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Fertilization and normal embryonic and early fetal development
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Asim Kurjak, Ritsuko K. Pooh, Aida Salihagic-Kadic, Iva Lausin, Lara Spalldi-Barisic
Already few minutes after the ovulation, oocyte is located in the ampullar part of the fallopian tube. It is surrounded by the zona pellucida. On the surface of the zona pellucida, there are few rows of the granulosa cells that make corona radiata. At the periphery of the corona radiata are left cells of cumulus oophorus. Often, these three units are called oocyte–corona–cumulus complex. Capability for the fertilization is limited: oocyte can be fertilized only 6 to 12 hours after the ovulation. Sperms are capable for fertilization 48 to 72 hours, until they are movable. Fertilization occurs in the ampullar part of the fallopian tube. The process of fertilization begins with conditioning of the spermatozoon in the male and female reproductive tracts. Thereafter, fertilization involves not only the egg itself but also the various investments that surround the egg at the time it is released from the ovary follicle. Fertilization, therefore, is not an event; it is a complex biochemical process requiring a minimum of 24 hours to complete syngamy (formation of a diploid set of chromosomes). During that process, there is no commingling of maternal and paternal chromosomes within a single nuclear membrane (pre-zygote); after this process, the paternal chromosome material is commingled (zygote). The most important activity of this new cell is the recognition of the new genome that presents the principal information center for the development of the human being and for all its further activities.
Ovarian Ectopic Pregnancy
Published in Botros Rizk, A. Mostafa Borahay, Abdel Maguid Ramzy, Clinical Diagnosis and Management of Gynecologic Emergencies, 2020
Ninety five percent of ectopic pregnancies are tubal, with the remaining 5% located in the ovary, the abdomen, the cervix, or a cesarean scar [1, 2]. Primary ovarian ectopic pregnancy is rare; its incidence ranges from one in 2100 to one in 600,000 pregnancies. Since the first case reported by Saint Maurice of France in 1682, the incidence of ovarian ectopic pregnancy has been increasing [3]. The ovarian ectopic pregnancy rate as a percentage of all ectopic pregnancies varies from 0.95% to 6.0%. Although ovarian ectopic pregnancies are rare, the potential for serious morbidity and mortality remains high, with a high rate of circulatory collapse and hemoperitoneum due to rupture [4, 5]. The reported incidence of ovarian pregnancy is growing because of the evolution of transvaginal sonography and careful histologic examination of the ovarian tissues [6]. Interestingly, ovarian pregnancy has been reported following in vitro fertilization [7].
The many revolutions of the 20th century
Published in Nadia Maria Filippini, Clelia Boscolo, Pregnancy, Delivery, Childbirth, 2020
It is important to emphasise that artificial insemination, especially after IVF (in vitro fertilisation and embryo transfer), triggered a real social and cultural earthquake within the family, motherhood and in the very representation of birth.
Ethics Considerations Regarding Artificial Womb Technology for the Fetonate
Published in The American Journal of Bioethics, 2023
Felix R. De Bie, Sarah D. Kim, Sourav K. Bose, Pamela Nathanson, Emily A. Partridge, Alan W. Flake, Chris Feudtner
Fertilization of a human egg outside of the maternal body and subsequent successful implantation was first performed in 1978 in the United Kingdom, resulting in the birth of the famous “test tube baby” Louise Brown (Steptoe and Edwards 1978). In vitro fertilization (IVF) since then has become the cornerstone of assisted reproductive technologies, which in the United States in 2018 was involved in 1.9% of births according to data available from the Centers for Disease Control and Prevention (CDC 2018). Upon fertilization, the zygote is typically cultured for three to five days before it is implanted in the womb to become an embryo. In an experimental setting however, continued research efforts have led to optimization of culture conditions allowing human embryo culture until 14days conceptional age (CA)(Deglincerti et al. 2016; Shahbazi et al. 2016). In most jurisdictions, legal restrictions prohibit the culture of human embryos beyond 14days of development (Pera 2017). Although the authors of this experimental work invoke these legal reasons for not going beyond the two-week hallmark, their work and findings have been used to advocate for an extension of these legal and moral limitations (Morris 2017). In 2021, the International Society for Stem Cell Research (ISSCR) updated their guidelines, recommending that studies proposing to grow human embryos beyond the two-week mark be considered on a case-by-case basis, and be subjected to several phases of review to determine at what point the experiments must be stopped (ISCCR 2021; Subbaraman 2021).
Sildenafil aggravates adriamycin-induced testicular toxicity in rats; a preliminary investigation
Published in Drug and Chemical Toxicology, 2023
Anne A. Adeyanju, Omolola R. Oyenihi, Oluwafemi O. Oguntibeju, Oreoluwa Ojomu
The cells of the reproductive system are one of the cells most affected by ADR treatment due to the rapidly proliferating characteristic of these cells similar to tumor cells (Prieto-Callejero et al.2020). Studies have reported the induction of testicular toxicity in rats by the intraperitoneal injection of a single dose of ADR (20 mg/kg) (Saalu et al.2010, Molehin et al.2018). The manifestation of testicular toxicity was assessed via analysis of sperm function: sperm count, motility, sperm viability, and morphological abnormalities (Hukkanen et al.2016). Evidence from previous studies indicates that sperm motility is an important factor in the success of fertilization, and any negative impact of motility would cause adverse effects on the fertilization capacity (Kumar and Singh 2015, Peiris et al.2015). ADR induced testicular toxicity in rats evident by a significant reduction in sperm count (99.40 ± 16.12 × 106/ml in ADR-treated rats versus 135 ± 13.52 × 106/ml in the vehicle control) and sperm motility (70 ± 7.07% in ADR-treated rats versus 85 ± 7.07% in the vehicle control) indicating a negative effect on reproductive health.
Trophectoderm non-coding RNAs reflect the higher metabolic and more invasive properties of young maternal age blastocysts
Published in Systems Biology in Reproductive Medicine, 2023
Panagiotis Ntostis, Grace Swanson, Georgia Kokkali, David Iles, John Huntriss, Agni Pantou, Maria Tzetis, Konstantinos Pantos, Helen M. Picton, Stephen A. Krawetz, David Miller
Blastocyst implantation is a highly complex process relying on close coordination between the attaching embryo and the receptive endometrium, with approximately 50% of good quality blastocysts failing to implant (Craciunas et al. 2019). Human blastocyst formation occurs while the developing zygote is transiting through the fallopian tube, normally reaching the uterine cavity on the 5th day after successful fertilization (Norwitz et al. 2001; Figure 1). Embryo-endometrial communication supported by various cell surface and secreted factors is thought to take place at the blastocyst stage, preparing the embryo for initial adhesion and attachment (Simón et al. 2000; Ashary et al. 2018). Implantation itself follows the firm attachment of the embryo to the endometrium’s luminal epithelium.