Histology and histopathology Vol. 2, nº 1 (1987)

Ir a Estadísticas

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    Studies on intra-arterial cushions. IV. Perivascular nerve plexuses of ramifying arteries with intraluminal cushions at the branching points
    (Murcia : F. Hernández, 1987) Böck, P.
    Periarterial nerve plexuses were studied at branching points of arteries with intraluminal cushions. Serial sections were prepared from mouse kidney, pancreas and tongue, and studied by means of catecholamine fluorescence and staining for acetylcholinesterase. The periarterial nerve plexuses did not show any peculiarities at the branching points. The intraluminal cushions, as well as the tunica media of both the parent trunk and the collateral branches, were found to be free of vegetative nerves. It is concluded that the shape of intraarterial cushions is passively altered, following the alterations of vascular geometry, and not in response to direct nervous stimulation.
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    The response of subpleural pulmonary capillary endothelium to hydrothorax in rats
    (Murcia : F. Hernández, 1987) Shumko, John Z.; DeFouw, David .
    The principal focus of this study was to evaluate the hypothesis that increased interstitial fluid pressures served to stimulate de novo vesicle formation in pulmonary capillary endothelium. Direct measurements of interstitial fluid pressures within the alveolar septa pose great technical difficulty. The pleural space and subpleural capillaries are easily accessible, and thus, provide a more feasible model to test this hypothesis. After hydrostatic pressure of pleural space fluid was increased by periodic saline infusions into the pleural cavity, vesicle numerical densities were significantly increased in portions of the subpleural capillary endothelium. Those segments of the endothelium that directly apposed the interstitium of the visceral pleura displayed de novo vesicle formation. The endothelial segments located immediately adjacent to the alveolar epithelium were not affected by the elevated interstitial fluid pressures. In addition to the increased vesiculation, those same segments of the endothelium were characterized by increased attenuation of their cytoplasmic compartments. These conformational changes in the plasmalemma of portions of the subpleural capillary endothelium provide support to the tentative hypothesis, however, whether the increased numbers of vesicles contribute to a potential transendothelial transport system or expand a possible static network of membrane invaginations remains uncertain.
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    Scanning electron microscopy of the aggregation of head mesoderm cells from chick embryos
    (Murcia : F. Hernández, 1987) Chamorro, C.A.; Paz, P. de; Villar, J.M.; Fernandez, M
    Head mesoderm cells from chick embryos at different stages of development were dissociated and cultured on plastic coverslips. In all cultures several cellular aggregates were described by means of scanning electron microscopy. Isolated cells present filopodia and lamellipodia. However, when mesoderm cells make contact with one another the filopodial and lamellipodial activity in the contact cellular edge disappear. Thus, the cells into cellular clusters do not present projections. The clusters were circular and bidimensional in character. The scanning electron microscopic observations showed that it is the type 1 variant of "contact inhibition of locomotion" which occurs. By means of these mechanisms the bidimensional aggregates are formed and cellular overlapping is not present. Since the behaviour of the mesoderm cells "in vitro" in some way could be comparable to their behaviour "in situ", the results here observed are discussed in relation to the conduct of mesoderm cells "in vivo".
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    Muscle fiber types in tetrapods. A comparative histochemical and morphometric study
    (Murcia : F. Hernández, 1987) Burgos Bretones, Juan J.; Razquin Peralta, Blanca.; Aguirre Urizar, José; Rivera Pomar, José M.
    A comparative histochemical and morphometric study in two groups of homologous muscles from different tetrapods (rat, pigeon, lizard and frog) was performed. On the basis of their fiber diameters and oxidative enzyme activities, an initial correlation between fiber types of al1 animals is observed, although in the lizard and frog muscles, another fiber type does exists that could not be demonstrated in higher vertebrates. When more than one histochemical techniques are used for the identification of each tetrapod fiber types, the lack of correlation between them becomes obvious. Thus, different animals groups, each showing a characteristic muscle metabolic pattern, could be distinguished.