76 results on '"Chronopoulou E"'
Search Results
2. Effect of under‐ and overfeeding on sheep and goat milk and plasma enzymes activities related to oxidation
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Tsiplakou, E., Mitsiopoulou, C., Mavrommatis, A., Karaiskou, C., Chronopoulou, E. G., Mavridis, G., Sotirakoglou, K., Labrou, N. E., and Zervas, G.
- Published
- 2018
- Full Text
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3. P-357 Predicting live birth following single euploid frozen blastocyst transfer - does the journey matter?
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Theodorou, E, primary, Cardenas Armas, D, additional, Chronopoulou, E, additional, Jones, B.P, additional, Ozturk, O, additional, Serhal, P, additional, and Ben Nagi, J, additional
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- 2022
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4. P-399 Effect of male body mass index on miscarriage rate following fertility treatment, a systematic review and meta-analysis
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Halimeh, R, primary, Chronopoulou, E, additional, Duran, M, additional, Saab, W, additional, Serhal, P, additional, and Seshadri, S, additional
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- 2022
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5. P-122 Optimising IUI; a systematic review and network meta-analysis
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Chronopoulou, E, primary, Shaikh, S, additional, Gaetano-Gil, A, additional, Raperport, C, additional, Tsiveriotis, K, additional, Al Wattar, B.H, additional, Zamora, J, additional, and Bhide, P, additional
- Published
- 2022
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6. P–625 Does endogenous progesterone play a role in unexplained infertility? A systematic review
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Raperport, C, primary, Chronopoulou, E, additional, Homburg, R, additional, Khan, K, additional, and Bhide, P, additional
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- 2021
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7. Social and occupational health protection for self-employed farmers in the European Union
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Kotsioni, I., Chatzis, C., Chronopoulou, E., and Linos, A.
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- 2007
- Full Text
- View/download PDF
8. Capecitabine, Oxaliplatin, Irinotecan, and Bevacizumab Combination Followed by Pazopanib plus Capecitabine Maintenance for High-Grade Gastrointestinal Neuroendocrine Carcinomas
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Alifieris, C.E. Griniatsos, J. Delis, S.G. Nikolaou, M. Avgoustou, C. Panagiotidis, M.I. Souferi-Chronopoulou, E. Trafalis, D.T.
- Abstract
Objectives:Gastrointestinal neuroendocrine carcinoma (NEC) is a lethal, uncommon, and understudied neoplasm. We present the efficacy and safety of first-line capecitabine (CP), oxaliplatin, irinotecan, and bevacizumab (CAPOXIRI-BEV) combination followed by pazopanib plus CP maintenance therapy in patients with advanced high-grade poorly differentiated gastrointestinal NEC.Methods:This was a two-stage phase II study conducted at multiple institutions. Patients were consecutively enrolled and had advanced NEC of the colon or small bowel. Patients received irinotecan 125 mg/m2, oxaliplatin 80 mg/m2on day 1, CP 1000 mg/m2twice daily on days 1 to 14, plus bevacizumab 8 mg/kg on day 1 for six 21-day cycles. Maintenance therapy was given to those who responded (complete response/partial response) or had stable disease after 6 cycles with CAPOXIRI-BEV with pazopanib 800 mg daily plus CP 1600 mg/m2daily on days 1 to 14 every 3 weeks until disease progression or unacceptable toxicity. Patients who progressed on CAPOXIRI-BEV received standard etoposide-carboplatin. The primary endpoint was overall response rate.Results:Twenty-two patients were enrolled of whom 19 were evaluable. The median age was 60 years. The overall response rate (3 complete response/6 partial response) was 47.4% (95% confidence interval: 29.5-76.1), the overall disease control rate was 78.9% (95% confidence interval: 62.6-99.6), and, at median 30 (11 to 41 mo) months' follow-up, 5 patients (26.3%) were still alive. Median progression-free survival was 13 months, and the 1-year progression-free survival rate was 52.6%. The median overall survival was 29 months. The median overall survival of the 9 patients who responded versus those with stable disease/progressive disease was 30.5 versus 14 months, respectively. The median duration of response was 16 months. Predictable toxicity was observed.Conclusions:First-line CAPOXIRI-BEV followed by pazopanib plus CP maintenance therapy for advanced NEC demonstrates promising efficacy and predictable toxicity. Further investigation is warranted. © 2020 Lippincott Williams and Wilkins. All rights reserved.
- Published
- 2020
9. Plant adaptation to stress conditions: The case of glutathione S-transferases (GSTs)
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Stavridou, E., Voulgari, G., Bosmali, I., Chronopoulou, E. G., Cicero, L. L., Lo Piero, A. R., Labrou, N. E., Tsaftaris, A., Nianiou-Obeidat, I., and Madesis, P.
- Subjects
Salinity ,Oxidative stress ,Glutathione transferase ,Herbicide detoxification ,GST ,Heavy metal stress ,High and low temperatures ,Tolerance mechanisms ,Water deficit - Published
- 2018
10. Small cell ovarian carcinoma hypercalcemic type and endometrial adenocarcinoma in a 49-year-old patient: a very rare case
- Author
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Kalogeropoulos, S., primary, Chronopoulou, E., primary, Kourea, E., primary, Siampalis, A., primary, Kaponis, A., primary, and Decavalas, G. O, primary
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- 2019
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11. MT-ND5 Mutation Exhibits Highly Variable Neurological Manifestations at Low Mutant Load
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Ng, Y.S., Lax, N.Z., Maddison, P., Alston, C.L., Blakely, E.L., Hepplewhite, P.D., Riordan, G., Meldau, S., Chinnery, P.F., Pierre, G., Chronopoulou, E., Du, A., Hughes, I., Morris, A.A., Kamakari, S., Chrousos, G., Rodenburg, R.J.T., Saris, C.G.J., Feeney, C., Hardy, S.A., Sakakibara, T., Sudo, A., Okazaki, Y., Murayama, K., Mundy, H., Hanna, M.G., Ohtake, A., Schaefer, A.M., Champion, M.P., Turnbull, D.M., Taylor, R.W., Pitceathly, R.D.S., McFarland, R., Gorman, G.S., Ng, Y.S., Lax, N.Z., Maddison, P., Alston, C.L., Blakely, E.L., Hepplewhite, P.D., Riordan, G., Meldau, S., Chinnery, P.F., Pierre, G., Chronopoulou, E., Du, A., Hughes, I., Morris, A.A., Kamakari, S., Chrousos, G., Rodenburg, R.J.T., Saris, C.G.J., Feeney, C., Hardy, S.A., Sakakibara, T., Sudo, A., Okazaki, Y., Murayama, K., Mundy, H., Hanna, M.G., Ohtake, A., Schaefer, A.M., Champion, M.P., Turnbull, D.M., Taylor, R.W., Pitceathly, R.D.S., McFarland, R., and Gorman, G.S.
- Abstract
Contains fulltext : 191175.pdf (publisher's version ) (Open Access), Mutations in the m.13094T>C MT-ND5 gene have been previously described in three cases of Leigh Syndrome (LS). In this retrospective, international cohort study we identified 20 clinically affected individuals (13 families) and four asymptomatic carriers. Ten patients were deceased at the time of analysis (median age of death was 10years (range: 5.4months-37years, IQR=17.9years). Nine patients manifested with LS, one with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS), and one with Leber hereditary optic neuropathy. The remaining nine patients presented with either overlapping syndromes or isolated neurological symptoms. Mitochondrial respiratory chain activity analysis was normal in five out of ten muscle biopsies. We confirmed maternal inheritance in six families, and demonstrated marked variability in tissue segregation, and phenotypic expression at relatively low blood mutant loads. Neuropathological studies of two patients manifesting with LS/MELAS showed prominent capillary proliferation, microvacuolation and severe neuronal cell loss in the brainstem and cerebellum, with conspicuous absence of basal ganglia involvement. These findings suggest that whole mtDNA genome sequencing should be considered in patients with suspected mitochondrial disease presenting with complex neurological manifestations, which would identify over 300 known pathogenic variants including the m.13094T>C.
- Published
- 2018
12. The glutathione transferase family of Chlamydomonas reinhardtii: Identification and characterization of novel sigma class-like enzymes
- Author
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Chatzikonstantinou, M. Vlachakis, D. Chronopoulou, E. Papageorgiou, L. Papageorgiou, A.C. Labrou, N.E.
- Abstract
Understanding the genetic and molecular basis of the detoxifying mechanism in Chlamydomonas reinhardtii is an important goal towards the development of bioremediation tools for contaminated environments. Glutathione transferases (GSTs, EC 2.5.1.18) are phase II metabolic enzymes that play important role in the detoxification of xenobiotic compounds. GSTs have been characterized extensively in land plants and animals but no evidence has yet been reported for their presence in C. reinhardtii. A genome survey of C. reinhardtii revealed the presence of fifteen GST-like isoenzymes (CrGSTs). Comparison by multiple sequence alignment generated a dendrogram, revealing the phylogenetic relationships of CrGSTs with other well-characterized GST classes. Notably, we identified sequences that are most closely related to the sigma class enzymes which so far have only been found in animals. Two sigma class related isoenzymes (CrGST10 and CrGST7) were cloned, expressed in E. coli and their substrate specificity and kinetic properties were determined towards a range of different xenobiotic substrates. The structural and kinetic features of the enzymes were studied by molecular modelling and site-directed mutagenesis. The catalytic role of active-site residue Tyr7 and the roles of Trp99 in determining substrate specificity and thermostability were investigated. Analysis of GSTome in green algae provides an opportunity to shine light on the roles of GSTs in cellular detoxification mechanism as well as to develop new biotechnological and environmental applications. © 2016 Elsevier B.V.
