| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Biophysical Journal 72: 214-222 (1997)
© 1997 the Biophysical Society
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge 02139, USA.
ABSTRACT
The filtration rates for water and a polydisperse mixture of Ficoll across films of isolated glomerular basement membrane (GBM) were measured to characterize convective transport across this part of the glomerular capillary wall. Glomeruli were isolated from rat kidneys and the cells were removed by detergent lysis, leaving a preparation containing almost pure GBM that could be consolidated into a layer at the base of a small ultrafiltration cell. A Ficoll mixture with Stokes-Einstein radii ranging from about 2.0 to 7.0 nm was labeled with fluorescein, providing a set of rigid, spherical test macromolecules with little molecular charge. Filtration experiments were performed at two physiologically relevant hydraulic pressure differences (delta P), 35 and 60 mmHg. The sieving coefficient (filtrate-to-retentate concentration ratio) for a given size of Ficoll tended to be larger at 35 than at 60 mmHg, the changes being greater for the smaller molecules. The Darcy permeability also varied inversely with pressure, averaging 1.48 +/- 0.10 nm2 at 35 mmHg and 0.82 +/- 0.07 nm2 at 60 mmHg. Both effects could be explained most simply by postulating that the intrinsic permeability properties of the GBM change in response to compression. The sieving data were consistent with linear declines in the hindrance factors for convection and diffusion with increasing pressure, and correlations were derived to relate those hindrance factors to molecular size and delta P. Comparisons with previous Ficoll sieving data for rats in vivo suggest that the GBM is less size-restrictive than the cell layers, but that its contribution to the overall size selectivity of the barrier is not negligible. Theoretical predictions of the Darcy permeability based on a model in which the GBM is a random fibrous network consisting of two populations of fibers were in excellent agreement with the present data and with ultrastructural observations in the literature.
This article has been cited by other articles:
 |
|
 |
|
  K. J. Mattern, C. Nakornchai, and W. M. Deen Darcy Permeability of Agarose-Glycosaminoglycan Gels Analyzed Using Fiber-Mixture and Donnan Models Biophys. J., July 15, 2008; 95(2): 648 - 656. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. Haraldsson, J. Nystrom, and W. M. Deen Properties of the Glomerular Barrier and Mechanisms of Proteinuria Physiol Rev, April 1, 2008; 88(2): 451 - 487. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. L. Hunt, M. R. Pollak, and B. M. Denker Cultured Podocytes Establish a Size-Selective Barrier Regulated by Specific Signaling Pathways and Demonstrate Synchronized Barrier Assembly in a Calcium Switch Model of Junction Formation J. Am. Soc. Nephrol., June 1, 2005; 16(6): 1593 - 1602. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. B. Kosto and W. M. Deen Hindered Convection of Macromolecules in Hydrogels Biophys. J., January 1, 2005; 88(1): 277 - 286. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. M. Deen, M. J. Lazzara, and B. D. Myers Structural determinants of glomerular permeability Am J Physiol Renal Physiol, October 1, 2001; 281(4): F579 - F596. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Edwards, B. S. Daniels, and W. M. Deen Ultrastructural model for size selectivity in glomerular filtration Am J Physiol Renal Physiol, June 1, 1999; 276(6): F892 - F902. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. R. Bolton, W. M. Deen, and B. S. Daniels Assessment of the charge selectivity of glomerular basement membrane using Ficoll sulfate Am J Physiol Renal Physiol, May 1, 1998; 274(5): F889 - F896. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
