The revised human respiratory tract model, published in Part 1 of the International Commission on Radiological Protection's (ICRP) report on Occupational Intakes of Radionuclides (OIR), includes a bound fraction, fb, to represent radionuclides that have become chemically bound in the lungs following dissolution of particulates in lung fluid. Bound radionuclides are not subject to particle transport clearance but can be absorbed to blood at a rate, sb. The occurrence of long-term binding of plutonium can greatly increase lung doses, particularly if it occurs in the bronchial and bronchiolar regions.
View Article and Find Full Text PDFRadiat Prot Dosimetry
December 2003
Values for the absorption parameters were compared after inhalation or intratracheal instillation of 1.5 microm mass median aerodynamic diameter (MMAD) 233U3O8 particles into the lungs of HMT strain rats. The two sets of parameter values were similar, as were the calculated dose coefficients and predicted biokinetics for workers.
View Article and Find Full Text PDFThe effect of oxitropium bromide on lung mucociliary clearance, pulmonary function and viscoelastic properties of sputum was investigated in 10 asthmatics and 10 chronic bronchitics. A controlled, double-blind, crossover study was performed. Following a baseline (B) measurement the patients were, in a random order, allocated placebo (P) or oxitropium bromide (O; 0.
View Article and Find Full Text PDFEight patients with Young's syndrome were treated with four "mucoregulatory" agents for eight weeks in a randomised, open crossover study. There was no improvement in tracheobronchial clearance, pulmonary function, or sperm count.
View Article and Find Full Text PDFOutput, droplet size (by laser instrument), and nebulization time have been compared in vitro for eight individual ultrasonic nebulizers (DeVilbiss Pulmosonic) and eight individual jet nebulizers (DeVilbiss 646), the latter operated by compressed air at flows of 6 and 12 L/min. A solution of hypertonic (7 percent) saline was nebulized. The ultrasonic nebulizer retained a higher "dead" volume of solution on completion of nebulization (p less than 0.
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