António J Cidadão

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BACKGROUND Current ovarian tissue cryopreservation protocols have yet to be assessed in terms of somatic-germ cell interaction. Accordingly, post-thaw analysis of antral follicles can yield relevant data on the disruption of the granulosa-oocyte interface. METHODS We compared fresh mouse ovarian tissue with tissues that had been either cryopreserved using(More)
Intermediate filament-nuclear matrix interactions were studied in cultured rat ventral prostate cells and isolated rat uterine epithelial cells. Cytokeratin filaments were identified by immunoelectron microscopy. In addition to conventional thin section of Triton X-100 treated cells, subcellular residues composed of intermediate filaments and nuclear matrix(More)
We studied the distribution of fibronectin (FN) in rat uterus, rat tail tendon, and rooster comb, using LM and EM immunocytochemistry. Special attention was paid to the interaction of FN with collagen (COL). Various labeling protocols and dot-blot experiments were performed to confirm the results. Under conditions of labeling specificity, FN distribution(More)
The distribution patterns of rat and mouse uterine glycosaminoglycans (GAGs), as well as their modulation by estradiol (E2) and/or progesterone (P), were investigated using monoclonal antibodies (MABs) directed against chondroitin- (CS)/dermatan sulfates (DS), keratan sulfate (KS) and a trophoblast GAG. The localization of GAGs in relation to collagens (I,(More)
Calcium signalling is involved in important events in oocytes, such as meiotic competence acquisition. We have previously demonstrated the positive influence of animal age and gonadotropin stimulation in vivo regarding the ability of oocytes recovered from preantral follicles to exhibit calcium spikes. In the present work we determined whether preantral(More)
In this study we performed a systematic comparative analysis of two culture environments-flat/adhesive liquid and three-dimensional collagen gel-upon in vitro ovarian follicle development. We paid particular attention to the effects of in vitro environments upon the preservation of follicular structure and of peri- and intra-follicular extracellular matrix.(More)
The interactions between plasma fibronectin (FN), glycosaminoglycans (GAGs) and native collagen (COL) fibrils were studied in artificial three-dimensional extracellular matrices. FN-COL binding was investigated using rotary shadowed platinum-carbon replicas, EM immunocytochemistry and FN-gold complexes. GAGs were visualized using cationic dyes and anti-GAG(More)
The action of gonadotropins upon the oocyte is known to be crucial at later stages of follicular development in mammals. However, its influence on oocytes at early preantral stages is still a matter of debate. In the present study we evaluated the onset of mouse oocyte's capacity to exhibit calcium spikes during preantral stages of follicular development,(More)