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  • 1.
    Abrahamsson, Maria
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Accelerator mass spectrometry group. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Wolpher, Henriette
    Johansson, Olof
    Larsson, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Kritikos, Mikael
    Eriksson, Lars
    Norrby, Per-Ola
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Sun, Licheng
    Åkermark, Björn
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    A New Strategy for the Improvement of Photophysical Properties in Ruthenium(II) Polypyridyl Complexes: Synthesis and Photophysical and Electrochemical Characterization of Six Mononuclear Ruthenium(II) Bisterpyridine-Type Complexes2005In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 44, no 9, p. 3215-3225Article in journal (Refereed)
  • 2.
    Amirkhani, Ardeshir
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Heldin, Eva
    Markides, Karin E.
    Bergquist, Jonas
    Quantitation of tryptophan, kynurenine and kynurenic acid in human plasma by capillary liquid chromatography - electrospray2002In: Journal of Chromatography B, Vol. 780, no 2, p. 381-387Article in journal (Refereed)
  • 3.
    Amirkhani, Ardeshir
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Rajda, Cecilia
    Arvidsson, Björn
    Bencsik, Krisztina
    Boda, Krisztina
    Seres, Erika
    Markides, Karin E.
    Vecsei, Laszlo
    Bergquist, Jonas
    Beta-interferon effects the tryptophan metabolism in the plasma of multiple sclerosis patientsManuscript (Other academic)
  • 4.
    Amirkhani, Ardeshir
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Rajda, Cecilia
    Arvidsson, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Bencsik, Krisztina
    Boda, Krisztina
    Seres, Erika
    Markides, Karin E.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Vecsei, Laszlo
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Interferon-beta affects the tryptophan metabolism in multiple sclerosis patients2005In: European Journal of Neurology, ISSN 1351-5101, E-ISSN 1468-1331, Vol. 12, no 8, p. 625-631Article in journal (Refereed)
    Abstract [en]

    Tryptophan and its metabolites are of great interest in understanding the pathogenesis of multiple sclerosis (MS). The total levels of tryptophan and its metabolites, kynurenine and kynurenic acid were determined in plasma by capillary liquid chromatography electrospray ionisation tandem mass spectrometry. This is the first report of the plasma levels of these analytes in healthy controls and relapsing-remitting MS patients receiving long-term and acute interferon-beta (IFN-beta) treatment. Twenty-four hours post-administration increased kynurenine levels (first IFN MS versus healthy, P = 0.042) and kynurenine/tryptophan ratio (K/T; first IFN MS versus healthy, P =0.027; first IFN MS versus long-term IFN MS, P = 0.036) were found. The long-term IFN MS group had higher K/T ratios at 4 and 12 h post-administration (P = 0.015 and 0.009, respectively). The increase of K/T ratio in the first IFN MS group indicate an induction of the enzyme indolamine-2,3-dioxygenase (IDO), as reported earlier in experimental allergic encephalomyelitis. As IDO is participating in both inflammatory and neurodegenerative processes, further knowledge of its involvement in the pathogenesis of MS is of great importance.

  • 5.
    Amirkhani, Ardeshir
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Wetterhall, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Nilsson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Danielsson, Rolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Comparison between different sheathless electrospray emitter configurations regarding the performance of nanoscale liquid chromatography time-of-flight mass spectrometry analysis2004In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1033, no 2, p. 257-266Article in journal (Refereed)
    Abstract [en]

    Four different sheathless electrospray ionization (ESI) configurations were investigated for a nano liquid chromatography (LC) system. The studied configurations were: a column with an integrated emitter, with the ESI potential applied before or after the column, and a column with separate emitter, with the ESI voltage applied at a union before the emitter or at the emitter tip. The results indicates that the efficiency of the LC system is rather independent of the configuration when using 95 μm i.d. columns, acetic mobile phase and standard peptides as a sample. Introduction of post column dead volume seems not to be a critical issue at least with flow rates down to 600 nl/min.

  • 6. Bazoti, Fotini N.
    et al.
    Tsarbopoulos, Anthony
    Markides, Karin E.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Bergquist, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Study of the non-covalent interaction between amyloid-b-peptide and melatonin using electrospray ionization mass spectrometry2005In: Journal of Mass Spectrometry, no 40, p. 182-192Article in journal (Refereed)
    Abstract [en]

    Oxidative stress and unregulated immune response are believed to play a key role in the processes inherent to Alzheimer's disease (AD). The fact that free radicals can result in neurodegeneration suggests that actions against reactive oxygen species may be beneficial in treating and preventing AD. In the light of the suggested link between oxidative stress and AD, it is proposed that antioxidants and, even more, endogenous antioxidants may offer a therapeutic regime for protection against the risk of this disease. For this reason, the formation of non-covalent complexes between amyloid-b-peptide (Ab) or its oxidized forms and melatonin was studied by quadrupole and Fourier transform ion cyclotron resonance electrospray ionization mass spectrometry. The stability of the non-covalent complex was examined under several experimental conditions, such as orifice voltage, pH, presence of organic modifier, concentration and time. Two different digestion protocols combined with mass spectrometric analysis of the resulting peptide fragments were employed in order to locate the binding site of melatonin in Ab.

  • 7.
    Bhaskaran, Nimesh
    et al.
    Karolinska University Hospital.
    Iwahana, Hiroyuki
    Karolinska University Hospital.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Hellman, Ulf
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Souchelnytskyi, Serhiy
    Karolinska University Hospital.
    Novel post-translational modifications of Smad2 identified by mass spectrometry2008In: Central European Journal of Biology, ISSN 1895-104X, E-ISSN 1644-3632, Vol. 3, no 4, p. 359-370Article in journal (Refereed)
    Abstract [en]

    Smad2 is a crucial component of transforming growth factor-b (TGFb) signaling, and is involved in the regulation of cell proliferation,death and differentiation. Phosphorylation, ubiquitylation and acetylation of Smad2 have been found to regulate its activity. We usedmass spectrometry to search for novel post-translational modifications (PTMs) of Smad2. Peptide mass fingerprinting (PMF) indicatedthat Smad2 can be acetylated, methylated, citrullinated, phosphorylated and palmitoylated. Sequencing of selected peptides validatedmethylation at Gly122 and hydroxylation at Trp18 of Smad2. We also observed a novel, so far unidentified modification at Tyr128 andTyr151. Our observations open for further exploration of biological importance of the detected PTMs.

