title: Cell orientation induced by extracellular signals.
abstract: Cells like fibroblasts and osteoblasts are oriented by different extracellular guiding signals like an electric field, a bent surface, and a periodically stretched surface. An automatic controller is responsible for the cell alignment. The controller contains both a deterministic and a stochastic signal. The following machine properties were determined: (1) The angle dependence of the cellular signal transformer is cos 2(psi 0 - psi). (2) The set point of the automatic controller is psi 0 = +/- 90 degrees. The cells like to orient their long axis perpendicular to the direction of the applied guiding signal. (3) The signal transformer measures the extracellular signal in a quadratic fashion. The cells cannot register the sign of the guiding field. (4) The stochastic signal in the automatic controller can be quantified by a characteristic time (approximately 130 min for fibroblasts). (5) The extracellular signal is registered in cell-made standards (ratio of the deterministic and stochastic signal equals one): 0.3 +/- 0.05 V/mm for human fibroblasts (electric field) and 85 +/- 3 microns for human fibroblasts and osteoblasts (cyclindrically bent surface). (6) The lag-time in the signal transduction system of fibroblasts is approximately 4 min.
authors.affiliation: BioPhysics Department, Complex Fluids Group, Ulm, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Kemkemer
authors.forename: C
authors.initials: C
authors.lastname: Neidlinger-Wilke
authors.forename: L
authors.initials: L
authors.lastname: Claes
authors.forename: H
authors.initials: H
authors.lastname: Gruler
mesh_terms: D016764:Cell Polarity / Q000502:physiology*; D004594:Electrophysiology / Q000295:instrumentation / Q000379:methods; D005347:Fibroblasts / Q000502:physiology; D006801:Humans; D007700:Kinetics; D008962:Models, Theoretical; D010006:Osteoblasts / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D013269:Stochastic Processes; D013997:Time Factors