1 Boston, Mass.
Schlitt and Keitel report (Pediatrics, 26: 249, 1960) complete reversibility of hyposthenuria in a 6-month-old subject with sickle cell disease following transfusion over a 4-day period of 290 ml of blood with a rise in maximal urine osmolality from 700 to 1100 mosmol/l. They cite this as evidence against an independent genetic defect being causal in the etiology of hyposthenuria in sickle cell disease.
It is well known that the concentrating capacity of the normal kidney increases as the ratio of urea to other solutes in the urine approaches 0.35, and the approximate range of improvement may be from 650 to 1100 mosmol/l.1