Native Human Myeloperoxidase

cis-2-Methyl-4-propyl-1,3-oxathiane (cis-2-MPO) was recently identified in wine and proposed to arise from the reaction of 3-sulfanylhexan-1-ol (3-SH) and acetaldehyde. However, the evolution profile of cis-2-MPO during alcoholic fermentation (AF) and storage and its relationship with varietal thiols and acetaldehyde production were unknown. These aspects were investigated by fermenting Sauvignon blanc juice with J7 and/or VIN13 yeast strains and assessing the stability of cis-2-MPO during wine storage. Moderate to strong Pearson correlations verified similar evolution trends between acetaldehyde, 3-sulfanylhexyl acetate, and cis-2-MPO, with initial increases and a peak during the early to middle stages of AF before consecutive decreases until the end. Contrarily, 3-SH correlated moderately only at the end of AF. A consistent decrease observed for cis-2-MPO when spiked into Sauvignon blanc wine and assessed during 1-year storage revealed its general instability, but acetaldehyde addition (100 mg/L), pH 3.0, and storage at 4 degrees C all appeared to retain cis-2-MPO. These results have implications for wine aroma and the potential for cis-2-MPO to act as a sink (or source) for 3-SH in wine over time.

The cornerstone of the laboratory diagnostics of small vessel vasculitis is the detection of antineutrophil cytoplasmic antibodies (ANCA). The current international consensus recommendations suggest that proteinase 3 (PR3) and myeloperoxidase (MPO) ANCA immunoassays should be used as a first-line test if there is a justified suspicion of ANCA-associated vasculitis (AAV). A second method is only recommendable when the immunoassay shows a negative or borderline result. The precise identification of all patients with active AAV and avoidance of misdiagnoses due to false positive ANCA measurements is achieved when the ANCA determination is limited to defined clinical situations, which are indicative for AAV. There is increasing evidence that the specificity of ANCA to define homogeneous groups of patients could be better with respect to the prognosis than the clinical subtype.