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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.
91

Escore de cálcio coronariano, índice tornozelobraquial e proteína C reativa em tabagistas pesados com doença pulmonar obstrutiva crônica e com espirometria normal

Ferreira, Maria Angelica Pires January 2014 (has links)
INTRODUÇÃO. Estudos de qualidade variável mostram maior prevalência de doença cardiovascular e de marcadores de aterosclerose em tabagistas com doença pulmonar obstrutiva crônica (DPOC) em relação a tabagistas sem a doença. OBJETIVOS. Verificar se escore de cálcio coronariano (ECC) elevado e anormalidade do índice tornozelo-braquial (ITB) são mais prevalentes em tabagistas pesados com DPOC do que sem DPOC, e se proteína C reativa sérica (PCR) e volume expiratório forçado no primeiro segundo em relação ao previsto (VEF1%) se correlacionam com ECC e ITB em tabagistas com e sem DPOC. POPULAÇÃO E MÉTODOS. Foram incluídos indivíduos consecutivos com carga tabágica @ 20 maços-ano. Os pacientes foram divididos em grupo 1 (com DPOC) e grupo 2 (assintomáticos respiratorios com espirometria normal). Coletaram-se dados clínicos, laboratoriais e antropométricos e determinados ECC, ITB e PCR sérica. Comparouse a prevalência de ECC acima do percentil 75 e de ITB anormal entre os grupos, e verificou-se a correlação entre PCR, ECC e ITB e entre VEF1%, ECC e ITB. / BACKGROUND. Studies of various quality levels show higher prevalence of cardiovascular disease and atherosclerosis markers in smokers with chronic obstructive pulmonary disease (COPD) compared to smokers without the disease. OBJECTIVES. The aims of this study were, firstly, to verify whether an elevated coronary calcium score (CCS) and abnormal ankle-brachial index (ABI) are more prevalent in heavy smokers with COPD than in those without COPD, and secondly, to investigate whether serum C-reactive protein (CRP) and predicted forced expiratory volume in the first second (FEV1%) are correlated with CCS and ABI in smokers with and without COPD. METHODS. We included clinically stable consecutive individuals with smoking history of @ 20 pack-years and COPD (group 1) or normal spirometry (group 2). Clinical, laboratory and anthropometric data were collected and CCS, ABI and serum CRP were measured. We compared the prevalence of CCS above the 75th percentile and the rates of abnormal ABI in both groups. Additionally, the correlation between CRP, CCS and ABI and FEV1%, CCS, and ABI was determined.
92

Avaliação da medida do índice tornozelo-braquial em portadores de hipercolesterolemia familiar / Assessment ot the ankle-brachial index in patients with familial hypercholesterolemia

