24 results on '"Apostolopoulou D"'
Search Results
2. Distributed Optimal Power Flow for Unbalanced Radial Systems with Time-varying Communication
- Author
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Apostolopoulou, D., Poudineh, R., and Sen, A.
- Subjects
TK - Abstract
This paper proposes a distributed multi-period optimal power flow (OPF) formulation for unbalanced three-phase radial distribution systems over time-varying communication networks. To this end, we model the three-phase unbalanced network, distributed generators (DG), and electric vehicles’ (EV) behaviour with inter-temporal constraints. Moreover, we represent the objectives of the distribution system operator and those of prosumers, e.g., who wish to minimise the cost of DG or the degradation cost of the EV batteries. We first formulate the centralised OPF that requires knowledge of DG costs; EV information in terms of desired energy, departure and arrival times that prosumers are reluctant in providing. Moreover, the computational effort required to solve the centralised OPF in cases of numerous DGs and EVs is very intensive. As such, we propose a distributed solution of the OPF over a time-varying communication network. We illustrate the proposed framework through a 33-bus distribution feeder.
- Published
- 2021
3. Clustering Sensitivity Analysis for Gaussian Process Regression Based Solar Output Forecast
- Author
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Najibi, F., Apostolopoulou, D., and Alonso, E.
- Subjects
QA75 ,GE ,Computer science ,business.industry ,TK ,Photovoltaic system ,Weather forecasting ,computer.software_genre ,Renewable energy ,Electric power system ,symbols.namesake ,Statistics ,symbols ,business ,Cluster analysis ,computer ,Gaussian process ,Solar power ,Test data - Abstract
Power system operations are becoming more challenging with the increasing penetration of renewable-based re- sources such as photovoltaic (PV) generation. In this regard, obtaining accurate solar power output forecasts allows a deepening penetration of renewable-based resources in a secure and reliable way. In this paper, we propose a probabilistic framework to predict short-term PV output taking into account the uncertainty of weather data as well as the variability of PV output over time. To this end, we use datasets comprising of meteorological weather data such as temperature, irradiance, zenith, and azimuth and solar power output. We cluster these data in categories and train a Matern 5/2 Gaussian Process Regression model for each cluster. More specifically, we cluster the data into one to eight different partitions by making use of the k-means algorithm. In order to identify the optimal number of clusters we use the Elbow and Gap methods. We compare the results obtained for the different number of clusters with the (i) 5-fold cross-validation; and (ii) holding out 30 representative days as test data. The results showed that the optimal number of clusters is four, since in comparison to higher number of clusters the increase in the forecast error was marginal.
- Published
- 2021
- Full Text
- View/download PDF
4. Climate change and built environment - the role of urban greenery as a mitigation strategy in Greek urban areas
- Author
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Apostolopoulou, D, primary and Tsoka, S, additional
- Published
- 2021
- Full Text
- View/download PDF
5. Histological validation of a laser fluorescence device for occlusal caries detection in primary molars
- Author
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Apostolopoulou, D., Lagouvardos, P., Kavvadia, K., and Papagiannoulis, L.
- Published
- 2009
- Full Text
- View/download PDF
6. Genetic analysis of syndromic and nonsyndromic patients with craniosynostosis identifies novel mutations in the TWISTI and EfnbI Genes
- Author
-
Apostolopoulou, D. Kaxira, O.S. Hatzaki, A. Panagopoulos, K.P. Alexandrou, K. Stratoudakis, A. Kollia, P. Aleporou, V.
