Two parenteral amino acid solutions and plasma levels of amino acids in the neonate: A randomized trial

OBJECTIVE

In neonates on total parenteral nutrition (TPN), amino acids may be a risk factor for developing total parenteral nutrition-associated cholestasis (TPNAC). We aimed, first, to compare methionine, cysteine, and taurine plasma levels between neonates on TPN who were receiving an intravenous amino acid solution based on a breast milk aminogram and those on an intravenous solution of pediatric amino acids based on an umbilical cord aminogram, and second, to determine the frequency of TPNAC.

METHODS

A double-blind randomized controlled trial was conducted. Ninety-four neonates with a birthweight of 1000g or more and a gestational age of 30 wk or older were admitted and enrolled. Blood samples were obtained at 0, 7, and 14 d of TPN, and plasma amino acid concentrations were determined by ultra-high-resolution liquid chromatography. Continuous variables were compared using the Wilcoxon rank-sum test or Student's t test; categorical variables were compared using the Fisher exact test.

RESULTS

Thirty-five neonates completed the study (Primene, n = 14; TrophAmine, n = 21). On day 14, methionine plasma concentrations were significantly lower in the Primene group than in the TrophAmine group (27 µmol/L versus 32.9 µmol/L, P = 0.044); the taurine concentration was significantly higher in the same group (72.4 µmol/L versus 45.3 µmol/L, P < 0.0001). There were no differences in TPNAC incidence.

CONCLUSIONS

Administering an intravenous solution of pediatric amino acids based on the umbilical cord aminogram yielded a higher taurine and lower methionine plasma concentration than did administering a similar solution based on the breast milk aminogram.

Maíz nixtamalizado suplementado con un concentrado de proteínas de sardina para mejorar el valor biológico de las tortillas

Introducción

La mayor parte de la población rural en México adquiere casi la mitad de su energía de la tortilla de maíz y sus fuentes de proteína son principalmente de origen vegetal.

Objetivo

Obtener un concentrado de proteína de sardina para adicionar harina de maíz e identificar la concentración que proporcione la mejor calidad biológica de las tortillas sin modificar sus características físicas y sensoriales.

Método

Obtención de un concentrado de proteína de sardina y elaboración de tortillas con harina de maíz suplementada con diferentes concentraciones de proteína. Las características físicas y sensoriales de las tortillas fueron evaluadas por panelistas no entrenados. La calidad biológica de las tortillas se analizó en un modelo murino (crecimiento y la relación de eficiencia de proteína, PER). Para el análisis se utilizó estadística paramétrica.

Resultados

Se obtuvo un concentrado de proteína con 70.48 g/100 g. La suavidad, inflado, doblado y calidad de las tortillas preparadas con las mezclas con 0.63-3.75 % de proteínas de sardina fueron comparables con los de las tortillas elaboradas con harina no adicionada. El crecimiento de las ratas alimentadas con tortillas adicionadas fue mayor que el de las alimentadas con harina no adicionada; la diferencia fue significativa a partir de la concentración de 3.75 % (p < 0.05). El PER de las tortillas con 3.75 % de proteínas de sardina fue de 2.41, comparable al de la proteína de referencia (caseína).

Conclusión

La harina de maíz adicionada con proteínas de sardina en una proporción de 96.25:3.75 % mejora el valor biológico de las tortillas sin alterar sus características físicas y sensoriales.

Introduction

Most part of the rural population in Mexico obtains almost half its energy from corn tortilla, and its sources of protein are mainly of vegetal origin.

Objective

To obtain a concentrate of sardine protein (SP) to supplement corn flour, and to identify which concentration provides corn tortillas with a better biological value, without modifying its physical and sensorial characteristics.

Method

Obtainment of the SP concentrate, preparation of tortillas with corn flour and different SP concentrations, assessment of tortillas physical and sensorial characteristics by untrained panelists, assessment of biological quality in a murine model (growth and protein efficiency ratio [PER]). Parametric statistics was used.

Results

A protein concentrate of 70.48 g/100 g was obtained. Smoothness, blistering, foldability and quality of the tortillas prepared with mixtures containing 0.63-3.75% of SP were comparable to those of tortillas prepared with non-supplemented flour. The growth of rats fed supplemented tortillas was superior; the difference was significant with ≥ 3.75% concentrations (p < 0.05). The PER of tortillas with 3.75% of SP was 2.41, which was comparable to that of the reference protein (casein).

Conclusion

SP-supplemented corn flour at a 96.25:3.75% ratio improves the biological value of tortillas without modifying their physical and sensorial characteristics.

Longitudinal Analysis of the Interaction Between Obesity and Pregnancy on Iron Homeostasis: Role of Hepcidin

BACKGROUND AND AIMS

When pregnancy occurs in obese women, two opposite mechanisms for iron homeostasis concur: increased need for available iron to support erythropoiesis and decreased iron mobilization from diets and stores due to obesity-related inflammation linked to overexpressed hepcidin. Few studies have examined the role of hepcidin on maternal iron homeostasis in the context of obese pregnancy. The aim of the study was to evaluate the combined effect of maternal obesity and pregnancy on hepcidin and maternal iron status while accounting for inflammation and iron supplementation.

