Histology and histopathology Vol. 2, nº 2 (1987)

Ir a Estadísticas

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http://hdl.handle.net/10201/177470

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Anti-platelet agents reduce morphological changes of chronic hypoxic pulmonary hypertension
(Murcia : F. Hernández, 1987) Keith, lngegerd; Will, James A.; Huxtable, Ryan J.; Weir, Kenneth
The pathophysiologic mechanism by which chronic hypoxia causes pulmonary hypertension is unknown. If anti-platelet agents, or other pharmacologic interventions, altered the pulmonary vascular changes induced by hypoxia, information concerning the pathogenesis of the pulmonary hypertension or the potential therapeutic usefulness of the drugs might be obtained. In Study 1, rats exposed to chronic hypobaric hypoxia (P, = 520 mmHg) had a pulmonary arterial medial thickness of 6.7 * 0.6 p compared to 4.1 + 0.2 p * for control, normoxic rats (*p<0.05). Administration of dipyridamole (2mg/kg/day), or sulfinpyrazone (1 1 mg/ kglday) in the drinking water reduced the medial thickness to 5.0 2 0.3 p* and 5.4 2 0.5 p* respectively, thus suggesting the possible involvement of platelets in the response of the media to chronic hypoxia. In Study 2, hypoxic rats treated with the calcium blocker, flunarizine, were found to have less medial hypertrophy than a control group of hypoxic rats. This observation suggests that a decrease in transmembrane calcium flux may also reduce medial hypertrophy.
Open Access
Endocrine cells of the gastric mucosa of Rana temporaria L.
(Murcia : F. Hernández, 1987) Díaz de Rada, O.; Sesma, P.; Vazquez, J.J.
The endocrine cells of the gastric mucosa of Rana temporaria have been studied according to the ultrastructure, the staining properties of the granules with Masson Fontana's and Grimelius' silver methods, silver impregnation of Davenport on deplasticised semithin sections and immunocytochemical techniques. Seven different types of endocrine cells have been described. Six were regarded as belonging to known types: G, A, EC, ECL, D and P cells. One type was considered as unclassifiable.
Open Access
Autoradiographic localization of estrogen target cells in the spinal cord of the armadillo and baboon, a comparative study
(Murcia : F. Hernández, 1987) Weaker, Frank J.; Sheridan, Peter J.
The uptake and retention of radiolabeled estradiol by the spinal cord were examined in the baboon and the armadillo and compared to previous observations in the rat. Four females of each species were injected intracardially with 1.0-1.4 pg/kg body weight of %- estradiol and two females, one baboon and one armadillo, were injected with both labeled and 100-140 pg/kg body weight of unlabeled estradiol. One hour after the injections, the animals were killed and segments from the cervical, thoracic, lumbar and sacral cord were removed and processed for autoradiography. In the armadillo, labeling of neuronal nuclei were noted in laminae I & I1 and in alpha motor neurons. In addition, nuclei of the ependymal cells of the ventral portion of the central canal in the cervical cord concentrated radioactivity. In contrast, the baboon demonstrated only sporadic labeling of neurons in lamina I1 in all levels of the spinal cord. The comparison of our observations with that of the rat suggest that estrogen mediated sensations are probably coordinated at higher brain centers in the primate as opposed to the more primitive mammals
Open Access
GNRH induces activation of Leydig-like cells in Pleurodeles waltlii. A morphometric study
(Murcia : F. Hernández, 1987) Moya, L.; Guerrero, F.; Navas, P.; García-Herdugo, G.
The ultrastructure of the interstitial cells of the glandular tissue of Pleurodeles waltlii was studied in testis of animals obtained in early breeding season (January) under gonadotropic releasing hormone (GNRH) treatments and controls. These cells (parenchimal or Ledyig-like cells) displayed the structural characteristics of steroid-producing cells. GNRH administration for 24 hours induced a significant decrease of both medial volume and volume density of lipid droplets. On the other hand, cell volume, nucleus. mitochondria, mitochondrial cristae and tubules of smooth endoplasmic reticulum were increased. The surface density of mitochondrial cristae was also increased
Open Access
The protective effects of a prostaglandin without antisecretory properties aginst ethanol-induced injury in the rat stomach, a histologic study
(Murcia : F. Hernández, 1987) Schmidt, Carmen L.; Henagan, Julia M.; Mitchell, Philip A.; Smith, Gregory S.; Miller, Thomas A.
This study examined the effect of 2-acetyl-2- decarboxy-15(S)-15 methyl PGF,, (PGF,,) on ethanol (EtOH) induced injury in the rat stomach to determine if a PG analogue devoid of antisecretory properties could confer full or partial gastric mucosal protection. Rats were orally administered saline or PGF,, in a dose of 0.5 or 5.0 mg1Kg. Thirty minutes later animals received varying concentrations (i.e. 25%, 50%, and 100%) of EtOH orally. Five minutes following EtOH exposure, they were killed and samples taken from identical regions of the glandular mucosa for microscopic evaluation. All concentrations of EtOH tested damaged the gastric epithelium. The injury induced by 25% EtOH was almost exclusively confined to the surface epithelium and was not altered by either dose of PGF,,, pretreatment. In contrast, both 50% and 1(10% EtOH elicited comparable damage to the gastric mucosa involving both the deep and superficial mucosa of virtually the entire epithelium. The deep injury induced by these two EtOH concentrations was prevented by both the low and high dose of PGF,,. Of particular importance the 5.0 mg dose of PGF, provided complete protection (i.e. both superficial and deep) to as much as 50% of the mucosa exposed to 50% or 100% ethanol. These findings indicate that PGF?, possesses ~~cytoprotectivep*r operties involving both the superficial and deep epithelium that are dose related.

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