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1.
Echocardiography ; 38(11): 1959-1965, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34585775

RESUMO

Pulmonary artery and pulmonary valve sarcoma are malignant and very rare vascular tumors with aggressive clinical course and very poor outcomes. Patients affected by coronavirus disease of 2019 (COVID-19) are at a higher risk for thromboembolism complication. We describe a young woman with a history of coronavirus pneumonia and progressive dyspnea, hemodynamic disturbance, edema with initial evaluation, and clinical diagnosis of pulmonary thromboembolism. But further imaging study and pathology demonstrated giant sarcoma of pulmonary valve, obstructing pulmonary valve and extending to right ventricular outflow tract and main of pulmonary artery.


Assuntos
COVID-19 , Embolia Pulmonar , Valva Pulmonar , Sarcoma , Neoplasias Vasculares , Feminino , Humanos , Artéria Pulmonar , Embolia Pulmonar/diagnóstico por imagem , Valva Pulmonar/diagnóstico por imagem , SARS-CoV-2
2.
Med Arch ; 72(1): 22-25, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29416213

RESUMO

BACKGROUND: Right ventricular infarction (RVI) develops in 30-50% of patients with inferior wall infarction (IWI). The rates of mortality, morbidity, and complications in these patients are greater than in the patients without RVI. We compared the tissue Doppler imaging (TDI) indices between a group of patients with IWI and RVI, with a similar group of patients who had IWI alone to investigate the application of TDI indices in the evaluation and detection of right ventricular function. MATERIAL AND METHODS: We studied 49 patients with first acute IWI in two groups. Group 1 (N=24) were patients with IWI and RVI while group 2 consisted of patients with IWI alone (N=25), based on standard electrocardiogram criteria. The peak systolic (Sm), peak early (Em) and late (Am) diastolic velocities, and Em/Am ratio were obtained from the apical four chamber view, at the lateral side of the tricuspid annulus. We measured trans-tricuspid early (ET) and peak (AT) filling velocity, ET/AT ratio, right ventricular end diastolic diameter (RVEDD), and tricuspid annular plane systolic excursion (TAPSE) by M-mode TDI projected at the long axis of parasternal view. RESULTS: The RVEDD and E/Em ratio were increased, while the TAPSE was significantly decreased in the patients with RVI as compared to those without RVI (4.7± 0.6 vs. 3.1±0.2 cm; p < 0.005, 5.6±2.21 Vs 4.5±1.2; p<0.006 and 1.7±0.4 vs. 2.3±0.5 cm; p <0.0001, respectively). However, the other statistically measured parameters were not significantly different between these groups. CONCLUSION: The measurement of RVEDD, E/Em ratio, and TAPSE, as right ventricular myocardial systolic and diastolic parameters by pulse wave TDI could be used to objectively assess the status of RV condition in patients with first acute IWI.


Assuntos
Ecocardiografia Doppler/métodos , Voluntários Saudáveis/estatística & dados numéricos , Infarto Miocárdico de Parede Inferior/diagnóstico por imagem , Função Ventricular Direita/fisiologia , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
3.
Acta Cardiol ; 71(1): 47-54, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26853253

RESUMO

OBJECTIVES: The purpose of our study was to assess the value of aVR ST-segment elevation (STE) during acute non ST-segment elevation myocardial infarction (NSTEMI) or unstable angina. BACKGROUND: STE in lead aVR has been associated with severe coronary lesions in patients with acute coronary syndromes. However, there are conflicting data regarding the prognostic significance of this finding. METHODS: We evaluated the initial electrocardiogram (ECG) in 129 patients admitted to our hospital with acute NSTEMI or unstable angina without STE in leads other than aVR or V1. STE in aVR lead was measured and echocardiography and coronary angiography were performed within 48-72 hours after hospitalization. RESULTS: Overall, 40.3% (52 patients) had more than 0.05 mv STE in lead aVR. These patients had an increased prevalence of ST ≥ 1 mm in lead V1, a more frequent and extensive ST-segment depression (STD) in other leads, a higher prevalence of anterior and lateral STD and a lower frequency of isolated negative T waves. It was also strongly associated with cardiac enzyme rising and a trend toward higher 3-month mortality. Furthermore, patients with STE in lead aVR were more likely to have three-vessel or multivessel disease, higher Gensini score of the coronary arteries, lower left ventricular ejection fraction (LVEF) and higher incidence of mitral regurgitation (MR). CONCLUSIONS: Our study showed that among ECG markers, the sole criterion STE in lead aVR was independently associated with atherosclerosis severity and decreased LVEF. Also, it was significantly associated with the presence of MR.


