798 resultados para Muscles squelettiques


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Slaughtering of eels should be done not only under animal welfare aspects but as well under consumer protection and economical aspects with respect to technical feasibility. Methods must be practicable for enterprises slaughtering quantities of several kilograms up to several tons per day. Most methods applied up to now in whole Europe were (are) not in accordance with animal welfare mainly due to lacking prescriptions and alternative methods. The great number of experiments carried out within the frame of this project demonstrates the difficulties to combine optimal welfare demands with economical and technical fesibility aspects in one method. Measurements of EEG (electroencephalogram) and ECG (electrocardiogram) have shown that the method laid down in the german legislation does not perfectly stun all eels. This method was improved by applying a „prestun“ with 220 V for 1sec., followed by a 5 min phase at 45 V to prolongue the time of unconsciousness after the stun. Inflating nitrogen gas into the stunning bath additionally causes asphyxia during the stun. By this method 93% of the eels were stunned or even killed. Applying 220 V for bigger batches of eels (~400 kg) will cause big problems with the energy supply. Therefore this method is restricted to batches of 20 - 50 kg. The method laid down in the german legislation probably can be improved. Eels were stunned successfully without water, avoiding the problems of regional differences in the conductivity of the water. Other types of current and other frequencies and a combination of both should be tested as well as alternative electrode geometries also with respect to blood spots which occasionally occurred in the muscles preferably of bigger eels (>800 g). For the time being the method laid down in the german legislation is a reasonable compromise and under animal welfare aspects represents a considerable improvement.

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The molecular inputs necessary for cell behavior are vital to our understanding of development and disease. Proper cell behavior is necessary for processes ranging from creating one’s face (neural crest migration) to spreading cancer from one tissue to another (invasive metastatic cancers). Identifying the genes and tissues involved in cell behavior not only increases our understanding of biology but also has the potential to create targeted therapies in diseases hallmarked by aberrant cell behavior.

A well-characterized model system is key to determining the molecular and spatial inputs necessary for cell behavior. In this work I present the C. elegans uterine seam cell (utse) as an ideal model for studying cell outgrowth and shape change. The utse is an H-shaped cell within the hermaphrodite uterus that functions in attaching the uterus to the body wall. Over L4 larval stage, the utse grows bidirectionally along the anterior-posterior axis, changing from an ellipsoidal shape to an elongated H-shape. Spatially, the utse requires the presence of the uterine toroid cells, sex muscles, and the anchor cell nucleus in order to properly grow outward. Several gene families are involved in utse development, including Trio, Nav, Rab GTPases, Arp2/3, as well as 54 other genes found from a candidate RNAi screen. The utse can be used as a model system for studying metastatic cancer. Meprin proteases are involved in promoting invasiveness of metastatic cancers and the meprin-likw genes nas-21, nas-22, and toh-1 act similarly within the utse. Studying nas-21 activity has also led to the discovery of novel upstream inhibitors and activators as well as targets of nas-21, some of which have been characterized to affect meprin activity. This illustrates that the utse can be used as an in vivo model for learning more about meprins, as well as various other proteins involved in metastasis.

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A study of human eye movements was made in order to elucidate the nature of the control mechanism in the binocular oculomotor system.

We first examined spontaneous eye movements during monocular and binocular fixation in order to determine the corrective roles of flicks and drifts. It was found that both types of motion correct fixational errors, although flicks are somewhat more active in this respect. Vergence error is a stimulus for correction by drifts but not by flicks, while binocular vertical discrepancy of the visual axes does not trigger corrective movements.

Second, we investigated the non-linearities of the oculomotor system by examining the eye movement responses to point targets moving in two dimensions in a subjectively unpredictable manner. Such motions consisted of hand-limited Gaussian random motion and also of the sum of several non-integrally related sinusoids. We found that there is no direct relationship between the phase and the gain of the oculomotor system. Delay of eye movements relative to target motion is determined by the necessity of generating a minimum afferent (input) signal at the retina in order to trigger corrective eye movements. The amplitude of the response is a function of the biological constraints of the efferent (output) portion of the system: for target motions of narrow bandwidth, the system responds preferentially to the highest frequency; for large bandwidth motions, the system distributes the available energy equally over all frequencies. Third, the power spectra of spontaneous eye movements were compared with the spectra of tracking eye movements for Gaussian random target motions of varying bandwidths. It was found that there is essentially no difference among the various curves. The oculomotor system tracks a target, not by increasing the mean rate of impulses along the motoneurons of the extra-ocular muscles, but rather by coordinating those spontaneous impulses which propagate along the motoneurons during stationary fixation. Thus, the system operates at full output at all times.

