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Effects of fish oil supplementation on eicosanoid production in patients at higher risk for colorectal cancer. Eur J Cancer Prev 2019; 28:188-195. [PMID: 30640206 DOI: 10.1097/cej.0000000000000455] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Fish oil supplementation may represent a potential chemopreventive agent for reducing colorectal cancer risk. The mechanism of action of fish oil is unknown but presumed to be related to eicosanoid modification. The purpose of this study was to evaluate the effects of fish oil supplementation on the levels of urinary and rectal eicosanoids. We conducted a randomized, double-blind, controlled trial of 2.5 g of fish oil per day compared with olive oil supplementation over a 6-month period. Study participants had a history of colorectal adenomas. Randomization was stratified based on the gene variant rs174535 in the fatty acid desaturase 1 enzyme (FADS1), which affects tissue levels of arachidonic acid. A total of 141 participants were randomized. Urinary prostaglandin E2 metabolite (PGE-M) was measured at baseline, 3, and 6 months and rectal prostaglandin E2 (PGE2) at baseline and 6 months. Repeated-measures linear regression was used to determine the effect of the intervention on each outcome measure. Overall, fish oil supplementation was found to reduce urinary PGE-M production compared with olive oil (P=0.03). Fish oil did not reduce rectal PGE2 overall; however, it did significantly reduce PGE2 in the subgroup of participants not using aspirin or NSAIDs (P=0.04). FADS1 genotype did not seem to modify effects of fish oil on PGE2 production. We conclude that fish oil supplementation has a modest but beneficial effect on eicosanoids associated with colorectal carcinogenesis, particularly in those not taking aspirin or NSAIDs.
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PUFA levels in erythrocyte membrane phospholipids are differentially associated with colorectal adenoma risk. Br J Nutr 2017; 117:1615-1622. [PMID: 28660850 DOI: 10.1017/s0007114517001490] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Dietary intake of PUFA has been associated with colorectal neoplasm risk; however, results from observational studies have been inconsistent. Most prior studies have utilised self-reported dietary measures to assess fatty acid exposure which might be more susceptible to measurement error and biases compared with biomarkers. The purpose of this study was to determine whether erythrocyte phospholipid membrane PUFA percentages are associated with colorectal adenoma risk. We included data from 904 adenoma cases and 835 polyp-free controls who participated in the Tennessee Colorectal Polyp Study, a large colonoscopy-based case-control study. Erythrocyte membrane PUFA percentages were measured using GC. Conditional logistic regression was used to calculate adjusted OR for risk of colorectal adenomas with erythrocyte membrane PUFA. Higher erythrocyte membrane percentages of arachidonic acid was associated with an increased risk of colorectal adenomas (adjusted OR 1·66; 95 % CI 1·05, 2·62, P trend=0·02) comparing the highest tertile to the lowest tertile. The effect size for arachidonic acid was more pronounced when restricting the analysis to advanced adenomas only. Higher erythrocyte membrane EPA percentages were associated with a trend towards a reduced risk of advanced colorectal adenomas (P trend=0·05). Erythrocyte membrane arachidonic acid percentages are associated with an increased risk of colorectal adenomas.
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Murff HJ, Edwards TL. Endogenous Production of Long-Chain Polyunsaturated Fatty Acids and Metabolic Disease Risk. CURRENT CARDIOVASCULAR RISK REPORTS 2014; 8. [PMID: 26392837 DOI: 10.1007/s12170-014-0418-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Long chain polyunsaturated fatty acids (PUFAs) are important structural components of cellular membranes and are converted into eicosanoids which serve various biological roles. The most common dietary n-6 and n-3 PUFAs are linoleic acid and α-linoleic acid, respectively. These 18-carbon chain fatty acids undergo a series of desaturation and elongation steps to become the 20-carbon fatty acids arachidonic acid and eicosapentaenoic acid, respectively. Evidence from genome wide association studies has consistently demonstrated that plasma and tissue levels of the n-6 long-chain PUFA arachidonic acid and to a lesser extent the n-3 long-chain PUFA eicosapentaenoic acid, are strongly influenced by variation in fatty acid desaturase-1,-2, and elongation of very long chain fatty acid genes. Studies of functional variants in these genes, as well as studies in which desaturase activity has been indirectly estimated by fatty acid product-to -precursor ratios, have suggested that endogenous capacity to synthesize long-chain PUFAs may be associated with metabolic diseases such as diabetes mellitus. Interventional studies are starting to tease out the complicated relationship between dietary intakes of specific fatty acids, variation in desaturase and elongase genes and tissue levels of long chain PUFAs. Thus future studies of dietary PUFA interventions designed to reduce inflammatory and metabolic diseases will need to carefully consider how an individual's genetically-determined endogenous long-chain PUFA synthesis capacity might modify therapeutic response.
