Le développement des proportions métaphysaires chez les hominoïdes : croissance et influence de la locomotion

Dans le cadre de ce mémoire, les relations entre morphologie, locomotion et croissance chez les hominoïdes sont analysées sous l'angle des proportions métaphysaires et de leur acquisition. Plusieurs niveaux d'analyse — intermembre, supérieur et inférieur — sont abordés dans une perspective ontogénique. La masse corporelle et la direction des charges influencent la morphologie des surfaces articulaires et métaphysaires mais aussi leur développement. Les charges étant dépendantes du mode locomoteur et celui-ci se modifiant en fonction de l'âge, on tente de voir à quel(s) moment(s) les changements proportionnels ont lieu et pourquoi ils apparaissent. Des mesures linéaires ont été recueillies sur l'humérus, le radius, le fémur et le tibia sur un échantillon squelettique des espèces H. sapiens, P. troglodytes, G. gorilla et P. pygmaeus. À partir de ces mesures et du calcul de certains ratios, des comparaisons intra et interspécifiques ont été réalisées. Les différences les plus significatives entre les espèces se dévoilent au niveau intermembre et sont relatives aux différents pourcentages d'utilisation des membres supérieurs ou inférieurs. Au sein des espèces, les résultats révèlent une similarité dans les réactions des surfaces métaphysaires au niveau intermembre, supérieur et inférieur. Les changements proportionnels ont lieu entre les stades 0 et 1 pour H. sapiens (première marché indépendante), entre les stades 2 et 4 pour P. troglodytes (majorité du poids corporel soutenue par les membres inférieurs) et entre les stades 3 et 5 pour G. gorilla (taille adulte et quadrupédie très majoritaire). Pour P. pygmaeus aucun stade en particulier n'a été ciblé par les analyses et cela concorde avec l'homogénéité de ses modes de locomotion employés au cours de la vie. Les différences proportionnelles répondent à des changements locomoteurs majeurs. Australopithecus afarensis est intermédiaire entre H. sapiens et les grands singes pour de nombreuses comparaisons. Au niveau du genou, les plus jeunes individus A. afarensis ne montrent pas de morphologie bipède, similaire aux humains.

Évaluation biomécanique de la locomotion à la suite d'une arthroplastie de la hanche

Depuis les dernières années, la prévalence de personnes souffrant de dégénérescence des cartilages articulaires, communément appelée ostéoarthrite (OA), ne cesse d’augmenter. Les douleurs articulaires et les raideurs musculaires associées à cette pathologie mènent à des limitations des capacités fonctionnelles, à une perte de mobilité et d’autonomie affectant grandement la qualité de vie de ces personnes. Afin de soulager les personnes souffrant de cette pathologie, l’arthroplastie de la hanche est une procédure chirurgicale fréquemment utilisée. À la suite de cette chirurgie, une amélioration de la qualité de vie et une reprise des capacités fonctionnelles sont souvent observées. Cependant, comparativement à des sujets sains, la vitesse de marche est diminuée, une faiblesse des muscles abducteurs de la hanche est constatée et des mouvements compensatoires au niveau du tronc sont persistants. L’objectif de cette thèse est d’évaluer le patron locomoteur chez des patients qui subiront une arthroplastie de la hanche. Plus spécifiquement, les adaptations locomotrices pré et post-opératoires seront quantifiées dans le but d’apporter des modifications aux programmes de réhabilitation pour ainsi favoriser un patron locomoteur sans déficit. Afin de répondre à cet objectif, trois études distinctes ont été effectuées. Dans le cadre de la première étude, l’impact de l’implantation d’une prothèse totale de la hanche avec une tête fémorale de large diamètre et une prothèse de resurfaçage a été évalué par rapport aux sujets sains lors de la locomotion. Au cours de cette étude, le contrôle du tronc a été analysé en utilisant la distance entre le centre de masse corporel et le centre articulaire de la hanche opérée. Suite aux résultats obtenus, aucune différence majeure n’existe entre les deux types de prothèses en ce qui a trait au contrôle du tronc et ce, à un an post-opératoire. Lors de la deuxième étude, la symétrie des paramètres biomécaniques des membres inférieurs lors de la locomotion chez des patients ayant bénéficié de l’implantation d’une prothèse de la hanche a été caractérisée suite à un programme d’exercices péri-opératoires (pré et post-opératoire). Lors de cette étude, le programme d’exercices péri-opératoires était complémentaire au protocole de réadaptation du centre hospitalier. D’après les résultats obtenus lors de cette étude exploratoire, ce programme d’exercices péri-opératoires semble permettre d’améliorer la symétrie de la puissance et du travail musculaire au niveau de la hanche, du genou et de la cheville favorisant ainsi un patron de marche avec de minimes compensations. Finalement, dans le cadre de la troisième étude, l’approche prédictive et l’approche fonctionnelle, utilisées pour localiser le centre articulaire de la hanche, ont été comparées aux mesures radiographiques, chez des patients à la suite d’un remplacement articulaire de la hanche. À la suite de cette étude, les résultats démontrent que l’utilisation de l’approche fonctionnelle est plus appropriée chez des patients ayant bénéficié d’une arthroplastie de la hanche. En effet, cette approche individualisée est plus précise ce qui, par conséquent, permettra d’obtenir des résultats de plus grande qualité lors d’analyses biomécaniques de la locomotion.

