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Allergic rhinitis is a common cause of chronic cough. Topical corticosteroids are regarded as the most effective first-time treatment in allergic rhinitis. In this study we evaluated the cough sensitivity during the early and late allergic responses in guinea pigs with experimental allergic rhinitis. Another aim of the study was to follow up the effect of inhaled beclomethasone dipropionate on the cough in guinea pigs with allergic rhinitis. 31 guinea pigs were sensitized with ovalbumin (OA). Animals were intranasally challenged with OA (experiment) or saline (control) in 7-day intervals for 9 weeks. Cough was induced by inhalation of citric acid aerosols in gradually increasing concentrations for 30 s and was evaluated 1 h after the 8th nasal challenge (NCH) and 17 h after the 9th NCH. Cough was significantly increased only during an early allergic response, 1 h after repeated NCH [18 (14-23) vs. 8 (3-10); P<0.001]. Five experimental animals were inhaling aerosol of beclomethasone dipropionate seven days between the 8th and the 9th NCH and cough was evaluated 1 h after the 9th NCH. Inhaled corticosteroids significantly inhibited the enhanced allergic rhinitis related cough [4 (1-9) vs.19 (9-37) vs. 6 (3-9); P<0.05].
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In the present study we investigated the effects of nasal histamine on the intensity of coughing and the effects of intensified nasal breathing following nasal histamine on cough sensitivity (CS) in 14 subjects with seasonal allergic rhinitis. The study consisted of two parts performed one week apart. First, baseline CS to capsaicin was determined, followed by intranasal histamine challenge (4mg/ml, 0.1 ml) and the count of the number of coughs to inhaled capsaicin on the background of most intensive nasal symptoms (sneezing, itching, rhinorrhea, and nasal blockage) evoked by histamine. In the second part, CS was determined after intranasal histamine followed by 10 min of intensified nasal breathing through the nose or mouth in a randomized order at 2-day intervals. The number of coughs induced after intranasal histamine was significantly higher, compared with intranasal saline, [9 (7-12) vs. 4.5 (4-6), P<0.001]. CS also was significantly increased after nasal histamine, but nasal intensified breathing failed to cause any changes in CS. We conclude that stimulation of nasal mucosa with histamine enhanced the cough response in subjects with allergic rhinitis.
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Antileukotriene treatment and allergic rhinitis-related cough in guinea pigs

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Experimental allergic rhinitis produces enhanced cough response in awake guinea pigs. Leukotriene receptor antagonists, as anti-inflammatory agents, have been effective in treatment of asthma and allergic rhinitis to inhibit the early and late allergic response. In the present study, we evaluated the effect of montelukast (Singulair, Merck, USA) on the cough reflex in an experimental model of allergen-induced rhinitis in guinea pigs. Guinea pigs (n=16) were sensitized with intraperitoneal ovalbumin (OVA). The animals were then used to develop a model of allergic rhinitis by repeated intranasal instillation of 0.5% OVA at weekly intervals for 8 weeks. Allergic rhinitis was evaluated from the occurrence of typical clinical symptoms including sneezing, conjuctival and nasal secretion, or nasal acoustic phenomenon. Between the 6th and 8th nasal challenge (NCh) the animals (n=8) were treated daily for 14 days with oral montelukast (10mg/kg). Cough was induced by citric acid aerosol inhalation in gradually increasing concentration (0.05-1.6 M) and was evaluated before sensitization and then after the 1st, 6th, and 8th nasal challenge when rhinitic symptoms were most conspicuous. The intensity of cough was significantly increased after the first and repeated nasal OVA challenges, and reduced after the 8th NCh that was preceded with montelukast treatment [9(6-14) vs. 16.5(14-22) vs. 25.5(23-42) vs. 8.5(8-13); P=0.0003]. We conclude that antileukotriene therapy suppresses the stimulating effect of experimental allergic rhinitis on the chemically-induced cough in awake guinea pigs.
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Cough sensitivity in allergic rhinitis

