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Nakken CL, Meier S, Mjøs SA, Bijlsma L, Rowland SJ, Donald CE. Discovery of polycyclic aromatic acid metabolites in fish exposed to the petroleum compounds 1-methylphenanthrene and 1,4-dimethylphenanthrene. Sci Total Environ 2024; 918:170496. [PMID: 38296090 DOI: 10.1016/j.scitotenv.2024.170496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/09/2024]
Abstract
Most of the polycyclic aromatic hydrocarbons (PAHs) in petroleum are alkylated (alkyl PAHs), still the metabolism of these alkyl PAHs to the expected acid products (polycyclic aromatic acids; PAAs) has yet to be demonstrated in oil-exposed fish. Should these compounds be discovered in fish as they have in ragworm, rodents, and humans, they could present an indicative biomarker for assessing oil pollution. In this study, the ability to biotransform alkyl PAHs to PAAs was examined on Atlantic haddock (Melanogrammus aeglefinus). Exposure to phenanthrene, 1-methyphenanthrene or 1,4-dimethylphenanthrene was performed via intraperitoneal injection. An Ion Mobility Quadrupole Time-Of-Flight Mass Spectrometer (IMS-Q-TOF MS) was used in exploratory analysis of extracted bile samples. Acquisition of four-dimensional information by coupling liquid chromatography with the IMS-Q-TOF MS and in-silico prediction for feature prioritization in the data processing workflow allowed several tentative identifications with high degree of confidence. This work presents the first detection of PAAs in fish and suggests the importance of investigating alkyl PAHs in ecotoxicological studies of oil-polluted fish environments.
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Affiliation(s)
- Charlotte L Nakken
- Department of Chemistry, University of Bergen, Bergen, Norway; Marine Toxicology, Institute of Marine Research, Bergen, Norway
| | - Sonnich Meier
- Marine Toxicology, Institute of Marine Research, Bergen, Norway
| | - Svein A Mjøs
- Department of Chemistry, University of Bergen, Bergen, Norway
| | - Lubertus Bijlsma
- Environmental and Public Health Analytical Chemistry, Research Institute for Pesticides and Water, University Jaume I, Castellón, Spain
| | - Steven J Rowland
- Petroleum & Environmental Geochemistry Group, Biogeochemistry Research Centre, University of Plymouth, Plymouth, PL4 8AA, Devon, UK
| | - Carey E Donald
- Marine Toxicology, Institute of Marine Research, Bergen, Norway.
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2
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Chhaganlal MN, Underhaug J, Mjøs SA. Evaluation of NMR predictors for accuracy and ability to reveal trends in 1 H NMR spectra of fatty acids. Magn Reson Chem 2023; 61:318-332. [PMID: 36759332 DOI: 10.1002/mrc.5336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/04/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
Four different nuclear magnetic resonance (NMR) predictors have been evaluated for their ability to predict 600-MHz 1 H spectra of free fatty acids and fatty acid methyl esters of 20 common fatty acids. The predictors were evaluated on two main criteria: (1) their accuracy in direct prediction of the spectra (absolute accuracy) and (2) the ability to reveal trends or predict the change that occurs in the spectra as a result of a change in the fatty acid carbon chain, or by esterification of the free fatty acids to methyl esters (relative accuracy). The absolute accuracy in chemical shift prediction for fatty acids was good, compared with previous reports on a broader range of compounds. All four predictors had median prediction errors for chemical shifts of the signals in fatty acid methyl esters well below 0.1 ppm and as low as 0.015 ppm for one of the predictors. However, all predictors also had outliers with errors far above the upper interquartile range. In general, they also fail to reproduce trends of diagnostic value that were observed in the experimental data or properly predict the result of a minor change in molecular structure. All four predictors depend on experimental data from different origins. This may be a limiting factor for the relative accuracy of the predictors.
