• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 88
  • 58
  • 39
  • 25
  • 18
  • 10
  • 9
  • 7
  • 6
  • 6
  • 4
  • 3
  • 2
  • 1
  • 1
  • Tagged with
  • 311
  • 75
  • 72
  • 71
  • 60
  • 48
  • 48
  • 44
  • 43
  • 42
  • 42
  • 41
  • 40
  • 38
  • 31
  • 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.
191

Développement et validation d’un outil clinique pour l’analyse quantitative de la posture auprès de personnes atteintes d’une scoliose idiopathique

Fortin, Carole 06 1900 (has links)
La scoliose idiopathique (SI) est une déformation tridimensionnelle (3D) de la colonne vertébrale et de la cage thoracique à potentiel évolutif pendant la croissance. Cette déformation 3D entraîne des asymétries de la posture. La correction de la posture est un des objectifs du traitement en physiothérapie chez les jeunes atteints d’une SI afin d’éviter la progression de la scoliose, de réduire les déformations morphologiques et leurs impacts sur la qualité de vie. Les outils cliniques actuels ne permettent pas de quantifier globalement les changements de la posture attribuables à la progression de la scoliose ou à l’efficacité des interventions thérapeutiques. L’objectif de cette thèse consiste donc au développement et à la validation d’un nouvel outil clinique permettant l’analyse quantitative de la posture auprès de personnes atteintes d’une SI. Ce projet vise plus spécifiquement à déterminer la fidélité et la validité des indices de posture (IP) de ce nouvel outil clinique et à vérifier leur capacité à détecter des changements entre les positions debout et assise. Suite à une recension de la littérature, 34 IP représentant l’alignement frontal et sagittal des différents segments corporels ont été sélectionnés. L’outil quantitatif clinique d’évaluation de la posture (outil 2D) construit dans ce projet consiste en un logiciel qui permet de calculer les différents IP (mesures angulaires et linéaires). L’interface graphique de cet outil est conviviale et permet de sélectionner interactivement des marqueurs sur les photographies digitales. Afin de vérifier la fidélité et la validité des IP de cet outil, la posture debout de 70 participants âgés entre 10 et 20 ans atteints d'une SI (angle de Cobb: 15º à 60º) a été évaluée à deux occasions par deux physiothérapeutes. Des marqueurs placés sur plusieurs repères anatomiques, ainsi que des points de référence anatomique (yeux, lobes des oreilles, etc.), ont permis de mesurer les IP 2D en utilisant des photographies. Ces mêmes marqueurs et points de référence ont également servi au calcul d’IP 3D obtenus par des reconstructions du tronc avec un système de topographie de surface. Les angles de Cobb frontaux et sagittaux et le déjettement C7-S1 ont été mesurés sur des radiographies. La théorie de la généralisabilité a été utilisée pour déterminer la fidélité et l’erreur standard de la mesure (ESM) des IP de l’outil 2D. Des coefficients de Pearson ont servi à déterminer la validité concomitante des IP du tronc de l’outil 2D avec les IP 3D et les mesures radiographiques correspondantes. Cinquante participants ont été également évalués en position assise « membres inférieurs allongés » pour l’étude comparative de la posture debout et assise. Des tests de t pour échantillons appariés ont été utilisés pour détecter les différences entre les positions debout et assise. Nos résultats indiquent un bon niveau de fidélité pour la majorité des IP de l’outil 2D. La corrélation entre les IP 2D et 3D est bonne pour les épaules, les omoplates, le déjettement C7-S1, les angles de taille, la scoliose thoracique et le bassin. Elle est faible à modérée pour la cyphose thoracique, la lordose lombaire et la scoliose thoraco-lombaire ou lombaire. La corrélation entre les IP 2D et les mesures radiographiques est bonne pour le déjettement C7-S1, la scoliose et la cyphose thoracique. L’outil est suffisamment discriminant pour détecter des différences entre la posture debout et assise pour dix des treize IP. Certaines recommandations spécifiques résultents de ce projet : la hauteur de la caméra devrait être ajustée en fonction de la taille des personnes; la formation des juges est importante pour maximiser la précision de la pose des marqueurs; et des marqueurs montés sur des tiges devraient faciliter l’évaluation des courbures vertébrales sagittales. En conclusion, l’outil développé dans le cadre de cette thèse possède de bonnes propriétés psychométriques et permet une évaluation globale de la posture. Cet outil devrait contribuer à l’amélioration de la pratique clinique en facilitant l’analyse de la posture debout et assise. Cet outil s’avère une alternative clinique pour suivre l’évolution de la scoliose thoracique et diminuer la fréquence des radiographies au cours du suivi de jeunes atteints d’une SI thoracique. Cet outil pourrait aussi être utile pour vérifier l’efficacité des interventions thérapeutiques sur la posture. / Idiopathic scoliosis (IS) is characterized by three-dimensional (3D) deformity of the spine and rib cage which can increase during growth. The morphologic changes of the trunk result in posture asymmetries. Correction of posture is an important goal of physiotherapy interventions among persons with IS to prevent scoliosis progression, to reduce morphologic deformities and their impact on quality of life. Currently, there are no tools that globally quantify changes in posture that may be attributable to scoliosis progression or to treatment effectiveness, that are usable in a clinical setting. The objective of this thesis was thus to develop and validate a new clinical quantitative posture assessment tool among persons with IS. More specifically, this project aims to determine reliability and concurrent validity of posture indices (PI) of this new tool and to verify their capacity to detect changes between standing and sitting positions. We conducted a literature review and selected 34 PI representing frontal and sagittal alignment of the different body segments. We constructed a software-based quantitative posture assessment tool to calculate different PI (angular and linear measurements). The software has a user-friendly graphical interface and allows calculation of PI from a set of markers selected interactively on digital photographs. For the reliability and validity studies, standing posture of 70 participants aged 10 to 20 years old with IS (Cobb angle: 15º to 60º) was assessed on two occasions by two physiotherapists. Markers placed on several bony landmarks as well as natural reference points (eyes, ear lobe, etc.) were used to measure the PI from photographs with the 2D tool and to calculate 3D PI obtained from trunk reconstructions with a surface topography system. Frontal and sagittal Cobb angles and trunk list were also calculated on radiographs. The generalizability theory was used to estimate the reliability and standard error of measurement (SEM) of PI of the 2D tool. Pearson correlation coefficients served to estimate concurrent validity of the 2D trunk PI with corresponding 3D PI and with those obtained from radiographs. Fifty participants were assessed for the comparative study between standing and sitting positions. We compared the average values of each PI in standing and long sitting positions using paired t-tests. Our results show a good level of reliability for the majority of PI of the 2D tool. Correlation between 2D and 3D PI was good for shoulder, scapula, trunk list, waist angles, thoracic scoliosis and pelvis but fair to moderate for thoracic kyphosis, lumbar lordosis and thoracolumbar or lumbar scoliosis. The correlation between 2D and radiograph measurements was good for trunk list, thoracic scoliosis and thoracic kyphosis. Our tool can detect differences between standing and sitting posture for ten out of thirteen PI. A few recommendations specific to this work are: camera height should be adjusted according to the subject’s height; training of judges is important to maximize accuracy in placement of markers; and measurement of sagittal vertebral curves may be facilitated by using markers mounted on pins. In conclusion, the tool developed in this thesis has good psychometric properties to evaluate posture. This tool should contribute to clinical practice by facilitating the analysis of standing and sitting posture. This tool may also be a good alternative to monitor thoracic scoliosis progression in a clinical setting and may contribute to a reduction in the use of x-rays in the follow-up of youths with thoracic IS. It may also be useful to verify the effectiveness of therapeutic interventions on posture.
192

