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  • 51.
    Cedergren, Jan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rheumatology . Linköping University, Faculty of Health Sciences.
    Forslund, Tony
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Sundqvist, Tommy
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Skogh, Thomas
    Linköping University, Department of Clinical and Experimental Medicine, Rheumatology . Linköping University, Faculty of Health Sciences.
    Oxidative activation of human neutrophils by type-1-collagen-coated particles is influenced by nitric oxide production and modulated by endogenous arginase2007In: Journal of Leukocyte Biology, ISSN 0741-5400, E-ISSN 1938-3673Article in journal (Refereed)
  • 52.
    Chirica, Laura C.
    et al.
    Department of Chemistry, Biochemistry, Umeå University, Umeå, Sweden.
    Petersson, Christoffer
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Hurtig, Marina
    Department of Odontology, Umeå University, Umeå, Sweden.
    Jonsson, Bengt-Harald
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Borén, Thomas
    Department of Odontology, Umeå University, Umeå, Sweden.
    Lindskog, Sven
    Department of Chemistry, Biochemistry, Umeå University, Umeå, Sweden.
    Expression and localization of α- and β-carbonic anhydrase in Helicobacter pylori2002In: Biochimica et Biophysica Acta - Proteins and Proteomics, ISSN 1570-9639, E-ISSN 1878-1454, Vol. 1601, no 2, p. 192-199Article in journal (Refereed)
    Abstract [en]

    Helicobacter pylori, the causative agent of peptic ulcer disease, expresses two different forms of the zinc-containing enzyme carbonic anhydrase (CA) (α and β), catalyzing the reversible hydration of CO2. Presumably, the high CO2 requirement of H. pylori implies an important role for this enzyme in the bacterial physiology. In this paper, expression of the CAs has been analyzed in three different strains of the bacterium, 26695, J99 and 17.1, and appears to be independent of CO2 concentration in the investigated range (0.1–10%). Presence of the potent and highly specific CA inhibitor, acetazolamide, in the medium does not seem to inhibit bacterial growth at the given sulfonamide concentration. Moreover, the localization and distribution of the α-CA was analyzed by immunonegative staining, while SDS-digested freeze-fracture immunogold labelling was used for the β-form of the enzyme. The latter method has the advantage of allowing assessment of protein localization to distinct cell compartments and membrane structures. The resulting electron microscopy images indicate a localization of the β-CA in the cytosol, on the cytosolic side of the inner membrane and on the outer membrane facing the periplasmic space. The α-enzyme was found attached to the surface of the bacterium.

  • 53.
    Dalin, Erik
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Ansker,
    Stockholm vatten.
    Häggström,
    Stockholm vatten.
    Dahlberg, B
    Göteborg vatten.
    Pott, B-M
    Sydvatten.
    Ericsson, P
    Norrvatten.
    Lindgren, Per-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
     Analysmetoder för norovirus i ytvatten:  Utveckling av molekylärbiologisk metodik för detektion och kvantifiering i vatten och slam2010Report (Other academic)
    Abstract [en]

    Viruses causing water-borne outbreaks and concentration methods for viruses in water is described. Analysis methodology for measuring background levels of norovirus in surface water sources has been developed. The detection is performed using an automated molecular analysis chain.

  • 54.
    Davies Forsman, L.
    et al.
    Karolinska Institute, Sweden; Karolinska University, Sweden.
    Schön, Thomas
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences. Linnaeus University, Sweden.
    Simonsson, U. S. H.
    Uppsala University, Sweden.
    Bruchfeld, J.
    Karolinska Institute, Sweden; Karolinska University, Sweden.
    Larsson, Marie C
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Jureen, P.
    Public Health Agency Sweden, Sweden.
    Sturegard, E.
    Regional and University of Labs, Sweden.
    Giske, C. G.
    Karolinska University Hospital, Sweden.
    Angeby, K.
    Karolinska University Hospital, Sweden; University of W Indies, Jamaica.
    Intra- and Extracellular Activities of Trimethoprim-Sulfamethoxazole against Susceptible and Multidrug-Resistant Mycobacterium tuberculosis2014In: Antimicrobial Agents and Chemotherapy, ISSN 0066-4804, E-ISSN 1098-6596, Vol. 58, no 12, p. 7557-7559Article in journal (Refereed)
    Abstract [en]

    We investigated the activity of trimethoprim-sulfamethoxazole (SXT) against Mycobacterium tuberculosis, the pathogen that causes tuberculosis (TB). The MIC distribution of SXT was 0.125/2.4 to 2/38 mg/liter for the 100 isolates tested, including multi- and extensively drug-resistant isolates (MDR/XDR-TB), whereas the intracellular MIC90 of sulfamethoxazole (SMX) for the pansusceptible strain H37Rv was 76 mg/liter. In an exploratory analysis using a ratio of the unbound area under the concentration-time curve from 0 to 24 h over MIC (fAUC(0-24)/MIC) using greater than= 25 as a potential target, the cumulative fraction response was greater than= 90% at doses of greater than= 2,400 mg of SMX. SXT is a potential treatment option for MDR/XDR-TB.

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  • 55.
    Devenney, Irene
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics. Linköping University, Faculty of Health Sciences.
    Norrman, Gunilla
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics. Linköping University, Faculty of Health Sciences.
    Forslund, Tony
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Fälth-Magnusson, Karin
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics. Linköping University, Faculty of Health Sciences.
    Sundqvist, Tommy
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Urinary nitric oxide excretion in infants with eczema2010In: Pediatric Allergy and Immunology, ISSN 0905-6157, E-ISSN 1399-3038, Vol. 21, no 1, p. e229-e234Article in journal (Refereed)
    Abstract [en]

    Eczema is characterized by inflammation of the skin and is commonly associated with food allergy. It has been suggested that nitric oxide (NO) is an important player in eczema, food allergy and intestinal inflammation. The aim of this study was to assess the levels of urinary NO breakdown products in infants with eczema and the effect of eczema treatment on NO levels. Ninety-four infants with eczema, 58 boys and 36 girls, with a mean age of 7.5 ± 5.2 months (mean ± s.d.) at inclusion were examined twice with an interval of 6 wk. The sum of nitrite and nitrate was measured colorimetrically in urinary samples from both visits and compared with clinical data concerning eczema severity, nutrition, gastrointestinal symptoms, asthma and skin prick positivity. The levels of NO products increased significantly from the first to the second visit: 289; 374 μm (median; IQR) vs. 457; 678 μm (median; IQR) (p < 0.001) in parallel with a significant improvement of the eczema. After eczema treatment consisting of skin care and elimination diet during the 6-wk interval between evaluations, the NO levels approached the values previously found in healthy children. The results support previous studies indicating that the homeostasis of nitrogen radicals is disturbed in childhood eczema.

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  • 56.
    Eklund, Daniel
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Persson, Hans Lennart
    Linköping University, Department of Medical and Health Sciences, Pulmonary Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Respiratory Medicine.
    Larsson, Marie C.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology. Linköping University, Faculty of Health Sciences.
    Welin, Amanda
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Idh, Jonna
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Paues, Jakob
    Linköping University, Department of Clinical and Experimental Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences.
    Fransson, Sven-Göran
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping.
    Stendahl, Olle
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Schön, Thomas
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Lerm, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Vitamin D enhances IL-1β secretion and restricts growth of Mycobacterium tuberculosis in macrophages from TB patients2013In: International Journal of Mycobacteriology, ISSN 2212-5531, Vol. 2, no 1, p. 18-25Article in journal (Refereed)
    Abstract [en]

    The emergence of multidrug-resistant strains of Mycobacterium tuberculosis (MTB), the bacterium responsible for tuberculosis (TB), has rekindled the interest in the role of nutritional supplementation of micronutrients, such as vitamin D, as adjuvant treatment. Here, the growth of virulent MTB in macrophages obtained from the peripheral blood of patients with and without TB was studied. The H37Rv strain genetically modified to express Vibrio harveyi luciferase was used to determine the growth of MTB by luminometry in the human monocyte-derived macrophages (hMDMs) from study subjects. Determination of cytokine levels in culture supernatants was performed using a flow cytometry-based bead array technique. No differences in intracellular growth of MTB were observed between the different study groups. However, stimulation with 100 nM 1,25-dihydroxyvitamin D significantly enhanced the capacity of hMDMs isolated from TB patients to control the infection. This effect was not observed in hMDMs from the other groups. The interleukin (IL)-1β and IL-10 release by hMDMs was clearly increased upon stimulation with 1,25-dihydroxyvitamin D. Furthermore, the 1,25-dihydroxyvitamin D stimulation also led to elevated levels of TNF-α (tumor necrosis factor-alpha) and IL-12p40. It was concluded that vitamin D triggers an inflammatory response in human macrophages with enhanced secretion of cytokines, as well as enhancing the capacity of hMDMs from patients with active TB to restrict mycobacterial growth.

  • 57.
    Eklund, Daniel
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Welin, Amanda
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Lerm, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    A medium-throughput microplate-based ex vivo model for measuring intramacrophage growth of mycobacterium tuberculosis in CYTOKINE, vol 48, issue 1-2, pp 14-142009In: CYTOKINE, 2009, Vol. 48, no 1-2, p. 14-14Conference paper (Refereed)
    Abstract [en]

    n/a

  • 58.
    Eklund, Daniel
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Welin, Amanda
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Schon, Thomas
    Kalmar County Hospital.
    Stendahl, Olle
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Huygen, Kris
    Science Institute for Public Health, Belgium .
    Lerm, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Validation of a Medium-Throughput Method for Evaluation of Intracellular Growth of Mycobacterium tuberculosis2010In: Clinical and Vaccine Immunology, ISSN 1556-6811, E-ISSN 1556-679X, Vol. 17, no 4, p. 513-517Article in journal (Refereed)
    Abstract [en]

    Intracellular pathogens such as Mycobacterium tuberculosis have adapted to a life inside host cells, in which they utilize host nutrients to replicate and spread. Ineffective methods for the evaluation of growth of intracellular pathogens in their true environment pose an obstacle for basic research and drug screening. Here we present the validation of a luminometry-based method for the analysis of intramacrophage growth of M. tuberculosis. The method, which is performed in a medium-throughput format, can easily be adapted for studies of other intracellular pathogens and cell types. The use of host cells in drug-screening assays dedicated to find antimicrobials effective against intracellular pathogens permits the discovery of not only novel antibiotics but also compounds with immunomodulatory and virulence-impairing activities, which may be future alternatives or complements to antibiotics.

  • 59.
    Elias, D.
    et al.
    Microbiol. and Tumor Biology Center, Karolinska Institute, Box 280, 17177 Stockholm, Sweden, Swed. Inst. for Infect. Dis. Contr., Stockholm, Sweden, Armauer Hansen Research Institute, Box 1005, Addis Ababa, Ethiopia.
    Akuffo, H.
    Microbiol. and Tumor Biology Center, Karolinska Institute, Box 280, 17177 Stockholm, Sweden.
    Pawlowski, A.
    Swed. Inst. for Infect. Dis. Contr., Stockholm, Sweden.
    Haile, M.
    Swed. Inst. for Infect. Dis. Contr., Stockholm, Sweden.
    Schön, Thomas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Britton, S.
    Department of Medicine, Unit of Infectious Diseases, Karolinska Institute, 17176 Stockholm, Sweden.
    Schistosoma mansoni infection reduces the protective efficacy of BCG vaccination against virulent Mycobacterium tuberculosis2005In: Vaccine, ISSN 0264-410X, E-ISSN 1873-2518, Vol. 23, no 11, p. 1326-1334Article in journal (Refereed)
    Abstract [en]

    We hypothesized that the ability of BCG vaccination to protect against Mycobacterium tuberculosis is less in hosts exposed to chronic helminthes infection compared to unexposed individuals. To test this hypothesis we evaluated the efficacy of BCG vaccination in protecting against M. tuberculosis challenge in Schistosoma mansoni pre-infected mice by analyzing their ability to limit the replication of TB bacilli in the lung and liver and the histology of lung sections. The results show that BCG vaccinated mice with prior S. mansoni infection show significantly higher number of colony forming units of TB bacilli as well as significant reduction in air exchange area in the lung compared to controls. In addition, spleen cells from S. mansoni infected mice were found to produce significantly less IFN-? and nitric oxide when stimulated in vitro with PPD and several fold higher soluble egg antigen (SEA) and Concanavalin A induced IL-4 and IL-5 secretion. Taken together, our data show that S. mansoni infection reduces the protective efficacy of BCG vaccination against M. tuberculosis possibly by attenuation of protective immune responses to mycobacterial antigens and/or by polarizing the general immune responses to the Th2 profile. © 2004 Published by Elsevier Ltd.

