Age-specific distribution of plasma amino acid concentrations in a healthy pediatric population

Abstract

Reference values were determined for 23 plasma free amino acids from measurements done in 148 healthy children ranging from 0 to 18 years of age. Amino acid analysis was performed by ion-exchange chromatography. We propose a graphic form of presenting the age-specific distribution of plasma amino acid concentrations where the 10th, 50th, and 90th quantiles are illustrated. Although each amino acid possesses its own pattern of distribution, we can identify five different profiles. Nine amino acids (alanine, arginine, asparagine, methionine, ornithine, phenylalanine, proline, threonine, and tyrosine) demonstrate a decrease in their concentrations during the first year of life; their concentrations then tend to increase throughout childhood and adolescence. Nine others (cystine, glutamine, glycine, histidine, isoleucine, leucine, lysine, tryptophan, and valine) show a steady increase throughout infancy, childhood, and adolescence. Five amino acids (aspartic acid, citrulline, glutamic acid, serine, and taurine) do not follow these two common profiles. For the first time, quantile curves are produced to illustrate the age-dependent variation of amino acid concentrations from infancy to adulthood. This alternative way of presenting amino acid concentrations may facilitate the follow-up of patients with inborn errors of amino acid metabolism.

Kinetic and Cross-Sectional Studies on the Genesis of Hypoargininemia in Severe Pediatric Plasmodium falciparum Malaria

“…While one observational study found glutamine levels to be in the normal range among Gabonese children with severe malaria (30), low blood glutamine levels have been described in Ghanaian children with severe malaria (31) and Malawian children with cerebral malaria (32). Similar to the findings of these two studies, we observed that the plasma glutamine concentration not only was signifi- cantly lower in CM than in Tanzanian UM and HC but also was lower than established reference ranges for children (33,34). As highlighted in the first study of plasma glutamine in severe malaria (31), a low glutamine level is noteworthy in the context of human malaria, in which an impaired intestinal barrier function has been demonstrated (35,36) and is a key predisposing factor for malaria-associated nontyphoidal Salmonella bacteremia (37)(38)(39).…”

Extraction and quantification of amino acids in human stratum corneum in vivo

“…Iontophoresis was well tolerated by all subjects. As observed before, 20,24,27,33–35 only minor tingling sensations, more noticeable at the anode, were reported during the first 30 min of the experiment. The iontophoretic sites were slightly erythematous after the experiment, a situation that resolved within 24 h after termination of current.…”

Homocysteine‐betaine interactions in a murine model of 5,10‐methylenetetrahydrofolate reductase deficiency

“…Total homocysteine and total cysteine concentrations were measured after a reduction of a plasma sample by HPLC as described previously (27). Plasma amino acid concentrations were measured by HPLC, using a previously described method (28). Betaine and DMG concentrations in plasma were analyzed with HPLC as previously reported (29).…”