471 results on '"R. Dent"'
Search Results
2. Suicide among Veterans in Veterans Health Administration care: Differences in methods by tier of predicted suicide risk
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Kallisse R. Dent, Molly Goodrich, Stephanie A. Gamble, and John F. McCarthy
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Firearms ,Prediction ,Means safety ,Lethal means ,Psychiatry ,RC435-571 - Abstract
Veterans' suicide rates exceed those of non-Veteran adults, and Veteran suicides more often involve firearms. However, the relationship between Veteran characteristics and suicide method is not well understood. Using the Veteran Health Administration suicide prediction algorithm, we assessed differences in suicide method by predicted risk among Veteran suicide decedents. Significant predictors of firearm involvement included lower algorithm-predicted suicide risk, no recent suicide attempts, male sex, and older age. Non-firearm methods were most common at high tiers of suicide risk. Firearm safety counseling is important for all Veterans and non-firearm lethal means safety counseling may be particularly important for high-risk Veterans.
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- 2024
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3. USP22 overexpression fails to augment tumor formation in MMTV-ERBB2 mice but loss of function impacts MMTV promoter activity
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Xianghong Kuang, Andrew Salinger, Fernando Benavides, William J. Muller, Sharon Y. R. Dent, and Evangelia Koutelou
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Medicine ,Science - Published
- 2024
4. Engineering neuroglobin nitrite reductase activity based on myoglobin models
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Mark D. Williams, Venkata Ragireddy, Matthew R. Dent, and Jesús Tejero
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Neuroglobin ,Nitrite reduction ,Nitric oxide ,Protein engineering ,Biology (General) ,QH301-705.5 ,Biochemistry ,QD415-436 - Abstract
Neuroglobin is a hemoprotein expressed in several nervous system cell lineages with yet unknown physiological functions. Neuroglobin presents a very similar structure to that of the related globins hemoglobin and myoglobin, but shows an hexacoordinate heme as compared to the pentacoordinated heme of myoglobin and hemoglobin. While several reactions of neuroglobin have been characterized in vitro, the relative importance of most of those reactions in vivo is yet undefined. Neuroglobin, like other heme proteins, can reduce nitrite to nitric oxide, providing a possible route to generate nitric oxide in vivo in low oxygen conditions. The reaction kinetics are highly dependent on the nature of the distal residue, and replacement of the distal histidine His64(E7) can increase the reaction rate constants by several orders of magnitude. However, mutation of other distal pocket positions such as Phe28(B10) or Val68(E11) has more limited impact on the rates. Computational analysis using myoglobin as template, guided by the structure of dedicated nitrite reductases like cytochrome cd1 nitrite reductase, has pointed out that combined mutations of the residues B10 and CD1 could increase the nitrite reductase activity of myoglobin, by mimicking the environment of the distal heme pocket in cytochrome cd1 nitrite reductase. As neuroglobin shows high sequence and structural homology with myoglobin, we hypothesized that such mutations (F28H and F42Y in neuroglobin) could also modify the nitrite reductase activity of neuroglobin. Here we study the effect of these mutations. Unfortunately, we do not observe in any case an increase in the nitrite reduction rates. Our results provide some further indications of nitrite reductase regulation in neuroglobin and highlight the minor but critical differences between the structure of penta- and hexacoordinate globins.
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- 2023
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5. Conservation and diversity of the eukaryotic SAGA coactivator complex across kingdoms
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Ying-Jiun C. Chen and Sharon Y. R. Dent
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SAGA complex ,Transcription ,Coactivator ,Epigenetics ,GCN5 ,Development ,Genetics ,QH426-470 - Abstract
Abstract The SAGA complex is an evolutionarily conserved transcriptional coactivator that regulates gene expression through its histone acetyltransferase and deubiquitylase activities, recognition of specific histone modifications, and interactions with transcription factors. Multiple lines of evidence indicate the existence of distinct variants of SAGA among organisms as well as within a species, permitting diverse functions to dynamically regulate cellular pathways. Our co-expression analysis of genes encoding human SAGA components showed enrichment in reproductive organs, brain tissues and the skeletal muscle, which corresponds to their established roles in developmental programs, emerging roles in neurodegenerative diseases, and understudied functions in specific cell types. SAGA subunits modulate growth, development and response to various stresses from yeast to plants and metazoans. In metazoans, SAGA further participates in the regulation of differentiation and maturation of both innate and adaptive immune cells, and is associated with initiation and progression of diseases including a broad range of cancers. The evolutionary conservation of SAGA highlights its indispensable role in eukaryotic life, thus deciphering the mechanisms of action of SAGA is key to understanding fundamental biological processes throughout evolution. To illuminate the diversity and conservation of this essential complex, here we discuss variations in composition, essentiality and co-expression of component genes, and its prominent functions across Fungi, Plantae and Animalia kingdoms.
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- 2021
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6. Transient changes to metabolic homeostasis initiate mitochondrial adaptation to endurance exercise
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Jessica R. Dent, Ben Stocks, Dean G. Campelj, and Andrew Philp
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Cell Biology ,Developmental Biology - Abstract
Endurance exercise is well established to increase mitochondrial content and function in skeletal muscle, a process termed mitochondrial biogenesis. Current understanding is that exercise initiates skeletal muscle mitochondrial remodeling via modulation of cellular nutrient, energetic and contractile stress pathways. These subtle changes in the cellular milieu are sensed by numerous transduction pathways that serve to initiate and coordinate an increase in mitochondrial gene transcription and translation. The result of these acute signaling events is the promotion of growth and assembly of mitochondria, coupled to a greater capacity for aerobic ATP provision in skeletal muscle. The aim of this review is to highlight the acute metabolic events induced by endurance exercise and the subsequent molecular pathways that sense this transient change in cellular homeostasis to drive mitochondrial adaptation and remodeling.
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- 2023
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7. No evidence of hemoglobin damage by SARS-CoV-2 infection
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Anthony W. DeMartino, Jason J. Rose, Matthew B. Amdahl, Matthew R. Dent, Faraaz A. Shah, William Bain, Bryan J. McVerry, Georgios D. Kitsios, Jesús Tejero, and Mark T. Gladwin
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Diseases of the blood and blood-forming organs ,RC633-647.5 - Abstract
SARS-CoV-2 disease (COVID-19) has affected over 22 million patients worldwide as of August 2020. As the medical community seeks better understanding of the underlying pathophysiology of COVID-19, several theories have been proposed. One widely shared theory suggests that SARS-CoV-2 proteins directly interact with human hemoglobin (Hb) and facilitate removal of iron from the heme prosthetic group, leading to the loss of functional hemoglobin and accumulation of iron. Herein, we refute this theory. We compared clinical data from 21 critically ill COVID-19 patients to 21 non-COVID-19 ARDS patient controls, generating hemoglobin-oxygen dissociation curves from venous blood gases. This curve generated from the COVID-19 cohort matched the idealized oxygen-hemoglobin dissociation curve well (Pearson correlation, R2 = 0.97, P
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- 2020
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8. Body surface mapping using an ECG belt to characterize electrical heterogeneity for different left ventricular pacing sites during cardiac resynchronization: Relationship with acute hemodynamic improvement
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Johnson, W. Ben, Vatterott, Pierce J., Peterson, Michael A., Bagwe, Suveer, Underwood, R. Dent, Bank, Alan J., Gage, Ryan M., Ramza, Brian, Foreman, Blair W., Splett, Vincent, Haddad, Tarek, Gillberg, Jeffrey M., and Ghosh, Subham
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- 2017
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9. Histone modification profiling in breast cancer cell lines highlights commonalities and differences among subtypes
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Yuanxin Xi, Jiejun Shi, Wenqian Li, Kaori Tanaka, Kendra L. Allton, Dana Richardson, Jing Li, Hector L. Franco, Anusha Nagari, Venkat S. Malladi, Luis Della Coletta, Melissa S. Simper, Khandan Keyomarsi, Jianjun Shen, Mark T. Bedford, Xiaobing Shi, Michelle C. Barton, W. Lee Kraus, Wei Li, and Sharon Y. R. Dent
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Breast cancer subtypes ,Epigenetics ,Histone modifications ,Chromatin states ,Biotechnology ,TP248.13-248.65 ,Genetics ,QH426-470 - Abstract
Abstract Background Epigenetic regulators are frequently mutated or aberrantly expressed in a variety of cancers, leading to altered transcription states that result in changes in cell identity, behavior, and response to therapy. Results To define alterations in epigenetic landscapes in breast cancers, we profiled the distributions of 8 key histone modifications by ChIP-Seq, as well as primary (GRO-seq) and steady state (RNA-Seq) transcriptomes, across 13 distinct cell lines that represent 5 molecular subtypes of breast cancer and immortalized human mammary epithelial cells. Discussion Using combinatorial patterns of distinct histone modification signals, we defined subtype-specific chromatin signatures to nominate potential biomarkers. This approach identified AFAP1-AS1 as a triple negative breast cancer-specific gene associated with cell proliferation and epithelial-mesenchymal-transition. In addition, our chromatin mapping data in basal TNBC cell lines are consistent with gene expression patterns in TCGA that indicate decreased activity of the androgen receptor pathway but increased activity of the vitamin D biosynthesis pathway. Conclusions Together, these datasets provide a comprehensive resource for histone modification profiles that define epigenetic landscapes and reveal key chromatin signatures in breast cancer cell line subtypes with potential to identify novel and actionable targets for treatment.
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- 2018
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10. YEATS2 links histone acetylation to tumorigenesis of non-small cell lung cancer
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Wenyi Mi, Haipeng Guan, Jie Lyu, Dan Zhao, Yuanxin Xi, Shiming Jiang, Forest H. Andrews, Xiaolu Wang, Mihai Gagea, Hong Wen, Laszlo Tora, Sharon Y. R. Dent, Tatiana G. Kutateladze, Wei Li, Haitao Li, and Xiaobing Shi
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Science - Abstract
Histone modification recognition is an important mechanism for gene expression regulation in cancer. Here, the authors identify YEATS2 as a histone H3K27ac reader, regulating a transcriptional program essential for tumorigenesis in human non-small cell lung cancer.
