190 research outputs found

    External quality assessment in resource–limited countries

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    Introduction: Health laboratory services are a critical component of national health systems but face major operational challenges in resource-limited (RL) settings. New funding for health systems strengthening in RL countries has increased the demand for diagnostics and provided opportunities to address these constraints. An approach to sustainably strengthen national laboratory systems in sub-Saharan African countries is the Strengthening Laboratory Management Toward Accreditation (SLMTA) programme. External Quality Assessment (EQA) is a requirement for laboratory accreditation. EQA comprises proficiency testing (PT), rechecking of samples and on-site evaluation. Materials and methods: A systematic literature search was conducted to identify studies addressing laboratory EQA and quality monitoring in RL countries. Unpublished reports were also sought from national laboratory authorities and personnel. Results: PT schemes in RL countries are provided by commercial companies, institutions in developed countries and national programmes. Most government-supported PT schemes address single diseases using a vertical approach. Regional approaches to delivering PT have also been implemented across RL countries. Rechecking schemes address mainly tuberculosis (TB), malaria and human immunodeficiency virus (HIV); integrated rechecking programmes have been piloted. Constraints include sample transportation, communication of results, unknown proficiency of referee staff and limited resources for corrective action. Global competency assessment standards for malaria microscopists have been established. Conclusions: EQA is vital for monitoring laboratory performance and maintaining quality of laboratory services, and is a valuable tool for identifying and assessing technology in use, identifying gaps in laboratory performance and targeting training needs. Accreditation of PT providers and competency of EQA personnel must be ensured

    Interaction Between Climatic, Environmental, and Demographic Factors on Cholera Outbreaks in Kenya

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    Background: Cholera remains an important public health concern in developing countries including Kenya where 11,769 cases and 274 deaths were reported in 2009 according to the World Health Organization (WHO). This ecological study investigates the impact of various climatic, environmental, and demographic variables on the spatial distribution of cholera cases in Kenya. Methods: District-level data was gathered from Kenya’s Division of Disease Surveillance and Response, the Meteorological Department, and the National Bureau of Statistics. The data included the entire population of Kenya from 1999 to 2009. Results: Multivariate analyses showed that districts had an increased risk of cholera outbreaks when a greater proportion of the population lived more than five kilometers from a health facility (RR: 1.025 per 1% increase; 95% CI: 1.010, 1.039), bordered a body of water (RR: 5.5; 95% CI: 2.472, 12.404), experienced increased rainfall from October to December (RR: 1.003 per 1 mm increase; 95% CI: 1.001, 1.005), and experienced decreased rainfall from April to June (RR: 0.996 per 1 mm increase; 95% CI: 0.992, 0.999). There was no detectable association between cholera and population density, poverty, availability of piped water, waste disposal methods, rainfall from January to March, or rainfall from July to September. Conclusion: Bordering a large body of water, lack of health facilities nearby, and changes in rainfall were significantly associated with an increased risk of cholera in Kenya

    Meeting report: discussions and preliminary findings on extracellular RNA measurement methods from laboratories in the NIH Extracellular RNA Communication Consortium

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    Extracellular RNAs (exRNAs) have been identified in all tested biofluids and have been associated with a variety of extracellular vesicles, ribonucleoprotein complexes and lipoprotein complexes. Much of the interest in exRNAs lies in the fact that they may serve as signalling molecules between cells, their potential to serve as biomarkers for prediction and diagnosis of disease and the possibility that exRNAs or the extracellular particles that carry them might be used for therapeutic purposes. Among the most significant bottlenecks to progress in this field is the lack of robust and standardized methods for collection and processing of biofluids, separation of different types of exRNA-containing particles and isolation and analysis of exRNAs. The Sample and Assay Standards Working Group of the Extracellular RNA Communication Consortium is a group of laboratories funded by the U.S. National Institutes of Health to develop such methods. In our first joint endeavour, we held a series of conference calls and in-person meetings to survey the methods used among our members, placed them in the context of the current literature and used our findings to identify areas in which the identification of robust methodologies would promote rapid advancements in the exRNA field

    Towards harmonization of microscopy methods for malaria clinical research studies

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    Microscopy performed on stained films of peripheral blood for detection, identification and quantification of malaria parasites is an essential reference standard for clinical trials of drugs, vaccines and diagnostic tests for malaria. The value of data from such research is greatly enhanced if this reference standard is consistent across time and geography. Adherence to common standards and practices is a prerequisite to achieve this. The rationale for proposed research standards and procedures for the preparation, staining and microscopic examination of blood films for malaria parasites is presented here with the aim of improving the consistency and reliability of malaria microscopy performed in such studies. These standards constitute the core of a quality management system for clinical research studies employing microscopy as a reference standard. They can be used as the basis for the design of training and proficiency testing programmes as well as for procedures and quality assurance of malaria microscopy in clinical research.Publisher PDFPeer reviewe

