Numerical simulation of bed evolution dynamics: the Pescara harbor

A two-dimensional phase resolving model is used for the computation of the hydrodynamic field in wave-current interaction in the sea regions opposite to the Pescara harbor. The total sediment transport is given by the contribution of the suspended sediment load, calculated by solving the advection-diffusion equation for the suspended sediment concentration, and of the spatial variation of the bed load transport. The proposed model has been used to simulate the silting phenomenon occurring in the sea region opposite to the Pescara harbor in presence of coastal defense structures

Characterization of the retinal neurovascular unit in zebrafish

In recent years, zebrafish (Danio rerio) have become an established model to study retinal diseases. Most of the research in zebrafish has focused on vascular and neu-ronal pathologies. However, in many retinal diseases, such as diabetic retinopathy, the entirety of the neurovascular unit, which includes retinal neuronal cells, retinal macro-glia (especially Müller glial cells) and microglia and retinal vascular cells (endothelial cells and vascular mural cells/pericytes), is disrupted. Therefore, this study aimed to analyse whether all components of the neurovascular unit are present in the zebrafish retina and to establish methods which can be used to analyse the neurovascular unit in the zebrafish retina. Those methods were then used to analyse the retinae of pdx1+/- zebrafish mutants, which have gained interest as a potential model for pathologies associated with diabetic retinopathy. The methodical approach to analyse loss of neuronal cells in mammalian retinae could be performed on zebrafish without alterations of the protocol. The retinae of pdx1+/- zebrafish were analysed at three different time points throughout adulthood: 4 months post fertilization (mpf), 12mpf and 20mpf. At 4mpf and 12mpf the overall retinal layer thickness was decreased. However, this change did not persist until 20mpf, which in-dicated that some form of regeneration was taking place in the zebrafish retina, making it difficult to evaluate potential changes. To analyse whether there were signs of regeneration, we performed an antibody stain for PCNA (proliferating cell nuclear antigen), an established marker for proliferation in the zebrafish retina. However, there was no increase in proliferating cells in the retinae of pdx1+/- zebrafish. We found that while in mammals Müller glia only express glial fibrillary acidic protein (GFAP) once they become activated, in zebrafish Müller glia cells always express GFAP. Therefore, to evaluate whether there was increased Müller glial activation, we had to modify the established protocol. Instead of analysing whether Müller glia ex-press GFAP, we counted and compared the number of GFAP-positive cells. In the pdx1+/- retina, we could find no difference between mutants and controls. L-Plastin was used as a marker to identify microglia. There was no increase in L-Plastin positive cells in the retinae of pdx1+/- zebrafish. Previous work has shown angiogenesis in the pdx1+/- retina at 18mpf. To evaluate whether the vascular cells were affected to explain this phenomenon, we adapted the retinal trypsin digest protocol to the zebrafish retina. After identification of the different cell types which are visible in the zebrafish retinal trypsin digest preparation the aver-age number of endothelial cells and vascular mural cells per square millimetre in the adult zebrafish retina were established. However, in comparison to controls, pdx1+/- mutants did not suffer any pericyte or endothelial cell loss. In conclusion, we can show that all components of the neurovascular unit which have been identified in the mammalian retina are present in zebrafish as well. However, at least in the pdx1+/- zebrafish line, they do not seem to interact in a way that would be expected from mammalian models. This indicates that the reaction of the zebrafish retina to hyperglycaemic environmental conditions most likely differs from mechanisms known from mammalian models and needs further investigation. To facilitate future work on the zebrafish retina, this thesis provides detailed and comprehensive protocols to analyse the retinal neurovascular unit in the zebrafish retina

