Publications by authors named "Arthur A Simen"

Article Synopsis
  • Fall risk and cognitive impairment are common issues in Parkinson's disease, necessitating effective treatments.
  • The study evaluated the safety and efficacy of TAK-071, a targeted medication, in individuals with Parkinson's who also experience these challenges.
  • Despite not showing significant improvement in gait variability, TAK-071 was found to enhance cognitive function, marking a potential positive outcome for patients.
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Introduction: The understanding of the pathological events in Alzheimer's disease (AD) has advanced dramatically, but the successful translation from rodent models into efficient human therapies is still problematic.

Methods: To examine how tau pathology can develop in the primate brain, we injected 12 macaques with a dual tau mutation (P301L/S320F) into the entorhinal cortex (ERC). An investigation was performed using high-resolution microscopy, magnetic resonance imaging (MRI), positron emission tomography (PET), and fluid biomarkers to determine the temporal progression of the pathology 3 and 6 months after the injection.

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Aims: TAK-071 is a muscarinic M receptor positive allosteric modulator designed to have low cooperativity with acetylcholine. This was a first-in-human study to evaluate the safety, pharmacokinetics, and pharmacodynamics of TAK-071.

Methods: TAK-071 was administered as single and multiple doses in a randomized, double-blind, placebo-controlled, parallel-group design in healthy volunteers alone and in combination with donepezil.

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: The assessment of patients with generalized anxiety disorder (GAD) to deteremine whether a medication intervention is necessary is not always clear and might benefit from a second opinion. However, second opinions are time consuming, expensive, and not practical in most settings. We obtained independent, second opinion reviews of the primary clinician's assessment via audio-digital recording.

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  • Early life neglect can lead to increased risks of developing mental health issues like depression and anxiety later in life.
  • Recent research found specific epigenetic changes in genes (ID3, GRIN1, TPPP) linked to depression in maltreated children.
  • Further analysis in a mouse model of maternal neglect showed these genes were significant predictors of anxiety and depression behaviors, supporting their role in mental health issues stemming from early stress.
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Objectives: We sought to validate Cognitive Research Corporation's Driving Simulator (CRCDS Mini-Sim) for studies of drug safety with respect to driving ability.

Methods: A total of 30 healthy subjects were randomized to receive placebo or 7.5 mg zopiclone, a hypnotic known to impair driving, in random order during the 2 treatment periods of a 2 period crossover design.

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Non-nucleoside reverse transcriptase inhibitors are important antiretroviral agents for the treatment of human immunodeficiency virus. Some non-nucleoside reverse transcriptase inhibitors, in particular efavirenz, have prominent effects on sleep, cognition and psychiatric variables that limit their tolerability. To avoid confounds due to drug-drug and drug-disease interactions, we assessed the effects of efavirenz in healthy volunteers on sleep, cognition and psychological endpoints during the first week of treatment.

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The pattern of neurodegeneration in Alzheimer's disease (AD) is very distinctive: neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau selectively affect pyramidal neurons of the aging association cortex that interconnect extensively through glutamate synapses on dendritic spines. In contrast, primary sensory cortices have few NFTs, even in late-stage disease. Understanding this selective vulnerability, and why advancing age is such a high risk factor for the degenerative process, may help to reveal disease etiology and provide targets for intervention.

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Background: Disrupted in schizophrenia 1 (DISC1) is a protein implicated in schizophrenia, bipolar disorder, major depressive disorder, and autism. To date, most of research examining DISC1 function has focused on its role in neurodevelopment, despite its presence throughout life. DISC1 also regulates cyclic adenosine monophosphate (cAMP) signaling by increasing type 4 phosphodiesterase catabolism of cAMP when cAMP concentrations are high.

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  • Child neglect is the most common type of maltreatment in the U.S., leading to serious public health issues and long-term mental health problems in affected children, such as PTSD and depression.
  • Research has primarily focused on stress response systems to understand these issues, and the study uses a mouse model to investigate the molecular impacts of early-life neglect through various advanced techniques.
  • The findings suggest new insights into behavioral deficits similar to those seen in neglected children, with an emphasis on novel biological pathways like protein translation and myelination.
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The μ-opioid receptor mediates rewarding effects of alcohol and illicit drugs. We hypothesized that altered DNA methylation in the μ-opioid receptor gene (OPRM1) might influence the vulnerability to alcohol dependence (AD). Genomic DNA was extracted from the peripheral blood of 125 European Americans with AD and 69 screened European American controls.

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  • HCN channels, linked to psychosis risk, are encoded by four genes (HCN1-4) and activated by cyclic AMP (cAMP).
  • A study aimed to determine if genetic variations in these genes are associated with depression or cognitive impairment in a Scottish population.
  • The findings showed no significant links between the genetic variations in HCN channels and the risks of depression, neuroticism, or cognitive performance.
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Major depressive disorder (MDD) has been linked to changes in function and activity of the hippocampus, one of the central limbic regions involved in regulation of emotions and mood. The exact cellular and molecular mechanisms underlying hippocampal plasticity in response to stress are yet to be fully characterized. In this study, we examined the genetic profile of micro-dissected subfields of post-mortem hippocampus from subjects diagnosed with MDD and comparison subjects matched for sex, race and age.

