PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Complement C3”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,135 records · Page 63Linked to original sources
PubMed2004

[Immunological effects of polyacrylamide hydrogel injection in human body].

OBJECTIVE: To observe the immunologic changes in patients who have complications after polyacrylamide hydrogel (HPG) injection. METHODS: To compare the patients in the HPG injection group and the control group, the expressions of immunoglobulin IgG, IgM, IgA and complement C3, C4 of serum were measured by immunoturbidimetry. RESULTS: The expressions of IgG and C3 in the injection group were lower than the control group with extremely significant difference (P < 0.01). The expressions of IgM were higher than the control group with significant difference (P < 0.05). The expression of IgA and C4 had no significant differences between the two groups. The immunologic changes had no relation to the injection doses. CONCLUSIONS: Clinical application of HPG as a soft tissue filling material may cause foreign-body rejection reaction. The long-term immunologic effect of HPG needs further observation in more cases.

Acrylic Resins↗
PubMed1994

Molecular analysis of C3 allotypes in patients with systemic vasculitis.

The third component of complement (C3) exists in two main allotypic forms, C3S and C3F, distinguished at the DNA level by a single base change. An increased frequency of the rarer C3F allele has been reported in patients with the autoantibody nephritic factor and in several other autoimmune conditions such as rheumatoid arthritis and IgA nephropathy. Studies of the immunogenetic factors predisposing to the development of systemic vasculitis have produced conflicting results and no major genetic predisposing factors have been identified. We have studied the C3S/F polymorphism in 63 patients with systemic vasculitis using DNA allotyping by the amplification refractory mutation system, a modification of the polymerase chain reaction. The allele frequency in these patients was C3S 0.71, C3F 0.29 (expected C3S 0.8, C3F 0.19; chi-squared = 5.1, P < 0.025), with the average relative risk for the development of systemic vasculitis associated with the presence of a C3F allele being 2.6. Moreover, there was a marked excess of C3FF homozygotes (11/63, [17.5%], versus 4% expected: chi-squared = 9.5, p < 0.01). The average relative risk for the development of systemic vasculitis in C3F homozygotes was 5.1, indicating a gene dosage effect. These data indicate that the C3F allele is associated with a predisposition to the development of systemic vasculitis and that C3F homozygotes are at particularly high risk. This association is the strongest genetic factor reported so far for this group of diseases.

Alleles↗
PubMed1995

Hantaan virus infection with acute renal failure.

We report on 10 patients with acute renal involvement in Hantaan virus infection observed at the Department of Nephrology, Faculty of Medicine, Skopje, Republic of Macedonia, during a period of 3 years (October 1987-July 1990). Eight patients were male and 2 were female, aged 37.5 +/- 4.8 years. The diagnosis of Hantaan virus infection was proven by an indirect immunofluorescent and ELISA test with a significant increase of the titer after a week to ranges from 1:512 to 1:2,048. Percutaneous renal biopsy was performed in 3 cases using standard procedures for optical and immunofluorescent microscopy. Fever, weakness, headache, conjunctival injection, hematuria, and lumbar pain were clinical features all patients had in common. Complete anuria was noted in 7 out of 10 and oliguria in the other 3 of the 10 cases with serum levels of creatinine 967 +/- 152.6 mumol/L. Other following laboratory findings were leukocytosis in 10 out of 10 patients, with neutrophylia, and reduction of serum sodium and potassium in 8 out of 10, and a decrease in serum complement C3 in 3 out of 10 patients. Percutaneous renal biopsy confirmed interstitionephritis in 2 out of 3 biopsied patients and acute diffuse proliferative glomerulonephritis in the third. Interstitial mononuclear infiltration with dominant T cells proven with monoclonal antisera (direct immunoperoxidase method) was present in all 3 cases. The outcome of the disease was good in 8 of the 10 patients with a development of polyuric phase and complete recovery of renal function later. One patient with interstitial lesions on biopsy developed chronic renal failure, and the other with a concomitant brucellosis died during the polyuric phase of the disease.

Acute Kidney Injury↗
PubMed2006

Increased levels of acylation-stimulating protein in interleukin-6-deficient (IL-6(-/-)) mice.

