ABSTRACT
An alternative metric to account for particulate matter (PM) composition-based toxicity is the ability of PM-species to generate reactive oxygen species (ROS) and deplete antioxidants, the so-called oxidative potential (OP). Acellular OP assays are the most used worldwide, mainly those based on ascorbic acid (AA) and dithiothreitol (DTT) depletion; OP values are calculated from AA/DTT concentration over time kinetic curves. Since a great variability in OP-DTT and OP-AA values can be found in the literature, the understanding of those factors affecting the kinetic rate of AA and DTT oxidation in the presence of PM-bound species will improve the interpretation of OP values. In this work, a kinetic study of the oxidation rate of AA and DTT driven by species usually found in PM (transition metals and naphthoquinone (NQ)) was carried out. In particular, the influence of the concentration of Cu(II), Fe(II), Fe(III), Mn(II), Mn(III), and 1,4-NQ, and the type of fluid used in the assay (phosphate buffer (PB), phosphate buffer saline (PBS) and artificial lysosomal fluid (ALF)) is analysed and discussed. The reaction orders with respect to the AA/DTT and the active compound, and the kinetic rate constants were also determined. The results show great variability in OP values among the studied species depending on the fluid used; the OP values were mostly higher in PB0.05 M, followed by PBS1x and ALF. Moreover, different species concentration-responses for OP-DTT/OP-AA were obtained. These differences were explained by the different reaction orders and kinetic rate constants obtained for each active compound in each fluid.
Subject(s)
Ascorbic Acid , Copper , Dithiothreitol , Iron , Manganese , Naphthoquinones , Oxidation-Reduction , Kinetics , Ascorbic Acid/chemistry , Naphthoquinones/chemistry , Dithiothreitol/chemistry , Iron/chemistry , Copper/chemistry , Manganese/chemistry , Particulate Matter/chemistry , Particulate Matter/analysis , Antioxidants/chemistry , Reactive Oxygen Species/metabolism , Reactive Oxygen Species/chemistryABSTRACT
Se presenta el caso de un recién nacido con ectasia congénita de las arterias coronarias. Se repasan la frecuencia, la etiología, la clínica y la evolución de esta entidad, así como su posible relación con el hiperinsulinismo que también presentaba el paciente (AU)
The case of a newborn with congenital coronary artery ectasia is presented. Frequency, etiology, and clinical evolution of this entity and its possible relationship with hyperinsulinism also presented the patient is reviewed (AU)
