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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.
101

Avaliação eletroneurográfica comparativa precoce de pacientes com plexopatia braquial obstétrica / Electroneurography for early prognostic assessment of obstetrical brachial plexopathy

Heise, Carlos Otto 01 October 2003 (has links)
O desenvolvimento de um método eficiente de avaliação prognóstica precoce seria de grande utilidade na seleção de lactentes com plexopatia braquial obstétrica para cirurgias de reconstrução do plexo braquial. Realizamos uma eletroneurografia bilateral em 33 bebês com plexopatia braquial obstétrica entre 10 e 60 dias de vida. Foram avaliadas e comparadas lado a lado as amplitudes dos potenciais de ação musculares compostos dos nervos axilar, musculocutâneo, radial proximal, radial distal, mediano e ulnar. Os bebês foram seguidos clinicamente até os seis meses de vida, quando foram submetidos a uma avaliação da força de vários grupos musculares e a uma prova funcional. Uma redução da amplitude do potencial de ação muscular composto em qualquer nervo do membro acometido maior ou igual a 90% da amplitude do potencial do membro sadio correlacionou-se com um resultado clínico ruim aos seis meses de idade (p < 0,01). A acurácia prognóstica da eletroneurografia foi de 91% para as lesões do tronco superior, 97% para as lesões do tronco médio e 100% para as lesões do tronco inferior. Nossos resultados indicam que a eletroneurografia parece ser um instrumento útil na avaliação prognóstica precoce de pacientes com plexopatia braquial obstétrica / Early prognostic assessment of obstetric brachial plexopathies would be a major step for rational selection of infants for brachial plexus surgery. We performed bilateral electroneurography of Axillary, Musculocutaneous, proximal Radial, distal Radial, Median and Ulnar nerves in 33 babies (age 10 - 60 days) with obstetrical brachial plexus lesions in order to compare the amplitude of compound muscle action potentials (CMAPs). The babies were followed up for six months and the outcome was classified according to muscle power score and functional performance. A CMAP amplitude reduction in any nerve of the injured side superior or equal to 90% of CMAP amplitude of the normal side was related to an unfavorable clinical result at age of six months (p < 0,01). The prognostic accuracy of electroneurography was 91% for the upper trunk, 97% for the middle trunk and 100% for the lower trunk. Our results indicate that electroneurography seems to be a useful tool for very early prognostic assessment of obstetric brachial plexopathies
102

Novo método radiográfico para a determinação de estenose do canal cervical / New method for radiografic determination of cervical stenosis

