495 results on '"Walker, Brian"'
Search Results
2. Assessment of nutrient amendments on stony coral tissue loss disease in Southeast Florida.
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Carreiro, Ashley M., Eckert, Ryan J., Sturm, Alexis B., Ingalls, Thomas C., Combs, Ian R., Walker, Brian K., and Voss, Joshua D.
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SCLERACTINIA ,CORAL diseases ,CORAL colonies ,CORALS ,CORAL communities ,CORAL reefs & islands - Abstract
Florida's coral reefs are facing a multi-year outbreak of stony coral tissue loss disease (SCTLD) with dramatic consequences for coral communities. However, potential anthropogenic and environmental drivers of SCTLD progression and severity remain poorly understood. This study was designed to determine the potential impacts of nutrient amendments on the progression and spread of SCTLD on reefs in Southeast Florida. In situ fertilizer amendments with 30 g of Osmocote™ slow-release fertilizer were used to mimic the effects of agricultural and urban runoff. Fifteen healthy and thirty SCTLD-affected Montastraea cavernosa coral colonies were tagged and divided into three experimental groups: apparently healthy colonies, SCTLD-affected nutrient-amended colonies, and SCTLD-affected control colonies. SCTLD lesion progression, coral tissue loss, and disease prevalence were tracked over a 30-day nutrient amendment period and for an additional 40 days after nutrient amendment removal to determine if there were any latent or recovery effects. Coral tissue loss was tracked over time using Structure-from-Motion photogrammetry and disease prevalence was recorded from diver surveys within a 3-m radius surrounding five centroid colonies from each experimental group. Throughout the experiment, temperature, nutrient concentrations, and SCTLD status of the coral colonies were also monitored. Ultimately, we observed no significant differences in SCTLD progression or surrounding SCTLD prevalence between the nutrient-amended and control groups, suggesting that nutrient amendment had no effect on SCTLD severity during this experiment in Southeast Florida. [ABSTRACT FROM AUTHOR]
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- 2024
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3. ATP-binding cassette family C member 1 constrains metabolic responses to high-fat diet in male mice.
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Villalobos, Elisa, Miguelez-Crespo, Allende, Morgan, Ruth A., Ivatt, Lisa, Paul, Mhairi, Simpson, Joanna P., Homer, Natalie Z. M., Kurian, Dominic, Aguilar, Judit, Kline, Rachel A., Wishart, Thomas M., Morton, Nicholas M., Stimson, Roland H., Andrew, Ruth, Walker, Brian R., and Nixon, Mark
- Abstract
Glucocorticoids modulate glucose homeostasis, acting on metabolically active tissues such as liver, skeletal muscle, and adipose tissue. Intracellular regulation of glucocorticoid action in adipose tissue impacts metabolic responses to obesity. ATP-binding cassette family C member 1 (ABCC1) is a transmembrane glucocorticoid transporter known to limit the accumulation of exogenously administered corticosterone in adipose tissue. However, the role of ABCC1 in the regulation of endogenous glucocorticoid action and its impact on fuel metabolism has not been studied. Here, we investigate the impact of Abcc1 deficiency on glucocorticoid action and high-fat-diet (HFD)-induced obesity. In lean male mice, deficiency of Abcc1 increased endogenous corticosterone levels in skeletal muscle and adipose tissue but did not impact insulin sensitivity. In contrast, Abcc1-deficient male mice on HFD displayed impaired glucose and insulin tolerance, and fasting hyperinsulinaemia, without alterations in tissue corticosterone levels. Proteomics and bulk RNA sequencing revealed that Abcc1 deficiency amplified the transcriptional response to an obesogenic diet in adipose tissue but not in skeletal muscle. Moreover, Abcc1 deficiency impairs key signalling pathways related to glucose metabolism in both skeletal muscle and adipose tissue, in particular those related to OXPHOS machinery and Glut4. Together, our results highlight a role for ABCC1 in regulating glucose homeostasis, demonstrating diet-dependent effects that are not associated with altered tissue glucocorticoid concentrations. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Southeast Florida large Orbicella faveolata are highly fecund without evident disease intervention effects.
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Renegar, D. Abigail, Noren, Hunter K. G., Turner, Nicholas R., Figueiredo, Joana, and Walker, Brian K.
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SCLERACTINIA ,FISH spawning ,REPRODUCTIVE technology ,CORAL reefs & islands ,CORALS ,GAMETES - Abstract
The recentwidespread mortality and tissue loss in Florida from stony coral tissue loss disease (SCTLD) has propelled the need for assisted reproduction to restore reefs, especially for the ESA listed species Orbicella faveolata. In situ gamete collection can be challenging due to the weather and resources (boats and divers) required during the expected spawning window. In the northern portion of the Florida coral reef tract, coral spawn collection has been even more difficult due to historical inconsistency in annual spawning times and the potential for "zombie" corals, i.e. large but reproductively senescent individuals. Therefore, we examined the current reproductive potential of seven large (>2mdiameter) O. faveolata colonies from this region, quantified their fecundity, and estimated the spawning timeframe using histology. Additionally, we explored whether previous SCTLD lesion amoxycillin treatments affected reproductive metrics. Understanding the reproductive capacity and spawning timing of these large corals, given their history of disease and disease treatment, is critical to evaluate potential impacts of SCTLD treatments and the success of assisted reproduction efforts. The histological analysis coupled with inwater observations indicated a probable split-spawn in these individuals in 2020, although the dates of spawning may not be consistent with predictions for the wider Caribbean or with other colonies in Miami and the Florida Keys. All seven large O. faveolata colonies were found to contain abundant oocytes, with no obvious impact of SCTLD treatments on gamete development or fecundity. [ABSTRACT FROM AUTHOR]
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- 2024
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5. 1q amplification and PHF19 expressing high-risk cells are associated with relapsed/refractory multiple myeloma.
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Johnson, Travis S., Sudha, Parvathi, Liu, Enze, Becker, Nathan, Robertson, Sylvia, Blaney, Patrick, Morgan, Gareth, Chopra, Vivek S., Dos Santos, Cedric, Nixon, Michael, Huang, Kun, Suvannasankha, Attaya, Zaid, Mohammad Abu, Abonour, Rafat, and Walker, Brian A.
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MULTIPLE myeloma ,CELL cycle regulation ,WHOLE genome sequencing ,GENE amplification ,PLASMA cells ,CELL cycle - Abstract
Multiple Myeloma is an incurable plasma cell malignancy with a poor survival rate that is usually treated with immunomodulatory drugs (iMiDs) and proteosome inhibitors (PIs). The malignant plasma cells quickly become resistant to these agents causing relapse and uncontrolled growth of resistant clones. From whole genome sequencing (WGS) and RNA sequencing (RNA-seq) studies, different high-risk translocation, copy number, mutational, and transcriptional markers can be identified. One of these markers, PHF19, epigenetically regulates cell cycle and other processes and is already studied using RNA-seq. In this study, we generate a large (325,025 cells and 49 patients) single cell multi-omic dataset and jointly quantify ATAC- and RNA-seq for each cell and matched genomic profiles for each patient. We identify an association between one plasma cell subtype with myeloma progression that we call relapsed/refractory plasma cells (RRPCs). These cells are associated with chromosome 1q alterations, TP53 mutations, and higher expression of PHF19. We also identify downstream regulation of cell cycle inhibitors in these cells, possible regulation by the transcription factor (TF) PBX1 on chromosome 1q, and determine that PHF19 may be acting primarily through this subset of cells. Translocations and copy number variations that affect multiple myeloma (MM) have not been investigated at the single cell level. Here, single cell multi-omics reveal the relationship between epigenetic regulation and cytogenetic events that lead to the increase of cell proliferation in MM. [ABSTRACT FROM AUTHOR]
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- 2024
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6. 5α‐Tetrahydrocorticosterone: A topical anti‐inflammatory glucocorticoid with an improved therapeutic index in a murine model of dermatitis.
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Livingstone, Dawn Elizabeth Watson, Sooy, Karen, Sykes, Catherine, Webster, Scott Peter, Walker, Brian Robert, and Andrew, Ruth
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TOPICAL drug administration ,GLUCOCORTICOIDS ,ORAL drug administration ,SKIN inflammation ,WEIGHT loss ,ANTI-inflammatory agents - Abstract
Background and Purpose: Glucocorticoids are powerful anti‐inflammatory drugs, but are associated with many side‐effects. Topical application in atopic dermatitis leads to skin thinning, metabolic changes, and adrenal suppression. 5α‐Tetrahydrocorticosterone (5αTHB) is a potential selective anti‐inflammatory with reduced metabolic effects. Here, the efficacy and side‐effect profile of 5αTHB were compared with hydrocortisone in preclinical models of irritant dermatitis. Experimental Approach: Acute irritant dermatitis was invoked in ear skin of male C57BL/6 mice with a single topical application of croton oil. Inflammation was assessed as oedema via ear weight following treatment with 5αTHB and hydrocortisone. Side‐effects of 5αTHB and hydrocortisone were assessed following chronic topical steroid treatment (28 days) to non‐irritated skin. Skin thinning was quantified longitudinally by caliper measurements and summarily by qPCR for transcripts for genes involved in extracellular matrix homeostasis; systemic effects of topical steroid administration also were assessed. Clearance of 5αTHB and hydrocortisone were measured following intravenous and oral administration. Key Results: 5αTHB suppressed ear swelling in mice, with ED50 similar to hydrocortisone (23 μg vs. 13 μg). Chronic application of 5αTHB did not cause skin thinning, adrenal atrophy, weight loss, thymic involution, or raised insulin levels, all of which were observed with topical hydrocortisone. Transcripts for genes involved in collagen synthesis and stability were adversely affected by all doses of hydrocortisone, but only by the highest dose of 5αTHB (8× ED50). 5αTHB was rapidly cleared from the systemic circulation. Conclusions and Implications: Topical 5αTHB has potential to treat inflammatory skin conditions, particularly in areas of delicate skin. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Plasma steroid concentrations reflect acute disease severity and normalise during recovery in people hospitalised with COVID‐19.
