RESUMO
Single-drop microextraction (SDME) was coupled with surface-enhanced Raman scattering (SERS) to provide sample extraction and pre-concentration for detection of analyte at low concentrations. A gold nanohole array substrate (AuNHAS), fabricated by interference lithography, was used as SERS substrate and para-mercaptobenzoic acid (p-MBA) was tested as a probe molecule, in the concentration range 10-8-10-4 mol L-1. With this approach, a limit of 10-7 mol L-1 was clearly detected. To improve the detection to lower p-MBA concentration, as 10-8 mol L-1, the SDME technique was applied. The p-MBA Raman signature was detected in two performed extractions and its new concentration was determined to be ~4.6 × 10-5 mol L-1. This work showed that coupling SDME with SERS allowed a rapid (5 min) and efficient pre-concentration (from 10-8 mol L-1 to 10-5 mol L-1), detection, and quantification of the analyte of interest, proving to be an interesting analytical tool for SERS applications.
RESUMO
BACKGROUND: Chagas' heart disease is an important public health problem in South America. Several aspects of the pathogenesis are not fully understood, especially in its subclinical phases. On pathology Chagas' heart disease is characterized by chronic myocardial inflammation and extensive myocardial fibrosis. The latter has also been demonstrated by late gadolinium enhancement (LGE) by cardiovascular magnetic resonance (CMR). In three clinical phases of this disease, we sought to investigate the presence of LGE, myocardial increase in signal intensity in T2-weighted images (T2W) and in T1-weighted myocardial early gadolinium enhancement (MEGE), previously described CMR surrogates for myocardial fibrosis, myocardial edema and hyperemia, respectively. METHODS: Fifty-four patients were analyzed. Sixteen patients with the indeterminate phase (IND), seventeen patients with the cardiac phase with no left ventricular systolic dysfunction (CPND), and twenty-one patients with the cardiac phase with left ventricular systolic dysfunction (CPD). All patients underwent 1.5 T CMR scan including LGE, T2W and MEGE image sequences to evaluate myocardial abnormalities. RESULTS: Late gadolinium enhancement was present in 72.2 % of all patients, in 12.5 % of IND, 94.1 % of the CPND and 100 % of the CPD patients (p < 0.0001). Myocardial increase in signal intensity in T2-weighted images (T2W) was present in 77.8 % of all patients, in 31.3 % of the IND, 94.1 % of the CPND and 100 % of the CPD patients (p < 0.0001). T1-weighted myocardial early gadolinium enhancement (MEGE) was present in 73.8 % of all patients, in 25.0 % of the IND, 92.3 % of the CPND and 94.1 % of the CPD (p < 0.0001). A good correlation between LGE and T2W was observed (r = 0.72, and p < 0.001). CONCLUSIONS: Increase in T2-weighted (T2W) myocardial signal intensity and T1-weighted myocardial early gadolinium enhancement (MEGE) can be detected by CMR in patients throughout all phases of Chagas' heart disease, including its subclinical presentation (IND). Moreover, those findings were parallel to myocardial fibrosis (LGE) in extent and location and also correlated with the degree of Chagas' heart disease clinical severity. These findings contribute to further the knowledge on pathophysiology of Chagas' heart disease, and might have therapeutic and prognostic usefulness in the future.
