Accuracy of digital impressions for implant-supported complete-arch prosthesis when using an auxiliary geometry device.

Background/purpose: Digital impressions using intraoral scanners have recently gained popularity. The aim of the present study was to evaluate the fit of full-arch screw-retained cobalt-chromium frameworks fabricated via two different digital impression methods. Materials and methods: An edentulous resin master model with four dental implants was fabricated. Forty cobalt-chromium superstructures were fabricated and evaluated according to four groups. In Group 1, the superstructures were evaluated using an intraoral scanner to generate digital impressions. Group 2 relied on the help of an auxiliary geometric appliance in generation of digital impressions via intraoral scanner. The traditional method of splinted open-tray conventional impressions was designated for Group 3. Finally, the control group (Group 4) relied on scanning of the master model directly with a laboratory scanner. Vertical marginal discrepancy was evaluated, and data obtained were statistically analyzed. Results: The highest mean vertical marginal gap value (80.86 ± 50.06 µm) was observed for Group 1 and statistically higher than Group 2, 3, and 4 (P < 0.05). The lowest mean vertical marginal gap value (41.98 ± 26.33 µm) was measured from Group 4 and statistically similar to Group 2 and 3 (P > 0.05). Conclusion: It has been suggested that the use of auxiliary geometric appliances yields increased scanning accuracy. Frameworks fabricated using the traditional splinted open-tray technique were more reliable compared to those frameworks from digital impressions.

Poor Translatability of Biomedical Research Using Animals - A Narrative Review.

The failure rate for the translation of drugs from animal testing to human treatments remains at over 92%, where it has been for the past few decades. The majority of these failures are due to unexpected toxicity - that is, safety issues revealed in human trials that were not apparent in animal tests - or lack of efficacy. However, the use of more innovative tools, such as organs-on-chips, in the preclinical pipeline for drug testing, has revealed that these tools are more able to predict unexpected safety events prior to clinical trials and so can be used for this, as well as for efficacy testing. Here, we review several disease areas, and consider how the use of animal models has failed to offer effective new treatments. We also make some suggestions as to how the more human-relevant new approach methodologies might be applied to address this.

Phase-In to Phase-Out-Targeted, Inclusive Strategies Are Needed to Enable Full Replacement of Animal Use in the European Union.

In September 2021, the European Parliament voted overwhelmingly in favour of a resolution to phase out animal use for research, testing, and education, through the adoption of an action plan. Here we explore the opportunity that the action plan could offer in developing a more holistic outlook for fundamental and biomedical research, which accounts for around 70% of all animal use for scientific purposes in the EU. We specifically focus on biomedical research to consider how mapping scientific advances to patient needs, taking into account the ambitious health policies of the EU, would facilitate the development of non-animal strategies to deliver safe and effective medicines, for example. We consider what is needed to help accelerate the move away from animal use, taking account of all stakeholders and setting ambitious but realistic targets for the total replacement of animals. Importantly, we envisage this as a 'phase-in' approach, encouraging the use of human-relevant NAMs, enabling their development and application across research (with applications for toxicology testing). We make recommendations for three pillars of activity, inspired by similar efforts for making the shift to renewable energy and reducing carbon emissions, and point out where investment-both financial and personnel-may be needed.

Patient-Derived Xenograft vs. Organoids: A Preliminary Analysis of Cancer Research Output, Funding and Human Health Impact in 2014-2019.

Cancer remains a major threat to mortality and morbidity globally, despite intense research and generous funding. Patient-derived xenograft (PDX) models-where tumor biopsies are injected into an animal-were developed to improve the predictive capacity of preclinical animal models. However, recent observations have called into question the clinical relevance, and therefore the translational accuracy, of these. Patient-derived organoids (PDO) use patient tumor samples to create in vitro models that maintain aspects of tumor structure and heterogeneity. We undertook a preliminary analysis of the number of breast, colorectal, and lung cancer research studies using PDX or PDO published worldwide between 2014-2019. We looked for evidence of impacts of this research on human health. The number of publications that focused on PDO is gradually increasing over time, but is still very low compared to publications using PDX models. Support for new research projects using PDO is gradually increasing, a promising indicator of a shift towards more human-relevant approaches to understanding human disease. Overall, increases in total funding for these three major cancer types does not appear to be translating to any consequential increase in outputs, defined for this purpose as publications associated with clinical trials. With increasing public discomfort in research using animals and demands for 'alternative' methods, it is timely to consider how to implement non-animal methods more effectively.

