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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.
271

Trombose da veia porta em crianças e adolescentes : deficiência das proteínas C, S e Antitrombina e pesquisa das mutações fator V Leiden, G20210A da Protrombina e C677T da Metileno-tetraidrofolato redutase

Pinto, Raquel Borges January 2000 (has links)
Objetivo: A trombose da veia porta é uma causa importante de hiper-tensão porta em crianças e adolescentes, porém, em uma proporção importante dos casos, não apresenta fator etiológico definido. O objetivo desse estudo é determinar a freqüência de deficiência das proteínas inibidoras da coagulação – proteínas C, S e antitrombina − e das mutações fator V Leiden, G20210A no gene da protrombina e C677T da metileno-tetraidrofolato redutase em crianças e adolescentes com trom-bose da veia porta, definir o padrão hereditário de uma eventual deficiência das pro-teínas inibidoras da coagulação nesses pacientes e avaliar a freqüência da deficiên-cia dessas proteínas em crianças e adolescentes com cirrose. Casuística e Métodos: Foi realizado um estudo prospectivo com 14 crianças e adolescentes com trombose da veia porta, seus pais (n = 25) e dois gru-pos controles pareados por idade, constituídos por um grupo controle sem hepato-patia (n = 28) e um com cirrose (n = 24). A trombose da veia porta foi diagnosticada por ultra-sonografia abdominal com Doppler e/ou fase venosa do angiograma celíaco seletivo. A dosagem da atividade das proteínas C, S e antitrombina foi determinada em todos os indivíduos e a pesquisa das mutações fator V Leiden, G20210A da pro-trombina e C677T da metileno-tetraidrofolato redutase, nas crianças e adolescentes com trombose da veia porta, nos pais, quando identificada a mutação na criança, e nos controles sem hepatopatia. Resultados: Foram avaliados 14 pacientes caucasóides, com uma média e desvio padrão de idade de 8 anos e 8 meses ± 4 anos e 5 meses e do diagnóstico de 3 anos e 8 meses ± 3 anos e seis meses. Metade dos pacientes pertenciam ao gênero masculino. O motivo da investigação da trombose da veia porta foi hemorra-gia digestiva alta em 9/14 (64,3%) e achado de esplenomegalia ao exame físico em 5/14 (35,7%). Anomalias congênitas extra-hepáticas foram identificadas em 3/14 (21,4%) e fatores de risco adquiridos em 5/14 (35,7%) dos pacientes. Nenhum pa-ciente tinha história familiar de consangüinidade ou trombose venosa. A deficiência das proteínas C, S e antitrombina foi constatada em 6/14 (42,9%) (p < 0,05 vs con-troles sem hepatopatia), 3/14 (21,4%) (p > 0,05) e 1/14 (7,1%) (p > 0,05) pacientes com trombose da veia porta, respectivamente. A deficiência dessas proteínas não foi identificada em nenhum dos pais ou controles sem hepatopatia. A mutação G20210A no gene da protrombina foi identificada em um paciente com trombose da veia porta e em um controle sem hepatopatia (p = 0,999), mas em nenhum desses foi identificado a mutação fator V Leiden. A mutação C677T da metileno-tetraidrofo-lato redutase foi observada na forma homozigota, em 3/14 (21,4%) dos pacientes com trombose da veia porta e em 5/28 (17,9%) controles sem hepatopatia (p = 0,356). A freqüência da deficiência das proteínas C, S e antitrombina nos pacientes com cir-rose foi de 14/24 (58,3%), 7/24 (29,2%) e 11/24 (45,8%), respectivamente (p < 0,05 vs controles sem hepatopatia), sendo mais freqüente nos pacientes do subgrupo Child-Pugh B ou C, que foi de 11/12 (91,7%), 5/12 (41,7%) e 9/12 (75%), respectivamente (p < 0,05 vs controles sem hepatopatia). Conclusões: A deficiência de proteína C foi freqüente nas crianças e adolescentes com trombose da veia porta e não parece ser de origem genética. A deficiência de proteína S, antitrombina e as presenças das mutações G20210A da protrombina e C677T da metileno-tetraidrofolato redutase foram observadas mas não apresentaram diferença estatística significativa em relação ao grupo controle sem hepatopatia. O fator V Leiden não foi identificado. Os resultados deste estudo sugerem que a deficiência da proteína C pode ocorre como conseqüência da hiper-tensão porta. Os distúrbios pró-trombóticos hereditários não parecem apresentar um papel importante em relação à trombose nas crianças e adolescentes estudadas. / Objective: Portal vein thrombosis is a major cause of portal hypertension in children and adolescents; yet, its etiology is not clearly defined in a considerable number of cases. The present study aims at determining the prevalence of blood coagulation disorders – protein C, protein S and antithrombin – and factor V Leiden, G20210A prothrombin, and C677T methylenetetrahydrofolate reductase mutations in children and adolescents with portal vein thrombosis, as well as assessing the hereditary character of these disorders in these patients, and also evaluating the prevalence of blood coagulation disorders in children and adolescents with cirrhosis. Study design: A prospective study was carried out, including children and adolescents with portal vein thrombosis (n = 14), their parents (n = 25), two age-matched control groups, one without liver disease (n = 28), and another with cirrhosis (n = 24). Portal vein thrombosis was diagnosed through abdominal Doppler ultrasonography and/or venous phase of selective coeliac angiograms. The activity of protein C, protein S and antithrombin was evaluated for all individuals; the presence of factor V Leiden, G20210A prothrombin, and C677T methylenetetrahydrofolate reductase gene mutations was investigated in children and adolescents with portal vein thrombosis, in parents when their respective children presented any of these mutations, and in the control group without liver disease. Results: 14 Caucasian patients were assessed. The mean and standard deviation for age were 8 years and 8 months ± 4 years and 5 months while the mean and standard deviation for diagnosis were 3 years and 8 months ± 3 years and six months. Half of the patients were males. Initial clinical manifestations upon diagnosis were digestive hemorrhage in 9/14 (64.3%) and splenomegaly on physical examination in 5/14 individuals (35.7%). Patients presented extrahepatic anomalies in 3/14 (21.4%) and acquired risk factors in 5/14 (35.7%) of the cases. None of the patients had a family history of consanguinity or venous thrombosis. The frequency of protein C, protein S and antithrombin deficiency was observed in 6/14 (42.9%) (p < 0.05 vs. controls without liver disease), 3/14 (21.4%) (p > 0.05) and 1/14 (7.1%) (p > 0.05) of patients, respectively. None of the portal vein thombosis patients or controls presented protein C, S or antithrombin deficiency. One portal vein patient and one control (p = 0.999) presented G20210A prothrombin mutation. None of these patients presented the factor V Leiden. The homozygous form of C677T methylenetetrahydrofolate reductase mutation was observed in 3/14 patients with portal vein thrombosis (21.4%) and in 5/28 controls (17.9%) (p = 0.356). The frequency of coagulation inhibitor deficiency was high in cirrhotic patients (14/24 (58.3%) PC, 7/24 (29.2%) PS and 11/24 (45.8%) AT; p < 0.05 vs. controls), especially in Child-Pugh B and C patients (11/12 (91.7%) PC, 5/12 (41.7%) PS and 9/12 (75%) AT; p < 0.05 vs. controls). Conclusions: Protein C deficiency was frequent in children and adolescents with portal vein thrombosis and does not seem to be an inherited condition. Protein S and antithrombin deficiency, and G20210A prothrombin and C677T methylenetetrahydrofolate reductase mutations were observed but did not present statistically significant differences when compared to the controls without liver disease. Factor V Leiden was not observed. The results suggest the protein C deficiency may originates from portal hypertension. The hereditary prothrombotic disorders do not seem to play a vital role in thrombosis in children and adolescents with portal vein thrombosis.
272

