Effets de l'application de charges aux membres inférieurs sur le patron de marche des personnes hémiparétiques chroniques

Placer une charge au niveau du membre inférieur est une approche sans fondement scientifique, utilisée par les cliniciens, pour renforcer certains muscles clés de la marche. Cette étude a déterminé les modifications du patron de marche lors de l’ajout d’une charge à la cheville parétique ou non parétique chez des personnes ayant une hémiparésie suite à un accident vasculaire cérébral et a comparé les résultats à ceux d’un groupe témoin. Il est supposé qu’une charge placée à la jambe parétique/non dominante (charge ipsilatérale) augmenterait les efforts (moments et puissance) à la hanche parétique/non dominante lors de l’oscillation et qu’une charge placée controlatéralement augmenterait les efforts lors de la phase d’appui principalement pour les abducteurs de hanche stabilisant le bassin dans le plan frontal. La marche avec et sans charge de cinq individus hémiparétiques chroniques et 5 personnes en santé a été analysée en laboratoire par l’enregistrement des forces de réaction du sol et des mouvements des membres inférieurs. Ces informations ont permis de calculer les paramètres temps-distance, les angles à la hanche parétique/non dominante et au tronc, les moments nets, les puissances et le travail mécanique à la hanche parétique/non dominante. Des tests statistiques non-paramétriques ont servi à déterminer l’effet de la condition, avec charge (ipsi- et controlatérale) ou sans charge et à comparer les résultats entre les deux groupes. L’ajout d’une charge n’a pas modifié la vitesse de marche des sujets. Les phases d’appui et d’oscillation étaient rendus plus symétriques par la charge, même si peu de différences apparaissaient dans le plan sagittal avec ou sans la charge. Dans le plan frontal, le moment abducteur de hanche des sujets hémiparétiques a diminué avec la charge controlatérale, tandis qu'il a augmenté chez les sujets en santé. L’utilisation d’une stratégie posturale ou dynamique au tronc pourrait expliquer la différence de l’effet de la charge sur le moment abducteur à la hanche. Au vu de ces résultats, il est nécessaire de poursuivre l’évaluation de cette approche de renforcement musculaire spécifique à la tâche avant d’en recommander son utilisation.

La force de réaction au sol verticale maximale comme témoin d'effets fonctionnels et structuraux chez des modèles canins d'arthrose : potentiel envers le développement thérapeutique

Les modèles animaux d’arthrose permettent d’évaluer le potentiel d’agents thérapeutiques en phase préclinique de développement. Le présent ouvrage tient compte du chien comme modèle d’arthrose naturelle (chez l’animal de compagnie) ou expérimentale (par sectionnement chirurgical du ligament croisé crânial). Au sein des expérimentations, la force de réaction au sol verticale maximale, mesurée lors de l’analyse cinétique de la locomotion, est proposée comme témoin d’effets fonctionnels et structuraux sur ces modèles d’arthrose. Sur un modèle canin d’arthrose naturelle, le seuil de changement minimal détectable a été déterminé. Les changements au dysfonctionnement locomoteur peuvent désormais être cernés en s’affranchissant de la marge d’erreur inhérente à la mesure de la force verticale maximale. Il en découle l’identification de répondants lors d’essais cliniques entrepris chez le chien arthrosique. Une analyse rétrospective a, par la suite, déterminé un taux de répondants de 62.8% et d’une taille d’effet de 0.7 pour des approches thérapeutiques actuellement proposées aux chiens arthrosiques. Cette analyse détermina également que la démonstration d’une réponse thérapeutique était favorisée en présence d’un fort dysfonctionnement locomoteur. Sur un modèle canin d’arthrose par sectionnement chirurgical du ligament croisé crânial, la force verticale maximale a démontré une relation inverse avec certains types de lésions arthrosiques évaluées à l’aide d’imagerie par résonance magnétique. Également, la sensibilité de la force verticale maximale a été mise en évidence envers la détection d’effets structuraux, au niveau de l’os sous-chondral, par un agent anti-résorptif (le tiludronate) sur ce même modèle. Les expérimentations en contexte d’arthrose naturelle canine permettent de valider davantage les résultats d’essais cliniques contrôlés utilisant la force verticale maximale comme critère d’efficacité fonctionnelle. Des évidences cliniques probantes nécessaires à la pratique d’une médecine basée sur des faits sont ainsi escomptées. En contexte d’arthrose expérimentale, la pertinence d’enregistrer le dysfonctionnement locomoteur est soulignée, puisque ce dernier est en lien avec l’état des structures. En effectuant l’analyse de la démarche, de pair avec l’évaluation des structures, il est escompté de pouvoir établir la répercussion de bénéfices structurels sur l’inconfort articulaire. Cet ouvrage suggère qu’une plateforme d’investigations précliniques, qui combine le modèle canin d’arthrose par sectionnement chirurgical du ligament croisé crânial à un essai clinique chez le chien arthrosique, soit un moyen de cerner des bénéfices structuraux ayant des impacts fonctionnels. Le potentiel inférentiel de ces modèles canins d’arthrose vers l’Homme serait ainsi favorisé en utilisant la force verticale maximale.

