27 results on '"Quinton, M."'
Search Results
2. Camallanid nematodes from
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Ashlee P, Nofal, Quinton M, Dos Santos, Franz, Jirsa, and Annemariè, Avenant-Oldewage
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- 2022
3. The influence of signs of social class on compassionate responses to people in need
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Bennett, Callaghan, Quinton M, Delgadillo, and Michael W, Kraus
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General Psychology - Abstract
A field experiment (N = 4,536) examined how signs of social class influence compassionate responses to those in need. Pedestrians in two major cities in the United States were exposed to a confederate wearing symbols of relatively high or low social class who was requesting money to help the homeless. Compassionate responding was assessed by measuring the donation amount of the pedestrians walking past the target. Pedestrians gave more than twice (2.55 times) as much money to the confederate wearing higher-class symbols than they did to the one wearing lower-class symbols. A follow-up study (N = 504) exposed participants to images of the target wearing the same higher- or lower-class symbols and examined the antecedents of compassionate responding. Consistent with theorizing, higher-class symbols elicited perceptions of elevated competence, trustworthiness, similarity to the self, and perceived humanity compared to lower-class symbols. These results indicate that visible signs of social class influence judgments of others’ traits and attributes, as well as in decisions to respond compassionately to the needs of those who are suffering.
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- 2022
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4. Computational design of constitutively active cGAS
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Quinton M, Dowling, Hannah E, Volkman, Elizabeth E, Gray, Sergey, Ovchinnikov, Stephanie, Cambier, Asim K, Bera, Banumathi, Sankaran, Max R, Johnson, Matthew J, Bick, Alex, Kang, Daniel B, Stetson, and Neil P, King
- Abstract
Cyclic GMP-AMP synthase (cGAS) is a pattern recognition receptor critical for the innate immune response to intracellular pathogens, DNA damage, tumorigenesis and senescence. Binding to double-stranded DNA (dsDNA) induces conformational changes in cGAS that activate the enzyme to produce 2'-3' cyclic GMP-AMP (cGAMP), a second messenger that initiates a potent interferon (IFN) response through its receptor, STING. Here, we combined two-state computational design with informatics-guided design to create constitutively active, dsDNA ligand-independent cGAS (CA-cGAS). We identified CA-cGAS mutants with IFN-stimulating activity approaching that of dsDNA-stimulated wild-type cGAS. DNA-independent adoption of the active conformation was directly confirmed by X-ray crystallography. In vivo expression of CA-cGAS in tumor cells resulted in STING-dependent tumor regression, demonstrating that the designed proteins have therapeutically relevant biological activity. Our work provides a general framework for stabilizing active conformations of enzymes and provides CA-cGAS variants that could be useful as genetically encoded adjuvants and tools for understanding inflammatory diseases.
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- 2021
5. Engineering a Plant-Derived Astaxanthin Synthetic Pathway Into
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Quinton M, Allen, Vicente J, Febres, Bala, Rathinasabapathi, and José X, Chaparro
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astaxanthin ,Adonis aestivalis ,fungi ,Agrobacterium-mediated transformation ,Nicotiana benthamiana ,food and beverages ,Plant Science ,Brevundimonas sp. SD212 ,Original Research - Abstract
Carotenoids have been shown to be essential for human nutrition. Consumption of carotenoid-rich fruits and vegetables can reduce the risk of many diseases. The ketocarotenoid astaxanthin has become a commercially valuable compound due to its powerful antioxidant properties compared to other carotenoids. It is naturally produced in certain algae, bacteria, and the flowers of some species of the genus Adonis, although it is produced in such small quantities in these organisms that it is costly to extract. Chemical synthesis of this compound has also shown limited success with a high proportion of esterified forms of astaxanthin being produced, which decreases antioxidant properties by the conversion of hydroxyl groups to esters. Previously, transgenic astaxanthin-producing plants have been created using a β-carotene ketolase enzyme of either bacterial or algal origin. However, a novel astaxanthin pathway exists in the flowering plants of the genus Adonis which has not been utilized in the same manner. The pathway involves two unique enzymes, β-ring-4-dehydrogenase and 4-hydroxy-β-ring-4-dehydrogenase, which add the necessary hydroxyl and ketone groups to the rings of β-carotene. In the present study, Nicotiana benthamiana plants were transformed with chimeric constructs coding for these two enzymes. The regenerated, transgenic plants accumulate astaxanthin and their growth (height and weight) was unaffected, when compared to non-transformed N. benthamiana and to plants transformed with the bacterial β-carotene ketolase. The accumulation of astaxanthin also improved seedling survivability under harsh UV light, mitigated reactive oxygen accumulation, and provided a phenotype (color) that allowed the efficient identification and recovery of transgenic plants with and without selection.
