Mechanical load applied by Intraosseous Transcutaneous Amputation Prosthesis (ITAP) during walking on level and sloped treadmill: A case study

This proof of concept study presents a method to collect and analyse kinetic data from one participant with a transfemoral amputation fitted with a percutaneous osseointegrated implant walking on a level and sloped treadmill. We describe the construction of and results from a bespoke wireless six axis load cell built into one participant's prosthetic assembly. The load cell does not clinically compromise the participant in any way and is an initial milestone in the development of a light-weight wireless load cell for use with percutaneous osseointegrated implants. In this case, it is the first time that kinetic data from a participant fitted with an Intraosseous Transcutaneous Amputation Prosthesis has been published. We propose that the data can be used to model the load transfer to the host bone, with several clinically significant applications. The raw dynamic data are made available and quasi-static load cases for each functional phase of gait are presented. Peak forces obtained in the medio-lateral (X), cranio-caudal (Y) and antero-posterior (Z) axes over level ground respectively were -243.8 N (0.24 BW), 1321.5 N (1.31 BW) and -421.8 N (0.42 BW); uphill were -141.0 N (0.14 BW), 1604.2 N (1.59 BW), -498.1 N (0.49 BW); downhill were -206.0 N (0.20 BW), 1103.9 N (1.09 BW), -547.2 N (0.54 BW). The kinetics broadly followed able bodied gait patterns with some gait strategies consistent in participants with other implant designs or prosthetic socket connections, for example offloading the artificial limb downhill.

Pre-hospital ECPR in an Australian metropolitan setting: a single-arm feasibility assessment-The CPR, pre-hospital ECPR and early reperfusion (CHEER3) study

INTRODUCTION

Survival from refractory out of hospital cardiac arrest (OHCA) without timely return of spontaneous circulation (ROSC) utilising conventional advanced cardiac life support (ACLS) therapies is dismal. CHEER3 was a safety and feasibility study of pre-hospital deployed extracorporeal membrane oxygenation (ECMO) during cardiopulmonary resuscitation (ECPR) for refractory OHCA in metropolitan Australia.

METHODS

This was a single jurisdiction, single-arm feasibility study. Physicians, with pre-existing ECMO expertise, responded to witnessed OHCA, age < 65 yrs, within 30 min driving-time, using an ECMO equipped rapid response vehicle. If pre-hospital ECPR was undertaken, patients were transported to hospital for investigations and therapies including emergent coronary catheterisation, and standard intensive care (ICU) therapy until either cardiac and neurological recovery or palliation occurred. Analyses were descriptive.

RESULTS

From February 2020 to May 2023, over 117 days, the team responded to 709 "potential cardiac arrest" emergency calls. 358 were confirmed OHCA. Time from emergency call to scene arrival was 27 min (15-37 min). 10 patients fulfilled the pre-defined inclusion criteria and all were successfully cannulated on scene. Time from emergency call to ECMO initiation was 50 min (35-62 min). Time from decision to ECMO support was 16 min (11-26 min). CPR duration was 46 min (32-62 min). All 10 patients were transferred to hospital for investigations and therapy. 4 patients (40%) survived to hospital discharge neurologically intact (CPC 1/2).

CONCLUSION

Pre-hospital ECPR was feasible, using an experienced ECMO team from a single-centre. Overall survival was promising in this highly selected group. Further prospective studies are now warranted.

Evaluating the Use of CT-Derived Lung Volumes in Donor-Recipient Lung Size Matching for Lung Transplantation in Patients With Interstitial Lung Disease and/or Idiopathic Pulmonary Fibrosis

PURPOSE

This study aims to assess the efficacy of current measurement strategies for lung sizing and the feasibility of future use of computed tomography (CT)-derived lung volumes to predict a donor-recipient lung size match during bilateral lung transplants.

METHODS

We reviewed the data of 62 patients who underwent bilateral lung transplantation for interstitial lung disease and/or idiopathic pulmonary fibrosis from 2018 to 2019. Data for recipients was retrieved from the department's transplant database and medical records, and the donor's data was retrieved from the DonorNet. The data included demographic data, lung heights, measured total lung capacity (TLC) from plethysmography for recipients and estimated TLC for donors, clinical data, and CT-derived lung volumes in both pre- and post-transplant recipients. The post-transplant CT-derived lung volume in recipients was used as a surrogate for donor lung CT volumes due to inadequate or poor donor CT data. Computed tomography-derived lung volumes were calculated using thresholding, region growing, and cutting techniques on Computer-Aided Design and Mimics (Materialise NV, Leuven, Belgium) programs. Preoperative CT-derived lung volumes in recipients were compared with the plethysmography TLC, Frustum Model, and donor-predicted TLC. The ratio of the recipient's pre-and postoperative CT-derived volumes, the ratio of preoperative CT-derived lung volume, and donor-estimated TLC were studied to detect a correlation with 1-year outcomes.

RESULTS

The recipient preoperative CT-derived volume correlated with the recipient preoperative plethysmography TLC (Pearson correlation coefficient [PCC] of 0.688) and with the recipient Frustum model volume (PCC of 0.593). The recipient postoperative CT-derived volume correlated with the recipient's postoperative plethysmography TLC (PCC of 0.651). There was no statistically significant correlation between recipients' CT-derived pre- or postoperative volume with donor-estimated TLC. The ratio of preoperative CT-derived volume to donor-estimated TLC correlated inversely with the length of ventilation (P value = .0031). The ratio of postoperative CT-derived volume to preoperative CT-derived volume correlated inversely with delayed sternal closure (P = .0039). No statistically significant correlations were found in evaluating outcomes related to lung oversizing in the recipient (defined as a postoperative to preoperative CT-derived lung volume ratio of >1.2).

CONCLUSIONS

Generating CT-derived lung volumes is a valid and convenient method for evaluating lung volumes for transplantation in patients with ILD and/or IPF. Donor-estimated TLC should be interpreted carefully. Further studies should derive donor lung volumes from CT scans for a more accurate evaluation of lung size matching.

