Cloning and function of the rat colonic epithelial K+ channel K(V)LQT1

K(V)LQT1 (K(V)LQ1) is a voltage-gated K+ channel essential for repolarization of the heart action potential that is defective in cardiac arrhythmia. The channel is inhibited by the chromanol 293B, a compound that blocks cAMP-dependent electrolyte secretion in rat and human colon, therefore suggesting expression of a similar type of K+ channel in the colonic epithelium. We now report cloning and expression of K(V)LQT1 from rat colon. Overlapping clones identified by cDNA-library screening were combined to a full length cDNA that shares high sequence homology to K(V)LQT1 cloned from other species. RT-PCR analysis of rat colonic musoca demonstrated expression of K(V)LQT1 in crypt cells and surface epithelium. Expression of rK(V)LQT1 in Xenopus oocytes induced a typical delayed activated K+ current. that was further activated by increase of intracellular cAMP but not Ca2+ and that was blocked by the chromanol 293B. The same compound blocked a basolateral cAMP-activated K+ conductance in the colonic mucosal epithelium and inhibited whole cell K+ currents in patch-clamp experiments on isolated colonic crypts. We conclude that K(V)QT1 is forming an important component of the basolateral cAMP-activated K+ conductance in the colonic epithelium and plays a crucial role in diseases like secretory diarrhea and cystic fibrosis.

El Adak Assidi Abdia ; Malkia Mala Ahia / Chikha Fatma El Ouargua, chant [acc. voc. et instr.]

[Traditions. Afrique du Nord. Maroc]

Libros de texto y aprendizaje en la escuela.

Con el interés de conocer a fondo el lenguaje presente en los libros de texto de Ciencias Naturales y Ciencias Sociales y de determinar su incidencia en los procesos de aprendizaje, se han observado varios grupos de estudiantes de secundaria de Barranquilla (Colombia), empleando el método de investigación etnográfica. Se analizan las reacciones observadas en los estudiantes ante el libro de texto y qué características del mismo suscitan esas reacciones, aspectos que pueden influir en el nivel de aprendizaje. En la obra se presentan algunas orientaciones para analizar el libro de texto y establecer la relación entre éste y el aprendizaje de los alumnos, proponiendo unas pautas para elaborar un cuestionario que permita evaluar el libro de texto.

Human security in Central Asia: can the EU help out? EUCAM Policy Brief No. 21, October 2011

The European Union is a security actor in Central Asia, although with less influence than other players. Russia and China have a much larger impact on Central Asian regimes’ security strategies. These limitations do not dispense with the need for the EU to provide a better security narrative, especially in light of its growing emphasis on human security, and to incorporate this into the current review of its strategy for the region. This policy brief will centre on the EU’s contribution to human security in Central Asia.