This review addresses three types of causes of respiratory system limitations to O(2) transport and exercise performance that are experienced by significant numbers of active, highly fit younger and older adults. First, flow limitation in intrathoracic airways may occur during exercise because of narrowed, hyperactive airways or secondary to excessive ...

BACKGROUND: Exercise-induced bronchoconstriction (EIB) in the asthmatic child is associated with persistent airway inflammation and poor disease control. EIB could arise partly from airway oxidative stress. Exhaled breath condensate (EBC) levels of 8-isoprostane (IsoP), which is a known marker of oxidative stress, might therefore be helpful for monitoring asthma noninvasively. ...

BACKGROUND: There is increasing evidence that exercise-induced bronchoconstriction (EIB) is associated with eosinophilic airway inflammation. In the pathogenesis of EIB the role of chemokines - responsible for promoting the migration and activation of inflammatory cells - as well as blood platelets, a potential source of those chemokines, remains unclear. METHODS: ...

The prevalence of exercise-induced bronchoconstriction is reported to be high among recreational and elite athletes, yet diagnosis is often symptom-based. Indirect challenges such as the laboratory exercise challenge provide objective criteria for proper diagnosis and treatment. However, a standardized protocol using appropriate exercise intensity, duration, and dry air inhalation is ...

1. We have reported previously that, in the smooth muscle of guinea-pig taenia caeci, the development of carbachol-induced desensitization to carbachol and histamine has a similar time-course whereas desensitization to high K(+) is interrupted by sustained resensitization. 2. In the present study, we evaluated the development of histamine-induced desensitization to ...

In order to investigate whether increased airway closure is a component of airway hyperresponsiveness (AHR), airway closure was compared during induced bronchoconstriction in 62 asthmatic, 41 nonasthmatic nonobese (control) and 20 nonasthmatic obese (obese) subjects. Airway closure and airway narrowing were measured by spirometry as percentage change in forced vital ...

We characterized the passive structural and active neuromuscular control of pharyngeal collapsibility in mice and hypothesized that pharyngeal collapsibility, which is elevated by anatomic loads, is reduced by active neuromuscular responses to airflow obstruction. To address this hypothesis, we examined the dynamic control of upper airway function in the isolated ...

BACKGROUND: Muscarinic receptor agonists increase water secretion from the acinar cells of respiratory, sweat, salivary, and lacrimal glands. Mice lacking the gene for aqueous water channel aquaporin (Aqp) 5 exhibit methacholine-induced bronchiolar hyperreactivity when compared to normal mice. Individuals with asthma also have enhanced airway responsiveness to methacholine and diminished ...

This study examined the relationship between airway blood flow (Q(aw)), ventilation (V(E)) and cardiac output (Q(tot)) during exercise in healthy humans (n=12, mean age 34+/-11 yr). Q(aw) was estimated from the uptake of the soluble gas dimethyl ether while V(E) and Q(tot) were measured using open circuit spirometry. Measurements were ...

BACKGROUND: IL-13 is a pivotal cytokine in allergic inflammation and bronchial hyperresponsiveness, and is known to influence leukotriene levels. OBJECTIVE: We investigated whether IL-13 polymorphisms may be associated with clinical phenotypes and drug responsiveness to the leukotriene receptor antagonist (LTRA) in Korean asthmatic children with exercise-induced bronchoconstriction (EIB). METHODS: We ...

A single-projection X-ray technique showed an increase in functional residual capacity (FRC) in conscious mice in response to aerosolized methacholine (MCh) with little change in airway resistance (Raw) measured using barometric plethysmography (Lai-Fook SJ, Houtz PK, Lai Y-L. J Appl Physiol 104: 521-533, 2008). The increase in FRC presumably prevented ...

BACKGROUND: Whereas increased airway hyperresponsiveness (AHR) and airway inflammation are well documented in adult elite athletes, it remains uncertain whether the same airway changes are present in adolescents involved in elite sport. OBJECTIVE: To investigate airway responsiveness and airway inflammation in adolescent elite swimmers. METHODS: We performed a cross-sectional study ...

