Tissue Qualities Research Articles

Reduced Cell Migration in Human Chondrocyte Sheets Increases Tissue Stiffness and Cartilage Protein Production.

Chondrogenic differentiation medium (CDM) is usually used to maintain chondrogenic activity during chondrocyte sheet production. However, tissue qualities remain to be determined as to what factors improve cell functions. Moreover, the relationship between CDM and cell migration proteins has not been reported. In this study, the effect of CDM on the behavior of chondrocyte sheets was investigated. Structural analysis, mechanical testing and proteomics were performed to observe tissue qualities. The relationship between CDM and cell migration proteins were investigated using time-lapse observations and bioinformatic analysis. During 48h, CDM affected the chondrocyte behaviors by reducing cell migration. Compared to the basal medium, CDM impacted the contraction of monolayered chondrocyte sheets. At day 7, the contracted sheets increased tissue thickness and improved tissue stiffness. Cartilage specific proteins were also upregulated. Remarkedly, the chondrocyte sheets in CDM displayed downregulated proteins related to cell migration. Bioinformatic analysis revealed that TGFβ1 was shown to be associated with cartilage functions and cell migration. Pathway analysis of chondrocyte sheets in CDM also revealed the presence of a TGFβ pathway without activating actin production, which might be involved in synthesizing cartilage-specific proteins. Cell migration pathway showed MAPK signaling in both cultures of the chondrocyte sheets. Reduced cell migration in the chondrocyte sheet affected the tissue quality. Using CDM, TGFβ1 might trigger cartilage protein production through the TGFβ pathway and be involved in cell migration via the MAPK signaling pathway. Understanding cell behaviors and their protein expression would be beneficial for developing high-quality tissue-engineered cartilage.

Comparison of hypospadias phenotype pixel segmentation to GMS score

Hypospadias phenotype assessment determines if the anatomy is favorable for reconstruction. Glans-Urethral Meatus-Shaft (GMS) has been adopted in an effort to standardize hypospadias classification. While extremely subjective, GMS has been widely used to classify the severity of the phenotype to predict surgical outcomes. The use of digital image analysis has proven to be feasible and prior efforts by our team have demonstrated that machine learning algorithms can emulate an expert's assessment of the phenotype. Nonetheless, the creation of these image recognition algorithms is highly subjective. In order to reduce a subjective input in the evaluation of the phenotype, we propose a novel approach to analyze the anatomy using digital image pixel analysis and to compare the results using the GMS score. Our hypothesis is that pixel cluster segmentation can discriminate between favorable and unfavorable anatomy. To evaluate whether image segmentation and digital pixel analysis are able to analyze favorable vs unfavorable hypospadias anatomy in a less subjective manner than GMS score. A total of 148 patients with different types of hypospadias were classified by 1 of 5 independent experts following the GMS score into "favorable" (GG), "moderately favorable" (GM) and "unfavorable" (GP) glans. From there, 592 images were generated using digital image segmentation. 584 were included for final analysis due to certain images being excluded for poor image quality or inadequate capture of target anatomy. For each image, the region of interest was segmented separately by two evaluators into "glans," "urethral plate," "foreskin" and "periurethral plate". The values obtained for each segmented region using machine-learning statistical pixel k-means cluster analysis were analyzed and compared to the GMS score given to that image using an ANOVA analysis. Analysis of image segmentation demonstrated that k-means pixel cluster analysis discriminated "favorable" vs "unfavorable" urethral plates. There was a significant difference between scores when comparing the GG and GM groups (p=0.03) and GG and GP groups (p=0.05). Pixel cluster analysis could not discriminate between "moderately favorable" and "unfavorable" urethral plates. Through our analysis, we found significant pairwise difference for different tissue qualities. Digital image segmentation and statistical k-means cluster analysis can discriminate anatomical features in a similar way to the GMS score. Future research can target discerning between different tissue qualities in an effort to predict surgical outcomes for hypospadias repair.

Development of the McMaster Embalming Scale (MES) to assess embalming solutions for surgical skills training.

