4,044 research outputs found
Perché dialogando si impara? Spunti di riflessione tra antropologia e impliciti della formazione
No full textA partire dal riconoscimento della funzione primaria del "dialogo" nelle pratiche educative e riflessive il saggio ne esplora i fondamenti antropologici, mettendo in rilievo l'importanza della modellizzazione teorica - esplicita o implicita - che viene di volta in volta impiegata come sfondo per la comprensione delle dinamiche del pensiero e della decisione. Vengono in particolare analizzati i modelli antropologico-psicologici di Platone e di Freud
Histamine H3 receptors and the gastric mucosa: a link between protection and epithelial proliferation?
No full textThe role of histamine H3 receptors in the control of gastric functions is considered. The selective agonist of histamine H3 receptors, (R)-α-methylhistamine, reduces gastric damage exerted by mechanistically distinct noxious stimuli in the rat. Its effect is reversed by H3-receptor selective antagonists, ciproxifan and clobenpropit, while prevention of damage is similarly achieved with FUB 407, a reference compound for a novel class of histamine H3-receptor agonists structurally not related to histamine. It is concluded that H3 receptors are involved in the maintenance of gastric muscosal integrity. H3 receptors appear to have a minor role in the control of acid secretion, while they effectively enhance synthesis and secretion of mucus as well as increase the number of both surface mucous cells and mucous neck cells. H3 receptors ligands promptly increase the rate of proliferation in the gastric mucosa, their target being stem cells located in the isthmal region. They also influence the process of differentiation, by promoting the expansion of the lineage of surface mucous cells. Prevention of acute damage and regulation of cell cycle of gastric epithelial cells can be viewed as functionally linked effects, influenced by histamine H3 receptors
Famotidine Prevent Deep Histologic Lesion Induced by 0.6N HCl in Rat Gastric Mucosa : Role of Parietal Cells
No full textThe assessment of the protective actions of H-2-receptor antagonists against gastric mucosal Lesions by necrotizing agents relies on the gross observation of the gastric mucosa only. We examined the activity of famotidine against 0.6 N HCl-induced damage and the role of parietal cells by light and transmission electron microscopy. Rats received famotidine 0.3-10 mg/kg intragastrically. Sixty minutes later 0.6 N HCl (1 ml/rat) was given and after an additional 30 min the stomachs were removed. Macroscopically visible lesions were measured. Histologic lesions were scored on the basis of the depth. The ultrastructure of parietal cells in the isthmus-neck region was examined. Pretreatment with famotidine resulted in a slight increase of macroscopically visible gastric lesions in response to HCl. While the extent of total histologic damage was not modified, the antisecretory dose significantly reduced only lesions deep within the mucosa. Famotidine alone determined the dose-dependent occurrence of a distinct parietal cell morphological state, suggestive of inhibition of the secretory system. A causal link between the protective effect on the region where parietal cells are located, the percentage of cells shifting to the inhibited morphological state, and the inhibitory effect on acid secretion is proposed
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Epithelial cell proliferation is promoted by the histamine H3 receptor agonist (R)-alpha-methylhistamine throughout the rat gastrointestinal tract
No full textThe temporal effect of (R)-alpha-methylhistamine on epithelial cell proliferation throughout the rat gastrointestinal tract was investigated. (R)-alpha-methylhistamine was administered at 100 mg/kg orally and the rats were sacrificed 1, 24, 48, 72 and 144 h later. All the animals received 5-bromo-2'-deoxyuridine, (BrdU), 200 mg/kg i.p., 2 h before sacrifice. Gastrointestinal tissue was processed for histology and immunohistochemistry. (R)-alpha-methylhistamine caused a progressive increase in mucosal thickness of gastric fundus, distal small intestine and distal colon. Statistically significant differences from control values were found between 48 and 72 h after (R)-alpha-methylhistamine. (R)-alpha-methylhistamine significantly increased the number of BrdU-positive cells in the gastric fundus and antrum, intermediate and distal small intestine and distal colon. Peak effects were observed between 1 and 24 h after (R)-alpha-methylhistamine administration. Proliferating cell number and mucosal thickness were comparable to those of control rats at 144 h. (R)-alpha-methylhistamine exerts a long lasting growth-promoting effect on the stomach, distal small intestine and distal colon. Present data support a role of histamine H(3) receptors in the normal regulation of cell cycle in epithelial tissue
Ligands for histamine H3 receptors modulate cell proliferation and migration in rat oxyntic mucosa
No full text1 (R)-alpha-methylhistamine, a selective agonist of histamine H-3 receptors, promotes mucus secretion and increases the number and volume of mucus-secreting cells. The hypothesis that the increased number of mucous cells could reside in an alteration of homeostasis in the gastric epithelium was investigated.
