox test --- p.55 / Chapter 4 --- Discussion --- p.96 / Chapter 4.1 --- Comparison of antioxidant activities between hydrophilic and lipophilic assays --- p.97 / Chapter 4.2 --- Structure and antioxidant activity relationship of flavonoids --- p.98 / Chapter 4.3 --- The comet assay --- p.103 / Chapter 4.4 --- Comparison of protective effect on DNA damage between pre-incubation and co-incubation systems --- p.105 / Chapter 4.5 --- Structure and protective effect of flavonoids in the comet assay --- p.106 / Chapter 4.6 --- Genotoxicity of flavonoids --- p.108 / Chapter 4.7 --- Significance and future works --- p.108 / Chapter 5 --- Conclusion --- p.111 / References --- p.113

Orientador: Roberto Calderon Gonçalves / Banca: Simone Biagio Chiacchio / Banca: Raimundo de Souza Lopes / Banca: Fernando José Benesi / Banca: Débora Cristina Damasceno / Resumo: Nas espécies domésticas as pneumonias cursam com intensa resposta inflamatória e acúmulo de células fagocíticas nos pulmões, levando a danos expressivos das estruturas do trato respiratório e à função pulmonar devido ao estresse oxidativo decorrente da liberação de grandes quantidades de Espécies Reativas do Oxigênio (ERO) durante a explosão respiratória. O objetivo deste estudo foi analisar o status oxidativo, a resposta inflamatória e a gasometria arterial, de ovinos sadios (n=20) e com diagnóstico clínico de pneumonia (n=20). Inicialmente os animais foram submetidos ao exame clínico e divididos em dois grupos: I) G1/controle, composto pelos animais clinicamente sadios e II) G2, composto pelos animais portadores de pneumonia. O status oxidativo foi avaliado por determinação indireta da atividade enzimática da Superóxido Dismutase (SOD) e Glutationa Peroxidase (GSH-Px) e das concentrações de Glutationa total (GSH-t) e Substâncias Reativas ao Ácido Tiobarbitúrico (TBARS) no sangue periférico por método colorimétrico. A resposta inflamatória foi avaliada pelo hemograma e proteína total e fibrinogênio plasmáticos e a função pulmonar pela determinação das variáveis hemogasométricas Pressão Arterial de Oxigênio (PaO2), Pressão Arterial de Gás Carbônico (PaCO2), Hidrogeniônico (pH), Saturação de Oxigênio (SO2), Bicarbonato (HCO3¯), Dióxido de Carbono Total (TCO2) e Excesso de Bases (EB), avaliados em sangue arterial. O leucograma revelou leucocitose com neutrofilia, eosinofilia, monocitose e linfopenia nos animais doentes (p<0,05). Com relação aos parâmetros bioquímicos, os ovinos portadores de pneumonia apresentaram aumento significativo (p>0,05) da concentração de fibrinogênio e proteína plasmática total. Os animais portadores de pneumonia apresentaram diminuição estatisticamente... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In domestic species, pneumonia is accompanied by intense inflammatory response and accumulation of phagocytic cells in the lungs, causing structural damage of the respiratory tract due to oxidative stress resulting from the release of large amounts of Reactive Oxygen Species (ROS) during the respiratory burst. The aim of this study was to analyze the oxidative status, inflammatory response and arterial blood gases values in healthy sheep (n=20) and animals with a clinically diagnosed pneumonia (n = 20). After physical examination the animals were divided into two groups: i) G1/control, composed of clinically healthy animals and ii) G2, composed of animals with pneumonia. The oxidative status was assessed by indirect determinations of enzymatic activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and concentrations of total glutathione (GSH-t) and thiobarbituric acid reactive substances (TBARS) in peripheral blood by a colorimetric method. The inflammatory response was evaluated by complete blood count and total protein and plasma fibrinogen. The lung function was evaluated by determinations of blood gas parameters in arterial blood: Oxygen Pressure (PaO2) Pressure of Carbon Dioxide (PaCO2), Pressure Hydrogen (pH), Oxygen Saturation (SO2), Bicarbonate (HCO3¯), Total Carbon Dioxide (TCO2) and Base Excess (EB). The leucogram results showed Leukocytosis with neutrophilia, eosinophilia, monocytosis and lymphopenia in sick animals (p<0,05). With regard to biochemical parameters, sheep with pneumonia showed a significant increase (p<0,05) of fibrinogen and total plasma protein concentrations. The animals from group G2 had a statistically significant reduction (p<0,05) in SOD and GSH-Px enzymatic activity and GSH-t concentration, while TBARS concentration was significantly higher (p<0,05). Arterial blood... (Complete abstract click electronic access below) / Doutor