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Affiliation(s)
- Harvey J Murff
- Division of General Internal Medicine and Public Health, Vanderbilt University School of Medicine, Nashville TN ; GRECC, Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville TN
| | - Todd L Edwards
- Division of Epidemiology, Vanderbilt University School of Medicine
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Yang P, Jiang Y, Fischer SM. Prostaglandin E3 metabolism and cancer. Cancer Lett 2014; 348:1-11. [PMID: 24657656 DOI: 10.1016/j.canlet.2014.03.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2014] [Revised: 03/03/2014] [Accepted: 03/07/2014] [Indexed: 01/13/2023]
Abstract
The anticancer activity of n-3 fatty acids, especially those derived from fish, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid) (DHA), has been studied for centuries. While there is a growing body of evidence that EPA and DHA may influence cancer initiation and development through targeting multiple events of tumor development, the underlying mechanisms responsible for these activities are still not fully understood. A number of studies have suggested that the anticancer activities of EPA and DHA are associated with their effects on eicosanoid metabolism by which they inhibit prostaglandin E2 (PGE2) production. In contrast to DHA, EPA can function as a substrate for cyclooxygenases (COXs) to synthesize unique 3-series prostaglandin compounds, especially PGE3. With advance technology in mass spectrometry, there is renewed interest in studying the role of PGE3 in EPA elicited anti-proliferative activity in various cancers, with some promising results. Here, we summarize the regulation of PGE3 synthesis in cancer cells and its role in EPA elicited anticancer activity. The development of PGE3 and its metabolites as potential biomarkers for future clinical evaluation of EPA and fish oil in cancer care is discussed.
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Affiliation(s)
- Peiying Yang
- Department of General Oncology, The University of Texas, MD Anderson Cancer Center, Houston, TX, United States.
| | - Yan Jiang
- Department of General Oncology, The University of Texas, MD Anderson Cancer Center, Houston, TX, United States
| | - Susan M Fischer
- Department of Molecular Carcinogenesis, The University of Texas, MD Anderson Cancer Center, Houston, TX, United States
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Young LR, Kurzer MS, Thomas W, Redmon JB, Raatz SK. Effect of dietary fat and omega-3 fatty acids on urinary eicosanoids and sex hormone concentrations in postmenopausal women: a randomized controlled feeding trial. Nutr Cancer 2011; 63:930-9. [PMID: 21745038 DOI: 10.1080/01635581.2011.589957] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Substantial evidence relates increased sex hormone concentrations with increased breast cancer risk. Varying omega-3 (n-3) fatty acid (FA) intake may lead to alterations in eicosanoid balance and changes in circulating sex hormones that reduce risk. To clarify effects of dietary fat and n-3 FA intake on breast cancer risk markers, circulating sex hormones and urinary eicosanoids were measured in response to controlled feeding of diets designed to increase plasma concentrations of n-3 FA. A controlled cross-over feeding trial in postmenopausal women was conducted using 3 diets: high fat (HF; 40% energy from fat), low fat (LF; 20% energy from fat), and low fat plus n-3 FA (LFn3; 20% of energy from fat plus 3% of energy from n-3 FA) in 8-wk feeding periods. Plasma phospholipid fatty acid n-3 increased with the LFn3 relative to HF and LF (P < 0.0001). Plasma estradiol increased by 51% with HF (P = 0.03). Urinary prostaglandin E metabolite increased with HF relative to LF (P = 0.02) and urinary 11-dehydro-thromboxane B(2) increased with HF (P = 0.01). These results do not support a role of n-3 FA in the reduction of sex hormone levels.
