OBJECTIVETo investigate the plasma amino acid spectrum in infants more than 1-year-old with neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) in order to identify potential diagnostic markers of NICCD.

METHODSInfants less than 1 year of age who had been referred to our hospital for investigation of suspected conjugated hyperbilirubinemia between June 2003 and June 2009 were eligible for enrollment. A total of 182 infants were enrolled and divided into three groups: infants diagnosed with NICCD (n = 24), according to gene testing and/or western blotting results; infants diagnosed with biliary atresia (BA; n = 20), according to intra-operative cholangiography findings; and infants diagnosed with idiopathic neonatal intrahepatic hepatitis (INH; n = 138), according to exclusionary findings for diseases affecting the extrahepatic biliary system and no positive serology results to indicate infections with hepatitis B, C, A or E, toxoplasmosis, rubella, herpes simplex, human immunodeficiency virus-1, or syphilis. The plasma amino acid spectrum of each infant was analyzed by tandem mass spectrometry (MS/MS). The concentrations of 18 amino acids, as well as the ratio of each amino acid to total amino acids, were compared among the three groups. Selected ratios of amino acids were analyzed by receiver operating characteristic (ROC) curve analysis.

RESULTSCompared with the BA and INH groups, the NICCD group had significantly lower levels of alanine (Ala; 175.7 and 205.7 vs. 136.3 mumol/L, P = 0.0001), aspartic acid (Asp; 47.5 and 43.1 vs. 31.55 mumol/L, P = 0.0041), glutamic acid (Glu; 276.16 and 263.24 vs. 175.71 mumol/L, P = 0.0075) and tryptophan (Trp; 41.90 and 47.97 vs. 28.51 mumol/L, P = 0.0003), but significantly higher levels of methionine (Met; 28.24 and 29.35 vs. 71.40 mumol/L, P = 0.0390), tyrosine (Tyr; 55.8 and 57.02 vs. 116.81 mumol/L, P = 0.0072) and citrulline (Cit; 15.09 and 15.65 vs. 97.42 mumol/L, P = 0.0001). The ratio of each amino acid to total amino acids showed the same trends for the NICCD group. The calculated areas under the ROC curves of the ratios of Cit, Tyr, and Met to the total amino acids were 0.874 (95% CI: 0.752 - 0.996), 0.814 (95% CI: 0.706 - 0.923), and 0.705 (95% CI: 0.535 - 0.875) respectively. The calculated area under the ROC curve of the ratio of Cit to Ala was 0.893 (95% CI: 0.781 - 1.005), and when the cut-off value of the ratio of Cit to Ala was 0.14 for diagnosis of NICCD, the sensitivity and specificity were 75% and 95% respectively.

CONCLUSIONThe plasma amino acid spectrum may represent a diagnostic indicator for NICCD, particularly the ratio of Cit to Ala.

Amino Acids ; blood ; Citrullinemia ; blood ; Female ; Humans ; Infant ; Male ; Tandem Mass Spectrometry

OBJECTIVETo study the changes of excitatory amino acids (EAAs) and intracellular calcium ([Ca2+]i), and the protective effect of EAAs receptor antagonists in the tissues of rabbit lumbar spinal cord after 40-minues ischemia and 4-hours reperfusion.

METHODSThirty healthy rabbits were divided into six groups: sham-operation, 40-minues ischemia, 4-hour reperfusion, ketamine and MgSO4 treatment, ketamine treatment, and saline treatment groups. The contents of EAAs (glutamate and aspartate) and [Ca2+]i were measured.

RESULTSThe contents of glutamate and aspartate were decreased to 15.18 micromol/g+/-2.33 micromol/g and 9.99 micromol/g+/-0.69 micromol/g, respectively; 13.75 micromol/g+/-2.58 micromol/g and 6.49 micromol/g+/-1.39 micromol/g after reperfusion. In the ischemia group, the [Ca2+]i was elevated to 221.2 microg/g+/-4.27 microg/g, and elevated further to 298.3 microg/g+/-9.26 microg/g after reperfusion, being significantly higher than that of ischemia and control groups. Ketamine could obviously increase the level of glutamate and aspartate and decrease the level of [Ca2+]i during the ischemia and reperfusion injury.

CONCLUSIONSThe excitotoxicity of EAAs and the overload of calcium induced by EAAs play a harmful role in ischemia and reperfusion injury. Ketamine has an effective inhibitory effect.

Animals ; Calcium ; analysis ; Excitatory Amino Acids ; blood ; Female ; Ischemia ; blood ; Male ; Rabbits ; Random Allocation ; Receptors, Amino Acid ; antagonists & inhibitors ; Reperfusion Injury ; blood ; Spinal Cord ; blood supply

OBJECTIVETo analyze and summarize clinical manifestation of maple syrup urine disease (MSUD) of neonates.

