Séminaires de biomécanique le 05/07/2016

Notre laboratoire a le plaisir d’accueillir deux biomécaniciens de l’Université de Tel Aviv : Amit Gefen (éditeur du Journal Clinical Biomechanics et membre de l’editorial board du Journal of Biomechanics) et Daphne Weihs.

Dans ce cadre, ils feront un exposé mardi 05/07 de 14 à 15h, en salle R31 du Pavillon Taillefer. Vous trouverez ci-dessous les détails sur leurs exposés.

1) Amit Gefen, PhD
Professor in Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Israel

Title : Increasing the pressure on prevention : From ulcers to injuries
Abstract : Our understanding of the etiology of pressure ulcers is developing rapidly. The pressure ulcer society in the United States (www.npuap.org) just changed terms from "pressure ulcers" to "pressure injuries" and amended their classification system accordingly, which implies that the etiology is considerably affected by the environment of the patient (e.g. their support surface, medical equipment etc.) which could hence cause an injury to the tissues, as opposed to an ulcer which implies that the process evolves internally in the body. Indeed, the revised definition and classification system of the Americans now emphasizes device-related pressure injuries which are common, but not studied as much as the weight-bearing associated pressure injuries are. My talk will focus on these less studied medical device-related injuries, particularly in the pediatric population, and will show, from a biomechanical perspective, how computational modeling can be used to assess risks from a device and thereby contribute to a safer environment with regard to pressure injury prevention.

2) Daphne Weihs, daphnew@technion.ac.il
Faculty of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel http://weihs.net.technion.ac.il/

Title : The Effect of Sustained Static Tensile Strain and honey treatments on en mass Cell Migration Associated with Wound Healing
Abstract : We observe that radially stretching cell monolayers at a low level (3%) increases the rate at which they close a gap formed by in vitro injury. Wound healing has recently been treated topically by applying deformations at the wound site, e.g. by negative pressure wound therapy. However, the direct effect of deformations on cell migration during gap closure is still unknown. Thus, we have evaluated the effect of radially applied, sustained (static) tensile strain on the kinematics of en mass cell migration. Monolayers of murine fibroblasts were cultured on stretchable linear-elastic substrates that were subjected to different tensile strains, using a custom-designed 3D printed stretching apparatus. Following stretching, the monolayer was “wounded” at its center and the cell migration during gap closure was monitored and quantitatively evaluated. We observe a significant increase in gap-area normalized migration rates and reduction of gap closure time under stretching of 3%, relative to unstretched controls. The effect was reduced under 6% stretch. Interestingly, the initial gap area was linearly correlated with the maximum migration rates even for very small gaps, and especially under applied stretch. We also apply varying concentrations of natural honey to evaluate the direct effect of the treatment on the cell migration rates during gap closure. Thus we show that small deformations and various treatments applied to cell monolayers during gap closure enhance en mass cell migration associated with wound healing and can be used to fine-tune treatment protocols.

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