publications by David Needham.

Papers Published

1. Needham, D. and Hochmuth, R.M., A sensitive measure of surface stress in the resting neutrophil, Biophys. J. (USA), vol. 61 no. 6 (1992), pp. 1664 - 70 .
   (last updated on 2007/04/06)

   Abstract:
   The simplest parameterized model of the `passive' or `resting receptive' neutrophil views the cell as being composed of an outer cortex surrounding an essentially liquid-like highly viscous cytoplasm. This cortex has been measured to maintain a small persistent tension of ~0.035 dyn/cm (Evans and Yeung. 1989. Biophys. J. 56:151-160) and is responsible for recovering the spherical shape of the cell after large deformation. The origin of the cortical tension is at present unknown, but speculations are that it may be an active process related to the sensitivity of a given cell to external stimulation and the `passive-active' transition. In order to characterize further this feature of the neutrophil the authors have used a new micropipet manipulation method to give a sensitive measure of the surface stress as a function of the surface area dilation of the highly ruffled cellular membrane. In the experiment, a single cell is driven down a tapered pipet in a series equilibrium deformation positions

   Keywords:
   biomembranes;biorheology;blood;cellular transport and dynamics;