IL-6-deficient (IL-6(-/-)) mice develop obesity at 6-7 months of age. To elucidate the mechanisms of this mature-onset obesity, global gene expression profiles of 3-month-old preobese IL-6(-/-) were compared with those of IL-6(+/+) mice using DNA arrays. Genes that were up-regulated in IL-6(-/-) mice included the factors transthyretin and properdin in white adipose tissue and adipsin in muscle. These factors have been shown to influence the formation of acylation-stimulating protein (ASP), a cleavage product of complement C3. ASP stimulates the synthesis of triacylglycerol in adipocytes, and ASP-deficient mice are resistant to diet-induced obesity. In line with the increases in transthyretin, properdin, and adipsin, ASP levels in serum were increased by 31-54% in IL-6(-/-) compared with IL-6(+/+) mice. Furthermore, IL-6 replacement treatment in IL-6(-/-) mice decreased ASP levels significantly by 25-60%. In conclusion, ASP levels are increased in preobese IL-6(-/-) mice. This increase may result in increased triacylglycerol formation and uptake in IL-6(-/-) adipocytes and thereby contribute to the development of obesity in IL-6(-/-) mice.

Adipocytes↗
PubMedDate not supplied

[Characteristics of the humoral immune system and lipid peroxidation processes in people living in territories contaminated with radionuclides].

Among 33 patients with Stage II hypertension, 25 persons were inhabitants of the Russian radionuclide-contaminated areas and 8 patients had no prior contacts with ionizing radiation (control). All the patients examined were maintained within 4 weeks on a diet, radioprotective effect of which was realized due to the elevated content of sulfur containing amino acids, antioxidants and complexes. In the patients who lived in the radionuclide-contaminated areas, a moderate activation of lipid peroxidation was detected simultaneously with marked alterations in the humoral component of the immunity system, which involved a considerable increase in the levels of IgG and complements C3 and C4. A decrease in content of malonic dialdehyde and diene conjugates as well as normalization of IgG and decrease in content of IgA, IgM and C3 were observed in blood plasma of the patients on diet. Supplementation of omega 3 polyunsaturated fatty acids (omega 3-PUFA), 5 g/day and alpha-tocopherol, 12.5 mg/day, to the diet elevated the serum concentrations of all lg classes, which suggests the presence of an immunomodulating effect of omega 3-PUFA. Moreover, the content of malonic dialdehyde was not increased in blood plasma if 3-PUFA was used. Hence, increased alpha-tocopherol levels should be used in the treatment of these patients with omega 3-PUFA (up to 5-7 mg per g PUFA) in order to stabilize lipid peroxidation.

Accidents↗
PubMed1986

Correlation of renal histology with outcome in children with lupus nephritis.

We assessed renal histological features in 20 children with diffuse proliferative lupus nephritis (DPLN) to determine whether they were useful in predicting clinical outcome. Renal biopsies were analyzed by assigning scores indicating an activity index (AI) and chronicity index (CI). Clinical assessment of renal function at biopsy and outcome were graded according to urinalysis, serum creatinine, need for dialysis and/or transplantation, and/or death from end-stage renal failure. Renal function at biopsy correlated significantly with AI and CI. Serum complement (C3 and C4) correlated significantly with CI but not with AI. The usefulness of the clinical grading system was confirmed in ten patients who underwent repeat biopsies. Of these, four converted from DPLN to mesangial or membranous lupus and showed improvement in their grade, while only one of the six with DPLN on both biopsies improved. After a mean follow-up of 4.0 years, 14 of the 20 patients showed clinical improvement, four were unchanged, and two were worse. CI predicted clinical outcome (P less than 0.01) but AI did not. Histologic scores of AI and CI obtained from renal biopsies showing DPLN may be useful in predicting therapeutic responses and designing prospective clinical trials to determine optimum management of children with DPLN.

Adolescent↗
PubMed2003

Haemolytic uraemic syndrome and mutations of the factor H gene: a registry-based study of German speaking countries.

