Nedocromil sodium inhibits the increase in airway reactivity induced by platelet activating factor in humans

To investigate the effect of nedocromil sodium on changes in airway reactivity to methacholine induced by platelet activating factor, we studied 12 nonasthmatic, nonatopic subjects (24 to 41 years) in a double-blind trial. The FEV1 and airflow at 30 percent of vital capacity from a partial forced expiration (V30p) were used to assess changes in airway caliber. Two concentration-response curves to doubling concentrations of MCh (from 0.3 mg/ml) were performed 48 h apart. The concentrations of MCh causing a 20 percent fall in FEV1 (PC20FEV1) or a 40 percent fall in V30p (PC40V30p) were calculated. After the first MCh challenge, subjects were matched by airway reactivity and randomly assigned to nedocromil sodium (two puffs qid 2 mg/puff) or placebo treatment. Two days after the second MCh challenge, PAF was inhaled, and changes in airway caliber were recorded. Administration of either nedocromil sodium or placebo was ended at this time and airway response to MCh was assessed two days after PAF. The two concentration-response curves to MCh obtained before PAF exposure were superimposable. The PAF caused a dose-related bronchoconstriction in both groups; the maximal fall in V30p was 27.6 +/- 6.6 percent (mean +/- SE) in the nedocromil sodium group and 37.4 +/- 4.6 percent in the placebo group. Two days after PAF, the PC20FEV1 did not change in subjects who received nedocromil sodium (4.86 vs 4.32 mg/ml; geometric mean), but it fell from 6.59 to 1.12 mg/ml (p less than 0.05) in placebo-treated subjects. These results indicate that nedocromil sodium inhibits PAF-induced increase in airway reactivity.

Protective effects of inhaled ipratropium bromide on bronchoconstriction induced by adenosine and methacholine in asthma

Although adenosine-induced bronchoconstriction is mainly due to mast cell mediator release, vagal reflexes have also been implicated in this response. We have investigated the effect of a specific muscarinic-receptor antagonist, ipratropium bromide, on methacholine- and adenosine-induced bronchoconstriction in a randomized, placebo-controlled, double-blind study of 12 asthmatic subjects. Airway response was evaluated as forced expiratory volume in one second (FEV1). Inhaled ipratropium bromide (40 micrograms), administered 20 min prior to bronchoprovocation, increased the provocation dose of inhaled methacholine and adenosine required to reduce FEV1 by 20% from baseline (PD20) from 0.11 to 0.79 mg (p less than 0.01) and from 0.57 to 1.27 mg (p less than 0.01), respectively. The mean baseline FEV1 values after administration of ipratropium bromide were significantly higher than after placebo administration (p less than 0.05). However, there was no correlation between the degree of bronchodilatation and dose-ratios for methacholine and adenosine. The findings of the present study implicate vagal reflexes in the bronchospastic response induced by inhaled adenosine in asthma.

Protective effects of inhaled ipratropium bromide on bronchoconstriction induced by adenosine and methacholine in asthma

Although adenosine-induced bronchoconstriction is mainly due to mast cell mediator release, vagal reflexes have also been implicated in this response. We have investigated the effect of a specific muscarinic-receptor antagonist, ipratropium bromide, on methacholine- and adenosine-induced bronchoconstriction in a randomized, placebo-controlled, double-blind study of 12 asthmatic subjects. Airway response was evaluated as forced expiratory volume in one second (FEV1). Inhaled ipratropium bromide (40 micrograms), administered 20 min prior to bronchoprovocation, increased the provocation dose of inhaled methacholine and adenosine required to reduce FEV1 by 20% from baseline (PD20) from 0.11 to 0.79 mg (p less than 0.01) and from 0.57 to 1.27 mg (p less than 0.01), respectively. The mean baseline FEV1 values after administration of ipratropium bromide were significantly higher than after placebo administration (p less than 0.05). However, there was no correlation between the degree of bronchodilatation and dose-ratios for methacholine and adenosine. The findings of the present study implicate vagal reflexes in the bronchospastic response induced by inhaled adenosine in asthma.

Partial regression of vascular structural alterations in hypertensive patients treated with alpha-beta-blocker, labetalol

We studied the structural and functional characteristics of the vascular bed at calf level in 46 middle aged hypertensive patients (20 males and 26 females) treated with different beta-blockers. After one week of placebo, the patients were divided into three groups: group 1 was treated with labetalol, an alpha-beta-blocker (200 mg t.t.d.); group 2 was treated with acebutolol, a cardioselective beta-blocker with intrinsic sympathomimetic activity (ISA) (200 mg t.t.d.); group 2 was treated with acebutolol, a cardioselective beta-blocker with intrinsic sympathomimetic activity (ISA) (200 mg t.t.d.); group 3 was treated with metoprolol, a cardioselective beta-blocker without ISA (100 mg t.t.d.). Before and after placebo, and after three months of active drug treatment, we measured blood pressure, and rest and peak flow at the calf level by strain gauge plethysmography. Basal and minimal vascular resistances were calculated as the ratio between mean blood pressure and rest or peak flow, respectively. A significant decrease in blood pressure was observed in each group. However, basal and minimal vascular resistances decreased only in the labetalol-treated group. These observations indicate that antihypertensive agents that have similar effects on blood pressure, may have different effects on minimal vascular resistance. Therefore, maximum vasodilation of arterioles improves, suggesting that long term treatment with labetalol, but not with other beta-blockers is able to induce a partial regression of vascular structural alterations in hypertensive patients.

