Development and evaluation of a diagnostic cytokine-release assay for Mycobacterium suricattae infection in meerkats (Suricata suricatta)

CITATION: Clarke, C., et al. 2017. Development and evaluation of a diagnostic cytokine-release assay for mycobacterium suricattae infection in meerkats (Suricata suricatta). BMC Veterinary Research, 13:2, doi:10.1186/s12917-016-0927-x.The original publication is available at http://bmcvetres.biomedcentral.comBackground: Sensitive diagnostic tools are necessary for the detection of Mycobacterium suricattae infection in meerkats (Suricata suricatta) in order to more clearly understand the epidemiology of tuberculosis and the ecological consequences of the disease in this species. We therefore aimed to develop a cytokine release assay to measure antigen-specific cell-mediated immune responses of meerkats. Results: Enzyme-linked immunosorbent assays (ELISAs) were evaluated for the detection of interferon-gamma (IFN-γ) and IFN-γ inducible protein 10 (IP-10) in meerkat plasma. An IP-10 ELISA was selected to measure the release of this cytokine in whole blood in response to Bovigam® PC-HP Stimulating Antigen, a commercial peptide pool of M. bovis antigens. Using this protocol, captive meerkats with no known M. suricattae exposure (n = 10) were tested and results were used to define a diagnostic cut off value (mean plus 2 standard deviations). This IP-10 release assay (IPRA) was then evaluated in free-living meerkats with known M. suricattae exposure, categorized as having either a low, moderate or high risk of infection with this pathogen. In each category, respectively, 24.7%, 27.3% and 82.4% of animals tested IPRA-positive. The odds of an animal testing positive was 14.0 times greater for animals with a high risk of M. suricattae infection compared to animals with a low risk. Conclusion: These results support the use of this assay as a measure of M. suricattae exposure in meerkat populations. Ongoing longitudinal studies aim to evaluate the value of the IPRA as a diagnostic test of M. suricattae infection in individual animals.http://bmcvetres.biomedcentral.com/articles/10.1186/s12917-016-0927-xPublisher's versio

A study protocol to investigate the management of depression and challenging behaviors associated with dementia in aged care settings

Background:&nbsp;The high occurrence and under-treatment of clinical depression and behavioral and psychological symptoms of dementia (BPSD) within aged care settings is concerning, yet training programs aimed at improving the detection and management of these problems have generally been ineffective. This article presents a study protocol to evaluate a training intervention for facility managers/registered nurses working in aged care facilities that focuses on organisational processes and culture as well as knowledge, skills and self-efficacy. Methods. A Randomised Control Trial (RCT) will be implemented across 18 aged care facilities (divided into three conditions). Participants will be senior registered nurses and personal care attendants employed in the aged care facility. The first condition will receive the training program (Staff as Change Agents - Enhancing and Sustaining Mental Health in Aged Care), the second condition will receive the training program and clinical support, and the third condition will receive no intervention. Results: Pre-, post-, 6-month and 12-month follow-up measures of staff and residents will be used to demonstrate how upskilling clinical leaders using our transformational training approach, as well as the use of a structured screening, referral and monitoring protocol, can address the mental health needs of older people in residential care. Conclusions: The expected outcome of this study is the validation of an evidence-based training program to improve the management of depression and BPSD among older people in residential care settings by establishing routine practices related to mental health. This relatively brief but highly focussed training package will be readily rolled out to a larger number of residential care facilities at a relatively low cost.</div

SUP: an extension to SLINK to allow a larger number of marker loci to be simulated in pedigrees conditional on trait values

BACKGROUND: With the recent advances in high-throughput genotyping technologies that allow for large-scale association mapping of human complex traits, promising statistical designs and methods have been emerging. Efficient simulation software are key elements for the evaluation of the properties of new statistical tests. SLINK is a flexible simulation tool that has been widely used to generate the segregation and recombination processes of markers linked to, and possibly associated with, a trait locus, conditional on trait values in arbitrary pedigrees. In practice, its most serious limitation is the small number of loci that can be simulated, since the complexity of the algorithm scales exponentially with this number. RESULTS: I describe the implementation of a two-step algorithm to be used in conjunction with SLINK to enable the simulation of a large number of marker loci linked to a trait locus and conditional on trait values in families, with the possibility for the loci to be in linkage disequilibrium. SLINK is used in the first step to simulate genotypes at the trait locus conditional on the observed trait values, and also to generate an indicator of the descent path of the simulated alleles. In the second step, marker alleles or haplotypes are generated in the founders, conditional on the trait locus genotypes simulated in the first step. Then the recombination process between the marker loci takes place conditionally on the descent path and on the trait locus genotypes. This two-step implementation is often computationally faster than other software that are designed to generate marker data linked to, and possibly associated with, a trait locus. CONCLUSION: Because the proposed method uses SLINK to simulate the segregation process, it benefits from its flexibility: the trait may be qualitative with the possibility of defining different liability classes (which allows for the simulation of gene-environment interactions or even the simulation of multi-locus effects between unlinked susceptibility regions) or it may be quantitative and normally distributed. In particular, this implementation is the only one available that can generate a large number of marker loci conditional on the set of observed quantitative trait values in pedigrees