  • 60.
    Forsberg, Maria
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Blomgran, Robert
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Lem, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Särndahl, Eva
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Sebti, Said M.
    Drug Discovery Program, H. Lee Moffitt Cancer Center & Research Institute, Department of Oncology, University of South Florida, Tampa.
    Hamilton, Andrew
    Department of Chemistry, Yale University, New Haven, Connecticut .
    Stendahl, Olle
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Zheng, Limin
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Differential effects of invasion by and phagocytosis of Salmonella typhimurium on apoptosis in human macrophages: potential role of Rho–GTPases and Akt2003In: Journal of Leukocyte Biology, ISSN 0741-5400, E-ISSN 1938-3673, Vol. 74, no 4, p. 620-629Article in journal (Refereed)
    Abstract [en]

    In addition to direct activation of caspase-1 and induction of apoptosis by SipB, invasive Salmonella stimulates multiple signaling pathways that are key regulators of host cell survival. Nevertheless, little is known about the relative contributions of these pathways to Salmonella-mediated death of macrophages. We studied human monocytic U937 cells and found that apoptosis was induced by invading wild-type Salmonella typhimurium but not by phagocytosed, serum-opsonized, noninvasive Salmonella mutants. Pretreating U937 cells with inhibitors of tyrosine kinases or phosphatidylinositol-3 kinase (PI-3K) completely blocked phagocytosis of opsonized Salmonella mutants but did not affect invasion by wild-type Salmonella or the apoptosis caused by invasion. However, pretreatment with GGTI-298, a geranylgeranyltransferase-1 inhibitor that prevents prenylation of Cdc42 and Rac1, suppressed Salmonella-induced apoptosis by ∼70%. Transduction of Tat fusion constructs containing dominant-negative Cdc42 or Rac1 significantly inhibited Salmonella-induced cell death, indicating that the cytotoxicity of Salmonella requires activation of Cdc42 and Rac. In contrast to phagocytosis of opsonized bacteria, invasion by S. typhimurium stimulated Cdc42 and Rac1, regardless of the activities of tyrosine- or PI-3K. Moreover, Salmonella infection activated Akt protein in a tyrosine-kinase or PI-3K-dependent manner, and a reduced expression of Akt by antisense transfection rendered the cells more sensitive to apoptosis induced by opsonized Salmonella. These results indicate that direct activation of Cdc42 and Rac1 by invasive Salmonella is a prerequisite of Salmonella-mediated death of U937 cells, whereas the simultaneous activation of Akt by tyrosine kinase and PI-3K during receptor-mediated phagocytosis protects cells from apoptosis.

  • 61.
    Foti, M.
    et al.
    Department of Morphology, Faculty of Medicine, 1211 Geneva 4, Switzerland.
    Phelouzat, M.-A.
    Department of Morphology, Faculty of Medicine, 1211 Geneva 4, Switzerland.
    Holm, A.
    Rasmusson, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Carpentier, J.-L.
    Department of Morphology, Faculty of Medicine, 1211 Geneva 4, Switzerland, Department of Morphology, Centre Médical Universitaire, 1 Rue Michel-Ser-vet, 1211 Geneva 4, Switzerland.
    P56Lck anchors CD4 to distinct microdomains on microvilli2002In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 99, no 4, p. 2008-2013Article in journal (Refereed)
    Abstract [en]

    Cell-surface microvilli play a central role in adhesion, fusion, and signaling processes. Some adhesion and signaling receptors segregate on microvilli but the determinants of this localization remain mostly unknown. In this study, we considered CD4, a receptor involved in immune response and HIV infection, and p56Lck, a CD4-associated tyrosine kinase. Analysis of CD4 trafficking reveals that p56Lck binds tightly to CD4 independently of its activation state and inhibits CD4 internalization. Electron microscopy analysis established that p56Lck mediates CD4 association with microvilli whereas biochemical data indicate that p56Lck expression renders CD4 insoluble by the nonionic detergent Triton X-100. In addition, cytoskeleton-disrupting agent increased CD4 solubility, suggesting the involvement of cytoskeletal elements in CD4 anchoring to microvilli. This concept was supported further by the observation that the lateral mobility of CD4 within the plasma membrane was decreased in cells expressing p56Lck. Finally, isolation of detergent-resistant membranes revealed that the complex CD4-p56Lck is enriched within these domains as opposed to conditions in which CD4 does not interact with p56Lck. In conclusion, our results show that p56Lck targets CD4 to specialized lipid microdomains preferentially localized on microvilli. This localization, which prevents CD4 internalization, might facilitate CD4-mediated adhesion processes and could correspond to the signaling site of the receptor.

  • 62.
    Frye, S.A.
    et al.
    Centre for Molecular Biology and Neuroscience, Institute of Microbiology, University of Oslo, Oslo, Norway, Centre for Molecular Biology and Neuroscience, Institute of Microbiology, Rikshospitalet-Radiumhospitalet Medical Centre, Norway.
    Assalkhou, R.
    Centre for Molecular Biology and Neuroscience, Institute of Microbiology, University of Oslo, Oslo, Norway.
    Collins, R.F.
    Faculty of Life Sciences, The University of Manchester, Sackville Street, Manchester M60 1QD, United Kingdom.
    Ford, R.C.
    Faculty of Life Sciences, The University of Manchester, Sackville Street, Manchester M60 1QD, United Kingdom.
    Petersson, Christoffer
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Derrick, J.P.
    Faculty of Life Sciences, The University of Manchester, Sackville Street, Manchester M60 1QD, United Kingdom.
    Tonjum, T.
    Tønjum, T., Centre for Molecular Biology and Neuroscience, Institute of Microbiology, University of Oslo, Oslo, Norway, Centre for Molecular Biology and Neuroscience, Institute of Microbiology, Rikshospitalet-Radiumhospitalet Medical Centre, Norway.
    Topology of the outer-membrane secretin PilQ from Neisseria meningitidis2006In: Microbiology, ISSN 1350-0872, E-ISSN 1465-2080, Vol. 152, no 12, p. 3751-3764Article in journal (Refereed)
    Abstract [en]

    Neisseria meningitidis is the causative agent of epidemic meningococcal meningitis and septicaemia. Type IV pili are surface organelles that mediate a variety of functions, including adhesion, twitching motility, and competence for DNA binding and uptake in transformation. The secretin PilQ is required for type IV pilus expression at the cell surface, and forms a dodecameric cage-like macromolecular complex in the meningococcal outer membrane. PilQ-null mutants are devoid of surface pili, and prevailing evidence suggests that the PilQ complex facilitates extrusion and retraction of type IV pili across the outer membrane. Defining the orientation of the meningococcal PilQ complex in the membrane is a prerequisite for understanding the structure-function relationships of this important protein in pilus biology. In order to begin to define the topology of the PilQ complex in the outer membrane, polyhistidine insertions in N- and C-terminal regions of PilQ were constructed, and their subcellular locations examined. Notably, the insertion epitopes at residues 205 and 678 were located within the periplasm, whereas residue 656 was exposed at the outer surface of the outer membrane. Using electron microscopy with Ni-NTA gold labelling, it was demonstrated that the insertion at residue 205 within the N-terminus mapped to a site on the arm-like features of the 3D structure of the PilQ multimer. Interestingly, mutation of the same region gave rise to an increase in vancomycin permeability through the PilQ complex. The results yield novel information on the PilQ N-terminal location and function in the periplasm, and reveal a complex organization of the membrane-spanning secretin in vivo. © 2006 SGM.

  • 63.
    Fryland, Linda
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Clinical Immunology.
    Forsberg, Pia
    Linköping University, Department of Clinical and Experimental Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Infectious Diseases in Östergötland.
    Sandin, Linnea
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Wilhelmsson, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Lindblom, Pontus
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Nyman, Dag
    Aland Borrelia Grp.
    Lindgren, Per-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Ernerudh, Jan
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Immunology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Immunology and Transfusion Medicine.
    Ekerfelt, Christina
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Clinical Immunology.
    Biomarkers in blood a few days after a bite by a Borrelia burgdorferi infected tick:: Asymptomatic Borrelia burgdorferi-infected subjects show higher Th1-associated response compared with subjects who later develop Lyme borreliosis2012Manuscript (preprint) (Other academic)
    Abstract [en]

    The clinical outcome following infection with Borrelia (B.) burgdorferi sensu lato (s.l.) differs between individuals, ranging from asymptomatic infection to Lyme borreliosis (LB) with persistent symptoms post-treatment. Previous studies in mice and humans have generated the hypothesis that a successful outcome of B. burgdorferi s.l. infection is associated with an early strong pro-inflammatory T helper (Th)1-like immune response. The aim of this study was to assess the early course of events in B. burgdorferi s.l.-associated inflammation by screening for possible early immune biomarkers in peripheral blood from newly tick-bitten persons. The study subjects bitten by B. burgdorferi s.l.-infected ticks were divided into (1) those later developing clinical LB, (2) those who developed anti-B. burgdorferi s.l. antibodies but not clinical LB, (3) those who neither developed antibodies nor clinical LB. A fourth group consisted of bitten study subjects without development of antibodies or clinical LB. Two sets of samples, both comprising all four groups, were collected in order to repeat the analyses and confirm the data. Sera or plasma collected a few days after the tick bite were analysed for 18 biomarkers (IL-1β, IL-6, CXCL8/IL-8, IL-12p70, IL-17A, IL-27, TNF, CCL18, CCL20, CCL22, CXCL1, CXCL9, CXCL10, CXCL11, calprotectin, MMP-3, MMP-8, MMP-9) by multiplex bead assay and ELISA. In the first set of samples, the neutrophil activation marker calprotectin was increased in subjects who developed clinical LB compared with subjects who developed antibodies against B. burgdorferi s.l. but did not develop LB. However, the finding could not be confirmed in the second set of samples, thus the study failed to identify an early prognostic marker for development of clinical LB. Interestingly, both sets of samples showed increases in two different Th1-associated markers, CXCL10 and IL-12p70, respectively, in subjects who following a bite by a B. burgdorferi s.l.-infected tick developed antibodies against B. burgdorferi s.l. but did not develop LB compared with subjects who developed clinical LB, thus supporting the hypothesis of an early strong Th1-response being important for optimal resolution of B. burgdorferi s.l. infection.

  • 64.
    Fryland, Linda
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Immunology. Linköping University, Faculty of Health Sciences.
    Wilhelmsson, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Lindgren, Per-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Nyman, Dag
    Aland Borrelia Grp.
    Ekerfelt, Christina
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Immunology. Linköping University, Faculty of Health Sciences.
    Forsberg, Pia
    Linköping University, Department of Clinical and Experimental Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Infectious Diseases in Östergötland.
    Low risk of developing Borrelia burgdorferi infection in the south-east of Sweden after being bitten by a Borrelia burgdorferi-infected tick2011In: INTERNATIONAL JOURNAL OF INFECTIOUS DISEASES, ISSN 1201-9712, Vol. 15, no 3, p. E174-E181Article in journal (Refereed)
    Abstract [en]

    Objectives: The risk of developing Lyme borreliosis (LB) from Borrelia burgdorferi sensu lato (Bb)-infected ticks in Sweden is largely unknown. In the current study, we investigated the prevalence of Bb in ticks that had bitten humans and the risk of developing LB from Bb-infected ticks. Methods: Health questionnaires, blood samples, and ticks were collected from 394 tick-bitten study subjects in the County of Ostergotland, Sweden, at the time of the tick bite. Questionnaires and blood samples were also collected 3 months later. Ticks were screened for Bb DNA with PCR, while sera were analyzed for antibodies against Bb using two ELISA assays. Seroconversion, i.e., an at least two-fold increase in anti-Bb antibodies after 3 months, was confirmed using a Strip-Immunoassay. Results: Seventy-five of 397 ticks collected from the study subjects were determined to be Bb-positive. Sixty-four of the tick-bitten subjects had been bitten by Bb-infected ticks. Four of them showed seroconversion and were therefore considered to have an active Bb infection. None of these four subjects had sought health care due to symptoms, but one reported symptoms. Conclusions: Our data suggest that the risk of developing LB after being bitten by a Bb-infected tick is low, and asymptomatic Bb infections appear to be more frequent than symptomatic infections.

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  • 65. Grant, C
    et al.
    Högberg, Lotta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Norrköping.
    Fälth-Magnusson, Karin
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Linköping.
    Grodzinsky, Ewa
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Department of Health and Society, General Practice. Östergötlands Läns Landsting, Local Health Care Services in the West of Östergötland, Unit of Research and Development in Local Health Care, County of Östergötland.
    Sundqvist, Tommy
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Stenhammar, Lars
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Linköping.
    The clinical relevance of duodenal intraepithelial lymphocyte counts in children treated for disease2008In: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227Article in journal (Refereed)
    Abstract [en]

      

  • 66. Grdic, D
    et al.
    Ekman, L
    Schon, K
    Lindgren, K
    Mattsson, J
    Magnusson, Karl-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Ricciardi-Castagnoli, P
    Lycke, N
    Splenic marginal zone dendritic cells mediate the cholera toxin adjuvant effect: Dependence on the ADP-ribosyltransferase activity of the holotoxin2005In: Journal of Immunology, ISSN 0022-1767, E-ISSN 1550-6606, Vol. 175, no 8, p. 5192-5202Article in journal (Refereed)
    Abstract [en]

    The in vivo mechanisms of action of most vaccine adjuvants are poorly understood. In this study, we present data in mice that reveal a series of critical interactions between the cholera toxin (CT) adjuvant and the dendritic cells (DC) of the splenic marginal zone (MZ) that lead to effective priming of an immune response. For the first time, we have followed adjuvant targeting of MZ DC in vivo. We used CT-conjugated OVA and found that the Ag selectively accumulated in MZ DC following i.v. injections. The uptake of Ag into DC was GM1 ganglioside receptor dependent and mediated by the B subunit of CT (CTB). The targeted MZ DC were quite unique in their phenotype: CD11c(+), CD8 alpha(-), CD11b(-), B220(-), and expressing intermediate or low levels of MHC class II and DEC205. Whereas CTB only delivered the Ag to MZ DC, the ADP-ribosyltransferase activity of CT was required for the maturation and migration of DC to the T cell zone, where these cells distinctly up-regulated CD86, but not CD80. This interaction appeared to instruct Ag-specific CD4(+) T cells to move into the B cell follicle and strongly support germinal center formations. These events may explain why CT-conjugated Ag is substantially more immunogenic than Ag admixed with soluble CT and why CTB-conjugated Ag can tolerize immune responses when given orally or at other mucosal sites.

