query: MeCP2 influences the synaptic maturation of neurons.

title: Structural Homeostasis: Compensatory Adjustments of Dendritic Arbor Geometry in Response to Variations of Synaptic Input

text: As the nervous system develops, there is an inherent variability in the connections formed between differentiating neurons. Despite this variability, neural circuits form that are functional and remarkably robust. One way in which neurons deal with variability in their inputs is through compensatory, homeostatic changes in their electrical properties. Here, we show that neurons also make compensatory adjustments to their structure. We analysed the development of dendrites on an identified central neuron (aCC) in the late Drosophila embryo at the stage when it receives its first connections and first becomes electrically active. At the same time, we charted the distribution of presynaptic sites on the developing postsynaptic arbor. Genetic manipulations of the presynaptic partners demonstrate that the postsynaptic dendritic arbor adjusts its growth to compensate for changes in the activity and density of synaptic sites. Blocking the synthesis or evoked release of presynaptic neurotransmitter results in greater dendritic extension. Conversely, an increase in the density of presynaptic release sites induces a reduction in the extent of the dendritic arbor. These growth adjustments occur locally in the arbor and are the result of the promotion or inhibition of growth of neurites in the proximity of presynaptic sites. We provide evidence that suggest a role for the postsynaptic activity state of protein kinase A in mediating this structural adjustment, which modifies dendritic growth in response to synaptic activity. These findings suggest that the dendritic arbor, at least during early stages of connectivity, behaves as a homeostatic device that adjusts its size and geometry to the level and the distribution of input received. The growing arbor thus counterbalances naturally occurring variations in synaptic density and activity so as to ensure that an appropriate level of input is achieved.

title: Increased dendritic complexity and axonal length in cultured mouse cortical neurons overexpressing methyl-CpG-binding protein MeCP2

text: Rett syndrome is caused by loss-of-function mutations in the gene encoding the methyl DNA-binding factor MeCP2. As brain mass and neuronal complexity tend to be diminished in Rett patients, we tested whether MeCP2 directly influences the morphological complexity of developing neurons. Our results show that cultured mouse neurons overexpressing MeCP2beta (MECP2A) develop more complex morphologies, having longer axonal and dendritic processes, and an increased number of axonal and dendritic terminal endings. We then tested whether overexpressing a mutant form of MeCP2beta lacking its carboxyl terminus would elicit the same effects. Interestingly, while neurons overexpressing this mutant failed to enhance axonal and dendritic process elongation, the complexity of their axonal and dendritic processes remained significantly elevated. Taken together, these data support the hypothesis that MeCP2 directly regulates neuronal maturation and/or synaptogenesis, and provides evidence that MeCP2 may influence neuritic elongation and process branching through different mechanisms.

title: Layered hydrogels accelerate iPSC-derived neuronal maturation and reveal migration defects caused by MeCP2 dysfunction.

text: Probing a wide range of cellular phenotypes in neurodevelopmental disorders using patient-derived neural progenitor cells (NPCs) can be facilitated by 3D assays, as 2D systems cannot entirely recapitulate the arrangement of cells in the brain. Here, we developed a previously unidentified 3D migration and differentiation assay in layered hydrogels to examine how these processes are affected in neurodevelopmental disorders, such as Rett syndrome. Our soft 3D system mimics the brain environment and accelerates maturation of neurons from human induced pluripotent stem cell (iPSC)-derived NPCs, yielding electrophysiologically active neurons within just 3 wk. Using this platform, we revealed a genotype-specific effect of methyl-CpG-binding protein-2 (MeCP2) dysfunction on iPSC-derived neuronal migration and maturation (reduced neurite outgrowth and fewer synapses) in 3D layered hydrogels. Thus, this 3D system expands the range of neural phenotypes that can be studied in vitro to include those influenced by physical and mechanical stimuli or requiring specific arrangements of multiple cell types.

title: Brain-Specific Phosphorylation of MeCP2 Regulates Activity-Dependent Bdnf Transcription, Dendritic Growth, and Spine Maturation

text: Mutations or duplications in MECP2 cause Rett and Rett-like syndromes, neurodevelopmental disorders characterized by mental retardation, motor dysfunction, and autistic behaviors. MeCP2 is expressed in many mammalian tissues and functions as a global repressor of transcription; however, the molecular mechanisms by which MeCP2 dysfunction leads to the neural-specific phenotypes of RTT remain poorly understood. Here, we show that neuronal activity and subsequent calcium influx trigger the de novo phosphorylation of MeCP2 at serine 421 (S421) by a CaMKII-dependent mechanism. MeCP2 S421 phosphorylation is induced selectively in the brain in response to physiological stimuli. Significantly, we find that S421 phosphorylation controls the ability of MeCP2 to regulate dendritic patterning, spine morphogenesis, and the activity-dependent induction of Bdnf transcription. These findings suggest that, by triggering MeCP2 phosphorylation, neuronal activity regulates a program of gene expression that mediates nervous system maturation and that disruption of this process in individuals with mutations in MeCP2 may underlie the neural-specific pathology of RTT.

title: Synaptic Determinants of Rett Syndrome

text: There is mounting evidence showing that the structural and molecular organization of synaptic connections is affected both in human patients and in animal models of neurological and psychiatric diseases. As a consequence of these experimental observations, it has been introduced the concept of synapsopathies, a notion describing brain disorders of synaptic function and plasticity. A close correlation between neurological diseases and synaptic abnormalities is especially relevant for those syndromes including also mental retardation in their symptomatology, such as Rett syndrome (RS). RS (MIM312750) is an X-linked dominant neurological disorder that is caused in the majority of cases by mutations in methyl-CpG-binding protein 2 (MeCP2). This review will focus on the current knowledge of the synaptic alterations produced by mutations of the gene MeCP2 in mouse models of RS and will highlight prospects experimental therapies currently in use. Different experimental approaches have revealed that RS could be the consequence of an impairment in the homeostasis of synaptic transmission in specific brain regions. Indeed, several forms of experience-induced neuronal plasticity are impaired in the absence of MeCP2. Based on the results presented in this review, it is reasonable to propose that understanding how the brain is affected by diseases such as RS is at reach. This effort will bring us closer to identify the neurobiological bases of human cognition.

title: Optogenetics reveal delayed afferent synaptogenesis on grafted human-induced pluripotent stem cell-derived neural progenitors.

text: Reprogramming of somatic cells into pluripotency stem cell state has opened new opportunities in cell replacement therapy and disease modeling in a number of neurological disorders. It still remains unknown, however, to what degree the grafted human-induced pluripotent stem cells (hiPSCs) differentiate into a functional neuronal phenotype and if they integrate into the host circuitry. Here, we present a detailed characterization of the functional properties and synaptic integration of hiPSC-derived neurons grafted in an in vitro model of hyperexcitable epileptic tissue, namely organotypic hippocampal slice cultures (OHSCs), and in adult rats in vivo. The hiPSCs were first differentiated into long-term self-renewing neuroepithelial stem (lt-NES) cells, which are known to form primarily GABAergic neurons. When differentiated in OHSCs for 6 weeks, lt-NES cell-derived neurons displayed neuronal properties such as tetrodotoxin-sensitive sodium currents and action potentials (APs), as well as both spontaneous and evoked postsynaptic currents, indicating functional afferent synaptic inputs. The grafted cells had a distinct electrophysiological profile compared to host cells in the OHSCs with higher input resistance, lower resting membrane potential, and APs with lower amplitude and longer duration. To investigate the origin of synaptic afferents to the grafted lt-NES cell-derived neurons, the host neurons were transduced with Channelrhodopsin-2 (ChR2) and optogenetically activated by blue light. Simultaneous recordings of synaptic currents in grafted lt-NES cell-derived neurons using whole-cell patch-clamp technique at 6 weeks after grafting revealed limited synaptic connections from host neurons. Longer differentiation times, up to 24 weeks after grafting in vivo, revealed more mature intrinsic properties and extensive synaptic afferents from host neurons to the lt-NES cell-derived neurons, suggesting that these cells require extended time for differentiation/maturation and synaptogenesis. However, even at this later time point, the grafted cells maintained a higher input resistance. These data indicate that grafted lt-NES cell-derived neurons receive ample afferent input from the host brain. Since the lt-NES cells used in this study show a strong propensity for GABAergic differentiation, the host-to-graft synaptic afferents may facilitate inhibitory neurotransmitter release, and normalize hyperexcitable neuronal networks in brain diseases, for example, such as epilepsy.

title: Mild overexpression of MeCP2 causes a progressive neurological disorder in mice.

