Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.2 (focal adhesion kinase)
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Voltammetric methods are very suitable, versatile and rapid techniques for simultaneous determination of metals in complex matrices. The present work, determination of Cu(II), Sn(II), Sb(III), Tl(I), and Pb(II) by square-wave anodic-stripping voltammetry and Cr(VI) by square-wave adsorptive-stripping voltammetry, is an interesting example of the possibility of simultaneous determination of each single element in food and environmental samples, even in the presence of reciprocal interference. Dibasic ammonium citrate, pH 6.3 or 8.2, was employed as supporting electrolyte. The voltammetric measurements were carried out using a stationary hanging mercury drop electrode as working electrode and a platinum electrode and an Ag|AgCl|KCl(sat) electrode as auxiliary and reference electrodes, respectively. The analytical procedure was verified by analysis of standard reference materials--wholemeal BCR-CRM 189, wheat flour NIST-SRM 1567a, rice flour NIST-SRM 1568a, estuarine sediment BCR-CRM 277, river sediment BCR-CRM 320, and Montana soil with moderately elevated traces NIST-SRM 2711. Precision and accuracy, expressed as relative standard deviation and relative error, respectively, were generally below 6% whereas limits of detection for each element were below 0.069 microg g(-1). In the presence of reciprocal interference the standard addition method considerably improved the resolution of the voltammetric technique, even for very high element concentration ratios. After being set up on the standard reference materials the analytical procedure was transferred and applied to commercial samples of meal and soil samples taken from sites devoted to agricultural practice. A critical comparison with graphite furnace atomic-absorption spectroscopy is also discussed.
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PMID:Overlapping voltammetric peaks--an analytical procedure for simultaneous determination of trace metals. Application to food and environmental matrices. 1567 34

A simple and rapid microwave-assisted extraction (MAE) technique has been developed for the determination of water-soluble inorganic species (cations: Na+, NH4+, K+, Ca2+ and Mg2+ and anions: F-, Cl-, NO3-, PO4(3-) and SO4(2-)) in airborne particulate matter. The analytes were extracted under different treatment conditions such as microwave power and extraction time. They were quantified using ion chromatography. The observed concentrations and recovery yields obtained under different conditions were compared. The results of a comparison between this MAE and sonication using NIST SRM 1648 are also given in this paper. The optimized MAE technique gave results in good agreement with the values obtained by the sonication. For some ions, for example Mg2+ and K+, recovery was low with both techniques. The results demonstrated that the optimized MAE is fast and efficient compared with conventional ultrasonic extraction. Urban airborne particles were collected and subjected to the MAE followed by the IC analysis to determine the relative proportions of different water-soluble inorganic species. These results are briefly discussed.
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PMID:Evaluation of a microwave-assisted extraction technique for determination of water-soluble inorganic species in urban airborne particulate matter. 1582 20

A technique is described for the determination of total gaseous lead in the atmosphere by honeycomb denuder collection, followed by an electrothermal atomic absorption spectrometry (ETAAS) measurement. The collection efficiency of the honeycomb denuder in which a solution containing 2% HNO3/2% glycerine/1% ammonium dihydrogenphosphate was coated for trapping the gaseous lead in the atmosphere was 98.8%. The linear absorbance response was obtained for a concentration range of 0-1.39 microg m(-3) of lead in the atmosphere. A precision of 4.8% RSD (peak-height absorbance, n = 11) for an aqueous solution of 1 ng of lead standard, characteristic masses (CM) of 23 pg and detection limit (3sigma) of 54 pg for an aqueous solution of 0.01 ng lead standard was achieved with 100 microg ammonium dihydrogenphosphate as a chemical modifier. The average recovery of lead in three standard samples prepared by the independent digestion of NIST SRM 1648 (Urban Particulate Matter) using our analytical system was 97.8%. The total content of the gaseous lead in the atmosphere of our laboratories was 0.35-0.38 microg m(-3).
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PMID:Determination of total gaseous lead in the atmosphere by honeycomb denuder/electrothermal atomic absorption spectrometry. 1636 69

