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1.
J Phys Condens Matter ; 36(39)2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38906126

RESUMO

In this paper, we have systematically studied the electronic instability of pressured black phosphorous (BP) under strong magnetic field. We first present an effective model Hamiltonian for pressured BP near theLifshitzpoint. Then we show that when the magnetic field exceeds a critical value, the nodal-line semimetal (NLSM) state of BP with a small band overlap re-enters the semiconductive phase by re-opening a small gap. This results in a narrow-bandgap semiconductor with a partially flat valence band edge. Moreover, we demonstrate that above this critical magnetic field, two possible instabilities, i.e. charge density wave phase and excitonic insulator (EI) phase, are predicted as the ground state for high and low doping concentrations, respectively. By comparing our results with the experiment (Sunet al2018Sci. Bull.631539), we suggest that the field-induced instability observed experimentally corresponds to an EI. Furthermore, we propose that the semimetallic BP under pressure with small band overlaps may provide a good platform to study the magneto-exciton insulators. Our findings bring the first insight into the electronic instability of topological NLSM in the quantum limit.

2.
J Phys Condens Matter ; 36(25)2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38457834

RESUMO

A variety of distinct anisotropic exchange interactions commonly exist in one magnetic material due to complex crystal, magnetic and orbital symmetries. Here we investigate the effects of multiple anisotropic exchange interactions on topological magnon in a honeycomb ferromagnet, and find a chirality-selective topological magnon phase transition induced by a complicated interplay of Dzyaloshinsky-Moriya interaction and pseudo-dipolar interaction, accompanied by the bulk gap close and reopen with chiral inversion. Moreover, this novel topological phase transition involves band inversion at high symmetry pointsKandK', which can be regarded as a pseudo-orbital reversal, i.e. magnon valley degree of freedom, implying a new manipulation corresponding to a sign change of the magnon thermal Hall conductivity. Indeed, it can be realized in 4dor 5dcorrelated materials with both spin-orbit coupling and orbital localized states, such as iridates and ruthenates,etc.This novel regulation may have potential applications on magnon devices and topological magnonics.

3.
Phys Chem Chem Phys ; 26(12): 9687-9696, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38470341

RESUMO

Twisted bilayer graphene (tBLG) with C vacancies would greatly improve the density of states (DOS) around the Fermi level (EF) and quantum capacitance; however, the single-band tight-binding model only considering pz orbitals cannot accurately capture the low-energy physics of tBLG with C vacancies. In this work, a three-band tight-binding model containing three p orbitals of C atoms is proposed to explore the modulation mechanism of C vacancies on the DOS and quantum capacitance of tBLG. We first obtain the hopping integral parameters of the three-band tight-binding model, and then explore the electronic structures and the quantum capacitance of tBLG at a twisting angle of θ = 1.47° under different C vacancy concentrations. The impurity states contributed by C atoms with dangling bonds located around the EF and the interlayer hopping interaction could induce band splitting of the impurity states. Therefore, compared with the quantum capacitance of pristine tBLG (∼18.82 µF cm-2) at zero bias, the quantum capacitance is improved to ∼172.76 µF cm-2 at zero bias, and the working window with relatively large quantum capacitance in the low-voltage range is broadened in tBLG with C vacancies due to the enhanced DOS around the EF. Moreover, the quantum capacitance of tBLG is further increased at zero bias with an increase of the C vacancy concentration induced by more impurity states. These findings not only provide a suitable multi-band tight-binding model to describe tBLG with C vacancies but also offer theoretical insight for designing electrode candidates for low-power consumption devices with improved quantum capacitance.

4.
J Phys Condens Matter ; 36(12)2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-38061072

RESUMO

The Mn-Bi-Te family displaying magnetism and non-trivial topological properties has received extensive attention. Here, we predict that the antiferromagnetic structure of Mn3Bi2Te6with three MnTe layers is energetically stable and the magnetic energy difference of Mn-Mn is enhanced four times compared with that in the single MnTe layer of MnBi2Te4. The predicted Néel transition point is raised to 102.5 K, surpassing the temperature of liquid nitrogen. The topological properties show that with the variation of the MnTe layer from a single layer to three layers, the system transforms from a non-trivial topological phase to a trivial topological phase. Interestingly, the ferromagnetic state of Mn3Bi2Te6is a topological semimetal and it exhibits a topological transition from trivial to non-trivial induced by the magnetic transition. Our results enrich the Mn-Bi-Te family system, offer a new platform for studying topological phase transitions, and pave a new way to improve the working temperature of magnetically topological devices.