Bornholdt, Gustavo Campelo 07 October 2015 (has links)
INTRODUÇÃO: Estenose do canal cervical consiste na diminuição do diâmetro sagital do canal cervical e está associada com maior risco de lesões neurológicas decorrentes de trauma cervical. Nos esportes de colisão, a estenose do canal cervical consiste em um importante parâmetro na decisão de retorno ao esporte após neuropraxia da medula cervical e após determinadas lesões do plexo braquial. Os métodos atualmente disponíveis para avaliação de estenose do canal cervical em atletas são muito caros (ex: por ressonância nuclear magnética) ou pouco precisos (métodos radiográficos). Este estudo avaliou um novo método radiográfico para determinação de estenose do canal cervical, comparando-o com medições realizadas em cadáveres, medida por ressonância nuclear magnética do canal cervical e do espaço disponível para a medula (SAC/SACD) e com o método radiográfico consagrado na literatura para determinação de estenose do canal cervical, o índice de Torg (IT). MÉTODOS: A população do estudo foram 20 homens entre 16 e 35 anos de idade. Os sujeitos realizaram uma ressonância nuclear magnética da coluna cervical para determinação do SAC/SACD e radiografias cervicais em perfil e antero-posterior para determinação do IT e do novo método radiográfico proposto, o diâmetro corrigido do canal cervical (DCCC). Para determinar o DCCC, foi utilizada uma barra de metal de 100 mm, acoplada verticalmente na linha média cervical, utilizando os processos espinhosos das vertebras cervicais como referência. Obtidos o diâmetro sagital da imagem do canal cervical e o comprimento da imagem da barra de metal na radiografia, e conhecendo o tamanho real da barra de metal, o diâmetro real do canal medular pôde ser estimado matematicamente com o uso do teorema de Tales. Os resultados obtidos para o DCCC foram comparados com valores encontrados em estudos com cadáveres, foi avaliada a concordância entre DCCC e o diâmetro médio-sagital do canal cervical aferido por ressonância magnética (DCRM) e os métodos radiográficos (DCCC e IT) foram correlacionados com o SAC/SACD. Os cálculos foram realizados nos níveis C3 a C7, além das médias de C3 a C6 [DCCC (MDCCC), IT (MTorg) e SAC/SACD (MSAC/MSACD)]. RESULTADOS: Os valores obtidos pelo DCCC (média do MDCCC: 15.29 mm) foram compatíveis com os valores descritos em estudos de medida direta. A correlação entre DCCC e SAC/SACD foi superior à correlação entre IT e SAC/SACD, sendo de 0.7025 para MDCCC e MSACD contra 0.5473 para MTorg e MSACD. O teste de concordância entre os valores absolutos para DCCC e DCRM evidenciou valores mais elevados na medida por DCCC, sendo média de 1.84 mm maior para MDCCC em relação a média de C3 a C6 pelo DCRM. CONCLUSÕES: O Diâmetro Corrigido do Canal Cervical apresentou valores semelhantes aos encontrados em estudos com medida direta em cadáveres e apresentou correlação com SAC/SACD superior ao IT / INTRODUCTION: Cervical spinal stenosis is the diminution of the anteroposterior diameter of the spinal canal and it is associated with increased risk of neurological injury from cervical trauma. In collision sports, the cervical canal stenosis is an important parameter in the return to play decision after cervical cord neuropraxia and after some brachial plexus injuries. The methods currently available for evaluation of cervical canal stenosis in athletes are expensive (eg, nuclear magnetic resonance) or imprecise (radiographic methods). This study evaluated a new radiographic method for determination of cervical canal stenosis, comparing it to measurements performed on cadavers, measurement by magnetic resonance imaging of the cervical canal and space available for the cord (SAC/SACD) and the consecrated radiographic method for determining cervical spinal stenosis, Torg ratio(TI). METHODS: The study population were 20 men between 16 and 35 years. The subjects underwent a magnetic resonance imaging of the cervical spine to determine the SAC/SACD and cervical radiographs to determine the IT and the proposed new radiographic method, called corrected cervical canal diameter (DCCC). To determine the DCCC, a 100 mm metal bar was used vertically over the cervical midline, using the spinous processes of the cervical vertebrae as reference. Got the radiographic diameter of the medullary canal and the length of the metal bar image on the radiograph , and knowing the actual size of the metal bar , the actual diameter of the spinal canal could be estimated mathematically with the simple use of the theorem of Thales. The results for the DCCC were compared with values found in cadavers studies, the agreement between DCCC and the mid-sagittal diameter of the cervical canal measured by magnetic resonance imaging (DCRM) was calculated and radiographic methods (DCCC and IT) were correlated with SAC/SACD. Calculations were performed individually for C3 to C7 and averages of C3 to C6 [DCCC (MDCCC), IT (MTorg) and SAC/SACD (MSAC/ MSACD)]. RESULTS: The values obtained by DCCC (average MDCCC: 15:29 mm) were consistent with the values described in studies using direct measurement. The correlation between DCCC and SAC/SACD was higher than the correlation between IT and SAC/SACD, being 0.7025 for MDCCC and MSACD and 0.5473 for MTorg and MSACD. The agreement between absolute values for DCCC and DCRM showed higher values for DCCC, which average 1.84 mm greater for MDCCC compared to the average of C3 to C6 for DCRM. CONCLUSIONS: The Fixed Diameter of the Cervical Canal showed similar values to those found in studies with direct measurement from cadavers and correlated with SAC/SACD better than IT
103

Caracterización biológica y clínica del riesgo trombótico y hemorrágico de pacientes con fibrilación auricular no valvular bajo tratamiento anticoagulante oral.

Gallego Hernanz, María Pilar 21 March 2013 (has links)
El elevado riesgo tromboembólico y hemorrágico en la fibrilación auricular (FA) es altamente heterogéneo y condiciona la morbi-mortalidad de la FA. La anticoagulación oral previene eventos trombóticos y mortalidad, pero conlleva ciertos riesgos. Por ello, los pacientes son estratificados según escalas de riesgo, que se intentan refinar adicionando otros marcadores. Para evaluar su utilidad pronóstica, puntuamos según las escalas CHA2DS2-VASc y HAS-BLED a pacientes consecutivos, anticoagulados de forma estable. Además determinamos los títulos de troponina T (hsTnT) e interleukina 6 ultrasensibles (hsIL6), y el índice tobillo brazo (ITB). La escala CHA2DS2-VASc predice eventos cardiovasculares y mortalidad; la escala HAS-BLED no solo es útil en la valoración del riesgo hemorrágico sino que también muestra valor predictivo de eventos cardiovasculares y mortalidad. Los valores de hsTnT y los de hsIL6 añaden información pronóstica, mejorando el índice de discriminación integrado de ambas escalas. El ITB resultó predictor de eventos trombóticos y hemorrágicos / The high thrombotic risk determines the atrial fibrillation morbi-mortality. Oral anticoagulation results in stroke and mortality prevention, at the expense of bleeding-related risk. These risks are highly heterogeneous, reason why patients are stratified according to risk scores, refined by specific biomarkers. In order to evaluate their prognostic value, we recruited consecutive patients, steady on oral anticoagulation, in whom CHA2DS2-VASc and HAS-BLED scores were calculated. In addition levels of high sensitivity troponin T and interleukin 6 (hsTnT and hsIL6 respectively) were determined, and the ankle brachial index (ABI) measured. The CHA2DS2-VASc score predicts cardiovascular events and mortality; HAS-BLED score is not only useful to assess bleeding risk but also shows predictive value for cardiovascular events and mortality. In addition levels of both hsTnT and hsIL6 provided prognostic information, improving the integrated discrimination index of both scores. Abnormal ABI was an independent predictor for all-cause mortality and major bleeding.
104

