Effects of sodium cromoglycate and nedocromil sodium on histamine secretion from human lung mast cells

Delayed anti-inflammatory action of nedocromil sodium in the rat paw is dependent on de novo protein synthesis

Nedocromil sodium is commonly suggested to reduce allergic inflammation by inhibiting mediator release from mast cells. However, nedocromil also exhibits a wide range of additional anti-inflammatory activities, including inhibition of increased vascular permeability induced by individual mediators such as histamine. In the present study, we have further characterized the mode of action of nedocromil in a rat model for hind paw edema. Mast cell-dependent edema was induced with compound 48/80 (edema response mainly due to 5-hydroxytryptamine release), and direct mediator-induced plasma extravasation was evoked by exogenous 5-hydroxytryptamine (both agents injected locally). Local pretreatment with nedocromil for 20 min dose-dependently inhibited the edema evoked by compound 48/80 more effectively than that induced by 5-hydroxytryptamine. However, after 2 h pretreatment, both the 5-hydroxytryptamine-and compound 48/80-induced edema responses were inhibited to approximately the same extent by a range of concentrations of nedocromil, as well as by dexamethasone. Local inhibition of RNA/protein synthesis with actinomycin-D abolished the effects of both dexamethasone and nedocromil (2 h local pretreatment). We thus conclude that nedocromil can produce an 'anti-exudative' effect that is independent of inhibition of mast cell mediator release, is slow in onset, and requires de novo protein synthesis.

Modulations of histamine release from mast cells by interleukin-2 is affected by nedocromil sodium

We have previously demonstrated that histamine release from immunologically activated mast cells (MC) is enhanced by their preincubation (1 h) with interleukin-2(IL-2), and that IL-2 induces slow-chronic histamine release by MC in long-term cultures (6 days). In the present study we assessed whether nedocromil sodium can interfere with IL-2 modulation of MC histamine release. IL-2 enhancing effects nedocromil sodium activity were studied in cocultures of rat peritoneal MC with 3T3 fibroblasts (MC/3T3). MC/3T3 were preincubated for 1 h with IL-2 (50 micrograms/ml) and activated with either rabbit anti-rat IgE or compound 48/80. In chronic experiments MC/3T3 were long-term (5-6 days) incubated with IL-2 (50 micrograms/ml). Nedocromil sodium was used at 10(-5) M. MC activation both when added during the preincubation period (no tachyphylaxis was present) and when added together with the MC activators (30-50% inhibition). Washing out IL-2 before addition of the anti-IgE antibodies did not affect its histamine-release enhancing activity. Removal of nedocromil sodium before addition of the stimulus completely abrogated its effect. Continuous presence of IL-2 in the culture medium enhanced spontaneous histamine release by 37% and this effect was completely abolished in the presence of nedocromil sodium. Furthermore, nedocromil sodium decreased MC basal histamine release by 23% in long-term cocultures. Since IL-2 is known to be elevated in some pathological conditions, our results show that nedocromil sodium inhibits MC activation in an in vitro system which may represent a close resemblance to the in vivo allergic response.

Regulation of histamine release from human bronchoalveolar lavage mast cells by stem cell factor in several respiratory diseases

We investigated the effects of stem cell factor (SCF) on histamine release (HR) from human bronchoalveolar lavage (BAL) mast cells. BAL cells were recovered from lavage performed in patients undergoing clinical bronchoscopy. SCF (0.02-20 ng/ml), which is by itself a poor secretagogue (mean +/- SEM HR: 3.7 +/- 0.9%; n = 27), strongly enhanced HR induced by anti-IgE in a concentration-related manner. Significant potentiation began at 0.2 ng/ml (30 +/- 10%; p < 0.05; n = 12) and reached a plateau at 2 ng/ml (40 +/- 10%; P < 0.01 at 2 ng/ml and 45 +/- 10%; P < 0.01 at 20 ng/ml; n = 12). In contrast, SCF failed to enhance HR induced by calcium ionophore A23187. Among the BAL cell samples initially unresponsive to anti-IgE (55% of samples), 36% (10/28) were converted to responders if the cells were shortly preincubated with SCF. In 25% of samples (7/27), SCF (20 ng/ml) caused direct HR of 10 +/- 2.1%. The mast cells which released histamine when challenged with SCF also secreted higher levels of histamine in response to anti-IgE and calcium ionophore than those nonresponsive to SCF. While interleukin (IL)-3 and IL-5 (20 ng/ml) were unable to modulate immunologic HR, GM-CSF (20 ng/ml) produced significant potentiation (P < 0.05), which was, however, smaller than that observed with SCF.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical experience with Tilavist: an overview of efficacy and safety

