Ictericias: histología

La descripción histológica detallada del hígado resultaría demasiado extensa para los fines del presente trabajo. Por tal motivo, se destacarán solamente los aspectos más importantes vinculados al tema tratado.Facultad de Ciencias Médica

Histología del páncreas exocrino

El páncreas está formado por dos componentes secretorios: el tejido insular o endocrino (islotes de Langerhans) y el tejido insular o exocrino. Solamente nos referiremos a este último. La actualización de la histología del páncreas endocrino será objeto de otro trabajo. En páncreas exocrino se presenta como una glándula túbulo-acinosa compuesta, esto es, constituida por numerosas porciones secretoras o adonómeras en forma de túbulos y ácinos, que desembocan en conductos excretores muy ramificados. La glándula está subdividida por delicados tabiques de tejido conectivo en pequeños lobulillos. Este tejido conectivo, que se continúa hasta contactar con las adenómeras, contiene vasos sanguíneos, linfáticos y nervios.Facultad de Ciencias Médica

Histología del páncreas exocrino

El páncreas está formado por dos componentes secretorios: el tejido insular o endocrino (islotes de Langerhans) y el tejido insular o exocrino. Solamente nos referiremos a este último. La actualización de la histología del páncreas endocrino será objeto de otro trabajo. En páncreas exocrino se presenta como una glándula túbulo-acinosa compuesta, esto es, constituida por numerosas porciones secretoras o adonómeras en forma de túbulos y ácinos, que desembocan en conductos excretores muy ramificados. La glándula está subdividida por delicados tabiques de tejido conectivo en pequeños lobulillos. Este tejido conectivo, que se continúa hasta contactar con las adenómeras, contiene vasos sanguíneos, linfáticos y nervios.Facultad de Ciencias Médica

Ictericias: histología

La descripción histológica detallada del hígado resultaría demasiado extensa para los fines del presente trabajo. Por tal motivo, se destacarán solamente los aspectos más importantes vinculados al tema tratado.Facultad de Ciencias Médica

On the presence of conspicuous electron dense bodies in the pinealocytes of the pig

The pinealocytes of the pig contain a large number of aldehydefuchsin positive granules. In order to determine their nature an ultrastructural study was carried out. Numerous bodies having a maximal diameter of about 1,600 nm were found. These elements showed a great variety of internal structure, ranging from a “homogeneous” content and amorphous dense aggregates to lamellate bodies. Although only a few of them displayed a positive reaction for acid phosphatase, their morphological appearance strongly suggests that they belong to the lysosomal system.Facultad de Ciencias Médica

Cytological differences in the localization of glucocorticoid receptor-like immunoreactivity in the normal and transplanted pituitary pars intermedia

Glucocorticoid receptor-like immunoreactivity (GCRI) was found in the normal pituitary pars intermedia (PI) when immunohistochemistry was used. Since in previous studies we described two kinds of cells in the denervated (grafted) PI, i.e., "light cells" (overactive cells which do not contain detectable melanocytestimulating hormone) and "dark cells" (hypoactive cells which contain the hormone), it was decided to investigate whether different patterns of distribution of the receptors could be detected in the glared gland when compared with the intact PI. Intact glands showed the receptors located in the nucleus. In transplanted glands, it was observed that light cells showed receptors in both the nuclei and the cytoplasm; on the other hand, dark cells displayed them in the nuclei only, as is the case in all cells of the normal PI. We had previously interpreted dark cells as dopamine-indifferent whereas light cells were considered dopamine-sensitive. The changes in the distribution of GCR after denervation by grafting, which only affected the light cells, support the view of other authors that GCR of the pars intermedia are under the influence of dopamine and reinforce our opinion that dark cells are dopamine-indifferent.Facultad de Ciencias Médica

Ultrastructural study of the coypo (Myocastor coypus) adenohypophysis

Por nuestro conocimiento no existen poblaciones concernientes a la ultraestructura de la adenohipófisis del Coipo. Este estudio tiene por objeto describir la estructura fina de las diferentes poblaciones celulares en la Pars distalis de la hipófisis del coipo adulto normal mediante técnicas convencionales para microscopía electrónica de transmisión: fijación en glutaraldehído post fijación en osmio e inclusión en resinas epoxy. Se emplearan 4 coipos machos y 4 hembras adultos mantenidos bajo condiciones naturales de luz, agua y alimento ad libitum. Se pudieron distinguir 5 tipos de células granuladas y 2 tipos de células no granuladas teniendo en cuenta principalmente la presencia de los gránulos de secreción y sus características. Las presentes observaciones efectuadas por primera vez en la adenohipófisis del coipo abren el camino para ampliar la información con nuevos estudios, especialmente basados en la inmunohistoquímica.The fine structure of the Myocastor coypus (coypu) adenohypophysis was studied by conventional techniques by transmission electron microscopy The material was fixed in glutaraldehyde post-fixed in osmium tetroxide and embedded in epoxy resins Five types of granulated cells as well as two types of agranular cells could be identified taking into account mainly the present and characteristics of their secretory granules When these cells were compared to those previously described in other mammals such as humans rats and mice somatotrophic and gonadotrophic cells were fairly recognized However the possibility of detecting other cell types without the use of immunocytochemical methods was less reliable to the species studied the presence of highly developed population of follicular agranular cell must be emphasized The present observations, made for the first time in the coypo adenohypophysis would open the way by further studies on the field especially those based in immunohistochemistry.Facultad de Ciencias Veterinaria

Variations in the Golgi complex of mouse somatotrops at different times in a 24-hour period

El aparato de Golgi de las celulas somatotropas de la pars distalis de la hipofisis del raton, presenta importantes diferencias ultraestructurales en distintos momentos de un periodo de 24 horas. Es pequeno a mediodia y marcadamente hipertrofico a mediodia y 6 de la tarde.Facultad de Ciencias Médica

Ultrastructural study of somatotroph cells from mice bearing a fast growing transplanted hepatoma, in different periods of the tumor development

The presence of a transplanted, fast-growing hepatoma (SS1-K) produces conspicuous ultrastructural changes in pituitary STH cells of C3H-S male mice. These changes are suggestive of an increased secretion of growth hormone only during the first stages of the tumor development. The hepatoma influence does not seem to be clearly related to the illumination regimen or time of killing.Facultad de Ciencias Médica

Effect of "fasting" and different concentrations of glucose on alpha-linolenic acid metabolism in HTC cells: correlation with the ultrastructural study

HTC cells are able to convert α-linolenic acid into higher homologs by desaturating and elongating reactions. When the cells were cultured in a Krebs Ringer bicarbonate solution (“fasted cells”) a decrease in both biosynthetic reactions took place. “Refeeding” the cells with Swim's 77 medium without glucose enhanced the biosynthesis of polyunsaturated fatty acids from α-linolenic acid family, but when glucose was added to the medium, α-linolenic acid was preferably elongated rather than converted into eicose-pentaenoic acid. The ultrastructural study revealed HTC cells with a simple cytoplasmic organization, showing little evidence of their origin from hepatocytes. The cells cultured in a complete medium appeared well preserved and were similar to those “fasted” for 12 hours and “refed” for another 12 hours using Swim's 77 medium without serum. The amount of glucose in the medium plays a role in preserving the cell structure. This effect does not occur if glucose is added in the absence of aminoacids and vitamins.Facultad de Ciencias Médica