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Biomedical subjects

E Puchelle

Publications and source records attributed to E Puchelle.

At least 199 records · Page 11Linked to original sources
PubMedDate not supplied

Toxic effects of sulfur mustard on respiratory epithelial cells in culture.

Sulfur mustard (SM) is known to induce cutaneous injury and to cause acute damage to the respiratory tract. Although skin vesication has been demonstrated on human epidermal keratinocytes in culture, no study has been carried out to analyze the effects of SM on the ultrastructural and functional activity of surface respiratory epithelial cells. To evaluate this SM toxicity, we developed an in vitro model of respiratory epithelial cells in primary culture. The study was performed on surface epithelial cells from rabbit trachea cultured according to the explant-outgrowth technique. The functional activity of the cultures was evaluated by measuring the ciliary beating frequency (CBF) of the ciliated cells with a videomicroscopic method. The morphological aspects of the cells were analyzed by light and electron microscopy. Addition of 0.1 mM SM directly into the culture medium produced a sudden and irreversible CBF inhibition, first observed after 2 hr on the ciliated cells of the outgrowth periphery. The arrest of the ciliary beating progressively reached the whole surface of the outgrowth and was simultaneously observed with a detachment of the outgrowth cells. It began at the outgrowth border, leading to the exfoliation of cell sheets, and then to the whole culture after 48 hr. Morphological damage was expressed by intense vacuolisation and disorganization of cytoplasmic and nuclear structures. These findings suggest that the detachment of the respiratory epithelial cells from the matrix represents a major toxic effect of 0.1 mM SM. SM dramatically affects the viability of respiratory epithelial cells in culture. Moreover, the sudden CBF inhibition is more likely due to the death of the ciliated cells than to a specific ciliotoxic effect of SM.

Animals↗
PubMedDate not supplied

Evaluation of the 99mtechnetium labelling effect on Pseudomonas aeruginosa surface properties.

Gamma emitter isotopes present some advantages over beta emitters as radioisotopic microbial labels. The labelling of bacteria with 99mtechnetium (99mTc) has recently been described. However, it was not ascertained whether the labelling process modifies microbial physicochemical surface properties important in the interaction between bacteria and eukaryotic cells. In the present study, we evaluated the effect of the labelling process on Pseudomonas aeruginosa surface charge, hydrophobicity, adherence to human buccal epithelial cells and phagocytosis by human leukocytes. No significant differences in electrophoretic mobility or cationized ferritin distribution was observed on the cell surface of labelled and unlabelled bacteria. 99mTc labelling did not modify the hydrophobicity adhesiveness or phagocytosis of P. aeruginosa. It is concluded that bacterial labelling with 99mTc may be a useful method for the numeration of bacteria and the analysis of their functional properties.

Bacterial Adhesion↗
PubMedDate not supplied

Effect of growth on surface charge and hydrophobicity of Staphylococcus aureus.

Modifications in the surface charge and hydrophobicity of Staphylococcus aureus Oxford during growth were studied by analysing electrophoretic mobility and adherence to hydrocarbons (hexadecane), respectively. Bacterial concentration had no effect upon the measurements. Both surface charge and hydrophobicity varied during the exponential phase of growth (1 to 4 h): surface charge decreased significantly (p less than 0.001), while hydrophobicity increased (p less than 0.001). In the stationary phase (4 to 9 h), the surface charge increased significantly (p less than 0.001), whereas hydrophobicity showed no change. Cationized ferritin decreased the surface charge and had no effect on hydrophobicity. These results suggest that in S. aureus, different structures could be responsible for their surface charge and hydrophobic properties.

Alkanes↗
PubMedDate not supplied

Comparison of three methods for measuring nasal mucociliary clearance in man.

Three techniques for studying nasal mucociliary clearance have been compared in 20 normal subjects, aged 19 to 26. Three different tracers used were deposited on the septum or the nasal floor. The transport rate of a 250 micron anion resin particle tagged with 99mTc was measured over a distance of 3.5 cm. This method was used as reference. The transport time of saccharin was measured when the subjects tasted its sweetness on swallowing. The transport time of 600 micron aluminium discs was measured by observing their arrival at the pharynx. For each method, duplicate measurements were carried out over a 24 hour period. Despite the large variations in the results from one day to the next, a significant negative correlation (r = -0.59, p less than 0.001) was observed between the transport rate of the radioactive particles and the transport time of the saccharin. The daily variations in nasal clearance for these two methods were also significantly correlated (r = -0.53, p less than 0.02). These results validate the suitability of the saccharin method as a simple screening test for detecting abnormally low values of nasal mucociliary clearance. In our group of 20 subjects, 5 were characterized by a low nasal mucociliary clearance, whichever method was used.

Adult↗
PubMedDate not supplied

[Structure and secretory functions of the respiratory epithelium].

Airway secretions actively participate in respiratory epithelium protection. Apart from its main participation in transport of inhaled microorganisms and particles by mucociliary clearance, respiratory mucus also contributes to other protective purposes such as the control of airway humidification. Biochemical components found in secretions, such as mucins, lipids, antibacterial agents (secretory IgA, lysozyme, lactoferrin), antioxidant and antiprotease components, contribute significantly to the airway epithelium defense.

Cells, Cultured↗
PubMedDate not supplied

[Morphogenesis and modifications of the respiratory epithelium].

