Stromal and tumor cell responses to hypoxia and treatment within the glioma microenvironment

Glioblastoma is the most aggressive primary brain tumor in adults. Despite treatment, tumors invariably recur, and the recurring tumor is resistant to therapies. New approaches are needed for the successful treatment of glioblastoma patients.Tumors are not simply a compilation of molecularly and phenotypically identical neoplastic cells. Instead, the tumor-associated stroma is instrumental in supporting tumor growth. Moreover, the cancer cells themselves are highly plastic, with some of the cells exhibiting stem-like phenotypes. Cancer stemness is linked to more aggressive disease, recurrence, and worse patient outcomes in several cancers. Hypoxic signaling, mediated by the HIF transcription factors, is a cornerstone in the maintenance of cancer stemness in glioblastoma and other cancers.The aim of this thesis was to evaluate how microenvironmental cues affect the interactions between the tumor microenvironment and glioma stem-like cells in glioblastoma. We addressed how treatments and hypoxia affect tumor-associated astrocytes in ways that consequently alter glioma cell properties, and how hypoxia and pseudo-hypoxia are involved in stemness maintenance in glioblastoma. For this work, we used genetically engineered mouse models of glioma, primary stromal and glioma cell lines, classical glioblastoma cell lines, and organotypic slice cultures. We evaluated cell stemness by using multiple functional assays in combination with stem cell marker expression analysis. In papers I and II, we investigated the response of astrocytes to extrinsic factors of the microenvironment, namely radiation and temozolomide treatment, and to intrinsic factors of the microenvironment, namely intermediate and severe hypoxia. Astrocytes became reactive in response to these cues and produced extracellular matrix that altered glioma cell properties, including stemness. In papers III and IV, we investigated the role of hypoxia and pseudo-hypoxia in the maintenance of aggressive glioma phenotypes. We showed that the generation of the cleaved form of the cell surface glycoprotein CD44 leads to the stabilization of the HIFs in the perivascular and the perinecrotic glioma niche, leading to increased hypoxic signaling and glioma cell stemness. Moreover, we showed that p75NTR signaling is involved in the activation of the hypoxic signaling pathway and is also regulating glioma cell stemness and migration in hypoxia.All in all, this thesis elucidated aspects of the glioblastoma microenvironment, namely irradiated and hypoxic astrocytes, and the CD44 and p75NTR signaling, that can lead to the development of new targeted therapeutic strategies

Acute Sclerokeratitis After Cataract Surgery: Treatment with Topical Use of Cyclosporine – A

We would like to report an interesting case of acute sclerokeratitis following cataract surgery treated with topical use of Cyclosporine-A. A 61-year old woman with a past history of scleritis in her right eye had an uneventful phaco surgery in her right eye for cataract removal via a corneoscleral incision. Eight months after the initial surgery the patient had a sudden decrease in her visual acquity in the right eye with marked inflammatory signs in the sclera and cornea adjacent to the entry-site of the phaco surgery. Initially the patient was treated with systemic corticosteroids but due to serious side effects topical cyclosporine-A was added instead. Five months later the patient has a significant improvement in terms of visual acquity with marked reduction in the inflammatory signs both in sclera and corneal tissue. We think that topical Cyclosporine-A with its potent immunomodulating effects seems to be of benefit in those cases where systemic corticosteroids are contraindicated or have serious side-effects

DETECTION OF POST-TRAUMATIC STRESS DISORDER (PTSD) SYMPTOMS ASSOCIATED WITH CORONAVIRUS DISEASE 2019 (COVID-19) IN THE STUDENT POPULATION

The pandemic has killed at least 670,000 people since it hit China's Wuhan, and 17 million cases have been diagnosed. The United States, Brazil, Mexico and Britain have been hit hard by COVID-19 in recent weeks (7/2020) as their governments try to find an effective response. A pandemic is a health crisis that occurs once in a hundred years, the effects of which will be felt for decades (WHO). In the dramatic changes brought about by a crisis, unfortunately many people experience a time of stress and sadness like no other in their lives and then the most common diagnosis is Post Traumatic Stress Disorder (PTSD) and Anxiety Disorder (World Health Organization [WHO]), 2001). In this study we detect and categorize symptoms of post-traumatic stress disorder (PTSD) associated with coronavirus disease 2019 in a student population.  Article visualizations

