| 1. |
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| 2. |
- Pierre, Pernilla Videhult, et al.
(författare)
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Cisplatin-induced metabolome changes in serum : an experimental approach to identify markers for ototoxicity
- 2017
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Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 0001-6489 .- 1651-2251. ; 137:10, s. 1024-1030
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Ototoxicity from treatment with the anticancer drug cisplatin remains a clinical problem. A wide range of intracellular targets of cisplatin has been found in vivo.AIM: To investigate cisplatin-induced change of the serum metabolite profile and its association with ototoxicity.MATERIAL AND METHODS: Guinea pigs (n = 14) were treated with cisplatin (8 mg/kg b.w., i.v.) 30 min after administration of the otoprotector candidate sodium thiosulfate (group STS; n = 7) or sodium chloride (group NaCl; n = 7). Ototoxicity was evaluated by ABR (3-30 kHz) before and 4 d after drug treatment, and by assessment of hair cell loss. A blood sample was drawn before and 4 d after drug treatment and the polar metabolome in serum was analyzed using LC-MS.RESULTS: Cisplatin-treatment caused significant threshold elevations and outer hair cell (OHC) loss in both groups. The ototoxicity was generally lower in group STS, but a significant difference was reached only at 30 kHz (p = .007). Cisplatin treatment altered the metabolite profile significantly and similarly in both groups. A significant inverse correlation was found between L-acetylcarnitine, N-acetylneuraminic acid, ceramide, and cysteinylserine and high frequency hearing loss in group NaCl. The implication of these correlations should be explored in targeted studies.
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| 3. |
- Engskog, Mikael K R, et al.
(författare)
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The cyanobacterial amino acid beta-N-methylamino-L-alanine perturbs the intermediary metabolism in neonatal rats
- 2013
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Ingår i: Amino Acids. - : Elsevier BV. - 0939-4451 .- 1438-2199. ; 49:5, s. 905-919
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Tidskriftsartikel (refereegranskat)abstract
- The neurotoxic amino acid β-N-methylamino-l-alanine (BMAA) is produced by most cyanobacteria. BMAA is considered as a potential health threat because of its putative role in neurodegenerative diseases. We have previously observed cognitive disturbances and morphological brain changes in adult rodents exposed to BMAA during the development. The aim of this study was to characterize changes of major intermediary metabolites in serum following neonatal exposure to BMAA using a non-targeted metabolomic approach. NMR spectroscopy was used to obtain serum metabolic profiles from neonatal rats exposed to BMAA (40, 150, 460mg/kg) or vehicle on postnatal days 9-10. Multivariate data analysis of binned NMR data indicated metabolic pattern differences between the different treatment groups. In particular five metabolites, d-glucose, lactate, 3-hydroxybutyrate, creatine and acetate, were changed in serum of BMAA-treated neonatal rats. These metabolites are associated with changes in energy metabolism and amino acid metabolism. Further statistical analysis disclosed that all the identified serum metabolites in the lowest dose group were significantly (p<0.05) decreased. The neonatal rat model used in this study is so far the only animal model that displays significant biochemical and behavioral effects after a low short-term dose of BMAA. The demonstrated perturbation of intermediary metabolism may contribute to BMAA-induced developmental changes that result in long-term effects on adult brain function.
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| 4. |
- Barclay, Victoria K.H.
(författare)
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Development of LC-MS/MS Methods for the Analysis of Chiral and Achiral Pharmaceuticals and Metabolites in Aqueous Environmental Matrices
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis describes the development of liquid chromatography tandem mass spectrometry (LC-MS/MS) methods for the trace analysis of active pharmaceutical ingredients (APIs) and their metabolites in aqueous environmental matrices. The research was focused on the development of chiral LC-MS/MS methods for the analysis of fluoxetine and metoprolol, as well as their chiral metabolites in environmental water samples. A method was also developed for the achiral compounds, diazepam and nordiazepam. The LC-MS/MS methods were validated by the use of the isotope-labeled compounds. As these isotope-labeled compounds were not found in the wastewater samples, the validation could be assessed at trace level concentrations in the actual matrices in which the analytes were detected. The analytes were extracted from the water samples using solid phase extraction methods. Different types of solid phase extraction sorbents were evaluated. Fluoxetine and norfluoxetine were extracted through the use of a mixed mode polymeric based extraction sorbent. A hydrophilic and lipophilic balanced sorbent was employed for the simultaneous extraction of metoprolol and its metabolites, the base α-hydroxymetoprolol and the acidic metabolite deaminated metoprolol. Moreover, silica based C18 extraction discs were applied for the sample preparation of diazepam and nordiazepam. The chromatographic separations were conducted in reversed phase LC with MS compatible mobile phases. The enantiomers of fluoxetine and norfluoxetine were simultaneously separated using the chiral stationary phase (CSP), α1-acid glycoprotein (AGP). The Chiral AGP column was also applied for the separation of the enantiomers of deaminated metoprolol. For the simultaneous separation of the metoprolol enantiomers and the four stereoisomers of α-hydroxymetoprolol, the cellobiohydrolase (CBH) protein based CSP was used. An octadecyl silica based LC column was applied for the separation of diazepam and nordiazepam. The analytes were detected by the use of tandem quadrupole mass spectrometry operating in selective reactive monitoring mode. High resolution MS, employing a quadrupole time-of-flight (QqTOF) mass analyzer, was utilized for the identification of an unknown compound in wastewater samples. The APIs and their metabolites, as well as their respective enantiomers, were quantified in raw and treated wastewater from Uppsala, Sweden along with surface water from the River Fyris in Uppsala.