  • 8.
    Bäckström, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Allard, Erik
    Danielsson, Rolf
    Sjöberg, Per
    Bergquist, Jonas
    Comparing CE-MS fingerprints of urine samples, obtained after intake of coffee, tea or waterManuscript (Other academic)
  • 9.
    Dahlin, Andreas P.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Bergström, Sara K.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Andrén, Per E.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences, MMS, Medical Mass Spectrometry.
    Markides, Karin E.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Poly(dimethylsiloxane)-Based Microchip for Two-Dimensional Solid-Phase Extraction-Capillary Electrophoresis with an Integrated Electrospray Emitter Tip2005In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 77, no 16, p. 5356-5363Article in journal (Refereed)
    Abstract [en]

    A microchip in poly(dimethylsiloxane) (PDMS) for in-line solid-phase extraction-capillary electrophoresis-electrospray ionization-time-of-flight mass spectrometry (SPE-CE-ESI-TOF-MS) has been developed and evaluated. The chip was fabricated in a novel one-step procedure where mixed PDMS was cast over steel wires in a mold. The removed wires defined 50-um cylindrical channels. Fused-silica capillaries were inserted into the structure in a tight fit connection. The inner walls of the inserted fused-silica capillaries and the PDMS microchip channels were modified with a positively charged polymer, PolyE-323. The chip was fabricated in a two-level cross design. The channel at the lower level was packed with 5-um hyper-cross-linked polystyrene beads acting as a SPE medium used for desalting. The upper level channel acted as a CE channel and ended in an integrated emitter tip coated with conducting graphite powder to facilitate the electrical contact for sheathless ESI. An overpressure continuously provided fresh CE electrolyte independently of the flows in the different levels. Further studies were carried out in order to investigate the electrophoretic and flow rate properties of the chip. Finally, six-peptide mixtures, in different concentrations, dissolved in physiological salt solution was injected, desalted, separated, and sprayed into the mass spectrometer for analysis with a limit of detection in femtomole levels.

  • 10. Dobrovolsky, Vasily N.
    et al.
    Bowyer, John F.
    Pabarcus, Michael K.
    Heflich, Robert H.
    Williams, Lee D.
    Doerge, Daniel R.
    Arvidsson, Björn
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Bergquist, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Casida, John E.
    Effect of arylformamidase (kynurenine formamidase) gene inactivation in mice on enzymatic activity, kynurenine pathway metabolites and phenotype2005In: Biochimica et Biophysica Acta, no 1724, p. 163-172Article in journal (Refereed)
    Abstract [en]

    The gene coding for arylformamidase (Afmid, also known as kynurenine formamidase) was inactivated in mice through the removal of a shared bidirectional promoter region regulating expression of the Afmid and thymidine kinase (Tk) genes. Afmid/Tk-deficient mice are known to develop sclerosis of glomeruli and to have an abnormal immune system. Afmid-catalyzed hydrolysis of N-formyl-kynurenine is a key step in tryptophan metabolism and biosynthesis of kynurenine-derived products including kynurenic acid, quinolinic acid, nicotinamide, NAD, and NADP. A disruption of these pathways is implicated in neurotoxicity and immunotoxicity. In wild-type (WT) mice, Afmid-specific activity (as measured by formyl-kynurenine hydrolysis) was 2-fold higher in the liver than in the kidney. Formyl-kynurenine hydrolysis was reduced by ~50% in mice heterozygous (HZ) for Afmid/Tk and almost completely eliminated in Afmid/Tk knockout (KO) mice. However, there was 13% residual formyl-kynurenine hydrolysis in the kidney of KO mice, suggesting the existence of a formamidase other than Afmid. Liver and kidney levels of nicotinamide plus NAD/NADP remained the same in WT, HZ and KO mice. Plasma concentrations of formyl-kynurenine, kynurenine, and kynurenic acid were elevated in KO mice (but not HZ mice) relative to WT mice, further suggesting that there must be enzymes other than Afmid (possibly in the kidney) capable of metabolizing formyl-kynurenine into kynurenine. Gradual kidney deterioration and subsequent failure in KO mice is consisten with high levels of tissue-specific Afmid expression in the kidney of WT but not KO mice. On this basis, the most significant function of the kynurenine pathway and Afmid in mice may be in eliminating toxic metabolites and to a lesser extent in providing intermediates for other processes.

  • 11.
    Ericsson, D.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Ekström, S.Nilsson, J.Bergquist, JonasUppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.Marko-Varga, G.Laurell, T.
    Dispenser-aided nanodigestion for rapid protein identification in MALDI-TOF nanovial arrays2001Conference proceedings (editor) (Other academic)
  • 12. Hagman, Charlotte
    et al.
    Ramström, Margareta
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Håkansson, Per
    Bergquist, Jonas
    Quantitative Analysis of Tryptic Protein Mixtures Using Electrospray Ionization Fourier Transform Ion Cyclotron Mass Spectrometry2004In: Journal of Proteome Research, ISSN 1535-3893, Vol. 3, no 3, p. 587-594Article in journal (Refereed)
  • 13.
    Hagman, Charlotte
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Ramström, Margareta
    Chemistry, Department of Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. analytisk kemi.
    Håkansson, Per
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Bergquist, Jonas
    Chemistry, Department of Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Analytisk kemi.
    Quantitative analysis of tryptic protein mixtures using electrospray ionization fourier transform ion cyclotron resonance mass spectrometry2004In: Journal of proteome research, no 3, p. 587-594Article in journal (Refereed)
  • 14.
    Isaac, Giorgis
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Bylund, Dan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Månsson, Jan-Eric
    Institute of Clinical Neuroscience, Sahlgrenska University Hospital, Göteborg University, Sweden.
    Markides, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Analysis of phosphatidylcholine and sphingomyelin molecular species from brain extracts using capillary liquid chromatography electrospray ionization mass spectrometry2003In: Journal of Neuroscience Methods, ISSN 0165-0270, E-ISSN 1872-678X, Vol. 128, no 1-2, p. 111-119Article in journal (Refereed)
    Abstract [en]

