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Biomedical subjects

T Vartio

Publications and source records attributed to T Vartio.

At least 73 records · Page 4Linked to original sources
PubMed1982

Monoclonal antibodies in analysis of cathepsin G-digested proteolytic fragments of human plasma fibronectin.

Proteolytic fragments of fibronectin, obtained by digestion with cathepsin G, were transferred electrophoretically from sodium dodecyl sulphate (NaDodSO4) polyacrylamide gels to nitrocellulose sheets and used as antigens for monoclonal antibodies. All 9 monoclonal antibodies tested reacted with undenatured intact fibronectin or its fragments applied directly to nitrocellulose sheets. Two of the clones did not react with the NaDodSO4-treated transferred material suggesting reactivity with conformational determinants. Distinct fragments of fibronectin could be detected by several of the antibodies. None of the monoclonal or the polyclonal antibodies used reacted with the Mr = 40,000 or Mr = 30,000 gelatin-binding fragments of fibronectin. However, one of the monoclonal antibodies reacted specifically with their precursor Mr = 64,000 fragment, but apparently with its gelatin-nonbinding segment. The apparent non-immunogenicity of the gelatin-binding domain is conspicuous, suggesting that it may be highly conserved in evolution. The present method, combination of controlled proteolytic cleavage with electrophoretic transfer, provides an effective means for characterization of monoclonal antibodies raised against proteins.

Animals↗
PubMed1982

Structure of the pericellular matrix: association of heparan and chondroitin sulfates with fibronectin-procollagen fibers.

Immunofluorescent staining of a pericellular matrix produced by cultured human embryonic skin fibroblasts showed a codistribution among fibronectin, heparan sulfate proteoglycans and part of the chondroitin sulfate in a fibrillar network. Isolated matrix in an "intact" form could be scraped off the dish after detergent solubilization of the cells. On centrifugation in cesium chloride density gradients, most sulfated glycosaminoglycans and matrix proteins remained associated and were recovered at a density of 1.34 g/cm3 (greater or equal to 2 M CsCl). However, when 4 M guanidine hydrochloride was included in the gradient medium, the components dissociated, suggesting that the sulfated glycosaminoglycans are bound to matrix proteins by strong noncovalent linkages. Interactions between sulfated glycosaminoglycans produced by the fibroblasts and fibronectin could also be demonstrated by affinity chromatography on immobilized plasma fibronectin and by immunoprecipitation of fibronectin in conditioned culture medium, which resulted in a coprecipitation of the sulfated glycosaminoglycans. In these two systems, the fibronectin glycosaminoglycan bonds were broken at 0.2 M salt and were apparently weaker than the bonds responsible for the structural integrity of the matrix. These findings implicate heparan and chondroitin sulfate proteoglycans as integral compounds of the pericellular matrix fibers and suggest that the association of the proteoglycans with the fibronectin-procollagen matrix is stabilized by multiple molecular interactions.

Cells, Cultured↗
PubMed1982

Expression and distribution of vimentin and keratin filaments in heterokaryons of human fibroblasts and amnion epithelial cells.

The expression of intermediate filaments of the keratin- and the vimentin-type was studied in heterokaryons of human fibroblasts and amnion epithelial cells by immunofluorescence microscopy. Fibroblasts and their homokaryons showed a fibrillar, vimentin-specific fluorescence throughout the cytoplasm but were negative when stained for keratin. Amnion epithelial cells and their homokaryons, on the other hand, showed a keratin-specific fibrillar staining, and only some of them contained also detectable vimentin. When suspended epithelial cells were fused with adherent fibroblasts, keratin fibrils spread within 3 h into the fibroblasts, intermixing with the vimentin fibrils. 1-3 d after fusion, both vimentin and keratin filaments were expressed as typical fibrillar cytoplasmic arrays, and the distribution of keratin in heterokaryons resembled closely that of vimentin. A typical cell-to-cell arrangement of keratin fibrils, seen in cultures of amnion epithelial cells, could also be found between heterokaryons. Treatment of the cultures with vinblastine sulphate induced coiling of the vimentin filaments in both homo- and heterokaryons, whereas the keratin organization was only slightly affected. Our results show that both vimentin and keratin filaments are incorporated into the cytoskeleton of heterokaryons formed between fibroblasts and epithelial cells, and that they behave in the same way as in their parental cells. Both epithelial and fibroblastic characteristics thus appear to the coexpressed in such heterokaryons.

Cell Fusion↗
PubMed1982

Histochemical and biochemical study of hereditary fibrous hyperplasia of the gingiva.