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Devine, Kerri, Russell, Clark D., Blanco, Giovanny R., Walker, Brian R., Homer, Natalie Z. M., Denham, Scott G., Simpson, Joanna P., Leavy, Olivia C., Elneima, Omer, McAuley, Hamish J. C., Shikotra, Aarti, Singapuri, Amisha, Sereno, Marco, Saunders, Ruth M., Harris, Victoria C., Houchen‐Wolloff, Linzy, Greening, Neil J., Lone, Nazir I., Thorpe, Mathew, and Greenhalf, William
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ADRENAL insufficiency ,POST-acute COVID-19 syndrome ,COVID-19 pandemic ,ACUTE diseases ,COVID-19 ,EMERGING infectious diseases - Abstract
Objective: Endocrine systems are disrupted in acute illness, and symptoms reported following coronavirus disease 2019 (COVID‐19) are similar to those found with clinical hormone deficiencies. We hypothesised that people with severe acute COVID‐19 and with post‐COVID symptoms have glucocorticoid and sex hormone deficiencies. Design/Patients: Samples were obtained for analysis from two UK multicentre cohorts during hospitalisation with COVID‐19 (International Severe Acute Respiratory Infection Consortium/World Health Organisation [WHO] Clinical Characterization Protocol for Severe Emerging Infections in the UK study), and at follow‐up 5 months after hospitalisation (Post‐hospitalisation COVID‐19 study). Measurements: Plasma steroids were quantified by liquid chromatography–mass spectrometry. Steroid concentrations were compared against disease severity (WHO ordinal scale) and validated symptom scores. Data are presented as geometric mean (SD). Results: In the acute cohort (n = 239, 66.5% male), plasma cortisol concentration increased with disease severity (cortisol 753.3 [1.6] vs. 429.2 [1.7] nmol/L in fatal vs. least severe, p <.001). In males, testosterone concentrations decreased with severity (testosterone 1.2 [2.2] vs. 6.9 [1.9] nmol/L in fatal vs. least severe, p <.001). In the follow‐up cohort (n = 198, 62.1% male, 68.9% ongoing symptoms, 165 [121–192] days postdischarge), plasma cortisol concentrations (275.6 [1.5] nmol/L) did not differ with in‐hospital severity, perception of recovery, or patient‐reported symptoms. Male testosterone concentrations (12.6 [1.5] nmol/L) were not related to in‐hospital severity, perception of recovery or symptom scores. Conclusions: Circulating glucocorticoids in patients hospitalised with COVID‐19 reflect acute illness, with a marked rise in cortisol and fall in male testosterone. These findings are not observed 5 months from discharge. The lack of association between hormone concentrations and common post‐COVID symptoms suggests steroid insufficiency does not play a causal role in this condition. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Malignant spinal cord compression: Atypical presentation, false localizing signs, time course, and implications for the emergency physician.
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Georgiou, Anastasios, Farmer, Adam, Georgiou, Loukas, and Walker, Brian
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ABDOMINAL pain ,SPINAL cord compression ,RETROSPECTIVE studies ,DESCRIPTIVE statistics ,ROUTINE diagnostic tests ,MEDICAL records ,ACQUISITION of data ,DELAYED diagnosis ,SYMPTOMS - Abstract
The article focuses on the diagnostic challenges of malignant spinal cord compression (MSCC) in emergency settings. Topics include the prevalence and typical presentation of MSCC, issues with false localizing signs and diagnostic imaging, and the rapid progression of symptoms leading to delays in diagnosis and treatment.
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- 2024
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9. Algal symbiont genera but not coral host genotypes correlate to stony coral tissue loss disease susceptibility among Orbicella faveolata colonies in South Florida.
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Klein, Allison M., Sturm, Alexis B., Eckert, Ryan J., Walker, Brian K., Neely, Karen L., and Voss, Joshua D.
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SCLERACTINIA ,ALGAL communities ,CORAL bleaching ,DISEASE susceptibility ,SINGLE nucleotide polymorphisms ,CORALS ,CORAL reefs & islands - Abstract
Stony coral tissue loss disease (SCTLD) has spread throughout the entirety of Florida's Coral Reef (FCR) and across the Caribbean, impacting at least 30 coral species. The threatened hermatypic coral, Orbicella faveolata, demonstrates intraspecific variation in SCTLD affectedness with some colonies experiencing chronic disease lesions, while other nearby O. faveolata colonies appear unaffected with no disease signs over long monitoring periods. This study evaluated potential genotypic underpinnings of variable disease responses to SCTLD by monitoring and sampling 90 O. faveolata colonies from southeast Florida and the lower Florida Keys. High resolution analyses of >11,000 single nucleotide polymorphisms (SNPs) generated from 2bRAD sequencing indicated there were no SNP loci or genetic lineages significantly associated with O. faveolata SCTLD affectedness. Genotypic differences may still contribute to SCTLD susceptibility; however, these differences were not captured using this reduced representation sequencing approach. Algal symbiont community structure characterized from 2bRAD data revealed that the presence of Durusdinium spp. corresponded with SCTLD-affected colonies as compared to unaffected colonies, suggesting that algal symbiont community make-up may play some role in SCTLD resistance. Data generated by this study will be combined with complementary molecular and physiological approaches to further investigate the complex drivers of intraspecific SCTLD susceptibility and resilience. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Broadscale coral disease interventions elicit efficiencies in endemic disease response.
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Toth, Kathryn A., Buckley, Samantha F., Noren, Hunter, Neely, Karen L., and Walker, Brian K.
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CORAL diseases ,CORALS ,ENDEMIC diseases ,CORAL reefs & islands ,SCLERACTINIA ,CORAL bleaching ,DISEASE prevalence - Abstract
The presence and abundance of reef-building corals are crucial to the long-term existence of Caribbean coral reef ecosystems, providing both direct and indirect, local and global, ecological, economic, and social benefits. In 2014, stony coral tissue loss disease (SCTLD) was first identified in southeast Florida and remains endemic to the region, while continuing to spread throughout the Caribbean. Effective in situ intervention treatments using antibiotic paste can halt lesion progression on Montastraea cavernosa up to 90% of the time. This study investigated intervention activities over a three-year period to identify efficiencies in disease response. Since May 2019, 1,037 corals, >85% of which were M. cavernosa, were treated during disease intervention dives in southeast Florida. Treated coral density, the number of treated corals per meter along a dive track, was significantly higher in the first year compared to subsequent years and displayed annual peaks in late summer each year. Season significantly influenced treatment density, leading to higher values in the wet season across all years, 2019 to 2022. Areas of highest treatment density were identified between Haulover Inlet and Government Cut near Miami and Hillsboro Inlet in northern Broward County. Areas with the highest treatment density were only identified in the first year, suggesting that broadscale interventions may have decreased disease prevalence in subsequent years. Results indicate that in endemic areas with sporadic and dynamic disease prevalence, intervention efforts should be weighted proportionally across space and time to maximize intervention efficiency. This study provides optimistic results for the potential of interventions reducing disease prevalence and supports that disease interventions are an effective coral restoration tool that can decrease the increasing burden on post hoc coral restoration. [ABSTRACT FROM AUTHOR]
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- 2024
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11. Broadscale coral disease interventions elicit efficiencies in endemic disease response.
- Author
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Toth, Kathryn A., Buckley, Samantha F., Noren, Hunter, Neely, Karen L., and Walker, Brian K.
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CORAL diseases ,CORALS ,ENDEMIC diseases ,CORAL reefs & islands ,SCLERACTINIA ,CORAL bleaching ,DISEASE prevalence - Abstract
The presence and abundance of reef-building corals are crucial to the long-term existence of Caribbean coral reef ecosystems, providing both direct and indirect, local and global, ecological, economic, and social benefits. In 2014, stony coral tissue loss disease (SCTLD) was first identified in southeast Florida and remains endemic to the region, while continuing to spread throughout the Caribbean. Effective in situ intervention treatments using antibiotic paste can halt lesion progression on Montastraea cavernosa up to 90% of the time. This study investigated intervention activities over a three-year period to identify efficiencies in disease response. Since May 2019, 1,037 corals, >85% of which were M. cavernosa, were treated during disease intervention dives in southeast Florida. Treated coral density, the number of treated corals per meter along a dive track, was significantly higher in the first year compared to subsequent years and displayed annual peaks in late summer each year. Season significantly influenced treatment density, leading to higher values in the wet season across all years, 2019 to 2022. Areas of highest treatment density were identified between Haulover Inlet and Government Cut near Miami and Hillsboro Inlet in northern Broward County. Areas with the highest treatment density were only identified in the first year, suggesting that broadscale interventions may have decreased disease prevalence in subsequent years. Results indicate that in endemic areas with sporadic and dynamic disease prevalence, intervention efforts should be weighted proportionally across space and time to maximize intervention efficiency. This study provides optimistic results for the potential of interventions reducing disease prevalence and supports that disease interventions are an effective coral restoration tool that can decrease the increasing burden on post hoc coral restoration. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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12. Protein arginine methyltransferase 1 is a therapeutic vulnerability in multiple myeloma.
