Publications by authors named "Robert D Dayton"

Wastewater surveillance has proven to be a useful tool for evidence-based epidemiology in the fight against the SARS-CoV-2 virus. It is particularly useful at the population level where acquisition of individual test samples may be time or cost-prohibitive. Wastewater surveillance for SARS-CoV-2 has typically been performed at wastewater treatment plants; however, this study was designed to sample on a local level to monitor the spread of the virus among three communities with distinct social vulnerability indices in Shreveport, Louisiana, located in a socially vulnerable region of the United States.

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Context: Diethylene glycol (DEG) is an organic compound found in household products but also as a counterfeit solvent in medicines. DEG poisonings are characterized by acute kidney injury (AKI) and by neurological sequelae such as decreased reflexes or face and limb weakness. Previous studies in male rats have demonstrated that neurotoxic effects develop only with the establishment of AKI, but the dose sensitivity of females to DEG toxicity is unknown.

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Context: Diethylene glycol (DEG) is an organic compound found in household products but also as an adulterant in medicines by acting as a counterfeit solvent. DEG poisonings have been characterized predominately by acute kidney injury (AKI), but also by delayed neurological sequelae such as decreased reflexes or face and limb weakness.

Objectives: Characterizing the neurological symptoms of DEG poisoning in a subacute animal model would create a clearer picture of overall toxicity and possibly make mechanistic connections between kidney injury and neuropathy.

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A risk factor for cardiovascular disease (CVD), mutant PCSK9, was expressed in APP/PS1 mice to study the CVD-Alzheimer's disease inter-relationship. Cholesterol levels were elevated by 5-6-fold from 3 to 13 weeks after PCSK9 gene transfer. We tested whether hypercholesterolemia would increase amyloid-β plaques at a relatively early stage of plaque deposition.

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Engineered recombinant adeno-associated virus (AAV) vectors have advanced the transduction of neurons in the CNS on an expansive, wide-scale basis since the papers first using AAV9 for this purpose. Wide-scale CNS expression is relevant to gene therapy as well as indispensable for basic studies such as disease modeling. For example, the wide-scale gene transfer approach could expedite hypothesis testing in vivo relative to the generation of germ-line transgenic mice for all of the genes of interest.

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Trace eyeblink conditioning is a hippocampus-dependent associative learning paradigm which is impaired in patients with Alzheimer's disease (AD) and animal AD models. Learning in this paradigm accompanies changes in oscillatory activity in forebrain regions, some of which are loci of pathogenic changes in prodromal AD stages. These observations motivated us to examine how cortical event-related potentials (ERPs) during this paradigm are affected by two features of the asymptomatic, AD-related brain abnormality, entorhinal tau accumulation and mild cholinergic deficit.

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Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are progressive neurodegenerative disorders marked in most cases by the nuclear exclusion and cytoplasmic deposition of the RNA binding protein TDP43. We previously demonstrated that ALS-associated mutant TDP43 accumulates within the cytoplasm, and that TDP43 mislocalization predicts neurodegeneration. Here, we sought to prevent neurodegeneration in ALS/FTD models using selective inhibitor of nuclear export (SINE) compounds that target exportin-1 (XPO1).

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Recombinant adeno-associated virus (AAV) vectors are a popular genetic approach in neuroscience because they confer such efficient transgene expression in the brain and spinal cord. A number of studies have used AAV to express pathological disease-related proteins in the dopaminergic neurons of the substantia nigra in situ ( e.g.

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Adeno-associated virus (AAV) vectors are a key reagent in the neurosciences for clustered regularly interspaced short palindromic repeats (CRISPR), optogenetics, cre-lox targeting, etc. The purpose of this manuscript is to aid the investigator attempting expansive central nervous system (CNS) gene transfer in the rat via tail vein injection of AAV. Wide-scale expression is relevant for conditions with widespread pathology, and a rat model is significant due to its greater size and physiologic similarities to humans compared to mice.

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A neural signature of asymptomatic preclinical Alzheimer's disease (AD) is disrupted connectivity between brain regions; however, its underlying mechanisms remain unknown. Here, we tested whether a preclinical pathologic feature, tau aggregation in the entorhinal cortex (EC) is sufficient to disrupt the coordination of local field potentials (LFPs) between its efferent regions. P301L-mutant human tau or green fluorescent protein (GFP) was virally overexpressed in the EC of adult rats.

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One of the proteins most frequently found in neuropathological lesions is the ubiquitin binding protein p62 (sequestosome 1). Post-mortem analysis of p62 is a defining diagnostic marker in several neurodegenerative diseases including amyotrophic lateral sclerosis and inclusion body myositis. Since p62 functions in protein degradation pathways including autophagy, the build-up of p62-positive inclusions suggests defects in protein clearance.

