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S C Lazarus

Publications and source records attributed to S C Lazarus.

At least 19 recordsLinked to original sources
PubMed2001

Human eosinophils induce mucin production in airway epithelial cells via epidermal growth factor receptor activation.

Eosinophil recruitment and mucus hypersecretion are characteristic of asthmatic airway inflammation, but eosinophils have not been shown to induce mucin production. Because an epidermal growth factor receptor (EGFR) cascade induces MUC5AC mucin in airways, and because EGFR is up-regulated in asthmatic airways, we examined the effect of eosinophils on MUC5AC mucin production in NCI-H292 cells (a human airway epithelial cell line that produces mucins). Eosinophils were isolated from the peripheral blood of allergic patients, and their effects on MUC5AC mucin gene and protein synthesis were assessed using in situ hybridization and ELISAs. When IL-3 plus GM-CSF or IL-3 plus IL-5 were added to eosinophils cultured with NCI-H292 cells, MUC5AC mucin production increased; eosinophils or cytokines alone had no effect. Eosinophil supernatant obtained by culturing eosinophils with IL-3 plus GM-CSF or IL-3 plus IL-5 also increased MUC5AC synthesis in NCI-H292 cells, an effect that was prevented by selective EGFR inhibitors (AG1478, BIBX1522). Supernatant of activated eosinophils induced EGFR phosphorylation in NCI-H292 cells. Supernatant of activated eosinophils contained increased concentrations of TGF-alpha protein (an EGFR ligand) and induced up-regulation of TGF-alpha expression and release in NCI-H292 cells. A blocking Ab to TGF-alpha reduced activated eosinophil-induced MUC5AC synthesis in NCI-H292 cells. These results show that activated eosinophils induce mucin synthesis in human airway epithelial cells via EGFR activation, and they implicate TGF-alpha produced by eosinophils and epithelial cells in the EGFR activation that results in mucin production in human airway epithelium.

Adult↗
PubMed2001

Relationship between airway inflammation, hyperresponsiveness, and obstruction in asthma.

BACKGROUND: Although the role of eosinophils in airway inflammation in chronic asthma has been extensively studied, a role for neutrophils has not been well characterized. Furthermore, prior studies have not systematically sought or controlled for factors that might confound the relationship between cellular markers of inflammation and physiologic measures of airway function. OBJECTIVE: The purpose of this study was to determine whether eosinophilic and neutrophilic inflammation independently contribute to abnormalities of airway function in asthma. METHODS: Multivariate analysis of data collected during screening and enrollment of 205 asthmatic adults for clinical trials was conducted to examine the relationships between cellular inflammation in induced sputum and FEV(1) and methacholine responsiveness (PC(20)) while confounding factors were controlled for. RESULTS: We found that age, sex, ethnicity, and use of inhaled corticosteroids were important confounding factors of the relationship between cellular inflammation and airway function. When these factors were controlled for, multivariate analysis showed that eosinophil percentage in induced sputum is independently associated with lower FEV(1) and lower PC(20) (P = .005 and P = .005, respectively). In the same models, increased sputum neutrophil percentage is independently associated with lower FEV(1) (P = .038) but not with PC(20) (P = .49). CONCLUSIONS: These results suggest that both eosinophilic inflammation and neutrophilic inflammation independently contribute to abnormalities of FEV(1) in asthma. Therapies directed specifically at control of neutrophilic inflammation might be useful in improving airway caliber in patients with chronic asthma.

Adult↗
PubMed2001

Safety and reproducibility of sputum induction in asthmatic subjects in a multicenter study.

The safety of sputum induction and the reproducibility of measurements in induced sputum in multicenter studies is unknown. We examined the safety of sputum induction in a two-visit, six-center study in 79 subjects with moderate to severe asthma (mean +/- SD FEV(1) 71 +/- 12% predicted, 67% taking inhaled corticosteroids). In addition, we compared the reproducibility of markers of inflammation in induced sputum with the reproducibility of the FEV(1) and the methacholine PC(20). The FEV(1) decreased > or = 20% from the postbronchodilator baseline in 14% of all subjects and in 25% of subjects whose initial prebronchodilator baseline was 40 to 60% of predicted. All subjects responded promptly to additional albuterol treatment, and no subject developed refractory bronchoconstriction requiring treatment other than reversal of bronchospasm in the study laboratory. The reproducibility of measurements of the eosinophil percentage, eosinophil cationic protein, tryptase, and methacholine PC(20) were similar (concordance correlation coefficients of 0.74, 0.81, 0.79, and 0.74, respectively), without any significant among-center effect. We conclude that sputum induction can be performed safely in subjects with moderate to severe asthma in multicenter clinical trials when carried out under carefully monitored conditions. Importantly, we demonstrate that measurement of markers of inflammation in induced sputum is as reproducible as methacholine PC(20) and should prove useful in the assessment of airway inflammation in multicenter clinical trials.

