Virtual BUILD Research Collaboratory: A biomedical data science training using innovative pedagogy to address structures of racism and inequitable stress for undergraduates of color.

OBJECTIVE: The unprecedented events of 2020 required a pivot in scientific training to better prepare the biomedical research workforce to address global pandemics, structural racism, and social inequities that devastate human health individually and erode it collectively. Furthermore, this pivot had to be accomplished in the virtual environment given the nation-wide lockdown. METHODS: These needs and context led to leveraging of the San Francisco Building Infrastructure Leading to Diversity (SF BUILD) theories of change to innovate a Virtual BUILD Research Collaboratory (VBRC). The purpose of VBRC was to train Black, Indigenous, and people of color (BIPOC) students to apply their unique perspectives to biomedical research. These training activities were evaluated using a pre-post survey design that included both validated and new psychosocial scales. A new scale was piloted to measure culturally relevant pedagogy. RESULTS: VBRC scholars increased science identity on two items: thinking of myself as a scientist (+1point, p = 0.006) and belonging to a community of scientists (+1point, p = 0.069). Overall, scholars perceived stress also decreased over VBRC (-2.35 points, p = 0.02). Post VBRC, scholars had high agency scores (µ = 11.02, Md = 12, range = 6-12, σ = 1.62) and cultural humility scores (µ = 22.11, Md = 23, range = 12-24, σ = 2.71). No notable race/ethnic differences were found in any measures. CONCLUSIONS: Taken together, our innovative approach to data science training for BIPOC in unprecedented times shows promise for better preparing the workforce critically needed to address the fundamental gaps in knowledge at the intersection of public health, structural racism, and biomedical sciences.

Textbook outcomes after oesophagectomy: a single-centre observational study.

BACKGROUND: Textbook outcomes is a composite quality assurance tool assessing the ideal perioperative and postoperative course as a unified measure. Currently, its definition and application in the context of oesophagectomy in Australia is unknown. The aim of this study was to assess the textbook outcomes after oesophagectomy in a single referral centre of Australia and investigate the association between textbook outcomes and patient, tumour, and treatment characteristics. METHODS: An observational study was retrospectively performed on patients undergoing open, laparoscopic, or hybrid oesophagectomy between January 2010 and December 2019 in a single cancer referral centre. A textbook outcome was defined as the fulfillment of 10 criteria: R0 resection, retrieval of at least 15 lymph nodes, no intraoperative complications, no postoperative complications greater than Clavien-Dindo grade III, no anastomotic leak, no readmission to the ICU, no hospital stay beyond 21 days, no mortality within 90 days, no readmission related to the surgical procedure within 30 days from admission and no reintervention related to the surgical procedure. The proportion of patients who met each criterion for textbook outcome was calculated and compared. Selected patient-related parameters (age, gender, BMI, ASA score, CCI score), tumour-related factors (tumour location, tumour histology, AJCC clinical T and N stage and treatment-related factor [neoadjuvant chemotherapy and surgical approach]) were assessed. Disease recurrence and one year survival were also evaluated. RESULTS: 110 patients who underwent oesophagectomy were included. The overall textbook outcome rate was 24%. The difference in rates across the years was not statistically significant. The most achieved textbook outcome parameters were 'no mortality in 90 days' (96%) and 'R0 resection' (89%). The least frequently met textbook outcome parameter was 'no severe postoperative complications' (58%), followed by 'no hospital stays over 21 days' (61%). No significant association was found between patient, tumour and treatment characteristics and the rate of textbook outcome. Tumour recurrence rate and overall long term survival was similar between textbook outcome and non-textbook outcome groups. Patients with R0 resection, no intraoperative complication and a hospital stay less than 21 days had reduced mortality rates. CONCLUSIONS: Textbook outcome is a clinically relevant indicator and was achieved in 24% of patients. Severe complications and a prolonged hospital stay were the key criteria that limited the achievement of a textbook outcome. These findings provide meticulous evaluation of oesophagectomy perioperative care and provide a direction for the utilisation of this concept in identifying and improving surgical and oncological care across multiple healthcare levels.

Financial burden of postoperative complications following oesophagectomy: a scoping review protocol.

