Swine Lung Research Articles

Mesenchymal stem cell treatment is associated with decreased perfusate concentration of interleukin-8 during ex vivo perfusion of donor lungs after 18-hour preservation

Ex vivo lung perfusion (EVLP) presents a unique therapeutic opportunity to administer mesenchymal stromal cells (MSCs) to lung grafts before transplantation. We sought to determine the optimal route and dose of viable human umbilical cord-derived MSCs to be delivered into ex vivo-perfused damaged swine lungs, and to measure their effect on concentration of growth factors and inflammatory mediators. Pig lungs were conventionally retrieved, cold preserved for 18 hours, and perfused normothermically ex vivo for 12 hours. Physiologic data were recorded. No cells were administered to a control group of animals (n = 5). To examine the routes of administration, lungs were administered 50 × 106 MSCs endobronchially (n = 3) or via the pulmonary artery (n = 3). To determine the doses, a dose-escalation study was performed wherein lungs were administered 50 × 106 (n = 3), 150 × 106 (n = 5) and 300 × 106 (n = 3) MSCs via the pulmonary artery. Concentrations of human growth factors and pig cytokines were measured in lung biopsies and perfusate. Intravascular administration of 50 × 106 MSCs was associated with significant and sustained retention of MSCs in lung parenchyma, whereas intrabronchial administration was not. Intravascular administration of 150 × 106 MSCs was the optimal tolerated dose and was associated with increased concentrations of human vascular endothelial growth factor (VEGF) in lung biopsies and decreased concentrations of pig interleukin-8 (IL-8) in the perfusate during 12 hours of EVLP. Intravascular delivery of 150 × 106 MSCs showed preferred outcome compared with intrabronchial delivery to damaged lungs perfused ex vivo. The method was well tolerated and associated with an increased concentration of human VEGF in the lung tissue and a decreased concentration of pig IL-8 in the perfusate.

Heterogeneity of swine lung macrophages inoculated by porcine reproductive and respiratory syndrome virus

ABSTRACTThe biological features of porcine alveolar macrophages (PAMs) and interstitial macrophages (IMs) were investigated, including morphology, nitric oxide (NO) secretion, cell viability and porcine reproductive and respiratory syndrome virus (PRRSV) mRNA expression post-inoculation with TJ-F10 or TJM-F92. Viability and NO secretion of PAMs and IMs were examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and Griess's assay, respectively. mRNA expression of PRRSV, inducible nitric oxide synthase (iNOS) and Arginase1 (Arg1) in PAMs and IMs were detected by quantitative real-time polymerase chain reaction technique. Our results show that PAMs were bigger and more granular than IMs and the Arg1/iNOS value was much higher in PAMs than in IMs. In addition, the vaccine strain TJM-F92 evoked higher NO production in PAMs and IMs compared with the wild type strain TJ-F10. In conclusion, our results indicate that the PAMs and IMs are heterogeneous in morphology, NO production and susceptibility to PRRSV.

A High-Resolution Imaging Technique using a Whole-body, Research Photon Counting Detector CT System.

A high-resolution (HR) data collection mode has been introduced to the whole-body, research photon-counting-detector CT system installed in our laboratory. In this mode, 64 rows of 0.45 mm × 0.45 mm detectors pixels were used, which corresponded to a pixel size of 0.225 mm × 0.225 mm at the iso-center. Spatial resolution of this HR mode was quantified by measuring the MTF from a scan of a 50 micron wire phantom. An anthropomorphic lung phantom, cadaveric swine lung, temporal bone and heart specimens were scanned using the HR mode, and image quality was subjectively assessed by two experienced radiologists. Comparison of the HR mode images against their energy integrating system (EID) equivalents using comb filters was also performed. High spatial resolution of the HR mode was evidenced by the MTF measurement, with 15 lp/cm and 20 lp/cm at 10% and 2% MTF. Images from anthropomorphic phantom and cadaveric specimens showed clear delineation of small structures, such as lung vessels, lung nodules, temporal bone structures, and coronary arteries. Temporal bone images showed critical anatomy (i.e. stapes superstructure) that was clearly visible in the PCD system but hardly visible with the EID system. These results demonstrated the potential application of this imaging mode in lung, temporal bone, and vascular imaging. Other clinical applications that require high spatial resolution, such as musculoskeletal imaging, may also benefit from this high resolution mode.

