2007, Articolo in rivista, ENG
Zaniboni, Massimiliano; Cacciani, Francesca; Salvarani, Nicolò
Adaptation of action potential duration (APD) to pacing cycle length (CL) has been previously characterized in isolated cardiomyocytes for sudden changes in constant CL and for pre-/postmature stimuli following constant pacing trains. However, random fluctuations characterize both physiological sinus rhythm (up to 10% of mean CL) and intrinsic beat-to-beat APD at constant pacing rate. We analysed the beat-to-beat sensitivity of each APD to the preceding CL during constant-sudden, random or linearly changing pacing trains in single patch clamped rat left ventricular myocytes, in the absence of the autonomic and electrotonic effects that modulate rate dependency in the intact heart. Beat-to-beat variability of APD at -60 mV (APD), quantified as s.d. over 10-beat sequences, increased with corresponding mean APD. When measured as coefficient of variability (CV), APD variability was inversely proportional to pacing frequency (from 1.2% at 5 Hz to 3.2% at 0.2 Hz). It was increased, at a basic CL (BCL) of 250 ms, by 55% by the L-type calcium current (I) blocker nifedipine, and decreased by 23% by the transient-outward potassium current (I) blocker 4-aminopyridine. Variability of APD at BCL of 250 ms prevented the detection of random changes of CL smaller than ~5%. Ten per cent random changes in CL were detected as a 40% increase in CV of APD and tended to correlate with it (r = 0.43). Block of I depressed this correlation (r = 0.23), whereas block of I significantly increased it (r = 0.67); this was similar with linearly changing CL ramps (ranging ±10% and ±20% of 250 ms). We conclude that beat-to-beat APD variability, a major determinant of the propensity for development of arrhythmia in the heart, is present in isolated myocytes, where it is dependent on mean APD and pacing rate. Action potential duration shows a beat-to-beat positive correlation with preceding randomly/linearly changing CL, which can be pharmacologically modulated. © 2007 The Authors.
2007, Articolo in rivista, ENG
Miragoli, Michele; Salvarani, Nicolò; Rohr, Stephan
Focal ectopic activity in cardiac tissue is a key factor in the initiation and perpetuation of tachyarrhythmias. Because myofibroblasts as present in fibrotic remodeled myocardia and infarct scars depolarize cardiomyocytes by heterocellular electrotonic interactions via gap junctions in vitro, we investigated using strands of cultured ventricular cardiomyocytes coated with myofibroblasts, whether this interaction might give rise to depolarization- induced abnormal automaticity. Whereas uncoated cardiomyocyte strands were invariably quiescent, myofibroblasts induced synchronized spontaneous activity in a density dependent manner. Activations appeared at spatial myofibroblast densities >15.7% and involved more than 80% of the preparations at myofibroblast densities of 50%. Spontaneous activity was based on depolarization-induced automaticity as evidenced by: (1) suppression of activity by the sarcolemmal KATP channel opener P-1075; (2) induction of activity in current-clamped single cardiomyocytes undergoing depolarization to potentials similar to those induced by myofibroblasts in cardiomyocyte strands; and (3) induction of spontaneous activity in cardiomyocyte strands coated with connexin 43 transfected Hela cells but not with communication deficient HeLa wild-type cells. Apart from unveiling the mechanism underlying the hallmark of monolayer cultures of cardiomyocytes, ie, spontaneous electromechanical activity, these findings open the perspective that myofibroblasts present in structurally remodeled myocardia following pressure overload and infarction might contribute to arrhythmogenesis by induction of ectopic activity. © 2007 American Heart Association, Inc.
2007, Articolo in rivista, ENG
Angius, Andrea; Simpore, Jacques; Persico, Ivana; Sassu, Alessandro; Prodi, Dionigio Antonio; Musumeci, Salvatore
In Burkina Faso the levels of plasma homocysteine (Hcy) are lower and the methionine loading tests suggest a more effective Hcy metabolism. The polymorphisms of methylenetetrahydrofolate reductase (MTHFR) showed a relevant difference in the allele frequencies of T MTHFR-677 in young and in old subjects, while the allele frequency of C MTHFR-1298 was comparable in young and old subjects. The aim of this paper was to study the impact of the MTHFR polymorphisms on plasma fasting Hcy and after methionine loading in Burkina Faso. The young subjects with CC MTHFR-677 genotype had levels of Hey significantly lower than CT and TT subjects. The level of Hcy in subjects who had AA, AC and CC MTHFR-1298 genotypes were comparable. The levels of Hcy after the methionine loading test were significantly higher in CT and TT MTHFR-677 genotype. These results suggest that the genetic situation in Burkina Faso is different from that of other Western countries and this guarantees the maintenance of lower plasma levels of Hcy in young and old Africans. The elevated levels of plasma Hcy in old subjects compared to young subjects, against the IoNN prevalence of the T allele in elderly subjects, is discussed.