Fourth, we examined the relative magnitude and phase of motions of the left and the right visual axes during monocular and binocular viewing. We found that the two visual axes move vertically in perfect synchronization at all frequencies for any viewing condition. This is not true for horizontal motions: the amount of vergence noise is highest for stationary fixation and diminishes for tracking tasks as the bandwidth of the target motion increases. Furthermore, movements of the occluded eye are larger than those of the seeing eye in monocular viewing. This effect is more pronounced for horizontal motions, for stationary fixation, and for lower frequencies.

Finally, we have related our findings to previously known facts about the pertinent nerve pathways in order to postulate a model for the neurological binocular control of the visual axes.

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Este estudo teve como objetivo verificar, através de uma revisão sistemática de ensaios clínicos aleatorizados, os benefícios da estimulação elétrica funcional endovaginal ou dos tratamentos conservadores às pacientes com incontinência urinária de esforço, e demonstrar qual modalidade de tratamento conservador apresenta melhores resultados na terapêutica dessas mulheres: a estimulação elétrica funcional endovaginal, em comparação com os cones vaginais ou a realização de exercícios perineais. Para tanto, foram realizadas buscas nas principais bases de dados científicos, por estudos que atendessem a pergunta da pesquisa, tipo de intervenção e tipo de participantes selecionados. Destes, foram selecionados 7 estudos que foram submetidos à análise dos revisores, que avaliaram os seguintes desfechos: episódios de perda urinária, quantificação das perdas urinárias através do pad-test, força da musculatura perineal, qualidade de vida, volume residual, capacidade cistométrica máxima, melhora dos sintomas, satisfação e cura. Todas as terapias pesquisadas apresentaram melhora dos sintomas da incontinência urinária de esforço; no entanto, segundo os desfechos avaliados, apresentaram diferença no resultado comparativo. Quanto às perdas urinárias, ao pad-test e à força da musculatura perineal, a realização dos exercícios pélvicos obteve os melhores resultados. Já a terapia por estimulação elétrica endovaginal e a terapia com os cones apresentaram resultados semelhantes, não sendo encontrada diferença significativa em nenhum dos desfechos analisados. De acordo com os achados obtidos nesta revisão sistemática, entendemos que o tratamento pela estimulação elétrica traz benefícios às pacientes com incontinência urinária de esforço. Os exercícios pélvicos demonstraram ser a terapia que reduz mais significativamente os sintomas ocasionados por esta condição

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The dynamic interaction of limb segments during movements that involve multiple joints creates torques in one joint due to motion about another. Evidence shows that such interaction torques are taken into account during the planning or control of movement in humans. Two alternative hypotheses could explain the compensation of these dynamic torques. One involves the use of internal models to centrally compute predicted interaction torques and their explicit compensation through anticipatory adjustment of descending motor commands. The alternative, based on the equilibrium-point hypothesis, claims that descending signals can be simple and related to the desired movement kinematics only, while spinal feedback mechanisms are responsible for the appropriate creation and coordination of dynamic muscle forces. Partial supporting evidence exists in each case. However, until now no model has explicitly shown, in the case of the second hypothesis, whether peripheral feedback is really sufficient on its own for coordinating the motion of several joints while at the same time accommodating intersegmental interaction torques. Here we propose a minimal computational model to examine this question. Using a biomechanics simulation of a two-joint arm controlled by spinal neural circuitry, we show for the first time that it is indeed possible for the neuromusculoskeletal system to transform simple descending control signals into muscle activation patterns that accommodate interaction forces depending on their direction and magnitude. This is achieved without the aid of any central predictive signal. Even though the model makes various simplifications and abstractions compared to the complexities involved in the control of human arm movements, the finding lends plausibility to the hypothesis that some multijoint movements can in principle be controlled even in the absence of internal models of intersegmental dynamics or learned compensatory motor signals.

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In this study we employed a dynamic recurrent neural network (DRNN) in a novel fashion to reveal characteristics of control modules underlying the generation of muscle activations when drawing figures with the outstretched arm. We asked healthy human subjects to perform four different figure-eight movements in each of two workspaces (frontal plane and sagittal plane). We then trained a DRNN to predict the movement of the wrist from information in the EMG signals from seven different muscles. We trained different instances of the same network on a single movement direction, on all four movement directions in a single movement plane, or on all eight possible movement patterns and looked at the ability of the DRNN to generalize and predict movements for trials that were not included in the training set. Within a single movement plane, a DRNN trained on one movement direction was not able to predict movements of the hand for trials in the other three directions, but a DRNN trained simultaneously on all four movement directions could generalize across movement directions within the same plane. Similarly, the DRNN was able to reproduce the kinematics of the hand for both movement planes, but only if it was trained on examples performed in each one. As we will discuss, these results indicate that there are important dynamical constraints on the mapping of EMG to hand movement that depend on both the time sequence of the movement and on the anatomical constraints of the musculoskeletal system. In a second step, we injected EMG signals constructed from different synergies derived by the PCA in order to identify the mechanical significance of each of these components. From these results, one can surmise that discrete-rhythmic movements may be constructed from three different fundamental modules, one regulating the co-activation of all muscles over the time span of the movement and two others elliciting patterns of reciprocal activation operating in orthogonal directions.

