Electrophoresis of a small sphere in a cylinder of finite length.

The pressure due to electrophoretic motion of a charged colloidal sphere in a fluid-filled circular cylinder is determined in the limit in which the sphere radius is small compared with that of the cylinder. If the ends of the cylinder are open, pressure-driven Poiseuille flow occurs, but the magnitude of this flow is shown to be small when the cylinder is long compared to its radius. It is concluded that the flow has little effect upon electrophoretic velocities, unlike when the diameter of the sphere is comparable to that of the cylinder in which case the Poiseuille flow increases electrophoretic velocities and creates long-range interactions between spheres.

Cell diversity and network dynamics in photosensitive human brain organoids.

In vitro models of the developing brain such as three-dimensional brain organoids offer an unprecedented opportunity to study aspects of human brain development and disease. However, the cells generated within organoids and the extent to which they recapitulate the regional complexity, cellular diversity and circuit functionality of the brain remain undefined. Here we analyse gene expression in over 80,000 individual cells isolated from 31 human brain organoids. We find that organoids can generate a broad diversity of cells, which are related to endogenous classes, including cells from the cerebral cortex and the retina. Organoids could be developed over extended periods (more than 9 months), allowing for the establishment of relatively mature features, including the formation of dendritic spines and spontaneously active neuronal networks. Finally, neuronal activity within organoids could be controlled using light stimulation of photosensitive cells, which may offer a way to probe the functionality of human neuronal circuits using physiological sensory stimuli.

The lateral electric force on an off-axis sphere in a circular cylinder.

The electrophoretic velocity of a sphere within a liquid-filled circular cylinder in a direction parallel to the cylinder axis has been studied by Yariv and Brenner (Phys. Fluids 2002, 14, 3354-3357; SIAM J. Appl. Math. 2003, 64, 423-441). We use their analyses of the electric field in order to determine the electrical force on the sphere along the cylinder radius (i.e., perpendicular to its axis) when either the radius of the sphere is small compared to that of the cylinder, or when the radius of the sphere is only slightly smaller than that of the cylinder. In both cases the force acts towards the centreline of the cylinder, and hence this force tends to stabilize electrophoresis of the sphere along the cylinder axis.

Astrocytic IP3 Rs: Contribution to Ca2+ signalling and hippocampal LTP.

Astrocytes regulate hippocampal synaptic plasticity by the Ca2+ dependent release of the N-methyl d-aspartate receptor (NMDAR) co-agonist d-serine. Previous evidence indicated that d-serine release would be regulated by the intracellular Ca2+ release channel IP3 receptor (IP3 R), however, genetic deletion of IP3 R2, the putative astrocytic IP3 R subtype, had no impact on synaptic plasticity or transmission. Although IP3 R2 is widely believed to be the only functional IP3 R in astrocytes, three IP3 R subtypes (1, 2, and 3) have been identified in vertebrates. Therefore, to better understand gliotransmission, we investigated the functionality of IP3 R and the contribution of the three IP3 R subtypes to Ca2+ signalling. As a proxy for gliotransmission, we found that long-term potentiation (LTP) was impaired by dialyzing astrocytes with the broad IP3 R blocker heparin, and rescued by exogenous d-serine, indicating that astrocytic IP3 Rs regulate d-serine release. To explore which IP3 R subtypes are functional in astrocytes, we used pharmacology and two-photon Ca2+ imaging of hippocampal slices from transgenic mice (IP3 R2-/- and IP3 R2-/- ;3-/- ). This approach revealed that underneath IP3 R2-mediated global Ca2+ events are an overlooked class of IP3 R-mediated local events, occurring in astroglial processes. Notably, multiple IP3 Rs were recruited by high frequency stimulation of the Schaffer collaterals, a classical LTP induction protocol. Together, these findings show the dependence of LTP and gliotransmission on Ca2+ release by astrocytic IP3 Rs. GLIA 2017;65:502-513.