  • 67.
    Gréen,, Anna
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Lönn, Anita
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Holmgren Peterson, Kajsa
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Öllinger, Karin
    Linköping University, Department of Clinical and Experimental Medicine, Experimental Pathology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pathology and Clinical Genetics.
    Rundquist, Ingemar
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Translocation of Histone H1 Subtypes Between Chromatin and Cytoplasm During Mitosis in Normal Human Fibroblasts2010In: Cytometry Part A, ISSN 1552-4922, E-ISSN 1552-4930, Vol. 77A, no 5, p. 478-484Article in journal (Refereed)
    Abstract [en]

    Histone H1 is an important constituent of chromatin which undergoes major structural rearrangements during mitosis. However, the role of H1, multiple H1 subtypes and H1 phosphorylation is still unclear. In normal human fibroblasts, phosphorylated H1 was found located in nuclei during prophase and in both cytoplasm and condensed chromosomes during metaphase, anaphase and telophase as detected by immunocytochemistry. Moreover, we detected remarkable differences in the distribution of the histone H1 subtypes H1.2, H1.3 and H1.5 during mitosis. H1.2 was found in chromatin during prophase, and almost solely in the cytoplasm of metaphase and early anaphase cells. In late anaphase it appeared in both chromatin and cytoplasm, and again in chromatin during telophase. H1.5 distribution pattern resembled that of H1.2, but some H1.5 remained situated in chromatin during metaphase and early anaphase. H1.3 was detected in chromatin in all cell cycle phases. We propose therefore, that H1 subtype translocation during mitosis is controlled by phosphorylation, in combination with H1 subtype inherent affinity. We conclude that H1 subtypes, or their phosphorylated variants, may be signalling molecules in mitosis or that they leave chromatin in a regulated way to give access for chromatin condensing factors or transcriptional regulators during mitosis.

  • 68.
    Hagbom, Marie
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology. Linköping University, Faculty of Health Sciences.
    Istrate, Claudia
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology.
    Engblom, David
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Karlsson, Thommie
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology.
    Rodriguez-Diaz, Jesus
    University of Valencia.
    Buesa, Javier
    University of Valencia.
    Taylor, John A
    University of Auckland.
    Loitto, Vesa
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Ahlman, Hakan
    University of Gothenburg.
    Lundgren, Ove
    University of Gothenburg.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology. Linköping University, Faculty of Health Sciences.
    Rotavirus Stimulates Release of Serotonin (5-HT) from Human Enterochromaffin Cells and Activates Brain Structures Involved in Nausea and Vomiting2011In: PLOS PATHOGENS, ISSN 1553-7366, Vol. 7, no 7Article in journal (Refereed)
    Abstract [en]

    otavirus (RV) is the major cause of severe gastroenteritis in young children. A virus-encoded enterotoxin, NSP4 is proposed to play a major role in causing RV diarrhoea but how RV can induce emesis, a hallmark of the illness, remains unresolved. In this study we have addressed the hypothesis that RV-induced secretion of serotonin (5-hydroxytryptamine, 5-HT) by enterochromaffin (EC) cells plays a key role in the emetic reflex during RV infection resulting in activation of vagal afferent nerves connected to nucleus of the solitary tract (NTS) and area postrema in the brain stem, structures associated with nausea and vomiting. Our experiments revealed that RV can infect and replicate in human EC tumor cells ex vivo and in vitro and are localized to both EC cells and infected enterocytes in the close vicinity of EC cells in the jejunum of infected mice. Purified NSP4, but not purified virus particles, evoked release of 5-HT within 60 minutes and increased the intracellular Ca(2+) concentration in a human midgut carcinoid EC cell line (GOT1) and ex vivo in human primary carcinoid EC cells concomitant with the release of 5-HT. Furthermore, NSP4 stimulated a modest production of inositol 1,4,5-triphosphate (IP(3)), but not of cAMP. RV infection in mice induced Fos expression in the NTS, as seen in animals which vomit after administration of chemotherapeutic drugs. The demonstration that RV can stimulate EC cells leads us to propose that RV disease includes participation of 5-HT, EC cells, the enteric nervous system and activation of vagal afferent nerves to brain structures associated with nausea and vomiting. This hypothesis is supported by treating vomiting in children with acute gastroenteritis with 5-HT(3) receptor antagonists.

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  • 69.
    Hedlund, Sebastian
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Persson, Alexander
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Vujic, Ana
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Fru Che, Karlhans
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology . Linköping University, Faculty of Health Sciences.
    Stendahl, Olle
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Larsson, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology . Linköping University, Faculty of Health Sciences.
    Dendritic cell activation by sensing Mycobacterium tuberculosis-induced apoptotic neutrophils via DC-SIGN2010In: HUMAN IMMUNOLOGY, ISSN 0198-8859, Vol. 71, no 6, p. 535-540Article in journal (Refereed)
    Abstract [en]

    Mycobacterium tuberculosis (Mtb) manipulates cells of the innate immune system to provide the bacteria with a sustainable intracellular niche. Mtb spread through aerosol carrying them deep into the lungs, where they are internalized by phagocytic cells, such as neutrophils (PMNs), dendritic cells (DCs), and macrophages. PMNs undergo accelerated apoptosis after interaction with the bacterium, and apoptotic cells are sequestered by neighboring phagocytes. Removal of aged apoptotic cells because of natural tissue turnover is described as an immunologically silent process facilitating resolution of inflammation and inhibition of DC maturation. Silencing of immune cells could be favorable for intracellular bacteria. The aim of this study was to clarify the interaction between Mtb-induced apoptotic PMNs and DCs, and evaluate whether this interaction follows the proposed anti-inflammatory pathway. In contrast to aged apoptotic cells, Mtb-induced apoptotic PMNs induced functional DC maturation. We found that the cell fraction from Mtb-induced apoptotic PMNs contained almost all stimulatory capacity, suggesting that cell-cell interaction is crucial for DC activation. Inhibitory studies showed that this cell contact-dependent activation required binding of the PMN Mac-1 (CD11b/CD18) to the DC via DC-SIGN and endocytic activity involving the alpha(v)beta(5) but did not involve the scavenger receptor CD36. Taken together, this study demonstrates that the DCs can distinguish between normal and infected apoptotic PMNs via cellular crosstalk, where the DCs can sense the presence of danger on the Mtb-infected PMNs and modulate their response accordingly.

  • 70.
    Hedlund, Sebastian R.
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Persson, Alexander
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Vujic, Ana
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Stendahl, Olle
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Larsson, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology . Linköping University, Faculty of Health Sciences.
    Dendritic cell activation by sensing Mycobacterium tuberculosis-induced apoptotic neutrophils via DC-SIGNManuscript (preprint) (Other academic)
    Abstract [en]

    In Mycobacterium tuberculosis (Mtb)-infected individuals cells of the innate immune system accumulate in the spleen and in granulomas, but how this relates to the protection against Mtb or in the pathogenesis is unknown. Mtb is internalized in the lung by phagocytic cells, such as neutrophils (PMNs), dendritic cells (DCs) and macrophages. PMNs undergo accelerated apoptosis after internalization of the bacterium and are subsequently sequestered by neighbouring phagocytes. Removal of aged apoptotic cells is an immunologically silent process and the aim of this study was to clarify the interaction between Mtb-induced apoptotic PMNs and DCs, and evaluate if this interaction induced functional maturation of the DCs. In fact, Mtb-induced apoptotic PMNs induced DC maturation, whereas exposure to spontaneous apoptotic PMNs had no effect on DCs maturation status. We found that the cell fraction contained almost all stimulatory capacity, suggesting that the cell-cell interaction is crucial for DC activation. Inhibitory studies showed that this cell contact-dependent activation required binding of the PMN Mac-1 (CD11b/CD18) to the DC via DC-SIGN and endocytic activity. Taken together, this study proves that the DCs can distinguish between normal and infected apoptotic PMNs via cellular cross talk, where the DCs can sense the presence of danger on the Mtb-infected PMNs and modulate their response accordingly.

  • 71.
    Hedman, Johannes
    et al.
    Lund University.
    Nordgaard, Anders
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Rasmusson, Birgitta
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics. Linköping University, Faculty of Health Sciences.
    Radstrom, Peter
    Lund University.
    Improved forensic DNA analysis through the use of alternative DNA polymerases and statistical modeling of DNA profiles2009In: BIOTECHNIQUES, ISSN 0736-6205, Vol. 47, no 5, p. 951-958Article in journal (Refereed)
    Abstract [en]

    DNA evidence, linking perpetrators to crime scenes, is central to many legal proceedings. However, DNA samples from crime scenes often contain PCR-inhibitory substances, which may generate blank or incomplete DNA profiles. Extensive DNA purification can be required to rid the sample of these inhibitors, although these procedures increase the risk of DNA loss. Most forensic laboratories use commercial DNA amplification kits (e.g., AmpFlSTR SGM Plus) with the DNA polymerase AmpliTaq Gold as the gold standard. Here, we show that alternative DNA polymerase-buffer systems can improve the quality of forensic DNA analysis and efficiently circumvent PCR inhibition in crime scene samples, without additional sample preparation. DNA profiles from 20 of 32 totally or partially inhibited crime scene saliva samples were significantly improved using Bio-X-Act Short, ExTaq Hot Start, or PicoMaxx High Fidelity instead of AmpliTaq Gold. A statistical model for unbiased quality control of forensic DNA profiles was developed to quantify the results. Our study demonstrates the importance of adjusting the chemistry of the PCR to enhance forensic DNA analysis and diagnostic PCR, providing an alternative to laborious sample preparation protocols.

  • 72. Order onlineBuy this publication >>
    Hollén, Elisabet
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Coeliac Disease in Childhood: On the Intestinal Mucosa and the Use of Oats2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Coeliac disease (CD) is one of our most common chronic diseases in childhood. The disease causes an intense inflammation in the small intestinal mucosa after ingestion of gluten-containing cereals in genetically predisposed individuals. The mucosal lesion in CD is characterised by villous atrophy and crypt hyperplasia, and both the absorptive and the barrier functions of the enterocytes are disturbed. The treatment of CD is a life-long adherence to a gluten-free diet (GFD). The toxic fraction of wheat gluten is gliadin, and there are similar proteins in rye, barley and oats. In oats this protein is called avenin, and it is proposed to be less toxic than the others. The use of oats in CD has been debated, but it is now considered safe for the majority of both children and adults with CD.

    The aims of this thesis were to investigate the humoral and inflammatory reactions to oats in children with CD, and also to study the intestinal mucosa at different stages of the disease.

    In a retrospective study we found that children with CD had antibodies to oats avenin, and that the levels were significantly higher than in controls. The levels attenuated during GFD, and we also showed that there was no crossreactivity between antibodies to oats and gliadin.

    We then used our method for measuring antibodies to avenin in a randomised, double-blind trial of oats given to children with newly diagnosed CD. The children were given either a traditional GFD or a GFD supplemented with oats. There was a rapid decrease in antibody levels in both groups already after three months on diet, and at the end of the study period all but a few had normalised their levels. The same children were also studied using urinary nitric oxide (NO) products as markers for intestinal inflammation. Likewise, these values decreased significantly after three months. At the end of the study four children in the GFD-oats group and one in the standard GFD group still had extremely high concentrations of urinary NO metabolites. Taken together, these studies strengthen the clinical impression that oats can be tolerated by the majority of children with CD, but they also warrant a caution, since there seem to be children that do not tolerate oats in their diet.

    The structure and distribution of occludin and claudins 1-5, tight junction proteins known to play a crucial role in maintaining the barrier function, was studied in biopsy specimens from children at different stages of CD. There was an increased expression of occludin in untreated CD, which reflects the characteristics of crypt cell hyperplasia and altered barrier properties seen in active CD. The findings also indicate that gluten intake does not significantly influence the expression and distribution of claudins 1-5 in coeliac children.

    List of papers
    1. Antibodies to oat prolamines (avenins) in children with coeliac disease
    Open this publication in new window or tab >>Antibodies to oat prolamines (avenins) in children with coeliac disease
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    2003 (English)In: Scandinavian Journal of Gastroenterology, ISSN 0036-5521, Vol. 38, no 7, p. 742-746Article in journal (Refereed) Published
    Abstract [en]

    Background: The use of oats in a gluten-free diet for children with coeliac disease is presently under investigation. In this study we measured the content of antibodies to oat prolamines (avenin) in sera from coeliac children and reference children.

    Methods: Crude avenin was prepared by extraction with ethanol and salt-solution and used as antigen in a three-step ELISA. Sera from 81 children, including 34 children with verified coeliac disease, were analysed for both IgA and IgG antibodies to avenin and gliadin. Sera were also incubated with gliadin before exposure to avenin, and vice versa, to assess a possible cross-reaction between the species. Keyhole limpet hemocyanin (KLH) was used as a negative control.

    Results: Children with coeliac disease on a normal diet had significantly higher levels of antibodies to avenin, both IgG and IgA, than reference children ( P < 0.001) and the levels correlated positively with gliadin antibodies, especially of IgA-type ( r = 0.798). Both anti-avenin and anti-gliadin antibodies were only absorbed by the corresponding protein.

