186 results on '"Andrew J Mitchell"'
Search Results
2. The impact of learning‐curve‐experience on transcatheter aortic valve replacement outcomes: Insights from the United Kingdom and Ireland all‐comers second‐generation <scp>ACURATE neo™</scp> transcatheter aortic heart valve registry
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Mark S. Spence, Kamran Baig, Ashan Gunarathne, A. Faour, Ivan P. Casserly, Andrew J Mitchell, Sanjay S Bhandari, Michael S. Cunnington, Kristoffer V. Tanseco, David Hildick-Smith, Richard W Varcoe, Joon Tan, Xavier Armario, Colum G. Owens, Darren Mylotte, and Jan Kovac
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medicine.medical_specialty ,Transcatheter aortic ,medicine.medical_treatment ,Prosthesis Design ,Transcatheter Aortic Valve Replacement ,Valve replacement ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Registries ,Heart valve ,Stroke ,Survival rate ,Aged, 80 and over ,business.industry ,Incidence (epidemiology) ,Mortality rate ,Aortic Valve Stenosis ,General Medicine ,medicine.disease ,United Kingdom ,Surgery ,Treatment Outcome ,medicine.anatomical_structure ,Aortic Valve ,Heart Valve Prosthesis ,Cohort ,Cardiology and Cardiovascular Medicine ,business ,Ireland - Abstract
Background The ACURATE neo™ is a novel, second-generation self-expanding supra-annular transcatheter heart valve (THV). The objective of this multi-centre registry is to assess the safety, clinical utility, and impact of 'learning-curve-experience' (LCE) on transcatheter aortic valve replacement outcomes in the United Kingdom (UK) and Ireland. Methods We prospectively collected data from seven ACURATE neo™ THV implanting centres (n = 484) between February 2016 and November 2020. We compared mortality rates and outcomes in the LCE group (n = 120) compared to next successive 120 cases. Results The mean age of the cohort was 81.9(SD: 6.1) years and the majority were in the moderate risk category (EuroSCORE-II):3.3(SD: 3). The 97.5% of cases were performed under local anesthetic. The valve was successfully deployed in 98.8% of cases. The survival rate at 30 days was 97.9%. The incidence of stroke was 2.5%. Life threatening bleeding occurred in 0.6% of cases and vascular access complications occurred in 21 (4.3%) patients. Implantation-related conduction abnormalities occurred in 8.3% but only 5.6% required a PPM. The successful valve deployment occurred in 96% of the patients in the LCE group compared to 100% in the other group (p = 0.04; OR-2[CI 1.7-2.3]). The mortality rates at 30 days (1.7% vs. 1.7%) and 1 year (1.9% vs. 2.7%) were comparable between the two groups. Conclusions This study represents the largest published UK and Ireland real-world experience of the ACURATE neo™ valve. The procedural success rates and safety outcomes were excellent and endorse its utility in clinical practice. The LCE appears to have an impact on the successful valve deployment but without translating into short-term or long-term outcomes.
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- 2021
3. Bio-nano Science: Better Metrics Would Accelerate Progress
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Matthew Faria, Stuart T. Johnston, Frank Caruso, Andrew J. Mitchell, and Edmund J. Crampin
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Complex data type ,0303 health sciences ,Chemistry ,General Chemical Engineering ,Nanotechnology ,General Chemistry ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Nanomaterials ,03 medical and health sciences ,Nano ,Materials Chemistry ,Biological fluids ,030304 developmental biology - Abstract
An early step of evaluating a nanomaterial’s potential for biological applications is investigating its interactions with cells and biological fluids. These experiments generate complex data, which...
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- 2021
4. Planned withdrawal of dexamethasone after pomalidomide low-dose dexamethasone induction for lenalidomide-refractory multiple myeloma (ALLG MM14)
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Kerry Taylor, Malarmathy Ramachandran, Anna Kalff, Hang Quach, Andrew J. Mitchell, James D'Rozario, Jane Estell, Tiffany Khong, Samuel E Norton, John V. Reynolds, Andrew Spencer, P. Joy Ho, Roslyn A. Kemp, Peter Mollee, and Nola Kennedy
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Oncology ,medicine.medical_specialty ,business.industry ,Low dose ,Refractory Multiple Myeloma ,Hematology ,Pomalidomide ,Dexamethasone ,Thalidomide ,Internal medicine ,Antineoplastic Combined Chemotherapy Protocols ,medicine ,Humans ,business ,Letters to the Editor ,Multiple Myeloma ,Lenalidomide ,medicine.drug - Published
- 2021
5. Emergence of a proton exchange-based isomerization and lactonization mechanism in the plant coumarin synthase COSY
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Colin Y. Kim, Andrew J. Mitchell, David W. Kastner, Claire E. Albright, Michael A. Gutierrez, Christopher M. Glinkerman, Heather J. Kulik, and Jing-Ke Weng
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Multidisciplinary ,General Physics and Astronomy ,General Chemistry ,General Biochemistry, Genetics and Molecular Biology - Abstract
Plants contain rapidly evolving specialized metabolic enzymes to support the synthesis of a myriad of functionally diverse natural products. In the case of coumarin biosynthesis, a BAHD acyltransferase-family enzyme COSY was recently discovered in Arabidopsis that catalyzes coumarin formation fromo-hydroxylatedtrans-hydroxycinnamoyl-CoA substrates. COSY is the first and only BAHD enzyme known to date that catalyzes an intramolecular acyl transfer reaction. Here we combine structural, biochemical, and computational approaches to investigate the mechanistic basis for the unique coumarin synthase activity of COSY. Comparative analyses of crystal structures ofArabidopsis thalianaCOSY relative to other BAHD proteins reveal that COSY possesses an unconventional active-site configuration adapted to its specialized activity. Through deuterium exchange experiments, we discover a unique proton exchange mechanism at the α-carbon of theo-hydroxylatedtrans-hydroxycinnamoyl-CoA substrates during the catalytic cycle of COSY. Mutagenesis studies and quantum mechanical cluster modeling further support that this mechanism is key to COSY’s ability to lower the activation energy of thetrans-to-cisisomerization of the hydroxycinnamoyl-CoA substrates, a critical rate-limiting step leading to coumarin production. This study unveils the emergence of an unconventional catalytic mechanism mediated by a BAHD-family enzyme, and sheds light on the potential evolutionary origin of COSY and its recruitment to the evolutionarily new coumarin biosynthetic pathway in eudicots.
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- 2022
6. Protein precoating modulates biomolecular coronas and nanocapsule-immune cell interactions in human blood
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Shiyao Li, Yi Ju, Jiajing Zhou, Matthew Faria, Ching-Seng Ang, Andrew J. Mitchell, Qi-Zhi Zhong, Tian Zheng, Stephen J. Kent, and Frank Caruso
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Apolipoproteins ,Nanocapsules ,Biomedical Engineering ,Humans ,Immunoglobulins ,General Materials Science ,Protein Corona ,Serum Albumin, Bovine ,General Chemistry ,General Medicine ,Cell Communication - Abstract
The biomolecular corona that forms on particles upon contact with blood plays a key role in the fate and utility of nanomedicines. Recent studies have shown that precoating nanoparticles with serum proteins can improve the biocompatibility and stealth properties of nanoparticles. However, it is not fully clear how precoating influences biomolecular corona formation and downstream biological responses. Herein, we systematically examine three precoating strategies by coating bovine serum albumin (single protein), fetal bovine serum (FBS, mixed proteins without immunoglobulins), or bovine serum (mixed proteins) on three nanoparticle systems, namely supramolecular template nanoparticles, metal-phenolic network (MPN)-coated template (core-shell) nanoparticles, and MPN nanocapsules (obtained after template removal). The effect of protein precoating on biomolecular corona compositions and particle-immune cell interactions in human blood was characterized. In the absence of a pre-coating, the MPN nanocapsules displayed lower leukocyte association, which correlated to the lower amount (by 2-3 fold) of adsorbed proteins and substantially fewer immunoglobulins (more than 100 times) in the biomolecular corona relative to the template and core-shell nanoparticles. Among the three coating strategies, FBS precoating demonstrated the most significant reduction in leukocyte association (up to 97% of all three nanoparticles). A correlation analysis highlights that immunoglobulins and apolipoproteins may regulate leukocyte recognition. This study demonstrates the impact of different precoating strategies on nanoparticle-immune cell association and the role of immunoglobulins in bio-nano interactions.
