Suivi de la consolidation des fractures par transmission axiale ultrasonore (effet de la composition et de la minéralisation du cal osseux)

La présente thèse étudie la transmission axiale ultrasonore pour le suivi de la consolidation des fractures osseuses. Premièrement, des simulations numériques couplées à des modèles évolutifs de cals osseux dont la composition tissulaire évolue dans le temps ont permis d évaluer les caractéristiques (atténuation, temps de vol) de l onde transmise au cours de la régénération. Deuxièmement, des mesures ont été effectuées sur un modèle expérimental (os bovin) dans différentes situations (intact, fracturé, différents stades de minéralisation) en utilisant un protocole de déminéralisation de l os cortical pour analyser l effet de la concentration en calcium sur les mesures de temps de vol de l onde transmise. Le contrôle de la déminéralisation a été réalisé en fin de processus par microscopie acoustique. Les résultats de la simulation ont montré que les paramètres ultrasonores sont influencés par la composition tissulaire du cal osseux. Les résultats expérimentaux, en accord avec les prédictions numériques, montrent que le degré de minéralisation est une variable importante, et ils démontrent la sensibilité de la technique aux propriétés du cal osseuxPARIS-BIUSJ-Biologie recherche (751052107) / SudocSudocFranceF

Ultrasonic techniques for medical imaging and tissue characterization

Since the publication of the first edition, the richness of the study of piezoelectric transducers has resulted in a large number of studies dealing both with new understandings underlying the principles, with new technological advances in its applications and indeed with developing new areas of utility for these transducers. The motivations driving the publication of that first edition as described in its foreword (which follows) continues with increased validity. The value of a second edition to include these new developments has been prepared. During the interim, the contributors and their students have not only continued, but increased their mutual interactions resulting in an amazing energy and synergy which is revealed in this edition

Characterization of pseudarthrosis with ultrasound backscattered signals in rats Caracterização da pseudoartrose com sinais de retroespalhamentos de ultrassom em ratos

PURPOSE: To propose a novel model of pseudarthrosis in a small animal and to investigate the ability of backscatter parameters from ultrasound signals in differentiating normal bone from those ones with pseudarthorsis. METHODS: Twelve Rattus norvegicus albinus free from pathogenic species (SPF) were randomly divided in two groups, with six animals each. In the Control group a surgical approach to the femur was made, followed by the synthesis of the muscle and skin layers. The Experimental group was submitted to an osteotomy of the femur and a vascularized flap of the fascia lata was interposed in the line of the fractured bone. Then the alignment and bone stabilization were accomplished, by using nylon stitch in U shape introduced in holes made in the proximal and distal fractured bone. Bone samples were scanned with ultrasound and signals were collected for each one to analyze the parameter Apparent Integrated Backscatter - AIB. RESULTS: Radiological and anatomopathologic studies revealed the absence of bone consolidation with persistence of fiber-osteoid tissue. Values of the ultrasound parameter AIB from normal bones were statistically different from those with pseudarthrosis. CONCLUSION: The experimental model was suitable for pseudarthrosis development in rats and the ultrasound backscatter parameters were able to identify such a bone disease in vitro.<br>OBJETIVO: Propor um novo modelo de pseudoartrose em animais de pequeno porte e investigar o potencial de parâmetros de retroespalhamento de ultrassônico em diferenciar osso normal e com pseudoartrose. MÉTODOS: Doze Rattus norvegicus albinus (SPF) foram distribuídos aleatoriamente em dois grupos, tendo cada grupo seis animais. No grupo Controle realizou-se uma abordagem cirúrgica ao fêmur, seguida da síntese por planos do músculo e da pele. O grupo Experimental foi submetido à osteotomia do fêmur aduzida da confecção de um retalho pediculado de fascia lata para interposição entre os segmentos resultantes da fratura induzida cirurgicamente. Prosseguiu-se com o alinhamento e estabilização óssea, mediante a confecção de um nó com fio de náilon em formato de U, introduzido em orifícios efetuados nas extremidades proximal e distal à fratura. As amostras ósseas foram irradiadas pelo ultrassom e sinais foram coletados para cada uma no intuito de analisar o parâmetro Retroespalhamento Integrado Aparente - AIB. RESULTADOS: Estudos radiológicos e anatomopatológicos evidenciaram a ausência de consolidação óssea com persistência de tecido fibro-osteóide. Os valores de AIB para ossos normais foram estatisticamente diferentes em relação aos ossos com pseudoartrose. CONCLUSÃO: O modelo experimental apresentou-se adequado para a formação de pseudoartrose em ratos e o parâmetro de retroespalhamento de ultrassom foi capaz de detectar tal doença óssea, in vitro

Whole-body vibration improves the functional parameters of individuals with metabolic syndrome: an exploratory study

Abstract Background Metabolic syndrome (MetS) is a cluster of metabolic abnormalities that increases the cardiovascular risk. Regular physical exercise can promote benefits, but the MetS individuals are demotivated to perform it. Thus, new possibilities are important as an alternative intervention. The whole-body vibration can be considered an exercise modality and would be a safe and low-cost strategy to improve functional parameters of individuals in different clinical conditions. The aim of this exploratory study was to assess effects of whole-body vibration on functional parameters of MetS individuals. The hypothesis of this work was that the whole-body vibration could improve the functionality of MetS individuals. Methods Twenty-two individuals performed the intervention. The vibration frequency varied from 5 to 14 Hz and the peak-to-peak displacements, from 2.5 to 7.5 mm. Each session consisted of one minute-bout of working time followed by a one minute-bout of passive rest in each peak-to-peak displacement for three-times. The whole-body vibration protocol was applied twice per week for 5 weeks. Data from the trunk flexion, gait speed, sit-to-stand test and handgrip strength were collected. Physiological parameters (blood pressure and heart rate) were also evaluated. The Wilcoxon Rank test and Student t-test were used. Results No significant changes (p > 0.05) were observed in physiological parameters (arterial blood pressure and heart rate). Significant improvements were found in trunk flexion (p = 0.01), gait speed (p = 0.02), sit-to-stand test (p = 0.005) and handgrip strength (p = 0.04) after the whole-body vibration. Conclusions In conclusion, whole-body vibration may induce biological responses that improve functional parameters in participants with MetS without interfering in physiological parameters, comparing before and after a 5-week whole-body vibration protocol. Trial registration Register in the Registro Brasileiro de Ensaios Clínicos (ReBEC) with the number RBR 2bghmh (June 6th, 2016) and UTN: U1111–1181-1177. (virgula)