Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 106
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Basic Res Cardiol ; 119(1): 57-74, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38151579

RESUMO

Cardiac sympathetic overactivation is a critical driver in the progression of acute myocardial infarction (AMI). The left middle cervical ganglion (LMCG) is an important extracardiac sympathetic ganglion. However, the regulatory effects of LMCG on AMI have not yet been fully documented. In the present study, we detected that the LMCG was innervated by abundant sympathetic components and exerted an excitatory effect on the cardiac sympathetic nervous system in response to stimulation. In canine models of AMI, targeted ablation of LMCG reduced the sympathetic indexes of heart rate variability and serum norepinephrine, resulting in suppressed cardiac sympathetic activity. Moreover, LMCG ablation could improve ventricular electrophysiological stability, evidenced by the prolonged ventricular effective refractory period, elevated action potential duration, increased ventricular fibrillation threshold, and enhanced connexin43 expression, consequently showing antiarrhythmic effects. Additionally, compared with the control group, myocardial infarction size, circulating cardiac troponin I, and myocardial apoptosis were significantly reduced, accompanied by preserved cardiac function in canines subjected to LMCG ablation. Finally, we performed the left stellate ganglion (LSG) ablation and compared its effects with LMCG destruction. The results indicated that LMCG ablation prevented ventricular electrophysiological instability, cardiac sympathetic activation, and AMI-induced ventricular arrhythmias with similar efficiency as LSG denervation. In conclusion, this study demonstrated that LMCG ablation suppressed cardiac sympathetic activity, stabilized ventricular electrophysiological properties and mitigated cardiomyocyte death, resultantly preventing ischemia-induced ventricular arrhythmias, myocardial injury, and cardiac dysfunction. Neuromodulation therapy targeting LMCG represented a promising strategy for the treatment of AMI.


Assuntos
Infarto do Miocárdio , Animais , Cães , Arritmias Cardíacas , Coração/inervação , Fibrilação Ventricular/etiologia , Fibrilação Ventricular/prevenção & controle , Gânglios Simpáticos/metabolismo
2.
Clin Exp Pharmacol Physiol ; 51(6): e13863, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38650114

RESUMO

Chronic hyperglycaemia is a chief feature of diabetes mellitus and complicates with many systematic anomalies. Non-human primates (NHPs) are excellent for studying hyperglycaemia or diabetes and associated comorbidities, but lack behavioural observation. In the study, behavioural, brain imaging and histological analysis were performed in a case of spontaneously hyperglycaemic (HGM) Macaca fascicularis. The results were shown that the HGM monkey had persistent body weight loss, long-term hyperglycaemia, insulin resistance, dyslipidemia, but normal concentrations of insulin, C-peptide, insulin autoantibody, islet cell antibody and glutamic acid decarboxylase antibody. Importantly, an impaired working memory in a delayed response task and neurological dysfunctions were found in the HGM monkey. The tendency for atrophy in hippocampus was observed by magnetic resonance imaging. Lenticular opacification, lens fibres disruptions and vacuole formation also occurred to the HGM monkey. The data suggested that the spontaneous HGM monkey might present diabetes-like characteristics and associated neurobehavioral anomalies in this case. This study first reported cognitive deficits in a spontaneous hyperglycaemia NHPs, which might provide evidence to use macaque as a promising model for translational research in diabetes and neurological complications.


Assuntos
Catarata , Hiperglicemia , Macaca fascicularis , Animais , Hiperglicemia/metabolismo , Catarata/patologia , Masculino , Transtornos Cognitivos/etiologia , Transtornos Cognitivos/patologia , Doenças do Sistema Nervoso , Hipocampo/patologia , Hipocampo/metabolismo
3.
J Med Virol ; 95(11): e29215, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37933907

RESUMO

Respiratory tract infections are associated with the most common diseases transmitted among people and remain a huge threat to global public health. Rapid and sensitive diagnosis of causative agents is critical for timely treatment and disease control. Here, we developed a novel method based on recombinase polymerase amplification (RPA) combined with CRISPR-Cas12a to detect three viral pathogens, including SARS-CoV-2, influenza A, and influenza B, which cause similar symptom complexes of flu cold in the respiratory tract. The detection method can be completed within 1 h, which is faster than other standard detection methods, and the limit of detection is approximately 102 copies/µL. Additionally, this detection system is highly specific and there is no cross-reactivity with other common respiratory tract pathogens. Based on this assay, we further developed a more simplified RPA/CRISPR-Cas12a system combined with lateral flow assay on a manual microfluidic chip, which can simultaneously detect these three viruses. This low-cost detection system is rapid and sensitive, which could be applied in the field and resource-limited areas without bulky and expensive instruments, providing powerful tools for the point-of-care diagnostic.


