A disturbed processing of graviceptive pathways may be involved in the pathophysiology of balance disorders in patients with multiple sclerosis / O processamento incorreto das informações graviceptivas pode estar envolvido na fisiopatologia dos distúrbios do equilíbrio em pacientes com esclerose múltipla

ABSTRACT The purpose of this study was to determine the relationship between perception of verticality and balance disorders in multiple sclerosis patients. We evaluated patients and healthy controls. Patients were divided into two groups according to their risk of fall, with or without risk of fall, measured by a Dynamic Gait Index scale. Graviceptive perception was assessed using the subjective visual vertical test. Patients with risk of fall showed worse perception than those without risk of fall, p < 0.001. Misperception of verticality was correlated with the dynamic gait index scores (p < 0.001), suggesting that the larger the error for verticality judgment, the greater risk for falling. Considering that the perception of verticality is essential for postural control, our results suggested that the disturbed processing of graviceptive pathways may be involved in the pathophysiology of balance disorders in these patients.

RESUMO Nosso objetivo foi determinar a relação entre percepção de verticalidade e alterações do equilíbrio em pacientes com esclerose múltipla (EM). Foram avaliados pacientes e sujeitos saudáveis. Pacientes foram divididos em dois grupos de acordo com o risco de queda, mensurado pelo Índice de marcha dinâmica, formando os grupos com risco e sem risco de quedas. A percepção da verticalidade foi medida através do teste vertical visual subjetiva (VVS). Pacientes com risco de queda apresentaram pior percepção da verticalidade quando comparados aos sem risco, p < 0,001. O desempenho no teste da VVS foi pior em pacientes quando comparado aos controles (p < 0,001). O erro no julgamento da verticalidade foi correlacionado aos índices de risco de queda (p < 0,001), sugerindo que quanto maior o erro no julgamento da verticalidade, maior o risco de queda dos pacientes. Nossos resultados sugerem que alterações das informações em vias graviceptivas podem estar envolvidas nas alterações de equilíbrio dessa população.

O uso do centro articular do quadril e do centro de gravidade da cabeça como referência na estimativa de parâmetros cinemáticos da performance em corridas de velocidade / The use of the hip joint center and head gravity center as a reference to estimate the performance kinematics parameters in speed races

O objetivo deste estudo foi comparar a velocidade e o deslocamento do centro de gravidade global (CGG) com as centro de gravidade da cabeça (CGC) e do centro articular do quadril (CAQ), durante um passo em corridas de velocidade. A partir disso, determinar se tais pontos podem ser utilizados como indicadores de parâmetros da performance nos estudos envolvendo a cinemática das corridas. Participaram deste estudo 8 sujeitos do sexo masculino, com idade média de 12,5 ± 0,66 anos e estatura média de 163,00 ± 5,40 cm. Realizou-se uma análise cinemática da corrida, utilizando-se o método de videografia tridimensional, com quatro câmeras de vídeo do sistema de análise do movimento Peak Motus, operando na freqüência de 180 Hz. As variáveis analisadas foram deslocamento, velocidade média e velocidade instantânea horizontal do CGG, CGC e CAQ referentes a um passo. Os resultados encontrados mostraram não haver diferenças significativas na velocidade média e amplitude de deslocamento entre os três pontos analisados. Em relação à velocidade instantânea analisada em todo passo, não verificou-se diferenças significativas, porém, as variações na curva de velocidade do CAQ não ocorreram na mesma escala de tempo quando comparado com os demais pontos. Concluiu-se assim que, tanto o CGG, assim como o CGC e CAQ, podem ser utilizados para descrever parâmetros cinemáticos da corrida, quando o objetivo da análise referir-se a deslocamentos e velocidade média de um passo. Em relação à descrição da velocidade instantânea do atleta nas diferentes fases do passo, o uso do CGG e CGC parecem ser os mais adequados a serem utilizados.

The objective of this study was to compare the speed and the displacement of the global gravity center (CGG) with the head gravity center (CGC) and the hip joint center (CAQ) during a step in speed races. After, to determine if these points could be used as indicators of the performance parameters in the studies involving the kinematics of the speed races. To accomplish this study, eight male subjects participated. They were around 12.5 ± 0.66 years old and their average height was 163.00 ± 5.40 cm. A kinematic analysis of the running was carried out by using the method of three-dimensional videography, with four video cameras of the Peak Motus system operating in the frequency of 180 Hz. The analyzed variables were displacement, average speed and horizontal instantaneous speed of CGG, CGC and CAQ that refer to one step. The results showed that there are not significant statistical differences in both the average speed and the displacement amplitude among the three analyzed points. Concerning the instantaneous speed analyzed in the whole step, no significant differences were found. However, the variations in the CAQ speed curve did not occur in the same scale of time when compared with the other points. Thus, one concluded that the CGG, the CGC and the CAQ can be used to describe kinematics parameters of the running when the aim of analysis refers to displacement and average speed of one step. Concerning the description of instantaneous speed of athletes in different step phases, the use of CGG and CGC seems to be the most appropriate.