Human cadavers used for surgical training are embalmed using various methods to facilitate tissue storage and longevity while preserving the natural characteristics required to achieve high fidelity functional task alignment. However, there are no standardized means to evaluate the suitability of embalming solutions for this purpose. The McMaster Embalming Scale (MES) was developed to assess the extent to which embalming solutions allow tissues to achieve physical and functional correspondence to clinical contexts. The MES follows a five-point Likert scale format and evaluates the effect of embalming solutions on tissue utility in seven domains. This study aims to determine the reliability and validity of the MES by presenting it to users after performing surgical skills on tissues embalmed using various solutions. A pilot study of the MES was conducted using porcine material. Surgical residents of all levels and faculty were recruited via the Surgical Foundations program at McMaster University. Porcine tissue was unembalmed (fresh- frozen) or embalmed using one of seven solutions identified in the literature. Participants were blinded to the embalming method as they completed four surgical skills on the tissue. After each performance, participants evaluated their experience using the MES. Internal consistency was evaluated using Cronbach's alpha. Domain to total correlations and a g-study were also conducted. Formalin-fixed tissue achieved the lowest average scores, while fresh frozen tissue achieved the highest. Tissues preserved using Surgical Reality Fluid (Trinity Fluids, LLC, Harsens Island, MI) achieved the highest scores among embalmed tissues. The Cronbach's alpha scores varied between 0.85-0.92, indicating a random sample of new raters would offer similar ratings using the MES. All domains except odor were positively correlated. The g-study indicated that the MES is able to differentiate between embalming solutions, but an individual rater's preference for certain tissue qualities also contributes to the variance in scores captured. This study evaluated the psychometric characteristics of the MES. Future steps to this investigation include validating the MES on human cadavers. This article is protected by copyright. All rights reserved.

Kidney xenotransplantation in a brain-dead donor: Glass half-full or half-empty?

Kidney xenotransplantation in a brain-dead donor: Glass half-full or half-empty?

A Pilot Comparative Study of Submerge vs. Non- Submerg Saturated Salt Solution Human Cadavers Embalming Method by Gross, Histological, and Microbiological Evaluation

Objective: To investigate and develop the saturated salt embalming method and evaluate the cadavers.Materials and Methods: Eight cadavers were embalmed with a saturated salt solution (SSS) by submerged (SG, N=2) and non-submerged (NSG, N=6), then evaluated by gross dissection, which compared to living humans, fresh and Thiel’s cadavers. The histological evaluation was compared to textbook pictures. The assessments were recorded on a Likert scale from 0 (no resemblance) to 5 (most resemblance). Pre-and post-embalming swabs were collected for bacterial and fungal cultures and lung tissues for acid-fast staining and mycobacterial cultures. Comparisons between the evaluated items were performed using the Kruskal–Wallis test. The Likert scale results were reported by percentage.Results: The submerge method (N=2) was terminated after three months of embalming because it showed insufficient quality for dissection. Six cadavers in NSG had gross tissue qualities that resembled living humans or fresh cadavers on a scale of 3 or 4. NSG had excellent joint flexibility. The histological tissues showed similarity to textbook pictures, with a scale of 4 or 5. There were bacterial and fungal cultures at the end of embalming. The pathogenic bacteria were Clostridium perfringens and Pseudomonas aeruginosa. Mycobacterium cultures were negative.Conclusion: Injected SSS, 80% total body water volume, is a promising embalming method that yields cadavers with high tissue quality, flexible joints, and good histological structures. However, this technique cannot eliminate bacteria and normal flora. It may result from the tropical climate setting.

Inorganic Nanoparticles in Bone Healing Applications.

Modern biomedicine aims to develop integrated solutions that use medical, biotechnological, materials science, and engineering concepts to create functional alternatives for the specific, selective, and accurate management of medical conditions. In the particular case of tissue engineering, designing a model that simulates all tissue qualities and fulfills all tissue requirements is a continuous challenge in the field of bone regeneration. The therapeutic protocols used for bone healing applications are limited by the hierarchical nature and extensive vascularization of osseous tissue, especially in large bone lesions. In this regard, nanotechnology paves the way for a new era in bone treatment, repair and regeneration, by enabling the fabrication of complex nanostructures that are similar to those found in the natural bone and which exhibit multifunctional bioactivity. This review aims to lay out the tremendous outcomes of using inorganic nanoparticles in bone healing applications, including bone repair and regeneration, and modern therapeutic strategies for bone-related pathologies.