Assuntos
COVID-19 , Influenza Humana , Orthomyxoviridae , Humanos , Recombinases , SARS-CoV-2 , Sistemas CRISPR-Cas , Nucleotidiltransferases , Técnicas de Amplificação de Ácido Nucleico
4.
Opt Lett ; 48(19): 5117-5120, 2023 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-37773399

RESUMO

In this paper, we propose a reflective terahertz (THz) Bessel metalens that utilizes polarization-insensitive sub-wavelength metal resonator-dielectric-metal structures. The Bessel metalens is configured with the superposition of hyperboloidal and conical phase profiles, resulting in a high-efficiency and long non-diffractive length Bessel beam. Our experimental results demonstrate that the proposed Bessel metalens has a focusing efficiency of 72.1% and a non-diffractive length of 239λ. This device has promising aspects in the fields of THz imaging systems and other miniaturized and integrated scenes that require non-diffractive Bessel beams.

5.
Nanotechnology ; 35(6)2023 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-37991485

RESUMO

Developing non-noble-metal electrocatalysts for hydrogen evolution reactions with high activity and stability is the key issue in green hydrogen generation based on electrolytic water splitting. It has been recognized that the stacking of large CoP particles limits the intrinsic activity of as-synthesized CoP catalyst for hydrogen evolution reaction. In the present study, N-MoxC/CoP-0.5 with excellent electrocatalytic activity for hydrogen evolution reaction was prepared using N-MoxC as decoration. A reasonable overpotential of 106 mV (at 10 mA cm-2) and a Tafel slope of 59 mV dec-1in 1.0 M KOH solution was achieved with N-MoxC/CoP-0.5 electrocatalyst, which exhibits superior activity even after working for 37 h. Uniformly distributed ultrafine nanoclusters of the N-MoxC/CoP-0.5 hybrids could provide sufficient interfaces for enhanced charge transfer. The effective capacity of the hydrogen evolution reaction could be preserved in the complex, and the enlarged electrocatalytic surface area could be expected to offer more active sites for the reaction.

6.
J Appl Microbiol ; 134(9)2023 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-37634085

RESUMO

AIMS: This study aimed to screen a bacterial strain with high detoxifying capability for aflatoxin B1 (AFB1), verify its biotransformation efficiency, and detoxification process. METHODS AND RESULTS: A total of 350 samples collected from different environmental niche were screened using coumarin as the sole carbon source. High Performance Liquid Chromatography (HPLC) was used to detect residues of AFB1, and 16S rRNA sequencing was performed on the isolated strain with the highest AFB1 removal ratio for identification. The detoxified products of this strain were tested for toxicity in Escherichia coli as well as LO2, Caco-2, and HaCaT human cell lines. HPLC-MS was applied to further confirm the AFB1 removal and detoxification process. CONCLUSIONS: We identified a strain from plant leaf designated as DT with high AFB1-detoxifying ability that is highly homologous to Bacillus aryabhattai. The optimum detoxification conditions of this strain were 37°C and pH 8.0, resulting in 82.92% removal ratio of 2 µg mL-1 AFB1 in 72 h. The detoxified products were nontoxic for E. coli and significantly less toxic for the LO2, Caco-2, and HaCaT human cell lines. HPLC-MS analysis also confirmed the significant drop of the AFB1 characteristic peak. Two possible metabolic products, C19H15O8 (m/z 371) and C19H19O8 (m/z 375), were observed by mass spectrometry. Potential biotransformation pathway was based on the cleavage of double bond in the terminal furan of AFB1. These generated components had different chemical structures with AFB1, manifesting that the attenuation of AFB1 toxicity would be attributed to the destruction of lactone structure of AFB1 during the conversion process.


