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M Digeon

Publications and source records attributed to M Digeon.

At least 19 recordsLinked to original sources
PubMed1982

Analysis of circulating IgA and detection of immune complexes in primary IgA nephropathy.

The sera of 31 patients with primary IgA nephropathy were investigated for IgA containing immune complexes by Raji cell-binding IgA radioimmunoassay and conglutinin-binding IgA radioimmunoassay. Positive results, without correlation with IgA serum levels, were found in 68% of the patients using the first assay, in 39% of the patients with the second assay. Positive sera were analysed by gel chromatography. Conglutinin-binding IgA eluted in two peaks, a minor one of 400,000-800,000 daltons mol. wt and a major one corresponding to monomeric IgA. No increase of secretory IgA and of polymeric IgA was detectable. IgA immune complexes were likewise found in the sera of patients with systemic lupus (five of 12), rheumatoid arthritis (four of 12), subacute bacterial endocarditis (four of 12) and HB virus hepatitis (four of 16). However, the high prevalence on these sera of IgG and IgM immune complexes detected by polyethylene glycol precipitation, solid phase Clq binding assay contrasted strongly with their absence in IgA nephropathy. In addition, the presence of abnormal amounts of conglutinin reactive IgA correlated with the recurrence of IgA deposits after renal transplantation (20 patients studied). Conglutinin reactive IgA could contribute to the glomerular deposition of IgA and subsequently play a significant role in the pathogenesis of IgA nephropathy.

Antigen-Antibody Complex↗
PubMed1980

Hepatitis B antigen-associated periarteritis nodosa in patients undergoing long-term hemodialysis.

Periarteritis nodosa was observed in three of 266 persistent hepatitis B antigen (HBsAg) carriers undergoing long-term hemodialysis; no cases of necrotizing vasculitis occurred among 384 other patients undergoing dialysis having either no or transient antigenemia. Circulating e antigen, but no e antibody, was found in two of these three patients. The serum level of the third component of complement (C3) was normal in two patients and low in the third. Circulating immune complexes were demonstrated in all three patients, using polyethylene-glycol (PEG) precipitation, PEG-C4, and solid phase C1q tests. HBsAg and anti-hepatitis B antibody (HBsAb) were identified in the PEG precipitates using radioimmunoassay and electron microscopy technics. Direct immunofluorescence performed on a muscle biopsy specimen from one patient was positive for HBsAg, but not for immunoglobulin G (IgG), immunoglobulin M (IgM), C3 or C1q. These data support the hypothesis that circulating immune complexes involving HBsAg may be involved in the pathogenesis of periarteritis nodosa.

Antigen-Antibody Complex↗
PubMed1979

Fate of circulating immune complexes in infective endocarditis.

To examine the role of circulating immune complexes (CIC) in infective endocarditis, we studied 64 patients with infective endocarditis for the presence of CIC by the polyethylene-glycol (PEG)-precipitation test and the Clq binding test. This study was repeated during the course of the disease in 23 patients. CIC were found in 84 per cent of patients (66 per cent with acute infective endocarditis, 89 per cent with subacute infective endocarditis) during the active phase of the disease. Higer PEG precipitates were associated with typical cutaneous signs, cryoglobulins and nonstreptococcic culture-positive infective endocarditis. Under appropriate antibiotic treatment, the PEG precipitate levels of 17 patients fell within 1 month to the normal range, with a concomitant drop in cryoglobulinemia and rheumatoid factor. Conversely, uncontrolled sepsis always (six of six) yielded a rising level of CIC. These findings support the hypothesis that CIC may be important in the pathogenesis of peripheral lesions in infective endocarditis.

Adolescent↗
PubMed1979

The role of circulating immune complexes in the glomerular disease of experimental hepatosplenic schistosomiasis.

The serological and renal changes were studied simultaneously in 115 mice infected with Schistosoma mansoni. IgG and IgM, but not IgA anti-S. mansoni antibodies were detected in the sera, together with circulating immune complexes containing schistosomal antigen. Glomerular mesangial deposits of IgA, IgM and C3 were observed. Despite the strong correlation observed between the occurrence of the circulating immune complexes containing schistosomal antigen and the glomerular deposits, results concerning the behaviour of IgA suggest that portal hypertension and liver damage have a role in the pathogenesis of glomerular lesions.

Animals↗
PubMed1977

[Detection of circulating immune complexes by three techniques using polyethylene glycol (author's transl)].

The search for circulating immune complexes (IC) by precipitation tests using polyethylene glycole was performed in a large series of normal (150 subjects) and 1200 pathological sera (over 800 patients). Increased precipitability of IgG and C4 was seen in a great percentage (80%) of pathological sera giving positive PEG precipitation without direct influence of IgG, IgM, C1q, C3 and C4 serum levels. The labeled C1q binding test gave similar results in 90 normal and 640 pathological sera. The C1q binding test could be replaced by the more direct and simple evaluation of the amount of C4 precipitated with IgG by 3.5% PEG. Positive results obtained in the three methods were particularly found in patients with diseases generally presumed to represent immune complexes diseases including acute glomerulonephritis, systemic lupus erythematosus, polyarteritis nodosa, subacute bacterial endocarditis, and acute or chronic hepatitis.

Antigen-Antibody Complex↗
PubMed1977

Detection of circulating immune complexes in human sera by simplified assays with polyethylene glycol.