Aged↗
PubMed2001

The utility of peak flow, symptom scores, and beta-agonist use as outcome measures in asthma clinical research.

STUDY OBJECTIVES: Several methods of utilizing peak expiratory flow (PEF) and other markers of disease activity have been suggested as useful in the management of asthma. It remains unclear, however, as to which surrogate markers of disease status are discriminative indicators of treatment failure, suitable for use in clinical trials. DESIGN: We analyzed the operating characteristics of 66 surrogate markers of treatment failure using a receiver operating characteristic (ROC) curve analysis. PARTICIPANTS: Information regarding FEV(1), symptoms, beta(2)-agonist use, and PEF was available from 313 subjects previously enrolled in two Asthma Clinical Research Network trials, in which 71 treatment failures occurred (defined by a 20% fall in FEV(1) from baseline). INTERVENTIONS: None. MEASUREMENTS AND RESULTS: None of the measures had an acceptable ability to discriminate subjects with a > or % fall in FEV(1) from those without, regardless of the duration of the period of analysis or the criteria for test positivity employed. Areas under the ROC curves generated ranged from 0.51 to 0.79, but none were statistically superior. Sensitivity and specificity combinations were generally poor at all cutoff values; true-positive rates could not be raised without unacceptably elevating false-positive rates concurrently. CONCLUSIONS: Studies that seek to detect treatment failure defined by a significant fall in FEV(1) should not use such individual surrogate measures to estimate disease severity.

Adolescent↗
PubMed2000

The effect of polymorphisms of the beta(2)-adrenergic receptor on the response to regular use of albuterol in asthma.

Inhaled beta-adrenergic agonists are the most commonly used medications for the treatment of asthma although there is evidence that regular use may produce adverse effects in some patients. Polymorphisms of the beta(2)-adrenergic receptor (beta(2)-AR) can affect regulation of the receptor. Smaller studies examining the effects of such polymorphisms on the response to beta-agonist therapy have produced inconsistent results. We examined whether polymorphisms at codon 16 (beta(2)-AR-16) and codon 27 (beta(2)-AR-27) of the beta(2)-AR might affect the response to regular versus as-needed use of albuterol by genotyping the 190 asthmatics who had participated in a trial examining the effects of regular versus as needed albuterol use. During the 16-wk treatment period there was a small decline in morning peak expiratory flow in patients homozygous for arginine at B(2)-AR-16 (Arg/Arg) who used albuterol regularly. This effect was magnified during a 4-wk run out period, during which all patients returned to using as-needed albuterol, so that by the end of the study Arg Arg patients who had regularly used albuterol had a morning peak expiratory flow 30. 5 +/- 12.1 L/min lower (p = 0.012) than Arg/Arg patients who had used albuterol on an as needed basis. There was no decline in peak flow with regular use of albuterol in patients who were homozygous for glycine at beta(2)-AR-16. Evening peak expiratory flow also declined in the Arg/Arg patients who used albuterol regularly but not in those who used albuterol on an as-needed basis. No significant differences in outcomes between regular and as-needed treatment were associated with polymorphisms at position 27 of the beta(2)-AR. No other differences in asthma outcomes that we investigated occurred in relation to these beta(2)-AR polymorphisms. Polymorphisms of the beta(2)-AR may influence airway responses to regular inhaled beta-agonist treatment.

Adolescent↗
PubMed1999

Neutrophil elastase and elastase-rich cystic fibrosis sputum degranulate human eosinophils in vitro.