    One feature of complex lipids is that many subtypes of these molecules exist as a diverse mixture in a biological sample. Qualitative and quantitative analysis of these closely related molecules require sensitive and specific analytical methods to detect intact phospholipids (PL) and sphingomyelin (SM) species and to differentiate between them. Conventional analytical methods require laborious procedures including separation by column, argentation thin-layer chromatography or liquid chromatography (LC) after pre- or post-column derivatization. In the present work, a method based on reversed phase capillary LC coupled on-line to electrospray ionization mass spectrometry (LC/ESI/MS) has been developed to gather tools for lipidomic studies, i.e. the profiling of complex mixtures of lipids in small amounts of various cells and tissues. The LC/MS system used consisted of an LC pump in an isocratic elution, a reversed phase capillary column and a single quadrupole mass spectrometer operated in the positive ion mode. A successful separation of phosphatidylcholine (PC) and SM molecular species was obtained with a minimum detectable quantity (MDQ) in the low fmol range injected on column. The method was applied to human brain extracts. Furthermore, the extraction efficiencies of the traditional Folch method and pressurized fluid extraction (PFE) were compared using the human brain. It was found that the intensity of the PC and SM molecular species extracted by PFE is two times that of Folch.

  • 15.
    Isaac, Giorgis
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Bylund, Dan
    Månsson, Jan-Eric
    Markides, Karin E.
    Bergquist, Jonas
    Analysis of Phosphatidylcholine and Sphingomyelin Molecular Species From Brain Extracts Using Capillary Liquid Chromatography Electrospray Ionization Mass Spectrometry2003In: Journal of Neuroscience Methods, ISSN 0165-0270, Vol. 128, no 1-2, p. 111-119Article in journal (Refereed)
  • 16.
    Isaac, Giorgis
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Fredriksson, Anders
    Danielsson, Rolf
    Eriksson, Per
    Bergquist, Jonas
    Brain Lipid Composition in Postnatal Iron-Induced Motor Behavior Alterations Following Chronic Neuroleptic Administration in MiceIn: Neuroscience LettersArticle in journal (Refereed)
  • 17.
    Isaac, Giorgis
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Månsson, Jan-Eric
    Gieselmann, Volkmar
    Hansson, Elisabeth
    Pernber, Zarah
    Bergquist, Jonas
    Characterization of Brain Sulfatide Molecular Species in Arylsulfatase A Deficient Mice Using Electrospray Ionization Tandem Mass SpectrometryManuscript (Other academic)
  • 18.
    Johannesson, Nina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Wetterhall, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Markides, Karin E.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Monomer surface modifications for rapid peptide analysis by capillary electrphoresis and capillary electrochromatography coupled to electrospray ionization mass spectrometry2004In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 25, no 6, p. 809-816Article in journal (Refereed)
    Abstract [en]

    In this study, positively charged alkylaminosilyl monomers were used to modify the inner surface of fused silica capillaries, which subsequently were employed in capillary electrophoresis (CE) and capillary electrochromatography (CEC). The obtained surfaces yield a reversed electroosmotic flow (EOF) and have varying carbon chain lengths, that interact with the analytes and give chromatographic retention. The coating procedure is very simple and fast. The performance of the modified capillaries was evaluated regarding pH influence on EOF and chromatographic interactions. The experiments were conducted with UV and mass spectrometry (MS) and applied to the separation of various neuropeptides. The derivatized surfaces showed a linear (R2 ∼0.99) pH dependence with isoelectric points (pI) at 8.6–8.8. Rapid separations of peptide standards and a protein digest with efficiencies as high as 5×105 plates/m were performed.

  • 19. Johansson, Olof
    et al.
    Wolpher, Henriette
    Borgström, Magnus
    Hammarström, Leif
    Bergquist, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Sun, Licheng
    Åkermark, Björn
    Intramolecular charge separation in a hydrogen bonded tyrosine-ruthenium(II)-naphthalane diimide triad2004In: Chem. Commun., p. 194-195Article in journal (Refereed)
    Abstract [en]

    Long-lived charge-separated states in the ns to us range were observed upon laser flash excitation of a donor-chromophore-acceptor triad based on tris(bipyridine) ruthenium(II) as photosensitizer, naphthalene diimide as acceptor, and a hydrogen bonded phenol as donor.

  • 20. Johansson, Olof
    et al.
    Wolpher, Henriette
    Borgström, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Hammarström, L.eif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Sun, Licheng
    Åkermark, Björn
    Intramolecular charge separation in a hydrogen bonded tyrosine-ruthenium(II)-naphthalene diimide triad2004In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 2, p. 194-195Article in journal (Refereed)
    Abstract [en]

    Long-lived charge-separated states in the ns to [micro sign]s range were observed upon laser flash excitation of a donor-chromophore-acceptor triad based on tris(bipyridine) ruthenium(ii) as photo-sensitizer, naphthalene diimide as acceptor, and a hydrogen bonded phenol as donor.

  • 21.
    Kushnir, Mark M
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Naessen, Tord
    Kirilovas, Dmitrijus
    Chaika, Andrey
    Nosenko, Jelena
    Mogilevkina, Iryna
    Rockwood, Alan L
    Carlstrom, Kjell
    Bergquist, Jonas
    Steroid profiles in ovarian follicular fluid samples using high sensitivity tandem mass spectrometry methodsIn: Article in journal (Refereed)
  • 22.
    Kushnir, Mark M
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Rockwood, Alan L
    Bergquist, Jonas
    Varshavsky, Marina
    Roberts, William L
    Yue, Bingfang
    Bunker, Ashely M
    Meikle, A Wayne
    High sensitivity tandem mass spectrometry assay for serum estrone and estradiol2008In: American Journal of Clinical Pathology, ISSN 0002-9173, E-ISSN 1943-7722, Vol. 129, no 4, p. 530-539Article in journal (Refereed)
    Abstract [en]

    High-sensitivity measurement of serum estrogens is important in adult and pediatric endocrinology and oncology. We developed a high-sensitivity liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for simultaneous measurement of estrone (E-1) and estradiol (E-2). Aliquots of 200 mu L of serum were spiked with internal standard, extracted, derivatized with dansyl chloride, and analyzed by LC-MS/MS using 2-dimensional chromatographic separation. Total imprecision for the method was less than 11%; the limit of quantitation was 1 pg/mL. Reference intervals were established with samples from more than 900 healthy postmenopausal women, men, girls, and boys. Concentrations of estrogens in children reached adult levels by Tanner stage 3. In men and postmenopausal women, the median concentrations of total estrogens (E-1 + E-2) were 39 and 22 pg/mL, and the median E-2/E-1 ratios were 0.98 and 0.55, respectively. The method requires a small sample volume and has adequatesensitivity and specificity for analyzing estrogens in samples from postmenopausal women, men, and children.

