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- Ryan, Mary H, et al.
(författare)
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Proteolysis of purified IgGs by human and bacterial enzymes in vitro and the detection of specific proteolytic fragments of endogenous IgG in rheumatoid synovial fluid
- 2008
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Ingår i: Molecular Immunology. - : Elsevier BV. - 1872-9142 .- 0161-5890. ; 45:7, s. 1837-1846
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Tidskriftsartikel (refereegranskat)abstract
- A comparative in vitro survey of physiologically relevant human and microbial proteinases defined a number of enzymes that induced specific hinge domain cleavage in human IgG1. Several of these proteinases have been associated with tumor growth, inflammation, and infection. A majority of the identified proteinases converted IgG to F(ab')(2), and a consistent feature of their action was a transient accumulation of a single-cleaved intermediate (scIgG). The scIgG resulted from the relatively rapid cleavage of the first hinge domain heavy chain, followed by a slower cleavage of the second chain to separate the Fc domain from F(ab')(2). Major sites of enzymatic cleavage were identified or confirmed from the mass of the F(ab')(2) or Fab fragments and/or the amino-terminal amino acid sequence of the Fc for each enzyme including human matrix metalloprotemases (MMPs) 3 and 12, human cathepsin G, human neutrophil elastase (Fab), staphylococcal glutamyl endopeptidase I and streptococcal immunoglobulin-degrading enzyme (Ides). The cleavage sites in IgG1 by MMP-3, cathepsin G and Ides were used to guide the synthesis of peptide analogs containing the corresponding carboxy-termini to be used as immunogens in rabbits. Rabbit antibodies were successfully generated that showed selective binding to different human F(ab')(2)s and other hinge-cleavage fragments, but not to intact IgG. In Western blotting studies of synovial fluids from individuals with rheumatoid arthritis, the rabbit antibodies yielded patterns consistent with the presence of endogenous IgG fragments including F(ab')(2) and the single-cleaved IgG intermediate. The detection in synovial fluid of IgG fragments similar to those observed in the in vitro biochemical studies suggests that proteolysis of IgG may contribute to localized immune dysfunction in inflammatory environments.
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- Svedmark, Per, et al.
(författare)
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Model studies on segmental movement in lumbar spine using a semi-automated program for volume fusion
- 2008
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Ingår i: Journal of Computer-Aided Surgery. - London, UK : Informa Healthcare. - 1092-9088 .- 1097-0150. ; 13:1, s. 14-22
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To validate a new non-invasive CT method for measuring segmental translations in lumbar spine in a phantom using plastic vertebrae with tantalum markers and human vertebrae. Material and Methods: One hundred and four CT volumes were acquired of a phantom incorporating three lumbar vertebrae. Lumbar segmental translation was simulated by altering the position of one vertebra in all three cardinal axes between acquisitions. The CT volumes were combined into 64 case pairs, simulating lumbar segmental movement of up to 3 mm between acquisitions. The relative movement between the vertebrae was evaluated visually and numerically using a volume fusion image post-processing tool. Results were correlated to direct measurements of the phantom. Results: On visual inspection, translation of at least 1 mm or more could be safely detected and correlated with separation between the vertebrae in three dimensions. There were no significant differences between plastic and human vertebrae. Numerically, the accuracy limit for all the CT measurements of the 3D segmental translations was 0.56 mm (median: 0.12; range: -0.76 to +0.49 mm). The accuracy for the sagittal axis was 0.45 mm (median: 0.10; range: -0.46 to +0.62 mm); the accuracy for the coronal axis was 0.46 min (median: 0.09; range: -0.66 to +0.69 mm); and the accuracy for the axial axis was 0.45 mm (median: 0.05; range: -0.72 to +0.62 mm). The repeatability, calculated over 10 cases, was 0.35 mm (median: 0.16; range: -0.26 to +0.30 mm). Conclusion: The accuracy of this non-invasive method is better than that of current routine methods for detecting segmental movements. The method allows both visual and numerical evaluation of such movements. Further studies are needed to validate this method in patients.
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