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- 2017
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11. Resistance exercise initiates mechanistic target of rapamycin (mTOR) translocation and protein complex co-localisation in human skeletal muscle
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Zhe Song, Daniel R. Moore, Nathan Hodson, Carl Ward, Jessica R. Dent, Mary F. O’Leary, Andrew M. Shaw, D. Lee Hamilton, Sovan Sarkar, Yann-Gaël Gangloff, Troy A. Hornberger, Lawrence L. Spriet, George J. Heigenhauser, and Andrew Philp
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Medicine ,Science - Abstract
Abstract The mechanistic target of rapamycin (mTOR) is a central mediator of protein synthesis in skeletal muscle. We utilized immunofluorescence approaches to study mTOR cellular distribution and protein-protein co-localisation in human skeletal muscle in the basal state as well as immediately, 1 and 3 h after an acute bout of resistance exercise in a fed (FED; 20 g Protein/40 g carbohydrate/1 g fat) or energy-free control (CON) state. mTOR and the lysosomal protein LAMP2 were highly co-localised in basal samples. Resistance exercise resulted in rapid translocation of mTOR/LAMP2 towards the cell membrane. Concurrently, resistance exercise led to the dissociation of TSC2 from Rheb and increased in the co-localisation of mTOR and Rheb post exercise in both FED and CON. In addition, mTOR co-localised with Eukaryotic translation initiation factor 3 subunit F (eIF3F) at the cell membrane post-exercise in both groups, with the response significantly greater at 1 h of recovery in the FED compared to CON. Collectively our data demonstrate that cellular trafficking of mTOR occurs in human muscle in response to an anabolic stimulus, events that appear to be primarily influenced by muscle contraction. The translocation and association of mTOR with positive regulators (i.e. Rheb and eIF3F) is consistent with an enhanced mRNA translational capacity after resistance exercise.
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- 2017
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12. Differences in the localization of AQP1 and expression patterns of AQP isoforms in rat and mouse sciatic nerve and changes in rat AQPs expression after nerve crush injury
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Edith, Segura-Anaya, Alejandro, Martínez-Gómez, and Myrna A R, Dent
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Nerve injury ,Remak cells ,General Neuroscience ,Wallerian degeneration ,Schwann cells ,Neurosciences. Biological psychiatry. Neuropsychiatry ,Peripheral nervous system ,Aquaporins ,Article ,RC321-571 - Abstract
In the peripheral nervous system aquaporins (AQPs) have been reported in both peripheral neurons and glial cells. Previously we described the precise localization of AQP1 in the rat sciatic nerve, which is present in both Remak and myelin Schwann cells, and is enriched in the Schmidt-Lanterman incisures. In this work, we found that AQP1 in mouse is only present in Remak cells, showing a different localization between these species. However, after nerve crush injury the level of AQP1 mRNA expression remains constant at all times studied in rat and mouse. We then performed RT-PCR of nine AQP (AQP1–9) isoforms from rat and mouse sciatic nerve, we found that in rat only five AQPs are present (AQP1, AQP4, AQP5, AQP7 and AQP9), whereas in mouse all AQPs except AQP8 are expressed. Then, we studied the expression by RT-PCR of AQPs in rat after nerve crush injury, showing that AQP1, AQP4 and AQP7 expression remain constant at all times studied, while AQP2, AQP5 and AQP9 are upregulated after injury. Therefore, these two closely related rodents show different AQP1 localization and have different AQPs expression patterns in the sciatic nerve, possibly due to a difference in the regulation of these AQPs. The expression of AQP1 in Remak cells supports the involvement of AQP1 in pain perception. Also, in rat the upregulation of AQP2, AQP5 and AQP7 after nerve injury suggests a possible role for these AQPs in promoting regeneration following injury.
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- 2022
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13. Quaternary Structure and Deoxyribonucleic Acid-Binding Properties of the Heme-Dependent, CO-Sensing Transcriptional Regulator PxRcoM
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Matthew R. Dent, Madeleine G. Roberts, Hannah E. Bowman, Brian R. Weaver, Darrell R. McCaslin, and Judith N. Burstyn
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Hemeproteins ,Carbon Monoxide ,Bacterial Proteins ,DNA ,Heme ,Biochemistry ,Protein Binding ,Transcription Factors - Abstract
RcoM, a heme-containing, CO-sensing transcription factor, is one of two known bacterial regulators of CO metabolism. Unlike its analogue CooA, the structure and DNA-binding properties of RcoM remain largely uncharacterized. Using a combination of size exclusion chromatography and sedimentation equilibrium, we demonstrate that RcoM-1 from
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- 2022
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14. Carbon Monoxide-Sensing Transcription Factors: Regulators of Microbial Carbon Monoxide Oxidation Pathway Gene Expression
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Matthew R. Dent, Brian R. Weaver, Madeleine G. Roberts, and Judith N. Burstyn
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Molecular Biology ,Microbiology - Abstract
Carbon monoxide (CO) serves as a source of energy and carbon for a diverse set of microbes found in anaerobic and aerobic environments. The enzymes that bacteria and archaea use to oxidize CO depend upon complex metallocofactors that require accessory proteins for assembly and proper function.
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- 2023
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15. Grand challenge in chromatin epigenomics: everything, everywhere, all at once
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Sharon Y. R. Dent
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Our understanding of the regulation and functions of histone modifications has come a long way since they were first reported in the mid-1960s. So too has our understanding of the importance of DNA methylation, histone variants, nucleosome locations and arrangements, and progressively higher order structures that impact when and where DNA-templated processes take place. Recent advances have even allowed the first ever complete sequencing and epigenomic profiles of individual chromosomes from telomere to telomere, including highly repetitive regions that were previously refractory to analysis. The regulatory power of chromatin organization for gene transcription, DNA replication, recombination and repair is undisputable. Still, an ongoing challenge is to understand the full spectrum of changes (everything) that impact processes in cells and tissues (everywhere) and how each change impacts others (all at once).
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- 2023
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16. Microplastic burden in invasive signal crayfish ( Pacifastacus leniusculus ) increases along a stream urbanization gradient
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Abigail R. Dent, Daniel D. A. Chadwick, Lawrence J. B. Eagle, Alex N. Gould, Matthew Harwood, Carl D. Sayer, and Neil L. Rose
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Ecology ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Published
- 2023
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17. Viscosity-sensitive membrane dyes as tools to estimate the crystalline structure of lipid bilayers
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Miguel Paez-Perez, Michael R. Dent, Nicholas J. Brooks, and Marina K. Kuimova
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Lipid membranes are crucial for cellular integrity and regulation, and tight control of their structural and mechanical properties is vital to ensure that they function properly. Fluorescent probes sensitive to the mem-brane’s microenvironment are useful for investigating lipid membrane properties, however, there is currently a lack of quantitative correlation between the exact parameters of lipid organization and a readout from these dyes. Here, we investigate this relationship for ‘molecular rotors’, or microviscosity sensors, by simultaneously measuring their fluorescence lifetime to determine the membrane viscosity, while using the X-Ray diffraction the determine the membrane’s structural properties. Our results reveal a phase-dependent correlation be-tween the membrane’s structural parameters and mechanical properties measured by a BODIPY-based mo-lecular rotor, giving excellent predictive power for the structural descriptors of the lipid bilayer. We also demonstrate that differences in membrane thickness between different lipid phases is not a prerequisite for formation of lipid microdomains and that this requirement can be disrupted by the presence of line-active molecules. Our results underpin the use of membrane-sensitive dyes as reporters of the structure of lipid membranes.
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- 2023
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18. Challenges in oncology career: are we closing the gender gap? Results of the new ESMO Women for Oncology Committee survey
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H. Linardou, A.A. Adjei, J. Bajpai, S. Banerjee, A.S. Berghoff, C. Cerqueira Mathias, S.P. Choo, R. Dent, E. Felip, A.J.S. Furness, M.C. Garassino, E. Garralda, A. Konsoulova-Kirova, A. Letsch, A.M. Menzies, D. Mukherji, S. Peters, C. Sessa, J. Tsang, J.C.-H. Yang, P. Garrido, Institut Català de la Salut, [Linardou H] 4th Oncology Department & Comprehensive Clinical Trials Centre, Metropolitan Hospital, Athens, Greece. [Adjei AA] Mayo Clinic, Rochester, USA. [Bajpai J] Tata Memorial Centre, Homi-bhabha National Institute, Mumbai, India. [Banerjee S] The Royal Marsden NHS Foundation Trust, Institute of Cancer Research, London, UK. [Berghoff AS] Division of Oncology, Department of Medicine 1, Medical University of Vienna, Vienna, Austria. [Mathias CC] Grupo Oncoclinicas and Hospital Santa Izabel, Bahia, Brazil. [Felip E] Servei d’Oncologia Mèdica, Vall d’Hebron Hospital Universitari, Barcelona, Spain. Thoracic Oncology and H&N Cancer Unit, Vall d’Hebron Institute of Oncology (VHIO), Barcelona, Spain. UVic-UCC, Barcelona, Spain. [Garralda E] Early Drug Development Unit, Vall d’Hebron Institute of Oncology (VHIO), Barcelona, Spain. Vall d’Hebron Hospital Universitari, Barcelona, Spain, and Vall d'Hebron Barcelona Hospital Campus
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Lideratge ,Investigative Techniques::Epidemiologic Methods::Data Collection::Surveys and Questionnaires [ANALYTICAL, DIAGNOSTIC AND THERAPEUTIC TECHNIQUES, AND EQUIPMENT] ,Cancer Research ,Oncologia ,personas::mujeres [DENOMINACIONES DE GRUPOS] ,Dones ,técnicas de investigación::métodos epidemiológicos::recopilación de datos::encuestas y cuestionarios [TÉCNICAS Y EQUIPOS ANALÍTICOS, DIAGNÓSTICOS Y TERAPÉUTICOS] ,Behavior and Behavior Mechanisms::Personality::Leadership [PSYCHIATRY AND PSYCHOLOGY] ,Enquestes ,conducta y mecanismos de la conducta::personalidad::liderazgo [PSIQUIATRÍA Y PSICOLOGÍA] ,profesiones sanitarias::medicina::medicina interna::oncología médica [DISCIPLINAS Y OCUPACIONES] ,Oncology ,Persons::Women [NAMED GROUPS] ,Health Occupations::Medicine::Internal Medicine::Medical Oncology [DISCIPLINES AND OCCUPATIONS] - Abstract
Discrimination; Gender equity; Oncology Discriminació; Equitat de gènere; Oncologia Discriminación; Equidad de género; Oncología Background Following a European Society for Medical Oncology Women for Oncology (ESMO W4O) survey in 2016 showing severe under-representation of female oncologists in leadership roles, ESMO launched a series of initiatives to address obstacles to gender equity. A follow-up survey in October 2021 investigated progress achieved. Materials and methods The W4O questionnaire 2021 expanded on the 2016 survey, with additional questions on the impact of ethnicity, sexual orientation and religion on career development. Results were analysed according to respondent gender and age. Results The survey sample was larger than in 2016 (n = 1473 versus 482), especially among men. Significantly fewer respondents had managerial or leadership roles than in 2016 (31.8% versus 51.7%). Lack of leadership development for women and unconscious bias were considered more important in 2021 than in 2016. In 2021, more people reported harassment in the workplace than in 2016 (50.3% versus 41.0%). In 2021, ethnicity, sexual orientation and religion were considered to have little or no impact on professional career opportunities, salary setting or related potential pay gap. However, gender had a significant or major impact on career development (25.5% of respondents), especially in respondents ≤40 years of age and women. As in 2016, highest ranked initiatives to foster workplace equity were promotion of work–life balance, development and leadership training and flexible working. Significantly more 2021 respondents (mainly women) supported the need for culture and gender equity education at work than in 2016. Conclusions Gender remains a major barrier to career progression in oncology and, although some obstacles may have been reduced since 2016, we are a long way from closing the gender gap. Increased reporting of discrimination and inappropriate behaviour in the workplace is a major, priority concern. The W4O 2021 survey findings provide new evidence and highlight the areas for future ESMO interventions to support equity and diversity in oncology career development. This work was supported by the European Society for Medical Oncology (no grant number).