Previously we have shown that TGF-beta1 protects murine L929 fibroblasts from TNF/ActD-mediated cell death by inducing the expression of an extracellular matrix TNF-resistance triggering (TRT) protein. TRT promotes TNF-resistance via activation of tyrosine and serine/threonine kinases in L929 cells. To examine the presence of TRT activity in serum (designated STRT), human sera were diluted, treated with or without PMSF and subjected to sequential ammonium sulfate precipitation (ASP). Aliquots of the ASP protein fractions were coated onto 96-well plates, followed by thorough washing. When L929 cells were seeded and cultured on the wells coated with STRT proteins, these cells resisted killing by TNF, TNF/ActD, doxorubicin and serum deprivation, but not by anti-Fas/ActD, staurosporine and ActD. STRT activity was found at the 15% ASP fraction of untreated sera, but shifted to the 20% ASP fraction of PMSF-treated sera. Two likely STRT proteins of approximately 226 and 265 kDa were found in these fractions, compared to the corresponding nonfunctional ASP fractions. Functionally, STRT was inactivated by trypsin, but not by 5 M salt, various serine and/or cysteine protease inhibitors, and antibodies against fibronectin, vitronectin, C1q, histidine-rich glycoprotein, CD44, chondroitin sulfate and hyaluronic acid. STRT failed to alter the expression of proteins involved in apoptosis such as RIP, ICH-1L, BCL-X, TIAR and IkappaBalpha, and could not induce IkappaBalpha degradation. The induced TNF-resistance could be reversed by treatment of STRT-stimulated cells with testicular hyaluronidase, as well as with tyrosine kinase inhibitors tyrophostin, lavendustin A and AG-490 (a selective inhibitor of JAK2 kinase). However, the STRT function could not be blocked by the MEK kinase inhibitor PD98059 and the NF-kappaB inhibitors curcumin and a synthetic inhibitor peptide for NF-kappaB translocation. Together, our data suggest that tyrosine kinase activation is involved in the STRT-mediated resistance to TNF and TNF/ActD in L929 cells.
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PMID:Characterization of serum adhesive proteins that block tumor necrosis factor-mediated cell death. 1646 90

The concentrations of metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in street sediment samples were determined by flame atomic absorption spectrometry (FAAS) using the modified BCR (the European Community Bureau of Reference) sequential extraction procedure. According to the BCR protocol for extracting the metals from the relevant target phases, 1.0 g of specimen of the sample was treated with 0.11 M acetic acid (exchangeable and bound to carbonates), 0.5M hydroxylamine hydrochloride (bound to iron- and manganese-oxides), and 8.8M hydrogen peroxide plus 1M ammonium acetate (bound to sulphides and organics), sequentially. The residue was treated with aqua regia solution for recovery studies, although this step is not part of the BCR procedure. The mobility sequence based on the sum of the BCR sequential extraction stages was: Cd approximately Zn ( approximately 90%)>Pb ( approximately 84%)>Cu ( approximately 75%)>Mn ( approximately 70%)>Co ( approximately 57%)>Ni ( approximately 43%)>Cr ( approximately 40%)>Fe ( approximately 17%). Enrichment factors as the criteria for examining the impact of the anthropogenic emission sources of heavy metals were calculated, and it was observed that the highest enriched elements were Cd, Pb, and Zn in the dust samples, average 190, 111, and 20, respectively. Correlation analysis (CA) and principal component analysis (PCA) were applied to the data matrix to evaluate the analytical results and to identify the possible pollution sources of metals. PCA revealed that the sampling area was mainly influenced from three pollution sources, namely; traffic, industrial, and natural sources. The results show that chemical sequential extraction is a precious operational tool. Validation of the analytical results was checked by both recovery studies and analysis of the standard reference material (NIST SRM 2711 Montana Soil).
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PMID:Fractionation of metals in street sediment samples by using the BCR sequential extraction procedure and multivariate statistical elucidation of the data. 1646 57

Aberrant DNA methylation patterns resulting in gene transcriptional repression are observed in numerous cancers. Decitabine, a DNA methyltransferase inhibitor, is being clinically evaluated in patients with hematologic malignancies and solid tumors. Decitabine is rather unstable and decomposes to 1-beta-D-2'-deoxyribofuranosyl-3-guanylurea under basic conditions and several additional unknown products under neutral conditions. This has greatly limited application of pharmacokinetic assays to clinical development of decitabine. In this paper, a high-performance liquid chromatography/ultraviolet multi-stage mass spectrometry (HPLC-UV-MSn) study of the decomposition of decitabine in water and human plasma revealed that these previously unknown products are isomers of the intermediates formyl-1-beta-D-2'-deoxyribofuranosyl-3-guanylurea and 1-beta-D-2'-deoxyribofuranosyl-3-guanylurea. A HPLC tandem mass spectrometry (MS/MS) method for the determination of decitabine concentrations in human and rat plasma has been developed. This method was based on a specific fragmentation pathway of the molecular ion of decitabine at m/z 229 to generate a unique fragment ion at m/z 113 under collision-induced dissociation. Separation of decitabine and the stable internal standard dihydro-5-aza-cytidine from the endogenous interfering substance in plasma extract was carried out on a C18 Aquasil column under an isocratic elution with a mobile phase consisting of 5% water/acetonitrile and 10 mM ammonium formate. The detection of decitabine was via selected reaction monitoring (SRM, 229 > 113), and its ionization was enhanced by post-column addition of acetonitrile. Effects of sample preparation and handling parameters on the stability of decitabine were also evaluated in human plasma at various temperatures. The accuracy and precision of this assay showed a coefficient of variation of <15% over the range of 0.5-25 ng for rat plasma and 0.1-25 ng for human plasma injected on-column. Pharmacokinetics of decitabine in rats following intravenous doses of 1.0 and 5.0 mg/kg were characterized. In the rat, plasma concentration-time profiles were found to follow a biexponential decline and the pharmacokinetics was dose-independent. Application of this decitabine pharmacokinetic assay to human studies is therefore justified and ongoing.
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PMID:Characterization of decomposition products and preclinical and low dose clinical pharmacokinetics of decitabine (5-aza-2'-deoxycytidine) by a new liquid chromatography/tandem mass spectrometry quantification method. 1652 29