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- 2021
6. Non-REM sleep facilitates consolidation of contextual fear memory through temporal coding among hippocampal neurons
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James Shaver, Michal Zochowski, Brittany C. Clawson, Sara J. Aton, Nicolette Ognjanovski, Bolaji Eniwaye, and Quinton M. Skilling
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Spike-timing-dependent plasticity ,musculoskeletal, neural, and ocular physiology ,Eye movement ,Hippocampus ,Biology ,Hippocampal formation ,Sleep in non-human animals ,Non-rapid eye movement sleep ,medicine.anatomical_structure ,nervous system ,Neuromodulation ,medicine ,Cholinergic ,Memory consolidation ,Neuroscience - Abstract
SummarySleep plays a critical role in memory consolidation, although the exact mechanisms mediating this process are unknown. Combining computational and in vivo experimental approaches, we test the hypothesis that reduced cholinergic input to the hippocampus during non-rapid eye movement (NREM) sleep generates stable spike timing relationships between neurons. We find that the order of firing among neurons during a period of NREM sleep reflects their relative firing rates during prior wake, and changes as a function of prior learning. We show that learning-dependent pattern formation (e.g. “replay”) in the hippocampus during NREM, together with spike timing dependent plasticity (STDP), restructures network activity in a manner similar to that observed in brain circuits across periods of sleep. This suggests that sleep actively promotes memory consolidation by switching the network from rate-based to firing phase-based information encoding.
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- 2020
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7. Lyophilization of an Adjuvanted Mycobacterium tuberculosis Vaccine in a Single-Chamber Pharmaceutical Cartridge
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Dawn M. Fedor, Quinton M. Dowling, Sylvain Cloutier, Sarah C. Parker, Michelle Archer, Lucien Barnes, Ryan M. Kramer, Thomas S. Vedvick, Simon Williams, and Christopher B. Fox
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0301 basic medicine ,Chemistry, Pharmaceutical ,medicine.medical_treatment ,Pharmaceutical Science ,Aquatic Science ,Vial ,Mycobacterium tuberculosis ,03 medical and health sciences ,Cartridge ,Freeze-drying ,Adjuvants, Immunologic ,Drug Discovery ,medicine ,Tuberculosis Vaccines ,Ecology, Evolution, Behavior and Systematics ,Chromatography ,Ecology ,biology ,Glass Vial ,Chemistry ,General Medicine ,biology.organism_classification ,Vaccination ,Freeze Drying ,030104 developmental biology ,Pharmaceutical Preparations ,Tuberculosis vaccines ,Agronomy and Crop Science ,Adjuvant - Abstract
Although substantial effort has been made in the development of next-generation recombinant vaccine systems, maintenance of a cold chain is still typically required and remains a critical challenge in effective vaccine distribution. The ability to engineer alternative containment systems that improve distribution and administration represents potentially significant enhancements to vaccination strategies. In this work, we evaluate the ability to successfully lyophilize a previously demonstrated thermostable tuberculosis vaccine formulation (ID93 + GLA-SE) in a cartridge format compared to a traditional vial container format. Due to differences in the shape of the container formats, a novel apparatus was developed to facilitate lyophilization in a cartridge. Following lyophilization, the lyophilizate was assessed visually, by determining residual moisture content, and by collecting melting profiles. Reconstituted formulations were assayed for particle size, protein presence, and GLA content. Based on assessment of the lyophilizate, the multicomponent vaccine was successfully lyophilized in both formats. Also, the physicochemical properties of the major components in the formulation, including antigen and adjuvant, were retained after lyophilization in either format. Ultimately, this study demonstrates that complex formulations can be lyophilized in alternative container formats to the standard pharmaceutical glass vial, potentially helping to increase the distribution of vaccines.
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- 2016
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8. Surgical Techniques
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Quinton M. Hatch and Scott R. Steele
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- 2018
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9. Early Resumption of β Blockers Is Associated with Decreased Atrial Fibrillation after Noncardiothoracic and Nonvascular Surgery: A Cohort Analysis
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Ashish K, Khanna, Douglas F, Naylor, Amanda J, Naylor, Edward J, Mascha, Jing, You, Eric M, Reville, Quinton M, Riter, Murtaza, Diwan, Andrea, Kurz, and Daniel I, Sessler
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Male ,Incidence ,Adrenergic beta-Antagonists ,Length of Stay ,Middle Aged ,Cohort Studies ,Postoperative Complications ,Surgical Procedures, Operative ,Atrial Fibrillation ,Humans ,Female ,Propensity Score ,Aged ,Retrospective Studies - Abstract
WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Beta (β) blockers reduce the risk of postoperative atrial fibrillation and should be restarted after surgery, but it remains unclear when best to resume β blockers postoperatively. The authors thus evaluated the relationship between timing of resumption of β blockers and atrial fibrillation in patients recovering from noncardiothoracic and nonvascular surgery.The authors evaluated 8,201 adult β-blocker users with no previous history of atrial fibrillation who stayed at least two nights after noncardiothoracic and nonvascular surgery as a retrospective observational cohort. After propensity score matching on baseline and intraoperative variables, 1,924 patients who did resume β blockers by the end of postoperative day 1 were compared with 973 patients who had not resumed by that time on postoperative atrial fibrillation using logistic regression. A secondary matched analysis compared 3,198 patients who resumed β blockers on the day of surgery with 3,198 who resumed thereafter.Of propensity score-matched patients who resumed β blockers by end of postoperative day 1, 4.9% (94 of 1,924) developed atrial fibrillation, compared with 7.0% (68 of 973) of those who resumed thereafter (adjusted odds ratio, 0.69; 95% CI, 0.50-0.95; P = 0.026). Patients who resumed β blockers on day of surgery had an atrial fibrillation incidence of 4.9% versus 5.8% for those who started thereafter (odds ratio, 0.84; 95% CI, 0.67-1.04; P = 0.104).Resuming β blockers in chronic users by the end of the first postoperative day may be associated with lower odds of in-hospital atrial fibrillation. However, there seems to be little advantage to restarting on the day of surgery itself.