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- 2023
19. Trading species to extinction: evidence of extinction linked to the wildlife trade
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Amy Hinsley, Jasmin Willis, Abigail R. Dent, Rodrigo Oyanedel, Takahiro Kubo, and Daniel W. S. Challender
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The link between unsustainable harvest of species for the wildlife trade and extinction is clear in some cases, but little is known about the number of species across taxonomic groups that have gone extinct because of trade-related factors, or future risks for traded species. We conducted a rapid review of published articles and species assessments on the IUCN Red List of Threatened Species with the aim of recording examples of extinctions that were attributed to trade. We found reports of extinctions linked, at least in part, to wildlife trade for 511 unique taxa. These include 294 reports of global extinctions, 25 extinctions in the wild, and 192 local extinctions. The majority of global/in the wild extinctions linked to trade (230) involved ray-finned fishes, primarily due to predation by introduced commercial species. Seventy-one of the 175 reported local extinctions of animal taxa linked to trade were mammals. Twenty-two global/in the wild extinctions and 16 local extinctions of plants were reportedly linked to trade. One fungal species was reported locally extinct due to over-harvesting for trade. Furthermore, 340 species were reported to be near-extinct linked to trade, 269 of which were animals, including several high-profile megafauna. Extinctions were linked to direct harvesting and/or indirect threats such as bycatch or invasive species introduced for trade, but often it was not possible to determine the relative role of trade-related threats in extinctions. Our results highlight the need for better data collection on trade-related extinction risk to understand its impacts and to inform more effective wildlife trade policy.
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- 2023
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20. Viscosity-sensitive membrane dyes as tools to estimate the crystal-line structure of lipid bilayers
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Miguel Paez-Perez, Michael R. Dent, Nicholas J. Brooks, and Marina K. Kuimova
- Abstract
Lipid membranes are crucial for cellular metabolism, and their correct function has been linked to a tight regulation of their structural and mechanical properties, such as viscosity. Fluorescent probes sensitive to the membrane’s environ- are being extensively used to investigate the membrane’s properties, yet there is currently a lack of understanding on how the lipid organization impacts the readout from these dyes. Here, we investigate this relationship by simultaneously characterizing the membrane’s viscosity and structural properties using a combination of X-Ray diffraction, together with environmentally-sensitive optical membrane probes and fluorescence lifetime imaging microscopy. Our results reveal a phase-dependent connection between the different membrane’s structural and mechanical parameters and give insight into the relationship between two widely used membrane probes with the structural descriptors of the lipid bi-layer. Such relationship is believed to dictate the lateral organization of lipid bilayers, including the presence of distinct lipid domains which have been traditionally ascribed to a difference in the membrane thickness of the lipid phases; yet we later demonstrate how such connection is not universal and can disrupted by the presence of line-active molecules. Our results show the capability of membrane dyes to directly report on the membrane’s molecular structure – after appropriate calibration – and highlight the need of multiple orthogonal characterization strategies for a proper understanding of the membrane’s properties.
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- 2023
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21. Navigating EMT with COMPASS and PRC2
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Evangelia Koutelou and Sharon Y. R. Dent
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Cell Biology - Published
- 2022
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22. A285 CHANGE IN ALT DURING MODIFIED OPTIFAST WEIGHT LOSS PROGRAM IN INDIVIDUALS AT RISK FOR NON-ALCOHOLIC FATTY LIVER DISEASE
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L Meddings Maybury, E Kelly, R Dent, and B Bielawska
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Background Obesity is linked to various health complications, including diabetes, metabolic syndrome, cardiovascular disease, and non-alcoholic fatty liver disease (NAFLD). NAFLD is the most frequent cause of abnormally high alanine aminotransferase (ALT) levels. ALT is released at higher levels during hepatocellular injury and represents a simple, low cost and non-invasive method of assessing liver damage. There are conflicting data on ALT response to weight loss between men and women, with some evidence of transient increase in ALT levels in women. Purpose The aim of this study was to assess the impact of a dietary weight loss intervention with Optifast on ALT in patients with obesity who have baseline elevated ALT levels. Method This was a retrospective cohort study of Ontario adults who participated in a 26 week weight loss program, including 6 or 12 weeks of low-calorie liquid diet meal replacement with Optifast 900® (Nestlé, Canada), between 1992 and 2015. We included patients with elevated baseline ALT levels, defined by > 40 U/L, who had at least one follow-up ALT between week 15 and 26. We excluded patients with nonadherence to dietary intervention, established liver disease or using hepatotoxic drugs, excessive alcohol intake (>11U/wk for females and >14U/wk for males), and insufficient data to calculate FIB-4. The primary outcome was change in ALT levels, measured by normalization (post-intervention ALT < 40 U/L), percentage decrease and absolute decrease. Multiple linear regressions were obtained for the relationship between ALT changes and age, sex, body mass index (BMI) and FIB-4. All analyses were conducted in SPSS. P value of ≤0.05 was considered statistically significant. Result(s) 444 patients met study criteria. Mean age was 47.1 years +/- 10.9, 49 % of patients were female, and mean BMI was 43.5 kg/m2 +/- 7.9. All patients lost weight, with mean weight loss 27.3 kg +/- 11.5 and a mean 20.7% decrease from baseline weight. Mean ALT at baseline was 58.9 U/L +/- 25.4 and mean ALT post intervention was 32.3 U/L +/- 28.1 (p Conclusion(s) In patients with obesity and baseline elevated ALT, dietary weight loss intervention with Optifast leads to ALT normalization in most patients, regardless of sex. Younger age at baseline and higher baseline FIB-4 are significantly associated with greater decrease in ALT. Please acknowledge all funding agencies by checking the applicable boxes below None Disclosure of Interest None Declared
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- 2023
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23. USP22 overexpression fails to augment tumor formation in MMTV-ERBB2 mice but loss of function impacts MMTV promoter activity
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Xianghong Kuang, Andrew Salinger, Fernando Benavides, William J. Muller, Sharon Y. R. Dent, and Evangelia Koutelou
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The USP22 deubiquitinase, a component of the SAGA histone modifying complex, is overexpressed in multiple human cancers, but how USP22 impacts tumorigenesis is not clear. We reported previously that Usp22 loss in mice impacts execution of several signaling pathways driven by growth factor receptors such as ERBB2. To determine whether changes in USP22 expression affects ERBB2-driven tumorigenesis, we introduced conditional overexpression or deletion alleles of Usp22 into mice bearing the MMTV-NIC transgene, which drives both rat ERBB2/NEU expression and Cre recombinase activity from the MMTV promoter resulting in mammary tumor formation. We found that USP22 overexpression in mammary glands did not further enhance primary tumorigenesis in MMTV-NIC female mice, but increased lung metastases were observed. However, deletion of Usp22 significantly decreased tumor burden and increased survival of MMTV-NIC mice. These effects were associated with markedly decreased levels of both Erbb2 mRNA and protein, indicating Usp22 loss impacts MMTV promoter activity. Usp22 loss had no impact on ERBB2 expression in other settings, including MCF10A cells bearing a CMV-driven ERBB2 transgene or in HER2+ human SKBR3 and HCC1953 cells. Decreased activity of the MMTV promoter in MMTV-NIC mice correlated with decreased expression of known regulatory factors, including the glucocorticoid receptor (GR), the progesterone receptor (PR), and the chromatin remodeling factor BRG1. Together our findings indicate that increased expression of USP22 does not augment the activity of an activated ERBB2/NEU transgene, but impacts of Usp22 loss on tumorigenesis cannot be assessed in this model due to unexpected effects on MMTV-driven Erbb2/Neu expression.SignificanceOverexpression of USP22 alone is not sufficient to promote MMTV-ERBB2-driven tumor formation but may enhance metastasis. Usp22 loss impacts expression of GR, PR and BRG1, decreasing MMTV promoter activity.
