116 research outputs found
Registrazione dei potenziali tardivi ventricolari in pazienti con TV ma senza cardiopatia ischemica.
No full textAcute and chronic acidosis influence on antioxidant equipment and transport proteins of rat jejunal enterocyte
No full textAcidosis elicits the formation of oxidants and, in turn, ROS (reactive oxygen species)-induced intestinal diseases cause acidosis. This research investigated whether both acute and chronic acidosis influence the antioxidant enzymatic equipment of rat jejunocyte, including γ-GT activity, involved in GSH (glutathione) homoeostasis. Lipid peroxidation level and the expressions of (Na+,K+)-ATPase and GLUT2 were also investigated. The possible influence of acidosis on ROS action was tested. Isolated apical membranes, everted sac preparations and homogenates from acidotic rats were used. γ-GT activity is inhibited after incubation of isolated membranes at acidic pH, but using the whole intestinal tract this inhibition disappears, while SOD (superoxide dismutase) and GR (glutathione reductase) activities are enhanced. Also, in conditions of chronic acidosis, c-GT activity is unaffected, but no variations of antioxidant activities are apparent. (Na+,K+)-ATPase expression increases, while GLUT2 decreases in acidotic animals. Lipid peroxidation level is unaffected by acidosis. H2O2 inhibits γ-GT activity only in isolated membranes; in the whole tissue, it enhances CAT (catalase) and SOD activities and reduces GLUT2 expression. The pattern of responses to oxidant agents is unaffected by acidosis. Although jejunum seems quite resistant to acidosis, results, suggesting specific responses to this condition, may direct further research on antioxidant supplementation
"Ho scritto quello che ho visto". La poetica di Grossman e il problema delle verità.
No full text«HO SCRITTO QUELLO CHE HO VISTO».
La poetica di Grossman e il problema delle verità
La tesi intende presentare il percorso poetico e concettuale dello scrittore Vasilij Grossman (1905-1964) evidenziando i punti di contatto e i punti di rottura con il «paradigma sovietico» del suo tempo.
Attraverso un percorso che parte dal debutto ufficiale dello scrittore negli anni Trenta per arrivare alla scrittura della prima e della seconda parte della «dilogia di Stalingrado» (Za pravoe delo, 1952; Žizn’ i sud’ba, pubblicato postumo nel 1980), la tesi individua alcuni snodi fondamentali della produzione artistica grossmaniana che documentano una caratteristica specifica della sua attività artistico-letteraria: la tensione tra i confini specifici imposti alla letteratura sovietica nelle diverse fasi del suo sviluppo e le esigenze individuali di emancipazione intellettuale e artistica.
Il percorso è sviluppato accostando un’analisi letteraria dei motivi e delle tematiche di alcune opere a una serie di documenti d’archivio, alcuni dei quali inediti, che disegnano il difficile rapporto dello scrittore con le istituzioni ufficiali e l’influsso che esse hanno esercitato nell’elaborazione artistica di Grossman, ossia nel suo tentativo di definire uno specifico spazio mito-poietico personale.
Ad attraversare l’intero lavoro di ricerca è il problema specifico del rapporto tra il primo e il secondo Grossman, ovvero tra le opere che furono pubblicate in Unione Sovietica e quelle postume, proibite e censurate dal regime sovietico.
L’elaborazione della tesi, in tre capitoli, rende conto dello sviluppo della poetica di Grossman che si snoda tra due verità: da una parte la verità «esteriore» o «ufficiale», dall’altra quella «individuale». Obiettivo del lavoro è mostrare la specificità di Vasilij Grossman e l’evolversi della categoria della verità intesa come fondamento della sua opera. Il lavoro di tesi può essere perciò considerato come una critica delle immagini della verità nella poetica grossmaniana.«I WROTE WHAT I SAW».
Grossman’s poetics and the issue of truths
This thesis aims to explain the poetic and the conceptual path of Vasily Grossman (1905-1964), in particular focusing on meeting and breaking points with the «Soviet paradigm» of his times.
