Phagolysosomal pH in alveolar macrophages.

Abstract

VW tdi phagolysm pH in veobr macrophags (AM) using fluorescein-labeledyead (FYP) amn silica particles (FSP) as probes. Fluorescence intensities from the ingested test particles were measured on populations of AM using fluorescence spectometry and on individual phagolysosomes using fluorescence microscopy. Measurements were performed on rabbit AM, which had been incubated with FYPorFSP (in vitot procedure). ealso insd FYPor FSP via the trachea into rabbit lungs and after 1 day, 1 week, 1 month, and 3 months lavaged thelungs and measured the pH in AM (in vivo procedure). Phagolysosomal pH was independent of the number and size of the fluorescent particles. Measurementsof uadons of AM with fluorescence spec y and of hd ual phagolysosomes with fluorescence microscopy gave similar average pH. For the FYP, pH decreased during the first day after lavage both in the in vit and the in vivo procedures. For the FSP, pH was unchaneddurngthe same period. After 1 daypH was sinilar for both particles. Electron microscopy showed a larger number of lysosomes in contact with phagosomes and a higher pementage ofvacuolated phagosomesforFYPthanforFSP. Inthein uwoprocedure, pH was unchanged at least upto 1 month, and this pH was lower than that in the in vitrv procedure. The difference was probably due to conditions at the time of phagocyosis Particles retained in the lung parenchyma were within AM, and their location within the AM appeared unchanged from 1 week up to 3 months.

NiO and Co3O4nanoparticles induce lung DTH-like responses and alveolar lipoproteinosis

“…All NPs showed minimal solubility in physiological saline and basic artificial interstitial fluid (pH 7.4), which mimics pulmonary interstitial fluid [15], while NPs showed a heterogeneous range of solubilities under acidic conditions (pH 5.5), which mimic the lysosomal environment of alveolar macrophages [14,22]. In this acid environment, CuO NPs were completely dissolved within 24 h, while other NPs showed a slow and continuous dissolution pattern in the order NiO.Co 3 O 4 .Cr 2 O 3 .…”

Interlaboratory studies on in vitro test methods for estimating in vivo resorption of calcium phosphate ceramics

“…A dissolution test is potentially a chemical alternative to animal testing for the evaluation of resorption because the resorption of calcium 5 phosphate is substantially a process of cell-mediated dissolution in acidic fluids inside the resorption lacunae underneath osteoclasts or in the phagolysosome of phagocytic cells. The values of the acidic pH have been reported to be 3.9-6.0 [19][20][21][22][23].…”

Free radical activity of PM10: iron-mediated generation of hydroxyl radicals.

“…In this paper we suggest that, as in findings with other particles, free radicals may arise from Fenton chemistry involving iron present on the particles (9-11). Additionally, we investigated whether iron could be leached from PM1o particles to a greater degree at the acid pH found in the phagolysosome (12).…”