Aerosols respiratory tract

Tu, K.W. Knutson, E.O. (1984) Total deposition of ultrafine hydrophobic and hygroscopic aerosols in the human respiratory tract. Aerosol Science and Technology, 3, 453-65. 

Respiratory virus infections (respiratory syncitial virus [RSV], parainfuenza viruses, influenza viruses and adenoviruses) are all highly contagious and symptomatic individuals should be isolated before virologic confirmation is available. To prevent progression of RSV from the upper to the lower respiratory tract, aerosolized ribavirin may be used alone or in combination with RSV-specific antibodies or palivizumab, an RSV-specific monoclonal antibody (Boeckh et al., 2001). 

Industrial environments expose individuals to a plethora of airborne chemical compounds in the form of vapors, aerosols, or biphasic mixtures of both. These atmospheric contaminants primarily interface with two body surfaces the respiratory tract and the skin. Between these two routes of systemic exposure to airborne chemicals (inhalation and transdermal absorption) the respiratory tract has the larger surface area and a much greater percentage of this surface exposed to the ambient environment. Or dinary work clothing generally restricts skin exposures to the arms, neck, and head, and special protective clothing ensembles further limit or totally eliminate skin exposures, but breathing exposes much of the airway to contaminants. 

Airstream neutralization of acid aerosols by NH3 present in the airway-lumen reduces the health risk associated with acid particles by reducing the acid concentration prior to particle deposition.- In addition, the liquid lining of the respiratory tract probably acts as a chemical buffer," further reducing the health hazard posed by inspired acid particles. Principal factors controlling airstream neutralization of acid aerosols, which is considered to be a diffusion-limited process, are particle surface area, and particle... 

Scheuch, G., and Stahlhofen, W. (1992). Deposition and dispersion of aerosols in the airways of the human respiratory tract the effect of particle size. Exper. Lung Res. 18, 343-358. 

Buhl, R., Vogelmeier, C., Critenden, M., Hubbard, RC., Hoyt, RF., Wilson, E.M., Cantin, A.M. and Crystal, RG. (1990). Augmentation of glutathione in the fluid lining the epithelium of the lower respiratory tract by directly administering glutathione aerosol. Proc. Natl Acad. Sci. USA 87, 4063-4067. 

O The most common route of infection for endemic fungi is via the respiratory tract, where conidia aerosolized from contaminated soil are inhaled into the lung. 

Available information from human exposures indicates that airborne americium-containing particles are deposited in the respiratory tract, cleared to some extent via mucociliary action, and swallowed or expelled (Edvardsson and Lindgren 1976 Fry 1976 Newton et al. 1983 Sanders 1974 Toohey and Essling 1980). Descriptions of human respiratory tract models that can be used for radiation protection also include relevant information regarding biokinetics of inhaled particles (ICRP 1994b, 1995 NCRP 1997). Quantitative data are not available, however. Supporting animal studies include inhalation exposure to aerosols of americium (Buldakov et al. 1972 DOE 1978 Gillett et al. 1985 Sanders and Mahaffey 1983 Talbot et al. 1989 Thomas et al. 1972) or intratracheal instillation of americium compounds (Moushatova et al. 1996). 

The ICRP (1994b, 1995) developed a Human Respiratory Tract Model for Radiological Protection, which contains respiratory tract deposition and clearance compartmental models for inhalation exposure that may be applied to particulate aerosols of americium compounds. The ICRP (1986, 1989) has a biokinetic model for human oral exposure that applies to americium. The National Council on Radiation Protection and Measurement (NCRP) has also developed a respiratory tract model for inhaled radionuclides (NCRP 1997). At this time, the NCRP recommends the use of the ICRP model for calculating exposures for radiation workers and the general public. Readers interested in this topic are referred to NCRP Report No. 125 Deposition, Retention and Dosimetry of Inhaled Radioactive Substances (NCRP 1997). In the appendix to the report, NCRP provides the animal testing clearance data and equations fitting the data that supported the development of the human mode for americium. 

Field protection The principles applied to the nerve agents apply equally as well to the incapacitating agents. It is possible that such agents will be disseminated by smoke-producing munitions or aerosols, using the respiratory tract as a route of entry. The use of protective mask, therefore, is essential. The skin is usually a much less effective route. 

CS is disseminated by burning, explosion, and aerosol formation. It is immediately irritating to the eyes and upper respiratory tract. Warm vapors mix with human sweat to cause a burning sensation to the eyes, nose, and mouth. Conjunctivitis and pain in the eyes, lacrimation, erythema of the eyelids, runny nose, burning throat, coughing, and constricted feeling in the chest are the effects which will... 

Acute inhalation exposure to aerosols of certain polyalphaolefin hydraulic fluids produced death in rats associated with respiratory tract irritation, while aerosols of other polyalphaolefin hydraulic fluids produced no apparent respiratory tract irritation or deaths (MacEwen and Vemot 1983 Kinkead et al. 1987b, 1992b). The mechanism by which certain polyalphaolefin fluids may produce respiratory tract irritation is not understood. 

Drug delivery to the respiratory tract has been characterized in the past decade by an increase in knowledge of drug droplet or particle manufacture, behavior, aerosol dispersion, lung deposition and clearance. The number of diseases for which aerosol therapy may be applicable has increased dramatically. The pharmaceutical scientist is no longer limited to pulmonary diseases as therapeutic targets. Substantial progress has been made in every area of pharmaceutical aerosol science, and it is anticipated that this will ultimately lead to many new therapies. 

GA Ferron, G Oberdorster, R Henneberg. Estimation of the deposition of aerosolized drugs in the human respiratory tract due to hygroscopic growth. J Aerosol Med 2 271-283, 1989. 

PR Byron. Prediction of drug residence times in regions of the human respiratory tract following aerosol inhalation. J Pharm Sci 75 433-438, 1986. 

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