Along a path, which starts from the writer’s official debut in the early Thirties and concludes with the writing of the first and the second part of the «dilogy of Stalingrad» (Za pravoe delo, 1952; Žizn’ i sud’ba, published in 1980 after author’s death), the thesis highlights some of the most important turning points of Grossman’s artistic production. These points underline a specific characteristic of his literary activity: the tension between official Soviet literature borders throughout different stages of its development and Grossman’s individual needs of intellectual and artistic emancipation.
The thesis develops a literary analysis of topics and themes of some Grossman’s works in relation with several archive documents, some of which are not yet published. This path shows the strained relationship between the author and official institutions and their influence on Grossman’s artistic elaboration, i.e. on his attempt to define a specific personal mytho-poetic space.
The main issue, that runs under the entire research work, is the relationship between the first and the second Grossman, that is the relationship between the author’s works which were published in Soviet Union and the works which were censured and published after his death.
The thesis, composed of three parts, demonstrates that in Grossman’s poetics lie two truths: on the one hand, the «exterior» or «official» truth, and on the other hand the «individual» one. The aim of this thesis is to show the peculiarity of Vasily Grossman’s poetics and the progress of the category of truth that is considered as the roots of his work. Therefore, this thesis can be considered a critique of the figures of the truth in Grossman’s poetics
PKA regulation of bicarbonate and lactate movements across rat jejunal plasma membranes
No full textBackground/Aims: Evidence was previously given that the mechanisms involved in bicarbonate and lactate movements across rat jejunal enterocyte are modulated by PKC and Ca2+/CaM. Aim of this study was to investigate the possible role of PKA on bicarbonate and lactate transports. Methods: Enzymatic assays in isolated plasma membranes were performed. Moreover membrane vesicles, transiently opened and resealed, were treated with a phosphorylating solution (leading to PKA activation) and were used after that to perform uptake studies. Results: Enzymatic assays give evidence for the presence of PKA in plasma membranes from rat jejunum. Uptake experiments suggest that PKA stimulates the two systems that accomplish basolateral HCO3- efflux from the enterocyte, namely Cl-/ HCO3- exchanger and HCO3- conductance, without affecting HCO3- influx from the lumen mediated by Na+/H+ exchanger activity. Moreover basolateral H+/lactate symporter is stimulated by PKA, as well as the brush border isoform of Na+-glucose cotransporter SGLT1. Conclusion: PKA activation evokes individual responses that could be coordinated through cellular metabolism
ANTIOXIDANT EQUIPMENT OF JEJUNAL EPITHELIAL CELLS: RESPONSE TO ACUTE AND CHRONIC METABOLIC ACIDOSIS
No full textWe investigated whether acute and chronic acidosis affect the antioxidant enzymatic equipment of rat jejunum, including g-GT, involved in glutathione homeostasis. Lipid peroxidation level and expressions of (Na+, K+)-ATPase and GLUT2 were also tested, as well as the possibile influence of acidosis on ROS action. Isolated apical membranes, everted sac preparations and homogenates from acidotic rats were used.
g-GT activity is inhibited after incubation of isolated membranes at acidic pH; using the whole intestinal tract this inhibition disappears, while superoxide dismutase and glutathione reductase activities are enhanced,indicating that acidosis elicited an antioxidant defense. Also in metabolic acidosis g-GT activity is unaffected, but antioxidant activities keep constant: thus we can hypothesize thatafter 7 days of chronic acidosis the compensatory response is accomplished.(Na+, K+)-ATPase expression increases whilst GLUT2 level decreases in acidotic animals, suggesting a specific regulation of function. Lipid peroxidation level is unaffected by acidosis.
H2O2 inhibits g-GT activity only in isolated membranes; in the whole isolated tissue it enhances catalase and superoxide dismutase activities and reduces GLUT2 expression. The pattern of responses to various oxidant agents is unaffected by acidosis.
