A stable isotope dilution LC–ESI-MS/MS method for the quantification of pyridoxal-5′-phosphate in whole blood

Zelst, Bertrand D. van; Jonge, Robert de

doi:10.1016/j.jchromb.2012.07.007

Cited by 15 publications

(14 citation statements)

References 28 publications

(63 reference statements)

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“…We used a 10% solution of TCA for precipitation of proteins in agreement with others [1,3,13]. As PLP is strongly protein bound, a 1 h incubation was needed to liberate PLP from proteins [13].…”

Section: Selection Of Sample Preparation Conditionsmentioning

confidence: 99%

“…When dietary intake is low [1], its concentrations decline rapidly. PLP is a coenzyme in the catabolism of homocysteine and it has a critical role in the treatment of hyperhomocysteinemia [2].…”

Section: Introductionmentioning

confidence: 99%

“…Methods involving derivatization of PLP with semicarbazide [4][5][6], cyanide [7,8], chlorite [2] and bisulfite [9][10][11][12] have been reported. However, LC-MS/MS bioanalytical methods using stable isotope dilution techniques [1,3,13] are preferable because they have high sensitivity and selectivity, and time-consuming derivatization is usually unnecessary.…”

Section: Introductionmentioning

confidence: 99%

“…Other approaches include use of 4% albumin in PBS as matrix [13] or commercially supplied calibrators and QCs [4]. In other work [1], assay calibrators were made in the actual matrix (whole blood) and then corrected for the endogenous PLP concentration (ratio of intercept to slope from the calibration run) to estimate the PLP concentrations in 'unknown' samples. Whole blood samples from individuals with low and high endogenous PLP concentrations were also used as QCs.…”

Section: Introductionmentioning

confidence: 99%

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A novel fully validated LC–MS/MS method for quantification of pyridoxal-5′-phosphate concentrations in samples of human whole blood

Ghassabian

Griffiths

Smith

2015

Journal of Chromatography B

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Quantification of pyridoxal-5'-phosphate (PLP) in biological samples is challenging due to the presence of endogenous PLP in matrices used for preparation of calibrators and quality control samples (QCs). Hence, we have developed an LC-MS/MS method for accurate and precise measurement of the concentrations of PLP in samples (20μL) of human whole blood that addresses this issue by using a surrogate matrix and minimizing the matrix effect. We used a surrogate matrix comprising 2% bovine serum albumin (BSA) in phosphate buffer saline (PBS) for making calibrators, QCs and the concentrations were adjusted to include the endogenous PLP concentrations in the surrogate matrix according to the method of standard addition. PLP was separated from the other components of the sample matrix using protein precipitation with trichloroacetic acid 10% w/v. After centrifugation, supernatant were injected directly into the LC-MS/MS system. Calibration curves were linear and recovery was >92%. QCs were accurate, precise, stable for four freeze-thaw cycles, and following storage at room temperature for 17h or at -80°C for 3 months. There was no significant matrix effect using 9 different individual human blood samples. Our novel LC-MS/MS method has satisfied all of the criteria specified in the 2012 EMEA guideline on bioanalytical method validation.

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Section: Selection Of Sample Preparation Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A novel fully validated LC–MS/MS method for quantification of pyridoxal-5′-phosphate concentrations in samples of human whole blood

Ghassabian

Griffiths

Smith

2015

Journal of Chromatography B

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“…Four studies addressing various samples was conducted on vitamin B complexes [346][347][348][349], a review on folate, vitamin B6 and B12 was conducted on methods for analysis in humans [350], four studies were conducted on vitamin B6 [351][352][353][354], two on folate [355,356], five on vitamin B12 [357][358][359][360][361] and one on betaine (from choline) [362]. These studies have been outlined below in Table 3-2.…”

Section: Discussion On Outcomes On Nmr and Ms And B Vitaminsmentioning

confidence: 99%

A pilot clinical trial assessing the efficacy and safety of supplementation with a B complex vitamin to reduce the incidence of chemotherapy induced peripheral neuropathy in patients diagnosed with a malignancy

Schloss¹

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Association of Low Baseline Levels of Erythrocyte Folate With Treatment Nonresponse at Three Months in Rheumatoid Arthritis Patients Receiving Methotrexate

Rotte

Jong

Pluijm

et al. 2013

Arthritis & Rheumatism

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Objective. To investigate whether baseline concentrations of one-carbon metabolism biomarkers are associated with treatment nonresponse and adverse events in rheumatoid arthritis (RA) patients receiving methotrexate (MTX).Methods. A prospective derivation cohort (n ‫؍‬ 285) and validation cohort (n ‫؍‬ 102) of RA patients receiving MTX were studied. Concentrations of plasma homocysteine, serum vitamin B 12 , serum folate, erythrocyte vitamin B 6 , and erythrocyte folate were determined at baseline and after 3 months of treatment. Nonresponse after 3 months was assessed using the Disease Activity Score in 28 joints (DAS28) and the European League Against Rheumatism (EULAR) response criteria. Adverse events at 3 months were assessed using biochemical parameters and health status questionnaires. Analyses were corrected for baseline DAS28, age, sex, MTX dose, comedications, and presence of the methylenetetrahydrofolate reductase 677TT genotype.Results. In the derivation cohort, the mean DAS28 scores at baseline and 3 months were 4.94 and 3.12, respectively, and 78% of patients experienced adverse events. This was similar between the 2 cohorts, despite a lower MTX dose in the validation cohort. Patients with lower levels of erythrocyte folate at baseline had a higher DAS28 at 3 months in both the derivation cohort (␤ ‫؍‬ ؊0.15, P ‫؍‬ 0.037) and the validation cohort (␤ ‫؍‬ ؊0.20, P ‫؍‬ 0.048). In line with these results, lower baseline erythrocyte folate levels were linearly associated with a 3-month DAS28 of >3.2 in both cohorts (derivation cohort, P ‫؍‬ 0.049; validation cohort, P ‫؍‬ 0.021) and with nonresponse according to the EULAR criteria (derivation cohort, P ‫؍‬ 0.066; validation cohort, P ‫؍‬ 0.027). None of the other biomarkers (levels at baseline or changes over 3 months) were associated with the DAS28 or treatment nonresponse. Baseline levels of the biomarkers and changes in levels after 3 months were not associated with incidence of adverse events.Conclusion. A low baseline concentration of erythrocyte folate is associated with high disease activity and nonresponse at 3 months after the start of MTX treatment and could be used in prediction models for MTX outcome. None of the investigated one-carbon metabolism biomarkers were associated with incidence of adverse events at 3 months.

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A stable isotope dilution LC–ESI-MS/MS method for the quantification of pyridoxal-5′-phosphate in whole blood

Cited by 15 publications

References 28 publications

A novel fully validated LC–MS/MS method for quantification of pyridoxal-5′-phosphate concentrations in samples of human whole blood

A novel fully validated LC–MS/MS method for quantification of pyridoxal-5′-phosphate concentrations in samples of human whole blood

A pilot clinical trial assessing the efficacy and safety of supplementation with a B complex vitamin to reduce the incidence of chemotherapy induced peripheral neuropathy in patients diagnosed with a malignancy

Association of Low Baseline Levels of Erythrocyte Folate With Treatment Nonresponse at Three Months in Rheumatoid Arthritis Patients Receiving Methotrexate

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