2007, Articolo in rivista, ENG
Angius, Andrea; Hyland, Fiona C.L.; Persico, Ivana; Pirastu, Nicola; Woodage, Trevor; Pirastu, Mario; De La Vega, Francisco M.
Objective: In isolated populations, 'background' linkage disequilibrium (LD) has been shown to extend over large genetic distances. This and their reduced environmental and genetic heterogeneity has stimulated interest in their potential for association mapping. We compared LD unit map distances with pair-wise measurements of LD in a dense single nucleotide polymorphism (SNP) set. Methods: We genotyped 771 SNPs in an 8 Mb segment of chromosome 22 on 101 individuals from the isolated village of Talana, Sardinia, and compared with outbred European populations. Results: Heterozygosity was remarkably similar in both populations. In contrast, the extent of LD observed was quite different. The decay of LD with distance is slower in the isolate. The differences in LD map lengths suggest that useful LD extends up to three times farther in the Sardinian population; smaller differences are seen with pairwise LD metrics. While LD map length slightly decreases with average relatedness, cryptic relatedness does not explain the decrease in LD map length. Haplotypes, block boundaries, and patterns of LD are similar in both populations, suggesting a shared distribution of recombination hotspots. Conclusions: About 15% fewer haplotype tagging SNPs need to be genotyped in the isolate, and possibly 70% fewer if selecting SNPs evenly spaced on the metric LD map. Copyright © 2008 S. Karger AG.
2007, Articolo in rivista, ENG
Apollonio N, Franciosa P G
Can a directed graph be completed to a directed line graph? If possible, how many arcs must be added? In this paper we address the above questions characterizing partial directed line (PDL) graphs, i.e., partial subgraph of directed line graphs. We show that for such class of graphs a forbidden configuration criterion and a Krausz's like theorem are equivalent characterizations. Furthermore, the latter leads to a recognition algorithm that requires worst case time, where m is the number of arcs in the graph. Given a partial line digraph, our characterization allows us to find a minimum completion to a directed line graph within the same time bound. The class of PDL graphs properly contains the class of directed line graphs, characterized in [J. Blazewicz, A. Hertz, D. Kobler, D. de Werra, On some properties of DNA graphs, Discrete Appl. Math. 98(1-2) (1999) 1-19], hence our results generalize those already known for directed line graphs. In the undirected case, we show that finding a minimum line graph edge completion is NP-hard, while the problem of deciding whether or not an undirected graph is a partial graph of a simple line graph is trivial.
2007, Articolo in rivista, ENG
Bolzati, Cristina; Caporale, Andrea; Agostini, Stefania; Carta, Davide; Cavazza-Ceccato, Mario; Refosco, Fiorenzo; Tisato, Francesco; Schievano, Elisabetta; Bandoli, Giuliano
Using the avidin-biotin system as model, we investigate here the effective application of [Tc(N)L(PNP)]+/0 technology (L=N-functionalized cysteine [O-,S-]; PNP=aminodiphosphine) to the preparation of target-specific radiopharmaceuticals. A series of 99mTc-nitrido complexes containing functionalized biotin ligands was prepared and their biological profile was determined. To minimize the steric and the electronic influences of the Tc-carrying complex on the biotin-avidin receptor interaction, the following N-functionalized cysteine-biotin derivatives were synthesized: (1) Biot-CysOSH; (2) Biot-Abu-CysOSH; (3) Biot-Abz-CysOSH; (4) Biot-l-(Ac)Lys-CysOSH; (5) Biot-d-(Ac)Lys-CysOSH; (6) Biot-Glu-CysOSH. The asymmetrical nitrido-Tc(V) 99g/99mTc(N)(Biot-X-CysOS)(PNP3) (X=spacer) complexes, where PNP3 was N,N-bis-[(dimethoxypropyl)phosphinoethyl] methoxy-ethylamine, were obtained by simultaneous addition of PNP3 and the relevant biotinylated ligand to a solution containing a 99mTc-nitrido precursor (yields >95%). In all cases, a mixture of syn- and anti isomers was observed. In vitro challenge experiments with glutathione and cysteine indicated that no transchelation reactions occurred. Assessment of the in vitro binding to avidin of the complexes revealed that only the complexes containing Biot-Abu-CysOS and Biot-Glu-CysOS ligand maintained a good affinity for the concentrator. Stability studies carried out in human and mouse plasma as well as in rat and mouse liver homogenate evidenced a rapid enzymatic degradation for the 99mTc(N)(Biot-Abu-CysOS)(PNP3) complex, whereas the 99mTc(N)(Biot-Glu-CysOS)(PNP3) one was stable in all conditions. Tissue biodistribution in normal Balb/C mice of the most stable candidate showed a rapid clearance both from the blood and the other tissues. The activity was eliminated both through the hepatobiliary system and the urinary tract.