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- 2018
10. Development of a thermostable nanoemulsion adjuvanted vaccine against tuberculosis using a design-of-experiments approach
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Christopher B. Fox, Quinton M. Dowling, Michelle Archer, Dawn M. Fedor, Po-Wei D. Huang, Alicia M. Schwartz, Natasha Dubois Cauwelaert, Thomas S. Vedvick, Elyse A. Beebe, Mark T. Orr, and Ryan M. Kramer
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0301 basic medicine ,controlled temperature chain ,medicine.medical_treatment ,Chemistry, Pharmaceutical ,Pharmaceutical Science ,Pharmacology ,International Journal of Nanomedicine ,Drug Discovery ,Tuberculosis Vaccines ,Original Research ,Thermostability ,Immunity, Cellular ,biology ,Chemistry ,Immunogenicity ,Temperature ,General Medicine ,Hydrogen-Ion Concentration ,Lipids ,Drug product ,Emulsions ,Female ,Adjuvant ,Tuberculosis ,lyophilization ,Biophysics ,Bioengineering ,Biomaterials ,Mycobacterium tuberculosis ,Excipients ,03 medical and health sciences ,adjuvant ,Antigen ,Adjuvants, Immunologic ,Nephelometry and Turbidimetry ,GRAS ,medicine ,Animals ,Particle Size ,formulation development ,Organic Chemistry ,biology.organism_classification ,medicine.disease ,Dynamic Light Scattering ,Mice, Inbred C57BL ,design of experiments ,030104 developmental biology ,Freeze Drying ,Antibody Formation ,Nanoparticles - Abstract
Ryan M Kramer, Michelle C Archer, Mark T Orr, Natasha Dubois Cauwelaert, Elyse A Beebe, Po-wei D Huang, Quinton M Dowling, Alicia M Schwartz, Dawn M Fedor, Thomas S Vedvick, Christopher B Fox Infectious Disease Research Institute, Seattle, WA, USA Background: Adjuvants have the potential to increase the efficacy of protein-based vaccines but need to be maintained within specific temperature and storage conditions. Lyophilization can be used to increase the thermostability of protein pharmaceuticals; however, no marketed vaccine that contains an adjuvant is currently lyophilized, and lyophilization of oil-in-water nanoemulsion adjuvants presents a specific challenge. We have previously demonstrated the feasibility of lyophilizing a candidate adjuvanted protein vaccine against Mycobacterium tuberculosis (Mtb), ID93 + GLA-SE, and the subsequent improvement of thermostability; however, further development is required to prevent physicochemical changes and degradation of the TLR4 agonist glucopyranosyl lipid adjuvant formulated in an oil-in-water nanoemulsion (SE). Materials and methods: In this study, we took a systematic approach to the development of a thermostable product by first identifying compatible solution conditions and stabilizing excipients for both antigen and adjuvant. Next, we applied a design-of-experiments approach to identify stable lyophilized drug product formulations. Results: We identified specific formulations that contain disaccharide or a combination of disaccharide and mannitol that can achieve substantially improved thermostability and maintain immunogenicity in a mouse model when tested in accelerated and real-time stability studies. Conclusion: These efforts will aid in the development of a platform formulation for use with other similar vaccines. Keywords: adjuvant, lyophilization, tuberculosis, formulation development, design of experiments, controlled temperature chain, GRAS
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- 2018
11. An abdominal computed tomography may be safe in selected hypotensive trauma patients with positive Focused Assessment with Sonography in Trauma examination
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Mackenzie R. Cook, John B. Holcomb, Mohammad H. Rahbar, Erin E. Fox, Louis H. Alarcon, Eileen M. Bulger, Karen J. Brasel, Martin A. Schreiber, Deborah J. del Junco, Bryan A. Cotton, Charles E. Wade, Jiajie Zhang, Nena Matijevic, Yu Bai, Weiwei Wang, Jeanette Podbielski, Sarah J. Duran, Ruby Benjamin-Garner, Robert J. Reynolds, Xuan Zhang, Aisha Dickerson, Elizabeth S. Camp, Marily Elopre, Quinton M. Hatch, Michelle Scerbo, Zerremi Caga-Anan, Christopher E. White, Kimberly L. Franzen, Elsa C. Coates, Pamela Walsh, Samantha J. Underwood, Jodie Curren, Mitchell J. Cohen, M. Margaret Knudson, Mary Nelson, Mariah S. Call, Peter Muskat, Jay A. Johannigman, Bryce R.H. Robinson, Richard Branson, Dina Gomaa, Cendi Dahl, Andrew B. Peitzman, Stacy D. Stull, Mitch Kampmeyer, Barbara J. Early, Helen L. Shnol, Samuel J. Zolin, Sarah B. Sears, John G. Myers, Ronald M. Stewart, Rick L. Sambucini, Marianne Gildea, Mark DeRosa, Rachelle Jonas, Janet McCarthy, Herbert A. Phelan, Joseph P. Minei, Elizabeth Carroll, Patricia Klotz, and Keir J. Warner
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medicine.medical_specialty ,business.industry ,Major trauma ,medicine.medical_treatment ,General Medicine ,Odds ratio ,medicine.disease ,Confidence interval ,Surgery ,medicine.anatomical_structure ,Blood pressure ,mental disorders ,Medicine ,Abdomen ,Radiology ,business ,Prospective cohort study ,Pelvis ,Dialysis - Abstract
