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Biomedical subjects

O Stendahl

Publications and source records attributed to O Stendahl.

At least 91 records · Page 5Linked to original sources
PubMed1985

Effect of monosaccharides and ethyleneglycol on the interaction between Escherichia coli bacteria and Octyl-Sepharose.

Combined effects of monosaccharides and reduced surface tension of the medium were studied in relation to the hydrophobic binding of Escherichia coli bacteria, with and without mannose-specific structures. Hydrophobic binding was analyzed by hydrophobic interaction chromatography on Octyl-Sepharose. The results showed that ethyleneglycol, as well as mannose, reduced the hydrophobic interaction of the bacteria with mannose-specific structures. This effect was potentiated by combining ethyleneglycol and mannose. No other monosaccharides tested (galactose and fucose) had any effect on the hydrophobic interaction of bacteria with mannose-specific structures. These results further strengthen the hypothesis that the mannose-specific interaction of Escherichia coli bacteria is, at least in part, mediated by hydrophobic forces.

Adhesiveness↗
PubMed1985

Interaction between human polymorphonuclear leukocytes (PMNL) and bacteria cultivated in aerobic and anaerobic conditions.

A study was performed on one strain of Escherichia coli (E. coli K12D22) and on one strain of Salmonella braenderup (S. braenderup S2828). The physico-chemical surface properties of the bacteria were strongly influenced by oxygen supply, viz. anaerobic growth conditions resulted in increasing of hydrophobicity. Interaction between human polymorphonuclear leukocytes and bacteria, measured as chemiluminescence, was more efficient when bacteria had been cultivated anaerobically than when cultivated aerobically. The results show the importance of the surface hydrophobicity of bacteria in interaction with PMNL, and the role of the growth conditions of bacteria in that process.

Adhesiveness↗
PubMed1985

Erythrocyte enhancement of C3b-mediated phagocytosis by human neutrophils in vitro: a combined effect of the erythrocyte complement receptors CR1 and erythrocyte scavengers to reactive oxygen metabolites (ROM).

Human erythrocyte CR1 receptors have been shown to bind complement-fixing immune complexes and, thus, facilitate their elimination from the circulation. The autotoxic effect of free radicals released from phagocytes during phagocytosis can be alleviated by scavengers like catalase and superoxide dismutase. Erythrocytes are known to contain these antioxidants. This study showed that 74% of opsonized yeast particles adhered to human erythrocytes. No difference was seen between yeast opsonized with C3b and yeast opsonized with both IgG and C3b. This adherence was due to the C3b receptor (CR1), as monoclonal antibodies against the CR1 receptor could abrogate the adherence. The yeast phagocytosis by neutrophils was increased by 15% when yeast-C3b was used, and by 34% when yeast-IgG/C3b was used in the presence of human red blood cells. The increase of phagocytosis was not seen when rat erythrocytes (lacking CR1) were present. The cytochrome c reduction decreased with the presence of human erythrocytes during phagocytosis, indicating a scavenging effect on the superoxide anions. The addition of scavengers or erythrocyte lysate, instead of erythrocytes, enhanced phagocytosis of yeast-IgG/C3b to at least the same extent as the erythrocytes. These observations suggest that human erythrocytes primarily enhance phagocytosis through the scavenging effect of those erythrocytes which are concurrently attached with the prey through its CR1 receptor, and then attached to the PMN.

Complement C3b↗
PubMed1984

Myeloperoxidase reduces the opsonizing activity of immunoglobulin G and complement component C3b.

The effect of myeloperoxidase, hydrogen peroxide (H2O2) and a halide (Cl) on the opsonizing molecules in immunoglobulin G (IgG) and complement factor C3b was assayed. At concentrations of the enzyme (1 microgram/ml) that can be found in the extracellular fluid during inflammation, the myeloperoxidase-H2O2-Cl system inhibited the opsonizing effect of IgG and C3b measured as phagocytic uptake and superoxide generation. The effect was related to the enzymatic peroxidative activity of the protein. The presence of albumin (10 mg/ml) reduced the effect of myeloperoxidase with 10-20%. Taurine, which in the presence of myeloperoxidase-H2O2-Cl forms hydrophilic chloramines, and D-penicillamine, which scavenges HOCl, neutralize the inhibitory effect of myeloperoxidase. This suggests that either hypochlorous acid or lipophilic chloramines may exert its effect by oxidizing free sulphydryl groups exposed on the opsonizing ligands. Since the myeloperoxidase-H2O2-halide system also affects chemotactic factors, leukotrienes, proteinases and membrane receptors, the system may in several ways affect the development of the inflammatory response.

