scholarly journals The Toxic Effect of Manganese on the Acetylcholinesterase Activity in Rat Brains

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
Vahid Yousefi Babadi ◽  
Leila Sadeghi ◽  
Kobra Shirani ◽  
Ali Akbar Malekirad ◽  
Mohammad Rezaei
Keyword(s):  
Toxic Effect ◽  
Ache Activity ◽  
Time Course ◽  
Acetylcholinesterase Activity ◽  
Time Intervals ◽  
Chronic Dose ◽  
Essential Nutrient ◽  
Short Time ◽  
Chronic Doses ◽  
Dose Dependent

Manganese (Mn) is a naturally occurring element and an essential nutrient for humans and animals. However, exposure to high levels of Mn may cause neurotoxic effects. Accumulation of manganese damages central nervous system and causes Parkinson’s disease-like syndrome called manganism. Mn neurotoxicity has been suggested to involve an imbalance between the DAergic and cholinergic systems. The pathological mechanisms associated with Mn neurotoxicity are poorly understood, but several reports have established it is mediated by changing of AChE activity that resulted in oxidative stress. Therefore we focused the effect of Mn in AChE activity in the rat’s brain by MnCl2injection intraperitoneally and analyzed their brains after time intervals. This study used different acute doses in short time course and different chronic doses at different exposing time to investigate which of them (exposing dose or time) is more important in Mn toxic effect. Results showed toxic effect of Mn is highly dose dependent and AChE activity in presence of chronic dose in 8 weeks reaches acute dose in only 2 days.

Correlation between organophosphate poisoning, acetylcholinesterase inhibition, and increased cyclic GMP levels in malathion-treated insects

1977 ◽  
Vol 55 (5) ◽  
pp. 534-542 ◽  
Author(s):  
Robert P. Bodnaryk
Keyword(s):  
Cyclic Gmp ◽  
Time Course ◽  
Acetylcholinesterase Activity ◽  
Acetylcholinesterase Inhibition ◽  
Organophosphate Poisoning ◽  
Abrupt Increase ◽  
Sarcophaga Bullata ◽  
Biochemical Lesion ◽  
Lag Period ◽  
Dose Dependent

Organophosphate poisoning with malathion caused large increases (up to 125 and 440%, respectively) in the level of cyclic GMP in larvae of Mamestra configurata Wlk. and in the fly Sarcophaga bullata Parker. Cyclic AMP was little affected. The malathion-induced increase in cyclic GMP was time and dose dependent. Time-course studies with the head and thorax of S. bullata demonstrated that the increase in cyclic GMP level occurred precipitously after a lag period of about 1 h, during which time the activity of acetylcholinesterase (EC 3.1.1.7) was progressively inhibited. The abrupt increase in cyclic GMP began when acetylcholinesterase activity had been inhibited to a sufficient extent to permit accumulation of acetylcholine. It is suggested that the accumulation of acetylcholine in the malathion-poisoned insects caused cyclic GMP levels to rise.Cyclic GMP may have a role in cholinergic transmission in normally functioning insect neural tissue. Increased levels of cyclic GMP induced by organophosphate and organochlorine (Bodnaryk, R. P. (1976) Can. J. Biochem. 54, 957–962) insecticides appear to be a vital and previously unrecognized biochemical lesion in insects poisoned by these compounds.

Transcription and Release of RNA in Isolated Nuclei from Parsley Cells

1979 ◽  
Vol 34 (5-6) ◽  
pp. 431-435 ◽  
Author(s):  
Klaus Großmann ◽  
Ursula Seitz ◽  
Hanns Ulrich Seitz
Keyword(s):  
Time Course ◽  
In Vitro Transcription ◽  
Petroselinum Crispum ◽  
Time Intervals ◽  
Transcription System ◽  
Freely Suspended ◽  
Polymerase I ◽  
Short Time ◽  
Transcriptional Process

Abstract An in vitro transcription system using nuclei from freely suspended callus cells of Petroselinum crispum is described. The use of a filtration technique allowed the measurement of transcription and release of RNA simultaneously over very short time intervals. The transcription showed a biphasic time course, with an early maximum at 2 and a later one at 20 minutes. The early maximum was ascribed to the activity of polymerase II (α-amanitin sensitive), the later to that of polymerase I. While the transcriptional process was independent of the temperature used for incubation up to 26 °C and even increased with temperatures above that, the release of RNA transcribed was inhibited by temperatures above 36 °C.

scholarly journals Antimicrobial Agent Triclosan Inhibits Acetylcholinesterase Activity in Vitro in a Dose-Dependent Manner

