title: Passage of inhaled particles into the blood circulation in humans.
abstract: 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.
authors.affiliation: Laboratory of Pneumology (Lung Toxicology, Katholieke Universiteit Leuven, Leuven, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Nemmar
authors.forename: P H M
authors.initials: PH
authors.lastname: Hoet
authors.forename: B
authors.initials: B
authors.lastname: Vanquickenborne
authors.forename: D
authors.initials: D
authors.lastname: Dinsdale
authors.forename: M
authors.initials: M
authors.lastname: Thomeer
authors.forename: M F
authors.initials: MF
authors.lastname: Hoylaerts
authors.forename: H
authors.initials: H
authors.lastname: Vanbilloen
authors.forename: L
authors.initials: L
authors.lastname: Mortelmans
authors.forename: B
authors.initials: B
authors.lastname: Nemery
mesh_terms: 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
chemical_list: D000393:Air Pollutants; D019275:Radiopharmaceuticals; C056708:Technegas; D013670:Sodium Pertechnetate Tc 99m