Cordon screen: A cordon-based congestion pricing policy evaluation method for U.S. cities

Global trends toward urbanization will exacerbate traffic congestion, delays in economic productivity, and air pollution issues for growing cities. Traffic congestion pricing is one method available to help ameliorate these concerns. New York City is on the verge of implementing a cordon-based traffic congestion pricing policy around its central business district. For budget-constrained municipalities, evaluating implementation of such policy could be costly. This article proposes a sketch-planning methodology, called Cordon Screen, for major U.S. cities to evaluate the net income, traffic mitigation, and avoided pollution emissions from cordon-based traffic congestion pricing. This method relies on national datasets and limited user-specific data inputs, along with a range of user-selectable assumptions informed by academic literature to deliver order-of-magnitude results. The numerous limitations of this method are acceptable for preliminary policy evaluation to determine if greater financial investment to obtain more accurate results is justified. The Denver metropolitan area is used to demonstrate Cordon Screen capabilities, with mid-range assumption results suggesting the policy is most effective at generating net income and increasing vehicle speeds on major interstates. For Denver, the policy is comparably less effective at reducing air pollution and increasing speeds on minor roadways. Validation against early implementation results from the London cordon are acceptable. However, users should discount revenue generation projections. Choice of cordon area may be the most difficult obstacle when using the Cordon Screen. With refinement, Cordon Screen could serve as a low-cost, open-source planning evaluation tool for growing and congested U.S. cities.Implications: As global urbanization trends continue, impacted local governments will be looking to explore policies to mitigate traffic congestion and reduce environmental emissions. Internationally, cordon-based traffic congestion pricing has been implemented in London, Singapore, and several other large cities. In America, New York City is implementing cordon-based congestion pricing around its central business district to reduce traffic and environmental emissions. Financial resource constraints, exacerbated by the COVID-19 pandemic, may limit the ability for local governments to invest in studying new policy options. The Cordon Screen method detailed in the manuscript presents a low-cost, open-source approach to assessing the potential benefits of cordon-based traffic congestion policy. The method utilizes national datasets to minimize user-specific data requirements and allows users to toggle between a range of values to test sensitivities to key assumptions. For example, emissions reductions are highly sensitive to how drivers respond to tolling. In this example, sensitivity testing enables users to understand how policy design can impact air quality goals. The Cordon Screen approach presented provides a strong platform for future stakeholder deliberation, refinement, and implementation.

Viral variant-resolved wastewater surveillance of SARS-CoV-2 at national scale

SARS-CoV-2 surveillance by wastewater-based epidemiology is poised to provide a complementary approach to sequencing individual cases. However, robust quantification of variants and de novo detection of emerging variants remains challenging for existing strategies. We deep sequenced 3,413 wastewater samples representing 94 municipal catchments, covering >59% of the population of Austria, from December 2020 to February 2022. Our system of variant quantification in sewage pipeline designed for robustness (termed VaQuERo) enabled us to deduce the spatiotemporal abundance of predefined variants from complex wastewater samples. These results were validated against epidemiological records of >311,000 individual cases. Furthermore, we describe elevated viral genetic diversity during the Delta variant period, provide a framework to predict emerging variants and measure the reproductive advantage of variants of concern by calculating variant-specific reproduction numbers from wastewater. Together, this study demonstrates the power of national-scale WBE to support public health and promises particular value for countries without extensive individual monitoring.

Activated and nonactivated MSCs increase survival in humanized mice after acute liver injury through alcohol binging

The ability of the liver to regenerate after injury makes it an ideal organ to study for potential therapeutic interventions. Mesenchymal stem cells (MSCs) possess self-renewal and differentiation properties, as well as anti-inflammatory properties that make them an ideal candidate for therapy of acute liver injury. The primary aim of this study is to evaluate the potential for reversal of hepatic injury using human umbilical cord-derived MSCs. Secondary aims include comparison of various methods of administration as well as comparison of activated versus nonactivated human umbilical cord stem cells. To induce liver injury, humanized mice were fed high-cholesterol high-fat liquid diet with alcohol binge drinking. Mice were then treated with either umbilical cord MSCs, activated umbilical cord MSCs, or a placebo and followed for survival. Blood samples were obtained at the end of the binge drinking and at the time of death to measure alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. Histology of all mouse livers was reported at time of death. Activated MSCs that were injected intravenously, intraperitoneally, or both routes had superior survival compared with nonactivated MSCs and with placebo-treated mice. AST and ALT levels were elevated in all mice before treatment and improved in the mice treated with stem cells. Conclusion: Activated stem cells resulted in marked improvement in survival and in recovery of hepatic chemistries. Activated umbilical cord MSCs should be considered an important area of investigation in acute liver injury.

If the public can vaccinate, why not students? Review of a student nurse placement in a mass vaccination centre

Delivery of the COVID-19 vaccine has been made possible in part through the use of mass vaccination centres (MVCs). The primary legal framework underpinning the MVC programme is a national protocol enabling registered and non-registered healthcare workers to contribute to the safe and effective administration of the vaccine. The national protocol provided a vehicle for an innovative supervised student nurse placement within an MVC in south Wales. This placement, for undergraduate pre-registration student nurses, formed part of a service improvement project. Through student feedback prior to, and following, the short placement, the learning was unequivocal in terms of knowledge and skills acquisition related to safe and effective vaccine administration, with students providing clear feedback on the positive nature of the placement experience. A placement within an MVC offers a rich educational experience for student nurses, which as yet appears to be underutilised across the UK.

Transitioning Behavioral Healthcare in Louisiana Through the COVID-19 Pandemic: Policy and Practice Innovations to Sustain Telehealth Expansion

A statewide COVID-19 quarantine order forced an abrupt shift for Louisiana’s behavioral health providers who provide mental health and substance abuse treatment services. The Center for Evidence to Practice conducted a study of this unprecedented shift to better understand the disruption and continuation of care during early statewide adoption of telemental health. The Center performed a mixed-method assessment including a series of focus groups and key informant interviews followed by a survey of over 300 responding providers. Over 85% of providers reported sustaining behavioral health services using a variety of telemental health strategies. While traditional referral networks and client volume were significantly disrupted, temporary relaxation of Medicaid regulatory and reimbursement policies appeared to be a key facilitator of telemental health adoption and continued services. Shifting to telemental health relied on provider’s quick adaptations, engaging clients with a hybrid of teleconferencing platforms, calls/texts, and socially-distanced in-person visits. Larger multi-clinician providers and evidence-based practice (EBP) providers were better equipped to support the adoption of telemental health. Rural and EBPs providers disproportionately discontinued services. Although many practitioners viewed the original COVID-19 pandemic as a short-lived condition, the recent emergence of Delta and other variants has shown the impact on the BH care system may be lasting. Flexibility across policies and a variety of telemental health platforms are keys to telehealth adaptation. However, the contraction of the client base raises concerns of increasing disparities among vulnerable and hard-to-reach populations if telemental health becomes a sustained approach in response to future COVID-19 variants.

