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1.
Pharmaceuticals (Basel) ; 16(2)2023 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-37259380

RESUMO

P2Y12 inhibitor monotherapy is a feasible alternative treatment for patients after percutaneous coronary intervention (PCI) in the modern era. Clinical trials have shown that it could lower the risk of bleeding complications without increased ischemic events as compared to standard dual antiplatelet therapy (DAPT). However, the efficacy and safety of this novel approach among patients with acute coronary syndrome (ACS) are controversial because they have a much higher risk for recurrent ischemic events. The purpose of this study is to evaluate the efficacy and safety of this novel approach among patients with ACS. We conducted a meta-analysis of randomized controlled trials that compared P2Y12 inhibitor monotherapy with 12-month DAPT in ACS patients who underwent PCI with stent implantation. PubMed, Embase, the Cochrane library database, ClinicalTrials.gov, and other three websites were searched for data from the earliest report to July 2022. The primary efficacy outcome was major adverse cardiovascular and cerebrovascular events (MACCE), a composite of all-cause mortality, myocardial infarction, stent thrombosis, or stroke. The primary safety outcome was major or minor bleeding events. The secondary endpoint was net adverse clinical events (NACE), defined as a composite of major bleeding and adverse cardiac and cerebrovascular events. Five randomized controlled trials with a total of 21,034 patients were included in our meta-analysis. The quantitative analysis showed a significant reduction in major or minor bleeding events in patients treated with P2Y12 inhibitor monotherapy as compared with standard DAPT(OR: 0.59, 95% CI: 0.46-0.75, p < 0.0001) without increasing the risk of MACCE (OR: 0.98, 95% CI: 0.86-1.13, p = 0.82). The NACE was favorable in the patients treated with P2Y12 inhibitor monotherapy (OR: 0.82, 95% CI: 0.73-0.93, p = 0.002). Of note, the overall clinical benefit of P2Y12 inhibitor monotherapy was quite different between ticagrelor and clopidogrel. The incidence of NACE was significantly lower in ticagrelor monotherapy as compared with DAPT (OR: 0.79, 95% CI: 0.68-0.91), but not in clopidogrel monotherapy (OR: 1.14, 95% CI: 0.79-1.63). Both clopidogrel and ticagrelor monotherapy showed a similar reduction in bleeding complications (OR: 0.46, 95% CI: 0.22-0.94; OR: 0.60, 95% CI: 0.44-0.83, respectively). Although statistically insignificant, the incidence of MACCE was numerically higher in clopidogrel monotherapy as compared with standard DAPT (OR: 1.50, 95% CI: 0.99-2.28, p = 0.06). Based on these findings, P2Y12 inhibitor monotherapy with ticagrelor would be a better choice of medical treatment for ACS patients after PCI with stent implantation in the current era.

2.
Medicine (Baltimore) ; 102(12): e33413, 2023 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-36961132

RESUMO

RATIONALE: An arteriovenous malformation (AVM) is an abnormal tangle of blood vessels that connects the arteries and the veins. Because normal capillary bed is partially or completely absented in the AVM, the blood passes quickly from the arteries to the veins, which disrupts normal blood flow and oxygen supply to the surrounding tissues. This is called "steal phenomenon," and in the inferior mesenteric artery (IMA) territory, this may lead to abdominal pain, gastrointestinal bleeding, portal hypertension, and even ischemic colitis. PATIENT CONCERNS: A 67-year-old man presented to our emergency department because of left side abdominal pain. DIAGNOSES: The abdominal computed tomography with contrast enhancement revealed a cluster of abnormal vascular lesions abutting the IMA with early opacification of the left colonic marginal vein. In addition, poor enhancement of segmental colonic wall was found from proximal descending colon to middle rectum. The diagnosis of AVM of the IMA and ischemic colitis was made. INTERVENTIONS: The patient underwent left hemicolectomy as well as the AVM resection. OUTCOMES: He was discharged uneventfully after the surgery without complications. LESSONS: IMA AVM carries the risk of ischemic colitis. computed tomography scan is helpful not only to the diagnosis of AVMs but also to exclude other lesions as well. Treatment options include endovascular embolization, surgical intervention, and a combination of both. Due to the complexity of this disease, treatment requires a case-specific multidisciplinary approach and a coordination of medical, radiological, and surgical staffs.


