Selenium is an essential element in human and animal metabolism integrated into the catalytic site of glutathione peroxidase (GPX1), an antioxidant enzyme that protects cells from damage caused by reactive oxygen species (ROS). Oxidative stress refers the imbalance between ROS and antioxidant defense systems. It generates alterations of DNA, proteins and lipid peroxidation.
View Article and Find Full Text PDFA HPLC coupled with molecular fluorescence (MF) spectrometry method for determination of thimerosal (THM, sodium ethylmercurythiosalicylate, C H HgNaO S), and derivatives is proposed. A sensitization of MF was provoked by UV irradiation of analytes in a home-made photoreactor that served as interface between the LC column and MF spectrometer. This method is applied to determination of THM, ethyl mercury, and thiosalicylic acid in samples of pharmaceutical industry effluents, and waters of La Carolina and Jáchal rivers situated in the center-west side of San Luis city and in the east of San Juan city (Middle West, Argentine) where the effluents are dumped.
View Article and Find Full Text PDFA new environmental friendly methodology based on fluorescent signal enhancement of rhodamine B dye is proposed for Pb(II) traces quantification using a preconcentration step based on the coacervation phenomenon. A cationic surfactant (cetyltrimethylammonium bromide, CTAB) and potassium iodine were chosen for this aim. The coacervate phase was collected on a filter paper disk and the solid surface fluorescence signal was determined in a spectrofluorometer.
View Article and Find Full Text PDFA procedure for the determination of traces of total tellurium (Te) in garlic (Allium sativa) is described that combines hydride generation atomic absorption spectrometry with preconcentration of the analyte by coprecipitation. The samples, each spiked with lanthanum nitrate (20 mg/L), are introduced into an Amberlite XAD-4 resin and mixed with ammonium buffer (pH 9.1).
View Article and Find Full Text PDFObjective: The present double blind-placebo controlled study was carried out to assess whether melatonin (3 mg p.o., fast release form) could be useful to reduce benzodiazepine dosage in old patients with minor sleep disturbance.
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