| 1. |
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| 2. |
- Anderot, Maria, et al.
(författare)
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Determination of dissociation constants between polyelectrolytes and proteins by affinity capillary electrophoresis
- 2009
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 877:10, s. 892-896
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Tidskriftsartikel (refereegranskat)abstract
- In this manuscript we report the binding affinity between two model proteins, human serum albumin (HSA) and ribonuclease A (RNase A), and negatively charged polyelectrolytes, two different heparin fractions and dextran sulfate, by means of partial filling and affinity capillary electrophoresis. The apparent dissociation constants, K-d, obtained by use of the partial-filling method, between HSA and heparin (17 kDa), heparin (3 kDa) and dextran sulfate (8 kDa) were 33 and 307 mu M, respectively. A new method was developed to determine affinities that take in account different migration directions between the protein and the polyelectrolyte, which was required to study RNase A. By use of this affinity capillary electrophoresis two K-d values were observed for the interaction between RNase A and heparin 17 kDa, yielding a high affinity binding with K-d1 0.0075 mu M, and a lower affinity binding with K-d2 8.7 mu M. For dextran sulfate 8 kDa these K-d values were 0.027 and 10.4 mu M, respectively. Heparin 3 kDa only showed a single K-d value of 0.52 mu M. The results show that the magnitude of the binding affinity depends on the type of polyelectrolyte and its molecular weight. (C) 2009 Elsevier B.V. All rights reserved.
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| 3. |
- Arvidsson, Björn, et al.
(författare)
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Online capillary solid phase extraction and liquid chromatographic separation with quantitative tandem mass spectrometric detection (SPE-LC-MS/MS) of ximelagatran and its metabolites in a complex matrix.
- 2009
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 877:3, s. 291-297
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Tidskriftsartikel (refereegranskat)abstract
- This work presents the development and validation of a fully automated quantitative analysis method of melagatran, its prodrug ximelagatran, and its major metabolites for the study of drug behavior in biofluids. The method involves online sample clean-up and enrichment on a C4 capillary column followed by separation on a capillary C18 column. Electrospray ionization tandem mass spectrometric detection in positive ion mode was performed with multiple reactions monitoring of eight different transients, divided into two time segments with four transients each. The structural similarity, the complexity of the matrix (pig liver extract) and the formation of isobaric fragment ions, made efficient chromatographic separation necessary. The analysis method provides valid accuracy (<9%; RSD%), precision (<8%; RSD%), linearity (<1.2 nM–1 μM; R2 > 0.999), limit of quantitation (<3.6 nM), retention repeatability (<1.2%; RSD%), selectivity, as well as analyte and column stabilities over a wide concentration range.
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| 4. |
- Bennemo, Mia, et al.
(författare)
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A chromatographic method for determination of supercoiled plasmid DNA concentration in complex solutions.
- 2009
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 877:24, s. 2530-6
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Tidskriftsartikel (refereegranskat)abstract
- A method for determination of the plasmid DNA concentration with subsequent analysis of the ratio supercoiled to open circular form is presented. The method is suitable for samples from all steps of the manufacturing process, from fermentation to final product. The analysis consists of size exclusion chromatography, followed by analytical thiophilic aromatic chromatography. In the first step, the plasmid DNA concentration is determined by group separation, including removal of RNA and other impurities, within less than 2 min. The limit of detection and quantification was 0.28 and 0.83 microg/ml, respectively. The precision of the method is high, providing a coefficient of variation as low as below 2%. In the second step, the ratio of open circular to supercoiled plasmid DNA is determined following separation of the two plasmid DNA isoforms with a linear salt gradient. The precision of the second step was evaluated using serial injections of aliquots of a sample stock solution. In comparison with the two most commonly used methods, the developed analysis was found to be significantly more accurate than agarose gel electrophoresis and equivalent to capillary gel electrophoresis. The combined methods for quantification and control of homogeneity of plasmid DNA presented here enable reliable and precise analysis at all steps of the manufacturing process.
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| 5. |
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| 6. |
- Chadt, J, et al.
(författare)
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Monitoring of dimethyl sulphate-induced N3-methyladenine, N7-methylguanine and O6-methylguanine DNA adducts using reversed-phase high performance liquid chromatography and mass spectrometry
- 2008
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 867, s. 43-48
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Tidskriftsartikel (refereegranskat)abstract
- This work describes the determination of N3-methyladenine, N7-methylguanine and O6-methylguanine adducts in dimethyl sulphate-treated salmon-testes DNA employing reversed-phase high performance liquid chromatography (RP-HPLC) with UV–vis detection, followed by mass-spectrometric verification using electrospray ionisation in positive mode ESI(+). Within validation parameters, accuracy, precision, calibration parameters, limit of detection (LOD) and quantitation (LOQ) as well as stability of standard stock solutions were tested and presented for UV/vis detection. The limit of detection (LOD) was found to be 0.1 ng/mL for N3-methyladenine and 0.2 ng/mL for both N7-methylguanine and O6-methylguanine (S/N = 3). The limit of quantitation (LOQ) was found to be 0.5 ng/mL for all measured compounds, (S/N = 10). Quantitative results were obtained for each substance based on eight-point calibration. Intra- and inter-day precisions were within 1.73–6.96 and 2.26–7.58%, respectively, and correlation coefficients of calibration curves (R2) ranged from 0.9992 to 0.9997. Relative proportion of N7-methylguanine was accounted for 61.53 ± 2.97% (R.S.D. = 4.8), N3-methyladenine for 38.19 ± 2.99% (R.S.D. = 9.6) and O6-methylguanine for 0.29 ± 0.02% (R.S.D. = 5.1), respectively. The application of the above-mentioned techniques provides a valuable contribution for simultaneous determination of methylated DNA adducts, and may represent a suitable approach for similar monitoring/screening studies.
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| 7. |
- Claeson Bohnstedt, Kristina, et al.
