When is a randomised controlled trial health equity relevant? Development and validation of a conceptual framework.

BACKGROUND: Randomised controlled trials can provide evidence relevant to assessing the equity impact of an intervention, but such information is often poorly reported. We describe a conceptual framework to identify health equity-relevant randomised trials with the aim of improving the design and reporting of such trials. METHODS: An interdisciplinary and international research team engaged in an iterative consensus building process to develop and refine the conceptual framework via face-to-face meetings, teleconferences and email correspondence, including findings from a validation exercise whereby two independent reviewers used the emerging framework to classify a sample of randomised trials. RESULTS: A randomised trial can usefully be classified as 'health equity relevant' if it assesses the effects of an intervention on the health or its determinants of either individuals or a population who experience ill health due to disadvantage defined across one or more social determinants of health. Health equity-relevant randomised trials can either exclusively focus on a single population or collect data potentially useful for assessing differential effects of the intervention across multiple populations experiencing different levels or types of social disadvantage. Trials that are not classified as 'health equity relevant' may nevertheless provide information that is indirectly relevant to assessing equity impact, including information about individual level variation unrelated to social disadvantage and potentially useful in secondary modelling studies. CONCLUSION: The conceptual framework may be used to design and report randomised trials. The framework could also be used for other study designs to contribute to the evidence base for improved health equity.

Protocol for the development of a CONSORT-equity guideline to improve reporting of health equity in randomized trials.

BACKGROUND: Health equity concerns the absence of avoidable and unfair differences in health. Randomized controlled trials (RCTs) can provide evidence about the impact of an intervention on health equity for specific disadvantaged populations or in general populations; this is important for equity-focused decision-making. Previous work has identified a lack of adequate reporting guidelines for assessing health equity in RCTs. The objective of this study is to develop guidelines to improve the reporting of health equity considerations in RCTs, as an extension of the Consolidated Standards of Reporting Trials (CONSORT). METHODS/DESIGN: A six-phase study using integrated knowledge translation governed by a study executive and advisory board will assemble empirical evidence to inform the CONSORT-equity extension. To create the guideline, the following steps are proposed: (1) develop a conceptual framework for identifying "equity-relevant trials," (2) assess empirical evidence regarding reporting of equity-relevant trials, (3) consult with global methods and content experts on how to improve reporting of health equity in RCTs, (4) collect broad feedback and prioritize items needed to improve reporting of health equity in RCTs, (5) establish consensus on the CONSORT-equity extension: the guideline for equity-relevant trials, and (6) broadly disseminate and implement the CONSORT-equity extension. DISCUSSION: This work will be relevant to a broad range of RCTs addressing questions of effectiveness for strategies to improve practice and policy in the areas of social determinants of health, clinical care, health systems, public health, and international development, where health and/or access to health care is a primary outcome. The outcomes include a reporting guideline (CONSORT-equity extension) for equity-relevant RCTs and a knowledge translation strategy to broadly encourage its uptake and use by journal editors, authors, and funding agencies.

Modelling cell movement, cell differentiation, cell sorting and proportion regulation in Dictyostelium discoideum aggregations.

Understanding the mechanisms that control tissue morphogenesis and homeostasis is a central goal not only in developmental biology but also has great relevance for our understanding of various diseases, including cancer. A model organism that is widely used to study the control of tissue morphogenesis and proportioning is the Dictyostelium discoideum. While there are mathematical models describing the role of chemotactic cell motility in the Dictyostelium assembly and morphogenesis of multicellular tissues, as well as models addressing possible mechanisms of proportion regulation, there are no models incorporating both these key aspects of development. In this paper, we introduce a 1D hyperbolic model to investigate the role of two morphogens, DIF and cAMP, on cell movement, cell sorting, cell-type differentiation and proportioning in Dictyostelium discoideum. First, we use the non-spatial version of the model to study cell-type transdifferentiation. We perform a steady-state analysis of it and show that, depending on the shape of the differentiation rate functions, multiple steady-state solutions may occur. Then we incorporate spatial dynamics into the model, and investigate the transdifferentiation and spatial positioning of cells inside the newly formed structures, following the removal of prestalk or prespore regions of a Dictyostelium slug. We show that in isolated prespore fragments, a tipped mound-like aggregate can be formed after a transdifferentiation from prespore to prestalk cells and following the sorting of prestalk cells to the centre of the aggregate. For isolated prestalk fragments, we show the formation of a slug-like structure containing the usual anterior-posterior pattern of prestalk and prespore cells.

