Planning clinically relevant biomarker validation studies using the "number needed to treat" concept

Purpose: Despite an explosion of translational research to exploit biomarkers in diagnosis, prediction and prognosis, the impact of biomarkers on clinical practice has been limited. The elusiveness of clinical utility may partly originate when validation studies are planned, from a failure to articulate precisely how the biomarker, if successful, will improve clinical decision-making for patients. Clarifying what performance would suffice if the test is to improve medical care makes it possible to design meaningful validation studies. But methods for tackling this part of validation study design are undeveloped, because it demands uncomfortable judgments about the relative values of good and bad outcomes resulting from a medical decision. Methods: An unconventional use of "number needed to treat" (NNT) can structure communication for the trial design team, to elicit purely value-based outcome tradeoffs, conveyed as the endpoints of an NNT "discomfort range". The study biostatistician can convert the endpoints into desired predictive values, providing criteria for designing a prospective validation study. Next, a novel "contra-Bayes" theorem converts those predictive values into target sensitivity and specificity criteria, to guide design of a retrospective validation study. Several examples demonstrate the approach. Conclusion: In practice, NNT-guided dialogues have contributed to validation study planning by tying it closely to specific patient-oriented translational goals. The ultimate payoff comes when the report of the completed study includes motivation in the form of a biomarker test framework directly reflecting the clinical decision challenge to be solved. Then readers will understand better what the biomarker test has to offer patients

Assumptions about later life travel and their implications: pushing people around?

Taking four assumptions in turn, this review article considers some of the lenses through which researchers might look at later life leisure travel and the implications of adopting each of them. First, we consider the ‘active ageing’ agenda and what this means for how leisure travel may be thought about in academia and beyond. Second, we turn to studies underpinned by worries about the appetite for significant consumption thought to typify the ‘baby boomer’ generation and question whether these studies could inadvertently be promoting the very future they hope to avoid. Third, we explore how research on the benefits of everyday ‘mobility’ in later life may have morphed into a more general belief about the value of travel in older age. Finally, we reflect on how relevant studies of tourism are often underpinned by an argument about the financial rewards that now await those ready to target the older traveller. Our overall contention is that, though for different reasons, all four could be serving to encourage more later life travel. Whilst for some this prospect is not at all troubling, the spectre of adverse energy demand consequences leads us to explore a more critical view

A decision theory paradigm for evaluating identifier mapping and filtering methods using data integration.

In bioinformatics, we pre-process raw data into a format ready for answering medical and biological questions. A key step in processing is labeling the measured features with the identities of the molecules purportedly assayed: "molecular identification" (MI). Biological meaning comes from identifying these molecular measurements correctly with actual molecular species. But MI can be incorrect. Identifier filtering (IDF) selects features with more trusted MI, leaving a smaller, but more correct dataset. Identifier mapping (IDM) is needed when an analyst is combining two high-throughput (HT) measurement platforms on the same samples. IDM produces ID pairs, one ID from each platform, where the mapping declares that the two analytes are associated through a causal path, direct or indirect (example: pairing an ID for an mRNA species with an ID for a protein species that is its putative translation). Many competing solutions for IDF and IDM exist. Analysts need a rigorous method for evaluating and comparing all these choices. We describe a paradigm for critically evaluating and comparing IDF and IDM methods, guided by data on biological samples. The requirements are: a large set of biological samples, measurements on those samples from at least two high-throughput platforms, a model family connecting features from the platforms, and an association measure. From these ingredients, one fits a mixture model coupled to a decision framework. We demonstrate this evaluation paradigm in three settings: comparing performance of several bioinformatics resources for IDM between transcripts and proteins, comparing several published microarray probeset IDF methods and their combinations, and selecting optimal quality thresholds for tandem mass spectrometry spectral events. The paradigm outlined here provides a data-grounded approach for evaluating the quality not just of IDM and IDF, but of any pre-processing step or pipeline. The results will help researchers to semantically integrate or filter data optimally, and help bioinformatics database curators to track changes in quality over time and even to troubleshoot causes of MI errors

Organizational Stress in High-Level Field Hockey: Examining Transactional Pathways Between Stressors, Appraisals, Coping, and Performance Satisfaction

This study investigated transactional pathways between organizational stressors and their 28 underpinning situational properties, appraisals, coping, perceived coping effectiveness (PCE) 29 and performance satisfaction in athletes. Ten high-level field hockey players were 30 interviewed. Data relating to stressors, situational properties, appraisals and coping were 31 analysed using directed content analysis. Mean PCE scores were calculated and subjective 32 performance satisfaction data were categorised as satisfied, neutral, or dissatisfied. A variety 33 of organizational stressors was reported, which were underpinned by five situational 34 properties. Challenge, threat and harm/loss appraisals were experienced and problem solving 35 was the most commonly reported family of coping. High PCE was not always associated with 36 performance satisfaction. Performance satisfaction was, however, linked to the appraisal 37 experienced. A battery of stress management techniques and ways of coping is useful for 38 optimising appraisals and alleviating negative outcomes of stress

