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Biomedical subjects

S Ruddy

Publications and source records attributed to S Ruddy.

At least 73 records · Page 4Linked to original sources
PubMed1979

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↗
PubMed1979

Complement receptor binding of C3b-coated cells treated with C3b inactivator, beta 1H globulin and trypsin.

Treatment of 125I-C3b bound to EAC1423b with C3b inactivator (C3bINA) and beta 1H globulin (beta 1H) cleaved the alpha-chain of C3b into 65,000- and 42,000-dalton fragments, both of which remained disulfide-bonded to the intact beta-chain (C3bi). Subsequent treatment with trypsin (0.1 microgram/ml) released 125I into the supernatant and yielded cells coated with a 33,000-dalton fragment of alpha-chain, presumably C3d. These results are in agreement with those obtained by others using fluid phase C3b. C3b-coated cells (EAC1423b) adhered to complement (C) receptors on human erythrocytes, glomeruli, and monocytes. C3bi-coated cells adhered to the receptors on glomeruli and monocytes, but not to those on human erythrocytes. C3d-coated cells adhered only to the monocyte receptors. The findings suggest that the glomerular C receptor recognizes portions of the C3 molecule different from those recognized by either the erythrocyte or monocyte receptors.

Animals↗
PubMed1978

Interaction of beta1H globulin with cell-bound C3b: quantitative analysis of binding and influence of alternative pathway components on binding.

Purified beta1H globulin (beta1H) was shown to bind to C3b coated cells by both immunofluorescent and radioactive tracer techniques. With EAC43, the amount of beta1H bound was directly proportional to the amount of C3 used to prepare the cells; EA, EAC14 and EAC14oxy2 bound very small amounts of beta1H. The C3b binding site on beta1H was labile in that not all of the purified 125I-beta1H was capable of binding to C3b, even when an excess of cell-bound C3b was present. Scatchard analysis of binding of beta1H to C3b-coated cells indicated an equilibrium constant of 10(9) L/M. Deviations from linearity were regularly found on Scatchard analyses. This was consistent with the hypothesis that the beta1H binding sites exhibit negative cooperativity in that as more sites become occupied, it becomes more difficult to fill the remaining sites. The stoichiometry of the reaction between C3b and beta1H was examined using EAC14oxy23 prepared with 131I-C3 and beta1H labeled with 125I. Between 0.5--0.8 beta1H molecules were bound per C3b molecule. Other alternative pathway components influenced the binding of 125I-beta1H to cell bound C3b. Both C3b and native C3 inhibited binding of labeled beta1H at an efficiency approximately 1/1,000 that of unlabeled beta1H. Factor B inhibited binding with 1/280 the efficiency of unlabeled beta1H. Properdin caused a dose-dependent increase in the binding of beta1H; this enhancement was abrogated if B was also present in the reaction mixture. Scatchard analysis indicated that the enhancement of beta1H binding by P resulted in an increased number of available binding sites rather than an increase in the affinity of binding.

Animals↗
PubMed1977

Production of the second component of complement by human monocytes: stimulation by antigen-activated lymphocytes or lymphokines.

Human peripheral blood mononuclear cells cultured in the presence of antigen produced hemolytically active second complement component earlier and in larger amounts than did control cultures of the same cells without antigen. The increased amount of C2 in culture supernates came primarily from the adherent cell population and was due to increased synthesis as demonstrated by inhibition with 10(-4) M cycloheximide. Purified adherent monocytes produced more C2 when exposed to lymphokine-rich supernates from antigen-stimulated lymphocytes than when exposed to control supernates from unstimulated lymphocyte cultures. The increased synthesis of C2, which appeared to be mediated by a lymphokine, was partially inhibited specifically by 0.025 M alpha-L(-) fucose, a sugar which has previously been shown in inhibit the response of macrophages to migration inhibitory factor.

Antigens↗
PubMed1977

Congenital heart block in newborns of mothers with connective tissue disease.