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Affiliation(s)
| | - Jarl Underhaug
- Department of Chemistry, University of Bergen, Bergen, Norway
| | - Svein A Mjøs
- Department of Chemistry, University of Bergen, Bergen, Norway
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3
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Lin CC, Sengee A, Mjøs SA. Minor compounds and potential interferents in gas chromatographic analyses of human serum fatty acids. J Chromatogr B Analyt Technol Biomed Life Sci 2020; 1138:121963. [DOI: 10.1016/j.jchromb.2019.121963] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 12/19/2019] [Accepted: 12/28/2019] [Indexed: 11/29/2022]
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4
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Hovland IH, Leikanger IS, Stokkeland O, Waage KH, Mjøs SA, Brokstad KA, McCann A, Ueland PM, Slizyte R, Carvajal A, Mellgren G, Remman T, Høgøy I, Gudbrandsen OA. Effects of low doses of fish and milk proteins on glucose regulation and markers of insulin sensitivity in overweight adults: a randomised, double blind study. Eur J Nutr 2019; 59:1013-1029. [DOI: 10.1007/s00394-019-01963-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 04/02/2019] [Indexed: 12/11/2022]
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5
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Vikøren LA, Drotningsvik A, Bergseth MT, Mjøs SA, Austgulen MH, Mellgren G, Gudbrandsen OA. Intake of Baked Cod Fillet Resulted in Lower Serum Cholesterol and Higher Long Chain n-3 PUFA Concentrations in Serum and Tissues in Hypercholesterolemic Obese Zucker fa/fa Rats. Nutrients 2018; 10:E840. [PMID: 29958397 PMCID: PMC6073601 DOI: 10.3390/nu10070840] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 06/15/2018] [Accepted: 06/26/2018] [Indexed: 12/12/2022] Open
Abstract
Increasing evidence indicates that lean fish consumption may benefit cardiovascular health. High cholesterol and low n-3 PUFA concentrations in serum are associated with an increased risk of coronary heart disease; therefore, it is of interest to investigate effects of cod intake on cholesterol and n-3 PUFAs in serum and tissues. Hypercholesterolemic obese Zucker fa/fa rats were fed diets containing 25% protein from baked cod fillet and 75% protein from casein (Baked Cod Diet), or casein as the sole protein source (Control Diet) for four weeks. Consuming Baked Cod Diet resulted in lower serum cholesterol and lower hepatic mRNA concentrations of HMG-CoA reductase and sterol O-acyltransferase-2 without affecting serum bile acid concentration, faecal excretion of cholesterol and bile acid, and hepatic concentrations of bile acids, cholesterol and cholesterol 7 alpha-hydroxylase mRNA when compared to Control Diet. Rats fed Baked Cod Diet had higher concentrations of n-3 PUFAs in serum, liver, skeletal muscle and adipose tissue. To conclude, baked cod fillet intake resulted in lower serum cholesterol, which was probably caused by lower endogenous cholesterol synthesis, and higher n-3 PUFA in serum and tissues in obese Zucker fa/fa rats. These findings support the evidence that lean fish consumption might benefit cardiovascular health.
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Affiliation(s)
- Linn A Vikøren
- Dietary Protein Research Group, Department of Clinical Medicine, University of Bergen, 5021 Bergen, Norway.
- Department of Clinical Science, University of Bergen, 5021 Bergen, Norway.
| | - Aslaug Drotningsvik
- Dietary Protein Research Group, Department of Clinical Medicine, University of Bergen, 5021 Bergen, Norway.
| | - Marthe T Bergseth
- Dietary Protein Research Group, Department of Clinical Medicine, University of Bergen, 5021 Bergen, Norway.
| | - Svein A Mjøs
- Department of Chemistry, University of Bergen, P.O. Box 7803, 5020 Bergen, Norway.
- Nofima BioLab, P.O. Box 1425 Oasen, 5828 Bergen, Norway.
| | - Maren H Austgulen
- Department of Clinical Science, University of Bergen, 5021 Bergen, Norway.
| | - Gunnar Mellgren
- Department of Clinical Science, KG Jebsen Center for Diabetes Research, University of Bergen, Haukeland University Hospital, 5021 Bergen, Norway.
- Hormone Laboratory, Haukeland University Hospital, 5021 Bergen, Norway.
| | - Oddrun A Gudbrandsen
- Dietary Protein Research Group, Department of Clinical Medicine, University of Bergen, 5021 Bergen, Norway.
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6
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Waktola HD, Mjøs SA. Chromatographic efficiency of polar capillary columns applied for the analysis of fatty acid methyl esters by gas chromatography. J Sep Sci 2018; 41:1582-1592. [PMID: 29314609 DOI: 10.1002/jssc.201700908] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 11/21/2017] [Accepted: 12/12/2017] [Indexed: 11/11/2022]
Abstract
The chromatographic efficiency that could be achieved in temperature-programmed gas chromatography was compared for four capillary columns that are typically applied for analysis of fatty acid methyl esters (FAME). Three different carrier gases, hydrogen, helium and nitrogen, were applied. For each experiment, the carrier gas velocities and the temperature rates were varied with a full 9 × 3 design, with nine levels on the carrier gas velocity and temperature rates of 1, 2 or 3°C/min. Response surface methodology was used to create models of chromatographic efficiency as a function of temperature rate and carrier gas velocity. The chromatographic efficiency was defined as the inverse of peak widths measured in retention index units. The final results were standardized so that the efficiencies that could be achieved within a certain time frame, defined by the retention time of the last compound in the chromatogram, could be compared. The results show that there were clear differences in the efficiencies that could be achieved with the different columns and that the efficiency decreased with increasing polarity of the stationary phase. The differences can be explained by higher resistance to mass transfer in the stationary phase in the most polar columns.