- Published
- 2017
13. Effect of under- and overfeeding on sheep and goat milk and plasma enzymes activities related to oxidation
- Author
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Tsiplakou, E., primary, Mitsiopoulou, C., additional, Mavrommatis, A., additional, Karaiskou, C., additional, Chronopoulou, E. G., additional, Mavridis, G., additional, Sotirakoglou, K., additional, Labrou, N. E., additional, and Zervas, G., additional
- Published
- 2017
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14. G83(P) Emergency department management of children with decompensating inherited metabolic disease
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Gillam, MW, primary, Chronopoulou, E, additional, and Lyttle, MD, additional
- Published
- 2015
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15. Social and occupational health protection for self-employed farmers in the European Union
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Kotsioni, I. Chatzis, C. Chronopoulou, E. Linos, A.
- Abstract
Aim: The focus of this article deals with the diversity of national social security provisions specific to self-employed farmers in the European Union (EU) and attempts an initial research and categorisation of social protection provisions applying to the European population of self-employed farmers. Methods: An extensive internet search was performed to identify national social security provisions for self-employed farmers. A crude categorisation of social security provisions for self-employed farmers is attempted aiming to identify EU Member States (MS) that apply: (1) a general social protection scheme for all the population, (2) a social protection scheme specific for the totality of the self-employed population, and (3) a social protection system specific for self-employed farmers. National provisions for the coverage of self-employed farmers for occupational injuries and diseases are also categorised. Moreover a care study from Finland is presented describing the innovatory Finnish system of substitute farmers' services that allows self-employed farmers to be substituted in their farms in case of sickness, injury or holidays. Conclusion: Persons occupied in agriculture in the EU MS, while facing many of the same occupational risks, are covered to varying degrees by national social security schemes. An initial conclusion that was derived is that countries that apply special social security systems for self-employed farmers are more likely to include in the provisions of their systems the coverage for occupational injuries and diseases as well. The increased diversity of national provions regarding the protection of self-employed farmers should be further researched at the European level and efforts for the coordination of relevant national policies towards a more comprehensive coverage of farmers should be discussed. © 2007 Springer-Verlag.
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- 2007
16. Crystal structure of a tau class glutathione transferase 10 from Glycine max
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Skopelitou, K., primary, Muleta, A.W., additional, Papageorgiou, A.C., additional, Pavli, O., additional, Flemetakis, E., additional, Chronopoulou, E., additional, Skaracis, G.N., additional, and Labrou, N.E., additional
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- 2014
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17. Biocatalysis, Enzyme Engineering and Biotechnology
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Kotzia, G. A., primary, Platis, D., additional, Axarli, I. A., additional, Chronopoulou, E. G., additional, Karamitros, C., additional, and Labrou, N. E., additional
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- 2012
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18. Autoreactive IgG elicited in mice by the non-dominant but pathogenic thyroglobulin peptide (2495–2511): implications for thyroid autoimmunty
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CHRONOPOULOU, E, primary, MICHALAK, T I, additional, and CARAYANNIOTIS, G, additional
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- 1994
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19. Identification of a thyroiditogenic sequence within the thyroglobulin molecule.
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Chronopoulou, E, primary and Carayanniotis, G, additional
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- 1992
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20. Three-country snapshot of ornithine transcarbamylase deficiency
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Berna Seker Yilmaz, Julien Baruteau, Nur Arslan, Halil Ibrahim Aydin, Magalie Barth, Ayse Ergul Bozaci, Anais Brassier, Ebru Canda, Aline Cano, Efstathia Chronopoulou, Grainne M. Connolly, Lena Damaj, Charlotte Dawson, Dries Dobbelaere, Claire Douillard, Fatma Tuba Eminoglu, Sahin Erdol, Melike Ersoy, Sherry Fang, François Feillet, Gulden Gokcay, Emine Goksoy, Magali Gorce, Asli Inci, Banu Kadioglu, Fatih Kardas, Cigdem Seher Kasapkara, Gonca Kilic Yildirim, Deniz Kor, Melis Kose, Cecilia Marelli, Helen Mundy, Siobhan O’Sullivan, Burcu Ozturk Hismi, Radha Ramachandran, Agathe Roubertie, Mehtap Sanlilar, Manuel Schiff, Srividya Sreekantam, Karolina M. Stepien, Ozlem Uzun Unal, Yilmaz Yildiz, Tanyel Zubarioglu, Paul Gissen, and Seker Yilmaz B., Baruteau J., ARSLAN N., AYDIN H. İ. , Barth M., Bozaci A. E. , Brassier A., CANDA E., Cano A., Chronopoulou E., et al.
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INVOLVEMENT ,MICROBIOLOGY ,LIVER ,Mikrobiyoloji ,Temel Tıp Bilimleri ,BIOLOGY ,Life Sciences (LIFE) ,hyperammonaemia ,Sağlık Bilimleri ,FREQUENCY ,DIAGNOSIS ,Fundamental Medical Sciences ,Biochemistry ,BIOLOGY & BIOCHEMISTRY ,General Biochemistry, Genetics and Molecular Biology ,Tıbbi Biyoloji ,Biyokimya ,ornithine transcarbamylase deficiency ,neonatal-onset ,late-onset ,asymptomatic ,protein restriction ,ammonia scavengers ,liver transplantation ,Yaşam Bilimleri ,Health Sciences ,Biyoloji ve Biyokimya ,Ecology, Evolution, Behavior and Systematics ,Medical Biology ,Temel Bilimler ,Biochemistry (medical) ,GENE-THERAPY ,Paleontology ,Life Sciences ,Biyokimya (tıbbi) ,UREA CYCLE DISORDERS ,EFFICACY ,Tıp ,Space and Planetary Science ,Yaşam Bilimleri (LIFE) ,DISEASES ,SAFETY ,BİYOLOJİ ,Medicine ,Natural Sciences - Abstract
X-linked ornithine transcarbamylase deficiency (OTCD) is the most common urea cycle defect. The disease severity ranges from asymptomatic carrier state to severe neonatal presentation with hyperammonaemic encephalopathy. We audited the diagnosis and management of OTCD, using an online 12-question-survey that was sent to 75 metabolic centres in Turkey, France and the UK. Thirty-nine centres responded and 495 patients were reported in total. A total of 208 French patients were reported, including 71 (34%) males, 86 (41%) symptomatic and 51 (25%) asymptomatic females. Eighty-five Turkish patients included 32 (38%) males, 39 (46%) symptomatic and 14 (16%) asymptomatic females. Out of the 202 UK patients, 66 (33%) were male, 83 (41%) asymptomatic and 53 (26%) symptomatic females. A total of 19%, 12% and 7% of the patients presented with a neonatal-onset phenotype in France, Turkey and the UK, respectively. Vomiting, altered mental status and encephalopathy were the most common initial symptoms in all three countries. While 69% in France and 79% in Turkey were receiving protein restriction, 42% were on a protein-restricted diet in the UK. A total of 76%, 47% and 33% of patients were treated with ammonia scavengers in Turkey, France and the UK, respectively. The findings of our audit emphasize the differences and similarities in manifestations and management practices in three countries., Medical Research Council [MR/S019111/1]; National Institute of Health Research Senior Investigator Award [NIHR202370]; Medical Research Council Clinician Scientist Fellowship [MR/T008024/1]; NIHR Great Ormond Street Hospital Biomedical Research Centre, This work was supported by the Medical Research Council grant, reference: MR/S019111/1. PG is supported by a National Institute of Health Research Senior Investigator Award (Reference NIHR202370). J.B. is supported by Medical Research Council Clinician Scientist Fellowship MR/T008024/1 and NIHR Great Ormond Street Hospital Biomedical Research Centre. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health.
- Published
- 2022
21. Complexities of Management of Atypical Ventricular Fibrillation Storm in a Young Patient With TANGO2.
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Gonzalez Corcia MC, Bradshaw C, Chronopoulou E, Shortland J, O'Sullivan B, and Murphy T
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TANGO2 deficiency disorder, a rare autosomal recessive genetic disorder characterised by biallelic loss-of-function variants in the TANGO2 gene, was first described in 2016. This disorder involves the transport and Golgi organisation homologue, impacting Golgi membrane redistribution into the endoplasmic reticulum. Clinically, affected individuals exhibit a multiorgan phenotype, with prominent neurological manifestations such as developmental delay and regression. Metabolic crises, triggered by minor infections or fasting, are a hallmark of the disorder. We present the case of a 5-year-old boy diagnosed with TANGO2 deficiency disorder who experienced a refractory-to-treatment ventricular arrhythmia storm. The patient's clinical course was marked by rhabdomyolysis-induced muscle pain, weakness and dark urine. Despite aggressive medical management during intercurrent illness, including hyperhydration, maintenance of normoglycemia and correction of electrolyte abnormalities, the patient's condition deteriorated, leading to a life-threatening ventricular arrhythmia storm. In a life-saving therapeutic approach, the patient underwent a thoracoscopic left sympathectomy during extracorporeal membrane oxygenation (ECMO) support. Remarkably, this intervention resulted in the termination of the ventricular arrhythmia storm. The case underscores the challenges in managing TANGO2 deficiency disorder-associated complications and highlights the potential role of innovative interventions, such as sympathectomy during ECMO, in critical and refractory cases. This case contributes to the understanding of the clinical spectrum of TANGO2 deficiency disorder and emphasises the need for further research into targeted therapies for this rare metabolic condition, where current treatment strategies focus on symptom management., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 M. Cecilia Gonzalez Corcia et al.)
