Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1573-7039
    Keywords: BRANCHING MORPHOGENESIS ; CORTICOSTEROIDS ; EPITHELIAL-MESENCHYMAL INTERACTIONS ; EXTRACELLULAR MATRIX ; HEPATOCYTE GROWTH FACTOR/SCATTER FACTOR ; LUMEN FORMATION ; MAMMARY GLAND ; c-MET ; TRANSFORMING GROWTH FACTOR-β
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Epithelial-mesenchymal interactions areresponsible for the unique pattern of ductal branchingmorphogenesis characteristic of the mammary gland. Toinvestigate the factors which control the elongation and branching of lactiferous ducts, wedeveloped an in vitro model of ductal morphogenesis inwhich clonal mouse mammary epithelial cells (TAC-2cells) are grown in collagen gels. In this experimentalsystem, fibroblast conditioned medium (CM)3stimulates the formation of extensively arborizedtubules. The molecule responsible for this tubulogeniceffect was identified as hepatocyte growthfactor/scatter factor (HGF/SF). To determine whether HGF/SF plays arole in mammary gland morphogenesis in vivo, theexpression of HGF/SF and its receptor, cMet, wereanalyzed in the rat mammary gland during pregnancy,lactation, and involution. Levels of HGF/SF and c-Mettranscripts were progressively reduced during pregnancy,were virtually undetectable during lactation, andincreased again during involution. Collectively, these in vitro and in vivo findings suggest thatHGF/SF is a paracrine mediator of mammary gland ductalmorphogenesis. We subsequently investigated the effectof another multifunctional cytokine, namely TGF-beta1, on branching morphogenesis of TAC-2 cells.TGF-β1 had a striking biphasic effect:whereas relatively high concentrations of this cytokineinhibited colony formation, lower concentrationsstimulated extensive elongation and branching of epithelial cords.Taken together, these studies indicate that HGF/SF is astromal-derived paracrine mediator of mammary ductalmorphogenesis, and that when present at lowconcentrations, TGF-β1 can contribute to thisprocess.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] We have shown previously that fractionated human urine contains substances capable of inhibiting cell proliferation and angiogenesis6'7. Two of the most potent fractions contained cate-cholic and non-polar oestrogen metabolites, suggesting their involvement in the oestrogen-dependent regulation of ...
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 370 (1994), S. 14-15 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] THE extracellular matrix is an intricate mesh of proteinaceous fibres and carbohydrate macromolecules which must be crossed by cancer cells before they can invade tissues and metastasize. Proteolytic enzymes at the plasma membrane are likely accomplices in these processes, focusing degradative ...
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1573-7373
    Keywords: medulloblastoma ; microvessel counts ; immunohistochemistry ; p53 ; bcl-2 ; Mib-1 ; factor VIII-related antigen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of this study was to retrospectively assess the prognostic value of p53 and bcl-2 protein expression, cell proliferation index (Mib-1 index), and tumor microvessel density (factor VIII-related antigen) in pediatric medulloblastoma patients. Tumor specimens of 55 patients (age 2–18 years) with medulloblastoma treated with a curative intent between 1972 and 1991 were studied. Slides of paraffin embedded tissue were stained with monoclonal antibodies (mAb) and examined under high power light microscopy for the presence of immunoreactivity. Microvessel density was scored both in the area of most intense staining (‘Angio-max’) and in 3 additional randomly selected areas. The sum of these 4 scores was termed ‘Angio-total’. ‘Angio-max’ and ‘Angio-total’ were evaluated separately by two independent investigators to assess reproducibility. None of the parameters studied, i.e. p53 or bcl-2 expression, Mib-1 index or microvessel density scores were associated with patient survival. Microvessel scores between observers were significantly but weakly correlated, with correlation coefficients (r)〈0.5 for both ‘Angio-max’ and ‘Angio-total’. Leptomeningeal spread at diagnosis was the only independent factor associated with a poor survival (p=0.003). There was no association of leptomeningeal metastasis with any of the biological markers tested in this study.