Carolina Pereira 20 February 2014 (has links)
A hipercolesterolemia familiar (HF) é uma doença de herança genética autossômica dominante caracterizada pela elevação dos níveis séricos de colesterol total e das lipoproteínas de baixa densidade (LDL- c). Conhecida por estar estreitamente relacionada ao processo aterosclerótico, a HF pode determinar o desenvolvimento de lesões obstrutivas precoces em distintos leitos arteriais. Nesse contexto, a HF também tem sido proposta como um fator de risco para a doença arterial periférica (DAP). Avaliamos assim de forma sistemática por meio de um estudo transversal e observacional, a prevalência de DAP em uma população brasileira de portadores de HF. Estudamos também sua associação com diversos fatores de risco cardiovascular, incluindo sexo, idade, hipertensão arterial sistêmica, diabetes mellitus, tabagismo, perfil lipídico, níveis séricos de glicemia e creatinina. Avaliou-se também a associação da DAP com histórico prévio de doença cardiovascular (DCV) bem como sua associação com marcadores de aterosclerose subclínica representados pela angiotomografia coronariana e escore de cálcio coronário. Foram estudados 212 portadores de HF, sendo que em 86% foi comprovada presença de mutação do receptor da LDL e um grupo de comparação composto por 524 indivíduos normolipidêmicos. O rastreamento da DAP foi realizado por dois avaliadores treinados, pela medida do índice tornozelo-braquial (ITB) avaliado em repouso na posição supina, com Doppler vascular portátil. Houve maior prevalência de DAP definida por ITB <= 0,90 em portadores de HF comparados aos controles (17,5% vs. 2,3%, respectivamente; p < 0,001). As variáveis que se associaram independentemente com a alteração dos valores do ITB nos grupos estudados foram, a idade, antecedente prévio de doença cardiovascular e o indivíduo ser portador de HF (OR= 5,77 IC 95% 2,83-11,77, p < 0,001). Na população de HF as variáveis que se associaram independentemente à alteração dos valores de ITB foram a idade e a presença de histórico de tabagismo ativo ou passado. Houve uma associação univariada entre o histórico de doença cardiovascular e o diagnóstico de doença arterial periférica nesta população (OR= 3,20 IC 95% 1,53-6,67, p=0,001), porém tal associação não se manteve significativa quando ajustada por variáveis de confusão. Da mesma forma não se encontrou associação entre os valores alterados de ITB e a presença de placa coronariana e sua gravidade, bem como com o escore de cálcio coronário. Os dados sugerem dissociação entre o desenvolvimento da aterosclerose em diferentes leitos arteriais .Em conclusão, nossos resultados indicam que a DAP é mais frequente na HF do que em indivíduos normolipidêmicos e que outros fatores de risco potencializam o colesterol para sua presença. Não foi encontrada associação independente da alteração do ITB com manifestação de DCV prévia e com a aterosclerose coronária subclínica. Contudo, mais estudos são necessários para determinar o papel do uso do ITB como ferramenta para avaliação do risco de eventos cardiovasculares nessa população / Familial hypercholesterolemia (FH) is a genetic disease of autosomal dominant inheritance characterized by elevated serum levels of total and low density lipoprotein ( LDL - c ) cholesterol. FH is associated to atherosclerosis and can determine the early development of obstructive lesions in different arterial beds. In this context, FH has also been proposed as a risk factor for peripheral arterial disease (PAD). In a cross-sectional observational study the prevalence of PAD in a Brazilian population of patients with FH was determined . We also study its association with several cardiovascular risk factors, including gender, age , hypertension , diabetes mellitus , smoking , lipid profile , serum glucose and creatinine. The association of PAD with previous manifestations of cardiovascular disease (CVD) and with markers of subclinical coronary atherosclerosis detected by computed tomography coronary angiography and coronary calcium score was also evaluated. We studied 212 patients with FH, of which 86% had a confirmed diagnosis by the presence of LDL receptor mutations, and a comparison group consisting of 524 normolipidemic subjects . PAD diagnosis was made by 2 trained evaluators, by the ankle-brachial index ( ABI ) measured at rest in the supine position. There was a higher prevalence of PAD defined as ABI <= 0.90 in patients with HF compared with controls (17.5 % vs . 2.3% , p < 0.001 ) . The variables that were independently associated with altered ABI values in both groups were age, previous history of CVD and the diagnosis of FH (OR = 5.77 95% CI 2.83 to 11.77 , p < 0.001). In FH subjects variables independently associated with altered ABI values were age and the presence of current or past smoking history. There was a univariate association between CVD history and the diagnosis of PAD in this population (OR = 3.20 95% CI 1.53 to 6.67 , p = 0.001), but this association did not remain significant when adjusted for confounders . Likewise, no association was found between the values of altered ABI and the presence of coronary plaque and its severity, as well with the coronary calcium score. The data suggest that there is a dissociation of atherosclerosis development in different arterial beds. In conclusion, our results indicate that PAD is more common in FH than in normolipidemic subjects and that other risk factors potentiate cholesterol to determine its presence. No independent association was found between the alteration of ABI values with manifestations of prior CVD, as well as with the presence of subclinical coronary atherosclerosis. More studies are needed to determine the role of ABI use as a tool for assessing the risk of cardiovascular events in FH
93

Variação do índice tornozelo-braquial pré e pós-hemodiálise: correlação com água corporal, cálcio do dialisato e sistema nervoso autônomo / Variation of the ankle-brachial index before and after hemodialysis: correlation with body water, dialysate calcium and autonomic nervous system