    Conclusions: Children with coeliac disease have antibodies to oat proteins at significantly higher levels than reference children. The absorption test did not indicate a cross-reactivity between the prolamines of wheat and oats. The method will be employed for repeated sampling of anti-avenin antibodies during a prospective interventional study with a gluten-free diet supplemented with oats.

    Keywords
    Anti-avenin Antibodies, Coeliac Disease, Oats
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-14131 (URN)10.1080/00365520310003156 (DOI)
    Available from: 2006-11-06 Created: 2006-11-06 Last updated: 2009-08-18
    2. Coeliac children on a gluten-free diet with or without oats display equal anti-avenin antibody titres
    Open this publication in new window or tab >>Coeliac children on a gluten-free diet with or without oats display equal anti-avenin antibody titres
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    2006 (English)In: Scandinavian Journal of Gastroenterology, ISSN 0036-5521, Vol. 41, no 1, p. 42-47Article in journal (Refereed) Published
    Abstract [en]

    Objective. Recent studies report negligible toxicity of oats in the majority of coeliac disease (CD) patients. It has previously been shown that children with untreated CD have circulating antibodies to oats avenin. In this study we performed serial assessments of anti-avenin antibodies in children under investigation for CD on a gluten-free diet with or without oats.

    Material and methods. The study involved 116 children, randomized to a standard gluten-free diet or a gluten-free diet supplemented with oats. Sera were obtained from 86 children, 48 in the standard gluten-free group and 38 in the gluten-free oats group, of which 33 consumed at least 10 g of oats daily. IgA and IgG anti-avenin antibodies were monitored at 0, 3, 6 and 12 months. Nitric oxide metabolites were measured in 7 patients, with deviating antibody results.

    Results. There was a significant decrease in anti-avenin antibodies in both groups at the end as compared to the beginning of the study, (p<0.001), but no difference was found between the two groups. IgA titres already declined after 3 months. IgG titres, although significantly decreased, remained high in the majority of patients in both groups. Nitric oxide levels were high in four of the analysed samples.

    Conclusions. Oats per se, do not seem to produce a humoral immune reaction in children with CD when given in an otherwise gluten-free diet, indicating that the reaction requires gluten challenge. Anti-avenin antibodies were equal in the two study groups, and these findings strengthen the clinical impression that oats can be tolerated by the majority of patients with CD.

    Keywords
    Anti-avenin antibodies; avenin; coeliac disease; oats
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-14132 (URN)10.1080/00365520510023945 (DOI)
    Available from: 2006-11-06 Created: 2006-11-06 Last updated: 2009-05-19
    3. Urinary nitric oxide during one year of gluten-free diet with or without oats in children with coeliac disease
    Open this publication in new window or tab >>Urinary nitric oxide during one year of gluten-free diet with or without oats in children with coeliac disease
    Show others...
    2006 (English)In: Scandinavian Journal of Gastroenterology, ISSN 0036-5521, Vol. 41, no 11, p. 1272-1278Article in journal (Refereed) Published
    Abstract [en]

    Objective. Although in both adults and children with coeliac disease (CD) it is now recommended that oats be added to their gluten-free diet, there is still some controversy concerning the possible harmful effects of oats in some individuals. In this study concentrations of nitric oxide metabolites were repeatedly measured in the urine of children under investigation for CD, when on a gluten-free diet with or without oats.

    Material and methods. The study included 116 children, randomized to a standard gluten-free diet (GFD-std) or a gluten-free diet supplemented with wheat-free oat products (GFD-oats), over a one-year period. Small-bowel biopsy was performed at the beginning and end of the study. Morning urine samples were collected from 87 children and urinary nitrite/nitrate concentrations were monitored at 0, 3, 6, 9 and 12 months.

    Results. All patients were in clinical remission after the study period. There was a rapid decline in urinary nitrite/nitrate concentrations in both groups as early as after 3 months. No differences were seen between the study groups at any of the checkpoints. However, at the end of the study, the nitrite/nitrate values of 9 children in the GFD-oats group and 8 children in the GFD-std group had not normalized.

    Conclusions. Children with CD on a gluten-free diet with oats display a similar reduction in urinary nitrite/nitrate as those on a traditional gluten-free diet. Some children, however, still demonstrate high nitrite/nitrate excretion after one year on either diet, indicating that long-term follow-up studies of children on an oats-containing diet are needed.

    Keywords
    coeliac disease; NO; oats; urinary nitrite/nitrate
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-14133 (URN)10.1080/00365520600684563 (DOI)
    Available from: 2006-11-06 Created: 2006-11-06 Last updated: 2009-05-19
    4. Increased expression of tight junction associated occludin but not of claudins in untreated coeliac disease in children
    Open this publication in new window or tab >>Increased expression of tight junction associated occludin but not of claudins in untreated coeliac disease in children
    Show others...
    Manuscript (Other academic)
    Identifiers
    urn:nbn:se:liu:diva-14134 (URN)
    Available from: 2006-11-06 Created: 2006-11-06 Last updated: 2010-01-13
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  • 73.
    Hollén, Elisabet
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Forslund, Tony
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Högberg, Lotta
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences.
    Laurin, Pia
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences.
    Stenhammar, Lars
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences.
    Fälth-Magnusson, Karin
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Sundqvist, Tommy
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Urinary nitric oxide during one year of gluten-free diet with or without oats in children with coeliac disease2006In: Scandinavian Journal of Gastroenterology, ISSN 0036-5521, Vol. 41, no 11, p. 1272-1278Article in journal (Refereed)
    Abstract [en]

    Objective. Although in both adults and children with coeliac disease (CD) it is now recommended that oats be added to their gluten-free diet, there is still some controversy concerning the possible harmful effects of oats in some individuals. In this study concentrations of nitric oxide metabolites were repeatedly measured in the urine of children under investigation for CD, when on a gluten-free diet with or without oats.

    Material and methods. The study included 116 children, randomized to a standard gluten-free diet (GFD-std) or a gluten-free diet supplemented with wheat-free oat products (GFD-oats), over a one-year period. Small-bowel biopsy was performed at the beginning and end of the study. Morning urine samples were collected from 87 children and urinary nitrite/nitrate concentrations were monitored at 0, 3, 6, 9 and 12 months.

    Results. All patients were in clinical remission after the study period. There was a rapid decline in urinary nitrite/nitrate concentrations in both groups as early as after 3 months. No differences were seen between the study groups at any of the checkpoints. However, at the end of the study, the nitrite/nitrate values of 9 children in the GFD-oats group and 8 children in the GFD-std group had not normalized.

    Conclusions. Children with CD on a gluten-free diet with oats display a similar reduction in urinary nitrite/nitrate as those on a traditional gluten-free diet. Some children, however, still demonstrate high nitrite/nitrate excretion after one year on either diet, indicating that long-term follow-up studies of children on an oats-containing diet are needed.

  • 74.
    Hollén, Elisabet
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Holmgren Peterson, Kajsa
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Sundqvist, Tommy
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Grodzinsky, Ewa
    Högberg, Lotta
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences.
    Laurin, Pia
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences.
    Stenhammar, Lars
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences.
    Fälth-Magnusson, Karin
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Coeliac children on a gluten-free diet with or without oats display equal anti-avenin antibody titres2006In: Scandinavian Journal of Gastroenterology, ISSN 0036-5521, Vol. 41, no 1, p. 42-47Article in journal (Refereed)
    Abstract [en]

    Objective. Recent studies report negligible toxicity of oats in the majority of coeliac disease (CD) patients. It has previously been shown that children with untreated CD have circulating antibodies to oats avenin. In this study we performed serial assessments of anti-avenin antibodies in children under investigation for CD on a gluten-free diet with or without oats.

    Material and methods. The study involved 116 children, randomized to a standard gluten-free diet or a gluten-free diet supplemented with oats. Sera were obtained from 86 children, 48 in the standard gluten-free group and 38 in the gluten-free oats group, of which 33 consumed at least 10 g of oats daily. IgA and IgG anti-avenin antibodies were monitored at 0, 3, 6 and 12 months. Nitric oxide metabolites were measured in 7 patients, with deviating antibody results.

    Results. There was a significant decrease in anti-avenin antibodies in both groups at the end as compared to the beginning of the study, (p<0.001), but no difference was found between the two groups. IgA titres already declined after 3 months. IgG titres, although significantly decreased, remained high in the majority of patients in both groups. Nitric oxide levels were high in four of the analysed samples.

    Conclusions. Oats per se, do not seem to produce a humoral immune reaction in children with CD when given in an otherwise gluten-free diet, indicating that the reaction requires gluten challenge. Anti-avenin antibodies were equal in the two study groups, and these findings strengthen the clinical impression that oats can be tolerated by the majority of patients with CD.

  • 75.
    Hollén, Elisabet
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Högberg, Lotta
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Norrköping.
    Stenhammar, Lars
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences.
    Fälth-Magnusson, Karin
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Linköping.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Antibodies to oat prolamines (avenins) in children with coeliac disease2003In: Scandinavian Journal of Gastroenterology, ISSN 0036-5521, Vol. 38, no 7, p. 742-746Article in journal (Refereed)
    Abstract [en]

    Background: The use of oats in a gluten-free diet for children with coeliac disease is presently under investigation. In this study we measured the content of antibodies to oat prolamines (avenin) in sera from coeliac children and reference children.

    Methods: Crude avenin was prepared by extraction with ethanol and salt-solution and used as antigen in a three-step ELISA. Sera from 81 children, including 34 children with verified coeliac disease, were analysed for both IgA and IgG antibodies to avenin and gliadin. Sera were also incubated with gliadin before exposure to avenin, and vice versa, to assess a possible cross-reaction between the species. Keyhole limpet hemocyanin (KLH) was used as a negative control.

    Results: Children with coeliac disease on a normal diet had significantly higher levels of antibodies to avenin, both IgG and IgA, than reference children ( P < 0.001) and the levels correlated positively with gliadin antibodies, especially of IgA-type ( r = 0.798). Both anti-avenin and anti-gliadin antibodies were only absorbed by the corresponding protein.

    Conclusions: Children with coeliac disease have antibodies to oat proteins at significantly higher levels than reference children. The absorption test did not indicate a cross-reactivity between the prolamines of wheat and oats. The method will be employed for repeated sampling of anti-avenin antibodies during a prospective interventional study with a gluten-free diet supplemented with oats.

  • 76.
    Holm, Åsa
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Tejle, Katarina
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Gunnarsson, T.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Descoteaux, A.
    INRS - Institut Armand-Frappier, Université du Québec.
    Rasmusson, Birgitta
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Protein C α regulates phagocytosis actin dynamics and phagosomal maturation in macrophagesManuscript (preprint) (Other academic)
    Abstract [en]

    Protein kinase C α (PKCα) participates in F-actin remodeling during phagocytosis and phagosomal maturation in macrophages. Promastigotes of the protozoan parasite Leishmania donovani cause an accumulation of periphagosomal F-actin instead of the normal decrease seen with other prey [1]. This accumulation is dependent on promastigote lipophosphoglycan (LPG), which has several detrimental effects on the cell including inhibition of PKCα activity.

    To directly address the role of PKCα and LPG for actin remodeling in macrophages, we investigated F-actin dynamics in RAW 264.7 macrophages overexpressing a dominant-negative mutant of PKCα (DN PKCα). We found that DN PKCα-overexpressing cells displayed increased levels of cortical F-actin and decreased phagocytic capacity, which was augmented when the cells were subjected to LPG-coated prey. The DN PKCα-overexpressing cells also showed defective breakdown of periphagosomal F-actin and inhibition of phagosomal maturation. The level of periphagosomal F-actin was similar to that of controls subjected to LPG-coated prey. Our results show that PKCα regulates phagocytosis and F-actin turnover in macrophages, and that PKCα-dependent breakdown of periphagosomal F-actin is required for normal phagosomal maturation.

  • 77.
    Holm, Åsa
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Tejle, Katarina
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Gunnarsson, T.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Descoteaux, A.
    INRS—Institut Armand-Frappier, Université du Québec, Laval, Qué., Canada.
    Rasmusson, Birgitta
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Role of protein kinase C α for uptake of unopsonized prey and phagosomal maturation in macrophages2003In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 302, no 4, p. 653-658Article in journal (Refereed)
    Abstract [en]

    Protein kinase C α (PKCα) participates in F-actin remodeling during phagocytosis and phagosomal maturation in macrophages. Leishmania donovani promastigotes, which inhibit phagosomal maturation, cause accumulation of periphagosomal F-actin instead of the dissassembly observed around other prey [Cell. Microbiol. 7 (2001) 439]. This accumulation is induced by promastigote lipophosphoglycan (LPG), which has several effects on macrophages including inhibition of PKCα. To investigate a possible connection between PKCα and LPG’s effects on actin dynamics, we utilized RAW264.7 macrophages overexpressing dominant-negative PKCα (DN PKCα). We found increased cortical F-actin and decreased phagocytic capacity, as well as defective periphagosomal F-actin breakdown and inhibited phagosomal maturation in the DN PKCα-overexpressing cells, effects similar to those seen in controls subjected to LPG-coated prey. The results indicate that PKCα is involved in F-actin turnover in macrophages and that PKCα-dependent breakdown of periphagosomal F-actin is required for phagosomal maturation, and endorse the hypothesis that intracellular survival of L. donovani involves inhibition of PKCα by LPG.

