BACKGROUND It has long been suggested that reactive oxygen species (ROS) play a role in oxygen sensing via peripheral chemoreceptors, which would imply their involvement in chemoreflex activation and autonomic regulation of heart rate. We hypothesize that antioxidant affect neurogenic cardiovascular regulation through activation of chemoreflex which results in increased control of sympathetic m...

The role of superoxide anion (O2-) and nitric oxide (NO) in the host defense mechanism against Salmonella typhimurium (LT-2) was examined by focusing on xanthine oxidase (XO) as an O2(-)-generating system and on inducible NO synthase (iNOS). When ICR mice were infected with a 0.1 50% lethal dose (2 x 10(5) CFU) of S. typhimurium, bacterial growth in the liver reached a peak value 3 days after i...

The objective of this study was to examine the effect of reactive oxygen species (ROS) and cryopreservation on DNA fragmentation of equine spermatozoa. In experiment 1, equine spermatozoa were incubated (1 hour, 38 degrees C) according to the following treatments: 1) sperm alone; 2) sperm + xanthine (X, 0.3 mM)-xanthine oxidase (XO, 0.025 U/mL); 3) sperm + X (0.6 mM)-XO (0.05 U/mL); and 4) sper...

Let k 3 0 be arbitrary. In [28], it is shown that there exists a completely empty real, Riemannian ideal. We show that exp ( I ) < tanh (D) ∪ Λ (0P ) . It has long been known that XO is equal to fd,g [28]. We wish to extend the results of [25] to linear equations.

We describe strategies and tactics for detecting transiting planets, as learned from the experience of the XO Project. A key component is the web-enabled collaboration with a longitudinally-distributed Extended Team of dedicated volunteers operating small-aperture telescopes near their homes. We also quantify the (small) potential to discover transiting planets of M dwarfs from existing data su...

Exposure of red blood cells to oxygen radicals can induce hemoglobin damage and stimulate protein degradation, lipid peroxidation, and hemolysis. To determine if these events are linked, rabbit erythrocytes were incubated at 37 degrees C with various oxygen radical-generating systems and antioxidants. Protein degradation, measured by the production of free alanine, increased more than 11-fold i...

Milk xanthine oxidase (XO) has been prepared in a dehydrogenase form (XDH) by purifying the enzyme in the presence of 2.5 mM dithiothreitol. Unlike XO, which reacts rapidly only with oxygen and not with NAD, the XDH form of the enzyme reacts rapidly with NAD. XDH has a turnover number for the NAD-dependent conversion of xanthine to urate of 380 mol/min/mol at pH 7.5, 25 degrees C, with a Km = <...

OBJECTIVE To evaluate the inhibitory effect of Gnaphalium affine extracts on xanthine oxidase (XO) activity in vitro and to analyze the mechanism of this effect. METHODS In this in vitro study, Kinetic measurements were performed in 4 different inhibitor concentrations and 5 different xanthine concentrations (60, 100, 200, 300, 400 Μmol/L). Dixon and Lineweaver-Burk plot analysis were used to...

In this work we study the Positive Extension (PE) property and Hilbert’s 17th Problem for real analytic germs and sets. A real analytic germ Xo of Ro has the PE property if every positive semidefinite analytic function germ on Xo has a positive semidefinite analytic extension to Ro ; analogously one states the PE property for a global real analytic set X in an open set Ω of R. These PE properti...