Synthesis of Membrane-Permeable Macrocyclic Peptides via Imidazopyridinium Grafting.

Macrocyclic peptides (MPs) are a class of compounds that have been shown to be particularly well suited for engaging difficult protein targets. However, their utility is limited by their generally poor cell permeability and bioavailability. Here, we report an efficient solid-phase synthesis of novel MPs by trapping a reversible intramolecular imine linkage with a 2-formyl- or 2-keto-pyridine to create an imidazopyridinium (IP+)-linked ring. This chemistry is useful for the creation of macrocycles of different sizes and geometries, including head-to-side and side-to-side chain configurations. Many of the IP+-linked MPs exhibit far better passive membrane permeability than expected for "beyond Rule of 5" molecules, in some cases exceeding that of much lower molecular weight, traditional drug molecules. We demonstrate that this chemistry is suitable for the creation of libraries of IP+-linked MPs and show that these libraries can be mined for protein ligands.

Deference or critical engagement: how should healthcare practitioners use clinical ethics guidance?

Healthcare practitioners have access to a range of ethical guidance. However, the normative role of this guidance in ethical decision-making is underexplored. This paper considers two ways that healthcare practitioners could approach ethics guidance. We first outline the idea of deference to ethics guidance, showing how an attitude of deference raises three key problems: moral value; moral understanding; and moral error. Drawing on philosophical literature, we then advocate an alternative framing of ethics guidance as a form of moral testimony by colleagues and suggest that a more promising attitude to ethics guidance is to approach it in the spirit of 'critical engagement' rather than deference.

Translational or translationable? A call for ethno-immersion in (empirical) bioethics research.

The shift towards "empirical bioethics" was largely triggered by a recognition that stakeholders' views and experiences are vital in ethical analysis where one hopes to produce practicable recommendations. Such perspectives can provide a rich resource in bioethics scholarship, perhaps challenging the researcher's perspective. However, overreliance on a picture painted by a group of research participants-or on pre-existing literature in that field-can lead to a biased view of a given context, as the subjectivity of data generated in these ways cannot (and should not wholly) be escaped. In response, we propose the implementation of a complementary approach of ethno-immersion in bioethics research. By positioning oneself in the context being researched, the researcher can better understand the realities of that context. The researcher's understanding will, naturally, be subjective too. However, it will act as a better developed and more informed outsider view, when considering the picture painted by participants and previous studies, thus enabling the researcher to introduce more nuance when analysing data. We introduce this approach after examining what we call the context detachment problem, whereby some bioethics scholarship-empirical or otherwise-fails to reflect the reality of the healthcare setting it concerns. Our proposed ethno-immersion (which differs from formal ethnography) is then explored as a response, highlighting its benefits, and answering the question of timing within a research project. Finally, we reflect on the applicability of our proposal to non-empirical bioethics scholarship, concluding that it remains important but may require some adjustments.

How should institutions help clinicians to practise greener anaesthesia: first-order and second-order responsibilities to practice sustainably.

There is a need for all industries, including healthcare, to reduce their greenhouse gas emissions. In anaesthetic practice, this not only requires a reduction in resource use and waste, but also a shift away from inhaled anaesthetic gases and towards alternatives with a lower carbon footprint. As inhalational anaesthesia produces greenhouse gas emissions at the point of use, achieving sustainable anaesthetic practice involves individual practitioner behaviour change. However, changing the practice of healthcare professionals raises potential ethical issues. The purpose of this paper is twofold. First, we discuss what moral duties anaesthetic practitioners have when it comes to practices that impact the environment. We argue that behaviour change among practitioners to align with certain moral responsibilities must be supplemented with an account of institutional duties to support this. In other words, we argue that institutions and those in power have second-order responsibilities to ensure that practitioners can fulfil their first-order responsibilities to practice more sustainably. The second goal of the paper is to consider not just the nature of second-order responsibilities but the content. We assess four different ways that second-order responsibilities might be fulfilled within healthcare systems: removing certain anaesthetic agents, seeking consensus, education and methods from behavioural economics. We argue that, while each of these are a necessary part of the picture, some interventions like nudges have considerable advantages.

