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Purpose: Childhood obesity is an increasing problem and is accompanied by metabolic disturbances. Recently, we have identified 14 serum metabolites by a metabolomics approach (FIA-MS/MS), which showed altered concentrations in obese children as compared to normal-weight children. Obese children demonstrated higher concentrations of two acylcarnitines and lower levels of three amino acids, six acyl-alkyl phosphatidylcholines, and three lysophosphatidylcholines. The aim of this study was to analyze whether these alterations normalize in weight loss., Methods: We analyzed the changes of these 14 metabolites by the same metabolic kit as in our previous study in serum samples of 80 obese children with substantial weight loss (BMI-SDS reduction >0.5) and in 80 obese children with stable weight status all participating in a 1-year lifestyle intervention., Results: In the children without weight change, no significant changes of metabolite concentrations could be observed. In children with substantial weight loss, glutamine, methionine, the lysophosphatidylcholines LPCaC18:1, LPCaC18:2, and LPCa20:4, as well as the acyl-alkyl phosphatidylcholine PCaeC36:2 increased significantly, while the acylcarnitines C12:1 and C16:1, proline, PCaeC34:1, PCaeC34:2, PCaeC34:3, PCaeC36:3, and PCaeC38:2 did not change significantly., Conclusions: The changes of glutamine, methionine, LPCaC18:1, LPCaC18:2, LPCa20:4, and PCaeC36:2 seem to be related to the changes of dieting or exercise habits in lifestyle intervention or to be a consequence of overweight since they normalized in weight loss. Further studies should substantiate our findings.

Background: The dopaminergic system is thought to be essentially involved in the pathogenesis of attention deficit/hyperactivity disorder (ADHD). However, there is also evidence for abnormalities in the glutamatergic system and recent theories focus on a disturbed interaction between the two systems as the essential pathogenetic mechanism of ADHD. In the present study, we wanted to test the hypothesis that prefrontal glutamate signals indirectly indicate dopaminergic dysfunction in adult patients with ADHD., Methods: Twenty-eight adult patients with ADHD and 28 group-matched healthy volunteers were studied clinically and using chemical-shift MR spectroscopy (MRS) of the prefrontal cortex covering the anterior cingulate gyrus., Results: A significant reduction of the combined glutamate/glutamine to creatine ratio in the right anterior cingulate cortex in patients with ADHD was found., Discussion: Glutamatergic alterations as measured with MRS might play a role in the pathogenesis of adult patients with ADHD.

The flux of inorganic and organic nitrogen into the mistletoe Viscum album L. from the xylem sap of a deciduous (Populus x euamericana) and a coniferous host (Abies alba Mill.) was analyzed. For this purpose, a perfusion system was developed in which the xylem sap of the host was replaced by an artificial perfusion solution. With this system flux rates into the mistletoe were determined in feeding experiments either with the organic nitrogen source [1,2-13C2]glutamine at high and the inorganic nitrogen source 15NO3- at low concentration or vice versa. Glutamine influx was already saturated at the low concentration in the xylem sap and was--different from nitrate--not enhanced, when a 250-fold higher concentration was applied. Nitrate influx matched glutamine influx only at high inorganic/organic nitrogen ratios in the perfusion solution. This result indicates a preferential influx of glutamine over nitrate from the host xylem into the mistletoe at the concentrations found in the xylem sap of trees. Surprisingly, a high percentage of both N sources were accumulated in the mistletoe stem, indicating excessive N nutrition of the mistletoe leaves. Since 13C isotope signature was significantly reduced in the outflowing perfusion solution, either an upload of organic compounds from the phloem into the xylem, or an efflux of organic compounds from haustorium of mistletoe into the xylem has to be assumed. 15N isotope signatures enriched in the outflowing perfusion solution support the idea of a nitrate uptake system at the host xylem-haustorium interface, which favors the light N isotope of nitrate.