METHODS

We conducted a secondary analysis of a cohort of pregnant women recruited from a referral obstetric hospital in Mexico City. Circulating biomarkers of iron status (hepcidin, ferritin [SF], transferrin receptor [sTfR], erythropoietin [EPO]), and inflammation (C-reactive protein [CRP], tumor necrosis factor-[TNF]α, and interleukin-[IL]6) were determined monthly throughout pregnancy. Repeated measures ANOVA and logistic regression models were used for statistics.

RESULTS

Twenty-three obese (Ob) and 25 lean (Lc) women were studied. SF and hepcidin declined, and EPO and sTfR increased throughout pregnancy in both groups. sTfR increased more in Ob than in Lc (p = 0.024). The smallest hepcidin decline occurred in iron-supplemented Ob women compared to non-supplemented Lc women (p = 0.022). The risk for iron deficiency at the end of pregnancy was higher for Ob than for Lc (OR = 4.45, 95% CI = 2.07-9.58) after adjusting for iron supplementation and hepcidin concentration.

CONCLUSION

Pre-gestational obesity increases the risk of maternal iron deficiency despite iron supplementation. Overexpressed hepcidin appears to be a potential mechanism.

Serial determinations of asymmetric dimethylarginine and homocysteine during pregnancy to predict pre-eclampsia: a longitudinal study

OBJECTIVE

To evaluate the usefulness of serial determinations of asymmetric dimethylarginine (ADMA) and homocysteine (Hcy) concentrations during pregnancy to predict pre-eclampsia, taking into account maternal obesity and B vitamin status.

DESIGN

Longitudinal study.

SETTING

Two obstetric referral hospitals.

SAMPLE

Two hundred and fifty-two of 411 women invited to participate in the study.

METHODS

The women made monthly visits from ≤20 weeks of gestation until delivery for measurements of plasma ADMA, Hcy, and vitamins B6 , B12, and folic acid, and for the recording of clinical information.

MAIN OUTCOME MEASURE

Early elevations in plasma ADMA and Hcy related to the development of pre-eclampsia.

RESULTS

Of the 252 women who completed the study, 179 had no complications, 49 developed pre-eclampsia, and 24 presented with complications other than pre-eclampsia. ADMA and Hcy increased gradually throughout pregnancy in the pre-eclampsia group, independent of maternal B-vitamin status and obesity, but remained constant in women with no complications. Relative to the preceding month, ADMA and Hcy levels increased 1 month prior to the onset of pre-eclampsia: 124 ± 27 nmol (P < 0.001) and 1177 ± 278 nmol (P = 0.001), respectively, in the pre-eclampsia group. The group of women with no complications did not show any significant changes. Increases of 80 nmol ADMA and 1000 nmol Hcy at 1 month prior to the onset of pre-eclampsia demonstrated the best potential for prediction.

CONCLUSIONS

Increased ADMA and Hcy levels precede clinical manifestations of pre-eclampsia. Therefore, serial determinations of their concentrations may be helpful in identifying women at risk.

TWEETABLE ABSTRACT

Increased ADMA and Hcy precede clinical pre-eclampsia and may identify women at risk.

[Interactions between markers of endothelial damage (homocysteine and asymmetric dimethylarginine) and antioxidants and B-vitamins in preeclamptic women]

BACKGROUND

Preeclampsia is a pregnancy-related pathological condition triggered by an abnormal placentation which produces endothelial dysfunction (ED). ED, in turn, is associated with an increase in homocysteine (hcy) and asymmetric dimethylarginine (ADMA); these molecules are also increased when some of the B-vitamins are deficient. It is unclear whether increases in hcy and ADMA during preeclampsia are the result of ED, or the consequence of a B-vitamin deficiency.

OBJECTIVE

To evaluate hcy, ADMA, folic acid (FA), vitamin B6 and B2 concentrations in patients with preeclampsia.

METHODS

In a cross-sectional design 19 patients with severe preeclamp- sia (preeclampsia) and 57 with normal pregnancy (no-preeclampsia), paired by gestational age and body mass index, were studied. Plasma hcy, ADMA, FA and vitamins B6 and B12 were determined. Non-parametric statistics was used for between-groups comparisons and regression analyses to evaluate interactions among molecules.

RESULTS

72% of women were vitamin B deficient, 40% were deficient of B12 and 4% of FA. Preeclamptic patients presented hcy and ADMA concentrations higher than no-preeclamptic ones. Inferential analyses demonstrated that: hcy and ADMA are increased during preeclampsia independently from vitamins blood concentration; that the risk for pre- eclampsia is associated with high hcy but not with vitamins deficiency; and that the ratio L-arginine:ADMA decreases the preeclampsia risk.

CONCLUSION

In patients with preeclampsia, increases of hcy and ADMA are associated with ED, but not with deficiency of the vitamins involved in their metabolism.

