[Pharmacology of mucociliary transport]. / La pharmacologie du transport mucociliaire.

Muco-ciliary transport is only effective because of the coordination of the ciliary beats (metachronous) and the harmony between mucus and cilia. The tip of the cilia is in contact with a jellyform layer of mucus propelled to the oropharynx. This jellyform layer has a complex rheological behaviour: it flows like a liquid and shapes like solid elastic. When the rheological properties of bronchial secretion are abnormal, mucociliary transport becomes inefficient. However, the most fluid secretions are not necessarily best transported, because the elasticity and viscosity to guarantee efficient muco-ciliary transport can only vary within defined limits. The mechanism regulating the ciliary beats is poorly understood; the bronchial secretions conduct impulses through the autonomic nervous system as well as mediators such as histamine and the metabolites of arachidonic acid. Mucociliary function may be studied either, directly through mucociliary transport or through mucociliary clearance. A fall in mucociliary activity can be produced by a primary ciliary disorder, by bronchial disease or the consequences of respiratory infection. General anaesthetics and Atropine slow mucociliary transport but Ipratropium bromide does not; Theophylline and sympathomimetics speed it up. The expectorants are mucolytics (proteolytic enzymes, N-acetyl-cysteine), there are agents to correct hydration anomalies of the bronchial secretion (water, hypertonic sodium chloride) iodides, antifibrins by substitution, anti-inflammatory agents and mucoregulatory agents (S-carboxymethylcysteine, bromhexine). The efficacy of the greater part of these expectorants has not been established in vivo by controlled therapeutic trials.

[Deposition of particles in the respiratory system]. / La déposition particularie dans l'appareil respiratoire.

Aerosols consist of two phases: a gas phase and particle phase, either liquid or solid. Mathematical modeling of the three principal processes (impaction, sedimentation and diffusion) which determine the amounts of deposition of particles at various levels of the respiratory system is in agreement with the majority of experimental data, the upper airways behaving as a very effective filter for particles with an aerodynamic diameter greater than 2 micron. Below such a diameter, particles are capable of being deposited at all levels along the tracheo-bronchial system or in the terminal respirator units. This scale of micronic aerodynamic diameters furthermore corresponds to atmospheric aerosols with a long duration (monodispersed aerosols). Such findings have obvious consequences both in terms of the physiopathology of respiratory disorders as well as the therapeutic or diagnostic use of aerosols. In order to better define the deposition of infra-micronic particles, we used the Liu and Whitby analyser for measurement of particle concentration for diameters of between 0.0042 micron and 0.75 micron. The aerosol inhaled was ordinary atmospheric air with a stable profile. The respiratory tract of the subject was free of any particles after 5 respiratory cycles through a filter. Overall, expired particle concentrations decreased exponentially with the increase in apnea at the end of inspiration. This decrease was all the more marked when pulmonary capacity was smaller. These findings were apparently related to the increased probability of deposition by diffusion as the dimension of the air spaces decreases.

[Intrapulmonary deposition of inframicron particles during inspiratory apnea (author's transl)]. / Déposition intrapoulmonaire des particules inframicroniques au cours de l'apnée inspiratoire.

An experimental approach of the intrapulmonary deposition of particles with a diameter below 1 micron, suspended in the surrounding atmosphere, was done on two normal subjects during inspiratory apnea with a Whitby impactor. The first results seem to agree with those of literature and confirm the importance of pulmonary morphometric factors in the deposition processes. Numerous methodological problems remain, but it appears that the technique would be useful to evaluate the likelyhood of deposition of submicron particles which are presently known to be pathogenic.

[Tracheo-bronchial and pulmonary depositions as measured by radioactive tracers. Study on healthy and pathological subjects (author's transl)]. / Dépositions trachéo-bronchique et pulmonaire mesurées par traceurs radioactifs. Etude dans un groupe de sujets sains et pathologiques.

The result of a study done on 52 subjects including a thorough ventilatory functional test and the radioisotopic measurement of inhaled particles deposition, by working out the TB/P ratio, revealed that: 1. giving aerosol needs an exacting technique when used for quantitative aims; 2. ratio TB/P is increased in patients with chronic broncho-pulmonary diseases, because of a predominantly tracheo-bronchial deposition of particles; 3. in patients with a satisfactory ventilatory function the TB/P ratio is increased; on the other hand in patients with ventilatory disorders, the ratio is normal. The repartition of particles deposition between the compartments TB and B depends therefore not only on factors involving ventilatory functional values but also on the physiopathological factors not included in them.

Changes of P50 in hypoxaemia, hypercapnia and polycythaemia: multivariate analysis.

Multivariate analysis of P50 changes in hypoxia, hypercapnia and polycythaemia was performed in an heterogeneous group of forty three patients: hypoxic subjects with or without hypercapnia, with or without polycythaemia and polycythaemic subjects without hypoxia. A statistical analysis was undertaken using comparison of the means, study of the correlations, principal component analysis, multiple regression and correspondence analysis. In the patients studied, P50 changes were not wholly explained by those of 2-3 DPG and pH; PaCO2, per se, did not play an important part. Haemoglobin concentration and P50 value would represent an adaptative mechanism to hypoxia: when hypoxia is moderate (80 greater than PaO2 greater than or equal to 65 torr) and isolated, oxygen haemoglobin affinity decreases (P50 increases); when hypoxia is severe (PaO2 less than 65 torr) and combined with hypercapnia and disturbed acid-base equilibrium, P50 comes back to normal range but haemoglobin increases, restoring thus, the normal blood oxygen content.

[Statistical study of the correlations between spirometric data and arterial blood gas tensions. II. During a 40-watt exercise (author's transl)]. / Etude statistique des corrélations entre les critères spirographiques et les pressions partielles d'oxygène et d'anhydride carbonique dans le sang artériel. II. A l'exercise musculaire de 40 w.

PaO2 and PaCO2, after 5 min of a 40-Watt exercise, and spirometric data have been statistically evaluated in 152 patients with chronic obstructive bronchitis. In these patients, the hypoventilation syndrome increases during exercise. The correlation between age and PaO2 is identical during rest and exercise, but the correlation between PaO2 or PaCO2 and FEV1 (% predicted) is closer during exercise than during rest. The value 50 of the FEV1 (% predicted) divides the patients into two groups: the patients who stay normocapnic and those who become hypercapnic or increase their hypercapnemia. These data show the interest of the FEV1 (% predicted) values and allow to explain the evolution of the arterial blood gas tensions during exercise.