BACKGROUND Hepatitis B virus initiates a complicated cascade process leading to chronic hepatitis B, cirrhosis, and hepatocellular carcinoma. In inflammatory situations, myeloperoxidase is released in plasma and binds to apolipoprotein A-1 in high-density lipoproteins. This study aims to evaluate the level of plasma myeloperoxidase as well as the pattern of plasma proteins in patients with chro...

The morbidity burden associated with anti-neutrophil cytoplasmic autoantibody-associated vasculitis is increasing, and many novel biological therapies are now entering the drug development pipeline. There is thus an urgent need to develop a representative animal model to facilitate testing of these agents. We previously examined the effect of antineutrophil cytoplasmic autoantibody on leukocyte...

Myeloperoxidase is a heme enzyme of neutrophils that uses hydrogen peroxide to oxidize chloride to hypochlorous acid. Recently, it has been shown to catalyze nitration of tyrosine. In this study we have investigated the mechanism by which it oxidizes nitrite and promotes nitration of tyrosyl residues. Nitrite was found to be a poor substrate for myeloperoxidase but an excellent inhibitor of its...

OBJECTIVE Apolipoprotein A-I (apoAI) acts as an ABCA1-dependent acceptor of cellular phospholipids and cholesterol during the biogenesis of HDL, but this activity is susceptible to oxidative inactivation by myeloperoxidase. We tried to determine which residues mediated this inactivation and create an oxidant-resistant apoAI variant. METHODS AND RESULTS Mass spectrometry detected the presence ...

Subjects with neutrophil myeloperoxidase (MPO) deficiency have been rarely reported. In part this may be due to the lack of a simple screening technique that would detect them. With the routine use of a cytochemical leukocyte differential counter that employs MPO stains, over a 40-mo a period 8 unrelated probands with partial MPO-deficiency and one with complete deficiency were identified. Fami...

The functional properties of granulocytes in a diabetic patient deficient in myeloperoxidase (MPO) were compared with those of granulocytes in healthy subjects. The granulocytes of this patient had normal phagocytic activity. The microbicidal activity of the granulocytes was partially diminished with regard to Staphylococcus aureus and was almost nil with regard to Candida albicans. Fungicidal ...

Hansen KE, et al. Assay variation confounds the diagnosis of hypovitaminosis D: a call for standardization. J Clin Endocrinol Metab 2004;89: 3152–7. 4. Souberbielle JC, Fayol V, Sault C, Lawson-Body E, Kahan A, Cormier C. Assay-specific decision limits for two new automated parathyroid hormone and 25-hydroxyvitamin D assays. Clin Chem 2005;51:395–400. 5. Singh RJ, Taylor RL, Reddy GS, Hollis BW...