Polyunsaturated fatty acids in the treatment of attention deficit hyperactivity disorder

Background: Attention deficit/hyperactivity disorder (ADHD) is one of the most common behavioral disorders in children. Insufficient dietary intake of long-chain polyunsaturated fatty acids (LC-PUFAs) has been suggested to have an impact on the development of symptoms of ADHD in children. Individuals with ADHD have been demonstrated to have significantly reduced blood concentrations of PUFAs and, in particular, reduced levels of omega-3 (n-3) PUFAs. These findings suggest that PUFA supplementation may reduce the attention and behavior problems associated with ADHD. Objective: To provide an overview of the efficacy of dietary LC-PUFA supplementation in the treatment of ADHD. Methods: Literature published up until December 2013 on the effects of n-3 PUFA supplementation on ADHD symptoms was obtained using a PubMed search and critically reviewed. Results: Dietary PUFA supplementation appears to have beneficial effects on ADHD symptoms although these effects are small. The clinical relevance of these observations remains to be determined. Conclusion: There is only limited support for the efficacy of PUFA supplementation for the core symptoms of ADHD. Given the small effect sizes regarding PUFA supplementation, it may not be a sufficient therapy for a majority of patients with ADHD

Single gene locus changes perturb complex microbial communities as much as apex predator loss

Many bacterial species are highly social, adaptively shaping their local environment through the production of secreted molecules. This can, in turn, alter interaction strengths among species and modify community composition. However, the relative importance of such behaviours in determining the structure of complex communities is unknown. Here we show that single-locus changes affecting biofilm formation phenotypes in Bacillus subtilis modify community structure to the same extent as loss of an apex predator and even to a greater extent than loss of B. subtilis itself. These results, from experimentally manipulated multitrophic microcosm assemblages, demonstrate that bacterial social traits are key modulators of the structure of their communities. Moreover, they show that intraspecific genetic variability can be as important as strong trophic interactions in determining community dynamics. Microevolution may therefore be as important as species extinctions in shaping the response of microbial communities to environmental change

Phospholipid bound to the flavohemoprotein from Alcaligenes eutrophus

The structurally characterized flavohemoprotein from Alcaligenes eutrophus (FHP) contains a phospholipid-binding site with 1-16 : 0-2-cyclo-17 : 0-diacyl-glycerophospho-ethanolamine and 1-16 : 0-2-cyclo-17 : 0-diacyl-glycerophospho-glycerol as the major occupying compounds. The structure of the phospholipid is characterized by its compact form, due to the -sc/beta/-sc conformation of the glycerol and the nonlinear arrangement of the sn-1- and sn-2-fatty acid chains. The phospholipid-binding site is located adjacent to the heme molecule at the bottom of a large cavity. The fatty acid chains form a large number of van der Waal's contacts with nonpolar side chains, whereas the glycerophosphate moiety, which points towards the entrance of the channel, is linked to the protein matrix by polar interactions. The thermodynamically stable globin module of FHP, obtained after cleaving off the oxidoreductase module, also contains the phospholipid and can therefore be considered as a phospholipid-binding protein. Single amino acid exchanges designed to decrease the lipid-binding site revealed both the possibility of blocking incorporation of the phospholipid and its capability to evade steric barriers. Conformational changes in the phospholipid can also be induced by binding heme-ligating compounds. Phospholipid binding is not a general feature of flavohemoproteins, because the Escherichia coli and the yeast protein exhibit less and no lipid affinity, respectively

Analysis of a putative voltage-gated prokaryotic potassium channel

Most of the completely sequenced prokaryotic genomes contain genes of potassium channel homologues, but there is still not much known about the role of these proteins in prokaryotes. Here we describe the large-scale overproduction and purification of a prokaryotic voltage-gated potassium channel homologue, Kch, from Escherichia coli. After successful overproduction of the protein, a specific increase in the potassium permeability of the cells was found. Kch could be purified in large amounts using classical purification methods to prevent aggregation of the protein. The physiological state of the protein was revealed to be a homotetramer and the protein was shown to be localized to the cytoplasmic membrane of the cells. In the course of the localization studies, we found a specific increase in the density of the cytoplasmic membrane on Kch production. This was linked to the observed increase in the protein to lipid ratio in the membranes. Another observed change in the membrane composition was an increase in the cardiolipin to phosphatidylglycerol ratio, which may indicate a specific cardiolipin requirement of Kch. On the basis of some of our results, we discuss a function for Kch in the maintenance of the membrane potential in E. coli

Benign childhood epilepsy with centrotemporal spikes and the multicomponent model of attention: a matched control study.

Although the high risk of cognitive impairments in benign childhood epilepsy with centrotemporal spikes (BCECTS) is now well established, there is no clear definition of a uniform neurocognitive profile. This study was based on a neuropsychological model of attention that assessed various components of attention in 21 children with BCECTS and 21 healthy children. All participants were tested with a computerized test battery using the multicomponent model of attention performance. In comparison with healthy participants, the children with BCECTS showed significant impairment in the measure of selectivity and in one measure of intensity of attention (arousal). Our results did not correlate with the electroclinical variables of age at onset of seizures and spike index on sleep EEGs. To the best of our knowledge, this is the first study in which the multicomponent model of attentional function has been used in children with BCECTS to provide a clearer neuropsychological profile of these patients. (C) 2010 Elsevier Inc. All rights reserved

Neurological soft signs are associated with attentional dysfunction in children with attention deficit hyperactivity disorder

Introduction: Inattention is one of the core symptoms of Attention Deficit Hyperactivity Disorder (ADHD). Most of patients with ADHD show motor impairment, consisting in the persistence of neurological soft signs (NSS). Our aim was to evaluate attentional and motor functioning in an ADHD sample and healthy children (HC) and possible link between attentional dysfunction and motor impairment in ADHD. Method: Twenty-seven drug-naive patients with ADHD and 23 HC were tested with a test battery, measuring different aspects of attention. Motor evaluation has provided three primary variables: overflow movements (OM), dysrhythmia and total speed of timed activities. Results: Compared to HC, patients were impaired in a considerable number of attentional processes and showed a greater number of NSS. Significant correlations between disturbances of attention and motor abnormalities were observed in ADHD group. Conclusion: Our findings suggest that attentional processes could be involved in the pathophysiology of the NSS and add scientific evidence to the predictive value of NSS as indicators of the severity of functional impairment in ADHD. Given the marked improvement or complete resolution of NSS following treatment with methylphenidate, we suggest that evaluation of NSS is useful to monitor the effectiveness of pharmacological treatment with MPH in ADHD