797 research outputs found

    Bis(methacrylato-κO)bis­(2,4,6-trimethyl­pyridine-κN)copper(II)

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    In the monomeric title complex, [Cu(C4H5O2)2(C8H11N)2], the CuII atom lies on a centre of inversion. Its coordination by two substituted pyridine ligands and two carboxyl­ate anions leads to a slightly distorted trans-CuN2O2 square-planar geometry. The dihedral angle between the mean planes of the pyridine (py) ring and the carboxyl­ate group is 74.71 (7)°. The dihedral angles between the planar CuN2O2 core and the py ring and carboxyl­ate plane are 67.72 (5) and 89.95 (5)°, respectively. Based on the refined C=C and C—C bond lengths, the terminal =CH2 and –CH3 groups of the carboxyl­ate anion may be disordered, but the disorder could not be resolved in the present experiment. Several intra­molecular C—H⋯O inter­actions occur. In the crystal, mol­ecules are linked by weak C—H⋯O hydrogen bonds, generating chains propagating in [100]

    Consistency and diversity of spike dynamics in the neurons of bed nucleus of Stria Terminalis of the rat: a dynamic clamp study

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    Neurons display a high degree of variability and diversity in the expression and regulation of their voltage-dependent ionic channels. Under low level of synaptic background a number of physiologically distinct cell types can be identified in most brain areas that display different responses to standard forms of intracellular current stimulation. Nevertheless, it is not well understood how biophysically different neurons process synaptic inputs in natural conditions, i.e., when experiencing intense synaptic bombardment in vivo. While distinct cell types might process synaptic inputs into different patterns of action potentials representing specific "motifs'' of network activity, standard methods of electrophysiology are not well suited to resolve such questions. In the current paper we performed dynamic clamp experiments with simulated synaptic inputs that were presented to three types of neurons in the juxtacapsular bed nucleus of stria terminalis (jcBNST) of the rat. Our analysis on the temporal structure of firing showed that the three types of jcBNST neurons did not produce qualitatively different spike responses under identical patterns of input. However, we observed consistent, cell type dependent variations in the fine structure of firing, at the level of single spikes. At the millisecond resolution structure of firing we found high degree of diversity across the entire spectrum of neurons irrespective of their type. Additionally, we identified a new cell type with intrinsic oscillatory properties that produced a rhythmic and regular firing under synaptic stimulation that distinguishes it from the previously described jcBNST cell types. Our findings suggest a sophisticated, cell type dependent regulation of spike dynamics of neurons when experiencing a complex synaptic background. The high degree of their dynamical diversity has implications to their cooperative dynamics and synchronization

    What are Employers Looking for in New Veterinary Graduates? A Content Analysis of UK Veterinary Job Advertisements

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    As veterinary educators, we have a responsibility to ensure that our graduates are prepared for working life. Veterinary practices, like any other businesses, rely on good employees, and the implications of a poor match between newly employed veterinarian and employing practice could be extremely costly in terms of personal well-being and enjoyment of work as well as the time, financial, and goodwill costs of high staff turnover for the practice. Contemporary veterinary curricula encompass a range of teaching to complement the clinical content; including communication, teamwork, problem solving, and business skills, to support good practice and increase the employability of new graduates. Previous studies have examined the qualities required of early career veterinarians as viewed by educators, recent graduates, pet owners, and practitioners; however, nobody has previously constructed a picture of the employment market for new veterinary graduates by exploring the nature of its recruitment advertising. Three months of UK veterinary job advertisements were examined. Content analysis yielded 10 distinct characteristics desired by employers of early career veterinarians. The most common by far was “enthusiasm,” followed by an interest in a particular area of practice, being an “all-rounder” (i.e., having a broad range of skills), demonstrating good communication skills, teamwork, client care, and independence, as well as being caring, ambitious, and having high clinical standards. While several of these qualities are expected and are specifically taught in veterinary school, the dominance of “enthusiasm” as a specifically desired trait raises interesting questions about the characteristics of veterinary students who we are supporting, encouraging, or maybe even suppressing, during veterinary training

    Bi-allelic JAM2 Variants Lead to Early-Onset Recessive Primary Familial Brain Calcification.