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Affiliation(s)
| | - Svein A Mjøs
- Department of Chemistry, University of Bergen, Bergen, Norway
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7
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Steinrücken P, Mjøs SA, Prestegard SK, Erga SR. Enhancing EPA Content in an Arctic Diatom: A Factorial Design Study to Evaluate Interactive Effects of Growth Factors. Front Plant Sci 2018; 9:491. [PMID: 29755487 PMCID: PMC5932356 DOI: 10.3389/fpls.2018.00491] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 04/03/2018] [Indexed: 05/20/2023]
Abstract
Microalgae with a high content of the omega-3 polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) are of great demand for microalgae-based technologies. An Arctic strain of the diatom Attheya septentrionalis was shown in previous experiments to increase its EPA content from 3.0 to 4.6% of dry weight (DW) in the nutrient-replete exponential phase and nutrient-depleted stationary phase, respectively. In the present study, a factorial-design experiment was used, to investigate this effect in more detail and in combination with varying salinities and irradiances. A mathematical model revealed that both growth phase and salinity, alone and in combination, influenced the EPA content significantly. Maximum EPA values of 7.1% DW were obtained at a salinity of 22 and after 5 days in stationary phase, and might be related to a decreased silica content, an accumulation of storage lipids containing EPA, or both. However, growth rates were lower for low salinity (0.54 and 0.57 d-1) than high salinity (0.77 and 0.98 d-1) cultures.
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Affiliation(s)
- Pia Steinrücken
- Department of Biological Sciences, University of Bergen, Bergen, Norway
- *Correspondence: Pia Steinrücken
| | - Svein A. Mjøs
- Department of Chemistry, University of Bergen, Bergen, Norway
| | | | - Svein R. Erga
- Department of Biological Sciences, University of Bergen, Bergen, Norway
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8
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Vikøren LA, Drotningsvik A, Bergseth MT, Mjøs SA, Mola N, Leh S, Mellgren G, Gudbrandsen OA. Effects of baked and raw salmon fillet on lipids and n-3 PUFAs in serum and tissues in Zucker fa/fa rats. Food Nutr Res 2017; 61:1333395. [PMID: 28659746 PMCID: PMC5475302 DOI: 10.1080/16546628.2017.1333395] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/18/2017] [Indexed: 01/13/2023] Open
Abstract
Knowledge of the health impact of consuming heat-treated versus raw fish fillet is limited. To investigate effects of baked or raw salmon fillet intake on lipids and n-3 PUFAs in serum and tissues, obese Zucker fa/fa rats were fed diets containing 25% of protein from baked or raw salmon fillet and 75% of protein from casein, or casein as the sole protein source (control group) for four weeks. Salmon diets had similar composition of amino and fatty acids. Growth and energy intake were similar in all groups. Amounts of lipids and n-3 PUFAs in serum, liver and skeletal muscle were similar between rats fed baked or raw salmon fillet. When compared to the control group, rats fed baked salmon had lower serum total and LDL cholesterol and higher serum triacylglycerol levels. Both raw and baked salmon groups had lower HDL cholesterol level when compared to control rats. In conclusion, baking as a preparation method does not alter protein and fat qualities of salmon fillets, and intake of baked and raw salmon fillets gave similar effects on lipids and n-3 PUFAs in serum and tissues from rats.
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Affiliation(s)
- Linn A Vikøren
- Dietary Protein Research Group, Department of Clinical Medicine, University of Bergen, Bergen, Norway.,Department of Clinical Science, University of Bergen, Haukeland University Hospital, Bergen, Norway
| | - Aslaug Drotningsvik
- Dietary Protein Research Group, Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Marthe T Bergseth
- Dietary Protein Research Group, Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Svein A Mjøs
- Department of Chemistry, University of Bergen, Bergen, Norway.,Nofima BioLab, Bergen, Norway
| | - Nazanin Mola
- Department of Pathology, Haukeland University Hospital, Bergen, Norway
| | - Sabine Leh
- Department of Pathology, Haukeland University Hospital, Bergen, Norway.,Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Gunnar Mellgren
- Department of Clinical Science, KG Jebsen Center for Diabetes Research, University of Bergen, Haukeland University Hospital, 5021Bergen, Norway.,Hormone Laboratory, Haukeland University Hospital, 5021Bergen, Norway
| | - Oddrun A Gudbrandsen
- Dietary Protein Research Group, Department of Clinical Medicine, University of Bergen, Bergen, Norway
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9
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Sørensen L, Meier S, Mjøs SA. Application of gas chromatography/tandem mass spectrometry to determine a wide range of petrogenic alkylated polycyclic aromatic hydrocarbons in biotic samples. Rapid Commun Mass Spectrom 2016; 30:2052-2058. [PMID: 27470186 DOI: 10.1002/rcm.7688] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 07/13/2016] [Accepted: 07/13/2016] [Indexed: 06/06/2023]
Abstract
