An Innovative Method for Plantar Plate Repair: Technique Guide and Case Report.

Disruption of the plantar plate is a common cause of forefoot pain, metatarsalgia, and metatarsophalangeal joint malalignment. Although surgical repair of the plantar plate has improved, there has been no consensus on the clinical superiority of any single technique, or combination of techniques, described in the literature to date. In this publication, we report a case of plantar plate injury treated with an innovative new technique with 20-month follow-up.

Safe Placement of Intramedullary Nail and Inter-Physician Variability in Guidewire Placement in Retrograde Tibiotalocalcaneal Fusions.

Retrograde tibiotalocalcaneal arthrodesis is a salvage procedure for severe arthrosis and deformity of both the tibiotalar and subtalar joints and requires image-confirmed placement of a retrograde guidewire. The anatomical shape of the calcaneus creates a situation in which guidewire placement can be skewed on imaging based on the angle of either internal or external rotation. As a result, the aims of our study were to (1) determine the optimal angle(s) of rotation required to accurately depict guidewire placement on imaging and (2) evaluate and describe the effects angle of rotation has on physician assessment of guidewire placement. Using a C-arm x-ray, images of cadavers with both correctly and incorrectly placed guidewires were taken at 5° increments of internal and external rotation of the cadaveric lower extremity and assessed for accuracy of guidewire depiction. The images revealed that the correctly placed guidewire appeared displaced medially at angles of 35° and 40° of external rotation. Conversely, the incorrectly placed guidewire appeared to be correctly placed at between 10° and 40° of external rotation. These images were then disseminated to various physicians including orthopedic surgeons and podiatrists to determine the ability of physicians to correctly appreciate guidewire placement. Using the responses from 35 physicians, it was found that certain angles of internal and external rotation preclude physicians from correctly determining guidewire placement. We found, based on chi-square analysis, that we were able to reject our null hypothesis with a p value of <.001 leading to the conclusion that indeed angle of rotation and guidewire placement can lead to false depictions of guidewire placement. In conclusion, our study gave objective measurements to guide foot placement during tibiotalocalcaneal fusion to decrease the risk incorrectly depicted medial guidewire placement and subsequent incorrect intramedullary nail placement.

Bone marrow-derived stem/stromal cells (BMSC) 3D microtissues cultured in BMP-2 supplemented osteogenic induction medium are prone to adipogenesis.

Bone marrow-derived mesenchymal stem/stromal cells (BMSC) may facilitate bone repair through secretion of factors that stimulate endogenous repair processes or through direct contribution to new bone through differentiation into osteoblast-like cells. BMSC microtissue culture and differentiation has been widely explored recently, with high-throughput platforms making large-scale manufacture of microtissues increasingly feasible. Bone-like BMSC microtissues could offer an elegant method to enhance bone repair, especially in small-volume non-union defects, where small diameter microtissues could be delivered orthoscopically. Using a high-throughput microwell platform, our data demonstrate that (1) BMSC in 3D microtissue culture result in tissue compaction, rather than growth, (2) not all mineralised bone-like matrix is incorporated in the bulk microtissue mass and (3) a significant amount of lipid vacuole formation is observed in BMSC microtissues exposed to BMP-2. These factors should be considered when optimising BMSC osteogenesis in microtissues or developing BMSC microtissue-based therapeutic delivery processes.

Genotoxic risk of ethyl-paraben could be related to telomere shortening.

The ability of parabens to promote the appearance of multiple cancer hallmarks in breast epithelium cells provides grounds for regulatory review of the implication of the presence of parabens in human breast tissue. It is well documented that telomere dysfunction plays a significant role in the initiation of genomic instability during carcinogenesis in human breast cancer. In the present study, we evaluated the genotoxic effect of ethyl 4-hydroxybenzoate (ethyl-paraben), with and without metabolic activation (S9), in studies following OECD guidelines. We observed a significant increase in genotoxic damage using the Mouse Lymphoma Assay and in vitro micronucleus (MN) tests in the L5178Y cell line in the presence of S9 only after a short exposure. A high frequency of MN was observed in the TK6 cells after a short exposure (3 h) in the presence of S9 and a long exposure (26 h) without S9. We found significant increases in the MN frequency and induced chromosomal aberrations in the lymphocytes of only one donor after ethyl-paraben exposure in the presence of S9 after a short exposure. Cytogenetic characterization of the paraben-treated cells demonstrated telomere shortening associated with telomere loss and telomere deletions in L5178Y and TK6 cells and lymphocytes of the paraben sensitive-donor. In a control cohort of 68 human lymphocytes, telomere length and telomere aberrations were age-dependent and showed high inter-individual variation. This study is the first to link telomere shortening and the genotoxic effect of ethyl paraben in the presence of S9 and raises the possibility that telomere shortening may be a proxy for underlying inter-individual sensitivity to ethyl-paraben. Copyright © 2016 John Wiley & Sons, Ltd.