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| 5. |
- Barclay, Victoria K H, et al.
(författare)
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Trace analysis of fluoxetine and its metabolite norfluoxetine. Part II : Enantioselective quantification and studies of matrix effects in raw and treated wastewater by solid phase extraction and liquid chromatography-tandem mass spectrometry
- 2012
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Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1227, s. 105-114
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Tidskriftsartikel (refereegranskat)abstract
- The isotope-labeled compounds fluoxetine-d5 and norfluoxetine-d5 were used to study matrix effects caused by co-eluting compounds originating from raw and treated wastewater samples, collected in Uppsala, Sweden. The matrix effects were investigated by the determination of matrix factors (MF) and by a post-column infusion method. The matrix factors were determined to be 38–47% and 71–86% for the enantiomers of norfluoxetine-d5 and fluoxetine-d5, respectively. The influence of matrix effects when quantifying the enantiomers of the active pharmaceutical ingredient and the metabolite in wastewater samples with LC–MS/MS is discussed and methods to overcome the problem are presented. The enantiomeric concentrations of fluoxetine and its human metabolite norfluoxetine, quantified by a one-point calibration method, were 12–52 pM (3.5–16 ng L−1) in raw wastewater and 4–48 pM (1.2–15 ng L−1) in treated wastewater. Furthermore, the calculated enantiomeric fractions (EF) of the substances were found to be between 0.68 and 0.71 in both matrices. Neither the EF values for fluoxetine nor those for norfluoxetine were significantly different in the raw wastewater compared to the treated wastewater. Interestingly, the concentration of (S)-fluoxetine was found to be higher than the concentration of (R)-fluoxetine in both raw and treated wastewater. These results are different from other results presented in the literature, which shows that the relative concentrations of the enantiomers of a chiral active pharmaceutical ingredient might be significantly different in wastewater samples from different treatment systems. We report, for the first time, the concentrations of the enantiomers of norfluoxetine in wastewater samples. The concentrations of (S)-norfluoxetine were found to be higher than the concentration of (R)-norfluoxetine in the raw as well as in the treated wastewater samples.
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| 6. |
- Fransson, Anette E, et al.
(författare)
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Hydrogen Inhalation Protects against Ototoxicity Induced by Intravenous Cisplatin in the Guinea Pig
- 2017
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Ingår i: Frontiers in Cellular Neuroscience. - : Frontiers Media SA. - 1662-5102. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Permanent hearing loss and tinnitus as side-effects from treatment with the anticancer drug cisplatin is a clinical problem. Ototoxicity may be reduced by co-administration of an otoprotective agent, but the results in humans have so far been modest.Aim: The present preclinical in vivo study aimed to explore the protective efficacy of hydrogen (H2) inhalation on ototoxicity induced by intravenous cisplatin.Materials and Methods: Albino guinea pigs were divided into four groups. The Cispt (n = 11) and Cispt+H2 (n = 11) groups were given intravenous cisplatin (8 mg/kg b.w., injection rate 0.2 ml/min). Immediately after, the Cispt+H2 group also received gaseous H2 (2% in air, 60 min). The H2 group (n = 5) received only H2 and the Control group (n = 7) received neither cisplatin nor H2. Ototoxicity was assessed by measuring frequency specific ABR thresholds before and 96 h after treatment, loss of inner (IHCs) and outer (OHCs) hair cells, and by performing densitometry-based immunohistochemistry analysis of cochlear synaptophysin, organic transporter 2 (OCT2), and copper transporter 1 (CTR1) at 12 and 7 mm from the round window. By utilizing metabolomics analysis of perilymph the change of metabolites in the perilymph was assessed.Results: Cisplatin induced electrophysiological threshold shifts, hair cell loss, and reduced synaptophysin immunoreactivity in the synapse area around the IHCs and OHCs. H2 inhalation mitigated all these effects. Cisplatin also reduced the OCT2 intensity in the inner and outer pillar cells and in the stria vascularis as well as the CTR1 intensity in the synapse area around the IHCs, the Deiters' cells, and the stria vascularis. H2 prevented the majority of these effects.Conclusion: H2 inhalation can reduce cisplatin-induced ototoxicity on functional, cellular, and subcellular levels. It is proposed that synaptopathy may serve as a marker for cisplatin ototoxicity. The effect of H2 on the antineoplastic activity of cisplatin needs to be further explored.