A Rare Case of Constrictive Pericarditis: Inflammatory Myofibroblastic Tumor.

A previously healthy 15-year-old adolescent female presented with dependent edema, ascites, and dyspnea on exertion. The result of her initial evaluation was consistent with constrictive pericarditis in the setting of local low-grade spindle cell sarcoma. She was unresponsive to traditional medical management and required concurrent mass resection and radical pericardiectomy for definitive treatment. (Level of Difficulty: Intermediate.).

Ischemic or Coronary Evaluations in Patients With Monomorphic VT Electrical Storm Undergoing VT Ablation.

BACKGROUND: Monomorphic ventricular tachycardia (VT) electrical storm (ES) in patients with coronary artery disease is dependent on scarred myocardium. The role of routine ischemic or coronary evaluations before ablation in patients presenting with monomorphic VT storm, without acute coronary syndrome (ACS), remains unknown. OBJECTIVES: This study sought to assess the impact of ischemic or coronary evaluations on procedural outcomes and post-ablation mortality in monomorphic VT storm patients. METHODS: All patients undergoing VT ablation at the Cleveland Clinic from 2014 to 2020 after presenting with monomorphic VT storm were enrolled in a prospectively maintained registry. The associations among ischemic or coronary evaluations and short-term procedural efficacy, acute outcomes, and mortality during follow-up were assessed. RESULTS: A total of 97 consecutive patients with monomorphic VT storm in the absence of ACS underwent VT ablations. This cohort was characterized by severe LV systolic dysfunction (mean left ventricular ejection fraction 30.3%, 67% with known ischemic cardiomyopathy) with moderately severe heart failure (median NYHA functional class II); 45% of patients underwent ischemic or coronary evaluations via coronary angiography (10%), noninvasive myocardial perfusion (26%), or both (9%). The yield of these evaluations was low: No acute coronary occlusions were identified. There was no association between ischemic evaluation and acute ablation outcomes or mortality during follow-up. Similarly, in a secondary analysis, the yield of ischemic or coronary evaluations in patients with monomorphic VT storm and known coronary disease (regardless of ablation status) was found to be low. CONCLUSIONS: Ischemic evaluations in patients with monomorphic VT storm without ACS may not improve procedural outcomes or mortality after ablation.

The best of both worlds? Rattlesnake hybrid zones generate complex combinations of divergent venom phenotypes that retain high toxicity.

Studying the consequences of hybridization between closely related species with divergent traits can reveal patterns of evolution that shape and maintain extreme trophic adaptations. Snake venoms are an excellent model system for examining the evolutionary and ecological patterns that underlie highly selected polymorphic traits. Here we investigate hybrid venom phenotypes that result from natural introgression between two rattlesnake species that express highly divergent venom phenotypes: Crotalus o. concolor and C. v. viridis. Though not yet documented, interbreeding between these species may lead to novel venom phenotypes with unique activities that break the typical trends of venom composition in rattlesnakes. The characteristics of these unusual phenotypes could unveil the roles of introgression in maintaining patterns of venom composition and variation, including the near ubiquitous dichotomy between neurotoxic or degradative venoms observed across rattlesnakes. We use RADseq data to infer patterns of gene flow and hybrid ancestry between these diverged lineages and link these genetic data with analyses of venom composition, biological activity, and whole animal model toxicity tests to understand the impacts of introgression on venom composition. We find that introgressed populations express admixed venom phenotypes that do not sacrifice biological activity (lethal toxicity) or overall abundance of dominant toxins compared to parental venoms. These hybridized venoms therefore do not represent a trade-off in functionality between the typical phenotypic extremes but instead represent a unique combination of characters whose expression appears limited to the hybrid zone.

