Effect of intravenous dexamethasone on the anaesthetic characteristics of peripheral nerve block: a double-blind, randomised controlled, dose-response volunteer study.

BACKGROUND: Intravenous dexamethasone is thought to prolong the duration of peripheral nerve block, but the dose-response relationship remains unclear. The aim of this volunteer study was to evaluate the dose-response effect of i.v. dexamethasone on the prolongation of median nerve block. METHODS: In a double-blind, randomised controlled study, 18 volunteer subjects received two median nerve blocks separated by a washout period. One block was conducted alongside an infusion of saline and the other alongside i.v. dexamethasone 2, 4, or 8 mg. The primary outcome was time to return of normal pinprick sensation. Secondary outcomes included thermal quantitative sensory testing (QST) for the time to return of cold detection threshold (CDT), warm detection threshold (WDT), cold pain threshold (CPT), heat pain threshold (HPT), area under QST curves, grip strength, and the incidence of adverse effects. RESULTS: The primary outcome, time to recovery of pinprick sensation, was similar between volunteers receiving saline or i.v. dexamethasone, regardless of dose (P=0.99). The time to recovery of QST milestones was similar between groups, although area under QST curves indicated prolongation of CDT (0 vs 8 mg, P=0.002) and WDT (0 vs 2 mg, P=0.008; 0 vs 4 mg, P=0.001; 0 vs 8 mg, P<0.001). There was no difference in motor recovery or adverse effects. CONCLUSIONS: Intravenous dexamethasone failed to significantly prolong the duration of pinprick anaesthesia regardless of dose. However, area under QST curve analysis indicated a dose-independent prolongation of CDT and WDT, the clinical significance of which is unclear. CLINICAL TRIAL REGISTRATION: NCT02864602 (clinicaltrials.gov).

Chemical curation to improve data accuracy: recent development of the 3DMET database.

We have developed a three-dimensional structure database of natural metabolites (3DMET). Early development of the 3DMET database relied on content auto-generated from 2D-structures of other chemical databases. From 2009, we began manual curation, obtaining new compounds from published works. In the process of curation, problems of digitizing 3D-structures from structure drawings of documents were accumulated. As the same as auto-generation, structure drawings should be also payed attention about stereochemistry. Our experiences in manual curation of 3DMET, as described herein, may be useful to others in this field of research and for the development of supporting systems of a chemical structure database. Manual curation is still necessary for proper database entry of the 3D-configurations of chiral atoms, a problem encountered frequently among natural products.