113 research outputs found
A proposed framework for the development and qualitative evaluation of West Nile virus models and their application to local public health decision-making
West Nile virus(WNV) is a globally distributed mosquito-borne virus of great public health concern. The number of WNV human cases and mosquito infection patterns vary in space and time. Many statistical models have been developed to understand and predict WNV geographic and temporal dynamics. However, these modeling efforts have been disjointed with little model comparison and inconsistent validation. In this paper, we describe a framework to unify and standardize WNV modeling efforts nationwide. WNV risk, detection, or warning models for this review were solicited from active research groups working in different regions of the United States. A total of 13 models were selected and described. The spatial and temporal scales of each model were compared to guide the timing and the locations for mosquito and virus surveillance, to support mosquito vector control decisions, and to assist in conducting public health outreach campaigns at multiple scales of decision-making. Our overarching goal is to bridge the existing gap between model development, which is usually conducted as an academic exercise, and practical model applications, which occur at state, tribal, local, or territorial public health and mosquito control agency levels. The proposed model assessment and comparison framework helps clarify the value of individual models for decision-making and identifies the appropriate temporal and spatial scope of each model. This qualitative evaluation clearly identifies gaps in linking models to applied decisions and sets the stage for a quantitative comparison of models. Specifically, whereas many coarse-grained models (county resolution or greater) have been developed, the greatest need is for fine-grained, short-term planning models (m–km, days–weeks) that remain scarce. We further recommend quantifying the value of information for each decision to identify decisions that would benefit most from model input
Endoscopic sphincterotomy to prevent post-ERCP pancreatitis after self-expandable metal stent placement for distal malignant biliary obstruction (SPHINX): a multicentre, randomised controlled trial
Background: Endoscopic retrograde cholangiopancreatography (ERCP) with fully covered self-expandable metal stent (FCSEMS) placement is the preferred approach for biliary drainage in patients with suspected distal malignant biliary obstruction (MBO). However, FCSEMS placement is associated with a high risk of post-ERCP pancreatitis (PEP). Endoscopic sphincterotomy prior to FCSEMS placement may reduce PEP risk. Objective: To compare endoscopic sphincterotomy to no sphincterotomy prior to FCSEMS placement. Design: This multicentre, randomised, superiority trial was conducted in 17 hospitals and included patients with suspected distal MBO. Patients were randomised during ERCP to receive either endoscopic sphincterotomy (sphincterotomy group) or no sphincterotomy (control group) prior to FCSEMS placement. The primary outcome was PEP within 30 days. Secondary outcomes included procedure-related complications and 30-day mortality. An interim analysis was performed after 50% of patients (n=259) had completed follow-up. Results: Between May 2016 and June 2023, 297 patients were included in the intention-to-treat analysis, with 156 in the sphincterotomy group and 141 in the control group. After the interim analysis, the study was terminated prematurely due to futility. PEP did not differ between groups, occurring in 26 patients (17%) in the sphincterotomy group compared with 30 patients (21%) in the control group (relative risk 0.78, 95% CI 0.49 to 1.26, p=0.37). There were no significant differences in bleeding, perforation, cholangitis, cholecystitis or 30-day mortality. Conclusion: This trial found that endoscopic sphincterotomy was not superior to no sphincterotomy in reducing PEP in patients with distal MBO. Therefore, there was insufficient evidence to recommend routine endoscopic sphincterotomy prior to FCEMS placement. Trial registration number: NL5130
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2D versus 3D human induced pluripotent stem cell-derived cultures for neurodegenerative disease modelling
Neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD) and amyotrophic lateral sclerosis (ALS), affect millions of people every year and so far, there are no therapeutic cures available. Even though animal and histological models have been of great aid in understanding disease mechanisms and identifying possible therapeutic strategies, in order to find disease-modifying solutions there is still a critical need for systems that can provide more predictive and physiologically relevant results. One possible avenue is the development of patient-derived models, e.g. by reprogramming patient somatic cells into human induced pluripotent stem cells (hiPSCs), which can then be differentiated into any cell type for modelling. These systems contain key genetic information from the donors, and therefore have enormous potential as tools in the investigation of pathological mechanisms underlying disease phenotype, and progression, as well as in drug testing platforms. hiPSCs have been widely cultured in 2D systems, but in order to mimic human brain complexity, 3D models have been proposed as a more advanced alternative. This review will focus on the use of patient-derived hiPSCs to model AD, PD, HD and ALS. In brief, we will cover the available stem cells, types of 2D and 3D culture systems, existing models for neurodegenerative diseases, obstacles to model these diseases in vitro, and current perspectives in the field
Interactions of nisin and pediocin PA-1 with closely related lactic acid bacteria that manifest over 100-fold differences in bacteriocin sensitivity.
The natural variation in the susceptibilities of gram-positive bacteria towards the bacteriocins nisin and pediocin PA-1 is considerable. This study addresses the factors associated with this variability for closely related lactic acid bacteria. We compared two sets of nonbacteriocinogenic strains for which the MICs of nisin and pediocin PA-1 differed 100- to 1,000-fold: Lactobacillus sake DSM20017 and L. sake DSM20497 and Pediococcus dextrinicus and Pediococcus pentosaccus. Strikingly, the bacteriocin-sensitive and -insensitive strains showed a similar concentration-dependent dissipation of their membrane potential (delta psi) after exposure to these bacteriocins. The bacteriocin-induced dissipation of delta psi below the MICs for the insensitive strains did not coincide with a reduction of intracellular ATP pools and glycolytic rates. This was not observed with the sensitive strains. Analysis of membrane lipid properties revealed minor differences in the phospho- and glycolipid compositions of both sets of strains. The interactions of the bacteriocins with strain-specific lipids were not significantly different in a lipid monolayer assay. Further lipid analysis revealed higher in situ membrane fluidity of the bacteriocin-sensitive Pediococcus strain compared with that for the insensitive strain, but the opposite was found for the L. sake strains. Our results provide evidence that the association of bacteriocins with the cell membrane and their subsequent insertion take place in a similar way for cells that have a high or a low natural tolerance towards bacteriocins. For insensitive strains, overall membrane constitution rather than mere membrane fluidity may preclude the formation of pores with sufficient diameters and lifetimes to ultimately cause cell death
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