Expression of heterologous proteins flanked by NS3-4A cleavage sites within the hepatitis C virus polyprotein

AbstractHepatitis C virus (HCV) contributes substantially to human morbidity and mortality world-wide. The development of HCV genomes expressing heterologous proteins has enhanced the ability to study viral infection, but existing systems have drawbacks. Recombinant viruses often require adaptive mutations to compensate for reduced viral titers, or rely on an artificial genomic organization that uncouples viral protein expression from recombinant gene expression. Here, we sought to exploit the viral polyprotein processing machinery to express heterologous proteins within the context of the HCV polyprotein. We show that HCV genotypes 2a and 1b permit insertion of reporter proteins between NS5A and NS5B with minimal impact on viral fitness. Using this strategy we constructed reporter genomes exhibiting a wide dynamic range, simplifying analysis of HCV infection in primary hepatocytes. Expression of heterologous proteins within the HCV genome offers new opportunities to analyze HCV infection in experimental systems without perturbing functions of individual viral proteins

Recapitulation of the hepatitis C virus life-cycle in engineered murine cell lines

AbstractHepatitis C virus (HCV) remains a major medical problem. In-depth study of HCV pathogenesis and immune responses is hampered by the lack of suitable small animal models. The narrow host range of HCV remains incompletely understood. We demonstrate that the entire HCV life-cycle can be recapitulated in mouse cells. We show that antiviral signaling interferes with HCV RNA replication in mouse cells. We were able to infect mouse cells expressing human CD81 and occludin (OCLN)—the minimal set of entry factor factors required for HCV uptake into mouse cells. Infected mouse cells sustain HCV RNA replication in the presence of miR122 and release infectious particles when mouse apoE is supplied. Our data demonstrate that the barriers of HCV interspecies transmission can be overcome by engineering a suitable cellular environment and provide a blue-print towards constructing a small animal model for HCV infection

A mouse model for HIV-1 entry

Passive transfer of neutralizing antibodies against HIV-1 can prevent infection in macaques and seems to delay HIV-1 rebound in humans. Anti-HIV antibodies are therefore of great interest for vaccine design. However, the basis for their in vivo activity has been difficult to evaluate systematically because of a paucity of small animal models for HIV infection. Here we report a genetically humanized mouse model that incorporates a luciferase reporter for rapid quantitation of HIV entry. An antibody’s ability to block viral entry in this in vivo model is a function of its bioavailability, direct neutralizing activity, and effector functions

Broadly neutralizing antibodies abrogate established hepatitis C virus infection

In most exposed individuals, hepatitis C virus (HCV) establishes a chronic infection; this long-term infection in turn contributes to the development of liver diseases such as cirrhosis and hepatocellular carcinoma. The role of antibodies directed against HCV in disease progression is poorly understood. Neutralizing antibodies (nAbs) can prevent HCV infection in vitro and in animal models. However, the effects of nAbs on an established HCV infection are unclear. We demonstrate that three broadly nAbs—AR3A, AR3B, and AR4A—delivered with adeno-associated viral vectors can confer protection against viral challenge in humanized mice. Furthermore, we provide evidence that nAbs can abrogate an ongoing HCV infection in primary hepatocyte cultures and in a human liver chimeric mouse model. These results showcase a therapeutic approach to interfere with HCV infection by exploiting a previously unappreciated need for HCV to continuously infect new hepatocytes to sustain a chronic infection

How do parents experience being asked to enter a child in a randomised controlled trial?

<p>Abstract</p> <p>Background</p> <p>As the number of randomised controlled trials of medicines for children increases, it becomes progressively more important to understand the experiences of parents who are asked to enrol their child in a trial. This paper presents a narrative review of research evidence on parents' experiences of trial recruitment focussing on qualitative research, which allows them to articulate their views in their own words.</p> <p>Discussion</p> <p>Parents want to do their best for their children, and socially and legally their role is to care for and protect them yet the complexities of the medical and research context can challenge their fulfilment of this role. Parents are simultaneously responsible for their child and cherish this role yet they are dependent on others when their child becomes sick. They are keen to exercise responsibility for deciding to enter a child in a trial yet can be fearful of making the 'wrong' decision. They make judgements about the threat of the child's condition as well as the risks of the trial yet their interpretations often differ from those of medical and research experts. Individual pants will experience these and other complexities to a greater or lesser degree depending on their personal experiences and values, the medical situation of their child and the nature of the trial. Interactions at the time of trial recruitment offer scope for negotiating these complexities if practitioners have the flexibility to tailor discussions to the needs and situation of individual parents. In this way, parents may be helped to retain a sense that they have acted as good parents to their child whatever decision they make.</p> <p>Summary</p> <p>Discussing randomised controlled trials and gaining and providing informed consent is challenging. The unique position of parents in giving proxy consent for their child adds to this challenge. Recognition of the complexities parents face in making decisions about trials suggests lines for future research on the conduct of trials, and ultimately, may help improve the experience of trial recruitment for all parties.</p

Implementation costs of hospital-based computerised decision support systems : a systematic review

