Your browser doesn't support javascript.
loading
Montrer: 20 | 50 | 100
Résultats 1 - 20 de 103
Filtrer
1.
medRxiv ; 2024 Jul 23.
Article de Anglais | MEDLINE | ID: mdl-39108502

RÉSUMÉ

Background: Asthma, a complex respiratory disease, presents with inflammatory symptoms in the lungs, blood, and other tissues. We investigated the relationship between DNA methylation and 35 clinical markers of asthma. The Illumina Infinium EPIC v1 methylation array was used to evaluate 742,442 CpGs in whole blood samples from 319 participants. They were part of the Netherlands Twin Register from families with at least one member suffering from severe asthma. Repeat blood samples were taken after 10 years from 182 of these individuals. Principal component analysis (PCA) on the clinical markers yielded ten principal components (PCs) that explained 92.8% of the total variance. We performed epigenome-wide association studies (EWAS) for each of the ten PCs correcting for familial structure and other covariates. Results: 221 unique CpGs reached genome-wide significance at timepoint 1 (T1) after Bonferroni correction. PC7 accounted for the majority of associations (204), which correlated with loadings of eosinophil counts and immunoglobulin levels. Enrichment analysis via the EWAS Atlas identified 190 of these CpGs to be previously identified in EWASs of asthma and asthma-related traits. Proximity assessment to previously identified SNPs associated with asthma identified 17 unique SNPs within 1 MB of two of the 221 CpGs. EWAS in 182 individuals with epigenetic data at a second timepoint (T2) identified 49 significant CpGs. EWAS Atlas enrichment analysis indicated that 4 of the 49 were previously associated with asthma or asthma-related traits. Comparing the estimates of all the significant associations identified across the two time points (271 in total) yielded a correlation of 0.81. Conclusion: We identified 270 unique CpGs that were associated with PC scores generated from 35 clinical markers of asthma, either cross-sectionally or 10 years later. A strong correlation was present between effect sizes at the 2 timepoints. Most associations were identified for PC7, which captured blood eosinophil counts and immunoglobulin levels and many of these CpGs have previous associations in earlier studies of asthma and asthma-related traits. The results point to using this robust DNA methylation profile as a new, stable biomarker for asthma.

2.
Nurs Clin North Am ; 59(3): 345-358, 2024 Sep.
Article de Anglais | MEDLINE | ID: mdl-39059854

RÉSUMÉ

Simulation is a teaching and learning strategy that is used commonly in healthcare education in academia and practice settings. Nurses at the bedside may recall times in their formal education where simulation was used as a form of clinical learning or evaluation of their performance. It is possible that with the rise of nurse residency programs and in situ simulation that bedside nurses are experiencing simulation regularly within the workplace as a means of professional development. This article will set the stage for educators to develop high-quality simulation experiences.


Sujet(s)
Formation par simulation , Humains , Formation par simulation/méthodes , Compétence clinique/normes , Simulation sur patients standardisés , Enseignement infirmier/méthodes , Personnel infirmier hospitalier/enseignement et éducation , Lieu de travail/psychologie
3.
Cancers (Basel) ; 16(8)2024 Apr 20.
Article de Anglais | MEDLINE | ID: mdl-38672660

RÉSUMÉ

Breast cancer (BC) is a complex disease affecting one in eight women in the USA. Advances in population genomics have led to the development of polygenic risk scores (PRSs) with the potential to augment current risk models, but replication is often limited. We evaluated 2 robust PRSs with 313 and 3820 SNPs and the effects of multiple genotype imputation replications in BC cases and control populations. Biological samples from BC cases and cancer-free controls were drawn from three European ancestry cohorts. Genotyping on the Illumina Global Screening Array was followed by stringent quality control measures and 20 genotype imputation replications. A total of 468 unrelated cases and 4337 controls were scored, revealing significant differences in mean PRS percentiles between cases and controls (p < 0.001) for both SNP sets (313-SNP PRS: 52.81 and 48.07; 3820-SNP PRS: 55.45 and 49.81), with receiver operating characteristic curve analysis showing area under the curve values of 0.596 and 0.603 for the 313-SNP and 3820-SNP PRS, respectively. PRS fluctuations (from ~2-3% up to 9%) emerged across imputation iterations. Our study robustly reaffirms the predictive capacity of PRSs for BC by replicating their performance in an independent BC population and showcases the need to average imputed scores for reliable outcomes.