(författare)
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Porous graphitic carbon chromatography-tandem mass spectrometry for the detection of isoprostanes in human cerebrospinal fluid
- 2005
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 827:1, s. 39-43
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Tidskriftsartikel (refereegranskat)abstract
- F2-isoprostanes are produced by the non-enzymatic peroxidation of arachidonic acid in membrane phospholipids. This paper describes a new method for the determination of all four classes of F2-isoprostanes in human cerebrospinal fluid (CSF) involving separation on a 1 mm × 150 mm porous graphitic carbon (PGC) column and detection by triple quadrupole mass spectrometry in negative-ion electrospray mode. The sample pre-treatment consisted of an ultrafiltration step, following which 300 μl of CSF sample could be injected directly onto a 1 mm × 10 mm PGC guard column functioning as a trap for the analytes. The loading solvent was Milli-Q water at 125 μl/min. After 3 min, the sample was switched into the separation column. The F2-isoprostanes were separated in 20 min using a linear solvent gradient comprising water, methanol, acetonitrile and ammonium hydroxide at a pH of 9.5 and a flow of 50 μl/min The limit of detection (calculated as 3S/N) was approximately 40 pM (14 pg/ml). The assay was linear within the examined range (18–450 pg/ml), using CSF spiked with iPF2α-III standard (r2 > 0.995). Repeatability data were calculated for CSF spiked to 90 pg/ml and the relative standard deviation (RSD) obtained was 3% (n = 6).
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| 8. |
- Dorlo, Thomas P C, et al.
(författare)
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Development and validation of a quantitative assay for the measurement of miltefosine in human plasma by liquid chromatography-tandem mass spectrometry.
- 2008
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 865:1-2, s. 55-62
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Tidskriftsartikel (refereegranskat)abstract
- A sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for the quantification of miltefosine is presented. A 250 microL human EDTA plasma aliquot was spiked with miltefosine and extracted by a solid-phase extraction method. Separation was performed on a Gemini C18 column (150 mm x 2.0 mm I.D., 5 microm) using an alkaline eluent. Detection was performed by positive ion electrospray ionization followed by triple-quadrupole mass spectrometry. The assay has been validated for miltefosine from 4 to 2000 ng/mL using 250 microL human EDTA plasma samples. Results from the validation demonstrate that miltefosine can be accurately and precisely quantified in human plasma. At the lowest level, the intra-assay precision was lower than 10.7%, the inter-assay precision was 10.6% and accuracies were between 95.1 and 109%. This assay is successfully used in a clinical pharmacokinetic study with miltefosine.
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| 9. |
- Fotoohi, K, et al.
(författare)
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Interference of 7-hydroxymethotrexate with the determination of methotrexate in plasma samples from children with acute lymphoblastic leukemia employing routine clinical assays
- 2005
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Ingår i: Journal of Chromatography. B. - : Elsevier BV. - 1873-376X .- 1570-0232. ; 817:2, s. 139-144
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Tidskriftsartikel (refereegranskat)abstract
- The accuracy of two clinical assays, the enzyme-multiplied immunoassay (EMIT) and fluorescence polarization immunoassay (FPIA2), universally employed for measurement of plasma levels of methotrexate (MTX) in children administered a high dose of this drug for treatment of acute lymphoblastic leukemia was evaluated here. Because of its superior specificity, sensitivity, and precision, high performance liquid chromatography (HPLC) was selected as the reference method with which the other two procedures were compared using approximately 420 different plasma samples for method comparison. 7-Hydroxymethotrexate (7-OHMTX), the major plasma metabolite of MTX, that can be detected in plasma at relatively high concentrations for long periods following infusion of a high dose of MTX, was also quantitated by HPLC. Forty-two and 66 h after infusion, the plasma level of MTX was overestimated in 2% and 3% of the samples by the FPIA2 procedure in 5% and 31% by the EMIT assay. The overall correlation coefficients (r(2)) for the values obtained by FPIA2 or EMIT versus those based on HPLC were 0.989 and 0.663, respectively. The presence of 7-OHMTX exerted a highly significant influence (p = 0.0007 as determined by the unpaired t-test) on MTX measurement by the EMIT assay. We conclude that the rapid automated procedures routinely used at present and in particular EMIT, suffer from cross-reactivity with metabolites of MTX. Thus, the relatively high percentage of samples in which the level of MTX is overestimated at check-points by EMIT may result in longer periods of hospitalization, higher costs and prolonged administration of elevated doses of "rescue" leucovorin with an increased risk for relapse.
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| 10. |
- Garscha, Ulrike, et al.
(författare)
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Enantiomeric separation and analysis of unsaturated hydroperoxy fatty acids by chiral column chromatography-mass spectrometry
- 2008
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 872, s. 90-98
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Tidskriftsartikel (refereegranskat)abstract
- Hydroperoxides of 18:2n-6 and 20:4n-6 were obtained by autoxidation and photooxidation. The enantiomers Were separated as free acids (Reprosil Chiral-NR column, eluted with hexane containing 1-1.2% alcoholic modifier) and analyzed by on line UV detection (234 nm) and liquid chromatography-MS/MS/MS of carboxylate anions (A(-) -> (A(-)-18) -> full scan) in an ion trap. The combination of UV and MS/MS/MS analysis facilitated identification of hydroperoxides even in complex mixtures of autoxidized or photooxidized fatty acids. The signal intensities increased about two orders of magnitude by raising the isolation width of A(-) from 1.5 amu to 5 or 10 amu for cis-trans conjugated hydroperoxy fatty acids, and one order of magnitude of more for non-conjugated hydroperoxy fatty acids. The S enantiomer of 8-, 9-, 10-, and 13-hydroperoxyoctadecadienoic acids and the S enantiomer of cis-trans conjugated hydroperoxyeicosatetraenoic acids eluted before the corresponding R enantiomer with two exceptions (11-hydroperoxylinoleic acid and 8-hydroperoxyeicosa-5Z,9E,11Z,14Z-tetraenoic acid). The separation of enantiomers or regioisomers could be improved by the choice of either isopropanol or methanol as alcoholic modifier.
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| 11. |
- Grey, Carl, et al.
(författare)
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Development of a high performance anion exchange chromatography analysis for mapping of oligosaccharides
- 2009
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 877:20-21, s. 1827-1832
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Tidskriftsartikel (refereegranskat)abstract
- In the present study a HPAEC-PAD method is described that was developed for monitoring the consistency of N-glycosylation during the production and purification of recombinant proteins and monoclonal antibodies. The method successfully separated 18 neutral and sialylated oligosaccharides. Results obtained were compared with MALDI-TOF MS and it was shown that both methods gave similar results. in addition, a method validation was performed showing that the HPAEC-PAD analysis was well suited for the mapping and characterization of oligosaccharides. The method was found to be robust and additionally the precision was significantly better compared to the MALDI-TOF MS method.