- Published
- 2024
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22. The impact of adrenocortical carcinoma hormone secreting status as a predictor of poor survival: a systematic review and meta-analysis.
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Nastos C, Papaconstantinou D, Paspala A, Pararas N, Vryonidou A, Pikouli A, Chronopoulou E, Lechou A, Peppa M, and Pikoulis E
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- Humans, Prognosis, Survival Rate, Hydrocortisone metabolism, Hydrocortisone blood, Adrenocortical Carcinoma mortality, Adrenocortical Carcinoma metabolism, Adrenocortical Carcinoma pathology, Adrenal Cortex Neoplasms mortality, Adrenal Cortex Neoplasms metabolism, Adrenal Cortex Neoplasms pathology
- Abstract
Purpose: Adrenocortical carcinoma (ACC) poses a significant challenge in healthcare due to its aggressive nature and rarity. Prior reports suggest a poorer prognosis associated with hormone-secreting neoplasms. This study aims to assess the impact of ACC hormonal status on patients' oncologic survival., Methods: A comprehensive literature search of the Medline, Embase, Web of Science, CINAHL, CENTRAL and clinicaltrials.gov databases was undertaken. Utilized data involved Hazard Ratios derived from multivariable analysis in order to minimize exposure to confounding bias. Included studies were subsequently meta-analyzed using a Random effects model., Results: Twelve studies incorporating 4483 patients were included in the quantitative analysis. Hormonally active ACCs comprised 48% of the entire pooled patient cohort and were found to be associated with significantly worse Overall Survival (HR 1.57, 95% Confidence Interval 1.39-1.78, p < 0.001). Disease-Free Survival was comparably impacted (HR 1.32, 95% CI 1.11-1.57, p < 0.001). Furthermore, cortisol secreting ACCs specifically, were also found to be associated with a 48% increase in the hazard of death or disease recurrence. Interstudy statistical heterogeneity was minimal among evaluated outcomes., Conclusions: Hormone-producing ACCs exhibit a poorer prognosis compared to non-secreting counterparts, with a 57% increased risk of death and a 32% increased risk of recurrence. These findings support the hypothesis that hormone production signifies an adverse tumor-specific feature, particularly when leading to hypercortisolemia, indicating an aggressive disease phenotype., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
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- 2024
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23. Optimizing intrauterine insemination: A systematic review and meta-analysis of the effectiveness and safety of clinical treatment add-ons.
- Author
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Chronopoulou E, Gaetano-Gil A, Shaikh S, Raperport C, Al Wattar BH, Ruiz-Calvo G, Zamora J, and Bhide P
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- Humans, Female, Pregnancy, Randomized Controlled Trials as Topic, Insemination, Artificial methods, Pregnancy Rate
- Abstract
Introduction: Intrauterine insemination (IUI) is one of the most widespread fertility treatments. However, IUI protocols vary significantly amongst fertility clinics. Various add-on interventions have been proposed to boost success rates. These are mostly chosen arbitrarily or empirically. The aim of this systematic review and meta-analysis is to assess the effectiveness and safety of add-on interventions to the standard IUI protocol and to provide evidence-based recommendations on techniques used to optimize the clinical outcomes of IUI treatment., Material and Methods: Systematic review and meta-analyses were performed in accordance with PRISMA guidelines. A computerized literature search was performed from database inception to May 2023. Randomized controlled trials (RCTs) were included reporting on couples/single women undergoing IUI with any protocol for any indication using partner's or donor sperm. A meta-analysis based on random effects was performed for each outcome and add-on. Three authors independently assessed the trials for quality and risk of bias and overall certainty of evidence. Uncertainties were resolved through consensus. Primary outcomes were ongoing pregnancy rate (OPR) or live birth rate (LBR) per cycle/per woman randomized. Registration number PROSPERO: CRD42022300857., Results: Sixty-six RCTs were included in the analysis (16 305 participants across 20 countries). Vaginal progesterone as luteal phase support in stimulated cycles was found to significantly increase LBR/OPR (RR 1.37, 95% CI 1.09-1.72, I
2 = 4.9%) (moderate/low certainty of the evidence). Endometrial scratch prior/during stimulated IUI cycles may increase LBR/OPR (RR 1.44, 95% CI 1.03-2.01, I2 = 1.8%), but evidence is very uncertain. Results from two studies suggest that follicular phase ovarian stimulation increases LBR/OPR (RR 1.39, 95% CI 1.00-1.94, I2 = 0%) (low certainty of evidence). No significant difference was seen for the primary outcome for the other studied interventions., Conclusions: The findings of this systematic review and meta-analysis suggest that vaginal luteal phase progesterone support probably improves LBR/OPR in stimulated IUI treatments. In view of moderate/low certainty of the evidence more research is needed for solid conclusions. Further research is also recommended for the use of endometrial scratch and ovarian stimulation. Future studies should report on results according to subfertility background as it is possible that different add-ons could benefit specific patient groups., (© 2024 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).)- Published
- 2024
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24. Biallelic PTPMT1 variants disrupt cardiolipin metabolism and lead to a neurodevelopmental syndrome.
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Falabella M, Pizzamiglio C, Tabara LC, Munro B, Abdel-Hamid MS, Sonmezler E, Macken WL, Lu S, Tilokani L, Flannery PJ, Patel N, Pope SAS, Heales SJR, Hammadi DBH, Alston CL, Taylor RW, Lochmuller H, Woodward CE, Labrum R, Vandrovcova J, Houlden H, Chronopoulou E, Pierre G, Maroofian R, Hanna MG, Taanman JW, Hiz S, Oktay Y, Zaki MS, Horvath R, Prudent J, and Pitceathly RDS
- Abstract
Primary mitochondrial diseases (PMDs) are among the most common inherited neurological disorders. They are caused by pathogenic variants in mitochondrial or nuclear DNA that disrupt mitochondrial structure and/or function, leading to impaired oxidative phosphorylation (OXPHOS). One emerging subcategory of PMDs involves defective phospholipid (PL) metabolism. Cardiolipin (CL), the signature PL of mitochondria, resides primarily in the inner mitochondrial membrane, where it is biosynthesised and remodelled via multiple enzymes and is fundamental to several aspects of mitochondrial biology. Genes that contribute to CL biosynthesis have recently been linked with PMD. However, the pathophysiological mechanisms that underpin human CL-related PMDs are not fully characterised. Here, we report six individuals, from three independent families, harbouring biallelic variants in PTPMT1, a mitochondrial tyrosine phosphatase required for de novo CL biosynthesis. All patients presented with a complex, neonatal/infantile onset neurological and neurodevelopmental syndrome comprising developmental delay, microcephaly, facial dysmorphism, epilepsy, spasticity, cerebellar ataxia and nystagmus, sensorineural hearing loss, optic atrophy, and bulbar dysfunction. Brain MRI revealed a variable combination of corpus callosum thinning, cerebellar atrophy, and white matter changes. Using patient-derived fibroblasts and skeletal muscle tissue, combined with cellular rescue experiments, we characterise the molecular defects associated with mutant PTPMT1 and confirm the downstream pathogenic effects that loss of PTPMT1 has on mitochondrial structure and function. To further characterise the functional role of PTPMT1 in CL homeostasis, we established a zebrafish ptpmt1 knockout model associated with abnormalities in body size, developmental alterations, decreased total CL levels, and OXPHOS deficiency. Together, these data indicate that loss of PTPMT1 function is associated with a new autosomal recessive PMD caused by impaired CL metabolism, highlight the contribution of aberrant CL metabolism towards human disease, and emphasise the importance of normal CL homeostasis during neurodevelopment., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain.)
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- 2024
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25. Impact of double trophectoderm biopsy on reproductive outcomes following single euploid blastocyst transfer.
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Theodorou E, Chronopoulou E, Ozturk O, Brunetti X, Serhal P, and Ben-Nagi J
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- Humans, Female, Retrospective Studies, Pregnancy, Adult, Biopsy, Blastocyst pathology, Pregnancy Rate, Live Birth, Vitrification, Pregnancy Outcome, Preimplantation Diagnosis, Embryo Transfer methods
- Abstract
Objectives: To study the effect of double trophectoderm biopsy on clinical outcomes following single euploid blastocyst transfer., Study Design: Retrospective cohort study of 2046 single euploid frozen-thawed blastocyst transfers from January 2015 to June 2022 in a single centre. All patients undergoing a frozen-thawed embryo transfer (FTET) cycle with euploid blastocysts, biopsied for any indication, were included. The outcomes were compared for blastocysts which were biopsied and vitrified once (Group 1, n = 1684), biopsied once but vitrified twice (Group 2, n = 312) and biopsied and vitrified twice (Group 3n = 50). We adjusted for confounders and performed subgroup analysis for PGT-A, PGT-M and PGT-SR cycles. The primary outcome was live birth rate. Secondary outcomes included pregnancy, clinical pregnancy, birthweight and sex ratio., Results: After adjusting for confounders (previous failed euploid implantations, embryo quality and day of biopsy), embryos which were biopsied twice had lower OR for clinical pregnancy (0.48, CI 0.26-0.88, p = 0.019) and for live birth (0.50 CI 0.27-0.92, p = 0.025) compared to controls. Embryos which were biopsied once but vitrified twice had no different ORs for all reproductive outcomes compared to controls. No significant difference was observed for neonatal birthweight or sex ratio amongst the three groups. This is a retrospective single centre study with inherent bias and results may not be transferable to all settings., Conclusion: This study is the largest to date assessing the outcomes of FTET cycles following double trophectoderm biopsy. The results are in keeping with the existing literature and can be incorporated into patient counselling. Whilst double biopsy seems to adversely impact LBR, it is only one of the many factors that can affect success rates. The subfertility background and embryo characteristics should not be overlooked. This study provides reassuring evidence since double biopsied embryos still result in live births with no difference in sex ratio or birthweight. However, long term follow up of the off-springs is lacking and should be reported in future studies., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: The authors work in a private clinic that offers fertility treatment including PGT-A and PGT-M/SR., (Copyright © 2024 Elsevier B.V. All rights reserved.)
