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E. Chassot

Publications and source records attributed to E. Chassot.

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Contamination by metallic elements released from joint prostheses

When a metallic implant is in contact with human tissues, the organism reacts and a corrosion process starts. Consequently, we might observe liberation of metallic debris and wear. Our purpose is to measure the contamination and the migration of these metallic elements in the surrounding tissues of the implant. Two types of samples have been studied. First type is sample taken on post-mortem tissues around prostheses to study contamination gradients. Second type is sample taken on pathologic joints on periprosthetic capsular tissues in surgical conditions. These allow estimating contamination degree. The experiments were made on a Van de Graaff accelerator located at CERI (Centre d'Etude et de Recherche par Irradiation, Orléans, France). We measure elemental concentrations resulting from the contamination of the surface of each sample. Results are analysed in function of the pathology and the type of implants. According to the pathology and the location of the sampling, these measurements show a very heterogeneous contamination by metallic elements under particles and/or ionic species which can migrate through soft tissues by various mechanisms

physics.bio-ph

Atomic transfers between implanted bioceramics and tissues in orthopaedics surgery

We study transfers of ions and debris from bioceramics implanted in bone sites. A contamination of surrounding tissues may play a major role in aseptic loosening of the implant. For these reasons, bioceramics require studies of biocompatibility and biofunctionality . So, in addition to in vitro studies of bioceramics, it is essential to implant them in vivo to know body reactions. We measured the concentration of mineral elements at different time intervals after implantation over a whole cross-section. We found a discontinuity of the mineral elements (Ca, P, Sr, Zn, Fe) at the interface between the implant and the receiver. The osseous attack is not global but, on the contrary, centripetal. Moreover, the fit of the concentration time course indicates that the kinetics of ossification is different for each atomic element and characterizes a distinct biological phenomenon

physics.bio-ph