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Biomedical subjects

G M Corbo

Publications and source records attributed to G M Corbo.

At least 55 records · Page 3Linked to original sources
PubMed1989

Snoring in children: association with respiratory symptoms and passive smoking.

OBJECTIVE: To investigate the relation between snoring and various respiratory symptoms and passive parental smoking. DESIGN: Data were collected by questionnaire. SETTING: Primary schools in Guardiagrele and Francavilla in the Abruzzi region in central Italy. SUBJECTS: 1615 Children aged 6-13 years were categorised according to whether they snored often; occasionally apart from with colds; only with colds; or never. RESULTS: 118 Children were habitual snorers and 137 were reported to snore apart from when they had colds. Never snorers (n = 822) were significantly older than children in other categories. Snoring was significantly associated with rhinitis, production of cough and sputum, previous tonsillectomy, and passive parental smoking. Of the habitual snorers, 82 were exposed to passive smoking. The prevalence of habitual snoring increased significantly with the number of cigarettes smoked by parents (from 5.5% in never smoking [corrected] households to 8.8% in heavy smoking households). CONCLUSIONS: Snoring is quite common in children. The dose-effect relation of smoking and snoring shown in this study adds weight to a further adverse effect of parental smoking on children's health.

Adolescent↗
PubMed1989

Bronchial hyperresponsiveness in atopic dermatitis.

We investigated the prevalence of bronchial asthma, immediate skin reactivity and bronchial hyperresponsiveness in 40 patients with atopic dermatitis (AD). Eight patients reported to have asthma while 29 were found responders to methacholine test (PC20 Mch less than 64 mg/ml) and 21 were skin reactors. The prevalence of skin positive reactions did not differ in responder and non-responder (PC20 Mch greater than 64 mg/ml) groups. Males were more likely both to have bronchial asthma and be responders to methacholine test than females. Moreover, responders had an earlier age of onset of AD than the non-responders. We suggest that bronchial responsiveness should be evaluated in children with AD.

Adolescent↗
PubMed1989

Measurement of nasal mucociliary clearance.

The saccharin test was carried out in a randomly selected sample of schoolchildren (142 boys and 153 girls, age range 11-14 years) to determine the variability and reproducibility of the test and to assess whether it could be used as a screening test for nasal mucociliary clearance. Nasal mucociliary clearance times were analysed according to clinical history (asthma, rhinitis, asthma with rhinitis, and acute upper respiratory tract infections), laboratory findings (positive skin test responses and bronchial hyper-reactivity assessed by methacholine challenge), and parental smoking. Nasal mucociliary clearance times showed a narrow coefficient of repeatability (six minutes) in 50 subjects and there was substantial agreement between the two tests. Nasal mucociliary clearance times were less than 40 minutes in all the children. Normal children had nasal mucociliary clearance times of less than 24 minutes while significantly impaired nasal mucociliary clearance was detected in those with positive skin reactions and a positive response to methacholine challenge. We were unable to show that passive smoking had any consistent effect on nasal mucociliary clearance. We suggest that a time response between 30-60 minutes should be checked again at least two weeks later, and that children in whom repeated saccharin tests show a nasal mucociliary clearance of greater than 30 minutes should have ciliary beat frequency estimated.

Adolescent↗
PubMed1989

Controlled trial of oral fenoterol in the treatment of childhood asthma.

We evaluated the effect of oral fenoterol at a daily dosage of 0.25 mg/kg in 17 children with mild bronchial asthma following a double-blind, crossover design. Treatment with fenoterol syrup and matched placebo was given for 4 weeks each and doses administered every six hours. Daily variability of peak expiratory flow rate during fenoterol treatment was not different from that measured during placebo. Fenoterol syrup was associated with a statistically significant improvement in daytime symptom scores, whereas nighttime symptoms were not significantly reduced. Fenoterol significantly reduced the need for supplemental therapy. Adverse effects remained trivial and minimal for all children. This study indicates that fenoterol syrup alone or in combination with inhaled fenoterol may have a role in the maintenance therapy of mild to moderate childhood asthma.

