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1.
Nano Lett ; 24(28): 8580-8586, 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-38967330

RESUMO

By using low-temperature scanning tunneling microscopy and spectroscopy (STM/STS), we observe in-gap states induced by Andreev tunneling through a single impurity state in a low carrier density superconductor (NaAlSi). The energy-symmetric in-gap states appear when the impurity state is located within the superconducting gap. In-gap states can cross the Fermi level, and they show X-shaped spatial variation. We interpret the in-gap states as a consequence of the Andreev tunneling through the impurity state, which involves the formation or breakup of a Cooper pair. Due to the low carrier density in NaAlSi, the in-gap state is tunable by controlling the STM tip-sample distance. Under strong external magnetic fields, the impurity state shows Zeeman splitting when it is located near the Fermi level. Our findings not only demonstrate the Andreev tunneling involving single electronic state but also provide new insights for understanding the spatially dependent in-gap states in low carrier density superconductors.

2.
J Ultrasound Med ; 42(2): 463-475, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36444908

RESUMO

OBJECTIVES: This study aims to determine the effect of low-intensity focused ultrasound (LIFU) in ischemic heart failure (IHF) and explore the potential neuroimmune mechanism. METHODS: Sprague-Dawley rats were subjected to ultrasound (US) with specific parameters, and electrocardiograms were recorded to analyze the effect of LIFU and/or vagal denervation on heart rate. Thereafter, myocardial infarction (MI) was induced by left anterior artery ligation, and LIFU was performed three times a day for 25 days after MI. Echocardiography, Masson staining, and ELISA were used to evaluate the effect of LIFU on the structure and function of the heart. Finally, ELISA, flow cytometry, qRT-PCR, and Western blot analysis were performed to determine the effect of LIFU on the inflammation and the expression of the cholinergic anti-inflammatory pathway (CAP)-related mediators. RESULTS: LIFU reduced heart rate in rats (control vs LIFU, P < .01), and vagotomy (VT) eliminated this effect of LIFU on heart rate (VT vs LIFU + VT, P > .01). LIFU-ameliorated IHF in terms of cardiac structure and function (MI vs MI + LIFU, P < .01), but VT abrogated the beneficial effect of LIFU (MI + VT vs MI + LIFU + VT, P > .01). After the treatment of LIFU, decreased levels of inflammatory cytokines, increased proportion of anti-inflammatory macrophages, and increased expression of CAP-related mediators (MI vs MI + LIFU, P < .01). CONCLUSIONS: LIFU ameliorates IHF whereas the CAP plays a promising role. LIFU has the potential to be a novel nonpharmacological and noninvasive therapy for the treatment of coronary artery disease and other cardiovascular diseases.


Assuntos
Insuficiência Cardíaca , Infarto do Miocárdio , Ratos , Animais , Neuroimunomodulação , Ratos Sprague-Dawley , Coração , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/metabolismo , Insuficiência Cardíaca/diagnóstico por imagem , Insuficiência Cardíaca/terapia
3.
Angew Chem Int Ed Engl ; 60(21): 11713-11717, 2021 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-33665956

RESUMO

Renal-clearable nanoparticles are typically fast eliminated through the free glomerular filtration, which show weak interaction with the renal compartments and negligible ultrasound signals, raising challenges in direct imaging of kidney diseases. Here, we report the ultrasmall renal-clearable luminescent gold nanoparticles (AuNPs) with both pH-induced charge reversal and aggregation properties, and discover that enhanced ultrasound contrast could be facilely acquired through the increased tubular reabsorption and in situ aggregation of AuNPs in renal tubule cells in injured kidneys. The tuning elimination pathway of the renal-clearable luminescent AuNPs is further demonstrated to provide a synergistical fluorescence and ultrasound imaging strategy for diagnosing early kidney injury with precise anatomical information.


Assuntos
Meios de Contraste/metabolismo , Corantes Fluorescentes/metabolismo , Nefropatias/diagnóstico por imagem , Nanopartículas Metálicas/química , Animais , Meios de Contraste/química , Meios de Contraste/farmacocinética , Feminino , Fluorescência , Corantes Fluorescentes/química , Corantes Fluorescentes/farmacocinética , Ouro/química , Rim/metabolismo , Rim/patologia , Nefropatias/metabolismo , Nefropatias/patologia , Camundongos Endogâmicos BALB C , Ondas Ultrassônicas , Ultrassonografia/métodos
4.
Proc Natl Acad Sci U S A ; 113(11): 2904-9, 2016 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-26929327

