Establishing an anatomically and clinically relevant tissue engineered tendon-bone model of the flexor digitorum profundus insertion

Avulsion of the flexor digitorum profundus (FDP) tendon from the distal phalanx (DP) in the finger is a common and distinct clinical injury of the hand (‘jersey finger’) with considerable functional morbidity. Multiple surgical techniques are employed to reattach the tendon to the bone, but no single technique has emerged as the optimal treatment method. Issues such as reduced range of movement, infection, nail deformity and cost complicate the requirement for strong fixation and prevention of re-rupture. Crucially, repair of avulsion injuries does not regenerate the enthesis, the region of graded multiphasic microanatomy at the tendon-bone insertion. The enthesis allows uniform muscle force transmission between the mechanically distinct tendon and bone through specialised adaptations to dissipate stress foci. Avulsion repair is scar-mediated and of low mechanical strength, prone to re-rupture at the tendon-bone interface. Interfacial tissue engineering provides the opportunity to create an in vitro tendon-bone model with potential to re-establish the enthesis through co-culture of tendon and bone cells, which could be used to evaluate repair techniques or as a composite tissue graft for clinical use. The aim of this project was to establish an in vitro model system that was anatomically representative and clinically applicable to the investigation and treatment of FDP avulsion injury. The 2 main objectives were to thoroughly evaluate the native anatomy of the human FDP insertion, and to design and develop a relevant 3-dimensional (3D) in vitro tendon-bone co-culture model. Human cadaveric tissue was dissected and photographed for image analysis to determine gross shape and dimension morphometrics of the FDP-DP tendon-bone interface, FDP tendon and DP bone. Finger and gender differences were found to significantly influence measurement values, with data groupings informing design guidelines for ‘small’, ‘medium’ and ‘large’ model sizes. Cadaveric tissue was also histologically processed to qualitatively describe the fibrocartilaginous FDP enthesis for the first time. Quantitative analysis of tendon fibres revealed a mean angle of insertion across the soft-hard tissue interface of 30o, providing a guide to the angled attachment of the tendon and bone model components. Development of the in vitro model enhanced an existing multi-tissue fibrin scaffold soft tissue-bone anchor design into an FDP tendon analogue-DP bone anchor single species co-culture construct. Rat fibroblast and osteoblast cultures were established and characterised in standard growth medium, mineralising medium and a 50:50 media mix. Formation and maturation of the fibroblast-seeded fibrin tendon analogue was analysed histologically in single and multi-strand cultures for morphological development and collagen deposition. Long term tendon analogues were cultured with different anchor sizes, fibrin constituent volumes, cell numbers and growth media for width comparison with cadaveric tendon data, and assessment of 3D morphology with optical coherence tomography. Investigation of the bone anchor component focused on brushite, a phosphate mineral-based bone scaffold material, including assessment of attachment and proliferation of seeded osteoblasts. Model assembly required development of a novel 3D printed mold and silicone impression system for guided tendon analogue culture and angled bone anchor attachment. Optimal design elements and in vitro culture materials ultimately combined to produce a fibroblast-seeded tendon analogue and osteoblast-seeded bone anchor 3D model, co-cultured in 3 anatomical sizes clinically relevant to FDP tendon avulsion. These models can be used as the basis to study enthesis formation and further optimised towards a clinical product for use in FDP avulsion repair

Anatomical Design and Production of a Novel 3-Dimensional Co-Culture System Replicating the Human Flexor Digitorum Profundus Enthesis

The enthesis, the specialized junction between tendon and bone, is a common site of injury. Although notoriously difficult to repair, advances in interfacial tissue engineering techniques are being developed for restorative function. Most notably are 3D in vitro co-culture models, built to recreate the complex heterogeneity of the native enthesis. While cell and matrix properties are often considered, there has been little attention given to native enthesis anatomical morphometrics and replicating these to enhance clinical relevance. This study focuses on the flexor digitorum profundus (FDP) tendon enthesis and, by combining anatomical morphometrics with computer-aided design, demonstrates the design and construction of an accurate and scalable model of the FDP enthesis. Bespoke 3D-printed mould inserts were fabricated based on the size, shape and insertion angle of the FDP enthesis. Then, silicone culture moulds were created, enabling the production of bespoke anatomical culture zones for an in vitro FDP enthesis model. The validity of the model has been confirmed using brushite cement scaffolds seeded with osteoblasts (bone) and fibrin hydrogel scaffolds seeded with fibroblasts (tendon) in individual studies with cells from either human or rat origin. This novel approach allows a bespoke anatomical design for enthesis repair and should be applied to future studies in this area.<br/

