Gabriel Manjarrez

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OBJECTIVE To evaluate whether the free fraction of L-tryptophan (L-Trp) and the N1/P2 component of the auditory evoked potentials (AEPs) are associated with impaired brain serotonin neurotransmission in infants with intrauterine growth restriction (IUGR). STUDY DESIGN We measured free, bound, and total plasma L-Trp and recorded the N1/P2 component of AEP(More)
It is known that L-tryptophan stimulates serotonin synthesis in the brain and serotonergic neuronal activity. Also, the N1/P2 component of auditory evoked potential (AEP) is a good indicator of this activity in the auditory cortex. In the present work, we examined the effect of the L-tryptophan administration on electric activity of the auditory cortex(More)
BACKGROUND The present study was aimed to obtain information on the interaction kinetics of L-tryptophan (L-Trp) with plasma albumin from normal, intrauterine growth-restricted (IUGR) and nutritionally recovered (NR) newborn infants. METHODS A case study cohort was planned in 37 newborns during the first 3 months of life. At birth two groups were formed.(More)
In the course of the present research in school children with insulin-dependent diabetes mellitus, we observed that the free fraction of L-tryptophan, the free fraction of L-tryptophan/total L-tryptophan, and the free fraction of L-tryptophan/neutral amino acids ratios, are significantly reduced. The decrease of free fraction of L-tryptophan in plasma with(More)
OBJECTIVE To determine in children with type 1 diabetes the plasma free fraction of L-tryptophan (FFT) and the intensity-dependent auditory-evoked potentials (IDAEPs) as indicators of possible changes in brain serotonergic neurotransmission. RESEARCH DESIGN AND METHODS A prospective and comparative study was performed in children with type 1 diabetes and(More)
In the present work we confirm that gestational malnutrition effects body and brain composition and results in an activation of the synthesis of the brain neurotransmitter 5-hydroxytryptamine. These results also demonstrate more activity of the rate-limiting enzyme tryptophan hydroxylase in the malnourished fetal and postnatal brain. However, the activity(More)
BACKGROUND/AIMS To determine if the slope of the amplitude/stimulus intensity function (ASF) of the N1/P2 component of the auditory evoked potential was increased in women with type 2 diabetes reflecting a low brain serotonergic activity in the auditory cortex. METHODS In a comparative study in women with type 2 diabetes and controls, we measured free,(More)
This study confirms observations made in a former study of plasma of preterm and term newborn infants with intrauterine malnutrition during the first month of life and extends to the lactational period. The free fraction of L-tryptophan, the precursor amino acid of brain serotonin synthesis, is significantly elevated up to 3 months of age. According to(More)
In the present study we report results concerning 5-hydroxytryptamine (5-HT) metabolism in two groups of small for date (SFD) human babies (gestational age 36 and 3 weeks), who suffered intrauterine nutritional restriction. A complementary study in the brain of rat fetuses with two types of intrauterine deprivation, in which brain L-tryptophan (L-Trp),(More)
In the present study we report results on the possible mechanism of inhibition of tryptophan-5-hydroxylase activity induced by insulin-dependent diabetes mellitus (IDDM). Kinetic experiments were done with different L-tryptophan (L-Trp) concentrations in the rat brain at different days of evolution of the disease. Additionally, different activation(More)