1,604 results on '"Gavin E"'
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2. Electrical Conductivity, Thermo-Mechanical Properties, and Cytotoxicity of Poly(3,4-Ethylenedioxythiophene):Poly(Styrene Sulfonate) (PEDOT:PSS)/Sulfonated Polyurethane Blends
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Gagan Kaur, Gavin E. Collis, Raju Adhikari, and Pathiraja Gunatillake
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conductive composites ,polymeric films ,ionic ,segmented ,biocompatibility ,synthesis ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
Electrically conductive polymeric materials have recently garnered significant interest from researchers due to their potential applications in the biomedical field, including medical implants, tissue engineering, flexible electronic devices, and biosensors. Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is considered the most successful conducting polymer due to its higher electrical conductivity and chemical stability, but it suffers from limited solubility in common organic solvents, poor mechanical properties, and low biocompatibility. An area of tremendous interest is in combining PEDOT:PSS with another polymer to form a blend or composite material in order to access the beneficial properties of both materials. However, the hydrophilic nature of PEDOT:PSS makes it difficult to produce composites with non-polar polymers. In order to overcome these problems, we have specifically designed and synthesized two new sulfonated polyurethanes (PUS) with high sulfonic acid functionality. The two polyurethanes, one water-soluble (PUS1) and one water-insoluble (PUS2), were used to make blends with two commercially available PEDOT:PSS formulations (CleviosTM FET and PH1000). Solvent cast films on glass substrates were made from water-soluble PEDOT:PSS/PUS1 blends while free-standing films of PEDOT:PSS/PUS2 blends were fabricated by compression-moulding. Ethylene glycol was used as conductivity enhancer, which showed an increase in the conductivity by several orders of magnitude in most of the compositions investigated. The highest conductivity of 438 S cm−1 was achieved for the blend with 80 wt% of PEDOT:PSS (PH1000) in PUS1.
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- 2024
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3. The plasma degradome reflects later development of NASH fibrosis after liver transplant
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Jiang Li, Toshifumi Sato, María Hernández-Tejero, Juliane I. Beier, Khaled Sayed, Panayiotis V. Benos, Daniel W. Wilkey, Abhinav Humar, Michael L. Merchant, Andres Duarte-Rojo, and Gavin E. Arteel
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Medicine ,Science - Abstract
Abstract Although liver transplantation (LT) is an effective therapy for cirrhosis, the risk of post-LT NASH is alarmingly high and is associated with accelerated progression to fibrosis/cirrhosis, cardiovascular disease and decreased survival. Lack of risk stratification strategies hampers early intervention against development of post-LT NASH fibrosis. The liver undergoes significant remodeling during inflammatory injury. During such remodeling, degraded peptide fragments (i.e., ‘degradome’) of the ECM and other proteins increase in plasma, making it a useful diagnostic/prognostic tool in chronic liver disease. To investigate whether liver injury caused by post-LT NASH would yield a unique degradome profile that is predictive of severe post-LT NASH fibrosis, a retrospective analysis of 22 biobanked samples from the Starzl Transplantation Institute (12 with post-LT NASH after 5 years and 10 without) was performed. Total plasma peptides were isolated and analyzed by 1D-LC–MS/MS analysis using a Proxeon EASY-nLC 1000 UHPLC and nanoelectrospray ionization into an Orbitrap Elite mass spectrometer. Qualitative and quantitative peptide features data were developed from MSn datasets using PEAKS Studio X (v10). LC–MS/MS yielded ~ 2700 identifiable peptide features based on the results from Peaks Studio analysis. Several peptides were significantly altered in patients that later developed fibrosis and heatmap analysis of the top 25 most significantly changed peptides, most of which were ECM-derived, clustered the 2 patient groups well. Supervised modeling of the dataset indicated that a fraction of the total peptide signal (~ 15%) could explain the differences between the groups, indicating a strong potential for representative biomarker selection. A similar degradome profile was observed when the plasma degradome patterns were compared being obesity sensitive (C57Bl6/J) and insensitive (AJ) mouse strains. The plasma degradome profile of post-LT patients yielded stark difference based on later development of post-LT NASH fibrosis. This approach could yield new “fingerprints” that can serve as minimally-invasive biomarkers of negative outcomes post-LT.
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- 2023
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4. The Transcription Factor Mohawk Facilitates Skeletal Muscle Repair via Modulation of the Inflammatory Environment
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Cherie Alissa Lynch, Sofia A. Acosta, Douglas M. Anderson, Gavin E. Rogers, Jeanne Wilson-Rawls, and Alan Rawls
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Mohawk ,muscle repair ,inflammation ,macrophage ,cytokine ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Efficient repair of skeletal muscle relies upon the precise coordination of cells between the satellite cell niche and innate immune cells that are recruited to the site of injury. The expression of pro-inflammatory cytokines and chemokines such as TNFα, IFNγ, CXCL1, and CCL2, by muscle and tissue resident immune cells recruits neutrophils and M1 macrophages to the injury and activates satellite cells. These signal cascades lead to highly integrated temporal and spatial control of muscle repair. Despite the therapeutic potential of these factors for improving tissue regeneration after traumatic and chronic injuries, their transcriptional regulation is not well understood. The transcription factor Mohawk (Mkx) functions as a repressor of myogenic differentiation and regulates fiber type specification. Embryonically, Mkx is expressed in all progenitor cells of the musculoskeletal system and is expressed in human and mouse myeloid lineage cells. An analysis of mice deficient for Mkx revealed a delay in postnatal muscle repair characterized by impaired clearance of necrotic fibers and smaller newly regenerated fibers. Further, there was a delay in the expression of inflammatory signals such as Ccl2, Ifnγ, and Tgfß. This was coupled with impaired recruitment of pro-inflammatory macrophages to the site of muscle damage. These studies demonstrate that Mkx plays a critical role in adult skeletal muscle repair that is mediated through the initial activation of the inflammatory response.
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- 2024
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5. Protein painting reveals pervasive remodeling of conserved proteostasis machinery in response to pharmacological stimuli
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Dezerae Cox, Angelique R. Ormsby, Gavin E. Reid, and Danny M. Hatters
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Biology (General) ,QH301-705.5 - Abstract
Abstract The correct spatio-temporal organization of the proteome is essential for cellular homeostasis. However, a detailed mechanistic understanding of this organization and how it is altered in response to external stimuli in the intact cellular environment is as-yet unrealized. ‘Protein painting methods provide a means to address this gap in knowledge by monitoring the conformational status of proteins within cells at the proteome-wide scale. Here, we demonstrate the ability of a protein painting method employing tetraphenylethene maleimide (TPE-MI) to reveal proteome network remodeling in whole cells in response to a cohort of commonly used pharmacological stimuli of varying specificity. We report specific, albeit heterogeneous, responses to individual stimuli that coalesce on a conserved set of core cellular machineries. This work expands our understanding of proteome conformational remodeling in response to cellular stimuli, and provides a blueprint for assessing how these conformational changes may contribute to disorders characterized by proteostasis imbalance.
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- 2022
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6. Hidden information on protein function in censuses of proteome foldedness
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Dezerae Cox, Ching-Seng Ang, Nadinath B. Nillegoda, Gavin E. Reid, and Danny M. Hatters
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Science - Abstract
Proteomics can define features of proteome foldedness by assessing the reactivity of surface exposed amino acids. Here, the authors show that such exposure patterns yield insight to structural changes in chaperones as they bind to unfolded proteins in urea-denatured mammalian cell lysate.
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- 2022
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7. Closing the Loop on LIB Waste: A Comparison of the Current Challenges and Opportunities for the U.S. and Australia towards a Sustainable Energy Future
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Gavin E. Collis, Qiang Dai, Joanne S. C. Loh, Albert Lipson, Linda Gaines, Yanyan Zhao, and Jeffrey Spangenberger
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battery value chain ,lithium-ion battery recycling ,black mass ,critical materials ,sustainability ,circular economy ,Environmental sciences ,GE1-350 - Abstract
Many countries have started their transition to a net-zero economy. Lithium-ion batteries (LIBs) play an ever-increasing role towards this transition as a rechargeable energy storage medium. Initially, LIBs were developed for consumer electronics and portable devices but have seen dramatic growth in their use in electric vehicles (EVs) and via the gradual uptake in battery energy storage systems (BESSs) over the last decade. As such, critical metals (Li, Co, Ni, and Mn) and chemicals (polymers, electrolytes, Cu, Al, PVDF, LiPF6, LiBF4, and graphite) needed for LIBs are currently in great demand and are susceptible to global supply shortages. Dramatic increases in raw material prices, coupled with predicted exponential growth in global demand (e.g., United States graphite demand from 2022 7000 t to ~145,000 t), means that LIBs will not be sustainable if only sourced from raw materials. LIBs degrade over time. When their performance can no longer meet the requirement of their intended application (e.g., EVs in the 8–12 year range), opportunities exist to extract and recover battery materials for re-use in new batteries or to supply other industrial chemical sectors. This paper compares the challenges, barriers, opportunities, and successes of the United States of America and Australia as they transition to renewable energy storage and develop a battery supply chain to support a circular economy around LIBs.
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- 2023
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8. Fibrosis resolution in the mouse liver: Role of Mmp12 and potential role of calpain 1/2
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Toshifumi Sato, Kimberly Z. Head, Jiang Li, Christine E. Dolin, Daniel Wilkey, Nolan Skirtich, Katelyn Smith, Dylan D. McCreary, Sylvia Liu, Juliane I. Beier, Aatur D. Singhi, Ryan M. McEnaney, Michael L. Merchant, and Gavin E. Arteel
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MMP-12 ,Elastin ,Fibrosis ,Biology (General) ,QH301-705.5 - Abstract
Although most work has focused on resolution of collagen ECM, fibrosis resolution involves changes to several ECM proteins. The purpose of the current study was twofold: 1) to examine the role of MMP12 and elastin; and 2) to investigate the changes in degraded proteins in plasma (i.e., the “degradome”) in a preclinical model of fibrosis resolution. Fibrosis was induced by 4 weeks carbon tetrachloride (CCl4) exposure, and recovery was monitored for an additional 4 weeks. Some mice were treated with daily MMP12 inhibitor (MMP408) during the resolution phase. Liver injury and fibrosis was monitored by clinical chemistry, histology and gene expression. The release of degraded ECM peptides in the plasma was analyzed using by 1D-LC-MS/MS, coupled with PEAKS Studio (v10) peptide identification. Hepatic fibrosis and liver injury rapidly resolved in this mouse model. However, some collagen fibrils were still present 28d after cessation of CCl4. Despite this persistent collagen presence, expression of canonical markers of fibrosis were also normalized. The inhibition of MMP12 dramatically delayed fibrosis resolution under these conditions. LC-MS/MS analysis identified that several proteins were being degraded even at late stages of fibrosis resolution. Calpains 1/2 were identified as potential new proteases involved in fibrosis resolution. CONCLUSION. The results of this study indicate that remodeling of the liver during recovery from fibrosis is a complex and highly coordinated process that extends well beyond the degradation of the collagenous scar. These results also indicate that analysis of the plasma degradome may yield new insight into the mechanisms of fibrosis recovery, and by extension, new “theragnostic” targets. Lastly, a novel potential role for calpain activation in the degradation and turnover of proteins was identified.