  • 23.
    Liljegren, Gustav
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Dahlin, Andreas P.
    Zettersten, Camilla
    Bergquist, Jonas
    Nyholm, Leif
    On-line coupling of a microelectrode array equipped poly(dimethylsiloxane) microchip with an integrated graphite electrospray emitter to electrospray ionisation mass spectrometryManuscript (Other academic)
  • 24. Liljegren, Gustav
    et al.
    Dahlin, Andreas P.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Zettersten, Camilla
    Bergquist, Jonas
    Nyholm, Leif
    On-line coupling of a microelectrode array equipped poly(dimethylsiloxane) microchip with an integrated graphite electrospray tip to electrospray mass spectrometryIn: Article in journal (Refereed)
  • 25.
    Liljegren, Gustav
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Dahlin, Andreas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Zettersten, Camilla
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Bergquist, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Nyholm, Leif
    Department of Materials Chemistry, Inorganic Chemistry. Oorganisk kemi.
    On-line coupling of a microelectrode array equipped poly(dimethylsiloxane) microchip with an integrated graphite electrospray emitter for electrospray ionisation mass spectrometry2005In: Lab on a Chip, no 5, p. 1008-1016Article in journal (Refereed)
    Abstract [en]

    A novel method for the manufacturing of microchips for on-chip combinations of electrochemistry (EC) and sheathless electrospray ionisation mass spectrometry (ESI-MS) is described. The technique, which does not require access to clean-room facilities, is based on the incorporation of an array of gold microcoil electrodes into a poly(dimethylsiloxane) (PDMS) microflow channel equipped with an integrated graphite based sheathless ESI emitter. Electrochemical measurements, which were employed to determine the electroactive area of the electrodes and to test the microchips, show that the manufacturing process was reproducible and that the important interelectrode distance in the electrochemical cell could to be adequately controlled. The EC-ESI-MS device was evaluated based on the ESI-MS detection of the oxidation products of dopamine. The results demonstrate that the present on-chip approach enables full potentiostatic control of the electrochemical cell and the attainment of very short transfer times between the electrochemical cell and the electrospray emitter. The transfer times were 0.6 and 1.2 s for flow rates of 1.0 and 0.5 uL min-1, respectively, while the electrochemical conversion efficiency of the electrochemical cell was found to be 30% at a flow rate of 0.5 uL min-1. To decouple the electrochemical cell from the ESI-MS high voltage and to increase the user-friendliness, the on-line electrochemistry-ESI-MS experiments were performed using a wireless Bluetooth battery-powered instrument with the chip floating at the potential induced by the ESI high voltage. The described on-chip EC-ESI-MS device can be used for fundamental electrochemical investigations as well as for applications based on the use of electrochemically controlled sample pretreatment, preconcentration and ionisation steps prior to ESI-MS.

  • 26. Nilsson, Stefan
    et al.
    Ramström, Margareta
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Palmblad, Magnus
    Axelsson, Ove
    Bergquist, Jonas
    An Explorative Study of the Protein Composition of Amniotic Fluid by Liquid Chromatography Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry2004In: Journal of Proteome Research, ISSN 1535-3893, Vol. 3, no 4, p. 884-889Article in journal (Refereed)
  • 27.
    Nilsson, Stefan
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics. Analytisk kemi.
    Ramström, Margareta
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics. Analytisk kemi.
    Palmblad, Magnus
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Axelsson, Ove
    Bergquist, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics. Analytisk kemi.
    Explorative Study of the Protein Composition of Amniotic Fluid by Liquid Chromatography Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry2004In: Journal of Proteome Research, no 3, p. 884-889Article in journal (Refereed)
    Abstract [en]

    To explore the suitability of FTICR mass spectrometry for the analysis of the protein composition of amniotic fluid (AF), an AF sample from 15 weeks gestation from a healthy 36-year-old woman was tryptically digested, with or without prior serum albumin removal. The tryptic peptides were separated by gradient capillary liquid chromatography (LC) followed by electrospray ionization (ESI) and mass spectrometric detection with a 9.4 T Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR). The obtained data underwent computer-aided mathematical and statistical evaluation to extract significant tryptic peptide patterns from human proteins. Forty-three proteins were putatively identified; among them were known protein constituents of amniotic fluid, but also many that not have been detected before. The removal of serum albumin prior to tryptic digestion reduced ion suppression from abundant HSA fragments. The protein analysis of amniotic fluid by albumin removal, tryptic digestion and LC/FT-ICR-MS analysis was found to be a straightforward technique.

  • 28.
    Nilsson, Stefan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Wetterhall, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Markides, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    A simple and robust conductive graphite coating for sheathless electrospray emitters used in capillary electrophoresis/mass spectrometry2001In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 15, no 21, p. 1997-2000Article in journal (Refereed)
    Abstract [en]

    A graphite-polyimide mixture was used as a conductive coating for sheathless electrospray emitters. The coating procedure described is simple and inexpensive compared to previously described methods. An investigation of the stability of the conductive coating carried out by electrochemical methods revealed good performances during oxidative stress. In addition, no decrease in emitter performance was seen during continuous electrospray in the positive electrospray mode for two weeks. Fast capillary electrophoresis with attomole sensitivity demonstrated the excellent performance of the described sheathless interface when used in conjunction with an orthogonal time-of-flight mass spectrometer. The overall simplicity, stability and low cost of this type of sheathless emitter make the described approach highly suitable for any on-column coupling of low flow rate separation techniques to a mass spectrometer.