  • 78.
    Holm, Åsa
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Tejle, Katarina
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Descoteaux, A.
    INRS-Institut Armand-Frappier, Université du Québec, Laval, Québec, Canada.
    Rasmusson, Birgitta
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Leishmania donovani lipophosphoglycan causes periphagosomal actin accumulation: correlation with impaired translocation of PKCα and defective phagosome maturation2001In: Cellular Microbiology, ISSN 1462-5814, E-ISSN 1462-5822, Vol. 3, no 7, p. 439-447Article in journal (Refereed)
    Abstract [en]

    Lipophosphoglycan (LPG) is the major surface glycoconjugate of Leishmania donovani promastigotes. The repeating disaccharide–phosphate units of LPG are crucial for promastigote survival inside macrophages and establishment of infection. LPG has a number of effects on the host cell, including inhibition of PKC activity, inhibition of nitric oxide production and altered expression of cytokines. LPG also inhibits phagosomal maturation, a process requiring depolymerization of periphagosomal F-actin. In the present study, we have characterized the dynamics of F-actin during the phagocytosis of L. donovani promastigotes in J774 macrophages. We observed that F-actin accumulated progressively around phagosomes containing wild-type L. donovani promastigotes during the first hour of phagocytosis. Using LPG-defective mutants and yeast particles coated with purified LPG, we obtained evidence that this effect could be attributed to the repeating units of LPG. LPG also disturbed cortical actin turnover during phagocytosis. The LPG-dependent accumulation of periphagosomal F-actin correlated with an impaired recruitment of the lysosomal marker LAMP1 and PKCα to the phagosome. Accumulation of periphagosomal F-actin during phagocytosis of L. donovani promastigotes may contribute to the inhibition of phagosomal maturation by physically preventing vesicular trafficking to and from the phagosome.

  • 79.
    Högberg, Lotta
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Norrköping.
    Danielsson, Lars
    Norrtälje Hospital.
    Jarleman, Stefan
    Astrid Lindgren's Children Hospital.
    Sundqvist, Tommy
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Stenhammar, Lars
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Norrköping.
    Serum zinc in small children with coeliac disease2009In: ACTA PAEDIATRICA, ISSN 0803-5253, Vol. 98, no 2, p. 343-345Article in journal (Refereed)
    Abstract [en]

    In coeliac disease (CD) there is a gluten-induced small bowel enteropathy leading to malabsorption of various nutrients, vitamins and trace elements. Low levels of serum zinc have been reported in adults with untreated CD. In the present study we related the serum concentration of zinc to the morphology of the small bowel mucosa in 58 children, all under 4 years of age and under investigation for coeliac disease. The mean serum concentration of zinc (mean +/- SD; mu mol/L) was significantly lower in children with untreated CD (9.7 +/- 2.0) (n = 11) compared to non-coeliac children without enteropathy (15.1 +/- 2.3) (n = 16) (p &lt; 0.001), coeliac children on a gluten-free diet without enteropathy (14.2 +/- 1.6) (n = 14) (p &lt; 0.001), coeliac children on gluten challenge with enteropathy (14.1 +/- 2.1) (n = 12) (p &lt; 0.001) and coeliac children on gluten challenge without enteropathy (13.8 +/- 1.9) (n = 6) (p &lt; 0.005).

    Conclusion: Serum zinc concentration is decreased in untreated coeliac children with enteropathy and normalizes on gluten-free diet. A low serum zinc value in a child being investigated for possible CD on clinical grounds can thus be used as a complementary marker for enteropathy indicating further investigation with small bowel biopsy. The hypothetical role of zinc in the pathogenesis of CD is discussed.

  • 80.
    Högberg, Lotta
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Norrköping.
    Webb, C
    Lund University.
    Fälth-Magnusson, Karin
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Linköping.
    Forslund, Tony
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Danielsson, L
    Norrtalje Hospital.
    Ivarsson, A
    Umea University.
    Sandstrom, O
    Umea University.
    Sundqvist, Tommy
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Children with screening-detected coeliac disease show increased levels of nitric oxide products in urine2011In: ACTA PAEDIATRICA, ISSN 0803-5253, Vol. 100, no 7, p. 1023-1027Article in journal (Refereed)
    Abstract [en]

    Aim: Increased concentration of nitric oxide (NO) metabolites, nitrite and nitrate, in the urine is a strong indication of ongoing small intestinal inflammation, which is a hallmark of the enteropathy of coeliac disease (CD). It has previously been shown that children with symptomatic, untreated CD have increased levels of NO oxidation products in their urine. The aim of this study was to investigate whether screening-detected, asymptomatic coeliac children display the same urinary nitrite/nitrate pattern. Methods: In a multicenter screening study, serum samples were collected from 7208 12-year-old children without previously diagnosed CD. Sera were analysed for anti-human tissue transglutaminase (tTG) of isotype IgA. Small bowel biopsy was performed in antibody-positive children, yielding 153 new cases of CD. In the screening-detected individuals, the sum of nitrite and nitrate concentrations in the urine was analysed and used as an indicator of NO production. For comparison, 73 children with untreated, symptomatic CD were studied. Results: The nitrite/nitrate levels in children with screening-detected CD and those with untreated symptomatic CD did not differ significantly. Both groups had significantly increased urinary nitrite/nitrate concentrations compared to the children with normal small bowel biopsy (p andlt; 0.001). Conclusion: Children with screening-detected CD have increased production of NO just as children with untreated symptomatic CD. High NO metabolite levels in the urine may indicate a pathogenetic feature of CD and be a marker of major clinical importance.

  • 81. Order onlineBuy this publication >>
    Idh, Jonna
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    The Role of Nitric Oxide in Host Defence Against Mycobacterium tuberculosis: Clinical and Experimental Studies2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Mycobacterium tuberculosis is the causative agent of tuberculosis (TB), responsible for significant morbidity and mortality worldwide, especially in low-income countries. Considering aggravating factors, such as HIV co-infection and emerging drug resistance, new therapeutic interventions are urgently needed. Following exposure to M. tuberculosis, surprisingly few individuals will actually develop active disease, indicating effective defence mechanisms. One such candidate is nitric oxide (NO). The role of NO in human TB is not fully elucidated, but has been shown to have a vital role in controlling TB in animal models.

    The general aim of this thesis was to investigate the role of NO in the immune defence against M. tuberculosis, by combining clinical and experimental studies. In pulmonary TB patients, we found low levels of NO in exhaled air, and low levels of NO metabolites in urine. HIV coinfection decreased levels of exhaled NO even further, reflecting a locally impaired NO production in the lung. Low levels of exhaled NO were associated with a decreased cure rate in HIV-positive TB patients. Household contacts to sputum smear positive TB patient presented the highest levels of both urinary NO metabolites and exhaled NO. Malnutrition, a common condition in TB, may lead to deficiencies of important nutrients such as the amino acid L-arginine, essential for NO production. We therefore assessed the effect of an argininerich food supplement (peanuts) in a clinical trial including pulmonary TB patients, and found that peanut supplementation increased cure rate in HIV-positive TB patients.

    We also investigated NO susceptibility of clinical strains of M. tuberculosis, and its association to clinical outcome and antibiotic resistance. Patients infected with strains of M. tuberculosis with reduced susceptibility to NO in vitro, showed a tendency towards lower rate of weight gain during treatment. Moreover, there was a clear variability between strains in the susceptibility to NO, and in intracellular survival within NO-producing macrophages. A novel finding, that can be of importance in understanding drug resistance and for drug development, was that reduced susceptibility to NO was associated with resistance to firstline TB drugs, in particular isoniazid and mutations in inhA.

    Taken together, the data presented here show that NO plays a vital role  in human immune defence against TB, and although larger multicentre studies are warranted, arginine-rich food supplementation can be recommended to malnourished HIV co-infected patients on TB treatment.

    List of papers
    1. Nitric oxide production in the exhaled air of patients with pulmonary tuberculosis in relation to HIV co-infection
    Open this publication in new window or tab >>Nitric oxide production in the exhaled air of patients with pulmonary tuberculosis in relation to HIV co-infection
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    2008 (English)In: BMC Infectious Diseases, ISSN 1471-2334, E-ISSN 1471-2334, Vol. 8, no 146Article in journal (Refereed) Published
    Abstract [en]

    Background: Nitric oxide (NO) is essential for host defense in rodents, but the role of NO during tuberculosis (TB) in man remains controversial. However, earlier observations that arginine supplementation facilitates anti-TB treatment, supports the hypothesis that NO is important in the host defense against TB. Local production of NO measured in fractional exhaled air (FeNO) in TB patients with and without HIV co-infection has not been reported previously. Thus, our aim was to investigate levels of FeNO in relation to clinical symptoms and urinary NO metabolites (uNO).

    Methods: In a cross sectional study, FeNO and uNO were measured and clinical symptoms, chest x-ray, together with serum levels of arginine, tumor necrosis factor alpha (TNF-alpha) and interleukin 12 (IL-12) were evaluated in sputum smear positive TB patients (HIV+/TB, n = 36, HIV-/TB, n = 59), their household contacts (n = 17) and blood donors (n = 46) from Gondar University Hospital, Ethiopia.

    Results: The proportion of HIV-/TB patients with an increased FeNO level (> 25 ppb) was significantly higher as compared to HIV+/TB patients, but HIV+/TB patients had significantly higher uNO than HIV-/TB patients. HIV+ and HIV-/TB patients both had lower levels of FeNO compared to blood donors and household contacts. The highest levels of both uNO and FeNO were found in household contacts. Less advanced findings on chest x-ray, as well as higher sedimentation rate were observed in HIV+/TB patients as compared to HIV-/TB patients. However, no significant correlation was found between FeNO and uNO, chest x-ray grading, clinical symptoms, TNF-alpha, IL-12, arginine levels or sedimentation rate.

    Conclusion: In both HIV negative and HIV co infected TB patients, low levels of exhaled NO compared to blood donors and household were observed. Future studies are needed to confirm whether low levels of exhaled NO could be a risk factor in acquiring TB and the relative importance of NO in human TB.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-16238 (URN)10.1186/1471-2334-8-146 (DOI)
    Note
    Original Publication: Jonna Idh, Anna Westman, Daniel Elias, Feleke Moges, Assefa Getachew, Aschalew Gelaw, Tommy Sundqvist, Tony Forslund, Addis Alemu, Belete Ayele, Ermias Diro, Endalkachew Melese, Yared Wondmikun, Sven Britton, Olle Stendahl and Thomas Schoen, Nitric oxide production in the exhaled air of patients with pulmonary tuberculosis in relation to HIV co-infection, 2008, BMC INFECTIOUS DISEASES, (8), 146. http://dx.doi.org/10.1186/1471-2334-8-146 Publisher: BioMed Central http://www.biomedcentral.com/Available from: 2009-01-16 Created: 2009-01-09 Last updated: 2017-12-14Bibliographically approved
    2. Effects of a food supplement rich in arginine in patients with smear positive pulmonary tuberculosis - A randomised trial
    Open this publication in new window or tab >>Effects of a food supplement rich in arginine in patients with smear positive pulmonary tuberculosis - A randomised trial
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    2011 (English)In: Tuberculosis, ISSN 1472-9792, E-ISSN 1873-281X, Vol. 91, no 5, p. 370-377Article in journal (Refereed) Published
    Abstract [en]

    In tuberculosis (TB), the production of nitric oxide (NO) is confirmed but its importance in host defense is debated. Our aim was to investigate whether a food supplement rich in arginine could enhance clinical improvement in TB patients by increased NO production. Smear positive TB patients from Gondar, Ethiopia (n = 180) were randomized to a food supplementation rich in arginine (peanuts, equivalent to 1 g of arginine/day) or with a low arginine content (wheat crackers, locally called daboqolo) during four weeks. The primary outcome was cure rate according to the WHO classification and secondary outcomes were sputum smear conversion, weight gain, sedimentation rate, reduction of cough and chest X-ray improvement as well as levels of NO in urine (uNO) or exhaled air (eNO) at two months. There was no effect of the intervention on the primary outcome (OR 1.44, 95% CI: 0.69-3.0, p = 0.39) or secondary outcomes. In the subgroup analysis according to HIV status, peanut supplemented HIV+/TB patients showed increased cure rate (83.8% (31/37) vs 53.1% (17/32), p andlt; 0.01). A low baseline eNO (andlt; 10 ppb) in HIV+/TB patients was associated with a decreased cure rate. We conclude that nutritional supplementation with a food supplement rich in arginine did not have any overall clinical effect. In the subgroup of HIV positive TB patients, it significantly increased the cure rate and as an additional finding in this subgroup, low initial levels of NO in exhaled air were associated with a poor clinical outcome but this needs to be confirmed in further studies.

    Place, publisher, year, edition, pages
    Elsevier, 2011
    Keywords
    Nitric oxide, Arginine, Nutritional supplementation, Tuberculosis, Interleukin 10
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-71556 (URN)10.1016/j.tube.2011.06.002 (DOI)000295462300004 ()
    Note
    Funding Agencies|Swedish Heart and Lung Foundation||Swedish SAREC/SIDA foundation||Swedish Research Council||Available from: 2011-10-21 Created: 2011-10-21 Last updated: 2017-12-08Bibliographically approved
    3. Resistance to First-Line Anti-TB Drugs is Associated with Reduced Nitric Oxide Susceptibility in Mycobacterium tuberculosis
    Open this publication in new window or tab >>Resistance to First-Line Anti-TB Drugs is Associated with Reduced Nitric Oxide Susceptibility in Mycobacterium tuberculosis
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    2012 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 1, p. e39891-Article in journal (Refereed) Published
    Abstract [en]

    Background and objective: The relative contribution of nitric oxide (NO) to the killing of Mycobacterium tuberculosis in human tuberculosis (TB) is controversial, although this has been firmly established in rodents. Studies have demonstrated that clinical strains of M. tuberculosis differ in susceptibility to NO, but how this correlates to drug resistance and clinical outcome is not known.