2007, Articolo in rivista, ENG
Fiori, Nereo; Caporale, Andrea; Schievano, Elisabetta; Mammi, Stefano; Geyer, Armin; Tremmel, Peter; Wittelsberger, Angela; Woznicz, Iwona; Chorev, Michael; Peggion, Evaristo
The N-terminal 1-34 fragment of parathyroid hormone (PTH) is fully active in vitro and in vivo and reproduces all biological responses characteristic of the native intact PTH. In order to develop safer and non-parenteral PTH-like bone anabolic agents, we have studied the effect of introducing conformationally constrained dipeptide mimetics into the N-terminal portion of PTH in an effort to generate miniaturized PTH-mimetics. To this end, we have synthesized and conformationally and biologically characterized PTH(1-11) analogues containing 3R-carboxy-6S-amino-7,5-bicyclic thiazolidinlactam (7,5-bTL), a rigidified dipeptide mimetic unit. The wild type sequence of PTH(1-11) is H-Ser-Val-Ser-Glu-Ile-Gln-Leu-Met-His-Asn-Leu-NH2. The following pseudo-undecapeptides were prepared: [Ala1, 7,5-bTL3,4, Nle8, Arg11]hPTH(1-11)NH2 (I); [Ala1, 7,5-bTL6,7, Nle8, Arg11]hPTH(1-11)NH2 (II); [Ala1, Nle8, 7,5-bTL9,10, Arg11]hPTH(1-11)NH2 (III). In aqueous solution containing 20% TFE, only analogue I exhibited the typical CD pattern of the ?-helical conformation. NMR experiments and molecular dynamics calculations located the ?-helical stretch in the sequence Ile5-His9. The dipeptide mimetic unit 7,5-bTL induces a type III ?-turn, occupying the positions i - 1 and i of the turn. Analogue II exhibited an equilibrium between a type I ?-turn and an ?-helix, and analogue III did not show any ordered structure. Biological tests revealed poor activity for all analogues (EC50 > 0. 1 mM). Apparently, the relative side-chain orientation of Val2, Ile5 and Met8 can be critical for effective analogue-receptor interaction. Considering helicity as an essential property to obtain active PTH agonists, one must decorate the correctly positioned dipeptide mimetic azabicycloalkane scaffold with substitutions corresponding to the displaced amino acid.
