Biomedical subjects

G M Corbo

Publications and source records attributed to G M Corbo.

59 records · Page 4Linked to original sources

PubMed1986

Comparison of bronchial responses to ultrasonically nebulized distilled water, exercise, and methacholine in asthma.

We compared the responses to inhaled methacholine, ultrasonically nebulized distilled water, and exercise in 25 subjects with atopic asthma. The methacholine inhalation test and challenges with distilled water and exercise were performed on three separate days 48 hours apart. Bronchial responsiveness to methacholine and ultrasonically nebulized distilled water was measured as the concentration of methacholine (PC20M) and the volume output of the ultrasonic nebulizer (PO20 UNDW) producing a 20 percent fall in the forced expiratory volume in one second (FEV1). The response to exercise was expressed as the percentage of fall in FEV1 from the value before exercise. Seventeen subjects showed a fall in FEV1 of more than 20 percent after exercise. Eight subjects had a stimulus-response curve to distilled water that was flat up to the maximal volume output from the nebulizer, but only four of them also showed no significant response to exercise. The response to exercise correlated better with PO20 UNDW (r = -0.66; p less than 0.01) than with PC20M (r = -0.19; p greater than 0.5) in those responding to distilled water. In all of the tested subjects, exercise-induced bronchoconstriction correlated with PC20M (r = -0.61; p less than 0.01). The mean PC20M was significantly lower in the subjects with a significant response to distilled water and exercise (p less than 0.001 and p less than 0.0001, respectively). We concluded that ultrasonically nebulized distilled water and exercise provoke significant bronchoconstriction in the subjects with more severe nonspecific bronchial hyperresponsiveness. The correlation found between the two stimuli supports the hypothesis that they act by similar mechanisms.

Adolescent↗

PubMed1986

Protective effect of disodium cromoglycate on allergen-induced bronchoconstriction and increased hyperresponsiveness: a double-blind placebo-controlled study.

The protective effect of 40 mg cromolyn on allergen-induced late response and increased hyperresponsiveness were studied in five asthmatic children to whom this drug and saline placebo were administered 20 minutes before allergen inhalation, at random, double-blind. Cromolyn reduced the magnitude of early and late responses and abolished the increase in methacholine responsiveness.

Adolescent↗

PubMedDate not supplied

Questionnaire data as predictors of urinary cotinine levels among nonsmoking adolescents.

The strength of association between urinary cotinine and questionnaire data on passive smoking among 542 adolescents was evaluated. There were 103 individuals with urinary cotinine higher than 30 ng/ml; they were compared with all other subjects. The single variable that best predicted the urinary cotinine level was maternal smoking. A strong effect was made by house size and, consequently, house crowding. Maternal smoking and house crowding had a synergic effect. The subject's perception of passive smoking at home also was an independent indication of a high cotinine level. The final model had a fairly good sensitivity, whereas the specificity was somewhat lower. The results suggest that maternal smoking, house crowding, and subject's perception of a smoky environment could be surrogate indices of high passive smoking exposure in this age group and could be useful for epidemiologic studies.

Adolescent↗

PubMedDate not supplied

Bronchial responsiveness in children living in areas with different air pollution levels.

This study evaluated the prevalence of increased bronchial responsiveness (BR) in children living in two areas with different air pollution levels. A total of 1,215 methacholine challenge tests were performed among a random sample of primary schoolchildren in an industrial town polluted by oil-fired thermoelectric power plants and in a rural area chosen as a control. The two groups showed similar lung function data (forced vital capacity [FVC] and forced expiratory volume in 1 s [FEV1.0]) and prevalence of positive prick tests to common aeroallergens. All children responding with a 20% drop in FEV1.0 to a methacholine concentration < or = 64 mg/ml, "all responders" (PC20FEV1.0 < or = 64 mg/ml), and the subgroup of "strong responders" (PC20FEV1.0 < or = 4 mg/ml) were compared separately with "nonresponders" (PC20FEV1.0 > 64 mg/ml), calculating odds ratios (ORs). There were more "all responders" (57.2% versus 41.4%) and "strong responders" (20.0% versus 14.8%) among subjects living in the industrial area; the excess remained when several potential confounders were taken into account ("all responders": OR = 2.0, 95% confidence interval [95% CI] = 1.5-2.6; "strong responders": OR = 1.9, 95% CI = 1.3-2.8), and it was even more pronounced among girls. When the effect of clinical predictors of increased airways responsiveness (history of asthma, allergic rhinitis, baseline airways caliber, skin reactivity, recent respiratory infection) was considered through multiple logistic regression, the odds ratios associated with living in the industrial area were still significantly increased in girls. The cross-sectional approach and the lack of individual exposure data limit the interpretation of the findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMedDate not supplied

[Increase of nonspecific bronchial reactivity after occupational exposure to vanadium].

A study was conducted to evaluate the level of bronchial responsiveness among workers recently exposed to vanadium pentoxide during periodical removal of ashes and clinker from the boilers of an oil-fired power station. A total of 11 male workers were examined 40-60 hours after the last exposure; male subjects, comparable as to age and smoking habits and not exposed to vanadium, were randomly chosen among the employees of the same power station as a control group. None of the subjects in the two groups had symptoms of bronchial inflammation or significant airways obstruction. However, bronchial responsiveness, investigated using a methacholine challenge test, was significantly higher in the exposed group. It is suggested that exposure to vanadium increases bronchial responsiveness even without clinical appearance of bronchial symptoms. The role of such increased level of airways responsiveness as a risk factor for chronic obstructive lung disease is speculated.

Adult↗