No description available.

Physiological cross sectional area (PCSA) is used to compare force-producing capabilities of skeletal muscles. PCSA has been defined as the summation of the cross sectional area of the fiber bundles composing the muscle. As PCSA cannot be measured directly from a specimen, a formula requiring averaged muscle architectural parameters has traditionally been used. The purpose of this study was to develop a finite element method (FEM) to calculate PCSA of extensor carpi radialis longus (ECRL) and brevis (ECRB) directly from digitized fiber bundle data obtained throughout the volume of the muscle and to compare the PCSAs calculated using the FEM and formula methods. Differences were found between the FEM and formula method for both muscles. The FEM provides an approach that takes into account architectural variances while minimizing the need for averaged architectural parameters.

Physiological cross sectional area (PCSA) is used to compare force-producing capabilities of skeletal muscles. PCSA has been defined as the summation of the cross sectional area of the fiber bundles composing the muscle. As PCSA cannot be measured directly from a specimen, a formula requiring averaged muscle architectural parameters has traditionally been used. The purpose of this study was to develop a finite element method (FEM) to calculate PCSA of extensor carpi radialis longus (ECRL) and brevis (ECRB) directly from digitized fiber bundle data obtained throughout the volume of the muscle and to compare the PCSAs calculated using the FEM and formula methods. Differences were found between the FEM and formula method for both muscles. The FEM provides an approach that takes into account architectural variances while minimizing the need for averaged architectural parameters.

No description available.

Chez l’humain et le chien, certaines atteintes respiratoires peuvent mener à une augmentation de la pression artérielle pulmonaire (PAP) et à un remodelage des artères pulmonaires. Chez le chat domestique, de telles conséquences n’ont que rarement été rapportées. Dans ce mémoire de maîtrise, nous avons étudié l’impact des atteintes respiratoires sur l’hémodynamie et la structure des vaisseaux artériels pulmonaires chez felis catus domestica à l’aide de deux approches méthodologiques. La première s’intéressait au temps d’intervalles systoliques (STIs) mesurés à l’échocardiographie et leur corrélation avec l’estimation de la PAP. Dix-sept autres paramètres échocardiographiques chez 10 chats atteints de maladies respiratoires chroniques ont été comparés à ceux de 16 chats sains. Aucune différence significative n’a été démontrée entre les deux groupes pour l’ensemble des paramètres. Les STIs n’étaient pas corrélés à l’estimation de la PAP, limitant leur potentiel prédictif d’hypertension pulmonaire chez le chat. La deuxième approche visait à déterminer histologiquement l’incidence des désordres bronchiolaires (BD) sur le remodelage artériel pulmonaire, à l’aide de tissus pulmonaires provenant de 13 chats atteints à ceux de 13 chats témoins. La proportion de la paroi artérielle occupée par l’adventice était significativement plus élevée chez les chats BD que celle du groupe contrôle, chez qui l’intima et la média était significativement plus proéminente chez les artères de petit et moyen calibre, respectivement. Cet effet opposé s’est soldé par une épaisseur pariétale totale comparable entre les deux groupes. D’autres études seront nécessaires pour comprendre les mécanismes physiologiques sous-jacents aux changements histologiques observés lors de BD. / In humans and dogs, respiratory disorders can lead to increased pulmonary arterial pressure (PAP) and a remodeling of the pulmonary arteries. In domestic cats, such consequences have rarely been reported. In this master's thesis, we studied the impact of respiratory diseases on pulmonary hemodynamics and on pulmonary arterial morphometry in felis catus domestica using two methodological approaches Our first study focused on systolic time intervals (STIs) and their correlation with estimated PAP, upon which 17 other echocardiographic parameters were compared between 10 cats with chronic respiratory diseases and 16 healthy cats. No significant differences were observed between the two groups for any of the parameters that were measured. STIs did not correlate with estimated PAP, limiting their predictive potential of pulmonary hypertension in cats. The second study’s aim was to determine the histological impact of bronchiolar disorders (BD) on the remodeling of pulmonary arteries using pulmonary tissues from 13 affected cats compared to those of 13 control cats. The proportion of the arterial wall occupied by the adventitia was significantly higher in cats in with BD than that of the control group, of which the intima and media were significantly more prominent in small and medium caliber arteries, respectively. This opposite effect resulted in a comparably similar wall thickness between the two groups. Further studies will be needed to understand the physiological mechanisms underlying the histological changes observed in cats with BD.