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    Primary familial brain calcification (PFBC) is a rare neurodegenerative disorder characterized by a combination of neurological, psychiatric, and cognitive decline associated with calcium deposition on brain imaging. To date, mutations in five genes have been linked to PFBC. However, more than 50% of individuals affected by PFBC have no molecular diagnosis. We report four unrelated families presenting with initial learning difficulties and seizures and later psychiatric symptoms, cerebellar ataxia, extrapyramidal signs, and extensive calcifications on brain imaging. Through a combination of homozygosity mapping and exome sequencing, we mapped this phenotype to chromosome 21q21.3 and identified bi-allelic variants in JAM2. JAM2 encodes for the junctional-adhesion-molecule-2, a key tight-junction protein in blood-brain-barrier permeability. We show that JAM2 variants lead to reduction of JAM2 mRNA expression and absence of JAM2 protein in patient's fibroblasts, consistent with a loss-of-function mechanism. We show that the human phenotype is replicated in the jam2 complete knockout mouse (jam2 KO). Furthermore, neuropathology of jam2 KO mouse showed prominent vacuolation in the cerebral cortex, thalamus, and cerebellum and particularly widespread vacuolation in the midbrain with reactive astrogliosis and neuronal density reduction. The regions of the human brain affected on neuroimaging are similar to the affected brain areas in the myorg PFBC null mouse. Along with JAM3 and OCLN, JAM2 is the third tight-junction gene in which bi-allelic variants are associated with brain calcification, suggesting that defective cell-to-cell adhesion and dysfunction of the movement of solutes through the paracellular spaces in the neurovascular unit is a key mechanism in CNS calcification

    The Functional DRD3 Ser9Gly Polymorphism (rs6280) Is Pleiotropic, Affecting Reward as Well as Movement

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    Abnormalities of motivation and behavior in the context of reward are a fundamental component of addiction and mood disorders. Here we test the effect of a functional missense mutation in the dopamine 3 receptor (DRD3) gene (ser9gly, rs6280) on reward-associated dopamine (DA) release in the striatum. Twenty-six healthy controls (HCs) and 10 unmedicated subjects with major depressive disorder (MDD) completed two positron emission tomography (PET) scans with [11C]raclopride using the bolus plus constant infusion method. On one occasion subjects completed a sensorimotor task (control condition) and on another occasion subjects completed a gambling task (reward condition). A linear regression analysis controlling for age, sex, diagnosis, and self-reported anhedonia indicated that during receipt of unpredictable monetary reward the glycine allele was associated with a greater reduction in D2/3 receptor binding (i.e., increased reward-related DA release) in the middle (anterior) caudate (p<0.01) and the ventral striatum (p<0.05). The possible functional effect of the ser9gly polymorphism on DA release is consistent with previous work demonstrating that the glycine allele yields D3 autoreceptors that have a higher affinity for DA and display more robust intracellular signaling. Preclinical evidence indicates that chronic stress and aversive stimulation induce activation of the DA system, raising the possibility that the glycine allele, by virtue of its facilitatory effect on striatal DA release, increases susceptibility to hyperdopaminergic responses that have previously been associated with stress, addiction, and psychosis

    Dispersed Activity during Passive Movement in the Globus Pallidus of the 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine (MPTP)-Treated Primate