Protection of nedocromil sodium on bronchoconstriction induced by inhaled neurokinin A (NKA) in asthmatic patients

Neurokinin A (NKA) has been shown to exert a potent contractile action on bronchial smooth muscles both in vitro and in vivo. Although this effect seems to be due either to a direct action of this peptide on specific muscular receptors or to an indirect effect on mast cells and/or nerves, its mechanism of action in bronchial asthma is still unknown. In the present study we have investigated the airway response to inhaled NKA in 10 asthmatic subjects and the activity of the novel pyranoquinoline dicarboxylic acid drug, nedocromil sodium, on this response. Ten asthmatic patients with stable asthma took part in the study consisting of four separate visits. On the first two occasions we derived histamine and NKA PD15 values in absence of any drug treatment. On the following two visits the inhalation challenge with NKA was performed after administration of either nedocromil sodium or matched placebo administered as pressurized aerosols via metered dose inhalers in a randomized double-blind order. Inhaled NKA produced a dose-related fall in FEV1 in all the subjects studied. Inhaled nedocromil sodium had a significant effect on the FEV1 response to NKA inhalation, the geometric mean PD15 value increasing from 16.6 to 32.2 x 10(-9) mol. We conclude that nedocromil sodium attenuates subsequent responsiveness to inhaled NKA in asthmatic subjects.

Aerosolized endothelin-1, but not its C-terminal hexapeptide, causes airway narrowing in the rat

We investigated the effects of aerosolized endothelin-1 (ET-1) and of its C-terminal hexapeptide, ET-(16-21), on the pulmonary mechanics of anaesthetized spontaneously-breathing rats. ET-1 inhalation caused a concentration-dependent increase in pulmonary resistance (RL) and decrease in dynamic lung compliance (Cdyn). In control conditions RL and Cdyn were 0.17 +/- 0.04 cmH2O.ml-1.s (mean +/- SE; n = 6) and 6.25 +/- 0.66 ml.cmH2O.1. respectively. After ET-1 4 x 10(-5) M RL and Cdyn averaged 1.45 +/- 0.28 cmH2O.ml-1.s (p less than 0.05) and 1.12 +/- 0.36 ml.cmH2O-1 (p less than 0.05), respectively. The pulmonary responses to ET-1 lasted up to 60 min. By contrast, ET-(16-21) inhaled up to a concentration of 10(-3) M did not affect pulmonary mechanics. These results indicate that the bronchoconstrictor activity of aerosolized endothelin-1 in the rat is not dependent on its C-terminal sequence, and suggests a role for endothelin-1 in the regulation of airway calibre.

Aerosolized endothelin-1, but not its C-terminal hexapeptide, causes airway narrowing in the rat

We investigated the effects of aerosolized endothelin-1 (ET-1) and of its C-terminal hexapeptide, ET-(16-21), on the pulmonary mechanics of anaesthetized spontaneously-breathing rats. ET-1 inhalation caused a concentration-dependent increase in pulmonary resistance (RL) and decrease in dynamic lung compliance (Cdyn). In control conditions RL and Cdyn were 0.17 +/- 0.04 cmH2O.ml-1.s (mean +/- SE; n = 6) and 6.25 +/- 0.66 ml.cmH2O.1. respectively. After ET-1 4 x 10(-5) M RL and Cdyn averaged 1.45 +/- 0.28 cmH2O.ml-1.s (p less than 0.05) and 1.12 +/- 0.36 ml.cmH2O-1 (p less than 0.05), respectively. The pulmonary responses to ET-1 lasted up to 60 min. By contrast, ET-(16-21) inhaled up to a concentration of 10(-3) M did not affect pulmonary mechanics. These results indicate that the bronchoconstrictor activity of aerosolized endothelin-1 in the rat is not dependent on its C-terminal sequence, and suggests a role for endothelin-1 in the regulation of airway calibre.

Endogenous opioids modulate the increase in ventilatory output and dyspnea during severe acute bronchoconstriction

The aim of this study was to evaluate whether endogenous opioids are involved in the regulation of breathing pattern and respiratory drive during bronchoconstriction induced by methacholine (MCh). We studied six male asymptomatic asthmatics 18 to 35 yr of age. In a preliminary study we determined the concentration of MCh causing a 60% fall in FEV1 (PC60 FEV1). On two subsequent days, we measured breathing pattern, dyspnea sensation (Borg scale), mouth occlusion pressure (P0.1), and FEV1 before and 10 min after an intravenous injection of either naloxone (0.1 mg/kg) or saline according to a randomized double-blind crossover design. A MCh concentration equal to the PC60 FEV1 was then inhaled, and measurements were repeated 5 min later. Neither placebo nor naloxone affected baseline breathing pattern, P0.1, and FEV1. Naloxone pretreatment did not influence airway response to MCh; the mean percent fall in FEV1 was 65.9 +/- 1.3 and 64.7 +/- 1.2% (mean +/- 1 SE) on the placebo day and the naloxone day, respectively. After MCh inhalation no significant changes in VE, VT, and breathing frequency occurred when patients received placebo. However, P0.1 increased from 1.48 +/- 0.17 to 3.43 +/- 0.70 cm H2O (p less than 0.05), and VT/TI fell from 0.66 +/- 0.08 to 0.52 +/- 0.04 L/s (p less than 0.05). Naloxone pretreatment resulted in an increase in breathing frequency (from 18.2 +/- 1.7 to 22.8 +/- 2.6 breaths/min; p less than 0.05) and VT/TI (from 0.58 +/- 0.06 to 0.74 +/- 0.05 L/s; p less than 0.05) after MCh.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of antihistamine (astemizole) and anticholinergic drugs (ipratropium bromide) on bronchoconstriction induced by substance P

