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.

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

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