Conducting Online Surveys Ball, Helen L.
Journal of human lactation,
08/2019, Letnik:
35, Številka:
3
Journal Article
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There is an established methodology for conducting survey research that aims to ensure rigorous research and robust outputs. With the advent of easy-to-use online survey platforms, however, the ...quality of survey studies has declined. This article summarizes the pros and cons of online surveys and emphasizes the key principles of survey research, for example questionnaire validation and sample selection. Numerous texts are available to guide researchers in conducting robust survey research online, however this is neither a quick nor easy undertaking. While online survey websites and software are useful for assisting in questionnaire design and delivery, they can also introduce sources of bias. Researchers considering conducting online surveys are encouraged to read carefully about how the principles of survey research can be applied to online formats in order to reduce bias and enhance rigor. In addition to alerting researchers to the pitfalls of online surveys this article also aims to equip readers of this journal with the knowledge of how to critically appraise publications based on online surveys.
Although mRNA and siRNA have significant therapeutic potential, their simultaneous delivery has not been previously explored. To facilitate the treatment of diseases associated with aberrant gene ...upregulation and downregulation, we sought to co-formulate siRNA and mRNA in a single lipidoid nanoparticle (LNP) formulation. We accommodated the distinct molecular characteristics of mRNA and siRNA in a formulation consisting of an ionizable and biodegradable amine-containing lipidoid, cholesterol, DSPC, DOPE, and PEG-lipid. Surprisingly, the co-formulation of siRNA and mRNA in the same LNP enhanced the efficacy of both drugs in vitro and in vivo. Compared to LNPs encapsulating siRNA only, co-formulated LNPs improved Factor VII gene silencing in mice from 44 to 87% at an siRNA dose of 0.03 mg/kg. Co-formulation also improved mRNA delivery, as a 0.5 mg/kg dose of mRNA co-formulated with siRNA induced three times the luciferase protein expression compared to when siRNA was not included. As not all gene therapy applications require both RNA drugs, we sought to extend the benefit of co-formulated LNPs to formulations encapsulating only a single type of RNA. We accomplished this by substituting the “helper” RNA with a negatively charged polymer, polystyrenesulfonate (PSS). LNPs containing PSS mediated the same level of protein silencing or expression as standard LNPs using 2–3-fold less RNA. For example, LNPs formulated with and without PSS induced 50% Factor VII silencing at siRNA doses of 0.01 and 0.03 mg/kg, respectively. Together, these studies demonstrate potent co-delivery of siRNA and mRNA and show that inclusion of a negatively charged “helper polymer” enhances the efficacy of LNP delivery systems.
The potential of mRNA therapeutics will be realized only once safe and effective delivery systems are established. Unfortunately, delivery vehicle development is stymied by an inadequate ...understanding of how the molecular properties of a vehicle confer efficacy. Here, a small library of lipidoid materials is used to elucidate structure–function relationships and identify a previously unappreciated parameter—lipid nanoparticle surface ionization—that correlates with mRNA delivery efficacy. The two most potent materials of the library, 306O10 and 306Oi10, induce substantial luciferase expression in mice following a single 0.75 mg kg−1 mRNA dose. These lipidoids, which have ten‐carbon tails and identical molecular weights, vary only in that the 306O10 tail is straight and the 306Oi10 tail has a one‐carbon branch. Remarkably, this small difference in structure conferred a tenfold improvement in 306Oi10 efficacy. The enhanced potency of this branched‐tail lipidoid is attributed to its strong surface ionization at the late endosomal pH of 5.0. A secondary lipidoid library confirms that Oi10 materials ionize more strongly and deliver mRNA more potently than lipidoids containing linear tails. Together, these data highlight the exquisite control that lipid chemistry exerts on the mRNA delivery process and show that branched‐tail lipids facilitate protein expression in animals.
Lipid nanoparticles (LNPs) are an exciting tool to deliver messenger RNA (mRNA) drugs that have the potential to treat any disease caused by faulty protein expression. This work describes the exquisite control that branched lipid tails exert on the mRNA delivery process by modulating LNP surface ionization at endosomal pH.
Oral delivery, a patient-friendly means of drug delivery, is preferred for local administration of intestinal therapeutics. Lipidoid nanoparticles, which have been previously shown to deliver siRNA ...to intestinal epithelial cells, have potential to treat intestinal disease. It is unknown, however, whether the oral delivery of these particles is possible. To better understand the fate of lipid nanoparticles in the gastrointestinal (GI) tract, we studied delivery under deconstructed stomach and intestinal conditions in vitro. Lipid nanoparticles remained potent and stable following exposure to solutions with pH values as low as 1.2. Efficacy decreased following exposure to "fed", but not "fasting" concentrations of pepsin and bile salts. The presence of mucin on Caco-2 cells also reduced potency, although this effect was mitigated slightly by increasing the percentage of PEG in the lipid nanoparticle. Mouse biodistribution studies indicated that siRNA-loaded nanoparticles were retained in the GI tract for at least 8 hours. Although gene silencing was not initially observed following oral LNP delivery, confocal microscopy confirmed that nanoparticles entered the epithelial cells of the mouse small intestine and colon. Together, these data suggest that orally-delivered LNPs should be protected in the stomach and upper intestine to promote siRNA delivery to intestinal epithelial cells.
