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Biomedical subjects

M T Aguado

Publications and source records attributed to M T Aguado.

28 records · Page 2Linked to original sources
PubMed1984

Frequency and clinical and transfusional significance of rheumatoid factor in patients with haemophilia and von Willebrand's disease.

Using a solid-phase radioimmunoassay for IgM rheumatoid factor, increased levels were found in 24% or 82 patients with haemophilia A, in 4 of 11 patients with haemophilia B, in 2 of 11 patients with haemophilia A with inhibitors and in 4 of 12 with von Willebrand's disease. The levels of rheumatoid factor increased significantly (p less than 0.02) after factor VIII concentrate or cryoprecipitate transfusions. No clinical or transfusional side effects could be attributed in these patients in relation to the presence of rheumatoid factor.

Blood Coagulation Tests↗
PubMed1983

Capacity to solubilize immune complexes in sera and synovial fluids from patients with rheumatoid arthritis.

Fifty-six sera and 33 synovial fluids from rheumatoid arthritis patients were studied to evaluate their capacity to solubilize immune complexes. A decreased function was found in 65% of rheumatoid synovial fluids when compared with 13 osteoarthritis synovial fluids. The decrease of immune complex solubilization capacity correlated with the decrease of hemolytic activity of the alternative complement pathway (P less than 0.001) and inversely with the level of immune complexes (P less than 0.05). Synovial fluids with low and normal immune complex solubilization capacity were compared; the results confirmed a possible role of the synovial complement system in modulating the size and thus the diffusion and clearance of locally generated immune complexes.

Adult↗
PubMed1982

Ferritin levels and circulating immune complexes in patients with solid tumors.

The level of ferritin and circulating immune complexes (IC) were measured in 53 patients with solid tumors and metastasis using C1q binding assay and the conglutinin binding assay. The level of circulating IC was increased in patients (p less than 0.001) as compared to the controls. Ferritin level was increased in both male and female patients (p less than 0.001), even when the ferritin value was corrected by the aspartic transaminase value, to take for hepatic damage in account. Ferritin was not found to be an important component of immune complexes as IC ferritin did not exceed 2 per cent of total serum ferritin in the 10 patients that were investigated. These results suggest that ferritin levels and circulating IC were increased in patients with solid tumors and metastasis, but that these two parameters are not correlated.

Aged↗
PubMed1981

Decreased capacity to solubilize immune complexes in sera from patients with systemic lupus erythematosus.

The capacity to solubilize immune complexes formed in vitro is significantly decreased in patients with systemic lupus erythematosus (SLE). This complement function correlates significantly with serum C3 levels and inversely with the presence of circulating immune complexes. Clinically, patients with a decreased capacity, to solubilize complexes show a worse evolution and an increased incidence of renal involvement. In conclusion, the impaired solubilization capacity, related to low complement activity, which is observed in patients with SLE may favor the persistence of immune complexes in tissues.

Antigen-Antibody Complex↗
PubMed1980

Separation of granulocytes from peripheral blood in a single step using discontinuous density gradients of Ficoll-Urografin. A comparative study with separation by dextran.

A single-step method for separating granulocytes from peripheral blood using two different gradients of Ficoll-Urografin (F-U) density 1.075 and 1.097 g/ml) is described. The morphological, cytochemical and ultrastructural properties of neutrophils isolated by this method were compared to those isolated by dextran-enhanced sedimentation and neutrophils from the peripheral blood. These studies indicated fewer alterations in neutrophils separated by F-U centrifugation than in neutrophils concentrated by dextran. Finally, the granulocyte layer recovered by F-U fractionation was 98% pure (dextran 71%) and yielded 64% (dextran 79%) of total granulocytes.

Adult↗
PubMed1980

Evaluation of alternative pathway and factor B haemolytic activities in patients with systemic lupus erythematosus: correlations with the alternative pathway regulatory proteins.

The haemolytic activities of the complement alternative pathway and factor B were studied using a 51Cr-release assay in 77 sera from patients with systemic lupus erythematosus (SLE). These values were compared to those of several complement components and of the regulatory proteins beta H and C3b INA. There was a significant decrease in the alternative pathway activity, which correlated with a decrease in the haemolytic activity of factor B and with the activity of the classical pathway. There was a significant decrease in the level of one regulatory protein beta 1H, while the level of the other regulatory protein, C3b INA, was increased; however, there was a positive correlation between these two parameters. The results obtained suggest that the decreased activity of the alternative pathway observed in SLE reflects a consumption due to a triggering of the C3b amplification loop through the activation of the classical pathway. In one patient, an acquired deficiency of the capacity to activate the alternative pathway in the presence of inulin was observed.