Neutrophils, eosinophils, and their proinflammatory constituents are important mediators of airway disease, and high levels of neutrophil proteases and eosinophil cationic protein (ECP) are found in sputum from patients with cystic fibrosis (CF). To investigate whether neutrophil proteases or CF sputum causes eosinophil degranulation, purified eosinophils from atopic asthmatic subjects were incubated for 2 h with neutrophil elastase, cathepsin G, and CF sputum, and the release of ECP was measured. We found that the percent release of ECP was higher after incubation with neutrophil elastase (10(-5) M) than with a buffer control [6.1 +/- 0.8 (SE) vs. 1.7 +/- 0.1%; P < 0.003] and represented >50% of the release caused by positive controls [Ca2+ ionophore A-23187 (5 x 10(-6) M) or serum-coated Sephadex beads]. The release of ECP after incubation with cathepsin G (2.3 +/- 0.2%) and CF sputum (6.2 +/- 2.0%) was also significantly higher than that with a buffer control (P < 0.05). Neutralization of free elastase activity with alpha1-proteinase inhibitor reduced the mean percent degranulation of eosinophils by neutrophil elastase by 50% (P = 0.0004) and by CF sputum by 75% (P = 0.02). Preincubation of eosinophils with cytochalasin B (10 mg/ml) and depletion of the incubation medium of Ca2+ also significantly attenuated degranulation of eosinophils incubated with purified free neutrophil elastase or CF sputum (P < 0.05). We conclude that neutrophil proteases, especially neutrophil elastase, and elastase-rich CF sputum cause degranulation of eosinophils in a mechanism partially dependent on Ca2+ and actin filaments.

Adult↗
PubMed1998

Inflammation, inflammatory mediators, and mediator antagonists in asthma.

Asthma is an inflammatory disease that involves mast cells, antigen-presenting cells, eosinophils, neutrophils, and TH2-lymphocytes. These cells produce a broad array of mediators and cytokines that lead to the bronchoconstriction, mucosal edema, mucus secretion, and bronchial hyperresponsiveness that characterize asthma. Current guidelines for therapy recommend that all patients whose asthma is more severe than mild intermittent receive chronic treatment with drugs that interrupt this inflammatory cascade. Corticosteroids have been the gold standard for treatment, but a greater understanding of the specific cells and mediators involved in the pathogenesis of asthma has led to more focused, specific therapy. Pharmacologic agents that interrupt the synthesis of action of leukotrienes, and monoclonal antibodies directed against intracellular adhesion molecules or immunoglobulin E are examples of the new generation of specific targeted therapy for use in asthma.

Administration, Inhalation↗
PubMed1998

Safety and clinical efficacy of zileuton in patients with chronic asthma.

Zileuton, a leukotriene pathway inhibitor used to treat asthma, improves lung function, relieves symptoms, and is well tolerated. The purpose of this 12-month, parallel-group, open-label study was to assess the efficacy of zileuton and evaluate liver function in patients treated with this drug (approximately 2% of patients treated with zileuton in controlled trials had reversible liver enzyme elevations). A total of 2,947 patients at 233 centers in the United States were randomly assigned in a 5:1 ratio to treatment with zileuton plus usual asthma care or usual asthma care alone. Efficacy variables included asthma exacerbations; need for alternative treatment, steroid rescue, emergency care, and hospitalizations; forced expiratory volume in 1 second (FEV1); and asthma symptom scores. The safety evaluation included measurement of alanine aminotransferase levels. Patients treated with zileuton had significantly fewer corticosteroid rescues (P < 0.001), required less emergency care (P < 0.05), had fewer hospitalizations, and had greater increases in FEV1 (P = 0.048). They also had significantly greater improvements in asthma symptoms. Increases in alanine aminotransferase levels to three times or more the upper limit of normal occurred in 4.6% of patients treated with zileuton and 1.1% of those receiving usual care (P < 0.001); most increases occurred during the first 2 to 3 months. Alanine aminotransferase levels decreased to less than two times the upper limit of normal or to baseline levels during zileuton treatment or after drug cessation. Jaundice or chronic liver disease did not develop in any patient. Adding zileuton to the therapeutic regimens of patients with asthma is likely to improve asthma control and lower utilization of healthcare resources.

Asthma↗
PubMed1997

An evaluation of colchicine as an alternative to inhaled corticosteriods in moderate asthma. National Heart, Lung, and Blood Institute's Asthma Clinical Research Network.