Assuntos
Síndrome Coronariana Aguda/diagnóstico , Angina Instável/diagnóstico , Angiografia Coronária , Creatina Quinase Forma MB/sangue , Ecocardiografia , Eletrocardiografia , Infarto do Miocárdio/diagnóstico , Troponina I/sangue , Síndrome Coronariana Aguda/sangue , Síndrome Coronariana Aguda/mortalidade , Síndrome Coronariana Aguda/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Angina Instável/sangue , Angina Instável/mortalidade , Angina Instável/fisiopatologia , Biomarcadores/sangue , Estudos de Coortes , Angiografia Coronária/métodos , Feminino , Sistema de Condução Cardíaco/fisiopatologia , Humanos , Irã (Geográfico)/epidemiologia , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/sangue , Infarto do Miocárdio/mortalidade , Infarto do Miocárdio/fisiopatologia , Prevalência , Reprodutibilidade dos Testes , Fatores de Risco
4.
Scott Med J ; 60(2): e14-6, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25630505

RESUMO

Isolated single coronary artery is an extremely rare anomaly with an incidence of 0.024% to 0.066% which may be associated with other congenital anomalies. This report describes a 50-year-old woman who was referred with recurrent chest discomfort and was diagnosed with anomalous origin of the right coronary artery from the left circumflex coronary artery.


Assuntos
Angiografia Coronária , Anomalias dos Vasos Coronários/complicações , Anomalias dos Vasos Coronários/diagnóstico por imagem , Tomografia Computadorizada Multidetectores , Dor no Peito/etiologia , Feminino , Humanos , Pessoa de Meia-Idade
5.
Echocardiography ; 31(6): E177-80, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24646094

RESUMO

Double-outlet right ventricle (DORV), a clinically important congenital heart disease, occurs in 1-3% of persons with congenital heart disease. It may occur as an isolated cardiac defect, together with other cardiac lesions, or in association with extracardiac anomalies. Other rare cardiac anomalies include an anomalous muscle bundle (AMB) in the right ventricular outflow tract (RVOT) and an accessory tricuspid valve leaflet. We report a very rare case of concomitant DORV, AMB in the RVOT and accessory tricuspid valve leaflet in a 17-year-old male patient. The patient eventually died from severe decompensated heart failure. To the best of our knowledge, such a case has not been previously reported in the literature.


Assuntos
Anormalidades Múltiplas/diagnóstico por imagem , Ventrículos do Coração/anormalidades , Ventrículos do Coração/diagnóstico por imagem , Valva Tricúspide/anormalidades , Valva Tricúspide/diagnóstico por imagem , Obstrução do Fluxo Ventricular Externo/diagnóstico por imagem , Obstrução do Fluxo Ventricular Externo/etiologia , Adolescente , Diagnóstico Diferencial , Ecocardiografia/métodos , Humanos , Masculino , Doenças Raras/diagnóstico por imagem
6.
Echocardiography ; 30(4): E98-101, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23360092

RESUMO

Single ventricle defects, including inflow emptying into 1 ventricle, occur at an incidence of 0.05-0.1 per 10,000 live births. The association of total anomalous pulmonary venous drainage (TAPVD) with single ventricle defects is a risk factor for poor outcome. Conversely, common atrium, a rare congenital anomaly, is an endocardial cushion defect. We present a rare case of an unoperated patient with coincidence of a single ventricle defect, TAPVD with direct drainage from the pulmonary veins into the superior vena cava, and common atrium. To the best of our knowledge, such a case has not been previously reported in the literature.


