Dose Estimation for Studies of Acute Respiratory Effects

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00005362
Recruitment Status : Completed
First Posted : May 26, 2000
Last Update Posted : May 13, 2016
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI)

Brief Summary:
To modify and expand an existing pharmacokinetic model for nasal dose as well as to develop a new model to estimate tracheobronchial dose of an active agent for each subject in a study of acute respiratory health effects.

Condition or disease
Lung Diseases

Detailed Description:


Epidemiologic analysis of acute, reversible respiratory health effects is uncommonly performed, yet these are important health outcomes because acute responses by the respiratory defense system appear to represent one end of the continuum toward progressive, chronic and potentially disabling physiologic changes. Repeatable epidemiologic studies of dose-response relationships necessitate accurate measures of 'dose'. However, in occupational and environmental settings, exposure to a toxin is seldom found at identical concentrations and/or particle sizes among persons with the same activity patterns. In addition, air concentration does not account for factors such as clearance or metabolism which may alter the biologically effective tissue dose. These factors cause the target tissue dose of the toxin to vary greatly despite exposure to similar air concentrations.


The results of these toxicokinetic models were individual measures of tissue dose used in a 2-stage epidemiologic analysis which placed special emphasis on the definition of individual dose-response curves for exposure to an irritant dust, sodium borate, and the reversible effects of peak expiratory flow and irritant symptoms. A primary advantage of the two stage epidemiologic approach was that it permitted particular attention to be focused on the factors which determined the sensitivity (threshold) and reactivity (slope) for an individual. The use of tissue dose estimates were also compared to simple exposure measurements in the epidemiologic analysis to evaluate the efficacy of using dosimetric methods in epidemiologic studies.

The study completion date listed in this record was obtained from the "End Date" entered in the Protocol Registration and Results System (PRS) record.

Study Type : Observational
Study Start Date : September 1992
Actual Study Completion Date : August 1995

Information from the National Library of Medicine

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Ages Eligible for Study:   up to 100 Years   (Child, Adult, Older Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   No
No eligibility criteria

Publications: Identifier: NCT00005362     History of Changes
Other Study ID Numbers: 4249
R01HL048853 ( U.S. NIH Grant/Contract )
First Posted: May 26, 2000    Key Record Dates
Last Update Posted: May 13, 2016
Last Verified: May 2000

Additional relevant MeSH terms:
Lung Diseases
Respiratory Tract Diseases