Trombose da veia porta em crianças e adolescentes : deficiência das proteínas C, S e Antitrombina e pesquisa das mutações fator V Leiden, G20210A da Protrombina e C677T da Metileno-tetraidrofolato redutase

Pinto, Raquel Borges January 2000 (has links)
Objetivo: A trombose da veia porta é uma causa importante de hiper-tensão porta em crianças e adolescentes, porém, em uma proporção importante dos casos, não apresenta fator etiológico definido. O objetivo desse estudo é determinar a freqüência de deficiência das proteínas inibidoras da coagulação – proteínas C, S e antitrombina − e das mutações fator V Leiden, G20210A no gene da protrombina e C677T da metileno-tetraidrofolato redutase em crianças e adolescentes com trom-bose da veia porta, definir o padrão hereditário de uma eventual deficiência das pro-teínas inibidoras da coagulação nesses pacientes e avaliar a freqüência da deficiên-cia dessas proteínas em crianças e adolescentes com cirrose. Casuística e Métodos: Foi realizado um estudo prospectivo com 14 crianças e adolescentes com trombose da veia porta, seus pais (n = 25) e dois gru-pos controles pareados por idade, constituídos por um grupo controle sem hepato-patia (n = 28) e um com cirrose (n = 24). A trombose da veia porta foi diagnosticada por ultra-sonografia abdominal com Doppler e/ou fase venosa do angiograma celíaco seletivo. A dosagem da atividade das proteínas C, S e antitrombina foi determinada em todos os indivíduos e a pesquisa das mutações fator V Leiden, G20210A da pro-trombina e C677T da metileno-tetraidrofolato redutase, nas crianças e adolescentes com trombose da veia porta, nos pais, quando identificada a mutação na criança, e nos controles sem hepatopatia. Resultados: Foram avaliados 14 pacientes caucasóides, com uma média e desvio padrão de idade de 8 anos e 8 meses ± 4 anos e 5 meses e do diagnóstico de 3 anos e 8 meses ± 3 anos e seis meses. Metade dos pacientes pertenciam ao gênero masculino. O motivo da investigação da trombose da veia porta foi hemorra-gia digestiva alta em 9/14 (64,3%) e achado de esplenomegalia ao exame físico em 5/14 (35,7%). Anomalias congênitas extra-hepáticas foram identificadas em 3/14 (21,4%) e fatores de risco adquiridos em 5/14 (35,7%) dos pacientes. Nenhum pa-ciente tinha história familiar de consangüinidade ou trombose venosa. A deficiência das proteínas C, S e antitrombina foi constatada em 6/14 (42,9%) (p < 0,05 vs con-troles sem hepatopatia), 3/14 (21,4%) (p > 0,05) e 1/14 (7,1%) (p > 0,05) pacientes com trombose da veia porta, respectivamente. A deficiência dessas proteínas não foi identificada em nenhum dos pais ou controles sem hepatopatia. A mutação G20210A no gene da protrombina foi identificada em um paciente com trombose da veia porta e em um controle sem hepatopatia (p = 0,999), mas em nenhum desses foi identificado a mutação fator V Leiden. A mutação C677T da metileno-tetraidrofo-lato redutase foi observada na forma homozigota, em 3/14 (21,4%) dos pacientes com trombose da veia porta e em 5/28 (17,9%) controles sem hepatopatia (p = 0,356). A freqüência da deficiência das proteínas C, S e antitrombina nos pacientes com cir-rose foi de 14/24 (58,3%), 7/24 (29,2%) e 11/24 (45,8%), respectivamente (p < 0,05 vs controles sem hepatopatia), sendo mais freqüente nos pacientes do subgrupo Child-Pugh B ou C, que foi de 11/12 (91,7%), 5/12 (41,7%) e 9/12 (75%), respectivamente (p < 0,05 vs controles sem hepatopatia). Conclusões: A deficiência de proteína C foi freqüente nas crianças e adolescentes com trombose da veia porta e não parece ser de origem genética. A deficiência de proteína S, antitrombina e as presenças das mutações G20210A da protrombina e C677T da metileno-tetraidrofolato redutase foram observadas mas não apresentaram diferença estatística significativa em relação ao grupo controle sem hepatopatia. O fator V Leiden não foi identificado. Os resultados deste estudo sugerem que a deficiência da proteína C pode ocorre como conseqüência da hiper-tensão porta. Os distúrbios pró-trombóticos hereditários não parecem apresentar um papel importante em relação à trombose nas crianças e adolescentes estudadas. / Objective: Portal vein thrombosis is a major cause of portal hypertension in children and adolescents; yet, its etiology is not clearly defined in a considerable number of cases. The present study aims at determining the prevalence of blood coagulation disorders – protein C, protein S and antithrombin – and factor V Leiden, G20210A prothrombin, and C677T methylenetetrahydrofolate reductase mutations in children and adolescents with portal vein thrombosis, as well as assessing the hereditary character of these disorders in these patients, and also evaluating the prevalence of blood coagulation disorders in children and adolescents with cirrhosis. Study design: A prospective study was carried out, including children and adolescents with portal vein thrombosis (n = 14), their parents (n = 25), two age-matched control groups, one without liver disease (n = 28), and another with cirrhosis (n = 24). Portal vein thrombosis was diagnosed through abdominal Doppler ultrasonography and/or venous phase of selective coeliac angiograms. The activity of protein C, protein S and antithrombin was evaluated for all individuals; the presence of factor V Leiden, G20210A prothrombin, and C677T methylenetetrahydrofolate reductase gene mutations was investigated in children and adolescents with portal vein thrombosis, in parents when their respective children presented any of these mutations, and in the control group without liver disease. Results: 14 Caucasian patients were assessed. The mean and standard deviation for age were 8 years and 8 months ± 4 years and 5 months while the mean and standard deviation for diagnosis were 3 years and 8 months ± 3 years and six months. Half of the patients were males. Initial clinical manifestations upon diagnosis were digestive hemorrhage in 9/14 (64.3%) and splenomegaly on physical examination in 5/14 individuals (35.7%). Patients presented extrahepatic anomalies in 3/14 (21.4%) and acquired risk factors in 5/14 (35.7%) of the cases. None of the patients had a family history of consanguinity or venous thrombosis. The frequency of protein C, protein S and antithrombin deficiency was observed in 6/14 (42.9%) (p < 0.05 vs. controls without liver disease), 3/14 (21.4%) (p > 0.05) and 1/14 (7.1%) (p > 0.05) of patients, respectively. None of the portal vein thombosis patients or controls presented protein C, S or antithrombin deficiency. One portal vein patient and one control (p = 0.999) presented G20210A prothrombin mutation. None of these patients presented the factor V Leiden. The homozygous form of C677T methylenetetrahydrofolate reductase mutation was observed in 3/14 patients with portal vein thrombosis (21.4%) and in 5/28 controls (17.9%) (p = 0.356). The frequency of coagulation inhibitor deficiency was high in cirrhotic patients (14/24 (58.3%) PC, 7/24 (29.2%) PS and 11/24 (45.8%) AT; p < 0.05 vs. controls), especially in Child-Pugh B and C patients (11/12 (91.7%) PC, 5/12 (41.7%) PS and 9/12 (75%) AT; p < 0.05 vs. controls). Conclusions: Protein C deficiency was frequent in children and adolescents with portal vein thrombosis and does not seem to be an inherited condition. Protein S and antithrombin deficiency, and G20210A prothrombin and C677T methylenetetrahydrofolate reductase mutations were observed but did not present statistically significant differences when compared to the controls without liver disease. Factor V Leiden was not observed. The results suggest the protein C deficiency may originates from portal hypertension. The hereditary prothrombotic disorders do not seem to play a vital role in thrombosis in children and adolescents with portal vein thrombosis.
273

