Fig. 3. Sickle cell fraction as a function of saline pH for red blood cell (RBC)
suspensions incubated under humidified nitrogen (blue;
PO2 
0 kPa; N=4), air (black;
PO2 20.8 kPa; N=4) or oxygen
(red; PO2 100 kPa; N=3) for 45
min. The filled symbols represent individual data points. Curves are fitted
using the mean pKapp and nH values
obtained from individual animals (see Materials and methods and
Table 1). The open symbols
represent means ± s.d. for pKapp values determined
from individual curve fits. In some cases at high and low sickle cell
fraction, points are covered by overlaying symbols. See Results for references
to in vivo blood pH values as indicated below the
x-axis.