A 234U and 230Th determination method based on an extraction chromatographic separation on a flow injection system coupled to a quadruple ICP-MS was developed. Two-milliliter UTEVA (Eichrom Co.) cartridges were applied as separation tool and 236U and 229Th as spikes. Loading and washing steps were carried out in 3 M HNO3 solution and 0.05 M ammonium oxalate applied to elute both uranium and thorium. The method was applied initially to the IAEA-327 soil reference sample and NIST SRM 4357 ocean sediment reference material, with the obtained 234U and 230Th concentrations in agreement with the reference levels. Samples from a deep-sea sediment core (2450 m water depth) were analyzed and based on 230Th/234U dating, a mean sedimentation rate of 3.3 cm ky(-1) was calculated. Samples from two sediment layers were also dated by 14C-AMS and the observed ages agree with the 230Th/234U results.
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PMID:234U and 230Th determination by FIA-ICP-MS and application to uranium-series disequilibrium in marine samples. 1654 93

Cystic fibrosis (CF) is a disease produced by mutations in the CFTR channel. We have previously reported that the CFTR chloride transport activity indirectly regulates the differential expression of several genes, including SRC and MUC1. Here we report that MT-ND4, a mitochondrial gene encoding a subunit of the mitochondrial Complex I (mtCx-I), is also a CFTR-dependent gene. A reduced expression of MT-ND4 was observed in CFDE cells (derived from a CF patient) when compared to CFDE cells ectopically expressing wild-type CFTR. The differential expression of MT-ND4 in CF was confirmed by RT-PCR. In situ hybridizations of deparaffinized human lung tissue slices derived from wt-CFTR or CF patients also showed downregulation of ND4 in CF. In addition, the CFTR chloride transport inhibitors glibenclamide and CFTR(inh)-172 also reduced MT-ND4 expression in CFDE cells ectopically expressing wt CFTR. These results suggest that the CFTR chloride transport activity indirectly up-regulates MT-ND4 expression.
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PMID:The expression of the mitochondrial gene MT-ND4 is downregulated in cystic fibrosis. 1738 98

Separation of metformin and glibenclamide was achieved within a single chromatographic run on a Zorbax CN column, under isocratic conditions, using acetonitrile and aqueous component (0.01 moles/L ammonium acetate adjusted at pH 3.5 with acetic acid) in volumetric ratio 1/1. Plasma sample preparation is based on protein precipitation by means of organic solvent addition. 1,3,5-Triazine-2,4,6-triamine (IS1) was used as internal standard for metformin, while gliquidone (IS2) played the same role for glibenclamide. Detection was performed with an ion trap mass analyzer, using atmospheric pressure chemical ionization (APCI). A single MS stage was used for detection of metformin and IS1, by extracting ion chromatograms corresponding to molecular ions. MS/MS detection in the SRM mode was used for glibenclamide (m/z transition from 494 to 369 Da) and IS2 (m/z transition from 528 to 403 Da). The method produces linear responses up to 2000 ng/mL for metformin and 400 ng/mL for glibenclamide, respectively. Low limits of quantification were found in the 40 ng/mL range for metformin and at the 4 ng/mL level for glibenclamide. Precision was characterized by relative standard deviations (RSD%) below 9%. The analytical method was successfully applied to a single dose, open-label, randomized, two-period, two-sequence, crossover bioequivalence study of two commercially available anti-diabetic combinations containing 400 mg metformin and 2.5 mg of glibenclamide per coated tablet.
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PMID:Simultaneous assay of metformin and glibenclamide in human plasma based on extraction-less sample preparation procedure and LC/(APCI)MS. 1750 48

Type-2 diabetes is a disorder characterized by disrupted insulin production leading to high blood glucose levels. To control this disease, combination therapy is often used. Hypoglycemic agents such as metformin, glipizide, glyburide, repaglinide, rosiglitazone, nateglinide, and pioglitazone are widely prescribed to control blood sugar levels. These drugs provide the basis for the development of a quantitative multianalyte bioanalytical method. As an example, a highly sensitive and selective multi-drug method based on liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed. This rapid, automated method consists of protein precipitation of 20 microL of plasma coupled with gradient HPLC elution of compounds using 10 mM ammonium formate buffer and 0.1% formic acid in acetonitrile as the mobile phases. MS/MS detection was performed using turbo ion spray in the positive ion multiple reaction monitoring (SRM) mode. A lower limit of quantitation (LLQ) in a range of 1.0-5.0 ng/mL was achieved for all analytes. The linearity of the method was observed over a 500-fold dynamic range. Drug recoveries ranged from 86.2 to 94.2% for all analytes of interest. Selectivity, sample dilution, intra-day and inter-day accuracy and precision, and stability assessment were evaluated for all compounds.
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PMID:Multi-component plasma quantitation of anti-hyperglycemic pharmaceutical compounds using liquid chromatography-tandem mass spectrometry. 1768 3


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