Assuntos
Cardiomiopatia Chagásica/patologia , Edema Cardíaco/patologia , Imageamento por Ressonância Magnética , Miocárdio/patologia , Disfunção Ventricular Esquerda/patologia , Adulto , Idoso , Cardiomiopatia Chagásica/parasitologia , Cardiomiopatia Chagásica/fisiopatologia , Meios de Contraste , Estudos Transversais , Edema Cardíaco/parasitologia , Edema Cardíaco/fisiopatologia , Feminino , Fibrose , Compostos Heterocíclicos , Humanos , Masculino , Pessoa de Meia-Idade , Compostos Organometálicos , Valor Preditivo dos Testes , Índice de Gravidade de Doença , Sístole , Disfunção Ventricular Esquerda/parasitologia , Disfunção Ventricular Esquerda/fisiopatologia , Função Ventricular EsquerdaRESUMO
BACKGROUND: Increasing age and cholesterol levels, male gender, and family history of early coronary heart disease (CHD) are associated with early onset of CHD in familial hypercholesterolemia (FH). OBJECTIVE: Assess subclinical atherosclerosis by computed tomography coronary angiography (CTCA) and its association with clinical and laboratorial parameters in asymptomatic FH subjects. METHODS: 102 FH subjects (36% male, 45 ± 13 years, LDL-c 280 ± 54 mg/dL) and 35 controls (40% male, 46 ± 12 years, LDL-c 103 ± 18 mg/dL) were submitted to CTCA. Plaques were divided into calcified, mixed and non-calcified; luminal stenosis was characterized as >50% obstruction. RESULTS: FH had a greater atherosclerotic burden represented by higher number of patients with: plaques (48% vs. 14%, p=0.0005), stenosis (19% vs. 3%, p=0.015), segments with plaques (2.05 ± 2.85 vs.0.43 ± 1.33, p=0.0016) and calcium scores (55 ± 129 vs. 38 ± 140, p=0.0028). After multivariate analysis, determinants of plaque presence were increasing age (OR=2.06, for age change of 10 years, CI95%: 1.38-3.07, p<0.001) and total cholesterol (OR=1.86, for cholesterol change by 1 standard deviation, CI95%: 1.09-3.15, p=0.027). Coronary calcium score was associated with the presence of stenosis (OR=1.54; CI95%: 1.27-1.86, p<0.001, for doubling the calcium score). Male gender was directly associated with the presence of non-calcified plaques (OR: 15.45, CI95% 1.72-138.23, p=0.014) and inversely with calcified plaques (OR=0.21, CI95%: 0.05-0.84, p=0.027). Family history of early CHD was associated with the presence of mixed plaques (OR=4.90, CI95%: 1.32-18.21, p=0.018). CONCLUSIONS: Patients with FH had an increased burden of coronary atherosclerosis by CTCA. The burden of atherosclerosis and individual plaque subtypes differed with the presence of other associated risk factors, with age and cholesterol being most important. A coronary calcium score of zero ruled out obstructive disease in this higher risk population.
Assuntos
Calcinose/complicações , LDL-Colesterol/sangue , Doença da Artéria Coronariana/diagnóstico por imagem , Hiperlipoproteinemia Tipo II/complicações , Adulto , Fatores Etários , Calcinose/diagnóstico por imagem , Angiografia Coronária , Doença da Artéria Coronariana/complicações , Feminino , Humanos , Hiperlipoproteinemia Tipo II/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Tomografia Computadorizada por Raios XRESUMO
Takayasu arteritis is a form of large vessel vasculitis with a possible autoimmune origin that may cause stenosis of the aorta and its major branches. Six types of Takayasu arteritis are recognized; the type depends on whether the ascending aorta, descending thoracic aorta, abdominal aorta, aortic cervicobrachial branches, or renal arteries are affected. The coronary and pulmonary arteries are also sometimes involved. Clinical features of the disease include diminished or absent pulses, claudication, hypertension, and mesenteric angina. Conventional angiography has been the standard imaging tool for diagnosis and evaluation of Takayasu arteritis, although it demonstrates only the lumen of the vessel. Less invasive cross-sectional methods such as computed tomographic angiography and, more recently, three-dimensional magnetic resonance (MR) angiography can effectively demonstrate thickening of the vessel wall, which may be the earliest manifestation of the disease, occurring before stenosis and dilatation. MR imaging in particular allows better soft-tissue differentiation and can show other signs of inflammation, including mural edema and increased mural vascularity. Other advantages of MR imaging are the lack of iodinated contrast material or ionizing radiation.