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332 results on '"Ellis, Michael J."'

4. A macrophage-based screen identifies antibacterial compounds selective for intracellular Salmonella Typhimurium.

Author

Ellis, Michael J, Tsai, Caressa N, Johnson, Jarrod W, French, Shawn, Elhenawy, Wael, Porwollik, Steffen, Andrews-Polymenis, Helene, McClelland, Michael, Magolan, Jakob, Coombes, Brian K, and Brown, Eric D

Subjects
Cell Membrane, Macrophages, Animals, Mice, Inbred C57BL, Humans, Mice, Salmonella typhimurium, Salmonella Infections, Disease Models, Animal, Metergoline, Anti-Bacterial Agents, Microscopy, Atomic Force, Treatment Outcome, Microbial Sensitivity Tests, Drug Evaluation, Preclinical, Gene Deletion, Female, Methicillin-Resistant Staphylococcus aureus, High-Throughput Screening Assays, RAW 264.7 Cells, Infectious Diseases, Digestive Diseases, Emerging Infectious Diseases, Prevention, Vaccine Related, Foodborne Illness, Infection, Inbred C57BL, Disease Models, Animal, Microscopy, Atomic Force, Drug Evaluation, Preclinical, MD Multidisciplinary
Abstract

Salmonella Typhimurium (S. Tm) establishes systemic infection in susceptible hosts by evading the innate immune response and replicating within host phagocytes. Here, we sought to identify inhibitors of intracellular S. Tm replication by conducting parallel chemical screens against S. Tm growing in macrophage-mimicking media and within macrophages. We identify several compounds that inhibit Salmonella growth in the intracellular environment and in acidic, ion-limited media. We report on the antimicrobial activity of the psychoactive drug metergoline, which is specific against intracellular S. Tm. Screening an S. Tm deletion library in the presence of metergoline reveals hypersensitization of outer membrane mutants to metergoline activity. Metergoline disrupts the proton motive force at the bacterial cytoplasmic membrane and extends animal survival during a systemic S. Tm infection. This work highlights the predictive nature of intracellular screens for in vivo efficacy, and identifies metergoline as a novel antimicrobial active against Salmonella.

Published
2019

7. Validation of Tau Antibodies for Use in Western Blotting and Immunohistochemistry

Author

Ellis, Michael J., primary, Lekka, Christiana, additional, Tulmin, Hanna, additional, O’Brien, Darragh P., additional, Dhayal, Shalinee, additional, Zeissler, Marie-Louise, additional, Knudsen, Jakob G., additional, Kessler, Benedikt M., additional, Morgan, Noel G., additional, Todd, John A., additional, Richardson, Sarah J., additional, and Stefana, M. Irina, additional

Published
2023
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15. Reply

Author

Ellis, Michael J., Ritchie, Lesley, McDonald, Patrick, and Russell, Kelly

Published
2018
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29. Current Use and Future Considerations for Concussion Telemedicine Healthcare in Canada

Author

Ellis, Michael J., Normand, Heather, Gargaro, Judith, Bayley, Mark, and Russell, Kelly

Abstract

ABSTRACT:Objective:To examine the use of telemedicine among Canadian concussion providers and clinics before and after the COVID-19 pandemic onset and identify barriers and facilitators for future use.Methods:Ninety-nine concussion clinics and healthcare providers across Canada that offered one or more clinical concussion-related service were identified using standardized online searches and approached to complete a cross-sectional online survey.Results:Thirty clinics or providers completed the survey and two completed subsections of the survey (response rate of 32.3%). Only 28.1% of respondents indicated that they used telemedicine to provide care prior to the COVID-19 pandemic. Providers most commonly using telemedicine prior to the pandemic were occupational therapists and physicians, while the most commonly used services were in-person videoconferencing and eConsultation. Most respondents (87%) indicated their clinic’s use of telemedicine changed following the onset of the COVID-19 pandemic including new use of in-person video-conferencing, telephone calls, and eConsultation. Ninety-three percent indicated that they would consider using telemedicine to provide care to their concussion patients once the pandemic was over. Barriers needed to be overcome to facilitate use or greater use of telemedicine-based services were the inability to conduct a complete physical examination, lack of appropriate reimbursement, lack of start-up, and maintenance funding and medico-legal risk.Conclusion:Telemedicine was used by a minority of Canadian concussion clinics and providers prior to the COVID-19 pandemic but was rapidly adopted by many facilities. This study provides important insight into the factors that must be considered to optimize use of telemedicine in concussion care in the future.

