William S. B. Yeung

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Zona-binding inhibitory factor-1 (ZIF-1), a glycoprotein in human follicular fluid, reduces the binding of spermatozoa to the zona pellucida. ZIF-1 has a number of properties similar to those of glycodelin-A from human follicular fluid. The objective of this study was to compare the biochemical characteristics of these two glycoproteins. N-terminal(More)
Glycodelin is an example of a glycoprotein whose complex-type glycans mediate biological actions in human reproduction and immune reactions. Being attached to an identical protein backbone, glycodelin oligosaccharides vary significantly from one reproductive tissue to another and have an effect on its own secretion and role in cell communication. For(More)
OBJECTIVES Levels of maternal serum markers of fetal Down syndrome in pregnancies conceived after assisted reproduction are different from those of normal spontaneous pregnancies. The present study examined the effects of conventional in-vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI) and embryo cryopreservation on nuchal translucency(More)
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(More)
High oestradiol concentrations may be detrimental to the success of in-vitro fertilization (IVF) treatment. A total of 1122 women aged <40 years who were undergoing their first IVF cycle were evaluated retrospectively. Serum oestradiol concentrations on the day of human chorionic gonadotrophin (HCG) administration were categorized into three groups: group A(More)
OBJECTIVE To report the results of in vitro fertilization and embryo transfer (IVF/ET) performed during natural cycles. STUDY DESIGN A prospective clinical study. RESULTS Thirty-two cycles were started in 19 patients who had regular ovulatory cycles and tubal factors or unexplained infertility only as the cause of infertility. Egg collection was(More)
BACKGROUND Embryos produced by in vitro fertilization (IVF) have a high level of aneuploidy, which is believed to be a major factor affecting the success of human assisted reproduction treatment. The aneuploidy rate of cleavage stage embryos based on 1-2 biopsied blastomeres has been well-reported, however, the true aneuploidy rate of whole embryos remain(More)
Human oviductal cells stimulate embryo development in vitro partly by the production of embryotrophic glycoproteins. The identity of these glycoproteins is not yet known mainly because oviductal samples are limited and that the cultured parental oviductal cells cannot produce sufficient amount of embryotrophic factors for characterization. In this study,(More)
OBJECTIVE To study the factors affecting the incidence of polyploidy in an assisted reproduction program. DESIGN Retrospective analysis. SETTING University-based subfertility clinic. PATIENTS AND METHODS Subfertile patients were treated in 163 treatment cycles of in vitro fertilization (IVF) or pronuclear stage tubal transfer (PROST). The relationship(More)
Perfluorooctanesulfonate (PFOS) was produced and used by various industries and in consumer products. Because of its persistence, it is ubiquitous in air, water, soil, wildlife, and humans. Although the adverse effects of PFOS on male fertility have been reported, the underlying mechanisms have not yet been elucidated. Here, for the first time, the effects(More)