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| 7. |
- Lindell Jonsson, Eva, et al.
(författare)
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Exploring Radiation Response in Two Head and Neck Squamous Carcinoma Cell Lines Through Metabolic Profiling
- 2019
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Ingår i: Frontiers in Oncology. - : Frontiers Media SA. - 2234-943X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Head and neck squamous cell carcinoma (HNSCC) is the sixth most common form of cancer worldwide. Radiotherapy, with or without surgery, represents the major approach to curative treatment. However, not all tumors are equally sensitive to irradiation. It is therefore of interest to apply newer system biology approaches (e.g., metabolic profiling) in squamous cancer cells with different radiosensitivities in order to provide new insights on the mechanisms of radiation response. In this study, two cultured HNSCC cell lines from the same donor, UM-SCC-74A and UM-SCC-74B, were first genotyped using Short Tandem Repeat (STR), and assessed for radiation response by the means of clonogenic survival and growth inhibition assays. Thereafter, cells were cultured, irradiated and collected for subsequent metabolic profiling analyses using liquid chromatography-mass spectrometry (LC-MS). STR verified the similarity of UM-SCC-74A and UM-SCC-74B cells, and three independent assays proved UM-SCC-74B to be clearly more radioresistant than UM-SCC-74A. The LC-MS metabolic profiling demonstrated significant differences in the intracellular metabolome of the two cell lines before irradiation, as well as significant alterations after irradiation. The most important differences between the two cell lines before irradiation were connected to nicotinic acid and nicotinamide metabolism and purine metabolism. In the more radiosensitive UM-SCC-74A cells, the most significant alterations after irradiation were linked to tryptophan metabolism. In the more radioresistant UM-SCC-74B cells, the major alterations after irradiation were connected to nicotinic acid and nicotinamide metabolism, purine metabolism, the methionine cycle as well as the serine, and glycine metabolism. The data suggest that the more radioresistant cell line UM-SCC-74B altered the metabolism to control redox-status, manage DNA-repair, and change DNA methylation after irradiation. This provides new insights on the mechanisms of radiation response, which may aid future identification of biomarkers associated with radioresistance of cancer cells.
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| 8. |
- Barclay, Victoria K.H., et al.
(författare)
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Chiral analysis of metoprolol and two of its metabolites, alpha‑hydroxymetoprolol and deaminated metoprolol, in wastewater using liquid chromatography-tandem mass spectrometry
- 2012
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Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1269:SI, s. 208-217
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Tidskriftsartikel (refereegranskat)abstract
- A LC–MS/MS method for the chiral separation of metoprolol and two of its main metabolites, α-hydroxymetoprolol (α-OH-Met) and deaminated metoprolol (COOH-Met), in environmental water samples has been developed. The target bases, metoprolol and α-OH-Met, as well as the acidic metabolite (COOH-Met) were extracted from water samples by a solid phase extraction method employing Oasis HLB cartridges. The extraction recoveries were ≥73% for all compounds in surface water. Four different types of chiral stationary phases were investigated for the separation of the eight stereoisomers of metoprolol and its metabolites, Chiralcel OD-H, Chirobiotic V, Chiral AGP and Chiral CBH. In the final method, the enantiomers of metoprolol and four stereoisomers of α-OH-Met were separated using Chiral CBH, the enantiomers of COOH-Met were separated employing Chiral AGP. The analytes were detected in SRM mode by triple quadrupole mass spectrometry. The method was applied for the chiral analysis of the analytes in treated wastewater samples from Uppsala, Sweden. The enantiomers and diastereoisomers of α-OH-Met were detected and analyzed in the samples. The concentrations of the three first eluting stereoisomers of α-OH-Met were between 54 and 61 pM. Interestingly, the last eluting stereoisomer was found to be present at a concentration of 151 pM at the same sampling occasion. This is, to the best of the authors’ knowledge, the first time the stereoisomers of α-OH-Met have been detected in wastewater samples. The enantiomers of metoprolol were determined to be 1.77 and 1.86 nM in the same matrix. The enantiomers of COOH-Met were not detected above the method detection limit (42 pM) in treated wastewater samples. The developed LC–MS/MS methods were validated in wastewater samples.
