1,720,984 research outputs found
Effetto dell'Ambiente Arricchito in un modello animale di Encefalomielite Autoimmune Sperimentale e nell'Invecchiamento.
No full textEffect of the Enriched Environment in an animal model of Experimental Autoimmune Encephalomyelitis and in Aging
The Functional cross-talk between nicotinic and glutamatergic receptors on dopaminergic nerve terminals in the rat nucleus accumbens
No full textMicronuclei Induction and Neurotoxic Effect in C6 Glioma Cells Exposed to Low Concentrations of Diazinon, an Organophosphorus Compound
No full textAbstract
Background: The presence of doses of diazinon far lower than
IC50 cholinesterase activity was reported in plasma of pregnant
women and newborns living in agricultural areas.
Objective: In the current study, we investigated the possibility of
neurotoxicity induction by exposing cultured gliotypic C6 cells to a
similar range of concentrations, for 24 h, at 37°C.
Materials and methods: Confluent C6 cellswere exposed to
diazinon (DZN) at concentrations from 200ng/L to 0.002ng/L. The
maintenance of confluence, the induction of micronuclei and the
expression of molecules related to the cholinergic system were
verified, by morphological, biochemical and immunohistochemical
methods, in order to check the effects of the altered modulation of
the cholinergic signal on glial-like cells.
Results: The exposure to 0.002ng/L showed significant effecton
micronuclei occurrence since the exposure to 0.002ng/L, while
the inhibition on butyrylcholinesterase activity showed significant
variations starting from the exposure to 0.2ng/L up to 200ng/L.
Acetylcholinesterase activity was significantly inhibited only by
the exposure to 200ng/L. The immunohistochemical localization
of choline acetyltransferase and fibronectin showed dramatic
variation only in C6 cells exposed to 200ng/L.
Conclusion: The low doses of DZN investigated affect the
investigated features of glial-like cells, mainly starting from the
0.2ng/L dose, while the effects on AChE activity and ChAT and
fibronectin-immuorectivity were clearly exerted in cell cultures
exposed to 200ng/L. Collectively, these findings translated to the
in vivo functions of glial cells indicate that exposure to doses that
are nontoxic to adult organisms may weaken the brain defense and
functions of glial cells through an AChE-mediated mechanism
Urea affects the olfactory epithelium in developing Danio rerio: a possible role of nitric oxide
No full textChronic renal disease causes olfactory impairment through an unknown mechanism. Chondrichthyes, a class of vertebrates characterized by high plasma urea concentration, lack olfactory cilia and the G protein alpha subunit olfactory-type (Gαolf - marker of the olfactory receptor neurons in vertebrates) in their olfactory neuroepithelium (ONE). Despite of that, there is no data in the literature about a direct action of urea on the ONE.
In this study, Danio rerio embryos were exposed to 75 mM urea concentrations from 24 to 96 hours post fertilization. The endocytosis of Neutral Red dye in the olfactory mucosa were detected in control and urea-exposed larvae as a marker of binding and internalization of the Olfactory Receptors. The presence and distribution of Gαolf were investigated in the olfactory epithelium of control and urea-exposed larvae, using a commercial antibody. As Nitric oxide (NO) has important roles in the ONE and urea is known to affect its production, we evaluated, in control and urea-treated larvae, the presence of NO synthase (NOS) in the ONE using immunohistochemistry and a histoenzymatic reaction. We also exposed D. rerio larvae to a NOS-inhibitory molecule, NG-L-Nitro-Arginine (L-NArg), comparing them to the control and urea-treated fishes. Both Gαolf and NOS were increased in urea- and L-NArg-treated fishes than in the control, while the Neutral Red internalization was unaffected.
Different hypotheses can be made about the effect of urea on NO production in the olfactory epithelium and, more speculatively, also about the role of NO on the Gαolf synthesis/degradation. Further investigations are needed in order to understand the real effects of urea on the olfactory system of pathologically and physiologically uremic vertebrates
Morpho-functional approach to neurotransmission and osmoregulation in Amphibalanus amphitrite cyprid (Cirripedia, Crustacea)
No full textAcorn barnacles are cirripedian crustacea with a sessile adult stage, that live in a calcareous shell attached to a submersed substrate and filter food with its limbs. Barnacles show various naupliar stages and a cyprid, the final lecithotrophic stage competent for settlement. Due to their ability to adhere, barnacles are important constituents of biofouling. To obtain biological data useful to develop antifouling strategies, many studies are focused on cyprid anatomy and neuroendocrinology, especially in Amphibalanus amphitrite due to its worldwide distribution. With our work we wanted to map the distribution of neurotransmitters in the cyprid to provide data for research on barnacle development, new antifouling strategies and the use of cyprid as a model organism in ecotoxicology. We focused on the distribution of neuroactive substances related to different systems: serotonergic, cholinergic, FMRFamidergic-like, GABAergic, glutamatergic and nitrergic. Also the functional aspects were investigated through physiological assessment, pointing out on swimming and settling activities. The cholinergic (our data) and the octopaminergic (from the literature) systems are known as potential target in antifouling strategies; moreover we suggest that serotonergic and GABAergic systems could be pharmacologically targeted as well, because they are widely present in the cyprid sensory and nervous structures. We are now focusing also on osmoregulative processes, attempting to characterize the presence and distribution of aquaporins, as they could be of interest in both antifouling strategies and ecotoxicology. To date, our data are consistent with the literature about ion-exchanging sites in the cyprid
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
Variations 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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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