Differential Effect of Cobalt and Chromium Ions as Well as CoCr Particles on the Expression of Osteogenic Markers and Osteoblast Function.

The balance of bone formation and resorption is the result of a regulated crosstalk between osteoblasts, osteoclasts, and osteocytes. Inflammation, mechanical load, and external stimuli modulate this system. Exposure of bone cells to metal ions or wear particles are thought to cause osteolysis via activation of osteoclasts and inhibition of osteoblast activity. Co2+ ions have been shown to impair osteoblast function and the expression of the three transforming growth factor (TGF)-ß isoforms. The current study was performed to analyze how Co2+ and Cr3+ influence the expression, proliferation, and migration profile of osteoblast-like cells. The influence of Co2+, Cr3+, and CoCr particles on gene expression was analyzed using an osteogenesis PCR Array. The expression of different members of the TGF-ß signaling cascade were down-regulated by Co2+, as well as several TGF-ß regulated collagens, however, Cr3+ had no effect. CoCr particles partially affected similar genes as the Co2+treatment. Total collagen production of Co2+ treated osteoblasts was reduced, which can be explained by the reduced expression levels of various collagens. While proliferation of MG63 cells appears unaffected by Co2+, the migration capacity was impaired. Our data may improve the knowledge of changes in gene expression patterns, and the proliferation and migration effects caused by artificial materials.

Endoscopic Imaging Technology Today.

One of the most applied imaging methods in medicine is endoscopy. A highly specialized image modality has been developed since the first modern endoscope, the "Lichtleiter" of Bozzini was introduced in the early 19th century. Multiple medical disciplines use endoscopy for diagnostics or to visualize and support therapeutic procedures. Therefore, the shapes, functionalities, handling concepts, and the integrated and surrounding technology of endoscopic systems were adapted to meet these dedicated medical application requirements. This survey gives an overview of modern endoscopic technology's state of the art. Therefore, the portfolio of several manufacturers with commercially available products on the market was screened and summarized. Additionally, some trends for upcoming developments were collected.

Stiffness of meniscus tissue depends on tibio-femoral load and structural integrity of the meniscus root.

Development of meniscus replacements requires in-depth knowledge of the material properties and biomechanical behavior of the native meniscus. The compressive properties are of particular interest in this context, which are often assessed with indentation tests. However, those tests are usually done on isolated tissue specimens ex situ, which could have a significant impact on the results. It was, therefore, the goal of the study to assess the stiffness of the meniscus tissue in situ in porcine specimens and to compare it to that of artificial substitutes. Porcine knees (n = 8) were prepared such that the medial meniscus periphery was exposed and the knees could be mounted in a materials testing machine. The tissue stiffness was than measured on the meniscus periphery using a Shore-A durometer in (1) the unloaded knee, (2) with 500-N tibio-femoral compressive load, and (3) with 500-N tibio-femoral load and the posterior meniscus root detached. The stiffness of the meniscus tissue was significantly increased when tibio-femoral load was applied, while this effect was lost when the meniscus root was cut (average measurements on a 0-100 Shore-A durometer scale: group A, 33.8; group B, 58.4; and group C, 36.2). Polyurethane and collagen meniscus implants showed an inferior stiffness compared to the native meniscus. These findings might be relevant for the material choice in artificial meniscus replacements and the fixation of allografts. Biomechanical testing of isolated tissue specimens could underestimate the effective meniscus tissue stiffness compared to a physiological joint environment.