5.
J Phys Condens Matter ; 36(9)2023 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-37964592

RESUMO

Kagome lattice provides a distinctive platform to investigate various correlated electron orders. Recently, an unconventional charge density wave (CDW) with novel chirality is observed in the kagome metalAV3Sb5(A= K, Rb, Cs), and the origin of which is still unclear. Here, using a tight-binding model and the mean-field method, we calculate the electron order in the quasi-two-dimensional kagome lattice with 1/3 electron filling, and show that the chiral CDW emerges under a set of parameters withC6rotational symmetry but without mirror symmetry. Physically, the reason why we choose this set of parameters is based on the possible tangential distortion of the kagome lattice. Our results provide a fresh insight to understand the microscopic origin of the unconventional CDW inAV3Sb5.

6.
J Phys Condens Matter ; 34(49)2022 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-36223790

RESUMO

Topological magnons in a one-dimensional (1D) ferromagnetic Su-Schrieffer-Heeger (SSH) model with anisotropic exchange interactions are investigated. Apart from the intercellular isotropic Heisenberg interaction, the intercellular anisotropic exchange interactions, i.e. Dzyaloshinskii-Moriya interaction and pseudo-dipolar interaction, also can induce the emergence of the non-trivial phase with two degenerate in-gap edge states separately localized at the two ends of the 1D chain, while the intracellular interactions instead unfavors the topological phase. The interplay among them has synergistic effects on the topological phase transition, very different from that in the two-dimensional (2D) ferromagnet. These results demonstrate that the 1D magnons possess rich topological phase diagrams distinctly different from the electronic version of the SSH model and even the 2D magnons. Due to the low dimensional structural characteristics of this 1D topological magnonic system, the magnonic crystals can be constructed from bottom to top, which has important potential applications in the design of novel magnonic devices.

7.
Cell Mol Life Sci ; 79(3): 146, 2022 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-35190902

RESUMO

Calcific aortic valve disease (CAVD) is a common valve disease characterized by the fibro-calcific remodeling of the aortic valves, which is an actively regulated process involving osteogenic differentiation of valvular interstitial cells (VICs). MicroRNA (miRNA) is an essential regulator in diverse biological processes in cells. The present study aimed to explore the role and mechanism of miR-22 in the osteogenic differentiation of VICs. The expression profile of osteogenesis-related miRNAs was first detected in aortic valve tissue from CAVD patients (n = 33) and healthy controls (n = 12). miR-22 was highly expressed in calcified valve tissues (P < 0.01), and the expression was positively correlated with the expression of OPN (rs = 0.820, P < 0.01) and Runx2 (rs = 0.563, P < 0.01) in VICs isolated from mild or moderately calcified valves. The sustained high expression of miR-22 was also validated in an in-vitro VICs osteogenic model. Adenovirus-mediated gain-of-function and loss-of-function experiments were then performed. Overexpression of miR-22 significantly accelerated the calcification process of VICs, manifested by significant increases in calcium deposition, alkaline phosphate activity, and expression of osteoblastic differentiation markers. Conversely, inhibition of miR-22 significantly negated the calcification process. Subsequently, calcium-binding protein 39 (CAB39) was identified as a target of miR-22. Overexpression of miR-22 significantly reduced the expression of CAB39 in VICs, leading to decreased catalytic activity of the CAB39-LKB1-STRAD complex, which, in turn, exacerbated changes in the AMPK-mTOR signaling pathway, and ultimately accelerated the calcification process. In addition, ROS generation and autophagic activity during VIC calcification were also regulated by miR-22/CAB39 pathway. These results indicate that miR-22 is an important accelerator of the osteogenic differentiation of VICs, and a potential therapeutic target in CAVD.