Alignment of an acoustic manipulation device with cepstral analysis of electronic impedance data.

Acoustic particle manipulation is an emerging technology that uses ultrasonic standing waves to position objects with pressure gradients and acoustic radiation forces. To produce strong standing waves, the transducer and the reflector must be aligned properly such that they are parallel to each other. This can be a difficult process due to the need to visualise the ultrasound waves and as higher frequencies are introduced, this alignment requires higher accuracy. In this paper, we present a method for aligning acoustic resonators with cepstral analysis. This is a simple signal processing technique that requires only the electrical impedance measurement data of the resonator, which is usually recorded during the fabrication process of the device. We first introduce the mathematical basis of cepstral analysis and then demonstrate and validate it using a computer simulation of an acoustic resonator. Finally, the technique is demonstrated experimentally to create many parallel linear traps for 10 µm fluorescent beads inside an acoustic resonator.

Impact of CONSORT extension for cluster randomised trials on quality of reporting and study methodology: review of random sample of 300 trials, 2000-8.

OBJECTIVE: To assess the impact of the 2004 extension of the CONSORT guidelines on the reporting and methodological quality of cluster randomised trials. DESIGN: Methodological review of 300 randomly sampled cluster randomised trials. Two reviewers independently abstracted 14 criteria related to quality of reporting and four methodological criteria specific to cluster randomised trials. We compared manuscripts published before CONSORT (2000-4) with those published after CONSORT (2005-8). We also investigated differences by journal impact factor, type of journal, and trial setting. DATA SOURCES: A validated Medline search strategy. Eligibility criteria for selecting studies Cluster randomised trials published in English language journals, 2000-8. RESULTS: There were significant improvements in five of 14 reporting criteria: identification as cluster randomised; justification for cluster randomisation; reporting whether outcome assessments were blind; reporting the number of clusters randomised; and reporting the number of clusters lost to follow-up. No significant improvements were found in adherence to methodological criteria. Trials conducted in clinical rather than non-clinical settings and studies published in medical journals with higher impact factor or general medical journals were more likely to adhere to recommended reporting and methodological criteria overall, but there was no evidence that improvements after publication of the CONSORT extension for cluster trials were more likely in trials conducted in clinical settings nor in trials published in either general medical journals or in higher impact factor journals. CONCLUSION: The quality of reporting of cluster randomised trials improved in only a few aspects since the publication of the extension of CONSORT for cluster randomised trials, and no improvements at all were observed in essential methodological features. Overall, the adherence to reporting and methodological guidelines for cluster randomised trials remains suboptimal, and further efforts are needed to improve both reporting and methodology.

Emergent cell and tissue dynamics from subcellular modeling of active biomechanical processes.

Cells and the tissues they form are not passive material bodies. Cells change their behavior in response to external biochemical and biomechanical cues. Behavioral changes, such as morphological deformation, proliferation and migration, are striking in many multicellular processes such as morphogenesis, wound healing and cancer progression. Cell-based modeling of these phenomena requires algorithms that can capture active cell behavior and their emergent tissue-level phenotypes. In this paper, we report on extensions of the subcellular element model to model active biomechanical subcellular processes. These processes lead to emergent cell and tissue level phenotypes at larger scales, including (i) adaptive shape deformations in cells responding to slow stretching, (ii) viscous flow of embryonic tissues, and (iii) streaming patterns of chemotactic cells in epithelial-like sheets. In each case, we connect our simulation results to recent experiments.

A 'chemotactic dipole' mechanism for large-scale vortex motion during primitive streak formation in the chick embryo.

