INTRODUCTION Despite the fact that ovarian stimulation is controlled, it is not always predictable. Because the day of human chorionic gonadotrophin (hCG) injection depends mainly on the patient's ovarian response to gonadotrophins, the day of oocyte retrieval cannot be determined in advance. As a result, oocyte retrievals are often scheduled to occur on weekends, a fact that entails at least o...

In recent years, mammalian oocytes have been proposed to have important roles in the orchestration of ovarian follicular development and fertility. To determine whether intra-oocyte Foxo3a, a component of the phosphatidylinositol 3-kinase (PI3K) signaling pathway, influences follicular development and female fertility, a transgenic mouse model was generated with constitutively active Foxo3a exp...

In mammals, oocytes are arrested at the diplotene stage of meiosis I until the pre-ovulatory luteinizing hormone (LH) surge triggers meiotic resumption through the signals in follicular granulosa cells. In this study, we show that the estradiol (E2)-estrogen receptors (ERs) system in follicular granulosa cells has a dominant role in controlling oocyte meiotic resumption in mammals. We found tha...

Oocytes undergo a range of complex processes via oogenesis, maturation, fertilization, and early embryonic development, eventually giving rise to a fully functioning organism. To understand proteome composition and diversity during maturation of human oocytes, here we have addressed crucial aspects of oocyte collection and proteome analysis, resulting in the first proteome and secretome maps of...

Oxidative stress is known as a major contributing factor involved in oocyte aging, which negatively affects oocyte quality and development after fertilization. Melatonin is an effective free radical scavenger and its metabolites AFMK and AMK are powerful detoxifiers that eliminate free radicals. In this study, we used porcine oocytes to test the hypothesis that melatonin could scavenge free rad...

Various morphological and cytological traits of oocytes and their surrounding cumulus cells may be used to select oocytes for assisted reproduction. However, even with careful selection, successful IVF and subsequent embryo development remain uncertain. The factors that ensure oocyte competence are unclear and other approaches to assessing developmental potential must be explored. With the cons...

BACKGROUND Oocyte cryopreservation remains a realistic objective, provided that more systematic approaches are applied, such as thorough analysis of the oocyte oolemma permeability to water and diverse cryoprotectants. METHODS We prospectively investigated volume changes over time at different temperatures (30 degrees C, 22 degrees C and 8 degrees C) of human metaphase II (MII) oocytes (obtai...

In Drosophila, the formation of the embryonic axes is initiated by Gurken, a transforming growth factor alpha signal from the oocyte to the posterior follicle cells, and an unknown polarising signal back to the oocyte. We report that Drosophila Merlin is specifically required only within the posterior follicle cells to initiate axis formation. Merlin mutants show defects in nuclear migration an...

We found different genotypes for the complete hydatidiform mole (CHM), placenta and co-existing fetus derived from a single in vitro fertilized human oocyte by the analysis of short tandem repeat (STR) DNA markers. The molar tissue was found to be heterozygously androgenetic. The fetus and placenta contained identical maternal, but different paternal genomes. Two models were proposed to account...

Objectives: The current study aimed to investigate the in vitro effects of physiologic concentration of adiponectin in follicular fluid of pre-ovulatory bovine ovarian follicles on: 1) the bovine oocyte maturation and the early developmental rates of bovine embryos in vitro; 2) the expression profiles of some developmentally important marker genes in the bovine cumulus cells and oocytes. Materi...