Assuntos
Anormalidades Múltiplas/diagnóstico por imagem , Átrios do Coração/diagnóstico por imagem , Ventrículos do Coração/anormalidades , Artéria Pulmonar/anormalidades , Veia Cava Superior/anormalidades , Adulto , Diagnóstico Diferencial , Átrios do Coração/anormalidades , Ventrículos do Coração/diagnóstico por imagem , Humanos , Masculino , Artéria Pulmonar/diagnóstico por imagem , Doenças Raras/diagnóstico por imagem , Ultrassonografia , Veia Cava Superior/diagnóstico por imagem
7.
Echocardiography ; 30(5): E132-5, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23488590

RESUMO

Pulmonary agenesis is characterized by undeveloped pulmonary vessels, bronchi as well as lung parenchyma and is a rare congenital anomaly with unknown etiology. It is usually diagnosed during childhood. Nearly, one third of these patients have concomitant congenital heart diseases. While more than 50% of these patients die before the age of 5 years, some other patients may be asymptomatic throughout their life. On the other hand, common atrium, another rare congenital anomaly, is characterized by complete absence of the atrial septum and is usually accompanied by atrioventricular valve malformations. An 18-year-old male presented with concomitant pulmonary agenesis and common atrium and had not undergone surgery due to high risk for mortality.


Assuntos
Anormalidades Múltiplas/diagnóstico , Ecocardiografia Doppler/métodos , Átrios do Coração/anormalidades , Cardiopatias Congênitas/diagnóstico , Pneumopatias/diagnóstico , Anormalidades Múltiplas/diagnóstico por imagem , Adolescente , Fatores Etários , Eletrocardiografia/métodos , Átrios do Coração/diagnóstico por imagem , Cardiopatias Congênitas/diagnóstico por imagem , Defeitos dos Septos Cardíacos/diagnóstico , Defeitos dos Septos Cardíacos/diagnóstico por imagem , Humanos , Irã (Geográfico) , Pulmão/anormalidades , Pulmão/diagnóstico por imagem , Pneumopatias/diagnóstico por imagem , Masculino , Monitorização Fisiológica , Doenças Raras , Medição de Risco
8.
Clin Case Rep ; 11(10): e7958, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37780927

RESUMO

Systemic lupus erythematosus (SLE) can have various manifestations. Although cardiac involvement is very common in SLE patients, a severe acute pericarditis as the first manifestation of SLE in a male patient is relatively rare. A 36-year-old male was admitted to our hospital with acute pericarditis, large circumferential fibrinous pericarditis, and major criteria of a high-risk case of acute pericarditis. After a complete investigation, the underlying disease was revealed to be SLE. All of his symptoms were completely resolved after 6 weeks of treatment with non-steroidal anti-inflammatory drugs and corticosteroids with no need for a pericardiocentesis. Patients with acute fibrinous pericarditis should be considered and precisely investigated for multiorgan autoimmune process such as SLE, to avoid unnecessary intervention, and minimize the risk of recurrence and chronicity of the condition.

9.
Egypt Heart J ; 75(1): 28, 2023 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-37060533

RESUMO

BACKGROUND: ST-segment elevation myocardial infarction (STEMI) is usually caused by a rupture in the atherosclerotic plaque, followed by platelet aggregation which ultimately leads to acute coronary artery occlusion. So far, few studies have investigated the effect of maintenance dose of Eptifibatide (glycoprotein IIb/IIIa inhibitor) in STEMI patients who underwent primary percutaneous coronary intervention (PPCI). Therefore, in this study, we investigated the effect of maintenance dose of Eptifibatide in patients with STEMI who underwent PPCI. 264 patients who had acute chest pain suggestive of STEMI were entered in the study. All patients received the same dose of bolus dose of Eptifibatide in the cardiac catheterization laboratory. Then the patients were randomly divided into two groups, one group (n = 147) received a maintenance dose of intravenous Eptifibatide (infusion of 2 µg/kg/min) and the other group (n = 117) did not receive this treatment. Standard medical treatment of STEMI after PPCI was performed based on guidelines and the same in both groups. All patients were evaluated 1, 2, and 3 months after the start of treatment in terms of predicted outcomes. RESULTS: The occurrence of 3-month major adverse cardiovascular events (MACE) between the case and control groups did not have a statistically significant difference (28.6% versus 35.0%; P value: 0.286). Also, investigations showed that the rate of re-infarction (P value: 0.024) and target lesion revascularization (P value: 0.003) was significantly lower in the group that received Eptifibatide infusion. CONCLUSIONS: Eptifibatide maintenance dose infusion in patients who undergo PPCI in the context of STEMI, does not significantly reduce MACE, although it does significantly reduce re-infarction and target lesion revascularization. It also does not increase the risk of bleeding and cerebrovascular events.