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / In last years, considerable efforts have been made to identify neuroactive and neuroprotective peptides derived from the venom of different natural species. In this work, were studied the activity of Dinoponera quadriceps native (DqV) and denatured (DqDV) venom on chemically induced seizures models in vivo and on in vitro cortical astrocytes viability. Male Swiss mice (28- 33g) were pretreated with DqV (0.1 or 0.5 mg/kg, e.v., n = 6-8), DqDV (0.5 or 2.0 mg/kg, i.p., n = 6-8) or DqDV (0.1 or 0.5 mg/kg, e.v., n = 6-8). 30 minutes after the intraperitoneal pretreatment or ten minutes after intravenous pretreatment with the venom was induced seizures in all animals by the administration of pentylenetetrazole (80 mg/kg) pilocarpine (400 mg/kg) or strychnine (3.0 mg/kg). In behavioral analysis, we recorded the time to the first seizure and to death and the percentage of survival. To determine the parameters of oxidative stress was dissected three brain areas (prefrontal cortex, hippocampus and striatum) of animals used in behavioral analysis, in order to determine the degree of lipid peroxidation, by measuring the levels of malondialdehyde (MDA), and the content of nitrite. In in vitro assay, cell viability of cortical astrocytes was determined after treatment with different concentrations of DqV, PTZ and DqV + PTZ. The data were analyzed by ANOVA followed by a Student Newman-Keuls (for in vivo tests) or Bonferroni (for in vitro experiments) as post hoc tests. It was observed that the DqV had effect only on the PTZ model, both in behavioral analysis as for the determination of the oxidative parameters. Pretreatment with DqV significantly reduced the time until the occurrence of first seizure (0.1 mg/kg: 77.83 Â 5.27 compared to the 101.0 Â 3.31 seconds in the control group; 0.5 mg/kg: 74.43 Â 3.94 compared to the 101.0 Â 3.31 seconds in the control group), while DqDV caused an increase in the percentage of survival when pretreated by i.p. (0.5 mg/kg: 25% of survival compared with 0% in the control group, 2.0 mg/kg: 62.5% of survival compared with 0% in control group) and e.v (0.5 mg/kg: 28.57% of survival compared with 0% in control group). routes. In relation to the oxidative stress parameters, both pretreatments with DqV and with DqDV caused increases of MDA levels in all three brain areas analyzed. The nitrite content also increased after pretreatment with DqV in the three areas of the brain and after pretreatment with DqDV via e.v., only in the hippocampus. About cell viability assays, were observed that DqV was not able to change this parameter. The PTZ reduced the cell viability of astrocytes in a dose-dependent way, with an IC 50 (cytotoxicity index to 50% of the cell population under study) corresponding to 33.12 mM. The combined treatment of DqV (100 Âg/mL) and PTZ (IC 50) also caused a reduction in cell viability. The results suggest that the DqV, probably, has both neurotoxic and neuroprotective components, and that the astrocytes should be the cells involved in the venomâs neurotoxicity. / Nos Ãltimos anos, esforÃos considerÃveis tÃm sido feitos no sentido de identificar peptÃdeos naturais neuroativos e neuroprotetores derivados do veneno de diferentes espÃcies animais. Nesse trabalho foi estudada a atividade do veneno de Dinoponera quadriceps nativo (vDq) e desnaturado (vdDq) em modelos animais de convulsÃo quimicamente induzidos in vivo e sobre a viabilidade de astrÃcitos corticais in vitro. Camundongos Swiss machos (28-33g) foram prÃ-tratados com o vDq (0,1 ou 0,5 mg/kg, e.v, n= 6-8), vdDq (0,5 ou 2,0 mg/kg, i.p., n= 6-8) ou com vdDq (0,1 ou 0,5 mg/kg, e.v., n= 6-8). Meia hora apÃs o prÃ-tratamento intraperitoneal ou dez minutos apÃs o prÃ-tratamento endovenoso com o veneno foi induzida a convulsÃo em todos os animais atravÃs da administraÃÃo de pentilenotetrazol (80 mg/kg), pilocarpina (400 mg/kg,) ou estricnina (3,0 mg/kg). Na anÃlise comportamental, foram registrados os tempos para ocorrÃncia da primeira convulsÃo e morte e o percentual de sobrevida. Para determinaÃÃo dos parÃmetros de stress oxidativo foram utilizadas trÃs Ãreas cerebrais (cÃrtex prÃ-frontal, hipocampo e corpo estriado) de animais utilizados na anÃlise comportamental, a fim de se