The hypothesis of Szentivanyi that bronchial asthma is associated with impaired 0-adrenoceptor function has been tested in several investigations in recent years. Most of these studies have been performed on leukocytes from peripheral blood, since these cells are easily accessible and since they are endowed with 0-adrenoceptors of the 02-subtype, as is human lung tissue. The interpretation of results from some of these studies is confounded by the findings that the (3-adrenoceptors of white blood cells are down-regulated by antiasthmatic therapy with β-adrenoceptor agonists. Such down-regulation of 0-adrenoceptors in white blood cells disappears within one week after discontinuation of treatment.
Twelve subjects were studied. All were wheezing at the time of study and all had moderate-to-severe airways obstruction with an FEV! between 720 ml and 1,500 ml. Table 1 shows the FEV, on pulmonary function tests done before and after bronchodilators, performed within four weeks of the lung sound recording.
In Europe, as on other continents, bronchial asthma is a common disorder with widely variable clinical features. It is frequently not diagnosed and, if diagnosed, its severity is often underestimated by the medical profession as well as by patients and their families. Failure to diagnose or to correctly estimate the severity leads to considerable undertreatment. Moreover, in few other chronic conditions have more divergent opinions been noted concerning the correct type and order of treatment to be applied to the chronic state of the disease, as well as to its acute exacerbations. This was also brought out by a pilot survey conducted on the basis of a questionnaire among 68 chest physicians from seven European countries during the summer of 1983; although clear patterns of responses emerged among the physicians of each country, there was considerable disagreement among countries on the proper choice and dosage of drugs and ventolin inhalers for asthma therapy. Because of the interest generated by the presentation and the discussion of this survey at the Second Annual Meeting of the European Society of Pneumology in Edinburgh, it was decided to enlarge the scope into a complete European Audit on Diagnosis and Treatment of Asthma, covering all major countries of western Europe and using an improved and extended questionnaire.
The prevalence of asthma and allergic disease has increased substantially during recent decades, and to a large extent the causes for this increase are still imperfectly understood. It is well recognized that the incidence of asthma is greater in childhood compared to adulthood, and that the male subject/ female subject ratio of incident asthma diminishes with increasing age. However, an interest in adult-onset asthma has emerged, not in the least due to reports coming from several large-scale longitudinal studies from Europe (European Community Respiratory Health Survey2) and the and United States (National Health and Nutrition Examination Study), pointing out the growing impact of adult respiratory allergic disease morbidity. No single hypothesis can explain this widened distribution of disease, but a biologically plausible model is likely to include environmental risk factors associated with a westernized lifestyle interacting with individual susceptibility genotypes. In a search for factors fitting such a model, several environmental determinants have been shown be part of the cause of adult-onset wheezing illness, including female sex, upper airway allergic disease, sensitization to aeroallergens,> obesity, exposures encountered at work, and perhaps hormone replacement therapy. Still, longitudinal data on incident asthma among adults are sparse, and the study of these data may therefore provide new insight into the development and natural history of the disease.