Carmen L. Rosano

Inhibition of C1q functions by RHP, a protein elevated in sera from patients with rheumatoid arthritis.

We have previously shown that serum levels of C1q, unbound to C1r X C1s, are elevated in rheumatoid arthritis. We have also shown that RHP, a newly described serum protein which affects the C1q-anti C1q precipitin reaction, is also present at elevated levels in rheumatoid arthritis. We now show that RHP inhibits the hemolytic activity of C1q, disaggregates C1, and inhibits the ability of C1q bound to latex beads or to aggregated IgG to enhance the oxidative metabolism of neutrophils.

Non-specificity of biotin activity for Leuconostoc.

Summary It has been found that L. dextranicum elai is unique in that the dl-forms of oxybiotin and desthiobiotin are equal in activity to d-biotin in allowing maximum growth in an aspartate-free fructose medium. Since no increased lag period was observed the results suggest that these biotin analogs are utilized directly and without prior conversion to the vitamin. It was also found that γ-(3,4-ureylenecyclohexyl) butyric acid was not a blocking agent for this organism, but instead possessed biotin activity.

Effect of Hyaluronidase on Electrolytes (Sodium and Potassium) of Dog Synovial Fluid

Conclusions(1) The action of hyaluroni-dase increases the concentrations of both sodium and potassium in the synovial fluid of the dog. (2) Inactivated hyaluronidase has no action on the sodium and potassium in dog synovial fluid.Conclusions (1) The action of hyaluroni-dase increases the concentrations of both sodium and potassium in the synovial fluid of the dog. (2) Inactivated hyaluronidase has no action on the sodium and potassium in dog synovial fluid.

Structural, immunological and functional comparisons of factor H, rheumatoid arthritis protein (RHP), and its apparent normal counterpart (N-RHP)

The isolation and characterization of two human serum proteins, RHP and N-RHP, are described. N-RHP appears to be the normal counterpart of RHP which is found at elevated levels in sera of patients with rheumatoid arthritis [Rosano et al. (1988b) Inflammation 12, 351 - 360]. Although both proteins crossreact with anti-Factor H and have identical N-terminal amino acid sequences, they differ from Factor H in pI, solubility at low ionic strength, and in glycosylation. RHP differs from Factor H and N-RHP in antigenicity in the rabbit, in effect on the C1q-anti-C1q precipitin reaction, and in ability to disaggregate C1, the first component of the complement system. Removal of RHP, N-RHP and Factor H from binding to C1q is a prerequesite for separation of RHP and N-RHP from Factor H by anion exchange chromatography and isoelectric focusing. The finding of uniquely demonstrable RHP activity (enhancement of C1q-anti-C1q precipitin activity) in unfractionated sera from patients with rheumatoid arthritis, but not in normal sera, suggests that RHP is not an artefact of Factor H produced during isolation.

Effect of Tetracycline on Puromycin-Induced Polysome Degradation: Influence of Magnesium and Polyamines

Puromycin-induced polysome degradation has been shown to require G factor, guanosine 5′-triphosphate, and the presence of a ribosome release factor (Hirashima and Kaji, 1972, 1973). Tetracycline, which does not inhibit formation of peptidyl-puromycin (Gottesman, 1967; Sarkar and Thach, 1968) nor the guanosine 5′-triphosphate hydrolysis mediated by elongation factor Tu (Ono et al., 1969), inhibits polysome degradation. The tetracycline inhibition requires Mg2+ at concentrations above 8 mM, which are inhibitory to protein synthesis in vitro. At concentrations of Mg2+ below 8 mM, polysome degradation is insensitive to tetracycline, but not to fusidic acid. Addition of spermidine, but not of other polyamines, enables the tetracycline inhibition to occur at concentrations of Mg2+ as low as 2 mM. The inhibition by tetracycline and by fusidic acid suggests that ribosome movement may be essential for the function of ribosome release factor, or that these antibiotics may directly affect its action.