Publications by authors named "Wit H"

Here, we extended our findings from a genome-wide association study of the euphoric response to d-amphetamine in healthy human volunteers by identifying enrichment between SNPs associated with response to d-amphetamine and SNPs associated with psychiatric disorders. We found that SNPs nominally associated (P ≤ 0.05 and P ≤ 0.

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  • The text outlines a new technique for preparing ultrathin cell or tissue sections that can be used for both fluorescence and electron microscopy, improving on the original Tokuyasu method.
  • The process involves stabilizing immuno-labelled sections in a thin layer of vitreous water by plunge-freezing, allowing for enhanced imaging at cryogenic temperatures.
  • This innovative method, referred to as VOS (vitrification of sections), is particularly effective for studying cellular structures in three dimensions, making it a valuable tool for Correlative Light and Electron Microscopy (CLEM) with applications in observing lysosomes and synapses in cells like dendritic cells and neurons.
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Abused drugs can profoundly alter mental states in ways that may motivate drug use. These effects are usually assessed with self-report, an approach that is vulnerable to biases. Analyzing speech during intoxication may present a more direct, objective measure, offering a unique 'window' into the mind.

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3,4-Methylenedioxymethamphetamine (MDMA, 'ecstasy') is used recreationally to improve mood and sociability, and has generated clinical interest as a possible adjunct to psychotherapy. One way that MDMA may produce positive 'prosocial' effects is by changing responses to emotional stimuli, especially stimuli with social content. Here, we examined for the first time how MDMA affects subjective responses to positive, negative and neutral emotional pictures with and without social content.

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Rationale: Several laboratories have conducted placebo-controlled drug challenge studies with 3,4-methylenedioxymethamphetamine (MDMA), providing a unique source of data to examine the reliability of the acute effects of the drug across subject samples and settings. We examined the subjective and physiological responses to the drug across three different laboratories and investigated the influence of prior MDMA use.

Methods: Overall, 220 healthy volunteers with varying levels of previous MDMA experience participated in laboratory-based studies in which they received placebo or MDMA orally (1.

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In this Special Section, the relationships among attention deficit hyperactivity disorder (ADHD), impulsivity, and alcohol abuse are explored by 4 diverse studies. Among these excellent studies, the constructs indicated in the issue title varied in definitions, measurement methods, and interpretive implications. The experimental approaches also varied, including cross-sectional examination of candidate genes in children, determination of long-term outcomes, laboratory tasks to measure attention and inhibition, and alcohol administration.

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Stimulant drugs facilitate both encoding and retrieval of salient information in laboratory animals, but less is known about their effects on memory for emotionally salient visual images in humans. The current study investigated dextroamphetamine (AMP) effects on memory for emotional pictures in healthy humans, by administering the drug only at encoding, only at retrieval, or at both encoding and retrieval. During the encoding session, all participants viewed standardized positive, neutral, and negative pictures from the International Affective Picture System (IAPS).

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Environmental drivers of total mercury (TotHg) concentrations, methylmercury (MeHg) concentrations, and MeHg fractions (a proxy for methylation potential, expressed as %MeHg) were assessed in a synoptic study of 51 lakes in southeast (Boreal) and northeast (Subarctic) Norway. Concentrations of TotHg and MeHg ranged between 0.5-6.

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MDMA (± 3,4-methylenedioxymethamphetamine, 'ecstasy') is used recreationally, reportedly because it increases feelings of empathy, sociability, and interpersonal closeness. One line of evidence suggests that MDMA produces these effects by releasing oxytocin, a peptide involved in social bonding. In the current study, we investigated the acute effects of MDMA and oxytocin on social and emotional processing in healthy human volunteers.

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Expanding high-elevation and high-latitude forest has contrasting climate feedbacks through carbon sequestration (cooling) and reduced surface reflectance (warming), which are yet poorly quantified. Here, we present an empirically based projection of mountain birch forest expansion in south-central Norway under climate change and absence of land use. Climate effects of carbon sequestration and albedo change are compared using four emission metrics.

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3-4-Methylenedioxymethamphetamine (MDMA) increases self-reported positive social feelings and decreases the ability to detect social threat in faces, but its effects on experiences of social acceptance and rejection have not been determined. We examined how an acute dose of MDMA affects subjective and autonomic responses to simulated social acceptance and rejection. We predicted that MDMA would decrease subjective responses to rejection.

