Mechanisms Underlying the "Particle Redistribution Phenomenon"

Lehnert, Bruce E.; Ortiz, Jeanelle B.; Steinkamp, John A.; Tietjen, Gary L.; Sebring, R. J.; Oberdörster, Günter

doi:10.1089/jam.1992.5.261

Cited by 11 publications

(3 citation statements)

References 21 publications

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“…A third, and perhaps most probable, explanation might be that particles released by cells in the higher burden categories are rephagocytized by other cells, resulting in "redistribution" of particles from one cell to another. The possible mechanisms underlying cell-to-cell particle redistribution have previously been discussed in detail elsewhere (30). The cells that phagocytize the released particles are most likely to be cells that previously did not contain particles, because, proportionally, they are much more abundant than particle-laden AMs.…”

Section: Discussionmentioning

confidence: 99%

Retention and Intracellular Distribution of Instilled Iron Oxide Particles in Human Alveolar Macrophages

Lay

Bennett

Kim

et al. 1998

Am J Respir Cell Mol Biol

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Bronchoalveolar lavage (BAL) was used to sample retention of particles within the alveolar macrophage (AM) compartment at various times from 1 to 91 d following intrapulmonary instillation of 2. 6-microm-diameter iron oxide (Fe2O3) particles in human subjects. Particles were cleared from the lavagable AM compartment in a biphasic pattern, with a rapid-phase clearance half-time of 0.5 d and long-term clearance half-time of 110 d, comparable to retention kinetics determined by more traditional methods. The intracellular distribution of particles within lavaged AMs was similar in bronchial and alveolar BAL fractions. AMs with high intracellular particle burdens disappeared from the lavagable phagocytic AM population disproportionately more rapidly (shorter clearance half-time) than did AMs with lower particle burdens, consistent with the occurrence of a particle redistribution phenomenon as previously described in similar studies in rats. The rates of AM disappearance from the various particle burden categories was generally slightly slower in bronchial fractions than in alveolar fractions. The instillation of particles induced a transient acute inflammatory response at 24 h postinstillation (PI), characterized by increased numbers of neutrophils and alveolar macrophages in BAL fluids. This response was subclinical and was resolved within 4 d PI.

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Section: Discussionmentioning

confidence: 99%

Retention and Intracellular Distribution of Instilled Iron Oxide Particles in Human Alveolar Macrophages

Lay

Bennett

Kim

et al. 1998

Am J Respir Cell Mol Biol

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“…As they approach the end of their life cycle, AMs become inactive and, upon death, their particle loads are released back onto the alveolar surface to be rephagocytosed by healthier AMs. This is known as the particle redistribution phenomenon (Lehnert et al, 1992). The process is likely to be accelerated when the macrophages are loaded with particles.…”

Section: Removal Of Particles From the Lungmentioning

confidence: 99%

“…The proximity of the macrophages to these cells means that any mediators released by the IM can have maximal impact. These interstitialized particles, either free or phagocytosed, may eventually be transported to the lymph nodes (Lehnert et al, 1992). Current evidence suggests that the transportation of inhaled particles to the lymph nodes is also size dependent (Oberdörster et al, 1988).…”

Section: Removal Of Particles From the Lungmentioning

confidence: 99%

Mathematical Modeling of the Retention and Clearance of Low-Toxicity Particles in the Lung

Tran

Jones²,

Cullen³

et al. 1999

Inhalation Toxicology

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A mathematical model has been formulated to describe the mechanisms that determine the retention or clearance of insoluble inhaled particles in the rat lung. The hypotheses underlying the model are described-for example, the phagocytosis of free particles by macrophages, the transport of particles in macrophages from the alveolar region, the effect of the life cycle of macrophages leading to the eventual release of phagocytosed particles, the effect of lung burden on the macrophage activity, the transport of particles into the interstitium, the role of interstitial macrophages, the formation of granulomata, and transport of interstitialized particles to the thoracic lymph nodes. With these hypotheses, the fate of particles is described mechanistically via the cellular response of the lung. The mathematical model expresses these particle transitions as differential equations quantifying the transport of particles from one compartment to another, where the compartments represent the alveolar surface, the alveolar macrophages, overloaded alveolar macrophages, the interstitium, interstitial macrophages, and the thoracic lymph nodes. A companion article describes the application of the model to a data set from rats exposed to a low-toxicity dust at several concentrations and for a range of exposure times.

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Allgemeiner Staubgrenzwert (A‐Fraktion) (Granuläre biobeständige Stäube (GBS)) [MAK Value Documentation in German language, 2012]

2014

The MAK‐Collection for Occupational Health and Safety

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Veröffentlicht in der Reihe Gesundheitsschädliche Arbeitsstoffe , 53. Lieferung, Ausgabe 2012 Der Artikel enthält folgende Kapitel: Allgemeiner Wirkungscharakter Wirkungsmechanismus Eingrenzung der berücksichtigten experimentellen Daten sowie Limitierungen der Methodik Wirkmechanismus von biobeständigen Partikeln Einzelne Wirkungen granulärer biobeständiger Stäube Von der Entzündung zur Mutation Überladungshypothese Wirken granuläre biobeständige Stäube direkt auf Lungenepithelzellen und verursachen dadurch die maligne Entartung („direkte oder primäre Gentoxizität”) oder wirken sie durch Vermittlung der von Phagozyten abgegebenen Sauerstoffradikale („sekundäre Gentoxizität”)? Interspezies‐Vergleich / Zur Frage der unterschiedlichen Tumorlokalisationen bei Mensch und Ratte Zellbiologische Endpunkte einer unphysiologischen Belastung der Lunge mit biobeständigen granulären Stäuben Toxikokinetik Erfahrungen beim Menschen Einmalige Exposition Wiederholte Exposition Kanzerogenität Tierexperimentelle Befunde und In‐vitro‐Untersuchungen Akute Toxizität Toxizität nach wiederholter Exposition Wirkung auf Haut und Schleimhäute Allergene Wirkung Reproduktionstoxizität Genotoxizität Kanzerogenität Ableitung eines Grenzwertes für die alveolengängige Staubfraktion von granulären biobeständigen Stäuben (GBS) Bewertung

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Mechanisms Underlying the "Particle Redistribution Phenomenon"

Cited by 11 publications

References 21 publications

Retention and Intracellular Distribution of Instilled Iron Oxide Particles in Human Alveolar Macrophages

Retention and Intracellular Distribution of Instilled Iron Oxide Particles in Human Alveolar Macrophages

Mathematical Modeling of the Retention and Clearance of Low-Toxicity Particles in the Lung

Allgemeiner Staubgrenzwert (A‐Fraktion) (Granuläre biobeständige Stäube (GBS)) [MAK Value Documentation in German language, 2012]

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