10.
J Tehran Heart Cent ; 18(3): 154-169, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38146412

RESUMO

Background: Many studies have evaluated thromboembolic events in COVID-19 patients, and most of them have reported a high estimation of the prevalence of such events. The present study sought to evaluate the prevalence of thromboembolic events in patients with COVID-19. Methods: This study is a systematic review with meta-analysis that investigated thromboembolic events in patients with COVID-19 from the start of the pandemic to August 31, 2021. The 4 main databases for collecting articles were Medline, Scopus, Google Scholar, and Web of Science. Deep vein thrombosis, pulmonary embolism, arterial thrombosis, and the overall rate of thromboembolic events were considered primary outcomes. Results: In a total of 63 studies (104 920 patients with COVID-19), the overall thrombosis rate was 21% (95% CI, 18% to 25%), the rate of deep vein thrombosis was 20% (95% Cl, 16% to 25%), the rate of pulmonary embolism was 8% (95% Cl, 6% to 10%), and the rate of arterial thrombosis was 5% (95% Cl, 3% to 7%). The prevalence of all primary outcomes in critically ill patients admitted to the intensive care unit (ICU) was significantly higher (P<0.05). In older patients, the prevalence of overall thrombosis, pulmonary embolism, or deep vein thrombosis was significantly higher (P<0.05). Conclusion: This study showed that COVID-19 increases the risk of thromboembolic events, especially in elderly and critically ill patients admitted to the ICU. Therefore, more strategies are needed to prevent thromboembolic events in patients with COVID-19, especially in ICU-admitted and elderly patients.

11.
J Innov Card Rhythm Manag ; 14(12): 5697-5702, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38155722

RESUMO

Although myocardial infarction (MI) is a reversible cause of atrioventricular (AV) block, the association of ischemia other than MI with AV block is unclear. The purpose of this study is to investigate this relationship. Among patients nominated for pacemaker implantation due to AV block in two centers from 2017-2020, 120 patients with significant coronary artery disease (CAD) in angiography were included in the study. Patients were divided into two equal groups based on their CAD treatment approach: drug therapy and revascularization. Coronary lesions were divided into three types based on location: left anterior descending artery (type 1), dominant coronary with AV node branch (type 2), and a combination of both (type 3). After coronary disease treatment, all patients were followed up with for 14 months, and AV block reversibility was assessed. There were 7 cases of block reversibility in the revascularization group (11.7%) and 1 case in the medical group (1.7%), which differed significantly (P = .02). A history of acute coronary syndrome, smoking, opium use, chronic kidney disease, hypertension, age, sex, and chronic obstructive pulmonary disease were not significantly associated with reversible block. Also, the type of coronary obstruction had no significant relationship with block reversibility (P = .3, .5, and .8 for type 1, type 2, and type 3, respectively). Hibernation due to ischemia can be a reversible cause of an AV blockage. Therefore, it is recommended that significant coronary artery lesions be revascularized before pacemaker implantation.

12.
J Mater Chem B ; 10(48): 9944-9967, 2022 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-36415922

RESUMO

Synthesis, design, characterization, and application of carbon-based nanostructures (CBNSs) as drug carriers have attracted a great deal of interest over the past half of the century because of their promising chemical, thermal, physical, optical, mechanical, and electrical properties and their structural diversity. CBNSs are well-known in drug delivery applications due to their unique features such as easy cellular uptake, high drug loading ability, and thermal ablation. CBNSs, including carbon nanotubes, fullerenes, nanodiamond, graphene, and carbon quantum dots have been quite broadly examined for drug delivery systems. This review not only summarizes the most recent studies on developing carbon-based nanostructures for drug delivery (e.g. delivery carrier, cancer therapy and bioimaging), but also tries to deal with the challenges and opportunities resulting from the expansion in use of these materials in the realm of drug delivery. This class of nanomaterials requires advanced techniques for synthesis and surface modifications, yet a lot of critical questions such as their toxicity, biodistribution, pharmacokinetics, and fate of CBNSs in biological systems must be answered.


