Human small bowel as a useful tool to investigate smooth muscle effects of potential therapeutics in organophosphate poisoning

A pharmacologically pre-contracted smooth muscle bowel model for the study of highly-potent opioid receptor agonists and antagonists

Isolated organ models are a versatile tool for pharmacological and toxicological research. Small bowel has been used to assess the inhibition of smooth muscle contraction by opioids. In the present study, we set out to establish a pharmacologically stimulated rat bowel model. The effects of carfentanil, remifentanil and the new synthetic opioid U-48800 and their respective antagonists naloxone, nalmefene and naltrexone were studied in a small bowel model in rats. The IC₅₀ values of the tested opioids were as follows: carfentanil (IC₅₀ = 0.02 µmol/L, CI 0.02-0.03 µmol/L) ≫ remifentanil (IC₅₀ = 0.51 µmol/L, CI 0.40-0.66 µmol/L) ≫ U-48800 (IC₅₀ = 1.36 µmol/L, CI 1.20-1.54 µmol/L). The administration of the opioid receptor antagonists naloxone, naltrexone and nalmefene led to progressive, parallel rightward shifts of the dose-response curves. Naltrexone was most potent in antagonizing the effects of U-48800, whereas naltrexone and nalmefene were most effective in antagonizing the effects of carfentanil. In summary, the current model seems to be a robust tool to study opioid effects in a small bowel model without the necessity of using electrical stimulation.

Hemoperfusion in combination with hemofiltration for acute severe organophosphorus pesticide poisoning: A systematic review and meta-analysis

Background:

Acute severe organophosphorus pesticide poisoning (ASOPP) is one of the major diseases that endanger human life and health. However, the effects of conventional therapy including gastric lavages, mechanical ventilation, muscarinic antagonist drugs, and cholinesterase reactivators were uncertain. This meta-analysis aims to investigate the safety and efficacy of hemoperfusion combined with hemofiltration besides routine therapy for ASOPP.

Materials and Methods:

A comprehensive search for candidate publications was performed through PubMed, Medline, Cochrane Library, WanFang, Chinese Biomedical Literature, and China National Knowledge Infrastructure from database inception to May 12, 2020. The retrieved studies were screened by the predefined inclusion and exclusion criteria. The data of important end points were extracted. The risk ratio (RR) and weighted mean difference (WMD) were pooled for categorical variables and continuous variables, respectively. Meta-analyses and publication bias were conducted by using STATA software version 15.1.

Results:

A total of 11 randomized controlled trials with 811 patients were included. Compared to conventional therapy group, patients in the hemoperfusion plus hemofiltration group were significantly superior with regard to mortality (RR 0.38, 95% confidence interval [CI] [0.25, 0.57], P < 0.001), total atropine dosing (WMD −147.34 mg, 95% CI [−199.49, −95.18], P < 0.001), duration of mechanical ventilation (WMD −2.34 days, 95% CI [−3.77, −0.92], P < 0.001), cholinesterase recovery time (WMD −2.49 days, 95% CI [−3.14, −1.83], P < 0.001), and length of stay (WMD −4.52 days, 95% CI [−5.31, −3.73], P < 0.001).

Conclusion:

Combined hemoperfusion and hemofiltration was a very safe and effective treatment protocol for ASOPP, not only resulting in significantly decreased mortality but also resulting in reduced total atropine dosing, duration of mechanical ventilation, cholinesterase recovery time, and length of stay.