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  • 1
    Electronic Resource
    Electronic Resource
    Induction of Interleukin-6 Release in Human Osteoblast-Like Cells Exposed to Titanium Particles In Vitro (2000)
    Springer
    Calcified tissue international 67 (2000), S. 151-155 
    Details
    ISSN: 1432-0827
    Keywords: Key words: Interleukin-6 — MG-63 cells — Titanium particles — Signal transduction — Transcription factor.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. Orthopaedic wear debris induces release of bone-resorbing factors from macrophages and fibroblasts. However, the extent to which elemental metallic particles induce bone cells to express factors contributing to implant loosening remains unclear. This study showed that exposure of MG-63 osteoblast-like cells to titanium particles at a concentration of 0.30% v/v resulted in a 15-fold increase in IL-6 release into the culture medium after 24 hours, when compared with cells without particles. Northern blots revealed that exposure of MG-63 cells to titanium particles at a concentration of 0.30% v/v for 24 hours increased IL-6 mRNA signal levels by 9.6-fold, when compared with control cultures. Pretreatment of MG-63 cells with cytochalasin B prevented the particle-induced increase of IL-6 expression but did not alter the basal level of IL-6 release from cells cultured in the absence of particles. The protein kinase C inhibitor, H7, and the serine/threonine kinase inhibitor, genistein, abolished the particle-induced increase in IL-6 release at a concentration of 100 μM for each compound. In contrast, an inhibitor of protein kinase A, HA1004, had no effect on the particle-induced increase in IL-6 release. The transcription factors, nuclear factor IL-6 and nuclear factor kappa B, translocated into the nucleus within 1 hour of particle exposure. This study showed that osteoblast-like cells respond to titanium particles through increased expression of the proinflammatory cytokine, IL-6, in a process requiring phagocytosis and intracellular signaling pathways. These results suggest that osteoblasts play a direct role in implant loosening because of localized release of soluble mediators such as interleukin-6.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00223001125
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  • 2
    Electronic Resource
    Electronic Resource
    In vivo and in vitro comparative studies of animal articular surfaces (1975)
    Springer
    Annals of biomedical engineering 3 (1975), S. 100-110 
    Details
    ISSN: 1573-9686
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract The contours in the articular surfaces of rabbit and canine knee joints were measured in vivo and in vitro using the scanning electron microscope (SEM), replication, and light-microscopy techniques. Using the light microscope, patterns of highlights of the order 10 μm were observed when the living joint-surfaces were exposed. Replicas were made of these surface contours using Xantopren, a light-bodied dental silicone impression-material. More than 50% of the replicas were discarded because of defects. In the SEM, a crazing phenomenom was sometimes evident on the replicated surfaces which may have been attributable to distortion of the silicone medium, possibly in vacuo. The interpretable replicas from the living joint-surfaces contained 7 to 20 μm diameter humps that varied from 0.5 to 2.5 μm high. These corresponded to the patterns of highlights seen with the light microscope at surgery. Examination of the replicas taken in vitro and direct examination of the cartilage in the SEM revealed comparable data. The living articular-cartilage contours, therefore, appear to correspond to those previously identified in vitro. We emphasize that although these values give some indication of the anticipated in vivo contours, the actual contours in a load-carrying situation may differ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00000007
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  • 3
    Electronic Resource
    Electronic Resource
    Preparation and characterization of wear debris of orthopedic materials for biocompatibility studies (1976)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 10 (1976), S. 653-670 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: In order to test the biocompatibility of wear debris of orthopedic materials, a method has been developed to produce artificial debris of stainless steel, cobalt-chromium alloy, and high-density polyethylene. In this process, called the accelerated rubbing process, two cylindrical blocks of the same alloy were held under normal pressure in triply distilled water. One block remained stationary while the other rotated at ∼4000 rpm. The water with the metal debris was recirculated between the rubbing surfaces. To prepare debris from polyethylene, a stainless steel block was rubbed over a polyethylene block submersed in liquid nitrogen.The shape of the metal debris was granular, whereas the polyethylene debris had a shted-like shape. The size distributions were determined from scanning electron micrographs, and it was found that the particles of the metal debris (stainless steel or cobalt-chrome alloy) ranged in sizes from 0.1-10 μ with 75% of all particles 〈2 μ in diameter. The size of polyethylene debris, expressed as the volume of an ellipsoid, ranged from 10-20,000 μ3 with 45% of all particles in the range of 400-2500 μ3.The x-ray diffraction pattern revealed that the debris of stainless steel consisted primarily of the face-centered cubic (fcc) alloy with small amounts of body-centered cubic (bcc) alloy and Fe3O4, whereas the cobalt-chrome debris consisted of the fcc alloy with a small amount of Cr2O3.The structure of the polyethylene debris was quite similar to that of the solid sample used in its preparation. The percent crystallinity Pc and the size of the crystalline regions D were slightly smaller in the debris than in the solid sample, i.e., Pc = 52 and 55%, D = 90 and 130 Å, in the debris and the solid, respectively.To test the suitability of the artificial debris for biocompatibility studies, stainless steel debris was implanted into knees of adult female New Zealand rabbits. Bacterial challenge studies indicated prolongation, but not increased susceptibility to infection.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820100503
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