Several studies have demonstrated that neuropeptides are present in bronchial tissue. The aim of this study was to evaluate in vivo the influence of antihistamine in comparison to an anticholinergic drug on bronchospasm induced by inhalation of substance P (SP). Seven moderate asthmatic patients (mean age = 34.4 +/- 8.9), five being female, were studied. The acetate salt of SP was prepared in 0.9% saline to produce a dose range of 23 to 184 x 10(-6) mol. Patients were studied on three separate days with an interval of 3 weeks between challenges. On the first day the dose of SP producing a 20% change in FEV1 was calculated from the individual semilogarithmic dose-response curve. On subsequent days, in a randomized double-blind manner, the patients were treated either with astemizole (20 mg BID for three days) and placebo ipratropium bromide or with placebo of astemizole (twice a day for three days) and with pressurized aerosol of ipratropium bromide (IB) (40 micrograms 20 minutes before the challenge). Two way analysis of variance was used for statistical analysis. Our results demonstrated that inhaled SP is able to produce a dose-response curve of bronchoconstriction with a geometric mean of PD20 of 50.51 x 10(-6) moles (37.38 to 68.19 x 10(-6) mol). Treatment with astemizole induced a geometric mean PD20 of 65.51 x 10(-6) mol (33.02 to 130.21 x 10(-6) mol) and the premedication with the IB induced a significant (P less than .05) shift of dose-response curve to SP (geometric mean PD20 = 109.1 x 10(-6) mol; 58.67 to 204.05 x 10(-6) mol). Our results demonstrated that bronchoconstriction induced by SP could be attributed to a weak cholinergic activation and not to histamine release.

Tachyphylaxis to repeated challenges with inhaled adenosine in asthmatic subjects

Adenosine, when administered as an aerosol to asthmatic subjects, provokes a prompt dose-dependent bronchoconstriction. The aim of this study was to establish whether tachyphylaxis in response to repeated inhalations with adenosine occurs in asthmatic subjects. Eight asthmatic patients were studied on three separate days (days A, B, and C) at the same time of day for each subject. Three inhalation tests were performed, separated by one hour, on each study day. The study was conducted in a double-blind fashion and performed in random order. On day A, three adenosine inhalation tests were performed to assess adenosine tachyphylaxis. On day B, a saline inhalation test was carried out between two adenosine challenges to assess the time course of the adenosine tachyphylaxis. On day C, three methacholine inhalation tests were performed to confirm that tachyphylaxis does not occur to methacholine. Repeated inhalation with adenosine, but not methacholine, produced a progressive loss of responsiveness to the nucleoside, which was particularly manifest with the third challenge.

[Residual hyperinsulinism after glucose oral load in obese subjects with normal glucose tolerance]

Forty-five NGT obese subjects were submitted to OGTT with IRI and CPR determinations and to euglycemic hyperinsulinemic clamp, and divided into two groups: A) those with return of insulinemia toward basal values, and B) those with residual hyperinsulinism, in order to evaluate possible differences in insulin secretion and/or insulin action among them. Our data show the younger age of those with residual hyperinsulinism, that also seems related to insulin secretion, represented by IRI and CPR basal values, but not to insulin resistance parameters.

[Cefotetan in the therapy of respiratory infections. Multicenter research]

In a controlled multicenter trial 291 patients have been treated with cefotetan. They suffered from acute or chronic exacerbated bronchopulmonary disorders. In 110 patients it was possible to identify the etiological agent: enterobacteria (62), non-fermentative gram-negative bacilli (10), Haemophilus influenzae (8), Branhamella catarrhalis (1), Streptococcus pneumoniae (19), Staphylococcus aureus (12), Streptococcus pyogenes (4). In the exacerbations of chronic bronchitis (203), cefotetan was generally administered at the dose of 1 g/12 h i.m., whereas it was administered at the dose of 2 g/12 h i.v. in acute infection. The mean duration of therapy was 8.8 days. Positive clinical results were obtained in 251 patients (86.2%) with eradication of the pathogen initially isolated in 90.5% of cases. Cefotetan showed good local and general tolerance. The results obtained confirm those of studies concerning limited numbers of patients and show the efficacy of cefotetan both in acute and chronic pathologies, also in patients with serious involvement of their general conditions (concomitant pathologies, high mean age).

Epidemiology of acute diarrhea in children living in Sicily

A longitudinal survey (February 1984 - January 1985) on the incidence of acute diarrhea episodes in a sample of 8,164 children (aged 0-12 years) living in southeastern Sicily was carried out by means of weekly telephone interviews with doctors practising in the territory. The incidence rate was 0.479 (0.472-0.485 95% C.I.) per child per year and the frequency of episodes was significantly higher (p less than 0.001) in children aged 0-4 years (0.86). Diarrhea was more frequent in industrial areas than in rural ones, and almost half (45.1%) of the total episodes had a mild course. No death from diarrhea occurred and admission to hospital was reported for 8.4% of all cases.

