| 1. |
- Adrian, Gabriel, et al.
(author)
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Cancer Cells Can Exhibit a Sparing FLASH Effect at Low Doses Under Normoxic In Vitro-Conditions
- 2021
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In: Frontiers in Oncology. - : Frontiers Media SA. - 2234-943X. ; 11
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Journal article (peer-reviewed)abstract
- Background: Irradiation with ultra-high dose rate (FLASH) has been shown to spare normal tissue without hampering tumor control in several in vivo studies. Few cell lines have been investigated in vitro, and previous results are inconsistent. Assuming that oxygen depletion accounts for the FLASH sparing effect, no sparing should appear for cells irradiated with low doses in normoxia. Methods: Seven cancer cell lines (MDA-MB-231, MCF7, WiDr, LU-HNSCC4, HeLa [early passage and subclone]) and normal lung fibroblasts (MRC-5) were irradiated with doses ranging from 0 to 12 Gy using FLASH (≥800 Gy/s) or conventional dose rates (CONV, 14 Gy/min), with a 10 MeV electron beam from a clinical linear accelerator. Surviving fraction (SF) was determined with clonogenic assays. Three cell lines were further studied for radiation-induced DNA-damage foci using a 53BP1-marker and for cell cycle synchronization after irradiation. Results: A tendency of increased survival following FLASH compared with CONV was suggested for all cell lines, with significant differences for 4/7 cell lines. The magnitude of the FLASH-sparing expressed as a dose-modifying factor at SF=0.1 was around 1.1 for 6/7 cell lines and around 1.3 for the HeLasubclone. Similar cell cycle distributions and 53BP1-foci numbers were found comparing FLASH to CONV. Conclusion: We have found a FLASH effect appearing at low doses under normoxic conditions for several cell lines in vitro. The magnitude of the FLASH effect differed between the cell lines, suggesting inherited biological susceptibilities for FLASH irradiation.
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| 2. |
- Arrigan, Damien, et al.
(author)
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Selective voltammetric detection of dopamine in the presence ofascorbate
- 2004
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In: Chemical Communications. - : Royal Society of Chemistry. - 1359-7345 .- 1364-548X. ; :6, s. 732-733
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Journal article (peer-reviewed)abstract
- The selective detection of dopamine in the presence of ascorbateis demonstrated based on the voltammetry of dopamine transferacross the interface between two immiscible electrolyte solutions(ITIES) facilitated by an organic-phase ionophore; ascorbatetransfer does not occur, leading to highly selectivedetection of dopamine in the presence of excess ascorbate.
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| 3. |
- Beni, Valerio, et al.
(author)
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Cyclic and pulse voltammetric study of dopamine at the interfacebetween two immiscible electrolyte solutions
- 2005
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In: Biosensors & bioelectronics. - : Elsevier. - 0956-5663 .- 1873-4235. ; 20:10, s. 2097-2103
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Journal article (peer-reviewed)abstract
- The detection of dopamine by differential pulse voltammetry (DPV) and square wave voltammetry (SWV) at the interface between twoimmiscible electrolyte solutions (ITIES) has been studied. Voltammetry at the liquid/liquid (water/1,2-dichloroethane) interface provides asimple method for overcoming the major problem associated with dopamine detection by voltammetry at solid electrodes: the co-existenceof ascorbate at higher concentrations. Selectivity for dopamine was achieved by the use of dibenzo-18-crown-6 as an ionophore for thefacilitated transfer voltammetry of protonated dopamine across the ITIES. Under these conditions, ascorbate is not transferred and hence doesnot interfere in the ion transfer current for dopamine. By use of DPV and SWV, the lowest concentration detectable can be lowered from ca.0.1mM (obtained with cyclic voltammetry) to 2 M. Evaluation of the effect of some other physiologically important species (acetylcholine,sodium, potassium and ammonium ions) on the dopamine transfer voltammetry has been studied, indicating the need for improved ionophoredesigns in order to achieve practically useful selectivity.
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