Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ZYMOSAN”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 937 records · Page 52Linked to original sources
PubMedDate not supplied

Chemiluminescence properties of human, canine and rat polymorphonuclear cells.

Human as well as canine and rat polymorphonuclear cells (PMN) were separated from whole blood by centrifugation. Two-step discontinuous Percoll gradients with distinct different densities were used. The chemiluminescence properties of the isolated PMN and of phagocytes in small quantities of whole blood were compared in luminol-enhanced assays after stimulation with various agents: non-opsonized zymosan (3.5 g/l), phorbol myristate acetate (PMA, 2.8 x 10(-6) mol/l), calcium ionophore A 23187 (10(-5) mol/l) and N-formyl-methionyl-leucyl-phenylalanine (FMLP, 3.5 x 10(-6) mol/l). The isolated cells of the three species responded to all of the various stimuli. Species-related sensitivity could be ordered: human greater than canine greater than rat. Response to the various agents in the human cells can be ranked: PMA greater than or equal to A 23187 greater than zymosan greater than FMLP; for the dog: A 23187 greater than PMA greater than zymosan greater than FMLP; and for the rat: zymosan greater than or equal to PMA greater than FMLP greater than or equal to A 23187. Time course and peak maximum response were different upon stimulation in the absence and presence of autologous plasma. Distinct soluble stimuli resulted in maximum responses below the baseline in the whole blood assays with canine (FMLP) and rat (FMLP, A 23187) phagocytes.

Animals↗
PubMed1980

Metastasis: reticuloendothelial system and organ retention of disseminated malignant cells.

The lung retention patterns of B16 melanoma cells were determined after intravenous injection of [125l]dUrd-labelled tumor cells into B16 melanomabearing mice. Experiments were performed with mice undergoing acute or chronic reactions to bacterial endotoxin or zymosan, both of which were shown to modify the activity of the reticuloendothelial system as assessed by carbon clearance assays. On the one hand, the release of arrested melanoma cells from the lungs was retarded in mice with both endotoxin-and zymosan- induced acute inflammation. There was a parallel increase in the numbers of pulmonary tumor nodules which developed after injection of non-radiolabelled melanoma cells into similarly treated groups of mice. On the other hand, fewer tumor cells were retained in the lungs of mice undergoing chronic responses to endotoxin, and fewer pulmonary tumor nodules subsequently arose after injection of unlabelled cells. However, in mice pre-treated with zymosan, retention of melanoma cells was not different from that in controls and greatly increased numbers of pulmonary nodules grew in zymosan pre-treated mice receiving non-radiolabelled cells. These experiments were discussed in terms of the contribution of the reticuloendothelial system to the release of arrested cancer cells from the pulmonary vasculature.

Animals↗
PubMed1992

Age-related alterations in superoxide anion generation in mouse peritoneal macrophages studied by repeated stimulations and heat shock treatment.

The ability of thioglycollate-elicited peritoneal macrophages (PM) from young and senescent mice to generate superoxide anions (O2-) under repeated stimulation or thermal stress was studied using either zymosan, opsonized zymosan (OZ), or phorbol myristate acetate (PMA). A diminished capacity to recover from repeated stimulation was found with aging. When stimulated for a second time 24 hours after the primary stimulation, PM from young animals generated 80% of the initial O2- responses to either zymosan, or OZ. Under the same conditions, PM from senescent mice generated 62% of the initial O2- produced in response to zymosan, and 45% in response to OZ. In both age groups the response to a second PMA stimulation comprised only 10% of the primary response. A considerably diminished capacity to generate O2- was also demonstrated in PM from senescent mice after recovery from exposure to thermal stress. Exposure to 42.5 degrees C for 20 minutes was found to be the threshold temperature for irreversible loss of activity in senescent PM, whereas at this temperature, PM from young animals recovered up to 70% of their O2- generating activity. Since NADPH oxidase and superoxide dismutase activities were only mildly affected by the hyperthermia in all age groups, they could not account for the age-related decline in the recovery from stress. Age-related alterations in signal transduction or receptor alterations could possibly play a primary role in this decline.