Extreme ocean acidification reduces the susceptibility of eastern oyster shells to a polydorid parasite.

Ocean acidification poses a threat to marine organisms. While the physiological and behavioural effects of ocean acidification have received much attention, the effects of acidification on the susceptibility of farmed shellfish to parasitic infections are poorly understood. Here we describe the effects of moderate (pH 7.5) and extreme (pH 7.0) ocean acidification on the susceptibility of Crassostrea virginica shells to infection by a parasitic polydorid, Polydora websteri. Under laboratory conditions, shells were exposed to three pH treatments (7.0, 7.5 and 8.0) for 3- and 5-week periods. Treated shells were subsequently transferred to an oyster aquaculture site (which had recently reported an outbreak of P. websteri) for 50 days to test for effects of pH and exposure time on P. websteri recruitment to oyster shells. Results indicated that pH and exposure time did not affect the length, width or weight of the shells. Interestingly, P. websteri counts were significantly lower under extreme (pH 7.0; ~50% reduction), but not moderate (pH 7.5; ~20% reduction) acidification levels; exposure time had no effect. This study suggests that extreme levels - but not current and projected near-future levels - of acidification (∆pH ~1 unit) can reduce the susceptibility of eastern oyster shells to P. websteri infections.

Murine, but not human, ephrin-B2 can be efficiently cleaved by the serine protease kallikrein-4: implications for xenograft models of human prostate cancer.

BACKGROUND: Ephrin-B2 is the sole physiologically-relevant ligand of the receptor tyrosine kinase EphB4, which is over-expressed in many epithelial cancers, including 66% of prostate cancers, and contributes to cancer cell survival, invasion and migration. Crucially, however, the cancer-promoting EphB4 signalling pathways are independent of interaction with its ligand ephrin-B2, as activation of ligand-dependent signalling causes tumour suppression. Ephrin-B2, however, is often found on the surface of endothelial cells of the tumour vasculature, where it can regulate angiogenesis to support tumour growth. Proteolytic cleavage of endothelial cell ephrin-B2 has previously been suggested as one mechanism whereby the interaction between tumour cell-expressed EphB4 and endothelial cell ephrin-B2 is regulated to support both cancer promotion and angiogenesis. METHODS: An in silico approach was used to search accessible surfaces of 3D protein models for cleavage sites for the key prostate cancer serine protease, KLK4, and this identified murine ephrin-B2 as a potential KLK4 substrate. Mouse ephrin-B2 was then confirmed as a KLK4 substrate by in vitro incubation of recombinant mouse ephrin-B2 with active recombinant human KLK4. Cleavage products were visualised by SDS-PAGE, silver staining and Western blot and confirmed by N-terminal sequencing. RESULTS: At low molar ratios, KLK4 cleaved murine ephrin-B2 but other prostate-specific KLK family members (KLK2 and KLK3/PSA) were less efficient, suggesting cleavage was KLK4-selective. The primary KLK4 cleavage site in murine ephrin-B2 was verified and shown to correspond to one of the in silico predicted sites between extracellular domain residues arginine 178 and asparagine 179. Surprisingly, the highly homologous human ephrin-B2 was poorly cleaved by KLK4 at these low molar ratios, likely due to the 3 amino acid differences at this primary cleavage site. CONCLUSION: These data suggest that in in vivo mouse xenograft models, endogenous mouse ephrin-B2, but not human tumour ephrin-B2, may be a downstream target of cancer cell secreted human KLK4. This is a critical consideration when interpreting data from murine explants of human EphB4+/KLK4+ cancer cells, such as prostate cancer cells, where differential effects may be seen in mouse models as opposed to human clinical situations.

