203 research outputs found

    Prevalenza della sclerosi multipla nell'isola d'Elba

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    OBIETTIVI: Calcolare la prevalenza della Sclerosi Multipla (SM) nell’isola d’Elba dal momento che non ci sono dati disponibili in letteratura. METODI: L'isola d'Elba è l’isola più grande dell'Arcipelago Toscano. Al giorno di prevalenza, ovvero il 31/12/2010, la popolazione residente nell’isola era pari a 31.943 ab. I casi di SM sono stati identificati consultando le cartelle cliniche dell’ospedale e dell’ambulatorio neurologico di riferimento dell’isola. Sono stati arruolati nello studio tutti i pazienti con diagnosi di SM secondo i criteri di McDonald, residenti nell’isola al giorno di prevalenza. Sono stati calcolati i tassi di prevalenza grezzi e specifici (sesso e età) e il tasso standardizzato rispetto alla popolazione italiana del 2001. Gli intervalli di confidenza al 95% dei tassi di prevalenza sono stati calcolati assumendo una distribuzione di Poisson. RISULTATI: Al giorno di prevalenza erano residenti nell’isola 42 soggetti con SM. Di questi il 40,5% era nato fuori dall’isola e 4 pazienti avevano origine sarda. Il rapporto F:M è risultato pari a 2,8 e l’età media dei soggetti era di 49,8±12,6 anni. Per quanto riguarda le forme di malattia, il 16,7% dei pazienti aveva una forma CIS, il 61,9% una RR, il 16,7% una SP e il 4,8% una PP. Il grado di disabilità (EDSS) è risultato correlato (trend crescente) con la forma di malattia: EDSS pari a 1,5 per le forme CIS, 2,0 per le RR e 6,0 per le SP e PP. La durata di malattia, in media, era di 15,0±9,8 anni, con un range tra 0 e 37 anni. Il tasso di prevalenza grezzo è risultato pari a 131,5 (IC 95%: 99,8-177,7) per 100.000 (maschi 70,7; femmine 189,2 per 100.000). Il tasso di prevalenza standardizzato è risultato pari a 131,5 (IC 95%: 91,8-171,2) per 100.000. Il tasso di prevalenza sesso età specifico mostra un picco, per entrambi i sessi, nella classe di età tra 45-54 anni, mentre non ci sono casi prima dei 15 anni. Analizzando il periodo di latenza (ovvero la lunghezza in anni tra esordio dei sintomi e diagnosi di malattia) si osserva un trend negativo, statisticamente significativo, rispetto l’anno di esordio: infatti per i pazienti con esordio più recente, il periodo di latenza è diminuito rispetto a quello dei pazienti con esordio più remoto. CONCLUSIONI: Essendo il primo studio effettuato nell’isola, non è possibile fare confronti con dati precedenti. Il valore di prevalenza osservato dovrebbe essere comunque in linea con l’attuale prevalenza dell’Italia continentale e comunque inferiore a quella stimata in Sardegna (Pugliatti, 2009)

    Reconfigurable chaos in electro-optomechanical system with negative Duffing resonators

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    Generating various laser sources is important in the communication systems. We propose an approach that uses a mechanical resonator coupled with the optical fibre system to produce periodic and chaotic optical signals. The resonator is structured in such a way that the nonlinear oscillation occurs conveniently. The mechanical apparatus in the configuration is the well known resonating system featured by the negative stiffness. The mechanical resonance is converted to reflected optical signal with the same dynamic properties as the mechanical oscillation, subsequently interacting with the optical signal within the optical fibre. The optical radiative force on the mechanical structure is also considered in the analysis. The coupled electro-optomechanical system has been analysed, and results show that the mechanical resonator has the capability to control the dynamics of the optical signal precisely. The system will have potential applications in tunable laser sources