Complement C3b↗
PubMed1984

Chemotaxis of polymorphonuclear leukocytes in response to surface-bound complement-derived chemoattractants generated in situ.

Polymorphonuclear leukocytes (PMNLs) were allowed to migrate on slides with fixed yeast particles dotted about on the surface. Locomotion was quantified by counting the number of yeast particles in association with a PMNL. Yeast particles that differed in their ability to consume hemolytic complement differed also in their ability to generate chemoattractants. Addition of a complement source to yeast particles able to activate the complement system resulted in a chemotactic response, as well as when fluid-phase attractants were removed prior to the measurement of PMNL chemotaxis, indicating that the chemoattractants generated were absorbed to the surface. Using an immunofluorescence technique, it was found that complement factor 5 coated a circular area around each yeast particle, provided that the particles were able to activate the complement system.

Chemotactic Factors↗
PubMed1984

Effect of polyethyleneglycols (PEG 600 and PEG 6000) and bovine serum albumin on myeloperoxidase-mediated release of [3H]-serotonin from rat peritoneal mast cells in vitro.

Rat peritoneal mast cells in vitro released [3H]-serotonin in the presence of halide (I-), myeloperoxidase (MPO), and a H2O2-generating system. The degranulation was partly inhibited with low concentrations of bovine serum albumin (BSA; 0.1-1% w/v), or polyethyleneglycols (PEG 600 or PEG 6000, 0.1% w/v). Furthermore, PEG 600 and PEG 6000 enhanced the stabilization achieved with 0.1% BSA. The results may provide a new aspect on antigenicity of PEG-modified allergens, and on mast-cell response at an inflammatory site.

Animals↗
PubMed1984

Metabolic activation of human neutrophils by fluid-phase and particle-bound ligands.

The ability of particle-bound and fluid-phase ligands (IgG, C3b, and ConA) to induce metabolic activation in cytochalasin B-treated human neutrophils was studied. Different activation mechanisms of the neutrophils are proposed, since the activation of cytochalasin B-treated neutrophils is not dependent on whether or not the ligands are particle-bound but not on the nature of ligand per se.

Complement C3b↗
PubMed1984

Comparison between luminol- and lucigenindependent chemiluminescence of polymorphonuclear leukocytes.

Phorbolmyristate acetate (PMA) induced both a luminol- and a lucigenindependent chemiluminescence response in normal polymorphonuclear leukocytes (PMNL). PMNL isolated from a patient with a myeloperoxidase (MPO)-deficiency were found to produce almost no luminol-dependent chemiluminescence. The lucigenin-dependent chemiluminescence response was, however, found not to differ between normal and MPO-deficient cells. From these results it was concluded that the luminol- and the lucigenin-dependent chemiluminescence differed in the dependence of MPO. Results obtained with cell-free MPO-H2O2- and superoxide anion producing systems further supported this conclusion.

Acridines↗
PubMed1984

Activation of polymorphonuclear leukocytes by salmonella.

The interaction of polymorphonuclear leukocytes (PMN) with salmonella, as studied by chemiluminescence and phagocytosis, was very different for a number of clinical isolates. Particularly bacteria in the serogroups C1 and E4 deviated from other Salmonella. The differences were observed in the rate of activation, peak value, duration of the chemiluminescence, and in the extent of association and ingestion as studied microscopically. Old laboratory S-strains such as Salmonella typhimurium 395 MS and S. minnesota S99 , which did not associate with the PMN, showed little activation of the PMN, whereas their phagocytosis-sensitive R-mutants induced rapid activation, high peak values, and short duration of the chemiluminescence. Certain isolates belonging to the C1/E4 group induced intermediate types of reactions. The kinetics of the activation was related to the physicochemical surface properties of the bacteria. Heating the bacteria at 70 degrees C for 45 min enhanced the activation of PMN by the S-type strains conspicuously but in different ways, whereas that of R-mutants was delayed. Different clinical isolates of salmonella have shown different physico-chemical surfaces, liability to phagocytosis by PMNs and different degrees of eliciting inflammatory mediators from PMNs in vitro. The results indicate that the C1/E4 group of Salmonella has pathogenicity mechanisms different from most salmonellae.

Hot Temperature↗
PubMed1984

Intra- and extracellular events in luminol-dependent chemiluminescence of polymorphonuclear leukocytes.

