ABSTRACT
A time-resolved laser fluorescence spectroscopy (TRLFS) study was carried out to investigate the Eu(III)-SO4 complexation at room temperature over a wide range of Na2SO4 concentrations (0-2 mol kg-1). Spectroscopic observations confirm the step-wise formation of the aqueous complexes Eu(SO4)+, Eu(SO4)2- and Eu(SO4)33- over the investigated Na2SO4 concentrations. Combining TRLFS data obtained in this study and solubility data reported in Part I of this work for the Eu2(SO4)3-Na2SO4-H2O and Eu2(SO4)3-MgSO4-H2O systems, thermodynamic and activity models were derived based on the SIT and Pitzer formalisms. A combination of the geochemical calculation codes PhreeqC (SIT), PhreeSCALE (Pitzer) and the parameter estimation code PEST was used to determine the solubility products of Eu2(SO4)3·8H2O(cr) and Na2Eu2(SO4)4·2H2O(cr), stability constants of the Eu(III)-SO4 complexes (ß0i), and the specific binary and ternary interaction parameters (εij, ß(0)ij, ß(1)ij, CÏij, θik, Ψijk) for both activity models. The thermodynamic constants determined in this work are discussed with reference to values available in the literature.
ABSTRACT
The speciation, thermodynamics and structure of the Np(v) (as the NpO2+ cation) complexes with oxalate (Ox2-) are studied by different spectroscopic techniques. Near infrared absorption spectroscopy (Vis/NIR) is used to investigate complexation reactions as a function of the total ligand concentration ([Ox2-]total), ionic strength (Im = 0.5-4.0 mol kg-1 Na+(Cl-/ClO4-)) and temperature (T = 20-85 °C) for determination of the complex stoichiometry and thermodynamic functions (log ß0n(T), ΔrH0n, ΔrS0n). Besides the solvated NpO2+ ion, two NpO2+ oxalate species (NpO2(Ox)n1-2n; n = 1, 2) are identified. With increasing temperature a decrease of the molar fractions of the 1 : 1 - and 1 : 2 - complexes is observed. Application of the law of mass action yields the temperature dependent conditional stability constants log ß'n(T) at a given ionic strength which are extrapolated to IUPAC reference state conditions (Im = 0) according to the specific ion interaction theory (SIT). The log ß0n(T) values of both complex species (log ß01(25 °C) = 4.53 ± 0.12; log ß02(25 °C) = 6.22 ± 0.24) decrease with increasing temperature confirming an exothermic complexation reaction. The temperature dependence of the thermodynamic stability constants is described by the integrated van't Hoff equation yielding the standard reaction enthalpies (ΔrH01 = -1.3 ± 0.7 kJ mol-1; ΔrH02 = -8.7 ± 1.4 kJ mol-1) and entropies (ΔrS01 = 82 ± 2 J mol-1 K-1; ΔrS02 = 90 ± 5 J mol-1 K-1) for the complexation reactions. In addition, the sum of the specific binary ion-ion interaction coefficients Δε0n(T) for the complexation reactions are obtained from SIT modelling as a function of the temperature. The structure of the complexes and the coordination mode of oxalate are investigated using EXAFS spectroscopy and quantum chemical calculations. The results show, that in case of both species NpO2(Ox)- and NpO2(Ox)23-, chelate complexes with 5-membered rings are formed.
ABSTRACT
Regional centers performing vascular surgery in Austria (nâ¯= 15) were invited in mid-April 2020 by the Austrian Society of Vascular Surgery (ÖGG) to participate in a nationwide survey about implications of the COVID-19 pandemic. Ultimately, a total of 12 centers (80%) answered the questionnaire.All centers were confronted with patients who tested positive for COVID-19 and 75% also had medical personnel who were positive. In contrast, only 25% of the departments of vascular surgery had positively tested patients and 33% had positive staff members. In all departments of vascular surgery elective vascular procedures were either stopped (cancelled or deferred) or selectively limited, including patients with asymptomatic carotid stenosis, aortic aneurysms smaller than 7â¯cm, peripheral arterial aneurysm, peripheral artery occlusive disease Fontaine stage II and varicosities. All centers continued to carry out operations for all types of vascular surgical emergencies. The strategies of the centers were heterogeneous for patients with chronic ulcers, chronic mesenteric insufficiency, asymptomatic aortic aneurysms larger than 7â¯cm and shunt surgery.Decisions on surgery cancellation seemed to be particularly problematic due to the uncertain time period of the COVID-19 measures. As a consequence, the risk associated with cancellation or delayed treatment was difficult to assess. At present, especially indications with nonuniform management strategies need selective attention and additional analysis in single center and multicenter studies. In addition, patients might suffer from relevant psychological problems because of surgery cancellations. Changes in the daily routine due to the COVID-19 pandemic may have a long-term impact on health status and may show significant demographic and geographic variations.