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A central question in Neuroscience is that of how the nervous system generates the spatiotemporal commands needed to realize complex gestures, such as handwriting. A key postulate is that the central nervous system (CNS) builds up complex movements from a set of simpler motor primitives or control modules. In this study we examined the control modules underlying the generation of muscle activations when performing different types of movement: discrete, point-to-point movements in eight different directions and continuous figure-eight movements in both the normal, upright orientation and rotated 90 degrees. To test for the effects of biomechanical constraints, movements were performed in the frontal-parallel or sagittal planes, corresponding to two different nominal flexion/abduction postures of the shoulder. In all cases we measured limb kinematics and surface electromyographic activity (EMB) signals for seven different muscles acting around the shoulder. We first performed principal component analysis (PCA) of the EMG signals on a movement-by-movement basis. We found a surprisingly consistent pattern of muscle groupings across movement types and movement planes, although we could detect systematic differences between the PCs derived from movements performed in each sholder posture and between the principal components associated with the different orientations of the figure. Unexpectedly we found no systematic differences between the figute eights and the point-to-point movements. The first three principal components could be associated with a general co-contraction of all seven muscles plus two patterns of reciprocal activatoin. From these results, we surmise that both "discrete-rhythmic movements" such as the figure eight, and discrete point-to-point movement may be constructed from three different fundamental modules, one regulating the impedance of the limb over the time span of the movement and two others operating to generate movement, one aligned with the vertical and the other aligned with the horizontal.

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A ação inibitória dos organofosforados sobre as esterases, por ser específica, pode ser empregada como um eficiente biomarcador da exposição de seres vivos aos organofosforados. A inibição da acetilcolinesterase (AChE; EC 3.1.1.7) provoca acúmulo do neurotransmissor acetilcolina nas fendas sinápticas colinérgicas, o que pode resultar na morte do indivíduo. Outra atividade também afetada por organofosforados é a da enzima carboxilesterase (CarbE; EC 3.1.1.1). CarbE estão envolvidas na fase I da biotransformação de xenobióticos e atuam como captadoras (scavengers) de organofosfatos, incluindo os formados pela biotransformação dos organofosforados. As CarbE estudadas até hoje se ligam com maior velocidade aos organofosfatos do que as colinesterases. Por isto se admite que CarbE possam diminuir, por captação estequiométrica, a ligação tóxica de moléculas de organofosfatos às acetilcolinesterases das sinapses colinérgicas e das placas motoras dos músculos. Experimentos realizados em nosso laboratório mostraram que a atividade da CarbE está aproximadamente 50% menor no soro e no fígado de pacus submetidos à hipoxia. Por causa disso, em razão de uma possível diminuição da capacidade captadora da CarbE, decidimos verificar se o pacu em hipoxia seria mais sensível aos agrotóxicos organofosforados. Para este propósito foram colocados seis pacus divididos em dois tanques. No primeiro tanque, os animais foram submetidos a 24 horas de hipoxia seguidos por mais 4 horas de exposição ao organofosforado metilparation em duas concentrações diferentes (0,02 ou 0,01 mg / L). No segundo tanque os animais permaneceram em normoxia durante o mesmo período de 24 horas e depois foram expostos ao metilparation como no primeiro tanque. As atividades da AChE ensaiada com acetiltiocolina, a da butirilcolinesterase (BChE) ensaiada com butiriltiocolina e a da CarbE ensaiada com p-nitrofenilacetato foram avaliadas no soro, fígado, cérebro, músculo e coração dos pacus. Houve redução de aproximadamente 35% da atividade de CarbE no soro dos pacus submetidos a 24 horas de hipoxia. Uma queda de 85% na atividade de CarbE do soro foi observada nos animais que sofreram hipoxia e subsequente exposição a 0,02 mg de metilparation por litro. Com metilparation a 0,01 mg/L a diminuição observada foi de 48,2%. No músculo dos pacus expostos a 0,02 mg/L, as atividades de AChE e BChE cairam pela metade quando os mesmos foram submetidos à hipoxia quando comparados a animais que permaneceram em normoxia. Nos diversos tecidos dos pacus expostos a 0,01 mg/L de metilparation não observamos diferenças significativas nas atividades de AChE, BChE ou CarbE. Concluímos que a duplicação da concentração de metilparation de 0,01 para 0,02 mg/L levou à atividade residual de CarbE do soro de 51,8% para 15%. A ausência de mudanças nas atividades das esterases dos tecidos de animais expostos a 0,01 mg/L entre os grupos hipoxia e normoxia deve ter ocorrido porque a concentração de organofosforado não foi suficiente para superar a primeira barreira de proteção das esterases séricas e atingir os tecidos. Mas, no experimento com 0,02 mg/L de metilparation, as inibições de AChE e de BChE no músculo dos animais em hipoxia podem ser explicadas pela diminuição da atividade de CarbE do soro dos pacus.