- Abstract
Introduction: Craniosynostosis, the premature fusion of cranial sutures, is usually divided into 2 major categories: syndromic and nonsyndromic. Mutations in the FGFR1, FGFR2, FGFR3, TWIST1, and EFNB1 genes cause the common craniosynostosis syndromes Muenke, Crouzon and Crouzon with acanthosis nigricans, Apert, Pfeiffer, Saethre-Chotzen, and Craniofrontonasal. Overlapping features among craniosynostosis syndromes, phenotypic heterogeneity even within the same syndrome, especially in the case of Muenke syndrome, and inadequate clinical evaluation can lead to misdiagnosis, which molecular testing can help clarify. Objective: The aim of this study is to investigate the underlying genetic cause in 46 patients with syndromic or nonsyndromic craniosynostosis by direct sequencing and/or microdeletion/microduplication analysis of the FGFR1-3, TWIST1, and EFNB1 genes. Results: Genetic analysis identified 3 novel mutations, c.413T>C - p.(Leu138Pro) [p.(L138P)] in TWIST1, the previously reported c.373G>A - p.(Glu125Lys) [p.(E125K)], and c.717dupA - p.(Leu240IlefsTer79) [p.(L240fs)] mutation in EFNB1 gene as well as 6 previously known mutations and a heterozygous TWIST1 gene deletion. The 2 novel mutations within EFNB1 gene arose de novo, but the novel mutation p.(L138P) within TWIST1 gene was inherited from the patient’s father, who was found to be mosaic for the mutation. To our knowledge, this is the first case of mosaicism described for TWIST1 gene. Conclusions: The contribution of molecular genetic analysis to the diagnosis of patients with syndromic craniosynostosis was useful because some were originally misdiagnosed. Conversely, thorough clinical evaluation can guide molecular testing and result in a correct diagnosis. © 2018, American Cleft Palate-Craniofacial Association.
- Published
- 2018
7. Uveal melanoma: GNAQ and GNA11 mutations in a Greek population
- Author
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Psinakis, F. Katseli, A. Koutsandrea, C. Frangia, K. Florentin, L. Apostolopoulou, D. Dimakopoulou, K. Papakonstantinou, D. Georgopoulou, E. Brouzas, D.
- Subjects
eye diseases - Abstract
Background/Aim: Uveal melanoma is the most common primary adult intraocular malignancy. It is known to have a strong metastatic potential, fatal for the vast majority of patients. In recent years, meticulous cytogenetic and molecular profiling has led to precise prognostication, that unfortunately is not matched by advancements in adjuvant therapies. G Protein subunits alpha Q (GNAQ) and alpha 11 (GNA11) are two of the major driver genes that contribute to the development of uveal melanoma. Understanding their prognostic significance can allow tailored management and facilitate their use in the on-going quest of targeted uveal melanoma therapies. Materials and Methods: Formalin-fixed, paraffin-embedded specimens were obtained from 47 patients of Greek origin, with uveal melanoma. GNAQ and GNA11 genes were screened for mutations in exons 4 and 5, by polymerase chain reaction and Sanger sequencing. Results: The overall mutation frequency of GNAQ/GNA11 genes was 42.4%. A novel mutation c.625-626delinsGC was identified in GNA11. No correlation was observed between the mutation status and metastasis occurrence or overall survival time of patients. Conclusion: Mutations in GNAQ and GNA11 genes in this Greek population present frequencies that qualify them as potential targets for customized therapy.
- Published
- 2017
8. Balancing Authority Area Coordination with Limited Exchange of Information
- Author
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Apostolopoulou, D., Sauer, P. W., and Dominguez-Garcia, A. D.
- Subjects
TK - Abstract
In this paper, we propose a coordination scheme between balancing authority (BA) areas in an interconnected power system that decreases the regulation amount needed as well as the associated costs. Our approach aims at mimicking the behavior of the automatic generation control (AGC) system in a scenario where the whole interconnected system is assumed to be operated by a single BA area. To this end, we modify the area control error (ACE), which is fed into the AGC system of each BA area, and determine the AGC allocation based on a distributed algorithm that identifies the least expensive generators, with the mismatch of the total regulation needed being the only information exchanged between BA areas. We demonstrate the proposed ideas with the 3-machine 9-bus Western Electricity Coordinating Council (WECC) system, and compare the performance of our method with other three existing coordination approaches.
- Published
- 2015
9. Combined validity of DIAGNOdentTM and visual examination for in vitro detection of occlusal caries in primary molars
- Author
-
Kavvadia, K. Lagouvardos, P. Apostolopoulou, D.
