Can Research Assessments Themselves Cause Bias in Behaviour Change Trials? A Systematic Review of Evidence from Solomon 4-Group Studies

BACKGROUND: The possible effects of research assessments on participant behaviour have attracted research interest, especially in studies with behavioural interventions and/or outcomes. Assessments may introduce bias in randomised controlled trials by altering receptivity to intervention in experimental groups and differentially impacting on the behaviour of control groups. In a Solomon 4-group design, participants are randomly allocated to one of four arms: (1) assessed experimental group; (2) unassessed experimental group (3) assessed control group; or (4) unassessed control group. This design provides a test of the internal validity of effect sizes obtained in conventional two-group trials by controlling for the effects of baseline assessment, and assessing interactions between the intervention and baseline assessment. The aim of this systematic review is to evaluate evidence from Solomon 4-group studies with behavioural outcomes that baseline research assessments themselves can introduce bias into trials. METHODOLOGY/PRINCIPAL FINDINGS: Electronic databases were searched, supplemented by citation searching. Studies were eligible if they reported appropriately analysed results in peer-reviewed journals and used Solomon 4-group designs in non-laboratory settings with behavioural outcome measures and sample sizes of 20 per group or greater. Ten studies from a range of applied areas were included. There was inconsistent evidence of main effects of assessment, sparse evidence of interactions with behavioural interventions, and a lack of convincing data in relation to the research question for this review. CONCLUSIONS/SIGNIFICANCE: There were too few high quality completed studies to infer conclusively that biases stemming from baseline research assessments do or do not exist. There is, therefore a need for new rigorous Solomon 4-group studies that are purposively designed to evaluate the potential for research assessments to cause bias in behaviour change trials

Identification of gene co-regulatory modules and associated cis-elements involved in degenerative heart disease

<p>Abstract</p> <p>Background</p> <p>Cardiomyopathies, degenerative diseases of cardiac muscle, are among the leading causes of death in the developed world. Microarray studies of cardiomyopathies have identified up to several hundred genes that significantly alter their expression patterns as the disease progresses. However, the regulatory mechanisms driving these changes, in particular the networks of transcription factors involved, remain poorly understood. Our goals are (A) to identify modules of co-regulated genes that undergo similar changes in expression in various types of cardiomyopathies, and (B) to reveal the specific pattern of transcription factor binding sites, <it>cis</it>-elements, in the proximal promoter region of genes comprising such modules.</p> <p>Methods</p> <p>We analyzed 149 microarray samples from human hypertrophic and dilated cardiomyopathies of various etiologies. Hierarchical clustering and Gene Ontology annotations were applied to identify modules enriched in genes with highly correlated expression and a similar physiological function. To discover motifs that may underly changes in expression, we used the promoter regions for genes in three of the most interesting modules as input to motif discovery algorithms. The resulting motifs were used to construct a probabilistic model predictive of changes in expression across different cardiomyopathies.</p> <p>Results</p> <p>We found that three modules with the highest degree of functional enrichment contain genes involved in myocardial contraction (n = 9), energy generation (n = 20), or protein translation (n = 20). Using motif discovery tools revealed that genes in the contractile module were found to contain a TATA-box followed by a CACC-box, and are depleted in other GC-rich motifs; whereas genes in the translation module contain a pyrimidine-rich initiator, Elk-1, SP-1, and a novel motif with a GCGC core. Using a naïve Bayes classifier revealed that patterns of motifs are statistically predictive of expression patterns, with odds ratios of 2.7 (contractile), 1.9 (energy generation), and 5.5 (protein translation).</p> <p>Conclusion</p> <p>We identified patterns comprised of putative <it>cis</it>-regulatory motifs enriched in the upstream promoter sequence of genes that undergo similar changes in expression secondary to cardiomyopathies of various etiologies. Our analysis is a first step towards understanding transcription factor networks that are active in regulating gene expression during degenerative heart disease.</p

A Bacterial Acetyltransferase Destroys Plant Microtubule Networks and Blocks Secretion