Histomorphology of the subregions of the scapholunate ligament and its enthesis

Background  The scapholunate interosseous ligament (SLIL) has three subregions: dorsal, proximal, and volar. The SLIL enthesis has not previously been studied despite its important mechanical function in wrist joint biomechanics. Questions/Purposes  This study aims to compare the histomorphological differences between the SLIL subregions, including at their entheses. Three questions are explored: Do the gross dimensions differ between SLIL subregions? Does the enthesis qualitatively, and its calcified fibrocartilage (CF) quantitatively, differ between (a) SLIL subregions and (b) scaphoid and lunate attachments? Methods  Twelve fresh-frozen human cadaveric wrists were dissected and the gross dimensions of the SLIL subregions measured. Subregions were histologically processed for morphological and compositional analyses, including quantification of enthesis CF area. Results  The dorsal subregion was the thickest. The dorsal and volar subregions had fibrocartilaginous entheses, while the proximal subregion was attached to articular cartilage. The dorsal subregion had significantly more CF than the volar subregion. There was no significant difference in the enthesis CF between scaphoid and lunate attachments in the three subregions. Conclusions  There are significant morphological differences between the SLIL subregions. The dorsal subregion has the largest amount of CF, which is consistent with the greater biomechanical force subjected to this subregion. The similar histomorphology of the ligament at the scaphoid and lunate entheses suggests that similar biomechanical forces are applied to both attachments. Clinical Relevance  The histomorphological results confirm that the dorsal subregion is the strongest of the three subregions. The results from the entheseal region may have important implications in the study of graft incorporation during SLIL reconstruction

Design and Development of a Bioreactor System for Mechanical Stimulation of Musculoskeletal Tissue

We report on the development of a bioreactor system for mechanical stimulation of musculoskeletal tissues. The ultimate object is to improve the quality of medical treatment following injuries of the enthesis tissue. To this end, the tissue formation process through the effect of mechanical stimulation is investigated. A six-well system was designed, 3D printed and tested. An integrated actuator creates strain by applying a force. A contactless position sensor monitors the travels. An electronic circuit controls the bioreactor using a microcontroller. An IoT platform connects the microcontroller to a smartphone, enabling the user to alter variables, trigger actions and monitor the system. The system was stabilised by implementing two PID controllers and safety measures. The results show that the bioreactor design is suited to execute mechanical stimulation and to investigate the tissue formation and regeneration process. The bioreactor reported here can now be implemented in tissue engineering applications including tissue specimen.</p

The Impact of Sexual Harassment on Depressive Symptoms during the Early Occupational Career

Sexual harassment has been theorized as a stressor with consequences for the physical and mental health of its targets. Although social scientists have documented a negative association between sexual harassment and mental health, few longitudinal studies have investigated the association between sexual harassment and depressive symptoms. Using longitudinal survey data from the Youth Development Study, combined with in-depth interviews, this article draws on Louise Fitzgerald’s theoretical framework, stress theory, and the life course perspective to assess the impact of sexual harassment on depressive affect during the early occupational career. In support of Fitzgerald’s model, the authors’ findings confirm that sexual harassment is a stressor that is associated with increased depressive symptoms. Quantitative results show that women and men who experience more frequent sexual harassment at work have significantly higher levels of depressed mood than harassed workers, even after controlling for prior harassment and depressive symptoms. Moreover, the authors find evidence that sexual harassment early in the career has long-term effects on depressive symptoms in adulthood. Interviews with a subset of survey respondents point to a variety of coping strategies and reveal further links between harassment and other aspects of mental health, such as anger and self-doubt

Scratch.

Scratch investigated the use of physical space as a site and representation of narrative and dramatic structure. It was commissioned by and collaboratively developed with BBC Radio Drama. Boyd Davis directed the project and devised and undertook the evaluation with 40 trial listeners. It was unprecedented in being location-sensitive without being tied to any particular place, building on research undertaken for Dragons (Boyd Davis REF Output 4). It used pre-recorded audio on GPS-enabled mobile devices allowing sounds to be virtually attached to locations in an outdoor space. As participants moved, they encountered scenes forming a coherent drama; the same place behaved differently if visited more than once. This translocational approach opened novel artistic possibilities that were exploited through team expertise in narrative, sound design and advanced interaction. It was also significant for the economics of broadcast media, a more viable proposition than the many locative experiences that have been site-specific: a factor of great interest to the BBC. The public performance selected for BBC FreeThinking, September 2008 in Liverpool, that year’s European Capital of Culture, was reported in a co-written 2009 conference presentation at ISEA, Belfast (2009) and in a co-written short chapter in Spierling and Szilas (eds.), Interactive Storytelling (2008). Boyd Davis reported the findings to BBC executives (http://researchonline.rca.ac.uk/1000/), for whom an additional trial was run in London in 2009. He used mixed methods, open but capable of rigorous analysis, to feed back to the makers of the drama and to guide BBC policy. Abigail le Fleming (Producer BBC Radio Drama) confirms that ‘through this collaboration, the Radio Drama department became the first BBC unit to experiment with GPS technologies’. The work ‘brought us to tackle non-linear narratives in ways that we would not have otherwise done… invaluable in terms of the questions that it raised for radio drama.