METHODSData of two cases with neonatal MSUD and the reports of 15 cases seen in the past 15 years in China were reviewed and analyzed.

RESULTSThere was an increasing number of reports of cases with neonatal MSUD. All the 17 cases had the symptom of poor feeding between 3 h and 8 d after birth; 7 cases had family history; 14 cases showed progressive neurologic signs. Odor of maple syrup occurred in 8 cases. Blood levels of branched-chain amino acids (BCAA) significantly increased in 13 cases and 6 neonates were diagnosed using tandem mass spectrometry. Urinary levels of BCAA and metabolite elevated in 12 cases and 5 neonates were diagnosed using gas chromatography-mass spectrometry. MRI/CT demonstrated abnormal signal in 10 cases. Twelve cases died or their parents gave up treatment and one case had cerebral palsy; 4 cases were treated with BCAA-free formula milk and showed improved outcome.

CONCLUSIONNewborns with MSUD often had early appeared non-specific symptoms with poor feeding and lethargy, most cases later showed an odor resembling maple syrup and neurologic signs. For patients who were suspected of having MSUD, blood and urine concentrations of BCAA should be tested for early diagnosis. Specific MRI edema signal from brain suggests the possibility of MSUD. Early intervention and treatment after diagnosis, with compliance of parents, would improve the patient's outcome.

Amino Acids, Branched-Chain ; blood ; urine ; Humans ; Infant, Newborn ; Male ; Maple Syrup Urine Disease ; diagnosis

OBJECTIVETo explore the mechanism of postoperative fatigue syndrome(POFS) by detecting the change of central monoamine neurotransmitters in a rat model after major abdominal surgery.

METHODEighty-four rats were randomly divided into fatigue assessment groups (including model group and sham group) and experimental groups (including postoperative day 1, 3, 5, 7, and 14 recovery groups and the corresponding control groups). Postoperative fatigue was evaluated after surgery. The brains were removed thereafter to detect the levels of 5-hydroxytryptamine (5-HT), norepinephrine (NE), dopamine (DA) in the hippocampus, midbrain, hypothalamus by high performance liquid chromatography. Serum free tryptophan (f-Trp) and branched-chain amino acids (BCAA) were measured.

RESULTSThe level of 5-HT increased to the highest at postoperative day 3, but reduced rapidly to the minimum at postoperative day 5, and then gradually recovered to the preoperative level. There was significant difference of 5-HT among experimental groups (P<0.05), also between the postoperative 24 hrs group and control groups (P<0.05). f-Trp and the ratio of f-Trp/BCAA increased in the early postoperative period, reduced to minimum at postoperative day 5. f-Trp was still lower compared to the control group at postoperative day 14, while the ratio of f-Trp/BCAA and BCAA restored to control level. Both of them were significantly different among experimental groups (P<0.05), also between the experimental groups and control groups (P<0.05).

CONCLUSIONChanges of f-Trp, the ratio of f-Trp/BCAA, and central 5-HT may play an important role in the development of POFS.

Abdomen ; surgery ; Amino Acids ; analysis ; Animals ; Fatigue ; blood ; Postoperative Period ; Rats ; Serotonin ; analysis

BACKGROUND: The purpose of this study was to determine the adequate loading and maintenance doses of N-acetylcyseteine (NAC) for patients suffering from acute ROS-induced injury. METHODS: Concentrations of extra cellular NAC, cysteine (Cys), cystine (Cyst2), and methionine (Met) were measured in vitro, at which more than 50% of the intracellular ROS raised by paraquat were suppressed using Swiss 3T3 fibroblasts. An in vivo pharmacokinetic study followed on a healthy subject to determine the proper loading and maintenance doses of reduced NAC following intravenous administration of 25 mg/kg NAC. RESULTS: In vivo, NAC suppressed ROS in a dose dependant manner. 10 mM of NAC suppressed about 50% of ROS, and was comparable to 10 micro M of Cys and Met and 400 micro M of Cys2. In vitro, the elimination of half-life was achieved at 2.88+/-1.14 h for NAC and at 3.68+/-1.84 h for total NAC. The body clearances were 1.23+/-0.77 L h (-1) kg (-1) and 0.56+/-0.27 L h (-1) kg (-1) and the volumes of distribution were 3.07+/-0.10 L kg (-1) and 3.00+/-0.11 L kg (-1), respectively. The loading and maintenance NAC doses used to reach the target concentration of 10 mM, were 5010 mg. kg (-1) and 2250 mg min (-1) kg (-1), respectively. CONCLUSION: NAC provides an antioxidant effect on ROS produced by paraquat in vivo. However, in vitro, our results showed that the intravenous NAC dose could not be estimated from NAC plasma concentration or its metabolites.
Sulfur/*blood ; Reactive Oxygen Species ; Humans ; Glutathione/blood ; Amino Acids/*blood/chemistry ; Acetylcysteine/*administration & dosage/pharmacokinetics/pharmacology