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- 2022
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24. Metabolic Syndrome Mediates ROS-miR-193b-NFYA–Dependent Downregulation of Soluble Guanylate Cyclase and Contributes to Exercise-Induced Pulmonary Hypertension in Heart Failure With Preserved Ejection Fraction
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Scott A. Hahn, Ying Tang, Mark T. Gladwin, Taijyu Satoh, Charles F. McTiernan, Kentaro Noda, Cynthia St. Hilaire, Bing Wang, Adam C. Straub, Samuel K. Wyman, Cristina Espinosa-Diez, Georgios Triantafyllou, Jeffrey J. Baust, Sruti Shiva, Matthew R Dent, Longfei Wang, Yijen L. Wu, Elena A. Goncharova, Dmitry A. Goncharov, Mike Reynolds, Yen Chun Lai, Andrea R. Levine, Elizabeth R. Rochon, Delphine Gomez, and Stephen Y. Chan
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Ventricular Dysfunction, Right ,MIRN193 microRNA ,Cardiorespiratory Medicine and Haematology ,030204 cardiovascular system & hematology ,Cardiovascular ,Mitochondria, Heart ,Animals, Genetically Modified ,chemistry.chemical_compound ,Soluble Guanylyl Cyclase ,0302 clinical medicine ,Smooth Muscle ,pulmonary hypertension ,Ventricular Dysfunction ,2.1 Biological and endogenous factors ,nuclear factor Y ,Aetiology ,Metabolic Syndrome ,0303 health sciences ,Diabetes ,Heart ,Pulmonary ,Mitochondria ,Right ,Heart Disease ,Phenotype ,5.1 Pharmaceuticals ,Hypertension ,Public Health and Health Services ,Disease Susceptibility ,Development of treatments and therapeutic interventions ,Cardiology and Cardiovascular Medicine ,Signal Transduction ,Guanylate cyclase ,medicine.medical_specialty ,Physiological ,Hypertension, Pulmonary ,Clinical Sciences ,Myocytes, Smooth Muscle ,Genetically Modified ,Stress ,Article ,Nitric oxide ,03 medical and health sciences ,Downregulation and upregulation ,nitric oxide ,Stress, Physiological ,Physiology (medical) ,Internal medicine ,medicine ,Animals ,Humans ,human ,Obesity ,Exercise ,Nutrition ,030304 developmental biology ,Heart Failure ,Myocytes ,Mir 193b ,Animal ,business.industry ,Stroke Volume ,medicine.disease ,Pulmonary hypertension ,Rats ,Disease Models, Animal ,MicroRNAs ,Endocrinology ,Cardiovascular System & Hematology ,CCAAT-Binding Factor ,Gene Expression Regulation ,chemistry ,Disease Models ,Metabolic syndrome ,Reactive Oxygen Species ,Heart failure with preserved ejection fraction ,business ,Biomarkers - Abstract
Background: Many patients with heart failure with preserved ejection fraction have metabolic syndrome and develop exercise-induced pulmonary hypertension (EIPH). Increases in pulmonary vascular resistance in patients with heart failure with preserved ejection fraction portend a poor prognosis; this phenotype is referred to as combined precapillary and postcapillary pulmonary hypertension (CpcPH). Therapeutic trials for EIPH and CpcPH have been disappointing, suggesting the need for strategies that target upstream mechanisms of disease. This work reports novel rat EIPH models and mechanisms of pulmonary vascular dysfunction centered around the transcriptional repression of the soluble guanylate cyclase (sGC) enzyme in pulmonary artery (PA) smooth muscle cells. Methods: We used obese ZSF-1 leptin-receptor knockout rats (heart failure with preserved ejection fraction model), obese ZSF-1 rats treated with SU5416 to stimulate resting pulmonary hypertension (obese+sugen, CpcPH model), and lean ZSF-1 rats (controls). Right and left ventricular hemodynamics were evaluated using implanted catheters during treadmill exercise. PA function was evaluated with magnetic resonance imaging and myography. Overexpression of nuclear factor Y α subunit (NFYA), a transcriptional enhancer of sGC β1 subunit (sGCβ1), was performed by PA delivery of adeno-associated virus 6. Treatment groups received the SGLT2 inhibitor empagliflozin in drinking water. PA smooth muscle cells from rats and humans were cultured with palmitic acid, glucose, and insulin to induce metabolic stress. Results: Obese rats showed normal resting right ventricular systolic pressures, which significantly increased during exercise, modeling EIPH. Obese+sugen rats showed anatomic PA remodeling and developed elevated right ventricular systolic pressure at rest, which was exacerbated with exercise, modeling CpcPH. Myography and magnetic resonance imaging during dobutamine challenge revealed PA functional impairment of both obese groups. PAs of obese rats produced reactive oxygen species and decreased sGCβ1 expression. Mechanistically, cultured PA smooth muscle cells from obese rats and humans with diabetes or treated with palmitic acid, glucose, and insulin showed increased mitochondrial reactive oxygen species, which enhanced miR-193b–dependent RNA degradation of nuclear factor Y α subunit (NFYA), resulting in decreased sGCβ1-cGMP signaling. Forced NYFA expression by adeno-associated virus 6 delivery increased sGCβ1 levels and improved exercise pulmonary hypertension in obese+sugen rats. Treatment of obese+sugen rats with empagliflozin improved metabolic syndrome, reduced mitochondrial reactive oxygen species and miR-193b levels, restored NFYA/sGC activity, and prevented EIPH. Conclusions: In heart failure with preserved ejection fraction and CpcPH models, metabolic syndrome contributes to pulmonary vascular dysfunction and EIPH through enhanced reactive oxygen species and miR-193b expression, which downregulates NFYA-dependent sGCβ1 expression. Adeno-associated virus–mediated NFYA overexpression and SGLT2 inhibition restore NFYA-sGCβ1-cGMP signaling and ameliorate EIPH.
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- 2021
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25. Common infectious morbidity and white blood cell count in middle childhood predict behavior problems in adolescence
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Henry Oliveros, Kallisse R Dent, Mercedes Mora-Plazas, Sonia L. Robinson, Eduardo Villamor, Constanza Marin, and Rachael J Beer
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Pediatrics ,medicine.medical_specialty ,Incidence (epidemiology) ,Respiratory infection ,CBCL ,Confidence interval ,Psychiatry and Mental health ,Diarrhea ,Cohort ,Developmental and Educational Psychology ,Vomiting ,medicine ,medicine.symptom ,Child Behavior Checklist ,Psychology - Abstract
We examined the associations of middle childhood infectious morbidity and inflammatory biomarkers with adolescent internalizing and externalizing behavior problems. We recruited 1018 Colombian schoolchildren aged 5–12 years into a cohort. We quantified white blood cell (WBC) counts and C-reactive protein at enrollment and prospectively recorded incidence of gastrointestinal, respiratory, and fever-associated morbidity during the first follow-up year. After a median 6 years, we assessed adolescent internalizing and externalizing behavior problems using child behavior checklist (CBCL) and youth self-report (YSR) questionnaires. Behavior problem scores were compared over biomarker and morbidity categories using mean differences and 95% confidence intervals (CI) from multivariable linear regression. Compared with children without symptoms, CBCL internalizing problem scores were an adjusted 2.5 (95% CI: 0.1, 4.9; p = .04) and 3.1 (95% CI: 1.1, 5.2; p = .003) units higher among children with moderate diarrhea with vomiting and high cough with fever rates, respectively. High cough with fever and high fever rates were associated with increased CBCL somatic complaints and anxious/depressed scores, respectively. WBC >10,000/mm3 was associated with both internalizing problem and YSR withdrawn/depressed scores. There were no associations with externalizing behavior problems. Whether or not decreasing the burden of common infections results in improved neurobehavioral outcomes warrants further investigation.
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- 2021
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26. Sirtuin 1 is not required for contraction-stimulated glucose uptake in mouse skeletal muscle
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Shannon N. Bremner, Simon Schenk, Ji H. Kang, Ji E. Park, Stewart W. C. Masson, Jason Dagoon, Jessica R. Dent, and Troy L. Merry
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Male ,0301 basic medicine ,medicine.medical_specialty ,Contraction (grammar) ,Physiology ,Glucose uptake ,030209 endocrinology & metabolism ,Muscle type ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Sirtuin 1 ,Physiology (medical) ,Internal medicine ,medicine ,Animals ,Insulin ,Muscle, Skeletal ,biology ,Chemistry ,Skeletal muscle ,Biological Transport ,Sexual dimorphism ,Glucose ,030104 developmental biology ,Endocrinology ,medicine.anatomical_structure ,biology.protein ,Female ,Ex vivo ,Muscle Contraction ,Research Article - Abstract
While it has long been known that contraction robustly stimulates skeletal muscle glucose uptake, the molecular steps regulating this increase remain incompletely defined. The mammalian ortholog of Sir2, sirtuin 1 (SIRT1), is an NAD(+)-dependent protein deacetylase that is thought to link perturbations in energy flux associated with exercise to subsequent cellular adaptations. Nevertheless, its role in contraction-stimulated glucose uptake has not been described. The objective of this study was to determine the importance of SIRT1 to contraction-stimulated glucose uptake in mouse skeletal muscle. Using a radioactive 2-deoxyglucose uptake (2DOGU) approach, we measured ex vivo glucose uptake in unstimulated (rested) and electrically stimulated (100 Hz contraction every 15 s for 10 min; contracted) extensor digitorum longus (EDL) and soleus from ∼15-wk-old male and female mice with muscle-specific knockout of SIRT1 deacetylase activity and their wild-type littermates. Skeletal muscle force decreased over the contraction protocol, although there were no differences in the rate of fatigue between genotypes. In EDL and soleus, loss of SIRT1 deacetylase activity did not affect contraction-induced increase in glucose uptake in either sex. Interestingly, the absolute rate of contraction-stimulated 2DOGU was ∼1.4-fold higher in female compared with male mice, regardless of muscle type. Taken together, our findings demonstrate that SIRT1 is not required for contraction-stimulated glucose uptake in mouse skeletal muscle. Moreover, to our knowledge, this is the first demonstration of sex-based differences in contraction-stimulated glucose uptake in mouse skeletal muscle. NEW & NOTEWORTHY Here, we demonstrate that glucose uptake in response to ex vivo contractions is not affected by the loss of sirtuin 1 (SIRT1) deacetylase function in muscle, regardless of sex or muscle type. Interestingly, however, similar to studies on insulin-stimulated glucose uptake, we demonstrate that contraction-stimulated glucose uptake is robustly higher in female compared with the male skeletal muscle. To our knowledge, this is the first demonstration of sex-based differences in contraction-stimulated glucose uptake in skeletal muscle.
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- 2021
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27. Is cancer a disease set up by cellular stress responses?
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Myrna A. R. Dent and Armando Aranda-Anzaldo
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0301 basic medicine ,Cellular adaptation ,Disease ,Biology ,medicine.disease_cause ,Biochemistry ,Evolution, Molecular ,Peto's paradox ,03 medical and health sciences ,0302 clinical medicine ,Germline mutation ,Neoplasms ,medicine ,Animals ,Humans ,Epigenetics ,Cancer ,Cell Biology ,medicine.disease ,Adaptation, Physiological ,Phenotype ,Cell Transformation, Neoplastic ,030104 developmental biology ,030220 oncology & carcinogenesis ,Mutation ,Perspective and Reflection Article ,Carcinogenesis ,Neuroscience - Abstract
For several decades, the somatic mutation theory (SMT) has been the dominant paradigm on cancer research, leading to the textbook notion that cancer is fundamentally a genetic disease. However, recent discoveries indicate that mutations, including “oncogenic” ones, are widespread in normal somatic cells, suggesting that mutations may be necessary but not sufficient for cancer to develop. Indeed, a fundamental but as yet unanswered question is whether or not the first step in oncogenesis corresponds to a mutational event. On the other hand, for some time, it has been acknowledged the important role in cancer progression of molecular processes that participate in buffering cellular stress. However, their role is considered secondary or complementary to that of putative oncogenic mutations. Here we present and discuss evidence that cancer may have its origin in epigenetic processes associated with cellular adaptation to stressful conditions, and so it could be a direct consequence of stress-buffering mechanisms that allow cells with aberrant phenotypes (not necessarily associated with genetic mutations) to survive and propagate within the organism. We put forward the hypothesis that there would be an inverse correlation between the activation threshold of the cellular stress responses (CSRs) and the risk of cancer, so that species or individuals with low-threshold CSRs will display a higher incidence or risk of cancer.