Administration, Oral↗
PubMed1988

Probit analysis applied to the allergen dose-response curve: a method for epidemiologic surveys.

The degree of skin sensitivity to five common allergens (grass, Dermatophagoides pteronyssinus, mugwort, birch, and Parietaria) was determined by the threshold dilution technique in all the skin test reactors of a random sample of 295 schoolchildren (142 male and 153 female subjects, age range 11 to 14 years), and the frequency distribution of responders at each concentration was analyzed by probit analysis. The potency of each allergen was presented in terms of median effective dose (ED50), and comparison between different allergens and between symptomatic and asymptomatic subjects was made by computing the relative potency. The ED50 of the allergens was found to be nearly identical (grass, 13.5; D. pteronyssinus, 12.3; mugwort, 9.6 activity units by RAST (AUR)/ml) with the exception of birch (22 AUR/ml). Grass and D. pteronyssinus demonstrated a lower ED50 in symptomatic subjects (3.3 and 2.8 AUR/ml, respectively) than in asymptomatic subjects (85 and 27 AUR/ml, respectively). The lower fiducial limits of ED50 in symptomatic subjects demonstrated to be a cutoff point, since they included only 5% and 12% of asymptomatic reactors to grass and D. pteronyssinus, respectively. We conclude that probit analysis applied to the distribution of threshold doses of allergen extracts is a useful method to evaluate skin sensitivity in epidemiologic surveys. We believe that the ED50 is a practical and reliable allergy index.

Allergens↗
PubMed1988

Airway responsiveness to exercise and ultrasonically nebulized distilled water in children: relationship to clinical and functional characteristics.

We studied the bronchial response to exercise and ultrasonically nebulized distilled water (UNDW) challenge in 19 normal controls (3 females and 16 males; age 6-13 years) and in 44 asthmatic children (12 females and 32 males; age 6-13 years) in order (1) to determine the sensitivity and specificity of the two challenges and (2) to evaluate the relationship between bronchial responses and clinical and functional characteristics. A 20% fall in FEV1 was regarded as a significant bronchial response. The specificity of both challenges was high (100%), whereas the sensitivity of exercise (77.3%) was twice that of UNDW (38.6%). The combination of the two challenges increased the sensitivity to 81.8%. There was no correlation between the magnitude of bronchial response to exercise and UNDW (rs = -0.03; p greater than 0.05). Exercise responders were not different from nonresponders in regard to gender, age, resting lung function, length of asthmatic history and treatment requirement to control symptoms. However, the UNDW responders were different from nonresponders in regard to age (p less than 0.05) and length of asthmatic history (p less than 0.001). Children younger than 9 years old are unlikely to show a bronchial response to UNDW inhalation, since only 9.5% of them developed a significant bronchoconstriction. We suggest that the two stimuli recognize some different pathways or subjects have basic biological differences.

Adolescent↗
PubMed1988

Evaluation of bronchial responsiveness by pharmacological challenges in asthma. Inhaled propranolol in comparison with histamine and methacholine.

Bronchial challenges with bronchoconstrictive drugs have supplied important information on some relevant pathophysiological aspects of bronchial asthma, i.e. nonspecific bronchial hyperresponsiveness. Until now histamine and methacholine have been the most widely used inhalation tests. Recently, propranolol, given by inhalation, has been proposed and evaluated for possible application as a bronchial provocation challenge both in clinical and experimental setting. In asthmatic subjects with bronchial hyperresponsiveness to histamine and methacholine, inhaled propranolol induces a dose-related bronchoconstriction. In a group of 25 asthmatic patients, the mean value of provocative doses, in mumoles of propranolol that causes a 20% drop in FEV1 (PD20FEV1), is thirteen times greater than that of methacholine. In the same study, there is no correlation between the bronchial responses to the two drugs. Moreover, none of 9 normal subjects of the control group responds to inhaled propranolol. The mechanisms of propranolol-induced bronchoconstriction are poorly understood. A cholinergic reflex is probably involved, but it is likely that propranolol has some different and rather peculiar pathways. Bronchial response to inhaled propranolol is a reliable, reproducible, safe, and well-tolerated method. Bronchoconstriction induced by propranolol appears to be a very promising technique in the investigation of the mechanisms of nonspecific bronchial hyperresponsiveness.