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Nguyen, Hong Phuong, Le, Anh Quynh, Liu, Enze, Cesarano, Annamaria, DiMeo, Francesco, Perna, Fabiana, Kapur, Reuben, Walker, Brian A., and Tran, Ngoc Tung
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PROTEIN arginine methyltransferases ,MULTIPLE myeloma ,BONE marrow cells ,CELL cycle ,PLASMACYTOMA ,CELL death - Abstract
Multiple myeloma (MM) is a devastating plasma cell malignancy characterized by the expansion of aberrant monoclonal plasma cells in the bone marrow, leading to severe clinical manifestations and poor prognosis, particularly in relapsed/ refractory cases. Identifying novel therapeutic targets is crucial to improve treatment outcomes in these patients. In this study, we investigated the role of the protein arginine methyltransferase 1 (PRMT1) in MM pathogenesis and explored its potential as a therapeutic target. We observed that PRMT1, responsible for most asymmetric di-methylation in cells, exhibited the highest expression among PRMT family members in MM cell lines and primary MM cells. Importantly, PRMT1 expression was significantly elevated in relapsed/refractory patients compared to newly diagnosed patients. High expression of PRMT1 expression was strongly associated with poor prognosis. We found that genetic or enzymatic inhibition of PRMT1 impaired MM cell growth, induced cell cycle arrest, and triggered cell death. Treatment with MS023, a potent PRMT type I inhibitor, demonstrated a robust inhibitory effect on the viability of primary cells isolated from newly diagnosed and proteasome inhibitor-relapsed/ refractory patients in a dose-dependent manner. Suppression of PRMT1 downregulated genes related to cell division and upregulated genes associated with apoptosis pathway. We also found that genes related to immune response and lymphocyte activation were significantly upregulated in PRMT1-suppressed cells. Notably, the activation status of T cells was strikingly enhanced upon coculturing with PRMT1-KO MM cells. In vivo studies using a xenograft model revealed that targeting PRMT1 by either CRISPR/Cas9-mediated knockout or MS023 treatment significantly attenuated MM tumor growth and prolonged the survival of tumor-bearing mice. Histological analysis further confirmed increased apoptotic cell death in MS023-treated tumors. Collectively, our findings establish PRMT1 as an indispensable and novel therapeutic vulnerability in MM. The Multiple myeloma (MM) is a devastating plasma cell malignancy characterized by the expansion of aberrant monoclonal plasma cells in the bone marrow, leading to severe clinical manifestations and poor prognosis, particularly in relapsed/ refractory cases. Identifying novel therapeutic targets is crucial to improve treatment outcomes in these patients. In this study, we investigated the role of the protein arginine methyltransferase 1 (PRMT1) in MM pathogenesis and explored its potential as a therapeutic target. We observed that PRMT1, responsible for most asymmetric di-methylation in cells, exhibited the highest expression among PRMT family members in MM cell lines and primary MM cells. Importantly, PRMT1 expression was significantly elevated in relapsed/refractory patients compared to newly diagnosed patients. High expression of PRMT1 expression was strongly associated with poor prognosis. We found that genetic or enzymatic inhibition of PRMT1 impaired MM cell growth, induced cell cycle arrest, and triggered cell death. Treatment with MS023, a potent PRMT type I inhibitor, demonstrated a robust inhibitory effect on the viability of primary cells isolated from newly diagnosed and proteasome inhibitor-relapsed/ refractory patients in a dose-dependent manner. Suppression of PRMT1 downregulated genes related to cell division and upregulated genes associated with apoptosis pathway. We also found that genes related to immune response and lymphocyte activation were significantly upregulated in PRMT1-suppressed cells. Notably, the activation status of T cells was strikingly enhanced upon coculturing with PRMT1-KO MM cells. In vivo studies using a xenograft model revealed that targeting PRMT1 by either CRISPR/Cas9-mediated knockout or MS023 treatment significantly attenuated MM tumor growth and prolonged the survival of tumor-bearing mice. Histological analysis further confirmed increased apoptotic cell death in MS023-treated tumors. Collectively, our findings establish PRMT1 as an indispensable and novel therapeutic vulnerability in MM. The [ABSTRACT FROM AUTHOR]
- Published
- 2023
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13. Dehydrogenative Conversions of Aldehydes and Amines to Amides Catalyzed by a Nickel(II) Pincer Complex.
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Szwedo, Peter, Jumper, Travis, Sanford, Karie, Arnold, Taylor, Coffman, Sarah, Hokes, Davonte, Munshi, Pradip, Walker, Brian, and Ghosh, Anindya
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AMIDES ,ALDEHYDES ,AMINES ,TURNOVER frequency (Catalysis) ,AROMATIC aldehydes ,NICKEL - Abstract
A C-N cross-coupling approach involving oxidative amidations of aromatic aldehydes in the presence of an amide-based nickel(II) pincer catalyst (2) is demonstrated. Upon optimization, quick reaction times (15 min) and an ideal temperature (25 °C) were established and implemented for the conversion of 33 different amide products using only 0.2 mol% of catalyst. Moderate to good turnover numbers (TONs) were obtained for secondary benzamide products, and moderate TONs were obtained for tertiary benzamide products, with the highest turnover number calculated for the 4-chloro-N-(3-phenylpropyl)benzamide product (4i, 309). Gas chromatographic–mass spectrometric (GC–MS) analysis also indicates the formation of alcohols in different reactions, indicating an oxidative amidation process. Kinetic studies were performed by varying the amount of catalyst, aldehyde, LiHMDS base, and amine substrate to determine the order of reaction for each component. Benzaldehyde and benzaldehyde-d
6 were reacted with benzylamine, and the kH /kD ratio was determined to understand the rate-determining step. Isotope labeling further revealed that deuterium was being transferred to both the alcohol side product and the target amide product. With the help of kinetic data and UV–visible spectra, a mechanism for the amidation process via the catalyst (2) is proposed through a Ni(I)–Ni(III) pathway. [ABSTRACT FROM AUTHOR]- Published
- 2023
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14. Plasma cortisol-linked gene networks in hepatic and adipose tissues implicate corticosteroidbinding globulin in modulating tissue glucocorticoid action and cardiovascular risk.
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Bankier, Sean, Lingfei Wang, Crawford, Andrew, Morgan, Ruth A., Ruusalepp, Arno, Andrew, Ruth, Björkegren, Johan L. M., Walker, Brian R., and Michoel, Tom
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ADIPOSE tissues ,LOCUS (Genetics) ,INTERFERON regulatory factors ,CARDIOVASCULAR diseases risk factors ,GENE expression ,GENETIC variation ,GENE regulatory networks - Abstract
Genome-wide association meta-analysis (GWAMA) by the Cortisol Network (CORNET) consortium identified genetic variants spanning the SERPINA6/SERPINA1 locus on chromosome 14 associated with morning plasma cortisol, cardiovascular disease (CVD), and SERPINA6 mRNA expression encoding corticosteroid-binding globulin (CBG) in the liver. These and other findings indicate that higher plasma cortisol levels are causally associated with CVD; however, the mechanisms by which variations in CBG lead to CVD are undetermined. Using genomic and transcriptomic data from The Stockholm Tartu Atherosclerosis Reverse Networks Engineering Task (STARNET) study, we identified plasma cortisol-linked single-nucleotide polymorphisms (SNPs) that are trans-associated with genes from seven different vascular and metabolic tissues, finding the highest representation of trans-genes in the liver, subcutaneous fat, and visceral abdominal fat, [false discovery rate (FDR) = 15%]. We identified a subset of cortisol-associated trans-genes that are putatively regulated by the glucocorticoid receptor (GR), the primary transcription factor activated by cortisol. Using causal inference, we identified GR-regulated trans-genes that are responsible for the regulation of tissuespecific gene networks. Cis-expression Quantitative Trait Loci (eQTLs) were used as genetic instruments for identification of pairwise causal relationships from which gene networks could be reconstructed. Gene networks were identified in the liver, subcutaneous fat, and visceral abdominal fat, including a high confidence gene network specific to subcutaneous adipose (FDR = 10%) under the regulation of the interferon regulatory transcription factor, IRF2. These data identify a plausible pathway through which variation in the liver CBG production perturbs cortisol-regulated gene networks in peripheral tissues and thereby promote CVD. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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15. Identifying novel mechanisms of biallelic TP53 loss refines poor outcome for patients with multiple myeloma.
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Liu, Enze, Sudha, Parvathi, Becker, Nathan, Jaouadi, Oumaima, Suvannasankha, Attaya, Lee, Kelvin, Abonour, Rafat, Abu Zaid, Mohammad, and Walker, Brian A.
- Subjects
MULTIPLE myeloma ,RANDOM forest algorithms ,OVERALL survival ,REGRESSION analysis ,GENETIC overexpression - Abstract
Biallelic TP53 inactivation is the most important high-risk factor associated with poor survival in multiple myeloma. Classical biallelic TP53 inactivation has been defined as simultaneous mutation and copy number loss in most studies; however, numerous studies have demonstrated that other factors could lead to the inactivation of TP53. Here, we hypothesized that novel biallelic TP53 inactivated samples existed in the multiple myeloma population. A random forest regression model that exploited an expression signature of 16 differentially expressed genes between classical biallelic TP53 and TP53 wild-type samples was subsequently established and used to identify novel biallelic TP53 samples from monoallelic TP53 groups. The model reflected high accuracy and robust performance in newly diagnosed relapsed and refractory populations. Patient survival of classical and novel biallelic TP53 samples was consistently much worse than those with mono-allelic or wild-type TP53 status. We also demonstrated that some predicted biallelic TP53 samples simultaneously had copy number loss and aberrant splicing, resulting in overexpression of high-risk transcript variants, leading to biallelic inactivation. We discovered that splice site mutation and overexpression of the splicing factor MED18 were reasons for aberrant splicing. Taken together, our study unveiled the complex transcriptome of TP53, some of which might benefit future studies targeting abnormal TP53. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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16. Memory deficits in a juvenile rat model of type 1 diabetes are due to excess 11β-HSD1 activity, which is upregulated by high glucose concentrations rather than insulin deficiency.
- Author
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Brossaud, Julie, Bosch-Bouju, Clémentine, Marissal-Arvy, Nathalie, Campas-Lebecque, Marie-Neige, Helbling, Jean-Christophe, Webster, Scott P., Walker, Brian R., Fioramonti, Xavier, Ferreira, Guillaume, Barat, Pascal, Corcuff, Jean-Benoît, and Moisan, Marie-Pierre
- Abstract
Aims/hypothesis: Children with diabetes may display cognitive alterations although vascular disorders have not yet appeared. Variations in glucose levels together with relative insulin deficiency in treated type 1 diabetes have been reported to impact brain function indirectly through dysregulation of the hypothalamus–pituitary–adrenal axis. We have recently shown that enhancement of glucocorticoid levels in children with type 1 diabetes is dependent not only on glucocorticoid secretion but also on glucocorticoid tissue concentrations, which is linked to 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activity. Hypothalamus–pituitary–adrenal axis dysfunction and memory alteration were further dissected in a juvenile rat model of diabetes showing that excess 11β-HSD1 activity within the hippocampus is associated with hippocampal-dependent memory deficits. Here, to investigate the causal relationships between diabetes, 11β-HSD1 activity and hippocampus-dependent memory deficits, we evaluated the beneficial effect of 11β-HSD1 inhibition on hippocampal-related memory in juvenile diabetic rats. We also examined whether diabetes-associated enhancement of hippocampal 11β-HSD1 activity is due to an increase in brain glucose concentrations and/or a decrease in insulin signalling. Methods: Diabetes was induced in juvenile rats by daily i.p. injection of streptozotocin for 2 consecutive days. Inhibition of 11β-HSD1 was obtained by administrating the compound UE2316 twice daily by gavage for 3 weeks, after which hippocampal-dependent object location memory was assessed. Hippocampal 11β-HSD1 activity was estimated by the ratio of corticosterone/dehydrocorticosterone measured by LC/MS. Regulation of 11β-HSD1 activity in response to changes in glucose or insulin levels was determined ex vivo on acute brain hippocampal slices. The insulin regulation of 11β-HSD1 was further examined in vivo using virally mediated knockdown of insulin receptor expression specifically in the hippocampus. Results: Our data show that inhibiting 11β-HSD1 activity prevents hippocampal-related memory deficits in diabetic juvenile rats. A significant increase (53.0±9.9%) in hippocampal 11β-HSD1 activity was found in hippocampal slices incubated in high glucose conditions (13.9 mmol/l) vs normal glucose conditions (2.8 mmol/l) without insulin. However, 11β-HSD1 activity was not affected by variations in insulin concentration either in the hippocampal slices or after a decrease in hippocampal insulin receptor expression. Conclusions/interpretation: Together, these data demonstrate that an increase in 11β-HSD1 activity contributes to memory deficits observed in juvenile diabetic rats and that an excess of hippocampal 11β-HSD1 activity stems from high glucose levels rather than insulin deficiency. 11β-HSD1 might be a therapeutic target for treating cognitive impairments associated with diabetes. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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17. Protein arginine methyltransferase 1 is a therapeutic vulnerability in multiple myeloma.