    Methods: In this study, 50 sputum smear- and culture-positive patients with pulmonary TB in Gondar, Ethiopia were included. Clinical parameters were recorded and drug susceptibility profile and spoligotyping patterns were investigated. NO susceptibility was studied by exposing the strains to the NO donor DETA/NO.

    Results: Clinical isolates of M. tuberculosis showed a dose- and time-dependent response when exposed to NO. The most frequent spoligotypes found were CAS1-Delhi and T3_ETH in a total of nine known spoligotypes and four orphan patterns. There was a significant association between reduced susceptibility to NO (>10% survival after exposure to 1mM DETA/NO) and resistance against first-line anti-TB drugs, in particular isoniazid (INH). Patients infected with strains of M. tuberculosis with reduced susceptibility to NO showed no difference in cure rate or other clinical parameters, but a tendency towards lower rate of weight gain after two months of treatment.

    Conclusion: There is a correlation between resistance to first-line anti-TB drugs and reduced NO susceptibility in clinical strains of M. tuberculosis. Further studies including the mechanisms of reduced NO susceptibility are warranted and could identify targets for new therapeutic interventions.

    Place, publisher, year, edition, pages
    Public Library of Science, 2012
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-77129 (URN)10.1371/journal.pone.0039891 (DOI)000305892100124 ()
    Available from: 2012-05-07 Created: 2012-05-07 Last updated: 2017-12-07Bibliographically approved
    4. Susceptibility of Clinical Strains of Mycobacterium tuberculosis to Reactive Nitrogen Species in Activated Macrophages
    Open this publication in new window or tab >>Susceptibility of Clinical Strains of Mycobacterium tuberculosis to Reactive Nitrogen Species in Activated Macrophages
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    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Background: Nitric oxide (NO) is produced in macrophages by the inducible NO synthase (iNOS) upon activation by pro-inflammatory cytokines. NO has been shown to be essential for the control of Mycobacterium tuberculosis infection in murine models whereas its importance in man is not as clear. There is a lack of studies regarding the susceptibility to reactive nitrogen species (RNS) in clinical strains of M. tuberculosis and the relation to first-line drug resistance, such as to isoniazid (INH). The aim of this study was to explore susceptibility to RNS and intracellular survival of clinical strains of M. tuberculosis, with or without INH resistance.

    Method: Seven clinical strains of M. tuberculosis were transformed with the pSMT1-plasmid encoding Vibrio harveyi luciferase. Survival was analysed by luminometry following exposure to the NO donor DETA/NO or peroxynitrite (SIN-1). Intracellular killing was studied in murine macrophages (RAW 264.7) activated with interferon gamma (IFN-γ) and lipopolysaccharide (LPS).

    Results: There was a significant effect on growth control of M. tuberculosis strains upon macrophage activation, which showed variability among clinical isolates. In the cell-free system, all strains showed a dose-dependent susceptibility to DETA/NO and SIN-1, and clinical strains were in general more resistant than H37Rv to DETA/NO. INH-resistant strains with an inhA mutation were significantly more tolerant to DETA/NO than inhA wild type.

    Conclusion: Reactive nitrogen species inhibited growth of clinical M. tuberculosis isolates both in an intra- and extracellular model with significant difference between strains. Increased tolerance to NO was associated with isoniazid resistance mediated by inhA.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-77131 (URN)
    Available from: 2012-05-07 Created: 2012-05-07 Last updated: 2012-05-07Bibliographically approved
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    The Role of Nitric Oxide in Host Defence Against Mycobacterium tuberculosis: Clinical and Experimental Studies
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  • 82.
    Idh, Jonna
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Abate, Ebba
    Gondar College of Medical and Health Sciences, Gondar University, Gondar, Ethiopia; Armauer Hansen Research Institute, Addis Ababa, Ethiopia.
    Westman, Anna
    Department of Infectious Diseases, Karolinska Hospital, Stockholm, Sweden.
    Elias, Daniel
    Armauer Hansen Research Institute, Addis Ababa, Ethiopia.
    Janols, Helena
    Department of Infectious Diseases, Malmö University Hospital, Malmö, Sweden.
    Gelaw, Aschalew
    Gondar College of Medical and Health Sciences, Gondar University, Gondar, Ethiopia.
    Getachew, Assefa
    Gondar College of Medical and Health Sciences, Gondar University, Gondar, Ethiopia.
    Alemu, Shitaye
    Gondar College of Medical and Health Sciences, Gondar University, Gondar, Ethiopia.
    Aseffa, Abraham
    Armauer Hansen Research Institute, Addis Ababa, Ethiopia.
    Britton, Sven
    Department of Infectious Diseases, Karolinska Hospital, Stockholm, Sweden.
    Stendahl, Olle
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Schön, Thomas
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Kinetics of the QuantiFERON((R))-TB Gold In-Tube test during treatment of patients with sputum smear-positive tuberculosis in relation to initial TST result and severity of disease2010In: Scandinavian journal of infectious diseases, ISSN 1651-1980, Vol. 42, no 9, p. 650-657Article in journal (Refereed)
    Abstract [en]

    Abstract The QuantiFERON((R))-TB Gold In-Tube test (QFN) measures interferon-gamma production in response to Mycobacterium tuberculosis antigens. Our aim was to assess the kinetics of the QFN and initial tuberculin skin test (TST) result in relation to severity of disease in a tuberculosis (TB) endemic area. Smear-positive TB patients (n = 71) were recruited at Gondar University Hospital, Ethiopia. The TST, QFN, CD4+ cell count and clinical symptoms (TB score) were assessed and followed up during treatment. From baseline to 7 months after treatment, there was a significant decrease in QFN reactivity (93.8% to 62.5% in HIV-negative/TB; 70.3% to 33.3% in HIV-positive/TB patients) down to a level comparable to a control group of blood donors (51.2%). The agreement between TST and QFN was poor in TB patients compared to healthy controls. A negative TST correlated to more advanced TB in contrast to a negative QFN test. We conclude that the QFN reactivity is significantly reduced at the end of treatment against active TB to the background level of healthy blood donors, and that the agreement between TST and QFN is poor including correlation to the severity of disease.

  • 83.
    Idh, Jonna
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Lerm, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Raffetseder, Johanna
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Eklund, Daniel
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Larsson, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology. Linköping University, Faculty of Health Sciences.
    Pienaar, Elsje
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Forslund, Tony
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Werngren, Jim
    Department of Preparedness, Unit of Highly Pathogenic Microorganisms, Swedish Institute for Communicable Disease Control, Sweden.
    Juréen, Pontus
    Department of Preparedness, Swedish Institute for Communicable Disease Control, Sweden.
    Ängeby, Kristian
    Department of Clinical Microbiology, Karolinska Institute, Karolinska University Hospital, Sweden.
    Sundqvist, Tommy
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Stendahl, Olle
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Schön, Thomas
    Department of Infectious Diseases and Clinical Microbiology, Kalmar County Hospital, Sweden.
    Susceptibility of Clinical Strains of Mycobacterium tuberculosis to Reactive Nitrogen Species in Activated MacrophagesManuscript (preprint) (Other academic)
    Abstract [en]

    Background: Nitric oxide (NO) is produced in macrophages by the inducible NO synthase (iNOS) upon activation by pro-inflammatory cytokines. NO has been shown to be essential for the control of Mycobacterium tuberculosis infection in murine models whereas its importance in man is not as clear. There is a lack of studies regarding the susceptibility to reactive nitrogen species (RNS) in clinical strains of M. tuberculosis and the relation to first-line drug resistance, such as to isoniazid (INH). The aim of this study was to explore susceptibility to RNS and intracellular survival of clinical strains of M. tuberculosis, with or without INH resistance.

    Method: Seven clinical strains of M. tuberculosis were transformed with the pSMT1-plasmid encoding Vibrio harveyi luciferase. Survival was analysed by luminometry following exposure to the NO donor DETA/NO or peroxynitrite (SIN-1). Intracellular killing was studied in murine macrophages (RAW 264.7) activated with interferon gamma (IFN-γ) and lipopolysaccharide (LPS).

    Results: There was a significant effect on growth control of M. tuberculosis strains upon macrophage activation, which showed variability among clinical isolates. In the cell-free system, all strains showed a dose-dependent susceptibility to DETA/NO and SIN-1, and clinical strains were in general more resistant than H37Rv to DETA/NO. INH-resistant strains with an inhA mutation were significantly more tolerant to DETA/NO than inhA wild type.

    Conclusion: Reactive nitrogen species inhibited growth of clinical M. tuberculosis isolates both in an intra- and extracellular model with significant difference between strains. Increased tolerance to NO was associated with isoniazid resistance mediated by inhA.

  • 84.
    Idh, Jonna
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Mekonnen, M.
    Department of Microbiology, Immunology and Parasitology, Addis Ababa University, Ethiopia.
    Abate, E.
    Armauer Hansen Research Institute, Ethiopia.
    Wedajo, W.
    Armauer Hansen Research Institute, Ethiopia.
    Werngren, J.
    Department of Preparedness, Unit of Highly Pathogenic Microorganisms, Swedish Institute for Communicable Disease Control, Sweden.
    Ängeby, K.
    Clinical Microbiology, MTC, Karolinska Institute, Karolinska University Hospital, Sweden.
    Lerm, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Elias, D.
    University of Southern Denmark, Institute of Molecular Medicine, Department of Cancer and Inflammation, Denmark.
    Sundqvist, Tommy
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Aseffa, A.
    Armauer Hansen Research Institute, Ethiopia.
    Stendahl, Olle
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Schön, T.
    Department of Infectious Diseases and Department of Clinical Microbiology, Kalmar County Hospital, Sweden.
    Resistance to First-Line Anti-TB Drugs is Associated with Reduced Nitric Oxide Susceptibility in Mycobacterium tuberculosis2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 1, p. e39891-Article in journal (Refereed)
    Abstract [en]

    Background and objective: The relative contribution of nitric oxide (NO) to the killing of Mycobacterium tuberculosis in human tuberculosis (TB) is controversial, although this has been firmly established in rodents. Studies have demonstrated that clinical strains of M. tuberculosis differ in susceptibility to NO, but how this correlates to drug resistance and clinical outcome is not known.

    Methods: In this study, 50 sputum smear- and culture-positive patients with pulmonary TB in Gondar, Ethiopia were included. Clinical parameters were recorded and drug susceptibility profile and spoligotyping patterns were investigated. NO susceptibility was studied by exposing the strains to the NO donor DETA/NO.

    Results: Clinical isolates of M. tuberculosis showed a dose- and time-dependent response when exposed to NO. The most frequent spoligotypes found were CAS1-Delhi and T3_ETH in a total of nine known spoligotypes and four orphan patterns. There was a significant association between reduced susceptibility to NO (>10% survival after exposure to 1mM DETA/NO) and resistance against first-line anti-TB drugs, in particular isoniazid (INH). Patients infected with strains of M. tuberculosis with reduced susceptibility to NO showed no difference in cure rate or other clinical parameters, but a tendency towards lower rate of weight gain after two months of treatment.

    Conclusion: There is a correlation between resistance to first-line anti-TB drugs and reduced NO susceptibility in clinical strains of M. tuberculosis. Further studies including the mechanisms of reduced NO susceptibility are warranted and could identify targets for new therapeutic interventions.

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  • 85.
    Idh, Jonna
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Westman, Anna
    Karolinska Hospital.
    Elias, Daniel
    Armauer Hansen Research Institute.
    Moges, Feleke
    Gondar University.
    Getachew, Assefa
    Gondar University.
    Gelaw, Aschalew
    Gondar University.
    Sundqvist, Tommy
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Forslund, Tony
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Alemu, Addis
    Gondar University.
    Ayele, Belete
    Gondar University.
    Diro, Ermias
    Gondar University.
    Melese, Endalkachew
    Gondar University.
    Wondmikun, Yared
    Gondar University.
    Britton, Sven
    Karolinska Hospital.
    Stendahl, Olle
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology.
    Schön, Thomas
    Kalmar City Hospital.
    Nitric oxide production in the exhaled air of patients with pulmonary tuberculosis in relation to HIV co-infection2008In: BMC Infectious Diseases, ISSN 1471-2334, E-ISSN 1471-2334, Vol. 8, no 146Article in journal (Refereed)
    Abstract [en]

    Background: Nitric oxide (NO) is essential for host defense in rodents, but the role of NO during tuberculosis (TB) in man remains controversial. However, earlier observations that arginine supplementation facilitates anti-TB treatment, supports the hypothesis that NO is important in the host defense against TB. Local production of NO measured in fractional exhaled air (FeNO) in TB patients with and without HIV co-infection has not been reported previously. Thus, our aim was to investigate levels of FeNO in relation to clinical symptoms and urinary NO metabolites (uNO).

    Methods: In a cross sectional study, FeNO and uNO were measured and clinical symptoms, chest x-ray, together with serum levels of arginine, tumor necrosis factor alpha (TNF-alpha) and interleukin 12 (IL-12) were evaluated in sputum smear positive TB patients (HIV+/TB, n = 36, HIV-/TB, n = 59), their household contacts (n = 17) and blood donors (n = 46) from Gondar University Hospital, Ethiopia.

