117,521 research outputs found
CILIARY NEUROTROPHIC FACTOR (CNTF) SIGNAL THROUGH STAT-3 SOCS3 PATWAY IN RAT PANCREATIC CELLS.
No full textCNTF is a cytokine that promotes survival and/or differentiation in many cell types, including rat pancreatic islets. In this work, we studied the mechanism of CNTF signal in neonatal rats pancreatic islets isolated by the collagenase method and cultured for 3 days in RPMI medium without (CTL) or with 1 nM of CNTF. The medium contained, when necessary, specific inhibitors of the PI3K, MAPK and JAK/STAT3 pathways. mRNA expression (RT-PCR) and protein phosphorylation (Western blot) of Akt, ERK1/2 and STAT3, and SOCS-3 (RT-PCR and Western blot), as well as glucose-stimulated insulin secretion (GSIS) (Radioimmunoassay), were analyzed. Our results showed that Akt, ERK1 and STAT3 mRNA expression, as well as phosphorylated Akt and ERK1/2, was not affected by CNTF treatment. CNTF increased cytoplasmatic and nuclear phosphorylated STAT3, and the SOCS3 mRNA and protein expression. In addition, CNTF lowered apoptosis and impaired GSIS. These effects were blocked by the JAK inhibitor, AG490 and by the STAT3 inhibitor Curcumin, but not by the MAPK inhibitor, PD98059, nor by the PI3K inhibitor, Wortmannin. In conclusion, CNTF signals through the JAK2/STAT3 cascade, increases SOCS3 expression, impairs GSIS and protects neonatal pancreatic rat islets from cytokine-induced apoptosis. These findings indicate that CNTF may be a potential therapeutic tool against Type 1 and/or Type 2 diabetes
Exercise training protects human and rodent β cells against endoplasmic reticulum stress and apoptosis
No full textProlonged exercise has positive metabolic effects in obese or diabetic individuals. These effects are usually ascribed to improvements in insulin sensitivity. We evaluated whether exercise also generates circulating signals that protect human and rodent β cells against endoplasmic reticulum (ER) stress and apoptosis. For this purpose, we obtained serum from humans or mice before and after an 8 wk training period. Exposure of human islets or mouse or rat β cells to human or rodent sera, respectively, obtained from trained individuals reduced cytokine (IL-1β+IFN-γ)- or chemical ER stressor-induced β-cell ER stress and apoptosis, at least in part via activation of the transcription factor STAT3. These findings indicate that exercise training improves human and rodent β-cell survival under diabetogenic conditions and support lifestyle interventions as a protective approach for both type 1 and 2 diabetes.-Paula, F. M. M. Leite, N. C. Borck, P. C. Freitas-Dias, R. Cnop, M. Chacon-Mikahil, M. P. T. Cavaglieri, C. R. Marchetti, P. Boschero, A. C. Zoppi, C. C. Eizirik, D. L. Exercise training protects human and rodent β cells against endoplasmic reticulum stress and apoptosis.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
Studio sulla tutela della salute e della sicurezza dei lavoratori del settore trasporti.
No full textPHARMACOLOGICAL CHARACTERIZATION OF [LEU-13-PSI-CH2NH-LEU14]-BOMBESIN AS A SPECIFIC BOMBESIN RECEPTOR ANTAGONIST ON ISOLATED SMOOTH-MUSCLE CELLS
No full textIsolated smooth muscle cells from guinea pig stomach were used to study the pharmacological characteristics of a newly synthetized bombesin analog, [Leu13-psi-CH2NH-Leu14]-bombesin (psi 13,14-BN) to function as antagonist of bombesin-induced contractile response. The antagonism caused by this new analog was compared to that obtained with the substance P analog [D-Arg1,D-Pro2,D-Trp7,9,Leu11]Substance P [( APTTL]SP), which has been used until now to characterize bombesin receptors on smooth muscle cells. psi 13,14-BN resulted to be more potent than [APTTL]SP as antagonist of bombesin action on smooth muscle. Comparing the IC50, psi 13,14-BN (IC50 70 nM) was 8 times more potent than [APTTL]SP (IC50 600 nM). In contrast to [APTTL] SP, the action of psi 13,14-BN was shown to be specific toward bombesin receptors in that it does not interfere with receptors for other agents (i.e., cholecystokinin, acetylcholine or substance P). The antagonism induced by both compounds was competitive inasmuch as the slope of the regression lines obtained by Schild plot analysis were not significantly different from the unity. The apparent affinity for the bombesin receptor was 0.8 nM for psi 13,14-BN and 7.8 nM for [APTTL]SP. These results indicate that psi 13,14-BN acts on isolated gastric smooth muscle cells as a competitive bombesin receptor antagonist, with a higher affinity and specificity than the substance P analog used previously
