Unexplained severe renal failure.
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Acute Kidney Injury↗
Biomedical subjects
B A Pussell
Publications and source records attributed to B A Pussell.
The value of complement measurements in the assessment of lupus activity.
The complement system was studied prospectively in 29 patients, predominantly renal (25), with systemic lupus erythematosus (SLE) to examine the value of complement assays in the distinction between active and inactive disease. Disease activity was evaluated primarily by clinical, biochemical and histological parameters which were obtained at the time of assessment. Fourteen patients had active disease, as assessed by clinical and laboratory criteria. C1q, C4, C4a, C2, C3, C3a, C5, total haemolytic activity (CH50) and complement inhibitors were measured in each patient. The ratios of C4a:C4 and C3a:C3 were also calculated. Values for all components except C5 were different between control subjects and active patients while only CH50 was different between inactive patients and controls. All parameters except C4a:C4 and C5 were different between active and inactive patients. There was a highly significant difference in the number of active patients with reduced levels of C2, C3 and C3a:C3 compared to inactive patients (i.e. p less than 0.001) whereas lesser or no difference was observed for other parameters. The concentration of complement inhibitors was elevated in both groups. We conclude that, among readily available complement parameters, C2 and C3 provide the best assessment of disease activity in patients with SLE.
Adult↗
The inhibitory effect of rosmarinic acid on complement involves the C5 convertase.
Rosmarinic acid (RA), a naturally occurring extract from Melissa officinalis, inhibits several complement-dependent inflammatory processes and may have potential as a therapeutic agent for the control of complement activation in disease. Rosmarinic acid has been reported to have effects on both the classical pathway C3-convertase and on the cobra venom factor-induced, alternative pathway convertase. In order to define the mechanism of inhibition, the effect of RA on classical and alternative pathway lysis, C1q binding, the classical pathway convertase, the alternative pathway convertase, membrane attack pathway lysis and the generation of fragments of C3 and C5 during activation, was tested in vitro. The results showed that RA inhibited lysis by the classical pathway more than by the alternative pathway. This effect was dose-dependent with maximum inhibition of classical pathway lysis observed at 2.6 mmoles of RA. There was little effect on C1q binding or on the classical and alternative pathway convertases. However, there was highly significant inhibition of lysis of pre-formed EA43b cells by dilutions of human or rabbit serum in the presence of RA (1 mM); this was accompanied by inhibition of C5a generation. We conclude that the inhibitory effect of RA involves the C5 convertase. Such inhibition could be advantageous to the host in disorders where the terminal attack sequence plays a role in pathogenesis.
Animals↗
Post-streptococcal glomerulonephritis: studies on the interaction between nephritis strain-associated protein (NSAP), complement and the glomerulus.
Nephritis strain-associated protein (NSAP), a streptokinase produced by strains of streptococci isolated from patients with acute glomerulonephritis, is believed to be a specific antigen which participates in the production of glomerular injury. In order to investigate the mechanisms by which NSAP induces damage we have examined its potential to activate complement in vitro and to bind to isolated human glomeruli. NSAP, both alone and in combination with specific antibody, caused depletion of complement in normal human serum as measured by total haemolytic complement activity and generation of the complement breakdown products. C3a and C4a. Furthermore, Scatchard analysis showed that NSAP bound tightly to human glomeruli (Ka of 400 +/- 240 x 10(6) M) when compared to non-nephritic streptokinase (Ka of 7.3 +/- 4.1 x 10(6) M) and fully cationized human serum albumin (Ka of 0.6 +/- 0.04 x 10(6) M). These findings are consistent with the hypothesis that the deposition of streptococcal antigens within the glomerulus may precede the fixation of complement and specific antibody.
Bacterial Proteins↗
Activation of rabbit C3: studies of the generation of cleavage products in vitro and of their metabolism in vivo.