When polymorphonuclear leukocytes (PMNL) and soluble or particulate matter interact, the cells produce chemiluminescence. Luminol-dependent light emission from PMNL is linked to the myeloperoxidase (MPO)-H2O2 system. Light emission from a cell-free MPO-H2O2 system was found to be totally inhibited by human serum albumin (HSA), and since HSA is a large molecular protein that does not readily gain access to intracellular sites of PMNL, it could be used to determine the importance of extra- and intracellular events in PMNL chemiluminescence. In studies with cells from an MPO-deficient patient, we found that HSA inhibited more than 90% of extracellularly produced chemiluminescence. The chemotactic peptide formylmethionyl-leucyl-phenylalanine induced a two-peak chemiluminescence response in normal PMNL, and addition of HSA reduced the first peak, whereas the second peak was unaffected. This result indicated that the first peak was a result of extracellular reactions and the second peak was a result of intracellular reactions of the MPO-H2O2 system. Most of the phorbol myristate acetate-induced response in normal PMNL was due to intracellular events. Furthermore, chemiluminescence of intracellular origin seems to be limited not by generation of oxidative metabolites but by diffusion of luminol into the cells.

Humans↗
PubMed1984

Histamine release from mast cells during phagocytosis and interaction with activated neutrophils.

Histamine release from rat peritoneal mast cells was evaluated during interaction with IgG, C3b-bi and Concanavalin A-opsonized yeast particles and activated neutrophils. In contrast to others we could show no phagocytic uptake of yeast particles attaching to Fc, or Concanavalin A receptors on the mast cell. Attached yeast particles opsonized with C3b/bi were also poorly ingested (less than 10% of the attached particles.) Neither could we detect any significant histamine release. If, however, neutrophils were added to the mast cell-yeast particle complex, histamine release was induced particularly in the presence of Concanavalin A-yeast. We furthermore showed that phorbol myristate acetate-activated neutrophils and eosinophils initiated mast cell degranulation and histamine release. This release is not dependent on myeloperoxidase, but on other oxidative metabolites, since myeloperoxidase-deficient neutrophils also induce histamine release. These experiments show that mast cells exposed to immune complexes and activated neutrophils or eosinophils may augment the inflammatory response.

Eosinophils↗
PubMed1984

Myeloperoxidase modulates the phagocytic activity of polymorphonuclear neutrophil leukocytes. Studies with cells from a myeloperoxidase-deficient patient.

Patients lacking the primary granulae enzyme, myeloperoxidase (MPO), do not usually show any increased susceptibility to infection or altered inflammatory response, in contrast to several other biochemical defects in polymorphonuclear neutrophils. We have now evaluated the role of MPO on phagocyte function in a patient with complete MPO deficiency suffering from generalized pustular psoriasis. We found that the MPO-deficient neutrophils showed enhanced phagocytosis (greater than 200% of normal) of IgG- and C3b-opsonized yeast particles and prolonged N-formylmethionyl-leucyl-phenylaline-mediated stimulation of superoxide production. When purified human MPO was added to normal neutrophils during cell adhesion, their Fc- and C3b-mediated phagocytosis was reduced without affecting cell viability. 1 microgram/ml of MPO reduced the Fc and C3b phagocytosis to 47 and 65%, respectively, whereas 10 micrograms/ml reduced the activity to 20 and 54%. Both attachment and ingestion were reduced to a similar extent, indicating that MPO affected the receptor function per se. When MPO was added to the hyperactive MPO-deficient cells, phagocytosis was reduced more rapidly. Catalase, azide, and methionine eliminated the inhibitory effect, and catalase and methionine, in fact, enhanced the phagocytic activity of adherent neutrophils. These data indicate that, apart from being a potent antimicrobial system, the oxidizing activity of the MPO-H2O2-halide system may modulate the inflammatory response by impairing certain receptor-mediated recognition mechanisms of phagocytic cells, which otherwise could elicit inflammatory reactions and tissue injury.

Complement C3b↗
PubMed1983

A quantitative microassay for leukocyte chemotaxis, using a microscopic slide system with complement-activating yeast particles as gradient source.

A simple quantitative microassay was developed for studying polymorphonuclear leukocyte (PMNL) chemotaxis under conditions where the number of available cells is a limiting factor, e.g., pustules, neutropenia, small children and cerebrospinal fluid. PMNL suspensions are placed on glass slides to which fluorescein-labeled yeast particles have been fixed. After adherence, normal human serum is added to the slides. Owing to complement activation, a chemotactic gradient which attracts the adherent PMNL is formed around the yeast particles. The number of PMNL-associated yeast particles in the presence of normal serum is scored, and compared with cells migrating in the presence of inactivated serum or in the absence of serum. A locomotory index is calculated as the number of yeast particles associated with PMNL divided by the total number of yeast particles.

Blood Physiological Phenomena↗
PubMed1983

Hydrophobic interaction between DNP-HSA and different tissue structures in vivo assessed by indirect immunofluorescence microscopy.

