Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024141 (systemic lupus erythematosus)
 44,322 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The electrophoretic mobility of properdin in agarose with and without EDTA examined in sera from normal subjects and from patients with mesangiocapillary glomerulonephritis, systemic lupus erythematosus, rapidly progressive glomerulonephritis, mesangial IgG-IgA disease, minimal change glomerulonephritis and partial lipodystrophy. In 'EDTA agarose", the properdin arc of normal serum was always cathodal (gamma), whereas in non-EDTA agarose it was always (beta), indicating that agarose activated properdin with its consequent conversion from a cathodal to an anodal form. Using this change in the mobility of properdin to investigate activation of the properdin system, it was found that the lower the C3 concentration of diseased sera, the less able were they to support properdin conversion by non-EDTA agarose. This relationship we interpret as a manifestation of the requirement of an intact C3b feedback pathway for properdin activation. This view was supported experimentally by (i) decreasing ability of non-EDTA agarose to shift properdin mobility in normal serum as it was progressively depleted of components of the alternative pathway by cobra venom factor, C3 nehritic factor or Mg2+, and (ii) the inability of non-EDTA agarose to shift properdin in sera depleted of C3 or factor B, and in serum deficient in C3. The report of other workers that activated properdin causes generation of C3b, coupled with our finding that properdin activation depends on the C3b feedback, indicates that a system exists in which activation of the C3b feedback cycle allows activation of properdin, allowing in turn further amplification of the C3b feedback. That the anodal form of properdin may be a property of activated properdin was shown by our observations that properdin eluted from zymosan was anodal and activated, and that the properdin in the supernatant normal serum incubated with inulin was anodal.
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PMID:Mechanisms of activation of the properdin system. Studies on properdin electrophoretic mobility in agarose activation of the alternative pathway. 81 32

Recently many studies have been done to identify complement pathway activation in renal tissue from patients with renal disease. We examined whether tissues obtained by renal biopsy from such patients would fix guinea pig complement. Nine out of 15 patients with systemic lupus erythematosus (SLE), 4 out of 7 patients with mesangiocapillary glomerulonephritis (MCGN), and 2 out of 7 cases with acute glomerulonephritis (AGN) fixed guinea pig C3. We found that tissues from 5 out of 9 guinea pig C3-positive SLE cases fixed guinea pig C4, while none of the guinea pig C3-positive tissues from patients with MCGN or AGN fixed guinea pig C4. These guinea pig C3-positive renal tissues were further studied for interaction with C4-deficient guinea pig serum, EDTA guinea pig serum, heated guinea pig serum, and EGTA Mg2+ guinea pig serum. The results indicated that activation of both the alternate and classical complement pathways occurred with tissues from patients with SLE, while activation of the alternate pathway occurred with MCGN and AGN. Results for tissues from AGN and MCGN patients indicated the presence of C3 convertase and protease which interacted with guinea pig C3.
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PMID:Guinea pig complement fixation by tissues from hypocomplementaemic renal diseases. 351 34

Immunoglobulins, containing antibodies against U1-snRNP, have been prepared from a patient with systemic lupus erythematosus. After coupling these antibodies to a Sepharose matrix, U-snRNPs have been isolated and purified from rat liver nuclei by use of immunoaffinity chromatography. The resulting RNPs had the typical protein pattern of U-sn RNPs and a sedimentation coefficient of 12 S. The U-snRNP preparation was associated with an endoribonuclease which required Mg2+ for optimal activity. The enzyme, with an pH optimum of 6.2, degraded only poly(U). Other single-stranded polyribo- and polydeoxyribonucleotides, tRNA, as well as double-stranded RNA and DNA were not digested. The products of a terminal digestion are (U)6-12 with 3'-OH and 5'-P termini. The possible involvement of this endoribonuclease in the splicing of hnRNA is discussed.
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PMID:Association of a polyuridylate-specific endoribonuclease with small nuclear ribonucleo-proteins which had been isolated by affinity chromatography using antibodies from a patient with systemic lupus erythematosus. 622 85

Activation of the alternative pathway of human complement (C) by soluble C activators resulted in a decrease of C9 antigen, measured by single radial immunodiffusion, concomitant with a decrease of C9 hemolytic activity. In the presence of ethylene glycol bis-(beta-aminoethylether)-tetraacetic acid (EGTA) and Mg2+, this decrease of C9 antigen in the presence of soluble activators such as dinitrophenylated bovine serum albumin depends mainly on the activation of the alternative C pathway. Therefore, an assay system to express the total activity of the alternative C pathway in human serum - the C9 depletion test (C9DT) -, was devised. C9DT showed significantly lower values for patients with systemic lupus erythematosus and rheumatoid arthritis than for control patients.
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PMID:An immunochemical method for assessing the function of the alternative complement pathway. 646 88

