background: oocyte cryopreservation is one of the most important topics in the field of assisted reproductive technology to preserve women fertility, but relationship between cryopreservation and apoptosis is still a matter of debate. the present study was aimed to investigate the effects of vitrification on apoptosis in mouse oocytes by cryotop method. method: a total of 200 germinal vesicle (...

The HCO(3)(-)/Cl(-) exchanger is quiescent in the unfertilized mouse egg but is highly active in regulating intracellular pH in the early embryo and required for normal development. We show here that the HCO(3)(-)/Cl(-) exchanger is active in first meiotic prophase (GV) oocyte but inactivated during meiotic metaphase before the MI to MII transition. Reactivation does not occur until the activat...

Controversy exists about the risk of microbiological contamination from direct contact with unsterile liquid nitrogen during oocyte vitrification. The aim of this observational study was to evaluate the effectiveness of oocyte vitrification using a high-security closed vitrification system in a donation programme. Oocyte vitrification was performed using CBS High Security closed straws (Cryo Bi...

Genital tract abnormalities and adverse pregnancy outcome are well known in women exposed in utero to diethylstilboestrol (DES). Data about adverse reproductive performance in women exposed to DES have been published, including controversial reports of menstrual dysfunction, poor responses after ovarian stimulation, oocyte maturation and fertilization abnormalities. We compared oocyte quality, ...

Resumption of oocyte meiotic maturation is driven by activation of cyclin-dependent kinase 1 (Cdk1), which phosphorylates target proteins that are important for nuclear envelope breakdown, chromosome condensation, and remodelling of the actin and microtubule cytoskeleton. As a consequence, a bipolar spindle is formed and condensed chromosomes become aligned at the metaphase plate. The spindle a...

BACKGROUND In co-cultures of pachytene spermatocytes with Sertoli cells, beta-NGF regulates the second meiotic division by blocking secondary spermatocytes in metaphase (metaphase II), and thereby lowers round spermatid formation. In vertebrates, mature oocytes are arrested at metaphase II until fertilization, because of the presence of cytostatic factor (CSF) in their cytoplasm. By analogy, we...