Aging↗
PubMed1990

Glucocorticoids fail to inhibit arachidonic acid metabolism stimulated by hydrogen peroxide in the alveolar macrophage.

We have previously demonstrated that the biologically important oxidant hydrogen peroxide (H2O2) triggers release and metabolism of arachidonic acid (AA) in the alveolar macrophage (AM). In this study, we evaluated the ability of glucocorticoids to inhibit rat AM AA metabolism stimulated by H2O2, as compared to the particulate zymosan. Methylprednisolone and other glucocorticoids failed to significantly inhibit release of AA stimulated by H2O2, while markedly reducing AA release in response to zymosan. Similarly, methylprednisolone only weakly inhibited synthesis of thromboxane (Tx)B2 stimulated by H2O2, while inhibiting zymosan-induced eicosanoid synthesis to a marked degree. On the other hand, the phospholipase inhibitor mepacrine strongly inhibited AA release and TxB2 formation stimulated by both H2O2 and zymosan, indicating that H2O2 induced AA metabolism is indeed susceptible to pharmacologic inhibition. The failure of glucocorticoids to inhibit AA metabolism stimulated by H2O2 in the AM may in part explain their inability to ameliorate oxidant-mediated lung inflammation and injury.

Animals↗
PubMed1993

Effect of acute oral administration of alcohol on superoxide anion production from mouse alveolar macrophages.

The production of superoxide anions (superoxide) from alveolar macrophages stimulated or not with opsonized zymosan was investigated in the mouse after acute oral administration of alcohol (6.5 g/kg). Superoxide production was assayed using a nitroblue tetrazolium (NBT) reduction and chemiluminescence assay. In the absence of opsonized zymosan, superoxide concentration was not affected 1 h after ethanol treatment but was significantly increased 15 and 24 h after treatment. In the presence of opsonized zymosan, a biphasic response was observed. Superoxide production was significantly reduced 1 and 3 h after administration but was increased 15 and 24 h after treatment. One hour after treatment, the percentage of cells that phagocytized opsonized zymosan and reduced NBT was significantly decreased, whereas 24 h after alcohol treatment, phagocytosis was normal and the percentage of cells reducing NBT was significantly increased. The activity of cytosolic superoxide dismutase from alveolar macrophages was not altered 1 h after administration but was significantly reduced 24 h later. Considering the functions of alveolar macrophages in the defense of the lung, these alterations in the production of reactive oxygen species after ingestion of alcohol could explain why alcoholics are more sensitive to pulmonary infections.

Animals↗
PubMed1997

Secretion and inactivation of myeloperoxidase by isolated neutrophils.

Neutrophils prevent infection by ingesting and killing microorganisms but oxidants and proteases released by neutrophils damage host tissues. Our aim was to identify factors that regulate oxidant production by the enzyme myeloperoxidase (MPO) following secretion of MPO into the medium. Cells stimulated with phorbol myristate acetate (PMA) or opsonized zymosan particles secreted MPO and released superoxide free radicals (.O2-). Dismutation of .O2- produced hydrogen peroxide (H2O2) and MPO catalyzed the oxidation of chloride ion by H2O2 to produce the toxic oxidant hypochlorous acid (HOCl). Adding the enzyme superoxide dismutase (SOD) to increase the rate of conversion of .O2- to H2O2 had pH-dependent effects on HOCl production. From pH 6.0 to 7.4, SOD promoted HOCl production by up to 500% but SOD had no effect at pH 7.6 and inhibited by 40 +/- 10% at pH 7.8. In further experiments at pH 7.0, MPO activity in the cells decreased by 25 +/- 2 and 44 +/- 4% during 1-h incubations with PMA and zymosan. Only 1 +/- 0 and 3 +/- 1% of the total activity was found in the medium, indicating that most of the secreted MPO was inactivated. Loss of activity was not accompanied by proteolytic destruction of the MPO protein, which was measured with anti-MPO antibodies. SOD raised the amount of active MPO in the medium two- to sevenfold, but adding deferoxamine to chelate iron or adding ferric ion had no effect. The ionophore A23187 was as effective as zymosan as a stimulus for MPO secretion but .O2- production by ionophore-stimulated cells was less than 4% of that of PMA- or zymosan-stimulated cells and most of the secreted MPO was found active in the medium. When PMA-stimulated cells were incubated with purified MPO, the added MPO activity was lost from the medium. Binding or proteolysis did not account for loss of activity as indicated by recovery of added radioiodinated MPO from the medium. The visible absorption spectrum of MPO was lost, indicating destruction of the iron-containing prosthetic group. Loss of activity and loss of the MPO spectrum were blocked by SOD but not by deferoxamine or catalase. The results indicate that, in the physiological pH range, inactivation of MPO in the medium suppressed HOCl production. Inactivation required O2- but not HOCl, H2O2, or free iron. Inactivation of secreted MPO may limit MPO-mediated damage to host tissues by stimulated neutrophils.