INTRODUCTION: The rapid rise in the incidence of oesophageal adenocarcinoma has resulted in an increasing number of patients undergoing oesophagectomy. Although novel surgical techniques are enhancing surgical outcomes, postoperative complications remain pervasive. Despite this, there are limited reviews mapping the cost of postoperative complications following oesophagectomy, and none has compared cost differences between patient groups. Such information would be invaluable in appreciating the financial burden on the healthcare system and serving to guide hospital financing decisions. This scoping review protocol outlines an approach to reviewing the literature to precipitate and inform discussions surrounding financing oesophagectomy procedures as well as funding requirements for upper gastrointestinal surgical units. METHODS AND ANALYSIS: Adhering to the pertinent components of the Preferred Reporting Items for Systematic Review and Meta-Analysis Extension for Scoping Review Protocols guidelines, a systematic exploration will be conducted across electronic databases, including MEDLINE, EMBASE, the Cochrane Library and Econolit, with further reference tracking of eligible studies. This review will encompass studies related to the costs associated with complications following oesophagectomy. All studies published prior to 31 October 2023 are eligible for inclusion. The process of screening and extracting data will be undertaken by two independent reviewers. Subsequently, the amassed data will be pooled and subjected to comprehensive analysis and presented descriptively, using both a mixed methods and a narrative approach. ETHICS AND DISSEMINATION: Ethics approval was not required. The results will be communicated through established professional networks, conference presentations and publication in peer-reviewed journals.

Neck Muscle Coactivation Response to Varied Levels of Mental Workload During Simulated Flight Tasks.

OBJECTIVE: To evaluate neck muscle coactivation across different levels of mental workload during simulated flight tasks. BACKGROUND: Neck pain (NP) is highly prevalent among military aviators. Given the complex nature within the flight environment, mental workload may be a risk factor for NP. This may induce higher levels of neck muscle coactivity, which over time may accelerate fatigue, increase neck discomfort, and affect flight task performance. METHOD: Three counterbalanced mental workload conditions represented by simulated flight tasks modulated by interstimulus frequency and complexity were investigated using the Modifiable Multitasking Environment (ModME). The primary measure was a neck coactivation index to describe the neuromuscular effort of the neck muscles as a system. Additional measures included perceived workload (NASA TLX), subjective discomfort, and task performance. Participants (n = 60; 30M, 30F) performed three test conditions over 1 hr each while seated in a simulated seating environment. RESULTS: Neck coactivation indices (CoA) and subjective neck discomfort corresponded with increasing level of mental workload. Average CoAs for low, medium, and high workloads were: .0278(SD = .0232), .0286(SD = .0231), and .0295(SD = .0228), respectively. NASA TLX mental, temporal, effort, and overall scores also increased with the level of mental workload assigned. For ModME task performance, the overall performance score, monitoring accuracy, and resource management accuracy decreased while reaction times increased with the increasing level of mental workload. Communication accuracy was lowest with the low mental workload but had higher reaction times relative to increasing workload. CONCLUSION: Mental workload affects neck muscle coactivation during combinations of simulated flight tasks within a simulated helicopter seating environment. APPLICATION: The results of this study provide insights into the physical response to mental workload. With increasing multisensory modalities within the work environment, these insights may assist the consideration of physical effects from cognitive factors.

The impact of intraoperative and postoperative fluid balance on complications for transthoracic esophagectomy: a retrospective analysis.

OBJECTIVE: Transthoracic esophagectomy is associated with significant morbidity and mortality. Therefore, it is imperative to optimize perioperative management and minimize complications. In this retrospective analysis, we evaluated the association between fluid balance and esophagectomy complications at a tertiary hospital in Melbourne, Australia, with a particular focus on respiratory morbidity and anastomotic leaks. Cumulative fluid balance was calculated intraoperatively, postoperatively in recovery postoperative day (POD) 0, and on POD 1 and 2. High and low fluid balance was defined as greater than or less than the median fluid balance, respectively, and postoperative surgical complications were graded using the Clavien-Dindo classification. RESULTS: In total, 109 patients, with an average age of 64 years, were included in this study. High fluid balance on POD 0, POD1 and POD 2 was associated with a higher incidence of anastomotic leak (OR 8.59; 95%CI: 2.64-39.0). High fluid balance on POD 2 was associated with more severe complications (of any type) (OR 3.33; 95%CI: 1.4-8.26) and severe pulmonary complications (OR 3.04; 95%CI: 1.27-7.67). For every 1 L extra cumulative fluid balance in POD 1, the odds of a major complication increase by 15%, while controlling for body mass index (BMI) and American Society of Anaesthesiologists (ASA) class. The results show that higher cumulative fluid balance is associated with worsening postoperative outcomes in patients undergoing transthoracic esophagectomy. Restricted fluid balance, especially postoperatively, may mitigate the risk of postoperative complications - however prospective trials are required to establish this definitively.