Avaliação da veia oftálmica superior por meio do Doppler colorido nas diferentes formas e estágios da orbitopatia de Graves / Evaluation of the superior ophthalmic vein by color Doppler in different forms and stages of Graves Orbitopathy

Helio Angotti Neto 28 January 2011 (has links)
INTRODUÇÃO: A orbitopatia de Graves é uma doença autoimune cujas manifestações clínicas ocorrem por infiltração tecidual inflamatória. Apresenta estágio ativo inicial e estágio sequelar posteriormente, podendo se manifestar nas formas clínicas miogênica ou lipogênica. A inflamação da órbita pode gerar importante congestão, agravando manifestações clínicas e comprometendo o sucesso da terapia específica em alguns pacientes. O objetivo deste trabalho é a avaliação da congestão orbitária feita pelo estudo das características do fluxo sanguíneo na veia oftálmica superior, por meio do Doppler colorido de órbitas, nos grupos de pacientes com orbitopatia de graves em fase ativa, em fase sequelar miogênica e em fase sequelar lipogênica, além do grupo controle. MÉTODOS: Estudo transversal prospectivo realizado entre maio de 2006 e abril de 2008 no Serviço de Órbita do HCFMUSP. Noventa órbitas de 46 pacientes com orbitopatia de Graves foram incluídas, assim como 38 órbitas de 20 pacientes do grupo controle. Foi feito exame oftalmológico completo e avaliação pelo DCO em todos os pacientes. Pacientes com orbitopatia de Graves foram divididos em grupos com doença em atividade e doença em estágio sequelar nas apresentações miogênicas ou lipogênicas. O sentido, as velocidades máxima e mínima do fluxo sanguíneo na veia oftálmica superior, e o intervalo entre as mesmas, foram aferidos. Os achados foram comparados entre os diferentes grupos e analisados também em relação à restrição muscular, exoftalmometria, escore de atividade clínica, idade, sexo, lado estudado, comorbidades e tabagismo. RESULTADOS: Foi encontrada diferença no sentido do fluxo sanguíneo da veia oftálmica superior (p<0,001), na velocidade máxima (p=0,001), na velocidade mínima (p=0,002) e no intervalo entre a velocidade máxima e a mínima do mesmo (p<0,001) entre os grupos de estudo. A velocidade máxima do fluxo sanguíneo apresentou correlação com a restrição muscular (p=0,003), o escore de atividade clínica (p<0,001) e a exoftalmometria (p=0,015), enquanto a velocidade mínima correlacionou-se com restrição muscular (p<0,001) e escore de atividade clínica (p=0,006). CONCLUSÕES: Há diferença mensurável na velocidade e no sentido do fluxo sanguíneo da veia oftálmica superior entre pacientes dos diferentes grupos de estudo / INTRODUCTION: Graves orbitopathy is an autoimmune disease whose clinical manifestations are secondary to inflammatory tissue infiltration. It presents an initial active stage and a later latent stage, and can manifest myogenic or lipogenic clinical forms. Inflammation of the orbit can generate significant congestion, worsening clinical manifestations and limiting the success of specific therapy in some patients. The objective of this study is to evaluate orbital congestion studying the characteristics of blood flow in the superior ophthalmic vein with the color Doppler in groups of patients with Graves Orbitopathy in active stage, lipogenic latent stage and myogenic latent stage, and patients from the control group. METHODS: Transversal study made between May 2006 and April 2008 in the Orbit Department of University of São Paulo Medical School. Ninety orbits from 46 patients with Graves orbitopathy and 38 orbits from 20 patients of the control group were included. All patients underwent complete ophthalmological exams including color Doppler of the orbits. Patients with Graves orbitopathy were divided in active stage, latent lipogenic stage and latent myogenic stage groups. The direction of venous blood flow in the superior ophthalmic vein and its maximum and minimum velocities - including the interval between them - were measured. The results were compared among the groups and analyzed also in relation to muscular restriction, exophthalmometry, clinical activity score, age, sex, studied orbit side, comorbidities and use of tobacco. RESULTS: There was difference in blood flow direction of the superior ophthalmic vein (p<0,001), blood flow maximum speed (p=0,001), blood flow minimum speed (p=0,002) and blood flow speed interval (p<0,001) among the groups of this study. Blood flow maximum speed presented correlation with muscle restriction (p=0,003), clinical activity score (p<0,001) and exophthalmometry (p=0,015). Blood flow minimum speed presented correlation with muscle restriction (p<0,001) and clinical activity score (p=0,006). CONCLUSIONS: There are measurable difference in speed and direction of blood flow in the superior ophthalmic vein among patients of the different groups of this study
274