text: Mutations in the X-linked methyl-CpG-binding protein 2 (MECP2), encoding a transcriptional repressor, cause Rett syndrome and a variety of related neurodevelopmental disorders. The vast majority of mutations associated with human disease are loss-of-function mutations, but precisely what aspect of MeCP2 function is responsible for these phenotypes remains unknown. We overexpressed wild-type human protein in transgenic mice using a large genomic clone containing the entire human MECP2 locus. Detailed neurobehavioral and electrophysiological studies in transgenic line MeCP2(Tg1), which expresses MeCP2 at approximately 2-fold wild-type levels, demonstrated onset of phenotypes around 10 weeks of age. Surprisingly, these mice displayed enhanced motor and contextual learning and enhanced synaptic plasticity in the hippocampus. After 20 weeks of age, however, these mice developed seizures, became hypoactive and approximately 30% of them died by 1 year of age. These data demonstrate that MeCP2 levels must be tightly regulated in vivo, and that even mild overexpression of this protein is detrimental. Furthermore, these results support the possibility that duplications or gain-of-function mutations in MECP2 might underlie some cases of X-linked delayed-onset neurobehavioral disorders.

title: Neurite sprouting and synapse deterioration in the aging Caenorhabditis elegans nervous system.

text: Caenorhabditis elegans is a powerful model for analysis of the conserved mechanisms that modulate healthy aging. In the aging nematode nervous system, neuronal death and/or detectable loss of processes are not readily apparent, but because dendrite restructuring and loss of synaptic integrity are hypothesized to contribute to human brain decline and dysfunction, we combined fluorescence microscopy and electron microscopy (EM) to screen at high resolution for nervous system changes. We report two major components of morphological change in the aging C. elegans nervous system: (1) accumulation of novel outgrowths from specific neurons, and (2) physical decline in synaptic integrity. Novel outgrowth phenotypes, including branching from the main dendrite or new growth from somata, appear at a high frequency in some aging neurons, but not all. Mitochondria are often associated with age-associated branch sites. Lowered insulin signaling confers some maintenance of ALM and PLM neuron structural integrity into old age, and both DAF-16/FOXO and heat shock factor transcription factor HSF-1 exert neuroprotective functions. hsf-1 can act cell autonomously in this capacity. EM evaluation in synapse-rich regions reveals a striking decline in synaptic vesicle numbers and a diminution of presynaptic density size. Interestingly, old animals that maintain locomotory prowess exhibit less synaptic decline than same-age decrepit animals, suggesting that synaptic integrity correlates with locomotory healthspan. Our data reveal similarities between the aging C. elegans nervous system and mammalian brain, suggesting conserved neuronal responses to age. Dissection of neuronal aging mechanisms in C. elegans may thus influence the development of brain healthspan-extending therapies.

title: Presynaptically Localized Cyclic GMP-Dependent Protein Kinase 1 Is a Key Determinant of Spinal Synaptic Potentiation and Pain Hypersensitivity

text: Synaptic long-term potentiation (LTP) at spinal neurons directly communicating pain-specific inputs from the periphery to the brain has been proposed to serve as a trigger for pain hypersensitivity in pathological states. Previous studies have functionally implicated the NMDA receptor-NO pathway and the downstream second messenger, cGMP, in these processes. Because cGMP can broadly influence diverse ion-channels, kinases, and phosphodiesterases, pre- as well as post-synaptically, the precise identity of cGMP targets mediating spinal LTP, their mechanisms of action, and their locus in the spinal circuitry are still unclear. Here, we found that Protein Kinase G1 (PKG-I) localized presynaptically in nociceptor terminals plays an essential role in the expression of spinal LTP. Using the Cre-lox P system, we generated nociceptor-specific knockout mice lacking PKG-I specifically in presynaptic terminals of nociceptors in the spinal cord, but not in post-synaptic neurons or elsewhere (SNS-PKG-I(-/-) mice). Patch clamp recordings showed that activity-induced LTP at identified synapses between nociceptors and spinal neurons projecting to the periaqueductal grey (PAG) was completely abolished in SNS-PKG-I(-/-) mice, although basal synaptic transmission was not affected. Analyses of synaptic failure rates and paired-pulse ratios indicated a role for presynaptic PKG-I in regulating the probability of neurotransmitter release. Inositol 1,4,5-triphosphate receptor 1 and myosin light chain kinase were recruited as key phosphorylation targets of presynaptic PKG-I in nociceptive neurons. Finally, behavioural analyses in vivo showed marked defects in SNS-PKG-I(-/-) mice in several models of activity-induced nociceptive hypersensitivity, and pharmacological studies identified a clear contribution of PKG-I expressed in spinal terminals of nociceptors. Our results thus indicate that presynaptic mechanisms involving an increase in release probability from nociceptors are operational in the expression of synaptic LTP on spinal-PAG projection neurons and that PKG-I localized in presynaptic nociceptor terminals plays an essential role in this process to regulate pain sensitivity.

title: ErbB4-neuregulin signaling modulates synapse development and dendritic arborization through distinct mechanisms.

text: Perturbations in neuregulin-1 (NRG1)/ErbB4 function have been associated with schizophrenia. Affected patients exhibit altered levels of these proteins and display hypofunction of glutamatergic synapses as well as altered neuronal circuitry. However, the role of NRG1/ErbB4 in regulating synapse maturation and neuronal process formation has not been extensively examined. Here we demonstrate that ErbB4 is expressed in inhibitory interneurons at both excitatory and inhibitory postsynaptic sites. Overexpression of ErbB4 postsynaptically enhances size but not number of presynaptic inputs. Conversely, knockdown of ErbB4 using shRNA decreases the size of presynaptic inputs, demonstrating a specific role for endogenous ErbB4 in synapse maturation. Using ErbB4 mutant constructs, we demonstrate that ErbB4-mediated synapse maturation requires its extracellular domain, whereas its tyrosine kinase activity is dispensable for this process. We also demonstrate that depletion of ErbB4 decreases the number of primary neurites and that stimulation of ErbB4 using a soluble form of NRG1 results in exuberant dendritic arborization through activation of the tyrosine kinase domain of ErbB4 and the phosphoinositide 3-kinase pathway. These findings demonstrate that NRG1/ErbB4 signaling differentially regulates synapse maturation and dendritic morphology via two distinct mechanisms involving trans-synaptic signaling and tyrosine kinase activity, respectively.

title: Wnt7a signaling promotes dendritic spine growth and synaptic strength through Ca²⁺/Calmodulin-dependent protein kinase II.

text: The balance between excitatory and inhibitory synapses is crucial for normal brain function. Wnt proteins stimulate synapse formation by increasing synaptic assembly. However, it is unclear whether Wnt signaling differentially regulates the formation of excitatory and inhibitory synapses. Here, we demonstrate that Wnt7a preferentially stimulates excitatory synapse formation and function. In hippocampal neurons, Wnt7a increases the number of excitatory synapses, whereas inhibitory synapses are unaffected. Wnt7a or postsynaptic expression of Dishevelled-1 (Dvl1), a core Wnt signaling component, increases the frequency and amplitude of miniature excitatory postsynaptic currents (mEPSCs), but not miniature inhibitory postsynaptic currents (mIPSCs). Wnt7a increases the density and maturity of dendritic spines, whereas Wnt7a-Dvl1-deficient mice exhibit defects in spine morphogenesis and mossy fiber-CA3 synaptic transmission in the hippocampus. Using a postsynaptic reporter for Ca(2+)/Calmodulin-dependent protein kinase II (CaMKII) activity, we demonstrate that Wnt7a rapidly activates CaMKII in spines. Importantly, CaMKII inhibition abolishes the effects of Wnt7a on spine growth and excitatory synaptic strength. These data indicate that Wnt7a signaling is critical to regulate spine growth and synaptic strength through the local activation of CaMKII at dendritic spines. Therefore, aberrant Wnt7a signaling may contribute to neurological disorders in which excitatory signaling is disrupted.

title: Tyrosine phosphorylation regulates the endocytosis and surface expression of GluN3A-containing NMDA receptors.

