Anticoagulation Bridging in Patients With Left Ventricular Assist Device: A Regional Analysis of HeartMate 3 Recipients.

Advances in left ventricular assist device technologies have led to an improvement in pump hemocompatibility and outcomes. Because of concerns of thromboembolic complications in prior generations of left ventricular assist devices, bridging with parenteral anticoagulants was routinely. Management strategies of subtherapeutic INRs and their effects on the current generation of devices deserve review. We performed analysis of the MOMENTUM 3 trial including 6 centers in the mid-America region. Patients with subtherapeutic INRs (INR < 2) occurring after the index admission underwent chart review to determine the management strategies taken by clinicians. Strategies were divided into two groups, bridging or nonbridging. Of the 225 patients included in the analysis, 130 (58%) patients had a total of 235 subtherapeutic international normalized ratio (INR) events. Most (n = 179, 76.2%) of these INRs were not bridged (n = 100 warfarin dose adjustment, n = 79 no change in warfarin dose). Among those INRs (n = 56, 23.8%) treated with bridging, approximately half (n = 30, 53.6%) were treated with subcutaneous agents and other half (n = 26, 46.4%) were treated with intravenous agents. There was no difference in individual outcomes or composite endpoints of death, rehospitalization, CVA, or bleeding events between the groups.

The formality effect.

This paper documents the existence of a 'formality effect' in government communications. Across three online studies and three field experiments in different policy contexts (total N = 67,632), we show that, contrary to researcher and practitioner predictions, formal government communications are more effective at influencing resident behaviour than informal government communications. In exploring mechanisms, we show that formality operates as a heuristic for credibility and importance. Recipients view the source of a formal letter as more competent and trustworthy, and view the request itself as more important to take action on, despite no evidence of change in comprehension or in perceived ease of taking action. These findings have immediate implications for government communicators and open the door for a renewed focus on how the design and presentation of information impacts behaviour.

Cost-effectiveness analysis of human-centred design for global health interventions: a quantitative framework.

INTRODUCTION: Human-centred design (HCD) is a problem-solving approach that is increasingly used to develop new global health interventions. However, there is often a large initial cost associated with HCD, and global health decision-makers would benefit from an improved understanding of the cost-effectiveness of HCD, particularly the trade-offs between the up-front costs of design and the long-term costs of delivering health interventions. METHODS: We developed a quantitative framework from a health systems perspective to illustrate the conditions under which HCD-informed interventions are likely to be cost-effective, taking into consideration five elements: cost of HCD, per-client intervention cost, anticipated number of clients reached, anticipated incremental per-client health benefit (ie, disability-adjusted life years (DALYs) averted) and willingness-to-pay. We evaluated several combinations of fixed and implementation cost scenarios based on the estimated costs of an HCD-informed approach to tuberculosis (TB) contact investigation in Uganda over a 2-year period to illustrate the use of this framework. RESULTS: The cost-effectiveness of HCD-informed TB contact investigation in Uganda was estimated to vary from US$8400 (2400 clients reached, lower HCD cost estimate) to US$306 000 per DALY averted (120 clients reached, baseline HCD cost estimate). In our model, cost-effectiveness was improved further when the interventions were expected to have wider reach or higher per-client health benefits. CONCLUSION: HCD can be cost-effective when used to inform interventions that are anticipated to reach a large number of clients, or in which the cost of HCD is smaller relative to the cost of delivering the intervention itself.

Enhancing Human-Centered Design With Youth-Led Participatory Action Research Approaches for Adolescent Sexual and Reproductive Health Programming.

Existing participatory research approaches have failed to identify innovative methods that overcome the persistent barriers to adolescent sexual and reproductive health service demand and access. Increasingly, programmers have turned to human-centered design (HCD), a problem-solving process that centers the needs, perspectives, and experiences of people, when developing solutions to complex SRH challenges. This article describes the application of a youth-engaged version of HCD as part of Adolescents 360, a transdisciplinary initiative to increase 15- to 19-year-old girls' use of modern contraception in Nigeria, Ethiopia, and Tanzania. Youth-adult design teams (including 111 "youth designers" trained in HCD methods) undertook formative research to inform the design and implementation of interventions. We reflect on the practical implications of using instrumental strategies of HCD with a youth-led participatory approach. Our experience indicates that (1) engaging youth as project partners in transdisciplinary teams requires planned and dedicated financial and human resources; (2) involving youth as action researchers can help identify opportunities to improve program empathy and responsiveness; (3) it is difficult to recruit "extreme users" as project partners because of the high competencies needed in HCD; (4) centering empathy and employing design standards during prototyping can drive decision-making and resolve questions raised by conflicting evidence claims in existing bodies of literature; and (5) testing tangible services and products in real-world settings continues long after the intervention design phase. Youth-adult partnership should continue throughout this iterative and adaptive phase to ensure that the adolescent experience of the intervention remains at the core of intervention delivery.

