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A DEVELOPMENT OF THE LANDIS TECHNIQUE FOR MEASURING THE FILTRATION COEFFICIENT OF INDIVIDUAL CAPILLARIES IN THE FROG MESENTERY
Author(s) -
Michel C. C.,
Mason J. C.,
Curry F. E.,
Tooke J. E.,
Hunter P. J.
Publication year - 1974
Publication title -
quarterly journal of experimental physiology and cognate medical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0033-5541
DOI - 10.1113/expphysiol.1974.sp002275
Subject(s) - capillary action , filtration (mathematics) , pipette , chemistry , chromatography , hydrostatic pressure , constant (computer programming) , capillary pressure , analytical chemistry (journal) , mechanics , materials science , composite material , mathematics , porous medium , physics , porosity , statistics , computer science , programming language , organic chemistry
Two methods are described for measuring the filtration coefficient of individually perfused frog mesenteric capillaries. Both methods involve the perfusion of capillaries via a micropipette with a solution in which a small number of human red cells are suspended. After a short period of perfusion, the capillary is occluded at a point some 500 µm or more downstream from the point of cannulation. Movements of the red cells in the isolated capillary micropipette system are interpreted to be the consequence of fluid movements across the capillary wall. The filtration coefficient of the capillary is determined either (method I) from a series of different filtration rates measured at different capillary hydrostatic pressures when intracapillary colloid osmotic pressure is constant, or (method II) from the changes in filtration rate as the fluid within the capillary concentrates at a constant pressure. Values for the filtration coefficient obtained by both methods have a skewed distribution. Determinations made by method I at 14–16°C have a peak value of 2 x 10 –3 µm.sec –1 .cm H2O –1 and determinations made by method II at 22–26°C have a peak value of 5 x 10 –3 µm.sec –1 .cm H2O –1 . The assumptions underlying both methods are discussed and a mathematical model of the change in protein concentration in a closed off capillary at constant pressure is presented in the appendix.