Online Bayesian optimization of vagus nerve stimulation

Objective.In bioelectronic medicine, neuromodulation therapies induce neural signals to the brain or organs, modifying their function. Stimulation devices capable of triggering exogenous neural signals using electrical waveforms require a complex and multi-dimensional parameter space to control such waveforms. Determining the best combination of parameters (waveform optimization or dosing) for treating a particular patient's illness is therefore challenging. Comprehensive parameter searching for an optimal stimulation effect is often infeasible in a clinical setting due to the size of the parameter space. Restricting this space, however, may lead to suboptimal therapeutic results, reduced responder rates, and adverse effects.Approach. As an alternative to a full parameter search, we present a flexible machine learning, data acquisition, and processing framework for optimizing neural stimulation parameters, requiring as few steps as possible using Bayesian optimization. This optimization builds a model of the neural and physiological responses to stimulations, enabling it to optimize stimulation parameters and provide estimates of the accuracy of the response model. The vagus nerve (VN) innervates, among other thoracic and visceral organs, the heart, thus controlling heart rate (HR), making it an ideal candidate for demonstrating the effectiveness of our approach.Main results.The efficacy of our optimization approach was first evaluated on simulated neural responses, then applied to VN stimulation intraoperatively in porcine subjects. Optimization converged quickly on parameters achieving target HRs and optimizing neural B-fiber activations despite high intersubject variability.Significance.An optimized stimulation waveform was achieved in real time with far fewer stimulations than required by alternative optimization strategies, thus minimizing exposure to side effects. Uncertainty estimates helped avoiding stimulations outside a safe range. Our approach shows that a complex set of neural stimulation parameters can be optimized in real-time for a patient to achieve a personalized precision dosing.

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.

Improving the time to ileostomy closure following an anterior resection for rectal cancer in the UK

AIM

Delayed closure of ileostomy following an anterior resection for rectal cancer in the UK is common. The aims of this study were (i) to investigate the variation in patient pathways between hospitals, (ii) to identify the key learning points from units with the shortest time to closure and (iii) to develop guidance for a pathway to minimize delay in ileostomy closure.

METHOD

This was a mixed methods study. Thirty-eight colorectal units in the UK completed a short online survey. Nine colorectal units in Wales filled in an additional, expanded version of the survey. Semi-structured interviews were performed with clinicians from the six best performing units in terms of timely ileostomy closure. The optimal pathway suggested is based on the best evidence available and the Association of Coloproctology of Great Britain and Ireland guidelines.

RESULTS

Qualitative analysis revealed that 5% of units (n = 2) have a local target time for ileostomy closure. Of all units, 90% (n = 34) would consider implementing a pathway if guidelines were developed. In-depth interviews highlighted the importance of a multidisciplinary approach, a dedicated coordinator to facilitate timely booking, and consensus on whether closure should be performed before or after adjuvant chemotherapy.

CONCLUSION

There is a lack of national guidance in timing of contrast studies and ileostomy closure. Key aspects to consider are better information at consent regarding stoma closure timing, a dedicated person to track patients and the planning of contrast studies at discharge from initial surgery. With a dedicated approach closure of ileostomy within 10-12 weeks is feasible for most units.

Haplotyping the Potato Psyllid (Hemiptera: Triozidae) and the Associated Pathogenic Bacterium 'Candidatus Liberibacter solanacearum' in Non-crop Alternative Hosts in Southern Idaho