RESUMO

As a new type of topological materials, ZrTe5 shows many exotic properties under extreme conditions. Using resistance and ac magnetic susceptibility measurements under high pressure, while the resistance anomaly near 128 K is completely suppressed at 6.2 GPa, a fully superconducting transition emerges. The superconducting transition temperature Tc increases with applied pressure, and reaches a maximum of 4.0 K at 14.6 GPa, followed by a slight drop but remaining almost constant value up to 68.5 GPa. At pressures above 21.2 GPa, a second superconducting phase with the maximum Tc of about 6.0 K appears and coexists with the original one to the maximum pressure studied in this work. In situ high-pressure synchrotron X-ray diffraction and Raman spectroscopy combined with theoretical calculations indicate the observed two-stage superconducting behavior is correlated to the structural phase transition from ambient Cmcm phase to high-pressure C2/m phase around 6 GPa, and to a mixture of two high-pressure phases of C2/m and P-1 above 20 GPa. The combination of structure, transport measurement, and theoretical calculations enable a complete understanding of the emerging exotic properties in 3D topological materials under extreme environments.

5.
Cell Physiol Biochem ; 48(4): 1530-1542, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30071515

RESUMO

BACKGROUND/AIMS: Recent studies indicate that therapies targeting the vasculature can significantly sensitize tumors to radiation. Ultrasound-stimulated microbubbles (USMBs) are regarded as a promising radiosensitizer. In this study, we investigated the effect of USMBs on the sensitivity of nasopharyngeal carcinoma (NPC) to radiation. METHODS: Human NPC (CNE-2) cells and human umbilical vein endothelial cells (HUVECs) were exposed to radiation (0, 2, and 8 Gy) alone or in combination with USMBs. Cell viability and apoptosis were measured with the MTT assay and flow cytometry, respectively. The angiogenic activity of HUVECs was detected using matrigel tubule formation. The in vitro effects induced by these treatments were confirmed in vivo with xenograft models of CNE-2 cells in nude mice by examining vascular integrity using color Doppler flow imaging and cell survival using immunohistochemistry. Additionally, the in vivo and in vitro expressions of angiotensin II (ANG II) and its receptor (AT1R) were detected by immunohistochemistry and western blotting, respectively. With CNE-2 cells and HUVECs transfected with control, ANG II, or AT1R, perindopril (an inhibitor of angiotensin-converting enzyme) and candesartan (an inhibitor of AT1R) were used to verify the role of ANG II and AT1R in the radiosensitivity of tumor and endothelial cells by USMBs, by determining cell viability and apoptosis and angiogenic activity. RESULTS: In the NPC xenografts, USMBs slightly reduced blood flow and CD34 expression, increased tumor cell death and ANG II and AT1R expression, and significantly enhanced the effects of radiation. With CNE-2 cells and HUVECs, the USMBs further enhanced the inhibition of tumor cell viability and endothelial tubule formation and further enhanced the increase in ANG II and AT1R due to radiation. Furthermore, perindopril and candesartan significantly enhanced the inhibitory effect of radiation and USMBs on tumor cell growth and angiogenesis in vitro. CONCLUSIONS: We have demonstrated for the first time that USMB exposure can significantly enhance the destructive effect on NPC of radiation, and this effect might be further increased by ANG II and AT1R inhibition. Our findings suggest that USMBs can be used as a promising sensitizer of radiotherapy to treat NPC, and the clinical effect might be increased by ANG II and AT1R inhibition.


Assuntos
Meios de Contraste/química , Microbolhas/uso terapêutico , Angiotensina II/metabolismo , Animais , Antígenos CD34/metabolismo , Benzimidazóis/metabolismo , Compostos de Bifenilo , Carcinoma/metabolismo , Carcinoma/patologia , Carcinoma/radioterapia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/efeitos da radiação , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Meios de Contraste/farmacologia , Meios de Contraste/uso terapêutico , Feminino , Raios gama , Células Endoteliais da Veia Umbilical Humana , Humanos , Camundongos , Camundongos Nus , Carcinoma Nasofaríngeo , Neoplasias Nasofaríngeas/metabolismo , Neoplasias Nasofaríngeas/patologia , Neoplasias Nasofaríngeas/radioterapia , Perindopril/metabolismo , Receptor Tipo 1 de Angiotensina/metabolismo , Sonicação , Tetrazóis/metabolismo
6.
Clin Invest Med ; 39(1): E25-36, 2016 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-26833170