text: Selective control of receptor trafficking provides a mechanism for remodeling the receptor composition of excitatory synapses, and thus supports synaptic transmission, plasticity, and development. GluN3A (formerly NR3A) is a nonconventional member of the NMDA receptor (NMDAR) subunit family, which endows NMDAR channels with low calcium permeability and reduced magnesium sensitivity compared with NMDARs comprising only GluN1 and GluN2 subunits. Because of these special properties, GluN3A subunits act as a molecular brake to limit the plasticity and maturation of excitatory synapses, pointing toward GluN3A removal as a critical step in the development of neuronal circuitry. However, the molecular signals mediating GluN3A endocytic removal remain unclear. Here we define a novel endocytic motif (YWL), which is located within the cytoplasmic C-terminal tail of GluN3A and mediates its binding to the clathrin adaptor AP2. Alanine mutations within the GluN3A endocytic motif inhibited clathrin-dependent internalization and led to accumulation of GluN3A-containing NMDARs at the cell surface, whereas mimicking phosphorylation of the tyrosine residue promoted internalization and reduced cell-surface expression as shown by immunocytochemical and electrophysiological approaches in recombinant systems and rat neurons in primary culture. We further demonstrate that the tyrosine residue is phosphorylated by Src family kinases, and that Src-activation limits surface GluN3A expression in neurons. Together, our results identify a new molecular signal for GluN3A internalization that couples the functional surface expression of GluN3A-containing receptors to the phosphorylation state of GluN3A subunits, and provides a molecular framework for the regulation of NMDAR subunit composition with implications for synaptic plasticity and neurodevelopment.

title: Leptin regulates glutamate and glucose transporters in hypothalamic astrocytes.

text: Glial cells perform critical functions that alter the metabolism and activity of neurons, and there is increasing interest in their role in appetite and energy balance. Leptin, a key regulator of appetite and metabolism, has previously been reported to influence glial structural proteins and morphology. Here, we demonstrate that metabolic status and leptin also modify astrocyte-specific glutamate and glucose transporters, indicating that metabolic signals influence synaptic efficacy and glucose uptake and, ultimately, neuronal function. We found that basal and glucose-stimulated electrical activity of hypothalamic proopiomelanocortin (POMC) neurons in mice were altered in the offspring of mothers fed a high-fat diet. In adulthood, increased body weight and fasting also altered the expression of glucose and glutamate transporters. These results demonstrate that whole-organism metabolism alters hypothalamic glial cell activity and suggest that these cells play an important role in the pathology of obesity.

title: Induction of human neuronal cells by defined transcription factors

text: Somatic cell nuclear transfer, cell fusion, or expression of lineage-specific factors have been shown to induce cell-fate changes in diverse somatic cell types. We recently observed that forced expression of a combination of three transcription factors, Brn2 (also known as Pou3f2), Ascl1 and Myt1l, can efficiently convert mouse fibroblasts into functional induced neuronal (iN) cells. Here we show that the same three factors can generate functional neurons from human pluripotent stem cells as early as 6 days after transgene activation. When combined with the basic helix-loop-helix transcription factor NeuroD1, these factors could also convert fetal and postnatal human fibroblasts into iN cells showing typical neuronal morphologies and expressing multiple neuronal markers, even after downregulation of the exogenous transcription factors. Importantly, the vast majority of human iN cells were able to generate action potentials and many matured to receive synaptic contacts when co-cultured with primary mouse cortical neurons. Our data demonstrate that non-neural human somatic cells, as well as pluripotent stem cells, can be converted directly into neurons by lineage-determining transcription factors. These methods may facilitate robust generation of patient-specific human neurons for in vitro disease modelling or future applications in regenerative medicine.

title: Mechanical coupling between transsynaptic N-cadherin adhesions and actin flow stabilizes dendritic spines

text: The morphology of neuronal dendritic spines is a critical indicator of synaptic function. It is regulated by several factors, including the intracellular actin/myosin cytoskeleton and transcellular N-cadherin adhesions. To examine the mechanical relationship between these molecular components, we performed quantitative live-imaging experiments in primary hippocampal neurons. We found that actin turnover and structural motility were lower in dendritic spines than in immature filopodia and increased upon expression of a nonadhesive N-cadherin mutant, resulting in an inverse relationship between spine motility and actin enrichment. Furthermore, the pharmacological stimulation of myosin II induced the rearward motion of actin structures in spines, showing that myosin II exerts tension on the actin network. Strikingly, the formation of stable, spine-like structures enriched in actin was induced at contacts between dendritic filopodia and N-cadherin-coated beads or micropatterns. Finally, computer simulations of actin dynamics mimicked various experimental conditions, pointing to the actin flow rate as an important parameter controlling actin enrichment in dendritic spines. Together these data demonstrate that a clutch-like mechanism between N-cadherin adhesions and the actin flow underlies the stabilization of dendritic filopodia into mature spines, a mechanism that may have important implications in synapse initiation, maturation, and plasticity in the developing brain.

title: Neuronal circuitry mechanism regulating adult quiescent neural stem cell fate decision

text: Adult neurogenesis arises from neural stem cells within specialized niches. Neuronal activity and experience, presumably acting on this local niche, regulate multiple stages of adult neurogenesis, from neural progenitor proliferation to new neuron maturation, synaptic integration and survival. It is unknown whether local neuronal circuitry has a direct impact on adult neural stem cells. Here we show that, in the adult mouse hippocampus, nestin-expressing radial glia-like quiescent neural stem cells (RGLs) respond tonically to the neurotransmitter γ-aminobutyric acid (GABA) by means of γ2-subunit-containing GABAA receptors. Clonal analysis of individual RGLs revealed a rapid exit from quiescence and enhanced symmetrical self-renewal after conditional deletion of γ2. RGLs are in close proximity to terminals expressing 67-kDa glutamic acid decarboxylase (GAD67) of parvalbumin-expressing (PV+) interneurons and respond tonically to GABA released from these neurons. Functionally, optogenetic control of the activity of dentate PV+ interneurons, but not that of somatostatin-expressing or vasoactive intestinal polypeptide (VIP)-expressing interneurons, can dictate the RGL choice between quiescence and activation. Furthermore, PV+ interneuron activation restores RGL quiescence after social isolation, an experience that induces RGL activation and symmetrical division. Our study identifies a niche cell–signal–receptor trio and a local circuitry mechanism that control the activation and self-renewal mode of quiescent adult neural stem cells in response to neuronal activity and experience.

title: Tyrosine phosphorylation and regulation of the AMPA receptor by SRC family tyrosine kinases.

text: Phosphorylation of AMPA receptors is a major mechanism for the regulation of receptor function and underlies several forms of synaptic plasticity in the CNS. Although serine and threonine phosphorylation of AMPA receptors has been well studied, the potential role of tyrosine phosphorylation of AMPA receptors has not been investigated. Here, we show that the GluR2 subunit of AMPA receptors is tyrosine phosphorylated in vitro and in vivo by Src family tyrosine kinases on tyrosine 876 near its C terminus. In addition, GluR agonist treatment of cultured cortical neurons increased phosphorylation of tyrosine 876. The association with GluR2-interacting molecules GRIP1/2 was decreased by tyrosine phosphorylation of GluR2, whereas PICK1 interaction was not influenced. Moreover, mutation of tyrosine 876 eliminated AMPA- and NMDA-induced internalization of the GluR2 subunit. These data indicate that tyrosine phosphorylation of tyrosine 876 on the GluR2 C terminus by Src family tyrosine kinases is important for the regulation of AMPA receptor function and may be important for synaptic plasticity.

title: Specificity of sensory–motor connections encoded by Sema3e–Plxnd1 recognition

text: Spinal reflexes are mediated by synaptic connections between sensory afferents and motor neurons. The organization of these circuits shows several levels of specificity. Only certain classes of proprioceptive sensory neurons make direct, monosynaptic connections with motor neurons. Those that do are bound by rules of motor pool specificity: they form strong connections with motor neurons supplying the same muscle, but avoid motor pools supplying antagonistic muscles. This pattern of connectivity is initially accurate and is maintained in the absence of activity, implying that wiring specificity relies on the matching of recognition molecules on the surface of sensory and motor neurons. However, determinants of fine synaptic specificity here, as in most regions of the central nervous system, have yet to be defined. To address the origins of synaptic specificity in these reflex circuits we have used molecular genetic methods to manipulate recognition proteins expressed by subsets of sensory and motor neurons. We show here that a recognition system involving expression of the class 3 semaphorin Sema3e by selected motor neuron pools, and its high-affinity receptor plexin D1 (Plxnd1) by proprioceptive sensory neurons, is a critical determinant of synaptic specificity in sensory–motor circuits in mice. Changing the profile of Sema3e–Plxnd1 signalling in sensory or motor neurons results in functional and anatomical rewiring of monosynaptic connections, but does not alter motor pool specificity. Our findings indicate that patterns of monosynaptic connectivity in this prototypic central nervous system circuit are constructed through a recognition program based on repellent signalling.

title: Wnt signaling establishes anteroposterior neuronal polarity and requires retromer in C. elegans.

