Search results for "liquid"
showing 10 items of 4351 documents
Magnetic molecularly imprinted polymers for the selective determination of cocaine by ion mobility spectrometry
2018
Abstract Magnetic molecularly imprinted polymers (MMIPs) were prepared for cocaine recognition by bulk polymerization in the presence of magnetic nanoparticles (MNPs). Two reagents (polyethylene glycol (PEG) and 3-(trimethoxysilyl)propyl methacrylate (V)) were used for MNPs modification. MMIPs were characterized and compared in terms of loading capacity, reusability, accuracy and precision for the extraction of cocaine from saliva samples. It was observed that V-MMIPs gave higher physical stability than PEG-MMIPs. Thus, V-MMIP were used for the analysis of cocaine users saliva. The developed procedure based on ion mobility spectrometry (IMS) provided limits of detection and quantification o…
A comprehensive untargeted metabonomic analysis of human steatotic liver tissue by RP and HILIC chromatography coupled to mass spectrometry reveals i…
2011
Steatosis, or excessive accumulation of lipids in the liver, is a generally accepted previous step to the development of more severe conditions like nonalcoholic steatohepatitis, fibrosis, and cirrhosis. We aimed, to characterize the metabolic profile that defines simple steatosis in human tissue and to identify potential disturbances in the hepatic metabolism that could favor the switch to progressive liver damage. A total of 46 samples, 23 from steatotic and 23 from nonsteatotic human livers, were analyzed following a holistic LC-MS-based metabonomic analysis that combines RP and HILIC chromatographic separations. Multivariate statistical data analysis satisfactorily classified samples an…
Inhibition of antidepressant demethylation and hydroxylation by fluvoxamine in depressed patients.
1993
Bidirectional drug interactions between fluvoxamine and classical antidepressants were studied in depressed patients. A column switching technique combined with high performance liquid chromatography (HPLC) enabled automated analyses of plasma for simultaneous determination of fluvoxamine, tricyclic and tetracyclic antidepressants and demethylated and major hydroxylated metabolites in a single HPLC run. The measurements revealed that fluvoxamine inhibited N-demethylation of imipramine, clomipramine, amitriptyline and maprotiline whereas interferences with hydroxylation reactions were restricted to aromatic 8-hydroxylation of clomipramine. In patients under fluvoxamine monotherapy before com…
Malondialdehyde in early phase of acute pancreatitis
2011
Aims: to assess oxidative stress in acute pancreatitis, its evolution over time and its relationship with the severity of the disease. Methods: during a two-year period, patients with acute pancreatitis with less than 24 hours of pain were evaluated. Serum was obtained the first, second and fourth day from admittance, if complications were detected, and after recovery. Malondialdehyde was determined by high performance liquid chromatography. Twenty healthy volunteers constituted the control group. Malondialdehyde between groups was compared with Mann-Whitney and Kruskal-Wallis tests; malondialdehyde evolution was studied with Wilcoxon test. Results: one hundred and sixty-nine patients were …
Development of a Rapid LC-MS/MS Method for the Determination of Emerging Fusarium mycotoxins Enniatins and Beauvericin in Human Biological Fluids
2015
A novel method for the simultaneous determination of enniatins A, A1, B and B1 and beauvericin, both in human urine and plasma samples, was developed and validated. The method consisted of a simple and easy pretreatment, specific for each matrix, followed by solid phase extraction (SPE) and detection by high performance liquid chromatography-tandem mass spectrometry with an electrospray ion source. The optimized SPE method was performed on graphitized carbon black cartridges after suitable dilution of the extracts, which allowed high mycotoxin absolute recoveries (76%–103%) and the removal of the major interferences from the matrix. The method was extensively evaluated for plasma and urine …
Urinary levels of enniatin B and its phase I metabolites: First human pilot biomonitoring study
2018
Abstract Enniatins (Enns) are mycotoxins produced by Fusarium spp. and are widely distributed contaminants of cereals and derivate products. Among the different identified enniatins, Enn B is the most relevant analogue in cereals in Europe. Therefore, the aim of this study was to investigate for the first time the occurrence of Enn B and Enn B phase I metabolites in 300 human urine samples throughout an ultrahigh-performance liquid chromatography-high resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) methodology. Three different sample preparation procedures were evaluated and salting-out liquid-liquid extraction showed satisfactory validation results. Enn B was quantified in 83.7% of sa…
In vivoprooxidant state in Werner syndrome (WS): Results from three WS patients and two WS heterozygotes
2005
The hypothesis was tested that Werner syndrome (WS) phenotype might be associated with an in vivo prooxidant state. A set of redox-related endpoints were measured in three WS patients, two of their parents, and 99 controls within a study of some cancer-prone and/or ageing-related genetic disorders. The following analytes were measured: (a) leukocyte 8-hydroxy-2'-deoxyguanosine; (b) glutathione from whole blood, and (c) plasma levels of glyoxal, methylglyoxal, 8-isoprostane, and some plasma antioxidants (uric acid, ascorbic acid, alpha- and gamma-tocopherol). Leukocyte 8-hydroxy-2'-deoxyguanosine levels showed a significant increase in the 3 WS patients vs. 85 controls (p<10(-7)). The disulf…
Interaction between fascicle and tendinous tissues in short-contact stretch-shortening cycle exercise with varying eccentric intensities
2005
The interaction between fascicle and tendinous tissues (TT) in short-contact drop jumps (DJ) with three different drop heights [low (Low), optimal (OP), and high (High)] was examined with 11 subjects. The ground reaction force (F z) and ankle and knee joint angles were measured together with real-time ultrasonography (fascicle length) and electromyographic activities of the medial gastrocnemius (MG) and vastus lateralis (VL) muscles during the movement. With increasing drop height, the braking force and flight time increased from Low to OP ( P < 0.05). In High, the braking force increased but the flight time decreased compared with OP ( P < 0.05). During contact of Low and OP conditi…
Pharmacokinetics and bioavailability of benperidol in schizophrenic patients after intravenous and two different kinds of oral application
1994
Pharmacokinetics and bioavailability of benperidol were determined in 13 schizophrenic patients after acute administration of 6 mg benperidol as an intravenous (i.v.) bolus injection, orally as liquid, and orally as tablets using a partially randomized cross-over design. Drug plasma levels were determined by high performance liquid chromatography with electrochemical detection and subjected to model independent pharmacokinetic analyses. After i.v. dosing the geometric means (mean-g) were 3.2 min for the distribution half-life, 5.80 h for the elimination half-life (t1/2 beta), 4.21 l/kg for the distribution volume, 7.50 h for the mean residence time (MRT), and 0.50 l/(h*kg) for the clearance…
Postmortem distribution of dihydrocodeine and metabolites in a fatal case of dihydrocodeine intoxication.
1998
A report of a fatal dihydrocodeine ingestion under substitution therapy is given. Quantitation of dihydrocodeine, dihydromorphine, N-nordihydrocodeine, dihydrocodeine-6-, dihydromorphine-6- and dihydromorphine-3-glucuronide was performed simultaneously after solid-phase extraction prior to HPLC analysis, and the analytes were detected using their native fluorescence. Postmortem concentrations of blood samples from different sampling sites as well as from liver, kidney and cerebrum are reported. A hair sample was investigated to prove long-term use of the substitute drug. Site-to-site differences of the analytes from blood samples were very small. The partition behavior of the opioid glucuro…