Self Diffusion in Cells and Tissues.
Annual rept. no. 2, 1 Jul 75-30 Sep 76,
NAVAL WEAPONS SUPPORT CENTER CRANE IND
Pagination or Media Count:
The self diffusion coefficient of water has been measured in packed cell samples of human red cells, Escherichia coli, and yeast over a very large range of diffusion times, from 0.3 msec to 1.0 sec. The value at the shortest times is equal or nearly equal to the true cytoplasmic diffusion coefficient. This is a factor of three lower than the value previously reported for three different types of frog muscle, and is taken as an indication of greater obstruction by intracellular membranes and other structures. Measurements of spin relaxation show that reorientation and diffusion of the major portion of the cell water are slowed by about the same amount compared to pure water. From the diffusion coefficient at longer times, the permeabilities of the outer membranes are estimated to be 0.02 cmsec for two of the frog muscles and for the red cells, and much higher for the other frog muscle and for the E. coli cells.
- Anatomy and Physiology