title: Magnetic semipermeable aqueous polyethyleneimine microcapsules for monitoring N-nitrosating species in the gastrointestinal tract.
abstract: Magnetic polyethyleneimine (PEI) microcapsules have been developed for trapping electrophilic intermediates in the gastrointestinal (GI) tract. The N-nitrosation of these microcapsules at acid pH was found to be linearly dependent on nitrite concentration, without a pH maximum and with efficient conversion to N-nitrosated products which were detected by a total N-nitroso assay procedure. The limit of detection is in the range 1-10 nmol N-nitroso compound, depending on microcapsule preparation conditions. Nuclear magnetic resonance (NMR) indicates that such N-nitrosation is favoured by incomplete protonation of the polyamine. Microcapsules administered orally to rats were recovered magnetically from faeces and showed extensive N-nitrosation when nitrite was administered in the drinking-water.
authors: International Agency for Research on Cancer, Lyon, France.
authors: I K
authors: IK
authors: O'Neill
authors: M
authors: M
authors: Castegnaro
authors: I
authors: I
authors: Brouet
authors: A C
authors: AC
authors: Povey
mesh_terms: D004064:Digestive System / Q000378:metabolism*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008280:Magnetics; D008863:Microspheres; D009573:Nitrites / Q000378:metabolism; D011094:Polyethyleneimine / Q000378:metabolism*; D011095:Polyethylenes / Q000378:metabolism*
chemical_list: D009573:Nitrites; D011095:Polyethylenes; D011094:Polyethyleneimine