Anderson G H, Patel D G, Jeejeebhoy K N
J Clin Invest. 1974 Mar;53(3):904-12. doi: 10.1172/JCI107631.
This study was undertaken to assess the efficacy of an amino acid mixture formulated for intravenous use from estimates of requirements for essential amino acids of human adults, and from data previously derived from a study using casein hydrolysate as the amino acid source. This mixture contained 39.4% essential amino acids, with glycine, alanine, arginine, histidine, and proline selected to supply the nonessential nitrogen. Nitrogen balance and blood aminograms were measured in six adult patients with gastrointestinal disease, fed intravenously for 1 wk at each of three levels of amino acid intake, while all other nutrients were constant and adequate in relation to body weight. Four of the patients were then fed 1.0 g/kg of egg or meat protein orally for 1 wk at the end of the 3 wk study, while all nutrients other than the amino acids were fed intravenously. Average nitrogen balances of -0.8, 0.5, and 2.2 g/day were observed when the amounts of amino acids infused were 0.25, 0.5, and 1.0 g/kg, respectively. Fasting levels of threonine, glycine, cystine, methionine, isoleucine, tryptophan, and arginine, but not of the other amino acids, increased with the increment in input, although the levels were generally lower than normal. The increase in blood concentration observed during infusion was similar for each of the essential amino acids, indicating that the supply of each of the amino acids was much better balanced for utilization than casein hydrolysate. However the blood aminograms did suggest that some changes in composition of the mixture for the malnourished adult were desirable, such that the amino acid mixture resembled that needed by the normal growing child. Nitrogen balance in the four patients fed orally with high-quality protein averaged 2.0 g/day, showing that an amino acid mixture given intravenously, provided it is well-balanced, can be utilized as efficiently as protein given orally. It is concluded that the prediction of oral requirements for amino acids should be combined with observations on changes in blood aminograms during infusion over a range of amino acid input in the development of amino acid mixtures for intravenous feeding.
本研究旨在根据成人必需氨基酸需求量的估计值以及先前一项以酪蛋白水解物为氨基酸来源的研究数据，评估一种配制用于静脉注射的氨基酸混合物的功效。该混合物含有39.4%的必需氨基酸，选择甘氨酸、丙氨酸、精氨酸、组氨酸和脯氨酸来提供非必需氮。对6名患有胃肠道疾病的成年患者进行了氮平衡和血液氨基酸谱测量，在三种氨基酸摄入量水平下，每名患者静脉输注1周，同时所有其他营养素相对于体重保持恒定且充足。在为期3周的研究结束时，4名患者口服1.0 g/kg的鸡蛋或肉类蛋白，为期1周，而除氨基酸外的所有营养素均通过静脉输注。当输注的氨基酸量分别为0.25、0.5和1.0 g/kg时，观察到的平均氮平衡分别为-0.8、0.5和2.2 g/天。随着输入量的增加，苏氨酸、甘氨酸、胱氨酸、蛋氨酸、异亮氨酸、色氨酸和精氨酸的空腹水平升高，但其他氨基酸的空腹水平未升高，尽管这些水平通常低于正常水平。输注期间观察到的每种必需氨基酸的血液浓度升高相似，这表明与酪蛋白水解物相比，每种氨基酸的供应在利用方面的平衡要好得多。然而，血液氨基酸谱确实表明，对于营养不良的成年人，混合物的组成需要进行一些改变，以使氨基酸混合物类似于正常生长儿童所需的混合物。4名口服优质蛋白的患者的氮平衡平均为2.0 g/天，这表明静脉注射的氨基酸混合物，只要平衡良好，其利用效率可与口服蛋白一样高。得出的结论是，在开发用于静脉喂养的氨基酸混合物时，氨基酸口服需求量的预测应与在一系列氨基酸输入量下输注期间血液氨基酸谱变化的观察结果相结合。
