117,327 research outputs found
Prefazione
No full textLa funzione e le caratteristiche della ricerca filologica, con particolare riguardo all'Edizione Nazionale delle Opere di Antonio Fogazzaro e particolare riferimento alla cura del Mistero del Poet
Astuzie del pudore. Modi e forme della comunicazione obliqua nelle lettere di Montale, in La prosa di Eugenio Montale. Forme, generi, contesti, a cura di L. Bellomo e G. Morbiato, Padova University press, 2022, pp. 107-126.
No full textPresynaptic enzymatic neurotoxins
No full textBotulinum neurotoxins produced by anaerobic bacteria of the genus Clostridium are
the most toxic proteins known, with mouse LD50 values in the 1-5 ng/kg range, and
are solely responsible for the pathophysiology of botulism. These
metalloproteinases enter peripheral cholinergic nerve terminals and cleave
proteins of the neuroexocytosis apparatus, causing a persistent, but reversible,
inhibition of neurotransmitter release. They are used in the therapy of many
human syndromes caused by hyperactive nerve terminals. Snake presynaptic PLA2
neurotoxins block nerve terminals by binding to the nerve membrane and catalyzing
phospholipid hydrolysis with production of lysophospholipids and fatty acids.
These compounds change the membrane conformation, causing enhanced fusion of
synaptic vesicle via hemifusion intermediate with release of neurotransmitter
and, at the same time, inhibition of vesicle fission and recycling. It is
possible to envisage clinical applications of the lysophospholipid/fatty acid
mixture to inhibit hyperactive superficial nerve terminals
Franco Fortini: "Il comunismo in cammino" come "capacità di riconoscersi nei passati e nei venturi"
No full textIl mio saggio, dopo una prima parte finalizzata a fornire un quadro complessivo del percorso teorico-politico di Fortini, consisterà, nella seconda parte, più ampia, soprattutto nell’analisi approfondita di un breve testo sul comunismo, ora presente in "Extrema ratio. Note per un buon uso delle rovine" (1990), che mi pare condensare in modo icastico alcuni segni distintivi dell’articolazione fortiniana del comunismo, con la sua temporalità specifica. Anche se in Fortini spesso la dimensione del presente appare fortemente compressa, mi pare di poter rinvenire un approccio, seppur instabilmente, volto a interpretare il rapporto fra presente e futuro in termini più articolati, all’interno di un campo di battaglia sempre aperto, di un’antitesi mai risolta fino in fondo, e continuamente da verificare, fra un’utopia del futuro e un impegno politico nel presente
Different mechanisms of inhibition of nerve terminals by botulinum and snake presynaptic neurotoxins
No full textThe different mode of action on peripheral nerve terminals of the botulinum
neurotoxins and of the snake presynaptic phospholipase A2 neurotoxins is reviewed
here. These two groups of toxins are highly toxic because they are neurospecific
and at the same time are enzymes that can modify many substrate molecules before
being inactivated. The similarity of symptoms they cause in humans derives from
the fact that both botulinum neurotoxins (seven serotypes named A-G) and snake
presynaptic PLA2 neurotoxins block the nerve terminals and that peripheral
cholinergic terminals are major targets. Given this general similarity of targets
and clinical symptoms, the specific molecular and cellular mechanisms at the
basis of their action are very different. This difference appears evident from
the beginning of intoxication, i.e. neurotoxins binding to peripheral nerve
terminals and proceeds with the different site of actions and molecular targets
Analogs of a natural peptaibol exert anticancer activity in both cisplatin-and doxorubicin-resistant cells and in multicellular tumor spheroids
No full textPeptaibols, by disturbing the permeability of phospholipid membranes, can overcome anticancer drug resistance, but their natural hydrophobicity hampers their administration. By a green peptide synthesis protocol, we produced two water-soluble analogs of the peptaibol trichogin GA IV, termed K6-Lol and K6-NH2. To reduce production costs, we successfully explored the possibility of changing the naturally occurring 1,2-aminoalcohol leucinol to a C-terminal amide. Peptaibol activity was evaluated in ovarian cancer (OvCa) and Hodgkin lymphoma (HL) cell lines. Peptaibols exerted comparable cytotoxic effects in cancer cell lines that were sensitive—and had acquired resistance—to cisplatin and doxorubicin, as well as in the extrinsic-drug-resistant OvCa 3-dimensional spheroids. Peptaibols, rapidly taken up by tumor cells, deeply penetrated and killed OvCa-spheroids. They led to cell membrane permeabilization and phosphatidylserine exposure and were taken up faster by cancer cells than normal cells. They were resistant to proteolysis and maintained a stable helical structure in the presence of cancer cells. In conclusion, these promising results strongly point out the need for further preclinical evaluation of our peptaibols as new anticancer agents
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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