Colchicine demonstrates an array of anti-inflammatory properties of potential relevance to asthma. However, the efficacy of colchicine as an alternative to inhaled corticosteroid therapy for asthma is unknown. Five centers participated in a controlled trial testing the hypothesis that in patients with moderate asthma needing inhaled corticosteroids for control, colchicine provides therapeutic benefit as measured by maintenance of control when inhaled steroids are discontinued. Subjects were stabilized on triamcinolane acetonide (800 microg daily) and then enrolled in a 2-wk run-in during which all subjects took both colchicine (0.6 mg/twice a day) and triamcinolone. At the end of the run-in, all subjects discontinued triamcinolone and were randomized to continued colchicine (n = 35) or placebo (n = 36) for a 6-wk double-blind treatment period. The treatment groups were similar in terms of disease severity. After corticosteroid withdrawal, 60% of colchicine-treated and 56% of placebo-treated subjects were considered treatment failures as defined by preset criteria. No significant difference in survival curves was found between treatment groups (log rank = 0.38). Other measures, including changes in FEV1, peak expiratory flow, symptoms, rescue albuterol use, and quality of life scores, also did not differ between groups. Of note, subjects failing treatment had significantly greater methacholine responsiveness at baseline than did survivors (PC20, 0.81+/-1.38 versus 2.11+/-2.74 mg/ml; p = 0.01). An analysis of treatment failures suggested that the criteria selected for failure reflected a clinically meaningful but safe level of deterioration. We conclude that colchicine is no better than placebo as an alternative to inhaled corticosteroids in patients with moderate asthma. Additionally, we conclude that the use of treatment failure as the primary outcome variable in an asthma clinical trial where treatment is withdrawn is feasible and safe under carefully monitored conditions.

Administration, Inhalation↗
PubMed1997

The leukotriene receptor antagonist zafirlukast inhibits sulfur dioxide-induced bronchoconstriction in patients with asthma.

Inhalation of sulfur dioxide (SO2) causes bronchoconstriction in most people with asthma. To examine the role of leukotrienes in this response, the antagonism of SO2-induced bronchoconstriction by a single oral dose of the leukotriene receptor antagonist zafirlukast was assessed in a double-blind, placebo-controlled, two-period crossover trial in 12 subjects with mild-to-moderate asthma. Subjects had bronchial hyperresponsiveness, an FEV1 < or = 70% of predicted, and a positive response to inhaled SO2 (an 8-unit increase in specific airway resistance on inhaling an SO2 concentration of < or = 4 ppm (PC8SRaw). Subjects were treated with zafirlukast (20 mg) or placebo on two treatment days 5 to 14 d apart. Two and 10 hours after treatment, subjects inhaled SO2 (0.25, 0.5, 1.0, 2.0, 4.0, and 8.0 ppm) during eucapnic hyperventilation at 20 L/min. PC8SRaw was determined after each challenge. Blood samples were collected to assess zafirlukast plasma concentrations versus effect. PC8SRaw was significantly higher 2 h after zafirlukast compared with placebo (3.1 versus 1.5 ppm; p = 0.02) and remained higher 10 h after treatment with zafirlukast (2.7 versus 1.9 ppm; p = 0.09). An association was found between zafirlukast plasma concentrations and increases in PC8SRaw 10 h after treatment (p = 0.001). The safety profile of zafirlukast was not clinically different from placebo. A single 20-mg dose of zafirlukast attenuated SO2-induced bronchoconstriction. We conclude that S02-induced bronchoconstriction involves release of leukotrienes and that treatment with zafirlukast attenuates the bronchoconstrictor response.

Adult↗
PubMed1996

Comparison of regularly scheduled with as-needed use of albuterol in mild asthma. Asthma Clinical Research Network.

BACKGROUND: Inhaled beta-agonists are the most commonly used treatment for asthma, but data suggest that regularly scheduled use of these agents may have deleterious effect on the control of asthma. We compared the effects of regularly scheduled use of inhaled albuterol with those of albuterol used only as needed in patients with mild chronic, stable asthma. METHODS: In a multicenter, double-blind study, we randomly assigned 255 patients with mild asthma to inhale albuterol either on a regular schedule (126 patients) or only as needed (129 patients). The patients were followed for 16 weeks. RESULTS: The primary outcome indicator, peak expiratory air flow measured in the morning, did not change significantly during the treatment period in the scheduled (416 liters per minute after the run-in period and 414 liters per minute after the treatment period) or the as-needed (424 liters per minute at both times) treatment groups (P=0.71). There were no significant differences between the two groups in peak flow variability, forced expiratory volume in one second, the number of puffs of supplemental albuterol needed, asthma symptoms, asthma quality-of-life score, or airway responsiveness to methacholine. The statistically significant differences between the groups in evening peak flow and in the short-term bronchodilator response to inhaled albuterol were small and judged to be clinically unimportant. CONCLUSIONS: In patients with mild asthma, neither deleterious nor beneficial effects derived from the regular use of inhaled albuterol beyond those derived from use of the drug as needed. Inhaled albuterol should be prescribed for patients with mild asthma on an as-needed basis.