Morphologie tridimensionnelle du bassin scoliotique

Santucci Ribeiro, Camila 10 1900 (has links)
La scoliose idiopathique de l’adolescence (SIA) est une déformation tridimensionnelle de la colonne vertébrale et de la cage thoracique dont la cause est inconnue. Il semble que la ceinture pelvienne soit impliquée dans la pathogénie de la SIA, car des différences géométriques des os coxaux ont été observées. Notamment, une rotation du bassin ou une inclinaison latérale dans le sens de la courbe scoliotique ont été mises en évidence en plus des distorsions osseuses. Il est difficile de dissocier la rotation du bassin de son asymétrie, car la majorité des études porte sur des données radiologiques bidimensionnelles. Une analyse tridimensionnelle de la morphologie du bassin de patientes ayant une SIA, mais n’ayant pas reçu de traitement par corset ou chirurgie permettrait d’identifier le rôle du bassin dans la progression de la scoliose. Dix-sept jeunes filles atteintes de la SIA ont participé à cette étude pour lesquelles des radiographies bi-planaires en station debout étaient disponibles au moment du diagnostic par un chirurgien orthopédiste pédiatrique et à l’instant de la prescription d'un corset. Des radiographies postéro-antérieures et latérales avaient été prises au moyen du système EOS®. Douze repères anatomiques du bassin ont été identifiés sur les paires de radiographies, alors que quatre repères ont été identifiés sur la radiographie postéro-antérieure uniquement. Ces quatre derniers n’étaient pas identifiables sur la radiographie latérale à cause de la superposition des repères droits et gauches. La reconstruction tridimensionnelle du bassin a été réalisée à partir de deux clichés radiographiques des 12 premiers repères osseux. Au total, neuf paramètres tridimensionnels ont été calculés afin de quantifier l’asymétrie et la distorsion du bassin entre les deux temps donnés. Des paramètres bidimensionnels ont également été mesurés sur les quatre derniers repères osseux afin de documenter des déformations du bassin pertinentes à la pratique clinique, telle que la rotation axiale de celui-ci. Dans le but d'évaluer une possible asymétrie entre les os coxaux du bassin, les paramètres tridimensionnels du bassin gauche ont été comparés à ceux du côté droit à chaque temps, au moyen d'un test-t pour échantillon apparié. La morphologie pelvienne a été également évaluée par l'analyse multivariée (MANOVA) à mesures répétées à deux conditions (côté*temps). En conséquence, nous avons constaté une croissance osseuse statistiquement significative du bassin dans l’intervalle de temps entre le diagnostic de la scoliose et le port du corset (p=0,033). Une asymétrie significative entre les côtés gauche et droit du bassin (p=0,013) a également été constatée. En ce qui concerne les paramètres bidimensionnels, nous avons constaté une augmentation de la version pelvienne (p=0,024) au cours de la croissance des jeunes filles. Finalement, le bassin n'a pas présenté de distorsion, puisqu'une valeur de p de 0,763 a été observée. En conclusion, la croissance des jeunes filles atteintes de la scoliose idiopathique de l'adolescence est accompagnée d'une asymétrie morphologique entre les deux os coxaux du bassin. Cette asymétrie constatée au moment du diagnostic de la scoliose des filles a évolué jusqu'à l’instant où le port du corset a été prescrit. Quant aux paramètres bidimensionnels, nous pouvons conclure que la rotation du bassin vers l'arrière a augmenté au cours de la croissance des jeunes filles, produisant ainsi une rétroversion pelvienne dans le plan sagittal. La distorsion tridimensionnelle du bassin n'a toutefois pas été observée au cours de la croissance des jeunes filles. / Adolescent idiopathic scoliosis (AIS) is a three-dimensional deformation of the spine and rib cage of unknown cause. It seems that the pelvis is involved in the pathogenesis of the AIS because geometric differences in the hip bones were observed. A pelvic rotation or a lateral tilt in the direction of the scoliotic curve was observed in addition to bone distortions. It is difficult to separate the pelvic rotation from its asymmetry since most studies are based on bi-dimensional radiologic data. A three-dimensional analysis of the pelvis morphology in patients with AIS, but no brace treatment nor surgery could better define the role of pelvis in the progression of the scoliosis. Seventeen young girls with AIS have participated in this study. Standing bi-planer radiographs were available at the time of diagnosis by a pediatric orthopedic surgeon and at the moment of the brace prescription. Postero-anterior and lateral X-rays were taken using the EOS® system. Twelve anatomical landmarks of the pelvis were identified on the radiograph pairs and four landmarks were identified on the postero-anterior radiography only. These were not identified on the lateral radiograph due to the superposition of the right and left landmarks. The three-dimensional reconstruction of the pelvis was performed using two radiographs of the first 12 bony landmarks. A total of nine three-dimensional parameters were calculated to quantify the asymmetry of the pelvis distortion between the two given times. Bi-dimensional parameters were also measured on the last four bony landmarks in order to document the pelvic deformations relevant to the clinical practice such as the rotation. With the objective of evaluating a possible asymmetry between the hip bones of the pelvis, the three-dimension parameters of the left pelvis were compared to those of the right side in each time using a paired sample t-test. The pelvic morphology was also evaluated using a multivariate analysis (MANOVA) with repeated measures on two conditions (side*time). A statistically significant bone growth of the pelvis in the time interval between the diagnosis of the scoliosis and the brace prescription (p=0.033) was observed in consequence. A significant asymmetry between the left and right sides of the pelvis (p=0.013) without distortion was also observed. Regarding the bi-dimensional parameters, we found an increase in pelvic release (p=0.024) during the growth of the girls. Finally, the pelvis did not show a distortion because a p value of 0.763 was observed. In conclusion, the growth of young girls with adolescent idiopathic scoliosis is related to a morphological asymmetry between the two hipbones of the pelvis. This asymmetry observed at the moment of the scolioisis diagnosis has evolved until de moment of the brace prescription. As for the bi-dimensional parameters, we can conclude that the rotation of the pelvis to the back increased during the growth of the girls, producing a pelvic retroversion in the sagittal plan. The three-dimensional distortion of the pelvis, however, has not been observed during the young girls growth.
193