- Subjects
stomatognathic system - Abstract
The purpose of this in vitro investigation was to compare in primary molars, the validity of DIAGNOdentTM 2095 on occlusal caries diagnosis used either separately or in combination with direct and/or indirect visual examinations, based on histological examination as the reference method. In 24 extracted primary molars, 111 occlusal pits were examined for caries by one trained operator (intraexaminer reliability k>0.80), using the following examination methods: direct visual (DV), indirect visual (IDV), radiographic (XR), and fluorescence (DD) with the DIAGNOdentTM. The extent of caries was then determined histologically. Sensitivity, specificity, accuracy, and the area under the ROC curve (AUC) were calculated for each method separately as well as for the combination of DD with DV and/or IDV. The DD accuracy was found both for lesions into enamel and into dentin to be 0.70 while the accuracy of the DD combination with DV and IDV was found to be 0.89. The DD AUC for lesions into enamel and into dentin, 0.68, were not statistically significant different from the other methods (p>0.5), however the AUC of the combination of DD with DVand IDV, found to be 0.82, was higher than all the other methods, and this was statistically significant for enamel lesions. The validity of DIAGNOdentTM for occlusal caries diagnosis in primary molars was much higher when the DD was used in combination with direct and indirect visual examination, than when used by itself. © 2010 Springer-Verlag London Ltd.
- Published
- 2012
10. FGFR3 related skeletal dysplasias diagnosed prenatally by ultrasonography and molecular analysis: Presentation of 17 cases
- Author
-
Hatzaki, A. Sifakis, S. Apostolopoulou, D. Bouzarelou, D. Konstantinidou, A. Kappou, D. Sideris, A. Tzortzis, E. Athanassiadis, A. Florentin, L. Theodoropoulos, P. Makatsoris, C. Karadimas, C. Velissariou, V.
- Abstract
Fibroblast Growth Factor Receptor 3 (FGFR3) related skeletal dysplasias are caused by mutations in the FGFR3 gene that result in increased activation of the receptors causing alterations in the process of endochondral ossification in all long bones, and include achondroplasia, hypochondroplasia, thanatophoric dysplasia, and SADDAN. Reports of prenatal diagnosis of FGFR3 related skeletal dysplasias are not rare; however, the correlation between 2nd trimester ultrasonographic findings and underlying molecular defect in these cases is relatively poor. There is a need for specific ultrasound (U/S) predictors than can distinguish lethal from non-lethal cases and aid an earlier prenatal diagnosis. Here we present one familial and 16 sporadic cases with FGFR3 related skeletal dysplasia, and we evaluate biometric parameters and U/S findings consistent with the diagnosis of skeletal dysplasia. U/S scan performed even at the 18th week of gestation can indicate a decreased rate of development of the femora (femur length (FL)
- Published
- 2011
11. Histological validation of a laser fluorescence device for occlusal caries detection in primary molars
- Author
-
Apostolopoulou, D. Lagouvardos, P. Kavvadia, K. Papagiannoulis, L.
- Subjects
stomatognathic system - Abstract
AIM: This was to validate in vitro a laser fluorescence device, DIAGNOdent 2095 - DD, on the detection of occlusal caries in primary molars using the histological examination as the gold standard and to compare the laser fluorescence findings to the results of the conventionally used diagnostic methods. STUDY DESIGN AND METHODS: 111 occlusal pits in 24 extracted primary molars were examined for caries by one trained operator (Intra-examiner Reliability K>0.83), using direct visual (DV), indirect visual (IDV), radiographic (XR) and fluorescence (DD) examinations and then the extent of caries was determined histologically. Sensitivity, specificity, accuracy and the area under the ROC curve - AUC were calculated for all methods, using the histological evaluation as the gold standard. STATISTICS: Differences between examination methods were estimated by pair-wise comparison of their respective AUC. RESULTS: DD's sensitivity for enamel and for dentine lesions respectively was 0.90 and 0.36, its specificity 0.36 and 0.91 and its accuracy 0.61 and 0.65. The DD device exhibited better sensitivity than specificity for enamel lesions and better specificity than sensitivity for lesions into dentine. The DD device was found to have the highest sensitivity for lesions into enamel, specificity and accuracy and as well as the largest AUC compared with all other methods. For lesions into dentine however, according to AUC values the DD was not statistically significant different from the other methods. CONCLUSION: Compared with the other methods, the DD had the highest validity for enamel caries while its validity for caries into dentine was not statistical different from the other methods.
- Published
- 2009
12. A novel de Novo mutation within EFNB1 gene in a young girl with craniofrontonasal syndrome
- Author
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Apostolopoulou, D. Stratoudakis, A. Hatzaki, A. Kaxira, O.S. Panagopoulos, K.P. Kollia, P. Aleporou, V. and Apostolopoulou, D. Stratoudakis, A. Hatzaki, A. Kaxira, O.S. Panagopoulos, K.P. Kollia, P. Aleporou, V.