Disorientation effects, circulating small ribonucleic acid, and genetic susceptibility on static postural stability.

Background: Motion Sickness increases risk of performance deficits and safety of flight concerns. The etiology of motion sickness is poorly understood. Here, we attempted to quantify the physiological effects of motion sickness on static balance and determine the genetic predictors associated with these effects. Methods: 16 subjects underwent a disorientation stimulus to induce motion sickness. Motion sickness susceptibility was identified using the Motion Sickness Susceptibility Questionnaire. Postural balance outcomes were measured using two tasks, and small ribonucleic acid profiles were assessed with blood draws before motion sickness stimulus. Differences in postural sway before and after the stimulus as well as effect modification of susceptibility were assessed. A random forest followed by regression tree analysis was constructed for each postural sway variable to determine top genetic and covariate predictors. Findings: Significant differences existed in mean postural balance responses between before and after stimulus. Individuals with longer stimulus survival experienced a greater (but insignificant) perception of sway, even if not displaying increased sway for all conditions. Circulation small ribonucleic acids were differentially expressed between individuals with long and short stimulus survival, many of these microRNA have purported targets in genes related to vestibular disorders. Interpretation: We found motion sickness produces transient motor dysfunction in a healthy military population. Small ribonucleic acids were differentially expressed between subjects with long and short stimulus survival times.

Postoperative complications and hospital costs following open radical cystectomy: A retrospective study.

OBJECTIVES: To evaluate primarily the relationship between postoperative complications and hospital costs, and secondarily the relationship between postoperative complications and mortality, following radical cystectomy. METHODS: Postoperative complications were retrospectively examined for 147 patients undergoing radical cystectomy at a university hospital between January 2012 and July 2021. Complications were defined and graded using the Clavien-Dindo classification system. In-hospital cost was calculated using an activity-based costing methodology. Regression modelling was used to investigate the relationships among a priori selected perioperative variables, complications, and costs. The effect of complications on postoperative mortality was ascertained using time-dependent coefficients in a Cox proportional hazards regression model. RESULTS: 135 (92%) patients experienced one or more postoperative complications. The medians of hospital cost for patients who experienced no complications and those who experienced complications were $42,796.3 (29,222.9-53,532.5) and $81,050.1 (49,614.8-122,533.6) respectively, p < 0.001. Hospital costs were strongly associated with complication severity: Clavien-Dindo grade II complications increased costs by 45.2% (p < 0.001, 95% CI 19.1%-76.6%), and Clavien-Dindo grade III to V complications increased costs by 107.5% (p < 0.001, 95% CI 52.4%-181.8%). Each additional count of complication and increase in Clavien-Dindo complication grade increased the risk of mortality 1.28-fold (RR = 1.28, p = 0.006, 95% CI 1.08-1.53) and 2.50-fold (RR = 2.50, p = 0.012 95% CI 1.23-5.07) respectively. CONCLUSIONS: These findings demonstrate a high prevalence of complications following cystectomy and significant associated increases in hospital costs and mortality. Postoperative complications are a key target for cost-containment strategies. TRIAL REGISTRATION: Trial Registration: Australian New Zealand Clinical Trials Registry (ACTRN:12622000057785.

Exploring the Interaction Between Head-Supported Mass, Posture, and Visual Stress on Neck Muscle Activation.

OBJECTIVE: Assess neck muscle activity for varying interactions between helmet, posture, and visual stress in a simulated "helo-hunch" posture. BACKGROUND: Military aviators frequently report neck pain (NP). Risk factors for NP include head-supported mass, awkward postures, and mental workload. Interactions between these factors could induce constant low-level muscle activation during helicopter flight and better explain instances of NP. METHOD: Interactions between physical loading (helmet doffed/donned), posture (symmetric/asymmetric), and visual stress (low/high contrast) were studied through neck muscle electromyography (EMG), head kinematics, subjective discomfort, perceived workload, and task performance. Subjects (n = 16) performed eight 30-min test conditions (varied physical loading, posture, and visual stress) while performing a simple task in a simulated "helo-hunch" seating environment. RESULTS: Conditions with a helmet donned had fewer EMG median frequency cycles (which infer motor unit rotation for rest/recovery, where more cycles are better) in the left cervical extensor and left sternocleidomastoid. Asymmetric posture (to the right) resulted in higher normalized EMG activity in the right cervical extensor and left sternocleidomastoid and resulted in less lateral bending compared with neutral across all conditions. Conditions with high visual stress also resulted in fewer EMG cycles in the right cervical extensor. CONCLUSION: A complex interaction exists between the physical load of the helmet, postural stress from awkward postures, and visual stress within a simulated "helo-hunch" seating environment. APPLICATION: These results provide insight into how visual factors influence biomechanical loading. Such insights may assist future studies in designing short-term administrative controls and long-term engineering controls.