Snakes on a plain: biotic and abiotic factors determine venom compositional variation in a wide-ranging generalist rattlesnake.

BACKGROUND: Snake venoms are trophic adaptations that represent an ideal model to examine the evolutionary factors that shape polymorphic traits under strong natural selection. Venom compositional variation is substantial within and among venomous snake species. However, the forces shaping this phenotypic complexity, as well as the potential integrated roles of biotic and abiotic factors, have received little attention. Here, we investigate geographic variation in venom composition in a wide-ranging rattlesnake (Crotalus viridis viridis) and contextualize this variation by investigating dietary, phylogenetic, and environmental variables that covary with venom. RESULTS: Using shotgun proteomics, venom biochemical profiling, and lethality assays, we identify 2 distinct divergent phenotypes that characterize major axes of venom variation in this species: a myotoxin-rich phenotype and a snake venom metalloprotease (SVMP)-rich phenotype. We find that dietary availability and temperature-related abiotic factors are correlated with geographic trends in venom composition. CONCLUSIONS: Our findings highlight the potential for snake venoms to vary extensively within species, for this variation to be driven by biotic and abiotic factors, and for the importance of integrating biotic and abiotic variation for understanding complex trait evolution. Links between venom variation and variation in biotic and abiotic factors indicate that venom variation likely results from substantial geographic variation in selection regimes that determine the efficacy of venom phenotypes across populations and snake species. Our results highlight the cascading influence of abiotic factors on biotic factors that ultimately shape venom phenotype, providing evidence for a central role of local selection as a key driver of venom variation.

Large Left Ventricular Pseudoaneurysm Presenting as an Embolic Stroke After a "Silent" Myocardial Infarction.

A 72-year-old woman with no history of coronary artery disease presented with an acute left middle cerebral artery stroke and was found to have a large left ventricular pseudoaneurysm measuring 8.7 × 7.6 cm and 2 large left ventricular thrombi, the source of her systemic embolization. Despite initial medical management, she developed refractory New York Heart Association functional class III heart failure, uncontrolled atrial fibrillation, and further enlargement of her pseudoaneurysm to 5.5 × 10.6 × 9.2 cm. She underwent urgent aneurysmectomy. Left ventricular pseudoaneurysms are rare and most commonly occur following an acute myocardial infarction when a ventricular free-wall rupture is contained by pericardium or thrombi. Historically, left ventricular angiography displaying a lack of an overlying coronary artery was the gold standard for diagnosis. Now, noninvasive imaging such as computed tomography, magnetic resonance imaging, and echocardiogram with ultrasound-enhancing agent, are reliable diagnostic tools. They can distinguish a pseudoaneurysm from a true left ventricular aneurysm using characteristic findings such as a narrow aneurysm neck, bidirectional doppler flow between the pseudoaneurysm and the left ventricle, and abrupt changes in the cardiac wall structures. Progressive dilation, wall thinning, and dyskinesis can result in refractory heart failure, arrhythmias, and thrombi formation from venous stasis. Pseudoaneurysms have a 30% to 45% risk of rupture and can be treated with left ventricular aneurysmectomy.

Barriers to green inhaler prescribing: ethical issues in environmentally sustainable clinical practice.

The National Health Service (NHS) was the first healthcare system globally to declare ambitions to become net carbon zero. To achieve this, a shift away from metered-dose inhalers which contain powerful greenhouse gases is necessary. Many patients can use dry powder inhalers which do not contain greenhouse gases and are equally effective at managing respiratory disease. This paper discusses the ethical issues that arise as the NHS attempts to mitigate climate change. Two ethical issues that pose a barrier to moving away from metered-dose inhalers are considered: patients who decline an inhaler with a smaller carbon footprint and increased cost. I argue that while a patient is not morally justified in refusing a more environmentally sustainable inhaler due to the expected harms, a doctor may still prescribe a metered-dose inhaler if they believe that switching without consent might undermine trust or substantially worsen the patient's health. Turning to cost, I argue that the imperative to combat climate change means the NHS should accept small increased financial costs for lower carbon inhalers, even though this provides no additional direct benefit for the patient. I then go on to consider the implications of the preceding analysis for policy and practice. I argue for a policy that minimises the impact of inhalers on the climate by advocating for a principle of environmental prescribing and explore decision-making in practice. While the arguments here pertain primarily to inhalers, the discussion has broader implications for debates around healthcare's responsibility to be environmentally sustainable.