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Background: Limited information is available about predictors of short-term outcomes in patients with exacerbation of chronic obstructive pulmonary disease (eCOPD) attending an emergency department (ED). Such information could help stratify these patients and guide medical decision-making. The aim of this study was to develop a clinical prediction rule for short-term mortality during hospital admission or within a week after the index ED visit. Methods: This was a prospective cohort study of patients with eCOPD attending the EDs of 16 participating hospitals. Recruitment started in June 2008 and ended in September 2010. Information on possible predictor variables was recorded during the time the patient was evaluated in the ED, at the time a decision was made to admit the patient to the hospital or discharge home, and during follow-up. Main short-term outcomes were death during hospital admission or within 1 week of discharge to home from the ED, as well as at death within 1 month of the index ED visit. Multivariate logistic regression models were developed in a derivation sample and validated in a validation sample. The score was compared with other published prediction rules for patients with stable COPD. Results: In total, 2,487 patients were included in the study. Predictors of death during hospital admission, or within 1 week of discharge to home from the ED were patient age, baseline dyspnea, previous need for long-term home oxygen therapy or non-invasive mechanical ventilation, altered mental status, and use of inspiratory accessory muscles or paradoxical breathing upon ED arrival (area under the curve (AUC) = 0.85). Addition of arterial blood gas parameters (oxygen and carbon dioxide partial pressures (PO2 and PCO2)) and pH) did not improve the model. The same variables were predictors of death at 1 month (AUC = 0.85). Compared with other commonly used tools for predicting the severity of COPD in stable patients, our rule was significantly better. Conclusions: Five clinical predictors easily available in the ED, and also in the primary care setting, can be used to create a simple and easily obtained score that allows clinicians to stratify patients with eCOPD upon ED arrival and guide the medical decision-making process.

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The aim of this study was to evaluate the normalized response speed (Vrn) of the knee musculature (flexor and extensor) in high competitive level volleyball players using tensiomyography (TMG) and to analyze the muscular response of the vastus medialis (VM), rectus femoris (RF), vastus lateralis (VL), and biceps femoris (BF) in accordance with the specific position they play in their teams. One hundred and sixty-six players (83 women and 83 men) were evaluated. They belonged to eight teams in the Spanish women's superleague and eight in the Spanish men's superleague. The use of Vrn allows avoiding possible sample imbalances due to anatomical and functional differences and demands. We found differences between Vrn in each of the muscles responsible for extension (VM, RF, and VL) and flexion (BF) regardless of the sex. Normalized response speed differences seem to be larger in setters, liberos and outside players compared to middle blockers and larger in males when compared to females. These results of Vrn might respond to the differences in the physical and technical demands of each specific position, showing an improved balance response of the knee extensor and flexor musculature in male professional volleyball players.

