1,721,191 research outputs found
Tossicologia dell'amatriciana. Lo scandalo del peperoncino colorato con Sudan I nasce dall'arbitrarietà del processo di valutazione dei rischi e dagli errori di comunicazione
No full textThe search for the physiological functions of NTE; is NTE a receptor?
No full textNeuropathy target esterase (NTE) was identified as the molecular target for organophosphate-induced delayed polyneuropathy several years ago but its physiological functions are still unknown. The mechanism which initiates neuropathy was thought to be a two step process: inhibition (phosphorylation) of NTE and aging of phosphorylated NTE. Depending on the occurrence of the second reaction (aging), inhibitors were ranked as neuropathic (forming an ageable NTE) and non-neuropathic (forming a non-ageable NTE). Non-neuropathic inhibitors protect from neuropathy if given before the neuropathic ones, because they occupy the catalytic centre of NTE. Thus the catalytic function of NTE seems irrelevant in maintaining the health of neurons. This paper reviews some new information concerning the interaction of NTE with its inhibitors as well as on a phenomenon called promotion of neuropathy. Some inhibitors which apparently form a non-ageable inhibited NTE were found to cause neuropathy, even though some of them must be given at very high doses. Moreover some 'non-neuropathic-protective' NTE inhibitors were found to exacerbate (promote) neuropathy when given after a neuropathic one. It is likely that the target for promotion is other than NTE. The hypothesis that NTE has some unknown receptorial functions where inhibitors act with different efficacy is discussed. NTE inhibitors have been ranked as full agonists (classic neuropathic inhibitors such as diisopropylfluorophosphate), partial agonists (protective or neuropathic, depending on the dose, such as methamidophos) and antagonists (protective, and neuropathic at the highest doses, such as phenylmethanesulfonyl fluoride). Age-related differences in the 'receptor' NTE might be responsible for the different sensitivities of juvenile and adult animals
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
The relevance of inhibitor-substrate interactions when measuring neuropathy target esterase inhibition
No full textNeuropathy target esterase (NTE), thought to be the target for organophosphate polyneuropathy, is operationally defined as that neural phenyl valerate esterase resistant to paraoxon (40 microM) and sensitive to mipafox (50 microM; 20 min, pH 8.0, 37 degrees C). The time course of inhibition of particulate paraoxon pretreated esterases by mipafox showed that the lines indicating the rate of inhibition did not pass through the log 100% activity when extrapolated at zero time. Slopes of inhibition of NTE were not linearly related to the concentration of mipafox. Kinetic parameters derived from Wilkinson type plots were: Ka = 49-199 microM, k(+2) = 0.24-0.64 min(-1) and k(a) = 3.1-5.0 mM(-1) m(-1). When mipafox was removed (either by dilution or centrifugation) before the addition of phenyl valerate intercepts below 100% disappeared. We confirm that the formation of Michaelis complex between NTE and mipafox is not prevented by phenyl valerate and that inhibition proceeds after addition of phenyl valerate. We compared inhibitions obtained with experiments by using the traditional method (sequential incubation with inhibitors and phenyl valerate) to those obtained with a method where mipafox is removed before the addition of substrate. When calculating fixed-time 50% inhibitory concentrations (IC50s) of some inhibitors for NTE, the longer the hydrolysis time, the lower were the IC50s. Therefore, the inhibitory potency of certain NTE inhibitors, is accurately assessed only when calculating second-order rate constants (k(a))
Studio di esterasi del fenil benzoato nella promozione della polineuropatia ritardata da organofosforici nei nervi periferici di gallina
No full textVariations on the Author
Full text link“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
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