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1.
Behav Pharmacol ; 32(4): 259-264, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-33595953

RESUMO

Serotonin plays a pivotal role in the initiation and modulation of locomotor behavior in the intact animal, as well as following spinal cord injury. Quipazine, a serotonin 2 receptor agonist, has been used successfully to initiate and restore motor behavior in rodents. Although evidence suggests that the effects of quipazine are spinally mediated, it is unclear whether intrathecal (IT) quipazine administration alone is enough to activate locomotor-like activity or whether additional stimulation is needed. Thus, the current study examined the effects of IT administration of quipazine in postnatal day 1 rats in two separate experiments. In experiment 1, quipazine (0.1, 0.3, or 1.0 mg/kg) was dissolved in saline and administered via IT injection to the thoracolumbar cord. There was no significant effect of drug on hindlimb alternating stepping. In experiment 2, quipazine (0.3 or 1.0 mg/kg) was dissolved in a polysorbate 80-saline solution (Tween 80) and administered via IT injection. Polysorbate 80 was used to disrupt the blood-brain barrier to facilitate absorption of quipazine. The injection was followed by tail pinch 5 minutes post-injection. A significant increase in the percentage of hindlimb alternating steps was found in subjects treated with 0.3 mg/kg quipazine, suggesting that IT quipazine when combined with sensory stimulation to the spinal cord, facilitates locomotor-like behavior. These findings indicate that dissolving the drug in polysorbate 80 rather than saline may heighten the effects of IT quipazine. Collectively, this study provides clarification on the role of quipazine in evoking spinally-mediated locomotor behavior.


Assuntos
Barreira Hematoencefálica/efeitos dos fármacos , Injeções Espinhais/métodos , Cinese , Atividade Motora/efeitos dos fármacos , Polissorbatos/farmacologia , Quipazina , Animais , Animais Recém-Nascidos , Disponibilidade Biológica , Cinese/efeitos dos fármacos , Cinese/fisiologia , Quipazina/administração & dosagem , Quipazina/farmacocinética , Ratos , Receptores 5-HT2 de Serotonina/metabolismo , Agonistas do Receptor 5-HT2 de Serotonina/administração & dosagem , Agonistas do Receptor 5-HT2 de Serotonina/farmacocinética , Solventes/farmacologia , Traumatismos da Medula Espinal/fisiopatologia
2.
Proc Natl Acad Sci U S A ; 116(49): 24696-24706, 2019 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-31740590

RESUMO

The avian predentary is a small skeletal structure located rostral to the paired dentaries found only in Mesozoic ornithuromorphs. The evolution and function of this enigmatic element is unknown. Skeletal tissues forming the predentary and the lower jaws in the basal ornithuromorph Yanornis martini are identified using computed-tomography, scanning electron microscopy, and histology. On the basis of these data, we propose hypotheses for the development, structure, and function of this element. The predentary is composed of trabecular bone. The convex caudal surface articulates with rostromedial concavities on the dentaries. These articular surfaces are covered by cartilage, which on the dentaries is divided into 3 discrete patches: 1 rostral articular cartilage and 2 symphyseal cartilages. The mechanobiology of avian cartilage suggests both compression and kinesis were present at the predentary-dentary joint, therefore suggesting a yet unknown form of avian cranial kinesis. Ontogenetic processes of skeletal formation occurring within extant taxa do not suggest the predentary originates within the dentaries, nor Meckel's cartilage. We hypothesize that the predentary is a biomechanically induced sesamoid that arose within the soft connective tissues located rostral to the dentaries. The mandibular canal hosting the alveolar nerve suggests that the dentary teeth and predentary of Yanornis were proprioceptive. This whole system may have increased foraging efficiency. The Mesozoic avian predentary apparently coevolved with an edentulous portion of the premaxilla, representing a unique kinetic morphotype that combined teeth with a small functional beak and persisted successfully for ∼60 million years.