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Affiliation(s)
- Lindsay R Young
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota, USA
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Harris WS, Poston WC, Haddock CK. Tissue n-3 and n-6 fatty acids and risk for coronary heart disease events. Atherosclerosis 2007; 193:1-10. [PMID: 17507020 DOI: 10.1016/j.atherosclerosis.2007.03.018] [Citation(s) in RCA: 203] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 02/12/2007] [Accepted: 03/13/2007] [Indexed: 11/29/2022]
Abstract
BACKGROUND Tissue proportions of long chain n-6 [especially arachidonic acid (AA)] and n-3 fatty acids [FA; eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) acids], or some ratio of these may be markers of risk for coronary heart disease (CHD). The purpose of this paper is to evaluate the published associations between risk for CHD events and tissue n-3 and n-6 FA composition. METHODS Case-control or prospective cohort data sets examining the risk for CHD endpoints as a function of tissue FA composition were identified. Effect sizes were computed for case versus control comparisons using standard meta-analytic methods. RESULTS Twenty-five studies were included, 18 examining the FA composition of phospholipid-rich and 7 of triglyceride-rich samples. DHA, with or without EPA, was significantly lower in cases than controls in all studies combined, in those with fatal endpoints, in those with prospective designs, and in both tissue types. The only setting where increased AA was associated with case status was in adipose tissue. The AA/EPA ratio in phospholipid-rich samples did not distinguish cases from controls. Lower linoleic acid content was associated with increased risk for non-fatal events. CONCLUSIONS The long-chain n-3 FA, especially DHA, were consistently and significantly reduced in patients experiencing CHD events. These findings add further support to the view that long-chain n-3 FA are cardioprotective.
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Affiliation(s)
- William S Harris
- Sanford School of Medicine, University of South Dakota, Sioux Falls, SD, United States.
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Abstract
The protein loss in humans during spaceflight is partly due to a normal adaptive response to a decreased work load on the muscles involved in weight bearing. The process is mediated by changes in prostaglandin release, secondary to the decrease in tension on the affected muscles. On missions, where there is a high level of physical demands on the astronauts, there tends to be an energy deficit, which adds to the muscle protein loss and depletes the body fat reserves. While the adaptive response is a normal part of homeostasis, the additional protein loss from an energy deficit can, in the long run, have a negative effect on health and capability of humans to live and work in space and afterward return to Earth.
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Affiliation(s)
- T P Stein
- Department of Surgery, University of Medicine and Dentistry of New Jersey, Stratford, USA
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Stein TP, Schluter MD, Moldawer LL. Endocrine relationships during human spaceflight. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:E155-62. [PMID: 9886962 DOI: 10.1152/ajpendo.1999.276.1.e155] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Human spaceflight is associated with a chronic loss of protein from muscle. The objective of this study was to determine whether changes in urinary hormone excretion could identify a hormonal role for this loss. Urine samples were collected from the crews of two Life Sciences Space Shuttle missions before and during spaceflight. Data are means +/- SE with the number of subjects in parentheses. The first value is the mean preflight measurement, and the second value is the mean inflight measurement. Adrenocorticotropic hormone (ACTH) [27.7 +/- 4.4 (9) vs. 25.1 +/- 3.4 (9) ng/day], growth hormone [724 +/- 251 (9) vs. 710 +/- 206 (9) ng/day], insulin-like growth factor I [6.81 +/- 0.62 vs. 6.04 +/- 0.51 (8) nM/day], and C-peptide [44.9 +/- 8.3 (9) vs. 50.7 +/- 10.3 (9) micrograms/day] were unchanged with spaceflight. In contrast, free 3,5,3'-triiodothyronine [791 +/- 159 (9) vs. 371 +/- 41 (9) pg/day, P < 0.05], prostaglandin E2 (PGE2) [1, 064 +/- 391 (8) vs. 465 +/- 146 (8) ng/day, P < 0.05], and its metabolite PGE-M [1,015 +/- 98 (9) vs. 678 +/- 105 (9) ng/day, P < 0. 05] were decreased inflight. The urinary excretion of most hormones returned to their preflight levels during the postflight period, with the exception of ACTH [47.5 +/- 10.3 (9) ng/day], PGE2 [1,433 +/- 327 (8) ng/day], PGF2alpha, [2,786 +/- 313 (8) ng/day], and its metabolite PGF-M [4,814 +/- 402 (9) ng/day], which were all increased compared with the preflight measurement (P < 0.05). There was a trend for urinary cortisol to be elevated inflight [55.3 +/- 5. 9 (9) vs. 72.5 +/- 11.1 micrograms/day, P = 0.27] and postflight [82.7 +/- 8.6 (8) micrograms/day, P = 0.13]. The inflight human data support ground-based in vitro work showing that prostaglandins have a major role in modulating the changes in muscle protein content in response to tension or the lack thereof.