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| 12. |
- Hober, Sophia, et al.
(författare)
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Protein A chromatography for antibody purification
- 2007
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 848:1, s. 40-47
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Forskningsöversikt (refereegranskat)abstract
- Staphylococcal protein A (SPA) is one of the first discovered immunoglobulin binding molecules and has been extensively studied during the past decades. Due to its affinity to immunoglobulins, SPA has found widespread use as a tool in the detection and purification of antibodies and the molecule has been further developed to one of the most employed affinity purification systems. Interestingly, a minimized SPA derivative has been constructed and a domain originating from SPA has been improved to withstand the harsh environment employed in industrial purifications. This review will focus on the development of different affinity molecules and matrices for usage in antibody purification.
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| 13. |
- Homer, Natalie Z M, et al.
(författare)
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Quantitative analysis of RU38486 (mifepristone) by HPLC triple quadrupole mass spectrometry
- 2009
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 877:5-6, s. 497-501
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Tidskriftsartikel (refereegranskat)abstract
- A sensitive liquid chromatography-mass spectrometric method was validated for the quantification of RU38486 (mifepristone) in human and murine plasma. The analyte and internal standard (alfaxolone) were extracted by liquid-liquid extraction with diethyl ether, resolved on a C18 column using gradient elution with methanol and ammonium acetate and detected after positive electrospray ionization (m/z 430-->372; m/z 333-->297, respectively). Quantification was linear over the range 0.5-500ng (r(2)>0.997), precise and accurate (intra-assay RSD
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| 14. |
- Idborg, Helena, et al.
(författare)
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Metabolic fingerprinting of rat urine by LC/MS. : Part1. Analysis by hydrophilic interaction liquid chromatography-electrospray ionization mass spectrometry
- 2005
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Ingår i: Journal of Chromatography B. - : Elsevier BV. - 1387-2273 .- 1878-5603 .- 1570-0232 .- 1873-376X. ; 828:1-2, s. 9-13
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Tidskriftsartikel (refereegranskat)abstract
- Complex biological samples, such as urine, contain a very large number of endogenous metabolites reflecting the metabolic state of an organism. Metabolite patterns can provide a comprehensive signature of the physiological state of an organism as well as insights into specific biochemical processes. Although the metabolites excreted in urine are commonly highly polar, the samples are generally analyzed using reversed-phase liquid chromatography mass spectrometry (RP-LC/MS). In Part I of this work, a method for detecting highly polar metabolites by hydrophilic interaction liquid chromatography-electrospray ionization mass spectrometry (HILIC/ESI-MS) is described as a complement to RP-LC/ESI-MS. In addition, in an accompanying paper (Part 2), different multivariate approaches to extracting information from the resulting complex data are described to enable metabolic fingerprints to be obtained. The coverage of the method for the screening of as many metabolites as possible is highly improved by analyzing the urine samples using both a C-18 column and a ZIC (R)-HILIC column. The latter was found to be a good alternative when analyzing highly polar compounds, e.g., hydroxyproline and creatinine, to columns typically used for reversed-phase liquid chromatography. (c) 2005 Elsevier B.V. All rights reserved.
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| 15. |
- Ihalin, R, et al.
(författare)
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Characterization of immunoaffinity purified peptidoglycan-associated lipoprotein of Actinobacillus actinomycetemcomitans.
- 2006
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 831:1-2, s. 116-125
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Tidskriftsartikel (refereegranskat)abstract
- Peptidoglycan-associated lipoprotein (PAL) is a highly conserved structural outer membrane protein among Gram-negative bacteria. In some species, it is proinflammatory and released extracellularly. We purified a newly identified PAL (AaPAL) of a periodontal pathogen Actinobacillus actinomycetemcomitans by using AaPAL antipeptide antibodies coupled to immunoaffinity chromatography column. No protein impurities originating in A. actinomycetemcomitans were found in the final product. Sera from patients infected by A. actinomycetemcomitans recognized the purified AaPAL. The present purification method seems to be suitable for isolation of AaPAL and probably PALs of other bacterial species, and applicable in studies investigating proinflammatory mechanisms of A. actinomycetemcomitans.
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| 16. |
- Johannesson, Nina, et al.
(författare)
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On-Line Biological Sample Cleanup for Electrospray Mass Spectrometry Using Sol-Gel Columns
- 2006
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 842:1, s. 70-74
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Tidskriftsartikel (refereegranskat)abstract
- Using a slight overpressure, a urine sample is loaded onto a monolithic photopolymerized sol-gel column that has been derivatized with hydrophobic carbon chains and then the complex urine matrix is washed with aqueous solution. A buffer containing organic solvent is used to elute the adsorbed peptides by an applied voltage and the sample is then introduced into a mass spectrometer by sheath flow electrospray. The importance of desalting this type of sample is demonstrated by an experiment that shows that the signal intensity of a test solution with neurotensin, sprayed directly into the mass spectrometer, decreased from 4.5 x 10(4) Cps to no detectible signal when just 10% urine is added to the sample solution. We suggest that this procedure may find general application for desalting biological samples prior to mass spectrometric analysis.
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| 17. |
- Kusano, Miyako, et al.
(författare)
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Application of a metabolomic method combining one-dimensional and two-dimensional gas chromatography-time-of-flight/mass spectrometry to metabolic phenotyping of natural variants in rice
- 2007
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Ingår i: Journal of chromatography. B. - Amsterdam : Elsevier. - 1570-0232 .- 1873-376X. ; 855:1, s. 71-79
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a comprehensive method combining analytical techniques of one-dimensional (I D) and two-dimensional (GC x GC) gas chromatography-time-of-flight (TOF)-mass spectrometry. This method was applied to the metabolic phenotyping of natural variants in rice for the 68 world rice core collection (WRC) and two other varieties. Ten metabolites were selected as metabolite representatives, and the selected ion current of each metabolite peak obtained from both techniques were statistically compared. Our method of combining I D- and GC x GC-TOF/MS is useful for the metabolic phenotyping of natural variants in rice for further studies in breeding programs.