The tracheobronchial tree begins to form during the fourth week of development through a series of dichotomic divisions of an entoblastic evagination. The morphogenesis and maturation of the respiratory tract depend both on the nature of the extracellular matrix which facilitates cell migration and on epithelial-mesenchymal interactions which induce the proliferation and differentiation of epithelial cells. The study of the plasticity and the phenotypic modifications of secretory cells during both development and inflammatory remodeling of the tracheobronchial mucosa suggests an important role for secretory cells during ciliogenesis and repair.

Bronchi↗
PubMedDate not supplied

Dynamics of cell movement during the wound repair of human surface respiratory epithelium.

Epithelial wound repair represents an important process by which the epithelial barrier integrity recovers after wounding. To evaluate and quantify the dynamics of surface airway cell movement during the wound repair process, we developed an in vitro wounding model of human respiratory cells in culture and we analyzed the wound repair by using videomicroscopic and image analysis techniques. We observed that wound closure occurred within 6 hours, due to the spreading and migration of the cells surrounding the wounded surface. The migration rate of the cells at the leading edge of the wound surface increased progressively up to 26 microns/h during the repair process which was characterized by a uniform centripetal direction of cell movement. The distance travelled by these cells was 2.5 fold longer than the distance travelled by ciliated cells which were located far from the wound area. These results suggest that cell migration after wounding is an important process by which the respiratory epithelial barrier integrity is maintained.

Cell Movement↗
PubMedDate not supplied

[Rheology of bronchial secretions and mucociliary transport (author's transl)].

Optimal relationships between mucociliary clearance and rheological properties of bronchial secretions expectorated by patients with chronic bronchitis have been analysed by successive measurements of visco-elasticity with a rotational rheometer and of transport velocity on frog palate mucosa. It appears that the role of the elastic component is predominent. Sputum characterized by very low strain recovery (SR less than 4 units) or conversely by very high elasticity (SR greater than 20 units) is transported at a low rate in comparison to that of the control frog mucus (relative transport rate less than 0.5). Pronounced hyperviscosity of sputum (no greater than 200 poises) appears also as a limiting factor to the mucociliary transport. The best transported secretions (relative transport rate greater than 0.7) are characterized by a relative elasticity (SR) of 4 to 13 units and a viscosity (no) of 25 to 200 poises. Under the action of mucolytic agents such as N-acetylcysteine, sputum initially characterized by low strain recovery (SR less than 4 units) is transported at a much slower rate which is related to the increased loss of elasticity. These results indicate that mucolytic drugs must be administered with great care in patients with chronic bronchitis. Moreover, they should not be used in patients with very low visco-elastic secretions which reflect the non-functional state of the bronchial mucosa.

Acetylcysteine↗
PubMedDate not supplied

[Pathophysiology of chronic, bronchial hypersecretion (author's transl)].

The biochemical and rheological analysis of sputum allows one to detect abnormalities of the bronchial secretion and to describe the development of the bronchial disease. The main biochemical components of sputum and their biological activities are first described. The fibrillar structure of the mucus is related to heavy weight glycoproteins and these macromolecules contribute to the viscoelastic properties of the bronchial secretion, by their capacity to combine with other proteins such as secretory immunoglobulin A (S-IgA). As the chronic bronchial hypersecretory state progresses, the glandular synthesis of mucins and/or secretory proteins decreases while the passive filtration of blood-derived proteins, such as serumalbumin, increases. Such biochemical changes are frequently associated with a rise in viscosity and a loss in elasticity of sputum. These rheological modifications result in an impairment of the mucociliary clearance and therefore contribute to airway obstruction. The assessment of different indices such as the equilibrium in mucin secretion, S-IgA/serum-albumin ratio, viscosity and elasticity of sputum and its mucociliary transport rate, should lead to a better knowledge of the defense properties of the bronchial mucosa.

Bronchi↗
PubMedDate not supplied

Apical structure of human respiratory cilia.

The apical structure of human respiratory cilia was studied using thin and thick sectioning techniques. The distal end of the mature cilium is narrowed and presents dense material and a crown-shaped glycocalyx. The crown is composed of three to seven bristles, having a mean length of 31 nm and showing a periodic structure. The capping structure of the apical part of human respiratory cilia is composed of a plate and an electron-dense cap tightly bound to the central and to each of the nine peripheral A microtubules. Lateral spokes link the peripheral microtubules to the internal ciliary plasma membrane and dense filaments radiate from the dense cap to the ciliary crown. These ciliary apical structures may be involved in several functions associated with microtubule assembly as well as ciliary movement and mucociliary transport.

Adolescent↗
PubMedDate not supplied

Spinability of respiratory mucous. Validation of a new apparatus: the Filancemeter.

Spinability is the ability of various biological fluids to be drawn into threads when stretched. This rheological parameter is of particular importance in the mucous transport process and can be easily measured using a newly commercialized apparatus: the Filancemeter. The measurement limits and the volumes of the samples used are presented. By studying the effect of sample volume on spinability, the importance of using well-calibrated samples is demonstrated. For the small volumes of sample (less than 5 microliters), the reproducibility of the measurement is low (coefficient of variation: 63% with 1 microliter sample), whereas it is significantly improved with larger volumes (coefficient of variation: 16% with 5 microliters sample). The measurements on respiratory mucous are in good agreement with the results obtained with a previous apparatus using a clip as a prehension system of the sample. With fluids exhibiting low viscosity like saliva, the higher values obtained with the Filancemeter can be attributed to a better prehension of the sample. This apparatus appears to be suitable for measuring the spinability of various biological fluids such as mucous.

Equipment Design↗