The genetic status of oocytes can be determined by polar body (PB) analysis. Following PB extraction, a genetic evaluation is performed. As each PB contains the complementary genetic material of the oocyte, PB analysis reveals information about its genetic status. Genetically altered oocytes may then be excluded from in vitro fertilization. The aim of our study was to evaluate laser microdissec...

BACKGROUND Failures in expression of zona proteins correlate to subfertility in animals. Low expression of the zona proteins by the growing human oocyte may indicate reduced developmental potential. Therefore, we non-invasively analysed the thickness and the structure of the zona pellucida (ZP) of human oocytes with respect to embryo fate after ICSI. METHODS Retardance magnitude and thickness...

BACKGROUND Human menopausal gonadotropin (hMG) has contributed many improvements to human assisted reproduction. However, effects of hMG on oocyte development and clinical results remain controversial. OBJECTIVE This study was conducted to investigate the effects of hMG on the zona pellucida of oocytes, as well as clinical results in superovulation treatment. MATERIALS AND METHODS This retr...

In order to study the three-dimensional topographic arrangement of the oocyte and zona pellucida, follicular cells and follicle microvasculature, this study applied alkali maceration methods for tissue exposure, the ruthenium red-detergent method for the extracellular matrix visualization, and the vascular corrosion cast technique to rabbits, guinea-pigs and mice ovaries at different stages of ...

Previous studies have demonstrated that the use of recombinant human follicle stimulating hormone (rhFSH) for ovarian stimulation may be associated with a better outcome than human menopausal gonadotrophin (HMG), probably due to the absence of LH, higher FSH bioactivity and better quality of oocytes and embryos when rhFSH is used. Very few studies have examined the effects of different gonadotr...

Changes occurring as the prophase I oocyte matures to metaphase II are critical for the acquisition of competence for normal egg activation and early embryogenesis. A prophase I oocyte cannot respond to a fertilizing sperm as a metaphase II egg does, including the ability to prevent polyspermic fertilization. Studies here demonstrate that the competence for the membrane block to polyspermy is d...

In the present study, various developmental stages of Liza aurata oocyte, especially IV and V stages have been described. On the basis of histological investigations, oocyte development in L. aurata comprises immature (I), the early maturing (II), the late maturing (III), mature (IV), ripe (V), and spent (VI) stages. In the stages I and II, nucleus occupied large volume of oocyte. Vacuolization...

The interaction of preincubated ram sperm with zona-free hamster oocytes was studied by scanning and transmission electron microscopy. The behaviour of the sperm cells was quite different, depending on whether the acrosomal reaction had taken place or not. The apical ridge of intact spermatozoa contacted the oocyte surface, and egg microvilli spread onto the anterior segment but no fusion ensue...