A programme of clinical studies was carried out to determine the basic efficacy and safety of 2% nedocromil sodium eye drops (Tilavist) in treating allergic conjunctivitis, in 2,905 patients from 3-76 years of age. Results of all the double-masked placebo comparative studies completed to date-five in vernal keratoconjunctivitis (VKC), five in perennial (PAC) and 16 in seasonal allergic conjunctivitis (SAC)-have been assessed in a statistical overview analysis. Nedocromil sodium, administered four times daily to 153 patients with VKC, was significantly more effective than placebo (155 patients) and in the clinicians' opinion gave good control in 76% of cases, compared with 46% for placebo (p < 0.001). Patients with chronic symptoms of PAC also responded better to nedocromil sodium given four times daily (n = 146) rather than twice daily (n = 86), and significantly more patients (p < 0.001) were effectively controlled by four times daily treatment with nedocromil sodium (72%) than with placebo (47%; n = 156). Twice-daily dosage with nedocromil sodium (n = 677) was adequate for SAC, however, and the treatment was statistically better than placebo (p < 0.01-p < 0.001) whether dosed twice or four times daily. Speed of action was assessed in seven SAC studies in which 79% of all patients (n = 295) using nedocromil sodium had experienced relief of symptoms when questioned, half of them within 15 minutes and 74% during the first hour after dosing. Test treatments were well-accepted by both adults and children, and there were no major adverse events. Minor irritations reported more frequently with nedocromil sodium than placebo were stinging or burning of the eyes on application of the drops and a distinctive taste, noted by 5% of the active treatment group (n = 1,552).

Effect of sodium metabisulphite on bronchial blood flow in conscious sheep: pharmacological modulation

1. Sodium metabisulphite (MBS) can induce bronchoconstriction in patients with asthma. We investigated the effects of MBS aerosol on bronchial blood velocity (Vbr) and pulmonary resistance in intubated conscious sheep. 2. Bronchial blood velocity was measured by implanting a 20 MHz ultrasonic Doppler flow probe on the common bronchial branch of the bronchoesophageal artery. 3. Inhaled MBS induced a dose-dependent, transient increase in Vbr lasting for a few minutes without any changes in aortic and pulmonary artery pressures. There was some tachyphylaxis of the Vbr response to successive inhalations of MBS. 4. The cholinoceptor antagonist, ipratropium bromide and the H1 and H2 histamine antagonists, chlorpheniramine and cimetidine, had no significant effect on MBS-induced increase on Vbr. The loop diuretic, frusemide, and the anti-inflammatory drug, nedocromil sodium, which both inhibit MBS-induced bronchoconstriction in patients with asthma, were also without effect. 5. We conclude that MBS induces bronchial vasodilatation in conscious sheep, and that this effect is not dependent on the release of histamine or other mediators, or an activation of cholinergic pathways.

Effects of nedocromil sodium on bronchospasm and HS-NCA release induced by allergen inhalation in asthmatic patients

The aim of this study was to assess the ability of nedocromil sodium (NS) to prevent the immediate asthmatic reaction and the increase in the serum level of heat stable neutrophil chemotactic activity (HS-NCA) induced by antigen inhalation. In a double-blind, cross-over study, 13 atopic subjects affected with seasonal asthma underwent a bronchial provocation test with a preselected dose of grass pollen allergen (enough to cause a decrease of > or = 20% in FEV1:FEV1 PD20) after pre-treatment with 4 mg NS or placebo. Serum samples were withdrawn from 11 subjects for HS-NCA determination. After NS administration the decrease in FEV1 was significantly less than after placebo administration at all time points after challenge (2 min P = 0.0004; 7 min, P = 0.0005; 17 min P = 0.0002 and 27 min P = 0.0005). The percentage increase in HS-NCA was significantly higher after placebo than after NS inhalation, both 10 (P = 0.0048) and 20 (P = 0.0068) min after challenge. Our study confirms previous investigations, showing that NS inhibits the immediate asthmatic response to allergen inhalation in atopic, asthmatic subjects and moreover it shows that this drug prevents in vivo the increase of the serum HS-NCA. This last finding has not been previously reported.

