2,442 research outputs found
Un popolo di nani
No full textL’autore analizza compiutamente per la prima volta il pregevole ciclo di Nani lapidei collocati sul muro di cinta della villa Valmarana di Vicenza, che, proprio dalla loro presenza qualificante, ha tratto il nome di villa Valmarana “ai Nani”. Sgombrando il campo da precedenti attribuzioni, viene proposta la paternità di Giacomo Cassetti, erede del più importante scultore vicentino tra Sei eSettecento, quell’Orazio Marinali cui si deve l’introduzione in Veneto di questo particolare genere di scultura da giardino, che gode di larghissima diffusione in epoca barocca. L’occasione offre il destro per allargare la riflessione ad alcune caratteristiche ricorrenti: la forma seriale, la disposizione dei Nani uno di fianco all’altro, la predilezione per i costumi contemporanei, o tutt’al più il ricorso a fogge seicentesche. Il legame con la contemporaneità da un lato, la connotazione comico-grottesca dall’altro aiutano a comprendere il ruolo di queste statue all’interno del giardino veneto, dove compaiono sempre accanto a statue di soggetto mitologico: il loro significato, forse, secondo il principio del “contrapposto” di matrice barocca, risiede proprio nella dialettica tra i due gruppi
Respiratory Motoneurons and Pathological Conditions: lessons from hypoglossal motoneurons challenged by excitotoxic or oxidative stress.
No full textCina perduta : nelle fotografie di Leone Nani
No full textUn eccezionale reportage fotografico, realizzato da padre Leone Nani. E' quanto ci restituiscono queste immagini inedite, che riportano alla luce la memoria delle persone, dei luoghi, delle tradizioni e della cultura di un Impero scompars
Riluzole is a potent drug to protect neonatal rat hypoglossal motoneurons in vitro from excitotoxicity due to glutamate uptake block
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NanI Sialidase Contributes to the Growth and Adherence of Clostridium perfringens Type F Strain F4969 in the Presence of Adherent Mucus
No full textClostridium perfringens type F strains causing nonfoodborne human gastrointestinal diseases (NFD) typically produce NanI sialidase as their major secreted sialidase. Type F NFDs can persist for several weeks, indicating their pathogenesis involves intestinal colonization, including vegetative cell growth and adherence, with subsequent sporulation that fosters enterotoxin production and release. We previously reported that NanI contributes to type F NFD strain adherence and growth using Caco-2 cells. However, Caco-2 cells make minimal amounts of mucus, which is significant because the intestines are coated with adherent mucus. Therefore, it was important to assess if NanI contributes to the growth and adherence of type F NFD strains in the presence of adherent mucus. Consequently, the current study first demonstrated greater growth of nanI-carrying versus non-nanI-carrying type F strains in the presence of HT29-MTX-E12 cells, which produce an adherent mucus layer, versus their parental HT29 cells, which make minimal mucus. Demonstrating the specific importance of NanI for this effect, type F NFD strain F4969 or a complementing strain grew and adhered better than an isogenic nanI null mutant in the presence of HT29-MTX-E12 cells versus HT29 cells. Those effects involved mucus production by HT29-MTX-E12 cells since mucus reduction using N-acetyl cysteine reduced F4969 growth and adherence. Consistent with those in vitro results, NanI contributed to growth of F4969 in the mouse small intestine. By demonstrating a growth and adherence role for NanI in the presence of adherent mucus, these results further support NanI as a potential virulence factor during type F NFDs
Effetto di sostanze in diluizioni omeopatiche e di campi elettromagnetici deboli in modelli vegetali
No full textL’efficacia dell’omeopatia è tuttora oggetto di acceso dibattito (1-3) e, nonostante le numerose ipotesi formulate (4-9), il suo meccanismo d’azione non è ancora stato totalmente chiarito e non esiste una teoria comunemente accettata. Situazione analoga si riscontra per quanto riguarda gli effetti biologici dei campi elettromagnetici di bassa intensità e frequenza. Tali effetti, che dipendono in modo complesso dalla intensità e frequenza del campo magnetico e dalla durata del trattamento (10), sono stati ampiamente studiati sull’uomo e sugli animali e, negli ultimi anni e in misura sicuramente minore, sulle piante (11). Anche in questo caso sono state formulate numerose ipotesi per spiegare l’interazione di tali campi con il bio-oggetto (12-14), ma finora non si hanno risposte certe. Omeopatia ed elettromagnetismo potrebbero essere interpretate, alla luce del relativamente recente paradigma fisico quanto-elettrodinamico, come due facce della stessa moneta spendibile per soddisfare, in chiave sia teorica che sperimentale, le esigenze di complesse dinamiche biologiche in cerca di una propria riconoscibile e specifica identità. Una migliore comprensione del meccanismo d’azione sia dei medicinali omeopatici che dei campi elettromagnetici deboli potrebbe essere raggiunta grazie all’uso di modelli in vitro e in vivo nei quali la correlazione trattamento/effetto è più diretta e quindi più facilmente interpretabile (15). Tra questi, i modelli vegetali presentano numerosi vantaggi come l’assenza di effetto placebo e di problemi etici, l’impiego di materiale biologico economico e pressoché inesauribile, la possibilità di condurre un elevato numero di prove in tempi ragionevolmente brevi e di poter quindi disporre di un’ampia base di dati per un’approfondita analisi statistica (16). Scopo della nostra ricerca è: i) fornire un contributo sperimentale per la valutazione degli effetti biologici delle alte diluizioni omeopatiche e di trattamenti elettromagnetici, mediante esperimenti standardizzati basati su modelli vegetali; ii) identificare un’eventuale similarità tra gli effetti biologici della potentizzazione omeopatica e dell’esposizione elettromagnetica.
