1,720,988 research outputs found
Methylmercury interaction with lymphocyte cholinergic muscarinic receptors in developing rats
No full textCerebral cholinergic muscarinic receptors (MR) have been suggested as one of the sensitive biochemical endpoints of the central nervous system altered by developmental exposure to the widespread seafood contaminant methylmercury (MeHg). In adult rats, MeHg has been shown to alter MR binding both in the brain and lymphocytes, supporting the use of MR in blood cells as a surrogate marker of
CNS changes. The effects of MeHg have been evaluated on rat lymphocyte MR binding (using [3H]QNB as specific muscarinic ligand) in vivo (after perinatal exposure) and in vitro. For comparison, in vitro studies were also performed on human lymphocytes. Exposure to 1mg MeHg/kg/day during pregnancy and lactation (from GD7 to PND7) significantly enhanced lymphocyte MR density in both adult and young rats 21 days after delivery, with a more pronounced effect in the mothers (Bmax increase of 139%) than in the male offspring (+49%) and female offspring (+73%) as compared with their respective controls (3374, 4178, and 3774 fmol/million cells), in accordance with the higher Hg levels detected in the adult blood (11.372.2 mg/mL) than in pups (1.370.4 mg/L in both genders).
A lower MeHg dose (0.5 mg/kg/day) was without any effect on lymphocyte MRs. In in vitro studies, MeHg was an almost equipotent
inhibitor of 3H-QNB binding to rat and human lymphocyte MRs (IC50 values were 4.170.29, 5.270.51, and 5.070.9 mM for total rat
lymphocytes, rat T lymphocytes, and total human lymphocytes, respectively). Notably, the IC50 values for MeHg to lymphocyte MRs
were comparable to the Hg levels reached in blood (5–50 mM) of the PND21 rats exposed to MeHg.
The finding that the MR binding is a target for the effects of MeHg in peripheral blood cells is in accordance with our previous data in
brain [Coccini et al., 2006. Effects of developmental co-exposure to methylmercury and 2,20,4,40,5,50-hexachlorobiphenyl (PCB153) on
cholinergic muscarinic receptors in rat brain. Neurotoxicology, in press], and supports the use of this peripheral endpoint as a biomarker of MeHg-induced cerebral muscarinic alterations. The similarity of MeHg IC50 binding data between human and rat in peripheral tissues suggests the possible application of such biomarker to humans exposed to environmental chemical
“Monoammino ossidasi di tipo B e recettori muscarinici nel sangue periferico dei bambini ADHD come biomarker delle alterazioni del SNC”.
No full textComparative in vitro ex-vivo myelotoxicity of aflatoxins B1 and M1 on haematopoietic progenitors (BFU-E, CFU-E, and CFU-GM): Species-related susceptibility.
No full textHaemato- and myelotoxicity are adverse effects caused by mycotoxins. Due to the relevance of aflatoxins to human health, the present study, employing CFU-GM-, BFU-E- and CFU-E-clonogenic assays, aimed at (i) comparing, in vitro, the sensitivity of human vs. murine haematopoietic progenitors to AFB1 and AFM1 (0.001–50 lg/ml), (ii) assessing whether a single AFB1 in vivo treatment (0.3–3 mg/kg b.w.) alters the ability of murine bone marrow cells to form myeloid and erythroid colonies, and (iii) comparing the in vitro with the in vitro ex-vivo data. We demonstrated (i) species-related sensitivity to AFB1, showing higher susceptibility of human myeloid
and erythroid progenitors (IC50 values: about 4 times lower in human than in murine cells), (ii) higher sensitivity of CFU-GM and BFU-E colonies, both more markedly affected, particularly by AFB1 (IC50: 2.45 ± 1.08 and 1.82 ± 0.8 lM for humans, and 11.08 ± 2.92 and 1.81 ± 0.20 lM for mice, respectively), than the mature CFU-E (AFB1 IC50: 12.58 ± 5.4 and 40.27 ± 6.05 lM), irrespectively of animal species, (iii) regarding AFM1, a species- and lineage-related susceptibility similar to that observed for AFB1 and (iv) lack of effects after AFB1 in vivo treatment on the proliferation of haematopoietic colonies
PLASMA PHARMACOKINETICS OF CINMETACIN FOLLOWING ORAL-ADMINISTRATION IN HEALTHY-VOLUNTEERS
No full textThe pharmacokinetics of a single 600 mg oral dose of 1-cinnamoyl-2-methyl-5-methoxy-3-indolylacetic acid (cinmetacin, Cindomet) was studied in 8 healthy volunteers of both sexes. Plasma levels of the drug were assayed by using an HPLC technique ad hoc devised. Following administration, the Cmax was reached at the 2nd h in 7 out of 8 subjects with an average value of 18.19 micrograms/ml; 12 h after the dose (last sampling time) appreciable plasma levels of cinmetacin were measured, corresponding to 17.2% of the maximum average concentration. The mean values +/- S.E. concerning the elimination half-life, the total volume of distribution, the total plasma clearance and the total area under the curve were 3.80 +/- 0.21 h, 0.28 +/- 0.03 l/kg, 0.051 +/- 0.005 l/kg/h, and 125.64 +/- 15.97 micrograms.h/ml, respectively. The plasma decay of cinmetacin was monophasic and the data were interpreted according to a one-compartment open model. Overall results indicate that cinmetacin is well and rapidly absorbed orally and widely distributed in body fluids
Comparative analytical HPLC and ELISA studies for characterization of carbohydrate-deficient transferrin (CDT) isoforms in subjects with alcohol related problems.
No full textComparative in vitro ex-vivo myelotoxicity of aflatoxins B1 and M1 on haematopoietic (BFU-E, CFU-E, and CFU-GM): Species-related susceptibility.
No full textGoing 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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