Use of the margin of stability to quantify stability in pathologic gait - a qualitative systematic review

BACKGROUND

The Margin of Stability (MoS) is a widely used objective measure of dynamic stability during gait. Increasingly, researchers are using the MoS to assess the stability of pathological populations to gauge their stability capabilities and coping strategies, or as an objective marker of outcome, response to treatment or disease progression. The objectives are; to describe the types of pathological gait that are assessed using the MoS, to examine the methods used to assess MoS and to examine the way the MoS data is presented and interpreted.

METHODS

A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Guidelines (PRISMA) in the following databases: Web of Science, PubMed, UCL Library Explore, Cochrane Library, Scopus. All articles measured the MoS of a pathologically affected adult human population whilst walking in a straight line. Extracted data were collected per a prospectively defined list, which included: population type, method of data analysis and model building, walking tasks undertaken, and interpretation of the MoS.

RESULTS

Thirty-one studies were included in the final review. More than 15 different clinical populations were studied, most commonly post-stroke and unilateral transtibial amputee populations. Most participants were assessed in a gait laboratory using motion capture technology, whilst 2 studies used instrumented shoes. A variety of centre of mass, base of support and MoS definitions and calculations were described.

CONCLUSIONS

This is the first systematic review to assess use of the MoS and the first to consider its clinical application. Findings suggest the MoS has potential to be a helpful, objective measurement in a variety of clinically affected populations. Unfortunately, the methodology and interpretation varies, which hinders subsequent study comparisons. A lack of baseline results from large studies mean direct comparison between studies is difficult and strong conclusions are hard to make. Further work from the biomechanics community to develop reporting guidelines for MoS calculation methodology and a commitment to larger baseline studies for each pathology is welcomed.

Complications and functional outcomes after ileo-anal pouch excision-a systematic review of 14 retrospective observational studies

PURPOSE

The ileo-anal pouch (IAP) has been the gold standard procedure for maintenance of bowel continuity after panproctocolectomy for ulcerative colitis, familial adenomatous polyposis or hereditary non-polyposis colorectal cancer. However, the IAP has an estimated failure rate of 13% at 10 years post-procedure (Tulchinsky et al., Ann Surg 238(2):229-34, 2003), which can result in pouch excision (P.E.). This systematic review aims to synthesise all the available studies reporting post-operative outcomes of P.E. and its impact on patient quality of life (QoL), when available, which have not previously been summarised.

METHODS

PubMed, Embase, Medline and the Cochrane library databases were searched with terms 'Pouch AND excision' OR 'Pouch AND removal' OR 'Pouch AND remove' OR 'IAP AND excision'. All studies reporting post-operative morbidity, mortality or functional outcomes in patients who had P.E. were included. Studies with < 5 patients, non-English studies and conference abstracts were excluded.

RESULTS

14 studies comprising 1601 patients were included. Overall complications varied from 18 to 63% with the most common being persistent perineal sinus (9-40%) or surgical site infection (wound-2 to 30%; intra-abdominal collection-3 to 24%). The mortality rate was between 0.58 and 1.4%. QoL is generally lower in P.E. patients compared to the normal population across various QoL measures and P.E. patients often had urinary and sexual dysfunction post-operatively.

CONCLUSIONS

There is a substantial incidence of complications after P.E.; however, there is no evidence describing QoL pre- and post-P.E. Further longitudinal research comparing QoL in patients undergoing P.E. and other treatment options such as indefinite diversion is required to definitively assess QoL post-procedure.

Secondary organic aerosol formation from evaporated biofuels: comparison to gasoline and correction for vapor wall losses

With an ongoing interest in displacing petroleum-based sources of energy with biofuels, there is a need to measure and model the formation and composition of secondary organic aerosol (SOA) from organic compounds present in biofuels. We performed chamber experiments to study SOA formation from four recently identified biofuel molecules and mixtures and commercial gasoline under high NOx conditions: diisobutylene, cyclopentanone, an alkylfuran mixture, and an ethanol-to-hydrocarbon (ETH) mixture. Cyclopentanone and diisobutylene had a significantly lower potential to form SOA compared to commercial gasoline, with SOA mass yields lower than or equal to 0.2%. The alkylfuran mixture had an SOA mass yield (1.6%) roughly equal to that of gasoline (2.0%) but ETH had an average SOA mass yield (11.5%) that was six times higher than that of gasoline. We used a state-of-the-science model to parameterize or simulate the SOA formation in the chamber experiments while accounting for the influence of vapor wall losses. Simulations performed with vapor wall losses turned off and at atmospherically relevant conditions showed that the SOA mass yields were higher than those measured in the chamber at the same photochemical exposure and were also higher than those estimated using a volatility basis set that was fit to the chamber data. The modeled SOA mass yields were higher primarily because they were corrected for vapor wall losses to the Teflon® chamber.

