319 results on '"A Christodoulaki"'
Search Results
302. Endometrioid ovarian cancer arising from an endometriotic cyst in a young patient.
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Zygouris, D., Leontara, V., Makris, G. M., Chrelias, C., Trakakis, E., Christodoulaki, Ch., and Panagopoulos, P.
- Abstract
The article presents a case of 33-year-old woman diagnosed with ovarian endometrioid adenocarcinoma which arises from an endometriotic cyst. The patient has chronic pelvic pain but did not complain of dysmenorrhea or dyspareunia. Magnetic resonance imaging (MRI) revealed a 6 centimeter (cm) mass in the Douglas pouch after one month of diagnostic laparoscopy. The patient received four cyles of carboplatin/taxol chemotherapy following an exploratory laparotomy which revealed no pathology.
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- 2012
303. Solar-powered hybrid energy storage system with phase change materials.
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Baghaei Oskouei, Seyedmohsen, Frate, Guido Francesco, Christodoulaki, Rosa, Bayer, Özgür, Akmandor, İbrahim Sinan, Desideri, Umberto, Ferrari, Lorenzo, Drosou, Vassiliki, and Tarı, İlker
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ENERGY storage , *PHASE change materials , *HEAT storage , *CLEAN energy , *SOLAR energy , *SOLAR thermal energy - Abstract
• A 25kWh encapsulated LTES is investigated using CFD. • Data from CFD is fed into a scheme to investigate the yearly charging performance. • Performance differs seasonally, with varying temperatures impacting the operation. • Optimization reduces cooling unit heat dissipation and maximizes stored heat. Solar energy's growing role in the green energy landscape underscores the importance of effective energy storage solutions, particularly within concentrated solar power (CSP) systems. Latent thermal energy storage (LTES) and leveraging phase change materials (PCMs) offer promise but face challenges due to low thermal conductivity. This work comprehensively investigates LTES integration into solar-thermal systems, emphasizing medium-temperature applications. It introduces an innovative LTES tank design with encapsulating tubes modeled through computational fluid dynamics (CFD). The system employs a novel hybrid thermal storage approach, enhancing thermal output through a high-temperature heat pump (HTHP) before storage. This approach aligns with future energy systems, emphasizing energy vector integration. The study offers realistic LTES modeling, accounting for natural convection effects, and integrates LTES within solar thermal systems by taking advantage of time dependent CFD results. Real-world solar irradiance data for an Italian city is integrated into the investigation, providing insights into LTES performance and its role in sustainable solar energy solutions. A multi-objective optimization process follows the year-round simulations to maximize the amount of stored heat and minimize the electric input. This approach facilitates better system sizing and performance evaluation, contributing to the advancement of solar thermal technology. [ABSTRACT FROM AUTHOR]
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- 2024
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304. The origins of central banking in Greece
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Christodoulaki, Olga
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- 332.1, HC Economic History and Conditions
- Abstract
The establishment of a fully fledged central bank in Greece between May 1927 and May 1928 was a prerequisite for the country’s stabilisation programme prepared by the FinancialCommittee of the League of Nations. Prior to 1928, the National Bank of Greece had acted as a central bank whilst at the same time being by far the biggest and most powerful commercial bank in the country. Under pressure from the League, its governors faced the challenge of transforming it into a fully fledged central bank by shedding all business that was in the province of deposit and commercial banking. They chose instead for the Bank to retain its commercial activities and instead a new fully fledged central bank was established. This thesis explores both the central banking and commercial aspects of the National Bank from the enactment of the Law of Control in 1898 until de jure stabilisation in 1928. It addresses the following questions: why was the National Bank not in a position to transform itself into a fully fledged central bank on its own initiative following a path similar to that described by the natural evolution hypothesis? Why were the commercial activities of the National Bank so important that in the end it chose to retain that aspect of its business when prior to 1927 it had so fiercely guarded its central banking privileges? It is argued that it was the way in which the governors of the National Bank combined central banking responsibilities with commercial banking that safeguarded and preserved the financial strength and consequently the reputation of the Bank throughout its entire history as a bank of issue. The financial position of the dual-purpose Bank was also protected by the conservative and risk-averse way in which it pursued its commercial activities. The National Bank’s financial strength was based on its market power and its ability to select high quality assets and liabilities which resulted in its enduring profitability and solvency. The quality of its assets and liabilities was more important for its governors than maximisation of profits per se. The way that central banking reforms were implemented is also studied. The objectives and functions of the new central bank are evaluated as well as its financial position when it first opened its doors for business. It is maintained that the statutes of the Bank of Greece were at the heart of the central banking principles promoted by the Bank of England and were focused on the macro function of a central bank and on its role as the bank of the government. This thesis also sheds light on the complex relationship that arose between Greek governments and foreign supervisors between the enactment of the Law of Control in 1898 and stabilisation in 1928. Furthermore, it asks questions about the conditionality attached to bailout loans in the late nineteenth century and in the 1920s. The impact that international financial intervention had on monetary reforms is clearly demonstrated. It is argued that monetary developments in Greece between 1898 and 1928 reflect the political economy of the time as well as the historical circumstances. Monetary reforms were shaped by the objectives of the National Bank and the constraints under which it operated rather than foreign control. These findings provide valuable insights into why Greek governments have unsuccessfully struggled to implement widespread structural reforms demanded by their lenders since 2010 and as a consequence the country has experienced a deep and protracted economic recession.