Exercise-induced bronchoconstriction (EIB) is a consequence of evaporative water loss in conditioning the inspired air. The water loss causes cooling and dehydration of the airway surface. One acute effect of dehydration is the release of mediators, such as prostaglandins, leukotrienes, and histamine, that can stimulate smooth muscle, causing contraction and ...

C-fibers represent the majority of vagal afferents innervating the airways and lung, and can be activated by inhaled chemical irritants and certain endogenous substances. Stimulation of bronchopulmonary C-fibers with selective chemical activators by either inhalation or intravenous injection evokes irritation, burning and choking sensations in the throat, neck and upper ...

BACKGROUND: Airway hyperresponsiveness (AHR) can be studied by bronchoprovocation test (BPT) using direct (methacholine - MCh) or indirect (adenosine 5'-monophosphate - AMP) stimuli. These two substances have not been compared in cough variant asthma (CVA). OBJECTIVE: We designed a randomized, single-blind, cross-over study to compare AMP and MCh in the ...

OBJECTIVE: To compare the GlideScope video laryngoscope (GVL) with the classic Macintosh laryngoscope in simulated airway scenarios of varying difficulty. MATERIALS AND METHODS: A prospective, crossover and randomised study was performed. Four airway scenarios were simulated using the Airsim model as follows: normal; cervical spine immobilisation; tongue oedema and combined ...

BACKGROUND: A large number of patients in our country develop goiters which seem to be apparently asymptomatic. Conventional radiography does not address the abnormal air flow dynamics. Flow volume loop studies have shown characteristic dampening of both inspiratory and expiratory curves. Pulmonary function tests (PFT) can provide a simple noninvasive ...

The perimeter of the basement membrane (Pbm) of an airway viewed in cross section is used as a marker of airway size because in normal lungs it is relatively constant, despite variations in airway smooth muscle (ASM) shortening and airway collapse. In vitro studies (McParland BE, Pare PD, Johnson PR, ...

BACKGROUND AND OBJECTIVES: Increased airway responsiveness to beta-agonists is noted in asthmatics and smokers. The lung may be exposed to chemical warfare agents such as mustard gas and pulmonary complications of exposure range from no effect to severe bronchial stenosis. There is little understanding of airway hyperresponsiveness to beta-agonist drugs ...

BACKGROUND: There are no prospective studies that evaluated airway changes during labor. The purpose of this study was to evaluate airway changes in women undergoing labor and delivery. METHODS: Two studies were undertaken to evaluate airway changes during labor. The first study used the conventional Samsoon modification of the Mallampati ...

Adenosine 5'-monophosphate (AMP) bronchoprovocation reproduces the lung function abnormalities that occur spontaneously during acute asthma and detects peripheral airway inflammation better than direct bronchoconstrictive agents. Pulmonary gas exchange disturbances may reflect changes in small airways related to airway inflammation rather than bronchoconstriction alone. The present authors investigated whether AMP induced ...

The authors recently showed that preterm birth per se, in the absence of assisted ventilation or elevated inhaled oxygen levels, alters the structure of the airway walls in young lambs. The initial aim of the present study was to determine whether these changes persist into adulthood. Preterm (P; n = ...

BACKGROUND: The interactions between CD40 and its ligand, CD40L, control humoral and cell-mediated immune responses. CD40 ligation may promote asthma-associated inflammatory responses in the airways. Many reports confirm the inflammatory basis of exercise-induced bronchoconstriction (EIB) in asthmatics. METHODS: The study was conducted in a group of 19 asthmatic patients (11 ...

We present a case of anaphylactic shock induced by exercise following celery ingestion. The possible mechanism of food-dependent exercise-induced anaphylaxis (FDEIA) and the laboratory tests for its diagnosis are discussed. We evaluated spontaneous, celery-allergen-induced, and anti-FcepsilonRI-antibody-induced histamine release from basophils obtained from the patient, 2 celery-allergic controls, and 3 healthy ...