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- 2021
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28. Thinking Psychologically About Children Who Are Looked After and Adopted: Space for Reflection
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Kim S. Golding, Helen R. Dent, Ruth Nissim, Liz Stott, Kim S. Golding, Helen R. Dent, Ruth Nissim, Liz Stott
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- 2006
29. Protein‐carbohydrate ingestion alters Vps34 cellular localization independent of changes in kinase activity in human skeletal muscle
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Stewart Jeromson, Jessica R. Dent, Zhe Song, Leigh Breen, Simon W. Jones, Andrew Philp, Nathan Hodson, James Murray, D. Lee Hamilton, Mary F. O’Leary, and Thomas Nicholson
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Adult ,Male ,medicine.medical_specialty ,Physiology ,Muscle Fibers, Skeletal ,Carbohydrates ,P70-S6 Kinase 1 ,mTORC1 ,030204 cardiovascular system & hematology ,Cell Line ,Eating ,Mice ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Physiology (medical) ,Internal medicine ,medicine ,Animals ,Humans ,Kinase activity ,Muscle, Skeletal ,Mechanistic target of rapamycin ,PI3K/AKT/mTOR pathway ,Cellular localization ,Nutrition and Dietetics ,biology ,Myogenesis ,Chemistry ,TOR Serine-Threonine Kinases ,fungi ,Skeletal muscle ,General Medicine ,Middle Aged ,Class III Phosphatidylinositol 3-Kinases ,Endocrinology ,medicine.anatomical_structure ,biology.protein ,030217 neurology & neurosurgery ,Signal Transduction - Abstract
New findings What is the central question of the study? Is Vps34 a nutrient-sensitive activator of mTORC1 in human skeletal muscle? What is the main finding and its importance? We show that altering nutrient availability, via protein-carbohydrate feeding, does not increase Vps34 kinase activity in human skeletal muscle. Instead, feeding increased Vps34-mTORC1 co-localization in parallel to increased mTORC1 activity. These findings may have important implications in the understanding nutrient-induced mTORC1 activation in skeletal muscle via interaction with Vps34. Abstract The Class III PI3Kinase, Vps34, has recently been proposed as a nutrient sensor, essential for activation of the mechanistic target of rapamycin (mTOR) complex 1 (mTORC1). We therefore investigated the effects of increasing nutrient availability through protein-carbohydrate (PRO-CHO) feeding on Vps34 kinase activity and cellular localization in human skeletal muscle. Eight young, healthy males (21 ± 0.5 yrs, 77.7 ± 9.9 kg, 25.9 ± 2.7 kg/m2 , mean ± SD) ingested a PRO-CHO beverage containing 20/44/1 g PRO/CHO/FAT respectively, with skeletal muscle biopsies obtained at baseline and 1 h and 3 h post-feeding. PRO-CHO feeding did not alter Vps34 kinase activity, but did stimulate Vps34 translocation toward the cell periphery (PRE (mean ± SD) - 0.273 ± 0.040, 1 h - 0.348 ± 0.061, Pearson's Coefficient (r)) where it co-localized with mTOR (PRE - 0.312 ± 0.040, 1 h - 0.348 ± 0.069, Pearson's Coefficient (r)). These alterations occurred in parallel to an increase in S6K1 kinase activity (941 ± 466% of PRE at 1 h post-feeding). Subsequent in vitro experiments in C2C12 and human primary myotubes displayed no effect of the Vps34-specific inhibitor SAR405 on mTORC1 signalling responses to elevated nutrient availability. Therefore, in summary, PRO-CHO ingestion does not increase Vps34 activity in human skeletal muscle, whilst pharmacological inhibition of Vps34 does not prevent nutrient stimulation of mTORC1 in vitro. However, PRO-CHO ingestion promotes Vps34 translocation to the cell periphery, enabling Vps34 to associate with mTOR. Therefore, our data suggests that interaction between Vps34 and mTOR, rather than changes in Vps34 activity per se may be involved in PRO-CHO activation of mTORC1 in human skeletal muscle.
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- 2020
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30. Model Complexes Elucidate the Role of the Proximal Hydrogen-Bonding Network in Cytochrome P450s
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Andrew P. Hunt, Matthew R. Dent, Nicolai Lehnert, Michael W. Milbauer, Subhra Samanta, and Judith N. Burstyn
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chemistry.chemical_classification ,Cytochrome ,biology ,010405 organic chemistry ,Chemistry ,Stereochemistry ,Hydrogen bond ,Hydrogen Bonding ,010402 general chemistry ,Ferric Compounds ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,Heme B ,chemistry.chemical_compound ,Enzyme ,Cytochrome P-450 Enzyme System ,Models, Chemical ,biology.protein ,Reactivity (chemistry) ,Sulfhydryl Compounds ,Physical and Theoretical Chemistry ,Density Functional Theory - Abstract
Cytochrome (Cyt) P450s are an important class of enzymes with numerous functions in nature. The unique reactivity of these enzymes relates to their heme b active sites with an axially bound, deprot...
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- 2020
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31. Evaluation of the Recovery Engagement and Coordination for Health–Veterans Enhanced Treatment Suicide Risk Modeling Clinical Program in the Veterans Health Administration
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Bridget B. Matarazzo, John F. McCarthy, Jodie A. Trafton, Claire M. Hannemann, Mark A. Reger, Sara J. Landes, Ira R. Katz, Samantha A. Cooper, Aaron Eagan, Michael Schoenbaum, and Kallisse R. Dent
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Adult ,Male ,Suicide Prevention ,medicine.medical_specialty ,Psychological intervention ,Cohort Studies ,Health care ,medicine ,Humans ,Original Investigation ,Aged ,Veterans ,Psychiatry ,Suicide attempt ,business.industry ,Research ,General Medicine ,Emergency department ,Middle Aged ,Mental health ,United States ,Online Only ,Suicide ,United States Department of Veterans Affairs ,Family medicine ,Cohort ,Female ,Death certificate ,business ,Cohort study ,Program Evaluation - Abstract
Key Points Question Is the Veterans Health Administration Recovery Engagement and Coordination for Health–Veterans Enhanced Treatment (REACH VET) program, which facilitates care enhancements for individuals in the top 0.1% suicide risk tier using a validated algorithm, associated with health care utilization, treatment engagement, suicide attempts, suicide safety plan documentation, and suicide mortality? Findings In this cohort study including 173 313 individuals before and after implementation of the REACH VET program using triple differences, inclusion in the REACH VET program was associated with having more outpatient encounters, increased documentation of new suicide prevention safety plans, and fewer inpatient mental health admissions, emergency department visits, and documented suicide attempts. Meaning These findings suggest that clinical programs using predictive modeling can support care enhancements and risk reduction., This cohort study examines treatment engagement, health care utilization, and suicide-related outcomes associated with the Veterans Health Administration's Recovery Engagement and Coordination for Health–Veterans Enhanced Treatment (REACH VET) suicide risk modeling clinical program., Importance The Veterans Health Administration (VHA) implemented a national clinical program using a suicide risk prediction algorithm, Recovery Engagement and Coordination for Health–Veterans Enhanced Treatment (REACH VET), in which clinicians facilitate care enhancements for individuals identified in local top 0.1% suicide risk tiers. Evaluation studies are needed. Objective To determine associations with treatment engagement, health care utilization, suicide attempts, safety plan documentation, and 6-month mortality. Design, Setting, and Participants This cohort study used triple differences analyses comparing 6-month changes in outcomes after vs before program entry for individuals entering the REACH VET program (March 2017-December 2018) vs a similarly identified top 0.1% suicide risk tier cohort from prior to program initiation (March 2014-December 2015), adjusting for trends across subthreshold cohorts. Subcohort analyses (including individuals from March 2017-June 2018) evaluated difference-in-differences for cause-specific mortality using death certificate data. The subthreshold cohorts included individuals in the top 0.3% to 0.1% suicide risk tier, below the threshold for REACH VET eligibility, from the concurrent REACH VET period and from the pre–REACH VET period. Data were analyzed from December 2019 through September 2021. Exposures REACH VET–designated clinicians treatment reevaluation and outreach for care enhancements, including safety planning, increased monitoring, and interventions to enhance coping. Main Outcomes and Measures Process outcomes included VHA scheduled, completed, and missed appointments; mental health visits; and safety plan documentation and documentation within 6 months for individuals without plans within the prior 2 years. Clinical outcomes included mental health admissions, emergency department visits, nonfatal suicide attempts, and all-cause, suicide, and nonsuicide external-cause mortality. Results A total of 173 313 individuals (mean [SD] age, 51.0 [14.7] years; 161 264 [93.1%] men and 12 049 [7.0%] women) were included in analyses, including 40 816 individuals eligible for REACH VET care and 36 604 individuals from the pre–REACH VET period in the top 0.1% of suicide risk. The REACH VET intervention was associated with significant increases in completed outpatient appointments (adjusted triple difference [ATD], 0.31; 95% CI, 0.06 to 0.55) and proportion of individuals with new safety plans (ATD, 0.08; 95% CI, 0.06 to 0.10) and reductions in mental health admissions (ATD, −0.08; 95% CI, −0.10 to −0.05), emergency department visits (ADT, −0.03; 95% CI, −0.06 to −0.01), and suicide attempts (ADT, −0.05; 95% CI, −0.06 to −0.03). Subcohort analyses did not identify differences in suicide or all-cause mortality (eg, age-and-sex-adjusted difference-in-difference for suicide mortality, 0.0007; 95% CI, −0.0006 to 0.0019). Conclusions and Relevance These findings suggest that REACH VET implementation was associated with greater treatment engagement and new safety plan documentation and fewer mental health admissions, emergency department visits, and suicide attempts. Clinical programs using risk modeling may be effective tools to support care enhancements and risk reduction.
