Effect of electric field on erythrocyte sedimentation rate. IV. Volume fraction dependence of human red cells in plasma.
We measured the volume fraction dependence of erythrocyte sedimentation for human red cells in autologous plasma while the volume fraction, Hct, ranges from 0.220 to 0.650. A modified electrophoretic instrument was employed to investigate the electric effect of an upward DC field on erythrocyte sedimentation at a constant source supply of Vs = 60.0 +/- 0.5 V. The sedimentation curves all coincided well with the sigmoidal type equation, l = lmax/¿l + (t50/t)n¿, at Vs = 0, or 60.0 V. Here, lmax is the length of plasma level, l, when the time, t, tends to infinity; t50 is the elapsed time when the plasma level falls to lmax/2, and n is a constant (n > 0). A non-linear least-squares method was employed to fit experimental data. It was found that lmax decreased and t50 increased with the increase of Hct, while n ranged from 1.53 to 3.95. The volume fraction dependence of sedimentation velocity, Vmax, defined as the maximum slope of the sedimentation curve, fits well with an exponential-type curve, both at Vs = 60.0 V and at Vs = 0 V: Vmax = Vs (1-Hct)exp(-BHct), where Vs is the velocity at infinite dilution and B is a phenomenological parameter. In the range of Hct = 0.220-0.650, Vs and B are 326.1 mm/hr and 4.30, respectively, at Vs = 60.0 V, while they are 130.4 mm/hr and 2.46, respectively, at Vs = 0 V.
Long
M
M
Bioengineering Center, Chongqing University, Sichuan, P.R. China.
Wang
H B
HB
Wu
Z Z
ZZ
Wu
Y P
YP
Sakanishi
A
A
D001799:Blood Sedimentation; D004560:Electricity; D004911:Erythrocyte Volume / Q000502:physiology*; D006400:Hematocrit; D018056:Hemorheology; D006801:Humans; D066298:In Vitro Techniques; D008955:Models, Cardiovascular; D010949:Plasma / Q000502:physiology