Evaluating Blood Loss and the Effect of Antiplatelet Treatment in Foot and Ankle Amputations.

The interrelationship between diabetes mellitus and cardiovascular disease is well-documented, and, secondary to the latter, is the use of antiplatelet therapy. Although diabetes and the associated vascular manifestations are driving forces behind lower extremity amputations, few data are available on the risks of perioperative antiplatelet therapy with foot and ankle amputations. The goal of the present study was to address the surgical effect of continuing or discontinuing antiplatelet therapy before foot and/or ankle amputation. The following data were retrospectively collected: blood loss, pre- and postoperative hematocrit and hemoglobin, operative time, amputation type, age, diabetic status, antiplatelet treatment, and number of transfusions during the perioperative period. Perioperative antiplatelet therapy was defined as exposure to aspirin or clopidogrel within 3 days before surgery. To compare the outcomes between groups, the following factors were analyzed using bivariate analyses and then multivariate regression models: (1) the need for transfusions, (2) high blood loss (>20 mL), (3) volume of blood loss, and (4) operative time. The noninferiority of continued antiplatelet use was assessed in terms of operative time and blood loss, using a noninferiority margin of 10 minutes or 10 mL, respectively. Antiplatelet therapy was not a statistically significant risk factor for any of the studied outcomes on multivariate analysis. Equivalence testing revealed that continuing antiplatelet therapy is not inferior to discontinuing perioperative therapy in terms of blood loss and operative time. Multivariate analysis of the data suggested that antiplatelet therapy has no statistically significant impact on blood loss, transfusion rate, or operative time.

Is Subtalar Joint Cartilage Resection Necessary for Tibiotalocalcaneal Arthrodesis via Intramedullary Nail? A Multicenter Evaluation.

Tibiotalocalcaneal arthrodesis with intramedullary nailing is traditionally performed with formal preparation of both the subtalar and ankle joints. However, we believe that subtalar joint preparation is not necessary to achieve satisfactory outcomes in patients undergoing tibiotalocalcaneal arthrodesis with a retrograde intramedullary nail. The primary aim of the present retrospective study was to evaluate the outcomes of patients who had undergone tibiotalocalcaneal arthrodesis with an intramedullary nail without formal subtalar joint cartilage resection. A multicenter medical record review was performed to identify consecutive patients. Pain was assessed using a visual analog scale, and osseous union at the tibiotalar joint was defined as bony trabeculation across the arthrodesis site on all 3 radiographic views. Progression of joint deterioration was evaluated across time at the subtalar joint, using a modified grading system developed by Takakura et al. Forty consecutive patients (aged 61.9 ± 12.9 years; 17 men) met the inclusion and exclusion criteria. Compared with the pain reported preoperatively (6.4 ± 2.7), a statistically significant decline was seen in the pain experienced after surgery (1.2 ± 1.8; p < .001). The mean time to consolidated arthrodesis at the ankle joint was 3.8 ± 1.5 months. A statistically significant increase in deterioration at the subtalar joint was observed across time [t(36) = -6.200, p < .001]. Compared with previously published data of subtalar joint cartilage resection, the present study has demonstrated a similar decline in pain, with a high rate of union, and also a decrease in operative time when preparation of the subtalar joint was not performed.

The Association of Surgeons in Training (ASiT) Consensus Statement on Major Trauma Training in the UK.

INTRODUCTION: Since the establishment of the Major Trauma Networks in 2012, it is estimated that an extra 1,600 lives have been saved across England. Although the delivery of trauma care has improved significantly, the provision of trauma training has not and remains fragmented. The Association of Surgeons in Training (ASiT), an independent organisation run by trainees, is dedicated to excellence in surgical training within the United Kingdom (UK) and Republic of Ireland (ROI). The aim of this study was to develop a consensus statement representing the views of the ASiT on the future of trauma surgery training. METHODS: A modified nominal group technique was used in five stages: 1, scoping exercise; 2, virtual consultation; 3, nominal group consensus meeting; 4, virtual feedback from stakeholders; and 5, virtual confirmation by the ASiT Council. The design and reporting of the consensus followed best practice methodology for consensus research. RESULTS: Overall, 62 participants gave 90 statements across stages 1-3. Eleven key themes were identified, all of which met the consensus of the ASiT Council. The key findings were widespread support for increased exposure to trauma for medical students and early surgical trainees as well as an increased use of simulation methods and improved focus on non-technical skills within trauma surgery. CONCLUSIONS: This study sets out the position of the ASiT on the future of trauma surgery training and how training in major trauma surgery in the UK and ROI could be improved.