Zebra chip, is a potato disease associated with the bacterium 'Candidatus Liberibacter solanacearum' (Lso) and vectored by the potato psyllid, Bactericera cockerelli Šulc. Potato psyllids are native to North America, where four haplotypes have been described. They are able to colonize a wide range of solanaceous species, crops, and weeds. The epidemiology of zebra chip disease is still poorly understood and might involve the different haplotypes of psyllids as well as two haplotypes of Lso. As several perennial weeds have been recognized as potential host for potato psyllids and Lso, a yearly monitoring of several patches of bittersweet nightshade (Solanum dulcamara) and field bindweed (Convolvulus arvensis) located in the potato-growing region of southern Idaho was conducted from 2013 to 2017, to gain insight into psyllid dynamics in non-potato hosts and Lso presence in the fields. Potato psyllids caught on each host were individually tested for Lso, and a subset were haplotyped based on the CO1 gene, along with the haplotyping of Lso in positive samples. On bittersweet nightshade, the Northwestern haplotype was numerically dominant, with around 2.7% of psyllids found to be carrying either Lso haplotype A or B, suggesting a limited role in zebra chip persistence, which has infected Idaho fields at a low occurrence since the 2012 outbreak. Field bindweed was found to be a transient, non-overwintering host for potato psyllid of Northwestern, Western and Central haplotypes late in the season, suggesting minor, if any, role in persistence of Lso and field infestation by potato psyllids.

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.

Associations of the Potato Psyllid and "Candidatus Liberibacter solanacearum" in Idaho with the Noncrop Host Plants Bittersweet Nightshade and Field Bindweed

Zebra chip disease (ZC) in potato (Solanum tuberosum L. [Polemoniales: Solanaceae]) can produce unmarketable tubers with striped necrotic patterns. ZC is associated with the bacterium "Candidatus Liberibacter solanacearum" (Lso), which is transmitted by the potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae). Potato psyllids are associated with numerous noncrop host plants, especially from the Solanaceae and Convolvulaceae; however, the contribution and importance of these hosts to ZC epidemiology in potato is poorly understood. To clarify seasonal phenologies on two such hosts, we sampled potato psyllids from bittersweet nightshade, Solanum dulcamara L. (Polemoniales: Solanaceae), and field bindweed, Convolvulus arvensis L. (Polemoniales: Convolvulaceae), over 2013-2017 and 2014-2016, respectively. Adult psyllids were sampled using yellow sticky traps, vacuum samples, and beat sheets. Each psyllid was tested for the presence of Lso by polymerase chain reaction. Psyllids often were abundant on bittersweet nightshade during May to November, with low numbers observed over each winter. Vacuum samples often captured more psyllids than other methods. Lso incidence was low except during 2016 when vacuum samples showed 23% incidence. Potato psyllids regularly overwinter on bittersweet nightshade in Idaho; however, differences in psyllid populations and Lso incidence from those found on potato suggest that this host plant may only partly contribute to infestations in potato. Observations of psyllids on field bindweed suggest only transient visits to this plant around potato harvest, with no evidence of overwintering and no Lso detected. Further work is needed to clarify how potato psyllid use of other noncrop hosts is related to their abundance in Idaho potato fields.

Phenology of the Potato Psyllid, Bactericera cockerelli (Hemiptera: Triozidae), and "Candidatus Liberibacter solanacearum" in Commercial Potato Fields in Idaho

Zebra chip disease (ZC) is an emerging disease of potato in which tubers are produced with striped necrotic patterns that make them unmarketable. ZC is associated with the bacterium "Candidatus Liberibacter solanacearum" (Lso), which is transmitted by the potato psyllid, Bactericera cockerelli (Šulc; Hemiptera: Triozidae). First found in Idaho during 2011, ZC now contributes to increased production costs each season via additional insecticide sprays. To clarify the extent and severity of the threat of ZC in Idaho, we sampled potato psyllids in commercial potato fields across the state over four growing seasons (2012-2015). All life stages of psyllids were sampled using a combination of methods (yellow sticky traps, vacuum samples, and leaf samples), and adult psyllids were tested for the presence of Lso by Polymerase Chain Reaction (PCR). Abundance of potato psyllids initially increased gradually over each growing season, then exhibited a sharp late-season rise and a sharp decline as most fields were being harvested. Abundance of psyllids was higher at warmer, lower elevation sites, but infestation onset did not differ between growing regions. Fewer psyllids were collected in vacuum samples than in sticky trap samples. Nymphs and eggs were found only late season and during years with high abundance of adults. Overall incidence of Lso was similar among all years but one. The results presented here clarify our understanding of the seasonal phenology of potato psyllids and Lso in Idaho potato fields and will aid in developing integrated management strategies against this important pest of potato.

