Lower respiratory tract infection admissions and deaths among children under 5 years in public sector facilities in the Western Cape Province, South Africa, before and during the COVID-19 pandemic (2019 - 2021)

BACKGROUND

The COVID-19 pandemic resulted in the implementation of strict public health and social measures (PHSMs) (including mobility restrictions, social distancing, mask-wearing and hand hygiene), limitations on non-essential healthcare services, and public fear of COVID-19 infection, all of which potentially affected transmission and healthcare use for other diseases such as lower respiratory tract infections (LRTIs).

OBJECTIVE

To determine changes in LRTI hospital admissions and in-facility mortality in children aged <5 years in the Western Cape Province during the pandemic.

METHODS

We conducted a retrospective analysis of LRTI admissions and in-facility deaths from January 2019 to November 2021. We estimated changes in rates and trends of LRTI admissions during the pandemic compared with pre-pandemic period using interrupted time series analysis, adjusting for key characteristics.

RESULTS

There were 36 277 children admitted for LRTIs during the study period, of whom 58% were male and 51% were aged 28 days - 1 year. COVID-19 restrictions were associated with a 13% step reduction in LRTI admissions compared with the pre-COVID-19 period (incidence rate ratio (IRR) 0.87, 95% confidence interval (CI)) 0.80 - 0.94). The average LRTI admission trend increased on average by 2% per month during the pandemic (IRR 1.02, 95% CI 1.02 - 1.04).

CONCLUSIONS

The COVID-19 surges and their associated measures were linked to declining LRTI admissions and in-facility deaths, likely driven by a combination of reduced infectious disease transmission and reduced use of healthcare services, with effects diminishing over time. These findings may inform future pandemic response policies.

Neural network algorithm for detection of erosions and ankylosis on CT of the sacroiliac joints: multicentre development and validation of diagnostic accuracy

OBJECTIVES

To evaluate the feasibility and diagnostic accuracy of a deep learning network for detection of structural lesions of sacroiliitis on multicentre pelvic CT scans.

METHODS

Pelvic CT scans of 145 patients (81 female, 121 Ghent University/24 Alberta University, 18-87 years old, mean 40 ± 13 years, 2005-2021) with a clinical suspicion of sacroiliitis were retrospectively included. After manual sacroiliac joint (SIJ) segmentation and structural lesion annotation, a U-Net for SIJ segmentation and two separate convolutional neural networks (CNN) for erosion and ankylosis detection were trained. In-training validation and tenfold validation testing (U-Net-n = 10 × 58; CNN-n = 10 × 29) on a test dataset were performed to assess performance on a slice-by-slice and patient level (dice coefficient/accuracy/sensitivity/specificity/positive and negative predictive value/ROC AUC). Patient-level optimisation was applied to increase the performance regarding predefined statistical metrics. Gradient-weighted class activation mapping (Grad-CAM++) heatmap explainability analysis highlighted image parts with statistically important regions for algorithmic decisions.

RESULTS

Regarding SIJ segmentation, a dice coefficient of 0.75 was obtained in the test dataset. For slice-by-slice structural lesion detection, a sensitivity/specificity/ROC AUC of 95%/89%/0.92 and 93%/91%/0.91 were obtained in the test dataset for erosion and ankylosis detection, respectively. For patient-level lesion detection after pipeline optimisation for predefined statistical metrics, a sensitivity/specificity of 95%/85% and 82%/97% were obtained for erosion and ankylosis detection, respectively. Grad-CAM++  explainability analysis highlighted cortical edges as focus for pipeline decisions.

CONCLUSIONS

An optimised deep learning pipeline, including an explainability analysis, detects structural lesions of sacroiliitis on pelvic CT scans with excellent statistical performance on a slice-by-slice and patient level.

CLINICAL RELEVANCE STATEMENT

An optimised deep learning pipeline, including a robust explainability analysis, detects structural lesions of sacroiliitis on pelvic CT scans with excellent statistical metrics on a slice-by-slice and patient level.

KEY POINTS

• Structural lesions of sacroiliitis can be detected automatically in pelvic CT scans. • Both automatic segmentation and disease detection yield excellent statistical outcome metrics. • The algorithm takes decisions based on cortical edges, rendering an explainable solution.

Comparison of paediatric infectious disease deaths in public sector health facilities using different data sources in the Western Cape, South Africa (2007-2021)

BACKGROUND

Routinely collected population-wide health data are often used to understand mortality trends including child mortality, as these data are often available more readily or quickly and for lower geographic levels than population-wide mortality data. However, understanding the completeness and accuracy of routine health data sources is essential for their appropriate interpretation and use. This study aims to assess the accuracy of diagnostic coding for public sector in-facility childhood (age < 5 years) infectious disease deaths (lower respiratory tract infections [LRTI], diarrhoea, meningitis, and tuberculous meningitis [TBM]) in routine hospital information systems (RHIS) through comparison with causes of death identified in a child death audit system (Child Healthcare Problem Identification Programme [Child PIP]) and the vital registration system (Death Notification [DN] Surveillance) in the Western Cape, South Africa and to calculate admission mortality rates (number of deaths in admitted patients per 1000 live births) using the best available data from all sources.

METHODS

The three data sources: RHIS, Child PIP, and DN Surveillance are integrated and linked by the Western Cape Provincial Health Data Centre using a unique patient identifier. We calculated the deduplicated total number of infectious disease deaths and estimated admission mortality rates using all three data sources. We determined the completeness of Child PIP and DN Surveillance in identifying deaths recorded in RHIS and the level of agreement for causes of death between data sources.

RESULTS

Completeness of recorded in-facility infectious disease deaths in Child PIP (23/05/2007-08/02/2021) and DN Surveillance (2010-2013) was 70% and 69% respectively. The greatest agreement in infectious causes of death were for diarrhoea and LRTI: 92% and 84% respectively between RHIS and Child PIP, and 98% and 83% respectively between RHIS and DN Surveillance. In-facility infectious disease admission mortality rates decreased significantly for the province: 1.60 (95% CI: 1.37-1.85) to 0.73 (95% CI: 0.56-0.93) deaths per 1000 live births from 2007 to 2020.

CONCLUSION

RHIS had accurate causes of death amongst children dying from infectious diseases, particularly for diarrhoea and LRTI, with declining in-facility admission mortality rates over time. We recommend integrating data sources to ensure the most accurate assessment of child deaths.

Packaging of a Pediatric Weight Management Intervention and Implementation Blueprint for Rural and Micropolitan Communities: The Nebraska CORD 3.0 Project

Pediatric weight management interventions (PWMIs) have resulted in positive changes among family members and, if widely disseminated, could have an impact on pediatric weight management in rural communities. The purpose of this article is to describe a backward design approach taken to create an online packaged program and implementation blueprint for building healthy families (BHF), an effective PWMI for implementation in rural communities. The backward design process included the identification of end users: primary (facilitators to be trained through the packaged program and implementation blueprint), secondary (researchers and evaluators), terminal (caregivers and children impacted by PWMI participation), tertiary (community support organizations, funding agency promoting widespread PWMI, and payors), as well as, key outcomes for respective end user groups based on the reach, effectiveness, adoption, implementation, and maintenance (RE-AIM) framework. This process resulted in the BHF Online Training Resources and Program package and implementation blueprint that included a modular approach encompassing the interplay of training modules for program facilitators, knowledge checks to ensure mastery of program components, recruitment resources for school and clinical settings, all program materials, embedded fidelity assessments for quality assurance, and a data portal to track participant success. Next steps include preliminary product testing with potential facilitators and a type 3 effectiveness implementation trial to determine the utility of the BHF Online Training Resources and Program package with and without participation in a learning collaborative to support implementation and sustainability.

Metabolic Support for Elderly, Severe COVID-19 Patients With Acute Respiratory Failure: A Case Series

Objectives

Severe COVID-19 (SvC19) is a syndrome of acute lung injury, respiratory failure, cytokine storm, distributive shock, multi-system organ failure and high mortality. SvC19 disproportionately impacts the elderly, who are also at risk for micronutrient deficiency. After observing a beneficial response to micronutrient repletion (MR) in a 69 year-old male with SvC19, we hypothesized that nutritional deficiencies were linked to the pathogenesis and that correcting them could be beneficial. In this report we detail a case series of 18 older patients with SvC19 treated with MR.

Methods

All patients had SvC19 requiring mechanical ventilation, elevated levels of CRP, D-dimer and neutrophil to lymphocyte ratio. MR consisted of daily parenteral ascorbate, thiamine, pyridoxine and multivitamins, as well as daily ergocalciferol, zinc and carnitine via nasogastric tube.

Results

The average age was 63.3 years. Six patients were male, 12 female. Disease severity was comparable based on SOFA score. A partial response was observed in 10 of the 18 patients (55.5%). Six (33.3%) were able to wean off blood pressure support. Five (27.7%) had improvement in gas exchange. Four (22.2) were able to wean off ventilator support. Three patients (37.5%) showed improvement in renal dysfunction.

Conclusions

MR shows potential promise as an adjunctive treatment for severe COVID-19, particularly in older patients or those with chronic illness in whom nutritional deficiencies are more probable.

Funding Sources

None

Unexpected air quality impacts from implementation of green infrastructure in urban environments: A Kansas City case study

Green infrastructure (GI) implementation can benefit an urban environment by reducing the impacts of urban stormwater on aquatic ecosystems and human health. However, few studies have systematically analyzed the biophysical effects on regional meteorology and air quality that are triggered by changes in the urban vegetative coverage. In this study we use a state-of-the-art high-resolution air quality model to simulate the effects of a hypothetically feasible vegetation-focused GI implementation scenario in Kansas City, MO/KS on regional meteorology and air quality. Full year simulations are conducted for both the base case and GI land use scenarios using two different land surface models (LSMs) schemes inside the meteorological model. While the magnitudes of the changes in air quality due to the GI implementation differ using the two LSMs, the model outputs consistently showed increases in summertime PM_2.5 (1.1 μg m^-3, approximately 10% increase using NOAH LSM), which occurred mostly during the night and arose from the primary components, due to the cooler surface temperatures and the decreased planetary boundary layer height (PBLH). Both the maximum daily 8-hour average ozone and 1 h daily maximum O₃ during summertime, decreased over the downtown areas (maximum decreases of 0.9 and 1.4 ppbv respectively). The largest ozone decreases were simulated to happen during the night, mainly caused by the titration effect of increased NO_x concentration from the lower PBLH. These results highlight the region-specific non-linear process feedback from GI on regional air quality, and further demonstrate the need for comprehensive coupled meteorological-air quality modeling systems and necessity of accurate land surface model for studying these impacts.

Bayesian pooling versus sequential integration of small preclinical trials: a comparison within linear and nonlinear modeling frameworks

Bayesian sequential integration is an appealing approach in drug development, as it allows to recursively update posterior distributions as soon as new data become available, thus considerably reducing the computation time. However, preclinical trials are often characterized by small sample sizes, which may affect the estimation process during the first integration steps, particularly when complex PK-PD models are used. In this case, sequential integration would not be practicable, and trials should be pooled together. This work is aimed at comparing simple Bayesian pooling with sequential integration through a simulation study. The two techniques are compared under several scenarios using linear as well as nonlinear models. The results of our simulation study encourage the use of Bayesian sequential integration with linear models. However, in the case of nonlinear models several caveats arise. This paper outlines some important recommendations and precautions in that respect.

The development of a theory-based eHealth app prototype to promote oral health during prenatal care visits

Poor maternal oral health during pregnancy is associated with adverse maternal and child outcomes, including preterm birth and early childhood caries. Subsequently, professional associations have developed prenatal oral health guidelines, but significant gaps exist in implementing guidelines into clinical practice. The purpose of this study was to develop and test the usability of an innovative, theory-driven, eHealth application ("app") to facilitate prenatal providers' (nurse practitioners and midwives) implementation of oral health promotion during prenatal care visits. App development was guided by previous research, an integrated conceptual framework, Scientific Advisory Board input, and consumer-engaged iterative processes utilizing mixed-methods (observations, surveys, in-depth interviews) among providers (n = 4) during 10 unique prenatal care visits at a federally qualified health care center. Triangulation of quantitative and qualitative data analysis produced descriptive frequencies and salient themes. Concepts and principles from the following theoretical frameworks informed intervention development and testing: Consolidated Framework for Implementation Research; Information-Motivation-Behavioral Skills Model; Health Literacy; and Brief Motivational Interviewing. Overall, providers reported the app was effective at providing the information, motivation, and behavioral skills needed to integrate oral health promotion (e.g., easy to use; provided cues to action via scripts and tailored education; and documented findings into the patient's record). Although providers reported high usability, time constraints and detailed patient counseling scripts were identified areas for improvement. Findings suggest that the eHealth app could serve as an innovative mechanism to assist providers in implementing the prenatal oral health guidelines into practice. Future research is needed to continue app development efforts and to determine efficacy and effectiveness in practice settings.

CSF1R inhibitor JNJ-40346527 attenuates microglial proliferation and neurodegeneration in P301S mice

Neuroinflammation and microglial activation are significant processes in Alzheimer's disease pathology. Recent genome-wide association studies have highlighted multiple immune-related genes in association with Alzheimer's disease, and experimental data have demonstrated microglial proliferation as a significant component of the neuropathology. In this study, we tested the efficacy of the selective CSF1R inhibitor JNJ-40346527 (JNJ-527) in the P301S mouse tauopathy model. We first demonstrated the anti-proliferative effects of JNJ-527 on microglia in the ME7 prion model, and its impact on the inflammatory profile, and provided potential CNS biomarkers for clinical investigation with the compound, including pharmacokinetic/pharmacodynamics and efficacy assessment by TSPO autoradiography and CSF proteomics. Then, we showed for the first time that blockade of microglial proliferation and modification of microglial phenotype leads to an attenuation of tau-induced neurodegeneration and results in functional improvement in P301S mice. Overall, this work strongly supports the potential for inhibition of CSF1R as a target for the treatment of Alzheimer's disease and other tau-mediated neurodegenerative diseases.

Bayesian sequential integration within a preclinical pharmacokinetic and pharmacodynamic modeling framework: Lessons learned

The present manuscript aims to discuss the implications of sequential knowledge integration of small preclinical trials in a Bayesian pharmacokinetic and pharmacodynamic (PK-PD) framework. While, at first sight, a Bayesian PK-PD framework seems to be a natural framework to allow for sequential knowledge integration, the scope of this paper is to highlight some often-overlooked challenges while at the same time providing some guidances in the many and overwhelming choices that need to be made. Challenges as well as opportunities will be discussed that are related to the impact of (1) the prior specification, (2) the choice of random effects, (3) the type of sequential integration method. In addition, it will be shown how the success of a sequential integration strategy is highly dependent on a carefully chosen experimental design when small trials are analyzed.

Bayesian knowledge integration for an in vitro-in vivo correlation model

The primary goal of "in vitro-in vivo correlation" (IVIVC) is the reliable prediction of the in vivo serum concentration-time course, based on the in vitro drug dissolution or release profiles. IVIVC methods are particularly appropriate for formulations that are released over an extended period of time or with a lag in absorption and may support approving a change in formulation of a drug without additional bioequivalence trials in human subjects. Most of the current IVIVC models are assessed using frequentist methods, such as linear regression, based on averaged data and entail complex and potentially unstable mathematical deconvolution. The proposed IVIVC approach includes (a) a nonlinear-mixed effects model for the in vitro release data; (b) a population pharmacokinetic (PK) compartment model for the in vivo immediate release (IR) data; and (c) a system of ordinal differential equations (ODEs), containing the submodels (a) and (b), which approximates and predicts the in vivo controlled release (CR) data. The innovation in this paper consists of splitting the parameter space between submodels (a) and (b) versus (c). Subsequently, the uncertainty on these parameters is accounted for using a Bayesian framework, that is estimates from the first two submodels serve as priors for the Bayesian hierarchical third submodel. As such, the Bayesian method explained ensures a natural integration and transfer of knowledge between various sources of information, balancing possible differences in sample size and parameter uncertainty of in vitro and in vivo studies. Consequently, it is a very flexible approach yielding results for a broad range of data situations. The application of the method is demonstrated for a transdermal patch (TD).

A proposal for a new PhD level curriculum on quantitative methods for drug development

This paper provides an overview of "Improving Design, Evaluation and Analysis of early drug development Studies" (IDEAS), a European Commission-funded network bringing together leading academic institutions and small- to large-sized pharmaceutical companies to train a cohort of graduate-level medical statisticians. The network is composed of a diverse mix of public and private sector partners spread across Europe, which will host 14 early-stage researchers for 36 months. IDEAS training activities are composed of a well-rounded mixture of specialist methodological components and generic transferable skills. Particular attention is paid to fostering collaborations between researchers and supervisors, which span academia and the private sector. Within this paper, we review existing medical statistics programmes (MSc and PhD) and highlight the training they provide on skills relevant to drug development. Motivated by this review and our experiences with the IDEAS project, we propose a concept for a joint, harmonised European PhD programme to train statisticians in quantitative methods for drug development.

Identifying Implementation Science Characteristics for a Prenatal Oral Health eHealth Application

Background. Oral health is a significant public health issue; yet barriers to implementing the prenatal oral health guidelines into practice remain. This formative research aimed to identify key implementation science characteristics to inform the development of an eHealth application (app) to assist providers in implementing the prenatal oral health guidelines during prenatal visits. Method. Guided by the Consolidated Framework for Implementation Research, the clinic's infrastructure, workflow, and contextual factors were assessed via clinic observation, technology assessment, prenatal provider interviews (n = 4), clinic staff interviews (n = 8), and two focus groups with oral health providers (n = 16). Results. System-level factors influencing future implementation were identified regarding structural characteristic, networks/communication, culture, external policy/incentives, relative advantage, complexity, design quality/packaging, knowledge/beliefs, and personal attributes. Discussion. Findings provided vital information and will directly inform the design and implementation of an eHealth app that aims to facilitate the translation of the interprofessional prenatal oral health guidelines into clinical prenatal oral health practices.

Young to Middle-Aged Dogs with High Amyloid-β Levels in Cerebrospinal Fluid are Impaired on Learning in Standard Cognition tests

Understanding differences in Alzheimer’s disease biomarkers before the pathology becomes evident can contribute to an improved understanding of disease pathogenesis and treatment. A decrease in amyloid-β (Aβ)₄₂ in cerebrospinal fluid (CSF) is suggested to be a biomarker for Aβ deposition in brain. However, the relevance of CSF Aβ levels prior to deposition is not entirely known. Dogs are similar to man with respect to amyloid-β protein precursor (AβPP)-processing, age-related amyloid plaque deposition, and cognitive dysfunction. In the current study, we evaluated the relation between CSF Aβ₄₂ levels and cognitive performance in young to middle-aged dogs (1.5–7 years old). Additionally, CSF sAβPPα and sAβPPβ were measured to evaluate AβPP processing, and CSF cytokines were measured to determine the immune status of the brain. We identified two groups of dogs showing consistently low or high CSF Aβ₄₂ levels. Based on prior studies, it was assumed that at this age no cerebral amyloid plaques were likely to be present. The cognitive performance was evaluated in standard cognition tests. Low or high Aβ concentrations coincided with low or high sAβPPα, sAβPPβ, and CXCL-1 levels, respectively. Dogs with high Aβ concentrations showed significant learning impairments on delayed non-match to position (DNMP), object discrimination, and reversal learning compared to dogs with low Aβ concentrations. Our data support the hypothesis that high levels of CSF Aβ in dogs coincide with lower cognitive performance prior to amyloid deposition. Further experiments are needed to investigate this link, as well as the relevance with respect to Alzheimer’s disease pathology progression.

Likely Transiting Exocomets Detected By Kepler

We present the first good evidence for exocomet transits of a host star in continuum light in data from the Kepler mission. The Kepler star in question, KIC 3542116, is of spectral type F2V and is quite bright at Kp = 10. The transits have a distinct asymmetric shape with a steeper ingress and slower egress that can be ascribed to objects with a trailing dust tail passing over the stellar disk. There are three deeper transits with depths of ≃ 0.1% that last for about a day, and three that are several times more shallow and of shorter duration. The transits were found via an exhaustive visual search of the entire Kepler photometric data set, which we describe in some detail. We review the methods we use to validate the Kepler data showing the comet transits, and rule out instrumental artefacts as sources of the signals. We fit the transits with a simple dust-tail model, and find that a transverse comet speed of ∼35-50 km s-1 and a minimum amount of dust present in the tail of ∼ 1016 g are required to explain the larger transits. For a dust replenishment time of ∼10 days, and a comet lifetime of only ∼300 days, this implies a total cometary mass of ≳ 3 × 1017 g, or about the mass of Halley's comet. We also discuss the number of comets and orbital geometry that would be necessary to explain the six transits detected over the four years of Kepler prime-field observations. Finally, we also report the discovery of a single comet-shaped transit in KIC 11084727 with very similar transit and host-star properties.

Critical care in acute ischemic stroke

Most ischemic strokes are managed on the ward or on designated stroke units. A significant proportion of patients with ischemic stroke require more specialized care. Several studies have shown improved outcomes for patients with acute ischemic stroke when neurocritical care services are available. Features of acute ischemic stroke patients requiring intensive care unit-level care include airway or respiratory compromise; large cerebral or cerebellar hemisphere infarction with swelling; infarction with symptomatic hemorrhagic transformation; infarction complicated by seizures; and a large proportion of patients require close management of blood pressure after thrombolytics. In this chapter, we discuss aspects of acute ischemic stroke care that are of particular relevance to a neurointensivist, covering neuropathology, neurodiagnostics and imaging, blood pressure management, glycemic control, temperature management, and the selection and timing of antithrombotics. We also focus on the care of patients who have received intravenous thrombolysis or mechanical thrombectomy. Complex clinical decision making in decompressive hemicraniectomy for hemispheric infarction and urgent management of basilar artery thrombosis are specifically addressed.

Advancing the framework for considering the effects of climate change on worker safety and health

In 2009, a preliminary framework for how climate change could affect worker safety and health was described. That framework was based on a literature search from 1988-2008 that supported seven categories of climate-related occupational hazards: (1) increased ambient temperature; (2) air pollution; (3) ultraviolet radiation exposure; (4) extreme weather; (5) vector-borne diseases and expanded habitats; (6) industrial transitions and emerging industries; and (7) changes in the built environment. This article reviews the published literature from 2008-2014 in each of the seven categories. Additionally, three new topics related to occupational safety and health are considered: mental health effects, economic burden, and potential worker safety and health impacts associated with the nascent field of climate intervention (geoengineering). Beyond updating the literature, this article also identifies key priorities for action to better characterize and understand how occupational safety and health may be associated with climate change events and ensure that worker health and safety issues are anticipated, recognized, evaluated, and mitigated. These key priorities include research, surveillance, risk assessment, risk management, and policy development. Strong evidence indicates that climate change will continue to present occupational safety and health hazards, and this framework may be a useful tool for preventing adverse effects to workers.

Development of iBsafe: A Collaborative, Theory-based Approach to Creating a Mobile Game Application for Child Safety

Unintentional injury is a leading cause of death worldwide, and the number one cause of child death in the United States. The American Academy of Pediatrics promotes safety recommendations to decrease child injury risk, however the majority of educational programs delivering these strategies are school-based or in community campaigns. Mobile technology provides an opportune platform to deliver pediatric injury prevention programs given its massive global reach and underrepresentation within the current mobile health market. This paper describes the development of iBsafe, a novel mobile safety game application designed to prevent injury in 5- to 6- year old children. Our multidisciplinary team utilized a step-wise approach to create an innovative child game application which is based in behavioral theory and promotes evidence-based safety recommendations. Results and future directions for iBsafe aim to interactively educate children on how to be safe and ultimately improve their safety behaviors.

Comparison of two different methods for measurement of amyloid-β peptides in cerebrospinal fluid after BACE1 inhibition in a dog model

Beta-secretase is the first cleavage enzyme of amyloid-β protein precursor (AβPP) in the amyloidogenic pathway, leading to the formation of the plaque forming Amyloid-β (Aβ)1-42 peptide. BACE (beta-site AβPP cleaving enzyme) 1 inhibition is therefore considered to be a promising disease modifying therapy for Alzheimer's disease. An early assessment of the in vivo activity of BACE inhibitors was done in dogs since AβPP processing is the same as in humans and this species easily enables longitudinal cerebrospinal fluid (CSF) sampling. Aβ changes in CSF compared to baseline are used to evaluate target engagement of the compounds. Levels of Aβ1-37, Aβ1-38, Aβ1-40, and Aβ1-42 in CSF are measured with immunoassay (Mesoscale electrochemiluminescence technology) and with an ultra high-performance liquid chromatography mass spectrometry (UPLC-MS/MS). Two experimental BACE inhibitors were evaluated. With the immunoassay, a dose dependent decrease is observed for all four Aβ peptides. Measurements with the UPLC-MS/MS are in line with the immunoassay for Aβ1-37, Aβ1-38, and Aβ1-40, however, for Aβ1-42, differences are sometimes observed when comparing to changes seen in the other peptides with UPLC-MS/MS and with immunoassay results. Generally lower concentrations are measured with immunoassay. The reason for these differences is still unknown. Aβ1-42 is more prone to form aggregates compared to the other peptides. One hypothesis could be that while the immunoassay only measures free Aβ, bound and aggregated Aβ peptides are at least partially dissolved with the UPLC-MS/MS method, since acetonitrile is added to the CSF samples. This increases variability in the concentration of Aβ peptide measured with UPLC-MS/MS, especially for Aβ1-42, potentially masking the compound effect on Aβ1-42 levels.

Strong absorption and selective emission from engineered metals with dielectric coatings

We demonstrate strong-to-perfect absorption across a wide range of mid-infrared wavelengths (5-12µm) using a two-layer system consisting of heavily-doped silicon and a thin high-index germanium dielectric layer. We demonstrate spectral control of the absorption resonance by varying the thickness of the dielectric layer. The absorption resonance is shown to be largely polarization-independent and angle-invariant. Upon heating, we observe selective thermal emission from our materials. Experimental data is compared to an analytical model of our structures with strong agreement.

Reporter gene expression from LTR-circles as tool to identify HIV-1 integrase inhibitors

Early HIV-1 integrase inhibitors, such as compounds containing a β-diketo acid moiety, were identified by extensive high-throughput screening campaigns. Traditionally, in vitro biochemical assays, measuring the catalytic activities of integrase, have been used for this purpose. However, these assays are confounded by the absence of cellular processes or cofactors that play a role in the integration of HIV-1 DNA in the cellular genome. In contrast to regular cell-based virus inhibition assays, which targets all steps of the viral replication cycle, a novel cellular screening assays was developed to enable the specific identification of integrase inhibitors, employing a readout that is linked with the inhibition of integrase activity. Therefore, a HIV-1 lentiviral vector equipped with the enhanced green fluorescent protein (eGFP) reporter gene was used to detect expression from extrachromosomal viral DNA (1- or 2-long terminal repeat circles), formed when integration of vector DNA into the cellular genome is prevented by an integrase inhibitor. In this assay, eGFP expression from the low residual level of transcriptional activity of extrachromosomal DNA was measured via high-throughput flow cytometry. An algorithm for analysis of eGFP expression histograms enabled the specific identification of integrase inhibitors. This assay is amenable for high throughput screening to identify inhibitors of HIV-1 integrase.

Brivaracetam disposition in renal impairment

Brivaracetam is a novel high-affinity SV2A ligand currently in clinical development for epilepsy. The objective was to characterize its disposition in patients with renal impairment. A single oral dose of 200 mg brivaracetam was administered to 9 patients with severe renal impairment not requiring dialysis (creatinine clearance <15 mL/min, n = 6; 15-29 mL/min, n = 3) and 9 matched healthy controls. Plasma and urinary concentrations of brivaracetam and 3 pharmacologically inactive metabolites (acid, hydroxy, and hydroxyacid) were determined up to 72 hours postdose, and noncompartmental pharmacokinetic parameters were derived. The C(max) of brivaracetam was unchanged relative to healthy controls, whereas AUC was slightly increased (mean ratio, 1.21; 90% confidence interval, 1.01-1.45). Nonrenal and renal clearances of brivaracetam decreased from 47 and 4.5 to 41 and 1.7 mL/min/1.73 m(2). Exposure to the acid, hydroxy, and hydroxyacid metabolites was markedly increased: C(max) by 2.4-, 2.0-, and 11.7-fold and AUC by 3.2-, 4.1-, and 21.5-fold. Renal clearance of these rapidly cleared metabolites was decreased 10-fold in patients with severe renal impairment. Nonclinical toxicology studies concluded to the absence of safety issues related to the increased levels of metabolites. These observations suggest that dose adjustment of brivaracetam should not be required at any stage of renal dysfunction.

