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Women, assisted reproduction and the “natural”
Published in Wendy A. Rogers, Jackie Leach Scully, Stacy M. Carter, Vikki A. Entwistle, Catherine Mills, The Routledge Handbook of Feminist Bioethics, 2022
Two MRT techniques have been the subject of research in the United Kingdom – maternal spindle transfer (MST) and pronuclear transfer (PNT): MST involves transferring a spindle-shaped group of maternal chromosomes from a woman’s pre-fertilized egg to a donor egg with healthy mitochondria, from which the donor’s chromosomes have been removed; PNT involves transferring the pro-nuclei (nuclear material) from a couple’s newly fertilized egg that has unhealthy mitochondria into a donated embryo, with healthy mitochondria, that has had its own, original pro-nuclei removed (DH 2014).
Embryo Kinetics and Aneuploidy
Published in Carlos Simón, Carmen Rubio, Handbook of Genetic Diagnostic Technologies in Reproductive Medicine, 2022
Fernando Meseguer, Noelia Ramírez, Marcos Meseguer
The first embryonic development event that occurs and can be evaluated in IVF treatments is the appearance of the pronuclei. A human oocyte successfully fertilized contains two pronuclei and two polar bodies (78). It is widely accepted that mono- and tri-pronuclear embryos can also continue development to the blastocyst stage, but they are likely to be aneuploid. The time of pronuclei fading (tPNf) is an early morphokinetic parameter which can also predict clinical outcomes. While some authors did not find direct association between tPNf and aneuploidies assessed by TE biopsy and 24 chromosome-microarrays (79), others showed that the mean duration of pronuclei fading (tPNf) for normal embryos was significantly shorter than in abnormal ones (80–82). Other studies showed that the morphokinetic parameters most related to ploidy were the pronuclei duration (dPN = tPNf – tPNa) and the onset of the first cytokinesis, which were longer in aneuploid embryos compared to euploid embryos (83,84). Nonetheless, time of pronuclei appearance and time for second polar body extrusion were not significantly different between normal and abnormal embryos (80).
Regulation of Reproduction by Dopamine
Published in Nira Ben-Jonathan, Dopamine, 2020
The oocyte, which because of ovulation has been arrested in metaphase of meiosis II, responds to sperm entry by completing meiosis. This leads to an unequal division of the cytoplasm and the generation of a large ovum, and a very small second cell, the polar body. The egg now includes two haploid nuclei, referred to as pronuclei, that are derived from the sperm and oocyte (Figure 10.15). The pronuclei decondense, expand, and replicate their DNA. Upon migration toward each other, the nuclear envelopes of the pronuclei disintegrate, and male- and female-derived genetic material intermingles. This step completes the process of fertilization, yielding a single-celled, diploid zygote endowed with all the genetic instructions needed for developing into a human being.
Comparison the effects of progestin-primed ovarian stimulation (PPOS) protocol and GnRH-a long protocol in patients with normal ovarian reserve function
Published in Gynecological Endocrinology, 2023
Shaoyuan Xu, Xiaoning Wang, Ying Zhang, Yifan Han, Changjun Zhang
The oocytes were cultured after conventional in vitro fertilization. 16 ∼ 18 h later the pronucleus was observed, appearance of two pronucleus was judged as normal fertilization. The embryo scoring method on the 3rd day after oocytes retrieval was referred to Ziebe, etc [8]. Grade I ∼ II are high-quality embryos; Grade I ∼ III is usable embryo; Grade IV embryos are discarded embryos. From the day of oocytes retrieving, 90 mg/d of vaginal progesterone vaginal sustained-release gel (Merck Serono, Switzerland) and 20 mg/d of oral dydrogesterone (Solvay Pharma, Netherlands) were used for luteal support. All the embryo in PPOS group were frozen. After the second normal menstrual cycle, the endometrium was prepared by hormone replacement protocol, and Luteal support was performed as the same as that in fresh embryos transferring.
Fertilisation and early embryonic development of immature and rescue in vitro-matured sibling oocytes
Published in Human Fertility, 2022
Berrin Avci, Isil Kasapoglu, Cihan Cakir, Aysun Ozbay, Baris Ata, Gurkan Uncu
In routine practice, oocytes at GV and MI stages in groups 1 and 2 were kept in the fertilisation medium for overnight incubation after fertilisation. Utilising fertilisation medium allowed the possibility of spontaneous maturation of the oocytes selectively, whereas use of maturation medium might stimulate in vitro maturation of the immature oocytes. After incubation for 18–24 hours, ICSI was performed on oocytes which had reached the metaphase II stage from the GV phase (Group 1, n = 104) and oocytes that reached the metaphase II stage from the MI stage (Group 2, n = 231) (1 day after follicular aspiration). Immediate intracytoplasmic sperm injection was carried out on the day of follicle aspiration on the MI oocytes in Group 3 (n = 292) and on mature oocytes which were at the MII stage on oocyte aspiration day (Group 4, n = 1798). All oocytes that had reached the metaphase II stage by the end of the workday were included in Group 4. Oocytes were re-evaluated 16–18 hours after microinjection with an inverted microscope (Nikon Eclipse TE-2000-U, JAPAN). The presence of male and female pronuclei (PN) was used to confirm successful fertilisation, whereas detection of one or three pronuclei was classified as abnormal fertilisation. Post-ICSI degeneration of oocytes was also noted. Embryo cleavage was evaluated 24 hours after the detection of the pronuclei. Following fertilisation, embryos were cultured for a period of 6 days. Embryo transfer was performed on day 3 and day 5. The number of embryos reaching the blastocyst stage of development at day 5 and day 6 in culture was recorded.
Kallistatin in follicular fluid of women with endometriosis and its correlation with IVF outcome
Published in Gynecological Endocrinology, 2021
Yuling Mao, Shaoquan Zhan, JingDa Qiao, Lei Li, Hanyan Liu, Rui Chen
Women were monitored and managed according to the hospital’s clinical protocols. Various controlled ovarian stimulation (COS) protocols were used, with 150–450 IU/d of recombinant FSH or human menopausal gonadotropin in a gonadotropin-releasing hormone antagonist protocol, a long agonist protocol, or a short agonist protocol. The protocols were determined according to each patient's characteristics (age, body mass index [BMI], AFC, and AMH). Transvaginal oocyte retrieval was scheduled 35–36 h after hCG injection ART was performed per standard operating procedure of the hospital. Fertilization was assessed by the appearance of two pronuclei. Cleavage stage embryos were graded as per the Istanbul consensus. Fresh embryo transfer (ET) was performed 2–3 or 5 d later. Embryos were vitrified frozen on day 3, 5, or 6. The luteal phase was supported by vaginal administration of micronized progesterone (P) (400 mg/d) started on the day of ovarian puncture.