Electrochemical Pseudo-Titration of Water-Soluble Antioxidants

An amperometric test for the antioxidant power (AOP) of biological and food samples is presented. The gist of the method is to measure by linear sweep voltammetry the anodic current produced during the oxidation of the labile species present in the sample and then rationalizing this signal with a mathematical treatment that allows the pseudo-titration of antioxidants (AOs) around a given threshold potential. As a result, the AOP of the sample is calculated. This method allows the discrimination of the most biologically relevant AOs that react rapidly and at low oxidation potentials, from less reactive AOs that are oxidised slowly and at much higher oxidation potentials. This methodology was applied for measuring the AOP of blood, saliva, and natural drinks like orange juice

Value of I-123-MIBG Scintigraphy in Paraganglioma

Aim: The aim of the study was to evaluate the current role of I-123-MIBG scintigraphy in the detection and follow-up of patients with paragangliomas. Materials and Methods: 117 patients were referred for diagnostic I-123-MIBG scintigraphy based on a strong clinical suspicion, positive familial history and genetic testing, or for follow-up of paragangliomas. I-123-MIBG images were analyzed and correlated with In-111-octreotide scintigraphy, CT or MRI results. Accuracy of the imaging method was calculated per patient and per tumor per site. Results: A total of 117 patients were referred for I-123-MIBG diagnostic imaging; 80 patients were diagnosed with paraganglioma; 66 patients had a single neuroendocrine tumor and 14 patients multiple tumors. The total number of all lesions in these patients was 172. I-123-MIBG scintigraphy demonstrated 65 lesions in 56 patients (overall sensitivity: 56.3%, specificity: 84%). Lesion-per-site analysis revealed that sensitivity and specificity significantly varied per tumor site (lowest sensitivity for the head and neck: 17.5% and lowest specificity for the abdomen: 87.5%). Hormones were elevated in 85 patients: 55 I-123-MIBG tumors were positive and 35 tumors were negative. In 16 patients (13.7%) with a genetic burden and a single neuroendocrine tumor, I-123-MIBG whole-body imaging was successful at detecting a second tumor. In 2 patients (1.7%) with paragangliomas, I-123-MIBG unexpectedly detected metastases, so the restaging was properly done. Conclusion: I-123-MIBG scintigraphy remains important in pheochromocytoma and functioning neuroendocrine tumors. The value of I-123-MIBG scintigraphy is high in familial syndromes with multiple neuroendocrine tumors at different sites, multifocal tumors, and relapsing and metastatic disease. Copyright (C) 2009 S. Karger AG, BaselDiabetes mellitus: pathophysiological changes and therap