Prevalence of diabetic retinopathy and self-reported barriers to eye care among patients with diabetes in the emergency department: the diabetic retinopathy screening in the emergency department (DRS-ED) study.

BACKGROUND: Screening for diabetic retinopathy (DR) is suboptimal, and patients with diabetes who present to the emergency department (ED) may be at particularly high risk of undiagnosed DR. The purpose of this study is to determine the prevalence of DR among diabetic patients who present to the ED of our tertiary medical center using teleophthalmology and to assess self-reported barriers to eye care. METHODS: This cross-sectional, single-institution study recruited clinically stable diabetic patients who presented to the ED during daytime hours over 29 total weekdays across 2 months in 2018 and 2019. Participants had nonmydriatic, 45-degree, single-field digital retinal photographs taken on site (Digital Retinal System, Centervue). Following retinal imaging, participants then completed a survey about barriers to regular eye care and their acceptance of potential interventions to promote screening. Digital retinal photographs were interpreted remotely by a board-certified ophthalmologist and communicated to participants' primary care physician and/or endocrinologist. RESULTS: Over the study period, 275 ED patients had a documented diagnosis of diabetes, of whom 167 were deemed clinically stable for the study and 141 were invited to participate. Sixty-four were enrolled, of whom 50 had gradable-quality fundus images (78%). Of these 50 patients, almost all had type 2 diabetes (47, 94%), with an average disease duration of 12 ± 9 years and mean hemoglobin A1c of 8.1 ± 2.0% (mmol/mol). Based on fundus photography, 14 patients (28%) were diagnosed with DR, which was newly diagnosed for 10 (20% of the total study population). Severity was most commonly mild or moderate (12/14, 86%), with 1 case of severe nonproliferative DR and 1 proliferative DR. The majority (26, 52%) reported at least one barrier to routine eye care in our self-administered survey, of which having too many appointments (6, 12%) and cost (5, 10%) were frequently cited as most important. The majority were receptive to interventions to promote DR screening, including reminder phone calls (29, 58%) and text messages (28, 56%). CONCLUSIONS: Digital fundus photography in the ED detected a high rate of undiagnosed DR. Half of participants reported barriers to routine care, and most were receptive to messaging interventions to schedule an eye exam. Future studies are warranted to assess scalability of ED-based screening programs and their follow-through rates.

CB1-Dependent Long-Term Depression in Ventral Tegmental Area GABA Neurons: A Novel Target for Marijuana.

The VTA is necessary for reward behavior with dopamine cells critically involved in reward signaling. Dopamine cells in turn are innervated and regulated by neighboring inhibitory GABA cells. Using whole-cell electrophysiology in juvenile-adolescent GAD67-GFP male mice, we examined excitatory plasticity in fluorescent VTA GABA cells. A novel CB1-dependent LTD was induced in GABA cells that was dependent on metabotropic glutamate receptor 5, and cannabinoid receptor 1 (CB1). LTD was absent in CB1 knock-out mice but preserved in heterozygous littermates. Bath applied Δ9-tetrahydrocannabinol depressed GABA cell activity, therefore downstream dopamine cells will be disinhibited; and thus, this could potentially result in increased reward. Chronic injections of Δ9-tetrahydrocannabinol occluded LTD compared with vehicle injections; however, a single exposure was insufficient to do so. As synaptic modifications by drugs of abuse are often tied to addiction, these data suggest a possible mechanism for the addictive effects of Δ9-tetrahydrocannabinol in juvenile-adolescents, by potentially altering reward behavioral outcomes.SIGNIFICANCE STATEMENT The present study identifies a novel form of glutamatergic synaptic plasticity in VTA GABA neurons, a currently understudied cell type that is critical for the brain's reward circuit, and how Δ9-tetrahydrocannabinol occludes this plasticity. This study specifically addresses a potential unifying mechanism whereby marijuana could exert rewarding and addictive/withdrawal effects. Marijuana use and legalization are a pressing issue for many states in the United States. Although marijuana is the most commonly abused illicit drug, the implications of legalized, widespread, or continued usage are speculative. This study in juvenile-adolescent aged mice identifies a novel form of synaptic plasticity in VTA GABA cells, and the synaptic remodeling that can occur after Δ9-tetrahydrocannabinol use.

Human Connectome-Based Tractographic Atlas of the Brainstem Connections and Surgical Approaches.

BACKGROUND: The brainstem is one of the most challenging areas for the neurosurgeon because of the limited space between gray matter nuclei and white matter pathways. Diffusion tensor imaging-based tractography has been used to study the brainstem structure, but the angular and spatial resolution could be improved further with advanced diffusion magnetic resonance imaging (MRI). OBJECTIVE: To construct a high-angular/spatial resolution, wide-population-based, comprehensive tractography atlas that presents an anatomical review of the surgical approaches to the brainstem. METHODS: We applied advanced diffusion MRI fiber tractography to a population-based atlas constructed with data from a total of 488 subjects from the Human Connectome Project-488. Five formalin-fixed brains were studied for surgical landmarks. Luxol Fast Blue-stained histological sections were used to validate the results of tractography. RESULTS: We acquired the tractography of the major brainstem pathways and validated them with histological analysis. The pathways included the cerebellar peduncles, corticospinal tract, corticopontine tracts, medial lemniscus, lateral lemniscus, spinothalamic tract, rubrospinal tract, central tegmental tract, medial longitudinal fasciculus, and dorsal longitudinal fasciculus. Then, the reconstructed 3-dimensional brainstem structure was sectioned at the level of classic surgical approaches, namely supracollicular, infracollicular, lateral mesencephalic, perioculomotor, peritrigeminal, anterolateral (to the medulla), and retro-olivary approaches. CONCLUSION: The advanced diffusion MRI fiber tracking is a powerful tool to explore the brainstem neuroanatomy and to achieve a better understanding of surgical approaches. ABBREVIATIONS: CN, cranial nerveCPT, corticopontine tractCST, corticospinal tractCTT, central tegmental tractDLF, dorsal longitudinal fasciculusHCP, Human Connectome ProjectML, medial lemniscusMLF, medial longitudinal fasciculusRST, rubrospinal tractSTT, spinothalamic tract.