Properties of singular vectors using convective available potential energy as final time norm

We study the feasibility of using the singular vector technique to create initial condition perturbations for short-range ensemble prediction systems (SREPS) focussing on predictability of severe local storms and in particular deep convection. For this a new final time semi-norm based on the convective available potential energy (CAPE) is introduced. We compare singular vectors using the CAPE-norm with SVs using the more common total energy (TE) norm for a 2-week summer period in 2007, which includes a case of mesoscale extreme rainfall in the south west of Finland. The CAPE singular vectors perturb the CAPE field by increasing the specific humidity and temperature of the parcel and increase the lapse rate above the parcel in the lower troposphere consistent with physical considerations. The CAPE-SVs are situated in the lower troposphere. This in contrast to TE-SVs with short optimization times which predominantly remain in the high troposphere. By examining the time evolution of the CAPE singular values we observe that the convective event in the south west of Finland is clearly associated with high CAPE singular values.

Inexpensive footwear decreases joint loading in elderly women with knee osteoarthritis

Recent literature has highlighted that the flexibility of walking barefoot reduces overload in individuals with knee osteoarthritis (OA). As such, the aim of this study was to evaluate the effects of inexpensive, flexible, non-heeled footwear (Moleca (R)) as compared with a modern heeled shoes and walking barefoot on the knee adduction moment (KAM) during gait in elderly women with and without knee OA. The gait of 45 elderly women between 60 and 70 years of age was evaluated. Twenty-one had knee OR graded 2 or 3 according to Kellgren and Lawrence`s criteria, and 24 who had no OA comprised the control group (CG). The gait conditions were: barefoot, Moleca (R), and modern heeled shoes. Three-dimensional kinematics and ground reaction forces were measured to calculate KAM by inverse dynamics. For both groups, the Moleca (R) provided peak KAM and KAM impulse similar to barefoot walking. For the OA group, the Moleca (R) reduced KAM even more as compared to the barefoot condition during midstance. On the other hand, the modern heeled shoes increased this variable in both groups. Inexpensive, flexible, and non-heeled footwear provided loading on the knee joint similar to a barefoot gait and significant overload decreases in elderly women with and without knee OA, compared to modern heeled shoes. During midstance, the Moleca (R) also allowed greater reduction in the knee joint loads as compared to barefoot gait in elderly women with knee OA, with the further advantage of providing external foot protection during gait. (C) 2011 Elsevier B.V. All rights reserved.

Supressão do ruído de rolamento superficial utilizando a transformada Curvelet

Among the many types of noise observed in seismic land acquisition there is one produced by surface waves called Ground Roll that is a particular type of Rayleigh wave which characteristics are high amplitude, low frequency and low velocity (generating a cone with high dip). Ground roll contaminates the relevant signals and can mask the relevant information, carried by waves scattered in deeper regions of the geological layers. In this thesis, we will present a method that attenuates the ground roll. The technique consists in to decompose the seismogram in a basis of curvelet functions that are localized in time, in frequency, and also, incorporate an angular orientation. These characteristics allow to construct a curvelet filter that takes in consideration the localization of denoise in scales, times and angles in the seismogram. The method was tested with real data and the results were very good

Extração de DNA de materiais de arquivo e fontes escassas para utilização em reação de polimerização em cadeia (PCR)

Este trabalho visou a comparação de cinco métodos diferentes de extração de DNA de materiais de arquivo (tecidos incluídos em parafina, esfregaços de sangue periférico - corados e não corados com Leishman, lâminas com mielogramas, gotas de sangue em Guthrie Card) e de fontes escassas (células bucais, um e três bulbos capilares e 2 mL de urina), para que fossem avaliadas a facilidade de aplicação e a facilidade de amplificação deste DNA pela técnica da reação de polimerização em cadeia (PCR). Os métodos incluíram digestão por proteinase K, seguida ou não por purificação com fenol/clorofórmio; Chelex 100® (BioRad); Insta Gene® (BioRad) e fervura em água estéril. O DNA obtido foi testado para amplificação de três fragmentos gênicos: Brain-derived neutrophic factor (764 pb), Factor V Leiden (220 pb) e Abelson (106 pb). de acordo com o comprimento do fragmento gênico estudado, da fonte potencial de DNA e do método de extração utilizado, os resultados caracterizaram o melhor caminho para padronização de procedimentos técnicos a serem incluídos no manual de Procedimentos Operacionais Padrão do Laboratório de Biologia Molecular do Hemocentro - HC - Unesp - Botucatu.

