59 research outputs found
Insulin increases epiblast cell number of in vitro cultured mouse embryos via the PI3K/GSK3/p53 pathway
High-quality embryos give rise to embryonic stem cells (ESCs) at greater efficiencies than poor-quality embryos. However, most embryos available for human ESC derivation are of a reduced quality as a result of culture in relatively simple media up to 10 years earlier, before cryopreservation, or before compaction. In the present study, we used a mouse model to determine whether a culture with insulin from the 8-cell stage could increase the number of ESC progenitor epiblast cells in blastocysts, as well as endeavor to determine the molecular mechanism of the insulin's effect. Culture in media containing 1.7âÏM insulin increased epiblast cell number (determined by Oct4 and Nanog co-expression), and proportion in day 6 blastocysts. The inhibition of phosphoinositide 3 kinase (PI3K) (via LY294002), an early second messenger of the insulin receptor, blocked this effect. The inhibition of glycogen synthase kinase 3 (GSK3) or p53, 2âs messengers inactivated by insulin signaling (via CT99021 or pifithrin-α, respectively), increased epiblast cell numbers. When active, GSK3 and p53 block the transcription of Nanog, which is important for maintaining pluripotency. A simultaneous inhibition of GSK3 and p53 had no synergistic effects on epiblast cell number. The induced activation of GSK3 and p53, via the inhibition of proteins responsible for their inactivation (PKA via H-89 and SIRT-1 via nicotinamide, respectively), blocked the insulin's effect on the epiblast.From our findings, we conclude that insulin increases epiblast cell number via the activation of PI3K, which ultimately inactivates GSK3 and p53. Furthermore, we suggest that the inclusion of insulin in culture media could be used as a strategy for increasing the efficiency with which the ESC lines can be derived from cultured embryos.Jared M. Campbell, Mark B. Nottle, Ivan Vassiliev, Megan Mitchell, and Michelle Lan
First-time mothersâ experiences of pregnancy and birth following assisted reproductive technology treatment in Taiwan
Background
Assisted Reproductive Technology (ART) treatment tends to involve significant physical and emotional commitments that can impact maternal, infant and family health and well-being. An in-depth understanding of experiences is necessary to provide adequate support for women and their families during pregnancy and transition to parenthood following ART treatment. The aim of this study was to explore first-time mothersâ experiences of pregnancy and transition to parenthood following successful ART treatment in Taiwan.
Method
Twelve first-time mothers who conceived and gave live birth using ART treatment were purposively selected from a fertility centre in Taipei, Taiwan. Womenâs experiences in pregnancy and in their transition to motherhood were explored using semi-structured in-depth interviews. All interviews were recorded, transcribed, and analysed using the Colaizzi strategy.
Results
The mothersâ accounts reflected three main themes: âbeing different from mothers who became pregnant naturallyâ; âensuring health and safety of the foetusâ; and âwelcoming new lives with excitementâ. The difference mothers felt about themselves was evident in four subthemes: becoming pregnant after a long wait, feeling vulnerable during pregnancy, relying on familyâs assistance and support, and worrying about the impact of ART on health. The theme on âensuring health and safety of the foetusâ encompassed three subthemes: activities to protect the unborn baby, monitoring foetal movement constantly to maintain peace of mind, and receiving foetal reduction for the sake of the pregnancy. Narratives around âwelcoming new lives with excitementâ reflected four subthemes: overcoming hardship for worthwhile results, realising oneâs life and dreams, proving to be fertile enough to give birth, and return to normal life track.
Conclusion
Findings indicate the need for educational and psychosocial interventions to support women and their families physically and psychologically during ART treatment. The stigma related to infertility and the psychosocial support from family are aspects to consider while planning intervention programmes
Structural and Sequence Analysis of Imelysin-Like Proteins Implicated in Bacterial Iron Uptake
Imelysin-like proteins define a superfamily of bacterial proteins that are likely involved in iron uptake. Members of this superfamily were previously thought to be peptidases and were included in the MEROPS family M75. We determined the first crystal structures of two remotely related, imelysin-like proteins. The Psychrobacter arcticus structure was determined at 2.15 Ă
resolution and contains the canonical imelysin fold, while higher resolution structures from the gut bacteria Bacteroides ovatus, in two crystal forms (at 1.25 Ă
and 1.44 Ă
resolution), have a circularly permuted topology. Both structures are highly similar to each other despite low sequence similarity and circular permutation. The all-helical structure can be divided into two similar four-helix bundle domains. The overall structure and the GxHxxE motif region differ from known HxxE metallopeptidases, suggesting that imelysin-like proteins are not peptidases. A putative functional site is located at the domain interface. We have now organized the known homologous proteins into a superfamily, which can be separated into four families. These families share a similar functional site, but each has family-specific structural and sequence features. These results indicate that imelysin-like proteins have evolved from a common ancestor, and likely have a conserved function
"One for Sorrow, Two for Joy?": American embryo transfer guideline recommendations, practices and outcomes for gestational surrogate patients
In January 2016, Melissa Cook, a California gestational surrogate experiencing a multiple birth pregnancy following the in vitro fertilization (IVF) transfer of three embryos comprised of donor eggs and sperm provided by the intended father went to the media when the intended father requested that she undergo a fetal reduction because twins were less expensive to raise than triplets. Much of the legal interest in this case to date has centered on the enforceability of surrogacy contracts. However, the Cook case also raises troubling issues about fertility treatment practices involving gestational surrogates, twin preference, and third-party reproduction medical decision-making. This paper focuses on multipleembryo transfers in the context of U.S. surrogacy arrangements. Offering an original analysis of data obtained from the U.S. national assisted reproduction registry, it examines single- and multiple-embryo transfer trends over an eleven-year period (2003 to 2014). Findings reveal that recommended guidelines were followed in less than 42% of cases in 2014. The paper argues that ensuring equitable medical treatment for all recipients of IVF requires the adoption of treatment guidelines tailored to, and offering protections for, specific patient groups, and that, once in place, guidelines must be robustly implemente
Privacy versus disclosure in gamete donation: A clash of interest, of duties, or an exercise in responsibility?
Histopathological Aspects of Neurocryptococcosis in HIV-Infected Patients: Autopsy Report of 45 Patients
Embryo donation at an Australian university inâvitro fertilisation clinic: issues and outcomes
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