The cleavage of purified, functionally active rabbit C3 by cobra venom factor and trypsin was analysed by reducing and non-reducing sodium dodecyl sulphate electrophoresis and autoradiography. The specific aim of the study was to compare these reactions to those that occur with human C3. Analysis showed that the pattern of breakdown was very similar to that for the human protein: while the beta-chain remained intact, there was step-wise degradation of the alpha-chain to form C3a, C3b, iC3b and C3c, all of which could be identified by gel analysis. The metabolic behaviour of three of these cleavage products, C3a, C3b and iC3b, was then examined in vivo using dual isotope techniques. Rabbits were studied simultaneously with 131I-C3 and 125I-labelled C3 breakdown products. Analysis of plasma and urine radioactivity for the subsequent 72 h showed that all three breakdown proteins had rapid rates of catabolism in vivo compared to the native molecule. Specifically, 93 and 98% of C3b and iC3b, respectively, were eliminated from the plasma compartment within 10 h of injection. C3a was completely eliminated within 10 h. By comparison, native C3 showed a half-life of 29 +/- 3 h (mean +/- SD) and a fractional catabolic rate of 4.30 +/- 0.75%/h. The data support the use of this species in studies of complement behaviour in models of human immune disease and further clarify the basis for changes in plasma C3 concentration that accompany active immune complex- and antibody-mediated activity, in vivo.
Animals↗
Studies of the acute phase response in experimental serum sickness.
The acute phase behavior of C-reactive protein (C-RP), the third component of complement (C3) and total haemolytic complement activity was studied during the course of acute serum sickness (ASS) in rabbits. The specific aim was to establish whether the induction protocol caused a significant change in the serum concentration of proteins (such as C3) which could modify the outcome of the disease. ASS was induced by an intravenous (IV) bolus of bovine serum albumin (250 mg/Kg) with or without prior subcutaneous (SC) immunization with 4 mg BSA in complete Freund's adjuvant. Thirty-six animals received a full induction regimen (i.e., both SC and IV BSA). A further six rabbits were given either IV or SC BSA alone, in order to define the basis for acute phase changes observed when both injections were given. Twelve animals received a standard acute phase stimulus with intramuscular (IM) turpentine--2 or 3 ml--as a comparison to the response observed in the experimental animals. Nine, 14 and 24 animals showed a rise in C-RP (i.e., five-fold increase), C3 and haemolytic activity (greater than 25% increase) respectively after a full induction protocol. Eight, nine and five animals showed a comparable rise with IM turpentine. Studies with IV or SC BSA alone showed that the latter was predominantly responsible for the rise in C-RP and haemolytic activity. Specifically, five and four animals respectively showed a significant rise in these two parameters. Three animals showed a rise in C-RP following IV BSA alone.(ABSTRACT TRUNCATED AT 250 WORDS)
Acute Disease↗
The metabolism of C3 and C4 in patients with immune complexes and normal complement levels.
The metabolism of the complement proteins, C3 and C4 was examined in two groups of patients with a high incidence of detectable immune complexes but normal levels of complement components. The specific aim was to ascertain whether significant ongoing complement activation occurred in these patients. Eleven patients with rheumatoid arthritis (RA), 11 with infection and 11 control subjects were studied. Each received approximately 10 microCi 125l.C4 and 2.5 microCi 131l.C3 by intravenous injection. Analysis of turnover data showed that there was significant hypercatabolism of both C3 and C4 in the two study groups compared to controls. Plasma production of C4 was normal for both groups (despite the presence of C4 null alleles in six out of 11 of the RA group), while C3 production was significantly elevated in both RA and infection (p less than 0.01 and p less than 0.001 respectively). Patients with infection showed a significant increase in extravascular/intravascular distribution of both proteins. The data show that immune complex formation is associated with accelerated turnover of complement proteins, irrespective of co-existing tissue damage or changes in the serum concentration of complement components. The findings suggest that both activation of complement and maintenance or enhancement of protein synthesis are important for the efficient processing of immune complexes in vivo.
Antigen-Antibody Complex↗
Hypercatabolism of C3 and C4 in active and inactive systemic lupus erythematosus.
