O perfil metabolômico de aminoácidos como biomarcador de consumo alimentar, estado nutricional e alterações metabólicas / The metabolomic profile of amino acids as biomarkers of food consumption, nutritional state and metabolic alterations

Introdução - A metabolômica permite determinar padrões de variação dos metabólitos entre indivíduos doentes e não doentes, com ou sem ingestão de um determinado alimento ou dieta. Compreender a relação entre metabólitos e doenças metabólicas pode ajudar a combater obesidade e doenças crônicas. Objetivo - Investigar a associação entre o perfil metabolômico de aminoácidos, a ingestão dietética e o estado nutricional em adultos participantes do Inquérito de Saúde no município de São Paulo, Brasil. Métodos - Foram avaliados dados de 168 indivíduos. A análise metabolômica para identificação de 21 aminoácidos foi realizada nas amostras de plasma, utilizando kit AbsoluteIDQTMp180 da Biocrates Life Science AG (Innsbruck, Austria). O consumo alimentar foi estimado por meio da aplicação do questionário de frequência alimentar. Os grupos de aminoácidos e de alimentos foram submetidos à análise fatorial por componente principal. A variável Metabolicamente Saudável foi construída considerando-se as Diretrizes da Sociedade Brasileira de Cardiologia para o diagnóstico e tratamento da síndrome metabólica. A regressão linear múltipla foi aplicada para avaliar as associações, tendo como variáveis de ajustes: etnia, idade, renda familiar, sexo, dieta, atividade física. A comparação entre grupos foi feita por MANOVA e a confirmação da diferença significativa pelo teste de Bonferroni. Resultados - A porcentagem de indivíduos com obesidade foi de 24%, sendo que a média de IMC correspondeu a 26 kg/m2. A população estudada apresentou média de idade de 50 anos, sendo a maioria de etnia branca (56%) e do sexo masculino (52%), com pouca adesão à atividade física (21%). Os parâmetros bioquímicos estavam, em média, abaixo das concentrações estabelecidas como normais, exceto a insulina, cuja média foi de 20,8 ?UI/mL. Todavia, ao estratificar pelo estado nutricional e metabolicamente saudável, os parâmetros bioquímicos se mostraram diferentes, tais como a glicemia, triglicerídeos e colesterol total. A ingestão dietética foi igual entre os grupos estudados. O perfil de aminoácido revelou potencial de diferenciar os estados nutricional e metabólico, destacando os aminoácidos de cadeia ramificada (Leu, Ile, Val). Foram identificados dois padrões de aminoácidos relacionados a beta oxidação e aos aminoácidos glicogênicos. O primeiro teve relação positiva para os indivíduos com obesidade e metabolicamente não saudável. O segundo, apresentou relação inversa para ambos os estados. O consumo de manganês pela população foi de 2,5 mg/dia, sendo infusão de mate a principal fonte (28mg Mn/porção). Os indivíduos obesos ingeriram menor quantidade de manganês, que apresentou relação inversa ao estado nutricional e ao padrão de aminoácidos relacionado ao metabolismo não saudável. Identificaram-se três padrões alimentares: perfil saudável, tradicional e moderno. A associação com o estado nutricional e metabolicamente saudável foi positiva para o padrão saudável. Conclusão - Os aminoácidos de cadeia ramificada se revelaram biomarcadores para identificar o estado nutricional e metabólico de indivíduos adultos. Os indivíduos que tiveram baixo consumo de manganês apresentaram maior adesão ao perfil metabolômico de aminoácidos relacionados com beta oxidação