Four patients with hereditary hyperplasia of the gingiva were studied. Biopsy samples of gingival tissue contained subepithelial loose connective tissue with thick rounded fibroblasts or dense collagen-rich connective tissue with thin fibroblasts, which appeared to be inactive. These two types of fibroblasts differed in electron microscopy. Alcian blue-staining of intercellular material in various MgCl2 concentrations was similar in hyperplastic and control samples. Collagen from the hyperplastic gingiva appeared to be more mature than normal, based on the presence of stable, nonreducible cross lines. An investigation of growth hormone secretion and a treatment trial suggested that the growth retardation observed in earlier studies was due to normal variation in growth rates or (in one patient) to hypopituitarism associated with birth in breech presentation.

Adolescent↗
PubMed1982

Fibronectin in exudative pleural effusions.

Fibronectin is a glycoprotein found in body fluids, loose connective tissue matrix and in basement membranes. Fibronectin in pleural effusion was found to be immunologically indistinguishable from the plasma form, as shown by double-diffusion analysis. Fibronectin isolated from pleural fluid by affinity chromatography on gelatin-Sepharose had a polypeptide pattern similar to that of plasma fibronectin in SDS-polyacrylamide gel electrophoresis. In 28 patients with infectious or non-specific pleural effusion fibronectin concentrations in pleural fluid were 335 +/- 104 micrograms/ml (mean +/- SD), in 15 patients with malignant disease the concentrations were 369 +/- 173 micrograms/ml and in 26 patients with tuberculosis 441 +/- 103 micrograms/ml. The highest concentrations, 605 +/- 252 micrograms/ml, of fibronectin in pleural fluid were detected in 14 patients with connective tissue diseases. The results suggest that increased fibronectin concentrations reflect the presence of a pleurisy due to connective tissue disease or tuberculosis rather than other infectious or malignant disease.

Bacterial Infections↗
PubMed1982

Cytoskeleton and pericellular matrix organization of pure adult human keratinocytes cultured from suction-blister roof epidermis.

Pure adult human keratinocyte cultures were raised from suction-blister roof epidermis and cultured in MCDB-151 medium. In primary culture the epidermal cells rapidly adhered, spread and began to proliferate on collagen-coated growth substrata but not on uncoated plastic or glass substrata. A fibrillar keratin-specific fluorescence, showing a typical cell-cell arrangement, was seen in all cells in indirect immunofluorescence microscopy, whereas only some cells also showed vimentin-specific staining. A fine fibrillar fibronectin-specific surface staining was seen at the margin of attaching cells and in marginal cells of spreading cell islands, whereas no fluorescence could be seen in epidermal cells, with antibodies against type IV collagen or laminin. Interestingly, the marginal cells also showed intracellular fibronectin. The synthesis of fibronectin in epidermal cell cultures could also be revealed by metabolic labelling experiments with [35S]methionine. In contrast to primary cultures, subcultivated keratinocytes also adhered to uncoated plastic and glass substrata. After subcultivation, keratin and surface fibronectin distribution remained unaltered but after some subcultivations, most of the cells also showed fibrillar vimentin and expressed fibronectin intracellularly. The results show that the suction-blister method provides an easy way to obtain pure epidermal cell cultures without contaminating mesenchymal cells. Our results also suggest a direct role for fibronectin but not for collagen type IV or laminin in adhesion and spreading of epidermal cells in vitro.

Adolescent↗
PubMed1982

Reorganization of cytoskeletal and contractile elements during transition of human monocytes into adherent macrophages.

Indirect immunofluorescence microscopy was used to study the reorganization of contractile and cytoskeletal elements of human monocytes during their in vitro transition into macrophage-like cells. In freshly isolated monocytes, actin, myosin, alpha-actinin, and vinculin all had a diffuse distribution, whereas microtubules and vimentin-type intermediate filaments showed a distinct fibrillar organization. In culture, the cells differentiated within 1 week to two distinct cell types: bipolar fibroblastoid cells and flattened epithelioid cells. A conspicuous redistribution of actin, alpha-actinin, and vinculin from a diffuse cytoplasmic location into distinct punctate foci at the substratum-facing side of the cells was seen already at the early attachment phase of the spreading monocytes. In spread cells the punctate foci occupied the whole ventral surface of the cells, and in flattened, fully spread cells these proteins formed distinct punctate plaques at the under surface of the cells excluding however, the ruffle edge-like membrane regions. At the plaques, a close co-distribution of actin and vinculin was seen in double indirect immunofluorescence microscopy. Myosin showed a distinctly different reorganization during the transition process changing from a diffuse cytoplasmic location to a striated, surface-associated distribution. Interference reflection microscopy revealed large areas of close adhesion but no focal adhesion sites in spreading monocytes. Cytochalasin B treatment lead to a rapid distortion of the actin organization and resulted in clump-like cytoplasmic aggregates and nuclear paracrystals of actin concomitantly with the rounding up of the cells. Vimentin filaments were seen as a perinuclear aggregate until the acquisition of the fully spread morphology. At this stage both vimentin filaments and microtubules displayed a fibrillar appearance throughout the cytoplasmic domain. Treatment of the spread monocytes with antimitotic drugs caused a retraction of the cell from beyond the attachment plaques but had no effect on the punctate actin organization. The results show that in the monocyte-macrophage transition there is an extensive cytoskeletal reorganization that can be correlated with the different phases of the cell-to-substratum attachment process.