RATIONALE Due to the inherent toxicity of these compounds, analysis of petrogenic alkylated polycyclic aromatic hydrocarbons (PAHs) and heteroaromatic compounds in environmental samples is crucial. However, most existing methods are not sensitive enough when the analyte concentrations are low. Gas chromatography/tandem mass spectrometry (GC/MS/MS) is well suited to tackle this challenge, but methods are yet to be fully developed. METHODS A gas chromatograph coupled with a triple quadrupole mass spectrometer operated in multiple reaction monitoring (MRM) mode was applied for the analysis. MRM transitions and analytical conditions were optimized for the cluster analysis of 24 different compound classes of alkylated PAHs and heteroaromatics present in crude oils. Further, the method was verified and applied to analyze the body burden of these compounds in crude oil-exposed haddock eggs. RESULTS A comprehensive and sensitive method for the determination of C1-C4 alkylated naphthalenes, benzothiophenes, fluorenes, phenanthrenes, dibenzothiophenes, chrysenes, pyrenes and fluoranthenes was developed. The method showed good precision (RSD <15%), and the obtained concentrations were similar to those obtained by traditional GC/MS analysis. CONCLUSIONS We demonstrate the successful application of this method towards crude oil-exposed fish eggs, where we are able to precisely measure total PAH body burden below 0.5 μg/g. The demonstrated method facilitates further miniaturization in sample preparation. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Lisbet Sørensen
- Institute of Marine Research, P.O. Box 1870, Nordnes, NO-5817, Bergen, Norway
- Department of Chemistry, University of Bergen, P.O. Box 7800, NO-5020, Bergen, Norway
| | - Sonnich Meier
- Institute of Marine Research, P.O. Box 1870, Nordnes, NO-5817, Bergen, Norway
| | - Svein A Mjøs
- Department of Chemistry, University of Bergen, P.O. Box 7800, NO-5020, Bergen, Norway
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Lin C, Andersen JR, Våge V, Rajalahti T, Mjøs SA, Kvalheim OM. Intensive lifestyle intervention provides rapid reduction of serum fatty acid levels in women with severe obesity without lowering omega-3 to unhealthy levels. Clin Obes 2016; 6:259-67. [PMID: 27334055 PMCID: PMC5129509 DOI: 10.1111/cob.12151] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Revised: 04/24/2016] [Accepted: 05/06/2016] [Indexed: 11/29/2022]
Abstract
Serum fatty acid (FA) levels were monitored in women with severe obesity during intensive lifestyle intervention. At baseline, total FA levels and most individual FAs were elevated compared to a matching cohort of normal and overweight women (healthy controls). After 3 weeks of intensive lifestyle intervention, total level was only 11-12% higher than in the healthy controls and with almost all FAs being significantly lower than at baseline, but with levels of omega-3 being similar to the healthy controls. This is contrary to observations for patients subjected to bariatric surgery where omega-3 levels dropped to levels significantly lower than in the lifestyle patients and healthy controls. During the next 3 weeks of treatment, the FA levels in lifestyle patients were unchanged, while the weight loss continued at almost the same rate as in the first 3 weeks. Multivariate analysis revealed that weight loss and change of serum FA patterns were unrelated outcomes of the intervention for lifestyle patients. For bariatric patients, these processes were associated probably due to reduced dietary input and increased input from the patients' own fat deposits, causing a higher rate of weight loss and simultaneous reduction of the ratio of serum eicosapentaenoic to arachidonic acid.
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Affiliation(s)
- C Lin
- Fjordomics, Førde Hospital Trust, Førde, Norway
- Department of Chemistry, University of Bergen, Bergen, Norway
| | - J R Andersen
- Faculty of Health Studies, Sogn og Fjordane University College, Førde, Norway
- Center of Health research, Førde Hospital Trust, Førde, Norway
| | - V Våge
- Center of Health research, Førde Hospital Trust, Førde, Norway
- Department of Surgery, Voss Hospital, Bergen Health Trust, Voss, Norway
| | - T Rajalahti
- Fjordomics, Førde Hospital Trust, Førde, Norway
| | - S A Mjøs
- Department of Chemistry, University of Bergen, Bergen, Norway
| | - O M Kvalheim
- Department of Chemistry, University of Bergen, Bergen, Norway
- Faculty of Health Studies, Sogn og Fjordane University College, Førde, Norway
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11
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Giskeødegård GF, Hansen AF, Bertilsson H, Gonzalez SV, Kristiansen KA, Bruheim P, Mjøs SA, Angelsen A, Bathen TF, Tessem MB. Metabolic markers in blood can separate prostate cancer from benign prostatic hyperplasia. Br J Cancer 2015; 113:1712-9. [PMID: 26633561 PMCID: PMC4702000 DOI: 10.1038/bjc.2015.411] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 10/28/2015] [Accepted: 11/04/2015] [Indexed: 02/06/2023] Open
Abstract
Background: An individualised risk-stratified screening for prostate cancer (PCa) would select the patients who will benefit from further investigations as well as therapy. Current detection methods suffer from low sensitivity and specificity, especially for separating PCa from benign prostatic conditions. We have investigated the use of metabolomics analyses of blood samples for separating PCa patients and controls with benign prostatic hyperplasia (BPH). Methods: Blood plasma and serum samples from 29 PCa patient and 21 controls with BPH were analysed by metabolomics analysis using magnetic resonance spectroscopy, mass spectrometry and gas chromatography. Differences in blood metabolic patterns were examined by multivariate and univariate statistics. Results: By combining results from different methodological platforms, PCa patients and controls were separated with a sensitivity and specificity of 81.5% and 75.2%, respectively. Conclusions: The combined analysis of serum and plasma samples by different metabolomics measurement techniques gave successful discrimination of PCa and controls, and provided metabolic markers and insight into the processes characteristic of PCa. Our results suggest changes in fatty acid (acylcarnitines), choline (glycerophospholipids) and amino acid metabolism (arginine) as markers for PCa compared with BPH.
