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  • 1
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science Inc
    Wound repair and regeneration 9 (2001), S. 0 
    ISSN: 1524-475X
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Phospholipase C secreted by bacterial pathogens has been identified as a virulence factor in several human diseases and has been implicated in impeding wound healing. The role of phospholipase C in the intracellular signal control of epithelial growth was studied in normal human skin keratinocytes cultured in conditions simulating aspects of wound healing. Bacillus cereus phospholipase C decreased cell-cell contact and increased cell migration resulting in disruption of the advancing epithelial sheet. Phospholipase C-induced migration was blocked by inhibitor of the phosphoinositol signal transduction pathway neomycin sulfate and protein kinase C inhibitor RO-31–8220. Induced migration was associated with elevated levels of matrix metalloproteinase-9 which, when blocked by tissue inhibitor of metalloproteinase-1, was accompanied by a loss of migration. Adhesion studies showed that phospholipase C treatment enhanced cell binding to fibronectin, vitronectin and collagen IV. Immunostained phospholipase C-stimulated cells cultured on fibronectin showed enhanced expression and relocation of the integrin subunits αv, α5 and β1. Confocal microscopy showed that phospholipase C-induced levels of integrin subunit β1 were predominantly deposited on the basal surface of the cell apparently in focal contacts and associated with actin stress fibers. These results indicate that exogenous phospholipase C signaling from a bacterial source may play an important role in perturbing normal reepithelialization via altered expression of integrins and matrix metalloproteinase-9.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 732 (1994), S. 0 
    ISSN: 1749-6632
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Allgemeine Naturwissenschaft
    Materialart: Digitale Medien
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  • 3
    ISSN: 1600-0765
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: A chymotrypsin-like enzyme was partially purified from culture medium of epithelial cells of human skin, human gingiva and porcine periodontal ligament by aprotinin-affinity chromatography. The enzyme levels from all three cell types were low in quiescent cultures but increased markedly when the cells were allowed to proliferate. The biphasic elution profile of the enzyme from the affinity column closely matched that of α-chymotrypsin and the protein comigrated with it on polyacrylamide gels at 27,000 M Synthetic substrate tests of purified fractions showed strong chymotrypsin-like but no trypsin-like or elastase-like activity. Inhibition of protease activity and pH optimum in the range of 7.5–8.0 were consistent with chymotrypsin-like enzymes. Secreted activity was found to be significantly increased by phorbol myristate acetate treatment in a time-course that differed from that of elastase-like activity. Keratinocyte growth factor and epidermal growth factor but not transforming growth factor-β increased the chymotrypsin-like activity in a concentration-dependent manner. The enzyme secretion by epithelial cells was strongly elevated by exposure to 5 of 6 Actinobacillus actinomycetemcomitans strains isolated from plaque samples of juvenile periodontitis patients. These results indicate that chymotrypsin-like enzymes are secreted by proliferative phenotypes of normal epithelial cells. This enzyme may, therefore, play a role in epithelial physiology and in cell response to certain pathogenic bacteria.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Munksgaard International Publishers
    Journal of periodontal research 40 (2005), S. 0 
    ISSN: 1600-0765
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Objectives:  Keratinocyte growth factor-1 (KGF-1) is up-regulated in chronic inflammation and specifically stimulates epithelial cell proliferation by signaling through the epithelial-specific keratinocyte growth factor receptor (KGFR). We examined KGF-1 and KGFR protein and gene expression in healthy and diseased periodontal tissues.Methods:  Tissues were collected from patients with periodontal health or disease, immediately frozen and stained for KGF-1 and KGFR protein expression. Laser capture microdissection of epithelial and connective tissue cells with reverse transcription–polymerase chain reaction (RT–PCR) examined KGF-1 and KGFR gene expression profiles and enzymatic digestion with heparitinase, chondroitinase ABC or pre-treatment with suramin examined epithelial surface molecule interactions with KGF-1.Results:  In tissues collected from healthy patients, KGF-1 protein localized to areas of junctional and basal oral epithelial cells and was significantly increased in periodontal pocket epithelium (p 〈 0.01) and in the oral epithelium (p 〈 0.05) of disease-associated tissues. KGFR localized to the junctional and the parabasal cells of oral epithelium, with the relative staining intensity being increased in disease-associated pocket epithelium (p 〈 0.05). Laser capture microdissection with RT–PCR confirmed KGF-1 and KGFR were specifically expressed by connective tissue and epithelium, respectively. KGF-1 localization to epithelial cells was largely eliminated by suramin pre-treatment, indicating interaction with the KGFR.Conclusions:  KGF-1 and KGFR proteins are expressed in healthy periodontal tissues but significantly increased in diseased periodontal tissues. We hypothesize up-regulation of KGF-1 and KGFR protein associated with disease regulates epithelial cell behavior associated with onset and progression of periodontal pocket formation.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Copenhagen : Munksgaard International Publishers
    Journal of periodontal research 37 (2002), S. 0 
    ISSN: 1600-0765