RESUMO

PURPOSE: Fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) is used to assess the need for angioplasty in vessels with intermediate blockages. The treatment outcomes of FFR-guided vs. conventional angiography-guided PCI were evaluated in patients with multi-vessel coronary artery disease (CAD). METHODS: Prospective and retrospective studies comparing FFR-guided vs. angiography-guided PCI in patients with multi-vessel CAD were identified from medical databases by two independent reviewers using the terms "percutaneous coronary intervention, fractional flow reserve, angiography, coronary heart disease, major adverse cardiac events (MACE) and myocardial infarction". The primary outcome was the number of stents placed, and the secondary outcomes were procedure time, mortality, myocardial infarction (MI) and MACE rates. RESULTS: Seven studies (three retrospective and four prospective), which included 49,517 patients, were included in this review. A total of 4,755 patients underwent FFR, while 44,697 received angiography-guided PCI. The mean patient age ranged from 58 to 71.7 years. The average number of stents used in FFR patients ranged from 0.3-1.9, and in angiography-guided PCI patients ranged from 0.7-2.7. Analysis indicated there was a greater number of stents placed in the angiography-guided group compared with the FFR group (pooled difference in means: -0.64, 95% confidence interval [CI]: -0.81 to -0.47, P < 0.001). There were no differences in the secondary outcomes between the two groups. CONCLUSIONS: Both procedures produce similar clinical outcomes, but the fewer number of stents used with FFR may have clinical as was as cost implications.


Assuntos
Angiografia Coronária , Doença da Artéria Coronariana , Infarto do Miocárdio , Intervenção Coronária Percutânea/efeitos adversos , Complicações Pós-Operatórias , Idoso , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/etiologia , Complicações Pós-Operatórias/diagnóstico por imagem , Complicações Pós-Operatórias/etiologia
7.
J Phys Condens Matter ; 36(16)2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38194718

RESUMO

The research on hydrogen-rich ternary compounds attract tremendous attention for it paves new route to room-temperature superconductivity at lower pressures. Here, we study the crystal structures, electronic structures, and superconducting properties of the ternary Ca-U-H system, combining crystal structure predictions withab-initiocalculations under high pressure. We found four dynamically stable structures with hydrogen clathrate cages: CaUH12-Cmmm, CaUH12-Fd-3m, Ca2UH18-P-3m1, and CaU3H32-Pm-3m. Among them, the Ca2UH18-P-3m1 and CaU3H32-Pm-3mare likely to be synthesized below 1 megabar. Thefelectrons in U atoms make dominant contribution to the electronic density of states around the Fermi energy. The electron-phonon interaction calculations reveal that phonon softening in the mid-frequency region can enhance the electron-phonon coupling significantly. TheTcvalue of Ca2UH18-P-3m1 is estimated to be 57.5-65.8 K at 100 GPa. Our studies demonstrate that introducing actinides into alkaline-earth metal hydrides provides possibility in designing novel superconducting ternary hydrides.

8.
Int J Cardiol ; 404: 131943, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38458386

RESUMO

BACKGROUND: Previous studies have demonstrated the efficacy of ultrasound-targeted microbubble destruction (UTMD) in the treatment of ischemic heart failure (HF). The purpose of this study was to explore the mechanism by which UTMD improves ischemic HF. METHODS: An ischemic heart failure model was established using Sprague-Dawley rats. Rats were randomly divided into 7 groups: sham group, HF group, HF + MB group, HF + ultrasound (US) group, HF + UTMD group, HF + UTMD+LY294002 group, and HF + LY294002 group. Serum BNP level and echocardiographic parameters were measured to evaluate cardiac function. PI3K/Akt/eNOS signaling pathway protein levels were detected by immunohistochemistry (IHC) and western blotting. The concentrations of nitrous oxide (NO) and ATP were detected by ELISA, and hematoxylin and eosin (HE) staining was used to evaluate myocardial tissue. RESULTS: UTMD rapidly improved ejection fraction (EF) (HF: 37.16 ± 1.21% vs. HF + UTMD: 46.31 ± 3.00%, P < 0.01) and fractional shortening (FS) (HF: 18.53 ± 0.58% vs. HF + UTMD: 24.05 ± 1.84%, P < 0.01) in rats with ischemic HF. UTMD activated the PI3K/AKT/eNOS signaling pathway (HF vs. HF + UTMD, P < 0.01) and promoted the release of NO and ATP (HF vs. HF + UTMD, both, P < 0.05). Inhibition of the PI3K/AKT/eNOS signaling pathway by LY294002 worsened EF (HF: 37.16 ± 1.21% vs. HF + LY294002: 32.73 ± 3.05%, P < 0.05), and the release of NO and ATP by UTMD (HF + UTMD vs. HF + UTMD+LY294002, P < 0.05). CONCLUSIONS: UTMD can rapidly improve cardiac function in ischemic HF by activating the PI3K/Akt/eNOS signaling pathway and promoting the release of NO and ATP.


