A simple and sensitive approach for the electrochemical determination of amaranth by a Pd/GO nanomaterial-modified screen-printed electrode

It is essential to develop easy-to-use sensors towards a better monitoring of food additives so that human health can be positively influenced. A type of critical food additive that is widely used in making soft drinks and diverse foodstuff is called amaranth. This study aimed at presenting a novel Pd/GO nanomaterial-modified screen-printed electrode (Pd/GO/SPE), which is responsible for providing a sensing interface during the process of specifying the electrochemical features of amaranth. The morphology and structure of the Pd/GO nanomaterial was investigated by Fourier-transform infrared spectroscopy, thermal gravimetric analysis, X-ray photoelectron spectroscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, scanning transmission electron microscopy, and high-resolution transmission electron microscopy. When the optimized conditions was adjusted, Pd/GO/SPE proved to be a capable sensor for conducting a very sensitive sensing towards the amaranth under a common working situation of 575 mV. In this regard, it was embarked on measuring some of the sensor features, including its sensitivity, linear dynamic range, and detection limit for amaranth with the values of 0.0948 μA μM⁻¹, 0.08 μM–360.0 μM and 30.0 nM were obtained, respectively.

It is essential to develop easy-to-use sensors towards a better monitoring of food additives so that human health can be positively influenced.     

Partial atrioventricular canal defect in elderly patients (aged 60 years or older)

Partial atrioventricular canal defect in elderly patients (aged 60 years or older) is extremely rare, and surgical results in this select group have not been reported. This report describes in detail the clinical profile of six such patients and the surgical results in four of the six. There was no operative mortality. This experience, albeit based on small numbers, suggests that operation can be performed at low risk with gratifying symptomatic improvement and that surgical repair in symptomatic elderly patients with partial atrioventricular canal detect can be justified.     

Two-dimensional echocardiographic assessment of dextrocardia: A segmental approach

Two-dimensional echocardiography was used in the prospective evaluation of 40 patients with the clinical diagnosis of dextrocardia. A segmental analysis of the situs, connections, ventricular anatomy, and chamber positions was utilized for a complete diagnostic assessment. An adequate examination was possible in 33 of these patients; the findings were confirmed by cardiac catheterization and angiography in 31 patients and at operation in 26.

Use of the location of the liver and the drainage of the hepatic veins and inferior vena cava allowed atrial visceral situs to be defined in 33 patients (solitus 21, inversus 9, and ambiguous 3). Pulmonary venous connections were correctly identified in 27. In 33 patients, atrioventricular (AV) and ventriculoarterial connections and ventricular anatomy were correctly predicted. Twenty patients had 2 separate well-developed ventricles. Ventriculoarterial connections were determined correctly in all 20 patients: concordant in 5, discordant in 6, double-outlet right ventricle in 5, and single-outlet right ventricle (pulmonary atresia) in 4. In 16 patients a ventricular septal defect was correctly identified. In the remainder the ventricular septum was intact.

Thirteen patients had univentricular heart: 8 had 2 AV valves (double-inlet ventricle), 3 had common AV inlet, and 2 had atresia of 1 AV connection.

Two-dimensional echocardiography allowed the accurate assessment of complex congenital heart defects associated with dextrocardia. Utilizing a segmental approach, one can correctly predict atrial-visceral situs, ventricular morphology and situs, and AV and ventriculoarterial connections.     

Visualization of sinus venosus atrial septal defect by transesophageal echocardiography

Atrial septal defect (ASD) is usually suspected clinically but requires a confirmative diagnostic procedure before surgical repair. Two-dimensional and Doppler echocardiography have high sensitivity and specificity for ASD, but the sensitivity of echocardiography is not as high in detecting sinus venosus ASD as it is in ostium primum or secundum defect because of the difficulty in visualizing the sinus venosus area from the subcostal window. For the posteriorly located cardiac structures, including the atrial septum, visualization is superior by transesophageal echocardiography. We describe a case in which sinus venosus ASD was not visualized by conventional transthoracic echocardiography but was diagnosed confidently by transesophageal echocardiography.     