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| 9. |
- Elmsjö, Albert, 1986-
(författare)
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Selectivity in NMR and LC-MS Metabolomics : The Importance of Sample Preparation and Separation, and how to Measure Selectivity in LC-MS Metabolomics.
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Until now, most metabolomics protocols have been optimized towards high sample throughput and high metabolite coverage, parameters considered to be highly important for identifying influenced biological pathways and to generate as many potential biomarkers as possible. From an analytical point of view this can be troubling, as neither sample throughput nor the number of signals relates to actual quality of the detected signals/metabolites. However, a method’s selectivity for a specific signal/metabolite is often closely associated to the quality of that signal, yet this is a parameter often neglected in metabolomics.This thesis demonstrates the importance of considering selectivity when developing NMR and LC-MS metabolomics methods, and introduces a novel approach for measuring chromatographic and signal selectivity in LC-MS metabolomics.Selectivity for various sample preparations and HILIC stationary phases was compared. The choice of sample preparation affected the selectivity in both NMR and LC-MS. For the stationary phases, selectivity differences related primarily to retention differences of unwanted matrix components, e.g. inorganic salts or glycerophospholipids. Metabolites co-eluting with these matrix components often showed an incorrect quantitative signal, due to an influenced ionization efficiency and/or adduct formation.A novel approach for measuring selectivity in LC-MS metabolomics has been introduced. By dividing the intensity of each feature (a unique mass at a specific retention time) with the total intensity of the co-eluting features, a ratio representing the combined chromatographic (amount of co-elution) and signal (e.g. in-source fragmentation) selectivity is acquired. The calculated co-feature ratios have successfully been used to compare the selectivity of sample preparations and HILIC stationary phases.In conclusion, standard approaches in metabolomics research might be unwise, as each metabolomics investigation is often unique. The methods used should be adapted for the research question at hand, primarily based on any key metabolites, as well as the type of sample to be analyzed. Increased selectivity, through proper choice of analytical methods, may reduce the risks of matrix-associated effects and thereby reduce the false positive and false negative discovery rate of any metabolomics investigation.
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| 10. |
- Elmsjö, Albert, et al.
(författare)
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The co-feature ratio, a novel method for the measurement of chromatographic and signal selectivity in LC-MS-based metabolomics.
- 2017
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Ingår i: Analytica Chimica Acta. - : Elsevier BV. - 0003-2670 .- 1873-4324. ; 956, s. 40-47
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Tidskriftsartikel (refereegranskat)abstract
- Evaluation of analytical procedures, especially in regards to measuring chromatographic and signal selectivity, is highly challenging in untargeted metabolomics. The aim of this study was to suggest a new straightforward approach for a systematic examination of chromatographic and signal selectivity in LC-MS-based metabolomics. By calculating the ratio between each feature and its co-eluting features (the co-features), a measurement of the chromatographic selectivity (i.e. extent of co-elution) as well as the signal selectivity (e.g. amount of adduct formation) of each feature could be acquired, the co-feature ratio. This approach was used to examine possible differences in chromatographic and signal selectivity present in samples exposed to three different sample preparation procedures. The capability of the co-feature ratio was evaluated both in a classical targeted setting using isotope labelled standards as well as without standards in an untargeted setting. For the targeted analysis, several metabolites showed a skewed quantitative signal due to poor chromatographic selectivity and/or poor signal selectivity. Moreover, evaluation of the untargeted approach through multivariate analysis of the co-feature ratios demonstrated the possibility to screen for metabolites displaying poor chromatographic and/or signal selectivity characteristics. We conclude that the co-feature ratio can be a useful tool in the development and evaluation of analytical procedures in LC-MS-based metabolomics investigations. Increased selectivity through proper choice of analytical procedures may decrease the false positive and false negative discovery rate and thereby increase the validity of any metabolomic investigation.
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