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Biomedical subjects

F C de Beer

Publications and source records attributed to F C de Beer.

81 records · Page 5Linked to original sources
PubMed1982

Measurement of serum C-reactive protein concentration in myocardial ischaemia and infarction.

Serum C-reactive protein (CRP) and creatine kinase (CK) MB levels were measured prospectively in patients with definite myocardial infarction, patients with spontaneous or exercise-induced angina, subjects undergoing coronary arteriography, and patients with non-cardiac chest pain. All individuals with infarction developed raised CRP levels and there was a significant correlation between the peak CRP and CK MB values. The CRP, however, peaked around 50 hours after the onset of pain at a time when the CK MB, which peaked after about 15 hours, had already returned to normal. In 20 patients who recovered uneventfully, CRP levels fell, returning to normal about seven days after infarction in four cases who were followed to this point. In eight complicated cases, including four who died within the first 10 days, the CRP level remained high. Angina alone or coronary arteriography did not cause a rise in the CRP or CK MB concentrations. Increased CRP production is a non-specific response to tissue injury and raised CRP levels in cases of chest pain with a normal CK MB indicated a pathological process other than myocardial infarction. Regular monitoring of CRP levels may also assist in early recognition of intercurrent complications occurring after myocardial infarction.

Angina Pectoris↗
PubMed1982

Correlation in rheumatoid arthritis of concentrations of plasma C3d, serum rheumatoid factor, immune complexes and C-reactive protein with each other and with clinical features of disease activity.

The concentrations of C3d in the plasma and of C-reactive protein (CRP), immune complexes and rheumatoid factor in the serum were measured in 99 patients with rheumatoid arthritis. Most patients had raised levels, the values of which correlated with disease activity assessed according to a newly described index based on multivariate analysis of subjective, semi-objective and objective features of the disease. There were also significant correlations between the values for plasma C3d and circulating immune complexes, immune complexes and rheumatoid factor, serum CRP and immune complexes, and serum CRP and plasma C3d. Measurement of plasma C3d provides a useful means of detecting in vivo complement activation, which may be involved in the pathogenesis of rheumatoid arthritis, but neither C3d levels nor any of the other variables correlated as closely with disease activity as did the serum CRP concentration.

Adult↗
PubMed1982

Isolation and characterization of C-reactive protein and serum amyloid P component in the rat.

C-reactive protein (RP) and serum amyloid P component (SAP) have been identified for the first time in rat serum and isolated by calcium-dependent affinity chromatography. Rat CRP closely resembled human CRP in its amino acid composition, in having five subunits per molecule and in its electron microscopic appearance as a pentameric annular disc. It differed, however, from all other mammalian CRP's characterised hitherto in being a glycoprotein bearing a single complex oligosaccharide on each polypeptide subunit. Furthermore one pair of tis subunits per molecule was linked by a interchain disulphide bridges whereas in other animals the subunits of both CRP and SAP are all non-covalently associated. The serum concentration of CRP in normal healthy laboratory rats and in specific pathogen-free rats was 300-600 micrograms/ml which is much greater than has been described in any other species and exceeds even maximal acute phase levels of CRP in man. Following injections of casein or croton oil, serum CRP levels rose to a maximum of about 900 micrograms/ml. Rat CRP bound to pneumococcal C-polysaccharide (CPS( but, in marked contrast to the behaviour of CRP from man, rabbit and marine teleost fish, it did not precipitate with CPS solutions, agglutinate CPS-coated sheep erythrocytes or initiate complement activation. Rat SAP, like SAP of other species, was a glycoprotein but unlike them it was composed only of a single pentameric disc not two such discs interacting face-to-face. The normal level of SAP in rat serum was 20-50 micrograms/ml, very similar to the levels seen in man, and it did not behave as an acute phase reactant in response to casein or croton-oil injections. In this respect it resembled human SAP but differed from murine SAP which is a major acute phase reactant.

Amino Acids↗
PubMed1981

Solid phase radioimmunoassays for human C-reactive protein.

