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PubMed1990

The relationship between conductance and functional residual capacity during drug-induced bronchoconstriction.

UNLABELLED: We wondered if the inverse changes in airway conductance (Gaw) and functional residual capacity (FRC) during histamine (H) and acetylcholine (ACH) challenge are interrelated or occur at random. In 14 normal and 14 asthmatic subjects, we determined FRC and Gaw changes corresponding to changes in specific airway conductance (SGaw) around -40 percent produced by an aerosol of H or ACH inhaled quantitatively and with measured lung deposition. We also assessed the elastic recoil following H inhalation (5A). We found that in 11 normal and nine asthmatic subjects, after H or nine normal and 11 asthmatic subjects after ACH, Gaw and 1/FRC were linearly and directly related (p less than 0.05). The steepness of this slope was directly related to the resting Gaw values. A similar relation was uncovered in the literature for asthmatic patients at rest or during recovery from natural asthma. As the elastic recoil was normal and did not change after H, it could not explain delta FRC at delta SGaw of -40 percent. IN CONCLUSION: (1) during H or ACH challenge, Gaw-FRC relationship in normal or asthmatic subjects tends to be hyperbolic and dependent on resting Gaw; (2) such a relationship is seemingly present in other bronchoconstrictor responses with a different pathogenesis; and (3) during bronchoconstriction, as Gaw vs FRC is no longer linear, SGaw becomes volume dependent.

Acetylcholine↗
PubMed1999

Proventil HFA prevents exercise-induced bronchoconstriction in children.

Short-acting inhaled beta2-agonists used just prior to exercise are an effective method for preventing exercise-induced bronchoconstriction (EIB) in children. This was a randomized, single-blind, placebo-controlled, four-period crossover study that compared the effectiveness of albuterol formulated in hydrofluoroalkane-134a (HFA) to albuterol formulated in chlorofluorocarbons (CFCs) and to placebo in protecting asthmatic children age 6-11 from EIB. Patients self-administered either HFA albuterol, two different CFC albuterol products, or placebo 30 min prior to exercise challenge. Spirometry was performed predose and 5, 10, 15, 30, 45, 60, 75, and 90 min after the exercise challenge was completed. The smallest percent change from the predose forced expiratory volume in 1 sec (FEV1) after exercise challenge was similar for the three active treatments, and each of the active treatments was significantly better than placebo. Each active treatment had significantly fewer patients unprotected from EIB (unprotected defined as having >20% fall in FEV1 after exercise challenge) than placebo. Changes in heart rate, blood pressure and electrocardiogram (ECG) intervals were similar for the three active treatments following exercise. HFA albuterol is as effective as albuterol products formulated in CFCs and more effective than placebo in protecting asthmatic children from EIB.

Adrenergic beta-Agonists↗
PubMed2005

Airway hyperresponsiveness to hypertonic saline as a predictive index of exercise-induced bronchoconstriction.

BACKGROUND: Changes in airway mucosal osmolarity are an underlying mechanism of bronchoconstrictive responses to exercise and hypertonic saline (HS). The purpose of this study was to examine whether an osmotic challenge test using HS can predict exercise-induced bronchospasm (EIB) in asthma patients. METHODS: Thirty-six young male asthmatic patients underwent bronchial challenge tests based on 4.5% HS, exercise (> 24h later), and methacholine (MCh) at the Chonnam National University Hospital. The relationships between responses to HS and exercise, and between MCh and exercise were evaluated. RESULTS: The maximal fall in forced expiratory volume in one second following exercise was significantly higher in the HS-responders (n=19) than in the HS-nonresponders (n=17, 35.9 +/- 4.1% vs. 17.9 +/- 2.7%, p<0.001), and there was a significant correlation between the severity of EIB and HS-airway hyperresponsiveness (AHR). When compared with the MCh-AHR test in terms of predicting EIB, the HS-AHR test showed higher specificity (71.4% vs. 42.90%), but a lower sensitivity (58.6% vs. 89.7%) and negative predictive value (29.4% vs. 50.0%). At the moderate AHR cutoff value, the MCh-AHR test had a specificity that was comparable with and predictive values that were higher than those of the HS-AHR test. CONCLUSIONS: The HS-AHR test was more specific than the MCh-AHR test, but was less sensitive and had a poorer negative predictive value, which in combination preclude the use of the HS-AHR test as a screening tool for EIB. The MCh-AHR test had a cutoff value for moderate AHR that may be more useful for predicting EIB in asthmatic patients.