Treatment with Donor-Specific Alloantigen and Antilymphocyte Mab Three Days after Lung Transplantation Differentially Affects Putative Effector and Regulatory T Cell Populations

Background: Previously, we induced long-term tolerance in a miniature swine lung transplantation model with perioperative whole body irradiation and donor-specific alloantigen infusion. We also showed previously that tolerant animals developed higher frequencies of CD4+CD25high cells in peripheral blood. However, avoiding irradiation and/or pre- or postponing induction remains desirable for clinical applicability. Here we wished to substitute irradiation with anti-lymphocyte antibody treatment before or after transplantation and follow peripheral T cell phenotypes.

The replication of Bangladeshi H9N2 avian influenza viruses carrying genes from H7N3 in mammals

H9N2 avian influenza viruses are continuously monitored by the World Health Organization because they are endemic; they continually reassort with H5N1, H7N9 and H10N8 viruses; and they periodically cause human infections. We characterized H9N2 influenza viruses carrying internal genes from highly pathogenic H7N3 viruses, which were isolated from chickens or quail from live-bird markets in Bangladesh between 2010 and 2013. All of the H9N2 viruses used in this study carried mammalian host-specific mutations. We studied their replication kinetics in normal human bronchoepithelial cells and swine tracheal and lung explants, which exhibit many features of the mammalian airway epithelium and serve as a mammalian host model. All H9N2 viruses replicated to moderate-to-high titers in the normal human bronchoepithelial cells and swine lung explants, but replication was limited in the swine tracheal explants. In Balb/c mice, the H9N2 viruses were nonlethal, replicated to moderately high titers and the infection was confined to the lungs. In the ferret model of human influenza infection and transmission, H9N2 viruses possessing the Q226L substitution in hemagglutinin replicated well without clinical signs and spread via direct contact but not by aerosol. None of the H9N2 viruses tested were resistant to the neuraminidase inhibitors. Our study shows that the Bangladeshi H9N2 viruses have the potential to infect humans and highlights the importance of monitoring and characterizing this influenza subtype to better understand the potential risk these viruses pose to humans.Emerging Microbes and Infections (2016) 5, e35; doi:10.1038/emi.2016.29; published online 20 April 2016

Transmission dynamics of pandemic influenza A(H1N1)pdm09 virus in humans and swine in backyard farms in Tumbes, Peru.

We aimed to determine the frequency of pH1N1 transmission between humans and swine on backyard farms in Tumbes, Peru. Two-year serial cross-sectional study comprising four sampling periods: March 2009 (pre-pandemic), October 2009 (peak of the pandemic in Peru), April 2010 (1st post-pandemic period), and October 2011 (2nd post-pandemic period). Backyard swine serum, tracheal swabs, and lung sample were collected during each sampling period. We assessed current and past pH1N1 infection in swine through serological testing, virus culture, and RT-PCR and compared the results with human incidence data from a population-based active surveillance cohort study in Peru. Among 1303 swine sampled, the antibody prevalence to pH1N1 was 0% pre-pandemic, 8% at the peak of the human pandemic (October 2009), and 24% in April 2010 and 1% in October 2011 (post-pandemic sampling periods). Trends in swine seropositivity paralleled those seen in humans in Tumbes. The pH1N1 virus was isolated from three pigs during the peak of the pandemic. Phylogenetic analysis revealed that these viruses likely represent two separate human-to-swine transmission events in backyard farm settings. Our findings suggest that human-to-swine pH1N1 transmission occurred during the pandemic among backyard farms in Peru, emphasizing the importance of interspecies transmission in backyard pig populations. Continued surveillance for influenza viruses in backyard farms is warranted.

Immunogenic properties and mycoplasmal pneumonia of swine (MPS) lung lesions in Large White pigs selected for higher peripheral blood immune capacity.

