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  • 1
    Electronic Resource
    Electronic Resource
    Regulation of Avian Osteopontin Pre-and Posttranscriptional Expression in Skeletal Tissues (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 760 (1995), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1995.tb44621.x
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  • 2
    Electronic Resource
    Electronic Resource
    Immunoblotting studies on artifactual contamination of enamel homogenates by albumin and other proteins (1995)
    Springer
    Calcified tissue international 57 (1995), S. 145-151 
    Details
    ISSN: 1432-0827
    Keywords: Enamel proteins ; Amelogenin ; Ameloblasts ; Albumin ; Immunoblotting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The reason for the presence of albumin and other serum, cytoskeletal, cytosolic, and extracellular matrix proteins in enamel fractions was investigated by immunoblotting using homogenates prepared from freeze-dried and freshly dissected rat incisors, and antibodies capable of resolving at least 1 ng of the primary antigen. The data indicated that most of the 16 antibodies examined in this study reacted with antigens present only within “cell” homogenates (enamel organ cells+adhering labial connective tissue and blood vessels). One exception was rat serum albumin which was detected routinely in enamel homogenates prepared from freshly dissected, wiped incisors but rarely within enamel homogenates prepared from freeze-dried incisors. Another exception was calbindin-D 28 kDa which was consistently found within secretory stage enamel homogenates irrespective of preparative technique. A third exception was enamel proteins (amelogenins) which were enriched in secretory and early maturation stage enamel homogenates compared with cell homogenates and distributed as multiple molecular weight, antigenic bands in enamel homogenates (14–30 kDa), but mostly as a single antigenic band in cell homogenates (near 27 kDa). Overall, the results of this study suggest that developing rat incisor enamel naturally contains few exogenous proteins such as albumin. High concentrations of albumin (or other serum proteins) in crude homogenates, or purified fractions, derive mostly from blood and/or tissue fluids soaking into the enamel during sample preparation. This type of artifact can be avoided by using freeze-dried teeth for biochemical analyses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298435
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  • 3
    Electronic Resource
    Electronic Resource
    Cytochemical characterization of basement membranes in the enamel organ of the rat incisor (1993)
    Springer
    Histochemistry and cell biology 99 (1993), S. 321-331 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Ameloblasts are unique epithelial cells, in that once they have deposited the entire thickness of enamel and the process of maturation begins, they reform a basal lamina-like structure at their apical surface. In order to characterize further this basal lamina, its composition was analysed using (1) lectin-gold cytochemistry for glycoconjugates, (2) high-iron diamine (HID) staining for sulfated glycoconjugates and (3) immunogold labeling for collagen type IV and laminin. The labeling patterns were compared to that of other more “typical” basement membranes found in the enamel organ. Sections of rat incisor enamel organs embedded in Lowicryl K4M were stained with Helix pomatia agglutinin (HPA), Ricinus communis I agglutinin (RCA), wheat germ agglutinin (WGA) and Ulex europaeus I agglutinin (UEA). Samples from the late maturation stage were also reacted en bloc with lectins and embedded in Epon for transmission electron microscopic examination or prepared for scanning electron microscopy. Such samples were also stained with HID and conventionally processed for Epon embedding. Tissue sections were then reacted with thiocarbohydrazide-silver proteinate (TCH-SP). Analysis of the lectin labeling suggested that the region of extracellular matrix immediately adjacent to ameloblasts, where the basal lamina is situated, was intensely reactive with HPA and RCA, moderately reactive with WGA, and weakly reactive with UEA. In general, other basement membranes were mildly reactive with all lectins used. No HID-TCH-SP staining was observed directly over the basal lamina while numerous stain deposits were present over other basement membranes of the enamel organ. Immunolocalization of collagen type IV and laminin yielded a weak and variable labeling over the basal lamina. These results are consistent with the concept of basement membrane heterogeneity and, although the precise nature and composition of the basal lamina associated with maturation stage ameloblasts remain to be determined, they suggest that it may possibly function as a specialized basement membrane with particular compositional characteristics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00269105
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  • 4
    Electronic Resource
    Electronic Resource
    Bone sialoprotein mRNA expression and ultrastructural localization in fetal porcine calvarial bone: comparisons with osteopontin (1994)
    Springer
    Journal of molecular histology 26 (1994), S. 67-78 
    Details
    ISSN: 1573-6865
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Bone sialoprotein (BSP) and osteopontin (OPN) are two major non-collagenous proteins in bone that have similar biochemical properties and can mediate cell attachment through an RGD (Arg-Gly-Asp) motif that recognizes the vitronectin receptor. To facilitate evaluations of the biological functions of BSP and OPN in bone formation, affinity-purified rabbit polyclonal antibodies against porcine BSP and OPN were used, together with a high-resolution protein A-gold immunocytochemical technique to reveal the ultrastructural localization of these proteins in undermineralized sections of 50-day fetal porcine calvarial bone. In addition, 35S-labelled antisense riboprobes were prepared to demonstrate the cellular expression of BSP and OPN in the same tissues using in situ hybridization. Immunolocalization for both BSP and OPN revealed the highest density of gold particles associated with electron-dense organic material found at the mineralization front and in ‘cement lines’. Labelling was