72 results on '"Pérez García, V."'
Search Results
2. Experimental energy evaluation of R516A and R513A as replacement of R134a in refrigeration and air conditioning modes
- Author
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Méndez-Méndez, D., Pérez-García, V., and Morales-Fuentes, A.
- Published
- 2023
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3. Mathematical models of leukaemia and its treatment: a review
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Chulián, S., Martínez-Rubio, Á., Rosa, M., and Pérez-García, V. M.
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- 2022
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4. Experimental study of influence of internal heat exchanger in a chest freezer using r-513a as replacement of r-134a
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Pérez-García, V., Méndez-Méndez, D., Belman-Flores, J.M., Rodríguez-Muñoz, J.L., Montes-Rodríguez, J.J., and Ramírez-Minguela, J.J.
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- 2022
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5. Correction to: Mathematical models of leukaemia and its treatment: a review
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Chulián, S., Martínez-Rubio, Á., Rosa, M., and Pérez-García, V. M.
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- 2022
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6. Theoretical modeling and experimental validation of a small capacity diffusion-absorption refrigerator
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Pérez-García, V., Rodríguez-Muñoz, J.L., Belman-Flores, J.M., Rubio-Maya, C., and Ramírez-Minguela, J.J.
- Published
- 2019
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7. Energy and exergy performance of the IHX position in ejector expansion refrigeration systems
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Rodríguez-Muñoz, J.L., Pérez-García, V., Belman-Flores, J.M., Ituna-Yudonago, J.F., and Gallegos-Muñoz, A.
- Published
- 2018
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8. Comparison of the thermo-hydraulic performance and the entropy generation rate for two types of low temperature solar collectors using CFD
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Ramírez-Minguela, J.J., Alfaro-Ayala, J.A., Rangel-Hernández, V.H., Uribe-Ramírez, A.R., Mendoza-Miranda, J.M., Pérez-García, V., and Belman-Flores, J.M.
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- 2018
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9. Exergy assessment of a refrigeration plant using computational intelligence based on hybrid learning methods
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Belman-Flores, J.M., Barroso-Maldonado, J.M., Ledesma, Sergio, Pérez-García, V., Gallegos-Muñoz, A., and Alfaro-Ayala, J.A.
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- 2018
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10. Comparative analysis of energy improvements in single transcritical cycle in refrigeration mode
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Pérez-García, V., Rodríguez-Muñoz, J.L., Ramírez-Minguela, J.J., Belman-Flores, J.M., and Méndez-Díaz, S.
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- 2016
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11. Solid oxide fuel cell numerical study: modified MOLB-type and simple planar geometries with internal reforming
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Ramírez-Minguela, J.J., Rodríguez-Muñoz, J.L., Pérez-García, V., Mendoza-Miranda, J.M., Muñoz-Carpio, V.D., and Alfaro-Ayala, J.A.
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- 2015
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12. Internal reforming of methane in a mono-block-layer build solid oxide fuel cell with an embedding porous pipe: Numerical analysis
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Ramírez-Minguela, J.J., Mendoza-Miranda, J.M., Muñoz-Carpio, V.D., Rangel-Hernández, V.H., Pérez-García, V., and Rodríguez-Muñoz, J.L.
- Published
- 2014
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13. Comparative study of transcritical vapor compression configurations using CO2 as refrigeration mode base on simulation
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Pérez-García, V., Belman-Flores, J.M., Navarro-Esbrí, J., and Rubio-Maya, C.
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- 2013
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14. A new device laboratory: Experimental validation
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Pujol, G., Acho, L., Näpoles, A., Estrada, J., Santos, D., and Pérez-García, V.
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- 2013
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15. Chiralvs. symmetric states in optical isomers
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Pérez-García, V. M., Gonzalo, I., and Pérez-Díaz, J. L.
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- 1993
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16. An overview of refrigeration and its impact on the development in the Democratic Republic of Congo.
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Ituna-Yudonago, Jean Fulbert, Belman-Flores, J. M., and Pérez-García, V.
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REFRIGERATION & refrigerating machinery ,SUSTAINABLE development ,SCIENTISTS ,ECONOMIC indicators - Abstract
The development of refrigeration is a priority in all countries, given the multidimensional roles that it plays in the sustainable development of society. In developing countries, efforts are being made to catch up with the delayed experienced in the use of refrigeration. To achieve this goal, several countries are allowed to trace the history of refrigeration in their countries in order to understand the main causes of non-expansion, and then set up a new strategy of sustainable development for this technology. The Democratic Republic of Congo (DRC) is a developing country that has experienced a very interesting history of refrigeration, but is still less known by the Congolese themselves as well as by scientists. This paper has traced out the outline in the history of refrigeration in the DRC. Surveys were conducted in the industrial, health, residential, commercial, and tourism sectors during the colonial and post-colonial period. Results showed that the use of refrigeration in the DRC has been remarkably observed in the industrial sector, especially in breweries, with a cooling capacity ranging from 50.1 thousand to 2.88 million kWh, about 5 659 % between 1929 and 1957; from 3 million to 26.5 million kWh, about 783.3 % between 1958 and 1980, and then dropped to 6.5 million kWh in 2004 before resuming its growth up to 11 million kWh in 2009. The variations in the use of refrigeration during the above periods significantly influenced the economy, in the sense that the economic and social indicators of the country grew from 0.415 to 0.430 between 1975 and 1985, and then declined to 0.375 in 2000, due to political instability, before rising up to 0.410 in 2005. [ABSTRACT FROM AUTHOR]
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- 2015
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17. Mathematical model predicts response to radiotherapy of grade II gliomas
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Pérez Romasanta, L., Belmonte Beitia, J., Martínez González, A., Fernández Calvo, G., and Pérez García, V.
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- 2013
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18. EP-0995: Response of low grade gliomas to radiotherapy: A mathematical model and its therapeutical implications.
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Perez Romasanta, L., Martinez, A., and Perez Garcia, V.
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- 2013
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19. Chiral vs. symmetric states in optical isomers.
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Pérez-García, V., Gonzalo, I., and Pérez-Díaz, J.
- Abstract
An extension of a recent model explaining the stability of chiral molecules is presented here. From the comparison between the energy reduction produced by the adoption of a chiral form and that produced by a symmetric superposition of chiral states it is concluded that the true fundamental state of the chiral molecules is the chiral one, which eliminates the well-known «optical-isomers paradox». Also, a discussion on the main differences between the approach used here and the previous attempts of explanation based in the double-well model is made. [ABSTRACT FROM AUTHOR]
- Published
- 1993
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20. An Advanced Exergoeconomic Comparison of CO 2 -Based Transcritical Refrigeration Cycles.
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Belman-Flores, J. M., Rangel-Hernández, V. H., Pérez-García, V., Zaleta-Aguilar, A., Fang, Qingping, and Méndez-Méndez, D.
