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  • 1970-1974  (4)
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 169 (1971), S. 613-625 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In sections of thymus stained with the tannic acid-phosphomolybdic acid-amido black (TPA) technique, the epithelial reticular cells can readily be identified by the well-stained tonofibrils in their cytoplasm. In the cortex, flattened epithelial reticular cells form a continuous layer on the inner surface of the capsule and along the interlobular septa. Within the cortex proper, stellate epithelial reticular cells are widely dispersed as a loose network. In the medulla, two zones, referred to as “outer” and “inner” medulla, are distinguished. The outer medulla, like the cortex, contains epithelial reticular cells, but these are more voluminous, are more richly provided with tonofibrils and form a denser network than in the cortex. In the inner medulla no epithelial reticular cells can be seen but instead connective tissue cells and fibers make up the supporting framework. A layer of flattened epithelial reticular cells demarcates the outer from the inner medulla. This layer of cells also extends along the outer surface of blood capillaries seen in the outer medulla and cortex. Around the larger blood vessels, this layer of epithelial reticular cells is separated from the vessel wall by a connective tissue perivascular space. Hence, the inner medulla is continuous with the perivascular spaces and, like them, is supported by connective tissue. Thus, the epithelial reticular cells constitute the supporting framework of the cortex and outer medulla and separate these regions from the connective tissue of the capsule, interlobular septa, blood vessels and inner medulla.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 130 (1971), S. 251-267 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The fine structure of the Golgi apparatus in rat spermatids at various steps of spermiogenesis was investigated in routinely stained preparations as well as in sections stained with the periodic acid-silver technique for the demonstration of glycoprotein.In steps 1-7 spermatids, a layer of cisternae of endoplasmic reticulum envelops the Golgi apparatus. Between this layer and the stack of Golgi saccules, small coated vesicles (500-600 Å) are associated with smooth-surfaced tubular profiles. These are irregular expansions of the first or outermost Golgi saccule. The next few saccules of the stack are regularly arranged and similar to one another. The last or innermost saccule is thick and produces coated buds, similar to the large coated vesicles (900-1200 Å) which are found nearby. Large smooth vesicles with a dense core, known as proacrosomic vesicles, are also found in this location at steps 1 and 2. These at step 3 fuse into the single acrosomic vesicle, which in turn at step 5 transforms into the head cap (while the dense core of the vesicles becomes the acrosomic granule).Using the PA-silver technique on steps 1-7 spermatids, a gradation of staining is observed in Golgi saccules, with the most intense reaction in the innermost saccule, its coated buds and the large coated vesicles nearby. Intense staining is also noted in the head cap, while staining of lesser intensity is observed in the acrosomic granule.In older spermatids (steps 8-18) the Golgi apparatus gradually loses most of the features just described and appears to consist primarily of stacks of saccules with dilated edges. These are only weakly stained by the PA-silver technique.These observations are interpreted as follows. Material produced in the endo-plasmic reticulum would be transferred by small coated vesicles to the outermost saccule of the Golgi stacks. During saccule migration toward the inner aspect of the stacks, the synthesis of glycoprotein would be completed. The transfer of this glycoprotein via the large coated vesicles would cause the proacrosomic vesicles to grow into the acrosomic vesicle which later would become the head cap.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 140 (1974), S. 27-45 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Osmication in an unbuffered aqueous solution of osmium tetroxide allows the forming face of the Golgi apparatus to be labeled in many cell types. This property was utilized to study the spatial configuration of this organelle by examining stereopairs of the same field taken at 1,000 KV after tilting a thick (1 to 7 μUm) section of - 7° or + 7° from the original (0°) position. When examined in 1 μm thick sections at magnifications ranging from 13,000 to 18,000 times, the osmic acid-impregnated element of the Golgi apparatus of ganglion nerve cells, Leydig cells or Sertoli cells takes the appearance of a single layered polygonal network of tubules. This network can only be seen at electron microscope magnifications and is referred to as the primary network or structure of the forming face of the Golgi apparatus. When 2 to 7 μm thick sections are examined under progressively lower magnifications, the details of the primary structure remain discernible but become less conspicuous. The osmiophilic portion of the Golgi apparatus now extends over large areas of the cytoplasm to form an extensive continuous structure. This structure which is in the range of visibility of the light microscope is referred to as the secondary network or structure of the forming face. In ganglion nerve cells, the secondary structure consists of a perinuclear network showing slender projections reaching the nucleus and wider expansions approaching the cell surface; in the Leydig cells it appears as an ovoid structure located at one pole of the nucleus whereas in Sertoli cells it forms a cylindrical structure located in the main shaft of the cytoplasm and extending from the nucleus towards the lumen of the seminiferous tubule. Thus the forming face of the Golgi apparatus displays a primary structure; the tubular roughly polygonal network, which is similar in the three cell types and a secondary structure which varies from cell to cell.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 129 (1970), S. 177-191 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The chromatoid body of rat spermatocytes and spermatids was studied with routine electron microscopy and the PA-silver method for detection of glycoproteins. The chromatoid body consists of a membrane-free aggregate of electron dense, finely filamentous material, in association with small vesicles. In late pachytene spermatocytes, there may be more than one chromatoid body; its dense component is diffusely reticulated. In young spermatids, there is only one chromatoid body per cell; the dense component is fairly compact, but it encloses less dense areas continuous with the cytoplasm. Within the less dense areas, as well as at the periphery of the dense component, small (400-800 Å) oval or tubular vesicular structures are observed whose contents exhibit a positive reaction for glycoprotein in PA-silver stained sections. When the spermatid nucleus begins to elongate, the chromatoid body takes the form of an arc around the axial filament proximal to the centriolar apparatus. Soon thereafter, the bulk of the chromatoid body condenses into a sphere of very dense filamentous material surrounded by a corona of enlarged glycoprotein-containing vesicles. In the later stages of spermiogenesis, the chromatoid body migrates away from the nucleus and disintegrates by fragmentation. It is noted that the chromatoid body undergoes its major morphological changes, possibly indicative of its active phase, while located in the para-centriolar region, at the time when the nucleus elongates, and the connecting piece and ring of the spermatid are formed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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