Background Positive Focused Assessment with Sonography in Trauma examination and hypotension often indicate urgent surgery. An abdomen/pelvis computed tomography (apCT) may allow less invasive management but the delay may be associated with adverse outcomes. Methods Patients in the Prospective Observational Multicenter Major Trauma Transfusion study with hypotension and a positive Focused Assessment with Sonography in Trauma (HF+) examination who underwent a CT (apCT+) were compared with those who did not. Results Of the 92 HF+ identified, 32 (35%) underwent apCT during initial evaluation and apCT was associated with decreased odds of an emergency operation (odds ratio .11, 95% confidence interval .001 to .116) and increased odds of angiographic intervention (odds ratio 14.3, 95% confidence interval 1.5 to 135). There was no significant difference in 30-day mortality or need for dialysis. Conclusions An apCT in HF+ patients is associated with reduced odds of emergency surgery, but not mortality. Select HF+ patients can safely undergo apCT to obtain clinically useful information.
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- 2015
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12. Quantitative Measurement of Toll-like Receptor 4 Agonists Adsorbed to Alhydrogel® by Fourier Transform Infrared-Attenuated Total Reflectance Spectroscopy
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Quinton M. Dowling, Alicia M. Schwartz, Christopher B. Fox, Thomas S. Vedvick, and Ryan M. Kramer
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Absorption spectroscopy ,Chemistry ,medicine.medical_treatment ,Inorganic chemistry ,Analytical chemistry ,Pharmaceutical Science ,Aluminum Hydroxide ,Toll-Like Receptor 4 ,symbols.namesake ,Lipid A ,Fourier transform ,Adsorption ,Glucosides ,Attenuated total reflection ,Spectroscopy, Fourier Transform Infrared ,medicine ,symbols ,Molecule ,Fourier transform infrared spectroscopy ,Spectroscopy ,Adjuvant - Abstract
Aluminum salts have a long history as safe and effective vaccine adjuvants. In addition, aluminum salts have high adsorptive capacities for vaccine antigens and adjuvant molecules, for example, Toll-like receptor 4 (TLR4) agonists. However, the physicochemical properties of aluminum salts make direct quantitation of adsorbed molecules challenging. Typical methods for quantifying adsorbed molecules require advanced instrumentation, extreme sample processing, often destroy the sample, or rely on an indirect measurement. A simple, direct, and quantitative method for analysis of adsorbed adjuvant molecules is needed. This report presents a method utilizing Fourier transform infrared spectroscopy with a ZnSe-attenuated total reflectance attachment to directly measure low levels (30 μg/mL) of TLR4 agonists adsorbed on aluminum salts with minimal sample preparation.
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- 2015
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13. Effects of reciprocal inhibitory coupling in model neurons
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Wolfgang Stein, Quinton M. Skilling, and Epaminondas Rosa
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Statistics and Probability ,Models, Neurological ,Biological neuron model ,Synaptic Transmission ,General Biochemistry, Genetics and Molecular Biology ,medicine ,Computer Simulation ,Neurons ,Physics ,Quantitative Biology::Neurons and Cognition ,Applied Mathematics ,Gap junction ,Reciprocal inhibition ,Central pattern generator ,Neural Inhibition ,General Medicine ,Coupling (electronics) ,medicine.anatomical_structure ,nervous system ,Modeling and Simulation ,Synapses ,Central Pattern Generators ,Neuron ,Entrainment (chronobiology) ,Neuroscience ,Reciprocal - Abstract
Central pattern generators are neuron networks that produce vital rhythmic motor outputs such as those observed in mastication, walking and breathing. Their activity patterns depend on the tuning of their intrinsic ionic conductances, their synaptic interconnectivity and entrainment by extrinsic neurons. The influence of two commonly found synaptic connectivities – reciprocal inhibition and electrical coupling – are investigated here using a neuron model with subthreshold oscillation capability, in different firing and entrainment regimes. We study the dynamics displayed by a network of a pair of neurons with various firing regimes, coupled by either (i) only reciprocal inhibition or by (ii) electrical coupling first and then reciprocal inhibition. In both scenarios a range of coupling strengths for the reciprocal inhibition is tested, and in general the neuron with the lower firing rate stops spiking for strong enough inhibitory coupling, while the faster neuron remains active. However, in scenario (ii) the originally slower neuron stops spiking at weaker inhibitory coupling strength, suggesting that the electrical coupling introduces an element of instability to the two-neuron network.