In Situ-forming Collagen Hydrogels Crosslinked by Multifunctional Polyethylene Glycol as a Matrix Therapy for Corneal Defects: 2-Month Follow-up In Vivo.

PURPOSE: We recently showed that in situ-forming collagen gels crosslinked through multifunctional polyethylene glycol (PEG) supported corneal epithelialization 7 days after treatment of lamellar keratectomy wounds. In this study, we aimed to evaluate the longer-term regenerative effects of this gel in animals. METHOD: Corneal wound healing was assessed 60 days after lamellar keratectomy and gel treatment using slitlamp examination, optical coherence tomography (OCT), pachymetry, corneal topography, an ocular response analyzer, and tonometry. The corneas were evaluated for the presence of beta-tubulin, cytokeratin 3, zonula occludens-1, and alpha smooth muscle actin (SMA) markers. Gene expression of aldehyde dehydrogenase 3A1 (ALDH3A1), cluster of differentiation 31, CD163, alpha-SMA, hepatocyte growth factor, and fibroblast growth factor 2 (FGF-2) and protein expression of CD44 and collagen VI were evaluated. RESULTS: Intraocular pressure, corneal thickness, and hysteresis for the corneas treated with collagen-PEG gels did not significantly change compared with the saline group. However, placido disk topography revealed greater regularity of the central cornea in the gel-treated group compared to the saline group. The gel-treated group exhibited a lower degree of epithelial hyperplasia than the saline group. Immunohistochemical and gene expression analysis showed that the gel-treated corneas exhibited lower alpha-SMA expression compared with the saline group. CD163 and CD44 were found to be elevated in the saline-treated group compared with normal corneas. CONCLUSIONS: The in situ-forming collagen-PEG gel promoted epithelialization that improved central corneal topography, epithelial layer morphology, and reduced expression of fibrotic and inflammatory biomarkers after 60 days compared to the saline group.

In Situ-Forming Collagen-Hyaluronate Semi-Interpenetrating Network Hydrogel Enhances Corneal Defect Repair.

Purpose: Millions worldwide suffer vision impairment or blindness from corneal injury, and there remains an urgent need for a more effective and accessible way to treat corneal defects. We have designed and characterized an in situ-forming semi-interpenetrating polymer network (SIPN) hydrogel using biomaterials widely used in ophthalmology and medicine. Methods: The SIPN was formed by cross-linking collagen type I with bifunctional polyethylene glycol using N-hydroxysuccinimide ester chemistry in the presence of linear hyaluronic acid (HA). Gelation time and the mechanical, optical, swelling, and degradation properties of the SIPN were assessed. Cytocompatibility with human corneal epithelial cells and corneal stromal stem cells (CSSCs) was determined in vitro, as was the spatial distribution of encapsulated CSSCs within the SIPN. In vivo wound healing was evaluated by multimodal imaging in an anterior lamellar keratectomy injury model in rabbits, followed by immunohistochemical analysis of treated and untreated tissues. Results: The collagen-hyaluronate SIPN formed in situ without an external energy source and demonstrated mechanical and optical properties similar to the cornea. It was biocompatible with human corneal cells, enhancing CSSC viability when compared with collagen gel controls and preventing encapsulated CSSC sedimentation. In vivo application of the SIPN significantly reduced stromal defect size compared with controls after 7 days and promoted multilayered epithelial regeneration. Conclusions: This in situ-forming SIPN hydrogel may be a promising alternative to keratoplasty and represents a step toward expanding treatment options for patients suffering from corneal injury. Translational Relevance: We detail the synthesis and initial characterization of an SIPN hydrogel as a potential alternative to lamellar keratoplasty and a tunable platform for further development in corneal tissue engineering and therapeutic cell delivery.

Local dynamic stability of the trunk after prolonged seating with axial load.

