1,720,963 research outputs found
Sphingosine-1-phosphate as survival factor in etoposide-induced cytotoxicity in glioma cells: role of PI3K/Akt-dependent stimulation of endoplasmic reticulum (ER) to Golgi apparatus ceramide traffic
No full text
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
Ceramide in beta cells apoptosis induced by gluco-lipotoxicity:possible role of cer flow for the biosynthesis of complex sphingolipids
No full textCERAMIDE IN BETA CELLS APOPTOSIS INDUCED BY GLUCO-LIPOTOXICITY: POSSIBLE ROLE OF CER FLOW FOR THE BIOSYNTHESIS OF COMPLEX SPHINGOLIPIDS
P. Giussani1, H. Le Stunff2, E. Gjoni1, J. Veret2, L. Riboni1, P. Viani1
1Department of Medical Chemistry, Biochemistry and Biotechnology, University of Milano, LITA Segrate, Via Fratelli Cervi, 93, 20090 Segrate (MI) Italy
2Unité Biologie Fonctionnelle et Adaptative - EAC CNRS 4413, Laboratoire de Biologie et Pathologie du Pancréas Endocrine, Université PARIS- DIDEROT (7),4, rue Marie-Andrée Lagroua Weill-Halle, 75205 PARIS Cedex 13 France
Background: In type 2 diabetes the detrimental effects of chronic exposure to NEFA, in particular palmitate, on beta cell function and viability have been correlated to hyperglycaemia. De novo synthesis of ceramide (Cer) and ER stress are among the molecular pathways and regulators involved in these negative effects. In order to gain insight into the molecular mechanism(s) of gluco-lipotoxicity we studied the effect of palmitate and high glucose concentrations on ceramide metabolism in INS-1 cells.
Results: The results obtained demonstrated that in INS-1 cells palmitate and glucose taken separately did not induce cell death, whereas the combined treatment with both nutrients resulted in an extensive cell apoptosis and this was associated to a significant increase of Cer levels. The presence of fumonisin-B1 partially reversed the apoptosis induced by the combined treatment with palmitate and glucose thus suggesting a role for ER-associated Cer in gluco-lipotoxicity in INS-1 cells. Metabolic studies show that treatment with palmitate results in the inhibition of Cer utilization for SM biosynthesis. Fluorescence microscopy studies suggest a reduced ER to Golgi flow of Cer. To evaluate if Cer accumulation could be due to a defect in the vesicular and/or CERT-mediated transport of Cer, we studied Cer metabolism in INS-1 cells silenced for CERT incubated with glucose in the presence or not of palmitate. In downregulated cells palmitate inhibited Cer utilization for SM biosynthesis; these results indicated that the vesicle-mediated transport is involved in the reduced ER to Golgi flow of Cer.
Conclusions: Altogether these data suggest that the accumulation of Cer can be due to a decrease in utilization of newly synthesized Cer for SM biosynthesis thus supporting a role of ER-associated Cer in the regulation of beta cell death induced by gluco-lipotoxicity
Sphingosine-1-phosphate promotes survival against etoposide by enhancing ceramide transport from ER to Golgi apparatus in T98G glioma cells
No full textCeramide in beta cell apoptosis induced by gluco-lipotoxicity: possible role of cer flow for the biosynthesis of complex sphingolipids
No full textBackground: In type 2 diabetes the detrimental effects of chronic exposure to NEFA, in particular palmitate, on beta cell function and viability have been correlated to hyperglycaemia. De novo synthesis of ceramide (Cer) and ER stress are among the molecular pathways and regulators involved in these negative effects. In order to gain insight into the molecular mechanism(s) of gluco-lipotoxicity we studied the effect of palmitate and high glucose concentrations on ceramide metabolism in INS-1 cells.