Evaluation of diagnosing cervical vertigo with computerized static posturography / 中国骨伤

<p><b>OBJECTIVE</b>To provide a quantitative base for diagnosing cervical vertigo by establishing a biomechanics method.</p><p><b>METHODS</b>From July 2004 to Nov 2005, the static posturography (SPG) of normal 86 health individuals and 75 patients with cervical vertigo were quantitatively measured and qualitative diagnosis respectively in closed and open eyes. There were 40 male and 46 female in health adults, ranging from 20 to 74 years old (mean 30 years). There were 16 male and 59 female in vertigo patients, ranging from 20 to 74 years old (mean 44.5 years). In contrast to current diagnosis method of patients with cervical vertigo, the clinical value was evaluated.</p><p><b>RESULTS</b>Under the state of closed eyes, the sensitivity of SPG diagnosing cervical vertigo was 76%; the specificity was 93%; the Youden index was 69%; the coincidence was 85.1%; the positive predictive value was 90.5%; the negative predictive value was 93%; the positive and negative likelihood ratio were 10.893 and 0.258 respectively. Under the state of open eyes, the sensitivity was 49.3%; the specificity was 87.2%; the Youden index was 38.6%; the coincidence was 69.6%; the positive predictive value was 77.1%; the negative predictive value was 87.2%; the positive likelihood ratio was 3.857; the negative one was 0.581. Regardless of closed or open eyes, foreword-backward type shift orbit was the with cervical vertigo.</p><p><b>CONCLUSION</b>The patients with cervical vertigo and normal individuals can be diagnosed objectively and quantitatively with SPG under the state of closed eyes, which can achieve the basic requirements of diagnosing cervical vertigo with validity, reliability and good clinical application. However, the rate of missed diagnosis with SPG under the state of open eyes is too high to meet the diagnostic needs.</p>

(Possible) molecular mechanism of cells in gravisensing / 生物医学工程学杂志

Although it is clear that changes of gravity can alter dramatically the functions and structures of cells, little is known about how living cells sense these signals and convert them into a biochemical response. Recent studies estimated that the changes of gravity might influence the single cell directly and indirectly. So far, the molecular mechanism of gravisensing remains unknown, however, according to a great deal of researches focusing on this point, several pathways could be considered: (1) Pre-stress perception pathway; (2) Cytoskeleton-perception pathway; (3) Stress-sensitive ion channel pathway; (4) Indirect effects of gravitational change.

Secondary stem anatomy and uses of four drought-deciduous species of a tropical dry forest in México

Wood and bark anatomy and histochemistry of Acacia bilimekii Humb. & Bonpl., Acacia cochliacantha Mcbride., Conzatia multiflora (Rob) Stand. and Guazuma ulmifolia Lam.are described from stem samples collected in a tropical dry forest (Morelos,Mexico). Enzyme activities were tested in tangential, radial and transverse cuts of fresh material. Histochemistry and stem anatomy were studied on similar cuts previously softened in a solution of water-glicerol-PEG. Our results show that the anatomical patterns of bark and wood, as well as the histochemical patterns and specific gravity, are influenced by water accessibility and climate; these patterns could guarantee mechanical and anti-infection strategies to support extreme conditions. Enzyme cytochemistry reveals biochemical activities probably related to lipid utilization routes for the lignification processes and for synthesis of extractives; these results suggest that the formation and maturation of woody tissue is very active at the beginning of the rainy season. These species are widely used by the local population. Traditional uses include firewood, dead and live fences, fodder, construction, supporting stakes, handcrafts, farming tools, extraction of tanning products, and medicine. There is no relationship between use and abundance. Alternative uses are proposed according to a density index

Se estudió la anatomía e histoquímica del tallo secundario de Acacia bilimekii, Acacia cochliacantha, Conzatia multiflora y Guazuma ulmifolia. Las muestras de tallo se colectaron en una selva baja caducifolia del estado de Morelos, México. La actividad enzimática se estudió en cortes frescos de caras tangenciales, radiales y transversales. La anatomía e histoquímica se hizo en cortes similares de muestras previamente ablandadas con una mezcla de agua-glicerol-PEG. Los resultados muestran que el patrón anatómico de la corteza y madera, así como las características histoquímicas no enzimáticas están relacionados con el acceso al agua y el clima; estos patrones garantizan que las estrategias mecánicas de resistencia al deterioro les permitan sobrevivir a condiciones extremas. Los resultados de la histoquímica y la citoquímica enzimática sugieren que la lignificación y la síntesis de extractivos a partir de los lípidos de reserva se encuentra activa desde el principio de la estación de lluvias. Se sugieren usos potenciales para las especies estudiads de acuerdo con las densidades relativas

Temas polémicos del IV Congreso Unificado / Polemics subject of the IV Unified Congress

La finalidad de este artículo es la de expresar una posición definida y clara, frente a tres temas polémicos expuestos durante el desarrollo del IV Congreso Unificado de Escuelas Médicas Homeopáticas Argentinas, del 20 al 24 de septiembre de 1994. Los temas de referncia son: 1) La importancia del diagnóstico clínico y el conocimiento de la enfermedad como entidad nosológica. 2) La significación clínico-homeopática de las enfermedades agudas y la actitud correspondiente que se debe observar con las mismas. 3) El estudio y comprensión de la materia médica a través de los simbolismos