BACKGROUND: Vitamin C has been reported to have a role in the decrease of airway hyperresponsiveness in animal models. This data is based on some metabolic actions of vitamin C, such as promotion of histamine degradation, producing mote PGE2 than PGE2 alpha in cyclooxygenase pathway, decrease of smooth muscle contraction, and acting as reducing agent of oxidant. It has been also known that heavy smokers have lower blood levels of vitamin C than nonsmokers and this deficiency in heavy smokers have been explained by several mechanisms, such as increased oxidation by oxidants and free radicals, increased biosynthesis of catecholamine and serotorim released by nicotine, and inadequate dietary intake. In this study, We attempted to assess effect of vitamin C on bronchial hyperresponsiveness in heavy smokers who have bronchial hyerresponsiveness and role of vitamin C on bronchial hyperresponsiveness. METHOD: To assess acute effect of vitamin C on airway hyperresponsiveness, blood sample for vitamin C level and spirometry, methacholine challenge test were done in 17 smokers and 8 nonsmokers, and one hour after oral administration of vitamin C 3 g, blood sample for vitamin C level and spirometry, metliacholine challenge test were repeated. To assess chronic effect of vitamin C on airway hyperreeponsiveness after daily administration of vitamin C 1 g for one week in 17 smokers, blood sample for vitamin C level and spirometry, methacholirie challenge test were done. To assess role of vitamin C, after oral administration of vitamin C 3 g plus indomethacin 100 mg in 12 of 15 smokers who were reactive to methacholine challenge test, spirometry and methacholine challenge test were done and after oral intake of indomethacin 100 mg in 12 smokers who were reactive to methacholine challenge test, spirometry and metbachoine challenge test were repeated. RESULT: There were no significant differences in whole blood vitamin C levels between smokers(1.17+/-0.22mg/dL) and nonsinokers(1.14+/-0.19 mg/dL) (p>0.05). Fifteen of the 17 smokers(88.2%) were reactive to metbacholine chaflenge test amd 10 of the 15 smokers who were reactive to methacholine challenge test were less than 8 mg/dL in PC20FEV1, and 7 of the 8 nonsmokers(87.5%) were nonreactive to methacltoline challenge test There were significant decrease in bronchial responsiveness after oral administration of xitamin C 3 g in 13 of the 15 smokers who were reactive to methachoine challenge test. This significant decrease persisted with maintenance daily administration of 1 g for one week. PC20FEV1 were not correlated to vitamin C levels in smokers. After oral administration of indomethacin 100 mg, significant reduction of bronchial responsiveness that occured after oral administration of xdtamin C 3 g in smokers were attenuated. CONCLUISON: Although there were no significant differences in whole blood vitamin C levels between smokers and nonsmokers, heavy smokers have significant increase in bronchial responsiveness than nonsmokers. This bronchial hyperresponsiveness of heavy smokers can be attenuated by vitamin C supplement Disappearance of vitamin C effect by indcrnethaein supplement may suggest that vitamin C exert its effect via alteration of arachidonic acid metabolism.
Administration, Oral ; Arachidonic Acid ; Ascorbic Acid* ; Dinoprostone ; Free Radicals ; Histamine ; Indomethacin ; Metabolism ; Methacholine Chloride ; Models, Animal ; Muscle, Smooth ; Nicotine ; Oxidants ; Prostaglandin-Endoperoxide Synthases ; Spirometry ; Vitamins*

BACKGROUND/AIMS: Many patients with aspirin-induced asthma have severe methacholine airway hyperresponsiveness (AHR), suggesting a relationship between aspirin and methacholine in airway response. This study was performed to determine whether methacholine AHR affects the response of asthmatics to inhaled aspirin. METHODS: The clinical records of 207 asthmatic patients who underwent inhalation challenges with both aspirin and methacholine were reviewed retrospectively. An oral aspirin challenge was performed in patients with a negative inhalation response. The bronchial reactivity index (BRindex) was calculated from the percent decrease in lung function divided by the last dose of the stimulus. RESULTS: Forty-one (20.9%) and 14 (7.1%) patients showed a positive response to aspirin following an inhalation and oral challenge, respectively. Only 24.3 and 14.3% of the responders had a history of aspirin intolerance, respectively. The methacholine BRindex was significantly higher in the inhalation responders (1.46 +/- 0.02) than in the oral responders (1.36 +/- 0.03, p < 0.01) and in non-responders (n = 141, 1.37 +/- 0.01, p < 0.001). The aspirin BRindex was significantly correlated with the methacholine BRindex (r = 0.270, p < 0.001). Three of four patients who received the oral challenge, despite a positive inhalation test, showed negative responses to the oral challenge. Two of these patients had severe AHR. CONCLUSIONS: A considerable number of asthmatic patients with no history of aspirin intolerance responded to the inhalation aspirin challenge. The airway response to aspirin was significantly correlated with methacholine-AHR, and a false-positive response to aspirin inhalation test seemed to occur primarily in patients with severe AHR.
Administration, Inhalation ; Adolescent ; Adult ; Aspirin/*administration & dosage/*adverse effects ; Asthma/*physiopathology ; Asthma, Aspirin-Induced/etiology/physiopathology ; Bronchial Hyperreactivity/physiopathology ; Bronchial Provocation Tests ; Drug Hypersensitivity/etiology/physiopathology ; Female ; Humans ; Male ; Methacholine Chloride/*administration & dosage ; Retrospective Studies ; Young Adult

