Quantitative analysis of parasympathetic innervation of the porcine heart.

Background: Parasympathetic control of the heart is an important component in the regulation of normal cardiac function. However, the anatomic course of parasympathetic innervation of the heart is unclear.

Objective: The purpose of this study was to apply a gross parasympathetic nerve stain technique to reveal the details of the morphology of the cardiac parasympathetic nervous system.

High-resolution electrical mapping of depolarization and repolarization alternans in an ischemic dog model.

Cardiac electrical alternans have been associated with spontaneous ventricular arrhythmias during myocardial ischemia. The study aims were to use a new algorithm to measure depolarization and repolarization alternans from epicardial electrograms in an ischemia model and to evaluate which features are predictive of ventricular fibrillation (VF). The left anterior descending coronary artery was occluded in 21 dogs, of which 6 developed spontaneous VF.

Neural substrate for atrial fibrillation: implications for targeted parasympathetic blockade in the posterior left atrium.

The parasympathetic (P) nervous system is thought to contribute significantly to focal atrial fibrillation (AF). Thus we hypothesized that P nerve fibers [and related muscarinic (M(2)) receptors] are preferentially located in the posterior left atrium (PLA) and that selective cholinergic blockade in the PLA can be successfully performed to alter vagal AF substrate. The PLA, pulmonary veins (PVs), and left atrial appendage (LAA) from six dogs were immunostained for sympathetic (S) nerves, P nerves, and M(2) receptors.

Frequency gradients during two different forms of fibrillation in the canine atria.

Background: Atrial fibrillation (AF) is thought to be sustained by multiple reentrant wavelets or firing foci.

Objective: The aim of this study was to compare the spectral domain characteristics in the left atrium (LA) and right atrium (RA) in two different models of AF.

Methods: Rectangular 8 x 14 electrode arrays were placed on the LA and RA of 14 anesthetized dogs.

The ligament of Marshall as a parasympathetic conduit.

The objective of the study was to investigate the morphology, distribution, and electrophysiological profile of the autonomic fibers that innervate the ligament of Marshall (LOM). Gross anatomical dissections were performed in 10 dogs. Sections of the left vagus nerve, left stellate ganglion, and the LOM were immunostained to identify adrenergic and cholinergic nerves.

Unique autonomic profile of the pulmonary veins and posterior left atrium.

Objectives: The purpose of this study was to investigate the electrophysiologic profile of the pulmonary veins (PVs) and left atrium (LA) in response to autonomic manipulation.

Background: The parasympathetic innervation of the PVs and posterior left atrium (PLA) is thought to contribute to focal atrial fibrillation (AF). We hypothesized that autonomic effects would be more prominent in these regions.

Model of Staphylococcus aureus central venous catheter-associated infection in rats.

Background And Purpose: Staphylococcus aureus is an important cause of intravascular catheter-associated bacteremia. We developed a rat central venous catheter (CVC)-associated infection model to study pathogenesis and treatment.

Methods: A silastic lumen-within-lumen catheter and rodent-restraint jacket were designed.

Characterization of the relationship between polysaccharide intercellular adhesin and hemagglutination in Staphylococcus epidermidis.

To determine whether a relationship exists between biofilm formation and hemagglutination in Staphylococcus epidermidis, 20 skin isolates and 19 prosthetic valve endocarditis isolates were characterized for biofilm formation, hemagglutination, and the presence of a 357-bp polymerase chain reaction product within icaA. A strong association existed between biofilm formation, which has been linked to strains that produce polysaccharide intercellular adhesin (PIA), and hemagglutination. Strains that produced biofilm were significantly (P<.

Characterization of Staphylococcus epidermidis polysaccharide intercellular adhesin/hemagglutinin in the pathogenesis of intravascular catheter-associated infection in a rat model.

Biofilm production is thought to be a crucial factor in the ability of Staphylococcus epidermidis to produce a biomaterial-based infection. A rat central venous catheter (CVC)-associated infection model was used to assess the importance of biofilm production, mediated by polysaccharide intercellular adhesin/hemagglutinin (PIA/HA), in the pathogenesis of intravascular catheter-associated infection. PIA/HA-positive S.

Characterization of the importance of polysaccharide intercellular adhesin/hemagglutinin of Staphylococcus epidermidis in the pathogenesis of biomaterial-based infection in a mouse foreign body infection model.

The production of biofilm is thought to be crucial in the pathogenesis of prosthetic-device infections caused by Staphylococcus epidermidis. An experimental animal model was used to assess the importance of biofilm production, which is mediated by polysaccharide intercellular adhesin/hemagglutinin (PIA/HA), in the pathogenesis of a biomaterial-based infection. Mice were inoculated along the length of a subcutaneously implanted intravenous catheter with either wild-type S.

Cooperative ligand binding by bovine phenol sulfotransferase.

Although several phenol sulfotransferases (PSTs) that metabolize hormones and xenobiotics have been purified and examined by steady state kinetic methods, little is known about ligand binding and subunit interactions in these enzymes. Inhibition of a purified recombinant homodimeric bovine PST by 2,6-dichloro-4-nitrophenol (DCNP) and pentachlorophenol (PCP) displayed very sharp titration curves that required modeling with Hill equations with slope factors of 2 and 3, respectively. This observation suggested positive cooperative ligand binding during catalytic turnover.

Isolation and characterization of a bovine gene encoding phenol sulfotransferase.

Phenol sulfotransferases (PST) esterify hydroxylated aromatic compounds with sulfate, and therefore play a role in the metabolism of xenobiotics. In this investigation, a bovine PST gene of 2372 bp was amplified from genomic DNA. Sequence overlap with the cognate cDNA revealed seven exons, with all introns containing GT/AG splicing donor/acceptor site.

Phenol sulfotransferase activities and localization in human nasal polyp epithelium.

Nasal polyp epithelia, which exhibit a wide variation in epithelial cell morphologies, were tested for phenol sulfotransferase (PST) enzymes. Immunohistology revealed little or no detectable PST antigen in normal ciliated pseudostratified epithelia or in simple squamous metaplastic epithelia; however, intense expression was observed in regions of non-ciliated epithelial cell hyperplasia and in squamous epithelial cells overlying such hyperplastic sites. Western blots confirmed the presence of both P-PST (32 kDa) and M-PST (34 kDa) in the tissue extracts.

Pharmacology of selective and non-selective metabotropic glutamate receptor agonists at L-AP4 receptors in retinal ON bipolar cells.

Retinal ON bipolar cells possess metabotropic glutamate receptors (mGluRs) which are sensitive to L-2-amino-4-phosphonobutyric acid (L-AP4). Recent studies suggest there are multiple subtypes of L-AP4 receptors. In order to provide a more complete description of the pharmacology of the retinal L-AP4 receptor, we examined the actions of a number of compounds which are active at L-AP4 receptors and other mGluRs.