[Supraventricular tachycardia due to simultaneous conduction in the rapid and slow nodal pathways. Treatment by ablation of the slow pathway].

The authors report the case of a 70 year old woman with frequent attacks of supraventricular tachycardia resistant to antiarrhythmic therapy. The tachycardia was irregular with predominantly normal QRS complexes. Electrophysiological investigation showed dual conduction in the atrioventricular node and tachycardia was induced by atrial extrastimulus.

Water pathways across a reconstituted epithelial barrier formed by Caco-2 cells: effects of medium hypertonicity.

Caco-2 cells, originated in a human colonic cancer, are currently used as model systems to study transepithelial transports. To further characterize their water permeability properties, clone P1 Caco-2 cells were cultured on permeable supports. At confluence, the transepithelial net water movement (Jw), mannitol permeability (Ps), and electrical resistance (R) were simultaneously measured.

Aquaporin-CHIP-related protein in frog urinary bladder: localization by confocal microscopy.

Aquaporin CHIP, a 28 kDa channel forming protein, has been proposed to function as water channel in both erythrocyte and kidney proximal tubule. Recently, we have reported that in frog urinary bladder, a model of the kidney collecting tubule, polyclonal antibodies against human erythrocyte CHIP recognize and immunoprecipitate a 30 kDa protein from the epithelial cell homogenate. In the present work confocal fluorescence microscopy was used to determine the cellular and subcellular localization of CHIP28-like proteins in the urinary epithelium.

Activation of the vasopressin-sensitive water permeability pathway in the toad bladder by N-ethyl maleimide.

Vasopressin stimulates transepithelial water flow in the toad urinary bladder. We report here that N-ethyl maleimide (NEM) (0.1 mM) produces a similar increase in osmotic water flow when applied to the mucosal surface of the tissue.

Antidiuretic response in the urinary bladder of Xenopus laevis: presence of typical aggrephores and apical aggregates.

The urinary bladder of the aquatic toad Xenopus laevis is known to exhibit a low permeability to water and a poor sensitivity to antidiuretic hormone. In order to precise the characteristics and the specific cellular mechanisms of this reduced hydro-osmotic response we used a sensitive volumetric technique to monitor net water flow and studied the correlation between the antidiuretic hormone (ADH)-induced net water flow and the fine ultrastructural appearance of the urinary bladder epithelium. Transmural net water flow was entirely dependent on the osmotic gradient across the preparation and not on the hydrostatic pressure difference.