Assuntos
Estenose da Valva Aórtica/patologia , Valva Aórtica/patologia , Calcinose/patologia , Proteínas de Ligação ao Cálcio/metabolismo , Diferenciação Celular , MicroRNAs/genética , Osteogênese , Idoso , Valva Aórtica/metabolismo , Estenose da Valva Aórtica/genética , Estenose da Valva Aórtica/metabolismo , Calcinose/genética , Calcinose/metabolismo , Proteínas de Ligação ao Cálcio/genética , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
8.
J Phys Condens Matter ; 33(41)2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34289462

RESUMO

The high-pressure (HP) properties of TlFeSe2are investigated based on the first-principles calculations combined with structure-searching method. The low-pressureC2/mphase will transform into the orthorhombicPnmaphase at 2 GPa, with 8% volume collapse, the insulator-metal transition and the bicollinear antiferromagnetic-to-nonmagnetic spin-crossover. At pressure higher than 8 GPa, the HPC2/mphase will become the ground state. BothPnmaphase and HPC2/mphase are constituted by one-dimensional chains of edge-sharing FeSe5tetragonal pyramids. Pressuring decrease the Se-Se bond length giving rise to the transition from [Se2]3-to [Se2]2-. Negative charge transfer causes the Fe2+with ∼2 µBmagnetic moment at ambient pressure and the nonmagnetic Fe1.5+at higher pressure. The Fermi surfaces of HP phases are also discussed.

9.
Phys Chem Chem Phys ; 23(16): 9679-9685, 2021 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-33624668

RESUMO

Spin-crossover combined with metal-insulator transition and superconductivity has been found in 2D transition-metal phosphorous trichalcogenides when tuning them by high pressure. Simulation of such intriguing spin-crossover behaviors is crucial to understanding the mechanism. The Hubbard U correction is widely used to describe the strong on-site Coulomb interaction in the d electrons of transition-metal compounds, while the U values are sensitive to the crystal field and spin state varying greatly with pressure. In this work, we show that taking MnPS3 as an example and based on a uniform parameter set, the hybrid functional calculations give a spin-crossover pressure of 35 GPa consistent with experimental observation (30 GPa), which is less than half of the existing reported value (63 GPa) using the Hubbard U correction. Notably, we find a spin-crossover induced transition from an antiferromagnetic semiconductor with monoclinic stacking-order to a ferromagnetic semiconductor with rhombohedral stacking-order, and the ferromagnetism originates from the partially occupied t2g orbitals. Different from previous understanding, the Mott metal-insulator transition of MnPS3 does not occur simultaneously with the spin-crossover but in a pressurized low-spin phase.

10.
RSC Adv ; 11(46): 28698-28703, 2021 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-35478555

RESUMO

Motivated by recent experimental observation [N. Z. Wang, et al., Inorg. Chem., 2019, 58, 9897], we investigated the electronic properties and chemical bonding in layered nitride-halide compounds ThNF and ThNCl using first-principles calculations to illustrate the interlayer interaction. The energy gaps and chemical valences of both compounds are in agreement with experimental data. The crystal orbital Hamiltonian population (COHP) and charge density differential analysis show that interlayer chemical bonding plays a more important role than that van der Waals interactions in ThNF and ThNCl, in contrast to isostructural ZrNCl and HfNCl. These results explain why it is difficult to intercalate ThNF and ThNCl with charged particles, as observed in experiments.

11.
J Am Chem Soc ; 141(43): 17166-17173, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31599579

RESUMO

Magnetism in the two-dimensional limit has become an intriguing topic for exploring new physical phenomena and potential applications. Especially, the two-dimensional magnetism is often associated with novel intrinsic spin fluctuations and versatile electronic structures, which provides vast opportunities in 2D material research. However, it is still challenging to verify candidate materials hosting two-dimensional magnetism, since the prototype systems have to be realized by using mechanical exfoliation or atomic layer deposition. Here, an alternative manipulation of two-dimensional magnetic properties via electrochemical intercalation of organic molecules is reported. Using tetrabutyl ammonium (TBA+), we synthesized a (TBA)Cr2Ge2Te6 hybrid superlattice with metallic behavior, and the Curie temperature is significantly increased from 67 K in pristine Cr2Ge2Te6 to 208 K in (TBA)Cr2Ge2Te6. Moreover, the magnetic easy axis changes from the ⟨001⟩ direction in Cr2Ge2Te6 to the ab-plane in (TBA)Cr2Ge2Te6. Theoretical calculations indicate that the drastic increase of the Curie temperature can be attributed to the change of magnetic coupling from a weak superexchange interaction in pristine Cr2Ge2Te6 to a strong double-exchange interaction in (TBA)Cr2Ge2Te6. These findings are the first demonstration of manipulation of magnetism in magnetic van der Waals materials by means of intercalating organic ions, which can serve as a convenient and efficient approach to explore versatile magnetic and electronic properties in van der Waals crystals.