BACKGROUNDData of classical inborn errors of metabolism (IEM) of amino acids, organic acids and fatty acid oxidation are largely lacking in Hong Kong, where mass spectrometry-based expanded newborn screening for IEM has not been initiated. The current study aimed to evaluate the approximate incidence, spectrum and other characteristics of classical IEM in Hong Kong, which would be important in developing an expanded newborn screening program for the local area.

METHODSThe laboratory records of plasma amino acids, plasma acylcarnitines and urine organic acids analyses from year 2005 to 2009 inclusive in three regional chemical pathology laboratories providing biochemical and genetic diagnostic services for IEM were retrospectively reviewed.

RESULTSAmong the cohort, 43 patients were diagnosed of IEM, including 30 cases (69%) of amino acidemias (predominantly citrin deficiency, hyperphenylalaninemia due to 6-pyruvoyl-tetrahydropterin synthase deficiency and tyrosinemia type I), 5 cases (12%) of organic acidemias (predominantly holocarboxylase synthetase deficiency) and 8 cases (19%) of fatty acid oxidation defects (predominantly carnitine-acylcarnitine translocase deficiency). The incidence of classical IEM in Hong Kong was roughly estimated to be at least 1 case per 4122 lives births, or 0.243 cases per 1000 live births. This incidence is similar to those reported worldwide, including the mainland of China. The estimated incidence of hyperphenylalaninemia was 1 in 29 542 live births.

CONCLUSIONSOur data indicate that it is indisputable for the introduction of expanded newborn screening program in Hong Kong. Since Hong Kong is a metropolitan city, a comprehensive expanded newborn screening program and referral system should be available to serve the neonates born in the area.

Acids ; urine ; Amino Acids ; blood ; Carnitine ; analogs & derivatives ; blood ; Hong Kong ; epidemiology ; Humans ; Infant, Newborn ; Metabolism, Inborn Errors ; blood ; diagnosis ; epidemiology ; urine ; Neonatal Screening ; methods ; Tandem Mass Spectrometry

Amino Acids ; blood ; Amino Acids, Branched-Chain ; blood ; Capsules ; Drugs, Chinese Herbal ; therapeutic use ; Female ; Hepatitis B, Chronic ; blood ; drug therapy ; Humans ; Liver Cirrhosis ; blood ; drug therapy ; Male ; Phytotherapy

OBJECTIVETo explore whether SLC25A13 gene mutation exists and what is its mutation spectrum in mainland Chinese infants with intrahepatic cholestasis and abnormal blood amino acids.

METHODSBlood amino acids were analyzed by mass chromatographic analysis in infants referred to Fudan University Children's Hospital from June 2003 to June 2007 for investigations of intrahepatic cholestasis of unknown origin. SLC25A13 gene mutations were studied in 14 children whose serum levels of citrulline and/or methionine were at least two times above the upper normal range. In patients in whom only one mutation was detected, all other exons and their neighboring sequences were then analyzed.

RESULTSEight patients with SLC25A13 gene mutations, including 2 with compound heterozygous mutation 851del4/1638ins23, one with homozygous mutation 851del4/851del4, one with compound heterozygous mutation 851del4/R184X, one with homozygous mutation IVS6+1G more than A/IVS6+1G more than A, and 3 with heterozygous mutation 851del4 were found.

CONCLUSIONSSLC25A13 gene mutations exist in Chinese infants with intrahepatic cholestasis and abnormal blood amino acids. Their mutation spectrum is different from that in Japan. 851del4 is the most common mutation in our study. IVS6+1G more than A is a mutation that has not been reported before.

Amino Acids ; blood ; Cholestasis, Intrahepatic ; blood ; genetics ; DNA Mutational Analysis ; Humans ; Infant ; Infant, Newborn ; Mitochondrial Membrane Transport Proteins ; genetics ; Mutation

OBJECTIVETo explore the influence of L-arginine supplementation on the plasma amino acid spectrum in burn patients.

