OBJECTIVE To evaluate the maturation and post-thaw survival rates of immature oocytes to determine whether in vitro maturation (IVM) should be attempted prior to or after cryopreservation. DESIGN Nonrandomized observational study. SETTING Private academic and clinical reproductive center. PATIENT(S) Patients (n = 71) who donated immature unusable oocytes after vaginal oocyte retrieval (VO...

The significance of the presence of coarse dark granules in the perivitelline space of oocytes has not been studied before. The study included 2288 intact oocytes [2063 in metaphase II (MII), 136 in metaphase I (MI), and 89 in germinal vesicle (GV)] retrieved in 206 intracytoplasmic sperm injection cycles stimulated by a long agonist protocol. The incidence of granules varied with oocyte maturi...

BACKGROUND Oocyte maturation and preimplantation embryo development are controlled by array of genes that are post-transcriptionally regulated by microRNAs. With respect to this, previously, we identified altered expression of microRNA-130b (miR-130b) during oocyte maturation. Here, we aimed to investigate the role of miR-130b in bovine granulosa and cumulus cell function, oocyte maturation and...

BACKGROUND Using fluorescence imaging, an a posteriori multiparametric analysis was performed of human oocytes which failed to give pronucleated zygotes after IVF in cases of very low rates of fertilization or complete fertilization failure. METHODS The analysis included: (i) the state of the maternal and paternal chromatin; (ii) quality of the metaphase II oocytes; and (iii) cortical granule...

A truncated form of the c-kit tyrosine kinase receptor, corresponding to the phosphotransferase portion of the cytoplasmic catalytic domain and the carboxyterminus (tr-kit), is accumulated during late mouse spermiogenesis. Here we report that tr-kit is specifically localized in the residual sperm cytoplasm, with maximal accumulation in the midpiece of the flagellum, suggesting that it can enter...

OBJECTIVE To investigate the protective effect of L-carnitine (LC) against deleterious substances present in the peritoneal fluid (PF) of patients with endometriosis, which may affect the oocyte cytoskeleton and embryogenesis. DESIGN Experimental study. SETTING Research embryology laboratory at an academic hospital. PATIENT(S) Frozen metaphase II mouse oocytes and embryos. INTERVENTION(...

Recently ovulated mouse oocytes at the Metaphase II stage undergo parthenogenetic activation (as indicated by the formation of pronuclei) when incubated for 6 h in the presence of cycloheximide or puromycin; the activation response increases progressively with the concentration of inhibitor. Activation is induced with concentrations of cycloheximide that depress protein synthesis by more than 7...

BACKGROUND Given the importance of timing of denudation and oocyte injection during assisted reproductive technology cycles, a study was undertaken of the impact of timing on the outcome of intracytoplasmic sperm injection in a cohort of patients from a private in vitro fertilization center. METHODS The study included patients who underwent fresh intracytoplasmic sperm injection-embryo transf...

Fusion of large and small karyoplasts produced from metaphase II mouse oocytes with interphase blastomeres from 2-cell and 8-cell embryos (volume ratio of partners, 1:1) results in premature chromosome condensation (PCC) of the interphase nucleus in the majority of the fusion products (hybrids). Fused under the same experimental protocol, oocyte-derived cytoplasts also induce PCC of the blastom...

Mature mammalian eggs are ovulated arrested at meiotic metaphase II. Sperm break this arrest by an oscillatory Ca(2+) signal that is necessary and sufficient for the two immediate events of egg activation: cell cycle resumption and cortical granule release. Previous work has suggested that cell cycle resumption, but not cortical granule release, is mediated by calmodulin-dependent protein kinas...