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Background: Systematic processing noise, which includes batch effects, is very common in microarray experiments but is often ignored despite its potential to confound or compromise experimental results. Compromised results are most likely when re-analysing or integrating datasets from public repositories due to the different conditions under which each dataset is generated. To better understand the relative noise-contributions of various factors in experimental-design, we assessed several Illumina and Affymetrix datasets for technical variation between replicate hybridisations of Universal Human Reference (UHRR) and individual or pooled breast-tumour RNA.

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Background: Due to the cross-sectional design of most existing studies, longitudinal characterization of treatment for depression in older persons is largely unknown.

Method: Seven hundred fifty-four men and women (aged 70+ years) underwent monthly assessments of mental health professional use and 18-month assessments of antidepressant medication use and depressive symptoms over 9 years. Scores of ≥20 on the Center for Epidemiological Studies-Depression (CES-D) scale denoted depression.

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Using a novel mouse model of early life neglect and abuse (ENA) based on maternal separation with early weaning, George et al. (BMC Neurosci 11:123, 2010) demonstrated behavioral abnormalities in adult mice, and Bordner et al. (Front Psychiatry 2(18):1-18, 2011) described concomitant changes in mRNA and protein expression.

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Early life neglect is an important public health problem which can lead to lasting psychological dysfunction. Good animal models are necessary to understand the mechanisms responsible for the behavioral and anatomical pathology that results. We recently described a novel model of early life neglect, maternal separation with early weaning (MSEW), that produces behavioral changes in the mouse that persist into adulthood.

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Hyperpolarization activated cyclic nucleotide-gated (HCN) potassium channels are implicated in the control of neuronal excitability and are expressed widely in the brain. HCN4 is expressed in brain regions relevant to mood and anxiety disorders including specific thalamic nuclei, the basolateral amygdala, and the midbrain dopamine system. We therefore examined the association of HCN4 with a group of mood and anxiety disorders.

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As the average lifespan continues to climb because of advances in medical care, there is a greater need to understand the factors that contribute to quality of life in the elderly. The capacity to live independently is highly significant in this regard, but is compromised by cognitive dysfunction. Aging is associated with decreases in cognitive function, including impairments in episodic memory and executive functioning.

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Article Synopsis
  • Aging in humans leads to changes in cognition, motivation, and motor performance, which researchers hypothesized also occur in aging mice due to similar brain mechanisms, particularly in the medial prefrontal cortex.
  • In a study, scientists evaluated behavioral and cognitive performance in mice at different ages (6, 18, and 24 months) and analyzed tissue and serum for immune responses.
  • Results indicated that age-related declines in cognitive, motivational, and motor functions in mice are linked to changes in immune gene expression in the brain, particularly involving microglial cells.*
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The lifetime prevalence (∼16%) and the economic burden ($100 billion annually) associated with major depressive disorder (MDD) make it one of the most common and debilitating neurobiological illnesses. To date, the exact cellular and molecular mechanisms underlying the pathophysiology of MDD have not been identified. Here we use whole-genome expression profiling of postmortem tissue and show significantly increased expression of mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP-1, encoded by DUSP1, but hereafter called MKP-1) in the hippocampal subfields of subjects with MDD compared to matched controls.

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Article Synopsis
  • Childhood adversity is linked to an increased risk of mood, anxiety, impulse control, and substance disorders, but the biological mechanisms behind this are not well understood.
  • Researchers developed a new mouse model called Maternal Separation with Early Weaning (MSEW) to study the lasting effects of early life neglect, which showed significant behavioral changes in C57BL/6 and DBA/2 mice.
  • The findings suggest that MSEW can be a valuable tool for understanding behavioral issues linked to early life neglect, potentially leading to new treatment strategies.
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The delta-opioid receptor mediates rewarding effects of many substances of abuse. We reported an increased frequency of the minor G-allele of single-nucleotide polymorphism (SNP) rs569356 (the only variant identified so far in the promoter region of the delta-opioid receptor gene (OPRD1)) in subjects with opioid dependence. In this study, we examined the functional significance of this variant.

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Cannabis has been reported as a likely risk factor for the development of psychosis, and a gene × environment interaction with the catechol-O-methyltransferase (COMT) gene has been proposed. Moreover, COMT has been separately linked to affective symptoms in psychosis. Despite a high rate of cannabis abuse and affective symptoms in African Americans, no studies exploring a relationship between COMT and psychosis in this group have been reported.

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Schizophrenia is a disorder of the association cortices, with especially prominent structural and functional deficiencies in the dorsolateral prefrontal cortex (PFC). True dorsolateral PFC is found only in higher primates, and is characterized by highly elaborate pyramidal cells with extensive recurrent connections. The development of the primate PFC also involves distinct developmental and genetic pathways.

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