Assuntos
Bico/anatomia & histologia , Aves/fisiologia , Dinossauros/anatomia & histologia , Cinese/fisiologia , Crânio/anatomia & histologia , Animais , Bico/fisiologia , Evolução Biológica , Aves/anatomia & histologia , Dinossauros/fisiologia , Fósseis/anatomia & histologia , Crânio/fisiologia
3.
Technol Health Care ; 27(S1): 345-356, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31045552

RESUMO

BACKGROUND: Most fall intervention studies attempted to improve the mobility, range of motion of upper and lower extremities, or all major muscle strengths. Yet, there has been little effort to identify movements or actions that may be mainly responsible for recovering from a slipping. It was imperative to link lower extremity kinematics in conjunction with the functional anatomy of lower extremity muscles during forward heel-slipping to identify what muscles should have been activated substantially if a person would have recovered from forward heel-slipping. OBJECTIVE: The present study investigated lower extremity movements, such as the ankle, knee, and hip rotations, which could contribute to falls from forward heel-slipping. Determining changes in positions of foot, shank, and thigh during slipping would provide information to develop the optimal training regimen or interventions that may be effective for improving a chance to recover from the postural disturbance. METHODS: Twenty healthy adults (24-68 years old) participated in this experiment. Among twenty participants, only eight participants' data were analyzed in this study. The 3D position data were used to compute the sagittal foot, shank, and thigh angles and frontal thigh angle. RESULTS: The study results indicated that, during the period of slipping, the angles of the segments of the slipping leg were different from that of the foot, shank, and thigh when walking ordinarily over the dry surface in the present study. CONCLUSIONS: The characteristics or differences in the angular kinematics of lower extremity during unexpected slips in the present study demonstrate possible causes for slip-induced falls.


Assuntos
Cinese/fisiologia , Extremidade Inferior/fisiologia , Caminhada/fisiologia , Acidentes por Quedas/prevenção & controle , Adulto , Idoso , Pé/fisiologia , Análise da Marcha , Humanos , Pessoa de Meia-Idade , Adulto Jovem
4.
Rev. int. med. cienc. act. fis. deporte ; 19(73): 33-44, mar. 2019. graf, tab
Artigo em Espanhol | IBECS | ID: ibc-183151

RESUMO

El objetivo de la presente investigación fue determinar la influencia de las variables relacionadas con la aplicación de fuerza y el desplazamiento del centro de masas en las diferencias en la altura saltada entre el salto sin contramovimiento (SJ) y el salto con contramovimiento (CMJ). Participaron veintiséis hombres, realizando tres SJ y tres CMJ con 90° de flexión de rodilla. El desplazamiento del centro de masas y la fuerza media durante la fase de propulsión fueron significativamente superiores en el CMJ en comparación con el SJ, explicando el 75% de la diferencia entre los dos saltos y teniendo un 30% más de influencia el desplazamiento del centro de masas. No hubo diferencias en la fuerza máxima. Los resultados sugieren la necesidad de examinar el desplazamiento del centro de masas para interpretar adecuadamente las diferencias entre el SJ y el CMJ cuando el criterio establecido es 90° de flexión de rodilla


The aim of this investigation was to determine the influences of force application related variables and center of mass displacement on jump height differences between squat jump (SJ) and countermovement jump (CMJ). Twenty six males performed three squat jumps and three countermovement jumps with a 90° knee flexion. The center of mass displacement during the upward movement phase and the average force were significantly greater in CMJ than in SJ. Both variables explained 75% of the differences in the flight height, having 30% more influence the center of mass displacement. There were no differences in peak force. The results of this research suggest the need to examine the center of mass displacement during SJ and CMJ when a 90°of knee flexion criteria is established


Assuntos
Humanos , Masculino , Adolescente , Adulto Jovem , Fenômenos Biomecânicos/fisiologia , Cinese/fisiologia , Resistência à Tração/fisiologia
5.
Ann R Coll Surg Engl ; 100(4): 267-274, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29484928

RESUMO

Introduction The aim of this study was to compare kinetical data from gait analysis of patients who have undergone total and uni-condylar knee replacement. Materials and methods Thirteen patients with unilateral total knee arthroplasty (TKA) and 13 unicondylar knee arthroplasty (UKA), were included, all performed by the same surgeon more than one year prior. The Vicon gait analysis system was used. Statistical power was calculated using SPSS. Results No significant difference was found in the spatiotemporal parameters of gait and survival years of the knee prosthesis between the two groups. The UKA group was found to have significantly larger moments than the TKA group in knee adduction on the operated side and knee flexion moment on the unoperated side during the loading phase. The maximum and minimum sagittal plane moments of the operated sides in the TKA group were significantly lower than the unoperated side. The difference was most significant at pre-swing. The maximum and minimum moments on the operated sides in the UKA group were significantly lower for the knee flexion and adduction moments when compared with the unoperated side and were most prevalent during the loading phase. Conclusions These results are relevant in terms of prosthesis wear. The TKA knees had smaller magnitude moments than the UKA knees in the sagittal and coronal planes. This could explain the higher revision rates for UKA. In both groups, the non-operated knees had significantly larger moments than the operated knees, which implies that after unilateral knee replacement of either type, the non-operated knee is being put under greater stress.


Assuntos
Artroplastia do Joelho/métodos , Marcha/fisiologia , Articulação do Joelho/fisiologia , Osteoartrite do Joelho/cirurgia , Idoso , Artroplastia do Joelho/efeitos adversos , Artroplastia do Joelho/instrumentação , Fenômenos Biomecânicos , Índice de Massa Corporal , Feminino , Seguimentos , Humanos , Cinese/fisiologia , Articulação do Joelho/cirurgia , Prótese do Joelho/efeitos adversos , Masculino , Falha de Prótese , Amplitude de Movimento Articular
6.
J Bodyw Mov Ther ; 21(3): 664-672, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28750982

RESUMO

Closed kinematic chains (CKCs) are widely used in mechanical engineering because they provide a simple and efficient mechanism with multiple applications, but they are much less appreciated in living tissues. Biomechanical research has been dominated by the use of lever models and their kinematic analysis, which has largely ignored the geometric organization of these ubiquitous and evolutionary-conserved systems, yet CKCs contribute substantially to our understanding of biological motion. Closed-chain kinematics couple multiple parts into continuous mechanical loops that allow the structure itself to regulate complex movements, and are described in a wide variety of different organisms, including humans. In a biological context, CKCs are modular units nested within others at multiple size scales as part of an integrated movement system that extends throughout the organism and can act in synergy with the nervous system, where present. They provide an energy-efficient mechanism that enables multiple mechanical functions to be optimized during embryological development and increases evolutionary diversity.


Assuntos
Simulação por Computador , Cinese/fisiologia , Modelos Biológicos , Movimento/fisiologia , Fenômenos Biomecânicos , Humanos
7.
Zh Vyssh Nerv Deiat Im I P Pavlova ; 66(4): 484-492, 2016 07.
Artigo em Russo | MEDLINE | ID: mdl-30695526

RESUMO

The study was performed on a contagious behavior model based on drinking, behavior in rats. In the presence of familiar drink-motivated conspecific showing drinking behavior (rat-demonstrator), drink-unmotivated rat-viewer begins to demonstrate behavioral signs ofdrinking motivation that is the signs of behavioral contagion. In this paper; the changes in the ethogram of rats-viewers with behavioral contagion were studied by analyzing atransition probabilities matrix. Those animals showed a decrease in the frequency of aggression and defensive behavior patterns simultaneously with an increase in the frequency of exploratory activity, drinking and exploratory approaches to bottles as compared with the ethogram of rats-viewers with no signs of behavioral contagion when tested in the presence of familiar drink-unmotivated con specific-demonstrator.


Assuntos
Comportamento de Ingestão de Líquido/fisiologia , Ingestão de Líquidos/fisiologia , Comportamento Exploratório/fisiologia , Comportamento Imitativo/fisiologia , Agressão/fisiologia , Animais , Animais não Endogâmicos , Reação de Fuga/fisiologia , Asseio Animal/fisiologia , Resposta de Imobilidade Tônica/fisiologia , Cinese/fisiologia , Masculino , Motivação/fisiologia , Ratos
8.
J Electromyogr Kinesiol ; 25(2): 265-72, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25465982

RESUMO

Although maximum height (H(max)), muscle force (F), and power output (P), have been routinely obtained from maximum vertical jumps for various purposes, a possible role of the countermovement depth (H(cmd)) on the same variables remains largely unexplored. Here we hypothesized that (1) the optimum H(cmd) for maximizing H(max) exists, while (2) an increase in H(cmd) would be associated with a decrease in both F and P. Professional male basketball players (N=11) preformed maximum countermovement jumps with and without arm swing while varying H(cmd)±25 cm from its preferred value. Although regression models revealed a presence of optimum H(cmd) for maximizing H(max), H(max) revealed only small changes within a wide range of H(cmd). The preferred H(cmd) was markedly below its optimum value (p < .05). However, both F and P sharply decreased with H(cmd), while F also revealed a minimum for H(cmd) close to its highest values. Therefore, we conclude that although the optimum H(cmd) should exists, the magnitude of its effect on H(max) should be only minimal within a typical H(cmd) range. Conversely, F and P of leg muscles assessed through maximum vertical jumps should be taken with caution since both of them could be markedly confounded by H(cmd).


