OBJECTIVEInhibition of acetylcholinesterase (AChE) in human brain caused by phoxim or phoxim oxon, their reactivation with oxime and aging of phosphorylated AChE were studied and compared in vitro.

METHODSMicro-colorispectrophotometric assay was used to determine the activity of AChE.

RESULTSThe pI(50) of inhibition of AChE in human brain by phoxim and phoxim oxon were 5.39 and 5.77, respectively, whereas the pI(90) were 4.60 and 5.00, respectively. The reactivation rate of 0.1 mmol/L of pralidoxime (2-PAM), obidoxime (LüH(6)), trimedoxime (TMB-4) and pyramidoxime (HI-6) for phoxim-inhibited AChE in human brain was 65%, 97%, 91% and 56%, respectively, and their reactivation rate for phoxim oxon-inhibited AChE in human brain was 97%, 87%, 99% and 89%, respectively. The optimal reactivator for phoxim and phoxim oxon-inhibited AChEs was LüH(6) and TMB-4, respectively. The half aging time of phoxim and phoxim oxon inhibited phosphorylated AChEs were 39 and 28 hours, respectively, and the 99% aging time were 256 and 186 hours, respectively.

CONCLUSIONSLüH(6) or TMB-4 should be used at the earlier as possible after poisoning with phoxim and phoxim oxon, and the reactivator should be consecutively used for more than seven days, even after their acute symptoms have been well controlled.

Acetylcholinesterase ; metabolism ; Brain ; drug effects ; enzymology ; Cholinesterase Inhibitors ; pharmacology ; Cholinesterase Reactivators ; pharmacology ; Enzyme Stability ; Humans ; In Vitro Techniques ; Obidoxime Chloride ; pharmacology ; Organothiophosphorus Compounds ; pharmacology ; Oximes ; pharmacology ; Paraoxon ; pharmacology ; Pralidoxime Compounds ; pharmacology ; Time Factors ; Trimedoxime ; pharmacology

Objective     To systematically evaluate the safety, efficacy, and economics of intracardiac echocardiography (ICE) versus transesophageal echocardiography (TEE) in left atrial appendage occlusion (LAAO). Methods     PubMed, EMbase, The Cochrane Library, CBM, CNKI, VIP and WanFang Database were systematically  searched to collect relevant studies on comparing ICE and TEE-guided LAAO from inception to June 15th, 2022. Two reviewers independently screened the literatures, extracted the data, and assessed the risk of bias of the included studies. Meta-analyses were performed using RevMan 5.3 and R 4.0.3. Retrospective cohort studies were excluded for sensitivity analysis. Subgroup analyses were performed based on the types of occluder and ICE catheter. Results     A total of 14 studies with 6 599 patients were included. Meta-analyses showed no statistical differences in technical success rate, overall complications, device embolization, peri-device leakage, device-related thrombus, stroke, vascular complications, bleeding, operation time, fluoroscopy time, or contrast agent volume between the ICE and TEE-guided LAAO. The total in-room time (MD=–33.47 min, 95%CI –41.20 to –25.73, P<0.000 01) and radiation dosage (MD=–170.20 mGy, 95%CI –309.79 to –30.62, P=0.02) were lower in the ICE group than those in the TEE group, whereas the incidence of pericardial effusion/tamponade was higher than the TEE group (RR=1.57, 95%CI 1.01 to 2.45, P=0.048). Except for pericardial effusion/tamponade, subgroup analyses and sensitivity analysis showed similar results. The analysis based on the cost data from the United States showed comparable or even lower total costs for ICE versus TEE, but comparative domestic cost studies were lacking. Conclusion     Current evidence suggests that ICE-guided LAAO can reduce radiation dosage and total in-room time, and there is no statistical difference in the overall complication rate between the two groups. Owing to the limitations of sample size and quality of the included studies, the conclusion still needs to be verified by large sample size and high-quality randomized controlled trials.