determinar o grau de peroxidaÃÃo lipÃdica, pela mensuraÃÃo dos nÃveis de malondialdeÃdo (MDA), e o conteÃdo de nitrito. No ensaio in vitro, foi determinada a viabilidade celular de astrÃcitos corticais apÃs o tratamento com diferentes concentraÃÃes de vDq, PTZ e vDq + PTZ. Os dados foram analisados por ANOVA e Student-Newman-Keuls como pÃs-teste, para os ensaios in vivo, e ANOVA seguido pelo pÃs-teste de Bonferroni, para as experimentaÃÃes in vitro. Foi observado que o vDq apresentou efeito apenas no modelo de PTZ, tanto na anÃlise comportamental quanto na determinaÃÃo dos parÃmetros oxidativos. O prÃ-tratamento com vDq reduziu significativamente o tempo para ocorrÃncia da primeira convulsÃo (0,1 mg/kg: 77,83 Â 5,27 comparado com 101,0 Â 3,31 segundos no grupo controle; 0,5 mg/kg: 74,43 Â 3,94 comparado com 101,0 Â 3,31 segundos no grupo controle), enquanto que o vdDq causou aumento do percentual de sobrevida quando prÃ-tratado por via i.p. (0,5 mg/kg: 25% de sobrevida comparado com 0% no grupo controle; 2,0 mg/kg: 62,5% de sobrevida comparado com 0% no grupo controle) e e.v (0,5 mg/kg: 28,57% de sobrevida comparado com 0% no grupo controle). Em relaÃÃo aos parÃmetros de estresse oxidativo, tanto o prÃ-tratamento com o vDq quanto com o vdDq causaram aumentos dos nÃveis de MDA nas trÃs Ãreas cerebrais analisadas. O conteÃdo de nitrito tambÃm sofreu elevaÃÃo apÃs prÃ-tratamento com vDq, nas trÃs Ãreas cerebrais, e apÃs o prÃ-tratamento com vdDq, via e.v., apenas no hipocampo. Quanto aos ensaios de viabilidade celular, foi observado que o vDq, isoladamente, nÃo foi capaz de alterar esse parÃmetro. O PTZ causou reduÃÃo da viabilidade de astrÃcitos de modo dose-dependente e com uma IC 50 (Ãndice de citotoxicidade para 50% da populaÃÃo celular em estudo) correspondente a 33,12 mM. O tratamento combinado entre vDq (100 Âg/mL) e PTZ (IC 50) tambÃm causou reduÃÃo da viabilidade das cÃlulas. Os resultados sugerem que o vDq possivelmente apresenta ambos componentes neurotÃxicos e neuroprotetores, e os astrÃcitos devem ser uma das cÃlulas envolvidas na neurotoxicidade do veneno.

Submitted by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2016-04-04T14:38:17Z No. of bitstreams: 1 Alessandra Melise Golke.pdf: 1584787 bytes, checksum: c4cea85302181139401e8596c156ca0a (MD5) / Made available in DSpace on 2016-04-04T14:38:18Z (GMT). No. of bitstreams: 1 Alessandra Melise Golke.pdf: 1584787 bytes, checksum: c4cea85302181139401e8596c156ca0a (MD5) Previous issue date: 2015-07-27 / A malária é causada por protozoários do gênero Plasmodium, sendo que o P. falciparum é responsável pela maioria das mortes. O quadro clínico dessa parasitose inclui febre, calafrios, cefaleia, vômito, diarreia, anemia, coma e morte. O mais antigo antimalárico é a quinina, um alcaloide obtido a partir da casca da árvore de espécies de Cinchona. Devido a sua toxicidade e ao surgimento de novos fármacos, seu uso foi limitado, porém voltou a ter maior importância em virtude da resistência do plasmódio a outros medicamentos. Uma alternativa para minimizar a toxicidade é o desenvolvimento de uma forma farmacêutica capaz de tornar esse fármaco menos tóxico, como os sistemas nanoencapsulados. O presente trabalho teve como objetivo verificar parâmetros hematológicos, bioquímicos e de estresse oxidativo em ratos Wistar tratados com nanocápsulas contendo quinina. Os animais foram divididos em quatro grupos, os quais receberam os seguintes tratamentos: controle (solução salina - NaCl 0,9%); quinina livre (75mg/Kg/dia); nanocápsulas brancas; nanocápsulas contendo quinina (75mg/Kg/dia). As formulações foram administradas três vezes ao dia por via intraperitoneal durante sete dias consecutivos. No oitavo dia os ratos foram eutanasiados e o sangue venoso foi coletado para análises posteriores. O tratamento com nanocápsulas contendo quinina foi capaz de manter os níveis hematológicos dentro dos limites normais. Os marcadores das funções cardíaca, hepática e renal apresentaram níveis sanguíneos significativamente diminuídos no grupo tratado com nanocápsulas contendo quinina em relação ao grupo tratado com quinina livre. As enzimas antioxidantes catalase, superóxido dismutase e glutationa peroxidase apresentaram uma atividade significativamente mais elevada no grupo tratado com nanocápsulas contendo quinina comparado ao grupo quinina livre, assim como o nível de glutationa reduzida. A quinina foi capaz de induzir dano lipídico, proteico