Současné možnosti ovlivnění dlouhodobé průchodnosti koronárních bypassů / Current possibilities of influence long-term patency of coronary artery bypass grafts

Skalský, Ivo January 2014 (has links)
The main complication of aortocoronary reconstruction with vein grafts is restenosis in the course of time. The aim was to assess the effect of a periadventitial polyester system releasing sirolimus on intimal hyperplasia of autologous grafts. The controlled-release system comprises a polyester mesh coated with a sirolimus-eluting copolymer of L lactic acid and ε-caprolactone system designed to be wrapped around an autologous venous graft during its implantation. In vitro sirolimus release and its effects on smooth muscle and endothelial cells were assessed. In vitro, the copolymer-coated polyester mesh released sirolimus over a period of 6 weeks. Mesh-eluted sirolimus inhibited the growth of smooth muscle and endothelial cells in seven-day in vitro experiments. After seven days of sirolimus release from the mesh, smooth muscle and endothelial cell counts decreased by 29% and 75%, respectively, with the cells maintaining high viability. We implanted v. jugularis ext. into a. carotis communis in rabbits. The vein graft was either intact, or was wrapped with a pure polyester mesh, or with a sirolimus-releasing mesh. Three and six weeks after surgery, the veins were subjected to standard histological staining and the thicknesses of the tunica intima, the media and the intima-media complex were...
275

Estudo da atividade dos sulfatos de condroitina e glucosamina na formação de vasos sanguíneos em modelos in vitro e in vivo

BORBA, Fernanda Katharine de Souza Lins 29 February 2012 (has links)
Submitted by (lucia.rodrigues@ufrpe.br) on 2016-06-01T16:45:23Z No. of bitstreams: 1 Fernanda Katharine de Souza Lins Borba.pdf: 4059966 bytes, checksum: cce20c494a8d5b3926e4508d0ff50750 (MD5) / Made available in DSpace on 2016-06-01T16:45:23Z (GMT). No. of bitstreams: 1 Fernanda Katharine de Souza Lins Borba.pdf: 4059966 bytes, checksum: cce20c494a8d5b3926e4508d0ff50750 (MD5) Previous issue date: 2012-02-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Chondroitin Sulfate (CS) and Glucosamine Sulfate (GS) are functional constituents of vertebrate tissues. GS is an amino sugar and CS is part of the glucosaminoglycans group (GAGs). Studies have suggested CS and GS to have anti-inflammatory properties, however it has also been shown that these compounds promote scarring and proliferation of fibroblasts, which express molecules important for blood vessel growth (angiogenesis). This study was aimed at evaluating the effects of CS and GS on in vitro models regarding cell viability (cytotoxicity - MTT), proliferation (BrdU incorporation) and differentiation (tubulogenesis in Matrigel support) on human umbilical vein endothelial cells (HUVEC line). In vivo angiogenesis was also evaluated in (1) extraembryonic membranes of Gallus domesticus (number of chorioallantoic vessels - CAM assay and vitelinic YSM assay; and fractal geometry analysis); (2) and subcutaneous tissue of adult mice (Mus muscullus) by hemoglobin quantification (Spectroscopy) in Gelfoam implants. In the HUVEC assay, both CS and GS (1-3000 g/mL) displayed partial cytotoxic effect (~50% viability), but only in the highest tested concentrations (3000 and 1000 g/mL). It was observed that CS (3 g/mL), but not GS, promoted proliferation and tubulogenesis of HUVEC in 40% (P < 0.05) and 64% (P < 0.05), respectively, relative to control (RPMI-1640 medium). These effects did not significantly differ from the respective 28% and 53% promoted by the well known angiogenic growth factor FGF-2 (50 ng/mL). In the in vivo vasculoangiogenesis YSM assay on 2 to 4-day old embryos, GS (0.001-0.1mg/disk) and, to a lesser extent, CS (0.030-0.1mg/disk) increased the amount of vessels relative to control (P < 0.05). The effects of administration of CS and GS (0.1mg/disk) did not differ from what was observed in groups treated with 50 ng/mL FGF2. In the CAM angiogenesis assay on 6 to 8-days old embryos, again both CS and GS increased the amount of vessels relative to control, but only in concentrations as high as 2.0 mg/disk. This effect was no different from what was observed in groups treated with 50 ng/mL FGF2. The pro-angiogenic effects of CS (2 mg/disk) in embryonary angiogenesis were confirmed in the advanced angiogenesis of mice: only the group treated with CS (2 mg/implant) displayed a significant increase in the amount of blood vessels, expressed as hemoglobin content (0.52 ± 0.08g/dL), relative to control (vehicle; PBS; 0.20 ± 0.07 g/dL). This pro-angiogenic effect was no different than that of FGF2 (0.53 ± 0.1g/dL). The in vitro and in vivo results indicate the pro-angiogenic properties of CS and GS. However, CS (GAG) was the more effective compound in the tests performed. As a constituent of proteoglycans, it is suggested that CS exerts its effects by interacting with FGF and other angiogenic factors in the extracellular matrix, stabilizing the receptor, and thus positively modulating the pro-angiogenic signal in endothelial cells. While the cellular mechanisms underlying CS and GS activity demand more specific research, there is an evident potential therapeutic use for both compounds in clinical situations, such as those related to vascular discrepancy. / Sulfato de glucosamina (SG) e Sulfato de condroitina (SC) são constituintes funcionais dos tecidos de vertebrados. O SG é um aminoaçúcar e o SC integra o grupo das glicosaminoglicanas (GAG). Estudos apontam propriedades antiinflamatórias do SC e SG, e demonstram ainda que essas substâncias promovem a cicatrização e a proliferação de fibroblastos, os quais expressam moléculas que atuam na formação de vasos sanguíneos (angiogênese). Os objetivos deste estudo foram avaliar a ação do SC e SG em modelos in vitro sobre a viabilidade (citotoxicidade pelo MTT), proliferação (incorporação por BrdU) e diferenciação (tubulogênese em suporte matrigel) na linhagem de células endoteliais de veia umbilical humana (HUVEC). Também se investigou a angiogênese in vivo: (1) em membranas anexas de embriões de Gallus domesticus (número de vasos corioalantóides - ensaio da CAM, e vitelínicos – ensaio da YSM; e análise por geometria fractal); (2) e no tecido subcutâneo de camundongos adultos por meio de quantificação da hemoglobina em implantes de Gelfoam. No ensaio com HUVEC, SC e SG (1-3000 g/mL) exerceram efeito citotóxico parcial (~50% de viabilidade), e somente nas respectivas maiores concentrações (3000 e 1000 g/mL). Verificou-se que o SC (3 g/mL), mas não o SG, estimulou a proliferação e a tubulogênese de HUVEC em 40% (p < 0,05) e em 64% (p < 0,05) respectivamente, em relação ao controle (meio RPMI-1640). Estes efeitos não diferiram estatisticamente dos 28% e 53%, respectivamente, promovidos pelo bem conhecido fator de crescimento angiogênico FGF-2 (50 ng/mL). No ensaio de vasculo-angiogênese na YSM de embriões de 2-4 dias de idade o SG (0,001-0,1mg/disco) principalmente, e o SC (0,030-0,1mg/disco) aumentaram o número de vasos em relação ao grupo controle (p < 0,05). Os efeitos da administração de SC e SG (0,1 mg/disco) não diferiram do observado no grupo tratado com 50 ng/mL de FGF-2. No ensaio de angiogênese na CAM de embriões de 6-8 dias de idade, ambos, SC e SG também elevaram o número de vasos em relação ao controle na concentração elevada de 2,0 mg/disco. Este efeito também não diferiu do observado no grupo exposto a 50 ng/mL de FGF- 2. O efeito pró-angiogênico do SC (2 mg/disco) na angiogênese embrionária foi confirmado na angiogênese avançada de camundongos adultos. Apenas o grupo que recebeu SC (2 mg/implante) mostrou um aumento significativo de vasos sanguíneos, expresso como conteúdo de hemoglobina (0,52 ± 0,08g/dL), comparado ao controle (veículo; PBS; 0,20 ± 0,07 g/dL). Este efeito pró-angiogênico não diferiu do obtido com FGF2 (0,53 ± 0.1g/dL). Os resultados in vitro e in vivo demonstram as propriedades pró-angiogênicas do SC e SG, contudo o SC (GAG) foi o mais efetivo nos ensaios. Como um constituinte de proteoglicanas, o SC sugere exercer seus efeitos pela interação com o FGF e outros fatores angiogênicos na matriz extracelular, estabilizando-os nos receptores e modulando assim, positivamente, o sinal pró-angiogênico nas células endoteliais. Embora mecanismos celulares subjacentes à atividade de SC e SG demandem mais estudos, evidencia-se um potencial papel terapêutico das duas substâncias em situações clínicas relacionadas à defasagem vascular.
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Estudo comparativo do diagnóstico de edema macular secundário a oclusão de ramo da veia central da retina pela biomicroscopia de mácula, angiofluoresceinografia e tomografia de coerência óptica / Comparison of optic coherence tomography, macular biomicroscopy and fluorescein angiography for macular edema secondary to branch retinal vein occlusion