Zaida Noemy Cabrera Jimenez 24 November 2016 (has links)
Introdução: O índice de pressão tornozelo-braquial (ITB) é definido como a relação da maior pressão arterial sistólica nos membros inferiores sobre a maior pressão arterial sistólica nos membros superiores. O ITB, quando alterado, seja baixo ou alto, é capaz de marcar pacientes em hemodiálise (HD) com maior risco de mortalidade. Porém, alterações agudas deste índice na HD são pouco estudadas. Acreditamos que uma maior variabilidade do ITB possa refletir alterações funcionais dos vasos ou do sistema nervoso autônomo. Uma maior concentração de cálcio no dialisato, poderia levar a um maior estímulo simpático e influenciar o comportamento das variações agudas do ITB. O objetivo central do presente estudo foi analisar o comportamento do ITB pré vs. pós-diálise, tanto de forma absoluta quanto categórica (aumentar vs. baixar), em uma população de pacientes incidentes em HD, comparando uso de dialisato com concentrações de cálcio (Ca) 3,5 e 2,5 mEq/l. Métodos: Este foi um estudo prospectivo em que os pacientes foram estudados na HD do meio da semana, em duas semanas consecutivas, com banho na concentração de Ca de 3,5 e 2,5 mEq/l. Dados clínicos, demográficos, bioquímicos, além do ITB pré e pós HD, análise de fluidos corporais (por bioimpedância) e análise do sistema nervoso autônomo através de variabilidade de frequência cardíaca (obtida com Finometer®) foram obtidos. Resultados: Foram estudados 30 pacientes, com idade média de 47 ± 16 anos hipertensos na totalidade, 10% diabéticos. Anemia, hipocalcemia e altos níveis de fração N-terminal de peptídeo natriurético cerebral foram observados. A maior parte dos pacientes apresentaram pré diálise um ITB normal (entre 0,9 e 1,3), enquanto ITB alto ( > 1,3) foi encontrado em 16,7 a 23,3% e ITB baixo ( < 0,9) em 3,3 a 13,4% dos casos, dependendo da fase do estudo (Ca 3,5 ou 2,5 mEq/l). Não houve diferença na média do ITB pré vs. pós HD tanto com Ca 3,5 quanto com Ca 2,5 mEq/l (p=0,888 e p=0,712, respectivamente). Não encontramos diferença entre o número de pacientes que aumentou e diminuiu o ITB com as duas concentrações de Ca (p=0,889). Um aumento da relação baixa frequência/alta frequência, que indica maior estímulo simpático, foi mais frequente com o uso de Ca 3,5 mEq/l (p=0,026). Pacientes que aumentaram esta relação tiveram 4,5 vezes maior risco de apresentarem queda do ITB (p=0,031) com o Ca 3,5 mEq/l. A avaliação vascular através da velocidade de onda de pulso não se correlacionou com variações intra-dialíticas do ITB. Conclusão: Apesar de concentrações maiores de Ca no dialisato estarem associadas a uma melhor estabilidade hemodinâmica durante a HD, isto possivelmente ocorre em decorrência da hiperatividade simpática, que pode levar a consequências deletérias a longo prazo. A atividade simpática com o uso de Ca 3,5 mEq/l se associou com queda do ITB de pré para pós HD. Se este comportamento agudo do ITB pode trazer consequências a longo prazo ainda não sabemos e novos estudos serão necessários / Introduction: The ankle-brachial index (ABI) is defined as the ratio of the higher systolic blood pressure in the lower limbs and the higher systolic blood pressure in the upper limbs. Both low and high ABI can predict mortality among patients on hemodialysis (HD). However, little is known about acute changes in this index during HD. We believe that greater variability of ABI may reflect functional changes of vessels or changes in the autonomic nervous system. A higher dialysate calcium concentration could lead to an increase of sympathetic activity and influence the behaviour of acute variations of the ABI. The aim of this study was to analyze the ABI pre- vs. post-dialysis, both as continuous and categorized (increased vs. decreased) variable, in a population of incident hemodialysis patients, comparing the use of dialysate calcium (Ca) concentration of 3.5 and 2.5 mEq/L. Methods: this was a prospective study, in which patients were studied in the midweek HD session, in two consecutive weeks, with Ca 3.5 and 2.5 mEq/l. Clinical, demographic, biochemical, and also pre and post HD ITB, fluid volume analysis (by bioimpedance) and analysis of the autonomic nervous system (by heart rate variability obtained with Finometer®) were evaluated. Results: 30 patients were studied, mean age 47 ± 16 years, all hypertensive, and 10% diabetics. Anemia, hypocalcemia and high levels of N-terminal brain natriuretic peptide were observed. Most patients had a normal pre dialysis ABI (0.9 to 1.3), while ABI high ( > 1.3) was found in 16.7 to 23.3% and low (<0.9) in 3.3 to 13.4% of cases, depending on the study phase (Ca 3.5 or 2.5 mEq/l). There was no difference in ABI average pre vs. post HD with Ca 3.5 and Ca 2.5 mEq/L (p = 0.888 and p = 0.712, respectively). We found no difference between the percentage of patients in which ABI has increased or decreased (p = 0.889). An increase in the ratio low frequency/high frequency, indicating a higher sympathetic stimulation, was more frequent with the use of Ca 3.5 mEq/l (p = 0.026). Patients that have increased this ratio had 4.5 times higher risk of presenting fall in ABI during HD with the Ca 3.5 mEq/l (p = 0.031). The vascular assessment by pulse wave velocity had no correlation with intra-dialysis variations of ABI. Conclusion: Although higher concentrations of Ca in the dialysate are associated with better hemodynamic stability during HD, this happens possibly due to the sympathetic hyperactivity, which can have deleterious long-term consequences. Sympathetic activity with the use of Ca 3.5 mEq/l seems to be associated with fall of the ITB during HD. If this acute behaviour of ABI can lead to long-term consequences is still unknown and deserve further studies
94