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- 2022
7. Early immune pressure initiated by tissue-resident memory T cells sculpts tumor evolution in non-small cell lung cancer
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Clare E. Weeden, Velimir Gayevskiy, Claire Marceaux, Daniel Batey, Tania Tan, Kenta Yokote, Nina Tubau Ribera, Allison Clatch, Susan Christo, Charis E. Teh, Andrew J. Mitchell, Marie Trussart, Lucille Rankin, Andreas Obers, Jackson A. McDonald, Kate D. Sutherland, Varun J. Sharma, Graham Starkey, Rohit D’Costa, Phillip Antippa, Tracy Leong, Daniel Steinfort, Louis Irving, Charles Swanton, Claire L. Gordon, Laura K. Mackay, Terence P. Speed, Daniel H.D. Gray, and Marie-Liesse Asselin-Labat
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Cancer Research ,Oncology - Published
- 2023
8. Structure and Antimicrobial Activity of Rare Lactone Lipids from the Sooty Mold (
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Robert W, Schumacher, Amanda L, Waters, Jiangnan, Peng, Richard A, Schumacher, Ailish, Bateman, Josie, Thiele, Andrew J, Mitchell, Samuel G, Miller, Arthur, Goldberg, Siddharth K, Tripathi, Ameeta K, Agarwal, Yike, Zou, Yeun-Mun, Choo, and Mark T, Hamann
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Lactones ,Antifungal Agents ,Anti-Infective Agents ,Ascomycota ,Molecular Structure ,Cryptococcus neoformans ,Lipids ,Article - Abstract
Two new lactone lipids, scoriosin (1) and its methyl ester (2), with a rare furylidene ring joined to a tetrahydrofurandione ring, were isolated from Scorias spongiosa, commonly referred to as sooty mold. The planar structure of these compounds was assigned by 1D and 2D NMR. The conformational analysis of these molecules was undertaken to evaluate the relative and absolute configuration through GIAO NMR chemical shift analysis and ECD calculation. In addition to the potent antimicrobial activities, compound 2 strongly potentiated the activity of amphotericin B against Cryptococcus neoformans, suggesting the potential utility of this compound in combination therapies for treating cryptococcal infections.
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- 2022
9. CyTOF mass cytometry analysis of human memory CD4
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Lisa J, Ioannidis, Andrew J, Mitchell, Tian, Zheng, and Diana S, Hansen
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CD4-Positive T-Lymphocytes ,Memory B Cells ,T-Lymphocytes ,Humans ,Lymphocyte Count ,Flow Cytometry - Abstract
High-dimensional mass cytometry provides unparalleled insight into the cellular composition of the immune system. Here, we describe a mass-cytometry-based protocol to examine memory CD4
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- 2022
10. Early Immune Pressure Initiated by Tissue-Resident Memory T Cells Sculpts Tumour Evolution in Non-Small Cell Lung Cancer
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Clare E. Weeden, Velimir Gayevskiy, Claire Marceaux, Daniel Batey, Tania Tan, Kenta Yokote, Nina Tubau Ribera, Allison Clatch, Susan Christo, Charis E. Teh, Andrew J. Mitchell, Marie Trussart, Jackson A. McDonald, Kate D. Sutherland, Varun J. Sharma, Graham Starkey, Rohit D'Costa, Phillip Antippa, Tracy Leong, Daniel Steinfort, Louis Irving, Charles Swanton, Claire L. Gordon, Laura K. Mackay, Terry Speed, Daniel HD Gray, and Marie-Liesse Asselin-Labat
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History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
11. Coating flow on a rotating cylinder in the presence of an irrotational airflow with circulation
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Andrew J. Mitchell, Brian R. Duffy, and Stephen K. Wilson
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Mechanics of Materials ,Mechanical Engineering ,TJ ,Condensed Matter Physics - Abstract
A detailed analysis of steady coating flow of a thin film of a viscous fluid on the outside of a uniformly rotating horizontal circular cylinder in the absence of surface-tension effects but in the presence of a non-uniform pressure distribution due to an irrotational airflow with circulation shows that the presence of the airflow can result in qualitatively different behaviour of the fluid film from that in classical coating flow. Full-film solutions corresponding to a continuous film of fluid covering the entire cylinder are possible only when the flux and mass of fluid do not exceed critical values, which are determined in terms of the non-dimensional parameters $F$ and $K$ representing the speed of the far-field airflow and the circulation of the airflow, respectively. The qualitative changes in the behaviour of the film thickness as $F$ and $K$ are varied are described. In particular, the film thickness can have as many as four stationary points and, in general, has neither top-to-bottom nor right-to-left symmetry. In addition, when the circulation of the airflow is in the same direction as the rotation of the cylinder the maximum mass of fluid that can be supported on the cylinder is always less than that in classical coating flow, whereas when the circulation is in the opposite direction the maximum mass of fluid can be greater than that in classical coating flow.
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- 2021
12. Prediction of shoreline–shelf depositional process regime guided by palaeotidal modelling
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Jon Hill, Andrew J. Mitchell, Howard D. Johnson, Peter A. Allison, Daniel S. Collins, Alexandros Avdis, Martin R. Wells, Gary J. Hampson, Christopher Dean, Matthew D. Piggott, and Shell International Exploration & Production Inc.
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geography ,Tidal resonance ,geography.geographical_feature_category ,business.industry ,Continental shelf ,04 Earth Sciences ,Fluvial ,Context (language use) ,Geology ,Sedimentary depositional environment ,General Earth and Planetary Sciences ,business ,Sediment transport ,Tidal power ,Geomorphology ,Beach morphodynamics - Abstract
Ancient shoreline–shelf depositional systems are influenced by an unusually wide array of geological, biological and hydrodynamic processes, with sediment transport and deposition primarily determined by the interaction of river, wave (including storm) and tidal processes, and changes in relative sea level. Understanding the impact of these processes on shoreline–shelf morphodynamics and stratigraphic preservation remains challenging. Numerical modelling integrated with traditional facies analysis provides an increasingly viable approach, with the potential to quantify, and thereby improve understanding of, the impact of these complex coastal sedimentary processes. An integrated approach is presented here that focuses on palaeotidal modelling to investigate the controls on ancient tides and their influence on sedimentary deposition and preservation – one of the three cornerstones of the ternary process classification scheme of shoreline-shelf systems. Numerical tidal modelling methodology is reviewed and illustrated in three palaeotidal model case studies of different scales and focus. The results are synthesised in the context of shoreline–shelf processes, including a critique and modification of the process-based classification scheme. The emphasis on tidal processes reflects their global importance throughout Earth’s history. Ancient palaeotidal models are able to highlight and quantify the following four controls on tidal processes: (1) the physiography (shape and depth) of oceans (1000s km scale) determines the degree of tidal resonance; (2) the physiography of ocean connections to partly enclosed water bodies (100–1000s km scale) determines the regional-scale flux of tidal energy (inflow versus outflow); (3) the physiography of continental shelves influences shelf tidal resonance potential; and (4) tides in relatively local-scale embayments (typically 1–10s km scale) are influenced by the balance of tidal amplification due to funnelling, shoaling and resonance effects versus frictional damping. In deep time, palaeogeographic and palaeobathymetric uncertainty can be accounted for in palaeotidal models by performing sensitivity analyses to different scenarios, across this range of spatial scales. These tidal process controls are incorporated into an updated predictive decision tree for determining shoreline–shelf process regime in terms of the relative interaction of wave, fluvial and tidal processes. The predictive decision tree considers the effects of basin physiography, shelf width and shoreline morphology on wave, fluvial and tidal processes separately. Uncertainty and ambiguity in applying the widely used three-tier process classification scheme are reduced by using the decision tree in conjunction with a proposed two-tier classification of process regime that is limited to primary and secondary processes. This two-tier classification scheme is illustrated in the three case studies, showing how integration of numerical modelling with facies analysis of the preserved stratigraphic record improves confidence in prediction of tide-influenced shoreline-shelf process regimes. Wider application of this approach will further improve process-based classifications and predictions of modern and ancient shoreline–shelf systems.
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- 2021
13. A distinct CD115-erythro-myeloid precursor present at the maternal-embryonic interface and in the bone marrow of adult mice
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Simone Rizzetto, Andrew J. Mitchell, Shweta Tikoo, Maria Elizabeth Torres-Pacheco, Stuart T. Fraser, Brendon Martinez, Renhua Song, Steffen Jung, Wolfgang Weninger, Lisa E. Shaw, Matthias Farlik, Rohit Jain, Fabio Luciani, Justin J.-L. Wong, and Matthias Wielscher
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Haematopoiesis ,Myeloid ,medicine.anatomical_structure ,Monocyte ,medicine ,Macrophage ,Bone marrow ,Yolk sac ,Biology ,Progenitor cell ,Embryonic stem cell ,Cell biology - Abstract
During ontogeny, macrophages develop from CD115+precursors, including erythro-myeloid progenitors (EMP). EMP arise in the embryonic yolk sac, the primary site of early haematopoiesis. In adults, CD115+bone marrow-derived monocytes represent essential macrophage precursors. Herein, we identify a CD115-macrophage precursor within the adult bone marrow that is unrelated to the classical monocyte lineage but rather shares transcriptomic and functional characteristics of embryonic EMP. These EMPROR (forErythroMyeloidPrecursor) cells are capable of efficiently generating macrophages in disease settings. During early development, EMPROR cells were largely absent from the yolk sac but were instead found at the embryonic-maternal interface in the uterine wall. Unexpectedly, the latter site contains robust haematopoietic activity and harbours defined embryonic haematopoietic progenitor cells, including classical CD115+EMP. Our data suggest the existence of an alternative pathway of macrophage generation in the adult. Further, we uncover a hitherto unknown site of earliest blood cell development.
