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1,672 result(s) for "Harris, Julia"
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Fast odour dynamics are encoded in the olfactory system and guide behaviour
Odours are transported in turbulent plumes, which result in rapid concentration fluctuations 1 , 2 that contain rich information about the olfactory scenery, such as the composition and location of an odour source 2 – 4 . However, it is unclear whether the mammalian olfactory system can use the underlying temporal structure to extract information about the environment. Here we show that ten-millisecond odour pulse patterns produce distinct responses in olfactory receptor neurons. In operant conditioning experiments, mice discriminated temporal correlations of rapidly fluctuating odours at frequencies of up to 40 Hz. In imaging and electrophysiological recordings, such correlation information could be readily extracted from the activity of mitral and tufted cells—the output neurons of the olfactory bulb. Furthermore, temporal correlation of odour concentrations 5 reliably predicted whether odorants emerged from the same or different sources in naturalistic environments with complex airflow. Experiments in which mice were trained on such tasks and probed using synthetic correlated stimuli at different frequencies suggest that mice can use the temporal structure of odours to extract information about space. Thus, the mammalian olfactory system has access to unexpectedly fast temporal features in odour stimuli. This endows animals with the capacity to overcome key behavioural challenges such as odour source separation 5 , figure–ground segregation 6 and odour localization 7 by extracting information about space from temporal odour dynamics. Fast temporal dynamics of the olfactory environment can be perceived by mice and used to perform scene segmentation.
Initial combination therapy with ambrisentan and tadalafil in connective tissue disease-associated pulmonary arterial hypertension (CTD-PAH): subgroup analysis from the AMBITION trial
BackgroundPatients with connective tissue disease-associated pulmonary arterial hypertension (CTD-PAH), in particular systemic sclerosis (SSc), had an attenuated response compared with idiopathic PAH in most trials. Thus, there is uncertainty regarding the benefit of PAH-targeted therapy in some forms of CTD-PAH.ObjectiveTo explore the safety and efficacy of initial combination therapy with ambrisentan and tadalafil versus ambrisentan or tadalafil monotherapy in patients with CTD-PAH and SSc-PAH enrolled in the AMBITION trial.MethodsThis was a post hoc analysis of patients with CTD-PAH and SSc-PAH from AMBITION, an event-driven, double-blind trial in patients with WHO functional class II/III PAH. Treatment-naive patients were randomised 2:1:1 to once-daily initial combination therapy with ambrisentan plus tadalafil or monotherapy with ambrisentan or tadalafil, respectively. The primary endpoint was time to the first clinical failure event (first occurrence of death, hospitalisation for worsening PAH, disease progression or unsatisfactory long-term clinical response).ResultsIn the primary analysis set (N=500), 187 patients had CTD-PAH, of whom 118 had SSc-PAH. Initial combination therapy reduced the risk of clinical failure versus pooled monotherapy in each subgroup: CTD-PAH (HR 0.43 (95% CI 0.24 to 0.77)) and SSc-PAH (0.44 (0.22 to 0.89)). The most common AE was peripheral oedema, which was reported more frequently with initial combination therapy than monotherapy in the two PAH subgroups. The relative frequency of adverse events between those on combination therapy versus monotherapy was similar across subgroups.ConclusionsThis post hoc subgroup analysis provides evidence that CTD-PAH and SSc-PAH patients benefit from initial ambrisentan and tadalafil combination therapy.Trial registration number NCT01178073, post results.
GABA and glutamate neurons in the VTA regulate sleep and wakefulness
Yu, Li et al. show that VTA GABA and glutamate neurons induce sleep and waking, respectively, via projections to the lateral hypothalamus and nucleus accumbens. Thus, in addition to influencing reward-directed behaviors, the VTA regulates arousal.
Blood Biomarkers of Alcohol Use: A Scoping Review
Purpose of Review Understanding whether a person has consumed alcohol or not, as well as quantitative assessment of alcohol use, are often based on self-reported measures, which may be subject to recall bias, among other challenges. Although not without limitations, blood biomarkers may complement self-reported assessments to provide a more accurate determination of the presence and quantity of alcohol use. The aim of this review is to provide a critical overview of the current knowledge and research on biomarkers of alcohol use, with a particular focus on blood tests. Recent Findings This scoping review summarizes the published work on blood tests currently used in clinical practice, including phosphatidyl ethanol (PEth), fatty acid ethyl ester (FAEE), carbohydrate-deficient transferrin (CDT), total serum sialic acid (TSA), mean corpuscular volume (MCV), alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma glutamyl transpeptidase (GGT), and cholesteryl ester transfer protein (CETP). Emerging blood biomarkers with a potential use to assess alcohol drinking are also briefly reviewed, including N-Acetyl-β-Hexosaminidase (Beta-Hex), macrophage migration inhibitory factor (MIF), and d -dopachrome tautomerase (DDT). We discuss the aforementioned biomarkers in the context of their clinical implications, characteristics, strengths, and limitations. Summary The available blood biomarkers considerably vary in the time period in which they detect alcohol use and the amount of alcohol they are sensitive to. While currently available biomarkers provide useful information, especially in combination with self-reported measures, future work is needed to identify more sensitive and specific blood biomarkers for different levels and patterns of alcohol use. Integration of such biomarkers into clinical practice and research will increase the accuracy and richness of the data and may guide more effective and targeted strategies for prevention, diagnosis, and treatment of excessive alcohol use.
