1,720,987 research outputs found
Involvement of protein kinase Cε in the stimulation of anionic amino acid transport in cultured human fibroblasts
No full textProtein kinase C (PKC) activation stimulates transport system X-(AG) for anionic amino acids in cultured human fibroblasts (Franchi-Gazzola, R., Visigalli, R., Bussolati, O., and Gazzola, G. C. (1994) FEBS Lett. 352, 109- 112). To identify which PKC isoform is responsible for this effect, aspartate transport through system X-(AG), PKC activity, and the subcellular distribution of PKC isoforms have been studied before and after treatment with phorbol 12,13-dibutyrate (PDBu) in fibroblasts maintained at low serum for 1 (control cells) or 7 days (quiescent cells). In control cells aspartate transport and PKC activity in the particulate fraction were stimulated by short term PDBu treatment; both stimulatory effects were down-regulated by a prolonged exposure to the phorbol. In contrast, in quiescent cells aspartate transport and particulate PKC activity were higher than control under basal conditions, unaffected by a short term PDBu treatment, and lowered by a prolonged incubation with the phorbol. In both control and quiescent cells a short term PDBu treatment modified PKCα distribution, increasing its membrane-associated fraction. PKCδ was mostly in the soluble fraction and scarcely sensitive to PDBu. A brief exposure to PDBu increased membrane- associated PKCε in control but not in quiescent cells. In these cells ε isoform was found exclusively in the particulate fraction even in PDBu- untreated cells. A prolonged PDBu treatment caused a partial down-regulation of membrane-associated PKCε in control cells and its marked decrease in quiescent cells. It is concluded that PKC-dependent changes in system X(AG)- activity parallel the behavior of PKCε, thus suggesting a specific role for this isoform in system X(AG)- regulation
Erratum: Functional analysis of OCTN2 and ATB0,+ in normal human airway epithelial cells (PLoS ONE (2020) 15:2 (e0228568) DOI: 10.1371/journal.pone.0228568)
No full textThere is an error in reference 12. The correct reference is: Ingoglia F, Visigalli R, Rotoli BM, Barilli A, Riccardi B, Puccini P, et al. (2016) Functional activity of L-carnitine transporters in human airway epithelial cells. Biochim Biophys Acta. 1858(2):210–9. 10.1016/j.bbamem.2015. 11.013
Involvement of protein kinase C epsilon in the stimulation of anionic amino acid transport in cultured human fibroblasts
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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
Transduction pathways involved in the stimulation of arginine transport by TNF-alpha in human endothelial cells
No full textAppropriate 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
LPS and TNF alpha increase arginine transport but not nitric oxide production in cultured human endothelial cells
No full textTwo-way arginine transport in human endothelial cells: TNF-alpha stimulation is restricted to system y(+)
No full textHuman umbilical vein endothelial cells transport arginine through two Na(+)-independent systems. System y(+)L is insensitive to N-ethylmaleimide (NEM), inhibited by L-leucine in the presence of Na(+), and referable to the expression of SLC7A6/y(+)LAT2, SLC7A7/y(+)LAT1, and SLC3A2/4F2hc. System y(+) is referable to the expression of SLC7A1/CAT1 and SLC7A2/CAT2B. Tumor necrosis factor-alpha (TNF-alpha) and bacterial lipopolysaccharide induce a transient stimulation of arginine influx and efflux through system y(+). Increased expression of SLC7A2/CAT2B is detectable from 3 h of treatment, while SLC7A1 expression is inhibited at later times of incubation. System y(+)L activity and expression remain unaltered. Nitric oxide synthase type 2 mRNA is not detected in the absence or presence of TNF-alpha, while the latter condition lowers nitric oxide synthase type 3 expression at the mRNA and the protein level. Nitrite accumulation is comparable in cytokine-treated and control cells up to 48 h of treatment. It is concluded that modulation of endothelial arginine transport by TNF-alpha or lipopolysaccharide occurs exclusively through changes in CAT2B and CAT1 expression and is dissociated from stimulation of nitric oxide production.Human umbilical vein endothelial cells transport arginine through two Na+-independent systems. System y+L is insensitive to N-ethylmaleimide (NEM), inhibited by L-leucine in the presence of Na+, and referable to the expression of SLC7A6/y+LAT2, SLC7A7/y+LAT1, and SLC3A2/4F2hc. System y+ is referable to the expression of SLC7A1/CAT1 and SLC7A2/CAT2B. Tumor necrosis factor-α (TNF-α) and bacterial lipopolysaccharide induce a transient stimulation of arginine influx and efflux through system y+. Increased expression of SLC7A2/CAT2B is detectable from 3 h of treatment, while SLC7A1 expression is inhibited at later times of incubation. System y+L activity and expression remain unaltered. Nitric oxide synthase type 2 mRNA is not detected in the absence or presence of TNF-α, while the latter condition lowers nitric oxide synthase type 3 expression at the mRNA and the protein level. Nitrite accumulation is comparable in cytokine-treated and control cells up to 48 h of treatment. It is concluded that modulation of endothelial arginine transport by TNF-α or lipopolysaccharide occurs exclusively through changes in CAT2B and CAT1 expression and is dissociated from stimulation of nitric oxide production
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