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- 2024
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26. The definition of unexplained infertility: A systematic review.
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Raperport C, Desai J, Qureshi D, Rustin E, Balaji A, Chronopoulou E, Homburg R, Khan KS, and Bhide P
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- Female, Humans, Male, Infertility diagnosis, Infertility, Female diagnosis, Ovulation Detection methods, Semen Analysis methods
- Abstract
Background: There is no consensus on tests required to either diagnose unexplained infertility or use for research inclusion criteria. This leads to heterogeneity and bias affecting meta-analysis and best practice advice., Objectives: This systematic review analyses the variability of inclusion criteria applied to couples with unexplained infertility. We propose standardised criteria for use both in future research studies and clinical diagnosis., Search Strategy: CINAHL and MEDLINE online databases were searched up to November 2022 for all published studies recruiting couples with unexplained infertility, available in full text in the English language., Data Collection and Analysis: Data were collected in an Excel spreadsheet. Results were analysed per category and methodology or reference range., Main Results: Of 375 relevant studies, only 258 defined their inclusion criteria. The most commonly applied inclusion criteria were semen analysis, tubal patency and assessment of ovulation in 220 (85%), 232 (90%), 205 (79.5%) respectively. Only 87/220 (39.5%) studies reporting semen analysis used the World Health Organization (WHO) limits. Tubal patency was accepted if bilateral in 145/232 (62.5%) and if unilateral in 24/232 (10.3%). Ovulation was assessed using mid-luteal serum progesterone in 115/205 (56.1%) and by a history of regular cycles in 87/205 (42.4%). Other criteria, including uterine cavity assessment and hormone profile, were applied in less than 50% of included studies., Conclusions: This review highlights the heterogeneity among studied populations with unexplained infertility. Development and application of internationally accepted criteria will improve the quality of research and future clinical care., (© 2023 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd.)
- Published
- 2024
- Full Text
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27. Liver transplantation in ornithine transcarbamylase deficiency: A retrospective multicentre cohort study.
- Author
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Seker Yilmaz B, Baruteau J, Chakrapani A, Champion M, Chronopoulou E, Claridge LC, Daly A, Davies C, Davison J, Dhawan A, Grunewald S, Gupte GL, Heaton N, Lemonde H, McKiernan P, Mills P, Morris AAM, Mundy H, Pierre G, Rajwal S, Sivananthan S, Sreekantam S, Stepien KM, Vara R, Yeo M, and Gissen P
- Abstract
Ornithine transcarbamylase deficiency (OTCD) is an X-linked defect of ureagenesis and the most common urea cycle disorder. Patients present with hyperammonemia causing neurological symptoms, which can lead to coma and death. Liver transplantation (LT) is the only curative therapy, but has several limitations including organ shortage, significant morbidity and requirement of lifelong immunosuppression. This study aims to identify the characteristics and outcomes of patients who underwent LT for OTCD. We conducted a retrospective study for OTCD patients from 5 UK centres receiving LT in 3 transplantation centres between 2010 and 2022. Patients' demographics, family history, initial presentation, age at LT, graft type and pre- and post-LT clinical, metabolic, and neurocognitive profile were collected from medical records. A total of 20 OTCD patients (11 males, 9 females) were enrolled in this study. 6/20 had neonatal and 14/20 late-onset presentation. 2/20 patients had positive family history for OTCD and one of them was diagnosed antenatally and received prospective treatment. All patients were managed with standard of care based on protein-restricted diet, ammonia scavengers and supplementation with arginine and/or citrulline before LT. 15/20 patients had neurodevelopmental problems before LT. The indication for LT was presence (or family history) of recurrent metabolic decompensations occurring despite standard medical therapy leading to neurodisability and quality of life impairment. Median age at LT was 10.5 months (6-24) and 66 months (35-156) in neonatal and late onset patients, respectively. 15/20 patients had deceased donor LT (DDLT) and 5/20 had living related donor LT (LDLT). Overall survival was 95% with one patient dying 6 h after LT. 13/20 had complications after LT and 2/20 patients required re-transplantation. All patients discontinued dietary restriction and ammonia scavengers after LT and remained metabolically stable. Patients who had neurodevelopmental problems before LT persisted to have difficulties after LT. 1/5 patients who was reported to have normal neurodevelopment before LT developed behavioural problems after LT, while the remaining 4 maintained their abilities without any reported issues. LT was found to be effective in correcting the metabolic defect, eliminates the risk of hyperammonemia and prolongs patients' survival., Competing Interests: PG is an academic co-founder of Bloomsbury Genetic Therapies, UCL spinout developing a gene programme in OTC deficiency. JB receives research funding from Moderna Therapeutics, developing gene therapy for urea cycle defects., (© 2023 The Authors.)
- Published
- 2023
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28. Correction to: Endogenous progesterone in unexplained infertility: a systematic review and meta‑analysis.
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Raperport C, Chronopoulou E, Homburg R, Khan K, and Bhide P
- Published
- 2023
- Full Text
- View/download PDF
29. Endogenous progesterone in unexplained infertility: a systematic review and meta-analysis.
- Author
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Raperport C, Chronopoulou E, Homburg R, Khan K, and Bhide P
- Subjects
- Female, Humans, Endometrium metabolism, Corpus Luteum metabolism, Progesterone, Infertility, Female etiology
- Abstract
Purpose: To investigate the possibility that altered actions of endogenous progesterone affect receptivity and contribute to unexplained infertility (UI)., Methods: Two authors electronically searched MEDLINE, CINAHL and Embase databases from inception to 6 July 2022 and hand-searched according to Cochrane methodology. We included all published primary research reporting outcomes related to endogenous progesterone in natural cycles in women with UI. Studies were assessed for risk of bias using a modified Newcastle-Ottawa Score or NHLBI Score. We pooled results where appropriate using a random-effects model. Findings were reported as odds ratios or mean differences., Results: We included 41 studies (n = 4023). No difference was found between the mid-luteal serum progesterone levels of women with UI compared to fertile controls (MD 0.74, - 0.31-1.79, I
2 36%). Women with UI had significantly higher rates of 'out-of-phase' endometrium than controls. Nine out of 10 progesterone-mediated markers of endometrial receptivity were significantly reduced in women with UI compared to fertile controls (the remaining 1 had conflicting results). Resistance in pelvic vessels was increased and perfusion of the endometrium and sub-endometrium reduced in UI compared to fertile controls in all included studies. Progesterone receptor expression and progesterone uptake were also reduced in women with unexplained infertility., Conclusions: End-organ measures of endogenous progesterone activity are reduced in women with UI compared to fertile controls. This apparently receptor-mediated reduction in response affects endometrial receptivity and is implicated as the cause of the infertility. Further research is required to confirm whether intervention could overcome this issue, offering a new option for treating unexplained infertility., Trial Registration: PROSPERO registration: CRD42020141041 06/08/2020., (© 2022. The Author(s).)- Published
- 2023
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30. EPH/Ephrin-Targeting Treatment in Breast Cancer: A New Chapter in Breast Cancer Therapy.
- Author
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Psilopatis I, Souferi-Chronopoulou E, Vrettou K, Troungos C, and Theocharis S
- Subjects
- Humans, Female, Receptors, Eph Family metabolism, Ephrin-B2 metabolism, Protein Binding, Membrane Proteins metabolism, Ephrins metabolism, Breast Neoplasms drug therapy
- Abstract
Breast cancer (BC) is the most common malignant tumor in women. Erythropoietin-producing hepatocellular receptors (EPHs), receptor tyrosine kinases binding the membrane-bound proteins ephrins, are differentially expressed in BC, and correlate with carcinogenesis and tumor progression. With a view to examining available therapeutics targeting the EPH/ephrin system in BC, a literature review was conducted, using the MEDLINE, LIVIVO, and Google Scholar databases. EPHA2 is the most studied EPH/ephrin target in BC treatment. The targeting of EPHA2, EPHA10, EPHB4, ephrin-A2, ephrin-A4, as well as ephrin-B2 in BC cells or xenograft models is associated with apoptosis induction, tumor regression, anticancer immune response activation, and impaired cell motility. In conclusion, EPHs/ephrins seem to represent promising future treatment targets in BC.
- Published
- 2022
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31. Three-Country Snapshot of Ornithine Transcarbamylase Deficiency.
