Evolving role of theophylline for treatment of chronic childhood asthma.
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Adrenergic beta-Agonists↗
Biomedical subjects
R F Lemanske
Publications and source records attributed to R F Lemanske.
Adverse reaction to lupine-fortified pasta.
A 5-year-old girl with peanut sensitivity experienced urticaria and angioedema after ingesting a spaghetti-like pasta fortified with sweet lupine seed flour. The pasta was extracted and used in immunologic studies in patients with peanut sensitivity to determine whether such individuals are at similar risk. Results of skin prick tests with the lupine pasta extract were positive in five of seven subjects; these patients also reported a history of adverse reactions to green peas. In direct RAST studies IgE binding from pooled sera from patients with peanut sensitivity to the lupine pasta extract was 7 times that of a nonallergic control serum, and individual serum samples demonstrated binding from 1 to 6 times that of the negative control. Direct RAST studies of lupine seed flour with serum samples from patients with peanut allergy demonstrated IgE binding 1 to 11 times that of the negative control. Immunoblotting studies of electrophoretically separated pasta extract and lupine seed flour proteins showed IgE-binding protein bands at approximately 21 kd and in the range of 35 to 55 kd molecular weight. We conclude that some peanut-sensitive patients may be at risk for adverse reactions to lupine.
Adult↗
Reversal of persistent postbronchiolitis airway abnormalities with dexamethasone in rats.
Viral bronchiolitis is a common disease that may result in persistent airway abnormalities. Previous studies of neonatal bronchiolitis in rats revealed chronic sequelae, including airway obstruction, airway hyperresponsiveness, increased production of airway eicosanoids, and increased numbers of bronchiolar mast cells. To address the hypothesis that postbronchiolitis airway obstruction is caused in part by reversible processes, we tested whether obstruction could be reversed by a brief course of high-dose corticosteroids. Neonatal Brown Norway rats (5 days of age) were inoculated with parainfluenza type 1 virus or sterile vehicle. At 8 wk of age, rats were treated with dexamethasone (1.4 mg.kg-1 x day-1 sc) or saline for 3 days and were evaluated for lung mechanics, gas exchange, and lung inflammatory cells 1 day after the last injection. Dexamethasone normalized the chronic virus-induced airway obstruction and reduced the numbers of bronchiolar mast cells and other inflammatory cells. Resistance and dynamic compliance correlated significantly with bronchiolar mast cells but not with other airway inflammatory cell infiltrates. We conclude that the airway abnormalities that persist in rats after recovery from neonatal bronchiolitis are associated with increased numbers of bronchiolar mast cells and are largely due to corticosteroid-sensitive mechanisms.
Airway Resistance↗
Effects of airway parasympathetic tone on responses to intravenous bronchoconstrictor agonists in rats.
To test the hypothesis that parasympathetic airway tone may affect airway responsiveness, we measured bronchoconstrictor responses to intravenous bethanechol (BCh) in anesthetized vagotomized rats with and without background vagal nerve stimulation and developed a predictive model based on pharmacological additivity between endogenous and intravenous agonists. A high degree of agreement (r2 = 0.93) between the measured and predicted responses indicated that intravenous BCh and parasympathetic tone had bronchoconstrictor effects that were pharmacologically additive. An expansion of the additive model was used to determine that the percentage of decrease in respiratory system conductance (Grs) would be a measure of airway response independent of background parasympathetic tone. As predicted, the percentage of decrease in Grs after intravenous BCh was minimally affected by background vagal stimulation. However, the percentage of decrease in Grs was augmented by vagal stimulation for intravenous 5-hydroxytryptamine hydrochloride, a known parasympathetic neuromodulator, and for methacholine, an agonist with nicotinic as well as muscarinic activity (P < 0.02 for each agonist). We conclude that airway parasympathetic tone can be a source of variability for airway responsiveness when substances having neuromodulatory activity are involved in the provocative challenge.
Animals↗
Virus-induced airway obstruction and parasympathetic hyperresponsiveness in adult rats.