Transport of fungal RAB11 secretory vesicles involves myosin-5, dynein/dynactin/p25, and kinesin-1 and is independent of kinesin-3

15 p.-8 fig.Hyphal tip cells of the fungus Aspergillus nidulans are useful for studying long-range intracellular traffic. Post-Golgi secretory vesicles (SVs) containing the RAB11 orthologue RabE engage myosin-5 as well as plus end– and minus end–directed microtubule motors, providing an experimental system with which to investigate the interplay between microtubule and actin motors acting on the same cargo. By exploiting the fact that depolymerization of F-actin unleashes SVs focused at the apex by myosin-5 to microtubule-dependent motors, we establish that the minus end–directed transport of SVs requires the dynein/dynactin supercomplex. This minus end–directed transport is largely unaffected by genetic ablation of the Hook complex adapting early endosomes (EEs) to dynein but absolutely requires p25 in dynactin. Thus dynein recruitment to two different membranous cargoes, namely EEs and SVs, requires p25, highlighting the importance of the dynactin pointed-end complex to scaffold cargoes. Finally, by studying the behavior of SVs and EEs in null and rigor mutants of kinesin-3 and kinesin-1 (UncA and KinA, respectively), we demonstrate that KinA is the major kinesin mediating the anterograde transport of SVs. Therefore SVs arrive at the apex of A. nidulans by anterograde transport involving cooperation of kinesin-1 with myosin-5 and can move away from the apex powered by dynein.This work was funded by grants from the Spanish Ministerio de Economía y Competitividad (BIO2012-30965 and BIO2015-65090-R) and the Comunidad de Madrid (Grant S2010/ BMD-2414) to M.A.P. and from the National Institutes of Health (RO1 GM097580) and the Uniformed Services University (intramural grant BIO-71-1972) to X.X.Peer reviewe

Boundary integral methods for acoustic scattering and radiation

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Mutational analysis and modeling reveal functionally critical residues in transmembrane segments 1 and 3 of the UapA transporter

Earlier, we identified mutations in the first transmembrane segment (TMS1) of UapA, a uric acid-xanthine transporter in Aspergillus nidulans, that affect its turnover and subcellular localization. Here, we use one of these mutations (H86D) and a novel mutation (I74D) as well as genetic suppressors of them, to show that TMS1 is a key domain for proper folding, trafficking and turnover. Kinetic analysis of mutants further revealed that partial misfolding and deficient trafficking of UapA does not affect its affinity for xanthine transport, but reduces that of uric acid and confers a degree of promiscuity towards the binding of other purines. This result strengthens the idea that subtle interactions among domains not directly involved in substrate binding refine the selectivity of UapA. Characterization of second-site suppressors of H86D revealed a genetic interaction of TMS1 with TMS3, the latter segment shown for the first time to be important for UapA function. Systematic mutational analysis of polar and conserved residues in TMS3 showed that Ser154 is crucial for UapA transport activity. Our results are in agreement with a topological model of UapA built on the recently published structure of UraA, a bacterial homolog of UapA

Microstructural characterization of high-performance steel fiber reinforced geopolymer concrete

Due to growing environmental and economic concerns associated with conventional building materials, research interest gravitates towards the development of novel environmentally friendly materials as alternatives to conventional Portland cement concrete. Geopolymer concrete is a class of novel advanced and sustainable structural materials that hold promise for the future of infrastructure. Its synthesis comprises industrial by-products (fly ash and slag among others) in the role of binder and thus reduces the demand in Portland cement leading to a significant carbon footprint reduction. In the present study a High-Performance Fiber Reinforced Geopolymer Concrete (HPFRGC) is synthesized from first principles and is subsequently characterized, with particular emphasis on its microstructural and mineralogical properties. The study explores the linkage between the microstructure and mineralogy of the precursors, and the properties of the final product. Both fresh and hardened HPFRGC are studied. Experimental results illustrate the correlation between microstructure, mineralogy and final mechanical properties can be used as an indicator of suitability of industrial by-products for geopolymer precursors. The effect of these choices on stability and physical properties of the material is also explored in the study