The metabolism of the complement proteins C3 and C4 was studied in patients with active and inactive systemic lupus erythematosus (SLE) using highly purified, functionally active preparations. Nine patients with active and eight with inactive SLE were examined and 11 control subjects. There was a significant difference in the level of double stranded DNA antibodies, immune complexes, and serum C4 between the patients with active and inactive disease. Seven of 16 patients had detectable C4 null alleles and four had low serum concentrations of complement inhibitors. Each subject received approximately 370 kBq [125I]C4 and 93 kBq [131I]C3. Both patient groups showed significant C4 hypercatabolism compared with control subjects, but there was no difference between patients with active and inactive disease. The fractional catabolic rate (FCR) of C4 was comparable in subjects with and without detectable C4 null alleles. C4 production rate was significantly lower in patients with active SLE than in control subjects. There was significant C3 hypercatabolism for both patient groups, but C3 production was normal. An inverse correlation was observed between serum concentration and FCR. There was a highly significant correlation between C4 FCR and C3 FCR for control subjects + patients with inactive disease but not for those with active SLE combined with either controls or the inactive group. We conclude that complement hypercatabolism occurs in SLE irrespective of disease activity and that accelerated turnover does not account completely for the low C4 concentration observed in patients with active disease. This low concentration also results from impaired plasma production, which could reflect a high incidence of C4 null alleles or (inhibitory) factors associated with pathological complement activation, or both. Low C4 production could affect generation of the C3 converting enzyme C4b, 2b and thus influence proceeding complement activation.
Alleles↗
Differences in the metabolism of C4 isotypes in patients with complement activation.
The metabolism of the C4 allotypes C4A3,B1 and C4A3,BO was studied in five healthy control subjects and six patients with active immunological disease (five with systemic lupus erythematosus and one with rheumatoid arthritis). The specific aim was to identify any differences in the metabolism of C4A and C4B gene products that may be linked to their documented functional differences in vitro. The fractional catabolic rate of C4A3,B1 in patients was significantly greater than that of C4A3,BO (3.98 +/- 1.37 versus 3.31 +/- 0.85%/h; mean +/- s.d.; P less than 0.05) but there was no difference in control subjects (1.95 versus 1.99%/h). The extravascular:intravascular (EV:IV) distribution ratio of C4A3,B1 was also greater in both patients (1.19 +/- 0.36 versus 0.97 +/- 0.35; P less than 0.01) and controls (0.43 +/- 0.11 versus 0.31 +/- 0.13; P = 0.01). We conclude that C4B1 was catabolized more rapidly than C4A3 in patients with pathological complement activation but not in control subjects. This difference could reflect the relatively greater extravascular distribution (i.e. EV:IV ratio) of C4B at sites of immune complex deposition or, alternatively, different rates of catabolism of inactive C4 isotypes (iC4b).
Alleles↗
Detection of lymphocytotoxic antibodies in relatives of patients with type I diabetes.
Concentrations of lymphocytotoxic antibodies were measured in serum samples from 19 patients recently diagnosed as having type I diabetes and 43 healthy relatives (33 consanguineous and 10 non-consanguineous). The specificity of the reaction was tested at 15 degrees C and 37 degrees C against T lymphocytes and purified helper/inducer and cytotoxic/suppressor subsets. The concentrations of lymphocytotoxic antibodies in each of the three test groups were significantly higher than those in controls (type I patients, p less than 0.005; consanguineous relatives, p less than 0.001; and non-consanguineous relatives, p less than 0.002). The frequency of detection of the antibodies was also greater in each of the study groups (p less than 0.01, p less than 0.01, and p less than 0.05, respectively). Cytotoxicity affected both subsets at 15 degrees C but only cytotoxic/suppressor cells at 37 degrees C. The findings of lymphocytotoxic antibodies in healthy relatives of type I diabetics, irrespective of consanguinity, suggests that an environmental agent such as a virus is at least partially responsible for this lymphocytotoxic effect. Furthermore, the residual cytotoxic/suppressor cell killing at 37 degrees C could explain the defect of suppressor cells observed in these patients.
Adolescent↗
Treatment of vasculitis with cyclophosphamide.
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Adrenal Cortex Hormones↗
Inhibition of reticuloendothelial function by gold and its relation to postinjection reactions.