Intraoperative evaluation of mitral valve regurgitation and repair by transesophageal echocardiography: incidence and significance of systolic anterior motion.

OBJECTIVE. This study was designed to delineate the utility and results of intraoperative transesophageal echocardiography in the evaluation of patients undergoing mitral valve repair for mitral regurgitation. BACKGROUND. Mitral valve reconstruction offers many advantages over prosthetic valve replacement. Intraoperative assessment of valve competence after repair is vital to the effectiveness of this procedure. METHODS. Intraoperative transesophageal echocardiography was performed in 143 patients undergoing mitral valve repair over a period of 23 months. Before and after repair, the functional morphology of the mitral apparatus was defined by two-dimensional echocardiography; Doppler color flow imaging was used to clarify the mechanism of mitral regurgitation and to semiquantitate its severity. RESULTS. There was significant improvement in the mean mitral regurgitation grade by composite intraoperative transesophageal echocardiography after valve repair (3.6 +/- 0.8 to 0.7 +/- 0.7; p less than 0.00001). Excellent results from initial repair with grade less than or equal to 1 residual mitral regurgitation were observed in 88.1% of patients. Significant residual mitral regurgitation (grade greater than or equal to 3) was identified in 11 patients (7.7%); 5 underwent prosthetic valve replacement, 5 had revision of the initial repair and 1 patient had observation only. Of the 100 patients with a myxomatous mitral valve, the risk of grade greater than or equal to 3 mitral regurgitation after initial repair was 1.7% in patients with isolated posterior leaflet disease compared with 22.5% in patients with anterior or bileaflet disease. Severe systolic anterior motion of the mitral apparatus causing grade 2 to 4 mitral regurgitation was present in 13 patients (9.1%) after cardiopulmonary bypass. In 8 patients (5.6%), systolic anterior motion resolved immediately with correction of hyperdynamic hemodynamic status, resulting in grade less than or equal to 1 residual mitral regurgitation without further operative intervention. Transthoracic echocardiography before hospital discharge demonstrated grade less than or equal to 1 residual mitral regurgitation in 86.4% of 132 patients studied. A significant discrepancy (greater than 1 grade) in residual mitral regurgitation by predischarge transthoracic versus intraoperative transesophageal echocardiography was noted in 17 patients (12.9%). CONCLUSIONS. Transesophageal echocardiography is a valuable adjunct in the intraoperative assessment of mitral valve repair.     

Echocardiographic features of straddling tricuspid valve.

Echocardiographic features were studied in four patients with straddling tricuspid valve, a rare and complex cardiac anomaly that may defy diagnosis by angiocardiography. The most significant echocardiographic feature was a septal echo recorded at a depth corresponding to the midportion of the tricuspid valve with one of the tricuspid valve leaflets opening posterior to the ventricular septum in diastole. Certain of the features, which appear to be distinctive for this anomaly, have not previously been described.     

Intraoperative two-dimensional Doppler echocardiography. A preliminary study for congenital heart disease

Intraoperative two-dimensional echocardiograms were performed in 30 patients (group I) and two-dimensional Doppler color flow imaging was performed in 30 additional patients (group II) with various forms of congenital heart disease. A comparative complete two-dimensional Doppler and color flow examination was performed in group II patients 10 to 14 days postoperatively. Standard intraoperative two-dimensional echocardiograms demonstrated excellent correlation with preoperative findings and allowed assessment of valvular regurgitation or shunt when combined with echocardiographic contrast injections. However, intraoperative and postoperative two-dimensional color flow imaging was obtained more easily and rapidly and allowed recognition of more postoperative residual defects. Color flow imaging appears to be a useful method for intraoperative assessment of surgical repair of congenital cardiac defects. Twenty-one residual lesions were correctly diagnosed intraoperatively, whereas seven residual lesions were demonstrated only during later postoperative examination. This preliminary experience has also demonstrated several areas for future development and improvement of these techniques. Combined two-dimensional Doppler and contrast echocardiographic studies may allow better disclosure of residual defects.