also observed in the mineralized matrix over electron-dense material between collagen fibrils. In the osteoid of newly-formed bone, immunogold labelling for BSP and OPN was associated with loci of mineralization, which were often characterized by feathery clusters of fine needle-like crystals. Results of in situ hybridization on the same tissues demonstrated that BSP mRNA expression was restricted to differentiated osteoblasts with particularly strong signals evident at sites of de novo bone formation. More moderate expression of BSP was observed in ‘older’ osteoblasts and in some of the newly-entrapped osteocytes. Although expression of OPN mRNA was also observed in osteoblasts and osteocytes, the level of hybridization was similar for most bone cells and not markedly stronger than the signal observed in some stromal cells. While it is evident from these and other studies that both BSP and OPN are associated with bone formation, the differences observed in cellular expression indicate distinct roles for these proteins in bone formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209251
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  • 5
    Electronic Resource
    Electronic Resource
    Bone sialoprotein mRNA expression and ultrastructural localization in fetal porcine calvarial bone: comparisons with osteopontin (1994)
    Springer
    Journal of molecular histology 26 (1994), S. 67-78 
    Details
    ISSN: 1573-6865
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Bone sialoprotein (BSP) and osteopontin (OPN) are two major non-collagenous proteins in bone that have similar biochemical properties and can mediate cell attachment through an RGD (Arg-Gly-Asp) motif that recognizes the vitronectin receptor. To facilitate evaluations of the biological functions of BSP and OPN in bone formation, affinity-purified rabbit polyclonal antibodies against porcine BSP and OPN were used, together with a high-resolution protein A-gold immunocytochemical technique to reveal the ultrastructural localization of these proteins in undermineralized sections of 50-day fetal porcine calvarial bone. In addition,35S-labelled antisense riboprobes were prepared to demonstrate the cellular expression of BSP and OPN in the same tissues usingin situ hybridization. Immunolocalization for both BSP and OPN revealed the highest density of gold particles associated with electron-dense organic material found at the mineralization front and in ‘cement lines’. Labelling was also observed in the mineralized matrix over electron-dense material between collagen fibrils. In the osteoid of newly-formed bone, immunogold labelling for BSP and OPN was associated with loci of mineralization, which were often characterized by feathery clusters of fine needle-like crystals. Results ofin situ hybridization on the same tissues demonstrated that BSP mRNA expression was restricted to differentiated osteoblasts with particularly strong signals evident at sites ofde novo bone formation. More moderate expression of BSP was observed in ‘older’ osteoblasts and in some of the newly-entrapped osteocytes. Although expression of OPN mRNA was also observed in osteoblasts and osteocytes, the level of hybridization was similar for most bone cells and not markedly stronger than the signal observed in some stromal cells. While it is evident from these and other studies that both BSP and OPN are associated with bone formation, the differences observed in cellular expression indicate distinct roles for these proteins in bone formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02388394
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  • 6
    Electronic Resource
    Electronic Resource
    Postembedding colloidal-gold immunocytochemistry of noncollagenous extracellular matrix proteins in mineralized tissues (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 44-62 
    Details
    ISSN: 1059-910X
    Keywords: Mineralization ; Bone ; Cartilage ; Cementum ; Dentin ; Enamel ; Osteopontin ; Osteocalcin ; Bone sialoprotein ; Amelogenin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Immunocytochemistry is a powerful tool for investigating protein secretion, extracellular matrix assembly, and cell-matrix and matrix-matrix/mineral relationships. When applied to the tissues of bones (bone and calcified cartilage) and teeth (dentin, cementum, and enamel), where calcium phosphate-containing extracellular matrices are the predominant structural component related to their weight-bearing and masticatory roles, respectively, data from immunocytochemical studies have been prominent in advancing our understanding of mineralized tissue modeling and remodeling. The present review on the application of postembedding, colloidal-gold immunocytochemistry to mineralized tissues focuses on the advantages of this approach and relates them to conceptual, theoretical, and experimental data currently available discussing matrix-mineral interactions and extracellular matrix formation and turnover in these tissues. More specifically, data are summarized regarding the distribution and role of noncollagenous proteins in different mineralized tissues, particularly in the context of how they interface with mineral, and how this relationship might be affected by the various tissue-processing steps and immunocytochemical strategies commonly implemented to examine the distribution and function of tissue proteins. Furthermore, a technical discussion is presented that outlines several different possibilities for epitope exposure in mineralized tissues during preparation of thin sections for transmission electron microscopy. Cell biological concepts of protein secretion by cells of the mineralized tissues, and subsequent extracellular matrix assembly and organization, are illustrated by examples of high-resolution, colloidal-gold immunolabeling for osteopontin, bone sialoprotein, and osteocalcin in the collagen-based mineralized tissues and for enamel protein (amelogenin) in enamel. © 1995 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070310105
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  • 7
    Electronic Resource
    Electronic Resource
    Chemical modification of titanium surfaces for covalent attachment of biological molecules (1998)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 40 (1998), S. 324-335 
    Details
    ISSN: 0021-9304