Duration of wrinkle correction following repeat treatment with Juvéderm hyaluronic acid fillers

Many patients elect to have repeat treatments with hyaluronic acid dermal fillers to maintain wrinkle correction, but the clinical performance of these products after repeat treatments has not been formally assessed. The primary objective of this study was to evaluate the effectiveness of Juvéderm injectable gel (Juvéderm Ultra, Juvéderm Ultra Plus, and Juvéderm 30) through 1 year after repeat treatment of nasolabial folds (NLFs) that were previously treated with Juvéderm or Zyplast 6–9 months prior to the repeat treatment. Upon completion of the pivotal IDE clinical trial for Juvéderm, five of the original 11 study sites were selected to participate in an extended follow-up evaluation, and a total of 80 subjects were enrolled. For the Juvéderm-treated NLFs in each treatment group, the median injection volume was 1.5–1.6 mL for initial treatment but only 0.5–0.6 mL for the repeat treatment (p < 0.0001). Mean Investigator-assigned NLF severity scores on a scale of 0–4 for the Juvéderm-treated NLFs improved from 2.5–2.7 (moderate to severe) at baseline to 1.2–1.5 (mild) just prior to repeat treatment (>24 weeks) and 0.7–0.9 (mild) at 4 weeks after repeat treatment. At 48 weeks post-repeat treatment, the mean NLF scores were 1.1–1.3 (mild), and 78–90% of subjects were considered responders (≥1 point improvement). Thus, subjects sustained a total of 18–21 months of wrinkle correction with a repeat treatment at 6–9 months and needed substantially less filler (60% less) for repeat treatment than for initial treatment, indicating that retreatment at this timepoint may be beneficial to patients

Reproductive Phase Locking of Mosquito Populations in Response to Rainfall Frequency

The frequency of moderate to heavy rainfall events is projected to change in response to global warming. Here we show that these hydrologic changes may have a profound effect on mosquito population dynamics and rates of mosquito-borne disease transmission. We develop a simple model, which treats the mosquito reproductive cycle as a phase oscillator that responds to rainfall frequency forcing. This model reproduces observed mosquito population dynamics and indicates that mosquito-borne disease transmission can be sensitive to rainfall frequency. These findings indicate that changes to the hydrologic cycle, in particular the frequency of moderate to heavy rainfall events, could have a profound effect on the transmission rates of some mosquito-borne diseases

The association between green space and cause-specific mortality in urban New Zealand: an ecological analysis of green space utility

&lt;b&gt;Background:&lt;/b&gt; There is mounting international evidence that exposure to green environments is associated with health benefits, including lower mortality rates. Consequently, it has been suggested that the uneven distribution of such environments may contribute to health inequalities. Possible causative mechanisms behind the green space and health relationship include the provision of physical activity opportunities, facilitation of social contact and the restorative effects of nature. In the New Zealand context we investigated whether there was a socioeconomic gradient in green space exposure and whether green space exposure was associated with cause-specific mortality (cardiovascular disease and lung cancer). We subsequently asked what is the mechanism(s) by which green space availability may influence mortality outcomes, by contrasting health associations for different types of green space. &lt;b&gt;Methods:&lt;/b&gt; This was an observational study on a population of 1,546,405 living in 1009 small urban areas in New Zealand. A neighbourhood-level classification was developed to distinguish between usable (i.e., visitable) and non-usable green space (i.e., visible but not visitable) in the urban areas. Negative binomial regression models were fitted to examine the association between quartiles of area-level green space availability and risk of mortality from cardiovascular disease (n = 9,484; 1996 - 2005) and from lung cancer (n = 2,603; 1996 - 2005), after control for age, sex, socio-economic deprivation, smoking, air pollution and population density. &lt;b&gt;Results:&lt;/b&gt; Deprived neighbourhoods were relatively disadvantaged in total green space availability (11% less total green space for a one standard deviation increase in NZDep2001 deprivation score, p &#60; 0.001), but had marginally more usable green space (2% more for a one standard deviation increase in deprivation score, p = 0.002). No significant associations between usable or total green space and mortality were observed after adjustment for confounders. &lt;b&gt;Conclusion&lt;/b&gt; Contrary to expectations we found no evidence that green space influenced cardiovascular disease mortality in New Zealand, suggesting that green space and health relationships may vary according to national, societal or environmental context. Hence we were unable to infer the mechanism in the relationship. Our inability to adjust for individual-level factors with a significant influence on cardiovascular disease and lung cancer mortality risk (e.g., diet and alcohol consumption) will have limited the ability of the analyses to detect green space effects, if present. Additionally, green space variation may have lesser relevance for health in New Zealand because green space is generally more abundant and there is less social and spatial variation in its availability than found in other contexts