"Função endotelial em adultos jovens com infarto do miocárdio. Influências ambientais e genéticas" / Endothelium function in young adults with myocardial infarction

Marcelo Ferraz Sampaio 21 November 2005 (has links)
A disfunção endotelial atua tanto na aterogênese como na precipitação das síndromes coronárias agudas. A redução da biodisponibilidadedo óxido nítrico é expressão de endotélio disfuncional. O mecanismo desta redução não está elucidado. A presença de disfunção endotelialfoi correlacionada com fatores de risco (FR), nitrato sanguíneo e fatores genéticos (polimorfismo da óxido nítrico sintase endotelial, fibrinogênio e PAI-1) em um grupo de 128 pacientes com infarto do miocárdio (IAM) e idade = 40 anos, submetidos a ultra-som de artéria braquial. Os resultados foram comparados com um grupo jovens saudáveis. Verificou-se que pacientes jovens com IAM apresentavam disfunção endotelial em associação com FR, alterações bioquímicas e níveis aumentados de nitrato, porém sem alterações genéticas / The endothelial dysfunction plays an important roll in the atherogenesis and precipitation of acute coronary syndromes. The reduction of bioavailability of the nitric oxide is the expression of endothelial dysfunction. The exact mechanism of this reduction is not yet well explained. In order to evaluate the presence of endothelial dysfunction and correlation with risk factors (FR), nitrate blood levels and genetic factors (endothelial nitric oxide synthease polymorphism, fibrinogen and PAI-1) a 128 myocardial infarction patients group with age = 40 year was studied, and underwent a brachial artery ultra-sound. The results were compared with a group of young health individuals. The study found that the young patients with myocardial infarctions showed endothelial dysfunction with associated risks factors, biochemical changes and higher levels of nitrate, although without any significant genetic changes
95

Uso do índice tornozelo-braquial como preditor de eventos cardiovasculares no pós-operatório de cirurgias não cardíacas / Ankle-brachial index estimating cardiac complications after general surgery