Evidence that genomic incompatibilities and other multilocus processes impact hybrid fitness in a rattlesnake hybrid zone.

Hybrid zones provide valuable opportunities to understand the genomic mechanisms that promote speciation by providing insight into factors involved in intermediate stages of speciation. Here, we investigate introgression in a hybrid zone between two rattlesnake species (Crotalus viridis and Crotalus oreganus concolor) that have undergone historical allopatric divergence and recent range expansion and secondary contact. We use Bayesian genomic cline models to characterize genomic patterns of introgression between these lineages and identify loci potentially subject to selection in hybrids. We find evidence for a large number of genomic regions with biased ancestry that deviate from the genomic background in hybrids (i.e., excess ancestry loci), which tend to be associated with genomic regions with higher recombination rates. We also identify suites of excess ancestry loci that show highly correlated allele frequencies (including conspecific and heterospecific combinations) across physically unlinked genomic regions in hybrids. Our findings provide evidence for multiple multilocus evolutionary processes impacting hybrid fitness in this system.

Predictors and outcome of electrical storm-induced cardiogenic shock.

AIM: Limited information is available about the short- and long-term outcomes in electrical storm (ES)-induced cardiogenic shock (CS) and its predictors. METHODS AND RESULTS: This is a retrospective, single-centre cohort study of consecutive patients with ES admitted to the Cardiac Intensive Care Unit between 2015 and 2020. The proportion of ES patients who developed CS was adjudicated, and clinical predictors of in-hospital ventricular arrhythmia (VA)-related mortality and 1-year all-cause mortality were investigated. Of the 214 patients with ES, 33.6% developed CS. Left-ventricular ejection fraction, admission lactate, absence of an implantable cardioverter defibrillator, and admission central venous pressure were independently associated with development of CS (P < 0.03 for all). Based on these variables, a FLIC score was developed (https://riskcalc.org/FLICscore/) to predict ES-induced CS [area under the curve (AUC) = 0.949, with AUC = 0.954 in a validation cohort, both P < 0.001]. Patients who developed CS had a 11.3-fold [95% confidence interval (CI) 2.7-12.8] increased odds for in-hospital VA-related mortality and 9.4-fold (95% CI 4.0-22.4) increased odds for in-hospital all-cause mortality. A FLIC score above 0.62 was associated with a 6.2- and 5.8-fold increased odds for respectively similar endpoints. Patients with ES-induced CS received more treatment modalities to manage the ES (4.5 ± 1.8 vs. 2.3 ± 1.2, P < 0.001) and had longer length of stay [14 (8-27) vs. 8 (5-13), P < 0.001] than patients without CS. Interestingly, if patients with ES-induced CS survived to discharge, their outcomes were similar to those without CS at 1 year. CONCLUSION: Cardiogenic shock in ES is a frequent and potentially life-threatening complication with high short-term mortality. A novel risk score could identify patient at risk, generating a potential for early risk-based interventions.

The roles of balancing selection and recombination in the evolution of rattlesnake venom.