Une nouvelle méthode pour estimer la torsion géométrique en scoliose idiopathique de l’adolescent

Shen, Jesse 12 1900 (has links)
La scoliose idiopathique de l’adolescent (SIA) est une déformation tridimensionnelle (3D) de la colonne vertébrale. Pour la plupart des patients atteints de SIA, aucun traitement chirurgical n’est nécessaire. Lorsque la déformation devient sévère, un traitement chirurgical visant à réduire la déformation est recommandé. Pour déterminer la sévérité de la SIA, l’imagerie la plus utilisée est une radiographie postéroantérieure (PA) ou antéro-postérieure (AP) du rachis. Plusieurs indices sont disponibles à partir de cette modalité d’imagerie afin de quantifier la déformation de la SIA, dont l’angle de Cobb. La conduite thérapeutique est généralement basée sur cet indice. Cependant, les indices disponibles à cette modalité d’imagerie sont de nature bidimensionnelle (2D). Celles-ci ne décrivent donc pas entièrement la déformation dans la SIA dû à sa nature tridimensionnelle (3D). Conséquemment, les classifications basées sur les indices 2D souffrent des mêmes limitations. Dans le but décrire la SIA en 3D, la torsion géométrique a été étudiée et proposée par Poncet et al. Celle-ci mesure la tendance d’une courbe tridimensionnelle à changer de direction. Cependant, la méthode proposée est susceptible aux erreurs de reconstructions 3D et elle est calculée localement au niveau vertébral. L’objectif de cette étude est d’évaluer une nouvelle méthode d’estimation de la torsion géométrique par l’approximation de longueurs d’arcs locaux et par paramétrisation de courbes dans la SIA. Une première étude visera à étudier la sensibilité de la nouvelle méthode présentée face aux erreurs de reconstructions 3D du rachis. Par la suite, deux études cliniques vont présenter la iv torsion géométrique comme indice global et viseront à démontrer l’existence de sous-groupes non-identifiés dans les classifications actuelles et que ceux-ci ont une pertinence clinique. La première étude a évalué la robustesse de la nouvelle méthode d’estimation de la torsion géométrique chez un groupe de patient atteint de la SIA. Elle a démontré que la nouvelle technique est robuste face aux erreurs de reconstructions 3D du rachis. La deuxième étude a évalué la torsion géométrique utilisant cette nouvelle méthode dans une cohorte de patient avec des déformations de type Lenke 1. Elle a démontré qu’il existe deux sous-groupes, une avec des valeurs de torsion élevées et l’autre avec des valeurs basses. Ces deux sous-groupes possèdent des différences statistiquement significatives, notamment au niveau du rachis lombaire avec le groupe de torsion élevée ayant des valeurs d’orientation des plans de déformation maximales (PMC) en thoraco-lombaire (TLL) plus élevées. La dernière étude a évalué les résultats chirurgicaux de patients ayant une déformation Lenke 1 sous-classifiées selon les valeurs de torsion préalablement. Cette étude a pu démontrer des différences au niveau du PMC au niveau thoraco-lombaire avec des valeurs plus élevées en postopératoire chez les patients ayant une haute torsion. Ces études présentent une nouvelle méthode d’estimation de la torsion géométrique et présentent cet indice quantitativement. Elles ont démontré l’existence de sous-groupes 3D basés sur cet indice ayant une pertinence clinique dans la SIA, qui n’étaient pas identifiés auparavant. Ce projet contribue dans la tendance actuelle vers le développement d’indices 3D et de classifications 3D pour la scoliose idiopathique de l’adolescent. / Adolescent idiopathic scoliosis (AIS) is a three dimensional (3D) deformity of the spine. For most patients, no surgical intervention is required. However, for patients with severe deformities, surgery is often recommended. Postero-anterior (PA) and antero-posterior (AP) x-rays are the most common modality for viewing and evaluating this deformity. From this imaging modality, clinical indices such as the Cobb angle can quantify and evaluate the severity of AIS. Clinical decision making is often based on this descriptor. However, the descriptors based on spinal radiographies are two- dimensional (2D) by nature. Therefore, they do not fully describe the deformity in AIS due to its three-dimensional (3D) nature. Poncet et al. have studied and presented geometric torsion as a 3D descriptor of AIS. This index measures a curve’s tendency to twist out of a plane. However, the method presented in their study is susceptible to errors from an imperfect 3D spinal reconstruction due to the