Validity and reliability of the 13C-methionine breath test for the detection of moderate hyperhomocysteinemia in Mexican adults

BACKGROUND

Hyperhomocysteinemia (Hhcy) is considered an independent risk factor for vascular diseases and, more recently, for dementia. The methionine loading test (MLT) is useful for diagnosing additional subjects with moderate Hhcy. However, it is a complex and time-consuming procedure. A noninvasive test for the diagnosis of moderate Hhcy is desirable.

METHODS

The study protocol consisted of three consecutive visits. During the first visit, we performed an MLT to characterize the Hhcy status of 75 healthy adult subjects. For the breath test protocol, we selected a subsample and assigned to the control group 17 subjects with fasting and post-loading homocysteine (Hcy) ≤12 and <42.3 μmol/L, respectively, and to the Hhcy group 16 subjects with fasting Hcy ≤12 and >42.3 μmol/L after loading. Selected subjects were requested to have a second visit to perform a breath test within 1-4 weeks following the MLT test and received an oral dose of 2.5 mg/kg of 1-13C-methionine dissolved in water. Breath samples were collected at basal, 20, 40, 60, 80, 100 and 120 min (test 1). The same procedure was repeated within 1 week (test 2).

RESULTS

MLT was useful for diagnosing almost twice the number of individuals with Hhcy (24%) in comparison with the fasting determination alone (13.3%). The 13C-methionine breath test reported a sensitivity of 81.3% and a specificity of 64.7% against the MLT. The coefficient of variation between breath test 1 and breath test 2 was 9.0±5.4%.

CONCLUSIONS

The 13C-methionine breath test is a valid and reliable method for identifying subjects with moderate Hhcy.

[Homocysteine after a methionine load in healthy subjects with adequate B-vitamin status]

BACKGROUND

Plasma homocysteine (Hcy) determination at 6-8 h after an oral methionine load (OML) allows for identification of some, but not all, individuals at risk to develop cardiovascular disease. It is probable that in some cases the Hcy increases occur later, or it elevates between normal ranges but in a sustained manner. However, the entire Hcy response curve has not been described. We undertook this study to determine Hcy concentrations from baseline to 24- and 48-h after an OML in non-B-vitamin deficient adult subjects with other risk factors for high levels of Hcy such as smoking and overweight.

METHODS

In a cross-over, clinical design, Hcy concentrations were determined at 2-h intervals throughout 12 h and at 24 h and 48 h after an OML (0.1 g/kg). Hcy and vitamin B6 (VB6) concentrations were measured by high-performance liquid chromatography (HPLC). Folic acid (FA) and vitamin B12 (VB12) were measured by radioimmunoassay (RIA). Statistical analysis included delta values and areas under the curve. Student t-test and repeated measurement analyses were conducted to control for confounders.

RESULTS

Twenty-nine subjects with adequate Hcy, FA, VB6 and VB12 status were included. The maximum Hcy concentration occurred 8 h after the load and returned to baseline concentrations after 24 h. All subjects presented Hcy after the load within normal ranges, but smoking and overweight synergistically influenced the response to the challenge, producing a sustained elevation after the dose.

CONCLUSIONS

Hcy concentrations after an OML remained above baseline for at least 24 h. Smoking and overweight affected the response to the methionine challenge.

Vitamins A, and C and folate status in Mexican children under 12 years and women 12-49 years: a probabilistic national survey

OBJECTIVE

To describe the epidemiology of Vitamin A and C and folic acid deficiencies and their association with sociodemographic and dietary factors in a national probabilistic sample of Mexican women and children.

MATERIAL AND METHODS

This is a probabilistic sample from the National Nutrition Survey 1999 (ENN-99) including 1,966 children and 920 women. Vitamins A and C were measured in serum by high-performance liquid chromatography, and folic acid in total blood by a microbiological method. Determinants for such deficiencies were explored by multiple regression models.

RESULTS

Vitamin A deficiency (retinol < 10 micrograms/dl) was rare in both children and women. But subclinical deficiency (retinol > 10 and < 20 micrograms/dl) was present in 25% of children. The likelihood of subclinical deficiency of vitamin A was less in older children (OR = 0.98, p = 0.01) and in women with higher body mass index (OR = 0.93, p = 0.01). About 30% of children < 2 years of age and 40% of women were vitamin C deficient. The likelihood of vitamin C deficiency was less in children and women as socioeconomic level increased (OR = 0.69, p = 0.03, and OR = 0.80, p = 0.04), and higher in older women (OR = 1.02, p = 0.05). The prevalence of folate deficiency varied in children (2.3 to 11.2), in women it was 5%. Folate deficiency was less in children of higher socioeconomic level (OR = 0.62, p = 0.01), and in those eating more vegetables (OR = 0.22, p = 0.01).

CONCLUSIONS

The high prevalence of subclinical deficiency of vitamin A in children is indicative of risk of further deterioration under adverse circumstances. Vitamin C deficiency in both children and women implies in addition diminished ability for iron absorption. The English version of this paper is available too at: http://www.insp.mx/salud/index.html.