Fatigue from prolonged seating with an axial load on the trunk may impair neuromuscular control and spine stability which may elevate risk of low back pain (LBP) for dynamic tasks following seating. The objective of this study was to assess local dynamic trunk stability using the maximum Lyapunov exponent (λMAX) with corresponding coactivation patterns to understand possible effects from prolonged seating. An increase in λMAX would indicate decreased stability. Twenty participants (10 male, 10 female) performed a controlled, cyclic sagittal flexion task at 40 cycles per minute before and after three hours of seating in a simulated helicopter-seating environment with a weighted vest. A statistically significant decrease was seen in λMAX (bits/s) (Pre-Test = 0.654 ± 0.172; Post-Test = 0.829 ± 0.268, p = 0.002), trunk cumulative coactivation index (unitless/s) (Pre-Test = 1.71 ± 0.97; Post-Test = 1.59 ± 0.96, p = 0.0095), and abdominal activation (normalized) (Pre-Test = 0.46 ± 0.17, Post-Test = 0.41 ± 0.18, p = 0.0146) post-seating exposure. Trunk extension was reduced (∼4°, p = 0.0004) during the post-seating cyclic test with slight corresponding increases in flexion. This study provides evidence of potential effects of fatigue from prolonged seating to neuromuscular control, which may have implications for occupations requiring highly dynamic tasks after prolonged seated postures. Future studies would repeat the tests with dynamic environments (i.e., vibration), test the cyclic flexion protocols with different seating interventions, and continue to test the approach to develop a tool to assess back impairment or intervention effectiveness.

Motion sickness decreases low back function and changes gene expression in military aircrew.

BACKGROUND: Motion sickness and low back disorders are prevalent and debilitating conditions that affect the health, performance, and operational effectiveness of military aircrews. This study explored the effects of a motion sickness stimulus on biomechanical and genetic factors that could potentially be involved in the causal pathways for both disorders. METHODS: Subjects recruited from a military population were exposed to either a mild (n = 12) or aggressive (n = 16) motion sickness stimulus in a Neuro-Otologic Test Center. The independent variable of interest was the motion sickness stimulus exposure (before vs. after), though differences between mild and aggressive stimuli were also assessed. Dependent measures for the study included motion sickness exposure duration, biomechanical variables (postural stability, gait function, low back function, lumbar spine loading), and gene expression. FINDINGS: Seven of twelve subjects experiencing the mild motion sickness stimulus endured the full 30 min in the NOTC, whereas subjects lasted an average of 13.2 (SD 5.0) minutes in the NOTC with the aggressive motion sickness stimulus. Mild motion sickness exposure led to a significant decrease in the postural stability measure of sway area, though the aggressive motion sickness exposure led to a statistically significant increase in sway area. Both stimuli led to decreases in low back function, though the decrease was only statistically significant for the mild protocol. Both stimuli also led to significant changes in gene expression. INTERPRETATION: Motion sickness may alter standing balance, decrease low back function, and lead to changes in the expression of genes with roles in osteogenesis, myogenesis, development of brain lymphatics, inflammation, neuropathic pain, and more. These results may provide preliminary evidence for a link between motion sickness and low back disorders.

Supramolecular host-guest hyaluronic acid hydrogels enhance corneal wound healing through dynamic spatiotemporal effects.

Severe corneal wounds can lead to ulceration and scarring if not promptly and adequately treated. Hyaluronic acid (HA) has been investigated for the treatment of corneal wounds due to its remarkable biocompatibility, transparency and mucoadhesive properties. However, linear HA has low retention time on the cornea while many chemical moieties used to crosslink HA can cause toxicity, which limits their clinical ocular applications. Here, we used supramolecular non-covalent host-guest interactions between HA-cyclodextrin and HA-adamantane to form shear-thinning HA hydrogels and evaluated their impact on corneal wound healing. Supramolecular HA hydrogels facilitated adhesion and spreading of encapsulated human corneal epithelial cells ex vivo and improved corneal wound healing in vivo as an in situ-formed, acellular therapeutic membrane. The HA hydrogels were absorbed within the corneal stroma over time, modulated mesenchymal cornea stromal cell secretome production, reduced cellularity and inflammation of the anterior stroma, and significantly mitigated corneal edema compared to treatment with linear HA and untreated control eyes. Taken together, our results demonstrate supramolecular HA hydrogels as a promising and versatile biomaterial platform for corneal wound healing.

