Debbie J Mustacich

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The mammalian thioredoxin reductases (TrxRs) are a family of selenium-containing pyridine nucleotide-disulphide oxidoreductases with mechanistic and sequence identity, including a conserved -Cys-Val-Asn-Val-Gly-Cys- redox catalytic site, to glutathione reductases. TrxRs catalyse the NADPH-dependent reduction of the redox protein thioredoxin (Trx), as well(More)
The thioredoxins are ubiquitous proteins containing a conserved -Trp-Cys-Gly-Pro-Cys-Lys- redox catalytic site. Mammalian thioredoxin family members include thioredoxin-1 (Trx1), mitochondrial thioredoxin-2 (Trx2), and a larger thioredoxin-like protein, p32TrxL. Thioredoxin is reduced by NADPH and thioredoxin reductase and, in turn reduces oxidized cysteine(More)
The term vitamin E is used to describe eight lipophilic, naturally occurring compounds that include four tocopherols and four tocotrienols designated as alpha-, beta-, gamma-, and delta-. The most well-known function of vitamin E is that of a chain-breaking antioxidant that prevents the cyclic propagation of lipid peroxidation. Despite its antioxidant(More)
PURPOSE The effects of vitamin E supplementation on the cholesterol levels of hypercholesterolemic patients receiving statin therapy were studied. METHODS In this prospective, single-blind, placebo-controlled, randomized trial, patients who were currently taking either lovastatin or simvastatin for a primary diagnosis of hypercholesterolemia were given(More)
Hepatic proteins involved in xenobiotic pathways (Phases I, II and III) are responsible for the metabolism and disposition of endogenous and exogenous compounds including dietary phytochemicals. To test the hypothesis that elevated alpha-tocopherol intakes alter gene expression of hepatic xenobiotic pathways, mice were fed diets supplemented with either(More)
SCOPE The mechanism for increased bleeding and decreased vitamin K status accompanying vitamin E supplementation is unknown. We hypothesized that elevated hepatic α-tocopherol (α-T) concentrations may stimulate vitamin K metabolism and excretion. Furthermore, α-T may interfere with the side chain removal of phylloquinone (PK) to form menadione (MN) as an(More)
Approximately 40% of Americans take dietary supplements, including vitamin E (alpha-tocopherol). Unlike other fat-soluble vitamins, alpha-tocopherol is not accumulated to toxic levels. Rather tissue levels are tightly regulated, in part via increased hepatic metabolism and excretion that could, theoretically, alter metabolism of drugs, environmental toxins,(More)
The mechanism by which alpha-tocopherol (alpha-T) is secreted into the bile is not known; however, we have previously demonstrated that treatment with piperonyl butoxide (PIP, 1 g/kg) results in increased biliary output of both alpha-T and phosphatidylcholine within 3 h of ip injection in rats and that the biliary output of both substances was prevented by(More)
alpha-Tocopherol, a lipid-soluble chain-breaking antioxidant, is important in the protection of biologic membranes and is transported in the body in association with lipids. It has been estimated that the liver contains up to 29% of the alpha-tocopherol stores of the body. Piperonyl butoxide (PIP) is a widely used synthetic methylenedioxyphenyl insecticide(More)
To test the hypothesis that supra-elevated hepatic alpha-tocopherol concentrations would up-regulate mechanisms that result in increased hepatic alpha-tocopherol metabolism and excretion, rats received daily subcutaneous alpha-tocopherol injections (10 mg/100 g body wt) and then were sacrificed on Day 0 or 12 h following their previous injection on Days 3,(More)