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    Parkinson's disease is a neurodegenerative disorder manifesting in debilitating motor symptoms. This disorder is characterized by abnormal activity throughout the cortico-basal ganglia loop at both the single neuron and network levels. Previous neurophysiological studies have suggested that the encoding of movement in the parkinsonian state involves correlated activity and synchronized firing patterns. In this study, we used multi-electrode recordings to directly explore the activity of neurons from the globus pallidus of parkinsonian primates during passive limb movements and to determine the extent to which they interact and synchronize. The vast majority (80/103) of the recorded pallidal neurons responded to periodic flexion-extension movements of the elbow. The response pattern was sinusoidal-like and the timing of the peak response of the neurons was uniformly distributed around the movement cycle. The interaction between the neuronal activities was analyzed for 123 simultaneously recorded pairs of neurons. Movement-based signal correlation values were diverse and their mean was not significantly different from zero, demonstrating that the neurons were not activated synchronously in response to movement. Additionally, the difference in the peak responses phase of pairs of neurons was uniformly distributed, showing their independent firing relative to the movement cycle. Our results indicate that despite the widely distributed activity in the globus pallidus of the parkinsonian primate, movement encoding is dispersed and independent rather than correlated and synchronized, thus contradicting current views that posit synchronous activation during Parkinson's disease

    Expanded syringe exchange programs and reduced HIV infection among new injection drug users in Tallinn, Estonia

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    <p>Abstract</p> <p>Background</p> <p>Estonia has experienced an HIV epidemic among intravenous drug users (IDUs) with the highest per capita HIV prevalence in Eastern Europe. We assessed the effects of expanded syringe exchange programs (SEP) in the capital city, Tallinn, which has an estimated 10,000 IDUs.</p> <p>Methods</p> <p>SEP implementation was monitored with data from the Estonian National Institute for Health Development. Respondent driven sampling (RDS) interview surveys with HIV testing were conducted in Tallinn in 2005, 2007 and 2009 (involving 350, 350 and 327 IDUs respectively). HIV incidence among new injectors (those injecting for < = 3 years) was estimated by assuming (1) new injectors were HIV seronegative when they began injecting, and (2) HIV infection occurred at the midpoint between first injection and time of interview.</p> <p>Results</p> <p>SEP increased from 230,000 syringes exchanged in 2005 to 440,000 in 2007 and 770,000 in 2009. In all three surveys, IDUs were predominantly male (80%), ethnic Russians (>80%), and young adults (mean ages 24 to 27 years). The proportion of new injectors decreased significantly over the years (from 21% in 2005 to 12% in 2009, p = 0.005). HIV prevalence among all respondents stabilized at slightly over 50% (54% in 2005, 55% in 2007, 51% in 2009), and decreased among new injectors (34% in 2005, 16% in 2009, p = 0.046). Estimated HIV incidence among new injectors decreased significantly from 18/100 person-years in 2005 and 21/100 person-years in 2007 to 9/100 person-years in 2009 (p = 0.026).</p> <p>Conclusions</p> <p>In Estonia, a transitional country, a decrease in the HIV prevalence among new injectors and in the numbers of people initiating injection drug use coincided with implementation of large-scale SEPs. Further reductions in HIV transmission among IDUs are still required. Provision of 70 or more syringes per IDU per year may be needed before significant reductions in HIV incidence occur.</p

    Deleterious variants in TRAK1 disrupt mitochondrial movement and cause fatal encephalopathy

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    This is the author accepted manuscript. The final version is available from Oxford University Press via the DOI in this record.The corrigendum to this article is in ORE: http://hdl.handle.net/10871/33588Cellular distribution and dynamics of mitochondria are regulated by several motor proteins and a microtubule network. In neurons, mitochondrial trafficking is crucial because of high energy needs and calcium ion buffering along axons to synapses during neurotransmission. The trafficking kinesin proteins (TRAKs) are well characterized for their role in lysosomal and mitochondrial trafficking in cells, especially neurons. Using whole exome sequencing, we identified homozygous truncating variants in TRAK1 (NM_001042646:c.287-2A > C), in six lethal encephalopathic patients from three unrelated families. The pathogenic variant results in aberrant splicing and significantly reduced gene expression at the RNA and protein levels. In comparison with normal cells, TRAK1-deficient fibroblasts showed irregular mitochondrial distribution, altered mitochondrial motility, reduced mitochondrial membrane potential, and diminished mitochondrial respiration. This study confirms the role of TRAK1 in mitochondrial dynamics and constitutes the first report of this gene in association with a severe neurodevelopmental disorder.D.M.E. and J.K. are supported by the Office of Naval Research (ONR) Grant N000141410538. M.S. is supported by the BBSRC (BB/K006231/1), a Wellcome Trust Institutional Strategic Support Award (WT097835MF, WT105618MA), and a Marie Curie Initial Training Network (ITN) action PerFuMe (316723). M.C.V.M., J.S., H.P., C.F., T.V. and W.A.G. are supported by the NGHRI Intramural Research Program. G.R. is supported by the Kahn Family Foundation and the Israeli Centers of Excellence (I-CORE) Program (ISF grant no. 41/11)