Assuntos
Aflatoxina B1 , Escherichia coli , Humanos , Aflatoxina B1/metabolismo , Células CACO-2 , Escherichia coli/genética , Escherichia coli/metabolismo , RNA Ribossômico 16S/genética
7.
Cancer Cell Int ; 22(1): 50, 2022 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-35101032

RESUMO

BACKGROUND: Gastric cancer (GC) has a poor prognosis and limited therapeutic options. As a new promising cancer therapeutic approach, chimeric antigen receptor (CAR)-T cells represent a potential GC treatment. We investigated the antitumor activity of CAR-T cells target-B7H3 in GC. METHODS: In our study, expression of B7H3 was examined in GC tissues and explored the tumoricidal potential of B7H3-targeting CAR-T cells in GC. B7H3-directed CAR-T cells with a humanized antigen-recognizing domain was generated. The anti-tumor effects of this CAR-T cell were finally investigated in vitro and in vivo. RESULTS: Our results show that B7H3-directed CAR-T cells efficiently killed GC tumor cells. In addition, we found that B7H3 is correlated with tumor cell stemness, and anti-B7H3 CAR-T can simultaneously target stem cell-like GC cells to improve the treatment outcome. CONCLUSIONS: Our study indicates that B7H3 is an attractive target for GC therapy, and B7H3 has high potential for clinical application.

8.
J Fluoresc ; 32(2): 629-636, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35025017

RESUMO

The aim of this study was to establish a time-resolved fluorescent immunoassay (TRFIA) for the detection of serum Galectin-3 (Gal-3) and apply this method to evaluate the clinical significance of serum Gal-3 in predicting Idiopathic Membranous Nephropathy (IMN) progression. The Gal-3-TRFIA was established using the double antibody sandwich method, with the capture antibodies coated on a 96-well microplate and the detection antibodies chelated with Europium (III) (Eu3+). Serum Gal-3 was detected in 81 patients with IMN and 123 healthy controls to further evaluate the value of the Gal-3 in staging of IMN. The sensitivity of the Gal-3-TRFIA assay was 0.85 ng/mL, and the detection range was 0.85-1000 ng/mL. The Gal-3 intra-batch and inter-batch coefficients of variation were 3.45% and 5.12%, respectively. The correlation coefficient (R) between the Gal-3-TRFIA assay and commercially available enzyme-linked immunosorbent assay kits was 0.83. The serum Gal-3 concentration was higher in patients with IMN (65.57 ± 55.90 ng/mL) compared to healthy controls (16.29 ± 9.91 ng/mL, P < 0.0001). In this study, a wide detection range Gal-3-TRFIA assay was developed using lanthanide (Eu3+) chelates for the detection of Gal-3 concentrations in serum. Gal-3 concentration is elevated in patients with IMN.


Assuntos
Fluorimunoensaio/métodos , Galectina 3/sangue , Glomerulonefrite Membranosa/sangue , Glomerulonefrite Membranosa/diagnóstico , Anticorpos/sangue , Progressão da Doença , Ensaio de Imunoadsorção Enzimática , Galectina 3/imunologia , Humanos , Estudos Prospectivos , Sensibilidade e Especificidade , Fatores de Tempo
9.
Anal Bioanal Chem ; 413(6): 1665-1673, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33501552

RESUMO

Acquisition of the direct electrochemical response of protein is the cornerstone for the development of the third generation of electrochemical biosensors. In this work, we developed a nanocluster-assisted protein-film voltammetry technique (NCA-PFV) which can achieve the acquisition of the electrochemical signal and maintain the activity without affecting of the protein's structure. With this strategy, a lipid bilayer membrane is used to immobilize the membrane protein so as to maintain its natural state. Copper nanoclusters with a size smaller than most proteins are then used to function at sub-protein scale and to mediate the electron hopping from the electroactive center of the electrode. As a model, the direct electrochemical signal of cyclooxygenase (COX) is successfully obtained, with a pair of well-defined redox peaks located at -0.39 mV and -0.31 mV, which characterize the heme center of the enzyme. Its catalytic activity towards the substrate arachidonic acid (AA) is also retained. The detection range for AA is 10-1000 µM and the detection limit is 2.4 µM. Electrochemical monitoring of the regulation of the catalytic activity by an inhibitor DuP-697 is also achieved. This work provides a powerful tool for the fabrication of enzyme-based electrochemical biosensors, and is also of great significance for promoting the development and application of next-generation electrochemical biosensors.


