Bakirdere S. | Bramanti E. | D'ulivo A. | Ataman O.Y. | Mester Z.

Article | 2010 | Analytica Chimica Acta680 ( 01.Feb ) , pp.41 - 47

An analytical method was developed for the determination of thiols in biological samples. Reverse phase chromatography coupled to ICP quaduropole MS or Orbitrap MS was employed for the separation and detection of thiols. For the determination of total thiols, oxidized thiols were reduced using dithiothreitol (DTT). Reduction efficiencies for species of interest were found to be close to 100%. Reduced thiols were derivatized by p-hydroxymercuribenzoate (PHMB) and then separated on a C8 column. Optimization of the extraction, separation and detection steps of the HPLC-ICP-MS and HPLC-Orbitrap MS methods was carried out. Detection limi . . .ts for cysteine, homocysteine, selenocysteine, glutathione, selenomethionine and cysteinyl-glycine were found to be 18, 34, 39, 12, 128 and 103fmol, respectively, using HPLC-Orbitrap MS and 730, 1110, 440, 1110 and 580fmol for cysteine, homocysteine, selenocysteine, glutathione, and cysteinyl-glycine using HPLC-ICP-MS. Contrary to expectation, the LODs and RSDs are higher for the HPLC-ICP-MS instrument, therefore HPLC-Orbitrap MS was used for the determination of thiols in yeast samples. Three different brands of baker's yeast and a selenized yeast were analyzed. The GSH and cysteine levels found in these samples ranged from 4.45 to 17.87µmolg-1 and 0.61 to 1.32µmolg-1, respectively. © 2010 Elsevier B.V Daha fazlası Daha az

Isik, Hatice | Sahbaz, Ahmet | Timur, Hakan | Aynioglu, Oner | Mert, Sule Atalay | Balik, Ahmet Rifat | Erel, Ozcan

Article | 2017 | GYNECOLOGIC AND OBSTETRIC INVESTIGATION82 ( 2 ) , pp.113 - 118

The study aimed to compare the dynamic thiol/disulfide homeostasis between patients with premature ovarian failure (POF) and healthy women. A total of 77 women, 40 POF and 37 healthy controls, were recruited from a university hospital between December 2013 and June 2015. Blood samples were taken from patients to evaluate follicle stimulating hormone (FSH), luteinizing hormone, estradiol and thiol/disulfide levels. A new, fully automated method was used to measure plasma thiol, total thiol and disulfide levels. Disulfide levels, disulfide/native thiol and disulfide/total thiol ratios were significantly increased, native thiol/total t . . .hiol levels were significantly decreased in POF patients compared to controls (p < 0.001). FSH was negatively correlated with native thiol and native thiol/total thiol levels and positively with disulfide, disulfide/native thiol, and disulfide/total thiol levels. This is the first study demonstrating the thiol/disulfide homeostasis in women with POF and may help us understanding the pathophysiology. (C) 2016 S. Karger AG, Base Daha fazlası Daha az