[Role of adenosine in the pathogenesis of bronchial asthma]

Adenosine has been found to contract human bronchial smooth muscle in vitro and to induce bronchoconstriction in asthmatic patients when administered by inhalation. The importance of adenosine for bronchial tone and bronchial reactivity is still unclear. Adenosine seems unlikely to cause bronchoconstriction by a non-specific irritant effect. Some evidence suggests that the action of adenosine relates to a specific pharmacologic activity. Bronchoconstriction induced by adenosine is antagonized by theophylline and is potentiated by dipyridamole. Therapeutic concentrations of theophylline exhibit specificity for adenosine's bronchoconstrictor activity supporting the concept that the bronchospastic effect of adenosine is mediated through stimulation of cell surface receptors. Stimulation of afferent receptors producing vagally mediated reflex seems unlikely. A further explanation of adenosine bronchoconstriction is a release of mediators through potentiation of ongoing mediator release from bronchial luminal mast-cells.

Non-adrenergic non-cholinergic nervous control of airways

Traditionally, the tone of bronchial smooth muscle is mediated through the balance of two autonomic nervous systems. The existence of a third non-adrenergic non-cholinergic (NANC) nervous system in the lung has been demonstrated in animals. In contrast to high density parasympathetic innervation of smooth muscle, no evidence of adrenergic nerves was found in human airways. Electrical field stimulation of tracheal strips in guinea-pig produced an initial contraction followed by a relaxation. The contraction was blocked by atropine but the relaxation was not inhibited by a beta-adrenergic blocking agent. Immunohistochemical studies have shown that vasoactive intestinal peptide (VIP)-like immunoreactive nerves are present in the central nervous system and in the peripheral neuronal system of mammals including the human respiratory tract. Autoradiographic and immunocytochemical studies have demonstrated a high density of VIP receptors in airway epithelium, submucosal glands, pulmonary vessels and smooth muscle, especially in large airways. Functional studies in humans have confirmed the regulating role of VIP principally in the large airway.

The site of airway responses to methacholine or antigen inhalation challenge

We evaluated changes in upper airway and lower pulmonary resistance after methacholine or ovalbumin challenge in inbred rats. Methacholine or antigen were inhaled through the intact upper airway and through a tracheostomy, in two groups of normal sensitized animals. Methacholine challenge resulted in both upper airway and lower pulmonary resistance increase regardless of the inhalation route. Lower airway ovalbumin challenge caused an increase in lower pulmonary resistance with no change in upper airway resistance. By contrast ovalbumin inhalation through the nose provoked a striking increase in upper airway resistance. Atropine pretreatment of lower airways reduced lower pulmonary response to antigen. We conclude that: 1) the increase in upper airway resistance following methacholine challenge occurs through a reflex mechanism; 2) upper airway constriction following antigen challenge through the nose results from a local mechanism; 3) the site of airway constriction depends on local mechanisms and vagal reflexes.

Effect of indomethacin on adenosine-induced bronchoconstriction

The exact mechanism of adenosine-induced bronchoconstriction in patients with asthma is unknown. Adenosine contraction of guinea pig trachea was antagonized by inhibitors of cyclooxygenase. The aim of this study was to investigate the effect of indomethacin (100 mg/day) on adenosine-induced bronchoconstriction in 14 asymptomatic patients with asthma. Airway response was evaluated as FEV1, and adenosine was administered as an aerosol diluted in 0.9% saline to produce a concentration range of 0.125 to 4 mg/ml. The dose of adenosine producing a 20% change in FEV1 (PD20) was calculated from the individual semilogarithmic dose-response curve; the results of PD20 were converted to log values for statistical analysis (Student's paired t test). The study was performed on 3 separate days. On the first day, the adenosine challenge was performed, and on subsequent days patients were pretreated with either placebo or indomethacin in a randomized, double-blind manner. Inhaled adenosine caused bronchoconstriction with a geometric mean PD20 of 0.71 mg (95% confidence limits, 0.44 to 1.16). After placebo, a geometric mean PD20 of 0.91 mg (95% confidence limits, 0.53 to 1.58) was obtained. Indomethacin pretreatment decreased adenosine hyperresponsiveness and shifted the dose-response curves of adenosine challenge to the right with a geometric mean PD20 of 1.28 mg (95% confidence limits, 0.64 to 2.56). The effect of indomethacin on adenosine bronchoconstriction (p less than 0.01 versus baseline; p less than 0.05 versus placebo) suggests an indirect mechanism of adenosine on inducing release of arachidonic acid derivatives. Inflammatory mediators inhibited by indomethacin may be involved in adenosine bronchoconstriction, even if this mechanism is not relevant.(ABSTRACT TRUNCATED AT 250 WORDS)

[Inhibition of pancreatic beta-cell secretion during "glucose clamp" in patients with polycystic ovary syndrome]

