simultaneous method
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Uric acid and its oxidation product allantoin are excellent biomarkers of oxidative stress in humans. Currently, there are high requirements not only for tests monitoring oxidative stress but also for screening laboratory tests in general. The highest demand is imposed on the simplest sampling, easy transport of the sample, and the shortest possible analysis time. The possible solution how to fulfil the requirements is sampling by dried blood spot technique with subsequent HPLC-MS/MS analysis. A fast, sensitive, and reliable HPLC-MS/MS method for the simultaneous determination of uric acid and allantoin from dried blood spots using stable isotopically labelled analogs as internal standards was developed. The separation took place in the reversed phase within 3 min, with protein precipitation and extraction in a one-step procedure. The analytical parameters of the method were satisfactory with an excellent linear range. The presented method was used to determine allantoin and uric acid levels in dried blood spot samples from 100 healthy volunteer donors. The median uric acid concentration in the cohort was 239.3 μmol/L and the median allantoin concentration was 5.6 μmol/L. The presented analytical protocol and method are suitable for screening and monitoring allantoin and uric acid levels as biomarkers of oxidative stress in clinical practice.
... SUPPLEMENT 2 | APRIL 2014 | www.laryngoscope.com -- TRIOLOGICAL SOCIETY CANDIDATE THESIS -- DIRECT SIMULTANEOUS ... ... Significant Negative -- Gage Pressures Produced by the Flow Separation Vortices -- S5 MATERIALS AND METHODS ...
The laryngoscope, ISSN 0023-852X Volume 124, supplementum 2, April 2014
13 stran : ilustrace, tabulky ; 28 cm
- MeSH
- biomechanika MeSH
- fonace MeSH
- fonetika MeSH
- glottis MeSH
- hlas MeSH
- larynx MeSH
- měření tvorby řeči MeSH
- modely u zvířat MeSH
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- otorinolaryngologie
- lingvistika, lékařská terminologie
- NLK Publikační typ
- studie
A development of robust and rapid method with simple sample preparation for the analysis of steroids of C18-, C19-, C21- families is of interest of many research groups. Here we present a novel LC-MS/MS method for the simultaneous quantification of 32 steroid hormones in human plasma. Twenty-two of them were analyzed directly without the need for derivatization, while ten were derivatized with 2-fluoro-1-methylpyridinium p-toluenesulfonate. The steroids were separated on a C18 column with a gradient elution consisting of methanol and water with the addition of 0.1% formic acid. The mass spectrometer was operated in positive ESI mode. Validation demonstrated that the method was applicable for the quantitative analysis of two C18- steroids (estrone, estradiol), nineteen C19- steroids (testosterone, epitestosterone, dihydrotestosterone, 11-ketodihydrotestosterone, 11β-hydroxyandrostenedione, 11β-hydroxytestosterone, 11-ketotestosterone, dehydroepiandrosterone, 7α-hydroxydehydroepiandrosterone, 7β-hydroxydehydroepiandrosterone, 7-ketodehydroepiandrosterone, androsterone, epiandrosterone, androstenedione, androstenediol, 5α-androstane-3α,17β-diol, 5α-androstane-3β,17β-diol, 5β-androstane-3α,17β-diol, 5β-androstane-3β,17β-diol), and eleven C21- steroids (cortisol, 21-deoxycortisol, 11-deoxycortisol, cortisone, corticosterone, 11-deoxycorticosterone, pregnenolone, 17-hydroxypregnenolone, progesterone, 17-hydroxyprogesterone, 5α-dihydroprogesterone). The lower limits of quantification are appropriate for analyses in both physiological and various pathophysiological conditions. The accuracy, intra- and inter-day precision values as well as stability tests were in accordance with FDA Guidelines. The method will be a useful tool in investigating the mechanisms of steroid-related diseases and will serve as a steppingstone for the development of other methods for steroid analyses in various biological matrices such as prostate tissue, cerebrospinal fluid, urine, seminal fluid, and saliva.
- MeSH
- androgeny MeSH
- androstendion * MeSH
- chromatografie kapalinová metody MeSH
- estron MeSH
- lidé MeSH
- tandemová hmotnostní spektrometrie * metody MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
A simple and rapid HPLC method requiring small volumes (250 microL) of human serum after C18 SPE sample preparation was developed using monolithic technology for simultaneous determination of all-trans-retinoic acid, 13-cis-retinoic acid, retinol, gamma- and alpha-tocopherol. The monolithic column, Chromolith Performance RP-18e (100x4.6 mm), was operated at ambient temperature. The mobile phase consisted of a mixture of acetonitrile (ACN) and 1% ammonium acetate in water (AMC) at pH 7.0. The mobile phase started at 98:2 (v/v) ACN/AMC (column pre-treatment) at a flow rate of 2 mL/min, then changed to 95:5 (v/v) ACN/AMC for 4 min at a flow rate of 1.5 mL/min and a further 3 min at a flow rate of 3.2 mL/min. Detection and identification were performed using a photodiode array detector. Retinol, 13-cis- and all-trans-retinoic acid were monitored at 325 nm. Both alpha- and gamma-tocopherol were detected at 295 nm. The total analysis time was 7.2 min. Tocol (synthesized tocopherol, not occurring in humans) was used as internal standard. The method was linear in the range of 0.125-10.00 micromol/L for all-trans-retinoic acid, 0.125-5.00 micromol/L for 13-cis-retinoic acid, 0.25-10.00 micromol/L for retinol, 0.5-50.00 micromol/L for gamma-tocopherol, and 0.5-50.00 micromol/L for alpha-tocopherol. The present method may be useful for monitoring of retinoids and tocopherols in clinical studies.
- MeSH
- lidé MeSH
- molekulární struktura MeSH
- nádory krev terapie MeSH
- reprodukovatelnost výsledků MeSH
- retinoidy chemie krev MeSH
- senzitivita a specificita MeSH
- tokoferoly chemie krev MeSH
- vysokoúčinná kapalinová chromatografie metody přístrojové vybavení MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
We present a new method of multiple immunolabeling that is suitable for a broad spectrum of biomedical applications. The general concept is to label both sides of the ultrathin section with the thickness of 70-80 nm with different antibodies conjugated to gold nanoparticles and to distinguish the labeled side by advanced imaging methods with high resolution scanning electron microscopy, such as by correlating images acquired at different energies of primary electrons using different signals. From the Clinical Editor: The use of transmission electron microscopy has become an indispensible tool in the detection of cellular proteins. In this short but interesting article, the authors described their new method of labeling and the identification of four different proteins simultaneously, which represents another advance in imaging technique.
- MeSH
- akrylové pryskyřice chemie MeSH
- barvení a značení metody MeSH
- imunohistochemie MeSH
- kovové nanočástice chemie ultrastruktura MeSH
- mikrotomie metody MeSH
- reprodukovatelnost výsledků MeSH
- senzitivita a specificita MeSH
- skenovací elektrochemická mikroskopie metody MeSH
- vylepšení obrazu metody MeSH
- zlato chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
