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Biomedical subjects

T Vartio

Publications and source records attributed to T Vartio.

89 records · Page 5Linked to original sources
PubMed1981

Fibronectin remains in the cytoskeletal preparations of cultured human fibroblasts.

Cytoskeleton models were produced by treating cultured human embryonal fibroblasts with Triton X-100 and actomyosin dissociating buffers. Morphological studies indicated that in addition to nuclear residues and intermediate filaments, both plasma membrane remnants and substratum-associated, pericellular material remained on the culture substratum. By immunochemical analysis the extracellular material was identified as fibronectin. The results suggest that fibronectin is associated with the nucleus-anchoring cytoskeleton of cultured human fibroblasts.

Actins↗
PubMed1981

Transformation-enhancing activity of gelatin-binding fragments of fibronectin.

Studies have established that cryoprecipitates of the plasma of tumor patients contain a biological activity enhancing morphological cell transformation (transformation-enhancing factor; TEF) in cultures of chicken embryo fibroblasts infected with temperature-sensitive mutants of Rous sarcoma virus. We report here that similar TEF activity is effected by defined fragments of human plasma fibronectin obtained by limited digestion with major humoral or tissue proteinases. TEF activity was obtained from plasminolytic fragments of fibronectin and from cathepsin G-treated fibronectin. No activity was recorded from intact dimeric fibronectin or its reduced and alkylated subunits, from fibrinogen or its plasminolytic fragments, or from plasmin (EC 3.4.21.7) or cathepsin G (EC 3.4.21.20) treated or untreated with proteinase inhibitors. All of the TEF activity of the proteolytic fragments of fibronectin was located on the gelatin-binding peptides. The minimum effective doses in the TEF assay were 750 ng/ml of plasmin-treated fibronectin, 100 ng/ml of gelatin-binding plasminolytic fibronectin (enriched in Mr 180,000--190,000 polypeptides), and 100 ng/ml of gelatin-binding fragments of cathepsin G-treated fibronectin (enriched in a Mr 30,000 fragment). TEF activity of proteinase-treated fibronectin was inhibited by gelatin and by intact dimeric fibronectin. The potent TEF activity of proteolytic fragments of fibronectin raises the possibility that they may have a role in malignant transformation.

Animals↗
PubMed1981

Fibronectin in synovial fluid and tissue in rheumatoid arthritis.

Fibronectin is a glycoprotein found in body fluids, loose connective tissue matrix and in basement membranes. Fibronectin in rheumatoid arthritis synovial fluid was immunologically indistinguishable from the plasma form, as shown by double-diffusion analysis. Fibronectin isolated from rheumatoid synovial fluid by affinity chromatography on gelatin--Sepharose had a polypeptide pattern similar to that of plasma fibronectin in SDS--polyacrylamide gel electrophoresis. In fifty-one patients with rheumatoid arthritis and related diseases fibronectin concentrations is synovial fluid were 445 +/- 103 micrograms/ml (mean +/- SD) and within normal range, 335 +/- 52 micrograms/ml, in plasma. Immunofluorescence staining showed a prominent increase of fibronectin in the proliferating synovial connective tissue in rheumatoid arthritis as compared to normal synovial membrane. The results suggest an increased local production of fibronectin in rheumatoid synovial tissue.

Arthritis, Rheumatoid↗
PubMed1981

Cultured human amniotic fluid cells characterized with antibodies against intermediate filaments in indirect immunofluorescence microscopy.

Cells cultured from second trimester human amniotic fluid were characterized in indirect immunofluorescence (IIF) microscopy using specific antibodies against the subunit proteins of different types of cytoskeletal intermediate filaments. Most of the amniotic fluid cell cultures contained only epithelial cells as indicated by the positive keratin-fluorescence in IIF. Five distinct types of keratin-positive cells could be characterized. A dominating cell type (E-1) in most cultures were rapidly proliferating epithelial cells, previously called amniotic fluid cells (AF-cells). These cells showed a fibrillar cytoplasmic fluorescence both with keratin antibodies and with antibodies against vimentin, the fibroblast type of intermediate filament protein. E-1 cells did not show the typical cell-to-cell arrangement of keratin fibrils between the adjacent cells, a characteristic previously found in most cultured epithelial cells. Most of the cultures also contained large epitheloid cells (E-2), showing a fine fibrillar cytoplasmic organization of both keratin- and vimentin filaments, clearly different from that seen in E-1 cells. Several cultures contained two additional epithelial cells both showing the typical cell-to-cell arrangement of keratin fibrils (E-3 and E-4). These two cell types could be distinguished because of their distinct difference in size. E-4 cells typically grew as small cell islands among other epitheloid cells. Amniotic fluid cell cultures occasionally contained also large multinucleated cells (E-5), which appeared to contain large amount of fibrillar keratin. Fibroblastic cells, identified by their decoration only with antibodies against vimentin, were rarely found in amniotic fluid cell cultures. Interestingly, in such cultures some cells with a fibroblastoid appearance were identified as epithelial cells on the basis of the positive keratin-fluorescence. The results show the suitability of IIF with cytoskeletal antibodies in characterization of heterogenous cell populations and indicate that normal amniotic fluid cell cultures mostly contain epithelial cells.

Amniotic Fluid↗
PubMed1980

Polypeptides of human plasma fibronectin are similar but not identical.