Assuntos
Malformações Arteriovenosas , Colite Isquêmica , Masculino , Humanos , Idoso , Colite Isquêmica/diagnóstico , Colite Isquêmica/etiologia , Colite Isquêmica/cirurgia , Artéria Mesentérica Inferior/diagnóstico por imagem , Artéria Mesentérica Inferior/cirurgia , Malformações Arteriovenosas/complicações , Malformações Arteriovenosas/diagnóstico por imagem , Malformações Arteriovenosas/cirurgia , Dor Abdominal
3.
Medicine (Baltimore) ; 102(5): e32838, 2023 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-36749242

RESUMO

INTRODUCTION: Acute abdominal pain caused by torsion of the pedunculated subserosal leiomyoma is rare. Miss diagnosis can lead to ischemia, necrosis, and subsequent peritonitis which may cause significant morbidity. Torsion of the leiomyoma should be recognized as a surgical emergency and once suspected, early surgical intervention should be considered. PATIENT CONCERNS: A 28-year-old woman with a medical history of uterine leiomyoma presented to our emergency department because of acute onset right lower abdominal pain. DIAGNOSES: The computed tomography was performed which demonstrated multiple leiomyomas of variable sizes and a subserosal leiomyoma located at right lower abdomen with poor contrast enhancement. INTERVENTIONS: The gynecologist was consulted, and myomectomy was performed. The intraoperative finding showed a pedunculated subserosal leiomyoma with torsion. OUTCOMES: She underwent myomectomy for the twisted pedunculated subserosal leiomyoma as well as other leiomyomas and was discharged with a favorable outcome. CONCLUSIONS: Torsion of the leiomyoma is a surgical emergency as delayed in treatment may lead to marked morbidity. Once suspected, the gynecologist must be consulted, and surgical intervention should be considered.


Assuntos
Abdome Agudo , Leiomioma , Miomectomia Uterina , Neoplasias Uterinas , Feminino , Humanos , Adulto , Leiomioma/cirurgia , Neoplasias Uterinas/cirurgia , Dor Abdominal , Miomectomia Uterina/métodos , Abdome Agudo/etiologia
4.
Medicine (Baltimore) ; 101(47): e31483, 2022 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-36451393

RESUMO

INTRODUCTION: Phlegmasia cerulea dolens (PCD) is an uncommon condition of acute deep vein thrombosis, characterized by marked swelling of the affected limb with pain and cyanosis. High mortality and morbidity rates have been reported. Early diagnosis, quick and effective treatment are crucial for preventing potential limb loss or even death. PATIENT CONCERNS: A 39-year-old woman presented to our emergency department with painful swelling and cyanotic discoloration of the left lower limb for 2 days. DIAGNOSES: Computed tomography revealed thrombosis in the left common iliac vein and inferior vena cava. Angiography demonstrated extensive venous occlusion from the lower inferior vena cava to the left popliteal vein. The diagnosis of PCD was made. INTERVENTIONS: Systemic anticoagulation with intravenous unfractionated heparin was initiated immediately. Mechanical thrombectomy with Angiojet and angioplasty were performed, and catheter-directed thrombolysis (CDT) was administered subsequently. OUTCOMES: Follow-up angiography revealed regression of the thrombosis and the opacification of the deep vein was restored. The patient was discharged from the hospital uneventfully. CONCLUSIONS: PCD is a rare but potentially limb and life-threatening condition that requires immediate recognition. Treatment should be in a timely manner. Anticoagulation alone may be inadequate and more aggressive management such as CDT and thrombectomy should be considered.


Assuntos
Heparina , Trombose Venosa , Feminino , Humanos , Adulto , Heparina/uso terapêutico , Trombectomia , Trombose Venosa/diagnóstico por imagem , Trombose Venosa/tratamento farmacológico , Catéteres , Extremidade Inferior , Cianose , Anticoagulantes , Terapia Trombolítica
5.
Regul Toxicol Pharmacol ; 124: 104970, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34087384