Insulin-resistance is a well-known feature of polycystic ovary syndrome (PCOS) and the present paper investigates the comparative roles of the peripheral tissues and the pancreatic beta-cells in its pathogenesis. The study was conducted on 5 young women with PCOS, all of normal weight and glucose tolerance in whom the glucose-insulin clamp test had revealed reduced peripheral glucose uptake that was not influenced by other conditions typically associated with insulin-resistance. Beta-cell function was investigated in these patients and 5 healthy controls via the assessment of the efficiency of the insulin/insulin feedback which involved studying the suppression of plasma C peptide during the glucose clamp. The results suggested that the insulin/insulin beta-cell feedback mechanism had retained its efficiency despite proven peripheral insulin-resistance. These data do not therefore support the hypothesis advanced by others that there is some sort of beta-cell insulin resistance parallel to the insulin resistance of the peripheral tissues. On the basis of those results it is rather believed that in PCOS the insulin-resistance is generated peripherally while the insulin/insulin feedback in the beta-cell is unimpaired. This obliges us to rethink the role of the hyperinsulinism encountered in PCOS and suggests that the changed sensitivity of the peripheral tissues to insulin activity may constitute a primary event in the genesis of insulin-resistance. This type of behavior has been demonstrated in the obese and in people with acanthosis nigricans, all with normal glucose tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)

[Inhibition of pancreatic beta-cell secretion during a "glucose-clamp" in subjects with acanthosis nigricans]

It has long been known that acanthosis nigricans is accompanied by insulin resistance. In certain insulin-resistant states, including obesity, a more sluggish response to the insulin/insulin inhibition feedback normally present in pancreatic beta cells has been documented. Some have claimed a sort of beta-cell insulin resistance "parallel" to that of the peripheral tissues. The present study assesses the efficiency of the insulin/insulin feedback in acanthosis nigricans patients, measuring the inhibition of the production of C-peptide (the indicator of beta cell secretion) induced by the administration of exogenous insulin during glucose clamping. This was done in order to compare the roles of the peripheral tissues and the beta cells in producing the insulin resistance typical of acanthosis nigricans. The study using the glucose-insulin clamp technique was conducted on 4 Acanthosis Nigricans patients with normal glucose tolerance and 4 healthy controls, the drop in C-peptide levels after the administration of exogenous insulin being assessed in the course of both steady states. The results showed that the acanthosis nigricans patients retained a beta cell response to the exogenous insulin through their peripheral tissues presented a reduced sensitivity to insulin as revealed by the glucose-insulin clamp. It therefore seems reasonable to attribute the endocrine metabolic alteration found in Acanthosis Nigricans to a peripheral receptor and/or post receptor alteration rather than central alterations in the beta cells that have yet to be demonstrated. It is concluded that in acanthosis nigricans the peripheral insulin resistance is primarily independent phenomenon and not "parallel" to insulin/insulin feedback.

Lung permeability in smokers after ambroxol treatment

There is evidence suggesting the involvement of the surfactant system in the development of lung diseases in cigarette smokers. The aim of the present study was to evaluate the effect of Ambroxol on lung epithelial permeability (LEP) in healthy smokers. Ambroxol is known to stimulate surfactant production. Twenty male patients aged between 20 and 60 years participated in the study. They all smoked at least 15 cigarettes daily for 10 years. We carried out a random double-blind study versus placebo: the drug (Ambroxol 75 mg) or the placebo were given once a day after breakfast for 30 days. Lung permeability was evaluated through scanning pulmonary scintigraphy by inhalation of the polydispersed liquid aerosol diethylenetriaminepentaacetic acid (DTPA), labelled with 99Tc, and delivered by a 'Venticis' system. LEP was expressed as the half-time clearance from the lung of 99Tc-DTPA (T50). The significance of the differences between the two treatments was determined by the Student's test for unpaired data. LEP was not different from the baseline value (T50 = 18.49 min) after placebo administration (T50 = 19.57 min). The patients receiving Ambroxol showed an increased LEP mean value (T50 = 18.36 min) in comparison with the baseline mean value (T50 = 16.41 min). Our results demonstrate that the treatment with Ambroxol was able to decrease LEP in 6 subjects, though not significantly.

Effect of an aerosol delivery system on bronchodilator activity

Metered dose inhalers (MDIs) are often used incorrectly by patients who find difficulty using MDI for drug inhalation. The study was performed in 11 asthmatic patients in four days in order to evaluate the efficiency of a new Drug Delivery System (DDS-InspirEase) for metered dose inhalers. Clenbuterol was administered via DDS and via conventional MDI in a randomized manner. On the first two days, DDS and MDI were used by patients without any physician's help. On the subsequent days, clenbuterol was administered via DDS and via conventional MDI directly by the physician. FEV1 and MEF75 values were measured 15', 30', one hour, and two hours post-drug inhalation. Statistical analysis (ANOVA) showed that clenbuterol delivered by DDS, administered by patients or by physician, produced a greater increase in FEV1 values (P less than .05) and MEF75 values (P less than .01) in comparison to the conventional MDI on each test day. No significant differences existed between physician or patient administration of clenbuterol with DDS and MDI. The results showed a greater bronchodilator effect obtained by clenbuterol delivered by DDS.

