102,423 research outputs found
Nanoceria protect retinal pigment epithelium in the light damaged retina
No full textPurpose : Dry age-related macular degeneration (AMD) is the most common form of AMD, characterized by retinal pigment epithelium (RPE) dysfunction and death, associated to lipofuscin accumulation, photoreceptors death, autophagy alterations and vision loss. Despite its frequency, only palliative therapies are available. In order to search for improvements we investigated the development of the dry AMD in the light damaged (LD) model and tested the protective effects of cerium oxide nanoparticles (nanoceria).
Methods : The dry features of AMD were investigated on Sprague Dawley albino rats exposed to bright light (1000 lux) for 3h, 6h, 9h, 12h, 24h and for 24h followed by 3 and 7 days of recovery, then compared to the healthy controls. The treatment was performed by nanoceria intravitreal injection (2 μl [1mM]) in both eyes 3 days before light exposure (for 24h). After 7 days from injury treated and untreated animals were compared. Oxidative stress was evaluated by acrolein fluorescence intensity on immunolabeled retinal cryosections and RPE was pointed out by anti-RPE65 immunofluorescence. Lipofuscin quantitation was performed by ImageJ software on retinal whole mounts images acquired by confocal microscopy. Autophagy was analysed by LC3B-II western blot.
Results : The RPE was disrupted in the dorsal retina of LD rats starting 3 days after injury. LCB3-II was significantly increased after 24h of light exposure (p<0,05) and remained up-regulated after 7 days of recovery (p<0,05). We also observed lipofuscin accumulation over time and increased oxidative stress already detectable after 7 days of recovery. By nanoceria treatment oxidative stress was significantly reduced in the outer nuclear layer (p<0,01) and in the RPE (p<0,05) of the treated group. Accordingly the blood-retinal barrier was intact since the RPE was not affected and lipofuscin was significantly reduced in terms of number of granules (p<0,001) and percentage of occupied area (p<0,001). LCB3-II was down-regulated in the nanoceria-treated animals compared to the untreated ones (p<0,001).
Conclusions : Our study demonstrates that cerium oxide nanoparticles protect the RPE and limit the dry features of AMD in the light-damaged model. On this basis we propose nanoceria as a new potential therapeutic agent for the dry form of AMD
Simulazione numerica del flusso oscillante su una parete scabra
No full textNell’articolo è affrontato lo studio del flusso oscillante su una parete coperta da una scabrezza
regolare. La scabrezza considerata è costituita da semisfere disposte su una parete piana secondo una
matrice esagonale. Le equazioni che reggono il moto del fluido sono state risolte numericamente su
una griglia cartesiana. Le condizioni al contorno sulla parete sono state imposte utilizzando la tecnica
dei contorni immersi (Fadlun et al., 2000). Il metodo numerico è stato validato riproducendo i risultati
sperimentali di Keiller & Sleath, (1976). E’ analizzato l’andamento temporale delle strutture vorticose
e delle forze indotte sulla parete dalle oscillazioni del fluido. Il lavoro numerico condotto contribuisce
a chiarire alcuni aspetti dei lavori sperimentali presenti in letteratura (Keiller & Sleath, 1976; Sleath,
1987; Jensen et al., 1989) e risulta essere un potente strumento di indagine nello studio di questo tipo
di flusso
DNS del flusso oscillante su una parete scabra
No full textNel presente lavoro si affronta lo studio del campo di moto di un fluido che oscilla
al di sopra di una parete scabra. Sono state effettuate delle simulazioni numeriche dirette delle
equazioni di Navier-Stokes con l’ausilio della tecnica dei “contorni immersi” (Fadlun et al., 2001)
per imporre le condizioni al contorno sulla parete. Il metodo numerico è stato ampiamente testato
e sono stati effettuati confronti con risultati sperimentali. I risultati delle simulazioni numeriche
effettuate hanno consentito un’indagine approfondita del campo di moto e in particolare della
dinamica delle strutture vorticose coerenti. E’ stata inoltre analizzata la distribuzione spaziale e
temporale delle tensioni scambiate tra il fluido e la parete. Mantenendo fissa la geometria della
parete sono state effettuate simulazioni per diversi valori del numero di Reynolds.In this paper the flow field generated by a longitudinal pressure gradient which
oscillates periodically above a rough wall has been studied. Direct numerical simulations of the
Navier-Stokes equation have been performed for different values of the Reynolds number, keeping
the geometry of the wall fixed. In order to force the boundary condition on the rough wall, the
“immersed boundaries” tecnique (Fadlun et al., 2001) has been adopted. The numerical method
has been tested and the results have been compared with experimental data. The obtained results
concern the flow field and the coherent vortex structures. Moreover the spatial and the temporal
distribution of the stresses on the bed is described
Up-regulation of pro-angiogenic pathways and induction of neovascularization by an acute retinal light damage.
