Histology and histopathology Vol. 6, nº 3 (1991)
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- PublicationOpen AccessElectron microscopic study of the effects of endotoxin on the cells of the hepatic sinusoid in normal and BCG sensitized mice(Murcia : F. Hernández, 1991) McCuskey, Patricia A.; McCuskey, Robert S.Electron microscopic studies were conducted to access ultrastructural alterations in Kupffer cells and other cells lining the hepatic sinusoids at the peak of mediator release two hours after challenge with low doses of endotoxin under various conditions including reticuloendothelial system (RES) expansion and activation with BCG. BCG is known to sensitize animals to endotoxin rendering normally innocuous, low doses of endotoxin lethal. Low non-lethal doses (5 pg) of endotoxin activated Kupffer cells as well as caused isolated foci of cellular injury. However, animals which were treated with BCG had a highly activated and expanded RES system as evidenced by enlarged Kupffer cells with many extended cellular processes. Granulomas were prevalent and many reactive cells were present. After two hours marked cellular injury occurred to sinusoid lining and parenchymal cells when BCG treated animals were challenged with these same low doses of endotoxin. Cellular debris, fibrin, and platelets were observed in sinusoids often associated with Kupffer cells. These results suggest that the functional state of Kupffer cells is an important determinant in the host response to endotoxin. While there appears to be an effective clearance of endotoxin; the release of mediators by the highly activated Kupffer cells can be toxic causing hepatocellular injury.
- PublicationOpen AccessCircadian and seasonal variations in pineal gland intercellular canaliculi in the white rat(Murcia : F. Hernández, 1991) Martínez Soriano, F.; Cimas García, C.; Ruíz Torner, A.Seventy Wistar rats are used to study the changes in pineal intercellular canaliculi over a 21-hour period and for two different photoperiods (pre-autumn, first week of September, and winter, first week of February). The study considers these changes at pineal body, cortical and medullar level separately, and compares the values obtained. The results show variations in canalicular surface at different point times (10:00, 14:00,18:00) and for both photoperiods. The variations are found to favour the cortical layer, and are also observed between nocturna1 and diurnal hours. Canalicular surface to greater during the diurnal hours of both photoperiods. Interesting histological findings are described that suggest an important function of the intercellular canaliculi in pineal gland metabolic exchange.
- PublicationOpen AccessPathological changes in dendrites of substantia nigra neurons in Parkinson's disease: a Golgi study(Murcia : F. Hernández, 1991) Patt, Stephan; Gertz, Hermann-Josef; Gerhard, Lieselotte; Cervós-Navarro, J.Neurons of the substantia nigra show severe morphological changes in Parkinson's disease. Pathological alterations of cell bodies have been described, whereas those of neuronal processes have hardly been investigated. Golgi impregnation has been the chosen method for demonstrating neuronal processes and dendritic and somatic spines. We therefore used the Golgi-Braitenberg method to qualitatively and semi-quantitatively study the substantia nigra of eight patients with Parkinson's disease compared with eight control cases. Golgi impregnation of substantia nigra neurons was good in al1 control cases. In full agreement with the analysis of Braak and Braak (1986) three neuronal types within the substantia nigra were found. In cases of Parkinson's disease, severe pathological changes such as decrease of dendritic length, loss of dendritic spines and severa1 types of dendritic varicosities were found only in the melanin-containing pars compacta neurons. Pars reticulata nerve cells were intact. These findings support the predominant role played by the dopaminergic efferent pathway in the degenerative process. The afferent pathway was not affected. This suggests that the substantia nigra lesion is primary in Parkinson's disease. Loss of neurons found in H & E sections corresponded to a lesser amount of impregnated pars compacta neurons in cases with Parkinson's disease when compared to controls. Evidences exist that the duration of the disease may be related to the extent of pathologically altered Golgi-impregnated pars compacta cells. The amount of Lewy bodies in H & E sections corresponded to the quantity of round varicosities in impregnated pars compacta neurons. These round dendritic varicosities were considered to be Lewy body inclusions. They seem to have no influence on the dendritic spine density and morphology in most cases.
- PublicationOpen AccessMyofibroblasts and myoepithelial cells in the chicken Harderian gland(Murcia : F. Hernández, 1991) Cacho, Emilio del; Gallego, Margarita; Felices, Carlos; Bascuas, J.A.An electron microscopic study of the myoepithelial cells in the chicken Harderian gland provides evidence that these cells can be transformed into myofibroblasts. After the application of a Brucella ovis suspension in sterile saline onto the eyeball, every 5 minutes for half an hour, myoepithelial cells gradually develop over a 90-minute period the characteristic features of myofibroblasts: bundles of intracytoplasmic microfilament; abundant rough endoplasmic reticulum; prominent Golgi complex; and surface membrane differentiations, that provide attachment to neighbouring epithelial cells. No typical desmosomes are observed. Besides, the intercellular space between epithelial cells and myofibroblasts increases and the basement membrane adjacent to myofibroblasts disappears. Hypoxia is hypothesized to be involved in the transformation of myoepithelial cells into myofibroblasts.
- PublicationOpen AccessHelicobacter pylori in Barrett's esophagus(Murcia : F. Hernández, 1991) Ferreres, Joan-Carles; Fernández, Fidel; Rodríguez Vives, Agustín; González-Rodilla, Irene; Ursúa, Inmaculada; Ramos, Rafael; Val-Bernal, José FernandoBarrett's esophagus is an anatomicoclinical state in which, due to the prolonged action of gastroesophageal reflux, the squamous epithelium is replaced by columnar epithelium. Helicobacter pylori has been implicated in the pathogenesis of various gastrointestinal disorders and has occasionally been observed in Barrett's esophagus. The aim of this study is to determine the incidence of H. pylori in Barrett's esophagus and try to establish its role in the pathogenesis of this disorder. H. pylori was observed in 31 biopsies (44.3%) of the 70 studied, mainly when the epithelium is of the gastric atrophic-fundic type (p < 0.01). Its presence shows no relation to the degree of inflammatory activity and does not seem, therefore, to play an important role in the pathogenesis of the lesion.