The effect of long-running severe selenium-deficiency on the amount of iron and zinc in the organs of rats.

The amounts of selenium (Se), iron (Fe), and zinc (Zn) in the liver, kidney, and spleen as a function of age of rats measured using instrumental neutron activation analysis were compared between Se-deficient (SeD) rats and normal rats. The SeD model rats can live for more than 50 weeks. The effect of Se-deficinecy in rats might be weak, compared to the marked malfunction of GSH-Px.

Detection of free radical reactions in an aqueous sample induced by low linear-energy-transfer irradiation.

Quantitative detection of free radical reactions induced by low linear-energy-transfer (LET) irradiation in an aqueous solution was attempted using nitroxyl radicals. The stability and reactivity of reaction mixtures containing a nitroxyl radical and a hydrogen donor, i.e.

Intracellular and extracellular redox environments surrounding redox-sensitive contrast agents under oxidative Atmosphere.

In vivo redox reactions of nitroxyl contrast agents in bile and blood under an oxidative atmosphere were investigated using normal healthy Wistar rats. Differences in intracellular and extracellular volumes in redox environments are discussed. Pharmacokinetic profiles of two nitroxyl contrast agents, 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-N-oxyl (carbamoyl-PROXYL), 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPOL), in bile and blood were monitored by an electron paramagnetic resonance spectrometer when the rat was breathing 100% O(2) or was subcutaneously administrated 0.

Competition of nitroxyl contrast agents as an in vivo tissue redox probe: comparison of pharmacokinetics by the bile flow monitoring (BFM) and blood circulating monitoring (BCM) methods using X-band EPR and simulation of decay profiles.

Nitroxyl radicals used as tissue redox-sensitive contrast agents in electron paramagnetic resonance (EPR) and/or NMR imaging should satisfy the following two conditions: 1) the molecules disperse into tissues rapidly, and 2) paramagnetic loss occurs by simple reduction of the radical. The pharmacokinetic trends of several nitroxyl contrast agents were compared with the results obtained by bile flow monitoring (BFM) and blood circulation monitoring (BCM) methods using X-band EPR. The nitroxyl radicals (TEMPO, TEMPONE (oxo-TEMPO), and amino-TEMPO) showed additional EPR signals in the bile that were attributed to metabolites formed during transport from blood to bile through the liver.

Importance of volume limitation for tissue redox status measurements using nitroxyl contrast agents: a comparison of X-band EPR bile flow monitoring (BFM) method and 300 MHz in vivo EPR measurement.

Methods proposed for in vivo redox status estimation, X-band (9.4 GHz) electron paramagnetic resonance (EPR) bile flow monitoring (BFM) and 300 MHz in vivo EPR measurement, were compared. The spin probe 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (carbamoyl-PROXYL) was utilized for both methods, due to its suitable lipophilicity.

Electron paramagnetic resonance decay constant and oxidative stresses in liver microsomes of the selenium-deficient rat.

The free radical-reducing activity and the membrane fluidity of liver microsomes from selenium-deficient (SeD) rats were examined by means of electron paramagnetic resonance (EPR) spin label method using nitroxyl-labeled stearic acids. Our findings show that the membrane fluidity and lipid peroxidation levels in SeD rat liver microsome were relatively unchanged compared with normal rat. In contrast, SeD caused the induction of liver microsomal cytochrome P-450 activity.

Correlation between ketone body level in selenium-deficient rats and oxidative damages.

The age dependence of ketone body levels (KBLs) and oxidative damages in selenium-deficient (SeD) and normal rats were compared. The feeding SeD diets gave ketogenesis and higher KBLs especially in younger rats. However, KBLs in SeD rats seemed to decrease with their age.

Estimation of free radical formation by beta-ray irradiation in rat liver.

In vivo free radical reactions in rat liver as a result of exposure to low-dose beta-radiation was evaluated with electron paramagnetic resonance (EPR) spectroscopy by monitoring the reduction of the nitroxyl spin probe after intravenous administration. The EPR signal intensity of a nitroxyl probe as a function of time in bile flow was monitored by cannulating the bile duct through the cavity of an X-band EPR spectrometer. The results show that the rate of nitroxyl signal loss was higher in rats whose livers were exposed to beta-rays compared to unexposed rats.

Effect of hydrogen peroxide in redox status estimation using nitroxyl spin probe.

A procedure for estimating in vivo redox status using EPR and a hydrogen peroxide (H(2)O(2))-dependent spin probe method is described. The mechanism of decreasing spin clearance in the selenium-deficient (SeD) rat is discussed. The in vivo decay constant of the nitroxyl spin probe in the liver region of SeD rats appeared to be slightly lower that of the selenium-adequate control (SeC) group, and was significantly smaller than that of normal rats.