Adjuvant chemotherapy for rectal cancer: Is it needed?

Adjuvant chemotherapy has become a standard treatment of advanced rectal cancer in the West. The benefits of adjuvant chemotherapy after surgery alone have been well established. However, controversy surrounds the use adjuvant chemotherapy in patients who received preoperative chemoradiotherapy, despite it being recommended by a number of international guidelines. Results of recent multicentre randomised control trials showed no benefit of adjuvant chemotherapy in terms of survival and rates of distant metastases. However, concerns exist regarding the quality of the studies including inadequate staging modalities, out-dated chemotherapeutic regimens and surgical approaches and small sample sizes. It has become evident that not all the patients respond to adjuvant chemotherapy and more personalised approach should be employed when considering the benefits of adjuvant chemotherapy. The present review discusses the strengths and weaknesses of the current evidence-base and suggests improvements for future studies.

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.

Abstract 2051: Three-dimensional in vivo photoacoustic tracking of targeted nanoparticles in a pancreatic cancer model

The use of targeted gold nanoparticles (AuNPs) has shown tremendous promise in the early detection and improved therapy of cancer. Successful development and implementation of these new theranostic approaches, however, depends on sufficient transvascular migration and specific accumulation of AuNPs to extravascular tumor tissue. This study utilized photoacoustic (PA) imaging to track - in three dimensions and through 24 hours - the extravasation and accumulation of targeted AuNPs in a subcutaneous murine model of prostate cancer. AuNPs (nanorods; 760-nm peak) targeting the Luteinizing-hormone-releasing hormone receptor were systemically injected into three mice bearing PC-3 human prostate cancer tumors; as a control, three additional mice were injected with PEGylated AuNPs. For all particle-tracking studies, multi-wavelength (680, 760, 800, 920, & 940 nm), volumetric (spherical volume with 25.6-mm diameter) PA imaging was conducted at pre-injection, post-injection, 15-min, 60-min, 240-min, and 24-hr time points; the imaging volume contained the tumor and the spleen (control). Following imaging, tumors were excised and inductively coupled plasma mass spectrometry (ICP-MS) of samples and two-photon imaging of histological sections was performed to confirm AuNP accumulation and diffusion, respectively. Volumetric PA perfusion assessment was then conducted by monitoring the wash-out of indocyanine green (ICG) in near real-time (0.25 Hz for 180 s post-injection). All PA imaging studies were performed on the Nexus 128 preclinical imaging system (Endra Inc., Ann Arbor, MI). Spectral unmixing of the multi-wavelength PA data was achieved to segment AuNPs and deoxy-/oxyhemoglobin (i.e. for local hypoxia assessment). Accumulation and extravasation data of the targeted AuNPs in the tumor were then compared to tumor perfusion data, PA-derived tumor hypoxia data, PEGylated AuNP accumulation data in the tumor, AuNP accumulation data in the spleen, and ICP-MS/histological analysis. Results of the study establish that volumetric PA imaging with multi-wavelength unmixing is able to track nanoparticle accumulation and extravasation throughout an in vivo tumor model. The location and relative degree of particle accumulation was also found to correlate with PA-based perfusion and vascularity assessment. This study demonstrates that volumetric PA imaging has the spatiotemporal resolution and sensitivity to track extravasation of AuNPs in an in vivo tumor model. This in vivo tracking ability - along with concurrent PA-based perfusion and hypoxia mapping - could be of significant benefit in understanding and improving nanoparticle targeting for the diagnosis and treatment of cancer.