Administration, Inhalation↗
PubMed1996

Dog mastocytoma cells secrete a 92-kD gelatinase activated extracellularly by mast cell chymase.

Gelatinolytic metalloproteinases implicated in connective tissue remodeling and tumor invasion are secreted from several types of cells in the form of inactive zymogens. In this report, characterization of gelatinase activity secreted by the BR line of dog mastocytoma cells reveals a phorbol-inducible, approximately 92-kD, Ca2+ - and Zn2+ -dependent proenzyme cleaved over time to smaller, active forms. Incubation of cells with the general serine protease inhibitor, PMSF, prevented proenzyme cleavage and permitted its purification free of activation products. The NH2-terminal 13 amino acids of the purified mastocytoma progelatinase are 50-67% identical to those of human, mouse, and rabbit 92-kD progelatinase (gelatinase B; matrix metalloproteinase-9). Degranulation of mastocytoma cells using ionophore A23187 greatly accelerated proenzyme cleavage, suggesting that a serine protease present in secretory granules hydrolyzed the progelatinase to active fragments. To identify the activating protease, cells were coincubated with ionophore and a panel of selective serine protease inhibitors. Soybean trypsin inhibitor and succinyl-L-Ala-Ala-Pro-Phe-chloromethylketone, which inhibit mast cell chymase, prevented progelatinase activation. Inhibitors of tryptase and dog mast cell protease (dMCP)-3, i.e., aprotinin or bis(5-amidino-2-benzimidazolyl) methane (BABIM), did not. In further experiments using highly purified enzymes, mastocytoma cell chymase activated 92-kD progelatinase in the absence of other enzymes or cofactors; tryptase and dMCP-3, however, had no effect. These data demonstrate that dog mastocytoma cells secrete a metalloproteinase related to progelatinase B that is directly activated outside of the cell by exocytosed chymase, and provide the first demonstration of a cell that activates a matrix metalloproteinase it secretes by cosecreting an activating enzyme. In mastocytomas, this pathway may facilitate tumor invasion of surrounding tissues, and in normal mast cells, it could play a role in tissue remodeling and repair.

Amino Acid Sequence↗
PubMed1996

Authentic 17 kDa tumour necrosis factor alpha is synthesized and released by canine mast cells and up-regulated by stem cell factor.

BACKGROUND: Previous studies have suggested varying molecular weights for mast cell derived tumour necrosis factor alpha (TNF alpha ) and little data exist upon the factors which may regulate the control of this cytokine in these cells. OBJECTIVE: To determine the molecular weight of canine mastocytoma-derived TNF alpha, to determine whether it is pre-formed within the granule and whether is expression could be up-regulated by stem cell factor (SCF). METHODS: Molecular sizing was assessed by immunoblot. The cellular localization of the TNF alpha was determined by immunocytochemistry before and after stimulation by A23187 and passive sensitization. Subcellular localization was performed by immunogold immunocytochemistry. Changes in the level of mastocytoma mRNA for TNF alpha in response to stimulation with SCF or fibroblast conditioned media for up to 12 weeks were studied using Northern analysis and changes in the level of TNF alpha protein expression on immunoblot and immunocytochemistry. RESULTS: Mast cells contained authentic 17 kDa TNF alpha as identified by immunoblotting. Immunocytochemical studies demonstrated preformed TNF alpha which was released by stimulation with antigen after passive sensitization, or by the calcium ionophore A23187. Further confirmation of the preformed nature of this TNF alpha was provided by immunogold electron microscopy which localized this cytokine to the granule of the inactive mast cell. Northern blotting revealed a constitutive message for TNF alpha, which increased in response to fibroblast conditioned media (FCM) and to recombinant human SCF. Immunocytochemical studies of mast cells cultured long-term with FCM or with recombinant SCF showed increased expression of TNF alpha over the course of 12 weeks incubation with these stimuli. CONCLUSION: Mastocytoma derived-TNF alpha is a preformed, granule-associated 17 kDa cytokine which is released on stimulation with A23187 or passive sensitization. It is up-regulated by stem cell factor and by FCM over the course of 12 weeks.