Adolescent↗
PubMed1999

[Cough, bronchoconstriction and bronchial hyperreactivity in relation to treatment with angiotensin-converting enzyme].

In the paper available information concerning the influence of treatment with angiotensin converting enzyme inhibitors (ACE-I) on cough, bronchial hyperreactivity and bronchoconstriction are reviewed. Cough occurs in 0.7% to 19% of patients treated with angiotensin converting enzyme inhibitors according to various reports. In the mechanism of angiotensin converting enzyme inhibitor-induced cough accumulation of bradykinin and substance P due to decreased degradation of this mediators caused by ACE-I may be involved. Part of tussive effect may be mediated via prostaglandins and histamine. In a few studies symptoms of airway obstruction and asthma worsening in relation to treatment with this drugs was reported. However, majority of reports suggest safety in taking ACE-I by patients with asthma. The only effective method to relieve angiotensin converting enzyme-induced cough is a drug withdrawal. The change of drugs within the whole class of ACE-I does not bring effect.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1975

Correlation of anaphylactic bronchoconstriction with circulating reaginic antibody level and active cutaneous anaphylaxis in the rat.

The interrelationships of anaphylactic bronchoconstriction, active cutaneous anaphylaxis and circulating reaginic antibody level in rats sensitized with Nippostrongylus brasiliensis have been studied. The mean rise in bronchial reactivity during the 5-week sensitization period was correlated with the rise in circulating reaginic antibody level in groups of rats, although weak bronchial reactivity was observed before circulating reagin was demonstrable. In individual animals bronchial reactivity did not significantly correlate with circulating reaginic antibody level or cutaneous reactivity. Bronchial and cutaneous reactivity on challenge may be transferred to non-sensitized rats by passive sensitization with reaginic serum. It is concluded that the ability of a tissue to respond to antigen challenge is multifactorial and may not be reliably predicted from a knowledge of circulating reaginic antibody level or the response of another tissue in the same animal.

Anaphylaxis↗
PubMed1992

Inhibitory effect of methylprednisolone suleptanate (U-67590A) on anaphylactic bronchoconstriction in guinea pigs.

Effects of U-67590A, an analogue of methylprednisolone, on antigen-induced bronchoconstriction expressed as ventilation overflow were examined in ovalbumin-sensitized guinea pigs. When administered intravenously 17-18 hr before the challenge with antigen, U-67590A at doses of 10 and 30 mg/kg caused dose-dependent inhibition of increased ventilation overflow immediately after challenge. Death due to anaphylactic shock was markedly reduced by U-67590A. At 10 mg/kg (i.v.), U-67590A given 10 min before the challenge significantly inhibited the antigen-induced increase in ventilation overflow; the greatest inhibition seen 5-6 hr prior to the challenge. Pretreatment with 10 mg/kg FPL-55712 attenuated the increase in ventilation overflow during anaphylaxic shock. It is conceivable that inhibition of the leukotriene-mediated response is involved in the glucocorticoid-induced suppression of airway obstruction in anaphylaxis, and that inhibitory action of the glucocorticoid directly acting on the airway may account for the very fast onset of action.

Anaphylaxis↗
PubMed1992

[Urinary N-methylhistamine excretion. Following exogenous histamine administration and allergy/exercise-induced bronchoconstriction].

Histamine is partly metabolized to a stabile metabolite N-methyl-histamine and excreted in the urine. We analysed the degradation of infused histamine and the N-methyl-histamine-excretion in atopic and normal individuals as in patients with a bronchoconstriction due to allergen/exercise challenge. N-methyl-histamine was determined by a newly developed radioimmunoassay. 60 controls and 38 atopic individuals were investigated. There is a proportional increase of N-methyl-histamine in the urine in young children. However, no significant difference between allergic and non-allergic individuals was found. After parenteral administration of a standardized amount of histamine 12% of the applied amount was secreted in the urine as N-methylhistamine. The most significant increase of N-methylhistamine-excretion was observed in the first hour after application. Only an 0.1% rise of N-methyl-histamine was observed following an oral administration of histamine. Neither bronchial challenge with specific allergen nor physical exercise elicited significant changes of N-methylhistamine excretion. The secretion of N-methyl-histamine demonstrates the degradation of histamine in the circulation, the measurement oft this metabolite in the urine should be considered when analysing the cause of severe systemic allergic reaction as anaphylaxis but not asthma or atopic disposition.