Immunogenic properties and mycoplasmal pneumonia of swine (MPS) lung lesions were compared between the immunity-selected Large White line and the non-selected Large White line. The selected Large White line showed a higher level of pulmonary MPS lesions compared with the non-selected Large White line. Subsequent to vaccination, the percentage of natural killer cells and T cells (CD3(+) CD4(+) CD8(-) and CD3(+) CD4(-) CD8(+) T cells) were significantly increased in the non-selected line but remained unchanged in the immunity-selected Large White line. Secretion of Mycoplasma hyopneumoniae vaccine-specific immunoblogulin G and phagocyte activity in peripheral blood were significantly higher in the immunity-selected Large White line than in the non-selected line. Expression of interleukin (IL)-4 and IL-6 messenger RNA in hilar lymph nodes was significantly lower in the immunity-selected Large White line than in the non-selected line. However, expression of IL-10 in all immune tissues was significantly higher in the immunity-selected Large White line. These results suggest that the selection for high immunity was not effective in increasing resistance to MPS lung lesions.

Molecular characterization of Pasteurella multocida isolates from swine lungs by Randomly Amplified Polymorphic DNA

ABSTRACT: Swine respiratory diseases such as atrophic rhinitis and bronchopneumonia caused by Pasteurella (P.) multocida cause important economic losses to the modern swine industry. The purpose of this study was to characterize P. multocida strains isolated from swine lungs by RAPD (Randomly Amplified Polymorphic DNA) to demonstrate their genetic diversity. Ninety-four samples of fragments from lungs with pneumonia and sixty one samples without pneumonia were collected in slaughterhouses in Mato Grosso during the period from December 2009 to March 2010. Clinical cases in 2012 and 2013 were also included in this study. Among the lung fragments with macroscopic lesions, without macroscopic lesions and clinical samples, 40.42%, 4.49% and 100% were positive for P. multocida, respectively. Bacterial identification culturing was confirmed by PCR (polymerase chain reaction) by means of the amplification of the gene kmt1. RAPD technique was performed for 46 isolates, and in every isolate, a total of 7 to 11 amplification bands were detected, composed of 8 clusters based on genetic similarity. Thus, treatment, control and preventive measures should consider the genetic diversity of P. multocida populations in swine herds in order to improve the development of new protocols to produce antimicrobials and vaccines.

Dry Lung as a Physical Model in Studies of Aerosol Deposition.

A new physical model was developed to evaluate the deposition of micro- and nanoaerosol particles (NAPs) into the lungs as a function of size and charges. The model was manufactured of a dry, inflated swine lung produced by Nasco company (Fort Atkinson, WI). The dry lung was cut into two lobes and a conductive tube was glued into the bronchial tube. The upper 1-2-mm-thick layer of the lung lobe was removed with a razor blade to expose the alveoli. The lobe was further enclosed into a plastic bag and placed within a metalized plastic box. The probability of aerosol deposition was calculated by comparing the size distribution of NAPs passed through the lung with that of control, where aerosol passed through a box bypassing the lung. Using this new lung model, it was demonstrated that charged NAPs are deposited inside the lung substantially more efficiently than neutral ones. It was also demonstrated that deposition of neutral NAPs well fits prediction of the Multiple-Path Particle Dosimetry (MPPD) model developed by the Applied Research Associates, Inc. (ARA).

Immunogenic properties of Landrace pigs selected for resistance to mycoplasma pneumonia of swine.

Mycoplasma pneumonia of swine (MPS) lung lesions and immunogenic properties were compared between a Landrace line that was genetically selected for reduced incidence of pulmonary MPS lesions, and a non‐selected Landrace line. The MPS‐selected Landrace line showed significantly lower degrees of pulmonary MPS lesions compared with the non‐selected Landrace line. When changes in immunity before and after vaccination were compared, the percentage of B cells in the peripheral blood of the MPS‐selected Landrace line was significantly lower than that of the non‐selected line. Furthermore, the concentration of growth hormone and the mitogen activity of peripheral blood mononuclear cells in the MPS‐selected Landrace line showed significantly (P < 0.05) lower increases after vaccination than the non‐selected line. Conversely, the concentration of peripheral blood interferon (IFN)‐γ and salivary immunoglobulin A (IgA) after Mycoplasma hyopneumoniae vaccination was significantly higher in the MPS‐selected Landrace line than in the non‐selected line. Gene expression of toll‐like receptor (TLR)2 and TLR4 was significantly higher in the MPS‐selected Landrace line in immune tissues, with the exception of the hilar lymph nodes. The present results suggest that peripheral blood IFN‐γ, salivary IgA TLR2, and TLR4 are important immunological factors influencing the development of MPS lesions.

