Calorimetric Investigation of Copper Binding in the N-Terminal Region of the Prion Protein at Low Copper Loading: Evidence for an Entropically Favorable First Binding Event

Although the Cu²⁺-binding sites of the prion protein have been well studied when the protein is fully saturated by Cu²⁺, the Cu²⁺-loading mechanism is just beginning to come into view. Because the Cu²⁺-binding modes at low and intermediate Cu²⁺ occupancy necessarily represent the highest-affinity binding modes, these are very likely populated under physiological conditions, and it is thus essential to characterize them in order to understand better the biological function of copper–prion interactions. Besides binding-affinity data, almost no other thermodynamic parameters (e.g., Δ<i>H</i> and Δ<i>S</i>) have been measured, thus leaving undetermined the enthalpic and entropic factors that govern the free energy of Cu²⁺ binding to the prion protein. In this study, isothermal titration calorimetry (ITC) was used to quantify the thermodynamic parameters (<i>K</i>, Δ<i>G</i>, Δ<i>H</i>, and <i>T</i>Δ<i>S</i>) of Cu²⁺ binding to a peptide, PrP­(23–28, 57–98), that encompasses the majority of the residues implicated in Cu²⁺ binding by full-length PrP. Use of the buffer <i>N</i>-(2-acetomido)-aminoethanesulfonic acid (ACES), which is also a well-characterized Cu²⁺ chelator, allowed for the isolation of the two highest affinity binding events. Circular dichroism spectroscopy was used to characterize the different binding modes as a function of added Cu²⁺. The <i>K</i>_d values determined by ITC, 7 and 380 nM, are well in line with those reported by others. The first binding event benefits significantly from a positive entropy, whereas the second binding event is enthalpically driven. The thermodynamic values associated with Cu²⁺ binding by the Aβ peptide, which is implicated in Alzheimer’s disease, bear striking parallels to those found here for the prion protein

Living life as if I never had cancer : A study of the meaning of living well in adolescents and young adults who have experienced cancer.

BACKGROUND: Cancer diagnoses pose challenges to adolescents’ and young adults’ (AYA) physical, mental, and emotional health, and developmental tasks. In order for AYAs, caregivers, clinicians, and other collaborators to optimize health outcomes (coproduction of health), understanding what living well means for AYAs who have experienced cancer is necessary. The objective was to develop an empirical definition of “living well” for AYAs who have experienced cancer to broadly understand AYA values and priorities. This definition may ultimately guide future conversations between caregivers and AYAs, eliciting thorough, personal definitions of living well from individual AYAs. Such conversations may enhance AYA participation in coproducing their health. PROCEDURE: Qualitative analysis using a phenomenological approach of N = 30 structured Respecting Choices interviews conducted with AYAs (14–21 years; mean 84.2 [SD 69] months postcancer diagnosis with 21% on active treatment) from four tertiary pediatric hospitals in the context of a primary study of a pediatric advance care planning intervention trial. RESULTS: AYAs who have experienced cancer conceptualized “living well” as maintaining physical, mental, and emotional health, as well as engaging in purposeful, age-appropriate activities with people important to them. Living well had three components: living mindfully, living an identity as a healthy AYA, and spending time with friends and family. CONCLUSIONS: Conversations with AYAs who have experienced cancer elicited rich, complex concepts of “living well.” Provider initiation of discussions about living well may facilitate personalized goals of care conversations. This study may serve as the basis to design and prototype future clinical interventions to enhance AYA engagement

Effect of the Family-Centered Advance Care Planning for Teens with Cancer Intervention on Sustainability of Congruence About End-of-Life Treatment Preferences: A Randomized Clinical Trial

Importance: The effect of pediatric advance care planning (pACP) on the sustainability of end-of-life treatment preference congruence between adolescents with cancer and their families has not been examined. Objective: To evaluate the longitudinal efficacy of the Family-Centered Advance Care Planning for Teens with Cancer (FACE-TC) intervention to sustain adolescent-family congruence about end-of-life treatment preferences. Design, Setting, and Participants: This multisite, assessor-blinded, randomized clinical trial enrolled adolescents with cancer (aged 14-21 years) and their family members from 4 pediatric hospitals between July 16, 2016, and April 30, 2019. Participants were randomized 2:1 to FACE-TC (intervention group) or treatment as usual (control group) and underwent 5 follow-up visits over an 18-month postintervention period. Intention-to-treat analyses were conducted from March 9, 2021, to April 14, 2022. Exposures: Adolescent-family dyads randomized to the FACE-TC group received 3 weekly 60-minute sessions consisting of the discussion and/or completion of the Lyon Family-Centered Advance Care Planning Survey (session 1), Respecting Choices Next Steps pACP conversation (session 2), and Five Wishes advance directive (session 3). Dyads in the control group received treatment as usual. Both groups received pACP information. Main Outcomes and Measures: Congruence was measured by completion of the Statement of Treatment Preferences (a document that discusses 4 hypothetical clinical situations and treatment choices for each scenario: continue all treatments, stop all efforts to keep me alive, or unsure) after session 2 (time 1) and at 3 months (time 2), 6 months (time 3), 12 months (time 4), and 18 months (time 5) after intervention. The influence of FACE-TC on the trajectory of congruence over time was measured by longitudinal latent class analysis. Results: A total of 252 participants (126 adolescent-family dyads) were randomized. Adolescents (mean [SD] age, 17 [1.9] years) and family members (mean [SD] age, 46 [8.3] years) were predominantly female (72 [57%] and 104 [83%]) and White individuals (100 [79%] and 103 [82%]). There was an 83% (104 of 126) retention at the 18-month assessment. Two latent classes of congruence over time were identified: high-congruence latent class (69 of 116 [60%]) and low-congruence latent class (47 of 116 [41%]). The dyads in the FACE-TC group had a 3-fold odds of being in the high-congruence latent class (odds ratio [OR], 3.22; 95% CI, 1.09-9.57) compared with the control group. Statistically significant differences existed at 12 months (β [SE] = 1.17 [0.55]; P = .03]) but not at 18 months (OR, 2.08; 95% CI, 0.92-4.69). In the high-congruence latent class, good agreement (agreement on 2 or 3 of 4 situations) increased over 12 months. White adolescents and families had significantly greater odds of congruence than a small population of American Indian or Alaska Native, Asian, Black or African American, Hispanic or Latino, or multiracial adolescents and families (OR, 3.97; 95% CI, 1.07-14.69). Conclusions and Relevance: Results of this trial showed that, for those who received the FACE-TC intervention, the families\u27 knowledge of their adolescents\u27 end-of-life treatment preferences was sustained for 1 year, suggesting yearly follow-up sessions. Race and ethnicity-based differences in the sustainability of this knowledge reflect a difference in the effect of the intervention and require further study. Trial Registration: ClinicalTrials.gov Identifier: NCT02693665