Biotherapeutics are a promising class of molecules in drug discovery, but they are often limited to extracellular targets due to their poor cell penetration. High-throughput cell penetration assays ...are required for the optimization of biotherapeutics for enhanced cell penetration. We developed a HaloTag-based assay called the chloroalkane penetration assay (CAPA), which is quantitative, high-throughput, and compartment-specific. We demonstrate the ability of CAPA to profile extent of cytosolic penetration with respect to concentration, presence of serum, temperature, and time. We also used CAPA to investigate structure–penetration relationships for bioactive stapled peptides and peptides fused to cell-penetrating sequences. CAPA is not only limited to measuring cytosolic penetration. Using a cell line where HaloTag is localized to the nucleus, we show quantitative measurement of nuclear penetration. Going forward, CAPA will be a valuable method for measuring and optimizing the cell penetration of biotherapeutics.
Biological identifications through DNA barcodes Hebert, Paul D. N.; Cywinska, Alina; Ball, Shelley L. ...
Proceedings - Royal Society. Biological sciences/Proceedings - Royal Society. Biological Sciences,
02/2003, Letnik:
270, Številka:
1512
Journal Article
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Although much biological research depends upon species diagnoses, taxonomic expertise is collapsing. We are convinced that the sole prospect for a sustainable identification capability lies in the ...construction of systems that employ DNA sequences as taxon 'barcodes'. We establish that the mitochondrial gene cytochrome c oxidase I (COI) can serve as the core of a global bioidentification system for animals. First, we demonstrate that COI profiles, derived from the low-density sampling of higher taxonomic categories, ordinarily assign newly analysed taxa to the appropriate phylum or order. Second, we demonstrate that species-level assignments can be obtained by creating comprehensive COI profiles. A model COI profile, based upon the analysis of a single individual from each of 200 closely allied species of lepidopterans, was 100% successful in correctly identifying subsequent specimens. When fully developed, a COI identification system will provide a reliable, cost-effective and accessible solution to the current problem of species identification. Its assembly will also generate important new insights into the diversification of life and the rules of molecular evolution.
Purpose To evaluate the performance of a deep learning convolutional neural network (CNN) model compared with a traditional natural language processing (NLP) model in extracting pulmonary embolism ...(PE) findings from thoracic computed tomography (CT) reports from two institutions. Materials and Methods Contrast material-enhanced CT examinations of the chest performed between January 1, 1998, and January 1, 2016, were selected. Annotations by two human radiologists were made for three categories: the presence, chronicity, and location of PE. Classification of performance of a CNN model with an unsupervised learning algorithm for obtaining vector representations of words was compared with the open-source application PeFinder. Sensitivity, specificity, accuracy, and F1 scores for both the CNN model and PeFinder in the internal and external validation sets were determined. Results The CNN model demonstrated an accuracy of 99% and an area under the curve value of 0.97. For internal validation report data, the CNN model had a statistically significant larger F1 score (0.938) than did PeFinder (0.867) when classifying findings as either PE positive or PE negative, but no significant difference in sensitivity, specificity, or accuracy was found. For external validation report data, no statistical difference between the performance of the CNN model and PeFinder was found. Conclusion A deep learning CNN model can classify radiology free-text reports with accuracy equivalent to or beyond that of an existing traditional NLP model.
RSNA, 2017 Online supplemental material is available for this article.
Recent discoveries have implicated the gut microbiome in the progression and severity of Parkinson’s disease; however, how gut bacteria affect such neurodegenerative disorders remains unclear. Here, ...we report that the Bacillus subtilis probiotic strain PXN21 inhibits α-synuclein aggregation and clears preformed aggregates in an established Caenorhabditis elegans model of synucleinopathy. This protection is seen in young and aging animals and is partly mediated by DAF-16. Multiple B. subtilis strains trigger the protective effect via both spores and vegetative cells, partly due to a biofilm formation in the gut of the worms and the release of bacterial metabolites. We identify several host metabolic pathways differentially regulated in response to probiotic exposure, including sphingolipid metabolism. We further demonstrate functional roles of the sphingolipid metabolism genes lagr-1, asm-3, and sptl-3 in the anti-aggregation effect. Our findings provide a basis for exploring the disease-modifying potential of B. subtilis as a dietary supplement.
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•B. subtilis PXN21 inhibits and reverses α-syn aggregation in a C. elegans model•Spores and vegetative cells protect through different mechanisms•The probiotic inhibits α-syn aggregation by changing the host sphingolipid metabolism•Biofilm formation in the gut and bacterial metabolites reduce α-syn aggregation
How the gut microbiome affects Parkinson’s disease remains unclear. Goya et al. show that the probiotic B. subtilis strain PXN21 inhibits and clears α-synuclein aggregation in a C. elegans model. The bacterium acts via metabolites and biofilm formation to activate protective pathways in the host, including DAF-16/FOXO and sphingolipid metabolism.
Early reduction and fixation will improve a patient’s outcome and quality of life through better return of function.23 Patients are routinely discharged with analgesia the day after surgery following ...a postoperative radiograph to assess fracture reduction. Learning points Substance misuse, including alcohol, has been linked to up to 69% of mandible fractures.4 Patient outcome This patient was discharged the day after surgery and was reviewed in the outpatient clinic at 2 and 4 weeks postoperatively. Provenance and peer review: not commissioned; externally peer reviewed. 1 Rashid A Eyeson J Haider D van Gijn D Fan K. Incidence and patterns of mandibular fractures during a 5-year period in a London teaching hospital.
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