The purpose of the present review is to outline the current understanding on the molecular mechanisms governing various stages of oocyte maturation, transition from maternal to embryonic control and the initial steps of pre-embryo development. The cytoplasmic and nuclear maturation of the oocyte during pre-ovulatory development can be viewed as separate entities. Cytoplasmic maturation and the ...

A major challenge of assisted reproduction technologies (ARTs) is to mimic the natural environment required to sustain oocyte and embryo survival. Herein, we show that the ceramide-metabolizing enzyme, acid ceramidase (AC), is expressed in human cumulus cells and follicular fluid, essential components of this environment, and that the levels of this enzyme are positively correlated with the qua...

BACKGROUND A number of factors influence the success of oocyte cryopreservation and subsequent ICSI. The aim of the present study is to establish the ideal time, after oocyte retrieval, for human oocyte cryopreservation via slow freezing/rapid thawing protocol with 0.3 M sucrose concentration in cryoprotectant solution (SF/RT 0.3 M). METHODS Retrospective study with 75 patients on the clinica...

We carried out a prospective study of 221 healthy women who were attempting pregnancy. During the study, women collected daily urine samples and kept daily records of intercourse. Ovulation and early pregnancy losses were later identified by immunoassays of urinary human chorionic gonadotrophin and steroid metabolites. We have used these data to examine whether the risk of early pregnancy loss ...

Cryopreservation has been a technique used in reproductive endocrinology and infertility medicine since the early 1980s. Embryo cryopreservation, specifically, has been widely used in many in vitro fertilization (IVF) programs worldwide. This method has been well studied and is a common strategy employed for storing supernumerary embryos after IVF cycles, among other applications. Oocyte cryopr...

It is widely recognized that bi-directional communication exists between the human oocyte and cumulus cells (CCs) which is essential for the production of competent oocytes. CCs originate from granulosa cells (GCs) which differentiate into mural GCs and CCs during follicular antrum formation. CCs are biologically distinct from other follicular cells and perform specialized roles, transmitting s...

The mammalian oocyte and embryo display considerable plasticity. Even in sub-optimal conditions, as in vitro environment may be certainly considered, the oocyte is able to mature, face fertilization and develop first into an embryo and finally to a live offspring. Such ability has encouraged, over the decades, the development of numerous in vitro assisted reproductive technologies (ART) in seve...

Although human diseases of retrotransposition-derived etiology have been documented, retrotransposon RNA expression and the occurrence of retrotransposition events in the human oocyte are not studied. We investigated the RNA expression of L1 and HERV-K10 retrotransposons in human oocytes by RT-PCR analysis with designed primers. Using denucleated germinal vesicles (GVs), we detected RT-PCR prod...

STUDY QUESTION Does heparin ablate the advantageous effects of cyclic adenosine mono-phosphate (cAMP) modulators during pre-in vitro maturation (IVM) and have a deleterious effect in standard oocyte IVM? SUMMARY ANSWER Heparin interrupts energy metabolism and meiotic progression and adversely affects subsequent development of oocytes under conditions of elevated cAMP levels in cumulus-oocyte ...