• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 176
  • 108
  • 28
  • 27
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 411
  • 407
  • 231
  • 212
  • 178
  • 52
  • 39
  • 39
  • 38
  • 34
  • 33
  • 32
  • 29
  • 28
  • 28
  • 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.
111

An Investigation of Episodic Memory Performance in Relation to Inflammation in Children with Sickle Cell Disease

Iampietro, Mary Catherine January 2014 (has links)
It is now well established that children with sickle cell disease (SCD) demonstrate cognitive deficits even in the absence of clinical stroke, but studies in children who have not experienced a stroke or other neurological event are lacking. Systemic processes that occur in SCD, like chronic inflammation and hypoxia, have been associated with hippocampal damage and episodic memory deficits in a range of clinical populations and animal models. However, studies examining episodic memory performance in children with SCD and in relation to systemic processes are largely absent. The present study addressed these gaps in young children with SCD (Mage = 7.37 years, SD = 1.51) who had not experienced a clinical stroke. Participants (N = 31) completed various memory measures as part of a larger neuropsychological protocol and participated in routine clinical blood draws. Latent class analysis (LCA) was used to empirically define SCD groups based on measures of specific visual memory processes, and results revealed two distinct visual memory groups, characterized by (1) visual memory deficits, specifically in delayed recognition abilities, and (2) intact visual memory. Follow-up analyses revealed that the two classes did not significantly differ on verbal memory performance. The relation between memory processes and both biomarkers of inflammation and adaptive functioning also were examined with variable-centered analyses. Results showed only one significant relation between C-reactive protein (CRP) and a measure of verbal delayed recognition. In sum, young children with SCD demonstrate variable episodic memory performance, with most notable deficits in visual delayed recognition. Higher levels of CRP, a biomarker of inflammation, were associated with poorer verbal delayed recognition. The results indicate that young children with SCD experience deficits in memory, even in the absence of a neurological event, and specific memory processes should be assessed in these children to guide targeted interventions. / Psychology
112

Histamine as a Potential Initiator of Sickle Pain crisis by Mediation of Sickle Erythrocyte Adherence in a Shear-Dependent Manner

Wagner, Matthew Christian 11 April 2006 (has links)
The genetic disorder sickle cell anemia causes hemolytic anemia and sickle pain crisis, episodes of microvascular occlusion resulting in painful ischemic tissue damage. Pain crisis is thought to occur when sickle erythrocytes adhere in the post-capillary venule, partially occluding the vessel. The resulting slowed blood flow causes more extensive cell adherence and entrapment of rigid, deoxygenated erythrocytes until the vessel is entirely occluded. It was hypothesized that the inflammatory mediators histamine and tumor necrosis factor-, factors known to cause endothelial expression of adhesive ligands, might significantly increase sickle erythrocyte adhesion, and thus be capable of initiating sickle pain crisis. It was also hypothesized that the perfusion shear stress environment of the endothelium, known to be oscillatory and reduced in sickle cell patients, was a significant mediating factor of sickle cell adhesion. An in-vitro flow chamber using cultured endothelial cells and erythrocytes from blood samples of sickle cell anemic patients was used to quantify sickle erythrocyte adherence to stimulated and unstimulated endothelial cells under shear stresses from 1.0 to 0.1 dyne/cm2. Results showed that both endothelial stimulation and reduction of the perfusion shear stress increased sickle erythrocyte adherence. In combination, the use of inflammatory stimulation with reduced shear stress resulted in further increased adhesion, but only when above the range of 0.1 V 0.2 or 0.4 dyne/cm2, depending on the inflammatory mediator. Adhesion below this level of shear is not significantly increased by endothelial stimulation. The mechanism by which histamine mediates adhesion was investigated, and found to involve the endothelial H2 and H4 receptors and expression of the P-selectin ligand. These data suggest that irregular flow, typical of sickle microvasculature, may act in conjunction with the pro-inflammatory state of sickle vasculature and the histaminergic nature of some pain treatments to initiate or propagate sickle vaso-occlusion. Findings concerning histamine, tumor necrosis factor-alpha, and shear stress effects on adherence are discussed in relation to their possible applicability to patient health, future studies are outlined to confirm the relation of in vitro data to in vivo patient condition, and proposals are made for applying these methodologies to other potential mediators of sickle erythrocyte adhesion.
113

Regulation of Cytokine-Induced Adhesion Molecule Expression and Sickle Erythrocyte Adhesion to Microvascular Endothelial Cells by Intracellular Adenosine 3',5'-Cyclic Monophosphate and Nitric Oxide

