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PubMed1978

[Effect of actinomycin D, carminomycin and bleomycin and their joint use with serotonin and zymosan on the functional state of the peritoneal macrophages].

The study of the effect of actinomycin D, karminomycin and bleomycin used alone or in combination with zimozan or serotonine on the functional state of the peritoneal macrophages showed that the use of the antibiotics in mice without tumors induced a decrease mainly in the absorptive capacity of the macrophages not changing significantly their digestive activity. The same antibiotics did not significantly change the initial low values of the functional activity of the cells in mice with transplantable tumors. The use of zimozan after completeness of the treatment course with actinomycin D, karminomycin and bleomycin in mice without tumors had a stimulating effect on the functional activity of the macrophages. Zimozan had a stimulating effect on the functional activity of the cells in mice with transplantable tumors only on its use after completeness of the treatment course with actinomycin D or bleomycin. Serotonine in combination with the above antibiotics had no stimulating effect on the functional activity of macrophages in mice both with and without tumors.

Animals↗
PubMed1976

A properdin system intermediate formed by zymosan and serum at 0 degrees C.

The interaction of guinea pig or rat serum with Z at 0 degrees C leads to the formation of properdin pathway intermediate, ZPI, whose activity is assessed by its capacity to deplete the titer of cobra venom inducible lysis in diluted rat serum. The formation of ZPI does not require C1 or C2 and is not diminished by prior absorption of the serum with Z. In contrast, removal of P suppresses ZPI formation. Both Ca++ and Mg++ are essential cofactors for the formation of this intermediate whose function is abrogated in the presence of anti-C3, anti-P, but not by anti-Factor B. Since C4-deficient guinea pig serum is also effective in ZPI formation, the data suggest that ZPI is an alternative pathway intermediate containing both P and C3.

Animals↗
PubMed1980

Resistance to experimental peritonitis induced by local nonspecific stimulation of the reticuloendothelial system.

Zymosan, a yeast cell wall preparation from Saccharomyces cerevisiae, stimulates the reticuloendothelial system (RES) in animals. Pretreatment with zymosan induces resistance to several types of shock. We have shown evidence that zymosan given intraperitoneally (IP) induces greater protection than intravenous (IV) zymosan against E coli peritonitis in the rat. Moreover, IP zymosan has few systemic RES effects, which are commonly associated with IV zymosan. IV and IP zymosan stimulation were compared for effectiveness against experimental fibrinopurulent peritonitis in dogs (a peritonitis model quite similar to clinical peritonitis). Ten dogs received zymosan IV (10 mg/kg), ten dogs received zymosan IP (10 mg/kg), and eight dogs received an equal volume of saline IP on three consecutive days. On day 4, a 7.5 cm length of terminal ileum was isolated and its blood supply ligated to create an infarcted, blind loop of bowel. This loop was left in the peritoneal cavity for five days. Five-day survival was 80% (8/10) for the zymosan IP (P less than 0.05), 60% (6/10) for the zymosan IV and 12.5% (1/8) for the saline controls. All survivors were sacrificed at five days and found to have an intact enteric anastomosis with varying degrees of walled-off abscess at the site of the necrotic loop. Histologic evaluation of intraabdominal organs, peritoneum, and abscess wall was carried out. The IP zymosan had no significant systemic RES effects, whereas the IV zymosan produced a marked increase in liver and spleen weights. These findings reinforce the hypothesis that local nonspecific RES stimulation could have a major role in the preparation of certain high-risk patients for abdominal surgery where the chance of peritoneal soilage is high.

Animals↗
PubMed1996

A role for the beta2 integrin CD11b in mediating experimental lung injury in mice.

