Histology and histopathology Vol. 6, nº 2 (1991)
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- PublicationOpen AccessDevelopment of the small intestine of piglets in response to prenatal elevation of glucocorticoids(Murcia : F. Hernández, 1991) Bate, L.A.; Ireland, William P.; Connell, B.J.; Grimmelt, B.The effects of prenatal adrenal stimulation and synthetic glucocorticoicl supplementation on developrncnt of the gastro-intestinal tract of the piglet were investigated. Twelve pregnant sows were treated with either ACTH infusion. Isoflupredone injection or Saline between days I05 and 112 of gestation. Neonatal pigs were weighed. bled and sacrificed at 0 or at 6 h. Piglets sacrificed at 6 h were fed bovine colostrum. Trailsvcrse sections were prcpared from the duucienuin. i e j ~ ~ n uman cl ileum for measurcment of thc villus amplification factor (VAF) and basal membrane circunifercnce. Sows in the ACTH group showed an cle\,ation in cortisol in response to infusion: this decreased aftcr infusion and then rose again at parturition. Piglcts from both the ACTH and Saline groups had more villus surface area per unit of body weight (BW) than those born to Isotluprcdone-treated animals. The BW of the ACTH piglets was lowcr (P < 0.05) than those of piglets in the other groups. Whcn the weight of thc stomach and the Small Intestine (SI) was cxpressetl as a function of thc body weight, tlic stomach and S1:BW ratio was larger (p < 0.05) in pigs born to ACTH-treated sows. The circumfcrence of the ilcurn was larger at 6 h than at 0 h. Control pigs had a higher concentration of bovine IgG at 4 and 6 h (P < 0.05). Observations of thc light microscvpic preparations indicated a less organized epithelium in both ACTH and isotluprcdone pigs sacrificed at O Ii. Light and EM preparations of ileum from ACTH pigs sacrificed at 6 h. showcd an abundance of dark-stained vacuoles. characteristic of IgG-containing structures. These became lcss evident in piglets from the Isotlupredone group and even less so in thc control groups. The consequences of these phenomena in terms of absorptive capacity are discusscd.
- PublicationOpen AccessMicrovascular pericytes, a review of their morphological and functional characteristics(Murcia : F. Hernández, 1991) Díaz-Flores, Lucio; Gutiérrez, Ricardo; Varela, Hilda; Rancel, N.; Valladares, FranciscoA hundred years after the first description, niany aspects of pericytes reniain to be examined. Mesenchymal in origin, pericytes form an incomplete envelopment around the endothelial cells and within the microvascular basement niernhrane of capillaries and postcapillary venules. Morphologically. they appear as long, slender, polymorphic cells. showing an elongated cell body, from which arise longitudinal and circumferential branches. Cell bodies and cytoplasmic processes of pericytes. as well as the endothelial cells, are enveloped by the same basal lamina. except for where they make direct contacts with each other. The pericytet endothelial cell contacts are peg and socket. adlicsion plaques and gap junctions. making up structural mechanisms for force transmission and a possible receptor system for cells, in which the pcricyte and endothelial cells I-espond to secondary signals generated in the other cells. Electron niicroscopic studies have revealed an elaborate network of cytoplasmic filaments. Pericytc intermediate filament proteins show species and tissue differences. expressing vimentin or vimentin and desmin. The pericytes also express protein typical of contractile cells, i.e. smooth muscle-specific isoforms of actin and myosin, cyclic GMP-protein kinase and tropomyosin. A gradual transition is observed between pericytes and smooth muscle cells in both terminal a-terioles and venules. Several general functions for the pericytes have been postulated: contractability: permeability regulator: integrity maintainer; endothelial cell growth modulator; and cell progenitor with considerable mesenchymal potential.
- PublicationOpen AccessAmitosis in human adrenal cells(Murcia : F. Hernández, 1991) Magalhães, M. C.; Pignatelli, D.; Magalhães, M. M.Adrenal pieces obtained from 3 fcmalc ancl 2 ~nirle patients sho\\'cd morpl~ologicirl figures of umito4is in aclrcnirl zona ret ic~~l :~rcicsl ls. Such aspects were ohs c r \~~i~n cblo th normal and hyperactive aclrcnuls. Nuc,lci appeal-cd constricted. hea\ ill stained. \\.it11 coarse chromatin. sometimes scattered among c!toplasmic organcllcs. hut never niarginating in cre4ccntic cirps. C'lea\:~gc 01' the cells originated t\\lo hnl\,cs \\it11 a nucleolus in each pole. Rin~lcleateclc clls \vcl-c also seen in zona rcticularis. -1~Iie meaning ot' nmitosis in human aclren:rl i4 cIisc11~4ccI.
- PublicationOpen AccessCardiac and pancreatic lesions in guinea pigs infected with encephalomyocarditis. EMC, virus(Murcia : F. Hernández, 1991) Petruccelli, M.A.; Hirasawa, K.; Takeda, M.; Itagaki, S.; Doi, K.Cardiac and pancreatic lesions were observed in guinea pigs infected with 2 variants (B and D) of encephalornyocarditis (EMC) virus. Cardiac changes were characterized by focal myocardial necrosis and subsequent replacement by immature granulation tissue. and the pancrcatic ones by vacuolar degeneration of acinar cells. In the electron microscopic esaminatioiis. tlie affected cardiornyocytes showed intracellular oedema. swelling andlor partial destruction of mitochondria, and distortion and disruption of myofihrils. Intracellular vacuolization and dilatation of roughsurfaced endoplasniic reticulurn (rER) were conspicuous in the damaged pancreatic acinar cells. In addition, intracisternal granules were found in dilated rER with a high frequency. These changes were common to animals infected with the B and D variants. On the contrary, B cell alterations: i.e. degranulation and degeneration of insulin granules, were detected only in animals infected with the D variant.
- PublicationOpen AccessElectron microscopic histochemical and immunochemical analyses of heparan sulfate proteoglycan distribution in renal glomerular basement membranes(Murcia : F. Hernández, 1991) Rada, Jody A.; Carlson, E. C.Renal glomerular basement membranes (GBMs) exhibit a charge-selective barrier, comprised of anionic sites, that restrict the passage of anionic molecules into the urine. These sites are located primarily in the laminae rarae interna (LRI) and externa (LRE) of the GBM and consist of heparan sulfate proteoglycan (HSPG). Previous efforts to localize HSPG core protein within various layers of the GBM have been contradictory. In the present study when rat renal cortex blocks were treated by immersion with the cationic probe, polyethyleneimine (PEI), GBMs exhibited anionic sites concentrated primarily in the LRE and more irregularly within the LRI and lamina densa. All sites were heparitinase sensitive indicating that PE1 positive sites represent negatively charged groups associated with heparan sulfate. In order to gain information on the distribution of the HSPG protein core, antibodies to HSPG from the EHS tumor matrix [anti-(EHS) HSPG] and GBMs [anti-(GBM) HSPG] were used together with immunogold to label thin sections of Lowicryl embedded kidney cortex. Depending upon the antisera used, markedly different distributions of HSPG were obtained. Immunolabelling with anti-(GBM) HSPG suggested a distribution of HSPG which was restricted to the laminae rarae, whereas labelling with anti-(EHS) HSPG indicated that the protein core penetrates through all layers of the GBM.