Amos, Amanda Owings 05 April 2006 (has links)
Adhesion of sickle erythrocytes to vascular endothelium may initiate or propagate occlusive events in sickle cell anemia, many of which are accompanied by infection and the associated inflammatory response. Inflammatory markers are also present in sickle patients during asymptomatic periods. Inflammatory cytokines upregulate expression of endothelial adhesion molecules that promote adhesion of sickle erythrocytes. The data in this work demonstrate that after 2 hrs of stimulation with the cytokine TNF- and alpha;, E-selectin, but not VCAM-1 is upregulated on human dermal microvascular endothelial cells. After 6 hrs of TNF- and alpha; stimulation, both VCAM-1 and E-selectin expression are upregulated on MECs, and sickle erythrocytes bind to both receptors. Because strategies to control inflammation-associated adhesion in vivo may need to account for both VCAM-1 and E-selectin mediated events, control of intracellular signaling pathways leading to receptor expression is an attractive strategy for inhibiting adhesion. Cyclic AMP and nitric oxide are two intracellular signaling molecules important to cytokine-induced receptor expression. The data in this work demonstrate that TNF- and alpha; induced VCAM-1 and E-selectin expression on endothelial cells and sickle erythrocyte adhesion are abated by increasing endothelial cyclic AMP concentrations using Forskolin, IBMX, or Bt2cAMP. Conversely, when sickle erythrocytes, rather than endothelial cells, are treated with reagents that increase intracellular cAMP, adhesion to unstimulated endothelial cells is increased in some patients. Treatment of endothelial cells with reagents such as SNP and DETA-NO that increase nitric oxide significantly inhibits VCAM-1, but not E-selectin expression, induced by TNF- and alpha; stimulation and significantly inhibits sickle erythrocyte adhesion. Treatment of sickle erythrocytes directly with these reagents may also inhibit adhesion. Together these data suggest that cAMP- and nitric oxide-dependent signaling are useful therapeutic targets to inhibit cytokine-induced sickle erythrocyte adhesion to endothelium.
114

Perfil oxidativo e bioquímico em pacientes que apresentam anemia falciforme ou traço falciforme / Oxidative and biochemistry profile in sickle cell trait subjects and sickle cell anaemia patients

Manfredini, Vanusa January 2008 (has links)
A Anemia Falciforme (AF) é uma doença autossômica recessiva e, dentre as hemoglobinopatias, é a mais comum das alterações hematológicas hereditárias conhecidas no homem. Sua distribuição é ampla, abrangendo todos os continentes. AF foi a primeira doença caracterizada em nível molecular. É causada por uma mutação no gene beta da globina, produzindo uma alteração estrutural na molécula. No gene da globina beta S, há a substituição de uma base nitrogenada do códon GAG para GTG, resultando na substituição do ácido glutâmico (Glu) pela valina (Val) na posição número seis da globina beta. Essa troca dos aminoácidos que resulta na HbS, altera estruturalmente a molécula e, sob determinadas condições, ocorre a polimerização, trazendo graves conseqüências ao indivíduo sintomático. As espécies reativas de oxigênio (ERO) podem causar profundas lesões em eritrócitos, diminuindo seu período de vida útil, em especial nos pacientes com AF. Acredita-se que, os eritrócitos falcizados estejam sob constante estresse oxidativo e, assim, liberem produtos de degradação da HbS, contribuindo para a progressão da doença. Dessa forma, o dano oxidativo agrava a fisiopatologia dos doentes falciformes. Utilizando técnica espectrofotométrica, foram determinadas as atividades das enzimas antioxidantes catalase (CAT), glutationa peroxidase (GPx) e superóxido dismutase (SOD) e quantificada a glutationa total (GSH) nos eritrócitos dos pacientes. Também determinou-se o dano oxidativo nas proteínas plasmáticas e no hemolisado celular pelo método do carbonil a 360 nm. Os níveis da peroxidação lipídica (MDA) e da vitamina C foram determinados por cromatografia líquida de alta performance (HPLC). Quantificou-se, por fim, os níveis de proteína C reativa ultra-sensível (CRPus) por técnica turbidimétrica. Os participantes da pesquisa (30 HbAA, 28 HbAS e 20 HbSS) foram selecionados junto ao Centro de Apoio do Portador de Anemia Falciforme (CAPAF/RS) e/ou cadastrados no Laboratório de Hematologia da Faculdade de Farmácia (UFRGS). Os doentes falciformes foram identificados por HPLC e confirmados por estudo molecular, utilizando a reação da polimerase em cadeia (PCR). Todos os indivíduos assinaram o termo de consentimento livre e esclarecido e foram submetidos a um questionário nutricional. Os dados obtidos foram expressos como médias ± desvio padrão e analisados utilizando-se o Teste ANOVA de uma via com posterior teste ad hoc. Os resultados do trabalho mostram que os indivíduos traço falciforme (HbAS) apresentam atividade significativamente elevada da CAT em relação aos indivíduos controle. Por outro lado, os doentes falciformes possuem maior atividade da GPx e SOD. O nível de GSH foi proporcionalmente maior nos HbSS seguido dos HbAS e HbAA. Observamos também, dano oxidativo em proteínas plasmáticas, mas não no hemolisado celular. Os HbSS possuem dano oxidativo em proteínas plasmáticas significativamente maior que nos demais grupos. Um aumento significativo da produção de MDA no soro dos HbSS foi observado, como um indicativo do aumento da auto-oxidação dos lipídios sob condições de estresse oxidativo. Os níveis séricos da vitamina C foram significativamente maiores nos HbSS que nos indivíduos controle. A CRPus apresentou-se significativamente elevada nos HbSS em relação aos HbAA. Esses resultados reforçam a idéia de que os pacientes com AF estão sujeitos a um estresse oxidativo crônico, o que contribui para a progressão das complicações dessa anemia hemolítica. Já, os indivíduos traço possuem elevada atividade das defesas antioxidantes capazes de reduzir o dano oxidativo em biomoléculas como proteínas e lipídios. / Sickle cell anaemia (SCA) is an autossomal recessive disease and, among the hemoglobinopaties, is the most common of the known hereditary hematologic alterations in man. Its distribution is ample, enclosing all the continents. Sickle cell anaemia (SCA) was the first disease to be characterized on the molecular level. It is basically a red blood cell (RBC) disorder in which the gene encoding the human β-globin subunit presents a mutation with the resulting replacement of β6 glutamic acid (Glu) by valine (Val). This exchange of the amino acids that results in the HbS modifies the molecule structurally, and under determined conditions, the polymeration occurs, bringing serious consequences to the symptomatic individual. The reactive oxygen species (ROS) can cause deep injuries in erythrocytes, diminishing its period of useful life, specially in patients with sickle cell anaemia. Sickled erythrocytes are under constant oxidative stress and thus liberate products of degradation of the HbS, contributing for the progression of the disease. Because of the oxidative damage aggravates the pathophysiology of sickle cell patients. Using spectrophotometrically technique, catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), were determined the activities of antioxidant enzymes and total glutathione (GSH) quantified in the erythrocytes of the patients. We also determined oxidative damage of plasma proteins and in hemolysate using carbonyl assay at 360 nm. The levels of lipid peroxidation (MDA) and vitamin C were determined by high-performance liquid chromatography (HPLC). Finally, we quantified the levels of high sensitivity Creactive protein (hsCRP) using turbidimetry technique. The participants of the research (30 HbAA, 28 HbAS and 20 HbSS) were selected from Centro de Apoio ao Portador de Anemia Falciforme (CAPAF/RS) and/or registered in cadastre in Laboratório de Hematologia da Faculdade de Farmácia (UFRGS). Sickle cell patients had been identified by HPLC and confirmed by molecular study, using the polymerase chain reaction amplification (PCR). All individuals signed the term of free and clarified assent and were submitted to a nutricional questionnaire. Data were expressed as average ±SD and analyzed using ANOVA test of one way via with the post ad hoc test. Results show that sickle cell trait subjects (HbAS) had significantly high activity of CAT when compared to healthy controls. On the other hand, sickle cell patients had greater activity of GPx and SOD. The GSH levels was proportionally higher in the followed HbSS of the HbAS and HbAA. We also observe oxidative damage in plasma proteins, but not in the cellular hemolysate. HbSS have significantly higher oxidative damage in plasma proteins than other groups. A significant increasing of the production of MDA in the serum of the HbSS was observed as an indicative of the increasing of the auto-oxidation of the lipids under oxidative estress. Serum vitamin C levels in HbSS were significantly higher than healthy control. The hsCRP was presented significantly higher in HbSS than HbAA. These results reinforce the idea that patients with SCA are subjected to chronic oxidative stress, that contributes for the progression of this hemolytic anaemia. On the other hand, sickle cell trait subjects have higher antioxidant defenses that are able to reduce oxidative damage in biological macromolecules such as proteins and lipids.
115

