Passage of inhaled particles into the blood circulation in humans.
BACKGROUND
Pollution by particulates has been consistently associated with increased cardiovascular morbidity and mortality. However, the mechanisms responsible for these effects are not well-elucidated.


RESULTS
To assess to what extent and how rapidly inhaled pollutant particles pass into the systemic circulation, we measured, in 5 healthy volunteers, the distribution of radioactivity after the inhalation of "Technegas," an aerosol consisting mainly of ultrafine (99m)Technetium-labeled carbon particles (<100 nm). Radioactivity was detected in blood already at 1 minute, reached a maximum between 10 and 20 minutes, and remained at this level up to 60 minutes. Thin layer chromatography of blood showed that in addition to a species corresponding to oxidized (99m)Tc, ie, pertechnetate, there was also a species corresponding to particle-bound (99m)Tc. Gamma camera images showed substantial radioactivity over the liver and other areas of the body.


CONCLUSIONS
We conclude that inhaled (99m)Tc-labeled ultrafine carbon particles pass rapidly into the systemic circulation, and this process could account for the well-established, but poorly understood, extrapulmonary effects of air pollution.
Nemmar
A
A
Laboratory of Pneumology (Lung Toxicology, Katholieke Universiteit Leuven, Leuven, Belgium.
Hoet
P H M
PH
Vanquickenborne
B
B
Dinsdale
D
D
Thomeer
M
M
Hoylaerts
M F
MF
Vanbilloen
H
H
Mortelmans
L
L
Nemery
B
B
D000328:Adult; D000393:Air Pollutants / Q000097:blood; D006801:Humans; D019570:Inhalation Exposure; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals / Q000008:administration & dosage / Q000097:blood*; D013670:Sodium Pertechnetate Tc 99m / Q000008:administration & dosage / Q000097:blood*; D014018:Tissue Distribution
D000393:Air Pollutants; D019275:Radiopharmaceuticals; C056708:Technegas; D013670:Sodium Pertechnetate Tc 99m