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1.
Proc Natl Acad Sci U S A ; 120(20): e2219083120, 2023 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-37155883

RESUMO

Due to their low viscosity, high mobility, and high element contents, supercritical fluids are important agents in the cycling of elements. However, the chemical composition of supercritical fluids in natural rocks is poorly understood. Here, we investigate well-preserved primary multiphase fluid inclusions (MFIs) from an ultrahigh-pressure (UHP) metamorphic vein of the Bixiling eclogite in Dabieshan, China, thus providing direct evidence for the components of supercritical fluid occurring in a natural system. Via the 3D modeling of MFIs by Raman scanning, we quantitatively determined the major composition of the fluid trapped in the MFIs. Combined with the peak-metamorphic pressure-temperature conditions and the cooccurrence of coesite, rutile, and garnet, we suggest that the trapped fluids in the MFIs represent supercritical fluids in a deep subduction zone. The strong mobility of the supercritical fluids with respect to carbon and sulfur suggests that such fluids have profound effects on global carbon and sulfur cycling.

2.
Cell Mol Life Sci ; 81(1): 182, 2024 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-38615283

RESUMO

BACKGROUND: Stem cell therapy is a promising therapeutic strategy. In a previous study, we evaluated tumorigenicity by the stereotactic transplantation of neural stem cells (NSCs) and embryonic stem cells (ESCs) from experimental mice. Twenty-eight days later, there was no evidence of tumor formation or long-term engraftment in the NSCs transplantation group. In contrast, the transplantation of ESCs caused tumor formation; this was due to their high proliferative capacity. Based on transcriptome sequencing, we found that a long intergenic non-coding RNA (named linc-NSC) with unknown structure and function was expressed at 1100-fold higher levels in NSCs than in ESCs. This finding suggested that linc-NSC is negatively correlated with stem cell pluripotency and tumor development, but positively correlated with neurogenesis. In the present study, we investigated the specific role of linc-NSC in NSCs/ESCs in tumor formation and neurogenesis. METHODS: Whole transcriptome profiling by RNA sequencing and bioinformatics was used to predict lncRNAs that are widely associated with enhanced tumorigenicity. The expression of linc-NSC was assessed by quantitative real-time PCR. We also performed a number of in vitro methods, including cell proliferation assays, differentiation assays, immunofluorescence assays, flow cytometry, along with in vivo survival and immunofluorescence assays to investigate the impacts of linc-NSC on tumor formation and neurogenesis in NSCs and ESCs. RESULTS: Following the knockdown of linc-NSC in NSCs, NSCs cultured in vitro and those transplanted into the cortex of mice showed stronger survival ability (P < 0.0001), enhanced proliferation(P < 0.001), and reduced apoptosis (P < 0.05); the opposite results were observed when linc-NSC was overexpressed in ESCs. Furthermore, the overexpression of linc-NSC in ECSs induced enhanced apoptosis (P < 0.001) and differentiation (P < 0.01), inhibited tumorigenesis (P < 0.05) in vivo, and led to a reduction in tumor weight (P < 0.0001). CONCLUSIONS: Our analyses demonstrated that linc-NSC, a promising gene-edited target, may promote the differentiation of mouse NSCs and inhibit tumorigenesis in mouse ESCs. The knockdown of linc-NSC inhibited the apoptosis in NSCs both in vitro and in vivo, and prevented tumor formation, revealing a new dimension into the effect of lncRNA on low survival NSCs and providing a prospective gene manipulation target prior to transplantation. In parallel, the overexpression of linc-NSC induced apoptosis in ESCs both in vitro and in vivo and attenuated the tumorigenicity of ESCs in vivo, but did not completely prevent tumor formation.