Actinin↗
PubMed1982

Epithelioid sarcoma. Ultrastructural and immunohistologic features suggesting a synovial origin.

A case of epithelioid sarcoma was studied light microscopically, ultrastructurally, and immunohistologically. The tumor was a deep antebrachial mass in a 57-year-old man, and led to antebrachial amputation. Light microscopically, the tumor consisted of nodules that often had central necrosis. The cells were uniform, with abundant eosinophilic or pale, translucent cytoplasm. Electron microscopic examination showed many filopodialike cytoplasmic surface extensions in many cells and occasional glandlike structures with specialized cell-to-cell junctions. The cytoplasm of some cells contained bundles of intermediate filaments that immunohistochemical examination showed to be of vimentin type. Some ultrastructural features resemble those of classic synovial sarcoma and the immunohistologic findings are identical with those of synovial cells, which may thus be the cell of origin of epithelioid sarcoma in this case.

Cytoskeleton↗
PubMed1981

Temperature-dependent and transformation-associated changes in polyamine metabolism in normal and Rous sarcoma virus-infected chick embryo fibroblasts.

Tertiary cultures of chick embryo fibroblasts infected and transformed by the wild-type Rous sarcoma virus, when actively growing at 35 degrees C, had higher putrescine levels than the respective uninfected cells. Transformed cells also had much higher specific activity of ornithine decarboxylase (EC 4.1.1.17) than the normal fibroblasts. At 41 degrees C the difference in putrescine levels between the normal and the transformed cells was less marked, and both cell types showed a relative accumulation of spermine. Cultures infected with the NY68 mutant virus, which is temperature-sensitive for transformation, showed at 41 degrees C normal cell morphology and intermediate polyamine patterns, while at 35 degrees C a transformed phenotype was found in both aspects. In shift-down experiments a change towards the permissive temperature pattern of polyamine metabolism was evident within 2-3 h. Difluoromethylornithine, a specific and irreversible inhibitor of ornithine decarboxylase efficiently reduced the enzyme activity as well as the levels of both putrescine and spermidine in all culture types and temperatures. Incubation of Rous sarcoma virus-transformed cells with 3 mM difluoromethylornithine for 36 h did not affect the maintenance of the transformed state. Likewise, when NY68-infected cultures were exposed to difluoromethylornithine at 41 degrees C for 12 h and then shifted down to 35 degrees C, the appearance of the transformed morphology took place concomitantly with that of the control cultures without respective changes in the polyamine levels. This suggests that the transformation-associated pattern of polyamines in chick embryo fibroblasts is not a prerequisite for morphological transformation of these cells.

Animals↗
PubMed1981

Glial and neuronal cells in amniotic fluid of anencephalic pregnancies.

Cultured amniotic fluid cells from four anencephalic pregnancies were characterized in indirect immunofluorescence (IIF) microscopy using specific antibodies against different types of cytoskeletal intermediate filaments. Most of the cells showed a fine fibrillar cytoplasmic fluorescence with antibodies against glial fibrillary acidic protein (GFA), indicating that amniotic fluid cells in anencephalic pregnancies are of glial origin. The GFA-positive cells were rapidly adhering and proliferating. They remained as the major cell type also in long term cultures, and could easily be recovered from liquid nitrogen without losing their GFA positivity. GFA-positive cells were pleomorphic in appearance, and occurred in several morphologically different shapes. Amniotic fluid from one of the anencephalic cases contained typical neuronal cells, which in IIF were GFA-negative but could specifically be stained with anti-neurofilament antibodies. Most of the GFA-negative cells in all the cases were fibroblasts, identified by their fluorescence only with antibodies against vimentin. Epithelial cells showing positive keratin-fluorescence in IIF, were seen only occasionally.

Adult↗