The action of endothelin in small intestinal resistance vessels of the guinea pig was studied by examining submucosal arteriole vasoactivity in vitro and electrical properties of mesenteric arteriole smooth muscle cells. Endothelin-1 (ET-1) constricted submucosal arterioles with a half-maximal effective concentration of 170 pM. ET-3 caused detectable constriction with a minimum of 20 nM. The ET...

INTRODUCTION It is believed that an exaggerated blood pressure response (EBPR) to exercise stress test is associated with a higher risk of cardiovascular events. It is also assumed that QT dispersion (QT-d), which was originally proposed to measure the spatial dispersion of ventricular recovery times, may have a relationship to cardiovascular events. The objective of this study was to examine t...

Iberiotoxin (IbTX) is a remarkably selective alpha-K toxin peptide (alpha-KTx) inhibitor of the maxi-K channel. In contrast, the highly homologous charybdotoxin inhibits both the maxi-K and K(V)1.3 channels with similar high affinity. The present study investigates the molecular basis for this specificity through mutagenesis of IbTX. The interactions of mutated peptides with maxi-K and K(V)1.3 ...

Antibiotic aerosol treatment is successful in treating Pseudomonas infection in some patients with cystic fibrosis, but the amount of drug reaching the lungs is unknown. The deposition patterns of carbenicillin aerosols delivered from two commercially available nebuliser systems (the Turret nebuliser plus Maxi compressor and the Inspiron nebuliser plus Traveller compressor) have been compared i...

The cell regulatory volume decrease (RVD) response triggered by hypotonic solutions is mainly achieved by the coordinated activity of Cl- and K+ channels. We now describe the molecular nature of the K(+) channels involved in the RVD response of the human bronchial epithelial (HBE) cell line 16HBE14o-. These cells, under isotonic conditions, present a K+ current consistent with the activity of m...

Ferritins are spherical, cage-like proteins with nanocavities formed by multiple polypeptide subunits (four-helix bundles) that manage iron/oxygen chemistry. Catalytic coupling yields diferric oxo/hydroxo complexes at ferroxidase sites in maxi-ferritin subunits (24 subunits, 480 kDa; plants, animals, microorganisms). Oxidation occurs at the cavity surface of mini-ferritins/Dps proteins (12 subu...

Belief Revision is a ubiquitous process underlying many forms of intelligent behaviour. The AGM paradigm is a powerful framework for modeling and implementing belief revision systems based on the principle of Minimal Change; it provides a rich and rigorous foundation for computer-based belief revision architectures. Maxi-adjustment is a belief revision strategy for theory bases that can be impl...

By incorporating plasma membrane vesicles into planar lipid bilayers, we previously characterized a family of four types of Ca(2+)-activated K+ channels from rat brain (Reinhart et al., 1989). Two of these are "large-conductance" or "maxi"-K+ channels, which differ in their gating kinetics and toxin sensitivity and are henceforth referred to as "type 1" and "type 2" channels. Here we show that ...

We investigated the regulation of the Ca2+-activated K+(maxi-K+) channel by angiotensin II (ANG II) and its synthetic analog, [Lys2]ANG II, in freshly dispersed intestinal myocytes. We identified a maxi-K+ channel population in the inside-out patch configuration on the basis of its conductance (257 ± 4 pS in symmetrical 150 mM KCl solution), voltage and Ca2+ dependence of channel opening, low N...