Primitive streak formation in the chick embryo involves significant coordinated cell movement lateral to the streak, in addition to the posterior-anterior movement of cells in the streak proper. Cells lateral to the streak are observed to undergo 'polonaise movements', i.e. two large counter-rotating vortices, reminiscent of eddies in a fluid. In this paper, we propose a mechanism for these movement patterns which relies on chemotactic signals emitted by a dipolar configuration of cells in the posterior region of the epiblast. The 'chemotactic dipole' consists of adjacent regions of cells emitting chemo-attractants and chemo-repellents. We motivate this idea using a mathematical analogy between chemotaxis and electrostatics, and test this idea using large-scale computer simulations. We implement active cell response to both neighboring mechanical interactions and chemotactic gradients using the Subcellular Element Model. Simulations show the emergence of large-scale vortices of cell movement. The length and time scales of vortex formation are in reasonable agreement with experimental data. We also provide quantitative estimates for the robustness of the chemotaxis dipole mechanism, which indicate that the mechanism has an error tolerance of about 10% to variation in chemotactic parameters, assuming that only 1% of the cell population is involved in emitting signals. This tolerance increases for larger populations of cells emitting signals.

Suppression of cellular proliferation and invasion by the concerted lipid and protein phosphatase activities of PTEN.

PTEN is a tumour suppressor with phosphatase activity in vitro against both lipids and proteins and other potential non-enzymatic mechanisms of action. Although the importance of PTEN's lipid phosphatase activity in regulating the PI3K signalling pathway is recognized, the significance of PTEN's other mechanisms of action is currently unclear. In this study, we describe the systematic identification of a PTEN mutant, PTEN Y138L, with activity against lipid, but not soluble substrates. Using this mutant, we provide evidence for the interfacial activation of PTEN against lipid substrates. We also show that when re-expressed at physiological levels in PTEN null U87MG glioblastoma cells, the protein phosphatase activity of PTEN is not required to regulate cellular PtdInsP(3) levels or the downstream protein kinase Akt/PKB. Finally, in three-dimensional Matrigel cultures of U87MG cells similarly re-expressing PTEN mutants, both the protein and lipid phosphatase activities were required to inhibit invasion, but either activity alone significantly inhibited proliferation, albeit only weakly for the protein phosphatase activity. Our data provide a novel tool to address the significance of PTEN's separable lipid and protein phosphatase activities and suggest that both activities suppress proliferation and together suppress invasion.

A comparison of journal instructions regarding institutional review board approval and conflict-of-interest disclosure between 1995 and 2005.

OBJECTIVES: To compare 2005 and 1995 ethics guidelines from journal editors to authors regarding requirements for institutional review board (IRB) approval and conflict-of-interest (COI) disclosure. DESIGN: A descriptive study of the ethics guidelines published in 103 English-language biomedical journals listed in the Abridged Index Medicus in 1995 and 2005. Each journal was reviewed by the principal author and one of four independent reviewers. RESULTS: During the period, the proportion of journals requiring IRB approval increased from 42% (95% CI 32.2% to 51.2%, p<0.001) to 76% (95% CI 66.4% to 83.1%, p<0.001). In 2005, an additional 9% referred to the Declaration of Helsinki or the International Committee of Medical Journal Editors' Uniform requirements for ethical guidelines; 15% (95% CI 8.5% to 22.5%, p<0.01) provided ambiguous or no requirements. The proportion of journals requiring COI disclosure increased from 75% (95% CI 66.6% to 83.3%, p<0.05) to 94% (95% CI 89.4% to 98.6%, p<0.05); 41% had comprehensive requirements, while some addressed only funding source (6%), were vague (10%) or both (14%). Criteria for authorship rose from 40% (95% CI 30.5% to 49.5%, p<0.05) to 72% (95% CI 63.3% to 80.7%, p<0.05). Journals with higher impact factors were more likely to require IRB approval (p<0.01). Journals in anaesthesia and radiology all required IRB approval; requirements in other disciplines varied. CONCLUSIONS: Instructions to authors regarding ethical standards have improved. Some remain incomplete, especially regarding the scope of disclosure of COI. The ethical guidelines presented to authors need further clarification and standardisation.

Refuting the net risks test: a response to Wendler and Miller's "Assessing research risks systematically".

Earlier in the pages of this journal (p 481), Wendler and Miller offered the "net risks test" as an alternative approach to the ethical analysis of benefits and harms in research. They have been vocal critics of the dominant view of benefit-harm analysis in research ethics, which encompasses core concepts of duty of care, clinical equipoise and component analysis. They had been challenged to come up with a viable alternative to component analysis which meets five criteria. The alternative must (1) protect research subjects; (2) allow clinical research to proceed; (3) explain how physicians may offer trial enrolment to their patients; (4) address the challenges posed by research containing a mixture of interventions and (5) define ethical standards according to which the risks and potential benefits of research may be consistently evaluated. This response argues that the net risks test meets none of these criteria and concludes that it is not a viable alternative to component analysis.

