PubMed Health⌕ Search

Biomedical subjects

E J Macarak

Publications and source records attributed to E J Macarak.

64 records · Page 4Linked to original sources
PubMed1978

Synthesis of cold-insoluble globulin by cultured calf endothelial cells.

Radiolabeled amino acids were incorporated into nondialyzable protein by cultures of endothelial cells derived from calf aorta. Antibody prepared against purified bovine plasma cold-insoluble globulin (CIG) formed a strong precipitin line upon immunodiffusion against 3H-labeled proteins from endothelial cell culture media. This precipitin line formed a line of identity with the precipitin line formed by anti-CIG and purified CIG. Double-antibody immunoprecipitation of 3H-labeled protein showed that 36.3% of the radioactivity was specifically precipitated by the anti-CIG antibody. Gel filtration and polyacrylamide gel electrophoresis of the immunoprecipitate indicated that it contained a single protein species whose molecular weight was consistent with that of CIG isolated from plasma. When cultured cells were examined by indirect immunofluorescence microscopy, the endothelial cells stained specifically with anti-CIG antibody. These data indicate that cultured endothelial cells derived from calf aorta synthesize and secrete a protein antigenically similar to CIG.

Animals↗
PubMed1978

Comparative adherence of granulocytes to endothelial monolayers and nylon fiber.

Adherence of granulocytes to tissue culture monolayers of endothelium averaged 26.2 +/- 1.3% SEM, which was similar to their adherence on 50-mg nylon fiber columns (27.7 +/- 3.6%). In contrast, adherence to epithelial cells, fibroblasts, kidney cells, and plastic Petri dishes without monolayers was only 12.4, 9.9, 11.1, and 4.3%, respectively. Cyclic nucleotides and adherence-modifying plasma factors induced changes of adherence to endothelium similar to those in nylon fiber columns. Adherence of granulocytes in whole blood was the same as for purified granulocytes in Hank's balanced salt solution. Exposure of endothelial monolayers to 0.18% trypsin for 10 min reduced subsequent granulocyte adherence to 25.2% of control values. Incubation of trypsin-treated monolayers with nutrient medium for 4 h did not improve adherence, but values returned to normal or above by 24 h, with or without serum proteins present in the nutrient medium. The similarity of granulocyte adherence to nylon fiber and to endothelial monolayers in vitro suggests that results with the nylon fiber assay reflect in vivo granulocyte-endothelium interaction. Furthermore, the endothelial monolayer offers a new model for studying this cell-cell relationship in vitro.

Adhesiveness↗
PubMed1977

Properties of calf endothelial cells in culture.

Calf aorta endothelial cells, obtained by collagenase treatment of vessels from freshly killed animals, were cultured in medium 199 supplemented with fetal bovine serum, amino acids, and vitamins. The material released from the vessel wall after collagenase treatment consists of clumps of cells which quickly attach to the dish and spread to form confluent islands of cells. These islands of cells coalesce to form a confluent monolayer in 6 to 8 days. Cultures labeled with [3H]thymidine show an increase in labeling commencing 3 days after initial culture. Cells within monolayers do not overgrow one another and retain their epithelioid appearance after subculture. Identification of endothelial cells was based on culture morphology and by the presence of factor VIII antigen as localized by indirect immunofluorescence microscopy. These data indicate that large numbers of endothelial cells (5 to 7 x 10(6) cells per aorta) can be obtained and maintained in culture.

Animals↗
PubMed1976

Characterization of the collagen synthesized by endothelial cells in culture.

[14C]Proline and [14C]lysine were incorporated into collagen by cultures of endothelial cells derived from calf aortae. The isomer 3-hydroxy[14C]proline accounted for 10% of the total hydroxy[14C]proline in the collagen isolated from the medium. Approximately 81% of the hydroxy[14C]lysine isolated from the medium was glycosylated, and 91% of the glycosylated hydroxy[14C]lysine was in the form of the disaccharide glucosylgalactose. Gel filtration chromatography or acrylamide gel electrophoresis in the presence of sodium dodecyl sulfate indicated that the initially synthesized peptide chain of [14C]collagen had a molecular weight of about 135,000; after pepsin digestion this was converted to 115,000. The ratio of hydroxy[14C]proline to total [14C]proline x 100 in the pesin-resistant fraction was 59. When examined by immunofluorescence microscopy, the endothelial cultures stained positively with antiserum to (Type IV) collagen from basement membrane of bovine anterior lens capsule. The data indicate that cultured endothelial cells derived from calf aortae synthesize collagen that resembles that of basement membrane collagen.

Aorta↗
PubMed1975

An ultrastructural study of adhesive junctions in reaggregates of unincubated chick embryos.

Cell suspensions obtained by the dissociation of unincubated chick embryo blastoderms were allowed to reaggregate on a gyratory shaker for 24-48 hours. The reaggregates which form during this period consist of an inner phase of tightly packed cohesive cells surrounded by an external phase of loosely packed cells. This sorted out arrangement achieves its definitive form between 24 and 48 hours of rotation culture. It was determined that the external phase consists of primitive ectoderm and that the internal phase consists of primitive endoderm. Both 24- and 48-hour reaggregates were examined in the electron microscope and observations were directed to areas of close membrane apposition between cells. In 48-hour reaggregates, primitive endoderm cells were joined by many specialized junctions (desmosomes). The formation of desmosomes in reaggregates of dissociated unincubated chick embryo cells was correlated with the sorting out process.

Animals↗
PubMedDate not supplied

Strain measurements in cultured vascular smooth muscle cells subjected to mechanical deformation.

Early work in the field of biomechanics employed rigorous application of the principles of mechanics to the study of the macroscopic structural response of tissues to applied loads. Interest in the functional response of tissues to mechanical stimulation has lead researchers to study the biochemical responses of cells to mechanical loading. Characterization of the experimental system (i.e., specimen geometry and boundary conditions) is no less important on the microscopic scale of the cell than it is for macroscopic tissue testing. We outline a method for appropriate characterization of cell deformation in a cell culture model; describe a system for applying a uniform, isotropic strain field to cells in culture; and demonstrate a dependence of cell deformation on morphology and distribution of adhesion sites. Cultured vascular smooth-muscle cells were mechanically deformed by applying an isotropic strain to the compliant substrate to which they were adhered. The state of strain in the cells was determined by measurement of the displacements of fluorescent microspheres attached to the cell surface. The magnitude and orientation of principal strains were found to vary spatially and temporally and to depend on cell morphology. These results show that cell strain can be highly variable and emphasize the need to characterize both the loading conditions and the actual cellular deformation in this type of experimental model.

Animals↗