Comparative study of the effects of nedocromil sodium (4 mg) and sodium cromoglycate (10 mg) on adenosine-induced bronchoconstriction in asthmatic subjects

The effect of nedocromil sodium (4 mg; 7.8 X 10(-6) M) on adenosine-induced bronchoconstriction was compared with that of a higher dose of sodium cromoglycate (10 mg; 24.1 X 10(-6) M). Eleven allergic asthmatic patients (mean age 26.28 +/- 12.21 years) were studied. Adenosine (0.03-4.00 mg) was administered as nebulized aerosol. The dose of adenosine producing a 20% change in FEV1(PD20) was calculated from the individual semi-logarithmic dose-response curves. Patients were studied on 4 separate days. On the first day the adenosine challenge was performed; on subsequent days patients were pretreated (20 min before challenge) with either placebo or test drug (nedocromil sodium 2 x 2 mg or sodium cromoglycate 2 x 5 mg) administered by pressurized aerosol in a randomized, double-blind manner. Statistical analysis was performed by two-way analysis of variance. Neither sodium cromoglycate nor nedocromil sodium showed a significant bronchodilator effect. In patients treated with placebo, inhalation of adenosine produced a dose-related bronchoconstriction with a geometric mean PD20 of 0.42 mg. After drug administration the mean PD20 values were 1.29 mg with sodium cromoglycate and 2.30 mg with nedocromil sodium. Both drugs produced a significant increase in mean PD20 value in comparison with placebo and baseline (P less than 0.01). These results demonstrate that nedocromil sodium (4 mg) is significantly more potent than a larger dose of sodium cromoglycate (10 mg) in inhibiting adenosine-induced bronchoconstriction (P less than 0.05).

Effect of nedocromil on bronchospasm induced by inhalation of substance P in asthmatic subjects

Several studies have demonstrated that neuropeptides are present in peptidergic fibres of bronchial tissue. The aim of the present study was to evaluate in vivo the effect of nedocromil sodium (2 x 2 mg) on bronchospasm induced by inhalation of substance P. Six moderate asthmatic patients, mean age 25.17 years, were studied. Airway response was measured as FEV1 and the dose of substance P (using a dose range of 23-736 nmol) producing a 20% decrease in FEV1 (PD20) was calculated from the individual semilogarithmic dose-response curves. Patients were studied on 3 separate days in a randomized, double-blind manner. On the first day a baseline PD20 value was determined. On subsequent days substance P challenge was performed after pretreatment (20 min before challenge) with either placebo or nedocromil sodium. Student's paired t-test and Wilcoxon's test were used for statistical analysis. The results of this study demonstrated that inhalation of substance P causes a dose-dependent bronchoconstriction and that the bronchoconstriction induced by substance P can be prevented by pre-treatment with nedocromil sodium.

On the pollen morphology and frequency of allergic sensitization in Sicily of the genus Salsola L. (Chenopodiaceae)

The pollen morphology of the genus Salsola L. (Chenopodiaceae) and the distribution of the plant in Italy was described and the frequency of sensitization in a population of allergic patients was studied. Sensitization to Salsola was present in 13.7% of 343 allergic patients. This sensitization has always been observed in association with other pollens except for one case. The importance of this sensitization in the Mediterranean areas was emphasized considering the common frequency of Chenopodiaceae sensitization and the very frequent cross-reactivity within the same family and between Chenopodiaceae and Amaranthaceae.

Enhancing effect of dipyridamole inhalation on adenosine-induced bronchospasm in asthmatic patients

The study was performed on 13 asthmatic patients to determine whether inhaled dipyridamole would act directly by inducing bronchoconstriction or indirectly by potentiating the adenosine-induced bronchoconstriction. The study was performed in 3 consecutive days. On the first day adenosine challenge was performed and the PD20 value calculated. On the other days the adenosine challenge was done 5 min after randomized inhalations of dipyridamole or a control solution. The mean percent change in FEV1 after dipyridamole (delta % = 2.0) and control solution (delta % = 1.0) was not significant. Inhaled adenosine caused bronchoconstriction with a geometric mean PD20 of 1.09 mg. After control solution inhalation, a mean PD20 value of 1.31 mg was observed. Dipyridamole inhalation increased adenosine hyperresponsiveness and in all subjects shifted the dose-response curves of adenosine challenge to the left with a mean PD20 value of 0.40 mg. This enhancing effect of dipyridamole was significant when compared with the baseline value (P less than 0.01) and control solution (P less than 0.01). The study demonstrated that dipyridamole inhalation increased airway responsiveness to adenosine in all subjects. This effect is due to indirect activity of dipyridamole on airways without changes in baseline airway caliber.

Interference of oral poliovirus vaccine on RIT 4237 oral rotavirus vaccine

A vaccination trial, performed on 86 3-month-old infants, has shown that the ability of the RIT 4237 live attenuated rotavirus strain to induce seroconversion is dramatically reduced when administered with live poliovirus vaccine. In a subsequent trial performed on 93 infants the attempt to overcome the poliovirus interference by administering two doses of associated vaccines was unsuccessful. No interference by the RIT 4237 strain on live attenuated polioviruses was observed.

Bronchospasm induced by inhalation of substance P: effect of sodium cromoglycate

The aim of this study was to evaluate in vivo the effect of inhaled substance P (SP) and to determine the effect of sodium cromoglycate (SCG) on bronchospasm induced by its inhalation in 6 asthmatic patients. At the beginning of the study, all patients were asymptomatic, with an FEV1 value not less than 20%. SP was administered as aerosol, prepared in 0.9% saline to produce a dose range of 0.03-1 mg. Airway response was measured as FEV1 using a pulmonary system 47120A Hewlett-Packard instrument. The dose of SP producing a 20% change in FEV1 was calculated from the individual semi-logarithmic dose-response curve (PD20). After administration of the placebo, SP produced a dose-related bronchoconstriction with a geometric mean PD20 of 0.15 mg. After SCG, the mean PD20 value was of 0.64 mg (p less than 0.01). These results confirmed the bronchospasm induced by inhalation of SP and demonstrated that SCG is able to prevent this effect although it is impossible to define the exact mechanism of the drug.

