Home About us Contact
|
Home About us Contact | ||
|
|
||
Multiple Analytes (multiple + analyte)
Selected AbstractsMass spectrometry in newborn and metabolic screening: historical perspective and future directionsJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 2 2009Donald H. Chace Abstract The growth of mass spectrometry (MS) in clinical chemistry has primarily occurred in two areas: the traditional clinical chemistry areas of toxicology and therapeutic drug monitoring and more recent, human genetics and metabolism, specifically inherited disorders of intermediary metabolism and newborn screening. Capillary gas chromatography and electrospray tandem MS are the two most common applications used to detect metabolic disease in screening, diagnostics and disease monitoring of treated patients. A few drops of blood from several million newborn infants are screened annually throughout the world making this the largest application of MS in medicine. Understanding the technique, how it grew from a few dozen samples per week in the early 1990s to increasing daily volume today will provide important information for new tests that either expand newborn screening or screening in other areas of metabolism and endocrinology. There are numerous challenges to the further expansion of MS in clinical chemistry but also many new opportunities in closely related applications. The model of newborn screening and MS in medicine may be useful in developing other applications that go beyond newborns and inherited metabolic disease. As MS continues to expand in clinical chemistry, it is clear that two features will drive its success. These features are excellent selectivity and multiple analyte or profile analysis; features recognized in the 1950s and remain true today. Copyright © 2008 John Wiley & Sons, Ltd. [source] Liquid chromatography,tandem mass spectrometry applications in endocrinologyMASS SPECTROMETRY REVIEWS, Issue 3 2010Mark M. Kushnir Abstract Liquid chromatography,tandem mass spectrometry (LC,MS/MS) has been recognized as a primary methodology for the accurate analysis of endogenous steroid hormones in biological samples. This review focuses on the use of LC,MS/MS in clinical laboratories to assist with the diagnosis of diverse groups of endocrine and metabolic diseases. Described analytical methods use on-line and off-line sample preparation and analytical derivatization to enhance analytical sensitivity, specificity, and clinical utility. Advantages of LC,MS/MS as an analytical technique include high specificity, possibility to simultaneously measure multiple analytes, and the ability to assess the specificity of the analysis in every sample. All described analytical methods were extensively validated, utilized in routine diagnostic practice, and were applied in a number of clinical and epidemiological studies, including a study of the steroidogenesis in ovarian follicles. © 2009 Wiley Periodicals, Inc. Mass Spec Rev 29:480-502, 2010 [source] A novel on-line solid-phase extraction approach integrated with a monolithic column and tandem mass spectrometry for direct plasma analysis of multiple drugs and metabolitesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 22 2005Xu Zang An on-line solid-phase extraction liquid chromatography/tandem mass spectrometry (SPE LC/MS/MS) assay using a newly developed SPE column and a monolithic column was developed and validated for direct analysis of plasma samples containing multiple analytes. This assay was developed in an effort to increase bioanalysis throughput and reduce the complexity of on-line SPE LC/MS/MS systems. A simple column-switching configuration that requires only one six-port valve and one HPLC pumping system was employed for on-line plasma sample preparation and subsequent gradient chromatographic separation. The resulting analytical method couples the desired sensitivity with ease of use. The method was found to perform satisfactorily for direct plasma analysis with respect to assay linearity, specificity, sensitivity, precision, accuracy, carryover, and short-term stability of an eight-analyte mixture in plasma. A gradient LC condition was applied to separate the eight analytes that cannot be distinctly differentiated by MS/MS. With a run time for every injection of 2.8,min, a minimum of 300 direct plasma injections were made on one on-line SPE column without noticeable changes in system performance. Due to the ruggedness and simplicity of this system, generic methods can be easily developed and applied to analyze a wide variety of compounds in a high-throughput manner without laborious off-line sample preparation. Copyright © 2005 John Wiley & Sons, Ltd. [source] 2167: Tear film biomarkers as prognostic indicators for recurrent pterygiumACTA OPHTHALMOLOGICA, Issue 2010N ZAKARIA Purpose The aim of this project is to establish the use of IL-6, IL-8 and VEGF as biomarkers in the tear film for early detection of recurrent pterygium. Methods Cytometric Bead Array (CBA) kits will be used to perform multicytokine assays in the tear samples of eyes having pterygium before and after surgical resection of the pterygia. This technique utilizes flow cytometry to determine the concentrations of multiple analytes namely IL-6, IL-8 and VEGF (proposed biomarkers) present in small volumes of tear fluid.Patients with pterygia showing corneal encroachment and requiring surgical excision will be recruited in this study along with a second population of control subjects consisting of individuals with no history of eye diseases or contact lens wear. After instilling a local anesthetic, 3 drops of normal saline will be applied and the at least 50µl of the diluted epithelial secretions collected and stored at -80°C for CBA analysis. From the results we can determine the baseline levels of IL-6, IL-8 and VEGF present in normal epithelial secretions and correlate it with potentially higher levels in the eyes of patients with pterygia. By collecting post op epithelial secretions at different time points along with regular ocular surface photographs and grading of any recurrent pterygia we will be able to ascertain the role of these cytokines and growth factors as biomarkers for recurrent pterygia. Conclusion By establishing higher tear film levels of IL-6, IL-8 and VEGF in eyes with pterygia compared to normal eyes and the return to baseline levels post excision we can begin to ascertain the role of these key players in the pathogenesis of pterygia. [source] | ||||||||||