Gabriel Assis Lopes do Carmo 25 April 2014 (has links)
A avaliação perioperatória é uma etapa importante antes de encaminhar o paciente para a realização de uma operação. Algoritmos e escores podem ajudar durante este processo de estratificação de risco e na tomada de decisões. Entretanto, a maior parte deles foram descritos e desenvolvidos em um contexto diferente que pode não representar a realidade médico atual. O índice tornozelo-braquial (ITB) é capaz de quantificar o risco cardiovascular na população em geral. É um método barato e passível de ser realizado ambulatorialmente e poderia ser útil antes da realização de procedimentos cirúrgicos. O trabalho atual é um estudo observacional e prospectivo que avaliou pacientes de risco cardiovascular perioperatório intermediário a alto antes de serem submetidos a cirurgias não cardíacas. O ITB foi aferido em todos os pacientes. Um valor <=0,9 foi considerado alterado, definindo o grupo portador de doença arterial periférica. Os demais pacientes constituíram o grupo controle. Traçados eletrocardiográficos e dosagem sérica de troponina foram obtidos em todos os pacientes nas primeiras 72 horas após o procedimento. Todos os pacientes foram seguidos por um período de 30 dias, sendo o desfecho primário um combinado de eventos cardiovasculares (mortalidade cardiovascular, síndrome coronariana aguda, elevação isolada de troponina, insuficiência cardíaca descompensada, choque cardiogênico, arritmias instáveis, parada cardíaca não fatal, edema agudo de pulmão, acidente vascular cerebral e doença arterial periférica descompensada). Foram avaliados 132 pacientes (61,3% do sexo masculino; idade média 65,4 anos). Durante o período de acompanhamento especificado 57,9% dos pacientes com ITB <= 0,9 apresentaram o desfecho primário vs 25,7% no grupo controle (p=0,011). Após análise multivariada por regressão logística, o odds ratio (OR) para a ocorrência desta complicação foi de 7,4 (IC 95% 2,2-25,0, p=0,001) e o valor de P para o teste de Hosmer-Lemeshow foi de 0,626. A elevação isolada de troponina foi o principal evento encontrado (78,9%). Análise de desfecho secundário mostrou um OR de 13,4 para a ocorrência de elevação isolada de troponina após regressão logística (IC 95% 3,0-59,9, p=0,001) com o valor de P do teste de Hosmer-Lemeshow de 0,922. Concluímos então que, no período perioperatório, a presença de ITB anormal está associado a pior prognóstico cardiovascular, principalmente devido à elevação isolada de troponina / Perioperative evaluation is an important step before referring a patient to surgery. Scores and algorithms can help during this process. However, most of them were developed in different context that may not represent the actual medical scenario. The ankle-brachial index (ABI) can quantify cardiovascular risk in general population. It is inexpensive and easy to perform in office care and could be useful before surgery. This is a prospective and observational study that evaluated intermediate to high cardiovascular risk patients referred for general surgery. ABI were performed in all patients before surgery. A value <= 0.9 was considered abnormal and defined the peripheral artery disease group, and the remaining patients constituted the control group. Troponin-I and electrocardiogram were provided in the first 72 hours. All patients were followed for 30 days and primary endpoint was a composite of cardiovascular events (cardiovascular mortality, acute coronary syndrome, isolated troponin elevation, decompensated heart failure, cardiogenic shock, unstable arrhythmias, non fatal cardiac arrest, pulmonary edema, stroke and peripheral artery disease decompensation). We evaluated 132 patients (61.3% male; mean age 65.4 years). During the specified period 57.9% of patients with ABI <= 0.9 had a cardiovascular event vs 25.7% in the control group (p=0.011). After logistic regression, the odds ratio (OR) was 7.4 (CI 95% 2.2-25.0, p=0.001) and Hosmer-Lemeshow P=0.626. Isolated troponin elevation was the main event (78.9%). Secondary analysis revealed an OR of 13.4 for the occurrence of secondary endpoint after logistic regression (CI 95% 3.0-59.9, p=0.001) and Hosmer-Lemeshow P = 0.922. In conclusion, in the perioperative setting, an abnormal ankle-brachial index is associated with a worse cardiovascular prognosis, especially due to isolated troponin elevation
96

The value of noncoronary atherosclerosis for identifying coronary artery disease: Results of the Leipzig LIFE Heart Study

Weissgerber, Alexander 26 July 2018 (has links)
No description available.
97

Familiární hyperlipoproteinémie a další rizikové faktory kardiovaskulárních onemocnění u mužů s erektilní dysfunkcí / Familiar hyperlipoproteinemias and other risk factors of cardiovascular diseases in men with erectile dysfunction