2007, Articolo in rivista, ITA
FRANCO ORTOLANI, SILVANA PAGLIUCA
Le ricerche, stimolate dall'osservazione di numerose discontinuità fisiche significative, evidenti in molte sezioni stratigrafiche, sono state effettuate per gettare luce sul significato climatico dei differenti tipi di sedimenti accumulatisi negli ultimi 2500 anni che ricoprono numerosi siti archeologici, non influenzabili dagli interventi umani, di età compresa tra il Periodo Arcaico ed il Medioevo, ubicati a diverse latitudini e in aree geografiche con differenti condizioni morfoclimatiche. Le aree studiate sono comprese tra la Pianura del fiume Po (circa 45° N di latitudine) e il Nord Africa (Egitto) a circa 30-31° N di latitudine; le sezioni geoarcheologiche più complete e significative sono state studiate nelle pianure alluvionali e nelle dune costiere
2007, Articolo in rivista, ENG
Boari E.[1], Conticelli S.[1,2]
In the Middle Latin Valley, in the Roman Magmatic Province, southern Italy, volcanism developed during the Late Pleistocene, with eruption of high-Mg magmas characterized by a low content of phenocrysts. Small volumes of magma, transported to the surface rapidly, favored by an extensional post-collision regime, led to small monogenetic centers aligned along two main tectonic trends. The absence of a large magmatic reservoir allowed the occurrence of a fairly large amount of mafic, strongly primitive volcanic rocks with a fairly large enrichment in potassium. They range in composition from plagioclase-free ultrapotassic melilite-bearing (kamafugites) to ultrapotassic leucitites and plagioclase leucitites, to trachybasalts (shoshonites), and calc-alkaline basaltic rocks (subalkaline). The composition of minerals from the four different groups of rock is reported. The Fe-Mg distribution between olivine crystals and whole rocks indicates equilibrium crystallization. The clinopyroxene shows the typical trend of alkaline potassic and Ultrapotassic rocks, ranging in composition from diopside to hedenbergite. Melilite-bearing ultrapotassic rocks are found beside feldspar-bearing ultrapotassic and potassic primitive rocks. Magnesiochromite is the main spinel; it has been found enclosed in olivine cores. Olivine-spinel pairs indicate that the magmas from which they crystallized were in equilibrium with a strongly depleted mantle source. An origin from a common mantle source, in terms of a peridotitic component, is inferred for the different varieties of ultrapotassic to subalkaline primitive rocks. This source was characterized by different degrees of metasomatic enrichment arranged in a network of veins, possibly within the lithospheric upper mantle.
2007, Contributo in atti di convegno, ENG
Franchini, S.; Gentile, A.; Grimaudo, M.; Hung, C. A.; Impastato, S.; Sorbello, F.; Vassallo, G.; Vitabile, S.
Computer graphics applications require efficient tools to model geometric objects. The traditional approach based on compute-intensive matrix calculations is error-prone due to a lack of integration between geometric reasoning and matrix-based algorithms. Clifford algebra offers a solution to these issues since it permits specification of geometry at a coordinate-free level. The best way to exploit the symbolic computing power of geometric (Clifford) algebra is supporting its data types and operators directly in hardware. This paper outlines the architecture of S-CliffoSor (Sliced Clifford coprocesSor), a parallelizable embedded coprocessor that executes native Clifford algebra operations. S-CliffoSor is a sliced coprocessor that can be replicated for parallel execution of concurrent Clifford operations. A single slice has been designed, implemented and tested on the Celoxica Inc. RC1000 board. The experimental results show the potential to achieve a 3x speedup for Clifford sums and 4x speedup for Clifford products compared to against the analogous operations in the software library generator GAIGEN. © 2007 IEEE.
2007, Articolo in rivista, ENG
Spinola, Monica; Colombo, Francesca; Falvella, F. Stefania; Dragani, Tommaso A.
Isopentenyladenosine (i(6)A) is a product of isopentenyltransferases and, in mammals, occurs either bound to tRNA or as a free nucleoside. Sporadic reports have suggested an anticancer effect of i(6)A, mostly on leukemia cells. The present analysis of 9 human epithelial cancer cell lines derived from different types of malignant tissue revealed complete suppression of clonogenic activity in 8 of the lines after exposure to i(6)A at a concentration of 10 mu M. Mechanistic studies showed that i(6)A tumor suppressor activity is associated with inhibition of cell proliferation, a block in DNA synthesis and morphological changes. These results point to i(6)A and to its possible derivatives as a new potential class of wide-spectrum anticancer agents. (c) 2007 Wiley-Liss, Inc.
