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Biomedical subjects

K Whaley

Publications and source records attributed to K Whaley.

At least 127 records · Page 7Linked to original sources

The clinical significance of the antinuclear antibody test as a screening procedure for DNA antibodies in SLE.

During the two-year period (1st October 1974-30th September 1976), 2979 sera were tested for DNA antibodies by the Farr test. One thousand six hundred and ninety-five of these were tested because they had high ANA titres (1/256 or greater). In this group 285 sera were found to have raised DNA binding capacities (DNA-bc), 86 of which were found in patients having diagnoses other than SLE. When the diagnoses were reviewed following the finding of a raised DNA-bc, 55 of these patients were found to be suffering from SLE. Of the 1284 sera tested for DNA antibodies without the prior ANA screening procedures, 288 were positive, 36 of which came from patients not considered to have SLE; 30 of these patients were subsequently shown to have SLE. Thus the DNA-bc test is an important tool in the diagnosis of SLE, and the ANA test appears to be a valuable screening procedure. The level of DNA-bc was not of any diagnostic value.

Antibodies, Antinuclear↗

Effects of histamine on monocyte complement production. I. Inhibition of C2 production mediated by its action on H2 receptors.

Histamine produced dose-dependent inhibition of the production of the second complement component (C2) by monocytes in tissue culture. The effect was not associated with either cell death, as ascertained by trypan blue exclusion, or loss of cells from the monolayer, as determined by measuring their DNA content. The specificity of the response was shown by the failure of histidine or histamine metabolites to inhibit C2 production. Preincubation of histamine with histaminase also abrogated the histamine effect. The kinetics of the effect were extremely rapid and irreversible, most of the reduction being achieved during a 5-min exposure to histamine. The H2 receptor antagonist cimetidine was able to prevent the histamine response, whereas chlorpheniramine, the H1 receptor antagonist, had no effect. Dimaprit and 4-methyl histamine, H2 receptor agonists, simulated the effect of histamine whereas the H1 receptor agonist 2-(2-aminoethylthiazole) was ineffective, confirming that the effect of histamine on C2 production by monocytes is mediated by the H2 receptors. Thus histamine, released from basophils or mast cells by the C3 and C5 cleavage products C3a and C5a respectively, may exert a negative feedback on further C3 and C5 cleavage by limiting the formation of the C3 (C42) and C5 (C423b) convertases.

Cells, Cultured↗

Increased biosynthesis of complement components by cultured monocytes, synovial fluid macrophages and skynovial membrane cells from patients with rheumatoid arthritis.

Monocytes, synovial fluid (SF) and synovial membrane (SM) macrophages from patients with rheumatoid arthritis (RA) were maintained in short-term tissue culture for up to 10 days, and the synthesis of C4, C2, C3, C5, factor B(B), D, properdin (P), C3b inactivator (C3bINA) and beta 1H globulin studied. Functionally active C2, B, D, P, C3bINA and beta 1H were synthesized by the cells in each type of culture. C4, C3 and C5 could be detected, but were functionally inactive. RA monocytes synthesized more C2 than monocytes from patients with degenerative joint disease (DJD) (P < 0.001). Similar studies revealed that SF macrophages synthesized more C3 than SM macrophages (P < 0.001) which in turn produced more C2 than monocytes (P < 0.001). Other experiments showed that SF macrophages synthesized more of each component than the other cell types. SM macrophages made more C2 than B than RA and DJD monocytes, but synthesized only small quantities of P, D and beta 1H. RA monocytes synthesized more of each component than DJD monocytes. The results of these studies show that (1) in RA, complement components can be synthesized locally in the inflamed joints, and (2) local factors in the joints probably stimulate complement synthesis.

Arthritis, Rheumatoid↗

Effect of histamine on monocyte complement production. II. Modulation of protein secretion, degradation and synthesis.

