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C Dahlgren

Publications and source records attributed to C Dahlgren.

At least 145 records · Page 8Linked to original sources
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

Effect of hyaluronic acid on polymorphonuclear leucocyte cell surface properties.

Polymorphonuclear leucocytes (PMNL) were incubated with hyaluronic acid (HA), and then characterized with respect to their surface properties. Surface analysis was achieved by partitioning in systems of dextran and poly(ethylenglycol) (PEG), with part of the PEG exchanged for positively charged trimethylamino-PEG or hydrophobic PEG-palmitate. The results indicate that HA caused increased exposure of hydrophobic and of negatively charged groups on the PMNL surface. These findings may be relevant for the biological effects of HA on PMNL function and cell-cell interactions.

Cell Communication↗
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↗
PubMed1981

Phagocytosis and hydrophobicity: a method of calculating contact angles based on the diameter of sessile drops.

The correlation between the contact angle and degree of phagocytosis of different yeast particles has been investigated. To facilitate the estimation of the contact angle, we have tested the hypothesis that the shape of a small liquid drop put on a flat surface is that of a truncated sphere. By making this approximation it is possible to calculate the contact angle, i.e. the tangent to the drop in the 3-phase liquid/solid/air meeting point, by measuring the drop diameter. Known volumes of saline were put on different surfaces and the diameters of the drops were measured from above. Calculation of the contact angle with drops of different volumes, and comparison between expected and measured height of 10 microl drops, indicated that the assumption that the shape of a drop is that of a truncated sphere is valid. Monolayers of leukocytes was shown to give rise to a contact angle of 17.9 degrees. Particles with a lower contact angle than the phagocytic cells resisted phagocytosis, but opsonization of the particles with normal human serum rendered them susceptible to phagocytosis, conferring a higher contact angle than that of the phagocytic cells.

Humans↗
PubMed1981

Deactivation of leucocyte chemotaxis in vivo. Locomotion of cells isolated from a patient with meningococcal meningitis.

This report concerns the properties of polymorphonuclear leucocytes isolated from a patient with meningococcal meningitis. No differences in phagocytic capacity and random locomotion between the patient's polymorphonuclear leucocytes and normal PMNL were found, but by using activated normal human serum as chemo-attractant it was found that PMNL isolated from the cerebrospinal fluid had lost their ability to respond chemotactically. The deactivation was found to be accompanied by surface property changes of the cells.

Aged↗
PubMed1980

Modulation of polymorphonuclear leukocyte locomotion by synthetic amphiphiles: effect of saturated fatty acid esters (C2-C18) of poly(ethyleneglycol) 6000.

The capacity of synthetic amphiphiles poly(ethyleneglycol) 6000 (PEG) esterified with saturated fatty acids (C2-C18), to modify polymorphonuclear leukocyte (PMNL) locomotion has been investigated. It was noticed that PEG-myristate (M-PEG; C14) stimulated the random locomotion of PMNL populations in concentrations up to about 1 g/L. The esters with shorter aliphatic chains had negligible effects, whereas those with longer chains, PEG-palmitate (P-PEG; C16) and PEG-stearate (S-PEG; C18) reduced the locomotion, irrespectively of concentration. The ability of the PMNL to be stimulated by an attractant liberated from normal human serum was slightly impaired by M-PEG, but not by P-PEG. The response to M-PEG of individual PMNL was heterogeneous in that some cells were stimulated and others were inhibited. However, the average result was a reduction of the motility. This indicates that methods used for the study of the locomotion of cell populations may not always reflect the average behavior of the whole population. It was also concluded that the different effects of M-PEG and P-PEG owed to dissimilar effects on the membrane structure of the PMNL since (1) M-PEG perturbated the PMNL membrane more than P-PEG, as assayed by the release of superoxide anion (O2-), although the binding was smaller, and (2) M-PEG and P-PEG increased and decreased the membrane fluidity, respectively, as measured with fluorescent bleaching and recovery after bleaching of labeled PMNL. The results indicate a subtle coupling between membrane structure and PMNL locomotion.

Cell Membrane↗
PubMed1980

Modulation of polymorphonuclear leukocyte locomotion by synthetic amphiphiles.