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Affiliation(s)
- Guro F Giskeødegård
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology (NTNU), Trondheim 7491, Norway.,St Olav University Hospital, Trondheim 7006, Norway
| | - Ailin Falkmo Hansen
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology (NTNU), Trondheim 7491, Norway
| | - Helena Bertilsson
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim 7491, Norway.,Department of Urology, NTNU, Trondheim 7491, Norway
| | | | | | - Per Bruheim
- Department of Biotechnology, NTNU, Trondheim 7491, Norway
| | - Svein A Mjøs
- Department of Chemistry, University of Bergen, Bergen 5020, Norway
| | - Anders Angelsen
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology (NTNU), Trondheim 7491, Norway.,St Olav University Hospital, Trondheim 7006, Norway
| | - Tone Frost Bathen
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology (NTNU), Trondheim 7491, Norway
| | - May-Britt Tessem
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology (NTNU), Trondheim 7491, Norway.,St Olav University Hospital, Trondheim 7006, Norway
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12
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Mjøs SA, Waktola HD. Optimizing the relationship between chromatographic efficiency and retention times in temperature-programmed gas chromatography. J Sep Sci 2015; 38:3014-27. [PMID: 26105965 DOI: 10.1002/jssc.201500364] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 06/03/2015] [Accepted: 06/04/2015] [Indexed: 11/11/2022]
Abstract
A methodology that can maximise the chromatographic efficiency that can be achieved within a defined time frame in temperature-programmed gas chromatography is described. The efficiency can be defined as the inverse of peak widths measured in retention index units. This parameter can be described by a model similar to the van Deemter equation, which is expanded to account for the effect of the temperature rate in addition to the effect of carrier gas velocity. The model of efficiency is found by response surface methodology, where the temperature rates and the carrier gas velocities are systematically varied in the experiments. A second model that accurately explains the retention time of the last eluting compound can be found from the same experiments, and optimal conditions are found by combining the two models. The methodology has been evaluated with four capillary columns and three carrier gases, using fatty acid methyl esters as analytes. All experiments showed that there is a fairly linear decrease in efficiency with increasing temperature rates. At any temperature rate, optimal velocity is only marginally higher than the velocity that maximises chromatographic efficiency, since the carrier gas velocity has a limited effect on the retention times.
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Affiliation(s)
- Svein A Mjøs
- Department of Chemistry, University of Bergen, Bergen, Norway
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13
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Lin CC, Wasta Z, Mjøs SA. Evaluation of the retention pattern on ionic liquid columns for gas chromatographic analyses of fatty acid methyl esters. J Chromatogr A 2014; 1350:83-91. [DOI: 10.1016/j.chroma.2014.05.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 05/04/2014] [Accepted: 05/08/2014] [Indexed: 11/28/2022]
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14
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Chhaganlal M, Skartland LK, Mjøs SA. Transfer of retention patterns in gas chromatography by means of response surface methodology. J Chromatogr A 2014; 1332:64-72. [DOI: 10.1016/j.chroma.2014.01.039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Revised: 01/09/2014] [Accepted: 01/14/2014] [Indexed: 10/25/2022]
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15
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Zeng YX, Mjøs SA, Meier S, Lin CC, Vadla R. Least squares spectral resolution of liquid chromatography–mass spectrometry data of glycerophospholipids. J Chromatogr A 2013; 1280:23-34. [DOI: 10.1016/j.chroma.2012.12.070] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 12/20/2012] [Accepted: 12/26/2012] [Indexed: 11/16/2022]
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Abstract
At conditions commonly applied for trans fatty analyses by gas chromatography, fatty acids naturally occurring in marine lipids may overlap chromatographically with C16 and C18 trans fatty acids and lead to false positives. Elution patterns were studied by tracking retention indices at shifting temperature conditions on two cyanopropyl-coated capillary columns. Most overlaps can be avoided by selecting the right chromatographic conditions, but it was not possible to find a single condition that eliminates the risk of overlap between trans fatty acids and interferents. In total, 17 compounds were identified as potential interferents, and the amounts of these compounds were quantified in various samples of marine origin. The interferents that will most likely contribute to incorrect assessments of trans fatty acids in marine lipids are probably 18:3 n-4 and 18:1 n-11.
