Calcineurin modulates the catabolic and anabolic activity of chondrocytes and participates in the progression of experimental osteoarthritis.

Objective: To determine whether intracellular calcineurin (Cn), a calcium-activated phosphatase, regulates the anabolic and catabolic activities of chondrocytes, and is a potential target in the treatment of osteoarthritis (OA).

Methods: CnA expression was examined in cartilage tissue samples and cultured chondrocytes from OA patients, using immunohistochemistry and Western blot analysis, respectively. Concentrations of matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases 1 (TIMP-1) in the culture supernatants were determined using enzyme-linked immunosorbent assay.

Calcineurin is expressed and plays a critical role in inflammatory arthritis.

Calcineurin is a calcium-activated phosphatase to mediate lymphocyte activation and neuron signaling, but its role in inflammatory arthritis remains largely unknown. In this study, we demonstrate that calcineurin was highly expressed in the lining layer, infiltrating leukocytes, and endothelial cells of rheumatoid synovium. The basal expression levels of calcineurin were higher in the cultured synoviocytes of rheumatoid arthritis patients than those of osteoarthritis patients.

Acute pachymeningitis mimicking subdural hematoma in a patient with polyarteritis nodosa.

Pachymeningitis is a very rare neurologic manifestation of polyarteritis nodosa (PAN). This report describes a case of acute pachymeningitis that was, initially, misdiagnosed as subdural hematoma on the brain CT of a patient with PAN. A 45-year-old man, who had been diagnosed as having PAN 6 months previously, came back to the emergency room with complaints of sudden headache, nausea, vomiting, and diplopia for 3 days before his hospital admission.