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At least 703 records · Page 39Linked to original sources
PubMed1981

Activation of first component of complement (C1) in guinea pig serum by a polysaccharide is prevented by C1 inhibitor.

A polysaccharide (PS) purified from venom of the ant Pseudomyrmex sp. causes the activation of the classical complement (C) pathway in normal serum, but not in guinea pig serum. To investigate why C was not activated in guinea pig serum, we partially purified guinea pig C1 in the presence of the protease inhibitor p-nitrophenyl, p'-guanidinobenzoate (NPGB). This C1 preparation was activated (mu = 0.15, pH 7.5) by the PS in a dose-dependent reaction after NPGB was eliminated by dilution. The PS decreased the action of the C1 inhibitor for C1 in diluted guinea pig serum, and it also inhibited the activity of highly purified guinea pig C1 inhibitor for C1. There was a direct correlation between the concentration of the guinea pig C1 inhibitor and the loss of ability of the PS to activate C1 in mixtures of constant concentrations of purified guinea pig C1 and purified venom PS, and increasing concentrations of purified guinea pig C1 inhibitor. The activity of the human C1 inhibitor, either in diluted serum or highly purified, was not decreased by the PS. These results show that the PS does not activate guinea pig C1 in serum because its action is blocked by the C1 inhibitor.

Animals↗
PubMed1978

[Treatment of hereditary angioneurotic edema with androgens].

Hereditary angioedema (HANE) is a rare, life-threatening disease due to the deficiency of C1 inhibitor (C1 Inh). Androgen therapy has been recently shown to be effective for prophylaxis of Hane attacks. Since life-long androgen therapy may be hazardous, this study was designed to define the minimal doses required for effectiveness. Ten patients from six different families were treated during cumulative 73 months by danazol and/for methandrostenolone. One tablet/day of either drug was the minimal requirement to prevent any attack in all patients. When 3 tablets/day were given, complement abnormalities were simultaneously rapidly reversed. When 1 tablet/day was given the biological effect was barely detectable, except for C2. Serum C2 levels may, therefore, represent the best criteria of androgen therapy effectiveness. Thus, an excellent clinical result can be obtained with much lower doses of androgens than previously stated. This result seemed important with respect to the serious dose-dependent risk of androgens.

Adult↗
PubMed1981

First component of complement and thrombosis.

The previous demonstration of an association between the collagen-like region of C1q (subcomponent of the first component of complement) and human platelets and of the inhibitory properties of C1q on platelet adhesion and aggregation to or by collagen has led us to consider the first component of complement as a possible modulator of the platelet-collagen interaction. Since collagen represents a major component of the vessel wall, the modification of C1 could play a role in the development of thrombosis. We have therefore studied two patients with abnormalities of complement (low or undetectable C1, C4, C2 and deficiency in C1 inhibitor) who presented with acquired angioneurotic oedema. Both patients had a history of multiple episodes of arterial and/or venous thrombosis. Platelet associated C1q was decreased or undetectable, and this condition was associated with a specific increase of collagen induced aggregation thereby suggesting a possible mechanism for the recurrent thromboembolic episodes.

Adult↗
PubMed1980

[Hereditary angio-oedema: complement levels under treatment with danazol (author's transl)].

A mother and her son are described who both suffer from hereditary angiooedema. Both were treated with Danazol, a synthetic derivative of ethisterone. The prophylactic clinical effect seemed obvious, and also the serum concentration of the complement component C4, which had regularly been lower before treatment, became normal. However, no change of the serum concentration of the C1 esterase inhibitor could be demonstrated; this is in contrast to observations of other authors.

Adult↗
PubMed1995

Changes in the contact system during orthotopic liver transplantation with and without aprotinin.