Of 22 children with congenital complete heart block (CCHB) available for study, 14 (63.6%) were born to 11 mothers with clinical or laboratory evidence of connective tissue disease, primarily lupus erythematosus (LE). Seven mothers had both clinical and laboratory evidence of disease while four had only positive laboratory studies including fluorescent antinuclear antibody, rheumatoid factor, and depressed complement levels. In adults with systemic LE, pathologic changes in the collagen surrounding the conduction system have led to the fibrosis and death from heart block. Antinuclear antibodies of the IgG class cross the placental barrier and newborn infants have been reported with transient skin lesions of lupus. Placental transmission of such antibodies may affect the fetal cardiac conduction system, surrounding collagen, and myocardium, leading in some cases to CCHB. This is probably one important etiologic factor in CCHB even though the mother is asymptomatic during her pregnancy.

Antibodies, Antinuclear↗
PubMed1977

Erythema chronicum migrans and Lyme arthritis. The enlarging clinical spectrum.

Thirty-two patients with the onset of erythema chronicum migrans, Lyme arthritis, or both in mid-1976 were studied prospectively. The skin lesion (24 patients) typically lasted about 3 weeks, beginning as a red macule or papule that expanded to form a large ring with central clearing. Associated symptoms ranged from none to malaise, fatigue, chills and fever, headache, stiff neck, backache, myalgias, nausea, vomiting, and sore throat. Three patients had been bitten by ticks at the site of the initial lesion 4 to 20 days before its onset. Nineteen patients suddenly developed a monoarticular or oligoarticular arthritis 4 days to 22 weeks (median, 4 weeks) after onset of the skin lesion; eight developed arthritis without a preceding skin lesion. Seven of these 27 experienced migratory joint pains. Arthritis attacks, most commonly in the knee, were typically short (median, 8 days) but sometimes persisted for months. Other manifestations included neurologic abnormalties, myocardial conduction abnormalities, serum cryoprecipitates, elevated serum IgM levels, and elevated erythrocyte sedimentation rates. The diagnostic marker is the skin lesion; without it, geographic clustering is the most important clue.

Adult↗
PubMed1976

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↗
PubMed1976

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↗
PubMed1976

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↗
PubMed1975

Activation of the complement and properdin systems in rheumatoid arthritis.

The classic (C1, C4, and C2) and properdin factors (D, C3b, and B) of complement generate C3 convertases that are capable of cleaving C3 and subsequently activating C5-C9. Both C1 and factor D are serine esterases, and both convertases undergo decay and regeneration. In seropositive rheumatoid arthritis, where intraarticular activation of the classic early components (C1, C4, and C2) by immunoglobulin complexes appears to predominate, findings of relative depressions in synovial fluid levels of factor B indicate recruitment of the amplification loop (D, C3b, and B), and relative declines in properdin levels suggest activation of the properdin pathway as well. Quantitative analysis of the complement system in disease states requires several different approaches: measurement of function and antigenic concentration to assess the functional integrity of the protein; determination of component metabolism to appreciate the relative contributions of hypercatabolism and hyper- or hyposynthesis to the plasma level; and for compartmentalized disease, measurement of the component in the appropriate biologic fluid and determination of local tissue synthesis.

Antigen-Antibody Complex↗
PubMed1975

Activation of the properdin pathway of complement in patients with gram-negative bacteremia.

To determine the pathway used for activation of complement component C3, serum levels of components C1, C4, C2, C3, C5, C6, and C9 and two properdin factors, properdin and factor B, were measured in 42 patients with gram-negative bacteremia, in 19 of whom shock subsequently developed. Mean levels of the classical components C1, C4, and C2 in bacteremic patients in whom shock subsequently developed did not differ significantly (p greater than 0.05) from those of patients with uncomplicated bacteremia. Levels of properdin, factor B and C3, C5, C6, and C9 were significantly (p less than 0.05) decreased in patients with shock in comparison with those with uncomplicated bacteremia. Taken together, these findings are consistent with activation of C3 and the terminal complement sequence, C5-C9, occurring primarily by the properdin pathway, in patients with gram-negative bacteremia eventuating in shock. Biologically active products released during activation of C3-C9 may contribute to the development of shock.

Bacteria↗
PubMed1975

Acute anaphylaxis associated with serum complement depletion.

