PubMed Health⌕ Search

Biomedical subjects

O Saksela

Publications and source records attributed to O Saksela.

64 records · Page 4Linked to original sources
PubMed1981

Basal lamina components in experimentally induced skin blisters.

The distribution of basement membrane glycoproteins, fibronectin, laminin, and type IV collagen was studied in experimentally induced skin blisters in which the epidermis is separated from the dermis through the lamina lucida part of basal lamina. Fibronectin was found surrounding the blister cavity and in a primary covering formed on the bottom of the blister. Neither laminin nor type IV collagen were incorporated into this clot-like matrix. The layer of laminin found in normal epidermal-dermal junction was found to be cleaved by the blistering method, whereas all type IV collagen antigenicity was confined to the base of the blister presumably due to its location in the lamina densa part of the basal lamina. No interstitial collagens were found in the separated epidermis in accordance with previous ultrastructural evidence. These studies support the proposed role of laminin in the adhesion of epidermal cells to basement membrane collagen.

Basement Membrane↗
PubMed1981

Inflammatory cells, IgA, C3, fibrin and fibronectin in skin lesions in dermatitis herpetiformis.

Skin lesions were produced by application of 50% potassium iodide to twelve patients with dermatitis herpetiformis (DH). Perivascular cellular infiltrates were found to be characteristic of developing lesions. The cells were mainly round cells; alpha-naphthyl acetate esterase staining revealed that in 24-h lesions the mean percentage of T-lymphocytes was 43%, that of mononuclear phagocytes 6% and that of non-T/non-M cells (mainly B-lymphocytes) 44%. The percentage of the latter was highest (mean 81%) in 6-h specimens, suggesting that these cells are participating in the early stages of lesion formation. The infiltrating cells in dermal papillae and within subepidermal vesicles were predominantly polymorphonuclear leukocytes (mean 86%) with some mononuclear phagocytes and non-T/non-M cells. Immunofluorescence examination confirmed that fibrin deposition is characteristic of the initial lesions of DH and showed that the same is true of fibronectin. Seven out of eight patients had fibronectin deposits in dermal papillae. IgA was found in all and C3 in most of the specimens and, with the exception of papillary vesicles and blister cavities, the intensity of IgA and C3 fluorescence showed no marked alterations during the development of lesions.

Complement C3↗
PubMed1981

Cultured human syncytiotrophoblasts synthesize pregnancy-specific beta-1-glycoprotein (SP1).

The synthesis of pregnancy-specific beta-1-glycoprotein (SP1) was studied in human syncytiotrophoblast cultures from first trimester placentas. Incorporation of 35S-methionine into SP1 was demonstrated by immunoprecipitation and polyacrylamide gel electrophoresis. In double diffusion the precipitation line of neosynthesized SP1 gave a reaction of complete immunological identity with maternal serum SP1. By indirect immunofluorescence intracellular SP1 was localised in the perinuclear region of the cells. The average rate of SP1 release into culture fluid was 600 ng/mg protein in 24 hours. On a molar basis the release of SP1 was 10 times less than that of human chorionic gonadotrophin (hCG). Our results demonstrate, for the first time, that cultured human syncytiotrophoblasts synthesis SP1 immunologically indistinguishable from placental SP1.

Cells, Cultured↗
PubMed1981

Presence of alpha 2-macroglobulin in normal but not in malignant human syncytiotrophoblasts.

alpha 2-Macroglobulin (alpha 2M) was demonstrated in normal syncytiotrophoblasts of both early and full-term human placentas using immunocytological staining. alpha 2M was also detected in hydatidiform moles, the benign tumors of proliferating syncytiotrophoblasts. In contrast, no alpha 2M was detected in invasive moles or choriocarcinomas. In culture conditions, both normal syncytiotrophoblasts and choriocarcinoma cells, identified by production of human chorionic gonadotropin, were negative when stained for alpha 2M or when studied using metabolic labeling and immunoprecipitation or radioimmunoassay. However, alpha 2M was taken up from added human serum by the cultured syncytiotrophoblasts, whereas choriocarcinoma cells remained negative also under these conditions. The possible role of alpha 2M in the regulation of proteolysis in cell invasion is considered.