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| 18. |
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| 19. |
- Lv, Yong-Qin, et al.
(författare)
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One-step rapid determination and purification of puerarin from Radix puerariae by n-octylamine-modified poly(methacrylate-co-ethylene dimethacrylate) monolith
- 2008
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 871:1, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- n-Octylamine-modified poly(methacrylate-co-ethylene dimethacrylate) monoliths were prepared for rapid screening, determination and one-step purification of puerarin from Radix puerariae (a crude extract of the root of Pueraria lobata). The modified monolith showed a specific surface area of 17.8 m(2) g(-1) an average pore size of 0.76 mu m and a total porosity of 60.8%. Fast separation of R. puerariae crude extract was achieved within 5 min at a flow velocity of 722 cm h(-1) resulting in a puerarin Purity of 97%, with a recovery of 85%. This demonstrates the potential of n-octylamine-modified poly(methacrylate-co-ethylene dimethacrylate) monolith for the rapid analysis and separation of isoflavonoids. Preparative scale sample loading (12 mg in 2 mL) resulted in a purity of 95%, and a recovery of about 69%. HPLC, FTIR, MS and H-1 NMR spectroscopy were used for the characterization and quantification of puerarin in isolated fraction.
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| 20. |
- Malm, Mikaela, et al.
(författare)
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Determination of eflornithine enantiomers in plasma, by solid-phase extraction and liquid chromatography with evaporative light-scattering detection
- 2007
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X .- 1387-2273 .- 1878-5603. ; 846:1-2, s. 98-104
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Tidskriftsartikel (refereegranskat)abstract
- A bioanalytical method for determination of eflornithine (DFMO) in 1000 μL human plasma has been developed and validated. DFMO and the internal standard (IS) were analysed by liquid chromatography with evaporative light-scattering detection (ELSD). Separation was performed on a Chirobiotic TAG (250 mm × 4.6 mm) column with ethanol (99.5%):0.01 mol/L acetic acid-triethylamine buffer at the rate of 25:75% (v/v) with flow rate of 1.0 mL/min. For d-DFMO in plasma the inter-assay precision was 6.5% at 75 μmol/L, 6.6% at 375 μmol/L and 5.8% at 750 μmol/L. For l-DFMO in plasma the inter-assay precision was 10.4% at 75 μmol/L, 6.5% at 375 μmol/L and 5.0% at 750 μmol/L. The lower limit of quantification (LLOQ) was determined to 25 μmol/L where the precision was 4.3% and 5.7%, respectively.
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| 21. |
- Malmström, Johan, et al.
(författare)
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Quantitative proteomic analysis of fibroblast nuclear proteins after stimulation with mitogen activated protein kinase inhibiting heparan sulfate
- 2005
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Ingår i: Journal of Chromatography. B. - : Elsevier BV. - 1873-376X .- 1570-0232. ; 815:1-2, s. 333-342
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Tidskriftsartikel (refereegranskat)abstract
- Certain structures of heparan sulfate (HS) inhibit cell proliferation of fibroblasts. Whether this inhibition is dependent on inhibition of mitogenic signaling pathways or nuclear translocation of HS is unknown. In this study we investigated possible mechanism(s) and structural requirements by which antiproliferative glycosaminoglycans exert their effects on mitogen-activated protein kinase (MAP kinase) phosphorylation, a key intermediate in cell signaling, followed by quantitative proteomic analysis of nuclear proteins by stable isotope coded affinity tags, multidimensional chromatography and tandem mass spectrometry. Serum starved human lung fibroblasts were stimulated with serum, platelet derived growth factor (PDGF-BB) or epidermal growth factor (EGF) in the presence of structurally different glycosaminoglycans. Antiproliferative heparan sulfate with a high content of 2-O-sulfated iduronic acid (IdoA-2SO4) and heavily sulfated glucosamine, and the structurally related glycosaminoglycan heparin inhibited significantly serum stimulated MAP kinase phosphorylation, by at least 80% when stimulated by serum and HS6. We hypothesized that the inhibition of the MAP kinase pathway will have effect in the nuclear proteome. Therefore an isotope coded affinity tag (ICAT) reagent labeling of nuclear proteins and tandem mass spectrometry was applied, resulting in the identification and quantification of 206 proteins. Several nuclear proteins were found to be induced or repressed due to HS stimulation, where the repression EBNA-2 co-activator and the induction of PML protein were of special interest. These results show that heparan sulfate with high content of (IdoA-2SO4) and heavily sulfated glucosamine specifically inhibits MAP kinase activation with a subsequent change in the nuclear proteome of the fibroblast.
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| 22. |
- Nanni, Paolo, et al.
(författare)
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A label-free nano-liquid chromatography-mass spectrometry approach for quantitative serum peptidomics in Crohn's disease patients.
- 2009
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Ingår i: Journal of Chromatography. B. - : Elsevier BV. - 1873-376X .- 1570-0232. ; 877:27, s. 3127-3136
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Tidskriftsartikel (refereegranskat)abstract
- The identification of serum biomarkers for the diagnosis of inflammatory bowel diseases able to reduce the need for invasive tests represents a major goal in their therapy and follow-up. We report here a methodological approach for the evaluation of specific changes in the serum peptides abundance in healthy (H) and Crohn's disease (CD) subjects, based on a label-free LC ESI/Q-TOF differential mass spectrometry (MS) approach combined with targeted MS/MS analysis. The low molecular weight serum proteins were separated by RP nano-LC ESI/Q-TOF MS and the resulting datasets were aligned with msInspect software. The differently abundant peptides, evaluated using Proteios Software Environment, were identified by MS/MS analysis and database search. The identification of clusters of peptides resulting from proteins (such as fibrinogen-α) commonly involved in physiological processes lead to the evaluation of a possible role in CD of specific serum exoproteases. An assay based on synthetic peptides spiked into H, CD and ulcerative colitis (UC) serum samples as substrate, followed by MALDI MS and chemometric analysis of the metabolite patterns has been developed achieving a 100% discrimination between CD, UC and H subjects. The results are promising for the application of this approach as a simple tool for diagnostic aims and biomarker discovery in CD.
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| 23. |
- Niemelä, Perttu S., et al.
