A routine method for the simultaneous measurement of retinol, α-tocopherol and five carotenoids in human plasma by reverse phase HPLC

Talwar, Dinesh; Ha, Thomas; Cooney, Josephine; Brownlee, Christine; JO’Reilly, Denis St.

doi:10.1016/s0009-8981(97)00224-6

Cited by 180 publications

(154 citation statements)

References 17 publications

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“…27 Briefly, plasma was deproteinized with alcohol containing internal standards and extraction of the analytes of interest was performed using hexane. Analysis was carried out using reversed-phase HPLC (5 lm microbore, Phenomenex, Macclesfield, UK) and dual wavelength monitoring (Waters, MA).…”

Section: Laboratory Measurementsmentioning

confidence: 99%

Vitamin antioxidants, lipid peroxidation, tumour stage, the systemic inflammatory response and survival in patients with colorectal cancer

Leung

Crozier

Talwar

et al. 2008

Intl Journal of Cancer

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Both the tumour growth and progression and the systemic inflammatory response have the potential to increase oxidative stress. We therefore examined the relationship between lipid-soluble antioxidant vitamins, lipid peroxidation, the systemic inflammatory response and survival in patients with primary operable (n 5 53) and advanced inoperable (n 5 53) colorectal cancer. Compared with those patients with primary operable colorectal cancer, patients with unresectable liver disease had significantly lower median concentrations of a-tocopherol (p < 0.001), lutein (p < 0.001), lycopene (p < 0.001), a-carotene (p < 0.01) and b-carotene (p < 0.001) and higher malondialdehyde concentrations. An elevated systemic inflammatory response (Glasgow prognostic score, mGPS) was associated with a greater proportion of females (p < 0.05) and more advanced tumour stage (p < 0.05), lower circulating levels of retinol (p < 0.01), lutein (p < 0.01), lycopene (p < 0.01) and a-(p < 0.01) and b-carotene but not MDA (p 5 0.633). In the liver metastases group 41 patients died of their cancer and a further 1 patient died of intercurrent disease on follow-up. On univariate survival analysis, mGPS (p < 0.01), retinol (p < 0.001), atocopherol (p < 0.05) and a-carotene (p < 0.05) were associated significantly with cancer-specific survival. On multivariate survival analysis of these significant variables, only mGPS (p < 0.01) and retinol (p < 0.001) were independently associated with cancer-specific survival. The results of the present study showed that the systemic inflammatory response was associated with a reduction of lipid-soluble antioxidant vitamins, whereas advanced tumour stage was associated with increased lipid peroxidation in patients with colorectal cancer. Of the antioxidant vitamins measured, only retinol was independently associated with cancer-specific survival. ' 2008 Wiley-Liss, Inc.Key words: colorectal cancer; vitamin A; vitamin E; carotenoids; malonyldialdehyde; TNM stage; Glasgow prognostic score; survival Colorectal cancer remains the second commonest cause of cancer deaths in Western Europe and North America. Each year in the United Kingdom, there are 35,000 new cases and 16,000 deaths attributable to the disease.1 Overall survival is poor; even in those patients who undergo potentially curative resection, more than one-third die within 5 years. It is increasingly recognised that variations in outcome in cancer patients are not solely determined by the characteristics of the tumour but also by host-immune response factors. [3][4][5] It is now accepted that the host systemic inflammatory response can be assessed by examining the changes in the circulating concentrations of acute-phase proteins, such as an elevated concentration of C-reactive protein and a low concentrations of albumin 6 and that these have prognostic values in patients with cancer. 7,8 Recently, the combination of C-reactive protein and albumin, known as the Glasgow prognostic score (GPS), has been validated as a prognostic factor in patients with color...

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Section: Laboratory Measurementsmentioning

confidence: 99%

Vitamin antioxidants, lipid peroxidation, tumour stage, the systemic inflammatory response and survival in patients with colorectal cancer

Leung

Crozier

Talwar

et al. 2008

Intl Journal of Cancer

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“…Plasma retinol (vitamin A), ␣-tocopherol (vitamin E), and the carotenoids lutein, lycopene, ␣-carotene, and ␤-carotene were assayed by isocratic reversed-phase HPLC method using ultraviolet detection as described previously (13 ). Our laboratory uses plasma from a single donor, which is aliquoted and stored at Ϫ70°C, as an in-house quality-control material for these analytes because a suitable commercial preparation is unavailable.…”