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- 2023
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9. Environmental toxicant-induced maladaptive mitochondrial changes: A potential unifying mechanism in fatty liver disease?
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Regina D. Schnegelberger, Anna L. Lang, Gavin E. Arteel, and Juliane I. Beier
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Organochlorines ,Metals ,Persistent organic pollutants ,TASH ,Liver disease ,Hepatotoxicity ,Therapeutics. Pharmacology ,RM1-950 - Abstract
Occupational and environmental exposures to industrial chemicals are well known to cause hepatotoxicity and liver injury. However, despite extensive evidence showing that exposure can lead to disease, current research approaches and regulatory policies fail to address the possibility that subtle changes caused by low level exposure to chemicals may also enhance preexisting conditions. In recent years, the conceptual understanding of the contribution of environmental chemicals to liver disease has progressed significantly. Mitochondria are often target of toxicity of environmental toxicants resulting in multisystem disorders involving different cells, tissues, and organs. Here, we review persistent maladaptive changes to mitochondria in response to environmental toxicant exposure as a mechanism of hepatotoxicity. With better understanding of the mechanism(s) and risk factors that mediate the initiation and progression of toxicant-induced liver disease, rational targeted therapy can be developed to better predict risk, as well as to treat or prevent this disease.
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- 2021
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10. Environmental exposure as a risk-modifying factor in liver diseases: Knowns and unknowns
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Juliane I. Beier and Gavin E. Arteel
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Hepatic injury ,Exposomics ,Liver disease ,Drug-induced liver injury ,Alcoholic liver disease ,Non-alcoholic liver disease ,Therapeutics. Pharmacology ,RM1-950 - Abstract
Liver diseases are considered to predominantly possess an inherited or xenobiotic etiology. However, inheritance drives the ability to appropriately adapt to environmental stressors, and disease is the culmination of a maladaptive response. Thus “pure” genetic and “pure” xenobiotic liver diseases are modified by each other and other factors, identified or unknown. The purpose of this review is to highlight the knowledgebase of environmental exposure as a potential risk modifying agent for the development of liver disease by other causes. This exercise is not to argue that all liver diseases have an environmental component, but to challenge the assumption that the current state of our knowledge is sufficient in all cases to conclusively dismiss this as a possibility. This review also discusses key new tools and approaches that will likely be critical to address this question in the future. Taken together, identifying the key gaps in our understanding is critical for the field to move forward, or at the very least to “know what we don't know.”
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- 2021
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11. Obese female mice do not exhibit overt hyperuricemia despite hepatic steatosis and impaired glucose tolerance
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Sara E. Lewis, Lihua Li, Marco Fazzari, Sonia R. Salvatore, Jiang Li, Emily A. Hileman, Brooke A. Maxwell, Francisco J. Schopfer, Gavin E. Arteel, Nicholas K.H. Khoo, and Eric E. Kelley
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Uric acid ,Xanthine oxidoreductase ,Female mice ,Diet-induced obesity ,Hepatic steatosis ,Impaired glucose tolerance ,Biochemistry ,QD415-436 - Abstract
Recent reports have clearly demonstrated a tight correlation between obesity and elevated circulating uric acid levels (hyperuricemia). However, nearly all preclinical work in this area has been completed with male mice, leaving the field with a considerable gap in knowledge regarding female responses to obesity and hyperuricemia. This deficiency in sex as a biological variable extends beyond unknowns regarding uric acid (UA) to several important comorbidities associated with obesity including nonalcoholic fatty liver disease (NAFLD). To attempt to address this issue, herein we describe both phenotypic and metabolic responses to diet-induced obesity (DIO) in female mice. Six-week-old female C57BL/6J mice were fed a high-fat diet (60% calories derived from fat) for 32 weeks. The DIO female mice had significant weight gain over the course of the study, higher fasting blood glucose, impaired glucose tolerance, and elevated plasma insulin levels compared to age-matched on normal chow. While these classic indices of DIO and NAFLD were observed such as increased circulating levels of ALT and AST, there was no difference in circulating UA levels. Obese female mice also demonstrated increased hepatic triglyceride (TG), cholesterol, and cholesteryl ester. In addition, several markers of hepatic inflammation were significantly increased. Also, alterations in the expression of redox-related enzymes were observed in obese mice compared to lean controls including increases in extracellular superoxide dismutase (Sod3), heme oxygenase (Ho)-1, and xanthine dehydrogenase (Xdh). Interestingly, hepatic UA levels were significantly elevated (∼2-fold) in obese mice compared to their lean counterparts. These data demonstrate female mice assume a similar metabolic profile to that reported in several male models of obesity in the context of alterations in glucose tolerance, hepatic steatosis, and elevated transaminases (ALT and AST) in the absence of hyperuricemia affirming the need for further study.
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- 2022
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12. The Proteome and Lipidome of Extracellular Vesicles from Haemonchus contortus to Underpin Explorations of Host–Parasite Cross–Talk
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Tao Wang, Tiana F. Koukoulis, Laura J. Vella, Huaqi Su, Adityas Purnianto, Shuai Nie, Ching-Seng Ang, Guangxu Ma, Pasi K. Korhonen, Aya C. Taki, Nicholas A. Williamson, Gavin E. Reid, and Robin B. Gasser
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parasitic nematode ,Haemonchus contortus ,proteomics ,lipidomics ,LC-MS/MS ,host-parasite interactions ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Many parasitic worms have a major adverse impact on human and animal populations worldwide due to the chronicity of their infections. There is a growing body of evidence indicating that extracellular vesicles (EVs) are intimately involved in modulating (suppressing) inflammatory/immune host responses and parasitism. As one of the most pathogenic nematodes of livestock animals, Haemonchus contortus is an ideal model system for EV exploration. Here, employing a multi-step enrichment process (in vitro culture, followed by ultracentrifugation, size exclusion and filtration), we enriched EVs from H. contortus and undertook the first comprehensive (qualitative and quantitative) multi-omic investigation of EV proteins and lipids using advanced liquid chromatography–mass spectrometry and informatics methods. We identified and quantified 561 proteins and 446 lipids in EVs and compared these molecules with those of adult worms. We identified unique molecules in EVs, such as proteins linked to lipid transportation and lipid species (i.e., sphingolipids) associated with signalling, indicating the involvement of these molecules in parasite-host cross-talk. This work provides a solid starting point to explore the functional roles of EV-specific proteins and lipids in modulating parasite-host cross-talk, and the prospect of finding ways of disrupting or interrupting this relationship to suppress or eliminate parasite infection.
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- 2023
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13. Exploring the Role of Social Connection in Interventions With Military Veterans Diagnosed With Post-traumatic Stress Disorder: Systematic Narrative Review
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Richard D. Gettings, Jenna Kirtley, Gemma Wilson-Menzfeld, Gavin E. Oxburgh, Derek Farrell, and Matthew D. Kiernan
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loneliness ,mental health ,military ,Post-Traumatic Stress Disorder ,psychosocial ,social isolation ,Psychology ,BF1-990 - Abstract
BackgroundIt has been identified that military veterans have distinct experiences of loneliness and social isolation and, when comparing this community to other client groups with a PTSD diagnosis, veterans respond less favorably to treatment. However, the link between PTSD and loneliness for veterans remains insufficiently researched and it is unclear if there are effective interventions tackling this distinct experience of loneliness.AimsThis systematic narrative review aimed to synthesize existing evidence incorporating elements of social connection, social isolation, and loneliness within interventions for military veterans with a diagnosis of PTSD, consequently aiming to examine the impact of such interventions upon this community.MethodsSix databases were searched, utilizing relevant search criteria, with no date restrictions. Articles were included if they involved intervention or treatment for military veterans with PTSD and considered elements of social connection, social isolation, and/or loneliness. The initial search returned 202 papers. After exclusions, removal of duplications, and a reference/citation search, 28 papers remained and were included in this review.ResultsFrom the 28 studies, 11 directly addressed social isolation and two studies directly addressed loneliness. Six themes were generated: (i) rethinking the diagnosis of PTSD, (ii) holistic interventions, (iii) peer support, (iv) social reintegration, (v) empowerment through purpose and community, and (vi) building trust.ConclusionsA direct focus upon social reintegration and engagement, psychosocial functioning, building trust, peer support, group cohesiveness and empowerment through a sense of purpose and learning new skills may mitigate experiential loneliness and social isolation for veterans with PTSD. Future research and practice should further explore the needs of the PTSD-diagnosed veteran community, seek to explore and identify potential common routes toward the development of PTSD within this community and consider bespoke interventions for tackling loneliness.
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- 2022
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14. Liver-lung axes in alcohol-related liver disease
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Gavin E. Arteel
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liver diseases ,alcoholic liver disease ,acute lung injury ,respiratory distress syndrome, adult ,Diseases of the digestive system. Gastroenterology ,RC799-869 - Abstract
Alcohol-related liver disease (ALD) and alcohol-related susceptibility to acute lung injury are the leading causes of morbidity and mortality due to chronic alcohol abuse. Most commonly, alcohol-induced injury to both organs are evaluated independently, although they share many parallel mechanisms of injury. Moreover, recent studies indicate that there is a potential liver lung axis that may contribute to organ pathology. This mini-review explores established and potential mechanisms of organ-organ crosstalk in ALD and alcohol-related lung injury.
