Transforming growth factor ß (TGF ß) is a multifunctional growth regulator with diverse biological effects, including promotion and inhibition of fibroblastic and epithelial cell growth, respectively (1, 2), chemotaxis of dermal fibroblasts and monocytes (3, 4), facilitation of extracellular matrix remodeling by fibroblastic cells (5-7), and effects on proliferation and function of T and B lymphocytes (8-10). These cellular responses appear pertinent to development and/or maintenance ofthe synovial panmus in inflammatory arthritis. Furthermore, subcutaneous injection of purified TGFP into newborn mice results in a multicellular response over 48-72 h (11), which is histologically similar to the synovial panmus seen in rheumatoid arthritis (RA). These findings led us to examine synovial effusions for the presence of TGFß.Volume 169 January 1989 291-296
Materials and Methods
Brief Definitive ReportSynovial Fluids . Synovial fluids from the knees of 16 patients seen in the Vanderbilt University Rheumatology Clinic were collected by needle aspiration into heparin-free plastic syringes . Diagnoses determined by a rheumatologist included nine patients with RA, four with osteoarthritis, two with gout, and one patient with avascu1ar necrosis .Most fluids were routinely centrifuged at 1,200 g for 10 min at 4°C to remove cells . Some fluids were subjected to a more rigorous collection procedure involving centrifugation in plastic tubes at 5,000 g in a Sorvall high-speed centrifuge for 20 min, in order to minimize the possibility of contamination with platelet products released in vitro. The cell-and platelet-free supernatants were then collected with a glass pipette that was left in the tube at 37°C . Clotted material that formed around the glass pipette was discarded . The fluids were stored at -70°C until assay.Assaysfor 7GF--ß . A radioreceptor assay for TGF ß was performed using a previously described procedure (12) . Briefly, AKR-2B fibroblasts were plated in six-well culture plates at 1-2 x 105 cells per well using McCoy's 5A medium with 5% FCS . The next day, cells were washed three times with PBS and incubated for 2 h in the presence of 0 .25 ng of '2'I TGF p in 1 .0 ml of binding medium, with or without further additions. Nonspecific binding was determined by the addition of 1 gg of 50% pure unlabeled TGFP .After a 2-h incubation at room temperature with rocking, the cells were washed, released from the plate with collagenase, and cell-bound 125 1TGF-ß was measured in a gamma counter. Results were expressed as nanograms per milliliter TGF0 calculated from a standard curve (see Fig . 1) . The concentrations of TGF ß-competing activity in synovial fluids (Table I) were derived from triplicate determinations at a final dilution that would yield a 40-60% inhibition of binding.Two cell lines were also used in soft agar assays for TGF-ß . AKR-2B cells were assayed in the presence of serum as previously described (13) . Base layers of 0 .8% agar in McCoy's
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In a number of clinical conditions the response of the level of blood sugar to a given dosage of insulin is less than that obtained in normal individuals. This phenomenon is commonly termed insulin resistance. Soon after the discovery of insulin numlerous investigators described
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