    Performance of a fully‐automated system on a WHO malaria microscopy evaluation slide set

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    Background: Manual microscopy remains a widely-used tool for malaria diagnosis and clinical studies, but it has inconsistent quality in the field due to variability in training and field practices. Automated diagnostic systems based on machine learning hold promise to improve quality and reproducibility of field microscopy. The World Health Organization (WHO) has designed a 55-slide set (WHO 55) for their External Competence Assessment of Malaria Microscopists (ECAMM) programme, which can also serve as a valuable benchmark for automated systems. The performance of a fully-automated malaria diagnostic system, EasyScan GO, on a WHO 55 slide set was evaluated. Methods: The WHO 55 slide set is designed to evaluate microscopist competence in three areas of malaria diagnosis using Giemsa-stained blood films, focused on crucial field needs: malaria parasite detection, malaria parasite species identification (ID), and malaria parasite quantitation. The EasyScan GO is a fully-automated system that combines scanning of Giemsa-stained blood films with assessment algorithms to deliver malaria diagnoses. This system was tested on a WHO 55 slide set. Results: The EasyScan GO achieved 94.3 % detection accuracy, 82.9 % species ID accuracy, and 50 % quantitation accuracy, corresponding to WHO microscopy competence Levels 1, 2, and 1, respectively. This is, to our knowledge, the best performance of a fully-automated system on a WHO 55 set. Conclusions: EasyScan GO’s expert ratings in detection and quantitation on the WHO 55 slide set point towards its potential value in drug efficacy use-cases, as well as in some case management situations with less stringent species ID needs. Improved runtime may enable use in general case management settings

    The Crystal Structure and RNA-Binding of an Orthomyxovirus Nucleoprotein

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    Genome packaging for viruses with segmented genomes is often a complex problem. This is particularly true for influenza viruses and other orthomyxoviruses, whose genome consists of multiple negative-sense RNAs encapsidated as ribonucleoprotein (RNP) complexes. To better understand the structural features of orthomyxovirus RNPs that allow them to be packaged, we determined the crystal structure of the nucleoprotein (NP) of a fish orthomyxovirus, the infectious salmon anemia virus (ISAV) (genus Isavirus). As the major protein component of the RNPs, ISAV-NP possesses a bi-lobular structure similar to the influenza virus NP. Because both RNA-free and RNA-bound ISAV NP forms stable dimers in solution, we were able to measure the NP RNA binding affinity as well as the stoichiometry using recombinant proteins and synthetic oligos. Our RNA binding analysis revealed that each ISAV-NP binds ,12 nts of RNA, shorter than the 24ヨ28 nts originally estimated for the influenza A virus NP based on population average. The 12-nt stoichiometry was further confirmed by results from electron microscopy and dynamic light scattering. Considering that RNPs of ISAV and the influenza viruses have similar morphologies and dimensions, our findings suggest that NP-free RNA may exist on orthomyxovirus RNPs, and selective RNP packaging may be accomplished through direct RNA-RNA interactions

    HCV co-infection in HIV positive population in British Columbia, Canada

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    <p>Abstract</p> <p>Background</p> <p>As HIV and hepatitis C (HCV) share some modes of transmission co-infection is not uncommon. This study used a population-based sample of HIV and HCV tested individuals to determine the prevalence of HIV/HCV co-infection, the sequence of virus diagnoses, and demographic and associated risk factors.</p> <p>Methods</p> <p>Positive cases of HIV were linked to the combined laboratory database (of negative and positive HCV antibody results) and HCV reported cases in British Columbia (BC).</p> <p>Results</p> <p>Of 4,598 HIV cases with personal identifiers, 3,219 (70%) were linked to the combined HCV database, 1,700 (53%) of these were anti-HCV positive. HCV was diagnosed first in 52% of co-infected cases (median time to HIV identification 3 1/2 years). HIV and HCV was diagnosed within a two week window in 26% of cases. Among individuals who were diagnosed with HIV infection at baseline, subsequent diagnoses of HCV infection was independently associated with: i) intravenous drug use (IDU) in males and females, Hazard Ratio (HR) = 6.64 (95% CI: 4.86-9.07) and 9.76 (95% CI: 5.76-16.54) respectively; ii) reported Aboriginal ethnicity in females HR = 2.09 (95% CI: 1.34-3.27) and iii) males not identified as men-who-have-sex-with-men (MSM), HR = 2.99 (95% CI: 2.09-4.27).</p> <p>Identification of HCV first compared to HIV first was independently associated with IDU in males and females OR = 2.83 (95% CI: 1.84-4.37) and 2.25 (95% CI: 1.15-4.39) respectively, but not Aboriginal ethnicity or MSM. HIV was identified first in 22%, with median time to HCV identification of 15 months;</p> <p>Conclusion</p> <p>The ability to link BC public health and laboratory HIV and HCV information provided a unique opportunity to explore demographic and risk factors associated with HIV/HCV co-infection. Over half of persons with HIV infection who were tested for HCV were anti-HCV positive; half of these had HCV diagnosed first with HIV identification a median 3.5 years later. This highlights the importance of public health follow-up and harm reduction measures for people identified with HCV to prevent subsequent HIV infection.</p