Prusíková, Martina January 2012 (has links)
Background: The relationship between erectile dysfunction and risk factors of atherosclerosis has been confirmed by a number of previous investigations. There are also plausible pathophysiological mechanisms explaining the observed association. One of the tested hypotheses in our work was the assumption that risk factors of atherosclerosis would be more prevalent in men with erectile dysfunction than in controls selected from the representative sample of the Czech population. Our work did not confirm this hypothesis. Most likely explanation can be greater representation of younger-middle aged men in our group than in the Czech post-Monica study in which the age distribution was equal. On the other hand authors of the Czech post-Monica study admit worse compliance in younger participants of their survey. Nevertheless, the risk factors of atherosclerosis occur very frequently in males with erectile dysfunction. Results: In our group mean cardiovascular risk calculated according to the SCORE chart was 3.39% (±3,39). In the Czech post-MONICA study conducted between 2007 and 2008 the mean SCORE risk reached 2.47%. There was a trend, though not statistically significant, towards direct relationship between the severity of ED and the SCORE CVD risk. Asymptomatic atherosclerosis was detected in 56.25% of our study...
98

Caractérisation pharmacocinétique et pharmacodynamique de la lidocaïne avec ou sans adrénaline lors d’un bloc paravertébral du plexus brachial chez le chien

Choquette, Amélie 04 1900 (has links)
Au cours des vingt dernières années, l’anesthésie régionale est devenue, autant en médecine vétérinaire qu’humaine, un outil essentiel à l’élaboration de protocoles analgésiques péri-opératoires. Parmi l’éventail de techniques mises au point en anesthésie canine, le bloc paravertébral du plexus vertébral (PBPB) et sa version modifiée sont d’un grand intérêt pour toute procédure du membre thoracique, dans sa portion proximale. Toutefois, l’essentiel des données publiées à ce jour provient d’études colorimétriques, sans évaluation clinique, et peu d’information est disponible sur les techniques de localisation nerveuse envisageables à ce site. Notre étude visait à décrire une approche échoguidée du PBPB modifié, puis à caractériser ses paramètres pharmacocinétiques et pharmacodynamiques après administration de lidocaïne (LI) ou lidocaïne adrénalinée (LA). Huit chiens ont été inclus dans un protocole prospectif, randomisé, en aveugle et croisé, réparti sur trois périodes. L’impact pharmacodynamique du bloc effectué avec LI ou LA a été évalué régulièrement pour 180 min suivant son exécution. Le traitement à l’adrénaline n’a pas démontré d’impact significatif (P = 0,845) sur la durée du bloc sensitif, tel qu’évalué par un stimulus douloureux mécanique appliqué aux dermatomes ciblés. À l’opposé, l’atteinte proprioceptive évaluée par la démarche a été trouvée prolongée (P = 0,027) et le bloc moteur mesuré par le pic de force verticale (PVF) au trot sur la plaque de force s’est avéré plus marqué (PVF réduit; P = 0,007) sous LA. À l’arrêt comme au trot, le nadir de la courbe PVF-temps a été trouvé retardé (P < 0,005) et la pente ascendante de retour aux valeurs normales adoucie (P = 0,005). Parallèlement aux évaluations cliniques, des échantillons plasmatiques ont été collectés régulièrement afin de quantifier et décrire le devenir pharmacocinétique de la lidocaïne. Parmi les trois élaborés, un modèle bi-compartimental doté d’une double absorption asynchrone d’ordre zéro a finalement été sélectionné et appliqué aux données expérimentales. Sous LA, la Cmax a été trouvée significativement diminuée (P < 0,001), les phases d’absorption prolongées [P < 0,020 (Dur1) et P < 0,001 (Dur2)] et leurs constantes réduites [P = 0,046(k01) et P < 0,001 (k02)], le tout en concordance avec les effets proprioceptifs et moteurs rapportés. Bien que l’extrapolation du dosage soit maintenant théoriquement envisageable à partir du modèle mis en lumière ici, des études supplémentaires sont encore nécessaires afin d’établir un protocole de PBPB d’intérêt clinique. L’analyse sur plaque de force pourrait alors devenir un outil de choix pour évaluer l’efficacité du bloc dans un cadre expérimental. / Over the last decade, regional anaesthesia has become a gold standard for peri-surgical management in veterinary medicine. Among the many techniques developed for analgesia in dogs, the paravertebral brachial plexus block (PBPB) is of great interest when targeting the proximal half of the thoracic limb. Yet, most available data on this technique is based on colorimetric protocols rather than clinical evaluation, and there are very few published results for PBPB execution using nerve location techniques. Through this work, we wished to describe an ultrasound-guided approach of the PBPB and characterize its pharmacokinetic/ pharmacodynamic parameters when executed with either lidocaine alone (LI) or combined to adrenaline (LA). Eight dogs were included in a prospective, randomised, blinded, crossover protocol performed over three distinct periods. Pharmacodynamic impact of LI and LA was compared for 180 minutes after block administration. No significant difference (P = 0.845) was noted between treatments regarding length of the sensitive block, as evaluated regularly through a mechanical painful stimulus applied to selected dermatomes. On the opposite, gait examination showed a longer proprioceptive deficit using LA (P = 0.027). Motor block measured with dynamic force plate analysis showed a lower peak vertical force with LA than LI (P = 0.007). For both dynamic and static evaluations, nadir was clearly delayed (P < 0.005) and the ascending slope back to baseline significantly softened (P = 0.005) in the LA group. Throughout block execution and evaluation, blood samples were collected regularly in order to quantify and describe lidocaine kinetics. Models where developed and compared. A two-compartment model with dual zero-order absorption processes was selected as the best fit for our experimental data. Cmax proved to be significantly reduced with LA (P < 0.001), thus reducing potential toxicity. Absorption phase was prolonged [P < 0.020 (Dur1) and P < 0.001 (Dur2)] and zero-order absorption constant rates lowered [P = 0.046(k01) and P < 0.001 (k02)] following adrenaline addition, in accordance with the previously noted prolonged gait and motor effects. Though dosage extrapolation is now possible using the model developed and tested here, further studies would be needed to establish a PBPB protocol of more clinical interest. Then, force plate analysis could become a key tool for block quality assessment, as both dynamic and static measurements proved to be the reliable ways to collect ground reaction force (GRF) data.
99

