PRINCIPLES OF APPLIED BIOMECHANICS ON THE RACE WALKERS: IMPROVEMENT IN PERFORMANCE WITH A PLANTAR ORTHOSIS

When race walking it is essential to attain and maintain for a period of time the maximal speed with minimal expenditure of energy, in observance of the prescribed standards. To achieve this end, optimizing the physical carriage is indispensable. This may be done in two ways: I) by reducing those force component hat ace employed along directions of application that do no concur with the sense of progression, since they interfere with and disperse part of the energy; and 2) by increasing the vectorial components that have the same direction as the forward movement. The aim of our work was to verify the modifications that are induced by the use of plantar orthoses , as reflected by parameters of biomechanical performance on the race walker: Under standard reference conditions, we studied the kinematics and ground reaction of 10 highly-trained Athletes. With reference to report that confirmed previous study by us and other authors, we verified the modifications induced by the applications of special dynamic plantar orthoses. The ground reaction appeared to be optimized by the use of these orthoses through the following mechanisms: 1) a diminution of the sagittal force components that are opposed to the direction of movemen6 2) a diminution of the transverse edgewise components that are not useful to the progression, and 3) an increase in the reclamation of useful elastic energy stored by the functional unit, the 'musculo-skeletal footwear system”

Role of endothelin-1 in the migration of human olfactory gonadotropin-releasing hormone-secreting neuroblasts

FNC-B4 neuroblasts that express both neuronal and olfactory markers have been established and cloned. These cells express GnRH and both the endothelin-1 (ET-1) gene and protein and respond in a migratory manner to GnRH in a dose-dependent manner. Previous research has shown that FNC-B4 cells produce and respond to ET-1 by regulating the secretion of GnRH through endothelin type A receptors and by stimulating their proliferation through endothelin type B (ETB) receptors. In this study, we found that FNC-B4 cells are able to migrate in response to ET-1 through the involvement of ETB receptors. Combined immunohistochemical and biochemical analyses showed that ET-1 triggered actin cytoskeletal remodeling and a dose-dependent increase in migration (up to 6-fold). Whereas the ETB receptor antagonist (B-BQ788) blunted the ET-1-induced effects, the ETA receptor antagonist (A-BQ123) did not. Moreover, we observed that FNC-B4 cells were independently and selectively stimulated by ET-1 and GnRH. We suggest that ET-1, through ETB receptor activation, may be required to maintain an adequate proliferative stem cell pool in the developing olfactory epithelium and the subsequent commitment to GnRH neuronal migratory pattern. The coordinate interaction between ET receptors and GnRH receptor participates in the fully expressed GnRH-secreting neuron phenotype

A nanoscale fluorocarbon coating on PET improves the adhesion and growth of cultured coronary endothelial cells

Plasma deposition was applied to deposit smooth and nanostructured fluorocarbon coatings on polyethylene terephthalate substrates, with the aim to obtain surfaces with identical chemical composition but different roughness to improve the endothelialization process on PET surfaces. We found that increased roughness was associated with enhanced endothelial cell response, as shown by the ability of cells to grow and adhere to nanostructures. We also observed specific interaction of filopodia protruding from the cell membrane with individual nanostructures, leading to increased cell attachment, spreading and cell viability. Among the modified surfaces, one termed PET-tfl90 emerged as the one capable of best sustaining the formation of a confluent monolayer of endothelial cells. In conclusion, PET modified by nanostructured fluorocarbon film represents an improved graft material, over conventional PET, for endothelial cell adhesion and growth