330 research outputs found

    Chemical and metallurgical analyses of 6Al-4V titanium test specimens exposed to hydrazine /N2H2/ liquid propellant

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    Chemical and metallurgical analyses of 6Al-4V titanium test specimens exposed to hydrazine /N2H2/ liquid propellan

    Alterations of consciousness and mystical-type experiences after acute LSD in humans

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    Lysergic acid diethylamide (LSD) is used recreationally and in clinical research. Acute mystical-type experiences that are acutely induced by hallucinogens are thought to contribute to their potential therapeutic effects. However, no data have been reported on LSD-induced mystical experiences and their relationship to alterations of consciousness. Additionally, LSD dose- and concentration-response functions with regard to alterations of consciousness are lacking.; We conducted two placebo-controlled, double-blind, cross-over studies using oral administration of 100 and 200 μg LSD in 24 and 16 subjects, respectively. Acute effects of LSD were assessed using the 5 Dimensions of Altered States of Consciousness (5D-ASC) scale after both doses and the Mystical Experience Questionnaire (MEQ) after 200 μg.; On the MEQ, 200 μg LSD induced mystical experiences that were comparable to those in patients who underwent LSD-assisted psychotherapy but were fewer than those reported for psilocybin in healthy subjects or patients. On the 5D-ASC scale, LSD produced higher ratings of blissful state, insightfulness, and changed meaning of percepts after 200 μg compared with 100 μg. Plasma levels of LSD were not positively correlated with its effects, with the exception of ego dissolution at 100 μg.; Mystical-type experiences were infrequent after LSD, possibly because of the set and setting used in the present study. LSD may produce greater or different alterations of consciousness at 200 μg (i.e., a dose that is currently used in psychotherapy in Switzerland) compared with 100 μg (i.e., a dose used in imaging studies). Ego dissolution may reflect plasma levels of LSD, whereas more robustly induced effects of LSD may not result in such associations

    Multifaceted empathy of healthy volunteers after single doses of MDMA: A pooled sample of placebo-controlled studies

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    Previous placebo-controlled experimental studies have shown that a single dose of MDMA can increase emotional empathy in the multifaceted empathy test (MET) without affecting cognitive empathy. Although sufficiently powered to detect main effects of MDMA, these studies were generally underpowered to also validly assess contributions of additional parameters, such as sex, drug use history, trait empathy and MDMA or oxytocin plasma concentrations. The present study examined the robustness of the MDMA effect on empathy and investigated the moderating role of these additional parameters. Participants ( n = 118) from six placebo-controlled within-subject studies and two laboratories were included in the present pooled analysis. Empathy (MET), MDMA and oxytocin plasma concentrations were assessed after oral administration of MDMA (single dose, 75 or 125 mg). Trait empathy was assessed using the interpersonal reactivity index. We confirmed that MDMA increased emotional empathy at both doses without affecting cognitive empathy. This MDMA-related increase in empathy was most pronounced during presentation of positive emotions as compared with negative emotions. MDMA-induced empathy enhancement was positively related to MDMA blood concentrations measured before the test, but independent of sex, drug use history and trait empathy. Oxytocin concentrations increased after MDMA administration but were not associated with behavioral effects. The MDMA effects on emotional empathy were stable across laboratories and doses. Sex did not play a moderating role in this effect, and oxytocin levels, trait empathy and drug use history were also unrelated. Acute drug exposure was of significant relevance in the MDMA-induced emotional empathy elevation

    Alcohol acutely enhances decoding of positive emotions and emotional concern for positive stimuli and facilitates the viewing of sexual images

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    Social cognition influences social interactions. Alcohol reportedly facilitates social interactions. However, the acute effects of alcohol on social cognition are relatively poorly studied.; We investigated the effects of alcoholic or non-alcoholic beer on emotion recognition, empathy, and sexual arousal using the dynamic face emotion recognition task (FERT), Multifaceted Empathy Test (MET), and Sexual Arousal Task (SAT) in a double-blind, random-order, cross-over study in 60 healthy social drinkers. We also assessed subjective effects using visual analog scales (VASs), blood alcohol concentrations, and plasma oxytocin levels.; Alcohol increased VAS ratings of stimulated, happy, talkative, open, and want to be with others. The subjective effects of alcohol were greater in participants with higher trait inhibitedness. Alcohol facilitated the recognition of happy faces on the FERT and enhanced emotional empathy for positive stimuli on the MET, particularly in participants with low trait empathy. Pictures of explicit sexual content were rated as less pleasant than neutral pictures after non-alcoholic beer but not after alcoholic beer. Explicit sexual pictures were rated as more pleasant after alcoholic beer compared with non-alcoholic beer, particularly in women. Alcohol did not alter the levels of circulating oxytocin.; Alcohol biased emotion recognition toward better decoding of positive emotions and increased emotional concern for positive stimuli. No support was found for a modulatory role of oxytocin. Alcohol also facilitated the viewing of sexual images, consistent with disinhibition, but it did not actually enhance sexual arousal. These effects of alcohol on social cognition likely enhance sociability.; www.clinicaltrials.gov/ct2/show/NCT02318823

