Publications by authors named "Andrew N Clarkson"

Article Synopsis
  • Hypertension is a significant risk factor for both stroke and cognitive decline, but its specific impact on cognitive impairment after a stroke is still uncertain.
  • In a study with C57BL/6J mice, researchers induced hypertension and then conducted strokes to assess cognitive outcomes using the Barnes maze and analyzed the brain's transcriptomic profile through RNA sequencing.
  • Results indicated that hypertensive mice experienced worse cognitive performance and more brain injury compared to normotensive mice after a stroke, with over 1500 genes linked to neuroinflammation being differentially expressed.
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Adolescent idiopathic scoliosis (AIS) is the most common form of scoliosis, in which spinal curvature develops in adolescence, and 90% of patients are female. Scoliosis is a debilitating disease that often requires bracing or surgery in severe cases. AIS affects 2%-5.

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  • The global rise in aging populations is linked to a higher incidence of Alzheimer's disease (AD) and its socioeconomic impacts, driven largely by abnormal amyloid-β (Aβ) metabolism.
  • Current treatments focusing on Aβ removal have shown limited cognitive benefits, highlighting the complexity of AD's causes, which include a range of factors like tau accumulation, neuroinflammation, and vascular dysfunction.
  • To effectively treat AD, extensive research is needed on neurodegeneration mechanisms, identifying intervention targets, and developing combinatorial treatment strategies, with the overarching goal of reversing cognitive decline through the Alzheimer's Disease Neuroprotection Research Initiative.
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Control comparator selection is a critical trial design issue. Preclinical and clinical investigators who are doing trials of stroke recovery and rehabilitation interventions must carefully consider the appropriateness and relevance of their chosen control comparator as the benefit of an experimental intervention is established relative to a comparator. Establishing a strong rationale for a selected comparator improves the integrity of the trial and validity of its findings.

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Control comparator selection is a critical trial design issue. Preclinical and clinical investigators who are doing trials of stroke recovery and rehabilitation interventions must carefully consider the appropriateness and relevance of their chosen control comparator as the benefit of an experimental intervention is established relative to a comparator. Establishing a strong rationale for a selected comparator improves the integrity of the trial and validity of its findings.

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Excitotoxicity, a neuronal death process in neurological disorders such as stroke, is initiated by the overstimulation of ionotropic glutamate receptors. Although dysregulation of proteolytic signaling networks is critical for excitotoxicity, the identity of affected proteins and mechanisms by which they induce neuronal cell death remain unclear. To address this, we used quantitative N-terminomics to identify proteins modified by proteolysis in neurons undergoing excitotoxic cell death.

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Ca/calmodulin-dependent protein kinase II alpha (CaMKIIα) is a major contributor to physiological and pathological glutamate-mediated Ca signals, and its involvement in various critical cellular pathways demands specific pharmacological strategies. We recently presented γ-hydroxybutyrate (GHB) ligands as the first small molecules selectively targeting and stabilizing the CaMKIIα hub domain. Here, we report that the cyclic GHB analogue 3-hydroxycyclopent-1-enecarboxylic acid (HOCPCA), improves sensorimotor function after experimental stroke in mice when administered at a clinically relevant time and in combination with alteplase.

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Regeneration of neural tissue and recovery of lost functions following an accident or disease to the central nervous system remains a major challenge worldwide, with limited treatment options available. The main reason for the failure of conventional therapeutic techniques to regenerate neural tissue is the presence of blood-brain barrier separating nervous system from systemic circulation and the limited capacity of self-regeneration of the nervous system. Injectable hydrogels have shown great promise for neural tissue engineering given their suitability for minimally invasive in situ delivery and tunable mechanical and biological properties.

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Stroke remains a leading cause of adult disability with treatments limited to thrombolytic therapies that are severely limited by a narrow therapeutic window. The potential of hundreds of other therapeutic agents cannot be evaluated due to their poor ability to cross the blood-brain barrier. Recently, biopolymer hydrogels have shown promise at overcoming these obstacles via the delivering of therapeutic molecules (pharmacological, mRNA, stem cells, etc.

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Article Synopsis
  • Analyzing cognitive performance is crucial for assessing deficits in individuals who have suffered strokes or central nervous system injuries, and touchscreen testing has gained popularity for its reproducibility and reduced stress on animal subjects.
  • The chapter explains how to set up and conduct four specific touchscreen tasks with adult mice to evaluate various cognitive abilities, including memory and cognitive flexibility.
  • Additionally, it offers practical tips for researchers and highlights important considerations when using these touchscreen tests in CNS injury models to enhance understanding of brain function and improve treatment strategies.
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In this review, we summarize recent work on the "green synthesis" of carbon nanoparticles (CNPs) and their application with a focus on biomedical applications. Recent developments in the green synthesis of carbon nanoparticles, from renewable precursors and their application for environmental, energy-storage and medicinal applications are discussed. CNPs, especially carbon nanotubes (CNTs), carbon quantum dots (CQDs) and graphene, have demonstrated utility as high-density energy storage media, environmental remediation materials and in biomedical applications.

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Ischemic stroke is a leading cause of death and disability worldwide. Methods to alleviate functional deficits after ischemic stroke focus on restoration of cerebral blood flow to the affected area. However, pharmacological or surgical methods such as thrombolysis and thrombectomy have a narrow effective window.

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Ca/calmodulin-dependent protein kinase II (CaMKII) is a major mediator of Ca-dependent signaling pathways in various cell types throughout the body. Its neuronal isoform CaMKIIα () centrally integrates physiological but also pathological glutamate signals directly downstream of glutamate receptors and has thus emerged as a target for ischemic stroke. Previous studies provided evidence for the involvement of CaMKII activity in ischemic cell death by showing that CaMKII inhibition affords substantial neuroprotection.