BACKGROUND: The aetiology of atypical haemolytic uraemic syndrome (aHUS) is, in contrast to classical, Shiga-like toxin induced HUS in children, largely unknown. Deficiency of human complement factor H and familial occurrence led to identification of the factor H gene (FH1) as the susceptibility gene, but the frequency and relevance of FH1 mutations are unknown. METHODS: We established a German registry for aHUS and analysed in all patients and 100 controls the complete FH1 gene by single strand confirmational polymorphism and DNA sequencing. In addition, complement C3 and factor H serum levels were assayed. Demographic data at onset of aHUS and follow up were compared for the mutation positive and negative groups. RESULTS: Of 111 patients with aHUS (68 female, 43 male, mean age 33 years) 14% had FH1 germline mutations, including two of eight patients with familial aHUS. For each of these eight patients, both parents were tested, and we were able to trace the mutation for five cases. In the other three cases (one with the mutation 3749 C/T, one with 3200 T/C, and one with 3566+1 G/A), we could not detect the mutation in either parent, although paternity was proven by genetic fingerprinting, suggesting that these subjects have new mutations. C3 was decreased in five mutation carriers but also in two non-carriers, and factor H was decreased in none of the carriers, but elevated in six carriers and 15 non-carriers. Clinical parameters including associated medications and diseases, and outcome of aHUS and of post-aHUS kidney transplantation were similar in the mutation positive and negative groups. CONCLUSION: FH1 germline mutations occur with considerable frequency in patients with aHUS. Hypocomplementaemia is not regularly associated with a germline mutation, and factor H serum levels can even be elevated. Screening for FH1 mutations contributes to the classification of aHUS.

Adult↗
PubMed1994

Overexpression, purification, and characterization of third component of complement.

The third component of complement (C3) plays a critical role in both pathways of complement activation by interacting with numerous other complement proteins. To elucidate the molecular features of C3 that relate to the functional activities of the molecule, we expressed the cDNA of human complement component C3 in cultured insect cells using a baculovirus expression vector system derived from the baculovirus Autographa california nuclear polyhedrosis virus (AcNPV). The expression of C3 was controlled by the promoter of the polyhedrin gene and, when recombinant baculovirus infected insect cells were cultured in serum-free medium, C3 was detected at a level of 10 micrograms/ml of culture medium. Characterization of the recombinant C3 (rC3) by SDS-PAGE revealed that the C3 gene product was translated as a 188 kDa protein comprised of two chains of 115 kDa and 73 kDa analogous to the alpha and beta chains of serum-derived human C3 (sC3). An analysis of the glycosylation pattern of purified rC3 revealed that, whereas both the alpha and beta chains were glycosylated as in sC3, the proC3 moiety of rC3 also was glycosylated. When rC3 was produced in the High Five cell line of insect cells and evaluated for reactivity with a panel of anti-C3 monoclonal antibodies (MoAb), the results suggested that the conformation of the baculovirus expressed C3 was similar to that of native C3. When the rC3 was purified by anion exchange column chromatography, it was able to react with several C3-binding proteins (CR1, P and H), reconstitute C3-deficient serum and support the activation of both complement pathways thus demonstrating that a baculovirus-expressed C3 can participate in the formation of and can be cleaved by both the classical and alternative pathway convertases. Incubation of rC3 with factor I and H revealed that both C3 and proC3 are susceptible to cleavage by factor I.

Animals↗
PubMed1992

Diurnal tear cycle: evidence for a nocturnal inflammatory constitutive tear fluid.

To investigate the tear film in the closed eye, microliter tear samples were collected without overt reflex stimulation throughout the diurnal cycle, with closed eye samples recovered immediately upon eye opening. Samples were subjected to agarose, polyacrylamide, and two-dimensional electrophoresis, coupled with immunofixation, immunoblot, and lectin blot assays. Major protein constituents were densitometrically and immunologically quantified. Results revealed a distinct progression in composition from reflex to open to closed eye tear samples. Total protein increased from 6.0 to 9.0 to 18.0 mg/ml, secretory IgA increased from less than 0.23 to 0.85 to 8.40 mg/ml, and serum albumin increased from 0.02 to 0.06 to 1.10 mg/ml. In contrast, concentrations of the major reflex tear components (lysozyme, lactoferrin, and tear specific prealbumin) remained essentially static. Immunoblot assay for complement C3 and C3c revealed that eye closure was associated with C3 activation. Results indicate that: (1) the reflex and closed eye tear layers represent opposite extremes in composition and likely origins, with open eye tear film suggesting an intermediate origin; (2) reflex tears are derived from a neurologically inducible lacrimal or accessory gland secretion composed almost exclusively of lysozyme, lactoferrin, tear specific prealbumin, and a minor mixed alpha to beta globulin fraction; (3) upon eye closure, reflex secretion ceases or greatly diminishes, with ongoing slower flow maintained by a constitutive secretion composed almost exclusively of secretory IgA; (4) the closed eye environment induces a subclinical inflammation, accounting in part for the marked rise in albumin concentration. This increase, coupled with that of secretory IgA, may play a critical role in protecting the closed eye environment from pathogens. However, this may render the closed eye environment particularly vulnerable to inflammatory and immune-mediated pathological processes, such as those seen with extended wear soft contact lenses.