Enhanced cough response has been frequently observed in chronic cough. Recently, extrathoracic airway constriction to inhaled histamine was demonstrated in some chronic cough patients. However, relation between extrathoracic airway hyperresponsiveness (EAHR) and cough sensitivity determined by capsaicin inhalation is unclear in each etiological entity of chronic cough. Seventy-seven patients, with dry cough persisting for 3 or more weeks, normal spirometry and chest radiography, and 15 controls, underwent methacholine bronchial provocation test and capsaicin cough provocation test. Elicited cough number and flow-volume curve was examined after inhalation of capsaicin to evaluate cough sensitivity and EAHR. Thirty-three patients, with postnasal drip, showed normal extrathoracic airway responsiveness, and 27 of them showed normal cough sensitivity to capsaicin. Cough sensitivity was enhanced in 14 patients with cough variant asthma (CVA) who showed bronchial hyperresponsiveness; EAHR to inhaled capsaicin was present in 12 of them. The remaining 30 patients were tentatively diagnosed as idiopathic chronic cough (ICC). Eleven ICC patients showed enhanced cough sensitivity and EAHR to inhaled capsaicin while 19 patients showed normal values. These results indicate that cough sensitivity is closely related with extrathoracic airway responsiveness during capsaicin provocation in some chronic cough patients. EAHR and enhanced cough sensitivity to inhaled capsaicin may be a part of mechanism developing chronic cough.
Administration, Inhalation ; Adult ; Bronchial Hyperreactivity/*etiology/physiopathology ; Bronchial Provocation Tests ; Capsaicin/*administration & dosage ; Case-Control Studies ; Chronic Disease ; Cough/*etiology/physiopathology ; Female ; Humans ; Male ; Methacholine Chloride/diagnostic use ; Middle Aged

BACKGROUND: A US Food and Drug Administration (FDA)-approved drug methacholine chloride (Provocholine®) was recently introduced to Korea where it is now widely used in clinical practice. We aimed to evaluate the prevalence, risk factors and cutoff value of bronchial hyperresponsiveness (BHR) to Provocholine in 7-year-old children. METHODS: Six hundred and thirty-three children from the Panel Study on Korean Children who visited 16 regional hospitals were evaluated. Skin prick tests, spirometry and bronchial provocation tests for Provocholine as well as a detailed history and physical examinations were performed. The bronchial provocation test was reliably performed on 559 of these children. RESULTS: The prevalence of ever-diagnosed asthma via medical records was 7.7%, and that of current asthma (wheezy episode in the last 12 months + diagnosed asthma by physicians) was 3.2%. The prevalence of BHR to Provocholine was 17.2% and 25.8%, respectively, for a PC20 < 8 and < 16 mg/mL. The risk factors for BHR (PC20 < 16 mg/mL) were atopic dermatitis diagnosis and current dog ownership, whereas those for current asthma were allergy rhinitis diagnosis, a history of bronchiolitis before the age of 3, recent use of analgesics/antipyretics and maternal history of asthma. The BHR prevalence trend showed an increase along with the increased immunoglobulin E (IgE) quartile. The cutoff value of PC20 for the diagnosis of current asthma in children at age 7 was 5.8 mg/mL (sensitivity: 47.1%, specificity: 87.4%). CONCLUSIONS: BHR to Provocholine (PC20 < 8 mg/mL) was observed in 17.2% of 7-year-olds children from the general population and the cutoff value of PC20 for the diagnosis of current asthma was 5.8 mg/mL in this age group. The risk factors for BHR and current asthma showed discrepancies suggesting different underlying mechanisms. Bronchial provocation testing with Provocholine will be a useful clinical tool in the future.
Animals ; Asthma ; Bronchial Hyperreactivity ; Bronchial Provocation Tests ; Bronchiolitis ; Child* ; Dermatitis, Atopic ; Diagnosis ; Dogs ; Humans ; Hypersensitivity ; Immunoglobulin E ; Immunoglobulins ; Korea ; Medical Records ; Methacholine Chloride* ; Ownership ; Physical Examination ; Prevalence* ; Rhinitis ; Risk Factors* ; ROC Curve ; Sensitivity and Specificity ; Skin ; Spirometry ; United States Food and Drug Administration