Viral respiratory infections in humans have been associated with exacerbations of late allergic responses and asthma, as well as with airway abnormalities that persist after resolution of the acute infection. We hypothesized that augmented parasympathetic contractile mechanisms may contribute to postviral airway dysfunction. We studied airway physiology in anesthetized rats at 1 to 8 wk after inoculation with Parainfluenza 1 virus or vehicle. The virus groups had airway obstruction (abnormal lung mechanics, gas exchange and residual volume), and increased sensitivity to intravenous methacholine at 1 to 4 wk, although methacholine hypersensitivity was minimal in vagotomized rats; these abnormalities were absent at 7 to 8 wk after inoculation. Airway responses to vagal parasympathetic nerve stimulation were enhanced markedly at 1 to 4 wk, and significantly at 7 to 8 wk, after viral inoculation. Dysfunction of M2 muscarinic autoreceptors during acute viral infection was indicated by a significant attenuation of gallamine-induced augmentation of airway parasympathetic responses; in contrast, gallamine-augmentation of parasympathetic responses at 2 to 8 wk after viral inoculation was not different from noninfected control animals. We conclude that respiratory virus infection in rats produces airway dysfunction that remains for weeks after resolution of the acute infection, and that is caused in part by parasympathetic hyperresponsiveness, associated both with M2 autoreceptor malfunction and with M2-independent mechanism(s).
Animals↗
Asthma and exercise.
There is evidence that the overall prevalence of asthma is increasing in the general population. Asthma is the leading cause of chronic illness and the most common chronic respiratory disorder in children. Given sufficient exercise intensity, exercise can trigger acute exacerbations in virtually all individuals with asthma. Heat loss, water loss, postexertional airway rewarming, and the role of several mediators have been proposed as possible mechanisms responsible for the airway obstruction induced by exercise. Exercise-induced asthma can be easily diagnosed and treated in the majority of patients. Physical training should be part of the asthmatic patient's overall plan of management. When properly treated, asthmatic individuals should be able to participate or compete in the majority of sports.
Algorithms↗
Association of mononuclear cells and eosinophils with airway resistance and responsiveness in rat pulmonary inflammatory responses.
To evaluate the association of various leukocytes with pulmonary resistance and methacholine responsiveness, we induced pulmonary eosinophil-rich inflammation in IgE-sensitized (ovalbumin) Sprague Dawley rats. Sensitized rats were challenged with either relevant (OA) or irrelevant antigen by tracheal insufflation a) with no other treatment, b) in conjunction with intravenous Sephadex beads pretreatment, or c) with antigen coupled covalently to Sepharose beads. About 24 h after antigen challenge, respiratory system resistance (Rrs), response to aerosolized methacholine, and pulmonary histopathology were evaluated. Challenge with OA, insufflation with Sepharose, and treatment with i.v. Sephadex all independently increased inflammatory cell infiltrates, but the combination of OA with the other agents did not significantly enhance the inflammatory response over OA alone. Interactive stepwise regression techniques were utilized to identify correlates for Rrs and methacholine responsiveness. Mononuclear cell score was a significant predictor (p < .01) for Rrs, and insufflation of Sepharose had a significant independent effect on Rrs (p = .01) above that predicted by mononuclear cell infiltrates. Conversely, eosinophil score and neutrophil score were not significant predictors for Rrs, and challenges with antigen or Sephadex had no significant independent effect on Rrs beyond that predicted from mononuclear cell infiltrates. Eosinophil score was the only significant histological predictor for methacholine responsiveness (p < .0001). Challenges with Sephadex, antigen and Sepharose did not significantly change methacholine responsiveness independently of the changes associated with eosinophil infiltrates. These findings suggest that mononuclear cells and eosinophils contribute to increases in airway resistance and responsiveness, respectively, following the induction of pulmonary inflammation by both allergic and non-allergic stimuli.
Airway Resistance↗
The impact of respiratory infections on asthma.