- Subjects
EXERGY ,CARBON dioxide ,REFRIGERATION & refrigerating machinery ,POLLUTION control costs ,PRODUCT costing ,ENVIRONMENTAL economics - Abstract
CO
2 -based transcritical refrigeration cycles are currently gaining significant research attention, as they offer a viable solution to the use of natural refrigerants (e.g., CO2 ). However, there are almost no papers that offer an exergoeconomic comparison between the different configurations of these types of systems. Accordingly, the present work deals with a comparative exergoeconomic analysis of four different CO2 -based transcritical refrigeration cycles. In addition, the work is complemented by an analysis of the CO2 abatement costs. The influences of the variation of the evaporating temperature, the gas cooler outlet temperature, and the pressure ratio on the exergy efficiency, product cost rate, exergy destruction cost rate, exergoeconomic factor, and CO2 penalty cost rate are compared in detail. The results show that the transcritical cycle with the ejector has the lowest exergetic product cost and a low environmental impact. [ABSTRACT FROM AUTHOR]- Published
- 2020
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21. Influence of operational modes of the internal heat exchanger in an experimental installation using R-450A and R-513A as replacement alternatives for R-134a.
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Pérez-García, V., Mota-Babiloni, A., and Navarro-Esbrí, J.
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EXERGY , *HEAT exchangers , *SECOND law of thermodynamics , *WORKING fluids - Abstract
This paper presents a first and second law of thermodynamics study using experimental data from a medium capacity refrigeration system using R-450A, R-513A and R-134a as working fluids and an internal heat exchanger (IHX) operating in three different modes: disabled (Off), activated at 38% thermal effectiveness (Middle), and activated at 78% thermal effectiveness, which is the maximum value by design (ON). When the IHX is in the Middle mode, R-513A showed to be the best option and its coefficient of performance (COP) overcomes that of R-450A and R-134a. On the other hand, for temperatures above of −7.5 °C, both R-450A and R-134a reached the highest COP when the ON and Off modes were set, respectively.Regarding the second law study, for the Off and Middle mode, the largest exergy destruction happens in the compressor for the three refrigerants. The influence of the IHX can be observed directly in the increase of the global exergetic efficiency which passes from being 8.7% in Middle mode to 18.3% for the ON mode. Additionally, a reduction of exergy destruction ratio is seen from the Middle mode, 10.6%–22.2% in the ON mode. Image 1 • The use of an IHX in different activation modes produces an increase in the COP. • The activation of an IHX promotes the highest exergy destruction in condenser. • Use of R-513A is suggested only if an IHX is incorporated in a refrigeration cycle. • Use of an IHX can reduce exergy destruction up to 22.2%. [ABSTRACT FROM AUTHOR]
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- 2019
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22. The agronomic value of the sewage sludge of Tenerife. Physico-chemical characteristics of the refuse-sludge compost and related products
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Pérez García, V., Iglesias Jiménez, E., and Fernández Falcón, M.
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- 1986
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23. The agronomic value of the sewage sludge of Tenerife. Composting
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Iglesias Jiménez, E., Pérez García, V., and Fernández Falcón, M.
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- 1986
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24. Molybdenum tricarbonyl complexes containing unidentate diphosphine. NMR study of fac-mer isomers and crystal structure of fac-Mo(CO) 3(η 2-phen)(η 1-dppm)
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Cano, M., Campo, J.A., Pérez-García, V., Gutiérrez-Puebla, E., and Alvarez-Ibarra, C.
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- 1990
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25. Study of the entropy generation in a SOFC for different operating conditions.
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Ramírez-Minguela, J.J., Uribe-Ramírez, A.R., Mendoza-Miranda, J.M., Pérez-García, V., Rodríguez-Muñoz, J.L., Minchaca-Mojica, J.I., and Alfaro-Ayala, J.A.
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- *
ENTROPY , *SOLID oxide fuel cells , *IRREVERSIBLE processes (Thermodynamics) , *COMPUTATIONAL fluid dynamics , *HEAT transfer , *ELECTROCHEMICAL analysis - Abstract
In the present work, the behavior of a MOLB-type (mono-block layer built) SOFC (solid oxide fuel cells), with different electrolyte thicknesses and operating conditions at the inlet, such as mass fraction, temperature and velocity, is numerically investigated. An entropy generation analysis is carried out in the fuel cell and it is evaluated how the operating conditions and electrolyte thicknesses affect the prediction of the thermodynamic irreversibility. For this investigation a three-dimensional CFD model was developed using the finite volume method derived from a control-volume formulation that takes into account the heat transfer, the transport of species and the electrochemical reactions. Different simulations are performed and the contribution of the local entropy generation rate is computed. The results show different trends for the current density, temperature, species, activation loss, ohmic loss and concentration loss throughout the fuel cell, and indicate that the prediction of thermodynamic irreversibilities is strongly affected by the choice of the operating conditions (e.g. inlet temperature) and the electrolyte thickness. Both local and global entropy generation rates show strong variations. The results of this work are useful in helping the designer to select the different operating conditions of a MOLB-type SOFC with lower irreversibilities. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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26. Altered uterine leptin signalling in obese mothers: from impaired decidualisation to pregnancy complications.
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Walewska E, Hamada Z, Pérez-García V, and Galvão A
- Abstract
Obesity drastically affects maternal health and reproductive outcomes, being often associated with endocrine imbalance, compromised ovarian function, and pregnancy complications. The plastic nature of pregnancy may render the developing fetus particularly vulnerable to oscillations in maternal metabolism, ultimately shaping the health trajectories of the offspring. Presently, we discuss the impact of maternal obesity on decidualisation, a critical step for embryo implantation and placental development. Decidualisation encompasses the differentiation of endometrial stromal cells into specialised decidua. Impaired decidualisation was linked to pregnancy complications, and recent studies suggest that maternal obesity has a detrimental effect on decidualisation. Leptin, an adipokine significantly increased in the circulation of obese women, is known to regulate endometrial function and decidualisation, modulating immune response, angiogenesis, and cell proliferation. Furthermore, hyperleptinaemia in obese mothers was linked to altered leptin signalling in the uterus and compromised endometrial function. In this review, we explore the underlying molecular mechanisms linking altered uterine leptin signalling to impaired decidualisation and early pregnancy complications in obese mothers.
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- 2024
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27. Reduced Levels of miR-145-3p Drive Cell Cycle Progression in Advanced High-Grade Serous Ovarian Cancer.
