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Biomedical subjects

D Barac

Publications and source records attributed to D Barac.

10 recordsLinked to original sources
PubMed1985

Hemagglutination assay for human serum fibronectin.

A hemagglutination assay for human serum fibronectin (Fn) is described. The assay is based on the capacity of Fn to bind to gelatin. Purified and human serum Fn agglutinate chromic chloride treated sheep red cells coated with gelatin in a quantitative and reproducible manner. The lowest Fn concentration giving positive hemagglutination was found to be 7 micrograms/ml, a sensitivity making it suitable for measurement of Fn in both normal and pathologic sera. The assay is simple and rapid and does not require specialized equipment.

Animals↗
PubMed1983

C1q has albumin binding activity but does not interfere in the hemagglutination test for anti-albumin antibodies.

Two factors in the sera of patients with liver disease interact with polymerized human serum albumin (HSAP). These are anti-albumin antibodies (AAA) and receptors for polymerized albumin on HBsAg. Recently it was demonstrated by radioimmunoassay that purified human C1q also binds HSAP. Our data confirm the reaction between purified human C1q and HSAP by passive hemagglutination and by indirect immunofluorescence of HSAP-coated erythrocytes (E-HSAP). It is shown that although purified C1q binds HSAP, in the serum, the AAA and not C1q are responsible for the albumin binding activity in HBsAg-negative sera of patients with liver disease and of normal individuals, as detected by passive hemagglutination of E-HSAP, AAA were found to inhibit the binding of serum C1q to polymerized albumin, and hence the E-HSAP hemagglutination test for AAA titration in human sera proved valid.

Antibodies↗
PubMedDate not supplied

Fibronectin and lymphocyte blast transformation.

Purified human plasma fibronectin (Fn) added to human peripheral blood leukocytes culture, from 22 healthy blood donors, phytohemagglutinin (PHA) stimulated, enhanced mitogen action in blast transformation. Daily measurement (between 1-6 days) of Fn concentration in culture supernatants incubated with PHA, Fn and associated doses of Fn and PHA, pointed out a significantly increased Fn concentration, on the fourth day, in the cultures incubated with Fn and PHA. On the fourth day of PHA stimulated cultures were found, the increased Fn concentration, as well as the maximum blast transformation. Our data suggest that Fn, synthetized by activated macrophage in intercellular cooperation processes is released in culture supernatants with a maximum on the fourth day. These results show the possible role of Fn to influence blast transformation enhancement of mitogen action.

Cells, Cultured↗
PubMedDate not supplied

Fibronectin and phagocytosis in acute and chronic infections.

Serum fibronectin (Fn) level and phagocytosis function were investigated during acute and chronic infections. Serum Fn concentration was significantly decreased in septic patients (mean +/- ES, 80 +/- 12 micrograms/ml, p less than 0.001) and was increased in chronic bronchitis patients (575 +/- 18 micrograms/ml, p less than 0.001) as compared to the controls. The phagocytosis index was decreased in septicaemia and not significantly changed in chronic bronchitis. Phagocytosis dysfunction was associated to a low serum Fn level in acute infections. Phagocytosis was stimulated in vitro, by purified Fn. Serum Fn concentration reflects the reticuloendothelial function and could be a marker of infection together with other parameters.

Acute Disease↗
PubMedDate not supplied

Plasma fibronectin level in patients with connective tissue diseases.

The level of plasma fibronectin (Fn) was studied in 40 patients with connective tissue diseases. Fn concentration was found increased in patients with rheumatoid arthritis (mean +/- SE, 560 +/- 30 micrograms/ml, p less than 0.01) decreased in patients with mixed connective tissue disease (337 +/- 12 micrograms/ml, p less than 0.05) and was not significantly different from controls in systemic lupus erythematosus, scleroderma, polymyositis. The value of plasma Fn level was found increased in active diseases and decreased in the cases, with presence of cryoprecipitates. The factors which might influence the level of plasma Fn and the possibility of using the changes of Fn concentration in the estimation of the evolution of connective tissue diseases are discussed.

Blood Sedimentation↗
PubMedDate not supplied

Serial analysis of fibronectin concentration in sera from septic patients.

Serum fibronectin (Fn) level was serially determined in nineteen septic patients. Fn concentration was found significantly decreased in septic patients (mean +/- SE, 120 +/- 11 micrograms/ml) as compared to the control (205 +/- 11 micrograms/ml). The decrease of Fn was correlated with the severity of sepsis; it was persistent and more important in severe septic cases. The lowest Fn concentration was found in nonsurviving patients (78 +/- 18 micrograms/ml). Serum Fn level may reflect the degree of organ failure and predict the evolution of sepsis.

Adult↗