RESUMEN
We present a case of early retrieval of an Oxinium femoral head and corresponding polyethylene liner where there was significant surface damage to the head and polyethylene. The implants were retrieved at the time of revision surgery to correct leg-length discrepancy just 48 hours after the primary hip replacement. Appropriate analysis of the retrieved femoral head demonstrated loss of the Oxinium layer with exposure of the underlying substrate and transfer of titanium from the acetabular shell at the time of a reduction of the index total hip replacement. In addition, the level of damage to the polyethylene was extensive despite only 48 hours in situ. The purpose of this report is to highlight the care that is required at the time of reduction, especially with these hard femoral counter-faces such as Oxinium. To our knowledge, the damage occurring at the time of reduction has not been previously reported following the retrieval of an otherwise well-functioning hip replacement.
Asunto(s)
Artroplastia de Reemplazo de Cadera/efectos adversos , Prótesis de Cadera , Falla de Prótesis , Análisis de Falla de Equipo/métodos , Femenino , Cabeza Femoral/cirugía , Humanos , Persona de Mediana Edad , Polietileno , Diseño de Prótesis , ReoperaciónRESUMEN
The influence of copper was assessed on wild and tolerant strains of the lichen photobiont Trebouxia erici and shown to have multiple toxic effects. Addition of 4 mM copper chloride into Trebouxia media reduced growth rates of the wild type to less than 1% of control levels. It also injured cell membranes, inhibited dehydrogenase activity, altered pigment composition, and reduced activity of photosystem II. Membrane damage was assessed through measuring electrical conductivity and potassium content, dehydrogenase activity by degree of conversion of 2,3,5-triphenyl tetrazolium chloride to red triphenylformazan, and functioning of PS II by chlorophyll a fluorescence. In respect to most parameters the tolerant strain was usually less affected by copper than the wild strain and, in some cases, not at all. We demonstrated by inductively coupled plasma atomic emission spectrometry and energy-dispersive X-ray microanalysis that enriched copper in the medium resulted in increased uptake by both wild and tolerant photobiont cells, but extracellular concentrations were significantly higher in the tolerant strain. This suggested that, at least in vitro, extracellular deposition was a mechanism of copper tolerance.
Asunto(s)
Chlorophyta/efectos de los fármacos , Chlorophyta/fisiología , Cobre/toxicidad , Contaminantes Ambientales/toxicidad , Líquenes/crecimiento & desarrollo , Adaptación Fisiológica , SimbiosisRESUMEN
This study investigated the bonding mechanisms of glass-ionomer cement to dentin. The approaches included mechanical determination of bond strengths, analysis of surface morphology by means of scanning electron microscopy (SEM) and confocal microscopy, and measurement of chemical changes of fracture bond sites by means of x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). The highest bond strengths were obtained with light-cured glass-ionomer cement. SEM and confocal images showed evidence of mechanical interlocking of cement in dentinal tubules. SIMS depth profiles confirmed the ion-exchange process between the light-cured glass-ionomer cement and the dentin surface. From corresponding XPS results, it was clear that the adhesion characteristics were significantly affected by light-curing and the chemical structure of the polymer.