Alexandre Grobberio Pinheiro 04 October 2007 (has links)
As Oclusões Venosas da Retina são complicações do sistema vascular retiniano com grande potencial de impacto no sentido da visão. As oclusões Venosas são classificadas de acordo com a anatomia da região acometida e podem ser divididas em oclusão de ramo e da veia central da retina. O edema macular é a principal causa de baixa acuidade visual na Oclusão de Ramo da Veia Central da Retina (OVR). Sua detecção, localização e classificação são cruciais para a prevenção e tratamento da perda visual na OVR. A Biomicrospia Macular e a Angiofluoresceinografia são os métodos tradicionais de avaliação do edema macular na OVR, a Tomografia de Coerência Óptica (TCO) é uma tecnologia nova, que permite uma avaliação objetiva da morfologia macular. O objetivo primário do presente estudo foi avaliar, em uma mesma população, a acurácia dos métodos de diagnóstico do edema macular na OVR através da análise de três quesitos, aumento da espessura macular e da sua localização, presença de cistos intra-retinianos e a presença de descolamento seroso macular (DSM). Indivíduos com OVR foram selecionados com base nos achados fundoscópicos da doença e com tempo de história da doença entre três e vinte quatro meses. Todos os sujeitos foram submetidos a exames com o Stratus OCT (TCO), Angiofluoresceinografia digital (Angio) e o exame da biomicroscopia macular com lente de Volk de 78 D (BM) dentro do período de uma semana, além de exame oftalmológico completo. As medidas utilizadas para avaliação da acurácia diagnóstica foram o índice de concordância Kappa e a sensibilidade. Dos 32 indivíduos inicialmente avaliados, 8 foram posteriormente excluídos por não cumprirem os critérios de inclusão ou de exclusão, restando 24 indivíduos para análise. Na avaliação da espessura macular, a concordância entre BM e a TCO foi substancial e significante para a detecção do aumento da espessura macular com Kappa = 0,778 (p < 0,001) e a sensibilidade foi 95,5%. Na comparação entre a BM e a TCO para a detecção de cistos intra-retinianos, a concordância foi fraca com Kappa = 0,250 (p = 0,066) e a sensibilidade foi 57,9 %. A concordância entre a Angio e a TCO para os cistos foi pobre e não significante com Kappa = 0,124 (p = 0,237) e a sensibilidade foi 58,7 %. Houve uma correlação significante entre a presença de extravasamento na angiofluoresceinografia e a presença de cistos intra-retinianos na TCO (p=0,042). Na avaliação do DSM a concordância entre a BM e a TCO foi fraca com Kappa = 0,314 (p = 0,062) e a sensibilidade foi 60%, não houve concordância entre a Angio e a TCO para a detecção do DSM com Kappa = 0 e sensibilidade de 0%, e também não houve correlação significante entre a presença de descolamento seroso na TCO e a presença de extravasamento na angiofluoresceinografia (p=0,615). Os dados obtidos no presente estudo sugeriram que o Stratus OCT têm acurácia superior para a detecção dos cistos intra-retinianos e do descolamento seroso macular, se comparado à biomicroscopia macular e à angiofluoresceinografia / Retinal Vein Occlusions are complications of the retinal vascular system that can cause a great impact on vision. The Vein Occlusions are classified according to the anatomy of the affected region and can be categorized as: branch retinal vein occlusion and central retinal vein occlusion. Macular edema is the main cause for low visual acuity in Branch Retinal Vein Occlusion (BRVO). Its detection, location and classification are crucial for the prevention and treatment of vision loss in BRVO. Both Macular Biomicroscopy and Angiofluoresceinography are traditional methods for the evaluation of the macular edema in BRVO; the Optical Coherence Tomography (OCT) is a new technology that allows for an objective evaluation of macular morphology. The main objective of the present study was to evaluate, among the same population, the accuracy of the diagnostic methods of macular edema in BRVO through the analysis of three items: the increase of macular thickness and its location, the presence of intraretinal cysts, and the presence of serous macular detachment. Patients with BRVO were selected according to the fundoscopic findings of the disease and a disease history of three to twenty-four months. All of the individuals underwent exams with the Stratus OCT, digital Angiofluoresceinography (Angio) and a macular biomicroscopy with a 78D Volk lens (MB), within a period of one week, as well as a complete ophthalmologic exam. The parameters used in the evaluation of the diagnostic accuracy were sensitivity and the kappa coefficient. Of the 32 subjects who were initially evaluated, 8 were later excluded since they did not meet inclusion or exclusion criteria. The remaining 24 subjects were analyzed. In the evaluation of macular thickness, the concordance between the MB and the OCT was substantial and significant in the detection of the increase in macular thickness, with Kappa = 0.778 (p<0.001) and a sensitivity of 95.5%. When comparing the MB and the OCT in the detection of intraretinal cysts, the concordance was fair, with Kappa = 0.250 (p = 0.066) and a sensitivity of 57.9%. The concordance between the Angio and the OCT for cysts detection was poor and non significant, with Kappa = 0.124 (p = 0.237) and a sensitivity of 58.7%. There was a significant correlation between the presence of leakage in the angiofluoresceinography and the presence of intraretinal cysts in the OCT (p = 0.042). In the evaluation of the SMD, the concordance between the MB and the OCT was fair, with Kappa = 0.314 (p = 0.062) and a sensitivity of 60% an there was no concordance between the Angio and the OCT in the detection of SMD, with Kappa = 0 and sensitivity of 0%. There was also no significant correlation between the presence of serous detachment in the OCT and the presence of leakage in the angiofluoresceinography (p = 0.615). The results obtained in the present study suggest that Stratus OCT is more accurate to the detection of intraretinal cysts and serous macular detachment than macular biomicroscopy with a 78D Volk lens, and by angiofluoresceinography
277