Comparison of Bioelectrical Impedance Parameters and Body Composition Among Street Workout Athletes According to Training Experience

Bioelectrical impedance analysis (BIA) is useful for determining bioelectrical parameters and body composition. In turn, differences have been reported when comparing these variables in athletes by training status. Nevertheless, there is no evidence of bioelectrical impedance parameters in Street Workout (SW) athletes. Thus, this study aimed to compare bioelectrical parameters and body composition through BIA between trained and untrained SW athletes. Twenty-two male SW athletes were classified as trained (n=6; 26.3 y [21.0-28.9]) and untrained (n=16; 21.8 y [20.5-24.7]) based on their SW experience. A bioelectrical impedanciometer was used to estimate bioelectrical parameters and body composition. There was no difference in body composition between trained and untrained SW athletes. Regarding impedance, trained athletes had lower values in the upper limbs (right arm: p=0.049; left arm: p=0.027) and trunk (p=0.004), while phase angle values were higher in the upper limbs (right arm: p=0.004; left arm: p=0.001), and trunk (p=0.006), as well as the mean phase angle (p=0.007), than untrained athletes. Bioelectrical impedance parameter differences found between SW training level groups suggest an improvement of tissue qualities, such as muscle, with SW practice. Future longitudinal studies should corroborate if SW training modifies these parameters.

Ex vivo biaxial load testing analysis of aortic biomechanics demonstrates variation in elastic energy distribution across the aortic zone zero

ObjectivesWe hypothesized that tissue characteristics vary significantly along zone zero, which may be reflected by regional differences in stored elastic energy. Our objectives were to (1) characterize the regional variation in stored elastic energy within tissues of the aortic zone zero and (2) identify the association between this variation and patient characteristics. MethodsFrom February 2018 to January 2021, 123 aortic tissue samples were obtained from the aortic root and proximal and distal ascending aortas of 65 adults undergoing elective ascending aorta replacement. Biaxial biomechanics testing was performed to obtain tissue elastic energy at the inflection point and compared with patient demographics and preoperative computed tomography imaging. Coefficient models were fit using B-spline to interrogate the relationship among elastic energy, region, and patient characteristics. ResultsMean elastic energy at inflection point was 24.3 ± 15.6 kJ/m3. Elastic energy increased significantly between the root and proximal, and root and distal ascending aorta and decreased with increasing age. Differences due to history of connective tissue disorder and bicuspid aortic valve were significant but diminished when controlled for other patient characteristics. Among covariates, age and region were found to be the most important predictors for elastic energy. ConclusionsAortic tissue biomechanical metrics varied across regions and with patient characteristics within the aortic zone zero. Assessment of endovascular outcomes in the ascending aorta must closely consider the region of deployment and variable tissue qualities along the length of the landing zone. Regional variation in tissue characteristics should be incorporated into existing patient-specific models of aortic mechanics.

Immediate effect of a spinal mobilisation intervention on muscle stiffness, tone and elasticity in subjects with lower back pain – A randomized cross-over trial

BackgroundDespite the lack of objective evidence, spinal manual therapies have been common practice for many years, particularly for treatment of lower back pain (LBP). This exploratory study measured and analysed the effect of a spinal mobilisation intervention on muscle tissue quality in LBP sufferers. Methods40 people with LBP participated in a within-subject repeated measures cross-over study with intervention and control conditions. A myometer was used to assess the change in para-spinal muscle tissue quality before and after the intervention. Analysis considered the magnitude of muscle response together with individual covariates as potential contributors. ResultsA significant post-intervention reduction was observed in muscle stiffness (p = 0.012, η 2 partial = 0.15), tone (p = 0.001, η 2 partial = 0.25) and elasticity (p = 0.001, η 2 partial = 0.24). Significant increases were seen in 2 variables post-control: stiffness (p = 0.004, η 2 partial = 0.19), tone (p = 0.006, η 2 partial = 0.18) and a significant decrease in elasticity (p ˂ 0.000, η 2 partial = 0.3). Significant contributing covariates include baseline stiffness, BMI, waist circumference and sex. Baseline stiffness and tone were significantly correlated to their response levels. ConclusionsThe significant reduction in all muscle tissue qualities following the intervention provide preliminary data for an evidence-based LBP therapeutic. Baseline stiffness, BMI, waist circumference and sex could act as significant contributors to magnitude of response. The results warrant further investigation into spinal mobilisation therapies to further build the objective evidence base.