Biomarkers for cardiovascular risk prediction in people with type 2 diabetes

Price, Anna Helen January 2017 (has links)
Introduction: Type 2 diabetes continues to be one of the most common non-communicable diseases worldwide and complications due to type 2 diabetes, such as cardiovascular disease (CVD) can cause severe disability and even death. Despite advances in the development and validation of cardiovascular risk scores, those used in clinical practice perform inadequately for people with type 2 diabetes. Research has suggested that particular non-traditional biomarkers and novel omics data may provide additional value to risk scores over-and-above traditional predictors. Aims: To determine whether a small panel of non-traditional biomarkers improve prediction models based on a current cardiovascular risk score (QRISK2), either individually or in combination, in people with type 2 diabetes. Furthermore, to investigate a set of 228 metabolites and their associations with CVD, independent of well-established cardiovascular risk factors, in order to identify potential new predictors of CVD for future research. Methods: Analyses used the Edinburgh Type 2 Diabetes Study (ET2DS), a prospective cohort of 1066 men and women with type 2 diabetes aged 60-75 years at baseline. Participants were followed for eight years, during which time 205 had a cardiovascular event. Additionally, for omics analyses, four cohorts from the UCL-LSHTM-Edinburgh-Bristol (UCLEB) consortium were combined with the ET2DS. Across all studies, 1005 (44.73%) participants had CVD at baseline or experienced a cardiovascular event during follow-up. Results: In the ET2DS, higher levels of high sensitivity cardiac troponin (hs-cTnT) and N-terminal pro-brain natriuretic peptide (NT-proBNP) and lower levels of ankle brachial pressure index (ABI) were associated with incident cardiovascular events, independent of QRISK2 and pre-existing cardiovascular disease (odds ratios per one SD increase in biomarker 1.35 (95% CI: 1.13, 1.61), 1.23 (1.02, 1.49) and 0.86 (0.73, 1.00) respectively). The addition of each biomarker to a model including just QRISK2 variables improved the c-statistic, with the biggest increase for hs-cTnT (from 0.722 (0.681, 0.763) to 0.732 (0.690, 0.774)). When multiple biomarkers were considered in combination, the greatest c-statistic was found for a model which included ABI, hs-cTnT and gamma-glutamyl transpeptidase (0.740 (0.699, 0.781)). In the combined cohorts from the UCLEB consortium, a small number of high-density lipoprotein (HDL) particles were found to be significantly associated with CVD: concentration of medium HDL particles, total lipids in medium HDL, phospholipids in medium HDL and phospholipids in small HDL. These associations persisted after adjustment for a range of traditional cardiovascular risk factors including age, sex, blood pressure, smoking and HDL to total cholesterol ratio. Conclusions: In older people with type 2 diabetes, a range of non-traditional biomarkers increased predictive ability for cardiovascular events over-and-above the commonly used QRISK2 score, and a combination of biomarkers may provide the best improvement. Furthermore, a small number of novel omics biomarkers were identified which may further improve risk scores or provide better prediction than traditional lipid measurements such as HDL cholesterol.
105

Novo método radiográfico para a determinação de estenose do canal cervical / New method for radiografic determination of cervical stenosis

