Bakker H D, Wadman S K, Van Sprang F J, Van der Heiden C, Ketting D, De Bree P K
Clin Chim Acta. 1975 May 15;61(1):73-90. doi: 10.1016/0009-8981(75)90399-x.
Tyrosyluria and for a part also tyrosinemia were studied in 60 healthy prematures of various birth weights and gestational ages. The first analyses were performed between the 6th and the 14th day after birth. A normal milk diet was given and the protein-intake was between 3 and 4 g/kg. After the first collection of urine half the patients received extra ascorbic acid, 100 mg/kg daily. Urinary analyses of tyrosine and p-hydroxyphenyl metabolites were performed once a week, until the excretion of p-hydroxyphenylpyruvic plus p-hydroxyphenyllactic acids was lower than 5 mmoles per gram creatinine. In 22 out of the 60 prematures (or 37%) a tyrosyluria of more than 5 mmoles/g creatinine and in 19 out of 44 (43%) patients analysed serum tyrosine was higher than 5 mg/100 ml at first analysis. No inverse correlation between tyrosyluria and tyrosinemia on the one hand and birth weight and gestational age on the other hand existed. But in children with a delayed intra-uterine development the incidence of tyrosyluria was higher as prematurity was more pronounced. Ascorbic acid had no effect on the rate of disappearance of tyrosyluria. It was concluded that the addition of extra vitamin C to the diet of prematures is not useful for the normalization of tyrosine metabolism.
对60名不同出生体重和胎龄的健康早产儿进行了酪氨酸尿症研究，部分还研究了酪氨酸血症。首次分析在出生后第6天至第14天之间进行。给予正常的奶类饮食，蛋白质摄入量为3至4克/千克。在首次收集尿液后，一半患者每天额外摄入100毫克/千克的抗坏血酸。每周进行一次酪氨酸和对羟基苯代谢物的尿液分析，直到对羟基苯丙酮酸加对羟基苯乳酸的排泄量低于每克肌酐5毫摩尔。60名早产儿中有22名（即37%）的酪氨酸尿症超过5毫摩尔/克肌酐，在44名接受分析的患者中有19名（43%）在首次分析时血清酪氨酸高于5毫克/100毫升。一方面，酪氨酸尿症和酪氨酸血症与另一方面的出生体重和胎龄之间不存在负相关。但在宫内发育延迟的儿童中，随着早产程度加重，酪氨酸尿症的发生率更高。抗坏血酸对酪氨酸尿症的消失速率没有影响。得出的结论是，在早产儿饮食中额外添加维生素C对酪氨酸代谢的正常化没有作用。