local approach taken and is presented in a qualitative fashion. Hence, the objective of this study is to evaluate a new method of estimating geometric torsion in AIS employing parametric curve fitting techniques based on local arc-length approximations. The first study attempts to evaluate the sensitivity of the presented method of estimating geometric torsion against noisy data or 3D reconstruction errors. Two clinical studies will then present this descriptor as a quantitative measurement of AIS and will attempt to identify potential new sub-groups and demonstrate the clinical relevance of these new sub-groups. vi The first study evaluated the robustness of the new method in estimating geometric torsion in the presence of reconstruction errors. This study demonstrated that the new method is robust to 3D spinal reconstruction errors and achieves quantitative measures in a global fashion. The second study evaluated this new method of estimating geometric torsion in patients with Lenke type 1 deformities. This study identified two sub-groups based on torsion values, a high torsion and a low torsion group. These two sub-groups showed differences in the orientation of the planes of maximum deformity (PMC) in the thoraco-lumbar segment of the spine with the high torsion group having greater values. The last study evaluated the surgical results of patients with Lenke type 1 deformities having been sub-classified in high and low torsion groups. This study showed differences in TLL PMC with the high torsion group of patients having higher values pre and post-operatively, These studies present a novel method of estimating geometric torsion in AIS and present this 3D descriptor quantitatively. They have demonstrated the existence of new sub-groups within current classification systems that were previously undetected and have shown the clinical relevance of this new method of estimating geometric torsion in AIS. This project contributes towards the development of new 3D indices for AIS and opens the door to potential new 3D classifications.
194

Neideální vývoj kyčelního kloubu jako faktor vzniku idiopatické skoliózy / Non-ideal development of the hip joint as a forming factor of idiopathic scoliosis

Fišerová, Eva January 2010 (has links)
The thesis deals with connections between non-ideal development of the hip joint and origin of idiopathic scoliosis. The thesis warn that asymmetry in neuromotor ontogenesis is a risk factor for development of scoliosis. There is also summary of abnormalities in hip joints which are connected with idiopatic scoliosis. In experimental part of the work it has been confirmed that patient with idiopathic scoliosis have leftright asymmetry of the range of movement in hip joints. This asymmetries are discussed in the context of both the etiopathogenezis and the effect of spinal deformity. Powered by TCPDF (www.tcpdf.org)
195

Dynamické vyšetření Moiré a Pedoscan u pacientů se skoliózou / Moiré and Pedoscan dynamic examinations of patients with scoliosis

Klímová, Michaela January 2015 (has links)
Scoliosis is the most common deformity of the spine affecting from 3 to 6% of human population. The thesis "Moiré and Pedoscan dynamic examinations of patients with scoliosis" summarizes the findings of kinesiology of the spine, pelvis and hip joints and ontogenesis of axial organ straightening. It also deals with the issue of idiopathic scoliosis, its incidence, etiology, classification, diagnosis, treatment options and applied physiotherapy methods. The paper emphasizes the influence of physiotherapy that forms an integral part of medical treatment. A great part of the thesis is devoted to the rasterstereographic and pedobarographic examination. The main purpose of this thesis was to detect and evaluate parameters assessing posture and movement of patients suffering from scoliosis and compare them with a control group. For this purpose, a pedobarographic system Diers pedoscan was used, which detected the distribution of compressive forces on the feet when walking and standing. It was also used a rasterstereographic system Diers formetric III 4D, which allowed for capturing photogrammetric recording of the spine and pelvis using a video-rasterstereography based on the Moiré topography. The study was carried out with a group of 22 females with idiopathic scoliosis up to 40ř according to Cobb aged...
196

Analýza stoje a chůze s využitím ZEBRIS FDM-T systému u pacientů se skoliózou / Stance and gait analysis using ZEBRIS FDM-T System in patients with scoliosis

