Effects of rhDNase on purulent airway secretions in chronic bronchitis.

Recombinant human deoxyribonuclease (rhDNase) has been demonstrated to reduce in vitro the viscosity and to improve the transport capacity of purulent respiratory mucus in cystic fibrosis. During episodes of exacerbation of chronic bronchitis, the patients generally expectorate purulent mucus. Purulence of mucus is associated with an increased deoxyriboneucleic acid (DNA) concentration. We analyzed in vitro the potential effect of rhDNase on chronic bronchitis mucus transport by the ciliary activity (frog palate model) and by simulated cough (cough machine model), as well as the effect on mucus viscosity (controlled stress rheometer) and surface properties (contact angle). Purulent sputa collected from patients with chronic bronchitis (n = 15) during an episode of exacerbation were incubated for 30 min at 37 degrees C with either rhDNase at two different concentrations (final concentration 2 or 4 micrograms.mL-1) or placebo. The median mucociliary transport rate was significantly improved by rhDNase from 0.68 with placebo to 0.79 and 0.83 with 2 and 4 micrograms.mL-1 of rhDNase, respectively. A significant improvement in mucus cough transport was also induced by rhDNase from 25.5 mm with placebo to 27.0 mm with either 2 or 4 micrograms.mL-1 rhDNase. These improvements in mucus transport capacity were associated with alterations in the physical properties of the mucus. The mucus median control viscosity (511.4 Pa.s) and median contact angle (0.85 rd) significantly decreased to 112.5 Pa.s and 0.74 rd, respectively, in the presence of 4 micrograms.mL-1 of rhDNase. These findings demonstrate that recombinant deoxyribonuclease may exert a beneficial effect on mucus clearance in vitro by altering the viscosity and surface properties of the purulent chronic bronchitic sputum samples.

[Quantitative bacteriology of sputum collected by a simple technic limiting salivary contamination]. / Bactériologie quantitative des expectorations recueillies par une technique simple limitant la contamination salivaire.

A simple non-invasive method to improve the reliability of bacteriological analyses of sputum was evaluated in 25 patients with chronic bronchitis. This method consists of placing dental cotton swabs between the cheek and the gum and under the tongue at the level of the excretory salivary glands. Once these plugs are in place, the sputum is collected by coughing under the control of a physiotherapist. The quantitative bacteriological data from sputum collected by the "protected" and "unprotected" methods were compared with those from bronchial secretions collected by transtracheal aspiration, used as reference method. Oropharyngeal cells and commensal bacteria were isolated at a significantly lower frequency in sputum collected by the protected method. Considering the predominant pathogenic bacteria, an excellent correlation was obtained between transtracheal aspiration and sputum in 80% of cases when sputum was collected by protected method and in 68% of cases by unprotected method. In four patients, the transtracheal aspiration was sterile, while a potentially pathogenic organism associated with a high leukocyte numeration was identified in sputum. All the potential pathogens isolated in the positive transtracheal aspiration were recovered in the protected sputum (100%), but they could be associated with a non-predominant commensal flora (11 cases) or a potentially misleading pathogenic bacteria (2 cases).