Assuntos
Técnicas Biossensoriais/métodos , Cobre/química , Eletroquímica/métodos , Heme/análise , Nanopartículas/análise , Prostaglandina-Endoperóxido Sintases/química , Ácido Araquidônico/química , Carbono/química , Catálise , Eletrodos , Heme/química , Humanos , Bicamadas Lipídicas/química , Microscopia Eletrônica de Transmissão , Nanopartículas/química , Oxirredução
10.
Int J Clin Pract ; 75(3): e13632, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32745308

RESUMO

BACKGROUND: The profiles of liver function abnormalities in COVID-19 patients need to be clarified. METHODS: In this retrospective study, consecutive COVID-19 patients over 60 years old in Renmin Hospital of Wuhan University from January 1 to February 6 were included. Data of demographics, clinical characteristics, comorbidities, laboratory tests, medications and outcomes were collected and analysed. Sequential alterations of serum alanine aminotransferase (ALT) were monitored. RESULTS: A total of 330 patients were included and classified into two groups with normal (n = 234) or elevated ALT (n = 96). There were fewer females (40.6% vs 54.7%, P = .020) and more critical cases (30.2% vs 19.2%, P = .026) in patients with elevated ALT compared with the normal group. Higher levels of bacterial infection indices (eg, white blood cell count, neutrophil count, C-reactive protein and procalcitonin) were observed in the elevated group. Spearman correlation showed that both ALT and AST levels were positively correlated with those indices of bacterial infection. No obvious effects of medications on ALT abnormalities were found. In patients with elevated ALT, most ALT elevations were mild and transient. 59.4% of the patients had ALT concentrations of 41-100 U/L, while only a few patients (5.2%) had high serum ALT concentrations above 300 U/L. ALT elevations occurred at 13 (10-17) days and recovered at 28 (18-35) days from disease onset. For most patients, the elevation of serum ALT levels occurred at 6-20 days after disease onset and reached their peak values within a similar time frame. The recovery of serum ALT levels to normal frequently occurred at 16-20 days or 31-35 days after disease onset. CONCLUSIONS: Liver function abnormalities were observed in 29.1% of elderly people COVID-19 patients, which were slightly and transient in most cases. Liver function abnormalities in COVID-19 may be correlated with bacterial infection.


Assuntos
COVID-19 , Hepatopatias , Idoso , Feminino , Humanos , Fígado , Testes de Função Hepática , Pessoa de Meia-Idade , Estudos Retrospectivos , SARS-CoV-2
11.
Sensors (Basel) ; 21(4)2021 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-33562752

RESUMO

In this paper, a polyimide (PI)/Si/SiO2-based piezoresistive microcantilever biosensor was developed to achieve a trace level detection for aflatoxin B1. To take advantage of both the high piezoresistance coefficient of single-crystal silicon and the small spring constant of PI, the flexible piezoresistive microcantilever was designed using the buried oxide (BOX) layer of a silicon-on-insulator (SOI) wafer as a bottom passivation layer, the topmost single-crystal silicon layer as a piezoresistor layer, and a thin PI film as a top passivation layer. To obtain higher sensitivity and output voltage stability, four identical piezoresistors, two of which were located in the substrate and two integrated in the microcantilevers, were composed of a quarter-bridge configuration wheatstone bridge. The fabricated PI/Si/SiO2 microcantilever showed good mechanical properties with a spring constant of 21.31 nN/µm and a deflection sensitivity of 3.54 × 10-7 nm-1. The microcantilever biosensor also showed a stable voltage output in the Phosphate Buffered Saline (PBS) buffer with a fluctuation less than 1 µV @ 3 V. By functionalizing anti-aflatoxin B1 on the sensing piezoresistive microcantilever with a biotin avidin system (BAS), a linear aflatoxin B1 detection concentration resulting from 1 ng/mL to 100 ng/mL was obtained, and the toxic molecule detection also showed good specificity. The experimental results indicate that the PI/Si/SiO2 flexible piezoresistive microcantilever biosensor has excellent abilities in trace-level and specific detections of aflatoxin B1 and other biomolecules.