    Self-consistent Green's function method for nuclei and nuclear matter

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    Recent results obtained by applying the method of self-consistent Green's functions to nuclei and nuclear matter are reviewed. Particular attention is given to the description of experimental data obtained from the (e,e'p) and (e,e'2N) reactions that determine one and two-nucleon removal probabilities in nuclei since the corresponding amplitudes are directly related to the imaginary parts of the single-particle and two-particle propagators. For this reason and the fact that these amplitudes can now be calculated with the inclusion of all the relevant physical processes, it is useful to explore the efficacy of the method of self-consistent Green's functions in describing these experimental data. Results for both finite nuclei and nuclear matter are discussed with particular emphasis on clarifying the role of short-range correlations in determining various experimental quantities. The important role of long-range correlations in determining the structure of low-energy correlations is also documented. For a complete understanding of nuclear phenomena it is therefore essential to include both types of physical correlations. We demonstrate that recent experimental results for these reactions combined with the reported theoretical calculations yield a very clear understanding of the properties of {\em all} protons in the nucleus. We propose that this knowledge of the properties of constituent fermions in a correlated many-body system is a unique feature of nuclear physics.Comment: 110 pages, accepted for publication on Prog. Part. Nucl. Phy

    Design concepts for the Cherenkov Telescope Array CTA: an advanced facility for ground-based high-energy gamma-ray astronomy

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    Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA

    SDF1 in the dorsal corticospinal tract promotes CXCR4+ cell migration after spinal cord injury

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    <p>Abstract</p> <p>Background</p> <p>Stromal cell-derived factor-1 (SDF1) and its major signaling receptor, CXCR4, were initially described in the immune system; however, they are also expressed in the nervous system, including the spinal cord. After spinal cord injury, the blood brain barrier is compromised, opening the way for chemokine signaling between these two systems. These experiments clarified prior contradictory findings on normal expression of SDF1 and CXCR4 as well as examined the resulting spinal cord responses resulting from this signaling.</p> <p>Methods</p> <p>These experiments examined the expression and function of SDF1 and CXCR4 in the normal and injured adult mouse spinal cord primarily using CXCR4-EGFP and SDF1-EGFP transgenic reporter mice.</p> <p>Results</p> <p>In the uninjured spinal cord, SDF1 was expressed in the dorsal corticospinal tract (dCST) as well as the meninges, whereas CXCR4 was found only in ependymal cells surrounding the central canal. After spinal cord injury (SCI), the pattern of SDF1 expression did not change rostral to the lesion but it disappeared from the degenerating dCST caudally. By contrast, CXCR4 expression changed dramatically after SCI. In addition to the CXCR4+ cells in the ependymal layer, numerous CXCR4+ cells appeared in the peripheral white matter and in the dorsal white matter localized between the dorsal corticospinal tract and the gray matter rostral to the lesion site. The non-ependymal CXCR4+ cells were found to be NG2+ and CD11b+ macrophages that presumably infiltrated through the broken blood-brain barrier. One population of macrophages appeared to be migrating towards the dCST that contains SDF1 rostral to the injury but not towards the caudal dCST in which SDF1 is no longer present. A second population of the CXCR4+ macrophages was present near the SDF1-expressing meningeal cells.</p> <p>Conclusions</p> <p>These observations suggest that attraction of CXCR4+ macrophages is part of a programmed response to injury and that modulation of the SDF1 signaling system may be important for regulating the inflammatory response after SCI.</p

    Total and corrected antioxidant capacity in hemodialyzed patients

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    BACKGROUND: Oxidative stress may play a critical role in the vascular disease of end stage renal failure and hemodialysis patients. Studies, analyzing either discrete analytes and antioxidant substances, or the integrated total antioxidant activity of human plasma during hemodialysis, give contradictory results. METHODS: Recently, we have introduced a new automated method for the determination of Total Antioxidant Capacity (TAC) of human plasma. We have serially measured TAC and corrected TAC (cTAC: after subtraction of the interactions due to endogenous uric acid, bilirubin and albumin) in 10 patients before the onset of the dialysis session, 10 min, 30 min, 1 h, 2 h and 3 h into the procedure and after completion of the session. RESULTS: Our results indicate that TAC decreases, reaching minimum levels at 2 h. However, corrected TAC increases with t(1/2 )of about 30 min. We then repeated the measurements in 65 patients undergoing dialysis with different filters (36 patients with ethylene vinyl alcohol copolymer resin filter -Eval-, 23 patients with two polysulfone filters -10 with F6 and 13 with PSN140-, and 6 patients with hemophan filters). Three specimens were collected (0, 30, 240 min). The results of this second group confirm our initial results, while no significant difference was observed using either filter. CONCLUSIONS: Our results are discussed under the point of view of possible mechanisms of modification of endogenous antioxidants, and the interaction of lipid- and water-soluble antioxidants