Adult↗
PubMed1980

Demonstration of a local exhaustion of complement components and of an enzymatic degradation of immunoglobulins in pleural empyema: a possible factor favouring the persistence of local bacterial infections.

Local bacterial infections such as abscesses or purulent exudates most often contain numerous, easily culturable bacteria despite an intense inflammatory reaction characterized by the ingress of polymorphonuclear leucocytes. In order to understand the mechanisms leading to such a persistent infection, we used pleural empyema as a model and measured the levels and catabolism of complement as well as of immunoglobulins in 28 infectious pleural effusions associated with either a positive or with a negative bacterial culture. Classic and alternative pathway haemolytic activities, factor B and C4 haemolytic activities as well as native C3 were markedly decreased or undetectable in most culture-positive effusions when compared to culture-negative effusions (P less than 0.005); breakdown products of factor B and C3 were markedly increased in culture-positive fluids. Eleven out of 14 culture-positive fluids exhibited IgG breakdown as opposed to none of the culture-negative fluids. In seven out of 14 culture-positive fluids, incubation with 125I-IgG led to their in vitro breakdown. This proteolytic activity could be abolished by preincubation of the culture-positive fluids with normal sera. Thus, increased catabolism of complement and breakdown of immunoglobulins, both leading to local consumption of immune reactants, could be one of the causes for bacterial persistence in pleural empyema.

Complement C3↗
PubMedDate not supplied

Effect of circulating immune complexes on transfusional therapy in patients with hemophilia or von Willebrand's disease.

Circulating immune complexes were examined in patients with hemophilia or von Willebrand's disease in order to determine the immediate or long-term side effects after transfusion. The conglutinin binding assay which allows quantitation of C3bi-bearing immune complexes was used for 82 patients with hemophilia A. Immune complexes were detected in 37 (45%) of these cases prior to transfusion. Immune complexes also were detected in four of 11 patients with hemophilia A and factor VIII inhibitors, in five of 11 patients with hemophilia B, and in three of 10 patients with von Willebrand's disease. The levels of circulating immune complexes in 21 patients with hemophilia A and seven with von Willebrand's disease significantly increased 24 hours after concentrate or cryoprecipitate transfusions. Purified immune complexes from three patients with hemophilia A were shown to contain IgG, IgM, and complement components. No factor VIII coagulant or antigenic protein or fibrinogen was identified in the immune complexes using specific antisera. Side effects immediately after transfusion were not associated with immune complexes. The levels of factor VIII or IX after transfusion were not particularly decreased in relation to the presence of immune complexes. Finally, the presence of circulating immune complexes in the patients studied did not correlate with the number of transfusions, the units of concentrates injected, the presence of HBsAg or HbsAb, the levels of plasma aspartate transferase, or the presence of rheumatoid factor. Proteinuria was absent in all the patients studied.

Antigen-Antibody Complex↗
PubMedDate not supplied

[Activation of the alternative complement pathway in pleural fluid of patients with pneumonia].

It has been reported that the opsonic activity of pleural fluid is decreased in patients with pneumonia complicated by infected effusions (empyema) compared to those with sterile (metapneumonic) effusions. In this paper some parameters of complement activity in 12 patients with empyema and in 13 patients with metapneumonic effusions were compared. The hemolytic activity of the alternative pathway and of Factor B in empyemas (15 +/- 10% and 25+15%, respectively) was less than that measured in metapneumonic effusions (55 +/- 38% and 71 +/- 21%; p less than 0.01). Both parameters showed a significant correlation (r=0.76; p less than 0.01). The Ba fragment, a catabolic product of Factor B, was increased in empyema (125 +/- 59%) compared to that in metapneumonic effusions (49 +/- 24%; p less than 0.01). The levels of C3, protein of both, alternative and classical pathways, were decreased in empyema (17 +/- 29%) when compared with the levels in metapneumonic pleural effusion (42 +/- 20%; p less than 0.01). The levels of this protein were correlated with the activity of alternative complement pathway (r=0.68; p less than 0.01), as well as with those of Factor B (r=0.75; p less than 0.01). Finally, the hemolytic activity of C4, as a representative element of the classical pathway, has also shown to be decreased in empyema (6 +/- 6%) compared to metapneumonic fluids (27 +/- 28%; p less than 0.01). Significant correlations between the hemolytic activity of C4 and levels of C3 (r=0.75; p less than 0.01), the hemolytic activity of the alternative pathway (r=0.63; p less than 0.01) and the levels of Factor B (r=0.73; p less than 0.01) were demonstrated. This last suggest a simultaneous activation of both, classical and alternative pathways of complement. The complement decrease and particularly, the activation of the alternative pathway in patients with empyema could be a determinant factor of the deficient bacterial opsonization. This can explain the survival of bacteria in an empyema despite the large number of neutrophils present.

Complement Activation↗