4.
Sci Adv ; 10(12): eadj8455, 2024 Mar 22.
Article de Anglais | MEDLINE | ID: mdl-38507497

RÉSUMÉ

Jupiter's moon Europa hosts a subsurface ocean under an ice shell of uncertain thickness. Europa has two multiring basins that exhibit several concentric rings. The formation of these multiring basins is thought to be sensitive to the thickness and thermal structure of the ice shell. Here, we simulate multiring basin forming impacts on Europa finding that a total ice shell greater than 20 kilometers thick is required to reproduce observed ring structures. Thin ice shells (<15 kilometers thick) result in compressional tectonics inconsistent with observed ring structures. Our simulations are also sensitive to the thermal structure of the ice shell and indicate that Europa's at least 20-kilometer ice shell is composed of a 6- to 8-kilometer-thick conductive lid overlying warm convecting ice. The constraints on Europa's ice shell structure resulting from this work are directly relevant to our understanding of the potential habitability of Europa.

5.
Plant Physiol ; 2024 Mar 02.
Article de Anglais | MEDLINE | ID: mdl-38431525

RÉSUMÉ

Engineering plant vegetative tissue to accumulate triacylglycerols (TAG, e.g., oil) can increase the amount of oil harvested per acre to levels that exceed current oilseed crops. Engineered tobacco (Nicotiana tabacum) lines that accumulate 15% to 30% oil of leaf dry weight resulted in starkly different metabolic phenotypes. In-depth analysis of the leaf lipid accumulation and 14CO2 tracking describe metabolic adaptations to the leaf oil engineering. An oil-for-membrane lipid tradeoff in the 15% oil line (referred to as HO) was surprisingly not further exacerbated when lipid production was enhanced to 30% (LEC2 line). The HO line exhibited a futile cycle that limited TAG yield through exchange with starch, altered carbon flux into various metabolite pools and end products, and suggested interference of the glyoxylate cycle with photorespiration that limited CO2 assimilation by 50%. In contrast, inclusion of the LEAFY COTYLEDON 2 (LEC2) transcription factor in tobacco improved TAG stability, alleviated the TAG-to-starch futile cycle, and recovered CO2 assimilation and plant growth comparable to wild type but with much higher lipid levels in leaves. Thus, the unstable production of storage reserves and futile cycling limit vegetative oil engineering approaches. The capacity to overcome futile cycles and maintain enhanced stable TAG levels in LEC2 demonstrated the importance of considering unanticipated metabolic adaptations while engineering vegetative oil crops.

6.
Article de Anglais | MEDLINE | ID: mdl-37914543

RÉSUMÉ

OBJECTIVES: We compared the effective dose (E) and thyroid equivalent dose of 2 extraoral bitewing (EOBW) units and compared E with their respective panoramic (PAN) modes and with intraoral bitewing radiography (IOBW). STUDY DESIGN: Child and adult anthropomorphic phantoms with dosimeters were used to evaluate Orthophos SL, Rayscan α+, and 1 intraoral unit using rectangular and circular collimation. Extraoral bitewing thyroid equivalent dose was assessed without and with thyroid shielding. RESULTS: Child and adult E values of EOBW were lower with Orthophos (3.6 and 8.6 µSv) than with Rayscan (28.1 and 30.2 µSv). For IOBW, E was lower with rectangular vs circular collimation for child (7.0 vs 11.8 µSv) and adult (4.6 vs 14.2 µSv). E values of EOBW were lower than PAN for Orthophos. The IOBW E was lower than Rayscan EOBW for child (≤11.8 vs 28.1 µSv) and adult (≤14.2 vs 30.2 µSv). Adult E for rectangular IOBW (4.6 µSv) was lower than EOBW with Orthophos (8.6 µSv) and Rayscan (30.2 µSv). Thyroid shielding reduced EOBW thyroid equivalent dose with Rayscan in the adult from 190.7 to 89.0 µSv. CONCLUSION: Orthophos provides significantly lower EOBW E than Rayscan, thus EOBW recommendations must be unit specific. For children, Orthophos EOBW could be an alternative to IOBW, for which rectangular collimation is recommended. Thyroid shielding reduced adult Rayscan equivalent dose but added imaging artifacts.


