Whole-mitogenome analysis unveils previously undescribed genetic diversity in cane toads across their invasion trajectory.

Invasive species offer insights into rapid adaptation to novel environments. The iconic cane toad (Rhinella marina) is an excellent model for studying rapid adaptation during invasion. Previous research using the mitochondrial NADH dehydrogenase 3 (ND3) gene in Hawai'ian and Australian invasive populations found a single haplotype, indicating an extreme genetic bottleneck following introduction. Nuclear genetic diversity also exhibited reductions across the genome in these two populations. Here, we investigated the mitochondrial genomics of cane toads across this invasion trajectory. We created the first reference mitochondrial genome for this species using long-read sequence data. We combined whole-genome resequencing data of 15 toads with published transcriptomic data of 125 individuals to construct nearly complete mitochondrial genomes from the native (French Guiana) and introduced (Hawai'i and Australia) ranges for population genomic analyses. In agreement with previous investigations of these populations, we identified genetic bottlenecks in both Hawai'ian and Australian introduced populations, alongside evidence of population expansion in the invasive ranges. Although mitochondrial genetic diversity in introduced populations was reduced, our results revealed that it had been underestimated: we identified 45 mitochondrial haplotypes in Hawai'ian and Australian samples, none of which were found in the native range. Additionally, we identified two distinct groups of haplotypes from the native range, separated by a minimum of 110 base pairs (0.6%). These findings enhance our understanding of how invasion has shaped the genetic landscape of this species.

Restriction of oxycodone in the emergency department (ROXY-ED): A randomised controlled trial.

Background: The prescription of opioids in emergency care has been associated with harm, including overdose and dependence. The aim of this trial was to assess restriction of access to oxycodone (ROXY), in combination with education and guideline modifications, versus education and guideline modifications alone (standard care) to reduce oxycodone administration in the Emergency Department (ED). Methods: An unblinded, active control, randomised controlled trial was conducted in an adult tertiary ED. Participants were patients aged 18-75 years who had analgesics administered in the ED. The primary intervention was ROXY, through removal of all oxycodone immediate release tablets from the ED imprest, with availability of a small supply after senior clinician approval. The intervention did not restrict prescription of discharge medications. The primary outcome measure was oxycodone administration rates. Secondary outcomes were administration rates of other analgesic medications, time to initial analgesics and oxycodone prescription on discharge. Results: There were 2258 patients eligible for analysis. Oxycodone was administered to 80 (6.1%) patients in the ROXY group and 221 (23.3%) patients in the standard care group (relative risk (RR) 0.26; 95% CI: 0.21 to 0.33; p < .001). Tapentadol was prescribed more frequently in the ROXY group (RR 2.17; 95% CI: 1.71-2.74), while there were no differences in prescription of other analgesic medications. On discharge, significantly fewer patients were prescribed oxycodone (RR 0.51; 95% CI: 0.39-0.66) and no differences were observed in prescription rates of other analgesic medications. There was no difference in time to first analgesic (HR 0.94; 95% CI: 0.86-1.02). Conclusions: Restricted access to oxycodone was superior to education and guideline modifications alone for reducing oxycodone use in the ED and reducing discharge prescriptions of oxycodone from the ED. The addition of simple restrictive interventions is recommended to enable rapid changes to clinician behaviour to reduce the potential harm associated with the prescribing of oxycodone in the ED.