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Seker Yilmaz B, Baruteau J, Arslan N, Aydin HI, Barth M, Bozaci AE, Brassier A, Canda E, Cano A, Chronopoulou E, Connolly GM, Damaj L, Dawson C, Dobbelaere D, Douillard C, Eminoglu FT, Erdol S, Ersoy M, Fang S, Feillet F, Gokcay G, Goksoy E, Gorce M, Inci A, Kadioglu B, Kardas F, Kasapkara CS, Kilic Yildirim G, Kor D, Kose M, Marelli C, Mundy H, O'Sullivan S, Ozturk Hismi B, Ramachandran R, Roubertie A, Sanlilar M, Schiff M, Sreekantam S, Stepien KM, Uzun Unal O, Yildiz Y, Zubarioglu T, and Gissen P
- Abstract
X-linked ornithine transcarbamylase deficiency (OTCD) is the most common urea cycle defect. The disease severity ranges from asymptomatic carrier state to severe neonatal presentation with hyperammonaemic encephalopathy. We audited the diagnosis and management of OTCD, using an online 12-question-survey that was sent to 75 metabolic centres in Turkey, France and the UK. Thirty-nine centres responded and 495 patients were reported in total. A total of 208 French patients were reported, including 71 (34%) males, 86 (41%) symptomatic and 51 (25%) asymptomatic females. Eighty-five Turkish patients included 32 (38%) males, 39 (46%) symptomatic and 14 (16%) asymptomatic females. Out of the 202 UK patients, 66 (33%) were male, 83 (41%) asymptomatic and 53 (26%) symptomatic females. A total of 19%, 12% and 7% of the patients presented with a neonatal-onset phenotype in France, Turkey and the UK, respectively. Vomiting, altered mental status and encephalopathy were the most common initial symptoms in all three countries. While 69% in France and 79% in Turkey were receiving protein restriction, 42% were on a protein-restricted diet in the UK. A total of 76%, 47% and 33% of patients were treated with ammonia scavengers in Turkey, France and the UK, respectively. The findings of our audit emphasize the differences and similarities in manifestations and management practices in three countries.
- Published
- 2022
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32. Wnt4, Wnt6 and β-catenin expression in human placental tissue - is there a link with first trimester miscarriage? Results from a pilot study.
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Chronopoulou E, Koika V, Tsiveriotis K, Stefanidis K, Kalogeropoulos S, Georgopoulos N, Adonakis G, and Kaponis A
- Subjects
- Adult, Cell Proliferation genetics, Female, Gene Expression Regulation, Developmental, Humans, Pilot Projects, Pregnancy, Trophoblasts cytology, Trophoblasts metabolism, Wnt Signaling Pathway genetics, Abortion, Spontaneous genetics, Placenta metabolism, Pregnancy Trimester, First genetics, Wnt Proteins genetics, Wnt4 Protein genetics, beta Catenin genetics
- Abstract
Background: Demystifying the events around early pregnancy is challenging. A wide network of mediators and signaling cascades orchestrate the processes of implantation and trophoblast proliferation. Dysregulation of these pathways could be implicated in early pregnancy loss. There is accumulating evidence around the role of Wnt pathway in implantation and early pregnancy. The purpose of this study was to explore alterations in the expression of Wnt4, Wnt6 and β-catenin in placental tissue obtained from human first trimester euploid miscarriages versus normally developing early pregnancies., Methods: The study group consisted of first trimester miscarriages (early embryonic demises and incomplete miscarriages) and the control group of social terminations of pregnancy (TOPs). The placental mRNA expression of Wnt4, Wnt6 and β-catenin was studied using reverse transcription PCR and real time PCR. Only euploid conceptions were included in the analysis., Results: Wnt4 expression was significantly increased in placental tissue from first trimester miscarriages versus controls (p = 0.003). No significant difference was documented in the expression of Wnt6 (p = 0.286) and β-catenin (p = 0.793). There was a 5.1fold increase in Wnt4 expression for early embryonic demises versus TOPs and a 7.6fold increase for incomplete miscarriages versus TOPs - no significant difference between the two subgroups of miscarriage (p = 0.533)., Conclusions: This is, to our knowledge, the first study demonstrating significant alteration of Wnt4 expression in human placental tissue, from failed early pregnancies compared to normal controls. Undoubtedly, a more profound study is needed to confirm these preliminary findings and explore Wnt mediators as potential targets for strategies to predict and prevent miscarriage., (© 2022. The Author(s).)
- Published
- 2022
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33. Clinical presentation and natural history of Barth Syndrome: An overview.
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Taylor C, Rao ES, Pierre G, Chronopoulou E, Hornby B, Heyman A, and Vernon HJ
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- Acyltransferases genetics, Barth Syndrome genetics, Barth Syndrome therapy, Cardiolipins metabolism, Cardiomyopathies metabolism, Cardiomyopathies pathology, Humans, Mitochondrial Membranes metabolism, Muscular Diseases metabolism, Muscular Diseases pathology, Mutation, Neutropenia metabolism, Neutropenia pathology, Barth Syndrome metabolism, Barth Syndrome pathology
- Abstract
Barth Syndrome is a rare X-linked disorder caused by pathogenic variants in the gene TAFAZZIN, which encodes for an enzyme involved in the remodeling of cardiolipin, a phospholipid primarily localized to the inner mitochondrial membrane. Barth Syndrome is characterized by cardiomyopathy, skeletal myopathy, neutropenia, and growth abnormalities, among other features. In this review, we will discuss the clinical presentation and natural history of Barth Syndrome, review key features of this disease, and introduce less common clinical associations. Recognition and understanding of the natural history of Barth Syndrome are important for ongoing patient management and developing endpoints for the demonstration of efficacy of new and emerging therapies., (© 2021 SSIEM.)
- Published
- 2022
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34. Effects of metformin treatment on pregnancy outcomes in patients with polycystic ovary syndrome.
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Raperport C, Chronopoulou E, and Homburg R
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- Female, Humans, Hypoglycemic Agents therapeutic use, Live Birth, Pregnancy, Pregnancy Outcome, Pregnancy Rate, Metformin therapeutic use, Polycystic Ovary Syndrome drug therapy
- Abstract
Introduction: This review covers the current evidence regarding the use of metformin as a therapeutic intervention for optimizing pregnancy outcomes in women with polycystic ovary syndrome (PCOS)., Areas Covered: After searching Medline, Embase and CINAHL, all important large clinical trials and observational studies plus systematic reviews, meta-analyses and Cochrane reviews have been summarized here. The results have been compared to culminate in a thorough review and discussion on the use of metformin in relation to reproductive outcomes for women with PCOS. The role of metformin in PCOS is explored both in terms of achieving conception and during pregnancy. The existing evidence around metformin use is summarized both during the preconceptual period and during pregnancy, in relation to reproductive outcomes., Expert Opinion: Metformin is a widely used medication, often prescribed to improve reproductive outcomes for women with PCOS. However, the evidence remains equivocal regarding its efficacy both in optimizing fertility and pregnancy outcomes. More research is required with special emphasis on metformin use within different populations, including ethnic groups and women with varying BMI ranges.
- Published
- 2021
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35. Preconception tests at advanced maternal age.
- Author
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Chronopoulou E, Raperport C, Serhal P, Saab W, and Seshadri S
- Subjects
- Aged, Female, Humans, Maternal Age, Pregnancy, Risk Factors, Preconception Care, Pregnancy Complications diagnosis
- Abstract
Pregnancies at an advanced reproductive age are increasingly common. However, the safety of pregnancy remains a concern as maternal age is a recognized independent factor for various obstetric complications. Also, age is a risk factor for most systematic health problems and older women are more likely to enter into pregnancy with pre-existing conditions. At the moment there is no separate, structured guidance on preconception tests at advanced maternal age. However, the preconceptual period offers an ideal window to recognize and address underlying health issues, social issues and harmful lifestyle behaviours in order to optimize maternal health ultimately reducing infertility, perinatal morbidity and mortality. Preconception tests should be clinically relevant aiming to identify risk factors and address them to predict and prevent infertility and pregnancy complications. The importance of preconception care is magnified for women of advanced age for whom the risks are higher and the potential benefits greater., Competing Interests: Declaration of competing interest The authors report no conflict of interest., (Copyright © 2020. Published by Elsevier Ltd.)
- Published
- 2021
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36. Capecitabine, Oxaliplatin, Irinotecan, and Bevacizumab Combination Followed by Pazopanib Plus Capecitabine Maintenance for High-Grade Gastrointestinal Neuroendocrine Carcinomas.
- Author
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Alifieris CE, Griniatsos J, Delis SG, Nikolaou M, Avgoustou C, Panagiotidis MI, Souferi-Chronopoulou E, and Trafalis DT
- Subjects
- Adult, Aged, Bevacizumab administration & dosage, Bevacizumab adverse effects, Capecitabine administration & dosage, Capecitabine adverse effects, Carcinoma, Neuroendocrine mortality, Female, Gastrointestinal Neoplasms mortality, Humans, Indazoles, Irinotecan administration & dosage, Irinotecan adverse effects, Male, Middle Aged, Oxaliplatin administration & dosage, Oxaliplatin adverse effects, Progression-Free Survival, Pyrimidines administration & dosage, Pyrimidines adverse effects, Sulfonamides administration & dosage, Sulfonamides adverse effects, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Carcinoma, Neuroendocrine drug therapy, Gastrointestinal Neoplasms drug therapy
- Abstract
Objectives: Gastrointestinal neuroendocrine carcinoma (NEC) is a lethal, uncommon, and understudied neoplasm. We present the efficacy and safety of first-line capecitabine (CP), oxaliplatin, irinotecan, and bevacizumab (CAPOXIRI-BEV) combination followed by pazopanib plus CP maintenance therapy in patients with advanced high-grade poorly differentiated gastrointestinal NEC., Methods: This was a two-stage phase II study conducted at multiple institutions. Patients were consecutively enrolled and had advanced NEC of the colon or small bowel. Patients received irinotecan 125 mg/m, oxaliplatin 80 mg/m on day 1, CP 1000 mg/m twice daily on days 1 to 14, plus bevacizumab 8 mg/kg on day 1 for six 21-day cycles. Maintenance therapy was given to those who responded (complete response/partial response) or had stable disease after 6 cycles with CAPOXIRI-BEV with pazopanib 800 mg daily plus CP 1600 mg/m daily on days 1 to 14 every 3 weeks until disease progression or unacceptable toxicity. Patients who progressed on CAPOXIRI-BEV received standard etoposide-carboplatin. The primary endpoint was overall response rate., Results: Twenty-two patients were enrolled of whom 19 were evaluable. The median age was 60 years. The overall response rate (3 complete response/6 partial response) was 47.4% (95% confidence interval: 29.5-76.1), the overall disease control rate was 78.9% (95% confidence interval: 62.6-99.6), and, at median 30 (11 to 41 mo) months' follow-up, 5 patients (26.3%) were still alive. Median progression-free survival was 13 months, and the 1-year progression-free survival rate was 52.6%. The median overall survival was 29 months. The median overall survival of the 9 patients who responded versus those with stable disease/progressive disease was 30.5 versus 14 months, respectively. The median duration of response was 16 months. Predictable toxicity was observed., Conclusions: First-line CAPOXIRI-BEV followed by pazopanib plus CP maintenance therapy for advanced NEC demonstrates promising efficacy and predictable toxicity. Further investigation is warranted.