Global Interventions for Seismic Upgrading of Substandard RC Buildings

A methodology is developed in this paper for the design and proportioning of interventions for seismic upgrading of substandardreinforced-concrete (RC) buildings. The retrofit approach is presented in the form of a simple design tool that aims toward both demand reduction and enhancement of force and deformation supply through controlled modification of stiffness along the height of the building. This objective is achieved by engineering the translational mode-shape of the structure, so as to optimize the distribution of interstory drift. Resultsfrom the proposed approach are summarized in a spectrum format in which demand, expressed in terms of interstory drift, is related to stiffness. Design charts, which relate the characteristics of commonly used global intervention procedures to influence drift demands, are developed to facilitate the retrofit design. The intervention procedures considered in this paper are reinforced-concrete jacketing, the addition of reinforced concrete walls, and the addition of masonry infills. The proposed methodology is also amenable to adaptation to other strengthening methods, such as the addition of cross-bracing

Νοητική ευελιξία στην διπολική διαταραχή: Η επίδραση κλινικοδημογραφικών και φαρμακολογικών παραγόντων

ΕΙΣΑΓΩΓΗ: Στην διεθνή βιβλιογραφία παραμένει ακόμη ασαφές αν η νοητική ευελιξία επηρεάζεται αρνητικά στην Διπολική Διαταραχή (ΔΔ). Σύγχρονες μετααναλύσεις έχουν υποδείξει την ανάγκη περαιτέρω διερεύνησης της προβλεπτικής επίδρασης δημογραφικών, κλινικών και φαρμακολογικών παραγόντων ως προς την συγκεκριμένη λειτουργία, καθώς φαίνεται να συμβάλουν καθοριστικά στην πρόγνωση της πορείας των επιτελικών λειτουργιών στη νόσο. ΣΚΟΠΟΣ: Σκοπός της παρούσας έρευνας ήταν να μελετήσει τις διαφορές επίδοσης μεταξύ υγιών συμμετεχόντων και ασθενών με ΔΔ, ως προς την νοητική ευελιξία. Οι διενεργηθείσες αναλύσεις περιέλαβαν και την μελέτη του χρόνου απόκρισης, καθώς δεν έχει διερευνηθεί επαρκώς. Επιπροσθέτως, εξετάστηκαν οι πιθανές προβλεπτικές επιδράσεις κλινικοδημογραφικών και φαρμακολογικών παραγόντων ως προς την επίδοση των ασθενών στην νοητική ευελιξία. ΜΕΘΟΔΟΙ: Στην μελέτη συμμετείχαν 90 νορμοθυμικοί ασθενείς με ΔΔ και 37 υγιείς συμμετέχοντες, στους οποίους αρχικά χορηγήθηκαν διαγνωστικές κλίμακες και ακολούθως η δοκιμασία Intra/ Extra Dimensional Set Shift (IED), από την συστοιχία της Cambridge Neuropsychological Test Automated Battery (CANTAB), η οποία αποτελεί την πιο αντιπροσωπευτική δοκιμασία αξιολόγησης της νοητικής ευελιξίας. Επιλέχθηκαν κατάλληλα στατιστικά μοντέλα (Poisson/Negative Binomial Regression, Linear Regression) και διενεργήθηκαν μονομεταβλητές και πολυμεταβλητές αναλύσεις προκειμένου να διερευνηθούν οι διαφορές επίδοσης μεταξύ μαρτύρων/ασθενών (διόρθωση ως προς φύλο/ηλικία/εκπαίδευση) και να εξεταστούν οι προβλεπτικές επιδράσεις κλινικοδημογραφικών και φαρμακολογικών παραγόντων ως προς πέντε βασικές εκβάσεις του IED (Total errors adjusted, Total trials adjusted, Stages Completed, Total Latency, Standard Deviation latency). ΑΠΟΤΕΛΕΣΜΑΤΑ: Βρέθηκε στατιστικώς σημαντική διαφορά μεταξύ ασθενών/ υγιών ως προς τον χρόνο απόκρισης (ασθενείς>υγιείς), όμως μετά από διόρθωση Bonferroni το εύρημα επιβίωσε μόνο στις αναλύσεις με Mann-Whitney αλλά όχι όταν πραγματοποιήθηκε διόρθωση ως προς φύλο/ηλικία/εκπαίδευση με γραμμική παλινδρόμηση. Στις