"In vitro inhibition of human erythrocyte Acetylcholinesterase activity by Zinc and Mercury "

The effects of zinc and mercury on human erythrocyte acetylcholinestrase activity were studied. Blood used in this study was obtained from 24 apparently healthy individuals and after hemolysation, was treted with 3 diferent concentrations of zinc and mercury. Significant suppressions in acetylcholinestrase activity were recorded in treated samples by zinc and mercury. When compared to controls the remaining activity was found to be 53% with the highest concen.tration of zinc (2.1 mg/dl, p<0.01), 72% with the middle (1.4 mg/dl, p<0.01) and 85% with the lowest one (0.7 mg/dl, p<0.01). in the case of mercury, the remaining activity was found to be 55% with the highest concentration (8.4 ng/g , p<0.01 ), 72% with the middle (5.6 ng/g , p<0.01) and 79% with the lowest one (2.8 ng/g , p<0.01). mercury showed a good correlation between doses used and decreases in activity (r=0.98). zinc also showed a linear correlation ( r=0.99). the direct interaction of metal ions with acetylcholinestrase is proposed as a mechanism for depressed enzyme activity. It is concluded that zinc and mercury contamination during acetylcholinestrase measurement can be a source of error that must be taken in to account

Preparation and evaluation of electrospun nanofibers containing pectin and time-dependent polymers aimed for colonic drug delivery of celecoxib

Objective(s):The aim of this study was to prepare electrospun nanofibers of celecoxib using combination of time-dependent polymers with pectin to achieve a colon-specific drug delivery system for celecoxib. Materials and Methods:Formulations were produced based on two multilevel 22 full factorial designs. The independent variables were the ratio of drug:time-dependent polymer (X1) and the amount of pec­tin in formulations (X2). Electrospinning process was used for preparation of nanofibers. The spinning solutions were loaded in 5 mL syringes. The feeding rate was fixed by a syringe pump at 2.0 mL/h and a high voltage supply at range 10-18 kV was applied for electrospinning. Electrospun nanofibers were collected and evaluated by scanning electron microscopy and drug release in the acid and buffer with pH 6.8 with and without pectinase. Results:Electrospun nanofibers of celecoxib with appropriate morphological properties were produced via electrospinning process. Drug release from electrospun nanofibers was very low in the acidic media; while, drug release in the simulated colonic media was the highest from formulations containing pectin. Conclusion: Formulation F2 (containing drug:ERS with the ratio of 1:2 and 10% pectin) exhibited acceptable morphological characteristics and protection of drug in the upper GI tract and could be a good candidate as a colonic drug delivery system for celecoxib

Effect of Seed Priming on Lodging Indices of Rice (Oryza sativa L.) Cultivars in Direct Seeding Method

In order to evaluate the effect of seed priming on lodging-related characteristics in direct seeding method, a study was conducted in a factorial randomized complete block design with four replicates in the research field of Rice Research Institute of Iran (Rasht) for two years. The first factor consisted of two rice cultivars (Khazar and Hashemi) and the second one consisted of ten levels of seed conditions encompassing, eight priming treatments including hydropriming, ascorbic acid, salicylic acid, CaCl2, cold, cold + heat, seed coating, and non-primed dry seed, all sown with seed tap technology along with linear direct seeding of germinated seeds and transplanting (25-days-old seedlings). Agronomic and morphological characteristics and resistance to lodging indices were measured. The results showed that there were significant differences between two cultivars and ten levels of seed conditions in morphological traits and lodging resistance indices. Mean comparisons and correlation analyses showed that grain yield (5142 kgha-1), resistance to fracture in third and fourth internodes (549 and 704 Newton, respectively) in Khazar were higher than those of Hashemi. There was a significant difference between planting methods (direct-seeded and transplanting) in terms of lodging resistance. Maximum indicators in the third and fourth internode bending momentum (1060 and 1708 gcm-1) were observed in the transplanting method. Hydropriming treatment had significant effect on fourth internode thickness in cultivar Khazar. Priming treatments appeared to leave significant effect on resistance to lodging in different planting methods in a cultivar-specific manner. &nbsp