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PubMed1979

Complement and contrast material reactors.

Patients showing systemic reactions to intravascular contrast media and patients receiving contrast media without reaction have significantly different mean values (p is less than 0.05) for functionally determined serum C1-esterase inhibitor (C1 INH) and total hemolytic complement (CH50). The lower concentration of these components in reactors appears in baseline serum samples (as well as after injection), and suggests that many anaphylactoid reactions to contrast media are conditioned by earlier complement consumption, and result directly from contrast-induced activation of complement, and other activation system components in the presence of inhibitor depression.

Complement C1 Inactivator Proteins↗
PubMed1975

Serum-induced inhibition of isotonic fluid absorption by the kidney proximal tubule. III. Further evidence that complement-mediated cell lysis is involved.

The results of our previous studies have suggested that serum-induced inhibition of proximal tubular fluid absorption is due to complement-induced lysis of the tubular cells. The present study provides further evidence in support of this idea as well as other information pertinent to the mechanism of complement activation in vivo. 1. The electrical resistance of the luminal brush border membrane is reduced drastically concomitantly with a drop in cell potential difference when serum is perfused intraluminally. 2. Human C1 inhibitor (30-50 units/ml) does not significantly affect the inhibitory activity of human serum on fluid absorption, suggesting the non-involvement of the classical pathway. 3. Reactive lysis reagents (C56, C7, C8 + C9) partially inhibit fluid absorption when infused into the lumen. 4. In contrast to our previous report (Sato, K. and Ullrich, K.J. (1974) Biochim. Biophys. Acta 354, 182-187), very fresh serum, 10-times diluted can inhibit fluid absorption if perfused for 10 min. 5. Both mouse and guinea pig serum, which are normally inactive, are activated to attack the tubular cells if 1/100 volume rat or rabbit serum is added to them No such activation occurs by mixing guinea pig serum and mouse serum. The available data suggest that the presence of the later complement components but not the heat-labile factor (Factor B) or C3PA or C1 in the added serum is a prerequisite for mouse and guinea pig sera to be activated to inhibit fluid absorption.

Animals↗
PubMed1976

C1 inactivator.

Explore the source record for details and available documents.

Amino Acids↗
PubMed1978

Inhibition of four human serine proteases by substituted benzamidines.

A series of substituted benzamidines has been examined for their inhibitory activity against the human serine proteases--trypsin, thrombin, plasmin, and C1s, a subunit of the first component of complement. The inhibition constants obtained for each enzyme were correlated with physical-chemical properties of the substituent group using the quantitative structure-activity relationship approach. This analysis indicated that plasmin and C1s are very similar in their interactions with substituted benzamidines. The binding of benzamidines in both enzymes was affected by electron donation from the substituent and its hydrophobicity. Thrombin-benzamidine interaction was affected only by the hydrophobicity of the substituent. Trypsin displayed a complex interaction with substituted benzamidines, and interaction was dependent on molar refractivity and molecular weight. Certain substituents deviated significantly from the interactions predicted by the analysis. These compounds, the (m- and p-amidinophenyl)pyruvic acids, when analyzed by computer modeling, suggested that direct interaction between the substituent and the enzyme surface is important in assessing the effect of substituent groups on inhibitory activity.

Amidines↗
PubMed1976

Irreversible enzyme inhibitors. Inhibitors of guinea pig complement derived by quaternization of substituted pyridines with benzyl halides.

A series of 83 compounds derived from hydrocarbon-substituted pyridines by quaternization with PhCH2Br usually containing a 2-SO2F or 6-Cl-2-SO2F group was synthesized and evaluated as inhibitors of guinea pig complement and in most cases its C1 component. The most active compounds were 3-(4-phenylphenylbutyl)-N-(6-choro-2-fluorosulfonylbenzyl) pyridinium bromide (43) and 3-(4-phenylphenylbutyl)-N-(2-fluorosulfonylbenzyl) pyridinium bromide (44), each showing 50% inhibition at 7.8 muM. The most effective irreversible inhibitor of the C1 component was N-(6-chloro-2-fluorosulfonylbenzyl)-5,6-benzoquinolinium bromide (87), which showed 50% inhibition at 4 muM.

Animals↗
PubMed1977

Inhibition of the reconstitution of the haemolytic activity of the first component of human complement by a pepsin-derived fragment of subcomponent C1q.