Adolescent↗
PubMed1987

Effects of two doses of cromolyn on allergen-induced late asthmatic response and increased responsiveness.

We selected five atopic children with asthma with previously documented late asthmatic response (LAR) associated with increased hyperresponsiveness to methacholine after the inhalation of Dermatophagoides pteronyssinus. The children had four allergen inhalation tests on 4 different days, at least 14 days apart. On days 1 and 4, saline placebo was inhaled 1 hour before the expected onset of LAR, and FEV1 was measured hourly until FEV1 returned within 10% of baseline value; then methacholine challenge was performed. On days 2 and 3, 20 and 40 mg of cromolyn was inhaled double blind 1 hour before the expected onset of LAR. FEV1 and methacholine responsiveness were measured as on days 1 and 4. The two doses of cromolyn significantly delayed the LAR onset without altering the overall LAR magnitude and prevented the allergen-induced increase in methacholine responsiveness. Both these effects were greater at the maximal dose used. We conclude that cromolyn can prevent the allergen-induced increase in methacholine responsiveness and that this effect is not due to alteration in the magnitude of LAR. Our findings reveal a possible explanation of the effectiveness of this drug in the treatment of allergic asthma.

Adolescent↗
PubMed1987

The effect of indomethacin on the refractory period occurring after the inhalation of ultrasonically nebulized distilled water.

We examined the involvement of inhibitory prostaglandins in refractoriness induced by repeated ultrasonically nebulized distilled water (UNDW) challenge. Six male subjects with asthma who developed both UNDW-induced bronchoconstriction and refractoriness after UNDW were studied on 3 separate days, 1 week apart. On each study day, subjects had an initial UNDW challenge. UNDW responsiveness was assessed with dose-response curves of UNDW volume output versus the percent fall in FEV1. The output provoking a 20% fall in FEV1 (PO20 UNDW) was calculated. FEV1 was measured again at 5-minute intervals until it returned to within 5% of baseline value. UNDW challenge was then repeated. On day 1, the two successive UNDW challenges were performed in absence of any treatment (control day). Before days 2 and 3, subjects received placebo capsules or indomethacin, 100 mg per day, in a double-blind, randomized fashion for 3 days. On both the control and placebo days, repeated UNDW inhalation provoked a significant increase in PO20 UNDW (p less than 0.01), indicating refractoriness. On the indomethacin day, the mean PO20 UNDW during the second UNDW challenge was not significantly different from that obtained during the initial test on that day (p greater than 0.05), indicating that refractoriness did not occur. We suggest that inhibitory prostaglandins are involved in the development of refractoriness after UNDW inhalation.

Adolescent↗
PubMed1987

Allergy indices based on allergen dose-response curve in a randomly selected sample of schoolchildren.

Skin-test sensitivity was computed in 61 schoolchildren drawn from a stratified random sample in order to generate two allergy indices based on a quantitative skin-test assay: Individual Allergy Index (IAI) and Population Allergy Index (PAI). The former to quantitate IgE-mediated skin test sensitivity of each subject, the latter to describe the degree of skin reactivity of our sample to a single allergen. Five allergen extracts were tested at 4-fold dilutions. Sensitivity endpoint data were used to generate IAI. Frequency distribution of IAI seemed to be bimodal as asymptomatic subjects gathered at the lower part while symptomatic children showed a peak in the middle. By means of criteria based on the relation between IAI and the prevalence of symptoms we were able to classify atopy in five classes from normal (all asymptomatic subjects) to severe atopy (all symptomatic subjects). Each positive reaction was plotted as a function of the allergen concentration eliciting the weal, and linear regression with confidence limits was calculated for grass and Dermatophagoides pteronyssinus only. PAI was represented by the slope, which depends on the reactivity of the sample, and the intercept, which involves the potency of the allergen as well. Grass and D. pteronyssinus showed the same slope while the intercepts differed. The slope increased if we considered symptomatic subjects only. We propose both these indices for clinical and epidemiological studies.