L'importance du système noradrénergique aux niveaux thoracique et lombaire de la moelle épinière pour la locomotion du chat

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Eye-movements aid the control of locomotion

Eye-movements have long been considered a problem when trying to understand the visual control of locomotion. They transform the retinal image from a simple expanding pattern of moving texture elements (pure optic flow), into a complex combination of translation and rotation components (retinal flow). In this article we investigate whether there are measurable advantages to having an active free gaze, over a static gaze or tracking gaze, when steering along a winding path. We also examine patterns of free gaze behavior to determine preferred gaze strategies during active locomotion. Participants were asked to steer along a computer-simulated textured roadway with free gaze, fixed gaze, or gaze tracking the center of the roadway. Deviation of position from the center of the road was recorded along with their point of gaze. It was found that visually tracking the middle of the road produced smaller steering errors than for fixed gaze. Participants performed best at the steering task when allowed to sample naturally from the road ahead with free gaze. There was some variation in the gaze strategies used, but sampling was predominantly of areas proximal to the center of the road. These results diverge from traditional models of flow analysis.

Techniques for image analysis of movement of juveniles of root-knot nematodes encumbered with Pasteuria penetrans spores

Root-knot nematodes (Meloidogyne spp.) are the most significant plant-parasitic nematodes that damage many crops all over the world. The free-living second stage juvenile (J2) is the infective stage that enters plants. The J2s move in the soil water films to reach the root zone. The bacterium Pasteuria penetrans is an obligate parasite of root-knot nematodes, is cosmopolitan, frequently encountered in many climates and environmental conditions and is considered promising for the control of Meloidogyne spp. The infection potential of P. penetrans to nematodes is well studied but not the attachment effects on the movement of root-knot nematode juveniles, image analysis techniques were used to characterize movement of individual juveniles with or without P. penetrans spores attached to their cuticles. Methods include the study of nematode locomotion based on (a) the centroid body point, (b) shape analysis and (c) image stack analysis. All methods proved that individual J2s without P. penetrans spores attached have a sinusoidal forward movement compared with those encumbered with spores. From these separate analytical studies of encumbered and unencumbered nematodes, it was possible to demonstrate how the presence of P. penetrans spores on a nematode body disrupted the normal movement of the nematode.

Head shape evolution in Tropidurinae lizards: does locomotion constrain diet?

Different components of complex integrated systems may be specialized for different functions, and thus the selective pressures acting on the system as a whole may be conflicting and can ultimately constrain organismal performance and evolution. The vertebrate cranial system is one of the most striking examples of a complex system with several possible functions, being associated to activities as different as locomotion, prey capture, display and defensive behaviours. Therefore, selective pressures on the cranial system as a whole are possibly complex and may be conflicting. The present study focuses on the influence of potentially conflicting selective pressures (diet vs. locomotion) on the evolution of head shape in Tropidurinae lizards. For example, the expected adaptations leading to flat heads and bodies in species living on vertical structures may conflict with the need for improved bite performance associated with the inclusion of hard or tough prey into the diet, a common phenomenon in Tropidurinae lizards. Body size and six variables describing head shape were quantified in preserved specimens of 23 species, and information on diet and substrate usage was obtained from the literature. No phylogenetic signal was observed in the morphological data at any branch length tested, suggesting adaptive evolution of head shape in Tropidurinae. This pattern was confirmed by both factor analysis and independent contrast analysis, which suggested adaptive co-variation between the head shape and the inclusion of hard prey into the diet. In contrast to our expectations, habitat use did not constrain or drive head shape evolution in the group.