Glomerular endothelial cell heterogeneity in Alport syndrome

Glomerular endothelial cells (GEC) are a crucial component of the glomerular physiology and their damage contributes to the progression of chronic kidney diseases. How GEC affect the pathology of Alport syndrome (AS) however, is unclear. We characterized GEC from wild type (WT) and col4α5 knockout AS mice, a hereditary disorder characterized by progressive renal failure. We used endothelial-specific Tek-tdTomato reporter mice to isolate GEC by FACS and performed transcriptome analysis on them from WT and AS mice, followed by in vitro functional assays and confocal and intravital imaging studies. Biopsies from patients with chronic kidney disease, including AS were compared with our findings in mice. We identified two subpopulations of GEC (dim^tdT and bright^tdT) based on the fluorescence intensity of the Tek^tdT signal. In AS mice, the bright^tdT cell number increased and presented differential expression of endothelial markers compared to WT. RNA-seq analysis revealed differences in the immune and metabolic signaling pathways. In AS mice, dim^tdT and bright^tdT cells had different expression profiles of matrix-associated genes (Svep1, Itgβ6), metabolic activity (Apom, Pgc1α) and immune modulation (Apelin, Icam1) compared to WT mice. We confirmed a new pro-inflammatory role of Apelin in AS mice and in cultured human GEC. Gene modulations were identified comparable to the biopsies from patients with AS and focal segmental glomerulosclerosis, possibly indicating that the same mechanisms apply to humans. We report the presence of two GEC subpopulations that differ between AS and healthy mice or humans. This finding paves the way to a better understanding of the pathogenic role of GEC in AS progression and could lead to novel therapeutic targets.

Robust RNA-Seq of aRNA-amplified single cell material collected by patch clamp

Most single cell RNA sequencing protocols start with single cells dispersed from intact tissue. High-throughput processing of the separated cells is enabled using microfluidics platforms. However, dissociation of tissue results in loss of information about cell location and morphology and potentially alters the transcriptome. An alternative approach for collecting RNA from single cells is to re-purpose the electrophysiological technique of patch clamp recording. A hollow patch pipette is attached to individual cells, enabling the recording of electrical activity, after which the cytoplasm may be extracted for single cell RNA-Seq ("Patch-Seq"). Since the tissue is not disaggregated, the location of cells is readily determined, and the morphology of the cells is maintained, making possible the correlation of single cell transcriptomes with cell location, morphology and electrophysiology. Recent Patch-Seq studies utilizes PCR amplification to increase amount of nucleic acid material to the level required for current sequencing technologies. PCR is prone to create biased libraries - especially with the extremely high degrees of exponential amplification required for single cell amounts of RNA. We compared a PCR-based approach with linear amplifications and demonstrate that aRNA amplification (in vitro transcription, IVT) is more sensitive and robust for single cell RNA collected by a patch clamp pipette.

In Vivo Developmental Trajectories of Human Podocyte Inform In Vitro Differentiation of Pluripotent Stem Cell-Derived Podocytes

The renal corpuscle of the kidney comprises a glomerular vasculature embraced by podocytes and supported by mesangial myofibroblasts, which ensure plasma filtration at the podocyte-generated slit diaphragm. With a spectrum of podocyte-expressed gene mutations causing chronic disease, an enhanced understanding of podocyte development and function to create relevant in vitro podocyte models is a clinical imperative. To characterize podocyte development, scRNA-seq was performed on human fetal kidneys, identifying distinct transcriptional signatures accompanying the differentiation of functional podocytes from progenitors. Interestingly, organoid-generated podocytes exhibited highly similar, progressive transcriptional profiles despite an absence of the vasculature, although abnormal gene expression was pinpointed in late podocytes. On transplantation into mice, organoid-derived podocytes recruited the host vasculature and partially corrected transcriptional profiles. Thus, human podocyte development is mostly intrinsically regulated and vascular interactions refine maturation. These studies support the application of organoid-derived podocytes to model disease and to restore or replace normal kidney functions.

Co-optimization of Heavy-Duty Fuels and Engines: Cost Benefit Analysis and Implications

Heavy-duty vehicles require expensive aftertreatment systems for control of emissions such as particulate matter (PM) and nitrogen oxides (NO_x) to comply with stringent emission standards. Reduced engine-out emissions could potentially alleviate the emission control burden, and thus bring about reductions in the cost associated with aftertreatment systems, which translates into savings in vehicle ownership. This study evaluates potential reductions in manufacturing and operating costs of redesigned emission aftertreatment systems of line-haul heavy-duty diesel vehicles (HDDVs) with reduced engine-out emissions brought about by co-optimized fuel and engine technologies. Three emissions reduction cases representing conservative, medium, and optimistic engine-out emission reduction benefits are analyzed, compared to a reference case: the total costs of aftertreatment systems (TCA) of the three cases are reduced to $11,400(1.63 ¢/km), $9,100 (1.30 ¢/km), and $8,800 (1.26 ¢/km), respectively, compared to $12,000 (1.71 ¢/km) for the reference case. The largest potential reductions result from reduced diesel exhaust fluid (DEF) usage due to lower NO_x emissions. Downsizing aftertreatment devices is not likely, because the sizes of devices are dependent on not only engine-out emissions, but also other factors such as engine displacement. Sensitivity analysis indicates that the price and usage of DEF have the largest impacts on TCA reduction.

Abstract 1726: Structure-function analysis of retinoblastoma tumor suppressor protein in human cone precursors

Background: The retinoblastoma protein, pRB, is a key cell cycle governor that is functionally impaired in most cancers, but its mechanism of suppressing tumorigenesis in a tumor cell-of-origin has not been characterized. This study aims to define pRB structural features and corresponding cellular functions that suppress cone precursor (CP) proliferation, likely the first step in retinoblastomagenesis.

Method: Intact human fetal retinae were co-transduced with lentiviruses to knockdown endogenous pRB and ectopically express wild type or structure-based substitution mutant pRBs. The ectopically expressed pRB mutants had selectively impaired interactions with E2F transactivation domains (ΔG), with the E2F1 “marked box” domain (ΔS), or with the LxCxE protein interaction motif (ΔL). At day 12-75 post-infection, transduced retinae were analyzed by quantitative immunofluorescence staining of Ki67/EdU, pRB and CP marker L/M-opsin.

Results: In intact retina, pRB knockdown induced cell cycle re-entry of L/M-opsin+ postmitotic cone precursors, whereas those reconstituted with wild type pRB did not express Ki67 indicative of a block to cell cycle entry. Unexpectedly, all three mutants (pRB-ΔG, -ΔL, and -ΔS) were able to block cell cycle re-entry when expressed at the high-normal range the of endogenous pRB. However, at the low-normal expression level, ectopic wild type but not mutant pRBs suppressed proliferation.

