Pregnancy achieved with sperm from a patient with globozoospermia is rare, even after ICSI, since the activation of the oocyte may not occur in this disorder. Therefore, activation of the oocytes by piezoelectricity or calcium ionophores has been suggested, although spontaneous activation of the oocyte after ICSI has been reported in some cases. We report a successful pregnancy in a couple in w...

Previous studies indicate that stress damages oocytes with increased secretion of glucorticoids. However, although injection of female mice with cortisol decreased oocyte competence, exposure of mouse oocytes directly to physiological or stress-induced concentrations of glucorticoids did not affect oocyte maturation and embryo development. This study has explored the mechanisms by which glucoco...

Fertilization involves an initial, highly localized signal delivered by the sperm, which becomes amplified by a signal transduction cascade to impact the entire oocyte cytoplasm. The zebrafish oocyte presents a unique opportunity to study this process since fertilization always occurs at the micropyle, allowing the investigator to image the earliest steps in the oocyte activation process. The o...

Bovine oocytes matured in vitro were stimulated by a single pulse of direct current (DC), then cultured for 0.5-6 h and evaluated by light (LM) and transmission electron microscopy (TEM). At the light microscopic level, the beginning of oocyte chromatin decondensation was first observed 3 h post-activation (14%). A well-developed pronucleus with evenly granulated nucleoplasm surrounded by nucle...

introduction: the incidence of sperm and oocyte premature chromosome condensation (pcc) in the failed fertilized oocytes that were taken after routine in viro fertilization (ivf) and intracytoplasmic sperm injection (icsi) programs were investigated. materials and methods: in this study, 364 air-dried preparations of failed fertilized oocytes after either ivf or ocsi procedures were analyzed. t...

Protein kinase C (PKC) is involved in gonadotrophin-induced oocyte maturation. In the present study, we investigated the role of specific PKC isoforms in the process of follicle-stimulating hormone (FSH)-induced oocyte meiotic resumption. Small antral follicles (200-300 µm in diameter) were isolated from immature mice and cultured in vitro. FSH significantly induced follicle-enclosed oocytes (F...