Repulsion Between Finite Charged Plates with Strongly Overlapped Electric Double Layers.

Screened Coulomb interactions between uniformly charged flat plates are considered at very small plate separations for which the Debye layers are strongly overlapped, in the limit of small electrical potentials. If the plates are of infinite length, the disjoining pressure between the plates decays as an inverse power of the plate separation. If the plates are of finite length, we show that screening Debye layer charges close to the edge of the plates are no longer constrained to stay between the plates, but instead spill out into the surrounding electrolyte. The resulting change in the disjoining pressure is calculated analytically: the force between the plates is reduced by this edge correction when the charge density is uniform over the surface of the plates, and is increased when the surface is at constant potential. A similar change in disjoining pressure due to loss of lateral confinement of the Debye layer charges should occur whenever the sizes of the interacting charged objects become small enough to approach the Debye scale. We investigate the effect here in the context of a two-dimensional model problem that is sufficiently simple to yield analytical results.

Exploration of prescribing error reporting across primary care: a qualitative study.

OBJECTIVES: To explore barriers and facilitators to prescribing error reporting across primary care. DESIGN: Qualitative semi-structured face-to-face and telephone interviews were conducted to explore facilitators and barriers to reporting prescribing errors. Data collection and thematic analysis were informed by the COM-B model of behaviour change. Framework analysis was used for coding and charting the data with the assistance of NVivo software (V.12). General and context specific influences on prescribing error reporting were mapped to constructs from the COM-B model (ie, capability, opportunity and motivation). SETTING: Primary care organisations, including community pharmacy, general practice and community care from North East England. PARTICIPANTS: We interviewed a maximal variation purposive sample of 25 participants, including prescribers, community pharmacists and key stakeholders with primary care or medicines safety roles at local, regional and national levels. RESULTS: Our findings describe a range of factors that influence the capability, opportunity and motivation to report prescribing errors in primary care. Three key contextual factors are also highlighted that were found to underpin many of the behavioural influences on reporting in this setting: the nature of prescribing; heterogeneous priorities for error reporting across and within different primary care organisations; and the complex infrastructure of reporting and learning pathways across primary care. Findings suggest that there is a lack of consistency in how, when and by whom, prescribing errors are reported across primary care. CONCLUSIONS: Further research is needed to identify cross-organisational and interprofessional consensus on agreed reporting thresholds and how best to facilitate a more collaborative approach to reporting and learning, that is, sensitive to the needs and priorities of disparate organisations across primary care. Despite acknowledged challenges, there may be potential for an increased role of community pharmacy in prescribing error reporting to support future learning.

The 22q11.2 region regulates presynaptic gene-products linked to schizophrenia.

It is unclear how the 22q11.2 deletion predisposes to psychiatric disease. To study this, we generated induced pluripotent stem cells from deletion carriers and controls and utilized CRISPR/Cas9 to introduce the heterozygous deletion into a control cell line. Here, we show that upon differentiation into neural progenitor cells, the deletion acted in trans to alter the abundance of transcripts associated with risk for neurodevelopmental disorders including autism. In excitatory neurons, altered transcripts encoded presynaptic factors and were associated with genetic risk for schizophrenia, including common and rare variants. To understand how the deletion contributed to these changes, we defined the minimal protein-protein interaction network that best explains gene expression alterations. We found that many genes in 22q11.2 interact in presynaptic, proteasome, and JUN/FOS transcriptional pathways. Our findings suggest that the 22q11.2 deletion impacts genes that may converge with psychiatric risk loci to influence disease manifestation in each deletion carrier.

Pediatric lateral atlantodental interval: how much asymmetry is normal?

Imaging of the cervical spine is commonly performed in the pediatric patient population, typically after trauma, as well as for a variety of nontraumatic reasons. There are many challenges in the interpretation of these studies, particularly at the level of the atlantoaxial joint. We recognized a particular problem with assessing the lateral atlantodental interval in our emergency radiology department. Mild lateral atlantodental interval asymmetry in relatively asymptomatic patients was being interpreted as indicative of atlantoaxial rotatory fixation, which leads to the recommendation for dynamic computed tomographic examinations. The goal of this study was to define the reference range of the lateral atlantodental interval in pediatric patients to help avoid misinterpretation of radiographic findings and resultant excessive imaging.

