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pH-Dependent Selective Colorimetric Detection of Proline and Hydroxyproline with Meldrum’s Acid-Furfural Conjugate. CHEMOSENSORS 2021. [DOI: 10.3390/chemosensors9120343] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Activated 2-furfural gives intense color formation when reacted with amines, due to a ring opening reaction cascade that furnishes a conjugated molecular system. Unique colorimetric characteristic of this reaction makes it an interesting candidate for developing chemosensors operating in visible range. Among many activated 2-furfural derivatives, Meldrum’s acid furfural conjugate (MAFC) recently gained significant interest as colorimetric chemosensor. MAFC has been explored as selective chemosensor for detecting amines in solution, secondary amines on polymer surfaces and even nitrogen rich amino acids (AA) in aqueous solution. In this work, the pH dependency of MAFC-AA reaction is explored. It was found that proline gives an exceptionally fast colored reaction at pH 11, whereas at other pHs, no naked eye color product formation was observed. The reaction sequence including ring opening reaction upon nucleophilic addition of cyclic amine of proline resulting in a conjugated triene was confirmed by NMR titrations. The highly pH dependent reaction can e.g., potentially be used to detect proline presence in biological samples. An even more intense color formation takes place in the reaction of natural proline derivative 4-hydroxyproline. The detection limit of proline and 4-hydroxyproline with MAFC solution was found to be 11 µM and 6 µM respectively.
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Brito A, Grapov D, Fahrmann J, Harvey D, Green R, Miller JW, Fedosov SN, Shahab-Ferdows S, Hampel D, Pedersen TL, Fiehn O, Newman JW, Uauy R, Allen LH. The Human Serum Metabolome of Vitamin B-12 Deficiency and Repletion, and Associations with Neurological Function in Elderly Adults. J Nutr 2017; 147:1839-1849. [PMID: 28794205 PMCID: PMC5610547 DOI: 10.3945/jn.117.248278] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 02/21/2017] [Accepted: 06/21/2017] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND The specific metabolomic perturbations that occur in vitamin B-12 deficiency, and their associations with neurological function, are not well characterized. OBJECTIVE We sought to characterize the human serum metabolome in subclinical vitamin B-12 deficiency and repletion. METHODS A before-and-after treatment study provided 1 injection of 10 mg vitamin B-12 (with 100 mg pyridoxine and 100 mg thiamin) to 27 community-dwelling elderly Chileans (∼74 y old) with vitamin B-12 deficiency, as evaluated with serum vitamin B-12, total plasma homocysteine (tHcy), methylmalonic acid (MMA), and holotranscobalamin. The combined indicator of vitamin B-12 status (cB-12) was computed. Targeted metabolites [166 acylcarnitines, amino acids, sugars, glycerophospholipids, and sphingolipids (liquid chromatography-tandem mass spectrometry)], and untargeted metabolites [247 chemical entities (gas chromatography time-of-flight mass spectrometry)] were measured at baseline and 4 mo after treatment. A peripheral nerve score was developed. Differences before and after treatment were examined. For targeted metabolomics, the data from 18 individuals with adequate vitamin B-12 status (selected from the same population) were added to the before-and-after treatment data set. Network visualizations and metabolic pathways are illustrated. RESULTS The injection increased serum vitamin B-12, holotranscobalamin, and cB-12 (P < 0.001), and reduced tHcy and serum MMA (P < 0.001). Metabolomic changes from before to after treatment included increases (P < 0.001) in acylcarnitines, plasmalogens, and other phospholipids, whereas proline and other intermediaries of one-carbon metabolism-that is, methionine and cysteine-were reduced (P < 0.001). Direct significant correlations (P < 0.05 after the false discovery rate procedure) were identified between acylcarnitines, plasmalogens, phospholipids, lyso-phospholipids, and sphingomyelins compared with vitamin B-12 status and nerve function. Multiple connections were identified with primary metabolites (e.g., an inverse relation between vitamin B-12 markers and tryptophan, tyrosine, and pyruvic, succinic, and citric acids, and a direct correlation between the nerve score and arginine). CONCLUSIONS The human serum metabolome in vitamin B-12 deficiency and the changes that occur after supplementation are characterized. Metabolomics revealed connections between vitamin B-12 status and serum metabolic markers of mitochondrial function, myelin integrity, oxidative stress, and peripheral nerve function, including some previously implicated in Alzheimer and Parkinson diseases. This trial was registered at www.controlled-trials.com as ISRCTN02694183.