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- 2021
14. Quantitatively Tracking Bio-Nano Interactions of Metal-Phenolic Nanocapsules by Mass Cytometry
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Jiajing Zhou, Frank Caruso, Stephen J. Kent, Andrew J. Mitchell, Christopher J.H. Porter, Shiyao Li, Tian Zheng, Ka Fung Noi, and Yi Ju
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Male ,Biodistribution ,Materials science ,Metal Nanoparticles ,02 engineering and technology ,Polyethylene glycol ,Pyrogallol ,Nanocapsules ,Polyethylene Glycols ,Rats, Sprague-Dawley ,03 medical and health sciences ,chemistry.chemical_compound ,Mice ,In vivo ,Animals ,Humans ,General Materials Science ,Particle Size ,Metal-Organic Frameworks ,030304 developmental biology ,0303 health sciences ,technology, industry, and agriculture ,021001 nanoscience & nanotechnology ,Flow Cytometry ,Blood ,RAW 264.7 Cells ,chemistry ,Colloidal gold ,Drug delivery ,Biophysics ,Gold ,0210 nano-technology ,Ethylene glycol ,Iron oxide nanoparticles - Abstract
Polymer nanocapsules, with a hollow structure, are increasingly finding widespread use as drug delivery carriers; however, quantitatively evaluating the bio-nano interactions of nanocapsules remains challenging. Herein, poly(ethylene glycol) (PEG)-based metal-phenolic network (MPN) nanocapsules of three sizes (50, 100, and 150 nm) are engineered via supramolecular template-assisted assembly and the effect of the nanocapsule size on bio-nano interactions is investigated using in vitro cell experiments, ex vivo whole blood assays, and in vivo rat models. To track the nanocapsules by mass cytometry, a preformed gold nanoparticle (14 nm) is encapsulated into each PEG-MPN nanocapsule. The results reveal that decreasing the size of the PEG-MPN nanocapsules from 150 to 50 nm leads to reduced association (up to 70%) with phagocytic blood cells in human blood and prolongs in vivo systemic exposure in rat models. The findings provide insights into MPN-based nanocapsules and represent a platform for studying bio-nano interactions.
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- 2021
15. CyTOF mass cytometry analysis of human memory CD4+ T cells and memory B cells
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Lisa J. Ioannidis, Andrew J. Mitchell, Tian Zheng, and Diana S. Hansen
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General Immunology and Microbiology ,General Neuroscience ,General Biochemistry, Genetics and Molecular Biology - Published
- 2022
16. Early immune pressure imposed by tissue resident memory T cells sculpts tumour evolution in non-small cell lung cancer
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Clare E Weeden, Velimir Gayevskiy, Marie Trussart, Claire Marceaux, Nina Tubau Ribera, Daniel Batey, Charis E Teh, Andrew J Mitchell, Phillip Antippa, Tracy Leong, Daniel Steinfort, Louis Irving, Claire L Gordon, Charles Swanton, Terence P Speed, Daniel HD Gray, and Marie-Liesse Asselin-Labat
- Abstract
Tissue-resident memory T cells (TRM) provide immune defence against local infection and can inhibit cancer progression. However, it is unclear to what extent chronic inflammation impacts TRMactivation and how the immune pressure exerted by TRMaffects developing tumours in humans. We performed deep profiling of lung cancers arising in never-smokers (NS) and ever-smokers (ES), finding evidence of enhanced TRMimmunosurveillance in ES lung. Only tumours arising in ES patients underwent clonal immune escape, even when evaluating cancers with similar tumour mutational burden to NS patients, suggesting that the timing of immune pressure exerted by TRMis a critical factor in the evolution of tumour immune evasion. Tumours grown in T cell quiescent NS lungs displayed little evidence of immune evasion and had fewer neoantigens with low diversity, paradoxically making them amenable to treatment with agonist of the costimulatory molecule, ICOS. These data demonstrate local environmental insults enhance TRMimmunosurveillance of human tissue, shape the evolution of tumour immunogenicity and that this interplay informs effective immunotherapeutic modalities.
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- 2021
17. Making the most of high-dimensional cytometry data
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Andrew J. Mitchell, Roslyn A. Kemp, Thomas M. Ashhurst, Felix Marsh-Wakefield, Helen M. McGuire, Julia Kh Leman, Samuel E Norton, Jessica E Harte, and Joanna M. Roberts
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0301 basic medicine ,mass cytometry ,experimental design ,medicine.diagnostic_test ,Computer science ,flow cytometry ,Immunology ,Cell Biology ,High dimensional ,Review ,Data science ,Flow cytometry ,Visualization ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Data quality ,high‐dimensional data ,medicine ,Immunology and Allergy ,Humans ,Mass cytometry ,Cytometry ,Analysis ,030215 immunology - Abstract
High‐dimensional cytometry represents an exciting new era of immunology research, enabling the discovery of new cells and prediction of patient responses to therapy. A plethora of analysis and visualization tools and programs are now available for both new and experienced users; however, the transition from low‐ to high‐dimensional cytometry requires a change in the way users think about experimental design and data analysis. Data from high‐dimensional cytometry experiments are often underutilized, because of both the size of the data and the number of possible combinations of markers, as well as to a lack of understanding of the processes required to generate meaningful data. In this article, we explain the concepts behind designing high‐dimensional cytometry experiments and provide considerations for new and experienced users to design and carry out high‐dimensional experiments to maximize quality data collection., High‐dimensional cytometry represents an exciting new era of immunology research; however, the transition from low‐ to high‐dimensional cytometry requires a change in the way users think about experimental design and data analysis. We explain the concepts behind designing high‐dimensional cytometry experiments and provide considerations for new and experienced users to design and carry out high‐dimensional experiments.
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- 2021
18. Perivascular macrophages create an intravascular niche for CD8+ T cell localisation prior to the onset of fatal experimental cerebral malaria
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Andrew J. Mitchell, Jim S. Qin, Saparna Pai, Michael D. Lovelace, Tania F. de Koning-Ward, and Georges Er Grau
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0301 basic medicine ,perivascular macrophage ,Pathology ,medicine.medical_specialty ,Endothelium ,Immunology ,malaria ,Context (language use) ,Biology ,CD8+ T cells ,immune response ,03 medical and health sciences ,0302 clinical medicine ,Immune system ,parasitic diseases ,medicine ,Immunology and Allergy ,Cytotoxic T cell ,Plasmodium berghei ,General Nursing ,Monocyte ,2‐photon intravital microscopy ,RC581-607 ,biology.organism_classification ,030104 developmental biology ,medicine.anatomical_structure ,Immunologic diseases. Allergy ,Intravital microscopy ,CD8 ,030215 immunology - Abstract
Objectives: The immunologic events that build up to the fatal neurological stage of experimental cerebral malaria (ECM) are incompletely understood. Here, we dissect immune cell behaviour occurring in the central nervous system (CNS) when Plasmodium berghei ANKA (PbA)-infected mice show only minor clinical signs. Methods: A 2-photon intravital microscopy (2P-IVM) brain imaging model was used to study the spatiotemporal context of early immunological events in situ during ECM. Results: Early in the disease course, antigen-specific CD8+ T cells came in contact and arrested on the endothelium of post-capillary venules. CD8+ T cells typically adhered adjacent to, or were in the near vicinity of, perivascular macrophages (PVMs) that line post-capillary venules. Closer examination revealed that CD8+ T cells crawled along the inner vessel wall towards PVMs that lay on the abluminal side of large post-capillary venules. 'Activity hotspots' in large post-capillary venules were characterised by T-cell localisation, activated morphology and clustering of PVM, increased abutting of post-capillary venules by PVM and augmented monocyte accumulation. In the later stages of infection, when mice exhibited neurological signs, intravascular CD8+ T cells increased in number and changed their behaviour, actively crawling along the endothelium and displaying frequent, short-term interactions with the inner vessel wall at hotspots. Conclusion: Our study suggests an active interaction between PVM and CD8+ T cells occurs across the blood-brain barrier (BBB) in early ECM, which may be the initiating event in the inflammatory cascade leading to BBB alteration and neuropathology.
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- 2021
19. Unsteady coating flow on a rotating cylinder in the presence of an irrotational airflow with circulation
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Andrew J. Mitchell, Brian R. Duffy, and Stephen K. Wilson
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Fluid Flow and Transfer Processes ,Mechanics of Materials ,Mechanical Engineering ,Computational Mechanics ,QA ,Condensed Matter Physics ,QC - Abstract
Unsteady two-dimensional coating flow of a thin film of a viscous fluid on the outside of a uniformly rotating horizontal circular cylinder in the presence of a steady two-dimensional irrotational airflow with circulation is considered. The analysis of this problem by Newell and Viljoen [Phys. Fluids 31(3), 034106 (2019)], who sought to generalize the work of Hinch and Kelmanson [Proc. R. Soc. London, Ser. A 459(2033), 1193–1213 (2003)] to include the effect of the airflow, is revisited. In contrast with the claim of Newell and Viljoen that the flow is conditionally unstable (in the sense that the solution for the film thickness grows without bound for certain values of the physical parameters), it is shown that, in fact, the film remains unconditionally stable in the presence of the airflow.
