title: A miniature Couette to generate shear for flow cytometry: studying real-time modulation of intracellular calcium in monocytic cells.
abstract: Extracellular hydrodynamic forces may be transmitted to the interior of cells through the alteration of integrin conformation and affinity. Integrin activation regulates leukocyte recruitment, cell activation, and transmigration. The cellular and molecular mechanisms for integrin activation are not precisely known, although intracellular calcium signaling is involved. Flow cytometry offers a versatile way to study intracellular calcium signaling in real-time. We report a novel method to generate defined shear by using a miniature Couette. Testing involved measuring shear-induced intracellular calcium signals of human monoblastoid U937 cells in suspension. The Couette was connected externally to a flow cytometer and pressurized at 6 PSI (4.1 N/m(2) ). Cells were subjected to a well-defined shear between 0 and 1,000 s(-1) and delivered continuously within 10 s to a FACScan at 1 μl/s. Intracellular calcium levels and the percentage of cells activated increased as shear increased in duration and intensity.
authors: Department of Physics, University of New Mexico Health Science Center, Albuquerque, NM 87131, USA. gzwartz@salud.unm.edu
authors: Gordon J
authors: GJ
authors: Zwartz
authors: Alexandre
authors: A
authors: Chigaev
authors: Terry D
authors: TD
authors: Foutz
authors: Bruce
authors: B
authors: Edwards
authors: Larry A
authors: LA
authors: Sklar
mesh_terms: D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D009000:Monocytes / Q000378:metabolism*; D015398:Signal Transduction; D013314:Stress, Mechanical; D020298:U937 Cells
chemical_list: D002118:Calcium