BACKGROUND: The importance of accurately costing implementation strategies is increasingly recognised within the field of implementation science. However, there is a lack of methodological guidance for costing implementation, particularly within digital health settings. This study reports on a systematic review of costing analyses conducted alongside implementation of hospital-based computerised decision support systems.METHODS: PubMed, Embase, Scopus and CINAHL databases were searched between January 2010 and August 2021. Two reviewers independently screened and selected original research studies that were conducted in a hospital setting, examined the implementation of a computerised decision support systems and reported implementation costs. The Expert Recommendations for Implementing Change Framework was used to identify and categorise implementation strategies into clusters. A previously published costing framework was applied to describe the methods used to measure and value implementation costs. The reporting quality of included studies was assessed using the Consolidated Health Economic Evaluation Reporting Standards checklist.RESULTS: Titles and abstracts of 1836 articles were screened, with nine articles eligible for inclusion in the review. Implementation costs were most frequently reported under the 'evaluative and iterative strategies' cluster, followed by 'provide interactive assistance'. Labour was the largest implementation-related cost in the included papers, irrespective of implementation strategy. Other reported costs included consumables, durable assets and physical space, which was mostly associated with stakeholder training. The methods used to cost implementation were often unclear. There was variation across studies in the overall quality of reporting.CONCLUSIONS: A relatively small number of papers have described computerised decision support systems implementation costs, and the methods used to measure and value these costs were not well reported. Priorities for future research should include establishing consistent terminology and appropriate methods for estimating and reporting on implementation costs.TRIAL REGISTRATION: The review protocol is registered with PROSPERO (ID: CRD42021272948).</p

Ambulatory oxygen: why do COPD patients not use their portable systems as prescribed? A qualitative study

Background: patients with COPD on long term oxygen therapy frequently do not adhere to their prescription, and they frequently do not use their ambulatory oxygen systems as intended. Reasons for this lack of adherence are not known. The aim of this study was to obtain in-depth information about perceptions and use of prescribed ambulatory oxygen systems from patients with COPD to inform ambulatory oxygen design, prescription and management.Methods: a qualitative design was used, involving semi-structured face-to-face interviews informed by a grounded theory approach. Twenty-seven UK community-dwelling COPD patients using NHS prescribed ambulatory systems were recruited. Ambulatory oxygen systems comprised cylinders weighing 3.4 kg, a shoulder bag and nasal cannulae.Results: participants reported that they: received no instruction on how to use ambulatory oxygen; were uncertain of the benefits; were afraid the system would run out while they were using it (due to lack of confidence in the cylinder gauge); were embarrassed at being seen with the system in public; and were unable to carry the system because of the cylinder weight. The essential role of carers was also highlighted, as participants with no immediate carers did not use ambulatory oxygen outside the house.Conclusions: these participants highlighted previously unreported problems that prevented them from using ambulatory oxygen as prescribed. Our novel findings point to: concerns with the lack of specific information provision; the perceived unreliability of the oxygen system; important carer issues surrounding managing and using ambulatory oxygen equipment. All of these issues, as well as previously reported problems with system weight and patient embarrassment, should be addressed to improve adherence to ambulatory oxygen prescription and enhance the physical and social benefits of maintaining mobility in this patient group. Increased user involvement in both system development and service provision planning, could have avoided many of the difficulties highlighted by this stud

Identifying barriers and facilitators to successful implementation of computerized clinical decision support systems in hospitals: a NASSS framework-informed scoping review

Abstract Background Successful implementation and utilization of Computerized Clinical Decision Support Systems (CDSS) in hospitals is complex and challenging. Implementation science, and in particular the Nonadoption, Abandonment, Scale-up, Spread and Sustainability (NASSS) framework, may offer a systematic approach for identifying and addressing these challenges. This review aimed to identify, categorize, and describe barriers and facilitators to CDSS implementation in hospital settings and map them to the NASSS framework. Exploring the applicability of the NASSS framework to CDSS implementation was a secondary aim. Methods Electronic database searches were conducted (21 July 2020; updated 5 April 2022) in Ovid MEDLINE, Embase, Scopus, PyscInfo, and CINAHL. Original research studies reporting on measured or perceived barriers and/or facilitators to implementation and adoption of CDSS in hospital settings, or attitudes of healthcare professionals towards CDSS were included. Articles with a primary focus on CDSS development were excluded. No language or date restrictions were applied. We used qualitative content analysis to identify determinants and organize them into higher-order themes, which were then reflexively mapped to the NASSS framework. Results Forty-four publications were included. These comprised a range of study designs, geographic locations, participants, technology types, CDSS functions, and clinical contexts of implementation. A total of 227 individual barriers and 130 individual facilitators were identified across the included studies. The most commonly reported influences on implementation were fit of CDSS with workflows (19 studies), the usefulness of the CDSS output in practice (17 studies), CDSS technical dependencies and design (16 studies), trust of users in the CDSS input data and evidence base (15 studies), and the contextual fit of the CDSS with the user’s role or clinical setting (14 studies). Most determinants could be appropriately categorized into domains of the NASSS framework with barriers and facilitators in the “Technology,” “Organization,” and “Adopters” domains most frequently reported. No determinants were assigned to the “Embedding and Adaptation Over Time” domain. Conclusions This review identified the most common determinants which could be targeted for modification to either remove barriers or facilitate the adoption and use of CDSS within hospitals. Greater adoption of implementation theory should be encouraged to support CDSS implementation