text: Secreted Wnt proteins influence neural connectivity by regulating axon guidance, dendritic morphogenesis and synapse formation. We report a new role for Wnt and Frizzled proteins in establishing the anteroposterior polarity of the mechanosensory neurons ALM and PLM in C. elegans. Disruption of Wnt signaling leads to a complete inversion of ALM and PLM polarity: the anterior process adopts the length, branching pattern and synaptic properties of the wild-type posterior process, and vice versa. Different but overlapping sets of Wnt proteins regulate neuronal polarity in different body regions. Wnts act directly on PLM via the Frizzled LIN-17. In addition, we show that they are needed for axon branching and anteriorly directed axon growth. We also find that the retromer, a conserved protein complex that mediates transcytosis and endosome-to-Golgi protein trafficking, plays a key role in Wnt signaling. Deletion mutations of retromer subunits cause ALM and PLM polarity, and other Wnt-related defects. We show that retromer protein VPS-35 is required in Wnt-expressing cells and propose that retromer activity is needed to generate a fully active Wnt signal.

title: Synaptic islands defined by the territory of a single astrocyte.

text: In the mammalian brain, astrocytes modulate neuronal function, in part, by synchronizing neuronal firing and coordinating synaptic networks. Little, however, is known about how this is accomplished from a structural standpoint. To investigate the structural basis of astrocyte-mediated neuronal synchrony and synaptic coordination, the three-dimensional relationships between cortical astrocytes and neurons was investigated. Using a transgenic and viral approach to label astrocytes with enhanced green fluorescent protein, we performed a three-dimensional reconstruction of astrocytes from tissue sections or live animals in vivo. We found that cortical astrocytes occupy nonoverlapping territories similar to those described in the hippocampus. Using immunofluorescence labeling of neuronal somata, a single astrocyte enwraps on average four neuronal somata with an upper limit of eight. Single-neuron dye-fills allowed us to estimate that one astrocyte contacts 300-600 neuronal dendrites. Together with the recent findings showing that glial Ca2+ signaling is restricted to individual astrocytes in vivo, and that Ca2+ signaling leads to gliotransmission, we propose the concept of functional islands of synapses in which groups of synapses confined within the boundaries of an individual astrocyte are modulated by the gliotransmitter environment controlled by that astrocyte. Our description offers a new structurally based conceptual framework to evaluate functional data involving interactions between neurons and astrocytes in the mammalian brain.

title: Neuromodulation of neurons and synapses.

text: Neuromodulation underlies the flexibility of neural circuit operation and behavior. Individual neuromodulators can have divergent actions in a neuron by targeting multiple physiological mechanisms. Conversely, multiple neuromodulators may have convergent actions through overlapping targets. The divergent and convergent neuromodulator actions can be unambiguously synergistic or antagonistic, but neuromodulation often entails balanced adjustment of nonlinear membrane and synaptic properties by targeting ion channel and synaptic dynamics rather than just excitability or synaptic strength. In addition, neuromodulators can exert effects at multiple timescales, from short-term adjustments of neuron and synapse function to persistent long-term regulation. This short review summarizes some highlights of the diverse actions of neuromodulators on ion channel and synaptic properties.


query: Measuring routine outcomes is more beneficial to clinical practice than assessing treatment adherence.

title: Anxiety

text:
OBJECTIVES To examine the effect of routinely administered psychiatric questionnaires on the recognition, management, and outcome of psychiatric disorders in non-psychiatric settings.
 DATA SOURCES Embase, Medline, PsycLIT, Cinahl, Cochrane Controlled Trials Register, and hand searches of key journals.
 METHODS A systematic review of randomised controlled trials of the administration and routine feedback of psychiatric screening and outcome questionnaires to clinicians in non-psychiatric settings. Narrative overview of key design features and end points, together with a random effects quantitative synthesis of comparable studies.
 MAIN OUTCOME MEASURES Recognition of psychiatric disorders after feedback of questionnaire results; interventions for psychiatric disorders; and outcome of psychiatric disorders.
 RESULTS Nine randomised studies were identified that examined the use of common psychiatric instruments in primary care and general hospital settings. Studies compared the effect of the administration of these instruments followed by the feedback of the results to clinicians, with administration with no feedback. Meta-analytic pooling was possible for four of these studies (2457 participants), which measured the effect of feedback on the recognition of depressive disorders. Routine administration and feedback of scores for all patients (irrespective of score) did not increase the overall rate of recognition of mental disorders such as anxiety and depression (relative risk of detection of depression by clinician after feedback 0.95, 95% confidence interval 0.83 to 1.09). Two studies showed that routine administration followed by selective feedback for only high scorers increased the rate of recognition of depression (relative risk of detection of depression after feedback 2.64, 1.62 to 4.31). This increased recognition, however, did not translate into an increased rate of intervention. Overall, studies of routine administration of psychiatric measures did not show an effect on patient outcome.
 CONCLUSIONS The routine measurement of outcome is a costly exercise. Little evidence shows that it is of benefit in improving psychosocial outcomes of those with psychiatric disorder managed in non-psychiatric settings.

title: Bariatric Surgery in the United Kingdom: A Cohort Study of Weight Loss and Clinical Outcomes in Routine Clinical Care.

text:
BACKGROUND Bariatric surgery is becoming a more widespread treatment for obesity. Comprehensive evidence of the long-term effects of contemporary surgery on a broad range of clinical outcomes in large populations treated in routine clinical practice is lacking. The objective of this study was to measure the association between bariatric surgery, weight, body mass index, and obesity-related co-morbidities.
 METHODS AND FINDINGS This was an observational retrospective cohort study using data from the United Kingdom Clinical Practice Research Datalink. All 3,882 patients registered in the database and with bariatric surgery on or before 31 December 2014 were included and matched by propensity score to 3,882 obese patients without surgery. The main outcome measures were change in weight and body mass index over 4 y; incident diagnoses of type 2 diabetes mellitus (T2DM), hypertension, angina, myocardial infarction (MI), stroke, fractures, obstructive sleep apnoea, and cancer; mortality; and resolution of hypertension and T2DM. Weight measures were available for 3,847 patients between 1 and 4 mo, 2,884 patients between 5 and 12 mo, and 2,258 patients between 13 and 48 mo post-procedure. Bariatric surgery patients exhibited rapid weight loss for the first four postoperative months, at a rate of 4.98 kg/mo (95% CI 4.88-5.08). Slower weight loss was sustained to the end of 4 y. Gastric bypass (6.56 kg/mo) and sleeve gastrectomy (6.29 kg/mo) were associated with greater initial weight reduction than gastric banding (2.77 kg/mo). Protective hazard ratios (HRs) were detected for bariatric surgery for incident T2DM, 0.68 (95% CI 0.55-0.83); hypertension, 0.35 (95% CI 0.27-0.45); angina, 0.59 (95% CI 0.40-0.87);MI, 0.28 (95% CI 0.10-0.74); and obstructive sleep apnoea, 0.55 (95% CI 0.40-0.87). Strong associations were found between bariatric surgery and the resolution of T2DM, with a HR of 9.29 (95% CI 6.84-12.62), and between bariatric surgery and the resolution of hypertension, with a HR of 5.64 (95% CI 2.65-11.99). No association was detected between bariatric surgery and fractures, cancer, or stroke. Effect estimates for mortality found no protective association with bariatric surgery overall, with a HR of 0.97 (95% CI 0.66-1.43). The data used were recorded for the management of patients in primary care and may be subject to inaccuracy, which would tend to lead to underestimates of true relative effect sizes.
 CONCLUSIONS Bariatric surgery as delivered in the UK healthcare system is associated with dramatic weight loss, sustained at least 4 y after surgery. This weight loss is accompanied by substantial improvements in pre-existing T2DM and hypertension, as well as a reduced risk of incident T2DM, hypertension, angina, MI, and obstructive sleep apnoea. Widening the availability of bariatric surgery could lead to substantial health benefits for many people who are morbidly obese.

title: The value of self-report assessment of adherence, rhinitis and smoking in relation to asthma control.

text:
AIMS To explore the utility of self-report measures of inhaled corticosteroid (ICS) adherence, degree of rhinitis and smoking status and their association with asthma control.
 METHODS Patients prescribed ICS for asthma at 85 UK practices were sent validated questionnaire measures of control (Asthma Control Questionnaire; ACQ) and adherence (Medication Adherence Report Scale), a two-item measure of smoking status, and a single-item measure of rhinitis.
 RESULTS Complete anonymised questionnaires were available for 3916 participants. Poor asthma control (ACQ >1.5) was associated with reported rhinitis (OR = 4.62; 95% CI: 3.71-5.77), smoking (OR = 4.33; 95% CI: 3.58-5.23) and low adherence to ICS (OR = 1.35; 95% CI: 1.18-1.55). The degree of rhinitis was important, with those reporting severe rhinitis exhibiting the worst asthma control, followed by those reporting mild rhinitis and then those reporting no rhinitis symptoms (F(2, 3913)=128.7, p<.001). There was a relationship between the number of cigarettes smoked each day and asthma control (F(5,655)=6.08, p<.001).
 CONCLUSIONS Poor asthma control is associated with self-reported rhinitis, smoking and low medication adherence. These potentially modifiable predictors of poor asthma control can be identified through a brief self-report questionnaire, used routinely as part of an asthma review.