RESUMO

BACKGROUND: Statin is biologically plausible in cataract development, but inconclusive associations between statin and cataract are presented in human studies. Given most early onset cataract (EOC) occurs in regions with high cholesterol composition, we therefore aimed to assess the association between statin and EOC. METHODS: A population based case-control study was performed using the Taiwan National Health Insurance Research Database (NHIRD). The case involved patients aged 20-55 years with EOC. Controls were 1:1 matched by age, gender, year of index date, and propensity score estimated from comorbidities and comedications. Statin exposure, including intensity, properties and cumulative exposure one year before the index date were tracked. The odds ratios (ORs) of EOC associated with statin were estimated by conditional logistic regression. RESULTS: A total of 4213 cases and 4213 controls were included. Statins were associated with EOC (OR = 3.257, 95% CI 2.519-4.211). The ORs of cataract was positively associated with cumulative exposure. Subgroup analysis indicated that the ORs of cataract were significant both in lipophilic (OR = 3.485, 95% CI 2.606-4.659) and hydrophilic (OR = 3.241, 95% CI 1.975-5.321) statin users. CONCLUSIONS: Statins were associated with an increased risk of cataract in young populations.


Assuntos
Catarata/epidemiologia , Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , Adulto , Idade de Início , Estudos de Casos e Controles , Catarata/induzido quimicamente , Bases de Dados Factuais/estatística & dados numéricos , Feminino , Humanos , Interações Hidrofóbicas e Hidrofílicas , Inibidores de Hidroximetilglutaril-CoA Redutases/química , Masculino , Pessoa de Meia-Idade , Razão de Chances , Prevalência , Medição de Risco/estatística & dados numéricos , Fatores de Risco , Taiwan/epidemiologia , Adulto Jovem
6.
Hypertens Res ; 44(7): 850-857, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33707757

RESUMO

Low ankle-brachial index (ABI) and high ABI difference (ABID) are each associated with poor prognosis. No study has assessed the ability of the combination of low ABI and high ABID to predict survival. We created an ABI score by assigning 1 point for ABI < 0.9 and 1 point for ABID ≥ 0.17 and examine the ability of this ABI score to predict mortality. We included 941 patients scheduled for echocardiographic examination. The ABI was measured using an ABI-form device. ABID was calculated as |right ABI-left ABI|. Among the 941 subjects, the prevalence of ABI < 0.9 and ABID ≥ 0.17 was 6.1% and 6.8%, respectively. Median follow-up to mortality was 93 months. There were 87 cardiovascular and 228 overall deaths. All ABI-related parameters, including ABI, ABID, ABI < 0.9, ABID ≥ 0.17, and ABI score, were significantly associated with overall and cardiovascular mortality in the multivariable analysis (P ≤ 0.009). Further, in the direct comparison of multivariable models, the basic model + ABI score was the best at predicting overall and cardiovascular mortality among the five ABI-related multivariable models (P ≤ 0.049). Hence, the ABI score, a combination of ABI < 0.9 and ABID ≥ 0.17, should be calculated for better mortality prediction.


Assuntos
Índice Tornozelo-Braço , Doenças Cardiovasculares , Doenças Cardiovasculares/mortalidade , Humanos , Valor Preditivo dos Testes
7.
Am J Med Sci ; 361(4): 479-484, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33637306

RESUMO

BACKGROUND: Pulse wave velocity (PWV) is an excellent index of arterial stiffness and can be used to predict long-term cardiovascular (CV) outcome. In recent years, estimated PWV (ePWV), calculated by equations using age and mean blood pressure, was also reported to be a significant predictor of CV outcomes. However, there was no literature discussing about usefulness of ePWV in patients of acute myocardial infarction (AMI) for prediction of long-term CV and overall mortality. Therefore, we conducted this study for further evaluation. METHODS: A total of 187 patients with AMI admitted to cardiac care unit were enrolled. ePWV were calculated by the equations for each patient. RESULTS: The median follow-up to mortality was 73 months (25th-75th percentile: 8-174 months). There were 35 and 125 patients documented as CV and overall mortality, respectively. Under univariable analysis, ePWV could independently predict long-term CV and overall mortality. However, after multivariable analysis, ePWV could only predict long-term CV mortality in AMI patients. CONCLUSIONS: To the best of our knowledge, our study was the first to evaluate the usefulness of ePWV in AMI patients for prediction of long-term CV and overall mortality. Our study showed ePWV was not only easy to calculate by formula, but also an independent predictor for long-term CV mortality in univariable and multivariable analyses. Therefore, ePWV was a simple and useful tool to measure arterial stiffness and to predict CV mortality outcome in AMI patients without the necessity for equipment to measure PWV.