12.
Sci Bull (Beijing) ; 64(10): 653-658, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-36659647

RESUMO

Superconductivity beyond electron-phonon mechanism is always twisted with magnetism. Based on a new field-effect transistor with solid ion conductor as the gate dielectric (SIC-FET), we successfully achieve an electric-field-controlled phase transition between superconductor and ferromagnetic insulator in (Li,Fe)OHFeSe. A dome-shaped superconducting phase with optimal Tc of 43 K is continuously tuned into a ferromagnetic insulating phase, which exhibits an electric-field-controlled quantum critical behavior. The origin of the ferromagnetism is ascribed to the order of the interstitial Fe ions expelled from the (Li,Fe)OH layers by gating-controlled Li injection. These surprising findings offer a unique platform to study the relationship between superconductivity and ferromagnetism in Fe-based superconductors. This work also demonstrates the superior performance of the SIC-FET in regulating physical properties of layered unconventional superconductors.

13.
Int Heart J ; 59(5): 1069-1076, 2018 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-30101846

RESUMO

Exercise preconditioning (EP) attenuates pathological cardiac hypertrophy by increasing the functional capacity of the cardiovascular system; however, the underlying molecular mechanisms remain unclear. MicroRNAs (miRNAs) play important roles in various physiological and pathological processes by regulating the expression of the targeted gene. In this study, we aimed to screen the miRNAs involved in EP-attenuating pathological cardiac hypertrophy. The histological and echocardiographic parameters assessment showed that pathological cardiac hypertrophy induced by transverse aortic constriction (TAC) was significantly alleviated in EP treated rats. The left ventricular tissues (n = 3) from Sham, TAC and EP + TAC groups were subjected to small RNA deep sequencing. A total of 570 known mature miRNAs and 530 putative novel miRNAs were detected. DEGseq analysis showed that there were 37 and 88 differentially expressed miRNAs in the comparisons of TAC versus Sham and EP + TAC versus TAC, respectively. Among them, EP treatment could relieve the expression changes of 32 miRNAs, which were supposed to be involved in EP-attenuating pathological cardiac hypertrophy. After miRNAs target genes prediction by miRDB algorithm, pathway analysis showed that the most frequently represented pathways were involved in Calcium signaling pathway and MAPK signaling pathway. The results would provide valuable clues to finding therapeutic targets for the treatment of pathological cardiac hypertrophy.


Assuntos
Cardiomegalia/patologia , Ventrículos do Coração/patologia , MicroRNAs/genética , Condicionamento Físico Animal/efeitos adversos , Animais , Sinalização do Cálcio/fisiologia , Cardiomegalia/diagnóstico por imagem , Cardiomegalia/metabolismo , Cardiomegalia/prevenção & controle , Ecocardiografia/métodos , Ventrículos do Coração/diagnóstico por imagem , Ventrículos do Coração/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Masculino , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Condicionamento Físico Animal/fisiologia , Ratos , Ratos Sprague-Dawley/genética , Transdução de Sinais/fisiologia
14.
Sci Bull (Beijing) ; 63(23): 1539-1544, 2018 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36751073

RESUMO

Different instabilities have been confirmed to exist in the three-dimensional (3D) electron gas when it is confined to the lowest Landau level in the extreme quantum limit. The recently discovered 3D topological semimetals offer a good platform to explore these phenomena due to the small sizes of their Fermi pockets, which means the quantum limit can be achieved at relatively low magnetic fields. In this work, we report the high-magnetic-field transport properties of the Dirac semimetal state in pressurized black phosphorus. Under applied hydrostatic pressure, the band structure of black phosphorus goes through an insulator-semimetal transition. In the high pressure topological semimetal phase, anomalous behaviors are observed on both magnetoresistance and Hall resistivity beyond the relatively low quantum limit field, which is demonstrated to indicate the emergence of an exotic electronic state hosting a density wave ordering. Our findings bring the first insight into the electronic interactions in black phosphorus under intense field.