Effect of sodium cromoglycate and nifedipine on adenosine-induced bronchoconstriction

Inhaled adenosine causes bronchoconstriction in asthmatic patients. In 7 symptom-free asthmatics a study was performed to investigate the effect of sodium cromoglycate and nifedipine on adenosine-induced bronchoconstriction. All patients were challenged with increasing doses (from 0.03 to 2 mg) of nebulized adenosine to assess airway reactivity. The same procedure was repeated on different days at the same time each morning after administration of placebo and drugs in a randomized double-blind study. Airway response was measured as the forced expiratory volume in 1 s (FEV1). The PD20 value and the fall of FEV1 at the provocative dose were calculated. The PD20 data were modified in log values and the statistical analysis was performed by two-way analysis of variance. Mean decrease of FEV1 after adenosine challenge was 26.02 and 28.87% with placebo sodium cromoglycate and placebo nifedipine, respectively. Sodium cromoglycate and nifedipine gave a mean decrease of FEV1 of 6.44% (p less than 0.05) and 22.22%, respectively. PD20 values (geometric mean) after adenosine inhalation were 0.72 and 0.74 mg for placebo sodium cromoglycate and placebo nifedipine and 0.86 mg for nifedipine. Sodium cromoglycate gave a significant protection against adenosine in all subjects and in no case did the maximum dose used (2 mg) result in a fall in FEV1 value greater than 20%. Adenosine antagonism could be considered as a possible factor contributing to the pharmacologic efficacy of sodium cromoglycate in asthmatic patients. No protective effect was noticed with nifedipine.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship between in vivo airway reactivity and in vitro responsiveness of tracheal smooth muscle in inbred rats

We evaluated the in vivo and in vitro airway responses to cholinergic stimulation in two highly inbred strains of rats. Five Fisher and six Lewis rats inhaled aerosols of doubling concentrations of methacholine (MCh). Pulmonary resistance (RL) was measured before and after each MCh inhalation. The concentration of MCh required to double RL (EC200RL MCh) was calculated. Spirally cut tracheal strips were suspended in an organ bath and the isometric tension was recorded. Cumulative concentration-response curves to carbachol were obtained using concentrations ranging from 10(-9) to 10(-3) M in half-log increments. The maximum tension (Tmax) developed and the negative log of the molar concentration required to induce 50% of Tmax (pD2) were calculated. The geometric mean of ED200RL MCh for the Fisher group was significantly lower than that for the Lewis group (0.68 and 2.66 mg/ml, respectively; p less than 0.05). No significant difference was found for Tmax (0.67 +/- 0.11 vs. 0.50 +/- 0.11 g) and pD2 value (6.24 +/- 0.08 vs. 6.21 +/- 0.22 -log M), indicating a similar contraction of tracheal smooth muscle. We therefore conclude that (1) in vivo airway responsiveness is strain-related and genetically determined in the rat; (2) that there is no correlation between in vivo and in vitro airway response to cholinergic stimulation and (3) that intrinsic properties of airway smooth muscle do not account for the differences observed in airway responsiveness in vivo.

Bronchodilator effect of Aerochamber and Inspirease in comparison with metered dose inhaler

This trial was performed in a randomized double-blind manner on four different days in 13 asthmatic patients in order to compare the bronchodilator efficacy of two different inhalation devices, Inspirease (IP) and Aerochamber (AC), to the conventional metered dose inhaler (MDI). The results showed that clenbuterol determined a significant FEV1 increase inhaled either via MDI or via IP and AC. IP caused a greater bronchodilatation than AC, 30 min after clenbuterol administration. IP caused a greater mean increase (P less than 0.05) in FEV1 than the MDI at all time intervals; AC provided an improvement in bronchodilator response over directly administered MDI. Such responses are only marginally clinically relevant when patients use MDI correctly. These devices are mainly indicated in patients with poor hand-lung coordination.

Relationship of serum theophylline concentrations to histamine-induced bronchospasm

This study was performed in a randomized double-blind manner on 6 separate days in 10 asthmatic patients to investigate the effect of a sustained theophylline on baseline bronchial hyperreactivity to histamine in relation to the theophylline serum levels and the degree of bronchodilatation produced. No significant bronchodilatation was seen after theophylline administration at every time of evaluation. An improvement of PD20 values of histamine was observed after 4 h (p less than 0.05), 8 h (p less than 0.01) and 12 h (p less than 0.05) from theophylline administration versus respective PD20 values obtained with placebo at the same times. No significant correlation was found between serum theophylline levels and percentage change of PD20 values after drug administration (r = 0.250). We observed an improvement of PD20 mean values in relation to the maximal serum theophylline concentration but our study failed to correlate the degree of protection with serum concentration.

Effect of nifedipine on allergen-induced bronchoconstriction

The effect of nifedipine on allergen-induced asthma in nine asthmatic subjects was studied. All subjects had a history of asthma and positive Prick test; lyophilized allergen extracts of Dermatophagoides Pteronyssinus were used. All solutions were inhaled through DeVilbiss nebulizer. On the first day baseline FEV1 value was measured, allergen extracts were inhaled at increasing doses. The procedure was repeated until a 20% fall from the baseline FEV1 was obtained. Nifedipine or placebo capsules were administered sublingually in a randomized double blind manner. Antigen challenge was given 30 minutes later by using provocating dose of allergen. The change in FEV1 value was calculated from the post nifedipine administration. A significant negative correlation (p less than 0.01) was found between the percentage of protection and the baseline PD20. Nifedipine produced a significant mean change of the bronchial reactivity threshold (p less than 0.01).

