53 research outputs found
Biochemical analysis of respiratory function in cybrid cell lines harbouring mitochondrial DNA mutations
Determination of free DOPA and 3-O-methyl-DOPA in human plasma by high-performance liquid chromatography with electrochemical detection.
A procedure was devised for the determination of the unconjugated non-protein-bound fraction of 3,4-dihydroxyphenylalanine (DOPA) and 3-O-methyl-DOPA (3-OMD) in plasma using a reversed-phase liquid chromatographic system coupled with electrochemical detection. Sample preparation involves rapid isolation of the unbound drugs from the drug-protein complex by ultrafiltration through a membrane with a molecular weight cut-off of 10 000 dalton. One chromatographic run requires less than 10 min. The relative standard deviation is < 3% for the within-assay imprecision and < 4% for the between-assay imprecision. The detection limits for DOPA and 3-OMD are 0.2 and 1.3 ng/ml, respectively
Determination of free 3-methoxy-4-hydroxyphenylethyleneglycol in plasma and in cerebrospinal fluid by liquid chromatography with coulometric detection.
Pancreatic amylase in serum for differential diagnosis of acute pancreatitis and acute abdominal diseases
Altered oxidative stress in healthy old subjects.
To understand the magnitude of oxidative phenomena during senescence, we evaluated, as antioxidant, the activity of glutathione peroxidase (GSH-Px) in erythrocytes and plasma uric acid (UA) levels together with the malondialdehyde (MDA) levels in plasma, as an index of lipid peroxidation, in 46 apparently healthy elderly subjects (87\ub16 years old; mean\ub1SD), and 49 young subjects (29\ub14 years old). The elderly subjects had lower erythrocyte GSH-Px activity (15.7\ub14.8 vs 20.2\ub17.0 U/g Hb, p<O.001; mean\ub1SD) and plasma UA levels (192\ub146 vs 240\ub154 mmol/L, p<0.001); but higher MDA levels (5.3\ub10.8 vs 4.1\ub10.8 mmol/L, p<0.001) than the young subjects. Of additional in terest was the finding of a positive correlation between age and erythrocyte GSH-Px activity (r=0.74, p<0.001), and a negative correlation between age and plasma MDA levels (r=-0.83, p<0.001) in the elderly group. Although erythrocyte GSH-Px activity was significantly less in the elderly than in the young group, the oldest subjects showed the greatest erythrocyte GSH-Px activity and had lower MDA levels
Determination of illicit drugs and related substances by high-performance liquid chromatography with an electrochemical coulometric-array detector.
A general method for the simultaneous determination of fifteen common drugs (6-acetylmorphine, 3,4-methylenedioxymetamphetamine, buprenorphin, cocaine, codeine, dihydrocodeine, ethylmorphine, heroin, hydrocodone, lidocaine, methadone, morphine, naloxone, procaine and thebaine) was developed using reversed-phase HPLC and electrochemical detection. The separation of the drugs was achieved by using as the mobile phase 20 mM monobasic sodium phosphate-acetonitrile (90:10) with a gradient to 50% of the organic modifier, on a silica based C18 column (150 x 4.6 mm I.D.) of 3 \u3bcm particle size and by the selectivity supplied by an array of eight coulometric electrodes at increasing potential. It was possible to identify and to determine fifteen different drugs in the same chromatographic run in 50 min. The method was tentatively applied to the determination of drugs in extracts of human hair
Determination of illicit drugs and related substances by high-performance liquid chromatography with an electrochemical coulometric-array detector.
- …