[A Case of Retro-Odontoid Pseudotumor in a Very Elderly Individual].

Retro-odontoid pseudotumors are mainly caused by aging or rheumatoid arthritis. We treated a very elderly patient with retro-odontoid pseudotumor. A 92-year-old man was admitted with the chief complaints of difficulty walking and progressive numbness in the right upper and lower extremities.

Lidocaine induces ROCK-dependent membrane blebbing and subsequent cell death in rabbit articular chondrocytes.

Local anesthetics are administered intraarticularly for pain control in orthopedic clinics and surgeries. Although previous studies have shown that local anesthetics can be toxic to chondrocytes, the underlying cellular mechanisms remain unclear. The present study investigates acute cellular responses associated with lidocaine-induced toxicity to articular chondrocytes.

Extracellular and intracellular mechanisms of mechanotransduction in three-dimensionally embedded rat chondrocytes.

Purpose: Articular cartilage homeostasis involves modulation of chondrocyte matrix synthesis in response to mechanical stress (MS). We studied extracellular and intracellular mechanotransduction pathways mediating this response.

Methods: We first confirmed rapid up-regulation of the putative chondro-protective cytokine, interleukin (IL)-4, as an immediate response to MS.

Improved quality of cartilage repair by bone marrow mesenchymal stem cells for treatment of an osteochondral defect in a cynomolgus macaque model.

Background And Purpose: Integration of repaired cartilage with surrounding native cartilage is a major challenge for successful tissue-engineering strategies of cartilage repair. We investigated whether incorporation of mesenchymal stem cells (MSCs) into the collagen scaffold improves integration and repair of cartilage defects in a cynomolgus macaque model.

Methods: Cynomolgus macaque bone marrow-derived MSCs were isolated and incorporated into type-I collagen gel.

The COX-2 selective blocker etodolac inhibits TNFα-induced apoptosis in isolated rabbit articular chondrocytes.

Chondrocyte apoptosis contributes to the disruption of cartilage integrity in osteoarthritis (OA). Recently, we reported that activation of volume-sensitive Cl- current (ICl,vol) mediates cell shrinkage, triggering apoptosis in rabbit articular chondrocytes. A cyclooxygenase (COX) blocker is frequently used for the treatment of OA.

17β-Oestradiol inhibits doxorubicin-induced apoptosis via block of the volume-sensitive Cl(-) current in rabbit articular chondrocytes.

BACKGROUND AND PURPOSE Chondrocyte apoptosis contributes to disruption of cartilage integrity in osteoarthritis. Recent evidence suggested that the volume-sensitive organic osmolyte/anion channel [volume-sensitive (outwardly rectifying) Cl(-) current (I(Cl,vol) )] plays a functional role in the development of cell shrinkage associated with apoptosis (apoptotic volume decrease) in several cell types. In this study, we investigated the cellular effects of 17β-oestradiol on doxorubicin-induced apoptotic responses in rabbit articular chondrocytes.

Regulatory role of tyrosine phosphorylation in the swelling-activated chloride current in isolated rabbit articular chondrocytes.

Articular chondrocytes are exposed in vivo to the continually changing osmotic environment and thus require volume regulatory mechanisms. The present study was designed to investigate (i) the functional role of the swelling-activated Cl(-) current (I(Cl,swell)) in the regulatory volume decrease (RVD) and (ii) the regulatory role of tyrosine phosphorylation in I(Cl,swell), in isolated rabbit articular chondrocytes. Whole-cell membrane currents were recorded from chondrocytes in isosmotic, hyposmotic and hyperosmotic external solutions under conditions where Na(+), K(+) and Ca(2+) currents were minimized.

Swelling-activated Cl(-) current in isolated rabbit articular chondrocytes: inhibition by arachidonic Acid.

Articular chondrocytes play an important role in maintaining the structure and function of the cartilage in synovial joints, which is closely influenced by mechanical or osmotic stress. In the present study, isolated rabbit articular chondrocytes were examined during hyposmotic stress using the whole-cell patch-clamp method. When exposed to hyposmotic external solutions (approximately 5% or 32% decrease in osmolarity), isolated rabbit articular chondrocytes exhibited hyposmotic cell swelling, accompanied by the activation of the swelling-activated Cl(-) current (I(Cl,swell)).

Extension of lumbar spine infection into osteoarthritic hip through psoas abscess.

We present a case of pyogenic lumbar discitis and septic hip arthritis, accompanied by a psoas abscess and pyogenic iliopsoas bursitis, for which the correct diagnosis was delayed. The patho-mechanism was speculated to be initial hematogenous infection in the lumbar spine that spread along the psoas muscle as a psoas abscess and then extended into the hip joint via the iliopsoas bursa. For an early correct diagnosis, clinicians should be aware that the lumbar spine and hip joint regions communicate through the psoas muscle space and iliopsoas bursa, making it possible for infection to spread.