Blood↗
PubMed1977

Distribution of a major surface-associated glycoprotein, fibronectin, in cultures of adherent cells.

Fibronectin was present in media and cell layers of cultures of adherent cells from human skin, kidney, lung, chest wall, liver, and heart. Cell-surface fibronectin, visualized by immunofluorescence, was in dense fibrillar (cultures from lung), discrete fibrillar (e.g., cultures from skin), or punctate (some cultures from kidney) structures. The subunit sizes of cell-surface fibronectin and fibronectin soluble in medium appeared identical in sodium dodecyl sulfate-polyacrylamide gels. To explain the polymorphism of cell-surface fibronectin, there must be chemical differences among the fibronectins synthesized by different cell strains or factors in the cell layer which influence fibronectin binding and aggregation.

Animals↗
PubMed1977

Synthesis and secretion of alpha-2-macroglobulin by cultured adherent lung cells. Comparison with cell strains derived from other tissues.

We studied the synthesis and secretion of alpha-2-macroglobulin by cultures of human adherent cells. Much more alpha-2-macroglobulin (measured by radioimmunoassay) accumulated in media of established strains of adherent cells derived from embryonic lung than in media of established strains derived from adult skin or rheumatoid synovium. Alpha-2-macroglobulin accumulated in media of primary cultures of adherent cells from a variety of embryonic tissues. However, the amount of alpha-2-macroglobulin accumulating in media of subsequent passage of these cells declined for all strains except those derived from lung. Immunodiffusion and double-antibody immunoprecipitation studies of cell extracts and media after incubation of cells with l-[(35)S]methionine supported the radioimmunoassay finding that adherent cells from lung synthesized and secreted more alpha-2-macroglobulin than adherent cells from skin. Intracellular alpha-2-macroglobulin could not be detected by radio-immunoassay or visualized by immunofluorescent microscopy, suggesting that synthesized alpha-2-macroglobulin is rapidly secreted. Plasminogen-rich fibrin clots were lysed in culture media of adherent cells from embryonic lung and, to a lesser extent, heart. Adherent cells from other tissues, which produced less alpha-2-macroglobulin, did not lyse fibrin clots. However, all cultures of adherent cells contained pericellular fibronectin, a large, external, transformation-sensitive glycoprotein known to be cleaved by plasmin. We speculate that production of alpha-2-macroglobulin may be a means for protease-secreting normal cells to preserve cell surface integrity and that alpha-2-macroglobulin synthesized locally in lung may protect lung tissues from a variety of proteases.

Cell Adhesion↗
PubMed1976

Fibroblast surface antigen (SF): molecular properties, distribution in vitro and in vivo, and altered expression in transformed cells.

We have recently described a cell type-specific surface (SF) antigen that is deleted in chick fibroblasts transformed by Rous sarcoma virus, SF antigen is a major surface component and makes up about 0.5% of the total protein on normal cultured fibroblasts. The antigen is shed from normal cells and is present in circulation (serum, plasma), and in vivo, also, in tissue boundary membranes. The molecular equivalents of both cellular and serum SF antigen are distinct, large polypeptides, one of which (SF210, MW 210,000) is glycosylated and, on the cell surface, highly susceptible to proteases and accessible to surface iodination. Immunofluorescence and scanning electron microscopy have indicated that the antigen is located in fibrillar structures of the cell surface, membrane ridges, and processes. Human SF antigen is present in human fibroblasts and in human serum. We have recently shown that human SF antigen is identical to what has been known as the "cold-insoluble globulin" and that it shows affinity toward fibrin and fibrinogen. Our results also indicate that loss of the transformation-sensitive surface proteins is due not to loss of synthesis but to lack of insertion of the protein in the neoplastic cell surface. Both normal and transformed cells produce the SF antigen, but the latter do not retain it in the cell surface. The loss of SF antigen, a major cell surface component, from malignant cells creates an impressive difference between the surface properties of normal and malignant cells. The possible significance of SF antigen to the integrity of the normal membrane and its interaction to surrounding structures is discussed.

Animals↗