The number of patients diagnosed with chronic bile duct disease is increasing and in most cases these diseases result in chronic ductular scarring, necessitating liver transplantation. The formation ...of ductular scaring affects liver function; however, scar-generating portal fibroblasts also provide important instructive signals to promote the proliferation and differentiation of biliary epithelial cells. Therefore, understanding whether we can reduce scar formation while maintaining a pro-regenerative microenvironment will be essential in developing treatments for biliary disease. Here, we describe how regenerating biliary epithelial cells express Wnt-Planar Cell Polarity signalling components following bile duct injury and promote the formation of ductular scars by upregulating pro-fibrogenic cytokines and positively regulating collagen-deposition. Inhibiting the production of Wnt-ligands reduces the amount of scar formed around the bile duct, without reducing the development of the pro-regenerative microenvironment required for ductular regeneration, demonstrating that scarring and regeneration can be uncoupled in adult biliary disease and regeneration.
In addition to heme's role as the prosthetic group buried inside many different proteins that are ubiquitous in biology, there is new evidence that heme has substantive roles in cellular signaling ...and regulation. This means that heme must be available in locations distant from its place of synthesis (mitochondria) in response to transient cellular demands. A longstanding question has been to establish the mechanisms that control the supply and demand for cellular heme. By fusing a monomeric heme-binding peroxidase (ascorbate peroxidase, mAPX) to a monomeric form of green-fluorescent protein (mEGFP), we have developed a heme sensor (mAPXmEGFP) that can respond to heme availability. By means of fluorescence lifetime imaging, this heme sensor can be used to quantify heme concentrations; values of the mean fluorescence lifetime (τ
) for mAPX-mEGFP are shown to be responsive to changes in free (unbound) heme concentration in cells. The results demonstrate that concentrations are typically limited to one molecule or less within cellular compartments. These miniscule amounts of free heme are consistent with a system that sequesters the heme and is able to buffer changes in heme availability while retaining the capability to mobilize heme when and where it is needed. We propose that this exchangeable supply of heme can operate using mechanisms for heme transfer that are analogous to classical ligand-exchange mechanisms. This exquisite control, in which heme is made available for transfer one molecule at a time, protects the cell against the toxic effect of excess heme and offers a simple mechanism for heme-dependent regulation in single-molecule steps.
Accumulating evidence suggests a new role for cellular heme as a signalling molecule, in which interactions with target proteins are more transient than found with traditionally-defined hemoproteins. ...To study this role, a precise method is needed for determining the heme-binding affinity (or dissociation constant, Kd). Estimates of Kd are commonly made following a spectrophotometric titration of an apo-protein with hemin. An impediment to precise determination is, however, the challenge in discriminating between the Soret absorbance for the product (holo-protein) and that for the titrant (hemin). An altogether different approach has been used in this paper to separate contributions made by these components to absorbance values. The pure component spectra and concentration profiles are estimated by a multivariate curve-resolution (MCR) algorithm. This approach has significant advantages over existing methods. First, a more precise determination of Kd can be made as concentration profiles for all three components (apo-protein/holo-protein/hemin) are determined and can be simultaneously fitted to a theoretical-binding model. Second, an absorption spectrum for the holo-protein is calculated. This is a unique advantage of MCR and attractive for investigating proteins in which the nature of heme binding has not, hitherto, been characterised because the holo-protein spectrum provides information on the interaction.
•Method for obtaining heme-binding affinity with advantages over difference absorption.•Multivariate approach for analysis of spectrophotometric titrations.•Distinguishing Soret absorbances for holo-protein and hemin.•Determination of concentration profiles for apo-protein/holo-protein/hemin.•Calculation of absorption spectra for uncharacterised holo-proteins.
In the US, deaths from prescription opioids have quadrupled since 1999, prompting authorities to declare an “opioid abuse” crisis. Rising overdose deaths were attributed to trends in the ...overprescription of opioids, specifically the strength and duration of the initial prescription. We describe educational interventions designed to control healthcare professionals' (HCPs) opioid prescribing in the wake of this crisis. A review of relevant programs for practicing providers, medical residents, and medical students reveals a focus on educational interventions that we describe, borrowing from sociologist John McKinlay's metaphor for public health interventions, as “downstream.” These downstream interventions concentrate on regulating and educating practicing HCPs rather than transforming the training environment for medical students and residents. We draw on theories of behavior change to call for the development of complementary “upstream” educational programs for future practitioners that focus on structural and psychosocial factors and may contribute to more sustainable behavior change outcomes.
•Respiratory viral surveillance in public SARS-CoV-2 testing facilities is feasible.•Sixteen different viruses can be detected using residual eluates.•We detected an atypical seasonal influenza ...pattern with a relatively late onset.•Participant data and public health measures are essential to interpret trends.•It allows for timely detection of viruses that may lead to hospital admissions.
SARS-CoV-2 prevention measures impact the circulation of other respiratory viruses. Surveillance in the network of general practitioners is hampered by widespread testing for SARS-CoV-2 in public testing facilities.
To evaluate integrated community surveillance of SARS-CoV-2 and other respiratory viruses and describe epidemiological trends.
Respiratory surveillance was set up within an existing SARS-CoV-2 public testing facility. Community-dwelling (a)symptomatic persons provided consent for completion of a questionnaire and additional testing on residual material from swabs taken for SARS-CoV-2 RT-PCR (Allplex Seegene). Daily, a random subset was tested for sixteen respiratory viruses by multiplex realtime PCRs (Seegene).
Between October 6th (week 40) 2021 and April 22nd (week 16) 2022, 3,969 subjects were tested. The weekly median age ranged from 23 to 39 years. The prevalence of respiratory symptoms ranged from 98.5% (week 40) to 27.4% (week 1). The prevalence of detection of any respiratory virus (including SARS-CoV-2), ranged from 19.6% in week 49 to 75.3% in week 14. SARS-CoV-2 prevalence ranged from 2.2% (week 40) to 63.3% (week 14). Overall, SARS-CoV-2 was detected most frequently (27.3%), followed by rhinoviruses (14.6%, range 3.5–47.8%) and seasonal coronaviruses (3.7%, range 0–10.4%, mostly 229E and OC43). Influenzavirus was detected in 3.0% of participants from week 6 onwards.
Integrated respiratory viral surveillance within public testing facilities is feasible and informative. Prevalences may be affected by changes in SARS-CoV-2 prevention and testing policies. Population characteristics help to interpret trends over time. Integrated surveillance may inform policymakers and hospitals for adequate response measures during respiratory seasons.
The simulation of viscous free-surface water flow is a subject that has reached a certain maturity and is nowadays used in industrial applications, like the simulation of the flow around ships. While ...almost all methods used are based on the Navier-Stokes equations, the discretisation methods for the water surface differ widely. Many of these highly different methods are being used with success.
We review three of these methods, by describing in detail their implementation in one particular code that is being used in industrial practice. The descriptions concern the principle of the method, numerical details, and the method’s strengths and limitations. For each code, examples are given of its use. Finally, the methods are compared to determine the best field of application for each.
The following surface descretisation methods are reviewed. First, surface fitting/mesh deformation in PARNASSOS, developed by MARIN; the description focuses on the efficient steady-state solution method of this code. Then surface capturing with Volume-of-Fluid in ISIS-CFD, developed by CNRS/Ecole Centrale de Nantes; the main topic of this review are the compressive flux discretisation schemes for the volume fraction that are used in this code. And finally, the Level Set method in SURF, developed by NMRI; this description contains a modified formulation of the Level Set method that is optimised for ship flow computation.
We investigated the positive predictive value (PPV) of a solitary positive immunoglobulin M (IgM) phase II response for the serodiagnosis of acute Q fever detected with either an indirect ...immunofluorescence assay (IFA) or an enzyme-linked immunosorbent assay (ELISA). Initial and follow-up sera from patients suspected of acute Q fever were included if initially only IgM phase II tested positive with IFA in 2008 (n=92), or ELISA in 2009 (n=85). A seroconversion for Q fever was defined as an initial sample being IgG phase II negative but positive in the follow-up sample. The PPV of an initial isolated IgM phase II result detected by IFA or ELISA was 65% and 51%, respectively, and therefore appeared not to adequately predict acute Q fever. For this reason it cannot be used as a diagnostic criterion nor should it be included in public health notification without confirmation with other markers or a follow-up serum sample.
The time is ripe for a comprehensive mission to explore and document Earth's species. This calls for a campaign to educate and inspire the next generation of professional and citizen species ...explorers, investments in cyber-infrastructure and collections to meet the unique needs of the producers and consumers of taxonomic information, and the formation and coordination of a multi-institutional, international, transdisciplinary community of researchers, scholars and engineers with the shared objective of creating a comprehensive inventory of species and detailed map of the biosphere. We conclude that an ambitious goal to describe 10 million species in less than 50 years is attainable based on the strength of 250 years of progress, worldwide collections, existing experts, technological innovation and collaborative teamwork. Existing digitization projects are overcoming obstacles of the past, facilitating collaboration and mobilizing literature, data, images and specimens through cyber technologies. Charting the biosphere is enormously complex, yet necessary expertise can be found through partnerships with engineers, information scientists, sociologists, ecologists, climate scientists, conservation biologists, industrial project managers and taxon specialists, from agrostologists to zoophytologists. Benefits to society of the proposed mission would be profound, immediate and enduring, from detection of early responses of flora and fauna to climate change to opening access to evolutionary designs for solutions to countless practical problems. The impacts on the biodiversity, environmental and evolutionary sciences would be transformative, from ecosystem models calibrated in detail to comprehensive understanding of the origin and evolution of life over its 3.8 billion year history. The resultant cyber-enabled taxonomy, or cybertaxonomy, would open access to biodiversity data to developing nations, assure access to reliable data about species, and change how scientists and citizens alike access, use and think about biological diversity information.
In October 2020, the first case of autochthonous West Nile virus neuroinvasive disease was diagnosed in the Netherlands with a presumed infection in the last week of August. Investigations revealed ...five more cases of local West Nile virus (WNV) infection. The cases resided in a region where WNV was detected in a bird and mosquitoes in August 2020. Molecular analysis was successful for two cases and identified the presence of WNV lineage 2.
Numerical solution of flows that are partially bounded by a freely moving boundary is of great importance in practical applications such as ship hydrodynamics. The usual method for solving steady ...viscous free-surface flow subject to gravitation is alternating time integration of the kinematic condition, and the Navier–Stokes equations subject to the dynamic conditions, until steady state is reached. This paper shows that this time integration approach is often inefficient. It proposes an efficient iterative method for solving the steady free-surface flow problem. The new method relies on a different but equivalent formulation of the free-surface flow problem, involving a so-called quasi free-surface condition. The convergence behavior of the new method is shown to be asymptotically mesh-width independent. Numerical results are presented for two-dimensional flow over an obstacle in a channel. The results confirm the mesh-width independence of the convergence behavior, and comparison of the numerical results with measurements shows good agreement.
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