Application of the Phenomenex EZ:faast™ amino acid analysis kit for rapid gas-chromatographic determination of concentrations of plasma tryptophan and its brain uptake competitors

Badawy, Abdulla A.-B.; Morgan, Chris; Turner, Jon

doi:10.1007/s00726-007-0012-7

Cited by 96 publications

(73 citation statements)

References 12 publications

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“…Plasma adiponectin and leptin concentrations were determined by performing ELISA and a radioimmunoassay, respectively (both from EMD Millipore). Plasma samples for BCAAs were prepared according to the manufacturer's instructions (Phenomenex) for analyses by gas chromatography-mass spectrometry (41). The glucose, palmitate, and leucine TTR in plasma and the leucine TTR in VLDL particles were determined by using gas chromatography-mass spectrometry (3,4).…”

Section: Methodsmentioning

confidence: 99%

Metabolically normal obese people are protected from adverse effects following weight gain

Fabbrini¹,

Yoshino²,

Yoshino³

et al. 2015

J. Clin. Invest.

147

150

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BACKGROUND.Obesity is associated with insulin resistance and increased intrahepatic triglyceride (IHTG) content, both of which are key risk factors for diabetes and cardiovascular disease. However, a subset of obese people does not develop these metabolic complications. Here, we tested the hypothesis that people defined by IHTG content and insulin sensitivity as "metabolically normal obese" (MNO), but not those defined as "metabolically abnormal obese" (MAO), are protected from the adverse metabolic effects of weight gain. METHODS.Body composition, multiorgan insulin sensitivity, VLDL apolipoprotein B100 (apoB100) kinetics, and global transcriptional profile in adipose tissue were evaluated before and after moderate (~6%) weight gain in MNO (n = 12) and MAO (n = 8) subjects with a mean BMI of 36 ± 4 kg/m 2 who were matched for BMI and fat mass. RESULTS.Although the increase in body weight and fat mass was the same in both groups, hepatic, skeletal muscle, and adipose tissue insulin sensitivity deteriorated, and VLDL apoB100 concentrations and secretion rates increased in MAO, but not MNO, subjects. Moreover, biological pathways and genes associated with adipose tissue lipogenesis increased in MNO, but not MAO, subjects.CONCLUSIONS. These data demonstrate that MNO people are resistant, whereas MAO people are predisposed, to the adverse metabolic effects of moderate weight gain and that increased adipose tissue capacity for lipogenesis might help protect MNO people from weight gain-induced metabolic dysfunction.TRIAL REGISTRATION. ClinicalTrials.gov NCT01184170.

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Section: Methodsmentioning

confidence: 99%

Metabolically normal obese people are protected from adverse effects following weight gain

Fabbrini¹,

Yoshino²,

Yoshino³

et al. 2015

J. Clin. Invest.

147

150

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“…Interest in sarcosine as a marker molecule remains topical, as shown by a recent modification of sarcosine assay by GC/MS in urine. 8 We present measurements in plasma of prostate cancer patients characterised by PSA, tumour stage and Gleason score using GC/MS for sarcosine methodology 9,10 to elaborate further on the suitability of sarcosine as a marker for prostate cancer.…”

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confidence: 99%

Plasma sarcosine does not distinguish early and advanced stages of prostate cancer