e genético, e sua nanoencapsulação atenuou o dano. Assim, estes resultados demonstraram que a nanoencapsulação pode ser eficaz na redução dos efeitos adversos causados pela quinina, tornando este medicamento mais seguro para o tratamento da malária. / Malaria is caused by protozoa of the genus Plasmodium, which P. falciparum is responsible for the most deaths. The clinical picture this parasitosis include fever, chills, headache, vomit, diarrhea, anaemia, coma and death. The oldest antimalarial is quinine, an alkaloid obtained bark species Cinchona. Due to their toxicity and the appearance of new drugs, its use was limited, but again had greater importance because to Plasmodium resistance to other drugs. An alternative to minimize toxicity is the development of a pharmaceutical form capable of less toxic drug, as nanoencapsulated systems. This present work had objective to verify hematological, biochemical and oxidative stress parameters in rats Wistar treated with nanocapsules containing quinine. The animals were divided into four groups which received the following treatments: control (solution saline - 0.9% NaCl); free quinine (75mg/kg/day); blank nanocapsules; quinine-loaded nanocapsules (75 mg/kg/day). The formulations were administered three times a day intraperitoneally during seven consecutive days. On the eighth day the rats were euthanized and venous blood was collected for followed analysis. Treatment with quinine-loaded nanocapsules was able to maintain the blood levels with normal limits. The markers of cardiac, hepatic and renal function showed blood levels significantly decreased in the group treated with quinine-loaded nanocapsules compared to the group treated with free quinine. The antioxidant enzymes catalase, superoxide dismutase and glutathione peroxidase were significantly higher activity in the group treated with quinine-loaded nanocapsules compared to free quinine group, as well as the level of reduced glutathione. Quinine was able to induce lipid, protein and genetic damage, and its nanoencapsulation attenuate the damage. Then, these results demonstrate that nanoencapsulation can be effective in reducing the adverse effects caused by quinine, making this a safer medicament for treatment malaria.

"Oxidative stress is a type of cellular stress that can damage and kill cells. While it is naturally occurring, many non-natural substances found in our environment can also induce the formation of reactive oxygen species (ROS), which then cause oxidative stress within the cell. Oxidative stress has been shown to be involved in the death of neurons in a number of neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, and Amyotrophic Lateral Sclerosis. The primary causes for these diseases are still unknown; however, we do know oxidative stress plays a primary role in their development. In conditions where oxidative stress is present, adenosine receptor expression has been upregulated and has played a cytoprotective role, but the specific mechanism of action is unknown. In this thesis, oxidative stress was studied in a model eukaryote, Saccharomyces cerevisiae, and the effects of the expression of the human A1 and A2A receptors upon stress response was examined. Oxidative stress was induced by the addition of hydrogen peroxide at concentrations of .5 mM, 1 mM, and 2 mM. The growth of cells expressing either A1-GFP R or A2A-GFP R at the varying hydrogen peroxide concentrations were compared to the parental cells. Confocal microscopy was performed to determine the receptor expression levels, and to confirm the expression of the receptors via their GFP tag. Immunoblots were also performed to assess the receptor expression level at the differing hydrogen peroxide concentrations. A ROS assay was also performed to show the presence of ROS and oxidative stress in the cells. No significant increase in receptor level expression or localization for either A1 R or A2A R at the varying hydrogen peroxide concentrations was found. The data did show trends indicating that A2A receptors may help process the oxidative stress better than A1 receptors and that A2A receptor containing cells had a shorter doubling time. However, more research on this subject should be performed in the future. However, the concentration of hydrogen peroxide should be greatly increased for further experiments in S. cerevisiae in order to better differentiate the trends observed." / 1 / Bryan Goldman