Section: Vitamins a And E And Carotenoidsmentioning

confidence: 99%

Biological Variation of Vitamins in Blood of Healthy Individuals

et al. 2005

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Background: Components of biological variation can be used to define objective quality specifications (imprecision, bias, and total error), to assess the usefulness of reference values [index of individuality (II)], and to evaluate significance of changes in serial results from an individual [reference change value (RCV)]. However, biological variation data on vitamins in blood are limited. The aims of the present study were to determine the intra-and interindividual biological variation of vitamins A, E, B 1 , B 2 , B 6 , C, and K and carotenoids in plasma, whole blood, or erythrocytes from apparently healthy persons and to define quality specifications for vitamin measurements based on their biology. Methods: Fasting plasma, whole blood, and erythrocytes were collected from 14 healthy volunteers at regular weekly intervals over 22 weeks. Vitamins were measured by HPLC. From the data generated, the intra-(CV I ) and interindividual (CV G ) biological CVs were estimated for each vitamin. Derived quality specifications, II, and RCV were calculated from CV I and CV G . Results: CV I was 4.8%-38% and CV G was 10%-65% for the vitamins measured. The CV I s for vitamins A, E, B 1 , and B 2 were lower (4.8%-7.6%) than for the other vitamins in blood. For all vitamins, CV G was higher than CV I , with II <1.0 (range, 0.36 -0.95). The RCVs for vitamins were high (15.8%-108%). Apart from vitamins A, B 1 , and erythrocyte B 2 , the imprecision of our methods for measurement of vitamins in blood was within the desirable goal. Conclusions: For most vitamin measurements in plasma, whole blood, or erythrocytes, the desirable imprecision goals based on biological variation are

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“…Thus the development of a suitable method for simultaneous measurements of all of the lipophilic antioxidants, including the tocotrienols, became a challenge. To overcome autooxidation of lipid-soluble vitamins and carotenoids during sample treatment, BHT (9 -12 ) or ascorbic acid (8 ) has been added routinely as an antioxidative preservative. However, we found that BHT was more suitable than ascorbic acid when tocopherols were determined by ultraviolet detection at 292 nm.…”

Section: Tocopherol and Tocotrienol Analysismentioning

confidence: 99%

Simultaneous Determination of Tocotrienols, Tocopherols, Retinol, and Major Carotenoids in Human Plasma

2003

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Background: Epidemiologic evidence suggests that the concentrations of antioxidant vitamins in human plasma may play an important role in numerous chronic diseases, such as cancer and cardiovascular disease. However, methods for simultaneous measurement of these antioxidants are scarce. We developed and validated a new HPLC method for simultaneous determination of these vitamers in human plasma that uses a novel column-switching approach. Methods:The new method uses liquid-liquid extraction and isocratic separation with two monomeric C 18 columns maintained at 35 and 4°C coupled with ultraviolet-visible and fluorometric detection. This method could separate 14 vitamers and 3 internal standards within 27 min. No additional modifier was required; the mobile phase was acetonitrile-methanol (65:35 by volume), and the flow rate was 1 mL/min. Results: For photodiode array detection, the detection limits (signal-to-noise ratio >3) were 0.02 mg/L for ␤-carotene, lutein, zeaxanthin, and canthaxanthin; 0.01 mg/L for all-trans-retinol, ␤-cryptoxanthin, ␣-carotene, and lycopene; and 0.1 mg/L for all tocopherols and tocotrienols. The detection limit was at least 25-fold lower (0.004 mg/L) when fluorometry was used for measurement of ␦-, ␥-, and ␣-tocotrienol and ␦-tocopherol compared with ultraviolet detection. The recovery and imprecision of the assay were generally >90% and <10%, respectively. Conclusions: This new method separates a wide range of fat-soluble antioxidant vitamins in human plasma, including six carotenoids, three isoforms of tocotrienols and tocopherols (␦-, ␥-, and ␣-), and all-trans-retinol. The overall findings suggest that our method is faster,

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A routine method for the simultaneous measurement of retinol, α-tocopherol and five carotenoids in human plasma by reverse phase HPLC

Cited by 180 publications

References 17 publications

Vitamin antioxidants, lipid peroxidation, tumour stage, the systemic inflammatory response and survival in patients with colorectal cancer

Vitamin antioxidants, lipid peroxidation, tumour stage, the systemic inflammatory response and survival in patients with colorectal cancer

Biological Variation of Vitamins in Blood of Healthy Individuals

Simultaneous Determination of Tocotrienols, Tocopherols, Retinol, and Major Carotenoids in Human Plasma

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