Publications by authors named "Donald R Johns"

Our objective was to determine whether serum urate predicts ALS progression. A study population comprised adult participants of EMPOWER (n = 942), a phase III clinical trial to evaluate the efficacy of dexpramipexole to treat ALS. Urate was measured in blood samples collected during enrollment as part of the routine block chemistry.

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Objective: To study the attributes of quantitative strength testing using hand-held dynamometry (HHD) as an efficacy measure in 2 large phase 3 amyotrophic lateral sclerosis (ALS) trials.

Methods: In the phase 3 trials of ceftriaxone and dexpramipexole, 513 and 943 patients, respectively, were enrolled in double-blind, randomized, placebo-controlled trials with planned follow-up of at least 1 year. Patients were studied every 3 months in the ceftriaxone study and every 2 months in the dexpramipexole study.

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Introduction: AQW051, an α7-nicotinic acetylcholine receptor partial agonist, enhanced cognitive function in rodent models of learning and memory. This study evaluated brain activation during performance of a working memory task (WMT) and an episodic memory task (EMT), and the effect of AQW051 on task-related brain activation and performance in subjects with schizophrenia.

Methods: This was a double-blind, randomized, placebo-controlled, multicenter, 2-period cross-over trial (NCT00825539) in participants with chronic, stable schizophrenia.

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The objective of this study was to assess the effect of secukinumab, a monoclonal antibody that inhibits interleukin (IL)-17A, on number of new active brain magnetic resonance imaging (MRI) lesions in subjects with relapsing-remitting multiple sclerosis (MS). Subjects (N = 73) were randomized 1:1 to secukinumab 10 mg/kg or placebo by intravenous infusion at weeks 0, 2, 4, 8, 12, 16, and 20. MRI scans were obtained within 30 days prior to randomization, on a monthly basis during the treatment period, and at study completion.

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Metabotropic glutamate receptors type 5 (mGluR5) are implicated in regulation of synaptic plasticity and learning, and were the focus of our investigation in human Parkinson's disease (PD) patients with dyskinesias and wearing-off, and in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) monkeys with dyskinesias. Using the selective mGluR5 ligand [(3)H]ABP688 autoradiography, we measured mGluR5 in brain slices from 11 normal and 14 PD patients and from MPTP monkeys, in relation to motor complications (dyskinesias and wearing-off) associated with treatment with l-dopa. In 16 monkeys with a bilateral MPTP lesion and four controls, [(3)H]ABP688 specific binding was elevated in the striatum of dyskinetic l-dopa-treated MPTP monkeys but not in MPTP monkeys without dyskinesias compared to controls.

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Somatic mitochondrial DNA (mtDNA) point mutations reach high levels in the brain. However, the cell types that accumulate mutations and the patterns of mutations within individual cells are not known. We have quantified somatic mtDNA mutations in 28 single neurons and in 18 single glia from post-mortem human substantia nigra of six control subjects.

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Dramatic advances in our understanding of the molecular genetic basis of Leber's hereditary optic neuropathy (LHON) have revolutionized our ability to diagnose and prognosticate this disease. Unfortunately no corresponding advances in the treatment of LHON have emerged. Glaucoma is a prevalent form of optic neuropathy that has been studied extensively.

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Mitochondrial cytopathies are associated with increased free radical generation and paracrystalline inclusions. Paracrystalline inclusions were serendipitously found in a young male athlete with a very high respiratory exchange ratio during steady-state exercise; he also had an unusually low aerobic capacity. Direct sequencing of the mitochondrial DNA (mtDNA) coding regions revealed a novel missense mutation (G15497A) resulting in a glycine-->serine conversion at a highly conserved site in the cytochrome b gene in the subject, his mother, and sister.

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Oxidative damage to mitochondrial DNA (mtDNA) increases with age in the brain and can induce G:C to T:A and T:A to G:C point mutations. Though rare at any particular site, multiple somatic mtDNA mutations induced by oxidative damage or by other mechanisms may accumulate with age in the brain and thus could play a role in aging and neurodegenerative diseases. However, no prior study has quantified the total burden of mtDNA point mutation subtypes in the brain.

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Mitochondrial DNA (mtDNA) mutations can cause rare forms of dystonia, but the role of mtDNA mutations in other types of dystonia is not well understood. We now report identification by sequencing, restriction endonuclease analyses, and clonal analyses of a heteroplasmic missense A to G base pair substitution at nucleotide position 3796 (A3796G) in the gene encoding the ND1 subunit of mitochondrial complex I in a patient with adult-onset dystonia, spasticity, and core-type myopathy. The mutation converts a highly conserved threonine to an alanine.

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