Design and Fabrication of a Customized Partial Hip Prosthesis Employing CT-Scan Data and Lattice Porous Structures.

As a larger elderly human population is expected worldwide in the next 30 years, the occurrence of aging-associated illnesses will also be increased. The use of prosthetic devices by this population is currently important and will be even more dramatic in the near future. Hence, the design of prosthetic devices able to reduce some of the problems associated with the use of current components, such as stress shielding, reduced mobility, infection, discomfort, etc., becomes relevant. The use of additive manufacturing (AM) and the design fabrication of self-supported cellular structures in the biomedical area have opened up important opportunities for controlling the physical and mechanical properties of hip implants, resulting in specific benefits for the patients. Different studies have reported the development of hip prosthetic designs employing AM, although there are still opportunities for improvement when it comes to customized design and tuning of the physical and mechanical properties of such implants. This work shows the design and manufacture by AM of a personalized stainless-steel partial hip implant using tomography data and self-supported triply periodic minimal surface (TPMS) cell structures; the design considers dimensional criteria established by international standards. By employing tomography data, the external dimensions of the implant were established and the bone density of a specific patient was calculated; the density and mechanical properties in compression of the implant were modulated by employing an internal gyroid-type cell structure. Using such a cell structure, the patient’s bone density was emulated; also, the mechanical properties of the implant were fine-tuned in order to make them comparable to those reported for the bone tissue replaced by the prosthesis. The implant design and manufacturing methodology developed in this work considered the clinical condition of a specific patient and can be reproduced and adjusted for different types of bone tissue qualities for specific clinical requirements.

The influence of “Biostrong 510” additive on the meat productivity of broiler chickens

Vegetable feed additive “Biostrong 510” based on essential oils and plant substances contains active substances exclusively of vegetable origin, which have a more intense eff ect on the animal’s body. The mechanism of action is based on the synergism of several plant substances containing active substances that, when combined, aff ect a certain category of animals. The additive contains essential oils, herbal plants, and seasonings such as anise oil, thyme oil, gentian powder, chili paprika powder, and quillaya extract. The purpose of the research was to determine the feasibility and eff ectiveness of fortifi cation of compound feed with the vegetable feed additive based on essential oils and vegetable substances to increase meat productivity and meat quality. In order to study the eff ectiveness of feeding vegetable feed additive in compound feed for broiler chickens under the conditions of LLC “Akashevskaya poultry Farm” in the Republic of Mari El, a scientifi c and economic experiment has been carried out. Experiments have been performed on broiler chickens of the cross Cobb-500 from the daily to 40-day age of the birds. The eff ect of the vegetable feed additive “Biostrong 510” based on essential oils and vegetable substances on meat productivity and nutritional value of broiler chicken meat has been studied in the paper. The level of feeding and the quality of the feed consumed by poultry has a big infl uence on meat productivity. The use of our selected vegetable feed additive based on essential oils and vegetable substances increase the slaughter weight by 9,0–13,7 %, the slaughter yield by 2–5 %, the amount of muscle tissue and meat qualities of carcasses. The best results have been obtained by including the vegetable feed additive based on essential oils and plant substances in the amount of 0,015 % of the dry substance of the feed.

Three-dimensional modeling of human neurodegeneration: brain organoids coming of age.

