Background: The meiotic spindle plays an important role in the oocyte during chromosome alignment and separation at meiosis. The zona pellucid (ZP) is a dynamic matrix composed of filaments with the properties that might reflect the history of oocyte cytoplasmic maturation. Since, spindle and ZP in living oocytes are highly birefringent, their structures can be viewed noninvasively by using a P...

Oocyte cryopreservation in carnivores can significantly improve assisted reproductive technologies in animal breeding and preservation programs for endangered species. However, the cooling process severely affects the integrity and the survival of the oocyte after thawing and may irreversibly compromise its subsequent developmental capability. In the present study, two different methods of oocy...

objective: retinoids are recognized as important regulators of cell differention and tissue function. previous studies, performed both in vivo and in vitro, indicate that retinoids influence several reproductive events. in this study, we investigated the effect of all-trans retinoic acid (t-ra) on maturation and fertilization rate of immature oocytes (germinal vesicle). materials and methods: g...

The effects of passive immunoneutralization of endogenous inhibin on ovulation rate in immature rats were investigated. Efficiency of superovulation on production of fertilized oocytes was compared between the inhibin antiserum (inhibin-AS) and equine chorionic gonadotropin (eCG) protocols. Immature female Wistar strain rats were superovulated with a single injection of 100-200 microl inhibin-A...

Objective In vitro maturation (IVM) is an artificial reproductive technology in which immature oocytes are harvested from the ovaries and subsequently matured in vitro. IVM does not require ovarian hyperstimulation and thus the risk of ovarian hyperstimulation syndrome (OHSS) is avoided. In this multicenter prospective cohort study we assessed the live birth rate per initiated in vitro maturati...

Lampbrush chromosomes from oocytes of the amphibian Triturus cristatus have been used to examine the role of histone acetylation in transcription by indirect immunofluorescence with antisera to H4 acetylated at specific lysine residues. Electrophoresis on acid-urea-Triton gels and Western blotting have confirmed the specificity of these antisera and defined the order in which particular lysine ...

BACKGROUND Relaxin is a small peptide also known as pregnancy hormone in many mammals. It is synthesized by both male and female tissues, and its secretions are found in various body fluids such as plasma serum, ovarian follicular fluid, utero-oviduct secretions, and seminal plasma of many mammals, including pigs. However, the presence and effects of relaxin in porcine gametes and embryos are s...

Studies were conducted to compare viability of immature buffalo oocytes vitrified in different types of cryoprotectants on the post-thaw morphological appearance, the in vitro maturation and developmental competence of buffalo oocytes. The vitrification solution (VS) consisted of Dulbecco’s phosphate buffered saline (DPBS) supplemented with 0.5 M sucrose, 0.4% bovine serum albumin (BSA) and dif...

Nuclei of frog oocytes were isolated, fixed in OsO(4) or KMnO(4), and washed. Nuclear envelopes were then dissected off, placed on grids, and air-dried for electron microscopy. Envelopes from immature oocytes at the stage of beginning yolk deposition were compared with those from mature oocytes. Envelopes from the immature stage had "pores" whose annuli contained more material and showed centra...

BACKGROUND The understanding of the mechanisms regulating human oocyte maturation is still rudimentary. We have identified transcripts differentially expressed between immature and mature oocytes and cumulus cells. METHODS Using oligonucleotide microarrays, genome-wide gene expression was studied in pooled immature and mature oocytes or cumulus cells from patients who underwent IVF. RESULTS...