    Process evaluation of a peer-led antenatal breastfeeding class for fathers: perceptions of facilitators and participants

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    Background: The Parent Infant Feeding Initiative (PIFI) was a factorial, randomised controlled trial that aimed to prolong exclusive breastfeeding by targeting expecting fathers. One of the intervention strategies evaluated was a father-focused breastfeeding class facilitated by a male peer facilitator. The aim of this mixed-methods descriptive study was to 1) evaluate the feedback provided from participants of the class and 2) explore the motivations and experiences of volunteer male peer facilitators trained to deliver the class. Methods: Father-focused breastfeeding antenatal (FFAB) classes were conducted in six Western Australian hospitals between August 2015 and December 2016. Following each peer facilitated FFAB class, expecting father participants completed an evaluation form to assess their satisfaction with the format, facilitation and content, in addition to whether their expectations and confidence to manage breastfeeding problems had changed. Feedback to open-ended questions was analysed using content analysis to identify learnings and suggestions for improvements. At the completion of PIFI, individual telephone interviews were undertaken with 14 peer facilitators to gain insight into their motivations for volunteering and experiences of conducting the classes. Transcripts from interviews were analysed using Braun and Clarke’s six phases for thematic analysis. Results: Participant evaluation forms were completed by 678 of the 697 father participants (98%). Overall satisfaction with class format, facilitation and content was high with 90% or more of fathers either strongly agreeing or agreeing with each positively-phrased evaluation item. Class participants enjoyed interacting with other fathers, appreciated validation of their role, were not always aware of the importance of breastfeeding or potential difficulties, valued the anticipatory guidance around what to expect in the early weeks of parenting and appreciated learning practical breastfeeding support strategies. Peer facilitators indicated they felt well prepared and supported to conduct FFAB classes. Analysis of interview transcripts revealed common experiences of the peer facilitators incorporating four themes: ‘Highlights of being a facilitator’, ‘Challenges’, ‘Mourning the project completion’ and ‘Satisfaction with training and support’. Conclusion: Father-focused breastfeeding classes supported by volunteer male peer facilitators are a feasible and acceptable way of engaging fathers as breastfeeding supporters. Trial registration: ACTRN12614000605695. Registered 6 June 2014

    Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas

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    This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin

    VCAM-1 and VLA-4 Modulate Dendritic Cell IL-12p40 Production in Experimental Visceral Leishmaniasis

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    Vascular cell adhesion molecule-1 (VCAM-1) interacts with its major ligand very late antigen-4 (VLA-4) to mediate cell adhesion and transendothelial migration of leukocytes. We report an important role for VCAM-1/VLA-4 interactions in the generation of immune responses during experimental visceral leishmaniasis caused by Leishmania donovani. Our studies demonstrate that these molecules play no direct role in the recruitment of leukocytes to the infected liver, but instead contribute to IL-12p40-production by splenic CD8+ dendritic cells (DC). Blockade of VCAM-1/VLA-4 interactions using whole antibody or anti-VCAM-1 Fab′ fragments reduced IL-12p40 mRNA accumulation by splenic DC 5 hours after L. donovani infection. This was associated with reduced anti-parasitic CD4+ T cell activation in the spleen and lowered hepatic IFNγ, TNF and nitric oxide production by 14 days post infection. Importantly, these effects were associated with enhanced parasite growth in the liver in studies with either anti-VCAM-1 or anti-VLA-4 antibodies. These data indicate a role for VCAM-1 and VLA-4 in DC activation during infectious disease
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