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Affiliation(s)
- Svein A Mjøs
- Nofima BioLab, Kjerreidviken 15, N-5141 Fyllingsdalen, Bergen, Norway.
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17
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Zhang L, Mjøs SA, Meier S, Kvalheim OM, Liang Y. The vector of calibration ratios: A simple transfer method for mass spectra. J Chromatogr A 2010; 1217:5986-94. [DOI: 10.1016/j.chroma.2010.07.039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 07/06/2010] [Accepted: 07/14/2010] [Indexed: 11/28/2022]
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Mjøs SA, Grung B. A Rank annihilation approach to reducing the scan-effect in gas chromatography–mass spectrometry data. Anal Chim Acta 2009; 640:33-9. [DOI: 10.1016/j.aca.2009.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2008] [Accepted: 03/05/2009] [Indexed: 10/21/2022]
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Mjøs SA. Retention behavior oftrans isomers of eicosapentaenoic and docosahexaenoic acid methyl esters on a polyethylene glycol stationary phase. EUR J LIPID SCI TECH 2008. [DOI: 10.1002/ejlt.200700225] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Boitsov S, Mjøs SA, Meier S. Identification of estrogen-like alkylphenols in produced water from offshore oil installations. Mar Environ Res 2007; 64:651-65. [PMID: 17714776 DOI: 10.1016/j.marenvres.2007.07.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Revised: 06/28/2007] [Accepted: 07/02/2007] [Indexed: 05/16/2023]
Abstract
Produced water released into the sea from oil installations contains a vast number of organic compounds. This work focuses on the analysis and identification of phenols in produced water, in particular long-chain para-substituted alkylphenols, which act as endocrine disruptors for marine biota. Some alkylphenol standards, unavailable commercially, have been synthesised and some compounds of interest identified. However, a complete identification is not possible since conventional GC techniques cannot achieve the desired degree of separation. An overview of the levels of the 52 known alkylphenols in produced water from nine oil installations in the North and Norwegian Seas has been made. The previously unidentified alkylphenols in produced water have been characterised by means of alkylphenol retention indices (APRI) and mass spectrometry, and their total amounts estimated for the same nine locations. Our results confirm the presence of naphthols and other as yet unidentified compounds in produced water, while thiophenols were not detected by the used technique.
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Abstract
A novel type of retention indices for alkylphenols and related compounds are proposed. The alkylphenol retention indices (APRI) use para-substituted n-alkylphenols as reference series. APRI for para-n-alkylphenols are per definition equal to the number of carbon atoms in the alkyl substituent; the value for phenol is zero. Application of the APRI system with different types of derivatisation of the phenolic hydroxy group showed that the derivatisation has limited influence on these indices. Especially para-substituted alkylphenols gave APRI values that could be transferred with high accuracy from one type of derivative to another. By comparing results obtained with different gradients in temperature-programmed GC, it was also shown that APRI is less affected by chromatographic conditions than retention indices based on n-alkanes.
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Affiliation(s)
- Svein A Mjøs
- Norwegian Institute of Fisheries and Aquaculture Research, Bergen, Norway
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Mjøs SA. Prediction of equivalent chain lengths from two-dimensional fatty acid retention indices. J Chromatogr A 2006; 1122:249-54. [PMID: 16701676 DOI: 10.1016/j.chroma.2006.04.067] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Revised: 04/20/2006] [Accepted: 04/25/2006] [Indexed: 10/24/2022]
Abstract
A recently introduced two-dimensional fatty acid retention index system (2D-FARI) was used as basis for prediction of equivalent chain lengths (ECL) of fatty acid methyl esters (FAME) on a BPX-70 stationary phase. Models for the relationship between 2D-FARI data and ECL values of a calibration sample with 30 common fatty acids were established by a simple multivariate regression. The models were thereafter applied on 2D-FARI data for other FAMEs and used to predict the ECLs for these compounds. The 2D-FARI values for the fatty acids in the calibration sample are given by definition. Thus, the only information necessary to calculate the ECL value for a compound run under identical conditions as the calibration sample is the 2D-FARI values for the compound, which can be acquired from literature data. The method was validated with test sets analysed with different temperature and flow programs. ECLs of various marine FAME and trans isomers of Eicosapentaenoic and Docosahexaenoic acid were predicted with root mean squared error of prediction from 0.002 to 0.012 ECL units.
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Affiliation(s)
- Svein A Mjøs
- Norwegian Institute of Fisheries and Aquaculture Research, Department SFF, Kjerreidviken 16, N-5141 Fyllingsdalen, Bergen, Norway.