Gustavo Campelo Bornholdt 07 October 2015 (has links)
INTRODUÇÃO: Estenose do canal cervical consiste na diminuição do diâmetro sagital do canal cervical e está associada com maior risco de lesões neurológicas decorrentes de trauma cervical. Nos esportes de colisão, a estenose do canal cervical consiste em um importante parâmetro na decisão de retorno ao esporte após neuropraxia da medula cervical e após determinadas lesões do plexo braquial. Os métodos atualmente disponíveis para avaliação de estenose do canal cervical em atletas são muito caros (ex: por ressonância nuclear magnética) ou pouco precisos (métodos radiográficos). Este estudo avaliou um novo método radiográfico para determinação de estenose do canal cervical, comparando-o com medições realizadas em cadáveres, medida por ressonância nuclear magnética do canal cervical e do espaço disponível para a medula (SAC/SACD) e com o método radiográfico consagrado na literatura para determinação de estenose do canal cervical, o índice de Torg (IT). MÉTODOS: A população do estudo foram 20 homens entre 16 e 35 anos de idade. Os sujeitos realizaram uma ressonância nuclear magnética da coluna cervical para determinação do SAC/SACD e radiografias cervicais em perfil e antero-posterior para determinação do IT e do novo método radiográfico proposto, o diâmetro corrigido do canal cervical (DCCC). Para determinar o DCCC, foi utilizada uma barra de metal de 100 mm, acoplada verticalmente na linha média cervical, utilizando os processos espinhosos das vertebras cervicais como referência. Obtidos o diâmetro sagital da imagem do canal cervical e o comprimento da imagem da barra de metal na radiografia, e conhecendo o tamanho real da barra de metal, o diâmetro real do canal medular pôde ser estimado matematicamente com o uso do teorema de Tales. Os resultados obtidos para o DCCC foram comparados com valores encontrados em estudos com cadáveres, foi avaliada a concordância entre DCCC e o diâmetro médio-sagital do canal cervical aferido por ressonância magnética (DCRM) e os métodos radiográficos (DCCC e IT) foram correlacionados com o SAC/SACD. Os cálculos foram realizados nos níveis C3 a C7, além das médias de C3 a C6 [DCCC (MDCCC), IT (MTorg) e SAC/SACD (MSAC/MSACD)]. RESULTADOS: Os valores obtidos pelo DCCC (média do MDCCC: 15.29 mm) foram compatíveis com os valores descritos em estudos de medida direta. A correlação entre DCCC e SAC/SACD foi superior à correlação entre IT e SAC/SACD, sendo de 0.7025 para MDCCC e MSACD contra 0.5473 para MTorg e MSACD. O teste de concordância entre os valores absolutos para DCCC e DCRM evidenciou valores mais elevados na medida por DCCC, sendo média de 1.84 mm maior para MDCCC em relação a média de C3 a C6 pelo DCRM. CONCLUSÕES: O Diâmetro Corrigido do Canal Cervical apresentou valores semelhantes aos encontrados em estudos com medida direta em cadáveres e apresentou correlação com SAC/SACD superior ao IT / INTRODUCTION: Cervical spinal stenosis is the diminution of the anteroposterior diameter of the spinal canal and it is associated with increased risk of neurological injury from cervical trauma. In collision sports, the cervical canal stenosis is an important parameter in the return to play decision after cervical cord neuropraxia and after some brachial plexus injuries. The methods currently available for evaluation of cervical canal stenosis in athletes are expensive (eg, nuclear magnetic resonance) or imprecise (radiographic methods). This study evaluated a new radiographic method for determination of cervical canal stenosis, comparing it to measurements performed on cadavers, measurement by magnetic resonance imaging of the cervical canal and space available for the cord (SAC/SACD) and the consecrated radiographic method for determining cervical spinal stenosis, Torg ratio(TI). METHODS: The study population were 20 men between 16 and 35 years. The subjects underwent a magnetic resonance imaging of the cervical spine to determine the SAC/SACD and cervical radiographs to determine the IT and the proposed new radiographic method, called corrected cervical canal diameter (DCCC). To determine the DCCC, a 100 mm metal bar was used vertically over the cervical midline, using the spinous processes of the cervical vertebrae as reference. Got the radiographic diameter of the medullary canal and the length of the metal bar image on the radiograph , and knowing the actual size of the metal bar , the actual diameter of the spinal canal could be estimated mathematically with the simple use of the theorem of Thales. The results for the DCCC were compared with values found in cadavers studies, the agreement between DCCC and the mid-sagittal diameter of the cervical canal measured by magnetic resonance imaging (DCRM) was calculated and radiographic methods (DCCC and IT) were correlated with SAC/SACD. Calculations were performed individually for C3 to C7 and averages of C3 to C6 [DCCC (MDCCC), IT (MTorg) and SAC/SACD (MSAC/ MSACD)]. RESULTS: The values obtained by DCCC (average MDCCC: 15:29 mm) were consistent with the values described in studies using direct measurement. The correlation between DCCC and SAC/SACD was higher than the correlation between IT and SAC/SACD, being 0.7025 for MDCCC and MSACD and 0.5473 for MTorg and MSACD. The agreement between absolute values for DCCC and DCRM showed higher values for DCCC, which average 1.84 mm greater for MDCCC compared to the average of C3 to C6 for DCRM. CONCLUSIONS: The Fixed Diameter of the Cervical Canal showed similar values to those found in studies with direct measurement from cadavers and correlated with SAC/SACD better than IT
106

Avaliação eletroneurográfica comparativa precoce de pacientes com plexopatia braquial obstétrica / Electroneurography for early prognostic assessment of obstetrical brachial plexopathy

Carlos Otto Heise 01 October 2003 (has links)
O desenvolvimento de um método eficiente de avaliação prognóstica precoce seria de grande utilidade na seleção de lactentes com plexopatia braquial obstétrica para cirurgias de reconstrução do plexo braquial. Realizamos uma eletroneurografia bilateral em 33 bebês com plexopatia braquial obstétrica entre 10 e 60 dias de vida. Foram avaliadas e comparadas lado a lado as amplitudes dos potenciais de ação musculares compostos dos nervos axilar, musculocutâneo, radial proximal, radial distal, mediano e ulnar. Os bebês foram seguidos clinicamente até os seis meses de vida, quando foram submetidos a uma avaliação da força de vários grupos musculares e a uma prova funcional. Uma redução da amplitude do potencial de ação muscular composto em qualquer nervo do membro acometido maior ou igual a 90% da amplitude do potencial do membro sadio correlacionou-se com um resultado clínico ruim aos seis meses de idade (p < 0,01). A acurácia prognóstica da eletroneurografia foi de 91% para as lesões do tronco superior, 97% para as lesões do tronco médio e 100% para as lesões do tronco inferior. Nossos resultados indicam que a eletroneurografia parece ser um instrumento útil na avaliação prognóstica precoce de pacientes com plexopatia braquial obstétrica / Early prognostic assessment of obstetric brachial plexopathies would be a major step for rational selection of infants for brachial plexus surgery. We performed bilateral electroneurography of Axillary, Musculocutaneous, proximal Radial, distal Radial, Median and Ulnar nerves in 33 babies (age 10 - 60 days) with obstetrical brachial plexus lesions in order to compare the amplitude of compound muscle action potentials (CMAPs). The babies were followed up for six months and the outcome was classified according to muscle power score and functional performance. A CMAP amplitude reduction in any nerve of the injured side superior or equal to 90% of CMAP amplitude of the normal side was related to an unfavorable clinical result at age of six months (p < 0,01). The prognostic accuracy of electroneurography was 91% for the upper trunk, 97% for the middle trunk and 100% for the lower trunk. Our results indicate that electroneurography seems to be a useful tool for very early prognostic assessment of obstetric brachial plexopathies
107