Introduction - The metabolomics allows to determine patterns of variation of the metabolites between people with or without illness, considering or not the food consumption. Understanding the relationship between metabolites and metabolic disorders, it is possible to deal with obesity and chronic diseases. Objective - To investigate the association between the metabolic profile of amino acids and dietary intake and nutritional status in adults from the household survey conducted in the city of São Paulo, Brazil. Method - The 21 amino acids were identified by metabolomic analysis, using Absolute IDQTMp 180 kit from Biocrates Life Science AG (Innsbruck, Austria). Food intake was estimated using the food frequency questionnaire. The amino acid and food groups were submitted to factorial analysis by main component. The Metabolically Healthy variable was constructed considering the Guidelines of the Brazilian Society of Cardiology for the diagnosis and treatment of the metabolic syndrome. Multiple linear regression was applied to evaluate the associations, adjusted by the variables: ethnicity, age, family income, sex, diet, physical activity. The comparison between groups was made by MANOVA, and the confirmation of the significant difference, by the Bonferroni test. Results - The percentage of people with obesity was 24%, although the mean BMI corresponded to 26 kg/m2. The population studied presented a mean age of 50 years, most of them white (56%) and male (52%), with little adherence to physical activity (21%). The biochemical parameters were, on average, below the established normal concentrations, except for insulin (20,8 ?UI/mL). However, when stratified by nutritional status and metabolically healthy, the biochemical parameters were statistically different. The dietary intake was the same among the groups studied. The amino acid profile revealed potential to differentiate the nutritional and metabolic states, highlighting the branched chain amino acids. Two amino acid patterns related to beta-oxidation and glycogenic amino acids had been identified. The former had a positive relationship for obese and metabolically unhealthy people. The second presented an inverse relation for both states. The manganese consumption by the population was 2.5 mg / day, and the mate infusion was the main source (28mg Mn/serving). Obese subjects consumed less manganese, which had an inverse relationship to nutritional status and to the amino acid pattern related to unhealthy metabolism. Three dietary patterns were identified: healthy, traditional and modern profiles. The association with nutritional and metabolically healthy status was positive for the healthy pattern. Conclusion - The branched-chain amino acids had been revealed to be biomarkers to identify the nutritional and metabolic status of adult individuals. The individuals that had low manganese consumption showed greater adhesion to the metabolic profile of amino acids related to beta-oxidation, and could be used as biomarker for the ingestion of this micronutrient

Reference values of amino acids, acylcarnitines and succinylacetone by tandem mass spectrometry for use in newborn screening in southwest Colombia / Valores de referencia de aminoácidos, acilcarnitinas y succinilacetona por espectrometría de masas en tándem para su uso en el tamizaje neonatal en el suroccidente de Colombia

Abstract Introduction: Inborn errors of metabolism (IEM) represent an important public health problem due to current diagnosis and treatment limitations, poor life quality of affected patients, and consequent untimely child death. In contrast to classical methods, tandem mass spectrometry (MS/MS) has allowed simultaneous evaluation of multiple metabolites associated with IEM offering higher sensitivity, low false positive rates and high throughput. Aims: Determine concentration levels for amino acids and acylcarnitines in blood of newborns from Colombia, to establish reference values for further use in diagnosis of IEM. Methods: Implementation of a method to determine amino acids, acylcarnitines and succinylacetone in newborn dried blood spots using MS/MS, and its application in a cross-sectional study conducted in 891 healthy neonates from Cali and Quibdo cities is described. Results: fifty-seven analytes that allow the diagnosis of more than 40 different pathologies were tested. The method showed to be linear, precise and accurate. Healthy neonates 1-18 days of age were included, 523 from Cali and 368 from Quibdo; 52% male and 48% female. Age-related differences on the concentration levels of amino acids and acylcarnitines were observed whereas no significant differences by gender were found. Conclusion: The study has contributed to reveal the usual concentration levels of amino acids, acylcarnitines and succinylacetone that could be used as reference for the establishment of a newborn metabolic screening program in Colombia.