Two new, rapid and sensitive radioimmunoassays for human C-reactive protein (CRP) have been established using antiserum coupled to magnetizable cellulose particles, which facilitate phase separation. A single antibody method, using solid phase anti-CRP, provides a sensitivity of 50 microgram/l with a 1-h incubation time and intra- and inter-assay coefficients of variation of 10%. A double antibody method, using fluid phase rabbit anti-CRP serum and solid phase sheep anti-rabbit IgG serum, provides a sensitivity of 3 microgram/l with an overnight incubation and intra- and inter-assay coefficients of variation of 10%. Among 468 sera from normal adult volunteer blood donors the median CRP concentration was 800 microgram/l, interquartile range 340-1700 microgram/l and range 70-29,000 microgram/l. Ninety percent of samples contained less than 3 mg/l and 99% less than 10 mg/l. Low levels (14-650 microgram/l) of CRP were detected both in amniotic fluids and in cerebrospinal fluids.

Adolescent↗
PubMed1981

Fibronectin and C4-binding protein are selectively bound by aggregated amyloid P component.

Serum amyloid P component (SAP) is a normal plasma protein, closely related to C-reactive protein, which is deposited together with amyloid fibrils in all forms of amyloidosis. It is also a normal constituent of human tissues, where it is found in vascular basement membranes and in association with the peripheral microfibrillar mantle of elastic fibres throughout the body. Very similar, highly conserved, homologous proteins are present in the sera of all vertebrates in which they have been sought, and in all cases these proteins display calcium-dependent binding affinity for agarose. The physiological function or pathogenetic significance of this reactivity are not known but we report here for the first time that under appropriate conditions human SAP can also bind certain serum glycoproteins. SAP, which had been aggregated either by direct conjugation to CNBr-activated Sepharose beads, or by complexing with anti-SAP antibodies immobilized on such beads, selectively took up fibronectin and C4-binding protein from whole normal human serum. The reaction was calcium dependent and the two ligands were bound independently of each other or of other serum constituents. Experiments with isolated fibronectin and SAP complexed by anti-SAP-Sepharose indicated that close association of pairs of SAP molecules was required for fibronectin to be bound and that each SAP dimer was capable of taking up a single molecule of fibronectin. There was no evidence that SAP in its native state in the serum was complexed with either fibronectin or C4-binding protein. The present findings significantly extend knowledge of the properties of SAP and open the way to characterisation of its physiological ligand(s) and thence to elucidation of its function.

Amyloid↗
PubMed1979

Binding of serum amyloid P-component (SAP) by amyloid fibrils.

Serum amyloid P-component (protein SAP) was found to bind in vitro to isolated amyloid fibrils of both primary and secondary types. The binding was strictly calcium-dependent, optimal uptake requiring at least 0.5 mM calcium ion. Using normal human serum as the source of protein SAP different fibril preparations became saturated with between 5--20 micrograms of SAP per mg dry weight of fibril. Isolated pure protein SAP bound in greater amounts. In control experiments SAP did not bind significantly to collagen fibrils, sheep erythrocytes, plastic shavings, or the following immobilized proteins: human kappa or lambda Bence-Jones proteins; human; rabbit or mouse IgG; human serum albumin. C-reactive protein, which resembles protein SAP structurally but has calcium-dependent specificity for different ligands, bound significantly to only one of five different amyloid fibril preparations.

Amyloid↗
PubMedDate not supplied

Correlation of clinical parameters of disease activity in rheumatoid arthritis with serum concentration of C-reactive protein and erythrocyte sedimentation rate.

Serum C-reactive protein (CRP) levels were measured in 99 patients with definite or classical rheumatoid arthritis (RA). At the same time as the serum was obtained, the activity of the RA was assessed by assigning scores to a comprehensive set of subjective, semi-objective and objective clinical features. The results confirmed that the serum CRP concentration closely reflects activity of RA and is of value in its objective assessment. Erythrocyte sedimentation rate (ESR) followed the same pattern as CRP levels but all of the subjective and semi-objective criteria correlated more significantly with CRP levels than with ESR.

Adult↗