A Simple Inner-Stopper Guarded Trephine for Creation of Uniform Keratectomy Wounds in Rodents.

PURPOSE: Creating controllable, reproducible keratectomy wounds in rodent corneas can be a challenge due to their small size, thickness, and the lack of usual tools available for human eyes such as a vacuum trephine. The purpose of this work is to provide a consistent, reproducible corneal stromal defect in rats using a simple, economical, and customized inner-stopper guarded trephine. METHODS: The inner-stopper guarded trephine is used to induce a circular wound in rat corneas. After trephination, the corneal flap can be removed by manual dissection using a blunt spatula. We used optical coherence topography (OCT) to measure the defect wound depth induced in ex vivo rat eyes. RESULTS: Despite a minor learning curve, this simple device enables depth control, reduces variability of manual keratectomy wound depth in rats, and decreases the risk for corneal perforation during keratectomy. Corneal defect creation was highly reproducible across different researchers and was independent of their surgical training. CONCLUSION: This inner-stopper guarded trephine can be utilized and applied to pre-clinical testing of a wide range of corneal wound healing therapies, including but not limited to biotherapeutics, corneal prosthetics, and regenerative technologies.

Factors influencing early and long-term survival following hip fracture among nonagenarians.

BACKGROUND: The outcomes of nonagenarian patients undergoing orthopaedic surgery are not well understood. We investigated the 30-day mortality after surgical treatment of unilateral hip fracture. The relationship between postoperative complications and mortality was evaluated. METHODS: We performed a single-centre retrospective cohort study of nonagenarian patients undergoing hip fracture surgery over a 6-year period. Postoperative complications were graded according to the Clavien-Dindo classification. Correlation analyses were performed to evaluate the relationship between mortality and pre-specified mortality risk predictors. Survival analyses were assessed using Cox proportional hazards regression modelling. RESULTS: The study included 537 patients. The 30-day mortality rate was 7.4%. The mortality rate over a median follow-up period of 30 months was 18.2%. Postoperative complications were observed in 459 (85.5%) patients. Both the number and severity of complications were related to mortality (p < 0.001). Compared to patients who survived, deceased patients were more frail (p = 0.034), were at higher ASA risk (p = 0.010) and were more likely to have preoperative congestive heart failure (p < 0.001). The adjusted hazard ratio for mortality according to the number of complications was 1.3 (95% CI 1.1, 1.5; p = 0.003). Up to 21 days from admission, any increase in complication severity was associated significantly greater mortality [adjusted hazard ratio: 3.0 (95% CI 2.4, 3.6; p < 0.001)]. CONCLUSION: In a nonagenarian cohort of patients undergoing hip fracture surgery, 30-day mortality was 7.4%, but 30-month mortality rates approached one in five patients. Postoperative complications were independently associated with a higher mortality, particularly when occurring early.

P-selectin antibody treatment after blunt thoracic trauma prevents early pulmonary arterial thrombosis without changes in viscoelastic measurements of coagulation.

INTRODUCTION: Previously, in a murine model of blunt thoracic trauma, we provided evidence of primary pulmonary thrombosis associated with increased expression of the cell adhesion molecule, P-selectin. In this study, mice are treated with P-selectin blocking antibody after injury to investigate the clinical viability of this antibody for the prevention of pulmonary thrombosis. In addition, viscoelastic testing is performed to investigate if P-selectin inhibition has a detrimental impact on normal hemostasis. METHODS: A murine model of thoracic trauma was used. Mice were divided into sham control and experimental injury groups. Thirty minutes after trauma, mice were treated with the following: P-selectin blocking antibody, isotype control antibody, low-dose heparin, high-dose heparin, or normal saline. At 90 minutes, whole blood was collected for characterization of coagulation by viscoelastic coagulation monitor (VCM Vet; Entegrion, Durham, NC). Mean clotting time, clot formation time, clot kinetics (α angle), and maximum clot firmness were compared between each treatment group. RESULTS: Mice that received P-selectin antibody 30 minutes after blunt thoracic trauma had four- to fivefold less (p < 0.001) arterial fibrin accumulation than those that received the isotype control. In both sham and trauma groups, compared with vehicle (normal saline) alone, no statistical difference was noted in any coagulation parameters after injection with P-selectin antibody, isotype control, or low-dose heparin. In addition, blinded histopathological evaluation yielded no difference in hemorrhage scores between injured mice treated with P-selectin blocking antibody and those treated with isotype antibody control. CONCLUSION: This study supports the clinical use of P-selectin blocking antibody for the prevention of pulmonary thrombosis by confirming its efficacy when given after a blunt thoracic trauma. In addition, we demonstrated that the administration of P-selectin antibody does not adversely affect systemic coagulation as measured by viscoelastic testing, suggesting that P-selectin antibody can be safely given during the acute posttraumatic period.

