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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 70 (1986), S. 262-268 
    ISSN: 1432-0533
    Keywords: Meningioma ; Psammoma body ; Fine structure ; Matrix vesicle ; Matrix giant body
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Psammoma bodies in meningocytic whorls were investigated by electron microscopy. In some whorls, connective tissue fibers were seen and membrane-bound vesicles were contiguous to degenerated cells. Some small vesicles, 0.1 to 0.5 μm in diameter, were outlined by plasma membrane (matrix vesicles), other larger ones, about 1 to several μm in diameter, were invested by a thick wall (matrix giant bodies). Mineralized deposits were frequent in these vesicles and occasionally large masses of mineralized connective tissue fibers (psammoma bodies) were seen. Analysis of the material in the mineralized vesicles and fibers, using an energy dispersive X-ray microanalyzer, showed that both calcium and phosphorous were evident and hydroxyapatite was substantiated using an X-ray differactometer. Psammoma body formation in the meningocytic whorls may represent degeneration in some whorls of the central cells which contain connective tissue fibers, producing cell debris such as membrane invested vesicles. Subsequently, calcification occurs in these vesicles, and the mineralization process extends to neighboring connective tissue fibers. The calcified mass forms a psammoma body.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 76 (1988), S. 458-464 
    ISSN: 1432-0533
    Keywords: Immunohistochemistry ; Folliculo-stellate cells ; Pituitary adenomas ; Intermediate filaments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Folliculo-stellate (FS) cells were studied in 102 human pituitary adenomas by immunohistochemical techniques using antibodies to S-100 protein and intermediate filaments protein. In most pituitary adenomas there were few S-100-positive cells, in contrast, numerous FS cells were found in four of the 54 cases of non-functioning adenomas. Among glial fibrillary acidic protein (GFAP), keratin and vimentin, FS cells showed greatest affinity to vimentin. Stains for desmin or neurofilaments were always negative. Counterstains with GFAP and keratin could demonstrate a small number of double-labelled cells, but mainly disclosed two types of FS cells positive for either GFAP or keratin. Accordingly, FS cells were grossly subdivided into two types: GFAP-positive cells which might be neuroectodermal or glial in origin and keratin-positive cells which might be oral ectodermal or derive from the Rathke's pouch.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 67 (1985), S. 219-225 
    ISSN: 1432-0533
    Keywords: Inner membrane ; Chronic subdural hematoma ; Dural border cell ; Arachnoid cell ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electron-microscopic findings of inner membranes of chronic subdural hematomas showed multilayered tiers of flattened cells. The basis characteristics of these cells were similar to dural border cells in the human dura-arachnoid interface layer. The cells covering the hematoma surface had indented nuclei with a prominent nucleolus and were abundant in enlarged rough ER, glycogen granules, lipid droplets, and caveolae. The cells in the intermediate layer had thin cytoplasmic extensions containing tonofilaments, which were oriented almost parallel to the long axis of inner membranes. The cells facing the arachnoid surface sometimes showed disintegration of cellular organelles and dissolution of nuclear chromatin. Between these cells and the tiers was an increased amount of extracellular substance, such as collagen fibrils, clastins, and finely granular material, which were often intermingled with blood pigments or fibrins, especially toward the arachnoid surface. In two of the ten cases studied, there was a syncytial mass of arachnoid cells which reinforced the arachnoid surface of inner membranes. Conceivably, a primary extravasation of blood within the dura-arachnoid interface layer may cleave a few tiers of dural border cells, which envelope the inner surface of the hematoma, proliferate, and later on form inner membranes.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 80 (1990), S. 255-259 
    ISSN: 1432-0533
    Keywords: Meningioma ; Phospholipid ; Psammoma ; Ultrastructure ; Chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Phospholipids in meningiomas were studied by light and electron microscopy, and by high-performance liquid chromatography. They were microscopically demonstrated in six of the ten cases by Sudan III staining after the fixation with potassium dichromate. However, the conventional ultrastructural fixation with glutaraldehyde and osmium tetroxide failed to confirm phospholipids, as most of them were dissolved during dehydration. In contrast, the specimens pretreated with tannic acid before osmication ultrastructurally retained phospholipids which were represented by multilamellar bodies or ribbon-like rings. Both were found in 23 of the 30 cases within the cytoplasm, among the plasma membranes and in the extracellular matrices. The outermost lamella or ribbon showed a direct continuity from the neighbouring plasma membranes of the cytoplasm or the mitochondria. The multilamellar bodies showed an overall distribution, while the ribbon-like rings were predominantly distributed around the psammoma bodies. Precipitation of hydroxyapatite crystals within the ribbon-like rings resulted in matrix minerals of psammoma bodies. Chromatographical analyses of meningiomas disclosed phospholipids including phosphatidyl ethanolamine, phosphatidyl choline, phosphatidyl serine, sphingomyelin and phosphatidyl inositol in that order. Psammomatous meningiomas contained a higher percentage of phosphatidyl serine than non-psammomatous tumors. Ultrastructural study of synthetic phospholipids adequately treated with tannic acid showed that the multilamellar bodies were similar to phosphatidyl choline, while the ribbon-like rings were similar to phosphatidyl serine. The role of phospholipids in meningiomas is discussed.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 66 (1985), S. 223-232 