- Published
- 2015
305. N2/175 – Aspects of ancient greek philosophers on respiratory tract.
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Christodoulaki, Maria, Kalloniatou, Marianthi, Kanitsakis, Aristidis, Tsoukalas, Grigorios, Xidaki, Evagelia, Kotta, Areti, Koupmoulis, Emmanouel, Daoukakis, Emmanouel, and Tsoukalas, Ioannis
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- 2006
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306. B9/210 – Tuberculosis according to hippocrates.
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Christodoulaki, M., Moschaki, G., Kalloniatou, M., Tsoukalas, G., Kanitsakis, A., Athanasopoulos, D., Blazaki, S., Fiotaki, S., and Tsoukalas, I.
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- 2006
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307. B4/212 – Infections of the lower respiratory system according to hippocrates.
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Christodoulaki, M., Moschaki, G., Kalloniatou, M., Blazaki, S., Tsoukalas, G., Fiotaki, S., Kanitsakis, A., Balomenaki, E., and Tsoukalas, I.
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- 2006
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308. "Maternal diabetes mellitus and its impact on the risk of delivering a child with congenital heart disease: a systematic review and meta-analysis".
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Papazoglou, Andreas S., Moysidis, Dimitrios V., Panagopoulos, Periklis, Kaklamanos, Eleftherios G., Tsagkaris, Christos, Vouloagkas, Ioannis, Karagiannidis, Efstratios, Tagarakis, Georgios I., Papamitsou, Theodora, Papanikolaou, Ioannis G., Christodoulaki, Chryssi, and Vrachnis, Nikolaos
- Abstract
Aim: Maternal pregestational diabetes mellitus (PGDM), type 1 or type 2, has been established as a potential risk factor for congenital heart disease (CHD). At the same time, the correlation between gestational diabetes mellitus (GDM) and increased risk of CHD has not been yet fully elucidated. The objective of this systematic review and meta-analysis (PROSPERO number: CRD42020182390) was to analyze the existing evidence on PGDM and to attempt to fill, to the best of our ability, the remaining knowledge gap in the association of GDM with CHD. Materials and methods: Two authors have independently searched the Pubmed/Medline, Scopus, Cochrane, Web of Science, and Theses Global databases with keywords and Boolean operators. The search yielded 9333 relevant articles, which were later screened for eligibility. Original peer-reviewed (case-control or cohort) studies were included if they were published in English between 1997 and 2020. Thirteen studies on mothers with PGDM and seven studies on mothers with GDM were finally included in our meta-analysis to investigate the association of maternal diabetes with the risk of delivering a child with CHD. The selected studies were all assessed for their methodological quality using the Newcastle–Ottawa scale. Associations with p <.05 were considered statistically significant. Results: Our meta-analysis (I2 > 75%, total population: n = 12,461,586) of 79,476 women with PGDM and 160,893 with GDM produced an odds ratio of 3.48 (2.36–4.61) and 1.55 (1.48–1.61), respectively. Additionally, we did not find any noticeable difference in the risk for CHD among diabetic women living in the USA and Europe. Nevertheless, it still needs to be clarified, whether or not the gestational diabetic population includes undiagnosed women with preexisting diabetes, which might account for the increased risk of delivering a child with CHD in women classified as suffering from GDM. Conclusion: While both GDM and PGDM seem to significantly increase the risk of CHD in comparison with the general population, PDGM appears to have a greater association with CHD, being correlated with a 3.5-fold increase in the risk of malformation. Preconceptional and gestational diabetes care are, therefore, essential to mitigate the adverse effect of hyperglycemia on fetal heart formation during pregnancy. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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309. Phthalates and fetal growth velocity: tracking down the suspected links.
