The activity in human serum which is responsible for conversion of C3 proactivator (C3PA) to C3 activator was shown to reside in a 3S alpha-globulin. The factor, called C3PA convertase (C3PAse), was obtained in partially purified form. For conversion of C3PA, C3PAse required participation of metal ions and of a C3 fragment, which in physicochemical and antigenic properties resembled C3b. Isolat...

C3 exhibits two common allotypic variants that may be separated by gel electrophoresis and are called C3 fast (C3 F) and C3 slow (C3 S) . C3 F, the less common variant, occurs at appreciable frequencies only in Caucasoid populations (gene frequency = 0.20) . An increased prevalence of the C3 F allele has been reported in patients with partial lipodystrophy, IgA nephropathy, and Indian childhood...

OBJECTIVE To verify the clinical outcomes of posterior C2-C3 fixation for unstable Hangman's fracture compared with posterior C1-C3 fixation. METHODS Twenty four patients for unstable Hangman's fracture were enrolled between July 2007 and June 2010 in this study. Thirteen patients underwent posterior C2-C3 fusion and 11 patients underwent posterior C1-C3 fusion. Clinical outcomes were evaluat...

BACKGROUND We previously demonstrated that vascular injury-induced neointima formation is exaggerated in human C-reactive protein (CRP) transgenic (CRPtg) compared to nontransgenic (NTG) mice. We now test the hypothesis that complement is required for this effect. METHODS AND RESULTS CRPtg and NTG with a normal complement system versus their counterparts lacking expression of complement compo...

The intricate system of serum complement proteins provides resistance to infection. A pivotal step in the complement pathway is the assembly of a C3 convertase, which digests the C3 complement component to form microbial binding C3 fragments recognized by leukocytes. The spleen and C3 provide resistance against blood-borne S. pneumoniae infection. To better understand the mechanisms involved, w...