Alterações vasculares em pacientes com doença renal crônica com hiperparatiroidismo secundário / Vascular changes in chronic renal disease patients with secondary hyperparathyroidism

Valéria Aparecida da Costa Hong 30 September 2008 (has links)
Fundamentos: Hiperparatiroidismo secundário (HPT2), hiperfosfatemia e produto cálcio x fósforo elevado são associados com doença cardiovascular (DCV) em pacientes com doença renal crônica (DRC). Um papel mais direto exercido pelo PTH neste contexto é controvertido. O objetivo deste estudo foi avaliar como o PTH, cálcio, fósforo e produto cálcio x fósforo interagem para influenciar a função e estrutura vascular de pacientes com DRC com níveis diferentes de PTH e graus diversos de HPT2. Mais especificamente, nós procuramos verificar se o efeito do PTH sobre o sistema vascular ocorre via alterações nos níveis de cálcio e fósforo ou do estresse oxidativo. Métodos: A reatividade vascular das artérias musculares e as características morfofuncionais das artérias de condução foram determinadas em 31 pacientes com DRC tratados por hemodiálise (46 ± 13 anos de idade, 65% do sexo masculino, 48% caucasóides, 52% afro-brasileiros, em tratamento por hemodiálise por 67 meses, PTH 541 ± 389 [mediana 472, intervalo 81 1437], Ca 10,3 ± 1,0, P 6,0 ± 1,5, Ca x P 62 ± 15) e em 22 controles normais. O diâmetro da artéria braquial foi determinado por ultra-sonografia vascular de alta resolução em condições basais, depois de hiperemia reativa (vasodilatação mediada por fluxo, VMF, dependente do endotélio) e após administração de nitrato, um dilatador de ação direta sobre o músculo liso arterial (vasodilatação independente do endotélio, VIE). A rigidez e as características anatômicas das artérias elásticas foram determinadas na carótida e na aorta. Estresse oxidativo, um fator associado à disfunção endotelial, foi avaliado pela dosagem plasmática das espécies reativas ao ácido tiobarbitúrico (TBARS). Resultados: Comparados aos controles tanto a VMF (6,0 ± 4,3% versus 11,3 ± 4,5%) como a vasodilatação independente do endotélio (11,9 ± 7,7% versus 19,1 ± 6,4%) estavam significativamente reduzidas nos pacientes com DRC (p < 0,01). A VMF correlacionou-se negativamente com o PTH (r = - 0,429, p < 0.05) e com a idade (r = -0,365, p = 0,04) e positivamente com a vasodilatação independente do endotélio (r = 0,483, p < 0,01). Na análise multivariada, apenas PTH (p = 0,009) foi o preditor independente de disfunção endotelial. Cálcio, fósforo, produto cálcio x fósforo, albumina, pressão arterial, duração da diálise, hematócrito e lípides não influenciaram a VMF nos pacientes. A distensão da carótida correlacionou-se negativamente e independentemente de outros fatores com o produto cálcio x fósforo (r = - 0,565, p = 0,003) e com a idade (r = - 0,627, p = 0,003), mas não foi influenciada pelo PTH. A velocidade de onda de pulso correlacionou-se apenas com a idade (r = 0,544, p = 0,003). O estresse oxidativo foi mais elevado nos pacientes que nos controles (2,63 ± 0,51 nmoles/mL versus 1,49 ± 0,43 nmoles/mL, p < 0,001). Entre os pacientes o estresse oxidativo não se correlacionou com a reatividade vascular ou com as variáveis das artérias de condução. No entanto, no conjunto formado por pacientes e controles observamos uma correlação negativa do TBARS com a VMF (r = -0,56, p < 0,001) e positiva com a pressão arterial sistólica (r = 0,48, p < 0,001). Conclusão: Na DRC, o PTH tem efeito adverso sobre a reatividade vascular, possivelmente interferindo com a função endotelial, enquanto que a distensão das grandes artérias elásticas é influenciada negativamente pelo produto cálcio x fósforo e idade, porém não pelo PTH. Os resultados sugerem a existência de um mecanismo duplo de agressão vascular no HPT2: um efeito endotelial mediado pelo PTH e um efeito média/adventicial ligado a alterações do metabolismo mineral / Background: Secondary hyperparathyroidism (2HPT), hyperphosphataemia and a high calcium x phosphorus product are associated with cardiovascular disease (CVD) in patients with chronic kidney disease (CKD). A more direct role played by parathormone (PTH) in this context is controversial. The purpose of this study was to evaluate how PTH, calcium, phosphorus and calcium x phosphorus product interact to influence vascular structure and function of patients with different levels of PTH and varying degrees of 2HPT. Specifically, our purpose was verify whether calcium, phosphorus and oxidative stress are involved on the effects of PTH on the vascular system. Methods: Vascular reactivity of the muscular arteries and the morpho-functional characteristics of condutance vessels were determined in 31 patients with CKD treated by hemodialysis (46 ± 13 years of age, 65% males, 48% Caucasians, 52% African- Brazilians, in haemodialysis treatment for 67 months, PTH 541 ± 389 [median 472, range 81 - 1437], Ca 10.3 ± 1.0, P 6.0 ± 1.5, Ca x P 62 ± 15) and in 22 normal controls. The diameter of the brachial artery was determined by vascular high-resolution ultrasound on baseline, after reactive hyperemia (flow-mediated vasodilation, FMD, dependent of the endothelium) and after administration of nitrate, a dilator of direct action on the smooth muscle blood (vasodilation independent of the endothelium, VIE). The stiffness and the anatomical features of elastic arteries were determined in the carotid artery and aorta. Oxidative stress, a factor associated with endothelial dysfunction, was evaluated by the level of plasma thiobarbituric acid-reactive species (TBARS). Results: Compared to the controls, both the FMD (6.0 ± 4.3% versus 11.3 ± 4.5%) as well as VIE (11.9 ± 7.7% versus 19.1 ± 6.4 %) were significantly reduced in patients with CKD (p <0.01). The FMD was negatively correlated with PTH (r = - 0429, p <0.05) and with age (r = -0365, p = 0.04) and positively with the endothelium-independent vasodilation (r = 0483, p < 0.01). In the multivariate analysis, only PTH (p = 0009) was an independent predictor of endothelial dysfunction. Calcium, phosphorus, calcium x phosphorus product, alkaline phosphatase, albumin, blood pressure, duration of dialysis, hematocrit and lipids did not influence the FMD. The distension of the carotid artery was negatively correlated the calcium x phosphorus product (r = - 0565, p = 0003) and with age (r = - 0627, p = 0003), but was not influenced by PTH . Pulse wave velocity correlated only with age (r = 0544, p = 0003). Oxidative stress was higher in patients than in controls (2.63 ± 0.51, nmoles/ml versus 1.49 ± 0.43 nmoles/ml, p <0001) and correlated with FMD (r = - 0,56, p< 0,001) and systolic blood pressure (r = 0,48, p < 0,001) in the totality of individuals (patients and controls). Conclusion: In CKD, PTH adversely affects vascular reactivity, possibly by interfering with endothelial function, while large vessel distension is influenced by the calcium x phosphorus product and age, but not by PTH. This result suggests a dual mechanism of vascular aggression in vascular 2HPT: an endothelial effect mediated by PTH and a media/adventitial effect linked to alterations of mineral metabolism
108

