background & objectives : different energy substrates and nutrients can greatly influence oocyte nuclear and cytoplasmic maturation. effect of glucose on in-vitro oocyte maturation and subsequent early embryonic development is controversial. the objective of the present study was to verify the effect of various concentrations of glucose on cumulus-oocyte complexes maturation, fertilization and ...

Background In vitro maturation (IVM) of human oocytes has acquired increasing attention in infertility treatment with great promise. This technique is an alternative conventional in vitro fertilization-embryo transfer (IVF-ET), and can be reduced the side effects of gonadotropin stimulation such as ovarian hyperstimulation (OHSS). Oocyte maturation is a complex process including cytoplasmic and...

background: oocyte maturation and subsequent in vitro production (ivp) of embryos are affected by diverse groups of chemicals in maturation medium which are needed for successful mammalian oocyte maturation during which the dramatic cytoplasmic and nuclear reprogramming events take place. this study was designed to evaluate the effects of protein source (fetal bovine serum, fbs, and bovine seru...

Background: The developmental competence of oocytes matured in vitro (IVM) is yet far below than in vivo counterparts. Recent studies suggest that the asynchrony between nuclear/cytoplasmic maturation and the initial low/heterogeneous quality of oocytes are the most important factors affecting IVM success. We investigated whether selection of growing oocytes (based on their glucose 6- phosphate...

Efforts have intensified to successfully mature and inseminate oocytes in vitro and then culture ensuing embryos to transferable stages from a large number of mammalian species. Success varies, but generally even for the most successful species it is only possible to obtain a maximum of a 40 to 50% development of zygotes to the blastocyst stage. Reduced oocyte developmental competence is sugges...

Oocyte cryopreservation is a promising technology that could benefit women undergoing assisted reproduction. Most studies examining the effects of cryopreservation on fertilization and developmental competence have been done using metaphase II-stage oocytes, while fewer studies have focused on freezing oocytes at the germinal vesicle (GV) stage, followed by in vitro maturation. Herein, we exami...

This article briefly reviews the classical cell cycle studies using oocytes and zygotes of mainly amphibians in the past century. The discussions are focused on the investigations into the cytoplasmic factors that regulate meiosis during oocyte maturation and the initiation of mitosis during fertilisation, which were carried out in the author's lab between 1967 and 1987. This chronicle traces t...

An extended meiotic prophase is a hallmark of oogenesis. Hormonal signaling activates the CDK1/cyclin B kinase to promote oocyte meiotic maturation, which involves nuclear and cytoplasmic events. Nuclear maturation encompasses nuclear envelope breakdown, meiotic spindle assembly, and chromosome segregation. Cytoplasmic maturation involves major changes in oocyte protein translation and cytoplas...

Oocyte maturation is a complex process involving nuclear and cytoplasmic maturation. The nuclear maturation is a chromosomal segregation and the cytoplasmic maturation involves the reorganization of the cytoplasmic organelles, mRNA transcription and storage of proteins to be used during fertilization and early embryo development. The mechanism of oocyte maturation in vivo and in vitro still are...