15.
Oncotarget ; 8(12): 19684-19698, 2017 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-28160558

RESUMO

The plant homeodomain (PHD) finger-containing proteins have been implicated in many human diseases including cancer. In this study, we found that PHF14, a newly identified PHD finger protein, is highly expressed in lung cancer. The high expression level of PHF14 was associated with adenocarcinoma and poor survival in lung cancer patients. Knocking down PHF14 suppressed cancer cell growth and carcinogenesis, while over-expressing PHF14 promoted cell proliferation. During cell division, PHF14 directly bound to and co-localized with KIF4A (a nuclear motor protein involved in lung carcinogenesis) to form a functional complex. Similarly to the effect of KIF4A depletion, silencing PHF14 in several cell lines caused cell mitotic defects, prolonged M phase, and inhibited cell proliferation. What's more, these two proteins had a synergistic effect on cell proliferation and were significantly co-overexpressed in lung cancer tissues. Our data provide new insights into the biological significance of PHD finger proteins and imply that PHF14 may be a potential biomarker for lung cancer.


Assuntos
Adenocarcinoma/patologia , Carcinoma Pulmonar de Células não Pequenas/patologia , Transformação Celular Neoplásica/patologia , Cinesinas/metabolismo , Neoplasias Pulmonares/patologia , Mitose/fisiologia , Fatores de Transcrição/metabolismo , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Animais , Apoptose , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Proliferação de Células , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Feminino , Seguimentos , Regulação Neoplásica da Expressão Gênica , Humanos , Cinesinas/genética , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Taxa de Sobrevida , Fatores de Transcrição/genética , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
16.
Dig Liver Dis ; 49(1): 77-83, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27637154

RESUMO

BACKGROUND: The CYP2E1 protein is a monooxygenase with certain polymorphisms linked to liver cancer. However, results from individual studies remain controversial. AIMS: To evaluate CYP2E1 polymorphisms in liver carcinogenesis through meta-analysis. METHODS: All studies about CYP2E1 polymorphisms and liver cancer were retrieved from seven major databases. Original data from each study were pooled and re-analyzed. RESULTS: Total of 16 articles with 4862 cases were selected, including 1820 cases of liver cancer and 3042 cases of controls. The c1 allelic frequency in the cases and controls was 83.3% and 85.3%, respectively. Five genetic variations were compared: dominant c1c2/c2c2 vs. c1/c1 (OR=0.987 (0.853, 1.141)), homozygous c2c2 vs. c1c1 (OR=0.767 (0.526, 1.119)), heterozygous c1c2 vs. c1c1 (OR=1.005 (0.854, 1.182)), recessive c2c2 vs. c1c2/c2c2 (OR=0.771 (0.530, 1.122)), and different alleles c2 vs. c1 (OR=0.947 (0.828, 1.082)). Pooled data were further analyzed based on ethnicity, control sources, and HWE (Hardy-Weinberg equilibrium). These results from stratified groups were similar to that of nonstratified groups. CONCLUSIONS: Our meta-analysis results suggest that there is no evidence for a major role of CYP2E1 polymorphism in liver carcinogenesis, but do not rule out the possibility in certain cases.


Assuntos
Carcinogênese/genética , Citocromo P-450 CYP2E1/genética , Neoplasias Hepáticas/genética , Alelos , Frequência do Gene , Predisposição Genética para Doença , Humanos , Polimorfismo Genético
17.
Zhonghua Xin Xue Guan Bing Za Zhi ; 43(10): 894-9, 2015 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-26652992