Assuntos
Células-Tronco Embrionárias , Células-Tronco Neurais , Animais , Camundongos , Estudos Prospectivos , Diferenciação Celular/genética , Carcinogênese/genética , Transformação Celular Neoplásica , Apoptose/genética , Proliferação de Células/genética
3.
Nucleic Acids Res ; 51(7): 3270-3287, 2023 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-36864746

RESUMO

Many prokaryotic viruses are temperate and their reactivation is tightly regulated. However, except for a few bacterial model systems, the regulatory circuits underlying the exit from lysogeny are poorly understood, especially in archaea. Here, we report a three-gene module which regulates the switch between lysogeny and replicative cycle in a haloarchaeal virus SNJ2 (family Pleolipoviridae). The SNJ2 orf4 encodes a winged helix-turn-helix DNA binding protein which maintains lysogeny through repressing the expression of the viral integrase gene intSNJ2. To switch to the induced state, two other SNJ2-encoded proteins, Orf7 and Orf8, are required. Orf8 is a homolog of cellular AAA+ ATPase Orc1/Cdc6, which is activated upon mitomycin C-induced DNA damage, possibly through posttranslational modification. Activated Orf8 initiates the expression of Orf7 which, in turn, antagonizes the function of Orf4, leading to the transcription of intSNJ2, thereby switching SNJ2 to the induced state. Comparative genomics analysis revealed that the SNJ2-like Orc1/Cdc6-centered three-gene module is common in haloarchaeal genomes, always present in the context of integrated proviruses. Collectively, our results uncover the first DNA damage signaling pathway encoded by a temperate archaeal virus and reveal an unexpected role of the widely distributed virus-encoded Orc1/Cdc6 homologs.


Assuntos
Lisogenia , Vírus , Lisogenia/genética , Vírus/genética , Provírus/genética , Vírus de DNA/genética , DNA Viral/genética , Dano ao DNA , Transdução de Sinais/genética
4.
Proc Natl Acad Sci U S A ; 119(4)2022 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-35058365

RESUMO

NMR chemical shifts provide detailed information on the chemical properties of molecules, thereby complementing structural data from techniques like X-ray crystallography and electron microscopy. Detailed analysis of protein NMR data, however, often hinges on comprehensive, site-specific assignment of backbone resonances, which becomes a bottleneck for molecular weights beyond 40 to 45 kDa. Here, we show that assignments for the (2x)72-kDa protein tryptophan synthase (665 amino acids per asymmetric unit) can be achieved via higher-dimensional, proton-detected, solid-state NMR using a single, 1-mg, uniformly labeled, microcrystalline sample. This framework grants access to atom-specific characterization of chemical properties and relaxation for the backbone and side chains, including those residues important for the catalytic turnover. Combined with first-principles calculations, the chemical shifts in the ß-subunit active site suggest a connection between active-site chemistry, the electrostatic environment, and catalytically important dynamics of the portal to the ß-subunit from solution.


Assuntos
Cristalografia por Raios X , Modelos Moleculares , Ressonância Magnética Nuclear Biomolecular , Conformação Proteica , Triptofano Sintase/química , Cristalografia por Raios X/métodos , Peso Molecular , Ressonância Magnética Nuclear Biomolecular/métodos , Ligação Proteica , Multimerização Proteica
5.
Am J Physiol Cell Physiol ; 327(1): C1-C10, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38708521

RESUMO

The purpose of this study is to investigate the previously unknown connection that succinate has with neutrophils in the setting of adjuvant-mediated immunological enhancement. It has been discovered that succinates stimulate the recruitment of neutrophils in immunization sites, which in turn induces the expression of what is known as neutrophil-derived B cell-activating factor (BAFF). Further amplification of vaccine-induced antibody responses is provided via the succinate receptor 1-interferon regulatory factor 5 (SUCNR1-IRF5)-BAFF signaling pathway, which provides insights into a unique mechanism for immunological enhancement.NEW & NOTEWORTHY This study explores the role of succinate as a vaccine adjuvant, revealing its capacity to enhance neutrophil recruitment at immunization sites, which boosts B cell activation through the succinate receptor 1-interferon regulatory factor 5-B cell-activating factor (SUCNR1-IRF5-BAFF) signaling pathway. Results demonstrate succinate's potential to amplify vaccine-induced antibody responses, highlighting its significance in immunological enhancement and offering new insights into the adjuvant mechanisms of action, particularly in neutrophil-mediated immune responses.