The main cause of nonsurgical bleeding during orthotopic liver transplantation has been attributed to be hyperfibrinolysis due to high plasma levels of tissue plasminogen activator. The aim of this study was to investigate contact activation and its possible contribution to fibrinolysis during OLT with and without aprotinin. Aprotinin or placebo was given to 20 patients undergoing OLT as part of a randomized double-blind trial. Plasma samples were collected before, during, and after OLT. There were decreased preoperative levels of prekallikrein and factor XIIa (P < 0.05), with a trend for kallikrein and factor XIIa activity to increase during OLT peaking on reperfusion (P < 0.05). Kallikrein inhibition, C1 esterase inhibitor, and alpha-2-macroglobulin levels were normal before surgery, with low normal levels of antithrombin III and alpha-2-antiplasmin; these levels decreased during OLT with no specific change on reperfusion. In the aprotinin-treated group, kallikrein inhibition levels increased (P < 0.05) from preoperative mean (+/- SD) values of 101 +/- 47% to 154 +/- 42% and antiplasmin levels increased (P < 0.05) from 72 +/- 28% to 243 +/- 53% during the anhepatic phase, reflecting the effect of aprotinin. The antifibrinolytic effect of aprotinin was demonstrated by decreased levels of D-dimer on reperfusion (P < 0.05) and at the end of OLT (P < 0.001) in the aprotinin-treated group. We have shown that contact activation during OLT is minimal and that aprotinin does not alter the pattern of contact activation, but provides an antikallikrein effect.

Adult↗
PubMed1978

The second component of complement (C2) as an index of hereditary angioneurotic edema.

Measurements of C2 hemolytic activity were performed in the sera of 13 patients with Hereditary Angioneurotic Edema. Prior to treatment, C2 values correlated with the severity of the disease in each patient. During androgen therapy with Danazol, C2 measurements reflected the clinical benefit of the drug more accurately than C4 levels, thus explaining the effectiveness of low drug doses. This study also suggests that breakdown products of C2 may play an essential role in the pathogenesis of the edema.

Angioedema↗
PubMed1995

[The effect of the complement system on the acute reversible rejection of kidney transplants].

Although the involvement of complement in hyperacute renal allograft rejection is well established, its possible implication in acute reversible and chronic graft rejection remains uncertain. In recent clinical studies with a total of 83 patients undergoing renal transplantation, plasma levels of complement activation products were elevated 4-7 days before clinical diagnosis of graft rejection. Immunohistochemical analysis of biopsies revealed local complement activation with glomerular deposition of the terminal C5b-9 complex within 1 h after organ reperfusion. Increasing levels of complement activation products, preceding the clinical manifestation of renal graft rejections may be of diagnostic value in recognizing patients at risk.

Acute Disease↗
PubMedDate not supplied

Type II hereditary angioedema: presentation and follow-up of three cases.

Three cases with a family history of type II hereditary angioedema (HAE) are presented, together with their progress following treatment with stanozolol. The development of patients with this drug was satisfactory in clinical terms, as it gave rise to virtually no side effects or angioedema episodes. Only patient 3 showed an elevation of hepatic enzyme (SGOT, SGPT) levels in serum, 2 months after starting treatment. C4 values of patient 2 attained sporadic normalization in the first five months of treatment, while the values corresponding to the other two patients remained below normal at all times. The activity of C1 inhibitor (C1-INH) remained below normal in all three cases. In patient 3, it was observed that circulating immunocomplex (CIC) monitoring was, together with clinical progress, a useful method for controlling HAE activity.

Adolescent↗
PubMed1993

Complement levels of C4, C3C, factor B, and C1 inactivator in peripheral and retroplacental blood of parturient women with EPH gestosis.

The complement levels were determined in 54 parturient women with EPH gestosis, in 32 normal parturient women and in 24 normal non pregnant women. Complement components: C4, C3c, factor B /Bf/ and C1 inactivator /C1 INA/ were measured by radial immunodiffusion. Peripheral and retroplacental blood were examined. Concentrations of C4, C3c, Bf in peripheral blood of both groups of parturient women were significantly higher than in normal non pregnant women. Peripheral blood of parturient women with EPH gestosis contained significantly higher concentrations of C3c than in normal parturient women. Complement Bf levels of normal parturient women were lower in the retroplacental blood than in the peripheral. The levels of C4 were significantly decreased and C3c increased in the retroplacental blood of parturient women with EPH gestosis when results were compared with retroplacental blood of normal parturient women. Results of present study suggest that complement activation could contribute to the pathogenesis of EPH gestosis.

Complement C1 Inactivator Proteins↗