2007, Articolo in rivista, ENG
Cherchi, Annalisa; Gualdi, Silvio; Behera, Swadhin; Luo, Jing Jia; Masson, Sebastien; Yamagata, Toshio; Navarra, Antonio
The Indian summer monsoon (ISM) is one of the main components of the Asian summer monsoon. It is well known that one of the starting mechanisms of a summer monsoon is the thermal contrast between land and ocean and that sea surface temperature (SST) and moisture are crucial factors for its evolution and intensity. The Indian Ocean, therefore, may play a very important role in the generation and evolution of the ISM itself. A coupled general circulation model, implemented with a high-resolution atmospheric component, appears to be able to simulate the Indian summer monsoon in a realistic way. In particular, the features of the simulated ISM variability are similar to the observations. In this study, the relationships between the ISM and tropical Indian Ocean (TIO) SST anomalies are investigated, as well as the ability of the coupled model to capture those connections. The recent discovery of the Indian Ocean dipole mode (IODM) may suggest new perspectives in the relationship between ISM and TIO SST. A new statistical technique, the coupled manifold, is used to investigate the TIO SST variability and its relation with the tropical Pacific Ocean (TPO). The analysis shows that the SST variability in the TIO contains a significant portion that is independent from the TPO variability. The same technique is used to estimate the amount of Indian rainfall variability that can be explained by the tropical Indian Ocean SST. Indian Ocean SST anomalies are separated in a part remotely forced from the tropical Pacific Ocean variability and a part independent from that. The relationships between the two SSTA components and the Indian monsoon variability are then investigated in detail.
2007, Articolo in rivista, ENG
Solano, Emanuela; Castiglia, Riccardo; Corti, Marco
In this paper we describe a new Robertsonian (Rb) race of the house mouse from Vulcano (Aeolian archipelago) through the identification of the metacentric chromosomes. We analysed fifteen mice. All the specimens were found to have the same karyotype 2n = 26. This karyotype is characterized by Rb(1.2), Rb(3.9), Rb(4.13), Rb(5.14), Rb(8.12), Rb(10.16) and Rb(15.17). The differences between the race of Vulcano and the races in a neighbour island (Lipari) consist in the presence of Rb(10.16) and Rb(15.17) in the former and Rb(6.16) and Rb(10.15) in the latter. We discuss the possible hypotheses regarding the origin between these two races including the possible occurrence of a whole arm reciprocal translocation (WART) on the Vulcano island.
2007, Rapporto tecnico, ITA
Miozzi Massimo
Determinare l'andamento del flusso su una carena osservando i tracciati dei filetti di vernice su sdi essa
2007, Performance, ITA
Isabella Maria Zoppi
Conferenza musicata per la presentazione del cd Porta dei Canti. Raccontando Genova, allegato al volume Genova. Una porta del Mediterraneo, a cura di Luciano Gallinari, con Cristiano Angelini, Alessio Lega, Marco Spiccio e Isabella Maria Zoppi (Palazzo Tursi, Genova, 17 marzo 2007)
2007, Performance, ITA
Isabella Maria Zoppi
Conferenza musicata per la presentazione del cd Porta dei Canti. Raccontando Genova, allegato al volume Genova. Una porta del Mediterraneo, a cura di Luciano Gallinari, con Claudio Pozzani, Max Manfredi, Cristiano Angelini, Alessio Lega, Marco Spiccio e Isabella Maria Zoppi (Teatro della Corte, Genova, 9 marzo 2007).
2007, Rapporto tecnico, ITA
Rita Zaghi
Analisi dell'adeguamento del quadro giuridico dei Fondi Strutturali in un'ottica di rafforzamento della convergenza economica e sociale dei paesi UE
2007, Rapporto tecnico, ITA
Rita Zaghi
Analisi dell'applicazione normativa comunitaria sugli appalti
2007, Rapporto tecnico, ITA
Rita Zaghi
L'impatto delle direttive comunitarie nei settori dei lavori, forniture e servizi
2007, Software, ITA
Teodosio Lacava, Giovanni Calice, Irina Coviello, Nicola Pergola
Il sistema, sviluppato nell'ambito del Progetto: "Realizzazione di una piattaforma scientifico-tecnologica di osservazioni della Terra nel settore dei rischi ambientali", prevede: i) il subset spaziale sul bacino del Mediterraneo e la trasformazione in formato NetCDF dei dati Level 1B AVHRR e MODIS ricevuti direttamente dalla stazione di ricezione HRPT del CNR-IMAA; ii) il subset spaziale sul territorio della Regione Basilicata dei dati Level 1d AMSU ricevuti direttamente dalla stazione di ricezione HRPT del CNR-IMAA e la successiva elaborazione secondo i dettami della metodologia RST-SWVI; iii) il successivo trasferimento di tutti gli output nella Spatial Data Infrastructure della Regione Basilicata.