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González-Cantó E, Monteiro M, Aghababyan C, Ferrero-Micó A, Navarro-Serna S, Mellado-López M, Tomás-Pérez S, Sandoval J, Llueca A, Herreros-Pomares A, Gilabert-Estellés J, Pérez-García V, and Marí-Alexandre J
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- Humans, Female, Cell Line, Tumor, DNA Methylation genetics, Down-Regulation genetics, Neoplasm Grading, Cystadenocarcinoma, Serous genetics, Cystadenocarcinoma, Serous pathology, Cystadenocarcinoma, Serous metabolism, Cyclin-Dependent Kinase 6 metabolism, Cyclin-Dependent Kinase 6 genetics, MicroRNAs genetics, MicroRNAs metabolism, Ovarian Neoplasms genetics, Ovarian Neoplasms pathology, Ovarian Neoplasms metabolism, Gene Expression Regulation, Neoplastic, Cell Movement genetics, Cell Cycle genetics, Cell Proliferation genetics
- Abstract
High-grade serous ovarian cancer (HGSOC) is the most lethal form of gynecologic cancer, with limited treatment options and a poor prognosis. Epigenetic factors, such as microRNAs (miRNAs) and DNA methylation, play pivotal roles in cancer progression, yet their specific contributions to HGSOC remain insufficiently understood. In this study, we performed comprehensive high-throughput analyses to identify dysregulated miRNAs in HGSOC and investigate their epigenetic regulation. Analysis of tissue samples from advanced-stage HGSOC patients revealed 20 differentially expressed miRNAs, 11 of which were corroborated via RT-qPCR in patient samples and cancer cell lines. Among these, miR-145-3p was consistently downregulated post-neoadjuvant therapy and was able to distinguish tumoural from control tissues. Further investigation confirmed that DNA methylation controls MIR145 expression. Functional assays showed that overexpression of miR-145-3p significantly reduced cell migration and induced G0/G1 cell cycle arrest by modulating the cyclin D1-CDK4/6 pathway. These findings suggest that miR-145-3p downregulation enhances cell proliferation and motility in HGSOC, implicating its restoration as a potential therapeutic target focused on G1/S phase regulation in the treatment of HGSOC.
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- 2024
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28. Understanding the intersection between placental development and cancer: Lessons from the tumor suppressor BAP1.
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Doria-Borrell P and Pérez-García V
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- Female, Humans, Pregnancy, Animals, Placenta metabolism, Tumor Suppressor Proteins metabolism, Tumor Suppressor Proteins genetics, Placentation, Neoplasms genetics, Neoplasms metabolism, Neoplasms etiology, Neoplasms pathology, Ubiquitin Thiolesterase metabolism, Ubiquitin Thiolesterase genetics
- Abstract
The placenta, a pivotal organ in mammalian reproduction, allows nutrient exchange and hormonal signaling between the mother and the developing fetus. Understanding its molecular intricacies is essential for deciphering normal embryonic development and pathological conditions such as tumorigenesis. Here, we explore the multifaceted role of the tumor suppressor BRCA1-associated protein 1 (BAP1) in cancer and placentation. Initially recognized for its tumor-suppressive properties, BAP1 has emerged as a key regulator at the intersection of tumorigenesis and placental development. BAP1 influences crucial cellular processes such as cell death, proliferation, metabolism, and response to hypoxic conditions. By integrating insights from tumor and developmental biology, we illuminate the complex molecular pathways orchestrated by BAP1. This perspective highlights BAP1's significant impact on both cancer and placental development, and suggests novel therapeutic strategies that could improve outcomes for pregnancy disorders and cancer., (© 2024. The Author(s).)
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- 2024
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29. The GPI-anchor biosynthesis pathway is critical for syncytiotrophoblast differentiation and placental development.
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Álvarez-Sánchez A, Grinat J, Doria-Borrell P, Mellado-López M, Pedrera-Alcócer É, Malenchini M, Meseguer S, Hemberger M, and Pérez-García V
- Subjects
- Female, Pregnancy, Animals, Humans, Mice, Placenta metabolism, Placenta cytology, Wnt Signaling Pathway, Pre-Eclampsia metabolism, Pre-Eclampsia genetics, Pre-Eclampsia pathology, Endoplasmic Reticulum metabolism, Biosynthetic Pathways genetics, Unfolded Protein Response, CRISPR-Cas Systems, Trophoblasts metabolism, Trophoblasts cytology, Cell Differentiation, Placentation genetics, Glycosylphosphatidylinositols metabolism, Glycosylphosphatidylinositols biosynthesis
- Abstract
The glycosylphosphatidylinositol (GPI) biosynthetic pathway in the endoplasmic reticulum (ER) is crucial for generating GPI-anchored proteins (GPI-APs), which are translocated to the cell surface and play a vital role in cell signaling and adhesion. This study focuses on two integral components of the GPI pathway, the PIGL and PIGF proteins, and their significance in trophoblast biology. We show that GPI pathway mutations impact on placental development impairing the differentiation of the syncytiotrophoblast (SynT), and especially the SynT-II layer, which is essential for the establishment of the definitive nutrient exchange area within the placental labyrinth. CRISPR/Cas9 knockout of Pigl and Pigf in mouse trophoblast stem cells (mTSCs) confirms the role of these GPI enzymes in syncytiotrophoblast differentiation. Mechanistically, impaired GPI-AP generation induces an excessive unfolded protein response (UPR) in the ER in mTSCs growing in stem cell conditions, akin to what is observed in human preeclampsia. Upon differentiation, the impairment of the GPI pathway hinders the induction of WNT signaling for early SynT-II development. Remarkably, the transcriptomic profile of Pigl- and Pigf-deficient cells separates human patient placental samples into preeclampsia and control groups, suggesting an involvement of Pigl and Pigf in establishing a preeclamptic gene signature. Our study unveils the pivotal role of GPI biosynthesis in early placentation and uncovers a new preeclampsia gene expression profile associated with mutations in the GPI biosynthesis pathway, providing novel molecular insights into placental development with implications for enhanced patient stratification and timely interventions., (© 2024. The Author(s).)
- Published
- 2024
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30. CRISPR Activation in Mouse Trophoblast Stem Cells.
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Pérez-García I and Pérez-García V
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- Pregnancy, Female, Animals, Mice, Trophoblasts, Placentation physiology, Cell Differentiation genetics, Stem Cells, Placenta, RNA, Guide, CRISPR-Cas Systems
- Abstract
The placenta is a vital organ that regulates nutrient supply to the developing embryo during gestation. In mice, the placenta is composed of trophoblast lineage and mesodermal derivatives, which merge through the chorioallantoic fusion process in a critical event for the progression of placenta development. The trophoblast lineage is derived from self-renewing, multipotent cells known as mouse trophoblast stem cells (mTSCs). These cells are a valuable tool that allows scientists to comprehend the signals regulating major placental cell types' self-renewal and differentiation capacity. Recent advances in CRISPR-Cas9 genome editing applied in mTSCs have provided novel insights into the molecular networks involved in placentation. Here, we present a comprehensive CRISPR activation (CRISPRa) protocol based on the CRISPR/gRNA-directed synergistic activation mediator (SAM) method to overexpress specific target genes in mTSCs., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)
- Published
- 2024
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31. Generation of Knockout Mouse Trophoblast Stem Cells by CRISPR/Cas9.
