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Biomedical subjects

O Stendahl

Publications and source records attributed to O Stendahl.

At least 145 records · Page 8Linked to original sources
PubMed1977

The tendency of smooth and rough Salmonella typhimurium bacteria and lipopolysaccharide to hydrophobic and ionic interaction, as studied in aqueous polymer two-phase systems.

In aqueous two-phase system, the partition of bacteria and lipopolysaccharide from a rough (R) strain (Rd-mutant) of Salmonella typhimurium is influenced by polymers with covalently linked hydrophobic groups indicating hydrophobic structures accessible at the cell surface. Furthermore, the partition of the R bacteria is influenced by a number of inorganic positive and negative ions, presumably as a consequence of interaction with negatively charged surface structures. In contrast, smooth (S) bacteria and lipopolysaccharide from the parent strain do not seem to participate in either hydrophobic or charge interaction indicating extensive hydrophilicity without charge. Thus, the S-specific polysaccharide side chain of S. typhimurium might serve the purpose of blindfolding aspecific host defence mechanisms dependent on hydrophobicity and charge. On the contrary, the R bacteria and R lipopolysaccharide have physico-chemical properties which predispose to interaction with several types of cells, organelles and molecules.

Dextrans↗
PubMed1977

Association of some enterobacteria with the intestinal mucosa of mouse in relation to their partition in aqueous polymer two-phase systems.

The association of enterobacteria with mouse intestinal mucosa has been investigated by pumping heat-killed, radioactively-labelled bacteria through the gut lumen in vitro. Approximately 20 cm of the small intestine proximal to the ileo-caecal valve was rinsed, excised and maintained in an organ bath. By using two different bacteria labelled with different radioactive isotopes, the relative association of the two bacterial pumped through the same piece of gut was determined. Cross-labelling showed that choice of isotope did not affect the association. Salmonella typhimurium 395 MR10 was used as reference and the other bacteria investigated related to it. S. typhimurium MR10 and Escherichia coli O 14 K7, which are relatively lipophilic, showed greater association than S. typhimurium 395 MS and E. coli O 111 K58, which are more hydrophilic. Prolonged incubation of bacteria with the length of intestine in vitro leading to damage of the brush border of the mucosal epithelium enhanced the association of the bacteria. These data suggest that similar physico-chemical surface properies govern the association certain enterobacteria to the intestinal mucosa as in phagocytosis with professional phagocytes.

Acetylglucosaminidase↗
PubMed1977

Surface-charge characteristics of smooth and rough Salmonella typhimurium bacteria determined by aqueous two-phase partitioning and free zones electrophoresis.

Aqueous biphasic partitioning of Salmonella typhimurium S and R bacteria in a system containing 6.2 per cent (w/w) dextran 500 and 4.4 per cent (w/w) poly(ethyleneglycol) 6000 (PEG) was similar to the partition of the corresponding surface lipopolysaccharide (LPS). Further partition analysis with charged PEG showed that S bacteria and their LPS exposed very little charge, whereas R bacteria and their LPS showed a conspicuous negative charge at neutral pH. Free zone electrophoresis also indicated that the S bacteria have a much lower surface charge density than the R bacteria and accordingly a different surface structure. Thus, the physico-chemical properties of the bacterial surface seem to be determined to a great extent by the characteristics of the cell surface LPS.

Cell Wall↗
PubMed1977

Characteristics of the phagocytic process assessed by Coulter Counter.

The phagocytosis in suspensions of heat-killed yeast cells, Saccharomyces cerevisiae, by human polymorphonuclear leucocytes was studied in vitro by means of an electronic particle counter, the Coulter Counter, and a 100-channel pulse-height analyzer, the Channelyzer. The two cell populations were separated from each other electronically by the Channelyzer. Phagocytosis was recorded as disappearence of yeast cells. Concomitantly, aggregation and swelling of the PMN-cells were observed, which increased with the concentration of the prey. The process could be inhibited by cytochalasin B and iodoacetamide. With the latter inhibitor, the analysis of the kinetics showed that ingestion, but not adhesion, was affected. The ingestion of yeast cells was augmented on increase of the initial ratio between the number of yeast and PMN cells to around 5:1, but was then reduced on further increase. A ratio of 2:1 and a reaction time of 30 min seemed suitable for studying the phagocytic process. First-order kinetics were obeyed under these circumstances.

Blood Cell Count↗
PubMed1977

Liability to hydrophobic and charge interaction of smooth Salmonella typhimurium 395 MS sensitized with anti-MS immunoglobulin G and complement.