Resumen Introducción: Los Errores Innatos del metabolismo (EIM) representan un importante problema de salud pública debido a limitaciones en el tratamiento y diagnóstico oportuno, la pobre calidad de vida de los pacientes afectados, así como la muerte infantil prematura. Comparada con los métodos clásicos, la espectrometría de masas en tándem (MS/MS) ha permitido la evaluación simultánea de múltiples metabolitos asociados con EIM, con una alta sensibilidad, baja proporción de falsos positivos y alto rendimiento. Objetivos: Determinar los niveles de concentración de aminoácidos y acilcarnitinas en sangre de recién nacidos de Colombia, para establecer los valores normales para usarlos como referencia en el diagnóstico de EIM. Métodos: Aquí, se describe la implementación de un método para determinar aminoácidos, acilcarnitinas y succinilacetona en gotas de sangre seca de recién nacidos usando MS/MS, y su aplicación en un estudio de corte transversal realizado en 891 neonatos sanos de las ciudades de Cali y Quibdó. Resultados: Se evaluaron 57 analitos que permiten el diagnóstico de más de 40 patologías diferentes. El método mostró ser lineal, preciso y exacto. Se incluyeron neonatos sanos de 1-18 días de edad, 523 de Cali y 368 de Quibdó, 52% hombres y 48% mujeres. Se observaron diferencias en los niveles de concentración de aminoácidos y acilcarnitinas relacionadas con la edad, mientras que no se encontraron diferencias significativas por sexo. Conclusión: El estudio ha contribuido a revelar los niveles usuales de concentración de aminoácidos, acilcarnitinas y succinilacetona que pueden ser usados como referencia para el establecimiento del programa de tamizaje neonatal metabólico en Colombia.

Autistic children exhibit distinct plasma amino acid profile.

In order to ascertain whether autistic children display characteristic metabolic signatures that are of diagnostic value, plasma amino acid analyses were carried out on a cohort of 138 autistic children and 138 normal controls using reverse-phase HPLC. Pre-column derivatization of amino acids with phenyl isothiocyanate forms phenyl thio-carbamate derivates that have a λmax of 254 nm, enabling their detection using photodiode array. Autistic children showed elevated levels of glutamic acid (120 ± 89 vs. 83 ± 35 mmol/L) and asparagine (85 ± 37 vs. 47 ± 19 mmol/L); lower levels of phenylalanine (45 ± 20 vs. 59 ± 18 mmol/L), tryptophan (24 ± 11 vs. 41 ± 16 mmol/L), methionine (22 ± 9 vs. 28 ± 9 mmol/L) and histidine (45 ± 21 vs. 58 ± 15 mmol/L). A low molar ratio of (tryptophan/large neutral amino acids) × 100 was observed in autism (5.4 vs 9.2), indicating lesser availability of tryptophan for neurotransmitter serotonin synthesis. To conclude, elevated levels of excitatory amino acids (glutamate and asparagine), decreased essential amino acids (phenylalanine, tryptophan and methionine) and decreased precursors of neurotransmitters (tyrosine and tryptophan) are the distinct characteristics of plasma amino acid profile of autistic children. Thus, such metabolic signatures might be useful tools for early diagnosis of autism.

Tocotrienol supplementation in postmenopausal osteoporosis: evidence from a laboratory study

OBJECTIVE: Accelerated bone loss that occurs in postmenopausal women has been linked to oxidative stress and increased free radicals. We propose the use of antioxidants to prevent and reverse postmenopausal osteoporosis. This study aimed to examine the effects of tocotrienol, a vitamin E analog, on bone loss due to estrogen deficiency. Our previous study showed that tocotrienol increased the trabecular bone volume and trabecular number in ovariectomized rats. In the current study, we investigated the effects of tocotrienol supplementation on various biochemical parameters in a postmenopausal osteoporosis rat model. MATERIALS AND METHODS: A total of 32 female Wistar rats were randomly divided into four groups. The baseline group was sacrificed at the start of the study, and another group was sham operated. The remaining rats were ovariectomized and either given olive oil as a vehicle or treated with tocotrienol at a dose of 60 mg/kg body weight. After four weeks of treatment, blood was withdrawn for the measurement of interleukin-1 (IL1) and interleukin-6 (IL6) (bone resorbing cytokines), serum osteocalcin (a bone formation marker) and pyridinoline (a bone resorption marker). RESULTS: Tocotrienol supplementation in ovariectomized rats significantly reduced the levels of osteocalcin, IL1 and IL6. However, it did not alter the serum pyridinoline level. CONCLUSION: Tocotrienol prevented osteoporotic bone loss by reducing the high bone turnover rate associated with estrogen deficiency. Therefore, tocotrienol has the potential to be used as an anti-osteoporotic agent in postmenopausal women. .

