The production of polyhydroxybutyrate (PHB) by Alcaligenes eutrophus DSM 545 was studied in a synthetic medium with 3% glucose at pH 7.0 supplemented with several ammonium substrates and cane molasses. Growth was measured by dry cell weight, and the PHB content was measured by gas chromatography. The effects of ammonium sources such as sulfate, nitrate, phosphate, and chloride salts and those of different ammonium sulfate concentrations were evaluated. The best growth and PHB production were obtained with ammonium sulfate; however, NH 4 ؉ concentrations between 0.5 and 1.5 g/liter showed no significant difference. Ammonium sulfate was therefore used as the sole source of NH 4 ؉ for experiments with cane molasses as the growth activator. Optimal growth and PHB production were obtained with 0.3% molasses. However, the yields of biomass (39 to 48%) and PHB (17 to 26%) varied significantly among the different ammonium substrates and cane molasses concentrations.
Background
Long-term opioid use, which may have significant individual and societal impacts, has been documented in up to 20% of patients after trauma or orthopaedic surgery. The objectives of this scoping review were to systematically map the research on strategies aiming to prevent chronic opioid use in these populations and to identify knowledge gaps in this area.
Methods
This scoping review is reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) Checklist. We searched seven databases and websites of relevant organizations. Selected studies and guidelines were published between January 2008 and September 2021. Preventive strategies were categorized as: system-based, pharmacological, educational, multimodal, and others. We summarized findings using measures of central tendency and frequency along with p-values. We also reported the level of evidence and the strength of recommendations presented in clinical guidelines.
Results
A total of 391 studies met the inclusion criteria after initial screening from which 66 studies and 20 guidelines were selected. Studies mainly focused on orthopaedic surgery (62,1%), trauma (30.3%) and spine surgery (7.6%). Among system-based strategies, hospital-based individualized opioid tapering protocols, and regulation initiatives limiting the prescription of opioids were associated with statistically significant decreases in morphine equivalent doses (MEDs) at 1 to 3 months following trauma and orthopaedic surgery. Among pharmacological strategies, only the use of non-steroidal anti-inflammatory drugs and beta blockers led to a significant reduction in MEDs up to 12 months after orthopaedic surgery. Most studies on educational strategies, multimodal strategies and psychological strategies were associated with significant reductions in MEDs beyond 1 month. The majority of recommendations from clinical practice guidelines were of low level of evidence.
Conclusions
This scoping review advances knowledge on existing strategies to prevent long-term opioid use in trauma and orthopaedic surgery patients. We observed that system-based, educational, multimodal and psychological strategies are the most promising. Future research should focus on determining which strategies should be implemented particularly in trauma patients at high risk for long-term use, testing those that can promote a judicious prescription of opioids while preventing an illicit use, and evaluating their effects on relevant patient-reported and social outcomes.
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