Nedocromil sodium and sodium cromoglycate in patients aged over 50 years with asthma

We conducted a double-blind parallel-group study to compare the efficacy of inhaled nedocromil sodium and inhaled sodium cromogylcate in patients aged 50 years or over with asthma. Seventy-seven patients were randomized, 38 to receive nedocromil sodium (4 mg q.d.s.) and 39 to receive sodium cromoglycate (10 mg q.d.s.) over a 16-week period. Eight patients withdrew from the study. Both patient groups showed a reduction in inhaled bronchodilator usage during the treatment period. No statistically significant differences were seen in diary card PEF recordings or symptom scores. Both clinic PEF and FEV1 were significantly greater (P < 0.05) in the sodium cromoglycate group at week 12. Patients considered the treatment to be very or moderately effective in 59% of the nedocromil sodium group and 50% of the sodium cromoglycate group. Thus, the study suggests that there is no difference in response to nedocromil sodium or sodium cromoglycate in this older group of patients with asthma who are already on moderate doses of inhaled steroids.

Albuterol and nedocromil sodium affect airway and leukocyte responses to allergen

We investigated the effects of inhaled nedocromil sodium and albuterol administered prior to allergen challenge in the late asthmatic response (LAR) and circulating cells in a double-blind placebo-controlled study. An additional control day (no allergen) was included to determine diurnal variation. On the control day no change in airway caliber occurred, but a diurnal increase in the numbers of all circulating leukocytes except basophils was seen. Placebo premedication followed by allergen challenge caused both an early asthmatic response (EAR) and a late asthmatic response (LAR). Following allergen challenge after placebo the diurnal increase in eosinophils at 8 h was abolished, and elevated eosinophil and basophil counts were observed at 24 h. Nedocromil sodium attenuated both the EAR and the LAR, and it restored the eosinophil and basophil responses toward normal. Albuterol abolished the EAR and attenuated the LAR and the 24-h increase in circulating basophils. No changes in lymphocyte subpopulations were seen. We conclude that during the LAR there is entrainment of eosinophils within the lung, with a subsequent bone marrow response increasing peripheral populations of eosinophils and basophils. Nedocromil sodium may act by inhibiting the recruitment of inflammatory cells, particularly eosinophils, possibly by affecting the generation of cytokines and the expression of leukocyte-specific adhesion molecules. Albuterol may have similar actions as shown by an effect on basophils.

Nedocromil sodium. An updated review of its pharmacological properties and therapeutic efficacy in asthma

Nedocromil sodium, the disodium salt of a pyranoquinoline dicarboxylic acid, has anti-inflammatory properties in vitro, in animal models of asthma, and in humans, as evidenced by inhibition of inflammatory cell activation and mediator release, early and late allergen-induced bronchoconstriction and airway hyperresponsiveness. Recent therapeutic trials confirm the safety and efficacy of inhaled nedocromil sodium as adjunctive therapy in adult patients whose asthma is not adequately controlled by beta-agonists alone. Nedocromil sodium has also been shown to improve symptoms when added to existing treatment with methylxanthines and corticosteroids. Some studies show nedocromil sodium to be successful replacement therapy for methylxanthines, in addition to enabling a modest reduction in inhaled corticosteroids in some patients. Thus, nedocromil sodium may be suitable in patients with asthma as an adjunct to existing therapy, as an alternative to regularly administered oral and inhaled beta-agonists and oral methyl-xanthines, and potentially, to low dose inhaled corticosteroids as maintenance therapy in patients with mild to moderate asthma being considered for corticosteroid therapy.

The effect of nedocromil sodium on histamine responsiveness in clinically stable asthmatic children

A double-blind, randomized, placebo-controlled, parallel-group study was undertaken in 120 clinically stable asthmatic children (aged 6-19 years) to determine the ability of 8 weeks of treatment with nedocromil sodium (4 mg, three times a day) to reduce the level of histamine responsiveness. Despite the subjects being clinically stable and reporting few asthma symptoms, approximately one-third had abnormal pulmonary function on enrollment into the study. Statistically significant increases in pulmonary function were seen in the group treated with nedocromil sodium but not in the control group (p = 0.01). Furthermore, 52% of the individuals with abnormal pulmonary function returned to normal following treatment with nedocromil sodium compared to 11% of those with abnormal pulmonary function who received placebo. However, there were no differences in the level of histamine responsiveness between the two treatment groups at baseline or after 4 or 8 weeks of treatment with nedocromil sodium or placebo. These data suggest that the level of histamine responsiveness is not intimately related to the level of asthma control in children.