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Widespread genetic modification of cells in the central nervous system (CNS) with a viral vector has become possible and increasingly more efficient. We previously applied an AAV9 vector with the cytomegalovirus/chicken beta-actin (CBA) hybrid promoter and achieved wide-scale CNS transduction in neonatal and adult rats. However, this method transduces a variety of tissues in addition to the CNS.

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Background: Fused in sarcoma (FUS) is an RNA-binding protein associated with the neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration. ALS manifests in patients as a progressive paralysis which leads to respiratory dysfunction and failure, the primary cause of death in ALS. We expressed human FUS in rats to determine if FUS would induce ALS relevant respiratory changes to serve as an early stage disease indicator.

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AAV9 has emerged as an efficient adeno-associated virus (AAV) serotype for gene transfer to the central nervous system. We have used this technique to study aspects of amyotrophic lateral sclerosis (ALS) by administering AAV encoding the ALS-related gene transactive response DNA binding protein of 43 kDa (TDP-43) to neonatal rats. However, inducing the expression in adult subjects would be preferable to mimic the adult onset of symptoms in ALS.

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Background: Most amyotrophic lateral sclerosis (ALS) research has focused on mice, but there are distinct differences in the functional neuroanatomy of the corticospinal pathway in primates vs. rodents. A non-human primate model may be more sensitive and more predictive for therapeutic efficacy.

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Pathological inclusions containing transactive response DNA-binding protein 43 kDa (TDP-43) are common in several neurodegenerative diseases including amyotrophic lateral sclerosis (ALS). TDP-43 normally localizes predominantly to the nucleus, but during disease progression, it mislocalizes to the cytoplasm. We expressed TDP-43 in rats by an adeno-associated virus (AAV9) gene transfer method that transduces neurons throughout the central nervous system (CNS).

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Salivary glands are highly susceptible to radiation, and patients with head and neck cancer treated with radiotherapy invariably suffer from its distressing side effect, salivary hypofunction. The reduction in saliva disrupts oral functions, and significantly impairs oral health. Previously, we demonstrated that adenoviral-mediated expression of Tousled-like kinase 1B (TLK1B) in rat submandibular glands preserves salivary function after single-dose ionizing radiation.

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Introduction: Straightforward studies compared adeno-associated virus (AAV) serotypes to determine the most appropriate one for robust expression in the CNS. AAV9 was efficient when directly injected into the brain, but more surprisingly, AAV9 produced global expression in the brain and spinal cord after a peripheral, systemic route of administration to neonatal mice.

Areas Covered: Topics include AAV9 gene delivery from intraparenchymal, intravenous, intrathecal and intrauterine routes of administration, and related preclinical studies and disease models.

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Frontotemporal lobar degeneration (FTLD) is a neurodegenerative disease that involves cognitive decline and dementia. To model the hippocampal neurodegeneration and memory-related behavioral impairment that occurs in FTLD and other tau and TDP-43 proteinopathy diseases, we used an adeno-associated virus serotype 9 (AAV9) vector to induce bilateral expression of either microtubule-associated protein tau or transactive response DNA binding protein 43 kDa (TDP-43) in adult rat dorsal hippocampus. Human wild-type forms of tau or TDP-43 were expressed.

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Improved spread of transduction in the central nervous system (CNS) was achieved from intravenous administration of adeno-associated virus serotype-9 (AAV9) to neonatal rats. Spinal lower motor neuron transduction efficiency was estimated to be 78% using the highest vector dose tested at a 12-week interval. The widespread expression could aid studying diseases that affect both the spinal cord and brain, such as amyotrophic lateral sclerosis (ALS).

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Neurofibrillary tangles comprised of the microtubule-associated protein tau are pathological features of Alzheimer's disease and several other neurodegenerative diseases, such as progressive supranuclear palsy. We previously overexpressed tau in the substantia nigra of rats and mimicked some of the neurodegenerative sequelae that occur in humans such as tangle formation, loss of dopamine neurons, and microgliosis. To study molecular changes involved in the tau-induced disease state, we used DNA microarrays at an early stage of the disease process.

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Dopamine (DA) affects GABA neuronal function in the striatum and together these neurotransmitters play a large role in locomotor function. We recently reported that unilateral striatal administration of GDNF, a growth factor that has neurotrophic effects on DA neurons and enhances DA release, bilaterally increased striatal neuron activity related to locomotion in aged rats. We hypothesized that the GDNF enhancement of DA function and resulting bilateral enhancement of striatal neuronal activity was due to prolonged bilateral changes in DA- and GABA-regulating proteins.

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We attempted to monitor the nigrostriatal dopaminergic system in rats with positron emission tomography (PET) during the progression of two experimental disease states. One model was 6-hydroxydopamine (6-OHDA) lesioning and the other was direct gene transfer of the microtubule-associated protein tau to the substantia nigra using an adeno-associated virus vector (AAV9). The PET ligand was 6-[18F]fluoro-L-m-tyrosine (FMT), imaged prior to, and at two intervals after initiating dopaminergic neurodegeneration.

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