The effect of polycythemia and hypoxia on urinary N-acetyl-beta-D-glucosaminidase activity in newborns.

Urinary N-acetyl-beta-D-glucosaminidase activity was assayed in fullterm and preterm polycythemic neonates, in preterm infants with hypoxia, and in healthy newborns. There were no significant differences between fullterm and preterm babies or between appropriate for gestational age and small for gestational age neonates in the normal group. N-acetyl-beta-D-glucosaminidase excretion on the first day of life was significantly raised in polycythemic newborns (P less than 0.01). Fourteen days after partial plasma exchange the enzyme activity returned to normal. N-acetyl-beta-D-glucosaminidase activities in preterm babies with respiratory distress syndrome were significantly (P less than 0.01) raised on the 1st, 2nd, 4th days and fell sharply to the 14th day. N-acetyl-beta-D-glucosaminidase isoenzyme studies revealed that urine samples taken from preterm babies with respiratory distress syndrome in the first week after birth contained increased amounts of intermediate and B isoenzyme forms while there was a concomitant reduction in the amount of the A form present.