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Vrachnis, Nikolaos, Loukas, Nikolaos, Vrachnis, Dionysios, Antonakopoulos, Nikolaos, Christodoulaki, Chryssi, Tsonis, Orestis, George, Mastorakos, and Iliodromiti, Zoi
- Abstract
Fetuses that have not achieved their full growth potential are associated with adverse perinatal and long-term outcomes; thus, it is essential to identify environmental factors that can potentially impair normal intrauterine development. Endocrine disrupting compounds (EDCs), substances capable of altering the homeostasis of the endocrine system, are thought to play a role in restriction of growth velocity, with phthalates being among the most common EDCs to which pregnant women are exposed. Such exposure can potentially lead to changes to the epigenome, placental structure, and hormone function and trigger oxidative stress. Given that these pathways have been linked to fetal growth restriction, we reviewed the literature on the relationship between phthalates and fetal growth. The majority of the studies, which used birth weight as an indicator of intrauterine development, showed contradictory results, the main reason being the EDCs' rapid metabolism. However, we can draw more consistent conclusions when phthalates are quantified at more than one time point during pregnancy. In this narrative review, we present current data indicating the role of phthalates, and especially di-(2-ethylhexyl) phthalate (DEHP), in abnormal fetal growth velocity. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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310. Migration and newborn screening: time to build on the European Asylum, Integration and Migration Fund?
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Tsagkaris, Christos, Eleftheriades, Anna, Moysidis, Dimitrios V., Papazoglou, Andreas S., Loudovikou, Anna, Panagiotopoulos, Dimitrios, Christodoulaki, Chrysi, and Panagopoulos, Periklis
- Abstract
The authors discuss the need for newborn screening in the context of the migration policy of the European Union, and particularly, the European Asylum, Migration and Integration Fund. The authors searched scholarly databases (Pubmed, Scopus, Google scholar) and grey literature (LexEuropa, Policy reports) to identify original peer-reviewed research examining the migration to the European Union and the provision of healthcare to infants born to refugees and immigrant mothers. Resources in language different from English, French, German and Greek were not taken into consideration. Every year, a large number of refugees and immigrants from sub-Saharan Africa and Middle East countries travel to and enter in Europe. It has been estimated that two thirds of those seeking asylum are women and children. Many of these children have been born on the way to Europe or in migrant camps. Essential newborns' health screening is not accessible in most cases. Congenital conditions such as hypothyroidism and phenylketonuria may remain untreated, and once these infants are diagnosed, the organic damage could be irreversible. Prolonged necessary hospitalisation might be out of consideration at a time when clinics and hospitals are overstrained with COVID-19 patients. It is essential to ensure that newborn screening will be performed in a timely and evidence-based manner as well as that the information will be communicated between hospitals and within countries' health networks. In order to achieve these goals interdisciplinary and international technical and logistical collaboration are required. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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311. Polycystic Ovary Syndrome Triggers Atrial Conduction Disorders: A Systematic Review and Meta-Analysis.
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Moysidis, Dimitrios V., Papazoglou, Andreas S., Tsagkaris, Christos, Oikonomou, Vasileios, Loudovikou, Anna, Kartas, Anastasios, Stalikas, Nikolaos, Karagiannidis, Efstratios, Găman, Mihnea-Alexandru, Papadakis, Marios, Christodoulaki, Chrysi, and Panagopoulos, Periklis
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POLYCYSTIC ovary syndrome , *ATRIAL flutter , *P-waves (Electrocardiography) , *CARDIOLOGICAL manifestations of general diseases , *ATRIAL fibrillation - Abstract
Background: Polycystic ovary syndrome (PCOS) is closely related to various adverse cardiovascular manifestations and increased cardiovascular risk. However, atrial fibrillation (AF) development and atrial conduction abnormalities have not been thoroughly studied in patients with PCOS. Methods: This meta-analysis (CRD42021261375) was conducted in accordance with the PRISMA guidelines. Our aim was to investigate associations between PCOS and disorders in atrial conduction parameters linked with an increased risk for AF occurrence. Results: Five cohort studies with aggregate data on 406 adult women (229 with PCOS and 177 age-matched without PCOS) were included in this analysis. Our results showed a significantly increased mean difference in P-wave maximum duration (+7.63 ± 7.07 msec; p < 0.01) and P-wave dispersion (+11.42 ± 5.22 msec; p = 0.03) of patients with PCOS compared to healthy women. The mean difference in P-wave minimum duration (−2.22 ± 2.68 msec; p = 0.11) did not reach the statistical threshold between the compared groups. Echocardiographic measurements of atrial electromechanical delay (AED) also indicated a statistically significant mean difference in favour of the PCOS group in all assessed parameters, except for atrial electromechanical coupling (PA) in the tricuspid annulus. Particularly, PCOS was associated with increased lateral PA, septal PA, inter- and intra-AED durations (mean difference: +17.31 ± 9.02 msec; p < 0.01, +11.63 ± 7.42 msec; p < 0.01, +15.31 ± 9.18 msec; p < 0.01, +9.31 ± 6.85 msec; p < 0.01, respectively). Conclusions: PCOS is strongly associated with alterations in several electrocardiographic and echocardiographic parameters indicating abnormal atrial conduction. Therefore, PCOS could be considered as a causal or triggering factor of AF. Larger studies are needed to confirm these results and investigate direct associations between PCOS and AF. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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312. Human germline nuclear transfer to overcome mitochondrial disease and failed fertilization after ICSI.