- Published
- 2020
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37. Clinical presentation and proteomic signature of patients with TANGO2 mutations.
- Author
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Mingirulli N, Pyle A, Hathazi D, Alston CL, Kohlschmidt N, O'Grady G, Waddell L, Evesson F, Cooper SBT, Turner C, Duff J, Topf A, Yubero D, Jou C, Nascimento A, Ortez C, García-Cazorla A, Gross C, O'Callaghan M, Santra S, Preece MA, Champion M, Korenev S, Chronopoulou E, Anirban M, Pierre G, McArthur D, Thompson K, Navas P, Ribes A, Tort F, Schlüter A, Pujol A, Montero R, Sarquella G, Lochmüller H, Jiménez-Mallebrera C, Taylor RW, Artuch R, Kirschner J, Grünert SC, Roos A, and Horvath R
- Subjects
- Brain Diseases, Metabolic diagnosis, Fatty Acids metabolism, Female, Golgi Apparatus genetics, Golgi Apparatus metabolism, Homozygote, Humans, Infant, Male, Mitochondrial Diseases diagnosis, Oxidative Phosphorylation, Phenotype, Rhabdomyolysis diagnosis, Whole Genome Sequencing, Brain Diseases, Metabolic genetics, Mitochondrial Diseases genetics, Muscle Weakness genetics, Mutation, Proteomics methods, Rhabdomyolysis genetics
- Abstract
Transport And Golgi Organization protein 2 (TANGO2) deficiency has recently been identified as a rare metabolic disorder with a distinct clinical and biochemical phenotype of recurrent metabolic crises, hypoglycemia, lactic acidosis, rhabdomyolysis, arrhythmias, and encephalopathy with cognitive decline. We report nine subjects from seven independent families, and we studied muscle histology, respiratory chain enzyme activities in skeletal muscle and proteomic signature of fibroblasts. All nine subjects carried autosomal recessive TANGO2 mutations. Two carried the reported deletion of exons 3 to 9, one homozygous, one heterozygous with a 22q11.21 microdeletion inherited in trans. The other subjects carried three novel homozygous (c.262C>T/p.Arg88*; c.220A>C/p.Thr74Pro; c.380+1G>A), and two further novel heterozygous (c.6_9del/p.Phe6del); c.11-13delTCT/p.Phe5del mutations. Immunoblot analysis detected a significant decrease of TANGO2 protein. Muscle histology showed mild variation of fiber diameter, no ragged-red/cytochrome c oxidase-negative fibers and a defect of multiple respiratory chain enzymes and coenzyme Q
10 (CoQ10 ) in two cases, suggesting a possible secondary defect of oxidative phosphorylation. Proteomic analysis in fibroblasts revealed significant changes in components of the mitochondrial fatty acid oxidation, plasma membrane, endoplasmic reticulum-Golgi network and secretory pathways. Clinical presentation of TANGO2 mutations is homogeneous and clinically recognizable. The hemizygous mutations in two patients suggest that some mutations leading to allele loss are difficult to detect. A combined defect of the respiratory chain enzymes and CoQ10 with altered levels of several membrane proteins provides molecular insights into the underlying pathophysiology and may guide rational new therapeutic interventions., (© 2019 The Authors. Journal of Inherited Metabolic Disease published by John Wiley & Sons Ltd on behalf of SSIEM.)- Published
- 2020
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38. The arbitrary magic of p<0.05: Beyond statistics.
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E Alifieris C, Souferi Chronopoulou E, T Trafalis D, and Arvelakis A
- Subjects
- Humans, Peer Review methods, Peer Review standards, Publications standards, Biostatistics methods
- Abstract
Modern research and scientific conclusions are widely regarded as valid when the study design and analysis are interpreted correctly. P-value is considered to be the most commonly used method to provide a dichotomy between true and false data in evidence-based medicine. However, many authors, reviewers and editors may be unfamiliar with the true definition and correct interpretation of this number. This article intends to point out how misunderstanding or misuse of this value can have an impact in both the scientific community as well as the society we live in. The foundation of the medical education system rewards the abundance of scientific papers rather than the careful search of the truth. Appropriate research ethics should be practised in all stages of the publication process.
- Published
- 2020
39. Tolerance of Transplastomic Tobacco Plants Overexpressing a Theta Class Glutathione Transferase to Abiotic and Oxidative Stresses.
- Author
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Stavridou E, Michailidis M, Gedeon S, Ioakeim A, Kostas S, Chronopoulou E, Labrou NE, Edwards R, Day A, Nianiou-Obeidat I, and Madesis P
- Abstract
Chloroplasts are organelles subjected to extreme oxidative stress conditions. Biomolecules produced in the chloroplasts act as signals guiding plant metabolism toward stress tolerance and play a major role in regulating gene expression in the nucleus. Herein, we used transplastomic plants as an alternative approach to expression of transgenes in the nucleus for conferring stress tolerance to abiotic stresses and herbicides. To investigate the morphophysiological and molecular mechanisms and the role of plastid expressed GSTs in tobacco stress detoxification and stress tolerance, we used transplastomic tobacco lines overexpressing a theta class glutathione transferase (GST) in chloroplasts. The transplastomic plants were tested under drought (0, 100, and 200 mM mannitol) and salinity (0, 150, and 300 mM NaCl) in vitro , and under herbicide stress (Diquat). Our results suggest that pt
At GSTT lines were tolerant to herbicide-induced oxidative and salinity stresses and showed enhanced response tolerance to mannitol-induced osmotic stress compared to WT plants. Overexpression of the Arabidopsis thaliana At GSTT in the chloroplasts resulted in enhanced photo-tolerance and turgor maintenance under stress. Whole-genome transcriptome analysis revealed that genes related to stress tolerance, were upregulated in ptAt GSTT 2a line under both control and high mannitol stress conditions. Transplastomic plants overexpressing the ptAt GSTT 2a in the chloroplast showed a state of acclimation to stress, as only limited number of genes were upregulated in the ptAt GSTT 2a transplastomic line compared to WT under stress conditions while at the same time genes related to stress tolerance were upregulated in ptAt GSTT 2a plants compared to WT in stress-free conditions. In parallel, the metabolic profile indicated limited perturbations of the metabolic homeostasis in the transplastomic lines and greater accumulation of mannitol, and soluble sugars under high mannitol stress. Therefore, transplastomic lines seem to be in a state of acclimation to stress under stress-free conditions, which was maintained even under high mannitol stress. The results help to elucidate the role of GSTs in plant abiotic stress tolerance and the underlying mechanisms of the GSTs expressed in the chloroplast, toward environmental resilience of cultivated crops.- Published
- 2019
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40. Delineation of the functional and structural properties of the glutathione transferase family from the plant pathogen Erwinia carotovora.
- Author
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Theoharaki C, Chronopoulou E, Vlachakis D, Ataya FS, Giannopoulos P, Maurikou S, Skopelitou K, Papageorgiou AC, and Labrou NE
- Subjects
- Bacterial Proteins genetics, Bacterial Proteins metabolism, Erwinia genetics, Glutathione Transferase genetics, Glutathione Transferase metabolism, Phylogeny, Protein Conformation, Bacterial Proteins chemistry, Erwinia enzymology, Glutathione Transferase chemistry
- Abstract
Erwinia carotovora, a widespread plant pathogen that causes soft rot disease in many plants, is considered a major threat in agriculture. Bacterial glutathione transferases (GSTs) play important roles in a variety of metabolic pathways and processes, such as the biodegradation of xenobiotics, protection against abiotic stress, and resistance against antimicrobial drugs. The GST family of canonical soluble enzymes from Erwinia carotovora subsp. atroseptica strain SCRI1043 (EcaGSTs) was investigated. Genome analysis showed the presence of six putative canonical cytoplasmic EcaGSTs, which were revealed by phylogenetic analysis to belong to the well-characterized GST classes beta, nu, phi, and zeta. The analysis also revealed the presence of two isoenzymes that were phylogenetically close to the omega class of GSTs, but formed a distinct class. The EcaGSTs were cloned and expressed in Escherichia coli, and their catalytic activity toward different electrophilic substrates was elucidated. The EcaGSTs catalyzed different types of reactions, although all enzymes were particularly active in reactions involving electrophile substitution. Gene and protein expression profiling conducted under normal culture conditions as well as in the presence of the herbicide alachlor and the xenobiotic 1-chloro-2,4-dinitrobenzene (CDNB) showed that the isoenzyme EcaGST1, belonging to the omega-like class, was specifically induced at both the protein and mRNA levels. EcaGST1 presumably participates in counteracting the xenobiotic toxicity and/or abiotic stress conditions, and may therefore represent a novel molecular target in the development of new chemical treatments to control soft rot diseases.