Fatores de risco associados à infecção por Toxoplasma gondii em ovinos e caprinos no estado de Pernambuco

Objetivou-se com este estudo investigar a participação de Toxoplasma gondii em falhas reprodutivas em pequenos ruminantes de criatórios situados na Zona da Mata e no Agreste do Estado de Pernambuco e que apresentavam histórico de distúrbios reprodutivos. Foram selecionadas 12 propriedades das quais se coletaram amostras de 262 animais, sendo 167 caprinos e 95 ovinos. Realizou-se a pesquisa de anticorpos anti-Toxoplasma gondii, utilizando-se a técnica da Imunofluorescência Indireta (RIFI). Foram aplicados questionários investigativos nas propriedades visitadas para identificar os fatores de risco associados à infecção. em 100% das propriedades foram encontrados animais soropositivos. Para T. gondii, das 167 amostras de soro caprino analisadas, 31,7% foram positivas, enquanto que na espécie ovina, das 95 amostras, 16,9% foram positivas. Para a espécie ovina, não foram observadas associações significativas. Para os caprinos, houve associação significativa (p<0,05) para as variáveis: manejo intensivo (OR=2,40), exploração leiteira (OR=2,10), animais procedentes de outros estados (OR=7,89) e monta natural (OR=5,69). Conclui-se que a infecção pelo T. gondii encontra-se disseminada nos rebanhos de caprinos e ovinos estudados e que medidas sanitárias devem ser adotadas para controlar os fatores de risco identificados neste estudo.

Características cinemáticas, cinéticas e eletromiográficas do andar de adultos jovens com e sem suporte parcial de peso corporal

OBJETIVO: O objetivo deste estudo foi analisar as características cinemáticas, cinéticas e eletromiográficas do andar de adultos jovens em piso fixo sem colete e com suporte parcial de peso (SPP) de 0, 10, 20 e 30% do peso corporal. MÉTODO: Oito jovens com idade média de 22,2 anos foram filmados andando sobre uma passarela que continha uma plataforma de força na região central para registro das componentes da força de reação do solo. Marcadores refletivos foram posicionados nos principais pontos anatômicos dos membros inferiores para registro dos dados cinemáticos, e eletrodos de superfície foram afixados nos músculos tibial anterior e gastrocnêmio medial para registro da atividade elétrica muscular. RESULTADOS: Diferenças significantes entre as cinco condições experimentais foram constatadas nas variáveis espaço-temporal, nos ângulos máximos e mínimos da coxa, joelho e tornozelo e nas amplitudes das componentes horizontal ântero-posterior e vertical da força de reação do solo. de forma geral, as maiores mudanças ocorreram na condição de SPP de 30% do peso corporal. CONCLUSÃO: É importante considerar as compensações que ocorrem no padrão do andar com SPP no planejamento das intervenções terapêuticas. Ainda, para melhor definir a utilização dos sistemas de suspensão de peso na reabilitação, estudos futuros precisam ser realizados para verificar o comportamento do andar em populações com alteração de movimento em piso fixo.

Prevalência de Cryptosporidium sp. em cães de instituições da cidade de São Paulo

Objective Dogs play an important role as infection source of human cryptosporidiosis. The objective of the study was to determine the prevalence of Cryptosporidium sp. in dogs as well as to compare two techniques of fecal analysis.Methods Four-hundred and fifty canine fecal samples from the city of São Paulo were analyzed between 2003 and 2004. Fecal samples were randomly selected from dogs housed in a university veterinary hospital (group 1, n=200) and private kennels (group 2, n=250). The detection of Cryptosporidium was performed using modified Ziehl-Neelsen staining and Polymerase Chain Reaction (PCR) technique. Statistical analysis was performed using the two-tailed test of significance at 5% confidence interval (z critical=+/- 1.645).Results Only Cryptosporidium parvum oocysts were found the prevalences found by light microscopy examination and PCR techniques were 8.8% and 9.5%, respectively. Young animals showed a lower frequency (5.5%) compared to adults (10.1%). There was no statistically significant difference in Cryptosporidium prevalence between males and females.Conclusions the prevalence of C. parvum in the canine population studied was similar to that one found in the literature and affects equally males and females. The use of PCR allowed the detection of more positive cases than light microscopy.