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Mjøs SA, Meier S, Grahl-Nielsen O. Geometrical isomerisation of double bonds in acid-catalysed preparation of fatty acid methyl esters. EUR J LIPID SCI TECH 2006. [DOI: 10.1002/ejlt.200500298] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Mjøs SA, Grahl-Nielsen O. Prediction of gas chromatographic retention of polyunsaturated fatty acid methyl esters. J Chromatogr A 2006; 1110:171-80. [PMID: 16460747 DOI: 10.1016/j.chroma.2006.01.092] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 01/17/2006] [Accepted: 01/19/2006] [Indexed: 11/26/2022]
Abstract
Multivariate regression models were applied to predict retention indices as equivalent chain lengths (ECL) for methylene-interrupted polyunsaturated fatty acids. Simple molecular descriptors, the chain length, the number of double bonds and the position of the double bond system, were used as predictors. The merits of different variable combinations were evaluated. For general models, it was necessary to include the distance from the double bond system to both the carbonyl group (Delta-position) and the methyl end of the fatty acid (n-position). The best accuracy was found for models including higher order terms of Delta and n. For models restricted to n-3 and n-6 isomers, it was not necessary to include the n-position among the variables. The highest residuals for the most accurate models were below 0.06 ECL units, and root mean square error of prediction was below 0.030. The ECL data was achieved by three different temperature programs on a cyanopropyl column.
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Affiliation(s)
- Svein A Mjøs
- Fiskeriforskning, Kjerreidviken 16, N-5141 Fyllingsdalen, Norway.
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Meier S, Mjøs SA, Joensen H, Grahl-Nielsen O. Validation of a one-step extraction/methylation method for determination of fatty acids and cholesterol in marine tissues. J Chromatogr A 2006; 1104:291-8. [PMID: 16343517 DOI: 10.1016/j.chroma.2005.11.045] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2005] [Revised: 11/08/2005] [Accepted: 11/14/2005] [Indexed: 11/21/2022]
Abstract
A simple and fast direct extraction/methylation with methanolic hydrogen chloride was validated for determination of fatty acids (FA) in marine tissues. Three parameters: reaction time, temperature and presence of non-polar solvent, were studied by an experimental 2(3) full factorial design. The method was validated for five different types of samples; cod liver (high lipid content >60%, mainly triacylglycerol), cod muscle (low lipid content, approximately 1%, mainly phospholipids), cod plasma (lipid content, approximately 2%, mainly lipoprotein complex, high water amount), cod testis (lipid content approximately 3%, high levels of cholesterol), and herring muscle (lipid content approximately 7%). The one-step procedure for extraction/methylation of wet tissues was compared with the traditional procedure of extraction of the lipids by the Folch method (chloroform/methanol, 2:1, v/v), followed by methylation. The two methods gave similar FA profiles. The one-step extraction/methylation procedure gave a higher recovery of the total FA than the traditional procedure. Problems with carry-over peaks of cholesterol from previous samples were avoided by application of extra long GC temperature programs. The cholesterol decomposed to some degree under the preceding methanolysis step, giving several peaks in the chromatograms. The decomposition peaks were identified by mass spectrometry as cholestdienes originating from dehydration of cholesterol, a metylether of cholesterol and a cholesteryl chloride. These cholesterol artefacts can be used for quantitative determination of cholesterol in the samples. Standard samples of cholesterol were determined with high accuracy, (R(2)>0.99), and cholesterol in cod plasma was compared with good agreement (R(2)=0.97) to an enzymatic method.
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Affiliation(s)
- Sonnich Meier
- Institute of Marine Research, P.O. Box 1870, Nordnes, 5817 Bergen, Norway.
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Mjøs SA. Properties of trans isomers of eicosapentaenoic acid and docosahexaenoic acid methyl esters on cyanopropyl stationary phases. J Chromatogr A 2005; 1100:185-92. [PMID: 16236287 DOI: 10.1016/j.chroma.2005.09.079] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2005] [Revised: 09/19/2005] [Accepted: 09/23/2005] [Indexed: 11/24/2022]
Abstract
The trans isomers of 5,8,11,14,17-eicosapentaenoic acid (EPA) and 4,7,10,13,16,19-docosahexaenoic acid (DHA) methyl esters were prepared by isomerisation with paratoluenesulfinic acid (PTSA) in dioxane. The isomers were fractionated by silver ion liquid chromatography with baseline resolution between the isomers with different number of trans double bonds. The fractions were analysed by GC-MS and the gas chromatographic properties of the EPA and DHA isomers with one and two trans double bonds were investigated on BPX-70 and SP-2560 cyanopropyl stationary phases. Different temperature and pressure programs were applied to introduce variations in retention indices of the isomers. The retention indices of all the trans isomers showed a strong linear correlation to the retention indices of the equivalent all-cis isomer, but the slopes for corresponding linear regression lines varied with the number of trans double bonds in the molecule. The regression lines were used to predict optimal conditions for the separation of trans isomers from the corresponding all-cis isomers. For DHA on BPX-70, and for EPA on both columns, it was possible to find windows where isomers with one trans double bond can be resolved from the corresponding all-cis isomers with R(s) > 1.0. In general, BPX-70 seems to have a more suitable selectivity for the analysis of these isomers than SP-2560. Two-dimensional fatty acid retention indices (2D-FARI) were found to be suitable for identification of trans geometry in polyunsaturated fatty acids (PUFA). Although there were substantial overlaps in the range of retention times between the all-cis isomers and isomers with one and two trans double bonds, 2D-FARI separated the isomers into distinct groups according to the number of trans double bonds.