title: Cognitive behavioral therapy vs zopiclone for treatment of chronic primary insomnia in older adults: a randomized controlled trial.

text:
CONTEXT Insomnia is a common condition in older adults and is associated with a number of adverse medical, social, and psychological consequences. Previous research has suggested beneficial outcomes of both psychological and pharmacological treatments, but blinded placebo-controlled trials comparing the effects of these treatments are lacking.
 OBJECTIVE To examine short- and long-term clinical efficacy of cognitive behavioral therapy (CBT) and pharmacological treatment in older adults experiencing chronic primary insomnia.
 DESIGN, SETTING, AND PARTICIPANTS A randomized, double-blinded, placebo-controlled trial of 46 adults (mean age, 60.8 y; 22 women) with chronic primary insomnia conducted between January 2004 and December 2005 in a single Norwegian university-based outpatient clinic for adults and elderly patients.
 INTERVENTION CBT (sleep hygiene, sleep restriction, stimulus control, cognitive therapy, and relaxation; n = 18), sleep medication (7.5-mg zopiclone each night; n = 16), or placebo medication (n = 12). All treatment duration was 6 weeks, and the 2 active treatments were followed up at 6 months.
 MAIN OUTCOME MEASURES Ambulant clinical polysomnographic data and sleep diaries were used to determine total wake time, total sleep time, sleep efficiency, and slow-wave sleep (only assessed using polysomnography) on all 3 assessment points.
 RESULTS CBT resulted in improved short- and long-term outcomes compared with zopiclone on 3 out of 4 outcome measures. For most outcomes, zopiclone did not differ from placebo. Participants receiving CBT improved their sleep efficiency from 81.4% at pretreatment to 90.1% at 6-month follow-up compared with a decrease from 82.3% to 81.9% in the zopiclone group. Participants in the CBT group spent much more time in slow-wave sleep (stages 3 and 4) compared with those in other groups, and spent less time awake during the night. Total sleep time was similar in all 3 groups; at 6 months, patients receiving CBT had better sleep efficiency using polysomnography than those taking zopiclone.
 CONCLUSION These results suggest that interventions based on CBT are superior to zopiclone treatment both in short- and long-term management of insomnia in older adults.
 TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00295386.

title: Equity in adherence to antiretroviral therapy among economically vulnerable adolescents living with HIV in Uganda

text: Studies from sub-Saharan Africa indicate that children made vulnerable by poverty have been disproportionately affected by HIV with many exposed via mother-to-child transmission. For youth living with HIV, adherence to life-saving treatment regimens are likely to be affected by the complex set of economic and social circumstances that challenge their families and also exacerbate health problems. Using baseline data from the National Institute of Child and Human Development (NICHD) funded Suubi+Adherence study, we examined the extent to which individual and composite measures of equity predict self-reported adherence among Ugandan adolescents aged 10-16 (n = 702) living with HIV. Results showed that greater asset ownership, specifically familial possession of seven or more tangible assets, was associated with greater odds of self-reported adherence (OR 1.69, 95% CI: 1.00-2.85). Our analyses also indicated that distance to the nearest health clinic impacts youth's adherence to an ARV regimen. Youth who reported living nearest to a clinic were significantly more likely to report optimal adherence (OR 1.49, 95% CI: 0.92-2.40). Moreover, applying the composite equity scores, we found that adolescents with greater economic advantage in ownership of household assets, financial savings, and caregiver employment had higher odds of adherence by a factor of 1.70 (95% CI: 1.07-2.70). These findings suggest that interventions addressing economic and social inequities may be beneficial to increase antiretroviral therapy (ART) uptake among economically vulnerable youth, especially in sub-Saharan Africa. This is one of the first studies to address the question of equity in adherence to ART among economically vulnerable youth with HIV.

title: Hospital mortality, length of stay, and preventable complications among critically ill patients before and after tele-ICU reengineering of critical care processes.

text:
CONTEXT The association of an adult tele-intensive care unit (ICU) intervention with hospital mortality, length of stay, best practice adherence, and preventable complications for an academic medical center has not been reported.
 OBJECTIVE To quantify the association of a tele-ICU intervention with hospital mortality, length of stay, and complications that are preventable by adherence to best practices.
 DESIGN, SETTING, AND PATIENTS Prospective stepped-wedge clinical practice study of 6290 adults admitted to any of 7 ICUs (3 medical, 3 surgical, and 1 mixed cardiovascular) on 2 campuses of an 834-bed academic medical center that was performed from April 26, 2005, through September 30, 2007. Electronically supported and monitored processes for best practice adherence, care plan creation, and clinician response times to alarms were evaluated.
 MAIN OUTCOME MEASURES Case-mix and severity-adjusted hospital mortality. Other outcomes included hospital and ICU length of stay, best practice adherence, and complication rates.
 RESULTS The hospital mortality rate was 13.6% (95% confidence interval [CI], 11.9%-15.4%) during the preintervention period compared with 11.8% (95% CI, 10.9%-12.8%) during the tele-ICU intervention period (adjusted odds ratio [OR], 0.40 [95% CI, 0.31-0.52]). The tele-ICU intervention period compared with the preintervention period was associated with higher rates of best clinical practice adherence for the prevention of deep vein thrombosis (99% vs 85%, respectively; OR, 15.4 [95% CI, 11.3-21.1]) and prevention of stress ulcers (96% vs 83%, respectively; OR, 4.57 [95% CI, 3.91-5.77], best practice adherence for cardiovascular protection (99% vs 80%, respectively; OR, 30.7 [95% CI, 19.3-49.2]), prevention of ventilator-associated pneumonia (52% vs 33%, respectively; OR, 2.20 [95% CI, 1.79-2.70]), lower rates of preventable complications (1.6% vs 13%, respectively, for ventilator-associated pneumonia [OR, 0.15; 95% CI, 0.09-0.23] and 0.6% vs 1.0%, respectively, for catheter-related bloodstream infection [OR, 0.50; 95% CI, 0.27-0.93]), and shorter hospital length of stay (9.8 vs 13.3 days, respectively; hazard ratio for discharge, 1.44 [95% CI, 1.33-1.56]). The results for medical, surgical, and cardiovascular ICUs were similar.
 CONCLUSION In a single academic medical center study, implementation of a tele-ICU intervention was associated with reduced adjusted odds of mortality and reduced hospital length of stay, as well as with changes in best practice adherence and lower rates of preventable complications.

title: Effectiveness of thigh-length graduated compression stockings to reduce the risk of deep vein thrombosis after stroke (CLOTS trial 1): a multicentre, randomised controlled trial

text:
BACKGROUND Deep vein thrombosis (DVT) and pulmonary embolism are common after stroke. In small trials of patients undergoing surgery, graduated compression stockings (GCS) reduce the risk of DVT. National stroke guidelines extrapolating from these trials recommend their use in patients with stroke despite insufficient evidence. We assessed the effectiveness of thigh-length GCS to reduce DVT after stroke.
 METHODS In this outcome-blinded, randomised controlled trial, 2518 patients who were admitted to hospital within 1 week of an acute stroke and who were immobile were enrolled from 64 centres in the UK, Italy, and Australia. Patients were allocated via a central randomisation system to routine care plus thigh-length GCS (n=1256) or to routine care plus avoidance of GCS (n=1262). A technician who was blinded to treatment allocation undertook compression Doppler ultrasound of both legs at about 7-10 days and, when practical, again at 25-30 days after enrolment. The primary outcome was the occurrence of symptomatic or asymptomatic DVT in the popliteal or femoral veins. Analyses were by intention to treat. This study is registered, number ISRCTN28163533.
 FINDINGS All patients were included in the analyses. The primary outcome occurred in 126 (10.0%) patients allocated to thigh-length GCS and in 133 (10.5%) allocated to avoid GCS, resulting in a non-significant absolute reduction in risk of 0.5% (95% CI -1.9% to 2.9%). Skin breaks, ulcers, blisters, and skin necrosis were significantly more common in patients allocated to GCS than in those allocated to avoid their use (64 [5%] vs 16 [1%]; odds ratio 4.18, 95% CI 2.40-7.27).
 INTERPRETATION These data do not lend support to the use of thigh-length GCS in patients admitted to hospital with acute stroke. National guidelines for stroke might need to be revised on the basis of these results.
 FUNDING Medical Research Council (UK), Chief Scientist Office of Scottish Government, Chest Heart and Stroke Scotland, Tyco Healthcare (Covidien) USA, and UK Stroke Research Network.