    Results: The proportion of HIV-/TB patients with an increased FeNO level (> 25 ppb) was significantly higher as compared to HIV+/TB patients, but HIV+/TB patients had significantly higher uNO than HIV-/TB patients. HIV+ and HIV-/TB patients both had lower levels of FeNO compared to blood donors and household contacts. The highest levels of both uNO and FeNO were found in household contacts. Less advanced findings on chest x-ray, as well as higher sedimentation rate were observed in HIV+/TB patients as compared to HIV-/TB patients. However, no significant correlation was found between FeNO and uNO, chest x-ray grading, clinical symptoms, TNF-alpha, IL-12, arginine levels or sedimentation rate.

    Conclusion: In both HIV negative and HIV co infected TB patients, low levels of exhaled NO compared to blood donors and household were observed. Future studies are needed to confirm whether low levels of exhaled NO could be a risk factor in acquiring TB and the relative importance of NO in human TB.

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  • 86. Immerstrand, C
    et al.
    Nilsson, H
    Lindroth, Margaretha
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Sundqvist, Tommy
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Peterson, KH
    Magnusson, Karl-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Confocal and electron microscopy of melanosome aggregation in Xenopus laevis melanophores2002In: Molecular Biology of the Cell, ISSN 1059-1524, E-ISSN 1939-4586, Vol. 13, p. 2664-Conference paper (Other academic)
  • 87.
    Immerstrand, Charlotte
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Hedlund, Joel
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Sundqvist, Tommy
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Holmgren Peterson, Kajsa
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Image correlation spectroscopy for quantification of pigment aggregationManuscript (preprint) (Other academic)
    Abstract [en]

    In the skin of amphibia, fish, and other organisms, the distribution of the pigment granules within melanophores regulates skin colour. In this study we have applied Image Correlation Spectroscopy (ICS; Petersen et al. 1998; Petersen et al. 1993) to monitor the aggregation of pigment granules. Normally in ICS, images from confocallaser scanning rnicroscopy are used to calculate autocorrelation functions from which the density of fluorescent particles in the image, like membrane receptors, can be obtained. The present study differs from traditional ICS in that the images are obtained by light microscopy and then Gaussian filtered to give the particles the appropriate intensity profile required for ICS analysis. ICS appears to be more sensitive than particle counting and image mean intensity for quantification of the degree of pigment aggregation. This study demonstrates for the first time that ICS can be used to analyse the aggregation of non-fluorescent particles, such as pigment granules in Xenopus laevis melanophores.

  • 88.
    Immerstrand, Charlotte
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Holmgren Peterson, Kajsa
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Jager, Edwin
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Krogh, Magnus
    Micromuscle AB, Linköping.
    Skoglund, Mia
    Micromuscle AB, Linköping.
    Selbing, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Gynecology and Obstetrics in Linköping.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Conjugated-polymer micro- and milliactuators for biological applications2002In: MRS bulletin, ISSN 0883-7694, E-ISSN 1938-1425, Vol. 27, no 6, p. 461-464Article in journal (Refereed)
    Abstract [en]

    The development of new conjugated-polymer tools for the study of the biological realm, and for use in a clinical setting, is reviewed in this article. Conjugated-polymer actuators, based on the changes of volume of the active conjugated polymer during redox transformation, can be used in electrolytes employed in cell-culture media and in biological fluids such as blood, plasma, and urine. Actuators ranging in size from 10 μm to 100 μm suitable for building structures to manipulate single cells are produced with photolithographic techniques. Larger actuators may be used for the manipulation of blood vessels and biological tissue.

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  • 89.
    Jacobson, G M
    et al.
    University of Waikato.
    Voss, L J
    University of Waikato.
    Melin, Sara
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology.
    Cursons, R T M
    University of Waikato.
    Sleigh, J W
    University of Waikato.
    The role of connexin36 gap junctions in modulating the hypnotic effects of isoflurane and propofol in mice2011In: ANAESTHESIA, ISSN 0003-2409, Vol. 66, no 5, p. 361-367Article in journal (Refereed)
    Abstract [en]

    Pandgt;Gap junction blockade is a possible mechanism by which general anaesthetic drugs cause unconsciousness. We measured the sensitivity of connexin36 knockout mice to the hypnotic effects of isoflurane and propofol. The experimental endpoint was recovery of the righting reflex of the anaesthetised animals during 0.2% step-reductions in isoflurane concentration, or following intraperitoneal injection of propofol (100 mg.kg-1). Connexin36 knockout animals were more sensitive to the hypnotic effects of isoflurane than normal wild-type animals. The half maximal effective concentration (EC50) for recovery of righting reflex was 0.37% for connexin36 knockout vs 0.49% for wild-type animals (p andlt; 0.001). For propofol, connnexin36 knockout animals showed more rapid loss of righting reflex than wild-type animals (mean (SD) 2.8 (0.13) vs 3.8 (0.27) min); and young (andlt; 60 days) connexin36 knockout animals remained anaesthetised for longer than young wild-type mice (47.2 (2.9) vs 30.5 (1.7) min; p andlt; 0.00001). These findings suggest that the hypnotic effects of anaesthetic drugs may be moderately enhanced by gap junction blockade.

  • 90.
    Jager, Edwin
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Immerstrand, Charlotte
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Biomedical applications of polypyrrole microactuators: from single-cell clinic to microrobots2000In: 1st Annual International, Conference On Microtechnologies in Medicine and Biology. 2000, IEEE , 2000, p. 58-61Conference paper (Other academic)
    Abstract [en]

    Microtools that will be useful for the positioning and investigation microstructures must operate relevant environments, such as cell culture media or blood plasma. They must also be comparatively strong, and preferably allow a muscle like mode of movement. This is given by a novel family of actuators based on conjugated polymers (like polypyrrole, PPy). By miniaturising these structures using standard photolithographic techniques, the authors can reduce the size down to 10-micrometer dimensions and build mechanically active microdevices. These can be moved and positioned by applying a potential to dope or undope the PPy. These novel structures are now being developed as a unique microactuator technology, suitable for operation in applications coupled to cell biology and biomedicine

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  • 91.
    Janols, Helena
    et al.
    Department of Clinical Sciences, Section for Infectious Diseases, Skåne University Hospital, Lund University, Malmö, Sweden.
    Abate, Ebba
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology.
    Idh, Jonna
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology.
    Senbeto, Meseret
    Department of Medical Laboratory Sciences, University of Gondar, Ethiopia.
    Britton, Sven
    Department of Infectious Diseases, Karolinska Hospital, Stockholm, Sweden.
    Alemu, Shitaye
    Department of Internal Medicine, University of Gondar, Gondar, Ethiopia.
    Aseffa, Abraham
    Armauer Hansen Research Institute (AHRI), Addis Ababa, Ethiopia.
    Stendahl, Olle
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology.
    Schön, Thomas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology.
    Early treatment response evaluated by a clinical scoring system correlates with the prognosis of pulmonary tuberculosis patients in Ethiopia: A prospective follow-up study.2012In: Scandinavian journal of infectious diseases, ISSN 1651-1980, Vol. 44, no 11, p. 828-834Article in journal (Refereed)
    Abstract [en]

    Background: In resource-limited settings the monitoring of tuberculosis (TB) patients is challenging, and early identification of TB patients with a high mortality risk is important. The aim of this study was to investigate prospectively whether early changes in a clinical scoring system (TB score) can predict treatment outcome in Ethiopian patients with pulmonary tuberculosis. Method: TB patients (n = 250) and blood donors (n = 82) were recruited prospectively at Gondar University Hospital, Ethiopia. Clinical scoring was performed using an interview-based questionnaire and clinical examination. Results: Among TB patients (53.6% of whom were HIV co-infected) the median TB score declined from week 0 to week 2 (8 (interquartile range (IQR) 6-9) vs 4 (IQR 2-6)) and dropped to a low level at week 8, which was still significantly higher than that found in blood donors (2 (IQR 1-4) vs 0 (IQR 0-1), p < 0.0001). Patients who died had a significantly higher TB score at week 0, week 2, and week 8 than survivors. Mortality was associated with a failure to achieve a decrease greater than 25% in the TB score at 2 weeks. Baseline CD4 + cell counts (< 200 cells/mm(3)) were associated with mortality but not with initial TB score results. Conclusions: The TB score was increased during the first 2 months of treatment among patients who died. Failure to achieve a greater than 25% decrease in TB score after 2 weeks of treatment was associated with increased mortality. Repeated clinical scoring during the intensive phase of TB treatment could be useful to identify high-risk patients.

  • 92.
    Jarvis, A
    et al.
    Swedish University of Agriculture Science.
    Sundberg, C
    Swedish University of Agriculture Science.
    Milenkovski, S
    Lund University.
    Pell, M
    Swedish University of Agriculture Science.
    Smars, S
    Swedish University of Agriculture Science.
    Lindgren, Per-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Hallin , S
    Swedish University of Agriculture Science.
    Activity and composition of ammonia oxidizing bacterial communities and emission dynamics of NH3 and N2O in a compost reactor treating organic household waste2009In: JOURNAL OF APPLIED MICROBIOLOGY, ISSN 1364-5072 , Vol. 106, no 5, p. 1502-1511Article in journal (Refereed)
    Abstract [en]

    To monitor emissions of NH3 and N2O during composting and link these to ammonia oxidation rates and the community structure of ammonia oxidizing bacteria (AOB).

    A laboratory-scale compost reactor treating organic household waste was run for 2 months. NH3 emissions peaked when pH started to increase. Small amounts of N2O and CH4 were also produced. In total, 16% and less than 1% of the initial N was lost as NH3-N and N2O-N respectively. The potential ammonia oxidation rate, determined by a chlorate inhibition assay, increased fourfold during the first 9 days and then remained high. Initially, both Nitrosospira and Nitrosomonas populations were detected using DGGE analysis of AOB specific 16S rRNA fragments. Only Nitrosomonas europaea was detected under thermophilic conditions, but Nitrosospira populations re-established during the cooling phase.

    Thermophilic conditions favoured high potential ammonia oxidation rates, suggesting that ammonia oxidation contributed to reduced NH3 emissions. Small but significant amounts of N2O were emitted during the thermophilic phase. The significance of different AOBs detected in the compost for ammonia oxidation is not clear.

    This study shows that ammonia oxidation occurs at high temperature composting and therefore most likely reduces NH3 emissions.

  • 93.
    Jenkins, Andrew
    et al.
    Unilabs Telelab, Skien, Norway .
    Hvidsten, Dag
    University Hospital of North Norway, Tromsø, Norway.
    Matussek, Andreas
    County Hospital Ryhov, Jönköping, Sweden.
    Lindgren, Per-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Stuen, Snorre
    Norwegian School of Veterinary Science, Sandnes, Norway .
    Kristiansen, Bjørn-Erik
    Unilabs Telelab, Skien, Norway .
    Borrelia burgdorferi sensu lato in Ixodes ricinus ticks from Norway: evaluation of a PCR test targeting the chromosomal flaB gene2012In: Experimental & applied acarology, ISSN 0168-8162, E-ISSN 1572-9702, Vol. 58, no 4, p. 431-439Article in journal (Refereed)
    Abstract [en]

    A consensus TaqMan real-time PCR test targeting the chromosomal flaB gene of Borrelia burgdorferi sensu lato was constructed. The test was compared with a recently published generic Light Upon eXtension (LUX) 16S rRNA real-time PCR test (Wilhelmsson et al. in J Clin Microbiol 48:4169-4176, 2010) on material consisting of 242 Ixodes ricinus ticks collected from dogs and cats in Northern Norway (n = 139) and Telemark County in Southern Norway (n = 103). Ticks positive in either test were further tested by nested PCR amplification of the 5S-23S rRNA intergenic-spacer region followed by sequencing for species identification. A tick was defined as Borrelia positive if two of three tests were positive. Thirty-four of the 242 (14 %) ticks satisfied this definition of positivity. Of these ticks 32 were positive both in the rRNA and flaB test, while two were positive only in the rRNA test. One tick was positive only in the rRNA test and was considered false positive since PCR for sequencing failed. The sensitivity of the flaB test was 94 % and the specificity 100 %. It was possible to determine the species present using Tm analysis. Among ticks from Northern Norway the prevalence of Borrelia was 13 %, whereas the prevalence in Telemark was 16 %. Among identified species (n = 33) B. afzelii was found in 16 (47 %), B. garinii in 15 (44 %) and B. valaisiana in 2 (6 %) ticks, respectively. The flaB test is a rapid, sensitive and specific test for detection and quantification of Borrelia burgdorferi s.l. in I. ricinus ticks. This is the first report on Borrelia prevalence in I. ricinus in Northern Norway.