The eukaryotic cytoskeleton is essential for structural support and intracellular transport, and is therefore a common target of animal pathogens. However, no phytopathogenic effector has yet been demonstrated to specifically target the plant cytoskeleton. Here we show that the Pseudomonas syringae type III secreted effector HopZ1a interacts with tubulin and polymerized microtubules. We demonstrate that HopZ1a is an acetyltransferase activated by the eukaryotic co-factor phytic acid. Activated HopZ1a acetylates itself and tubulin. The conserved autoacetylation site of the YopJ / HopZ superfamily, K289, plays a critical role in both the avirulence and virulence function of HopZ1a. Furthermore, HopZ1a requires its acetyltransferase activity to cause a dramatic decrease in Arabidopsis thaliana microtubule networks, disrupt the plant secretory pathway and suppress cell wall-mediated defense. Together, this study supports the hypothesis that HopZ1a promotes virulence through cytoskeletal and secretory disruption

Glucocorticoid suppression of CX<inf>3</inf>CL1 (fractalkine) by reduced gene promoter recruitment of NF-κB

Glucocorticoids are an important anti-inflammatory treatment of many inflammatory diseases including asthma. However, the mechanisms by which they mediate their suppressive effects are not fully understood. Respiratory epithelial cells are a source of CX3CL1 (fractalkine), which mediates cell adhesion and acts as a chemoattractant for monocytes, T cells, and mast cells. We show, in lung A549 epithelial cells, that the tumor necrosis factor-α (TNF-α) and IFNγ synergistically induced protein release and mRNA expression of CX3CL1 is inhibited by dexamethasone, without interfering with cytokine-induced nuclear translocation of NF-κB, and by an inhibitor of IκB kinase 2, AS602868. DNA binding assays confirmed the ability of NF-κB to bind to the proximal CX3CL1 promoter. Chromatin immunoprecipitation assays showed a 5-fold increase in the recruitment of NF-κB to the CX3CL1 gene promoter in response to IFNγ/TNF-α; this too was reversed by dexamethasone. In contrast, dexamethasone did not displace NF-κB from the granulocyte-macrophage colony-stimulating factor gene promoter. We conclude that CX3CL1 expression is regulated through the NF-κB pathway and that dexamethasone inhibits CX3CL1 expression through a glucocorticoid receptor-dependent (RU486 sensitive) mechanism. This study also provides support for the action of glucocorticoids mediating their suppressive effects on expression by interfering with the binding of transcriptional activators at native gene promoters. © FASEB

GRO-α regulation in airway smooth muscle by IL-1β and TNF-α: Role of NF-κB and MAP kinases

Airway smooth muscle cells (ASMC) are a source of inflammatory chemokines that may propagate airway inflammatory responses. We investigated the production of the CXC chemokine growth-related oncogene protein-α (GRO-α) from ASMC induced by cytokines and the role of MAPK and NF-κB pathways. ASMC were cultured from human airways, grown to confluence, and exposed to cytokines IL-1β and TNF-α after growth arrest. GRO-α release, measured by ELISA, was increased by >50-fold after IL-1β (0.1 ng/ml) or 5-fold after TNF-α (1 ng/ml) in a dose- and time-dependent manner. GRO-α release was not affected by the T helper type 2 cytokines IL-4, IL-10, and IL-13. IL-1β and TNF-α also induced GRO-α mRNA expression. Supernatants from IL-1β-stimulated ASMC were chemotactic for neutrophils; this effect was inhibited by anti-GRO-α blocking antibody. AS-602868, an inhibitor of IKK-2, and PD-98059, an inhibitor of ERK, inhibited GRO-α release and mRNA expression, whereas SP-600125, an inhibitor of JNK, reduced GRO-α release without effect on mRNA expression. SB-203580, an inhibitor of p38 MAPK, had no effect. AS-602868 but not PD-98059 or SP-600125 inhibited p65 DNA-binding induced by IL-1β and TNF-α. By chromatin immunoprecipitation assay, IL-1β and TNF-α enhanced p65 binding to the GRO-α promoter, which was inhibited by AS-602868. IL-1β- and TNF-α-stimulated expression of GRO-α from ASMC is regulated by independent pathways involving NF-κB activation and ERK and JNK pathways. GRO-α released from ASMC participates in neutrophil chemotaxis. Copyright © 2006 the American Physiological Society