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- 2021
32. A review of the biological and chemical effects of hypolimnetic oxygenation
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Barry C. Moore, Andrew W. Child, Megan M. Skinner, Stephen R. Dent, and Ellen P. Preece
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0106 biological sciences ,010604 marine biology & hydrobiology ,Oxygenation ,010501 environmental sciences ,Aquatic Science ,01 natural sciences ,Zooplankton ,Chemical effects ,Nutrient ,Environmental chemistry ,Phytoplankton ,%22">Fish ,Environmental science ,Hypolimnion ,0105 earth and related environmental sciences ,Water Science and Technology - Abstract
Preece EP, Moore BC, Skinner MM, Child A, Dent S. A review of the biological and chemical effects of hypolimnetic oxygenation. Lake Reserv Manage. 35:229–246. The technology of hypolimnetic oxygena...
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- 2019
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33. Coordinative Dance Programs: A Viable Option For Improving Physical Fitness Among Older Adults
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Shaquitta R. Dent, Rafael A. Alamilla, Robert C. Soliven, Tharon Holt, Navin Kaushal, and NiCole R. Keith
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Physical Therapy, Sports Therapy and Rehabilitation ,Orthopedics and Sports Medicine - Published
- 2022
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34. Comparison Between Dance-based And Traditional Exercise On Health-related Quality Of Life: A Cross-sectional Analysis
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Rafael A. Alamilla, Shaquitta R. Dent, Robert C. Soliven, Tharon Holt, Navin Kaushal, and NiCole R. Keith
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Physical Therapy, Sports Therapy and Rehabilitation ,Orthopedics and Sports Medicine - Published
- 2022
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35. Endogenous Hemoprotein-Dependent Signaling Pathways of Nitric Oxide and Nitrite
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Jesús Tejero, Anthony W. DeMartino, Mark T. Gladwin, and Matthew R Dent
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biology ,Active site ,Nitric Oxide ,Article ,Nitric oxide ,Cell biology ,Inorganic Chemistry ,Nitric oxide synthase ,chemistry.chemical_compound ,chemistry ,Biosynthesis ,biology.protein ,Physical and Theoretical Chemistry ,Signal transduction ,Nitrite ,Soluble guanylyl cyclase ,Heme - Abstract
Interdisciplinary research at the interface of chemistry, physiology, and biomedicine have uncovered pivotal roles of nitric oxide (NO) as a signaling molecule that regulates vascular tone, platelet aggregation, and other pathways relevant to human health and disease. Heme is central to physiological NO signaling, serving as the active site for canonical NO biosynthesis in nitric oxide synthase (NOS) enzymes and as the highly selective NO binding site in the soluble guanylyl cyclase receptor. Outside of the primary NOS-dependent biosynthetic pathway, other hemoproteins, including hemoglobin and myoglobin, generate NO via the reduction of nitrite. This auxiliary hemoprotein reaction unlocks a “second axis” of NO signaling in which nitrite serves as a stable NO reservoir. In this Forum Article, we highlight these NO-dependent physiological pathways and examine complex chemical and biochemical reactions that govern NO and nitrite signaling in vivo. We focus on hemoprotein-dependent reaction pathways that generate and consume NO in the presence of nitrite and consider intermediate nitrogen oxides, including NO(2), N(2)O(3), and S-nitrosothiols, that may facilitate nitrite-based signaling in blood vessels and tissues. We also discuss emergent therapeutic strategies that leverage our understanding of these key reaction pathways to target NO signaling and treat a wide range of diseases.
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- 2021
36. Cell-free and alkylated hemoproteins improve survival in mouse models of carbon monoxide poisoning
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Qinzi Xu, Jason J. Rose, Xiukai Chen, Ling Wang, Anthony W. DeMartino, Matthew R. Dent, Sagarika Tiwari, Kaitlin Bocian, Xueyin N. Huang, Qin Tong, Charles F. McTiernan, Lanping Guo, Elmira Alipour, Trevor C. Jones, K. Burak Ucer, Daniel B. Kim-Shapiro, Jesús Tejero, and Mark T. Gladwin
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Oxygen ,Mice ,Carbon Monoxide Poisoning ,Carbon Monoxide ,Hemoglobins ,Kinetics ,Disease Models, Animal ,Animals ,Humans ,General Medicine ,Horses - Abstract
I.v. administration of a high-affinity carbon monoxide-binding (CO-binding) molecule, recombinant neuroglobin, can improve survival in CO poisoning mouse models. The current study aims to discover how biochemical variables of the scavenger determine the CO removal from the RBCs by evaluating 3 readily available hemoproteins, 2,3-diphosphoglycerate stripped human hemoglobin (StHb); N-ethylmaleimide modified hemoglobin (NEMHb); and equine myoglobin (Mb). These molecules efficiently sequester CO from hemoglobin in erythrocytes in vitro. A kinetic model was developed to predict the CO binding efficacy for hemoproteins, based on their measured in vitro oxygen and CO binding affinities, suggesting that the therapeutic efficacy of hemoproteins for CO poisoning relates to a high M value, which is the binding affinity for CO relative to oxygen (KA,CO/KA,O2). In a lethal CO poisoning mouse model, StHb, NEMHb, and Mb improved survival by 100%, 100%, and 60%, respectively, compared with saline controls and were well tolerated in 48-hour toxicology assessments. In conclusion, both StHb and NEMHb have high CO binding affinities and M values, and they scavenge CO efficiently in vitro and in vivo, highlighting their therapeutic potential for point-of-care antidotal therapy of CO poisoning.
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- 2021
37. β-Catenin is required for optimal exercise- andcontraction-stimulated skeletal muscle glucose uptake
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Caitlin MacRae, Stewart W. C. Masson, Randall F. D'Souza, Jonathan S. T. Woodhead, Sophie C. Broome, Tumanu Futi, Hyun C. Cho, Jessica R. Dent, Robert D. Atiola, Peter R. Shepherd, and Troy L. Merry
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rac1 GTP-Binding Protein ,insulin ,Physiology ,Glucose uptake ,Mice ,medicine ,Myocyte ,Animals ,Muscle, Skeletal ,Actin ,beta Catenin ,Glucose Transporter Type 4 ,biology ,Myogenesis ,Chemistry ,Glucose transporter ,Skeletal muscle ,glucose transport ,Actin cytoskeleton ,Cell biology ,medicine.anatomical_structure ,Cross-Sectional Studies ,Glucose ,biology.protein ,actin ,GLUT4 ,Rac1 ,Muscle Contraction - Abstract
Key points Loss of β-catenin impairs in vivo and isolated muscle exercise/contraction-stimulated glucose uptake. β-Catenin is required for exercise-induced skeletal muscle actin cytoskeleton remodelling. β-Catenin675 phosphorylation during exercise may be intensity dependent. Abstract The conserved structural protein β-catenin is an emerging regulator of vesicle trafficking in multiple tissues and supports insulin-stimulated glucose transporter 4 (GLUT4) translocation in skeletal muscle by facilitating cortical actin remodelling. Actin remodelling may be a convergence point between insulin and exercise/contraction-stimulated glucose uptake. Here we investigated whether β-catenin is involved in regulating exercise/contraction-stimulated glucose uptake. We report that the muscle-specific deletion of β-catenin induced in adult mice (BCAT-mKO) impairs both exercise- and contraction (isolated muscle)-induced glucose uptake without affecting running performance or canonical exercise signalling pathways. Furthermore, high intensity exercise in mice and contraction of myotubes and isolated muscles led to the phosphorylation of β-cateninS675 , and this was impaired by Rac1 inhibition. Moderate intensity exercise in control and Rac1 muscle-specific knockout mice did not induce muscle β-cateninS675 phosphorylation, suggesting exercise intensity-dependent regulation of β-cateninS675 . Introduction of a non-phosphorylatable S675A mutant of β-catenin into myoblasts impaired GLUT4 translocation and actin remodelling stimulated by carbachol, a Rac1 and RhoA activator. Exercise-induced increases in cross-sectional phalloidin staining (F-actin marker) of gastrocnemius muscle was impaired in muscle from BCAT-mKO mice. Collectively our findings suggest that β-catenin is required for optimal glucose transport in muscle during exercise/contraction, potentially via facilitating actin cytoskeleton remodelling.
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- 2021
38. Managing cancer patients during the COVID-19 pandemic:an ESMO multidisciplinary expert consensus
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G. Curigliano, S. Banerjee, A. Cervantes, M.C. Garassino, P. Garrido, N. Girard, J. Haanen, K. Jordan, F. Lordick, J.P. Machiels, O. Michielin, S. Peters, J. Tabernero, J.Y. Douillard, G. Pentheroudakis, A. Addeo, L. Albiges, P.A. Ascierto, F. Barlesi, C. Caldas, F. Cardoso, I.F. Chaberny, N.I. Cherny, T.K. Choueiri, M.L.K. Chua, C. Criscitiello, E. de Azambuja, D. De Ruysscher, E. de Vries, R. Dent, D. D’Ugo, R. Dziadziuszko, C. Faivre-Finn, E. Felip, M. Garassino, R. Glynne-Jones, V. Golfinopoulos, E. Hamilton, P.A. Jänne, R. Kanesvaran, S.B. Kim, U.G. Liebert, T.S.K. Mok, G. Morgan, R. Obermannova, K. Park, A. Passaro, M. Reck, R. Salazar Soler, F. Scotté, S. Senan, C. Sessa, E. Smyth, R. Soo, J.C. Soria, J. Spicer, F. Strasser, D.S.W. Tan, D. Trapani, E. Van Cutsem, H. van Halteren, P.E. van Schil, G. Veronesi, J. Yang, UCL - SSS/IREC/MIRO - Pôle d'imagerie moléculaire, radiothérapie et oncologie, UCL - (SLuc) Unité d'oncologie médicale, UCL - (SLuc) Centre du cancer, UCL - (SLuc) Service d'oto-rhino-laryngologie, Radiation Oncology, and CCA - Cancer Treatment and quality of life
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0301 basic medicine ,medicine.medical_specialty ,Consensus ,Coronavirus disease 2019 (COVID-19) ,Settore MED/18 - CHIRURGIA GENERALE ,Pneumonia, Viral ,education ,Disease ,Medical Oncology ,Real-Time Polymerase Chain Reaction ,Special Article ,03 medical and health sciences ,Betacoronavirus ,0302 clinical medicine ,Multidisciplinary approach ,Neoplasms ,Pandemic ,Granulocyte Colony-Stimulating Factor ,Medicine ,Humans ,Disease management (health) ,Pandemics ,Societies, Medical ,business.industry ,SARS-CoV-2 ,Expert consensus ,COVID-19 ,Disease Management ,covid ,Hematology ,Telemedicine ,Europe ,030104 developmental biology ,Oncology ,030220 oncology & carcinogenesis ,Family medicine ,Cancer management ,Severe acute respiratory syndrome coronavirus ,business ,Coronavirus Infections ,T-Lymphocytes, Cytotoxic - Abstract
We established an international consortium to review and discuss relevant clinical evidence in order to develop expert consensus statements related to cancer management during the severe acute respiratory syndrome coronavirus 2-related disease (COVID-19) pandemic. The steering committee prepared 10 working packages addressing significant clinical questions from diagnosis to surgery. During a virtual consensus meeting of 62 global experts and one patient advocate, led by the European Society for Medical Oncology, statements were discussed, amended and voted upon. When consensus could not be reached, the panel revised statements until a consensus was reached. Overall, the expert panel agreed on 28 consensus statements that can be used to overcome many of the clinical and technical areas of uncertainty ranging from diagnosis to therapeutic planning and treatment during the COVID-19 pandemic.
