Rudman D, Kutner M, Ansley J, Jansen R, Chipponi J, Bain R P
Gastroenterology. 1981 Dec;81(6):1025-35.
Six patients with gastrointestinal malabsorption and 12 with alcoholic cirrhosis received total parenteral nutrition for 4 wk. Freamine II, the source of the amino acids, is nearly devoid of cystine and tyrosine. We monitored daily nitrogen balance and other nutritional parameters and 22 plasma amino acids. Malabsorbers had a strongly positive nitrogen balance and improvements in nutritional parameters. Plasma amino acids were maintained within or above their normal fasting ranges. Eight of 12 cirrhotics resembled malabsorbing patients in terms of positive nitrogen balance, improved nutritional parameters, and plasma amino acids. In 4 cirrhotics, nitrogen balance remained negative and nutritional repletion failed to occur. Plasma cystine and tyrosine fell to below 30% of their normal fasting means. In 2 of these patients, oral supplements of cystine and tyrosine were given during the fifth week of parenteral nutrition. Plasma cystine and tyrosine were normalized, nitrogen balance became positive, and other repletion indicators demonstrated recovery. We conclude that in 4 cirrhotics, repletion was blocked by deficiencies of cystine and tyrosine, resulting from hepatic inability to synthesize cystine from methionine and tyrosine from phenylalanine.
6例胃肠道吸收不良患者和12例酒精性肝硬化患者接受了为期4周的全胃肠外营养。氨基酸来源为Freamine II，几乎不含胱氨酸和酪氨酸。我们监测了每日氮平衡及其他营养参数和22种血浆氨基酸。吸收不良患者氮平衡呈强阳性，营养参数有所改善。血浆氨基酸维持在正常空腹范围之内或之上。12例肝硬化患者中有8例在氮平衡呈阳性、营养参数改善及血浆氨基酸方面与吸收不良患者相似。4例肝硬化患者氮平衡仍为阴性，营养补充未成功。血浆胱氨酸和酪氨酸降至正常空腹均值的30%以下。在其中2例患者中，在胃肠外营养的第5周给予了胱氨酸和酪氨酸口服补充剂。血浆胱氨酸和酪氨酸恢复正常，氮平衡转为阳性，其他补充指标显示恢复。我们得出结论，在4例肝硬化患者中，由于肝脏无法从蛋氨酸合成胱氨酸以及从苯丙氨酸合成酪氨酸，胱氨酸和酪氨酸缺乏阻碍了营养补充。