Sujet(s)
Radioprotection , Adulte , Enfant , Humains , Radiographie panoramique , Radiographie rétrocoronaire , Dose de rayonnement , Glande thyroide/imagerie diagnostique , Fantômes en imagerie
7.
Int J Mol Sci ; 24(19)2023 Sep 27.
Article de Anglais | MEDLINE | ID: mdl-37834090

RÉSUMÉ

The field of DNA methylation research is rapidly evolving, focusing on disease and phenotype changes over time using methylation measurements from diverse tissue sources and multiple array platforms. Consequently, identifying the extent of longitudinal, inter-tissue, and inter-platform variation in DNA methylation is crucial for future advancement. DNA methylation was measured in 375 individuals, with 197 of those having 2 blood sample measurements ~10 years apart. Whole-blood samples were measured on Illumina Infinium 450K and EPIC methylation arrays, and buccal samples from a subset of 58 participants were measured on EPIC array. The data were analyzed with the aims to examine the correlation between methylation levels in longitudinal blood samples in 197 individuals, examine the correlation between methylation levels in the blood and buccal samples in 58 individuals, and examine the correlation between blood methylation profiles assessed on the EPIC and 450K arrays in 83 individuals. We identified 136,833, 7674, and 96,891 CpGs significantly and strongly correlated (>0.50) longitudinally, across blood and buccal samples as well as array platforms, respectively. A total of 3674 of these CpGs were shared across all three sets. Analysis of these shared CpGs identified previously found associations with aging, ancestry, and 7016 mQTLs as well.


Sujet(s)
Vieillissement , Méthylation de l'ADN , Humains , Études transversales , Ilots CpG , Épigenèse génétique
8.
S D Med ; 76(6): 248-256, 2023 Jun.
Article de Anglais | MEDLINE | ID: mdl-37732913

RÉSUMÉ

INTRODUCTION: During the coronavirus disease 2019 (COVID-19) pandemic, real-time reverse transcription polymerase chain reaction (RT-PCR) became an essential tool for laboratories to provide high-sensitivity qualitative diagnostic testing for patients and real-time data to public health officials. Here we explore the predictive value of quantitative data from RT-PCR cycle threshold (Ct) values in epidemiological measures, symptom presentation, and variant transition. METHODS: To examine the association with hospitalizations and deaths, data from 74,479 patients referred to the Avera Institute for Human Genetics (AIHG) for COVID-19 testing in 2020 were matched by calendar week to epidemiological data reported by the South Dakota Department of Health. We explored the association between symptom data, patient age, and Ct values for 101 patients. We also explored changes in Ct values during variant transition detected by genomic surveillance sequencing of the AIHG testing population during 2021. RESULTS: Measures from AIHG diagnostic testing strongly explain variance in the South Dakota state positivity percentage (R2 = 0.758), a two-week delay in hospitalizations (R2 = 0.856), and a four-week delay in deaths (R2 = 0.854). Based on factor analysis of patient symptoms, three groups could be distinguished which had different presentations of age, Ct value, and time from collection. Additionally, conflicting Ct value results among SARSCoV- 2 variants during variant transition may reflect the community transmission dynamics. CONCLUSIONS: Measures of Ct value in RT-PCR diagnostic assays combined with routine screening have valuable applications in monitoring the dynamics of SARS-CoV-2 within communities.


Sujet(s)
COVID-19 , SARS-CoV-2 , Humains , SARS-CoV-2/génétique , COVID-19/diagnostic , COVID-19/épidémiologie , Dépistage de la COVID-19 , Hospitalisation , Pandémies
9.
Child Adolesc Psychiatr Clin N Am ; 32(4): 815-837, 2023 10.
Article de Anglais | MEDLINE | ID: mdl-37739637

RÉSUMÉ

Transgender children and adolescents are at an elevated risk for negative mental health outcomes due to exposure to stigma and discrimination regarding their identity. While various environments may perpetuate this stigma, many supports also exist that can bolster safety, affirmation, and resilience in this population. Opportunities for support exist within schools, broader communities, religious organizations, and with medical professionals who practice gender-affirming care. Clinicians who are familiar with resources in their communities can effectively guide transgender youth and their families to these affirming spaces.