title: Malaria risk perception, knowledge and prophylaxis practices among travellers of African ethnicity living in Paris and visiting their country of origin in sub-Saharan Africa.

text: An observational prospective cohort study assessed malaria risk perception, knowledge and prophylaxis practices among individuals of African ethnicity living in Paris and travelling to their country of origin to visit friends or relatives (VFR). The study compared two groups of VFR who had visited a travel clinic (TC; n=122) or a travel agency (TA; n=69) before departure. Of the 47% of VFR citing malaria as a health concern, 75% knew that malaria is mosquito-borne and that bed nets are an effective preventive measure. Perception of high malaria risk was greater in the TA group (33%) than in the TC group (7%). The availability of a malaria vaccine was mentioned by 35% of VFR, with frequent confusion between yellow fever vaccine and malaria prevention. Twenty-nine percent took adequate chemoprophylaxis with complete adherence, which was higher among the TC group (41%) than the TA group (12%). Effective antivector protection measures used were bed nets (16%), wearing long clothes at night (14%) and air conditioning (8%), with no differences between the study groups except in the use of impregnated bed nets (11% of the TC group and none of the TA group). Media coverage, malaria chemoprophylaxis repayment and cultural adaptation of preventive messages should be improved to reduce the high rate of inadequate malaria prophylaxis in VFR.

title: Effects of treatment for intestinal helminth infection on growth and cognitive performance in children: systematic review of randomised trials.

text:
OBJECTIVE To summarise the effects of anthelmintic drug treatment on growth and cognitive performance in children.
 DATA SOURCES Electronic databases: Cochrane Infectious Diseases Group controlled trial register, Cochrane controlled trials register, Embase, and Medline. Citations of all identified trials. Contact with the World Health Organization and field researchers.    REVIEW METHODS Systematic review of randomised controlled trials in children aged 1-16 that compared anthelmintic treatment with placebo or no treatment. Assessment of validity and data abstraction conducted independently by two reviewers.
 MAIN OUTCOME MEASURES Growth and cognitive performance.
 RESULTS Thirty randomised controlled trials in more than 15 000 children were identified. Effects on mean weight were unremarkable, and heterogeneity was evident in the results. There were some positive effects on mean weight change in the trials reporting this outcome: after a single dose (any anthelmintic) the pooled estimates were 0.24 kg (95% confidence interval 0.15 kg to 0. 32 kg; fixed effects model assumed) and 0.38 kg (0.01 kg to 0.77 kg; random effects model assumed). Results from trials of multiple doses showed mean weight change in up to one year of follow up of 0.10 kg (0.04 kg to 0.17 kg; fixed effects) or 0.15 kg (0.00 to 0.30; random effects). At more than one year of follow up, mean weight change was 0.12 kg (-0.02 kg to 0.26 kg; fixed effects) and 0.43 (-0.61 to 1. 47; random effects). Results from studies of cognitive performance were inconclusive.
 CONCLUSIONS There is some limited evidence that routine treatment of children in areas where helminths are common has effects on weight gain, but this is not consistent between trials. There is insufficient evidence as to whether this intervention improves cognitive performance.

title: Metformin-associated lactic acidosis: a rare or very rare clinical entity?

text:
AIMS Lactic acidosis is a well recognized complication of biguanide therapy which is potentially serious. Although the prevalence of metformin-associated lactic acidosis (MALA) is much lower than that associated with phenformin, it is still being reported sporadically which raises concerns for the practising clinicians. We review the currently available world-wide data of the prevalence of MALA, the risk factors for its development and the current practical guidelines on the use of metformin to minimize the risk of this potential hazard.
 METHODS An extensive literature search was conducted from both Medline and Ovid (1965-98) using the following keywords: 'Type 2 diabetes mellitus', 'oral hypoglycaemic drugs', 'biguanides', 'metformin-associated lactic acidosis' and 'renal impairment'.
 RESULTS MALA was found to be a very rare clinical entity, being 20 times less common than phenformin-associated lactic acidosis. Amongst all the risk factors, renal impairment appears to be the major precipitating factor for the development of MALA in metformin-treated patients. We also found cases of MALA where no precipitating factors were identified and the underlying mechanism in these cases remains unclear. Practical recommendations of metformin use to minimize the risk of MALA have been listed based on previous reports.
 CONCLUSIONS The low prevalence of MALA is comparable to the prevalence of sulphonylurea-induced hypoglycaemia. Metformin has many beneficial metabolic effects in the management of Type 2 diabetes mellitus. Provided that the recommended guidelines for metformin use are strictly adhered to, its widespread use would be safe and the incidence of MALA will be further reduced.

title: Measuring adherence to highly active antiretroviral therapy: implications for research and practice.

text: Highly active antiretroviral therapy (HAART) has radically changed the course of HIV disease, producing substantial reductions in both HIV-related morbidity and mortality. However, the complexity of the typical daily HAART regimen is substantial, and high levels of adherence are essential for complete and long-term viral suppression and the avoidance of drug resistance. The complexity of HAART has made the assessment of medication adherence of paramount importance. Even though various methods are in use, each measures only a subset of adherence behaviors, and each measure has limited predictive validity. Given the individual and public health concerns associated with adherence to HAART, there is a need for the continued development and validation of measures of medication adherence.

title: Characterisation of antibiotic prescriptions for acute respiratory tract infections in Danish general practice: a retrospective registry based cohort study

text: Inappropriate use of antibiotics is contributing to the increasing rates of antimicrobial resistance. Several Danish guidelines on antibiotic prescribing for acute respiratory tract infections in general practice have been issued to promote rational prescribing of antibiotics, however it is unclear if these recommendations are followed. We aimed to characterise the pattern of antibiotic prescriptions for patients diagnosed with acute respiratory tract infections, by means of electronic prescriptions, labeled with clinical indications, from Danish general practice. Acute respiratory tract infections accounted for 456,532 antibiotic prescriptions issued between July 2012 and June 2013. Pneumonia was the most common indication with 178,354 prescriptions (39%), followed by acute tonsillitis (21%) and acute otitis media (19%). In total, penicillin V accounted for 58% of all prescriptions, followed by macrolides (18%) and amoxicillin (15%). The use of second-line agents increased with age for all indications, and comprised more than 40% of the prescriptions in patients aged >75 years. Women were more often prescribed antibiotics regardless of clinical indication. This is the first Danish study to characterise antibiotic prescription patterns for acute respiratory tract infections by data linkage of clinical indications. The findings confirm that penicillin V is the most commonly prescribed antibiotic agent for treatment of patients with an acute respiratory tract infection in Danish general practice. However, second-line agents like macrolides and amoxicillin with or without clavulanic acid are overused. Strategies to improve the quality of antibiotic prescribing especially for pneumonia, acute otitis media and acute rhinosinusitis are warranted.    RESPIRATORY TRACT INFECTIONS TRACKING THE OVERUSE OF ANTIBIOTICS: Better adherence to guidelines for prescribing antibiotics for different respiratory tract infections are warranted in Danish general practice. The over-use of antibiotics, particularly so-called 'second-line' agents such as amoxicillin, increases resistance and may lead to a potentially catastrophic scenario where antibiotics are no longer effective. Exactly how widespread the over-use of antibiotics is for different infections, however, is not clear. Rune Aabenhus at the University of Copenhagen and co-workers analyzed primary care data regarding antibiotic prescriptions for acute respiratory tract infections including pneumonia and ear infections in Denmark. They found that penicillin V-the current recommended first-line drug in Scandinavian countries-accounted for 58 per cent of prescriptions, a figure which should be improved. Amoxicillin and macrolides were over-prescribed, particularly in elderly patients. The team also call for further analysis of prescriptions given by out-of-hours clinics.