Adolescent↗
PubMed1987

Effect of two doses of inhaled diltiazem on exercise-induced asthma.

Seven asthmatic children with moderately to severely increased bronchial responsiveness to methacholine took part in a double-blind placebo-controlled study to assess the effect of a calcium channel blocker, diltiazem, on exercise-induced asthma (EIA), and its duration. On the control day, bronchial response to exercise was found to be highly reproducible when performed 2 h apart (intraclass correlation coefficient 0.92). Normal saline and diltiazem at concentrations of 1.75 and 3.50 mg/ml (estimated nebulized doses 5 and 10 mg, respectively) were given in random order before exercise on a bicycle ergometer. Exercise challenge was performed 20 min and 2 h after each treatment, and bronchial response was expressed as percent fall in the forced expiratory volume in 1 s. In the overall group, diltiazem did not significantly change resting bronchial tone and produced no significant (p = 0.18) attenuation of EIA. An almost complete protection was detected only in two subjects 20 min after diltiazem 10 mg. This limited effect waned 2 h after the administration.

Administration, Inhalation↗
PubMed1987

Provocative dose and dose-response curve to inhaled propranolol in asthmatic patients with bronchial hyperresponsiveness to methacholine.

This study was carried out to compare bronchial responses to inhaled propranolol (P) and methacholine (M) in a group of asthmatic subjects with mild to moderate bronchial hyperresponsiveness to M; to determine the short term reproducibility of bronchial response to propranolol; and to examine the shape of dose-response curve to P relative to that of M. Doses of M and P were given in mumoles and bronchial responses to both agents were expressed as the provocative dose that induced a 20 percent fall in FEV1 (PD20 FEV1). In 16 asthmatic patients, there was no correlation between the PD20 of the two agents. Mean PD20 M (+/- SD in log scale) was approximately nine times lower than mean PD20 P (0.64 +/- 0.96 and 5.80 +/- 1.65, respectively). This difference was statistically significant (t = 4.58, p less than 0.001). In six asthmatic patients, the reproducibility of PD20 P was similar to that of M (intraclass correlation coefficient 0.969 and 0.957, respectively). The shape of the dose-response curves to P was different from that of M in five of nine asthmatic patients when all experimental points were analyzed by double-reciprocal plot. We noticed that even small doses of inhaled P may cause a severe bronchoconstriction. Therefore, special caution should be taken to increase P doses very gradually, when studying the dose-response curve. We demonstrated that P inhalation induced a measurable bronchoconstriction in subjects with mild to moderate hyperresponsiveness and it was reproducible. However, the bronchial sensitivity to P was lower than to M. Our findings suggest that P and M have different mechanisms of action.

Asthma↗
PubMed1987

Refractory period to ultrasonic mist of distilled water: relationship to methacholine responsiveness, atopic status, and clinical characteristics.

Twenty asthmatic subjects had two successive methacholine challenges, two successive challenges with ultrasonically nebulized distilled water (UNDW) and an UNDW followed by methacholine on three separate days. Only ten subjects showed a refractory period to repeated UNDW stimulation. Prior stimulation with UNDW provoked increased methacholine responsiveness in the non-refractory group and a more rapid recovery from methacholine-induced bronchoconstriction in the refractory subset.

Adult↗
PubMed1986

Late bronchial response and increase in methacholine hyperresponsiveness after exercise and distilled water challenge in atopic subjects with asthma with dual asthmatic response to allergen inhalation.