Animals↗
PubMed1993

In vitro histamine release induced by magnetic resonance imaging and iodinated contrast media.

RATIONALE AND OBJECTIVES: To investigate the mechanism of anaphylactoid reactions to contrast media, in vitro histamine release induced by magnetic resonance imaging, and iodinated contrast agents was examined in a dog mastocytoma cell line. METHODS: Two gadolinium (Gd)-based magnetic resonance contrast agents, Gd diethylenetriamine pentaacetic acid (Gd-DTPA), dimeglumine, and Gd-bismorpholide, and two iodinated contrast agents, diatrizoate meglumine and iohexol, were incubated with histamine-containing canine mastocytoma cells. Release of histamine into the supernatant was determined at various contrast-medium concentrations after incubation at 37 degrees C for 30 minutes. RESULTS: Iodinated and Gd-based contrast agents caused release of histamine from mastocytoma cells at similar concentrations (50-150 mM). Mannitol, an osmotic stimulus, caused release of histamine only at concentrations greater than 1,000 mM. CONCLUSIONS: Histamine release from canine mastocytoma cells does not appear to be solely due to osmotic effects, but results from direct stimulation by contrast media. For all agents examined, the concentration at which in vitro histamine release occurs far exceeds the serum contrast media concentration expected in routine clinical application. Direct release of histamine from mast cells does not completely explain the pathogenesis of idiosyncratic anaphylactoid responses to contrast media.

Anaphylaxis↗
PubMed1993

Heparin inhibits histamine release from canine mast cells.

To determine the role of heparin in mast cell exocytosis, we studied the effect of heparin on histamine release induced by compound 48/80 or calcium ionophore A23187 in canine mastocytoma cells (BR). Heparin caused concentration-dependent inhibition of compound 48/80-induced histamine release from mast cells (n = 4; P < 0.05) with a mean inhibitory concentration of 0.14 +/- 0.01 U/ml (mean +/- SE). Mean maximal inhibition was 69.3 +/- 2.0%. In contrast, heparin had no effect on calcium ionophore A23187-induced histamine release. Although benzyl alcohol, a preservative of pharmaceutical heparin, had no effect, purified heparin produced a similar inhibitory effect on compound 48/80-induced histamine release (n = 4; P < 0.05). The inhibitory effect of heparin on histamine release was rapid and was eliminated by washing cells. Dextran sulfate, a polysaccharide with negative charge density, produced a similar inhibitory effect on compound 48/80-induced histamine release (n = 4; P < 0.05). We conclude that heparin inhibits compound 48/80-induced exocytosis in mast cells probably by its negative charge density.

Animals↗
PubMed1993

Mitogen-inducible prostaglandin G/H synthase is expressed in canine mastocytoma cells.

A mitogen-inducible prostaglandin G/H synthase (PGHS-2 or cyclooxygenase-2) has recently been cloned from chicken and mouse fibroblasts. This protein is distinct from classic prostaglandin G/H synthase (PGHS-1 or cyclooxygenase-1) but has a similar enzymatic activity. Because PGHS-1 is a rate-limiting enzyme in the synthesis of prostaglandins, PGHS-2 may also play an important role in prostaglandin production. To examine whether PGHS-2 is induced by phorbol ester in mast cells, we studied mRNA expression of PGHS-2 and also measured prostaglandin D2 (PGD2) production when canine mastocytoma cells were incubated with phorbol myristate acetate (PMA). PGHS-2 mRNA was induced by PMA, with a maximal induction after 4 h of incubation with 10 nM PMA. There was concentration-dependent production of PGD2 after incubation with PMA. In contrast, PGHS-1 mRNA was expressed in resting cells, and the expression of PGHS-1 mRNA was down-regulated by PMA. Dexamethasone inhibited PMA-induced mRNA expression of PGHS-2 and PGD2 production. Aspirin had no effect on mRNA expression of PGHS-2 but inhibited PGD2 production. In conclusion, PGHS-2 is induced by phorbol ester in canine mast cells. We speculate that PGHS-2 may be important in airway inflammation in which mast cells are activated.

Animals↗