Biomaterial Database

Mechanism of complement activation by radiographic contrast media. 1977

C M Arroyave, and E M Tan

Activation of the complement system by radiographic contrast media (RCM) was demonstrated by in vitro haemolytic and immunological assays. Such activation was found to be a function of the RCM molar concentration. Iodipamide was the most active of five RCM tested. When RCM was incubated with normal human serum (NHS) in the presence of ethylene glycol-tetra-acetic acid and magnesium ions, conditions which block activation of the classical pathway but permit activation of the alternative pathway, haemolytically active C3, properdin and factor B were found to be decreased but haemolytically active C4 was normal. Using counterimmunoelectrophoresis, the activation of complement was further demonstrated by detection of C3 and factor B-split products. Finally, when radiolabelled complement proteins were reacted with RCM in vitro and studied by density-gradient ultracentrifugation, it was demonstrated that a large complex was formed with a sedimentation of 22S, similar in characteristics to the C5b-C9 complex. It was postulated that the mechanisms of in vitro consumption of complement by RCM was mainly through the alternative pathway.

UI	MeSH Term	Description	Entries
D011414	Properdin	A 53-kDa protein that is a positive regulator of the alternate pathway of complement activation (COMPLEMENT ACTIVATION PATHWAY, ALTERNATIVE). It stabilizes the ALTERNATIVE PATHWAY C3 CONVERTASE (C3bBb) and protects it from rapid inactivation, thus facilitating the cascade of COMPLEMENT ACTIVATION and the formation of MEMBRANE ATTACK COMPLEX. Individuals with mutation in the PFC gene exhibit properdin deficiency and have a high susceptibility to infections.	Complement Factor P,Factor P, Complement
D003165	Complement System Proteins	Serum glycoproteins participating in the host defense mechanism of COMPLEMENT ACTIVATION that creates the COMPLEMENT MEMBRANE ATTACK COMPLEX. Included are glycoproteins in the various pathways of complement activation (CLASSICAL COMPLEMENT PATHWAY; ALTERNATIVE COMPLEMENT PATHWAY; and LECTIN COMPLEMENT PATHWAY).	Complement Proteins,Complement,Complement Protein,Hemolytic Complement,Complement, Hemolytic,Protein, Complement,Proteins, Complement,Proteins, Complement System
D003176	Complement C3	A glycoprotein that is central in both the classical and the alternative pathway of COMPLEMENT ACTIVATION. C3 can be cleaved into COMPLEMENT C3A and COMPLEMENT C3B, spontaneously at low level or by C3 CONVERTASE at high level. The smaller fragment C3a is an ANAPHYLATOXIN and mediator of local inflammatory process. The larger fragment C3b binds with C3 convertase to form C5 convertase.	C3 Complement,C3 Precursor,Complement 3,Complement C3 Precursor,Complement Component 3,Precursor-Complement 3,Pro-C3,Pro-Complement 3,C3 Precursor, Complement,C3, Complement,Complement, C3,Component 3, Complement,Precursor Complement 3,Precursor, C3,Precursor, Complement C3,Pro C3,Pro Complement 3
D003287	Contrast Media	Substances used to allow enhanced visualization of tissues.	Radiopaque Media,Contrast Agent,Contrast Agents,Contrast Material,Contrast Materials,Radiocontrast Agent,Radiocontrast Agents,Radiocontrast Media,Agent, Contrast,Agent, Radiocontrast,Agents, Contrast,Agents, Radiocontrast,Material, Contrast,Materials, Contrast,Media, Contrast,Media, Radiocontrast,Media, Radiopaque
D003378	Counterimmunoelectrophoresis	Immunoelectrophoresis in which immunoprecipitation occurs when antigen at the cathode is caused to migrate in an electric field through a suitable medium of diffusion against a stream of antibody migrating from the anode as a result of endosmotic flow.	Electrosyneresis,Immunoelectroosmophoresis,Immunoelectrophoresis, Countercurrent,Immunoelectrophoresis, Crossover,Countercurrent Immunoelectrophoresis,Crossover Immunoelectrophoresis
D004305	Dose-Response Relationship, Drug	The relationship between the dose of an administered drug and the response of the organism to the drug.	Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D066298	In Vitro Techniques	Methods to study reactions or processes taking place in an artificial environment outside the living organism.	In Vitro Test,In Vitro Testing,In Vitro Tests,In Vitro as Topic,In Vitro,In Vitro Technique,In Vitro Testings,Technique, In Vitro,Techniques, In Vitro,Test, In Vitro,Testing, In Vitro,Testings, In Vitro,Tests, In Vitro,Vitro Testing, In