We have investigated the requirement of neutrophil emigration and the role for CD11b/CD18-mediated events in the experimental induction of acute lung injury. BALB/c mice received lipopolysaccharide (LPS) (3 mg/kg) intravenously (i.v.) 2 h prior to i.v. zymosan (10 mg/kg) and extravascular albumin accumulation was assessed after 30 min. Compared with saline-treated controls, zymosan alone caused a 6-fold increase in the accumulation of 125I-human serum albumin in whole lung tissue (P<0.05). Combined treatment with LPS and zymosan further increased extravascular albumin accumulation (P<0.05 compared with zymosan alone). The monoclonal antibody 5C6, directed against murine CD11b, was injected, 1 mg i.v. 15 min prior to LPS or 15 min before the zymosan, and compared with immunoglobulin G-injected controls. Albumin accumulation was significantly reduced by 5C6 when given prior to the LPS (P<0.01), but not when given before zymosan in the combined LPS and zymosan treatment. Interestingly, albumin accumulation induced by zymosan alone was not reduced by 5C6. The lungs of the mice treated with LPS and zymosan showed a marked, diffuse accumulation of inflammatory cells which, by light microscopy, appeared to be interstitial. Foci of neutrophil aggregates were seen in noncapillary microvessels, and pretreatment with 5C6 appeared to reduce their frequency. In the animals treated with zymosan alone, LPS alone, or LPS and zymosan in combination, electron microscopy established that approximately 25% of all nucleated cells were neutrophils: 99% of the neutrophils were restricted to the intravascular compartment. Pretreatment with 5C6 prior to LPS and zymosan treatment reduced the increase in percentage of neutrophils by half. These results indicate a disassociation between induction of permeability and neutrophil emigration in our murine model and suggest that the release of neutrophil-derived factors such as platelet-activating factor, proteases, or oxidants may be involved.

Animals↗
PubMed2006

Optimization of conditions for in vitro production of radical oxygen species and expression of tissue factor by canine mononuclear cells and granulocytes for use in high-throughput assays.

The purpose of this study was to optimize conditions for high throughput measurement of radical oxygen species (ROS) production and expression of tissue factor, also termed procoagulant activity, by canine leukocytes. Granulocytes and mononuclear cells were separated by density gradient centrifugation from peripheral blood collected on several occasions from three healthy large breed dogs. To determine optimal conditions for ROS production, granulocytes were incubated for 1 or 3h in PBG (PBS containing 0.5% BSA and 5mM glucose) or RPMI containing 10% fetal bovine serum (FBS); lipopolysaccharide (LPS), zymosan, peptidoglycan (PGN) and phorbol myristate acetate (PMA) were used as stimuli. ROS was assessed by conversion of the nonfluorescent dye dihydrorhodamine 123 to fluorescent rhodamine 123 by radical species released into the media. To identify optimal conditions for expression of tissue factor, mononuclear cells were incubated for 5h in RPMI containing different concentrations of heat-inactivated FBS (HI-FBS), and LPS, zymosan, PGN or PMA as stimuli. Expression of tissue factor was determined using a one-stage recalcification assay performed in an automated nephelometric coagulation analyzer. Neither LPS nor zymosan increased ROS production by granulocytes incubated in PBG media. In contrast, granulocytes incubated in RPMI had dose-dependent increases in ROS production in response to zymosan and PGN. ROS production was significantly increased by incubation with concentrations of LPS of 0.01microg/ml or greater, and by zymosan concentrations of 0.1microg/ml or greater. ROS production in response to incubation with PMA was significantly increased starting at 10(-7)M, and was significantly greater for cells incubated in RPMI than cells incubated in PBG. LPS-, zymosan- and PGN-stimulated procoagulant activity increased in a dose-dependent manner, whereas PMA-stimulated procoagulant activity peaked at 10(-7)M. Increasing concentrations of HI-FBS significantly increased LPS-, zymosan- and PGN-induced procoagulant activity of mononuclear cells. Results obtained in this study indicate production of ROS by canine granulocytes is optimal when these cells are incubated for 3h in RPMI with LPS (0.1microg/ml), zymosan (10 microg/ml), PGN (10 microg/ml), and PMA (10(-7)M). Furthermore, canine mononuclear cells express procoagulant activity in response to LPS, zymosan, PGN, and PMA, and responses to LPS, zymosan and PGN are enhanced by the addition of HI-FBS. These findings suggest that HI-FBS retains important serum proteins that facilitate interactions between each of these bacterial or yeast derived products and the mononuclear cells. Consequently, future studies regarding the regulation of procoagulant activity by canine mononuclear cells should be performed in the presence of HI-FBS. Both assays utilized in this study allow high throughput of samples, and therefore are appropriate choices for rapid screening of conditions and/or therapeutic interventions affecting the canine inflammatory system.

Animals↗
PubMed1993

Formation of diacylglycerol, inositol phosphates, arachidonic acid and its metabolites in macrophages.