Influence of ankle functional instability on the ankle electromyography during landing after volleyball blocking

The purpose of this study was to describe, interpret and compare the EMG activation patterns of ankle muscles - tibialis anterior (TA), peroneus longus (PL) and gastrocnemius lateralis (GL) - in volleyball players with and without ankle functional instability (FI) during landing after the blocking movement. Twenty-one players with FI (IG) and 19 controls (CG) were studied. The cycle of movement analyzed was the time period between 200 ms before and 200 ms after the time of impact determined by ground reaction forces. The variables were analyzed for two different phases: pre-landing (200 ms before impact) and post-landing (200 ms after impact). The RMS values and the timing of onset activity were calculated for the three studied muscles, in both periods and for both groups. The co-activation index for TA and PL, TA and GL were also calculated. Individuals with FI presented a lower RMS value pre-landing for PL (CG = 43.0 perpendicular to 22.0; IG = 26.2 perpendicular to 8.4, p < 0.05) and higher RMS value post-landing (CG = 47.5 perpendicular to 13.3; IG = 55.8 perpendicular to 21.6, p < 0.10). Besides that, in control group PL and GL activated first and simultaneously, and TA presented a later activation, while in subjects with FI all the three muscles activated simultaneously. There were no significant differences between groups for co-activation index. Thus, the rate of contraction between agonist and antagonist muscles is similar for subjects with and without FI but the activation individually was different. Volleyball players with functional instability of the ankle showed altered patterns of the muscles that play an important role in the stabilization of the foot-ankle complex during the performance of the blocking movement, to the detriment of the ligament complex, and this fact could explain the usual complaints in these subjects. (C) 2007 Elsevier Ltd. All rights reserved.

Desenvolvimento morfolôgico dos ovários em embriões e fetos bovinos da raça Nelore

The morphologic events related to the prenatal development of the ovaries in 81 Nelore breed embryos and fetuses gathered in a local slaughterhouse, with age range from 26 to 240 days following fecundation were studied. The age of fetuses was estimated from measures taken in the cranium-caudal direction. The sex was identified from macroscopic observations and using Polymerase Chain Reaction (PCR) technique. For histology the gonads were fixed in Bourn's fluid for 24 hours and 5 μm thick section's were stained with hematoxylin-eosin. Formation of gonadal ridge and presence of germinal cells were found within it at 29 and 34 days, respectively. Oogonia and primordial follicles, unlike the growing follicles, exhibited significant differences in diameter in the various periods studied. Positive correlation (P<0.05) was found between the diameter of oogonia and their nucleus as well as between primordial and growing follicles with their oocytes and respective nuclei. The gonad was fully formed at 40 days. Primordial follicles, in the growing stage, and antral follicles first appeared, approximately at 95, 140, and 180 days, respectively. Despite the onset and duration of oogenesis being similar to that of taurine breeds, folliculogenesis initiates at an early stages in the Nelore breed.

Age-related differences in time-limit performance and force platform-based balance measures during one-leg stance

Poor posture control has been associated with an increased risk of falls and mobility disability among older adults. This study was conducted to assess the test-retest reliability and sensitivity to group differences regarding the time-limit (TLimit) of one-leg standing and selected balance parameters obtained with a force platform in older and young adults. A secondary purpose was to assess the relationship between TLimit and these balance parameters. Twenty-eight healthy older adults (age: 69±5years) and thirty young adults (age: 21±4years) participated in this study. Two one-leg stance tasks were performed: (1) three trials of 30s maximum and (2) one TLimit trial. The following balance parameters were computed: center of pressure area, RMS sway amplitude, and mean velocity and mean frequency in both the anterio-posterior and medio-lateral directions. All balance parameters obtained with the force platform as well as the TLimit variable were sensitive to differences in balance performance between older and young adults. The test-retest reliability of these measures was found to be acceptable (ICC: 0.40-0.85), with better ICC scores observed for mean velocity and mean frequency in the older group. Pearson correlations coefficients (r) between balance parameters and TLimit ranged from -0.16 to -0.54. These results add to the current literature that can be used in the development of measurement tools for evaluating balance in older and young adults. © 2013 Elsevier Ltd.

Comportamento locomotor na doença de Parkinson: tarefas de subir e descer degraus

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito da duração do intervalo em saltos verticais: relações entre trabalho realizado e duração até a exaustão

Pós-graduação em Ciências da Motricidade - IBRC

Avaliação da força aplicada à articulação do ombro em cadeirantes durante a manobra de transferência

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)