Subtropical grass pollen allergens are important for allergic respiratory diseases in subtropical regions

Background: Grass pollen allergens are a major cause of allergic respiratory disease but traditionally prescribing practice for grass pollen allergen-specific immunotherapy has favoured pollen extracts of temperate grasses. Here we aim to compare allergy to subtropical and temperate grass pollens in patients with allergic rhinitis from a subtropical region of Australia. Methods. Sensitization to pollen extracts of the subtropical Bahia grass (Paspalum notatum), Johnson grass (Sorghum halepense) and Bermuda grass (Cynodon dactylon) as well as the temperate Ryegrass (Lolium perenne) were measured by skin prick in 233 subjects from Brisbane. Grass pollen-specific IgE reactivity was tested by ELISA and cross-inhibition ELISA. Results: Patients with grass pollen allergy from a subtropical region showed higher skin prick diameters with subtropical Bahia grass and Bermuda grass pollens than with Johnson grass and Ryegrass pollens. IgE reactivity was higher with pollen of Bahia grass than Bermuda grass, Johnson grass and Ryegrass. Patients showed asymmetric cross-inhibition of IgE reactivity with subtropical grass pollens that was not blocked by temperate grass pollen allergens indicating the presence of species-specific IgE binding sites of subtropical grass pollen allergens that are not represented in temperate grass pollens. Conclusions: Subtropical grass pollens are more important allergen sources than temperate grass pollens for patients from a subtropical region. Targeting allergen-specific immunotherapy to subtropical grass pollen allergens in patients with allergic rhinitis in subtropical regions could improve treatment efficacy thereby reducing the burden of allergic rhinitis and asthma

Genetic Association Analysis Using Sibship Data: A Multilevel Model Approach

Family based association study (FBAS) has the advantages of controlling for population stratification and testing for linkage and association simultaneously. We propose a retrospective multilevel model (rMLM) approach to analyze sibship data by using genotypic information as the dependent variable. Simulated data sets were generated using the simulation of linkage and association (SIMLA) program. We compared rMLM to sib transmission/disequilibrium test (S-TDT), sibling disequilibrium test (SDT), conditional logistic regression (CLR) and generalized estimation equations (GEE) on the measures of power, type I error, estimation bias and standard error. The results indicated that rMLM was a valid test of association in the presence of linkage using sibship data. The advantages of rMLM became more evident when the data contained concordant sibships. Compared to GEE, rMLM had less underestimated odds ratio (OR). Our results support the application of rMLM to detect gene-disease associations using sibship data. However, the risk of increasing type I error rate should be cautioned when there is association without linkage between the disease locus and the genotyped marker

CRTC Potentiates Light-independent timeless Transcription to Sustain Circadian Rhythms in Drosophila

Light is one of the strongest environmental time cues for entraining endogenous circadian rhythms. Emerging evidence indicates that CREB-regulated transcription co-activator 1 (CRTC1) is a key player in this pathway, stimulating light-induced Period1 (Per1) transcription in mammalian clocks. Here, we demonstrate a light-independent role of Drosophila CRTC in sustaining circadian behaviors. Genomic deletion of the crtc locus causes long but poor locomotor rhythms in constant darkness. Overexpression or RNA interference-mediated depletion of CRTC in circadian pacemaker neurons similarly impairs the free-running behavioral rhythms, implying that Drosophila clocks are sensitive to the dosage of CRTC. The crtc null mutation delays the overall phase of circadian gene expression yet it remarkably dampens light-independent oscillations of TIMELESS (TIM) proteins in the clock neurons. In fact, CRTC overexpression enhances CLOCK/CYCLE (CLK/CYC)-activated transcription from tim but not per promoter in clock-less S2 cells whereas CRTC depletion suppresses it. Consistently, TIM overexpression partially but significantly rescues the behavioral rhythms in crtc mutants. Taken together, our data suggest that CRTC is a novel co-activator for the CLK/CYC-activated tim transcription to coordinate molecular rhythms with circadian behaviors over a 24-hour time-scale. We thus propose that CRTC-dependent clock mechanisms have co-evolved with selective clock genes among different species.ope