RESUMO

OBJECTIVE: To observe the effect of exercise preconditioning (EP) on pressure overload-induced pathological cardiac hypertrophy and explore related mechanisms. METHODS: Ten-week-old male Sprague-Dawley rats (n = 80) were randomly divided into four groups via random number table method: sham, TAC, EP + sham and EP + TAC. Two EP groups were subjected to 4 weeks of treadmill training, and followed by sham and TAC operations. Eight weeks after the surgery, mean arterial pressure (MAP), cardiac morphology, mRNA expressions of the B-type natriuretic peptide (BNP) and heat shock protein (HSP) 70 and protein expression of the BNP, heat shock transcription factor 1 (HSF1), HSP70, nuclear factor κB (NF-κB) p65, and interleukin-2 (IL-2) were examined. RESULTS: (1) Pathological cardiac hypertrophy index: eight weeks after TAC, MAP, heart size, HW/BW, cross-sectional area of the cardiomyocytes (CSA) and mRNA and protein expressions of BNP in the LV were all significantly higher in the TAC and EP + TAC groups than respective sham groups (all P < 0.05). HW/BW, CSA, and mRNA and protein expressions of BNP in the LV were significantly lower in EP + TAC group than in TAC group (all P < 0.05). (2) mRNA and protein expressions of HSF1 and HSP70 and nuclear HSF1 levels were significantly downregulated post TAC, however, EP treatment significantly increased the expression of HSF1 and nuclear HSF1 levels in TAC rats (all P < 0.05). (3) mRNA and protein expressions of NF-κB p65 and IL-2 were significantly increased in the TAC and EP + TAC groups compared with the respective sham groups (all P < 0.05), which were significantly downregulated in EP + TAC group compared to TAC group (all P < 0.05). CONCLUSIONS: EP could effectively reduce the cardiac hypertrophic responses induced by TAC possibly through upregulating the expressions of HSF1 and HSP70 and inhibiting the expression of NF-κB p65 and its nuclear translocation.


Assuntos
Cardiomegalia , Transdução de Sinais , Animais , Proteínas de Ligação a DNA , Regulação para Baixo , Proteínas de Choque Térmico HSP70 , Fatores de Transcrição de Choque Térmico , Interleucina-2 , Masculino , Miócitos Cardíacos , Peptídeo Natriurético Encefálico , Condicionamento Físico Animal , RNA Mensageiro , Ratos , Ratos Sprague-Dawley , Fator de Transcrição RelA , Fatores de Transcrição
18.
Biochem Biophys Res Commun ; 460(3): 622-7, 2015 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-25804640

RESUMO

Pathological cardiac hypertrophy, often accompanied by hypertension, aortic stenosis and valvular defects, is typically associated with myocyte remodeling and cardiac dysfunction. Exercise preconditioning (EP) has been proven to enhance the tolerance of the myocardium to cardiac ischemia-reperfusion injury. However, the effects of EP in pathological cardiac hypertrophy are rarely reported. 10-wk-old male Sprague-Dawley rats (n = 80) were randomly divided into four groups: sham, TAC, EP + sham and EP + TAC. Two EP groups were subjected to 4 weeks of treadmill training, and the EP + TAC and TAC groups were followed by TAC operations. The sham and EP + sham groups underwent the same operation without aortic constriction. Eight weeks after the surgery, we evaluated the effects of EP by echocardiography, morphology, and histology and observed the expressions of the associated proteins. Compared with the respective control groups, hypertrophy-related indicators were significantly increased in the TAC and EP + TAC groups (p < 0.05). However, between the TAC and EP + TAC groups, all of these changes were effectively inhibited by EP treatment (p < 0.05). Furthermore, EP treatment upregulated the expression of HSF1 and HSP70, increased the HSF1 levels in the nuclear fraction, inhibited the expression of the NF-κB p65 subunit, decreased the NF-κB p65 subunit levels in the nuclear fraction, and reduced the IL2 levels in the myocardia of rats. EP could effectively reduce the cardiac hypertrophic responses induced by TAC and may play a protective role by upregulating the expressions of HSF1 and HSP70, activating HSF1 and then inhibiting the expression of NF-κB p65 and nuclear translocation.


