A systematic review of controlled trials of interventions to prevent childhood obesity and overweight: realistic synthesis of the evidence

Background: Preventing childhood overweight and obesity has become a major public health issue in developed and developing countries. Systematic reviews of this topic have not provided practice-relevant guidance because of the generally low quality of research and the heterogeneity of reported effectiveness. Aim: To present practice-relevant guidance on interventions to reduce at least one measure of adiposity in child populations that do or do not contain overweight or obese children. Design: Systematic review of eligible randomized, controlled trials or controlled trials using a novel approach to synthesizing the trial results through application of descriptive epidemiological and realistic evaluation concepts. Eligible trials involved at least 30 participants, lasted at least 12 weeks and involved non-clinical child populations. Results: Twenty-eight eligible trials were identified to 30 April 2006. Eleven trials were effective and 17 were ineffective in reducing adiposity. Blind to outcome, the main factor distinguishing effective from ineffective trials was the provision of moderate to vigorous aerobic physical activity in the former on a relatively 'compulsory' rather than 'voluntary' basis. Conclusions: By using a novel approach to synthesizing trials, a decisive role for the 'compulsory' provision of aerobic physical activity has been demonstrated. Further research is required to identify how such activity can be sustained and transformed into a personally chosen behaviour by children and over the life course. (C) 2007 The Royal Institute of Public Health. Published by Elsevier Ltd. All rights reserved.

Controlled variation of monomer sequence-distribution in the synthesis of aromatic poly(ether ketone)s

The effects of varying the alkali metal cation in the high-temperature nucleophilic synthesis of a semi-crystalline, aromatic poly(ether ketone) have been systematically investigated, and striking variations in the sequence-distributions and thermal characteristics of the resulting polymers were found. Polycondensation of 4,4'-dihydroxybenzophenone with 1,3-bis(4-fluorobenzoyl)benzene in diphenylsulfone as solvent, in the presence of an alkali metal carbonate M2CO3 (M= Li, Na, K, or Rb) as base, affords a range of different polymers that vary in the distribution pattern of 2-ring and 3-ring monomer units along the chain. Lithium carbonate gives an essentially alternating and highly crystalline polymer, but the degree of sequence-randomisation increases progressively as the alkali metal series is descended, with rubidium carbonate giving a fully random and non-thermally-crystallisable polymer. Randomisation during polycondensation is shown to result from reversible cleavage of the ether linkages in the polymer by fluoride ions, and an isolated sample of alternating-sequence polymer is thus converted to a fully randomised material on heating with rubidium fluoride.

Shape-controlled continuous synthesis of metal nanostructures

A segmented flow-based microreactor is used for the continuous production of faceted nanocrystals. Flow segmentation is proposed as a versatile tool to manipulate the reduction kinetics and control the growth of faceted nanostructures; tuning the size and shape. Switching the gas from oxygen to carbon monoxide permits the adjustment in nanostructure growth from 1D (nanorods) to 2D (nanosheets). CO is a key factor in the formation of Pd nanosheets and Pt nanocubes; operating as a second phase, a reductant, and a capping agent. This combination confines the growth to specific structures. In addition, the segmented flow microfluidic reactor inherently has the ability to operate in a reproducible manner at elevated temperatures and pressures whilst confining potentially toxic reactants, such as CO, in nanoliter slugs. This continuous system successfully synthesised Pd nanorods with an aspect ratio of 6; thin palladium nanosheets with a thickness of 1.5 nm; and Pt nanocubes with a 5.6 nm edge length, all in a synthesis time as low as 150 s.

Optimising the feedback loop of a millimetre-wave absolute photoacoustic power meter using H-infinity control synthesis

An H-infinity control strategy has been developed for the design of controllers used in feedback controlled electrical substitution measurements (FCESM). The methodology has the potential to provide substantial improvements in both response time and resolution of a millimetre-wave absolute photoacoustic power meter.

Roles of the translationally controlled tumour protein (TCTP) and the double-stranded RNA-dependent protein kinase, PKR, in cellular stress responses

Translationally controlled tumour protein (TCTP) is a highly conserved protein present in all eukaryotic organisms. Various cellular functions and molecular interactions have been ascribed to this protein, many related to its growth-promoting and antiapoptotic properties. TCTP levels are highly regulated in response to various cellular stimuli and stresses. We have shown recently that the double-stranded RNA-dependent protein kinase, PKR, is involved in translational regulation of TCTP. Here we extend these studies by demonstrating that TCTP is downregulated in response to various proapoptotic treatments, in particular agents that induce Ca++ stress, in a PKR-dependent manner. This regulation requires phosphorylation of protein synthesis factor eIF2α. Since TCTP has been characterized as an antiapoptotic and Ca++-binding protein, we asked whether it is involved in protecting cells from Ca++-stress-induced apoptosis. Overexpression of TCTP partially protects cells against thapsigargin-induced apoptosis, as measured using caspase-3 activation assays, a nuclear fragmentation assay, using fluorescence-activated cell sorting analysis, and time-lapse video microscopy. TCTP also protects cells against the proapoptotic effects of tunicamycin and etoposide, but not against those of arsenite. Our results imply that cellular TCTP levels influence sensitivity to apoptosis and that PKR may exert its proapoptotic effects at least in part through downregulation of TCTP via eIF2α phosphorylation.

Synthesis of beaded poly(vinyl ether) solid supports with unique solvent compatibility

Poly(vinyl ether) gels SLURPS (Superior Liquid Uptake Resin for Polymer-supported synthesis) with low cross-linking levels have been synthesized for the first time in beaded form using a non-aqueous inverse suspension polymerisation approach. The synthetic protocol was optimized with regards to several parameters including reactions conditions, type and concentration of suspension stabilizer and controlled low temperature addition of co-initiator. Particle size measurements confirm the production of beads with average diameters of 700e950 mm. Optimization of the monomer composition of the poly (vinyl ether) gels resulted in a novel beaded polymer support with considerably improved as well as unique swelling characteristics in solvents ranging from hexane to water. The synthetic utility of the new gel was confirmed by carrying out a set of transformations with complete conversion leading to a useful amino and hydroxy terminated solid-phase precursor resin. Reaction progress could be monitored easily by 1H and 13C gel-phase NMR.

Synthesis of mucoadhesive thiol-bearing microgels from 2-(acetylthio)ethylacrylate and 2-hydroxyethylmethacrylate: novel drug delivery systems for chemotherapeutic agents to the bladder

Thiol-bearing microgels have been synthesised from copolymerisation of 2-(acetylthio)ethylacrylate and 2-hydroxyethylmethacrylate, and subsequent deprotection using sodium thiomethoxide. The concentration of thiol groups on these microgels could be tailored by use of different molar ratios of the two monomers. These thiol-bearing microgels were shown to adhere to ex vivo porcine urinary bladder, which was correlated with their level of thiolation. By simply mixing solutions of thiol-bearing microgels and doxorubicin, high levels of drug loading into the microgels could be achieved. Thiol-bearing microgels controlled the release of doxorubicin in a time-dependent manner over several hours. These doxorubicin-loaded thiol-bearing microgels could have application in the treatment of early-stage bladder cancers. The method used represents a new ‘bottom-up’ approach for the synthesis of novel mucoadhesive microgels.