πολυμεταβλητές αναλύσεις στατιστικώς σημαντική αρνητική επίδραση στη δοκιμασία είχαν: δημογραφικοί παράγοντες (θήλυ φύλο, ηλικία), η καταθλιπτική πολικότητα 1ου επεισοδίου, ο αριθμός υπερθυμικών επεισοδίων, η συγγένεια 1ου βαθμού με άτομο με διάγνωση σχιζοφρένειας και η ύπαρξη υποκλινικών καταθλιπτικών συμπτωμάτων. ΣΥΜΠΕΡΑΣΜΑΤΑ: Οι ασθενείς με ΔΔ παρουσιάζουν πιθανώς ελλειμματική νοητική ευελιξία ως προς τον χρόνο απόκρισης. Δημογραφικοί παράγοντες, η καταθλιπτική πολικότητα 1ου επεισοδίου, ο αριθμός υπερθυμικών επεισοδίων, η συγγένεια 1ου βαθμού με άτομο με διάγνωση σχιζοφρένειας και η ύπαρξη υποκλινικών καταθλιπτικών συμπτωμάτων αποτελούν τους βασικότερους προβλεπτικούς παράγοντες για την εμφάνιση προβληματικής επίδοσης των ασθενών με ΔΔ στην νοητική ευελιξία, είτε ως προς την ακρίβεια απόδοσης είτε ως προς τον χρόνο απόκρισης.INTRODUCTION: It is not yet clear whether cognitive flexibility is adversely affected in bipolar disorder (BD). Meta-analyses have suggested the need to further investigate the effect of demographic, clinical and pharmacological factors on this function, as they seem to significantly predict the trajectory of executive functions in BD. PURPOSE: The aim of the present study was to investigate the performance between healthy subjects and patients with BD, in terms of cognitive flexibility. The analyses performed also included the study of Total Latency as it has not been adequately investigated. In addition, potential predictive effects of clinical, demographic and pharmacological factors on patients’ performance were examined. METHOD: The study included 90 euthymic patients with BD and 37 healthy individuals. Participants were subjected to diagnostic evaluation and administration of the Intra/ Extra Dimensional Set Shift (IED) test, included in Cambridge Neuropsychological Test Automated Battery (CANTAB), which is regarded as the most representative test for assessing cognitive flexibility. Appropriate statistical models (Poisson/Negative Binomial Regression, Linear Regression) were selected for Univariate and Multivariate analyses to investigate differences in performance between groups (adjusted for gender/age/education). Predictive effects of clinical, demographic and pharmacological factors on five IED main outcomes (Total errors adjusted, Total trials adjusted, Stages Completed, Total Latency, Standard Deviation latency) were also examined. RESULTS: Patients with BD had significantly higher Total Latency compared to controls. When Bonferroni correction was applied, the finding survived only in Mann Whitney analyses but not in adjusted analyses (for age/education/gender with Linear Regression). In Multivariate analyses, the following factors had a negative significant effect on IED performance: demographic factors (female sex, age), depressive onset polarity, number of hyperthymic episodes, family history of schizophrenia in 1st degree relatives and sub-clinical depressive symptoms. CONCLUSION: BD patients may demonstrate deficits in cognitive flexibility in terms of Total Latency. Demographic factors, depressive onset polarity, higher number of hyperthymic episodes, a 1st degree relative diagnosed with schizophrenia and subclinical depressive symptoms appear to have a significant predictive value for inadequate performance of BD patients in cognitive flexibility, in terms of either performance accuracy or total latency