Capacidade antioxidante na Hb S: influência de talassemia alfa, haplótipos do gene βS globina e melatonina

Shimauti, Eliana Litsuko Tomimatsu [UNESP] 01 July 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:32:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-07-01Bitstream added on 2014-06-13T18:43:20Z : No. of bitstreams: 1 shimauti_elt_dr_sjrp.pdf: 703318 bytes, checksum: bf063f504644666407e22683da45d271 (MD5) / A anemia falciforme (Hb SS), caracterizada por estados de inflamação crônica e eventos de agressão isquêmica e reperfusão pode causar danos oxidativos às macromoléculas biológicas. Os genes epistáticos e os haplótipos do gene da globina βS são possíveis moduladores de variabilidade fenotípica na Hb SS. A melatonina pode atenuar o estresse oxidativo e abrandar a morbidade. O objetivo deste foi analisar a influência de talassemia alfa (-α3.7), haplótipos do gene βS e melatonina na capacidade antioxidante total e expressão fenotípica, em indivíduos com Hb SS e Hb AS. Para avaliar o nível de melatonina sérica foram selecionadas 15 amostras de pacientes com Hb SS e 24 com Hb AA da região noroeste do estado do Paraná (NOPR). A triagem das hemoglobinas foram realizadas por métodos eletroforéticos e cromatográfico, e a caracterização genotípica da Hb S por meio de PCR- RFLP e PCR-AE. As espécies reativas de ácido tiobarbitúrico (TBARS), e a capacidade antioxidante total em equivalência ao Trolox (TEAC) foram determinadas por meio da espectrofotometria. A melatonina foi estimada por meio de HPLC. O estado redox foi analisado selecionando amostras de 68 indivíduos com Hb SS, 53 com Hb AS e 149 com Hb AA, das regiões sul e sudeste do Brasil. Para analisar a influência dos genes epistáticos sobre a TEAC, melatonina e expressão fenotípica, foram selecionadas 17 amostras com Hb SS, 30 com Hb AS, e 30 com Hb AA, da NOPR. O critério para elegebilidade foi ser não fumantes não gestantes, não etilistas e estar na fase estável para os indivíduos com HbSS. Os haplótipos do gene βS e a talassemia -α3.7 foram identificados por meio de PCR-RFLP e PCR multiplex, respectivamente. Os níveis séricos de melatonina apresentaram-se reduzidos nos indivíduos com Hb SS (P<0,001), e os TBARS e TEAC elevados quando comparados a grupo controle (P<0,001 e P<0,01 respectivamente)... / Sickle cell disease (Hb SS), characterized by chronic inflammation and ischemic damage episodes and reperfusion, comprises excessive production of free radicals which can cause oxidative damage to biologic macromolecules. The epistatic genes and the polymorphism of the βS globin gene region are possible modulators of phenotypical variability of sickle cell disease in Hb SS. Melatonin can diminish both the oxidative stress and morbidity. The objective of this study was to analyze the influence of -α-3.7 thalassemia and from βS gene haplotypes on total anti-oxidant capacity, melatonin serum levels and phenotypical expression in individuals with Hb SS and Hb AS. To evaluate melatonin serum level 15 samples with HbSS and 24 with Hb AA from the northwest region of Paraná state (NOPR). The hemoglobin screenings were performed by electrophoretic and chromatographic methods and genotypic characterization of Hb S by PCR- RFLP and PCR-AE. The concentrations of thiobarbituric acid reactive substances (TBARS), used as markers of oxidative stress and total antioxidant capacity in equivalence to Trolox (TEAC), were determined by spectrophotometry. Melatonin was estimated by HPLC. The redox state was analyzed through selecting 68 individuals with Hb SS, 53 with Hb AS and 149 with Hb AA from Brazil’s south and southeast regions. To analyze the influence of epistatic genes on TEAC, melatonin and phenotypical expression, there were selected 17 samples with Hb SS, 30 with Hb AS, and 30 with Hb AA from NOPR. The βS gene haplotypes and -α-3.7 thalassemia were identified through RFLP-PCR and multiplex PCR, respectively. The melatonin serum levels appeared significantly reduced in individuals with Hb SS (P<0.001); and the TBARS and TEAC appeared significantly increased when compared to the control group (P<0.001 and P<0.01, respectively). The correlation between TBARS and TEAC (r=0.51; P=0.04)... (Complete abstract click electronic access below)
116

