Prevalence of contact dermatitis among dental personnel in a Swedish rural county.

The use of acrylate-based polymers in dental care in Sweden has increased dramatically in recent years. Acrylate monomers are sensitizers and can cause contact dermatitis. Allergy to latex, e.g. in rubber gloves, is also an increasing problem in health care and especially in dental care. The aim was to estimate the prevalences of work related allergies in dental personnel in a Swedish county with almost 700 dentists, dental nurses and dental hygienists. A questionnaire was distributed to all dental care units in the county and 98% of the population completed it. Specific allergy was verified with standard patch and prick testing. Work related allergy symptoms were reported by 189 subjects, 28%. The prevalences of acrylate eczema and latex allergy were 3,0% and 3,7% respectively. The prevalence of all work related skin allergy was estimated to 8%. The estimated prevalence of acrylate allergy was close to those of a few other published reports. However, the prevalence of hypersensitivity to latex rubber was lower than those reported from other studies. It is concluded that almost one dental care worker out of ten has a risk of contact dermatitis, unless measures to reduce hazardous exposure have been taken.

Deposition and clearance in large and small airways in chronic bronchitis.

Tracheobronchial clearance was studied twice in 16 patients with chronic obstructive bronchitis after inhalation of 6 microns (aerodynamic diameter) monodisperse Teflon particles labeled with 111In. At one exposure the particles were inhaled at an extremely slow flow, 0.05 L/s; at the other they were inhaled at a normal flow, 0.5 L/s. Theoretical calculations and experimental data in healthy subjects indicate particle deposition mainly in the smallest ciliated airways using 0.05 L/s, i.e., in the bronchiolar region, and an enhanced deposition in larger airways using 0.5 L/s. Lung retention was measured at 0, 24, 48 and 72 h. Clearance was significantly every 24 h for both exposures (p < .05). The fractions of retained particles were significantly larger for particles inhaled at 0.05 L/s compared to 0.5 L/s at all points of time (p < .001). Compared to healthy subjects, the retained fractions of deposited particles were larger in patients with bronchitis breathing at 0.05 L/s, but smaller with breathing at 0.5 L/s (p < .01). Significant relationships were found between lung retentions and airway resistance (Raw) at 0.5 L/s, r = -.68 (p < .01), but not at 0.05 L/s, and between lung retention at 24 h and weight of expectorated sputum at 0.05 L/s, r = -.50 (p < .05). There was, furthermore, an almost significant relationship between sputum volume and rate of tracheobronchial clearance between 0 and 24 h (in percentage of the total amount cleared during 72 h) at 0.05 L/s, r = .42 (p = .05). The results indicate that in patients with chronic bronchitis overall clearance of particles in small airways is incomplete, as compared to larger airways. An increased amount of mucus, however, seemed to improve clearance of peripherally deposited particles, possibly by making cough more effective in small airways.

Repeatability of airway deposition and tracheobronchial clearance rate over three days in chronic bronchitis.

Previous investigations on tracheobronchial clearance in chronic bronchitis or chronic obstructive pulmonary disease (COPD) have usually referred to measurements during a short time-period, i.e. a few hours. The purpose of this study, therefore, was to study regional particle deposition and tracheobronchial clearance during 72 h. In 14 patients with chronic bronchitis clearance of 111In-labelled 3.6 micrograms Teflon particles and lung function were measured on two occasions, with an interval of 2 weeks. Lung retention of test particles was measured at 0, 24, 48 and 72 h using a profile scanner. The weight of expectorated sputum samples was measured after the two clearance measurements. The particle retentions at all time-points were reproducible, as seen from the two measurements ( r > 0.90). The fast clearance phase was completed within 72 h. No correlation between sputum volume and clearance was seen. There was a significant negative correlation between airway resistance and the 72 h retention (r= -0.66), and an even better correlation between specific airway resistance and the 72 h retention (r = -0.82), indicating more central deposition in obstructed airways. There was no significant correlation between lung function tests reflecting smaller airways and the 72 h retentions. Deposition data agreed well with theoretical calculations and experimental data in healthy subjects. In spite of earlier findings that mucociliary transport is usually severely impaired in chronic bronchitis and COPD, the present results indicate that overall tracheobronchial mucus clearance in these patients is fairly effective, probably due to a productive cough. Alveolar deposition may be estimated by measurements of the 72 h retention in subjects with chronic obstructive pulmonary disease. The 72 h retention is dependent mainly on the calibre of larger airways. The present method of studying airway clearance during 3 days is highly reproducible.

Bronchial reactivity, lung function, and serum immunoglobulin E in smoking-discordant monozygotic twins.