- Author
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Doria-Borrell P, Moya-Navamuel M, Hemberger M, and Pérez-García V
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- Pregnancy, Female, Animals, Mice, Mice, Knockout, Trophoblasts, Cell Differentiation genetics, Stem Cells, Mammals, Placenta, CRISPR-Cas Systems
- Abstract
The placenta is the organ that dictates the reproductive outcome of mammalian pregnancy by supplying nutrients and oxygen to the developing fetus to sustain its normal growth. During early mammalian development, trophoblast cells are the earliest cell type to differentiate with multipotent capacity to generate the trophoblast components of the placenta. The isolation and use of mouse trophoblast stem cells (mTSCs) to model in vitro trophoblast differentiation, in combination with CRISPR/Cas9 genome editing technology, has provided tremendous insight into the molecular mechanisms governing early mouse placentation. By knocking out a specific gene of interest in mTSCs, researchers are shedding light onto the molecular pathways involved in normal placental development and pregnancy disorders associated with abnormal placentation. In this chapter, we provide a detailed protocol for the genetic modification of mTSCs by using CRISPR/Cas9 genome editing system., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)
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- 2024
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32. A Thermo-Catalytic Pyrolysis of Polystyrene Waste Review: A Systematic, Statistical, and Bibliometric Approach.
- Author
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Gonzalez-Aguilar AM, Pérez-García V, and Riesco-Ávila JM
- Abstract
Global polystyrene (PS) production has been influenced by the lightness and heat resistance this material offers in different applications, such as construction and packaging. However, population growth and the lack of PS recycling lead to a large waste generation, affecting the environment. Pyrolysis has been recognized as an effective recycling method, converting PS waste into valuable products in the chemical industry. The present work addresses a systematic, bibliometric, and statistical analysis of results carried out from 2015 to 2022, making an extensive critique of the most influential operation parameters in the thermo-catalytic pyrolysis of PS and its waste. The systematic study showed that the conversion of PS into a liquid with high aromatic content (84.75% of styrene) can be achieved by pyrolysis. Discussion of PS as fuel is described compared to commercial fuels. In addition, PS favors the production of liquid fuel when subjected to co-pyrolysis with biomass, improving its properties such as viscosity and energy content. A statistical analysis of the data compilation was also discussed, evaluating the influence of temperature, reactor design, and catalysts on product yield.
- Published
- 2023
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33. Stochastic Fluctuations Drive Non-genetic Evolution of Proliferation in Clonal Cancer Cell Populations.
- Author
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Ortega-Sabater C, F Calvo G, Dinić J, Podolski A, Pesic M, and Pérez-García V
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- Humans, Models, Biological, Ecosystem, Mathematical Concepts, Phenotype, Cell Proliferation, Stochastic Processes, Biological Evolution, Carcinoma, Non-Small-Cell Lung, Lung Neoplasms
- Abstract
Evolutionary dynamics allows us to understand many changes happening in a broad variety of biological systems, ranging from individuals to complete ecosystems. It is also behind a number of remarkable organizational changes that happen during the natural history of cancers. These reflect tumour heterogeneity, which is present at all cellular levels, including the genome, proteome and phenome, shaping its development and interrelation with its environment. An intriguing observation in different cohorts of oncological patients is that tumours exhibit an increased proliferation as the disease progresses, while the timescales involved are apparently too short for the fixation of sufficient driver mutations to promote explosive growth. Here, we discuss how phenotypic plasticity, emerging from a single genotype, may play a key role and provide a ground for a continuous acceleration of the proliferation rate of clonal populations with time. We address this question by combining the analysis of real-time growth of non-small-cell lung carcinoma cells (N-H460) together with stochastic and deterministic mathematical models that capture proliferation trait heterogeneity in clonal populations to elucidate the contribution of phenotypic transitions on tumour growth dynamics., (© 2022. The Author(s), under exclusive licence to Society for Mathematical Biology.)
- Published
- 2022
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34. PI3Kβ-regulated β-catenin mediates EZH2 removal from promoters controlling primed human ESC stemness and primitive streak gene expression.
- Author
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Yadav S, Garrido A, Hernández MC, Oliveros JC, Pérez-García V, Fraga MF, and Carrera AC
- Subjects
- Cell Differentiation genetics, Gene Expression, Humans, JNK Mitogen-Activated Protein Kinases metabolism, Embryonic Stem Cells cytology, Enhancer of Zeste Homolog 2 Protein genetics, Enhancer of Zeste Homolog 2 Protein metabolism, Phosphatidylinositol 3-Kinases metabolism, Primitive Streak, beta Catenin genetics, beta Catenin metabolism
- Abstract
The mechanism governing the transition of human embryonic stem cells (hESCs) toward differentiated cells is only partially understood. To explore this transition, the activity and expression of the ubiquitous phosphatidylinositol 3-kinase (PI3Kα and PI3Kβ) were modulated in primed hESCs. The study reports a pathway that dismantles the restraint imposed by the EZH2 polycomb repressor on an essential stemness gene, NODAL, and on transcription factors required to trigger primitive streak formation. The primitive streak is the site where gastrulation begins to give rise to the three embryonic cell layers from which all human tissues derive. The pathway involves a PI3Kβ non-catalytic action that controls nuclear/active RAC1 levels, activation of JNK (Jun N-terminal kinase) and nuclear β-catenin accumulation. β-Catenin deposition at promoters triggers release of the EZH2 repressor, permitting stemness maintenance (through control of NODAL) and correct differentiation by allowing primitive streak master gene expression. PI3Kβ epigenetic control of EZH2/β-catenin might be modulated to direct stem cell differentiation., Competing Interests: Conflict of interests The authors declare no competing interests., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2022
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35. The imprinted Igf2-Igf2r axis is critical for matching placental microvasculature expansion to fetal growth.
- Author
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Sandovici I, Georgopoulou A, Pérez-García V, Hufnagel A, López-Tello J, Lam BYH, Schiefer SN, Gaudreau C, Santos F, Hoelle K, Yeo GSH, Burling K, Reiterer M, Fowden AL, Burton GJ, Branco CM, Sferruzzi-Perri AN, and Constância M
- Subjects
- Animals, Cell Line, DNA-Binding Proteins genetics, Endothelial Cells metabolism, Female, Fetal Development, Fetus metabolism, Insulin-Like Growth Factor II genetics, Insulin-Like Growth Factor II physiology, Mice, Mice, Inbred C57BL, Microvessels metabolism, Neovascularization, Physiologic physiology, Placenta metabolism, Placenta physiology, Placentation, Pregnancy, Receptor, IGF Type 2 physiology, Transcription Factors genetics, Trophoblasts metabolism, Insulin-Like Growth Factor II metabolism, Placenta blood supply, Receptor, IGF Type 2 metabolism
- Abstract
In all eutherian mammals, growth of the fetus is dependent upon a functional placenta, but whether and how the latter adapts to putative fetal signals is currently unknown. Here, we demonstrate, through fetal, endothelial, hematopoietic, and trophoblast-specific genetic manipulations in the mouse, that endothelial and fetus-derived IGF2 is required for the continuous expansion of the feto-placental microvasculature in late pregnancy. The angiocrine effects of IGF2 on placental microvasculature expansion are mediated, in part, through IGF2R and angiopoietin-Tie2/TEK signaling. Additionally, IGF2 exerts IGF2R-ERK1/2-dependent pro-proliferative and angiogenic effects on primary feto-placental endothelial cells ex vivo. Endothelial and fetus-derived IGF2 also plays an important role in trophoblast morphogenesis, acting through Gcm1 and Synb. Thus, our study reveals a direct role for the imprinted Igf2-Igf2r axis on matching placental development to fetal growth and establishes the principle that hormone-like signals from the fetus play important roles in controlling placental microvasculature and trophoblast morphogenesis., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2022
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36. Letter to the editor regarding "The impact of COVID-19 on neurosurgical head trauma referrals and admission at a tertiary neurosurgical centre".