Effect of Duovent (ipratropium bromide and fenoterol) on non-specific bronchial hyperreactivity

Beta 2-adrenergic and anticholinergic drugs have shown an action in modulating bronchial hyperreactivity to various stimuli (chemical, physical, immunological, pharmacological). The aim of our study was to compare the efficacy of a combination of ipratropium bromide and fenoterol (Duovent) with the activity of single drugs in the prevention of histamine-induced bronchospasm. Twenty-six atopic asthmatic subjects were examined in a double-blind trial, during an asymptomatic period, with a FEV1 value not lower than 20% of the predicted normal value. During 4 consecutive days all patients received 2 puffs, respectively, of Duovent (200 micrograms fenoterol + 40 micrograms ipratropium bromide), fenoterol (400 micrograms), ipratropium bromide (80 micrograms) and placebo in a randomized order. PD20 values were evaluated after each drug administration: after 2 h in 16 patients and after 5 h in the other 10 patients. The data were modified to log values, and statistical analysis was performed by two-way analysis of variance. This study showed that Duovent and fenoterol have a protective effect against histamine-induced bronchospasm with a significant increase in the PD20 values 2 h (p less than 0.01) and 5 h (p less than 0.05) after treatment when compared to placebo. Duovent inhalation determined a more protective effect than other drugs but not significantly when compared to fenoterol. Some advantages in the modulation of bronchial reactivity could be seen from using Duovent because with the lower dose of the beta 2-adrenergic drug the same results could be obtained without side-effects.

Effect of a calcium antagonist, nifedipine, in exercise-induced asthma

The nifedipine effect was studied in 8 extrinsic asthmatic subjects with exercise-induced asthma. Before the exercise the patients received, in a randomized double-blind manner, either 20 mg nifedipine, sublingually or sodium cromoglycate by inhalation on 2 separate days. Nifedipine and sodium cromoglycate in all patients inhibited the exercise fall in FEV1. No differences were found between the two drugs. Nifedipine is a potent antagonist of calcium ion influx in smooth muscle and secretory cells, and these studies suggest that it may inhibit release of mast cell mediators and reduce bronchial smooth muscle contractility in asthma.

Effect of CDP-choline on the biosynthesis of nucleic acids and proteins in brain regions during hypoxia

The effect of CDP-choline on the in vivo incorporation of labeled precursors into DNA, RNA, and proteins in cerebral hemispheres, cerebellum, and brainstem of guinea pigs after hypoxic treatment was studied. The labeling of macromolecules extracted from the various subcellular fractions of these brain regions was also determined. Hypoxic treatment affected macromolecular labeling to a different extent in the three brain regions examined. CDP-choline treatment was not able to reverse the effect of hypoxia on DNA labeling, but it was able to remove the effect of hypoxia on RNA and protein labeling. The action of CDP-choline was particularly evident on the labeling of RNA in nuclei and mitochondria of the cerebellum and on the labeling of proteins in microsomes of the three brain regions examined.

Effect of CDP-choline on the biosynthesis of phospholipids in brain regions during hypoxic treatment

Acute administration of CDP-choline (i.p. 100 mg/Kg b.w.), 10 min before the intraventricular injection of labeled precursors, [2-3H] glycerol and [1-14C]-palmitate, was able to correct the impairment caused by hypoxic treatment of lipid metabolism in some brain regions, ie, cerebral hemispheres, cerebellum, and brainstem. After CDP-choline treatment, an increase of the specific radioactivity of total lipids and of phospholipids was observed in mitochondria purified from the three above-mentioned brain regions of the hypoxic animals, while no effect on the other subcellular fractions was found. CDP-Choline had a stimulating effect particularly on the incorporation of both precursors into mitochondrial PC, PE, and polyglycerophosphatides isolated form the three brain regions examined. The results obtained show that the action of CDP-choline in restoring lipid metabolism was more pronounced in brain mitochondria, which, among subcellular fractions, were the most affected by the hypoxic treatment.

In vivo incorporation of 3H-glycerol and 14C-palmitate into lipids of subcellular fractions of the myocardium hypertrophied during experimental hypoxia

Incorporation of labelled precursors into neutral lipids and phospholipids of hypertrophied guinea-pig cardiac ventricles during normobaric hypoxia (breathing gas mixture of N2: O2, 9: 91%) was studied. The lipids of the heart were isotopically labelled in vivo with [1-14C] palmitate and [2-3H] glycerol, and, after a period of 2 hours, the incorporation of the two injected precursors into mitochondrial and microsomal fractions was determined. Eighty hours after the onset of the hypoxic treatment, the specific activities of isolated lipids showed a more elevated incorporation into lipid classes of hypoxic right and left ventricles with respect to that of the control. For both precursors, the percent increase of incorporation into microsomal and mitochondrial neutral lipids was higher than into phospholipids. In the microsomal fraction the increase of 14C-radioactivity incorporation was more pronounced than 3H-incorporation. 3H/14C incorporation ratio appeared decreased in hypoxic ventricles. The data in this experiment suggest that the net increase of 3H-glycerol and 14C-palmitate incorporation into myocardial lipid classes was a compensatory response of the heart to the hypoxic stimulus.