Analysis of Risk Factors for Low Bone Mineral Density in Patients with Inflammatory Bowel Disease / 대한소화기학회지

BACKGROUND/AIMS: Several clinical risk factors for low bone mineral density (BMD) in the patients with inflammatory bowel disease (IBD) have been suggested. However, its prevalence and pathophysiology in Korean population have not been fully studied. The aim of this study was to investigate the prevalence and risk factors for low BMD in Korean IBD patient. METHODS: BMD of the lumbar spine and femur was evaluated using dual-energy X-ray absorptiometry in 30 patients with IBD. Biochemical parameters of bone metabolism, such as serum calcium, phosphorus, osteocalcin, and deoxypyridinoline were measured. The associations between low BMD and clinical parameters such as disease duration, disease activity, drug history, body mass index (BMI), and others were evaluated retrospectively using medical records. RESULTS: Low BMD at the lumbar spine or femur was observed in 63.3% of the patients, and there was no significant difference between the patients with Crohn's disease and ulcerative colitis. Clinical and biochemical parameters were irrelevant to BMD. In the patients without glucocorticoid treatment prior to BMD measurement, already 50.0% of patients had low BMD. CONCLUSIONS: Low BMD is a common feature in Korean IBD patients, even those who do not use glucocorticoid. The multiple factors may be involved in the pathogenesis of low BMD. Therefore, BMD should be examined in all IBD patients, irrespective of glucocorticoid treatment.

Cuantificación de aminoácidos en plasma empleando Cromatografía Líquida de Alta Eficiencia / Plasma amino acid quantification using High Performance Liquid Chromatography

Las aminoacidopatías son errores innatos del metabolismo intermediario de los aminoácidos. Su confirmación diagnóstica y seguimiento se realiza con la cuantificación de aminoácidos libres en fluidos biológicos por técnicas como la cromatografía líquida de alta eficiencia (HPLC), para lo que es necesario comparar con valores de referencia normales. La población colombiana no cuenta con estos valores disponibles y el diagnóstico es realizado por comparación con los de otras poblaciones. En el presente trabajo se obtuvieron valores de referencia de aminoácidos en plasma en una población de niños (n=36) y adultos no afectados (n=17), mediante HPLC por derivatización postcolumna con ninhidrina. Los valores de referencia obtenidos fueron ligeramente más elevados que los informados para otras poblaciones y permitieron la identificación de doce casos de aminoacidopatías, incluyendo fenilcetonuria clásica, hiperfenilalaninemia, hiperglicinemia no cetósica, desórdenes del ciclo de la urea, tirosinemia. La implementación de la cuantificación de aminoácidos por HPLC y la obtención de los valores de referencia de aminoácidos en plasma permitirán aumentar el conocimiento sobre la incidencia de las aminoacidopatías en el país para garantizar, junto con otros factores, su diagnóstico preciso y oportuno y la implementación de un adecuado seguimiento nutricional.

Aminoacidopathies are inborn errors of the amino acid intermediary metabolism. The benchmark method used for their diagnosis and monitoring is the quanti!cation of free amino acids in biological fluids using High Performance Liquid Chromatography (HPLC), which needs to be compared against normal reference values. However, those amino acid reference values are not available for the Colombian population and the diagnosis is usually made using values from American or European populations. In this work, plasma amino acid reference values in non-affected children (n=36) and adults (n=17) were established, using an HPLC method with a postcolumn derivatization with ninhidrine. Plasma amino acid reference values in a Colombian population were slightly higher compared with those reported for other populations, and enabled the identification of twelve aminoacidopathies including urea cycle disorders, phenylketonuria, hyperphenylalaninemia, nonketotichyperglycinemia, hepatorrenaltyrosinemia and maple syrup urine disease. The implementation of amino acid cuantification by HPLC and the construction of plasma amino acid reference values is very useful for a suitable and precise diagnosis of amino acid disorders, the implementation of proper nutritional treatments, and an increased knowledge of aminoacidopathy incidence in Colombia.