Assuntos
Basquetebol/fisiologia , Teste de Esforço/métodos , Cinese/fisiologia , Perna (Membro)/fisiologia , Movimento/fisiologia , Músculo Esquelético/fisiologia , Fenômenos Biomecânicos/fisiologia , Humanos , Masculino , Adulto Jovem
9.
Vet Comp Orthop Traumatol ; 27(6): 453-60, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25328077

RESUMO

OBJECTIVES: To determine ground reaction forces, head and pelvis vertical motion (HVM and PVM, respectively), and thoraco-lumbar lateral angular motion (LAM) of the spine using kinematic gait analysis in dogs with mild asymmetric weight-bearing of the pelvic limbs while trotting. METHODS: Twenty-seven hound-type dogs were fitted with reflective markers placed on the sagittal crest of the skull, the ischiatic tuberosity, and thoracolumbar spine of dogs to track motion while trotting. Kinetic and kinematic data were used to characterize asymmetry between the left and right pelvic limbs, and to describe HVM, PVM and thoraco-lumbar LAM. Maximum and minimum position and total motion values were determined for each measured variable. RESULTS: Dogs with asymmetric weight bearing of the pelvic limbs had greater PVM on the side with a greater peak vertical force (PVF), and greater thoraco-lumbar LAM toward the side with a lower PVF while trotting. No differences in mean HVM were detected, and there were no significant correlations between the magnitude of HVM, PVM and thoraco-lumbar LAM and the degree of asymmetric weight bearing. CLINICAL SIGNIFICANCE: Dogs with subtle asymmetric weight bearing of a pelvic limb had patterns of body motion that may be useful in identifying subtle lameness in dogs; greater PVM on the side with greater weight bearing and greater thoraco-lumbar LAM toward the side with less weight bearing while trotting. Description of these compensatory movements is valuable when evaluating dogs with subtle weight bearing asymmetry in the pelvic limbs and may improve the sensitivity of lameness detection during subjective clinical lameness examination.


Assuntos
Cães/fisiologia , Movimentos da Cabeça/fisiologia , Locomoção/fisiologia , Vértebras Lombares/fisiologia , Movimento/fisiologia , Pelve/fisiologia , Vértebras Torácicas/fisiologia , Suporte de Carga/fisiologia , Animais , Fenômenos Biomecânicos/fisiologia , Cinese/fisiologia
10.
Astrobiology ; 14(3): 205-15, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24621307

RESUMO

The gravity-dependent behavior of Paramecium biaurelia and Euglena gracilis have previously been studied on ground and in real microgravity. To validate whether high magnetic field exposure indeed provides a ground-based facility to mimic functional weightlessness, as has been suggested earlier, both cell types were observed during exposure in a strong homogeneous magnetic field (up to 30 T) and a strong magnetic field gradient. While swimming, Paramecium cells were aligned along the magnetic field lines; orientation of Euglena was perpendicular, demonstrating that the magnetic field determines the orientation and thus prevents the organisms from the random swimming known to occur in real microgravity. Exposing Astasia longa, a flagellate that is closely related to Euglena but lacks chloroplasts and the photoreceptor, as well as the chloroplast-free mutant E. gracilis 1F, to a high magnetic field revealed no reorientation to the perpendicular direction as in the case of wild-type E. gracilis, indicating the existence of an anisotropic structure (chloroplasts) that determines the direction of passive orientation. Immobilized Euglena and Paramecium cells could not be levitated even in the highest available magnetic field gradient as sedimentation persisted with little impact of the field on the sedimentation velocities. We conclude that magnetic fields are not suited as a microgravity simulation for gravitactic unicellular organisms due to the strong effect of the magnetic field itself, which masks the effects known from experiments in real microgravity.