Assuntos
Técnicas Biossensoriais , Nanoestruturas , Nanotubos de Carbono , Neoplasias , Humanos , Nanotubos de Carbono/química , Distribuição Tecidual , Técnicas Biossensoriais/métodos , Nanoestruturas/química , Sistemas de Liberação de Medicamentos/métodos , Neoplasias/tratamento farmacológico
13.
Carbohydr Polym ; 275: 118624, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34742405

RESUMO

The biodegradability and mechanical properties of polysaccharides are dependent on their architecture (linear or branched) as well as their crystallinity (size of crystals and crystallinity percent). The amount of crystalline zones in the polysaccharide significantly governs their ultimate properties and applications (from packaging to biomedicine). Although synthesis, characterization, and properties of polysaccharides have been the subject of several review papers, the effects of crystallization kinetics and crystalline domains on the properties and application have not been comprehensively addressed. This review places focus on different aspects of crystallization of polysaccharides as well as applications of crystalline polysaccharides. Crystallization of cellulose, chitin, chitosan, and starch, as the main members of this family, were discussed. Then, application of the aforementioned crystalline polysaccharides and nano-polysaccharides as well as their physical and chemical interactions were overviewed. This review attempts to provide a complete picture of crystallization-property relationship in polysaccharides.


Assuntos
Celulose/química , Quitina/química , Quitosana/química , Polissacarídeos/química , Amido/química , Cristalização , Cinética , Polímeros/química , Polissacarídeos/metabolismo
14.
ACS Appl Mater Interfaces ; 14(9): 11124-11143, 2022 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-35227057

RESUMO

Antigen delivery through an oral route requires overcoming multiple challenges, including gastrointestinal enzymes, mucus, and epithelial tight junctions. Although each barrier has a crucial role in determining the final efficiency of the oral vaccination, transcytosis of antigens through follicle-associated epithelium (FAE) represents a major challenge. Most of the research is focused on delivering an antigen to the M-cell for FAE transcytosis because M-cells can easily transport the antigen from the luminal site. However, the fact is that the M-cell population is less than 1% of the total gastrointestinal cells, and most of the oral vaccines have failed to show any effect in clinical trials. To challenge the current dogma of M-cell targeting, in this study, we designed a novel tandem peptide with a FAE-targeting peptide at the front position and a cell-penetrating peptide at the back position. The tandem peptide was attached to a smart delivery system, which overcomes the enzymatic barrier and the mucosal barrier. The result showed that the engineered system could target the FAE (enterocytes and M-cells) and successfully penetrate the enterocytes to reach the dendritic cells located at the subepithelium dome. There was successful maturation and activation of dendritic cells in vitro confirmed by a significant increase in maturation markers such as CD40, CD86, presentation marker MHC I, and proinflammatory cytokines (TNF-α, IL-6, and IL-10). The in vivo results showed a high production of CD4+ T-lymphocytes (helper T-cell) and a significantly higher production of CD8+ T-lymphocytes (killer T-cell). Finally, the production of mucosal immunity (IgA) in the trachea, intestine, and fecal extracts and systemic immunity (IgG, IgG1, and IgG2a) was successfully confirmed. To the best of our knowledge, this is the first study that designed a novel tandem peptide to target the FAE, which includes M-cells and enterocytes rather than M-cell targeting and showed that a significant induction of both the mucosal and systemic immune response was achieved compared to M-cell targeting.


Assuntos
Imunidade nas Mucosas/efeitos dos fármacos , Nanopartículas/administração & dosagem , Nanopartículas/química , Administração Oral , Animais , Antígenos/imunologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Citocinas/metabolismo , Feminino , Humanos , Concentração de Íons de Hidrogênio , Imunidade , Imunoglobulina A/metabolismo , Imunoglobulina G/metabolismo , Camundongos Endogâmicos C57BL , Nanopartículas/toxicidade , Ovalbumina/imunologia , Nódulos Linfáticos Agregados/imunologia , Baço/efeitos dos fármacos , Células Th1/metabolismo , Células Th2 , Vacinas/administração & dosagem , Vacinas/síntese química , Vacinas/química , Vacinas/farmacocinética
15.
Int J Psychiatry Clin Pract ; 15(2): 91-6, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22121856