Nedocromil sodium inhibits the airway response to hyperosmolar challenge in patients with asthma

We studied 16 asthmatic subjects sensitive to changes in airway osmolarity to determine whether nedocromil sodium has any effect on airway narrowing caused by hypertonic saline challenges. Nedocromil sodium (10 mg) or its vehicle was inhaled 10 min before a challenge with ultrasonically nebulized 4.5% NaCl. FEV1 was measured before challenge and 1 min after each challenge period of 0.5, 1, 2, 4, 8, 8 and 8 min. The challenge was stopped when there was a 20% fall in FEV1 from baseline or after the final challenge period. We measured airway sensitivity, that is, the provoking dose of 4.5% NaCl required to induce a 20% reduction in FEV1 (PD20FEV1) and calculated the fold difference in PD20FEV1 after the intervention. After inhaling nedocromil sodium there was a 3.95-fold improvement in PD20 (p < 0.001) when compared with the vehicle day. After pretreatment with nedocromil sodium two of the 16 subjects were completely protected against 4.5% NaCl challenge, and six developed a plateau in their response. We conclude that nedocromil sodium is effective in reducing airway narrowing in response to 4.5% NaCl challenge in asthmatic subjects, and it appears to be unique in its ability to produce a plateau in response to acute administration of a drug before a bronchial challenge.

Nedocromil sodium modulates the function of long-term rat peritoneal mast cell cultures

Long-term rat peritoneal mast cell (MC) cultures consisting of MC co-cultured with 3T3 fibroblasts (MC/3T3) were employed to study the effects of repeated and prolonged incubation with nedocromil sodium (10(-3) and 10(-5) M) on MC activation. When nedocromil sodium was added simultaneously with compound 48/80 to MC/3T3 on the first day of the experiment, it inhibited histamine release to the same extent as when added to the cultures a week later upon rechallenge. In other experiments activated MC/3T3 were incubated with nedocromil sodium for a week and on the last day of the experiment fresh nedocromil sodium was added simultaneously with compound 48/80. Under these conditions the drug was as potent in inhibiting histamine release from the activated MC as it was in cultures incubated for a week with medium alone. In addition, preincubation of naive MC with nedocromil sodium for two days inhibited histamine release from these cells when activated for the first time. Salbutamol (10(-3) and 10(-5) M) exhibited a similar inhibitory effect to nedocromil sodium upon simultaneous incubation with MC/3T3. However, prolonged incubation of salbutamol with MC/3T3 cultures resulted in tachyphylaxis. We conclude that nedocromil sodium is an effective MC stabilizing drug since it similarly inhibits histamine release from both primarily and secondarily challenged MC. Moreover this drug does not lose its efficacy upon prolonged incubation with MC.

Anti-inflammatory drugs in the treatment of allergic disease

The treatment of asthma is undergoing significant change with an emphasis on anti-inflammatory therapy. While glucocorticoids are the most potent anti-inflammatory agent, certain patients fail to respond. These patients may be candidates for alternative anti-inflammatory therapy, such as troleandomycin, methotrexate, gold, hydroxychloroquine, or dapsone. In addition, the application of immunomodulator therapy, such as intravenous gamma globulin or cyclosporine, may be useful.