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- 2015
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14. Appendiceal Neoplasms
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Quinton M. Hatch
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Appendiceal Neoplasms ,Gastroenterology ,Humans ,Female ,General Medicine ,Middle Aged ,Prognosis - Published
- 2017
15. Functional network stability and average minimal distance - A framework to rapidly assess dynamics of functional network representations
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Chenguang Li, Quinton M. Skilling, Sara J. Aton, Jiaxing Wu, Nicolette Ognjanovski, Daniel Maruyama, and Michal Zochowski
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0301 basic medicine ,Computer science ,Computation ,Models, Neurological ,Stability (learning theory) ,Action Potentials ,Machine learning ,computer.software_genre ,Article ,03 medical and health sciences ,0302 clinical medicine ,Neural Pathways ,Animals ,Learning ,Computer Simulation ,Set (psychology) ,Complement (set theory) ,Neurons ,Artificial neural network ,business.industry ,Bootstrapping ,General Neuroscience ,Brain ,Signal Processing, Computer-Assisted ,Fear ,Network dynamics ,Electrodes, Implanted ,Mice, Inbred C57BL ,030104 developmental biology ,Metric (mathematics) ,Synapses ,Artificial intelligence ,Neural Networks, Computer ,business ,computer ,030217 neurology & neurosurgery ,Algorithms - Abstract
Background Recent advances in neurophysiological recording techniques have increased both the spatial and temporal resolution of data. New methodologies are required that can handle large data sets in an efficient manner as well as to make quantifiable, and realistic, predictions about the global modality of the brain from under-sampled recordings. New method To rectify both problems, we first propose an analytical modification to an existing functional connectivity algorithm, Average Minimal Distance (AMD), to rapidly capture functional network connectivity. We then complement this algorithm by introducing Functional Network Stability (FuNS), a metric that can be used to quickly assess the global network dynamic changes over time, without being constrained by the activities of a specific set of neurons. Results We systematically test the performance of AMD and FuNS (1) on artificial spiking data with different statistical characteristics, (2) from spiking data generated using a neural network model, and (3) using in vivo data recorded from mouse hippocampus during fear learning. Our results show that AMD and FuNS are able to monitor the change in network dynamics during memory consolidation. Comparison with other methods AMD outperforms traditional bootstrapping and cross-correlation (CC) methods in both significance and computation time. Simultaneously, FuNS provides a reliable way to establish a link between local structural network changes, global dynamics of network-wide representations activity, and behavior. Conclusions The AMD-FuNS framework should be universally useful in linking long time-scale, global network dynamics and cognitive behavior.
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- 2017
16. Elimination of the cold-chain dependence of a nanoemulsion adjuvanted vaccine against tuberculosis by lyophilization
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Rhea N. Coler, Christopher B. Fox, Quinton M. Dowling, Mark T. Orr, John D. Laurance, Steven G. Reed, Anthony L. Desbien, Thomas S. Vedvick, Ryan M. Kramer, Lucien Barnes, and Elyse A. Beebe
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Tuberculosis ,T-Lymphocytes ,medicine.medical_treatment ,Pharmaceutical Science ,Vial ,Article ,Mycobacterium tuberculosis ,Leukocyte Count ,Mice ,Adjuvants, Immunologic ,Antigen ,parasitic diseases ,medicine ,Animals ,Tuberculosis Vaccines ,Lung ,Antigens, Bacterial ,B-Lymphocytes ,biology ,Temperature ,virus diseases ,medicine.disease ,biology.organism_classification ,Antibodies, Bacterial ,Virology ,Bacterial Load ,Nanostructures ,Mice, Inbred C57BL ,Freeze Drying ,Immunology ,biology.protein ,Emulsions ,Female ,Antibody ,Tuberculosis vaccines ,Adjuvant ,Spleen ,Malaria - Abstract
Next-generation rationally-designed vaccine adjuvants represent a significant breakthrough to enable development of vaccines against challenging diseases including tuberculosis, HIV, and malaria. New vaccine candidates often require maintenance of a cold-chain process to ensure long-term stability and separate vials to enable bedside mixing of antigen and adjuvant. This presents a significant financial and technological barrier to worldwide implementation of such vaccines. Herein we describe the development and characterization of a tuberculosis vaccine comprised of both antigen and adjuvant components that are stable in a single vial at sustained elevated temperatures. Further this vaccine retains the ability to elicit both antibody and TH1 responses against the vaccine antigen and protect against experimental challenge with Mycobacterium tuberculosis. These results represent a significant breakthrough in the development of vaccine candidates that can be implemented throughout the world without being hampered by the necessity of a continuous cold chain or separate adjuvant and antigen vials.
