Componentes celulares y fosfatasa alcalina placentaria en la infección por T. cruzi / Cellular components and placental alkaline phosphatase in Trypanosoma cruzi infection

Trypanosoma cruzi induces changes in the protein pattern of human placenta syncytiotrophoblast. Placental alkaline phosphatase (PLAP) is a glycoenzyme anchored to the membrane by a glycosyl-phosphatidylinositol molecule. PLAP activity and its presence was altered by the parasite in cultures of human placental villi and HEp2 cells with T.cruzi. The cells treated before the cultures with agents which affect PILAP or glycosyl-phosphatidylinositol (antibodies, PL-C, genistein, lithium) presented less parasitic invasion than the control ones. It was also observed a modification in the pattern of actine filaments of the host cells infected. We concluded that PLAP would participate in the process of T. cruzi invasion into placental syncitiotrophoblast cells, by a mechanism that involves hydrolysis of the glycosyl-phosphatidylinositol molecules, the activation of tyrosine kinase proteins, the increase of cytosolic calcium and the rearrangement of actine filaments of the host cells.

Aggregatory behaviour of platelets incubated with subcellular fractions of normal and chagasic human syncytiotrophoblast

The surface of human syncytiotrophoblast does not induce maternal blood platelet aggregation even though it is not an endothelium. It can be surmised that as occurs in endothelial injury the subcellular components of the syncytiotrophoblast may have pro- or antiaggregatory activity. During congenital Chagas' disease which is associated to trophoblast lesions, platelets may play a role in the development of T. cruzi-induced placentitis. In the present work the aggregatory behaviour of normal human blood platelets was recorded after their challenging with subcellular fractions of syncytiotrophoblast isolated from normal and chagasic women. Nuclear, Mitochondrial, Microsomal and Supernatant fractions isolated from normal and chagasic syncytiotrophoblast failed to induce per se any aggregatory reaction on platelets. When samples of platelet-rich plasma (PRP) were preincubated with normal and chagasic nuclear fractions and then stimulated with collagen at threshold level (CT-PRP) an inhibition of the aggregatory response was observed. Treatment of CT-PRP with normal and chagasic mitochondrial fractions induced inhibition of platelet aggregation whereas only chagasic fraction reduced latency time. Microsomal fraction from normal placentas showed no significant effects on platelet aggregation. It is concluded that subcellular fractions of normal human syncytiotrophoblast do not exhibit any effect on platelet aggregation, whereas those subcellular fractions enriched in intracellular membrane components isolated from chagasic placentas inhibit platelet aggregation.

Embryogeny of human labial glands: a structural, ultrastructural and cytochemical study

A histochemical study of labial glands was performed to compare the different stages of differentiation with those of lingual glands previously studied. Labial glands of 8 to 32 week old human fetuses were analyzed with Hematoxylin/eosine, PAS, Cason, Alcian blue, Toluidine blue, methenamine/silver, TEM and Ruthenium red techniques. At 8-10 weeks various differentiation phases of cell cords originated in the epithelium of the labial mucosa were observed. Acinar buds had PAS positive, alcianophilic and metachromatic material in the lumen of 14 week labial glands. The excretory ducts featured similar characteristics. At 24 weeks groups of mucous and seromucous acini were identified and the mucosubstances increased in the 32 week old fetuses. These results show that the labial glands are histophysiologically differentiated at an earlier stage of development (14 weeks) as compared to lingual glands (20 weeks). However, mucosubstance production would begin during the early phases of embryogenesis for both labial and lingual glands.

Prenatal development of human palatine glands: a structural and cytochemical study

La histogénesis de las glándulas palatinas fue estudiada desde el punto de vista estructural y citoquímico en embriones y fetos humanos de 8 a 32 semanas de desarrollo. Los primordios glandulares aparecían a las 12 semanas de vida intrauterina. Los extremos distales redondeados de los cordones epiteliales y el mesénquima circundante mostraban abundantes gránulos PAS positivos y alcianofílicos. A las 14 semanas las piezas secretorias terminales y el sistema ductal presentaban diferentes estadios de diferenciación estructural. Predominaban los acinos mucosos con escasos acinos mixtos, en tanto que los acinos serosos aparecían ocasionalmente. Entre las 20 y 24 semanas los acinos mucosos coloreados con azul de toluidina presentaban diferentes grados de metacromasia aún dentro de células de un mismo acino. En los conductos se identificaban células metacromáticas intercaladas con células basófilas en la cubierta epitelial. Estos hallazgos sugieren que las glándulas palatinas presentan un material histofisiológico típico entre las 14 y 20 semanas. La presencia de sustancias secretorias PAS positivas, alcianofílicas y metacromáticas en la luz acinar y contenido luminal de los conductos nos sugiere que la secreción de mucinas se inicia en la vida intrauterina

Evolución embriológica del órgano lingual del pollo / [Embryological development of the chick tongue]