Using immunofluorescence and pulse-label studies with 3H-labelled amino acids, histamine was shown to inhibit the secretion of newly synthesized C2, C4, C3, factor B and beta 1H globulin by monocytes in culture. The findings suggested that protein synthesis was decreased, and that the degradation of newly synthesized intracellular protein was increased in histamine-treated monocytes. The observations that all monocytes in cultures containing histamine stained for C2, C4, and C3, factor B and beta 1H, when secretion was impaired, shows that all monocytes synthesize these proteins. These results demonstrate a negative feedback loop on C3 and C5 cleavage. The anaphylotoxins, C3a and C5a, formed as a result of C3 and C5 cleavage, release histamine from mast cells and basophils. Histamine, by inhibiting the production of C4, C2, and C3 and factor B by mononuclear phagocytes, inhibits further C3 and C5 cleavage by restricting the formation of C42, C423b and C3bBbP.

Amino Acids↗

Relative importance of C3b inactivator and beta 1H globulin in the modulation of the properdin amplification loop in systemic lupus erythematosus.

Serum concentrations of C4, C3, factor B (B), properdin (P), C3b inactivator (C3bINA) and beta 1H globulin have been measured by radial immunodiffusion in sixty-two samples from thirteen patients with systemic lupus erythematosus (SLE). Significant reductions in the mean serum concentrations of C4 (classical pathway) B and P (alternative pathway) and C3 were found. In addition, the mean level of the control protein beta 1H, but not C3bINA, was reduced. Sera from thirteen patients taking during disease exacerbation (low C3) showed significantly lower levels of both C3bINA and beta 1H than sera taken from the same thirteen patients during disease remission (high C3). Serum concentrations of C3bINA correlated with B (P less than 0.005) but not C4, C3 or P, whereas levels of beta 1H correlated with C4 (P less than 0.01), B (P less than 0.005) and properdin (P less than 0.01). Serial measurements of the serum concentrations of C3bINA and beta 1H showed that levels of these protein fell during exacerbation, and such falls were more closely associated with diseases in the serum levels of the alternative pathways proteins than C4. It is concluded from these observations that serum concentrations of the control proteins C3bINA and beta 1H, especially the latter, control the extent of turnover of the alternative pathway in SLE. Metabolic studies are required to determine the causes of the decreased serum concentrations of these control proteins.

Complement Activation↗

Modulation of the properdin amplification loop in membranoproliferative and other forms of glomerulonephritis.

The mean serum concentrations of C3b inactivator (C3bINA) and beta1H globulin were measured in eighty-six sera (thirty-five membranoproliferative, thirteen membranous, thirty-one focal and seven minimal change) taken from seventy-five patients with histologically diagnosed glomerulonephritis. In none of the four groups of sera did the mean concentrations of both these proteins differ significantly from the mean levels in a group of fifty normal sera. However, in the membranoproliferative group, the mean level of C3bINA, but not beta1H, was significantly lower in the nephritic factor positive than in the nephritic factor negative group. When the eighty-six sera were considered together, serum concentrations of C3bINA and beta1H correlated with levels of C3, factor B, properdin and C4. When the membranoproliferative group was considered separately, C3bINA levels correlated with levels of C3, factor B, properdin and C4 and beta1H correlated with C3 and factor B, but not properdin or C4 in the nephritic factor negative group, but no such correlations were observed in the nephritic factor positive group. The significance of these findings is discussed in the light of current thoughts on the mechanisms of modulation of the alternative pathway.

Beta-Globulins↗

Evaluation of the C1q solid-phase binding assay for immune complexes. A clinical and laboratory study.

The solid-phase C1q binding assay for circulating immune complexes has been evaluated. The assay provides a rapid, sensitive (detecting as little as 1 microgram of aggregated IgG) and reproducible procedure for the detection of immune complexes in biological fluids. Using artificially prepared immune complexes, the assay detects complexes at four-times antigen-excess. Gel filtration over Sepharose 6B showed that these complexes were distributed over a range of molecular weights from greater than 4 x 10(6) to 300,000 daltons. Using radiolabelled anti-BSA, antigen (BSA) could be detected in these complexes. Screening of gel-filtered SLE showed that the assay detects complexes of both high and low molecular weight, but does not detect all complexes in the SLE sera. Clinical studies showed that immune complexes are frequently found in the sera of patients with SLE and measurement of the concentrations of complexes provides a more sensitive index of disease activity than either serum C3 or C4 concentrations or DNA binding capacity. In patients with RA concentrations of immune complexes were generally higher in synovial fluid than serum, although a patient with systemic rheumatoid disease with hypocomplementaemia had an extremely high level of circulating immune complexes. The assay only infrequently detects circulating immune complexes in glomerulonephritis and in renal transplant recipients. It is concluded that the assay provides a useful clinical tool, but detects only a limited species of immune complexes. It can be used in the detection of antigens in complexes.