- Abstract
Craniofrontonasal syndrome is mainly characterized by frontonasal dysplasia, telorbitism, a broad nasal root, and frequently a bifid nose and coronal craniosynostosis. Craniofrontonasal syndrome is an X-linked disorder with an unusual pattern of inheritance because heterozygous females are more severely affected than hemizygous males. The craniofrontonasal syndrome-causing gene is EFNB1, localized in the border region of chromosome Xq12 and Xq13.1, encoding for protein ephrin-B1. Here we aim to investigate the underlying genetic defect of a young girl with craniofrontonasal syndrome. The patient underwent surgical correction of her craniofacial deformities. Genetic analysis was carried out by polymerase chain reaction. Products of exon 2 of the EFNB1 gene were sequenced as well as digested with BpmI enzyme. A novel de novo missense mutation 373G>A was identified within the EFNB1 gene, leading to the replacement of glutamic acid at amino acid position 125 with lysine. The replacement of Glu125 with Lys, which lies within the G-H loop, part of the dimerization ligand-receptor interface, is expected to disrupt the interaction between the Eph receptor and ephrin B1 ligand, thus leading to craniofrontonasal syndrome.
- Published
- 2012
13. Closure of ‘effects of various uncertainty sources on automatic generation control systems’
- Author
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Apostolopoulou, D., primary, Chen, Y. C., additional, Zhang, J., additional, Dominguez-Garcia, A. D., additional, and Sauer, P. W., additional
- Published
- 2013
- Full Text
- View/download PDF
14. Effects of various uncertainty sources on automatic generation control systems
- Author
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Apostolopoulou, D., primary, Chen, Y. C., additional, Zhang, J., additional, Dominguez-Garcia, A. D., additional, and Sauer, P. W., additional
- Published
- 2013
- Full Text
- View/download PDF
15. Th-P16:341 Simvastatin reduces the progression of the early stages (Drusen) of age-related macular degeneration: A pilot study
- Author
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Tzotzas, T., primary, Apostolopoulou, D., additional, Memi, E., additional, Efthymiou, H., additional, and Krassas, G.E., additional
- Published
- 2006
- Full Text
- View/download PDF
16. A Qualitative Risk Analysis for the GPRS Technology.
- Author
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Xenakis, C., Apostolopoulou, D., Panou, A., and Stavrakakis, I.
- Published
- 2008
- Full Text
- View/download PDF
17. Combined validity of DIAGNOdent™ and visual examination for in vitro detection of occlusal caries in primary molars.
- Author
-
Kavvadia K, Lagouvardos P, Apostolopoulou D, Kavvadia, Katerina, Lagouvardos, Panagiotis, and Apostolopoulou, Daphne
- Abstract
The purpose of this in vitro investigation was to compare in primary molars, the validity of DIAGNOdent™ 2095 on occlusal caries diagnosis used either separately or in combination with direct and/or indirect visual examinations, based on histological examination as the reference method. In 24 extracted primary molars, 111 occlusal pits were examined for caries by one trained operator (intra-examiner reliability k > 0.80), using the following examination methods: direct visual (DV), indirect visual (IDV), radiographic (XR), and fluorescence (DD) with the DIAGNOdent™. The extent of caries was then determined histologically. Sensitivity, specificity, accuracy, and the area under the ROC curve (AUC) were calculated for each method separately as well as for the combination of DD with DV and/or IDV. The DD accuracy was found both for lesions into enamel and into dentin to be 0.70 while the accuracy of the DD combination with DV and IDV was found to be 0.89. The DD AUC for lesions into enamel and into dentin, 0.68, were not statistically significant different from the other methods (p > 0.5), however the AUC of the combination of DD with DV and IDV, found to be 0.82, was higher than all the other methods, and this was statistically significant for enamel lesions. The validity of DIAGNOdent™ for occlusal caries diagnosis in primary molars was much higher when the DD was used in combination with direct and indirect visual examination, than when used by itself. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
18. Cascade Hydroelectric Power System Model and its Application to an Optimal Dispatch Design
- Author
-
Apostolopoulou, D. and McCulloch, M.