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Hong Phuong Nguyen, Anh Quynh Le, Enze Liu, Cesarano, Annamaria, DiMeo, Francesco, Perna, Fabiana, Kapur, Reuben, Walker, Brian A., and Ngoc Tung Tran
- Subjects
PROTEIN arginine methyltransferases ,MULTIPLE myeloma ,PLASMACYTOMA ,BONE marrow cells ,CELL cycle ,LYMPHOCYTE transformation - Abstract
Multiple myeloma (MM) is a devastating plasma cell malignancy characterized by the expansion of aberrant monoclonal plasma cells in the bone marrow, leading to severe clinical manifestations and poor prognosis, particularly in relapsed/ refractory cases. Identifying novel therapeutic targets is crucial to improve treatment outcomes in these patients. In this study, we investigated the role of the protein arginine methyltransferase 1 (PRMT1) in MM pathogenesis and explored its potential as a therapeutic target. We observed that PRMT1, responsible for most asymmetric di-methylation in cells, exhibited the highest expression among PRMT family members in MM cell lines and primary MM cells. Importantly, PRMT1 expression was significantly elevated in relapsed/refractory patients compared to newly diagnosed patients. High expression of PRMT1 expression was strongly associated with poor prognosis. We found that genetic or enzymatic inhibition of PRMT1 impaired MM cell growth, induced cell cycle arrest, and triggered cell death. Treatment with MS023, a potent PRMT type I inhibitor, demonstrated a robust inhibitory effect on the viability of primary cells isolated from newly diagnosed and proteasome inhibitor-relapsed/ refractory patients in a dose-dependent manner. Suppression of PRMT1 downregulated genes related to cell division and upregulated genes associated with apoptosis pathway. We also found that genes related to immune response and lymphocyte activation were significantly upregulated in PRMT1-suppressed cells. Notably, the activation status of T cells was strikingly enhanced upon coculturing with PRMT1-KO MM cells. In vivo studies using a xenograft model revealed that targeting PRMT1 by either CRISPR/Cas9-mediated knockout or MS023 treatment significantly attenuated MM tumor growth and prolonged the survival of tumor-bearing mice. Histological analysis further confirmed increased apoptotic cell death in MS023-treated tumors. Collectively, our findings establish PRMT1 as an indispensable and novel therapeutic vulnerability in MM. The elevated expression of PRMT1 in relapsed/refractory patients underscores its potential as a target for overcoming treatment resistance. Moreover, our results highlight the efficacy of MS023 as a promising therapeutic agent against MM, offering new avenues for therapeutic approaches in relapsed/refractory MM. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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18. Response diversity as a sustainability strategy.
- Author
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Walker, Brian, Crépin, Anne-Sophie, Nyström, Magnus, Anderies, John M., Andersson, Erik, Elmqvist, Thomas, Queiroz, Cibele, Barrett, Scott, Bennett, Elena, Cardenas, Juan Camilo, Carpenter, Stephen R., Chapin III, F. Stuart, de Zeeuw, Aart, Fischer, Joern, Folke, Carl, Levin, Simon, Nyborg, Karine, Polasky, Stephen, Segerson, Kathleen, and Seto, Karen C.
- Published
- 2023
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19. 11β-HSD1 inhibition does not affect murine tumour angiogenesis but may exert a selective effect on tumour growth by modulating inflammation and fibrosis.
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Davidson, Callam T., Miller, Eileen, Muir, Morwenna, Dawson, John C., Lee, Martin, Aitken, Stuart, Serrels, Alan, Webster, Scott P., Homer, Natalie Z. M., Andrew, Ruth, Brunton, Valerie G., Hadoke, Patrick W. F., and Walker, Brian R.
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SECOND harmonic generation ,NEOVASCULARIZATION ,GLUCOCORTICOID receptors ,PANCREATIC duct ,CELL imaging - Abstract
Glucocorticoids inhibit angiogenesis by activating the glucocorticoid receptor. Inhibition of the glucocorticoid-activating enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) reduces tissue-specific glucocorticoid action and promotes angiogenesis in murine models of myocardial infarction. Angiogenesis is important in the growth of some solid tumours. This study used murine models of squamous cell carcinoma (SCC) and pancreatic ductal adenocarcinoma (PDAC) to test the hypothesis that 11β-HSD1 inhibition promotes angiogenesis and subsequent tumour growth. SCC or PDAC cells were injected into female FVB/N or C57BL6/J mice fed either standard diet, or diet containing the 11β-HSD1 inhibitor UE2316. SCC tumours grew more rapidly in UE2316-treated mice, reaching a larger (P<0.01) final volume (0.158 ± 0.037 cm
3 ) than in control mice (0.051 ± 0.007 cm3 ). However, PDAC tumour growth was unaffected. Immunofluorescent analysis of SCC tumours did not show differences in vessel density (CD31/alpha-smooth muscle actin) or cell proliferation (Ki67) after 11β-HSD1 inhibition, and immunohistochemistry of SCC tumours did not show changes in inflammatory cell (CD3- or F4/80-positive) infiltration. In culture, the growth/viability (assessed by live cell imaging) of SCC cells was not affected by UE2316 or corticosterone. Second Harmonic Generation microscopy showed that UE2316 reduced Type I collagen (P<0.001), whilst RNA-sequencing revealed that multiple factors involved in the innate immune/inflammatory response were reduced in UE2316-treated SCC tumours. 11β-HSD1 inhibition increases SCC tumour growth, likely via suppression of inflammatory/immune cell signalling and extracellular matrix deposition, but does not promote tumour angiogenesis or growth of all solid tumours. [ABSTRACT FROM AUTHOR]- Published
- 2023
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20. What is the 12-Term VNA Calibration Model? Learn about the 12-term error model used to characterize systematic errors encountered during VNA measurements.
- Author
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Walker, Brian
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MEASUREMENT errors ,CALIBRATION ,REFLECTANCE ,MEASUREMENT ,FLOWGRAPHS ,MATRIX multiplications - Abstract
This article discusses the 12-term error model used to characterize systematic errors encountered during vector network analyzer (VNA) measurements. VNAs must be calibrated due to loss and delay in test cables, which can affect phase measurements. The 12-term error model involves creating error boxes on either side of the device under test (DUT) and attaching a perfect VNA to each side. The article explains the various error terms and how they can be determined through measurements of known calibration standards. The 12 error terms can then be used to convert measured S-parameters into actual S-parameters of the DUT. [Extracted from the article]
- Published
- 2024
21. A Sweet Voice: Acute Febrile Neutrophilic Dermatosis of the Larynx.
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Walker, Brian A., Stull, Lindsey B., and Hines, J. Peyton
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STEROID drugs ,CONSERVATIVE treatment ,FEVER ,ERYTHEMA ,EXANTHEMA ,TREATMENT effectiveness ,LARYNGEAL diseases ,SWEET'S syndrome ,RARE diseases ,OTOLARYNGOLOGY ,SYMPTOMS - Abstract
Significance Statement: Acute febrile neutrophilic dermatosis (Sweet syndrome) is a rare idiopathic condition characterized by fever and whole-body rash of tender erythematous plaques of unknown etiology. Otorhinolaryngologic manifestations of the disease can be severe, yet they are sparsely reported in the literature. We present the first documented case of laryngeal involvement of Sweet syndrome. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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22. Alternative splicing in multiple myeloma is associated with the non-homologous end joining pathway.
- Author
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Liu, Enze, Becker, Nathan, Sudha, Parvathi, Dong, Chuanpeng, Liu, Yunlong, Keats, Jonathan, Morgan, Gareth, and Walker, Brian A.
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ALTERNATIVE RNA splicing ,MULTIPLE myeloma ,DNA repair - Abstract
Alternative splicing plays a pivotal role in tumorigenesis and proliferation. However, its pattern and pathogenic role has not been systematically analyzed in multiple myeloma or its subtypes. Alternative splicing profiles for 598 newly diagnosed myeloma patients with comprehensive genomic annotation identified primary translocations, 1q amplification, and DIS3 events to have more differentially spliced events than those without. Splicing levels were correlated with expression of splicing factors. Moreover, the non-homologous end joining pathway was an independent factor that was highly associated with splicing frequency as well as an increased number of structural variants. We therefore identify an axis of high-risk disease encompassing expression of the non-homologous end joining pathway, increase structural variants, and increased alternative splicing that are linked together. This indicates a joint pathogenic role for DNA damage response and alternative RNA processing in myeloma. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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23. Non-invasive in vivo assessment of 11β-hydroxysteroid dehydrogenase type 1 activity by 19F-Magnetic Resonance Spectroscopy.