ABSTRACT
Objetivo: La PET con 18F-fluoro-L-dihidroxifenilalanina (18F-DOPA) ofrece alta sensibilidad y especificidad en el diagnóstico del paraganglioma extraadrenal no maligno (PGL) y el feocromocitoma (FEO), pero menor sensibilidad en la enfermedad metastásica. Estos tumores son de origen neuroendocrino y pueden detectarse mediante PET con 68Ga-DOTA-Tyr3-octreótido (68Ga-DOTA-TOC). Por tanto, comparamos 68Ga-DOTA-TOC y 18F-DOPA como radiotrazadores para PET/TC para el diagnóstico de PGL extradrenal metastásico y FEO. Las imágenes tomográficas anatómicas y funcionales fusionadas se utilizaron como estándar de referencia. Métodos: Se incluyó en el estudio a un total de 6 varones y 4 mujeres (rango de edad de 22 a 72 años), con PGL metastásico y FEO anatómica y/o histológicamente demostrados. De entre estos pacientes, 2 varones padecían FEO y los 8 pacientes restantes PGL extraadrenal metastásico. La evaluación comparativa incluyó imagen morfológica con TC e imagen funcional mediante PET con 68Ga-DOTA-TOC y 18F-DOPA. Se analizaron los resultados de las imágenes por lesión. Se midió el valor máximo de captación estandarizado (SUVmáx) de cada modalidad de imagen funcional en las lesiones tumorales concordantes. Resultados: En comparación con la imagen anatómica, la tasa de detección por lesión mediante PET con 68Ga-DOTA-TOC fue del 100% (McNemar, p<0,01), y la de PET con 18F-DOPA fue del 82,3% (McNemar, p<0,8) para PGL extraadrenal metastásico y FEO. En general, la PET con 68Ga-DOTA-TOC identificó 67 lesiones, la imagen anatómica identificó 62 lesiones y la PET con 18F-DOPA identificó 56 lesiones. El valor SUVmáx (media±DE) de todas las lesiones concordantes fue de 29,3±19,9 para la PET con 68Ga-DOTA-TOC, y de 12,3±9,1 para la PET con 18F-DOPA (prueba U de Mann-Whitney, p<0,0001). Conclusión: La PET con 68Ga-DOTA-TOC proporciona un índice de detección más elevado en el PGL extra-adrenal metastásico y PHEO, en comparación con la PET con 18F-DOPA, e incluso con la TC diagnóstica, particularmente en lo referente a lesiones óseas. La imagen funcional/anatómica combinada (PET/TC con 68Ga-DOTA-TOC) permite detectar la extensión exacta del tumor en estas entidades tumorales infrecuentes, especialmente en caso de correlación anatómica incierta
Objective: 18F-Fluoro-L-dihydroxyphenylalanine (18F-DOPA) PET offers high sensitivity and specificity in the imaging of non-malignant extra-adrenal paraganglioma (PGL) and pheochromocytoma (PHEO) but lower sensitivity in metastatic disease. These tumours are of neuroendocrine origin and can be detected by 68Ga-DOTA-Tyr3-octreotide (68Ga-DOTA-TOC) PET. Therefore, we compared 68Ga-DOTA-TOC and 18F-DOPA as radiolabels for PET/CT imaging for the diagnosis of metastatic extra-adrenal PGL and PHEO. Combined cross-sectional imaging was the reference standard. Methods: A total of 6 men and 4 women (age range 22-72 years) with anatomical and/or histologically proven metastatic PGL and PHEO were included in this study. Of these patients, 2 male patients suffered from PHEO, while the remaining 8 patients were diagnosed as metastatic extra-adrenal PGL disease. Comparative evaluation included morphological imaging with CT and functional imaging with 68Ga-DOTA-TOC and 18F-DOPA PET. The imaging results were analyzed on a per-lesion basis. The maximum standardized uptake value (SUVmax) of each functional imaging modality in concordant tumour lesions was measured. Results: Compared with anatomical imaging, the per-lesion detection rate of 68Ga-DOTA-TOC was 100% (McNemar, P<0.01), and that of 18F-DOPA PET was 82.3% (McNemar, P<0.8) in metastatic extra-adrenal PGL and PHEO. Overall, 68Ga-DOTA-TOC PET identified 67 lesions; anatomical imaging identified 62 lesions, and 18F-DOPA PET identified 56 lesions. The SUVmax (mean±SD) of all concordant lesions was 29.3±19.9 for 68Ga-DOTA-TOC PET and 12.3±9.1 for 18F-DOPA PET (Mann-Whitney U test, P<0.0001). Conclusion: 68Ga-DOTA-TOC PET offers the highest detection rate in metastatic extra-adrenal PGL and PHEO compared to 18F-DOPA PET and even to diagnostic CT, particularly in bone lesions. Combined functional/anatomical imaging (68Ga-DOTA-TOC PET/CT) enables exact tumour extension to be detected in these rare tumour entities, especially in the case of unclear anatomical correlation
Subject(s)
Humans , Male , Female , Young Adult , Adult , Middle Aged , Aged , Pheochromocytoma/diagnostic imaging , Paraganglioma, Extra-Adrenal/diagnostic imaging , Fluorodeoxyglucose F18 , Positron Emission Tomography Computed Tomography/methods , Gadolinium DTPA , PC12 Cells/pathology , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
OBJECTIVE: 18F-Fluoro-L-dihydroxyphenylalanine (18F-DOPA) PET offers high sensitivity and specificity in the imaging of non-malignant extra-adrenal paraganglioma (PGL) and pheochromocytoma (PHEO) but lower sensitivity in metastatic disease. These tumours are of neuroendocrine origin and can be detected by 68Ga-DOTA-Tyr3-octreotide (68Ga-DOTA-TOC) PET. Therefore, we compared 68Ga-DOTA-TOC and 18F-DOPA as radiolabels for PET/CT imaging for the diagnosis of metastatic extra-adrenal PGL and PHEO. Combined cross-sectional imaging was the reference standard. METHODS: A total of 6 men and 4 women (age range 22-72 years) with anatomical and/or histologically proven metastatic PGL and PHEO were included in this study. Of these patients, 2 male patients suffered from PHEO, while the remaining 8 patients were diagnosed as metastatic extra-adrenal PGL disease. Comparative evaluation included morphological imaging with CT and functional imaging with 68Ga-DOTA-TOC and 18F-DOPA PET. The imaging results were analyzed on a per-lesion basis. The maximum standardized uptake value (SUVmax) of each functional imaging modality in concordant tumour lesions was measured. RESULTS: Compared with anatomical imaging, the per-lesion detection rate of 68Ga-DOTA-TOC was 100% (McNemar, P<0.01), and that of 18F-DOPA PET was 82.3% (McNemar, P<0.8) in metastatic extra-adrenal PGL and PHEO. Overall, 68Ga-DOTA-TOC PET identified 67 lesions; anatomical imaging identified 62 lesions, and 18F-DOPA PET identified 56 lesions. The SUVmax (mean±SD) of all concordant lesions was 29.3±19.9 for 68Ga-DOTA-TOC PET and 12.3±9.1 for 18F-DOPA PET (Mann-Whitney U test, P<0.0001). CONCLUSION: 68Ga-DOTA-TOC PET offers the highest detection rate in metastatic extra-adrenal PGL and PHEO compared to 18F-DOPA PET and even to diagnostic CT, particularly in bone lesions. Combined functional/anatomical imaging (68Ga-DOTA-TOC PET/CT) enables exact tumour extension to be detected in these rare tumour entities, especially in the case of unclear anatomical correlation.