title: ART adherence clubs: A long-term retention strategy for clinically stable patients receiving antiretroviral therapy

text: The ART-adherence club model described here provides patient-friendly access to antiretroviral therapy (ART) for clinically stable patients. It reduces the burden that stable patients place on healthcare facilities, increasing clinical human resources for new patients, and those clinically unstable and at risk of failing treatment. In the model, 30 patients are allocated to an ART club. The group meets either at a facility or community venue for less than an hour every 2 months. Group meetings are facilitated by a lay club facilitator who provides a quick clinical assessment, referral where necessary, and dispenses pre-packed ART. From January 2011 to December 2012, after adoption for phased rollout by the Western Cape Government, more than 600 ART clubs were established in Cape Town, providing ART care to over 16 000 patients. This extensive, rapid rollout demonstrates active buy-in from patients and facility staff. South Africa should consider a similar model for national rollout.

title: Effect of Oral Semaglutide Compared With Placebo and Subcutaneous Semaglutide on Glycemic Control in Patients With Type 2 Diabetes: A Randomized Clinical Trial

text: Importance Glucagon-like peptide-1 (GLP-1) receptor agonists are effective therapies for the treatment of type 2 diabetes and are all currently available as an injection. Objectives To compare the effects of oral semaglutide with placebo (primary) and open-label subcutaneous semaglutide (secondary) on glycemic control in patients with type 2 diabetes. Design, Setting, and Patients Phase 2, randomized, parallel-group, dosage-finding, 26-week trial with 5-week follow-up at 100 sites (hospital clinics, general practices, and clinical research centers) in 14 countries conducted between December 2013 and December 2014. Of 1106 participants assessed, 632 with type 2 diabetes and insufficient glycemic control using diet and exercise alone or a stable dose of metformin were randomized. Randomization was stratified by metformin use. Interventions Once-daily oral semaglutide of 2.5 mg (n = 70), 5 mg (n = 70), 10 mg (n = 70), 20 mg (n = 70), 40-mg 4-week dose escalation (standard escalation; n = 71), 40-mg 8-week dose escalation (slow escalation; n = 70), 40-mg 2-week dose escalation (fast escalation, n = 70), oral placebo (n = 71; double-blind) or once-weekly subcutaneous semaglutide of 1.0 mg (n = 70) for 26 weeks. Main Outcomes and Measures The primary end point was change in hemoglobing A1c (HbA1c) from baseline to week 26. Secondary end points included change from baseline in body weight and adverse events. Results Baseline characteristics were comparable across treatment groups. Of the 632 randomized patients (mean age, 57.1 years [SD, 10.6]; men, 395 (62.7%); diabetes duration, 6.3 years [SD, 5.2]; body weight, 92.3 kg [SD, 16.8]; BMI, 31.7 [SD, 4.3]), 583 (92%) completed the trial. Mean change in HbA1c level from baseline to week 26 decreased with oral semaglutide (dosage-dependent range, −0.7% to −1.9%) and subcutaneous semaglutide (−1.9%) and placebo (−0.3%); oral semaglutide reductions were significant vs placebo (dosage-dependent estimated treatment difference [ETD] range for oral semaglutide vs placebo, –0.4% to –1.6%; P = .01 for 2.5 mg, <.001 for all other dosages). Reductions in body weight were greater with oral semaglutide (dosage-dependent range, −2.1 kg to −6.9 kg) and subcutaneous semaglutide (−6.4 kg) vs placebo (−1.2 kg), and significant for oral semaglutide dosages of 10 mg or more vs placebo (dosage-dependent ETD range, –0.9 to –5.7 kg; P < .001). Adverse events were reported by 63% to 86% (371 of 490 patients) in the oral semaglutide groups, 81% (56 of 69 patients) in the subcutaneous semaglutide group, and 68% (48 of 71 patients) in the placebo group; mild to moderate gastrointestinal events were most common. Conclusions and Relevance Among patients with type 2 diabetes, oral semaglutide resulted in better glycemic control than placebo over 26 weeks. These findings support phase 3 studies to assess longer-term and clinical outcomes, as well as safety. Trial Registration clinicaltrials.gov Identifier: NCT01923181

title: Cannabinoids in Clinical Practice

text: Cannabis has a potential for clinical use often obscured by unreliable and purely anecdotal reports. The most important natural cannabinoid is the psychoactive tetrahydrocannabinol (Δ9-THC); others include cannabidiol (CBD) and cannabigerol (CBG). Not all the observed effects can be ascribed to THC, and the other constituents may also modulate its action; for example CBD reduces anxiety induced by THC. A standardised extract of the herb may be therefore be more beneficial in practice and clinical trial protocols have been drawn up to assess this. The mechanism of action is still not fully understood, although cannabinoid receptors have been cloned and natural ligands identified. Cannabis is frequently used by patients with multiple sclerosis (MS) for muscle spasm and pain, and in an experimental model of MS low doses of cannabinoids alleviated tremor. Most of the controlled studies have been carried out with THC rather than cannabis herb and so do not mimic the usual clincal situation. Small clinical studies have confirmed the usefulness of THC as an analgesic; CBD and CBG also have analgesic and antiinflammatory effects, indicating that there is scope for developing drugs which do not have the psychoactive properties ofTHC. Patients taking the synthetic derivative nabilone for neurogenic pain actually preferred cannabis herb and reported that it relieved not only pain but the associated depression and anxiety. Cannabinoids are effective in chemotherapy-induced emesis and nabilone has been licensed for this use for several years. Currently, the synthetic cannabinoid HU211 is undergoing trials as a protective agent after brain trauma. Anecdotal reports of cannabis use include case studies in migraine and Tourette’s syndrome, and as a treatment for asthma and glaucoma. Apart from the smoking aspect, the safety profile of cannabis is fairly good. However, adverse reactions include panic or anxiety attacks, which are worse in the elderly and in women, and less likely in children. Although psychosis has been cited as a consequence of cannabis use, an examination of psychiatric hospital admissions found no evidence of this, however, it may exacerbate existing symptoms. The relatively slow elimination from the body of the cannabinoids has safety implications for cognitive tasks, especially driving and operating machinery; although driving impairment with cannabis is only moderate, there is a significant interaction with alcohol. Natural materials are highly variable and multiple components need to be standardised to ensure reproducible effects. Pure natural and synthetic compounds do not have these disadvantages but may not have the overall therapeutic effect of the herb.

title: Treatment of antidepressant-associated sexual dysfunction with sildenafil: a randomized controlled trial.

text:
CONTEXT Sexual dysfunction is a common adverse effect of antidepressants that frequently results in treatment noncompliance.
 OBJECTIVE To assess the efficacy of sildenafil citrate in men with sexual dysfunction associated with the use of selective and nonselective serotonin reuptake inhibitor (SRI) antidepressants.
 DESIGN, SETTING, AND PATIENTS Prospective, parallel-group, randomized, double-blind, placebo-controlled trial conducted between November 1, 2000, and January 1, 2001, at 3 US university medical centers among 90 male outpatients (mean [SD] age, 45 [8] years) with major depression in remission and sexual dysfunction associated with SRI antidepressant treatment.
 INTERVENTION Patients were randomly assigned to take sildenafil (n = 45) or placebo (n = 45) at a flexible dose starting at 50 mg and adjustable to 100 mg before sexual activity for 6 weeks.
 MAIN OUTCOME MEASURES The primary outcome measure was score on the Clinical Global Impression-Sexual Function (CGI-SF); secondary measures were scores on the International Index of Erectile Function, Arizona Sexual Experience Scale, Massachusetts General Hospital-Sexual Functioning Questionnaire, and Hamilton Rating Scale for Depression (HAM-D).
 RESULTS Among the 90 randomized patients, 93% (83/89) of patients treated per protocol took at least 1 dose of study drug and 85% (76/89) completed week 6 end-point assessments with last observation carried forward analyses. At a CGI-SF score of 2 or lower, 54.5% (24/44) of sildenafil compared with 4.4% (2/45) of placebo patients were much or very much improved (P<.001). Erectile function, arousal, ejaculation, orgasm, and overall satisfaction domain measures improved significantly in sildenafil compared with placebo patients. Mean depression scores remained consistent with remission (HAM-D score < or =10) in both groups for the study duration.
 CONCLUSION In our study, sildenafil effectively improved erectile function and other aspects of sexual function in men with sexual dysfunction associated with the use of SRI antidepressants. These improvements may allow patients to maintain adherence with effective antidepressant treatment.

title: Misunderstandings in prescribing decisions in general practice: qualitative study.