- Author
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Pérez-García V, Amaris-Pérez A, Escobar-Pacheco C, Ramos-Díaz A, and Lozada-Martínez ID
- Subjects
- Hospitalization, Humans, Referral and Consultation, SARS-CoV-2, COVID-19, Craniocerebral Trauma surgery
- Abstract
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.
- Published
- 2021
- Full Text
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37. Mapping the expression of transient receptor potential channels across murine placental development.
- Author
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De Clercq K, Pérez-García V, Van Bree R, Pollastro F, Peeraer K, Voets T, and Vriens J
- Subjects
- Animals, Calcium Channels genetics, Calcium Channels metabolism, Calcium Signaling, Cell Differentiation, Cell Proliferation, Female, Gene Expression Regulation, Mice, Mice, Inbred C57BL, Mouse Embryonic Stem Cells cytology, Mouse Embryonic Stem Cells metabolism, Pregnancy, Stem Cells cytology, Stem Cells metabolism, TRPV Cation Channels genetics, TRPV Cation Channels metabolism, Transient Receptor Potential Channels genetics, Trophoblasts cytology, Trophoblasts metabolism, Placenta metabolism, Placentation genetics, Transient Receptor Potential Channels metabolism
- Abstract
Transient receptor potential (TRP) channels play prominent roles in ion homeostasis by their ability to control cation influx. Mouse placentation is governed by the processes of trophoblast proliferation, invasion, differentiation, and fusion, all of which require calcium signaling. Although certain TRP channels have been shown to contribute to maternal-fetal transport of magnesium and calcium, a role for TRP channels in specific trophoblast functions has been disregarded. Using qRT-PCR and in situ hybridisation, the spatio-temporal expression pattern of TRP channels in the mouse placenta across gestation (E10.5-E18.5) was assessed. Prominent expression was observed for Trpv2, Trpm6, and Trpm7. Calcium microfluorimetry in primary trophoblast cells isolated at E14.5 of gestation further revealed the functional activity of TRPV2 and TRPM7. Finally, comparing TRP channels expression in mouse trophoblast stem cells (mTSCs) and mouse embryonic stem cells (mESC) confirmed the specific expression of TRPV2 during placental development. Moreover, TRP channel expression was similar in mTSCs compared to primary trophoblasts and validate mTSC as a model to study TRP channels in placental development. Collectivity, our results identify a specific spatio-temporal TRP channel expression pattern in trophoblasts, suggesting a possible involvement in regulating the process of placentation.
- Published
- 2021
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- View/download PDF
38. Caffeine increases whole-body fat oxidation during 1 h of cycling at Fatmax.
- Author
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Ruiz-Moreno C, Gutiérrez-Hellín J, Amaro-Gahete FJ, González-García J, Giráldez-Costas V, Pérez-García V, and Del Coso J
- Subjects
- Adipose Tissue metabolism, Calorimetry, Indirect, Double-Blind Method, Humans, Oxidation-Reduction, Oxygen Consumption, Caffeine, Energy Metabolism
- Abstract
Purpose: The ergogenic effect of caffeine on exercise of maximum intensity has been well established. However, there is controversy regarding the effect of caffeine on shifting substrate oxidation at submaximal exercise. The aim of this study was to investigate the effect of acute caffeine ingestion on whole-body substrate oxidation during 1 h of cycling at the intensity that elicits maximal fat oxidation (Fatmax)., Methods: In a double-blind, randomized, and counterbalanced experiment, 12 healthy participants (VO
2max = 50.7 ± 12.1 mL/kg/min) performed two acute experimental trials after ingesting either caffeine (3 mg/kg) or a placebo (cellulose). The trials consisted of 1 h of continuous cycling at Fatmax. Energy expenditure, fat oxidation rate, and carbohydrate oxidation rate were continuously measured by indirect calorimetry., Results: In comparison to the placebo, caffeine increased the amount of fat oxidized during the trial (19.4 ± 7.7 vs 24.7 ± 9.6 g, respectively; P = 0.04) and decreased the amount of carbohydrate oxidized (94.6 ± 30.9 vs 73.8 ± 32.4 g; P = 0.01) and the mean self-perception of fatigue (Borg scale = 11 ± 2 vs 10 ± 2 arbitrary units; P = 0.05). In contrast, caffeine did not modify total energy expenditure (placebo = 543 ± 175; caffeine = 559 ± 170 kcal; P = 0.60) or mean heart rate (125 ± 13 and 127 ± 9 beats/min; P = 0.30) during exercise. Before exercise, caffeine increased systolic and diastolic blood pressure whilst it increased the feelings of nervousness and vigour after exercise (P < 0.05)., Conclusion: These results suggest that a moderate dose of caffeine (3 mg/kg) increases the amount of fat oxidized during 1 h of cycling at Fatmax. Thus, caffeine might be used as an effective strategy to enhance body fat utilization during submaximal exercise. The occurrence of several side effects should be taken into account when using caffeine to reduce body fat in populations with hypertension or high sensitivity to caffeine.- Published
- 2021
- Full Text
- View/download PDF
39. Global heterogeneity assessed with 18 F-FDG PET/CT. Relation with biological variables and prognosis in locally advanced breast cancer.
