FGF-2 signaling induces downregulation of TAZ protein in osteoblastic MC3T3-E1 cells.

Transcriptional coactivator with PDZ-binding motif (TAZ) protein is a coactivator of Runx2 and corepressor of PPARgamma. It also induces differentiation of mesenchymal cells into osteoblasts. In this study, we found that FGF-2, which inhibits bone mineralization and stimulates cell proliferation, reduced the TAZ protein expression level in osteoblast-like cells, MC3T3-E1.

Analysis for the major contributor of collagenase to the primary cleavage of type II collagens in cartilage degradation.

Degradation of type II collagen is a central process in cartilage destruction seen in osteoarthritis and rheumatoid arthritis. Primary cleavage of type II collagen at the collagenase site is rate-limiting and is, therefore, a critical step for its degradation. The major contributor to this cleavage was identified in three isozymes of collagenase in human cartilage.

Degree of mineralization-related collagen crosslinking in the femoral neck cancellous bone in cases of hip fracture and controls.

Based on the present definition of osteoporosis, both bone density and quality are important factors in the determination of bone strength. Collagen crosslinking is a determinant of bone quality. Cross-links can form enzymatically by the action of lysyl oxidase or non-enzymatically, resulting in advanced glycation end products.

Old rupture of the triceps tendon with unique pathology: a case report.

We report the case of a 23-year-old man who presented 4 years after a triceps tendon rupture. A cord-like tissue, palpable and visible at full elbow flexion, was found to sublux to the lateral aspect of the elbow. Repair of the tendon has been achieved utilizing an artificial polyester mesh to augment the repair and permit early mobilization of the elbow.

Tendon suspension sling arthroplasty for degenerative arthritis of the thumb trapeziometacarpal joint: long-term follow-up.

Twenty-two tendon suspension sling arthroplasties for thumb trapeziometacarpal osteoarthritis were reviewed. Age at operation ranged from 53 to 74 years (average, 65 years); 20 of the 22 patients were women. The average follow-up period was 101 months (range, 63-139 months).

The "ligamentization" process in human anterior cruciate ligament reconstruction with autogenous patellar and hamstring tendons: a biochemical study.

Background: There is little information documenting whether the phenomenon of "ligamentization," as proposed by Amiel, occurs in the human anterior cruciate ligament after clinically effective reconstruction. To clarify this point, we analyzed biochemical differences between the native anterior cruciate ligament; the patellar, semitendinosus, and gracilis tendons; and anterior cruciate ligaments reconstructed with autografts.

Study Design: Cohort study; Level of evidence, 2.

[Correlation between degree of mineralization and collagen cross-links as determinants of bone quality].

Little is known about the correlation between degree of mineralization and collagen properties (enzymatic and non-enzymatic cross-links) in bone. In the patients with femoral neck fracture, not only the mineral embrittlement but also the qualitative changes in collagen cross-links were observed in both low and high mineralized bone fractions. These results suggest that this trend towards an increased loss of collagen quality may have led to accelerated increase of fragility in osteoporosis.

Use of a biphasic graft constructed with chondrocytes overlying a beta-tricalcium phosphate block in the treatment of rabbit osteochondral defects.

To evaluate the ability of a biphasic construct to repair osteochondral defects in articular cartilage, plugs made of chondrocytes in collagen gel overlying a resorbable porous beta-tricalcium phosphate (TCP) block were implanted into defects in rabbit knees. The repair tissue was evaluated at 8, 12, and 30 weeks. Eight weeks after implantation of the biphasic construct, histologic examination showed hyaline-like cartilage formation that was positive for safranin O and type II collagen.

Solitary eosinophilic granuloma of the sternum.

We report a rare case of eosinophilic granuloma of the sternum in a 25-year-old woman, who presented with anterior chest pain and a tender mass over the sternum. Total-body bone scintigraphy and computed tomography scanning of the thorax revealed an isolated lytic lesion of the manubrium. An open biopsy showed the typical histologic appearance of an eosinophilic granuloma.

Radial head dislocation with acute plastic bowing of the ulna.

Five radial head dislocations with acute plastic bowing of the ulna in patients aged 6-12 years were reviewed. Closed reduction was successful in two, and open reduction was required in three patients in whom treatment was started more than 2 weeks after injury. In one child who presented 2 months after injury, realignment by osteotomy of the ulna as well as open reduction of the radial head was necessary.

No mixing of granulocytes and other lymphocytes in the inflamed joints of parabiosis mice with collagen-induced arthritis: possible in situ generation.

Collagen-induced arthritis was evoked by an injection of lipopolysaccharide and anti-type II collagen antibody in mice. In parallel with the onset of arthritis, granulocytes with large light scatter and a Mac-1(+) Gr-1(+) phenotype expanded in the joints of these mice. Lymphocytes with a CD3(-) B220(+) phenotype (i.

Expression analysis of three isoforms of hyaluronan synthase and hyaluronidase in the synovium of knees in osteoarthritis and rheumatoid arthritis by quantitative real-time reverse transcriptase polymerase chain reaction.