Clinical Significance of Plasma CD9-Positive Exosomes in HIV Seronegative and Seropositive Lung Cancer Patients.

Recently, the role of exosomes in the progression of both cancer and HIV (human immunodeficiency virus) has been described. This study investigates the clinical significance of CD9-positive plasma exosomes in lung cancer patients, healthy individuals, and HIV-positive patients with or without lung cancer. Using a verified with transmission electron microscopy double-sandwich ELISA technique, plasma-derived exosomes were isolated and quantified from 210 lung cancer patients (including 44 metastatic patients with progressive disease after chemotherapy), 49 healthy controls, 20 patients with pulmonary granulomas, 19 HIV+ patients with lung cancer, 31 HIV+ patients without cancer, and 3 HIV+ patients with pulmonary granulomas. Plasma exosome concentrations differed between healthy controls, patients with immunocompetent pulmonary granulomas and patients with lung cancer even after chemotherapy (p < 0.001). Lung cancer patients after chemotherapy had lower exosome concentrations compared to patients with untreated lung cancer or granuloma (p < 0.001 for both). HIV+ patients without lung cancer had significantly higher exosome concentrations compared to HIV+ patients with lung cancer (p = 0.016). Although exosome concentrations differed between all different lung cancer histologies and healthy controls (p < 0.001 for all histologies), adjusted statistical significance was oµy retained for patients with granulomas and SCLC (Small-cell lung cancer, p < 0.001). HIV-induced immunodeficient patients with or without lung cancer had lower plasma exosomes compared to immunocompetent granuloma and lung cancer patients (p < 0.001). Finally, higher plasma exosomes were associated both on univariate (p = 0.044), and multivariate analysis (p = 0.040) with a better 3-year survival in stage II and III NSCLC (Non-small-cell lung carcinoma) patients. In conclusion, our study shows that CD9-positive plasma exosomes are associated with both lung cancer and HIV, prior chemotherapy, as well as with survival, suggesting a possible prognostic value.

Internet-based pharmacy and centralised dispensing: an exploratory mixed-methods study of the views of family practice staff.

OBJECTIVES: Over the last decade, technological advances, market competition and increasing pressures for efficiencies across healthcare systems have resulted in changes to the processes and policies involved in medicines prescribing and dispensing. The aim of this study was to explore the views of family practice staff, including GPs, on the perceived impact of changes associated with remote dispensing and the increasing availability of distance-selling pharmacies. METHODS: Exploratory mixed-methods study using qualitative focus groups and an online cross-sectional survey distributed to a non-probability sample of staff from family practices across England. Survey items were developed based on existing literature and initial thematic analysis from the focus groups and adapted using cognitive interviewing techniques. KEY FINDINGS: Findings suggest that family practice staff believe that where and how prescriptions are dispensed impacts on their practice and patients. Frequent contact with distance-selling pharmacies is not common; however, highlighted concerns included patient safety issues and the potential threat to the loss of valued elements and sustainability of community pharmacy and dispensing practices. Identified concerns and experiences are unlikely to be routinely discussed within or between practices, limiting opportunities for shared learning and consideration of the potential impact of changes to dispensing processes and policies. CONCLUSIONS: Further research is needed to confirm these exploratory findings, due to the low response rate and sample size. Findings, nevertheless, highlight how wider changes in dispensing processes may have unintended consequences on other aspects of the healthcare system.

Prescribing error reporting in primary care: a narrative synthesis systematic review.

