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Biomedical subjects

O Stendahl

Publications and source records attributed to O Stendahl.

At least 109 records · Page 6Linked to original sources
PubMed1983

Role of myeloperoxidase in luminol-dependent chemiluminescence of polymorphonuclear leukocytes.

When polymorphonuclear leukocytes (PMNL) and soluble or particulate matter interact, the cells produce chemiluminescence, linked to activation of the oxidative metabolism of the cells. PMNL isolated from a patient with a myeloperoxidase deficiency were found to produce almost no luminol-dependent chemiluminescence, despite a pronounced production of superoxide anions (O2-). The chemotactic peptide formylmethionyl-leucyl-phenylalanine induced a two-peak chemiluminescence response in control PMNL. The response was modified, both in magnitude and in time-course, when the cells were incubated at 22 degrees C for 120 min. Addition of purified myeloperoxidase to the PMNL lacking this enzyme, before stimulus addition, resulted in a chemiluminescence response. In the response to formylmethionyl-leucyl-phenylalanine, only one peak, corresponding to the initial peak of control PMNL, was found. This indicated that luminol-dependent chemiluminescence is dependent on and directly related to the presence of myeloperoxidase in PMNL and that both intra- and extracellularly located myeloperoxidase has to be taken into account when interpreting the cellular response assayed as chemiluminescence.

Cytochalasin B↗
PubMed1983

Physicochemical properties and blood clearance of human serum albumin conjugated to different extents with dinitrophenyl groups.

Human serum albumin (HSA) conjugated to various extents with dinitrophenyl (DNP) groups and labelled with 125I was studied with regard to physicochemical properties and blood clearance after intravenous injection in mice. Increasing the degree of DNP conjugation increased the tendency to hydrophobic interaction, and increased the net negative charge. Heavily DNP-substituted HSA molecules tended to aggregate. The higher the degree of DNP substitution the faster was the conjugate eliminated from the circulation. Blood clearance was independent of serum complement, and was not affected by galactose, N-acetylglucosamine, mannose, alpha-methyl-D-mannoside, or fucose. It is proposed that the differences in blood clearance between the different DNP-HSA conjugates mainly depend upon differences in the tendency to hydrophobic interaction.

Animals↗
PubMed1983

Granulocyte-mediated release of histamine from mast cells. Effect of myeloperoxidase and its inhibition by antiinflammatory sulfone compounds.

During phagocytosis, neutrophilic and eosinophilic granulocytes undergo metabolic activation and degranulation. This leads to accumulation of H2O2 and myeloperoxidase (MPO) or eosinophilic peroxidase (EPO) in the extracellular environment in inflammation. In the present investigation we show that the MPO-H2O2-halide system can degranulate isolated mast cells with release of histamine and 3H-serotonin. This is accomplished both in a system containing purified human MPO and in one containing phagocytosing neutrophils. When using purified MPO and a H2O2-generating system, the release was rapid, with 50% release after less than 20 min. The direct histamine release required less (0.65-2 micrograms/ml) MPO than did the release of 3H-serotonin (1-6 micrograms/ml). The release reaction was inhibited by azide, catalase but not superoxide dismutase. Studying the effect of the antiinflammatory sulfone compounds dapsone and sulfapyridine on the MPO-mediated histamine release, we show effective inhibition of the histamine release at concentrations of 0.025-0.2 mM of sulfone. 5-aminosalicylic acid exhibited some inhibition only in the cell-free system, whereas sulfasalazine was inactive. The antiinflammatory effect of dapsone in dermatitis herpetiformis and sulfasalazine in ulcerative colitis may in part be explained by their inhibitory effects on the granulocyte-mediated histamine release from mast cells in skin and mucosal tissue.

Anti-Inflammatory Agents↗
PubMed1983

Gastrointestinal uptake and blood clearance of antigen in the presence of IgA antibodies.

In selected experiments, IgA antibodies with specificity for dinitrophenyl (DNP) groups appeared to prevent gastrointestinal passage of antigenic fragments of DNP-conjugated protein given orally to mice. The antigen did not, however, pass across the gut as an intact macromolecule even in control animals. IgA was not found to increase the blood clearance of DNP-conjugated protein given intravenously and it is concluded that IgA probably does not have any important role in mediating elimination of macromolecular antigens from the blood.

Administration, Oral↗
PubMed1983

Complement-mediated delay in immune complex clearance from the blood owing to reduced deposition outside the reticuloendothelial system.