text:
OBJECTIVES To identify and describe misunderstandings between patients and doctors associated with prescribing decisions in general practice.
 DESIGN Qualitative study.
 SETTING 20 general practices in the West Midlands and south east England.
 PARTICIPANTS 20 general practitioners and 35 consulting patients.
 MAIN OUTCOME MEASURES Misunderstandings between patients and doctors that have potential or actual adverse consequences for taking medicine.
 RESULTS 14 categories of misunderstanding were identified relating to patient information unknown to the doctor, doctor information unknown to the patient, conflicting information, disagreement about attribution of side effects, failure of communication about doctor's decision, and relationship factors. All the misunderstandings were associated with lack of patients' participation in the consultation in terms of the voicing of expectations and preferences or the voicing of responses to doctors' decisions and actions. They were all associated with potential or actual adverse outcomes such as non-adherence to treatment. Many were based on inaccurate guesses and assumptions. In particular doctors seemed unaware of the relevance of patients' ideas about medicines for successful prescribing.
 CONCLUSIONS Patients' participation in the consultation and the adverse consequences of lack of participation are important. The authors are developing an educational intervention that builds on these findings.

title: Bezafibrate in men with lower extremity arterial disease: randomised controlled trial.

text:
OBJECTIVE To assess the effect of bezafibrate on the risk of coronary heart disease and stroke in men with lower extremity arterial disease.
 DESIGN Double blind placebo controlled randomised trial.
 SETTING 85 general practices and nine hospital vascular clinics.
 PARTICIPANTS 1568 men, mean age 68.2 years (range 35 to 92) at recruitment.
 INTERVENTIONS Bezafibrate 400 mg daily (783 men) or placebo (785 men).
 MAIN OUTCOME MEASURES Combination of coronary heart disease and of stroke. All coronary events, fatal and non-fatal coronary events separately, and strokes alone (secondary end points).
 RESULTS Bezafibrate did not reduce the incidence of coronary heart disease and stroke. There were 150 and 160 events in the active and placebo groups respectively (relative risk 0.96, 95% confidence interval 0.76 to 1.21). There were 90 and 111 major coronary events in the active and placebo groups respectively (0.81, 0.60 to 1.08), of which 64 and 65 were fatal (0.95, 0.66 to 1.37) and 26 and 46 non-fatal (0.60, 0.36 to 0.99). Beneficial effects on non-fatal events were greatest in men aged <65 years at entry, in whom benefit was also seen for all coronary events (0.38, 0.20 to 0.72). There were no significant effects in older men. There were 60 strokes in those on active treatment and 49 in those on placebo (1.34, 0.80 to 2.01). There were 204 and 195 deaths from all causes in the two groups respectively (1.03, 0.83 to 1.26). Bezafibrate reduced the severity of intermittent claudication for up to three years.
 CONCLUSIONS Bezafibrate has no effect on the incidence of coronary heart disease and of stroke combined but may reduce the incidence of non-fatal coronary events, particularly in those aged <65 years at entry, in whom all coronary events may also be reduced.

title: In-hospital switching of oral P2Y12 inhibitor treatment in patients with acute coronary syndrome undergoing percutaneous coronary intervention: prevalence, predictors and short-term outcome.

text:
BACKGROUND P2Y12 inhibitor switching has appeared in clinical practice as a consequence of prasugrel and ticagrelor availability, apart from clopidogrel, for use in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI).
 METHODS In the context of the GReek AntiPlatelet REgistry (GRAPE) we assessed the prevalence, predictive factors and short-term outcome of in-hospital P2Y12 inhibitor switching in 1794 ACS patients undergoing PCI.
 RESULTS Switching occurred in 636 (35.5%) patients of which in the form of clopidogrel to a novel agent, novel agent to clopidogrel and between prasugrel and ticagrelor in 574 (90.4%), 34 (5.3%) and 27 (4.3%) patients, respectively. Presentation to non PCI-capable hospital, bivalirudin use, age ≥75 years (inverse predictor), and regional trends emerged as predictive factors of switching to a novel agent. At combined in-hospital and one-month follow-up, propensity matched pairs analysis showed no differences in major adverse cardiovascular (MACE) or bleeding events between switching from clopidogrel to a novel agent vs novel agent constant administration. More Bleeding Academic Research Consortium type 1, type 2 and any type events and fewer MACE were seen when switching from clopidogrel to a novel agent vs only clopidogrel administration (23.7%, 3.8%, 30.6%, 1.2% vs 8.9%, 1.2%, 12.0%, 3.8% with P < .001, P = .03, P < .001 and P = .03 respectively).
 CONCLUSIONS In a real-life experience with contemporary antiplatelet treatment in ACS patients undergoing PCI, in-hospital switching represents common clinical practice. Clinical factors and regional practice differences seem to affect this strategy's choice, while switching to a novel agent may be associated with higher risk of bleeding.

title: Venous thrombosis in cancer patients: insights from the FRONTLINE survey.

text:
BACKGROUND Venous thromboembolism (VTE) is a common complication in cancer patients and a significant cause of morbidity and mortality. However, little information is available on oncologists' perceptions of the risk of VTE and its management. The Fundamental Research in Oncology and Thrombosis (FRONTLINE) study is the first comprehensive global survey of thrombosis and cancer. The study was designed to collect data on the perceived risk and patterns of practice with regard to VTE in cancer patients undergoing surgical and medical management of their malignancy and to provide information on international and regional practice patterns, allowing for the design of research studies to answer the concerns of practicing clinicians.
 METHODS Literature reviews were performed to provide a current evidence base against which to compare the findings, and a survey was developed under the guidance of an advisory board. A paper-based reply-paid questionnaire was distributed globally between July and November 2001 to clinicians involved in cancer care and was made available on a dedicated website.
 FINDINGS A total of 3,891 completed responses were available for analysis. Brain and pancreatic tumors were considered to carry a high risk for VTE, and 80% of respondents considered the use of central venous lines to be associated with a high risk of VTE. Marked differences were seen in the use of thromboprophylaxis for surgical and medical cancer patients, with over 50% of surgeons reporting that they initiated thromboprophylaxis routinely, while most medical oncologists reported using thromboprophylaxis in less than 5% of medical patients. Low molecular weight heparin (LMWH) was the most popular method of thromboprophylaxis employed in both surgical and medical patients and was more favored by European than U.S. clinicians. Some 20% of respondents reported using aspirin for prophylaxis, despite there being no reliable evidence for this agent as effective in prevention in this population. For the treatment of VTE, LMWH was again the most common initial treatment, although, for the long-term, oral anticoagulation therapy was widely adopted. Many patients were treated for VTE on an outpatient basis, and secondary prevention of VTE was typically continued for 3 to 6 months after an episode of deep vein thrombosis or for longer in the case of pulmonary embolism.
 INTERPRETATION The results of the FRONTLINE survey demonstrate a need for guidelines to direct clinical practice in line with evidence-based data concerning cancer and VTE. Oncologists need to be educated regarding the true risks of VTE associated with certain cancers and on strategies for prevention and treatment to reduce the morbidity and mortality associated with VTE in all cancer patients. The study has also helped identify areas for future research.

title: Cost-effectiveness of options for the diagnosis of high blood pressure in primary care: a modelling study.

text:
BACKGROUND The diagnosis of hypertension has traditionally been based on blood-pressure measurements in the clinic, but home and ambulatory measurements better correlate with cardiovascular outcome, and ambulatory monitoring is more accurate than both clinic and home monitoring in diagnosing hypertension. We aimed to compare the cost-effectiveness of different diagnostic strategies for hypertension.
 METHODS We did a Markov model-based probabilistic cost-effectiveness analysis. We used a hypothetical primary-care population aged 40 years or older with a screening blood-pressure measurement greater than 140/90 mm Hg and risk-factor prevalence equivalent to the general population. We compared three diagnostic strategies-further blood pressure measurement in the clinic, at home, and with an ambulatory monitor-in terms of lifetime costs, quality-adjusted life years, and cost-effectiveness.
 FINDINGS Ambulatory monitoring was the most cost-effective strategy for the diagnosis of hypertension for men and women of all ages. It was cost-saving for all groups (from -£56 [95% CI -105 to -10] in men aged 75 years to -£323 [-389 to -222] in women aged 40 years) and resulted in more quality-adjusted life years for men and women older than 50 years (from 0·006 [0·000 to 0·015] for women aged 60 years to 0·022 [0·012 to 0·035] for men aged 70 years). This finding was robust when assessed with a wide range of deterministic sensitivity analyses around the base case, but was sensitive if home monitoring was judged to have equal test performance to ambulatory monitoring or if treatment was judged effective irrespective of whether an individual was hypertensive.
 INTERPRETATION Ambulatory monitoring as a diagnostic strategy for hypertension after an initial raised reading in the clinic would reduce misdiagnosis and save costs. Additional costs from ambulatory monitoring are counterbalanced by cost savings from better targeted treatment. Ambulatory monitoring is recommended for most patients before the start of antihypertensive drugs.
 FUNDING National Institute for Health Research and the National Institute for Health and Clinical Excellence.