The prevalence of dementia and other neurodegenerative diseases is rapidly increasing in aging nations. These relentless and progressive diseases remain largely without disease-modifying treatments despite decades of research and investments. It is becoming clear that traditional two-dimensional culture and animal model systems, while providing valuable insights on the major pathophysiological pathways associated with these diseases, have not translated well to patients' bedside. Fortunately, the advent of induced-pluripotent stem cells and three-dimensional cell culture now provide toolsthat are revolutionizing the study of human diseases by permitting analysis of patient-derived human tissue with non-invasive procedures. Specifically, brain organoids, self-organizing neural structures that can mimic human fetal brain development, have now been harnessed to develop alternative models of Alzheimer's disease, Parkinson's disease, motor neuron disease, and Frontotemporal dementia by recapitulating important neuropathological hallmarks found in these disorders. Despite these early breakthroughs, several limitations need to be vetted in brain organoid models in order to more faithfully match human tissue qualities, including relative tissue immaturity, lack of vascularization and incomplete cellular diversity found in this culture system. Here, we review current brain organoid protocols, the pathophysiology of neurodegenerative disorders, and early studies with brain organoid neurodegeneration models. We then discuss the multiple engineering and conceptual challenges surrounding their use and provide possible solutions and exciting avenues to be pursued. Altogether, we believe that brain organoids models, improved with classical and emerging molecular and analytic tools, have the potential to unravel the opaque pathophysiological mechanisms of neurodegeneration and devise novel treatments for an array of neurodegenerative disorders.

Modern Primary Breast Augmentation: Best Recommendations for Best Results.

After reading this article, the participant should be able to: 1. Develop a practical method for preoperative implant size selection. 2. List characteristics and examples of fourth- and fifth-generation silicone implants. 3. Recognize the differences in "profile" designations across implant manufacturers. 4. Recall updated statistics on breast implant-associated anaplastic large cell lymphoma and describe current guidelines on disease diagnosis and treatment. 5. Apply atraumatic and aseptic surgical techniques in primary breast augmentation. Modern primary breast augmentation requires an intimate knowledge of the expanding breast implant market, including characteristics of current generation silicone implants and "profile" types. Optimal implant size selection requires balancing patient desires with tissue qualities. Evidence and awareness of breast implant-associated anaplastic large cell lymphoma continue to grow, and patients and surgeons alike should be informed on the most updated facts of the disease entity. Atraumatic surgical technique and aseptic adjuncts are critical in reducing periprosthetic inflammation and contamination, both of which are known instigators of capsular contracture and potentially breast implant-associated anaplastic large cell lymphoma.

A method that accounts for differential detectability in mixed samples of long‐term infections with applications to the case of chronic wasting disease in cervids

Abstract Surveillance of wildlife diseases is logistically difficult, and imperfect detection is a recurrent challenge for disease estimation. Using citizen science can increase sample sizes, but it is associated with a cost in terms of the anatomical type and quality of the sample. Additionally, biological tissue samples from remote areas lose quality due to autolysis. These challenges are faced in the case of emerging chronic wasting disease (CWD) in cervids. Here, we develop a stochastic scenario tree model of diagnostic sensitivity, allowing for a mixture of tissue sample types (lymph nodes and brain) and qualities while accounting for different detection probabilities during the CWD infection, lasting 2–3 years. We apply the diagnostic sensitivity in a Bayesian framework, enabling estimation of age‐class‐specific true prevalence, including the prevalence in latent, recently infected stages. We provide a simulation framework to estimate the sensitivity of the surveillance system (i.e., the probability of detecting the infection in a given population), when detectability varies among individuals due to different disease progression. We demonstrate the utility of our framework by applying it to the recent emergence of CWD in a European population of reindeer. We estimated apparent CWD prevalence at 1.2% of adults in the infected population of wild reindeer, while the true prevalence was 1.6%. The sensitivity estimation of the CWD surveillance was performed in an adjacent small (c. 500) and a large (c. 10,000) reindeer population, demonstrating low certainty of CWD absence. Our method has immediate application to the mandatory testing for CWD in EU countries commencing in 2018. Similar approaches that account for latent stages and a serial disease progression in various tissues with a temporal pattern of diagnostic sensitivity may enhance the estimation of the prevalence of wildlife diseases more generally.