Conclusion: All three surface targeted mutants (pRB-ΔG, ΔL, and ΔS) retain partial ability to suppress cone precursor cell cycle entry. This may be attributed to the presence of multiple independent cell cycle inhibitory functions. These findings suggest that pRB-mediated regulation of E2F-responsive cell cycle genes, interactions with LxCxE motif-containing proteins, and EZH2 mediated repression of repetitive elements are individually dispensable for suppressing aberrant cone precursor proliferation.

Citation Format: Sijia Wang, Brendan Grubbs, Matthew Thornton, David Cobrinik. Structure-function analysis of retinoblastoma tumor suppressor protein in human cone precursors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1726.

Neural Crest Cell Implantation Restores Enteric Nervous System Function and Alters the Gastrointestinal Transcriptome in Human Tissue-Engineered Small Intestine

Acquired or congenital disruption in enteric nervous system (ENS) development or function can lead to significant mechanical dysmotility. ENS restoration through cellular transplantation may provide a cure for enteric neuropathies. We have previously generated human pluripotent stem cell (hPSC)-derived tissue-engineered small intestine (TESI) from human intestinal organoids (HIOs). However, HIO-TESI fails to develop an ENS. The purpose of our study is to restore ENS components derived exclusively from hPSCs in HIO-TESI. hPSC-derived enteric neural crest cell (ENCC) supplementation of HIO-TESI establishes submucosal and myenteric ganglia, repopulates various subclasses of neurons, and restores neuroepithelial connections and neuron-dependent contractility and relaxation in ENCC-HIO-TESI. RNA sequencing identified differentially expressed genes involved in neurogenesis, gliogenesis, gastrointestinal tract development, and differentiated epithelial cell types when ENS elements are restored during in vivo development of HIO-TESI. Our findings validate an effective approach to restoring hPSC-derived ENS components in HIO-TESI and may implicate their potential for the treatment of enteric neuropathies.

Cartilage rings contribute to the proper embryonic tracheal epithelial differentiation, metabolism, and expression of inflammatory genes

The signaling cross talk between the tracheal mesenchyme and epithelium has not been researched extensively, leaving a substantial gap of knowledge in the mechanisms dictating embryonic development of the proximal airways by the adjacent mesenchyme. Recently, we reported that embryos lacking mesenchymal expression of Sox9 did not develop tracheal cartilage rings and showed aberrant differentiation of the tracheal epithelium. Here, we propose that tracheal cartilage provides local inductive signals responsible for the proper differentiation, metabolism, and inflammatory status regulation of the tracheal epithelium. The tracheal epithelium of mesenchyme-specific Sox9^Δ/Δ mutant embryos showed altered mRNA expression of various epithelial markers such as Pb1fa1, surfactant protein B (Sftpb), secretoglobulin, family 1A, member 1 (Scgb1a1), and trefoil factor 1 (Tff1). In vitro tracheal epithelial cell cultures confirmed that tracheal chondrocytes secrete factors that inhibit club cell differentiation. Whole gene expression profiling and ingenuity pathway analysis showed that the tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), and transforming growth factor-β (TGF-β) signaling pathways were significantly altered in the Sox9 mutant trachea. TNF-α and IFN-γ interfered with the differentiation of tracheal epithelial progenitor cells into mature epithelial cell types in vitro. Mesenchymal knockout of Tgf-β1 in vivo resulted in altered differentiation of the tracheal epithelium. Finally, mitochondrial enzymes involved in fat and glycogen metabolism, cytochrome c oxidase subunit VIIIb (Cox8b) and cytochrome c oxidase subunit VIIa polypeptide 1 (Cox7a1), were strongly upregulated in the Sox9 mutant trachea, resulting in increases in the number and size of glycogen storage vacuoles. Our results support a role for tracheal cartilage in modulation of the differentiation and metabolism and the expression of inflammatory-related genes in the tracheal epithelium by feeding into the TNF-α, IFN-γ, and TGF-β signaling pathways.

Rac1 modulates mammalian lung branching morphogenesis in part through canonical Wnt signaling

Lung branching morphogenesis relies on a number of factors, including proper epithelial cell proliferation and differentiation, cell polarity, and migration. Rac1, a small Rho GTPase, orchestrates a number of these cellular processes, including cell proliferation and differentiation, cellular alignment, and polarization. Furthermore, Rac1 modulates both noncanonical and canonical Wnt signaling, important pathways in lung branching morphogenesis. Culture of embryonic mouse lung explants in the presence of the Rac1 inhibitor (NSC23766) resulted in a dose-dependent decrease in branching. Increased cell death and BrdU uptake were notably seen in the mesenchyme, while no direct effect on the epithelium was observed. Moreover, vasculogenesis was impaired following Rac1 inhibition as shown by decreased Vegfa expression and impaired LacZ staining in Flk1-Lacz reporter mice. Rac1 inhibition decreased Fgf10 expression in conjunction with many of its associated factors. Moreover, using the reporter lines TOPGAL and Axin2-LacZ, there was an evident decrease in canonical Wnt signaling in the explants treated with the Rac1 inhibitor. Activation of canonical Wnt pathway using WNT3a or WNT7b only partially rescued the branching inhibition. Moreover, these results were validated on human explants, where Rac1 inhibition resulted in impaired branching and decreased AXIN2 and FGFR2b expression. We therefore conclude that Rac1 regulates lung branching morphogenesis, in part through canonical Wnt signaling. However, the exact mechanisms by which Rac1 interacts with canonical Wnt in human and mouse lung requires further investigation.