(författare)
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Bioinformatics and computational methods for lipidomics
- 2009
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Ingår i: Journal of chromatography. B. - : Elsevier. - 1570-0232 .- 1873-376X. ; 877:26, s. 2855-2862
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Tidskriftsartikel (refereegranskat)abstract
- Large amounts of lipidomics data are rapidly becoming available. However, there is a lack of tools capable of taking the full advantage of the wealth of new information. Lipid bioinformatics is thus an emerging need as well as challenge for lipid research. Lipid concentration changes in biological systems reflect regulation at multiple spatial and dynamic scales, e.g., biochemical reactions in the cells, intercellular lipid trafficking, changes in cell membrane composition, systemic lipid metabolism or lipid oxidation. In order to address the complexity of lipids and their regulation, four areas of bioinformatics need to be developed: (1) data processing and lipid identification, (2) statistical data analysis, (3) pathway analysis, and (4) lipid modeling in systems and biophysical contexts. In this paper we overview the current state of the lipid bioinformatics field as well as suggest few potential new areas of research.
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| 24. |
- Nilsson, Elin, 1979-, et al.
(författare)
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Pseudomonas aeruginosa infections are prevented in cystic fibrosis patients by avian antibodies binding Pseudomonas aeruginosa flagellin : Pseudomonas aeruginosa infections are prevented in cystic fibrosis patients by avian antibodies binding Pseudomonas aeruginosa flagellin
- 2007
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 856:1-2, s. 75-80
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Tidskriftsartikel (refereegranskat)abstract
- Pseudomonas aeruginosa (PA) is the main cause of morbidity and mortality in cystic fibrosis (CF) patients. CF patients with chronic PA infections have a more rapid deterioration of their lung function and the bacteria become impossible to eradicate from the lungs. Antibiotic resistance among PA strains in CF patients is steadily increasing. Specific chicken (IgY) antibodies against PA have been shown to have potential to prevent PA infections in CF. Anti-Pseudomonas IgY reduces PA adhesion to epithelia, but the mechanism has not been fully elucidated. To gain further insight into the prophylactic effect of these antibodies, the immunoreactivity was investigated by 2D electrophoresis of PA strains, immunoblotting and MALDI-TOF-MS. To confirm the identity of the proteins, the tryptic peptides were analyzed by MALDI-TOF-MS to accurately measure their monoisotopic masses as well as determine their amino acid sequences. In order to facilitate fragmentation of the peptides they were N-terminally or C-terminally labeled. Several strains were investigated and anti-Pseudomonas IgY was immunoreactive against all of these strains, which strengthens its potential as a prophylactic treatment against PA. Flagellin was identified as the major antigen. Flagellin is the main protein of the flagella and is crucial for establishing infections in hosts as well as being involved in PA chemotaxis, motility, adhesion and inflammation. Furthermore, secreted flagellin elicits an inflammatory response. In conclusion, anti-Pseudomonas IgY binds flagellin, which may prevent PA infections in CF patients by hindering host invasion.
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| 25. |
- Olsson, Jeanette, 1976-, et al.
(författare)
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Enantioseparation of Omeprazole and its Metabolite 5-Hydroxyomeprazole using Open Tubular Capillary Electrochromatography with Immobilized Avidin as Chiral Selector
- 2008
-
Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 875:1, s. 329-332
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Tidskriftsartikel (refereegranskat)abstract
- The present paper demonstrates the enantiomeric separation of omeprazole and its metabolite 5-hydroxyomeprazole performed with open tubular capillary electrochromatography (OT-CEC). The protein avidin was used as the chiral selector. Avidin was immobilized by a Schiffs base type of reaction where the protein was via glutaraldehyde covalently bonded to the amino-modified wall of a fused-silica capillary, 50 μm i.d. Both racemates were baseline resolved. Resolution was 1.9 and 2.3, respectively, using ammonium acetate buffer, pH 5.8, 5% methanol, with UV-detection. These values of resolution using OT-CEC are higher than earlier published results regarding chiral separation of omeprazole and 5-hydroxyomeprazole on packed CEC. The number of theoretical plates also indicated good separation efficiency.
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| 26. |
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| 27. |
- Potthast, Frank, et al.
(författare)
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The Mass Distance Fingerprint: A statistical framework for de novo detection of predominant modifications using high-accuracy mass spectrometry
- 2007
-
Ingår i: Journal of Chromatography. B. - : Elsevier BV. - 1873-376X .- 1570-0232. ; 854:1-2, s. 173-182
-
Tidskriftsartikel (refereegranskat)abstract
- We describe a statistical measure, Mass Distance Fingerprint, for automatic de novo detection of predominant peptide mass distances, i.e., putative protein modifications. The method's focus is to globally detect mass differences, not to assign peptide sequences or modifications to individual spectra. The Mass Distance Fingerprint is calculated from high accuracy measured peptide masses. For the data sets used in this study, known mass differences are detected at electron mass accuracy or better. The proposed method is novel because it works independently of protein sequence databases and without any prior knowledge about modifications. Both modified and unmodified peptides have to be present in the sample to be detected. The method can be used for automated detection of chemical/post-translational modifications, quality control of experiments and labeling approaches, and to control the modification settings of protein identification tools. The algorithm is implemented as a web application and is distributed as open source software.
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| 28. |
- Puerta, Angel, et al.
(författare)
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Novel adsorptive polyamine coating for enhanced capillary electrophoresis of basic proteins and peptides
- 2006
-
Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 838:2, s. 113-121
-
Tidskriftsartikel (refereegranskat)abstract
- In capillary electrophoresis (CE), the anionic and hydrophobic nature of the fused-silica capillary surface has long been known to present a problem in protein and peptide analysis. The use of capillary surface coating is one of the approaches to avoid the analyte-wall interactions. In this study, a new polymer, poly-LA 313, has been synthesized, physico-chemical characterized, and applied as polyamine coating for CE separations. The coating process is highly reproducible and provides fast separations of peptides and proteins in a few minutes and with high efficiency. The physically adsorbed polymer gives rise to a durable coating in the range of pH 2-10, in the presence of organic modifiers (acetonitrile and methanol) and with complex biological samples. The efficiency of the new cationic polymer was also tested performing protein and peptide separations with capillary electrophoresis-electrospray ionization-mass spectrometry (CE-ESI-MS).
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| 29. |
- Sahoo, Deepti, et al.