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- 2020
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15. Lipid composition and abundance in the reproductive and alimentary tracts of female Haemonchus contortus
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Tao Wang, Guangxu Ma, Shuai Nie, Nicholas A. Williamson, Gavin E. Reid, and Robin B. Gasser
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Haemonchus contortus ,Reproductive tract ,Gut ,Parasitic nematode ,Lipidome ,Lipids ,Infectious and parasitic diseases ,RC109-216 - Abstract
Abstract Background Lipids play essential structural and functional roles in the biology of animals. Studying the composition and abundance of lipids in parasites should assist in gaining a better understanding of their molecular biology, biochemistry and host-parasite interactions. Methods Here, we used a combination of high-performance liquid chromatography and mass spectrometric analyses, combined with bioinformatics, to explore the lipid composition and abundance in the reproductive (Rt) and alimentary (At) tracts of Haemonchus contortus. Results We identified and quantified 320 unique lipid species representing four categories: glycerolipids, glycerophospholipids, sphingolipids and steroid lipids. Glycerolipids (i.e. triradylglycerols) and glycerophospholipids (i.e. glycerophosphocholines) were the most commonly and abundant lipid classes identified and were significantly enriched in Rt and At, respectively. We propose that select parasite-derived lipids in Rt and At of adult female H. contortus are required as an energy source (i.e. triradylglycerol) or are involved in phospholipid biosynthesis (i.e. incorporated fatty acids) and host-parasite interactions (i.e. phospholipids and lysophospholipids). Conclusions This work provides a first foundation to explore lipids at the organ-specific and tissue-specific levels in nematodes, and to start to unravel aspects of lipid transport, synthesis and metabolism, with a perspective on discovering new intervention targets.
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- 2020
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16. Acetylator Genotype-Dependent Dyslipidemia in Rats Congenic for N-Acetyltransferase 2
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Kyung U. Hong, Mark A. Doll, Angeliki Lykoudi, Raúl A. Salazar-González, Mariam R. Habil, Kennedy M. Walls, Alaa F. Bakr, Smita S. Ghare, Shirish S. Barve, Gavin E. Arteel, and David W. Hein
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Arylamine N-acetyltransferase ,obesity ,insulin resistance ,metabolic syndrome ,diet ,dyslipidemia ,Toxicology. Poisons ,RA1190-1270 - Abstract
Recent reports suggest that arylamine N-acetyltransferases (NAT1 and/or NAT2) serve important roles in regulation of energy utility and insulin sensitivity. We investigated the interaction between diet (control vs. high-fat diet) and acetylator phenotype (rapid vs. slow) using previously established congenic rat lines (in F344 background) that exhibit rapid or slow Nat2 (orthologous to human NAT1) acetylator genotypes. Male and female rats of each genotype were fed control or high-fat (Western-style) diet for 26 weeks. We then examined diet- and acetylator genotype-dependent changes in body and liver weights, systemic glucose tolerance, insulin sensitivity, and plasma lipid profile. Male and female rats on the high fat diet weighed approximately 10% more than rats on the control diet and the percentage liver to body weight was consistently higher in rapid than slow acetylator rats. Rapid acetylator rats were more prone to develop dyslipidemia overall (i.e., higher triglyceride; higher LDL; and lower HDL), compared to slow acetylator rats. Total cholesterol (TC)-to-HDL ratios were significantly higher and HDL-to-LDL ratios were significantly lower in rapid acetylator rats. Our data suggest that rats with rapid systemic Nat2 (NAT1 in humans) genotype exhibited higher dyslipidemia conferring risk for metabolic syndrome and cardiovascular dysfunction.
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- 2020
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17. A Non-canonical Pathway with Potential for Safer Modulation of Transforming Growth Factor-β1 in Steroid-Resistant Airway Diseases
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Meina Li, Christine R. Keenan, Guillermo Lopez-Campos, Jonathan E. Mangum, Qianyu Chen, Danica Prodanovic, Yuxiu C. Xia, Shenna Y. Langenbach, Trudi Harris, Vinzenz Hofferek, Gavin E. Reid, and Alastair G. Stewart
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Science - Abstract
Summary: Impaired therapeutic responses to anti-inflammatory glucocorticoids (GC) in chronic respiratory diseases are partly attributable to interleukins and transforming growth factor β1 (TGF-β1). However, previous efforts to prevent induction of GC insensitivity by targeting established canonical and non-canonical TGF-β1 pathways have been unsuccessful. Here we elucidate a TGF-β1 signaling pathway modulating GC activity that involves LIM domain kinase 2-mediated phosphorylation of cofilin1. Severe, steroid-resistant asthmatic airway epithelium showed increased levels of immunoreactive phospho-cofilin1. Phospho-cofilin1 was implicated in the activation of phospholipase D (PLD) to generate the effector(s) (lyso)phosphatidic acid, which mimics the TGF-β1-induced GC insensitivity. TGF-β1 induction of the nuclear hormone receptor corepressor, SMRT (NCOR2), was dependent on cofilin1 and PLD activities. Depletion of SMRT prevented GC insensitivity. This pathway for GC insensitivity offers several promising drug targets that potentially enable a safer approach to the modulation of TGF-β1 in chronic inflammatory diseases than is afforded by global TGF-β1 inhibition. : Biological Sciences; Biochemistry; Molecular Biology; Cell Biology Subject Areas: Biological Sciences, Biochemistry, Molecular Biology, Cell Biology
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- 2019
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18. Comparative bioinformatic analysis suggests that specific dauer-like signalling pathway components regulate Toxocara canis development and migration in the mammalian host
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Guangxu Ma, Tao Wang, Pasi K. Korhonen, Shuai Nie, Gavin E. Reid, Andreas J. Stroehlein, Anson V. Koehler, Bill C. H. Chang, Andreas Hofmann, Neil D. Young, and Robin B. Gasser
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Toxocara canis ,Ascaris suum ,Dauer signalling pathway ,Dafachronic acid ,Arrested development ,Infectious and parasitic diseases ,RC109-216 - Abstract
Abstract Background Toxocara canis is quite closely related to Ascaris suum but its biology is more complex, involving a phase of arrested development (diapause or hypobiosis) in tissues as well as transplacental and transmammary transmission routes. In the present study, we explored and compared dauer-like signalling pathways of T. canis and A. suum to infer which components in these pathways might associate with, or regulate, this added complexity in T. canis. Methods Guided by information for Caenorhabditis elegans, we bioinformatically inferred and compared components of dauer-like signalling pathways in T. canis and A. suum using genomic and transcriptomic data sets. In these two ascaridoids, we also explored endogenous dafachronic acids (DAs), which are known to be critical in regulating larval developmental processes in C. elegans and other nematodes, by liquid chromatography-mass spectrometry (LC-MS). Results Orthologues of C. elegans dauer signalling genes were identified in T. canis (n = 55) and A. suum (n = 51), inferring the presence of a dauer-like signalling pathway in both species. Comparisons showed clear differences between C. elegans and these ascaridoids as well as between T. canis and A. suum, particularly in the transforming growth factor-β (TGF-β) and insulin-like signalling pathways. Specifically, in both A. suum and T. canis, there was a paucity of genes encoding SMAD transcription factor-related protein (daf-3, daf-5, daf-8 and daf-14) and insulin/insulin-like peptide (daf-28, ins-4, ins-6 and ins-7) homologues, suggesting an evolution and adaptation of the signalling pathway in these parasites. In T. canis, there were more orthologues coding for homologues of antagonist insulin-like peptides (Tc-ins-1 and Tc-ins-18), an insulin receptor substrate (Tc-ist-1) and a serine/threonine kinase (Tc-akt-1) than in A. suum, suggesting potentiated functional roles for these molecules in regulating larval diapause and reactivation. A relatively conserved machinery was proposed for DA synthesis in the two ascaridoids, and endogenous Δ4- and Δ7-DAs were detected in them by LC-MS analysis. Differential transcription analysis between T. canis and A. suum suggests that ins-17 and ins-18 homologues are specifically involved in regulating development and migration in T. canis larvae in host tissues. Conclusion The findings of this study provide a basis for functional explorations of insulin-like peptides, signalling hormones (i.e. DAs) and related nuclear receptors, proposed to link to development and/or parasite-host interactions in T. canis. Elucidating the functional roles of these molecules might contribute to the discovery of novel anthelmintic targets in ascaridoids.
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- 2019
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19. Characterization of brain‐derived extracellular vesicle lipids in Alzheimer's disease
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Huaqi Su, Yepy H. Rustam, Colin L. Masters, Enes Makalic, Catriona A. McLean, Andrew F. Hill, Kevin J. Barnham, Gavin E. Reid, and Laura J. Vella
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Alzheimer's disease ,brain ,exosomes ,extracellular vesicles ,frontal cortex ,glycerophospholipids ,Cytology ,QH573-671 - Abstract
Abstract Lipid dyshomeostasis is associated with the most common form of dementia, Alzheimer's disease (AD). Substantial progress has been made in identifying positron emission tomography and cerebrospinal fluid biomarkers for AD, but they have limited use as front‐line diagnostic tools. Extracellular vesicles (EVs) are released by all cells and contain a subset of their parental cell composition, including lipids. EVs are released from the brain into the periphery, providing a potential source of tissue and disease specific lipid biomarkers. However, the EV lipidome of the central nervous system is currently unknown and the potential of brain‐derived EVs (BDEVs) to inform on lipid dyshomeostasis in AD remains unclear. The aim of this study was to reveal the lipid composition of BDEVs in human frontal cortex, and to determine whether BDEVs have an altered lipid profile in AD. Using semi‐quantitative mass spectrometry, we describe the BDEV lipidome, covering four lipid categories, 17 lipid classes and 692 lipid molecules. BDEVs were enriched in glycerophosphoserine (PS) lipids, a characteristic of small EVs. Here we further report that BDEVs are enriched in ether‐containing PS lipids, a finding that further establishes ether lipids as a feature of EVs. BDEVs in the AD frontal cortex offered improved detection of dysregulated lipids in AD over global lipid profiling of this brain region. AD BDEVs had significantly altered glycerophospholipid and sphingolipid levels, specifically increased plasmalogen glycerophosphoethanolamine and decreased polyunsaturated fatty acyl containing lipids, and altered amide‐linked acyl chain content in sphingomyelin and ceramide lipids relative to CTL. The most prominent alteration was a two‐fold decrease in lipid species containing anti‐inflammatory/pro‐resolving docosahexaenoic acid. The in‐depth lipidome analysis provided in this study highlights the advantage of EVs over more complex tissues for improved detection of dysregulated lipids that may serve as potential biomarkers in the periphery.