Evidence for the involvement of fibroblast growth factor 10 in lipofibroblast formation during embryonic lung development

Lipid-containing alveolar interstitial fibroblasts (lipofibroblasts) are increasingly recognized as an important component of the epithelial stem cell niche in the rodent lung. Although lipofibroblasts were initially believed merely to assist type 2 alveolar epithelial cells in surfactant production during neonatal life, recent evidence suggests that these cells are indispensable for survival and growth of epithelial stem cells during adulthood. Despite increasing interest in lipofibroblast biology, little is known about their cellular origin or the molecular pathways controlling their formation during embryonic development. Here, we show that a population of lipid-droplet-containing stromal cells emerges in the developing mouse lung between E15.5 and E16.5. This is accompanied by significant upregulation, in the lung mesenchyme, of peroxisome proliferator-activated receptor gamma (master switch of lipogenesis), adipose differentiation-related protein (marker of mature lipofibroblasts) and fibroblast growth factor 10 (previously shown to identify a subpopulation of lipofibroblast progenitors). We also demonstrate that although only a subpopulation of total embryonic lipofibroblasts derives from Fgf10(+) progenitor cells, in vivo knockdown of Fgfr2b ligand activity and reduction in Fgf10 expression lead to global reduction in the expression levels of lipofibroblast markers at E18.5. Constitutive Fgfr1b knockouts and mutants with conditional partial inactivation of Fgfr2b in the lung mesenchyme reveal the involvement of both receptors in lipofibroblast formation and suggest a possible compensation between the two receptors. We also provide data from human fetal lungs to demonstrate the relevance of our discoveries to humans. Our results reveal an essential role for Fgf10 signaling in the formation of lipofibroblasts during late lung development.

Transvaginal repair of recurrent pouch-vaginal fistula

AIM

Pouch-vaginal fistula is an uncommon but unpleasant complication. The chance of successful repair with various surgical procedures is around 50% and the early promise of collagen button plugs was not followed by good long-term results. We report a series of patients who underwent transvaginal repair of pouch-vaginal fistula after failed collagen plugs accompanied by a video to show the operative technique.

METHOD

Patients were identified from a prospectively maintained database. Patient demographics, operation notes, complications and ultimate outcome were recorded.

RESULTS

Eleven patients, each of whom had previously undergone an attempt to close the fistula with a collagen button plug, underwent transvaginal repair. Nine (81%) were successful at a median follow-up of 14 (6-56) months. The remaining two patients reported symptomatic improvement.

CONCLUSION

Pouch-vaginal fistula can be successfully closed by the transvaginal technique after a failed button plug procedure.

Single-cell gene expression profiles define self-renewing, pluripotent, and lineage primed states of human pluripotent stem cells

Pluripotent stem cells display significant heterogeneity in gene expression, but whether this diversity is an inherent feature of the pluripotent state remains unknown. Single-cell gene expression analysis in cell subsets defined by surface antigen expression revealed that human embryonic stem cell cultures exist as a continuum of cell states, even under defined conditions that drive self-renewal. The majority of the population expressed canonical pluripotency transcription factors and could differentiate into derivatives of all three germ layers. A minority subpopulation of cells displayed high self-renewal capacity, consistently high transcripts for all pluripotency-related genes studied, and no lineage priming. This subpopulation was characterized by its expression of a particular set of intercellular signaling molecules whose genes shared common regulatory features. Our data support a model of an inherently metastable self-renewing population that gives rise to a continuum of intermediate pluripotent states, which ultimately become primed for lineage specification.

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Single-cell transcript profiles characteristic of distinct substates of pluripotency

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Prospective isolation of substate with high self-renewal, no lineage priming

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Self-renewing subpopulation marked by expression of specific ligands and receptors

Eosinophil peroxidase induces the expression and function of acid-sensing ion channel-3 in allergic rhinitis: in vitro evidence in cultured epithelial cells

BACKGROUND

Acid-sensing ion channels (ASIC) are a family of acid-activated ligand-gated cation channels. As tissue acidosis is a feature of inflammatory conditions, such as allergic rhinitis (AR), we investigated the expression and function of these channels in AR.

OBJECTIVES

The aim of the study was to assess expression and function of ASIC channels in the nasal mucosa of control and AR subjects.

METHODS

Immunohistochemical localization of ASIC receptors and functional responses to lactic acid application were investigated. In vitro studies on cultured epithelial cells were performed to assess underlying mechanisms of ASIC function.

RESULTS

Lactic acid at pH 7.03 induced a significant rise in nasal fluid secretion that was inhibited by pre-treatment with the ASIC inhibitor amiloride in AR subjects (n = 19). Quantitative PCR on cDNA isolated from nasal biopsies from control and AR subjects demonstrated that ASIC-1 was equally expressed in both populations, but ASIC-3 was significantly more highly expressed in AR (P < 0.02). Immunohistochemistry confirmed significantly higher ASIC-3 protein expression on nasal epithelial cells in AR patients than controls (P < 0.01). Immunoreactivity for EPO+ eosinophils in both nasal epithelium and submucosa was more prominent in AR compared with controls. A mechanism of induction of ASIC-3 expression relevant to AR was suggested by the finding that eosinophil peroxidase (EPO), acting via ERK1/2, induced the expression of ASIC-3 in epithelial cells. Furthermore, using a quantitative functional measure of epithelial cell secretory function in vitro, EPO increased the air-surface liquid depth via an ASIC-dependent chloride secretory pathway.

CONCLUSIONS

This data suggests a possible mechanism for the observed association of eosinophils and rhinorrhoea in AR and is manifested through enhanced ASIC-3 expression.

Hard choices: a qualitative study of influences on the treatment decisions made by advanced lung cancer patients

OBJECTIVE

Most patients with non-small cell lung cancer (NSCLC) present with an incurable, advanced disease, and treatment decisions may be hard. This study explored the factors that influence patients' choice of treatment during the oncologist-patient consultation.

DESIGN

Semi-structured interviews conducted within 1 month of a consultation with an oncologist.

PARTICIPANTS

Five patients newly diagnosed with incurable NSCLC and facing a treatment decision following a consultation with an oncologist.

SETTING

A regional oncology unit in the UK.

RESULTS

Some of the participants who opted for chemotherapy had made a decision before seeing the oncologist, presented with fewer symptoms, had been more active in seeking information before the consultation, and were willing to accept the risk of side effects. Participants opting for radiotherapy were not willing to accept the risk of side effects for the possibility of a small survival gain and instead focused on symptom relief.

CONCLUSION

Some participants sought information before the consultation from various formal and informal sources. This may undermine the oncologist-patient consultation as the information may be incomplete or inaccurate. Patients vary in their willingness to accept risks for small potential gains. More research is required into methods to communicate the extent of the risks of treatment. The Clinical Nurse Specialist performed a valuable role for the patients and was seen as a trusted source of information.