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The objective of this study was to evaluate capsaicin cough sensitivity in pollen sensitive patients with allergic rhinitis at the time of grass pollen season and out of it. Cough reflex sensitivity was defined as the lowest capsaicin concentration that evoked 2 or more coughs (C2). Capsaicin aerosol in doubled concentrations (from 0.02 to 200 µmol) was inhaled by a single breath. Two groups of pollen sensitive rhinitis subjects and a group of healthy controls were studied. The C2 for the 23 pollen sensitive patients of the first group, studied out of pollen season (January-February), was 0.22 µmol/l (0.06-0.76) (geometric mean + 95% CI), which was substantially lower than the 4.29 µmol/l (2.54-7.26) in 24 healthy volunteers (P=0.0001). In another group of 15 pollen sensitive patients, C2 was 0.84 µmol/l (0.14-5.20) out of pollen season and 0.11 µmol/l (0.03-0.33) during the pollen season (May-June) (P=0.04). We conclude that pollen-sensitive subjects who suffer of seasonal allergic rhinitis have significantly greater capsaicin cough sensitivity, regardles of them being in or out of pollen season. Subclinical inflammatory changes in the lower airways are probably responsible for this effect.
The aim of this study was to perform molecular analysis of canine adenovirus 2 (CAV-2) E1B 19K gene fragment isolated from 20 dogs of various breeds (12 males and 8 females aged 1-9 years), with clinical symptoms of upper respiratory tract infections, from the Lubelszczyzna region. Nasal swabs were taken from dogs. DNA of CAV-2 was detected using the PCR method in 16 swabs. All PCR products were sequenced, and the obtained sequences were compared with each other and with the sequence of the E1B 19K gene of the CAV-2 strain from an online database of NCBI GenBank: AC 000003. Based on analysis of the obtained sequences, three polymorphic variants of CAV-2 (No.1-3) with homology of 78 - 100% were distinguished. The nucleotide and amino acid sequences of the most frequently represented polymorphic variant, No. 1, differed from the sequences of polymorphic variant No. 2 with one substitution. The nucleotide and amino acid sequence of the E1B 19K gene of CAV-2 AC 000003 differed from the analogous sequences of representatives of variant No. 1 with 44 nucleotide and 19 amino acid substitutions. The small number of nucleotide differences in the E1B 19K CAV-2 gene among the examined own isolates, compared with AC 000003, suggest that the infections in dogs were caused by a relatively genetically stable virus which occurs in eastern Poland.
In the present study we investigated the possibility of central convergence of neural pathways coming from distant anatomical regions in modulating the cough response. We addressed this issue by inducing cough from the tracheo-bronchial region on the background of capsaicin-stimulated and mesocain-blocked nasal mucosa in 14 anesthetized guinea pigs. The control group consisted of 6 guinea pigs in which the active agents, capsaicin and mesocain, were substituted for by inert physiological saline. All animals were tracheostomized, and the larynx was disconnected from the proximal part of the trachea with preserved innervations, and all were subjected to the same protocol. Cough, induced by mechanical irritation of the tracheo-bronchial mucosa, was elicited three times: in the control condition, after intranasal capsaicin challenge, and after another capsaicin challenge preceded by intranasal instillation of a local anesthetic, mesocain. The main finding of the study was that the number of cough efforts per bout, assessed from positive deflections on the intrapleural pressure recordings, was significantly enhanced by intranasal capsaicin challenge and this effect was reversed by intranasal pretreatment with the anesthetic mesocain [2.1 ±0.2 (control) vs. 3.5 ±0.4 (capsaicin) vs. 2.2 ±0.2 (capsaicin after mesocain) (P<0.01)], with no appreciable changes in the magnitude of cough efforts. The cough response in the control group remained unchanged. We conclude that tracheo-bronchial cough may be modified by neural sensory input to the brain coming from nasal mucosa. Therefore, cough reflex is subject to central convergence of peripheral neural pathways originating at distant anatomical locations.
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Effects of thorax irradiation on citric acid-induced cough in guinea pigs

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Thoracic irradiation may cause an acute lymphocytic alveolitis or hypersensitivity pneumonitis. It is well known that cough reflex is sensitized by a number of inflammatory mediators. The purpose of the present study was to investigate the effect of the thoracic irradiation on the cough response in awake guinea pigs. Guinea pigs (Trik strain) were exposed to sham irradiation (n=16), a single irradiation dose of 10 Gy (n=12), and a fractionated irradiation dose (in five fractions) of 15 Gy (n=12) delivered to the thorax. Cough was induced by citric acid aerosol inhalation in gradually increasing concentrations (0.05-1.6 M) during the first week after thoracic irradiation. The cough response was expressed as a total number of coughs induced during all citric acid challenges. Irradiated animals with single dose of 10 Gy exhibited a time- dependent significant increase of citric acid-induced cough in the 6th day after irradiation compared with control animals (P=0.005), whereas cough was not altered significantly in irradiated animals with fractionated dose of 15 Gy. This study demonstrates that the increased cough response may be a determinant of the functional changes of airway nerve-endings mediating cough in the early phase after thoracic irradiation.
Some patients with allergic rhinitis and no clinical evidence of asthma exhibit bronchial hyperresponsiveness. In the present study, induced sputum and acetylcholine and capsaicin challenges were assessed in four groups of adult subjects: allergic rhinitis (AR), allergic rhinitis with lower airway symptoms (ARLA), mild stable asthma (BA), and healthy volunteers (C) to correlate lower airway inflammatory markers with bronchial and cough reactivity. Patients with AR (n = 13) and ARLA (n = 11) did not take any anti-inflammatory drugs. Those with BA (n = 9) used inhaled corticosteroids and C (n = 10) were respiratory symptoms free. The patients underwent capsaicin cough challenge and sputum induction with hypertonic saline during the first visit, and acetylcholine bronchial challenge on a separate day. We found that the percentage of eosinophils in induced sputum was significantly higher in patients with AR, ARLA, and BA than in C 14.5 ±1.8(SE) vs. 13.5 ±2.9 vs. 13.9 ±4.0 vs. 3.6 ±0.8 %, respectively (P=0.012). In contrast, acetylcholine PD20 in patients with AR, ARLA, and BA was significantly lower than in C 5.6 ±0.9 vs. 4.1 ±0.4 vs. 2.8 ±0.4 vs. 12.9 ±2.7 mg, respectively (P=0.0001). Neither the eosinophil percentage nor PD20, nor cough sensitivity appreciably differed across the patients groups. Sputum eosinophils correlated significantly with the acetylcholine PD20 (r=0.37, P=0.016). We conclude that eosinophilic inflammation of lower airways and increased bronchial reactivity were present in adult patients with allergic rhinitis.
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