The DNA damage response (DDR) is a dynamic process that is crucial for protecting the cell from challenges to genome integrity. Although many genome-wide studies in Saccharomyces cerevisiae have identified genes that contribute to resistance to DNA-damaging agents, more work is needed to elucidate the changes in genetic interaction networks in response to DNA lesions. Here we used conditional epistatic miniarray profiling to analyze the genetic interaction networks of the DDR genes RTT107, SLX4, and HRQ1 under three DNA-damaging conditions: camptothecin, hydroxyurea, and methyl methanesulfonate. Rtt107 and its interaction partner Slx4 are targets of the checkpoint kinase Mec1, which is central to the DDR-signaling cascades. Hrq1 recently was identified as a novel member of the RecQ helicase family in S. cerevisiae but is still poorly characterized. The conditional genetic networks that we generated revealed functional insights into all three genes and showed that there were varied responses to different DNA damaging agents. We observed that RTT107 had more genetic interactions under camptothecin conditions than SLX4 or HRQ1, suggesting that Rtt107 has an important role in response to this type of DNA lesion. Although RTT107 and SLX4 function together, they also had many distinct genetic interactions. In particular, RTT107 and SLX4 showed contrasting genetic interactions for a few genes, which we validated with independently constructed strains. Interestingly, HRQ1 had a genetic interaction profile that correlated with that of SLX4 and both were enriched for very similar gene ontology terms, suggesting that they function together in the DDR.

INTRODUCTION: There is a lack of quantitative data on healthcare professionals (HCPs) time dedicated to nebulized chronic obstructive pulmonary disease (COPD) therapy in inpatient and long-term care (LTC) settings. Using time and motion methodology, we quantified HCP time and opportunity costs (time and materials) associated with nebulized COPD therapy in inpatient and LTC settings and estimated efficiencies of changing to once-daily therapy. METHODS: A case report form was built to reflect local nebulization workflow. Primary outcomes were mean active HCP time per predefined task and mean total active HCP time associated with short-acting beta agonist (SABA) and SABA/short-acting muscarinic antagonist (SAMA) combination nebulization processes. RESULTS: Twenty observations occurred within each setting. Inpatient observations included three SABA and 17 SABA/SAMA (from 18 different patients), and LTC observations included five SABA and 15 SABA/SAMA (from eight different patients). Mean total process time was 16.12 min in the inpatient setting (95% CI 14.48-17.76) and 21.0 min in the LTC setting (95% CI 18.8-23.2), with the actual nebulization comprising over 50% of process time for both. In LTC, CIs suggest a difference by cognitive impairment status: mean 24.1 min (95% CI 21.3-26.9) if cognitively impaired versus 19.0 min (95% CI 16.1-21.8) if not. In the inpatient setting, the estimated process time/admission was 7.8 h; a once-daily nebulized drug would require only 2.3 h. In LTC, the estimated process time was 32.1 h/month; a once-daily nebulized drug would require only 13.7 h/month. Estimated nebulization cost was $243/admission for current versus $72 for once-daily dosing in inpatient, and $1177/month versus $504 in LTC. CONCLUSIONS: The nebulization process for COPD patients in both inpatient and LTC settings consumes considerable HCP time. A switch from SABA or SABA/SAMA to a drug with a once-daily nebulization frequency could generate substantial time savings depending on the setting and site characteristics.