N Hallab

..Thus, LTT (provided by laboratories fully disclosing testing methods) may be an additional tool in the armamentarium of physicians...

..4 mM and Co at 0.8 mM on osteoblasts). Thus, soluble Co and V released from Co- and Ti-based alloys, respectively, could be implicated as the most likely to mediate cell toxicity in the periprosthetic milieu...

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..Determination of specific protein carriers of metal degradation products is an essential component in the assessment of the long-term biological affects of total joint replacement devices...

..This elevated incidence and averaged level of lymphocyte reactivity supports a metal-specific adaptive immune response and suggests involvement in the pathogenesis of poor implant performance, e.g. aseptic osteolysis...

..The high incidence of lymphocyte reactivity and activation indicate that more complex than initially hypothesized immune responses may contribute to the etiology of debris-induced osteolysis in metal-sensitive individuals...

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..Knowledge gained through the clinical history of total joint replacement materials combined with the current promise of new biomaterials provides improved guidelines for biomaterial selection in total disc arthroplasty...

..Tissue explant, animal, and cell culture studies have revealed the complexity of cellular reactivity involved in aseptic particle-induced osteolysis...

..Identification of metal alloy-dependent biofilm compositions and dissolution products provides the basis for understanding the bioavailability and bioreactivity of these implant alloys and their degradation products...

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..This response was greatest when the metals were complexed with high molecular weight proteins, and with metal-protein complexes formed from Co-Cr-Mo alloy degradation...

..It is currently unclear whether metal sensitivity is a contributing factor to implant failure...

..Thus, surface energy may be a more important determinant of cell adhesion and proliferation, and may be more useful than surface roughness for directing cell adhesion and cell colonization onto engineered tissue scaffoldings...

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..The long-term success of total disc arthroplasty may well depend, at least in part, on the ability to minimize implant debris generation and the subsequent local and systemic response...

..In addition, the biologic response to debris generated from alternate bearings is not fully elucidated and is related not only to particle number, but also to particle size, shape, composition, and surface area...

..This suggests metal-induced up-regulation of costimulatory molecules and proinflammatory cytokine production is necessary to induce lymphocyte activation/proliferation to metal implant debris...

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..Therefore, our results suggest that osteocytes play a role in particle-induced inflammation and bone resorption following total joint arthroplasty by inducing pro-inflammatory cytokines and inducing osteocyte apoptosis...

..This study examines the time course and clinical relevance of changes in prostaglandin E2 and cytokines in cerebrospinal fluid, local tissue (surgical site), and circulating blood during and after total hip replacement...

..2 N/mm2) and welded (8.3 N/mm2) groups (P < .05), but no differences were observed between the knotted and welded groups. Although some histologic changes were noted, none was considered to be significant to distinguish either group...

..Nonetheless, metal concentration analysis remains a powerful research tool in the evaluation of metal-on-metal hip arthroplasty systems...

..About 50% of the variance in implant fixation strength was explained by a regression model involving both bone-implant contact and peri-implant bone volume...

..e., <0.05 mM). All the metals tested induced T-cell apoptosis at a lower dose than that required to affect DNA damage or toxicity, implying that soluble metals released from implants may not be preferentially genotoxic to lymphocytes...

..These results represent the first direct link between in vivo metal exposure and lymphocyte reactivity. Whether this lymphocyte reactivity to metal debris is etiologically linked to poor implant performance remains uncertain...

..Additionally, variable immunologic responses induced by implant degradation products (i.e. lymphocyte response to metal ions and monocyte/macrophage response to particulate debris) will be correlated with the development of osteolysis ..