Assuntos
Adjuvantes Imunológicos , Neutrófilos , Transdução de Sinais , Ácido Succínico , Neutrófilos/imunologia , Neutrófilos/metabolismo , Animais , Ácido Succínico/metabolismo , Adjuvantes Imunológicos/farmacologia , Humanos , Camundongos , Linfócitos B/imunologia , Linfócitos B/metabolismo , Linfócitos B/efeitos dos fármacos , Infiltração de Neutrófilos/efeitos dos fármacos , Fator Ativador de Células B/metabolismo , Fator Ativador de Células B/imunologia , Fator Ativador de Células B/genética , Camundongos Endogâmicos C57BL , Feminino
6.
J Am Chem Soc ; 146(14): 9967-9974, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38441882

RESUMO

Nanoscale defect engineering plays a crucial role in incorporating extraordinary catalytic properties in two-dimensional materials by varying the surface groups or site interactions. Herein, we synthesized high-loaded nitrogen-doped Boridene (N-Boridene (Mo4/3(BnN1-n)2-mTz), N-doped concentration up to 26.78 at %) nanosheets by chemical exfoliation followed by cyanamide intercalation. Three different nitrogen sites are observed in N-Boridene, wherein the site of boron vacancy substitution mainly accounts for its high chemical activity. Attractively, as a cathode for Mg-CO2 batteries, it delivers a long-term lifetime (305 cycles), high-energy efficiency (93.6%), and ultralow overpotential (∼0.09 V) at a high current of 200 mA g-1, which overwhelms all Mg-CO2 batteries reported so far. Experimental and computational studies suggest that N-Boridene can remarkably change the adsorption energy of the reaction products and lower the energy barrier of the rate-determining step (*MgCO2 → *MgCO3·xH2O), resulting in the rapid reversible formation/decomposition of new MgCO3·5H2O products. The surging Boridene materials with defects provide substantial opportunities to develop other heterogeneous catalysts for efficient capture and converting of CO2.

7.
J Am Chem Soc ; 146(12): 8508-8519, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38382542

RESUMO

Tricomponent cobalt(salen)-catalyzed carbofunctionalization of unsaturated substrates by radical-polar crossover has the potential to streamline access to broad classes of heteroatom-functionalized synthetic targets, yet the reaction platform has remained elusive, despite the well-developed analogous hydrofunctionalizations mediated by high-valent alkylcobalt intermediates. We report herein the development of a cobalt(salen) catalytic system that enables carbofunctionalization. The reaction entails a tricomponent decarboxylative 1,4-carboamination of dienes and provides a direct route to aromatic allylic amines by obviating preformed allylation reagents and protection of oxidation-sensitive aromatic amines. The catalytic system merges acridine photocatalysis with cobalt(salen)-catalyzed regioselective 1,4-carbofunctionalization that facilitates the crossover of the radical and polar phases of the tricomponent coupling process, revealing critical roles of the reactants, as well as ligand effects and the nature of the formal high-valent alkylcobalt species on the chemo- and regioselectivity.