Sujet(s)
Personnes transgenres , Enfant , Humains , Adolescent , Stigmate social
10.
Nurs Educ Perspect ; 44(6): E33-E38, 2023.
Article de Anglais | MEDLINE | ID: mdl-37493400

RÉSUMÉ

AIM: This study evaluated the impact of a single dose of training in Debriefing for Meaningful Learning (DML) on learner knowledge outcomes and time spent in debriefing. BACKGROUND: Regulatory bodies recommend that faculty who debrief receive training and competence assessment to ensure positive student learning outcomes, yet there is little literature describing the training needed. There is also little understanding of the impact of a single training on the length of debriefing, debriefer skill, and learner outcomes. METHOD: Following training, debriefers submitted a recorded debriefing for assessment by experts; their learners completed knowledge assessment tests at three time points. RESULTS: Longer debriefing time led to higher DML Evaluation Scale scores. Learner knowledge scores improved and later decayed. CONCLUSION: The results of this study contribute to the evidence about the importance of training to debrief well, the impact of training on the length of debriefing time, and subsequent learner outcomes.

11.
Nurse Educ ; 48(6): 321-325, 2023.
Article de Anglais | MEDLINE | ID: mdl-37130198

RÉSUMÉ

BACKGROUND: The assignment to be an observer in simulation is common. Despite evidence that learning outcomes are similar for participants and observers, there is uncertainty among simulation facilitators about how to create a valuable learning experience for learners in observer roles. PROBLEM: The prebriefing practices of establishing a fiction contract and orienting learners to their role are frequently centered on learners in participant roles. APPROACH: Tailoring a fiction contract to the opportunities and challenges that observers experience as well as the use of feedforward to provide specific objectives to learners in observer roles is discussed. CONCLUSIONS: Including specific strategies in the prebriefing for learners in observer roles sets observers up for success in simulation learning experiences.


Sujet(s)
Compétence clinique , Apprentissage , Humains , Recherche en enseignement des soins infirmiers , Simulation sur patients standardisés
12.
Nurse Educ ; 48(5): 254-259, 2023.
Article de Anglais | MEDLINE | ID: mdl-37000866

RÉSUMÉ

BACKGROUND: Learning to effectively debrief with student learners can be a challenging task. Currently, there is little evidence to support the best way to train and evaluate a debriefer's competence with a particular debriefing method. PURPOSE: The purpose of this study was to develop and test an asynchronous online distributed modular training program with repeated doses of formative feedback to teach debriefers how to implement Debriefing for Meaningful Learning (DML). METHODS: Following the completion of an asynchronous distributed modular training program, debriefers self-evaluated their debriefing and submitted a recorded debriefing for expert evaluation and feedback using the DML Evaluation Scale (DMLES). RESULTS: Most debriefers were competent in DML debriefing after completing the modular training at time A, with DMLES scores increasing with each debriefing submission. CONCLUSION: The results of this study support the use of an asynchronous distributed modular training program for teaching debriefers how to implement DML.


Sujet(s)
Compétence clinique , Formation par simulation , Humains , Rétroaction , Recherche en enseignement des soins infirmiers , Apprentissage , Rétroaction formative
13.
Nature ; 610(7931): 373-380, 2022 10.
Article de Anglais | MEDLINE | ID: mdl-36198789