Inborn errors of metabolism revealed by organic acid profile analysis in high risk Egyptian patients: six years experience

To determine the prevalence and types of inborn errors of amino acid or organic acid metabolism in a group of high risk Egyptian children with clinical signs and symptoms suggestive of inherited metabolic diseases. 117 [79 males = 67.5% and 38 females = 32.5%] high risk patients with signs and symptoms of a metabolic disorder were studied, their ages ranged from 3 days to 12 years. Analysis of urine organic acids by gas chromatography/mass spectrometry [GC/MS] was performed to all patients. 22[18.8% of the total] cases were diagnosed with different types of aminoacidopathies or organic acidurias. The disease profile showed increased lactate in 12 cases [54%], glutaric aciduria type I 3 cases [13%], phenylketonuria 2 cases [9%], maple syrup urine disease 1 case [4.5%], glutaric aciduria type II 1 case [4.5%], methylmalonic aciduria 1 case [4.5%], Canavan disease 1 case [4.5%] and non ketotic hyperglycemia 1 case [4.5%]. The results demonstrate the importance of the organic acid profile in the diagnosis of high risk patients. The diagnosed organic acid pattern in this study showed that 10.2% of the patients had a mitochondrial energy defect

La dimetilarginina asimétrica, estructura e implicaciones patológicas / Asymmetric dimethylarginine, structure and pathological implications

La ateroesclerosis, es una enfermedad crónica, sistémica, inmuno-inflamatoria que afecta a la íntima arterial. La disfunción endotelial es la primera fase en la ateroesclerosis La disfunción endotelial está caracterizada por un daño y pérdida de la monocapa celular que cubre el interior de los vasos sanguíneos, denominada endotelio. Uno de los principales mediadores ara el mentenimieno de la integridad del endotelio, es el óxido nítrico (ON). La Dimetilarginina asimétrica (DMMA), es un inhibidor endógeno de la enzima sintasa del Óxido Nítrico (SON); se ha sugerido que DMAA sirve como un marcador de disfunción endotelial en enfermedades cardiovasculares. Asimismo, la DMAA representa un factor de riesgo para mortalidad cardiovascular, progresión de enfermedad crónica renal. Se ha encontrado valores elevados de DMAA en diferentes condiciones como hipercolesterolemia, aterosclerosis, hipertensión, insuficiencia renal crónica, insuficiencia crónica del corazón, diabetes y disfunsión eréctil.

Atherosclerosis is an immune inflammatory systemic, arterial disease. Endothelial dysfunction is the first stage in aterosclerosis. Atherosclerosis develops because of reactions occurring in vessel wall beginning with response to enothelial injury. Endothelial dysfunction is characterized with impairment and loss of monolayer cells covering the inside of the vessels, which is enothelium. One of the main mediators for the maintenance of the integrity of endothelium is Nitric Oxide (NO). The asymmtric Dimethilarginine (ADMA), is an endogenous inhibitor of the enzyme Nitric Oxide Synthase (NOS). ADMA has been suggested to serve as a biomarker of endothelial dysfunction in cardiovascular diseases. ADMA is a risk factor for endothelial dysfunction, cardiovascular mortality, and progression of chronic kidney disease. Elevated values of ADMA have been found in hypercholesterolemia, atherosclerosis, hypertension, chronic renal insufficiency, heart chronic failure, diabetes and erectile dysfunction.

Plasma amino acids in pregnancy, placental intervillous space and preterm newborn infants

Plasma amino acid levels have never been studied in the placental intervillous space of preterm gestations. Our objective was to determine the possible relationship between plasma amino acids of maternal venous blood (M), of the placental intervillous space (PIVS) and of the umbilical vein (UV) of preterm newborn infants. Plasma amino acid levels were analyzed by ion-exchange chromatography in M from 14 parturients and in the PIVS and UV of their preterm newborn infants. Mean gestational age was 34 ± 2 weeks, weight = 1827 ± 510 g, and all newborns were considered adequate for gestational age. The mean Apgar score was 8 and 9 at the first and fifth minutes. Plasma amino acid values were significantly lower in M than in PIVS (166 percent), except for aminobutyric acid. On average, plasma amino acid levels were significantly higher in UV than in M (107 percent) and were closer to PIVS than to M values, except for cystine and aminobutyric acid (P < 0.05). Comparison of the mean plasma amino acid concentrations in the UV of preterm to those of term newborn infants previously studied by our group showed no significant difference, except for proline (P < 0.05), preterm > term. These data suggest that the mechanisms of active amino acid transport are centralized in the syncytiotrophoblast, with their passage to the fetus being an active bidirectional process with asymmetric efflux. PIVS could be a reserve amino acid space for the protection of the fetal compartment from inadequate maternal amino acid variations.

