title: Effect of electric field on erythrocyte sedimentation rate. IV. Volume fraction dependence of human red cells in plasma.
abstract: 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.
authors.affiliation: Bioengineering Center, Chongqing University, Sichuan, P.R. China.
authors.forename: M
authors.initials: M
authors.lastname: Long
authors.forename: H B
authors.initials: HB
authors.lastname: Wang
authors.forename: Z Z
authors.initials: ZZ
authors.lastname: Wu
authors.forename: Y P
authors.initials: YP
authors.lastname: Wu
authors.forename: A
authors.initials: A
authors.lastname: Sakanishi
mesh_terms: 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