Publications by authors named "S M Eggan"

The global pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has highlighted the disparity between developed and developing countries for infectious disease surveillance and the sequencing of pathogen genomes. The majority of SARS-CoV-2 sequences published are from Europe, North America, and Asia. Between April 2020 and January 2022, 795 SARS-CoV-2-positive nares swabs from individuals in the U.

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The deleterious effects of cannabis use in schizophrenia have been linked, in part, to underlying disturbances in endogenous cannabinoid signaling in the prefrontal cortex. However, while receptor autoradiography studies of the primary cannabinoid receptor (CB1R) have consistently found higher CB1R binding in the prefrontal cortex in schizophrenia, deficits in CB1R mRNA levels and protein immunoreactivity have also been reported in the illness. To investigate this apparent discrepancy, we quantified CB1R binding using receptor autoradiography with the selective CB1R ligand [(3)H]-OMAR in the prefrontal cortex of 21 subjects with schizophrenia who were previously found to have lower levels of both CB1R mRNA using in situ hybridization and CB1R protein using radioimmunocytochemistry relative to matched healthy comparison subjects.

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Markers of GABA neurotransmission are altered in multiple regions of the neocortex in individuals with schizophrenia. Lower levels of glutamic acid decarboxylase 67 (GAD67) mRNA and protein, which is responsible for most cortical GABA synthesis, are accompanied by lower levels of GABA membrane transporter 1 (GAT1) mRNA. These alterations are thought to be most prominent in the parvalbumin (PV)-containing subclass of interneurons, which also contain lower levels of PV mRNA.

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Background: Levels of cannabinoid 1 receptor (CB1R) messenger RNA (mRNA) and protein, which are expressed most heavily in the cholecystokinin class of γ-aminobutyric acid (GABA) neurons, are lower in the dorsolateral prefrontal cortex in schizophrenia, and the magnitude of these differences is strongly correlated with that for glutamic acid decarboxylase 67 (GAD(67)) mRNA, a synthesizing enzyme for GABA. However, whether this correlation reflects a cause-effect relationship is unknown.

Methods: Using quantitative in situ hybridization, we measured CB1R, GAD(67), and diacylglycerol lipase alpha (the synthesizing enzyme for the endocannabinoid 2-arachidonoylglycerol) mRNA levels in the medial prefrontal cortex of genetically engineered GAD(67) heterozygous (GAD(67)(+/-)), CB1R heterozygous (CB1R(+/-)), CB1R knockout (CB1R(-/-)), and matched wild-type mice.

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Objective: Certain cognitive deficits in individuals with schizophrenia have been linked to disturbed gamma-aminobutyric acid (GABA) and glutamate neurotrans-mission in the prefrontal cortex. Thus, it is important to understand how the mechanisms that regulate GABA and glutamate neurotransmission are altered in schizophrenia. For example, group I metabo-tropic glutamate receptors (mGluR1α, mGluR5) modulate both GABA and gluta-mate systems.

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