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  • 11
    ISSN: 1573-6865
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The gingiva of rat molars was studied at the light microscope level using glutaraldehyde as fixative, Cuprolinic Blue for visualizing polyanionic glycosaminoglycans and the autometallographic technique for enhancing the copper signal of the cationic dye. The polyanions were located inside the epithelial cells in the junctional epithelium, whereas a network located along either the plasma membrane or the intercellular spaces, or both, of the gingival oral epithelium and sulcular oral epithelium was evident with autometallography. In these cases, positive staining was limited to the basal and spinous layers, the granular and keratinized layers being unstained. With the transmission electron microscope, electron-dense aggregates were seen in the gingival lamina propria, in the basement membrane and along the plasma membrane of the keratinocytes of the basal and spinous layers of the gingival and sulcular oral epithelia. In the junctional epithelium, Cuprolinic Blue-positive granules, 25 nm in diameter, were seen in the cytoplasm. Together with some vesicles containing electron-dense material, they may account for the staining process noted after autometallography. When the ultra-thin sections were digested with bovine testicular hyaluronidase, the staining was abolished. This indicates that glycosaminoglycans were primarily responsible for the staining pattern visualized with these methods. In the junctional epithelium, the cytosolic location of the 25 nm granules reflects either transcellular transfer between the plasma membrane and the nucleus or accumulation of glycosaminoglycans in this group of keratinocytes. The glycoconjugates located inside vesicles or vacuoles are related to endocytosis and lysosomal degradation. Interstitial glycosaminoglycans seen in the two types of oral epithelium may play a role in the diffusion of water and nutriments.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 216 (1986), S. 181-190 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The ultrastructural distribution of complex carbohydrates in an early formation stage of rat incisor enamel was investigated by staining with the periodic acid-thiocarbohydrazide-silver proteinate reaction (PA-TCH-SP) for vicinal glycol-containing glycoconjugates, the phosphotungstic acid-chromic acid mixture (PTA) for glycoproteins, and the cationic dyes alcian blue or bismuth nitrate for sulfated glycoconjugates. In order to remove selectively sulfated complex carbohydrates, half of the serial sections obtained were digested with a bovine testicular hyaluronidase prior to staining.Far fewer electron-dense deposits were observed with the PA-TCH-SP method on hyaluronidase-treated sections, especially those subsequently treated for 48 hours with TCH. On the other hand, the minimal staining obtained with PTA was much more intense on sections treated with hyaluronidase where linear fiberlike structures were observed. With cationic dyes, staining of dotlike alignment structures and ground substance was obtained but was completely abolished by hyaluronidase treatment. Cuprolinic blue in a critical electrolyte concentration, ruthenium hexamine trichloride used with aldehyde during fixation, as well as rapid-freezing followed by freeze-substitution validate that this dotlike distribution is not an artefact of processing.The staining results demonstrated that the glycoproteins and sulfated complex carbohydrates in developing rat incisor enamel each display a specific distribution pattern. The glycoproteins were present as fiberlike structures and the sulfated carbohydrates appeared as dotlike formations located close to the surface of the fiberlike structures, and/or in the spaces between them.
    Additional Material: 26 Ill.
    Type of Medium: Electronic Resource
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  • 13
    ISSN: 0003-276X
    Keywords: Macrophage polykaryon ; Osteoclast ; Ceramic biomaterials ; Wound healing ; Bone defects ; Calcitonin ; Tartrate resistant acid phosphatase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Background: The nature of the multinucleated giant cells (MNGC) elicited in contact with implantable biomaterials is still indecisive.Method: In Wistar rats the MNGC recruited after the implantation of hydroxyapatite (HA) particles in standardized skull defects were examined morphologically (at both the light and electron microscope levels), enzymatically (tartrate-resistant acid phosphatase and non-specific esterase), and after a challenge with salmon calcitonin.Results: The MNGC were of great size and contained abundant mitochondria, vacuoles, and vesicles throughout the cytoplasm; they were either tightly apposed to the HA surface or had long and thin processes penetrating the material. When processed for tartrate-resistant acid phosphatase, only a few cells were weakly stained. The staining was totally suppressed when samples were pretreated with cyanuric chloride in the MNGC but not in the host osteoclasts. Calcitonin induced the withdrewal of the host osteoclasts from the bone surface while the MNGC remained in contact with the HA material.Conclusion: The MNGC recruited to HA particles did not exhibit the morphologic, enzymatic and functional characteristics of the osteoclasts, and consequently must be regarded as macrophage polykaryons. © 1995 Wiley-Liss, Inc.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 14
    ISSN: 1432-0878
    Keywords: Basement membrane ; Lipids ; Ultrastructure ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Developing rat incisors were treated with malachite green-aldehyde fixative solution (MGA), which retains and stains lipids. We observed positive staining occurring as dots in the basement membrane. Most of these dots (2–3.5 nm in diameter) were grouped in the lamina densa but some were also present in the lamina lucida and the lamina fibroreticularis. These data provide evidence for the existence of lipids in the dental basement membrane and suggest that they are distributed together with the various groups of proteins so far detected.
    Type of Medium: Electronic Resource
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  • 15
    ISSN: 1432-0878
    Keywords: Tunicamycin ; Glycogen ; Odontoblasts ; Enamel organ ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Repeated injection of rats with tunicamycin over two days induced a 1- to 5-fold increase in glycogen. This accumulation occurred in the stratum intermedium of the enamel organ and in young secretory odontoblasts. In rats injected over 3 days, the number of glycogen particles was at least 10 times larger than in control rats, and large glycogen accumulations were observed in the cytosol of these two groups of cells. These results were obtained by staining with periodic acid-thiocarbohydrazide and silver proteinate, a specific method for the detection of glycoconjugates containing vic-glycol groups. The existence of a relationship between these local cytosolic accumulations of glycogen and the developmental stage of certain groups of cells was shown by the changes that occurred in glycogen distribution. The present results suggest that the stratum intermedium supplies energy for precursor transport.
    Type of Medium: Electronic Resource
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