Use of Mobile Clinical Decision Support Software by Junior Doctors at a UK Teaching Hospital: Identification and Evaluation of Barriers to Engagement.

BACKGROUND: Clinical decision support (CDS) tools improve clinical diagnostic decision making and patient safety. The availability of CDS to health care professionals has grown in line with the increased prevalence of apps and smart mobile devices. Despite these benefits, patients may have safety concerns about the use of mobile devices around medical equipment. OBJECTIVE: This research explored the engagement of junior doctors (JDs) with CDS and the perceptions of patients about their use. There were three objectives for this research: (1) to measure the actual usage of CDS tools on mobile devices (mCDS) by JDs, (2) to explore the perceptions of JDs about the drivers and barriers to using mCDS, and (3) to explore the perceptions of patients about the use of mCDS. METHODS: This study used a mixed-methods approach to study the engagement of JDs with CDS accessed through mobile devices. Usage data were collected on the number of interactions by JDs with mCDS. The perceived drivers and barriers for JDs to using CDS were then explored by interviews. Finally, these findings were contrasted with the perception of patients about the use of mCDS by JDs. RESULTS: Nine of the 16 JDs made a total of 142 recorded interactions with the mCDS over a 4-month period. Only 27 of the 114 interactions (24%) that could be categorized as on-shift or off-shift occurred on-shift. Eight individual, institutional, and cultural barriers to engagement emerged from interviews with the user group. In contrast to reported cautions and concerns about the impact of clinicians' use of mobile phone on patient health and safety, patients had positive perceptions about the use of mCDS. CONCLUSIONS: Patients reported positive perceptions toward mCDS. The usage of mCDS to support clinical decision making was considered to be positive as part of everyday clinical practice. The degree of engagement was found to be limited due to a number of individual, institutional, and cultural barriers. The majority of mCDS engagement occurred outside of the workplace. Further research is required to verify these findings and assess their implications for future policy and practice.

An intrastrand three-DNA-base interaction is a key specificity determinant of F transfer initiation and of F TraI relaxase DNA recognition and cleavage.

Bacterial conjugation, transfer of a single conjugative plasmid strand between bacteria, diversifies prokaryotic genomes and disseminates antibiotic resistance genes. As a prerequisite for transfer, plasmid-encoded relaxases bind to and cleave the transferred plasmid strand with sequence specificity. The crystal structure of the F TraI relaxase domain with bound single-stranded DNA suggests binding specificity is partly determined by an intrastrand three-way base-pairing interaction. We showed previously that single substitutions for the three interacting bases could significantly reduce binding. Here we examine the effect of single and double base substitutions at these positions on plasmid mobilization. Many substitutions reduce transfer, although the detrimental effects of some substitutions can be partially overcome by substitutions at a second site. We measured the affinity of the F TraI relaxase domain for several DNA sequence variants. While reduced transfer generally correlates with reduced binding affinity, some oriT variants transfer with an efficiency different than expected from their binding affinities, indicating ssDNA binding and cleavage do not correlate absolutely. Oligonucleotide cleavage assay results suggest the essential function of the three-base interaction may be to position the scissile phosphate for cleavage, rather than to directly contribute to binding affinity.

Using fluorophore-labeled oligonucleotides to measure affinities of protein-DNA interactions.

Changes in fluorescence emission intensity and anisotropy can reflect changes in the environment and molecular motion of a fluorophore. Researchers can capitalize on these characteristics to assess the affinity and specificity of DNA-binding proteins using fluorophore-labeled oligonucleotides. While there are many advantages to measuring binding using fluorescent oligonucleotides, there are also some distinct disadvantages. Here we describe some of the relevant issues for the novice, illustrating key points using data collected with a variety of labeled oligonucleotides and the relaxase domain of F plasmid TraI. Topics include selection of a fluorophore, experimental design using a fluorometer equipped with an automatic titrating unit, and analysis of direct binding and competition assays.