Adolescent↗
PubMed2004

The prevalence of exercise-induced bronchoconstriction among symptomatic sportsmen.

Exercise-induced bronchoconstriction (EIB) is a transient airflow obstruction that usually occurs 5 to 15 minutes after physical exertion. Although this condition is preventable, it is still underrecognized and affects the quality of life. The purpose of this study was to evaluate the prevalence of EIB, to find out whether self-reported symptoms were enough to establish the diagnosis of EIB and to define related symptoms and risk factors among symptomatic students of a Sports Academy in our city, which is situated at about 2,000 meters altitude and experiences a long winter period. A questionnaire was sent to students of the Sports Academy. After its evaluation, symptomatic students were invited to perform a pulmonary function test (PFT) before and after a six minute exercise test. Two hundred and seventy-seven students (205 males and 72 females, mean age: 20+/-4) from 12 different types of sport replied to the questionnaire. Of these subjects, 43% were symptomatic. Out of the 119 symptomatic students, 63 accepted our invitation. Three of them were excluded. After performing a six-minute exercise test, EIB was observed in 5 (8%) of them, whose symptoms were aggravated by cold weather. Our results suggest that EIB may be common among symptomatic sportsmen. Screening is important, since EIB could be prevented with appropriate diagnosis and treatment. Although respiratory symptoms during exercise may give important clues, only these symptoms are not sufficient to establish the diagnosis of EIB. Symptomatic patients should undergo further tests for EIB.

Adolescent↗
PubMed2005

Exercise-induced bronchoconstriction and exercise-induced respiratory symptoms in workers exposed to tea dust.

Assuming that airborne particles and pollutants are important contributing factors in the development of exercise-induced bronchoconstriction (EIB), we performed a case-control study including 63 tea workers (36 men and 27 women, aged 36-55, duration of employment 3-30 years) and an equal number of office workers, matched by sex and age. Exercise-induced respiratory symptoms were recorded in a questionnaire. Skin prick tests, spirometry, as well as exercise and histamine challenge were carried out. Environmental measurements were performed on site during the work shifts. The prevalence of self-reported exercise-induced respiratory symptoms and EIB did not differ significantly between the exposed and control group (41.6% vs 36.8%, and 6.4% vs 4.8%, respectively). In both exposed and control workers, EIB was strongly linked to asthma (P < 0.01). In the exposed workers it was significantly associated with positive family history of asthma (P < 0.01) and positive family history of atopies (P < 0.05), whereas in the exposed smokers it was significantly related to smoking duration (P < 0.05). Bronchial reaction to exercise in the exposed smokers was significantly greater than in control smokers (P < 0.05). Self-reported exercise-induced respiratory symptoms were weakly associated with EIB, with a large proportion of false positive and a low proportion of false negative results in both groups.

Adult↗
PubMed1990

Inhibition of PAF-induced histamine secretion and bronchoconstriction by WEB 2086.

Platelet activating factor (PAF) stimulates histamine secretion from rabbit mixed leukocytes in a concentration-dependent fashion (EC50 10 ng/ml). The PAF (10 ng/ml)-induced histamine secretion was inhibited by WEB 2086 (IC50 = 20 nM). Furthermore, PAF (10 ng/kg, i.v.)-induced bronchoconstriction in guinea pig was also inhibited by WEB 2086 (ID50 = 5.3 micrograms/kg, i.v., 5 minutes). These data showed the existence of PAF-receptors on rabbit basophils and in guinea pig airways which are highly sensitive to blockade by WEB 2086.

Animals↗
PubMedDate not supplied

Synergistic mechanisms in the adenosine- and neuropeptide-induced bronchoconstriction.

Neuropeptides and purines are possible neurotransmitters of the nonadrenergic noncholinergic nervous system of the airways. We investigated possible synergistic mechanisms between these two bronchoconstricting agents in a rat model. We observed that both adenosine and tachykinins enhance histamine release in the airways and that adenosine and neurokinin A act synergistically both on airway narrowing and histamine release.