Biotin-anandamide: a new tool to visualize anandamide inside the cells

L’endocannabinoide anandamide è un lipide neuromodulatorio non carico che è inattivato grazie al suo assorbimento cellulare e successivo catabolismo. Mentre la biosintesi e la degradazione dell’anandamide sono state chiarite in dettaglio, il meccanismo attraverso cui essa entra all’interno della cellula rimane ancora non chiaro. Vi è un generale accordo solo sul fatto che il movimento dell’anandamide attraverso la membrana plasmatica è rapido, ha una cinetica di saturazione ed è temperatura dipendente. Mentre molti sono gli studi che descrivono un assorbimento mediato da uno specifico trasportatore di questo endocannabinoide, solo pochi lavori hanno proposto che il trasporto avvenga attraverso semplice diffusione passiva o attraverso endocitosi mediata da caveolae/lipid rafts. L’unica cosa certa però ad oggi è che, la mancanza del clonaggio e dell’espressione di questa ipotetica proteina trasportatrice, ha impedito lo sviluppo di strumenti molecolari che potrebbero dare una definitiva risposta della reale presenza di un trasportatore sulla superficie cellulare. Allo stesso tempo, non sono ancora stati messi a punto analoghi dell’anandamide che ci consentano di visualizzare i suoi movimenti attraverso la membrana plasmatica e di conseguenza il suo destino all’interno della cellula. Il nostro gruppo ha sintetizzato e caratterizzato un analogo dell’anandamide (b-AEA) che possiede la stessa lipofilia del composto madre. Abbiamo usato metodi biochimici e di microscopia impiegando la b-AEA come strumento per visualizzare l’accumulo, la distribuzione ed i movimenti intracellulari dell’anandamide. Abbiamo scelto di modificare la testa polare della molecola poiché questo cambiamento strutturale non influenza la cinetica del trasporto. I nostri studi ci hanno consentito di chiarire la presenza di strutture intracellulari dette adiposomi, che possono accumulare anandamide e che potrebbero essere coinvolti nel suo trasporto verso la FAAH. Usando la nostra molecola biotinilata abbiamo inoltre identificato due proteine citosoliche, l’albumina e la Hsp70.2, come potenziali trasportatori che legano l’anandamide e che potrebbero formare un sistema di trasporto in grado di consentire, in modo veloce ed efficiente, il movimento dell’anandamide all’interno della cellula.The endocannabinoid anandamide is an uncharged neuromodulatory lipid that is inactivated through its cellular uptake and subsequent catabolism. While the biosynthesis and degradation of AEA have been clarified in considerable detail, the mechanism of AEA uptake has remained elusive. There is a general consensus only on the fact that AEA movement through the plasma membrane is rapid, saturable, temperature-dependent. While many studies describe a transporter-mediated uptake of AEA via a selective “anandamide membrane transporter”, only a few papers proposed that the transport occurs by simple diffusion or endocytosis via caveolae/lipid rafts. As a matter of fact, the lack of cloning and expression of the purported transporter protein has prevented the development of molecular tools which could give definitive proof of the presence of a true transporter on the cell surface. In the same line, AEA analogs able to visualize AEA movement across the plasma membrane and its subsequent fate within the cell, are still missing. We synthesized and characterized a biotinylated analog of AEA (biotin-AEA) that has the same lipophilicity of the parent compound. We used biochemical assays and fluorescence microscopy employing b-AEA as a tool to visualize accumulation, intracellular distribution and trafficking of AEA inside the cells. We chose to modify the polar head of AEA because this structural change does not influence the kinetics of AEA uptake. Our studies led us to clarify the presence of molecular structures, the adiposomes, as a way to accumulate AEA and that could be involved in its delivery to FAAH. Using our biotinylated probe, we also identified two cytosolic proteins (albumin and Hsp70.2) as potential AEA-binding carriers which might form a delivery system to rapidly and efficiently assist the intracellular trafficking of AEA

Full characterization of the quantum linear-zigzag transition in atomic chains

A string of repulsively interacting particles exhibits a phase transition to a zigzag structure, by reducing the transverse trap potential or the interparticle distance. The transition is driven by transverse, short wavelength vibrational modes. Based on the emergent symmetry Z_2 it has been argued that this instability is a quantum phase transition, which can be mapped to an Ising model in transverse field. We perform an extensive Density Matrix Renormalization Group analysis of the behaviour at criticality and evaluate the critical exponents and the central charge with high precision. We thus provide strong numerical evidence confirming that the quantum linear-zigzag transition belongs to the critical Ising model universality class. These results show that structural instabilities of one-dimensional interacting atomic arrays can simulate quantum critical phenomena typical of ferromagnetic systems.Comment: 5 pages, 4 figure