Perfil oxidativo e bioquímico em pacientes que apresentam anemia falciforme ou traço falciforme / Oxidative and biochemistry profile in sickle cell trait subjects and sickle cell anaemia patients

Manfredini, Vanusa January 2008 (has links)
A Anemia Falciforme (AF) é uma doença autossômica recessiva e, dentre as hemoglobinopatias, é a mais comum das alterações hematológicas hereditárias conhecidas no homem. Sua distribuição é ampla, abrangendo todos os continentes. AF foi a primeira doença caracterizada em nível molecular. É causada por uma mutação no gene beta da globina, produzindo uma alteração estrutural na molécula. No gene da globina beta S, há a substituição de uma base nitrogenada do códon GAG para GTG, resultando na substituição do ácido glutâmico (Glu) pela valina (Val) na posição número seis da globina beta. Essa troca dos aminoácidos que resulta na HbS, altera estruturalmente a molécula e, sob determinadas condições, ocorre a polimerização, trazendo graves conseqüências ao indivíduo sintomático. As espécies reativas de oxigênio (ERO) podem causar profundas lesões em eritrócitos, diminuindo seu período de vida útil, em especial nos pacientes com AF. Acredita-se que, os eritrócitos falcizados estejam sob constante estresse oxidativo e, assim, liberem produtos de degradação da HbS, contribuindo para a progressão da doença. Dessa forma, o dano oxidativo agrava a fisiopatologia dos doentes falciformes. Utilizando técnica espectrofotométrica, foram determinadas as atividades das enzimas antioxidantes catalase (CAT), glutationa peroxidase (GPx) e superóxido dismutase (SOD) e quantificada a glutationa total (GSH) nos eritrócitos dos pacientes. Também determinou-se o dano oxidativo nas proteínas plasmáticas e no hemolisado celular pelo método do carbonil a 360 nm. Os níveis da peroxidação lipídica (MDA) e da vitamina C foram determinados por cromatografia líquida de alta performance (HPLC). Quantificou-se, por fim, os níveis de proteína C reativa ultra-sensível (CRPus) por técnica turbidimétrica. Os participantes da pesquisa (30 HbAA, 28 HbAS e 20 HbSS) foram selecionados junto ao Centro de Apoio do Portador de Anemia Falciforme (CAPAF/RS) e/ou cadastrados no Laboratório de Hematologia da Faculdade de Farmácia (UFRGS). Os doentes falciformes foram identificados por HPLC e confirmados por estudo molecular, utilizando a reação da polimerase em cadeia (PCR). Todos os indivíduos assinaram o termo de consentimento livre e esclarecido e foram submetidos a um questionário nutricional. Os dados obtidos foram expressos como médias ± desvio padrão e analisados utilizando-se o Teste ANOVA de uma via com posterior teste ad hoc. Os resultados do trabalho mostram que os indivíduos traço falciforme (HbAS) apresentam atividade significativamente elevada da CAT em relação aos indivíduos controle. Por outro lado, os doentes falciformes possuem maior atividade da GPx e SOD. O nível de GSH foi proporcionalmente maior nos HbSS seguido dos HbAS e HbAA. Observamos também, dano oxidativo em proteínas plasmáticas, mas não no hemolisado celular. Os HbSS possuem dano oxidativo em proteínas plasmáticas significativamente maior que nos demais grupos. Um aumento significativo da produção de MDA no soro dos HbSS foi observado, como um indicativo do aumento da auto-oxidação dos lipídios sob condições de estresse oxidativo. Os níveis séricos da vitamina C foram significativamente maiores nos HbSS que nos indivíduos controle. A CRPus apresentou-se significativamente elevada nos HbSS em relação aos HbAA. Esses resultados reforçam a idéia de que os pacientes com AF estão sujeitos a um estresse oxidativo crônico, o que contribui para a progressão das complicações dessa anemia hemolítica. Já, os indivíduos traço possuem elevada atividade das defesas antioxidantes capazes de reduzir o dano oxidativo em biomoléculas como proteínas e lipídios. / Sickle cell anaemia (SCA) is an autossomal recessive disease and, among the hemoglobinopaties, is the most common of the known hereditary hematologic alterations in man. Its distribution is ample, enclosing all the continents. Sickle cell anaemia (SCA) was the first disease to be characterized on the molecular level. It is basically a red blood cell (RBC) disorder in which the gene encoding the human β-globin subunit presents a mutation with the resulting replacement of β6 glutamic acid (Glu) by valine (Val). This exchange of the amino acids that results in the HbS modifies the molecule structurally, and under determined conditions, the polymeration occurs, bringing serious consequences to the symptomatic individual. The reactive oxygen species (ROS) can cause deep injuries in erythrocytes, diminishing its period of useful life, specially in patients with sickle cell anaemia. Sickled erythrocytes are under constant oxidative stress and thus liberate products of degradation of the HbS, contributing for the progression of the disease. Because of the oxidative damage aggravates the pathophysiology of sickle cell patients. Using spectrophotometrically technique, catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), were determined the activities of antioxidant enzymes and total glutathione (GSH) quantified in the erythrocytes of the patients. We also determined oxidative damage of plasma proteins and in hemolysate using carbonyl assay at 360 nm. The levels of lipid peroxidation (MDA) and vitamin C were determined by high-performance liquid chromatography (HPLC). Finally, we quantified the levels of high sensitivity Creactive protein (hsCRP) using turbidimetry technique. The participants of the research (30 HbAA, 28 HbAS and 20 HbSS) were selected from Centro de Apoio ao Portador de Anemia Falciforme (CAPAF/RS) and/or registered in cadastre in Laboratório de Hematologia da Faculdade de Farmácia (UFRGS). Sickle cell patients had been identified by HPLC and confirmed by molecular study, using the polymerase chain reaction amplification (PCR). All individuals signed the term of free and clarified assent and were submitted to a nutricional questionnaire. Data were expressed as average ±SD and analyzed using ANOVA test of one way via with the post ad hoc test. Results show that sickle cell trait subjects (HbAS) had significantly high activity of CAT when compared to healthy controls. On the other hand, sickle cell patients had greater activity of GPx and SOD. The GSH levels was proportionally higher in the followed HbSS of the HbAS and HbAA. We also observe oxidative damage in plasma proteins, but not in the cellular hemolysate. HbSS have significantly higher oxidative damage in plasma proteins than other groups. A significant increasing of the production of MDA in the serum of the HbSS was observed as an indicative of the increasing of the auto-oxidation of the lipids under oxidative estress. Serum vitamin C levels in HbSS were significantly higher than healthy control. The hsCRP was presented significantly higher in HbSS than HbAA. These results reinforce the idea that patients with SCA are subjected to chronic oxidative stress, that contributes for the progression of this hemolytic anaemia. On the other hand, sickle cell trait subjects have higher antioxidant defenses that are able to reduce oxidative damage in biological macromolecules such as proteins and lipids.
117