RESUMO

OBJECTIVE: The purpose of this study was to determine the impact of symptoms of depression and anxiety on mortality in patients hospitalized for acute myocardial infarction (MI). METHODS: A total of 806 consecutive patients were screened within 15 days after MI and 24-month survival rate was ascertained. The Beck Depression Inventory and the State-Trait Anxiety Inventory were completed by patients hospitalized for MI. We tested the BDI × STAI interaction effect in addition to the BDI and STAI main effects. RESULTS: At 24 months' follow up cardiac mortality was assessed in 540 of 806 eligible patients (67% response rate); 531 of 806 for whom baseline data were collected (65.9%) were depressed and 556 (69.0%) were anxious after their MI. Fifty-five (10.2%) patients died during the 24-month follow-up. Neither state of anxiety nor depression scores at entry was different between patients who died from those who survived. CONCLUSIONS: Symptoms of depression and anxiety did not predict cardiac mortality after MI, but despite the negative results regarding the impact of depression on cardiac outcome, it should be stressed that this does not mean that physicians and cardiologists could ignore depression and anxiety.


Assuntos
Transtornos de Ansiedade/mortalidade , Ansiedade/mortalidade , Depressão/mortalidade , Transtorno Depressivo/mortalidade , Infarto do Miocárdio/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Ansiedade/complicações , Transtornos de Ansiedade/complicações , Depressão/complicações , Transtorno Depressivo/complicações , Feminino , Seguimentos , Humanos , Irã (Geográfico)/epidemiologia , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/complicações , Fatores de Risco , Taxa de Sobrevida
16.
Nanomedicine (Lond) ; 16(3): 237-258, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33501839

RESUMO

With significant advancements in research technologies, and an increasing global population, microfluidic and nanofluidic systems (such as point-of-care, lab-on-a-chip, organ-on-a-chip, etc) have started to revolutionize medicine. Devices that combine micron and nanotechnologies have increased sensitivity, precision and versatility for numerous medical applications. However, while there has been extensive research on microfluidic and nanofluidic systems, very few have experienced wide-spread commercialization which is puzzling and deserves our collective attention. For the above reasons, in this article, we review research advances that combine micro and nanotechnologies to create the next generation of nanomaterial-based microfluidic systems, the latest in their commercialization success and failure and highlight the value of these devices both in industry and in the laboratory.


Assuntos
Técnicas Analíticas Microfluídicas , Nanoestruturas , Dispositivos Lab-On-A-Chip , Microfluídica , Nanotecnologia , Sistemas Automatizados de Assistência Junto ao Leito
17.
J Mol Graph Model ; 106: 107899, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33857891

RESUMO

Polycrystalline carbon nanosheets are composed of several randomly rotated monocrystalline regions facing each other in grain boundaries-the cause of stress concentration-that affects the mechanics of 2D carbon nanostructures. They have been widely used in different fields, particularly in electronic devices. Herein, heterogeneous graphitic carbon nitride (C3N) was considered as typical of polycrystalline carbon nanosheets for modelling its fracture behavior. The number of grains with random configuration, temperature, and crack length were systematically changed to track the mode and the intensity of failure of model nanosheets. Molecular dynamics simulations predictions unraveled the interatomic interaction in the C-C and C-N bonds. An increase in the number of grain boundaries from 3 to 25 as well as the length of crack led to more than 70% fall in the Young's modulus of polycrystalline carbon platelets. Stress intensity factor decreased against temperature, but increased by crack length enlargement demonstrating higher fracture toughness of small cracks. This theoretical approach can be generalized to capture the unique fracture fingerprint of polycrystalline carbon structures of different types.


Assuntos
Simulação de Dinâmica Molecular , Nanoestruturas , Carbono , Módulo de Elasticidade , Estresse Mecânico
18.
J Control Release ; 329: 50-62, 2021 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-33259849

RESUMO

Near-infrared (NIR)-induced dye-based theranostic drug delivery carriers are used for critical image-guided chemo-photothermal cancer therapy. However, most carriers fail to deliver sufficient heat and fluorescence efficiently due to direct π-π stacking of the aromatic rings of the NIR dye and drug. In the work reported herein, we examined a self-assembled heptamethine cyanine dye dimer (CyD) with improved heat and fluorescence delivery that was developed by manipulating the unique structural and optical properties of the dimer. The H-aggregation of CyD in an aqueous solution generated a great amount of heat by transforming the energy of the excited electrons into non-radiative energy. Moreover, the disulfide bond of CyD assisted nanoparticles with a drug by minimizing the interaction between the NIR dye and drug, and also by releasing the drug in a redox environment. As a result, DOX encapsulated within CyD (CyD/DOX) showed strong heat generation and fluorescence imaging in tumor-bearing mice, allowing detection of the tumor site and inhibition of tumor growth by chemo-photothermal therapy. The multiplicity of features supplied by the newly developed CyD demonstrated the potential of CyD/DOX as an NIR dye-based theranostic drug-delivery carrier for effective chemo-photothermal cancer therapy.