Assuntos
Euglena gracilis/fisiologia , Euglena longa/fisiologia , Cinese/fisiologia , Campos Magnéticos , Paramecium/fisiologia , Simulação de Ausência de Peso/métodos , Ausência de Peso
11.
Hum Mov Sci ; 33: 97-107, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24074906

RESUMO

There are many aspects of cutting movements that can limit performance, however, the implementation of lateral banking may reduce some of these limitations. Banking could provide a protective mechanism, placing the foot and ankle in orientations that keep them out of dangerous positions. This study sought to determine the effect of two banking angles on the kinematics and kinetics of the lower extremity during two athletic maneuvers. Kinematic and kinetic data were collected on 10 recreational athletes performing v-cuts and side shuffle movements on different banked surfaces (0°, 10°, 20°). Each sample surface was rigidly attached to the force platform. Joint moments were calculated and compared between conditions using a repeated measures ANOVA. Banking had a pronounced effect on the ankle joint. As banking increased, the amount of joint loading in the transverse and frontal planes decreased likely leading to a reduction in injury risk. Also an increase in knee joint loading in the frontal plane was seen during the 20° bank during the v-cut. Conversely loading in the sagittal plane at the ankle joint increased with banking and coupled with a reorientation of the ground reaction vector may facilitate a performance increase. The current study indicates that the 10° bank may be the optimal bank, in that it decreases ankle joint loading, as well as increases specific performance variables while not increasing frontal plane knee joint loading. If banking could be incorporated in footwear it may be able to provide a protective mechanism for athletes.


Assuntos
Traumatismos do Tornozelo/fisiopatologia , Articulação do Tornozelo/fisiopatologia , Traumatismos em Atletas/fisiopatologia , Fenômenos Biomecânicos/fisiologia , Traumatismos do Joelho/fisiopatologia , Articulação do Joelho/fisiopatologia , Orientação/fisiologia , Equilíbrio Postural/fisiologia , Corrida/lesões , Entorses e Distensões/fisiopatologia , Suporte de Carga/fisiologia , Traumatismos do Tornozelo/prevenção & controle , Traumatismos em Atletas/prevenção & controle , Humanos , Cinese/fisiologia , Traumatismos do Joelho/prevenção & controle , Valores de Referência , Entorses e Distensões/prevenção & controle , Adulto Jovem
12.
Gait Posture ; 39(1): 241-6, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23953274

RESUMO

This study investigated the effect of both walking speed and external ankle load on the kinetic patterns of treadmill walking in preadolescents with and without Down syndrome (DS). Ten preadolescents with DS and ten age- and gender-matched children with typical development (TD) participated in this study. We manipulated two treadmill speeds and two external ankle loads. Treadmill speeds were equal to 75% and 100% of the preferred overground walking speed. Two load conditions were with and without external ankle load which was equal to 2% of body weight on each side. We used an instrumented treadmill to collect vertical ground reaction force (GRF). Both timing and magnitude of peak GRFs, the loading and unloading rates, and various impulses were calculated from the GRF data. The results show that the DS group produced a shorter duration of propulsion, a lower FZ2 (second peak GRF) and vertical propulsive impulse, a higher loading rate and a lower unloading rate than the TD group. At a faster treadmill speed the DS group increased the duration of propulsion, the unloading rate and the vertical propulsive impulse, but reduced the magnitude of FZ2. External ankle load helped the DS group increase FZ2 and vertical propulsive impulse and might facilitate the push off and the initiation of leg swing during treadmill walking. External ankle load may therefore be included in the future physical intervention and exercise programs for the DS group to strengthen leg muscles and develop more efficient push off during locomotion.


Assuntos
Síndrome de Down/fisiopatologia , Teste de Esforço/métodos , Cinese/fisiologia , Músculo Esquelético/fisiopatologia , Equilíbrio Postural/fisiologia , Caminhada/fisiologia , Peso Corporal , Criança , Síndrome de Down/diagnóstico , Feminino , Humanos , Masculino , Exame Físico
13.
Vestn Otorinolaringol ; (4): 33-6, 2012.
Artigo em Russo | MEDLINE | ID: mdl-23011366

RESUMO

The objective of the present study was to estimate the efficacy of the tools and methods for the optimization of the activity of the central nervous system (CNS) and analyzers involved in the maintenance of the statokinetic (SK) stability in man. To this effect, we evaluated the outcome of bemitil treatment during 10 days with and without A.I. Yarotsky test and the influence of these procedures on the pathophysiological characteristics of selected elements of the work of operators of aerospace systems. Based on the data obtained in the study, the tools and methods have been developed that allow the efficacy and quality of certain aspects of the operators' activity to be improved, viz. general working capacity under conditions requiring enhanced statokinetic stability, self-confidence, emotional and somatic comfort.