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Affiliation(s)
- T P Stein
- Department of Surgery, University of Medicine and Dentistry of New Jersey, School of Osteopathic Medicine, Stratford, New Jersey 08084, USA
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Ferretti A, Nelson GJ, Schmidt PC, Kelley DS, Bartolini G, Flanagan VP. Increased dietary arachidonic acid enhances the synthesis of vasoactive eicosanoids in humans. Lipids 1997; 32:435-9. [PMID: 9113633 DOI: 10.1007/s11745-997-0057-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Data on the effect of dietary arachidonic acid (AA) (20:4n-6) on the synthesis of thromboxane and prostacyclin (PGI2) in humans are lacking. We measured the effect of 1.5 g/d (ca. 0.5 en%) of 20:4n-6 added isocalorically to a stabilization (low-AA) diet on the excretion of 11-dehydrothromboxane B2 (11-DTXB2) and 2,3-dinor-6-oxo-PGF1 alpha (PGI2-M). In a crossover design, 10 healthy men, living in a metabolic unit, were fed a diet (low-AA) containing 210 mg/d of 20:4n-6 for 65 d and an identical diet (high-AA) that contained 1.5 g/d of additional 20:4n-6 for 50 d. Three-day urine pools were collected at the end of each dietary period and analyzed for eicosanoids by gas chromatography-electron capture negative ion-tandem mass spectrometry. Mean excretion of 11-dehydrothromboxane B2 was 515 +/- 76, 493 +/- 154, and 696 +/- 144 ng/d (SD; n = 10) during the acclimation (15 d) low-AA diet and high-AA diet periods, respectively (41% increase from low-AA to high-AA diet, P = 0.0037); mean excretion of PGI2-M was 125 +/- 40, 151 +/- 36, and 192 +/- 55 ng/d (SD; n = 10) during acclimation (15 d) low-AA and high-AA diets; P = 0.0143). Thus both the metabolites of thromboxane and PGI2 increase on the high-AA diet. Furthermore, both indicated changes in metabolite excretion may be associated with measurable effects on several physiologically significant cellular functions, such as platelet aggregation in vivo and inflammation in response to immune challenges.
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Affiliation(s)
- A Ferretti
- Nutrient Requirements and Functions Laboratory, Beltsville Human Nutrition Research Center, USDA, ARS, Maryland 20705, USA
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Ferretti A, Meydani SN, Lichtenstein AH, Flanagan VP, Schaefer EJ. Prostaglandin E metabolite excretion in normolipidemic subjects is lowered by a moderate reduction of n-6/n-3 polyunsaturate ratio and total fat intake. Nutr Res 1994. [DOI: 10.1016/s0271-5317(05)80378-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ferretti A, Flanagan VP. Assay of urinary 2,3-dinor-6-oxo prostaglandin F1α by gas chromatography—tandem mass spectrometry. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/0378-4347(93)80256-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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FERRETTI A, FLANAGAN V, JUDD J, NAIR P, TAYLOR P. Fish oil supplementation reduces excretion of 2,3-dinor-6-oxo-PGF1α and the 11-dehydrothromboxane B2/2,3-dinor-6-oxo-PGF1α excretion ratio in adult men☆. J Nutr Biochem 1993. [DOI: 10.1016/0955-2863(93)90109-a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Abstract
Human immunodeficiency virus (HIV), is able to replicate in many human cells such as helper lymphocytes, monocytes/macrophages and glial cells. Monocytes/macrophages must be considered an important reservoir of HIV in vivo and a producer of cytokines such as Interleukin-1 (IL1) and tumor necrosis factor (TNF). These substances lead to an autocrine feedback loop that produces an increased virus replication and a secondary induction of other cytokines such as Interleukin 6 (IL6) and granulocyte-macrophage colony stimulating factor (GM-CSF). These cytokines all together may be responsible for many clinical aspects of the disease such as headache, fever, anorexia, subtle cognitive changes, motor disfunctions and cachexia. The future strategies in the treatment of AIDS must be a combination of drugs acting on different points of viral replication and with synergistic potential. Omega 3 polyunsaturated fatty acids (omega-3) can be considered a candidate for their pleiotropic effects on immunological and metabolic systems. In particular, their use is considered for their ability to decrease IL1 and TNF production by monocytes/macrophages, as demonstrated by many authors. The decreased induction of these cytokines and consequently of IL6 and acute phase proteins may have beneficial effects on many clinical manifestations of AIDS such as cachexia.