Acetylcholine↗
PubMedDate not supplied

Mechanisms involved in neurokinin-induced bronchoconstriction.

Substance P and neurokinin A have been shown to be present in the sensory airway innervation. In animals and in humans, both in vitro and in vivo, neurokinin A is a more potent bronchoconstrictor than substance P, suggesting that NK-2 receptors mediate their bronchoconstrictor action. Pharmacological studies on rat airways and in asthmatic patients have shown that a large part of the bronchoconstrictor effect of neurokinins is indirect. In animals (rabbit, rat and guinea-pig) neurokinins stimulate the release of acetylcholine from postganglionic cholinergic nerve fibres. Pharmacological studies performed on rat airways suggest that mast cells are also involved. In bronchoalveolar lavage studies in rats, performed immediately following the peak bronchoconstriction caused by the neurokinins, we were able to show that both substance P and neurokinin A cause histamine release into the airways. The physiological actions of neuropeptides are normally terminated by extracellular metabolism. Inhibitors of neutral metalloendopeptidase enhance the in vitro and in vivo bronchoconstrictor effect of the neurokinins. In our rat model, thiorphan not only enhanced the bronchoconstrictor effect of i.v. administered neurokinins, but also enhanced the airway histamine release caused by these sensory neuropeptides.

Animals↗
PubMed1990

[Effect of recombinant gamma interferon on allergic skin reaction and bronchoconstriction].

Gamma-interferon (IFN-gamma) has immunosuppressive and immunostimulatory effects. Net results in clinical disease are difficult to predict. We studied possible anti-allergic effects of IFN-gamma in a double blind study in 30 patients with bronchial asthma. We performed quantitative skin prick and bronchial allergen provocation tests using each patient's main allergen prior to and after 20 injections of either recombinant IFN-gamma (100 micrograms each) or placebo, measuring skin wheal area, specific airway resistance (SRaw) and the maximal expiratory flow at 50% of vital capacity (MEF50). IFN-gamma reduced skin wheal area significantly but had no effect on allergic bronchoconstriction.

Asthma↗
PubMed1990

[Measurement of airway resistance by an interrupter technique in anesthetized dogs during methacholine induced bronchoconstriction].

Airway resistance was measured by an interrupter technique in anesthetized and paralyzed dogs. Bronchoconstriction was then induced by the inhalation of methacholine hydrochloride at a concentration of 25 or 50 mg . ml-1 for ten minutes. Airway resistance was measured again immediately after the inhalation of methacholine and 50 minutes later. Under normal conditions, airway resistance increased with a linear relationship to the expiratory airflow as expressed by a function of Y = K1 + K2X. K1 and K2 were calculated by a least square method. As a result, K1 increased markedly immediately after the inhalation of methacholine and returned to the control level thereafter. However, it was still higher than the control 50 minutes later. On the other hand, no statistically significant changes were observed because the changes in K2 were variable. In some cases, K2 increased, while in others it was unchanged. K2 decreased in more cases, however, and a negative value was often seen. This inverse correlation between flow and resistance was supposed to reflect the occurrence of small airway obstructions during the end expiratory phase. Therefore, it was considered that this method is capable of detecting small airway abnormalities which could not be detected by %FEV1.0.

Airway Resistance↗
PubMed1990

Comparative effects of volume history on bronchoconstriction induced by hyperventilation and methacholine in asthmatic subjects.