It is apparent that the effects of viral respiratory infections on the development of airway hyperresponsiveness are multiple and interrelated and involved the production of viral specific IgE, upregulation of leukocyte inflammatory activity, enhancement of the factors involved in the generation of late phase allergic responses, altered beta-adrenergic and cholinergic nervous system activity, and damage to the airway epithelium. The summation of these effects is the development of airway inflammation rather than a direct effect on bronchial smooth muscle, per se. An understanding of this pathogenesis underscores the relative importance of anti-inflammatory rather than antimicrobial therapy in viral-induced exacerbations in asthma symptoms.
Adolescent↗
Anesthetic effects on pulmonary allergic responses in rats: changes in sensitivity to serotonin.
Subsequent to observations that pulmonary responses to antigen challenge are of different magnitudes in sensitized rats that are anesthetized with different drugs, we conducted studies to test whether the alterations in responses were due to changes in airway responsiveness to cholinergic or serotonergic challenge, opioid-receptor mediated events, or changes in mast cell mediator release. Immunoglobulin E-sensitized rats anesthetized with ketamine/urethan had larger changes in lung resistance and plasma histamine after pulmonary antigen challenge compared with rats anesthetized with fentanyl-droperidol. Blockade of opioid receptors with naloxone did not affect the responses. In unsensitized rats, airway responses to aerosolized methacholine were similar for the two anesthetics, indicating unchanged smooth muscle responsiveness; however, airway responses to intravenous serotonin were enhanced by ketamine and ablated by droperidol. We conclude that ketamine- and droperidol-induced alterations of pulmonary allergic responses are due to changes in sensitivity to serotonin and in mast cell mediator release. We speculate that mast cell mediator release may be modulated by a serotonin receptor-linked mechanism.
Airway Resistance↗
Mechanisms of airway inflammation.
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Airway Obstruction↗
The relationship of viral respiratory infections and asthma.
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Antibodies, Viral↗
Persistent airway hyperresponsiveness after neonatal viral bronchiolitis in rats.
Viral bronchiolitis in human infants has been associated with permanent changes in small airways and gas exchange and an increased incidence of hyperresponsive airways later in life. Respiratory infection by Sendai virus in neonatal rats also has been reported to cause permanent changes in lung morphology and increased numbers of bronchiolar mast cells and eosinophils. We evaluated pulmonary mechanics, gas exchange, and airway responsiveness in rats at 7 and 13-16 wk after neonatal Sendai virus infection. Rats from the virus group had lower arterial PO2 and increased total lung resistance compared with controls. There were no significant differences between groups for arterial PCO2, dynamic lung compliance, quasi-static respiratory system compliance, or vital capacity. Rats from the infected group were significantly more sensitive to aerosolized methacholine than were controls, although both virus and control groups became less sensitive with age. We conclude that neonatal Sendai virus infection in rats results in persistent alterations in lung function and airway responsiveness. This phenomenon may be valuable for the study of the relationships among airway inflammation, lung morphology, and airway hyperresponsiveness, and it may be relevant to human airway disease.
Airway Resistance↗
Experimental rhinovirus 16 infection potentiates histamine release after antigen bronchoprovocation in allergic subjects.
Viral respiratory infections exacerbate asthma in many patients. We hypothesized that one mechanism by which this effect occurs may include potentiated or altered mediator release by mast cells and/or basophils to favor the development of late-phase asthmatic reaction (LAR). Therefore, we studied eight subjects with allergic rhinitis before and during an experimentally induced rhinovirus 16 (RV16) infection. We determined levels of plasma histamine and tryptase, and we observed the associated patterns of airway obstruction that developed following inhaled antigen challenge. Bronchial responsiveness to histamine, methacholine, and antigen were all significantly increased during the RV16 illness. Further, the incidence of LAR was significantly higher (five of eight) during the infection than before (one of eight; p = 0.014). In addition, in those patients whose pattern of response following antigen challenge converted from an immediate response only before infection to a dual response (immediate + late phase) during infection, plasma histamine concentrations after challenge were significantly greater than in those whose pattern of response did not change. We conclude that one mechanism by which RV16 infection increases the likelihood of LAR could include enhanced mediator release from pulmonary mast cells or from circulating or recruited basophils.
Adult↗
Oral sulfite sensitivity and provocative challenge in a 2 year old.
