PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 458054

Complement and contrast material reactors.

E C Lasser·J H Lang·S G Lyon·A E Hamblin
View original source ↗Export metadata ↓

Abstract

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.

Explore related subjects

Complement C1 Inactivator ProteinsComplement System ProteinsContrast MediaHemolysisHumansHypersensitivityJournal ArticleResearch Support, U.S. Gov't, P.H.S.

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

E C Lasser, J H Lang, S G Lyon, A E Hamblin. 1979. Complement and contrast material reactors.. https://doi.org/10.1016/0091-6749(79)90043-5

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1992

Secondary structure changes stabilize the reactive-centre cleaved form of SERPINs. A study by 1H nuclear magnetic resonance and Fourier transform infrared spectroscopy.

Proteinase inhibitor members of the SERPIN superfamily are characterized by the presence of a proteolytically sensitive reactive-site loop. Cleavage within this region results in a conformational transition from an unstable "stressed" native protein to a more stable "relaxed" cleaved molecule. In order to identify the principal molecular aspects of this transition, 1H nuclear magnetic resonance (n.m.r.) and FT-IR spectroscopy were applied to the study of four SERPINs. 1H n.m.r. spectra of approximately 20 high-field ring-current-shifted methyl signals exhibited slightly different chemical shifts in the native and cleaved forms of alpha 1-antitrypsin (alpha 1-AT), alpha 1-antichymotrypsin (alpha 1-ACT) and C1 inhibitor (C1-INH), but not ovalbumin, between 20 degrees C and 90 degrees C. Ring current calculations based on crystal co-ordinates for cleaved alpha 1-AT and alpha 1-ACT and native ovalbumin showed that these signals originate from highly localized interactions between different buried residues corresponding to alpha-helix and beta-sheet segments of the SERPIN fold. The small shift changes correspond to small relative conformational side-chain rearrangements of about 0.01 nm to 0.05 nm in the protein hydrophobic core, i.e. the tertiary structure interactions in the two forms of the SERPIN fold are well-preserved, and changes in this appear unimportant for the stabilization found after reactive centre cleavage. Fourier transform infrared (FT-IR) spectroscopic studies of the amide I band showed that the native and cleaved forms of alpha 1-AT, alpha 1-ACT and C1-INH contain 28% to 36% alpha-helix and 38% to 44% beta-sheet. Second derivative FT-IR spectra using H2O and 2H2O buffers revealed very large differences in the amide I band between the native and cleaved forms of alpha 1-AT, alpha 1-ACT and C1-INH, but not for ovalbumin. The alpha-helix band was most sensitive to 1H-2H exchange, while the beta-sheet bands were not, and greater amounts of antiparallel beta-sheet were detected in the cleaved form. 1H n.m.r. showed that polypeptide amide 1H-2H exchange was greater in the native forms of alpha 1-AT, alpha 1-ACT and C1-INH than in their cleaved forms, whereas for ovalbumin it was unchanged. The FT-IR and 1H-2H exchange data show that alterations in the secondary structure are central to the stabilization of the cleaved SERPIN structure.(ABSTRACT TRUNCATED AT 400 WORDS)

Complement C1 Inactivator Proteins↗
PubMed1992

[Functional determination of C1-inhibitors in human blood].

The author describes the method of assessment of the C1-inhibitor, the principle being activation of plasma prekallikrein by Hageman factor fragment (HFf) to the active enzyme kallikrein which splits the specific chromogenic substrate NO-Pro-Phe-Arg-pNA. In the presence of acetone the influence of C1-INH is eliminated and the assessed amount of kallikrein corresponds to the prekallikrein plasma level. In a parallel estimation without acetone after formation of the C1-INH complex the residual amount of kallikrein is assessed. The difference between the two levels is proportional to the formed enzyme-inhibitor complex. The method was tested on plasma of healthy donors and the results were compared with assessment of C1-INH by a modification of Schapira's method (6) (correlation coefficient r = 0.88) and with Cullmann's method (8) (r = 0.61). The advantage of the proposed method is that it does not require commercially unavailable enzyme preparations, that it uses as activating agent HFf concentrate, prepared in the laboratory and that along with the C1-INH level also the plasma level of prekallikrein is assessed.

Complement C1 Inactivator Proteins↗