RÉSUMÉ

An immunosuppressive tumour microenvironment is a major obstacle in the control of pancreatic and other solid cancers1-3. Agonists of the stimulator of interferon genes (STING) protein trigger inflammatory innate immune responses to potentially overcome tumour immunosuppression4. Although these agonists hold promise as potential cancer therapies5, tumour resistance to STING monotherapy has emerged in clinical trials and the mechanism(s) is unclear5-7. Here we show that the administration of five distinct STING agonists, including cGAMP, results in an expansion of human and mouse interleukin (IL)-35+ regulatory B cells in pancreatic cancer. Mechanistically, cGAMP drives expression of IL-35 by B cells in an IRF3-dependent but type I interferon-independent manner. In several preclinical cancer models, the loss of STING signalling in B cells increases tumour control. Furthermore, anti-IL-35 blockade or genetic ablation of IL-35 in B cells also reduces tumour growth. Unexpectedly, the STING-IL-35 axis in B cells reduces proliferation of natural killer (NK) cells and attenuates the NK-driven anti-tumour response. These findings reveal an intrinsic barrier to systemic STING agonist monotherapy and provide a combinatorial strategy to overcome immunosuppression in tumours.


Sujet(s)
Lymphocytes B régulateurs , Cellules tueuses naturelles , Tumeurs , Animaux , Lymphocytes B régulateurs/immunologie , Humains , Immunité innée/immunologie , Immunothérapie , Facteur-3 de régulation d'interféron , Interféron de type I/immunologie , Interleukines/antagonistes et inhibiteurs , Cellules tueuses naturelles/immunologie , Protéines membranaires/agonistes , Protéines membranaires/métabolisme , Souris , Tumeurs/traitement médicamenteux , Tumeurs/immunologie , Nucléotides cycliques/métabolisme , Microenvironnement tumoral
14.
Nat Commun ; 13(1): 4817, 2022 08 16.
Article de Anglais | MEDLINE | ID: mdl-35974008

RÉSUMÉ

NASA's Gravity Recovery and Interior Laboratory (GRAIL) spacecraft revealed the crust of the Moon is highly porous, with ~4% porosity at 20 km deep. The deep lying porosity discovered by GRAIL has been difficult to explain, with most current models only able to explain high porosity near the lunar surface (first few kilometers) or inside complex craters. Using hydrocode routines we simulated fracturing and generation of porosity by large impacts in lunar, martian, and Earth crust. Our simulations indicate impacts that produce 100-1000 km scale basins alone are capable of producing all observed porosity within the lunar crust. Simulations under the higher surface gravity of Mars and Earth suggest basin forming impacts can be a primary source of porosity and fracturing of ancient planetary crusts. Thus, we show that impacts could have supported widespread crustal fluid circulation, with important implications for subsurface habitable environments on early Earth and Mars.


Sujet(s)
Environnement extraterrestre , Mars , , Lune , Porosité
15.
Function (Oxf) ; 3(4): zqac033, 2022.
Article de Anglais | MEDLINE | ID: mdl-35910331

RÉSUMÉ

Cannabis sativa has long been known to affect numerous biological activities. Although plant extracts, purified cannabinoids, or synthetic cannabinoid analogs have shown therapeutic potential in pain, inflammation, seizure disorders, appetite stimulation, muscle spasticity, and treatment of nausea/vomiting, the underlying mechanisms of action remain ill-defined. In this study we provide the first comprehensive overview of the effects of whole-plant Cannabis extracts and various pure cannabinoids on store-operated calcium (Ca2+) entry (SOCE) in several different immune cell lines. Store-operated Ca2+ entry is one of the most significant Ca2+ influx mechanisms in immune cells, and it is critical for the activation of T lymphocytes, leading to the release of proinflammatory cytokines and mediating inflammation and T cell proliferation, key mechanisms for maintaining chronic pain. While the two major cannabinoids cannabidiol and trans-Δ9-tetrahydrocannabinol were largely ineffective in inhibiting SOCE, we report for the first time that several minor cannabinoids, mainly the carboxylic acid derivatives and particularly cannabigerolic acid, demonstrated high potency against SOCE by blocking calcium release-activated calcium currents. Moreover, we show that this inhibition of SOCE resulted in a decrease of nuclear factor of activated T-cells activation and Interleukin 2 production in human T lymphocytes. Taken together, these results indicate that cannabinoid-mediated inhibition of a proinflammatory target such as SOCE may at least partially explain the anti-inflammatory and analgesic effects of Cannabis.


