Synergistic action of calcium ionophore A23187 and phorbol ester TPA on B-chronic lymphocytic leukemia cells

The peripheral blood mononuclear cells from 16 patients with B-chronic lymphocytic leukemia (B-CLL, n = 13), B-prolymphocytic leukemia (B-PLL, n = 2) or hairy cell leukemia (n = 1) were incubated in the presence of the phorbol ester 12-0-tetradecanoylphorbol-13-acetate (TPA) and the calcium ionophore A23187. A synergy between these inducers was found with respect to morphological changes and B cell proliferation and differentiation. A23187 used alone did not activate the cells. B-CLL cells treated with the double stimulus acquired a plasmacytoid morphology, showed significantly higher incorporation of 3H-thymidine and 3H-uridine, and produced significantly higher amounts of monoclonal immunoglobulin compared with the same cells exposed to either of the inducers alone. These results indicate that phorbol ester and calcium ionophore act synergistically on B-CLL cells to induce proliferation and differentiation. B-PLL cells responded more vigorously to the signals provided by TPA and A23187. Previous studies showed that TPA and A23187 can mimic the two physiological second messengers diacylglycerol and inositol trisphosphate in the transduction of signals leading to cell activation, proliferation, and differentiation in normal B cells. The present findings suggest that the capacity of B- CLL and B-PLL cells to differentiate in response to signals of the second messenger pathway is intact.     

Deficiency of lubricating surfactant lining the articular surfaces of replaced hips and knees

While preceding papers have demonstrated that the active load-bearing agent in the boundary mode of joint lubrication is surface-active phospholipid (SAPL)--probably adsorbed as the outermost layer of articular cartilage--this study is designed to determine whether that layer is deficient in osteoarthritis (OA). This layer has been studied on 12 hips and 31 knees obtained from surgically replaced joints afflicted with OA. Measurement of the contact angle (theta) subtended by a droplet of saline clearly demonstrated a highly significant decrease in hydrophobicity, theta falling from 100 degrees for 13 bovine controls (78 degrees for five human controls) to 56 degrees for arthritic hips and 63 degrees and 68 degrees for the 'worn' and 'unworn' areas of arthritic knees, respectively. These changes were reflected in the quantities of SAPL (and proteolipid) recovered from the same articular surfaces by solvent rinsing, yields of SAPL being 36% lower in hips and 25% lower in 'worn' areas of knees, but not significantly different in 'unworn' areas. These results indicate that the outermost lubricating layer of SAPL deposited onto articular cartilage from SF is deficient in OA.      

p22-phox-deficient chronic granulomatous disease: reconstitution by retrovirus-mediated expression and identification of a biosynthetic intermediate of gp91-phox

Chronic granulomatous disease (CGD) results from defects in the phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, central to which is the membrane-bound cytochrome b-245. The cytochrome is composed of two protein subunits, the larger (gp91-phox) being deficient in X-linked CGD. In this study, we have analyzed expression of the cytochrome subunits in B-cell lines from two autosomal CGD patients for whom the disease is caused by deficiency of p22-phox, the smaller subunit. We report the presence of a 65-kD precursor of gp91- phox in the membrane fraction of both p22-phox-deficient cell lines, corresponding to the core protein with N-linked carbohydrate side chains in the high mannose form. Expression of p22-phox in these cells resulted in functional correction of NADPH oxidase. In addition, gp91- phox in the reconstituted cells was processed to its terminally glycosylated form. These data suggest that the association of the 65-kD gp91-phox precursor with p22-phox is a prerequisite for processing of the carbohydrate side chains to the complex form in the Golgi. The detection of this precursor will enable characterization of mutations disrupting the subunit interaction (either naturally occurring or derived by in vitro mutagenesis) and so aid in structure-function analysis of cytochrome b-245. Reconstitution of p22-phox-deficient cells shows the potential of gene therapy for this autosomal form of CGD.     

OC10Topical pimecrolimus for the treatment of erosive oral lichen planus

Introduction A wide variety of topical and systemic therapies are proposed for the treatment of symptomatic erosive or ulcerative oral lichen planus (OLP). The calcineurin inhibitor tacrolimus has been shown to be an effective means of treating OLP recalcitrant to other therapies. More recently, pimecrolimus has also been suggested to be of benefit in the treatment of such disease. Case Summary A 50‐year‐old male with a 7‐year history of histopathologically proven erosive OLP had been treated with a wide variety of topical and systemic therapies, including tacrolimus ointment. Despite this his condition remained problematic with frequent episodes of severe erosive disease predominantly affecting the buccal mucosa bilaterally. Clinical examination revealed extensive intra‐oral erosive disease, particularly affecting the right buccal mucosa. Twice daily topical application of 1% pimecrolimus ointment (Elidel®) was instituted. This resulted in resolution of his symptoms and a significant improvement in the clinical appearance of his oral lesions within a 2‐month period. Conclusion Topical pimecrolimus may be an effective therapy for symptomatic erosive or ulcerative OLP recalcitrant to other topical and systemic therapies, including topical tacrolimus. There is a need for appropriate studies to establish the efficacy of pimecrolimus for the treatment of OLP and to ascertain whether topical calcineurin inhibitors increase the malignant potential of OLP.