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- 2022
20. Perivascular macrophages create an intravascular niche for CD8
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Jim, Qin, Michael D, Lovelace, Andrew J, Mitchell, Tania, de Koning-Ward, Georges Er, Grau, and Saparna, Pai
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perivascular macrophage ,parasitic diseases ,malaria ,Original Article ,2‐photon intravital microscopy ,CD8+ T cells ,immune response - Abstract
Objectives The immunologic events that build up to the fatal neurological stage of experimental cerebral malaria (ECM) are incompletely understood. Here, we dissect immune cell behaviour occurring in the central nervous system (CNS) when Plasmodium berghei ANKA (PbA)‐infected mice show only minor clinical signs. Methods A 2‐photon intravital microscopy (2P‐IVM) brain imaging model was used to study the spatiotemporal context of early immunological events in situ during ECM. Results Early in the disease course, antigen‐specific CD8+ T cells came in contact and arrested on the endothelium of post‐capillary venules. CD8+ T cells typically adhered adjacent to, or were in the near vicinity of, perivascular macrophages (PVMs) that line post‐capillary venules. Closer examination revealed that CD8+ T cells crawled along the inner vessel wall towards PVMs that lay on the abluminal side of large post‐capillary venules. ‘Activity hotspots’ in large post‐capillary venules were characterised by T‐cell localisation, activated morphology and clustering of PVM, increased abutting of post‐capillary venules by PVM and augmented monocyte accumulation. In the later stages of infection, when mice exhibited neurological signs, intravascular CD8+ T cells increased in number and changed their behaviour, actively crawling along the endothelium and displaying frequent, short‐term interactions with the inner vessel wall at hotspots. Conclusion Our study suggests an active interaction between PVM and CD8+ T cells occurs across the blood–brain barrier (BBB) in early ECM, which may be the initiating event in the inflammatory cascade leading to BBB alteration and neuropathology., Our study suggests that perivascular macrophages and CD8+ T cells interact across the blood–brain barrier (BBB) in the early stages of experimental cerebral malaria, which may be the initiating event in the inflammatory cascade leading to BBB alteration and neuropathology.
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- 2020
21. Person-Specific Biomolecular Coronas Modulate Nanoparticle Interactions with Immune Cells in Human Blood
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Yi Ju, Arnold Reynaldi, Zhixing Lin, Timothy E. Schlub, Frank Caruso, Kristofer J. Thurecht, Laura F. Dagley, Jiwei Cui, Stephen J. Kent, Hannah G. Kelly, Andrew I. Webb, Miles P. Davenport, Adam K. Wheatley, Andrew J. Mitchell, Craig A. Bell, and Sukhdeep K Spall
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Proteomics ,General Physics and Astronomy ,Nanoparticle ,Protein Corona ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Immune system ,PEG ratio ,Humans ,General Materials Science ,Particle Size ,biology ,Chemistry ,General Engineering ,Blood Proteins ,021001 nanoscience & nanotechnology ,Silicon Dioxide ,Blood proteins ,0104 chemical sciences ,Complement system ,biology.protein ,Biophysics ,Nanoparticles ,Particle size ,Antibody ,0210 nano-technology - Abstract
When nanoparticles interact with human blood, a multitude of plasma components adsorb onto the surface of the nanoparticles, forming a biomolecular corona. Corona composition is known to be influenced by the chemical composition of nanoparticles. In contrast, the possible effects of variations in the human blood proteome between healthy individuals on the formation of the corona and its subsequent interactions with immune cells in blood are unknown. Herein, we prepared and examined a matrix of 11 particles (including organic and inorganic particles of three sizes and five surface chemistries) and plasma samples from 23 healthy donors to form donor-specific biomolecular coronas (personalized coronas) and investigated the impact of the personalized coronas on particle interactions with immune cells in human blood. Among the particles examined, poly(ethylene glycol) (PEG)-coated mesoporous silica (MS) particles, irrespective of particle size (800, 450, or 100 nm in diameter), displayed the widest range (up to 60-fold difference) of donor-dependent variance in immune cell association. In contrast, PEG particles (after MS core removal) of 860, 518, or 133 nm in diameter displayed consistent stealth behavior (negligible cell association), irrespective of plasma donor. For comparison, clinically relevant PEGylated doxorubicin-encapsulated liposomes (Doxil) (74 nm in diameter) showed significant variance in association with monocytes and B cells across all plasma donors studied. An in-depth proteomic analysis of each biomolecular corona studied was performed, and the results were compared against the nanoparticle-blood cell association results, with individual variance in the proteome driving differential association with specific immune cell types. We identified key immunoglobulin and complement proteins that explicitly enriched or depleted within the corona and which strongly correlated with the cell association pattern observed across the 23 donors. This study demonstrates how plasma variance in healthy individuals significantly influences the blood immune cell interactions of nanoparticles.
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- 2020
22. Prediction of shoreline–shelf depositional process regime guided by palaeotidal modelling
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Daniel Collins, Alexandros Avdis, Martin R. Wells, Andrew J. Mitchell, Peter Allison, Howard Johnson, Gary J. Hampson, Jon Hill, Christopher David Dean, and Matthew Piggott
- Abstract
Ancient shoreline–shelf depositional systems are influenced by an unusually wide array of geological, biological and hydrodynamic processes, with sediment transport and deposition primarily determined by the interaction of river, wave (including storm) and tidal processes, and changes in relative sea level. Understanding the impact of these processes on shoreline–shelf morphodynamics and stratigraphic preservation remains challenging. Numerical modelling integrated with traditional facies analysis provides an increasingly viable approach, with the potential to quantify, and thereby improve understanding of, the impact of these complex coastal sedimentary processes. An integrated approach is presented here that focuses on palaeotidal modelling to investigate the controls on ancient tides and their influence on sedimentary deposition and preservation – one of the three cornerstones of the ternary process classification scheme of shoreline-shelf systems. Numerical tidal modelling methodology is reviewed and illustrated in three palaeotidal model case studies of different scales and focus. The results are synthesised in the context of shoreline–shelf processes, including a critique and modification of the process-based classification scheme.The emphasis on tidal processes reflects their global importance throughout Earth’s history. Ancient palaeotidal models are able to highlight and quantify the following four controls on tidal processes: (1) the physiography (shape and depth) of oceans (1000s km scale) determines the degree of tidal resonance; (2) the physiography of ocean connections to partly enclosed water bodies (100–1000s km scale) determines the regional-scale flux of tidal energy (inflow versus outflow); (3) the physiography of continental shelves influences shelf tidal resonance potential; and (4) tides in relatively local-scale embayments (typically 1–10s km scale) are influenced by the balance of tidal amplification due to funnelling, shoaling and resonance effects versus frictional damping. In deep time, palaeogeographic and palaeobathymetric uncertainty can be accounted for in palaeotidal models by performing sensitivity analyses to different scenarios, across this range of spatial scales.These tidal process controls are incorporated into an updated predictive decision tree for determining shoreline–shelf process regime in terms of the relative interaction of wave, fluvial and tidal processes. The predictive decision tree considers the effects of basin physiography, shelf width and shoreline morphology on wave, fluvial and tidal processes separately. Uncertainty and ambiguity in applying the widely used three-tier process classification scheme are reduced by using the decision tree in conjunction with a proposed two-tier classification of process regime that is limited to primary and secondary processes. This two-tier classification scheme is illustrated in the three case studies, showing how integration of numerical modelling with facies analysis of the preserved stratigraphic record improves confidence in prediction of tide-influenced shoreline-shelf process regimes. Wider application of this approach will further improve process-based classifications and predictions of modern and ancient shoreline–shelf systems.
- Published
- 2020
23. Schopenhauer’s Influence on Wagner
- Author
-
Kevin C. Karnes and Andrew J. Mitchell
- Subjects
Psychoanalysis ,Philosophy ,Opera ,media_common.quotation_subject ,Metaphysics ,Compassion ,Creativity ,media_common - Abstract
This chapter traces the evolution of Wagner’s engagement with Schopenhauer’s philosophy from the 1850s through 1883. It considers Wagner’s three Schopenhauerian operas in relation to the composer’s contemporary writings, suggesting that both music and prose were vehicles through which he sought to extend and correct what he perceived as shortcomings in Schopenhauer’s work. In Tristan und Isolde and related correspondence, Wagner identified a pathway to redemption from suffering born of Schopenhauerian will, attainable through the experience of erotic love. In Die Meistersinger von Nürnberg and the essay “Beethoven,” Wagner elaborated Schopenhauer’s theory of dreams to account for the origins of artistic creativity. In Parsifal and a series of essays appended to “Religion and Art,” Wagner extended Schopenhauer’s notion of compassion to include all living beings, identifying vegetarianism as one of its principal tenets and the Eucharist as its cardinal expression in ritual.