Generating genome browsers to facilitate undergraduate-driven collaborative genome annotation

Scientists are sequencing new genomes at an increasing rate with the goal of associating genome contents with phenotypic traits. After a new genome is sequenced and assembled, structural gene annotation is often the first step in analysis. Despite advances in computational gene prediction algorithms, most eukaryotic genomes still benefit from manual gene annotation. Undergraduates can become skilled annotators, and in the process learn both about genes/genomes and about how to utilize large datasets. Data visualizations provided by a genome browser are essential for manual gene annotation, enabling annotators to quickly evaluate multiple lines of evidence (e.g., sequence similarity, RNA-Seq, gene predictions, repeats). However, creating genome browsers requires extensive computational skills; lack of the expertise required remains a major barrier for many biomedical researchers and educators.To address these challenges, the Genomics Education Partnership (GEP; https://gep.wustl.edu/) has partnered with the Galaxy Project (https://galaxyproject.org) to develop G-OnRamp (http://g-onramp.org), a web-based platform for creating UCSC Assembly Hubs and JBrowse genome browsers. G-OnRamp can also convert a JBrowse instance into an Apollo instance for collaborative genome annotations in research and educational settings. G-OnRamp enables researchers to easily visualize their experimental results, educators to create Course-based Undergraduate Research Experiences (CUREs) centered on genome annotation, and students to participate in genomics research.Development of G-OnRamp was guided by extensive user feedback from in-person workshops. Sixty-five researchers and educators from over 40 institutions participated in these workshops, which produced over 20 genome browsers now available for research and education. For example, genome browsers for four parasitoid wasp species were used in a CURE engaging 142 students taught by 13 faculty members —producing a total of 192 gene models. G-OnRamp can be deployed on a personal computer or on cloud computing platforms, and the genome browsers produced can be transferred to the CyVerse Data Store for long-term access

Magmatic volatiles (H, C, N, F, S, Cl) in the lunar mantle, crust, and regolith: abundances, distributions, processes, and reservoirs

There have been many studies on magmatic volatiles (H, C, N, F, S, Cl) in and on the Moon within the last several years that have cast into question the post-Apollo view of lunar formation, the distribution and sources of volatiles in the Earth-Moon system, and the thermal and magmatic evolution of the Moon. However, these recent observations are not the first data on lunar volatiles. When Apollo samples were first returned, substantial efforts were made to undersand volatile elements and a wealth of data regarding volatile elements exists in this older literature. In this review paper we approach volatiles in and on the Moon using new and old data derived from lunar samples and remote sensing. From combining these data sets, we identified many points of convergence, although numerous questions remain unanswered

IMPLEmenting a clinical practice guideline for acute low back pain evidence-based manageMENT in general practice (IMPLEMENT) : cluster randomised controlled trial study protocol

Background: Evidence generated from reliable research is not frequently implemented into clinical practice. Evidence-based clinical practice guidelines are a potential vehicle to achieve this. A recent systematic review of implementation strategies of guideline dissemination concluded that there was a lack of evidence regarding effective strategies to promote the uptake of guidelines. Recommendations from this review, and other studies, have suggested the use of interventions that are theoretically based because these may be more effective than those that are not. An evidencebased clinical practice guideline for the management of acute low back pain was recently developed in Australia. This provides an opportunity to develop and test a theory-based implementation intervention for a condition which is common, has a high burden, and for which there is an evidence-practice gap in the primary care setting. Aim: This study aims to test the effectiveness of a theory-based intervention for implementing a clinical practice guideline for acute low back pain in general practice in Victoria, Australia. Specifically, our primary objectives are to establish if the intervention is effective in reducing the percentage of patients who are referred for a plain x-ray, and improving mean level of disability for patients three months post-consultation. Methods/Design: This study protocol describes the details of a cluster randomised controlled trial. Ninety-two general practices (clusters), which include at least one consenting general practitioner, will be randomised to an intervention or control arm using restricted randomisation. Patients aged 18 years or older who visit a participating practitioner for acute non-specific low back pain of less than three months duration will be eligible for inclusion. An average of twenty-five patients per general practice will be recruited, providing a total of 2,300 patient participants. General practitioners in the control arm will receive access to the guideline using the existing dissemination strategy. Practitioners in the intervention arm will be invited to participate in facilitated face-to-face workshops that have been underpinned by behavioural theory. Investigators (not involved in the delivery of the intervention), patients, outcome assessors and the study statistician will be blinded to group allocation. Trial registration: Australian New Zealand Clinical Trials Registry ACTRN012606000098538 (date registered 14/03/2006).The trial is funded by the NHMRC by way of a Primary Health Care Project Grant (334060). JF has 50% of her time funded by the Chief Scientist Office3/2006). of the Scottish Government Health Directorate and 50% by the University of Aberdeen. PK is supported by a NHMRC Health Professional Fellowship (384366) and RB by a NHMRC Practitioner Fellowship (334010). JG holds a Canada Research Chair in Health Knowledge Transfer and Uptake. All other authors are funded by their own institutions