Mechanical analysis of infant carrying in hominoids

In all higher nonhuman primates, species survival depends upon safe carrying of infants clinging to body hair of adults. In this work, measurements of mechanical properties of ape hair (gibbon, orangutan, and gorilla) are presented, focusing on constraints for safe infant carrying. Results of hair tensile properties are shown to be species-dependent. Analysis of the mechanics of the mounting position, typical of heavier infant carrying among African apes, shows that both clinging and friction are necessary to carry heavy infants. As a consequence, a required relationship between infant weight, hair-hair friction coefficient, and body angle exists. The hair-hair friction coefficient is measured using natural ape skin samples, and dependence on load and humidity is analyzed. Numerical evaluation of the equilibrium constraint is in agreement with the knuckle-walking quadruped position of African apes. Bipedality is clearly incompatible with the usual clinging and mounting pattern of infant carrying, requiring a revision of models of hominization in relation to the divergence between apes and hominins. These results suggest that safe carrying of heavy infants justify the emergence of biped form of locomotion. Ways to test this possibility are foreseen here.

Selecting appropriate bedding to reduce locomotion problems in broilers

Two experiments were carried out at the Poultry Sector of the School of Agrarian Sciences of the Federal University of Grande Dourados to evaluate the incidence of leg problems in broilers reared on two distinct types of bedding material: rice husks or wood shavings, both new and reused. In both trials, a randomized experimental design was applied in factorial arrangement (2 x 2 x 2) using two genetic strains (Cobb® or Ross®); two sexes (male or female), and two litter materials (rice husks or wood shavings). In each trial 1080 one day pullets were reared equally divided in the treatments. The birds were placed in 4.5 m² boxes at a density of 10 birds m-2. All birds were fed diets with equal nutritional density, and water was offered ad libitum. Feeds were divided in three phases: starter diet (1 - 21 days), grower diet (22 - 35 days), and finisher diet (36 - 45 days). on day 45, fifty birds were randomly selected in each experiment to evaluate flock leg problems. The following parameters were analyzed: gait score, incidence of valgus and varus disorder, footpad dermatitis, femoral degeneration, tibial dyschondroplasia, and spondylolisthesis. Ambient temperature during rearing and litter caking and moisture content were recorded in four boxes per treatment. The analytical hierarchy process was used to organize the data into specific criteria. Several criteria, related to the attributes that were determinant according to the statistical analysis, were chosen in order to provide the best input to the process. Results indicated that new wood-shavings bedding was the most appropriate bedding to prevent locomotion problems, followed by new rice husks, reused wood shavings, and reused rice husks. However, when leg problems were associated to sex and genetic strain, male Ross birds strain presented less problems when reared on new rice husks, followed by new wood shavings

Assessing locomotion deficiency in broiler chicken

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Analysis of spermiogenesis like a tool in the study of the triatomines of the Brasiliensis subcomplex

The specific identification and systematic of triatomines have been based fundamentally on morphological observations. These organisms are classified into complexes and specific subcomplexes, principally for morphological parameters and geographical disposition. The use of cytogenetic analyzes has been represented as a tool in systematic and taxonomy of triatomines. Thus, the present work, through the analysis of spermiogenesis, aims to characterize this stage of spermatogenesis in triatomines little studied, and especially to compare it among the species Triatoma lenti and T. sherlocki, to assist in the diagnosis of differentiation of these insects. The presence of the heteropyknotic corpuscle is shown as a diagnostic tool to differentiate T. sherlocki and T. lenti, since it is absent in T. lenti. The analysis of the spermiogenesis in T. sherlocki also allowed us to address morphological differences between elongating cells, which were relatively smaller and more filamentous when compared to T lenti. Furthermore, the flagellum was observed in all stages of cell differentiation and elongation. This structure, which helps in the locomotion of the sperm, is hardly observed in cytogenetic analysis, especially throughout spermiogenesis. Thus, although other comparative approaches should be taken, this paper allowed emphasizing the analysis of spermiogenesis as an important cytotaxonomic tool that assists in the differentiation of morphologically related species, such as T. lenti and T. sherlocki. © 2013 Académie des sciences.