  • 29. Ott, Sascha
    et al.
    Borgström, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Kritikos, Mikael
    Lomoth, Reiner
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Åkermark, Björn
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Sun, Licheng
    Model of the iron hydrogenase active site covalently linked to a ruthenium photosensitizer: Synthesis and photophysical properties2004In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 43, no 15, p. 4683-4692Article in journal (Refereed)
    Abstract [en]

    A model of the iron hydrogenase active site with the structure [(mu-ADT)Fe2(CO)6] (ADT = azadithiolate (S-CH2-NR-CH2-S), (2: R = 4-bromophenyl, 3: R = 4-iodophenyl)) has been assembled and covalently linked to a [Ru(terpy)2]2+ photosensitizer. This trinuclear complex 1 represents one synthetic step toward the realization of our concept of light-driven proton reduction. A rigid phenylacetylene tether has been incorporated as the linking unit in 1 in order to prolong the lifetime of the otherwise short-lived [Ru(terpy)2]2+ excited state. The success of this strategy is demonstrated by comparison of the photophysical properties of 1 and of two related ruthenium complexes bearing acetylenic terpyridine ligands, with those of [Ru(terpy)2]2+. IR and electrochemical studies reveal that the nitrogen heteroatom of the ADT bridge has a marked influence on the electronic properties of the [Fe2(CO)6] core. Using the Rehm-Weller equation, the driving force for an electron transfer from the photoexcited *[Ru(terpy)2]2+ to the diiron site in 1 was calculated to be uphill by 0.59 eV. During the construction of the trinuclear complex 1, n-propylamine has been identified as a decarbonylation agent on the [(mu-ADT)Fe2(CO)6] portion of the supermolecule. Following this procedure, the first azadithiolate-bridged dinuclear iron complex coordinated by a phosphine ligand [(mu-ADT)Fe2(CO)5PPh3] (4, R = 4-bromophenyl) was synthesized.

  • 30.
    Palmblad, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Ramström, Margareta
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Markides, Karin E
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Håkansson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Prediction of chromatographic retention and protein identification in liquid chromatography/mass spectrometry2002In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 74, no 22, p. 5826-5830Article in journal (Refereed)
    Abstract [en]

    Liquid chromatography coupled on- or off-line with mass spectrometry is rapidly advancing as a tool in proteomics capable of dealing with the inherent complexity in biology and complementing conventional approaches based on two-dimensional gel electrophoresis. Proteins can be identified by proteolytic digestion and peptide mass fingerprinting or by searching databases using short-sequence tags generated by tandem mass spectrometry. This paper shows that information on the chromatographic behavior of peptides can assist protein identification by peptide mass fingerprinting in liquid chromatography/mass spectrometry. This additional information is significant and already available at no extra experimental cost.

  • 31.
    Palmblad, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Tsybin, Youri O
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Ramström, Margareta
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Håkansson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Liquid Chromatography and Electron Capture Dissociation in Fourier Transform Ion Cyclotron Resonance Mass Spectrometry2002In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 16, no 10, p. 988-992Article in journal (Refereed)
    Abstract [en]

    Liquid separation methods in combination with electrospray mass spectrometry as well as the recently introduced fragmentation method electron capture dissociation (ECD) have become powerful tools in proteomics research. This paper presents the results of the first successful attempts to combine liquid chromatography (LC) and Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) with ECD in the analysis of a mixture of standard peptides and of a bovine serum albumin tryptic digest. A novel electron injection system provided conditions for ECD sufficient to yield extensive sequence information for the most abundant peptides in the mixtures on the time-scale of the chromatographic separation. The results suggest that LC/ECD-FTICRMS can be employed in the characterization of peptides in enzymatic digests of proteins or protein mixtures and identify and localize posttranslational modifications.

  • 32.
    Palmblad, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Westlind-Danielsson, Anita
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Oxidation of Methionine-35 Attenuates Formation of Amyloid β-Peptide 1-40 Oligomers2002In: Journal of chemical biology, ISSN 1864-6158, E-ISSN 1864-6166, Vol. 277, p. 19506-19510Article in journal (Refereed)
    Abstract [en]

    Amyloid plaques formed by aggregation of the amyloid β-peptide (Aβ) are an intrinsic component of Alzheimer disease pathogenesis. It has been suggested that oxidation of methionine 35 in Aβ has implications for Alzheimer disease, and it has been shown that oxidation of Met-35 significantly inhibits aggregation in vitro. In this study, the aggregational properties of Aβ-(1–40) before and after Met-35 oxidation were investigated using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. The results show that Aβ-(1–40)Met-35(O) trimer and tetramer formation is significantly attenuated as compared with Aβ-(1–40). This suggests that oxidation of Met-35 inhibits a conformational switch in Aβ-(1–40) necessary for trimer but not dimer formation. Random incorporation of Aβ-(1–40) and Aβ-(1–40)Met-35(O) in homo- and heterooligomers could also be observed. This is the first report of an early rate-limiting step in Aβ-(1–40) aggregation. Slowing of the fibrillization process at this early step is likely to support prolonged solubility and clearance of Aβ from brain and may reduce disease progression.

  • 33.
    Palmblad, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Wetterhall, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Markides, Karin E
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Håkansson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Analysis of Enzymatically Digested Proteins and Protein Mixtures using a 9.4 Tesla Fourier Transform Ion Cyclotron Resonance Mass Spectrometer2000In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 14, no 12, p. 1029-1034Article in journal (Refereed)
    Abstract [en]

    A commercially available 9.4 Tesla Fourier transform ion cyclotron resonance (FTICR) mass spectrometer was applied in the analysis of tryptic digests of protein mixtures without any separation. First, the method was demonstrated on a mixture of tryptic digests of equine cytochrome c, equine myoglobin and bovine serum albumin. The same method was then applied to human plasma from a healthy blood donor. Computer programs were employed to simplify analysis of the complex spectra. The 2745 peaks in the human plasma electrospray ionization FTICR spectrum could be reduced to 1165 isotopic clusters and 669 unique masses. Out of these, 82 masses matched tryptic fragments of serum albumin with mass measurement errors less than 10 ppm, covering 93% of the sequence. Another 16 masses were assigned to tryptic fragments of transferrin, covering 41% of the sequence on the 10 ppm mass measurement error level (14 within 2 ppm). The mass measurement errors were approximately normal distributed with a standard deviation of 1.7 ppm. This demonstrates the feasibility of combining the ultra-high mass resolving power and accuracy of FTICR mass spectrometry with automated computer analysis for investigating complex biological matrices.