Anaerobiosis influences virulence properties of Pseudomonas aeruginosa cystic fibrosis isolates and the interaction with Staphylococcus aureus.

The airways of individuals with cystic fibrosis (CF) are abundantly colonised by Staphylococcus aureus and Pseudomonas aeruginosa. Co-infecting hypoxic regions of static mucus within CF airways, together with decreases in pulmonary function, mucus plugging and oxygen consumption by host neutrophils gives rise to regions of anoxia. This study determined the impact of anaerobiosis upon S. aureus-P. aeruginosa interactions in planktonic co-culture and mixed species biofilms in vitro. Whilst anoxia reduced the ability for P. aeruginosa CF isolates to dominate over S. aureus, this occurred in an isolate dependent manner. Investigations into the underlying mechanisms suggest that the anti-staphylococcal compound facilitating P. aeruginosa dominance under normoxia and anoxia is greater than 3 kDa in size and is heat-stable. Not all interspecies interactions studied were antagonistic, as S. aureus exoproducts were shown to restore and enhance P. aeruginosa motility under normoxia and anoxia in an isolate dependent manner. Collectively, this study suggests changes in oxygen availability within regions of the CF lung is likely to influence interspecies interactions and in turn, potentially influence disease progression.

Parkinson's disease research: adopting a more human perspective to accelerate advances.

Parkinson's disease (PD) affects 1% of the population over 60 years old and, with global increases in the aging population, presents huge economic and societal burdens. The etiology of PD remains unknown; most cases are idiopathic, presumed to result from genetic and environmental risk factors. Despite 200 years since the first description of PD, the mechanisms behind initiation and progression of the characteristic neurodegenerative processes are not known. Here, we review progress and limitations of the multiple PD animal models available and identify advances that could be implemented to better understand pathological processes, improve disease outcome, and reduce dependence on animal models. Lessons learned from reducing animal use in PD research could serve as guideposts for wider biomedical research.

An investigation into E-cigarette cytotoxicity in-vitro using a novel 3D differentiated co-culture model of human airways.

Currently there is a lack of consensus on the possible adverse health effects of E-cigarettes (ECs). Important factors including cell model employed and exposure method determine the physiological relevance of EC studies. The present study aimed to evaluate EC cytotoxicity using a physiologically relevant in-vitro multicellular model of human airways. Human bronchial epithelial cells (CALU-3) and pulmonary fibroblasts (MRC-5) were co-cultured at air-liquid-interface for 11-14 days post which they were exposed to whole cigarette smoke (WCS) or EC vapour (ECV) at standard ISO-3308 regime for 7 m using a bespoke aerosol delivery system. ECV effects were further investigated at higher exposure times (1 h-6 h). Results showed that while WCS significantly reduced cell viability after 7 m, ECV decreased cell viability only at exposure times higher than 3 h. Furthermore, ECV caused elevated IL-6 and IL-8 production despite reduced cell viability. ECV exposure also produced a marked increase in oxidative stress. Finally, WCS but not ECV exposure induced caspase 3/7 activation, suggesting a caspase independent death of ECV exposed cells. Overall, our results indicate that prolonged ECV exposure (≥3 h) has a significant impact on pro-inflammatory mediators' production, oxidative stress and cell viability but not caspase 3/7 activity.

Recommendations toward a human pathway-based approach to disease research.

Failures in the current paradigm for drug development have resulted in soaring research and development costs and reduced numbers of new drug approvals. Over 90% of new drug programs fail, the majority terminated at the level of Phase 2/3 clinical trials, largely because of efficacy failures or unexplained toxicity. A recent workshop brought together members from research institutions, regulatory agencies, industry, academia, and nongovernmental organizations to discuss how existing programs could be better applied to understanding human biology and improving drug discovery. Recommendations include increased emphasis on human relevance, better access and curation of data, and improved interdisciplinary and international collaboration.

