Histology and histopathology Vol. 4, nº 3 (1989)

Ir a Estadísticas

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    Retinal 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.
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    Liver-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.
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    Ultrastructure 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.
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    Surface morphology and ultrastructure of normal and cyclic hematopoietic canine bone marrow in long-term liquid cultures
    (Murcia : F. Hernández, 1989) Al-Lebban, Z.S.; Lange, R.D.; Jones, J.B.; Lothrop, Jr.
    Long-term liquid cultures of normal and cyclic hematopoietic (CH) dog bone marrow produce committed granulocyte-macrophage progenitor cells (CFU-GM) and differentiated granulocytes for severa1 weeks. Analysis of in situ fixed cultures or of cells harvested from the culture supernatants revealed that the cells had ultrastructure and surface morphology characteristic of immature and mature rnyeloid cells. The surface rnorphologies of adherent cells from both normal and CH dogs were similar. The characteristic abnormalities previously reported in neutrophils obtained from CH dogs were not observed in neutrophils obtained from long-term marrow cultures of CH dogs. These results indicate that the cellular abnormalities in the neutrophils of CH dogs may be secondary manifestations of the disease and are not inherent to the pathogenesis of the hematopoietic cells.
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    Ulmtrastructuroef the chronically vagotomised atrial myocardiu m in t he mon key (Macaca fascicularis)
    (Murcia : F. Hernández, 1989) Wong, W. C.; Yick, T. Y.; Ling, E. A.
    The ultrastructure of the atrial myocardium in the monkey (Macaca fascicularis) was studied after bilateral cervical vagotomy and survival times of 100,175 and 367 days. Changes were observed in the nucleus and the cytoplasm of the myocyte. Sequestered within the nuclei of the affected myocytes were cytoplasmic organelles and inclusions. In the late stages, there was a tendency towards condensation and margination of the heterochromatin. Changes in the cytoplasm included increased glycogen, mitochondrial degeneration and myofibrillar disorganisation and degeneration. There was increased collagen and mononuclear cell infiltration in the extracellular space in the later stages. This study has shown that the long term structural integrity of the atrial myocyte depends on an intact vaga1 innervation. The survival of the monkey after chronic bilateral vagotomy suggests that this nonhuman primate is a suitable model for functional studies of the parasympathetically denervated heart.