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Tang, Maoxing, Boel, Annekatrien, Castelluccio, Noemi, Cardona Barberán, Arantxa, Christodoulaki, Antonia, Bekaert, Bieke, Popovic, Mina, Vanden Meerschaut, Frauke, De Sutter, Petra, Menten, Björn, Symoens, Sofie, Vanlander, Arnaud V., Stoop, Dominic, Coucke, Paul J., and Heindryckx, Björn
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GERM cells , *INTRACYTOPLASMIC sperm injection , *MITOCHONDRIA , *MITOCHONDRIAL DNA , *INFECTIOUS disease transmission , *GENETIC testing - Abstract
Purpose: Providing additional insights on the efficacy of human nuclear transfer (NT). Here, and earlier, NT has been applied to minimize transmission risk of mitochondrial DNA (mtDNA) diseases. NT has also been proposed for treating infertility, but it is still unclear which infertility indications would benefit. In this work, we therefore additionally assess the applicability of NT to overcome failed fertilization. Methods: Patient 1 carries a homoplasmic mtDNA mutation (m.11778G > A). Seventeen metaphase II (MII) oocytes underwent pre-implantation genetic testing (PGT), while five MII oocytes were used for spindle transfer (ST), and one in vitro matured (IVM) metaphase I oocyte underwent early pronuclear transfer (ePNT). Patients 2–3 experienced multiple failed intracytoplasmic sperm injection (ICSI) and ICSI-assisted oocyte activation (AOA) cycles. For these patients, the obtained MII oocytes underwent an additional ICSI-AOA cycle, while the IVM oocytes were subjected to ST. Results: For patient 1, PGT-M confirmed mutation loads close to 100%. All ST-reconstructed oocytes fertilized and cleaved, of which one progressed to the blastocyst stage. The reconstructed ePNT-zygote reached the morula stage. These samples showed an average mtDNA carry-over rate of 2.9% ± 0.8%, confirming the feasibility of NT to reduce mtDNA transmission. For patient 2–3 displaying fertilization failure, ST resulted in, respectively, 4/5 and 6/6 fertilized oocytes, providing evidence, for the first time, that NT can enable successful fertilization in this patient population. Conclusion: Our study showcases the repertoire of disorders for which NT can be beneficial, to overcome either mitochondrial disease transmission or failed fertilization after ICSI-AOA. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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313. Rebuilding INSPIRE together with the HEP community.
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Doglioni, C., Kim, D., Stewart, G.A., Silvestris, L., Jackson, P., Kamleh, W., and Christodoulaki, Stella
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DIGITAL libraries , *PARTICLE physics , *SCIENTIFIC community , *USER-centered system design , *INFORMATION display systems - Abstract
The INSPIRE digital library has been serving the scientific community for the almost past 50 years. Previously known as SPIRES, it was the first web site outside Europe and the first database on the web. Today, INSPIRE connects more than 100'000 scientists in High Energy Physics worldwide, with over 1 million scientific articles, thousands scientific profiles of authors, data, institution, experiments, conferences and jobs in High Energy Physics. In order to bring INSPIRE to the next level, we recently rebuilt the platform based on modern tools and infrastructure and released the new INSPIRE version in beta a few months ago. To ensure a successful beta release, we worked closely with the High Energy Physics community to identify the users' needs, drivers and barriers. In this paper, we describe the user-driven process that we followed, our testing strategy, as well as the user feedback following the INSPIRE beta release. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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314. Retrospective Study on Prevalence, Specificity, Sex, and Age Distribution of Alloimmunization in Two General Hospitals in Athens.