Metabolic differentiation in the embryonic retina
It is unclear whether proliferating and differentiating cells produce energy through different metabolic pathways. Harris and colleagues show, in the embryonic Xenopus retina, that dividing progenitors use glycogen for glycolysis, and that a transition to oxidative phosphorylation occurs as cells differentiate. Unlike healthy adult tissues, cancers produce energy mainly by aerobic glycolysis instead of oxidative phosphorylation 1 . This adaptation, called the Warburg effect, may be a feature of all dividing cells, both normal and cancerous 2 , or it may be specific to cancers 3 . It is not known whether, in a normally growing tissue during development, proliferating and postmitotic cells produce energy in fundamentally different ways. Here we show in the embryonic Xenopus retina in vivo , that dividing progenitor cells depend less on oxidative phosphorylation for ATP production than non-dividing differentiated cells, and instead use glycogen to fuel aerobic glycolysis. The transition from glycolysis to oxidative phosphorylation is connected to the cell differentiation process. Glycolysis is indispensable for progenitor proliferation and biosynthesis, even when it is not used for ATP production. These results suggest that the Warburg effect can be a feature of normal proliferation in vivo , and that the regulation of glycolysis and oxidative phosphorylation is critical for normal development.
Energy-efficient information transfer at thalamocortical synapses
We have previously shown that the physiological size of postsynaptic currents maximises energy efficiency rather than information transfer across the retinothalamic relay synapse. Here, we investigate information transmission and postsynaptic energy use at the next synapse along the visual pathway: from relay neurons in the thalamus to spiny stellate cells in layer 4 of the primary visual cortex (L4SS). Using both multicompartment Hodgkin-Huxley-type simulations and electrophysiological recordings in rodent brain slices, we find that increasing or decreasing the postsynaptic conductance of the set of thalamocortical inputs to one L4SS cell decreases the energy efficiency of information transmission from a single thalamocortical input. This result is obtained in the presence of random background input to the L4SS cell from excitatory and inhibitory corticocortical connections, which were simulated (both excitatory and inhibitory) or injected experimentally using dynamic-clamp (excitatory only). Thus, energy efficiency is not a unique property of strong relay synapses: even at the relatively weak thalamocortical synapse, each of which contributes minimally to the output firing of the L4SS cell, evolutionarily-selected postsynaptic properties appear to maximise the information transmitted per energy used.
Initial Use of Ambrisentan plus Tadalafil in Pulmonary Arterial Hypertension
Patients with previously untreated pulmonary arterial hypertension who were randomly assigned to combination therapy with ambrisentan and tadalafil had a significantly lower risk of a composite clinical failure outcome at 20 months than did the pooled monotherapy group. Regardless of the initiating trigger, pulmonary arterial hypertension results in the altered synthesis of a variety of vasoactive substances derived from the endothelium. 1 Current therapies for pulmonary arterial hypertension 2 target abnormalities in one of three intracellular pathways with signaling dysfunction: the prostacyclin, nitric oxide, or endothelin pathway. 1 However, no single class of drug is consistently effective in treating all patients, which suggests that no single pathway plays a dominant pathogenic role. 3 , 4 Combination therapy with agents that target several different pathways may potentially increase the overall therapeutic effect on the mechanisms of this disease 5 and provide additional clinical benefits. 6 – . . .
The Structure of Suicidal Beliefs: A Bifactor Analysis of the Suicide Cognitions Scale
The Suicide Cognitions Scale (SCS) was developed to measure a broad spectrum of suicidogenic cognitions collectively referred to as the suicidal belief system. Prior confirmatory factor analyses have suggested both a unidimensional and multidimensional structure and high intercorrelations among identified factors, suggesting the possible influence of an underlying general factor. The present study used bifactor analysis in a clinical sample of 97 treatment-seeking Army personnel with recent suicide ideation and a nonclinical sample of 193 military personnel and veterans with a lifetime history of suicide ideation or attempts. Results supported the strong influence of a general factor in addition to several specific factors that aligned with constructs articulated by several theories of suicide, and suggested the SCS is best interpreted as a unidimensional measure. Results suggest that narrower suicidogenic cognitions are influenced in large part by a strong general latent variable.
