Meiotic and mitotic behaviour of a ring/deleted chromosome 22 in human embryos determined by preimplantation genetic diagnosis for a maternal carrier

<p>Abstract</p> <p>Background</p> <p>Ring chromosomes are normally associated with developmental anomalies and are rarely inherited. An exception to this rule is provided by deletion/ring cases. We were provided with a unique opportunity to investigate the meiotic segregation at oogenesis in a woman who is a carrier of a deleted/ring 22 chromosome. The couple requested preimplantation genetic diagnosis (PGD) following the birth of a son with a mosaic karyotype.</p> <p>The couple underwent two cycles of PGD. Studies were performed on lymphocytes, single embryonic cells removed from 3 day-old embryos and un-transferred embryos. Analysis was carried out using fluorescence in situ hybridisation (FISH) with specific probe sets in two rounds of hybridization.</p> <p>Results</p> <p>In total, 12 embryos were biopsied, and follow up information was obtained for 10 embryos. No embryos were completely normal or balanced for chromosome 22 by day 5. There was only one embryo diagnosed as balanced of 12 biopsied but that accumulated postzygotic errors by day 5. Three oocytes apparently had a balanced chromosome 22 complement but all had the deleted and the ring 22 and not the intact chromosome 22. After fertilisation all the embryos accumulated postzygotic errors for chromosome 22.</p> <p>Conclusion</p> <p>The study of the preimplantation embryos in this case provided a rare and significant chance to study and understand the phenomena associated with this unusual type of anomaly during meiosis and in the earliest stages of development. It is the first reported PGD attempt for a ring chromosome abnormality.</p

Male and female meiotic behaviour of an intrachromosomal insertion determined by preimplantation genetic diagnosis

<p>Abstract</p> <p>Background</p> <p>Two related family members, a female and a male balanced carrier of an intrachromosomal insertion on chromosome 7 were referred to our centre for preimplantation genetic diagnosis. This presented a rare opportunity to investigate the behaviour of the insertion chromosome during meiosis in two related carriers. The aim of this study was to carry out a detailed genetic analysis of the preimplantation embryos that were generated from the three treatment cycles for the male and two for the female carrier.</p> <p>Patients underwent <it>in vitro </it>fertilization and on day 3, 22 embryos from the female carrier and 19 embryos from the male carrier were biopsied and cells analysed by fluorescent in situ hybridization. Follow up analysis of 29 untransferred embryos was also performed for confirmation of the diagnosis and to obtain information on meiotic and mitotic outcome.</p> <p>Results</p> <p>In this study, the female carrier produced more than twice as many chromosomally balanced embryos as the male (76.5% vs. 36%), and two pregnancies were achieved for her. Follow up analysis showed that the male carrier had produced more highly abnormal embryos than the female (25% and 15% respectively) and no pregnancies occurred for the male carrier and his partner.</p> <p>Conclusion</p> <p>This study compares how an intrachromosomal insertion has behaved in the meiotic and preimplantation stages of development in sibling male and female carriers. It confirms that PGD is an appropriate treatment in such cases. Reasons for the differing outcome for the two carriers are discussed.</p

Combining 3D surveying with archaeological uncertainty: the metopes of the Athenian Treasury at Delphi

Summarization: At the archaeological site of Delphi, significant monuments inherently communicate uncertainty regarding the reconstruction of their initial form. An innovative, preliminary, theoretical formulation of a 3D visualization system is proposed, combining 3D surveying based on terrestrial laser scanning and archaeological uncertainty which, unlike past work, will offer multiple hypotheses to be visualized. The system, when implemented, will take as input the archaeologists’ assessment regarding various evidence and offers probabilistic reasoning in relation to the monuments’ past form, which is finally reconstructed and visualized in 3D. The positioning of the metopes of the Athenian Treasury at Delphi is presented as a case study.Παρουσιάστηκε στο: 2021 12th International Conference on Information, Intelligence, Systems & Application