Mucosal immune responses induced by transcutaneous vaccines.

The skin has been investigated as a site for vaccine delivery only since the late 1990s. However, much has been discovered about the cell populations that reside in the skin, their active role in immune responses, and the fate of trans- cutaneously applied antigens. Transcutaneous immunization (TCI) is a safe, effective means of inducing immune responses against a number of pathogens. One of the most notable benefits of TCI is the induction of immune responses in both systemic and mucosal compartments. This chapter focuses on the transport of antigen into and beyond intact skin, the cutaneous sentinel cell populations that play a role in TCI, and the types of mucosal immune responses that have been generated. A number of in vivo studies in murine models have provided information about the broad responses induced by TCI. Cellular and humoral responses and protection against challenge have been noted in the gastrointestinal, reproductive, and respiratory tracts. Clinical trials have demonstrated the benefits of this vaccine delivery route in humans. As with other routes of immunization, the type of vaccine formulation and choice of adjuvant may be critical for achieving appropriate responses and can be tailored to activate specific immune-responsive cells in the skin to increase the efficacy of TCI against mucosal pathogens.

'Factors influencing future career choices of Queen's University Belfast Medical students.'

INTRODUCTION: Decisions made by medical students on future career choice have demonstrated concordance with subsequent postgraduate career path. This study aimed to understand the factors that impact undergraduate career decision making. METHODS: An anonymous voluntary survey consisting of binominal, Likert and free text responses was distributed to all medical students registered at Queen's University Belfast (QUB). Data was collected over 6 weeks in April-May 2021. The primary outcome was future career aspirations. The secondary outcomes were the impact of mentorship on career choice, the likelihood of students completing their medical degree and practicing medicine upon graduation. Local ethical approval was obtained. RESULTS: 202 responses were received (response rate 15%). 67% (n = 135) were female. One third of respondents remained undecided about their future career choice. Surgery was both the most popular definite career choice (16.3%) of respondents, butalsothespecialtymarkedmostoftenas'Least preferred Specialty' (33%). Factors positively influencing career choice were academic interest and flexibility in working hours. Negative predictors of career choice were lack of interest in the area, perceived workload, and duration of training schemes. 71% (n=144) of respondents reported that a subspecialty mentor would positively influence their career choice and two-thirds of respondents reported that financial factors would influence their career decision. 11% (n= 22) of respondents were unsure or undecided if they would continue medicine as a career upon graduation. CONCLUSION: Uncertainty over future career intention remains common with surgery the least popular speciality. Mentorship, integrating flexibility in training and enhancing academic interest should be considered by educational stakeholders as mechanisms to generating undergraduate interest in a subspecialty. Furthermore, the reported rate of students intention to leave their medical degree prior to graduation by this cohort is concerning, warranting further investigation.

Use of allograft cellular bone matrix in multistage talectomy with tibiocalcaneal arthrodesis: a case report.

Surgical treatment for traumatic dislocation of the talus is a challenging procedure that is often associated with complications. Application of allograft cellular bone matrix with viable mesenchymal stem and osteoprogenitor cells can eliminate the need for autograft and may increase fusion rates in procedures such as tibiocalcaneal arthrodesis. This report describes the treatment of an adult man who presented with a right ankle fracture and subtalar joint dislocation after a motor vehicle accident. After initial treatment with open reduction and internal fixation, the patient developed avascular necrosis of the talus and septic arthritis of the tibiotalar and subtalar joints. After treatment of the infection, the patient was ultimately treated with multistage talectomy and tibiocalcaneal arthrodesis augmented with a cellular bone allograft. Approximately 3 months after the final operation, plain radiographs and computed tomography confirmed solid fusion at the arthrodesis interface. The patient's recovery was uneventful thereafter, and amputation was avoided. This case, which presented additional challenges because of the large defect created by the infection, suggests that use of an allograft cellular bone matrix has the potential to replicate the bone-healing properties of autograft without the constraints and morbidity associated with autograft harvesting.