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O litoral centro-sul do estado de Santa Catarina representa a mais importante área de concentração reprodutiva das baleias-franca-austral, Eubalaena australis, no Brasil. O objetivo deste estudo é caracterizar o padrão comportamental dos pares fêmea-filhote que migram para essas áreas ao longo de 10 temporadas reprodutivas (2003 a 2012). Observações realizadas em pontos fixos foram conduzidas de Julho a Novembro, entre 2003 e 2012, de seis a sete vezes por semana, entre as 6:00h e 17:00h. Os dados foram coletados com auxilio de binóculos Pentax 12x55 mm, bússola, relógio digital, e registrados em fichas de campo padronizadas. Os estados comportamentais (natação, descanso e ativo) foram registrados em intervalos de cinco minutos e a frequência de eventos registrada em cada intervalo de cinco minutos. Natação foi o estado comportamental que prevaleceu tanto para fêmeas e filhotes, seguido de descanso e ativo para as fêmeas e seguido de ativo e descanso para os filhotes. A natação e o descanso são importantes para as fêmeas pois exigem menos energia, já que precisam usá-la para atividades das quais a sobrevivência da espécie depende, como parir, amamentar e cuidar dos filhotes. Para os filhotes, o comportamento ativo é mais importante para o seu desenvolvimento motor e preparação para o processo migratório. Os eventos mais expressados por ambos fêmea e filhote foram exposições indefinidas, estas sendo duas vezes maior para os filhotes. Os filhotes apresentaram comportamentos aéreos em taxas maiores do que as fêmeas, o que denota a importância de tais comportamentos no auxílio ao desenvolvimento da coordenação e na aptidão motora e no fortalecimento da musculatura, melhorando a resistência para a migração. A taxa de ocorrência de eventos aéreos para as fêmeas foi geralmente mais baixa, provavelmente na tentativa de desencorajar os comportamentos ativos realizados pelos filhotes. Esses resultados reforçam a importância da área de estudo como área reprodutiva para a espécie. O número de baleias-franca está crescendo na área, bem como o potencial conflito com atividades humanas. Entender os padrões comportamentais dos pares fêmea-filhote de baleias-franca-austral no litoral de Santa Catarina podem servir como valiosas ferramentas para a elaboração de planos de manejo, contribuindo para a conservação da espécie no litoral brasileiro

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A incontinência urinária gera implicações negativas nos âmbitos emocional, social e econômico tanto para o indivíduo incontinente, como para seus cuidadores. A terapia comportamental é uma das abordagens não-invasivas para a incontinência urinária. A terapia comportamental é realizada durante as consultas de enfermagem e a atuação do enfermeiro consiste na aplicação de um protocolo de orientações sobre hábitos de vida, medidas de controle da micção, treinamento para realização do diário miccional, treinamento de exercícios perineais e avaliação da resposta da paciente à terapia. O estudo tem como base teórica a Teoria do autocuidado de Dorothea Elisabeth Orem, pois a terapia comportamental visa instrumentalizar o indivíduo a realizar práticas de autocuidado a partir do protocolo de atendimento do ambulatório. O objetivo da pesquisa é avaliar a efetividade da terapia comportamental aplicada pelo enfermeiro para o controle miccional e melhora da qualidade de vida da mulher idosa. Trata-se de um ensaio clínico não-controlado.40 Foram incluídas no estudo mulheres acima de 60 anos que participam do Ambulatório do Núcleo de Atenção ao Idoso com a queixa clínica de perda involuntária de urina encaminhadas para o ambulatório de urogeriatria. A população estudada foi composta por 13 participantes. Os dados da pesquisa foram coletados a partir dos instrumentos de avaliação do ambulatório de urogeriatria que foram arquivados nos prontuários das pacientes: o diário miccional, avaliação de enfermagem na terapia comportamental e o questionário sobre qualidade de vida em mulheres com incontinência urinária chamado de Kings Health Questionnaire. Estes instrumentos foram aplicados antes e depois da terapia comportamental. Foram colhidos dados das pacientes acompanhadas no ambulatório durante o período de abril de 2011 a junho de 2012. Os resultados foram que após a terapia comportamental todas as idosas responderam que ingerem líquidos no período diurno, 92,30% das idosas responderam que estabeleceram um ritmo miccional de 2/2 horas ou de 3/3 horas. Sobre o parâmetro miccional perda de urina ao final da terapia comportamental 75% das idosas apresentaram ausência de perda de urina. Além disso, após a terapia comportamental nenhuma das pacientes teve perda de urina durante a realização dos exercícios e 92,30% apresentaram contração eficiente dos músculos perineais. Deste modo, esta pesquisa demonstrou que as idosas que participaram da terapia comportamental obtiveram melhora do controle urinário e da qualidade de vida. A terapia é um sistema que sofre retroalimentação à medida que o paciente adere às práticas de autocuidado e o enfermeiro reforça as orientações a fim de atingir o objetivo maior que é a sensação de bem estar. A teoria de Dorothea Orem se adequou bem ao estudo, pois a terapia comportamental permitiu aos idosos a assumirem responsabilidade com o seu corpo e se empenharem efetivamente para melhorar a sua condição de saúde e qualidade de vida.

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Muscular injection has become one of the direct methods for transferring foreign DNA into organisms. The technique has been recently introduced in the development of vaccines and gene therapy. Vaccine development, in particular, would be desirable in managing viral diseases in farmed fish. In this study, the technique was performed on seabass (Lates calcarifer) and was found that the foreign gene could be transferred successfully through injection into the muscles.