THE PLASMA AMINO-ACID PROFILE AND ITS RELATIONSHIPS TO STANDARD QUANTITIES OF LIVER-FUNCTION IN INFANTS AND CHILDREN WITH EXTRAHEPATIC BILIARY ATRESIA AND PRETERMINAL LIVER-CIRRHOSIS

The absolute and relative concentrations of 16 plasma amino acids in 4 8 mostly dystrophic infants and children (median of age 1 1/2 years) w ith extrahepatic biliary atresia and mainly stable preterminal cirrhos is were compared with those of controls. Patient plasma amino acid dat a were analysed statistically for diagnostic usefulness and correlated with standard biochemical quantities of liver function and of liver p erfusion. In the patients the total amounts of non-essential and essen tial amino acids were reduced by 19%, and with the same significance ( p < 0.0005). Plasma tyrosine was increased (+40%), while taurine (-44% ) and branched chain amino acids (+28.8% to -34.7%) were decreased. Me thionine values varied widely. In the molar fractional plasma amino ac id profile, only alanine, valine, and leucine were decreased, while th reonine, methionine, tyrosine, phenylalanine, ornithine, and serine we re increased. Discriminate function analysis showed that the plasma am ino acid data discriminated 93.8% of the patients from controls. The c oncentrations of some amino acids in plasma seemed to have been influe nced by protein-calorie deficiency in the patients. The valine/tyrosin e ratio and the Fischer index (ratio branched chain/aromatic amino aci ds) were significantly reduced in the patients versus controls (1.54 /- 0.55 vs 3.08 +/- 0.55 and 1.66 +/- 0.39 vs 3.00 +/- 0.48). A number of significant correlations (range of r: 0.37-0.59, p < 0.05, 30-48 d ata pairs) were calculated between plasma amino acid data and several standard biochemical quantities of liver function. The statistical ana lyses also showed that the Fischer index began to decrease gradually a nd linearly early in the progression of liver failure. It is concluded that plasma amino acid data can be useful in the evaluation of the pr ogression of liver failure and possibly of the nutritional status in l iver transplant candidates with biliary atresia.