Paediatric Rehabilitation Ingredients Measure: a new tool for identifying paediatric neurorehabilitation content.

AIM: To develop an instrument (Paediatric Rehabilitation Ingredients Measure [PRISM]) for quantitative estimation of contents of interdisciplinary neurorehabilitation for use in studies of relationships between rehabilitation treatment delivered and severity-adjusted outcomes after acquired brain injury (ABI). METHOD: The measure was developed using an ingredients-mediators-outcomes model consistent with the International Classification of Functioning, Disability and Health, a literature review, and other current initiatives in the development of rehabilitation treatment taxonomies, with item codevelopment in workshops with rehabilitation professionals. Interrater reliability was assessed in inpatient and residential paediatric rehabilitation settings. RESULTS: Although sometimes an initially unfamiliar perspective on rehabilitation practice, PRISM's acceptability amongst professionals was excellent. Internal consistency of scores was sometimes an issue for users unfamiliar with the tool; however, this improved with practice and interrater reliability (assessed by Kendall's W) was good. The tool was felt to have particular value in facilitating interdisciplinary communication and working. Modifications to the design of the tool have improved internal consistency. INTERPRETATION: PRISM supports identification of the 'active ingredients' of an interdisciplinary rehabilitation package and facilitates interdisciplinary communication. It also has potential as a research tool examining relationships between rehabilitation delivered and severity-adjusted outcomes observed after paediatric ABI. WHAT THIS PAPER ADDS: Identifying contribution of rehabilitation to outcomes after acquired brain injury requires quantification of rehabilitation 'dose' and 'content'. Previous approaches to 'parsing' of rehabilitation dose and content may have overemphasized one-to-one sessions with therapists. We present a novel, holistic tool for identification of ingredients of an interdisciplinary rehabilitation package. It supports interdisciplinary communication and has potential as a research tool.

A comparative study of electronic cigarette vapor extracts on airway-related cell lines in vitro.

The use of electronic cigarettes (ECs) is rapidly increasing worldwide; however, scientific evidence regarding EC cytotoxicity is limited. The aim of this study was to evaluate the acute cytotoxicity of EC vapor extract (ECE) on airway-related cells in vitro. Cigarette smoke extract (CSE), vapor extract of fifteen brands/flavors of ECs and the extract from the E-vehicle (propylene glycol and glycerin) was collected. Extracts, in concentrations of 100-12.5%, were added to human bronchial epithelial (BEAS-2B, IB3-1 and C38), fibroblast (Wi-38) and macrophage (J774 and THP-1) cell lines. Viability was assessed after 24 h using a standard XTT assay. Viability of <70% of control (no extract) was considered cytotoxic according to UNI EN ISO 10993-5 standards. CSE displayed a concentration-dependent influence on cell viability across all four cell lines with 100% producing the most toxic effect, therefore validating the model and indicating higher cytotoxicity than in ECEs. ECEs did reduce viability although this was not correlated with nicotine content or the E-vehicle. However, several flavors proved cytotoxic, with variation between different brands and cell lines. These data indicate that not all ECs are the same and that use of a particular flavor or brand may have differing effects. The cell line used is also an important factor. More research is crucial to ascertain the health effects of different ECs before they can be accepted as a safe alternative to tobacco cigarettes.

Towards a 21st-century roadmap for biomedical research and drug discovery: consensus report and recommendations.

Decades of costly failures in translating drug candidates from preclinical disease models to human therapeutic use warrant reconsideration of the priority placed on animal models in biomedical research. Following an international workshop attended by experts from academia, government institutions, research funding bodies, and the corporate and non-governmental organisation (NGO) sectors, in this consensus report, we analyse, as case studies, five disease areas with major unmet needs for new treatments. In view of the scientifically driven transition towards a human pathways-based paradigm in toxicology, a similar paradigm shift appears to be justified in biomedical research. There is a pressing need for an approach that strategically implements advanced, human biology-based models and tools to understand disease pathways at multiple biological scales. We present recommendations to help achieve this.

