BACKGROUND The tachycardia circuit in the fast-slow form of atrioventricular nodal reentrant tachycardia (FS-AVNRT) has not been convincingly defined. METHODS AND RESULTS To define the tachycardia circuit, single extrastimuli were delivered during FS-AVNRT to 9 intra-atrial sites in 12 patients: the His bundle (HB) site; the superior portion of the HB site (S-HB); 3 arbitrarily divided sites ...

Allochromatium vinosum polyhydroxyalkanoate synthase catalyzes formation of poly-(R)-3-hydroxybutyrate (PHB) from (R)-3-hydroxybutyryl-coenzyme A (HB-CoA). (R)-3-Hydroxybutyryl-N-acetylcysteamine (HB-NAC) is an alternative substrate for this synthase in vitro, with a turnover 1% that of HB-CoA. With HB-NAC, the molecular weight (M(w)) of PHB produced at substrate-to-enzyme ratios of 1500-15 000...

It is hypothesized that oxidative reactions of hemoglobin driven by reactive oxygen species in the vasculature lead to endothelial cell injury or death. Bovine aortic endothelial cells were incubated with diaspirin cross-linked hemoglobin (DBBF-Hb), developed as a hemoglobin-based oxygen carrier, and hydrogen peroxide (H(2)O(2)), generated by the glucose oxidase system. The low steady flux of H...

The relative position of the hydroxylic and the carboxylic group in the isomeric hydroxybenzoate (HB) anions is known to have a large impact on transport properties of this species. It also influences crucially the self-organisation of cationic surfactants. In this article a systematic investigation of aqueous solutions of the ortho, meta, and para isomers of the HB anion is presented. Molecula...

The functional properties of four glycosylated minor components of human hemolysate have been examined. In 0.1 M potassium phosphate buffer, pH 7 and 2O”C, the p50 values of Hb Al,,, Hb Alaz, Hb Al,, and Hb A, were 14,9.8,6.3, and 7.4 mm Hg, respectively, compared to 7.8 mm Hg for the major component, Hb Ao. The A log p&A pH (pH 7 to pH 8) was -0.5 for Hb A1 .1, Hb Alaz, and Hb A1, as compared ...

where H and L represent the hybrid Hb and ligand, respectively. O2 binding features of Kb M Saskatoon were similar to those of Hb M Milwaukee (Makino, N., Sugita, Y., and Nakamura, T. (1979) J. Biol. Chem. 254,2353-2357), although the rate constants of OZ dissociation were smaller for Hb M Saskatoon. In CO binding, considerable differences were observed between the two kinds of Hbs M in the pH ...