{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,13]],"date-time":"2026-03-13T14:57:11Z","timestamp":1773413831519,"version":"3.50.1"},"reference-count":35,"publisher":"Wiley","issue":"5","license":[{"start":{"date-parts":[[1994,9,1]],"date-time":"1994-09-01T00:00:00Z","timestamp":778377600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J Parenter Enteral Nutr"],"published-print":{"date-parts":[[1994,9]]},"abstract":"<jats:p>Tyrosine and cyst(e)ine are amino acids that are thought to be essential for preterm neonates. These amino acids have low stability (cyst(e)ine) or low solubility (tyrosine) and are therefore usually present only in small amounts in amino acid solutions. Acetylation improves the stability and solubility of amino acids, facilitating a higher concentration in the solution. We compared three commercially available amino acid solutions, Aminoven\u00f6s\u2010N\u2010p\u00e4d 10%, Vaminolact 6.5%, and Prim\u00e8ne 10%, administered to 20 low\u2010birth\u2010weight neonates on total parenteral nutrition from postnatal day 2 onward. Aminoven\u00f6s\u2010N\u2010p\u00e4d 10% contains acetylated tyrosine and acetylated cysteine; the other solutions do not contain acetylated amino acids and differ in the amount of tyrosine and cysteine added. On postnatal day 7, plasma amino acids were measured together with urinary excretion of amino acids and the total nitrogen excretion; 38% of the intake of <jats:italic>N<\/jats:italic>\u2010acetyl\u2010L\u2010tyrosine and 53% of the intake of <jats:italic>N<\/jats:italic>\u2010acetyl\u2010L\u2010cysteine were excreted in urine. Plasma levels of <jats:italic>N<\/jats:italic>\u2010acetyl\u2010L\u2010tyrosine (331 \u00b1 74 \u03bcmol\/L) and <jats:italic>N<\/jats:italic>\u2010acetyl\u2010L\u2010cysteine (18 \u00b1 29 \u03bcmol\/L) were higher than those of tyrosine (105 \u00b1 108 \u03bcmol\/L) and cystine (11 \u00b1 9 \u03bcmol\/L), respectively. Plasma tyrosine levels in the groups receiving small amounts of tyrosine remained just below the reference range. We showed a linear correlation of plasma cystine with the intake of cysteine (<jats:italic>r<\/jats:italic> =.75, <jats:italic>p<\/jats:italic> = 0.01), but not with <jats:italic>N<\/jats:italic>\u2010acetyl\u2010L\u2010cysteine. The estimated intake of cysteine should be 500 \u03bcmol\u00b7kg<jats:sup>\u22121<\/jats:sup>\u00b7d<jats:sup>\u22121<\/jats:sup> in order to obtain levels comparable with those shown in normal term, breast\u2010fed neonates. Nitrogen retention did not differ among the three groups (247 to 273 mg\u00b7kg<jats:sup>\u22121<\/jats:sup>\u00b7d<jats:sup>\u22121<\/jats:sup>). We conclude that a large portion of parenterally administered acetylated amino acids is excreted in the urine of 1\u2010week\u2010old, preterm neonates, with higher plasma levels of the acetylated amino acids than of the deacetylated amino acids. <jats:italic>(Journal of Parenteral and Enteral Nutrition<\/jats:italic> <jats:bold>18:<\/jats:bold>404\u2013408, 1994)<\/jats:p>","DOI":"10.1177\/0148607194018005404","type":"journal-article","created":{"date-parts":[[2008,5,14]],"date-time":"2008-05-14T19:51:26Z","timestamp":1210794686000},"page":"404-408","source":"Crossref","is-referenced-by-count":60,"title":["Amino Acid Solutions for Premature Neonates During the First Week of Life: The Role of N\u2010Acetyl\u2010L\u2010Cysteine and N\u2010Acetyl\u2010L\u2010Tyrosine"],"prefix":"10.1002","volume":"18","author":[{"given":"J.B.","family":"Van Goudoever","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"E.J.","family":"Sulkers","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M.","family":"Timmerman","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"J.G.M.","family":"Huijmans","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"K.","family":"Langer","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"V.P.","family":"Carnielli","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"P.J.J.","family":"Sauer","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[1994,9]]},"reference":[{"key":"e_1_2_1_2_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1651-2227.1988.tb10778.x"},{"key":"e_1_2_1_3_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0031-3955(16)34252-3"},{"key":"e_1_2_1_4_1","first-page":"553","article-title":"Feeding 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