- Author
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Tello Galán MJ, García Vicente AM, Pérez Beteta J, Amo Salas M, Jiménez Londoño GA, Pena Pardo FJ, Soriano Castrejón ÁM, and Pérez García VM
- Subjects
- Breast Neoplasms pathology, Female, Humans, Immunohistochemistry, Neoplasm Staging, Predictive Value of Tests, Prognosis, Breast Neoplasms diagnostic imaging, Fluorodeoxyglucose F18, Positron Emission Tomography Computed Tomography methods, Radiopharmaceuticals
- Abstract
Aim: To analyze the relationship between measurements of global heterogeneity, obtained from
18 F-FDG PET/CT, with biological variables, and their predictive and prognostic role in patients with locally advanced breast cancer (LABC)., Material and Methods: 68 patients from a multicenter and prospective study, with LABC and a baseline18 F-FDG PET/CT were included. Immunohistochemical profile [estrogen receptors (ER) and progesterone receptors (PR), expression of the HER-2 oncogene, Ki-67 proliferation index and tumor histological grade], response to neoadjuvant chemotherapy (NC), overall survival (OS) and disease-free survival (DFS) were obtained as clinical variables. Three-dimensional segmentation of the lesions, providing SUV, volumetric [metabolic tumor volume (MTV) and total lesion glycolysis (TLG)] and global heterogeneity variables [coefficient of variation (COV) and SUVmean/SUVmax ratio], as well as sphericity was performed. The correlation between the results obtained with the immunohistochemical profile, the response to NC and survival was also analyzed., Results: Of the patients included, 62 received NC. Only 18 responded. 13 patients relapsed and 11 died during follow-up. ER negative tumors had a lower COV (p=0.018) as well as those with high Ki-67 (p=0.001) and high risk phenotype (p=0.033) compared to the rest. No PET variable showed association with the response to NC nor OS. There was an inverse relationship between sphericity with DFS (p=0.041), so, for every tenth that sphericity increases, the risk of recurrence decreases by 37%., Conclusions: Breast tumors in our LABC dataset behaved as homogeneous and spherical lesions. Larger volumes were associated with a lower sphericity. Global heterogeneity variables and sphericity do not seem to have a predictive role in response to NC nor in OS. More spherical tumors with less variation in gray intensity between voxels showed a lower risk of recurrence., (Copyright © 2019 Sociedad Española de Medicina Nuclear e Imagen Molecular. Publicado por Elsevier España, S.L.U. All rights reserved.)- Published
- 2019
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40. Fetal and trophoblast PI3K p110α have distinct roles in regulating resource supply to the growing fetus in mice.
- Author
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López-Tello J, Pérez-García V, Khaira J, Kusinski LC, Cooper WN, Andreani A, Grant I, Fernández de Liger E, Lam BY, Hemberger M, Sandovici I, Constancia M, and Sferruzzi-Perri AN
- Subjects
- Animals, Female, Fetus, Mice, Pregnancy, Signal Transduction, Class I Phosphatidylinositol 3-Kinases metabolism, Embryonic Stem Cells enzymology, Energy Metabolism, Fetal Development, Placentation, Trophoblasts enzymology
- Abstract
Studies suggest that placental nutrient supply adapts according to fetal demands. However, signaling events underlying placental adaptations remain unknown. Here we demonstrate that phosphoinositide 3-kinase p110α in the fetus and the trophoblast interplay to regulate placental nutrient supply and fetal growth. Complete loss of fetal p110α caused embryonic death, whilst heterozygous loss resulted in fetal growth restriction and impaired placental formation and nutrient transport. Loss of trophoblast p110α resulted in viable fetuses, abnormal placental development and a failure of the placenta to transport sufficient nutrients to match fetal demands for growth. Using RNA-seq we identified genes downstream of p110α in the trophoblast that are important in adapting placental phenotype. Using CRISPR/Cas9 we showed loss of p110α differentially affects gene expression in trophoblast and embryonic stem cells. Our findings reveal important, but distinct roles for p110α in the different compartments of the conceptus, which control fetal resource acquisition and growth., Competing Interests: JL, VP, JK, LK, WC, AA, IG, EF, BL, MH, IS, MC, AS No competing interests declared, (© 2019, López-Tello et al.)
- Published
- 2019
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41. Morphologic Features on MR Imaging Classify Multifocal Glioblastomas in Different Prognostic Groups.
- Author
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Pérez-Beteta J, Molina-García D, Villena M, Rodríguez MJ, Velásquez C, Martino J, Meléndez-Asensio B, Rodríguez de Lope Á, Morcillo R, Sepúlveda JM, Hernández-Laín A, Ramos A, Barcia JA, Lara PC, Albillo D, Revert A, Arana E, and Pérez-García VM
- Subjects
- Adult, Aged, Brain Neoplasms diagnostic imaging, Female, Glioblastoma diagnostic imaging, Humans, Magnetic Resonance Imaging methods, Male, Middle Aged, Prognosis, Proportional Hazards Models, Retrospective Studies, Survival Analysis, Brain Neoplasms classification, Brain Neoplasms pathology, Glioblastoma classification, Glioblastoma pathology
- Abstract
Background and Purpose: Multifocal glioblastomas (ie, glioblastomas with multiple foci, unconnected in postcontrast pretreatment T1-weighted images) represent a challenge in clinical practice due to their poor prognosis. We wished to obtain imaging biomarkers with prognostic value that have not been found previously., Materials and Methods: A retrospective review of 1155 patients with glioblastomas from 10 local institutions during 2006-2017 provided 97 patients satisfying the inclusion criteria of the study and classified as having multifocal glioblastomas. Tumors were segmented and morphologic features were computed using different methodologies: 1) measured on the largest focus, 2) aggregating the different foci as a whole, and 3) recording the extreme value obtained for each focus. Kaplan-Meier, Cox proportional hazards, correlations, and Harrell concordance indices (c-indices) were used for the statistical analysis., Results: Age ( P < .001, hazard ratio = 2.11, c-index = 0.705), surgery ( P < .001, hazard ratio = 2.04, c-index = 0.712), contrast-enhancing rim width ( P < .001, hazard ratio = 2.15, c-index = 0.704), and surface regularity ( P = .021, hazard ratio = 1.66, c-index = 0.639) measured on the largest focus were significant independent predictors of survival. Maximum contrast-enhancing rim width ( P = .002, hazard ratio = 2.05, c-index = 0.668) and minimal surface regularity ( P = .036, hazard ratio = 1.64, c-index = 0.600) were also significant. A multivariate model using age, surgery, and contrast-enhancing rim width measured on the largest foci classified multifocal glioblastomas into groups with different outcomes ( P < .001, hazard ratio = 3.00, c-index = 0.853, median survival difference = 10.55 months). Moreover, quartiles with the highest and lowest individual prognostic scores based on the focus with the largest volume and surgery were identified as extreme groups in terms of survival ( P < .001, hazard ratio = 18.67, c-index = 0.967)., Conclusions: A prognostic model incorporating imaging findings on pretreatment postcontrast T1-weighted MRI classified patients with glioblastoma into different prognostic groups., (© 2019 by American Journal of Neuroradiology.)
- Published
- 2019
- Full Text
- View/download PDF
42. A three-dimensional computational analysis of magnetic resonance images characterizes the biological aggressiveness in malignant brain tumours.