- Abstract
In this paper we propose an optimal dispatch scheme for a cascade hydroelectric power system that maximises the system efficiency, and minimises the spillage effects. Our approach proposes a methodology that has low computational burden and may be implemented for the short-term operation of a cascade hydroelectric power system. To this end, the non- linear relationships that describe the system physical constraints, e.g., power output, are transformed into affine relationships; thus reducing the computational complexity. The transformations are based on the construction of convex envelopes around bilinear functions; piecewise affine functions; and exploitation of optimisation properties. We demonstrate the efficacy of the proposed methodology with the Seven Forks system located in Kenya, and evaluate the performance of our method in terms of water volume and potential energy saved.
19. STTRE: A Spatio-Temporal Transformer with Relative Embeddings for multivariate time series forecasting.
- Author
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Deihim A, Alonso E, and Apostolopoulou D
- Subjects
- Time Factors, Learning, Natural Language Processing
- Abstract
The prevalence of multivariate time series data across several disciplines fosters a demand and, subsequently, significant growth in the research and advancement of multivariate time series analysis. Drawing inspiration from a popular natural language processing model, the Transformer, we propose the Spatio-Temporal Transformer with Relative Embeddings (STTRE) to address multivariate time series forecasting. This work primarily focuses on developing a Transformer-based framework that can fully exploit the spatio-temporal nature of a multivariate time series by incorporating several of the Transformer's key components, but with augmentations that allow them to excel in multivariate time series forecasting. Current Transformer-based models for multivariate time series often neglect the data's spatial component(s) and utilize absolute position embeddings as their only means to detect the data's temporal component(s), which we show is flawed for time series applications. The lack of emphasis on fully exploiting the spatio-temporality of the data can incur subpar results in terms of accuracy. We redesign relative position representations, which we rename to relative embeddings, to unveil a new method for detecting latent spatial, temporal, and spatio-temporal dependencies more effectively than previous Transformer-based models. We couple these relative embeddings with a restructuring of the Transformer's primary sequence learning mechanism, multi-head attention, in a way that allows for full utilization of relative embeddings, thus achieving up to a 24% improvement in accuracy over other state-of-the-art multivariate time series models on a comprehensive selection of publicly available multivariate time series forecasting datasets., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2023
- Full Text
- View/download PDF
20. Reconstruction of a Comprehensive Interactome and Experimental Data Analysis of FRA10AC1 May Provide Insights into Its Biological Role in Health and Disease.
- Author
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Sarafidou T, Galliopoulou E, Apostolopoulou D, Fragkiadakis GA, and Moschonas NK
- Subjects
- Chromosome Fragile Sites, Nuclear Proteins genetics, RNA Splicing genetics, Data Analysis, RNA Precursors genetics, Spliceosomes genetics, Spliceosomes chemistry, Spliceosomes metabolism
- Abstract
FRA10AC1 , the causative gene for the manifestation of the FRA10A fragile site, encodes a well-conserved nuclear protein characterized as a non-core spliceosomal component. Pre-mRNA splicing perturbations have been linked with neurodevelopmental diseases. FRA10AC1 variants have been, recently, causally linked with severe neuropathological and growth retardation phenotypes. To further elucidate the participation of FRA10AC1 in spliceosomal multiprotein complexes and its involvement in neurological phenotypes related to splicing, we exploited protein-protein interaction experimental data and explored network information and information deduced from transcriptomics. We confirmed the direct interaction of FRA10AC1with ESS2, a non-core spliceosomal protein, mapped their interacting domains, and documented their tissue co-localization and physical interaction at the level of intracellular protein stoichiometries. Although FRA10AC1 and SF3B2, a major core spliceosomal protein, were shown to interact under in vitro conditions, the endogenous proteins failed to co-immunoprecipitate. A reconstruction of a comprehensive, strictly binary, protein-protein interaction network of FRA10AC1 revealed dense interconnectivity with many disease-associated spliceosomal components and several non-spliceosomal regulatory proteins. The topological neighborhood of FRA10AC1 depicts an interactome associated with multiple severe monogenic and multifactorial neurodevelopmental diseases mainly referring to spliceosomopathies. Our results suggest that FRA10AC1 involvement in pre-mRNA processing might be strengthened by interconnecting splicing with transcription and mRNA export, and they propose the broader role(s) of FRA10AC1 in cell pathophysiology.
- Published
- 2023
- Full Text
- View/download PDF
21. Genetic Analysis of Syndromic and Nonsyndromic Patients With Craniosynostosis Identifies Novel Mutations in the TWIST1 and EFNB1 Genes.