The Effect of Dialysis Membrane Flux on Amino Acid Loss in Hemodialysis Patients

We examined whether high flux membranes (HF) may induce a greater loss of amino acids compared to low flux membranes (LF). Ten hemodialysis patients participated in this study. Pre- and post-hemodialysis plasma amino acid profiles were measured by reverse-phase high pressure liquid chromatography for both HF and LF. We measured the dialysate amino acid losses during hemodialysis. The reduction difference for plasma total amino acid (TAA), essential amino acid (EAA), and branch chained amino acid (BCAA) was not significantly different in comparisons between the two membranes. (HF vs. LF; TAA 66.85+/-30.56 vs. 53.78+/-41.28, p=0.12; EAA 14.79+/-17.16 vs. 17.97+/-28.69, p=0.12; BCAA 2.21+/-6.08 vs. 4.16+/-10.98 mg/L, p=0.13). For the HF, the reduction in plasma amino acid levels for TAA and EAA were statistically significant. Although it was not statistically significant, the dialysate losses of BCAA were greater than the reduction in plasma (plasma reduction vs. dialysate loss; HF 2.21+/-6.08 vs. 6.58+/-4.32, LF 4.16+/-10.98 vs. 7.96+/-3.25 mg/L). HF with large pores and a sieving coefficient do not influence dialysate amino acid losses. Hemodialysis itself may influence the dialysate amino acid losses and may have an effect on protein metabolism.

Neonatal Intrahepatic Cholestasis Caused by Citrin Deficiency in Korean Infants

Citrin is a liver-type mitochondrial aspartate-glutamate carrier encoded by the SLC25A13 gene, and its deficiency causes adult-onset type II citrullinemia and neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD). Here, the authors investigated clinical findings in Korean infants with NICCD and performed mutation analysis on the SLC25A13 gene. Of 47 patients with neonatal cholestasis, three infants had multiple aminoacidemia (involving citrulline, methionine, and arginine) and galactosemia, and thus were diagnosed as having NICCD. Two of these three showed failure to thrive. The laboratory findings showed hypoproteinemia and hyperammonemia, and liver biopsies revealed micro-macrovesicular fatty liver and cholestasis. The three patients each harbored compound heterozygous 1,638-1,660 dup/ S225X mutation, compound heterozygous 851del4/S225X mutation, and heterozygous 1,638-1,660 dup mutation, respectively. With nutritional manipulation, liver functions were normalized and catch-up growth was achieved. NICCD should be considered in the differential diagnosis of cholestatic jaundice in Korean infants.

Effect of melatonin on some bone turnover markers in ovarectomized rats

This study was carried out to evaluate the effect and the mechanism of action of melatonin on some bone markers in ovarectomized bone loss in rats. 32 female albino rats underwent either bilateral laparotomy [sham, n=8] or bilateral ovarectomy [Ovx, n=24]. The Ovx rats were divided into 3 groups, each of 8 rats; Vehicle-treated [Ovx], estrogen-treated [E2] and melatonin-treated [Mlt] group. After 14 weeks treatment, blood and urine were collected. Serum osteoprotegerin [OPG], inhibin, follistatin, and alkaline phosphatase [ALPase] were determined as bone markers. In addition, urinary Deoxypyridinoline [uDPD] was assayed. Serum OPG, inhibin and follistatin levels significantly decreased upon Ovx. They increased upon either treatment with E2 or Mlt with non- significant difference in between as compared to Ovx group. In addition, serum ALPase and uDPD significantly increased on Ovx and decreased with either therapy as compared to Ovx one with non- significant difference between both therapies. The results revealed that administration of Mlt inhibited high bone turnover and prevented calcium loss in ovarectomized rats. This may be through increasing OPG, inhibin and/or follistatin levels. Mlt could be a candidate for the treatment of postmenopausal osteoporosis