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- 2014
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17. Modulating Potency: Physicochemical Characteristics are a Determining Factor of TLR4-Agonist Nanosuspension Activity
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Jeff Guderian, James Chesko, Christopher B. Fox, Magdalini Moutaftsi, Quinton M. Dowling, Thomas S. Vedvick, Ryan M. Kramer, and Sandra J. Sivananthan
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Agonist ,1,2-Dipalmitoylphosphatidylcholine ,Chemical Phenomena ,Surface Properties ,medicine.drug_class ,Acylation ,medicine.medical_treatment ,Pharmaceutical Science ,Excipient ,Disaccharides ,Lipid A ,Adjuvants, Immunologic ,Suspensions ,In vivo ,medicine ,Humans ,Transition Temperature ,Potency ,Particle Size ,Phosphorylation ,Blood Cells ,Myristates ,Chemistry ,Osmolar Concentration ,Biological activity ,In vitro ,Nanostructures ,Toll-Like Receptor 4 ,Drug Combinations ,Biochemistry ,Cytokines ,lipids (amino acids, peptides, and proteins) ,Adjuvant ,Interferon-gamma Release Tests ,medicine.drug - Abstract
Activity of adjuvanted vaccines is difficult to predict in vitro and in vivo. The wide compositional and conformational range of formulated adjuvants, from aluminum salts to oil-in-water emulsions, makes comparisons between physicochemical and immunological properties difficult. Even within a formulated adjuvant class, excipient selection and concentration can alter potency and physicochemical properties of the mixture. Complete characterization of physicochemical properties of adjuvanted vaccine formulations and relationship to biological response is necessary to move beyond a guess-and-check paradigm toward directed development. Here we present a careful physicochemical characterization of a two-component nanosuspension containing synthetic TLR-4 agonist glucopyranosyl lipid adjuvant (GLA) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) at various molar ratios. Physicochemical properties were compared with potency, as measured by stimulation of cytokine production in human whole blood. We found a surprising, nonlinear relationship between physicochemical properties and GLA-DPPC ratios that corresponded well with changes in biological activity. We discuss these data in light of the current understanding of TLR4 activation and the conformation-potency relationship in development of adjuvanted vaccines.
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- 2014
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18. Critical Dynamics Mediate Learning of New Distributed Memory Representations in Neuronal Networks
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Michal Zochowski, Sara J. Aton, Quinton M. Skilling, and Nicolette Ognjanovski
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memory and learning ,Theoretical computer science ,Computer science ,Critical phenomena ,General Physics and Astronomy ,lcsh:Astrophysics ,Article ,03 medical and health sciences ,0302 clinical medicine ,lcsh:QB460-466 ,Attractor ,Biological neural network ,lcsh:Science ,030304 developmental biology ,0303 health sciences ,Consolidation (soil) ,critical phenomena ,Network dynamics ,lcsh:QC1-999 ,memory consolidation ,Criticality ,lcsh:Q ,Distributed memory ,Memory consolidation ,lcsh:Physics ,030217 neurology & neurosurgery - Abstract
We explore the possible role of network dynamics near a critical point in the storage of new information in silico and in vivo, and show that learning and memory may rely on neuronal network features mediated by the vicinity of criticality. Using a mean-field, attractor-based model, we show that new information can be consolidated into attractors through state-based learning in a dynamical regime associated with maximal susceptibility at the critical point. Then, we predict that the subsequent consolidation process results in a shift from critical to sub-critical dynamics to fully encapsulate the new information. We go on to corroborate these findings using analysis of rodent hippocampal CA1 activity during contextual fear memory (CFM) consolidation. We show that the dynamical state of the CA1 network is inherently poised near criticality, but the network also undergoes a shift towards sub-critical dynamics due to successful consolidation of the CFM. Based on these findings, we propose that dynamical features associated with criticality may be universally necessary for storing new memories.
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- 2019
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19. Modifications in Network Structure and Excitability May Drive Differential Activity-Dependent Integration of Granule Cells into Dentate Gyrus Circuits During Normal and Pathological Adult Neurogenesis
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James P. Roach, Leonard M. Sander, Quinton M. Skilling, Alison L. Althaus, Geoffrey G. Murphy, and Michal Zochowski
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0301 basic medicine ,Dentate gyrus ,Neurogenesis ,Granule (cell biology) ,Subventricular zone ,Entorhinal cortex ,medicine.disease ,03 medical and health sciences ,Epilepsy ,030104 developmental biology ,0302 clinical medicine ,medicine.anatomical_structure ,medicine ,Excitatory postsynaptic potential ,Psychology ,Neuroscience ,Pathological ,030217 neurology & neurosurgery - Abstract
The granule cells born during adult neurogenesis in the dentate gyrus (DG) are thought to be involved in formation of new memory representations. At the same time, they are implicated in exacerbation of the pathology during epilepsy. Moreover, it has been found that patterns of their integration into DG circuits are significantly different in health and pathology. The aim of this contribution is to identify network-wide structural and dynamical mechanisms underlying this differential incorporation of the newly born cells, as well as resulting changes in activity patterns in the network. We show that, on the one hand, decreased network-wide inhibition and long-range excitatory connectivity alone can result in significant changes in augmentation patterns of new cells, such as increased survival rate of new cells, emergence of globally synchronized activity patterns, and decreased correlation between network drive and location of the surviving cells. On the other hand, we show that changes in excitability, namely phase response curves, of newly born cells can also lead to emergence of globally coherent activity patterns that are not responsive to local input properties. These results indicate that both of these mechanisms can be responsible for reorganization of neuronal pathological integration during adult neurogenesis.