- Author
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Naredo-Gonzalez, Gregorio, Upreti, Rita, Jansen, Maurits A., Semple, Scott, Sutcliffe, Oliver B., Marshall, Ian, Walker, Brian R., and Andrew, Ruth
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NUCLEAR magnetic resonance spectroscopy ,ORAL drug administration ,LABORATORY rats ,RESONANCE ,SPECTROMETRY - Abstract
11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) amplifies tissue glucocorticoid levels and is a pharmaceutical target in diabetes and cognitive decline. Clinical translation of inhibitors is hampered by lack of in vivo pharmacodynamic biomarkers. Our goal was to monitor substrates and products of 11β-HSD1 non-invasively in liver via
19 Fluorine magnetic resonance spectroscopy (19 F-MRS). Interconversion of mono/poly-fluorinated substrate/product pairs was studied in Wistar rats (male, n = 6) and healthy men (n = 3) using 7T and 3T MRI scanners, respectively. Here we show that the in vitro limit of detection, as absolute fluorine content, was 0.625 μmole in blood. Mono-fluorinated steroids, dexamethasone and 11-dehydrodexamethasone, were detected in phantoms but not in vivo in human liver following oral dosing. A non-steroidal polyfluorinated tracer, 2-(phenylsulfonyl)-1-(4-(trifluoromethyl)phenyl)ethanone and its metabolic product were detected in vivo in rat liver after oral administration of the keto-substrate, reading out reductase activity. Administration of a selective 11β-HSD1 inhibitor in vivo in rats altered total liver19 F-MRS signal. We conclude that there is insufficient sensitivity to measure mono-fluorinated tracers in vivo in man with current dosage regimens and clinical scanners. However, since reductase activity was observed in rats using poly-fluorinated tracers, this concept could be pursued for translation to man with further development. [ABSTRACT FROM AUTHOR]- Published
- 2022
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24. Earth stewardship: Shaping a sustainable future through interacting policy and norm shifts.
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Chapin III, F. Stuart, Weber, Elke U., Bennett, Elena M., Biggs, Reinette, van den Bergh, Jeroen, Adger, W. Neil, Crépin, Anne-Sophie, Polasky, Stephen, Folke, Carl, Scheffer, Marten, Segerson, Kathleen, Anderies, John M., Barrett, Scott, Cardenas, Juan-Camilo, Carpenter, Stephen R., Fischer, Joern, Kautsky, Nils, Levin, Simon A., Shogren, Jason F., and Walker, Brian
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SUSTAINABILITY ,SHAPE of the earth ,EARTH currents ,INCENTIVE (Psychology) ,SOCIAL norms - Abstract
Transformation toward a sustainable future requires an earth stewardship approach to shift society from its current goal of increasing material wealth to a vision of sustaining built, natural, human, and social capital—equitably distributed across society, within and among nations. Widespread concern about earth's current trajectory and support for actions that would foster more sustainable pathways suggests potential social tipping points in public demand for an earth stewardship vision. Here, we draw on empirical studies and theory to show that movement toward a stewardship vision can be facilitated by changes in either policy incentives or social norms. Our novel contribution is to point out that both norms and incentives must change and can do so interactively. This can be facilitated through leverage points and complementarities across policy areas, based on values, system design, and agency. Potential catalysts include novel democratic institutions and engagement of non-governmental actors, such as businesses, civic leaders, and social movements as agents for redistribution of power. Because no single intervention will transform the world, a key challenge is to align actions to be synergistic, persistent, and scalable. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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25. The spatio-temporal evolution of multiple myeloma from baseline to relapse-refractory states.
- Author
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Rasche, Leo, Schinke, Carolina, Maura, Francesco, Bauer, Michael A., Ashby, Cody, Deshpande, Shayu, Poos, Alexandra M., Zangari, Maurizio, Thanendrarajan, Sharmilan, Davies, Faith E., Walker, Brian A., Barlogie, Bart, Landgren, Ola, Morgan, Gareth J., van Rhee, Frits, and Weinhold, Niels
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SPATIOTEMPORAL processes ,MULTIPLE myeloma ,BONE marrow ,DISEASE relapse - Abstract
Deciphering Multiple Myeloma evolution in the whole bone marrow is key to inform curative strategies. Here, we perform spatial-longitudinal whole-exome sequencing, including 140 samples collected from 24 Multiple Myeloma patients during up to 14 years. Applying imaging-guided sampling we observe three evolutionary patterns, including relapse driven by a single-cell expansion, competing/co-existing sub-clones, and unique sub-clones at distinct locations. While we do not find the unique relapse sub-clone in the baseline focal lesion(s), we show a close phylogenetic relationship between baseline focal lesions and relapse disease, highlighting focal lesions as hotspots of tumor evolution. In patients with ≥3 focal lesions on positron-emission-tomography at diagnosis, relapse is driven by multiple distinct sub-clones, whereas in other patients, a single-cell expansion is typically seen (p < 0.01). Notably, we observe resistant sub-clones that can be hidden over years, suggesting that a prerequisite for curative therapies would be to overcome not only tumor heterogeneity but also dormancy. Spatially and temporally resolved data can improve our understanding of evolution and treatment resistance in multiple myeloma (MM). Here, the authors analyse spatial and longitudinal heterogeneity in MM patients using multi-region sequencing, and identify subclones associated with relapse and therapy resistance. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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- View/download PDF
26. Corticotroph isolation from Pomc‐eGFP mice reveals sustained transcriptional dysregulation characterising a mouse model of glucocorticoid‐induced suppression of the hypothalamus–pituitary–adrenal axis.
- Author
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Duncan, Peter J., McClafferty, Heather, Nolan, Oscar, Ding, Qinghui, Homer, Natalie Z. M., Le Tissier, Paul, Walker, Brian R., Shipston, Michael J., Romanò, Nicola, and Chambers, Thomas J. G.
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HYPOTHALAMIC-pituitary-adrenal axis ,LABORATORY mice ,ANIMAL disease models ,TRANSGENIC mice ,DRINKING water - Abstract
Glucocorticoids (GC) are prescribed for periods > 3 months to 1%–3% of the UK population; 10%–50% of these patients develop hypothalamus‐pituitary–adrenal (HPA) axis suppression, which may last over 6 months and is associated with morbidity and mortality. Recovery of the pituitary and hypothalamus is necessary for recovery of adrenal function. We developed a mouse model of dexamethasone (DEX)‐induced HPA axis dysfunction aiming to further explore recovery in the pituitary. Adult male wild‐type C57BL6/J or Pomc‐eGFP transgenic mice were randomly assigned to receive DEX (approximately 0.4 mg kg–1 bodyweight day–1) or vehicle via drinking water for 4 weeks following which treatment was withdrawn and tissues were harvested after another 0, 1, and 4 weeks. Corticotrophs were isolated from Pomc‐eGFP pituitaries using fluorescence‐activated cell sorting, and RNA extracted for RNA‐sequencing. DEX treatment suppressed corticosterone production, which remained partially suppressed at least 1 week following DEX withdrawal. In the adrenal, Hsd3b2, Cyp11a1, and Mc2r mRNA levels were significantly reduced at time 0, with Mc2r and Cyp11a1 remaining reduced 1 week following DEX withdrawal. The corticotroph transcriptome was modified by DEX treatment, with some differences between groups persisting 4 weeks following withdrawal. No genes supressed by DEX exhibited ongoing attenuation 1 and 4 weeks following withdrawal, whereas only two genes were upregulated and remained so following withdrawal. A pattern of rebound at 1 and 4 weeks was observed in 14 genes that increased following suppression, and in six genes that were reduced by DEX and then increased. Chronic GC treatment may induce persistent changes in the pituitary that may influence future response to GC treatment or stress. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
27. Genetic subtypes of smoldering multiple myeloma are associated with distinct pathogenic phenotypes and clinical outcomes.
- Author
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Bustoros, Mark, Anand, Shankara, Sklavenitis-Pistofidis, Romanos, Redd, Robert, Boyle, Eileen M., Zhitomirsky, Benny, Dunford, Andrew J., Tai, Yu-Tzu, Chavda, Selina J., Boehner, Cody, Neuse, Carl Jannes, Rahmat, Mahshid, Dutta, Ankit, Casneuf, Tineke, Verona, Raluca, Kastritis, Efstathis, Trippa, Lorenzo, Stewart, Chip, Walker, Brian A., and Davies, Faith E.
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MULTIPLE myeloma ,MATRIX decomposition ,TREATMENT effectiveness ,DISEASE progression - Abstract
Smoldering multiple myeloma (SMM) is a precursor condition of multiple myeloma (MM) with significant heterogeneity in disease progression. Existing clinical models of progression risk do not fully capture this heterogeneity. Here we integrate 42 genetic alterations from 214 SMM patients using unsupervised binary matrix factorization (BMF) clustering and identify six distinct genetic subtypes. These subtypes are differentially associated with established MM-related RNA signatures, oncogenic and immune transcriptional profiles, and evolving clinical biomarkers. Three genetic subtypes are associated with increased risk of progression to active MM in both the primary and validation cohorts, indicating they can be used to better predict high and low-risk patients within the currently used clinical risk stratification models. Existing clinical models cannot fully capture smoldering multiple myeloma (SMM) heterogeneity. Here, integration of 42 genetic alterations from 214 SMM patients using an unsupervised binary matrix factorization clustering approach results in the identification of 6 distinct molecular and clinical subtypes. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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- View/download PDF
28. Heritability of Urinary Amines, Organic Acids, and Steroid Hormones in Children.
- Author
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Hagenbeek, Fiona A., van Dongen, Jenny, Pool, René, Harms, Amy C., Roetman, Peter J., Fanos, Vassilios, van Keulen, Britt J., Walker, Brian R., Karu, Naama, Hulshoff Pol, Hilleke E., Rotteveel, Joost, Finken, Martijn J. J., Vermeiren, Robert R. J. M., Kluft, Cornelis, Bartels, Meike, Hankemeier, Thomas, and Boomsma, Dorret I.
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STEROID hormones ,HERITABILITY ,ORGANIC acids ,AMINES ,INDIVIDUAL differences ,METABOLITES ,METABOLOMICS ,HETEROSIS in plants - Abstract
Variation in metabolite levels reflects individual differences in genetic and environmental factors. Here, we investigated the role of these factors in urinary metabolomics data in children. We examined the effects of sex and age on 86 metabolites, as measured on three metabolomics platforms that target amines, organic acids, and steroid hormones. Next, we estimated their heritability in a twin cohort of 1300 twins (age range: 5.7–12.9 years). We observed associations between age and 50 metabolites and between sex and 21 metabolites. The monozygotic (MZ) and dizygotic (DZ) correlations for the urinary metabolites indicated a role for non-additive genetic factors for 50 amines, 13 organic acids, and 6 steroids. The average broad-sense heritability for these amines, organic acids, and steroids was 0.49 (range: 0.25–0.64), 0.50 (range: 0.33–0.62), and 0.64 (range: 0.43–0.81), respectively. For 6 amines, 7 organic acids, and 4 steroids the twin correlations indicated a role for shared environmental factors and the average narrow-sense heritability was 0.50 (range: 0.37–0.68), 0.50 (range; 0.23–0.61), and 0.47 (range: 0.32–0.70) for these amines, organic acids, and steroids. We conclude that urinary metabolites in children have substantial heritability, with similar estimates for amines and organic acids, and higher estimates for steroid hormones. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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29. Incidence of Concomitant Semicircular Canal Dehiscence With Otosclerosis.