Humans↗
PubMed1975

Comparison of the effect of various antisera and cobra venom factor on inflammatory reactions in guinea-pig skin. I. Non-specific inflammation due to the intradermal injection of turpentine.

Guinea-pigs were treated with agents which lowered the serum complement levels and the effect on the inflammatory reaction to intradermal turpentine was studied. A comparison was made between two antisera to beta1C/beta1A globulin which had been prepared in different ways. One was made using C3 fixed to zymosan particles as the antigen, and the other using chemically extracted beta 1C/beta1A globulin. The antisera to beta1C/beta1A globulin (zymosan) was found to have the greater anti-inflammatory activity. The effect of each on the parameters of complement studied, and on the circulating platelet count, was much the same. An antiserum to serum factors fixed to zymosan during C3 activication was prepared free of anti-beta1C/beta1A globulin antibodies. This was found to have some of the anti-inflammatory activity of the anti-beta1C/beta1A globulin (zymosan), as well as lowering total complement levels. Anti-gamma globulin andheterologous immune complexes also lowered serum complement levels and were antiinflammatory. However, all the above agents were also found to reduce the number of circulating platelets. This was in contrast to CVF which reduced complement levels by 90 per cent. but had no effect on platelet numbers. CVF also reduced the inflammatory response but was no more effective than the other agents. In view of these findings a role for the participation of the complement system, possibly involving the alternate pathway of activation of C3, is discussed as well as the participation of platelets in the reaction.

Animals↗
PubMed1993

Granulocyte colony-stimulating factor enhances the extracellular emission of reactive oxygen from neutrophils stimulated with formylmethionylleucylphenylalanine.

Pretreatment of neutrophils with granulocyte colony-stimulating factor (G-CSF) enhanced luminol-dependent chemiluminescence emission by the stimulation of formylmethionylleucylphenylalanine (FMLP), opsonized zymosan, and zymosan. The intensity of the priming effects was in the following order: FMLP > zymosan > opsonized zymosan. However, the priming effect of G-CSF was not detected by the stimulation of phorbol myristate acetate. The reaction curve with the stimulation of FMLP showed a bimodal shape, and the elevation of the first peak by the priming effect was further prominent in comparison with the elevation of the second peak. This indicates that G-CSF mainly enhances the extracellular release of oxygen radicals in response to the stimulation with FMLP. This is the first report investigating intra- and extracellular events in chemiluminescence reaction of neutrophils primed with G-CSF.

Cytochalasin B↗
PubMed2000

A flow cytometric approach to the study of crustacean cellular immunity.

Responses of hemocytes from the crayfish Procambarus zonangulus to stimulation by fungal cell walls (zymosan A) were measured by flow cytometry. Changes in hemocyte physical characteristics were assessed flow cytometrically using forward- and side-scatter light parameters, and viability was measured by two-color fluorescent staining with calcein-AM and ethidium homodimer 1. The main effects of zymosan A on crayfish hemocytes were reduction in cell size and viability compared to control mixtures (hemocytes in buffer only). Adding diethyldithiocarbamic acid, an inhibitor of phenoloxidase, to hemocyte and zymosan mixtures delayed the time course of cell size reduction and cell death compared to zymosan-positive controls. The inclusion of trypsin inhibitor in reaction mixtures further delayed the reduction in hemocyte size and cell death, thereby indicating that a proteolytic cascade, along with prophenoloxidase activation, played a key role in generating signal molecules which mediate these cellular responses. In addition to traditional methods such as microscopy and protein chemistry, flow cytometry can provide a simple, reproducible, and sensitive method for evaluating invertebrate hemocyte responses to immunological stimuli.