Citation Format: Richard Bouchard, Tatiana Wolfe, Michael Thornton, Timothy Morgan, Trevor Mitcham, Shanta Bhattarai, Jonathan Grant, Jihyoun Lee, John Hazle, Sunil Krishnan. Three-dimensional in vivo photoacoustic tracking of targeted nanoparticles in a pancreatic cancer model. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2051. doi:10.1158/1538-7445.AM2014-2051

The unfolded protein response regulator GRP78 is a novel predictive biomarker in colorectal cancer

Adjuvant fluoropyrimidine-based (5-FU) chemotherapy is a mainstay of treatment for colorectal cancer (CRC), but only provides benefit for a subset of patients. To improve stratification we examined (for the first time in CRC), whether analysis of GRP78 expression provides a predictive biomarker and performed functional studies to examine the role of GRP78 in sensitivity to 5-FU. 396 CRC patient samples were collected in a prospective uniform manner and GRP78 expression was determined by immunohistochemistry on tissue microarrays using a well-validated antibody. Expression was correlated with clinicopathological parameters and survival. The role of GRP78 in 5-FU sensitivity was examined in CRC cells using siRNA, drug inhibition and flow cytometry. GRP78 expression was significantly elevated in cancer tissue (p < 0.0001), and correlated with depth of invasion (p = 0.029) and stage (p = 0.032). Increased overall 5-year survival was associated with high GRP78 expression (p = 0.036). Patients with stage II cancers treated by surgery alone, with high GRP78 also had improved survival (71% v 50%; p = 0.032). Stage III patients with high GRP78 showed significant benefit from adjuvant chemotherapy (52% vs. 28%; p = 0.026), whereas patients with low GRP78 failed to benefit (28% vs. 32%; p = 0.805). Low GRP78 was an independent prognostic indicator of reduced overall 5-year survival (p = 0.004; HR = 1.551; 95%CI 1.155-2.082). In vitro, inhibition of GRP78 reduces apoptosis in response to 5-FU in p53 wild-type cells. GRP78 expression may provide a simple additional risk stratification to inform the adjuvant treatment of CRC and future studies should combine analysis with determination of p53 status.

Combining highly multiplexed PCR with semiconductor-based sequencing for rapid cancer genotyping

There is growing demand for routine identification of actionable mutations in clinical cancer specimens. Genotyping platforms must provide rapid turnaround times and work effectively with limited amounts of formalin-fixed, paraffin-embedded (FFPE) tissue specimens that often yield poor quality DNA. We describe semiconductor-based sequencing of DNA from FFPE specimens using a single-tube, multiplexed panel of 190 amplicons targeting 46 cancer genes. With just 10 ng of input DNA, average read depths of 2000× can be obtained in 48 hours, with >95% of the reads on target. A validation set of 45 FFPE tumor specimens containing 53 point mutations previously identified with a mass spectrometry-based genotyping platform, along with 19 indels ranging from 4 to 63 bp, was used to evaluate assay performance. With a mutant allele ratio cutoff of 8%, we were able to achieve 100% sensitivity (95% CI = 97.3% to 100.0%) and 95.1% specificity (95% CI = 91.8% to 98.0%) of point mutation detection. All indels were visible by manual inspection of aligned reads; 6/9 indels ≤12 bp long were detected by the variant caller software either exactly or as mismatched nucleotides within the indel region. The rapid turnaround time and low input DNA requirements make the multiplex PCR and semiconductor-based sequencing approach a viable option for mutation detection in a clinical laboratory.

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.

Abstract LB-410: Targeted resequencing of genes frequently mutated in esophageal adenocarcinoma using highly multiplexed Ion Torrent AmpliSeqTM technology and semiconductor sequencing