Properties of low Mg2+ induced epileptiform activity were studied in isolated rat hippocampal slices or in combined slices containing the entorhinal cortex and hippocampus. Slices were prepared from rats which were 1, 2, 3 or more weeks of age. Field potentials and often also changes in [K+]0, [Ca2+]0 and [Mg2+]0 were recorded with appropriate ion selective microelectrodes. In isolated hippocampal and entorhinal cortex/hippocampal combined slices the latency to onset of epileptiform activity upon lowering of extracellular Mg2+ was shortest in the youngest age group and approached adult levels at about the fourth postnatal week. Washout kinetics of Mg2+ were fastest in slices from 1-week-old rats. The onset of low Mg2+ induced epileptiform activity occurred at higher Mg2+ levels in slices from young compared with those from adult animals. In isolated hippocampal slices the epileptiform discharges varied in appearance during development. Short discharges lasting for 40 to 80 ms were observed in hippocampal slices prepared from 1-week-old and adult animals. Seizure-like events (SLE's) characterized by slow negative potential shifts and characteristic elevations in [K +]0 and decreases in [Ca2+]0 lasting for up to 30 s were observed in a proportion of hippocampal slices prepared after the first, second and third postnatal week. In slices from week 2 and 3 seizure-like events often progressed into spreading depressions (SD's). In entorhinal cortex/hippocampal combined slices seizure-like events were observed in all age groups. The seizure-like events spread readily into dentate gyrus (DG), area CA3 and CA1 after week 1.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Properties of low Mg2+ induced epileptiform activity in rat hippocampal and entorhinal cortex slices during adolescence. 758 96

Experiments and hydrolysis of substrates with known spatial structures (such as yeast tRNAPhe, as well as normal and mutant tRNALys from human mitochondria produced by transcription of the appropriate DNA species, that is, RNA genes) were performed to study the ribonuclease activity of antibodies isolated from blood sera of patients with systemic lupus erythematosus (SLE). The antibody preparations contained two types of ribonuclease activities: the first corresponded to the specificity of ribonuclease A and was found during hydrolysis at low salt concentrations, whereas the second was stimulated by Mg2+ and displayed unique specificity toward double-stranded regions of the substrate. The possible use of the antibody preparations as tools for structural studies of conformational differences between RNA molecules was examined. In experiments with unmodified and mutant tRNALys species differing in one base found in the T-loop, we found that hydrolysis with SLE antibodies can detect small local structural changes in RNA under physiological conditions.
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PMID:RNA-hydrolyzing antibodies from peripheral blood of patients with lupus erythematosus. 927 87

The structural and functional integrity of the cell is largely maintained by protein-protein interactions. Recently, we demonstrated that multiple antigenic peptides (MAPs) constructed from 60 kDa Ro sequence could be used to show intramolecular and intermolecular protein-protein interaction within the 60 kDa Ro ribonucleoprotein particle. We were interested in understanding the mechanism of this binding and hypothesized that this interaction might be mediated through divalent metal ions. The 60 kDa Ro-MAPs failed to interact with purified 60 kDa Ro in the presence of EDTA or EGTA when analyzed by Ouchterlony or surface plasmon resonance (SPR) analysis. When purified 60 kDa Ro was incubated with various metal ions such as Cu2+, Mg2+, Zn2+ and Ca2+, and analyzed by Ouchterlony or SPR for binding to specific 60 kDa Ro-MAPs only Ca2+ ions significantly increased the binding. It was interesting to note that recombinant 60 kDa Ro formed precipitin lines with Ro-MAPs only in the presence of Ca2+ ions. Anti-Ro60 containing SLE sera bound to recombinant Ro60 strongly when incubated in the presence of Ca2+ ions but not in the absence of Ca2+ ions. Using SPR analysis we also found that native Ro60 binds to La only in the presence of Ca2+. These data imply that Ca2+ induces a more native tertiary structure to recombinant 60 kDa Ro and makes it more antigenic. Thus, the observed intramolecular and intermolecular interactions and antigen-antibody interactions could be Ca2+ ion mediated conformational interactions, and we propose that 60 kDa Ro is a calcium binding protein.
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PMID:Interaction of calcium and Ro60: increase of antigenicity. 1523 60