Gait analysis in giant anteater (myrmecophaga tridactyla) with the use of a pressure-sensitive walkway

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Gait analysis in dogs with pelvic fractures treated conservatively using a pressure-sensing walkway

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Molecular analysis of cell surface $\beta$1,4-galactosyltransferase function during lamellipodal formation, cell polarization, and cell migration

The rate and direction of fibroblast locomotion is regulated by the formation of lamellipodia. In turn, lamellipodal formation is modulated in part by adhesion of that region of the cell from which the lamellipodia will extend or orginate. Cell surface $\beta$1,4-galactosyltransferase (GalTase) is one molecule that has been demonstrated to mediate cellular interactions with extracellular matrices. In the case of fibroblasts, GalTase must be associated with the actin cytoskeleton in order to mediate cellular adhesion to laminin. The object of this study was to determine how altering the quantity of GalTase capable of associating with the cytoskeleton impacts cell motility. Stably transfected cell lines were generated that have increased or decreased levels of surface GalTase relative to its cytoskeleton-binding sites. Biochemical analyses of these cells reveals that there is a limited number of sites on the cytoskeleton with which GalTase can interact. Altering the ratio of GalTase to its cytoskeleton binding sites does not affect the cells' abilities to spread, nor does it affect the localization of cytoskeletally-bound GalTase. It does, however, appear to interfere with stress fiber bundling. Cells with altered GalTase:cytoskeleton ratios change their polarity of laminin more frequently, as compared to controls. Therefore, the ectopic expression of GalTase cytoplasmic domains impairs a cell's ability to control the placement of lamellipodia. Cells were then tested for their ability to respond to a directional stimulus, a gradient of platelet-derived growth factor (PDGF). It was found that the ability of a cell to polarize in response to a gradient of PDGF is directly proportional to the quantity of GalTase associated with its cytoskeleton. Finally, the rate of unidirectional cell migration on laminin was found to be directly dependent upon surface GalTase expression and is inversely related to the ability of surface GalTase to interact with the cytoskeleton. It is therefore proposed that cytoskeletal assembly and lamellipodal formation can be regulated by the altering the ratio of cytoplasmic domains for specific matrix receptors, such as GalTase, relative to their cytoskeleton-binding sites. ^

Analysis of behavioral changes in dairy cows associated with claw horn lesions

Detecting lame cows is important in improving animal welfare. Automated tools are potentially useful to enable identification and monitoring of lame cows. The goals of this study were to evaluate the suitability of various physiological and behavioral parameters to automatically detect lameness in dairy cows housed in a cubicle barn. Lame cows suffering from a claw horn lesion (sole ulcer or white line disease) of one claw of the same hind limb (n=32; group L) and 10 nonlame healthy cows (group C) were included in this study. Lying and standing behavior at night by tridimensional accelerometers, weight distribution between hind limbs by the 4-scale weighing platform, feeding behavior at night by the nose band sensor, and heart activity by the Polar device (Polar Electro Oy, Kempele, Finland) were assessed. Either the entire data set or parts of the data collected over a 48-h period were used for statistical analysis, depending upon the parameter in question. The standing time at night over 12 h and the limb weight ratio (LWR) were significantly higher in group C as compared with group L, whereas the lying time at night over 12 h, the mean limb difference (△weight), and the standard deviation (SD) of the weight applied on the limb taking less weight were significantly lower in group C as compared with group L. No significant difference was noted between the groups for the parameters of heart activity and feeding behavior at night. The locomotion score of cows in group L was positively correlated with the lying time and △weight, whereas it was negatively correlated with LWR and SD. The highest sensitivity (0.97) for lameness detection was found for the parameter SD [specificity of 0.80 and an area under the curve (AUC) of 0.84]. The highest specificity (0.90) for lameness detection was present for Δweight (sensitivity=0.78; AUC=0.88) and LWR (sensitivity=0.81; AUC=0.87). The model considering the data of SD together with lying time at night was the best predictor of cows being lame, accounting for 40% of the variation in the likelihood of a cow being lame (sensitivity=0.94; specificity=0.80; AUC=0.86). In conclusion, the data derived from the 4-scale-weighing platform, either alone or combined with the lying time at night over 12 h, represent the most valuable parameters for automated identification of lame cows suffering from a claw horn lesion of one individual hind limb.

Analysis and 2D Simulation of a Hexapod Robot Leg for Remote Exploration

A walking machine is a wheeled rover alternative, well suited for work in an unstructured environment and specially in abrupt terrain. They have some drawback like speed and power consumption, but they can achieve complex movements and protrude very little the environment they are working on. The locomotion system is determined by the terrain conditions and, in our case, this legged design has been chosen based in a working area like Rio Tinto in the South of Spain, which is a river area with abrupt terrain. A walking robot with so many degrees of freedom can be a challenge when dealing with the analysis and simulations of the legs. This paper shows how to deal with the kinematical analysis of the equations of a hexapod robot based on a design developed by the Center of Astrobiology INTA-CSIC following the classical formulation of equations