- Published
- 2020
24. A Brief History of Things
- Author
-
Andrew J. Mitchell
- Published
- 2020
25. Engineering of Nebulized Metal–Phenolic Capsules for Controlled Pulmonary Deposition
- Author
-
Yu-Wei Lin, Leslie Y. Yeo, Md. Arifur Rahim, Jiaying Song, Ting Yi Wang, Shuaijun Pan, Christoph E. Hagemeyer, Evelyn Tsantikos, Yizhe Cheng, Nadja Bertleff-Zieschang, Gyeongwon Yun, Frank Caruso, Srinivas Mettu, Jingqu Chen, Andrew J. Mitchell, Christina Cortez-Jugo, Margaret L. Hibbs, and Yi Ju
- Subjects
Materials science ,Biocompatibility ,capsules ,General Chemical Engineering ,pulmonary delivery ,General Physics and Astronomy ,Medicine (miscellaneous) ,Nanoparticle ,02 engineering and technology ,Nanoengineering ,010402 general chemistry ,01 natural sciences ,Biochemistry, Genetics and Molecular Biology (miscellaneous) ,medicine ,Deposition (phase transition) ,General Materials Science ,lcsh:Science ,aerodynamic diameter ,Lung ,Full Paper ,nebulization ,metal–phenolic networks ,General Engineering ,Capsule ,Full Papers ,respiratory system ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,medicine.anatomical_structure ,Drug delivery ,Particle ,lcsh:Q ,0210 nano-technology ,Biomedical engineering - Abstract
Particle‐based pulmonary delivery has great potential for delivering inhalable therapeutics for local or systemic applications. The design of particles with enhanced aerodynamic properties can improve lung distribution and deposition, and hence the efficacy of encapsulated inhaled drugs. This study describes the nanoengineering and nebulization of metal–phenolic capsules as pulmonary carriers of small molecule drugs and macromolecular drugs in lung cell lines, a human lung model, and mice. Tuning the aerodynamic diameter by increasing the capsule shell thickness (from ≈100 to 200 nm in increments of ≈50 nm) through repeated film deposition on a sacrificial template allows precise control of capsule deposition in a human lung model, corresponding to a shift from the alveolar region to the bronchi as aerodynamic diameter increases. The capsules are biocompatible and biodegradable, as assessed following intratracheal administration in mice, showing >85% of the capsules in the lung after 20 h, but 90% of capsules remaining nonassociated with cells. The amenability to nebulization, capacity for loading, tunable aerodynamic properties, high biocompatibility, and biodegradability make these capsules attractive for controlled pulmonary delivery., The aerodynamic diameters of metal–phenolic capsules are nanoengineered by increasing their shell thickness, which facilitates tailored capsule deposition in a mechanical lung model. The engineered capsules are promising for pulmonary delivery owing to their robustness for nebulization, biocompatibility, biodegradability, and their capacity for cargo loading and surface functionalization.
- Published
- 2020
26. Fichte’s Subject and Its Romantic Transformations
- Author
-
Andrew J. Mitchell
- Subjects
German ,Literary theory ,Aesthetics ,Philosophy ,language ,Subject (philosophy) ,Composition (language) ,Romance ,language.human_language ,Order (virtue) ,Key (music) - Abstract
This essay explores Fichte’s influence on German Romantic literary theory and composition in the work of Novalis and Friedrich Schlegel. The key moment in Fichte that gets taken up by Novalis and Schlegel is the idea that the subject must posit itself. For Novalis, such self-positing is always a matter of self-representation, and thus an aesthetic act. Schlegel adds to this by showing that such self-positing is never certain of success, that one can never truly possess oneself fully. Each author begins from a Fichtean position in order to show not its limitations, but its primacy for aesthetic creation.
- Published
- 2020
27. Correction to: Quantitative Measurement of Cell-Nanoparticle Interactions Using Mass Cytometry
- Author
-
Andrew J, Mitchell, Angela, Ivask, and Yi, Ju
- Abstract
This chapter was inadvertently published with the acknowledgement section leaving out the following sentence: "This work received funding from South Australian Government PRIF program Project "International Cluster on Nanosafety" of Nicolas H. Voelcker and Enzo Lombi." This correction has been updated in the chapter.
- Published
- 2019
28. Fist in man implantation of a leadless pacemaker in the left atrial appendage following Mustard repair
- Author
-
Andrew J Mitchell, Kevin Walsh, and Nina Murphy
- Subjects
Appendage ,Pacemaker, Artificial ,medicine.medical_specialty ,Fist ,business.industry ,Mustard Repair ,Surgery ,Arterial Switch Operation ,Left atrial ,Physiology (medical) ,medicine ,Humans ,Atrial Appendage ,Cardiology and Cardiovascular Medicine ,business - Published
- 2021
29. Serpinb9 is a marker of antigen cross-presenting dendritic cells
- Author
-
Jose A Villadangos, Wolfgang Weninger, Alexandra Rizzitelli, L.T. Joeckel, Javier Vega-Ramos, Matthew Mangan, Dion Kaiserman, Phillip I. Bird, Andrew J. Mitchell, and Ben Roediger
- Subjects
0301 basic medicine ,Follicular dendritic cells ,Immunology ,Cross-presentation ,Dendritic cell ,Biology ,SERPINB9 ,Cell biology ,Granzyme B ,03 medical and health sciences ,030104 developmental biology ,Antigen ,Cytotoxic T cell ,Molecular Biology ,CD8 - Abstract
Serpinb9 (Sb9, also called Spi6) is an intracellular inhibitor of granzyme B (grB) that protects cytotoxic lymphocytes from grB-mediated death. In addition, Sb9 is also expressed in accessory immune cells, including dendritic cells (DCs), although its role is debated. Recently, we have demonstrated that Sb9 plays a grB-independent role in cross-presentation of antigens by CD8+ DCs. Here, using a mouse line expressing green fluorescent protein knocked in under the control of the Sb9 promoter, we demonstrate that Sb9 expression is highest in those tissue-resident and migratory DC subsets capable of cross-presentation. Further, we show that CD8+ DCs can be divided into two subsets based on Sb9 expression, and that only the subset expressing higher levels of Sb9 is capable of cross-presentation. These findings add support for role for Sb9 cross-presentation, and indicate that high Sb9 expression is a novel marker of cross-presentation capable DCs.
- Published
- 2017
30. The kynurenine pathway and parasitic infections that affect CNS function
- Author
-
Leia Hee, Georges E. Grau, Loke Tim Khaw, Nicholas H. Hunt, Jintao Guo, Lay Khoon Too, Andrew J. Mitchell, and Helen J. Ball
- Subjects
0301 basic medicine ,Pharmacology ,Kynurenine pathway ,Central nervous system ,Disease ,Biology ,Central Nervous System Parasitic Infections ,medicine.disease ,Toxoplasmosis ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,030104 developmental biology ,medicine.anatomical_structure ,Kynurenic acid ,chemistry ,Immunology ,medicine ,Animals ,Humans ,Indoleamine 2,3-dioxygenase ,Kynurenine ,Metabolic Networks and Pathways ,Quinolinic acid - Abstract
The kynurenine pathway of tryptophan metabolism has been implicated in brain function, immunoregulation, anti-microbial mechanisms and pregnancy. Some of these actions are due to depletion of tryptophan and others to the formation of biologically active metabolites. This review focuses on the roles of the kynurenine pathway in host responses during two parasitic diseases of major health and economic importance, malaria and toxoplasmosis, with an emphasis on their impacts on CNS function. This article is part of the Special Issue entitled ‘The Kynurenine Pathway in Health and Disease’.
- Published
- 2017
31. What Is Called Drinking?: Heidegger, Wine, and Loss
- Author
-
Heidegger Circle and Andrew J. Mitchell
- Subjects
Wine ,Aesthetics ,media_common.quotation_subject ,Art ,media_common - Published
- 2017
32. Brains, bacteria and behaviors: the role of interferon-gamma in the pathogenesis of pneumococcal meningitis
- Author
-
Lay Khoon Too and Andrew J. Mitchell
- Subjects
0301 basic medicine ,Hearing loss ,medicine.drug_class ,Antibiotics ,Disease ,medicine.disease_cause ,lcsh:RC346-429 ,03 medical and health sciences ,Epilepsy ,0302 clinical medicine ,Developmental Neuroscience ,Streptococcus pneumoniae ,medicine ,lcsh:Neurology. Diseases of the nervous system ,business.industry ,medicine.disease ,Vaccination ,030104 developmental biology ,Immunology ,Perspective ,Ceftriaxone ,medicine.symptom ,business ,Meningitis ,030217 neurology & neurosurgery ,medicine.drug - Abstract
Pneumococcal meningitis is a highly lethal form of bacterial meningitis that occurs following brain infection by the Gram-positive cocci Streptococcus pneumoniae. Not only does it cause acute mortality, but pneumococcal meningitis also accounts for the highest proportion of survivors living with neurological sequelae, including behavioral disorders, cognitive deficits, hearing loss, motor impairment and epilepsy. More than 90 distinct pneumococcal serotypes have been identified worldwide based on their capsular compositions and serological responses. Serotype replacement continually poses great challenge to costly vaccination programs in developed countries (Koelman et al., 2020), this has therefore emphasized the need to develop new treatment strategies in addition to improving vaccine coverage. Various immunomodulatory agents, such as complement system inhibitors and matrix metalloproteinase inhibitors, have been shown to improve disease severity and mortality when tested in animal models (Bewersdorf et al., 2018). Nevertheless, given the evidence of long-term cognitive deficits and behavioral problems in patients who were clinically well recovered from pneumococcal meningitis, it remains unclear how the protection at the early inflammatory stage may translate into long-term functional recovery. With this in mind, we have established an integrated approach to investigate the interplay between acute host inflammatory response and ensuing neurological deficits in a mouse model of pneumococcal meningitis in animals that survive the lethal disease due to antibiotic ceftriaxone treatment. This has enabled the identification of a nexus between the toll-like receptors (TLRs) 2 and 4, interferon-gamma (IFN-γ) and the enzyme indoleamine 2,3-dioxygenase-1 (IDO-1) that contributes to enduring neurological impairments. Here, we will highlight the findings of our systematic studies in the hope of opening avenues for future research relevant to both meningitis as well as other neurological diseases.