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Stroke therapy has largely focused on preventing damage and encouraging repair outside the ischemic core, as the core is considered irreparable. Recently, several studies have suggested endogenous responses within the core are important for limiting the spread of damage and enhancing recovery, but the role of blood flow and capillary pericytes in this process is unknown. Using the Rose Bengal photothrombotic model of stroke, we illustrate blood vessels are present in the ischemic core and peri-lesional regions 2 weeks post stroke in male mice.

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Ca/calmodulin-dependent protein kinase II alpha (CaMKIIα) is a potential target for acute neuroprotection due to its key role in physiological and pathological glutamate signaling. The hub domain organizes the CaMKII holoenzyme into large oligomers, and additional functional effects on holoenzyme activation have lately emerged. We recently reported that compounds related to the proposed neuromodulator γ-hydroxybutyrate (GHB) selectively bind to the CaMKIIα hub domain and increase hub thermal stabilization, which is believed to have functional consequences and to mediate neuroprotection.

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Stroke-induced cognitive impairments remain of significant concern, with very few treatment options available. The involvement of glycosaminoglycans in neuroregenerative processes is becoming better understood and recent advancements in technology have allowed for cost-effective synthesis of novel glycomimetics. The current study evaluated the therapeutic potential of two novel glycomimetics, compound A and G, when administered systemically five-days post-photothrombotic stroke to the PFC.

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Introduction: Neutrophil accumulation is a well-established feature of Alzheimer's disease (AD) and has been linked to cognitive impairment by modulating disease-relevant neuroinflammatory and vascular pathways. Neutrophils express high levels of the oxidant-generating enzyme myeloperoxidase (MPO), however there has been controversy regarding the cellular source and localisation of MPO in the AD brain.

Materials And Methods: We used immunostaining and immunoassays to quantify the accumulation of neutrophils in human AD tissue microarrays and in the brains of APP/PS1 mice.

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Article Synopsis
  • Spontaneous recovery of motor and cognitive functions after a stroke varies among individuals and may be linked to neurotransmitter systems and brain regions that promote adaptability and learning.
  • A study with 42 stroke patients assessed cognitive function both shortly after the stroke and one year later, using advanced MRI techniques and neuropsychological tests to track changes in memory types.
  • Findings revealed that structural brain features, particularly those related to the cholinergic basal forebrain, are significant predictors for improvements in long-term memory performance and suggest common neural infrastructures for cognitive recovery across different memory domains.
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N-acylethanolamines (NAE, also called ethanolamides) are significant lipid signaling molecules with anti-inflammatory, pain-relieving, cell-protective, and anticancer properties. Here, we present the use of a hitherto unreported group of Δ3-NAE and also some Δ4- and Δ5-NAE, in in vitro and in vivo assays to gain a better understanding of their structure-bioactivity relationships. We have developed an efficient synthetic method to rapidly produce novel unlabeled and C-labeled Δ3-NAE (NAE-18:5n-3, NAE-18:4n-6) and Δ4-NAE (NAE-22:5n-6).

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Obesity is a major risk factor for developing cancer, with obesity-induced immune changes and inflammation in breast (BC) and colorectal cancer (CRC) providing a potential link between the two. This study investigates systemic effects of obesity on adaptive and innate immune cells in healthy and tumour-bearing mice. Immune cells from lean and obese mice were phenotyped prior to implantation of either BC (C57mg and EO771.

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Ca/calmodulin-dependent protein kinase II alpha subunit (CaMKIIα) is a key neuronal signaling protein and an emerging drug target. The central hub domain regulates the activity of CaMKIIα by organizing the holoenzyme complex into functional oligomers, yet pharmacological modulation of the hub domain has never been demonstrated. Here, using a combination of photoaffinity labeling and chemical proteomics, we show that compounds related to the natural substance γ-hydroxybutyrate (GHB) bind selectively to CaMKIIα.

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Humans require a plethora of higher cognitive skills to perform executive functions, such as reasoning, planning, language and social interactions, which are regulated predominantly by the prefrontal cortex. The prefrontal cortex comprises the lateral, medial and orbitofrontal regions. In higher primates, the lateral prefrontal cortex is further separated into the respective dorsal and ventral subregions.

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Article Synopsis
  • Neuronal survival and reconnection after a stroke are essential for recovery, influenced by the balance of excitation and inhibition in the brain.
  • In the early phase of stroke, enhancing inhibition through GABA receptor modulation can help, whereas in later stages, the opposite modulation can support recovery.
  • The study hypothesizes that octadecaneuropeptide (ODN), an astrocyte-derived modulator, can initially hinder recovery in acute stroke but, when used after three days, promotes motor recovery by correcting cortical excitability.
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Ischemic stroke remains a leading cause of disability worldwide, with limited treatment options available. This study investigates GABA receptors as novel pharmacological targets for stroke recovery. The expression of 1 and 2 mRNA in mice were determined in peri-infarct tissue following photothrombotic motor cortex stroke.

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Stroke-induced cognitive impairments are of significant concern, however mechanisms that underpin these impairments remain poorly understood and researched. To further characterise cognitive impairments in our frontal cortex stroke model, and to align our assessments with what is used clinically, we tested young C57BL/6J mice trained in operant touchscreen chambers to complete the trial-unique nonmatched-to-location (TUNL) task. Based on baseline performance, animals were given either stroke (n = 12) or sham (n = 12) surgery using a photothrombosis model, bilaterally targeting the frontal cortex.

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