8.
Biol Chem ; 405(2): 129-141, 2024 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-36857196

RESUMO

Hepatic metastasis is a major cause of colorectal cancer (CRC)-related deaths. Presently, the role of long non-coding RNAs (lncRNAs) in hepatic metastases from CRC is elusive. We dissected possible interplay between LINC00858/miR-132-3p/IGF2BP1 via bioinformatics approaches. Subsequently we analyzed mRNA expression of LINC00858, miR-132-3p and IGF2BP1 through qRT-PCR. Western blot was used to detect protein expression of IGF2BP1. RNA immunoprecipitation chip and dual-luciferase assay validated interaction between LINC00858 and miR-132-3p, as well as miR-132-3p and IGF2BP1. Cell viability, invasion, and migration were examined via CCK-8, colony formation, transwell and wound healing assays. Effect of LINC00858 on CRC hepatic metastases was validated via in vivo assay. Upregulated LINC00858 and IGF2BP1, and downregulated miR-132-3p were predicted in tumor tissues of patients with hepatic metastases from CRC. There were targeting relationships between LINC00858 and miR-132-3p, as well as miR-132-3p and IGF2BP1. Besides, LINC00858 facilitated progression of CRC cells. Rescue assay suggested that silencing LINC00858 suppressed CRC cell progression, while further silencing miR-132-3p or overexpressing IGF2BP1 reversed such effects. LINC00858 could facilitate CRC tumor growth and hepatic metastases. LINC00858 induced CRC hepatic metastases via regulating miR-132-3p/ IGF2BP1, and this study may deliver a new diagnostic marker for the disease.


Assuntos
Neoplasias Colorretais , Neoplasias Hepáticas , MicroRNAs , RNA Longo não Codificante , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Linhagem Celular Tumoral , Neoplasias Colorretais/patologia , Proliferação de Células/genética , Movimento Celular/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas/genética , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo
9.
Nat Methods ; 18(8): 893-902, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34312566

RESUMO

Complex biological processes such as embryogenesis require precise coordination of cell differentiation programs across both space and time. Using protein-fusion fluorescent reporters and four-dimensional live imaging, we present a protein expression atlas of transcription factors (TFs) mapped onto developmental cell lineages during Caenorhabditis elegans embryogenesis, at single-cell resolution. This atlas reveals a spatiotemporal combinatorial code of TF expression, and a cascade of lineage-specific, tissue-specific and time-specific TFs that specify developmental states. The atlas uncovers regulators of embryogenesis, including an unexpected role of a skin specifier in neurogenesis and the critical function of an uncharacterized TF in convergent muscle differentiation. At the systems level, the atlas provides an opportunity to model cell state-fate relationships, revealing a lineage-dependent state diversity within functionally related cells and a winding trajectory of developmental state progression. Collectively, this single-cell protein atlas represents a valuable resource for elucidating metazoan embryogenesis at the molecular and systems levels.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Desenvolvimento Embrionário , Regulação da Expressão Gênica no Desenvolvimento , Análise de Célula Única/métodos , Análise Espaço-Temporal , Fatores de Transcrição/metabolismo , Animais , Caenorhabditis elegans/embriologia , Diferenciação Celular , Linhagem da Célula
10.
J Virol ; 97(10): e0078623, 2023 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-37796126

RESUMO

IMPORTANCE: EV71 poses a significant health threat to children aged 5 and below. The process of EV71 infection and replication is predominantly influenced by ubiquitination modifications. Our previous findings indicate that EV71 prompts the activation of host deubiquitinating enzymes, thereby impeding the host interferon signaling pathway as a means of evading the immune response. Nevertheless, the precise mechanisms by which the host employs ubiquitination modifications to hinder EV71 infection remain unclear. The present study demonstrated that the nonstructural protein 2Apro, which is encoded by EV71, exhibits ubiquitination and degradation mediated by the host E3 ubiquitin ligase SPOP. In addition, it is the first report, to our knowledge, that SPOP is involved in the host antiviral response.