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Affiliation(s)
- Svein A Mjøs
- Norwegian Institute of Fisheries and Aquaculture Research, Department SFF, Fyllingsdalen, Bergen, Norway.
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Abstract
A two-dimensional retention index system for fatty acid methyl esters (2D-FARI) is proposed. The system is based on the application of different temperature and pressure programs on a single capillary column. A calibration sample is analysed and the retention data is calibrated against a set of reference 2D-FARI values. The calibration models are then applied to predict the 2D-FARI values for compounds that are not present in the calibration sample. The two dimensions in the retention index system lead to increased selectivity and a reduced risk of retention index overlap between different compounds. The 2D-FARI system is also more robust towards differences in stationary phase properties than ordinary retention indices and is therefore convenient for comparison of retention data acquired on different columns, or at different times at the same column.
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Affiliation(s)
- Svein A Mjøs
- Norwegian Institute of Fisheries and Aquaculture Research, Kjerreidviken 16, N-5141 Fyllingsdalen, Norway.
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Mjøs SA. The prediction of fatty acid structure from selected ions in electron impact mass spectra of fatty acid methyl esters. EUR J LIPID SCI TECH 2004. [DOI: 10.1002/ejlt.200401013] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Mjøs SA. Quantification of linolenic acid isomers by gas chromatography-mass spectrometry and deconvolution of overlapping chromatographic peaks. EUR J LIPID SCI TECH 2004. [DOI: 10.1002/ejlt.200300909] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Mjøs SA. Identification of fatty acids in gas chromatography by application of different temperature and pressure programs on a single capillary column. J Chromatogr A 2003; 1015:151-61. [PMID: 14570328 DOI: 10.1016/s0021-9673(03)01240-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A method for the identification of fatty acid methyl esters (FAME) based on the analysis of shifts in equivalent chain lengths (ECL) is described. The method is based on two-dimensional retention data achieved on one capillary column. Various temperature and pressure programs are applied on the same cyanopropyl column and the shifts in the ECL values are analysed by multivariate methods. The chain length, number of double bonds, and the double bond positions can be determined with high accuracy. The same procedure is suitable for determination of the number of trans and cis double bonds in trans fatty acids, and for detection of artefacts in fatty acid methyl ester chromatograms.
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Affiliation(s)
- Svein A Mjøs
- Norwegian Institute of Fisheries and Aquaculture Research, Kjerreidviken 16, N-5141 Fyllingsdalen, Norway.
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Nenseter MS, Østerud B, Larsen T, Strøm E, Bergei C, Hewitt S, Holven KB, Hagve TA, Mjøs SA, Solvang M, Pettersen J, Opstvedt J, Ose L. Effect of Norwegian fish powder on risk factors for coronary heart disease among hypercholesterolemic individuals. Nutr Metab Cardiovasc Dis 2000; 10:323-330. [PMID: 11302007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
BACKGROUND AND AIM Numerous studies suggest an association between high intake of fatty fish and reduced risk of coronary heart disease. Very long-chain omega-3 fatty acids are thought to be responsible for the benefits observed, though other fatty fish components may act in concert with them. Norwegian fish powder is a dry herring product that contains essential amino acids, marine omega-3 fatty acids, vitamins and minerals. The aim of the present study was to determine whether it has beneficial effects on risk factors for coronary heart disease in man. METHODS AND RESULTS A single center, randomized, double-blind, parallel-treatment study was carried out for 12 weeks. Subjects with primary hypercholesterolemia were randomly allocated to 10 g fish powder or placebo (20 tablets/day). Participants were instructed to follow National Cholesterol Education Program (NCEP) Step I Diet during a 4-week diet run-in phase and during the study. Concentrations of lipids, lipoproteins, hemostatic variables and endothelial cell markers were determined before and after supplementation. Our data showed that the fish powder supplement was well tolerated. A significant decrease and increase respectively were observed in plasma alpha-linolenic acid (p = 0.03) and docosahexaenoic acid (DHA) (p = 0.03). Concentrations of lipids, lipoproteins, homocysteine, factor VII, fibrinogen, tissue plasminogen activator (tPA), plasminogen activator inhibitor (PAI)-1, soluble intercellular adhesion molecule (ICAM)-1, P-selectin and interleukin (IL)-8 were not beneficially affected. CONCLUSIONS Fish powder supplementation does not seem an effective approach to improve risk factors for coronary heart disease in hypercholesterolemic subjects following the NCEP Step I Diet.
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Affiliation(s)
- M S Nenseter
- Lipid Clinic, University of Oslo, Rikshospitalet, 0027 Oslo, Norway
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