Adult↗
PubMed1996

Distribution of activated complement, C3b, and its degraded fragments, iC3b/C3dg, in the colonic mucosa of ulcerative colitis (UC).

The third component of complement (C3) is central to both the classical and alternative pathways in complement activation. In this study, involvement of C3 activation in the mucosal injury of UC was investigated. We examined the distribution of activated (C3b) and degraded fragments (iC3b/C3dg) of C3, terminal complement complex (TCC), and complement regulatory proteins in normal and diseased colonic mucosa including UC and other types of colitis using immunohistochemical techniques at the level of light and electron microscopy. While C3b and iC3b/C3dg staining was negligible in the normal mucosa, iC3b/C3dg and, to a lesser extent, C3b were deposited in UC mucosa along the epithelial basement membrane. The deposition was enhanced in relation to the severity of mucosal inflammation (C3b, P less than 0.05; iC3b/C3dg, P less than 0.01). Epithelial deposition of TCC was not observed in most UC mucosa. Immunoelectron microscopy showed that C3b and iC3b/C3dg were distributed mainly along the epithelial basement membrane and the underlying connective tissue in a granular, studded manner, and weakly present along the basolateral surface of epithelial cells. These C3 fragments were also deposited in inflammatory control mucosa such as ischaemic and infectious colitis. Our findings suggest that deposition of the C3 fragments occurs in inflamed colonic mucosa of diverse etiologies, including UC, but to define a role of the deposition in the development of mucosal injury in UC awaits direct study.

Adult↗
PubMed1983

Plasma exchange in autoimmune hemolytic anemia (AIHA).

Plasma exchange therapy in autoimmune hemolytic anemia (AIHA) was used in four patients (two with warm hemolytic anemia and two with cold hemolytic anemia). The size of each plasma exchange approximated 1 plasma volume; three consecutive daily exchanges removed 80-90% of the immunoglobulins--immunoglobulin G (IgG) and immunoglobulin M (IgM)-, complement (C3, C4), and reduced antibody titers. Transfusion requirements dramatically decreased after plasma exchange in each case. In two patients, red blood cell (RBC) survival studies were performed to more accurately assess the effect of plasma exchange therapy, since steroid and/or immunosuppressive therapy was given concomitantly. In one case of cold AIHA, homologous 51Cr-RBC were injected 4 days prior to plasma exchange and repeat injection (same donor) following completion of plasma exchange. The survival curve prior to plasma exchange therapy had a T 1/2 = 7.8 days (r = -0.988) and after plasma exchange therapy had a T 1/2 = 20.4 days (r = 0.925). RBC survival studies using homologous 51Cr-RBC were also performed in a patient with warm AIHA. The survival curve before plasma exchange had a T 1/2 = 2 days (r = -0.95), and postplasma exchange a T 1/2 = 1.8 days (r = -0.91). Plasma exchange therapy seems to have a beneficial effect in cold rather than warm autoimmune hemolytic anemia.

Adult↗
PubMed2006

The role of complement in the adherence of microbubbles to dysfunctional arterial endothelium and atherosclerotic plaque.