- Author
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Walker, Brian A., Thorwarth, Ryan M., Stull, Lindsey L., Hoxworth, Joseph M., Deep, Nicholas L., and Weisskopf, Peter A.
- Published
- 2022
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30. Structural variants shape the genomic landscape and clinical outcome of multiple myeloma.
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Ashby, Cody, Boyle, Eileen M., Bauer, Michael A., Mikulasova, Aneta, Wardell, Christopher P., Williams, Louis, Siegel, Ariel, Blaney, Patrick, Braunstein, Marc, Kaminetsky, David, Keats, Jonathan, Maura, Francesco, Landgren, Ola, Walker, Brian A., Davies, Faith E., and Morgan, Gareth J.
- Subjects
MULTIPLE myeloma ,TREATMENT effectiveness ,CHROMOSOMAL rearrangement ,RNA sequencing ,PLASMACYTOMA - Abstract
Deciphering genomic architecture is key to identifying novel disease drivers and understanding the mechanisms underlying myeloma initiation and progression. In this work, using the CoMMpass dataset, we show that structural variants (SV) occur in a nonrandom fashion throughout the genome with an increased frequency in the t(4;14), RB1, or TP53 mutated cases and reduced frequency in t(11;14) cases. By mapping sites of chromosomal rearrangements to topologically associated domains and identifying significantly upregulated genes by RNAseq we identify both predicted and novel putative driver genes. These data highlight the heterogeneity of transcriptional dysregulation occurring as a consequence of both the canonical and novel structural variants. Further, it shows that the complex rearrangements chromoplexy, chromothripsis and templated insertions are common in MM with each variant having its own distinct frequency and impact on clinical outcome. Chromothripsis is associated with a significant independent negative impact on clinical outcome in newly diagnosed cases consistent with its use alongside other clinical and genetic risk factors to identify prognosis. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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31. Governance in the Face of Extreme Events: Lessons from Evolutionary Processes for Structuring Interventions, and the Need to Go Beyond.
- Author
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Levin, Simon A., Anderies, John M., Adger, Neil, Barrett, Scott, Bennett, Elena M., Cardenas, Juan Camilo, Carpenter, Stephen R., Crépin, Anne-Sophie, Ehrlich, Paul, Fischer, Joern, Folke, Carl, Kautsky, Nils, Kling, Catherine, Nyborg, Karine, Polasky, Stephen, Scheffer, Marten, Segerson, Kathleen, Shogren, Jason, van den Bergh, Jeroen, and Walker, Brian
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ECOLOGICAL disturbances ,COMPLEXITY (Philosophy) ,BIOLOGICAL systems ,COLLECTIVE action - Abstract
The increasing frequency of extreme events, exogenous and endogenous, poses challenges for our societies. The current pandemic is a case in point; but "once-in-a-century" weather events are also becoming more common, leading to erosion, wildfire and even volcanic events that change ecosystems and disturbance regimes, threaten the sustainability of our life-support systems, and challenge the robustness and resilience of societies. Dealing with extremes will require new approaches and large-scale collective action. Preemptive measures can increase general resilience, a first line of protection, while more specific reactive responses are developed. Preemptive measures also can minimize the negative effects of events that cannot be avoided. In this paper, we first explore approaches to prevention, mitigation and adaptation, drawing inspiration from how evolutionary challenges have made biological systems robust and resilient, and from the general theory of complex adaptive systems. We argue further that proactive steps that go beyond will be necessary to reduce unacceptable consequences. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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32. Impact of Etiological Cytogenetic Abnormalities on the Depth of Immunoparesis and Survival in Newly Diagnosed Multiple Myeloma.
- Author
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Caro, Jessica, Cairns, David, Menzies, Tom, Boyle, Eileen, Pawlyn, Charlotte, Cook, Gordon, Kaiser, Martin, Walker, Brian A, Owen, Roger, Jackson, Graham H, Morgan, Gareth J, Heaney, Jennifer, Drayson, Mark T, and Davies, Faith E
- Published
- 2022
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33. Diagnostic Evidence GAuge of Single cells (DEGAS): a flexible deep transfer learning framework for prioritizing cells in relation to disease.
- Author
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Johnson, Travis S., Yu, Christina Y., Huang, Zhi, Xu, Siwen, Wang, Tongxin, Dong, Chuanpeng, Shao, Wei, Zaid, Mohammad Abu, Huang, Xiaoqing, Wang, Yijie, Bartlett, Christopher, Zhang, Yan, Walker, Brian A., Liu, Yunlong, Huang, Kun, and Zhang, Jie
- Subjects
DEEP learning ,MULTIPLE myeloma ,ALZHEIMER'S disease ,GLIOBLASTOMA multiforme ,OPEN learning - Abstract
We propose DEGAS (Diagnostic Evidence GAuge of Single cells), a novel deep transfer learning framework, to transfer disease information from patients to cells. We call such transferrable information "impressions," which allow individual cells to be associated with disease attributes like diagnosis, prognosis, and response to therapy. Using simulated data and ten diverse single-cell and patient bulk tissue transcriptomic datasets from glioblastoma multiforme (GBM), Alzheimer's disease (AD), and multiple myeloma (MM), we demonstrate the feasibility, flexibility, and broad applications of the DEGAS framework. DEGAS analysis on myeloma single-cell transcriptomics identified PHF19
high myeloma cells associated with progression. Availability: https://github.com/tsteelejohnson91/DEGAS. [ABSTRACT FROM AUTHOR]- Published
- 2022
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- View/download PDF
34. Physiological parameters of a plover during nonbreeding and breeding seasons in Patagonia, Argentina.
- Author
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D'Amico, Verónica L., Hevia, Glenda D., Walker, Brian, González, Patricia M., and Bertellotti, Marcelo
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PLOVERS ,ENDANGERED species ,ENVIRONMENTAL protection ,CLIMATE change - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2022
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35. Paradoxical sex-specific patterns of autoantibody response to SARS-CoV-2 infection.
- Author
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Liu, Yunxian, Ebinger, Joseph E., Mostafa, Rowann, Budde, Petra, Gajewski, Jana, Walker, Brian, Joung, Sandy, Wu, Min, Bräutigam, Manuel, Hesping, Franziska, Rupieper, Elena, Schubert, Ann-Sophie, Zucht, Hans-Dieter, Braun, Jonathan, Melmed, Gil Y., Sobhani, Kimia, Arditi, Moshe, Van Eyk, Jennifer E., Cheng, Susan, and Fert-Bober, Justyna
- Subjects
AUTOANTIBODIES ,SARS-CoV-2 ,COVID-19 ,INFECTION ,AUTOIMMUNE diseases ,AUTOANTIGENS - Abstract
Background: Pronounced sex differences in the susceptibility and response to SARS-CoV-2 infection remain poorly understood. Emerging evidence has highlighted the potential importance of autoimmune activation in modulating the acute response and recovery trajectories following SARS-CoV-2 exposure. Given that immune-inflammatory activity can be sex-biased in the setting of severe COVID-19 illness, the aim of the study was to examine sex-specific autoimmune reactivity to SARS-CoV-2 in the absence of extreme clinical disease.Methods: In this study, we assessed autoantibody (AAB) reactivity to 91 autoantigens previously linked to a range of classic autoimmune diseases in a cohort of 177 participants (65% women, 35% men, mean age of 35) with confirmed evidence of prior SARS-CoV-2 infection based on presence of antibody to the nucleocapsid protein of SARS-CoV-2. Data were compared to 53 pre-pandemic healthy controls (49% women, 51% men). For each participant, socio-demographic data, serological analyses, SARS-CoV-2 infection status and COVID-19 related symptoms were collected by an electronic survey of questions. The symptoms burden score was constructed based on the total number of reported symptoms (N = 21) experienced within 6 months prior to the blood draw, wherein a greater number of symptoms corresponded to a higher score and assigned as more severe burden.Results: In multivariable analyses, we observed sex-specific patterns of autoreactivity associated with the presence or absence (as well as timing and clustering of symptoms) associated with prior COVID-19 illness. Whereas the overall AAB response was more prominent in women following asymptomatic infection, the breadth and extent of AAB reactivity was more prominent in men following at least mildly symptomatic infection. Notably, the observed reactivity included distinct antigens with molecular homology with SARS-CoV-2.Conclusion: Our results reveal that prior SARS-CoV-2 infection, even in the absence of severe clinical disease, can lead to a broad AAB response that exhibits sex-specific patterns of prevalence and antigen selectivity. Further understanding of the nature of triggered AAB activation among men and women exposed to SARS-CoV-2 will be essential for developing effective interventions against immune-mediated sequelae of COVID-19. [ABSTRACT FROM AUTHOR]- Published
- 2021
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- View/download PDF
36. Insights into high-risk multiple myeloma from an analysis of the role of PHF19 in cancer.
- Author
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Ghamlouch, Hussein, Boyle, Eileen M., Blaney, Patrick, Wang, Yubao, Choi, Jinyoung, Williams, Louis, Bauer, Michael, Auclair, Daniel, Bruno, Benedetto, Walker, Brian A., Davies, Faith E., and Morgan, Gareth J.
- Subjects
MULTIPLE myeloma ,SOMATIC mutation ,CELL growth ,HEMATOLOGIC malignancies ,GENETIC regulation ,DIAGNOSIS - Abstract
Despite improvements in outcome, 15-25% of newly diagnosed multiple myeloma (MM) patients have treatment resistant high-risk (HR) disease with a poor survival. The lack of a genetic basis for HR has focused attention on the role played by epigenetic changes. Aberrant expression and somatic mutations affecting genes involved in the regulation of tri-methylation of the lysine (K) 27 on histone 3 H3 (H3K27me3) are common in cancer. H3K27me3 is catalyzed by EZH2, the catalytic subunit of the Polycomb Repressive Complex 2 (PRC2). The deregulation of H3K27me3 has been shown to be involved in oncogenic transformation and tumor progression in a variety of hematological malignancies including MM. Recently we have shown that aberrant overexpression of the PRC2 subunit PHD Finger Protein 19 (PHF19) is the most significant overall contributor to HR status further focusing attention on the role played by epigenetic change in MM. By modulating both the PRC2/EZH2 catalytic activity and recruitment, PHF19 regulates the expression of key genes involved in cell growth and differentiation. Here we review the expression, regulation and function of PHF19 both in normal and the pathological contexts of solid cancers and MM. We present evidence that strongly implicates PHF19 in the regulation of genes important in cell cycle and the genetic stability of MM cells making it highly relevant to HR MM behavior. A detailed understanding of the normal and pathological functions of PHF19 will allow us to design therapeutic strategies able to target aggressive subsets of MM. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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- View/download PDF
37. Chromosomal 1q21 abnormalities in multiple myeloma: a review of translational, clinical research, and therapeutic strategies.