    ISSN: 1432-0533
    Keywords: Epinephrine ; Meningothel ; Rosette ; Desmosome ; Tonofilament
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A previously unrecognized type of rosette consisting of meningothelial cells is reported. Meningothelial clusters with a formation of numerous rosettes were incidentally observed in the canine subarachnoid space after single subarachnoid, injection of 0.2 mg/kg of epinephrine. Light microscopy revealed that the cell clusters with distinct rosettes occurred in the extensive cords and nests, surrounding the small subarachnoid arteries or adhering to the arachnoid epithelium. There were scattered mast cells adjacent to the cell clusters. Electron microscopy revealed that the resettes usually consisted of four to 12 tightly packed cells which were arranged like spokes and contained concentrations of tonofilaments. The rosette cells were knitted together by numerous junctional devices, such as desmosomes and desmosome-like junctions as well as a small number of interdigitations at the lateral surfaces toward the central core. The latter measured approximately 0.77–12.72 μm in long diameter, containing electrondense, coarsely granular material. Both intracytoplasmic and extracellular inclusions with projecting microvilli were reminiscent of hyaline inclusions in certain meningiomas.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 71 (1986), S. 100-105 
    ISSN: 1432-0533
    Keywords: Ependymona ; Fine structure ; Abnormal cilia ; Giant cilia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Abnormal cilia were frequently exposed in a malignant ependymoma of the cerebellar vermis by an electron microscope study. Among these erratic cilia, compound cilia, huge axoneme with bizarre shapes, were repeatedly observed. These giant cilia commonly had random orientation of many microtubular doublets as well as complicated cavities in their granular ciliary matrix. Additionally, abnormal cilia of normal-sized axoneme showed diversified arrangement of peripheral doublets and central singlets. The formation process of these abnormal cilia is discussed.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 71 (1986), S. 19-25 
    ISSN: 1432-0533
    Keywords: Arachnoid villi ; Psammoma body ; Matrix granule ; Matrix vesicle ; Matrix mineral
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fine structure of the human arachnoid villi was studied to clarify the origin of psammoma bodies. Within the villous surface layer, collagen fibrils and fine granular material clustered forming microcores of variable caliber measuring up to 10 μm. An early stage of psammoma body formation was seen more frequently in these villous microcores than in the meningocytic whorls. The villous microcores contained a large number of membrane-free matrix granules as well as a small number of membranebound matrix vesicles and matrix minerals. The matrix granules were irregularly oval structures with electronlucent halo, measuring 0.05–0.70 μm in diameter. Hydroxyapatite crystals were frequently precipitated within and around the matrix granules which aggregated with calcifying matrix vesicles and matrix minerals. Numerous calcifying matrix granules were present within and around enlarging psammoma bodies. The matrix granules may serve as the principal calcification nidi of psammoma bodies in the human arachnoid villi. The possible mechanisms of matrix granule biogenesis are extrusion of preformed arachnoid cell structures or secretion of fine granular material with its extracellular assemblage.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Acta neurochirurgica 96 (1989), S. 149-153 
    ISSN: 0942-0940
    Keywords: Cranioplasty ; hydroxylapatite ceramics ; apatite plate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The author has designed new cranioplastic materials to reconstruct a skull defect of moderate size in both the convexity and the suboccipital region. A domed and elliptic plate measuring 50×75 mm in diameter, 12 mm in the maximum height and 5 mm in thickness was made from hydroxylapatite ceramics. The latter comprise Ca10(PO4)6(OH)2 as mammalian bone minerals and are characterized by an excellent biocompatibility and biostability resulting in bony fusion. Hydroxylapatite ceramic plates can be easily trimmed during surgery to closely fit the skull defect. There were no adverse reactions nor resorption of the implants.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0942-0940
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Acta neurochirurgica 142 (2000), S. 829-831 
    ISSN: 0942-0940
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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