Elevated amniotic fluid amino acid levels in fetuses with gastroschisis

Our objective was to measure maternal plasma and amniotic fluid amino acid concentrations in pregnant women diagnosed as having fetuses with gastroschisis in the second trimester of pregnancy. Twenty-one pregnant women who had fetuses with gastroschisis detected by ultrasonography (gastroschisis group) in the second trimester and 32 women who had abnormal triple screenings indicating an increased risk for Down syndrome but had healthy fetuses (control group) were enrolled in the study. Amniotic fluid was obtained by amniocentesis, and maternal plasma samples were taken simultaneously. The chromosomal analysis of the study and control groups was normal. Levels of free amino acids and non-essential amino acids were measured in plasma and amniotic fluid samples using EZ:fast kits (EZ:fast GC/FID free (physiological) amino acid kit) by gas chromatography (Focus GC AI 3000 Thermo Finnigan analyzer). The mean levels of essential amino acids (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine) and non-essential amino acids (alanine, glycine, proline, and tyrosine) in amniotic fluid were found to be significantly higher in fetuses with gastroschisis than in the control group (P < 0.05). A significant positive correlation between maternal plasma and amniotic fluid concentrations of essential and nonessential amino acids was found only in the gastroschisis group (P < 0.05). The detection of significantly higher amino acid concentrations in the amniotic fluid of fetuses with a gastroschisis defect than in healthy fetuses suggests the occurrence of amino acid malabsorption or of amino acid leakage from the fetus into amniotic fluid.

HD is beneficial for enzymatic conversion of some amino-acids in the elderly

Many different causes of abnormal amino acid profile in uremic patients including: inadequate nutritional intake, uremic disturbances in amino acid metabolism, loss or fibrosis of renal tissues, metabolic acidosis and hormonal derangement. Some of these factors; such as metabolic acidosis are particularly corrected with dialytic therapy; but others such as decreased intake or hormonal disturbances may persist or worsen after initiation of dialysis. This study was done to investigate the plasma amino acids profile in uremic elderly patients. The present study was carried out on three matched groups: [G1] on HD, [G2] CRF and a control. A significant uniform decrease of Threonine, Valine and Leucine in both HD and CRF. However, a peculiar situation of significant increase in phenylalanine in HD in comparison to CRF and to control. This is similar to the significant increase of Arginine in HD group in comparison to the others. In contrast, phenylalanine was significantly decreased in CRF in comparison to both HD group and the control. The latter was similar to the decrease of Leucine in CRF in comparison to the other two groups. Hence, Phenylalanine was the only AA that was found to be significantly increased in HD and significantly decreased in CRF in comparison to control. Moreover, only Phenylalanine and Arginine were significantly increased in HD group in contrast to the rest of the essential amino-acids, which showed either decrease or no change. Tyrosine and lysine were significantly lower in pre -dialysis CRF group in comparison to patients on HD and the control. This may imply that HD can correct the deficiency of tyrosine and lysine in uremic patients probably due to less inhibition of phenylalanine hydrorxylase. Inter-conversion of phenylalanine to tyrosine was reported to be impaired in CRF; whereas tyrosine metabolism per se does not seem to be grossly affected by uremia. However; Serine was significantly lower in both groups of uremic patients in the current study compared with the control group, with no significant difference in-between pre -dialysis patients and patients on HD. In conclusion, our study showed that HD may be beneficial in restoring the enzymatic turnover of certain amino-acids including: Phenylalanine hydroxylase to normalize tyrosine plasma level, Arginine synthetase to convert citrulline to Arginine. On the other hand, HD may be injurious to the production of other amino-acids like serine due to complete lost of the renal tissue that is responsible of its production from glycine

Recurrent stupor due to lysinuric protein intolerance.

Recurrent stupor in children is an uncommon clinical problem with a wide differential diagnosis; inherited metabolic disorders account for a vast majority. We report a 9-year-old girl with recurrent episodes of stupor. Initial episode was treated as viral encephalitis and the second episode was managed as non-convulsive status epilepticus. Hyperammonemia was detected in the last episode. Metabolic work-up after dietary protein challenge revealed classical biochemical features of lysinuric protein intolerance. She was managed with protein-restricted diet, which resulted in marked neurological improvement. LPI is a rare inherited metabolic disorder due to membrane transport defect of cationic amino acids.

