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Biomedical subjects

G Füst

Publications and source records attributed to G Füst.

At least 181 records · Page 10Linked to original sources
PubMed1980

Evaluation of different methods for detecting circulating immune complexes. An inter-laboratory study.

Forty serum samples of healthy blood donors and 60 sera of SLE patients were tested in parallel by 7 different assays for detecting immune complexes. Significantly higher titres and significant higher incidence of positive results were observed in the patient group than in the control group in 6 tests. No test discriminated between patients in an active stage of the disease and those whose disease was inactive. Significantly higher immune complex levels were found in lupus nephritis than in the non-nephritic patients by the complement consumption test. Significant positive correlation was obtained between the results of the macrophage aggregated IgG uptake inhibition and PEG-precipitation tests and between two tests based on the interaction of the complexes with the complement system. A characteristic 'profile' of the immune complex assay was observed in the course of the repeated testings of the same patients. The results indicate that the different methods detect different types of immune complexes present in the blood of the patients.

Antigen-Antibody Complex↗
PubMed1980

Serial measurement of circulating immune complexes in the sera of patients with leukaemia.

The occurrence of circulating immune complexes was studied in 220 sera of 86 patients with leukaemia. Three tests were used in parallel: the 125I-C1q-binding assay, the complement consumption test and C1q solubility test. Positive results in at least two assays were found in 64% of the patients and in 88% of the 32 serially investigated patients. An association was found between the elevated immune complex level and the blastic phase of the disease. A fluctuation of the immune complex level-independent of the clinical course of leukaemia-could also be demonstrated. The peaks of these types of fluctuations obtained by the different tests did not coincide on several occasions. These findings suggest that the composition of immune complexes changes in the course of the disease.

Antigen-Antibody Complex↗
PubMed1980

Studies on the composition and elimination of circulating immune complexes in leukaemia.

Longitudinal studies for the detection of circulating immune complexes (CIC-s) were performed in leukaemic patients using three methods in parallel. Results of these studies indicated that immune complexes in leukaemia are heterogeneous and their composition changes in the course of the disease. These results were supported by the changes in the concentration of a complement component (C1) and in the IgG subclasses in the immune complex-enriched fraction prepared by polyethylene glycol precipitation from different serum samples of individual patients with leukaemia. CIC-s from leukaemic patients are normally engulfed by granulocytes of healthy donors. The phagocytic capacity of leukaemic blast cells is hampered. The phagocytic activity through Fc and C3 receptors of peripheral mononuclear cells of leukaemic patients did not run parallel. On the basis of these studies it may be surmised that the total phagocytic capacity of the leukaemic patients cannot keep pace with the increased rate of immune complex formation.

Antigen-Antibody Complex↗
PubMed1980

Serum complement levels in patients with cancer of the uterine cervix before and after radiation therapy.

With single radial immunodiffusion method the level of the third component of the complement was investigated in 153 cervix cancer patients. In some cases the level of the fourth component of the complement and total hemolytic activity of the complement were parallely determined. The C'3 values elicited a polarized distribution pattern in contrast to the normal distribution of the controls. Mean C'3 level increased simultaneously with the progress of the disease up to Stage III, and decreased only in Stage IV. On the contrary, C'4 level was stable and practically equaled the normal value. Total hemolytic activity of the complement in cervix cancer patients usually exceed normal values. The C'3 changes during radiation therapy contradicted its role as an acute phase protein.

Adult↗
PubMed1979

The heterogeneity of Fc receptors on human peripheral mononuclear blood cells.

Fc-receptor positive peripheral blood mononuclear cells (PMBC) behaved differently after a temperature shift from 4 to 37 degrees. Two types could be distinguished. Type I FcRI+PMBC were transformed to FcR-while type II FcRII+PMBC retained their FcR as measured by EA rosettes. The supernatants of the PMBC or the shed receptor purified on a Sepharose 4B-aggregated human IgG column blocked the EAR formation of FcRI+PMBC but had no effect on EAR information of FcRII+PMBC. An investigation was made into the reason why rosette formation by Fcrii+ cells could not be inhibited by FcRI. As an explanation, the role of differences in affinity or subclass specificity was excluded while the binding site(s) on the IgG molecule for FcRI and II proved to be different. The FcRII+PMBC had a greater cellular avidity for sensitized erythrocytes than FcRI+PMBC. The different states of FcR-s in the cell membrane are discussed as a possible source of heterogeneity.