Assuntos
Aflatoxina B1/análise , Técnicas Biossensoriais , Óxidos , Dióxido de Silício
12.
Zhongguo Zhong Yao Za Zhi ; 46(17): 4438-4445, 2021 Sep.
Artigo em Zh | MEDLINE | ID: mdl-34581048

RESUMO

The chemical constituents from the stems and leaves of Clausena excavata were isolated and purified by column chromatography with silica gel, ODS, Sephadex LH-20 and RP-HPLC. The chemical structures of the isolated compounds were identified on the basis of physicochemical properties, spectroscopic analysis, as well as the comparisons with the data reported in literature. Nineteen compounds were isolated from the 90% ethanol extract of the stems and leaves of C. excavata, which were identified as methyl orsellinate(1), syringaresinol(2), lenisin A(3), scopoletin(4), osthenol(5), N-benzoyltyrarnine methyl ether(6), N-p-coumaroyltyramine(7), aurantiamide acetate(8), 1H-indole-3-carboxaldehyde(9), furostifoline(10), clausenalansine E(11), 3-formylcarbazole(12), clausine L(13), clausine E(14), methyl carbazole-3-carboxylate(15), glycosinin(16), murrayafoline A(17), clausine H(18) and 2,7-dihydroxy-3-formyl-1-(3'-methyl-2'-butenyl)carbazole(19). Among these isolated compounds, compounds 1-11 were isolated from C. excavata for the first time, and compounds 1, 2 and 10 were isolated from the genus Clausena for the first time. In addition, this study evaluated the anti-rheumatoid arthritis activities of compounds 1-19 by measuring their anti-proliferative effects on synoviocytes in vitro according to MTS method. Compounds 10-19 displayed remarkable anti-rheumatoid arthritis activities, which exhibited the inhibitory effects on the proliferation of MH7 A synovial fibroblast cells with the IC_(50) values ranging from(27.63±0.18) to(235.67±2.16) µmol·L~(-1).


Assuntos
Clausena , Sinoviócitos , Proliferação de Células , Cromatografia de Fase Reversa , Folhas de Planta
13.
Opt Express ; 28(7): 10329-10336, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-32225620

RESUMO

We report a tunable terahertz (THz) metamaterial absorber (MA) actuated by thermomechanical bimaterial microcantilevers. The THz MA, which is suspended on a silicon substrate by the bimaterial microcantilevers, is a sandwich structure with a bottom Al ground plane, middle air and SiNx dielectric layers, and a top Al rotationally symmetric open split ring resonator. Upon application of a current, a Ti heating resistor integrated on the SiNx dielectric layer induces the bimaterial microcantilevers to bend, causing the air layer thickness to change, modulating the absorption of the THz MA. The tunable THz MA exhibited a relative modulation depth of absorption of 28.1% at 0.69 THz and a thermomechanical sensitivity of 0.12°/K. This tunable THz MA has potential applications in filtering, modulation, control, and THz imaging.

14.
Bioorg Chem ; 101: 104030, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32615467

RESUMO

Two new prenylated chromones, artoheterophines A (1) and B (2), five known prenylated chromones (3-7), as well as five known biogenetically related prenylated flavonoids (8-12) were isolated and characterized from the stems and leaves of A. heterophyllus. Their chemical structures were unambiguously determined through comprehensive spectral data analyses. The antiproliferative and anti-inflammatory effects of all these isolated prenylated chromones and flavonoids were evaluated in vitro. As a result, compounds 1-12 showed notable inhibitory effects against various human cancer cell lines with IC50 values ranging from 0.36 ± 0.02 to 22.09 ± 0.16 µM. Meanwhile, compounds 1-12 exhibited significant inhibitory activities on nitric oxide (NO) production holding IC50 values in the range of 0.48 ± 0.05-19.87 ± 0.21 µM. These research results suggest that the isolation and characterization of these prenylated chromones (1-7) and flavonoids (8-12) holding significant antiproliferative and anti-inflammatory activities could be significant to the discovery and development of new natural anti-tumor and anti-inflammatory drugs. The findings also provides a phytochemical evidence for further development and utilization of the stems and leaves of A. heterophyllus in health and pharmaceutical products.