The aim of this study was to find out if bronchodilatation following deep inspiration can be induced by the inhalation of a "natural" stimulus (hyperventilation of cold dry air), and if the effect is similar to that induced by methacholine. After baseline assessment of lung resistance (RL), 10 asthmatic subjects were asked to inhale cold dry air for 3 min. RL was monitored continuously for 3-4 min, at which time subjects were asked to take a fast deep inspiration. After recovery, the manoeuvre was repeated and RL was reassessed. The manoeuvre was then repeated a third time. After functional recovery, progressive doses of methacholine were inhaled until the increase in RL was comparable to that obtained after hyperventilation (56 +/- 16% and 65 +/- 24%, respectively, mean +/- SD, NS). The same deep inspiration manoeuvre was repeated three times with recovery as after hyperventilation of cold dry air. Maximum changes in RL were not significantly different after each of the three manoeuvres for either type of bronchoconstriction. The mean fall in RL was 14.2 +/- 9.9% after hyperventilation and 16.4 +/- 10.5% after methacholine. There was a satisfactory correlation (r = 0.80, p less than 0.01) between the bronchodilatation after deep inspiration for both types of stimuli. We conclude that the bronchodilator effect of deep inspiration is no different using either a pharmacological stimulus (methacholine) or a "natural" stimulus (hyperventilation of unconditioned air). These results show that assessing the response to hyperventilation with manoeuvres requiring deep inspiration, forced expiratory volume in one second (FEV1) may alter airway tone in a way similar to pharmacological stimuli.

Asthma↗
PubMed1990

Separation of cough and reflex bronchoconstriction by inhaled local anaesthetics.

Cough and airway constriction are common features of respiratory diseases. Both can be caused by stimulation of airway nerves. We have studied the effects of airway anaesthesia on these reflexes, stimulated by inhaled capsaicin, in order to determine whether they are controlled by the same sensory nerves. Ten volunteers had capsaicin cough dose responses performed before and at 10 min after inhaling placebo (ascorbic acid in saline), and the topical anaesthetics lignocaine 40 mg, and dyclonine 8 and 4 mg. The effect of the drugs on respiratory resistance (Rrs), measured using a forced oscillation technique, was measured both before and after the inhalation of a dose of capsaicin which caused less than two coughs. Lignocaine (40 mg) and dyclonine (8 mg) caused significant reports of oral anaesthesia but only lignocaine reduced the cough response to inhaled capsaicin, increasing the log dose of capsaicin causing three or more coughs by 162%. None of the treatments altered basal Rrs or its increase after inhaled capsaicin. Thus, the cough and reflex bronchoconstriction caused by inhaled capsaicin have different sensitivities to inhaled local anaesthesia, suggesting that the effect may be mediated by different sensory pathways.

Administration, Inhalation↗
PubMed1985

The role of climatic conditions and histamine release in exercise-induced bronchoconstriction.

We examined the role of climatic conditions on exercise induced asthma in patients in the tropics. Ten asthmatic patients exercised on a cycle ergometer achieving similar maximal heart rates, oxygen consumption, work load, and minute ventilation on three occasions, breathing warm humid air, cool drier air and cold dry air. Blood for plasma histamine was collected before and after exercise breathing cold air. The exercise-induced bronchoconstriction (EIB) was least in warm air, maximal in cold air and intermediate in cool air. Post exercise venous histamine was raised in only 2 out of 7 patients. We conclude that temperature and humidity have a direct role in EIB and that mediator release is probably the result rather than the cause of EIB.

Adolescent↗
PubMed1989

Mechanisms of endothelin-mediated bronchoconstriction in the guinea pig.

Intravenous injection of anesthetized ventilated guinea pigs with doses of endothelin ranging from 0.25 to 2.50 micrograms/kg caused dose-dependent decreases in respiratory system conductance and compliance. These effects were maximal 1 min after injection and had disappeared 15 min thereafter. When guinea pigs were pretreated with 3 mg/kg of propranolol or 5 mg/kg of hexamethonium, endothelin-induced bronchoconstriction rose significantly, but when they were pretreated with 3 mg/kg of propranolol plus 3 mg/kg of atropine it remained unchanged. The bronchoconstrictor effects of endothelin were suppressed in guinea pigs pretreated with 0.5 or 2 mg/kg of meclofenamate but remained unchanged in those pretreated with 30 micrograms/kg of nicardipine. Endothelin did not increase either lung permeability, as assessed by 99m technetium diethylenetriamine pentaacetic acid clearance, or airway responsiveness to histamine or 5-hydroxy-tryptamine. Histological studies showed that endothelin induced reversible contraction of airway and pulmonary artery smooth muscles but no inflammatory reactions. These results demonstrate that, in guinea pigs, endothelin 1) induces airway smooth muscle contraction mediated by cyclooxygenase metabolites and modulated by the autonomic nervous system and 2) does not induce airway hyperreactivity or inflammation.

Animals↗