(författare)
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Immobilized metal affinity chromatography in open-loop simulated moving bed technology: purification of a heat stable histidine tagged beta-glucosidase.
- 2009
-
Ingår i: Journal of Chromatography. B. - : Elsevier BV. - 1873-376X .- 1570-0232. ; 877:16-17, s. 1651-1656
-
Tidskriftsartikel (refereegranskat)abstract
- Open-loop simulated moving bed (SMB) has been used for immobilized metal affinity chromatographic (IMAC) purification of his-tagged beta-glucosidase expressed in E. coli. A simplified approach based on an optimized single column protocol is used to design the open-loop SMB. A set of columns in the SMB represent one step in the chromatographic cycle i.e. there will be one set each of columns for load, wash, elution etc within the SMB. Only the wash and elution are operated with columns in sequence. The beta-glucosidase was purified to almost single band purity with a purification factor of 15 and a recovery of 91%. SMB-performance showed reduced buffer consumption, higher purification fold, a better yield and higher productivity.
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| 30. |
- Sirén, Heli, et al.
(författare)
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Capillary electrophoresis with UV detection and mass spectrometry in method development for profiling metabolites of steroid hormone metabolism
- 2008
-
Ingår i: Journal of chromatography. B. - : Elsevier. - 1570-0232 .- 1873-376X. ; 871:2, s. 375-382
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to develop a method for comprehensive profiling of metabolites involved in mammalian steroid metabolism. The study was performed using the partial filling micellar electrokinetic chromatography (PF-MEKC) technique for determination of endogenous low-hydrophilic steroids. The detection techniques in capillary electrophoresis were UV absorption and electrospray mass spectrometry (ESI-MS). Thirteen steroids were included in the method development, and the selected were metabolites involved in major pathways of steroid biosynthesis. Although only eight of them could be separated and detected with UV, they could be identified by ESI-MS using selected ion monitoring (SIM) technique. Tandem MS spectra were also collected. UV detection was more sensitive than MS due to better separation of compounds and the selective signal sensitivity. The lowest limits of detection were 10-100 ng/mL for cortisone, corticosterone, hydrocortisone and testosterone. The other steroids could be detected at 500-1000 ng/mL. The identification of cortisone, corticosterone, hydrocortisone, estrogen and testosterone were made in patient urine samples and their concentrations were 1-40 microg/L.
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| 31. |
- Soultani-Vigneron, S., et al.
(författare)
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Immobilisation of oligo-peptidic probes for microarray implementation : Characterisation by FTIR, Atomic Force Microscopy and 2D fluorescence
- 2005
-
Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 822:02-jan, s. 304-310
-
Tidskriftsartikel (refereegranskat)abstract
- Proteomic microarrays show a wide range of applications for the investigation of DNA-protein, enzyme-substrate as well as protein-protein interactions. Among many challenges to build a viable protein microarray, the surface chemistry that will allow to immobilised various proteins to retain their biological activity is of paramount importance. Here we report a chemical functionalisation method allowing immobilisation of oligo-peptides onto silica surface (porous silica, glass, thermal silicon dioxide). Substrates were first derivatised with a monofunctional silane allowing the elaboration of dense and uniform monolayers in highly reproducible way. Prior to the oligo-peptides grafting, this organic layer was functionalised with an amino-polyethyleneglycol. The coupling step of oligo-peptides onto functionalised supports is achieved through activation of the C-terminal function of the oligo-peptides. Chemical surface modifications were followed by FTIR spectroscopy, AFM measurements and fluorescence scanning microscopy. A systematic study of the oligo-peptide grafting conditions (time, concentration, solvent) was carried out to optimise this step. The oligo-peptides grafting strategy implemented in this work ensure a covalent and oriented grafting of the oligo-peptides. This orientation is ensured through the use of fully protected peptide except the terminal primary an-tine. The immobilized peptides will be then deprotected before biological recognition. This strategy is crucial to retain the biological activity of thousands of oligo-probes assessed on a microarray.
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| 32. |
- Stephanson, Nikolai, et al.
(författare)
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Accurate identification and quantification of 11-nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid in urine drug testing: Evaluation of a direct high efficiency liquid chromatographic-mass spectrometric method
- 2008
-
Ingår i: Journal of chromatography. B. - : Elsevier Science B.V., Amsterdam.. - 1570-0232 .- 1873-376X. ; 871:1, s. 101-108
-
Tidskriftsartikel (refereegranskat)abstract
- A direct liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method for measurement of urinary Delta(9)-tetrahydrocannabinol carboxylic acid (THCA) was developed. The method involved dilution of the urine sample with water containing H-2(9)-deuterated analogue as internal standard, hydrolysis with ammonia, reversed phase chromatography using a Waters ultra-performance liquid chromatography (UPLC (TM)) equipment with gradient elution, negative electrospray ionization, and monitoring of two product ions in selected reaction monitoring mode. The measuring range was 2-1000 ng/mL for THCA, and the intra- and inter-assay imprecision, expressed as the coefficient of variation, was below 5%. Influence from urine matrix on ionization efficiency was noted in infusion experiments, but was compensated for by the internal standard. Comparison with established gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry methods in authentic patient samples demonstrated accuracy in both qualitative and quantitative results. A small difference in mean ratios (similar to 15%) may be explained by the use of different hydrolysis procedures between methods. In conclusion, the high efficiency LC-MS/MS method was capable of accurately identify and quantify THCA in urine with a capacity of 14 samples per hour.
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| 33. |
- Sundqvist, Gustav, et al.
(författare)
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A general, robust method for the quality control of intact proteins using LC–ESI-MS
- 2007
-
Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 852:1-2, s. 188-194
-
Tidskriftsartikel (refereegranskat)abstract
- A simple and robust method for the routine quality control of intact proteins based on liquid chromatography coupled to electrospray ionization mass spectrometry (LC-ESI-MS) is presented. A wide range of prokaryotic and eukaryotic proteins expressed recombinantly in Escherichia coli or Pichia pastoris has been analyzed with medium- to high-throughput with on-line desalting from multi-well sample plates. Particular advantages of the method include fast chromatography and short cycle times, the use of inexpensive trapping/desalting columns, low sample carryover, and the ability to analyze proteins with masses ranging from 5 to 100 kDa with greater than 50 ppm accuracy. Moreover, the method can be readily coupled with optimized chemical reduction and alkylation steps to facilitate the analysis of denatured or incorrectly folded proteins (e.g., recombinant proteins sequestered in E. coli inclusion bodies) bearing cysteine residues, which otherwise form intractable multimers and non-specific adducts by disulfide bond formation.