- Author
-
Apostolopoulou D, Kaxira OS, Hatzaki A, Panagopoulos KP, Alexandrou K, Stratoudakis A, Kollia P, and Aleporou V
- Abstract
Introduction: Craniosynostosis, the premature fusion of cranial sutures, is usually divided into 2 major categories: syndromic and nonsyndromic. Mutations in the FGFR1 , FGFR2 , FGFR3 , TWIST1 , and EFNB1 genes cause the common craniosynostosis syndromes Muenke, Crouzon and Crouzon with acanthosis nigricans, Apert, Pfeiffer, Saethre-Chotzen, and Craniofrontonasal. Overlapping features among craniosynostosis syndromes, phenotypic heterogeneity even within the same syndrome, especially in the case of Muenke syndrome, and inadequate clinical evaluation can lead to misdiagnosis, which molecular testing can help clarify., Objective: The aim of this study is to investigate the underlying genetic cause in 46 patients with syndromic or nonsyndromic craniosynostosis by direct sequencing and/or microdeletion/microduplication analysis of the FGFR1-3 , TWIST1 , and EFNB1 genes., Results: Genetic analysis identified 3 novel mutations, c.413T>C - p.(Leu138Pro) [p.(L138P)] in TWIST1 , the previously reported c.373G>A - p.(Glu125Lys) [p.(E125K)], and c.717dupA - p.(Leu240IlefsTer79) [p.(L240fs)] mutation in EFNB1 gene as well as 6 previously known mutations and a heterozygous TWIST1 gene deletion. The 2 novel mutations within EFNB1 gene arose de novo, but the novel mutation p.(L138P) within TWIST1 gene was inherited from the patient's father, who was found to be mosaic for the mutation. To our knowledge, this is the first case of mosaicism described for TWIST1 gene., Conclusions: The contribution of molecular genetic analysis to the diagnosis of patients with syndromic craniosynostosis was useful because some were originally misdiagnosed. Conversely, thorough clinical evaluation can guide molecular testing and result in a correct diagnosis.
- Published
- 2018
- Full Text
- View/download PDF
22. Uveal Melanoma: GNAQ and GNA11 Mutations in a Greek Population.
- Author
-
Psinakis F, Katseli A, Koutsandrea C, Frangia K, Florentin L, Apostolopoulou D, Dimakopoulou K, Papakonstantinou D, Georgopoulou E, and Brouzas D
- Subjects
- Adult, Aged, Aged, 80 and over, DNA Mutational Analysis, Female, Genetic Predisposition to Disease, Greece, Humans, Kaplan-Meier Estimate, Male, Middle Aged, Mutation Rate, Phenotype, Prognosis, Risk Factors, Time Factors, Uveal Neoplasms mortality, Uveal Neoplasms pathology, Uveal Neoplasms therapy, Biomarkers, Tumor genetics, GTP-Binding Protein alpha Subunits genetics, GTP-Binding Protein alpha Subunits, Gq-G11 genetics, Mutation, Uveal Neoplasms genetics
- Abstract
Background/aim: Uveal melanoma is the most common primary adult intraocular malignancy. It is known to have a strong metastatic potential, fatal for the vast majority of patients. In recent years, meticulous cytogenetic and molecular profiling has led to precise prognostication, that unfortunately is not matched by advancements in adjuvant therapies. G Protein subunits alpha Q (GNAQ) and alpha 11 (GNA11) are two of the major driver genes that contribute to the development of uveal melanoma. Understanding their prognostic significance can allow tailored management and facilitate their use in the on-going quest of targeted uveal melanoma therapies., Materials and Methods: Formalin-fixed, paraffin-embedded specimens were obtained from 47 patients of Greek origin, with uveal melanoma. GNAQ and GNA11 genes were screened for mutations in exons 4 and 5, by polymerase chain reaction and Sanger sequencing., Results: The overall mutation frequency of GNAQ/GNA11 genes was 42.4%. A novel mutation c.625_626delinsGC was identified in GNA11. No correlation was observed between the mutation status and metastasis occurrence or overall survival time of patients., Conclusion: Mutations in GNAQ and GNA11 genes in this Greek population present frequencies that qualify them as potential targets for customized therapy., (Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)
