Histology and histopathology Vol. 7, nº 2 (1992)
Ir a Estadísticas
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- PublicationOpen AccessEffects of omeprazole on the number of immunoreactive gastrin- and somatostatin-cells in the rat gastric mucosa(Murcia : F. Hernández, 1992) Pawlikowski, M.; Karbownik, M.; Lewinski, A.; Pisarek, Hanna; Wajs, E.; Szkudlinski, M.The effects of omeprazole - an inhibitor of gastric acid secretion - on gastrin (G)- and somatostatin (D)-cell density in the gastric antral mucosa epithelium in rats were examined, following a 5-day treatment. It was found that omeprazole increased the density of G-cells, whereas it decreased the density of D-cells. That effect was probably independent of hypergastrinaemia, since it could not be blocked by a simultaneous treatment with proglumide - a gastrin receptor blocker. It is concluded that the observed phenomenon is a direct result of a lower gastric acidity, as a consequence of omeprazole treatment.
- PublicationOpen AccessUltrastructural localisation of acid phosphatase in intestinal eosinophilic granule cells (EGC) of rainbow trout(Murcia : F. Hernández, 1992) Powell, Mark D.; Briand, Heather A.; Wright, Glenda M.; Burka, John F.Enzyme cytochemistry was used to investigate possible lysosome involvement in capsaicin induced degranulation of the eosinophilic granule cell (EGC) of the rainbow trout intestine. Three adult rainbow trout (Oncorhynchus mykiss) were injected intra 'k eritoneally with capsaicin in a saline vehicle (0.5 pg.g- body weight). Following a 2 hour period of incubation, the fish were killed, and a mid portion of the intestine was dissected and fixed in cold glutaraldehyde buffered with sodium cacodylate. Vibratome sections were incubated in either reaction medium containing B-glycerophosphate and cerium chloride in acetate buffer or substrate (Bglycerophosphate) deficient control medium. Sections were then refixed in osmium tetroxide and processed for electron microscopy. Acid phosphatase was found to be localised within lysosomes. The enzyme was not found in the large cytoplasmic granules under normal or capsaicin-stimulated conditions. EGCs which had migrated to the lamina propria in response to the capsaicin stimulation had a distinct multivesicular granule morphology. These multivesicular granules did not contain acid phosphatase suggesting that this form of EGC degranulation is not a lysosomally mediated event.
- PublicationOpen AccessPhotoreceptor fine structure in the southern fiddler ray (Trygonorhina fasciata)(Murcia : F. Hernández, 1992) Braekevelt, Charlie R.The fine structure of the retinal lntroduction photorecéptors has been studied by light and electron microscopy in the southern fiddler ray or guitarfish (Trygonorhina fasciata). The duplex retina of this species contains only rods and single cones in a ratio of about 40:l. No multiple receptors (double cones), no repeating pattern or mosaic of photoreceptors and no retinomotor movements of these photoreceptors were noted. The rods are cylindrical cells with inner and outer segments of the same diameter. Cones are shorter, stouter cells with a conical outer segment and a wider inner segment. Rod outer segment discs display severa1 irregular incisures to give a scalloped outline to the discs while cone outer segment discs have only a single incisure. In al1 photoreceptors a non-motile cilium joins the inner and outer segments. The inner segment is the synthetic centre of photoreceptors and in this compartment is located an accumulation of mitochondria (the ellipsoid), profiles of both rough and smooth endoplasmic reticulum, prominent Golgi zones and frequent autophagic vacuoles. The nuclei of rods and cones have much the same chromatin pattern but cone nuclei are invariably located against or particularly through the externa1 limiting membrane (ELM). Numerous Landolt's clubs which are ciliated dendrites of bipolar cells as well as Müller cell processes project through the ELM, which is composed of a series of zonulae adherentes between these cells and the photoreceptors. The synaptic region of both rods (spherules) and cones (pedicles) display both invaginated (ribbon) synapses and superficial (conventional) synapses with cones showing more sites than the rods.
- PublicationOpen AccessChanges in the ventral dermis and development of iridophores in the anadromous sea lamprey, Petromyzon marinus, during metamorphosis: an ultrastructural study(Murcia : F. Hernández, 1992) Wright, Glenda M.; McBurney, Kim M.The ultrastructural changes that take place in the ventral dermisalong with the development of iridophores were examined in the anadromous sea lamprey, Petromyzon marinus, during metamorphosis. There is a disruption of al1 components of the ventral dermis and a reformation that results in a sturcture very similar to that prior to metamorphosis. Although not a dermal component, a layer of iridophores develops directly beneath the dermis during late metamorphosis. The dermal endothelium is lost by mid metamorphosis (stage 4) and the highly organized collagenous lamellae making up the bulk of the dermis become disrupted by the migration of fibroblasts into the region. Many of these fibroblasts are involved in the degradation of the lamellae. By stage 5 of metamorphosis some fibroblasts become highly active collagen synthesizing cuboidal shaped cells that align to form a layer above the reformed dermal endothelium. New lamellae are formed by these cuboidal cells which then divide and migrate into the lamellae where they assume the characteristic attenuated appearance of fibroblasts in the adult dermal lamellae region. Iridophores first appear during stage 5 directly beneath the dermal endothelium. Reflecting platelets develop from double membraned vesicles associated with the Golgi apparatus. By late metamorphosis, stacks of trapezoidal shaped platelets fill the cytoplasm of the iridophores. The significance of the changes in the dermis during metamorphosis are discussed. This work is part of a continuing series of studies on the connective tissues in the anadromous sea lamprey.
- PublicationOpen AccessEtiology of the developing eye in myelencephalic blebs (my) mice(Murcia : F. Hernández, 1992) Center, Elizabeth M.; Polizotto, René S.The etiology of the eye defects in myelencephalic blebs (my) mutant mice has been poorly understood for almost seventy years. Embryos from 9 to 14 M days of gestation were subjected to Alcian blue 8GX staining for acidic glycosaminoglycan deposition in basement membrane structures of the developing eye in my stock and control specimens. In addition 12 day embryos were subjected to avidinbiotin- peroxidase labelling for laminin. At 9 - 9 M days of gestation more Alcian blue positive extracellular matrix was found in the region between the optic vesicle and the overlying putative lens ectoderm in the my stock embryos. By 12 days, there was an irregular and lesser amount of deposition of glycosaminoglycans in the len's capsule and in the «inner lirniting membrane~ of the presumptive neural retina; however, the deposition of laminin appeared to be greater in the inner lirniting membrane of the my eye. By 14 days, the damage to the eye in the my embryos can be quite extensive, and the deposition of glycosaminoglycans was very meager in this situation. It appears that irregular deposition of glycosaminoglycans in the extracellular matrix and possible increase in the amount of laminin in basement structures in my embryos indicate disruption of the normal histochemistry involved in the development of the eye. Altered histochemistry may in turn indicate changes in permeability between cells of the developing tissues which result in the blebbing.