BACKGROUND: Exercise-induced bronchospasm (EIB) affects up to 90% of all patients with asthma. Objective. This study evaluated the ability of levalbuterol hydrofluoroalkane (HFA) 90 mug (two actuations of 45 microg) administered via metered dose inhaler (MDI) to protect against EIB in mild-to-moderate asthmatics. METHODS: This was a randomized, double-blind, placebo-controlled, ...

OBJECTIVES: Asthma is frequently diagnosed in military personnel despite strict guidelines that disqualify persons with active disease or a recent history of asthma. It is generally considered incompatible with military service, because of the regular physical training, outdoor training exercises, and deployments to remote locations. The objective of this study ...

For inhaled medications, bioequivalence testing is becoming increasingly important owing to the availability of many inhalation devices. We evaluated agreement between the Finney bioassay and the Emax model in the assessment of bioequivalence of salbutamol administered via a metered-dose inhaler with a spacer (pMDI+ Volumatic) or via a dry-powder inhaler ...

The airways are thought to dilate during exercise in humans but the time course and mechanisms of the response are not fully described. The aim of the study was to document changes in airway calibre during electrically induced muscular contractions (MC) in spontaneously breathing rabbits. Experiments were also performed after ...

INTRODUCTION: Asthma is frequently reported in endurance athletes, particularly in cross-country skiers. It has been reported that an exercise field test performed with the competitive type of exercise is the better for diagnosing asthma and bronchial hyperresponsiveness in athletes than bronchial provocation with methacholine. OBJECTIVE: The main objective was to ...

BACKGROUND: High-frequency chest wall oscillation (HFCWO) is commonly used by cystic fibrosis (CF) patients for airway clearance. The primary objective of this study was to determine whether the use of a newer HFCWO device that generates oscillations with a triangular waveform results in greater sputum production than a commonly used ...

We present a 14-year-old girl with self-induced areas of hypo- and hyperpigmenation on her forearm as a result of applying 10 blasts of an asthmatic aerosol inhaler directly to her skin. We emphasize the importance of being aware of potential danger associated with the common metered-dose inhaler when it is ...

In health, secretions produced in the respiratory tract are cleared by mucociliary transport, cephalad airflow bias, and cough. In disease, increased secretion viscosity and volume, dyskinesia of the cilia, and ineffective cough combine to reduce secretion clearance, leading to increased risk of infection. In obstructive lung disease these conditions are ...

RATIONALE: Aerobic conditioning improves exercise capacity and decreases symptoms in patients with asthma. However, its benefits in the context of allergic airway inflammation are poorly understood. OBJECTIVES: To evaluate the effects of two intensities of aerobic exercise on airway inflammation and remodeling in a model of chronic allergic lung inflammation. ...

RATIONALE: Congenital central hypoventilation syndrome (CCHS) is a genetic disorder mainly characterized by failure of automatic control of breathing, causing alveolar hypoventilation. Little is known regarding cough in CCHS. Parental reports indicate that patients cough normally during airway infections; however, previous studies have demonstrated no cough response to fog inhalation. ...

The relationship between exhaled nitric oxide (eNO) and bronchial hyperresponsiveness (BHR) should be clarified. The aim of this study was to determine the relationship between eNO and exercise-induced bronchospasm (EIB) by estimation of the each lung parameter in asthmatic children who performed a bicycle ergometer exercise test. Twenty children with ...

BACKGROUND: A single deep inspiration (DI) is known to be a potent bronchodilator but it is not known if repeated DI can accelerate sustained recovery from bronchoconstriction. METHODS: We induced sustained bronchoconstriction using increasing concentrations of nebulized methacholine (Mch) during tidal breathing and assessed airway narrowing by measuring respiratory resistance ...

BACKGROUND AND OBJECTIVE: It has been previously established that montelukast provides protection against exercise-induced bronchoconstriction (EIB) after a single dose. The present objective was to assess the onset and duration of this protective action in a trial that included both positive and negative controls. METHODS: A randomized, active-controlled and placebo-controlled, ...

