Effectiveness of opioid switching for dyspnea and its predictors in cancer patients: a single-center retrospective observational study.

BACKGROUND: Morphine is the most used opioid for dyspnea, but other opioids such as oxycodone and fentanyl are increasingly used, and opioid switching to these is sometimes undertaken. No studies have verified the effectiveness of opioid switching for relief of dyspnea. We retrospectively investigated the effectiveness of opioid switching for dyspnea and its predictors. METHODS: All patients with opioid switching for dyspnea during hospitalization at Komaki City Hospital from January 2019 to August 2022 were included. Opioid switching was defined as a change to another opioid, and the assessment period for evaluating the effectiveness and adverse events of opioid switching was set as 1 week. Patients with Numeric Rating Scale or Japanese version of the Support Team Assessment Schedule reduction for dyspnea of at least 1, or with clear improvement based on medical records, were considered valid. Mitigating factors for dyspnea were identified using logistic regression analysis. RESULTS: Of the 976 patients with opioid switching, 57 patients had opioid switching for relief of dyspnea. Of these, opioid switching was effective in 21 patients (36.8%). In a multivariate analysis, older patients (odds ratio: 5.52, 95% CI: 1.50-20.20, P < 0.01), short prognosis for post-opioid switching (odds ratio: 0.20, 95% CI: 0.04-0.87, P = 0.03) and cachexia (odds ratio: 0.12, 95% CI: 0.02-0.64, P < 0.01) were significantly associated with opioid switching effects for dyspnea. There were no serious adverse events after opioid switching. CONCLUSION: This study indicates that opioid switching for dyspnea may have some effect. Furthermore, opioid switching for dyspnea may be more effective in older patients and less effective in terminally ill patients or in those with cachexia.

N-terminal acetyltransferase NatB regulates Rad51-dependent repair of double-strand breaks in Saccharomyces cerevisiae.

Homologous recombination (HR) is a highly accurate mechanism for repairing DNA double-strand breaks (DSBs) that arise from various genotoxic insults and blocked replication forks. Defects in HR and unscheduled HR can interfere with other cellular processes such as DNA replication and chromosome segregation, leading to genome instability and cell death. Therefore, the HR process has to be tightly controlled. Protein N-terminal acetylation is one of the most common modifications in eukaryotic organisms. Studies in budding yeast implicate a role for NatB acetyltransferase in HR repair, but precisely how this modification regulates HR repair and genome integrity is unknown. In this study, we show that cells lacking NatB, a dimeric complex composed of Nat3 and Mdm2, are sensitive to the DNA alkylating agent methyl methanesulfonate (MMS), and that overexpression of Rad51 suppresses the MMS sensitivity of nat3Δ cells. Nat3-deficient cells have increased levels of Rad52-yellow fluorescent protein foci and fail to repair DSBs after release from MMS exposure. We also found that Nat3 is required for HR-dependent gene conversion and gene targeting. Importantly, we observed that nat3Δ mutation partially suppressed MMS sensitivity in srs2Δ cells and the synthetic sickness of srs2Δ sgs1Δ cells. Altogether, our results indicate that NatB functions upstream of Srs2 to activate the Rad51-dependent HR pathway for DSB repair.