In Vitro Lung Model Assessing the Efficacy of Surgical Sealants in Treating Alveolar Air Leaks

ABSTRACTPurpose: The lack of reliable testing methods limits the evidence-based practice of surgical sealants in treating alveolar air leak (AAL). We developed an in vitro lung model to evaluate sealants’ efficacy and tested the widely used human thrombin-fibrinogen sponge, TachoSil as an example. Materials and Methods: The caudal lobe of freshly excised swine lung (n = 10) was intubated and ventilated. A focal superficial parenchymal defect (40 × 25 mm) was created in the inflated lung. AAL was assessed with increasing inspired tidal volume (TVi). After sealant application, AAL was assessed in the same way until burst failure, defined as an AAL exceeding 20 mL. To evaluate the elasticity of the sealant, the length of defect was recorded in the inflated lung. Results: Superficial parenchymal defects resulted in AAL increasing with ascending TVi. Multiple linear regression analysis revealed strong correlation between AAL and maximal inspiratory pressure, compliance and resistance. At TVi = 400, 500, and 600 mL, TachoSil achieved sealing in ten, eight, and seven tests, respectively. As TVi increased, superficial defects were still sealed in four, two, and two tests at TVi = 700, 800, and 900 mL, respectively. The burst pressure was 42 ± 5 cmH2O. Adhesive failures were found at the burst pressure in all tests. Concerning elasticity, TachoSil allowed an expansion of the covered lung defect of 7 ± 6 mm. Conclusions: TachoSil demonstrated a strong sealing efficiency and marked elasticity in treating AAL. These results are consistent to that of the previously published animal experiment, suggesting the reliability of the presented in vitro model.

Detection of agents associated with respiratory diseases of swine by real time PCR

Porcine Respiratory Disease Complex (PRDC) is a group of diseases that cause high losses in the swine industry. Several infectious agents are related to PRDC including porcine circovirus 2 (PCV-2), pseudorabies virus (SuHV-1),Haemophilus parasuis (HP), Mycoplasma hypneumoniae (MH) and Pasteurela multocida (PM). The aim of this study was to develop real-time PCRs (qPCR) for the detection of these infectious agents. Oligonucleotides were designed for each specific infectious agent and labeled with different fluorophores to amplify specific parts of the genome. This was done in two groups of reactions—a duplex qPCR for SuHV-1 and PCV-2 and a multiplex qPCR to detect the three bacteria simultaneously. The reactions were tested in 142 pooled samples of swine lymph nodes and lungs with clinical signs of PRDC. There were 135 samples that tested positive for PCV-2, 61 for HP, 29 for PM, 30 for MH and zero for SuHV-1. We recorded 76 cases of co-infection. The qPCRs developed in this study are useful tools in the diagnosis of PRDC.

MO‐AB‐BRA‐09: Temporally Realistic Manipulation a 4D Biomechanical Lung Phantom for Evaluation of Simultaneous Registration and Segmentation

Purpose:To produce multi‐modality compatible, realistic datasets for the joint evaluation of segmentation and registration with a reliable ground truth using a 4D biomechanical lung phantom. The further development of a computer controlled air flow system for recreation of real patient breathing patterns is incorporated for additional evaluation of motion prediction algorithms.Methods:A pair of preserved porcine lungs was pneumatically manipulated using an in‐house computer controlled respirator. The respirator consisted of a set of bellows actuated by a 186 W computer controlled industrial motor. Patient breathing traces were recorded using a respiratory bellows belt during CT simulation and input into a control program incorporating a proportional‐integral‐derivative (PID) feedback controller in LabVIEW. Mock tumors were created using dual compartment vacuum sealed sea sponges. 65% iohexol,a gadolinium‐based contrast agent and 18F‐FDG were used to produce contrast and thus determine a segmentation ground truth. The intensity distributions of the compartments were then digitally matched for the final dataset. A bifurcation tracking pipeline provided a registration ground truth using the bronchi of the lung. The lungs were scanned using a GE Discovery‐ST PET/CT scanner and a Phillips Panorama 0.23T MRI using a T1 weighted 3D fast field echo (FFE) protocol.Results:The standard deviation of the error between the patient breathing trace and the encoder feedback from the respirator was found to be ±4.2%. Bifurcation tracking error using CT (0.97×0.97×3.27 mm3 resolution) was found to be sub‐voxel up to 7.8 cm displacement for human lungs and less than 1.32 voxel widths in any axis up to 2.3 cm for the porcine lungs.Conclusion:An MRI/PET/CT compatible anatomically and temporally realistic swine lung phantom was developed for the evaluation of simultaneous registration and segmentation algorithms. With the addition of custom software and mock tumors, the entire package offers ground truths for benchmarking performance with high fidelity.