Do cell based tissue engineering products for meniscus regeneration influence vascularization?

Meniscus regeneration is observed within the peripheral, vascularized zone but decreases in the inner two thirds alongside the vascularization. Within this avascular area, cell-based tissue-engineering-approaches appear to be a promising strategy for the treatment of meniscal defects. Evaluation of the angiogenic potential of cell-based tissue-engineering-products for meniscus healing. Evaluation of angiogenesis induced by rabbit meniscus-pellets, meniscus-cells (MC) or mesenchymal stem-cells (MSC) in cell-based tissue-engineering-products within a rabbit meniscus-ring was performed using a transparent dorsal skin fold chamber in nude mice. Observations were undertaken during a 14 days period. Cell preconditioning differed between experimental groups. Immunohistochemical analysis of the regenerated tissue in the meniscus-ring induced by cell loaded composite scaffolds for differentiation and anti-angiogenic factors were performed. Meniscus-pellets and MSC-/MC-based tissue-engineering-products induced angiogenesis. An accelerated vascularization was detected in the group of meniscus-pellets derived from the vascularized zone compared to avascular meniscus-pellets. In terms of cell-based tissue-engineering-products, chondrogenic preconditioning resulted in significantly increased vessel growth. MSC-constructs showed an accelerated angiogenesis. Immunohistochemical evaluation showed a progressive differentiation and lower content for anti-angiogenic endostatin in the precultured group. Preconditioning of MC-/MSC-based tissue-engineering-products is a promising tool to influence the angiogenic potential of tissue-engineering-products and to adapt these properties according to the aimed tissue qualities.

Donor Tissue Preparation for Descemet Membrane Endothelial Keratoplasty: An Updated Review.

To provide an overview of the current literature on donor tissue preparation for Descemet membrane endothelial keratoplasty (DMEK). A comprehensive database search without date restrictions was performed in PubMed and in The Cochrane Library in May, 2017. Keywords included Descemet membrane endothelial keratoplasty, corneal transplantation, graft, harvest, dissection, preparation, endothelial cell, and endothelial cell density. Articles aiming to describe or evaluate a technique for DMEK graft preparation were considered eligible and were included in this review. A graft dissection technique that provides consistent tissue qualities and a low risk of preparation failure is essential for surgeons and eye banks preparing DMEK tissue. Various techniques have been described aiming to facilitate DMEK graft dissection, including manual dissection, pneumatic dissection, and hydrodissection. All show a trend toward a no-touch technique, for example, without direct physical tissue manipulation during tissue harvesting, as a potential ideal approach to minimize graft damage. An overview of the current harvesting techniques available for DMEK may benefit corneal surgeons and eye banks in choosing the best approach for each specific user.

Free flaps in scar treatment.

Introduction:Scar management needs defined concepts and an algorithm to restore functional and aesthetic units. After an unsuccessful conservative treatment, surgical measures provide a vast spectrum of possibilities for remediation. The spectrum of possibilities consists of excision and Z-plasty, regional flaps, vascularized pedicled flaps, tissue expansion, and finally free tissue transfer. Severe scarring and highly destructed tissues with inferior functional and aesthetic units can be effectively treated with radical excision and free flap reconstruction. The complexity of flap architecture and tissue qualities allows for an individualized approach. Specific attention should be paid to the long-term consequences of severe scarring with progressive loss of functionality.Materials and methods:We worked out the most common surgical approaches and treatment algorithm for a stepwise and effective approach. Part of this algorithm is a seven-step surgical approach.Results:This article provides modern plastic and reconstructive surgery concepts with an algorithm for scar management.Discussion:The treatment of scars follows an algorithm with the level of complexity of techniques adjusted to the individual case and the conditions. Disabilities induced by scarring can lead to further functional loss. In these cases, surgical strategies have to be considered.

Perivascular adipose tissue: epiphenomenon or local risk factor?

