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

Spotlight on islands.On the origin and diversification of an ancient lineage of the Italian wall lizard Podarcis siculus in the western Pontine Islands

Groups of proximate continental islands may conceal more tangled phylogeographic patterns than oceanic archipelagos as a consequence of repeated sea level changes, which allow populations to experience gene flow during periods of low sea level stands and isolation by vicariant mechanisms during periods of high sea level stands. Here, we describe for the first time an ancient and diverging lineage of the Italian wall lizard Podarcis siculus from the western Pontine Islands. We used nuclear and mitochondrial DNA sequences of 156 individuals with the aim of unraveling their phylogenetic position, while microsatellite loci were used to test several a priori insular biogeographic models of migration with empirical data. Our results suggest that the western Pontine populations colonized the islands early during their Pliocene volcanic formation, while populations from the eastern Pontine Islands seem to have been introduced recently. The inter-island genetic makeup indicates an important role of historical migration, probably due to glacial land bridges connecting islands followed by a recent vicariant mechanism of isolation. Moreover, the most supported migration model predicted higher gene flow among islands which are geographically arranged in parallel. Considering the threatened status of small insular endemic populations, we suggest this new evolutionarily independent unit be given priority in conservation efforts

Cloning transformations in spin networks without external control

In this paper we present an approach to quantum cloning with unmodulated spin networks. The cloner is realized by a proper design of the network and a choice of the coupling between the qubits. We show that in the case of phase covariant cloner the XY coupling gives the best results. In the 1->2 cloning we find that the value for the fidelity of the optimal cloner is achieved, and values comparable to the optimal ones in the general N->M case can be attained. If a suitable set of network symmetries are satisfied, the output fidelity of the clones does not depend on the specific choice of the graph. We show that spin network cloning is robust against the presence of static imperfections. Moreover, in the presence of noise, it outperforms the conventional approach. In this case the fidelity exceeds the corresponding value obtained by quantum gates even for a very small amount of noise. Furthermore we show how to use this method to clone qutrits and qudits. By means of the Heisenberg coupling it is also possible to implement the universal cloner although in this case the fidelity is 10% off that of the optimal cloner.Comment: 12 pages, 13 figures, published versio

From perfect to fractal transmission in spin chains

Perfect state transfer is possible in modulated spin chains, imperfections however are likely to corrupt the state transfer. We study the robustness of this quantum communication protocol in the presence of disorder both in the exchange couplings between the spins and in the local magnetic field. The degradation of the fidelity can be suitably expressed, as a function of the level of imperfection and the length of the chain, in a scaling form. In addition the time signal of fidelity becomes fractal. We further characterize the state transfer by analyzing the spectral properties of the Hamiltonian of the spin chain.Comment: 8 pages, 10 figures, published versio

Nonequilibrium critical scaling from quantum thermodynamics

The emerging field of quantum thermodynamics is contributing important results and insights into archetypal many-body problems, including quantum phase transitions. Still, the question whether out-of-equilibrium quantities, such as fluctuations of work, exhibit critical scaling after a sudden quench in a closed system has remained elusive. Here, we take a novel approach to the problem by studying a quench across an impurity quantum critical point. By performing density matrix renormalization group computations on the two-impurity Kondo model, we are able to establish that the irreversible work produced in a quench exhibits finite-size scaling at quantum criticality. This scaling faithfully predicts the equilibrium critical exponents for the crossover length and the order parameter of the model, and, moreover, implies a new exponent for the rescaled irreversible work. By connecting the irreversible work to the two-impurity spin correlation function, our findings can be tested experimentally.Comment: 6 pages, 4 figure

Advanced-Metastatic Non-Small-Cell Lung Cancer EGFR-mutated in Italy: patient management costs and potential productivity losses:

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are established therapies for previously untreated advanced/metastatic non-small cell lung cancer (NSCLC) EGFR-mutated patients. Osimertinib, a third-generation TKI, has recently received the same first-line indication. This study aims at investigating management costs and potential productivity losses in Italy in this patient setting, given all the available therapeutic options. Two analyses were performed. The first evaluates first-line yearly management costs and potential productivity losses per patient, for each first-line treatment. The second, performed nationally and regionally, models all lines of treatments and costs over a five-year period, through different market-share scenarios – considering osimertinib adoption as new therapy in 60% of patients as the most probable one – and line-switch/mortality probabilities. Using this model, patients' total months of treatment and development/progression of brain metastases were also analyzed. The first analysis shows that first-line management costs and potential productivity losses are minimized by osimertinib (first-line yearly expenditure of €25.942, 8%-12% less than TKIs). The second analysis, based on a five-year horizon and on all therapy lines, shows that total management costs and potential productivity losses decrease by increasing the adoption of osimertinib as a first-line therapy (€7.4m cumulative lower cost with osimertinib at 60% compared to 0%). Considering the average month of therapy, where results are not affected by the length of the therapy, with osimertinib at 60% on naïve patients, monthly management costs and productivity losses are 10% lower than in the non-osimertinib scenario. In advanced, metastatic EGFR-mutated NSCLC, the use of osimertinib as the first-line treatment could reduce patient management costs and potential productivity losses

HCC in Cirrhotic and Non-cirrhotic Liver: Timing to Surgery and Outcome - State of the Art

In this chapter we aim at presenting the state of the art in liver surgery. After a brief introduction about natural evolution of hepatocellular carcinoma (HCC) either in cirrhotic or non-cirrhotic patients, this manuscript will focus on planning and timing surgery: CT evaluation of the remnant liver; biopsy and ultrasonography (US) evaluation of liver disease; intraoperative US; surgical techniques, such as major and limited hepatectomies and two-stage hepatectomies, each of them in open or mini-invasive approach; and their possible complications. Follow-up and further interventions during expected recurrences will be highlighted. Our chapter will also treat topics such as patient’s quality of life, importance of multidisciplinary evaluation and the role of surgeon in it

NO scavenging through reductive nitrosylation of ferric Mycobacterium tuberculosis and Homo sapiens nitrobindins

Ferric nitrobindins (Nbs) selectively bind NO and catalyze the conversion of peroxynitrite to nitrate. In this study, we show that NO scavenging occurs through the reductive nitrosylation of ferric Mycobacterium tuberculosis and Homo sapiens nitrobindins (Mt-Nb(III) and Hs-Nb(III), respectively). The conversion of Mt-Nb(III) and Hs-Nb(III) to Mt-Nb(II)-NO and Hs-Nb(II)-NO, respectively, is a monophasic process, suggesting that over the explored NO concentration range (between 2.5 × 10-5 and 1.0 × 10-3 M), NO binding is lost in the mixing time (i.e., NOkon ≥ 1.0 × 106 M-1 s-1). The pseudo-first-order rate constant for the reductive nitrosylation of Mt-Nb(III) and Hs-Nb(III) (i.e., k) is not linearly dependent on the NO concentration but tends to level off, with a rate-limiting step (i.e., klim) whose values increase linearly with [OH-]. This indicates that the conversion of Mt-Nb(III) and Hs-Nb(III) to Mt-Nb(II)-NO and Hs-Nb(II)-NO, respectively, is limited by the OH--based catalysis. From the dependence of klim on [OH-], the values of the second-order rate constant kOH- for the reductive nitrosylation of Mt-Nb(III)-NO and Hs-Nb(III)-NO were obtained (4.9 (±0.5) × 103 M-1 s-1 and 6.9 (±0.8) × 103 M-1 s-1, respectively). This process leads to the inactivation of two NO molecules: one being converted to HNO2 and another being tightly bound to the ferrous heme-Fe(II) atom