Bulánová, Kateřina January 2016 (has links)
The thesis deals with the issue of walking and standing in patients with a scoliosis. The theoretical part of this thesis summarizes current knowledge of scoliosis, its classification, etiology, pathogenesis and risk factors of the curve progression. Then the most often changes of the stand and gait stereotype and their main causes are discussed. Goal of the practical part was to identify the difference between particular parameters of gait in an experimental group of patients with scoliosis and a control group of healthy individuals. The examination was performed via the dynamic plantography method using the Zebris FDM-T System. 19 probands with scoliosis aged 8 - 19 and a control group of 19 orthopedically healthy patients in a corresponding age distribution have been selected for the study. The results did not provide any statistically significant difference on a significance level p=0,05. However, there were clear differences between the groups referring to bigger asymmetries in stance and gait stereotype in the scoliosis patients group. Since even in a scientific literature there is a difference in opinion on this issue, more research might be necessary for the exact evaluation of the influence of scoliosis on the stance and gait stereotype.
197

Rôle de la voie hedgehog dans la fibrose pulmonaire idiopathique / Implication of the Hedgehog pathway in pulmonary idiopathic fibrosis

Farrokhi Moshai, Elika 19 December 2013 (has links)
La Fibrose Pulmonaire Idiopathique (FPI) est une maladie dévastatrice, d’étiologie inconnue, qui reste pour le moment incurable. Cette maladie est caractérisée par l’accumulation de fibroblastes et de protéines de la matrice extracellulaire dans les espaces aériens distaux aboutissant à une destruction alvéolaire et à une altération des propriétés mécaniques du poumon. La physiopathologie de la FPI est mal connue mais de nombreuses études suggèrent que la réactivation des voies impliquées dans le développement contribue à l’accumulation de la matrice extra-cellulaire et au comportement anormal des cellules épithéliales et des fibroblastes.La voie Hedgehog (HH) joue un rôle crucial dans le développement embryonnaire. Dans le développement pulmonaire fœtal, la voie HH est impliquée dans les interactions épithélium-fibroblaste et contrôle la prolifération et la différenciation du mésenchyme. La voie HH a été impliquée dans la fibrogénèse, notamment dans le foie et le rein.L’objectif de cette thèse a été de caractériser la voie HH dans la fibrose pulmonaire chez l’homme et dans un modèle de fibrose induite par la bléomycine chez la souris.Nous avons démontré que la voie HH est réactivée dans les tissus pulmonaires de patients atteints de FPI et dans le modèle de fibrose pulmonaire chez la souris. Nous avons montré que le TGF-β1 activait la voie HH dans les fibroblastes pulmonaires humains et que l’inhibition pharmacologique de la voie HH au niveau des facteurs GLI inhibait l’effet du TGF-β1 in vitro. Par contre, ces inhibiteurs ne protégent pas les cellules épithéliales alvéolaires de la transition épithélio-mésenchymateuse induite par le TGF-β1. In vivo, chez la souris, nous avons montré que le traitement par des inhibiteurs de Smoothened ne protégeait pas du développement de la fibrose tandis que le GANT61, un inhibiteur de l’interaction des GLI avec l’ADN, inhibait la fibrose.En conclusion, nos résultats démontrent l’implication de la voie HH dans la fibrose pulmonaire et ouvrent des perspectives thérapeutiques nouvelles. / Idiopathic Pulmonary Fibrosis (IPF ) is a devastating disease of unknown etiology, which no efficient treatment. This disease is characterized by the accumulation of fibroblasts and extracellular matrix proteins in the distal airways resulting to the destruction of alveoli and alteration of mechanical properties of the lung. The pathogenesis of IPF is not well known but many studies suggest that reactivation of pathways involved in the development, contributes to the accumulation of extracellular matrix and the abnormal behavior of epithelial cells and fibroblasts.The Hedgehog pathway (HH) plays a crucial role in embryonic development. In the fetal lung development, the HH pathway is involved in the epithelial-fibroblast interactions and controls the proliferation and differentiation of the mesenchyme. The HH pathway has been implicated in the fibrogenesis, particularly in the liver and kidney.The aim of this thesis was to characterize the HH pathway in pulmonary fibrosis in humans and in a model of bleomycin-induced fibrosis in mice.We demonstrated that the HH pathway is reactivated in lung tissue of IPF patients and in the model of pulmonary fibrosis in mice. We have shown that TGF-β1 activated the HH pathway in human lung fibroblasts and that the pharmacological inhibition of the HH pathway at the level of GLI transcription factors, inhibited the effect of TGF-β1 in vitro. By contrast, these inhibitors did not protect alveolar epithelial cells from TGF-β1-induced epithelial-mesenchymal transition. In vivo, we have shown that treatment with Smoothened inhibitors did not protect mice from the development of fibrosis while GANT61, an inhibitor of the GLI interaction with DNA, inhibited fibrosis .In conclusion, our results demonstrate the involvement of the HH pathway in pulmonary fibrosis and open new therapeutic perspectives.
198

Sequenciamento paralelo em larga escala de genes candidatos para fragilidade óssea em indivíduos com osteoporose grave, familiar ou idiopática / Massively parallel sequencing of candidate genes for bone fragility in subjects with severe, familial or idiopathic osteoporosis

Braz, Manuela Giuliani Marcondes Rocha 07 June 2018 (has links)
A osteoporose é uma doença de alta prevalência na população geral, e a ocorrência de fraturas se associa a grande morbi-mortalidade e impacto econômico. Na maioria dos indivíduos afetados, a osteoporose tem etiologia multifatorial, com herdabilidade estimada entre 50 e 85%, atribuível a um conjunto de variantes genéticas de pequeno efeito individual. Raramente, há casos de osteoporose associada a síndromes monogênicas, decorrentes de defeitos genéticos de grande impacto. Postula-se que indivíduos com quadros extremos de osteoporose não sindrômica possam ter causa genética mono- ou oligogênica, atribuível a variantes de impacto intermediário sobre o fenótipo, ainda pouco reconhecidas. Nos últimos anos, o avanço das tecnologias de sequenciamento permitiu o reconhecimento de novos genes associados à fragilidade óssea e atualmente possibilita a análise simultânea de múltiplos genes. Neste contexto, os objetivos deste projeto de pesquisa foram: 1) buscar genes candidatos para fragilidade óssea previamente associados a doenças Mendelianas com alto impacto na resistência óssea, fenótipos extremos de osteoporose e estudos de associação genética em escala genômica (GWAS) para osteoporose; e 2) pesquisar a presença de variantes alélicas patogênicas nestes genes candidatos em indivíduos com osteoporose grave, familiar ou idiopática. A partir de revisão sistemática, 128 genes candidatos foram selecionados para compor um painel de sequenciamento paralelo em larga escala. O sequenciamento incluiu todos os éxons e 25 pares de bases das junções íntron-éxon. Foram consideradas variantes genéticas de interesse aquelas raras (frequência alélica < 1%) e com predição de alto impacto sobre a proteína codificada. Trinta e sete indivíduos (7 famílias e 21 casos isolados) foram selecionados seguindo critérios clínicos, laboratoriais e densitométricos restritivos, excluindo-se pacientes com causas secundárias de osteoporose. A coorte foi composta por homens em 54%, a mediana de idade ao diagnóstico foi 44 anos e 86% tinham histórico de fratura. Dentre os 28 casos índices, foram identificadas 33 variantes de interesse. Após análise de segregação familiar, foi possível excluir patogenicidade de cinco destas variantes, restando 28 variantes potencialmente patogênicas, presentes em 71% da coorte. Todas as variantes foram encontradas em heterozigose, sendo 26 variantes de ponto não-sinônimas, uma deleção de 9 pares de bases, e uma grande deleção envolvendo o único éxon codificador do gene candidato GPR68. Foi encontrada uma associação de variantes em genes diferentes em 21% da coorte, incluindo uma mulher jovem com osteoporose grave e variantes em WNT1, PLS3 e NOTCH2. A análise de segregação familiar neste caso sugeriu um efeito patogênico aditivo das variantes. Vinte e cinco porcento das variantes potencialmente patogênicas foram identificadas em genes candidatos bem estabelecidos (WNT1, PLS3, COL1A1, COL1A2), e 57% se localizam em novos genes candidatos identificados inicialmente por GWAS, como NBR1 e GPR68, também associados à alteração da remodelação óssea em modelos animais. Os resultados deste trabalho dão relevância a novos genes na fisiologia da resistência óssea e indicam um papel proeminente de interações digênicas/oligogênicas em casos de osteoporose grave, familiar ou idiopática. O reconhecimento de novas vias associadas à fragilidade óssea pode levar ao desenvolvimento de novos tratamentos, e a identificação de variantes patogênicas associadas à osteoporose pode, futuramente, permitir um manejo clínico personalizado de pacientes e seus familiares / Osteoporosis is a highly prevalent disorder resulting in fragility fractures and incurring in great morbi-mortality and economic burden. In most cases, osteoporosis has a multifactorial etiology, with an estimated heritability of 50-85% attributable to a combination of several low-impact genetic variants. Rarely, cases of syndromic osteoporosis due to high-impact genetic defects are seen. It is therefore hypothesized that severe/idiopathic cases of otherwise inconspicuous osteoporosis may have a monoor oligogenic etiology due to genetic variants with an intermediate effect. During the past years, advances in molecular sequencing have revealed novel candidate genes for bone fragility, and have enabled simultaneous sequencing of multiple genes. In this context, the objectives of this research project were: 1) to identify candidate genes for bone fragility, as previously reported in association to Mendelian disorders with high impact on bone resistance, idiopathic or familial osteoporosis, and genome-wide association studies (GWAS) for bone mineral density and fragility fractures; and 2) to perform molecular analysis of these candidate genes in patients with severe, familial or idiopathic osteoporosis. Through a systematic review, 128 candidate genes were identified and included in a panel for massively parallel sequencing. Coding regions and 25-bp boundaries were captured and sequenced. Rare variants (allele frequency < 1%), with a predicted high impact on protein function were initially selected as variants of interest. Thirty-seven subjects (21 sporadic cases and 7 families) were included according to stringent criteria based on clinical and densitometric evaluation, excluding individuals with secondary osteoporosis. Males represented 54% of the cohort, median age at diagnosis was 44 years, and 84% of subjects had a history of fractures. Thirtythree variants of interest were identified initially. After familial segregation analysis, 5 variants were considered as benign in regard to bone fragility, resulting in 28 potentially pathogenic variants, all heterozygous, present in 71% of the cohort. Of these variants, 26 were nonsynonymous, there was one 9-bp deletion and one large deletion involving the only coding exon of candidate gene GPR68. An association of two or more variants in different genes was present in 21% of the cohort, including a young woman with severe osteoporosis and variants in WNT1, PLS3 and NOTCH2. Familial segregation in this case suggested an additive pathogenic effect of these variants. Twenty-five percent of potentially pathogenic variants were identified in well-established candidate genes (WNT1, PLS3, COL1A1, COL1A2), and 57% located to novel candidate genes initially identified by GWAS, such as NBR1 and GPR68, which have been previously associated to changes in bone remodeling in mouse models. These results support the involvement of GWAS genes in the pathophysyiology of osteoporosis, and indicate a prominent role for digenic/oligogenic interactions in cases of severe, familial or idiopathic osteoporosis. Recognition of new molecular pathways in the determination of bone fragility may lead to the development of new drugs, and the identification of pathogenic variants associated to osteoporosis may allow individualized clinical management of patients and their relatives
199