- Author
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Pérez-Beteta J, Martínez-González A, and Pérez-García VM
- Subjects
- Adult, Aged, Aged, 80 and over, Female, Humans, Male, Middle Aged, Brain Neoplasms diagnostic imaging, Glioblastoma diagnostic imaging, Imaging, Three-Dimensional, Magnetic Resonance Imaging
- Abstract
Glioblastoma (GBM) is the most frequent and aggressive type of primary brain tumour. The development of image-based biomarkers from magnetic resonance images (MRIs) has been a topic of recent interest. GBMs on pre-treatment post-contrast T1-weighted (w) MRIs often appear as rim-shaped regions. In this research, we wanted to define rim-shape complexity (RSC) descriptors and study their value as indicators of the tumour's biological aggressiveness. We constructed a set of widths characterizing the rim-shaped contrast-enhancing areas in T1w MRIs, defined measures of the RSC and computed them for 311 GBM patients. Survival analysis, correlations and sensitivity studies were performed to assess the prognostic value of the measurements. All measures obtained from the histograms were found to depend on the class width to some extent. Several measures (FWHM and β
R ) had high prognostic value. Some histogram-independent measures were predictors of survival: maximum rim width, mean rim width and spherically averaged rim width. The later quantity allowed patients to be classified into subgroups with different rates of survival (mean difference 6.28 months, p = 0.006). In conclusion, some of the morphological quantifiers obtained from pre-treatment T1w MRIs provided information on the biological aggressiveness of GBMs. The results can be used to define prognostic measurements of clinical applicability.- Published
- 2018
- Full Text
- View/download PDF
43. Labile haemoglobin as a glycaemic biomarker for patient-specific monitoring of diabetes: mathematical modelling approach.
- Author
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León-Triana O, Calvo GF, Belmonte-Beitia J, Rosa Durán M, Escribano-Serrano J, Michan-Doña A, and Pérez-García VM
- Subjects
- Biomarkers blood, Diabetes Mellitus, Type 2 pathology, Erythrocytes pathology, Humans, Kinetics, Monitoring, Physiologic, Blood Glucose metabolism, Diabetes Mellitus, Type 2 blood, Erythrocytes metabolism, Glycated Hemoglobin metabolism, Models, Biological
- Abstract
Diabetes mellitus constitutes a major health problem and its clinical presentation and progression may vary considerably. A number of standardized diagnostic and monitoring tests are currently used for diabetes. They are based on measuring either plasma glucose, glycated haemoglobin or both. Their main goal is to assess the average blood glucose concentration. There are several sources of interference that can lead to discordances between measured plasma glucose and glycated haemoglobin levels. These include haemoglobinopathies, conditions associated with increased red blood cell turnover or the administration of some therapies, to name a few. Therefore, there is a need to provide new diagnostic tools for diabetes that employ clinically accessible biomarkers which, at the same time, can offer additional information allowing us to detect possible conflicting cases and to yield more reliable evaluations of the average blood glucose level concentration. We put forward a biomathematical model to describe the kinetics of two patient-specific glycaemic biomarkers to track the emergence and evolution of diabetes: glycated haemoglobin and its labile fraction. Our method incorporates erythrocyte age distribution and utilizes a large cohort of clinical data from blood tests to support its usefulness for diabetes monitoring., (© 2018 The Author(s).)
- Published
- 2018
- Full Text
- View/download PDF
44. Efficient fluoride removal using Al-Cu oxide nanoparticles supported on steel slag industrial waste solid.
- Author
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Blanco-Flores A, Arteaga-Larios N, Pérez-García V, Martínez-Gutiérrez J, Ojeda-Escamilla M, and Rodríguez-Torres I
- Subjects
- Adsorption, Kinetics, Particle Size, Surface Properties, Water Purification methods, Aluminum, Copper, Fluorides analysis, Industrial Waste analysis, Nanocomposites chemistry, Oxides, Solid Waste analysis, Steel chemistry, Water Pollutants, Chemical analysis
- Abstract
A SSW/Al-Cu formed from an industrial solid waste and Al-Cu Nps are utilized for the removal of fluoride from aqueous solutions. The SSW/Al-Cu was obtained by a chemical reduction method. The SSW/Al-Cu was characterized by TEM, SEM, FT-IR, XRD, BET, and pH
zpc techniques. The Nps were formed as bimetallic oxides and deposited in the form of spheroidal particles forming agglomerations. The sizes of these particles range from 1 to 3 nm. The surface area and average pore width of SSW/Al-Cu were 2.99 m2 /g and 17.09 nm, respectively. The adsorption kinetics were better described using the second-order model, pointing to chemical adsorption with an equilibrium time of 540 min. The thermodynamic parameters obtained here confirm the spontaneous and endothermic nature of the process. The percentage of fluoride removal was 89.5% using the four-bladed disk turbine, and computational fluid dynamics (CFD) modeling demonstrated that using the four-bladed disk turbine helped improve the fluoride removal process. The maximum adsorption capacity was 3.99 mg/g. The Langmuir-Freundlich model best describes the adsorption process, which occurred by a combination of mechanisms, such as electrostatic interactions between the ions involved in the process. This study proves that the chemical modification of this waste solid created an efficient bimetallic nanomaterial for fluoride removal. Furthermore, the method of preparation of these nanocomposites is quite scalable.- Published
- 2018
- Full Text
- View/download PDF
45. A mathematical model of low grade gliomas treated with temozolomide and its therapeutical implications.
- Author
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Bogdańska MU, Bodnar M, Belmonte-Beitia J, Murek M, Schucht P, Beck J, and Pérez-García VM
- Subjects
- Brain Neoplasms diagnosis, Brain Neoplasms radiotherapy, Cell Proliferation drug effects, Dacarbazine pharmacology, Dacarbazine therapeutic use, Disease Progression, Female, Glioma diagnosis, Glioma radiotherapy, Humans, Male, Middle Aged, Neoplasm Grading, Temozolomide, Brain Neoplasms drug therapy, Brain Neoplasms pathology, Dacarbazine analogs & derivatives, Glioma drug therapy, Glioma pathology, Models, Biological
- Abstract
Low grade gliomas (LGGs) are infiltrative and incurable primary brain tumours with typically slow evolution. These tumours usually occur in young and otherwise healthy patients, bringing controversies in treatment planning since aggressive treatment may lead to undesirable side effects. Thus, for management decisions it would be valuable to obtain early estimates of LGG growth potential. Here we propose a simple mathematical model of LGG growth and its response to chemotherapy which allows the growth of LGGs to be described in real patients. The model predicts, and our clinical data confirms, that the speed of response to chemotherapy is related to tumour aggressiveness. Moreover, we provide a formula for the time to radiological progression, which can be possibly used as a measure of tumour aggressiveness. Finally, we suggest that the response to a few chemotherapy cycles upon diagnosis might be used to predict tumour growth and to guide therapeutical actions on the basis of the findings., (Copyright © 2017 Elsevier Inc. All rights reserved.)
- Published
- 2017
- Full Text
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46. Extraction and analysis of signatures from the Gene Expression Omnibus by the crowd.