Investigation of Pathogenesis of H1N1 Influenza Virus and Swine Streptococcus suis Serotype 2 Co-Infection in Pigs by Microarray Analysis

Swine influenza virus and Streptococcus suis are two important contributors to the porcine respiratory disease complex, and both have significant economic impacts. Clinically, influenza virus and Streptococcus suis co-infections in pigs are very common, which often contribute to severe pneumonia and can increase the mortality. However, the co-infection pathogenesis in pigs is unclear. In the present study, co-infection experiments were performed using swine H1N1 influenza virus and Streptococcus suis serotype 2 (SS2). The H1N1-SS2 co-infected pigs exhibited more severe clinical symptoms, serious pathological changes, and robust apoptosis of lungs at 6 days post-infection compared with separate H1N1 and SS2 infections. A comprehensive gene expression profiling using a microarray approach was performed to investigate the global host responses of swine lungs against the swine H1N1 infection, SS2 infection, co-infection, and phosphate-buffered saline control. Results showed 457, 411, and 844 differentially expressed genes in the H1N1, SS2, and H1N1-SS2 groups, respectively, compared with the control. Noticeably, genes associated with the immune, inflammatory, and apoptosis responses were highly overexpressed in the co-infected group. Pathway analysis indicated that the cytokine–cytokine receptor interactions, MAPK, toll-like receptor, complement and coagulation cascades, antigen processing and presentation, and apoptosis pathway were significantly regulated in the co-infected group. However, the genes related to these were less regulated in the separate H1N1 and SS2 infection groups. This observation suggested that a certain level of synergy was induced by H1N1 and SS2 co-infection with significantly stronger inflammatory and apoptosis responses, which may lead to more serious respiratory disease syndrome and pulmonary pathological lesion.

A rapid and sensitive loop-mediated isothermal amplification procedure (LAMP) for Mycoplasma hyopneumoniae detection based on the p36 gene.

The aim of this study was to establish a method for sensitive and rapid diagnosis of Mycoplasma hyopneumoniae in clinical specimens. To this effect, we employed three sets of primers specifically designed for amplification of nucleic acids under isothermal conditions. After optimization of reaction conditions, M. hyopneumoniae could be successfully detected at 63°C in 45 min through use of the loop-mediated isothermal amplification (LAMP) assay. A positive reaction was identified visually as white precipitate and confirmed by gel electrophoresis. The detection limit for this assay was 10 copies/μL, as observed by electrophoretic analysis. The accuracy of the LAMP reaction was confirmed by restriction endonuclease digestion as well as by direct sequencing of the amplified product. This method can specifically detect M. hyopneumoniae; other species with high homology and other bacterial and virus strains gave negative results. To test the utility of this procedure, the LAMP assay was applied to 40 clinical samples collected from swine lung tissues experimentally challenged with M. hyopneumoniae isolates, and compared to the results from a real-time polymerase chain reaction (PCR) assay. A concordance of 100% was observed between the two assays. In conclusion, the results from our study demonstrated that the LAMP assay provided a rapid reaction and was inexpensive to perform, with no need of complex instruments or systems such as Geneamp PCR. The LAMP assay may therefore be applied in routine diagnosis in the clinical laboratory and for in-field detection of M. hyopneumoniae infection.