The effect of synthetic amphiphiles, poly(ethyleneglycol) 6000 (PEG) esterified with saturated fatty acids (C2-C18), on the locomotion of polymorphonuclear leucocytes (PMNL) has been investigated. It was noticed that PEG-myristate (M-PEG; C14) stimulated the random locomotion of PMNL populations in concentrations up to about 1 g/l. By contrast, the esters with shorter aliphatic chains had negligible effects and those with longer chains, PEG-palmitate (P-PEG; C16) and PEG-stearate (S-PEG; C18) reduced the locomotion, irrespectively of concentration. The ability of the PMNL to be stimulated by an attractant liberated from normal human serum was slightly impaired with M-PEG, but not with P-PEG. The response to M-PEG of individual PMNL was heterogeneous in that some cells were stimulated and others were inhibited, but the average result was a reduction of the motility. This indicates that methods used for the study of the locomotion of cell populations do not always reproduce the true behaviour of the whole population, but rather of a selected subpopulation. It was also concluded that the different effects of M-PEG and P-PEG were probably not due to phagocytosis or selective binding of either substance, but rather due to dissimilar effects on the membrane structure of the PMNL, since (i) M-PEG perturbated the PMNL membrane more than P-PEG, as assayed by the release of superoxide anion (O2-) although the binding was smaller, and (ii) M-PEG and P-PEG increased and decreased the membrane fluidity, respectively, as measured with fluorescence bleaching and recovery after bleaching of labeled PMNL. The results indicate a subtle coupling between membrane structure and PMNL locomotion.

Cell Membrane↗
PubMed1979

Characteristics of individual polymorphonuclear leucocyte motility obtained with a new opto-electronic method.

An opto-electronic device has been used for a quantitative assessment of the motility of individual polymorphonuclear leucocytes (PMNL) adhering to a glass cover slip. One of the oculars in a phase contrast microscope is provided with a mini-array of 32 x 32 light-sensitive elements. These are connected to an electronic unit, capable of recording the number of light-intensity changes on each element and of visualizing the path of a cell on an oscilloscope screen, as a pattern of dots. The results clearly show that individual PMNL respond differently to environmental conditions; for instance, (i) raising the temperature increased the motility of cells to a maximum at around 39 degrees C and lowering the temperature from 42 degrees C restored their peak motility, (ii) protein was required at attachment depending on the temperature at attachment, (iii) endotoxin-activated normal human serum affected more drastically cells with a low initial motility and cytochalasin B more adversely influenced cells with a high initial motility, (iv) phagocytosis of yeast cells reduced the percentage of motile cells, which was more pronounced if the PMNL were washed before the motility measurement. The average motility of the PMNL was also diminished, although individual PMNL retained normal activity after ingestion of one or more yeast cells.

Animals↗
PubMed1978

The inhibition of polymorphonuclear leukocyte cytotoxicity by dapsone. A possible mechanism in the treatment of dermatitis herpetiformis.

The effect of the sulfone compound 4,4'-diaminodiphenyl sulfone (dapsone) on normal human polymorphonuclear leukocytes (PMNL) has been investigated in vitro. The drug has a dramatically beneficial effect in dermatitis herpetiformis in which the PMNL and immune complexes has been stressed to be of importance for the development of the skin lesions. Pruritus disappears and the inflammatory eruptions clear within a few days of starting therapy. The effect of dapsone has been evaluated on the different stages of phagocytosis. Using dapsone concentrations (1-30 mug/ml) comparable with those found after therapeutic doses, we have found that the drug interferes primarily with the myeloperoxidase (MPO)-H(2)O(2)-halide-mediated cytotoxic system in the PMNL. No effect was observed on random locomotion, chemotaxis, phagocytic ingestion, oxidative metabolism, or the release of lysosomal enzymes. Kinetic studies in a cell-free system with purified MPO revealed a competitive type of inhibition using varying concentrations of NaI. Furthermore, the inhibition resulted in reduced candidicidal activity during phagocytosis of Candida albicans, and reduced cytotoxicity to adjacent mammalian cells measured as the (51)Cr release from virus-induced lymphoma cells. Because the MPO-H(2)O(2)-halide system not only fulfills the antimicrobial activity but is suggested to be a modulator of the inflammatory reaction as well, the action of dapsone in dermatitis herpetiformis may in part be explained by its effect on this system.

Adolescent↗
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↗
PubMedDate not supplied

The phagocyte chemiluminescence paradox: luminol can act as an inhibitor of neutrophil NADPH-oxidase activity.