Capacidade antioxidante na Hb S : influência de talassemia alfa, haplótipos do gene βS globina e melatonina /

Shimauti, Eliana Litsuko Tomimatsu. January 2011 (has links)
Resumo: A anemia falciforme (Hb SS), caracterizada por estados de inflamação crônica e eventos de agressão isquêmica e reperfusão pode causar danos oxidativos às macromoléculas biológicas. Os genes epistáticos e os haplótipos do gene da globina βS são possíveis moduladores de variabilidade fenotípica na Hb SS. A melatonina pode atenuar o estresse oxidativo e abrandar a morbidade. O objetivo deste foi analisar a influência de talassemia alfa (-α3.7), haplótipos do gene βS e melatonina na capacidade antioxidante total e expressão fenotípica, em indivíduos com Hb SS e Hb AS. Para avaliar o nível de melatonina sérica foram selecionadas 15 amostras de pacientes com Hb SS e 24 com Hb AA da região noroeste do estado do Paraná (NOPR). A triagem das hemoglobinas foram realizadas por métodos eletroforéticos e cromatográfico, e a caracterização genotípica da Hb S por meio de PCR- RFLP e PCR-AE. As espécies reativas de ácido tiobarbitúrico (TBARS), e a capacidade antioxidante total em equivalência ao Trolox (TEAC) foram determinadas por meio da espectrofotometria. A melatonina foi estimada por meio de HPLC. O estado redox foi analisado selecionando amostras de 68 indivíduos com Hb SS, 53 com Hb AS e 149 com Hb AA, das regiões sul e sudeste do Brasil. Para analisar a influência dos genes epistáticos sobre a TEAC, melatonina e expressão fenotípica, foram selecionadas 17 amostras com Hb SS, 30 com Hb AS, e 30 com Hb AA, da NOPR. O critério para elegebilidade foi ser não fumantes não gestantes, não etilistas e estar na fase estável para os indivíduos com HbSS. Os haplótipos do gene βS e a talassemia -α3.7 foram identificados por meio de PCR-RFLP e PCR multiplex, respectivamente. Os níveis séricos de melatonina apresentaram-se reduzidos nos indivíduos com Hb SS (P<0,001), e os TBARS e TEAC elevados quando comparados a grupo controle (P<0,001 e P<0,01 respectivamente)... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Sickle cell disease (Hb SS), characterized by chronic inflammation and ischemic damage episodes and reperfusion, comprises excessive production of free radicals which can cause oxidative damage to biologic macromolecules. The epistatic genes and the polymorphism of the βS globin gene region are possible modulators of phenotypical variability of sickle cell disease in Hb SS. Melatonin can diminish both the oxidative stress and morbidity. The objective of this study was to analyze the influence of -α-3.7 thalassemia and from βS gene haplotypes on total anti-oxidant capacity, melatonin serum levels and phenotypical expression in individuals with Hb SS and Hb AS. To evaluate melatonin serum level 15 samples with HbSS and 24 with Hb AA from the northwest region of Paraná state (NOPR). The hemoglobin screenings were performed by electrophoretic and chromatographic methods and genotypic characterization of Hb S by PCR- RFLP and PCR-AE. The concentrations of thiobarbituric acid reactive substances (TBARS), used as markers of oxidative stress and total antioxidant capacity in equivalence to Trolox (TEAC), were determined by spectrophotometry. Melatonin was estimated by HPLC. The redox state was analyzed through selecting 68 individuals with Hb SS, 53 with Hb AS and 149 with Hb AA from Brazil's south and southeast regions. To analyze the influence of epistatic genes on TEAC, melatonin and phenotypical expression, there were selected 17 samples with Hb SS, 30 with Hb AS, and 30 with Hb AA from NOPR. The βS gene haplotypes and -α-3.7 thalassemia were identified through RFLP-PCR and multiplex PCR, respectively. The melatonin serum levels appeared significantly reduced in individuals with Hb SS (P<0.001); and the TBARS and TEAC appeared significantly increased when compared to the control group (P<0.001 and P<0.01, respectively). The correlation between TBARS and TEAC (r=0.51; P=0.04)... (Complete abstract click electronic access below) / Orientador: Claudia Regina Bonini Domingos / Coorientador: Eduardo Alves de Almeida / Banca: Hermione Elly Melara de Campos Bicudo / Banca: Paulo César Naoum / Banca: Isaac Lima da Silva Filho / Banca: Octavio Ricci Junior / Doutor
118