We investigated the occurrence of late asthmatic response and increased methacholine responsiveness after exercise and ultrasonically nebulized distilled water (UNDW) inhalation in 12 subjects with asthma with dual asthmatic response and increased responsiveness after allergen challenge. On 3 separate days, allergen, exercise, and UNDW challenges were performed 2 hours after methacholine. FEV1 was measured for 8 hours to detect any delayed change in airway caliber. If there were a further significant reduction in FEV1 after the recovery from the immediate bronchoconstriction, methacholine challenge was performed again when FEV1 had returned to baseline. Reproducibility of any observed late response to exercise and UNDW was also investigated by repeating these challenges on 2 subsequent days. After allergen inhalation only nine subjects had an early asthmatic response, whereas all the tested subjects demonstrated a late reaction and increased methacholine responsiveness. Ten subjects had an immediate response to exercise, and this was followed by a late response in only four patients. Nine subjects demonstrated early response to UNDW inhalation, and five subjects also had a late reaction. These late responses were associated with an increase in methacholine responsiveness in a subset of the tested subjects. Late-phase reactions to exercise and UNDW were not reproducible.

Administration, Inhalation↗
PubMed1986

Dose-response relationship: fenoterol, ipratropium bromide and their combination.

The beta agonist fenoterol, the antimuscarinic ipratropium bromide and their combination were compared in 10 patients with stable reversible airway obstruction. A single-blind cross-over design was used in order to obtain cumulative dose-response curves. The dose inhaled by an IPPB apparatus on different days were: fenoterol, from 12.5 to 1.600 cumulate micrograms; ipratropium bromide, from 5 to 640 cumulate micrograms; combination (5:2), from 17.5 to 1.120 cumulate micrograms. The bronchodilator effect was measured as changes of FEV1 and of SGaw. Data were processed in order to identify the median effective dose (ED50) and the percentage change at ED50 (RED50). The mean ED50 in micrograms (+/- SD) resulted in: Fenoterol, ED50 (FEV1) = 132 (+/- 46); ED50 (SGaw) = 172 (+/- 62); Ipratropium bromide, ED50 (FEV1) = 14 (+/- 7); ED50 (SGaw) = 23 (+/- 11); Combination, ED50 (FEV1) = 109 (+/- 26); ED50 (SGaw) = 121 (+/- 53). The mean RED50% (+/- SD) resulted in: Fenoterol, RED50 (FEV1) = 30 (+/- 16); RED50 (SGaw) = 106 (+/- 78); Ipratropium bromide, RED50 (FEV1) = 21 (+/- 10); RED50 (SGaw) = 82 (+/- 66); Combination, RED50 (FEV1) = 35 (+/- 11) RED50 (SGaw) = 135 (+/- 81). The ED50 (FEV1) of the combination was significantly lower (p less than 0.05) than that of fenoterol. This increased potency of the combination supports evidence for an overadditive interaction between fenoterol and ipratropium bromide. Moreover, the efficacy of fenoterol (RED50) is enhanced by combining the two drugs.

Adult↗
PubMed1986

Increase in bronchial responsiveness to methacholine and late asthmatic response after the inhalation of ultrasonically nebulized distilled water.

We studied ten subjects who had an asthmatic response after the inhalation of ultrasonically nebulized distilled water and did not show any refractory period to repeated challenge with such water. The change in responsiveness to methacholine after inhalation of distilled water and the occurrence of any water-induced late asthmatic response were investigated on separate days. All of the tested subjects showed a significant increase in bronchial responsiveness to methacholine after prior stimulation with ultrasonically nebulized distilled water, which waned within two hours in eight of them. The other two subjects showed a progressive increase in responsiveness to methacholine, and they also had a further reduction in the caliber of the airways three to four hours after inhalation of distilled water. The late responses were less severe than the initial responses and lasted four to five hours. After the spontaneous recovery, no significant increase in responsiveness to methacholine was detected. Our results confirm previous observations on hyperresponsiveness induced by ultrasonically nebulized distilled water and demonstrate the occurrence of late reactions after inhalation of such water.

Aerosols↗