Evolutionary, structural, ultrastructural and cytochemical studies (PAS, alcian blue, toluidine blue, Ruthenium red) were performed in chick tongues 7 to 19 days development, with the aim of observing the histomorphological changes during growth and differentiation. At 7 days the tongue was covered by a flat epithelium without cornification, with four cell lines. As an axis was observed a central hyaline-cartilaginous skeleton surrounded by mesenchyma. Since 11 days appeared glandular buds and canalized cell cords united trough complexes. At 15 days the epithelial thickness increased remarkably. The subepithelial connective tissue, already notably differentiated, formed papillae. Glandular acini contained PAS positive, alcianophilic, metachromatic and positive ruthenium red substance. Ultrastructurally, glands showed clear cells, with decreased electronic density and organoids randomly distributed and dark cells having electrodense cytoplasm and more organized organoids. At 19 days the epithelium was cornified in the tongue anterior half. A net increment of glycoconjugates was detected in glands. These observations show: 1) lingual glands secrete mucins since 15 days of embryonic development; 2) the cornified anterior epithelium is the result of a genetic pattern and not of a later functional adaptation to the type of feeding (grain eating birds).

Evolución morfohistoquímica del mesénquima en glándulas labiales fetales humanas / [Morphohistochemical development of mesenchyme in human fetal labial glands]

The structural and histochemical patterns of the salivary mesenchyma were analysed in relation to the epithelium of the labial glands during the embryonic development to correlate the structural and histochemical characteristics in both tissues during the histogenesis. Samples of human fetal lips were analysed using H/E, PAS, Cason, Alcian blue, Toluidine blue and Methenamine/silver. The process of glandular histogenesis begun between 8 to 10 weeks. The mesenchyma surrounding the glandular buds had PAS positive granulations which were also alcianophilic, metachromatic and periodatoreactive. Periodatoreactive collagenous fibrillae, reticular cells and nervous fibers of considerable diameter were observed. Basement membranes were PAS positive, alcianophilic and discontinuous. At 12 weeks the mesenchyma differentiated as loose connective tissue which produced a delicate periglandular capsule with fibroblast and collagenous fibrillae. From 20 to 24 weeks the acini were structurally and histochemically differentiated as serous, mucous and mixed. It was postulated that the periglandular mesenchyma would play and important role in the morphogenetic process in relation to the histochemical identification of molecules which have a specific biological functions in the epithelium-mesenchyma interactions during organogenesis.

Structural and cytochemical modifications of the developing human lingual mucosa

Propôs-se determinar as variaçöes citoquímicas das mucossubstâncias da mucosa dorsal da língua em relaçäo com suas mudanças estruturais, durante a organogênese. Utilizaram-se amostras de 8 a 32 semanas de desenvolvimento, empregando-se as seguintes técnicas: Hematoxilina e eosina, PAS, Alcian blue a pH 2.5 e 1.0, Azul toluidina a pH 3.8, Feulgen e metenamina/prata. Observamos que o número de camadas celulares do epitélio aumenta de 3 a 9, acompanhado de um notável aumento de elementos fibrilares do órion, com diminuiçäo de mucossubstâncias e células indiferenciadas primitivas. Detectamos pequenas granulaçöes metacromáticas na 8ª semana, as quais confluem ao final do desenolvimento. As glicoproteínas da membrana basal se fazem mais notáveis durante a diferenciaçäo. Postula-se que seriam produzidas primeiro, as glicoproteínas e, em menor proporçäo, glicosaminolicanos, os quais aumentam concomitantemente com as fibras reticulares e colágenas. Este processo induziria uma multiplicaçäo celular manifesta e gradual no epilélio superficial e na diferenciaçäo das papilas linguais

Morfogénesis de las glándulas linguales del embrión de pollo

Se realizó el estudio citoquímico y ultraestructural de las glándulas linguales del embrión de pollo con el objeto de analizar el desarrollo morfogenético y los glicoconjugados elaborados por las mismas para inferir sus posibles significancias histofisiológicas con referencia a las glándulas salivales de esta especie. Se emplearon lengua de embriones de pollo de 7 a 19 días de incubación las que se procesaron para su estudio ultraestructural y citoquímico (Rojo de Rutenio, PAS, Alcian blue, Azul de Toluidina). A los 11 días aparecián esbozos y cordones celulares canalizados cuyas células se relacionaban mediante complejos de unión. No se detectó reacción positiva para mucinas. A partir de los 15 días los acinos estaban bien diferenciados, con gránulos secretorios PAS positivos, alcianofílicos y metacromáticos. Poseían organelas típicas de la síntesis proteica y secreción luminal Rojo de Rutenio positiva, alcianofílica, metacromática y PAS positiva. A los 19 días se detectó un marcado incremento de las mucinas. Estas observaciones demuestran que las glándulas linguales están citoquímica y ultraestructuralmente diferenciadas desde los 15 días del desarrollo y contribuirán por medio de los glicoconjugados como ya ha sido establecido a la lubricación de los alimentos. Además podrían iniciar el proceso digestivo de los mismos y protegerían a la mucosa bucal, evitando su deshidratación y la proliferación de gérmenes patógenos