Biceps brachii synergy and its contribution to target reaching tasks within a virtual cube

He, Liang 07 1900 (has links)
Ces dernières années, des travaux importants ont été observés dans le développement du contrôle prothétique afin d'aider les personnes amputées du membre supérieur à améliorer leur qualité de vie au quotidien. Certaines prothèses myoélectriques modernes des membres supérieurs disponibles dans le commerce ont de nombreux degrés de liberté et nécessitent de nombreux signaux de contrôle pour réaliser plusieurs tâches fréquemment utilisées dans la vie quotidienne. Pour obtenir plusieurs signaux de contrôle, de nombreux muscles sont requis mais pour les personnes ayant subi une amputation du membre supérieur, le nombre de muscles disponibles est plus ou moins réduit selon le niveau de l’amputation. Pour accroître le nombre de signaux de contrôle, nous nous sommes intéressés au biceps brachial, vu qu’anatomiquement il est formé de 2 chefs et que de la présence de compartiments a été observée sur sa face interne. Physiologiquement, il a été trouvé que les unités motrices du biceps sont activées à différents endroits du muscle lors de la production de diverses tâches fonctionnelles. De plus, il semblerait que le système nerveux central puisse se servir de la synergie musculaire pour arriver à facilement produire plusieurs mouvements. Dans un premier temps on a donc identifié que la synergie musculaire était présente chez le biceps de sujets normaux et on a montré que les caractéristiques de cette synergie permettaient d’identifier la posture statique de la main lorsque les signaux du biceps avaient été enregistrés. Dans un deuxième temps, on a réussi à démontrer qu’il était possible, dans un cube présenté sur écran, à contrôler la position d’une sphère en vue d’atteindre diverses cibles en utilisant la synergie musculaire du biceps. Les techniques de classification utilisées pourraient servir à faciliter le contrôle des prothèses myoélectriques. / In recent years, important work has been done in the development of prosthetic control to help upper limb amputees improve their quality of life on a daily basis. Some modern commercially available upper limb myoelectric prostheses have many degrees of freedom and require many control signals to perform several tasks commonly used in everyday life. To obtain several control signals, many muscles are required, but for people with upper limb amputation, the number of muscles available is more or less reduced, depending on the level of amputation. To increase the number of control signals, we were interested in the biceps brachii, since it is anatomically composed of 2 heads and the presence of compartments was observed on its internal face. Physiologically, it has been found that the motor units of the biceps are activated at different places of the muscle during production of various functional tasks. In addition, it appears that the central nervous system can use muscle synergy to easily produce multiple movements. In this research, muscle synergy was first identified to be present in the biceps of normal subjects, and it was shown that the characteristics of this synergy allowed the identification of static posture of the hand when the biceps signals had been recorded. In a second investigation, we demonstrated that it was possible in a virtual cube presented on a screen to control online the position of a sphere to reach various targets by using muscle synergy of the biceps. Classification techniques have been used to improve the classification of muscular synergy features, and these classification techniques can be integrated with control algorithm that produces dynamic movement of myoelectric prostheses to facilitate the training of prosthetic control.
109

