Search results for "MASS SPECTROMETRY"
showing 10 items of 2544 documents
Mass spectroscopic analysis of excimer laser ablated material from human corneal tissue.
1988
The clinical feasibility of photorefractive keratectomy depends on the surface structure of the ablated cornea. Two factors that influence the remodeled surface are the homogeneity of the energy distribution and the properties of the laser source (energy and wavelength). Currently, the homogeneity of the beam is difficult to control. The second factor, laser source properties, was the focus of this study. We investigated the effect of laser wavelength and energy by analyzing the reaction products of photoablation. We monitored the fragments produced by UV-laser ablation of human corneas using mass spectroscopy in the range of 0 to 100 atomic mass units. At 248 nm (KrF), average photon energ…
Oxyphytosterols are present in plasma of healthy human subjects
2004
The oxidised derivatives of phytosterols (oxyphytosterols) were identified in plasma samples from thirteen healthy human volunteers, using MS. All the samples contained noticeable quantities of (24R)-5b,6b-epoxy-24-ethylcholestan-3b-ol (b-epoxysitostanol) and (24R)-ethylcholestan-3b,5a,6b-triol (sitostanetriol) and also trace levels of (24R)-5a,6a-epoxy-24-ethylcholestan-3b-ol (a-epoxysitostanol), (24R)-methylcholestan-3b,5a,6b-triol (campestanetriol) and (24R)-ethylch olest-5-en-3b-ol-7-one(7-ketositosterol). The amounts of these oxyphytosterols in plasma varied from 4·8 to 57·2 ng/ml. There are two possibilities concerning the origin of these compounds. First, they could come from the sma…
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…
Urinary excretion of heptanones, heptanoles and 2,5-heptanedione after controlled acute exposure of volunteers to n-heptane.
2018
A lack of well-established parameters and assessment values currently impairs biomonitoring of n-heptane exposure. Using controlled inhalation experiments, we collected information on urinary n-heptane metabolite concentrations and the time course of metabolite excretion. Relationships between external and internal exposure were analysed to investigate the suitability of selected metabolites to reflect n-heptane uptake. Twenty healthy, non-smoking males (aged 19-38 years, median 25.5) were exposed for 3 h to 167, 333 and 500 ppm n-heptane, each. Spot urine samples of the volunteers, collected before exposure and during the following 24 h, were analysed for heptane-2-one, 3-one, 4-one, 2,5-d…
Microbial metabolomic fingerprinting in urine after regular dealcoholized red wine consumption in humans.
2013
The regular consumption of dealcoholized red wine (DRW) has demonstrated benefits in cardiovascular risk factors. The analysis of phenolic metabolites formed in the organism, especially those that could come from microbiota metabolism, would help to understand these benefits. The aim of this study was to determine the widest urinary metabolomic fingerprinting of phenolics and microbial-derived phenolic acids (n = 61) after regular intake of DRW in men at high cardiovascular risk by UPLC-MS/MS using a targeted approach. Up to 49 metabolites, including phase II and microbial phenolic metabolites, increased after DRW consumption compared to baseline (P < 0.05). The highest percentage of increa…
Mycotoxin Dietary Exposure Assessment through Fruit Juices Consumption in Children and Adult Population
2019
Consumption of fruit juice is becoming trendy for consumers seeking freshness and high vitamin and low caloric intake. Mycotoxigenic moulds may infect fruits during crop growth, harvest, and storage leading to mycotoxin production. Many mycotoxins are resistant to food processing, which make their presence in the final juice product very likely expected. In this way, the presence of 30 mycotoxins including aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), aflatoxin G2 (AFG2), alternariol (AOH), alternariol monomethyl ether (AME), Ochratoxin A (OTA), fumonisin B1 (FB1), fumonisin B2 (FB2), enniatin A (ENNA), enniatin A1 (ENNA1), enniatin B (ENNB), enniatin B1 (ENNB1), beauverici…
Identification and quantitation of methotrexate and methotrexate metabolites in clinical high-dose therapy by high pressure liquid chromatography and…
1982
High-pressure liquid chromatography in combination with field desorption mass spectrometry as techniques of high specificity and sensitivity have been applied to the identification and quantitation of the anticancer drug methotrexate and its metabolites which occur in clinical high-dose therapy. Field desorption mass spectra of methotrexate and several methotrexate and folic acid derivatives, when investigated as free acids or ammonium salts, yield abundant protonated molecular ions and a consistent pattern of structurally significant fragments. High-pressure liquid chromatographic separation of methotrexate metabolites was performed on reverse-phase, C-18 columns using a volatile, ammonium…
The effect of olive oil polyphenols on antibodies against oxidized LDL. A randomized clinical trial
2010
summary Background & aim: Oxidized LDL (oxLDL) is a highly immunogenic particle that plays a key role in the development of atherosclerosis. Some data suggest a protective role of OxLDL autoantibodies (OLAB) in atherosclerosis. Our aim was to assess the effect of olive oil polyphenols on the immunogenicity of oxLDL to autoantibody generation. Methods: In a crossover, controlled trial, 200 healthy men were randomly assigned to 3-week sequences of 25 mL/day of 3 olive oils with high (366 mg/kg), medium (164 mg/kg), and low (2.7 mg/kg) phenolic content. Results: Plasma OLAB concentration was inversely associated with oxLDL (p < 0.001). Olive oil phenolic content increased OLAB generation, with…
Proteomics of Orbital Tissue in Thyroid-Associated Orbitopathy.
2015
A potentially altered protein expression profile in orbital tissue from patients with thyroid-associated orbitopathy (TAO) is suspected.To detect for the first time changes in proteomic patterns of orbital connective tissue in TAO and compare these with control tissue using mass spectrometry.Proteomics cross-sectional, comparative study.Two academic endocrine institutions.A total of 64 orbital and peripheral adipose tissue samples were collected from 39 patients with TAO and 25 control subjects.Samples were analyzed and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry technology.Mean intensity values of all identified peptides per protein.Thirty-…
Inter-individual variability of protein patterns in saliva of healthy adults
2009
International audience; In order to document inter-individual variability in salivary protein patterns, unstimulated whole saliva was obtained from 12 subjects at 10 am and 3 pm of the same day. Saliva proteins were separated using two-dimensional gel electrophoresis, and semi-quantified using image analysis. One-way ANOVA was used to test the effects “time of sampling” and “subject”. Data were further explored by multivariate analyses (PCA, hierarchical clustering). Spots of interest were identified by mass spectrometry (MALDI-TOF MS/MS and nanoLC ESI-IT MS/MS). A dataset of 509 spots matched in all gels was obtained. There was no diurnal statistical effect on salivary patterns while inter…