Assuntos
Infarto do Miocárdio/mortalidade , Análise de Onda de Pulso/estatística & dados numéricos , Rigidez Vascular , Doença Aguda/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Taiwan/epidemiologia
8.
PLoS One ; 16(1): e0245860, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33513173

RESUMO

Left ventricular systolic function is a good indicator of cardiac function and a powerful predictor of adverse cardiovascular (CV) outcomes. High ratio of pre-ejection period (PEP) to ejection time (ET) is associated with reduced left ventricular systolic function. Brachial PEP (bPEP) and brachial ET (bET) can be automatically calculated from an ankle-brachial index (ABI)-form device and bPEP/bET was recently reported to be a new and useful parameter of cardiac performance. However, there were no studies evaluating the utility of bPEP/bET for prediction of CV and overall mortality in patients with acute myocardial infarction (AMI). We included 139 cases of AMI admitted to our cardiac care unit consecutively. ABI, bPEP, and bET were obtained from the ABI-form device within the 24 hours of admission. There were 87 overall and 22 CV mortality and the median follow-up to mortality event was 98 months. After multivariable analysis, high bPEP/bET was not only associated with increased long-term CV mortality (hazard ratio (HR) = 1.046; 95% confidence interval (CI): 1.005-1.088; P = 0.029), but also associated with long-term overall mortality (HR = 1.023; 95% CI: 1.001-1.045; P = 0.042). In addition, age was also a significant predictor for CV and overall mortality after the multivariable analysis. In conclusion, bPEP/bET was shown to be a significant predictor for CV and overall mortality in AMI patients after multivariable analysis. Therefore, by means of this novel parameter, we could easily find out the high-risk AMI patients with increased CV and overall mortality.


Assuntos
Índice Tornozelo-Braço/métodos , Infarto do Miocárdio/diagnóstico , Idoso , Índice Tornozelo-Braço/normas , Índice Tornozelo-Braço/estatística & dados numéricos , Artéria Braquial/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mortalidade/tendências , Análise Multivariada , Infarto do Miocárdio/mortalidade , Valor Preditivo dos Testes , Sístole
9.
J Clin Hypertens (Greenwich) ; 22(11): 2044-2050, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33086427

RESUMO

A low ankle-brachial index (ABI) calculated using systolic blood pressure (SBP) (ABIsbp) is associated with poor cardiovascular outcome in patients with acute myocardial infarction (AMI). ABI is always calculated using SBP clinically. However, there was no study investigating ABI calculated using mean artery pressure (MAP)(ABImap) and diastolic blood pressure (DBP)(ABIdbp) for mortality prediction in AMI patients. Therefore, our study was aimed to investigate the issue. 199 AMI patients were enrolled. Different ABIs were measured by an ABI-form device. The median follow-up to mortality was 64 months. There were 40 cardiovascular and 137 all-cause mortality. The best cutoff values of ABImbp and ABIdbp for mortality prediction were 0.91 and 0.78, respectively. After multivariate analysis, only ABIdbp and ABIdbp < 0.78 could predict cardiovascular mortality (P ≤ .047). However, all of six ABI parameters, including ABIsbp, ABImap, ABIdbp, ABIsbp < 0.90, ABImap < 0.91, and ABIdbp < 0.78, could predict all-cause mortality (P ≤ .048). In a direct comparison of six ABI models for prediction of all-cause mortality, basic model + ABIdbp <0.78 had the highest predictive value (P ≤ .025). In conclusion, only ABIdbp and ABIdbp < 0.78 could predict cardiovascular and all-cause mortality after multivariate analysis in our study. Furthermore, when adding into a basic model, ABIdbp < 0.78 had the highest additively predictive value for all-cause mortality in the six ABI parameters. Hence, calculation of ABI using DBP except SBP might provide an extra benefit in prediction of cardiovascular and all-cause mortality in AMI patients.