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- 2021
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20. Sexual Mismatch Between Vessel-Associated Foraging and Discard Consumption in a Marine Top Predator
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Joan Giménez, Gavin E. Arneill, Ashley Bennison, Enrico Pirotta, Hans D. Gerritsen, Thomas W. Bodey, Stuart Bearhop, Keith C. Hamer, Stephen Votier, and Mark Jessopp
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diet ,fisheries ,northern gannets ,stable isotopes ,tracking data ,Science ,General. Including nature conservation, geographical distribution ,QH1-199.5 - Abstract
Sex differences in diet and foraging behaviour are common in sexually dimorphic species, often driven by differences in the cost of locomotion or ability to exploit different ecological niches. However, sex-specific foraging strategies also occur in monomorphic or slightly dimorphic species where the drivers are poorly understood. Here, we study sex differences in foraging of northern gannets (Morus bassanus), where females are only slightly heavier than males. Using concurrently tracked gannets (298 full foraging trips from 81 individuals) and fishing vessels across 5 years, we quantify individual-based vessel-associated putative foraging, and relate this to discard consumption. We found a significant positive relationship between time spent in vessel-associated foraging and discard consumption for both sexes. However, while females showed greater proportions of vessel-associated foraging than males, discarded fish contributed less to the diet of females in all years. These results contrast with previous suggestions that female gannets interact with vessels less often than males, and are consistent with competitive exclusion of females from trawler-associated discards. Our findings give insight into sexual differences in foraging behaviour in the absence of dimorphism that are necessary to predict their response to environmental and anthropogenic changes.
- Published
- 2021
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21. Helminth lipidomics: Technical aspects and future prospects
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Tao Wang, Shuai Nie, Gavin E. Reid, and Robin B. Gasser
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Lipid (fat) ,Lipidome ,Lipidomics ,Mass spectrometry ,Parasitic worm ,Helminth ,Infectious and parasitic diseases ,RC109-216 - Abstract
Lipidomics is a relatively recent molecular research field, and explores lipids (fats) and their biology using advanced mass spectrometry technologies. Although this field has expanded significantly in biomedical and biotechnological disciplines, it is still in its infancy in molecular parasitology. Our goal here is to review and discuss technical aspects of MS-based lipidomics and its recent applications to parasitic worms, as well as challenges and future directions for worm lipid research. In a multi-omic paradigm, we expect that the exploration of lipidomic data for parasitic worms will yield important insights into lipid-associated biological pathways and processes, including the regulation of essential signalling pathways, parasite invasion, establishment, adaptation and development.
- Published
- 2021
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22. Rifaximin prophylaxis causes resistance to the last-resort antibiotic daptomycin
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Turner, Adrianna M., Li, Lucy, Monk, Ian R., Lee, Jean Y. H., Ingle, Danielle J., Portelli, Stephanie, Sherry, Norelle L., Isles, Nicole, Seemann, Torsten, Sharkey, Liam K., Walsh, Calum J., Reid, Gavin E., Nie, Shuai, Eijkelkamp, Bart A., Holmes, Natasha E., Collis, Brennan, Vogrin, Sara, Hiergeist, Andreas, Weber, Daniela, Gessner, Andre, Holler, Ernst, Ascher, David B., Duchene, Sebastian, Scott, Nichollas E., Stinear, Timothy P., Kwong, Jason C., Gorrie, Claire L., Howden, Benjamin P., and Carter, Glen P.
- Published
- 2024
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23. Quantitative lipidomic analysis of Ascaris suum.
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Tao Wang, Shuai Nie, Guangxu Ma, Johnny Vlaminck, Peter Geldhof, Nicholas A Williamson, Gavin E Reid, and Robin B Gasser
- Subjects
Arctic medicine. Tropical medicine ,RC955-962 ,Public aspects of medicine ,RA1-1270 - Abstract
Ascaris is a soil-transmitted nematode that causes ascariasis, a neglected tropical disease affecting predominantly children and adolescents in the tropics and subtropics. Approximately 0.8 billion people are affected worldwide, equating to 0.86 million disability-adjusted life-years (DALYs). Exploring the molecular biology of Ascaris is important to gain a better understanding of the host-parasite interactions and disease processes, and supports the development of novel interventions. Although advances have been made in the genomics, transcriptomics and proteomics of Ascaris, its lipidome has received very limited attention. Lipidomics is an important sub-discipline of systems biology, focused on exploring lipids profiles in tissues and cells, and elucidating their biological and metabolic roles. Here, we characterised the lipidomes of key developmental stages and organ systems of Ascaris of porcine origin via high throughput LC-MS/MS. In total, > 500 lipid species belonging to 18 lipid classes within three lipid categories were identified and quantified-in precise molar amounts in relation to the dry weight of worm material-in different developmental stages/sexes and organ systems. The results showed substantial differences in the composition and abundance of lipids with key roles in cellular processes and functions (e.g. energy storage regulation and membrane structure) among distinct stages and among organ systems, likely reflecting differing demands for lipids, depending on stage of growth and development as well as the need to adapt to constantly changing environments within and outside of the host animal. This work provides the first step toward understanding the biology of lipids in Ascaris, with possibilities to work toward designing new interventions against ascariasis.
- Published
- 2020
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24. Type IX Secretion System Cargo Proteins Are Glycosylated at the C Terminus with a Novel Linking Sugar of the Wbp/Vim Pathway
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Paul D. Veith, Mikio Shoji, Richard A. J. O’Hair, Michael G. Leeming, Shuai Nie, Michelle D. Glew, Gavin E. Reid, Koji Nakayama, and Eric C. Reynolds
- Subjects
Porphyromonas gingivalis ,Tannerella forsythia ,glycoprotein ,type IX secretion system ,lipopolysaccharide ,Microbiology ,QR1-502 - Abstract
ABSTRACT Porphyromonas gingivalis and Tannerella forsythia use the type IX secretion system to secrete cargo proteins to the cell surface where they are anchored via glycolipids. In P. gingivalis, the glycolipid is anionic lipopolysaccharide (A-LPS), of partially known structure. Modified cargo proteins were deglycosylated using trifluoromethanesulfonic acid and digested with trypsin or proteinase K. The residual modifications were then extensively analyzed by tandem mass spectrometry. The C terminus of each cargo protein was amide-bonded to a linking sugar whose structure was deduced to be 2-N-seryl, 3-N-acetylglucuronamide in P. gingivalis and 2-N-glycyl, 3-N-acetylmannuronic acid in T. forsythia. The structures indicated the involvement of the Wbp pathway to produce 2,3-di-N-acetylglucuronic acid and a WbpS amidotransferase to produce the uronamide form of this sugar in P. gingivalis. The wbpS gene was identified as PGN_1234 as its deletion resulted in the inability to produce the uronamide. In addition, the P. gingivalis vimA mutant which lacks A-LPS was successfully complemented by the T. forsythia vimA gene; however, the linking sugar was altered to include glycine rather than serine. After removal of the acetyl group at C-2 by the putative deacetylase, VimE, VimA presumably transfers the amino acid to complete the biosynthesis. The data explain all the enzyme activities required for the biosynthesis of the linking sugar accounting for six A-LPS-specific genes. The linking sugar is therefore the key compound that enables the attachment of cargo proteins in P. gingivalis and T. forsythia. We propose to designate this novel linking sugar biosynthetic pathway the Wbp/Vim pathway. IMPORTANCE Porphyromonas gingivalis and Tannerella forsythia, two pathogens associated with severe gum disease, use the type IX secretion system (T9SS) to secrete and attach toxic arrays of virulence factor proteins to their cell surfaces. The proteins are tethered to the outer membrane via glycolipid anchors that have remained unidentified for more than 2 decades. In this study, the first sugar molecules (linking sugars) in these anchors are identified and found to be novel compounds. The novel biosynthetic pathway of these linking sugars is also elucidated. A diverse range of bacteria that do not have the T9SS were found to have the genes for this pathway, suggesting that they may synthesize similar linking sugars for utilization in different systems. Since the cell surface attachment of virulence factors is essential for virulence, these findings reveal new targets for the development of novel therapies.
- Published
- 2020
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25. The liver matrisome – looking beyond collagensKey points
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Gavin E. Arteel and Alexandra Naba
- Subjects
Extracellular matrix ,ECM ,Proteomics ,Liver disease ,Fibrosis ,Regeneration ,Diseases of the digestive system. Gastroenterology ,RC799-869 - Abstract
Summary: The extracellular matrix (ECM) is a diverse microenvironment that maintains bidirectional communication with surrounding cells to regulate cell and tissue homeostasis. The classical definition of the ECM has more recently been extended to include non-fibrillar proteins that either interact or are structurally affiliated with the ECM, termed the ‘matrisome.’ In addition to providing the structure and architectural support for cells and tissue, the matrisome serves as a reservoir for growth factors and cytokines, as well as a signaling hub via which cells can communicate with their environment and vice-versa. The matrisome is a master regulator of tissue homeostasis and organ function, which can dynamically and appropriately respond to any stress or injury. Failure to properly regulate these responses can lead to changes in the matrisome that are maladaptive. Hepatic fibrosis is a canonical example of ECM dyshomeostasis, leading to accumulation of predominantly collagenous ECM; indeed, hepatic fibrosis is considered almost synonymous with collagen accumulation. However, the qualitative and quantitative alterations of the hepatic matrisome during fibrosis are much more diverse than simple accumulation of collagens and occur long before fibrosis is histologically detected. A deeper understanding of the hepatic matrisome and its response to injury could yield new mechanistic insights into disease progression and regression, as well as potentially identify new biomarkers for both. In this review, we discuss the role of the ECM in liver diseases and look at new “omic” approaches to study this compartment.