Subject(s)
Adrenal Gland Neoplasms/diagnostic imaging , Dihydroxyphenylalanine/analogs & derivatives , Organometallic Compounds , Paraganglioma, Extra-Adrenal/diagnostic imaging , Pheochromocytoma/diagnostic imaging , Positron Emission Tomography Computed Tomography/methods , Adult , Aged , Female , Humans , Male , Middle Aged , Retrospective Studies , Young AdultABSTRACT
OBJECTIVE/BACKGROUND: To analyse long term outcome, including functional status and prognostic factors, in patients who have undergone arterial repair of civilian upper limb injury. Retrospective data analysis of prospectively collected data was performed. METHODS: This was a retrospective data analysis of prospectively collected data. Records of all patients who had undergone repair of traumatic arterial lesions in the upper limb between 1989 and 2010 were reviewed, and clinical follow up was performed. End points were: long term patency, measured by color Doppler ultrasound; vascular re-intervention; limb salvage rate; and long term functional status using the Disabilities of Arm, Shoulder, and Hand (DASH) questionnaire. The DASH questionnaire is an instrument used to identify a patient's disabilities, in which everyday activities are assessed by 30 questions. The DASH answers are summarized and, using a conversion formula, lead to a score between 0 (full recovery) and 100 (severe disability). The DASH questionnaire was sent to all German-speaking individuals for data supplementation after completion of a clinical follow up study. RESULTS: A total of 117 arterial repairs were performed in 108 patients (87 men, median age 35.7 years). Blunt trauma was the predominant cause of injury (n = 96; 82%). Accompanying nerve lesions (n = 39; 36%) and/or orthopedic injuries (n = 65; 60%) were present in 84 patients (78%). After a median follow up time of 5.3 years (range 0.5-19.7 years), 65 patients (60%) were re-investigated: long-term patency was 97%. The DASH questionnaire was answered by 57 patients (53%). Functional impairment was frequently seen, and determined by neurological injury (including neurological lesions, median DASH score was 40.3 [range 3.5-69.8] vs. 0.8 [range 0-5.8] without; p < .001) and ischemia at time of injury (median DASH score with ischemia 4.2 [range 0-16.9] vs. 0.0 [0-1.7] without; p < .04). CONCLUSION: Favorable long term patency rates after arterial repair in upper extremity injuries can be achieved. Long term functional impairment is a significant problem and determined by associated neurological injury, as well as ischemia at time of injury.
Subject(s)
Arm Injuries/surgery , Plastic Surgery Procedures/methods , Activities of Daily Living , Adolescent , Adult , Aged , Aged, 80 and over , Arm/blood supply , Arm Injuries/physiopathology , Arteries/surgery , Child , Child, Preschool , Female , Humans , Male , Middle Aged , Retrospective Studies , Surveys and Questionnaires , Treatment Outcome , Vascular Patency , Vascular Surgical Procedures , Young AdultABSTRACT
AIM: Constant-load treadmill testing is frequently used to estimate walking ability of patients with peripheral arterial disease and to assess changes in functional capacity following therapeutic interventions or through disease progression. The value of this test has frequently been disputed based on doubts concerning its reproducibility. The aim of this study was to investigate the reliability of treadmill testing at a speed of 3 km/h and a constant inclination of 12%. METHODS: Sixty-eight patients with stable peripheral arterial disease who were familiar with treadmill testing underwent two sessions of walking exercise at 3 km/h and 12% inclination within three weeks. Initial claudication distance (ICD) and maximum walking distance (MWD) on the treadmill as well as reported walking distances on level ground at individual speed were recorded. RESULTS: Correlation coefficients of 0.8 and within-subject variation coefficients of 15% for ICD and 13% for MWD demonstrated low variability of walking distances between visits. No learning effects were observed. Intra-class correlation coefficients of 0.78 for ICD and 0.83 for MWD proved good reproducibility of treadmill testing. Correlation of measured and reported walking distances was poor. CONCLUSION: Constant-load treadmill testing at 3km/h and 12% inclination is a well reproducible method to investigate walking capacity of patients with stable intermittent claudication who are familiar with this test method. From treadmill walking distances, no conclusions should be drawn concerning the actual walking range of the patient.