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- 2020
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39. Mercury removal from municipal secondary effluent with hydrous ferric oxide reactive filtration
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Marc W. Beutel, Remy L. Newcombe, Stephen R. Dent, and Gregory Möller
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chemistry.chemical_element ,02 engineering and technology ,010501 environmental sciences ,engineering.material ,Ferric Compounds ,01 natural sciences ,Water Purification ,Hydrous ferric oxides ,020401 chemical engineering ,Dissolved organic carbon ,Environmental Chemistry ,Total phosphorus ,Cities ,0204 chemical engineering ,Turbidity ,Waste Management and Disposal ,Effluent ,Volume concentration ,0105 earth and related environmental sciences ,Water Science and Technology ,Chemistry ,Ecological Modeling ,Mercury ,Methylmercury Compounds ,Pollution ,Mercury (element) ,Environmental chemistry ,Total hg ,engineering ,Filtration ,Water Pollutants, Chemical - Abstract
This study evaluated the ability of hydrous ferric oxide reactive filtration (HFO-RF) to remove mercury (Hg) from municipal secondary effluent at four study sites. Pilot HFO-RF systems (136 m3 /day) at two sites demonstrated total Hg concentration removal efficiencies of 96% (inflow/outflow mean total Hg: 43.6/1.6 ng/L) and 80% (4.2/0.8 ng/L). A lightly loaded medium-scale HFO-RF system (950 m3 /day) had a concentration removal efficiency of 53% (0.98/0.46 ng/L) and removed 0.52 mg/day of total Hg and 2.2 μg/day of methyl-Hg. A full-scale HFO-RF system (11,400 m3 /day) yielded a total Hg concentration removal efficiency of 97% (87/2.7 ng/L) and removed an estimated 0.36 kg/year of Hg. Results suggest that the quality of secondary effluent, including dissolved organic matter content, affects achievable minimum total Hg concentrations in effluent from HFO-RF systems. Low HFO-RF effluent concentrations (
- Published
- 2019
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40. Postexercise skeletal muscle signaling responses to moderate- to high-intensity steady-state exercise in the fed or fasted state
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Martina Zemp, Henry B. Ogden, Ben Stocks, Jessica R. Dent, and Andrew Philp
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Adult ,Glycerol ,Male ,medicine.medical_specialty ,Physiology ,Endocrinology, Diabetes and Metabolism ,Fatty Acids, Nonesterified ,Protein Serine-Threonine Kinases ,Young Adult ,Oxygen Consumption ,Physiology (medical) ,Internal medicine ,medicine ,Humans ,RNA, Messenger ,Phosphorylation ,Cyclic AMP Response Element-Binding Protein ,Muscle, Skeletal ,Exercise ,chemistry.chemical_classification ,Chemistry ,High intensity ,Adenylate Kinase ,Pyruvate Dehydrogenase Acetyl-Transferring Kinase ,AMPK ,Fatty acid ,Skeletal muscle ,Fasting ,Metabolism ,Postprandial Period ,Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ,Endurance Training ,Endocrinology ,medicine.anatomical_structure ,Fasted state ,Steady state exercise ,Calcium-Calmodulin-Dependent Protein Kinase Type 2 ,Signal Transduction - Abstract
Exercise performed in the fasted state acutely increases fatty acid availability and utilization. Furthermore, activation of energy-sensing pathways and fatty acid metabolic genes can be augmented by fasting and fasted exercise. However, whether a similar effect occurs at higher exercise intensities remains poorly understood. This study aimed to assess the effect of fed and fasted exercise upon postexercise signaling and mRNA responses during moderate- to high-intensity steady-state exercise. Eight male participants [age: 25 (SD 2) yr, V̇o2peak: 47.9 (SD 3.8) ml·kg−1·min−1] performed 1 h of cycling at 70% Wmaxin the fasted (FAST) state or 2 h following ingestion of a carbohydrate-rich mixed-macronutrient breakfast (FED). Muscle biopsies were collected pre-, immediately, and 3 h postexercise from the medial vastus lateralis, while venous blood samples were collected throughout the trial. Plasma, nonesterified fatty acid, and glycerol concentrations were elevated during FAST compared with FED, although substrate utilization during exercise was similar. AMPKThr172phosphorylation was ~2.5-fold elevated postexercise in both trials and was significantly augmented by ~30% during FAST. CREBSer133phosphorylation was elevated approximately twofold during FAST, although CREBSer133phosphorylation acutely decreased by ~50% immediately postexercise. mRNA expression of PDK4 was approximately three- to fourfold augmented by exercise and approximately twofold elevated throughout FAST, while expression of PPARGC1A mRNA was similarly activated (~10-fold) by exercise in both FED and FAST. In summary, performing moderate- to high-intensity steady-state exercise in the fasted state increases systemic lipid availability, elevates phosphorylation of AMPKThr172and CREBSer133, and augments PDK4 mRNA expression without corresponding increases in whole body fat oxidation and the mRNA expression of PPARGC1A.
- Published
- 2019
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41. N-Myc and GCN5 regulate significantly overlapping transcriptional programs in neural stem cells.
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Verónica Martínez-Cerdeño, Jessica M Lemen, Vanessa Chan, Alice Wey, Wenchu Lin, Sharon R Dent, and Paul S Knoepfler
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Medicine ,Science - Abstract
Here we examine the functions of the Myc cofactor and histone acetyltransferase, GCN5/KAT2A, in neural stem and precursor cells (NSC) using a conditional knockout approach driven by nestin-cre. Mice with GCN5-deficient NSC exhibit a 25% reduction in brain mass with a microcephaly phenotype similar to that observed in nestin-cre driven knockouts of c- or N-myc. In addition, the loss of GCN5 inhibits precursor cell proliferation and reduces their populations in vivo, as does loss of N-myc. Gene expression analysis indicates that about one-sixth of genes whose expression is affected by loss of GCN5 are also affected in the same manner by loss of N-myc. These findings strongly support the notion that GCN5 protein is a key N-Myc transcriptional cofactor in NSC, but are also consistent with recruitment of GCN5 by other transcription factors and the use by N-Myc of other histone acetyltransferases. Putative N-Myc/GCN5 coregulated transcriptional pathways include cell metabolism, cell cycle, chromatin, and neuron projection morphogenesis genes. GCN5 is also required for maintenance of histone acetylation both at its putative specific target genes and at Myc targets. Thus, we have defined an important role for GCN5 in NSC and provided evidence that GCN5 is an important Myc transcriptional cofactor in vivo.
- Published
- 2012
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42. Landscaping the epigenetic landscape of cancer
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Armando Aranda-Anzaldo and Myrna A. R. Dent
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0301 basic medicine ,Value (ethics) ,Cognitive science ,Aging ,Metaphor ,media_common.quotation_subject ,Perspective (graphical) ,Biophysics ,Analogy ,Morphogenetic field ,Epigenesis, Genetic ,Causes of cancer ,03 medical and health sciences ,Phenotype ,030104 developmental biology ,Neoplasms ,Phenomenon ,Animals ,Humans ,Epigenetics ,Molecular Biology ,media_common - Abstract
Waddington's epigenetic landscape was introduced in biology for understanding the complex process of metazoan development in an accessible fashion. The epigenetic landscape concept implies the coupling of cell differentiation and tissue/organ morphogenesis under a simple visual metaphor or analogy with significant heuristic value. Yet in recent times the epigenetic landscape has been reduced to an illustration device just for cell differentiation thus diminishing its explanatory power and heuristic value. On the other hand, the current mainstream in cancer research is concentrated on the search for proximate causes but not on achieving a deeper understanding of the phenomenon. Nevertheless an emerging alternative perspective that understands cancer as a problem related to tissue/organ morphology and structural organization is getting wider attention. Within such a perspective here we present and discuss a historically restored, non-reductionist, version of the epigenetic landscape that when applied to the problem of cancer improves our understanding of it as a common biological phenomenon resulting from the uncoupling of morphogenesis and cell differentiation as a consequence of the progressive erosion of the epigenetic landscape. The following discussion aims at finding a general framework, not dependent on proximate causes, for understanding the phenomenon of cancer and suggests new research strategies on this problem but away from the current emphasis on the putative genetic causes of cancer.
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- 2018
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43. A novel histochemical method of simultaneous detection by a single- or double-immunofluorescence and Bielschowsky’s silver staining in teased rat sciatic nerves
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Rommel Flores-Miranda, Edith Segura-Anaya, Alejandro Martínez-Gómez, and Myrna A. R. Dent
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0301 basic medicine ,Silver Staining ,Pathology ,medicine.medical_specialty ,Fluorescent Antibody Technique ,Schwann cell ,Nerve Fibers, Myelinated ,Silver stain ,03 medical and health sciences ,Myelin ,0302 clinical medicine ,Neurofilament Proteins ,Compact myelin ,Glial Fibrillary Acidic Protein ,medicine ,Animals ,Aquaporin 1 ,Silver Staining Method ,Chemistry ,General Neuroscience ,Myelin Basic Protein ,medicine.disease ,Sciatic Nerve ,Rats ,Staining ,030104 developmental biology ,medicine.anatomical_structure ,Peripheral neuropathy ,nervous system ,Peripheral nervous system ,030217 neurology & neurosurgery - Abstract
Background The Golgi silver method has been widely used in neuroscience for the study of normal and pathological morphology of neurons. The method has been steadily improved and Bielschowsky’s silver staining method (BSSM) is widely used in various pathological conditions, like Alzheimer’s disease. New method In this work, teased sciatic nerves were silver impregnated using BSSM. We also developed simultaneous staining by silver impregnation and single- or double-immunofluorescence of the same section in teased nerve preparations. We immunostained against non-myelinating Schwann cells and different myelinating Schwann cell domains. Results BSSM teased nerves show a strong staining of axons (black) and a gold-brown staining of myelinating and non-myelinating Schwann cells. We were also able to stain by immunofluorescence these BSSM teased nerves with specific molecular markers against non-myelinating Schwann cells, also against non-compact myelin such as the Schmidt-Lanterman incisures or paranodal regions and compact myelin, but not axons. Comparison with existing methods and conclusions In peripheral nerves, several silver impregnation methods have been used to stain nerves in paraffin sections, but not in teased nerves to enable the assessment of isolated nerve fibers. In conclusion, BSSM gives accurate information of nerve morphology and combining the procedure with immunofluorescence it would be very useful to study the molecular nerve domain organization of the nerve fibers, and to study the molecular pathology of axon degeneration, or myelin disorders, or of any peripheral neuropathy, also to study demyelination diseases in the central nervous system.