Hyaluronan is a major molecule in joint fluid and plays a crucial role in joint motion and the maintenance of joint homeostasis. The concentration and average molecular weight of hyaluronan in the joint fluids are reduced in osteoarthritis and rheumatoid arthritis. To elucidate the underlying mechanism, we analyzed the message expression of three isoforms of hyaluronan synthase and hyaluronidase from knee synovium, using real-time reverse transcriptase polymerase chain reaction.

Intensity-related differences in collagen post-translational modification in MC3T3-E1 osteoblasts after exposure to low- and high-intensity pulsed ultrasound.

Low-intensity pulsed ultrasound (LIPUS) has distinct effects on biologic mineralization at intensities of <100 mW/cm2. Intensity-dependent differences in the pattern of accelerated mineralization may be due to different alterations in regulation of collagenous matrix formation. However, little is known about the influence of LIPUS on collagen metabolism in the context of mineralization processes.

Bone formation and bioresorption after implantation of injectable beta-tricalcium phosphate granules-hyaluronate complex in rabbit bone defects.

The objective of this study was to evaluate the effects of a complex of beta-tricalcium phosphate (beta-TCP) granules and 3.5% hyaluronate (beta-TCP granules-HY complex) compared with a beta-TCP block, in terms of osteoconductivity and biodegradability, to determine whether this complex would be a good candidate for bone void filler. Both materials were implanted into cavities drilled in rabbit femoral condyles.

Sequence-specific silencing of MT1-MMP expression suppresses tumor cell migration and invasion: importance of MT1-MMP as a therapeutic target for invasive tumors.

Membrane-type 1 matrix metalloproteinase (MT1-MMP/MMP-14) has been believed a key enzyme in tumor invasion, because it is expressed in a variety of malignant human tumors, and overexpression of the enzyme enhances the ability of cellular invasiveness. However, it has not necessarily been clarified whether the endogenously expressed MT1-MMP in human tumors plays a critical role in their invasiveness. We used RNA silencing technology to downregulate the endogenous MT1-MMP expression in human tumor cells (fibrosarcoma HT1080 and gastric carcinoma MKN-28 cell lines), and evaluated the effect on the invasion of a reconstituted basement membrane (Matrigel).

In vivo administration of 1,25-dihydroxyvitamin D3 suppresses the expression of RANKL mRNA in bone of thyroparathyroidectomized rats constantly infused with PTH.

It is known that pharmacological or toxic doses of vitamin D induce bone resorption both in vivo and in vitro, whereas physiological doses of the vitamin have a protective effect on bone in vivo. To investigate the discrepancies of the dose-dependent effect of vitamin D on bone resorption, we examined the in vivo effect of 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] on the expression of the receptor activator of nuclear factor-kappaB (NF-kappaB) ligand (RANKL) and osteoprotegerin (OPG) mRNAs in bone of thyroparathyroidectomized (TPTX) rats infused with or without parathyroid hormone (PTH). Continuous infusion of 50 ng/h of PTH greatly increased the expression of RANKL mRNA in bone of TPTX rats.

Effect of hyper- and microgravity on collagen post-translational controls of MC3T3-E1 osteoblasts.

Unlabelled: We attempted to study the effects of microgravity (by clinostat) and hypergravity (using centrifugation) on collagen metabolism using murine MC3T3-E1 osteoblasts, especially focusing on collagen cross-link formation. We found that altered gravitational load affected the post-translational modification of collagen, particularly the collagen maturation pathway, through altered expression of enzymes involved in cross-link formation.

Introduction: Gravitational loading plays important roles in the stimulation of differentiated osteoblast function and in the maintenance of skeletal tissues, whereas microgravity seems to result in osteopenia caused by impaired osteoblast differentiation.

Autoimmune reaction to type II collagen and cartilage degeneration in MRL/Mp- lpr/lpr mouse.

The early phase of cartilage degeneration was immunohistochemically examined in order to clarify the importance of autoimmune reaction against type II collagen in MRL/Mp- lpr/lpr (MRL/ l) mouse in an experimental model of rheumatoid arthritis (RA). Anti-type II collagen antibodies were detectable in 3-week-old mice and preceded the appearance of rheumatoid factors. Furthermore, mesenchymal cells and tartrate-resistant acid phosphatase-positive cells began to accumulate remarkably in the periphysis, a fibrochondro-osseous area in the bone marrow vicinity.

Vitamin D and bone.

It is now well established that supraphysiological doses of 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)] stimulate bone resorption. Recent studies have established that osteoblasts/stromal cells express receptor activator of NF-kappaB ligand (RANKL) in response to several bone-resorbing factors including 1alpha,25(OH)(2)D(3) to support osteoclast differentiation from their precursors. Osteoclast precursors which express receptor activator of NF-kappaB (RANK) recognize RANKL through cell-to-cell interaction with osteoblasts/stromal cells, and differentiate into osteoclasts in the presence of macrophage-colony stimulating factor (M-CSF).