Publications by authors named "James A Cooper"

Clinical findings of hepatomegaly and splenomegaly, the abnormal enlargement of the liver and spleen, respectively, should prompt a broad differential diagnosis that includes metabolic, congestive, neoplastic, infectious, toxic, and inflammatory conditions. Among the metabolic diseases, lysosomal storage diseases (LSDs) are a group of rare and ultrarare conditions with a collective incidence of 1 in 5000 live births. LSDs are caused by genetic variants affecting the lysosomal enzymes, transporters, or integral membrane proteins.

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Lamotrigine, approved for use as an antiseizure medication as well as the treatment of bipolar disorder, inhibits sodium channels in the brain to reduce repetitive neuronal firing and pathological release of glutamate. The shared homology of sodium channels and lack of selectivity associated with channel blocking agents can cause slowing of cardiac conduction and increased proarrhythmic potential. The Vaughan-Williams classification system differentiates sodium channel blockers using biophysical properties of binding.

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The solid-state properties of organic radicals depend on radical-radical interactions that are influenced by the superstructure of the crystalline phase. Here, we report the synthesis and characterization of a substituted tetracationic cyclophane, cyclobis(paraquat--1,4-dimethoxyphenylene), which associates in its bisradical dicationic redox state with the methyl viologen radical cation () to give a 1:1 inclusion complex. The (super)structures of the reduced cyclophane and this 1:1 complex in the solid state deviate from the analogous (super)structures observed for the reduced state of cyclobis(paraquat--phenylene) and that of its trisradical tricationic complex.

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The mechanical properties of the actin cortex regulate shape changes during cell division, cell migration, and tissue morphogenesis. We show that modulation of myosin II (MII) filament composition allows tuning of surface tension at the cortex to maintain cell shape during cytokinesis. Our results reveal that MIIA generates cortex tension, while MIIB acts as a stabilizing motor and its inclusion in MII hetero-filaments reduces cortex tension.

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Defective anion transport is a hallmark of the genetic disease cystic fibrosis (CF). One approach to restore anion transport to CF cells utilises alternative pathways for transmembrane anion transport, including artificial anion carriers (anionophores). Here, we screened 22 anionophores for biological activity using fluorescence emission from the halide-sensitive yellow fluorescent protein.

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A class of γ-cyclodextrin-containing hybrid frameworks (CD-HFs) has been synthesized, employing γ-cyclodextrin (γ-CD) as the primary building blocks, along with 4-methoxysalicylate (4-MS) anions as the secondary building blocks. CD-HFs are constructed through the synergistic exploitation of coordinative, electrostatic, and dispersive forces. The syntheses have been carried out using an organic counteranion co-assembly strategy, which allows for the introduction of 4-MS, in place of inorganic OH, into the cationic γ-CD-containing metal-organic frameworks (CD-MOFs).

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Advances in fabrication have allowed tissue engineers to better mimic complex structures and tissue interfaces by designing nanofibrous scaffolds with spatially graded material properties. However, the nonuniform properties that grant the desired biomechanical function also make these constructs difficult to characterize. In light of this, we developed a novel procedure to create graded nanofibrous scaffolds and determine the spatial distribution of their material properties.

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Reported here is the synthesis, solid-state characterization, and redox properties of new triangular, threefold symmetric, viologen-containing macrocycles. Cyclotris(paraquat-p-phenylene) (CTPQT ) and cyclotris(paraquat-p-1,4-dimethoxyphenylene) (MCTPQT ) were prepared and their X-ray single-crystal (super)structures reveal intricate three-dimensional packing. MCTPQT results in nanometer-sized channels, in contrast with its parent counterpart CTPQT which crystallizes as a couple of polymorphs in the form of intercalated assemblies.

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Prompted by a knowledge of the photoprotective mechanism operating in photosystem supercomplexes and bacterial antenna complexes by pigment binding proteins, we have appealed to a boxlike synthetic receptor (·4Cl) that binds a photosensitizer, 5,15-diphenylporphyrin (), to provide photoprotection by regulating light energy. The hydrophilic renders soluble in water and modulates the phototoxicity of by trapping it in its cavity and releasing it when required. While trapping removes access to the triplet state, a pH-dependent release of diprotonated () restores the triplet deactivation pathway, thereby activating its ability to generate reactive oxygen species.

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Guest encapsulation is a fundamental property of coordination cages. However, there is a paucity of methods capable of quantifying the dynamics of guest binding processes. Here, we demonstrate nanopore detection of single-molecule binding within metallosupramolecular cages.

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Peptaibols are peptide antibiotics that typically feature an N-terminal acetyl cap, a C-terminal aminoalcohol, and a high proportion of α-aminoisobutyric acid (Aib) residues. To establish how each feature might affect the membrane-activity of peptaibols, biomimetic Aib foldamers with different lengths and terminal groups were synthesised. Vesicle assays showed that long foldamers (eleven Aib residues) with hydrophobic termini had the highest ionophoric activity.

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Supramolecular chirality may emerge from self-assembly processes to yield architectures that differ only in the topological arrangement of their constituent parts. Since the properties of the resulting enantiomeric assemblies are identical, purification and characterisation can be challenging. Here, we have examined the hypothesis that the intrinsic chirality of a protein nanopore can be exploited to detect supramolecular chirality.

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Background: Following reports of discoloration, including retinal pigmentation, in addition to known significant risks of urinary retention, central nervous system effects, and QTc prolongation, the retigabine indication was restricted to adjunctive treatment of partial onset seizures where other appropriate drug combinations have proved inadequate or have not been tolerated.

Objective: To ascertain the effectiveness of educational initiatives as reflected in physicians' understanding of retigabine-associated risks, management, and patient selection.