Although jejunum seems quite resistant to acidosis, results suggest specific responses to this condition and may direct further research on antioxidant supplementation
Protein kinase C regulation of rat jejunal transport systems: mechanisms involved in bicarbonate absorption
No full textWe examined whether PKC modulates the transport systems involved in bicarbonate movements across the plasma membranes of rat jejunum. Results of enzymatic assays give evidence that under basal conditions cPKC is present in both basolateral (BLM) and apical (BB) membranes of the enterocyte. In BLM the basal expression of the kinase is significantly lower than in BB; however treatment with Ca2+ and phorbol 12-myristate 13-acetate (PMA) causes a significant increase, thus suggesting an asymmetrical kinase translocation. To explore the effect of PKC activation on membrane-bound transport mechanisms, “in vitro” phosphorylated membrane vesicles were used to perform uptake studies. Results suggest that PKC activation exerts an inhibitory effect on basolateral Cl-/HCO3- antiport, whereas basolateral HCO3- conductive pathway seems to be stimulated and Cl- conductance unaffected. Apical, but not basolateral, Na+/H+ exchanger is inhibited by PKC activation. The specificity of the response to PKC was confirmed by using staurosporine or 4-a-PMA. The inhibition of both apical Na+/H+ and basolateral Cl-/HCO3- exchange activities suggests that the overall action of PKC determines a reduction of transepithelial bicarbonate transport
Studî dialettali veneti. — Max Goldstaub u. Richard Wendriner, Ein tosco-venezianischer Bestiarius, herausgegeben u. erläutert, 1892 ; Francesco Novati , La «Navigatio Sancti Brendani », in antico veneciano, edita ed illustrata, 1892 ; Leone Luzzatto, I dialetti moderni dette città di Veneria e Padova. Parte I , Analisi dei suoni, 1892
No full textParodi E.-G. Studî dialettali veneti. — Max Goldstaub u. Richard Wendriner, Ein tosco-venezianischer Bestiarius, herausgegeben u. erläutert, 1892 ; Francesco Novati , La «Navigatio Sancti Brendani », in antico veneciano, edita ed illustrata, 1892 ; Leone Luzzatto, I dialetti moderni dette città di Veneria e Padova. Parte I , Analisi dei suoni, 1892. In: Romania, tome 22 n°86, 1893. pp. 300-314
Effects of creatine in a rat intestinal model of ischemia/reperfusion injury
No full textCreatine belongs to a buffering system of cellular ATP level and shows direct antioxidant activity. Our aim was to investigate if creatine could improve enterocytes antioxidant response and limit the oxidant injury induced by anoxia and reoxygenation. etc..
Oxidative stress reduces transintestinal transports and (Na+, K+)-ATPase activity in rat jejunum
No full textBecause oxidative stress is a component of gastrointestinal injury, we investigated the effect of H(2)O(2) on transintestinal transport using isolated rat jejunum incubated in vitro. Millimolar concentrations of H(2)O(2) inhibited all the tested parameters without inducing any cytotoxic effect. Electrophysiological experiments indicated that H(2)O(2) decreases significantly both short circuit current and transepithelial electrical potential difference without affecting transepithelial resistance. The possibility that H(2)O(2) could influence (Na+, K+) -ATPase activity was explored using isolated basolateral membranes. Besides H(2)O(2), free radicals (O(2)(*-), HO*) were generated using different iron-dependent and independent systems; (Na+, K+) -ATPase activity was inhibited after membrane exposure to all ROS tested. The inhibition was prevented by allopurinol, superoxide dismutase or desferrioxamine. Western blot analysis showed a decreased expression of the alpha(1)-subunit of (Na+, K+) -ATPase. We conclude that H(2)O(2) may be a modulator of jejunal ion and water transport by multiple mechanisms, among which a significant inhibition of the basolateral (Na+, K+) -ATPase
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