Published
2023
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33. Sport-Related Structural Brain Injury and Return to Play: Systematic Review and Expert Insight

Author

Zuckerman, Scott L, primary, Yengo-Kahn, Aaron M, additional, Tang, Alan R, additional, Bailes, Julian E, additional, Beauchamp, Kathryn, additional, Berger, Mitchel S, additional, Bonfield, Christopher M, additional, Camarata, Paul J, additional, Cantu, Robert C, additional, Davis, Gavin A, additional, Ellenbogen, Richard G, additional, Ellis, Michael J, additional, Feuer, Hank, additional, Guazzo, Eric, additional, Harris, Odette A, additional, Heppner, Peter, additional, Honeybul, Stephen, additional, Manley, Geoff, additional, Maroon, Joseph C, additional, Miele, Vincent J, additional, Nahed, Brian V, additional, Okonkwo, David O, additional, Oppenlander, Mark E, additional, Petty, Jerry, additional, Sabin, H Ian, additional, Samadani, Uzma, additional, Sherburn, Eric W, additional, Sheridan, Mark, additional, Tator, Charles H, additional, Theodore, Nicholas, additional, Timmons, Shelly D, additional, Woodworth, Graeme F, additional, Solomon, Gary S, additional, and Sills, Allen K, additional

Published
2021
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34. Inhibition of Spleen Tyrosine Kinase Attenuates Allergen-Mediated Airway Constriction

Author

Moy, Lily Y., Jia, Yanlin, Caniga, Michael, Lieber, Gissela, Gil, Malgorzata, Fernandez, Xiomara, Sirkowski, Erich, Miller, Richard, Alexander, Jessica P., Lee, Hyun-Hee, Shin, John D., Ellis, Michael J., Chen, Hongmin, Wilhelm, Alan, Yu, Hongshi, Vincent, Stella, Chapman, Richard W., Kelly, Nancy, Hickey, Emily, Abraham, William M., Northrup, Alan, Miller, Thomas, Houshyar, Hani, and Crackower, Michael A.

Published
2013
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41. Clinical Outcomes of Pediatric Acute Sport- and Non-Sport-Related Concussions

Author

Ballinger, Karen, McGuinty, Duncan, Girardin, Richard, Zerkee, Leanne, Ellis, Michael J., and Russell, Kelly

Abstract

ABSTRACT:Objectives:The objectives were to examine clinical characteristics, length of recovery, and the prevalence of delayed physician-documented recovery, compare clinical outcomes among those with sport-related concussion (SRC) and non-sport-related concussion (nSRC), and identify risk factors for delayed recovery.Methods:Included patients (8–18 years) were assessed ≤14 days post-injury at a multidisciplinary concussion program and diagnosed with an acute SRC or nSRC. Physician-documented clinical recovery was defined as returning to pre-injury symptom status, attending full-time school without symptoms, completing Return-to-Sport strategy as needed, and normal physical examination. Delayed physician-documented recovery was defined as >28 days post-injury.Results:Four hundred and fifteen patients were included (77.8% SRC). There was no difference in loss of consciousness (SRC: 9.9% vs nSRC: 13.0%, p= 0.39) or post-traumatic amnesia (SRC: 24.1% vs SRC: 31.5%, p= 0.15) at the time of injury or any differences in median Post-Concussion Symptom Scale scores (SRC: 20 vs nSRC: 23, p= 0.15) at initial assessment. Among those with complete clinical follow-up, the median physician-documented clinical recovery was 20 days (SRC: 19 vs nSRC: 23; p= 0.37). There was no difference in the proportion of patients who developed delayed physician-documented recovery (SRC: 27.7% vs nSRC: 36.1%; p= 0.19). Higher initial symptom score increased the risk of delayed physician-documented recovery (IRR: 1.39; 95% CI: 1.29, 1.49). Greater material deprivation and social deprivation were associated with an increased risk of delayed physician-documented recovery.Conclusions:Most pediatric concussion patients who undergo early medical assessment and complete follow-up appear to make a complete clinical recovery within 4 weeks, regardless of mechanism.