Smokers with chronic bronchitis and/or chronic obstructive pulmonary disease (COPD) have been reported to have an increased bronchial reactivity (BR). It has been discussed whether increased BR is a risk factor for the development of COPD in smokers. We studied 10 monozygotic twin pairs who were discordant for tobacco smoking by means of histamine provocation tests, lung function tests, and serum samples for total IgE. The smokers had a mild obstructive ventilatory impairment, with FEV1 significantly lower than that of the partner both when it was determined from the flow-volume loops (3.2 +/- 1.0 L for smokers and 3.4 +/- 0.8 L for nonsmokers) and by the Vitalograph spirometer (3.5 +/- 1.0 L for smokers and 3.8 +/- 0.8 L for nonsmokers). Forced midexpiratory flow (FEF25-75%) and forced expiratory flow at 75 to 85% of vital capacity (FEF75-85%) were both significantly lower in the smokers (p < 0.05). The alveolar plateau phase N2-delta test and lung clearing index in the multibreath nitrogen washout test were both significantly affected in the smokers (p < 0.05 and p < 0.01, respectively). We found no significant difference in histamine reactivity between smokers and nonsmokers and no correlation between differences in reactivity and differences in lung function within pairs. Total serum IgE was significantly higher in the smokers than in their nonsmoking siblings. These data suggest that obstructive ventilatory impairment and raised serum IgE are earlier and more constant manifestations of tobacco smoking than increased bronchial reactivity. Thus, bronchial hyperreactivity does not seem to be a major risk factor for the development of early airways obstruction in smokers.

Bronchodilator intake and plasma levels on admission for severe acute asthma.

We have measured the plasma levels of salbutamol, terbutaline and theophylline in 140 patients (70 men, mean age 57 yrs) arriving for emergency treatment with severe acute asthma. The aim of the study was to investigate how the measured plasma levels correlated with the reported bronchodilator intake and whether the pretreatment beta 2-agonist levels influenced the effect of emergency salbutamol treatment. We found a highly significant correlation between the reported 24 h dose and the measured plasma concentrations for all three drugs. A plasma concentration less than 40 mumol.l-1 was found in 63 of the 107 patients who had taken theophylline, while no patient had a plasma concentration greater than 110 mumol.l-1. A plasma concentration above the suggested therapeutic range was found in 23 of the 95 patients who had taken terbutaline (greater than 30 nmol.l-1) and in 12 of the 98 patients who had taken salbutamol (greater than 60 nmol.l-1). A significant negative correlation was found between the initial plasma beta 2-agonist levels and the bronchodilation after i.v. salbutamol treatment (5 micrograms.kg-1), while there was no clear indication that high plasma beta 2-agonist levels reduced the bronchodilator effect of a high dose of inhaled salbutamol (0.15 mg.kg-1 x 2). We conclude that some patients arriving with acute asthma have high blood concentrations of beta 2-agonists, which possibly limit the response to i.v. beta 2-agonist treatment, while the effect of high-dose inhaled beta 2-agonists appears to be related to a lesser degree to the drug concentration on arrival. In this study overtreatment with theophylline appears to be uncommon.

Bronchial reactivity and allergy-promoting factors in monozygotic twins discordant for allergic rhinitis.

Bronchial reactivity was studied twice in eight monozygotic twin pairs discordant for allergic rhinitis with pollen hypersensitivity, during the winter season (all eight pairs) and during the pollen season (seven pairs). On both occasions, the allergic twins showed significantly higher reactivity than their nonallergic siblings. The results indicate that moderate allergic rhinitis is associated with increased bronchial reactivity. This increased reactivity is an acquired trait; however, bronchial reactivity is not constantly increased in pollen rhinitis and may be normal even during the pollen season. The symptoms of allergic rhinitis usually started in childhood before the separation of the siblings. We could not demonstrate any major differences in exposure to allergens or airway irritants between the siblings. The allergic twins tended to have lower birth weight and insufficient weight increase just after birth.

Bronchial reactivity and atopy in asthma discordant monozygotic twins.

Bronchial reactivity was studied in six asthma-discordant monozygotic twin pairs. In four pairs, atopy was confirmed in the asthmatic twin. It was not confirmed in any of the nonasthmatics. In five pairs, the asthmatic twin was markedly more reactive than the nonasthmatic partner. Bronchial reactivity correlated significantly with total IgE. The results indicate that hyperreactivity and atopy were acquired.

Postural mechanisms in asthma: importance for nocturnal symptoms.

The supine position impairs ventilatory function in patients with ongoing asthma. The response is dual: an immediate decrease on lying down, present in healthy persons as well, and a progressive decrease specific for asthmatics. The changes are counteracted by bronchodilators, but are not linked to a decreased plasma adrenaline level when supine. The progressive decrease is tentatively explained by an increased vagal tone induced by the resting body position, and is likely to be a key factor in nocturnal asthma.

Tracheobronchial clearance in asthma-discordant monozygotic twins.