3D Printable, Modified Trephine Designs for Consistent Anterior Lamellar Keratectomy Wounds in Rabbits.

PURPOSE: Our goal is to develop a low-cost tool that can be used to create consistent, partial-thickness defects in rabbit and other large animals with minimal surgical training and that can facilitate pre-clinical testing of lamellar and in situ-forming biosynthetic matrix materials for corneal repair. MATERIALS & METHODS: In this study, three modified trephines were designed to create deep corneal wound defects with consistent depth in large animals. The modified trephines incorporated either 3D-printed parts made from photopolymerizable resins, or custom-cut commercially available Teflon sheets. Wound defects were imaged with optical coherence tomography (OCT), and the depth was analyzed based on the OCT images. RESULTS: The results revealed that an inner-stopper guard trephine had the best performance in creating consistent and precise wound defect depth compared to modified vacuum trephine and custom guard vacuum trephine. A 75% ± 10% cut of the cornea was achieved with the inner-stopper guard trephine. The wound defect depth by created by the inner-stopper guard trephine was independent of the corneal thickness or size of the globes. Although the cut depth of the inner-stopper guard trephine differed by the experience-level of its users, the consistency (standard deviation) of the depth was independent of experience. CONCLUSIONS: Our studies provided three cost-efficient animal trephines that can create corneal wounds of consistent depth by lab researchers without extensive training in keratectomy.

In situ-forming collagen hydrogel crosslinked via multi-functional PEG as a matrix therapy for corneal defects.

Visually significant corneal injuries and subsequent scarring collectively represent a major global human health challenge, affecting millions of people worldwide. Unfortunately, less than 2% of patients who could benefit from a sight-restoring corneal transplant have access to cadaveric donor corneal tissue. Thus, there is a critical need for new ways to repair corneal defects that drive proper epithelialization and stromal remodeling of the wounded area without the need for cadeveric donor corneas. Emerging therapies to replace the need for donor corneas include pre-formed biosynthetic buttons and in situ-forming matrices that strive to achieve the transparency, biocompatibility, patient comfort, and biointegration that is possible with native tissue. Herein, we report on the development of an in situ-forming hydrogel of collagen type I crosslinked via multi-functional polyethylene glycol (PEG)-N-hydroxysuccinimide (NHS) and characterize its biophysical properties and regenerative capacity both in vitro and in vivo. The hydrogels form under ambient conditions within minutes upon mixing without the need for an external catalyst or trigger such as light or heat, and their transparency, degradability, and stiffness are modulated as a function of number of PEG arms and concentration of PEG. In addition, in situ-forming PEG-collagen hydrogels support the migration and proliferation of corneal epithelial and stromal cells on their surface. In vivo studies in which the hydrogels were formed in situ over stromal keratectomy wounds without sutures showed that they supported multi-layered surface epithelialization. Overall, the in situ forming PEG-collagen hydrogels exhibited physical and biological properties desirable for a corneal stromal defect wound repair matrix that could be applied without the need for sutures or an external trigger such as a catalyst or light energy.

Bio-orthogonally crosslinked hyaluronate-collagen hydrogel for suture-free corneal defect repair.

Biomaterials that mimic corneal stroma could decrease the need for donor corneal tissue and could decrease the prevalence of complications associated with corneal transplantation, including infection and rejection. We developed a bio-orthogonally crosslinked hyaluronate-collagen hydrogel which can fill corneal defects in situ without the need for any sutures, initiators, or catalysts. We studied the effects of biorthogonal crosslinking on the light transmittance of the hydrogel, which was greater than 97% water. The transmittance of the optimized hydrogel in the visible light range was over 94%. We also investigated the mechanical properties, refractive index, morphology, biocompatibility, and corneal re-epithelialization capacity of the hyaluronate-collagen hydrogel. Our in vitro, in vivo, and ex vivo results demonstrated that this bio-orthogonally crosslinked hyaluronate-collagen hydrogel has excellent potential as a biomaterial for cornea repair and regeneration.