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Biomedical subjects

I Gigli

Publications and source records attributed to I Gigli.

At least 127 records · Page 7Linked to original sources
PubMed1971

Modulation of function of the activated first component of complement by a fragment derived from serum. I. Effect on early components of complement.

An activity designated Kf can be separated from human serum and shown to give a 100-300% enhancement in the hemolytic activity of fully activated, fractionated C1. The enhancement of C1 activity is not because of activation of precursor C1 and it is not attributable to an effect on C1 binding. EAC42 or EAC4 intermediates interacted with C1Kf exhibit a greater T(max) and shorter Z(max) than when such intermediates are reacted with the same number of hemolytic units of C1. C3 consumption by the EAC1Kf42 intermediate greatly exceeds that of the EAC142 intermediate produced from the same EAC4 cells by comparable inputs of the other two complement components. Taken together, these findings suggest that Kf-treated C1 achieves more efficient utilization of C4 and C2 to create a larger number of 42 sites as appreciated on the intermediates by shorter T(max) and a greater Z(max), and an increased capacity to utilize C3. The capacity of Kf to enhance C1 upon introduction into whole serum of a patient with hereditary angioedema (HAE) in a manner comparable to its effect on fractionated C1 suggests that the effect of Kf may be pertinent to certain pathophysiologic conditions of man.

Angioedema↗
PubMed1969

Fluid phase destruction of C2hu by C1hu. II. Unmasking by C4ihu of C1hu specificity for C2hu.

It has been demonstrated that C1 isolated in the unactivated form fails to inactivate C4 or C2 in the fluid phase, while the activated molecule, C1 rapidly converts C4 to hemolytically inactive C4i, but does not efficiently inactivate C2. The production and presence of C4i now confers on C1 the ability to rapidly inactivate C2. After heating at 56 degrees C, so as to destroy the hemolytic activity, heat inactivated C1 is still capable of inactivating C4 but the presence of C4i no longer confers an ability to inactivate C2. Studies with the subunits of C1-C1q, C1r, C1s, indicate that the action of C1s on C2 can be inhibited by C1r and that this inhibition is reversed by the presence of homologous C4. These studies indicate that the interaction of C4i with a heat labile receptor conformation in C1 uncovers a masked specificity for C2.

Animals↗
PubMed1969

Fluid phase destruction of C2hu by C1hu. I. Its enhancement and inhibition by homologous and heterologous C4.

The fluid phase inactivation of C2(hu) by C1(hu) is markedly enhanced by the presence of C4(hu). The enhancement is afforded by C1 inactivated C4(hu), namely C4i(hu), and requires the simultaneous presence of enzymatically active C1. Heterologous C4 of guinea pig origin protects C2(hu) from the inactivation by C1(hu). Thus, in both the fluid phase and on the cellular intermediate, C4(hu) is essential to the specific action of C1(hu) on C2(hu). It is possible that C4i alters C2 so as to present a more suitable substrate to the C1 enzyme or that C4i acts on the C1 to uncover a specificity for native C2.

Animals↗