AIM: Physical exercise requires adaptation from the airways, which includes bronchodilation. Prostaglandins are involved in airway regulation and their plasma level changes during exercise. The purpose of this study was to investigate the effect of symptom-limited exercise on the levels of prostaglandin E(2) (PGE2) and thromboxane B2 (TXB2) in the ...

OBJECTIVES: A few studies on small patient series have investigated the relationship between gastroesophageal reflux and bronchial responsiveness as expressed by exercise-induced bronchoconstriction (EIB), with non-conclusive results. The aim of this study was to evaluate whether the presence of acid in the oesophagus may influence EIB. METHODS: 45 patients with ...

The Exubera system (Pfizer, New York, NY/Nektar Therapeutics, San Carlos, CA) is an integration of five major new technologies: protein formulation, powder processing, powder filling, drug packaging, and delivery device. The product provides a simple interface, where the patient interacts only with the delivery device and powder packaging. These components ...

Heterogeneity of airway constriction and regional ventilation in asthma are commonly studied under the paradigm that each airway's response is independent from other airways. However, some paradoxical effects and contradictions in recent experimental and theoretical findings suggest that considering interactions among serial and parallel airways may be necessary. To examine ...

Exercise-induced bronchospasm (EIB) is a clinical syndrome that affects 8-20% of the general population and 11-50% of athletes. Although a variety of testing protocols for the diagnosis of EIB have been pursued, the optimal algorithm still is lacking. The aim of this study was to determine the prevalence of EIB ...

The safety of sputum induction (SI) is well described in stable asthma, but the safety of SI in exercise-induced bronchoconstriction (EIB) has not been established. Our goals were to examine the relationship between the severity of EIB and bronchoconstriction during SI, and to determine if SI conducted after exercise challenge ...

The aim of this study was to investigate the patterns and dynamics of the microbiota in the airways of ventilated patients. Seventy-four mechanically-ventilated patients were recruited consecutively, and oropharyngeal, tracheal and bronchoalveolar (BAL) fluid specimens were collected 48 h after intubation, and every 72 h thereafter until the patient was ...

BACKGROUND: Valved holding chambers improve delivery of inhaled corticosteroids to the lung but are bulky in design. A novel compact vortex actuator device has therefore been developed. OBJECTIVES: To compare the in vitro and in vivo performance of a novel compact vortex actuator (the Neohaler [NH]) vs a conventional small-volume ...

Lower airway tract colonization may trigger neutrophil-mediated airway inflammation. We investigated whether transient airway colonization influences airway inflammation and pulmonary function after lung transplantation (LTx). In this retrospective study, stable LTx patients with consecutive broncho-alveolar lavages (BAL), the first colonized and the second noncolonized, were included to create a Pooled ...

BACKGROUND: Asthma is an inflammatory disease of the airways that can lead to impaired arterial blood oxygenation during exercise. OBJECTIVE: We asked whether treatment of airway inflammation in asthmatic subjects would improve arterial blood gases during whole-body exercise. METHODS: By using a double-blind parallel-group design, 19 asthmatic subjects completed treadmill ...

The objective of this double-blind cross-over study was to evaluate montelukast for the prevention of exercise-induced bronchoconstriction (EIB). Sixty-two patients with EIB (post-exercise decrease in forced expiratory volume in 1 second (FEV(1)) > or = 20% at pre-randomization) were randomized to montelukast 10 mg or placebo, followed by exercise-challenge 2, ...

BACKGROUND: Inhaled, short-acting beta-adrenergic agonists (SAbetaAs) are widely prescribed in cystic fibrosis (CF) subjects, despite a lack of convincing data for efficacy and the potential for these agents to result in airway instability. We tested the hypothesis that inhaled albuterol would improve maximal exercise performance in CF subjects with airflow ...

BACKGROUND AND STUDY OBJECTIVE: Deep inspiration (DI) protects against methacholine-induced bronchoconstriction in healthy subjects. We hypothesized that this bronchoprotective effect of DI depends upon the inspiratory flow rate. DESIGN: Prospective, controlled study. SETTING: Pulmonary function laboratory within a large tertiary medical center. PARTICIPANTS: Ten healthy nonsmokers without asthma or rhinitis. ...