Table 1.

Reticulocyte CHCM (g/L) determined on fresh blood, after swelling and subsequent volume reduction (VR) in sickle and normal cells

	Fresh reticulocytes, before nystatin treatment	Swollen reticulocytes, after nystatin treatment	After VR in HBS 7.4, no urea	After VR in HBS 7.4 plus 600 mM urea	P, paired t test, no urea vs urea
SS	335 (10)*	250 (20)†	315 (07)†	38.9 (21)†	< .001
AA	308 (17)‡	244 (18)§	275 (08)§	33.8 (22)§	< .001
P, unpaired t test, SS vs AA	< .01	NS	< .001	< .001

Reticulocyte CHCM was measured in fresh blood within 4 hours of drawing into EDTA tubes. After washing in isotonic HBS, cells were treated with nystatin, washed as described in “Materials and methods,” under “Nystatin treatment,” and resuspended at 0.20 hematocrit in HBS 7.4. Samples were reserved on ice for measurement of initial CHCM (swollen reticulocytes) and then diluted to 0.02 hematocrit in 37°C buffer, either HBS 7.4 (control) or HBS 7.4 plus 600 mM urea. After 2 hours of incubation, samples were transferred to cold HBS 7.4, washed, and resuspended for Advia 120 analysis. Data shown are mean, with SEM shown in parentheses.

^*n = 6.

^†n = 12.

^‡n = 7.

^§n = 13.