Assuntos
Benzimidazóis , Habituação Psicofisiológica , Militares/psicologia , Senso de Coerência/fisiologia , Enjoo devido ao Movimento em Voo Espacial/prevenção & controle , Medicina Aeroespacial/métodos , Antioxidantes/uso terapêutico , Benzimidazóis/uso terapêutico , Sistema Nervoso Central/efeitos dos fármacos , Sistema Nervoso Central/fisiologia , Habituação Psicofisiológica/efeitos dos fármacos , Habituação Psicofisiológica/fisiologia , Humanos , Cinese/efeitos dos fármacos , Cinese/fisiologia , Masculino , Testes Neuropsicológicos , Voo Espacial , Enjoo devido ao Movimento em Voo Espacial/fisiopatologia , Análise e Desempenho de Tarefas , Vestíbulo do Labirinto/efeitos dos fármacos , Vestíbulo do Labirinto/fisiologia , Recursos Humanos , Adulto Jovem
14.
Rev. psicol. deport ; 20(2): 383-400, jul.-dic. 2011. ilus
Artigo em Espanhol | IBECS | ID: ibc-93901

RESUMO

En el seno de la metodología observacional, mediante la detección de patrones temporales ocultos, el presente trabajo estudia las rutinas gestuales previas a los tiros libres de baloncesto que desarrollan jugadores en formación -en concreto, niños de 11-12 años incluidos en la categoría alevín-. Utilizando el programa Theme –versión 5.0–, se analiza tipo, secuencia y tiempo de ejecución de las conductas gestuales que constituyen estas rutinas gestuales. el trabajo se completa, a partir de la interpretación de los resultados obtenidos, con una propuesta general de intervención en el desarrollo de las rutinas previas al tiro libre en baloncesto en categorías de formación (AU)


Using the observational methodology as a work method, this article studies the gestural routines employed by eleven to twelve-year old children before free throws in basketball. Using the 5.0 version of the Theme program to discover hidden patterns, we have analysed movement behaviours and their variations in sequence and timing. The article concludes with a general proposition for possible areas of intervention in the development of preshooting gestural routines in basketball free throws (AU)


Assuntos
Humanos , Masculino , Adolescente , Basquetebol/psicologia , Sinais e Sintomas , Esportes/psicologia , Expressão Facial , Cinese/fisiologia , Basquetebol/normas , Basquetebol/tendências
16.
Hum Mov Sci ; 30(2): 279-95, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21435732

RESUMO

The reaction to an unexpected balance disturbance is unpracticed, often startling and frequently associated with falls. This everyday situation can be reproduced in an experimental setting by exposing standing humans to sudden, unexpected and controlled movements of a support surface. In this review, we focus on the responses to the very first balance perturbation, the so-called first trial reactions (FTRs). Detailed analysis of FTRs may have important implications, both for clinical practice (providing new insights into the pathophysiological mechanisms underlying accidental falls in real life) and for understanding human physiology (what triggers and mediates these FTRs, and what is the relation to startle responses?). Several aspects of the FTRs have become clear. FTRs are characterized by an exaggerated postural reaction, with large EMG responses and co-contracting muscles in multiple body segments. This balance reaction is associated with marked postural instability (greater body sway to the perturbation). When the same perturbation is repeated, the size of the postural response habituates and the instability disappears. Other issues about FTRs remain largely unresolved, and these are addressed here. First, the functional role of FTRs is discussed. It appears that FTRs produce primarily increased trunk flexion during the multi-segmental response to postural perturbations, thus producing instability. Second, we consider which sensory signals trigger and modulate FTRs, placing specific emphasis on the role of vestibular signals. Surprisingly, vestibular signals appear to have no triggering role, but vestibular loss leads to excessive upper body FTRs due to loss of the normal modulatory influence. Third, we address the question whether startle-like responses are contributing to FTRs triggered by proprioceptive signals. We explain why this issue is still unresolved, mainly because of methodological difficulties involved in separating FTRs from 'pure' startle responses. Fourth, we review new work about the influence of perturbation direction on FTRs. Recent work from our group shows that the largest FTRs are obtained for toe-up support surface rotations which perturb the COM in the posterior direction. This direction corresponds to the directional preponderance for falls seen both in the balance laboratory and in daily life. Finally, we briefly touch upon clinical diagnostic issues, addressing whether FTRs (as opposed to habituated responses) could provide a more ecologically valid perspective of postural instability in patients compared to healthy subjects. We conclude that FTRs are an important source of information about human balance performance, both in health and disease. Future studies should no longer discard FTRs, but routinely include these in their analyses. Particular emphasis should be placed on the link between FTRs and everyday balance performance (including falls), and on the possible role played by startle reactions in triggering or modulating FTRs.