Perfil oxidativo e bioquímico em pacientes que apresentam anemia falciforme ou traço falciforme / Oxidative and biochemistry profile in sickle cell trait subjects and sickle cell anaemia patients

Manfredini, Vanusa January 2008 (has links)
A Anemia Falciforme (AF) é uma doença autossômica recessiva e, dentre as hemoglobinopatias, é a mais comum das alterações hematológicas hereditárias conhecidas no homem. Sua distribuição é ampla, abrangendo todos os continentes. AF foi a primeira doença caracterizada em nível molecular. É causada por uma mutação no gene beta da globina, produzindo uma alteração estrutural na molécula. No gene da globina beta S, há a substituição de uma base nitrogenada do códon GAG para GTG, resultando na substituição do ácido glutâmico (Glu) pela valina (Val) na posição número seis da globina beta. Essa troca dos aminoácidos que resulta na HbS, altera estruturalmente a molécula e, sob determinadas condições, ocorre a polimerização, trazendo graves conseqüências ao indivíduo sintomático. As espécies reativas de oxigênio (ERO) podem causar profundas lesões em eritrócitos, diminuindo seu período de vida útil, em especial nos pacientes com AF. Acredita-se que, os eritrócitos falcizados estejam sob constante estresse oxidativo e, assim, liberem produtos de degradação da HbS, contribuindo para a progressão da doença. Dessa forma, o dano oxidativo agrava a fisiopatologia dos doentes falciformes. Utilizando técnica espectrofotométrica, foram determinadas as atividades das enzimas antioxidantes catalase (CAT), glutationa peroxidase (GPx) e superóxido dismutase (SOD) e quantificada a glutationa total (GSH) nos eritrócitos dos pacientes. Também determinou-se o dano oxidativo nas proteínas plasmáticas e no hemolisado celular pelo método do carbonil a 360 nm. Os níveis da peroxidação lipídica (MDA) e da vitamina C foram determinados por cromatografia líquida de alta performance (HPLC). Quantificou-se, por fim, os níveis de proteína C reativa ultra-sensível (CRPus) por técnica turbidimétrica. Os participantes da pesquisa (30 HbAA, 28 HbAS e 20 HbSS) foram selecionados junto ao Centro de Apoio do Portador de Anemia Falciforme (CAPAF/RS) e/ou cadastrados no Laboratório de Hematologia da Faculdade de Farmácia (UFRGS). Os doentes falciformes foram identificados por HPLC e confirmados por estudo molecular, utilizando a reação da polimerase em cadeia (PCR). Todos os indivíduos assinaram o termo de consentimento livre e esclarecido e foram submetidos a um questionário nutricional. Os dados obtidos foram expressos como médias ± desvio padrão e analisados utilizando-se o Teste ANOVA de uma via com posterior teste ad hoc. Os resultados do trabalho mostram que os indivíduos traço falciforme (HbAS) apresentam atividade significativamente elevada da CAT em relação aos indivíduos controle. Por outro lado, os doentes falciformes possuem maior atividade da GPx e SOD. O nível de GSH foi proporcionalmente maior nos HbSS seguido dos HbAS e HbAA. Observamos também, dano oxidativo em proteínas plasmáticas, mas não no hemolisado celular. Os HbSS possuem dano oxidativo em proteínas plasmáticas significativamente maior que nos demais grupos. Um aumento significativo da produção de MDA no soro dos HbSS foi observado, como um indicativo do aumento da auto-oxidação dos lipídios sob condições de estresse oxidativo. Os níveis séricos da vitamina C foram significativamente maiores nos HbSS que nos indivíduos controle. A CRPus apresentou-se significativamente elevada nos HbSS em relação aos HbAA. Esses resultados reforçam a idéia de que os pacientes com AF estão sujeitos a um estresse oxidativo crônico, o que contribui para a progressão das complicações dessa anemia hemolítica. Já, os indivíduos traço possuem elevada atividade das defesas antioxidantes capazes de reduzir o dano oxidativo em biomoléculas como proteínas e lipídios. / Sickle cell anaemia (SCA) is an autossomal recessive disease and, among the hemoglobinopaties, is the most common of the known hereditary hematologic alterations in man. Its distribution is ample, enclosing all the continents. Sickle cell anaemia (SCA) was the first disease to be characterized on the molecular level. It is basically a red blood cell (RBC) disorder in which the gene encoding the human β-globin subunit presents a mutation with the resulting replacement of β6 glutamic acid (Glu) by valine (Val). This exchange of the amino acids that results in the HbS modifies the molecule structurally, and under determined conditions, the polymeration occurs, bringing serious consequences to the symptomatic individual. The reactive oxygen species (ROS) can cause deep injuries in erythrocytes, diminishing its period of useful life, specially in patients with sickle cell anaemia. Sickled erythrocytes are under constant oxidative stress and thus liberate products of degradation of the HbS, contributing for the progression of the disease. Because of the oxidative damage aggravates the pathophysiology of sickle cell patients. Using spectrophotometrically technique, catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), were determined the activities of antioxidant enzymes and total glutathione (GSH) quantified in the erythrocytes of the patients. We also determined oxidative damage of plasma proteins and in hemolysate using carbonyl assay at 360 nm. The levels of lipid peroxidation (MDA) and vitamin C were determined by high-performance liquid chromatography (HPLC). Finally, we quantified the levels of high sensitivity Creactive protein (hsCRP) using turbidimetry technique. The participants of the research (30 HbAA, 28 HbAS and 20 HbSS) were selected from Centro de Apoio ao Portador de Anemia Falciforme (CAPAF/RS) and/or registered in cadastre in Laboratório de Hematologia da Faculdade de Farmácia (UFRGS). Sickle cell patients had been identified by HPLC and confirmed by molecular study, using the polymerase chain reaction amplification (PCR). All individuals signed the term of free and clarified assent and were submitted to a nutricional questionnaire. Data were expressed as average ±SD and analyzed using ANOVA test of one way via with the post ad hoc test. Results show that sickle cell trait subjects (HbAS) had significantly high activity of CAT when compared to healthy controls. On the other hand, sickle cell patients had greater activity of GPx and SOD. The GSH levels was proportionally higher in the followed HbSS of the HbAS and HbAA. We also observe oxidative damage in plasma proteins, but not in the cellular hemolysate. HbSS have significantly higher oxidative damage in plasma proteins than other groups. A significant increasing of the production of MDA in the serum of the HbSS was observed as an indicative of the increasing of the auto-oxidation of the lipids under oxidative estress. Serum vitamin C levels in HbSS were significantly higher than healthy control. The hsCRP was presented significantly higher in HbSS than HbAA. These results reinforce the idea that patients with SCA are subjected to chronic oxidative stress, that contributes for the progression of this hemolytic anaemia. On the other hand, sickle cell trait subjects have higher antioxidant defenses that are able to reduce oxidative damage in biological macromolecules such as proteins and lipids.
119

