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Biomedical subjects

R Seljelid

Publications and source records attributed to R Seljelid.

At least 109 records · Page 6Linked to original sources
PubMed1980

Separation of human monocytes on density gradients of Percoll.

Monocytes from human blood have been isolated by centrifugation in Percoll. A one-step procedure has been designed to isolate the cells from 7 ml of blood. when 5% of the white blood cells are assumed to be monocytes, an estimated average yield of 100% and a purity of 20% is achieved. The contaminating cells are almost exclusively lymphocytes. By a two-step procedure the monocytes can be obtained 90% pure with an approximate yield of 35%. The cells can be used for tissue culture without washing and they display the usual properties of mononuclear phagocytes in vitro.

Blood Coagulation↗
PubMed1980

The cellular reaction in normal and tumour-bearing mice following intraperitoneal glucan injection.

The effect of a single intraperitoneal injection of yeast glucain in C3D2 mice was studied. The optimal dose for the induction of a cellular exudate was 0.4 mg/kg, producing 17.6 x 10(6) cells on day 7 after injection. The number of T-cells, B-cells and macrophages in this exudate was analysed by the use of morphology, immunofluorescence and the non-specific esterase staining. An increase in both T-cells, B-cells and macrophages was found after glucain injection. There was an 8-fold increase in macrophages, but the increase lasted only 14 days. The increase in T-cells was smaller, but lasted at least 35 days. The effect of pretreatment with glucan on the development of an inoculated syngeneic methyl cholanthrene induced sarcoma was studied. No effect on tumour take could be demonstrated, but differences in T-cell, B-cell and macrophage content of the developing tumour were found. A strinking feature was a prolonged increase in tumour T-cell content.

Animals↗
PubMed1980

T- and B-cell-independent activation of syngeneic macrophages by murine sarcoma cells.

Mouse peritoneal macrophages were achieved by cocultivation with syngeneic sarcoma cells. The tumor cells died progressively during the cocultivation, leaving highly activated marcophages. Because of great changes in macrophage morphology during the activation, special efforts were made to identify the activated cells as macrophages by their ability to phagocytose latex and to bind opsonized sheep red cells to C3 and Fc receptors and by indirect immunofluorescence with an antimacrophage antiserum. Activation was evaluated by morphology and incorporation of [14C]glucosamine. The activation was found to be independent of the presence of T-cells, B-cells, and immunoglobulin bound to tumor cell surfaces. This was shown by removal of T-cells from the system by treatment with anti-theta and complement and by use of nude mice as the macrophage source and for tumor maintenance. Similarly, B-cells were removed by treatment with anti-immunoglobulin and complement as well as adherence to anti-immunoglobulin-coated plastic dishes. Immunoglobulin bound to tumor cells was removed by trypsinization and by elution at low pH. Culture supernatants from tumor cells and cell-free tumor ascites fluid also induced some activation of the macrophages. This activation differed from the coculture activation in both the extent and kinetics of morphological changes and gave only a small increase in [14C]glucosamine incorporation.

Animals↗
PubMed1979

Uptake and degradation of mast-cell granules by mouse peritoneal macrophages.

35S-labelled mast-cell granules isolated from mouse mastocytomas were added to mouse macrophages in vitro. The granules were avidly phagocytosed, and subsequently the radioactivity was released to the medium as inorganic [35S]sulphate. After pulse-labelling, a total of about 80% of the cell-associated radioactivity was thus released in the course of 24 h, indicating an extensive breakdown of the sulphated polysaccharides, mainly heparin, present in the granules. The uptake of the mast-cell granules caused pronounced, but reversible, spreading of the macrophages.

Animals↗
PubMed1978

Difference in the effect of immobilized ligands on the Fc and C3 receptors of mouse peritoneal macrophages in vitro.

The function of the Fc and C3 receptors on the free surface of normal and endotoxin activated mouse peritoneal macrophages seeded on glass bound antibody--antigen (AbAg) complexes or complement was examined. We found that the glass bound AbAg complexes interfered with attachment and internalization of particles recognized by the Fc receptor. The C3 receptor function in these cells was not affected. On the other hand, normal and activated macrophages seeded on glass bound complement showed no change in the function of the C3 and the Fc receptors.

Animals↗
PubMed1975

[Morphology].

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Anatomy↗
PubMed1975

Mass isolation and culture of rat kupffer cells.

Collagenase perfusion of the liver followed by pronase treatment of the cell suspension thus obtained gave a quantitative recovery of viable nonparenchymal liver cells (NPC). From these NPC, Kupffer (K) cells can be purified by attachment to tissue culture dishes. Tail vein injection of carbon 1-2 h before liver perfusion permitted stepwise calculation as well as visualization of carbon-containing K cells. When these K cells have been put into tissue culture medium with serum and incubated overnight, they exhibit typical macrophage characteristics. Phase-contrast and transmission electron microscopy showed typical macrophage morphology and scanning electron microscopy revealed well-spread cells with cytoplasmic projections and ruffled membranes. Endocytosis studies using radioactive colloidal gold and inert latex particles also indicated that these cells are highly active in pinocytosis and phagocytosis. Further characterization of K cells is the identification of Fc receptor on their membranes. Studies on lysosomal enzymes showed that purified K cells possess higher specific activities in beta-glucuronidase, acid DNase, and cathepsin D than in purified parenchymal cells.

Animals↗
PubMed1974

Evidence for a cytolytic factor released by macrophages.

Mouse peritoneal macrophages cultivated in vitro acquire a strong extracellular cytotoxic activity towards isotope labeled syngeneic erythrocytes as demonstrated by isotope release to the medium. This lytic process is mediated by an extremely labile macrophage cytolytic factor (MCF) which is not detected under ordinary tissue culture conditions with serum present in the medium. By the use of serum-free medium containing low doses of 2-mercaptoethanol MCF is stabilized and found to be an easily dialysable, low molecular substance which resists heating at 60 degrees C for 30 min.

Animals↗
PubMed1973

The cytotoxic effect of mouse macrophages on syngeneic and allogeneic erythrocytes.

A cytotoxic effect of mouse peritoneal macrophages against syngeneic and allogeneic erythrocytes was demonstrated by isotope release and release of hemoglobin. The cytotoxic effect was dependent on the contact between viable, activated macrophages and target cells. Activation was accomplished by prolonged cultivation of macrophages and by the presence of Zn(++) and Con-A. Immunization did not prove necessary. Morphological observations as well as experiments with various salt concentrations indicate that the cytotoxic reaction may involve some kind of osmotic effect upon the target cells.

Animals↗