Caractérisation des oligomères β-amyloïdes cérébraux et vasculaires impliqués dans la maladie d’Alzheimer / Caracterization of cerebral and vascular amyloid- β oligomer involved in Alzheimer’s disease

Boutonnet, Marie-Charlotte 16 December 2013 (has links)
Depuis quelques années, les oligomères du peptide Aβ sont identifiés comme étant responsables du déclenchement de la pathologie alors que les dépôts amyloïdes sont des conséquences aggravantes de la pathologie. Cependant, les formes oligomériques d’Aβ impliquées dans la pathologie ainsi que l’origine de ces peptides sont toujours débattues. Notre objectif principal était d’identifier des signatures Aβ oligomériques cérébrales et vasculaires et de déterminer si nous pouvions interférer avec ces signatures pour modifier le décours de la pathologie. Nous avons réalisé des analyses biochimiques qualitative des formes d’Aβ dans des échantillons de cerveau et de vaisseaux issus de patients atteints de la MA et de souris transgéniques modèle de la MA. Nous avons montré qu’une même forme Aβ oligomérique (17-18 kDa) est impliquée dans le développement de la pathologie cognitive chez l’homme et chez la souris APP/PS1. Une signature Aβ oligomérique vasculaire spécifique a été observée dans les vaisseaux périphériques et plus particulièrement la veine porte hépatique des souris APP/PS1. De plus, un traitement pharmacologique ciblant l’expression des protéines de transport de l’Aβ a permis de restaurer les profils Aβ oligomériques contrôles dans le cerveau des souris APP/PS1 tout en « chargeant » la veine porte des mêmes souris en Aβ oligomérique. Ces résultats montrent que les signatures Aβ vasculaires et cérébrales sont intimement liées. De plus, nos travaux mettent l’accent sur une possible intervention thérapeutique agissant sur les formes Aβ cérébrales et vasculaires. / Alzheimer's disease (AD) is a complex disorder of the central nervous system that affects an increasing number of people worldwide due to the overall aging of the human population. Vascular factors and mechanisms have emerged as an area of key importance. Accumulating evidence indicates that pre-fibrillar aggregates, specifically the low-molecular weight oligomers of Aβ peptide, are responsible for the synaptic dysfunction and neuronal loss that occur in AD pathology. But, these oligomeric forms implicated in the pathology are currently under debate. Our primary goal was to identify cerebral and vascular oligomeric signatures. Secondly, we try to interfere with these signatures in order to modify the evolution of AD. We realize qualitative analyses of cerebral and vascular oligomers Aβ by western-blot. Vascular and cerebral tissues were extracted from AD patients and from a transgenicmouse model of AD. We demonstrate that the same oligomer Aβ (17-18 kDa) is implicated in the cognitive impairment for patients and APP/PS1 mouse. A specific vascular signature of oligomer Aβ was detected in peripheral vessels and particularly in portal vein from liver of APP/PS1 mouse. Moreover, pharmacological treatment targeting clearance of soluble Aβ restored the control signature of oligomer Aβ in the brain of APP/PS1 mouse. This configurational change was associated with an increase of oligomer Aβ in portal vein from liver. These results show that cerebral and vascular oligomeric signatures were closely linked. Finally, our work emphasizes potential therapeutic strategies for AD by targeting cerebrals and vasculars oligomers Aβ.
278

Characterization Of Structural And Non-structural Proteins Of Positive Sense, Single-stranded RNA Plant Viruses

Mathur, Chhavi 06 1900 (has links) (PDF)
In the present thesis, two positive sense single-stranded RNA viruses have been used as models to understand the structure and function of viral-encoded proteins. One of them, Pepper Vein Banding Virus (PVBV; genus Potyvirus; family Potyviridae) is a flexuous, rod-shaped virus that encodes for a polyprotein of size ~340 kDa. The polyprotein undergoes proteolytic processing by viral-encoded proteases, of which Nuclear Inclusion-a Protease (NIa-Pro) is the major protease. It is a serine-like cysteine protease which cleaves between a Q/A or Q/S, present in the context of the heptapeptide recognition sequence. The temporal regulation of intermediates and mature proteins released by NIa-Pro cleavage is crucial for a successful infection. In the present study, histidine-tagged NIa-Pro, Viral Protein genome-linked (VPg), and the cleavage site mutant (E191A) VPg-Pro were over-expressed in E. coli and purified. The protease activity of NIa-Pro was monitored using an HPLC-based protease assay developed using a peptide substrate. NIa-Pro protease activity was found to get modulated upon interaction with VPg and upon undergoing phosphorylation. Both these events have been found to involve the face of NIa-Pro which contains the solvent-exposed Trp143. Mutational studies and molecular dynamics analyses provide evidence that this residue is buried upon interaction of NIa-Pro with VPg, and any perturbation of its orientation influences the active site Cys151 via an extensive interaction network. This interaction was found to enhance the velocity of NIa-Pro protease activity, especially if the two domains were present in trans (VPg+Pro). In addition, the main-chain –NH2 group of Trp143 was found to be hydrogen-bonded to the side chain –OH group of Ser129, the residue which was identified to undergo phosphorylation by host plant kinases. Interestingly, when the two domains were present in cis (E191A VPg-Pro), no phosphorylation was observed. Mutations of Ser129 (to phosphorylation-mimic Asp or phosphorylation-deficient Ala residues) which affected this H-bond were found to disturb Trp143 and Cys151 orientation, which drastically reduced the protease activity of NIa-Pro. Within the polyprotein, VPg is present at the N-terminus of NIa-Pro and the cleavage site between them is suboptimal (E/A). In the present study, VPg-Pro was shown to be covalently linked to the genomic RNA present in the virions. Interestingly, during purification, VPg could only be purified from the soluble when it was expressed at the N-terminus of NIa-Pro. A series of bioinformatics and biophysical analysis of VPg showed that PVBV VPg, like other potyviral VPgs, exists as a molten-globule. Moreover, while VPg was shown to harbour the Walker motifs, it was found to exhibit an ATPase activity only when it was present with the NIa-Pro (especially in cis). Lys47 and Asp88:Glu89 were found crucial for optimal activity. Over all the results demonstrated that there is a reciprocal modulation of structure and function of the VPg and NIa-Pro domains. These results can explain the possible significance of an impeded cleavage rate between the two domains of VPg-Pro during PVBV infection. The precursor, VPg-Pro, could offer the advantage of evading the inhibitory phosphorylation of NIa-Pro by the host, as well as drive certain viral processes by virtue of its ATPase activity. And subsequent cleavage of the domains and their trans interaction could offer a higher turnover rate which might assist sufficient CP production required for viral morphogenesis. Another virus, Tobacco Streak Virus (TSV) that belongs to the Ilarvirus genus of the Bromoviridae family is a spherical virus which forms pleiomorphic icosahedral virus particles. It has a tripartite genome and each RNA is encapsidated individually. In the present thesis, TSV was used as a model to understand the properties of its structural protein-the coat protein (CP), with the aim of deciphering TSV assembly process. Thus, the CP gene from TSV RNA 3 was cloned and over-expressed in E. coli. The coat protein thus expressed formed virus-like particles (VLPs), which could be disassembled into dimers using high CaCl2 concentrations. Reassembly of VLPs was possible from dimers even in the absence of any nucleic acid. Mutational analysis of the N-terminal disordered domain showed that 26 amino acid residues from the amino-terminus could be crucial for capsid heterogeneity while, zinc-binding domain was essential for assembly. Overall, the present study shows that the flexible W-C loop of PVBV NIa-Pro, the disordered N-terminal region of PVBV VPg and the disordered N-terminal region of TSV CP harbour residues crucial for regulation of protein function. Such regulatory elements would ultimately allow viruses to maintain a smaller protein number, and thus a smaller genome size.
279

Estrutura do nervo alveolar inferior em fetos humanos da 19ª a 36ª semana de vida intrauterina / Inferior alveolar nerve structure in human fetuses from 19th to 36th weeks of intrauterine life

Ricardo Eustaquio da Silva 11 December 2012 (has links)
O nervo alveolar inferior (Nai), o mais espesso ramo do nervo mandibular (V par craniano), está funcionalmente relacionado à inervação da mandíbula e dentes inferiores, além de parte dos tecidos moles circunjacentes. Seu estudo morfológico, sobretudo em mandíbulas adultas, foi sistematicamente realizado, contudo, sem ainda haver um consenso definitivo para o seu padrão de ramificação. Desse modo, considerando-se a importância em se demonstrar um modelo de constituição básica para o Nai, realizou-se o presente estudo em fetos humanos da 19ª a 36ª semana de vida intrauterina. Foram utilizados 86 hemimandíbulas, de ambos os sexos, em que se avaliou o padrão morfológico intraósseo do Nai e de seus ramos, seus envoltórios conjuntivos e suas relações com as estruturas vasculares, utilizando-se de microdissecção e microscopia eletrônica de varredura (MEV). Relativamente ao padrão morfológico do segmento intramandibular do Nai, foram propostos 4 tipos de ramificação: Tipo I (16%), onde o Nai emite 3 ramos principais, os nervos alveolares inferiores posterior (Naip), médio (Naim) e anterior (Naia); Tipo II (34%), semelhante ao anterior, porém ausente o Naim; Tipo III (30%), semelhante ao primeiro, porém ausentes Naim e o Naia; e o Tipo IV (20%), a forma clássica do Nai, onde somente o Naia se ramifica a partir dele. Verificou-se uma série de conexões entre todos os feixes nervosos, sobretudo entre o Naip e o Nai, sendo que os ramos dentais e peridentais partem, em sua maioria, do Naip, Naim e Naia. Sobre os envoltórios conjuntivos, verificou-se que se espessam à medida que o feto se desenvolve, notando também a presença de uma bainha neurovascular comum a envolver o feixe vasculonervoso alveolar inferior. Quanto ao posicionamento da artéria alveolar inferior, adjacente ao forame da mandíbula, cruza o feixe nervoso, em sua maioria, pela face medial (41%) ou pela lateral (55%), para logo em seguida alcançar sua posição definitiva sobre a face superior do feixe nervoso. Quanto às veias alveolares inferiores, em número de 1 a 3, posicionam-se posteromedialmente às outras estruturas do feixe vasculonervoso. Para a veia de Serres, observada em todos os espécimes e envolta por um canal ósseo, propôs-se a terminologia veia paramandibular. / The inferior alveolar nerve (Nai), the thickest branch of the mandibular nerve (V pair of cranial nerve), is functionally related to jaw and lower teeth innervation as well as, being part of the surrounding smooth tissue. The Nai morphology has been systematically studied in mandible of adults however, no definitive consensus has been reached in relation to its branched pattern. Therefore, this study was been performed in 19 to 36 week-gestation fetuses, due to the importance of determining a basic model of Nai as available data refers only to its arrangement in adults. Micro dissection and Scanner Electron Microscopy (MEV) were performed on 86 human hemi-mandibles of both sexes in order to evaluate the morphological intraosseous pattern of Nai and its branches, its connective tissue and their relationship with vascular structures. In connection with the morphological pattern of intramandibular segment of Nai, four types of branches were proposed: Type I (16%) where Nai give rise to 3 main branches: posterior inferior alveolar nerve (Naip), medium (Naim), and anterior (Naia); Type II (34%), similar to Type I but Naim was absent; Type III (30%), similar to the first, however Naim and Naia were absent; and type IV (20%),the classic form of Nai, from which only Naia was raised. A series of connections was verified among all of the nervous bundles, especially between Nai and Naip. besides dental and periodontal branches commonly arising from Naip, Naim and Naia. In relation with the connective tissues, it was shown that they became thicker as the fetuses are developing; at this stage it was also noted one neurovascular sheath covering nerve bundles and blood vessels. Relatively to the inferior alveolar artery position, adjacent to mandible foramen, it can, frequently, cross the nerve bundle through medial (41%) or lateral surface (55%), reached after its final position on the superior surface of nerve bundle; the inferior alveolar veins (1 to 3), are posterior-medially positioned to the neurovascular bundle other structures. The terminology paramandibular vein was proposed to the Serres vein observed in all specimens studied which was surrounded by bone channel.
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The effects of celastrol on endothelial cells survival and proliferation

