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Impaired olfaction and reduced cholinergic nucleus 4 (Ch4) volume both predict greater cognitive decline in Parkinson's disease (PD). We examined the relationship between olfaction, longitudinal change in cholinergic basal forebrain nuclei and their target regions, and cognition in early PD.We analyzed a cohort of 97 PD participants from the Parkinson's Progression Markers Initiative with brain MRIs at baseline, 1 year, 2 years, and 4 years. Using probabilistic maps, regional grey matter density (GMD) was calculated for Ch4, cholinergic nuclei 1, 2, and 3 (Ch123), and their target regions.Baseline University of Pennsylvania Smell Identification Test score correlated with change in GMD of all regions of interest (all p 0.05). Rate of change of Ch4 GMD was correlated with rate of change of Ch123 (p = 0.034), cortex (p = 0.001), and amygdala GMD (p 0.001), but not hippocampus GMD (p = 0.38). Rate of change of Ch123 GMD was correlated with rate of change of cortex (p = 0.001) and hippocampus (p 0.001), but not amygdala GMD (p = 0.133). In a linear regression model including change in GMD of all regions of interest and age as predictors, change in cortex GMD (βˆImpaired olfaction is associated with degeneration of the cholinergic basal forebrain and bilateral cortex, amygdala, and hippocampus in PD. The relationship between impaired olfaction and cognitive decline may be mediated by greater atrophy of the cortex and hippocampus.

SUMMARYIn eukaryotes, linear motor proteins govern intracellular transport and organization. In bacteria, where linear motors are absent, the ParA/MinD (A/D) family of ATPases spatially organize an array of genetic- and protein-based cellular cargos. ParA is well known to segregate plasmids and chromosomes, as is MinD for its role in divisome positioning. Less studied is the growing list of ParA/MinD-like ATPases found across prokaryotes and involved in the spatial organization of diverse protein-based organelles, such as Bacterial Microcompartments (BMCs), flagella, chemotaxis clusters, and conjugation machinery. Given the fundamental nature of these processes in both cell survival and pathogenesis, the positioning of these cargos has been independently investigated to varying degrees in several organisms. However, it remains unknown whether multiple A/D ATPases can coexist and coordinate the positioning of such a diverse set of fundamental cargos in the same cell. If so, what are the mechanistic commonalities, variation, and specificity determinants that govern the positioning reaction for each cargo? Here, we find that over a third of sequenced bacteria encode multiple A/D ATPases. Among these bacteria, we identified several human pathogens as well as the experimentally tractable organism, Halothiobacillus neapolitanus, which encodes seven A/D ATPases. We directly demonstrate that five of these A/D ATPases are each dedicated to the spatial regulation of a single cellular cargo: the chromosome, the divisome, the carboxysome BMC, the flagellum, and the chemotaxis cluster. We identify putative specificity determinants that allow each A/D ATPase to position its respective cargo. Finally, we show how the deletion of one A/D ATPase can have indirect effects on the inheritance of a cargo actively positioned by another A/D ATPase, stressing the importance of understanding how organelle trafficking, chromosome segregation, and cell division are coordinated in bacterial cells. Together, our data show how multiple A/D ATPases coexist and function to position a diverse set of fundamental cargos in the same bacterial cell. With this knowledge, we anticipate the design of minimal autonomous positioning systems for natural- and synthetic-cargos in bacteria for synthetic biology and biomedical applications.

Human glucokinase (GK) is a principal regulating sensor of plasma glucose levels. Mutations that inactivate GK are linked to diabetes, and mutations that activate it are associated with hypoglycemia. Unique kinetic properties equip GK for its regulatory role: although it has weak basal affinity for glucose, positive cooperativity in its binding of glucose causes a rapid increase in catalytic activity when plasma glucose concentrations rise above euglycemic levels. In clinical trials, small molecule GK activators (GKAs) have been efficacious in lowering plasma glucose and enhancing glucose-stimulated insulin secretion, but they carry a risk of overly activating GK and causing hypoglycemia. The theoretical models proposed to date attribute the positive cooperativity of GK to the existence of distinct protein conformations that interconvert slowly and exhibit different affinities for glucose. Here we report the respective crystal structures of the catalytic complex of GK and of a GK-glucose complex in a wide open conformation. To assess conformations of GK in solution, we also carried out small angle x-ray scattering experiments. The results showed that glucose dose-dependently converts GK from an apo conformation to an active open conformation. Compared with wild type GK, activating mutants required notably lower concentrations of glucose to be converted to the active open conformation. GKAs decreased the level of glucose required for GK activation, and different compounds demonstrated distinct activation profiles. These results lead us to propose a modified mnemonic model to explain cooperativity in GK. Our findings may offer new approaches for designing GKAs with reduced hypoglycemic risk.