Modelling the Dynamics of Feral Alfalfa Populations and Its Management Implications

BACKGROUND: Feral populations of cultivated crops can pose challenges to novel trait confinement within agricultural landscapes. Simulation models can be helpful in investigating the underlying dynamics of feral populations and determining suitable management options. METHODOLOGY/PRINCIPAL FINDINGS: We developed a stage-structured matrix population model for roadside feral alfalfa populations occurring in southern Manitoba, Canada. The model accounted for the existence of density-dependence and recruitment subsidy in feral populations. We used the model to investigate the long-term dynamics of feral alfalfa populations, and to evaluate the effectiveness of simulated management strategies such as herbicide application and mowing in controlling feral alfalfa. Results suggest that alfalfa populations occurring in roadside habitats can be persistent and less likely to go extinct under current roadverge management scenarios. Management attempts focused on controlling adult plants alone can be counterproductive due to the presence of density-dependent effects. Targeted herbicide application, which can achieve complete control of seedlings, rosettes and established plants, will be an effective strategy, but the seedbank population may contribute to new recruits. In regions where roadside mowing is regularly practiced, devising a timely mowing strategy (early- to mid-August for southern Manitoba), one that can totally prevent seed production, will be a feasible option for managing feral alfalfa populations. CONCLUSIONS/SIGNIFICANCE: Feral alfalfa populations can be persistent in roadside habitats. Timely mowing or regular targeted herbicide application will be effective in managing feral alfalfa populations and limit feral-population-mediated gene flow in alfalfa. However, in the context of novel trait confinement, the extent to which feral alfalfa populations need to be managed will be dictated by the tolerance levels established by specific production systems for specific traits. The modelling framework outlined in this paper could be applied to other perennial herbaceous plants with similar life-history characteristics

Interleukin-2 gene transfer into human transitional cell carcinoma of the urinary bladder

Transitional cell carcinoma of the bladder is one of the human cancers most responsive to immunotherapy, and local interleukin-2 (IL-2) production appears to be an important requirement for immunotherapy to be effective. In this study, we engineered two human bladder cancer cell lines (RT112 and EJ) to constitutively release human IL-2 by retroviral vector-mediated gene transfer. Following infection and selection, stable and consistent production of biologically active IL-2 was demonstrated at both the mRNA and the protein level. Morphology, in vitro growth rate and proliferation, as well as other cytokine gene mRNA or membrane adhesion receptor expression, were not altered in IL-2 transduced cells as compared to their parental or control vector-infected counterparts. Moreover, IL-2 engineered cells lost their tumorigenicity into nu/nu mice and the mechanism of rejection appeared to involve multiple host effector cell populations, among which a prominent role was played by neutrophils and radiosensitive cells. These findings may offer support to the development of an IL-2-based gene therapy approach to human bladder cancer. 1999 Cancer Research Campaig

A General Framework for Formal Tests of Interaction after Exhaustive Search Methods with Applications to MDR and MDR-PDT

The initial presentation of multifactor dimensionality reduction (MDR) featured cross-validation to mitigate over-fitting, computationally efficient searches of the epistatic model space, and variable construction with constructive induction to alleviate the curse of dimensionality. However, the method was unable to differentiate association signals arising from true interactions from those due to independent main effects at individual loci. This issue leads to problems in inference and interpretability for the results from MDR and the family-based compliment the MDR-pedigree disequilibrium test (PDT). A suggestion from previous work was to fit regression models post hoc to specifically evaluate the null hypothesis of no interaction for MDR or MDR-PDT models. We demonstrate with simulation that fitting a regression model on the same data as that analyzed by MDR or MDR-PDT is not a valid test of interaction. This is likely to be true for any other procedure that searches for models, and then performs an uncorrected test for interaction. We also show with simulation that when strong main effects are present and the null hypothesis of no interaction is true, that MDR and MDR-PDT reject at far greater than the nominal rate. We also provide a valid regression-based permutation test procedure that specifically tests the null hypothesis of no interaction, and does not reject the null when only main effects are present. The regression-based permutation test implemented here conducts a valid test of interaction after a search for multilocus models, and can be applied to any method that conducts a search to find a multilocus model representing an interaction