2021 ◽  
Author(s):  
Narasimha Pullaguri ◽  
Andrea Kagoo ◽  
Anamika Bhargava
Keyword(s):  
Antimicrobial Agent ◽  
Ache Activity ◽  
Acetylcholinesterase Activity ◽  
Consumer Products ◽  
In Vivo Studies ◽  
Dependent Manner ◽  
Human Health Effects ◽  
Dose Dependent

The antimicrobial agent, Triclosan, is widely used in many consumer products. It has been designated as a "contaminant of emerging concern (CEC)" because its exposure is known to cause adverse ecological and human health effects. Triclosan is not labelled as GRAS/GRAE (generally recognized as safe and effective), but its use is still prevailing. In vivo studies have revealed that exposure to triclosan results in a decreased acetylcholinesterase (AChE) activity. However mechanistic insights into AChE inhibition by triclosan are missing. Using in vitro AChE activity assay with purified AChE, we show that triclosan acts as a direct inhibitor of AChE and inhibits AChE activity in a dose-dependent manner. Given the function of AChE, any alteration in its activity can be neurotoxic. Our results provide important mechanistic insights into triclosan induced neurotoxicity with AChE as a target.

Destruction of Actin Filaments by Osmium Tetroxide

1977 ◽  
Vol 35 ◽  
pp. 466-467
Author(s):  
P. Maupin-Szamier ◽  
T. D. Pollard
Keyword(s):  
Actin Filaments ◽  
Time Course ◽  
Osmium Tetroxide ◽  
Rabbit Muscle ◽  
Muscle Actin ◽  
Sodium Phosphate Buffer ◽  
Transmission Electron ◽  
The Difference ◽  
Rates Of Decay ◽  
Short Time

We have studied the destruction of rabbit muscle actin filaments by osmium tetroxide (OSO4) to develop methods which will preserve the structure of actin filaments during preparation for transmission electron microscopy.Negatively stained F-actin, which appears as smooth, gently curved filaments in control samples (Fig. 1a), acquire an angular, distorted profile and break into progressively shorter pieces after exposure to OSO4 (Fig. 1b,c). We followed the time course of the reaction with viscometry since it is a simple, quantitative method to assess filament integrity. The difference in rates of decay in viscosity of polymerized actin solutions after the addition of four concentrations of OSO4 is illustrated in Fig. 2. Viscometry indicated that the rate of actin filament destruction is also dependent upon temperature, buffer type, buffer concentration, and pH, and requires the continued presence of OSO4. The conditions most favorable to filament preservation are fixation in a low concentration of OSO4 for a short time at 0°C in 100mM sodium phosphate buffer, pH 6.0.

Proposal of PV Output Estimate Method in Short Time Intervals

2016 ◽  
Vol 136 (12) ◽  
pp. 891-897 ◽  
Author(s):  
Katsuhiro Matsuda ◽  
Kazuhiro Misawa ◽  
Hirotaka Takahashi ◽  
Kenta Furukawa ◽  
Satoshi Uemura
Keyword(s):  
Time Intervals ◽  
Estimate Method ◽  
Short Time

EVALUATION OF SHORT TIME INTERVALS IN NORMAL AGING AND LATE-LIFE DEPRESSIONS

2020 ◽  
pp. 54-69
Author(s):  
Elena Yu. Balashova ◽  
◽  
Lika I. Mikeladze ◽  
Elena K. Kozlova ◽  
◽  
...  
Keyword(s):  
Late Life ◽  
Normal Aging ◽  
Time Intervals ◽  
Short Time

scholarly journals Neural Network Approach for Global Solar Irradiance Prediction at Extremely Short-Time-Intervals Using Particle Swarm Optimization Algorithm

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1213
Author(s):  
Ahmed Aljanad ◽  
Nadia M. L. Tan ◽  
Vassilios G. Agelidis ◽  
Hussain Shareef
Keyword(s):  
Neural Networks ◽  
Particle Swarm Optimization ◽  
Solar Irradiance ◽  
Particle Swarm ◽  
Time Interval ◽  
Time Intervals ◽  
Swarm Optimization ◽  
Backpropagation Neural Networks ◽  
Proposed Model ◽  
Short Time