METHODSTen burn patients were randomly divided into burn control (n = 5, with compound 14 amino acid injection accounting for 2% of the total caloric value), and experimental (n = 5, with intravenous injection of L-arginine which accounted for 2% of total caloric value) groups. The intake of other nutrients for these two groups of patients was the same. The nutrient regimen was begun on the 3 PBD, with one quarter of the daily supply. On 4 and 5 PBD, one half of the daily supply was given, and from 6 to 21 PBD full supplementation was given. Venous blood samples were collected on 3, 7, 14, 21 and 28 PBD for the determination of plasma levels of amino acids. Ten normal volunteers served as normal control.

RESULTSThe plasma level of citrulline in both groups was significantly lower than normal value (P < 0.05) on 3 PBD before L-arginine supplementation. There was no obvious difference in plasma levels of ornithine and arginine in the two groups on 3 PBD compared with normal value (P > 0.05). The plasma level of ornithine, citrulline and arginine in burn control group declined on 3 PBD. The plasma level of arginine in experimental group on 14, 21 and 28 PBD were 280 +/- 121 micromol/L, 223 +/- 106 micromol/L and 110 +/- 44 micromol/L, respectively, which were significantly higher than those in burn control group (124 +/- 21 micromol/L, 59 +/- 15 micromol/L, 50 +/- 26 micromol/L). The plasma level of ornithine (30 +/- 5 micromol/L) and citrulline (162 +/- 44 micromol/L) on 21 PBD in experimental group were markedly higher than those in burn control group (8 +/- 7 micromol/L, 66 +/- 4 micromol/L, P < 0.05 or 0.01). There was no difference in the plasma levels of other amino acids at all postburn time points between the two groups (P > 0.05).

CONCLUSIONThe production process of L-arginine from citrulline was accelerated after burns. The plasma levels of L-arginine, ornithine and citrulline were increased markedly after L-arginine supplementation, while that of other amino acids was not influenced. The pharmacological effects of L-arginine may be related to the promotion of ornithine cycle.

Adolescent ; Adult ; Amino Acids ; blood ; Arginine ; therapeutic use ; Burns ; blood ; drug therapy ; Female ; Humans ; Male ; Parenteral Nutrition ; Wound Healing

OBJECTIVES: Recent reports have suggested that patients treated by CAPD have a relatively increased risk of death compared to patients undergoing HD, although the cause of this discrepancy is poorly understood. Protein malnutrition is an important risk factor in ESRD. Also, amino acid concentrations, for which the physiological function differs from that of protein, may be an independent risk factor in ESRD. There is no doubt concerning the prevalence of low amino acid levels in both HD and CAPD patients. But the difference in plasma amino acid levels between these two groups has not been well defined. The purpose of this study is to compare plasma amino acid levels between patients with ESRD on HD and CAPD. METHODS: A cross sectional study of overnight fasting plasma amino acid concentrations was performed on 12 CAPD and 45 HD patients with ESRD, matched by age, sex and body mass index. The levels of individual plasma amino acid and TAA, EAA, NEAA and BCAA were compared for the HD and CAPD groups. In order to measure losses during HD and CAPD, amino acid and protein concentrations were measured from 10 dialysates obtained from 10 HD patients and 12 peritoneal dialysis solutions from 12 CAPD patients. RESULTS: All of the measured amino acid concentrations were found to be lower in the CAPD group compared to the HD group. Furthermore, the levels of TAA (2017.3 +/- 781.1 vs. 903.3 +/- 316.1 mumole/L), EAA(1201.8 +/- 492.6 vs. 567.6 +/- 223.2 mumole/L), NEAA(815.5 +/- 308.6 vs. 335.7 +/- 100.2 mumole/L); and BCAA (315.0 +/- 146.0 vs. 145.2 +/- 65.0 mumole/L), were all lower in the CAPD group than in the HD group. The protein loss was 2.0 +/- 0.2 g/L in the peritoneal dialysate but was not detectable in the hemodialysates. TAA loss over a one week period was about 61.8 +/- 13.0mmole for the HD group and 38.0 +/- 13.0 mmole for the CAPD group. CONCLUSIONS: Our results show that amino acid concentrations are lower in ESRD patients on CAPD than on HD. It seems likely that protein loss in the peritoneal dialysate is a contributing factor to lowered plasma amino acid concentrations in ESRD patients on CAPD than on HD. We believe that the lowered amino acid concentrations observed in CAPD patients may worsen the clinical outcome compared to HD patients.
Adult ; Amino Acids/blood* ; Amino Acids/analysis ; Comparative Study ; Dialysis Solutions/chemistry ; Female ; Human ; Kidney Failure, Chronic/therapy* ; Kidney Failure, Chronic/blood* ; Male ; Middle Age ; Peritoneal Dialysis, Continuous Ambulatory/adverse effects* ; Renal Dialysis*/adverse effects