The origin of snake venom involved duplication and recruitment of non-venom genes into venom systems. Several studies have predicted that directional positive selection has governed this process. Venom composition varies substantially across snake species and venom phenotypes are locally adapted to prey, leading to coevolutionary interactions between predator and prey. Venom origins and contemporary snake venom evolution may therefore be driven by fundamentally different selection regimes, yet investigations of population-level patterns of selection have been limited. Here, we use whole-genome data from 68 rattlesnakes to test hypotheses about the factors that drive genomic diversity and differentiation in major venom gene regions. We show that selection has resulted in long-term maintenance of genetic diversity within and between species in multiple venom gene families. Our findings are inconsistent with a dominant role of directional positive selection and instead support a role of long-term balancing selection in shaping venom evolution. We also detect rapid decay of linkage disequilibrium due to high recombination rates in venom regions, suggesting that venom genes have reduced selective interference with nearby loci, including other venom paralogues. Our results provide an example of long-term balancing selection that drives trans-species polymorphism and help to explain how snake venom keeps pace with prey resistance.

Doctors as Appointed Fiduciaries: A Supplemental Model for Medical Decision-Making.

How should we respond to patients who do not wish to take on the responsibility and burdens of making decisions about their own care? In this paper, we argue that existing models of decision-making in modern healthcare are ill-equipped to cope with such patients and should be supplemented by an "appointed fiduciary" model where decision-making authority is formally transferred to a medical professional. Healthcare decisions are often complex and for patients can come at time of vulnerability. While this does not undermine their capacity, it can be excessively burdensome. Most existing models of decision-making mandate that patients with capacity must retain ultimate responsibility for decisions. An appointed fiduciary model provides a formalized mechanism through which those few patients who wish to defer responsibility can hand over decision-making authority. By providing a formal structure for deferring to an appointed fiduciary, the confusions and risks of the informal transfers that can occur in practice are avoided. Finally, we note how appropriate governance and law can provide safeguards against risks to the welfare of patients and medical professionals.

Terrible choices in the septic child: a response to the PALOH trial round table authors.

In this response article, we challenge a core assumption that lies at the centre of a round table discussion regarding the Pharmacogenetics to Avoid Loss of Hearing trial. The round table regards a genetic test for a variant (mt.1555A>G) that increases the risk of deafness if a carrier is given the antibiotic gentamicin. The idea is that rapid testing can identify neonates at risk, providing an opportunity to prevent giving an antibiotic that might cause deafness. We challenge the assumption that a positive test unequivocally guides antibiotic choice because, aside from the risk of deafness, all antibiotics for neonatal sepsis are equivalent. We argue that this assumption is faulty and has particularly troubling moral consequences. We claim that giving an alternative to gentamicin is potentially providing inferior treatment and thereby may increase the risk of death. Parents and doctors are faced with a terrible choice as a result of positive point-of-care testing (POCT): give gold-standard treatment and risk deafness or give second line care and risk death. While we do not indicate an answer to this choice, what we do argue is that such a deep and difficult choice is one that may make parents wish genetic testing was never undertaken, and therefore, contra some authors in the round table, provides a reason to gain specific consent for POCT.

No Blame No Gain? From a No Blame Culture to a Responsibility Culture in Medicine.

Healthcare systems need to consider not only how to prevent error, but how to respond to errors when they occur. In the United Kingdom's National Health Service, one strand of this latter response is the 'No Blame Culture', which draws attention from individuals and towards systems in the process of understanding an error. Defences of the No Blame Culture typically fail to distinguish between blaming someone and holding them responsible. This article argues for a 'responsibility culture', where healthcare professionals are held responsible in cases of foreseeable and avoidable errors. We demonstrate how healthcare professionals can justifiably be held responsible for their errors even though they work in challenging circumstances. We then review the idea of 'responsibility without blame', applying this to cases of error in healthcare. Sensitive to the undesirable effects of blaming healthcare professionals and to the moral significance of holding individuals accountable, we argue that a responsibility culture has significant advantages over a No Blame Culture due to its capacity to enhance patient safety and support medical professionals in learning from their mistakes, while also recognising and validating the legitimate sense of responsibility that many medical professionals feel following avoidable error, and motivating medical professionals to report errors.