2 (R)-alpha-methylhistamine was administered to rats 1 h (10-100 mg kg(-1) by intragastric and by intraperitoneal route) and 24 h (100 mg kg(-1) by intragastric route) prior to killing. The (S)-isomer of a-methylhistamine (55.4 mg kg(-1)), 100 times less potent than the (R)-isomer at H3 receptors, and the H-3-receptor agonist FUB 407 (9.14-91.35 mg kg(-1)) were intragrastically administered 1 h prior killing. The HI-receptor antagonist mepyramine (30 mg kg(-1)), the H-2-receptor antagonist famotidine (3 mg kg(-1)), and the H-3-receptor antagonists ciproxifan (3 mg kg(-1)) and clobenpropit (30 mg kg(-1)) were intragastrically administered 30 min before (R)-alpha-methylhistamine. Gastric tissue was processed for histology and immunohistochemistry.
3 Within 1 h, (R)-alpha-methylhistamine and FUB 407 dose-dependently increased the number of BrdU-positive cells and of apoptotic cells. (S)-alpha-methylhistamine failed to modify proliferation and apoptosis. The increase in proliferation by (R)-alpha-methylhistamine was reversed by ciproxifan and clobenpropit, but not by mepyramine and famotidine.
4 (R)-alpha-methylhistamine accelerated the differentiation towards pit cells and their outward migration 24 h after its administration. These effects were counteracted by ciproxifan. The apoptosis rate was unaffected at 24 h.
5 These findings reveal a primary role of histamine H-3-receptor ligands in modulating cell proliferation and migration in rat fundic mucosa
Le grandi battaglie della storia. Maratona (con introduzione di G. Rivieccio e postfazione di A. Santangelo)
No full textNella seconda metà del VI secolo a.C., l’impero persiano aveva raggiunto la sua massima estensione, arrivando fino all’Egeo orientale. Tra le popolazioni sottomesse c’erano anche le città dei Greci d’Asia Minore, governate da tiranni che agivano d’intesa con i Persiani. Nel 499, le città della Ionia si ribellarono ai Persiani, ricevendo sostegno anche dagli Ateniesi. Il sovrano persiano Dario I organizzò una spedizione punitiva contro la Grecia portando le sue truppe alle porte di Atene. Agli occhi degli Antichi, era evidente che in gioco ci fosse non solo la distruzione della città, ma l’occupazione di tutta la Grecia.
I Persiani scelsero la pianura di Maratona, a soli 40 chilometri da Atene, e sbarcarono con una flotta imponente, e un esercito di fanti, arcieri e cavalieri. Gli Ateniesi, con l’aiuto dei Plateesi, accorsero guidati da Milziade e decisero di attaccare. La tradizione antica insiste sull'inferiorità numerica degli Ateniesi che potevano contare solo sull'esercito oplitico. Stravolgendo le classiche tattiche di guerra dell’epoca, gli Ateniesi attaccarono in massa, correndo, cogliendo di sorpresa l’esercito persiano che si diede alla fuga. Le truppe ateniesi riuscirono così a respingere l'esercito persiano, che fece ritorno in Asia.
Questa vittoria inaspettata rappresentò per gli Ateniesi un evento paradigmatico, un episodio cui ispirarsi, anche in epoche successive, per ritrovare forza, coraggio e spirito di coesione
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