in recent years, preservation of fertility in women has been of great importance, especially in patients exposed to deleterious conditions on fertility. thus, cryopre-servation of human gametes, embryos and ovarian tissue has become an essential part of assisted reproduction. this approach limits the number of embryos transferred, while supernumerary oocytes and/ or embryos can be used in subse...

BACKGROUND Embryo quality may be accurately assessed as early as the pronuclear zygote phase, as shown in recent studies. However, it is not known whether good quality zygotes are destined to become good quality cleavage stage embryos and blastocysts. METHODS In this retrospective study, 86 intracytoplasmic sperm injection-embryo transfer cycles were studied where each available embryo was sc...

BACKGROUND Identification of embryos with high implantation potential remains a challenge in in vitro fertilization (IVF). Subjective pronuclear (PN) zygote scoring systems have been developed for that purpose. The aim of this work was to provide a software tool that enables objective measuring of morphological characteristics of the human PN zygote. METHODS A computer program was created to ...

BACKGROUND Pronuclear (PN) zygote morphology has been proposed as a useful tool for selecting the best embryos for transfer. METHODS PN morphology was recorded in 888 zygotes and classified according to similar/different PN size [groups A (n = 816) and B (n = 72)] and to the number, distribution and synchrony of nucleolar precursor bodies (NPB): subgroup I, pronuclei with 3-4 polarized NPB; s...

BACKGROUND IVF occasionally produces aneuploid zygotes with one or three pronuclei (PN). Routinely, these zygotes are discarded. The aim of this work was to establish human embryonic stem cell (hESC) lines from blastocysts resulting from abnormal fertilization. METHODS Abnormally fertilized zygotes were cultured to the blastocyst stage and, following zona pellucida digestion, zona-free blasto...

I N a previous paper (LIFSCHYTZ and FALK 1969b) we showed that by using the specific interaction pn-K-pn (prune--Killer-prune) we could construct an efficient screening system in which the products of reversions in the p n and K-pn loci were the only viable male-progeny. The few female progeny that survived served for estimating the number of tested zygotes. K p n is a dominant mutant, interact...

During oocyte growth in the ovary, the nucleolus is mainly responsible for ribosome biogenesis. However, in the fully-grown oocyte, all transcription ceases, including ribosomal RNA synthesis, and the nucleolus adopts a specific monotonous fibrillar morphology without chromatin. The function of this inactive nucleolus in oocytes and embryos is still unknown. We previously reported that the embr...

Abstract Study question What are the neonatal outcomes of fresh/frozen-thawed embryos derived from monopronuclear zygotes (1PN)? Is there any influence method fertilization? Summary answer A total 231 monoembryonic transfers (TF) fresh or frozen/thawed 1PN allows to birth twenty-seven healthy babies. is known already Zygotes were classified 16 18 hours post insemination according extrusion seco...

Injection of mammalian sperm extracts or cRNA of the sperm-specific phospholipase C zeta 1 (PLCZ1) has been shown to trigger repetitive oscillations in the concentration of free calcium ([Ca(2+)](i)), leading to oocyte activation and embryo development in all mammals studied to date. While PLCZ1 has cross-species activity, it has also been observed that species-specific differences may exist in...

So far, all preimplantation genetic diagnosis (PGD) protocols in use produce results after the eggs have been fertilized. However, these approaches are not acceptable for patients with moral objections to the generation and discard of supernumerary zygotes or embryos. In these circumstances, only those oocytes to be replaced may be inseminated. The purpose of this study was to develop a PGD pro...