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Administration, Oral↗
Pathogenesis of asthma.
Asthma is the most common chronic lower respiratory tract condition in children. Thus, it is imperative that physicians caring for asthmatic patients understand the pathophysiology of asthma and its implications for optimal therapeutic management. A precise understanding of asthma pathophysiology has been impeded due to the fact that a universally acceptable definition for asthma has been difficult to formulate. Clinicians treating asthmatic patients should be aware that the airway obstruction present in these individuals is the result of multiple interrelated factors. Although bronchial smooth muscle spasm can be effectively treated producing rapid symptomatic relief, other factors contributing to airway obstruction, such as airway inflammation and edema, need to be a major focus of therapeutic strategies for more chronic management. While the concepts of reversibility and hyperresponsiveness have been appreciated for some time, the idea that asthma should be viewed as an inflammatory lung disease (or syndrome) has only recently received appropriate emphasis. In this regard, the late phase asthmatic response has provided a convenient model to study the biochemical and cellular interactions that contribute to the pathogenesis of asthma. Further, these responses will aid in the analysis of the potential beneficial effects of various pharmaceuticals as they undergo development and testing for use in asthmatic patients.
Airway Obstruction↗
The late phase response: clinical implications.
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Arthus Reaction↗
Once daily fluticasone propionate aqueous nasal spray is an effective treatment for seasonal allergic rhinitis.
A multicenter double-blind, randomized, parallel group study was conducted to evaluate the once daily administration of fluticasone propionate, a potent, new corticosteroid preparation, for the treatment of seasonal allergic rhinitis. Adult patients (n = 227) were treated for 2 weeks with fluticasone propionate aqueous nasal spray 200 micrograms QD or 100 micrograms BID or matching placebo during the autumn pollen season. Overall, the administration of fluticasone propionate once daily in the morning was as effective as the twice daily dosage regimen, and either regimen was more effective than placebo. Improvement in clinician-rated and patient-rated nasal symptom scores, including morning nasal obstruction, was evident within three days of fluticasone propionate therapy and continued throughout the treatment period. Fewer patients receiving fluticasone propionate used rescue medication and had nasal eosinophilia compared with patients receiving placebo. Adverse events were similar in frequency and nature in all three treatment groups. Morning plasma cortisol concentrations and response to cosyntropin stimulation were similar across groups and offered no evidence of HPA axis suppression. We conclude that fluticasone propionate aqueous nasal spray administered once daily is a safe and effective treatment for seasonal allergic rhinitis. The convenience of a once daily regimen may encourage better compliance.
Administration, Intranasal↗
A dose-ranging study of fluticasone propionate aqueous nasal spray for seasonal allergic rhinitis assessed by symptoms, rhinomanometry, and nasal cytology.
Fluticasone propionate is a new glucocorticosteroid with potent topical activity. In a double-blind, randomized, parallel-group study, 423 adult patients with moderate to severe seasonal allergic rhinitis received placebo or fluticasone propionate aqueous nasal spray at doses of 25, 100, or 400 micrograms twice daily (b.i.d.) for 2 weeks. Efficacy was evaluated by nasal symptom scores, nasal airflow, nasal cytology, and global evaluation. All doses of fluticasone propionate were significantly better than placebo in reducing symptoms of seasonal allergic rhinitis. Patients receiving the largest dose of fluticasone propionate (400 micrograms b.i.d.) had a slightly greater reduction (not significant) in symptom scores than patients receiving the smallest dose (25 micrograms b.i.d.). Symptom improvement was evident within 3 days of treatment. Nasal airflow improved in the groups treated with fluticasone propionate, 100 and 400 micrograms b.i.d. Examination of nasal cytograms revealed a striking decrease in both eosinophils and basophils in all three groups receiving active treatment compared with placebo. There were few adverse events and no treatment-related abnormalities in laboratory assays or evaluations of hypothalamo-pituitary-adrenocortical axis function. Comparison of treatment groups indicated that fluticasone propionate aqueous nasal spray was as safe as placebo at the doses studied.
Administration, Intranasal↗