Assuntos
Anti-Inflamatórios/uso terapêutico , Cromonas/química , Flavonoides/química , Anti-Inflamatórios/farmacologia , Proliferação de Células , Humanos , Estrutura Molecular , Relação Estrutura-Atividade
15.
Bioorg Chem ; 105: 104388, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33130343

RESUMO

A phytochemical investigation on the stems and leaves of Wikstroemia chuii resulted in the isolation of three new daphnane diterpenes, wikstroechuins A-C (1-3), together with eight known analogues (4-11). The structures of new daphnane diterpenes (1-3) were determined on the basis of extensive spectroscopic methods and the known daphnane diterpenes (4-11) were identified by comparing their observable spectroscopic data with those reported spectral data in the literature. The anti-inflammatory effects as well as anti-HIV activities in vitro of all isolated daphnane diterpenes 1-11 were assessed. As a consequence, daphnane diterpenes 1-11 displayed remarkable inhibitory activities on NO (nitric oxide) production induced by lipopolysaccharide in mouse macrophage RAW 264.7 cells showing IC50 values in the range of 0.12 ± 0.03 to 10.58 ± 0.16 µM. Meanwhile, daphnane diterpenes 1-11 displayed significant anti-HIV-1 reverse transcriptase (RT) effects showing EC50 values ranging from 0.09509 to 8.62356 µM. These research results indicated that the discovery of these new daphnane diterpenes with remarkable anti-inflammatory and anti-HIV activities from W. chuii, especially these new ones, could be extremely meaningful to the discovery of new anti-inflammatory agents and anti-HIV drugs as well as their potential practical values in the health and pharmaceutical products.


Assuntos
Fármacos Anti-HIV/farmacologia , Anti-Inflamatórios não Esteroides/farmacologia , Diterpenos/farmacologia , Inibidores da Transcriptase Reversa/farmacologia , Wikstroemia/química , Animais , Fármacos Anti-HIV/química , Fármacos Anti-HIV/isolamento & purificação , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/isolamento & purificação , Diterpenos/química , Diterpenos/isolamento & purificação , Relação Dose-Resposta a Droga , HIV/efeitos dos fármacos , Transcriptase Reversa do HIV/antagonistas & inibidores , Transcriptase Reversa do HIV/metabolismo , Lipopolissacarídeos/antagonistas & inibidores , Lipopolissacarídeos/farmacologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Camundongos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Óxido Nítrico/antagonistas & inibidores , Óxido Nítrico/biossíntese , Folhas de Planta/química , Células RAW 264.7 , Inibidores da Transcriptase Reversa/química , Inibidores da Transcriptase Reversa/isolamento & purificação , Relação Estrutura-Atividade
16.
J Cardiovasc Electrophysiol ; 30(3): 374-382, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30516302

RESUMO

INTRODUCTION: Our recent study found that selective ablation of the distal part of the ligament of Marshall (LOMLSPV ) could suppress ventricular arrhythmias (VAs) during acute myocardial infarction (AMI). This study was to investigate the possible underlying mechanisms. METHODS: Dogs were randomly divided into the sham-operated group (SO; n = 6), AMI group (AMI; n = 8) and the group undergoing LOMLSPV ablation ahead of AMI (LOMD+AMI; n = 8). Incidence of VAs, serum levels of malondialdehyde (MDA) and superoxide dismutase (SOD), expression of connexin (Cx43), Bcl-2, Bax, caspase-3, tumor necrosis factor (TNF)-α, interleukin-6 (IL-6), and high mobility group box (HMGB)1 were compared. Anatomic and immunostaining examinations of LOM LSPV were performed. RESULTS: Compared with the AMI group, incidence of VAs was reduced in the LOMD+AMI group. Compared with the SO group, Cx43, SOD, and Bcl-2 were decreased, MDA, Bax, caspase-3, TNF-α, IL-6, and HMGB1 were increased in the MI group, and all the alterations were significantly restrained in the LOMD+AMI group. A visual nerve fiber communication between the left stellate ganglion (LSG) and LOM and abundant sympathetic nerve bundles distribution in LOMLSPV were revealed. CONCLUSIONS: LOMLSPV ablation could suppress VAs during AMI. The possible mechanism may be associated with disconnection of the sympathetic conduit from LSG to the ventricles. Preservation of Cx43, inhibition of cardiac oxidative stress, apoptosis, and inflammation may be involved.