Prescribing errors can cause avoidable harm to patients. Most prescriptions originate in primary care, where medications tend to be self-administered and errors have the most potential to cause harm. Reporting prescribing errors can identify trends and reduce the risk of the reoccurrence of incidents; however, under-reporting is common. The organisation of care and the movement of prescriptions from general practice to community pharmacy may create difficulties for professionals to effectively report errors. This review aims specifically to identify primary research studies that examine barriers and facilitators to prescription error reporting across primary care. A systematic research of the literature was completed in July 2019. Four databases (PubMed/Medline, Cochrane, CINAHL and Web of Science) were searched for relevant studies. No date or language limits were applied. Eligible studies were critically appraised using the Mixed Methods Appraisal Tool, and data were descriptively and narratively synthesised. Ten articles were included in the final analysis. Seven studies considered prescription errors and error reporting within general practice and three within a community pharmacy setting. Findings from the included studies are presented across five themes, including definition of an error, prescribing error reporting culture, reporting processes, communication and capacity. Healthcare professionals appreciate the value of prescription error reporting, but there are key barriers to implementation, including time, fear of reprisal and organisation separation within primary care.

Complete Genome Sequences of Cluster G Mycobacteriophage Darionha, Cluster A Mycobacteriophage Salz, and Cluster J Mycobacteriophage ThreeRngTarjay.

Mycobacteriophages Darionha, Salz, and ThreeRngTarjay are mycobacteriophages isolated using the host Mycobacterium smegmatis mc2155. Following isolation from soil samples, all three siphoviridae phages were characterized, and their genomes were sequenced and annotated.

ACET is a highly potent and specific kainate receptor antagonist: characterisation and effects on hippocampal mossy fibre function.

Kainate receptors (KARs) are involved in both NMDA receptor-independent long-term potentiation (LTP) and synaptic facilitation at mossy fibre synapses in the CA3 region of the hippocampus. However, the identity of the KAR subtypes involved remains controversial. Here we used a highly potent and selective GluK1 (formerly GluR5) antagonist (ACET) to elucidate roles of GluK1-containing KARs in these synaptic processes. We confirmed that ACET is an extremely potent GluK1 antagonist, with a Kb value of 1.4+/-0.2 nM. In contrast, ACET was ineffective at GluK2 (formerly GluR6) receptors at all concentrations tested (up to 100 microM) and had no effect at GluK3 (formerly GluR7) when tested at 1 microM. The X-ray crystal structure of ACET bound to the ligand binding core of GluK1 was similar to the UBP310-GluK1 complex. In the CA1 region of hippocampal slices, ACET was effective at blocking the depression of both fEPSPs and monosynaptically evoked GABAergic transmission induced by ATPA, a GluK1 selective agonist. In the CA3 region of the hippocampus, ACET blocked the induction of NMDA receptor-independent mossy fibre LTP. To directly investigate the role of pre-synaptic GluK1-containing KARs we combined patch-clamp electrophysiology and 2-photon microscopy to image Ca2+ dynamics in individual giant mossy fibre boutons. ACET consistently reduced short-term facilitation of pre-synaptic calcium transients induced by 5 action potentials evoked at 20-25Hz. Taken together our data provide further evidence for a physiological role of GluK1-containing KARs in synaptic facilitation and LTP induction at mossy fibre-CA3 synapses.

Solid-state nanopore hydrodynamics and transport.

The resistive pulse method based on measuring the ion current trace as a biomolecule passing through a nanopore has become an important tool in biotechnology for characterizing molecules. A detailed physical understanding of the translocation process is essential if one is to extract the relevant molecular properties from the current signal. In this Perspective, we review some recent progress in our understanding of hydrodynamic flow and transport through nanometer sized pores. We assume that the problems of interest can be addressed through the use of the continuum version of the equations of hydrodynamic and ion transport. Thus, our discussion is restricted to pores of diameter greater than about ten nanometers: such pores are usually synthetic. We address the fundamental nanopore hydrodynamics and ion transport mechanisms and review the wealth of observed phenomena due to these mechanisms. We also suggest future ionic circuits that can be synthesized from different ionic modules based on these phenomena and their applications.