Sensitization of smooth Salmonella typhimurium 395 MS bacteria with hyper-immune anti-MS immunoglobulin G (IgG) antibodies increased the liability to hydrophobic interaction as assessed by the affinity for a column of Octyl-Sepharose. After sensitization, the material originally eluted with 1 M (NH4)SO4 in a 0.01 M phosphate buffer (pH 6.8) was not desorbed until the ionic strength was reduced to nil, and 0.1% (vol/vol) Triton X-100 in the 0.01 M phosphate buffer was used as eluant. Furthermore, by including positively charged bis-trimethylamino-polyethylene glycol (PEG) or negatively charged bis-sulfoamino-PEG in an aqueous two-phase system of dextran T500 and PEG 6000, the partition of the IgG-sensitized bacteria was affected by either of the polymers, whereas that of the parent bacteria was not. The hydrophobic effect of IgG binding was enhanced by complement. With heat-inactivated complement, the effect of IgG was diminished. The F(ab')2 fragment showed a much lower capacity to promote a hydrophobic interaction than the complete IgG molecule.

Antibodies, Bacterial↗
PubMed1977

Physiochemical consequences of opsonization of Salmonella typhimurium with hyperimmune IgG and complement.

Partition in an aqueous, two-polymer phase system containing dextran and polyethylene glycol was employed to investigate the physico-chemical changes inflicted upon the cell surface of a smooth strain of Salmonella typhimurium by the binding of antibody IgG and complement. The minimum antibody concentration for increased phagocytosis in vitro was approximately the same as that for a significant change in two-phase partition, ca 8000 mol/bacterium, whereas a lower concentration, less than 4000 mol/bacterium, was sufficient to increase clearance in vivo. After pepsin digestion of IgG, larger quantities, ca 35,000 mol/bacterium, was required for opsonization and to influence two-phase partition. Addition of normal rabbit or guinea-pig serum to bacteria sensitized with a low concentration of antibody IgG conspicuously enhanced phagocytosis and affinity for the dextran-rich phase. The results show that binding of 8000 IgG antibody molecules or more to smooth S. typhimurium generates physicochemical changes of the bacterial surface which from studies on S leads to R mutations are known to correlate with hydrophobicity, negative charge and phagocytosis. Such results support the view that one important function of IgG antibody and complement is to decrease the hydrophilic properties of the bacteria which is thought to be a prerequisite for phagocytosis.

Binding Sites, Antibody↗
PubMed1977

Physicochemical consequences of opsonization: perturbation of liposomal membranes by Salmonella typhimurium 395 MS opsonized with IgG antibodies.

When phagocytosis-resistant Salmonella typhimurium 395 MS bacteria sensitized with anti-MS IgG antibodies were incubated with liposomes composed of phosphatidylcholine, cholesterol, and dicetylphosphate, a previously sequestered liposomal marker (4-methylumbelliferylphosphate) was released. Unsensitized or F(ab')2-sensitized bacteria had no such effect. This perturbation was neither dependent upon negatively charged dicetylphosphate nor upon cholesterol. It was further evident that palmitoyl-poly(ethyleneglycol) caused release of the trapped marker in a similar way as sensitized bacteria. These findings demonstrate a similarity between sensitized bacteria and a hydrophobic probe and lend support to the hypothesis that the perturbation was brought about by hydrophobic interaction. The observations indicate that liposomes, like phagocytes, possess "receptor sites" for the activated part of IgG and raise the possibility that phagocytic effectors can operate in a relatively nonspecific manner.

Antibodies, Bacterial↗
PubMed1976

Function of granulocytes with deficient myeloperoxidase-mediated iodination in a patient with generalized pustular psoriasis.

The granulocytes of a patient with generalized pustular psoriasis (GPP) were found to have impaired ability to fix iodine after ingestion of yeast particles. Since hexose monophosphate shunt (HMS) activity was increased and the contents of 3 other lysosomal enzymes, beta-glucuronidase, N-acetyl-beta-glucosaminidase and lysozyme, were within normal range, the impaired iodination appeared to be due to a selective defect of myeloperoxidase (MPO) activity within the phagocytic cells. The deficient iodination was accompanied by a decreased intracellular killing of E. coli and C. albicans. Since hexose monophosphate shunt activity was enhanced and azide and cyanide inhibited the intracellular killing of E. coli only moderately, the patient's granulocytes may possess azide- and cyanide-resistant, MPO-independant microbicidal systems coupled to the oxidative metabolism. Assessment of granulocyte iodination and enzyme contents of the relatives of the patient revealed no hereditary transmission. Since GPP is characterized by the development of subcorneal pustules containing granulocytes, the MPO-deficiency may be the cause of or enhance the development of the disease.

Azides↗
PubMed1976

Phagocytic activity of polymorphonuclear leukocytes in generalized pustular psoriasis.

The phagocytic activity of polymorphonuclear leukocytes from 10 patients suffering from generalized pustular psoriasis (GPP) has been studied. In all patients intracellular iodination capacity was measured, and 6 were studied regarding hexose monophosphate shunt activity (HMS) and bactericidal capacity. In 2 patients leukocytes from pustules were tested by the iodination reaction. Sera from 7 patients were incubated with normal leukocytes in a bactericidal test to evaluate the opsonizing capacity, which was found to be normal. Leukocytes from patients with GPP after 120 min of incubation with bacteria exhibited significantly impaired lethality compared with the controls, but no significant difference was found after 60 min. Iodination capacity and HMS activity were normal in all patients except in one, who was found to be deficient in myeloperoxidase. The possible significance of the impaired lethability of bacteria in the pathogenesis of GPP is discussed.