Effective awake thoracic epidural anesthetic for major abdominal surgery in two high-risk patients with severe pulmonary disease--a case report

Awake thoracic epidural anaesthesia as the sole anaesthetic technique was successfully employed for two high risk surgical patients with chronic obstructive pulmonary disease undergoing abdominal surgery. The procedure was tolerated well and the anaesthetic technique which has been shown to reduce intra-operative and post-operative cardiac, respiratory and gastrointestinal complications, may have significantly contributed to the prompt, complication free recovery experienced by both patients. We report two cases of awake major abdominal surgery in two high-risk surgical patients with severe pulmonary disease, performed effectively under thoracic epidural anaesthesia as a sole technique. The first case was an elective open sigmoid colectomy in a sixty one year old cancerous patient with chronic obstructive pulmonary disease [COPD] and recent thoracotomy for a wedge resection of a bronchial adenocarcinoma [pT1NoMx]. The second case was an emergency open cholecystectomy in an adult patient with end-stage COPD. Reviewing the literature, no similar cases were reported recently.

A low oxygen consumption pneumatic ventilator for emergency construction during a respiratory failure pandemic

The UK influenza pandemic plan predicts up to 750 000 additional deaths with hospitals prioritising patients against inadequate resources. We investigated three prototype low‐cost, gas‐efficient, pneumatic ventilators in a test lung model at different compliance and rate settings. Mean (SD) oxygen consumption was 0.913 (0.198) and 1.119 (0.267) l.min⁻¹ at tidal volumes of 500 ml and 700 ml respectively. Values of F_Io₂ increased marginally as lung compliance reduced, reflecting the increased ventilator workload and consequent increased enrichment of breathing gas by waste oxygen from the pneumatic mechanism. We also demonstrated that a stable nitric oxide concentration could be delivered by this design following volumetric principles. It is possible to make a gas‐efficient ventilator costing less than £200 from industrial components for use where oxygen is available at 2‐4 bar, with no pressurised air or electrical requirements. Such a device could be mass‐produced for crises characterised by an overwhelming demand for mechanical ventilation and a limited oxygen supply.

Benefits of activity and virtual reality based balance exercise programmes for adults with traumatic brain injury: Perceptions of participants and their caregivers

OBJECTIVE

To explore multi-dimensional benefits of exercise participation perceived by adults with traumatic brain injury (TBI) and their caregivers.

METHODS

Adults (n=27, aged 18-66) with moderate or severe TBI 6 months or more earlier participated in focus groups following 6 weeks of an activity-based (ABE) or a virtual reality (VR) delivered balance exercise programme. Family members and care providers participated in separate focus groups. Perceptions related to programme participation as well as balance confidence and lower extremity function were extracted from focus group verbatim and quantitative scales, respectively.

OUTCOMES

Benefits in three domains, psychosocial, physical and programme, were identified from transcription and analyses of focus group verbatim. Improvements were noted in balance confidence and function in both groups. Substantially greater enthusiasm and knowledge was expressed by participants in the VR group and their caregivers.

CONCLUSIONS

Both exercise programmes offered benefits in addition to improved balance. The VR participants had greater improvements on quantitative measures and provided more comments expressing enjoyment and improved confidence. Applications in terms of community reintegration and quality of life are discussed.

Genome-wide pharmacogenetic investigation of a hepatic adverse event without clinical signs of immunopathology suggests an underlying immune pathogenesis

One of the major goals of pharmacogenetics is to elucidate mechanisms and identify patients at increased risk of adverse events (AEs). To date, however, there have been only a few successful examples of this type of approach. In this paper, we describe a retrospective case-control pharmacogenetic study of an AE of unknown mechanism, characterized by elevated levels of serum alanine aminotransferase (ALAT) during long-term treatment with the oral direct thrombin inhibitor ximelagatran. The study was based on 74 cases and 130 treated controls and included both a genome-wide tag single nucleotide polymorphism and large-scale candidate gene analysis. A strong genetic association between elevated ALAT and the MHC alleles DRB1(*)07 and DQA1(*)02 was discovered and replicated, suggesting a possible immune pathogenesis. Consistent with this hypothesis, immunological studies suggest that ximelagatran may have the ability to act as a contact sensitizer, and hence be able to stimulate an adaptive immune response.

Non-conventional uses of the Aintree Intubating Catheter in management of the difficult airway

We present 14 cases, of which three have been previously reported, in which non-conventional use was made of the Aintree Intubating Catheter (AIC). In seven cases the AIC was used via a ProSeal Laryngeal mask airway (PLMA). Two patients had anticipated difficult intubation, two unexpected difficult intubation and two required rescue of an obstructed airway prior to AIC-assisted intubation. In two cases of tracheal stenosis the AIC was used as a 'long narrow tracheal tube' during fibre-optic intubation: the AIC facilitated passage through the narrowed trachea and smooth railroading of a tracheal tube. In two cases the AIC was used in an awake patient. In three cases the AIC was used successfully despite gross laryngeal oedema. In three cases attempted AIC deployment failed: two patients had undergone radiotherapy to the mouth and PLMA placement failed; in the third, supraglottic oedema prevented visualisation of the larynx. The AIC via an LMA Classic was successful in one of these cases. In all cases where the larynx was visualised the AIC was rapidly successful without complications. In eight cases the anaesthetist had no experience of the technique outside workshops. These cases demonstrate general utility of the technique and successful use of the AIC via the PLMA, in awake patients, as an adjunct to fibre-optic intubation and in patients with an oedematous larynx. Finally, cases where the combination of the PLMA and AIC was unsuccessful demonstrate the technique, like many, is not always successful.