  • 34.
    Pettersson, Andreas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Amirkhani, Ardeshir
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Arvidsson, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Markides, Karin E.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    A feasibility study of solid supported enhanced microdialysis2004In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 76, no 6, p. 1678-1682Article in journal (Refereed)
    Abstract [en]

    For the first time, a solid supported enhanced microdialysis methodology for analysis of neuropeptides is described. The microdialysis samples were, in this study, subsequently collected in fractions, dissolved from the solid particles, dried, and resolved in a formic acid buffer in order to make them suitable for capillary liquid chromatography-mass spectrometry. Different microdialysis flow profiles were evaluated where air-gapped continuous flow was considered most suitable for the solid supported microdialysis mode. Six endogenous neuropeptides were initially used to investigate the feasibility of this enhanced microdialysis methodology. The improved relative recovery obtained from the solid supported enhanced microdialysis was varying from no effect to 10 times higher as compared to ordinary microdialysis. The most efficient enrichment was obtained for luteinizing hormone releasing hormone, which was the largest but also the most hydrophilic of the peptides. In contrast, no significant difference in recovery was observed for Leu-enkephalin being the smallest and the most hydrophobic peptide tested. These results indicate an increased flux and selective uptake of hydrophilic peptides across the membrane and enrichment on the particles in solid supported microdialysis.

  • 35.
    Pettersson Dahlin, Andreas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Wetterhall, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Liljegren, Gustav
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Bergström, Sara K.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Andrén, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Materials Chemistry.
    Markides, Karin E
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Capillary electrophoresis coupled to mass spectrometry from a polymer modified poly(dimethylsiloxane) microchip with an integrated graphite electrospray tip2005In: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 130, no 2, p. 193-199Article in journal (Refereed)
    Abstract [en]

    Hybrid capillary-poly(dimethysiloxane) (PDMS) microchips with integrated electrospray ionization (ESI) tips were directly fabricated by casting PDMS in a mould. The shapes of the emitter tips were drilled into the mould, which produced highly reproducible three-dimensional tips. Due to the fabrication method of the microfluidic devices, no sealing was necessary and it was possible to produce a perfect channel modified by PolyE-323, an aliphatic polyamine coating agent. A variety of different coating procedures were also evaluated for the outside of the emitter tip. Dusting graphite on a thin unpolymerised PDMS layer followed by polymerisation was proven to be the most suitable procedure. The emitter tips showed excellent electrochemical properties and durabilities. The coating of the emitter was eventually passivated, but not lost, and could be regenerated by electrochemical means. The excellent electrochemical stability was further confirmed in long term electrospray experiments, in which the emitter sprayed continuously for more than 180 h. The PolyE-323 was found suitable for systems that integrate rigid fused silica and soft PDMS technology, since it simply could be applied successfully to both materials. The spray stability was confirmed from the recording of a total ion chromatogram in which the electrospray current exhibited a relative standard deviation of 3.9% for a 30 min run. CE-ESI-MS separations of peptides were carried out within 2 min using the hybrid PDMS chip resulting in similar efficiencies as for fused silica capillaries of the same length and thus with no measurable band broadening effects, originating from the PDMS emitter.

  • 36. Rajda, Cecilia
    et al.
    Dibó, György
    Vécsei, Laszló
    Bergquist, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Increased Dopamine Content in Lymphocytes from High-Dose L-Dopa-Treated Parkinson's Disease Patients2005In: Neuroimmunomodulation, no 12, p. 81-84Article in journal (Refereed)
    Abstract [en]

    Objectives: The intracellular (i.c) content of dopamine and its metabolites was measured in the peripheral blood lymphocytes (PBLs) of Parkinson's disease (PD) patients and healthy controls. Methods: Catecholamine levels of PBLs were measured using capillary electrophoresis in healthy controls and PD patients receiving different doses of L-dihydroxyphenylalanine (L-Dopa). Results: Higher i.c. dopamine content was found in lymphocytes from PD patients receiving a high dose of L-Dopa (700 +- 30 mg/day) as compared to lymphocytes from the healthy controls (p = 0.002) and from PD patients treated with a low dose of L-Dopa (400 +- 30 mg/day) (p = 0.022). The dihydroxyphenylacetic acid to dopamine ratio was significantly lower in the high-dose L-Dopa-treated PD patients than in the controls (p = 0.013). Conclusions: These findings suggest that the dopamine content and metabolism in the peripheral lymphocytes of PD patients are influenced by L-Dopa administration. This is the first study in which a dose-related effect of L-Dopa treatment was found in lymphocytes from PD patients.

  • 37.
    Ramström, Margareta
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Bergquist, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Miniaturized proteomics and peptidomics using capillary liquid separation and high resolution mass spectrometry2004In: FEBS Letters, no 567, p. 92-95Article in journal (Refereed)
    Abstract [en]

    Knowledge of the protein and peptide content in a tissue or a body fluid is vital in many areas of medical and biomedical sciences. Information from proteomic and peptidomic studies may reveal alterations in expression due to, e.g., a disease and facilitate the understanding of the pathophysiology and the identification of biological markers. In this minireview, we discuss miniaturized proteomic and peptidomic approaches that have been applied in our laboratory in order to investigate the protein and peptide contents of body fluids (such as plasma, cerebrospinal and amniotic fluid), as well as extracted tissues. The methods involve miniaturized liquid separation, i.e., capillary liquid chromatography and capillary electrophoresis, combined with high resolution mass spectrometry (MS), i.e., Fourier transform ion cyclotron resonance MS. These approaches provide the opportunity to analyze samples of small volumes with high throughput, high sensitivity, good dynamic range and minimal sample handling. Also, the experiments are relatively easy to automate.