Methodology: An online, cross-sectional survey, designated a post-authorization safety study (24/9/2014-30/1/2015), recruited retigabine prescribers (RP) and retigabine non-prescribers (RNP) in seven countries, who had been sent a retigabine Dear Health Care Professional letter (June 2013).

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Electrospinning is a versatile fabrication technique that has been recently expanded to create nanofibrous structures that mimic ECM topography. Like many materials, electrospun constructs are typically characterized on a smaller scale, and scaled up for various applications. This established practice is based on the assumption that material properties, such as toughness, failure stress and strain, are intrinsic to the material, and thus will not be influenced by specimen geometry.

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Tyramine-substituted hyaluronic acid (HA-Tyr) hydrogels formed by the oxidative coupling reaction of hydrogen peroxide (HO) and horseradish peroxidase (HRP) have been used for cellular encapsulation and protein delivery. Crosslinking density and gelation time can be tuned by altering the HO and HRP concentrations. Previous studies using HA-Tyr constructs report significant mechanical degradation after 21 days of culture.

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Transmembrane anion transporters (anionophores) have potential for new modes of biological activity, including therapeutic applications. In particular they might replace the activity of defective anion channels in conditions such as cystic fibrosis. However, data on the biological effects of anionophores are scarce, and it remains uncertain whether such molecules are fundamentally toxic.

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Purpose: Long-term levodopa therapy and related fluctuating plasma concentrations are associated with between-dose periods of 'off time' resulting in substantial variation in symptoms and functioning throughout the day in people with Parkinson's (PwP).

Methods: PwP across UK, France, Spain and Italy completed an online survey to explore: the impact of 'off time' on (1) health-related quality of life (HRQL) and (2) on functioning and ability to undertake usual activities; (3) the value of 'off time' relative to other factors associated with Parkinson's through a stated preference discrete choice experiment (SPDCE).

Results: In total, 305 PwP completed the online survey.

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Transmembrane anion carriers (anionophores) have potential for biological activity, including the treatment of channelopathies such as cystic fibrosis. A new family of anionophores has been synthesized, in which three thiourea groups are mounted on a cyclohexane-based scaffold. Though conceptually related to earlier polycyclic systems, these molecules are simpler and far more accessible.

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Unlike selective serotonin reuptake inhibitors (SSRIs), bupropion may be classified as a dual noradrenaline and dopamine reuptake inhibitor, a difference with potential implications for the treatment of residual sleepiness and fatigue in major depressive disorder (MDD). Post-hoc analysis of subjects with remitted MDD was performed on data pooled from six double-blind, randomized trials comparing the European Union (EU)-approved dose of ≤300 mg/day bupropion with SSRIs (sertraline, paroxetine or escitalopram) for the resolution of sleepiness and fatigue. Hypersomnia score was defined as the sum of scores of the Hamilton Depression Rating Scale (HDRS) items 22, 23, and 24; fatigue score as HDRS item 13 score; and remission as HDRS-17≤7.

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Hybrid scaffolds for cartilage tissue engineering provide the potential for high stiffness properties in tension and compression while exhibiting the viscoelastic response found in hydrogels and native cartilage tissue. We investigate the impact of a hybrid scaffold fabricated from a hyaluronic acid (HA)-based hydrogel combined with porous poly(ε-caprolactone) (PCL) material formed by a particulate leaching method to study dedifferentiated chondrocyte response. The material properties of the hybrid scaffold showed mean Young's moduli in tension which were similar to human articular cartilage but not statistically different between the hybrid and porous PCL scaffolds at 2.

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PLLA fibrous tissue scaffolds with controlled fiber nanoscale surface roughness are fabricated with a novel centrifugal jet spinning process. The centrifugal jet spinning technique is a highly efficient synthesis method for micron- to nano-sized fibers with a production rate up to 0.5 g min(-1).

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Next-day residual effects of single evening doses of 3 mg of eszopiclone, 7.5 mg of zopiclone, and placebo were assessed in a randomized, double-blind, placebo-controlled, 3-way crossover study that used a mild sleep restriction protocol (sleep duration, 7 hours). During each period, 91 healthy volunteers spent 2 consecutive nights in the laboratory with time in bed restricted to 7 hours.

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Objective: Long-standing evidence indicates that Alzheimer's disease patients with behavioral symptoms have a worse prognosis and a more rapid disease progression. The current retrospective analysis evaluated the efficacy and safety of memantine in a subpopulation of patients with Alzheimer's disease exhibiting behavioral symptoms of agitation/aggression or psychosis at baseline.

Method: A pooled analysis was conducted in people with agitation/aggression or psychosis from 3 large 6-month, randomized studies in moderately severe to severe Alzheimer's disease.

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A systematic investigation of tissue engineering scaffolds prepared by salt leaching of a photopolymerized dimethacrylate was performed to determine how the scaffold structure (porosity, pore size, etc.) can be controlled and also to determine how the scaffold structure and the mechanical properties are related. Two series of scaffolds were prepared with (1) the same polymer-to-salt ratio but different salt sizes (ranging from average size of 100 to 390 microm) and (2) the same salt size but different polymer-to-salt ratios (ranging from salt mass of 70 to 90%).

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There are >200,000 anterior cruciate ligament (ACL) ruptures each year in the United States, and, due to the poor healing properties of the ACL, surgical reconstruction with autograft or allograft tissue is the current treatment of these injuries. To regenerate the ACL, the ideal matrix should be biodegradable, porous, and exhibit sufficient mechanical strength to allow formation of neoligament tissue. Researchers have developed ACL scaffolds with collagen fibers, silk, biodegradable polymers, and composites with limited success.

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