Poster - Thur Eve - 71: A 4D Multimodal Lung Phantom for Regmentation Evaluation

Segmentation and registration of medical imaging data are two processes that can be integrated (a process termed regmentation) to iteratively reinforce each other, potentially improving efficiency and overall accuracy. A significant challenge is presented when attempting to validate the joint process particularly with regards to minimizing geometric uncertainties associated with the ground truth while maintaining anatomical realism. This work demonstrates a 4D MRI, PET, and CT compatible tissue phantom with a known ground truth for evaluating registration and segmentation accuracy. The phantom consists of a preserved swine lung connected to an air pump via a PVC tube for inflation. Mock tumors were constructed from sea sponges contained within two vacuum-sealed compartments with catheters running into each one for injection of radiotracer solution. The phantom was scanned using a GE Discovery-ST PET/CT scanner and a 0.23T Phillips MRI, and resulted in anatomically realistic images. A bifurcation tracking algorithm was implemented to provide a ground truth for evaluating registration accuracy. This algorithm was validated using known deformations of up to 7.8 cm using a separate CT scan of a human thorax. Using the known deformation vectors to compare against, 76 bifurcation points were selected. The tracking accuracy was found to have maximum mean errors of −0.94, 0.79 and −0.57 voxels in the left-right, anterior-posterior and inferior-superior directions, respectively. A pneumatic control system is under development to match the respiratory profile of the lungs to a breathing trace from an individual patient.

In vitro antimicrobial susceptibility of Mycoplasma hyorhinis field isolates collected from swine lung specimens in Korea

Mycoplasma hyorhinis is a very common inhabitant of the respiratory tract of pigs with or without pneumonia. Because there is no vaccine available to control M hyorhinis, chemotherapy is the most practical way to treat disease associated with M hyorhinis infection. Therefore, we tested the antimicrobial susceptibility of M hyorhinis isolates recovered from lung specimens of pigs using the liquid minimum inhibitory concentration (MIC) method in tests with 12 antimicrobial agents. The MIC50, MIC90, and range of MICs against 10 field isolates from Korea and the reference strain (ATCC 17981) were investigated. Mycoplasma hyorhinis field isolates were sensitive to lincomycin and tylosin but resistant to erythromycin, spectinomycin, and streptomycin. The MIC90s for lincomycin and tylosin were 0.5 µg per mL and 1.0 µg per mL, respectively. The MIC90s for amoxicillin, erythromycin, penicillin, spectinomycin, and streptomycin were ≥ 64 µg per mL. The MIC90s for gentamicin, kanamycin, and neomycin were 4.0 µg per mL, 8.0 µg per mL and 16 µg per mL, respectively. For oxytetracycline and tetracycline, the MIC50 was 4.0 µg per mL and the MIC90 was 16 µg per mL. These results provide practical information for treatment of M hyorhinis infection in pigs.

TU‐A‐12A‐11: Improved Airway Measurement Accuracy for Low Dose Quantitative CT (qCT) Using Statistical (ASIR), at Reduced DFOV, and High Resolution Kernels in a Phantom and Swine Model

Purpose:To improve the accuracy of airway measures and reduce x‐ray dose in quantitative CT (qCT) of the lung.Methods:qCT was performed on an airway phantom (COPD gene) and a swine model. The airway phantom was used to identify expected improvements in spatial resolution and noise tradeoffs for choice of CT reconstruction kernel and display FOV (DFOV).Results in the phantom were then applied to the swine model. Images were obtained via helical scans that were performed using a GE Discovery CT750 HD with the COPD Gene/SARP protocols except tube current was varied from 790 to 50 mA, and lung inflation was fixed via mechanical ventilator. CT data were reconstructed using STANDARD (Std) and Bone reconstruction kernels for FBP and 100% ASIR at half and full DFOV. Inner Diameter(ID) and wall area percent (WA%) of selected airway sizes were matched across the swine lung and phantom and performed using Airway Inspector (Surgical Planning Laboratory, Brigham and Women's Hospital, Boston, MA). For the swine lung the CT acquisition at 790 mA with ASIR and Bone kernel at half DFOV parameters was the reference standard for comparison to the lower dose scans. Results:The accuracy of the ID and WA% improved by ∼24% and ∼23% for half DFOV with the Bone kernel and ASIR reconstruction for both phantom and swine models for all airways investigated. For low dose qCT, the difference between the reference standard measures and the measures obtained with half DFOV with Bone+ASIR remained much lower than those using current clinical parameters (FBP at full DFOV) even at one fourth the dose for all airways investigated as is shown in Table 1.Conclusion:The combination of ASIR with higher spatial resolution reconstruction shows promise to reduce x‐ray dose and improve qCT of lung airways.NIBIB PB EB 1010 159 JKS Recovery Quantitative Imaging Biomarker Alliance (QIBA) U10 HL109168 SARP