No full textThe light damage (LD) model was mainly used to study some of the main aspects of age related macular degeneration (AMD), such as oxidative stress and photoreceptor death. Several protocols of light-induced retinal degeneration exist. Acute light damage is characterized by a brief exposure (24 hours) to high intensity light (1000 lux) and leads to focal degeneration of the retina which progresses over time. To date there are not experimental data that relate this model to neovascular events. Therefore, the purpose of this study was to characterize the retina after an acute light damage to assess whether the vascularization was affected. Functional, molecular and morphological investigations were carried out. The electroretinographic response was assessed at all recovery times (7, 60, 120 days after LD). Starting from 7 days after light damage there was a significant decrease in the functional response, which remained low up to 120 days of recovery. At 7 days after light exposure, neo-vessels invaded the photoreceptor layer and retinal neovascularization occurred. Remarkably, neoangiogenesis was associated to the up-regulation of VEGF, bFGF and their respective receptors (VEGFR2 and FGFR1) with the progression of degeneration. These important results indicate that a brief exposure to bright light induces the up-regulation of pro-angiogenic pathways with subsequent neovascularization
Ricostruzione della parete toracica per neoplasia del manubrio sternale
No full textIl trattamento demolitivo dei tumori della parete toracica e la successiva ricostruzione con la conservazione di una soddisfacente meccanica respiratoria è un recente traguardo della chirurgia toracica. Nel 1858 Parham descrisse per primo l'asportazione di una porzione di parete toracica per neoplasia. l'ostacolo principale era allora costituito dall'insorgenza di pneumotorace all'apertura delle pleure. L'introduzione nella pratica clinica della ventilazione a pressione positiva consentì di ovviare a questo inconveniente. L'interesse dei chirurghi si diresse allora alla messa a punto di tecniche che consentissero la ricostruzione della parete toracica conservando una soddisfacente meccanica respiratoria. A Questo scopo fu proposto l'utilizzo della fascia lata, di segmenti di coste, di flaps cutanei, di peduncoli muscolari, del grande omento ed infine, più recentemente, di protesi artificiali. proprio la disponibilità di protesi artificiali di facile utilizzo, ad alta resistenza, e ben tollerate dall'ospite ha reso la ricostruzione dei difetti della parete toracica più agevole e quindi ha esteso le indicazioni alla demolizione anche in casi in cui siano necessarie ampie resezioni.The case of a voluminous neoplasia originating at the manubrium sterni is described. Given the rapid growth of the mass and its dimensions, the mass was removed surgically together with the manubrium sterni and the sternal extremity of the clavicle and of the first two ribs. The defect in the anterior wall of the thorax was filled by a net of prolene partially covered with the mobilised pectoral muscles. Functional and aesthetic results were very good. Assisted respiration was not necessary in the immediate postoperative period and the net remained stable and firmly in place during respiration. One month after the operation, respiratory function tests were on a par with those done prior to the operation. The positioning of prolene nets for the reconstruction of the thoracic wall is an extremely effective technique which makes it possible to preserve satisfactory respiratory mechanics even after the removal of extensive portions of the thoracic wall
Chirurgia al limite nel cancro broncogeno. Tumori polmonari invadenti parete toracica e diaframma (escluso l’apice).
No full textLo studio riguarda il cancro del polmone invadente la parete toracic
Su due casi di ernia della parete toracica.
No full textE' descitta la tecnica chirurgica per le ernie della parete toracic
Somministrazione topica elettrostimolata di mitomycina C su parete di vescica umana. Studio in vitro
No full textSomministrazione topica elettrostimolata di mitomycina C su parete di vescica umana. Studio in vitro
Evaluating flow regime alterations due to point sources in intermittent rivers: A modelling approach
No full textHydrological regime alterations may strongly influence river morphology, water quality, and river ecosystem. The present paper aimed to define an integrated modelling framework for analysing the hydrological regime alterations induced by point sources (PSs) discharges in data-limited regions through two case studies: the Canale d'Aiedda (Italy) and Nil wadi (Algeria). Long time series of daily streamflow in un-impacted and impacted (PSs discharges) conditions were generated by applying the Soil and Water Assessment Tool model and the hydrological regime was characterised by using several hydrological indicators. Flow regime alterations due to PSs were assessed with the range of variability approach. Results showed that the PSs induced alterations of some flow regime components (magnitude, duration, and timing). Hydrological regime classification of the river reaches receiving wastewaters from PSs shifted from intermittent to perennial. All the components of the low flow (1-, 3-, 7-, 30-, and 90-day minimum flow, zero-days) and the monthly flow recorded in summer were severely altered. Minor hydrological alterations were assessed for high flow components (1-, 3-, 7-, 30-, and 90-day maximum flow) and mean monthly flow in the wet period. The tuning of minimum flow was found to shift later in the year. This study may support river ecologists in the ecological status evaluation
Valutazione di materiali biocompatibili nella riparazione di difetti della parete addominale
No full textVALTUTAZIONE DELL'UTILIZZO DI MATERIALI BIOCOMPATIBILI NELLA CORREZIONE DEI DIFETTI DELLA PARETE ADDOMINALE: STUDIO SPERIMENTAL
- …