Assuntos
Hipertermia Induzida , Nanopartículas , Neoplasias , Animais , Linhagem Celular Tumoral , Doxorrubicina , Portadores de Fármacos , Sistemas de Liberação de Medicamentos , Camundongos , Fototerapia , Medicina de Precisão , Nanomedicina Teranóstica
19.
Sci Rep ; 11(1): 18753, 2021 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-34548596

RESUMO

The use of carbon nanotubes as anticancer drug delivery cargo systems is a promising modality as they are able to perforate cellular membranes and transport the carried therapeutic molecules into the cellular components. Our work describes the encapsulation process of a common anticancer drug, Isatin (1H-indole-2,3-dione) as a guest molecule, in a capped single-walled carbon nanotube (SWCNT) host with chirality of (10,10). The encapsulation process was modelled, considering an aqueous solution, by a molecular dynamics (MD) simulation under a canonical NVT ensemble. The interactions between the atoms of Isatin were obtained from the DREIDING force filed. The storage capacity of the capped SWCNT host was evaluated to quantify its capacity to host multiple Isatin molecules. Our results show that the Isatin can be readily trapped inside the volume cavity of the capped SWCNT and it remained stable, as featured by a reduction in the van der Waals forces between Isatin guest and the SWCNT host (at approximately - 30 kcal mol-1) at the end of the MD simulation (15 ns). Moreover, the free energy of encapsulation was found to be - 34 kcal mol-1 suggesting that the Isatin insertion procedure into the SWCNT occurred spontaneously. As calculated, a capped SWCNT (10,10) with a length of 30 Å, was able to host eleven (11) molecules of Isatin, that all remained steadily encapsulated inside the SWCNT volume cavity, showing a potential for the use of carbon nanotubes as drug delivery cargo systems.


Assuntos
Antineoplásicos/administração & dosagem , Portadores de Fármacos , Isatina/administração & dosagem , Nanotubos de Carbono/química , Isatina/química , Simulação de Dinâmica Molecular
20.
Int J Nanomedicine ; 16: 4277-4288, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34194228

RESUMO

INTRODUCTION: Antimicrobial peptides are potential therapeutics as anti-bacteria, anti-viruses, anti-fungi, or anticancers. However, they suffer from a short half-life and drug resistance which limit their long-term clinical usage. METHODS: Herein, we captured the encapsulation of antimicrobial peptide HA-FD-13 into boron nitride nanotube (BNNT) (20,20) and its release due to subsequent insertion of BNNT (14,14) with molecular dynamics simulation. RESULTS: The peptide-BNNT (20,20) van der Waals (vdW) interaction energy decreased to -270 kcal·mol-1 at the end of the simulation (15 ns). However, during the period of 0.2-1.8 ns, when half of the peptide was inside the nanotube, the encapsulation was paused due to an energy barrier in the vicinity of BNNT and subsequently the external intervention, such that the self-adjustment of the peptide allowed full insertion. The free energy of the encapsulation process was -200.12 kcal·mol-1, suggesting that the insertion procedure occurred spontaneously. DISCUSSION: Once the BNNT (14,14) entered into the BNNT (20,20), the peptide was completely released after 83.8 ps. This revealed that the vdW interaction between the BNNT (14,14) and BNNT (20,20) was stronger than between BNNT (20,20) and the peptide; therefore, the BNNT (14,14) could act as a piston pushing the peptide outside the BNNT (20,20). Moreover, the sudden drop in the vdW energy between nanotubes to the value of the -1300 Kcal·mol-1 confirmed the self-insertion of the BNNT (14,14) into the BNNT (20,20) and correspondingly the release of the peptide.


Assuntos
Compostos de Boro/química , Nanotubos/química , Proteínas Citotóxicas Formadoras de Poros/química , Proteínas Citotóxicas Formadoras de Poros/farmacocinética , Simulação de Dinâmica Molecular , Conformação Proteica em alfa-Hélice
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