Preimplantation development directs the formation of an implantation- or attachment-competent embryo so that metabolic interactions with the uterus can occur, pregnancy can be initiated, and fetal development can be sustained. The preimplantation embryo exhibits a form of autonomous development fueled by products provided by the oocyte and also from activation of the embryo's genome. Despite th...

Embryo transfer is a multi-step process that involves the production and collection of preimplantation embryos from genetically superior females (called donors) and the subsequent transfer of the harvested embryos into reproductively healthy females (called recipients) for the purpose of establishing pregnancies and producing live offspring. The first successful embryo transfer in mammals was p...

OBJECTIVE To report the outcomes of more than 100 cycles of preimplantation genetic diagnosis for monogenetic diseases. DESIGN Case series. SETTING Tertiary assisted reproductive centre in Hong Kong, where patients needed to pay for the cost of preimplantation genetic diagnosis on top of standard in-vitro fertilisation charges. PATIENTS Patients undergoing preimplantation genetic diagnosi...

UNLABELLED BACKGROUNDS Previous studies suggested that endocrine disruptors (ED) are toxic on preimplantation embryos and inhibit development of embryos in vitro culture. However, information about the toxicity of endocrine disruptors on preimplantation development of embryo in human reproductive environment is lacking. METHODS Bisphenol A (BPA) and Aroclor 1254 (polychlorinated biphenyls)...

The last three decades have seen considerable progress in the development of culture media for ART and infertility treatment. Basic research on the metabolism of mammalian preimplantation embryos demonstrated the specific needs in the evolving stage of the embryo growing in vitro. Two different philosophies led to two different culture strategies for human preimplantation embryos: the 'back-to-...

To further optimize the culturing of preimplantation embryos, we undertook metabolomic analysis of relevant culture media using capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS). We detected 28 metabolites: 23 embryo-excreted metabolites including 16 amino acids and 5 media-derived metabolites (e.g., octanoate, a medium-chain fatty acid (MCFA)). Due to the lack of informatio...

Paraquat can cause oxidative stress through redox cycling, and preimplantation embryos are sensitive to oxidative stress in vitro. In this study, the effects of paraquat on preimplantation embryo development were examined. Exposure of preimplantation embryos (collected on the day after ovulation) to paraquat in vitro for 24 h at concentrations as low as 8 microM caused a significant decrease in...

Preimplantation development of the mammalian embryo consists of stages that include formation of the zygote, blastocyst formation and implantation of the embryo into the uterus. Depending on the animal, first few cleavages of the early embryo is fully supported by translation of maternal transcripts and use of maternal proteins. After this period, the preimplantation embryo starts to transcribe...

Preimplantation embryo development involves four stages: fertilization, cell cleavage, morula and blastocyst formation. During these stages, maternal and zygotic epigenetic factors play crucial roles. The gene expression profile is changed dramatically, chromatin is modified and core histone elements undergo significant changes. Each preimplantation embryo stage has its own characteristic epige...

The cells in the preimplantation mammalian embryo undergo several rounds of fast cell division. Whether the known DNA repair pathways are active during these early stages of development where cell division is of primary importance, has not been fully established. Because of the important role of phosphorylated H2A.X (gammaH2A.X) in the DNA damage response as well as its putative role in assembl...