Assuntos
Arritmias Cardíacas/prevenção & controle , Ablação por Cateter , Ligamentos/cirurgia , Infarto do Miocárdio/cirurgia , Potenciais de Ação , Animais , Apoptose , Proteínas Reguladoras de Apoptose/metabolismo , Arritmias Cardíacas/metabolismo , Arritmias Cardíacas/patologia , Arritmias Cardíacas/fisiopatologia , Conexina 43/metabolismo , Modelos Animais de Doenças , Cães , Frequência Cardíaca , Mediadores da Inflamação/metabolismo , Ligamentos/inervação , Ligamentos/metabolismo , Ligamentos/patologia , Masculino , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/patologia , Infarto do Miocárdio/fisiopatologia , Miocárdio/metabolismo , Miocárdio/patologia , Estresse Oxidativo , Gânglio Estrelado/fisiopatologia
17.
Pacing Clin Electrophysiol ; 42(1): 13-19, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30426527

RESUMO

BACKGROUND: Atrial ganglionated plexus (GP) ablation was proved to have therapeutic effects on vasovagal syncope. The study aimed to investigate whether selective ablation of only right anterior GP (ARGP) and right inferior GP (IRGP) was effective in a canine model of vasovagal syncope. METHODS: Seventeen mongrel dogs were divided into control (N = 10) and ablation group (N = 7). Bilateral thoracotomy was performed at the fourth intercostal space and ARGP and IRGP were ablated in the ablation group. A bolus of veratridine (15 ug/kg) was injected into the left atrium to induce vasovagal reflex. Surface electrocardiogram and blood pressure (BP) were continuously monitored. Heart rate (HR) variability was calculated to represent cardiac autonomic tone. RESULTS: Veratridine injection induced vasovagal reflex in all dogs. HR decreased from 149 ± 17 to 89 ± 33 beats/min (P < 0.001) in the control group, while in the ablation group HR decreased from 141 ± 35 to 125 ± 34 beats/min (P = 0.032). The postveratridine HR in the ablation group was significantly higher than that in the control group (P = 0.045). A significantly less intense HR decrease was observed in the ablation group compared with control (-17 ± 16 vs -61 ± 34 beats/min, P = 0.006). Significant BP decreases were induced in both the groups (all P < 0.01), while no evident differences in postveratridine BP and the extent of BP decreases were found between the groups. HR variability revealed significant decrease in cardiac vagal tone after ablation [high-frequency power, 0.50 (0.17-1.05) vs 6.28 (0.68-8.99) ms2 , P = 0.005]. CONCLUSIONS: Selective ablation of ARGP + IRGP weakened cardiac parasympathetic control and significantly attenuated the cardioinhibitory response in an animal model of vasovagal reflex. This ablation strategy might be effective for vasovagal syncope with evident cardioinhibitory response.


Assuntos
Ablação por Cateter/métodos , Gânglios Autônomos/cirurgia , Átrios do Coração/cirurgia , Sistema de Condução Cardíaco/fisiopatologia , Síncope Vasovagal/cirurgia , Animais , Modelos Animais de Doenças , Cães , Eletrocardiografia , Gânglios Autônomos/fisiopatologia , Átrios do Coração/fisiopatologia , Síncope Vasovagal/fisiopatologia , Toracotomia , Veratridina
18.
Plant Cell Environ ; 41(1): 50-63, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28152567