Assuntos
Cisteína Endopeptidases , Enterovirus Humano A , Infecções por Enterovirus , Interações entre Hospedeiro e Microrganismos , Ubiquitina-Proteína Ligases , Ubiquitina , Ubiquitinação , Proteínas Virais , Criança , Humanos , Enterovirus Humano A/enzimologia , Enterovirus Humano A/fisiologia , Infecções por Enterovirus/metabolismo , Infecções por Enterovirus/virologia , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Proteínas Virais/antagonistas & inibidores , Proteínas Virais/metabolismo , Cisteína Endopeptidases/metabolismo
11.
Diabetes Obes Metab ; 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38952343

RESUMO

AIM: Choosing the initial treatment for type 2 diabetes (T2D) is pivotal, requiring consideration of solid clinical evidence and patient characteristics. Despite metformin's historical preference, its efficacy in preventing cerebrovascular events lacked empirical validation. This study aimed to evaluate the associations between first-line monotherapy (metformin or non-metformin antidiabetic medications) and cerebrovascular complications in patients with T2D without diabetic complications. METHODS: We analysed 9090 patients with T2D without complications who were prescribed either metformin or non-metformin medications as initial therapy. Propensity score matching ensured group comparability. Cox regression analyses, stratified by initial metformin use, assessed cerebrovascular disease risk, adjusting for multiple covariates and using competing risk analysis. Metformin exposure was measured using cumulative defined daily doses. RESULTS: Metformin users had a significantly lower crude incidence of cerebrovascular diseases compared with non-users (p < .0001). Adjusted hazard ratios (aHRs) consistently showed an association between metformin use and a lower risk of overall cerebrovascular diseases (aHRs: 0.67-0.69) and severe events (aHRs: 0.67-0.69). The association with reduced risk of mild cerebrovascular diseases was significant across all models (aHRs: 0.73-0.74). Higher cumulative defined daily doses of metformin correlated with reduced cerebrovascular risk (incidence rate ratio: 0.62-0.94, p < .0001), indicating a dose-dependent effect. CONCLUSION: Metformin monotherapy is associated with a reduced risk of cerebrovascular diseases in early-stage T2D, highlighting its dose-dependent efficacy. However, the observed benefits might also be influenced by baseline differences and the increased risks associated with other medications, such as sulphonylureas. These findings emphasize the need for personalized diabetes management, particularly in mitigating cerebrovascular risk in early T2D stages.

12.
Soft Matter ; 20(21): 4257-4269, 2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38757213

RESUMO

Recent experimental studies have revealed a lack of universality in the extensional behavior of linear polymers, which is not envisioned by classical molecular theories. These surprising findings, particularly the sharp contrast between polymer melts and solutions, have catalyzed the development of new theoretical ideas, including the concept of friction reduction in highly stretched polymer melts. By presenting evidence from rheology and small-angle neutron scattering, this work shows that deformation-induced demixing, which is due to the viscoelastic asymmetry in binary mixtures, contributes to the observed nonuniversality. In the case of polystyrene/oligostyrene blends, demixing increases the effective glass transition temperature of the long chain, leading to an apparent friction enhancement. On the other hand, the opposite case is found for the polystyrene/poly(α-methylstyrene) blend. These results highlight the important influence of deformation-induced concentration fluctuations on polymer segmental friction.

13.
Org Biomol Chem ; 22(21): 4249-4253, 2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38717449

RESUMO

A Cu2O-catalyzed cascade phosphinylation/cyclization reaction of 2'-aminochalcones and diphenylphosphine oxides to produce hemi-indigo derivatives has been developed. This strategy facilitates the sequential formation of a C-P bonds and a C-N bond in a single reaction step. Notably, the approach features one-pot operation, an earth-abundant copper catalyst, readily available starting materials, a broad substrate scope and high compatibility with functional groups, providing 33 compounds in acceptable yields.