- Published
- 2019
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41. The curious case of premature luteinization.
- Author
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Kaponis A, Chronopoulou E, and Decavalas G
- Subjects
- Chorionic Gonadotropin therapeutic use, Female, Humans, Ovulation Induction adverse effects, Pregnancy, Pregnancy Rate, Premature Birth, Fertilization in Vitro, Gonadotropin-Releasing Hormone metabolism, Luteinization, Progesterone metabolism
- Abstract
Purpose: Premature luteinization (PL) affects 12.3-46.7% of fresh in vitro fertilization cycles, and there is accumulating evidence confirming its negative effect on success rates. However, despite its clinical significance, PL is poorly understood and defined. This narrative review aims to provide a fresh look at the phenomenon of PL by summarizing the existing evidence and re-evaluating fundamental issues., Methods: A thorough electronic search was conducted covering the period from 1978 until January 2018 in PubMed, Embase, and Medline databases, and references of relevant studies were cross-checked. Meeting proceedings of the European Society of Human Reproduction and Embryology and the American Society for Reproductive Medicine were also hand searched., Results: In the curious case of PL, one should go back to the beginning and re-consider every step of the way. The pathogenesis, definition, measurement methods, clinical implications, and management strategies are discussed in detail, highlighting controversies and offering "food for thought" for future directions., Conclusions: Authors need to speak the same language when studying PL in order to facilitate comparisons. The terminology, progesterone cut-off, measurement methods and days of measurement should be standardized and globally accepted; otherwise, there can be no scientific dialog. Future research should focus on specific patient profiles that may require a tailored approach. Progesterone measurements throughout the follicular phase possibly depict the progesterone exposure better than an isolated measurement on the day of hCG. Adequately powered randomized controlled trials should confirm which the best prevention and management plan of PL is, before introducing any strategy into clinical practice.
- Published
- 2018
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42. A toddler with worsening gait and leopard skin sign on MRI.
- Author
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Ghani S, Williams T, Likeman M, and Chronopoulou E
- Abstract
Competing Interests: Competing interests: None declared.
- Published
- 2018
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43. MT-ND5 Mutation Exhibits Highly Variable Neurological Manifestations at Low Mutant Load.
- Author
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Ng YS, Lax NZ, Maddison P, Alston CL, Blakely EL, Hepplewhite PD, Riordan G, Meldau S, Chinnery PF, Pierre G, Chronopoulou E, Du A, Hughes I, Morris AA, Kamakari S, Chrousos G, Rodenburg RJ, Saris CGJ, Feeney C, Hardy SA, Sakakibara T, Sudo A, Okazaki Y, Murayama K, Mundy H, Hanna MG, Ohtake A, Schaefer AM, Champion MP, Turnbull DM, Taylor RW, Pitceathly RDS, McFarland R, and Gorman GS
- Subjects
- Adolescent, Adult, Brain diagnostic imaging, Child, Cohort Studies, Female, Humans, Magnetic Resonance Imaging, Male, Syndrome, Young Adult, Brain pathology, Electron Transport Complex I genetics, Mitochondrial Proteins genetics, Mutation genetics
- Abstract
Mutations in the m.13094T>C MT-ND5 gene have been previously described in three cases of Leigh Syndrome (LS). In this retrospective, international cohort study we identified 20 clinically affected individuals (13 families) and four asymptomatic carriers. Ten patients were deceased at the time of analysis (median age of death was 10years (range: 5·4months-37years, IQR=17·9years). Nine patients manifested with LS, one with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS), and one with Leber hereditary optic neuropathy. The remaining nine patients presented with either overlapping syndromes or isolated neurological symptoms. Mitochondrial respiratory chain activity analysis was normal in five out of ten muscle biopsies. We confirmed maternal inheritance in six families, and demonstrated marked variability in tissue segregation, and phenotypic expression at relatively low blood mutant loads. Neuropathological studies of two patients manifesting with LS/MELAS showed prominent capillary proliferation, microvacuolation and severe neuronal cell loss in the brainstem and cerebellum, with conspicuous absence of basal ganglia involvement. These findings suggest that whole mtDNA genome sequencing should be considered in patients with suspected mitochondrial disease presenting with complex neurological manifestations, which would identify over 300 known pathogenic variants including the m.13094T>C., (Copyright © 2018 German Center for Neurodegenerative Diseases (DZNE). Published by Elsevier B.V. All rights reserved.)
- Published
- 2018
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44. Structure-based design and application of a nucleotide coenzyme mimetic ligand: Application to the affinity purification of nucleotide dependent enzymes.
- Author
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Marinou M, Platis D, Ataya FS, Chronopoulou E, Vlachakis D, and Labrou NE
- Subjects
- Adsorption, Binding Sites, Biomimetics, Chromatography, Affinity methods, Coenzymes chemistry, Coenzymes metabolism, Formate Dehydrogenases metabolism, Molecular Conformation, Molecular Docking Simulation, Mutagenesis, Site-Directed, Sepharose, Enzymes isolation & purification, Ligands, Models, Molecular, Nucleotides chemistry
- Abstract
In the present study, a structure-based approach was exploited for the in silico design of a nucleotide coenzyme mimetic ligand. The enzyme formate dehydrogenase (FDH) was employed as a model in our study. The biomimetic ligand was designed and synthesized based on a tryptamine/3-aminopropylphosphonic acid bi-substituted 1,3,5-triazine (Trz) scaffold (Tra-Trz-3APP), which potentially mimics the interactions of NAD
+ -FDH complex. Molecular docking studies of the biomimetic ligand predicted that it can occupy the same binding site as the natural coenzyme. Molecular modeling and dynamics simulations revealed that the ligand binds in an energetically more stable pose in the FDH binding site, as it adopts a more twisty conformation, compared to the natural coenzyme. Study of the FDH/Tra-Trz-3APP-Sepharose interaction, through adsorption equilibrium studies and site-directed mutagenesis of selected FDH coenzyme binding residues, provided additional experimental evidences of the specificity of the interaction. The Tra-Trz-3APP-Sepharose biomimetic adsorbent was further evaluated towards a range of different dehydrogenases and was exploited for the development of a single-step purification protocol for FDH. The protocol afforded enzyme with high yield and purity, suitable for analytical and industrial purposes., (Copyright © 2018 Elsevier B.V. All rights reserved.)- Published
- 2018
- Full Text
- View/download PDF
45. Plant glutathione transferase-mediated stress tolerance: functions and biotechnological applications.
- Author
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Nianiou-Obeidat I, Madesis P, Kissoudis C, Voulgari G, Chronopoulou E, Tsaftaris A, and Labrou NE
- Subjects
- Biodegradation, Environmental, Plant Growth Regulators metabolism, Biotechnology methods, Glutathione Transferase metabolism
- Abstract
Plant glutathione transferases (EC 2.5.1.18, GSTs) are an ancient, multimember and diverse enzyme class. Plant GSTs have diverse roles in plant development, endogenous metabolism, stress tolerance, and xenobiotic detoxification. Their study embodies both fundamental aspects and agricultural interest, because of their ability to confer tolerance against biotic and abiotic stresses and to detoxify herbicides. Here we review the biotechnological applications of GSTs towards developing plants that are resistant to biotic and abiotic stresses. We integrate recent discoveries, highlight, and critically discuss the underlying biochemical and molecular pathways involved. We elaborate that the functions of GSTs in abiotic and biotic stress adaptation are potentially a result of both catalytic and non-catalytic functions. These include conjugation of reactive electrophile species with glutathione and the modulation of cellular redox status, biosynthesis, binding, and transport of secondary metabolites and hormones. Their major universal functions under stress underline the potential in developing climate-resilient cultivars through a combination of molecular and conventional breeding programs. We propose that future GST engineering efforts through rational and combinatorial approaches, would lead to the design of improved isoenzymes with purpose-designed catalytic activities and novel functional properties. Concurrent GST-GSH metabolic engineering can incrementally increase the effectiveness of GST biotechnological deployment.
- Published
- 2017
- Full Text
- View/download PDF
46. Functional and Catalytic Characterization of the Detoxifying Enzyme Haloalkane Dehalogenase from Rhizobium leguminosarum.