1. A fragment of subcomponent C1q, which contained all the collagen-like features present in the intact molecule, was isolated by pepsin digestion as described by Reid [Biochem. J. (1976) 155, 5-17]. 2. The pepsin-derived fragment of subcomponent C1q did not bind to antibody-coated erythrocytes under conditions where complete binding of sub-component C1q took place. 3. The peptic fragment blocked the reconstitution of C1 haemolytic activity by competing with intact subcomponent C1q in the utilization of a mixture of the other two subcomponents, C1r and C1s. 4. Reduction and alkylation of the interchain disulphide bonds in the pepsin fragment did not markedly affect its inhibitory effect, whereas heating at 56 degrees C for 30min completely abolished the effect. 5. Lathyritic rat skin collagen and CNBr-derived peptides of pig type II collagen showed no ability to mimic the inhibitory effect of the pepsin fragment when tested over the same concentration range as used for the peptic fragment. 6. The peptic fragment was unable to block efficiently the reconstitution of C1 haemolytic activity unless it was added to the mixture of subcomponents C1r and C1s before the attempt to reconstitute C1 haemolytic activity, in solution, or on the surface of antibody-coated erythrocytes. 7. Evidence was obtained that suggested that subcomponent C1q bound the subcomponent C1r-C1s complex more efficiently when the subcomponent C1q was bound to antibody than when it was free in solution.

Binding Sites, Antibody↗
PubMed1976

Treatment of hereditary angioedema with danazol. Reversal of clinical and biochemical abnormalities.

Danazol, an androgen derivative, was evaluated for its effectiveness in preventing attacks of hereditary angioedema in a double-blind study with nine patients. Of 47 placebo courses, 44 ended with attacks, but during 46 danazol courses only one attack occurred. Side effects were minimal, and virilization was not observed in the women studied. C1 esterase inhibitor levels increased three to four times, and levels of the fourth component of complement (C4) increased 15 times. These changes began during the first day of therapy and were maximal by one to two weeks. After therapy was stopped, C1 esterase inhibitor and C4 levels rapidly decreased. Danazol effectively prevents attacks in hereditary angioedema and acts to correct the underlying biochemical abnormality.

Adult↗
PubMed1979

Hereditary angio-oedema: treatment with danazol. Report of a case.

An 8-year-old boy with hereditary angio-oedema was treated with danazol under close endocrinological supervision. The boy's C1 esterase inhibitor (C1inh) and C4 levels increased rapidly to near normal values under a daily dose of 400 mg and were maintained at about 50% of the normal by maintenance doses of 200 mg danazol every other day. Throughout the entire treatment period (11 months) the boy has been maintained free from attacks of angio-oedema. No hormonal imbalance was detected in the follow-up period. Our results indicate that danazol should be suitable for the treatment of HAE not only in adults but also in prepubescent children.

Angioedema↗
PubMed1979

Complement abnormalities in diffuse plane xanthomatosis with paraproteinaemia.

Paraproteinaemia may be associated with xanthomatous skin deposits and these can arise in the absence of elevated lipid levels. Two cases of benign monoclonal gammopathy with diffuse plane xanthomatosis are reported. Case 1 exhibited hypolipidaemia and a functional deficiency of C1 esterase inhibitor. Case 2 showed a normal lipoprotein profile, abnormal platelet aggregation, and a cutaneous vasculitis with evidence of complement consumption via the classical pathway. The significance of these abnormalities is discussed.

Aged↗
PubMed1977

Haemostatic and complement changes in a family with 'allergic' disorders.

A family with allergic manifestations, haemostatic disturbances, total absence of haemolytic activity of the complement system and low IgG levels is described. It is suggested that this functional abnormality of the complement system and the decreased level of immunoglobulin G may be due to immune complex reactions.

Adolescent↗
PubMed1979

Hereditary complement (C2) deficiency with discoid lupus erythematosus and idiopathic atrophoderma.

A family with hereditary deficiency of the second component of complement was studied. Three siblings were homozygous for C2 deficiency and two of them had associated skin diseases. One sister presented with idiopathic atrophoderma and the other had clinical and pathological manifestations of discoid lupus erythematosus. This is the first description of an association between idiopathic atrophoderma and C2 deficient state.

Adolescent↗