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Affiliation(s)
- Alex Brito
- USDA Agricultural Research Service, Western Human Nutrition Research Center, Davis, CA
| | - Dmitry Grapov
- NIH West Coast Metabolomics Center, University of California, Davis, Davis, CA
| | - Johannes Fahrmann
- NIH West Coast Metabolomics Center, University of California, Davis, Davis, CA
| | - Danielle Harvey
- Department of Public Health Sciences, School of Medicine, University of California, Davis, Davis, CA
| | - Ralph Green
- Department of Pathology and Laboratory Medicine, University of California, Davis, Davis, CA
| | - Joshua W Miller
- Department of Pathology and Laboratory Medicine, University of California, Davis, Davis, CA
- Department of Nutrition, University of California, Davis, Davis, CA
| | - Sergey N Fedosov
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | | | - Daniela Hampel
- USDA Agricultural Research Service, Western Human Nutrition Research Center, Davis, CA
- Department of Nutrition, University of California, Davis, Davis, CA
| | - Theresa L Pedersen
- USDA Agricultural Research Service, Western Human Nutrition Research Center, Davis, CA
| | - Oliver Fiehn
- NIH West Coast Metabolomics Center, University of California, Davis, Davis, CA
| | - John W Newman
- USDA Agricultural Research Service, Western Human Nutrition Research Center, Davis, CA
- NIH West Coast Metabolomics Center, University of California, Davis, Davis, CA
- Department of Nutrition, University of California, Davis, Davis, CA
| | - Ricardo Uauy
- Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile
| | - Lindsay H Allen
- USDA Agricultural Research Service, Western Human Nutrition Research Center, Davis, CA
- Department of Nutrition, University of California, Davis, Davis, CA
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Congress Report: 5th Central and Eastern Europe (CEE) Summit on Osteoporosis in Bratislava, 2-3 December 2011. Arch Osteoporos 2013; 8:123. [PMID: 23400563 DOI: 10.1007/s11657-013-0123-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 11/29/2012] [Indexed: 02/03/2023]
Abstract
Major aims of the 5th Central and Eastern Europe (CEE) Summit on Osteoporosis held in Bratislava, Slovakia, on 2 and 3 December 2011, were to provide participants with state-of-the-art knowledge in the fields of osteoporosis research, diagnosis, and therapy and to evaluate, compare, and discuss the very heterogeneous health care situations and related challenges in the different countries in CEE and elsewhere. The summit was attended by 70 delegates from 15 countries. State-of-the-art lectures given by international authorities on osteoporosis covered a broad spectrum of topics ranging from osteoporosis in the male population, novel therapies in osteoporosis such as cathepsin K and sclerostin inhibitors, and the implementation and use of FRAX® in CEE, to an update on denosumab for the management of osteoporosis. Workshops organized to enable the exchange of individual experiences addressed the importance and current availability of osteology training for physicians and the impact of patient training programs on therapy compliance. Furthermore, the availability of and need for standardized quality controls and therapy guidelines in different CEE countries were discussed. Finally, based on a questionnaire, a very up-to-date analysis of all participating countries regarding incidences of osteoporosis, commonly used diagnostic and therapeutic measures, the number of specialists and specialized hospitals, and differences in the reimbursement situation in the different countries was generated and presented. On the whole, the very authentic contributions and the synergistic exchange of ideas allowed the identification of both positive developments as well as still existing issues and needs in diagnosis and therapy of osteoporosis.