A 45-year-old woman with rheumatoid arthritis developed anaphylaxis 6 min after receiving a subcutaneous injection of lidocaine, followed by an intra-articular injection of lidocaine mixed with methprednisolone acetate. One hour after the onset of anaphylaxis, serum complement component levels were markedly depressed and remained so far 18 hr. Circulating immune complexes and antibodies to lidocaine could not be demonstrated. Neither lidocaine nor methylprednisolone acetate activated the patient's complement system in vitro. Subsequently, total hemolytic activity (CH50) levels were variable, complement component protein concentrations of C1q, C1s, C4, C2, C3, C5, C6, C9, and Factor B were normal, but hemolytic activity of C4 and C2 was diminished. Serum C1 inhibitor concentrations were normal or slightly depressed. The patient has never had any symptoms suggestive of angiodema. It is postulated that the endogenous complement abnormality present in this patient may have contributed to the anaphylactic reaction.

Anaphylaxis↗
PubMed1975

Chemotactic activity derived from interaction of factors D and B of the properdin pathway with cobra venom factor or C3B.

Interaction of D (the activated form of D) and B, factors of the properdin pathway, with C3b (the major cleavage fragment of C3) generates a convertase, C3B, which cleaves C3 and initiates the terminal complement sequence C5-C9. A functionally analogous more stable C3 convertase, CoVFB, ir formed by substituting cobra venom factor (CoVF) for C3b. Mixtures of highly purified CoVF, B, and D were chemotactic for human neutrophil polymorphonuclear leukocytes as assessed in Boyden chambers either by microscopic enumeration of migrating cells or by counting of 51Cr-labeled cells. Control mixtures containing CoVF, B, and D, reacted in the absence of Mg++, were hemolytically inactive and devoid of chemotactic activity. Over a range of doses, the chemotactic activity of mixtures yielding CoVFB correlated with their hemolytic activity. Pretreatment of neutrophils with mixtures containing CoVFB rendered them unresponsive to subsequent chemotactic stimulation by kallikrein of C5a, indicating cross-deactivation to other chemotactic factors. Similar neutrophil deactivation occurred after exposure to a mixture of C3b, B, and D in which C3B was formed; with short incubation times and high cell concentration C3B also exhibited some chemotactic activity. The chemotactic activity of C3B and CoVFB is an example of a biologic function arising from interactions among factors of the properdin pathway per se, as distinguished from the capacity of this pathway to activate C3 and the terminal complement sequence.

Animals↗
PubMed1975

Rheumatoid synovitis: complement and immune complexes.

The pattern of complement component utilization within the joint space of patients with RA is consistent with activation by immune complexes. Immunogluorescent studies of SF leukocytes revealed intracytoplasmic inclusions of immunoglobulins and complement components, particularly in cells from SF with low complement levels and containing materials which precipitated with either C1q and/or rheumatoid factor. RA patients with low levels of SF complement tended to have an unremitting course, subcutaneous nodules, and to have been treated with gold. Their joints had more periarticular demineralization, joint space narrowing, cortical impaction by X-ray; and synoviocytic giant cells, fibrosis, lymphocytes, congestion, and fibrin exudation by pathologic examination than did joints of RA patients without low levels of SF complement. Patients with systemic hypocomplementemia had active classical RA with evidence of severe joint involvement and vasculitis. These findings suggest that rheumatoid inflammation of joints is mediated by immunologic activation of the complement system.

Antigen-Antibody Complex↗
PubMed1975

Hereditary C2 deficiency in systemic lupus erythematosus and acquired complement abnormalities in an unusual SLE-related syndrome.

Early study of kindreds with C2 deficiency indicated that absence of C2 had no detrimental effect on affected individuals. Studies of additional kindreds, however, show a high incidence of SLE and other connective tissue diseases among homozygous C2-deficient members. A group of patients with an unusual SLE-related syndrome is described. In common with certain SLE patients they have marked depression of early complement components and presence of circulating Clq precipitins. It is suggested that early complement components are involved in specific host defense mechanisms and deficiencies of these components may predispose to such diseases.

Antibodies, Antinuclear↗