Assuntos
Insuficiência Cardíaca , Proteínas Proto-Oncogênicas c-akt , Ratos , Animais , Ratos Sprague-Dawley , Proteínas Proto-Oncogênicas c-akt/metabolismo , Função Ventricular Esquerda , Microbolhas , Fosfatidilinositol 3-Quinases , Insuficiência Cardíaca/diagnóstico por imagem , Insuficiência Cardíaca/tratamento farmacológico , Trifosfato de Adenosina
9.
J Diabetes ; 16(6): e13567, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38769875

RESUMO

BACKGROUND: Reportedly, the stress-hyperglycemia ratio (SHR) is closely associated with poor prognosis in patients with severe acute disease. However, the community-dwelling may also be in a state of stress due to environmental exposure. Our study aimed to explore the association between SHR and all-cause mortality in the community-dwelling population. METHODS: A total of 18 480 participants were included out of 82 091 from the NHANES 1999-2014 survey. The Kaplan-Meier survival analyses were used to assess the disparities in survival rates based on SHR, and the log-rank test was employed to investigate the distinctions between groups. The multivariate Cox regression analysis and restricted cubic spline (RCS) analysis were performed to assess the association of SHR with all-cause mortality. A subgroup analysis was also conducted. RESULTS: A total of 3188 deaths occurred during a median follow-up period of 11.0 (7.7; 15.4) years. The highest risk for all-cause mortality was observed when SHR≤ 0.843 or SHR ≥0.986 (log-rank p < .001). After adjusting for the confounding factors, compared with subjects in the second SHR quartile (Q2), participants in the highest (Q4, adjusted hazard ratio [HR] 1.49, 95% confidence interval [CI] 1.28-1.73) and lowest quartiles (Q1, adjusted HR 1.37, 95% CI 1.16-1.60) have a higher probability of all-cause death. The RCS observed a dose-response U-shaped association between SHR and all-cause mortality. The U-shaped association between SHR and all-cause mortality was similar across subgroup analysis. CONCLUSIONS: The SHR was significantly associated with all-cause mortality in the community-dwelling population, and the relationship was U-shaped.


Assuntos
Hiperglicemia , Vida Independente , Inquéritos Nutricionais , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Vida Independente/estatística & dados numéricos , Hiperglicemia/mortalidade , Hiperglicemia/sangue , Hiperglicemia/epidemiologia , Adulto , Idoso , Causas de Morte , Fatores de Risco , Mortalidade/tendências , Estresse Fisiológico , Estados Unidos/epidemiologia , Prognóstico , Estimativa de Kaplan-Meier
10.
Adv Mater ; 36(27): e2401118, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38641859

RESUMO

As an empirical tool in materials science and engineering, the iconic phase diagram owes its robustness and practicality to the topological characteristics rooted in the celebrated Gibbs phase law free variables (F) = components (C) - phases (P) + 2. When crossing the phase diagram boundary, the structure transition occurs abruptly, bringing about an instantaneous change in physical properties and limited controllability on the boundaries (F = 1). Here, the sharp phase boundary is expanded to an amorphous transition region (F = 2) by partially disrupting the long-range translational symmetry, leading to a sequential crystalline-amorphous-crystalline (CAC) transition in a pressurized In2Te5 single crystal. Through detailed in situ synchrotron diffraction, it is elucidated that the phase transition stems from the rotation of immobile blocks [In2Te2]2+, linked by hinge-like [Te3]2- trimers. Remarkably, within the amorphous region, the amorphous phase demonstrates a notable 25% increase of the superconducting transition temperature (Tc), while the carrier concentration remains relatively constant. Furthermore, a theoretical framework is proposed revealing that the unconventional boost in amorphous superconductivity might be attributed to an intensified electron correlation, triggered by a disorder-augmented multifractal behavior. These findings underscore the potential of disorder and prompt further exploration of unforeseen phenomena on the phase boundaries.