Animals↗
PubMed1995

Effect of agents which modify reticuloendothelial system function on acute phalloidin-induced lethality and hepatotoxicity in mice.

The relationship between reticuloendothelial system (RES) function and acute phalloidin intoxication was studied in mice. Pretreatment with compounds that stimulate (zymosan) or depress (methyl palmitate and praseodymium nitrate, Pr(NO3)3) the RES resulted in protection against phalloidin-induced lethality and hepatotoxicity, as assessed by morphological analysis. However, triolein (which stimulates the RES) was ineffective against phalloidin. The timing of pretreatment with the effective compounds showed a correlation between modified in vivo RES function (phagocytosis) and protection against the toxin. The effects of pretreatment with zymosan and Pr(NO3)3 were further characterized. Hepatic damage induced by phalloidin was significantly decreased by these agents, as judged by morphological analysis as well as by serum aspartate aminotransferase and alanine aminotransferase release. This study also showed that there was no correlation between the capacity of Kupffer cells to produce nitrite and prophylaxis against phalloidin. However, liver cell proliferation was increased by zymosan and Pr(NO3)3 in parallel with protection against the toxin. Furthermore, freshly isolated hepatocytes from zymosan- or Pr(NO3)3-treated mice were less sensitive to phalloidin in vitro. These results indicate that the protective effect of these agents against phalloidin-induced hepatotoxicity may be mediated by their mitogenic properties.

Animals↗
PubMed1982

Stimulation of the hexose monophosphate shunt activity in human polymorphonuclear leukocytes.

The glucose metabolism in human polymorphonuclear (PMN) leukocytes was stimulated by latex particles, zymosan particles, gamma-G globulin and formylmet-leu-phe (FMLP) peptide. Maximum stimulation occurred when zymosan particles in amounts above 0.25 mg/ml per 4 X 10(6) leukocytes were used. Latex particles, gamma-G globulin and FMLP stimulated the glucose oxydation less than zymosan particles. The glucose oxydation increase in proportion to the amount of latex particles and gamma-G globulin in the measured range, while the dose response curve using FMLP shows maximum activity at a consentration of the peptide of 5 X 10(-5)M per 4 X 10(6) leukocytes. It is likely that FMLP and gamma-G globulin act on the glucose metabolism via cell surface receptors. The synthetic polystyrene particles (latex) do not occupy these receptors, but stimulate the hexose monophosphate (HMP) shunt activity of the PMN via intracellular mechanisms. Opsonized zymosan particles seem to act on the leukocyte glucose metabolism via cell surface receptors as well as via intracellular mechanisms.

Glucose↗
PubMed1984

Oxygen metabolism of phagocytosing human polymorphonuclear leucocytes in diabetes mellitus.

Zymosan stimulated oxygen metabolism was investigated in polymorphonuclear leucocytes (PMN) from 6 diabetic patients. Oxygen uptake and superoxide production were continuously measured in the presence of autologous or control serum and non-opsonized zymosan, or in the absence of serum and preopsonized zymosan. The only significant impairment in the diabetic cells studied was a lower oxygen uptake in the presence of autologous serum. This defect was normalized by addition of control serum or by omitting the serum and stimulating with opsonized zymosan. In the absence of serum, the oxygen consumption was markedly diminished in only one subject, whereas two subjects showed a decrease of superoxide production in the presence of control serum. An inverse correlation between fasting glucose concentration and oxygen uptake could be demonstrated. However, exposure of normal PMN to hyperglycemic glucose concentration in vitro did not significantly alter their oxygen metabolism, suggesting that glucose alone could not be the only factor responsible for the impaired oxygen consumption in diabetic cells.

Aged↗
PubMed1986

Further studies of the mechanism of counter irritation by turpentine.