OBJECTIVE: To determine whether serum complement C3 mediates adherence of albumin-encapsulated microbubbles to vascular endothelium in the development of atherosclerotic plaques. METHODS: Adherence of microbubbles to aortic endothelium was examined with scanning electron microscopy following intravenous injection of 20% intralipid in wild-type mice, genetic complement-deficient mice (C3-/-), and in pharmacologic C3-depleted wild-type mice. In a second experimental model, atherosclerostic plaque was induced in apolipoprotein E-deficient mice (apoE-/-), and adherence of microbubbles to atherosclerotic plaques was evaluated using fluorescent microscopy of fluorescein isothiocynate-conjugated microbubbles. Finally, imaging of aortas was performed in eight rats (four JCR:LA-cp atherosclerosis-prone rats on high cholesterol diets; four controls) following intravenous albumin microbubble injections (PESDA) to determine whether microbubble adherence to the endothelium could be detected with low mechanical index pulse sequence schemes. RESULTS: Scanning electron microscopy confirmed the adherence of microbubbles to the endothelial cells of the aorta in wild-type mice following induction of hypertriglyceridemia but not in C3-depleted mice. Microbubble adherence to the endothelial surface of atherosclerotic plaque was confirmed in all apoE-/- mice (median 172 microbubbles/field; compared to a median of 3 microbubbles/field in cobra venom factor-treated apoE-/- mice; p < 0.001). Low mechanical index ultrasound imaging detected microbubble adherence in all JCR atherosclerosis prone rats even in the absence of vasomotor or phenotypical evidence of endothelial dysfunction. The numbers of adherent microbubbles correlated with serum triglyceride levels, and were seen in conjunction with increased endothelial nitric oxide synthase activity. CONCLUSIONS: Complement C3 binds to albumin-encapsulated microbubbles and mediates microbubble adherence to vascular endothelium both early and late in the atherosclerotic process.

Albumins↗
PubMed2000

The significance of stress hormones (glucocorticoids, catecholamines) for eruptions and spontaneous remission phases in psoriasis.

BACKGROUND: In an earlier paper, it was described how acute eruptions of psoriasis may be produced in phases of immune deficiency and in the presence of bacterial antigen-releasing inflammatory foci, whereas clinical spontaneous remissions are produced in phases of immunologic activity. Therefore, it was of interest to investigate whether the stress hormones cortisol/epinephrine are involved in triggering such deficiency and activity phases. METHODS: During a series of investigations lasting up to 3 years in 95 patients, the following were determined: cortisol/epinephrine levels, polyclonal serum immunoglobulins IgM, IgG, and IgA, total serum IgE, complement C3 and C4 proteins, T cells and subpopulations, as well as streptococcal titers ASO/ADNase B, severity index (PASI) RESULTS: Phases of clinical inactivity are associated with the mechanism, "immunologic regulation," where antibacterial titers are elevated, but all other parameters are unremarkable. Eruption phases (in 32 of 95 patients) showed absolute increases in serum cortisol levels and antibacterial titers, and decreases in serum epinephrine (adrenaline) levels. Phases of spontaneous remission (in 25 of 32 patients) showed, in contrast to the eruption phases, absolute increases in serum epinephrine levels, and significant falls in serum cortisol levels and bacterial titers. CONCLUSIONS: On the basis of these results, the participation of the immune system is confirmed in the pathogenesis of psoriasis, which is subject to control by higher neurohormonal systems. Cortisol may be involved in the clinical eruption phase, and epinephrine in the remission phase. Both hormones are true antagonists and have important effects on the human immune system if produced in excess via the pituitary-adrenal axis. Infection with Streptococcus pyogenes is an additional trigger for the dermatosis.

Adolescent↗
PubMedDate not supplied

[Selective binding in vitro of a modified form of the C3 component of complement to human erythrocytes].