    Interactions Between Estrogen- and Ah-Receptor Signalling Pathways in Primary Culture of Salmon Hepatocytes Exposed to Nonylphenol and 3,3',4,4'-Tetrachlorobiphenyl (Congener 77)

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    BACKGROUND: The estrogenic and xenobiotic biotransformation gene expressions are receptor-mediated processes that are ligand structure-dependent interactions with estrogen-receptor (ER) and aryl hydrocarbon receptor (AhR), probably involving all subtypes and other co-factors. The anti-estrogenic activities of AhR agonists have been reported. In teleost fish, exposure to AhR agonists has been associated with reduced Vtg synthesis or impaired gonadal development in both in vivo- and in vitro studies. Inhibitory AhR and ER cross-talk have also been demonstrated in breast cancer cells, rodent uterus and mammary tumors. Previous studies have shown that AhR-agonists potentiate xenoestrogen-induced responses in fish in vivo system. Recently, several studies have shown that AhR-agonists directly activate ERα and induce estrogenic responses in mammalian in vitro systems. In this study, two separate experiments were performed to study the molecular interactions between ER and AhR signalling pathways using different concentration of PCB-77 (an AhR-agonist) and time factor, respectively. Firstly, primary Atlantic salmon hepatocytes were exposed to nonylphenol (NP: 5 μM – an ER agonist) singly or in combination with 0.001, 0.01 and 1 μM PCB-77 and sampled at 48 h post-exposure. Secondly, hepatocytes were exposed to NP (5 μM) or PCB-77 (1 μM) singly or in combination for 12, 24, 48 and 72 h. Samples were analyzed using a validated real-time PCR for genes in the ER pathway or known to be NP-responsive and AhR pathway or known to be PCB-77 responsive. RESULTS: Our data showed a reciprocal inhibitory interaction between NP and PCB-77. PCB-77 produced anti-NP-mediated effect by decreasing the mRNA expression of ER-responsive genes. NP produced anti-AhR mediated effect or as inhibitor of AhRα, AhRR, ARNT, CYP1A1 and UDPGT expression. A novel aspect of the present study is that low (0.001 μM) and medium (0.01 μM) PCB-77 concentrations increased ERα mRNA expression above control and NP exposed levels, and at 12 h post-exposure, PCB-77 exposure alone produced significant elevation of ERα, ERβ and Zr-protein expressions above control levels. CONCLUSION: The findings in the present study demonstrate a complex mode of ER-AhR interactions that were dependent on time of exposure and concentration of individual chemicals (NP and PCB-77). This complex mode of interaction is further supported by the effect of PCB-77 on ERα and ERβ (shown as increase in transcription) with no concurrent activation of Vtg (but Zr-protein) response. These complex interactions between two different classes of ligand-activated receptors provide novel mechanistic insights on signalling pathways. Therefore, the degree of simultaneous interactions between the ER and AhR gene transcripts demonstrated in this study supports the concept of cross-talk between these signalling pathways

    CXCR7 Protein Expression in Human Adult Brain and Differentiated Neurons

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    Background: CXCR7 and CXCR4 are receptors for the chemokine CXCL12, which is involved in essential functions of the immune and nervous systems. Although CXCR7 transcripts are widely expressed throughout the central nervous system, little is known about its protein distribution and function in the adult brain. To evaluate its potential involvement in CXCL12/CXCR4 signaling in differentiated neurons, we studied CXCR7 protein expression in human brain and cultured neurons. Methodology/Principal Findings: Immunohistochemistry and RT-PCR analyses of cortex and hippocampus from control and HIV-positive subjects provided the first evidence of CXCR7 protein expression in human adult neurons, under normal and pathological conditions. Furthermore, confocal microscopy and binding assays in cultured neurons show that CXCR7 protein is mainly located into cytoplasm, while little to no protein expression is found on neuronal plasma membrane. Interestingly, specific CXCR7 ligands that inhibit CXCL12 binding to CXCR7 do not alter CXCR4-activated survival signaling (pERK/pAkt) in rat cortical neurons. Neuronal CXCR7 co-localizes to some extent with the endoplasmic reticulum marker ERp29, but not with early/late endosome markers. Additionally, large areas of overlap are detected in the intracellular pattern of CXCR7 and CXCR4 expression. Conclusions/Significance: Overall, these results implicate CXCR4 as the main CXCL12 signaling receptor on the surface o
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