The influence of counter irritation by turpentine (0.2 ml) on zymosan- and carrageenan-oedemas was investigated in the rat. Zymosan-oedema was inhibited by mepyramine and methysergide and by leucopenia. It was not modified by captopril and developed normally in kininogendeficient Brown Norway rats. Leucocytes and mast cell amines but not kinins are thus involved in zymosan-oedema. The last phase of this reaction was inhibited by counter irritation alone, but the odema was largely depressed by counter irritation in rats pretreated with mepyramine and methysergide. Carrageenan-oedema was increased by kininase inhibitors and inhibited by leucopenia in normal rats. This inflammatory reaction had a small developement and was not increased by kininase inhibitors in kininogen-deficient BN rats. Leucocytes and kinins participate in the developement of this inflammatory reaction in normal rats while kinins are lacking in deficient rats. Counter irritation depressed carrageenan-oedema in deficient Brown Norway rats and suppressed the potentiating effect of kininase inhibitors in normal rats. Carrageenan oedema was nearly abolished in turpentine-treated leucopenic rats. These results suggest that the anti-inflammatory effect of counter irritation by turpentine could depend on a reduction of leucocyte accumulation into zymosan-oedema and on a reduction of both kinin formation and of leucocyte accumulation into carrageenan-oedema. The significance of T-kininogen as acute phase reactant is discussed.

Animals↗
PubMed1985

Inhibition of in vivo neutrophil accumulation by stress. Possible role of neutrophil adherence.

Psychological stress results in neural and endocrine changes which can alter various aspects of the immune system. However, the effects of stress on inflammation has not received much attention despite the fact that stress hormones, such as the corticosteroids, are known to reduce inflammation. The present study extends a previous finding that stress itself can reduce inflammation. In the first experiment, zymosan was injected into an air pouch on the dorsum of F344 rats. Half of these rats then received three hours of inescapable, intermittent, electric foot shock as a stressor. The other half of the injected rats served as nonstressed controls. A third group were given air pouches but no zymosan. Fewer neutrophils accumulated at the inflammatory site of stressed rats as compared to nonstressed control rats. However, phagocytosis of zymosan by air pouch neutrophils was higher in stressed rats. Peripheral perfusion was not altered significantly by shock, but vascular permeability was reduced in stressed rats. The effects of stress on peripheral blood leukocytes of rats not injected with zymosan was investigated. It was found that while peripheral blood monocytes and lymphocyte numbers were decreased by stress, neutrophils were not decreased. Increased neutrophil adherence was found in stressed rats. Additionally, in the presence of endotoxin, neutrophils from stressed rats did not increase their adherence as much as those of control rats. The increased adhesiveness of neutrophils in stressed animals may account for the diminished inflammatory response in the shocked rats.

Animals↗
PubMed1987

Mechanism of prostaglandin E2 inhibition of acute changes in vascular permeability.

In order to determine the mechanism of antiinflammatory activity, prostaglandin E2 (PGE2) or diluent was administered to rats 2 h prior to intradermal injections of various mediators of inflammatory vascular permeability changes. Vascular permeability was measured as the accumulation of [125I]rat serum albumin at the site of mediator injunction. PGE2 at 500 micrograms significantly inhibited protein leakage produced by histamine, platelet activating factor, zymosan, and zymosan-activated plasma. Pretreatment with PGE2 had no effect on protein leakage induced by injection of lysosomal enzymes, glucose oxidase, or xanthine oxidase. The accumulation of polymorphonuclear leukocytes (PMNs) at the site of injection of zymosan or zymosan-activated plasma was not altered by PGE2 administration. In separate experiments, the ability of PGE2 to alter phagocytosis and oxygen radical production by PMN was examined. PGE2 significantly inhibited phagocytosis at 2 h, but this returned to normal by 6 h. Production of hydrogen peroxide by PMN was not affected by PGE2. These results suggest that PGE2 prevents acute changes in vascular protein leakage by preventing endothelial cell contraction and by inhibiting specific PMN functions.

Animals↗
PubMed1988

Enhanced chemiluminescence production by phagocytosing neutrophils in psoriasis.