- Published
- 2020
33. Quantitative Measurement of Cell-Nanoparticle Interactions Using Mass Cytometry
- Author
-
Andrew J, Mitchell, Angela, Ivask, and Yi, Ju
- Subjects
Metals ,Cells ,Humans ,Metal Nanoparticles ,Single-Cell Analysis ,Flow Cytometry ,Lanthanoid Series Elements ,Mass Spectrometry - Abstract
Mass cytometry is a technique that uses inductively coupled plasma mass spectrometry (ICP-MS) to quantify the isotopic composition of cells in suspension. Traditionally it has been used in conjunction with antibodies labeled with stable lanthanide isotopes to investigate cellular heterogeneity. Here we describe its use to quantify uptake of metal nanoparticles by cells in suspension.
- Published
- 2019
34. Correction to: Quantitative Measurement of Cell-Nanoparticle Interactions Using Mass Cytometry
- Author
-
Yi Ju, Angela Ivask, and Andrew J. Mitchell
- Subjects
medicine.anatomical_structure ,Computer science ,Cell ,Section (typography) ,medicine ,Mass cytometry ,Data science - Abstract
This chapter was inadvertently published with the acknowledgement section leaving out the following sentence: "This work received funding from South Australian Government PRIF program Project "International Cluster on Nanosafety" of Nicolas H. Voelcker and Enzo Lombi." This correction has been updated in the chapter.
- Published
- 2019
35. Quantitative Measurement of Cell-Nanoparticle Interactions Using Mass Cytometry
- Author
-
Andrew J. Mitchell, Yi Ju, and Angela Ivask
- Subjects
0303 health sciences ,Chromatography ,medicine.diagnostic_test ,Isotope ,Chemistry ,Nanoparticle ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Mass spectrometry ,Flow cytometry ,03 medical and health sciences ,Single-cell analysis ,medicine ,Mass cytometry ,0210 nano-technology ,Suspension (vehicle) ,Inductively coupled plasma mass spectrometry ,030304 developmental biology - Abstract
Mass cytometry is a technique that uses inductively coupled plasma mass spectrometry (ICP-MS) to quantify the isotopic composition of cells in suspension. Traditionally it has been used in conjunction with antibodies labeled with stable lanthanide isotopes to investigate cellular heterogeneity. Here we describe its use to quantify uptake of metal nanoparticles by cells in suspension.
- Published
- 2019
36. The Botany of Romanticism: Plants and the Exposition of Life
- Author
-
Andrew J. Mitchell
- Subjects
Literature ,Philosophy ,business.industry ,Hegelianism ,Romanticism ,business ,Order (virtue) ,Exposition (narrative) ,Epistemology - Abstract
German Romanticism is a thinking of life as exposed. Philosophical conceptions of botanical life are paradigmatic of this. Goethe, Schelling, and Hegel each address the plant in their respective philosophies of nature. This article traces the connections and divergences in their thinking of plants, focusing on the role of love (Goethe), lack (Hegel), and exposure (Schelling) in order to present the plant as a peculiarly apt figure for considerations of life as exposed.
- Published
- 2016
37. Antibody-induced neutrophil depletion prior to the onset of pneumococcal meningitis influences long-term neurological complications in mice
- Author
-
Lay Khoon Too, Andrew J. Mitchell, Nicholas H. Hunt, and Iain S. McGregor
- Subjects
0301 basic medicine ,Neutrophils ,medicine.drug_class ,Immunology ,Antibiotics ,Spatial Learning ,Motor Activity ,medicine.disease_cause ,Mice ,03 medical and health sciences ,Behavioral Neuroscience ,0302 clinical medicine ,Streptococcus pneumoniae ,medicine ,Animals ,Neutrophil extravasation ,Innate immune system ,Behavior, Animal ,biology ,Meningitis, Pneumococcal ,Endocrine and Autonomic Systems ,business.industry ,medicine.disease ,Mice, Inbred C57BL ,Disease Models, Animal ,030104 developmental biology ,Ceftriaxone ,biology.protein ,Cytokines ,Female ,Tumor necrosis factor alpha ,Antibody ,business ,Meningitis ,030217 neurology & neurosurgery ,medicine.drug - Abstract
During pneumococcal meningitis, clearance of bacteria by recruited neutrophils is crucial for host protection. However, these innate immune mechanisms are often insufficient and treatment with antibiotics is necessary to prevent death. Despite this antibiotic treatment, approximately half of all survivors suffer lifelong neurological problems. There is growing evidence indicating the harmful effects of neutrophils on CNS integrity. Therefore, the present study investigated the roles of neutrophils in the acute inflammatory response and the resulting long-term neuropsychological effects in murine pneumococcal meningitis. Long-term behavioural and cognitive functions in mice were measured using an automated IntelliCage system. Neutrophil depletion with antibody 1A8 as adjunctive therapy was shown to remarkably impair survival in meningitic C57BL/6J mice despite antibiotic (ceftriaxone) treatment. This was accompanied by increased bacterial load in the cerebrospinal fluid (CSF) and an increase in IL-1β, but decrease in TNF, within the CSF at 20h after bacterial inoculation. In the longer term, the surviving neutrophil-depleted post-meningitic (PM) mice displayed reduced diurnal hypolocomotion compared to PM mice treated with an isotype antibody. However, they showed nocturnal hyperactivity, and greater learning impairment in a patrolling task that is believed to depend upon an intact hippocampus. The data thus demonstrate two important mechanisms: 1. Neutrophil extravasation into the CNS during pneumococcal meningitis influences the pro-inflammatory response and is central to control of the bacterial load, an increase in which may lead to death. 2. Neutrophil-mediated changes in the acute inflammatory response modulate the neuropsychological sequelae in mice that survive pneumococcal meningitis.
- Published
- 2016
38. Donatella Di Cesare: Heidegger, die Juden, die Shoah (Heidegger Forum 12) und Peter Trawny, Andrew J. Mitchell (Hg.): Heidegger, die Juden, noch einmal (Heidegger Forum 11)
- Author
-
Andrew J. Mitchell, Reinhard Mehring, Trawny Peter, and Donatella Di Cesare
- Published
- 2016
39. Dietary copper effects survival of channel catfish challenged with Flavobacterium columnare
- Author
-
Andrew J. Mitchell, Steven D. Rawles, David L. Straus, Bradley D. Farmer, and Benjamin H. Beck
- Subjects
0301 basic medicine ,biology ,Columnaris disease ,04 agricultural and veterinary sciences ,Aquatic Science ,biology.organism_classification ,Microbiology ,Fishery ,03 medical and health sciences ,030104 developmental biology ,Flavobacterium columnare ,040102 fisheries ,0401 agriculture, forestry, and fisheries ,Dietary Copper ,Channel (broadcasting) ,Catfish - Published
- 2016
40. Heidegger’s Breakdown: Health and Healing Under the Care of Dr. V.E. von Gebsattel
- Author
-
Andrew J. Mitchell
- Subjects
Philosophy ,Medical profession ,Abandonment (emotional) ,medicine ,Biography ,Sociology ,medicine.disease ,Mental health ,Mental breakdown ,Epistemology - Abstract
In 1946 Heidegger suffered a mental breakdown and received treatment by Dr. Viktor Emil Freiherr von Gebsattel. I explore the themes of health and help in Heidegger’s work before and after his treatment. I begin with Heidegger’s views on health while Rector in 1933–34 (1) and his abandonment of these views by war’s end (2). A short while later, Heidegger’s breakdown occurs and the treatment under Gebsattel begins (3). Soon after his treatment, Heidegger lauds what he terms a “broken-down” thinking, and I examine his contribution to a 1958 Festschrift for Gebsattel to better articulate such a thinking (4). Lastly, I take up Heidegger’s remarks on the role of the medical profession in a technological age from a 1962 speech (5). In presenting this material, I hope to shed new light on a little known aspect of Heidegger’s career and biography and to situate philosophically his relationship with Dr. Gebsattel.
- Published
- 2016
41. Blood‒Brain Barrier Pathology and CNS Outcomes in
- Author
-
Belinda, Yau, Nicholas H, Hunt, Andrew J, Mitchell, and Lay Khoon, Too
- Subjects
Meningitis, Pneumococcal ,blood‒brain barrier ,Streptococcus ,meningitis ,Review ,pneumococcal ,infection ,Immunomodulation ,Streptococcus pneumoniae ,Blood-Brain Barrier ,inflammation ,Animals ,Humans ,pneumonia - Abstract
Streptococcus pneumoniae is a major meningitis-causing pathogen globally, bringing about significant morbidity and mortality, as well as long-term neurological sequelae in almost half of the survivors. Subsequent to nasopharyngeal colonisation and systemic invasion, translocation across the blood‒brain barrier (BBB) by S. pneumoniae is a crucial early step in the pathogenesis of meningitis. The BBB, which normally protects the central nervous system (CNS) from deleterious molecules within the circulation, becomes dysfunctional in S. pneumoniae invasion due to the effects of pneumococcal toxins and a heightened host inflammatory environment of cytokines, chemokines and reactive oxygen species intracranially. The bacteria‒host interplay within the CNS likely determines not only the degree of BBB pathological changes, but also host survival and the extent of neurological damage. This review explores the relationship between S. pneumoniae bacteria and the host inflammatory response, with an emphasis on the BBB and its roles in CNS protection, as well as both the acute and long-term pathogenesis of meningitis.