    The p250GAP Gene Is Associated with Risk for Schizophrenia and Schizotypal Personality Traits

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    BACKGROUND: Hypofunction of the glutamate N-Methyl-d-aspartate (NMDA) receptor has been implicated in the pathophysiology of schizophrenia. p250GAP is a brain-enriched NMDA receptor-interacting RhoGAP. p250GAP is involved in spine morphology, and spine morphology has been shown to be altered in the post-mortem brains of patients with schizophrenia. Schizotypal personality disorder has a strong familial relationship with schizophrenia. Several susceptibility genes for schizophrenia have been related to schizotypal traits. METHODS: We first investigated the association of eight linkage disequilibrium-tagging single-nucleotide polymorphisms (SNPs) that cover the p250GAP gene with schizophrenia in a Japanese sample of 431 schizophrenia patients and 572 controls. We then investigated the impact of the risk genetic variant in the p250GAP gene on schizotypal personality traits in 180 healthy subjects using the Schizotypal Personality Questionnaire. RESULTS: We found a significant difference in genotype frequency between the patients and the controls in rs2298599 (χ(2) = 17.6, p = 0.00015). The minor A/A genotype frequency of rs2298599 was higher in the patients (18%) than in the controls (9%) (χ(2) = 15.5, p = 0.000083). Moreover, we found that subjects with the rs2298599 risk A/A genotype, compared with G allele carriers, had higher scores of schizotypal traits (F(1,178) = 4.08, p = 0.045), particularly the interpersonal factor (F(1,178) = 5.85, p = 0.017). DISCUSSION: These results suggest that a genetic variation in the p250GAP gene might increase susceptibility not only for schizophrenia but also for schizotypal personality traits. We concluded that the p250GAP gene might be a new candidate gene for susceptibility to schizophrenia

    Spectrum of Phenotypic, Genetic, and Functional Characteristics in Patients With Epilepsy With KCNC2 Pathogenic Variants

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    Background and ObjectivesKCNC2 encodes Kv3.2, a member of the Shaw-related (Kv3) voltage-gated potassium channel subfamily, which is important for sustained high-frequency firing and optimized energy efficiency of action potentials in the brain. The objective of this study was to analyze the clinical phenotype, genetic background, and biophysical function of disease-associated Kv3.2 variants.MethodsIndividuals with KCNC2 variants detected by exome sequencing were selected for clinical, further genetic, and functional analysis. Cases were referred through clinical and research collaborations. Selected de novo variants were examined electrophysiologically in Xenopus laevis oocytes.ResultsWe identified novel KCNC2 variants in 18 patients with various forms of epilepsy, including genetic generalized epilepsy (GGE), developmental and epileptic encephalopathy (DEE) including early-onset absence epilepsy, focal epilepsy, and myoclonic-atonic epilepsy. Of the 18 variants, 10 were de novo and 8 were classified as modifying variants. Eight drug-responsive patients became seizure-free using valproic acid as monotherapy or in combination, including severe DEE cases. Functional analysis of 4 variants demonstrated gain of function in 3 severely affected DEE cases and loss of function in 1 case with a milder phenotype (GGE) as the underlying pathomechanisms.DiscussionThese findings implicate KCNC2 as a novel causative gene for epilepsy and emphasize the critical role of KV3.2 in the regulation of brain excitability
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