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Islet Neogenesis-associated Protein (ingap): The Role Of Its Endogenous Production As A Positive Modulator Of Insulin Secretion
No full textIslet neogenesis-associated protein (INGAP) is a peptide found in pancreatic exocrine-, duct- and islet- non-β-cells from normal hamsters. Its increase induced by either its exogenous administration or by the overexpression of its gene enhances β-cell secretory function and increases β-cell mass by a combination of stimulation of cell replication and islet neogenesis and reduction of β-cell apoptosis. We studied the potential modulatory role of endogenous INGAP in insulin secretion using two different experimental approaches. Hamster islets transfected with INGAP-small interfering RNA (INGAP-siRNA) were used to study glucose-stimulated insulin secretion (GSIS). In parallel, freshly isolated islets were incubated with high glucose and the same concentration of either a specific anti-INGAP rabbit serum or normal rabbit serum. INGAP-siRNA transfected islets reduced their INGAP mRNA and protein content by 35.1% and 47.2%, respectively whereas GSIS decreased by 25.8%. GSIS by transfected islets attained levels comparable to those recorded in control islets when INGAP pentadecapeptide (INGAP-PP) was added to the culture medium. INGAP antibody in the medium decreased significantly GSIS in a dose-dependent manner. These results indicate that endogenous INGAP plays a "physiological" positive modulatory role in insulin secretion, supporting its possible use in the treatment of prediabetes and Type 2 diabetes.1923034Pittenger, G.L., Vinik, A.I., Rosenberg, L., The partial isolation and characterization of ilotropin, a novel islet-specific growth factor (1992) Adv Exp Med Biol, 321, pp. 123-130Rafaeloff, R., Pittenger, G.L., Barlow, S.W., Qin, X.F., Yan, B., Rosenberg, L., Duguid, W.P., Vinik, A.I., Cloning and sequencing of the pancreatic islet neogenesis associated protein (INGAP) gene and its expression in islet neogenesis in hamsters (1997) J Clin Invest, 99, pp. 2100-2109Flores, L.E., García, M.E., Borelli, M.I., Del Zotto, H., Alzugaray, M.E., Maiztegui, B., Gagliardino, J.J., Expression of islet neogenesis-associated protein (INGAP) in islets of normal hamsters (2003) J Endocrinol, 177, pp. 243-248Del Zotto, H., Borelli, M.I., Flores, L., García, M.E., Gómez Dumm, C.L., Chicco, A., Lombardo, Y.B., Gagliardino, J.J., Islet neogenesis: an apparent key component of long-term pancreas adaptation to increased insulin demand (2004) J Endocrinol, 183, pp. 321-330Gagliardino, J.J., Del Zotto, H., Massa, L., Flores, L.E., Borelli, M.I., Pancreatic duodenal homeobox-1 and islet neogenesis-associated protein: a possible combined marker of activateable pancreatic cell precursors (2003) J Endocrinol, 177, pp. 249-259Barbosa, H., Bordin, S., Stoppiglia, L., Silva, K., Borelli, M., Del Zotto, H., Gagliardino, J., Boschero, A., Islet Neogenesis Associated Protein (INGAP) modulates gene expression in cultured neonatal rat islets (2006) Regul Pept, 136, pp. 78-84Barbosa, H.C., Bordin, S., Anhê, G., Persaud, S.J., Bowe, J., Borelli, M.I., Gagliardino, J.J., Boschero, A.C., Islet neogenesis-associated protein signaling in neonatal pancreatic rat islets: involvement of the cholinergic pathway (2008) J Endocrinol, 199, pp. 299-306Silva, K.E., Barbosa, H.C., Rafacho, A., Bosqueiro, J.R., Stoppiglia, L.F., Carneiro, E.M., Borelli, M.I., Boschero, A.C., INGAP-PP up-regulates the expression of genes and proteins related to K+ ATP channels and ameliorates Ca2+ handling in cultured adult rat islets (2008) Regul Pept, 148, pp. 39-45Madrid, V., Del Zotto, H., Maiztegui, B., Raschia, M.A., Alzugaray, M.E., Boschero, A.C., Barbosa, H.C., Gagliardino, J.J., Islet neogenesis-associated protein pentadecapeptide (INGAP-PP): mechanisms involved in its effect upon beta-cell mass and function (2009) Regul Pept, 157, pp. 25-31Paula, F.M., Barbosa, H.C., Carneiro, E.M., Persaud, S.J., Gagliardino, J.J., Boschero, A.C., Souza, K.L., Requirement of NF-kappaB signalling pathway for modulation of the cholinergic muscarinic M3 receptor expression by INGAP-PP in insulin-producing cells (2010) Eur J Pharmacol, 642, pp. 37-46Borelli, M.I., Stoppiglia, L.F., Rezende, L.F., Flores, L.E., Del Zotto, H., Boschero, A.C., Gagliardino, J.J., INGAP-related pentadecapeptide: its modulatory effect upon 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