Tracheobronchial clearance and bronchial reactivity were studied in 6 asthma-discordant monozygotic twin pairs, and in 3 concordant pairs as controls. Clearance of 6-microns Teflon particles labeled with 99mTc was followed for 2 h. The results indicate that clearance in the larger airways is usually not severely impaired in mild to moderate asthma, and that it may be increased as well as decreased. Bronchial reactivity correlated with clearance in the nonasthmatics.

Posture-induced airflow limitation in asthma: relationship to plasma catecholamines and an inhaled anticholinergic agent.

Postural influence on ventilatory function was investigated in thirteen asthmatic subjects on three consecutive days starting at 10.00 am. Lung function was measured in the seated position before and after four hours lying supine. Peak expiratory flow (PEF) was measured every 0.5 h in the supine position. Blood samples for determination of plasma catecholamines were collected before, during and after lying supine. After the initial lung function testing, placebo or ipratropium bromide (0.125 mg) was inhaled. On the third day the whole trial was performed seated, without any drug, as a control experiment. On the placebo day lying supine induced an initial, rapid fall of PEF followed by a progressive decrease during the four hours. The progressive decrease in PEF was apparently caused by bronchoconstriction. Ipratropium bromide prevented this posture-induced bronchoconstriction. On the day seated there was also a tendency towards a decline of PEF though less pronounced than in the supine position on the placebo day. No significant alterations in plasma levels of catecholamines were observed. We conclude that the supine posture is a stimulus to bronchoconstriction in asthma, likely to be involved in nocturnal wheezing. Postural bronchoconstriction is not explained by lowered plasma levels of adrenaline, as has been suggested for nocturnal asthma. The results raise the question of whether cholinergic mechanisms are involved.

Influence of ambroxol on tracheobronchial clearance in simple chronic bronchitis.

The influence on tracheobronchial clearance of ambroxol, a metabolite of bromhexine, was investigated by measuring the lung retention of inhaled 6 micron monodisperse Teflon particles labelled with 99mTc. Fourteen subjects with simple chronic bronchitis, who belonged to a "responder" group in an earlier study on the subjective effects of ambroxol, were examined using a double-blind cross-over design comparing 120 mg ambroxol daily and placebo. On commencing the study and after each 2-week treatment period, the subjects were examined for mucociliary clearance and clearance by voluntary coughing. Treatment did not influence mucociliary clearance or clearance by cough. There is still a possibility that phlegm loosening by cough is enhanced in situations with more hypersecretion.

Ambroxol and simple chronic bronchitis. Effects on subjective symptoms and ventilatory function.

In a double-blind, randomized, controlled trial using parallel groups, we evaluated the effects of two dose levels of ambroxol (60 and 120 mg daily) versus placebo by means of pulmonary function tests, patients' diary cards, interviews on current airway symptoms and subjective drug effects in 92 subjects with simple hypersecretory chronic bronchitis. The treatment period was 2 weeks. Subjects in the 120-mg group compared to the placebo group reported improvement in respiratory symptoms (p less than 0.05), particularly in phlegm loosening (p less than 0.05) and tended to prefer the treatment period when compared to placebo (p = 0.056). Lung function values and diary cards did not indicate significant changes.

Ambroxol therapy in simple chronic bronchitis: effects on subjective symptoms and ventilatory function.

Ambroxol, a metabolite of bromhexine, was investigated in a double-blind, controlled trial using parallel groups. We studied the effects of 60 mg and 120 mg daily versus placebo in subjects with simple chronic bronchitis. Possible therapeutic effects were evaluated by means of interviews on subjective drug effects and current respiratory symptomatology, patient diary cards, and lung function tests. Ninety-seven subjects entered the study and 92 completed satisfactorily. Comparison with the placebo group at the end of the study showed that significantly more subjects in the 120 mg ambroxol group reported improvement in respiratory symptoms, principally improved expectoration. Subjects in the 120 mg group tended to prefer the treatment period when compared to placebo but the diary cards did not indicate significant changes. Lung function values were mainly normal and did not change during treatment. We conclude that the drug had a symptomatic effect and that further studies in more severely affected patients would be worthwhile.

Mucociliary clearance in relation to clinical features in patients with bronchiectasis.

Patients with bronchiectasis were collected from a register covering all hospital stays within the county of Stockholm. They were asked to come for an interview, a clinical examination and to participate in a study of lung mucociliary clearance. The subjects inhaled 6 microns Teflon particles labelled with 99mTc and radioactivity was measured externally. Clearance varied from normal to extremely slow. The average retention of the Teflon particles at 2 h was significantly higher in the 21 patients, 65 +/- 27% (mean +/- SD), than in healthy nonsmokers, 36 +/- 22%. Clearance was more impaired the more generalized the airway symptoms were, the more continuous they were, and the earlier in life they had started; all features which indicate a coherence with the immotile cilia syndrome, an obvious "model disease" in this context. Clearance was studied separately in the two lungs in 18 patients and was similar in both lungs, with one exception.