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Here, we review the evidence for sex differences in behavioral measures of impulsivity for both humans and laboratory animals. We focus on two specific components of impulsivity: impulsive action (i.e.

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Moderate doses of stimulant drugs are known to enhance memory encoding and consolidation, but their effects on memory retrieval have not been explored in depth. In laboratory animals, stimulants seem to improve retrieval of emotional memories, but comparable studies have not been carried out in humans. In the present study, we examined the effects of dextroamphetamine (AMP) on retrieval of emotional and unemotional stimuli in healthy young adults, using doses that enhanced memory formation when administered before encoding in our previous study.

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  • Synaptotagmin-1 and -7 are primary calcium sensors for exocytosis in mouse chromaffin cells, while the function of the calcium-binding protein Doc2b is less clear.
  • Research using Doc2b knock-out mice indicates that Doc2b is not essential for calcium-triggered vesicle priming and release but influences the distribution of vesicle release.
  • Overexpression of Doc2b inhibits sustained release and increases the readily releasable pool, suggesting that Doc2b regulates the timing of vesicle fusion during high calcium levels to prevent premature release.
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Behavioral measures of impulsivity are widely used in substance abuse research, yet relatively little attention has been devoted to establishing their psychometric properties, especially their reliability over repeated administration. The current study examined the test-retest reliability of a battery of standardized behavioral impulsivity tasks, including measures of impulsive choice (i.e.

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  • - The assembly of the SNARE complex, essential for exocytosis, is influenced by the calcium-dependent interactions with synaptotagmin-1, particularly at two newly identified sites on SNAP-25.
  • - Research using high-resolution electrophysiological techniques shows that one key synaptotagmin-1 binding site on SNAP-25 is crucial for vesicle docking, priming, and fast neurotransmitter release, while the other binding site has a less significant role.
  • - Additionally, differences in synaptotagmin-1 interactions with two SNAP-25 isoforms (SNAP-25A and SNAP-25B) reveal that these interactions are vital for vesicle release control and vary across developmental stages.
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The frail elderly populations of nursing homes frequently use drugs and suffer from considerable comorbidities. Medication reviews are intended to support evidence based prescribing and optimise therapy. However, literature is still ambiguous regarding the optimal method and the effects of medication reviews.

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Background: Both impulsivity and sensitivity to the rewarding effects of drugs have long been considered risk factors for drug abuse. There is some preclinical evidence to suggest that the two are related; however, there is little information about how specific behavioral components of impulsivity are related to the acute euphorigenic effects of drugs in humans. The aim of the current study was to examine the degree to which both inattention and impulsive action predicted subjective response to amphetamine.

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The presynaptic active zone mediates synaptic vesicle exocytosis, and modulation of its molecular composition is important for many types of synaptic plasticity. Here, we identify synaptic scaffold protein liprin-α2 as a key organizer in this process. We show that liprin-α2 levels were regulated by synaptic activity and the ubiquitin-proteasome system.

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Caffeinated alcoholic beverage (CAB) consumption is a rapidly growing phenomenon among young adults and is associated with a variety of health-risk behaviors. The current study examined whether either caffeinated alcohol or the expectation of receiving caffeinated alcohol altered affective, cognitive, and behavioral outcomes hypothesized to contribute to risk behavior. Young adult social drinkers (N = 146) participated in a single session where they received alcohol (peak Breath Alcohol Content = .

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Rationale: Alcohol is usually consumed in social contexts. However, the drug has been studied mainly under socially isolated conditions, and our understanding of how social setting affects response to alcohol is limited.

Objectives: The current study compared the subjective, physiological, and behavioral effects of a moderate dose of alcohol in moderate social drinkers who were tested in either a social or an isolated context and in the presence of others who had or had not consumed alcohol.

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Stimuli, including contexts, which predict the availability or onset of a drug effect, can acquire conditioned incentive motivational properties. These conditioned properties endure after withdrawal, and can promote drug-seeking which may result in relapse. Conditioned place preference (CPP) assesses the associations between drugs and the context in which they are experienced.

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