- Author
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Georgakis N, Chronopoulou E, Gad MA, Skliros D, Efrose R, Flemetakis E, and Labrou NE
- Subjects
- Binding Sites, Catalytic Domain, Crystallography, X-Ray, Environmental Restoration and Remediation, Escherichia coli genetics, Gene Expression Regulation, Enzymologic drug effects, Hydrocarbons, Brominated chemistry, Hydrocarbons, Brominated toxicity, Hydrolases chemistry, Hydrolases genetics, Models, Molecular, Phylogeny, Protein Folding, Rhizobium leguminosarum chemistry, Substrate Specificity, Catalysis, Hydrolases metabolism, Rhizobium leguminosarum enzymology
- Abstract
Background: Haloalkane dehalogenases (EC 3.8.1.5, HLDs) are α/β-hydrolases which catalyze the irreversible cleavage of carbon-halogen bonds of haloalkanes, producing an alcohol, a halide and a hydrogen ion. Haloalkanes are acutely toxic to animals and humans and their toxic effects are mainly observed in the liver, kidneys and central nervous system., Objective: In the present work, the haloalkane dehalogenase from Rhizobium leguminosarum bv. trifolii (DrlA) was characterized., Method: Reverse transcription polymerase chain reaction analysis and enzyme activity assays revealed that the DrlA gene expression in R. leguminosarum bv. trifolii is induced by 1,2- dibromoethane (1,2-DBE) during the early exponential phase. The gene of the enzyme was isolated, cloned and expressed in E. coli Rosetta (DE3)., Results: Recombinant DrlA displays its high catalytic activity towards 1,2-DBE and the long-chain haloalkane 1-iodohexane. Limited activity was observed for other aliphatic and cyclic haloalkanes, indicating that the enzyme displays restricted substrate specificity, compared to other bacterial HLDs. Homology modelling and phylogenetic analysis suggested that the enzyme belongs to the HLD-II subfamily and shares the same overall fold and domain organization as other bacterial HLDs, however major variations were identified at the hydrophobic substrate-binding cavity, the cap domain and the entrance of the main tunnel that affect the size of the active site pocket and the substrate recognition mechanism., Conclusion: This work sheds new light on the environmental fate and toxicity of 1,2-DBE and provides new knowledge on the structure, function and diversity of HLDs for developing applications in toxicology., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)
- Published
- 2017
- Full Text
- View/download PDF
47. Catalytic features and crystal structure of a tau class glutathione transferase from Glycine max specifically upregulated in response to soybean mosaic virus infections.
- Author
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Skopelitou K, Muleta AW, Papageorgiou AC, Chronopoulou E, and Labrou NE
- Subjects
- Binding Sites, Catalytic Domain, Crystallography, X-Ray, Gene Expression Regulation, Plant genetics, Glutathione Transferase genetics, Kinetics, Protein Structure, Secondary, Glycine max genetics, Stress, Physiological, Substrate Specificity, Transcriptional Activation, Glutathione Transferase biosynthesis, Glutathione Transferase chemistry, Mosaic Viruses pathogenicity, Glycine max enzymology
- Abstract
The plant tau class glutathione transferases (GSTs) play important roles in biotic and abiotic stress tolerance in crops and weeds. In this study, we systematically examined the catalytic and structural features of a GST isoenzyme from Glycine max (GmGSTU10-10). GmGSTU10-10 is a unique isoenzyme in soybean that is specifically expressed in response to biotic stress caused by soybean mosaic virus (SMV) infections. GmGSTU10-10 was cloned, expressed in Escherichia coli, purified and characterized. The results showed that GmGSTU10-10 catalyzes several different reactions and exhibits wide substrate specificity. Of particular importance is the finding that the enzyme shows high antioxidant catalytic function and acts as hydroperoxidase. In addition, its Km for GSH is significantly lower, compared to other plant GSTs, suggesting that GmGSTU10-10 is able to perform efficient catalysis under conditions where the concentration of reduced glutathione is low (e.g. oxidative stress). The crystal structure of GmGSTU10-10 was solved by molecular replacement at 1.6Å resolution in complex with glutathione sulfenic acid (GSOH). Structural analysis showed that GmGSTU10-10 shares the same overall fold and domain organization as other plant cytosolic GSTs; however, major variations were identified in helix H9 and the upper part of helix H4 that affect the size of the active site pockets, substrate recognition and the catalytic mechanism. The results of the present study provide new information into GST diversity and give further insights into the complex regulation and enzymatic functions of this plant gene superfamily., (Copyright © 2014 Elsevier B.V. All rights reserved.)
- Published
- 2015
- Full Text
- View/download PDF
48. IVF culture media: past, present and future.
- Author
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Chronopoulou E and Harper JC
- Subjects
- Animals, Embryonic Development, Europe, History, 20th Century, History, 21st Century, Humans, Intercellular Signaling Peptides and Proteins metabolism, Reproductive Techniques, Assisted, Culture Media chemistry, Culture Media history, Embryo Culture Techniques history, Fertilization in Vitro history
- Abstract
Background: The advances in the world of IVF during the last decades have been rapid and impressive and culture media play a major role in this success. Until the 1980s fertility centers made their media in house. Nowadays, there are numerous commercially available culture media that contain various components including nutrients, vitamins and growth factors. This review goes through the past, present and future of IVF culture media and explores their composition and quality assessment., Methods: A computerized search was performed in PubMed regarding IVF culture media including results from 1929 until March 2014. Information was gathered from the websites of companies who market culture media, advertising material, instructions for use and certificates of analysis. The regulation regarding IVF media mainly in the European Union (EU) but also in non-European countries was explored., Results: The keyword 'IVF culture media' gave 923 results in PubMed and 'embryo culture media' 12 068 results dating from 1912 until March 2014, depicting the increased scientific activity in this field. The commercialization of IVF culture media has increased the standards bringing a great variety of options into clinical practice. However, it has led to reduced transparency and comparisons of brand names that do not facilitate the scientific dialogue. Furthermore, there is some evidence suggesting that suboptimal culture conditions could cause long-term reprogramming in the embryo as the periconception period is particularly susceptible to epigenetic alterations. IVF media are now classified as class III medical devices and only CE (Conformité Européene)-marked media should be used in the EU., Conclusion: The CE marking of IVF culture media is a significant development in the field. However, the quality and efficiency of culture media should be monitored closely. Well-designed randomized controlled trials, large epidemiological studies and full transparency should be the next steps. Reliable, standardized models assessing multiple end-points and post-implantation development should replace the mouse embryo assay. Structured long-term follow-up of children conceived by assisted reproduction technologies and traceability are of paramount importance., (© The Author 2014. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)
- Published
- 2015
- Full Text
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49. Screening hybridomas for cell surface antigens by high-throughput homogeneous assay and flow cytometry.
- Author
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Uribe-Benninghoff A, Cabral T, Chronopoulou E, Berry JD, and Corbett CR
- Subjects
- Antigens, Surface genetics, Flow Cytometry, Antigens, Surface metabolism, Hybridomas metabolism
- Abstract
Described herein are methods for the successful screening of monoclonal antibodies (mAbs) of the desired specificities via high-throughput (HTP) homogeneous assay and flow cytometry. We present a combination of screening techniques that allow the scientist to efficiently eliminate nontarget-specific antibody as soon as possible. This compilation of protocols will enable researchers with basic immunology skills to make decisions regarding the design of screening algorithms for the generation of mAbs. Although we have provided an informative overview of both HTP homogeneous assay and flow cytometry, it is imperative for the beginner to acquire fundamental knowledge on how both of these technologies work so as to use these screening strategies effectively.
- Published
- 2014
- Full Text
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50. Cloning and characterization of a biotic-stress-inducible glutathione transferase from Phaseolus vulgaris.
- Author
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Chronopoulou E, Madesis P, Tsaftaris A, and Labrou NE
- Subjects
- Amino Acid Sequence, Binding Sites, Cloning, Molecular, Computational Biology, Dinitrochlorobenzene metabolism, Electrophoresis, Polyacrylamide Gel, Glutathione metabolism, Glutathione Transferase chemistry, Kinetics, Models, Molecular, Molecular Sequence Data, Phaseolus drug effects, Protein Structure, Secondary, Recombinant Proteins metabolism, Sequence Alignment, Sequence Analysis, Protein, Substrate Specificity drug effects, Xenobiotics pharmacology, Glutathione Transferase biosynthesis, Phaseolus enzymology, Stress, Physiological drug effects
- Abstract
Glutathione transferases (GSTs, EC 2.5.1.18) are ubiquitous proteins in plants that play important roles in stress tolerance and in the detoxification of toxic chemicals and metabolites. In this study, we systematically examined the catalytic diversification of a GST isoenzyme from Phaseolus vulgaris (PvGST) which is induced under biotic stress treatment (Uromyces appendiculatus infection). The full-length cDNA of this GST isoenzyme (termed PvGSTU3-3) with complete open reading frame, was isolated using RACE-RT and showed that the deduced amino acid sequence shares high homology with the tau class plant GSTs. PvGSTU3-3 catalyzes several different reactions and exhibits wide substrate specificity. Of particular importance is the finding that the enzyme shows high antioxidant catalytic function and acts as hydroperoxidase, thioltransferase, and dehydroascorbate reductase. In addition, its K m for GSH is about five to ten times lower compared to other plant GSTs, suggesting that PvGSTU3-3 is able to perform efficient catalysis under conditions where the concentration of reduced glutathione is low (e.g., oxidative stress). Its ability to conjugate GSH with isothiocyanates may provide an additional role for this enzyme to act as a regulator of the released isothiocyanates from glucosinolates as a response of biotic stress. Molecular modeling showed that PvGSTU3-3 shares the same overall fold and structural organization with other plant cytosolic GSTs, with major differences at their hydrophobic binding sites (H-sites) and some differences at the level of C-terminal domain and the linker between the C- and N-terminal domains. PvGSTU3-3, in general, exhibits restricted ability to bind xenobiotics in a nonsubstrate manner, suggesting that the biological role of PvGSTU3-3, is restricted mainly to the catalytic function. Our findings highlight the functional and catalytic diversity of plant GSTs and demonstrate their pivotal role for addressing biotic stresses in Phaseolus vulgaris.
- Published
- 2014
- Full Text
- View/download PDF
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