Intracellular particle dissolution

Intracellular particle dissolution by alveolar macrophages (AM) and other phagocytic cells... 

Kinetics of intracellular Particle Dissolution by Alveolar Macrophages... 

Dissolution rates are potentially sensitive to conditions in the medium inside the phagolysosomal vaeuole of the AM, making it difficult to simulate intracellular particle dissolution in AM. In fact, dissolution rates in the respiratory tract could well differ according to whether the particles are in the epithelial lining fluid, or phagocytosed by AM. Lundborg et al. (140,141) were the first to... 

To better understand the tmderlying mechanisms of particle dissolution, several investigators studied particle dissolution in cultures of AM (140,141,153,154). It was confirmed by electron microscopy that particles were contained in membrane-bound vacuoles (phagosomes) onto which primary lyso-somes fused, forming phagolysosomes. To quantify the kinetics of intracellular particle dissolution, we developed a 2-week cell culture assay in which uniform, moderately soluble Co304 particles were quantitatively phagocytosed and continuously dissolved by AM. From the increase with time of the dissolved Co fractions a dissolution rate was evaluated (122,136,155-157). 

Intracellular particle dissolution rates obtained from cultured dog AM increased with increasing specific surface area of different 0304 particles, snch that the dissolution rate constant for 00364 was calculated to be = 4.1 0.5 10 g/cm per day (145). The very close agreement of the two dissolntion rate constants—given earlier and —showed that the dissolving medium... 

Harper RA, Stirling C, Townsend KMS, Kreyling WG, Patrick G. Intracellular particle dissolution in macrophages isolated from the lungs of the Fischer (F-344) rat. Exp Lung Res 1994 20 143-156. 

Kreyling WG, Beisker W, Berg I, Gercken G, Miaskowski U, Neuner M, Schliiter T, Heilmann P. Particle clearance functions of alveolar macrophages of different species intracellular particle dissolution and phagolysosomal pH. Eur Respir J 1992 4 70. 

In summary, dissolution of particles that are not readily soluble is maintained intracellularly in AM. For those particles, snch as many metal oxides, that are more soluble in more acidic aqueous solvents, particle dissolution is faster than in extracellular lung fluids owing to the phagolysosomal pH value of 4.3-5.3. For these particles, intracellular dissolution is an important clearance mechanism. It eventually turns into an essential clearance pathway out of the lungs if the dissolved particle material is not bound to a molecular partner that remains retained in some sites of the lungs, but is transported to blood vessels. 

Intracellular dissolution of a large variety of inhaled inorganic particles not readily soluble in the pulmonary epithelial lining fluid constitutes an important long-term clearance mechanism of the lungs. Fluorescence microscope photometry and dual laser flow cytometry of intraphagolysosomal pH in... 

Efficient intracellular delivery of the anticancer drug camptothecin (CPT) by hollow silica/titania nanoparticles has been reported [114]. Monodispersed hollow nanoparticles (about 50 nm) were prepared by titania coating of Stober silica particles followed by silica dissolution and redeposition in an ammonia solution (Figure 11.13). Surface modification of these particles with an antibody herceptm, a... 

Ltidtke K-U, Forderkunz S, Neuner M,Summer K-H, Kreyling WG. Mechanisms of intracellular dissolution of cobalt oxide particles by canine alveolar macrophages. Eur Respir J 1994 7 70. 

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