Circulating dinitrophenylated human serum albumin (DNP-HSA) was shown by indirect immunofluorescence microscopy to adhere to non-parenchymal liver cells and capillaries of striated muscle in mice. The DNP-HSA at these sites could be removed by surface-tension-lowering agents such as Triton X-100 and ethylene glycol. The adherence of DNP-HSA to white blood cells in vitro was inhibited in the presence of 0.3 M ethylene glycol. The findings support the hypothesis that hydrophobic interaction with different tissue structures may be important for the fate of circulating antigens and immune complexes. Indirect immunofluorescence microscopy offers a simple means of checking the role of hydrophobic bonding for the tissue adherence of various substances in vivo.

Animals↗
PubMed1983

Lateral diffusion of wheat germ agglutinin-labeled glycoconjugates in the membrane of differentiating HL-60 and U-937 cells assessed with fluorescence recovery after photobleaching (FRAP).

The promyelocytic leukemia cell line HL-60 and the histiocytic cell line U-937 were grown in suspension culture. They were induced to differentiate during 5-d cultivation in the presence of dimethylsulfoxide (DMSO; 1.3% w/v) or phorbol-12-myristate-acetate (PMA; 10(-7) M), which yields granulocyte- and macrophage-like cells, respectively. Differentiation was evidenced by increased capacity to recognize and phagocytize IgG- or complement-coated yeast particles. Aliquots taken from the cultures with and without DMSO (or PMA) were spun down directly on glass microscope slides, washed, labeled with fluoresceinated wheat germ agglutinin (WGA), and directly examined at room temperature for the rate of fluorescence recovery after photobleaching (FRAP). It was found that cultivation of the HL-60 and the U-937 cells in the presence of DMSO, which yields granulocyte-like cells, reduced the average value of lateral diffusion coefficient D (X 10(10] from 1.72 +/- 0.13 cm2s-1 to 0.97 +/- 0.13 cm2s-1 and from 1.77 +/- 0.11 cm2s-1 to 0.82 +/- 0.13 cm2s-1, respectively. U-937 cells grown with PMA also showed a reduction of D(X 10(10] to 0.88 +/- 0.10 cm2s-1. There was a larger immobile fraction of fluorescence in the HL-60 cells than in the U-937 cells, viz., 70-80% compared to 10-50%. The total number of binding sites for WGA was not altered, but the surface density changed, since the HL-60 and the U-937 cells became smaller and larger, respectively, when grown in the presence of DMSO. It is concluded that differentiation reduces the average lateral mobility of the WGA-binding membrane component by a factor around 2.

Cell Differentiation↗
PubMed1983

Physicochemical surface properties and phagocytosis by polymorphonuclear leucocytes of different serogroups of Salmonella.

Salmonella isolates belonging to different serogroups have been analysed with respect to physicochemical surface properties and interaction with human polymorphonuclear granulocytes (PMNs). Most (22/34) recent isolates of the different serotypes showed hydrophilic surface properties and little if any negative charge accompanied by resistance to phagocytosis by PMN similar to the old laboratory S strains Salmonella typhimurium 395MS and Salmonella minnesota S99 (main group). However, all isolates belonging to the serogroups C1 (5 isolates), E4 (2), O43 (1), and one out of three E1 isolates (C1/E4 group) differed from the main group. In aqueous biphasic partition in dextran-polyethyleneglycol (PEG) systems the bacteria in the main group accumulated in the PEG-rich phase to 55-97%, those in the C1/E4 group to less than 10%, and R-mutants only to 1-2%. The bacteria in the C1/E4 group displayed a negative surface charge and a susceptibility to phagocytosis by PMNs that were greater than those for strains in the main group but much lower than those shown by the R-mutants. Bacteria belonging to serogroup C1 also displayed a significant susceptibility to hydrophobic interaction. The results are discussed in relation to the pathogenicity of salmonella.

Cell Membrane↗
PubMed1983

Physico-chemical surface properties of Shigella sonnei.

In partition in two-phase systems as well as in hydrophobic and ion exchange chromatography a number of Sh. sonnei isolates with different phage patterns showed similar physico-chemical surface properties. All the isolates displayed hydrophobicity and a small negative charge. In this way the shigellae were different from salmonella S-strains and E. coli strains associated with infantile diarrhoea which have shown hydrophilic properties and nearly no charge. They were also different from E. coli strains with typical K-antigen often grown from patients with septicemia and upper urinary tract infection, which have shown hydrophilic properties and a great negative charge. However, the Sh. sonnei isolates were similar to E. coli strains belonging to certain serogroups which have been grown from patients with dysentery-like diseases. The results indicate that physico-chemical surface properties are related among enterobacteria belonging to different genera which have been grown from similar types of infections.

Adhesiveness↗