Dose Estimation for Studies of Acute Respiratory Effects

This study has been completed.
Sponsor:
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI)
ClinicalTrials.gov Identifier:
NCT00005362
First received: May 25, 2000
Last updated: June 23, 2005
Last verified: May 2000

May 25, 2000
June 23, 2005
September 1992
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Complete list of historical versions of study NCT00005362 on ClinicalTrials.gov Archive Site
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Dose Estimation for Studies of Acute Respiratory Effects
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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.

BACKGROUND:

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.

DESIGN NARRATIVE:

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.

Observational
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Lung Diseases
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Woskie SR, Eisen EE, Wegman DH, Hu X, Kriebel D. Worker sensitivity and reactivity: indicators of worker susceptibility to nasal irritation. Am J Ind Med. 1998 Dec;34(6):614-22.

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Completed
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August 1995
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No eligibility criteria

Male
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No
Contact information is only displayed when the study is recruiting subjects
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NCT00005362
4249
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National Heart, Lung, and Blood Institute (NHLBI)
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National Heart, Lung, and Blood Institute (NHLBI)
May 2000

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP