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11 result(s) for "Thomann, Jan"
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The Pharmacological Profile of Second Generation Pyrovalerone Cathinones and Related Cathinone Derivative
Pyrovalerone cathinones are potent psychoactive substances that possess a pyrrolidine moiety. Pyrovalerone-type novel psychoactive substances (NPS) are continuously detected but their pharmacology and toxicology are largely unknown. We assessed several pyrovalerone and related cathinone derivatives at the human norepinephrine (NET), dopamine (DAT), and serotonin (SERT) uptake transporters using HEK293 cells overexpressing each respective transporter. We examined the transporter-mediated monoamine efflux in preloaded cells. The receptor binding and activation potency was also assessed at the 5-HT1A, 5-HT2A, 5-HT2B, and 5-HT2C receptors. All pyrovalerone cathinones were potent DAT (IC50 = 0.02–8.7 μM) and NET inhibitors (IC50 = 0.03–4.6 μM), and exhibited no SERT activity at concentrations < 10 μM. None of the compounds induced monoamine efflux. NEH was a potent DAT/NET inhibitor (IC50 = 0.17–0.18 μM). 4F-PBP and NEH exhibited a high selectivity for the DAT (DAT/SERT ratio = 264–356). Extension of the alkyl chain enhanced NET and DAT inhibition potency, while presence of a 3,4-methylenedioxy moiety increased SERT inhibition potency. Most compounds did not exhibit any relevant activity at other monoamine receptors. In conclusion, 4F-PBP and NEH were selective DAT/NET inhibitors indicating that these substances likely produce strong psychostimulant effects and have a high abuse liability.
Acute dose-dependent effects of mescaline in a double-blind placebo-controlled study in healthy subjects
Classic psychedelics have regained interest in research and therapy. Despite the long tradition of the human use of mescaline, modern data on its dose-dependent acute effects and pharmacokinetics are lacking. Additionally, its mechanism of action has not been investigated in humans. We used a randomized, double-blind, placebo-controlled, crossover design in 16 healthy subjects (8 women) who received placebo, mescaline (100, 200, 400, and 800 mg), and 800 mg mescaline together with the serotonin 5-hydroxytryptamine-2A (5-HT 2A ) receptor antagonist ketanserin (40 mg) to assess subjective effects, autonomic effects, adverse effects, and pharmacokinetics up to 30 h after drug administration. Mescaline at doses >100 mg induced dose-dependent acute subjective effects. Mescaline increased systolic and diastolic blood pressure at doses >100 mg, with no difference between doses of 200-800 mg. Heart rate increased dose-dependently. Pharmacokinetics of mescaline were dose-proportional. Maximal concentrations were reached after approximately 2 h, and the plasma elimination half-life was approximately 3.5 h. The average duration of subjective effects increased from 6.4 to 14 h with increasing doses of 100-800 mg mescaline. Nausea and emesis were frequent adverse effects at the 800 mg dose. Co-administration of ketanserin attenuated and shortened acute effects of 800 mg mescaline to become comparable to the 100 and 200 mg doses. There were no ceiling effects of the subjective response within the investigated dose range, but tolerability was lower at the highest doses. These results may assist with dose finding for future research and suggest that acute effects of mescaline are primarily mediated by 5-HT 2A receptors.
In vitro and in vivo metabolism of psilocybin’s active metabolite psilocin
In vivo , psilocybin is rapidly dephosphorylated to psilocin which induces psychedelic effects by interacting with the 5-HT 2A receptor. Psilocin primarily undergoes glucuronidation or conversion to 4-hydroxyindole-3-acetic acid (4-HIAA). Herein, we investigated psilocybin’s metabolic pathways in vitro and in vivo , conducting a thorough analysis of the enzymes involved. Metabolism studies were performed using human liver microsomes (HLM), cytochrome P450 (CYP) enzymes, monoamine oxidase (MAO), and UDP-glucuronosyltransferase (UGT). In vivo , metabolism was examined using male C57BL/6J mice and human plasma samples. Approximately 29% of psilocin was metabolized by HLM, while recombinant CYP2D6 and CYP3A4 enzymes metabolized nearly 100% and 40% of psilocin, respectively. Notably, 4-HIAA and 4-hydroxytryptophol (4-HTP) were detected with HLM but not with recombinant CYPs. MAO-A transformed psilocin into minimal amounts of 4-HIAA and 4-HTP. 4-HTP was only present in vitro . Neither 4-HIAA nor 4-HTP showed relevant interactions at assessed 5-HT receptors. In contrast to in vivo data, UGT1A10 did not extensively metabolize psilocin in vitro . Furthermore, two putative metabolites were observed. N -methyl-4-hydroxytryptamine (norpsilocin) was identified in vitro (CYP2D6) and in mice, while an oxidized metabolite was detected in vitro (CYP2D6) and in humans. However, the CYP2D6 genotype did not influence psilocin plasma concentrations in the investigated study population. In conclusion, MAO-A, CYP2D6, and CYP3A4 are involved in psilocin’s metabolism. The discovery of putative norpsilocin in mice and oxidized psilocin in humans further unravels psilocin’s metabolism. Despite limitations in replicating phase II metabolism in vitro , these findings hold significance for studying drug-drug interactions and advancing research on psilocybin as a therapeutic agent.
Comparative acute effects of mescaline, lysergic acid diethylamide, and psilocybin in a randomized, double-blind, placebo-controlled cross-over study in healthy participants
Mescaline, lysergic acid diethylamide (LSD), and psilocybin are classic serotonergic psychedelics. A valid, direct comparison of the effects of these substances is lacking. The main goal of the present study was to investigate potential pharmacological, physiological and phenomenological differences at psychoactive-equivalent doses of mescaline, LSD, and psilocybin. The present study used a randomized, double-blind, placebo-controlled, cross-over design to compare the acute subjective effects, autonomic effects, and pharmacokinetics of typically used, moderate to high doses of mescaline (300 and 500 mg), LSD (100 µg), and psilocybin (20 mg) in 32 healthy participants. A mescaline dose of 300 mg was used in the first 16 participants and 500 mg was used in the subsequent 16 participants. Acute subjective effects of 500 mg mescaline, LSD, and psilocybin were comparable across various psychometric scales. Autonomic effects of 500 mg mescaline, LSD, and psilocybin were moderate, with psilocybin causing a higher increase in diastolic blood pressure compared with LSD, and LSD showing a trend toward an increase in heart rate compared with psilocybin. The tolerability of mescaline, LSD, and psilocybin was comparable, with mescaline at both doses inducing slightly more subacute adverse effects (12–24 h) than LSD and psilocybin. Clear distinctions were seen in the duration of action between the three substances. Mescaline had the longest effect duration (mean: 11.1 h), followed by LSD (mean: 8.2 h), and psilocybin (mean: 4.9 h). Plasma elimination half-lives of mescaline and LSD were similar (approximately 3.5 h). The longer effect duration of mescaline compared with LSD was due to the longer time to reach maximal plasma concentrations and related peak effects. Mescaline and LSD, but not psilocybin, enhanced circulating oxytocin. None of the substances altered plasma brain-derived neurotrophic factor concentrations. In conclusion, the present study found no evidence of qualitative differences in altered states of consciousness that were induced by equally strong doses of mescaline, LSD, and psilocybin. The results indicate that any differences in the pharmacological profiles of mescaline, LSD, and psilocybin do not translate into relevant differences in the subjective experience. ClinicalTrials.gov identifier: NCT04227756.
Normative tDCS over V5 and FEF reveals practice-induced modulation of extraretinal smooth pursuit mechanisms, but no specific stimulation effect
The neural networks subserving smooth pursuit eye movements (SPEM) provide an ideal model for investigating the interaction of sensory processing and motor control during ongoing movements. To better understand core plasticity aspects of sensorimotor processing for SPEM, normative sham, anodal or cathodal transcranial direct current stimulation (tDCS) was applied over visual area V5 and frontal eye fields (FEF) in sixty healthy participants. The identical within-subject paradigm was used to assess SPEM modulations by practice. While no specific tDCS effects were revealed, within- and between-session practice effects indicate plasticity of top-down extraretinal mechanisms that mainly affect SPEM in the absence of visual input and during SPEM initiation. To explore the potential of tDCS effects, individual electric field simulations were computed based on calibrated finite element head models and individual functional localization of V5 and FEF location (using functional MRI) and orientation (using combined EEG/MEG) was conducted. Simulations revealed only limited electric field target intensities induced by the applied normative tDCS montages but indicate the potential efficacy of personalized tDCS for the modulation of SPEM. In sum, results indicate the potential susceptibility of extraretinal SPEM control to targeted external neuromodulation (e.g., personalized tDCS) and intrinsic learning protocols.
Clean-Label Starch Modifications: Dry Heat Treatment in Combination with Ion Exchange
Potato starch offers the unique potential of mineral enrichment through the presence of phosphorylated amylopectin chains. This property was utilised in a straightforward dual modification of native potato starch by combining mineral enrichment with dry heat treatments (DHT). DHT itself (110–130 °C, 3–6% moisture, 2 h) affords potato starches with lower viscosity and gelatinisation temperatures and higher contents of digestible starch. Prior ion exchange with Na+, K+, Mg2+, and Ca2+ enhanced the versatility of dry heat treatments. This study demonstrates the fine-tuning of functional properties (rheology) of these novel, dual-modified starches. Of special interest are magnesium and calcium due to their nutritional value and their valency, allowing ionic cross-linking. The present study contributes to the understanding of starch–ion interactions in DHT, clearly highlighting the role of specific ion effects, as per the Hofmeister series (K+ > Na+ and Ca2+ > Mg2+), in addition to the reversible ionic cross-linking effect of divalent cations. This knowledge is of use for potential substitution of chemically modified starches in food products, serving relevant trends and needs of today’s food industry for clean-label starches.