11.
Exp Physiol ; 98(6): 1092-101, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23435903

RESUMO

The admittance and Wei's equation is a new technique for ventricular volumetry to determine pressure-volume relations that addresses traditional conductance-related issues of parallel conductance and field correction factor. These issues with conductance have prevented researchers from obtaining real-time absolute ventricular volumes. Moreover, the time-consuming steps involved in processing conductance catheter data warrant the need for a better catheter-based technique for ventricular volumetry. We aimed to compare the accuracy of left ventricular (LV) volumetry between the new admittance catheterization technique and transoesophageal real-time three-dimensional echocardiography (RT3DE) in a large-animal model. Eight anaesthetized pigs were used. A 7 French admittance catheter was positioned in the LV via the right carotid artery. The catheter was connected to an admittance control unit (ADVantage; Transonic Scisense Inc.), and data were recorded on a four-channel acquisition system (FA404; iWorx Systems). Admittance catheterization data and transoesophageal RT3DE (X7-2; Philips) data were simultaneously obtained with the animal ventilated, under neuromuscular blockade and monitored in baseline conditions and during dobutamine infusion. Left ventricular volumes measured from admittance catheterization (Labscribe; iWorx Systems) and RT3DE (Qlab; Philips) were compared. In a subset of four animals, admittance volumes were compared with those obtained from traditional conductance catheterization (MPVS Ultra; Millar Instruments). Of 37 sets of measurements compared, admittance- and RT3DE-derived LV volumes and ejection fractions at baseline and in the presence of dobutamine exhibited general agreement, with mean percentage intermethod differences of 10% for end-diastolic volumes, 14% for end-systolic volumes and 9% for ejection fraction; the respective intermethod differences between admittance and conductance in eight data sets compared were 11, 11 and 12%. Admittance volumes were generally higher than those obtained by RT3DE, especially among the larger ventricles. It is concluded that it is feasible to derive pressure-volume relations using admittance catheterization in large animals. This study demonstrated agreements between admittance and RT3DE to within 10-14% mean intermethod difference in the estimation of LV volumes. Further investigation will be required to examine the accuracy of volumes in largest ventricles, where intermethod divergence is greatest.


Assuntos
Volume Cardíaco/fisiologia , Cateterismo/métodos , Ecocardiografia Tridimensional/métodos , Coração/fisiopatologia , Função Ventricular Esquerda/fisiologia , Animais , Volume Cardíaco/efeitos dos fármacos , Artérias Carótidas/efeitos dos fármacos , Artérias Carótidas/fisiologia , Catéteres , Dobutamina/farmacologia , Coração/efeitos dos fármacos , Ventrículos do Coração/efeitos dos fármacos , Ventrículos do Coração/fisiopatologia , Suínos , Função Ventricular Esquerda/efeitos dos fármacos
12.
Adv Sci (Weinh) ; 10(35): e2301332, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37944509

RESUMO

Topological transition metal dichalcogenides (TMDCs) have attracted much attention due to their potential applications in spintronics and quantum computations. In this work, the structural and electronic properties of topological TMDCs candidate ZrTe2 are systematically investigated under high pressure. A pressure-induced Lifshitz transition is evidenced by the change of charge carrier type as well as the Fermi surface. Superconductivity is observed at around 8.3 GPa without structural phase transition. A typical dome-shape phase diagram is obtained with the maximum Tc of 5.6 K for ZrTe2 . Furthermore, the theoretical calculations suggest the presence of multiple pressure-induced topological quantum phase transitions, which coexists with emergence of superconductivity. The results demonstrate that ZrTe2 with nontrivial topology of electronic states displays new ground states upon compression.

13.
Front Cardiovasc Med ; 9: 899099, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35795368

RESUMO

With growing evidence in clinical practice, the understanding of coronary syndromes has gradually evolved out of focusing on the well-established link between stenosis of epicardial coronary artery and myocardial ischemia to the structural and functional abnormalities at the level of coronary microcirculation, known as coronary microvascular dysfunction (CMD). CMD encompasses several pathophysiological mechanisms of coronary microcirculation and is considered as an important cause of myocardial ischemia in patients with angina symptoms without obstructive coronary artery disease (CAD). As a result of growing knowledge of the understanding of CMD assessed by multiple non-invasive modalities, CMD has also been found to be involved in other cardiovascular diseases, including primary cardiomyopathies as well as heart failure with preserved ejection fraction (HFpEF). In the past 2 decades, almost all the imaging modalities have been used to non-invasively quantify myocardial blood flow (MBF) and promote a better understanding of CMD. Myocardial contrast echocardiography (MCE) is a breakthrough as a non-invasive technique, which enables assessment of myocardial perfusion and quantification of MBF, exhibiting promising diagnostic performances that were comparable to other non-invasive techniques. With unique advantages over other non-invasive techniques, MCE has gradually developed into a novel modality for assessment of the coronary microvasculature, which may provide novel insights into the pathophysiological role of CMD in different clinical conditions. Moreover, the sonothrombolysis and the application of artificial intelligence (AI) will offer the opportunity to extend the use of contrast ultrasound theragnostics.

