Naproxen is a nonsteroidal anti-inflammatory drug commonly used in the clinical treatment of joint disease. In this study, its effect in vivo on the biochemical composition, metabolic activities, and metalloproteinase activities of normal canine articular cartilage was analyzed. The articular cartilage from the knee joints of dogs who had been given naproxen for 4 weeks to maintain a serum level of 40-50 micrograms/ml was examined. Control animals were given a placebo. Treatment with naproxen was not found to change the composition (water, collagen, and proteoglycan) of the articular cartilage. The culture studies of cartilage explants indicated that proteoglycan synthesis rates were unaffected by the treatment with naproxen but that proteoglycan release from the tissue was suppressed. Analysis of the cartilage for matrix metalloproteinase activities showed reduced activity of neutral matrix metalloproteinase by 80%, of collagenase by 40%, and of gelatinase by 87%, with no change in activity of acid metalloproteinase or of tissue inhibitor for metalloproteinase. These findings indicate that in vivo treatment with naproxen has the capacity to modulate catabolic activities in articular cartilage.

This study delineated the distribution of reactivity of malignant human lymphoid cells with monoclonal antibodies Leu 1 and OKT1, and correlated this expression with that of conventional lymphoid cell markers. The presence of Leu 1 on benign lymph nodal T‐cells and its absence from benign lymph nodal B‐cells was confirmed. Twenty‐two T‐cell neoplasms, expressing a variety of intrathymic and mature peripheral phenotypes, expressed Leu 1, but this expression was heterogeneous with respect to percent‐positive cells and antigenic density, and appeared to correlate with stages of T‐cell differentiation. This study demonstrated the expression of Leu 1 by 33 of 36 cases of B‐CLL, by 10 of 15 cases of the closely allied small lymphocytic cell lymphoma, and by 9 of 29 follicular center‐cell lymphomas. This included B‐cell malignancies of each surface immunoglobulin isotype, and some cases associated with a monoclonal protein spike. Leu 1 was not expressed by myeloma plasma cells, and was absent from non‐B, non‐T acute lymphoblastic leukemia cells in each of 15 cases studied. Finally, Leu 1 and OKT1 were expressed in parallel, with respect to percent‐positive cells and staining intensity, on benign and malignant T‐cells, and on malignant B‐cells, wherever studied. Possible explanations for this shared antigen are the existence of a minor Leu 1+ B‐cell subset, a transformation‐associated event, or glycosylation.

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We report in this paper the generation and characterization of three monoclonal antibodies, designated alpha BL1, alpha BL2, and alpha BL3, that recognize distinctive antigens unrelated to complement, Fc, and mouse erythrocyte rosette receptors, which are preferentially expressed on B lymphocytes. alpha BL1 recognizes a heat stable nonimmunoprecipitable antigen, possibly glycolipid in nature. Alpha BL2 recognizes a nonreducible single polypeptide with a m.w. of 68,000 that occasionally co-precipitates with a p29,34 complex of HLA-DR antigens. Alpha BL3 recognizes a nonreducible single polypeptide with a m.w. of 105,000 with an acidic pI point. We demonstrated that BL1 is expressed on fetal liver hematopoietic cells, a small subset (5 to 15%) of Ficoll-Hypaque-separated normal bone marrow cells, and on a subpopulation of nonadherent, non-E rosette-forming cells and granulocytes. BL2 is expressed on fetal liver hematopoietic cells, on 3 to 7% of normal bone marrow cells, and on a majority (40 to 70%) of nonadherent, non-E rosette-forming cells with a distinctive pattern similar to that of HLA-DR. BL3 is expressed on a subpopulation of nonadherent, non-E rosette-forming cells, and on occasional cells in the monocyte-enriched adherent cell population. The peak fluorescence for BL2 is substantially higher than that of BL1 and BL3, indicating higher BL2 antigen density. All three antigens are absent from thymocytes and E rosette-positive T cell fractions obtained from various lymphoid tissues. Cellular distribution of the BL antigens on various well-characterized established hematopoietic cell lines, leukemias, and malignant lymphomas, in conjunction with the results of the in vitro activation and TPA-induction experiments, suggest that BL1 is expressed during early developmental stages of B cell differentiation, whereas BL3 is expressed at the later stages. BL2 expression spans immature and mature stages of B cell differentiation, with the exception of mature plasma cells. The alpha BL antibodies described here should prove to be useful in the investigation of B cell differentiation and in the clinical diagnosis of lymphoid neoplasms.