"Oral ascorbic acid in combination with beta blockers in prevention of atrial fibrillation after Coronary Artery Bypass Graft "

Background: Adrenergic beta antagonists are not sufficient to prevent atrial fibrillation after coronary artery bypass graft (CABG). This study was designed to evaluate the effect of ascorbic acid as an adjunct to beta-blockers in prevention of post-CABG atrial fibrillation Methods: Patients who were more than 50 years old and scheduled to undergo CABG were included if they were treated with beta-blockers at least 1 week before surgery. Patients with previous history of atrial fibrillation, AV block, heart rate <50 /min, end-stage renal disease, severe pulmonary or liver disease and those who were taking digoxin or class I and III anti-arrhythmics or had pacemakers were not included. Ascorbic acid group were prescribed 2 gm of ascorbic acid, the night before the surgery, and 1 gm twice daily for 5 days after surgery. Beta blockers continued in both group after surgery. Telemetry monitoring was performed in ICU and Holter monitoring was performed for 4 days. Results: Fifty patients completed the study as ascorbic acid and 50 as control group. The population was 60.19 ± 7.14 years old and 67% were male. The incidence of postoperative atrial fibrillation was 4% in the ascorbic acid group and 26% in control group (odds ratio=0.119, 95% confidence interval: 0.025 to 0.558, P=0.002) Conclusion: Ascorbic acid is well-tolerated, relatively safe and seems effective. Therefore it can be prescribed as an adjunct to beta-blockers for prophylaxis of post-CABG atrial fibrillation

Preparation of chitosan nanoparticles by spray drying and their antibacterial activity

[[abstract]]Chitosan nanoparticles were prepared from chitosan with different molecular weight by spray drying method. The morphology of chitosan nanoparticles were characterized by SEM and size distribution and zeta potential values were determined. Effect of chitosan solution concentrations, molecular weight of chitosan (MMW, HMW and VHMW) and size of spray dryer nozzles on average size, size distribution and zeta potential values of chitosan nanoparticles were investigated. Moreover, the effect chitosan nanoparticles and chitosan nanoparticles/amoxicillin complex on Staphylococcus aureus was also tested. The results showed that the average size of chitosan nanoparticles were in the range of 95.5 to 395 nm and zeta potential values of 39.3 to 45.7 mV depended on concentration and molecular weight of chitosan. The lower concentration and molecular weight of chitosan were used, the smaller size of chitosan nanoparticles and the higher zeta potential values were obtained. The testing for antibacterial activity against S. aureus indicated that chitosan nanoparticles strongly inhibited the growth of bacteria with the minimum inhibitory concentration (MIC) of 20µg/mL, which were lower than that of chitosan solution and amoxicillin. The antibacterial capacity of chitosan nanoparticles also depended on size, zeta potential values and molecular weight of chitosan. Complex of chitosan nanoparticles/amoxicillin could improve antibacterial activity of amoxicillin.[[notice]]補正完畢[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子

Preparation of chitosan nanoparticles by TPP ionic gelation combined with spray drying, and the antibacterial activity of chitosan nanoparticles and a chitosan nanoparticle–amoxicillin complex

[[abstract]]Chitosan nanoparticles were prepared from chitosan with various molecular weights by tripolyphosphate (TPP) ionic gelation combined with a spray drying method. The morphologies and characteristics of chitosan nanoparticles were determined by TEM, FE-SEM and from their mean sizes and zeta potentials. The effect of chitosan molecular weight (130, 276, 760 and 1200 cPs) and size of spray dryer nozzle (4.0, 5.5 and 7.0 µm) on mean size, size distribution and zeta potential values of chitosan nanoparticles was investigated. The results showed that the mean size of chitosan nanoparticles was in the range of 166–1230 nm and the zeta potential value ranged from 34.9 to 59 mV, depending on the molecular weight of chitosan and size of the spray dryer nozzles. The lower the molecular weight of chitosan, the smaller the size of the chitosan nanoparticles and the higher the zeta potential. A test for the antibacterial activity of chitosan nanoparticles (only) and a chitosan nanoparticle–amoxicillin complex against Streptococcus pneumoniae was also conducted. The results indicated that a smaller chitosan nanoparticle and higher zeta potential showed higher antibacterial activity. The chitosan nanoparticle–amoxicillin complex resulted in improved antibacterial activity as compared to amoxicillin and chitosan nanopaticles alone. Using a chitosan nanoparticle–amoxicillin complex could reduce by three times the dosage of amoxicillin while still completely inhibiting S. pneumoniae.[[notice]]補正完