Interleukin-1 Receptor 1 Deletion in Focal and Diffuse Experimental Traumatic Brain Injury in Mice.

Important differences in the biology of focal and diffuse traumatic brain injury (TBI) subtypes may result in unique pathophysiological responses to shared molecular mechanisms. Interleukin-1 (IL-1) signaling has been tested as a potential therapeutic target in preclinical models of cerebral contusion and diffuse TBI, and in a phase II clinical trial, but no published studies have examined IL-1 signaling in an impact/acceleration closed head injury (CHI) model. We hypothesized that genetic deletion of IL-1 receptor-1 (IL-1R1 KO) would be beneficial in focal (contusion) and CHI in mice. Wild type and IL-1R1 KO mice were subjected to controlled cortical impact (CCI), or to CHI. CCI produced brain leukocyte infiltration, HMGB1 translocation and release, edema, cell death, and cognitive deficits. CHI induced peak rotational acceleration of 9.7 × 105 ± 8.1 × 104 rad/s2, delayed time to righting reflex, and robust Morris water maze deficits without deficits in tests of anxiety, locomotion, sensorimotor function, or depression. CHI produced no discernable acute plasmalemma damage or cell death, blood-brain barrier permeability to IgG, or brain edema and only a modest increase in brain leukocyte infiltration at 72 h. In both models, mature (17 kDa) interleukin-1 beta (IL-1ß) was induced by 24 h in CD31+ endothelial cells isolated from injured brain but was not induced in CD11b+ cells in either model. High mobility group box protein-1 was released from injured brain cells in CCI but not CHI. Surprisingly, cognitive outcome in mice with global deletion of IL-1R1 was improved in CHI, but worse after CCI without affecting lesion size, edema, or infiltration of CD11b+/CD45+ leukocytes in CCI. IL-1R1 may induce unique biological responses, beneficial or detrimental to cognitive outcome, after TBI depending on the pathoanatomical subtype. Brain endothelium is a hitherto unrecognized source of mature IL-1ß in both models.

Repetitive head injury in adolescent mice: A role for vascular inflammation.

Repetitive mild traumatic brain injury during adolescence can induce neurological dysfunction through undefined mechanisms. Interleukin-1 (IL-1) contributes to experimental adult diffuse and contusion TBI models, and IL-1 antagonists have entered clinical trials for severe TBI in adults; however, no such data exist for adolescent TBI. We developed an adolescent mouse repetitive closed head injury (rCHI) model to test the role of IL-1 family members in post-injury neurological outcome. Compared to one CHI, three daily injuries (3HD) produced acute and chronic learning deficits and emergence of hyperactivity, without detectable gliosis, neurodegeneration, brain atrophy, and white matter loss at one year. Mature IL-1ß and IL-18 were induced in brain endothelium in 3HD but not 1HD, three hit weekly, or sham animals. IL-1ß processing was induced cell-autonomously in three-dimensional human endothelial cell cultures subjected to in vitro concussive trauma. Mice deficient in IL-1 receptor-1 or caspase-1 had improved post-injury Morris water maze performance. Repetitive mild CHI in adolescent mice may induce behavioral deficits in the absence of significant histopathology. The endothelium is a potential source of IL-1ß and IL-18 in rCHI, and IL-1 family members may be therapeutic targets to reduce or prevent neurological dysfunction after repetitive mild TBI in adolescents.

Combining NGN2 Programming with Developmental Patterning Generates Human Excitatory Neurons with NMDAR-Mediated Synaptic Transmission.