- Published
- 2018
42. The Question Concerning the Machine
- Author
-
Andrew J. Mitchell
- Subjects
Trace (semiology) ,Philosophy ,Reading (process) ,media_common.quotation_subject ,Exact relation ,Context (language use) ,Relation (history of concept) ,media_common ,Epistemology - Abstract
Heidegger’s technology notebooks in the late 1940s and early 1950s give us new insight into his thinking of technology by highlighting and emphasizing, like nowhere else in his oeuvre, the role of the machine therein. Across the notebooks, we find Heidegger struggling to articulate the exact relation between the machine and machination (in the 1930s and early 1940s), or the machine and positionality (late 1940s onward). The machine is ultimately something of a privileged example for helping us better understand this shift in Heidegger’s thinking as a whole across these volatile years. In this chapter, I trace this thinking of the machine as it emerges from Heidegger’s reading of Nietzsche (§1) and leads Heidegger to situate the machine in the context of machination (§2). After the war, the shift in Heidegger’s views of technology lead to a recontextualizing of the machine in terms of positionality (§3). With this, we arrive at Heidegger’s mature thinking of technology and the role of the machine therein. I conclude with some thoughts on the human’s relation to technology and the machine’s place in enabling this (§4).
- Published
- 2018
43. Noncatalytic chalcone isomerase-fold proteins in
- Author
-
Zhaonan, Ban, Hao, Qin, Andrew J, Mitchell, Baoxiu, Liu, Fengxia, Zhang, Jing-Ke, Weng, Richard A, Dixon, and Guodong, Wang
- Subjects
Flavonoids ,Prenylation ,food and beverages ,Plant Biology ,Flowers ,Sequence Analysis, DNA ,Biological Sciences ,chalcone synthase ,trichome ,PNAS Plus ,Mutation ,flavonoid ,chalcone isomerase-like ,Humulus ,Intramolecular Lyases ,Acyltransferases ,Metabolic Networks and Pathways ,Humulus lupulus ,Plant Proteins - Abstract
Significance Here, we identify two noncatalytic chalcone isomerase-fold proteins, which are critical for high-efficiency prenylchalcone production in Humulus lupulus. Our results provide insights into their evolutionary development from the ancestral noncatalytic fatty acid-binding chalcone isomerase-fold proteins to specialized auxiliary proteins supporting flavonoid biosynthesis in plants, and open up the possibility of producing high-value plant prenylchalcones using heterologous systems., Xanthohumol (XN) and demethylxanthohumol (DMX) are specialized prenylated chalconoids with multiple pharmaceutical applications that accumulate to high levels in the glandular trichomes of hops (Humulus lupulus L.). Although all structural enzymes in the XN pathway have been functionally identified, biochemical mechanisms underlying highly efficient production of XN have not been fully resolved. In this study, we characterized two noncatalytic chalcone isomerase (CHI)-like proteins (designated as HlCHIL1 and HlCHIL2) using engineered yeast harboring all genes required for DMX production. HlCHIL2 increased DMX production by 2.3-fold, whereas HlCHIL1 significantly decreased DMX production by 30%. We show that CHIL2 is part of an active DMX biosynthetic metabolon in hop glandular trichomes that encompasses a chalcone synthase (CHS) and a membrane-bound prenyltransferase, and that type IV CHI-fold proteins of representative land plants contain conserved function to bind with CHS and enhance its activity. Binding assays and structural docking uncover a function of HlCHIL1 to bind DMX and naringenin chalcone to stabilize the ring-open configuration of these chalconoids. This study reveals the role of two HlCHILs in DMX biosynthesis in hops, and provides insight into their evolutionary development from the ancestral fatty acid-binding CHI-fold proteins to specialized auxiliary proteins supporting flavonoid biosynthesis in plants.
- Published
- 2018
44. Acknowledgments
- Author
-
Andrew J. Mitchell
- Published
- 2018
45. Methodologies and approaches for the analysis of cell-nanoparticle interactions
- Author
-
Angela Ivask, Andrew J. Mitchell, Nicolas H. Voelcker, Enzo Lombi, Anzhela Malysheva, Ivask, Angela, Mitchell, Andrew J, Malysheva, Anzhela, Voelcker, Nicolas H, and Lombi, Enzo
- Subjects
silver nanoparticles ,Materials science ,Intracellular localization ,Cytological Techniques ,Biomedical Engineering ,Medicine (miscellaneous) ,Nanoparticle ,Bioengineering ,Nanotechnology ,structured illumination microscopy ,02 engineering and technology ,plasma-mass spectrometry ,010402 general chemistry ,01 natural sciences ,Mice ,enhanced raman-spectroscopy ,Animals ,Humans ,Cells, Cultured ,Microscopy ,transmission electron-microscopy ,021001 nanoscience & nanotechnology ,Cellular Structures ,0104 chemical sciences ,dark-field microscopy ,Nanotoxicology ,gold nanoparticles ,nano-bio interface ,Nanomedicine ,Nanoparticles ,particle icp-ms ,flow-cytometry ,0210 nano-technology - Abstract
How to study nanoparticle–cell interactions is the key question that puzzles researchers in the fields of nanomedicine as well as in nanotoxicology. In nanotoxicology, the amount of nanoparticles internalized by the cells or bound to the external surfaces of cells determines the toxic profile of those particles. In medical applications, cellular uptake and binding of medically effective nanoparticles decides their efficacy. Despite the importance of understanding the extent and mode of nanoparticle–cell interactions, these processes are underinvestigated, mainly due to the lack of suitable user-friendly methodologies. Here we discuss the advantages and limitations of currently available (and most advanced) microscopic, spectroscopic, and other bioanalytical methods that could be used to assess cell-nanoparticle interactions either qualitatively or quantitatively. Special emphasis is given to the methods that enable analysis and identification of nanoparticles at single-cell level, and allow intracellular localization and speciation analysis of nanoparticles. This article is categorized under: Nanotechnology Approaches to Biology > Cells at the Nanoscale Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials. Refereed/Peer-reviewed
- Published
- 2018
46. IRGM3 Contributes to Immunopathology and Is Required for Differentiation of Antigen-Specific Effector CD8 + T Cells in Experimental Cerebral Malaria
- Author
-
Wolfgang Weninger, Andrew J. Mitchell, Gregory Tullo, Belinda Yau, Nicholas H. Hunt, Carole A. Long, Patrick Bertolino, Ben Roediger, Gregory A. Taylor, Jintao Guo, Helen J. Ball, and James A. McQuillan
- Subjects
Chemokine ,Plasmodium berghei ,T cell ,Immunology ,Malaria, Cerebral ,Antigens, Protozoan ,CD8-Positive T-Lymphocytes ,Microbiology ,GTP Phosphohydrolases ,Interferon-gamma ,Mice ,Antigen ,GTP-Binding Proteins ,parasitic diseases ,medicine ,Animals ,Cytotoxic T cell ,Interferon gamma ,RNA, Messenger ,Chemokine CCL4 ,IRGs ,Chemokine CCL2 ,Cell Proliferation ,Chemokine CCL3 ,Inflammation ,Mice, Knockout ,biology ,Interleukin-6 ,Brain ,Cell Differentiation ,biology.organism_classification ,Adoptive Transfer ,Mice, Inbred C57BL ,Infectious Diseases ,medicine.anatomical_structure ,Interferon Type I ,biology.protein ,Parasitology ,Fungal and Parasitic Infections ,CD8 ,medicine.drug - Abstract
Gamma interferon (IFN-γ) drives antiparasite responses and immunopathology during infection with Plasmodium species. Immunity-related GTPases (IRGs) are a class of IFN-γ-dependent proteins that are essential for cell autonomous immunity to numerous intracellular pathogens. However, it is currently unknown whether IRGs modulate responses during malaria. We have used the Plasmodium berghei ANKA (PbA) model in which mice develop experimental cerebral malaria (ECM) to study the roles of IRGM1 and IRGM3 in immunopathology. Induction of mRNA for Irgm1 and Irgm3 was found in the brains and spleens of infected mice at times of peak IFN-γ production. Irgm3 −/− but not Irgm1 −/− mice were completely protected from the development of ECM, and this protection was associated with the decreased induction of inflammatory cytokines, as well as decreased recruitment and activation of CD8 + T cells within the brain. Although antigen-specific proliferation of transferred CD8 + T cells was not diminished compared to that of wild-type recipients following PbA infection, T cells transferred into Irgm3 −/− recipients showed a striking impairment of effector differentiation. Decreased induction of several inflammatory cytokines and chemokines (interleukin-6, CCL2, CCL3, and CCL4), as well as enhanced mRNA expression of type-I IFNs, was found in the spleens of Irgm3 −/− mice at day 4 postinfection. Together, these data suggest that protection from ECM pathology in Irgm3 −/− mice occurs due to impaired generation of CD8 + effector function. This defect is nonintrinsic to CD8 + T cells. Instead, diminished T cell responses most likely result from defective initiation of inflammatory responses in myeloid cells.
