Dual pathway clearance of /sup 99m/Tc-DTPA from the bronchial mucosa

Journal Article · Mon May 01 04:00:00 EDT 1989 · Am. Rev. Respir. Dis.; (United States)

DOI:https://doi.org/10.1164/ajrccm/139.5.1132· OSTI ID:6080866

Bennett, W D; Ilowite, J S

Many studies have reported clearance rates of 99mTc-DTPA from the alveolar epithelial surface, but few have measured clearance of this solute from the bronchial mucosa. Those that have attempted such measurements have discounted the possibility that 99mTc-DTPA may be removed from the bronchial airways by mucocilliary transport as well as by absorption through the epithelium. This study was designed to better approximate the rate of 99mTc-DTPA absorption across the bronchial epithelium by correcting the measurements of total 99mTc-DTPA clearance for mucus transport. On two separate study days, each normal, nonsmoking subject (n = 8) breathed an aqueous aerosol (2.0 microns MMAD, sigma g = 2.0) containing 99mTc bound to DTPA or human serum ablumin (HSA) (a relatively nonpermeable solute that is cleared only by mucus transport over the period of measured clearance) while seated in front of a gamma camera. Breathing pattern was standardized to produce a similar central deposition of particles on both study days. From measurements of retention versus time over a 1-h period, exponential rate constants (Ktot and Km) were determined for the clearance of 99mTc-DTPA and 99mTc-HSA, respectively. By modeling the airways as a single compartment with two possible routes of clearance, we determined the permeability rate constant, Kp, as Ktot minus Km. Results showed that mucus clearance (Km) accounted for two thirds of the total rate of 99mTc-DTPA clearance (Ktot) (mean Ktot = 0.00985, Km = 0.00698, and Kp = 0.00287/min).

• Research Organization: SUNY at Stony Brook, New York, NY (USA)
• OSTI ID: 6080866
• Journal Information: Am. Rev. Respir. Dis.; (United States), Journal Name: Am. Rev. Respir. Dis.; (United States) Vol. 139:5; ISSN ARDSB
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ABSORPTION
AEROSOLS
AMINO ACIDS
ANIMAL TISSUES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL HALF-LIFE
BIOLOGICAL PATHWAYS
BODY
BRONCHI
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CELL MEMBRANES
CHELATING AGENTS
CLEARANCE
COLLOIDS
DISPERSIONS
DRUGS
DTPA
EPITHELIUM
EXCRETION
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
ISOMERIC NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LUNG CLEARANCE
MAMMALS
MAN
MEMBRANES
MUCOUS MEMBRANES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
PERMEABILITY
PRIMATES
RADIOISOTOPES
RADIOPROTECTIVE SUBSTANCES
RESPIRATORY SYSTEM
RETENTION
SOLS
TECHNETIUM 99
TECHNETIUM ISOTOPES
TISSUES
TRACER TECHNIQUES
VERTEBRATES
YEARS LIVING RADIOISOTOPES