Peripheral Arterial Disease as an Independent Predictor for Excess Stroke Morbidity and Mortality in Primary-Care Patients: 5-Year Results of the getABI Study

Meves, Saskia H., Diehm, Curt, Berger, Klaus, Pittrow, David, Trampisch, Hans-Joachim, Burghaus, Ina, Tepohl, Gerhart, Allenberg, Jens-Rainer, Endres, Heinz G., Schwertfeger, Markus, Darius, Harald, Haberl, Roman L. January 2010 (has links)
Background:There is controversial evidence with regard to the significance of peripheral arterial disease (PAD) as an indicator for future stroke risk. We aimed to quantify the risk increase for mortality and morbidity associated with PAD. Methods:In an open, prospective, noninterventional cohort study in the primary care setting, a total of 6,880 unselected patients ≧65 years were categorized according to the presence or absence of PAD and followed up for vascular events or deaths over 5 years. PAD was defined as ankle-brachial index (ABI) <0.9 or history of previous peripheral revascularization and/or limb amputation and/or intermittent claudication. Associations between known cardiovascular risk factors including PAD and cerebrovascular mortality/events were analyzed in a multivariate Cox regression model. Results:During the 5-year follow-up [29,915 patient-years (PY)], 183 patients had a stroke (incidence per 1,000 PY: 6.1 cases). In patients with PAD (n = 1,429) compared to those without PAD (n = 5,392), the incidence of all stroke types standardized per 1,000 PY, with the exception of hemorrhagic stroke, was about doubled (for fatal stroke tripled). The corresponding adjusted hazard ratios were 1.6 (95% confidence interval, CI, 1.1–2.2) for total stroke, 1.7 (95% CI 1.2–2.5) for ischemic stroke, 0.7 (95% CI 0.2–2.2) for hemorrhagic stroke, 2.5 (95% CI 1.2–5.2) for fatal stroke and 1.4 (95% CI 0.9–2.1) for nonfatal stroke. Lower ABI categories were associated with higher stroke rates. Besides high age, previous stroke and diabetes mellitus, PAD was a significant independent predictor for ischemic stroke. Conclusions:The risk of stroke is substantially increased in PAD patients, and PAD is a strong independent predictor for stroke. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
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Associação dos achados morfofuncionais cardíacos, renais e vasculares com as alterações do índice tornozelo-braço em pacientes hipertensos diabéticos / Association of cardiac, renal and vascular morphological and functional findings with changes in ankle brachial index in diabetic hypertensive patients

