Effect of driving pressure and nebulizer model on aerosol output during intermittent delivery with a dosimeter

Hoarseness as a sign of possible nonspecific mucosal hyperreactivity in vocal tract

The aim of the present paper was to evaluate the possible impact of methacholine challenge on the voice and vocal tract in 10 patients reporting hoarseness due to presumable hyperreactivity to some environmental factors. Ten age and gender-matched healthy subjects served as controls. Methacholine was used for hypersensitivity challenge and saline solution (0.9% NaCl) as control substance. Subjects were examined on two separate challenge occasions testing either methacholine in increasing doses (3, 6, 12 mg) or NaCl. Voice recordings, videolaryngoscopy, and measurement of nasal secretion were performed before and after each sniffing session. Subjective complaints were documented. Data were statistically analyzed with three-way analysis of variance and group comparisons performed. Perceptual analysis of voice recordings showed an increase of the grade of voice disorder in patients after exposure to both substances. Moreover, one of the patients became aphonic and another severely dysphonic after NaCl. No voice quality changes were detected in controls. The videolaryngoscopy findings divergent from normal did not increase in any group. Nasal secretion was significantly higher after sniffing of methacholine than NaCl in both groups. The frequency of subjective complaints was equal in both groups after both substances. However, there was a qualitative difference in the character of the symptoms: the patients complained of throat, vocal, and nasal symptoms whereas the controls complained exclusively of nasal symptoms. The study supports the view that vocal dysfunction after exposure to non-specific environmental irritating factors may be triggered mainly by emotional mechanisms such as off-warding reaction or dissociative disorder.

Rationale for the Selection of an Aerosol Delivery System for Gene Delivery

Genetic therapeutics show great promise toward the treatment of illnesses associated with the lungs; however, current methods of delivery such as jet and ultrasonic nebulization decrease the activity and effectiveness of these treatments. Extremely low transfection rates exhibited by non-complexed plasmid DNA in these nebulizers have been primarily attributed to poor translocation and loss of molecular integrity as a consequence of shear-induced degradation. Current research focusing on methods to increase transfection rates via the pulmonary delivery route has largely concentrated on the incorporation of carbon dioxide in the air stream to increase breath depth as well as the addition of cationic agents that condense DNA into compact, ordered complexes. The purpose of this study was to examine the impact of several classic as well as the latest atomization devices on the structure of non-complexed DNA. Various sizes of plasmid and cosmid DNA were processed through an electrostatic spray, ultrasonic nebulizer, vibrating mesh nebulizer, and jet nebulizer. Results varied dramatically based upon atomization device as well as DNA size. This may explain the inefficiency experienced by genetic therapeutics during pulmonary delivery. More importantly, this suggests that the selection of an atomization device should consider DNA size in order to achieve optimal gene delivery to the lungs.