A patient with rheumatoid arthritis developed severe exacerbation of symptoms 18 hours after an injection of gold thiomalate (sodium aurothiomalate). Immune complexes were present in his serum and synovial fluid; in the synovial fluid they were associated with intense complement activation. The effect of gold salts on splenic reticuloendothelial function was determined by measuring the clearance of heat-damaged erythrocytes from the circulation. Gold thiomalate (50 mg) substantially delayed clearance in the patient but had no effect in four other patients with rheumatoid arthritis who had not had a postinjection reaction. Severely impaired clearance also occurred in three out of four healthy people given 100 mg gold but they remained asymptomatic. The postinjection reaction may be an immune-complex disease that is triggered in certain patients because gold transiently inhibits reticuloendothelial function.
Arthritis, Rheumatoid↗
Defective reticuloendothelial system function in rheumatoid arthritis.
The function of the splenic reticuloendothelial system in patients with rheumatoid arthritis (R.A.) was assessed by determining the clearance of autologous heat-damaged erythrocytes from the circulation. 11/13 patients with active R.A. had a defect in the clearance of red cells and there was a significant inverse correlation between splenic function and the level of circulating immune complexes detected by a Clq-binding assay. Splenic function was normal in 13 patients with inactive disease who had been treated with either gold or prednisone. A serial study on 1 patient with active R.A. showed a clear correlation between fluctuations in disease activity, splenic function, and the level of circulating immune complexes.
Adult↗
Metabolism of human beta 1H: studies in man and experimental animals.
Metabolic studies were performed with a purified, functionally-active preparation of human beta 1H. In seven normal human subjects, the half-life ranged from 66--87 hr with fractional catabolic rates (FCR) of 1.04--1.63%/hr. Synthesis rates were 0.22--0.57 mg/kg/hr and extravascular distribution ratios were 0.34--0.67. There was evidence of extra-vascular catabolism in each subject. In sixteen patients with immunological disease four showed hypercatabolism of beta 1H. However, three patients with C3 mephritis factor (NeF) had normal beta 1H turnover despite profound reduction in C3 concentration; it is suggested that the reaction of beta 1H with the C3b. Bb convertase exposes it to a catabolic site and that in the NeF patients the NeF stabilized convertase prevents such exposure. Studies of the acute phase response were carried out in nine patients following elective surgery, with C-reactive protein (CRP) used as the control protein: six patients showed no rise in beta 1H levels and three showed a small (20%) rise whereas all exhibited a gross rise in CRP. Pre-incubation of 125I- beta 1H with NHS, with NHS in the presence of NeF and with C3b+C3b 1NA caused no change in beta 1H turnover in animals despite demonstrable total C3 conversion with the NeF.
Animals↗
Value of immune-complex assays in diagnosis and management.
Two complement-dependent assays for circulating immune complexes, the C1q-binding assay and the conglutinin binding, were used to study patients with suspected immune-complex disease. Complexes were detected most frequently in multisystem disease such as infective endocarditis (69%) and systemic lupus erythematosus (60%), and less frequently in isolated nephritis (26% of membrano-proliferative nephritis). Sequential estimations in 32 patients showed that concentrations of circulating immune complexes correlated with disease activity and were useful in monitoring therapy.
Adolescent↗
The Nail Patella syndrome--a report of a family.
This report describes two cases of the Nail Patella Syndrome with renal involvement. Pathological studies include immunochemistry, light microscopy, immunofluorescence and electron microscopy. The possibility of secondary immune damage to altered glomerular basement membrane is suggested as a cause of the progressive renal disease which occurs in some of these cases.
Adolescent↗
The complement system in infectious mononucleosis.
The complement system was investigated in 34 patients with infectious mononucleosis. Three had specific complications: one haemolytic anaemia, one severe arthralgia/myalgia and one proliferative glomerulonephritis. Complement changes consistent with classical pathway consumption were seen in ten of the uncomplicated group and the patients with haemolytic anaemia and arthralgia/myalgia. The patient with glomerulonephritis showed evidence of alternative pathway utilisation including C3 splitting activity and the deposition of properdin on renal biopsy. The complement findings suggest that circulating immune complexes are common in such patients and are likely to play a role in the pathogenesis of the complications. It is proposed that both complement pathways may be required for the effective clearance of viral material from the circulation.
Complement C1 Inactivator Proteins↗
The skin and immunosuppression.
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Adolescent↗