Activated peripheral blood mononuclear cells detected in lupus patients using cDNA coding for proliferating cell nuclear antigen.

Abstract The expression of proliferating cell nuclear antigen (PCNA) mRNA in peripheral blood mononuclear cells (PBMCs) from patients with systemic lupus erythematosus (SLE) was measured by dot blot hybridization using a PCNA cDNA, and correlated with the percentage of PCNA-positive cells detected immunohistochemically using a monoclonal anti-PCNA antibody. PCNA-positive PBMCs were detected in 72.2% of SLE patients (n = 36), which is significantly more than among healthy controls. In addition, among those in whom PCNA expression was detected, the percentage of PBMCs expressing PCNA was significantly higher in SLE patients (mean 2.5% vs. 0.15%). The level of PCNA mRNA was increased in PBMCs from 83.3% of SLE patients, and was significantly correlated with the percentage of PCNA-positive cells (r = 0.54, P < 0.01) and with the disease activity score (r = 0.56, P < 0.01). A longitudinal study of two SLE patients confirmed that PCNA mRNA expression and the percentages of PCNA-positive cells varied in parallel with disease activity. Thus, an analysis of activated PBMCs from SLE patients using PCNA cDNA may be a useful method by which to estimate SLE disease activity.

Liposome mediated dissipation of valinomycin-imposed potassium potential across erythrocytes membrane.

Influence of liposomes made of phosphatidylcholine (PC) on the valinomycin-imposed potassium potential across erythrocyte membrane was examined by measuring the fluorescence change of the potential-sensitive cyanine dye. We concluded that the liposomes modulate ion selectivity of the membrane embedded valinomycin, on the basis of the following lines of evidence. (i) The valinomycin-imposed potassium potential across erythrocyte membrane (interior negative) was dissipated in the presence of PC-liposomes. (ii) When PC-liposomes were added to the cell suspension before the valinomycin, a membrane potential could not be imposed. (iii) Liposomes containing only the PC of saturated fatty acids were inactive in the potential dissipation, whereas the liposomes containing PC of unsaturated fatty acids were fully active. (iv) Liposome-mediated dissipation of the imposed-membrane potential was similarly observed in the resealed erythrocyte ghosts. (v) The liposomes did not show a detectable effect on the gramicidin-mediated proton potential. (vi) The effect of liposome was somewhat analogous to the nigericin-mediated dissipation of the valinomycin-imposed potassium potential.