209 research outputs found

    Landscape Features, Human Disturbance or Prey Availability? What Shapes the Distribution of Large Carnivores in Europe?

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    Knowledge concerning the relative importance of biotic and abiotic factors associated with the long-term settlement of large carnivores in human-dominated landscapes is important for effective species conservation. However, identifying the major drivers of large carnivore occurrences at a continental scale is challenging as several factors can act in concert to affect large carnivore distributions. Thus, we investigated the relationship between the permanent and sporadic occurrences of large carnivores (brown bear, Eurasian lynx, grey wolf and wolverine) and three groups of predictor variables (i.e., landscape attributes, human disturbance and prey availability) on the continental scale in Europe. Specifically, we used generalized linear models (GLMs) and variation partitioning to estimate the independent and cumulative effects of the three predictor groups on large carnivore occurrences. The explained variance for permanent vs. sporadic occurrence was highest for the wolverine (42.8% and 29.7%), followed by the brown bear (20.5% and 16.4%), Eurasian lynx (15.2% and 11.6%) and grey wolf (15.8% and 6.1%). Landscape attributes, such as forest cover, shrub-land cover, altitude and slope, were positively related to the occurrence of grey wolf, brown bear and Eurasian lynx, whereas human disturbance (human population density, distance to roads and to human settlements) was negatively related to wolverine occurrence. For all species, shared effects between landscape attributes and human disturbance accounted for a considerable portion of the explained variation in both permanent and sporadic occurrence, and landscape attributes were generally more important for explaining permanent than sporadic occurrence, except for the wolverine. Prey availability was marginally associated with the permanent occurrence of the grey wolf but we found no statistical effect of prey availability on the occurrence of the other large carnivores. In conclusion, the sporadic occurrence of large carnivores in Europe is more stochastic and less predictable than their permanent occurrence. Landscape attributes and their joint effects with human disturbance are the most important factors related to the recolonization dynamics of large carnivores, although wolverine distributions appear strongly limited by human disturbance itself. Domestic prey availability seems to play a subordinate role in driving the recent distribution dynamics of large carnivores at the continental scale. Thus, our results are relevant also in light of the ongoing recolonization of large carnivores which, in many rural areas, caused concerns among the locals, especially in relation to conflicts with human activities. For these reasons, we stress the need to continue and improve large carnivore monitoring across Europe

    Inhibitory Effects of Cannabinoids on Acetylcholinesterase and Butyrylcholinesterase Enzyme Activities

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    Introduction: Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are two cholinergic enzymes catalyzing the reaction of cleaving acetylcholine into acetate and choline at the neuromuscular junction. Abnormal hyperactivity of AChE and BChE can lead to cholinergic deficiency, which is associated with several neurological disorders including cognitive decline and memory impairments. Preclinical studies support that some cannabinoids including cannabidiol (CBD) and tetrahydrocannabinol (THC) may exert pharmacological effects on the cholinergic system, but it remains unclear whether cannabinoids can inhibit AChE and BChE activities. Herein, we aimed to evaluate the inhibitory effects of a panel of cannabinoids including CBD, Δ8-THC, cannabigerol (CBG), cannabigerolic acid (CBGA), cannabicitran (CBT), cannabidivarin (CBDV), cannabichromene (CBC), and cannabinol (CBN) on AChE and BChE activities. Methods: The inhibitory effects of cannabinoids on the activities of AChE and BChE enzymes were evaluated with the Ellman method using acetyl- and butyryl-thiocholines as substrates. The inhibition mechanism of cannabinoids on AChE and BChE was studied with enzyme kinetic assays including the Lineweaver-Burk and Michaelis-Menten analyses. In addition, computational-based molecular docking experiments were performed to explore the interactions between the cannabinoids and the enzyme proteins. Results: Cannabinoids including CBD, Δ8-THC, CBG, CBGA, CBT, CBDV, CBC, and CBN (at 200 µM) inhibited the activities of AChE and BChE by 70.8, 83.7, 92.9, 76.7, 66.0, 79.3, 13.7, and 30.5%, and by 86.8, 80.8, 93.2, 87.1, 77.0, 78.5, 27.9, and 22.0%, respectively. The inhibitory effects of these cannabinoids (with IC50 values ranging from 85.2 to \u3e200 µM for AChE and 107.1 to \u3e200 µM for BChE) were less potent as compared to the positive control galantamine (IC50 1.21 and 6.86 µM for AChE and BChE, respectively). In addition, CBD, as a representative cannabinoid, displayed a competitive type of inhibition on both AChE and BChE. Data from the molecular docking studies suggested that cannabinoids interacted with several amino acid residues on the enzyme proteins, which supported their overall inhibitory effects on AChE and BChE. Conclusion: Cannabinoids showed moderate inhibitory effects on the activities of AChE and BChE enzymes, which may contribute to their modulatory effects on the cholinergic system. Further studies using cell-based and in vivo models are warranted to evaluate whether cannabinoids’ neuroprotective effects are associated with their anti-cholinesterase activities

    Identification of SARS-CoV-2 Main Protease Inhibitors from a Library of Minor Cannabinoids by Biochemical Inhibition Assay and Surface Plasmon Resonance Characterized Binding Affinity

