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Biomedical subjects

B E Bourke

Publications and source records attributed to B E Bourke.

24 records · Page 2Linked to original sources
PubMed1982

Measurement of the complement C3 breakdown product C3d by rocket immunoelectrophoresis.

A method is described for quantitative measurement of C3d in plasma and synovial fluid by the use of rocket immunoelectrophoresis after fractionation of the samples with 22% polyethylene glycol. This method has the advantage over radial immunodiffusion of being more sensitive (detecting C3d down to 3 mg/l) whilst proving equally reproducible. Investigations indicate that the collection of blood samples in EDTA prevents in vitro activation of C3 even after storage for up to 6 h at room temperature and up to 12 weeks at -70 degrees C. Elevated levels of C3d were found in a proportion of SLE and RA plasma samples and in synovial fluids from patients with inflammatory synovitis. It is suggested that C3 conversion in vivo may be assessed by measurement of C3d by the technique described, and when used in conjunction with measurements of complement components and immune complexes, offers a means of investigating complement catabolism by the classical and alternative pathways.

Animals↗
PubMed1982

Circulating levels of biologically active parathyroid hormone in rheumatic diseases.

There has been doubt as to whether elevated levels of parathyroid hormone, reported previously by radioimmunoassay, reflect increased concentrations of the biologically active hormone. The application of a recently developed, highly sensitive bioassay has shown considerable disparity between bioactivity and immunoreactivity in 5 rheumatic conditions and in normal subjects. Six patients with chondrocalcinosis had elevated levels; 3 of these did not have hypercalcaemia or any obvious cause other than possible subclinical hyperparathyroidism. One patient, assayed during an acute episode, had an elevated concentration of the hormone which reverted to normal when she was asymptomatic. Most patients with osteoarthrosis (13 our of 15) had low normal levels; 2 showed unexplained slightly elevated concentrations. Of 6 patients with haemochromatosis 3 had elevated levels, though this may have been related to the associated presence of diabetes mellitus. A third of patients with ankylosing spondylitis (10 out of 30) showed elevated parathyroid hormone levels but without hypercalcaemia. A number of spondylitic patients also showed anomalous results in this assay, possibly due to the presence of an antagonist. This would be consistent with the absence of clinical or biochemical evidence of hyperparathyroidism.

Adult↗
PubMed1982

The complement fixing ability of putative circulating immune complexes in rheumatoid arthritis and its relationship to extra-articular disease.

The hypothesis that the pathogenicity of putative circulating immune complexes (CIC) in rheumatoid arthritis (RA) is related to their ability to fix complement was investigated. Three assays for CIC were employed; (a) the 125I C1q binding assay (C1q BA), (b) the C1q solid phase assay (C1q SP) and (c) the Raji cell assay (RCA). Evidence for hypercatabolism of complement was obtained by using a highly sensitive quantitative assay for C3d (a breakdown product of C3) by rocket immunoelectrophoresis. One hundred and fifty-two patients with classical or definite RA were studied; 54 had clinical evidence of extra-articular disease including vasculitis, nodules, scleritis, neuropathy and lung disease; 98 patients had clinical evidence of joint disease alone. Plasma levels of C3d were significantly elevated in the RA group as a whole 16.7 +/- 4.4 mg/l (mean +/- 1 s.d.) compared with 13.1 +/- 3.25 mg/l in a group of 55 normal controls (P less than 0.01). Elevated levels of C3d were found in 26% of all patients but occurred significantly more often in the extra-articular disease group (P less than 0.05). Fifty-four percent of patients had at least one positive assay for CIC although no individual assay was positive in more than 36% of the group as a whole. The prevalence of positive CIC was significantly greater in those patients with extra-articular disease than in those with joint disease alone (P less than 0.005). Of the total of 82 patients with putative CIC, 30 (37%) had a raised C3d level. The coincident finding of positive tests for CIC and an elevated C3d level was very significantly correlated with the presence of extra-articular disease (chi 2 = 12.7 P = 10(-3)). Whilst putative CIC are frequent in RA (54%) these findings in contrast to previous work, suggest that the majority are not associated with abnormal complement activation and may account for the relative infrequency of clinically detectable active extra-articular disease.

Adolescent↗
PubMed1981

Proteinuria in rheumatoid arthritis--drug-induced or amyloid?

Over a 5-year period 325 patients with rheumatoid arthritis received treatment with gold (162) or D-penicillamine (163). Thirty-eight (11.7%) developed proteinuria, which persisted in 10 patients; renal biopsies in these 10 patients revealed 6 cases of amyloid disease. These 6 cases illustrate the importance of investigation of rheumatoid patients developing proteinuria even when they are receiving potentially nephrotoxic drugs.

Adult↗