14.
Int J Hyperthermia ; 41(1): 2365388, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38880505

RESUMO

OBJECTIVES: To investigate the long-term efficacy of ultrasound-guided high-intensity focused ultrasound (USgHIFU) for multiple uterine fibroids and the factors associated with recurrence. MATERIALS AND METHODS: Five hundred and forty-nine patients with multiple uterine fibroids treated with USgHIFU from June 2017 to June 2019 were retrospectively analyzed. The Pictorial Blood Loss Assessment Chart (PBAC) was used to assess menstrual blood loss. The patients were asked to undergo pre- and post-USgHIFU magnetic resonance imaging (MRI) and complete routine follow-up after USgHIFU. Cox regression analysis was used to investigate the risk factors associated with recurrence. RESULTS: The median number of fibroids per patient was 3 (interquartile range: 3-4), and a total of 1371 fibroids were treated. Among them, 446 patients completed 3 years follow-up. Recurrence, defined as PBAC score above or equal to 100 and/or the residual fibroid volume increased by 10%, was detected in 90 patients within 3 years after USgHIFU, with a cumulative recurrence rate of 20.2% (90/446). The multi-factor Cox analysis showed that age was a protective factor for recurrence. Younger patients have a greater chance of recurrence than older patients. Mixed hyperintensity of fibroids on T2WI and treatment intensity were risk factors for recurrence. Patients with hyperintense uterine fibroids and treated with lower treatment intensity were more likely to experience recurrence than other patients after USgHIFU. No major adverse effects occurred. CONCLUSIONS: USgHIFU can be used to treat multiple uterine fibroids safely and effectively. The age, T2WI signal intensity and treatment intensity are factors related to recurrence.


Assuntos
Ablação por Ultrassom Focalizado de Alta Intensidade , Leiomioma , Humanos , Feminino , Leiomioma/terapia , Leiomioma/diagnóstico por imagem , Adulto , Fatores de Risco , Ablação por Ultrassom Focalizado de Alta Intensidade/métodos , Pessoa de Meia-Idade , Estudos Retrospectivos , Neoplasias Uterinas/terapia , Neoplasias Uterinas/diagnóstico por imagem , Resultado do Tratamento
15.
J Chem Phys ; 160(9)2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38445839

RESUMO

A method for characterizing the topological fluctuations in liquids is proposed. This approach exploits the concept of the weighted gyration tensor of a collection of particles and permits the definition of a local configurational unit (LCU). The first principal axis of the gyration tensor serves as the director of the LCU, which can be tracked and analyzed by molecular dynamics simulations. Analysis of moderately supercooled Kob-Andersen mixtures suggests that orientational relaxation of the LCU closely follows viscoelastic relaxation and exhibits a two-stage behavior. The slow relaxing component of the LCU corresponds to the structural, Maxwellian mechanical relaxation. Additionally, it is found that the mean curvature of the LCUs is approximately zero at the Maxwell relaxation time with the Gaussian curvature being negative. This observation implies that structural relaxation occurs when the configurationally stable and destabilized regions interpenetrate each other in a bicontinuous manner. Finally, the mean and Gaussian curvatures of the LCUs can serve as reduced variables for the shear stress correlation, providing a compelling proof of the close connection between viscoelastic relaxation and topological fluctuations in glass-forming liquids.

16.
J Sep Sci ; 47(1): e2300786, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38234027

RESUMO

Epimedium (EM) and Psoraleae Fructus (PF) are a traditional herb combination often used as a fixed form to treat osteoporosis disease in the clinic. However, the intricate interactions of this pair remain unknown. In our study, we undertook a comprehensive examination of their compatibility behaviors. Concurrently, a precise and sensitive quantitation method was successfully developed and validated using liquid chromatography-tandem mass spectrometry for the determination of 12 components. This method was applied in analyzing herbal extracts and biological samples (both in the portal vein and systemic plasma), which was also used to study the pharmacokinetics of the herb pair. The results indicated that the combination of EM and PF enhanced the dissolution of chemical components from PF in extracts, but it had a negligible influence on the contents of the components from EM. On the contrary, the in vivo exposure of the lowly exposed EM flavonoids significantly increased following the combination of EM and PF, whereas the highly exposed psoralen and isopsoralen were greatly reduced. These interactions might be crucial for the synergy and toxicity reduction of the herbal pair in disease treatment, which pave the way for further exploration into the clinical application and pharmacological mechanisms of EM and PF.