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Vascular endothelial growth factor-C (VEGF-C) is a recently characterized member of the VEGF family of angiogenic polypeptides. We demonstrate here that VEGF-C is angiogenic in vitro when added to bovine aortic or lymphatic endothelial (BAE and BLE) cells but has little or no effect on bovine microvascular endothelial (BME) cells. As reported previously for VEGF, VEGF-C and basic fibroblast growth factor (bFGF) induced a synergistic in vitro angiogenic response in all three cells lines. Unexpectedly, VEGF and VEGF-C also synergized in the in vitro angiogenic response when assessed on BAE cells. Characterization of VEGF receptor (VEGFR) expression revealed that BME, BAE, and BLE cell lines express VEGFR-1 and -2, whereas of the three cell lines assessed, only BAE cells express VEGFR-3. We also demonstrate that VEGF-C increases plasminogen activator (PA) activity in the three bovine endothelial cell lines and that this is accompanied by a concomitant increase in PA inhibitor-1. Addition of α2-antiplasmin to BME cells co-treated with bFGF and VEGF-C partially inhibited collagen gel invasion. These results demonstrate, first, that by acting in concert with bFGF or VEGF, VEGF-C has a potent synergistic effect on the induction of angiogenesis in vitro and, second, that like VEGF and bFGF, VEGF-C is capable of altering endothelial cell extracellular proteolytic activity. These observations also highlight the notion of context, i.e., that the activity of an angiogenesis-regulating cytokine depends on the presence and concentration of other cytokines in the pericellular environment of the responding endothelial cell. J. Cell. Physiol. 177:439-452, 1998. © 1998 Wiley-Liss, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 0730-2312
    Keywords: PDGF ; PDGF receptor ; cell migration ; endothelial cell ; endothelium ; angiogenesis ; in vitro ; urokinase-type plasminogen activator ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: To explore direct effects of platelet-derived growth factor (PDGF) on endothelial cells during angiogenesis in vitro, we have used cloned bovine aortic endothelial cells that spontaneously form cord structures. Recently we have shown that cells forming these endothelial cords express PDGF β-receptors and that PDGF-BB can contribute to cellular proliferation and cord formation. In this study we investigated whether PDGF-induced cellular migration might also contribute to endothelial repair and angiogenesis in vitro.Ten individual endothelial cells in cords were tracked at an early stage of cord formation by video-timelapse microscopy. PDGF-BB (100 ng/ml) induced an increase in endothelial cell movement of 67 ± 15% as compared with diluent control. Interestingly, PDGF-BB also increased movements of entire cord structures, followed at branching points, by 53 ± 12% over diluent control. Taken together, these video-timelapse experiments suggested that the apparent movements of single endothelial cord cells might also be due to the motion of entire underlying cord structures in response to PDGF. To analyze the response of single endothelial cord cells we therefore examined whether PDGF-induced migration contributes to endothelial repair. Abrasions were applied with a razor blade to confluent monolayers of endothelial cells at an intermediate stage of cord formation. PDGF-BB concentration-dependently increased the distance to which cord-forming endothelial cells migrated into the abrasion. An increased number of elongated, i.e., probably migrating, endothelial cells was found in the abrasion in response to PDGF-BB. However, there was no effect of PDGF-BB on the total number of endothelial cells found in the abrasion. PDGF-AA affected neither the distance to which the cells migrated nor the number of elongated cells.Actin and tubulin stainings revealed that these cytoskeletal structures were not appreciably altered by PDGF-BB. Furthermore, urokinase-type plasminogen activator transcripts were not modulated in response to PDGF-BB.We conclude that in this model of angiogenesis in vitro PDGF-BB can elicit the movement of entire cord structures, possibly via u-PA-independent mechanisms. PDGF-BB also controls the migration of single cord-forming endothelial cells. Thus, PDGF-BB possibly contributes to endothelial repair and angiogenesis by direct effects on proliferation and composite movements of PDGF β-receptor-expressing endothelial cells and cords. J. Cell. Biochem. 64:403-413. © 1997 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...