Human glycated albumin affects glucose metabolism in L6 skeletal muscle cells by impairing insulin-induced insulin receptor substrate (IRS) signaling through a protein kinase C alpha-mediated mechanism.

Nonenzymatic glycation is increased in diabetes and leads to increased levels of glycated proteins. Most studies have focused on the role of glycation products in vascular complications. Here, we have investigated the action of human glycated albumin (HGA) on insulin signaling in L6 skeletal muscle cells. Exposure of these cells to HGA inhibited insulin-stimulated glucose uptake and glycogen synthase activity by 95 and 80%, respectively. These effects were time- and dose-dependent, reaching a maximum after 12 h incubation with 0.1 mg/ml HGA. In contrast, exposure of the cells to HGA had no effect on thymidine incorporation. Further, HGA reduced insulin-stimulated serine phosphorylation of PKB and GSK3, but did not alter ERK1/2 activation. HGA did not affect either insulin receptor kinase activity or insulin-induced Shc phosphorylation on tyrosine. In contrast, insulin-dependent IRS-1 and IRS-2 tyrosine phosphorylation was severely reduced in cells preincubated with HGA for 24 h. Insulin-stimulated association of PI3K with IRS-1 and IRS-2, and PI3K activity were reduced by HGA in parallel with the changes in IRS tyrosine phosphorylation, while Grb2-IRS association was unchanged. In L6 myotubes, exposure to HGA increased PKC activity by 2-fold resulting in a similar increase in Ser/Thr phosphorylation of IRS-1 and IRS-2. These phosphorylations were blocked by the PKC inhibitor bisindolylmaleimide (BDM). BDM also blocked the action of HGA on insulin-stimulated PKB and GSK3 alpha. Simultaneously, BDM rescued insulin-stimulation of glucose uptake and glycogen synthase activity in cells exposed to HGA. The use of antibodies specific to PKC isoforms shows that this effect appears to be mediated by activated PKC alpha, independent of reactive oxygen species production. In summary, in L6 skeletal muscle cells, exposure to HGA leads to insulin resistance selectively in glucose metabolism with no effect on growth-related pathways regulated by the hormone

De las catacumbas a los últimos confines: violencia, sentido y representación en los periplos del martirio

En este trabajo propongo un análisis transversal de las figuras del mártir y del martirio. Recurriendo a la noción de mediación, en la primera parte analizo el rol protagónico de las representaciones del martirio en las prácticas de la memoria durante la segunda mitad del siglo XVI. Analizo algunas de las condiciones que contribuyeron a la emergencia de una "cultura del martirio" y el rol de las mediaciones en tal surgimiento. En la segunda parte, estudio la forma en que el (re)descubrimiento de las catacumbas romanas, abrió un campo de producción de sentido en torno a la figura del martirio. En la tercera parte, centrándome en la Compañía de Jesús, analizo algunas mediaciones a través de las cuáles las figuras del martirio transgredieron las fronteras de iglesias y conventos para proyectarse a los últimos confines en un mundo en plena expansión.Neste artigo proponho uma análise transversal das figuras do mártir e do martírio. Usando a noção de mediação, na primeira parte eu tento analisar o papel de liderança de representações de martírio em práticas de memória durante a segunda metade do século XVI. Eu analiso algumas das condições que contribuíram para o surgimento de uma "cultura do martírio" e o papel da mediação nesta emergência. Na segunda parte, eu estudo como a (re) descoberta das catacumbas romanas abriu um campo de produção de significados em torno da figura do martírio. Na terceira parte, com foco na Companhia de Jesus, analiso algumas mediações pelas quais as representações do martírio transgrediram as fronteiras de igrejas e conventos para se projetar nas fronteiras de um mundo em plena expansão mundial.This paper proposes a cross-sectional analysis of martyr and martyrdom. Through the notion of mediation, in the first part I analyze the leading role of representations of martyrdom in memory practices during the second half of the sixteenth century. I analyze some of the conditions that contributed to the emergence of a "martyrdom's culture" and the role of mediation in such emergence. The second part studies how the (re)discovery of the Roman catacombs encouraged the production of meanings around the figure of martyrdom. In the third part, focusing on the Society of Jesus, I analyze a few instances of mediation through which the figures of martyrdom transgressed the boundaries of churches and convents to project themselves to the last frontiers of a world in full expansion.Fil: Salamanca Villamizar, Carlos Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Ets-1 Confers Cranial Features on Neural Crest Delamination

Neural crest cells (NCC) have the particularity to invade the environment where they differentiate after separation from the neuroepithelium. This process, called delamination, is strikingly different between cranial and trunk NCCs. If signalings controlling slow trunk delamination start being deciphered, mechanisms leading to massive and rapid cranial outflow are poorly documented. Here, we show that the chick cranial NCCs delamination is the result of two events: a substantial cell mobilization and an epithelium to mesenchyme transition (EMT). We demonstrate that ets-1, a transcription factor specifically expressed in cranial NCCs, is responsible for the former event by recruiting massively cranial premigratory NCCs independently of the S-phase of the cell cycle and by leading the gathered cells to straddle the basal lamina. However, it does not promote the EMT process alone but can cooperate with snail-2 (previously called slug) to this event. Altogether, these data lead us to propose that ets-1 plays a pivotal role in conferring specific cephalic characteristics on NCC delamination

Analyse de l'endémisme dans la faune des eaux courantes de la Corse

Corsica, along with the Iberian Peninsula and the Caucasian range, represents one of the most important centers of endemism for the fauna of Europe's fresh and running waters. The Plecoptera, Trichoptera and Diptera Blepharoceridae comprise the largest percentage of the endemic species . Endemicity is found primarily in the communities of springs and in the populations of streams at high altitudes. The phyletic and biogeographical origin of these endemic species from Corsica are analyzed. The Corsican endemisms are the remains of the European tertiary fauna which survived the insular shelter.La Corse représente, avec la Péninsule ibérique et le Caucase, un des centres les plus importants d1 endémisme pour la faune des eaux douces et des eaux courantes d'Europe. Les Plécoptères, Trichoptères et Diptères Blépharocérides renferment le plus fort pourcentage d'espèces endémiques. L'endémisme se manifeste principalement dans les communautés des sources et dans les peuplements des cours d'eau d'altitude élevée. L'origine pbylétique et biogéographique des espèces endémiques corses est analysée. Les endémiques corses représentent le reste de la faune tertiaire européenne qui s'est maintenu dans le refuge insulaire.Giudicelli Jean. Analyse de l'endémisme dans la faune des eaux courantes de la Corse. In: Ecologia mediterranea, tome 1,1975. pp. 133-147

Les stades préimaginaux des Blépharocérides (Diptera, Nematocera) de Corse. Etude taxonomique et écologique

La faune corse comprend 7 espèces de Blépharocérides. Le présent travail porte sur les stades préimaginaux de ces espèces qui sont figurés et décrits. Les 7 espèces peuvent être identifiées, à l'aide de caractères morphologiques simples, à l'état de larves, de nymphes et d'oeufs. Pour chaque espèce l'auteur donne les principales caractéristiques autoécologiques : amplitude altitudinale, cycle vital, répartition en fonction du type de cours d'eau

LES RHYACOPHILA ENDÉMIQUES DE CORSE. DESCRIPTION DE RHYACOPHILA TARDA n. sp. (TRICHOPTERA)

International audienc

LES RHYACOPHILA ENDÉMIQUES DE CORSE. DESCRIPTION DE RHYACOPHILA TARDA n. sp. (TRICHOPTERA)

International audienc

L'alpha-glucosidase neutre : structure et fonction de la proteine

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc