Publications by authors named "E C Brown"

6,095 Publications

Modification of maternal late pregnancy sleep position: a survey evaluation of a New Zealand public health campaign.

BMJ Open 2021 May 11;11(5):e047681. Epub 2021 May 11.

Department of Obstetrics and Gynaecology, University of Auckland, Auckland, New Zealand.

Introduction: A 'Sleep-On-Side When Baby's Inside' public health campaign was initiated in New Zealand in 2018. This was in response to evidence that maternal supine going-to-sleep position was an independent risk factor for stillbirth from 28 weeks' gestation. We evaluated the success of the campaign on awareness and modification of late pregnancy going-to-sleep position through nationwide surveys.

Methods And Analysis: Two web-based cross-sectional surveys were conducted over 12 weeks in 2019-2020 in a sample of (1) pregnant women ≥28 weeks, primary outcome of going-to-sleep position; and (2) health professionals providing pregnancy care, primary outcome of knowledge of going-to-sleep position and late stillbirth risk. Univariable logistic regression was performed to identify factors associated with supine going-to-sleep position.

Discussion: The survey of pregnant women comprised 1633 eligible participants. Going-to-sleep position last night was supine (30, 1.8%), non-supine (1597, 97.2%) and no recall (16, 1.0%). Supine position had decreased from 3.9% in our previous New Zealand-wide study (2012-2015). Most women (1412, 86.5%) had received sleep-on-side advice with no major resultant worry (1276, 90.4%). Two-thirds (918, 65.0%) had changed their going-to-sleep position based on advice, with most (611 of 918, 66.5%) reporting little difficulty. Supine position was associated with Māori (OR 5.05, 95% CI 2.10 to 12.1) and Asian-non-Indian (OR 4.20, 95% CI 1.27 to 13.90) ethnicity; single (OR 10.98, 95% CI 4.25 to 28.42) and cohabitating relationship status (OR 2.69, 95% CI 1.09 to 6.61); hospital-based maternity provider (OR 2.55, 95% CI 1.07 to 6.10); education overseas (OR 3.92, 95% CI 1.09 to 14.09) and primary-secondary level (OR 2.80, 95% CI 1.32 to 6.08); and not receiving sleep-on-side advice (OR 6.70, 95% CI 3.23 to 13.92). The majority of health professionals (709 eligible participants) reported awareness of supine going-to-sleep position and late stillbirth risk (543, 76.6%).

Conclusion: Most pregnant women had received and implemented sleep-on-side advice without major difficulty or concern. Some groups of women may need a tailored approach to acquisition of going-to-sleep position information.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/bmjopen-2020-047681DOI Listing
May 2021

A Generalized Potentiostat Adaptor for Multiplexed Electroanalysis.

Anal Chem 2021 May 12. Epub 2021 May 12.

Department of Chemistry, The University of North Carolina at Chapel Hill, 133 South Road, Chapel Hill, North Carolina 27599, United States.

Electrochemical measurements over an array of electrodes may be accomplished with one of three potentiostat architectures: a single-channel device which averages the signal from a number of interconnected electrodes, a multichannel device with dedicated circuits for each electrode, or a single-channel device with a multiplexer interface to isolate the signal from specific electrodes. Of these three architectures, the use of a multiplexer interface is best suited to facilitate measurements over individual electrodes without the need for large numbers of dedicated potentiostat channels. We present a versatile strategy for the development of flexible printed circuit (FPC) electrode arrays with accompanying multiplexing hardware to interface with single-channel potentiostats. The FPC array was fabricated with 78 individually addressable 0.3 mm diameter gold working electrodes and characterized using optical and scanning electron microscopy, energy dispersive spectroscopy, profilometry, impedance spectroscopy, and cyclic voltammetry to investigate the morphology, elemental composition, height profile, impedance characteristics, and electrochemical response, respectively. Interfacing the FPC array via a simple connector with three 32-channel ADG731 multiplexers permitted electrochemical measurements using single-channel commercial potentiostats. Voltammetric experiments were conducted to demonstrate the reliability, stability, and reproducibility of the FPC array and interfacing hardware. The combination of these devices represents an accessible hardware platform with robust, functionalizable electrodes, a simple connection interface with commercial potentiostats, and a low cost through the use of off-the-shelf components. Our reported strategy holds great promise to facilitate multiplexed electroanalysis in next-generation sensors to increase statistical sample size and multianalyte detection capabilities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.analchem.0c05299DOI Listing
May 2021

Glutamate signaling via the AMPAR subunit GluR4 regulates oligodendrocyte progenitor cell migration in the developing spinal cord.

J Neurosci 2021 May 7. Epub 2021 May 7.