Sujet(s)
Cannabinoïdes , Cytokines , Humains , Cytokines/métabolisme , Calcium/métabolisme , Cannabinoïdes/pharmacologie , Signalisation calcique , Inflammation/traitement médicamenteux
16.
J Contin Educ Nurs ; 53(7): 321-327, 2022 Jul.
Article de Anglais | MEDLINE | ID: mdl-35858149

RÉSUMÉ

Debriefing for Meaningful Learning (DML) is a method of debriefing grounded in the theory of reflection used following a simulation or clinical learning experience to engage participants in an interactive dialogue aimed at examining and evaluating their thinking and decision-making processes. With increasing adoption of DML worldwide, a sustainable training program for nurse educators is needed. Attending conferences and workshops that provide training is challenging for many nurse educators because of time and cost constraints. One promising solution is the train-the-trainer (TTT) model. In this article, the development and implementation of a TTT model of DML debriefer training, adaptable to both academic and clinical nursing professional development, is described. [J Contin Educ Nurs. 2022;53(7):321-327.].


Sujet(s)
Formation au diplôme infirmier (USA) , Formation par simulation , Compétence clinique , Formation au diplôme infirmier (USA)/méthodes , Corps enseignant et administratif de l'école d'infirmières , Humains , Apprentissage , Simulation sur patients standardisés
17.
Cytokine ; 156: 155892, 2022 08.
Article de Anglais | MEDLINE | ID: mdl-35653895

RÉSUMÉ

The intestinal mucosa protects the body from physical damage, pathogens, and antigens. However, inflammatory bowel diseases (IBDs) patients suffer from poor mucosal tissue function, including the lack of an effective cellular and/or mucus barrier. We investigated the mucus producing human colonic epithelial cell line HT29-MTX E12 to study its suitability as an in vitro model of cell/mucus barrier adaption during IBD. It was found that the proinflammatory cytokine interferon-gamma (IFN-γ), but not tumor necrosis factor-alpha (TNF-α), reduced cell viability. IFN-γ and TNF-α were found to synergize to decrease barrier function, as measured by trans-epithelial electric resistance (TER) and molecular flux assays. Cells cultured under an air-liquid interface produced an adherent mucus layer, and under these conditions reduced barrier function was found after cytokine exposure. Furthermore, IFN-γ, but not TNF-α treatment, upregulated the IFN-γ receptor 1 (IFNGR1) and TNF-α receptor super family 1A (TNFRSF1A) subunit mRNA in vitro. Co-stimulation resulted in increased mRNA expression of CLDN 2 and 5, two gene known to play a role in epithelial barrier integrity. Analysis of IBD patient samples revealed IFNGR1 and TNFRSF mRNA increased coincidently with guanylate binding protein 1 (GBP1) expression, an indicator of NFkB activity. Lastly, CLDN2 was found at higher levels in IBD patients while HNF4a was suppressed with disease. In conclusion, IFN-γ and TNF-α degrade epithelial/mucus barriers coincident with changes in CLDN gene and cytokine receptor subunit mRNA expression in HT29-MTX E12 cells. These changes largely reflect those observed in IBD patient samples.


Sujet(s)
Maladies inflammatoires intestinales , Interféron gamma , Cytokines/métabolisme , Cellules HT29 , Humains , Interféron gamma/métabolisme , Interféron gamma/pharmacologie , Muqueuse intestinale/métabolisme , Protéines de transport de la membrane mitochondriale/métabolisme , ARN messager/génétique , ARN messager/métabolisme , Récepteurs aux cytokines/métabolisme , Récepteur interféron/métabolisme , Récepteurs aux facteurs de nécrose tumorale/métabolisme , Récepteur au facteur de nécrose tumorale de type I/génétique , Récepteur au facteur de nécrose tumorale de type I/métabolisme , Facteur de nécrose tumorale alpha/métabolisme ,
18.
Sci Adv ; 8(14): eabm8475, 2022 Apr 08.
Article de Anglais | MEDLINE | ID: mdl-35394845

RÉSUMÉ

The formation of the largest and most ancient lunar impact basin, South Pole-Aitken (SPA), was a defining event in the Moon's evolution. Using numerical simulations, we show that widespread mantle heating from the SPA impact can catalyze the formation of the long-lived nearside-farside lunar asymmetry in incompatible elements and surface volcanic deposits, which has remained unexplained since its discovery in the Apollo era. The impact-induced heat drives hemisphere-scale mantle convection, which would sequester Th- and Ti-rich lunar magma ocean cumulates in the nearside hemisphere within a few hundred million years if they remain immediately beneath the lunar crust at the time of the SPA impact. A warm initial upper mantle facilitates generation of a pronounced compositional asymmetry consistent with the observed lunar asymmetry.