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Affiliation(s)
- E Razzini
- Department of Infectious Diseases, IRCCS Pol San Matteo, University of Pavia, Italy
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Ferretti A, Judd JT, Taylor PR, Nair PP, Flanagan VP. Ingestion of marine oil reduces excretion of 11-dehydrothromboxane B2, an index of intravascular production of thromboxane A2. Prostaglandins Leukot Essent Fatty Acids 1993; 48:305-8. [PMID: 8497491 DOI: 10.1016/0952-3278(93)90220-q] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We evaluated the effect of anchovy oil supplementation on the endogenous production of thromboxane A2 by measuring the excretion of its stable metabolite, 11-dehydrothromboxane B2 (11-DTXB2), in 24-h urine. In a longitudinal study, 35 male volunteers consumed a controlled basal diet for two experimental periods lasting a total of 20 weeks. During period 1 (10 weeks) the diet was supplemented with placebo (PO) capsules (15 x 1 g/d) consisting of a blend of fats approaching the fatty acid profile of the basal diet. During period 2 the subjects received 15 x 1 g/d capsules of fish oil concentrate (FOC). PO and FOC capsules contained 1 mg alpha-tocopherol per gram of fat as antioxidant. A 38% reduction of 11-DTXB2 excretion was observed after 10 weeks of FOC supplementation (period 2, n-6/n-3 PUFA ratio = 2.3), compared to an identical period of PO supplementation (period 1, n-6/n-3 = 12.5), p = 0.0001. The 11-DTXB2 excretion reduction (delta) fits the quadratic equation delta = 136.0038-0.3178(tx1)-0.0002(tx1)2, (R2 = 0.8944), where tx1 is the excretion rate at the end of period 1. This finding supports the hypothesis that the antithrombotic effect of marine oil is mediated, at least in part, by diet-induced shifts in the eicosanoid system.
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Affiliation(s)
- A Ferretti
- Beltsville Human Nutrition Research Center, Lipid Nutrition Laboratory, USDA, MD 20705
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Ferretti A, Flanagan VP. Daughter ion mass spectra of 11-pentafluorobenzyl ester derivatives of 11-dehydiothromboxane B2 and B3. ACTA ACUST UNITED AC 1992. [DOI: 10.1002/oms.1210271130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ferretti A, Flanagan VP, Maida EJ. GC/MS/MS quantification of 11-dehydrothromboxane B2 in human urine. Prostaglandins Leukot Essent Fatty Acids 1992; 46:271-5. [PMID: 1409763 DOI: 10.1016/0952-3278(92)90034-g] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A fully validated stable isotope dilution method for rapid quantification of 11-dehydrothromboxane B2 by gas chromatography/negative chemical ionization tandem mass spectrometry is reported. The interassay coefficient of variation was 1.3%. The relative recovery of synthetic, underivatized 11-dehydrothromboxane B2 added to urine was 84.6 +/- 2.5% (mean +/- SEM, N = 9). The equation of the regression plot correlating the amounts added and recovered was Y = 0.894X-0.23, with R = 0.9963. The late introduction of the pentafluorobenzyl moiety at C11 afforded distinct advantages in the cleanup stage of the assay and during the GC/MS analysis as well. The pair of daughter fragments at m/z 345 and 349 of the parent fragment ions at m/z 615 and 619 were monitored. Excretion values of 11-dehydrothromboxane B2 in 3 healthy male subjects were 975, 615 and 822 ng/24 h. Excretion was reduced to 751, 387 and 465 ng/24 h, respectively, after administration of a fish oil supplement (15 g/day) for 10 weeks.
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Affiliation(s)
- A Ferretti
- Beltsville Human Nutrition Research Center, Lipid Nutrition Laboratory, MD 20705
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Clevidence BA, Ballard-Barbash R. Tocopherol contents of lipoproteins from frozen plasma separated by affinity chromatography. Lipids 1991; 26:723-8. [PMID: 1762518 DOI: 10.1007/bf02535621] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We investigated whether freezing and storage of plasma altered alpha-tocopherol levels of whole plasma or the lipoprotein fractions derived from such plasma. Plasma from 24 men, at each of two collection periods, was frozen at -20 degrees C for six weeks, then high-density lipoproteins (HDL) were separated from low- plus very low-density lipoproteins (LDL-VLDL) by heparin affinity chromatography. Whole plasma and the lipoprotein fractions were analyzed for alpha-tocopherol content and compared to counterparts from fresh plasma. Freezing and storage did not reduce alpha-tocopherol levels of plasma or the lipoprotein fractions. alpha-Tocopherol values from fresh and frozen plasma were highly correlated for both plasma (period 1, r = 0.94; period 2, r = 0.93) and the LDL-VLDL fractions (periods 1 and 2, r = 0.97). Percent distribution of alpha-tocopherol between the two lipoprotein fractions was comparable for lipoproteins derived from fresh and frozen plasma. Under the storage conditions used in this study, plasma can be frozen for at least six weeks prior to lipoprotein fractionation with no detectable detrimental effects on alpha-tocopherol content of either plasma or lipoproteins.
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Affiliation(s)
- B A Clevidence
- Lipid Nutrition Laboratory, Beltsville Human Nutrition Research Center, Maryland 20705
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