Inter- and intramolecular determinants of the specificity of single-stranded DNA binding and cleavage by the F factor relaxase.

The TraI protein of conjugative plasmid F factor binds and cleaves a single-stranded region of the plasmid prior to transfer to a recipient. TraI36, an N-terminal TraI fragment, binds ssDNA with a subnanomolar K(D) and remarkable sequence specificity. The structure of the TraI36 Y16F variant bound to ssDNA reveals specificity determinants, including a ssDNA intramolecular 3 base interaction and two pockets within the protein's binding cleft that accommodate bases in a knob-into-hole fashion. Mutagenesis results underscore the intricate design of the binding site, with the greatest effects resulting from substitutions for residues that both contact ssDNA and stabilize protein structure. The active site architecture suggests that the bound divalent cation, which is essential for catalysis, both positions the DNA by liganding two oxygens of the scissile phosphate and increases the partial positive charge on the phosphorus to enhance nucleophilic attack.

Structural insights into single-stranded DNA binding and cleavage by F factor TraI.

Conjugative plasmid transfer between bacteria disseminates antibiotic resistance and diversifies prokaryotic genomes. Relaxases, proteins essential for conjugation, cleave one plasmid strand sequence specifically prior to transfer. Cleavage occurs through a Mg(2+)-dependent transesterification involving a tyrosyl hydroxyl and a DNA phosphate. The structure of the F plasmid TraI relaxase domain, described here, is a five-strand beta sheet flanked by alpha helices. The protein resembles replication initiator protein AAV-5 Rep but is circularly permuted, yielding a different topology. The beta sheet forms a binding cleft lined with neutral, nonaromatic residues, unlike most single-stranded DNA binding proteins which use aromatic and charged residues. The cleft contains depressions, suggesting base recognition occurs in a knob-into-hole fashion. Unlike most nucleases, three histidines but no acidic residues coordinate a Mg(2+) located near the catalytic tyrosine. The full positive charge on the Mg(2+) and the architecture of the active site suggest multiple roles for Mg(2+) in DNA cleavage.

Crystallization and preliminary X-ray characterization of the relaxase domain of F factor TraI.

Conjugative plasmids are capable of transferring a copy of themselves in single-stranded form from donor to recipient bacteria. Prior to transfer, one plasmid strand must be cleaved in a sequence-specific manner by a relaxase or mobilization protein. TraI is the relaxase for the conjugative plasmid F factor. A 36 kDa N-terminal fragment of TraI possesses the single-stranded DNA-binding and cleavage activity of the protein. Crystals of the 36 kDa TraI fragment in native and selenomethionine-labeled forms were grown by sitting-drop vapor-diffusion methods using PEG 1000 as the precipitant. Crystallization in the presence of chloride salts of magnesium and strontium was required to obtain crystals yielding high-resolution diffraction. To maintain high-resolution diffraction upon freezing, crystals had to be soaked in crystallization buffer with stepwise increases of ethylene glycol. The resulting crystals were trigonal and diffracted to a resolution of 3.1 A or better using synchrotron radiation.

Subdomain organization and catalytic residues of the F factor TraI relaxase domain.

TraI from conjugative plasmid F factor is both a "relaxase" that sequence-specifically binds and cleaves single-stranded DNA (ssDNA) and a helicase that unwinds the plasmid during transfer. Using limited proteolysis of a TraI fragment, we generated a 36-kDa fragment (TraI36) retaining TraI ssDNA binding specificity and relaxase activity but lacking the ssDNA-dependent ATPase activity of the helicase. Further proteolytic digestion of TraI36 generates stable N-terminal 26-kDa (TraI26) and C-terminal 7-kDa fragments. Both TraI36 and TraI26 are stably folded and unfold in a highly cooperative manner, but TraI26 lacks affinity for ssDNA. Mutational analysis of TraI36 indicates that N-terminal residues Tyr(16) and Tyr(17) are required for efficient ssDNA cleavage but not for high-affinity ssDNA binding. Although the TraI36 N-terminus provides the relaxase catalytic residues, both N- and C-terminal structural domains participate in binding, suggesting that both domains combine to form the TraI relaxase active site.