Adult↗
PubMed1975

On the physical-chemical effect of colostral antibody binding to Escherichia coli O 86.

Sensitization of Escherichia coli O 86 with colostrum or purified colostral sIgA antibody produces a physical-chemical change of the bacterial surface detectable as a change in partition in dextran-polyethylene glycol polymer two-phase systems. Sensitization with colostrum or sIgA reduces affinity for the dextran-rich phase. In contrast immune serum, IgG and complement increase the affinity for that phase. The results are compatible with the hypothesis that hydrophilic particles, e.g. certain strains of bacteria, are less liable to attachment to and phagocytosis by animal cells than hydrophobic particles, e.g. other bacterial strains. Sensitization with secretory IgA enhances the hydrophilicity thereby making possible an escape mechanism operating at the mucosal surfaces.

ABO Blood-Group System↗
PubMed1975

The function of polymorphonuclear leukocytes after surgical trauma.

The effect of surgical trauma on human polymorphonuclear leukocytes (PMN) was studied by measuring the hexosemonophosphate shunt (HMS) activity and myeloperoxidase mediated iodination during phagocytosis. Patients submitted to elective general surgery showed normal iodination capacity and normal HMS activity in their PMN cells postoperatively. This implies that postoperative infectious complications are not caused or promoted by defective PMN cell function. Iodination was found significantly (p less than 0.05) impaired in phagocytosing PMN cells from burned patients whereas it was found normal in traumatic and septic conditions. No direct relation between extent of injury and degree of leukocyte impairment was found. HMS activity remained normal in burned patients suggesting that the impaired iodination might depend on a defective mobilization of lysosomal enzymes.

Adolescent↗
PubMed1974

Influence of hyperimmune immunoglobulin G on the physicochemical properties of the surface of Salmonella typhimurium 395 MS in relation to interaction with phagocytic cells.

Partition in an aqueous, two-polymer phase system containing dextran and polyethylene glycol was employed to investigate the physicochemical changes inflicted by the presence of immunoglobulin G (IgG) antibodies on the cell surface of a smooth strain of Salmonella typhimurium. Adding increasing amounts of anti-Salmonella IgG to the bacteria decreased the affinity for the polyethylene glycol-rich top phase, with a concomitant increase in in vivo clearance and in vitro phagocytosis by rabbit polymorphonuclear cells. Similarly, S --> R mutations in the same S. typhimurium strain decrease the affinity for the top phase and increase the liability to phagocytosis. The limiting antibody concentration to demonstrate increase of in vitro phagocytosis was approximately the same as that to produce a significant effect in the phase system, whereas lower concentrations were needed to increase the in vivo clearance. The results show that adsorption of IgG antibodies to bacteria brings about physicochemical changes of the cell surface which seem to promote the phagocytosis by polymorphonuclear cells and uptake in the reticuloendothelial system.

Animals↗
PubMed1973

Characterization of mutants of Salmonella typhimurium by counter-current distribution in an aqueous two-polymer phase system.

An aqueous, two-polymer phase system was employed in an attempt to separate and characterize a series of R mutants, derived from Salmonella typhimurium 395 MS, with differing lengths of lipopolysaccharide chains on their surfaces. R mutants with varying degrees of virulence and phagocytic resistance were unresolved in this system. However, the smooth MS bacteria were clearly separated from the rough cells and showed a high affinity for the polyethylene glycol-rich top phase. A uridine 5'-diphosphate-gal-4-epimeraseless mutant, phenotypically in R or S form depending on the growth medium, partitioned as the R mutants and S bacteria, respectively. These results demonstrate the great influence of long polysaccharide chains on the physicochemical properties of the cell surface.

Bacteriological Techniques↗
PubMed1973

Partition of Salmonella typhimurium in a two-polymer acqueous phase system in relation to liability to phagocytosis.

Analysis of the partition in a two-polymer phase system of Salmonella typhimurium R mutants with different susceptibility to phagocytosis distinguished between the mutants. Close to 80% of the R mutants least resistant to phagocytosis accumulated in the dextran-rich phase, whereas more phagocytosis-resistant mutants showed higher affinity for the interface and the polyethylene glycol-rich top phase. By growing the uridine diphosphate (pyro)-gal-4-epimeraseless mutant LT2-M1 in the presence of d-galactose for different periods of time, two well-defined peaks were obtained in counter-current distribution analysis with an aqueous two-polymer phase system revealing a heterogeneous population in the culture. One peak was located at a site characteristic of R bacteria, the other at the site of S bacteria. As growth proceeded, more bacteria transferred from the R-type to the S-type peak. Within each peak, a gradual increase in resistance to phagocytosis by rabbit polymorphonuclear cells occurred with increasing length of growth in d-galactose.

Countercurrent Distribution↗