- Published
- 2017
- Full Text
- View/download PDF
23. A novel de novo mutation within EFNB1 gene in a young girl with craniofrontonasal syndrome.
- Author
-
Apostolopoulou D, Stratoudakis A, Hatzaki A, Kaxira OS, Panagopoulos KP, Kollia P, and Aleporou V
- Subjects
- Adolescent, Craniofacial Abnormalities diagnostic imaging, Craniofacial Abnormalities surgery, Exons, Female, Humans, Imaging, Three-Dimensional, Mutation, Sequence Analysis, DNA, Syndrome, Tomography, X-Ray Computed, Craniofacial Abnormalities genetics, Ephrin-B1 genetics
- Abstract
Craniofrontonasal syndrome is mainly characterized by frontonasal dysplasia, telorbitism, a broad nasal root, and frequently a bifid nose and coronal craniosynostosis. Craniofrontonasal syndrome is an X-linked disorder with an unusual pattern of inheritance because heterozygous females are more severely affected than hemizygous males. The craniofrontonasal syndrome-causing gene is EFNB1, localized in the border region of chromosome Xq12 and Xq13.1, encoding for protein ephrin-B1. Here we aim to investigate the underlying genetic defect of a young girl with craniofrontonasal syndrome. The patient underwent surgical correction of her craniofacial deformities. Genetic analysis was carried out by polymerase chain reaction. Products of exon 2 of the EFNB1 gene were sequenced as well as digested with BpmI enzyme. A novel de novo missense mutation 373G>A was identified within the EFNB1 gene, leading to the replacement of glutamic acid at amino acid position 125 with lysine. The replacement of Glu125 with Lys, which lies within the G-H loop, part of the dimerization ligand-receptor interface, is expected to disrupt the interaction between the Eph receptor and ephrin B1 ligand, thus leading to craniofrontonasal syndrome.
- Published
- 2012
- Full Text
- View/download PDF
24. FGFR3 related skeletal dysplasias diagnosed prenatally by ultrasonography and molecular analysis: presentation of 17 cases.
- Author
-
Hatzaki A, Sifakis S, Apostolopoulou D, Bouzarelou D, Konstantinidou A, Kappou D, Sideris A, Tzortzis E, Athanassiadis A, Florentin L, Theodoropoulos P, Makatsoris C, Karadimas C, and Velissariou V
- Subjects
- Female, Humans, Mutation genetics, Pregnancy, Retrospective Studies, Sequence Analysis, DNA, Ultrasonography, Bone Diseases, Developmental diagnostic imaging, Bone Diseases, Developmental genetics, Prenatal Diagnosis methods, Receptor, Fibroblast Growth Factor, Type 3 genetics
- Abstract
Fibroblast Growth Factor Receptor 3 (FGFR3) related skeletal dysplasias are caused by mutations in the FGFR3 gene that result in increased activation of the receptors causing alterations in the process of endochondral ossification in all long bones, and include achondroplasia, hypochondroplasia, thanatophoric dysplasia, and SADDAN. Reports of prenatal diagnosis of FGFR3 related skeletal dysplasias are not rare; however, the correlation between 2nd trimester ultrasonographic findings and underlying molecular defect in these cases is relatively poor. There is a need for specific ultrasound (U/S) predictors than can distinguish lethal from non-lethal cases and aid an earlier prenatal diagnosis. Here we present one familial and 16 sporadic cases with FGFR3 related skeletal dysplasia, and we evaluate biometric parameters and U/S findings consistent with the diagnosis of skeletal dysplasia. U/S scan performed even at the 18th week of gestation can indicate a decreased rate of development of the femora (femur length (FL) <5th centile), while the mean gestational age at diagnosis is still around the 26th week. The utility of other biometric parameters and ratios is discussed (foot length, BPD, HC, FL/foot, and FL/AC). Prenatal cytogenetic and molecular genetic analyses were performed. A final diagnosis was reached by molecular analysis. In two cases of discontinued pregnancy, fetal autopsy led to a phenotypic diagnosis and confirmed the prenatal prediction of lethality. We conclude that the combination of U/S and molecular genetic approach is helpful for establishing an accurate diagnosis of FGFR3-related skeletal dysplasias in utero and subsequently for appropriate genetic counselling and perinatal management., (Copyright © 2011 Wiley-Liss, Inc.)
- Published
- 2011
- Full Text
- View/download PDF
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