Pompeu Filho, José Carlos Jucá 12 August 2015 (has links)
Introdução: Inúmeros estudos estabeleceram correlações entre o índice tornozelo-braço (ITB), um marcador de aterosclerose subclínica, e o prognóstico cardiovascular em diferentes populações. No entanto, poucos estudos avaliaram a correlação entre os valores do ITB e lesões cardiovasculares e renais, exclusivamente, em pacientes com hipertensão arterial e diabetes. Objetivo: Estudar a prevalência de alterações morfofuncionais cardíacas, carotídeas, retinianas e renais de acordo com a presença ou não de valores de ITB alterados (ITB <= 0,9 ou ITB > 1,4) em pacientes hipertensos com diabetes tipo 2. Métodos: Foram incluídos no estudo 99 pacientes hipertensos diabéticos com idade entre 50 e 80 anos. A aferição do ITB foi realizada em todos os pacientes por método validado e estes foram classificados em Grupo 1 (ITB normal, n = 49) ou Grupo 2 (ITB alterado, n =50). Todos os pacientes foram submetidos, em até 06 meses, à realização de ecodopplercardiograma, ultrassonografia de carótidas, retinografia colorida, aferição da taxa de filtração glomerular (TFG) e da albuminúria de 24h. Os pacientes foram analisados para a ocorrência ou não de um desfecho-composto ecocardiográfico que incluiu alterações morfológicas e funcionais cardíacas relevantes para a prática clínica. Os pacientes dos grupos 1 e 2 foram também comparados quanto à prevalência de placas carotídeas com ou sem repercussão hemodinâmica, TFG < 60 ml/mim/m2, albuminúria de 24h > 30mg e presença ou não de retinopatia. Por fim, foram comparadas as frequências médias das seguintes lesões de órgãos-alvo de ambos os grupos, considerando-se valor unitário para a presença de cada uma delas: hipertrofia do ventrículo esquerdo, retinopatia hipertensiva, TFG < 60 ml/min/m2 e estenose da artéria carótida interna > 50% do seu diâmetro. Resultados: A média de idade dos pacientes foi 65,4 ± 7 anos, sendo 61,6% deles do sexo feminino. A presença de níveis elevados de pressão arterial sistólica (153,4 ± 18 versus 170 ± 26 mmHg), de albuminúria de 24h > 30mg (55,3% versus 82,6%) e de TFG < 60 ml/min/m2 (12,8% versus 33,3%) foi significativamente maior (p < 0.05) entre os pacientes do Grupo 2. O desfecho-composto ecocardiográfico foi mais prevalente no grupo 2 (84,0% versus 59,2%; p = 0,006) e a frequência média de lesões de órgãos-alvo também foi maior nos pacientes do grupo 2 (0,36 ± 0,31 versus 0,19 ± 0,19; p = 0,001). Análise por regressão logística binária revelou que o ITB foi uma das variáveis preditoras independentes para o desfecho-composto ecocardiográfico (OR = 3,43; IC 95% = 1,07 - 11,0; p = 0,04). A partir da análise por regressão linear obteve-se um modelo final no qual o ITB foi uma das três variáveis preditoras independentes para a estimativa da frequência média de lesões de órgãos-alvo com coeficiente beta = 13,22 (1,81 - 24,63), ao lado da idade e do infarto prévio. Conclusão: Nossos dados mostram que valores de ITB alterados estão associados à maior prevalência de lesões em órgãos-alvo, principalmente alterações ecocardiográficas, em pacientes com hipertensão arterial e diabetes / Introduction: A lot of studies have established strong correlations between the ankle-brachial index (ABI), a marker of subclinical atherosclerosis and cardiovascular prognosis in different populations. However, few studies have assessed the correlation between the values of the ABI and cardiovascular and renal lesions in patients with hypertension and diabetes. Objective: To study the prevalence of cardiac, carotid, renal and retinal morphological and functional changes according to the presence or not of altered ABI values (ABI <= 0.9 or ABI > 1.4) in hypertensive patients with type 2 diabetes. Methods: It was included 99 diabetic hypertensive patients aged between 50 and 80 years. The measurement of the ABI was performed in all patients by validated method and they were classified in Group 1 (normal ABI, n = 49) or group 2 (altered ABI, n = 50). All patients were submitted, up to 6 months, to Doppler echocardiography, carotid ultrasound, color retinography, assessment of glomerular filtration rate (GFR) and 24h albuminuria. Patients were analyzed for the occurrence or not of a composite echocardiographic outcome which included morphological and functional cardiac alterations relevant to clinical practice. Patients in groups 1 and 2 were compared regarding the prevalence of carotid plaques with or without hemodynamic repercussion, TFG < 60 ml/min/m2, 24h albuminuria > 30 mg and the presence or not of retinopathy. Finally, we compared the prevalence of mean frequency of the following end-organ lesions of both groups, considering unit value for each one: left ventricular hypertrophy, hypertensive retinopathy, TFG < 60 ml/min/m2 and internal carotid artery stenosis > 50%. Results: The mean age of the patients was 65.4 ± 7 years, with 61.6% of them female. The presences of elevated levels of systolic blood pressure (153.4 ± 18 versus 170.0 ± 26 mmHg), of 24h albuminuria > 30 mg (55.3% versus 82.6%) and TFG < 60 ml/min/m2 (12.8% vs. 33.3%) were significantly greater (p < 0.05) among the patients of Group 2. The composite echocardiographic outcome was more prevalent in Group 2 (84.0% versus 59.2%, p = 0.006) and the average frequency of subclinical injury of target organs was also greater in patients of Group 2 (0.36 ± 0.31 versus 0.19 ± 0.19; p = 0.001). Binary logistic regression analysis revealed that the ABI was one of the independent predictors of composite echocardiographic outcome (OR = 3.43; IC 95% = 1.07 - 11.0; p = 0.04). From the linear regression analysis it was obtained a final model in which the ABI was one of three independent predictors for the estimation of the average frequency of end-organ damage with ? coefficient = 13.22 (1.81-24.63), besides age and previous myocardial infarction. Conclusion: Our data demonstrates that changed ABI values are associated with higher prevalence of subclinical end-organ lesions, principally changes in echocardiographic parameters, in patients with hypertension and diabetes

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