Alveolar Microenvironment and Its Relationship to the Retention and Transport Into Blood of Aerosols Deposited in the Alveoli

Intracellular Particle Dissolution in Alveolar Macrophages

“…Each particle will be enclosed within a membrane-bound phagosomal vacuole onto which lysosomes will subsequently fuse to form secondary lysosomes or phagolysosomes. As a result, the phagolysosomes will contain proteolytic enzymes, oxygen radicals, chelators, precipitators, and, at a pH of about 5 (20), all may react with the enclosed particles.…”

“…Because there are chelating agents present in the phagolysosomes of AM (20) and the pH value is in the (4) 0.8b 0.33 ± 0.07 (2) 0.37 ± 0.08 (2) 0.49 ± 0.05 (2) 0.7…”

“…It was concluded that particles that were soluble in simulants of the lining fluid in vitro would dissolve in the epithelial lining fluid (ELF) and that this dissolved material would subsequently be transferred to blood (17)(18)(19)(20); i.e., they wvuld have been cleared by the mechanism oftranslocation. This was observed for soluble aerosol particles and was determined quantitatively for a number of soluble radioactive aerosols deposited in various experimental animals (14)(15)(16)(17)(18)(19)(20)(21)(22). This approach has also been applied to less soluble particles.…”

“…This approach has also been applied to less soluble particles. Reasonable agreement was obtained when translocation in vivo was compared to dissolution of insoluble particles in lung fluid simulants (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28). It has to be stated, however, that the particles used were not uniform and that their physical parameters, in particular their specific surface areas, were not known exactly, resulting in considerable uncertainty.…”

Determination of In Vitro Lung Solubility and Intake-to-dose Conversion Factor for Tritiated Lanthanum Nickel Aluminum Alloy

“…Serum ultrafiltrate (SUF) is an aqueous solution containing various salts (2) and was used in a static dissolution system (3) to determine the dissolution rates of the material. 1.18 mg of test material was sandwiched between two 47-mm membrane filters (Tuffryn HT-200, 0.2-µm pore size, Gelman Science, Ann Arbor, MI) and secured in a Teflon filter holder (Free-Flow Filter Holder 04-112, InTox Products, Albuquerque, NM).…”