Shape Analysis of the Femoral Head: A Comparative Study Between Spherical, (Super)Ellipsoidal, and (Super)Ovoidal Shapes.

In this work, MacConaill's classification that the articular surface of the femoral head is better represented by ovoidal shapes rather than purely spherical shapes is computationally tested. To test MacConaill's classification, a surface fitting framework was developed to fit spheres, ellipsoids, superellipsoids, ovoids, and superovoids to computed tomography (CT) data of the femoral proximal epiphysis. The framework includes several image processing and computational geometry techniques, such as active contour segmentation and mesh smoothing, where implicit surface fitting is performed with genetic algorithms. By comparing the surface fitting error statistics, the results indicate that (super)ovoids fit femoral articular surfaces better than spherical or (super)ellipsoidal shapes.

Critical analysis of musculoskeletal modelling complexity in multibody biomechanical models of the upper limb.

The inverse dynamics technique applied to musculoskeletal models, and supported by optimisation techniques, is used extensively to estimate muscle and joint reaction forces. However, the solutions of the redundant muscle force sharing problem are sensitive to the detail and modelling assumptions of the models used. This study presents four alternative biomechanical models of the upper limb with different levels of discretisation of muscles by bundles and muscle paths, and their consequences on the estimation of the muscle and joint reaction forces. The muscle force sharing problem is solved for the motions of abduction and anterior flexion, acquired using video imaging, through the minimisation of an objective function describing muscle metabolic energy consumption. While looking for the optimal solution, not only the equations of motion are satisfied but also the stability of the glenohumeral and scapulothoracic joints is preserved. The results show that a lower level of muscle discretisation provides worse estimations regarding the muscle forces. Moreover, the poor discretisation of muscles relevant to the joint in analysis limits the applicability of the biomechanical model. In this study, the biomechanical model of the upper limb describing the infraspinatus by a single bundle could not solve the complete motion of anterior flexion. Despite the small differences in the magnitude of the forces predicted by the biomechanical models with more complex muscular systems, in general, there are no significant variations in the muscular activity of equivalent muscles.

Energy expenditure during human gait. I - An optimized model.

Within the framework of multibody dynamics, a 3D large scale neuromusculoskeletal model of the human body is presented. To characterize the dynamics of skeletal muscle, a phenomenological model of energy expenditure was developed for estimating energy consumption during normal locomotion. Such model is able for predicting thermal and mechanical energy liberation under submaximal activation, muscle fiber type, and varying contractile conditions, typically observed in human motion. Future formulations of the indeterminate biomechanical problem, solved through the physiological criteria of minimization of metabolical cost of transport during gait, should consider the role of muscle groups in coordinating multijoint motion. Such an approach is presented in part II of the paper.

Energy expenditure during human gait. II - Role of muscle groups.

A phenomenological model of muscle energy expenditure developed in part I of the paper, is utilized as a physiological cost function to estimate the muscle forces during normal locomotion. The model takes into account muscular behaviors typically observed during human gait, such as submaximal activation, variable muscular contraction conditions and muscular fiber type. The solution of the indeterminate biomechanical problem is obtained by integrating multibody dynamics and the global static optimization technique that considers the whole motion. The results for an application case indicate the important role of muscle groups in coordinating multijoint motion with the objective of minimizing metabolic costs of transport during locomotion.

Estimation of the muscle force distribution in ballistic motion based on a multibody methodology.

This work presents a general three-dimensional multibody procedure for studying the human body motion with emphasis on the locomotion apparatus. The methodology includes a three-dimensional biomechanical model, data acquisition techniques and an inverse dynamics approach. The biomechanical model is based on a multibody formulation using natural coordinates and consists of 16 anatomical segments modeled by 33 rigid bodies for a total of 44 degrees-of-freedom. The action of the muscles is introduced in the equations of motion of the multibody model by means of driver actuators defined as kinematic constraints. By associating a Lagrange multiplier to each muscle actuator the muscle forces became coupled with the biomechanical model through the Jacobian matrix of the underlying multibody system. A Hill type muscle model is used to calculate individual muscle forces. The model for the muscle apparatus comprises 43 muscle groups for each leg, which use the full three-dimensional lines of action for these muscles in their geometric description. The problem of the redundancy of the forces on the musculoskeletal structure is solved by using inverse dynamics and static optimization methods. In the process of describing the methodology the benefits of modeling in natural coordinates are highlighted. The methodology developed is demonstrated through its application to a case of ballistic motion, represented by the take-off to an aerial trajectory in order to estimate the joint torques and the muscle force distribution in the supporting leg. The time characteristics of the resultant net torques at the basic joints of the supporting leg and the time-varying muscle force patterns are presented and discussed. The results obtained are explained in terms of their relevance to the activity under study.

