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Background Many histological, mechanical, and clinical studies have been performed on the medial meniscus posterior root attachment, as it often tears in patients with osteoarthritic knee. Medial meniscal root repair is recommended in clinical situations; however, to date, no studies have examined the differences between meniscal root and horn cells. The aim of this study was, therefore, to investigate the morphology, reaction to cyclic tensile strain, and gene expression levels of medial meniscal root and horn cells. Methods Meniscal samples were obtained from the medial knee compartments of 10 patients with osteoarthritis who underwent total knee arthroplasty. Root and horn cells were cultured in Dulbecco's modified Eagle's medium without enzymes. The morphology, distribution, and proliferation of medial meniscal root and horn cells, as well as the gene and protein expression levels of Sry-type HMG box 9 and type II collagen, were determined after cyclic tensile strain treatment. Results Horn cells had a triangular morphology, whereas root cells were fibroblast-like. The number of horn cells positive for Sry-type HMG box 9 and type II collagen was considerably higher than that of root cells. Although root and horn cells showed similar levels of proliferation after 48, 72, or 96 h of culture, more horn cells than root cells were lost following a 2-h treatment with 5% and 10% cyclic tensile. Sry-type HMG box 9 and α1(II) collagen mRNA expression levels were significantly enhanced in both cells after 2- and 4-h cyclic tensile strain (5%) treatment. Conclusions Medial meniscal root and horn cells have distinct morphologies, reactions to mechanical stress, and cellular phenotypes. Our results suggest that physiological tensile strain is important to activate extracellular matrix production in horn cells.

A stepped-diameter insulator source cavity is employed to a radiofrequency (RF) plasma source for development of a sputtering reactor, where an inner diameter near the open source exit is enlarged compared with the upstream diameter and convergent-divergent magnetic field is applied near the source exit to inhibit the plasma loss to the wall by separating the plasma from the wall. Furthermore argon gas is introduced at the interface between the different diameter regions; a high plasma density of ∼5 × 1017 m−3 can be obtained at ∼50 mm downstream of the source exit for an RF power of about 100 W. To enhance the sputtering performance, a permanent magnet is installed behind the target located downstream of the source and a target current can be increased. The results on the plasma density and a deposition rate of Cu film on a substrate are compared for different source cavities and gas injection locations, which confirm the validity of the stepped-diameter source cavity on the performance improvement of the sputtering reactor.

A multi-target plasma sputtering tool is developed for a recently progressed new concept of a semiconductor fab system called ‘Minimal Fab’. A frequency-tuning compact helicon plasma source is attached on the side wall of the compact vacuum chamber and the plasma is transported along curved magnetic field lines to a target surface, which is mounted on a rotational target holder and negatively biased by a dc power supply. The target material is sputtered by the ions accelerated by the sheath potential drop and deposited on the substrate facing the target. The target material can be changed by rotating the holder; thereby the multi-layered metallic film can be formed in the single chamber. Substrate heating induced by secondary electrons emitted from the target surface and accelerated by the sheath is successfully inhibited by a magnetic filter near the substrate. The performance of the sputtering reactor designed as a laboratory model is shown here. The sputtering reactor and all of the components required for the sputtering tool are successfully contained within a compact frame of Minimal Fab (29.5 cm in width, 45 cm in depth, and 144 cm in height) via the development of the compact reactor, especially the compact rf plasma source.

Objective: To investigate the inhibitory effects and the regulatory mechanisms of histone deacetylase (HDAC) inhibitors on mechanical stress-induced gene expression of runt-related transcription factor (RUNX)-2 and a disintegrin and metalloproteinase with thrombospondin motif (ADAMTS)-5 in human chondrocytes. Methods: Human chondrocytes were seeded in stretch chambers at a concentration of 5 x 10(4) cells/chamber. Cells were pre-incubated with or without HDAC inhibitors (MS-275 or trichostatin A; TSA) for 12 h, followed by uniaxial cyclic tensile strain (CTS) (0.5 Hz, 10% elongation), which was applied for 30 min using the ST-140-10 system (STREX, Osaka, Japan). Total RNA was extracted and the expression of RUNX-2, ADAMTS-5, matrix metalloproteinase (MMP)-3, and MMP-13 at the mRNA and protein levels were examined by real-time polymerase chain reaction (PCR) and immunocytochemistry, respectively. The activation of diverse mitogen-activated protein kinase (MAPK) pathways with or without HDAC inhibitors during CTS was examined by western blotting. Results: HDAC inhibitors (TSA: 10 nM, MS-275: 100 nM) suppressed CTS-induced expression of RUNX-2, ADAMTS-5, and MMP-3 at both the mRNA and protein levels within 1 h. CTS-induced activation of p38 MAPK (p38), extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (INK) MAPKs was downregulated by both HDAC inhibitors. Conclusion: The CTS-induced expression of RUNX-2 and ADAMTS-5 was suppressed by HDAC inhibitors via the inhibition of the MAPK pathway activation in human chondrocytes. The results of the current study suggested a novel therapeutic role for HDAC inhibitors against degenerative joint disease such as osteoarthritis.

Summary Objective To investigate the mechanism of mechanical stress-induced expression and regulation of aggrecanases and examine the role of runt-related transcription factor 2 (RUNX-2) in chondrocyte-like cells. Methods SW1353 cells were seeded onto stretch chambers at a concentration of 5×10 4 cells/chamber, and a uni-axial cyclic tensile strain (CTS) (0.5Hz, 10% stretch) was applied for 30min. Total RNA was extracted, reverse transcribed, and analyzed by polymerase chain reaction (PCR) and real-time PCR. RUNX-2 overexpression and small interfering RNA (siRNA) targeting RUNX-2 were used to investigate the role of RUNX-2 in CTS-induced gene expression. The involvement of diverse mitogen-activated protein kinase (MAPK) pathways in the activation of RUNX-2, MMP-13 and ADAMTS-5 during CTS was examined by Western blotting. Results CTS induced expression of RUNX-2 , MMP-13 , ADAMTS-4 , -5 , and -9 . Overexpression of RUNX-2 up-regulated expression of MMP-13 and ADAMTS-5 , whereas RUNX-2 siRNA resulted in significant down-regulation of mechanically-induced MMP-13 and ADAMTS-5 expression. CTS induced activation of p38 MAPK, and CTS induction of RUNX-2 , MMP-13 and ADAMTS-5 mRNA was down-regulated by the selective p38 MAPK inhibitor SB203580 but not by the p44/42 MAPK inhibitor U0126, or the JNK MAPK inhibitor JNK inhibitor II. Conclusions RUNX-2 might have a role as a key downstream mediator of p38's ability to regulate mechanical stress-induced MMP-13 and ADAMTS-5 expression.

Caracteristiques d'oxydation et reduction sur les complexes Pr n O 24 − 2 au-dessous de 523 K