- Published
- 2020
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26. Misjudging early embryo mortality in natural human reproduction [version 1; peer review: 2 approved]
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Gavin E. Jarvis
- Subjects
Medicine ,Science - Abstract
In 2002, in a judgment relating to the use of the morning-after pill, Mr Justice Munby held that pregnancy begins with the implantation of an embryo into the uterus of a woman. The case involved a large body of expert witness evidence including medical and physiological details of human reproduction. Munby J. emphasised one particular aspect of this evidence: namely, the developmental failure rate of human embryos after fertilisation. Under natural conditions, embryo loss is approximately 10-40% before implantation, and total loss from fertilisation to birth is 40-60% (Jarvis, 2016). By contrast, and based on expert witness testimony, Munby J. stated that not much more than 25% of successfully fertilised eggs reach the implantation stage, and that fewer than 15% of fertilised eggs result in a birth, figures that do not accurately represent scientific knowledge regarding human embryo mortality and pregnancy loss under natural conditions. Rather, these figures were derived from experimental laboratory data and clinical outcomes from in vitro fertilisation treatment. Testimony provided by other expert witnesses directly contradicted these specific numerical claims. In emphasising these figures, Munby J. gave the impression that human embryo mortality is substantially higher than available scientific evidence indicated. In this critique, all the scientific expert witness evidence is presented and reviewed, and an explanation provided for why the emphasised figures are wrong. Whether there are implications of Munby J.’s scientific misjudgment on the legal outcome is for others to consider.
- Published
- 2020
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27. Immiscible inclusion bodies formed by polyglutamine and poly(glycine-alanine) are enriched with distinct proteomes but converge in proteins that are risk factors for disease and involved in protein degradation.
- Author
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Mona Radwan, Jordan D Lilley, Ching-Seng Ang, Gavin E Reid, and Danny M Hatters
- Subjects
Medicine ,Science - Abstract
Poly(glycine-alanine) (polyGA) is one of the polydipeptides expressed in Frontotemporal Dementia and/or Amyotrophic Lateral Sclerosis 1 caused by C9ORF72 mutations and accumulates as inclusion bodies in the brain of patients. Superficially these inclusions are similar to those formed by polyglutamine (polyQ)-expanded Huntingtin exon 1 (Httex1) in Huntington's disease. Both have been reported to form an amyloid-like structure suggesting they might aggregate via similar mechanisms and therefore recruit the same repertoire of endogenous proteins. When co-expressed in the same cell, polyGA101 and Httex1(Q97) inclusions adopted immiscible phases suggesting different endogenous proteins would be enriched. Proteomic analyses identified 822 proteins in the inclusions. Only 7 were specific to polyGA and 4 specific to Httex1(Q97). Quantitation demonstrated distinct enrichment patterns for the proteins not specific to each inclusion type (up to ~8-fold normalized to total mass). The proteasome, microtubules, TriC chaperones, and translational machinery were enriched in polyGA aggregates, whereas Dnaj chaperones, nuclear envelope and RNA splicing proteins were enriched in Httex1(Q97) aggregates. Both structures revealed a collection of folding and degradation machinery including proteins in the Httex1(Q97) aggregates that are risk factors for other neurodegenerative diseases involving protein aggregation when mutated, which suggests a convergence point in the pathomechanisms of these diseases.
- Published
- 2020
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28. Multi-Omic Analysis to Characterize Metabolic Adaptation of the E. coli Lipidome in Response to Environmental Stress
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Thomas Kralj, Madison Nuske, Vinzenz Hofferek, Marc-Antoine Sani, Tzong-Hsien Lee, Frances Separovic, Marie-Isabel Aguilar, and Gavin E. Reid
- Subjects
E. coli ,lipidome ,proteome ,environmental stress ,mass spectrometry ,ion mobility ,Microbiology ,QR1-502 - Abstract
As an adaptive survival response to exogenous stress, bacteria undergo dynamic remodelling of their lipid metabolism pathways to alter the composition of their cellular membranes. Here, using Escherichia coli as a well characterised model system, we report the development and application of a ‘multi-omics’ strategy for comprehensive quantitative analysis of the temporal changes in the lipidome and proteome profiles that occur under exponential growth phase versus stationary growth phase conditions i.e., nutrient depletion stress. Lipidome analysis performed using ‘shotgun’ direct infusion-based ultra-high resolution accurate mass spectrometry revealed a quantitative decrease in total lipid content under stationary growth phase conditions, along with a significant increase in the mol% composition of total cardiolipin, and an increase in ‘odd-numbered’ acyl-chain length containing glycerophospholipids. The inclusion of field asymmetry ion mobility spectrometry was shown to enable the enrichment and improved depth of coverage of low-abundance cardiolipins, while ultraviolet photodissociation-tandem mass spectrometry facilitated more complete lipid structural characterisation compared with conventional collision-induced dissociation, including unambiguous assignment of the odd-numbered acyl-chains as containing cyclopropyl modifications. Proteome analysis using data-dependent acquisition nano-liquid chromatography mass spectrometry and tandem mass spectrometry analysis identified 83% of the predicted E. coli lipid metabolism enzymes, which enabled the temporal dependence associated with the expression of key enzymes responsible for the observed adaptive lipid metabolism to be determined, including those involved in phospholipid metabolism (e.g., ClsB and Cfa), fatty acid synthesis (e.g., FabH) and degradation (e.g., FadA/B,D,E,I,J and M), and proteins involved in the oxidative stress response resulting from the generation of reactive oxygen species during β-oxidation or lipid degradation.
- Published
- 2022
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29. Differential composition of DHA and very-long-chain PUFAs in rod and cone photoreceptors
- Author
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Martin-Paul Agbaga, Dana K. Merriman, Richard S. Brush, Todd A. Lydic, Shannon M. Conley, Muna I. Naash, Shelley Jackson, Amina S. Woods, Gavin E. Reid, Julia V. Busik, and Robert E. Anderson
- Subjects
rod- and cone-dominant retinas ,supraenoic lipids ,glycerophospholipids ,macular degeneration ,polyunsaturated fatty acids ,docosahexaenoic acid ,Biochemistry ,QD415-436 - Abstract
Long-chain PUFAs (LC-PUFAs; C20–C22; e.g., DHA and arachidonic acid) are highly enriched in vertebrate retina, where they are elongated to very-long-chain PUFAs (VLC-PUFAs; C ≥28) by the elongation of very-long-chain fatty acids-4 (ELOVL4) enzyme. These fatty acids play essential roles in modulating neuronal function and health. The relevance of different lipid requirements in rods and cones to disease processes, such as age-related macular degeneration, however, remains unclear. To better understand the role of LC-PUFAs and VLC-PUFAs in the retina, we investigated the lipid compositions of whole retinas or photoreceptor outer segment (OS) membranes in rodents with rod- or cone-dominant retinas. We analyzed fatty acid methyl esters and the molecular species of glycerophospholipids (phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine) by GC-MS/GC-flame ionization detection and ESI-MS/MS, respectively. We found that whole retinas and OS membranes in rod-dominant animals compared with cone-dominant animals had higher amounts of LC-PUFAs and VLC-PUFAs. Compared with those of rod-dominant animals, retinas and OS membranes from cone-dominant animals also had about 2-fold lower levels of di-DHA (22:6/22:6) molecular species of glycerophospholipids. Because PUFAs are necessary for optimal G protein-coupled receptor signaling in rods, these findings suggest that cones may not have the same lipid requirements as rods.
- Published
- 2018
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30. Scalable and accurate deep learning with electronic health records
- Author
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Alvin Rajkomar, Eyal Oren, Kai Chen, Andrew M. Dai, Nissan Hajaj, Michaela Hardt, Peter J. Liu, Xiaobing Liu, Jake Marcus, Mimi Sun, Patrik Sundberg, Hector Yee, Kun Zhang, Yi Zhang, Gerardo Flores, Gavin E. Duggan, Jamie Irvine, Quoc Le, Kurt Litsch, Alexander Mossin, Justin Tansuwan, De Wang, James Wexler, Jimbo Wilson, Dana Ludwig, Samuel L. Volchenboum, Katherine Chou, Michael Pearson, Srinivasan Madabushi, Nigam H. Shah, Atul J. Butte, Michael D. Howell, Claire Cui, Greg S. Corrado, and Jeffrey Dean
- Subjects
Computer applications to medicine. Medical informatics ,R858-859.7 - Abstract
Artificial intelligence: Algorithm predicts clinical outcomes for hospital inpatients Artificial intelligence outperforms traditional statistical models at predicting a range of clinical outcomes from a patient’s entire raw electronic health record (EHR). A team led by Alvin Rajkomar and Eyal Oren from Google in Mountain View, California, USA, developed a data processing pipeline for transforming EHR files into a standardized format. They then applied deep learning models to data from 216,221 adult patients hospitalized for at least 24 h each at two academic medical centers, and showed that their algorithm could accurately predict risk of mortality, hospital readmission, prolonged hospital stay and discharge diagnosis. In all cases, the method proved more accurate than previously published models. The authors provide a case study to serve as a proof-of-concept of how such an algorithm could be used in routine clinical practice in the future.
- Published
- 2018
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31. Citalopram inhibits platelet function independently of SERT-mediated 5-HT transport
- Author
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Harvey G. Roweth, Ruoling Yan, Nader H. Bedwani, Alisha Chauhan, Nicole Fowler, Alice H. Watson, Jean-Daniel Malcor, Stewart O. Sage, and Gavin E. Jarvis
- Subjects
Medicine ,Science - Abstract
Abstract Citalopram prevents serotonin (5-HT) uptake into platelets by blocking the serotonin reuptake transporter (SERT). Although some clinical data suggest that selective serotonin reuptake inhibitors (SSRIs) may affect haemostasis and thrombosis, these poorly-characterised effects are not well understood mechanistically and useful in vitro data is limited. We sought to determine whether the inhibitory effects of citalopram on platelets are mediated via its pharmacological inhibition of 5-HT transport. We quantified the inhibitory potency of (RS)-, (R)- and (S)-citalopram on platelet function. If SERT blockade is the primary mechanism for citalopram-mediated platelet inhibition, these potencies should show quantitative congruence with inhibition of 5-HT uptake. Our data show that citalopram inhibits platelet aggregation, adhesion and thromboxane production with no difference in potency between (R)- and (S)-isomers. By contrast, citalopram had a eudysmic ratio of approximately 17 (S > R) for SERT blockade. Furthermore, nanomolar concentrations of citalopram inhibited 5-HT uptake into platelets but had no effect on other platelet functions, which were inhibited by micromolar concentrations. Our data indicate that citalopram-induced inhibition of platelets in vitro is not mediated by blockade of 5-HT transport. This raises a new question for future investigation: by what mechanism(s) does citalopram inhibit platelets?