Using serum-coated zymosan, the generation of reactive oxidants by measurement of chemiluminescence was shown to be significantly enhanced in isolated peripheral psoriatic neutrophils compared to normal controls. This response was observed irrespective of whether zymosan was opsonized with fresh autologous or normal AB serum. However, this increased activity was reduced with zymosan was opsonized with serum that was preheated at 56 degrees C for 30 min. There was no statistical correlation of chemiluminescence activity with degranulation of beta-glucuronidase in either normal or psoriatic subjects. In addition, chemiluminescence produced by normal cells was significantly increased when zymosan was opsonized with psoriatic serum. The plasma membrane-bound enzyme, NAD(P)H oxidase, which produces superoxide in response to phagocytic stimulation, was significantly increased in psoriatic neutrophils compared to normal controls. These data add further evidence for activated neutrophils in psoriasis.

Female↗
PubMed1994

Release of monokines by pulmonary macrophages following antigen challenge in sensitized guinea pigs.

Guinea pigs were passively sensitized with immune serum to ovalbumin (OA), control serum, or saline. Twenty-four hours later, they inhaled aerosols of OA (2% in saline), saline, or lipopolysaccharide (LPS). Following anesthesia, bronchoalveolar lavage (BAL) was performed at 30, 60, 90 and 120 min postinhalation. Alveolar macrophages (AM) were isolated from the BAL fluid and incubated (18 h) in medium alone or with zymosan (1 mg/ml). Supernatants were collected and levels of interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) determined by bioassays. Unstimulated AM from animals that inhaled OA, saline, or LPS secreted similar amounts of IL-1 at 30, 60, and 90 min postinhalation. Zymosan (1 mg/ml) significantly increased IL-1 secretion by AM collected at 60 and 90 min from OA-sensitized animals that inhaled OA or saline. AM from guinea pigs sensitized to OA that inhaled OA or LPS secreted significantly increased amounts of IL-6 at 30, 60, 90, and 120 min postchallenge compared to saline sensitized controls. In all groups, AM from LPS-treated animals secreted large amounts of TNF-alpha at all sampling times postchallenge; AM from OA-sensitized and challenged animals secreted increasing amounts of TNF-alpha with time postchallenge, spontaneously and in response to zymosan. By contrast, AM from saline sensitized and challenged guinea pigs did not release detectable amounts of TNF-alpha spontaneously and secreted very low amounts in the presence of zymosan. These findings show that antigen challenge results in a rapid activation of AM isolated from BAL and suggest AM may initiate the development of inflammatory processes associated with antigen challenge.

Administration, Inhalation↗
PubMed1998

Compartmentalization of PDE-4 and cAMP-dependent protein kinase in neutrophils and macrophages during phagocytosis.

The compartmentalization of cAMP in human neutrophils during phagocytosis of serum-opsonized zymosan suggests that cAMP is an important second messenger for regulating phagocytosis. Type 4 cAMP-specific phosphodiesterase (PDE-4), cAMP-dependent protein kinase (PKA), and adenylate cyclase are the principal effector molecules for cAMP regulation in phagocytes. Immunofluorescence microscopy demonstrated that PDE-4 isoforms (HSPDE-4A, HSPDE-4B, HSPDE-4D) were targeted to the forming phagosome in neutrophils, and were colocalized with the catalytic subunit of PKA and degranulated myeloperoxidase. Phagocytosis and accumulation of PDE-4 and PKA near adherent zymosan were inhibited by elevating cAMP levels with forskolin or rolipram. cAMP, PDE-4, and PKA were localized at sites of zymosan adherence in cells treated with cytochalasin D to inhibit phagosome formation, suggesting that zymosan engagement to Fc/CR3 receptors triggers cAMP elevations at sites of phagocytosis. HSPDE-4A, HSPDE-4B, HSPDE-4D, and PKA also were localized at the forming phagosome in monocyte-derived macrophages, and the lysosomal marker CD63 demonstrated the absence of PDE-4 around internalized phagolysosomes. These results suggest that cAMP levels are focally regulated by PDE-4 at the nascent phagosome, and that PKA may phosphorylate proteins associated with pseudopodia formation and phagosome internalization.

3',5'-Cyclic-AMP Phosphodiesterases↗