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Politou, Marianna, Valsami, Serena, Dryllis, Georgios, Christodoulaki, Maria, Cheropoulou, Christina, Pouliakis, Abraham, Baka, Maria, and Stamoulis, Konstantinos
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AGE distribution , *BLOOD transfusion , *IMMUNIZATION , *IMMUNOGLOBULINS , *SEX distribution , *DISEASE prevalence , *RETROSPECTIVE studies , *DATA analysis software , *DESCRIPTIVE statistics - Abstract
Objective: Blood transfusion is a common lifesaving treatment but it is often complicated with alloimmunization. Previously studies in Greece have concentrated on alloimmunization in multiply transfused thalassemic patients or antenatal women. However, the relative frequency of red blood cell (RBC) alloantibodies in the general patient population has not been studied so far. The aim of the present retrospective study was to estimate the prevalence and specificity of RBC alloantibodies in a large cohort of patients in two general hospitals and their association with age, sex, and the patients' clinic of hospitalization. Materials and Methods: Data from 2012 to 2016 from the "Sismanogleio" and "Thriasio" general hospitals in Athens, Greece, were studied retrospectively. Statistical analysis was performed with SAS for Windows 9.4. Results: Six hundred twenty-six patients (626/53800, 1.16%) were alloimmunized for one or more alloantibodies. The mean age was 67.99±17.56 years. Most antibodies were found in women [62.66% (438/699) in women vs. 37.34% (261/699) in men (p=0.0007)], while the vast majority of antibodies (66.81%) were found in patients aged 61-90. The most frequent antibody was anti-Kell (26.61%), followed by anti-E (16.02%), anti-D (15.02%), anti-Jka (5.87%), and anti-M (5.72%). Anti-C (81.48%, n=27) and anti-Cw (54.17%, n=24) tended to be found more often in patients with multiple antibodies. Most alloimmunized cases were found in general surgery (42.65%) and internal medicine departments (38.66%). Conclusion: According to our results, the alloimmunization data in a general patient population in Greece were consistent with the majority of studies in the international literature. Whether a strategy at national level needs to be directed towards extending matching for the whole population or towards applying sensitive and compulsory indirect antiglobulin tests before any transfusions in order to efficiently prevent alloimmunization remains an issue of debate. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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315. The effect of 0.5 L 6 % hydroxyethyl starch 130/0.42 versus 1 L Ringer's lactate preload on the hemodynamic status of parturients undergoing spinal anesthesia for elective cesarean delivery using arterial pulse contour analysis.
- Author
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Matsota, Paraskevi, Karakosta, Agathi, Pandazi, Ageliki, Niokou, Dimitra, Christodoulaki, Kalliopi, and Kostopanagiotou, Georgia
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SPINAL anesthesia , *CESAREAN section , *HEMODYNAMICS , *HYPOTENSION , *EPHEDRINE , *PHENYLEPHRINE - Abstract
Purpose: Fluid loading attenuates the hypotensive response to spinal anesthesia (SA). This study aimed to compare the preload efficacy of 0.5 L hydroxyethyl starch (HES) versus 1 L Ringer's lactate (R/L) in the prevention of hypotension after SA for elective cesarean delivery (CD). Assessment of maternal hemodynamic variables using FloTrac/Vigileo™ and neonatal outcome constituted secondary outcomes. Methods: Thirty-two ASA I/II parturients scheduled for elective CD were preloaded with either 1 L R/L (Group R/L, n = 16) or 0.5 L HES 6 % 130/0.42 (Group T, n = 16) approximately 25 min before SA. Hypotension, defined as a 20 % decrease of systolic arterial pressure (SAP) from baseline or SAP <100 mmHg, was treated with vasopressors according to a predetermined algorithm. The overall duration of hypotensive episodes and the total amount of vasopressors administered determined the severity of the hemodynamic instability. Results: The incidence of hypotension was 73.3 % in Group R/L and 46.7 % in Group T. HES compared to R/L preload was associated with a shorter overall duration of hypotensive episodes ( p < 0.001), a significantly less usage of ephedrine and phenylephrine ( p = 0.015 and p = 0.029, respectively) and a greater impact, although not statistically significant, on cardiac index (CI) and stroke volume index (SVI). Although no statistical difference was detected between groups over time, there was a significant drop in CI, SVI and SAP within groups ( p < 0.001) up to 14 min after SA. No difference was recorded in neonatal outcome. Conclusions: Preloading with 0.5 L HES 130/0.42 produced more stable hemodynamics compared to 1 L R/L solution in obstetric patients. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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316. Pronuclear transfer rescues poor embryo development of in vitro -grown secondary mouse follicles.
