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Biomedical subjects

S Ikoma

Publications and source records attributed to S Ikoma.

32 records · Page 2Linked to original sources
PubMedDate not supplied

Amidase and peptidase activities of polyclonal immunoglobulin G present in the sera of patients with rheumatoid arthritis.

Polyclonal Immunoglobulin (Ig) G from patients with rheumatoid arthritis (RA) and healthy subjects hydrolyzed carbobenzoxy-Val-Gly-Arg p-nitroanilide and D-Pro-Phe-Arg p-nitroanilide. RA IgG exhibited higher activity against the former substrate, but not the latter. On the other hand, RA IgG showed reduced activity against D-Pro-Phe-Arg methylcoumarinamide, when compared with those of the healthy controls. These results suggest that RA IgGs differ from normal IgGs in the substrate specificity of amidase activity. Preliminary studies have shown that two out of three RA IgG samples cleaved a pentapeptide--Gln-Arg-Arg-Ala-Ala--which is assumed to be associated with the risk of developing RA (Gregersen, P. K. et al. (1987), Arthritis Rheum. 30, 1205-1213). By contrast, virtually no cleavage of the same peptide was observed with IgG from healthy controls. A peptide analog, Gln-Arg-Arg-Trp-Ala, was not cleaved at all by any IgGs examined either from RA patients or healthy controls.

Amidohydrolases↗
PubMedDate not supplied

Prolactin modulates the disease activity of systemic lupus erythematosus accompanied by prolactinoma.

We present a 31-year-old female patient with systemic lupus erythematosus (SLE) which was accompanied by prolactinoma. Her SLE flared when the plasma levels of prolactin (PRL) increased, and subsided when these levels decreased following the administration of bromocriptine, irrespective of the glucocorticoid dosage. For the 29 plasma samples obtained during the clinical course, PRL levels were significantly correlated to the serum anti-DNA antibody titers (r = 0.55, p < 0.05) and inversely to the serum complement activity (r = -0.33, p < 0.05). This result suggests that PRL may play a role in the pathogenesis of SLE in some patients.

Adult↗