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Cimlová J, Kružberská P, Švagera Z, Hušek P, Šimek P. In situ derivatization-liquid liquid extraction as a sample preparation strategy for the determination of urinary biomarker prolyl-4-hydroxyproline by liquid chromatography-tandem mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2012; 47:294-302. [PMID: 22431455 DOI: 10.1002/jms.2952] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Polar analytes that possess protic functional groups have often been treated with alkyl chloroformates to decrease their polarity and increase their volatility prior to gas chromatography-mass spectrometry analysis. This derivatization reaction has two distinct advantages. It proceeds smoothly in aqueous media, and the desired reaction products are efficiently separated from interfering ionic components by their extraction into a water-immiscible organic phase. In the present work, the derivatization-liquid liquid sample preparation was examined in detail for analysis of a potential urinary dipeptide biomarker L-prolyl-4-L-hydroxyproline (PHP) by downstream liquid chromatography coupled to electrospray mass spectrometry. PHP was treated with a series of alkyl and fluoroalkyl chloroformates in aqueous media, and the detected reaction products were investigated. Smooth conversion of PHP into the N-isobutyloxycarbonyl isobutyl ester was accomplished by the coupled action of isobutanol, isobutyl chloroformate and the pyridine catalyst. This derivative afforded a highest detector response from all the derivatized forms examined, including the nonderivatized PHP. A simple isocratic elution on a common RP-C18 HPLC column coupled with tandem mass spectrometry, and use of the synthesized heptadeuterated analog (D7-PHP) as an internal standard, enabled validation of the method and determination of PHP in human urine in less than 5 min. The in situ derivatization-liquid liquid extraction has thus been demonstrated to be a useful sample preparation strategy for the analysis of polar metabolites by liquid chromatography-tandem mass spectrometry in the complex urine matrix.
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Affiliation(s)
- Jana Cimlová
- Laboratory of Analytical Biochemistry, Biology Centre, Academy of Sciences of the Czech Republic, v.v.i. Branišovská 31, CZ-370 05, České Budějovice, Czech Republic
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Husek P, Svagera Z, Vsianský F, Franeková J, Simek P. Prolyl-hydroxyproline dipeptide in non-hydrolyzed morning urine and its value in postmenopausal osteoporosis. Clin Chem Lab Med 2008; 46:1391-7. [PMID: 18844493 DOI: 10.1515/cclm.2008.259] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Owing to the high correlation between the level of prolyl-4-hydroxyproline dipeptide in non-hydrolyzed urine and that of 4-hydroxyproline in hydrolyzed urine, we examined whether the dipeptide might function as a valuable marker of bone turnover. METHODS Based on densitometric measurements, 68 postmenopausal women were divided into groups of non-osteopathic, osteopenic and osteoporotic subjects. The dipeptide and current urinary resorption markers were assayed in morning urine, the former using liquid chromatography, the others plus serum formation markers by means of immunoassay procedures. Together with the assay of basal levels, diet-related changes and healing effect of yearly alendronate therapy were assessed. RESULTS Concentration levels in controls and osteoporotic subjects differed significantly; receiver operating characteristics yielded sensitivity of 0.743, specificity of 0.908, area under curve of 0.903, and cut-off of 10.2 micromol/mmol of creatinine. Spearman rank correlation showed the highest pair coefficient between the dipeptide and osteocalcin. Diet-related changes were not found. Following therapy, a significant decline occurred already within a trimester, whilst with the other resorption markers not until 6 months. CONCLUSIONS The ease of the dipeptide assay in non-hydrolyzed urine surpasses that of hydroxyproline, and the results present the compound as a real competition to other commonly assessed markers in osteopathies.
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Affiliation(s)
- Petr Husek
- Institute of Clinical Biochemistry, Faculty Hospital Ostrava, Ostrava, Czech Republic.
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