Minimum information about tolerogenic antigen-presenting cells (MITAP): a first step towards reproducibility and standardisation of cellular therapies.

Cellular therapies with tolerogenic antigen-presenting cells (tolAPC) show great promise for the treatment of autoimmune diseases and for the prevention of destructive immune responses after transplantation. The methodologies for generating tolAPC vary greatly between different laboratories, making it difficult to compare data from different studies; thus constituting a major hurdle for the development of standardised tolAPC therapeutic products. Here we describe an initiative by members of the tolAPC field to generate a minimum information model for tolAPC (MITAP), providing a reporting framework that will make differences and similarities between tolAPC products transparent. In this way, MITAP constitutes a first but important step towards the production of standardised and reproducible tolAPC for clinical application.

Investigation of the enhanced antimicrobial activity of combination dry powder inhaler formulations of lactoferrin.

The airways of most people with cystic fibrosis are colonized with biofilms of the Gram-negative, opportunistic pathogen Pseudomonas aeruginosa. Delivery of antibiotics directly to the lung in the form of dry powder aerosols offers the potential to achieve high local concentrations directly to the biofilms. Unfortunately, current aerosolised antibiotic regimes are unable to efficiently eradicate these biofilms from the airways. We investigated the ability of the innate antimicrobial, lactoferrin, to enhance the activity of two aminoglycoside antibiotics (tobramycin and gentamicin) against biofilms of P. aeruginosa strain PAO1. Biofilms were prepared in 96 well polystyrene plates. Combinations of the antibiotics and various lactoferrin preparations were spray dried. The bacterial cell viability of the various spray dried combinations was determined. Iron-free lactoferrin (apo lactoferrin) induced a 3-log reduction in the killing of planktonic cell by the aminoglycoside antibiotics (p<0.01) and also reduced both the formation and persistence of P. aeruginosa biofilms (p<0.01). Combinations of lactoferrin and an aminoglycoside displays potential as an effective new therapeutic strategy in the treatment of P. aeruginosa biofilms infections such as those typical of the CF lungs.

A novel regulatory role for tissue transglutaminase in epithelial-mesenchymal transition in cystic fibrosis.

Cystic fibrosis (CF) is a genetic disorder caused by mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) for which there is no overall effective treatment. Recent work indicates tissue transglutaminase (TG2) plays a pivotal intracellular role in proteostasis in CF epithelia and that the pan TG inhibitor cysteamine improves CFTR stability. Here we show TG2 has another role in CF pathology linked with TGFß1 activation and signalling, induction of epithelial-mesenchymal transition (EMT), CFTR stability and induction of matrix deposition. We show that increased TG2 expression in normal and CF bronchial epithelial cells increases TGFß1 levels, promoting EMT progression, and impairs tight junctions as measured by Transepithelial Electric Resistance (TEER) which can be reversed by selective inhibition of TG2 with an observed increase in CFTR stability. Our data indicate that selective inhibition of TG2 provides a potential therapeutic avenue for reducing fibrosis and increasing CFTR stability in CF.

Developing accurate models of the human airways.

OBJECTIVES: Particle delivery to the airways is an attractive prospect for many potential therapeutics, including vaccines. Developing strategies for inhalation of particles provides a targeted, controlled and non-invasive delivery route but, as with all novel therapeutics, in vitro and in vivo testing are needed prior to clinical use. Whilst advanced vaccine testing demands the use of animal models to address safety issues, the production of robust in vitro cellular models would take account of the ethical framework known as the 3Rs (Replacement, Reduction and Refinement of animal use), by permitting initial screening of potential candidates prior to animal use. There is thus a need for relevant, realistic in vitro models of the human airways. KEY FINDINGS: Our laboratory has designed and characterised a multi-cellular model of human airways that takes account of the conditions in the airways and recapitulates many salient features, including the epithelial barrier and mucus secretion. SUMMARY: Our human pulmonary models recreate many of the obstacles to successful pulmonary delivery of particles and therefore represent a valid test platform for screening compounds and delivery systems.

The relationship between socioeconomic status and fracture in a fracture clinic setting: data from the Nottingham Fracture Liaison Service.