Assuntos
Hipertensão , Infarto do Miocárdio , Índice Tornozelo-Braço , Pressão Sanguínea , Humanos , Infarto do Miocárdio/diagnóstico , Valor Preditivo dos Testes , Fatores de Risco
10.
J Clin Med ; 9(4)2020 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-32218225

RESUMO

Background: Acute myocardial infarction (AMI) is one of the leading causes of death in the world. How to simply predict mortality for AMI patients is important because the appropriate treatment should be done for the patients with higher risk. Recently, a novel parameter of upstroke time per cardiac cycle (UTCC) in lower extremities was reported to be a good predictor of peripheral artery disease and mortality in elderly. However, there was no literature discussing the usefulness of UTCC for prediction of cardiovascular (CV) and overall mortality in AMI patients. Methods: 184 AMI patients admitted to the cardiac care unit were enrolled. Ankle-brachial index (ABI) and UTCC were measured by an ABI-form device in the same day of admission. Results: The median follow-up to mortality was 71 months. There were 36 CV and 124 overall mortality. Higher UTCC was associated with increased CV and overall mortality after multivariable analysis (P = 0.033 and P < 0.001, respectively). However, ABI was only associated with CV mortality and overall mortality in the univariable analysis but became insignificant after the multivariable analysis. In addition, after adding UTCC into a basic model including important clinical parameters, left ventricular ejection fraction, Charlson comorbidity index, and ABI, we found the basic model + UTCC had a better predictive value for overall mortality than the basic model itself (P < 0.001). Conclusions: Our study is the first one to evaluate the usefulness of UTCC in AMI patients for prediction of long-term mortality. Our study showed UTCC was an independent predictor of long-term CV and overall mortality and had an additive predictive value for overall mortality beyond conventional parameters. Therefore, screening AMI patients by UTCC might help physicians to identify the high-risk group with increased mortality.

11.
Medicine (Baltimore) ; 99(3): e18598, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32011439

RESUMO

A large interarm and interleg systolic blood pressure (SBP) difference and ankle-brachial index (ABI) <0.9 were associated with peripheral artery disease and left ventricular hypertrophy. These 3 parameters were derived from 4-limb SBP data. However, there is no study to assess clinical significance of SBP heterogeneity in 4 limbs. The aim of this study was to evaluate the association of 4-limb SBP standard deviation (SD) with peripheral vascular parameters and echocardiographic data in patients with or without clinical findings of peripheral artery disease.A total of 1240 patients were included, of whom 1020 had no clinical evidence of overt peripheral artery disease. The 4-limb blood pressures, brachial-ankle pulse wave velocity, and ABI were measured simultaneously by an ABI-form device.In the multivariable linear regression analysis, increased left ventricular mass index (LVMI), ABI < 0.9, interarm SBP difference >10 mm Hg, and interleg SBP difference >15 mm Hg (P ≤ .030) were associated with increased 4-limb SBP SD. Additionally, a subgroup multivariable linear regression analysis in 1020 patients without ABI < 0.9, interarm SBP difference >10 mm Hg, and interleg SBP difference >15 mm Hg found 4-limb SBP SD still had a positive correlation with LVMI (P < .001).In addition to significant association with ABI < 0.9, interarm SBP difference >10 mm Hg, and interleg SBP difference >15 mm Hg, 4-limb SBP SD was positively correlated with LVMI in the multivariable linear regression analysis in all study patients. Furthermore, in the subgroup of patients without clinical evidence of peripheral artery disease, 4-limb SBP SD still had a positive correlation with LVMI. Hence, assessment of 4-limb SBP heterogeneity is useful in identification of high-risk group of peripheral artery disease and/or increased LVMI, irrespective of the presence of overt peripheral artery disease.


Assuntos
Pressão Sanguínea/fisiologia , Ecocardiografia/métodos , Extremidades/fisiopatologia , Hipertrofia Ventricular Esquerda/fisiopatologia , Doença Arterial Periférica/fisiopatologia , Índice Tornozelo-Braço , Feminino , Humanos , Modelos Lineares , Masculino , Doença Arterial Periférica/diagnóstico , Análise de Onda de Pulso
12.
JACC Case Rep ; 1(5): 792-795, 2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-34316933

RESUMO

Stumpless chronic total occlusion is associated with a higher failure rate of recanalization. Intravascular ultrasound (IVUS) is useful for identifying the entry point; however, 8-F guide catheters are necessary for real-time IVUS-guided wiring. This case reports the novel use of the "ping-pong" guide catheter technique to facilitate real-time IVUS-guided wiring for a stumpless chronic total occlusion. (Level of Difficulty: Advanced.).