The effect of respiratory manoeuvres and pharmacological agents on the pharmacokinetics of nedocromil sodium after inhalation

1. Eight healthy subjects inhaled nedocromil sodium from a metered-dose inhaler using a standardised inspiratory technique. Blood samples were taken for up to 270 min after inhalation for radioimmunoassay of plasma nedocromil sodium concentrations. 2. To investigate the possibility that respiratory manoeuvres can alter the absorption of the drug from the lungs, on the first (control) study day at 70 min after dosing, subjects performed nine forced expiratory manoeuvres over a 3 min period. At 110 min after dosing, subjects took a slow, full inspiration with a 30 s breath-hold, and at 150 min after dosing the subjects performed one single forced expiration. 3. On the second study day, subjects inhaled methoxamine, 0.15 mg kg-1 of a 20 mg ml-1 solution at 60 min after dosing, and the study continued as above. On the third day, subjects repeated the sequence of respiratory manoeuvres, after having taken phenoxymethyl penicillin and probenecid by mouth for 48 h. 4. Both multiple forced expirations and the deep inspiration with breath-hold produced significant increases in the absorption of nedocromil sodium. Inhaled methoxamine did not alter airway calibre or the response to the respiratory manoeuvres. Probenecid, but not penicillin, was detected in the subjects' plasma, and had the effect of increasing the rise in plasma nedocromil sodium concentrations after the multiple forced expirations when compared with the control day. 5. These data suggest that disruption of epithelial tight junctions induced by the respiratory manoeuvres leads to enhanced paracellular transport of nedocromil sodium into the draining circulation of the airways and alveoli.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition profiles of sodium cromoglycate and nedocromil sodium on mediator release from mast cells of human skin, lung, tonsil, adenoid and intestine

We have studied an aspect of the functional heterogeneity of human mast cells, namely responsiveness to the inhibitory effects of sodium cromoglycate and nedocromil sodium. The effects of these drugs were examined on the release of histamine and PGD2 from mast cells of human skin, lung, tonsils, adenoids and intestine. A high concentration, 1000 microM, of sodium cromoglycate was required to significantly inhibit histamine release from lung and tonsillar mast cells. Nedocromil sodium, 1000 microM, was more effective than sodium cromoglycate against histamine release from lung, tonsillar and adenoidal cells. Both compounds showed tachyphylaxis in lung and tonsillar mast cells but not in adenoidal and intestinal mast cells. In contrast, in intestinal mast cells, the effect of nedocromil sodium was weaker and more variable than sodium cromoglycate. Skin mast cells differed from mast cells of the other anatomical sites in being unresponsive to sodium cromoglycate and nedocromil sodium. Our results confirm that high concentrations of sodium cromoglycate and nedocromil sodium are required to achieve even modest inhibition of mediator release from human mast cells under in vitro conditions. Notwithstanding this, the results also indicate that differences exist among skin, lung, tonsillar, adenoidal and intestinal mast cells with respect to their sensitivity to sodium cromoglycate and nedocromil sodium, thus extending our knowledge of functional heterogeneity within the human mast cell populations.

In vivo release of 15-HETE and other arachidonic acid metabolites in nasal secretions during early allergic reactions

The purpose of this study is to examine the "in vivo" release of 15-HETE and other arachidonic acid metabolites in nasal secretions following a challenge with "Dermatophagoides Pteronyssinus" in patients with allergic rhinitis and non-allergic controls. In addition, we examine the effects of a membrane stabilizer, such as sodium cromoglycate, on these metabolites. Thirteen allergic subjects and seven healthy controls are studied. 15-HETE, peptide leukotrienes, LTB4, PGD2, PGE2 and PGF2 alpha levels are evaluated before and after nasal challenge in sodium cromoglycate treated and untreated subjects. This study provides "in vivo" evidence that the pathophysiological responses to nasal antigen challenge could be related to the release of 15-HETE as well as other arachidonic acid metabolites, mainly arising from the lipoxygenase pathway.

Mast cell activity in experimental allergic encephalomyelitis

The number and functional reactivity of peritoneal mast cells (MCs) were evaluated in rats with experimental allergic encephalomyelitis (EAE). Cells were counted following staining with toluidine blue and activation was measured by B-hexosaminidase (B-hex) release. The number of detectable MCs and their capacity to release B-hex decreased significantly by 40 and 65%, respectively, as compared with normal controls just prior to the onset of clinical signs. These values returned to normal on clinical recovery. Preliminary data on MC counts performed on histological sections of rat brains with EAE suggested a similar pattern of response, i.e., an early decrease prior to disease onset with subsequent normalization on recovery. In an attempt to modify the course of EAE, rats were treated with the MC stabilizing agent nedocromil or with the MC activating agent, compound 48/80. Nedocromil induced a slight delay in the onset of EAE, but only when administered at the time of EAE induction. Compound 48/80 did not seem to affect the clinical course of the disease. Our results suggest that MCs are involved in the pathogenesis of EAE and may contribute to the induction of the disease rather than to the effector phase and its clinical expression.