Photocatalytic proton reduction by a computationally identified, molecular hydrogen-bonded framework

We show that a hydrogen-bonded framework, TBAP-α, with extended π-stacked pyrene columns has a sacrificial photocatalytic hydrogen production rate of up to 3108 μmol g^{−1} h^{−1}. This is the highest activity reported for a molecular organic crystal. By comparison, a chemically-identical but amorphous sample of TBAP was 20–200 times less active, depending on the reaction conditions, showing unambiguously that crystal packing in molecular crystals can dictate photocatalytic activity. Crystal structure prediction (CSP) was used to predict the solid-state structure of TBAP and other functionalised, conformationally-flexible pyrene derivatives. Specifically, we show that energy–structure–function (ESF) maps can be used to identify molecules such as TBAP that are likely to form extended π-stacked columns in the solid state. This opens up a methodology for the a priori computational design of molecular organic photocatalysts and other energy-relevant materials, such as organic electronics

A Prospective Longitudinal Study of the Clinical Outcomes from Cryptococcal Meningitis following Treatment Induction with 800 mg Oral Fluconazole in Blantyre, Malawi

Introduction: Cryptococcal meningitis is the most common neurological infection in HIV infected patients in Sub Saharan Africa, where gold standard treatment with intravenous amphotericin B and 5 flucytosine is often unavailable or difficult to administer. Fluconazole monotherapy is frequently recommended in national guidelines but is a fungistatic drug compromised by uncertainty over optimal dosing and a paucity of clinical end-point outcome data. Methods: From July 2010 until March 2011, HIV infected adults with a first episode of cryptococcal meningitis were recruited at Queen Elizabeth Central Hospital, Blantyre, Malawi. Patients were treated with oral fluconazole monotherapy 800 mg daily, as per national guidelines. ART was started at 4 weeks. Outcomes and factors associated with treatment failure were assessed 4, 10 and 52 weeks after fluconazole initiation. Results: Sixty patients were recruited. 26/60 (43%) died by 4 weeks. 35/60 (58.0%) and 43/56 (77%) died or failed treatment by 10 or 52 weeks respectively. Reduced consciousness (Glasgow Coma Score ,14 of 15), moderate/severe neurological disability (modified Rankin Score .3 of 5) and confusion (Abbreviated Mental Test Score ,8 of 10) were all common at baseline and associated with death or treatment failure. ART prior to recruitment was not associated with better outcomes. Conclusions: Mortality and treatment failure from cryptococcal meningitis following initiation of treatment with 800 mg oral fluconazole is unacceptably high. To improve outcomes, there is an urgent need for better therapeutic strategies and point-of-care diagnostics, allowing earlier diagnosis before development of neurological deficit

MiR-155 has a protective role in the development of non-alcoholic hepatosteatosis in mice

Hepatic steatosis is a global epidemic that is thought to contribute to the pathogenesis of type 2 diabetes. MicroRNAs (miRs) are regulators that can functionally integrate a range of metabolic and inflammatory pathways in liver. We aimed to investigate the functional role of miR-155 in hepatic steatosis. Male C57BL/6 wild-type (WT) and miR-155−/− mice were fed either normal chow or high fat diet (HFD) for 6 months then lipid levels, metabolic and inflammatory parameters were assessed in livers and serum of the mice. Mice lacking endogenous miR-155 that were fed HFD for 6 months developed increased hepatic steatosis compared to WT controls. This was associated with increased liver weight and serum VLDL/LDL cholesterol and alanine transaminase (ALT) levels, as well as increased hepatic expression of genes involved in glucose regulation (Pck1, Cebpa), fatty acid uptake (Cd36) and lipid metabolism (Fasn, Fabp4, Lpl, Abcd2, Pla2g7). Using miRNA target prediction algorithms and the microarray transcriptomic profile of miR-155−/− livers, we identified and validated that Nr1h3 (LXRα) as a direct miR-155 target gene that is potentially responsible for the liver phenotype of miR-155−/− mice. Together these data indicate that miR-155 plays a pivotal role regulating lipid metabolism in liver and that its deregulation may lead to hepatic steatosis in patients with diabetes