Rheumatoid arthritis lung disease. Determinants of radiographic and physiologic abnormalities.

Objective: To determine the prevalence and important clinical predictors of radiographic and physiologic abnormalities indicative of rheumatoid arthritis interstitial lung disease (RA-ILD).

Methods: An unselected cohort of patients with a confirmed diagnosis of RA and known lung disease were identified (n = 336) and evaluated for RA disease activity and severity. Outcomes included abnormalities determined by the pulmonary function tests of forced vital capacity (FVC) and diffusion capacity for carbon monoxide (DLco), and/or chest radiographic findings of interstitial infiltrates.

Methotrexate patient education: a quality improvement study.

Objective: To determine patients' knowledge of the safe use and toxicity of methotrexate (MTX) and to define educational interventions implemented by a rheumatology nurse that improved patients' understanding of MTX therapy.

Methods: One hundred eighty-three patients from a university-based rheumatology clinic who were taking MTX completed an initial knowledge questionnaire concerning the proper use and possible toxicity of MTX. Following completion, a nurse reviewed the correct answers with each patient and provided written information on MTX.

Adenosine triphosphate levels in human plasma.

Objective: To quantify extracellular adenosine triphosphate (ATP) levels in human platelet-poor plasma as a potential source of synovial fluid ATP, and to determine variables affecting these levels.

Methods: ATP was measured by the specific luciferase method; platelet beta thromboglobulin was determined by radioimmunoassay. The effects of fasting, feeding, venipuncture, and muscular exercise were determined by serial venipuncture in healthy subjects.

Synovial fluid and plasma levels of cartilage matrix glycoprotein in arthritis.

As cartilage matrix glycoprotein (CMGP) is a prominent matrix constituent, we analyzed the relationship of levels in plasma (CMGPP) and synovial fluid (CMGPS) to each other, to clinical diagnosis, and to degree of radiographic cartilage degeneration. CMGP was measured in matched synovial fluid and plasma specimens from 67 patients with various forms of arthritis using an ELISA technique. CMGPS consistently exceeded CMGPP, CMGPP levels correlated significantly with CMGPS levels, and CMGP retention in joint fluid, as calculated by the ratio CMGPS: CMGPP, was significantly higher in patients whose synovial fluids contain basic calcium phosphate crystals.

Articular cartilage vesicles generate calcium pyrophosphate dihydrate-like crystals in vitro.

Objective: To identify the morphology of a mineral-forming of adult porcine hyaline articular cartilage digest and characterize the mineral it forms.

Methods: Electron microscopy, Fourier transform infrared (FTIR) spectroscopy, x-ray microanalysis, compensated polarized light microscopy, and biochemical studies including 14C-labeled UDPG pyrophosphohydrolase radiometric assay.

Results: This fraction of articular cartilage digest contained membrane-limited vesicles resembling growth plate cartilage matrix vesicles and formed mineral after only 24 hours in physiologic salt solution containing 1 mM ATP: The mineral contained inorganic pyrophosphate, 95% of which derived from ATP, and phosphate, 93% of which derived from inorganic phosphate in the medium.