et al. 2012

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The identification of prostate cancer remains problematic; no single, simple procedure exists for a reliable diagnosis. Prostate specific antigen (PSA), while non-invasive and easily measurable in serum, is not specific owing to false-positives from benign prostatic hyperplasia (BPH), inflammatory conditions and prostatic trauma. Additional diagnostic information must therefore be obtained by transrectal ultrasonography (TRUS) and digital rectal examination (DRE) to assess prostate size and morphology. Final confirmation of a malignancy requires histopathological analysis of several biopsies. A remaining hurdle in the identification process is the existence of indolent organ-confined disease and aggressive metastatic prostate cancer that can only be distinguished by additional imaging or nuclear medicine procedures.In a new approach to this diagnostic dilemma, it has been argued that screening for changes in metabolite expression resulting from gene silencing and gene activation could be used to identify a specific biological marker that increases in the transformation process. Therefore, a paper elaborating on metabolite expression in clinical samples of benign, localised and metastatic prostate cancer 1 was enthusiastically received and debated in editorials. [2][3][4][5] The proposal that sarcosine (N-methylglycine) (a metabolite of choline found in urine) may be characteristic for prostate cancer progression has since been examined in other laboratories. 1 These investigations found sarcosine levels in urine 6 and serum 7 to be constant, irrespective of sample pathology. From our own and published preliminary measurements, it is nevertheless clear that sarcosine-alanine ratios in prostate tumour patients are often elevated above controls and are spread over a wider range. 1,7,17 A relationship between sarcosine and disease therefore cannot as yet be totally ruled out. Interest in sarcosine as a marker molecule remains topical, as shown by a recent modification of sarcosine assay by GC/MS in urine. 8 We present measurements in plasma of prostate cancer patients characterised by PSA, tumour stage and Gleason score using GC/MS for sarcosine methodology 9,10 to elaborate further on the suitability of sarcosine as a marker for prostate cancer. MethodsPatient blood was collected by venipuncture and centrifuged, and clear supernatants were stored at -20°C. The AxSYM total PSA was determined by a MEIA microparticle enzyme immune assay (Abbott) and expressed as ng/ml. Ethical approval was granted by the University of Stellenbosch Health Research Ethics Committee (N09/11/330).Sarcosine and alanine were quantified in plasma by gaschromatograph mass spectrometry. Briefly, amino acids were extracted from 100 µl of acidified plasma by solid phase extraction onto a cation exchange column before being washed, eluted and derivatised to their corresponding alkyl chloroformates using a commercial kit (EZ:faast, Phenomenex, Torrance CA, USA). After derivatisation, the amino acids were extracted into solvent and 2 µl injected in...

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“…It was successfully used by Fonteh et al 12 to quantify free AA and dipeptides in human samples with their final determination on LC-MS/MS with the total run time of 35,5 min. and also by many other scientists to determine AA in biological fluids 9,[13][14][15] . However, there are no reports to date on the application of EZ:faast (TM) and LC-MS/MS for the analysis of AA in plants.…”

Section: Introductionmentioning

confidence: 99%

Determination of free amino acids in plants by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS)

et al. 2015

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The manuscript " Determination of free amino acids in plants by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS)" describes the analysis of 19 proteinogenic amino acids by UHPLC-MS/MS using the EZ:faast™ LC-MS Free Amino Acid kit commercially available from Phenomenex. Optimization of the MS as well as MS/MS parameters for confirmation and quantification transitions of each amino acid is presented. Validation of the method including the extraction step was performed with standard solutions and spiked weed plant samples with regard to the linear range, linearity, LODs, LOQs and intra/inter-day precision. Recoveries had been determined by weed samples spiked with amino acid internal standards from the EZ:faast™ LC-MS Free Amino Acid kit. The validated method has been applied to the analysis of Stellaria media weed samples.Application of the EZ:faast™ LC-MS Free Amino Acid kit has been published by several other authors, however the novelty of this paper is its first application to plant samples after the comprehensive validation of the method in order to achieve accurate analysis of free amino acids. Our aim was to validate the method according to strict guidelines -ICH Q2 (R1) and also European SANCO, due to specific criteria concerning LC-MS/MS technique parameters in order to demonstrate that this analytical procedure is suitable for its intended purpose in plant matrices. As the EZ:faast™ kit is known and used widely among scientists, we think that complete validation for all proteinogenic amino acids in plants would be desirable, as we were not able not find any manuscript dealing with these issues, therefore societal impact is justified. Furthermore, many papers were published utilizing this kit, but most of them analyse only few amino acids. They neither present the MS/MS optimization parameters for all amino acids nor validation procedure, so the reliability of those methods is doubtful. Extraction using water when plants amino acids remain in native state is a merit for many scientists dealing with plant stress, when they are interested in non-altered plant composition in order to check how plants react after physiological stress. Moreover, not all amino acids are soluble in organic solvents or their solubility is hindered. As far as we are concerned there has not been any article incorporating water and the EZ:faast™ kit to study free amino acids so we feel it is worth and significant to fill this niche. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 ABSTRACT A robust and sensitive method for identification (quantification and confirmation) of 19 free amino acids in plant matrice -Stellaria media, based on liquid chromatographyelectrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS), with a triple quadrupole analyser, has been developed. Regarding MS optimization, the flow injection analysis (FIA)...

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Application of the Phenomenex EZ:faast™ amino acid analysis kit for rapid gas-chromatographic determination of concentrations of plasma tryptophan and its brain uptake competitors

Cited by 96 publications

References 12 publications

Metabolically normal obese people are protected from adverse effects following weight gain

Metabolically normal obese people are protected from adverse effects following weight gain

Plasma sarcosine does not distinguish early and advanced stages of prostate cancer

Determination of free amino acids in plants by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS)

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