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    The replication of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is mediated by its main protease (Mpro), which is a plausible therapeutic target for coronavirus disease 2019 (COVID-19). Although numerous in silico studies reported the potential inhibitory effects of natural products including cannabis and cannabinoids on SARS-CoV-2 Mpro, their anti-Mpro activities are not well validated by biological experimental data. Herein, a library of minor cannabinoids belonging to several chemotypes including tetrahydrocannabinols, cannabidiols, cannabigerols, cannabichromenes, cannabinodiols, cannabicyclols, cannabinols, and cannabitriols was evaluated for their anti-Mpro activity using a biochemical assay. Additionally, the binding affinities and molecular interactions between the active cannabinoids and the Mpro protein were studied by a biophysical technique (surface plasmon resonance; SPR) and molecular docking, respectively. Cannabinoids tetrahydrocannabutol and cannabigerolic acid were the most active Mpro inhibitors (IC50 = 3.62 and 14.40 μM, respectively) and cannabigerolic acid had a binding affinity KD=2.16×10−4 role= presentation \u3e=2.16×10−4 M). A preliminary structure and activity relationship study revealed that the anti-Mpro role= presentation \u3eMpro effects of cannabinoids were influenced by the decarboxylation of cannabinoids and the length of cannabinoids’ alkyl side chain. Findings from the biochemical, biophysical, and computational assays support the growing evidence of cannabinoids’ inhibitory effects on SARS-CoV-2 Mpro

    Predictors of survival in sporadic Creutzfeldt-Jakob disease and other human transmissible spongiform encephalopathies

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    A collaborative study of human transmissible spongiform encephalopathies has been carried out from 1993 to 2000 and includes data from 10 national registries, the majority in Western Europe. In this study, we present analyses of predictors of survival in sporadic (n = 2304), iatrogenic (n = 106) and variant Creutzfeldt-Jakob disease (n = 86) and in cases associated with mutations of the prion protein gene (n = 278), including Gerstmann-Sträussler-Scheinker syndrome (n = 24) and fatal familial insomnia (n = 41). Overall survival for each disease type was assessed by the Kaplan-Meier method and the multivariate analyses by the Cox proportional hazards model. In sporadic disease, longer survival was correlated with younger age at onset of illness, female gender, codon 129 heterozygosity, presence of CSF 14-3-3 protein and type 2a prion protein type. The ability to predict survival based on patient covariates is important for diagnosis and counselling, and the characterization of the survival distributions, in the absence of therapy, will be an important starting point for the assessment of potential therapeutic agents in the futur

    Postnatal Cytomegalovirus Infection and the Risk for Bronchopulmonary Dysplasia

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    Postnatally acquired cytomegalovirus (CMV) is typically benign in term infants but, in very low birth weight (VLBW) infants, can cause pneumonitis and sepsis-like illness. Whether postnatal CMV infection results in long-term pulmonary sequelae in these infants is unknown

    Weaning of Moderately Preterm Infants from the Incubator to the Crib: A Randomized Clinical Trial

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    OBJECTIVE: To assess whether length of hospital stay is decreased among moderately preterm infants weaned from incubator to crib at a lower vs higher weight. STUDY DESIGN: This trial was conducted in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network. Infants with gestational ages 29-33 weeks, birthweight <1600 g, and in an incubator were randomly assigned to a weaning weight of 1600 or 1800 g. Within 60 to 100 g of weaning weight, the incubator temperature was decreased by 1.0°C to 1.5°C every 24 hours until 28.0°C. The infants were weaned to the crib following stable temperature at 36.5°C to 37.4°C for 8 to 12 hours. Clothing and bedcoverings were standardized. The primary outcome was length of hospital stay from birth to discharge; secondary outcomes included length of stay and growth velocity from weaning to discharge. Adverse events were monitored. RESULTS: Of 1565 infants screened, 885 were eligible, and 366 enrolled-187 to the 1600-g and 179 to the 1800-g group. Maternal and neonatal characteristics did not differ among weight groups. Length of hospital stay was a median of 43 days in the lower and 41 days in the higher weight group (P = .12). Growth velocity from completion of weaning to discharge was higher in the lower weight group, 13.7 g/kg/day vs 12.8 g/kg/day (P = .005). Groups did not differ in adverse events. CONCLUSIONS: Among moderately preterm neonates, weaning from incubator to crib at a lower weight did not decrease length of stay, but was safe and was accompanied by higher weight gain after weaning

    Efficient Conversion of Astrocytes to Functional Midbrain Dopaminergic Neurons Using a Single Polycistronic Vector

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    Direct cellular reprogramming is a powerful new tool for regenerative medicine. In efforts to understand and treat Parkinson's Disease (PD), which is marked by the degeneration of dopaminergic neurons in the midbrain, direct reprogramming provides a valuable new source of these cells. Astrocytes, the most plentiful cells in the central nervous system, are an ideal starting population for the direct generation of dopaminergic neurons. In addition to their potential utility in cell replacement therapies for PD or in modeling the disease in vitro, astrocyte-derived dopaminergic neurons offer the prospect of direct in vivo reprogramming within the brain. As a first step toward this goal, we report the reprogramming of astrocytes to dopaminergic neurons using three transcription factors – ASCL1, LMX1B, and NURR1 – delivered in a single polycistronic lentiviral vector. The process is efficient, with 18.2±1.5% of cells expressing markers of dopaminergic neurons after two weeks. The neurons exhibit expression profiles and electrophysiological characteristics consistent with midbrain dopaminergic neurons, notably including spontaneous pacemaking activity, stimulated release of dopamine, and calcium oscillations. The present study is the first demonstration that a single vector can mediate reprogramming to dopaminergic neurons, and indicates that astrocytes are an ideal starting population for the direct generation of dopaminergic neurons
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