BACKGROUND: This study aims to better understand the relationship between socioeconomic status (SES), fractures in those that attend an outpatient fracture clinic and a diagnosis of osteoporosis. This will further aid our ability to risk stratify patients' with fractures for further investigation and secondary management of their bone health. METHOD: This is a cross sectional analysis using data from the Nottingham Fracture Liaison Service of patients attending the outpatient fracture clinic from 1/01/08 to 31/12/11. Logistic regression adjusted for age and gender were used to investigate SES, fractures and a diagnosis of osteoporosis. Fisher's exact test was used to compare DXA attendance in those living in most deprived and least deprived area. A cut off of 65 years was used to conduct subset analysis of a younger and an older group. RESULTS: 6362 patients (1346 male, 5016 female; mean (SD) age, 69 (12)) were included in the study. There was no relationship between SES, proportion of fracture types and having a diagnosis of osteoporosis. Prevalence of osteoporosis in each SES quintile from 1 (most deprived) to 5 (least deprived) was 26.68%, 29.04%, 24.83%, 25.67% and 26.68% respectively. The least deprived quintile compared with the most deprived was not associated with a diagnosis of osteoporosis (OR 0.97; 95% CI 0.76-1.25, p=0.837). Those living in the most deprived area were less likely to attend their bone density scan appointment compared to those living in the least deprived area (OR 0.56; 95% CI 0.44-0.7, p<0.0001). CONCLUSION: This study has shown that there is no relationship between SES, fracture types and a diagnosis of osteoporosis in those that present to the fracture clinic. SES should not be used to risk stratify patients for further bone health management after fractures. Those living in the most deprived areas are less likely to attend their bone density scan and efforts need to be made to improve attendance in this group.

Sample size bias in judgments of perceptual averages.

Previous research has shown that people exhibit a sample size bias when judging the average of a set of stimuli on a single dimension. The more stimuli there are in the set, the greater people judge the average to be. This effect has been demonstrated reliably for judgments of the average likelihood that groups of people will experience negative, positive, and neutral events (Price, 2001; Price, Smith, & Lench, 2006) and also for estimates of the mean of sets of numbers (Smith & Price, 2010). The present research focuses on whether this effect is observed for judgments of average on a perceptual dimension. In 5 experiments we show that people's judgments of the average size of the squares in a set increase as the number of squares in the set increases. This effect occurs regardless of whether the squares in each set are presented simultaneously or sequentially; whether the squares in each set are different sizes or all the same size; and whether the response is a rating of size, an estimate of area, or a comparative judgment. These results are consistent with a priming account of the sample size bias, in which the sample size activates a representation of magnitude that directly biases the judgment of average.

Human aquaporins: regulators of transcellular water flow.

BACKGROUND: Emerging evidence supports the view that (AQP) aquaporin water channels are regulators of transcellular water flow. Consistent with their expression in most tissues, AQPs are associated with diverse physiological and pathophysiological processes. SCOPE OF REVIEW: AQP knockout studies suggest that the regulatory role of AQPs, rather than their action as passive channels, is their critical function. Transport through all AQPs occurs by a common passive mechanism, but their regulation and cellular distribution varies significantly depending on cell and tissue type; the role of AQPs in cell volume regulation (CVR) is particularly notable. This review examines the regulatory role of AQPs in transcellular water flow, especially in CVR. We focus on key systems of the human body, encompassing processes as diverse as urine concentration in the kidney to clearance of brain oedema. MAJOR CONCLUSIONS: AQPs are crucial for the regulation of water homeostasis, providing selective pores for the rapid movement of water across diverse cell membranes and playing regulatory roles in CVR. Gating mechanisms have been proposed for human AQPs, but have only been reported for plant and microbial AQPs. Consequently, it is likely that the distribution and abundance of AQPs in a particular membrane is the determinant of membrane water permeability and a regulator of transcellular water flow. GENERAL SIGNIFICANCE: Elucidating the mechanisms that regulate transcellular water flow will improve our understanding of the human body in health and disease. The central role of specific AQPs in regulating water homeostasis will provide routes to a range of novel therapies. This article is part of a Special Issue entitled Aquaporins.