  • 38.
    Ramström, Margareta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Hagman, Charlotte
    Tsybin, Youri O.
    Markides, Karin E.
    Håkansson, Per
    Salehi, Albert
    Lundquist, Ingmar
    Håkanson, Rolf
    Bergquist, Jonas
    A novel mass spectrometric approach to the analysis of hormonal peptides in extracts of mouse pancreatic islets2003In: European Journal of Biochemistry, ISSN 0014-2956, Vol. 270, no 15, p. 3146-3152Article in journal (Refereed)
  • 39.
    Ramström, Margareta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Hagman, Charlotte
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Tsybin, Youri O
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Markides, Karin E
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Håkansson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Salehi, Albert
    Lundqvist, Ingmar
    Håkansson, Rolf
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    A novel mass spectrometric approach to analysis of hormonal peptides in extracts of mouse pancreatic islets2003In: European Journal of Biochemistry, ISSN 0014-2956, E-ISSN 1432-1033, Vol. 270, no 15, p. 3146-3152Article in journal (Refereed)
    Abstract [en]

    Liquid chromatography mass spectrometry (LC-MS) is a valuable tool in the analysis of proteins and peptides. The combination of LC-MS with different fragmentation methods provides sequence information on components in complex mixtures. In this work, on-line packed capillary LC electrospray ionization Fourier transform ion cyclotron resonance MS was combined with two complementary fragmentation techniques, i.e. nozzle-skimmer fragmentation and electron capture dissociation, for the determination of hormonal peptides in an acid ethanol extract of mouse pancreatic islets. The most abundant peptides, those derived from proinsulin and proglucagon, were identified by their masses and additional sequence-tag information established their identities. Interestingly, the experiments demonstrated the presence of truncated C-peptides, des-(25-29)-C-peptide and des-(27-31)-C-peptide. These novel findings clearly illustrate the potential usefulness of the described technique for on-line sequencing and characterization of peptides in tissue extracts.

  • 40.
    Ramström, Margareta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Hagman, Charlotte
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Tsybin, Youri O
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Markides, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Håkansson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Salehi, Albert
    Department of Pharmacology, Institute of Physiological Sciences, Lund University.
    Lundquist, Ingmar
    Department of Pharmacology, Institute of Physiological Sciences, Lund University.
    Håkanson, Rolf
    Department of Pharmacology, Institute of Physiological Sciences, Lund University.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    A novel mass spectrometric approach to the analysis of hormonal peptides in extracts of mouse pancreatic islets2003In: European Journal of Biochemistry, ISSN 0014-2956, E-ISSN 1432-1033, Vol. 270, no 15, p. 3146-3152Article in journal (Refereed)
    Abstract [en]

    Liquid chromatography mass spectrometry (LC-MS) is a valuable tool in the analysis of proteins and peptides. The combination of LC-MS with different fragmentation methods provides sequence information on components in complex mixtures. In this work, on-line packed capillary LC electrospray ionization Fourier transform ion cyclotron resonance MS was combined with two complementary fragmentation techniques, i.e. nozzle-skimmer fragmentation and electron capture dissociation, for the determination of hormonal peptides in an acid ethanol extract of mouse pancreatic islets. The most abundant peptides, those derived from proinsulin and proglucagon, were identified by their masses and additional sequence-tag information established their identities. Interestingly, the experiments demonstrated the presence of truncated C-peptides, des-(25-29)-C-peptide and des-(27-31)-C-peptide. These novel findings clearly illustrate the potential usefulness of the described technique for on-line sequencing and characterization of peptides in tissue extracts.

  • 41.
    Ramström, Margareta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Ivonin, Igor
    Johansson, Anders
    Askmark, Håkan
    Markides, Karin E.
    Zubarev, Roman
    Håkansson, Per
    Aquilonius, Sten-Magnus
    Bergquist, Jonas
    Cerebrospinal fluid protein patterns in neurodegenerative disease revealed by liquid chromatography Fourier transform ion cyclotron resonance mass spectrometry2004In: Proteomics, Vol. 4, no 12, p. 4010-4018Article in journal (Refereed)
  • 42.
    Ramström, Margareta
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics. Analytisk kemi.
    Ivonin, Igor
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Johansson, Anders
    Medicinska vetenskapsområdet, Faculty of Medicine, Department of Neuroscience. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics.
    Askmark, Håkan
    Medicinska vetenskapsområdet, Faculty of Medicine, Department of Neuroscience. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics.
    Zubarev, Roman
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Håkansson, Per
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Aquilonius, Sten-Magnus
    Medicinska vetenskapsområdet, Faculty of Medicine, Department of Neuroscience. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics.
    Bergquist, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics. Analytisk kemi.
    Cerebrospinal fluid protein patterns in neurodegenerative disease revealed by liquid chromatography-Fourier transform ion cyclotron resonance mass spectrometry2004In: Proteomics, no 4, p. 4010-4018Article in journal (Refereed)
    Abstract [en]

    This study demonstrates the power of a novel proteomic approach developed for the detection and identification of biological markers in body fluids. The goal was to observe alterations in the protein patterns of cerebrospinal fluid (CSF) related to amyotrophic lateral sclerosis (ALS), a neuro-degenerative disorder with unknown etiology. In the experiments, tryptic digests of CSF from patients and healthy controls were analyzed by on-line capillary liquid chromatography-Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Typically, around 4000 peptides were detected in one such experiment, and a pattern recognition program was constructed for the data analysis to distinguish mass chromatograms from patients and controls. This strategy was evaluated comparing the peptide patterns of CSF spiked in vitro with a biomarker, with control CSF. The patterns were clearly separated and the tryptic peptides of the biomarker were successfully selected as characteristic peaks. Hence, the method was applied to compare mass chromatograms of CSF from 12 ALS-patients and 10 matched healthy controls. While no biomarker alone could be identified from the characteristic peaks, we were able to assign 4 out of 5 unknown samples correctly (i.e. 80% correctly diagnosed, 20% false-negative), and it would be 100% if we reject a possible outlier believed to be caused by an occlusion in the spinal CSF compartment. These findings are very promising, although the clinical relevance is not fully established due to the low number of unknown samples analyzed. In addition to the diagnostic potential, these results may be important steps towards understanding the neurodegenerative process.

