Studies on Carbonic Anhydrase Activity in Children

1 A short review of the literature on the enzyme earbonic anhydrase is given. Special weight has been laid on earlier clinical work. 2 An account of the author's method, which is a modification of the “boat method” of Meldrum and Roughton, is given. 3 A number of normal values for the C.a. activity in the blood of adults, children in various age groups and infants are given. It is concluded, that the activity for new‐born infants is about one third that of adults, and that the enzyme activity in infants and children increases with increasing age. 4 The enzyme activity in the blood of premature infants is shown to be only about 5–10 per cent that of adults. The activity increases slowly during the first months of life. 5 The relationships between the enzyme activity and the degree of maturity, length and weight at birth are discussed. There seems to be a good correlation between enzyme activity and maturity. 6 The clinical importance of the low enzyme activity for cyanosis and vitality in premature infants is discussed. The author has not been able to verify the finding of Stevenson, that cyanosis often is associated with low carbonic anhydrase activity. 7 A parallel relationship between the enzyme activity and the zinc content of the blood is demonstrated.