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  • 1
    Electronic Resource
    Electronic Resource
    Capillaries in the lamina propria of human seminiferous tubules are partly fenestrated (1996)
    Springer
    Cell & tissue research 286 (1996), S. 93-102 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Microvasculature ; Fenestrated capillaries ; Lamina propria ; Testis ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The three capillary parts of the microvasculature of the human testis, namely the arterial side inter-Leydig cell capillaries, the intramural capillaries, and the venous side inter-Leydig cell capillaries, were studied in detail by dual detection of alkaline phosphatase enzyme activity and endothelial marker immunoreactivity, and by means of light- and transmission-electron microscopy. Alkaline phosphatase enzyme activity was seen in intertubular arterioles, capillaries, and venules, and in intramural capillaries of the human testis, whereas the lamina propria of human seminiferous tubules showed no staining. Alkaline phosphatase enzyme activity and the endothelial marker detected by the Qbend 30 antibody co-existed within the endothelial cells of the microvasculature. Electron-microscopically, the endothelial cells of the arterial and venous side inter-Leydig cell capillaries, and of the intertubular capillaries free of Leydig cells were of the continuous type without fenestrations (A-1-α type). The intramural capillaries consisted of non-fenestrated (A-1-α type) and fenestrated sections (A-2-α type). The fenestrations faced the germinal epithelium. Capillaries with a continuous non-fenestrated endothelium contained a large number of transcytotic vesicles and channels. These were numerous in the endothelial cells of the inter-Leydig cell capillaries and the non-fenestrated part of the intramural capillaries. Capillaries partly ran in between the layers of the lamina propria and therefore represented the capillarization of the seminiferous tubules. Thus the multilayered lamina propria probably requires its own capillary supply to allow rapid exchange between the microvasculature and the epithelium of the human seminiferous tubules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050678
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  • 2
    Electronic Resource
    Electronic Resource
    Cellular architecture of the lamina propria of human seminiferous tubules (1990)
    Springer
    Cell & tissue research 262 (1990), S. 253-261 
    Details
    ISSN: 1432-0878
    Keywords: Lamina propria ; Seminiferous tubule ; Myofibroblasts ; Immunoreactivity ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The lamina propria of human seminiferous tubules is composed of 5 to 7 cellular layers separated by laminae of extracellular connective-tissue components. By means of immunocytochemical methods the different nature of the cellular layers could be defined for the first time. Based on the light-microscopic demonstration of both desmin-like and vimentin-like immunoreactivity in the inner 3 to 4 layers of the lamina propria, these cells can be identified as myofibroblasts. The outermost one or two cellular layers, on the contrary, only show a vimentin-like immunoreactivity indicating the pure fibroblastic nature of these cells. Therefore, the outermost cellular layers are suggested to be derivatives of the interstitium. In cases of disturbed spermatogenesis, the lamina propria is frequently considerably thickened by an increase in the extracellular matrix components between the cellular layers. Whereas the ultrastructural localization of laminin-, collagen type-IV- and fibronectin-like immunoreactivity remains unaffected in the thickened lamina propria, the desmin-like immunoreactive cells of the inner layers strongly decrease in number and staining intensity. Most probably, the myofibro-blasts lose their myoid characteristics to participate in the secretion of increased amounts of extracellular matrix components, which in turn presumably block the mediation of the lamina propria between the interstitium and the germinal epithelium. It is still unclear whether the thickened lamina propria provokes the disturbance of spermatogenesis or vice versa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00309880
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  • 3
    Electronic Resource
    Electronic Resource
    On structural patterns of the lamina propria of human seminiferous tubules (1973)
    Springer
    Cell & tissue research 141 (1973), S. 413-425 
    Details
    ISSN: 1432-0878
    Keywords: Seminiferous tubules, human ; Lamina propria ; Contractile cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the lamina propria of human seminiferous tubules was analyzed in normal specimens and compared to biopsies showing great thickenning of this area in light microscopy. The contractile cells are stellate in shape, the intercellular gaps between their branchings being less than 150 Å. The cytoplasmic features of these cells are similar to those described by Ross and Long (1966) and do not differ significantly in the pathological cases examined. The intercellular components, namely collagen fibers, microfibrils and an incomplete basement membrane-like coating of the contractile cells, are strikingly increased in the thickenned lamina propria, although the number of layers making up this structure needs not be increased. Occasionally, the intercellular space is occupied by only one of these materials. The distribution of collagen permits identification of two main patterns in the thickenned lamina propria: a) one where the basement membrane of the seminiferous epithelium is separated from the first layer of contractile cells by a wide collagen zone, and b) another case where the layer displaying greater thickness because of increased collagen deposition is located further away from the germinal epithelium. The functional activity of the contractile cells, the physiological implication of structural alterations of the lamina propria and the necessity to correlate these observations to andrological findings, are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307414
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