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Bisht, Kamlesh, Walker, Brian, Kumar, Shaji K., Spicka, Ivan, Moreau, Philippe, Martin, Tom, Costa, Luciano J., Richter, Joshua, Fukao, Taro, Macé, Sandrine, and van de Velde, Helgi
- Published
- 2021
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38. High‐risk transcriptional profiles in multiple myeloma are an acquired feature that can occur in any subtype and more frequently with each subsequent relapse.
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Boyle, Eileen M., Rosenthal, Adam, Wang, Yan, Farmer, Philip, Rutherford, Michael, Ashby, Cody, Bauer, Michael, Johnson, Sarah K., Wardell, Christopher P., Hoering, Antje, Schinke, Carolina, Thanendrarajan, Sharmilan, Zangari, Maurizio, Barlogie, Bart, Davies, Faith E., Walker, Brian A., van Rhee, Frits, and Morgan, Gareth J.
- Subjects
BLADDER cancer ,MULTIPLE myeloma ,GENE expression profiling ,PROGNOSIS - Abstract
Among these patients, 784 patients had at least two GEP performed during their disease course including 147 patients with a paired diagnosis and relapse sample. Keywords: gene expression; myeloma; risk factors EN gene expression myeloma risk factors 283 286 4 10/12/21 20211015 NES 211015 Clustering of gene expression profiling (GEP) signatures at diagnosis identified a number of distinct biological subgroups that correlate with clinical outcome in multiple myeloma (MM).1-4 Some of these clusters are defined by an aetiologic genetic event whereas others, such as the proliferation cluster (PR) and GEP70 risk, relate to acquired transcriptional patterns associated with adverse clinical behaviour irrespective of the underlying disease subgroup.1,2 Much has been written about the GEP70 risk classification but less has been presented about the PR cluster which is of particular importance as it was identified by the very first unsupervised clustering analysis2 and confirmed in other datasets.5 Key features of this group include the expression of typical proliferation genes and an adverse clinical outcome.6 The evolutionary behaviour of MM is now more clearly understood as is the natural history of MM which is associated with increasingly short periods of remission. High-risk transcriptional profiles in multiple myeloma are an acquired feature that can occur in any subtype and more frequently with each subsequent relapse. [Extracted from the article]
- Published
- 2021
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39. Resilience: Now more than ever: This article belongs to Ambio's 50th Anniversary Collection. Theme: Anthropocene.
- Author
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Folke, Carl, Carpenter, Stephen, Elmqvist, Thomas, Gunderson, Lance, and Walker, Brian
- Subjects
BIOSPHERE ,COVID-19 pandemic - Abstract
10.1579/0044-7447(2007)36[639:CHANS]2.0.CO;2 20 Reyers B, Folke C, Moore M-L, Biggs R, Galaz V. Social-ecological systems resilience for navigating the dynamics of the Anthropocene. The topic resilience was selected as one of those and resulted in a 74 pages report 'Resilience and Sustainable Development: Building Adaptive Capacity in a World of Transformations' (Folke et al. [10]). The network engaged pioneering resilience thinkers and triggered interesting and path breaking work on resilience, including the by now classic Panarchy book edited by Gunderson and Holling in 2002. 10.1038/s41893-018-0210-1 7 Elmqvist T, Folke C, Nyström M, Peterson G, Bengtsson J, Walker B, Norberg J. Response diversity, ecosystem change, and resilience. [Extracted from the article]
- Published
- 2021
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40. Associations Between CYP17A1 and SERPINA6/A1 Polymorphisms, and Cardiometabolic Risk Factors in Black South Africans.
- Author
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Dlamini, Siphiwe N., Choudhury, Ananyo, Ramsay, Michèle, Micklesfield, Lisa K., Norris, Shane A., Crowther, Nigel J., Crawford, Andrew A., Walker, Brian R., Lombard, Zané, and Goedecke, Julia H.
- Subjects
BLACK South Africans ,LIQUID chromatography-mass spectrometry ,SOUTH Africans ,SINGLE nucleotide polymorphisms ,ADULTS ,BLOOD pressure - Abstract
Research in European and Asian populations has reported associations between single nucleotide polymorphisms (SNPs) in CYP17A1 and SERPINA6/A1 and circulating glucocorticoid concentrations, and some key cardiometabolic risk factors. This study aimed to investigate these associations in black South African adults, who are disproportionally affected by the metabolic syndrome and its related cardiometabolic risk factors. The dataset included black South African adults (n = 4,431; 56.7% women) from the AWI-Gen study, genotyped on the H3A genotyping array and imputed using the African reference panel at the Sanger imputation service. From the imputed data, 31 CYP17A1 SNPs and 550 SERPINA6/A1 SNPs were extracted. The metabolic syndrome and its components were defined using the 2009 harmonized guidelines. Serum glucocorticoid concentrations were measured in a subset of 304 men and 573 women, using a liquid chromatography-mass spectrometry method. Genetic associations were detected using PLINK. Bonferroni correction was used to control for multiple testing. A SNP at SERPINA6/A1 , rs17090691 (effect allele G), was associated with higher diastolic blood pressure (BP) in all adults combined (p = 9.47 × 10
−6 ). Sex-stratified analyses demonstrated an association between rs1051052 (effect allele G), another SERPINA6/A1 SNP, and higher high-density lipoprotein (HDL) cholesterol concentrations in women (p = 1.23 × 10−5 ). No association was observed between these variants and glucocorticoids or between any of the CYP17A1 SNPs and metabolic outcomes after adjusting for multiple testing. Furthermore, there were no associations between any of the SNPs tested and the metabolic syndrome. This study reports novel genetic associations between two SNPs at SERPINA6/A1 and key cardiometabolic risk factors in black South Africans. Future replication and functional studies in larger populations are required to confirm the role of the identified SNPs in the metabolic syndrome and assess if these associations are mediated by circulating glucocorticoids. [ABSTRACT FROM AUTHOR]- Published
- 2021
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41. Providing emotional and psychological support to nursing mothers through Chevron's response to the COVID-19 pandemic.
- Author
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Kashima, Sara, Walker, Brian, and Stephens, Angie
- Subjects
COVID-19 pandemic ,EMPLOYEE assistance programs ,MENTAL health personnel ,LACTATION consultants ,MOTHERS ,GROUPOIDS ,CONSULTANTS - Abstract
Chevron's internal Employee Assistance Program and WorkLife Services (EAP/WL) group is comprised of a team of 12 advisors who provide on-site mental health and worklife support for employees, dependents, and retirees across the enterprise. In response to the COVID-19 pandemic, EAP/WL implemented a virtual support group for the first time this year for nursing mothers. The program helps to meet the organizational need within the company, by providing a program that addresses the emotional needs of nursing mothers. The sessions were moderated by an internationally board-certified lactation consultant (IBCLC) with support from two employees: (1) a licensed mental health professional and (2) a worklife advisor. The employees were available to address any emotional and psychologically-related concerns raised by mothers during the monthly discussions. Strategies and best practices for developing a virtual support group for employees are described in this article. Sharing this program may assist other employers in implementing a similar program in support of their employees. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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42. Cryopreservation Preserves Cell-Type Composition and Gene Expression Profiles in Bone Marrow Aspirates From Multiple Myeloma Patients.
- Author
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Chen, Duojiao, Abu Zaid, Mohammad I., Reiter, Jill L., Czader, Magdalena, Wang, Lin, McGuire, Patrick, Xuei, Xiaoling, Gao, Hongyu, Huang, Kun, Abonour, Rafat, Walker, Brian A., and Liu, Yunlong
- Subjects
GENE expression profiling ,MULTIPLE myeloma ,BONE marrow ,RNA sequencing ,BONE marrow examination ,CELL populations - Abstract
Single-cell RNA sequencing reveals gene expression differences between individual cells and also identifies different cell populations that are present in the bulk starting material. To obtain an accurate assessment of patient samples, single-cell suspensions need to be generated as soon as possible once the tissue or sample has been collected. However, this requirement poses logistical challenges for experimental designs involving multiple samples from the same subject since these samples would ideally be processed at the same time to minimize technical variation in data analysis. Although cryopreservation has been shown to largely preserve the transcriptome, it is unclear whether the freeze-thaw process might alter gene expression profiles in a cell-type specific manner or whether changes in cell-type proportions might also occur. To address these questions in the context of multiple myeloma clinical studies, we performed single-cell RNA sequencing (scRNA-seq) to compare fresh and frozen cells isolated from bone marrow aspirates of six multiple myeloma patients, analyzing both myeloma cells (CD138
+ ) and cells constituting the microenvironment (CD138−). We found that cryopreservation using 90% fetal calf serum and 10% dimethyl sulfoxide resulted in highly consistent gene expression profiles when comparing fresh and frozen samples from the same patient for both CD138+ myeloma cells (R ≥ 0.96) and for CD138– cells (R ≥ 0.9). We also demonstrate that CD138– cell-type proportions showed minimal alterations, which were mainly related to small differences in immune cell subtype sensitivity to the freeze-thaw procedures. Therefore, when processing fresh multiple myeloma samples is not feasible, cryopreservation is a useful option in single-cell profiling studies. [ABSTRACT FROM AUTHOR]- Published
- 2021
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43. Identification of human glucocorticoid response markers using integrated multi- omic analysis from a randomized crossover trial.
- Author
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Chantzichristos, Dimitrios, Svensson, Per-Arne, Garner, Terence, Glad, Camilla A. M., Walker, Brian R., Bergthorsdottir, Ragnhildur, Ragnarsson, Oskar, Trimpou, Penelope, Stimson, Roland H., Borresen, Stina W., Feldt-Rasmussen, Ulla, Jansson, Per-Anders, Skrtic, Stanko, Stevens, Adam, and Johannsson, Gudmundur
- Published
- 2021
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44. Effects of Obesity and Insulin on Tissue-Specific Recycling Between Cortisol and Cortisone in Men.