Biological properties of human skin mast cells

Mast cells and basophils, although sharing many constitutive properties, are quite distinct in their development, functions and biological properties. Mast cell granules are composed of a macromolecular matrix of proteoglycan and neutral protease of which heparin and tryptase, respectively, are predominant. The distribution of the other major neutral protease, chymase, allows human mast cell subpopulations to be subdivided immunocytochemically. All human mast cells respond to IgE-dependent stimulation with the secretion of the preformed mediator, histamine, and the newly generated lipid-derived eicosanoids PGD2 and LTC4. Although amounts of these products vary between mast cells dispersed from different tissues, it is uncertain whether this reflects true heterogeneity. Mast cells of the human skin, but not those of other tissues, are sensitive to stimulation by substance P, compound 48/80 and other basic non-immunological stimuli. The mechanism of mediator secretion induced by these agents is distinct from that induced by IgE-dependent stimulation. However, the morphological characteristics of degranulation are similar, suggesting that the distinct biochemical pathways merge into a common pathway before effecting degranulation.

Neutrophils and mast cells: nedocromil sodium inhibits the generation of neutrophil-derived histamine-releasing activity (HRA-N)

The effect of nedocromil sodium on the generation of neutrophil-derived histamine-releasing activity (HRA-N) from human peripheral blood neutrophils and on the secretory effects of HRA-N and anti-IgE on rat basophil leukemia (RBL) cells was studied. Nedocromil sodium caused dose-related inhibition of HRA-N generation by human neutrophils (10(-7) to 10(-4) mol/L; inhibitory concentration of 50%, 1.5 x 10(-8) mol/L). In contrast, the presence of nedocromil sodium had no effect on HRA-N-mediated serotonin release from RBL cells. In five experiments, with one crude and four partially purified HRA-N preparations, serotonin release from RBL cells exposed to native HRA-N or HRA-N in the presence of nedocromil sodium (10(-4) mol/L) was 28% +/- 6% and 26% +/- 5%, respectively. Similar results were found with all concentrations of nedocromil sodium studied. Preincubation of RBL cells with nedocromil sodium (10(-4) mol/L) for 0 to 60 minutes also did not affect HRA-N-mediated serotonin release. Likewise, nedocromil sodium (10(-7) to 10(-4) mol/L) had no effect on anti-IgE-induced serotonin release from RBL cells. In 10 experiments, anti-IgE alone or in the presence of nedocromil sodium (10(-4) mol/L) induced 32% +/- 6% and 32% +/- 5% serotonin release, respectively. Preincubation of RBL cells with nedocromil sodium before anti-IgE exposure had no further effect. This is the first study of pharmacologic manipulation of the generation of a histamine-releasing factor. It is hypothesized that one possible mechanism whereby nedocromil sodium protects against asthma and allergic rhinitis is through inhibition of HRA-N generation.

Nedocromil sodium modulates nonadrenergic, noncholinergic bronchoconstrictor nerves in guinea pig airways in vitro

Nonadrenergic, noncholinergic (NANC) neural bronchoconstrictor responses in guinea pig airways are due to the release of tachykinins from sensory nerves. We have performed an in vitro study using electrical field stimulation (EFS; 40 V, 0.5 ms, 8 Hz for 20 s) in guinea pig bronchi to investigate the effect of nedocromil sodium (NS) on NANC bronchoconstrictor responses. NS inhibited NANC bronchoconstriction in bronchi in a concentration-dependent manner, with a maximum inhibition of 40 +/- 4% (p less than 0.001, n = 6) at 100 microM. Cromolyn sodium, however, produced only 9 +/- 8% inhibition at the same molar concentration (p less than 0.05). NS did not affect the contractile response to substance P, nor did it modulate the cholinergic bronchoconstrictor response to EFS in tracheal smooth muscle. These results indicate that NS may modulate the release of tachykinins from airway sensory nerves.

Long-term drug treatment of asthma in children

In this short review the pharmacologic and clinical effect of antiasthma drugs in children that is, beta 2-agonists, theophylline, anticholinergics, disodiumcromoglycate/nedocromil sodium, and inhaled corticosteroids are described. Furthermore, a medication plan for maintenance treatment is presented.