Transcription factor programming of pluripotent stem cells (PSCs) has emerged as an approach to generate human neurons for disease modeling. However, programming schemes produce a variety of cell types, and those neurons that are made often retain an immature phenotype, which limits their utility in modeling neuronal processes, including synaptic transmission. We report that combining NGN2 programming with SMAD and WNT inhibition generates human patterned induced neurons (hpiNs). Single-cell analyses showed that hpiN cultures contained cells along a developmental continuum, ranging from poorly differentiated neuronal progenitors to well-differentiated, excitatory glutamatergic neurons. The most differentiated neurons could be identified using a CAMK2A::GFP reporter gene and exhibited greater functionality, including NMDAR-mediated synaptic transmission. We conclude that utilizing single-cell and reporter gene approaches for selecting successfully programmed cells for study will greatly enhance the utility of hpiNs and other programmed neuronal populations in the modeling of nervous system disorders.

Complete Genome Sequences of Cluster A Mycobacteriophages BobSwaget, Fred313, KADY, Lokk, MyraDee, Stagni, and StepMih.

Seven mycobacteriophages from distinct geographical locations were isolated, using Mycobacterium smegmatis mc2155 as the host, and then purified and sequenced. All of the genomes are related to cluster A mycobacteriophages, BobSwaget and Lokk in subcluster A2; Fred313, KADY, Stagni, and StepMih in subcluster A3; and MyraDee in subcluster A18, the first phage to be assigned to that subcluster.

TC-2559 excites dopaminergic neurones in the ventral tegmental area by stimulating alpha4beta2-like nicotinic acetylcholine receptors in anaesthetised rats.

1. The in vivo effects of a selective partial agonist for neuronal nicotinic acetylcholine receptor (nAChRs) alpha4beta2 subtype, TC-2559, characterised recently in in vitro preparations, have been profiled. The brain bioavailability of TC-2559 and its effects on the spontaneous firing and bursting properties of the dopaminergic (DAergic) neurones recorded extracellularly in the ventral tegmental area (VTA) were studied following systemic administration in anaesthetised rats. 2. Cumulative doses of TC-2559 (0.021-1.36 mg kg(-1), i.v.) increased both the firing and bursting activities of VTA DA neurones. The effect of bolus doses of TC-2559 of 0.66 or 1.32 mg kg(-1), i.v., was approximately equivalent to that of 0.0665 mg kg(-1), i.v. nicotine. 3. The excitation evoked by both nicotine and TC-2559 was fully reversed by DHbetaE (0.39-0.77 mg kg(-1), i.v.), an alpha4beta2-subtype-preferring nicotinic antagonist, and application of nicotine after DHbetaE failed to evoke any excitation. MLA (0.23 mg kg(-1), i.v.), an alpha7 selective antagonist, failed to alter TC-2559-evoked excitation and bursting activities, and a novel alpha7 agonist (PSAB-OFP; 0.23 mg kg(-1), i.v.) was also without effect. 4. The present results indicated that TC-2559 fully mimics nicotine by increasing both the excitability and bursting behaviour of VTA DA neurones, effects that are predominantly due to activation of alpha4beta2-like nAChRs. 5. TC-2559 has been demonstrated to be a useful in vivo pharmacological tool for studying the alpha4beta2 subtype of nicotinic receptor.

The alpha4beta2 nicotinic acetylcholine receptor agonist TC-2559 impairs long-term potentiation in the dentate gyrus in vivo.

Nicotinic acetylcholine receptors (nAChR) are widely expressed throughout the nervous system, are involved in some fast excitatory neurotransmission, and play an important role in modulating the release of several neurotransmitters, including the major excitatory and inhibitory neurotransmitters, glutamate and GABA. We used a recently characterised alpha4beta2 nAChR subunit selective partial agonist, TC-2559, to study the effect of alpha4beta2 nAChR activation on synaptic plasticity in the medio-dorsal perforant pathway input to the dentate gyrus, in the intact nervous system in vivo. We show for the first time, that the selective activation of alpha4beta2 containing nAChR can reduce the level of long-term potentiation (LTP) induced by high frequency stimulation, an effect that was reversed by the selective antagonist, dihydro-beta-erythroidine (DbetaHE). This modulator role of nAChRs is in contrast to previous findings that used broad spectrum agonists, highlighting the complex actions of nicotine.