Results: The results obtained demonstrated that in INS-1 cells palmitate and glucose taken separately did not induce cell death, whereas the combined treatment with both nutrients resulted in an extensive cell apoptosis and this was associated to a significant increase of Cer levels. The presence of fumonisin-B1 partially reversed the apoptosis induced by the combined treatment with palmitate and glucose thus suggesting a role for ER-associated Cer in gluco-lipotoxicity in INS-1 cells. Metabolic studies show that treatment with palmitate results in the inhibition of Cer utilization for SM biosynthesis. Fluorescence microscopy studies suggest a reduced ER to Golgi flow of Cer. To evaluate if Cer accumulation could be due to a defect in the vesicular and/or CERT-mediated transport of Cer, we studied Cer metabolism in INS-1 cells silenced for CERT incubated with glucose in the presence or not of palmitate. In downregulated cells palmitate inhibited Cer utilization for SM biosynthesis; these results indicated that the vesicle-mediated transport is involved in the reduced ER to Golgi flow of Cer.
Conclusions: Altogether these data suggest that the accumulation of Cer can be due to a decrease in utilization of newly synthesized Cer for SM biosynthesis thus supporting a role of ER-associated Cer in the regulation of beta cell death induced by gluco-lipotoxicity
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
Ceramide in gluco-lipotoxicity: possible impairment of ceramide flowing in complex sphingolipid biosynthesis in beta pancreatic cells
No full textCeramide flow from the endoplasmic reticulum to the Golgi apparatus is impaired in glucolipotoxic conditions in INS-1 beta cells
No full textCeramide flow from the Endoplasmic Reticulum to the Golgi apparatus is impaired in Glucolipotoxic conditions in INS-1 cells
Giussani Paola1, Gjoni Enida1, Cinque Alessandra1, Le Stunff Hervé2, Riboni Laura1, Viani Paola1
1Department of Medical Biotechnology and Translational Medicine, University of Milano, LITA Segrate, Via Fratelli Cervi, 93, 20090 Segrate (MI) Italy
2Unité Biologie Fonctionnelle et Adaptative - EAC CNRS 4413, Laboratoire de Biologie et Pathologie du Pancréas Endocrine, Université PARIS- DIDEROT (7),4, rue Marie-Andrée Lagroua Weill-Halle, 75205 PARIS Cedex 13 France
In type 2 diabetes the detrimental effects of chronic exposure to NEFA, in particular palmitate, on -cell function and viability have been associated to hyperglycaemia. ER stress is among the molecular pathways and regulators involved in these negative effects. Moreover, it is known that accumulation of ceramide due to glucolipotoxicity can be associated to the induction of ER stress. The increased ER ceramide levels can be due to an enhanced ceramide biosynthesis and a decrease in ceramide utilization as well. In the control of ER ceramide levels it is crucial ceramide trafficking between ER and Golgi, which represents the site of complex sphingolipid biosynthesis. In order to gain insight into the molecular mechanism(s) of glucolipotoxicity we studied the effect of glucolipotoxic conditions on ceramide traffic in INS-1 cells.
Metabolic studies show that treatment with palmitate results in the inhibition of ceramide utilization for SM and glycosphingolipid biosynthesis. Fluorescence microscopy studies suggest a reduced ER to Golgi flow of ceramide. To evaluate if ceramide accumulation could be due to a defect in the vesicular and/or CERT-mediated transport of ceramide we studied CERT expression and ceramide metabolism in INS-1 cells silenced for CERT incubated with glucose in the presence or not of palmitate. Glucolipotoxicity decreased the total amount of CERT and, by inducing CERT phosphorylation, prevented its localization to the Golgi of pancreatic -cells. Moreover in CERT-downregulated cells palmitate still inhibited ceramide utilization for SM biosynthesis. These results demonstrate that both the vesicular-mediated and CERT-mediated transport are involved in the reduced ER to Golgi flow of ceramide in glucolipotoxic conditions.
Altogether these data suggest that the accumulation of ceramide can be due to a decrease in utilization of newly synthesized ceramide for SM biosynthesis thus supporting a role of ER-associated ceramide in the regulation of -cell death induced by gluco-lipotoxicity
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