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Results for “Complement C1 Inhibitor Protein”

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At least 217 records · Page 12Linked to original sources
PubMed1998

alpha2-macroglobulin and C1-inactivator are plasma inhibitors of human glandular kallikrein.

Human glandular kallikrein (hK2) is a possible new marker for prostate cancer that is homologous to prostate specific antigen. Purified hK2 added to serum or plasma reacted with endogenous protease inhibitors to form complexes of >350, 135, and 80 kDa, and some hK2 remained free, as judged by immunoblotting. The former two complexes could be removed by specific antibodies to alpha2-macroglobulin and to C1- inactivator, respectively, and they comigrated on SDS-PAGE with complexes formed between hK2 and purified alpha2-macroglobulin or C1-inactivator. hK2 complexes of 80 kDa could not be completely removed with any anti-serpin antibody used. Thus, these may consist of more than one type of hK2 complex. In contrast, essentially all hK2 complexes were removed from seminal plasma by antibody to protein C inhibitor, demonstrating that protein C inhibitor is the only significant inhibitor of hK2 in semen. hK2 reacted more rapidly with alpha2-macroglobulin than with any other inhibitor in plasma or serum. Divalent metal ions and heparin did not appreciably affect the rate of formation of any of the hK2 complexes in serum or plasma or with purified alpha2-macroglobulin or C1-inactivator. Measurement of one or more of the hK2 forms identified here may have diagnostic or prognostic potential for prostate cancer.

Biomarkers, Tumor↗
PubMed2004

Paradoxical alteration of acute-phase protein levels in patients with chronic hepatitis C treated with IFN-alpha2b.

Previously we observed elevation of the serum concentration of two acute-phase protein (AFP) complement components (C9 and C1-inhibitor) in patients with chronic hepatitis C who responded (R) to IFN-alpha therapy, but not in non-responders (NR). In the present study we investigated the effect of high-dose IFN-alpha therapy on serum concentrations of two positive [orosomucoid (OROSO) and C-reactive protein (CRP)] and two negative [transferrin (TF) and fetuin/alpha2HS-glycoprotein (AHSG)] AFP in an outpatient setting. We investigated blood samples of 40 patients with chronic hepatitis C at the onset and at the end of a 3-month treatment with high-dose IFN-alpha2b (5 MIU/day for 6 weeks, followed by 5 MIU t.i.w.) and of 52 healthy individuals. Serum concentrations of OROSO, TF and AHSG were measured by radial immunodiffusion; CRP levels were determined by immunotubridimetry. Compared to controls, patients with chronic hepatitis C had significantly lower OROSO and CRP, and higher AHSG levels. By the end of treatment, OROSO concentration increased in R (P = 0.0054), but not in NR patients. In contrast, TF levels decreased in R (P = 0.0040), but did not change in NR patients. Similarly, in R patients, AHSG levels tended to decrease (P = 0.0942) following IFN-alpha treatment. We conclude that the acute-phase reaction is suppressed in patients with chronic hepatitis C that may be potentially related to the responsiveness to IFN-alpha therapy.

Acute-Phase Proteins↗
PubMed1996

Inflammatory reaction and capillary leak syndrome related to cardiopulmonary bypass in neonates undergoing cardiac operations.

We studied the inflammatory reaction related to cardiopulmonary bypass in 24 neonates (median age 6 days) undergoing the arterial switch operation for simple transposition of the great arteries, with respect to the development of postoperative capillary leak syndrome. Complement proteins, leukocyte count, tumor necrosis factor-alpha, and histamine levels were determined before, during, and after cardiopulmonary bypass. Additionally, protein movement from the intravascular into the extravascular space during cardiopulmonary bypass was assessed by the measurement of plasma concentrations of proteins with molecular weights ranging from 21,200 to 718,000. Capillary leak syndrome developed in 13 of the 24 neonates. Patients with capillary leak syndrome, as compared with those without, had preoperatively higher C5a levels (C5a, 3.0 +/- 0.6 microgram/L vs 0.9 +/- 0.2 microgram/L) (mean +/- standard error of the mean) (p < 0.05) and higher leukocyte counts (leukocytes, 17.9 +/- 2.1 X 10(3) cells/ml versus 11.7 +/- 0.8 X 10(3) cells/ml) (p < 0.05), suggesting in these neonates a preoperative inflammatory state. Preoperative clinical and operative data were identical in both patient groups. Before cardiopulmonary bypass, serum protein concentrations were similar in all patients. Ten minutes after institution of cardiopulmonary bypass, protein concentrations fell to significantly lower values in patients with capillary leak syndrome than in those without: albumin (19% +/- 1.5% vs 30% +/- 6% of the prebypass value, p < 0.05), immunoglobulin G (17% +/- 1.5% vs 29% +/- 5.5%, p < 0.001), and alpha 2-macroglobulin (15% +/- 1.2% vs 25% +/- 4%, p < 0.02). During cardiopulmonary bypass, albumin concentrations remained significantly lower in patients with capillary leak syndrome than in those without, whereas hematocrit values were similar in both groups. During cardiopulmonary bypass, patients with capillary leak syndrome also had lower concentrations of complement proteins C3 and C4 but not C1 inhibitor. C3d/C3 ratio and C5a levels were similar in both patient groups. In contrast, histamine liberation during cardiopulmonary bypass was significantly more pronounced in patients with capillary leak syndrome than in those without (725.2 +/- 396.7 pg/ml vs -54.1 +/- 58.4 pg/ml, p < 0.05). Tumor necrosis factor-alpha levels after protamine administration were also significantly higher in patients with capillary leak syndrome (38.1 +/- 10.0 pg/ml vs 15.3 +/- 3.4 pg/ml, p < 0.05). Leukocyte count during and after cardiopulmonary bypass was similar in both patient groups. This study demonstrates increased protein leakage as early as 10 minutes after initiation of.

