131 research outputs found

    Corporate Governance in Central and Eastern Europe: Transition management is a tough job

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    1) Financing Firms in East European Countries: An Asymmetric Information and Agency Costs Approach, by Debora Revoltella 2) Seven Years of Financial Market Reform in Central Europe, by Peter H. Haiss and Gerhard Fink

    SPECIFIC BINDING OF NERVE GROWTH FACTOR (NGF) BY MURINE C 1300 NEUROBLASTOMA CELLS

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    Murine C 1300 neuroblastoma cells bind with high avidity on their membrane surface the nerve growth factor (NGF), a protein capable of inducing differentiation of sympathetic nerve cells. The total binding capacity of NGF by the cells was quantitatively measured by a radioimmunoassay technique, using 125I-labeled NGF. An average number of about 106 molecules of NGF could be bound, at saturation, by each cell with an average relative association constant of about 107 liters/mol. Using synchronized cells, it was found, however, that either the number of molecules of ligand bound or the avidity of the binding interaction between NGF and cells varied depending upon their growth cycle, the maximal-binding occurring during the G1 and early S phase. Binding of [125I]NGF was suppressed by trypsin treatment of the cells, however new receptor sites were rapidly replaced onto the membrane surface within 1–2 h. Cells exposed to 3 M KCl released into the supernate a protein product exhibiting similar high avidity for NGF. Acrylamide gel electrophoresis suggested a restricted molecular heterogeneity of this product, with a major component in the 52,000 mol wt region. Antibodies made specific to this protein were capable, in the absence of the complement, of inhibiting the binding of [125I]NGF by the cells and in the presence of the complement they killed them

    Tumour-derived CSF2/granulocyte macrophage colony stimulating factor controls myeloid cell accumulation and progression of gliomas

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    BACKGROUND: Malignant tumours release factors, which attract myeloid cells and induce their polarisation to pro-invasive, immunosuppressive phenotypes. Brain-resident microglia and peripheral macrophages accumulate in the tumour microenvironment of glioblastoma (GBM) and induce immunosuppression fostering tumour progression. Macrophage colony stimulating factors (CSFs) control the recruitment of myeloid cells during peripheral cancer progression, but it is disputable, which CSFs drive their accumulation in gliomas. METHODS: The expression of CSF2 (encoding granulocyte-macrophage colony stimulating factor) was determined in TCGA datasets and five human glioma cell lines. Effects of stable CSF2 knockdown in glioma cells or neutralising CSF2 or receptor CSF2Rα antibodies on glioma invasion were tested in vitro and in vivo. RESULTS: CSF2 knockdown or blockade of its signalling reduced microglia-dependent glioma invasion in microglia-glioma co-cultures. CSF2-deficient human glioma cells encapsulated in cell-impermeable hollow fibres and transplanted to mouse brains, failed to attract microglia, but stimulated astrocyte recruitment. CSF2-depleted gliomas were smaller, attracted less microglia and macrophages, and provided survival benefit in tumour-bearing mice. Apoptotic microglia/macrophages were detected in CSF2-depleted tumours. CONCLUSIONS: CSF2 is overexpressed in a subset of mesenchymal GBMs in association with high immune gene expression. Tumour-derived CSF2 attracts, supports survival and induces pro-tumorigenic polarisation of microglia and macrophages

    Different effects of hybridoma antibodies against nerve growth factor in neonatal mice.

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    Reaginic antibody production in different mouse strains

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    Mice of several strains were immunized with DNP-haemocyanin either with Al(OH)(3) or with Freund's complete adjuvant. Antibodies of immunoglobulin type γ(2) and γM were detected by passive haemolysis, γ(2a) antibodies by PCA in guinea-pigs, γ(1) antibodies by PCA in mice using 2 hours of SP, and reaginic antibodies by PCA in mice using 72 hours of SP. Three of the six strains tested produced reaginic antibodies, i.e. SWR/J, C57BL/6J and A/HeJ, but only when Al(OH)(3) was used as adjuvant. All six strains produced γ(1) antibodies. Reaginic antibodies were separated by chromatography on DEAE-cellulose column

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    Abstract. A 3D culture system was used to investigate the behaviour of mesothelial cells present in the wall of human processus vaginalis peritonei. Small tissue fragments placed on collagen sponges were cultured for 7, 14 and 21 days in medium supplemented with 10% FBS, and analysed for the expression and distribution of cytokeratins (CKAE1-AE3, CK19), p63, Ki-67, vimentin, CD34, and HBME-1. Before culture, flat mesothelial cells displayed immunoreactivity for cytokeratins, vimentin and HBME-1, while p63 and CD34 were negative. Mesenchymal cells within the stroma were vimentin-positive and endothelial cells of small vessels displayed positive staining for CD34. Cytokeratins, p63 and HBME-1 were negative in all stromal cells. In cultured fragments, flat mesothelial cells positive for vimentin, cytokeratins and HBME-1 proliferated, lining the fragment surface and migrating into the sponge. Capillaries showed morphological alterations; however, their immunoreactivity was comparable with the stroma prior to culture. Cells that had migrated into the sponge and displayed characteristics of mesothelial progenitors, predominantly spindleshaped and stellate, showed heterogeneous expression of markers especially in late phases of cultivation. These cells were constantly positive for vimentin, a small fraction was cytokeratin-positive and a few displayed HBME-1 immunoreactivity. CD34 was found in cells forming small cavities into the matrix, resembling newly formed blood vessels. Cells that had migrated into the sponge could be isolated and expanded in coculture with feeder NIH.3T3 fibroblasts. This system is suitable for studying growth and behaviour of mesothelial cells within their natural environment, providing a good method for isolation and expansion of their progenitor cells
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