The effect of serum complement upon the blood clearance rate and tissue distribution of intravenously injected small immune complexes formed between 125-labelled dinitrophenyl (DNP)-conjugated human serum albumin and rabbit IgG-anti-DNP antibodies was studied in mice. Immune complexes formed in the absence of complement (i.e. in phosphate-buffered saline or in the presence of complement-depleted serum from mice treated with cobra venom factor) were cleared from the blood at a higher rate than was the antigen injected alone. In contrast, immune complexes formed in the presence of fresh normal mouse serum were cleared from the blood at the same rate as was the native antigen. Immune complexes formed in the presence of complement were eliminated mainly by the liver. The complexes formed in the absence of complement also became located to the liver to approximately the same extent, but an even larger proportion of these immune complexes was deposited outside the reticuloendothelial system. It is concluded that serum complement may inhibit IgG-mediated clearance of antigen, probably by increasing the solubility of the complexes, thereby reducing the risk of deposition outside the reticuloendothelial system.

Animals↗
PubMed1982

Physicochemical and functional changes in human leukemic cell line HL-60.

The recently established human promyelocytic cell line HL-60 was induced to differentiate in the present of DMSO. During this process, physicochemical, and functional changes were detected simultaneously. After exposure to DMSO for more than 1 day, the cell volume decreased and the tendency for hydrophobic interaction increased. Using a hydrophobic two-phase system in counter current distribution fashion, it was then possible to separate more mature metamyelocytes and segmented granulocytes from immature myeloblasts and promyelocytes. Increased functional maturity was reflected by increased chemiluminescence (CL) response and phagocytic activity. Using yeast particles opsonized with IgG as stimulating agent, the CL response increased already after 1 day in DMSO, in parallel with increased phagocytosis of these particles. In contrast, C3b-opsonized yeast and phorbol 12-myristate 13-acetate (PMA) did not enhance the CL response conspicuosly until days 3-4. These data suggest that Fc receptor function linked to phagocytosis and the activation of oxidative metabolism develop earlier than that of C3b and PMA. The dissociation between Fc- and PMA-dependent stimulation of the oxidative metabolism may reflect different mechanisms of activation.

Cell Differentiation↗
PubMed1982

Physicochemical surface changes on phagocytic cells during differentiation in relation to chemotaxis and phagocytosis.

During cell differentiation induced by DMSO, the HL-60 cells exhibit certain surface alterations such as increased hydrophobic interaction. Similar changes have been observed in activated alveolar macrophages, and granulocytes exposed to chemoattractant in vivo and in vitro. Whether these surface changes are directly linked to the enhanced chemotactic, oxidative and phagocytic responsiveness is unclear, although increased liability to hydrophobic interaction promotes phagocytic recognition in several systems. From the present data it is evident that oxidative and phagocytic responsiveness are acquired at different stages of differentiation. Detecting physicochemical differences in the surface properties of the HL-60 cells during differentiation may furthermore provide a useful tool for studying subpopulations of cells during differentiation and activation.

Cell Differentiation↗
PubMed1982

Physiochemical properties of polymorphonuclear leukocyte surface structures associated with the f-Met-Leu-Phe receptor.

Surface property changes of polymorphonuclear leukocytes (PMNL) as a result of development of functional receptors to f-Met-Leu-Phe and as a result of f-Met-Leu-Phe binding have been studied by aqueous biphasic partitioning of the cells in systems of dextran and polyethylene glycol (PEG) with part of the PEG exchanged for positively charged or hydrophobic PEG. The Phe was associated with increased exposure of hydrophobic surface structures as well as of negatively charged groups on the PMNL surface. Binding of f-Met-Leu-Phe to the PMNL surface receptors caused hiding of hydrophobic and charged structures, indicating that these properties are of importance in the interaction between PMNL and the chemotactic peptide.

Cell Membrane↗
PubMed1982

Interaction between human polymorphonuclear leukocytes and two different strains of type 1 fimbriae-bearing Escherichia coli.

Two type 1 fimbriae-bearing strains of Escherichia coli, ABU2 (ON:K14) and PN7 (O1:K1), with different underlying physicochemical surface properties were compared for their capacity to interact with human polymorphonuclear leukocytes. Both strains attached strongly to neutrophils in a mannose-sensitive manner. One of the strains, ABU2, with a surface exposing weak negative charge and liability to hydrophobic interaction, was efficiently ingested (65%) and caused a release of reactive oxidative metabolites (chemiluminescence) and lysosomal enzymes. The other strains, PN7, exposing a hydrophilic, negatively charged K antigen and hydrophilic uncharged smooth lipopolysaccharide, resisted phagocytosis (only 25% were ingested) but nevertheless caused a release of reactive oxidative metabolites and lysosomal enzymes to a greater extent than did phagocytosed strain ABU2. These results show that attachment mediated by type 1 fimbriae does not ultimately lead to ingestion. Whether the attached bacteria are being ingested or not depends on their underlying physicochemical surface properties. Furthermore, if the bacteria remain extracellularly attached, they may potentiate the inflammatory process.

Adhesiveness↗
PubMed1982

Effect of in vitro preincubation of polymorphonuclear leukocytes on formylmethionyl-leucyl-phenylalanine-induced chemiluminescence.