Antigen-Antibody Complex↗

Evidence for glomerular modulation of complement activation.

Using indirect immunofluorescence, three regulatory proteins of the complement system, C1-inhibitor (C1-INH), C3b inactivator (C3bINA) and beta 1H globulin have been detected in the glomeruli of patients with glomerulonephritis associated with complement activation. C1-INH and beta 1H were found frequently but C3bINA was rarely detected (only 14 biopsies). beta 1H globulin and C3b inactivator which modulate C3b activity were never found in the absence of C3, but C1-INH was sometimes found in the absence of C1s. The patterns for staining for C1s and C1-INH, C3 and beta 1H were almost identical suggesting that the regulatory proteins are binding to the proteins they regulate, as has been demonstrated in vitro. Thus, in tissues undergoing complement-mediated tissue damage, the extent of complement activation is controlled by the normal regulatory mechanisms.

Complement Activation↗

Precipitating antibodies to cellular antigens in Sjögren's syndrome, rheumatoid arthritis, and other organ and nonorgan-specific autoimmune diseases.

The prevalence of three precipitating antibodies, anti-SS-A anti-SS-B, and rheumatoid arthritis precipitin (RAP), reacting with an extract of the human lymphoid cell line Wil2, was studied in the sicca syndrome, Sjögren's syndrome with rheumatoid arthritis, rheumatoid arthritis, various seronegative spondyloarthritides, and organ and nonorgan-specific autoimmune disease. Anti-SS-A and snti-SS-B occurred most frequently in the sera of patients with the sicca syndrome whereas RAP occurred most frequently in seropositive rheumatoid arthritis sera. However, the data did not support previous studies where patients with sicca syndrome had a high incidence of anti-SS-A and/or -SS-B antibodies but had a low frequency of RAP, and patients with Sjögren's syndrome in association with rheumatoid arthritis had a high incidence of RAP but a low incidence of anti-SS-A and/or -SS-B. Instead the three antibodies were present in both forms of Sjögren's syndrome. This suggested a difference in the diseases in the UK compared to the USA, or that these antibodies do not have the more subtle diagnostic specificity that was originally suggested.

Aged↗

Requirements for beta1H globulin and C3b inactivator in the control of the alternative complement pathway in human serum.

Using beta1H-depleted and C3b inactivator (C3b1NA)-deficient sera we have investigated the regulatory roles of beta1H and C3bINA in the turnover of the alternative pathway. Spontaneous turnover of C3 and factor B occurred in both beta1H-depleted and C3bINA-deficient sera. In neither case was C3d generated. Prevention of activation could be achieved by the addition of the missing protein, but not by increasing the concentration of the remaining protein. Thus both beta1H and C3bINA must be present simultaneously to prevent spontaneous activation of the alternative pathway.

Beta-Globulins↗

Modulation of the alternative complement pathways by beta 1 H globulin.