Human plasma fibronectin migrated in electrophoresis after reduction of the disulfide bonds in SDS-polyacrylamide gels as two closely spaced polypeptide bands. These polypeptides, the A chain (Mr 220 000) and the B chain (215 000), were isolated from slices of slab gels. The two isolated chains were immumologically indistinguishable when tested by double immunodiffusion against antiserum to plasma fibronectin. Identical peptides were obtained from both chains after Staphylococcus aureus proteinase digesting or after cyanogen bromide cleavage, respectively. Kinetic analysis of plasmin digestion of isolated dimeric fibronectin, however, suggested that the A chain was cleaved more rapidly than the B chain and that the primary plasmin cleavage products of fibronectin, the 200 000 and 190 000 polypeptides, were derived from the A and B chain, respectively. The basis for the difference between the A and B chains of human plasma fibronectin identified here, is, at present, unknown. Proteolytic or some other posttranslational processing of a common fibronectin polypeptide seems unlikely since also the newly synthesized fibronectin, isolated from human fibroblast cultures pulse-labeled for 5 min, appeared as two closely spaced polypeptide bands in SDS-gel electrophoresis.

Electrophoresis, Polyacrylamide Gel↗
PubMed1980

Rhabdomyosarcoma of the oesophagus. Light and electron microscopic study of a rare tumor.

A 61-year-old man was operated for a large tumor, 12 x 4 cm in size, in the lower third of the oesophagus. The tumor had the appearance of a pleomorphic rhabdomyosarcoma showing cross striations by light microscopy and typical sarcomeres by electron microscopy. This is the fifth undisputed oesophageal rhabdomyosarcoma described in the literature and the first examined using electron microscope.

Esophageal Neoplasms↗
PubMed1980

Evaluation of amantadine in the prophylaxis of influenza A (H1N1) virus infection: a controlled field trial among young adults and high-risk patients.

The usefulness of amantadine in the protection of humans against influenza A (H1N1) virus was evaluated in a double-blind field trial with 555 volunteers in Finland in the winter of 1978. Three populations--patients in a general hospital, adults in a home for the aged, and two groups of military conscripts--were chosen. Epidemic influenza occurred only in the two groups of conscripts: the incidence of serologically verified influenza was 66% and 83% in the groups that received placebo and 43% and 51% in the groups that received amantadine, giving protection rates of 36% (P = 0.05) and 39% (P = 0.001). The evaluation of the effect of amantadine on the occurrence of illness was obscured by concomitant adenoviral infections that caused influenza-like symptoms. No clear difference in the occurrences of side effects was observed between the placebo and amantadine-treated groups; however, a significantly greater number of participants who took 200 mg of amantadine/day (16.9%) stopped medication during the trial as compared with the placebo groups (7.6%) (P < 0.02).

Adult↗
PubMed1980

Spontaneous and polyamine-induced formation of filamentous polymers from soluble fibronectin.

Fibronectin is a high-molecular-weight glycoprotein present in a soluble form in plasma and in other body fluids and as insoluble protein in connective tissue matrix. This study reports that soluble fibronectin is polymerized into filamentous structures and that polyamines stimulate this process and precipitate fibronectin. Fibronectin purified from human plasma under non-denaturing conditions appeared after negative staining as non-globular extended structures in the electron microscope. During storage of purified fibronectin at +4 degrees C, in particular a low ionic strength, increasing amounts of the protein appeared as protein filaments. These filaments had a diameter of 2--3 nm and a length of up to several micrometers. The filaments also formed bundles of variable thickness, apparently through lateral association. These structures could also be visualized by phase-contrast microscopy. Polyamines, at a concentration of 1--5 mM and at a low ionic strength, induced a rapid, extensive polymerization of fibronectin into filamentous structures. The effect increased in the order putrescine less than spermidine less than spermine. Polyamine-induced precipitation of fibronectin was reversible upon removal of the polyamine. Fibronectin secreted by normal and by malignant cells could be fairly selectively precipitated from the culture medium with polyamines. The observed filamentous polymers of soluble fibronectin resemble the filamentous fibronectin-containing pericellular structures in fibroblast cultures and may provide a model for studies on the deposition of fibronectin in matrix form.

Chromatography, Agarose↗
PubMed1978

Comparison of polypeptides from cultured human fibroblasts and sarcoma cells.

The proteins in cell layers of cultured normal diploid human skin (ES, ER) and lung (WI-38) fibroblasts were compared to those of SV40-transformed human fibroblasts (WI-38/VA-13), human rhabdomyosarcoma (RD) and fibrosarcoma (HT-1080) cells using metabolic amino acid and sugar labeling and surface labeling with tritiated sodium borohydride after oxidation with galactose oxidase. The labeled proteins were analysed by sodium dodecyl sulfate polyacrylamide gel electrophoresis and autoradiography (fluorography). A transformation-associated decrease in the pericellular glycoprotein fibronectin (subunit molecular weight, 220 000) and in the synthesis of a set of polypeptides in the 130 000--180 000 dalton region was seen. Synthesis of a glycosylated 160 000 dalton polypeptide was markedly reduced. In transformed cells distinct increases of several specific polypeptides was detected in both [35S]methionine and [3H] mannose incorporation experiments but not using the surface labeling method.

Animals↗
PubMedDate not supplied

Constrictive pericarditis following coronary bypass reoperation. Fibrotic pericardium and a foreign body reaction.

A 65-year-old male patient underwent two bypass operations because of coronary artery disease. After the second operation he developed congestive heart failure with breathlessness, ankle swelling, hepatomegaly and poor exercise tolerance. Echocardiographic and haemodynamic findings were characteristic of constrictive pericarditis. Pericardiectomy was performed three months after the second operation. The retrosternal space was replaced with fibrotic, patchy hyalinic tissue, and the pericardium was thick and rigid. Histologically, the thickened pericardium showed dense fibrosis and foreign-body granulomas with large multinuclear giant cells and irregular crystals. This report indicates that foreign body reaction following coronary artery bypass operation may result in constrictive pericarditis with severe heart failure.

Aged↗