Hourly global solar irradiance (GSR) data are required for sizing, planning, and modeling of solar photovoltaic farms. However, operating and controlling such farms exposed to varying environmental conditions, such as fast passing clouds, necessitates GSR data to be available for very short time intervals. Classical backpropagation neural networks do not perform satisfactorily when predicting parameters within short intervals. This paper proposes a hybrid backpropagation neural networks based on particle swarm optimization. The particle swarm algorithm is used as an optimization algorithm within the backpropagation neural networks to optimize the number of hidden layers and neurons used and its learning rate. The proposed model can be used as a reliable model in predicting changes in the solar irradiance during short time interval in tropical regions such as Malaysia and other regions. Actual global solar irradiance data of 5-s and 1-min intervals, recorded by weather stations, are applied to train and test the proposed algorithm. Moreover, to ensure the adaptability and robustness of the proposed technique, two different cases are evaluated using 1-day and 3-days profiles, for two different time intervals of 1-min and 5-s each. A set of statistical error indices have been introduced to evaluate the performance of the proposed algorithm. From the results obtained, the 3-days profile’s performance evaluation of the BPNN-PSO are 1.7078 of RMSE, 0.7537 of MAE, 0.0292 of MSE, and 31.4348 of MAPE (%), at 5-s time interval, where the obtained results of 1-min interval are 0.6566 of RMSE, 0.2754 of MAE, 0.0043 of MSE, and 1.4732 of MAPE (%). The results revealed that proposed model outperformed the standalone backpropagation neural networks method in predicting global solar irradiance values for extremely short-time intervals. In addition to that, the proposed model exhibited high level of predictability compared to other existing models.

Use of Isolated Tight Epithelia to Study the Site and Mode of Drug Action on Cell Membrane Transport: Effect of the Antipsychotic Agent Trifluoperazine

1990 ◽  
Vol 17 (3) ◽  
pp. 224-227
Author(s):  
Henning F. Bjerregaard
Keyword(s):  
Cell Membrane ◽  
Toxic Effect ◽  
Membrane Transport ◽  
Antipsychotic Agent ◽  
Na Transport ◽  
Tight Epithelia ◽  
Acute Toxic Effect ◽  
Cell Membrane Transport ◽  
Dose Dependent ◽  
Stimulation Of

The aim of the present study was to investigate the site and mode of trifluoperazine (TFP) action on cell membrane transport by the use of isolated frog skin. This cellular system gives access to the apical (outer) and basolateral (inner) membranes of the polarised epithelial cells. Both apical and basolateral TFP addition induced a dose-dependent stimulation of Na transport, and depolarised the cellular potential. The data indicate that TFP acts by increasing the Na permeability of the apical membrane. However, the mechanisms localised in the apical and basolateral membranes are quite different. Basolateral TFP addition increased Na transport due to a stimulation of PGE2 synthesis, whereas apical TFP addition abolished Na inhibition of the apical Na channels, and thereby enhanced the Na transport. An acute toxic effect on the electrophysiological parameters was noted after addition of high apical TFP concentrations (50–100μM). This toxic effect was dependent on the presence of Na in the apical solution.

scholarly journals Optimal Perturbations of an Oceanic Vortex Lens

Fluids ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 63 ◽  
Author(s):  
Thomas Meunier ◽  
Claire Ménesguen ◽  
Xavier Carton ◽  
Sylvie Le Gentil ◽  
Richard Schopp
Keyword(s):  
Normal Mode ◽  
Growth Rates ◽  
Time Interval ◽  
Time Intervals ◽  
Horizontal Structure ◽  
Azimuthal Wave ◽  
Wave Numbers ◽  
Non Linear ◽  
Long Time ◽  
Short Time

The stability properties of a vortex lens are studied in the quasi geostrophic (QG) framework using the generalized stability theory. Optimal perturbations are obtained using a tangent linear QG model and its adjoint. Their fine-scale spatial structures are studied in details. Growth rates of optimal perturbations are shown to be extremely sensitive to the time interval of optimization: The most unstable perturbations are found for time intervals of about 3 days, while the growth rates continuously decrease towards the most unstable normal mode, which is reached after about 170 days. The horizontal structure of the optimal perturbations consists of an intense counter-shear spiralling. It is also extremely sensitive to time interval: for short time intervals, the optimal perturbations are made of a broad spectrum of high azimuthal wave numbers. As the time interval increases, only low azimuthal wave numbers are found. The vertical structures of optimal perturbations exhibit strong layering associated with high vertical wave numbers whatever the time interval. However, the latter parameter plays an important role in the width of the vertical spectrum of the perturbation: short time interval perturbations have a narrow vertical spectrum while long time interval perturbations show a broad range of vertical scales. Optimal perturbations were set as initial perturbations of the vortex lens in a fully non linear QG model. It appears that for short time intervals, the perturbations decay after an initial transient growth, while for longer time intervals, the optimal perturbation keeps on growing, quickly leading to a non-linear regime or exciting lower azimuthal modes, consistent with normal mode instability. Very long time intervals simply behave like the most unstable normal mode. The possible impact of optimal perturbations on layering is also discussed.

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