The return of research results to participants: pilot questionnaire of adolescents and parents of children with cancer.

PURPOSE: The offer to return research results to participants is increasingly recognized as an ethical obligation, although few researchers routinely return results. We examined the needs and attitudes of parents of children with cancer and of adolescents with cancer to the return of research results. METHODS: Seven experts in research ethics scored content validity on parent and adolescent questionnaires previously developed through focus group and phone interviews. The questionnaires were revised and provided to 30 parents and 10 adolescents in a tertiary care oncology setting. RESULTS: The content validity index for individual questions and the overall questionnaires scored as 0.86 for both questionnaires. All 30 parents and 10 adolescents who agreed to participate returned questionnaires. The majority (>95%) indicated that they had a strong or very strong right to receive results. Letter or e-mail was a satisfactory means to return results described as good or neutral (66% parents, 100% adolescents) but more participants wished face-to-face disclosure of results with negative implications (50% parents, 60% adolescents). Very few wanted results disseminated through a Web site. The majority acknowledged the need for peer-review before disclosure (60% of adolescents and parents) but did not want "to be the last to know." CONCLUSIONS: Our data suggest that pediatric oncology patients and parents of children with cancer strongly feel that they have a right to research results, and that they wish to receive these in a timely manner.

Trust based obligations of the state and physician-researchers to patient-subjects.

When may a physician enroll a patient in clinical research? An adequate answer to this question requires clarification of trust-based obligations of the state and the physician-researcher respectively to the patient-subject. The state relies on the voluntarism of patient-subjects to advance the public interest in science. Accordingly, it is obligated to protect the agent-neutral interests of patient-subjects through promulgating standards that secure these interests. Component analysis is the only comprehensive and systematic specification of regulatory standards for benefit-harm evaluation by research ethics committees (RECs). Clinical equipoise, a standard in component analysis, ensures the treatment arms of a randomised control trial are consistent with competent medical care. It thus serves to protect agent-neutral welfare interests of the patient-subject. But REC review occurs prior to enrolment, highlighting the independent responsibility of the physician-researcher to protect the agent-relative welfare interests of the patient-subject. In a novel interpretation of the duty of care, we argue for a "clinical judgment principle" which requires the physician-researcher to exercise judgment in the interests of the patient-subject taking into account evidence on treatments and the patient-subject's circumstances.

The regulation of cell migration by PTEN.

In vertebrates, the tumour suppressor PTEN (phosphatase and tensin homologue deleted on chromosome 10) regulates many cellular processes through its PtdIns(3,4,5)P3 lipid phosphatase activity, antagonizing PI3K (phosphoinositide 3-kinase) signalling. Given the important role of PI3Ks in the regulation of directed cell migration and the role of PTEN as an inhibitor of migration, it is somewhat surprising that data now indicate that PTEN is able to regulate cell migration independent of its lipid phosphatase activity. Here, we discuss the role of PTEN in the regulation of cell migration.

Protecting communities in pharmacogenetic and pharmacogenomic research.

The existing EELS literature has usefully identified the scope of ethical issues posed by pharmacogenetic and pharmacogenomic research. The time has come for in-depth examination of particular ethical issues. The involvement of racial and ethnic communities in pharmacogenetic and pharmacogenomic research is contentious precisely because it touches upon the science and politics of studying racial and ethnic difference. To date, the ethics literature has not seriously taken account of the fact that such research impinges upon the interests of communities, and that taking such interests seriously requires that we both protect and empower communities in research. We propose a framework that rests upon the recognition that communities are heterogeneous human associations and differing policies are appropriate for differing communities. Community consent and consultation and community consultation alone are neither appropriate nor required for all pharmacogenetic and pharmacogenomic research. Rather, application of these policy protections must take into account particulars of both planned research and the communities involved.

Becoming Multicellular by Aggregation; The Morphogenesis of the Social Amoebae Dicyostelium discoideum.