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Christodoulaki A, He H, Zhou M, De Roo C, Baetens M, De Pretre T, Fakhar-I-Adil M, Menten B, Van Soom A, Stoop D, Boel A, and Heindryckx B
- Abstract
Study Question: Is pronuclear transfer (PNT) capable of restoring embryo developmental arrest caused by cytoplasmic inferiority of in vitro -grown (IVG) mouse oocytes?, Summary Answer: PNT to in vivo matured cytoplasm significantly improved embryo development of IVG mouse oocytes, leading to living, fertile offspring., What Is Known Already: In vitro follicle culture has been considered as a fertility preservation option for cancer patients. Studies describing the culture of human follicles remain scarce, owing to low availability of tissue. Mouse models have extensively been used to study and optimize follicle culture. Although important achievements have been accomplished, including the production of healthy offspring in mice, IVG oocytes are of inferior quality when compared to in vivo -grown oocytes, likely because of cytoplasmic incompetence., Study Design Size Duration: The study was carried out from September 2020 to February 2022. In total, 120 15-day-old B6D2 mice were used to perform secondary follicle culture and assess the quality of IVG oocytes. In vivo -grown control oocytes were obtained from 85 8- to 12-week-old B6D2 mice, following ovarian stimulation. For sperm collection, four B6D2 males between 10 and 14 weeks old were used. For embryo transfer, 14 8- to 12-week-old CD1 females served as surrogate mothers and 10 CD1 vasectomized males 10-24 weeks old were used to generate pseudo-pregnant females. Finally, for mating, four B6D2 female mice aged 8-10 weeks and two B6D2 male mice aged 10 weeks old were used to confirm the fertility of nuclear transfer (NT)-derived pups., Participants/materials Setting Methods: Secondary follicles from 15-day-old B6D2 mice were isolated from the ovaries and cultured for 9 days, before a maturation stimulus was given. Following 16-18 h of maturation, oocytes were collected and evaluated on maturation rate, oocyte diameter, activation rate, spindle morphology, calcium-releasing ability, and mitochondrial membrane potential. For every experiment, in vivo -grown oocytes were used as a control for comparison. When cytoplasmic immaturity and poor embryo development were confirmed in IVG oocytes, PNT was performed. For this, the pronuclei from IVG oocytes, created following parthenogenetic activation and IVF, were transferred to the cytoplasm of fertilized, in vivo -grown oocytes. Genetic analysis and embryo transfer of the generated embryos were implemented to confirm the safety of the technique., Main Results and the Role of Chance: Following 9 days of follicle culture, 703 oocytes were collected, of which 76% showed maturation to the metaphase II stage. Oocyte diameters were significantly lower in IVG oocytes, measuring 67.4 μm versus 73.1 μm in controls ( P < 0.001). Spindle morphology did not differ significantly between IVG and control oocytes, but calcium-releasing ability was compromised in the IVG group. An average calcium release of 1.62 arbitrary units was observed in IVG oocytes, significantly lower than 5.74 in control oocytes ( P < 0.001). Finally, mitochondrial membrane potential was inferior in IVG compared to the control group, reaching an average value of 0.95 versus 2.27 ( P < 0.001). Developmental potential of IVG oocytes was assessed following parthenogenetic activation with strontium chloride (SrCl
2 ). Only 59.4% of IVG oocytes cleaved to two cells and 36.3% reached the blastocyst stage, significantly lower than 89.5% and 88.2% in control oocytes, respectively ( P < 0.001 and 0.001). Both PNT and spindle transfer (ST) were explored in pilot experiments with parthenogenetically activated oocytes, as a means to overcome poor embryo development. After the added value of NT was confirmed, we continued with the generation of biparental embryos by PNT. For this purpose, IVG and control oocytes first underwent IVF. Only 15.5% of IVG oocytes were normally fertilized, in contrast to 45.5% in controls ( P < 0.001), with resulting failure of blastocyst formation in the IVG group (0 versus 86.2%, P < 0.001). When the pronuclei of IVG zygotes were transferred to the cytoplasm of control zygotes, the blastocyst rate was restored to 86.9%, a similar level as the control. Genetic analysis of PNT embryos revealed a normal chromosomal profile, to a rate of 80%. Finally, the generation of living, fertile offspring from PNT was possible following embryo transfer to surrogate mothers., Large-Scale Data: N/A., Limitations Reasons for Caution: Genetic profiles of analysed embryos from PNT originate from groups that are too small to draw concrete conclusions, whilst ST, which would be the preferred NT approach, could not be used for the generation of biparental embryos owing to technical limitations. Even though promising, the use of PNT should be considered as experimental. Furthermore, results were acquired in a mouse model, so validation of the technique in human IVG oocytes needs to be performed to evaluate the clinical relevance of the technology. The genetic profiles from IVG oocytes, which would be the ultimate characterization for chromosomal abnormalities, were not analysed owing to limitations in the reliable analysis of single cells., Wider Implications of the Findings: PNT has the ability to overcome the poor cytoplasmic quality of IVG mouse oocytes. Considering the low maturation efficiency of human IVG oocytes and potential detrimental effects following long-term in vitro culture, NT could be applied to rescue embryo development and could lead to an increased availability of good quality embryos for transfer., Study Funding/competing Interests: A.C. is a holder of FWO (Fonds voor Wetenschappelijk Onderzoek) grants (1S80220N and 1S80222N). B.H. and A.V.S. have been awarded with a special BOF (Bijzonder Onderzoeksfonds), GOA (Geconcerteerde onderzoeksacties) 2018000504 (GOA030-18 BOF) funding. B.H. has been receiving unrestricted educational funding from Ferring Pharmaceuticals (Aalst, Belgium). The authors declare that they have no conflict of interest., Competing Interests: The authors declare that they have no conflict of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology.)- Published
- 2024
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317. Characterization of ovarian tissue oocytes from transgender men reveals poor calcium release and embryo development, which might be overcome by spindle transfer.