Pharmacokinetics of Glutathione and Its Metabolites in Normal Subjects

To determine the loading and maintenance dosage of glutathione (GSH) for patients suffering from reactive oxygen species (ROS) injury such as acute paraquat intoxication, a kinetic study of reduced GSH was performed in synchrony with that of cysteine (Cys), cystine (Cys2), and methionine (Met). Human subject's porticipitation was voluntary. The effective dose of Cys, Cys2, and Met against ROS in fibroblast cells generated by paraquat was assessed using laser scanning confocal microscopy. Both Cys and Met suppressed ROS in a dose-dependent manner at concentrations of 1-1,000 micrometer; the concentration required to suppress ROS by 50% was 10 micrometer for Cys and 50 micrometer for Met. Using metabolite kinetics with the assumption that Cys and Met are the metabolites of GSH, expected concentrations of Cys and Met of above 20 and 50 micrometer were estimated when GSH was administered at 50 mg/kg body weights every 205.4 min for Cys and 427.4 min for Met.

Effect of High-Dose Intravenous N-acetylcysteine on the Concentration of Plasma Sulfur-Containing Amino Acids

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.

Perfil de aminoácidos plasmáticos en adolescentes saludables embarazadas de Maracaibo, Venezuela / Plasma amino acids profile of healthy pregnant adolescents in Maracaibo, Venezuela

One hundred female adolescents (13-18 y) were clinical and anthropometrically studied to select only those with adequate nutrition. Most adolescents belonged to IV socio-economic stratum families (worker class). Height, weight, age, body mass index and medial arm circumference were used as anthropometric parameters. After screening, only 41 non pregnant girls (control) and 42 pregnant girls with adequate nutrition were selected to analyze plasma amino acids. Fasting peripheral venous blood was drawn, and plasma amino acids were analyzed by HPLC. Amino acid concentrations were expressed as umol/L +/- SE. SAS/STAT program was used for statistical analysis. Amino acid values of control adolescent group were found in ranges reported by other investigators, with slight variations, mostly in diminution, presumably due to nutritional, metabolic or genetic conditions of people living in tropical regions. In pregnant healthy adolescents, distributed according to gestational age: < 32 weeks (n = 30) and > 32 weeks (n = 12), a diminution of total molar plasma amino acids was found, by comparing with control values. Ten amino acids (Pro, Gly, Gln, Arg, Ser, Orn, Tau, Leu, Thr and Val) appeared significantively diminished throughout gestation, being Gly. Gln and Arg most affected since earlier weeks. During the 2nd period. Thr and Val increased their grade of affectation; whereas some amino acids values (Orn, Pro and Tau) tended to recuperate. Several of affected amino acids are gluconegoenic, thus, they could be utilized to supply the energy required by the pregnant adolescent against her double stress: the fetus development and her own development. The plasma amino acid values reported in both, healthy non pregnant and pregnant adolescents, could be taken as regional referential profile of plasma amino acids in this poblational group for further research on adolescent and fetal--maternal malnutrition.

United Arab Emirates National Newborn Screening Programme: an evaluation 1998-2000

To evaluate the United Arab Emirate National Newborn Screening Programme we compared coverage, timeliness of programme indicators [age at sampling, recall and treatment initiation, timing of specimen delivery and laboratory results] and specimen quality with international st and ards. Recall rate, sensitivity, specificity, positive predictive values and relative incidence rates for phenylketonuria [PKU] and congenital hypothyroidism [CH] were calculated. Investigations for hypothyroidism included thyroid function studies [T3, T4, fT4 and TSH], technetium-99m thyroid scan when possible and thyroglobulin and thyroid antibodies when indicated. PKU investigations included plasma amino acids and measurement of biopterin defects. In the 6 years before December 2000, 138,718 neonates were screened. Relative incidences for CH and for classic PKU were 1:1570 and 1:20,050 respectively