Estudo dos fatores regulatórios e pró-inflamatórios na urticária crônica idiopática e efeito imunomodulatório in vitro das estatinas / Study of regulatory and proinflammatory factors in chronic idiopathic urticaria and in vitro immunomodulatory effect of statins

Azor, Mayce Helena 12 August 2010 (has links)
INTRODUÇÃO: A urticária crônica igmaidiopática (UCI) é uma doença desencadeada pela desgranulação de basófilos e mastócitos com consequente liberação de histamina, sendo que o perfil imunológico nesta doença não é bem estabelecido. As estatinas, inibidores da 3-hidroxi-3-metilglutaril coenzima A redutase, apresentam efeitos antiinflamatórios e imunomodulatórios. O efeito desta droga tem sido estudado em muitas doenças inflamatórias crônicas, incluindo doenças autoimunes, mas não existem evidências na UCI. OBJETIVOS: O objetivo deste estudo foi analisar o efeito das estatinas na resposta imune e sua a influência na expressão de genes regulatórios e relacionados com a resposta inflamatória. MÉTODOS: A resposta limfoproliferativa a mitógenos e antígeno-específica de 22 pacientes com UCI e 41 controles na presença de estatinas (0,25-25 µM) foi analisada pela incorporação de timidina após 3 ou 6 dias de cultura. A progressão do ciclo celular e apoptose foi realizada pela incorporação de bromodeoxiuridina (Brdu) ao DNA após estímulo por PHA ou PWM e analisada por citometria de fluxo. A secreção de citocinas foi quantificada por ELISA e a expressão de mRNA de fatores regulatórios e pró-inflamatórios quantificados por real-time PCR. RESULTADOS: Os resultados evidenciaram que as estatinas em elevadas concentrações são capazes de inibir a capacidade mitogênica das células T e B seja dos indivíduos saudáveis ou de pacientes com UCI. A inibição da proliferação celular mediada pelas estatinas foi decorrente ao bloqueio na etapa inicial do ciclo celular (Fase G0/1), o que impediu o prosseguimento para outras fases do ciclo (S e G2/M). A diminuição da resposta proliferativa em resposta a um mitógeno como a PHA resultou na inibição da ativação celular pela estatina e a significante redução na produção de citocinas como IFN-?, IL-10, IL-17A e IL-5. Em contraste, o efeito modulatório das estatinas ao estímulo com LPS inibiu a produção de TNF-? e MIP-1? pelas células dos controles, mas não influenciou na produção de citocinas pró-inflamatórias pelas CMN dos pacientes com UCI. Somente a incubação prévia das células com as drogas, em alta concentração (25µM), foi possível verificar a modulação negativa na produção de IL-6 e MIP1-? para ambos os grupos, mas não para o TNF-? para os pacientes. A sinvastatina foi capaz exercer efeito modulatório mais pronunciado que a lovastatina na produção de citocinas induzidas por LPS. Os resultados evidenciaram que os pacientes com UCI possuem uma diminuição da expressão da enzima IDO e aumento de SOCS3 nas CMN. A sinvastina não altera esse perfil e previne a expressão de fatores inflamatórios como RORC?t e NALP3 inflamassomas. CONCLUSÕES: Em conjunto, os resultados sugerem um desequilíbrio dos mecanismos regulatórios que poderiam contribuir com a cronicidade e o perfil inflamatório na UCI. As estatinas apresentam maior efeito antiinflamatório que pró-inflamatório, sugerindo ter potencial clínico para o tratamento de doenças crônicas como a UCI. / INTRODUCTION: Chronic Idiopathic Urticaria (CIU) is a disease triggered by degranulation of basophils and mast cells with consequent histamine release and the CIU immunological profile is not well established. Statins, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, also display a broad immunomodulatory property. Statins have been studied in several chronic inflammatory diseases, including autoimmune disorders, but there are no evidences in CIU disease. OBJECTIVES: The aim of this study was to verify the effect of statins the immune response, and the expression of genes related to regulatory and inflammatory response focusing in CIU patients and healthy controls (HC). METHODS: Lymphoproliferative response to mitogens or recall antigens of 22 patients with CIU and 41 HC with statins (0,25-25µM) was analyzed by timidine incorporation after 3 or 6 days of cell cultures. Cell cycle progression and apoptosis were assessed by bromodeoxyiridine (BrDU) incorporation to DNA upon PHA or PWM stimulus by flow cytometry. Cytokines secretion was measured by ELISA and mRNA of regulatory and proinflammatory genes were analyzed by quantitative real-time PCR. RESULTS: The results showed that high concentrations of statins can inhibit the mitogenic capacity of T and B cells of HC or CIU patients. The inhibition of cell proliferation mediated by statins was due to blockage in the initial phase of the cell cycle (G0/1), which prevented progress to cycle phases (S and G2/M). The decreased proliferative response in response to PHA mediated by statin resulted in a significant inhibition of IFN-?, IL-10, IL-17A and IL-5 secretion levels. Statin effect in response to LPS showed inhibition of TNF-? and MIP-1? secretion by cells from HC, but did not influence the production by PBMC of CIU. It was necessary the pre-incubation of cells with drugs at high concentration (25µM) to verify the negative modulation of IL-6 and MIP1-? secretion in both groups, except for TNF-? in CIU. Simvastatin was able to exert more pronounced modulatory effect than lovastatin in cytokine production induced by LPS. Furthermore, CIU patients have a decreased expression of the enzyme IDO and increased of SOCS3 in PBMC, which were not modified by simvastatin, whereas prevented the upregulation of proinflammatory factor as RORC?t and NALP3 inflammasomes. CONCLUSIONS: Altogether, the results evidenced an imbalance of regulatory mechanisms that could contribute to chronic evolution and inflammatory profile in CIU. Statins exhibited more anti-inflammatory effects than proinflammatory, suggesting a potential clinical role for treatment in chronic diseases as CIU.
200