Treatment of macrophages with zymosan, 4 beta-phorbol 12-myristate 13-acetate (PMA) and fluoride but not with A 23187 or arachidonic acid (delta Ach) leads to a generation of diacylglycerol (acyl2Gro). Formation of inositol phosphates is achieved with zymosan, only. An elevation of intracellular calcium is obtained with zymosan and A 23187 but not with PMA, fluoride or delta Ach. Prior treatment of the cells with phorbol ester for 3 h which has been shown recently to result in a down-regulation of protein kinase (PK) C-beta but not PKC-delta [Duyster, J., Schwende, H., Fitzke, E., Hidaka H. & Dieter P. (1993) Biochem. J. 292, 203-207] has no effect on the zymosan-induced formation of acyl2Gro or inositol phosphates but inhibits the PMA-induced generation of acyl2Gro. Down-regulation of PKC-delta by prior phorbol ester treatment for 24 h augments the zymosan-induced generation of acyl2Gro and inositol phosphates. The acyl2Gro lipase inhibitor RG 80267 inhibits the PMA-induced and fluoride-induced generation of prostaglandin (PG) E2, reduces the zymosan-induced release of PGE2 by 50% but has no effect on PGE2 formation of unstimulated, A 23187-treated or delta Ach-treated cells. Furthermore, RG 80267 enhances accumulation of delta Ach-labeled acyl2Gro in response to zymosan, PMA and fluoride. These data indicate that zymosan activates a phosphatidylinositol 4,5-bisphosphate-specific phospholipase (PL) C, that generation of acyl2Gro by PMA and fluoride occurs via hydrolysis of other phospholipids, that PKC-beta is involved in the PMA-induced generation of acyl2Gro and PKC-delta negatively modulates the zymosan-induced activation of PLC and PMA and fluoride induce a liberation of delta Ach from acyl2Gro, A 23187 activates the PLA2 pathway and zymosan stimulates both, the acyl2Gro- and PLA2-pathway.

Animals↗
PubMed1985

A beta-glucan inhibitable receptor on human monocytes: its identity with the phagocytic receptor for particulate activators of the alternative complement pathway.

The ligand specificity of the human monocyte receptor that mediates phagocytosis of particulate activators of the human alternative complement pathway was defined by inhibiting the phagocytic response with glycans known to be present in zymosan. When monocytes in monolayers were preincubated with 100 micrograms/ml of beta-glucan and then incubated with 1.25 to 2.5 X 10(6) zymosan particles, the percentage of cells that exhibited phagocytosis was inhibited in a time-dependent manner; maximal inhibition occurred within 20 min of preincubation. beta-Glucan inhibited monocyte phagocytosis of zymosan and rabbit erythrocytes (Er) in a similar dose-dependent fashion and at 100 micrograms/ml reduced monocyte ingestion of 5 X 10(6)/ml zymosan and 2 X 10(8)/ml Er by 63 +/- 8% and 68 +/- 16% (mean +/- SD, n = 3), respectively. The other glycan constituent of zymosan, mannan, was less than 1% as active, and 10 mg/ml of mannan reduced the number of monocytes ingesting zymosan and Er by 56 +/- 12% and 26 +/- 11%, respectively. At concentrations as high as 500 micrograms/ml, beta-glucan had no effect on monocyte Fc, C3b, or fibronectin receptor-mediated functions. Enzymatic hydrolysis of beta-glucan and alpha-mannan with beta-glucosidase or beta-glucanase before their incubation with monocytes abrogated their inhibitory capacity, whereas hydrolysis with alpha-mannosidase or alpha-glucosidase did not. Neither of the two alpha-glucans tested (dextran T-70 and nigeran) affected monocyte ingestion of zymosan particles or sheep erythrocytes (Es) sensitized with rabbit 7S anti-Es (EsIgG) at concentrations as high as 2 mg/ml. In contrast, a number of beta-glucans were active against zymosan but not EsIgG ingestion with a 75% reduction in the number of monocytes ingesting zymosan occurring with 100 micrograms/ml laminarin, 500 micrograms/ml soluble pachyman, and 900 micrograms/ml of soluble pustulan. The galactan, agarose, either in suspensions at 2 mg/ml or in a soluble portion at 600 micrograms/ml failed to affect monocyte ingestion of zymosan particles or Er. Thus, the monocyte receptor for particulate activators that is specifically inhibited by beta-glucan at a rate compatible with a phagocytic process and that recognizes beta-glucans but not alpha-glucans, mannan, or galactan is a beta-glucan receptor.

Binding, Competitive↗
PubMed1995

The gut: a cytokine-generating organ in systemic inflammation?