Acute-Phase Reaction↗
PubMed1990

Effects of methylamine and heparin on a rapid chromogenic assay of C1-esterase inhibitor in plasma.

We describe a rapid assay of C1-esterase inhibitor (C1-inh) activity in plasma. After adding purified C1s serine protease (EC 3.4.21.42) in excess to plasma, we determine the residual C1s activity towards a new chromogenic tripeptide, CH3CO-Lys(CbO)-Gly-Arg-pNA. Optimal conditions include the addition of methylamine (final concentration 0.12 mol/L) to reduce the potential inhibitory capacity of alpha 2-macroglobulin towards C1s and the addition of heparin (final concentration 3000 int. units/L) to enhance the reaction of C1s with C1-inh. The correlation with C1-inh antigen concentrations in plasma was excellent. The estimated interassay CV was 4.3%, whereas the intra-assay CV was 2.0% for activity concentrations within the range of normal individuals (means +/- 2 SD: 70-124%), 1.3% at lower concentrations. The method is more convenient, rapid, and precise than previous methods, and C1-inh activity in plasma can be assessed within 30 min. We found that concentrations of C1-inh in plasma were low during open-heart bypass surgery.

Antigens↗
PubMed1997

Complement activation in Henoch-Schönlein purpura.

The pathogenetic mechanism underlying Henoch-Schönlein purpura (HSP) is poorly understood. Complement activation has been thought to have a role, but despite the demonstration of complement components in skin and renal biopsy material, serological evidence of complement activation is not convincing. We have assessed complement activation in 64 children with acute HSP. We used an enzyme-linked immunosorbent assay to measure plasma levels of three multimolecular complement activation protein (CAP) complexes: C1r:C1s:C1-inhibitor, C3bP and C5b-9. We found no significant difference between the levels of CAPs in children with acute HSP and a control group of children. This study does not support a role for complement activation in the pathogenesis of HSP.

Adolescent↗
PubMed1978

Disequilibrium in control of proteolysis as a cause of pre-eclampsia.

The interrelated systems which control proteolysis may go into disequilibrium during pregnancy so that a renin-like enzyme in the plasma produces effects such as the early clinical manifestations of pre-eclampsia; the overactivity of the reninlike enzyme may in turn lead to undue activity of other physiological systems including those of the coagulation and complement systems.

Antithrombins↗
PubMed1992

Kinetic differentiation between enzyme inactivation involving complex-formation with the inactivator and that involving a conformation-change step.

It has been suggested that the complexing type of inactivation in which the inactivator binds reversibly with the enzyme before inactivation cannot be differentiated kinetically from that a slow enzyme conformation change is involved as a first step [Rakitzis (1986) J. Theor. Biol. 122, 247-249]. The kinetics of the substrate reaction during modification of enzyme activity previously described [Tsou (1988) Adv. Enzymol. Relat. Areas Mol. Biol. 61, 381-436] have now been applied to this problem and equations derived to show that the slow-conformational-change type can be differentiated from the complexing type by plotting the final concentration of product formed, [P]infinity, against the reciprocal of inactivator concentration. The reaction of hexokinase with 2-chloromercuri-4-nitrophenol has been shown to involve a conformational change of the enzyme before inactivation.

Chloromercurinitrophenols↗
PubMed1992

[Angioneurotic edema caused by angiotensin-converting enzyme inhibitors].