    Keywords: titanium ; bioactive coating ; immobilization ; silanization ; covalent attachment ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The surface of implantable biomaterials is in direct contact with the host tissue and plays a critical role in determining biocompatibility. In order to improve the integration of implants, it is desirable to control interfacial reactions such that nonspecific adsorption of proteins is minimized and tissue-healing phenomena can be controlled. In this regard, our goal has been to develop a method to functionalize oxidized titanium surfaces by the covalent immobilization of bioactive organic molecules. Titanium first was chemically treated with a mixture of sulfuric acid and hydrogen peroxide to eliminate surface contaminants and to produce a consistent and reproducible titanium oxide surface layer. An intermediary aminoalkylsilane spacer molecule was then covalently linked to the oxide layer, followed by the covalent binding of either alkaline phosphatase or albumin to the free terminal NH2 groups using glutaraldehyde as a coupling agent. Surface analyses following coating procedures consisted of X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Enzymatic activity of coupled alkaline phosphatase was assayed colorimetrically, and surface coverage by bound albumin was evaluated by SEM visualization of colloidal gold immunolabeling. Our results indicate that the linkage of the aminoalkylsilane to the oxidized surface is stable and that bound proteins such alkaline phosphatase and albumin retain their enzymatic activity and antigenicity, respectively. The density of immunolabeling for albumin suggests that the binding and surface coverage obtained is in excess of what would be expected for inducing biological activity. In conclusion, this method offers the possibility of covalently linking selected molecules with known biological activity to oxidized titanium surfaces in order to guide and promote the tissue healing that occurs during implant integration in bone and soft tissues. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 40, 324-335, 1998
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Use of backscattered electron imaging on developed radioautographic emulsions: Application to viewing rat incisor enamel maturation pattern following 45calcium injection (1987)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 5 (1987), S. 357-365 
    Details
    ISSN: 0741-0581
    Keywords: BEI ; Calcium ; Enamel ; Radioautography ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Backscattered electron imaging (BEI) can be used to obtain compositional contrast in biological structures because it detects differences in concentration of elements with different atomic number. Rat incisor enamel shows a banded pattern in the maturation zone when radioautography is used to reveal the location of injected 45Ca at the enamel surface. The bands of developed silver grains in the photographic emulsion that coats the enamel surface are ideal for atomic number contrast. The purpose of this study was to use BEI to analyze the radioautographic pattern with SEM resolution. One-month-old rats were injected with 45Ca and sacrificed at early (1 min, 5 min, 30 min), intermediate (4 h, 8 h), and late (1 day, 4 days) time intervals after injection. Whole incisors were dissected, the enamel organs were removed, and the enamel surface was coated with photographic emulsion and processed for radioautography. These radioautographed teeth were examined with a JEOL JSM-840 SEM equipped with a JEOL backscatter annular-type detector. At the early time intervals, light microscopic examination showed five or six broad black bands running obliquely across the teeth. These were separated by narrow white bands of unlabeled enamel. BEI resolved the presence of a delicate subbanding pattern within each dark band. At the intermediate time intervals, although the incisal bands persisted, only a diffusely blackened apical area was seen by light microscopy. BEI resolved bands in this apical region, but these showed no subbanding pattern. At the late time intervals, both light microscopy and BEI showed no banding, and the enamel was uniformly labeled. The significantly improved resolution obtained with BEI on surface radioautographs has revealed a previously undetected substructure in the 45Ca-labeled banding pattern seen in enamel maturation.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1060050406
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  • 9
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    Local gene transfer to calcified tissue cells using prolonged infusion of a lentiviral vector (2006)
    Springer Nature
    Details
    Publication Date: 2006-07-20
    Print ISSN: 0969-7128
    Electronic ISSN: 1476-5462
    Topics: Biology , Medicine
    Published by Springer Nature
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  • 10
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    Cag-delta (Cag3) protein from the Helicobacter pylori 26695 cag type IV secretion system forms ring-like supramolecular assemblies (2017)
    Oxford University Press
    Details
    Publication Date: 2017-01-08
    Description: Helicobacter pylori is an important cause of gastric pathologies and persistent infection can lead to stomach cancer. Virulent H. pylori strains encode a type IV secretion system responsible for translocation of the oncogenic CagA protein into cells of the gastric mucosa. Gene HP0522 encodes the essential component Cag (Cag3), and we show by gel filtration and cross-linking that purified Cag forms high molecular mass complexes. In contrast, its interaction partner CagT is mostly monomeric, but co-fractionates after gel filtration. Analysis by transmission electron microscopy revealed that purified Cag complexes can self-assemble ring-like structures. Cag-overexpressing Escherichia coli exhibits membrane-associated circular profiles in regions of the cell envelope with intense immunogold labelling with a Cag-specific antiserum. Our results suggest that Cag has the capacity to form macromolecular structures contributing to the assembly of the type IV secretion system.
    Keywords: Pathogens & Pathogenicity
    Print ISSN: 0378-1097
    Electronic ISSN: 1574-6968
    Topics: Biology
    Published by Oxford University Press
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