Assuntos
Medicamentos de Ervas Chinesas , Epimedium , Ratos , Animais , Medicamentos de Ervas Chinesas/análise , Espectrometria de Massas em Tandem/métodos , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida , Administração Oral
17.
Chaos ; 34(5)2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38717416

RESUMO

Mixed-mode oscillations (MMOs) are complex oscillatory behaviors of multiple-timescale dynamical systems in which there is an alternation of large-amplitude and small-amplitude oscillations. It is well known that MMOs in two-timescale systems can arise either from a canard mechanism associated with folded node singularities or a delayed Andronov-Hopf bifurcation (DHB) of the fast subsystem. While MMOs in two-timescale systems have been extensively studied, less is known regarding MMOs emerging in three-timescale systems. In this work, we examine the mechanisms of MMOs in coupled Morris-Lecar neurons with three distinct timescales. We investigate two kinds of MMOs occurring in the presence of a singularity known as canard-delayed-Hopf (CDH) and in cases where CDH is absent. In both cases, we examine how features and mechanisms of MMOs vary with respect to variations in timescales. Our analysis reveals that MMOs supported by CDH demonstrate significantly stronger robustness than those in its absence. Moreover, we show that the mere presence of CDH does not guarantee the occurrence of MMOs. This work yields important insights into conditions under which the two separate mechanisms in two-timescale context, canard and DHB, can interact in a three-timescale setting and produce more robust MMOs, particularly against timescale variations.

18.
Am J Otolaryngol ; 45(3): 104229, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38422555

RESUMO

PURPOSE: This multicenter, prospective study is designed to investigate whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is present in the Middle Ear Effusion (MEE) of patients developing Otitis Media with Effusion (OME) subsequent to an Omicron infection. The objective is to elucidate any potential association between the virus and the condition. METHODS: This study, conducted from January to June 2023, spanned the Otolaryngology departments of two medical institutions in Eastern China. Patients manifesting OME subsequent to Omicron infection from both hospitals were subjected to comprehensive otolaryngological assessments, including pure-tone audiometry (PTA), tympanometry, otoscopic examination, and nasopharyngolaryngoscopy. Subsequently, MEE samples extracted from these patients were analyzed through RT-PCR to detect SARS-CoV-2. RESULTS: In this study, 23 patients (32-84 years; 57.5 ± 14.8 mean age; 47.8 % male) presented OME in 25 ears post-Omicron infection, with 21 (91.3 %) exhibiting unilateral symptoms. The median duration from infection to MEE sampling was 21 days (IQR: 25-46; range: 11-150). Predominantly, 64.0 % exhibited Type B tympanograms, and fluid accumulation was observed in 88.0 % of ears. SARS-CoV-2 was detected in 3 MEE samples (12.0 %), with cycle threshold values ranging between 25.65 and 33.30. CONCLUSIONS: Our study highlights the potential effects of COVID-19 on the middle ear, suggesting a link between SARS-CoV-2 and OME onset. The virus, a significant contributor to OME, is detectable in the MEE nearly a month post-Omicron infection, indicating a potential alteration in OME treatment strategies and a risk of recurrence, emphasizing the necessity for otolaryngologist vigilance.