- Published
- 2018
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44. Continued stabilization of the nuclear higher-order structure of post-mitotic neurons in vivo.
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Janeth Alva-Medina, Apolinar Maya-Mendoza, Myrna A R Dent, and Armando Aranda-Anzaldo
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Medicine ,Science - Abstract
BACKGROUND: Cellular terminal differentiation (TD) correlates with a permanent exit from the cell cycle and so TD cells become stably post-mitotic. However, TD cells express the molecular machinery necessary for cell proliferation that can be reactivated by experimental manipulation, yet it has not been reported the stable proliferation of any type of reactivated TD cells. Neurons become post-mitotic after leaving the ventricular zone. When neurons are forced to reenter the cell cycle they invariably undergo cell death. Wider evidence indicates that the post-mitotic state cannot solely depend on gene products acting in trans, otherwise mutations in the corresponding genes may lead to reentry and completion of the cell cycle in TD cells, but this has not been observed. In the interphase, nuclear DNA of metazoan cells is organized in supercoiled loops anchored to a nuclear nuclear matrix (NM). The DNA-NM interactions define a higher-order structure in the cell nucleus (NHOS). We have previously compared the NHOS of aged rat hepatocytes with that of early post-mitotic rat neurons and our results indicated that a very stable NHOS is a common feature of both senescent and post-mitotic cells in vivo. PRINCIPAL FINDINGS: In the present work we compared the NHOS in rat neurons from different post-natal ages. Our results show that the trend towards further stabilization of the NHOS in neurons continues throughout post-natal life. This phenomenon occurs in absence of overt changes in the post-mitotic state and transcriptional activity of neurons, suggesting that it is independent of functional constraints. CONCLUSIONS: Apparently the continued stabilization of the NHOS as a function of time is basically determined by thermodynamic and structural constraints. We discuss how the resulting highly stable NHOS of neurons may be the structural, non-genetic basis of their permanent and irreversible post-mitotic state.
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- 2011
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45. ¿Si tan sólo se le cambiara de etiqueta a la ciencia?
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Myrna A. R. Dent
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Science ,Social Sciences - Published
- 2007
46. Hemoglobin Variants Influence Plasmodium Falciparum Sexual Differentiation
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Solomon F. Ofori-Acquah, Matthew R Dent, Bethany Flage, and Jesús Tejero
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Genetics ,Sexual differentiation ,biology ,Immunology ,Hemoglobin variants ,Plasmodium falciparum ,Cell Biology ,Hematology ,biology.organism_classification ,Biochemistry - Abstract
It has long been recognized that individuals who express variations of the hemoglobin-A (HbA) protein experience less severe malaria disease. As malaria remains to be one of the most significant infectious diseases in history, this human adaptation has led to the persistence of HbA variants (HbVARs) in the population. The intricate lifecycle of the parasite which causes the most cases of clinical malaria, Plasmodium falciparum, relies on both asexual and sexual reproductive cycles, with host to vector transmission reliant on sexual stage gametocyte formation. Multiple epidemiological studies have shown that HbVARs may influence gametocyte production during P. falciparum infection, with greater gametocyte numbers reported in individuals with hemoglobin variant containing erythrocytes (Hb VAR-Ery) when compared to hemoglobin A containing erythrocytes (Hb A-Ery). Here we provide experimental support for these studies by showing significantly higher sexual differentiation rates among parasites grown in Hb S containing erythrocytes (Hb S-Ery) obtained from sickle cell patients than those differentiated in Hb A-Ery (p=0.038). Because the digestion of hemoglobin is such an integral part of the intraerythrocytic cycle, we then sought to determine whether there was a difference between the hydrolysis efficiencies of HbA and other hemoglobin variants (HbVAR). By using a prominent recombinant P. falciparum hemoglobinase we found the hydrolysis efficiency of HbA to be significantly (p=0.0058) more efficient after 24 hours compared to a HbVAR sample containing mixed amounts of HbA, HbF, and HbS. To further determine whether there is a link between hemoglobin digestion efficiency and sexual differentiation, we therapeutically inhibited the hemoglobin digestion and hemozoin formation process in a culture of P. falciparum using sub-optimal doses of chloroquine diphosphate. We found a significant difference (p Disclosures No relevant conflicts of interest to declare.
- Published
- 2021
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47. Protein-carbohydrate ingestion alters Vps34 cellular localization independent of changes in kinase activity in human skeletal muscle
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Nathan Hodson, David L. Hamilton, Leigh Breen, Zhe Song, James Murray, Jessica R. Dent, Mary F. O’Leary, Stewart Jeromson, Andrew Philp, Thomas Nicholson, and Simon W. Jones
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medicine.medical_specialty ,biology ,Chemistry ,Myogenesis ,fungi ,Skeletal muscle ,P70-S6 Kinase 1 ,mTORC1 ,medicine.anatomical_structure ,Endocrinology ,Internal medicine ,biology.protein ,medicine ,Kinase activity ,Mechanistic target of rapamycin ,PI3K/AKT/mTOR pathway ,Cellular localization - Abstract
The mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) regulates cell size and growth in response to nutrients, however, the mechanisms by which nutrient levels are sensed by mTORC1 in human skeletal muscle are yet to be fully elucidated. The Class III PI3Kinase Vps34 has recently been proposed as a sensor essential for mTORC1 activation following nutrient stimulation. We therefore investigated the effects of increasing nutrient availability through protein-carbohydrate (PRO-CHO) feeding on Vps34 kinase activity and cellular localization in human skeletal muscle. Eight young, healthy males (age – 21 ± 0.5yrs, mean ± SEM) ingested a PRO-CHO beverage containing 20/44/1g PRO/CHO/FAT respectively, with skeletal muscle biopsies obtained at baseline and 1h and 3h post-feeding. PRO-CHO feeding did not alter Vps34 kinase activity, but did stimulate Vps34 translocation toward the cell periphery (PRE (mean±SEM) - 0.273±0.021, 1h - 0.347±0.022, Pearson’s Coefficient (r)) where it co-localized with mTOR (PRE – 0.312±0.018, 1h – 0.348±0.024, Pearson’s Coefficient (r))). These alterations occurred in parallel to an increase in S6K1 kinase activity – 941±164% of PRE at 1h post-feeding). Subsequent in vitro experiments in C2C12 and human primary myotubes displayed no effect of the Vps34-specific inhibitor SAR405 on mTORC1 signalling responses to elevated nutrient availability. Therefore, in summary, PRO-CHO ingestion does not increase Vps34 activity in human skeletal muscle, whilst pharmacological inhibition of Vps34 does not prevent nutrient stimulation of mTORC1 in vitro. However, PRO-CHO ingestion promotes Vps34 translocation to the cell periphery, enabling Vps34 to associate with mTOR. Therefore, our data suggests that interaction between Vps34 and mTOR, rather than changes in Vps34 activity per se may be involved in PRO-CHO activation of mTORC1 in human skeletal muscle.
- Published
- 2020
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48. Precision Oncology vs Phenotypic Approaches in the Management of Cancer: A Case for the Postmitotic State
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Myrna A. R. Dent and Armando Aranda-Anzaldo
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Cellular differentiation ,Aneuploidy ,Cancer ,Biology ,medicine.disease ,medicine.disease_cause ,Phenotype ,Cell nucleus ,medicine.anatomical_structure ,Precision oncology ,medicine ,Cancer research ,Carcinogenesis ,Mitosis - Abstract
The Precision Oncology (PO) approach uses data from next-generation genome sequencing of tumors to select therapy for oncologic patients independently of the type of cancer. PO therapy is designed to inhibit the effects of putative oncogenic mutations that supposedly drive tumorigenesis, but this approach has only improved the clinical outcomes of a picked minority of patients, as PO-based treatments almost universally fail to eradicate the tumor that usually recurs in the short term and in a more malignant fashion. Indeed, the traditional goal in cancer chemotherapy has been the killing of the tumor cells. However, an alternative for cancer therapy is “induced tumor dormancy” which aims at prolonging the survival of patients together with preserving a good quality of life. It is well known that cancer may only arise in cells endowed with a proliferating potential and so that terminally differentiated, postmitotic cells cannot become cancerous. Here we discuss the evidence that the postmitotic state do not depends on genetic factors but it is a consequence of a natural process driven by thermodynamic constraints that results in a high structural stability within the cell nucleus. Such stability becomes an insurmountable energy barrier for karyokinesis and mitosis. We also discuss the evidence that it is possible to induce a postmitotic state in cancerous cells as an alternative approach for achieving tumor dormancy.
- Published
- 2020
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49. The fundamental mechanism of laser-induced damage in optical components for ultrashort-pulse laser systems
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Haojie Huang, T. Z. Kosc, A. A. Kozlov, T. J. Kessler, Kyle Kafka, John C. Lambropoulos, James B. Oliver, Nannan Liu, Alexander A. Shestopalov, Amy L. Rigatti, Stavros G. Demos, Brittany N. Hoffman, and R. Dent
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Materials science ,Laser damage ,Mechanism (biology) ,law ,business.industry ,Atomic force microscopy ,Optoelectronics ,Laser ,business ,law.invention ,Ultrashort pulse laser - Abstract
Laser-induced damage remains a key limiting factor for laser system performance. This presentation will review three main issues associated with laser-induced damage: (1) The processes involved leading to material modification, (2) the damage-initiation mechanisms, and (3) the management of laser damage.
- Published
- 2020
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50. Daño y reparación del sistema nervioso
- Author
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Myrna A. R. Dent
- Subjects
Science ,Social Sciences - Abstract
Se presenta un análisis referente al proceso de regeneración de células en el sistema nervioso periférico (SNP), tanto en vertebrados inferiores como en mamíferos adultos; se resaltan los factores de crecimiento de los axones.
- Published
- 2003
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