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- 2017
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20. Quantification of Multiple Components of Complex Aluminum-Based Adjuvant Mixtures by Using Fourier Transform Infrared Spectroscopy and Partial Least Squares Modeling
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Quinton M, Dowling and Ryan M, Kramer
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Adjuvants, Immunologic ,Spectroscopy, Fourier Transform Infrared ,Least-Squares Analysis ,Mass Spectrometry ,Aluminum - Abstract
Fourier transform infrared (FTIR) spectroscopy is widely used in the pharmaceutical industry for process monitoring, compositional quantification, and characterization of critical quality attributes in complex mixtures. Advantages over other spectroscopic measurements include ease of sample preparation, quantification of multiple components from a single measurement, and the ability to quantify optically opaque samples. This method describes the use of a multivariate model for quantifying a TLR4 agonist (GLA) adsorbed onto aluminum oxyhydroxide (Alhydrogel
- Published
- 2016
21. Particle Sizing of Nanoparticle Adjuvant Formulations by Dynamic Light Scattering (DLS) and Nanoparticle Tracking Analysis (NTA)
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Michelle Y, Chan, Quinton M, Dowling, Sandra J, Sivananthan, and Ryan M, Kramer
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Adjuvants, Immunologic ,Emulsions ,Particle Size ,Dynamic Light Scattering - Abstract
Dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA) are two orthogonal and complementary methods of measuring size of particles in a sample. These technologies use the theory of Brownian motion by analyzing the random changes of light intensity scattered by particles in solution. Both techniques can be used to characterize particle size distribution of proteins and formulations in the nanometer to low micron range.Each method has benefits over the other. DLS is a quick and simple measurement that is ideal for monodisperse particles and can also analyze a distribution of particles over a wide range of sizes. NTA provides a size distribution that is less susceptible to the influence of a few large particles, and has the added benefit of being able to measure particle concentration. Here we describe methods for measuring the particle size and concentration of an oil-in-water nanoemulsion.
- Published
- 2016
22. Particle Sizing of Nanoparticle Adjuvant Formulations by Dynamic Light Scattering (DLS) and Nanoparticle Tracking Analysis (NTA)
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Quinton M. Dowling, Ryan M. Kramer, Michelle Y. Chan, and Sandra J. Sivananthan
- Subjects
0301 basic medicine ,Materials science ,Dispersity ,Nanoparticle ,Nanoparticle tracking analysis ,02 engineering and technology ,021001 nanoscience & nanotechnology ,03 medical and health sciences ,Light intensity ,030104 developmental biology ,Dynamic light scattering ,Particle-size distribution ,Particle ,Particle size ,0210 nano-technology ,Biological system - Abstract
Dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA) are two orthogonal and complementary methods of measuring size of particles in a sample. These technologies use the theory of Brownian motion by analyzing the random changes of light intensity scattered by particles in solution. Both techniques can be used to characterize particle size distribution of proteins and formulations in the nanometer to low micron range.Each method has benefits over the other. DLS is a quick and simple measurement that is ideal for monodisperse particles and can also analyze a distribution of particles over a wide range of sizes. NTA provides a size distribution that is less susceptible to the influence of a few large particles, and has the added benefit of being able to measure particle concentration. Here we describe methods for measuring the particle size and concentration of an oil-in-water nanoemulsion.
- Published
- 2016
- Full Text
- View/download PDF
23. Thorough Study of Reactivity of Various Compound Classes toward the Folin−Ciocalteu Reagent
- Author
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Grant W. Wangila, Quinton M. Bryant, Jace D. Everette, Yvonne A. Abbey, Ashlee M. Green, and Richard B. Walker
- Subjects
chemistry.chemical_classification ,Dihydroxyacetone ,General Chemistry ,Ascorbic acid ,Antioxidants ,Article ,Amino acid ,chemistry.chemical_compound ,chemistry ,Reagent ,Thiol ,Organic chemistry ,Indicators and Reagents ,Reactivity (chemistry) ,Phenols ,Organic Chemicals ,Folin–Ciocalteu reagent ,General Agricultural and Biological Sciences - Abstract
A thorough study was done to test the reactivity of the Folin-Ciocalteu (F-C) reagent toward various compound classes. Over 80 compounds were tested. Compound classes included phenols, thiols, vitamins, amino acids, proteins, nucleotide bases, unsaturated fatty acids, carbohydrates, organic acids, inorganic ions, metal complexes, aldehydes, and ketones. All phenols, proteins, and thiols tested were reactive toward the reagent. Many vitamin derivatives were also reactive, as were the inorganic ions Fe(+2), Mn(2+), I(-), and SO(3)(2-). Other compounds showing reactivity included the nucleotide base guanine and the trioses glyceraldehyde and dihydroxyacetone. Copper complexation enhanced the reactivity of salicylate derivatives toward the reagent, whereas zinc complexation did not. Several amino acids and sugars that were reported to be reactive toward the F-C reagent in earlier studies were found not to be reactive in this study, at least in the concentrations used. Reaction kinetics of each compound with the F-C reagent were also measured. Most compounds tested showed a biphasic kinetic pattern with half-lives under 1 min. Trolox and ascorbic acid displayed a rapid monophasic pattern in which the reaction reached end point within 1 min. In summary, this study has shown that the F-C reagent is significantly reactive toward other compounds besides phenols. As other investigators have suggested, the F-C assay should be seen as a measure of total antioxidant capacity rather than phenolic content. Because phenolics are the most abundant antioxidants in most plants, it gives a rough approximation of total phenolic content in most cases.
