Biochemical investigations into the mutagenic potential of 8-oxo-2'-deoxyguanosine using nucleotide analogues.

8-Oxo-2'-deoxyguanosine (OdG) is an abundant DNA lesion produced during oxidative damage to DNA. It can form relatively stable base pairs with both dC and dA that mimic natural dG:dC and dT:dA base pairs, respectively. Thus, when in the template strand, OdG can direct the insertion of either dCTP or dATP during replication, the latter of which can lead to a dG → T transversion. The potential for OdG to cause mutation is dependent on the preference for dCTP or dATP insertion opposite OdG, as well as the ability to extend past the resulting base pairs. The C2-amine and C8-oxygen could play major roles during these reactions since both would lie outside the Watson-Crick cognate base pairs shape in the major groove when OdG base pairs to dA and dC, respectively, and both have the ability to form strong interactions, like hydrogen bonds. To gain a more generalized understanding of how the C2-amine and C8-oxygen of OdG affect its mutagenic potential, the incorporation opposite and extension past seven analogues of dG/OdG that vary at C2 and/or C8 were characterized for three DNA polymerases, including an exonuclease-deficient version of the replicative polymerase from RB69 (RB69), human polymerase (pol) ß, and polymerase IV from Sulfolobus solfataricus P2 (Dpo4). Based on the results from these studies, as well as those from previous studies with RB69, pol ß, Dpo4, and two A-family polymerases, the influence of the C2-amine and C8-oxygen during each incorporation and extension reaction with each polymerase is discussed. In general, it appears that when the C2-amine and the C8-oxygen are in the minor groove, they allow OdG to retain interactions that are normally present during insertion and extension. However, when the two groups are in the major groove, they each tend to form novel active site interactions, both stabilizing and destabilizing, that are not present during insertion and extension with natural DNA.

Improving Guidance and Maternal Knowledge Retention After Well-Newborn Unit Discharge.

BACKGROUND AND OBJECTIVES: In 2015, the American Academy of Pediatrics published a policy statement to provide best practices on mother-infant discharge criteria, including the delivery of anticipatory guidance to mothers of healthy newborns. In our large health system with a mix of hospital types, no standard approach to or measurement of the effectiveness of newborn discharge guidance exists. At one community well-newborn unit, we aimed to increase maternal knowledge retention of newborn guidance from 69% to 90%. METHODS: Data about newborn guidance effectiveness were collected by assessing maternal knowledge retention through phone follow-up quizzes. By using quality improvement methodology and informed by American Academy of Pediatrics guidelines and curricular and adult learning theory, we standardized a multidisciplinary approach to this education. Interventions included checklist, scripts, temperature-taking demonstration, gift thermometer, staff education, car seat infant mannequin, and car seat training video for staff. RESULTS: Over a 1-year period, 333 mothers were interviewed after discharge from the well-newborn unit. Baseline data over the first 3 months (n = 93) showed poor maternal knowledge retention (69% correct answers). Common incorrect answers were on newborn urination habits, car seat harness clip positioning, and fever recognition. After restructuring the educational process, special cause was achieved after 3 months, with a shift of the average of correct answers to 83% followed by a second shift to 86%. CONCLUSIONS: The implementation of interventions to standardize newborn discharge guidance resulted in marked and sustained improvement in maternal knowledge after well-newborn unit discharge. Our next step is to enhance the process by using videos with systemwide implementation.

Combination of post-operative radiotherapy and cetuximab for high-risk cutaneous squamous cell cancer of the head and neck: A propensity score analysis.

OBJECTIVES: The objective of this study was to investigate the safety, tolerability and preliminary efficacy of radiotherapy plus cetuximab in high risk CSCC patients. MATERIALS AND METHODS: Patients with high-risk CSCC diagnosed between 2006 and 2013 were analyzed. Patients were divided into two groups: radiotherapy alone versus radiotherapy plus cetuximab. Among 68 patients meeting study criteria, we identified 29 treated with cetuximab plus RT and 39 with RT alone. Primary analysis examined disease-free and overall survival, freedom from local and distant recurrence in the propensity score matched cohort. Propensity score analysis was performed with weighted factors including: Charlson Comorbidity Index score, age. KPS, primary location, T and N stage, recurrent status, margin status, LVSI, PNI and grade. Toxicity was assessed using the CTCAE v4.0. RESULTS: Median follow-up for living patients was 30 months. Patients in the cetuximab group were more likely to have advanced N stage, positive margins and recurrent disease. After propensity score matching the groups were well balanced. Six patients experienced ≥ grade 3 acute toxicity in the cetuximab group. The 1-year, 2-year and 5-year progression free survival (PFS) for patients in the cetuximab group were 86%, 72% and 66%, respectively. The 1-year, 2-year and 5-year overall survival (OS) for patients in the cetuximab group was 98%, 80% and 80%, respectively. CONCLUSIONS: Although limited by small numbers, the combination of cetuximab and radiotherapy in CSCC appears well tolerated there were more long-term survivors and less distant metastasis in the cetuximab group. These promising finding warrant further studies.