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| 34. |
- Syren, Per-Olof, et al.
(författare)
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Milligram scale parallel purification of plasmid DNA using anion-exchange membrane capsules and a multi-channel peristaltic pump
- 2007
-
Ingår i: Journal of chromatography. B. - : Elsevier B.V.. - 1570-0232 .- 1873-376X. ; 856, s. 68-74
-
Tidskriftsartikel (refereegranskat)abstract
- A parallel chromatog. procedure for the purifn. of milligram amts. of plasmid DNA was developed. Initial studies showed that ion-exchange membrane capsules displayed high capacity for plasmid DNA. Interestingly, a weak anion exchanger (DEAE) proved to be superior to the strong quaternary ammonium group with respect to elution and regeneration properties and the 75 cm2 Sartobind D membrane capsule (MA75D, Sartorius) was selected for further studies. A method for reducing endotoxin levels by using CTAB as a precipitant was optimized. By introducing this step into the protocol, endotoxin levels could be reduced approx. 100-fold to ≤5 EU/mg plasmid. The parallel procedure was set up on a multi-channel peristaltic pump and evaluated with four different vectors (2.7-11.5 kbp). Starting with 5-10 g of E. coli cell paste (wet wt.) generally satd. the membrane adsorber, resulting in plasmid DNA yields close to 10 mg. [on SciFinder(R)]
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| 35. |
- Trtic, Tatjana, et al.
(författare)
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Determination of drug-protein binding using supported liquid membrane extraction under equilibrium conditions
- 2005
-
Ingår i: Journal of Chromatography. B. - : Elsevier BV. - 1873-376X .- 1570-0232. ; 814:2, s. 375-384
-
Tidskriftsartikel (refereegranskat)abstract
- A technique for determination of drug-protein binding based on a membrane extraction technique termed "equilibrium sampling through membrane (ESTM)" is presented. It involves the establishment of an equilibrium between an aqueous buffer and either a blood plasma sample or a matched buffer, both containing the drug. Analysis of the aqueous buffer in the two cases gives the drug-protein binding. The principle bypasses some sources of systematic error found with common techniques for this measurement based on e.g. ultrafiltration, as it senses the equilibrium conditions without disturbing the sample. The technique is applied to some local anesthetic drugs as model substances and two alternative ways for the evaluation are presented. Results with these evaluation methods are compared with literature values for the drug-protein binding of these compounds. It is found that the drug-protein binding values obtained are lower than literature values, which is attributed to reduced systematic error. (C) 2004 Elsevier B.V. All rights reserved.
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| 36. |
- Trtic, Tatjana, et al.
(författare)
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Equilibrium sampling through membrane based on a single hollow fibre for determination of drug-protein binding and free drug concentration in plasma
- 2005
-
Ingår i: Journal of Chromatography. B. - : Elsevier BV. - 1873-376X .- 1570-0232. ; 826:1-2, s. 169-176
-
Tidskriftsartikel (refereegranskat)abstract
- The determination of drug-protein binding and free drug concentration in plasma applying the equilibrium sampling through membrane (ESTM) technique has been studied using supported liquid membrane extraction in a single hollow fibre without any membrane carrier. In the extraction setup, the donor phase (plasma or buffer) was placed in the vial, into which was immersed the hollow fibre with the acceptor phase situated in the lumen. This proposed technique was applied to study the drug-protein binding of five local anaesthetics and two antidepressants as model substances, and the influence of the total drug concentration on the drug-protein binding was investigated. The brief theoretical background for determination of the drug-protein binding under equilibrium conditions is described. The developed method shows a new, improved and simple procedure for determination of free drug concentration in plasma and extent of drug-protein binding. (c) 2005 Elsevier B.V. All rights reserved.
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| 37. |
- Ullah, Faiz, et al.
(författare)
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Determination of heterocyclic aromatic amines in human urine by using hollow-fibre supported liquid membrane extraction and liquid chromatography-ultraviolet detection system.
- 2008
-
Ingår i: Journal of Chromatography. B. - : Elsevier BV. - 1873-376X .- 1570-0232. ; 870:2, s. 203-208
-
Tidskriftsartikel (refereegranskat)abstract
- A hollow-fibre supported liquid membrane (HF-SLM) extraction method has been developed for determination of 11 heterocyclic aromatic amines (HCAs) in human urine samples by using high performance liquid chromatography (HPLC) equipped with an ultraviolet (UV) absorbance detector. These compounds were extracted from an alkaline urine sample (donor phase) into the organic solvent residing in the pores of a polypropylene hollow fibre and then back extracted into an acidic solution (acceptor phase) inside the lumen of the hollow fibre. After extraction, HCAs were analyzed by injecting the analyte enriched acceptor phase into the HPLC. The analyte enrichment factors ranged between 241 and 339 obtained in a 90min extraction time, and method detection limits (MDL) ranged between 0.1 and 0.5mugL(-1) with relative standard deviation (RSD) values between 3.4% and 11%. The extraction technique employed in this work is easy to use and rapid as it involves only a few minutes manipulation of each sample. It is the most economical sample preparation/preconcentration technique to our knowledge as compared to other microextraction techniques.
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| 38. |
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| 39. |
- Xu, Jianqiang, et al.
(författare)
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Assessment of 4-nitro-1,8-naphthalic anhydride reductase activity in homogenates of bakers' yeast by reversed-phase high-performance liquid chromatography
- 2007
-
Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 847:2, s. 82-87
-
Tidskriftsartikel (refereegranskat)abstract
- A simple reversed-phase high-performance liquid chromatographic (RP-HPLC) method was developed for the simultaneous determination of yield and conversion ratio of 4-nitro-1,8-naphthalic anhydride to 4-amino-1,8-naphthalic anhydride following incubation with a crude bakers’ yeast homogenate. The analytes were separated on a C18 column in gradient mode. The detection limit of 4-amino-1,8-naphthalic anhydride is 10 ng/μl when using a 10 μl sample injection volume. The nitroreductase activity in the homogenate system can be assessed during the bioconversion process. The method can be used for the simultaneous detection of 4-hydroxylamino-1,8-naphthalic anhydride, an intermediate with limited stability.