  • 43.
    Ramström, Margareta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Palmblad, Magnus
    Markides, Karin E.
    Håkansson, Per
    Bergquist, Jonas
    Protein identification in cerebrospinal fluid using packed capillary liquid chromatography Fourier transform ion cyclotron resonance mass spectrometry2003In: Proteomics, ISSN 1615-9853, Vol. 3, no 2, p. 184-190Article in journal (Refereed)
  • 44. Svedberg, Malin
    et al.
    Pettersson, Andreas
    Nilsson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Bergquist, Jonas
    Nyholm, Leif
    Nikolajeff, Fredrik
    Markides, Karin
    Sheathless electrospray from polymer microchips2003In: Analytical Chemistry, ISSN 0003-2700, Vol. 75, no 15, p. 3934-3940Article in journal (Refereed)
  • 45.
    Svedberg, Malin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Pettersson, Andreas
    Nilsson, Stefan
    Nyholm, Leif
    Nikolajeff, Fredrik
    Bergquist, Jonas
    Markides, Karin E.
    Sheathless electrospray from polymer microchips2003In: Analytical Chemistry, Vol. 75, no 15, p. 3934-3940Article in journal (Refereed)
  • 46. Svensson, Lena
    et al.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. analytisk kemi.
    Wennerås, Christine
    Neuromodulation of experimental Shigella infection reduces damage to the gut mucosa2004In: Microbes and Infection, no 6, p. 256-264Article in journal (Refereed)
    Abstract [en]

    Bacillary dysentery arises when Shigella invades the colonic and rectal mucosae of the human gut and elicits a strong inflammatory response, which may lead to life-threatening complications. Hence, downregulation of the host inflammatory response is an appealing therapeutical alternative. The gastrointestinal tract is densely innervated, and nerve endings are often found in the vicinity of leukocytes. We have assessed the impact of experimental Shigella infection on levels of neuropeptides in the intestinal mucosa of rabbits. Ligated small intestinal loops were created in rabbits, and either live, pathogenic Shigella flexneri, a nonpathogenic mutant of Shigella, or NaCl was injected into loops. Infection was allowed to proceed for 8 or 16 h, after which the rabbits were sacrificed and intestinal biopsies collected. Tissue destruction, fluid secretion and degree of bacterial invasion were monitored. Intestinal biopsies were homogenized, and levels of the neuropeptides calcitonin gene-related peptide, substance P, peptide YY (PYY), vasoactive intestinal peptide, somatostatin, galanin, motilin and neurotensin were measured by radioimmunoassay. Loops exposed to invasive Shigella had 5.7 times lower levels of PYY (P=0.0095) than loops exposed to NaCl, after 16 h of infection. The levels of the other neuropeptides tested were unchanged. Inhibition of nicotinic cholinergic neurotransmission partly protected the intestinal mucosa from destruction elicited by invasive Shigella. These findings indicate that a tissue-invasive bacterium such as Shigella, which is strictly localized to the intestinal mucosa, activates intramural nerve reflexes that presumably involve a nicotinic synapse as well as the neuropeptide PYY.

  • 47.
    Thorslund, Sara
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science. Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Materialvetenskap.
    Sanchez, Javier
    Medicinska vetenskapsområdet, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science. Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Larsson, Rolf
    Medicinska vetenskapsområdet, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science. Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Nikolajeff, Fredrik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science. Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. M.
    Bergquist, Jonas
    Department of Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science. Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Analytisk kemi.
    Bioactive heparin immobilized onto microfluidic channels in poly(dimethylsiloxane) results in hydrophilic surface properties,2005In: Colloids and Surfaces B: Biointerfaces, Vol. 46, p. 106-113Article in journal (Refereed)
  • 48.
    Thorslund, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Sanchez, Javier
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Larsson, Rolf
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Nikolajeff, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Functionality and stability of heparin immobilized onto poly(dimethylsiloxane)2005In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 45, no 2, p. 76-81Article in journal (Refereed)
    Abstract [en]

    Poly(dimethylsiloxane) (PDMS) has become an attractive material when working in the field of microfluidics, mainly because of the rapid prototyping process it involves. The increased surface volume ratio in microchannels makes the interaction between sample and material surface highly important, evident when handling complex biological samples such as plasma or blood. This study demonstrates a new grade of non-covalent heparin surface that adds efficient anticoagulant property to the PDMS material. The surface modification is a simple and fast one-step process performed at neutral pH, optimal when working with closed microsystems. The heparin formed a uniform and functional coating on hydrophobic PDMS with comparatively high level of antithrombin-binding capacity. In addition, long-term studies revelaed that the immobilized heparin was more or less stable in the microchannels over a time of three weeks. Recalcified plasma in contact with native PDMS showed complete coagulation after 1 h, while no fibrin formation was detected in plasma incubated on heparin-coated PDMS within the same time. In conclusion, we see the heparin coating developed and evaluated in this study as a tool that greatly facilitates the use of PDMS in microfluidics dealing with plasma or blood samples.

  • 49.
    Törnkvist, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Sjöberg, Per J. R.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Markides, Karin E.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Analysis of catecholamines and related substances using porous graphitic carbon as separation media in liquid chromatography-tandem mass spectrometry2004In: Journal of Chromotography B, Vol. 801, no 2, p. 323-329Article in journal (Refereed)
    Abstract [en]

    Capillary porous graphitic carbon (PGC) columns have been utilized for separation of several catecholamines and related compounds (i.e. l-tyrosine, l-DOPA, 3-O-methyl-DOPA, dopamine, 3,4-dihydroxy-phenyl-acetic acid (DOPAC), homovanillic acid, noradrenaline, vanillomandelic acid and adrenaline) on-line with electrospray ionization tandem mass spectrometry (ESI–MS/MS). The use of a mobile phase without ion-pairing agents and with high content of organic modifier facilitated the coupling to the selective and sensitive mass spectrometric detection. Minimum detectable sample concentration (MDC sample) for noradrenaline, dopamine and l-tyrosine in a standard solution was estimated to 3, 10 and 30 nM, respectively (3 S/N corresponds to MDQ for l-tyrosine of approximately 8×10−14 mol). The developed strategy was applied for analysis of brain tissue, i.e. a substantia nigra (ns) sample.

  • 50. Ullsten, Sara
    et al.
    Danielsson, Rolf
    Bäckström, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Sjöberg, Per
    Bergquist, Jonas
    Urine profiling using capillary electrophoresis-mass spectrometry and multivariate data analysis2006In: Urine profiling using capillary electrophoresis-mass spectrometry and multivariate data analysis, ISSN 0021-9673, Vol. 1117, no 1, p. 6-Article in journal (Refereed)
12 1 - 50 of 65
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