Resposta da púrpura trombocitopênica idiopática à esplenectomia tardia.

Bassitt, Rogerio Pastore 07 February 2002 (has links)
A púrpura trombocitopênica idiopática (PTI) é uma patologia adquirida que leva à redução da contagem de plaquetas, mediada por mecanismo imunológico. O tratamento inicial é a corticoterapia e, se caracterizada a falência ou dependência desta, a esplenectomia é a segunda opção. Autores recomendam que a esplenectomia seja realizada antes de se completarem 12 meses do diagnóstico, apesar de estudos sugerirem que a resposta após este período é semelhante. Neste estudo, pesquisaram-se a eficácia da esplenectomia tardia, as complicações da manutenção da terapia imunossupressora e as complicações hemorrágicas na população com esplenectomia tardia. Analisaram-se prontuários de 39 pacientes com idade de 4 a 64 anos (mediana de 27 anos) ao diagnóstico, submetidos à esplenectomia como procedimento terapêutico de PTI. Classificaram-se as respostas à esplenectomia, observadas na última visita, após 6 meses da cirurgia, em resposta completa (RC) (mais de 150.000 plaquetas/ l) parcial (RP) (de 50.000 a 150.000 plaquetas/ l) ou sem resposta (SR) (menos de 50.000 plaquetas/ l ou necessidade de medicação para controle da PTI). No período anterior à esplenectomia, a prednisona causou efeitos colaterais em 18% dos pacientes. Uma paciente que utilizou azatioprina desenvolveu carcinoma ductal de mama. Outros efeitos colaterais da azatioprina, danazol, colchicina, levamisol e vincristina reverteram após a suspensão das drogas. Não houve mortalidade relacionada à PTI nem às esplenectomias, mas houve mais hemorragias graves (21%) no período pré-operatório. As esplenectomias foram realizadas após 1 a 174 meses (mediana 36 meses) do diagnóstico e a última visita ocorreu depois de 9 a 300 meses (mediana 25,5 meses) da cirurgia. As respostas finais à esplenectomia foram: 16 (44%) RC, 10 (28%) RP, 10 (28%) SR. A comparação entre as respostas dos pacientes que realizaram a esplenectomia antes e as dos que a realizaram após 36 meses não mostrou diferença significativa (p=0,687). A esplenectomia tardia tem eficácia, aferida pela soma das RC e RP, comparável à citada pela literatura. As medicações imunossupressoras produziram mais efeitos colaterais e ocorreram mais hemorragias graves do que as relatadas pela literatura. / Idiopathic thrombocytopenic purpura (ITP) is an acquired immunologic disorder associated with reduction of platelet count. The primary treatment is prednisone in the majority of cases, and if it fails or if there is a dependence of it, the splenectomy is performed. The surgery is usually indicated within 12 months after diagnosis because of presumed better results. Nevertheless, clinical studies suggest that splenectomy is effective when performed after this 12 months. In this study the hemorrhagic complications of ITP, the side effects of immunossupressive therapy during preoperative period and the efficacy and safety of the procedure were studied in a population with late splenectomy. Thirty nine patients were included with median age of 27 years (range 4 to 64 years) at the diagnosis of ITP. The response to splenectomy were classified as complete response (CR) (platelets counts above 150.000/ l), partial response (PR) (platelet counts of 50.000 to 150.000/ l), and no response (NR) (less than 50.000/ l or use of drugs to maintain platelet count). In the preoperative period, prednisone caused side effects in 18% of patients. One patient who received azathioprine had breast cancer. Other side effects of azathioprine, danazol, colchicin, levamisole and vincristine remitted after drugs withdrawal. The surgeries were performed after 1 to 174 months of diagnosis (median of 36 months). Of the 39 patients, 36 had assessment of response to splenectomy after 9 to 300 months: 16 patients had CR (44%), 10 PR (28%), and 10 NR (28%). The responses of the patients with period of diagnosis to splenectomy of 36 months or more were not different from the patients with this period of less than 36 months (p=0.687). During the preoperative period, 21% of patients had severe hemorrhagic complications of ITP, but there were no death caused by ITP or splenectomy. Although, the favorable response (sum of CR and PR) of late splenectomy was similar, there were more side effects of immunossupressive therapy and severe hemorrhagic complications than the reported in the literature. Splenectomy is a therapeutic option for immune thrombocytopenic purpura (ITP), usually recommend before 12 months after diagnosis. In this study, 39 patients were splenectomized 1 to 174 months (median of 36 months) after the hemorrages and more side effects of prednisone than reported in the literature, but there were death. The favorable responses of late splectomy were similar to the reported in the literature. the favorable responses of the group with period of ITP diagnosis to splenectomy of the 36 months or more were not different from the group with less than 36 months (p=0.687).

Page generated in 0.0608 seconds