14.
Quant Imaging Med Surg ; 12(10): 4852-4864, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36185055

RESUMO

Background: This study aimed to evaluate the multiple interactions between therapeutic ultrasound (TUS), microbubbles (MB), and recombinant tissue plasminogen activator (r-tPA) by using three-dimensional (3D) ultrasound to examine the impact of thrombolysis with r-tPA on epicardial recanalization and microcirculation in patients with acute ST-segment-elevation myocardial infarction (STEMI). Methods: Acute thrombotic occlusion of the left anterior descending (LAD) artery was induced in 32 Bama pigs, who were fed a high-cholesterol diet and randomized into four groups: (I) a 3D-sono-assisted-thrombolysis (3D/TUS + MB + r-tPA) group; (II) a 3D/TUS + MB group; (III) a full-dose r-tPA group; and (IV) a 3D/TUS alone group. Epicardial angiographic recanalization rate, microcirculation in the at-risk myocardium, ST-segment elevation on electrocardiogram, and changes in the at-risk myocardium and the myocardial infarct area were compared between the groups. Results: After treatment, distal LAD recanalization was observed in 87.5% (7/8) of pigs in the 3D/TUS + MB + r-tPA group, which was significantly higher than the rates observed in the 3D/TUS + MB (37.5%) and the full-dose r-tPA (50.0%) groups (all P<0.05). The average acoustic intensity in the 3D/TUS + MB + r-tPA group (193.78±10.15 dB) was also significantly higher than that in the 3D/TUS + MB (154.29±31.94 dB) and the r-tPA (141.42±28.31 dB) groups (all P<0.05). The decrease in ST-segment elevation in the 3D/TUS + MB + r-tPA group (1.31±1.22 mm) was significantly higher than that in the 3D/TUS + MB (5.38±1.77 mm) and the r-tPA (4.30±2.08 mm) groups (all P<0.05). Furthermore, the ratio of the infarcted myocardial area divided by the at-risk myocardial area was markedly lower in the 3D/TUS + MB + r-tPA group (0.51±0.14) than in the 3D/TUS + MB (0.69±0.28) and r-tPA (0.75±0.23) groups (all P<0.05). Conclusions: Three-dimensional sono-assisted-thrombolysis directly improves infarct-related recanalization rates, enhances microcirculation, reduces r-tPA dosage, and ameliorates the thrombolytic effect of r-tPA in acute STEMI.

15.
Radiology ; 260(2): 463-71, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21555346

RESUMO

PURPOSE: To evaluate whether microbubbles targeted to vascular cell adhesion molecule-1 (VCAM-1) (CD106) coupled with a magnetic guidance system could improve the efficacy of contrast-enhanced molecular ultrasonography (US) of atherosclerosis in the aorta. MATERIALS AND METHODS: The animal research committee at Southern Medical University approved all experiments. Adherence of magnetic VCAM-1-targeted microbubbles, control inactive magnetic microbubbles, and nonmagnetic VCAM-1-targeted microbubbles to VCAM-1-Fc was determined in vitro by using a flow chamber at variable shear stress (1-24 dyne/cm(2)) under magnetic field guidance. Attachment of microbubbles under magnetic field guidance was determined in vivo with fluorescent microscopy and contrast-enhanced US of the abdominal aorta in wild-type (C57BL/6) or apolipoprotein E (APOE)-deficient mice on a regular or hypercholesterolemic diet. General factorial analysis of variance was used to compare the targeted effect of the microbubbles among different animal groups to identify significant differences. RESULTS: Attachment was noted for magnetic and nonmagnetic microbubbles but not for inactive magnetic microbubbles; firm attachment at high shear stress (16-20 dyne/cm(2)) was achieved only with magnetic microbubbles. Fluorescence intensity and video intensity were significantly higher in magnetic microbubbles with magnetic field guidance than in inactive magnetic microbubbles and nonmagnetic microbubbles (P < .05). Video intensity from retained magnetic microbubbles in APOE-deficient mice was significantly greater than that in wild-type mice (mean video intensity for APOE-deficient mice: 28.25 [interquartile range, or IQR, 26.55-29.20] with a hypercholesterolemic diet and 16.10 [IQR, 14.15-18.75] with a regular diet; mean video intensity for wild-type mice: 9.55 [IQR, 8.85-10.5] with a hypercholesterolemic diet and 2.90 [IQR, 1.25-3.85] with a regular diet; P < .001). CONCLUSION: Use of a magnetic targeted microbubble system results in greater attachment to endothelial VCAM-1 in atherosclerotic aortas in conditions of high shear stress and improved detection of early inflammatory changes of atherosclerosis.