Assuntos
Cinestesia/fisiologia , Doença de Parkinson/fisiopatologia , Equilíbrio Postural/fisiologia , Doenças Vestibulares/fisiopatologia , Suporte de Carga/fisiologia , Acidentes por Quedas , Fenômenos Biomecânicos , Eletromiografia , Lateralidade Funcional/fisiologia , Habituação Psicofisiológica , Humanos , Cinese/fisiologia , Contração Muscular/fisiologia , Músculo Esquelético/fisiopatologia , Propriocepção/fisiologia , Tempo de Reação/fisiologia , Reflexo de Sobressalto/fisiologia , Vestíbulo do Labirinto/fisiopatologia
17.
J Oral Rehabil ; 38(9): 680-5, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21284690

RESUMO

Tongue pressure measured with a disposable hand-held balloon probe has been used for assessing tongue function; however, no diagnostic standard for assessing other oral functions exists currently. In this study, to develop a method for multifactorial manometric evaluation of oral functions, 20 men and 20 women (21-32 years of age) were instructed to apply 7-s maximal voluntary muscular effort on a hand-held balloon probe placed against the anterior and lateral parts of the palate, buccal surface of the molars on the habitual chewing side and labial surface of the anterior teeth for measuring anterior and posterior tongue, cheek and lip pressures (LPs), respectively. Intra-session reproducibility was determined by three repeated measurements, and associations between the obtained and the conventional data on oral diadochokinesis were tested. The men exhibited higher values of all the pressure types. Further, both genders showed a positive correlation between anterior and posterior tongue pressures (PTPs) (P < 0·05), but only the women exhibited positive correlations between anterior tongue and cheek pressures, cheek and PTPs, anterior tongue and LPs, and cheek and LPs (P < 0·05). No statistically significant correlation was found between the pressures and the number of syllabic articulations, except between LP and the number of /pa/ articulations in the women (r = 0·524, P < 0·05). In conclusion, the balloon probe method enables objective manometric evaluation of oral functions and could be an effective tool for clinical epidemiological studies and evidence-based decision-making in nursing care.


Assuntos
Bochecha/fisiologia , Cinese/fisiologia , Boca/fisiologia , Adulto , Feminino , Humanos , Japão , Lábio/fisiologia , Masculino , Manometria/instrumentação , Boca/fisiopatologia , Pressão , Fatores Sexuais , Língua/fisiologia , Adulto Jovem
18.
Nat Neurosci ; 13(12): 1463-71, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21037580

RESUMO

Radial glial progenitor cells exhibit bidirectional cell cycle-dependent nuclear oscillations. The purpose and underlying mechanism of this unusual 'interkinetic nuclear migration' are poorly understood. We investigated the basis for this behavior by live imaging of nuclei, centrosomes and microtubules in embryonic rat brain slices, coupled with the use of RNA interference (RNAi) and the myosin inhibitor blebbistatin. We found that nuclei migrated independent of centrosomes and unidirectionally away from or toward the ventricular surface along microtubules, which were uniformly oriented from the ventricular surface to the pial surface of the brain. RNAi directed against cytoplasmic dynein specifically inhibited nuclear movement toward the apical surface. An RNAi screen of kinesin genes identified Kif1a, a member of the kinesin-3 family, as the motor for basally directed nuclear movement. These observations provide direct evidence that kinesins are involved in nuclear migration and neurogenesis and suggest that a cell cycle-dependent switch between distinct microtubule motors drives interkinetic nuclear migration.


