The main contribution to ESR spectra of lyophilized tissues of plant or animal origin usually is given by an anisotropic singlet, which is known to be caused at least in the majority of cases by the adsorption of an ascorbyl radical. Model systems have been investigated in order to discuss experimental parameters, which influence these spectra qualitatively and quantitatively.

Exposure of insulin-producing cells to elevated levels of the free fatty acid (FFA) palmitate results in the loss of β-cell function and induction of apoptosis. The induction of endoplasmic reticulum (ER) stress is one mechanism proposed to be responsible for the loss of β-cell viability in response to palmitate treatment; however, the pathways responsible for the induction of ER stress by palm...

The hypothesis that substrate availability can alter contractile function in reperfused myocardium after global ischemia was investigated in this study. Isolated rabbit hearts were placed in a dual tuned (31P/13C) NMR probe with a 9.4-T magnet and perfused with the following substrates given individually or in combination: 10 mM glucose, 2 mM palmitate, and 2.5 mM [3-13C]pyruvate. Glucose was t...

In the eye, hydrolysis of stored retinyl esters is catalyzed by retinyl ester hydrolase (REH) activities in retinal pigment epithelium (RPE) membranes. In the present study, biochemical analyses were conducted to determine the substrate specificity of these activities. Specific activities determined for hydrolysis of various retinol isomers of retinyl palmitate (9-cis-, 11-cis-, 13-cis-, and al...

Exposure to high fatty acids (FAs) induces whole body and skeletal muscle insulin resistance. The globular form of the adipokine, adiponectin (gAd), stimulates FA oxidation and improves insulin sensitivity; however, its ability to prevent lipid-induced insulin resistance in humans has not been tested. The purpose of this study was to determine 1) whether acute (4 h) exposure to 2 mM palmitate w...

Fatty acid-free albumin has been the standard carrier for intravenous infusion of fatty acids to study in vivo lipid metabolism. However, subjects can have adverse reactions to infusion of albumin. We sought an alternative to albumin as a carrier for intravenous infusion of fatty acids, using the pig as a model. Cyclodextrins are naturally occurring water-soluble molecules that can serve as car...

Determination of the BSA-palmitate high-affinity binding constant ( K a) traditionally relied on the heptane-water partitioning technique. We used this technique to calculate K a for the BSA-[3H]palmitate complex, to determine if K a was independent of protein concentration, and to determine if the unbound [3H]palmitate concentration is constant at different BSA concentrations using constant BS...

Since cytochrome c and acetylated cytochrome c disappear from the circulation with a half-life of 4 min, these proteins cannot be used for in vivo detection of superoxide radicals and related metabolites. To determine superoxide and other radicals in vivo, a cytochrome c derivative (SMAC) was synthesized by linking 1 mol of poly(styrene-co-maleic acid) butyl ester (SM) to cytochrome c, followed...

Ascorbyl free-radical reductase was purified 1143-fold with an overall yield of 9.9% from the cytosolic fraction of Pleurotus ostreatus. The native enzyme had a molecular mass of 127 kDa and SDS/PAGE revealed that the enzyme consists of two subunits, each with a molecular mass of 62 kDa. The enzyme utilized only NADH as an electron donor. The enzyme was highly specific for ascorbyl free radical...

BACKGROUND Saturated fatty acids are toxic to liver cells and are believed to play a central role in the pathogenesis of non-alcoholic steatohepatitis. In experimental steatohepatitis induced by feeding mice a methionine-choline-deficient (MCD) diet, the degree of liver damage is related to dietary sugar content, which drives de novo lipogenesis and promotes the hepatic accumulation of saturate...