The aim of this study was to test the hypothesis that the gut is capable of becoming a cytokine-generating organ following either a lethal or nonlethal inflammatory insult. Adult male rats were given an intraperitoneal challenge with saline, or with a nonlethal (.1 mg/g) or LD50 (.5 mg/g) dose of zymosan. Mesenteric lymph nodes, efferent mesenteric lymph, liver, spleen, and blood (portal and systemic) were obtained at 2, 4, 6, 8, or 10 h post challenge. Organs, lymph, and blood were tested for bacterial translocation (BT); blood and lymph were assayed for tumor necrosis factor (TNF) and IL-6. After .1 mg/g zymosan, BT was limited to the mesenteric lymph node complex only; .5 mg/g zymosan promoted BT to blood, mesenteric lymph, and organs (p < .05 vs. control or .1 mg/g zymosan). The magnitude of portal bacteremia was greater than systemic bacteremia (p < .003). Serum TNF peaked at 2 h (p < .05 vs. control), and serum IL-6 peaked at 4-6 h (p < .05 vs. control) post zymosan challenge. Portal and systemic bioactivity was similar for either cytokine, and serum bioactivity did not correlate with zymosan dose. TNF bioactivity was increased in the mesenteric lymph at 2 h post challenge with .5 mg/g zymosan only (p < .05 vs. control or .1 mg/g zymosan). IL-6 bioactivity was increased in the mesenteric lymph at 4 through 10 h post zymosan challenge (p < .05 vs. control), but was similar with either dosage of zymosan. In conclusion, the gut may be capable of producing cytokines in response to an inflammatory stimulus, even in the absence of portal or systemic spread of bacteria. The magnitude of the cytokine response does not correlate with the magnitude of bacterial translocation.

Analysis of Variance↗
PubMed1986

Induction of macrophage lysosomal hydrolase synthesis and secretion by beta-1,3-glucan.

Studies were undertaken to elucidate the active component in zymosan necessary to induce the delayed-onset synthesis and secretion of representative lysosomal hydrolases, hexosaminidase, and beta-glucuronidase in macrophages. Resident mouse peritoneal macrophages were challenged with zymosan particles and particulate beta-1,3-glucan, the major subcomponent of zymosan. Zymosan was found to induce a rapid secretion of preformed hexosaminidase with maximal release (75%) occurring 6 hr after the addition of zymosan. By contrast, beta-1,3-glucan was totally inactive in this respect. However, both zymosan and beta-1,3-glucan were found to induce the delayed-onset synthesis and secretion of hexosaminidase and beta-glucuronidase while maintaining constant cellular enzyme levels over a 5-day period following the addition of stimulus. These late responses were almost totally blocked by a noncytolytic concentration of cycloheximide, indicating their dependence on de novo protein synthesis. Mannan, the second major subcomponent of zymosan, had no effect on either immediate secretion or delayed-onset synthesis and secretion of hexosaminidase. These results suggest that the induction of the delayed-onset synthesis and secretion of the lysosomal hydrolases by zymosan may be dependent on the glucan subcomponent of zymosan. Moreover, it would also appear that the release of preformed lysosomal enzymes is not the trigger for the delayed-onset synthesis and secretion of hexosaminidase.

Animals↗
PubMed2001

In vitro complement activation favoring soluble C5b-9 complex formation alters myocellular sodium homeostasis.

BACKGROUND: Deranged Na(+) homeostasis in skeletal muscle is closely associated with excessive complement activation that is encountered during sepsis. Recent evidence suggests that soluble C5b-9 complexes (SC5b-9), which are readily detected in plasma during sepsis and have long been considered irrelevant nonmembrane binding end products of complement activation, may have numerous biologic effects. The purpose of this study, therefore, was to determine the effects of SC5b-9 on myocellular ion homeostasis and its mechanism(s) of action. METHODS: Hindlimb fast-twitch extensor digitorum longus (EDL) was freshly isolated from rats weighing 50 to 70 g and then incubated at 30 degrees C for 60 minutes in normal Krebs-Henseleit buffer (KHB, pH 7.4) containing 10% zymosan-activated rat serum (10 mg/mL at 37 degrees C for 60 minutes) as a source of SC5b-9. Zymosan particles were removed by centrifugation after activation to exclude any noncomplement direct effects. Heat-inactivated rat serum (56 degrees C for 30 minutes) was used as control. EDL muscle was also incubated with pertussis toxin (1 microg/mL), in Ca(2+)-free KHB, with thapsigargin (0.3 or 3 micromol/L), or with ouabain (0.01, 0.1 or 1 micromol/L) before and/or during incubation with 10% zymosan-activated or heat-inactivated rat serum. Intracellular Na(+) and K(+) contents ([Na(+)](i) or [K(+)](i)) of EDL muscle were determined by using flame photometry after washing in ice-cold Na(+)-free Tris-sucrose buffer. SC5b-9 in zymosan-activated human serum was determined by SC5b-9 enzyme-linked immunoassay. RESULTS: SC5b-9 in zymosan-activated human serum significantly increased by 400% as compared with nonactivated, normal human serum. Zymosan-activated rat serum markedly increased [Na+]i without affecting [K(+)](i) in fast-twitch EDL muscle, which was completely inhibited by pertussis toxin, removal of extracellular Ca(2+) or depletion of intracellular Ca(2+) with thapsigargin. The addition of ouabain (at micromolar concentrations) increased myocellular [Na(+)](i) and decreased myocellular [K(+)](i) in both the zymosan-activated and the heat-inactivated rat serum groups. The effects of ouabain on myocellular [Na(+)](i) and [K(+)](i) were equivalent in these 2 groups. Zymosan-activated and heat-inactivated rat serum had similar effects on myocellular [K(+)](i) in the presence or absence of pertussis toxin, removal of extracellular Ca(2+) or depletion of intracellular Ca(2+). CONCLUSIONS: Zymosan-activated rat serum (presumed SC5b-9 enriched) selectively alters Na(+) homeostasis in isolated fast-twitch skeletal muscle. The mechanisms for such effects may be linked to G-proteins, Ca(2+) flux and Na(+),K(+)-adenosine triphosphatase pump binding site blockade.