- Author
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Anderson, Anna J., Andrew, Ruth, Homer, Natalie Z. M., Hughes, Katherine A., Boyle, Luke D., Nixon, Mark, Karpe, Fredrik, Stimson, Roland H., and Walker, Brian R.
- Subjects
CORTISONE ,GLUCOSE-6-phosphate dehydrogenase ,HYDROCORTISONE ,INSULIN ,ADIPOSE tissues ,SKELETAL muscle ,OBESITY ,ABDOMINAL adipose tissue ,GLUCOSE metabolism ,RESEARCH ,LIVER ,RESEARCH methodology ,HYPERINSULINISM ,MEDICAL cooperation ,EVALUATION research ,LEANNESS ,COMPARATIVE studies ,RANDOMIZED controlled trials ,IMMUNITY ,BODY mass index ,CROSSOVER trials - Abstract
Context: 11β-Hydroxysteroid dehydrogenase 1 (11βHSD1) reduces inert cortisone into active cortisol but also catalyzes reverse dehydrogenase activity. Drivers of cortisol/cortisone equilibrium are unclear. With obesity, 11βHSD1 transcripts are more abundant in adipose, but the consequences for oxidation vs reduction remain unknown.Objective: This work aimed to determine whether 11βHSD1 equilibrium in metabolic tissues is regulated by insulin and obesity.Methods: A 2-phase, randomized, crossover, single-blinded study in a clinical research facility was conducted of 10 lean and obese healthy men. 11β-Reductase and 11β-dehydrogenase activities were measured during infusion of 9,11,12,12-[2H]4-cortisol and 1,2-[2H]2-cortisone, respectively, on 2 occasions: once during saline infusion and once during a hyperinsulinemic-euglycemic clamp. Arterialized and venous samples were obtained across forearm skeletal muscle and abdominal subcutaneous adipose. Steroids were quantified by liquid chromatography-tandem mass spectrometry and adipose tissue transcripts by quantitative polymerase chain reaction.Results: Neither whole-body nor tissue-specific rates of production of cortisol or cortisone differed between lean and obese men, however insulin attenuated the diurnal decrease. Whole-body 11β-HSD1 reductase activity tended to be higher in obesity (~ 10%) and was further increased by insulin. Across adipose tissue, 11β-reductase activity was detected in obese individuals only and increased in the presence of insulin (18.99 ± 9.62 vs placebo 11.68 ± 3.63 pmol/100 g/minute; P < .05). Across skeletal muscle, 11β-dehydrogenase activity was reduced by insulin in lean men only (2.55 ± 0.90 vs 4.50 ± 1.42 pmol/100 g/minute, P < .05).Conclusions: Regeneration of cortisol is upregulated by insulin in adipose tissue but not skeletal muscle. In obesity, the equilibrium between 11β-reductase and 11β-dehydrogenase activities likely promotes cortisol accumulation in adipose, which may lead to adverse metabolic consequences. [ABSTRACT FROM AUTHOR]- Published
- 2021
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45. Monitoring treatment response and disease progression in myeloma with circulating cell‐free DNA.
- Author
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Deshpande, Shayu, Tytarenko, Ruslana G., Wang, Yan, Boyle, Eileen M., Ashby, Cody, Schinke, Carolina D., Thanendrarajan, Sharmilan, Zangari, Maurizio, Zhan, Fenghuang, Davies, Faith E., Morgan, Gareth J., van Rhee, Frits, and Walker, Brian A.
- Subjects
CIRCULATING tumor DNA ,DISEASE progression ,THERAPEUTICS ,GENE expression profiling ,PLASMACYTOMA ,MONOCLONAL gammopathies ,BIOMARKERS ,DNA - Abstract
Circulating cell‐free DNA (cfDNA) has the potential to capture spatial genetic heterogeneity in myeloma (MM) patients. We assessed whether cfDNA levels vary according to risk status defined by the 70 gene expression profile (GEP70). cfDNA levels in 77 patients were significantly higher in the GEP70 high‐risk (HR) group compared to the low‐risk (LR) group and correlated weakly with clinical markers including lactate dehydrogenase, β2‐microglobulin, and ISS. Patients with high cfDNA levels were associated with a worse PFS (hazard ratio 6.4; 95% CI of ratio 1.9‐22) and OS (hazard ratio 4.4; 95% CI of ratio 1.2‐15.7). Circulating tumor DNA (ctDNA) was elevated in the HR group and ctDNA correlated strongly with GEP70 risk score (Spearman r =.69, P =.0027). cfDNA concentrations were significantly elevated between days 3‐5 after chemotherapy before falling back to baseline levels. ctDNA in two patients showed a similar spike in levels between days 3 and 5 after chemotherapy with a concomitant increase in allele fraction of KRAS mutations. We assessed cfDNA levels in 25 patients with smoldering myeloma with serial samples and showed increased allele fraction of mutated KRAS at progression in cfDNA. Our study shows that cfDNA is a dynamic tool to capture genetic events in myeloma. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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46. KTP Laser Treatment of Early Glottic Cancer: A Multi-Institutional Retrospective Study.
- Author
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Parker, Noah P., Weidenbecher, Mark S., Friedman, Aaron D., Walker, Brian A., and Lott, David G.
- Subjects
GLOTTIS ,LARYNGEAL tumors ,MEDICAL lasers ,HEALTH outcome assessment ,RETROSPECTIVE studies ,DESCRIPTIVE statistics - Abstract
Objectives: The primary objectives were to report oncologic outcomes of transoral laser microsurgery with potassium-titanyl-phosphate (KTP) laser (TLM-KTP) ablation of early glottic cancer (EGC). The secondary objectives were to report vocal outcomes and to analyze factors that might influence outcomes. Methods: A multi-institutional, retrospective analysis of consecutive patients treated for T1 or T2 glottic squamous cell carcinoma undergoing TLM-KTP ablation with at least 2 years of follow-up was performed. Patients with prior radiation or surgery for laryngeal disease were excluded. Primary outcome measures included: surgical failures requiring radiation or laryngectomy, disease-specific survival (DSS), and overall survival (OS). Secondary outcome measures included: pre- and postoperative Voice Handicap Index-10 (VHI-10) scores. The effects of smoking status, stage, and anterior commissure involvement on outcomes were analyzed. Results: Overall 88 patients met inclusion criteria (83% male, 79.5% current or former smokers). Mean age was 68 (standard deviation (SD): 12). Mean follow-up was 39.5 months (SD: 15.3). Staging included 50 T1a, 21 T1b, and 20 T2 tumors, including three metachronous second primaries. Radiation and/or laryngectomy avoidance was achieved in 87/88 (98.9%) of patients, inclusive of 24 patients requiring KTP re-treatments. Two patients had biopsy-proven recurrence (2.3%), but only 21 of 24 re-treated patients received a formal biopsy. No patients died from laryngeal cancer. DSS and OS were 100% and 92.3%, respectively. The mean VHI-10 scores were 19.3 preoperatively, 3.8 at 6-months postop, and 3.8 at 2-years postop. Smokers had a longer interval to re-treatment (P =.03), patients with T2 lesions had a shorter interval to re-treatment (0.02), and patients with T2 lesions presented with worse initial VHI-10 scores (0.002). Conclusions: A multi-institutional, retrospective case series of TLM-KTP ablation of EGC demonstrated excellent oncologic outcomes when close surveillance and proactive re-treatments were utilized. Disease-specific survival, overall survival, and vocal function were excellent. Additional studies are necessary to further analyze the merits and risks of this treatment approach. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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- View/download PDF
47. Corridors of Clarity: Four Principles to Overcome Uncertainty Paralysis in the Anthropocene.
- Author
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Polasky, Stephen, Crépin, Anne-Sophie, Biggs, Reinette (Oonsie), Carpenter, Stephen R, Folke, Carl, Peterson, Garry, Scheffer, Marten, Barrett, Scott, Daily, Gretchen, Ehrlich, Paul, Howarth, Richard B, Hughes, Terry, Levin, Simon A, Shogren, Jason F, Troell, Max, Walker, Brian, and Xepapadeas, Anastasios
- Subjects
HEISENBERG uncertainty principle ,GLOBAL environmental change ,PARALYSIS ,AEROSOLS ,HUMAN constitution - Abstract
Global environmental change challenges humanity because of its broad scale, long-lasting, and potentially irreversible consequences. Key to an effective response is to use an appropriate scientific lens to peer through the mist of uncertainty that threatens timely and appropriate decisions surrounding these complex issues. Identifying such corridors of clarity could help understanding critical phenomena or causal pathways sufficiently well to justify taking policy action. To this end, we suggest four principles: Follow the strongest and most direct path between policy decisions on outcomes, focus on finding sufficient evidence for policy purpose, prioritize no-regrets policies by avoiding options with controversial, uncertain, or immeasurable benefits, aim for getting the big picture roughly right rather than focusing on details. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
48. An Introduction to S-Parameter Network Flow Diagrams.
- Author
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Walker, Brian
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FLOW charts ,TWO-port electric networks - Abstract
This article provides an introduction to S-parameter network flow diagrams and their application in solving real-world problems. The diagrams depict the flow of signals in different directions and account for reflections by adding arrows. The actual voltages are replaced with S-parameters, which represent the relative amplitude and phase of the voltages. The article explains how the diagrams can be manipulated using series, parallel, and fork rules to simplify the network. The use of network flow diagrams helps in understanding the function of S-parameter networks and is essential for interpreting calibration models. [Extracted from the article]
- Published
- 2023
49. An Introduction to the VNA and Vector Network Analysis: This article provides a brief tutorial on the vector network analyzer, how it works, and its application.
- Author
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Walker, Brian
- Subjects
VECTOR analysis ,REFLECTANCE ,SIGNAL generators ,ENGINEERS ,ELECTRIC lines - Abstract
This article provides an introduction to the vector network analyzer (VNA) and its applications. The VNA is a tool used to measure incident and reflected signals, allowing for the direct determination of reflection coefficients. It works by emitting an RF voltage wave and measuring how much of it is reflected and how much passes through the device under test (DUT). The VNA can be used to characterize the RF properties of a DUT and is a powerful tool for RF engineers. Copper Mountain Technologies offers a range of VNAs with different output frequencies. [Extracted from the article]
- Published
- 2023
50. Readers' Forum.
- Author
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Koshko, Rick Wiegmann, Black, Paul T., Lundgren, Kenneth, Walker, Brian, Mason, Dave, and Fitch, Ron
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STEREOPHONIC broadcasting ,RADIOS - Published
- 2024
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