Management of combined soft tissue and osseous defect of the midfoot with a free osteocutaneous radial forearm flap: a case report.

Extensive soft tissue and osseous defects of the foot are difficult to manage and often result in amputation. Most of these wounds are created by trauma, but other causes, such as infection and malignancy, can create similar defects. A variety of wound management options exist for the treatment of these challenging wounds, including negative pressure wound therapy, autogenous skin grafting, and the use of skin substitutes, as well as internal and external fixation methods. In the present report, we describe the use of a free osteocutaneous radial forearm flap to manage a 10-cm × 5-cm dorsal soft tissue defect and a 2.5-cm second metatarsal diaphyseal defect in an adult male.

Recent advancements and application of in vitro models for predicting inhalation toxicity in humans.

Animals have been indispensable in testing chemicals that can pose a risk to human health, including those delivered by inhalation. In recent years, the combination of societal debate on the use of animals in research and testing, the drive to continually enhance testing methodologies, and technology advancements have prompted a range of initiatives to develop non-animal alternative approaches for toxicity testing. In this review, we discuss emerging in vitro techniques being developed for the testing of inhaled compounds. Advanced tissue models that are able to recreate the human response to toxic exposures alongside examples of their ability to complement in vivo techniques are described. Furthermore, technology being developed that can provide multi-organ toxicity assessments are discussed.

Quantitative Viral Outgrowth Assay to Measure the Functional SIV Reservoir in Myeloid Cells.

The role of CD4+ T cells in HIV infection and the latent reservoir, that is, latently infected cells that harbor replication competent virus, has been rigorously assessed. We have previously reported a quantitative viral outgrowth assay (QVOA) for SIV that demonstrated the frequency of latently infected CD4+ T cells is approximately 1 in a million cells, similar to that of HIV infected individuals on ART. However, the frequency of productively infected monocytes in blood and macrophages in tissues has not been similarly studied. Myeloid cells are infected during acute HIV and SIV infection; however, unlike lymphocytes, they are resistant to the cytopathic effects of the virus. Moreover, tissue-resident macrophages have the ability to self-renew and persist in the body for months to years. Thus, tissue macrophages, once infected, have the characteristics of a stable viral reservoir. A better understanding of the number of productively infected macrophages is critical to understanding the role of infected myeloid cells as a viral reservoir. In order to assess the functional latent reservoir. we have developed specific QVOAs for monocytes in blood, and macrophages in spleen, BAL and brain, which are described in detail in this chapter.

Identification of a novel prostate cancer susceptibility variant in the KLK3 gene transcript.

Genome-wide association studies (GWAS) have identified more than 30 prostate cancer (PrCa) susceptibility loci. One of these (rs2735839) is located close to a plausible candidate susceptibility gene, KLK3, which encodes prostate-specific antigen (PSA). PSA is widely used as a biomarker for PrCa detection and disease monitoring. To refine the association between PrCa and variants in this region, we used genotyping data from a two-stage GWAS using samples from the UK and Australia, and the Cancer Genetic Markers of Susceptibility (CGEMS) study. Genotypes were imputed for 197 and 312 single nucleotide polymorphisms (SNPs) from HapMap2 and the 1000 Genome Project, respectively. The most significant association with PrCa was with a previously unidentified SNP, rs17632542 (combined P = 3.9 × 10(-22)). This association was confirmed by direct genotyping in three stages of the UK/Australian GWAS, involving 10,405 cases and 10,681 controls (combined P = 1.9 × 10(-34)). rs17632542 is also shown to be associated with PSA levels and it is a non-synonymous coding SNP (Ile179Thr) in KLK3. Using molecular dynamic simulation, we showed evidence that this variant has the potential to introduce alterations in the protein or affect RNA splicing. We propose that rs17632542 may directly influence PrCa risk.