13.
Acta Cardiol Sin ; 32(6): 667-675, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27899853

RESUMO

BACKGROUND: Significantly higher cytotoxic and thrombogenic human electronegative low-density lipoprotein (LDL), or L5, has been found in patients with stable coronary artery disease and acute coronary syndrome. We hypothesized that the statin-benefit groups (SBGs) defined by the new cholesterol guideline were of higher electronegative L5. METHODS: In total, 62 hyperlipidemia patients (mean age 59.4 ± 10.5, M/F 40/22) were retrospectively divided into SBGs (n = 44) and N-SBGs (n = 18). The levels of complete basic lipid panel, biochemical profile and electronegative L5 of each individual were obtained before and after rosuvastatin 10 mg/day for 3 months. RESULTS: After 3 months' statin therapy, significant reduction of total cholesterol, LDL-C and triglyceride were demonstrated (all p-values < 0.05), with 38.4% LDL-C reduction. The percentage of L5 was significantly reduced by 40.9% (from 4.4% to 2.6%) after statin therapy (p = 0.001). Regarding absolute L5 concentration, derived from L5% multiplied by LDL-C, there was approximate 63.8% reduction (from 6.3 mg/dL to 2.3 mg/dL) of absolute L5 (p < 0.001) after statin treatment. Notably, while plasma LDL-C levels were similar between SBGs and N-SBGs (152.8 ± 48.6 vs. 146.9 ± 35.0 mg/dL), the SBGs had significantly elevated L5% (5.2 ± 7.4% vs. 2.6 ± 1.9%, p = 0.031) and higher absolute L5 concentration (7.4 ± 10.4 vs. 3.7 ± 3.1 mg/dL, p = 0.036). Linear regression showed the significantly positive correlation between the plasma L5 concentration and the 10-year cardiovascular risk by pooled cohort equation (r = 0.297, p < 0.05). CONCLUSIONS: The four SBGs defined by the 2013 ACC/AHA new cholesterol guideline tend to have increased atherogenic electronegative L5. Statin therapy can effectively reduce the electronegative L5 of these four major SBGs.

14.
Acta Cardiol Sin ; 30(6): 578-81, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27122838

RESUMO

UNLABELLED: Although recurrent ST-segment elevation myocardial infarction (STEMI) in the same coronary artery due to acute stent thrombosis has been reported in the literature, there have been no reported cases discussing consecutive STEMI recurring in different coronary arteries in the same patient in one day. Herein, we report an elderly male patient initially suffering from STEMI over the inferior wall who subsequently had another episode of STEMI over the anterior wall within several hours. Despite primary percutaneous coronary intervention being performed over both the right coronary artery and the left anterior descending artery, the patient eventually expired notwithstanding intensive care. This case should caution physicians that consecutive STEMI in different coronary arteries is an extremely rare but still possible medical phenomenon, and could lead to catastrophic clinical outcome. KEY WORDS: Myocardial infarction; Primary percutaneous coronary intervention; Recurrent ST-elevation.

15.
ACS Nano ; 5(10): 7788-95, 2011 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-21910421

RESUMO

In this study, graphene oxide nanoribbons (GONRs) were synthesized from the facile unzipping of multiwalled carbon nanotubes (MWCNTs) with the help of microwave energy. A core-shell MWCNT/GONR-modified glassy carbon (MWCNT/GONR/GC) electrode was used to electrochemically detect ascorbic acid (AA), dopamine (DA), and uric acid (UA). In cyclic voltammograms, the MWCNT/GONR/GC electrode was found to outperform the MWCNT- and graphene-modified GC electrodes in terms of peak current. For the simultaneous sensing of three analytes, well-separated voltammetric peaks were obtained using a MWCNT/GONR/GC electrode in differential pulse voltammetry measurements. The corresponding peak separations were 229.9 mV (AA to DA), 126.7 mV (DA to UA), and 356.6 mV (AA to UA). This excellent electrochemical performance can be attributed to the unique electronic structure of MWCNTs/GONRs: a high density of unoccupied electronic states above the Fermi level and enriched oxygen-based functionality at the edge of the graphene-like structures, as revealed by X-ray absorption near-edge structure spectroscopy, obtained using scanning transmission X-ray microscopy.


Assuntos
Ácido Ascórbico/análise , Técnicas de Química Sintética/métodos , Dopamina/análise , Micro-Ondas , Nanoestruturas/química , Ácido Úrico/análise , Ácido Ascórbico/química , Dopamina/química , Eletroquímica , Eletrodos , Vidro/química , Grafite/química , Nanotubos de Carbono/química , Ácido Úrico/química
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