Self-Assembly-Assisted Kinetically Controlled Papain-Catalyzed Formation of mPEG-b-Phe(Leu)x.

Self-assembling peptide materials are promising next-generation materials with applications that include tissue engineering scaffolds, drug delivery, bionanomedicine, and enviro-responsive materials. Despite these advances, synthetic methods to form peptides and peptide-polymer conjugates still largely rely on solid-phase peptide synthesis (SPPS) and N-carboxyanhydride ring-opening polymerization (NCA-ROP), while green methods remain largely undeveloped. This work demonstrates a protease-catalyzed peptide synthesis (PCPS) capable of directly grafting leucine ethyl ester (Leu-OEt) from the C-terminus of a methoxy poly(ethylene glycol)-phenylalanine ethyl ester macroinitiator in a one-pot, aqueous reaction. By using the natural tendency of the growing hydrophobic peptide segment to self-assemble, a large narrowing of the (Leu)x distributions for both mPEG45-b-Phe(Leu)x and oligo(Leu)x coproducts, relative to oligo(Leu)x synthesized in the absence of a macroinitiator (mPEG45-Phe-OEt), was achieved. A mechanism is described where in situ ß-sheet coassembly of mPEG45-b-Phe(Leu)x and oligo(Leu)x coproducts during polymerization prevents peptide hydrolysis, providing a means to control the degree of polymerization (DP) and dispersity of diblock (Leu)x segments (matrix-assisted laser desorption time-of-flight (MALDI-TOF) x = 5.1, dispersity ≤ 1.02). The use of self-assembly to control the uniformity of peptides synthesized by PCPS paves the way for precise peptide block copolymer architectures with various polymer backbones and amino acid compositions synthesized by a green process.

Liminal Space: A Retrospective Content Analysis of Ethics Consultation for Patients Aged 18-26.

PURPOSE: To characterize the primary ethical issue and contextual features of ethics consultation for patients aged 18-26 years based on setting (adult vs. pediatric). METHODS: A retrospective review of 965 ethics consultation notes to identify patients aged 18-26 years cared for in the pediatric or adult setting between January 1, 2016-December 31, 2020. We collected demographic information and used conceptual content analysis to identify the primary ethical issue and contextual features for each consult and analyzed these using descriptive statistics. RESULTS: We identified 46 consults (30 adult and 16 pediatric) for 40 unique patients (28 adult and 12 pediatric). The median age was 19 years in the pediatric setting and 24 in the adult setting. Fifty-three percent were female, 95% non-Hispanic, 68% White, and 76% were inpatient. The primary ethical issue in the adult setting was Refusal of Recommended Treatment (20%), while the dominant contextual issue was Communication Disputes/Conflicts Between the Staff and Patient (23%). The primary ethical issue for the pediatric setting was Goals of Care (31%) and the dominant contextual feature was concerns for Quality of Life (31%). DISCUSSION: The primary ethical issues and related contextual features this population experiences differ based on setting. Improved understanding of adolescent and young adult development, especially related to values formation, decision-making, and communication skills training may ameliorate some of these challenges. Referral patterns for this age group overall and particularly for patients on the ends of the spectrum and inpatients raise concerns for ethics consultation use. Further education about ethics services is recommended.

International stem cell tourism: a critical literature review and evidence-based recommendations.

Stem cell tourism is an emerging area of medical tourism activity. Frustrated by the slow translation of stem cell research into clinical practice, patients with debilitating conditions often seek therapeutic options that are not appropriately regulated. This review summarises recent developments in the field of stem cell tourism and provides clinicians with the information necessary to provide basic pretravel health advice to stem cell tourists. PubMed and Scopus databases were consulted for relevant publications, using combinations of the terms 'stem cell', 'tourism', 'regenerative medicine', 'international', 'travel medicine' and 'environmental health'. The leading countries in the international stem cell tourism market are the USA, China, India, Thailand and Mexico. As the majority of clinics offering stem cell therapies are based in low- and-middle-income countries, stem cell tourists place themselves at risk of receiving an unproven treatment, coupled with the risk of travel-related illnesses. These clinics do not generally provide even basic travel health information on their websites. In addition to often being ineffective, stem cell therapies are associated with complications such as infection, rejection and tumorigenesis. Physicians, researchers, regulatory bodies, advocacy groups and medical educators are encouraged to work together to improve patient and physician education and address current legislative deficiencies.

Receptor tyrosine kinase (RTK) targeting in pediatric high-grade glioma and diffuse midline glioma: Pre-clinical models and precision medicine.

Pediatric high-grade glioma (pHGG), including both diffuse midline glioma (DMG) and non-midline tumors, continues to be one of the deadliest oncologic diagnoses (both henceforth referred to as "pHGG"). Targeted therapy options aimed at key oncogenic receptor tyrosine kinase (RTK) drivers using small-molecule RTK inhibitors has been extensively studied, but the absence of proper in vivo modeling that recapitulate pHGG biology has historically been a research challenge. Thankfully, there have been many recent advances in animal modeling, including Cre-inducible transgenic models, as well as intra-uterine electroporation (IUE) models, which closely recapitulate the salient features of human pHGG tumors. Over 20% of pHGG have been found in sequencing studies to have alterations in platelet derived growth factor-alpha (PDGFRA), making growth factor modeling and inhibition via targeted tyrosine kinases a rich vein of interest. With commonly found alterations in other growth factors, including FGFR, EGFR, VEGFR as well as RET, MET, and ALK, it is necessary to model those receptors, as well. Here we review the recent advances in murine modeling and precision targeting of the most important RTKs in their clinical context. We additionally provide a review of current work in the field with several small molecule RTK inhibitors used in pre-clinical or clinical settings for treatment of pHGG.