Aspects on wall properties of the brachial artery in man : with special reference to SLE and insulin-dependent diabetes mellitus

Bjarnegård, Niclas January 2008 (has links)
The mechanical properties of the arterial wall are of great importance for blood pressure regulation and cardiac load. With increasing age, large arteries are affected by increased wall stiffness. Furthermore, atherosclerotic manifestations may increase the stiffness even further, both processes acting as independent cardiovascular risk factors affecting the arterial system in a heterogeneous way. The aims of this thesis was to characterize the local mechanical properties of brachial artery (BA) with the aid of ultrasound technique and to evaluate the influence of 1) age, gender, sympathetic stimulation and examination site; 2) type 1 diabetes (DM) and its association to circulatory biomarkers; and 3) to evaluate the general properties of the arterial system with the aid of pulse wave velocity (PWV) as well as pulse wave analysis (PWA) in systemic lupus erythematosus (SLE) and correlate the findings to disease activity and circulatory biomarkers. In the most proximal arterial segment of the upper arm a pronounced age-related decrease in wall distensibility, increase in intima-media thickness (IMT), and a slight increase in diameter were seen. Sympathetic stimulation had no influence on wall mechanics. More distally in BA, no change in diameter, and only minor increase in IMT and decrease in distensibility were seen. No gender differences were found. These findings suggest that the principle transit zone between elastic and muscular artery behaviour is located in the proximal part of the upper arm. Women with uncomplicated insulin-dependent DM had similar diameter, IMT and distensibility in their distal BA as controls, whereas flow-mediated dilatation (FMD) was slightly, and nitrate mediated dilatation (NMD) markedly reduced. NMD was negatively correlated with higher HbA1c levels. Vascular smooth muscle cell function seems to be an early manifestation of vascular disease in women with DM, influenced by long-term hyperglycaemia. Women with SLE had increased aortic PWV compared to controls, a finding positively associated with increased levels of complement factor 3 (C3), but not with disease activity. The increased stiffness of central arteries may be one factor contributing to the increased cardiovascular risk seen in SLE.
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Alterações vasculares em pacientes com doença renal crônica com hiperparatiroidismo secundário / Vascular changes in chronic renal disease patients with secondary hyperparathyroidism

Hong, Valéria Aparecida da Costa 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

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