TU‐F‐17A‐03: A 4D Lung Phantom for Coupled Registration/Segmentation Evaluation

Purpose:Coupling the processes of segmentation and registration (regmentation) is a recent development that allows improved efficiency and accuracy for both steps and may improve the clinical feasibility of online adaptive radiotherapy. Presented is a multimodality animal tissue model designed specifically to provide a ground truth to simultaneously evaluate segmentation and registration errors during respiratory motion.Methods:Tumor surrogates were constructed from vacuum sealed hydrated natural sea sponges with catheters used for the injection of PET radiotracer. These contained two compartments allowing for two concentrations of radiotracer mimicking both tumor and background signals. The lungs were inflated to different volumes using an air pump and flow valve and scanned using PET/CT and MRI. Anatomical landmarks were used to evaluate the registration accuracy using an automated bifurcation tracking pipeline for reproducibility. The bifurcation tracking accuracy was assessed using virtual deformations of 2.6 cm, 5.2 cm and 7.8 cm of a CT scan of a corresponding human thorax. Bifurcations were detected in the deformed dataset and compared to known deformation coordinates for 76 points.Results:The bifurcation tracking accuracy was found to have a mean error of −0.94, 0.79 and −0.57 voxels in the left‐right, anterior‐posterior and inferior‐superior axes using a 1×1×5 mm3 resolution after the CT volume was deformed 7.8 cm. The tumor surrogates provided a segmentation ground truth after being registered to the phantom image.Conclusion:A swine lung model in conjunction with vacuum sealed sponges and a bifurcation tracking algorithm is presented that is MRI, PET and CT compatible and anatomically and kinetically realistic. Corresponding software for tracking anatomical landmarks within the phantom shows sub‐voxel accuracy. Vacuum sealed sponges provide realistic tumor surrogate with a known boundary. A ground truth with minimal uncertainty is thus realized that can be used for comparing the performance of registration and segmentation algorithms.

Swine influenza virus strains that induce interferon β in SJPL cells but are insensitive to exogenous recombinant swine interferon β

Background: Viral infections induce expression of type I interferons (IFNα/β) which result in an antiviral state within cells or animals. However, some viruses, notably influenza viruses (IV), have evolved mechanisms of evasion and blocking of IFN to survive in nature. Swine influenza virus (SIV) can inhibit IFN and as with other IV does it through its NS1 protein, identified as a virulence factor in pigs. Methods: To determine whether different SIV strains varied in their ability to induce IFNβ in cell culture and the relative sensitivity of these strains to exogenous IFNβ, three strains were tested in SJPL cells originally deposited as epithelial-like cell line of swine lung origin (ATCC, Richmond, MD) but later characterized as cells of monkey origin. Results: The SIV strains tested here induced significant synthesis of IFNβ in SJPL cells, with levels that were higher to those induced by poly I:C. The induction of IFNβ by SIV peaked at three days post-infection and was not dependent on the infectious virus dose. Interestingly, priming the cells with exogenous recombinant swine IFNβ had no significant inhibitory effect on the replication of these SIV strains. NS1antagonistic compounds did not change IFNβ induction and had variable and unexpected effects on virus replication of the three SIV strains tested. Conclusions: Our study showed that while the SIV strains tested here were capable to induce IFNβ in SJPL cells these were relatively resistant to the antiviral effects of exogenous IFNβ. NS1-antagonistic compounds did not affect IFNβ induction and had variable effects on the replication of the SIV strains tested. These seemingly contradicting results suggest virus evasion by mechanisms other than NS1.