- Author
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Christodoulaki A, He H, Zhou M, Cardona Barberán A, De Roo C, Chuva De Sousa Lopes SM, Baetens M, Menten B, Van Soom A, De Sutter P, Weyers S, Boel A, Stoop D, and Heindryckx B
- Subjects
- Pregnancy, Male, Humans, Female, Calcium, DNA Copy Number Variations, Oocytes, Embryonic Development, Testosterone pharmacology, In Vitro Oocyte Maturation Techniques methods, Transgender Persons
- Abstract
Study Question: Can spindle transfer (ST) overcome inferior embryonic development of in vitro matured ovarian tissue oocytes (OTO-IVM) originating from testosterone-treated transgender men?, Summary Answer: ST shows some potential to overcome the embryo developmental arrest observed in OTO-IVM oocytes from transgender men., What Is Known Already: OTO-IVM is being applied as a complementary approach to increase the number of oocytes/embryos available for fertility preservation during ovarian tissue cryopreservation in cancer patients. OTO-IVM has also been proposed for transgender men, although the potential of their oocytes remains poorly investigated. Currently, only one study has examined the ability of OTO-IVM oocytes originating from transgender men to support embryo development, and that study has shown that they exhibit poor potential., Study Design, Size, Duration: Both ovaries from 18 transgender men undergoing oophorectomy were collected for the purposes of this study, from November 2020 to September 2022. The patients did not wish to cryopreserve their tissue for fertility preservation and donated their ovaries for research. All patients were having testosterone treatment at the time of oophorectomy and some of them were also having menses inhibition treatment., Participants/materials, Setting, Methods: Sibling ovaries were collected in either cold or warm medium, to identify the most optimal collection temperature. Cumulus oocyte complexes (COCs) from each condition were isolated from the ovarian tissue and matured in vitro for 48 h. The quality of OTO-IVM oocytes was assessed by calcium pattern releasing ability, embryo developmental competence following ICSI, and staining for mitochondrial membrane potential. In vitro matured metaphase I (MI) oocytes, germinal vesicle (GV) oocytes, and in vivo matured oocytes with aggregates of smooth endoplasmic reticulum (SERa) were donated from ovarian stimulated women undergoing infertility treatment and these served as Control oocytes for the study groups. ST was applied to overcome poor oocyte quality. Specifically, enucleated mature Control oocytes served as cytoplasmic recipients of the OTO-IVM spindles from the transgender men. Embryos derived from the different groups were scored and analysed by shallow whole genome sequencing for copy number variations (CNVs)., Main Results and the Role of Chance: In total, 331 COCs were collected in the cold condition (OTO-Cold) and 282 were collected in the warm condition (OTO-Warm) from transgender men. The maturation rate was close to 54% for OTO-Cold and 57% for OTO-Warm oocytes. Control oocytes showed a calcium releasing ability of 2.30 AU (n = 39), significantly higher than OTO-Cold (1.47 AU, P = 0.046) oocytes (n = 33) and OTO-Warm (1.03 AU, P = 0.036) oocytes (n = 31); both values of calcium release were similar between the two collection temperatures. Mitochondrial membrane potential did not reveal major differences between Control, OTO-Warm, and OTO-Cold oocytes (P = 0.417). Following ICSI, 59/70 (84.2%) of Control oocytes were fertilized, which was significantly higher compared to 19/47 (40.4%) of OTO-Cold (P < 0.01) and 24/48 (50%) of OTO-Warm oocytes (P < 0.01). In total, 15/59 (25.4%) blastocysts were formed on Day 5 in the Control group, significantly higher than 0/19 (0%) from the OTO-Cold (P = 0.014) and 1/24 (4.1%) in OTO-Warm oocytes (P = 0.026). Application of ST rescued the poor embryo development, by increasing the Day 5 blastocyst rate from 0% (0/19) to 20.6% (6/29) (P = 0.034), similar to that in the ICSI-Control group (25.4%, 15/59). A normal genetic profile was observed in 72.7% (8/11) of OTO-Cold, 72.7% (8/11) of OTO-Warm and 64.7% (11/17) of Control Day 3-Day 5 embryos. After ST was applied for OTO-IVM oocytes, 41.1% (7/17) of the embryos displayed normal genetic patterns, compared to 57.1% (4/7) among ST-Control Day 3-Day 5 embryos., Large Scale Data: N/A., Limitations, Reasons for Caution: Due to the limited access to human oocytes and ovarian tissue, our results should be interpreted with some caution, as only a limited number of human oocytes and embryos could be investigated., Wider Implications of the Findings: The results of this study, clearly indicate that OTO-IVM oocytes originating from transgender patients are of inferior quality, which questions their use for fertility preservation. The poor quality is likely to be related to cytoplasmic factors, supported by the increased blastocyst numbers following application of