Vu, Minh Quan 08 1900 (has links)
Introduction: Coronary artery bypass grafts are most commonly performed using saphenous vein grafts to complement the internal thoracic artery. The saphenous vein will remain popular despite its lower patency rate because it is easily accessible and lengthy enough to perform multiple bypasses. Therefore, several approaches have been studied, with the common goal of finding the optimal conditions that reduce graft failure. They include novel harvest techniques, new preservation preparations, innovative genetic therapies and experimental drugs. We believe a pharmacological pre-conditioning with an anti-oxidative and anti-inflammatory drug during the crucial time of harvest may spark beneficial survival response from the endothelial cells. One particular compound is Celastrol, an HSP90 inhibitor, which displays those antioxidant and anti-inflammatory properties. Methods: Human umbilical vein endothelial cells (HUVEC) were pretreated with various concentrations of Celastrol (10-10M, 10-8M and 10-6M). In order to reproduce oxidative stress found in ischemia/reperfusion, cells were exposed to hydrogen peroxide for a short and extended period (1h and 24h). To mimic storage condition encountered in clinical settings, cells were also exposed in heparinized normal saline. The viability was assessed by LIVE/DEAD assay. As for migrative and proliferative properties, scratch tests were performed. Finally, various protective intracellular pathways were evaluated by Western blot. Results: This study shows that pre-treatment with Celastrol promotes survival in HUVEC submitted to oxidative stress. Notable improvement in cellular viability was detected as early as 1 hour after oxidative stress (H2O2 4 mM), 76.6% vs 66.1% (p=0.005). Significant survival benefits are also reported after prolonged oxidative stress (H2O2 0.5 mM for 24 hours); viability was 93.7% vs 76.9% (p=0.001) for Cel 10- 8 M and 96.6% vs 76.9% (p=0.002) for Celastrol 10-10M when compared to the vehicle. Celastrol, however, did not significantly affect viability of HUVEC stored in heparinized normal saline. Celastrol at 10-6 M promotes faster and more complete wound closure compared to the vehicle or to lower dosages. Celastrol triggers early activation of the RISK pathway, inducing activation of both Akt and ERK1/2 within the first 15 minutes of treatment. Celastrol also induces the expression of HSP70 and HO-1, effectors of the Heat Shock Response and the anti-oxidative response respectively. Conclusion: Pre-treatment by Celastrol provides survival benefits in endothelial cells under oxidative stress. It also stimulates endothelial cell proliferation and migration, promoting faster and more complete re-endothelialisation. Celastrol can potentially be used as an additive to storage solutions to limit endothelial injury and promote graft protection. / Introduction: La chirurgie de pontage coronarien requiert, dans la grande majorité des cas, l’utilisation de l’artère mammaire interne en combinaison avec un ou des greffons provenant de la grande veine saphène. Malgré le taux de perméabilité inférieur aux artères, la veine saphène reste un choix populaire de conduit en raison de son accessibilité et de sa longueur. De ce fait, le greffon veineux devient la cible de multiples approches et le sujet de nombreuses études visant à optimiser sa perméabilité. Celles-ci incluent le raffinement des techniques de prélèvement, les solutions de préservations, les agents pharmacologiques ainsi que la thérapie génique. Il est davantage intéressant de combiner les approches afin de joindre leurs bénéfices, comme, par exemple, ajouter un agent pharmacologique à une solution de préservation. Un agent potentiel serait le Celastrol, connu pour être un inhibiteur du HSP90 et possède des propriétés antioxydantes et anti-inflammatoires. Méthodologie: Des cellules endothéliales humaines provenant de la veine ombilicale (HUVEC) sont pré-conditionnées à de multiples concentrations de Celastrol (10-10M, 10-8M and 10-6M) pendant une heure avant d’être soumises aux conditions de stress. Pour reproduire les conditions per-opératoires de prélèvement, les cellules endothéliales ont été préservées dans du salin (NS) héparinisé. Pour mimer le stress secondaire à l’ischémie/reperfusion, les cellules ont aussi été soumises à diverses concentrations de H2O2. Une analyse de la viabilité cellulaire fut conduite par le test de LIVE/DEAD. La capacité de ré-endothélialisation est étudiée grâce à l’épreuve de scratch test. Les voies intracellulaires de survie telles que le RISK pathway (Akt, ERK1/2), le Heat shock response (HSP70) et la réponse anti-oxydante (via l’activité de HO-1) ont été examinées par immunoblot. Résultats: Les résultats démontrent que la préservation des cellules endothéliales dans du NS héparinisé est associée à une augmentation de la mortalité comparativement au milieu de culture (20.4% vs 1.9%, p=0.004). Toutefois, un traitement au Celastrol n’affecte pas significativement la survie des cellules endothéliales dans le NS héparinisé. Le stress oxydatif induit aussi une augmentation de la mortalité, et ce à dose-dépendante. Suivant un court stress 6 oxydatif (H2O2 4 mM), un pré-traitement au Celastrol 10-10M est associé à une meilleure viabilité comparativement au véhicule (76.6% vs 66.1%, p=0.005). Lorsque soumises à un stress oxydatif prolongé (H2O2 0.5 mM pendant 24h), les HUVEC pré-traitées au Celastrol à 10-8M et 10-10M démontrent une amélioration significative de la viabilité, 93.7% vs 76.9% (p=0.001) et 93.6% vs 76.9% (p=0.002) respectivement. Quant à la ré-endothélialisation, un traitement au Celastrol 10- 6M est associé à une fermeture plus rapide et complète comparativement au véhicule. Un court traitement au Celastrol active précocement les kinases de la voie de RISK (Akt et ERK). Le traitement induit aussi l’expression de HSP70 et HO-1 qui reste soutenue jusqu’à 48 heures posttraitement. Conclusion: Le Celastrol active plusieurs voies de protection intracellulaire tels que le RISK pathway, le Heat Shock Response et la réponse antioxydante via l’activité de HO-1. En corrélation avec cette réponse, il améliore la survie des cellules endothéliales dans un milieu oxydatif. Le Celastrol promeut aussi une ré-endothélialisation plus complète et rapide. Cette étude met en valeur les bénéfices potentiels du Celastrol sur les cellules endothéliales. Afin d’optimiser la protection du greffon, le Celastrol pourrait donc être considéré comme agent adjuvant à une solution de préservation.

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