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Clostridium perfringens produces an adhesive pilus required for the pathogenesis of necrotic enteritis in poultry
No full textClostridium perfringens type G strains cause necrotic enteritis (NE) in poultry, an economically important disease that is a major target of in-feed antibiotics. NE is a multifactorial disease, involving not only the critically important NetB toxin but also additional virulence and virulence-associated factors. We previously identified a C. perfringens chromosomal locus (VR-10B) associated with disease-causing strains that is predicted to encode a sortase-dependent pilus. In the current study, we sought to provide direct evidence for the production of a pilus by C. perfringens and establish its role in NE pathogenesis. Pilus structures in virulent C. perfringens strain CP1 were visualized by transmission electron microscopy (TEM) of immunogold-labeled cells. Filamentous structures were observed extending from the cell surface in wild-type CP1 but not from isogenic pilin-null mutant strains. In addition, immunoblotting of cell surface proteins demonstrated that CP1, but not the null mutant strains, produced a high molecular weight ladder-like pattern characteristic of a pilus polymer. Binding to collagen types I, II, and IV was significantly reduced (Tukey’s test, P < 0.01) in all three pilin mutants compared to CP1 and could be specifically blocked by CnaA and FimA antisera, indicating that these pilins participate in adherence. Furthermore, fimA and fimB null mutants were both severely attenuated in their ability to cause disease in an in vivo chicken NE challenge model. Together, these results provide the first direct evidence for the production of a sortase-dependent pilus by C. perfringens and confirm its critical role in NE pathogenesis and collagen binding.
IMPORTANCE In necrotic enteritis (NE), an intestinal disease of chickens, Clostridium perfringens cells adhere tightly to damaged intestinal tissue, but the factors involved are not known. We previously discovered a cluster of C. perfringens genes predicted to encode a pilus, a hair-like bacterial surface structure commonly involved in adherence. In the current study, we have directly imaged this pilus using transmission electron microscopy (TEM). We also show that inactivation of the pilus genes stops pilus production, significantly reducing the bacterium's ability to bind collagen and cause disease. Importantly, this is the first direct evidence for the production of a sortase-dependent pilus by C. perfringens, revealing a promising new target for developing therapeutics to combat this economically important disease.Agriculture and Agri-Food Canada and Canadian Poultry Research Counci
Comparing blanket vs. selective dry cow treatment approaches for elimination and prevention of intramammary infections during the dry period: A systematic review and meta-analysis
No full textA systematic review and a series of meta-analyses were conducted to investigate the efficacy of selective dry cow antimicrobial treatment (SDCT) (in which only infected quarters/cows were treated with an antimicrobial) compared with blanket dry cow treatment (BDCT) (all quarters/all cows received an antimicrobial, regardless of their infection status). A full detailed protocol was published before initiating this review. Studies reporting on the (1) proportion of untreated quarters or cows when using SDCT, (2) intramammary infection (IMI) incidence risk over the dry period, (3) IMI elimination risk, (4) post-calving IMI prevalence, (5) early lactation clinical mastitis incidence, or (6) subsequent lactation milk yield and somatic cell counts were considered eligible. Thirteen articles representing 12 controlled trials, whether randomized or not, were available for analyses. SDCT reduced the use of antimicrobials at dry off by 66% (95% CI: 49–80). There was no difference in the elimination of existing IMI at dry off, between SDCT and BDCT. Meta-regression showed that the risk of IMI incidence during the dry period, IMI risk at calving, early lactation clinical mastitis risk, and early lactation milk yield and somatic cell counts did not differ between SDCT and BDCT as long as an internal teat sealant (65% bismuth subnitrate) was administered to untreated healthy quarters/cows at dry off. For trials not using internal teat sealants, SDCT resulted in higher risk than BDCT of acquiring a new IMI during the dry period and of harboring an IMI at calving. Lines of evidence strongly support that SDCT would reduce the use of antimicrobials at dry off, without any detrimental effect on udder health or milk production during the 1st months of the subsequent lactation, if, and only if, internal teat sealants are used for healthy, untreated quarters/cows.Agriculture and Agri-Food CanadaDairy Farmers of CanadaCanadian Dairy NetworkCanadian Dairy CommissionFonds de recherche du Québec—Nature et technologie
A systematic review of augmented reality tourism research: What is now and what is next?