When polymorphonuclear leukocytes (PMNL) and soluble or particulate matter interact, the cells produce chemiluminescence. The chemotactic peptide formylmethionyl-leucyl-phenylalanine induced a two-peak chemiluminescence response in PMNL. The response was modified, both in magnitude and in the time course of the response, when PMNL were incubated at 22 degrees C for 15 to 120 min before the addition of stimulus. The cellular response to formylmethionyl-leucyl-phenylalanine was also changed by the addition of cell-free supernatants from stored PMNL suspensions to freshly prepared PMNL before the addition of formylmethionyl-leucyl-phenylalanine. This indicated that PMNL during storage released substances that changed the chemiluminescence response. A similar change could be obtained by addition of purified myeloperoxidase to freshly prepared PMNL before the addition of stimulus, indicating that the myeloperoxidase-hydrogen peroxide system can function as a modulator of the cellular response to chemotactic factors.

Azides↗
PubMed1982

Modulation of polymorphonuclear leukocyte chemiluminescent response to the chemoattractant f-Met-Leu-Phe.

Upon the interaction between polymorphonuclear leukocytes (PMNL) and soluble or particulate matter, the cells become metabolically activated and produce chemiluminescence. To respond with chemiluminescence to the chemotactic peptide formyl-methionyl-leucyl-phenylalanine (f-Met-Leu-Phe), the PMNL required conditioning of the cells at 22 degrees C or higher temperature prior to stimulus addition. This was not required when phorbolmyristate acetate or opsonized yeast particles were used as stimulus. When cell samples were obtained from PMNL suspensions during 240 min from preparation, the chemiluminescence signal triggered by f-Met-Leu-Phe progressively increased. Scatchard plot analysis of the chemiluminescence data indicated that storage of the cells resulted in modulation of both the number of functional receptors and the affinity for the receptor. The importance of receptor function control in the inflammatory process is discussed.

Chemotactic Factors↗
PubMed1982

Complement-mediated inhibition of non-specific aggregation of highly-dinitrophenyl-conjugated human serum albumin.

125I-labelled dinitrophenylated human serum albumin (DNP35HSA) was shown to form large aggregates after incubation either in normal human serum (NHS) containing ethylene diamine tetraacetate (EDTA), or in heat treated NHS, whereas much smaller aggregates were formed after incubation in NHS or NHS containing ethylene glycol tetraacetate (EGTA) and Mg2+. It is proposed that serum complement inhibits the formation of DNP35HSA aggregates after activation of the alternative pathway in the absence of specific antibodies. The phenomenon is probably explained by increased electrostatic repulsion.

Antigen-Antibody Complex↗
PubMed1981

Distribution of actin-binding protein and myosin in polymorphonuclear leukocytes during locomotion and phagocytosis.

Polymorphonuclear (PMN) leukocytes, highly motile ameboid cells vital for mammalian defense against infection, acquire a distinct polarized morphology during locomotion and phagocytosis. An organelle-excluding pseudopod extends in the direction of movement and surrounds objects during phagocytosis. The anterior pseudopod contains a three-dimensional network of actin filaments. Actin-binding protein (ABP) and myosin cause the crosslinking and contraction, respectively, of actin filaments in vitro. We used indirect immunofluorescence to study the redistribution of myosin and ABP molecules in rabbit PMN leukocytes during locomotion and phagocytosis. In unpolarized PMN leukocytes, ABP and myosin had a diffuse distribution with some predilection for the cortex. In polarized PMN leukocytes crawling toward yeast particles, myosin and ABP staining concentrated in the anterior pseudopod. In PMN leukocytes fixed during phagocytosis of the yeast particles, antimyosin and anti-ABP staining concentrated strikingly in the distal portions of the pseudopod embracing the yeasts. Staining for catalase, a cytoplasmic protein in PMN leukocytes, for lactoferrin, a protein of specific granules, and for myeloperoxidase, a protein of azurophilic granules, was not concentrated in pseudopods. Taken together with available morphologic and biochemical information, these findings are consistent with a mechanism wherein interactions of actin, ABP and myosin redistribute cortical cytoplasm into pseudopods involved in locomotion and phagocytosis.

Actins↗
PubMed1981

Physicochemical surface properties of Escherichia coli strains isolated from different types of urinary tract infections.

Escherichia coli strains isolated from three groups of patients with urinary tract infections, such as acute pyelonephritis, acute cystitis, and asymptomatic bacteriuria, were analyzed with respect to their physicochemical surface properties by means of polymer two-phase partitioning in dextran-polyethylene glycol systems and hydrophobic interaction chromatography on Octyl-Sepharose. Strains causing acute pyelonephritis constituted a homogenous group which, depending on the growth conditions, demonstrated smooth-type lipopolysaccharide, elevated negative charge, and liability to hydrophobic interaction, whereas strains isolated from acute cystitis and asymptomatic bacteriuria showed a more heterogenous pattern.

Adolescent↗