Child Overweight,Associated Psychopathology,and Social Functioning: A French School‐based Survey in 6‐ to 11‐year‐old Children

The aim of this study was to estimate the prevalence of child overweight in a regional sample of primary school‐aged children, and to examine the relationships among child overweight, psychopathology, and social functioning. A cross‐sectional survey was conducted in 2004 in 100 primary schools of a large French region, with 2,341 children aged 6–11 randomly selected. Child weight and height, lifestyle variables (leisure‐time physical activity (LTPA), watching television (TV), playing video games), and socioeconomic characteristics were collected in parent‐administered questionnaires. Child psychopathology outcomes were assessed using child‐ and parent‐reported instruments (Dominic Interactive (DI) and Strengths and Difficulties Questionnaire (SDQ)). Overweight and obesity were estimated according to the International Obesity Task Force (IOTF) definition. Response rates to the parent questionnaire and DI were 57.4 and 95.1%, respectively. Final sample size was 1,030 children. According to the IOTF, 17.3% of the children were overweight, of whom 3.3% were obese. In univariate analysis, correlates of overweight were low parental education, low monthly income, Disadvantaged School Areas (DSAs), self‐reported generalized anxiety, parent‐reported conduct disorders, emotional problems, and peer difficulties. High monthly income was less frequently associated with overweight. In multivariate analysis, parent‐reported peer difficulties (odds ratio (OR) = 2.06; 95% confidence interval = 1.27–3.35) and DSAs (1.88; 1.03–3.44) were independent factors significantly associated with child overweight. There was a trend of being overweight with elevated TV times (P for trend = 0.02). The psychosocial burden of excess weight appears to be significant even in young children. Findings should be considered for preventing strategies and public health interventions. School‐based overweight prevention programs should be implemented first in disadvantaged areas together with information about weight stigmatization and discrimination.     

Heparin modulation of human plasma kallikrein on different substrates and inhibitors

The interplay of different proteases and glycosaminoglycans is able to modulate the activity of the enzymes and to affect their structures. Human plasma kallikrein (huPK) is a proteolytic enzyme involved in intrinsic blood clotting, the kallikrein-kinin system and fibrinolysis. We investigated the effect of heparin on the action, inhibition and secondary structure of huPK. The catalytic efficiency for the hydrolysis of substrates by huPK was determined by Michaelis-Menten kinetic plots: 5.12x10(4) M-1 s-1 for acetyl-Phe-Arg-p-nitroanilide, 1.40x10(5) M-1 s-1 for H-D-Pro-Phe-Arg-p-nitroanilide, 2.25x10(4) M-1 s-1 for Abz-Gly-Phe-Ser-Pro-Phe-Arg-Ser-Ser-Arg-Gln-EDDnp, 4.24x10(2)M-1 s-1 for factor XII and 5.58x10(2) M-1 s-1 for plasminogen. Heparin reduced the hydrolysis of synthetic substrates (by 2.0-fold), but enhanced factor XII and plasminogen hydrolysis (7.7- and 1.4-fold, respectively). The second-order rate constants for inhibition of huPK by antithrombin and C1-inhibitor were 2.40x10(2) M-1 s-1 and 1.70x10(4) M-1 s-1, respectively. Heparin improved the inhibition of huPK by these inhibitors (3.4- and 1.4-fold). Despite the fact that huPK was able to bind to a heparin-Sepharose matrix, its secondary structure was not modified by heparin, as monitored by circular dichroism. These actions may have a function in the control or maintenance of some pathophysiological processes in which huPK participates.     

The membrane skeleton in Paramecium: Molecular characterization of a novel epiplasmin family and preliminary GFP expression results

Previous attempts to identify the membrane skeleton of Paramecium cells have revealed a protein pattern that is both complex and specific. The most prominent structural elements, epiplasmic scales, are centered around ciliary units and are closely apposed to the cytoplasmic side of the inner alveolar membrane. We sought to characterize epiplasmic scale proteins (epiplasmins) at the molecular level. PCR approaches enabled the cloning and sequencing of two closely related genes by amplifications of sequences from a macronuclear genomic library. Using these two genes (EPI-1 and EPI-2), we have contributed to the annotation of the Paramecium tetraurelia macronuclear genome and identified 39 additional (paralogous) sequences. Two orthologous sequences were found in the Tetrahymena thermophila genome. Structural analysis of the 43 sequences indicates that the hallmark of this new multigenic family is a 79 aa domain flanked by two Q-, P- and V-rich stretches of sequence that are much more variable in amino-acid composition. Such features clearly distinguish members of the multigenic family from epiplasmic proteins previously sequenced in other ciliates. The expression of Green Fluorescent Protein (GFP)-tagged epiplasmin showed significant labeling of epiplasmic scales as well as oral structures. We expect that the GFP construct described herein will prove to be a useful tool for comparative subcellular localization of different putative epiplasmins in Paramecium.     

Modulation of cell proliferation in rat liver cell cultures by new calix[4]arenes

Cell cycle progression is dependent on intracellular iron level and chelators lead to iron depletion and decrease cell proliferation. This antiproliferative effect can be inhibited by exogenous iron. In this work, we present the synthesis of new synthetic calix[4]arene podands bearing two aspartic/glutamic acid, ornithine groups or hydrazide function at the lower rim, designed as potential iron chelators. The synthesis only afforded calix[4]arenes in the cone conformation. We report their effect on cell proliferation, in comparison with the new oral chelator ICL670A (4-[3,5-bis-(2-hydroxyphenyl)-1,2,4-triazol-1-yl]-benzoic acid). The antiproliferative effect of these new compounds was studied in the rat hepatoma cell line Fao by measuring mitochondrial succinate dehydrogenase activity. Their cytotoxicity was evaluated by extracellular LDH activity. Preliminary results indicated that among all tested compounds, monohydrazidocalix[4]arene 2 which is not cytotoxic in Fao cells exhibits interesting antiproliferative activity. This effect, independent on iron depletion, remains to be further explored. Moreover, it also shows that new substituted calix[4]arenes could open the way to new valuable medicinal chemistry scaffolding.     