Intra-assay total uncertainty of results in immunoassay techniques.

Uncertainty is a parameter associated with the result of a measurement; this parameter characterizes the dispersion of the values that could reasonably be attributed to the sample. Data processing methods do not take into account the influence of the imprecision and deviation of the experimental points of the calibration system and their impact on the final result of a sample analysis. The aim of this work is: (a) to propose, for each run, a simple method to calculate the uncertainty due to the calibration system (Uc); and (b) to present a method to determine the "intra-assay total uncertainty" (Ut) and evaluate its impact on the final result for an analyte. Ten replicates of standards, controls, and two serum-male and female samples were measured in the same run with a manual kit for determination of testosterone. To calculate Ut, random duplicate responses were selected. For controls and samples, Ut was affected by Uc (2.91% to 6.59%) and by the uncertainty of the measurement of the sample (Us) (1.01 to 8.73%); this allowed us to determine that Ut had values from 3.73% to 9.87%. While Us affects the result of a given sample, Uc affects the result of all the samples with a similar response (cpm). In the method proposed, Ut involves Us and Uc, both factors that introduce variations into the result of a sample by random causes. Intraassay total uncertainty includes the most probable result for the analytical methodology selected.

Sensitivity of the results produced by the inverse dynamic analysis of a human stride to perturbed input data.

The results of the inverse dynamic procedures used in gait analysis are known to be highly dependent on the quality of the kinematic and dynamic input data and on the biomechanical model anatomical data. In this paper the sensitivities of the system response to imprecision in the input data and biomechanical model were calculated. It was shown that the gait analysis results were very sensitive to the identification of the point of application of the external forces. The quality of the results was less sensitive to errors made during motion reconstruction and to uncertainties in the biomechanical anatomical data. In this study it is also shown that the adopted inverse dynamic analysis method, based on natural coordinates, effectively shielded any error made on a particular kinematic chain from propagation to other branches of the biomechanical model.

Relación de la hemoglobina glucosilada materna con el peso relativo del recién nacido hijo de madre diabética / Relationship of maternal glycosylated hemoglobin with relative weight of the newborn infant of diabetic mother

1) La hemoglobina glucosilada está incrementada en las diabéticas gestacionales y mellitus. 2) La hemoglobina glucosilada no se correlaciona con el Péptido C-Insulina e Insulina en líquido amniótico. 3) La hemoglobina glucosilada se correlaciona con la glucosa del líquido amniótico. 4) La Hb. glucosilada no se correlaciona con el peso al nacer (gramos). 5) La Hb glucosilada de todas las embarazadas se correlaciona con peso relativo. 6) La Hb glucosilada materna está aumentada en los Altos Peso para la Edad Gestacional

Relación de la hemoglobina glucosilada materna con el peso relativo del recién nacido hijo de madre diabética / Relationship of maternal glycosylated hemoglobin with relative weight of the newborn infant of diabetic mother

1) La hemoglobina glucosilada está incrementada en las diabéticas gestacionales y mellitus. 2) La hemoglobina glucosilada no se correlaciona con el Péptido C-Insulina e Insulina en líquido amniótico. 3) La hemoglobina glucosilada se correlaciona con la glucosa del líquido amniótico. 4) La Hb. glucosilada no se correlaciona con el peso al nacer (gramos). 5) La Hb glucosilada de todas las embarazadas se correlaciona con peso relativo. 6) La Hb glucosilada materna está aumentada en los Altos Peso para la Edad Gestacional (AU)

Investigaciones sobre correlaciones de las concentraciones en líquido amniótico de peptido C - insulina, insulina y glucosa: su interés para el control del estado fetal en embarazadas diabéticas / Investigations on correlations of the concentrations in amniotic liquid of peptide C - insulin, insulin and glucose: its interest for the control of the fetal state in diabetic pregnant women