ST. Future research on OTO-IVM from transgender men should focus on the cytoplasmic content of oocytes or supplementation of media with factors that promote cytoplasmic maturation. A more detailed study on the effect of the length of testosterone treatment is also currently missing for more concrete guidelines and guidance on the fertility options of transgender men. Furthermore, our study suggests a potentially beneficial role of experimental ST in overcoming poor embryo development related to cytoplasmic quality., Study Funding/competing Interest(s): A.C. is a holder of FWO grants (1S80220N and 1S80222N). A.B. is a holder of an FWO grant (1298722N). B.H. and A.V.S. have been awarded with a special BOF (Bijzonder Onderzoeksfonds), GOA (Geconcerteerde onderzoeksacties) and 2018000504 (GOA030-18 BOF) funding. B.H. has additional grants from FWO-Vlaanderen (Flemish Fund for Scientific Research, G051516N and G1507816N) and Ghent University Special Research Fund (Bijzonder Onderzoeksfonds, BOF funding (BOF/STA/202109/005)), and has been receiving unrestricted educational funding from Ferring Pharmaceuticals (Aalst, Belgium). The authors declare that they have no conflict of interest., Trial Registration Number: N/A., (© The Author(s) 2023. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)
- Published
- 2023
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318. Expression of Retroelements in Mammalian Gametes and Embryos.
- Author
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Mastora E, Christodoulaki A, Papageorgiou K, Zikopoulos A, and Georgiou I
- Subjects
- Alu Elements, Animals, Female, Humans, Male, Mice, Oocytes, Short Interspersed Nucleotide Elements, Long Interspersed Nucleotide Elements genetics, Retroelements genetics
- Abstract
Retroelements are genetic mobile elements, expressed during male and female gamete differentiation. Retrotransposons are normally regulated by the methylation machinery, chromatin modifications, non-coding RNAs, and transcription factors, while retrotransposition control is of vital importance in cellular proliferation and differentiation process. Retrotransposition requires a transcription step, by a cellular RNA polymerase, followed by reverse transcription of an RNA intermediate to cDNA and its integration into a new genomic locus. Long interspersed elements (LINEs), human endogenous retroviruses (HERVs), short interspersed elements (SINEs) and SINE-VNTR-Alu elements (SVAs) constitute about half of the human genome, play a crucial role in genome organization, structure and function and interfere with several biological procedures. In this mini review, we discuss recent data regarding retroelement expression (LINE-1, HERVK-10, SVA and VL30) and retrotransposition events in mammalian oocytes and spermatozoa, as well as the importance of their impact on human and mouse preimplantation embryo development., (Copyright © 2021 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)
- Published
- 2021
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319. Prospects of Germline Nuclear Transfer in Women With Diminished Ovarian Reserve.
- Author
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Christodoulaki A, Boel A, Tang M, De Roo C, Stoop D, and Heindryckx B
- Subjects
- Animals, Female, Fertilization, Fertilization in Vitro, Humans, Infertility, Female therapy, Maternal Age, Mitochondrial Diseases metabolism, Oocyte Donation, Oocyte Retrieval, Oocytes metabolism, Ovarian Diseases, Pregnancy, Reproductive Techniques, Assisted, Spindle Apparatus, Zygote metabolism, Nuclear Transfer Techniques, Oocytes cytology, Ovarian Reserve
- Abstract
Diminished ovarian reserve (DOR) is associated with a reduced quantity and quality of the retrieved oocytes, usually leading to poor reproductive outcomes which remain a great challenge for assisted reproduction technology (ART). Women with DOR often have to seek for oocyte donation, precluding genetically related offspring. Germline nuclear transfer (NT) is a novel technology in ART that involves the transfer of the nuclear genome from an affected oocyte/zygote of the patient to the cytoplast of an enucleated donor oocyte/zygote. Therefore, it offers opportunities for the generation of genetically related embryos. Currently, although NT is clinically applied only in women with serious mitochondrial DNA disorders, this technology has also been proposed to overcome certain forms of female infertility, such as advanced maternal age and embryo developmental arrest. In this review, we are proposing the NT technology as a future treatment option for DOR patients. Strikingly, the application of different NT strategies will result in an increase of the total number of available reconstituted embryos for DOR patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Christodoulaki, Boel, Tang, De Roo, Stoop and Heindryckx.)
- Published
- 2021
- Full Text
- View/download PDF
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