Assuntos
COVID-19 , Otite Média com Derrame , SARS-CoV-2 , Humanos , COVID-19/complicações , COVID-19/diagnóstico , Otite Média com Derrame/virologia , Otite Média com Derrame/diagnóstico , Masculino , Feminino , Pessoa de Meia-Idade , Estudos Prospectivos , Adulto , Idoso , Idoso de 80 Anos ou mais , China/epidemiologia , Testes de Impedância Acústica/métodos
19.
Heart Surg Forum ; 27(1): E058-E067, 2024 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-38286641

RESUMO

BACKGROUND: Low voltage areas (LVAs) on left atrial (LA) voltage mapping correlate with atrial fibrosis. However, there is no uniform standard for the definition of LVAs, or mapping techniques and mapping rhythms, so that the predictive value of left atrial LVAs for recurrence of atrial fibrillation (AF) is uncertain. This study aimed to explore the relationship between the presence of pre-ablation left atrial LVAs and the risk of recurrent AF after catheter ablation. METHODS: The databases of PubMed, Embase, Web of science, Cochrane library, Scopus, Wanfang Datebase, China National Knowledge Infrastructure, China Biology Medicine and China Scientific Journal Datebase were searched from inception to 31 July 2023. Relevant studies regarding left atrial LVAs prior to ablation to predict postoperative recurrence of AF were identified and analyzed. The efficacy endpoints were defined as the recurrence of atrial arrhythmia lasting over 30 s. RESULTS: A total of 12 studies with 1070 patients were included. We found the presence of pre-ablation left atrial LVAs correlated with the risk of recurrent AF after ablation (hazard ratio (HR) = 2.87, 95% confidence interval (CI): 2.33-3.52). The presence of pre-ablation left atrial LVAs can predict the risk of recurrent AF after ablation both in the follow-up duration ≤12 months group and follow-up duration >12 months group (follow-up duration ≤12 months: HR = 2.93, 95% CI: 2.20-3.90; follow-up duration >12 months: HR = 2.80, 95% CI: 2.09-3.77). The presence of pre-ablation left atrial LVAs correlated with the risk of recurrent AF after ablation in paroxysmal AF (HR = 2.89, 95% CI: 1.97-4.24). CONCLUSIONS: The presence of pre-ablation left atrial LVAs correlate with the risk of recurrent AF after catheter ablation.


Assuntos
Apêndice Atrial , Fibrilação Atrial , Ablação por Cateter , Humanos , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/cirurgia , Átrios do Coração/cirurgia , Apêndice Atrial/cirurgia , Fibrose , Ablação por Cateter/efeitos adversos , Ablação por Cateter/métodos , Recidiva , Resultado do Tratamento
20.
J Clin Nurs ; 33(5): 1777-1785, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38426618

RESUMO

BACKGROUND: Post-operative diarrhoea is a common adverse event after pancreatic surgery. While the risk factors for this condition have been identified, the increasing trend of administering chemotherapy before surgery might change these factors. This study aimed to identify the risk factors of post-operative diarrhoea in patients with pancreatic ductal adenocarcinoma (PDAC) who underwent neoadjuvant chemotherapy. DESIGN: A retrospective cohort study. METHODS: Patients who underwent neoadjuvant chemotherapy and pancreatectomy because of PDAC between 2021 and 2023 were included. The preoperative characteristics of, operative details of and post-operative outcomes in patients with and without post-operative diarrhoea were collected and compared. The independent risk factors of post-operative diarrhoea were identified using logistic regression analysis. STROBE checklist was used. RESULTS: Post-operative diarrhoea occurred in 65 out of 145 (44.8%) patients during hospitalization. Elevated white blood cell count, advanced tumour stage, and late abdominal drain removal were independent risk factors for post-operative diarrhoea (p < .001, p = .006 and p = .009, respectively). CONCLUSIONS: Some perioperative factors influence post-operative diarrhoea in patients who undergo neoadjuvant chemotherapy. More attention should be paid to patients at a higher risk of post-operative diarrhoea, with an emphasis on high-quality management for these patients.


Assuntos
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Humanos , Terapia Neoadjuvante/efeitos adversos , Estudos Retrospectivos , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/cirurgia , Neoplasias Pancreáticas/etiologia , Carcinoma Ductal Pancreático/patologia , Carcinoma Ductal Pancreático/cirurgia , Fatores de Risco , Diarreia/epidemiologia , Diarreia/etiologia
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