Biophysical characterization of Gir2, a highly acidic protein of Saccharomyces cerevisiae with anomalous electrophoretic behavior

Gir2 is an uncharacterized protein of Saccharomyces cerevisiae, containing a RWD/GI domain. In this work, we report the biophysical characterization of Gir2. His-tagged Gir2, expressed and purified from Escherichia coli, showed an abnormally slow migration on SDS-PAGE. The yeast expressed protein behaves similarly. Using mass spectrometry and peptide mass fingerprinting we demonstrated that the protein has the expected molecular mass (34kDa). EDC modification of carboxylate groups reverted the anomalous migration on SDS-PAGE. Size exclusion chromatography showed that Gir2 has a Stokes radius larger than expected. Gir2 is thermostable and lacks extensive structure, as determined by CD analysis. Based on these findings, we suggest that Gir2 is a representative of the growing group of "natively unfolded" proteins.     

Pancreatic vasopressin V1b receptors: characterization in In-R1-G9 cells and localization in human pancreas

Vasopressin (AVP) receptors present in In-R1-G9 cells, a hamster glucagon-secreting alpha-pancreatic cell line, were characterized using SSR-149415, a selective nonpeptide V1b receptor antagonist, and reference AVP compounds. Binding experiments, using [3H]AVP as a ligand, identified a single population of high-affinity binding sites. SSR-149415 competitively inhibited this binding and exhibited nanomolar and stereospecific affinity for these sites. The affinity of various AVP/oxytocin ligands confirmed a V1b binding profile. In functional studies, AVP was a potent stimulant in inducing intracellular Ca2+ increase, glucagon secretion, and cell proliferation. These effects were fully antagonized by SSR-149415 with a nanomolar potency, whereas its diasteroisomer as well as two selective V1a and V2 receptor antagonists were much less potent. Additionally, the order of potency of AVP agonists and antagonists was in agreement with V1b-mediated effects. By RT-PCR, we confirmed the presence of V1b receptor mRNA in both In-R1-G9 cells and in human pancreas. The distribution pattern of V1b receptors investigated in human pancreas by immunohistochemistry showed strong labeling in islets of Langerhans, and colocalization studies indicated that this receptor was expressed in alpha-glucagon, beta-insulin, and somatostatin pancreatic cells. Thus, in In-R1-G9 cells, AVP mediates intracellular Ca2+ increase, glucagon secretion, and cell proliferation by activating V1b receptors, and these effects are potently antagonized by SSR-149415. Moreover, the presence of V1b receptors also found in human Langerhans islets could suggest hormonal control of AVP in human pancreas.     

Efficient transposition of the Tnt1 tobacco retrotransposon in the model legume Medicago truncatula

The tobacco element, Tnt1, is one of the few active retrotransposons in plants. Its transposition is activated during protoplast culture in tobacco and tissue culture in the heterologous host Arabidopsis thaliana. Here, we report its transposition in the R108 line of Medicago truncatula during the early steps of the in vitro transformation-regeneration process. Two hundred and twenty-five primary transformants containing Tnt1 were obtained. Among them, 11.2% contained only transposed copies of the element, indicating that Tnt1 transposed very early and efficiently during the in vitro transformation process, possibly even before the T-DNA integration. The average number of insertions per transgenic line was estimated to be about 15. These insertions were stable in the progeny and could be separated by segregation. Inspection of the sequences flanking the insertion sites revealed that Tnt1 had no insertion site specificity and often inserted in genes (one out of three insertions). Thus, our work demonstrates the functioning of an efficient transposable element in leguminous plants. These results indicate that Tnt1 can be used as a powerful tool for insertion mutagenesis in M. truncatula.     

Contribution of APOA5 gene variants to plasma triglyceride determination and to the response to both fat and glucose tolerance challenges

The aim of this study was to investigate the influence of APOA5 variants on fasting lipids and to the response to both an oral fat tolerance test (OFTT) and an oral glucose tolerance test (OGTT). The association of two APOA5 SNPs [S19W (SNP5), -1131T>C (SNP3)] and an APOA4/A5 intergenic SNP [-12238T>C (SNP4)] were examined in healthy young men (n=774) who had undergone both an OFTT and an OGTT. Both -1131T>C and S19W rare alleles were associated with triglyceride (TG)-raising effects (11%, P=0.008; 21% (in cases), P<0.026, respectively) and showed additive effects on TG. None of the variants influenced the responsiveness to the OFTT after correcting for baseline TG. Homozygosity for the -12238T>C rare allele was associated with higher waist to hip ratio (P<0.0006), systolic blood pressure (P=0.012) and AUC and peak of insulin after OGTT (P=0.003 and P=0.027, respectively), traits that define the metabolic syndrome. Our results strongly support the role of APOA5 in determining plasma TG levels in an age-independent manner and highlight the importance of the APOC3/A4/A5 gene cluster in both TG and metabolic homeostasis.