Assuntos
Cardiomegalia/metabolismo , Proteínas de Ligação a DNA/fisiologia , Condicionamento Físico Animal , Fator de Transcrição RelA/fisiologia , Fatores de Transcrição/fisiologia , Animais , Sequência de Bases , Cardiomegalia/fisiopatologia , Primers do DNA , Fatores de Transcrição de Choque Térmico , Masculino , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase em Tempo Real
19.
Int J Clin Exp Pathol ; 8(1): 530-40, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25755743

RESUMO

Pathological cardiac hypertrophy, a common response of the heart to a variety of cardiovascular diseases, is typically associated with myocytes remodeling and fibrotic replacement, cardiac dysfunction. Exercise preconditioning (EP) increases the myocardial mechanical load and enhances tolerance of cardiac ischemia-reperfusion injury (IRI), however, is less reported in pathological cardiac hypertrophy. To determine the effect of EP in pathological cardiac hypertrophy, Male 10-wk-old Sprague-Dawley rats (n=30) were subjected to 4 weeks of EP followed by 4-8 weeks of pressure overload (transverse aortic constriction, TAC) to induce pathological remodeling. TAC in untrained controls (n=30) led to pathological cardiac hypertrophy, depressed systolic function. We observed that left ventricular wall thickness in end diastole, heart size, heart weight-to-body weight ratio, heart weight-to-tibia length ratio, cross-sectional area of cardiomyocytes and the reactivation of fetal genes (atrial natriuretic peptide and brain natriuretic peptide) were markedly increased, meanwhile left ventricular internal dimension at end-diastole, systolic function were significantly decreased by TAC at 4 wks after operation (P < 0.01), all of which were effectively inhibited by EP treatment (P < 0.05), but the differences of these parameters were decreased at 8 wks after operation. Furthermore, EP treatment inhibited degradation of IκBα, and decreased NF-κB p65 subunit levels in the nuclear fraction, and then reduced IL2 levels in the myocardium of rats subject to TAC. EP can effectively attenuate pathological cardiac hypertrophic responses induced by TAC possibly through inhibition of degradation of IκB and blockade of the NF-κB signaling pathway in the early stage of pathological cardiac hypertrophy.


Assuntos
Cardiomegalia/patologia , Miocárdio/patologia , Condicionamento Físico Animal/fisiologia , Animais , Fator Natriurético Atrial/metabolismo , Cardiomegalia/metabolismo , Cardiomegalia/prevenção & controle , Proteínas I-kappa B/metabolismo , Masculino , Miocárdio/metabolismo , Peptídeo Natriurético Encefálico/metabolismo , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/fisiologia
20.
J Heart Valve Dis ; 23(4): 458-62, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25803972

RESUMO

BACKGROUND AND AIM OF THE STUDY: Intra-aortic balloon pump (IABP) in heart valve surgical patients is associated with a higher mortality than coronary artery bypass grafting (CABG). The study aim was to analyze the early outcome of heart valve surgical patients requiring IABP support, and to assess the risk factors for early mortality. METHODS: Among a cohort of 5,786 patients undergoing heart valve replacement without CABG, 81 (1.4%) required IABP support. Data from these latter patients were collected and analyzed retrospectively, and univariate and multivariate logistic regression were applied to identify risk factors for early mortality in patients requiring IABP support. RESULTS: IABP was inserted in 30 patients intraoperatively, and in 51 patients postoperatively. The overall mortality was 50.6%. Mortality in the intraoperative IABP subgroup was significantly lower than in the postoperative IABP subgroup (26.7% versus 64.7%, p = 0.001). The independent risk factors for early mortality were: age increasing by 10 years (OR 1.906, 95% CI: 1.165-3.116, p = 0.010) and pulmonary hypertension (OR 4.153, 95% CI: 1.380-12.499, p = 0.011). Intraoperative IABP insertion (OR 0.297, 95% CI: 0.100-0.876, p = 0.028) was identified as a protective factor compared to postoperative insertion. CONCLUSION: The mortality of patients requiring IABP support after heart valve replacement was high. The efficacy of intraoperative IABP insertion was better than a postoperative mandatory use. Clearly, more attention should be paid to older patients or those with pulmonary hypertension, who may benefit less from IABP.


Assuntos
Implante de Prótese de Valva Cardíaca , Valvas Cardíacas/cirurgia , Balão Intra-Aórtico , Adulto , Fatores Etários , Feminino , Implante de Prótese de Valva Cardíaca/mortalidade , Humanos , Hipertensão Pulmonar/complicações , Período Intraoperatório , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Estudos Retrospectivos , Fatores de Risco , Resultado do Tratamento
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