Pulmonary macrophages defend the respiratory surfaces of the lungs against deposited particles through their phagoctic and migratory capabilities. a novel method, involving microscopic magnetic particles, promises to be a valuable expermental indicator of macrophage function, by providing information noninvasively on the motions of cell organelles. When humans or animals inhale a magnetic-particle aerosol, a fraction of the particles are retained in the lungs and ingested by pulmonary macrophages. We have found that for phagocytized particles, cytoplasmic motions rotate the particles and produce detectable changes in the magnetic field. Thus, sensitive magnetometry may serve as an experimental probe of the motile status of macrophages, specifically, a probe not rrequiring optical observation of cells on the stage of a microscope. In addition, intracellular particles can be twisted by an applied external field, which allows measurement of cytosol viscoelasticity. The proposed research will examine magnetometric phenomena for lung macrophages in culture. We week to answer the following question: (1) How do magnetometric signals correlate to optically-observed cell organelle motions? (2) How do magnetometrically-measured motion and viscoelasticity change with macrophage functional status and cytoskeletal integrity? (3) Can intracellular magnetic particle motions be used to help formulate and test models of intracellular force generation and viscoelasticity? The goal is to critically examine magnetometry as a non-optical method for probing cellular motile proceses. Magnetometry may provide a unique diagnostic procedure for in situ assessment of the behavior of phagocvytic cells.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL036427-02
Application #
3351461
Study Section
(SSS)
Project Start
1988-08-01
Project End
1991-07-31
Budget Start
1989-08-01
Budget End
1990-07-31
Support Year
2
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Harvard University
Department
Type
Schools of Public Health
DUNS #
082359691
City
Boston
State
MA
Country
United States
Zip Code
02115
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Bizal, C L; Butler, J P; Valberg, P A (1991) Viscoelastic and motile properties of hamster lung and peritoneal macrophages. J Leukoc Biol 50:240-51
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