RESUMO

High sensitivity of seeds to water loss is a widespread phenomenon in the world's plant species. The molecular basis of this trait is poorly understood but thought to be associated with critical changes in membrane function. We profiled membrane lipids of seeds in eight species with varying levels of desiccation tolerance and found a close association between reducing seed viability and increasing phosphatidic acid (PA). We applied hydration-dehydration cycles to Arabidopsis seeds, which are normally desiccation tolerant, to mimic the onset of desiccation sensitivity with progression towards germination and examined the role of phospholipase D (PLD) in desiccation stress-induced production of PA. We found that PLDα1 became more abundant and migrated from the cytosol to the membrane during desiccation, whereas PLDδ did not change, and that all desiccation-induced PA was derived from PLDα1 hydrolysis. When PLDα1 was suppressed, the germination level after each hydration-dehydration cycle improved significantly. We further demonstrated that PLDα1-mediated PA formation modulates desiccation sensitivity as applying its inhibitor improved seed desiccation tolerance and its suppression in protoplasts enhanced survival under dehydration. The insights provided by comparative lipidomics enable us to propose a new membrane-based model for seed desiccation stress and survival.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Arabidopsis/fisiologia , Dessecação , Ácidos Fosfatídicos/metabolismo , Fosfolipase D/metabolismo , Sementes/enzimologia , Sementes/fisiologia , Sobrevivência de Tecidos/fisiologia , Adaptação Fisiológica/efeitos dos fármacos , Arabidopsis/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Cotilédone/metabolismo , Citoplasma/efeitos dos fármacos , Citoplasma/metabolismo , Inibidores Enzimáticos/farmacologia , Germinação/efeitos dos fármacos , Lipídeos/análise , Transporte Proteico/efeitos dos fármacos , Protoplastos/efeitos dos fármacos , Protoplastos/metabolismo , Sementes/efeitos dos fármacos , Especificidade da Espécie , Frações Subcelulares/efeitos dos fármacos , Frações Subcelulares/metabolismo , Sobrevivência de Tecidos/efeitos dos fármacos
19.
J Cardiovasc Electrophysiol ; 29(9): 1299-1307, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29864240

RESUMO

INTRODUCTION: Cardiac sympathetic activation facilitates atrial electrical remodeling during atrial fibrillation (AF). Selective ablation of the distal part of the ligament of Marshall (LOMLSPV ) could decrease cardiac sympathetic innervation. This study aimed to investigate the effects of LOMLSPV ablation on atrial electrical remodeling in a short-term rapid atrial pacing (RAP) model. METHODS: In 16 anesthetized dogs, 6 hours of RAP (20 Hz, 2 × threshold) was delivered before LOMLSPV ablation (group 1, N  =  8) or after (group 2, N  =  8). Heart rate variability (HRV), serum norepinephrine (NE), atrial electrophysiological indices were analyzed. Six times of burst pacing (20 Hz, 2 × threshold, lasting for 5 seconds, were performed to induce AF, the number of episodes and the duration of AF were compared. RESULTS: LOMLSPV ablation decreased sympathetic indices of HRV and serum NE. Atrial effective refractory period (ERP) was shortened during RAP in both groups with higher reduction degrees in group 1. In group 1, the shortening of atrial ERP, elevating of ERP dispersion and sum of window of vulnerability (ΣWOV), facilitating of AF induced by RAP were subsequently reversed by LOMLSPV ablation. In group 2, LOMLSPV ablation prolonged atrial ERP, decreased ΣWOV, eliminated AF induction. The subsequent RAP failed to alter these indices. Histological studies showed abundant sympathetic nerve fibers in LOMLSPV . CONCLUSION: LOMLSPV ablation could inhibit atrial electrical remodeling during short-term RAP by reducing the cardiac sympathetic activity. LOMLSPV may be a potential target in AF ablation, especially in patients with highly cardiac sympathetic activation or atrial electrical remodeling.


Assuntos
Fibrilação Atrial/terapia , Remodelamento Atrial/fisiologia , Estimulação Cardíaca Artificial/métodos , Ablação por Cateter/métodos , Eletrocardiografia/métodos , Átrios do Coração , Animais , Fibrilação Atrial/fisiopatologia , Cães , Átrios do Coração/fisiopatologia , Átrios do Coração/cirurgia , Masculino , Distribuição Aleatória , Fatores de Tempo
20.
Opt Express ; 26(20): 26227-26234, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-30469713

RESUMO

In this paper, we demonstrate an ultra-broadband terahertz (THz) bi-metasurfaces absorber composed of two stacking metasurfaces backed by a metallic ground plane. The bottom metasurface consists of four multiplexed cross resonators with different geometries on a thin parylene layer, achieving a bandwidth of 3.80 THz with the absorption higher than 50% at high frequency. Meanwhile, the top metasurface, including two multiplexed cross resonators with different sizes on a relatively thicker parylene layer, provides a low frequency absorption band with an additional Salisbury screen absorption peak that connects the two absorption bands of the two metasurfaces, therefore enabling an ultra-broadband absorption. The experimental absorption spectrum of the bi-metasurfaces shows a bandwidth of 4.46 THz while the absorption exceeding 50% and a full width at half maxima (FWHM) of 97.7%. The ultra-broadband absorber will be a promising candidate for THz broadband detection.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA