838 research outputs found
Increased radioiodine uptake of thyroid cell cultures after external irradiation
No full textBackground: Radioiodine uptake (RIU) is one of the main prognostic factors for curative results of radioiodine therapy in patients with differentiated thyroid cancer. Some days after application of I-131, the uptake of a subsequent administration of radioiodine was found to be reduced. In contrast, early after irradiation with high-energy photons glucose and amino acid uptake were observed to be increased. Effects of external irradiation on RIU of thyrocytes using high-energy photons have not been investigated so far. Material and Methods: Two different cell lines (FRTL-5 and ML-1 cells) derived from thyroid tissue were studied in vitro. Cell Lines were either incubated with I-131 only (controls) or additionally irradiated with single doses of 6 or 10 Gy of high-energy photons using a linear accelerator. Cell number and RIU were determined 24-96 h after I-131 application. RIU measurements were repeated after application of sodium perchlorate in excess to investigate specificity of the uptake. Statistical analyses were performed using non-parametric tests. Results: Incubation with radioiodine as well as irradiation with high-energy photons slowed down proliferation in investigated cell lines significantly. Irradiation with solely I-131 resulted in stable or slightly decreased iodide uptake. Compared to those cells, the RIU increased significantly in externally irradiated cells, i.e., additional irradiation with 10 Gy resulted in an almost threefold increase of RIU in FRTL-5 after 72 h. The increase of RIU after irradiation was dose-dependent in both cell lines and could be blocked by perchlorate excess. Conclusion: It could be demonstrated that external irradiation increases RIU in thyroid cell cultures early after irradiation. The increase was dose-dependent and specific, as it could be blocked by perchlorate. This effect appears to be similar to the increase of other actively transported substances after irradiation with high-energy photons. Therefore, the results of this study may contribute to the knowledge of a generalized irradiation-induced mechanism which causes the activation of different cellular transporters. The clinical impact of these findings on combined therapy concepts has to be investigated in further experiments
Diagnostic I-121 and I-131 activities and radioiodine therapy - Effects on urinary iodine excretion in patients with differentiated thyroid carcinoma
No full textAim: Urinary iodine excretion (UIE) provides information about iodine supply and release. lathe present study we investigated effects of the application of different radioiodine isotopes on UIE in patients with differentiated thyroid carcinoma (DTC). Patients, methods: In 91 consecutive patients with DTC UIE, measured as iodine/creatinine ratio, was determined before and after application of I-123 and I-131 for diagnostic or therapeutic purposes. Additionally, remnant volume (V) was determined prior to therapy. Group A consisted of 33 patients with supposed successful ablation of DTC. These patients received 370 MBq I-131 for diagnostic use and served as controls. 58 patients (group B) with remnants, relapses and metastases received 370 MBq I-123 for diagnostics prior to therapy with 1.5-22.2 GBq I-131. Factors influencing individual changes in urinary iodine excretion (Delta UIE) were investigated by using non-parametric tests. Results: In group A WE did not change significantly after application of I-131. As well, UIE remained unchanged after diagnostic application of I-123 in group B. In contrast, UIE increased significantly already 24 h after therapeutic application of I-131 in this group. In patients with small remnants (V < 2.5 ml) a significant but only moderate increase of WE could be observed (average increase: 47 mu g l/g crea). In patients with larger remnants, with relapses or metastases increase of UIE values was significant and more pronounced. Conclusions: It was confirmed that UIE increased significantly during radioiodine therapy in patients with DTC and radioiodine-accumulating tissue. The increase of WE after therapeutic administration of radioiodine can be explained by the disintegrated thyroid follicles in thyroid remnants. The radioiodine-induced iodine release may be one reason for thyroid "stunning" even after application of diagnostic amounts of I-131
Diagnostic I-121 and I-131 activities and radioiodine therapy - Effects on urinary iodine excretion in patients with differentiated thyroid carcinoma
No full textAim: Urinary iodine excretion (UIE) provides information about iodine supply and release. lathe present study we investigated effects of the application of different radioiodine isotopes on UIE in patients with differentiated thyroid carcinoma (DTC). Patients, methods: In 91 consecutive patients with DTC UIE, measured as iodine/creatinine ratio, was determined before and after application of I-123 and I-131 for diagnostic or therapeutic purposes. Additionally, remnant volume (V) was determined prior to therapy. Group A consisted of 33 patients with supposed successful ablation of DTC. These patients received 370 MBq I-131 for diagnostic use and served as controls. 58 patients (group B) with remnants, relapses and metastases received 370 MBq I-123 for diagnostics prior to therapy with 1.5-22.2 GBq I-131. Factors influencing individual changes in urinary iodine excretion (Delta UIE) were investigated by using non-parametric tests. Results: In group A WE did not change significantly after application of I-131. As well, UIE remained unchanged after diagnostic application of I-123 in group B. In contrast, UIE increased significantly already 24 h after therapeutic application of I-131 in this group. In patients with small remnants (V < 2.5 ml) a significant but only moderate increase of WE could be observed (average increase: 47 mu g l/g crea). In patients with larger remnants, with relapses or metastases increase of UIE values was significant and more pronounced. Conclusions: It was confirmed that UIE increased significantly during radioiodine therapy in patients with DTC and radioiodine-accumulating tissue. The increase of WE after therapeutic administration of radioiodine can be explained by the disintegrated thyroid follicles in thyroid remnants. The radioiodine-induced iodine release may be one reason for thyroid "stunning" even after application of diagnostic amounts of I-131
Status of the R&D activities for the upgrade of the ALICE TPC
No full textAfter the Long Shutdown 2 (LS2) the LHC will provide lead–lead collisions at interaction rates as high as 50 kHz. In order to cope with such conditions the ALICE Time Projection Chamber (TPC) needs to be upgraded.
After the upgrade the TPC will run in a continuous mode, without any degradation of the momentum and dE/dx resolution compared to the performance of the present TPC. Since readout by multi-wire proportional chambers is no longer feasible with these requirements, new technologies have to be employed. In the new readout chambers the electron amplification is provided by a stack of four Gas ElectronMultiplier (GEM) foils. Here foils with a standard hole pitch of 140 μm as well as large pitch foils (280 μm) are used. Their high voltage settings and orientation have been optimised to provide an energy resolution of σE/E ≤ 12% at the photopeak of 55Fe. At the same settings the Ion BackFlow into the drift volume is less than 1% of the effective number of ions produced during gas amplification and the primary ionisations. This is necessary to prevent the accumulation of space charge, which eventually will distort the field in the drift volume. To ensure stable operation at the high loads during LHC run 3 the chambers have to be robust against discharges, too. With the selected configuration in a quadruple GEMstack the discharge probability is kept at the level of 10-12 discharges per incoming hadron. An overview of the ALICE TPC upgrade activities will be given in these proceedings and the optimised settings foreseen for the GEM stacks of the future readout chambers are introduced. Furthermore the outcome of two beam time campaigns at SPS and PS (at CERN) in the end of 2014 is shown. At this campaigns the stability against discharges and the dE/dx performance of a full size readout chamber prototype was tested. In addition it is reported on charging-up studies of 4GEM stacks and on tests of electromagnetic sagging of large GEM foils
Développement Durable et Attractivité des territories: le cas des pays de l’Adour
No full textInternational audienc
De la théorie de la croissance au conflit de convergence dans les Pays du Sud et de l'Est de la Méditerranée : revue de la littérature et approche théorique
No full textInternational audienc
Etude comparée : Lien Intégration/Convergence en Asie du Sud-est et dans les Pays du Sud et de l’Est Méditerranéen
No full textInternational audienc
Etude comparative : l’intégration commerciale facteur de convergence réelle, les cas des pas d’Asie du Sud-est, des MENA et des pays d’Amérique Latine
No full textInternational audienc
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