A latent pharmacokinetic time profile to model dose-response survival data

The accelerating rotarod test is a preclinical pharmacodynamic test to assess the effect of a treatment on an animal's motor coordination. Two models are proposed to analyze the dose-response time-to-event data that typically result from such experiments: (1) a linear regression model and (2) an E(max) model with latent drug concentration at the site of action. Both cope with the survival character of the data. The latter model allows a direct comparison of compounds, but raises the question of whether the study design would benefit from the inclusion of additional mice for plasma concentration sampling on the one hand or whether additional time-to-event data without plasma concentration sampling should be ascertained from these additional mice on the other hand. A simulation study explores the impact on operational characteristics of this change of study design.

The p21-activated kinase is required for neuronal migration in the cerebral cortex

The normal formation and function of the mammalian cerebral cortex depend on the positioning of its neurones, which occurs in a highly organized, layer-specific manner. The correct morphology and movement of neurones rely on synchronized regulation of their actin filaments and microtubules. The p21-activated kinase (Pak1), a key cytoskeletal regulator, controls neuronal polarization, elaboration of axons and dendrites, and the formation of dendritic spines. However, its in vivo role in the developing nervous system is unclear. We have utilized in utero electroporation into mouse embryo cortices to reveal that both loss and gain of Pak1 function affect radial migration of projection neurones. Overexpression of hyperactivated Pak1 predominantly caused neurones to arrest in the intermediate zone (IZ) with apparently misoriented and disorganized leading projections. Loss of Pak1 disrupted the morphology of migrating neurones, which accumulated in the IZ and deep cortical layers. Unexpectedly, a significant number of neurones with reduced Pak1 expression aberrantly entered into the normally cell-sparse marginal zone, suggesting their inability to cease migrating that may be due to their impaired dissociation from radial glia. Our findings reveal the in vivo importance of temporal and spatial regulation of the Pak1 kinase during key stages of cortical development.

Liposome-encapsulated antigens induce a protective CTL response against Listeria monocytogenes independent of CD4+ T cell help

Protection against intracellular pathogens is usually mediated by cytotoxic T lymphocytes (CTL). Induction of a protective CTL response for vaccination purposes has proven difficult because of the limited access of protein antigens or attenuated pathogens to the MHC class I presentation pathway. We show here that pH-sensitive PE/CHEMS liposomes can be used as a vehicle to efficiently deliver intact proteins for presentation by MHC class I. Mice immunized with listerial proteins encapsulated in such liposomes launched a strong CTL response and were protected against a subsequent challenge with L. monocytogenes. Remarkably, the CTL response was induced independently of detectable CD4(+) T cell help.

Evaluation of brivaracetam, a novel SV2A ligand, in the photosensitivity model

OBJECTIVE

To assess the activity of brivaracetam, a novel SV2A ligand, in the photosensitivity model as a proof-of-principle of efficacy in patients with epilepsy.

METHODS

A subject-blind placebo-controlled study in patients with photosensitive epilepsy was performed to investigate the effect of single-dose brivaracetam (10, 20, 40, or 80 mg) on photosensitive responses. Each patient was exposed to intermittent photic stimulation that evoked a generalized photoparoxysmal EEG response. Individual standard photosensitivity ranges (SPRs) were recorded post-placebo (day -1) and post-brivaracetam until return to baseline (day 1 to 3). Plasma concentrations of brivaracetam and any concomitant antiepileptic drugs were determined.

RESULTS

Of the 18 evaluable patients, none achieved SPR abolishment post-placebo, whereas 14 (78%) achieved complete abolishment post-brivaracetam. Decrease in SPR was seen in 8 patients (44%) post-placebo compared to 17 (94%) post-brivaracetam. Duration of response was twice as long post-brivaracetam 80 mg (59.5 hours) compared with lower doses, although the overall effect was not dose-dependent. Time to maximal photosensitive response was dose-related with the shortest time interval observed at the highest dose (0.5 hours post-brivaracetam 80 mg). The area under the effect curve (SPR change from pre-dose vs time) appeared linearly correlated with the area under the plasma concentration curve. Brivaracetam was well tolerated. The most common adverse events were dizziness and somnolence.

CONCLUSIONS

Our findings show that brivaracetam clearly suppresses generalized photoparoxysmal EEG response. As such, investigations of the antiepileptic properties and tolerability of brivaracetam are warranted in further clinical studies of patients with epilepsy.