- Author
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Wang Z, Monteiro CD, Jagodnik KM, Fernandez NF, Gundersen GW, Rouillard AD, Jenkins SL, Feldmann AS, Hu KS, McDermott MG, Duan Q, Clark NR, Jones MR, Kou Y, Goff T, Woodland H, Amaral FMR, Szeto GL, Fuchs O, Schüssler-Fiorenza Rose SM, Sharma S, Schwartz U, Bausela XB, Szymkiewicz M, Maroulis V, Salykin A, Barra CM, Kruth CD, Bongio NJ, Mathur V, Todoric RD, Rubin UE, Malatras A, Fulp CT, Galindo JA, Motiejunaite R, Jüschke C, Dishuck PC, Lahl K, Jafari M, Aibar S, Zaravinos A, Steenhuizen LH, Allison LR, Gamallo P, de Andres Segura F, Dae Devlin T, Pérez-García V, and Ma'ayan A
- Abstract
Gene expression data are accumulating exponentially in public repositories. Reanalysis and integration of themed collections from these studies may provide new insights, but requires further human curation. Here we report a crowdsourcing project to annotate and reanalyse a large number of gene expression profiles from Gene Expression Omnibus (GEO). Through a massive open online course on Coursera, over 70 participants from over 25 countries identify and annotate 2,460 single-gene perturbation signatures, 839 disease versus normal signatures, and 906 drug perturbation signatures. All these signatures are unique and are manually validated for quality. Global analysis of these signatures confirms known associations and identifies novel associations between genes, diseases and drugs. The manually curated signatures are used as a training set to develop classifiers for extracting similar signatures from the entire GEO repository. We develop a web portal to serve these signatures for query, download and visualization.
- Published
- 2016
- Full Text
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47. Response to the Letter by Canbaz et al.
- Author
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Abizanda P, Diez-López M, Pérez-García V, de Dios Estrella J, da Silva-González Á, Barcons-Vilardell N, and Araujo-Torres K
- Subjects
- Female, Humans, Male, Dietary Supplements, Exercise, Frail Elderly statistics & numerical data, Nursing Homes, Nutritional Status, Quality of Life, Vitamins administration & dosage
- Published
- 2015
- Full Text
- View/download PDF
48. Phosphoinositide 3-kinase beta protects nuclear envelope integrity by controlling RCC1 localization and Ran activity.
- Author
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Redondo-Muñoz J, Pérez-García V, Rodríguez MJ, Valpuesta JM, and Carrera AC
- Subjects
- Animals, Cell Cycle, Chromatin metabolism, Class I Phosphatidylinositol 3-Kinases, Fibroblasts metabolism, HEK293 Cells, Humans, Lipid Bilayers, Mice, Microscopy, Confocal, Microscopy, Electron, NIH 3T3 Cells, Protein Binding, Cell Cycle Proteins metabolism, Guanine Nucleotide Exchange Factors metabolism, Nuclear Envelope metabolism, Nuclear Proteins metabolism, Phosphatidylinositol 3-Kinases metabolism, ran GTP-Binding Protein metabolism
- Abstract
The nuclear envelope (NE) forms a barrier between the nucleus and the cytosol that preserves genomic integrity. The nuclear lamina and nuclear pore complexes (NPCs) are NE components that regulate nuclear events through interaction with other proteins and DNA. Defects in the nuclear lamina are associated with the development of laminopathies. As cells depleted of phosphoinositide 3-kinase beta (PI3Kβ) showed an aberrant nuclear morphology, we studied the contribution of PI3Kβ to maintenance of NE integrity. pik3cb depletion reduced the nuclear membrane tension, triggered formation of areas of lipid bilayer/lamina discontinuity, and impaired NPC assembly. We show that one mechanism for PI3Kβ regulation of NE/NPC integrity is its association with RCC1 (regulator of chromosome condensation 1), the activator of nuclear Ran GTPase. PI3Kβ controls RCC1 binding to chromatin and, in turn, Ran activation. These findings suggest that PI3Kβ regulates the nuclear envelope through upstream regulation of RCC1 and Ran., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)
- Published
- 2015
- Full Text
- View/download PDF
49. Cell activation-induced phosphoinositide 3-kinase alpha/beta dimerization regulates PTEN activity.
- Author
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Pérez-García V, Redondo-Muñoz J, Kumar A, and Carrera AC
- Subjects
- Animals, Cell Cycle, Cell Line, Class Ia Phosphatidylinositol 3-Kinase genetics, Dimerization, Gene Expression Regulation, HEK293 Cells, Humans, Mice, NIH 3T3 Cells, PTEN Phosphohydrolase genetics, Signal Transduction physiology, Class Ia Phosphatidylinositol 3-Kinase metabolism, PTEN Phosphohydrolase metabolism, Phosphatidylinositol Phosphates metabolism
- Abstract
The phosphoinositide 3-kinase (PI3K)/PTEN (phosphatase and tensin homolog) pathway is one of the central routes that enhances cell survival, division, and migration, and it is frequently deregulated in cancer. PI3K catalyzes formation of phosphatidylinositol 3,4,5-triphosphate [PI(3,4,5)P3] after cell activation; PTEN subsequently reduces these lipids to basal levels. Activation of the ubiquitous p110α isoform precedes that of p110β at several points during the cell cycle. We studied the potential connections between p110α and p110β activation, and we show that cell stimulation promotes p110α and p110β association, demonstrating oligomerization of PI3K catalytic subunits within cells. Cell stimulation also promoted PTEN incorporation into this complex, which was necessary for PTEN activation. Our results show that PI3Ks dimerize in vivo and that PI3K and PTEN activities modulate each other in a complex that controls cell PI(3,4,5)P3 levels., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)
- Published
- 2014
- Full Text
- View/download PDF
50. Phosphoinositide 3-kinase p85beta regulates invadopodium formation.
- Author
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Cariaga-Martínez AE, Cortés I, García E, Pérez-García V, Pajares MJ, Idoate MA, Redondo-Muñóz J, Antón IM, and Carrera AC
- Abstract
The acquisition of invasiveness is characteristic of tumor progression. Numerous genetic changes are associated with metastasis, but the mechanism by which a cell becomes invasive remains unclear. Expression of p85β, a regulatory subunit of phosphoinositide-3-kinase, markedly increases in advanced carcinoma, but its mode of action is unknown. We postulated that p85β might facilitate cell invasion. We show that p85β localized at cell adhesions in complex with focal adhesion kinase and enhanced stability and maturation of cell adhesions. In addition, p85β induced development at cell adhesions of an F-actin core that extended several microns into the cell z-axis resembling the skeleton of invadopodia. p85β lead to F-actin polymerization at cell adhesions by recruiting active Cdc42/Rac at these structures. In accordance with p85β function in invadopodium-like formation, p85β levels increased in metastatic melanoma and p85β depletion reduced invadopodium formation and invasion. These results show that p85β enhances invasion by inducing cell adhesion development into invadopodia-like structures explaining the metastatic potential of tumors with increased p85β levels., (© 2014. Published by The Company of Biologists Ltd.)
- Published
- 2014
- Full Text
- View/download PDF
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