Assuntos
Doenças da Aorta/diagnóstico por imagem , Doenças da Aorta/metabolismo , Aterosclerose/diagnóstico por imagem , Aterosclerose/metabolismo , Meios de Contraste/metabolismo , Microbolhas , Imagem Molecular/métodos , Molécula 1 de Adesão de Célula Vascular/metabolismo , Análise de Variância , Animais , Magnetismo , Camundongos , Camundongos Mutantes , Microscopia de Fluorescência , Estatísticas não Paramétricas , Ultrassonografia
16.
Ultrasound Med Biol ; 47(4): 1014-1023, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33487472

RESUMO

Ultrasound-mediated microbubble cavitation improves perfusion in chronic limb and myocardial ischemia. The purpose of this study was to determine the effects of ultrasound-mediated microbubble cavitation in acute limb ischemia and investigate the mechanism of action. The animal with acute hindlimb ischemia was established using male Sprague-Dawley rats. The rats were randomly divided into three groups: intermittent high-mechanical-index ultrasound pulses combined with microbubbles (ultrasound [US] + MB group), US alone (US group) and MB alone (MB group). Both hindlimbs were treated for 10 min. Contrast ultrasound perfusion imaging of both hindlimbs was performed immediately and 5, 10, 15, 20 and 25 min after treatment. The role of the nitric oxide (NO) pathway in increasing blood flow in acutely ischemic tissue was evaluated by inhibiting endothelial nitric oxide synthase (eNOS) with Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME). In the US + MB group, microvascular blood volume and microvascular blood flow of the ischemic hindlimb were significantly increased after treatment (both p values <0.05), while the microvascular flux rate (ß) increased, but not significantly (p > 0.05). The increases were observed immediately after treatment, and had dissipated by 25 min. Changes in the US and MB groups were minimal. Inhibitory studies indicated cavitation increased phospho-eNOS concentration in ischemic hindlimb muscle tissue, and the increase was significantly inhibited by L-NAME (p < 0.05). Ultrasound-mediated microbubble cavitation transiently increases local perfusion in acutely ischemic tissue, mainly by improving microcirculatory perfusion. The eNOS/NO signaling pathway appears to be an important mediator of the effect.


Assuntos
Isquemia/terapia , Microbolhas/uso terapêutico , Microcirculação/efeitos da radiação , Óxido Nítrico Sintase Tipo III/metabolismo , Óxido Nítrico/metabolismo , Terapia por Ultrassom , Animais , Inibidores Enzimáticos/farmacologia , Membro Posterior/irrigação sanguínea , Isquemia/diagnóstico por imagem , Isquemia/patologia , Isquemia/fisiopatologia , Masculino , Microcirculação/fisiologia , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/metabolismo , NG-Nitroarginina Metil Éster/farmacologia , Óxido Nítrico/antagonistas & inibidores , Fosforilação , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Fluxo Sanguíneo Regional , Transdução de Sinais , Ultrassonografia
17.
Zhonghua Zhong Liu Za Zhi ; 32(9): 655-8, 2010 Sep.
Artigo em Zh | MEDLINE | ID: mdl-21122377

RESUMO

OBJECTIVE: To assess the feasibility of usage of microbubbles conjugated with RGD peptides and contrast enhanced ultrasound (CEU) in detection of tumor angiogenesis. METHODS: Lipid microbubbles (MB) were prepared, and the RGD peptides were covalently conjugated to the lipid shell of MB (MB(RGD)). Six nude mice with tumor created by dorsal inoculation of HepG2 tumor cells were used as the test group. Six nude mice without tumor were served as the control group. 10 minutes after bolus injection of MB and MB(RGD) randomly (30 min interval) via a tail vein catheter, CEU was performed on the tumors of the test group and the thigh skeletal muscles of control group. The video intensity (VI) of tumors and the skeletal muscles were measured. The tumors and the skeletal muscles were harvested for immunohistochemical examination. RESULTS: Only a slight contrast enhancement of the tumor was seen with MB, and the VI was 5.33 ± 1.71. While a remarkable enhancement of the tumor was observed after injection of MB(RGD). The VI was up to 17.03 ± 3.58, 3.18 folds higher as compared with that obtained by injection of MB (P < 0.05). As expected, there were no obvious contrast enhancement of the skeletal muscles with both MB(RGD) and MB. There was a high expression of αvß3-integrin in tumor neovascular endothelium, however, no apparent expression of αvß3-integrin was observed in the skeletal muscle vascular endothelium. CONCLUSION: CEU with MB(RGD) can be used to effectively evaluate the angiogenesis of tumors, and it may greatly contribute to the early judgement of the nature of tumor.