No full textThe application of augmented reality in tourism is flourishing and promising, bringing an emerging body of studies. While virtual reality might be a virtual threat to the travel and tourism as being a potential substitute, augmented reality allows users to interact with the real environment that could potentially enhance visitors’ experience. Distinguishing from reviews that combine studies of augmented reality and virtual reality, this study systematically investigates the current state of augmented reality research exclusively in the tourism literature. The results identify five established and emerging research clusters, with one predominant cluster that focuses on user acceptance of augmented reality, commonly applying the technology acceptance model. A meta-analysis of a subset of four empirical studies reveals that perceived ease of use has an overall influence of 52.79% on perceived usefulness. Lastly, a concept map visually presents the constructs that have been explored across the clusters. Based on our review, future research directions are proposed to advance knowledge in the emerging area of gamification, to explore the potential negative consequences of augmented reality, and to apply more innovative methods and study designs
Parents’ experiences and information needs while caring for a child with functional constipation: A systematic review
No full textPediatric functional constipation (FC) reportedly affects at least 1 in 10 children worldwide. Parent and family education is a key component for successful treatment, yet there is little research exploring what information families need and how to best support them. The aim of this review is to synthesize current evidence on the experiences and information needs of parents caring for a child with FC. We systematically searched published research and completed screening against a priori inclusion criteria. Thirteen studies (n = 10 quantitative, n = 3 qualitative) were included. We found 2 main themes, precarious footing and profound and pervasive effects. Heavy caregiving burdens fueled doubts, misinformation, relationship breakdown, and treatment deviation. In light of clinical recommendations, our findings reveal a potential mismatch between parents’ needs and care provision for FC. It is likely that both parents and health care providers would benefit from resources and interventions to improve care related to pediatric FC.Networks of Centres of Excellence Knowledge MobilizationWomen and Children’s Health Research FoundationCIHR FoundationStollery Children’s Hospital Foundatio
Clinical care manager file review and study: Services in support of case managed clients at Veterans Affairs Canada
No full textStandardised ginseng extract G115® potentiates the antidepressant-like properties of fluoxetine in the forced swim test
No full textOBJECTIVE:
Ginsenosides, biologically-active components of the root of Panax ginseng, have been reported to have therapeutic benefits in a number of disease states including psychiatric conditions such as major depressive disorder. Our objective was to determine if a standardized commercial ginseng extract, G115®, could reduce the signs of behavioural despair commonly observed in animal models of depression either alone or in combination with the selective serotonin reuptake inhibitor fluoxetine.
METHODS:
Male Sprague-Dawley (SD) rats (N=51) were divided into four groups: vehicle control, G115® ginseng root extract, fluoxetine and fluoxetine plus G115®. Rats were trained to voluntarily consume treatments twice daily for 14 days and were then tested in an open field (OF), elevated plus maze (EPM) and forced swim test (FST). Post-mortem hippocampal and prefrontal cortex tissue was analysed for expression of brain derived neurotrophic factor (BDNF) and tropomyosin receptor kinase B (TrkB) by Western Blot.
RESULTS:
One-way ANOVA revealed no significant group differences in open field or plus maze performance on any variable examined. In the forced swim test fluoxetine significantly reduced immobility time and increased latency to immobility. The effects of fluoxetine were further significantly potentiated by co-administration of G115®. Post-mortem tissue analysis revealed significant group differences in BDNF expression in the left hippocampus and left prefrontal cortex without any accompanying changes in TrkB expression.
CONCLUSIONS:
We conclude that oral G115® significantly potentiates the antidepressant-like effect of fluoxetine in the forced swim test in the absence of potentially confounding effects on locomotion and anxiety
The moral and religious thought of Yi Hwang (Toegye): A study of Korean Neo-Confucian ethics and spirituality
No full textThis book presents Yi Hwang (1501–1570)—better known by his pen name, Toegye—Korea’s most eminent Confucian philosopher. It is a pioneering study of Toegye’s moral and religious thought that discusses his holistic ideas and experiences as a scholar, thinker, and spiritual practitioner. This study includes Toegye’s major biographies and letters as well as his famous Jaseongnok (Record of self-reflection) and Seonghak sipdo (Ten diagrams on sagely learning). Edward Chung explains key concepts, original quotations, annotated notes, and thought-provoking comments to bring this monumental thinker and his work to life. Chung also considers comparative and interreligious perspectives and their contemporary relevance. By offering groundbreaking insights into Neo-Confucianism, this book sheds fresh light on the breadth and depth of Toegye’s ethics and spirituality, and is an important source for scholars and students in Korean and Confucian studies and comparative philosophy and religion
Research‐ and health‐related youth advisory groups in Canada: An environmental scan with stakeholder interviews
No full textBackground
Engaging youth throughout the research process improves research quality and outcomes. Youth advisory groups provide one way for youth to express their opinions on relevant issues.
Objective
This study aimed to identify research- and health-related youth advisory groups (‘groups’) in Canada and understand the best practices of these groups.
Methods
Google searches and supplementary methods were used to identify relevant groups in Canada. Group information was extracted from websites or through interviews with key informants.
Results
We identified 40 groups. Groups were commonly part of a hospital/healthcare facility, nonprofit/health organization or research group. The majority focused on a specific content area, most commonly, mental health. Over half the groups advised on health services. Members' ages ranged from 9 to 35 years. The number of members ranged from 5 to 130. Interviews (n = 12) identified seven categories relating to group practices: (a) group purpose/objectives, (b) group development, (c) group operations, (d) group structure, (e) adult involvement, (f) membership and recruitment and (g) group access. Challenges and facilitators to the success of groups were described within the following themes: (a) retaining engagement, (b) creating a safe environment and (c) putting youth in positions of influence. Advice and recommendations were provided regarding the development of a new group.
Conclusion
This study provides a comprehensive overview of research- and health-related youth advisory groups in Canada. This information can be used to identify groups that stakeholders could access as well as inform the development of a new group.Stollery Children's Hospital Foundatio
Development, validation, and application of a selective saliva-based cortisol biosensor
No full textCortisol, a steroid hormone, is essential in various physiological processes and follows a circadian rhythm throughout a day-night cycle. Abnormal levels of cortisol can be attributed to diseases, but most notably, it is caused by stress. Therefore, cortisol is widely known as a stress biomarker. Having a device to analyze salivary cortisol is essential in identifying environmental or behavioural triggers that can lead to stress. Analysis through saliva-based cortisol sensing offers a method of obtaining samples in a non-invasive form, minimizing additional stress. The current standard methods of measurements have disadvantages of being time-consuming, expensive and require specialized equipment to run the analysis, such as enzyme-linked immunosorbent assay (ELISA). Therefore, there is a need for a device that is cost-effective, fast, portable, and easy to use, thus creating a point-of-care (POC) device for the measurement of salivary cortisol.
In this thesis, a lateral flow assay (LFA) technique have been implemented for rapid quantitative analyses of salivatory cortisol. Parametric studies performed to investigate the effects of LFA preparation and construction on the measurement of cortisol sample concentrations. The studies conducted determined the characteristics of the LFA, such as sensitivity and selectivity to establish limitations and reproducibility. Horse saliva was used to test the LFA performance and was compared to an ELISA measurement. MATLAB was used in the development of an automated image processing algorithm. This algorithm enabled automated and faster measurement of cortisol in saliva through extraction of novel transient features. It was concluded that using automated image processing and advanced feature extraction a higher level of selectivity can be achieved
Improved performance of a nanorefrigerant-based vapor compression refrigeration system: A new alternative
No full textAn attempt has been made to improve the heat transfer characteristics of the vapor compression refrigeration cycle using nanorefrigerant (R134a and Al2O3, size 20 nm). The performance parameters such as, coefficient of performance, cooling capacity, energy consumption, and temperature drop across condenser and evaporator have been investigated and analyzed. This has been done by varying the mass fraction of nanoparticles of Al2O3 (0.5–1 wt%) and the flow rate of nanorefrigerant. The investigation has been carried out using three types of nanorefrigerants, i.e. pure R134a, R134a+Al2O3 (0.5 wt%), and R134a+Al2O3 (1 wt%) at flow rates of 6.5 L/h and 11 L/h, respectively. The coefficient of performance of the refrigeration system using 0.5% of Al2O3 (wt%) is found to be improving with volume flow rates of nanorefrigerant, i.e. 7.20% for 6.5 L/h and 16.34% for 11 L/h. The use of nanorefrigerant (R134a+Al2O3) has also resulted in a significant increase in the cooling capacity of the refrigeration system. A substantial drop in the temperature across the condenser (3.0–23.77%), and gain in temperature across the evaporator (4.69–39.30%) is also observed for the refrigeration system under investigation