Histology and histopathology Vol. 7, nº 2 (1992)
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- PublicationOpen AccessMorphology and functional responses of isolated inner adrenocortical cells of rats infuse with interleukin-B(Murcia : F. Hernández, 1992) Rebuffat, P.; Malendowicz, L.K.; Andreis, P.G.; Meneghelli, V.; Kasprzak, A.; Nussdorfer, G.G.The effects of the prolon Ye d infusion with interleukin-1B (IL-10) (20 pM.kg- .min- ') on the function and morphology of the isolated inner cells of the rat adrenal cortex were investigated. After 3 and 5 days of IL-1B infusion, the level of circulating ACTH was below the control level, while the plasma concentration of corticosterone was strikingly elevated. After 5 days of infusion, isolated inner adrenocortical cells showed an enhanced basal and ACTH-stimulated corticosterone secretion, and showed a conspicuous hypertrophy. The acute exposure to IL-1B 10" M did not affect the secretory activity of dispersed cell from either control or IL-lB-infused rats. These findings indicate that the prolonged exposure to high levels of circulating IL-lB, like those occurring during chronic inflammatory diseases, is able to enhance the growth and steroidogenic (glucocorticoid) capacity of the rat inner adrenocortical zones. Moreover, they suggest that the mechanism underlying this adrenocorticotrophic effect of IL-1B does not involve either a stimulation of the hypophyseal ACTH release or a direct stimulatory effect of monokine on adrenocortical cells. It is suggested that IL-1B may activate an intra-adrenal paracrine regulatory mechanism.
- 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.
- 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 AccessIntimal thickening in arterial autografts. Role of the adventitial layer(Murcia : F. Hernández, 1992) Buján, J.; Bellón, J.M.; Gianonatti, M.C.; Golitsin, A.In the present work, the repairing response of the iliac arterial wall is studied after carrying out autografts in segments of these vessels. The formation of the intimal hyperplasia, which occurred in al1 the cases, was followed at the biochemical leve1 (tritium thymidine incorporation) and with light and electron microscopy. The adventitial layer showed great activity during the repairing process. We believe that it plays an important role not only in neoadventitial formation, but also in myointimal raising.