Introduction: Whole genome and whole exome sequencing by large collaborative research groups is providing us with an unprecedented view of the mutations that occur in cancer. Identifying clinically-relevant and actionable mutations however remains a challenge that will most likely be met by individual groups focused on specific clinical questions and scenarios. Such studies will rely on targeted resequencing of selected genes in large numbers of well-annotated clinical specimens. These specimens are most often formalin-fixed and paraffin-embedded (FFPE) and some of the most valuable samples are small biopsies or fine needle aspirates (FNA's). Translational and clinical researchers require rapid and flexible resequencing approaches that are compatible with the small amounts of highly degraded nucleic acids derived from these challenging samples. Materials & Methods: Using Illumina whole exome sequence data from &gt;60 esophageal adenocarcinoma (EAC) specimens, we identified a set of 20 genes that are frequently mutated in this tumor. PCR amplicons no larger than 140bp were designed to cover all exons from these genes, using the Ion Torrent AmpliSeqTM Designer pipeline. Primers were pooled for a 1285-plex multiplex PCR preamplification step starting with 1-20ng of input DNA from both FFPE and frozen tissue and the resulting amplicon products were used to generate sequencing libraries. Semiconductor sequencing was performed on the Ion Personal Genome MachineTM (PGMTM) sequencer. Metrics evaluated included reads on target, base accuracy, uniform coverage of bases and sequencing base read depth. Mutations detected in EAC samples were compared between the two sequencing platforms. Data from dysplastic and metaplastic esophageal biopsies are now being generated to identify mutations that occur in the development of EAC. Results: 1285 PCR primer pairs were designed that covered 66103bp of the coding region of the 20 target genes. Sequencing data covered &gt;99% with at least 100 reads indicating minimal drop-out during preamplification. Average base read depth was &gt;1900X and no significant differences were observed between FFPE and frozen tissue derived DNA. Initial studies demonstrate 100% concordance of mutations (n=42) detected in the 20 target genes and mutant allele frequencies are highly correlated between the two sequencing approaches (slope =0.96; R2 =0.85; range 4-78%). Conclusion: We have used the Ion Torrent AmpliSeqTM technology to detect mutations in EAC specimens and precursor lesions with high sensitivity and accuracy. The flexible primer design pipeline combined with AmpliSeqTM technology provides a fast and easy approach to targeted resequencing in particularly challenging clinical specimens including FFPE biopsies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-410. doi:1538-7445.AM2012-LB-410

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.

Management and outcome of colorectal anastomotic leaks

PURPOSE

Anastomotic leak is a devastating complication of an intestinal anastomosis. Optimal management and outcome is not routinely described, and much of our knowledge relies upon historical data. We wished to examine the management and outcome of anastomotic leaks on a colorectal surgery unit in the twenty-first century.

METHOD

A retrospective audit of all patients who had a colorectal anastomotic leak between January 2002 and December 2008 in a large university teaching hospital. Data collected included patient characteristics, primary diagnosis, mode of diagnosis and time to diagnosis of anastomotic leak, inpatient management, morbidity and mortality, permanent stoma rate, use of hospital resources.

RESULTS

Thirty patients (16 male, 14 female), with a median age of 60 years (range 25-84 years), had an anastomotic leak. The median time to presentation of clinically suspected leaks was 12 days (range 3-56 days). Fourteen patients required reoperation, with ten needing the anastomosis take down. Average hospital stay was 40 days. The permanent stoma rate following a rectal anastomotic leak was 27% and 57.1% from a colonic leak. Overall mortality in this series was 27%. Mortality was higher after leak from a colonic anastomosis than after leak from a rectal anastomosis (43.8% vs. 7.1%, respectively).

CONCLUSIONS

Anastomotic leaks are not detected until late in the post-operative period and are associated with a high mortality. Demand on hospital resources is high. In this series, patients who leaked after a colonic anastomosis had a higher mortality and permanent stoma rate than after leaks from a rectal anastomosis.

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.

Case report: an unusual case of sudden cardiovascular collapse in an elderly adult

In our report we describe a case of foreign body aspiration leading to arrest. The patient's resuscitation was remarkable for the development of a large pneumothorax and atelectasis of the right lung. Aspiration was suspected and early bronchoscopy was performed. A large grape was found to be obstructing the right main stem bronchus and was retrieved using a bronchoscopic snare. In this case early intervention allowed the removal of the intact grape with subsequent re-expansion of the lung. The technique used for retrieval is described.

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.