- Published
- 2018
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32. A biosensor-based framework to measure latent proteostasis capacity
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Rebecca J. Wood, Angelique R. Ormsby, Mona Radwan, Dezerae Cox, Abhishek Sharma, Tobias Vöpel, Simon Ebbinghaus, Mikael Oliveberg, Gavin E. Reid, Alex Dickson, and Danny M. Hatters
- Subjects
Science - Abstract
A pool of quality control proteins (QC) maintains the protein-folding homeostasis in the cell, but its quantitative analysis is challenging. Here the authors develop a FRET sensor based on the protein barnase, able to quantify QC holdase activity and its ability to suppress protein aggregation.
- Published
- 2018
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33. Proceedings of the 16th Annual UT-KBRIN Bioinformatics Summit 2016: proceedings
- Author
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L. Leon Dent, Sammed N. Mandape, Siddharth Pratap, Jianan Dong, Jamaine Davis, Jennifer A. Gaddy, Kofi Amoah, Steve Damo, Dana R. Marshall, Jacob Jones, Toni Brandt, Gilberto Diaz, Qingguo Wang, Todd Gary, Ashwini Yenamandra, Marina Z. Ghattas, Marwa Elrakaiby, Ramy K. Aziz, Hamdallah H. Zedan, Moamen Elmassry, Marwa ElRakaiby, Mariam Lotfy, Jarrad Marcel, Rania A. Khattab, Maha M. Abdelfattah, Jack A. Gilbert, Pouya Dini, Shavahn C. Loux, Kirsten E. Scoggin, Alejandro Esteller-Vico, Edward L. Squires, Mats H. T. Troedsson, Peter Daels, Barry A. Ball, Kalpani De Silva, Ernest Bailey, Joel C. Stephens, Theodore S. Kalbfleisch, Christine E. Dolin, Lauren G. Poole, Daniel W. Wilkey, Eric C. Rouchka, Gavin E. Arteel, Michelle T. Barati, Michael L. Merchant, Richard M. Higashi, Teresa W-M Fan, Hunter Moseley, and Andrew N Lane
- Subjects
Medicine ,Science - Published
- 2017
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34. A thiol probe for measuring unfolded protein load and proteostasis in cells
- Author
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Moore Z. Chen, Nagaraj S. Moily, Jessica L. Bridgford, Rebecca J. Wood, Mona Radwan, Trevor A. Smith, Zhegang Song, Ben Zhong Tang, Leann Tilley, Xiaohong Xu, Gavin E. Reid, Mahmoud A. Pouladi, Yuning Hong, and Danny M. Hatters
- Subjects
Science - Abstract
Proteostasis is maintained through a number of molecular mechanisms, some of which function to protect the folded state of proteins. Here the authors demonstrate the use of TPE-MI in a fluorigenic dye assay for the quantitation of unfolded proteins that can be used to assess proteostasis on a cellular or proteome scale.
- Published
- 2017
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35. Huntingtin Inclusions Trigger Cellular Quiescence, Deactivate Apoptosis, and Lead to Delayed Necrosis
- Author
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Yasmin M. Ramdzan, Mikhail M. Trubetskov, Angelique R. Ormsby, Estella A. Newcombe, Xiaojing Sui, Mark J. Tobin, Marie N. Bongiovanni, Sally L. Gras, Grant Dewson, Jason M.L. Miller, Steven Finkbeiner, Nagaraj S. Moily, Jonathan Niclis, Clare L. Parish, Anthony W. Purcell, Michael J. Baker, Jacqueline A. Wilce, Saboora Waris, Diana Stojanovski, Till Böcking, Ching-Seng Ang, David B. Ascher, Gavin E. Reid, and Danny M. Hatters
- Subjects
Biology (General) ,QH301-705.5 - Abstract
Summary: Competing models exist in the literature for the relationship between mutant Huntingtin exon 1 (Httex1) inclusion formation and toxicity. In one, inclusions are adaptive by sequestering the proteotoxicity of soluble Httex1. In the other, inclusions compromise cellular activity as a result of proteome co-aggregation. Using a biosensor of Httex1 conformation in mammalian cell models, we discovered a mechanism that reconciles these competing models. Newly formed inclusions were composed of disordered Httex1 and ribonucleoproteins. As inclusions matured, Httex1 reconfigured into amyloid, and other glutamine-rich and prion domain-containing proteins were recruited. Soluble Httex1 caused a hyperpolarized mitochondrial membrane potential, increased reactive oxygen species, and promoted apoptosis. Inclusion formation triggered a collapsed mitochondrial potential, cellular quiescence, and deactivated apoptosis. We propose a revised model where sequestration of soluble Httex1 inclusions can remove the trigger for apoptosis but also co-aggregate other proteins, which curtails cellular metabolism and leads to a slow death by necrosis. : Httex1 aggregation into inclusions has paradoxically been reported as either toxic or beneficial in Huntington’s disease. Ramdzan et al. define a dual mechanism of toxicity that explains this paradox. Soluble Httex1 triggers a fast death by apoptosis, whereas Httex1 inclusions invoke quiescence and redirect death to a slower necrotic pathway. Keywords: Huntington’s disease, flow cytometry, ribosome quality control, stress granule, RNA granule, P bodies, translation
- Published
- 2017
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36. Dafachronic acid promotes larval development in Haemonchus contortus by modulating dauer signalling and lipid metabolism.
- Author
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Guangxu Ma, Tao Wang, Pasi K Korhonen, Neil D Young, Shuai Nie, Ching-Seng Ang, Nicholas A Williamson, Gavin E Reid, and Robin B Gasser
- Subjects
Immunologic diseases. Allergy ,RC581-607 ,Biology (General) ,QH301-705.5 - Abstract
Here, we discovered an endogenous dafachronic acid (DA) in the socioeconomically important parasitic nematode Haemonchus contortus. We demonstrate that DA promotes larval exsheathment and development in this nematode via a relatively conserved nuclear hormone receptor (DAF-12). This stimulatory effect is dose- and time-dependent, and relates to a modulation of dauer-like signalling, and glycerolipid and glycerophospholipid metabolism, likely via a negative feedback loop. Specific chemical inhibition of DAF-9 (cytochrome P450) was shown to significantly reduce the amount of endogenous DA in H. contortus; compromise both larval exsheathment and development in vitro; and modulate lipid metabolism. Taken together, this evidence shows that DA plays a key functional role in the developmental transition from the free-living to the parasitic stage of H. contortus by modulating the dauer-like signalling pathway and lipid metabolism. Understanding the intricacies of the DA-DAF-12 system and associated networks in H. contortus and related parasitic nematodes could pave the way to new, nematode-specific treatments.
- Published
- 2019
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37. Electrophilic nitro-oleic acid reverses obesity-induced hepatic steatosis
- Author
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Nicholas K.H. Khoo, Marco Fazzari, Dionysios V. Chartoumpekis, Lihua Li, Danielle Aparecida Guimaraes, Gavin E. Arteel, Sruti Shiva, and Bruce A. Freeman
- Subjects
Medicine (General) ,R5-920 ,Biology (General) ,QH301-705.5 - Abstract
Non-alcoholic fatty liver disease (NAFLD) is linked to obesity and insulin resistance and is the most prevalent chronic liver disease. During the development of obesity and NAFLD, mitochondria adapt to the increased lipid load in hepatocytes by increasing the rate of fatty acid oxidation. In concert with this, reactive species (RS) generation is increased, damaging hepatocytes and inducing inflammation. Hepatic mitochondrial dysfunction is central to the pathogenesis of NAFLD via undefined mechanisms. There are no FDA approved treatments for NAFLD other than weight loss and management of glucose tolerance. Electrophilic nitro-oleic acid (NO2-OA) displays anti-inflammatory and antioxidant signaling actions, thus mitochondrial dysfunction, RS production and inflammatory responses to NO2-OA and the insulin sensitizer rosiglitazone were evaluated in a murine model of insulin resistance and NAFLD. Mice on HFD for 20 wk displayed increased adiposity, insulin resistance and hepatic lipid accumulation (steatosis) compared to mice on normal chow (NC). The HFD mice had mitochondrial dysfunction characterized by lower hepatic mitochondrial complex I, IV and V activity compared to mice on NC. Treatment with NO2-OA or rosiglitazone for the last 42 days (out of 20 wk) abrogated HFD-mediated decreases in hepatic mitochondrial complex I, IV and V activity. Notably, NO2-OA treatment normalized hepatic triglyceride levels and significantly reversed hepatic steatosis. Despite the improved glucose tolerance observed upon rosiglitazone treatment, liver weight and hepatic triglycerides were significantly increased over vehicle-treated HFD mice. These observations support that the pleiotropic signaling actions of electrophilic fatty acids limit the complex hepatic and systemic pathogenic responses instigated by obesity, without the adverse effects of thiazolidinedione drugs such as rosiglitazone.
- Published
- 2019
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38. Sampling strategies for species with high breeding-site fidelity: A case study in burrow-nesting seabirds.
- Author
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Gavin E Arneill, Christopher M Perrins, Matt J Wood, David Murphy, Luca Pisani, Mark J Jessopp, and John L Quinn
- Subjects
Medicine ,Science - Abstract
Sampling approaches used to census and monitor populations of flora and fauna are diverse, ranging from simple random sampling to complex hierarchal stratified designs. Usually the approach taken is determined by the spatial and temporal distribution of the study population, along with other characteristics of the focal species. Long-term monitoring programs used to assess seabird population trends are facilitated by their high site fidelity, but are often hampered by large and difficult to access colonies, with highly variable densities that require intensive survey. We aimed to determine the sampling effort required to (a) estimate population size with a high degree of confidence, and (b) detect different scenarios of population change in a regionally important species in the Atlantic, the Manx shearwater (Puffinus puffinus). Analyses were carried out using data collected from tape-playback surveys on four islands in the North Atlantic. To explore how sampling effort influenced confidence around abundance estimates, we used the heuristic approach of imagining the areas sampled represented the total population, and bootstrapped varying proportions of subsamples. This revealed that abundance estimates vary dramatically when less than half of all plots (n dependent on the size of the site) is randomly subsampled, leading to an unacceptable lack of confidence in population estimates. Confidence is substantially improved using a multi-stage stratified approach based on previous information on distribution in the colonies. In reality, this could lead to reducing the number of plots required by up to 80%. Furthermore, power analyses suggested that random selection of monitoring plots using a matched pairs approach generates little power to detect overall population changes of 10%, and density-dependent changes as large as 50%, because variation in density between plots is so high. Current monitoring programs have a high probability of failing to detect population-level changes due to inappropriate sampling efforts. Focusing sampling in areas of high density with low plot to plot variance dramatically increases the power to detect year to year population change, albeit at the risk of not detecting increases in low density areas, which may be an unavoidable strategy when resources are limited. We discuss how challenging populations with similar features to seabirds might be censused and monitored most effectively.