C3b inactivator accelerator (A-C3bINA) was isolated from human plasma. An antiserum produced against the purified protein gave a reaction of identity with beta 1 H, a well-documented contaminant of C3 preparations. Beta 1 H appears to be composed of a single polypeptide chain containing a significant quantity of carbohydrate, and having a sedimentation coefficient of 5.6 on analytical, and 6.4 on sucrose density gradient ultracentrifugation. Its mol wt based on SDS polyacrylamide gel electrophoresis and equilibrium sedimentation is approximately 150,000, whereas it elutes from Sephadex G200 with an apparent mol wt of 300,000, suggesting that beta 1 H is an asymmetric molecule. Beta 1 H potentiates the inactivation of C3b by C3b inactivator, binds to EAC43 to limit the formation of EAC43bB and EAC43bBP, and in contrast to C3b inactivator, it increases the rate of loss of hemolytic sites from EAC43bB and EAC43bBP. For the C3b inactivator-potentiating effect, beta 1 H and C3b inactivator must necessarily be simultaneously present. The kinetics of inactivation of C3b by C3b inactivator and beta 1 H are first order, suggesting that potentiation is not a multistep process. The mechanisms of binding to C3b and inhibition of the alternative pathway convertases C3bB and C3bBP are currently unknown.

Beta-Globulins↗

An examination of the immunology of cancer patients.

We have examined 111 cancer patients and 111 control individuals for general immunocompetence (haematological values, "recall" antigen skin tests, PHA and PPD induced lymphocyte transformation, serum Ig levels and lymphocyte subpopulations), for evidence of sensitisation to tumour-associated antigens (leucocyte migration test, serum inhibition of autologous leucocyte migration, lymphocytotoxicity, membrane immunofluorescence and immune adherence) and for evidence of continuing immune reactions (alterations of complement components and anticomplementary activity). Major differences between the cancer patients and controls were demonstrated by several tests of sensitisation and these also detected differences between patients with and without metastases. The only differences detected between cancer patients and controls by the tests of general immunocompetence were in serum IgG and IgA (higher in the cancer patients) and lymphocyte subpopulations ("active" T, autorosetting lymphocytes and lymphocytes forming "super-rosettes" increased in cancer patients). In a comparison of cancer patients with and without metastases, patients with metastases were less often reactive to the Candida DHS and streptokinase-streptodornase antigens and had raised circulating Fc positive cells. Abnormalities of the individual components of complement occurred in about half the cancer patients, but were equally common in those with and without metastases. Serum anti-complementary activity was very rarely detected. The tests of specific sensitisation correlated reasonably well but correlations of tests of general immunocompetence were infrequent.

Adolescent↗

Modulation of C3b hemolytic activity by a plasma protein distinct from C3b inactivator.

A human plasma protein binds to cell-bound C3b, the major cleavage product of the third component of complement. Consequent upon this binding, C3b no longer functions in either the classical or alternative pathways. This C3b inhibitory activity is a property of a protein previously designated beta 1H on the basis of its electrophoretic mobility.

Blood Proteins↗

C3b inactivator in the rheumatic diseases. Measurement by radial immunodiffusion and by inhibition of formation of properdin pathway C3 convertase.

C3b inactivator (C3bINA) has been measured in biologic fluids by radial immunodiffusion using a monospecific antiserum prepared in rabbits, and by a hemolytic assay which measures the reduction in the capacity of EAC43 cells bearing limited C3b sites to form C3B, the alternative pathway C3 convertase. The radial immunodiffusion and hemolytic assays show a good correlation (r = 0.86 P less than 0.001). Measurement of C3bINA concentrations in the sera of patients with systemic lupus erythematosus showed that during exacerbations of disease activity C3bINA concentrations tended to be lower, usually in association with reductions in C4, C3, factor B, and properdin, and sometimes with reductions of the alternative pathway proteins, factor B, and properdin alone. Supranormal values for C3bINA were found in the sera of 14 of 20 patients with seropositive rheumatoid arthritis and 3 of 9 seronegative patients, but none of 7 patients with degenerative joint disease. Synovial fluid concentrations of C3bINA, after correction for total synovial fluid protein and serum concentration of the enzyme, were significantly reduced in patients with rheumatoid arthritis compared to patients with degenerative joint disease (P less than 0.05). In both serum and synovial fluid from patients with rheumatoid arthritis, there was a good correlation between the concentrations of C3bINA and those of C3, factor B, and properdin, but not that of C4, suggesting that levels of C3bINA may serve to modulate recruitment of the properdin amplification loop in this disease.

Animals↗