European journal of respiratory diseases. Supplement最新文献

The study of proteinases and their inhibitors in lung secretions may provide an understanding of the pathogenesis of many chronic lung diseases. However problems arise in the collection and assessment of the samples that leads to variability both within and between subjects. The purpose of the paper is to highlight these problems as well as the methods used to overcome them in secretions obtained from patients with chronic obstructive bronchitis. The results show that between subject variability is high; and may be up to 150% within an individual. Conventional means of reducing variability (standardisation for albumin) may not be appropriate for some proteins, leading to increased variability. The function of inhibitors is probably best expressed as enzyme inhibited/unit of inhibitor though even this shows daily variability within the same individual. An awareness of such variability is necessary for the interpretation of results obtained from patients.

This review briefly summarizes our knowledge of the composition of pulmonary surfactant and the mechanisms involved in its biosynthesis. The currently available evidence suggests that dipalmitoylphosphatidylcholine, the major surface-active component of surfactant, can be synthesized in the alveolar type II pneumocyte via two pathways: (1) by direct synthesis de novo via the CPDcholine route, and (2) by remodelling of unsaturated phosphatidylcholines, most likely via a deacylation-reacylation mechanism. In addition, this paper focusses on recent findings concerning the biochemical characterization of lamellar bodies, the intracellular storage organelles of surfactant. Lamellar bodies from adult human lung contain a lamellar body-specific alpha-glucosidase--which should prove useful as a specific marker enzyme for this organelle.

In dairy farmers exposed to the microbes present in hay, precipitating antibodies against these microbes are frequently found regardless of the state of health of the farmer. The prognostic value of these antibodies for the future health and working ability of farmers was studied in a six-year follow-up survey of 292 farmers. During these six years, of the farmers aged 45-59 years in the primary survey, 14 men (22%) and 15 women (22%) had retired or changed occupation because of illness. Among the men, the presence of precipitins was negatively correlated with their working ability reported in the follow-up study. The risk of occupationally disabling respiratory disease was three times higher in men with precipitins against microbes present in mouldy hay than in precipitin-negative farmers of the same age. No similar correlation was found for women.

This study was based on a sample of 1,831 farmers with no symptoms of the lower respiratory tract, which was taken from a larger survey population of 12,056 farmers. Forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were determined cross-sectionally in connection with health examinations at local health centres. Background data, which included age, sex, height, presence of atopic symptoms, and smoking habits, were gathered in a postal survey conducted by the Social Insurance Institution of Finland. Mean FEV1 and mean FVC were adjusted for age, sex, and height; FEV1 was also adjusted for FVC. Although atopy (defined on the basis of past or present atopic dermatitis, including infantile eczema, and/or hay fever or other allergic rhinitis) had no effect on mean FEV1, mean FVC was lower in atopic than in non-atopic subjects. Both mean FEV1 and mean FVC were lower in smokers than in non-smokers. Smoking thus influenced both FEV1 and FVC, but affected FEV1 slightly more. The effects of atopy and smoking on FVC seemed to be additive. These results, which imply that atopy may predispose obstruction of small airways, match our previous finding that atopy and smoking increase the occurrence of chronic bronchitis additively.

The effect of the indoor feeding season for cattle on pulmonary function was studied in 91 randomly selected healthy, non-smoking dairy farmers who did not use personal dust respirators. All the farmers lived in the rural municipality of Pielavesi in eastern Finland. The reference group consisted of 90 healthy, non-smoking urban dwellers who were teachers randomly selected from all the teachers employed by the city of Kuopio (situated in the same administrative district as Pielavesi). Studies of pulmonary function included flow-volume spirometry and measurement of pulmonary diffusing capacity. Among farmers, even a follow-up period of only 6 months was long enough to reveal restrictive impairment in lung function; among teachers restrictive impairment was not found. No evidence of impairment of pulmonary diffusing capacity was found in either of the study groups during the follow-up. Among teachers, changes in lung function did not differ from those previously reported as physiologically normal.

Total concentrations of dust in the air of work environments were measured on 20 Finnish farms during 1980-82. On 8 farms the main line of production was dairy farming, on 5 farms it was pig farming, on 4 farms poultry farming and on 3 farms grain production. Dust was measured by the gravimetric method according to the Finnish standard. Results were compared to the threshold limit value (TLV), which for inorganic dust is 10 mg/m3, and for organic dust 5 mg/m3. Mean concentrations of dust in the breathing zone exceeded the TLV for organic dust in all farm buildings, piggeries and poultry yards with coops having the highest mean concentrations, 12.6 mg/m3 and 12.8 mg/m3, respectively. Mean total concentrations of dust during seed dressing, harrowing, rolling and emptying the grain drier were 31.4, 14.0, 18.2 and 20.0 mg/m3, respectively. During sowing and haymaking, the total concentrations of dust were also high occasionally.

The prenatal and postnatal therapeutic management of surfactant insufficiency are reviewed. Prenatal maternal glucocorticoid therapy promotes lung maturation and enhances lung surfactant levels in the neonate, but a minimum of 24 hr treatment is required and the therapy is of limited effectiveness even under optimal conditions. Relatively few women in premature labour are good candidates for glucocorticoid therapy. Research into combinations of glucocorticoids with hormones (e.g. thyroid), and adrenergic agents in progress. The authors are studying the effects of fibroblast-pneumonocyte factor (FPF) on the fetal lung surfactant system. Postnatal therapy with insufflated natural and artificial surfactants has been studied in several centres with varying degrees of success. Currently, the risk:benefit ratios favour attempts to reduce the risks of respiratory distress syndrome (RDS) by both prenatal surfactant induction and postnatal replacement therapy. Greater understanding of the underlying mechanisms should permit the establishment of more satisfactory treatment.