- Published
- 2019
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39. Measuring Analytic Gradients of General Quantum Evolution with the Stochastic Parameter Shift Rule
- Author
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Leonardo Banchi and Gavin E. Crooks
- Subjects
Physics ,QC1-999 - Abstract
Hybrid quantum-classical optimization algorithms represent one of the most promising application for near-term quantum computers. In these algorithms the goal is to optimize an observable quantity with respect to some classical parameters, using feedback from measurements performed on the quantum device. Here we study the problem of estimating the gradient of the function to be optimized directly from quantum measurements, generalizing and simplifying some approaches present in the literature, such as the so-called parameter-shift rule. We derive a mathematically exact formula that provides a stochastic algorithm for estimating the gradient of any multi-qubit parametric quantum evolution, without the introduction of ancillary qubits or the use of Hamiltonian simulation techniques. The gradient measurement is possible when the underlying device can realize all Pauli rotations in the expansion of the Hamiltonian whose coefficients depend on the parameter. Our algorithm continues to work, although with some approximations, even when all the available quantum gates are noisy, for instance due to the coupling between the quantum device and an unknown environment.
- Published
- 2021
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40. Fibrin-mediated integrin signaling plays a critical role in hepatic regeneration after partial hepatectomy in mice
- Author
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Juliane I. Beier, Luping Guo, Swati Joshi-Barve, Jeffrey D. Ritzenthaler, Jesse Roman, and Gavin E. Arteel
- Subjects
Liver regeneration ,Fibrin(ogen) ,Extracellular matrix ,Alpha v beta 3 ,Endothelial cell damage ,Specialties of internal medicine ,RC581-951 - Abstract
Background. The regenerative capacity of the liver is critical for proper responses to injury. Fibrin extracellular matrix (ECM) deposition is a common response to insult and contributes to inflammatory liver injury. However, the role of this matrix in hepatic regeneration has not been determined. Objective. The purpose of this study was first to determine the role of fibrin ECM in hepatic regeneration followed by the role of the fibrin-binding αvβ3 integrin in mediating this effect.Material and methods. C57Bl/6J (WT) or PAI-1 knockout (KO) mice underwent 70% partial hepatectomy (PHx); plasma and histologic indices of regeneration were determined, as well as expression of key genes involved in hepatic regeneration.Results. PHx promoted transient fibrin deposition by activating coagulation and concomitantly decreasing fibrinolysis. Inhibiting fibrin deposition, either by blocking thrombin (hirudin) in WT mice or by knocking out PAI-1, was associated with a decrease in hepatocyte proliferation after PHx. This strongly suggested a role for fibrin ECM in liver regeneration. To investigate if avß3 integrin mediates this action, we tested the effects of the anti-αvβ3 cyclic peptide RGDfV in animals after PHx. As was observed with inhibition of fibrin deposition, competitive inhibition of αvβ3 integrin delayed regeneration after PHx, while not affecting fibrin deposition. These effects of RGDfV correlated with impaired angiogenesis and STAT3 signaling, as well as transient endothelial dysfunction. In conclusion, these data suggest that αvβ3 integrin plays an important role in coordinating hepatocyte division during liver regeneration after PHx via crosstalk with fibrin ECM.
- Published
- 2016
- Full Text
- View/download PDF
41. Effect of Expression of Human Glucosylceramidase 2 Isoforms on Lipid Profiles in COS-7 Cells
- Author
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Peeranat Jatooratthawichot, Chutima Talabnin, Lukana Ngiwsara, Yepy Hardi Rustam, Jisnuson Svasti, Gavin E. Reid, and James R. Ketudat Cairns
- Subjects
glycolipids ,sphingolipids ,cerebrosides ,ceramides ,lipidomics ,enzymology ,Microbiology ,QR1-502 - Abstract
Glucosylceramide (GlcCer) is a major membrane lipid and the precursor of gangliosides. GlcCer is mainly degraded by two enzymes, lysosomal acid β-glucosidase (GBA) and nonlysosomal β-glucosidase (GBA2), which may have different isoforms because of alternative splicing. To understand which GBA2 isoforms are active and how they affect glycosphingolipid levels in cells, we expressed nine human GBA2 isoforms in COS-7 cells, confirmed their expression by qRT-PCR and Western blotting, and assayed their activity to hydrolyze 4-methylumbelliferyl-β-D-glucopyranoside (4MUG) in cell extracts. Human GBA2 isoform 1 showed high activity, while the other isoforms had activity similar to the background. Comparison of sphingolipid levels by ultra-high resolution/accurate mass spectrometry (UHRAMS) analysis showed that isoform 1 overexpression increased ceramide and decreased hexosylceramide levels. Comparison of ratios of glucosylceramides to the corresponding ceramides in the extracts indicated that GBA2 isoform 1 has broad specificity for the lipid component of glucosylceramide, suggesting that only one GBA2 isoform 1 is active and affects sphingolipid levels in the cell. Our study provides new insights into how increased breakdown of GlcCer affects cellular lipid metabolic networks.
- Published
- 2020
- Full Text
- View/download PDF
42. Fixed-Depth Two-Qubit Circuits and the Monodromy Polytope
- Author
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Eric C. Peterson, Gavin E. Crooks, and Robert S. Smith
- Subjects
Physics ,QC1-999 - Abstract
For a native gate set which includes all single-qubit gates, we apply results from symplectic geometry to analyze the spaces of two-qubit programs accessible within a fixed number of gates. These techniques yield an explicit description of this subspace as a convex polytope, presented by a family of linear inequalities themselves accessible via a finite calculation. We completely describe this family of inequalities in a variety of familiar example cases, and as a consequence we highlight a certain member of the ``$\mathrm{XY}$--family'' for which this subspace is particularly large, i.e., for which many two-qubit programs admit expression as low-depth circuits.
- Published
- 2020
- Full Text
- View/download PDF
43. Intermittent Energy Restriction Attenuates the Loss of Fat Free Mass in Resistance Trained Individuals. A Randomized Controlled Trial
- Author
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Bill I. Campbell, Danielle Aguilar, Lauren M. Colenso-Semple, Kevin Hartke, Abby R. Fleming, Carl D. Fox, Jaymes M. Longstrom, Gavin E. Rogers, David B. Mathas, Vickie Wong, Sarah Ford, and John Gorman
- Subjects
fat loss ,resistance training ,physique enhancement ,diet ,weight loss ,bodybuilding ,sports nutrition ,refeed ,nutrition ,diet break ,Diseases of the musculoskeletal system ,RC925-935 - Abstract
There is a lack of research into how lean, resistance trained (RT) individuals respond to intermittent energy restricted diets. Therefore, we investigated body composition changes in RT-individuals during continuous energy restriction or intermittent restriction. A total of 27 males and females (25 ± 6.1 years; 169 ± 9.4 cm; 80 ± 15.6 kg) were randomized to a ~25% caloric restricted diet Refeed (RF; n = 13) or Continuous group (CN; n = 14) in conjunction with 4-days/week resistance training for 7-weeks. RF implemented two consecutive days of elevated carbohydrate (CHO) intake, followed by 5-days of caloric restriction each week. CN adhered to a continuous 7-week caloric restriction. Body mass (BM), fat mass (FM), fat-free mass (FFM), dry fat-free mass (dFFM), and resting metabolic rate (RMR) were assessed pre/post-diet. Both groups significantly reduced BM (RF: baseline = 76.4 ± 15.6 kg, post-diet = 73.2 ± 13.8 kg, Δ3.2 kg; CN: baseline = 83.1 ± 15.4 kg, post-diet = 79.5 ± 15 kg, Δ3.6 kg) and FM (RF: baseline = 16.3 ± 4 kg, post-diet = 13.5 ± 3.6 kg, Δ2.8 kg; CN: baseline = 16.7 ± 4.5 kg, post-diet = 14.4 ± 4.9 kg, Δ2.3 kg) with no differences between groups. FFM (RF: baseline = 60.1 ± 13.8 kg, post-diet = 59.7 ± 13.0 kg, 0.4 kg; CN: baseline = 66.4 ± 15.2 kg, post-diet = 65.1 ± 15.2 kg, Δ1.3 kg p = 0.006), dFFM (RF: baseline = 18.7 ± 5.0 kg, post-diet = 18.5 ± 4.5 kg, Δ0.2 kg; CN: baseline =21.9 ± 5.7 kg, post-diet = 20.0 ± 5.7 kg, Δ1.9 kg), and RMR (RF: baseline = 1703 ± 294, post-diet = 1,665 ± 270, Δ38 kcals; CN: baseline = 1867 ± 342, post-diet = 1789 ± 409, Δ78 kcals) were better maintained in the RF group. A 2-day carbohydrate refeed preserves FFM, dryFFM, and RMR during energy restriction compared to continuous energy restriction in RT-individuals.
- Published
- 2020
- Full Text
- View/download PDF
44. Thermodynamic Linear Algebra
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Aifer, Maxwell, Donatella, Kaelan, Gordon, Max Hunter, Duffield, Samuel, Ahle, Thomas, Simpson, Daniel, Crooks, Gavin E., and Coles, Patrick J.