19.
Sci Adv ; 8(10): eabm2434, 2022 Mar 11.
Article de Anglais | MEDLINE | ID: mdl-35263140

RÉSUMÉ

The ~31-km-wide Hiawatha structure, located beneath Hiawatha Glacier in northwestern Greenland, has been proposed as an impact structure that may have formed after the Pleistocene inception of the Greenland Ice Sheet. To date the structure, we conducted 40Ar/39Ar analyses on glaciofluvial sand and U-Pb analyses on zircon separated from glaciofluvial pebbles of impact melt rock, all sampled immediately downstream of Hiawatha Glacier. Unshocked zircon in the impact melt rocks dates to ~1915 million years (Ma), consistent with felsic intrusions found in local bedrock. The 40Ar/39Ar data indicate Late Paleocene resetting and shocked zircon dates to 57.99 ± 0.54 Ma, which we interpret as the impact age. Consequently, the Hiawatha impact structure far predates Pleistocene glaciation and is unrelated to either the Paleocene-Eocene Thermal Maximum or flood basalt volcanism in east Greenland. However, it was contemporaneous with the Paleocene Carbon Isotope Maximum, although the impact's exact paleoenvironmental and climatic significance awaits further investigation.

20.
Cells ; 10(6)2021 06 13.
Article de Anglais | MEDLINE | ID: mdl-34199280

RÉSUMÉ

Multiple myeloma (MM) is a currently incurable hematologic cancer. Patients that initially respond to therapeutic intervention eventually relapse with drug resistant disease. Thus, novel treatment strategies are critically needed to improve patient outcomes. Our group has developed a novel cyclic peptide referred to as MTI-101 for the treatment of MM. We previously reported that acquired resistance to HYD-1, the linear form of MTI-101, correlated with the repression of genes involved in store operated Ca2+ entry (SOCE): PLCß, SERCA, ITPR3, and TRPC1 expression. In this study, we sought to determine the role of TRPC1 heteromers in mediating MTI-101 induced cationic flux. Our data indicate that, consistent with the activation of TRPC heteromers, MTI-101 treatment induced Ca2+ and Na+ influx. However, replacing extracellular Na+ with NMDG did not reduce MTI-101-induced cell death. In contrast, decreasing extracellular Ca2+ reduced both MTI-101-induced Ca2+ influx as well as cell death. The causative role of TRPC heteromers was established by suppressing STIM1, TRPC1, TRPC4, or TRPC5 function both pharmacologically and by siRNA, resulting in a reduction in MTI-101-induced Ca2+ influx. Mechanistically, MTI-101 treatment induces trafficking of TRPC1 to the membrane and co-immunoprecipitation studies indicate that MTI-101 treatment induces a TRPC1-STIM1 complex. Moreover, treatment with calpeptin inhibited MTI-101-induced Ca2+ influx and cell death, indicating a role of calpain in the mechanism of MTI-101-induced cytotoxicity. Finally, components of the SOCE pathway were found to be poor prognostic indicators among MM patients, suggesting that this pathway is attractive for the treatment of MM.


Sujet(s)
Signalisation calcique/effets des médicaments et des substances chimiques , Myélome multiple/métabolisme , Protéines tumorales/métabolisme , Peptides cycliques/pharmacologie , Canaux cationiques TRPC/métabolisme , Mort cellulaire/effets des médicaments et des substances chimiques , Lignée cellulaire tumorale , Humains , Myélome multiple/anatomopathologie , Transport des protéines/effets des médicaments et des substances chimiques
SÉLECTION CITATIONS
DÉTAIL DE RECHERCHE