Assuntos
Movimento Celular/fisiologia , Núcleo Celular/fisiologia , Dineínas do Citoplasma/fisiologia , Células-Tronco Embrionárias/fisiologia , Cinesinas/fisiologia , Células-Tronco Neurais/fisiologia , Animais , Ciclo Celular/fisiologia , Células-Tronco Embrionárias/citologia , Cinese/fisiologia , Microtúbulos/fisiologia , Células-Tronco Neurais/citologia , Células PC12 , Ratos
19.
Pain ; 150(3): 492-500, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20598804

RESUMO

For musculoskeletal disorders like low back pain and fibromyalgia, evidence is growing for fear of movement to play an important role in the development of chronic pain. In temporomandibular disorder (TMD) patients, however, this construct has not received any attention yet. Therefore, in this paper, (1) a generally used instrument to measure fear of movement, the Dutch version of the Tampa Scale for Kinesiophobia (TSK), was adapted for its use in TMD patients (and translated for equivalence to English), (2) the psychometric properties of the Dutch version of the TSK-TMD were assessed, and (3) the association of various symptoms of TMD (i.e., pain, joint sounds, and limited jaw movements) with fear of movement was evaluated. In a sample of TMD patients (N=301), confirmatory factor analysis indicated that a two-factor model based on 12 items provides the best fit of the TSK-TMD, with activity avoidance and somatic focus as its subscales. This two-factor solution of the Dutch TSK-TMD has generally good reliability and convergent validity. Multiple regression analysis showed that TMD functional problems (i.e., temporomandibular joint sounds or a stuck/locked feeling) were more strongly associated with fear of movement than with pain. This finding leads to new perspectives regarding the interplay between musculoskeletal complaints, cognition, and avoidance behavior. The results provide a basis for use of the 12-item version for routine assessment of fear of movement in TMD patients, and for future clinical studies, for example, to the role of fear of movement in TMD-treatment success.


Assuntos
Cinese/fisiologia , Transtornos Fóbicos/diagnóstico , Transtornos Fóbicos/etiologia , Psicometria/métodos , Transtornos da Articulação Temporomandibular/complicações , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Medo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Movimento/fisiologia , Medição da Dor/métodos , Reprodutibilidade dos Testes , Transtornos da Articulação Temporomandibular/psicologia , Adulto Jovem
20.
Arthritis Res Ther ; 12(2): R41, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20222952

RESUMO

INTRODUCTION: Pristane-induced arthritis (PIA) in the rat has been described as an animal model of inflammatory arthritis which exhibits features similar to rheumatoid arthritis in humans, such as a chronic, destructive, and symmetrical involvement of peripheral joints. However, so far little is known about the earliest inflammatory events and their influence on locomotor behaviour during the course of PIA. To investigate this issue a detailed analysis of the pathologic changes occurring during the prodromal and early stages of PIA was performed. METHODS: Arthritis was induced in DA.rats by injection of 150 microl 2,6,10,4-tetramethyl-pentadecane (pristane) at the base of the tail and changes in locomotor behaviour of the affected paws were monitored using the CatWalk quantitative gait analysis system. The pathologic events occurring in the joints of pristane-injected animals were studied before onset, at onset, and during acute phase of arthritis by histological methods. RESULTS: Gait analysis revealed that changes in locomotion such as reduced paw print areas and stance phase time are already apparent before the onset of clinically discernible arthritis symptoms (erythema, paw swelling) and correlate with PIA scores. In agreement with these findings, inflammatory tenosynovitis could be observed by histology already before the onset of erythema and swelling of the respective paws. In the most heavily affected rats also irregularities in step sequence patterns occurred A kinetic analysis of clinical and histological findings demonstrated that gait changes precede the pathological changes occurring during the acute phase of pristane-induced arthritis. CONCLUSIONS: Gait analysis allows for pinpointing the initial inflammatory changes in experimental arthritis models such as pristane-induced arthritis. Analysis of early clinically relevant symptoms in arthritis models may facilitate the search for novel therapeutics to interfere with pain, inflammation and joint destruction in patients suffering from inflammatory arthritis.


Assuntos
Artrite Experimental/fisiopatologia , Marcha/fisiologia , Articulações/fisiopatologia , Coxeadura Animal/fisiopatologia , Animais , Artrite Experimental/induzido quimicamente , Feminino , Marcha/efeitos dos fármacos , Membro Posterior/efeitos dos fármacos , Membro Posterior/patologia , Membro Posterior/fisiopatologia , Articulações/efeitos dos fármacos , Articulações/patologia , Cinese/efeitos dos fármacos , Cinese/fisiologia , Coxeadura Animal/induzido quimicamente , Locomoção/efeitos dos fármacos , Locomoção/fisiologia , Masculino , Ratos , Ratos Endogâmicos , Tenossinovite/induzido quimicamente , Tenossinovite/patologia , Tenossinovite/fisiopatologia , Terpenos , Fatores de Tempo
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