Protection by nedocromil sodium of active immunization-induced bronchopulmonary alterations in the guinea pig

The effect of nedocromil sodium on PAF-acether- and antigen-induced bronchoconstriction (BC) and mediator release in lungs from actively sensitized guinea pigs and on the eosinophil content of bronchoalveolar lavage (BAL) was investigated. Guinea pigs were actively sensitized by two subcutaneous injections of 10 micrograms ovalbumin in 1 mg AI(OH)3 at 2-wk intervals. One week after the second (booster) injection, the lungs were removed, perfused in the absence or presence of indomethacin, and challenged at 10-min intervals with PAF-acether (1 and 100 ng) and with ovalbumin (1 micrograms). No inhibition of PAF-acether- and antigen-induced BC or mediator release from sensitized lungs was observed when nedocromil sodium (10 microM) was added directly to the buffer solution. By contrast, when guinea pigs were treated for 1 wk before the experiment with nedocromil sodium (30 mg/kg per day), BC and the release of leukotrienelike material (but not of thromboxane B2) to 1 ng PAF-acether were reduced by around 50% (p less than 0.05) and 62% (p less than 0.05), respectively. No inhibition was observed for 100 ng PAF-acether and 1 micrograms ovalbumin. Furthermore, nedocromil sodium markedly impaired histamine secretion induced by both PAF-acether and antigen administration. Nedocromil sodium did not affect the titers of circulating ovalbumin-specific immunoglobulin G, as detected by an enzyme-linked immunosorbent assay. The 1-wk treatment with nedocromil sodium also reduced markedly the proportion of eosinophils in the BAL of sensitized guinea pigs, whereas it was ineffective when injected once subcutaneously at the dose of 30 mg/kg 2 h before the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

Mast cells from human colonic mucosa and submucosa/muscle: a comparison with human lung mast cells

The functional properties of enzymically dispersed mast cells from human lung parenchyma, colonic mucosa and colonic submucosa/muscle were compared. In general, the cells responded in a similar fashion to the histamine releasing action of a variety of immunological and non-immunological stimuli. However, some differences were observed in their responses to anti-allergic compounds. In total, these data indicate that there are subtle variations between human colonic and pulmonary mast cells but that these differences are much less sharply defined than in the rodent.

The protective efficacy of inhaled, oral and intravenous nedocromil sodium against adenosine-5'-monophosphate-induced bronchoconstriction in asthmatic volunteers

We have investigated the pharmacokinetics and pharmacodynamics of nedocromil sodium administered by inhalation (4 mg), by mouth (80 mg) and by intravenous infusion (6 micrograms/kg) against adenosine-5'-monophosphate (AMP) induced bronchoconstriction in 9 mildly asthmatic subjects. Their mean baseline FEV1 was 83.8% of the predicted value, geometric mean (GM) PC20 FEV1 histamine 0.33 mg/ml (range 0.03-4.0), and GM PC50 baseline sGaw AMP 4.37 mg/ml (range 0.158-26.38). Blood collected at intervals for up to 4 h after drug administration was assayed for nedocromil sodium by radioimmunoassay, to derive the maximal drug concentration (Cmax), concentration at time of AMP challenge (Cchall), area under the plasma concentration-time curve (AUC), and the mean residence time (MRT). Airways responsiveness to inhaled AMP was assessed before and after administration of nedocromil sodium by each of the three routes of administration, and the protective efficacy was expressed as the concentration ratio (CR). AMP challenge was carried out 60 min after inhaled nedocromil sodium, 120 min after drug ingestion and 75 min after the start of the intravenous infusion. The GM PC50 sGaw AMP determined after inhaled, oral and intravenous nedocromil sodium was 28.84, 7.24 and 7.94 mg/ml respectively. For the group as a whole, nedocromil sodium by the oral or intravenous routes produced little overall protection against AMP (CR increasing by 0.75 and 0.88 doubling dilutions respectively). However, with inhaled drug, the concentration response curve with AMP was displaced to the right achieving an increased CR of 2.71 doubling dilutions. No relationship could be established between baseline FEV1, and AUC, Cmax or Cchall, or between these indices and the protective efficacy for the drug.(ABSTRACT TRUNCATED AT 250 WORDS)