    Comparative Effects of Methylphenidate, Modafinil, and MDMA on Response Inhibition Neural Networks in Healthy Subjects

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    Psychostimulants such as methylphenidate and modafinil are increasingly used by healthy people for cognitive enhancement purposes, whereas the acute effect of 3,4-methylenedioxymethamphetamine (ecstasy) on cognitive functioning in healthy subjects remains unclear. This study directly compared the acute effects of methylphenidate, modafinil, and 3,4-methylenedioxymethamphetamine on the neural mechanisms underlying response inhibition in healthy subjects.; Using a double-blind, within-subject, placebo-controlled, cross-over design, methylphenidate, modafinil, and 3,4-methylenedioxymethamphetamine were administrated to 21 healthy subjects while performing a go/no-go event-related functional magnetic resonance imaging task to assess brain activation during motor response inhibition.; Relative to placebo, methylphenidate and modafinil but not 3,4-methylenedioxymethamphetamine improved inhibitory performance. Methylphenidate significantly increased activation in the right middle frontal gyrus, middle/superior temporal gyrus, inferior parietal lobule, presupplementary motor area, and anterior cingulate cortex compared with placebo. Methylphenidate also induced significantly higher activation in the anterior cingulate cortex and presupplementary motor area and relative to modafinil. Relative to placebo, modafinil significantly increased activation in the right middle frontal gyrus and superior/inferior parietal lobule, while 3,4-methylenedioxymethamphetamine significantly increased activation in the right middle/inferior frontal gyrus and superior parietal lobule.; Direct comparison of methylphenidate, modafinil, and 3,4-methylenedioxymethamphetamine revealed broad recruitment of fronto-parietal regions but specific effects of methylphenidate on middle/superior temporal gyrus, anterior cingulate cortex, and presupplementary motor area activation, suggesting dissociable modulations of response inhibition networks and potentially the superiority of methylphenidate in the enhancement of cognitive performance in healthy subjects

    Acute effects of LSD on amygdala activity during processing of fearful stimuli in healthy subjects

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    Lysergic acid diethylamide (LSD) induces profound changes in various mental domains, including perception, self-awareness and emotions. We used functional magnetic resonance imaging (fMRI) to investigate the acute effects of LSD on the neural substrate of emotional processing in humans. Using a double-blind, randomised, cross-over study design, placebo or 100 μg LSD were orally administered to 20 healthy subjects before the fMRI scan, taking into account the subjective and pharmacological peak effects of LSD. The plasma levels of LSD were determined immediately before and after the scan. The study (including the a priori-defined study end point) was registered at ClinicalTrials.gov before study start (NCT02308969). The administration of LSD reduced reactivity of the left amygdala and the right medial prefrontal cortex relative to placebo during the presentation of fearful faces (P<0.05, family-wise error). Notably, there was a significant negative correlation between LSD-induced amygdala response to fearful stimuli and the LSD-induced subjective drug effects (P<0.05). These data suggest that acute administration of LSD modulates the engagement of brain regions that mediate emotional processing

    Development and validation of an LC-MS/MS method to quantify lysergic acid diethylamide (LSD), iso-LSD, 2-oxo-3-hydroxy-LSD, and nor-LSD and identify novel metabolites in plasma samples in a controlled clinical trial

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    Lysergic acid diethylamide (LSD) is a widely used recreational drug. The aim of this study was to develop and validate a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the quantification of LSD, iso-LSD, 2-oxo-3-hydroxy LSD (O-H-LSD), and nor-LSD in plasma samples from 24 healthy subjects after controlled administration of 100 μg LSD in a clinical trial. In addition, metabolites that have been recently described in in vitro studies, including lysergic acid monoethylamide (LAE), lysergic acid ethyl-2-hydroxyethylamide (LEO), 2-oxo-LSD, trioxylated-LSD, and 13/14-hydroxy-LSD, should be identified.; Separation of LSD and its metabolites was achieved on a reversed phase chromatography column after turbulent-flow online extraction. For the identification and quantification, a triple-stage quadrupole LC-MS/MS instrument was used.; The validation data showed slight matrix effects for LSD, iso-LSD, O-H-LSD, or nor-LSD. Mean intraday and interday accuracy and precision were 105%/4.81% and 105%/4.35% for LSD, 98.7%/5.75% and 99.4%/7.21% for iso-LSD, 106%/4.54% and 99.4%/7.21% for O-H-LSD, and 107%/5.82% and 102%/5.88% for nor-LSD, respectively. The limit of quantification was 0.05 ng/mL for LSD, iso-LSD, and nor-LSD and 0.1 ng/mL for O-H-LSD. The limit of detection was 0.01 ng/mL for all compounds.; The method described herein was accurate, precise, and the calibration range within the range of expected plasma concentrations. LSD was quantified in the plasma samples of the 24 subjects of the clinical trial, whereas iso-LSD, O-H-LSD, nor-LSD, LAE, LEO, 13/14-hydroxy-LSD, and 2-oxo-LSD could only sporadically be detected but were too low for quantification

