Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Pectin-coated titanium implants are well-tolerated in vivo
    Kokkonen, H. ; Niiranen, H. ; Schols, H.A. ; Morra, M. ; Stenback, F. ; Tuukkanen, J. - \ 2010
    Journal of Biomedical Materials Research Part A 93A (2010)4. - ISSN 1549-3296 - p. 1404 - 1409.
    enzymatically-tailored pectins - resistant acid-phosphatase - hairy regions - citrus pectin - cell - fibroblasts - degradation - expression - responses - adhesion
    Multiform coated titanium implants are widely used in orthopedic and dental surgery. In this study, we have investigated the reactivity of pectin-coated titanium samples implanted under the latissimus dorsi—muscle fascia of rats. Samples were coated with two enzyme treated apple pectins; modified hairy regions (MHR-A and MHR-B) that differed in chemical structure. Aminated (AMI) and uncoated titanium (Ti) served as controls. The thicknesses of the peri-implant fibrous tissue capsules formed 1 or 3 weeks after implantation were measured as indicative of possible inflammatory reactions toward the biomaterials. After 1 week, the MHR-B implant was surrounded by a thicker fibrous capsule (42.9 µm) than any of the other sample types: MHR-A (33.2 µm), AMI (32.5 µm), and Ti (32.3 µm), the last one being the only statistically significant difference. After 3 weeks, however, this difference disappeared; the capsule thicknesses around MHR-B and Ti implants had decreased to the values found for AMI and MHR-A. Additionally, the capsule formation represents merely a stromal rather than an inflammatory reaction, as indicated by the absence of activated macrophages or foreign body giant cells in the capsules. These results indicate for the first time the in vivo tolerability of covalently linked pectins, and suggest the feasibility of pectin-coated bone and dental implants for clinical use.
    Differentiation of osteoblasts on pectin-coated titanium
    Kokkonen, H. ; Cassinelli, C. ; Verhoef, R. ; Morra, M. ; Schols, H.A. ; Tuukkanen, J. - \ 2008
    Biomacromolecules 9 (2008)9. - ISSN 1525-7797 - p. 2369 - 2376.
    in-vitro - hairy regions - extracellular-matrix - protein adsorption - gene-expression - mc3t3-e1 cells - stromal cells - mineralization - proliferation - attachment
    The gold standard for implant metals is titanium, and coatings such as collagen-I, RGD-peptide, chondroitin sulfate, and calcium phosphate have been used to modify its biocompatibility. We investigated how titanium coated with pectins, adaptable bioactive plant polysaccharides with anti-inflammatory effects, supports osteoblast differentiation. MC3T3-E1 cells, primary murine osteoblasts, and human mesenchymal cells (hMC) were cultured on titanium coated with rhamnogalacturonan-rich modified hairy regions (MHR-A and MHR-B) of apple pectin. Alkaline phosphatase (ALP) expression and activity, calcium deposition, and cell spreading were investigated. MHR-B, but not MHR-A, supports osteoblast differentiation. The MHR-A surface was not mineralized, but on MHR-B, the average mineralized area was 14.0% with MC3T3-E1 cells and 26.6% with primary osteoblasts. The ALP activity of hMCs on MHR-A was 58.3% at day 7 and 9.3% from that of MHR-B at day 10. These data indicate that modified pectin nanocoatings may enhance the biocompatibility of bone and dental implants.
    Modulation of fibroblast behaviour by enzymatically-tailored pectins: PectiCoat
    Nagel, M.D. ; Vigneron, P. ; Bussy, C. ; Vayssade, M. ; Duval, J.L. ; Gallet, M. ; Dufresne, M. ; Verhoef, R.P. ; Morra, M. ; Knox, J.P. ; Schols, H.A. ; Ceccone, G. ; Volpe, C. Della - \ 2008
    Computer methods in biomechanics and biomedical engineering 11 (2008)Suppl. 1. - ISSN 1025-5842 - p. 171 - 172.
    hairy regions
    Effect of Modified Pectin Molecules on the Growth of Bone Cells
    Kokkonen, H.E. ; Ilvesaro, J.M. ; Morra, M. ; Schols, H.A. ; Tuukkanen, J. - \ 2007
    Biomacromolecules 8 (2007)2. - ISSN 1525-7797 - p. 509 - 515.
    calvarial osteoblast differentiation - protein adsorption - hairy regions - coated surfaces - polysaccharide - osteoclasts - fibronectin - resorption - attachment - adhesion
    The aim of this study was to investigate molecular candidates for bone implant nanocoatings, which could improve biocompatibility of implant materials. Primary rat bone cells and murine preosteoblastic MC3T3-E1 cells were cultured on enzymatically modified hairy regions (MHR-A and MHR-B) of apple pectins. MHRs were covalently attached to tissue culture polystyrene (TCPS) or glass. Uncoated substrata or bone slices were used as controls. Cell attachment, proliferation, and differentiation were investigated with fluorescence and confocal microscopy. Bone cells seem to prefer MHR-B coating to MHR-A coating. On MHR-A samples, the overall numbers as well as proportions of active osteoclasts were diminished compared to those on MHR-B, TCPS, or bone. Focal adhesions indicating attachment of the osteoblastic cells were detected on MHR-B and uncoated controls but not on MHR-A. These results demonstrate the possibility to modify surfaces with pectin nanocoatings.
