ARTICLE | doi:10.20944/preprints202112.0237.v1
Subject: Life Sciences, Other Keywords: religious fasting; daytime dry fasting; energy expenditure; body composition; microdialysis
Online: 14 December 2021 (13:06:26 CET)
Each year in March, adherents of the Bahá’í faith abstain from eating and drinking from sunrise to sunset for 19 days. Thus, Bahá’í fasting (BF) can be considered as a form of daytime dry fasting. We tested if BF decreases energy expenditure after a meal and improves anthropometric measures, and systemic and tissue-level metabolic parameters. This was a self-controlled cohort study with 11 healthy men. We measured anthropometric parameters, metabolic markers in venous blood, and pre- and postprandial energy metabolism at systemic (indirect calorimetry) and tissue (adipose tissue and skeletal muscle microdialysis) level, both before and during BF. During BF, we found reduced body weight, body mass index, body fat and blood glucose. Postprandial increase in energy expenditure was lower, diet-induced thermogenesis tended to be lower. In adipose tissue, perfusion, glucose supply and lipolysis were increased. In skeletal muscle, tissue perfusion did not change. Glucose supply and lipolysis were decreased. Glucose oxidation was increased, indicating an improved insulin sensitivity. BF may be a promising approach to losing weight and improving metabolism and health. However, outside the context of religiously-motivated fasting, skipping a meal rather in the evening (dinner cancelling) might be recommended, as metabolism appears to be reduced in the evening.
ARTICLE | doi:10.20944/preprints201806.0463.v1
Subject: Life Sciences, Molecular Biology Keywords: α-synuclein; amyloid fibrils; fibrillogenesis; thioflavin T; equilibrium microdialysis; binding parameters; structural polymorphism
Online: 28 June 2018 (10:50:40 CEST)
In this work α-synuclein amyloid fibrils, formation of which is a biomarker of the Parkinson’s disease, were investigated with the use of fluorescent probe thioflavin T (ThT). Experimental conditions of the protein fibrillogenesis were chosen so that a sufficient number of continuous measurements can be performed to characterize and analyze all stages of this process. The reproducibility of fibrillogenesis and the structure of the obtained aggregates (that is a critical point for their further investigation) were proved using a wide range of physical-chemical methods. For determination of ThT—α-synuclein amyloid fibrils binding parameters sample and reference solutions were prepared with the use of equilibrium microdialysis. By absorption spectroscopy of these solutions ThT—fibrils binding mode with the binding constant about 104 M−1 and stoichiometry of ThT per protein molecule about 1:8 was observed. Fluorescence spectroscopy of the same solutions with the subsequent correction of the recorded fluorescence intensity on the primary inner filter effect allowed to determine another mode of ThT binding to fibrils with the binding constant about 106 M−1 and stoichiometry about 1:2500. Analysis of photophysical characteristics of the dye molecules bound to the sites of different binding modes allowed to assume the possible localization of these sites. Obtained differences in the ThT binding parameters to amyloid fibrils formed from α-synuclein and other amyloidogenic proteins, as well as in the photophysical characteristics of the bound dye, confirmed the hypothesis of amyloid fibrils polymorphism.
REVIEW | doi:10.20944/preprints202208.0419.v1
Subject: Life Sciences, Other Keywords: Alcohol; Dynorphin; Kappa Opioid Receptor; DYN/KOR; Anxiety; Depression; Negative Affective States; Withdrawal; Microdialysis; Dynorphin-immunoreactivity
Online: 24 August 2022 (10:52:52 CEST)
Alcohol use disorder (AUD) represents major public and socioeconomic issues. Alcohol exerts its phar-macological effects by altering different neurotransmitter systems, such as g-aminobutyric acid (GABA), glutamate, opioids, etc. Recent evidence suggests that the dynorphin (DYN)/kappa opioid receptor (KOR) system mediates the negative affective states associated with alcohol withdrawal. This system is also in-volved in stress-mediated alcohol intake in alcohol-dependent subjects. The DYN/KOR system probably exerts its action in the central nucleus of the amygdala (CeA) to mediate the negative affective states as-sociated with alcohol withdrawal. This article aims to review the current literature regarding the role of the DYN/KOR system in the actions of alcohol. We first review the literature regarding the effect of alcohol on the level of the peptide and its receptor, and the role of the endogenous DYN/KOR system in alcohol reward and negative affective states associated with alcohol withdrawal is then discussed. We also review the literature regarding the effects of KOR ligands on these processes.