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1.
Anal Chim Acta ; 707(1-2): 197-203, 2011 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-22027139

RESUMEN

A fully automated, non invasive, rapid and high-throughput method for the direct determination of sarcosine and N-ethylglycine in urine and urinary sediments using hexyl chloroformate derivatization followed by direct immersion solid-phase micro extraction and fast gas chromatography-mass spectrometric analysis was developed and validated. The use of a new ionic liquid narrow bore column, as well as the automation and miniaturization of the preparation procedure by a customized configuration of the utilized XYZ robotic system, allowed a friendly use of the GC apparatus achieving a quantitation limit of 0.06 µg L(-1) for sarcosine, good repeatability with CV always lower than 7% and reduced analysis times useful for point-of-care testing. The method was then applied for the analysis of 56 samples of urine and urinary sediments in healthy subjects, in those with benign prostatic hypertrophy and in patients with clinically localized prostate cancer. The results obtained showed that the medians of sarcosine/creatinine in urine were 103, 137 and 267 µg g(-1) respectively, thus assessing the potential use of sarcosine as urinary biomarker for prostate cancer detection. The highest values of sensitivity (79%) and specificity (87%) were obtained in correspondence of a cut-off value of 179 µg sarcosine(g creatinine)(-1), thus by using this cut-off threshold, sarcosine was significantly associated with the presence of cancer (p<0.0001). Finally, ROC analyses proved that the discrimination between clinically localized prostate cancer and patients without evidence of tumor is significantly correlated with sarcosine.


Asunto(s)
Cromatografía de Gases y Espectrometría de Masas/métodos , Líquidos Iónicos/análisis , Glicinas N-Sustituídas/orina , Sarcosina/orina , Microextracción en Fase Sólida/métodos , Humanos , Líquidos Iónicos/química , Masculino , Factores de Tiempo
2.
Anal Sci ; 24(12): 1629-31, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19075476

RESUMEN

A simple and highly sensitive HPLC for the determination of N-ethylglycine in urine was developed. The labeling reaction of N-ethylglycine with 4-(5,6-dimethoxy-2-phthalimidinyl)-2-methoxyphenylsulfonyl chloride was carried out at 70 degrees C for 15 min at pH 9.0. The fluorescent derivative was separated on a reversed-phase column and detected at excitation and emission wavelengths of 320 and 400 nm, respectively. The detection limit of N-ethylglycine was 15 fmol (S/N = 3). The recovery of N-ethylglycine added to urine was 101.9%. The concentration of N-ethylglycine in urine of cancer patients with metastatic bone disease was 11.3 +/- 22.0 nmol/mg creatinine, and that of normal subject was 0.4 +/- 0.4 nmol/mg creatinine.


Asunto(s)
Neoplasias Óseas/secundario , Neoplasias Óseas/orina , Colorantes Fluorescentes/química , Glicinas N-Sustituídas/orina , Ftalimidas/química , Adulto , Estudios de Casos y Controles , Cromatografía Líquida de Alta Presión , Humanos , Concentración de Iones de Hidrógeno , Persona de Mediana Edad , Glicinas N-Sustituídas/química , Sensibilidad y Especificidad , Espectrometría de Fluorescencia , Adulto Joven , o-Ftalaldehído/química
3.
Clin Chim Acta ; 376(1-2): 226-8, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16962088

RESUMEN

BACKGROUND: Previously, a HPLC method for the determination of N-terminal prolyl dipeptides, proline and hydroxyproline in urine with fluorescence detection after pre-column derivatization with 4-(5,6-dimethoxy-2-phthalimidinyl)-2-methoxyphenylsulfonyl chloride (DMS-Cl) [Inoue H, Iguchi H, Kono A, Tsuruta Y. Highly sensitive determination of N-terminal prolyl dipeptides, proline and hydroxyproline in urine by high-performance liquid chromatography using a new fluorescent labelling reagent, 4-(5,6-dimethoxy-2-phthalimidinyl)-2-methoxyphenylsulfonyl chloride. J Chromatogr 1999;724:221-230] was developed to study the relation between those analytes and bone diseases. When the urinary analytes were measured, a large peak due to an unknown substance was recognized in the chromatograms of cancer patients with metastatic bone disease, although it was scarcely present in normal subjects. In this study, we identified the unknown substance. METHODS: The fluorescent fraction based on the unknown substance was collected using HPLC and the structure of the fluorescence product was analyzed with MS, (1)H NMR and (13)C NMR. RESULTS: The fluorescence product based on the unknown substance was established to be a DMS-derivative of N-ethylglycine. CONCLUSIONS: Excretion of N-ethylglycine in the urine of cancer patients with metastatic bone disease is recognized, although N-ethylglycine is scarcely excreted in the urine of normal subjects.


Asunto(s)
Neoplasias Óseas/química , Neoplasias Óseas/diagnóstico , Glicinas N-Sustituídas/orina , Neoplasias Óseas/secundario , Estructura Molecular , Glicinas N-Sustituídas/química , Espectrometría de Fluorescencia
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