Global analysis of a predator–prey model with variable predator search rate
We consider a modified Holling-type II predator–prey model, based on the premise that the search rate of predators is dependent on the prey density, rather than constant. A complete analysis of the global behavior of the model is presented, and shows that the model exhibits a dichotomy similar to the classical Holling-type II model: either the coexistence steady state is globally stable; or it is unstable, and then a unique, globally stable limit cycle exists. We discuss the similarities, but also important differences between our model and the Holling-type II model. The main differences are that: 1. The paradox of enrichment which always occurs in the Holling-type II model, does not always occur here, and 2. Even when the paradox of enrichment occurs, predators can adapt by lowering their search rate, and effectively stabilize the system.
Generation of an Oncolytic Herpes Simplex Virus 1 Expressing Human MelanA
Robust anti-tumor immunity requires innate as well as adaptive immune responses. We have shown that plasmacytoid dendritic cells develop killer cell-like activity in melanoma cell cocultures after exposure to the infectious but replication-deficient herpes simplex virus 1 (HSV-1) 106S. To combine this innate effect with an enhanced adaptive immune response, the gene encoding human MelanA/MART-1 was inserted into HSV-1 106S via homologous recombination to increase direct expression of this tumor antigen. Infection of Vero cells using this recombinant virus confirmed MelanA expression by Western blotting, flow cytometry, and immunofluorescence. HSV-1 106S-MelanA induced expression of the transgene in fibroblast and melanoma cell lines not naturally expressing MelanA. Infection of a melanoma cell line with CRISPR-Cas9-mediated knockout of MelanA confirmed expression of the transgene in the viral context. Dependent on MelanA expression, infected fibroblast and melanoma cell lines induced degranulation of HLA-matched MelanA-specific CD8 T cells, followed by killing of infected cells. To study infection of immune cells, we exposed peripheral blood mononuclear cells and -differentiated macrophages to the parental HSV-1 106S, resulting in expression of the transgene GFP in CD11c cells and macrophages. These data provide evidence that the application of MelanA-encoding HSV-1 106S could enhance adaptive immune responses and re-direct MelanA-specific CD8 T cells to tumor lesions, which have escaped adaptive immune responses via downregulation of their tumor antigen. Hence, HSV-1 106S-MelanA harbors the potential to induce innate immune responses in conjunction with adaptive anti-tumor responses by CD8 T cells, which should be evaluated in further studies.
Influence of quality of intensive care on quality of life/return to work in survivors of the acute respiratory distress syndrome: prospective observational patient cohort study (DACAPO)
Background Significant long-term reduction in health-related quality of life (HRQoL) is often observed in survivors of the acute respiratory distress syndrome (ARDS), and return to work (RtW) is limited. There is a paucity of data regarding the relationship between the quality of care (QoC) in the intensive care unit (ICU) and both HRQoL and RtW in ARDS survivors. Therefore, the aim of our study was to investigate associations between indicators of QoC and HRQoL and RtW in a cohort of survivors of ARDS. Methods To determine the influence of QoC on HRQoL and RtW 1 year after ICU-discharge, ARDS patients were recruited into a prospective multi-centre patient cohort study and followed up regularly after discharge. Patients were asked to complete self-report questionnaires on HRQoL (Short Form 12 physical component scale (PCS) and mental component scale (MCS)) and RtW. Indicators of QoC pertaining to volume, structural and process quality, and general characteristics were recorded on ICU level. Associations between QoC indicators and HrQoL and RtW were investigated by multivariable linear and Cox regression modelling, respectively. B values and hazard ratios (HRs) are reported with corresponding 95% confidence intervals (CIs). Results 877 (of initially 1225 enrolled) people with ARDS formed the DACAPO survivor cohort, 396 were finally followed up to 1 year after discharge. The twelve-month survivors were characterized by a reduced HRQoL with a greater impairment in the physical component (Md 41.2 IQR [34–52]) compared to the mental component (Md 47.3 IQR [33–57]). Overall, 50% of the patients returned to work. The proportion of ventilated ICU patients showed significant negative associations with both 12 months PCS (B = − 11.22, CI −20.71; − 1,74) and RtW (HR = 0,18, CI 0,04;0,80). All other QoC indicators were not significantly related to outcome. Conclusions Associations between ICU QoC and long-term HrQoL and RtW were weak and largely non-significant. Residual confounding by case mix, treatment variables before or during ICU stay and variables pertaining to the post intensive care period (e.g. rehabilitation) cannot be ruled out. Trial registration Clinicaltrials.govNCT02637011 . (December 22, 2015, retrospectively registered)
Global analysis of a predator-prey model with variable predator search rate
We consider a modified Rosenzweig-MacArthur predator-prey model, based on the premise that the search rate of predators is dependent on the prey density, rather than constant. A complete analysis of the global behavior of the model is presented, and shows that the model exhibits a dichotomy similar to the classical Rosenzweig-MacArthur model: either the coexistence steady state is globally stable; or it is unstable, and then a unique, globally stable limit cycle exists. We discuss the similarities, but also important differences between our model and the Rosenweig-MacArthur model. The main differences are that: 1. The paradox of enrichment which always occurs in the Rosenzweig-MacArthur model, does not always occur here, and 2. Even when the paradox of enrichment occurs, predators can adapt by lowering their search rate, and effectively stabilize the system.