Crianças e adolescentes portadores de anomia falciforme: os significados das relações estabelecidas com os profissionais no âmbito dos serviços de saúde

Sousa, Eulange de 29 August 2014 (has links)
Submitted by Cláudia Bueno (claudiamoura18@gmail.com) on 2016-03-23T19:39:33Z No. of bitstreams: 2 Tese - Eulange de Sousa - 2014.pdf: 1842524 bytes, checksum: a5108c2cc373e40dfb2dc3c72797efc9 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-03-24T11:23:13Z (GMT) No. of bitstreams: 2 Tese - Eulange de Sousa - 2014.pdf: 1842524 bytes, checksum: a5108c2cc373e40dfb2dc3c72797efc9 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-03-24T11:23:13Z (GMT). No. of bitstreams: 2 Tese - Eulange de Sousa - 2014.pdf: 1842524 bytes, checksum: a5108c2cc373e40dfb2dc3c72797efc9 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-08-29 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / Sickle cell anemia is an inherited disease considered a public health problem in Brazil. In Brazil, it is estimated that there are more than 2 million people affected by some form of this anemia, with 3.500 new cases occurring every year. This dissertation aims to understand the meanings present in the relations established between children and adolescents with sickle cell anemia and professionals within the health services. The methodological choice of this study was the Social Strategic Qualitative Research and it took place at a Teaching Hospital. Data were collected through semi-structured interviews with 3 children, 5 adolescents and 9 health professionals. Data were analyzed through the content analysis technique. From the interviews with children and adolescents, the following categories emerged: the disease, the professionals, and the treatment in other services. From the interviews with health professionals, the following categories emerged: child, adolescent, mother-family, professionals from other services, the disease, and what to do. The research conducted indicated that it is necessary to engage children and adolescents in decisions related to their health-disease process. It also indicated that, in order to achieve it, the health professionals training have to include elements that enable professionals to consider children and adolescents as protagonists in their healthdisease process. In addition, it demonstrated the occurrence of institutional violence in the health treatment that patients with sickle cell anemia receive, as they have their autonomy, their subjectivity and their speech prevented and annulled. / A Anemia falciforme é uma doença hereditária considerada um problema de saúde pública no Brasil. Estima-se que existem, no Brasil, mais de 2 milhões de pessoas afetadas por alguma forma desta anemia, com uma ocorrência de 3.500 novos caso por ano. Este trabalho tem por objetivo compreender os significados presentes nas relações estabelecidas entre as crianças e adolescentes portadores de anemia falciforme e os profissionais no âmbito dos serviços de saúde. Esta pesquisa foi realizada tendo como opção metodológica a Pesquisa Social Estratégica de abordagem qualitativa, e como local de estudo optou-se por um hospital de ensino. Os dados foram obtidos por meio de entrevistas semiestruturadas com três crianças, cinco adolescentes e nove profissionais de saúde. Os dados foram analisados pela técnica de análise de conteúdo. A partir das entrevistas com as crianças e adolescentes, emergiram as seguintes categorias: doença, os profissionais e o atendimento em outros serviços. Das entrevistas com os profissionais, emergiram as categorias: criança, adolescente, mãe–família, profissionais de outros serviços, a doença e o que fazer. O estudo realizado indicou que é necessário envolver as crianças e adolescentes nas decisões relativas a seu processo saúde-doença e que a formação de profissionais de saúde deve incluir elementos que os instrumentalizem no sentido de considerar crianças e adolescentes como protagonistas em seu processo saúde-doença. Indicou também a ocorrência de violência institucional no atendimento que os portadores de anemia falciforme recebem, pois têm sua autonomia, sua subjetividade e sua fala impedidas e anuladas.
120