Once-daily dolutegravir versus darunavir plus ritonavir in antiretroviral-naive adults with HIV-1 infection (FLAMINGO): 48 week results from the randomised open-label phase 3b study
Dolutegravir has been shown to be non-inferior to an integrase inhibitor and superior to a non-nucleoside reverse transcriptase inhibitor (NNRTI). In FLAMINGO, we compared dolutegravir with darunavir plus ritonavir in individuals naive for antiretroviral therapy. In this multicentre, open-label, phase 3b, non-inferiority study, HIV-1-infected antiretroviral therapy-naive adults with HIV-1 RNA concentration of 1000 copies per mL or more and no resistance at screening were randomly assigned (1:1) to receive either dolutegravir 50 mg once daily or darunavir 800 mg plus ritonavir 100 mg once daily, with investigator-selected tenofovir–emtricitabine or abacavir–lamivudine. Randomisation was stratified by screening HIV-1 RNA (≤100 000 or >100 000 copies per mL) and nucleoside reverse transcriptase inhibitor (NRTI) selection. The primary endpoint was the proportion of patients with HIV-1 RNA concentration lower than 50 copies per mL (Food and Drug Administration [FDA] snapshot algorithm) at week 48 with a 12% non-inferiority margin. This trial is registered with ClinicalTrials.gov, NCT01449929. Recruitment began on Oct 31, 2011, and was completed on May 24, 2012, in 64 research centres in nine countries worldwide. Of 595 patients screened, 484 patients were included in the analysis (242 in each group). At week 48, 217 (90%) patients receiving dolutegravir and 200 (83%) patients receiving darunavir plus ritonavir had HIV-1 RNA of less than 50 copies per mL (adjusted difference 7·1%, 95% CI 0·9–13·2), non-inferiority and on pre-specified secondary analysis dolutegravir was superior (p=0·025). Confirmed virological failure occurred in two (<1%) patients in each group; we recorded no treatment-emergent resistance in either group. Discontinuation due to adverse events or stopping criteria was less frequent for dolutegravir (four [2%] patients) than for darunavir plus ritonavir (ten [4%] patients) and contributed to the difference in response rates. The most commonly reported (≥10%) adverse events were diarrhoea (dolutegravir 41 [17%] patients vs darunavir plus ritonavir 70 [29%] patients), nausea (39 [16%] vs 43 [18%]), and headache (37 [15%] vs 24 [10%]). Patients receiving dolutegravir had significantly fewer low-density lipoprotein values of grade 2 or higher (11 [2%] vs 36 [7%]; p=0·0001). Once-daily dolutegravir was superior to once-daily darunavir plus ritonavir. Once-daily dolutegravir in combination with fixed-dose NRTIs represents an effective new treatment option for HIV-1-infected, treatment-naive patients. ViiV Healthcare and Shionogi & Co.
Autism and Sensory Processing Disorders: Shared White Matter Disruption in Sensory Pathways but Divergent Connectivity in Social-Emotional Pathways
Over 90% of children with Autism Spectrum Disorders (ASD) demonstrate atypical sensory behaviors. In fact, hyper- or hyporeactivity to sensory input or unusual interest in sensory aspects of the environment is now included in the DSM-5 diagnostic criteria. However, there are children with sensory processing differences who do not meet an ASD diagnosis but do show atypical sensory behaviors to the same or greater degree as ASD children. We previously demonstrated that children with Sensory Processing Disorders (SPD) have impaired white matter microstructure, and that this white matter microstructural pathology correlates with atypical sensory behavior. In this study, we use diffusion tensor imaging (DTI) fiber tractography to evaluate the structural connectivity of specific white matter tracts in boys with ASD (n = 15) and boys with SPD (n = 16), relative to typically developing children (n = 23). We define white matter tracts using probabilistic streamline tractography and assess the strength of tract connectivity using mean fractional anisotropy. Both the SPD and ASD cohorts demonstrate decreased connectivity relative to controls in parieto-occipital tracts involved in sensory perception and multisensory integration. However, the ASD group alone shows impaired connectivity, relative to controls, in temporal tracts thought to subserve social-emotional processing. In addition to these group difference analyses, we take a dimensional approach to assessing the relationship between white matter connectivity and participant function. These correlational analyses reveal significant associations of white matter connectivity with auditory processing, working memory, social skills, and inattention across our three study groups. These findings help elucidate the roles of specific neural circuits in neurodevelopmental disorders, and begin to explore the dimensional relationship between critical cognitive functions and structural connectivity across affected and unaffected children.