1) Hemos encontrado mayor concentración en líquido amniótico de péptido C - insulina, insulina y glucosa en el grupo de embarazadas diabéticas que en el grupo de embarazadas normales. 2) Dentro del grupo de embarazadas diabéticas, aquellas con diabetes gestacional son las que presentaron mayor concentración en líquido amniótico de péptido C - insulina, insulina y glucosa. Si bien en los tres casos estudiados en esta serie no hubo mortalidad perinatal, la experiencia clínica muestra el alto riesgo perinatal en estas pacientes. 3) De los tres parámetros estudiados comprobamos que los valores de péptido C - insulina, son los que fluctúan dentro de un rango menor, por lo cual su error standard es bajo. Esto permite suponer que el péptido C - insulina, es el más confiable en su aplicacion clínica para conocer el estado fetal y predecir la salud del recién nacido en las embarazadas diabéticas. 4) Con valores altos en liquído amniótico, ya sea de péptido C - insulina, insulina o glucosa, hay probabilidades que nazca un recién nacido de alto peso por edad gestacional (A.P.E.G.). 5) Exceptuando el A.P.E.G, la hiperbilirrubinemia del recién nacido, resulto ser la patología que guardó mayor relación con el aumento en la concentración de peptido C - insulina, insulina y glucosa. 6) Considerando el total del material se encontró una alta correlación entre péptido C - insulina e insulina. En diabéticas no pudimos corroborar esta correlación. 7) En las embarazadas con isoinmunización al factor Rh, no encontramos valores superiores a los normales en la concentración en líquido amniótico de los tres parámetros valorados. 8) De acuerdo a nuestros resultados y a los pocos estudios al respecto en la literatura mundial, la determinación de la concentración en líquido amniótico de péptido C - insulina, insulina y glucosa resulta de utilidad para el control del estado fetal en las embarazadas diabéticas. En algunos aspectos de estas investigaciones se necesita estudiar un número mayor de casos, antes de sacar conclusiones de aplicación clínica. (AU)

Investigaciones sobre correlaciones de las concentraciones en líquido amniótico de peptido C - insulina, insulina y glucosa: su interés para el control del estado fetal en embarazadas diabéticas / Investigations on correlations of the concentrations in amniotic liquid of peptide C - insulin, insulin and glucose: its interest for the control of the fetal state in diabetic pregnant women

1) Hemos encontrado mayor concentración en líquido amniótico de péptido C - insulina, insulina y glucosa en el grupo de embarazadas diabéticas que en el grupo de embarazadas normales. 2) Dentro del grupo de embarazadas diabéticas, aquellas con diabetes gestacional son las que presentaron mayor concentración en líquido amniótico de péptido C - insulina, insulina y glucosa. Si bien en los tres casos estudiados en esta serie no hubo mortalidad perinatal, la experiencia clínica muestra el alto riesgo perinatal en estas pacientes. 3) De los tres parámetros estudiados comprobamos que los valores de péptido C - insulina, son los que fluctúan dentro de un rango menor, por lo cual su error standard es bajo. Esto permite suponer que el péptido C - insulina, es el más confiable en su aplicacion clínica para conocer el estado fetal y predecir la salud del recién nacido en las embarazadas diabéticas. 4) Con valores altos en liquído amniótico, ya sea de péptido C - insulina, insulina o glucosa, hay probabilidades que nazca un recién nacido de alto peso por edad gestacional (A.P.E.G.). 5) Exceptuando el A.P.E.G, la hiperbilirrubinemia del recién nacido, resulto ser la patología que guardó mayor relación con el aumento en la concentración de peptido C - insulina, insulina y glucosa. 6) Considerando el total del material se encontró una alta correlación entre péptido C - insulina e insulina. En diabéticas no pudimos corroborar esta correlación. 7) En las embarazadas con isoinmunización al factor Rh, no encontramos valores superiores a los normales en la concentración en líquido amniótico de los tres parámetros valorados. 8) De acuerdo a nuestros resultados y a los pocos estudios al respecto en la literatura mundial, la determinación de la concentración en líquido amniótico de péptido C - insulina, insulina y glucosa resulta de utilidad para el control del estado fetal en las embarazadas diabéticas. En algunos aspectos de estas investigaciones se necesita estudiar un número mayor de casos, antes de sacar conclusiones de aplicación clínica.

Efectos del dipropionato de betametasona inyectable en el asma bronquial cronica. / Effect of injectable betamethasone dipropionate in chronic bronchial asthma

Se administro dipropionato de betametasona por via intramuscular a 51 enfermos con asma bronquial cronica.Se lograron resultados buenos a excelentes em 96% de los enfermos. La accion terapeutica se inicio rapidamente y su duracion fue prolongada. Los efectos colaterales fueron leves y pasajeros, hubo tambien reduccion pasajera de las concentraciones de cortisol plasmatico matinales y en todos, excepto en uno de los enfermos, estos volvieron a sus limites normales hacia el final del ensayo