Outcomes of intervention programs using flatscreen virtual reality

Virtual reality (VR) has the potential to offer experiences which are engaging and rewarding. In VR, the focus is shifted from the person's efforts in producing a movement or completing a task to that of interaction with the virtual environment. We have found that participants place value and meaning on and enjoy the activities programmed. Virtual reality interventions have been shown to improve cognitive function and concentration through an individual's interaction with a pleasant activity. Importantly, the enjoyment experienced while working with VR may increase the level of participation. In addition to generating realistic situations for testing, intervention and collection of data, the provision of immediate and positive feedback through VR has been shown to increase self esteem and empowerment. We will report outcomes from several intervention and feasibility trials using a flat screen virtual reality system with survivors of traumatic brain injury, community living older adults and children with spastic cerebral palsy. Gross motor movements were elicited through various game-like VR applications without the need for head-mounted displays or other peripherals. The impact of VR exercise participation ranged from improvements in clinical measures of functional balance and mobility, time on task, as well as participant and care provider perceptions of enjoyment, independence and confidence. Although still preliminary, our data suggest that simple applications of virtual reality have significant impacts on physical and psychosocial variables. Possibilities for and benefits of home and community-based access to virtual reality based programs will be explored.

ICP34.5 deleted herpes simplex virus with enhanced oncolytic, immune stimulating, and anti-tumour properties

Herpes simplex virus type-1 (HSV1) in which the neurovirulence factor ICP34.5 is inactivated has been shown to direct tumour-specific cell lysis in several tumour models. Such viruses have also been shown to be safe in Phase I clinical trials by intra-tumoral injection in glioma and melanoma patients. Previous work has used serially passaged laboratory isolates of HSV1 which we hypothesized may be attenuated in their lytic capability in human tumour cells as compared to more recent clinical isolates. To produce ICP34.5 deleted HSV with enhanced oncolytic potential, we tested two clinical isolates. Both showed improved cell killing in all human tumour cell lines tested compared to a laboratory strain (strain 17+). ICP34.5 was then deleted from one of the clinical isolate strains (strain JS1). Enhanced tumour cell killing with ICP34.5 deleted HSV has also been reported by the deletion of ICP47 by the up-regulation of US11 which occurs following this mutation. Thus to further improve oncolytic properties, ICP47 was removed from JS1/ICP34.5-. As ICP47 also functions to block antigen processing in HSV infected cells, this mutation was also anticipated to improve the immune stimulating properties of the virus. Finally, to provide viruses with maximum oncolytic and immune stimulating properties, the gene for human or mouse GM-CSF was inserted into the JS1/34.5-/47- vector backbone. GM-CSF is a potent immune stimulator promoting the differentiation of progenitor cells into dendritic cells and has shown promise in clinical trials when delivered by a number of means. Combination of GM-CSF with oncolytic therapy may be particularly effective as the necrotic cell death accompanying virus replication should serve to effectively release tumour antigens to then induce a GM-CSF-enhanced immune response. This would, in effect, provide an in situ, patient-specific, anti-tumour vaccine. The viruses constructed were tested in vitro in human tumour cell lines and in vivo in mice demonstrating significant anti-tumour effects. These were greatly improved compared to viruses not containing each of the modifications described. In vivo, both injected and non-injected tumours showed significant shrinkage or clearance and mice were protected against re-challenge with tumour cells. The data presented indicate that JS1/ICP34.5-/ICP47-/GM-CSF acts as a powerful oncolytic agent which may be appropriate for the treatment of a number of solid tumour types in man.

A randomised comparison of a foot pump and low-molecular-weight heparin in the prevention of deep-vein thrombosis after total knee replacement

Patients who undergo total knee replacement (TKR)are at high risk of venous thromboembolism. Low-molecular-weight heparins (LMWH) are the most suitable chemical prophylactic agents but there are some uncertainties about their safety and effectiveness. The foot pump offers an alternative.

We randomised 229 patients undergoing primary, unilateral TKR to receive either the A-V Impulse foot pump or enoxaparin, a LMWH. Ascending venography was undertaken between the sixth and eighth postoperative day in 188 patients without knowledge of the randomisation category. The prevalence of venographic deep-vein thrombosis was 58% (57/99) in the foot-pump group and 54% (48/89) in the LMWH group which was not statistically significant. There were four cases of proximal thrombi and two of fatal pulmonary emboli in the foot-pump group and none in the LMWH group. There were fewer haemorrhagic complications and soft-tissue effects in the foot-pump group.

We conclude that the neither method provides superior prophylaxis.

A randomised comparison of a foot pump and low-molecular-weight heparin in the prevention of deep-vein thrombosis after total knee replacement

Patients who undergo total knee replacement (TKR) are at high risk of venous thromboembolism. Low-molecular-weight heparins (LMWH) are the most suitable chemical prophylactic agents but there are some uncertainties about their safety and effectiveness. The foot pump offers an alternative. We randomised 229 patients undergoing primary, unilateral TKR to receive either the A-V Impulse foot pump or enoxaparin, a LMWH. Ascending venography was undertaken between the sixth and eighth postoperative day in 188 patients without knowledge of the randomisation category. The prevalence of venographic deep-vein thrombosis was 58% (57/99) in the foot-pump group and 54% (48/89) in the LMWH group which was not statistically significant. There were four cases of proximal thrombi and two of fatal pulmonary emboli in the foot-pump group and none in the LMWH group. There were fewer haemorrhagic complications and soft-tissue effects in the foot-pump group. We conclude that the neither method provides superior prophylaxis.

Therapeutic embolization of the genicular arteries for recurrent hemarthrosis after total knee arthroplasty

The case of a recurrent hemarthrosis initially presenting 30 months after a total knee arthroplasty in a patient on lifelong warfarin is described. Angiography was used to aid in the diagnosis, and therapeutic selective embolization of the superior genicular arteries was performed with satisfactory clinical results.

Type I laryngeal cleft: late presentation

Laryngeal cleft anomalies are rare congenital defects of the posterior laryngotracheal wall that usually present with a history of recurrent respiratory tract infections during the early neonatal period. Presentation of type I clefts can be subtle and subsequently can result in late diagnosis or indeed failure to present. We report on the case of a type I laryngeal cleft presenting with a history of recurrent lower respiratory tract infections and severe gastro-oesophageal reflux disease, at 19 years of age. This is the oldest documented initial presentation of a congenital laryngeal cleft, and emphasizes the importance of maintaining a suspicion of the diagnosis into early adulthood. We further highlight the role of gastro-oesophageal reflux disease in the presentation of laryngeal clefts.