The search for circulating immune complexes by precipitation tests using polyethylene glycol (PEG) was performed on a series of normal and pathological sera. Various factors affecting PEG precipitation were studied. Immunoglobulins and complement factors percipitated by PEG (3.5%) were quantified and their significance was discussed in relation to serum levels. The PEG test was compared to labeled C1q binding test with a fairly good correlation. The direct evaluation of the amount of C4 precipitated with IgG by 3% PEG (C4 test) provided a simpler routine assay than the C1q binding test for detecting complement-fixing immune complexes. The direct PEG test and the C4 tests gave positive results in patients with diseases generally presumed to be associated with immune complexes including systemic lupus erythematosus, acute glomerulonephritis, bacterial sub-acute endocarditis and chronic acitve hepatitis. The demonstration of HBs antigen and antibody after acid dissociation of PEG precipitates from hepatitis B seronegative sera illustrated the fact that PEG does precipitate and thus concentrates circulating immune complexes.

Adult↗
PubMed1977

Detection of hepatitis B antigen in circulating immune complexes in acute and chronic hepatitis.

By using polyethylene glycol precipitation at low concentration (PEG test) and the radiolabeled C1q binding test, immune complexes were detected sera from acute (23/28) and chronic (28/32) hepatitis patients, hemodialyzed patients with chronic hepatitis B surface (HBs) antigenemia (7/19), and asymptomatic HBs antigen carriers (2/11). After treatment of PEG precipitates with acidic pH, heating, or proteolytic enzyme (protease), electroimmunodiffusion or radioimmunoassay revealed the presence of HBs antigen or antibody in dissociated immune complexes in sera from several acute and chronic hepatitis patients. Electron microscopy showed immune complexes of HB virus in 9 of 12 PEG precipitates obtained from PEG-test-positive sera; these 9 precipitates were from patients with acute or chronic hepatitis and the other three from chronic HBs Ag carriers. Free HB virus particles were observed after protease digestion of PEG precipitates. Neither immune complexes nor virus particles were seen in precipitates from PEG-test-negative but HBs-Ag-positive sera from chronic carriers.

Acute Disease↗
PubMed1975

[Immunologic study of subacute infectious endocarditis through the search for circulating immune complexes. Preliminary results apropos of 13 cases].

The detection of circulating immune complexes by precipitation by polyethylene glycol represents a valuable technique of study in sub-acute bacterial endocarditis. In a series of 13 patients, this measurement was carried out, confirming the quasi-constant presence of circulating immune complexes in active S.B.E. This might be of diagnostic value in forms with negative blood culture and, further, make it possible, subsequently, to find the antigen responsible by dissociation of the circulating immune complexes.

Adult↗
PubMed1975

Some immunochemical and chemical aspects of S and R Shigella dysenteriae 1 endotoxins.

Endotoxins of S and R forms of Shigella dysenteriae 1 were prepared by NaCl-Na citrate extraction, purified by gel chromatography on Sephadex G 200 and on Sepharose 4B and subjected to immunochemical and chemical analysis. The toxins contained 25--30% of lipids, 40--50% of carbohydrates and 14--24% of protein. The lipid and protein moieties of the lipopolysaccharide-protein complexes exhibited no significant difference, whereas the sugar moieties differed markedly (both qualitatively and quantitatively), in relation to the growth form of the culture. The lipid moiety, which consists at least of 22 fatty acids, has the greatest relative content (approx. 50%) of behenic acid, 22:0, and palmitic acid, 16:0 (approx. 11%). In the protein moiety, at least 16 amino acids were determined; these amino acids were identical in both endotoxin types, but their total content was higher in the R form, giving an R:S ratio of 1.7 +/- 0.2. The sugar moiety consists of galactose, glucosamine and either rhamnose (in S endotoxin) or aldoheptose (in R endotoxin). The difference of the chemical composition of the sugar moiety is believed to account for the diametric difference in the immunochemical character, in particular the different behaviour in the electric field, of both endotoxin types. The average content of 3-deoxy-D-manno-2-octulosonic acid was determined as 0.5% for both S and R endotoxin. Trace amounts of O-phosphorylethanolamine were found. Individual aspects of the chemical and immunochemical analysis are discussed in detail.

Amino Acids↗
PubMed1972

Purification of bacterial endotoxins by zonal centrifugation.

In this paper, we describe a cultivation procedure in large-capacity fermentors (200 liters) and the purification of the Salmonella crude extracts by means of zonal centrifugation in a sucrose gradient. Briefly, the endotoxin has been extracted from salmonellae with hypertonic solutions. The crude endotoxin was shown to contain several antigens, mainly r(1), r(2), r(3), or heterologous antigen. The heavy endotoxin was isolated and purified previously by enzymatic digestion, followed by a series of gel filtrations on Sephadex or Sepharose columns. We report the isolation and purification of heavy endotoxin in sucrose gradients, with the use of a B XIV titanium zonal rotor. From 150 to 300 mg of the crude material resuspended in a solution containing 1 m sodium chloride, 0.1 m sodium citrate, and 2.5% (w/w) sucrose, has been submitted to zonal centrifugation in gradients consisting of 5 to 25% (w/w) sucrose, also containing 1 m sodium chloride and 0.1 m sodium citrate. An overlay of 200 ml of 1 m sodium chloride-0.1 m sodium citrate was introduced after the sample. The separations were obtained after centrifugation for 3.5 hr at 35,000 rev/min (integralw(2)dt = 1.66 x 10(11)) at 4 C; the heavy endotoxin sedimented as heterogeneous material, from the middle toward the distal portions of the gradient. The heterologous antigens (r(1), r(2), r(3)), as well as bacterial proteins, remained in the sample zone. The heavy endotoxin recovered from the gradients was quite pure, as revealed by immunodiffusion tests against several antibacterial sera.

Animals↗