Animals↗
PubMed2003

Partially opened triple helix is the biologically active conformation of 1-->3-beta-glucans that induces pulmonary inflammation in rats.

1-->3-beta-Glucans produce pulmonary inflammation in rats and are commonly found in indoor air dust samples. Conformation is an important factor determining the biological activity of 1-->3-beta-glucans. The partially opened triple-helix conformation induced by NaOH treatment and the annealed triple-helix conformation have been identified by fluorescence resonance energy transfer spectroscopy in our previous study. The objective of this study was to examine the role of these conformations of 1-->3-beta-glucans in the induction of pulmonary inflammation in rats. A partially opened triple-helix conformation of the known inflammatory 1-->3-beta-glucan zymosan was prepared by treating zymosan with NaOH followed by neutralization and dialysis. The annealed triple-helix conformation was prepared by allowing the partially opened triple-helix conformation to anneal for 9 d at room temperature. Rats were exposed to fresh or annealed NaOH-treated zymosan via intratracheal instillation. The results show that the zymosan-induced pulmonary inflammatory responses were significantly reduced after the 9-d annealing period, which suggests that this inflammatory response was dependent on the conformation of zymosan. Freezing NaOH-treated zymosan (for 7 d) inhibited the annealing process. Exposure of rats to thawed preparations of zymosan resulted in the same inflammatory responses as the freshly prepared partially opened triple-helix zymosan. In contrast, the potency of untreated zymosan did not change significantly following a 7-d annealing period, indicating that annealing occurs only after the conformation has been modified by NaOH treatment. This study indicates that the partially opened triple helix of 1-->3-beta-glucans is more active than the closed conformation in inducing pulmonary inflammation in rats.

Animals↗
PubMed1990

Protein malnutrition predisposes to inflammatory-induced gut-origin septic states.

The development of an uncontrolled inflammatory response has been implicated in the pathogenesis of adult respiratory distress syndrome and multiple-organ failure. Because zymosan activates complement and induces a systemic inflammatory response, the effect of zymosan on intestinal structure and barrier function was measured in normally nourished (NN) and protein malnourished (PM) mice. Normally nourished and protein malnourished (up to 21 days) mice challenged intraperitoneally with zymosan (0.1 mg/g body weight) were killed 24 hours after zymosan challenge and their organs cultured for translocating bacteria. Zymosan-induced bacterial translocation was limited to the mesenteric lymph nodes of the NN mice, whereas translocating bacteria spread from the gut to the liver, spleen, and blood stream (p less than 0.05) in the PM mice. Zymosan-induced bacterial translocation appeared to be related primarily to the combination of mucosal injury and a disruption of the gut flora ecology in the PM mice and to mucosal injury in the NN mice. The extent of mucosal injury was greater the longer the mice were protein malnourished before zymosan challenge. The effect of zymosan on survival was measured in separate groups of mice. At a dose of 0.1 mg/g body weight, no deaths occurred in NN mice or in 7-day PM mice. However 20% of the 14-day PM mice and 80% of the 21-day PM mice receiving zymosan died. Thus PM predisposes to mucosal damage and the development of potentially lethal gut origin septic state during periods of systemic inflammation.

Animals↗