European women in neurosurgery: II - Historical characters and living legends

A collaborative global working group of women neurosurgeons in multiple countries at different stages of their neurosurgical careers undertook the task of researching the history of European women in neurosurgery. While doing so, we happened upon many remarkable female neurosurgeons who overcame great adversity, made tremendous contributions to society and institutional neurosurgery, and displayed numerous talents beyond the operating room. In the first part of this paper, we recounted a chronology of female neurosurgeons in Europe, highlighting the most remarkable achievements of women in every decade, from the 1920's to 2020. In this paper, we honor fascinating women in European neurosurgery, both historical characters and living legends. These women have overcome great adversity and have also excelled in a huge variety of pursuits. While some were themselves refugees, we also have uncovered noteworthy examples of women who immersed themselves in humanitarian missions and who tried to better the world through political action. There are stories of women beating the odds, taking on biased institutions and proving their worth, in spite of the prevailing system. Most inspirational, we have discovered through our comprehensive research on the history of women in European neurosurgery that the future is increasingly female

European women in neurosurgery: I - A chronology of trailblazers

Neurosurgery as a distinct speciality has been around for 100 years. Some of the earliest women neurosurgeons were European, emerging from the 1920's onwards. Here we detail the rise of women in neurosurgery across Europe with a decade by decade account of big events and firsts across the continent. The emerging themes are seen in stories of pioneers with enormous resilience, camaraderie, trailblazing and triumphing in a system with great obstacles and challenges. Our journey through this chronology brings us to the modern day, where most European countries have or have had a woman neurosurgeon and the future for women in neurosurgery in the continent is very bright

Distinct pathways drive anterior hypoblast specification in the implanting human embryo.

Development requires coordinated interactions between the epiblast, which generates the embryo proper; the trophectoderm, which generates the placenta; and the hypoblast, which forms both the anterior signalling centre and the yolk sac. These interactions remain poorly understood in human embryogenesis because mechanistic studies have only recently become possible. Here we examine signalling interactions post-implantation using human embryos and stem cell models of the epiblast and hypoblast. We find anterior hypoblast specification is NODAL dependent, as in the mouse. However, while BMP inhibits anterior signalling centre specification in the mouse, it is essential for its maintenance in human. We also find contrasting requirements for BMP in the naive pre-implantation epiblast of mouse and human embryos. Finally, we show that NOTCH signalling is important for human epiblast survival. Our findings of conserved and species-specific factors that drive these early stages of embryonic development highlight the strengths of comparative species studies.Open Atlas NOMIS Gates Cambridge Trust Leverhulme Trust Rosetrees Trus

Distinct pathways drive anterior hypoblast specification in the implanting human embryo.

Acknowledgements: The authors thank patients at CARE, Herts & Essex, Bourn Hall Fertility and King’s Fertility Clinics for their generous donations, as well as the embryologists and members of each clinic for facilitating donations. We thank G. Serapio-García for advice on Bayesian statistical analysis and the bioinformaticians and data scientists who made their code, packages and vignettes available. This work is supported by Wellcome Trust (207415/Z/17/Z) and Open Atlas and NOMIS awards to M.Z.-G. B.A.T.W. was supported by the Gates Cambridge Trust. C.W.G. was supported by a Leverhulme Trust Early Career Fellowship. L.K.I.-S. was supported by the Rosetrees Trust.Funder: NOMIS Stiftung (NOMIS Foundation); doi: https://doi.org/10.13039/501100008483Funder: Open AtlasFunder: Gates Cambridge Trust; doi: https://doi.org/10.13039/501100005370Funder: Leverhulme Trust; doi: https://doi.org/10.13039/501100000275Funder: Rosetrees Trust; doi: https://doi.org/10.13039/501100000833Development requires coordinated interactions between the epiblast, which generates the embryo proper; the trophectoderm, which generates the placenta; and the hypoblast, which forms both the anterior signalling centre and the yolk sac. These interactions remain poorly understood in human embryogenesis because mechanistic studies have only recently become possible. Here we examine signalling interactions post-implantation using human embryos and stem cell models of the epiblast and hypoblast. We find anterior hypoblast specification is NODAL dependent, as in the mouse. However, while BMP inhibits anterior signalling centre specification in the mouse, it is essential for its maintenance in human. We also find contrasting requirements for BMP in the naive pre-implantation epiblast of mouse and human embryos. Finally, we show that NOTCH signalling is important for human epiblast survival. Our findings of conserved and species-specific factors that drive these early stages of embryonic development highlight the strengths of comparative species studies.Open Atlas NOMIS Gates Cambridge Trust Leverhulme Trust Rosetrees Trus