Bibliografia
1. Shang A. et Al. Are the clinical effects of homoeopathy placebo effects? Comparative study of placebo-controlled trials of homoeopathy and allopathy. The Lancet, 2005; 366(9487): 726-732
2. Bellavite P. et Al. Homeopathy and placebo. Homeopathy, 2006; 95(1): 51
3. Frass M. et Al. Asymmetry in The Lancet meta-analysis. Homeopathy, 2006; 95(1): 52-53
4. Zacharias CR. Physical research in dynamized systems. Medical Hypotheses, 2002; 58: 523-526.
5. Hyland M.E. et Al. Oscillatory effects in a homeopathic clinical trial: an explanation using complexity theory, and implications for clinical practice. British Homeopathic Journal, 2002; 9: 145-149
6. Bellavite P. Complexity science and homeopathy: a synthetic overview. Homeopathy, 2003; 92(4): 203-212
7. Roy R. et Al. The structure of liquid water; Novel insights from materials research; Potential relevance to homeopathy. Materials Research Innovations, 2005; 9(4): 98-103
8. Elia V. et Al. The “Memory of Water”: an almost deciphered enigma. Dissipative structures in extremely dilute aqueous solutions. Homeopathy, 2007; 96, 163-169
9. Nani D.et Al. Role of variability in evaluating ultra high dilution effects: considerations based on plant model experiments. Forschende Komplementarmedizin, 2007; 14: DOI: 10.1159/000108281
10. Ruzic R.et Al. Weak magnetic field decreases heat stress in cress seedlings. Electromagnetic Biology and Medicine, 2002; 21: 69-80
11. Galland P. et Al. Magnetoreception in plants. Journal of Plant Research, 2005; 118:371-389.
12. Goldworthy A. et Al. Biological effects of physically conditioned water. Water Research, 1999; 33: 1618-1626
13. Lobyshev V. I. Water is a sensor to weak forces including electromagnetic fields of low intensity. Electromagnetic Biology and Medicine, 2005; 24:..
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NanI Sialidase Enhances the Action of Clostridium perfringens Enterotoxin in the Presence of Mucus
No full textClostridium perfringens enterotoxin (CPE) is the main virulence factor for C. perfringens type F strains to cause human gastrointestinal diseases, which can involve lethal enterotoxemia. During type F disease, CPE encounters an adherent mucus layer overlying the intestines, so the current study evaluated if NanI potentiates CPE activity in the presence of adherent mucus. CPE alone caused more cytotoxicity transepithelial electrical resistance (TEER) and permeability to fluorescent dextran (FD) for minimal mucus-producing HT29 cells versus that in their derivative HT29-MTX-E12 cells, which produce abundant adherent mucus. However, for HT29-MTX-E12 cells, the presence of NanI significantly increased CPE binding and pore formation, which enhanced their sensitivity to CPE effects on cytotoxicity, TEER, and FD permeability. When the ability of NanI to potentiate CPE-induced enterotoxemia was then tested in a mouse small intestinal loop enterotoxemia model, a pathophysiologically relevant 50 μg/mL dose of CPE did not kill mice. However, the copresence of purified NanI resulted in significant CPE-induced lethality. More CPE was detected in the sera of mice challenged with 50 μg/mL of CPE when NanI was copresent during challenge. The copresence of NanI and CPE during challenge also significantly increased intestinal histologic damage compared to that after challenge with CPE alone, suggesting that NanI enhancement of CPE-induced intestinal damage may increase CPE absorption into blood. Overall, these results indicate that (i) mucus inhibits CPE action and (ii) NanI can potentiate CPE action in the presence of mucus, which may help explain why type F strains that produce relatively low levels of CPE are still pathogenic. IMPORTANCE NanI is a sialidase produced by some Clostridium perfringens type F strains. Here, we found that NanI can significantly increase the action of C. perfringens enterotoxin (CPE), which is the main toxin responsible for severe human enteric disease caused by type F strains. This effect likely helps to explain why even some type F strains that produce small amounts of CPE are pathogenic
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NanI Sialidase Is an Important Contributor to Clostridium perfringens Type F Strain F4969 Intestinal Colonization in Mice
No full textClostridium perfringens type F (formerly enterotoxigenic C. perfringens type A) strains produce an enterotoxin (CPE) to cause acute cases of food poisoning and chronic nonfoodborne human gastrointestinal diseases (NFD), e.g., antibiotic-associated diarrhea (AAD). NFD strains also produce NanI sialidase, an extracellular enzyme that releases sialic acids from sialyated host macromolecules. Recent in vitro studies suggested that NanI may contribute to NFD strain intestinal colonization by enhancing the adherence of such strains to intestinal cells and promoting their bacterial growth using generated sialic acid as an energy source. The current study tested this hypothesis by developing a mouse intestinal colonization model involving clindamycin pretreatment to produce conditions mimicking those during AAD. In this model, the type F NFD strain F4969 persisted for at least 4 days in the small intestine, cecum, and colon. When clindamycin-pretreated mice were challenged by oral gavage with equivalent numbers of F4969 bacteria or its isogenic nanI null mutant, significantly lower numbers of the nanI mutant were recovered from all intestinal segments, and it was completely cleared from the small intestine by day 4. Complementation of the mutant to restore NanI production also promoted colonization. When the same nanI null mutant strain was coinoculated into the mouse model together with a nanI-producing strain, the numbers of this mutant were restored to wild-type F4969 levels in all intestinal segments. This result suggests that sialidases produced by other bacteria might also provide some support for C. perfringens intestinal colonization. Collectively, these in vivo findings identify NanI to be the first known significant contributor to chronic intestinal colonization by NFD strains
Transient oxidative stress evokes early changes in the functional properties of neonatal rat hypoglossal motoneurons in vitro
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