Epidemiology, risk factors and therapy of candidemia in pediatric hematological patients

Invasive fungal infections (IFI) are an important cause of morbidity, increased hospitalization and healthcare costs in critically ill or immunocompromised children. The mortality is comprised between 5 and 20%. In the last 2 decades, the epidemiology of candidemia has changed with an increase of episodes caused by non-Candida albicans species. Central venous catheter, diagnosis of malignancy, and receipt of either vancomycin or antimicrobials with activity against anaerobic organisms for >3 days have been associated with the development of candidemia in the pediatric intensive care unit (PICU). Additional risk factors found in hematological patients were the diagnosis of aplastic anemia, performing an unrelated bone marrow or cord blood transplant, the occurrence of a graft versus host disease and the use of steroids. Early antifungal treatment is recommended to reduce mortality. In neutropenic patients, liposomal amphotericin B, an echinocandin (caspofungin, micafungin), and voriconazole are considered the best option especially for C. glabrata and C. krusei. Fluconazole remains a valid option for infection by Candida albicans in patients not exposed to fluconazole prophylaxis. Amphotericn B deoxy-cholate is generally not recommended because of its nephrotoxicity

Memory NK cell features exploitable in anticancer immunotherapy

Besides their innate ability to rapidly produce effector cytokines and kill virus-infected or transformed cells, natural killer (NK) cells display a strong capability to adapt to environmental modifications and to differentiate into long-lived, hyperfunctional populations, dubbed memory or memory-like NK cells. Despite significant progress in the field of NK cell-based immunotherapies, some factors including their short life span and the occurrence of a tumor-dependent functional exhaustion have limited their clinical efficacy so that strategies aimed at overcoming these limitations represent one of the main current challenges in the field. In this scenario, the exploitation of NK cell memory may have a considerable potential. This article summarizes recent evidence in the literature on the peculiar features that render memory NK cells an attractive tool for antitumor immunotherapy, including their long-term survival and in vivo persistence, the resistance to tumor-dependent immunosuppressive microenvironment, the amplified functional responses to IgG-opsonized tumor cells, and in vitro expansion capability. Along with highlighting these issues, we speculate that memory NK cell-based adoptive immunotherapy settings would greatly take advantage from the combination with tumor-targeting therapeutic antibodies (mAbs), as a strategy to fully unleash their clinical efficacy

Videocapillaroscopy in Connective Tissue Diseases

Videocapillaroscopy is a noninvasive, quick, and easy examination method to indicate if there is clinical suspicion of microangiopathy. It provides the rheumatologist indispensable information on the microcirculation state. Recently with the development of the new classification criteria of systemic sclerosis (ACR 2013), capillaroscopy has become even more important. It is currently the only instrumental test whose result is pathognomonic for diagnosis of systemic sclerosis. During videocapillaroscopy, the following parameters are evaluated: density, structure, hemosiderin deposition, bloodstream, presence of megacapillaries, presence of subpapillary venous plexus, and edema. It can distinguish several patterns, especially scleroderma pattern, as follows: (1) “Early” pattern: few enlarged/giant capillaries, few capillary hemorrhages, relatively well‐preserved capillary distribution, no evident loss of capillaries; (2) “Active” pattern: frequent giant capillaries, frequent capillary hemorrhages, moderate loss of capillaries, mild disorganization of the capillary architecture, absent or mild ramified capillaries; (3) “Late” pattern: irregular enlargement of the capillaries, few or absent giant capillaries and hemorrhages, severe loss of capillaries with extensive avascular areas, disorganization of the normal capillary array, ramified/bushy capillaries. Although capillaroscopic examination is easy to perform, it is essential that the operator has been properly trained on the instrument’s function and on correct method of image acquisition to avoid misinterpretation