The chemiluminescence system amplified by luminol or isoluminol is a sensitive and widely used method for determination of respiratory burst products generated by the NADPH-oxidase in phagocytes. The present study shows that luminol, but not isoluminol, can inhibit the release of oxygen metabolites generated by human neutrophil NADPH-oxidase. The difference in structure between luminol and isoluminol (rendering luminol more lipophilic than isoluminol, and thereby membrane-permeable), is suggested to determine indirectly whether or not the molecule is inhibitory. Luminol was shown to have an increased inhibitory effect after preincubation of neutrophils on a surface of aggregated IgG, suggesting that the cells can be transferred from a 'luminol-insensitive' to a 'luminol-sensitive' state. Since luminol had no inhibitory effect in a cell-free NADPH-oxidase system, it is likely that it interferes with the signal transduction pathway, leading to assembly and/or activation of the oxidase. As a consequence of the present results, showing that luminol but not isoluminol can inhibit NADPH-oxidase activity, we suggest that isoluminol is used in future studies of superoxide anion release from phagocytes.

Cell-Free System↗
PubMedDate not supplied

Analysis of luminol-dependent chemiluminescence from granule depleted neutrophil cytoplasts reveals two different light-emitting mechanisms.

When neutrophil cytoplasts (granule-free vesicles of cytoplasm enclosed by plasmalemma) were exposed to the chemotactic peptide formylmethionyl-leucyl-phenylalanine, no luminol-dependent chemiluminescence was detected, despite a pronounced production of superoxide anions and hydrogen peroxide. Addition of purified myeloperoxidase (MPO) or human serum albumin (HSA) to the cytoplasts before the stimulus resulted in a chemiluminescence response. In contrast to the bimodal response obtained from normal PMNL, only a single peak of chemiluminescence was obtained from the cytoplasts responding to the peptide. The time-course of the response obtained in the presence of albumin was more prolonged than the response obtained in the presence of MPO. Furthermore, the involvement of different oxidative metabolites in the MPO and the HSA systems, respectively, was demonstrated by the accumulated chemiluminescence effect obtained when MPO, but not HSA, was introduced in the measuring system after FMLP addition. From these results it can be concluded that there are at least two different light-generating mechanisms in FMLP-induced luminol-dependent chemiluminescence of neutrophil cytoplasts. One of these is dependent on myeloperoxidase and possibly related to the myeloperoxidase-hydrogen peroxide reaction, whereas the other one is hydrogen peroxide independent.

Adult↗
PubMedDate not supplied

Luminol-amplified chemiluminescence activity in human monocytes: a comparison with the activity induced in granulocytes.

The characteristics of the luminol-amplified chemiluminescence (CL) induced in mononuclear phagocytes interacting with PMA, FMLP or ionomycin were determined. Azide reduced the CL activity by more than 80%, while superoxide dismutase and catalase had minor effect on the monocyte CL response. The sensitivity of the monocyte CL response, to the addition of extra peroxidase differed depending on the stimulus used. Furthermore, no direct correlation was obtained between the CL response and superoxide anion or hydrogen peroxide production. In comparison with the response in granulocytes, minor quantitative differences were observed. The mechanism for the light-generating reaction, seems to be the same in both cell types.

Adult↗
PubMedDate not supplied

Effect of different inhibitors on the intracellularly and extracellularly generated chemiluminescence induced by formylmethionyl-leucyl-phenylalanine in polymorphonuclear leukocytes. Cellular response in the presence of mannitol, benzoate, taurine, indomethacin and NDGA.

When polymorphonuclear leukocytes (PMNL) interact with the soluble stimulus formylmethionyl-leucyl-phenylalanine (FMLP), the cells increase their production of oxidative metabolites. This increased production can be measured as lumino-amplified light emission or chemiluminescence (CL). In the present report, experimental systems which allow a quantitation of extracellularly and intracellularly generated metabolites have been used, and the effect of mannitol, benzoate, taurine, indomethacin and nordihydroguaiaretic acid has been investigated. The presence of the hypochlorous acid scavenger taurine had no effect on the intracellular response, whereas the extracellular response was reduced with around 50%. The hydroxyl radical scavenger mannitol had only minor effects on the response, whereas benzoate, another hydroxyl radical scavenger, reduced the extracellular response with around 50% and the intracellular response with more than 90%. Indomethacin, an inhibitor of arachidonic acid metabolism, did not influence the response, whereas NDGA, also an inhibitor of the arachidonic acid metabolism, totally abolished both the extracellular and the intracellular response. The use of scavengers/inhibitors as a means of determining the mechanisms of light emission, and the origin of chemiluminescence produced by neutrophils stimulated by FMLP is discussed.

Adult↗