    Direct and indirect methods for the quantification of leg volume: Comparison between water displacement volumetry, the disk model method and the frustum sign model method, using the correlation coefficient and the limits of agreement

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    Volume changes can be measured either directly by water-displacement volumetry or by various indirect methods in which calculation of the volume is based on circumference measurements. The aim of the present study was to determine the most appropriate indirect method for lower leg volume calculation using water displacement volumetry as a ‘golden standard’. For 20 male volunteers, age range: 20–35 years, the volume of both lower legs was determined directly by water-displacement volumetry, and indirectly by the frustum sign model method and the disc model method. Calculation of the correlation coefficient and the limits of agreement showed that water-displacement volumetry and the disc model method are interchangeable (r = + 0.99, mean ± 2s = − 45 ± 78 ml), whereas this does not hold for the frustum sign model (r = + 0.93, mean ± 2s = 521 ± 238 ml). In the clinical situation volume measurement can be valuable for monitoring of the severity of oedema or haematoma occurrence after surgery or severe trauma. This non-invasive diagnostic aid may be a valuable adjuvant means of diagnosis for several volume dependent disorders of the extremities

    Presentations due to acute toxicity of psychoactive substances in an urban emergency department in Switzerland: a case series.

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    BACKGROUND Although the recreational use of psychoactive substances is common there is only limited systematic collection of data on acute drug toxicity or hospital presentations, in particular regarding novel psychoactive substances (NPS) that have emerged on the illicit market in the last years. METHODS We included all cases presenting at the emergency department (ED) of the University Hospital of Basel, Switzerland, between October 2014 and September 2015 with acute toxicity due to self-reported recreational drug use or with symptoms/signs consistent with acute toxicity. Intoxications were confirmed using immunoassays and LC-MS/MS, detecting also novel psychoactive substances. RESULTS Among the 50'624 attendances at the ED, 210 were directly related to acute toxicity of recreational drugs. The mean patient age was 33 years and 73 % were male. Analytical drug confirmation was available in 136 cases. Most presentations were reportedly related to cocaine (33 %), cannabis (32 %), and heroin (14 %). The most commonly analytically detected substances were cannabis (33 %), cocaine (27 %), and opioids excluding methadone (19 %). There were only two NPS cases; a severe intoxication with paramethoxymethamphetamine (PMMA) in combination with other substances and an intoxication of minor severity with 2,5-dimethoxy-4-propylphenethylamine (2C-P). The most frequent symptoms were tachycardia (28 %), anxiety (23 %), nausea or vomiting (18 %), and agitation (17 %). Severe complications included two fatalities, two acute myocardial infarctions, seizures (13 cases), and psychosis (six cases). Most patients (76 %) were discharged home, 10 % were admitted to intensive care, and 2 % were referred to psychiatric care. CONCLUSION Most medical problems related to illicit drugs concerned cocaine and cannabis and mainly included sympathomimetic toxicity and/or psychiatric disorders confirming data from the prior year. Importantly, despite the dramatic increase in various NPS being detected in the last years, these substances were infrequently associated with ED presentations compared with classic recreational drugs

    Altered network hub connectivity after acute LSD administration

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    LSD is an ambiguous substance, said to mimic psychosis and to improve mental health in people suffering from anxiety and depression. Little is known about the neuronal correlates of altered states of consciousness induced by this substance. Limited previous studies indicated profound changes in functional connectivity of resting state networks after the administration of LSD. The current investigation attempts to replicate and extend those findings in an independent sample. In a double-blind, randomized, cross-over study, 100 μg LSD and placebo were orally administered to 20 healthy participants. Resting state brain activity was assessed by functional magnetic resonance imaging.; Within; -network and; between; -network connectivity measures of ten established resting state networks were compared between drug conditions. Complementary analysis were conducted using resting state networks as sources in seed-to-voxel analyses. Acute LSD administration significantly decreased functional connectivity; within; visual, sensorimotor and auditory networks and the default mode network. While; between; -network connectivity was widely increased and all investigated networks were affected to some extent, seed-to-voxel analyses consistently indicated increased connectivity between networks and subcortical (thalamus, striatum) and cortical (precuneus, anterior cingulate cortex) hub structures. These latter observations are consistent with findings on the importance of hubs in psychopathological states, especially in psychosis, and could underlay therapeutic effects of hallucinogens as proposed by a recent model
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