- Published
- 2015
47. Single Cell Level Quantification of Nanoparticle-Cell Interactions Using Mass Cytometry
- Author
-
Andrew J. Mitchell, Angela Ivask, Nicolas H. Voelcker, Enzo Lombi, Christopher M. Hope, Simon C. Barry, Ivask, Angela, Mitchell, Andrew J, Hope, Christopher M, Barry, Simon C, Lombi, Enzo, and Voelcker, Nicholas H
- Subjects
Silver ,T-Lymphocytes ,Analytical chemistry ,Nanoparticle ,Metal Nanoparticles ,02 engineering and technology ,cell proliferatio ,Mass spectrometry ,01 natural sciences ,Mass Spectrometry ,Analytical Chemistry ,Jurkat Cells ,Single-cell analysis ,Humans ,Mass cytometry ,Particle Size ,Inductively coupled plasma mass spectrometry ,cell culture ,nanotechnology ,Chemistry ,010401 analytical chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Nanotoxicology ,Biophysics ,Nanomedicine ,nanoparticles ,Single-Cell Analysis ,0210 nano-technology ,Intracellular - Abstract
Quantification of cell-associated nanoparticles (NPs) is a paramount question in both nanomedicine and nanotoxicology. Inductively coupled plasma mass spectrometry is a well-established method to resolve cell-associated (metal) NPs in bulk cell populations, however, such analysis at single cell level remains a challenge. Here we used mass cytometry, a technique that combines single cell analysis and time-of-flight mass spectrometry, to quantitatively analyze extra- and intracellular silver (Ag) in individual Ag NP exposed human T-lymphocytes. The results revealed significant population heterogeneity: for example, in lymphocytes exposed to 3 μg of 30 nm branched polyethylene imine coated Ag NPs/mL the extracellularly bound Ag varied from 79 to 560 fg and cellular uptake from 17 to 121 fg. Similar amplitude of heterogeneity was observed in cells exposed to various doses of Ag NPs with other sizes and surface coatings, demonstrating the importance of single cell analysis when studying NP-cell interactions. Although mass cytometry has some shortcomings such as inability to analyze potential transformation or dissolution of NPs in cells, we consider this method as the most promising for quantitative assessment of cell-NP interaction at single cell level. Refereed/Peer-reviewed
- Published
- 2017
48. Acute and residual effects in adolescent rats resulting from exposure to the novel synthetic cannabinoids AB-PINACA and AB-FUBINACA
- Author
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Jordyn Stuart, Michael Kassiou, Katie Wood, Samuel D. Banister, Iain S. McGregor, Richard C. Kevin, Andrew J. Mitchell, and Michael Moir
- Subjects
Male ,Cannabinoid receptor ,Indazoles ,medicine.medical_treatment ,Pharmacology ,01 natural sciences ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,AB-PINACA ,Receptor, Cannabinoid, CB1 ,AB-FUBINACA ,Synthetic cannabinoids ,medicine ,Animals ,Pharmacology (medical) ,Dronabinol ,Rats, Wistar ,Cannabinoid Receptor Agonists ,Memory Disorders ,business.industry ,Cannabinoids ,Illicit Drugs ,010401 analytical chemistry ,Valine ,Endocannabinoid system ,0104 chemical sciences ,Rats ,Psychiatry and Mental health ,chemistry ,Toxicity ,Cannabinoid ,business ,030217 neurology & neurosurgery ,Locomotion ,medicine.drug ,Endocannabinoids - Abstract
Synthetic cannabinoids (SCs) have rapidly proliferated as recreational drugs, and may present a substantial health risk to vulnerable populations. However, information on possible effects of long-term use is sparse. This study compared acute and residual effects of the popular indazole carboxamide SC compounds AB-PINACA and AB-FUBINACA in adolescent rats with ∆9-tetrahydrocannabinol (THC) and control treatments. Albino Wistar rats were injected (i.p.) with AB-PINACA or AB-FUBINACA every second day (beginning post-natal day (PND) 31), first at a low dose (0.2 mg/kg on 6 days) followed by a higher dose (1 mg/kg on a further 6 days). THC-treated rats received equivalent doses of 6 × 1 mg/kg and 6 × 5 mg/kg. During drug treatment, THC, AB-PINACA, and AB-FUBINACA decreased locomotor activity at high and low doses, increased anxiety-like behaviours and audible vocalisations, and reduced weight gain. Two weeks after dosing was completed, all cannabinoid pre-treated rats exhibited object recognition memory deficits. These were notably more severe in rats pre-treated with AB-FUBINACA. However, social interaction was reduced in the THC pre-treated group only. Six weeks post-dosing, plasma levels of cytokines interleukin (IL)-1α and IL-12 were reduced by AB-FUBINACA pre-treatment, while cerebellar endocannabinoids were reduced by THC and AB-PINACA pre-treatment. The acute effects of AB-PINACA and AB-FUBINACA were broadly similar to those of THC, suggesting that acute SC toxicity in humans may be modulated by dose factors, including inadvertent overdose and product contamination. However, some lasting residual effects of these different cannabinoid receptor agonists were subtly different, hinting at recruitment of different mechanisms of neuroadaptation.
- Published
- 2017
49. Comparative Effects of Copper Sulfate or Potassium Permanganate on Channel Catfish Concurrently Infected withFlavobacterium columnareandIchthyobodo necator
- Author
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Bradley D. Farmer, Andrew J. Mitchell, Benjamin H. Beck, S. Adam Fuller, L. Matt Barnett, and David L. Straus
- Subjects
Veterinary medicine ,Ecology ,Copper sulfate ,Aquatic Science ,Biology ,biology.organism_classification ,Parasite load ,Microbiology ,Potassium permanganate ,chemistry.chemical_compound ,chemistry ,Ictalurus ,Flavobacterium columnare ,Ichthyobodo necator ,Parasite hosting ,Catfish - Abstract
A study was conducted to compare the effects of two chemical therapeutants on channel catfish (CCF) Ictalurus punctatus concurrently infected with Flavobacterium columnare and Ichthyobodo necator. Copper sulfate (CuSO4) and potassium permanganate (KMnO4) were investigated for their ability to reduce the bacterial load, parasite load, and subsequent mortality. Treatment rates of CuSO4 or KMnO4 were 2.1 mg/L and 3.0 mg/L, respectively, and were applied at 24 h intervals on three consecutive days and control fish were untreated. Fin and gill samples were taken on day 4 (24 h after the final treatment) and day 10 (one week after the final treatment) for quantification of parasite and bacterial load. The survival rate of CuSO4-treated fish (73.0 %) was significantly different from the untreated control fish (41.5%). KMnO4-treated fish was (53.6%) and not significantly different from untreated control or CuSO4-treated fish. I. necator loads were significantly reduced by both CuSO4 and KMnO4, but only CuSO4 sign...
- Published
- 2014
50. Reduction of Experimental Cerebral Malaria and Its Related Proinflammatory Responses by the Novel Liposome-Basedβ-Methasone Nanodrug
- Author
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Jintao Guo, Judith H. Waknine-Grinberg, Yechezkel Barenholz, Jacob Golenser, and Andrew J. Mitchell
- Subjects
Chemokine ,Article Subject ,Plasmodium berghei ,Plasmodium falciparum ,Malaria, Cerebral ,lcsh:Medicine ,Inflammation ,Betamethasone ,General Biochemistry, Genetics and Molecular Biology ,Proinflammatory cytokine ,Mice ,Drug Delivery Systems ,Immune system ,Downregulation and upregulation ,medicine ,Animals ,Humans ,Th1-Th2 Balance ,General Immunology and Microbiology ,biology ,Microglia ,business.industry ,lcsh:R ,General Medicine ,medicine.disease ,Disease Models, Animal ,medicine.anatomical_structure ,Blood-Brain Barrier ,Cerebral Malaria ,Liposomes ,Immunology ,biology.protein ,Nanoparticles ,Chemokines ,medicine.symptom ,business ,Malaria ,Research Article - Abstract
Cerebral malaria (CM) is a severe complication of and a leading cause of death due toPlasmodium falciparuminfection. CM is likely the result of interrelated events, including mechanical obstruction due to parasite sequestration in the microvasculature, and upregulation of Th1 immune responses. In parallel, blood-brain-barrier (BBB) breakdown and damage or death of microglia, astrocytes, and neurons occurs. We found that a novel formulation of a liposome-encapsulated glucocorticosteroid,β-methasone hemisuccinate (nSSL-BMS), prevents experimental cerebral malaria (ECM) in a murine model and creates a survival time-window, enabling administration of an antiplasmodial drug before severe anemia develops. nSSL-BMS treatment leads to lower levels of cerebral inflammation, expressed by altered levels of corresponding cytokines and chemokines. The results indicate the role of integrated immune responses in ECM induction and show that the new steroidal nanodrug nSSL-BMS reverses the balance between the Th1 and Th2 responses in malaria-infected mice so that the proinflammatory processes leading to ECM are prevented. Overall, because of the immunopathological nature of CM, combined immunomodulator/antiplasmodial treatment should be considered for prevention/treatment of human CM and long-term cognitive damage.
- Published
- 2014
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