  • 94.
    Johansson, Anders
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Kuiper, Jan-Herman
    Keele University, England Robert Jones and Agnes Hunt Orthopaed Hospital, England .
    Sundqvist, Tommy
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Persson, Fredrik
    BioOptico AB, Sweden .
    Speier, Craig
    ConMedical Linvatec, CA USA .
    DAlfonso, David
    ConMedical Linvatec, CA USA .
    Richardson, James B
    Keele University, England Robert Jones and Agnes Hunt Orthopaed Hospital, England .
    Öberg, Åke
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Spectroscopic Measurement of Cartilage Thickness in Arthroscopy: Ex Vivo Validation in Human Knee Condyles2012In: Arthroscopy: The Journal of Arthroscopy And Related, ISSN 0749-8063, E-ISSN 1526-3231, Vol. 28, no 10, p. 1513-1523Article in journal (Refereed)
    Abstract [en]

    Purpose: To evaluate the accuracy of articular cartilage thickness measurement when implementing a new technology based on spectroscopic measurement into an arthroscopic camera. Methods: Cartilage thickness was studied by ex vivo arthroscopy at a number of sites (N = 113) in human knee joint osteoarthritic femoral condyles and tibial plateaus, removed from 7 patients undergoing total knee replacement. The arthroscopic image spectral data at each site were used to estimate cartilage thickness. Arthroscopically derived thickness values were compared with reference cartilage thickness as measured by 3 different methods: needle penetration, spiral computed tomography scanning, and geometric measurement after sample slicing. Results: The lowest mean error (0.28 to 0.30 mm) in the regression between arthroscopic and reference cartilage thickness was seen for reference cartilage thickness less than 1.5 mm. Corresponding values for cartilage thickness less than 2.0 and 2.5 mm were 0.32 to 0.40 mm and 0.37 to 0.47 mm, respectively. Cartilage thickness images-created by pixel-by-pixel regression model calculations applied to the arthroscopic images-were derived to demonstrate the clinical use of a camera implementation. Conclusions: On the basis of this investigation on osteoarthritic material, when one is implementing the spectroscopic method for estimating cartilage thickness into an arthroscopic camera, errors in the range of 0.28 to 0.30 mm are expected. This implementation does not, however, influence the fact that the spectral method performs less well in the cartilage thickness region from 1.5 to 2.5 mm and cannot assess cartilage thicker than 2.5 mm. Clinical Relevance: Imaging cartilage thickness directly in the arthroscopic camera video stream could serve as an interesting image tool for in vivo cartilage quality assessment, in connection with cartilage diagnosis, repair, and follow-up.

  • 95.
    Johansson, Anders
    et al.
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Sundqvist, Tommy
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology.
    Kuiper, J.-H.
    Keele University School of Medicine, Keele, UK .
    Öberg, Åke
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    A spectroscopic approach to imaging and quantification of cartilage lesions in human knee joints2011In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 56, no 6, p. 1865-1878Article in journal (Refereed)
    Abstract [en]

    We have previously described a technology based on diffuse reflectance of broadband light for measuring joint articular cartilage thickness, utilizing that optical absorption is different in cartilage and subchondral bone. This study is the first evaluation of the technology in human material. We also investigated the prospects of cartilage lesion imaging, with the specific aim of arthroscopic integration. Cartilage thickness was studied ex vivo in a number of sites (n = 87) on human knee joint condyles, removed from nine patients during total knee replacement surgery. A reflectance spectrum was taken at each site and the cartilage thickness was estimated using the blue, green, red and near-infrared regions of the spectrum, respectively. Estimated values were compared with reference cartilage thickness values (taken after sample slicing) using an exponential model. Two-dimensional Monte Carlo simulations were performed in a theoretical analysis of the experimental results. The reference cartilage thickness of the investigated sites was 1.60 ± 1.30 mm (mean ± SD) in the range 0–4.2 mm. Highest correlation coefficients were seen for the calculations based on the near-infrared region after normalization to the red region (r = 0.86) and for the green region (r = 0.80).

  • 96.
    Karlsson, Anna
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Einarsson, Peter
    Linköping University, The Tema Institute. Linköping University, Faculty of Arts and Sciences.
    Schnurer, Anna
    Swedish University of Agriculture Science, Sweden .
    Sundberg, Carina
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Arts and Sciences.
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Bo
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Impact of trace element addition on degradation efficiency of volatile fatty acids, oleic acid and phenyl acetate and on microbial populations in a biogas digester2012In: Journal of Bioscience and Bioengineering, ISSN 1389-1723, E-ISSN 1347-4421, Vol. 114, no 4, p. 446-452Article in journal (Refereed)
    Abstract [en]

    The effect of trace element addition on anaerobic digestion of food industry- and household waste was studied using two semi-continuous lab-scale reactors, one (R30+) was supplied with Fe, Co and Ni, while the other (R30) acted as a control. Tracer analysis illustrated that methane production from acetate proceeded through syntrophic acetate oxidation (SAO) in both digesters. The effect of the trace elements was also evaluated in batch assays to determine the capacity of the microorganisms of the two digesters to degrade acetate, phenyl acetate, oleic acid or propionate, butyrate and valerate provided as a cocktail. The trace elements addition improved the performance of the process giving higher methane yields during start-up and early operation and lower levels of mainly acetate and propionate in the R30+ reactor. The batch assay showed that material from R30+ gave effects on methane production from all substrates tested. Phenyl acetate was observed to inhibit methane formation in the R30 but not in the R30+ assay. A real-time PCR analysis targeting methanogens on the order level as well as three SAO bacteria showed an increase in Methanosarcinales in the R30+ reactor over time, even though SAO continuously was the dominating pathway for methane production. Possibly, this increase explains the low VFA-levels and higher degradation rates observed in the R30+ batch incubations. These results show that the added trace elements affected the ability of the microflora to degrade VFAs as well as oleic acid and phenyl acetate in a community, where acetate utilization is dominated by SAO.

  • 97. Order onlineBuy this publication >>
    Karlsson, Thommie
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Water Fluxes and Cell Migration: How Aquaporin 9 Controls Cell Shape and Motility2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Prerequisites for all modes of cell migration are cell-substratum interactions that require a sophisticated interplay of membrane dynamics and cytoskeletal rearrangement. Generally, a migrating cell is polarized with a distinct rear and front, from which it extends a wide and thin membrane protrusion- lamellipodium, small fingerlike projections- filopodia, and membrane blisters- blebs. The development of these structures is primarily driven by cytoskeletal contractions and actin polymerization, which are under regulation of several actin-binding proteins and the small GTPases Cdc42, Rac and Rho. Lamellipodia and filopodia are assumed to arise from polymerizing actin, pushing the membrane forward through a Brownian-ratchet mechanism. However, other models based on shifts in the local hydrostatic pressure have also been suggested since blebs are initially void of actin. Recently, fluxes of water through membrane-anchored water channels, aquaporins (AQPs), have been implicated in cell motility, while they appeared to localize to lamellipodia and facilitate cell locomotion. Indeed, expression of AQP9 was shown to induce filopodia in fibroblasts. Here, we have focused on the effects of AQP9 on cell morphology and motility. By using primarily live cell imaging of GFP-AQP9 and other cytoskeletal components we found that AQP9: (i) enhances cell polarization and migration in a Rac1 and serine11 phosphorylation-dependent manner in neutrophils, (ii) induces and accumulates in filopodia, before actin polymerization, (iii) locally deforms the membrane upon rapid reductions osmolarity, (iv) accumulates in the cell membrane underlying bleb development, (v) induces multiple protrusions and thereby impairs the intrinsic directionality, and (vi) facilitates epithelial wound closure through a mechanism involving swelling and expansion of the monolayer. Based on these findings, we have presented models for how water fluxes through AQPs aids actin polymerization in the formation of membrane protrusions. In summary, these models rely on localized accumulation of ion and water channels that control the influx of water and thereby the buildup of a hydrostatic pressure between the membrane and the cytoskeleton. Upon reaching a critical pressure, it will dislocate the membrane from the cytoskeleton and force it to protrude outwards. Moreover, this will promote a local cytoplasmic gel-to-sol transformation, which facilitates diffusion of cytoskeletal reactants. Hereby, we can furthermore assign to filopodia a role as osmo-sensors, protecting the cell from different osmotic loads. In addition, we have postulated a novel model for wound healing involving force generation by cell swelling. Taken together, this thesis provides the field of cell migration with solid evidence for pivotal roles of water fluxes through AQP9 in particular, but most likely AQPs in general, during cell locomotion and localized volume control.

    List of papers
    1. Aquaporin 9 phosphorylation mediates membrane localization and neutrophil polarization
    Open this publication in new window or tab >>Aquaporin 9 phosphorylation mediates membrane localization and neutrophil polarization
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    2011 (English)In: Journal of Leukocyte Biology, ISSN 0741-5400, E-ISSN 1938-3673, Vol. 90, no 5, p. 963-973Article in journal (Refereed) Published
    Abstract [en]

    Neutrophils are of prime importance in the host innate defense against invading microorganisms by using two primary mechanisms-locomotion toward and phagocytosis of the prey. Recent research points to pivotal roles for water channels known as AQPs in cell motility. Here, we focused on the role of AQP9 in chemoattractant-induced polarization and migration of primary mouse neutrophils and neutrophil-like HL60 cells. We found that AQP9 is phosphorylated downstream of fMLFR or PMA stimulation in primary human neutrophils. The dynamics of AQP9 were assessed using GFP-tagged AQP9 constructs and other fluorescent markers through various live-cell imaging techniques. Expression of WT or the phosphomimic S11D AQP9 changed cell volume regulation as a response to hyperosmotic changes and enhanced neutrophil polarization and chemotaxis. WT AQP9 and S11D AQP9 displayed a very dynamic distribution at the cell membrane, whereas the phosphorylation-deficient S11A AQP9 failed to localize to the plasma membrane. Furthermore, we found that Rac1 regulated the translocation of AQP9 to the plasma membrane. Our results show that AQP9 plays an active role in neutrophil volume regulation and migration. The display of AQP9 at the plasma membrane depends on AQP9 phosphorylation, which appeared to be regulated through a Rac1-dependent pathway.

    Place, publisher, year, edition, pages
    Society for Leukocyte Biology, 2011
    Keywords
    AQP9, cell migration, Rac, water fluxes, osmosis, hydrostatic pressure
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-72257 (URN)10.1189/jlb.0910540 (DOI)000296716000014 ()
    Note
    Funding Agencies|Swedish Research Council-Medicine|2006-74991007-34832010-3045|Swedish Research Council Natural Sciences|2009-6649|European Sciences Foundation (TraPPs-Euromembrane)||CIHR|MOP-86550|CIHR Group||Available from: 2011-11-24 Created: 2011-11-24 Last updated: 2017-12-08
    2. Fluxes of Water through Aquaporin 9 Weaken Membrane-Cytoskeleton Anchorage and Promote Formation of Membrane Protrusions
    Open this publication in new window or tab >>Fluxes of Water through Aquaporin 9 Weaken Membrane-Cytoskeleton Anchorage and Promote Formation of Membrane Protrusions
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    2013 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 4, p. e59901-Article in journal (Refereed) Published
    Abstract [en]

    All modes of cell migration require rapid rearrangements of cell shape, allowing the cell to navigate within narrow spaces in an extracellular matrix. Thus, a highly flexible membrane and a dynamic cytoskeleton are crucial for rapid cell migration. Cytoskeleton dynamics and tension also play instrumental roles in the formation of different specialized cell membrane protrusions, viz. lamellipodia, filopodia and membrane blebs. The flux of water through membrane-anchored water channels, known as aquaporins (AQPs) has recently been implicated in the regulation of cell motility, and here we provide novel evidence for the role of AQP9 in the development of various forms of membrane protrusion. Using multiple imaging techniques and cellular models we show that: (i) AQP9 induced and accumulated in filopodia, (ii) AQP9-associated filopodial extensions preceded actin polymerization, which was in turn crucial for their stability and dynamics, and (iii) minute, local reductions in osmolarity immediately initiated small dynamic bleb-like protrusions, the size of which correlated with the reduction in osmotic pressure. Based on this, we present a model for AQP9-induced membrane protrusion, where the interplay of water fluxes through AQP9 and actin dynamics regulate the cellular protrusive and motile activity of cells.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-90022 (URN)10.1371/journal.pone.0059901 (DOI)000318840100033 ()
    Available from: 2013-03-15 Created: 2013-03-15 Last updated: 2017-12-06Bibliographically approved
    3. Water fluxes through aquaporin-9 prime epithelial cells for rapid wound healing
    Open this publication in new window or tab >>Water fluxes through aquaporin-9 prime epithelial cells for rapid wound healing
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    2013 (English)In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 430, no 3, p. 993-998Article in journal (Refereed) Published
    Abstract [en]

    Cells move along surfaces both as single cells and multi-cellular units. Recent research points toward pivotal roles for water flux through aquaporins (AQPs) in single cell migration. Their expression is known to facilitate this process by promoting rapid shape changes. However, little is known about the impact on migrating epithelial sheets during wound healing and epithelial renewal. Here, we investigate and compare the effects of AQP9 on single cell and epithelial sheet migration. To achieve this, MDCK-1 cells stably expressing AQP9 were subjected to migration assessment. We found that AQP9 facilitated cell locomotion at both the single and multi-cellular level. Furthermore, we identified major differences in the monolayer integrity and cell size upon expression of AQP9 during epithelial sheet migration, indicating a rapid volume-regulatory mechanism. We suggest a novel mechanism for epithelial wound healing based on AQP-induced swelling and expansion of the monolayer.

    Place, publisher, year, edition, pages
    Elsevier, 2013
    Keywords
    Cell migration, Aquaporins, AQP9, Wound healing, Cell motility
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-89749 (URN)10.1016/j.bbrc.2012.11.125 (DOI)000314376100021 ()
    Note

    Funding Agencies|Swedish Research Council for Medicine and Health|2007-34832009-66492010-3045|

    Available from: 2013-03-05 Created: 2013-03-05 Last updated: 2017-12-06