- Subjects
Condensed Matter - Statistical Mechanics ,Computer Science - Emerging Technologies ,Quantum Physics - Abstract
Linear algebraic primitives are at the core of many modern algorithms in engineering, science, and machine learning. Hence, accelerating these primitives with novel computing hardware would have tremendous economic impact. Quantum computing has been proposed for this purpose, although the resource requirements are far beyond current technological capabilities, so this approach remains long-term in timescale. Here we consider an alternative physics-based computing paradigm based on classical thermodynamics, to provide a near-term approach to accelerating linear algebra. At first sight, thermodynamics and linear algebra seem to be unrelated fields. In this work, we connect solving linear algebra problems to sampling from the thermodynamic equilibrium distribution of a system of coupled harmonic oscillators. We present simple thermodynamic algorithms for (1) solving linear systems of equations, (2) computing matrix inverses, (3) computing matrix determinants, and (4) solving Lyapunov equations. Under reasonable assumptions, we rigorously establish asymptotic speedups for our algorithms, relative to digital methods, that scale linearly in matrix dimension. Our algorithms exploit thermodynamic principles like ergodicity, entropy, and equilibration, highlighting the deep connection between these two seemingly distinct fields, and opening up algebraic applications for thermodynamic computing hardware., Comment: 15+22 pages, 6 figures
- Published
- 2023
45. Potential Role of the Gut/Liver/Lung Axis in Alcohol-Induced Tissue Pathology
- Author
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Veronica L. Massey, Juliane I. Beier, Jeffrey D. Ritzenthaler, Jesse Roman, and Gavin E. Arteel
- Subjects
ethanol ,hepatic ,pulmonary ,inflammation ,extracellular matrix ,Microbiology ,QR1-502 - Abstract
Both Alcoholic Liver Disease (ALD) and alcohol-related susceptibility to acute lung injury are estimated to account for the highest morbidity and mortality related to chronic alcohol abuse and, thus, represent a focus of intense investigation. In general, alcohol-induced derangements to both organs are considered to be independent and are often evaluated separately. However, the liver and lung share many general responses to damage, and specific responses to alcohol exposure. For example, both organs possess resident macrophages that play key roles in mediating the immune/inflammatory response. Additionally, alcohol-induced damage to both organs appears to involve oxidative stress that favors tissue injury. Another mechanism that appears to be shared between the organs is that inflammatory injury to both organs is enhanced by alcohol exposure. Lastly, altered extracellular matrix (ECM) deposition appears to be a key step in disease progression in both organs. Indeed, recent studies suggest that early subtle changes in the ECM may predispose the target organ to an inflammatory insult. The purpose of this chapter is to review the parallel mechanisms of liver and lung injury in response to alcohol consumption. This chapter will also explore the potential that these mechanisms are interdependent, as part of a gut-liver-lung axis.
- Published
- 2015
- Full Text
- View/download PDF
46. Early embryo mortality in natural human reproduction: What the data say [version 2; referees: 1 approved, 2 approved with reservations]
- Author
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Gavin E. Jarvis
- Subjects
Pregnancy, Labor, Delivery & Postpartum Care ,Medicine ,Science - Abstract
How many human embryos die between fertilisation and birth under natural conditions? It is widely accepted that natural human embryo mortality is high, particularly during the first weeks after fertilisation, with total prenatal losses of 70% and higher frequently claimed. However, the first external sign of pregnancy occurs two weeks after fertilisation with a missed menstrual period, and establishing the fate of embryos before this is challenging. Calculations are additionally hampered by a lack of data on the efficiency of fertilisation under natural conditions. Four distinct sources are used to justify quantitative claims regarding embryo loss: (i) a hypothesis published by Roberts & Lowe in The Lancet is widely cited but has no practical quantitative value; (ii) life table analyses give consistent assessments of clinical pregnancy loss, but cannot illuminate losses at earlier stages of development; (iii) studies that measure human chorionic gonadotrophin (hCG) reveal losses in the second week of development and beyond, but not before; and (iv) the classic studies of Hertig and Rock offer the only direct insight into the fate of human embryos from fertilisation under natural conditions. Re-examination of Hertig’s data demonstrates that his estimates for fertilisation rate and early embryo loss are highly imprecise and casts doubt on the validity of his numerical analysis. A recent re-analysis of hCG study data concluded that approximately 40-60% of embryos may be lost between fertilisation and birth, although this will vary substantially between individual women. In conclusion, natural human embryo mortality is lower than often claimed and widely accepted. Estimates for total prenatal mortality of 70% or higher are exaggerated and not supported by the available data.
- Published
- 2017
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- View/download PDF
47. A monophasic extraction strategy for the simultaneous lipidome analysis of polar and nonpolar retina lipids[S]
- Author
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Todd A. Lydic, Julia V. Busik, and Gavin E. Reid
- Subjects
lipidomics ,lipid extraction ,mass spectrometry ,ganglioside ,glycerolipid ,sphingolipid ,Biochemistry ,QD415-436 - Abstract
Lipid extraction using a monophasic chloroform/methanol/water mixture, coupled with functional group selective derivatization and direct infusion nano-ESI-high-resolution/accurate MS, is shown to facilitate the simultaneous analysis of both highly polar and nonpolar lipids from a single retina lipid extract, including low abundance highly polar ganglioside lipids, nonpolar sphingolipids, and abundant glycerophospholipids. Quantitative comparison showed that the monophasic lipid extraction method yielded similar lipid distributions to those obtained from established “gold standard” biphasic lipid extraction methods known to enrich for either highly polar gangliosides or nonpolar lipids, respectively, with only modest relative ion suppression effects. This improved lipid extraction and analysis strategy therefore enables detailed lipidome analyses of lipid species across a broad range of polarities and abundances, from minimal amounts of biological samples and without need for multiple lipid class-specific extractions or chromatographic separation prior to analysis.
- Published
- 2014
- Full Text
- View/download PDF
48. Estimating limits for natural human embryo mortality [version 2; referees: 2 approved]
- Author
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Gavin E. Jarvis
- Subjects
Female Fertility Regulation ,Pregnancy, Labor, Delivery & Postpartum Care ,Reproductive Physiology ,Medicine ,Science - Abstract
Natural human embryonic mortality is generally considered to be high. Values of 70% and higher are widely cited. However, it is difficult to determine accurately owing to an absence of direct data quantifying embryo loss between fertilisation and implantation. The best available data for quantifying pregnancy loss come from three published prospective studies (Wilcox, Zinaman and Wang) with daily cycle by cycle monitoring of human chorionic gonadotrophin (hCG) in women attempting to conceive. Declining conception rates cycle by cycle in these studies indicate that a proportion of the study participants were sub-fertile. Hence, estimates of fecundability and pre-implantation embryo mortality obtained from the whole study cohort will inevitably be biased. This new re-analysis of aggregate data from these studies confirms the impression that discrete fertile and sub-fertile sub-cohorts were present. The proportion of sub-fertile women in the three studies was estimated as 28.1% (Wilcox), 22.8% (Zinaman) and 6.0% (Wang). The probability of conceiving an hCG pregnancy (indicating embryo implantation) was, respectively, 43.2%, 38.1% and 46.2% among normally fertile women, and 7.6%, 2.5% and 4.7% among sub-fertile women. Pre-implantation loss is impossible to calculate directly from available data although plausible limits can be estimated. Based on this new analysis and a model for evaluating reproductive success and failure it is proposed that a plausible range for normal human embryo and fetal mortality from fertilisation to birth is 40-60%.
- Published
- 2016
- Full Text
- View/download PDF
49. n-3 PUFAs enhance the frequency of murine B-cell subsets and restore the impairment of antibody production to a T-independent antigen in obesity[S]
- Author
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Heather Teague, Cassie J. Fhaner, Mitchel Harris, David M. Duriancik, Gavin E. Reid, and Saame Raza Shaikh
- Subjects
humoral immunity ,eicosapentaenoic acid ,docosahexaenoic acid ,Biochemistry ,QD415-436 - Abstract
The role of n-3 polyunsaturated fatty acids (PUFA) on in vivo B-cell immunity is unknown. We first investigated how n-3 PUFAs impacted in vivo B-cell phenotypes and antibody production in the absence and presence of antigen compared with a control diet. Lean mice consuming n-3 PUFAs for 4 weeks displayed increased percentage and frequency of splenic transitional 1 B cells. Upon stimulation with trinitrophenylated-lipopolysaccharide, n-3 PUFAs increased the number of splenic transitional 1/2, follicular, premarginal, and marginal zone B cells. n-3 PUFAs also increased surface, but not circulating, IgM. We next tested the effects of n-3 PUFAs in a model of obesity that is associated with suppressed humoral immunity. An obesogenic diet after ten weeks of feeding, relative to a lean control, had no effect on the frequency of B cells but lowered circulating IgM upon antigen stimulation. Administration of n-3 PUFAs to lean and obese mice increased the percentage and/or frequency of transitional 1 and marginal zone B cells. Furthermore, n-3 PUFAs in lean and obese mice increased circulating IgM relative to controls. Altogether, the data show n-3 PUFAs enhance B cell-mediated immunity in vivo, which has implications for immunocompromised populations, such as the obese.
- Published
- 2013
- Full Text
- View/download PDF
50. Early embryo mortality in natural human reproduction: What the data say [version 1; referees: 1 approved, 2 approved with reservations]
- Author
-
Gavin E. Jarvis
- Subjects
Pregnancy, Labor, Delivery & Postpartum Care ,Medicine ,Science - Abstract
It is generally accepted that natural human embryo mortality during pregnancy is high – losses of 70% and higher from fertilisation to birth are frequently claimed. The first external sign of pregnancy occurs two weeks after fertilisation with a missed menstrual period. Establishing the fate of embryos before this is challenging, and hampered by a lack of data on the efficiency of fertilisation under natural conditions. Four distinct sources are cited to justify quantitative claims regarding embryo loss: (i) a hypothesis published by Roberts & Lowe in The Lancet is widely cited but has no quantitative value; (ii) life table analyses give consistent assessments of clinical pregnancy loss, but cannot illuminate losses at earlier stages of development; (iii) studies that measure human chorionic gonadotrophin (hCG) reveal losses in the second week of development and beyond, but not before; and (iv) the classic studies of Hertig and Rock offer the only direct insight into the fate of human embryos from fertilisation under natural conditions. Re-examination of Hertig’s data demonstrates that his estimates for fertilisation rate and early embryo loss are highly imprecise and casts doubt on the validity of his numerical analysis. A recent re-analysis of hCG study data suggests that approximately 40-60% of embryos may be lost between fertilisation and birth, although this will vary substantially between individual women. In conclusion, it is clear that some published estimates of natural embryo mortality are exaggerated. Although available data do not provide a precise estimate, natural human embryo mortality is lower than is often claimed.
- Published
- 2016
- Full Text
- View/download PDF
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