title: Polystyrene microspheres as a specific marker for the diagnosis of aspiration in hamsters.
abstract: The diagnosis of recurrent aspiration in young children is problematic because there is no specific gold standard test to be used. In the present work, normal saline or a suspension of white polystyrene microspheres in normal saline was instilled into hamsters' trachea (n = 42), and bronchoalveolar lavage (BAL) cytology, microsphere index (total microspheres/100 macrophages), and lung histology were followed for 90 d. Naive animals (n = 6) had no tracheal instillation. On Days 1, 3, 10, 32, 60, and 90 after tracheal instillation, animals were killed (saline-instilled animals, n = 3; and microsphere-instilled animals, n = 4), and BAL was performed. There was a marked inflammatory response in BAL on Day 1 after tracheal instillation of saline or microsphere suspension. White microspheres were clearly identified within alveolar macrophages in all studied days. Microsphere numbers showed a 50% disappearance rate of 10 d. A mild peribronchial inflammation was noted in lung histology only on Day 1 after instillation. Microspheres were not detected in extrapulmonary organs. We conclude that polystyrene microspheres instilled in hamsters' trachea can be easily identified in BAL macrophages for as long as 3 mo and could potentially be used as a sensitive, specific, and stable marker for the diagnosis of aspiration.
mesh_terms: D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D006224:Cricetinae; D005260:Female; D001239:Inhalation; D008168:Lung / Q000473:pathology; D008647:Mesocricetus; D008863:Microspheres; D009504:Neutrophils / Q000166:cytology; D011015:Pneumonia, Aspiration / Q000175:diagnosis*; D011137:Polystyrenes / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D013997:Time Factors; D014132:Trachea / Q000378:metabolism
chemical_list: D011137:Polystyrenes; D012965:Sodium Chloride