    Enzymatic degradation studies of xylogalacturonans from apple and potato, using xylogalacturonan hydrolase
    Zandleven, J.S. ; Beldman, G. ; Bosveld, M. ; Schols, H.A. ; Voragen, A.G.J. - \ 2006
    Carbohydrate Polymers 65 (2006)4. - ISSN 0144-8617 - p. 495 - 503.
    aspergillus-aculeatus - pectic substances - hairy regions - polysaccharides
    Action of xylogalacturonan hydrolase (XGH) towards xylogalacturonan (XGA) present in the alkali saponified ¿modified hairy regions¿ from potato and apple pectin was studied. Analysis of enzymatic degradation products from XGA in these complex pectins demonstrated that the degradable xylogalacturonans from both sources have a similar xylose side chain distribution. The disaccharide ß-d-Xyl-(1,3)-GalA was the predominant product from these substrates. The number of enzymatic degradation products from xylogalacturonan present in apple and potato pectin was much lower than the number of products from a xylogalacturonan derived from Gum Tragacanth. This suggests a relatively uniform distribution of xylose in the degradable part of XGA from apple and potato pectin. In addition, dimeric side chains of xylose were observed in digests of XGA from both pectins, which apparently did not hinder the action of XGH. From this it is assumed that Xyl¿Xyl as well as Xyl substituted GalA residues are accepted in subsite ¿1 of xylogalacturonan hydrolase
    Carrot arabinogalactan proteins are interlinked with pectins.
    Immerzeel, P. ; Eppink, M.M. ; Vries, S.C. de; Schols, H.A. ; Voragen, A.G.J. - \ 2006
    Physiologia Plantarum 128 (2006)1. - ISSN 0031-9317 - p. 18 - 28.
    cell-wall polysaccharides - daucus-carota - hairy regions - arabidopsis - suspension - plants - substances - culture - family - pulp
    Cell wall extracts from a carrot cell culture and tap roots were obtained by sequential extraction with water, EDTA buffer solution and cold sodium hydroxide solution. Arabinogalactan proteins (AGPs) were isolated from the extracts and from the medium of the cell culture and analysed for their molecular weight distribution and carbohydrate composition. Copper ions were used to separate the Yariv positive fractions into AGP fractions with a high and a low level of galacturonic acid (GalA). The GalA rich AGP fractions were incubated with pectin methylesterase and polygalacturonase. This enzyme incubation released GalA fragments from the AGP fractions as monitored by HPAEC and MALDI-TOF MS. At least part of carrot AGPs from the medium and cell walls may be covalently linked to pectin containing a homogalacturonan structural element.
    A xylogalacturonan epitope is specifically associated with plant cell detachment.
    Willats, W.G.T. ; McCartney, L. ; Steele-King, C.G. ; Marcus, S.E. ; Mort, A.J. ; Huisman, M.M.H. ; Alebeek, G.J.W.M. van; Schols, H.A. ; Voragen, A.G.J. ; Goff, A. le; Bonnin, E. ; Thibault, J.F. ; Knox, J.P. - \ 2004
    Planta 218 (2004)4. - ISSN 0032-0935 - p. 673 - 681.
    pectic polysaccharides - spatial regulation - hairy regions - pea hulls - walls - homogalacturonan - tomato - cotyledons - separation - pericarp
    A monoclonal antibody (LM8) was generated with specificity for xyloglacturonan (XGA) isolated from pea (Pisum sativum L.) testae. Characterization of the LM8 epitope indicates that it is a region of XGA that is highly substituted with xylose. Immunocytochemical analysis indicates that this epitope is restricted to loosely attached inner parenchyma cells at the inner face of the pea testa and does not occur in other cells of the testa. Elsewhere in the pea seedling, the LM8 epitope was found only in association with root cap cell development at the root apex. Furthermore, the LM8 epitope is specifically associated with root cap cells in a range of angiosperm species. In embryogenic carrot suspension cell cultures the epitope is abundant at the surface of cell walls of loosely attached cells in both induced and non-induced cultures. The LM8 epitope is the first cell wall epitope to be identified that is specifically associated with a plant cell separation process that results in complete cell detachment.
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