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Agilent Technologies (agilent + technology)
Selected AbstractsReactive oxygen species induce RNA damage in human atherosclerosisEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 5 2004W. Martinet Abstract Background, Reactive oxygen species (ROS)-induced DNA damage has recently been identified in both human and experimental atherosclerosis. This study was undertaken to investigate whether RNA damage occurs in human atherosclerotic plaques and whether this could be related to oxidative stress. Materials and methods, The integrity of total RNA isolated from carotid endarterectomy specimens (n = 20) and nonatherosclerotic mammary arteries (n = 20) was analyzed using an Agilent 2100 Bioanalyser (Agilent Technologies, Palo Alto, CA). Oxidative modifications of RNA were detected by immunohistochemistry. Results, Eleven out of 20 atherosclerotic plaques showed a significant reduction of the 18S/28S rRNA peaks and a shift in the RNA electropherogram to shorter fragment sizes. In contrast, all mammary arteries showed good-quality RNA with clear 18S and 28S rRNA peaks. Strong nuclear and cytoplasmic immunoreactivity for oxidative damage marker 7,8-dihydro-8-oxo-2,-guanosine (8-oxoG) could be detected in the entire plaque in smooth muscle cells (SMCs), macrophages and endothelial cells, but not in SMCs of adjacent normal media or in mammary arteries. Cytoplasmic 8-oxoG staining in the plaque clearly diminished when tissue sections were pretreated with RNase A, suggesting oxidative base damage of RNA. In vitro treatment of total RNA with ROS-releasing compounds induced RNA degradation. Conclusion, Both loss of RNA integrity and 8-oxoG oxidative modifications were found in human atherosclerotic plaques. Because RNA damage may affect in vitro transcript quantification, RT-PCR results must be interpreted cautiously if independent experimental validation (e.g. evaluation of RNA integrity) is lacking. [source] A microarray's view of life in the desert: adding a powerful evolutionary genomics tool to the packrat's middenMOLECULAR ECOLOGY, Issue 11 2009MARJORIE D MATOCQ Identifying the genetic architecture of adaptive traits is fundamental to understanding how organisms respond to their environment, over both ecological and evolutionary timeframes. Microarray technology that allows us to capture the simultaneous expression of thousands of genes provides unparalleled insight into how organisms cope with their environment at the transcriptional level. Recent studies in Molecular Ecology demonstrate how microarrays can rapidly identify which genes and pathways allow organisms to face some of the most fundamental physiological challenges posed by the environment, including compensation for the hypoxic and thermal stress of high-altitudes (Cheviron et al. 2008) and, in this issue, the biotransformation of toxic plant secondary compounds by mammals (Magnanou et al. 2009). Microarrays (Ekins et al. 1989; Fodor et al. 1991) are glass slides affixed with hundreds to thousands of oligonucleotide or cDNA sequences (probes). Messenger RNA transcripts (typically reverse transcribed to cDNA) are isolated from a tissue/sample of interest and hybridized to the array. Binding to specific probes indicates that a particular gene was transcriptionally active at or near the time of sampling and thus provides a potentially comprehensive measure of gene expression. Although a tremendously powerful tool, commercially produced oligonucleotide arrays are only available for a handful of model organisms. Nonetheless, evolutionary ecologists have exploited this resource by using a cross-species hybridization approach (e.g. Saetre et al. 2004), that is, hybridizing a model organism array with a nonmodel sample (Bar-Or et al. 2007). Magnanou et al. (2009) present a novel example of using a model muroid microarray (Agilent Technologies, Rattus) to study physiological response in a wild, nonmodel muroid, Neotoma. [source] 5-in-1 biodiesel: an approach to combining five biodiesel gas chromatographic methods on a single instrumentBIOFUELS, BIOPRODUCTS AND BIOREFINING, Issue 3 2009James D. McCurry James D. McCurry and Wesley Norman report on a new technology developed at Agilent Technologies. A small external, isothermal, capillary-column oven is used to isolate a polar wax column from a high-temperature column on a single gas chromatograph (GC). This allows five different biodiesel methods to reside on the same GC which would otherwise require two separate instruments. The isothermal biodiesel methods are used to test the external column oven performance and demonstrate the ability to combine these methods on a single GC. © 2009 Society of Chemical Industry and John Wiley & Sons, Ltd [source] Liquid chromatographic/mass spectrometric assay of rabprazole in dog plasma for a pharmacokinetic studyBIOMEDICAL CHROMATOGRAPHY, Issue 11 2006Shao Feng Abstract In order to evaluate the pharmacokinetic (PK) profile of rabeprazole (RA) sterile powder for injection, a rapid, sensitive and specific assay for quantitative determination of RA in dog plasma was developed and validated. After a liquid,liquid extraction procedure, samples were analyzed by liquid chromatography,electrospray ionization mass spectrometry (LC-ESI-MS) using omepazole as the internal standard (IS). The analyte and IS was chromatographed on a ZORBAX Extend-C18 analytical column (50 × 2 mm i.d, 5 µm, Agilent Technologies, USA). The assay was linear in the range 1,2000 ng/mL. The lower limit of quantification of RA was 1 ng/mL. The recovery of RA was greater than 70%. The within- and between-batch accuracy was 102.7,107.4% and 103.5,105.7%, respectively. The plasma samples for the PK study were collected at defined time points during and after an intravenous injection (1 mg/kg) to beagle dogs and analyzed by LC-ESI-MS method. The PK parameters, such as half-life, volume of distribution, total clearance and elimination rate constant, were determined. The PK profile of RA gave insights into the application in the clinics. Copyright © 2006 John Wiley & Sons, Ltd. [source] | ||||||||||