Histochemical detection of vitamins D, E and cholesterol in the tailfin rays of the teleost Tilapia rendalli

As nadadeiras dos teleósteos säo constituídas por unidades esqueléticas segmentares denominadas lepidotriquiais ou raios. Essas nadadeiras estäo envolvidas em processos regenerativos: assim, o conhecimento de sua estruturaçäo normal é de fundamental importância tanto para a compreensäo do processo de crescimento como de sua regeneraçäo. Com o objetivo de detectar substâncias lipídicas, as nadadeiras caudais foram fixadas pela formalina contendo bicloreto de cálcio a 3 por cento por 24 horas, à temperatura ambiente. Cortes com 10um de espessura, obtidos em micrótomo de congelaçäo foram submetidos às seguintes reaçöes histoquímicas específicas para lipídios: 1) Permanganato de Potássio Alcalino - Azul de Toluidina, para detecçäo de vitamina D; 2) Acido Perfórmico-Azul de Toluidina, para detecçäo de vitamina E e 3) Acido Peracético-Azul de Toluidina, para detecçäo de colesterol. Os controles para os testes histoquímicos 1, 2 e 3 foram feitos omitindo-se o agente oxidante. Reaçöes positivas obtidas para as reaçöes 1, 2 e 3 demonstraram a presença de vitamina D, E e colesterol nos raios das nadadeiras caudais da espécie Tilapia rendalli

Histochemical demonstration of phospholipid containing choline in the cytoplasm of murine decidual cells.

The localization of lipids in the endometrium of virgin and 6- to 9-day-pregnant mice was detected by histochemical methods. Total lipids (as shown by staining with Sudan black) and phospholipids containing choline (PCC) were detected. Sections subjected to reactions that have been proposed for the demonstration of vitamins E and D and cholesterol gave negative results. In the virgin animals, lipids were found in epithelial cells but not in the endometrial storma. On the other hand in the pregnant animals, the endometrial stroma contained both Sudan-black-stained lipids and PCC. Maximal staining was reached on day 8 of pregnancy. The staining was more conspicuous in the more differentiated decidual cells adjacent to the embryos than in the less differentiated predicidual cells. The nondecidualized stroma, situated peripherally near the myometrium did not stain for lipids. In the cytoplasm of decidual cells the reaction for PCC was observed in the form of granules, which were often arranged in groups surrounding the nuclei. We suggest that decidual cells store PCC to be mobilized as a precursor for mediators of decidualization, such as prostaglandins, that would act as paracrine inducers of the decidual reaction.