Department of Biology, University of Virginia, Charlottesville, VA 22904, USA

Oligodendrocyte progenitor cells (OPC) are specified from discrete precursor populations during gliogenesis and migrate extensively from their origins, ultimately distributing throughout the brain and spinal cord during early development. Subsequently, a subset of OPCs differentiates into mature oligodendrocytes, which myelinate axons. This process is necessary for efficient neuronal signaling and organism survival. Previous studies have identified several factors that influence OPC development, including excitatory glutamatergic synapses that form between neurons and OPCs during myelination. However, little is known about how glutamate signaling affects OPC migration prior to myelination. In this study, we use time-lapse imaging in zebrafish in conjunction with genetic and pharmacological perturbation to investigate OPC migration and myelination when the GluR4A ionotropic glutamate receptor subunit is disrupted. In our studies, we observed that mutant embryos and larvae displayed abnormal OPC migration and altered dorsoventral distribution in the spinal cord. Genetic mosaic analysis confirmed that these effects were cell-autonomous, and we identified that voltage-gated calcium channels were downstream of glutamate receptor signaling in OPCs and could rescue the migration and myelination defects we observed when glutamate signaling was perturbed. These results offer new insights into the complex system of neuron-OPC interactions and reveal a cell-autonomous role for glutamatergic signaling in OPCs during neural development.The migration of oligodendrocyte progenitor cells (OPC) is an essential process during development that leads to uniform oligodendrocyte distribution and sufficient myelination for central nervous system function. Here we demonstrate that the AMPA receptor subunit GluR4A is an important driver of OPC migration and that activated voltage-gated calcium channels are downstream of glutamate receptor signaling in mediating this migration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1523/JNEUROSCI.2562-20.2021DOI Listing
May 2021

Update on pediatric testicular germ cell tumors.

J Pediatr Surg 2021 Apr 15. Epub 2021 Apr 15.

Department of Surgery, Mott Children's Hospital, University of Michigan, Ann Arbor, MI, United States.

Background: Testicular germ cell tumors are uncommon tumors that are encountered by pediatric surgeons and urologists and require a knowledge of appropriate contemporary evaluation and surgical and medical management.

Method: A review of the recommended diagnostic evaluation and current surgical and medical management of children and adolescents with testicular germ cell tumors based upon recently completed clinical trials was performed and summarized in this article.

Results: In this summary of childhood and adolescent testicular germ cell tumors, we review the initial clinical evaluation, surgical and medical management, risk stratification, results from recent prospective cooperative group studies, and clinical outcomes. A summary of recently completed clinical trials by pediatric oncology cooperative groups is provided, and best surgical practices are discussed.

Conclusions: Testicular germ cell tumors in children are rare tumors. International collaborations, data-sharing, and enrollment of patients at all stages and risk classifications into active clinical trials will enhance our knowledge of these rare tumors and most importantly improve outcomes of patients with testicular germ cell tumors.

Level Of Evidence: This is a review article of previously published and referenced level 1 and 2 studies, but also includes expert opinion level 5, represented by the American Pediatric Surgical Association Cancer Committee.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jpedsurg.2021.04.001DOI Listing
April 2021

Chemical Screen for Vancomycin Antagonism Uncovers Probes of the Gram-Negative Outer Membrane.

ACS Chem Biol 2021 May 11. Epub 2021 May 11.

Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8N 3Z5, Canada.

The outer membrane of Gram-negative bacteria is a formidable permeability barrier which allows only a small subset of chemical matter to penetrate. This outer membrane barrier can hinder the study of cellular processes and compound mechanism of action, as many compounds including antibiotics are precluded from entry despite having intracellular targets. Consequently, outer membrane permeabilizing compounds are invaluable tools in such studies. Many existing compounds known to perturb the outer membrane also impact inner membrane integrity, such as polymyxins and their derivatives, making these probes nonspecific. We performed a screen of ∼140 000 diverse synthetic compounds, for those that antagonized the growth inhibitory activity of vancomycin at 15 °C in , to enrich for chemicals capable of perturbing the outer membrane. This led to the discovery that liproxstatin-1, an inhibitor of ferroptosis in human cells, and MAC-0568743, a novel cationic amphiphile, could potentiate the activity of large-scaffold antibiotics with low permeation into Gram-negative bacteria at 37 °C. Liproxstatin-1 and MAC-0568743 were found to physically disrupt the integrity of the outer membrane through interactions with lipopolysaccharide in the outer leaflet of the outer membrane. We showed that these compounds selectively disrupt the outer membrane while minimally impacting inner membrane integrity, particularly at the concentrations needed to potentiate Gram-positive-targeting antibiotics. Further exploration of these molecules and their structural analogues is a promising avenue for the development of outer membrane specific probes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acschembio.1c00179DOI Listing
May 2021