C3 was bound to human erythrocytes from autologous plasma or from serum brought to low ionic strength (mu less than or equal to 0.03) and pH between 4.0 and 5.0, then subsequently incubated with erythrocytes (50/1, v/v) for 20 min at 0 degree C. This capacity was preserved up to 72 h by prolonged incubation at 20, 25 or 37 degrees C, whereas it was quickly lost by incubation at 0 degree C. C3 binding did not require complement activation and was not observed with neuraminidase-treated erythrocytes. Crossed immunoelectrophoretic analysis of the pretreated serum or plasma revealed that a fraction having more cathodal migration than that of native C3 was generated upon incubation in the above-mentioned conditions. This fraction appeared able to selectively bind to the erythrocytes. Cell-bound C3 reacted positively to antisera against C3a, C3c, C3d or native C3; they rosetted positively with EAC3b, clearly showing that this C3 binding was not dependent on the proteolysis of C3 and that it concerned the acceptor sites on the cells, since C3b receptors were free. The functional significance of this C3 binding was also investigated: EC3 were not able to lyse through the alternative pathway, whereas lysis clearly increased when C3 was found to AET-treated erythrocytes. This finding, together with the modulation in the capacity of EC3 or E(AET)C3 to form an alternative pathway convertase by antibodies to C3c or C3d, strongly suggests a contribution of bound C3 to such a convertase. In contrast to "C3b-like" C3, this modified C3 was able to bind to acceptor sites on erythrocytes but, like the former, it retained the capacity to form an alternative pathway convertase. In this light, it may represent an intermediate between C3 and "C3b-like" C3.

Complement Activation↗
PubMed1985

Polymorphism of C3 component of complement in the Polish population. II. Rare phenotypes in C3 system.

In a sample of the Polish population including 4741 adults, 15 phenotype variants were found in 22 of them. These variants are determined by 12 rare alleles of the mean frequency 0.0023. Family studies of several probands with C3 phenotype variants have confirmed their genetic determination. They have been observed to be heterozygotes in which beside one common gene, rare codominant alleles are situated. Studies on polymorphism of C3 component carried out on numerous populations, allowed the discovery of new phenotype variants within the C3 group system. Family studies have confirmed their hereditary character and that they are determined by the alleles codominant in relation to the commonly occurring C3S and C3F. The paper presents the results of studies on the rare C3 phenotype variants encountered in the Polish population.

Complement C3↗
PubMed1977

Effect of heparin on complement activation and lysis of paroxysmal nocturnal hemoglobinuria (PNH) red cells.

The effect of heparin upon the binding of the third component of complement (C3) to PNH red cells in vitro and their subsequent hemolysis is described. Heparin, in increasing concentrations, progressively inhibits membrane C3 fixation and hemolysis when the classic complement pathway is activated by anti-red cell antibodies. Heparin has a biphasic effect upon membrane C3 fixation and hemolysis when complement is activated in serum at decreased ionic strength (sucrose lysis) or in serum at decreased pH (Ham test). Heparin in concentrations above 2 U/ml inhibits C3 binding and hemolysis while lower concentrations of heparin enhance the consequences of complement activation by these two procedures. This enhanced complement activation may explain the increased hemolysis sometimes reported in PNH patients treated with heparin, and suggests that heparin may aggravate the consequences of pathologic alternative pathway complement activation in other diseases.

Binding Sites, Antibody↗
PubMed1989

Role of serum complement, immunoglobulins, and cell-mediated immune system in the pathogenesis of spontaneous bacterial peritonitis (SBP).

Spontaneous bacterial peritonitis (SBP) is a common complication of advanced liver disease, which has a reported prevalence of between 4 and 27%. Frequent bacteremias due to inadequate host defense mechanisms, particularly the reticuloendothelial system (RES), with seeding of an ascitic fluid that lacks a normal opsonic activity, is believed to be the principal cause of SBP. Little data exist as to the role of serum levels of complement and immunoglobulins as well as the cell-mediated immune system in the pathogenesis of SBP. The aim of this study was to determine the serum levels of the third and fourth components of complement (C3, C4), total hemolytic complement activity (CH100), and properdin factor B (PFB) and immunoglobulins G, A, and M and various T-cell parameters in individuals admitted to hospital with ascites and advanced liver disease and to determine whether one or more of these factors could be used to predict the development of SBP in patients with advanced liver disease. Fourteen consecutive patients (nine male and five female; age 47.5 +/- 3.1 years, mean +/- SEM) with end-stage liver disease and ascites, who were evaluated for possible liver transplant at the University of Pittsburgh and who developed SBP, comprised the study group. The diagnosis of SBP was determined by positive ascitic fluid culture (three patients) and/or ascitic fluid neutrophil count of greater than 250 cells/mm3 (all patients). The control group consisted of 14 patients, matched for type of liver disease, age, and sex, who did not develop SBP.(ABSTRACT TRUNCATED AT 250 WORDS)

Ascites↗