Obesity is associated with an increased cardiovascular risk, but the mechanisms underlying the link between increased body weight and vascular disease are incompletely understood. Over the past 15 years, perivascular adipose tissue has emerged as active component of the vessel wall involved in vascular homeostasis. However, perivascular adipose tissue can adopt detrimental properties under the influence of obesity and other factors and contribute actively to the pathophysiology of cardiovascular disease. Conversely, changes of the vessel wall may negatively affect perivascular adipose tissue qualities. In this review, we will discuss the recent literature on the possible direct and indirect connections between perivascular fat alterations and cardiovascular pathologies. In addition to clinical evidence on the association between perivascular fat mass and morphology and anthropometric measures of obesity or the reciprocal connection between perivascular fat and cardiometabolic risk factors and disease, special emphasis will be placed on results in rodent and other models and the possible direct contribution of local fat depots to vascular dysfunction, neointima formation or atherosclerosis. We will briefly highlight results from human and murine genome, miRNome and proteome-wide expression analyses of potential candidate mediators involved in its paracrine activities and present data on how the cardiovascular risk factors obesity, age or diabetes, but also the preventive measures weight loss or exercise impact on perivascular expression patterns. A better understanding of this unique adipose tissue depot, its properties and regulatory mechanisms, may create opportunities for novel diagnostic and therapeutic strategies to combat the cardiovascular consequences of increased body weight.

Free-floating epithelial micro-tissue arrays: a low cost and versatile technique

Three-dimensional (3D) tissue models are invaluable tools that can closely reflect the in vivo physiological environment. However, they are usually difficult to develop, have a low throughput and are often costly; limiting their utility to most laboratories. The recent availability of inexpensive additive manufacturing printers and open source 3D design software offers us the possibility to easily create affordable 3D cell culture platforms. To demonstrate this, we established a simple, inexpensive and robust method for producing arrays of free-floating epithelial micro-tissues. Using a combination of 3D computer aided design and 3D printing, hydrogel micro-moulding and collagen cell encapsulation we engineered microenvironments that consistently direct the growth of micro-tissue arrays. We described the adaptability of this technique by testing several immortalised epithelial cell lines (MDCK, A549, Caco-2) and by generating branching morphology and micron to millimetre scaled micro-tissues. We established by fluorescence and electron microscopy that micro-tissues are polarised, have cell type specific differentiated phenotypes and regain native in vivo tissue qualities. Finally, using Salmonella typhimurium we show micro-tissues display a more physiologically relevant infection response compared to epithelial monolayers grown on permeable filter supports. In summary, we have developed a robust and adaptable technique for producing arrays of epithelial micro-tissues. This in vitro model has the potential to be a valuable tool for studying epithelial cell and tissue function/architecture in a physiologically relevant context.

Enhancing Palpation Skills Through the Use of Stereognosis Drills

Context: Musculoskeletal palpation is taught in our athletic training programs as part of the injury evaluation process. However, as palpation skills are taught, the focus is oftentimes on accuracy of surface-anatomy landmarks instead of the ability to discriminate qualitative information such as tissue tone, spasm, or pain response from the soft tissue. Because palpation is foundational for evaluation and intervention, a need exists for further development of this skill. Objective: Provide educators with instructional techniques to enhance palpation skills. Background: Manual medicine techniques are increasingly common in athletic training and require superb palpation and soft tissue discrimination skills. The ability to detect large and small differences in tissue qualities during orthopaedic evaluation can lead to a more accurate assessment as well as enhance manual medicine intervention techniques. Description: We describe 4 activities to enhance palpation skills (coin discrimination, sheet tension, vacuum-immobilizer assembly, and spring-scale compression). Each activity is presented with progressions to improve the foundation of a student's palpation skills and provide advanced training to better refine palpation skills. Clinical Advantage(s): Integrating tasks to improve palpation skills throughout the athletic training curriculum may help improve student confidence, accuracy, and precision while performing patient evaluation and manual medicine interventions. Improved ability to detect and discriminate musculoskeletal pathology can lead to more accurate assessment and efficient intervention techniques. Conclusion(s): Palpation is an essential skill in musculoskeletal evaluation and intervention. With consistent and progressive instruction, this skill can be practiced and refined, improving student confidence and skill application.