Antibody Affinity↗
PubMed1978

Studies on the occurrence of circulating immune complexes in vascular diseases.

The presence of circulating immune complexes was studied in 347 samples of serum from 212 patients with various vascular diseases. Two quantitative methods (complement-consumption assay and C1q-solubility test) were used for the measurement of the concentration of the complexes. Immune complexes were detected in each group of patients tested (coronary arteriosclerosis, myocardial infarction, cerebral artery sclerosis, arteriosclerosis obliterans, phlebothrombosis, pulmonary infarction). A high proportion of positivity was recorded in myocardial infarction (in 43 patients out of the 94 tested) and in arteriosclerosis obliterans (7 out of 11 cases). The possible pathogenic role of the circulating immune complexes is discussed.

Aged↗
PubMed1978

The effect of clofibrate and pyridinol carbamate on the circulating immune complexes and cellular immune response in experimental atherosclerosis.

Cholesterol-fed rabbits were treated with clofibrate, pyridinol carbamate and with both drugs simultaneously. The quantity of circulating immune complexes in the sera of the animals was measured weekly and the migration inhibition test was carried out in the 12th week of the experiment. The trend of the changes in the concentration of the immune complexes was rather similar to that of the cellular immune response. Compared with the values obtained in the control animals, in the cholesterol-fed group a markedly higher level of immune complexes and a significant migration inhibition could be detected. The administration of clofibrate or pyridinol carbamate alone had no effect on the concentration of immune complexes. Pyridinol carbamate did not influence the migration inhibition; however, it became similar to the healthy controls in the clofibrate-treated group. Simultaneous treatment with both drugs resulted in a decrease in the quantity of immune complexes and a diminution of the migration inhibition.

Animals↗
PubMed1978

Possible mechanisms of the first step of the classical complement activation pathway: binding and activation of C1.

Different immunoglobulin preparations of human monoclonal IgM, normal human and rat IgG, as well as purified rabbit antibodies were treated by various methods, fragmentation, aggregation and complexing with antigen. The ability of the treated and untreated preparations to fix isolated human C1, to activate the classical complement pathway (to consume C4 in normal human serum) were compared. It was found that the different methods affected the conformation of the immunoglobulin molecules in different ways and induced changes to a greater or lesser extent in the two capacities of the preparations tested. In the case of the monoclonal IgM preparation a strong C1-fixation was observed without measurable complement activation. Other preparations, interfacially aggregated human IgG, BSA-anti-BSA and OA-anti-OA immune complexes had a very weak C1-fixing but a marked complement activating capacity. Some preparations, e.g. heat-aggregated IgG, both fixed and activated C1 effectively, aggregates with a complement-activating capacity without C1-fixing effect were separated by gel-filtration. It was demonstrated further, that at a given time only a part of the activated C1 molecules could be found fixed to the immunoglobulins, the other part was released into the fluid phase after activation. On the basis of the results of this and previous studies a hypothesis is proposed suggesting three possible results of the interaction between C1 and the different preparations: (1) firm fixation and activation; (2) binding not followed by activation and (3) a transient binding leading to activation. The possible application of this hypothesis for the interpretation of the results of the different methods for detecting immune complexes is discussed.

Angioedema↗
PubMed1978

Isolation and characterization of Fc-receptors shed from human peripheral mononuclear cells.

Supernatants of human peripheral mononuclear cells containing membrane components shed in consequence of 4--37 degrees temperature shift were used as source for isolation of Fc-receptors (FcR). Aggregated IgG1 myeloma protein and TMV-anti-TMV complexes proved suitable sorbents to adsorb quantitatively and specifically the FcR-s. The isolated FcR interacts only with IgG and not with IgM. No haemagglutination was observed when the isolated FcR was incubated with sensitized human Rh+ red blood cells. Complement dependent lysis of sheep red blood cells was not inhibited by the isolated FcR-s. The interaction between IgG and SpA from Staphylococcus aureus (Cowan I) bacteria was not inhibited when red blood cells sensitized with IgG were preincubated with the isolated FcR-s. The differences between the FcR-like material isolated from supernatants of peripheral human mononuclear cells and those secreted by stimulated T cells or produced by lymphoblastoid cell lines are discussed.

Binding Sites, Antibody↗