INHIBITION OF ERYTHROCYTE BAND 3 TYROSINE PHOSPHORYLATION: CHARACTERIZATION OF A NOVEL THERAPY FOR SICKLE CELL DISEASE AND MALARIA

Panae Noomuna (10716546) 29 April 2021 (has links)
While the molecular defect that cause sickle cell disease has well been established, the cause of vaso-occlusive crisis remains elusive and largely debated upon. Majority of studies have linked the painful episodes to polymerization of sickle hemoglobin following its deoxygenation. The variability of the disease symptoms among patients, compounds efforts for a holistic therapy. Hydroxyurea, a stimulator of Hb F induction and a widely used treatment, has ameliorated the complication of SCD but it is only effective in 50% of the patients. Expression of Hb F lowers the content of Hb S in blood and hence reduces oxidative stress caused by Hb S denaturation. Sickle cell disease severity depends on several factors. Most importantly, the ability of red cell to sickle dominates all other determinants. While deoxygenation of sickle hemoglobin may be inevitable, the duration with which the red cell remains in the deoxygenated state can be manipulated. Deoxygenation is a transient process that when compared to the time taken to develop the long filaments of deoxyhemoglobin to causes severe sickling, the red cell would have been cycled back to the lungs and re-oxygenated to restore the healthy conditions of the cell. In fact, if sickle cells would flow as fast as healthy erythrocytes, the detrimental impacts of sickling such as vaso-occlusive crisis, would not be a concern for this disease. Unfortunately, the unstable sickle hemoglobin undergoes denaturation through auto-oxidation, which imposes oxidative stress to the cells. The oxidative stress inhibits erythrocytes tyrosine phosphatases, a course which subsequently impair their constitutive action against the tyrosine kinases. In the end, a net tyrosine phosphorylation state in the red cell membrane proteins, most notably the transmembrane protein band 3, succeeds. Band 3 tyrosine phosphorylation abrogates the protein’s interaction with ankyrin and spectrin-actin cytoskeleton, hence the cytoskeleton loses its major anchorage to the membrane thus engendering membrane destabilization. A destabilized erythrocyte sheds membrane fragments in form of microvesicles/microparticles and discharges free hemoglobin into the extra cellular matrix. In consequence, the microparticles power initiation of coagulation cascade through activation of thrombin, while free Hb inflicts inflammation, scavenges nitric oxide which is necessary for vasodilation and induces further oxidative stress within the microvasculature, and activates expression of adhesion receptors on the endothelium. Taken together, these events culminate in entrapment of red cells (not naming leucocytes and platelets) in the microvasculature, blockade of blood vessels and further damage of erythrocytes through prolonged deoxygenated state thus terminating in tissue injury, strokes, and organ damage, amid vaso-occlusive episodes which always require hospitalization and extensive medical care for survival. Band 3 tyrosine phosphorylation and membrane weakening is not unique just to SCD, but also a druggable target for malaria. Malaria, a disease that is touted as the evolutionary cause of sickle cell disease, surprisingly thrives through the same mechanism. Briefly, malaria parasite consumes hemoglobin for its DNA synthesis, and in the process generate reactive oxygen species from denatured hemoglobin that feeds into the oxidative stress which triggers band 3 tyrosine phosphorylation. In this case however, a destabilized membrane offers perfect conditions for merozoites’ (malaria daughter parasites) egress/exit out of the cell to begin infecting other red cells. Ultimately, the ensuing anemia and organ dysfunction leads to patient’s death. Treatment of diseased cells with imatinib and other Syk inhibitors effectively reversed membrane weakening. A stabilized membrane not only survives longer in circulation to alleviate SCD symptoms but also traps and starves malaria parasite leading to termination of the parasitic infection. With band 3 tyrosine phosphorylation at center stage, this dissertation explores the above events in an effort to unveil a novel therapy for sickle cell and malaria diseases. First, the therapeutic strategy regarding SCD is discussed in detail beginning with non-transfused patients and ending in additional mechanistic study on inactivation of the principal erythrocyte’s protein tyrosine phosphatase 1 B, PTP1B. The dissertation then provides an initial proof of concept on efficacy of imatinib in treatment of malaria as a monotherapy and its efficacy when used in a triple combination therapy with the standard of care treatment. Finally, I outline an alternative possible mechanism of action of quinine against malaria.

Page generated in 0.1167 seconds