The organisation and form of most organisms is generated during theirembryonic development and involves precise spatial and temporal controlof cell division, cell death, cell differentiation and cell movement.Differential cell movement is a particularly important mechanism in thegeneration of form. Arguably the best understood mechanism of directedmovement is chemotaxis. Chemotaxis plays a major role in the starvationinduced multicellular development of the social amoebae Dictyostelium.Upon starvation up to 10(5) individual amoebae aggregate to form afruiting body. In this paper we review the evidence that the movement ofthe cells during all stages of Dictyostelium development is controlled bypropagating waves of cAMP which control the chemotactic movement ofthe cells. We analyse the complex interactions between cell-cell signallingresulting in cAMP waves of various geometries and cell movement whichresults in a redistribution of the signalling sources and therefore changes thegeometry of the waves. We proceed to show how the morphogenesis,including aggregation stream and mound formation, slug formation andmigration, of this relatively simple organism is beginning to be understoodat the level of rules for cell behaviour, which can be tested experimentallyand theoretically by model calculations.

A Dictyostelium nuclear phosphatidylinositol phosphate kinase required for developmental gene expression.

The generation of diacylglycerol (DAG) in response to receptor stimulation is a well-documented signalling mechanism that leads to activation of protein kinase C (PKC). Putative alternative effectors contain sequences that interact with DAGs, but the mechanisms of signal transduction are unknown. We have identified a Dictyostelium gene encoding a novel protein which contains a domain with high identity to the DAG-binding domain of PKC. It does not encode a PKC homologue as the conservation does not extend outside this region. We confirm that the proposed DAG-binding domain is sufficient to mediate interaction of a fusion protein with vesicles containing DAG. The protein also shows significant homology to mammalian phosphatidylinositol phosphate (PIP) kinases and we show that this domain has PIP kinase activity. The protein, PIPkinA, is enriched in the nucleus and abrogation of gene function by homologous recombination inhibits early developmental gene expression, blocking development at an early stage. Thus, we have identified a PIP kinase from Dictyostelium which is required for development, is a candidate effector for DAG and has the potential to synthesize nuclear PIP(2).

Propagating chemoattractant waves coordinate periodic cell movement in Dictyostelium slugs.

Migration and behaviour of Dictyostelium slugs results from coordinated movement of its constituent cells. It has been proposed that cell movement is controlled by propagating waves of cAMP as during aggregation and in the mound. We report the existence of optical density waves in slugs; they are initiated in the tip and propagate backwards. The waves reflect periodic cell movement and are mediated by cAMP, as injection of cAMP or cAMP phosphodiesterase disrupts wave propagation and results in effects on cell movement and, therefore, slug migration. Inhibiting the function of the cAMP receptor cAR1 blocks wave propagation, showing that the signal is mediated by cAR1. Wave initiation is strictly dependent on the tip; in decapitated slugs no new waves are initiated and slug movement stops until a new tip regenerates. Isolated tips continue to migrate while producing waves. We conclude from these observations that the tip acts as a pacemaker for cAMP waves that coordinate cell movement in slugs.

cAMP receptor affinity controls wave dynamics, geometry and morphogenesis in Dictyostelium.

Serpentine G-protein-coupled cAMP receptors are key components in the detection and relay of the extracellular cAMP waves that control chemotactic cell movement during Dictyostelium development. During development the cells sequentially express four closely related cAMP receptors of decreasing affinity. In this study, we investigated the effect of cAMP receptor type and affinity on the dynamics of cell-cell signalling in vivo, by measuring the dynamics of wave initiation and propagation in a variety of cAMP receptor mutants. We found that receptor affinity controls the frequency of wave initiation, but it does not determine wave propagation velocity, thus resulting in dramatic changes in wave geometry. In the limiting case, the affinity of the receptor is so low that waves can still be initiated but no stable centres form - thus, the cells cannot aggregate. In mounds, expression of low affinity receptors results in slow concentric waves instead of the normally observed multi-armed spiral waves. Under these conditions there is no rotational cell movement and the hemispherical mounds cannot transform into slugs. These results highlight the importance of receptor number and affinity in the proper control of cell-cell signalling dynamics required for the successful completion of development.

The ethics wars. Disputes over international research.

The effort to revise the Declaration of Helsinki and the CIOMS Guidelines has sparked a sometimes vitriolic debate centering on the use of placebo controls.