Assuntos
Integrina alfaVbeta3/metabolismo , Neoplasias Hepáticas/irrigação sanguínea , Neoplasias Hepáticas/diagnóstico por imagem , Neovascularização Patológica/diagnóstico por imagem , Oligopeptídeos , Animais , Linhagem Celular Tumoral , Meios de Contraste , Endotélio Vascular/diagnóstico por imagem , Endotélio Vascular/metabolismo , Feminino , Humanos , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Camundongos Nus , Microbolhas , Músculo Esquelético/irrigação sanguínea , Transplante de Neoplasias , Neovascularização Patológica/metabolismo , Neovascularização Patológica/patologia , Ultrassom/métodos , Ultrassonografia
18.
Zhonghua Yi Xue Za Zhi ; 89(24): 1698-701, 2009 Jun 23.
Artigo em Zh | MEDLINE | ID: mdl-19957530

RESUMO

OBJECTIVE: To assess the feasibility of evaluating myocardial ischemia-reperfusion injury in mouse with targeted myocardial contrast echocardiography (MCE). METHODS: Phospholipid microbubbles targeted to P-selectin (MBp) and control microbubbles (MBc) were created by conjugating monoclonal antibody against murine P-selectin or isotype control antibody with the lipid shell via "avidin-biotin" bridging. Ten mice with myocardial ischemia-reperfusion were injected intravenously of MBp and MBc in a random order with a 30 min interval. After 5 min of intravenous injection of microbubble, targeted MCE imaging was performed in all mice. And then the video intensity (VI) was determined. RESULTS: A significant ultrasonic enhancement was observed in ischemic region of MBp-group. Increment in VI value of ischemic region in MBp-group was great and it amounted to (26.0 +/- 6.2) U. However, increment in VI value of ischemic region in MBc-group was minor and it was merely (9.1 +/- 0.9) U. Difference was evident in ischemic region between of two groups (P < 0.05). In both MBp-group and MBc-group, the VI value of ischemic region was significantly greater than that of non-ischemic region (6.5 +/- 1.0) U vs (6.4 +/- 0.8) U (P < 0.05). There was no obvious difference in the VI of non-ischemic region between two groups. CONCLUSION: Molecular imaging of P-selectin with targeted contrast echocardiography can effectively evaluate myocardial ischemia-reperfusion injury.


Assuntos
Eletrocardiografia/métodos , Traumatismo por Reperfusão Miocárdica/diagnóstico por imagem , Selectina-P , Animais , Feminino , Masculino , Camundongos , Camundongos Endogâmicos , Ultrassonografia
20.
J Am Soc Echocardiogr ; 30(3): 270-281, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28049598

RESUMO

BACKGROUND: Myocardial perfusion (MP) imaging during stress myocardial contrast echocardiography (MCE) improves the detection of coronary artery disease (CAD). However, its prognostic value to predict cardiac events in patients with known or suspected CAD is still undefined. METHODS: A search was conducted for single- or multicenter prospective studies that evaluated the prognostic value of stress MCE in patients with known or suspected CAD. A database search was performed through June 2015. Effect sizes of relative risk ratios (RRs) with their corresponding 95% CIs were used to evaluate the association between the occurrence of total cardiac events (cardiac death, nonfatal myocardial infarction, coronary revascularization) and hard cardiac events (cardiac death and nonfatal myocardial infarction) in subjects with normal and abnormal MP measured by MCE. The Cochran Q statistic and the I2 statistic were used to assess heterogeneity. RESULTS: A comprehensive literature search of the MEDLINE, Google Scholar, Cochrane, and Embase databases identified 11 studies enrolling a total of 4,045 patients. The overall analysis of RRs revealed that patients with abnormal MP were at higher risk for total cardiac events compared with patients with normal MP (RR, 5.58; 95% CI, 3.64-8.57; P < .001), with low heterogeneity among trials (I2 = 48.15%, Q = 7.71, P = .103). Similarly, patients with abnormal MP were at higher risk for hard cardiac events compared with patients with normal MP (RR, 4.99; 95% CI, 1.75-14.32; P = .003), with significant heterogeneity among trials (I2 = 81.48%, Q = 21.59, P < .001). CONCLUSIONS: The results of this meta-analysis suggest that MP assessment using stress MCE is an effective prognostic tool for predicting the occurrence of cardiac events in patients with known or suspected CAD.


Assuntos
Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/mortalidade , Morte Súbita Cardíaca/epidemiologia , Ecocardiografia sob Estresse/estatística & dados numéricos , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/mortalidade , Imagem de Perfusão do Miocárdio/estatística & dados numéricos , Idoso , Causalidade , Comorbidade , Ecocardiografia sob Estresse/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Imagem de Perfusão do Miocárdio/métodos , Prevalência , Prognóstico , Modelos de Riscos Proporcionais , Medição de Risco/métodos , Análise de Sobrevida
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