Histology and histopathology Vol. 4, nº 3 (1989)
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- PublicationOpen AccessRegional adaptation of Müller cells in the chick retina. A Golgi and electron microscopical study(Murcia : F. Hernández, 1989) Prada, F. A.; Espinar, A.; Chmielewski, C. E.; Dorado, M. E.; Genís-Gálvez, J. M.We report the morphological differences of Müller cells in relation to their topography, using the Golgi method. Müller cells in the central retina are long and slender, with numerous inner prolongations. In the peripheral retina, the morphology of the Müller cells adapts to the reduced thickness of the retina1 layers. In this zone, they are short and have thick inner prolongations which end in a large foot in the internal limiting membrane. In the optic disc margin, Müller cells have a particular morphology characterized by thick, arched prolongations that in general form a glial network between the retina and optic nerve. The ultrastructure of these cells is also described. The results are discussed with respect to the nature of Müller cells.
- PublicationOpen AccessRetinal pigment epithelial fine structure in the bobtail goanna (Tiliqua rugosa)(Murcia : F. Hernández, 1989) Braekevelt, Charlie R.The retinal pigment'epithelium (RPE), the choriocapillaris and Bruch's membrane (complexus basalis) have been studied by light and electron microscopy in the bobtail goanna (Tiliqua rugosa) an Australian diurna1 lizard. The RPE consists of a single layer of cuboidal cells which display very deep and tortuous basal (choroidal) infoldings as well as numerous apical (vitreal) processes which interdigitate with the photoreceptor cells. The lateral cell borders are relatively smooth and joined by basally located tight junctions. Internally smooth endoplasmic reticulum is abundant while rough endoplasmic reticulum is not. The RPE cell nucleus is large and vesicular and basally located in the light-adapted state. Polysomes, mitochondria and myeloid bodies are present and widely distributed. Melanosomes are plentiful in the apical region of the epithelial cells in light-adaptation. Bruch's membrane is pentalaminate with the basal lamina of the choriocapillaris being exceptionally thick. The choriocapillaris is a single layer of large-caliber capillaries with thin but only moderately fenestrated endothelium. Numerous dense granules are always present within these endothelial cells.
- PublicationOpen AccessLiver-cell adenoma in an epileptic man on barbiturates(Murcia : F. Hernández, 1989) Jaime Vázquez, J. Jaime; Marigil, Miguel A.The case of a 19-year-old epileptic man with a solitary hepatic adenoma is described. The tumor was 9 x 8.5 x 6.5 cm in size and microscopically consisted of cells similar in appearance to non-neoplastic hepatocytes, arranged in cords with slit-like sinusoids interposed. Bile ducts and portal tracts were conspicuously absent. Our patient was on antiepileptic drugs, among them phenobarbital which experimentally produces liver cell tumors in mice and rats.
- PublicationOpen AccessRetinal pigment epithelial fine structure in the bobtail goanna (Tiliqua rugosa)(Murcia : F. Hernández, 1989) Braekevelt, Charlie R.The retinal pigment'epithelium (RPE), the choriocapillaris and Bruch's membrane (complexus basalis) have been studied by light and electron microscopy in the bobtail goanna (Tiliqua rugosa) an Australian diurna1 lizard. The RPE consists of a single layer of cuboidal cells which display very deep and tortuous basal (choroidal) infoldings as well as numerous apical (vitreal) processes which interdigitate with the photoreceptor cells. The lateral cell borders are relatively smooth and joined by basally located tight junctions. Internally smooth endoplasmic reticulum is abundant while rough endoplasmic reticulum is not. The RPE cell nucleus is large and vesicular and basally located in the light-adapted state. Polysomes, mitochondria and myeloid bodies are present and widely distributed. Melanosomes are plentiful in the apical region of the epithelial cells in light-adaptation. Bruch's membrane is pentalaminate with the basal lamina of the choriocapillaris being exceptionally thick. The choriocapillaris is a single layer of large-caliber capillaries with thin but only moderately fenestrated endothelium. Numerous dense granules are always present within these endothelial cells.
- PublicationOpen AccessUltrastructure of atrial and ventricular myocytes of newborn rats: evidence for the existence of specific atrial granule-like organelles in the ventricle(Murcia : F. Hernández, 1989) Venance, Shannon L.; Pang, Stephen C.The present study examined the ultrastructure of atrial and ventricular myocytes from the heart of newborn rats. It was found that, despite former reports stating that ventricular myocytes in adults do not contain cytoplasmic granules, specific atrial granule-like organelles are present in the ventricles of rats at birth. The presence of these granules together with the relatively underdeveloped contractile apparatus and extensive Golgi complex suggests that the ventricular, like the atrial, myocytes may have an endocrine function before or at birth. Further study is required to determine whether these ventricular cytoplasmic granules contain the same atrial natriuretic peptide species known to be present in the atrial specific granules.