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| 40. |
- Zhang, Qi, et al.
(författare)
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GC/MS analysis of the rat urine for metabonomic research
- 2007
-
Ingår i: Journal of chromatography. B. - Amsterdam : Elsevier. - 1570-0232 .- 1873-376X. ; 854:1-2, s. 20-25
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, an optimized protocol was established and validated for the metabonomic profiling in rat urine using GC/MS. The urine samples were extracted by methanol after treatment with urease to remove excessive urea, then the resulted supernatant was dried, methoximated, trimethylsilylated, and analyzed by GC/MS. Forty-nine endogenous metabolites were separated and identified in GC/MS chromatogram, of which 26 identified compounds were selected for quantitative analysis to evaluate the linearity, precision, and sensitivity of the method. It showed good linearity between mass spectrometry responses and relative concentrations of the 26 endogenous compounds over the range from 0.063 to 1.000(v/v, urine/urine+ water) and satisfactory reproducibility with intra-day and inter-days precision values all below 15%. The metabonomic profiling method based on GC/MS was successfully applied to urine samples from hyperlipidemia model rats. Obviously, separated clustering of model rats and the control rats were shown by principal components analysis (PCA); time-dependent metabonomic modification was detected as well. It was suggested that metabonomic profiling based on GC/MS be a robust method for urine samples.
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| 41. |
- Zhao, Guohua, et al.
(författare)
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Determination of short-chain fatty acids in serum by hollow fiber supported liquid membrane extraction coupled with gas chromatography
- 2007
-
Ingår i: Journal of Chromatography. B. - : Elsevier BV. - 1873-376X .- 1570-0232. ; 846:1-2, s. 202-208
-
Tidskriftsartikel (refereegranskat)abstract
- A method based on hollow fiber supported liquid membrane extraction coupled with a gas chromatograph equipped with flame ionization detector (GC-FID) was developed for the determination of six short-chain fatty acids including acetic acid, propionic acid, i-butyric acid, n-butyric acid, i-valeric acid and n-valeric acid in serum. Hollow fiber supported liquid membrane extraction was employed for preconcentration and clean-up of the samples. The fatty acids were extracted from the acidic donor (diluted serum) into a liquid membrane formed in the wall of the hollow fiber with 10% tri-n-octylphoshphine oxide (TOPO) in di-n-hexyl ether, and then extracted back into a basic acceptor solution filled in the lumen of the hollow fiber. After being acidified with HCl, the acceptor was directly analyzed by GC-FID. The acceptor concentration, donor pH, membrane liquid and extracting time were optimized giving an enrichment factor up to 155 times. The good linearity (r2 > 0.980), reasonable recovery (87.2-121%), and satisfactory intra-assay (8.2-11.5%) and inter-assay (6.1-11.6%) precision illustrated the good performance of the present method. Limits of detection (LOD) ranged from 0.04 to 0.24 μM and limits of quantification (LOQ) varied from 0.13 to 0.80 μM.
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| 42. |
- Zhou, Weibin, et al.
(författare)
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Molecular characterization of recombinant Hepatitis B surface antigen from Chinese hamster ovary and Hansenula polymorpha cells by high-performance size exclusion chromatography and multi-angle laser light scattering
- 2006
-
Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 838:2, s. 71-77
-
Tidskriftsartikel (refereegranskat)abstract
- The molecular weight and size of recombinant Hepatitis B surface antigen (HBsAg) derived from Chinese hamster ovary (CHO) and the Hansenula polymorph have been characterized by high-performance size exclusion chromatography with multi-angle laser light scattering (HPSEC-MALLS). The average molecular weight of CHO-derived HBsAg particle (CHO-rHBsAg) (4921 kDa) was higher than that of H. polymorpha yeast strain (Hans-rHBsAg) (3010 kDa). The size of CHO-rHBsAg (22.1 nm) is nearly the same as that of native HBsAg compared to 18.1 nm for Hans-rHBsAg. The average monomer numbers were found to be 155 for CHO-rHBsAg and 86 for Hans-rHBsAg, respectively. The data obtained support the assumption that the higher immunogenicity of CHO-derived HBsAg is related to its more favorable macromolecular assembly structure.
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| 43. |
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| 44. |
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| 45. |
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| 46. |
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| 47. |
- Idborg, Helena, et al.
(författare)
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Metabolic fingerprinting of rat urine by LC/MS. : Part 2. Data pretreatment methods for handling of complex data
- 2005
-
Ingår i: Journal of Chromatography B. - : Elsevier BV. - 1387-2273 .- 1878-5603 .- 1570-0232. ; 828:1-2, s. 14-20
-
Tidskriftsartikel (refereegranskat)abstract
- Metabolic fingerprinting of biofluids like urine is a useful technique for detecting differences between individuals. With this approach, it might be possible to classify samples according to their biological relevance. In Part I of this work a method for the comprehensive screening of metabolites was described [H. Idborg, L. Zamani, P-O. Edlund, I. Schuppe-Koistinen, S.P. Jacobsson, Part 1, J. Chromatogr. B 828 (2005) 9], using two different liquid chromatography (LC) column set-ups and detection by electrospray ionization mass spectrometry (ESI-MS). Data pretreatment of the resulting data described in [H. Idborg, L. Zamani, P-O. Edlund, 1. Schuppe-Koistinen, S.P. Jacobsson, Part 1, J. Chromatogr. B 828 (2005) 9] is needed to reduce the complexity of the data and to obtain useful metabolic fingerprints. Three different approaches, i.e., reduced dimensionality (RD), MarkerLynx (TM), and MS Resolver (TM), were compared for the extraction of information. The pretreated data were then subjected to multivariate data analysis by partial least squares discriminant analysis (PLS-DA) for classification. By combining two different chromatographic procedures and data analysis, the detection of metabolites was enhanced as well as the finding of metabolic fingerprints that govern classification. Additional potential biomarkers or xenobiotic metabolites were detected in the fraction containing highly polar compounds that are normally discarded when using reversed-phase liquid chromatography.
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| 48. |
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| 49. |
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| 50. |
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