Published
2022
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44. Early Subthreshold Aerobic Exercise for Sport-Related Concussion

Author

Leddy, John J., primary, Haider, Mohammad N., additional, Ellis, Michael J., additional, Mannix, Rebekah, additional, Darling, Scott R., additional, Freitas, Michael S., additional, Suffoletto, Heidi N., additional, Leiter, Jeff, additional, Cordingley, Dean M., additional, and Willer, Barry, additional

Published
2019
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46. RNA surveillance by uridylation-dependent RNA decay inSchizosaccharomyces pombe

Author

Chung, Christina Z, primary, Jaramillo, Julia E, additional, Ellis, Michael J, additional, Bour, Daniel Y N, additional, Seidl, Lauren E, additional, Jo, David H S, additional, Turk, Matthew A, additional, Mann, Mitchell R, additional, Bi, Yumin, additional, Haniford, David B, additional, Duennwald, Martin L, additional, and Heinemann, Ilka U, additional

Published
2019
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50. Riboregulation of Bacterial Transposons

Author

Ellis, Michael J

Subjects
transposon, Bacterial genetics, IS10/Tn10, IS200, sRNA, Molecular Biology, Hfq
Abstract

Bacterial transposons typically exist in a mutually beneficial relationship with the host cell. Limited transposition can benefit the host while also ensuring the survival of the element. An important component of this relationship is that transposition must be tightly regulated. In this thesis I explore ways that the host and transposon each control transposition in E. coli and provide evidence that a transposon can also control host gene expression in S. enterica Typhimurium. Post-transcriptional regulation with small non-coding RNAs (sRNA) has emerged as a key way that bacteria respond to stress and regulate many cellular processes. The RNA-binding protein Hfq is the nexus of sRNA regulatory networks and acts by promoting base-pairing interactions between sRNAs and their target mRNAs. Previous work found that Hfq is a potent negative regulator of IS10 transposition in E. coli and suggested that Hfq inhibited transposase translation using an IS10-encoded sRNA (RNA-OUT) as well as an undefined mechanism that was independent of RNA-OUT. I show that Hfq promotes base-pairing between RNA-OUT and IS10 transposase mRNA (RNA-IN) by melting the secondary structure of both RNAs to expose residues involved in intermolecular base-pairing. I also investigated how Hfq can repress translation of RNA-IN in the absence of RNA-OUT and demonstrate that Hfq-binding to an mRNA can directly repress translation in the absence of any sRNA. The data suggested Hfq may regulate other transposons and I show that the unrelated IS200 element is also subject to Hfq regulation. In contrast to the IS10 system, Hfq represses IS200 transposase (tnpA) translation completely independent of the IS200-encoded sRNA (art200). Translation initiation on tnpA is inhibited >350-fold by the cooperation of Hfq, art200, and an RNA structural element in the tnpA 5’UTR illustrating how host- and transposon-encoded factors can coordinate to repress transposition. Lastly, I demonstrate that tnpA is processed to produce an sRNA that alters transcript abundance >2-fold for 73 S. enterica Typhimurium genes, which provides a new twist on our understanding of host-transposon interactions. Taken together, this work suggests that RNA transactions play an important role in governing host-transposon relationships in bacteria.

Published
2016

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