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The onset and progression of jreiodontal disease is associated with significant changes in the epithelial component of the attachment complex. From the early to the advanced stages of jreiodontal disease increased epithelial cell proliferation, migration and invasion into the surrounding connective tissue takes place. Concomitantly there is a significant increase in proinflammatory cytokine expression in jreiodontal tissue and quantitative and qualitative changes in the subgingival microflora, including an increase in gram-negative microorganisms. One of the most significant virulence factors of these bacteria is lipopolysaccharide (LPS) connected to the outer membrane. Two important growth factors controlling epithelial behavior are Keratinocyte Growth Factor-1 (KGF-1) and -2 (KGF-2). Connective tissue cells express these growth factors, but only epithelial cells respond to them. We studied the effect of proinflammatory cytokines and LPS on gingival fibroblast expression of KGF-1 and KGF-2 in vitro. Gingival fibroblasts were found to express KGF-1 and -2 in culture but only KGF-1 protein and gene expression was stimulated by serum, in a concentration-dependent manner by proinflammatory cytokines IL-1α, IL-1β, TNF-α and IL-6 and LPS isolated from Porphyromonas gingivalis and Escherichia coli. The local increase in proinflammatory cytokine expression and the accumulation of LPS in disease sites may therefore stimulate gingival fibroblast expression of KGF-1. We hypothesize that this local increase in KGF-1 expression may, via a paracrine mechanism, stimulate local epithelial cell proliferation, migration and invasion during the onset and progression of jreiodontitis.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 31 (1996), S. 209-217 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The effects of commercially pure titanium (Ti) on the regulation of fibronectin gene expression and synthesis were investigated in early-passage human gingival fibroblasts. The fibroblasts were cultured on 50 nm Ti-coated silicon wafers treated with radio-frequency glow discharge prior to use and on Falcon tissue culture plastic (TCP) dishes as a control. Northern hybridization analysis revealed that fibroblasts cultured on Ti reduced the fibronectin mRNA level by 58% at 16 h, but increased it by 2.6-fold at 90 h, although the cell numbers and house-keeping gene GAPD mRNA levels on these two surfaces were essentially the same. The amount of total RNA was slightly less on the Ti surface. While the total [35S]methionine incorporation was essentially unaltered, the amount of [35S]methionine-labeled fibronectin was significantly increased in cells cultured on a Ti surface in early cultures but decreased in the late cultures. The apparent discrepancy between the increased fibronectin mRNA levels and decreased translation could be explained by a 30% reduction in fibronectin mRNA half life in cells cultured on Ti. The distribution of fibronectin between the medium and the cell layer also was altered on Ti surfaces, with a ∼100-fold increase of fibronectin assembled in extracellular matrix at 16 h, but a 36% reduction at 90 h. In contrast, the amount of fibronectin recovered in the medium was essentially unchanged. The total amount of protein assembled into the extracellular matrix by cells on Ti increased 2.1-fold at 16 h but decreased by 19% in 90-h cultures. These significant changes in fibronectin gene activity and gene product distribution by cells cultured on Ti surfaces demonstrate that the surface chemistry of biomaterials can selectively regulate the cellular behavior at the molecular level and, conversely, that molecular biological techniques provide sensitive indicators of the molecular biocompatibility of implant materials. © 1996 John Wiley & Sons, Inc.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 39 (1998), S. 437-445 
    ISSN: 0021-9304
    Schlagwort(e): titanium ; surface topography ; MMP-2 ; molecular biocompatability ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The chemical and topographic effects of commercially pure titanium on cell morphology and the regulation of matrix metalloproteinase-2 (MMP-2) gene expression, synthesis, and activity were investigated in early passage human gingival fibroblasts. Scanning electron microscopy showed that on smooth titanium (Ti), fibroblasts remained well spread and randomly oriented throughout the culture period. In contrast, cells on V-shaped grooved titanium (VTi) were oriented along the grooves by 16 h and proliferated in this organization throughout the culture period. The effects of substratum surface chemistry on MMP-2 expression were found to be distinct from those of topography. Northern hybridization analysis of fibroblasts cultured on Ti revealed an MMP-2 mRNA time-course expression pattern parallel to that observed on the tissue culture plastic (TCP) dishes, but at significantly lower levels at each time-point. The Ti mRNA levels were decreased by 34% at 16 h, 55% at 40 h, and 45% at 90 h relative to TCP. In contrast, MMP-2 mRNA expression on VTi showed both an altered time-course expression pattern and altered levels compared to Ti and TCP. Relative to TCP, VTi MMP-2 mRNA levels were ∼80% less at 16 h and ∼50% less at 40 h, but not significantly different at 90 h. Relative to Ti, VTi MMP-2 mRNA levels were ∼75% less at 16 h, but ∼40% greater at 40 h and ∼70% greater at 90 h. These differences may be explained in part by the observed changes in MMP-2 mRNA half-life which decreased by ∼40% on Ti but increased by over fourfold on VTi relative to TCP. The smooth Ti also showed an approximate twofold increase of MMP-2 secretion in the late cultures over TCP controls. These results indicate that substratum surface chemistry and topography-induced changes in cell shape can alter MMP-2 expression in normal fibroblasts. The molecular approach to investigating the major molecules involved in tissue degradation may provide sensitive indicators of tissue remodeling at the tissue-biomaterial interface. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 39, 437-445, 1998.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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