Background: Ramelteon is a selective MT1/MT2 melatonin receptor agonist indicated for the treatment of insomnia characterized by difficulty with sleep onset. Objective: The current analysis was conducted to determine the effectiveness of ramelteon 8 mg in reducing the time to fall asleep in older adults with severe baseline sleep-onset difficulties. Methods: Patients with severe sleep-onset difficulty (defined as subjective sleep latency [sSL] ≥60 minutes) who had received ramelteon 8 mg or placebo were selected from a previously published multicenter outpatient trial of 829 older adults (aged ≥65 years) with primary, chronic insomnia (according to Diagnostic and Statistical Manual of Mental Disorders [Fourth Edition, Text Revision] criteria). Patients received single-blind placebo for 7 days (baseline) before receiving double-blind ramelteon 8 mg or placebo nightly for 5 weeks (35 nights). A 7-day, single-blind, placebo washout period followed. The primary end point was mean sSL for nights 1 through 7 (week 1). The mean changes in sSL from baseline at weeks 3 and 5 were evaluated to assess sustained efficacy. Adverse events (AEs) were collected in this analysis for both the ramelteon 8-mg and placebo groups. Results: A total of 157 patients from the rameltcon 8-mg group (mean age, 72.7 years; 87 women, 70 men) and 170 patients from the placebo group (mean age, 72.3 years; 111 women, 59 men) met the entry criteria for this post hoc analysis. Ramelteon 8 mg significantly reduced sSL at week 1 compared with placebo (change from baseline, -23.2 vs -7.5 minutes; P = 0.002). This statistically significant improvement was sustained at week 3 (-33.7 vs -19.8 minutes; P = 0.005) and week 5 (-37.4 vs -17.1 minutes; P < 0.001). The incidence of AEs was low. The most commonly reported treatment-emergent AEs were dizziness (ramclteon, 8.9%; placebo, 7.1%), dysgeusia (ramelteon, 7.0%; placebo, 2.9%), myalgia (ramelteon, 6.4%; placebo, 3.5%), and headache (ramelteon, 5.1%; placebo, 5.9%). Conclusions: In this subset analysis of older adults with severe baseline sleep-onset difficulties, ramelteon 8 mg significantly and persistently reduced subjective reports of time to sleep onset during 5 weeks of nightly treatment. Ramelteon appeared to be an effective and well-tolerated treatment for these older adults with primary, chronic insomnia.

Background and purpose To evaluate the efficacy, safety, and dose response of Ramelteon, a novel highly selective MT 1 /MT 2 receptor agonist, in patients with chronic primary insomnia. Patients and methods A randomized, multicenter, double-blind, placebo-controlled, five-period crossover study design was performed. A total of 107 patients, aged 18–64 years, were randomized into a dosing sequence that included 4, 8, 16, and 32mg of ramelteon and placebo. Patients received all five treatments, with a 5- to 12-day washout period between treatments, and served as their own controls. Medication was administered 30min before habitual bedtime and polysomnographic monitoring. Next-day residual effects were assessed with two visual analog scales (mood and feeling), digit symbol substitution test (DSST), word-list memory tests (immediate recall and delayed recall), and a post-sleep questionnaire that ascertained patients' alertness and ability to concentrate. Results All tested doses of ramelteon resulted in statistically significant reductions in latency to persistent sleep (LPS) and increases in total sleep time (TST). No next-day residual effects were apparent at any dose, as compared with placebo. There were no differences in the number or type of adverse events between any active treatment and placebo group. The most commonly reported adverse events were headache, somnolence, and sore throat. Conclusions Ramelteon demonstrated a statistically significant reduction in LPS and a statistically significant increase in TST, with no apparent next-day residual effects, in patients with chronic primary insomnia.