- Published
- 2010
- Full Text
- View/download PDF
24. Working together: interactions between vaccine antigens and adjuvants
- Author
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Christopher B. Fox, Thomas S. Vedvick, Ryan M. Kramer, Lucien Barnes, and Quinton M. Dowling
- Subjects
biology ,business.industry ,medicine.medical_treatment ,Aluminum salts ,Reviews ,Vaccine antigen ,Vaccine Stability ,Vaccine Potency ,Immune system ,Antigen ,Immunology ,biology.protein ,medicine ,Antibody ,business ,Adjuvant - Abstract
The development of vaccines containing adjuvants has the potential to enhance antibody and cellular immune responses, broaden protective immunity against heterogeneous pathogen strains, enable antigen dose sparing, and facilitate efficacy in immunocompromised populations. Nevertheless, the structural interplay between antigen and adjuvant components is often not taken into account in the published literature. Interactions between antigen and adjuvant formulations should be well characterized to enable optimum vaccine stability and efficacy. This review focuses on the importance of characterizing antigen–adjuvant interactions by summarizing findings involving widely used adjuvant formulation platforms, such as aluminum salts, emulsions, lipid vesicles, and polymer-based particles. Emphasis is placed on the physicochemical basis of antigen–adjuvant associations and the appropriate analytical tools for their characterization, as well as discussing the effects of these interactions on vaccine potency.
- Published
- 2014
25. Mechanistic determinates of the acute coagulopathy of trauma (ACoT) in patients requiring emergency surgery
- Author
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Sherry L, Sixta, Quinton M, Hatch, Nena, Matijevic, Charles E, Wade, John B, Holcomb, and Bryan A, Cotton
- Subjects
Original Article - Abstract
Introduction: The development of acute coagulopathy of trauma (ACoT) is associated with a significant increase in mortality. However, the contributory mechanisms behind ACoT have yet to be clearly defined. The purpose of this study was to evaluate the influence of multiple variables, including base deficit and injury severity, on development of ACoT within a subset of critically ill trauma patients. Methods: A retrospective review of all trauma laparotomies between 01/2004-12/2009 was performed. ACoT (+) was defined as an arrival INR ≥1.5, ACoT (-) defined as INR
- Published
- 2012
26. REACTIVITY OF VARIOUS COMPOUND CLASSES TOWARDS THE FOLIN-CIOCALTEU REAGENT
- Author
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Richard B. Walker, Jace D. Everette, Quinton M. Bryant, Ashlee M. Green, Yvonne A. Abbey, Grant W. Wangila, and Olga Tarasenko
- Subjects
chemistry.chemical_classification ,Antioxidant ,Chemistry ,medicine.medical_treatment ,Ascorbic acid ,Amino acid ,chemistry.chemical_compound ,Lowry protein assay ,Reagent ,medicine ,Organic chemistry ,Phenols ,Trolox ,Folin–Ciocalteu reagent - Abstract
The Folin‐Ciocalteu assay has been used for over 80 years for the detection and quantitation of phenols. A modification of it, called the Lowry assay, is used for the quantitation of proteins. It has been commonly reported that the Folin‐Ciocalteu reagent, which is a complex mixture containing sodium molybdate and sodium tungstate, is reactive towards other antioxidants besides phenols. However, until now, no one has done experiments to test this hypothesis. In our study, we tested the reactivity of the reagent towards over 70 compounds. Compound classes included phenols, thiols, vitamins, amino acids, proteins, nucleotide bases, unsaturated fatty acids, carbohydrates, organic acids, inorganic ions, aldehydes and ketones. All phenols, proteins and thiols tested were reactive towards the reagent. Other compounds which showed reactivity included guanine, glyceraldehyde, dihydroxyacetone, tyrosine, tryptophan, cysteine, ascorbic acid, Trolox, retinoic acid, pyridoxine, Fe+2, Mn+2, I− and SO3−2. In summary, our study showed that the Folin‐Ciocalteu reagent is significantly reactive towards other compounds besides phenols. Therefore, it should be seen as a measure of total antioxidant capacity rather than phenolic content. It would be useful as a general antioxidant assay for measuring antioxidant capacities of compounds of biomedical interest.
- Published
- 2010
- Full Text
- View/download PDF
27. VIII.— Animal temperature as a part of the problem of evolution
- Author
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Quinton, M.
- Abstract
n/a
- Published
- 1896
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