Inhibition of angiotensin converting enzyme (ACE) may cause angioneurotic oedema. In order to define the clinical spectrum of this important adverse effect, we analysed data on 60 patients with angioneurotic oedema notified to the Drug Commission of the German Medical Association, after taking captopril (n = 24), enalapril (n = 25) or lisinopril (n = 11). In 48 cases the oedema affected the face, tongue and pharynx, while swelling of the extremities (n = 4), the trunk (n = 2) or the genitalia (n = 1) was observed less frequently. While oedema appeared most often after 1 to 21 days, it started within an hour in one patient, and only after 6 months of therapy in five patients. After discontinuation of the ACE inhibitor, the angioneurotic oedema resolved within 72 hours; additional therapeutic measures (glucocorticoids, antihistamines, adrenaline, C1 inhibitors) did not shorten the recovery time. In view of the increasing use of ACE inhibitors, the features of this unusual adverse reaction need to be widely recognized, since angioneurotic oedema of the larynx is potentially life-threatening.

Angioedema↗
PubMed2004

Human oligodendroglial cells express low levels of C1 inhibitor and membrane cofactor protein mRNAs.

BACKGROUND: Oligodendrocytes, neurons, astrocytes, microglia, and endothelial cells are capable of synthesizing complement inhibitor proteins. Oligodendrocytes are vulnerable to complement attack, which is particularly observed in multiple sclerosis. This vulnerability may be related to a deficiency in their ability to express complement regulatory proteins. METHODS: This study compared the expression level of complement inhibitor mRNAs by human oligodendrocytes, astrocytes and microglia using semi-quantitative RT-PCR. RESULTS: Semi-quantitative RT-PCR analysis showed that C1 inhibitor (C1-inh) mRNA expression was dramatically lower in oligodendroglial cells compared with astrocytes and microglia. The mRNA expression level of membrane cofactor protein (MCP) by oligodendrocytes was also significantly lower than for other cell types. CONCLUSION: The lower mRNA expression of C1-inh and MCP by oligodendrocytes could contribute to their vulnerability in several neurodegenerative and inflammatory diseases of the central nervous system.

Journal Article↗
PubMed1999

Angioedema due to acquired C1-esterase inhibitor deficiency in a patient with Helicobacter pylori infection.

The first component of the classical pathway of the complement system, C1 is regulated by a serum protein, the C1-esterase inhibitor (C1-INH). Deficiency of this protein leads to the release of vasoactive mediators (C2 kinin and bradykinin) that increase vascular permeability and can induce edema formation in subcutaneous and submucosal tissues. The genetic variant of C1-INH deficiency is inherited as an autosomal dominant trait and causes hereditary angioneurotic edema. The acquired form of C1-INH deficiency is characterized by similar manifestations and can occur in association with lymphoproliferative diseases, malignancy, immune disorders, and infections. The authors present a case of acquired C1-INH deficiency in a patient with Helicobacter pylori infection. Complete eradication of this pathogen was followed by the resolution of symptoms and normalization of serum complement levels. It seems therefore probable that in this patient, acquired C1-INH deficiency was related to Helicobacter pylori infection. To our best knowledge, no similar observations have been published so far. Specific immune reactions are important contributing factors in H. pylori. Excessive consumption of complement by antibodies directed against H. pylori is a potential cause of C1-INH deficiency observed in our case.

Adult↗
PubMed2000

Changes in the acute phase complement component and IL-6 levels in patients with chronic hepatitis C receiving interferon alpha-2b.

In order to study the effect of interferon alpha on the levels of acute phase complement proteins in vivo, serum concentrations of C9 and C1-inhibitor (C1-INH) were measured in patients with chronic hepatitis C before and 3 months after the beginning of interferon alpha2b therapy. Serum levels of the activation product of terminal complement pathway, C5b-9, HCV RNA and IL-6 were also determined. IFN alpha treatment significantly (P<0.0001) increased the serum concentrations of both complement proteins. C5b-9 levels were found to significantly decrease during the same period of time. When the patients were divided into responders or non-responders (more or less than 50% decrease in plasma HCV RNA concentrations) C9 and C1-INH levels were elevated only in the responder patients. There was no correlation between the changes of IL-6 levels or the amounts of IFN alpha administrated on one hand, and the changes in the complement protein levels on the other. These findings suggest that the marked increase in the serum concentrations of the acute phase complement proteins is a secondary phenomenon due to the IFN alpha-caused diminution of the viral load and the resulting immune complex-induced complement activation.

Acute-Phase Proteins↗
PubMed1999

[C1-inhibitor].

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Complement C1 Inactivator Proteins↗