Effect of thiopental sodium and barbitone sodium on the total acetylcholine content and acetylcholinesterase activity in the brain tissue of Arvicanthis niloticus

The total ACh content and AChE activity were determined 1 hr after the i.p. injection of different doses of thiopental sodium (5, 10 and 20 mg/ml/100 g body wt) and barbitone sodium (20, 40 and 80 mg/ml/100 g body wt). The effect of different time intervals (1 min, 10 min, 30 min, 1 hr, 2.5 hr, 5 hr, 8 hr, 12 hr, 24 hr and 48 hr) on the total ACh content and AChE activity was investigated after i.p. injection of 10 mg thiopental sodium and 40 mg barbitone sodium/ml/100 g body wt. Both thiopental sodium and barbitone sodium increased the total ACh content in the brain tissue of Arvicanthis niloticus. Both drugs inhibited the brain AChE activity. It is thought that the increase in the total ACh content in the brain tissue of Arvicanthis niloticus may be due to a decrease in the release of ACh from the neuronal tissue and a decrease in AChE activity.     

A comparison of machine learning algorithms for chemical toxicity classification using a simulated multi-scale data model

Background  

Bioactivity profiling using high-throughput in vitro assays can reduce the cost and time required for toxicological screening of environmental chemicals and can also reduce the need for animal testing. Several public efforts are aimed at discovering patterns or classifiers in high-dimensional bioactivity space that predict tissue, organ or whole animal toxicological endpoints. Supervised machine learning is a powerful approach to discover combinatorial relationships in complex in vitro/in vivo datasets. We present a novel model to simulate complex chemical-toxicology data sets and use this model to evaluate the relative performance of different machine learning (ML) methods.     

Effect of drugs on brain acetylcholine level in Gerbillus pyramidum

1. The quantitative estimation of total acetylcholine content in the whole brain tissue in normal Egyptian gerbil Gerbillus pyramidum, gives an average of 1.43 +/- 0.06 micrograms of acetylcholine chloride/g fresh brain tissue. 2. The brain acetylcholine level in Gerbillus pyramidum was generally found to vary with the changes induced in the brain activity by drugs. 3. Depressants caused a increase and convulsants a decrease in total brain acetylcholine level. 4. Phenytoin depressed the brain activity but lowered brain acetylcholine level.     

Immobilization of acetylcholinesterase in nanofibrous PVA/BSA membranes by electrospinning

Electrospinning, a simple and versatile method to fabricate nanofibrous supports, has attracted continuous attention in the field of enzyme immobilization. In this study, acetylcholinesterase (AChE) has been successfully immobilized in PVA nanofibers via electrospinning of a mixture of AChE, BSA as an enzyme stabilizing additive and PVA. The maximum activity recovery of immobilized AChE was about 40%. In comparison with free enzyme, the immobilized AChE showed improved stability while retaining a considerable amount of activity at lower pH values. Moreover, the immobilized AChE retained >34% of its initial activity when stored at 30°C for 100 days and retained 70% of its initial activity after ten consecutive reactor batch cycles.     

Palaeolimnological responses of nine North African lakes in the CASSARINA Project to recent environmental changes and human impact detected by plant macrofossil, pollen, and faunal analyses

This paper presents multi-proxy palaeolimnological analyses from recent sediments in the nine CASSARINA lakes in northernmost Africa, three from each of Morocco, Tunisia, and Egypt. The lakes are diverse, ranging from hypersaline to brackish lagoons and fresh-water lakes from high to low conductivity and pH. The macrofossils analysed include fruits, seeds, and vegetative remains of plants, lagoon and fresh-water Mollusca, a range of other aquatic animals, and from one site in each country, Ostracoda and Foraminifera. The diverse macrofossils are multi-proxy indicators of environmental change, and demonstrate changes in response to human activities in the catchments of all the lakes. The three Egyptian Nile Delta lakes have received massive inputs of fresh-water due to modifications of the flow of the R. Nile culminating in the Aswan High Dam built in 1964. Elsewhere, water withdrawal is frequently a serious threat. One lake with high biodiversity in Morocco has been drained and cultivated, and a rare acid-water lake in Tunisia is in danger of drying up. The internationally famous Garaet El Ichkeul in Tunisia, which was so important for birds, has become permanently saline with a loss of diversity. All the lakes are affected by agricultural and/or urban run-off and are experiencing changes as a result of human activities. Several are in a marginally sustainable condition, whereas others are permanently damaged.